Study of Possible Proton-Antiproton Hexaquark State in Lattice QCD

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GRE英语考试模拟试卷及答案解析(14)

GRE英语考试模拟试卷及答案解析（14） 选择图片第31题BOLSTER:A.demystifyB.opposeC.eraseD.abandonE.separate参考答案： B 您的答案：未作答答案解析：上一题成绩单答题卡。

Target

TargetA thin target scheme for the Muon sourceAlain Blondel a,Jean Paul Fabre b,Simone Gilardoni c,Nikolaos Vassilopoulos ba LPNHE,Ecole Polytechnique,91128Palaiseau Cedex,Franceb Cern,1211,Geneva23,Switzerlandc INFN Milano and Politecnico di Milano,Milano,ItalyThe purpose of this paper is to perform a preliminary analysis of a thin target and recirculator scheme for the pion source of a muon machine such as a Neutrino Factory.A sketch of this is shown in Figure1.This is similar to studies performed for antiproton sources(1).Protons incoming from the source(i.e.a linac or a synchrotron)interact with a thin target and produce pions.Most protons do not interact and are capturedFig.1.Schema for the recirculating scenarioPreprint submitted to Elsevier Preprint4November1999in a recirculator which sends them back onto the target for several turns. There is no need for a dump,since all the protons produced by the injector are eventually absorbed in the target.The target can thus be thin(at limit point-like)and composed of low-Z materials which have the advantage of not producing heavy radioactive nuclei.This scheme could also be considered with an H?linac,the target acting in this case as a strip foil.This scheme leads to a number of questions:i)will multiple scattering in the target increase the emittance so much that cooling of the protons should be necessary?ii)the energy deposited in the target is very localised and could become unbearable;iii)the accumulated current in the recirculator might be too high,iv)with the protons recirculating,the time structure of the pion beam acquires a structure at about one microsecond.Although these implica-tions will not?nd here an answer in the context of a consistent scenario of a Neutrino Factory,they are addressed in turn.1Multiple scatteringThe proton beam is spread by multiple scattering according to a characteristic angleθ0:13.6(GeV)xθ0=εin/βwhereεis the emittance of the beam andβthe optical focusing function at the target.After one passage in the target the proton beam has a total angular spread which is the quadratic sum of these two contributions.εinσ2θ,out=,where x is the thickness ofX I2the target,and X I is the interaction length for the given material.A typical proton will thus pass through the target X Ix.A similar result is obtained if one?lls the recirculator continuously.Let us now assume that the recirculation time is matched to the timing of the proton injector,as would be the case if the target also acted as an H?strip foil.At every turn a number n0of protons is added to the bunch,with an emittance equal toεin.The remaining fraction(1?a)of the proton beam is assumed to be recovered by the recirculation system.After in?nite number of passages, the total angular divergence of the beam tends to:εequil.=n0∞εin p kn0∞p k(4)where n0p k is the number of particles remaining after k turns,with p k= (1?a)k.With little algebra equation4becomesεequil.=εin+βθ201?aX0(6) whereα20=13.6Mat X I(g/cm2)X0(g/cm2)X IH2O8536 2.361P b(≈Hg)194 6.430.30.08The best is clearly to chose a material with a short interaction length(X I) and a long radiation length(X0).The target thickness could then as long as a few centimetres and remain shorter thanβcrit.2Energy lossAnother constraint for the target choice is given by the energy deposition in the target which is,as a?rst approximation,due to ionization and can be computed using dEdx .The recirculator must thereforebe equipped with a modest amount of re-accelerating devices(typically a few MeV).Since the average total path that every proton eventually undergoes in the tar-get is one interaction length,the total energy loss is given by P loss=dE Mat.dEH2O1698.5%Pb21711%3IntensitySince each proton will remain on average in the recirculator for X Iρ(g/cm3)X I(cm)I equil.=I0·X I/βcrit(A)D20.173250.58Be 1.8540.50.19Here beryllium which o?ers high density and low Z at the same time is the clear winner of the materials considered.4Particle CaptureIt could be an advantage to handle a point-like source.In particular a point-like source can be placed exactly in the focal point of an optical capture device such as a magnetic horn.A study in progress(3)to simulate a horn for the Neutrino Factory taking experience from the NGS studies(4)has already reached a performance similar to that obtained with a solenoid capture can be envisaged.5Time StructureThe favoured operation mode for the Neutrino Factory that emerged from NUFACT99in Lyon would be pulsed operation with a repetition rate of10-50Hz.Pulsed devices being operational for several hundredth of microseconds, and the recirculation time being of less or equal to a microsecond(recirculator ring of less than300meters circumference),there is plenty of time for the protons to recirculate from one or several initial bunches of protons injected in the system.If one starts from one bunch or train of bunches of protons, the recirculator generates then a succession of bunches(or trains)with a time structure equal to the recirculation time and with exponentially decreasing intensity I k=I initial e?k.x/X I.5Provided that the muon storage ring does not have a length that coincides with the recirculating time,it should be possible to store the successive muon bunches in the muon decay ring,provided an RF injection scheme is consid-ered.This recirculator scheme could therefore be acceptable and o?er some advantages for the Neutrino Factory.For Muon Colliders,evidently,the dilu-tion of intensity over so many bunches would result in unacceptable loss of luminosity.6ConclusionsThe possibility of recirculating the protons in a storage ring coupled with a thin target had been investigated.A thin target composed by low-Z material like D2,H2O or Be seems the best choice.The advantages of having a capture system like a magnetic horn,in particular for a thin target scheme,are still under investigation.The timing of the system seems at?rst look acceptable for a Neutrino Factory,but not for a Muon Collider.References[1]N.Mokhov and A.Van Ginneken,Increasing anti-proton yields via re-circulating beam targeting,FERMILAB-FN-621(1994).[2]Particle Data Group,Euro.Phys.Journal C3(1998)76[3]A.Ball,A.Blondel,S.Gilardoni,N.Vassilopoulos,Preliminary mag-netic horn study for the collection scheme of a Neutrino Factory,to appear in the proceedings of NUFACT99,Lyon1999. [4]The CERN Neutrino beam to Gran Sasso(NGS),Addendum to re-port CERN98-02,INFN/AE-98/05,CERN-SL/99-034(DI),INFN/AE-99/05[5]M.Vretenar in Prospective study of Muon Storage Ring at Cern,B.Autin,A.Blondel and J.Ellis eds,CERN99-02(1999)8.6。

A review of the species of protozoan epibionts on crustaceans-11

A REVIEW OF THE SPECIES OF PROTOZOAN EPIBIONTS ONCRUSTACEANS.I.PERITRICH CILIATESBYGREGORIO FERNANDEZ-LEBORANS and MARIA LUISA TATO-PORTODepartamento de Biologia Animal I(Zoologia),Facultad de Biologia,Pnta9a,Universidad Complutense,E-28040Madrid,SpainABSTRACTAn updated inventory of the peritrich(Protozoa,Ciliophora)epibiont species on crustaceans has been carried out.Data concerning268epibiont species,their taxonomic position,and the various crustacean basibionts were considered.The overview comprised in this study may be of use in further surveys of protozoan-crustacean epibiosis.RESUMENSe ha realizado un inventario actualizado de las especies de peritricos(Protozoa,Ciliophora) epibiontes en crustáceos.Se han considerado los datos concernientes a268especies epibiontes,su posición taxonómica,y los diferentes crustáceos visión general que comprende este estudio puede ser utilizada en futuras investigaciones sobre la epibiosis protozoos-crustáceos.INTRODUCTIONEpibiosis is a facultative association of two organisms:the epibiont and the basibiont(Wahl,1989).The term“epibiont”includes organisms that,during the sessile phase of their life cycle,are attached to the surface of a living substratum, while the basibiont lodges and constitutes a support for the epibiont(Threlkeld et al.,1993).Both concepts describe ecological functions(Wahl,1989).Several crustacean groups,cladocerans,copepods,cirripedes,isopods,amphi-pods,and decapods,include forms that are hosts for macroepibiont invertebrates (Ross,1983),and for protozoan microepibionts of the phylum Ciliophora:apos-tomatids,chonotrichids,suctorians,peritrichs,and heterotrichs(Corliss,1979; Small&Lynn,1985).The study of ciliate epibionts on crustaceans began in the last century.Bütschli(1887-89)made a compilation from former publications.After-wards,other authors(Keiser,1921;Kahl,1934,1935;Precht,1935;Raabe,1947; c®Koninklijke Brill NV,Leiden,2000Crustaceana73(6):643-683644G.FERNANDEZ-LEBORANS&M.L.TATO-PORTONenninger,1948)not only described epibiont species,but proposed explanations for the processes of epibiosis.A review of the protozoan epibionts found on de-capod crustaceans was carried out by Sprague&Couch(1971).Green(1974), in a study of the epibionts living on cladocerans,pays considerable attention to protozoan species.Ho&Perkins(1985)have focused on the epibionts found on copepods.In other contemporary and also earlier works,the following aspects have been taken into account:(1)speci city between ciliates and their crustacean basi-bionts(Evans et al.,1981;Batisse,1986,1992;Clamp,1991);(2)the morpholog-ical and physiological adaptations of the epibionts(D’Eliscu,1975;Batisse,1986, 1994;Fenchel,1987;Clamp,1991;Lom&De Puytorac,1994);(3)the effects pro-duced by the epibionts on the crustaceans(Herman et al.,1971;Turner et al.,1979; Kankaala&Eloranta,1987;Nagasawa,1988);(4)the possible use of epibionts for the assessment of water quality(Antipa,1977;Henebry&Ridgeway,1979;Scott &Thune,1986);(5)the implications of protozoan epibionts on cultures of vari-ous species of crustaceans(Overstreet,1973;Johnson,1977,1978;Lightner,1977, 1988;Couch,1978;Scott&Thune,1986;V ogelbein&Thune,1988;Camacho& Chinchilla,1989);and(6)the organization of the epibiont communities on plank-tonic crustaceans(Threlkeld et al.,1993).Despite the fact that there is a considerable amount of information about the protozoan epibionts on crustaceans,since the works of Sprague&Couch(1971), Green(1974),and Ho&Perkins(1985),which relate to speci c crustacean groups, no further general reviews have appeared.Several new species of protozoan ciliate epibionts have recently been described(Dovgal,1985;Batisse,1992;Fernandez-Leborans&Gomez del Arco,1996;Zhadan&Mikrjukov,1996;Fernandez-Leborans et al.,1996,1997),and some of these are peritrich ciliates(Matthes& Guhl,1973;Bierhof&Roos,1977;Jankowski,1986;Dale&Blom,1987;Clamp, 1990,1991;Threlkeld&Willey,1993;Hudson&Lester,1994;Stoukal&Matis, 1994;Foissner,1996).The purpose of this work is to provide an up-to-date review of the peritrich ciliates living as epibionts on crustaceans:268species have been considered in this compilation,which may contribute data for studies of epibiosis in crustaceans.CRUSTACEAN PROTOZOAN EPIBIONTS,I.PERITRICH CILIATES645RESULTS1)Phylum CILIOPHORA Do ein,1901Class OLIGOHYMENOPHOREA De Puytorac,Batisse,Bohatier,Corliss, Deroux,Didier,Dragesco,Fryd-Versavel,Grain,Grolière,Hovasse,Iftode,Laval,Roque,Savoie&Tuffrau,1974Subclass P ERITRICHIA Calkins,1933Order S ESSILIDA Kahl,1933Family Epistylididae Kahl,1935Genus Rhabdostyla Kent,1880( g.1)R.bosminae Levander,1907.On the cladoceran Bosmina sp.R.conipes Kahl,1935.On the cladoceran Daphnia sp.Fresh water.On the cladocerans Daphnia magna,D.longispina and Scapholeberis mucronata (cf.Green,1957,1974).R.cyclopis Kahl,1935.On the copepod Cyclops sp.Fresh water.R.cylindrica Stiller,1935.On the cladoceran Leptodora ke Balaton (Hungary).On the cladoceran Leptodora kindtii.Denmark(Green,1974).R.hungarica Stiller,1931.On the cladoceran Leptodora ke Balaton (Hungary).R.globularis Stokes,1890.On the cladoceran Bosmina longirostris and on Diaphanosoma brachyurum.Germany(Nenninger,1948).R.invaginata Stokes,1886.On the ostracod Cypris sp.R.sessilis Penard,1922.On the copepod Cyclops sp.Fresh water.R.pyriformis Perty,1852(cf.Kahl,1935;on Entomostraca).On the clado-ceran Daphnia longispina(cf.Nenninger,1948).On the cladoceran Daph-nia hyalina(cf.Sommer,1950).On Daphnia pulex and Ceriodaphnia reticu-lata(cf.Hamman,1952).On Daphnia magna,D.pulex,D.cucullata,Simo-cephalus vetulus,Ceriodaphnia reticulata,and Leptodora kindtii(cf.Green, 1953).On Daphnia magna(cf.Green,1955).On Daphnia magna andD.longispina(cf.Green,1957).On Daphnia atkinsoni,D.hyalina,D.lon-gispina,D.curvirostris,D.obtusa,Ceriodaphnia laticaudata,and C.pulchel-la(cf.Green,1974).R.vernalis Stokes,1887.On the copepod Eucyclops agilis(cf.Henebry& Ridgeway,1979).1)For authors and dates of species of Crustacea mentioned herein,see separate section,below.646G.FERNANDEZ-LEBORANS&M.L.TATO-PORTOFigs.1-2.1,Rhabdostyla(R.pyriformis,after Green,1957);2,Epistylis(E.gammari,after Precht,1935).Rhabdostyla sp.Bierhof&Roos,1977.Between the spines at the end of the telson on Gammarus tigrinus.Germany.Rhabdostyla sp.Weissman et al.,1993.On the copepod Acartia hudsonica. Genus Epistylis Ehrenberg,1832( g.2)E.anastatica(Linnaeus,1767)(cf.Kent,1881).Syn.:Vorticella anastatica L.,1767.On Entomostraca and freshwater plants.On cyclopoid copepods and Daphnia pulex(cf.Green,1974).E.astaci Nenninger,1948.Fresh water.On the gills of the decapod Astacusastacus(as A. uviatilis)(Germany).On A.leptodactylus(cf.Stiller,1971).On the gills of Austropotamobius torrentium(cf.Matthes&Guhl,1973).E.bimarginata Nenninger,1948.Fresh water.On the appendages of Astacusastacus(as A. uviatilis).Germany.E.branchiophila Perty,1852.Syn.:E.formosa Nenninger,1948.On theparasitic copepod Lernaea cyprinacea,in freshwater environments of South Africa(Van As&Viljoen,1984).E.breviramosa Stiller,1931.On the antennal lament of the cladoceran Daph-nia ke Balaton(Hungary).On the copepod Cyclops sp.,Czechoslovakia (Srámek-Husek,1948).On the cladocerans Bosmina longirostris and Alona af nis(cf.Green,1974).E.cambari Kellicott,1885.On the gills of the decapod Cambarus sp.(NE ofU.S.A.).On the maxillae of the cray sh Astacus leptodactylus(fresh water) (cf.Matthes&Guhl,1973).E.crassicollis Stein,1867.On freshwater Entomostraca and on the pleopodsand gills of cray sh.On the gills of Astacus astacus(as A. uviatilis),andCRUSTACEAN PROTOZOAN EPIBIONTS,I.PERITRICH CILIATES647 the maxillae,maxillipeds,and gills of A.leptodactylus,in Europe(Matthes& Guhl,1973).E.cyprinaceae Van As&Viljoen,1984.On the parasitic copepod Lernaea cyprinacea(fresh water,South Africa).E.daphniae Fauré-Fremiet,1905.On the cladoceran Daphnia sp.On Daphnia magna(cf.Nenninger,1948).On the copepod Boeckella triarticulata(New Zealand)(Xu&Burns,1990).On the cladoceran Moina macrocopa in an urban stream.E.diaptomi Fauré-Fremiet,1905.On the copepod Diaptomus sp.E.digitalis Ehrenberg,1838.On the copepod Cyclops sp.E.epibarnimiana Van As&Viljoen,1984.On the parasitic copepod Lernaea barnimiana(fresh water,South Africa).E.fugitans Kellicott,1887.On the cladoceran Sida crystallina.North America.E.gammari Precht,1935.On the antennae of the gammarid Gammarus sp. (Kiel channel).On the proximal part of the rst antenna and,less commonly, on the second antenna of Gammarus oceanicus and G.salinus.In the Baltic Sea and areas of Norway(Fenchel,1965).On the rst antenna of Gammarus tigrinus(cf.Stiller,1971).E.halophila Stiller,1942.On the cladocerans Daphnia longispina and D.pulex (Lake Cserepeser,Hungary).E.harpacticola Kahl,1933.On harpacticoid copepods in the Kiel channel. E.helenae Green,1957.On the cladocerans Daphnia pulex,D.magna,D.ob-tusa,D.longispina,D.curvirostris,Ceriodaphnia pulchella,C.reticulata, ticaudata,Moina macrocopa,M.micrura,Chydorus sphaericus,Simo-cephalus serrulatus,and S.vetulus(cf.Green,1957,1974).On Daphnia magna(cf.Nenninger,1948).On Ceriodaphnia reticulata and Simocephalus vetulus(cf.Matthes,1950).E.humilis Kellicott,1887.On the gammarid Gammarus sp.and other Ento-mostraca.custris Imhoff,1884.On the pelagic copepod Cyclops sp.On the buccal appendages of the branchiopod Lepidurus apus(freshwater areas near Vienna, Austria)(Foissner,1996).E.magna V an As&Viljoen,1984.On the parasitic copepod Lernaea cypri-nacea(fresh water,South Africa).E.niagarae Kellicott,1883.On the body surface of cray sh(Niagara River, U.S.A.).On the antennae and body of the European cray sh Astacus lep-todactylus,on Austropotamobius torrentium,and on Orconectes limosus(as Cambarus af nis)(cf.Matthes&Guhl,1973).On the surface of the copepod648G.FERNANDEZ-LEBORANS&M.L.TATO-PORTOEucyclops serrulatus,and on the cladocerans Daphnia pulex,D.rosea,Cerio-daphnia reticulata,and Scapholeberis mucronata(lakes of Colorado,U.S.A.) (Willey&Threlkeld,1993).E.nitocrae Precht,1935.On the third pereiopod of Gammarus tigrinus(cf.Bierhof&Roos,1977).E.nympharum Engelman,1862.On cladocerans(Nenninger,1948).On Cy-clops sp.(cf.Foissner&Schiffman,1974).On the branchiuran Dolops ra-narum(cf.Van As&Viljoen,1984).E.ovalis Biegel,1954.On the gnathopods of Gammarus tigrinus.On the thirdpereiopod of the gammarid Gammarus pulex,and on the spines at the end of the third uropod of Gammarus tigrinus(cf.Bierhof&Roos,1977).E.plicatilis Ehrenberg,1838.On the copepods Eucyclops agilis,Cyclopsvernalis,and C.bicuspidatus(Ashmore Lake,Illinois,U.S.A.)(Henebry& Ridgeway,1979).E.salina Stiller,1941.On the rst and second antennae,coxae,and gills of thegammarid Gammarus pulex(cf.Bierhof&Roos,1977).E.thienemanni Sommer,1951.On the gills of Gammarus tigrinus(cf.Bierhof&Roos,1977).E.zschokkei(Keiser,1921).Syn.:Opercularia zschokkei Keiser,1921.On thegnathopods of the gammarid Gammarus tigrinus and on other Entomostraca.On the cladoceran Acantholeberis curvirostris(cf.Nenninger,1948).Epistylis sp.Hutton,1964.On the decapod Penaeus duorarum(Florida,U.S.A.).Between the setae of the rst antenna of Gammarus tigrinus(cf.Bierhof& Roos,1977).Epistylis sp.Hutton,1964.On the decapod Ploeticus robustus(Daytona Beach, Florida,U.S.A.).Epistylis sp.Viljoen&Van As,1983.Two species on the thoracic appendages of a freshwater brachyuran,apparently erroneously identi ed as“Potamon sp.”(South Africa)[the genus Potamon does not occur in southern Africa].Epistylis sp.Pearse,1932.On the gills of the decapods Coenobita clypeatus, Geograpsus lividus,and Pachygrapsus transversus(Florida,U.S.A.).Epistylis sp.Hudson&Lester,1994.On the gills of the decapod Scylla serrata (Moreton Bay,Queensland,Australia).Epistylis sp.Turner et al.,1979.On the estuarine copepods Acartia tonsa andA.clausi(Escambia Bay,Florida,U.S.A.).Epistylis sp.Villarreal&Hutchings,1986.Fresh water.On the maxillipeds, pereiopods,and ventral portion of the abdomen of the decapod Cherax tenuimanus(Australia).CRUSTACEAN PROTOZOAN EPIBIONTS,I.PERITRICH CILIATES649 Family Lagenophryidae Bütschli,1889Genus Lagenophrys Stein,1852( g.3)L.aegleae Mouchet-Bennati,1932.Fresh water.On the branchial laments of the anomurans Aegla sp.,Aegla castro,and Aegla franca.Arroyo Miguelete, (Uruguay)and Parana River(Brazil).L.ampulla Stein,1851.Fresh water.On the gills of species of the genus Gammarus.L.andos(Jankowski,1986)(cf.Clamp,1991).Syn.:Circolagenophrys andos Jankowski,1986.Fresh water.On the decapod Parastacus chilensis(Chile).L.anticthos Clamp,1988.Fresh water.On the branchial laments of the decapods Parastacus pugnax,P.defossus,and P.saffordi(Chile,Brazil, Uruguay).L.aselli Plate,1886.On the branchial surface of the isopod Asellus aquaticus (Hamburg,Germany).L.awerinzewi Abonyi,1928.On the gills of the decapod Potamon uviatilis(as Telphusa uviatilis)(Africa).L.bipartita Stokes,1890.On the cladoceran Daphnia sp.(fresh water,U.S.A.).L.branchiarum Nie&Ho,1943.Fresh water.On the gills of the caridean shrimp Macrobrachium nipponense(as Palaemon nipponense)(Japan).L.callinectes Couch,1967.Marine and in estuaries.On the gills of the decapods Callinectes sapidus,C.bocourti,and C.maracaiboensis(Chesapeake Bay, Maryland,Virginia,and Gulf of Mexico).mensalis Swarczewsky,1930.Fresh water.On gammarids(Lake Baikal).L.darwini Kane,1965.On the branchial laments of the decapod Cherax quadricarinatus(stream near Darwin,Australia).L.dennisi Clamp,1987.Fresh water.On the decapods Orconectes illinoiensis, Cambarus bartonii bartonii,and C.chasmodactylus(North America).L.deserti Kane,1965.Fresh water.On the gills of the decapods Cherax tenuimanus and C.quinquecarinatus(SW rivers,Australia).L.diogenes(Jankowski,1986).Syns.:Circolagenophrys diogenes Jankowski, 1986,Lagenophrys incompta Clamp,1987.Fresh water.On the gills of the decapods Orconectes illinoiensis and Cambarus diogenes(Illinois,U.S.A.).L.discoidea Kellicott,1887(cf.Clamp,1990).Syns.:Lagenophrys labiata Wallengren,1900(a junior homonym of biata Stokes,1887(cf.Clamp, 1990));L.wallengreni Abonyi,1928;Circolagenophrys entocytheris Jankow-ski,1986.Fresh water.On ostracods.On the cray sh Cambarus sp.,C.chas-modactylus,C.bartonii bartonii,and Orconectes illinoiensis(Ontario,Canada and U.S.A.).650G.FERNANDEZ-LEBORANS&M.L.TATO-PORTOFigs.3-7.3,Lagenophrys(L.eupagurus,after Clamp,1989);4,Clistolagenophrys(C.primitiva, after Swarczewsky,1930);5,Setonophrys(munis,after Clamp,1991);6,Operculigera (O.asymmetrica,after Clamp,1991);7,Usconophrys(U.aperta,after Clamp,1991).L.dungogi Kane,1965.On the branchial laments of the decapod Euastacus sp.(stream near Dungog,Australia).L.engaei Kane,1965.On the branchial laments,basal areas of the gills, branchiostegite membrane and,more rarely,on the pleopods of the decapods Engaeus victoriensis and Austroastacus hemicirratulus(Victoria,Tasmania, and Melbourne,Australia).L.eupagurus Kellicott,1893(cf.Clamp,1989).Syns.:Lagenophrys lunatus Imamura,1940;Lagenophrys articularis Nie&Ho,1943.Marine,in estu-arine areas and fresh water.On the decapods Litopenaeus setiferus(as Pe-CRUSTACEAN PROTOZOAN EPIBIONTS,I.PERITRICH CILIATES651 naeus s.)(Penaeidea,Penaeidae),on the surface of the body,Litopenaeus van-namei(as Penaeus v.),on the surface of the body,Macrobrachium nipponense (Caridea,Palaemonidae)on antennae and pleopods,Macrobrachium ohione, on the surface of the middle of the pleura,Macrobrachium rosenbergii,on the gills,Palaemon paucidens(Caridea,Palaemonidae),Palaemonetes inter-medius(Caridea,Palaemonidae),Palaemonetes kadiakensis,Palaemonetes paludosus,Palaemonetes pugio,Palaemonetes varians,on the whole body, except on the gills,Palaemonetes vulgaris,Upogebia af nis(Thalassinidea, Upogebiidae),and Pagurus longicarpus(Anomura,Paguridae),on the gills (U.S.A.,Japan,Venezuela,Thailand).L.foxi Clamp,1987.Fresh water.On the gills of the gammarids Gammarus pseudolimnaeus,G.troglophilus,G.minus,and Gammarus sp.(Missouri, U.S.A.).L.in ata Swarczewsky,1930.On the distal areas of pleopods of the gammarid Gmelinoides fasciata(Lake Baikal).L.jacobi(Kane,1969).Syn.:Stylohedra jacobi Kane,1969.On freshwater decapods in Australia.L.johnsoni Clamp,1990.Syn.:Lagenophrys labiata Stokes,1887(partim). Fresh water.On the appendages and the surface of the carapace of the gammarids Gammarus fasciatus,G.daiberi,G.tigrinus,and Crangonyx gracilis(New Jersey,Michigan,and North Carolina,U.S.A.).biata Stokes,1887(cf.Clamp,1990).Fresh water.On the appendages and on the surface of the carapace of the gammarids Gammarus fasciatus, G.daiberi,G.tigrinus,and Cangronyx gracilis(New Jersey,Michigan,and North Carolina,U.S.A.).L.leniusculus(Jankowski,1986).Syns.:Circolagenophrys leniusculus Jan-kowski,1986;L.oregonensis Clamp,1987.Fresh water.On the carapace, gills,ventral surface of the abdomen,uropods,pereiopods,and pleopods of the decapod Pacifastacus leniusculus leniusculus,and on the gills of P.leniusculus trowbridgii and P.connectens(North America).L.lenticula(Kellicott,1885)(cf.Clamp,1991).Syns.:Stylohedra lenticula Kellicott,1885;S.lenticulata Kahl,1935;Lagenophrys lenticulata(Kahl, 1935)(cf.Thomsen,1945).Fresh water.Setae of the sixth and seventh pereiopods of the gammarids Hyalella azteca and H.curvispina(U.S.A., Canada,Mexico,and Uruguay).L.limnoria Clamp,1988.Syn.:Circolagenophrys circularis Jankowski,1986 (cf.Clamp,1991).On the isopod Limnoria lignorum.L.macrostoma Swarczewsky,1930.Fresh water.On gammarids(Lake Baikal). L.matthesi Schödel,1983.On the maxillipeds of the gammarids Gammarus pulex and Carinogammarus roeselii.652G.FERNANDEZ-LEBORANS&M.L.TATO-PORTOL.metopauliadis Corliss&Brough,1965.Fresh water.On the gills of the brachyuran Metopaulias depressus(endemic on Jamaica).L.monolistrae Stammer,1935.On the pleopods of the isopod Monolistra sp.L.nassa Stein,1852.Fresh water.On the pleopods of the gammarid Gammarus pulex.L.oblonga Swarczewsky,1930.On the antennae of the gammarid Gammarus hyacinthinus(Lake Baikal).L.orchestiae Abonyi,1928.On the amphipod Orchestia cavimana(Lake Balaton,Hungary).L.ornata Swarczewsky,1930.Fresh water.On ke Baikal.L.ovalis Swarczewsky,1930.Fresh water.On the thoracic appendages of ke Baikal.L.parva Swarczewsky,1930.On ke Baikal.L.patina Stokes,1887(cf.Clamp,1990).Syn.:Lagenophrys labiata Stokes, 1887(cf.Shomay,1955).(Corliss&Brough,1965;Clamp,1973).Fresh water.On the pereiopods and gills of the gammarids Gammarus sp.and Hyalella azteca.American continent.L.rugosa Kane,1965.Fresh water.On the gills of the decapod Geocharax falcata(Victoria,Australia).L.similis Swarczewsky,1930.On ke Baikal.L.simplex Swarczewsky,1930.On ke Baikal.L.solida Swarczewsky,1930.On ke Baikal.L.stammeri Lust,1950.On ostracods.Germany.(Lust,1950a).L.stokesi Swarczewsky,1930.On ke Baikal.L.stygia Clamp,1990.Syn.:Lagenophrys labiata Stokes,1887(cf.Jakschik, 1967).Subterranean water.On the gills of the cave-dwelling amphipod Bactrurus mucronatus(Illinois,U.S.A.).L.tattersalli Willis,1942.On European copepods.L.turneri Kane,1969.On freshwater decapods in Australia.L.vaginicola Stein,1852.Syn.:Lagenophrys obovata Stokes,1887.On the genital setae and thoracopods of the copepods Cyclops miniatus and Cantho-camptus sp.L.verecunda Felgenhauer,1982.On the decapod Palaemonetes kadiakensis (Illinois,U.S.A.).L.willisi Kane,1965.Fresh water.On the gills of the decapods Cherax destructor,C.albidus,and C.rotundus(Melbourne,New South Wales(e.g., Newcastle),and NW Australia).Genus Clistolagenophrys Clamp,1991( g.4)C.primitiva(Swarczewsky,1930)(cf.Clamp,1991).Syn.:Lagenophrys primi-tiva Swarczewsky,1930.On pereiopods and pleopods of the gammarid Pallasea cancellus(Lake Baikal).Genus Setonophrys Jankowski,1986(cf.Clamp,1991)( g.5)S.bispinosa(Kane,1965)(cf.Clamp,1991).Syn.:Lagenophrys bispinosa Kane,1965.On pereiopods of the decapod Cherax rotundus setosus.Stream near Newcastle(N.S.W.,Australia).munis(Kane,1965)(cf.Clamp,1991).Syn.:Lagenophrys communis Kane,1965.On the body surface(telson,pleopods,pereiopods,carapace...) of the decapod Cherax destructor.On the gills of the decapods C.rotundus,C.albidus,C.quadricarinatus,Euastacus armatus,and Engaeus marmoratus(Victoria,Melbourne,and Tasmania,Australia).S.lingulata(Kane,1965)(cf.Clamp,1991).Syn.:Lagenophrys lingulata Kane,1965.On the branchial laments and branchiostegite membrane of the decapods Cherax destructor, C.albidus,and C.rotundus(Victoria, Melbourne,and coastal and central areas of Australia).S.nivalis(Kane,1969)(cf.Clamp,1991).Syn.:Lagenophrys nivalis Kane, 1969.On freshwater decapods in Australia.S.occlusa(Kane,1965)(cf.Clamp,1991).Syn.:Lagenophrys occlusa Kane, 1965.On the anterior zone of the branchial cavity of the decapods Cherax destructor,C.albidus,and C.rotundus(Victoria and New South Wales, Australia).S.seticola(Kane,1965)(cf.Clamp,1991).Syn.:Lagenophrys seticola Kane, 1965.On the setae of the decapods Engaeus fultoni and Geocharax falcata (Victoria,Melbourne,and Templestowe,Australia).S.spinosa(Kane,1965)(cf.Clamp,1991).Syn.:Lagenophrys spinosa Kane, 1965.On the pleopods,carapace,and telson of the decapod Cherax destructor (Victoria,Melbourne,and Heathcote,Australia).S.tricorniculata Clamp,1991.On the pleopods of the decapod Geocharax falcata(Victoria,Grampian Mountains,and Wannon River,Australia). Genus Operculigera Kane,1969( g.6)O.asymmetrica Clamp,1991.On the base of the gills of the freshwater decapods Parastacus pugnax and Samastacus spinifrons(Concepción and Talcahuano,Chile).O.insolita Clamp,1991.On the base of the gills of the freshwater decapod Parastacus pugnax(Concepción,Talcahuano,Malleco,and Puren,Chile).O.montanea Kane,1969.On the freshwater decapod Colubotelson sp.(Aus-tralia).O.obstipa Clamp,1991.Pleopods of the isopod Metaphreatoicus australis (New South Wales,Australia).O.parastacis Jankowski,1986.On the base of the gills of the decapod Parastacus nicoleti(Isla Teja,Valdivia,Chile).O.seticola Clamp,1991.On the setae at the base of gills of the decapod Parastacus pugnax(Concepción,Chile).O.striata Jankowski,1986.On the decapod Parastacus chilensis.Chile.O.taura Clamp,1991.On the branchial laments of the freshwater decapod Parastacus pugnax(Concepción,Malleco,and Puren,Chile).O.velata Jankowski,1986.On the gills of the anomuran Aegla laevis.Chile.O.zeenahensis Kane,1969.On freshwater decapods in Australia.Family Usconophryidae Clamp,1991Genus Usconophrys Jankowski,1985(cf.Clamp,1991)( g.7)U.aperta(Plate,1889)(cf.Clamp,1991).Syns.:Lagenophrys aperta Plate, 1889;Usconophrys dauricus Jankowski,1986.On the gills and pleopods of the isopod Asellus aquaticus(Marburg and Hessen,Germany;North Carolina, U.S.A.;Brittany,Finisterre,Plougarneau,Pont-Menou,and Douron River, France).U.rotunda(Precht,1935)(cf.Clamp,1991).Syn.:Lagenophrys rotunda Precht,1935.On ostracods.Germany.Family Operculariidae Fauré-Fremiet,1979(in Corliss,1979)Genus Opercularia Stein,1854( g.8)O.allensi Stokes,1887.Syn.:O.ramosa Stokes,1887.On several living and inert substrata.On the body of the cray sh Astacus leptodactylus(cf.Matthes &Guhl,1973).O.asellicola Kahl,1935.On the isopod Asellus sp.Germany.O.coarctata Claparède&Lachmann,1858.On crabs(Buck,1961).O.crustaceorum Biegel,1954.On the gills of the cray sh Astacus astacus(asA. uviatilis).On the maxillae,maxillipeds,and pleopods of Austropotamo-bius torrentium(cf.Matthes&Guhl,1973).O.cylindrata Wrzesniowski,1807.On the copepod Cyclops sp.O.gammari Fauré-Fremiet,1905.Pereiopods of the gammarid amphipod Gammarus sp.O.lichtensteini Stein,1868.On various crabs and molluscs.O.nutans Ehrenberg,1838.Syn.:O.microstoma Stein,1854.On Entomostraca.On the cladoceran Alona af nis(cf.Matthes,1950).On the maxillipeds of the European cray sh Astacus leptodactylus(cf.Matthes&Guhl,1973).O.protecta Penard,1922.On the setae of pereiopods of the gammarid amphi-pod Gammarus pulex.O.reichelei Matthes&Guhl,1973.Found exclusively on the maxillipeds of the cray sh Astacus leptodactylus.O.stenostoma Stein,1868.On the isopod Asellus aquaticus.Genus Orbopercularia Lust,1950(cf.Lust,1950b)( g.9)O.astacicola(Matthes,1950)(cf.Matthes&Guhl,1973).Syn.:Opercularia astacicola Matthes,1950.Maxillipeds and pleopods of the cray sh Aus-tropotamobius torrentium.Genus Propyxidium Corliss,1979( g.10)P.aselli Penard,1922.On the isopod Asellus sp.P.asymmetrica Matthes&Guhl,1973.On the European cray sh Astacus astacus(as A. uviatilis).P.bosminae Kahl,1935.On the cladoceran Bosmina sp.P.canthocampti Penard,1922.On the pereiopods of the harpacticoid copepod Canthocamptus sp.Fresh water.P.cothurnioide Kent,1880.On the ostracod Cypris sp.P.hebes Kellicott,1888.On the pereiopods of the isopod Asellus aquaticus.P.henneguyi(Fauré-Fremiet,1905)(cf.Kahl,1935).Syn.:Opercularia hen-neguyi Fauré-Fremiet,1905.On the rst abdominal segment of the copepod Cyclops sp.Genus Ballodora Dogiel&Furssenko,1921( g.11)B.dimorpha Dogiel&Furssenko,1921.On Porcellio sp.and other terrestrialisopods.Genus Nuechterleinella Matthes,1990( g.12)N.corneliae Matthes,1990.On the ostracod Cypria ophthalmica.Genus Bezedniella Stoukal&Matis,1994( g.13)B.prima Stoukal&Matis,1994.Fresh water.On the ostracod Cypria sp.(Slovakia).Figs.8-14.8,Opercularia(O.nutans,after Foissner et al.,1992);9,Orbopercularia(O.astacicola, after Matthes&Guhl,1973);10,Propyxidium(P.canthocampti,after Penard,1922);11,Ballodora (B.dimorpha,after Dogiel&Furssenko,1921);12,Nuechterleinella(N.corneliae,after Matthes, 1990);13,Bezedniella(B.prima,after Stoukal&Matis,1994);14,Rovinjella(R.spheromae,afterMatthes,1972).Family Rovinjellidae Matthes,1972Genus Rovinjella Matthes,1972( g.14)R.spheromae Matthes,1972.On the marine isopod Sphaeroma serratum. Family Scyphidiidae Kahl,1933Genus Scyphidia Dujardin,1841( g.15)Scyphidia sp.Henebry&Ridgeway,1979.On the cladocerans Scapholeberis kingi,Alona costata,and Pleuroxus denticulatus(Ashmore Lake,Illinois, U.S.A.).Family Vaginicolidae De Fromentel,1874Genus Platycola Kent,1881( g.16)P.baikalica(Swarczewsky,1930).Syn.:Vaginicola baicalica Swarczewsky, 1930.Fresh water.On the gills of the gammarids Brandtia lata,Pallasea grubei,and Echinogammarus fuscus(Lake Baikal).P.callistoma Hadzi,1940.Fresh water.On the cave-dwelling isopod Microlis-tra spinosissima(former Yugoslavia).P.circularis Dons,1940.Marine.On the uropods of the isopod Limnoria sp.P.decumbens(Ehrenberg,1830).Syns.:Vaginicola decumbens Ehrenberg, 1830;Platycola ampulla De Fromentel,1874;P.regularis De Fromentel, 1874;P.striata De Fromentel,1874;P.truncata De Fromentel,1874;P.longicollis Kent,1882;P.intermedia Kahl,1935;P.re exa Kahl,1935;P.amphora Swarcezwsky,1930;P.amphoroides Sommer,1951.Fresh water.On several vegetable and animal substrata.On the gills of the gammarid Brachiuropus sp.(Lake Baikal)(Swarczewsky,1930).geniformis Hadzi,1940.Fresh water.On the cave-dwelling isopod Micro-listra spinosissima(former Yugoslavia).P.pala Swarczewsky,1930.Syn.:Vaginicola pala Swarczewsky,1930.On the gills of the gammarid Palicarinus puzyllii(as Parapallesa pazill)(Lake Baikal).Genus Cothurnia Ehrenberg,1831(cf.Claparède&Lachmann,1858)( g.17)C.angusta Kahl,1933.Brackish or fresh water.On ostracods(Kiel,Germany).C.anomala Stiller,1951.Fresh water.On the amphipod Corophium curvispi-num(Lake Balaton,Hungary).C.antarctica(Daday,1911)(cf.Warren&Paynter,1991).Syn.:Cothurniopsisantarctica Daday,1911.Marine.Epibiont on the ostracod Philomedes lae-vipes(Antarctic areas).C.astaci Stein,1854.Fresh water.On the pleopods and gills of cray sh.On the maxillae,maxillipeds,and pleopods of the cray sh Astacus astacus。

标准三联方案和序贯方案在我国幽门螺杆菌患者中的多中心、随机对照研究

目录
Zhou L, Zhang J, Chen M, Hou X, Li Z, Song Z, He L, Lin S. A comparative study of sequential therapy and standard triple therapy for Helicobacter pylori infection: a randomized multicenter trial. Am J Gastroenterol 2014; 109: 535-541.
目录
意义
1.
2.
进一步深化了我们对序贯方案的认识；进一步提示我们，Hp感染的根除治疗应该根据不同人群和Hp菌株的自身特点，有针对性地选择根除方案，才能取得持久的良好疗效，我国Hp感染的根除治疗不能完全照搬国外的指南性意见，而应该进一步积极探索适合我国Hp感染患者的根除方案和策略。
目录
周丽雅,宋志强.序贯方案和标准三联方案在我国幽门螺杆菌感染初治患者中的多中心、随机对照研究[J].中华内科杂志,2014,53(7):576.
目录
Zullo A, Rinaldi V, Winn S，et al．A new highly effective short term therapy schedule for Helicobacter pylori eradication．Aliment Pharmacol Ther 2000，14: 715-718．
目录
研究背景

随着抗菌药物耐药率的不断升高，Hp感染标准三联方案的根除疗效明显下降↓↓↓，已不适合作为经验性一线根除治疗方案，亟需疗效和安全性好的新方案。尽管国外有研究显示序贯方案的根除率和安全性均较好，但尚缺乏在我国Hp感染初治患者中的大样本临床验证研究。

质子衰变(Proton+decay)

质子衰变（Proton decay）质子衰变(Proton decay)From the scale of the universe, there should be half of the matter, antimatter in half, two are equal in number. He said in a speech in Nobel, the earth or the solar system, and is the dominant electron proton in the number "is really a chance". He said: "very likely, some of the planet, is not the case. The planet is mainly composed of positron and proton negative. In fact, may each star in each half. These two quasars are identical spectra. In astronomy the existing methods cannot distinguish between the two types of stars." Indeed, the symmetry of the universe is natural and harmonious, consistent with the aesthetic criterion.However, physics and cosmology are speculative science is not purely theoretical, they must first respect and based on certain facts. More and more facts have shown that the cosmic particle content is far greater than the anti particle content, the two is asymmetric. Dirac speculation against the observed facts, which is not correct.Now that the observed baryon number density nB of the universe is10-6 / cm 3, namely the standard Big Bang cosmology, cosmic ray observation today is 1010 light-years (1028 cm), so in the universe and the total baryon Antibaryon difference is 1078. In order to push back very early to the big bang, when t=10-35 seconds, according to thestandard model, then the universe line is about 1 cm, so that the baryons and antibaryons number density differenceOn the other hand, the temperature of T=1028K in t=10-35 seconds, and by the standard model to the total particle number density NB = 1087 / cm 3. (2)So, by (1), (2) available in the early universe baryon asymmetry is By (3) the observation in the universe today so many baryons is required in the early asymmetry and baryon content in the universe: At that time every 109 baryon (109-1) with about a antibaryon. Obviously, this asymmetry is very small. But why is this asymmetry? This is the big bang cosmology the question must be answered.Baryon number three, the origin of CosmologyThe basic idea of the big bang cosmology believes that the processof everything in the universe has its generation, the phenomena of the universe the existing complex and asymmetric, is the evolution of the universe from the original simple, symmetric and asymmetric type (4), also from the original symmetrical universe (i.e. baryons and anti baryon number density is equal) evolved. By symmetry evolution to the asymmetry, it produces a "baryon origin".In 1967 the Soviet physicist Saha Love (Sakharov) suggested that asymmetric baryon number requires three elements from the baryon Antibaryon symmetric - the evolution of the universe:1. change of baryon number B function;2.C and CP are not conserved;3. there is a deviation from the heat balance of the.Here is the basic premise to first, if there is change of baryon number B, there are inevitable baryon number conservation process. "Baryon number conservation" B conservation,It is in the particle change process, baryon anti baryon number is constant. The proton is the lightest baryons, if it is unstable, it can decay into lighter particles is not of the baryons and it willinevitably destroy B conservation. So, if found the proton decay, directly proved that B is not always conserved.There is no B conservation process, for solving the problem of the origin of the baryon number is only a necessary condition but not sufficient condition. Because, even if the proton is not stable, but if the antiproton is unstable, and the decay rate is the same, it still cannot evolve from symmetric to asymmetric positive and negative state and proton proton. Therefore, another necessary condition to solve the problem of the origin of the baryon number is the existence of asymmetry between positive and negative particles process, this process is called C or CP failure process failure process. Here, P represents the space inversion, which is reversible; C represents the charge conjugation, namely particle and anti particle exchange; CP conserved meaning: will swap around at the same time, particles and antiparticles swap, the laws of physics remain unchanged. As a system of baryons andantibaryons in entropy is equal to the number of maximum deviation, so the heat balance is generated when the microscopic interactionasymmetry is necessary. Therefore, once these processes deviate from the heat balance, you can make a first symmetrical universe into a baryon Antibaryon asymmetry than. This is the second, third elements proposed by Saha Love.CP process is not conserved, early in 1964 by the American physicist Cronin (Cronin), Fitch (Fitch) et al found (the discovery that two of them were awarded the 1980 Nobel prize in physics). This is thelongevity of the hit K1 meson decay. The following two kinds of meson decay process:Because the anti particle of K1 is its own, so, if CP is conserved. These two kinds ofDecay of opportunity must be equal. Proof of successful experiments of Cronin et al., K1 is moreThe CP is a real effect. Cronin in his speech, Nobel said: "this effect tells us, between matter and antimatter asymmetry basic."Four, grand unification theory and the evolution of the universe There is a direct link between the asymmetry? In our daily experience why proton is stable? This series of questions, the big bang cosmology does not provide people with more knowledge. What should I do? In modern science increasingly integrated today, people already broke through the barriers between thetraditional professional disciplines, in between the fields of exploration, mining and cultivation. People of the research results ofthe grand unified theory "used in the evolution of the universe, which opens up a new prospect for solving the" baryon number origin ".The grand unified theory, is the strong interaction is based on a unified unified in weak, make a unified description in theory. A unified model is currently the most popular SU (5), it will be quarks and leptons together which can be transformed into each other, which is not according to the conservation of baryon number. In this theory, in addition to transfer the electromagnetic force, the weak interaction of photon transfer boson gluon transfer, strong external,Also requires a new role leading to transfer the baryon number isnot conserved. This new function is called super weak, its transmission called "X particle". Because the X particles can cause B damage and X conservation, then there may be particle decay below:A class may decay as follows:These processes exist, will lead to proton decay.The proton is composed of u, u, d three quarks. Through the mediumof X particles, can make two quarks and anti quarks into leptons, quarks and the anti proton in third quarks meson, and proton decay to lepton and meson. The specific reaction sequence following instantiation: By the interaction of X particle coupling is very weak, and the quality of X is very large, so the proton extremely long life. The theory is expected, the quality of X is about 1015GeV (equivalent to 1015 times the mass of the proton), the average life expectancy of proton decay is about 1031. That is to say, that the grand unifiedtheory, only when the energy is as high as 1015GeV (G=109), B of the process will play a significant role. At present, the largest high-energy accelerator of only a few hundred GeV, so for B conservation process in the laboratory is difficult to achieve. What places have such high energy? People naturally think of the big bang universe.Now that the big bang cosmology, the universe is about 15 billion years ago, from the beginning of the big bang, after the explosion of material in homogeneous and isotropic dramatic expansion from theinfinite high temperature cooling down. This theory, 2.73K background radiation and space helium abundance observed facts support. If the extrapolation of the standard big bang model to zero time until close to the explosion, then the total energy of all the space should be above 1015GeV. This provides the evolution mechanism of the grand unified theory for the origin of the baryon number, and after the big bang of the very early universe created conditions for the baryon origin, the combination of the two, can naturally explain the baryon number asymmetry:In the age of the universe is less than 10-35 seconds when the temperature is higher than 1028K, corresponding to the thermal motion of particles in the universe, but because of the medium in thermal equilibrium, so the baryons and antibaryons number density is equal to annihilation or decay and disappear. If thisis the destruction of the CP decay, X particle decay results will lead to theoretical predictions, then the asymmetry will be betweenparticle and anti particle in 10-35 seconds nB ratio) is 10-9, then the total number of baryons and antibaryons difference will not change, but the density difference is not, stay composed of excess baryon Antibaryon universe, and then completely disappeared. This is the people today to see the scene.The unified theory of the evolution of the universe and particle harmoniously combined, draw a reasonable and natural evolution image, make people see the solution of the problem of the origin of baryon number of the dawn, which inspires many people seriously adopt a unified concept, in-depth study of the evolution problem of various largeunified model and universal input. In 1981, the National Science Foundation for a new research at the University of California Shengbabala branch of theoretical physics research,Is inviting the world working on similar problems of collective research scholars, six months to a year, expect them to work together, than they independently studied more fruitful results. In 1, the second half of June, they focus on the close relation between cosmology and particle physics, the research about the early universe, has made a lot of achievements. Now, although the description standard scheme of the baryon asymmetry generated has been widely accepted but this model still exist some basic uncertainty. Do not determine the thermal equilibrium hypothesis relates to as initial conditions. It was pointed out that if the universe is not in thermal equilibrium, without weighing the resulting level maybe different. Another uncertain place is the magnitude and type of CP damage. In 1980 Cronin Nobel said in a speech: "we've seen CP today is" legacy fossil "destroy the speculation of the early examples of the universe, this problem is still not answered....... We also know enough damage to CP "," we need to know the basic theory of CP damage, we need to know how reliable the CP damage characteristics of extrapolation to superhigh energy." Has almost become the conclusion. Someone made a decision to baryon asymmetry CP damage and the neutron electric dipole moment and not with the K meson system associated model (the neutron electric dipole moment is another possible form of CP damage). It isstill exploring. In conclusion, considerable progress in the theory of the origin of the baryon number, there are also some basic problems to be solved.Five, explore the proton decay experimentPractice is the criterion for testing truth. Baryon number origin must await further observation, to determine its reliability. To explore the proton decay experiment is feasible under the current conditions of the observation project.To detect the proton decay from the experiment is very difficult. Because of the proton decay examples of extremely long life, rarely, plus the product after the decay is not easy to detect and identify such experiments is not easy. All the experiments must meet the following conditions: first, there must be enough observation material, assuming that the proton lifetime for 1031, when we watch the pool of 4000 tonsof water (containing about 2.5 x 1033 protons and neutrons), every month can expectto see 20 examples of decay. Excluding other effects can be observed only about half. Therefore, there must be a lot of material monitoring. Neutron (except H2, all substances containing nearly half. The neutronis composed of quarks, also due to the transfer of a X quark particle decay. In all the "proton decay experiment, neutron decay is also included in this). Second, must eliminate interference of cosmic ray. The experiment must be in deep underground or under the sea, to prevent the use of cosmic rays or soil water, but in a high energy cosmic ray muon and neutrino, muon penetration is very strong, there is still a part of the deep underground, and neutrinos can almost penetrate the earth without attenuation. According to the unified theory, proton decay most often the possible ways of P to PI 0+e+. PI 0 will immediately decay into two photons. We can from the measuring device within one point suddenly released a e+ and two gammaAs the +n0+e+ process, we can distinguish. So,Third, to have a signal to identify the authenticity of the track and energy characteristics of proton decay products of the device.The first experiment is Reines and Goldhaber conducted in 1954. They used 50 kilograms of scintillator, the total number of protons and neutrons is about 3 * 1028. If there is a proton decay of e+ and PI 0, then each particle energy should be close to 500MeV, of which 0 PI quickly decays for high-energy gamma photon. The motion of the energeticparticles in the scintillator will make the scintillation luminescence. Using photomultiplier tube to accept these optical signals can calculate the trajectory and energy of energetic particles, whichcan distinguish the interference and the cosmic ray proton decay. In order to reduce the influence of cosmic rays, experiments were carried out in a 30 meter deep underground chamber. The test run for a few hours, a few times per second flash, but the analysis results that these flash are false signal caused by cosmic rays, not a proton decay event found. It can be concluded that the proton lifetime at least more than 1022.Compared with several groups of experiments currently underway, the first experiment in 1954, the scale is too small. At present, the proton decay experiment can be roughly divided into two categories:A kind of water observation material. High-energy charged particles moving in water, as long as the speed is greater than the speed of light will shine (water Cherenkov effect). In very pure water, light propagation distance of up to tens of meters, the range is much longer than the particle, so you can use less of the instrument to monitor more material. The largest experiment was carried out in a 600 meter deepsalt mine in the American state of Ohio. The research group from the University of California at Erwin University of Michigan Brook, Brookhaven National Laboratory and some other universities in the United States, Britain, Poland, the leader is Reines. The detector center is 17 x 18 x six 23m3 pure water, surrounded by 2048 rectangularphotomultiplier tube, each diameter is 12.5cm, Cerenkov radiation andtwo photon detection based on e+ through pure water, after 130 days of observation, were detected in a decay event. In 1983 they announced that the lower limit of theaverage life expectancy for proton decayP > 6.5 * 1031Another type of iron or concrete material for monitoring. Iron isthe major, so the number of nuclear as much iron in small area. But the iron is opaque, no Cherenkov effect can be used, only the direct detection of secondary particles produced by decay. Because of these particles in the range of iron in only a few centimeters, therefore, experimental device must be made a layer of iron, a layer of white folded detector. The unit weight of material in this device, detector and electronic system of a class of more than before, so this kind of device is generally more than 100 tons. A typical experiment is by University of Tokyo of Japan and India in collaboration with scientists in India Kolar gold more than 2300 meters deep underground. The summer of 1982, the group announced that found three proton decay examples, and the proton lifetime=7 * 1030.And the European Group, they conducted a study in Italy, the French Alps peak Blanc border tunnel. In 1983, the European Group also claimed that observed a decay event.The most simple SU (5) predicted that the grand unified theory, the average life expectancy of proton decay is not greater than 2.5 x in1031. To 1983, the experimental data of India gold group in support of SU (5) model, but the "salt" group and SU (5) the result is contrary. It is generally believed that from the experimental scale, observation method and the statisticalprecision of view, the United States "salt" experiments are credible, and "gold" the rough, the result is not convincing.According to reports, a meeting of 1984 yuan at the beginning of the month in the United States held in Utah, India, United States of Ohio, Japan, Switzerland and the United States, Utah, a total of five experimental groups, published experimental data about proton decay. In the experimental group to a mine in Japan Kamioka in comparison to announce with certainty, they found two cases of proton decay. Indiagold group reported they found a new instance, which they thought might be the proton decay event increased to four. However, Ohio's "salt"group or negative attitude. They reported that 170 decay phenomenon was recorded in the work of the CPC in 200 days, but all these phenomena are due to false signal caused by the neutrino. They concluded that the average life expectancy of the proton is greater than 2 * in 1032, therefore, the proton can decay, is still a mystery. However, can be interpreted as the case has increased in proton decay.The overall trend of six, baryon origin and ScienceThe origin of the baryon number is a frontier topic in particle physics and cosmology. Through the collaborative efforts of physicists and cosmologists, has put forward a reasonable scheme of baryon numberorigin. The first people hope that through the proton decay experiments to achieve a breakthrough. From the experimental results of 1984 several proton decay study group, people have seen "chaos". Although the unsolved problems are also many, the road is tortuous, but the pace is accelerating, which is no doubt. People see, in the study of this issue, the process of exploring the interdisciplinarypenetration of how important it is to explore the origin of the baryon number and make full use of particle physics and cosmology of the two disciplines and methods, this is between the basic theory of mutual integration, mutual coordination and transplantation and research methods the research method, which is a vivid manifestation of scienceis moving towards integration.The motion of matter form is not only diverse and unified. Thesubject also has differences and connections, mutual transition and transformation. When the study of the objective phenomenon of different disciplines is more thorough and meticulous, the more feel theconnection between all things and phenomena more closely. The particle and the universe are the two extremes of the physical world, in particle physics and cosmology of the two seems to be totally different fieldsbut there is a convergence point, it is the early universe. At that time, the medium is super hot gas composed of a large number of high-energy particles, and high-energy particle law became the basis of the overall behavior of the domination of the universe. At the confluence of the big bang model, a unified model of particle physics and cosmology of themutual integration, thereby creating a new scheme of baryon number origin, it not only helps people understand the evolution of the universe,But also can help people determine what elements of the particle physics theory is reasonable.In particle physics, symmetry method is a very importantresearch method. People can judge according to the symmetry of a process can occur. It also can not understand the specific form of interaction, according to the principle of symmetry of phenomenological particles occur between certain connections, so as to facilitate the systematic study of them. Symmetry also determines the lifetime of the particle. Because the particle decay is caused by the interaction of the strong interaction, particle decays faster, then the shorter the life.It is the symmetry method plays an important role in particle physics, Dirac put it as the "essence" of new methods of physics theory, and Heisenberg praised the symmetry reflects the spirit of the contemporary era of natural science". The symmetry method transplanted in cosmology, the emphasis is the research on asymmetry of things. From the nature of matter over antimatter in the observation of the facts, how to study from the baryon Antibaryon symmetric universe evolved into the baryon asymmetry of the universe. Which nature should be the existence of a process of baryon number is not conserved and CP symmetry, put forward the new thinking, not only prompted people to review some of the law of conservation of particle physics in the applicable scope and thesymmetry breaking mechanism, to further promote the development of physics, but also in the way of thinking to remind people: universal and effective not only should pay attention to the symmetry method, should also pay attention to the relativity and its limitations, should not be absolute symmetry, and should be dialectically integrated.The mutual infiltration and combination between disciplines, and even changing the research means. Always large accelerator is a basic tool for particle physicists. The basic tools of cosmologists has always been a large telescope. Now, theparticle physicists to left over from the big bang singularity particle bulk material search, helium and deuterium abundancedistribution of galaxies, cosmic microwave background, the structure and the detection of solar neutrino experiments are concerned. But cosmologists on mountains of cosmic ray observation, accelerator and reactor experiments, fractional charge detection, magnetic monopole search and other interested. The proton decay deep underground mine in the experiment, it is their common concern target. In short, the detection range of particle physics laboratory is extended to the deep, deep into the earth; cosmology by deep space and deep underground into the laboratory, research methods of two disciplines closely, are heading towards the same goal of advancing. (Wu Weiping)。

某医院质子泵抑制剂注射剂应用分析

· 351 ·质子泵抑制剂（proton pump inhibitors, PPIs ）是苯并咪唑类衍生物，作用于H +-K +-ATP 酶，能抑制基础胃酸的分泌及组胺、进食等多种刺激引起的酸分泌，其作用机制独特，特异性高，作用强大且持续时间长。

随着PPIs 的广泛应用，一些不合理用药现象日益凸显。

Ntaios 等[1]的研究结果显示希腊第三医院81.2%的患者无恰当适应证使用PPIs 。

Nasser 等[2]对286名使用奥美拉唑针的非危重患者的调查发现，88%的患者以预防应激性溃疡为目的，其中，仅17%的患者符合应激性溃疡预防用药指征，14%符合预防非甾体类抗炎药相关性溃疡指征，其余的69%无适应证用药。

Slattery 等[3]对101名使用PPIs 注射剂患者的调查结果显示仅6名患者有适应证。

目前我国有关某医院质子泵抑制剂注射剂应用分析唐　琪1,2，刘　妮1，尹　桃1（1.中南大学湘雅医院药剂科，湖南长沙 410008；2. 第二炮兵总医院药学部，北京 100088）[摘要] 目的：了解某医院质子泵抑制剂注射剂的使用现状。

方法：以某三甲综合性医院2010年住院病人为研究对象，对期间至少使用过1次质子泵抑制剂注射剂的住院患者经简单随机抽样进行回顾性调查，评价质子泵抑制剂注射剂使用的合理性。

结果：共调查病例1920例，仅9.9%（190/1920）的病例合理使用质子泵抑制剂注射剂。

不合理使用主要表现为用药指征不合理，占76.3%（1465/1920）。

91.4%（1755/1920）的病例以预防性用药为主，而以预防应激性溃疡为目的的病例占50.3%（967/1920）。

结论：应建立质子泵抑制剂的合理用药指南，加强用药干预，以改善质子泵抑制剂的不合理使用现状。

[关键词]　质子泵抑制剂；合理用药；预防性用药；用药指征[中图分类号] R975；R969.3 [文献标识码] A [文章编号] 1672 – 8157(2012)06 – 0351 – 03Analysis on the use of intravenous proton pump inhibitorsTANG Qi 1,2, LIU Ni 1, YIN Tao 1(1. Department of Pharmacy, Xiangya Hospital Central South University, Changsha 410008, China; 2.Pharmaceutical Department, The Second Artillery General Hospital, Beijing 100088, China )[ABSTRACT] Objective: To investigate the current application of intravenous proton pump inhibitors in the hospital. Methods:The medical records of patients using intravenous proton pump inhibitors at least once were chosen by simple random sampling for retrospective analysis on the rationality of prescribing intravenous proton pump inhibitors in inpatients of one comprehensive hospital in 2010. Results: In all of 1920 cases, only 9.9% (190/1920) of patients used intravenous proton pump inhibitors appropriately. The main manifestation of inappropriate use of intravenous proton pump inhibitors was improper indication, which accounted for 76.3% (1465/1920). 91.4% (1755/1920) of cases used proton pump inhibitors for prophylaxis, and 50.3% (967/1920) used for stress ulcer prophylaxis. Conclusion: It is suggested to establish guidelines on rational use of proton pump inhibitors and enhance medication interventional measures, in order to change the situation of inappropriate utilization.[KEY WORDS]　Proton pump inhibitor; Rational drug use; Prophylactic use of drug; Drug indicationPPIs 的研究大多以药物的金额、限定日剂量和用药频率等为指标[4-7]，反映药物使用情况及发展趋势。

高中英语第二部分 VOA慢速英语《美国万花筒》第20课(文本)素材

高中英语第二部分 VOA慢速英语《美国万花筒》第20课（文本）素材英语翻议讲解：1.abolitionist n.废除主义者,废奴主义者2.arsenal n.兵工厂,军械库,武器，军火库3.capture vt.抓取,获得,迷住例句：A large reward is offered for the capture of the criminals. 巨额悬赏捉拿这些罪犯。

The novel captured the imagination of thousands of readers. 这部小说引起了千万读者的想象。

4.sustainable adj.(对自然资源和能源的利用)不破坏生态平衡的, 合理利用的可持续的例句：Water Resource Protection and Sustainable Utilization 水资源保护与可持续利用。

1.To some people this building is the scene of a crime, where a murderer and a traitor was captured and brought to justice.bring to justice使归案受审例句：The police must do all they can to bring the criminals to justice. 警方必须尽力把罪犯送交法庭审判。

2.She is using her fame as a race car driver to bring environmental issues to the attention of millions of racing fans.bring to the attention of引起某人的注意例句：That way, you can bring a pattern of behavior to management's attention. 这样你就可以提请公司主管注意你老板的不当行为。

Antiprotonic hydrogen in static electric field

a rXiv:n ucl-t h /5132v112Ja n25Antiprotonic hydrogen in static electric ﬁeld G.Ya.Korenman and S.N.Yudin Skobeltsyn Institute of Nuclear Physics,Moscow State University,Moscow,Russia e-mail:korenman@anna19.sinp.msu.ru Abstract Eﬀects of the static electric ﬁeld on the splitting and annihilation widths of the levels of antiprotonic hydrogen with a large principal quantum number (n =30)are studied.Non-trivial aspects of the consideration is related with instability of (p ¯p )∗-atom in ns and np -states due to coupling of these states with the annihila-tion channels.Properties of the mixed nl -levels are investigated depending on the value of external static electric ﬁeld.Speciﬁc resonance-like dependence of eﬀective annihilation widths on the strength of the ﬁeld is revealed.1Introduction When antiproton enters a matter it is slowed down and captured eventually by atom forming an antiprotonic atom.From the general point of view this new physical object is of the great interest.For the long time the experimental methods to investigate an-tiprotonic atoms have been limited by studying their X-ray radiation and the products of antiproton annihilation at the end of cascade transitions.However,about 15years agothe investigations of these atoms have got on the new qualitative level especially due to the new experimental methods (see [1,2]and references therein)that used antiprotonic beam from storing ring of LEAR operated in CERN up to 1996.New setup AD (”an-tiproton decelerator”)that has been operating since the end of 2001opens,in deﬁnite aspects,even more possibilities for experimental study of antiprotonic atoms.In particu-lar,in the frame of ASACUSA project [3]it is supposed,among other experiments,direct observation and investigation of antiprotonic atoms formation in very rareﬁed gases.The new experimental possibilities pose various problems of the theory of antiprotonic atoms that were not considered early because they seemed to be of little importance in the former experimental conditions.One of such problem could be an inﬂuence of ex-ternal static electric ﬁeld on the properties of antiprotonic atoms,especially antiprotonic hydrogen.Static electric and magnetic ﬁelds can be generated by some parts of an exper-imental setup,therefore they have to be taken into account in precision measurements of the properties of excited (p ¯p )atom.On other hand,a special choice of the ﬁelds could be used in order to obtain an additional information on the properties of antiprotonic atoms.According to current concepts of the theory of exotic atom formation (see,e.g.,[4,5]),the antiprotonic atoms are formed initially in highly exited states with principal quantum number n n 0≃√(1≪l n−1),whereµis a reduced mass of the¯p-nucleus system in the units of electron mass(so,for the formation in atomic hydrogenµ=918,n0=30).When (p¯p)nl atom is formed in molecular hydrogen,the distribution over quantum number is more complicated,however the probability of population of the states with large n and l remains rather appreciable.Among the highly excited states,speciﬁc interest can present circular orbits with l=n−1and nearly-circular orbits.In isolated antiprotonic hydrogen atom these states can decay only by radiative E1-transition.Radiative life time of hydrogen-like atom at large n,l can be estimated by the equation[6]τγ(nl)≃(n3l2/µZ4)·84.5ps(1) that givesτγ=2.09µs for the circular orbit with n=30of antiprotonic hydrogen. This life time is of the same order of value as for antiprotonic helium metastable states [1],therefore the same high-precision method of laser-induced transition could be,in principle,applied for the study of energy structure and dynamics of the excited states of antiprotonic hydrogen.However,the(p¯p)atom,as compare with(¯p He+),may be less stable against atomic collisions and inﬂuence of externalﬁelds,because a most part of the(p¯p)nl states with a deﬁnite n is degenerated in l,contrary to antiprotonic helium. Therefore theoretical study of the quenching eﬀects on the long-lived states of antiprotonic hydrogen is important for the possible future experiments.One of the most important factors to quench long-lived states is the electricﬁeld arising in the processes of atomic collisions or as a results of the external conditions.The dynamical(collisional)Stark eﬀect in hadronic hydrogen atoms was discussed in the literature for a long time[6,7]. However the inﬂuence of the external static electricalﬁeld,as far as we know,was not discussed in the literature,in spite of the seeming simplicity of this eﬀect.In this paper we discuss the inﬂuence of electricﬁeld on the splitting and decay rates of highly-excited (n=30)states of antiprotonic hydrogen atoms.2Formulation of the problemThe states with large quantum numbers n,l of isolated antiprotonic hydrogen(p¯p)nl are long-lived,because annihilation in the states with l≫1is practically absent and,on other hand,these states have large radiative life times.However,if some external action forces transitions of the(p¯p)system to the states with low orbital angular momenta,then antiproton will annihilate quickly.In the problem under consideration an external action is produced by the static external electricﬁeld.Formally this problem is formulated as follows.If the nuclear(p¯p)-interaction is disregarded,all the states nl of antiprotonic hydrogen atom will be degenerated in l.In the real system nuclear interaction is important in the states with low angular momenta and it produces the both shifts and annihilation widths of the levels,or,in other words,complex shifts∆E nl=−ǫnl−iΓnl/2.(2) The estimations show that these values at n∼30are important for l=0,1and can be neglected for l≥2.So,the complex shifts remove the degeneration of the ns and np−levels,whereas other levels remain to be degenerated.A dependence of the complexshifts on the principal quantum number can be obtained taking into account that the radius of annihilation region and of nuclear interaction is small as compare with a radius of the antiprotonic hydrogen atom.Radial wave function of antiprotonic atom this region should have the simple form R nl(r)≃C nl·r l.It allows to express the dependence the complex shifts∆E nl on n in terms of the coeﬃcients C nl:∆E nl=∆E l+1,l|C nl/C l+1,l|2(3) The coeﬃcients C nl are estimated,as a rule,with the hydrogen-like wave functions that givesΓns=Γ1s/n3,(4)Γnp=Γ2p·32(n2−1)/(3n5),(5) and similarly forǫnl.As the input data we have taken the following values for the energy shifts and widths[8]:Γ1s/2=561eV,ǫ1s=691eV,Γ2p/2=17meV,ǫ2p=0.(6)With these values we obtain from the Eqs.(4),(5)for the states with n=30:Γns/2=20.78meV,ǫns=25.59meV,Γnp/2=0.00671meV,ǫnp=0.(7)Total hamiltonian H of the antiprotonic hydrogen atom in the external electricﬁeld can be written as a sum of two terms,H=H0+V,(8)where H0is a diagonal matrix with elementsnl|H0|nl′ =δll′(δl0∆E ns+δl1∆E np).(9) The matrix of interaction of the atom with the electricﬁeld E directed along Oz axis has the form:nlm|V|nl′m′ =eEr0(3/2)ntheﬁeld less than a critical value,at which non-diagonal matrix element nl|V|n′l′ is comparable with the distance between the levels with diﬀerent n.It is easy to estimate that for the levels with n≃30this critical value of theﬁeld is E a∼109V/cm,that is far from real laboratoryﬁelds.It should be noted that in the problem under consideration there are also two other critical values of theﬁeld.Theﬁrst one is theﬁeld that mixes eﬀectively ns and np states, and other one is that mixed np and nd states,the latter being degenerated with all other nl states for l>2.With the above-mentioned values of strong interaction shifts and annihilation widths of the ns and np states,we estimate the corresponding criticalﬁelds as E b∼3.3·106V/cm for a mixing of ns and np at n=30,and E c∼2000V/cm for a mixing of np and nd states.We restrict our consideration by theﬁelds up to5000V/cm, therefore only third critical value E c of theﬁeld is covered by these calculations.For the further discussion of the obtained results let us remember also,that the prob-lem of Stark mixing in the degenerated(without initial shifts and widths)hydrogen-like system at theﬁxed n has the exact solution in the parabolic coordinates[9].Eigenstates of a such system are labeled by parabolic quantum numbers n1,n2,m(n1+n2+|m|+1=n), the splitting of the levels is linear in electricﬁeld,whereas the coeﬃcients nlm|n1n2m of mixing of the states with diﬀerent l do not depend on the value of theﬁeld and can be expressed in terms of Clebsh-Gordan coeﬃcients,nlm|n1n2m 2= kν1kν2|lm 2,(11) where k=(n−1)/2,ν1=(n1−n2+m)/2,ν2=m−ν1.Therefore the admixture of ns-state to all parabolic states with m=0should be ns|nn1 2=1/n,and the weights of the np-state in the parabolic states are np,m|nn1,m 2=0.019÷0.025at n=30.These relationships could describe the eﬀect of externalﬁeld on antiprotonic hydrogen at very high values of the electricﬁeld(E b<E<E a).However for the realistic values of E<E b the inﬂuence of theﬁeld can not be predicted without calculations.The results of our calculations are shown on Figs.1-4.On theseﬁgures the shifts W(E)and widthsΓ(E)of the states are presented in the relative units of|W max|andΓmax, which are the maximum values of these quantities in the considered interval of electric ﬁelds(0≤E≤5000V/cm).Diﬀerent types of dependencies of the shifts on the value E of electricﬁeld are shown on Figs.1-2for several levels with m=0.The levels are labeled by the indexes l that correspond to the quantum numbers of the states in the limit E=0.With respect to the dependence of the shifts on E,the levels can be divided into two main types.The shifts are negative for l≤14and positive for l≥16,and in the both cases they rise in absolute value with increasing of the electricﬁeld.Within the intermediate interval l∈13−16 the shifts are very small and change the signs.It is seen from Fig.2that in this region the shifts are nonlinear in E and,moreover,they behave themselves for theﬁrst sight unusually,showing a resonance-like behaviour at E∼E c.However,the nature of a such behaviour is quite clear-this is a result of some crossing of the levels that takes place with a change of the values of electricﬁeld.For the levels with|m|=1we observe a similar behaviour with E.The widths of the levels with m=0are shown on Figs.3-4depending on the value of electricﬁeld.For the states with l≤13and l≥16the widths grow with increasing of the electricﬁeld,however in the aforementioned interval13≥l≤16the widths depend10002000300040005000E,V cm -1-0.8-0.6-0.4-0.2W W max(a)10002000300040005000E,V cm 0.20.40.60.81W W max (b)Figure 1:The dependence of the shifts of (p ¯p )states on electric ﬁeld.Part (a):l =1,W max =3.7·10−5eV;part (b):l =28,W max =3.43·10−5eV.10002000300040005000E,V cm -1-0.8-0.6-0.4-0.2W W max (a)10002000300040005000E,V cm 0.10.20.30.40.5W W max (b)Figure 2:Resonance-like dependence of the shifts of (p ¯p )states on electric ﬁeld.Part (a):l =14,W max =2.62·10−6eV;part (b):l =15,W max =1.95·10−9eVon the ﬁeld in a resonance-like manner.The reason of this phenomenon is the same as for the shifts,i.e.it is connected with the crossing of levels in the static electric ﬁeld.The shift and width of the ns state are practically unchanged at the considered values of E .It is related with the large values of the ’self’shift and width,or,in other words,with the fact that the value of E is small as compare with critical ﬁeld E b as estimated above.Thus the obtained values of ’induced’widths of all the states with l =0are due to the inﬂuence of np-states in the considered interval of electric ﬁelds.At larger electric ﬁelds the contribution of ns states would be a more essential.4ConclusionIn this paper we have made the analysis of the splitting and annihilation widths of the levels of antiprotonic hydrogen atom in the static external electric ﬁeld.As compare with the theoretical case when all the levels are degenerated and the exact analytical solution of this problem exists,we meet here a more complicated situation.This complication10002000300040005000E,V cm 0.20.40.60.81max(a)10002000300040005000E,V cm0.20.40.60.81 max (b)Figure 3:Dependence of the widths on the value of electric ﬁeld.Part (a):l =1;Γmax =3.42·1081/s;part (b):l =28,Γmax =4.52·1081/s.10002000300040005000E,V cm 0.20.40.60.81max(a)10002000300040005000E,V cm 0.20.40.60.81 max (b)Figure 4:Resonance-like dependence of the widths on the value of electric ﬁeld.Part (a):l =14,Γmax =1.51·1091/s;part (b):l =16,Γmax =1.52·1091/s.is related with the strong interaction shifts and annihilation widths of ns and np states participated in the mixing of nl levels of the antiprotonic atom.The results of the paper can be formulated as follows:a)due to mixing of diﬀerent nl states (l >1)with np states at the value of electric ﬁeld E ∼1000V/cm,all the states acquire the widths of order 108÷1091/s.The relevant shifts for the most part of the states are linear in E and have the order of value 10−5eV.b)Contribution of the ns state into the widths of other levels is negligible at the considered values of electric ﬁeld (E ≤5000V/cm),because the ns state is very distant in complex energy from all other levels and can be admixed to these states at E ∼3·106V/cm.As a result,the main contribution to the widths of the mixed levels gives np state.c)For the states that are close to the point,where the sign of the shift is changed,the shifts and widths of exact states have a resonance-like dependence on the value of electric ﬁeld.The ’resonance’value of electric ﬁeld is of the same order as critical value E c ,which provides strong mixing of the np state with other states (l ≥2).This phenomenon is due to a crossing of the levels at some value of the electric ﬁeld.AcknowledgementsThis investigation was supported by Russian Foundation for Basic Research as a part of the project03-02-16616.Authors thank to N.P.Yudin for the useful discussions.One of the authors(G.K.)thanks to Y.Yamazaki for attracting our interest to the considered problem.References[1]T.Yamazaki,N.Morita,R.S.Hayano,E.Widmann and J.Eades,Physics Reports366(2002)183.[2]A.Bertin,M.Bruschi,M.Capponi et al.,Phys.Rev.A54(1996)5441;E.Lodi Rizzini,A.Bianconi,G.Bonomi et al.,Phys.Lett.B507(2001)19.[3]ASACUSA collaboration.Status report CERN/SPSC2002-002,SPSC/M-674,Jan.2002.[4]G.Ya.Korenman,Hyperﬁne Interaction,101/102(1996)81.[5]J.S.Cohen,Phys.Rev.A56(1997)3583.[6]K.Omidvar,Atomic Data and Nucl.Data Tables28(1983)1.[7]M.Leon and H.A.Bethe,Phys.Rev.127(1962)636.[8]T.P.Terada and R.S.Hayano,Phys.Rev.C55(1996)73.[9]ndau and E.M.Lifshits,Quantum Mechanics,Fizmatgiz,Moscow,1963,§77.。

幽门螺旋杆菌感染治疗最新指南

解读美国胃肠病学会幽门螺旋杆菌感染治疗最新指南作者：姚瑜作者单位：中国医药集团四川抗菌素工业研究所,成都,610051刊名：国外医药（抗生素分册）英文刊名：WORLD NOTES ON ANTIBIOTICS年，卷(期)：2007，28(6)被引用次数：0次1.Everhart J E Recent developments in the epidemiology of Helicobacter pylori 20002.Peterson W L.Fendrick A M.Cave D R Helicobacter pylori-related disease:guidelines for testing and treatment 20003.Howden C W.Hunt R H Guidelines for the management of Helicobacter pylori infection 19984.Paptheodoridis G V.Sougioultzis S.Archimandritis A J Effects of Helicobacter pylori and nonsteroidal antiinflammatory drugs on peptic ulcer disease:a systematic review 20065.Leodolter A.Kulig M.Brasch H A meta-analysis comparing eradication,healing and relapse rates in patients with Helicobacter pylori-associated gastric or duodenal ulcer 20016.Ford A C.Delaney B C.Forman D Eradication therapy in Helicobacter pylori positive peptic ulcer disease:systematic review and economic analysis 20047.Sharma V K.Sahai A V.Corder F A Helicobacter pylori eradication is superior to ulcer healing with or without maintenance therapy to prevent further ulcer haemorrhage 20018.Liu C C.Lee C L.Chan C C Maintenance treatment is not necessary after Helicobacter pylori eradication and healing of bleeding peptic ulcer 20039.Gisbert J P.Khorrami S.Carballo F H.pylori eradication therapy vs.antisecretory non-eradication therapy (with or without long-term maintenance antisecretory therapy) for the prevention of recurrent bleeding from peptic ulcer 2004(02)10.Farinha P.Gascoyne R D Helicobacter pylori and MALT lymphoma 200511.Montalban C.Norman F Treatment of gastric mucosa associated lymphoid tissue lymphoma:Helicobacter pylori eradication and beyond 200612.Wundisch T.Thiede C.Morgner A Long-term follow-up gastric MALT lymphoma after Helicobacter pylori eradication 200113.Nakamura S.Matsumoto T.Suekane H Long-term clinical outcome of Helicobacter pylori eradicationfor gastric mucosa-associated lymphoid tissue lymphoma with a reference to second-line treatment 200514.Chen L T.Lin J T.Tai J J Long-term results of antiHelicobacter pylori therapy in early-stage gastric high grade transformed MALT lymphoma 200515.Talley N J.Vakil N Practice Parameters Committee of the American College ofGastroenterology.Guidelines for the management of dyspepsia 200516.Midolo P.Marshall B J Accurate diagnosis of Helicobacter pylori.Urease tests 200017.Perna F.Ricci C.Gatta L Diagnostic accuracy of a new rapid urease test (Pronto Dry),before andafter treatment of Helicobacter pylori infection 2005ine L.Lewin D.Naritoku W Prospective comparison of commercially available rapid urease testsfor the diagnosis of Helicobacter pylori 199619.Lee J M.Breslin N P.Fallon C Rapid urease tests lack sensitivity in Helicobacter pylori diagnosis when peptic ulcer disease presents with bleeding 200020.Tu T C.Lee C L.Wu C H Comparison of invasive and noninvasive tests for detecting Helicobacter pylori infection in bleeding peptic ulcers 199921.Grino P.Pascual S.Such J Comparison of stool immunoassay with standard methods for detection of Helicobacter pylori infection in patients with upper gastrointestinal bleeding of peptic origin 2003 ine L A.Nathwani R A.Naritoku W The effect ofGI bleeding on Helicobacter pylori diagnostic testing:a prospective study at the time of bleeding and 1 month later 200523.Gisbert J P.Abraira V Accuracy of Helicobacter pylori diagnostic tests in patients with bleeding peptic ulcer:a systematic review and meta-analysis 200624.Woo J S.el-Zimaity H M.Genta R M The best gastric site for obtaining a positive rapid urease test 199625.Chey W D.Woods M.Scheiman J M Lansoprazole and ranitidine affect the accuracy of the C-urea breath test by a pH-dependent mechanism 1997ine L.Estrada R.Trujillo M Effect of protonpump inhibitor therapy on diagnostic testing for Helicobacter pylori 199827.el-Zimaity H M Accurate diagnosis of Helicobacter pylori with biopsy 200028.Dixon M F.Genta R M.Yardley J H Classification and grading of gastritis.the updated Sydney system.International workshop on the histopathology of gastritis,Houston 1994 199629.Cutler A F.Havstad S.Chen K M Accuracy of invasive and non-invasive tests to diagnose Helicobacter pylori infection 199530.van IJzendoorn M heij R J.de Boer W A The importance of corpus biopsies in the determination of Helicobacter pylori infection 200531.Perez-Perez G I Accurate diagnosis of Helicobacter pylori.Culture,including transport 200032.Makristathis A.Hirschl A M.Lehourst P Diagnosis of Helicobacter pylori Infection 200433.Lehours P.Ruskone-Fourmestraux vergne A Which test to use to detect Helicobacter pylori infection in patients with low-grade gastric mucosa-associated lymphoid tissue lymphoma? 200334.Zsikla V.Hailemariam S.Baumann M Increased rate of Helicobacter pylori infection detected by PCR in biopsies with chronic gastritis 2006wson A J.Elviss N C.Owen R J Real-time PCR detection and frequency of 16 S rDNA mutations associated with resistance and reduced susceptibility to tetracycline in Helicobacter pylori from England and Wales 200536.Rimbara E.Noguchi N.Yamaguchi T Development of a highly sensitive method for detection ofclarithromycin-resistant Helicobacter pylori from human feces 2005Helicobacter pylori DNA sequences by TaqMan real-time polymerase chain reaction 200638.Ho G Y.Windsor H M Accurate diagnosis of Helicobacter pylori.Polymerase chain reaction tests 200039.Ho B.Marshall B J Accurate diagnosis of Helicobacter pylori.Serologic testing 200040.Loy C T.Irwig L M.Katelaris P H Do commercial serological kits for Helicobacter pylori infection differ in accuracy? A meta-analysis 199641.Chey W D.Murthy U.Shaw S A comparison of three finger stick,whole blood antibody tests for Helicobacter pylori infection:An United States,multicenter trial 199942.Nurgalieva Z Z.Graham D Y Pearls and pitfalls of assessing Helicobacter pylori status 200343.Hoang T T.Wheeldon T U.Bengtsson C Enzyme liked immunosorbent assay for Helicobacter pylori needs adjustment for the population investigated 200444.Gisbert J P.Pajares J M Review article:13 C-urea breath test in the diagnosis of Helicobacter pylori infection-a critical review 200445.Chey W D Accurate diagnosis of Helicobacter pylori.14C urea breath test 200046.Steen T.Berstad K.Meling T Reproducibility of the 14 C-urea breath test repeated after 1 week 199547.Leodolter A.Dom'ingues-Mu~noz J E.von Arnim U Validity of a modified 13C-urea breath test forpre-and post-treatment diagnosis of Helicobacter pylori infection in the routine clinical setting 199948.Chey W D.Metz D C.Shaw S Appropriate timing of the C-urea breath test to establish eradication of Helicobacter pylori infection 200049.Perri F.Giampiero M.Neri M Helicobacter pylori antigen stool test and 13C-urea breath test in patients after eradication treatments 200250.Gatta L.Ricci C.Tampieri A Accuracy of breath tests using low doses of 13C-urea to diagnose Helicobacter pylori infection:a randomised controlled trial 200651.Chey W D.Murthy U.Toskes P The 13C-urea blood test accurately detects active Helicobacter pylori infection:An United States,multicenter trial 199952.Ahmed F.Chey W D.Murthy U Evaluation of the Ez-HBT Helicobacter blood test to establish Helicobacter pylori eradication 200553.Graham D Y.Opekun A R.Hammoud F Studies regarding the mechanism of false negative urea breath tests with proton pump inhibitors 200354.Cutler A F.Elnaggar M.Brooks E Effect of standard and high dose ranitidine on C-urea breath test results 199855.Savarino V.Tracci D.Dulbecco P Negative effect of ranitidine on the results of urea breath test for the diagnosis of Helicobacter pylori 200156.Graham D Y.Opekun A R.Jogi M False negative urea breath tests with H2-receptorantagonists:Interactions between Helicobacter pylori density and pH 200457.Gatta L.Vakil N.Ricci C Effect of proton pump inhibitors and antacid therapy on C urea breath tests and stool test for Helicobacter pylori infection 200458.Gatta L.Ricci C.Tampieri A Accuracy of breath tests using low doses of C-urea to diagnose Helicobacter pylori infection:A randomised controlled trial 200659.Gisbert J P.Pajares J M Stool antigen test for the diagnosis of Helicobacter pylori infection:A systematic review 200460.Gisbert J P.de la Morena F.Abraira V Accuracy of monoclonal stool antigen test for the diagnosis of H.pylori infection:A systematic review and meta-analysis 200661.Malfertheiner P.Megraud F.O' Morain C Current concepts in the management of Helicobacter pylori infection-the Maastricht 2-2000 Consensus Report 200262.Viara D.Vakil N.Menegatti M The stool antigen test for detection of Helicobacter pylori after eradication therapy 200263.Odaka T.Yamaguchi T.Koyama H Evaluation of the Helicobacter pylori stool antigen test for monitoring eradication therapy 200264.Vakil N.Rhew D.Soll A The cost-effectiveness of diagnostic testing strategies for Helicobacter pylori 200065.Bravo L E.Realpe J L.Campo C Effects of acid suppression and bismuth medications on the performance of diagnostic tests for Helicobacter pylori infection 199966.Manes G.Balzano A.Iaquinto G Accuracy of the stool antigen test in the diagnosis of Helicobacter pylori infection before treatment and in patients on omeprazole therapy 200167.Grino P.Pascual S.Such J Comparison of stool immunoassay with standard methods for detection of Helicobacter pylori infection in patients with upper gastrointestinal bleeding of peptic origin 2003 68.Peitz U.Leodolter A.Kahl S Antigen stool test for assessment of Helicobacter pylori infection in patients with upper gastrointestinal bleeding 200369.van Leerdam M E.Van Der Ende A.ten Kate F J W Lack of accuracy of the noninvasive Helicobacter pylori stool antigen test in patients with gastroduodenal ulcer bleeding 200370.Lin H J.Lo W C.Perng C L Helicobacter pylori stool antigen test in patients with bleeding peptic ulcers 20041.期刊论文"温胃舒或养胃舒治疗幽门螺杆菌相关性慢性胃炎和消化性溃疡"全国多中心临床研究科研协作组. "Wenweishu (温胃舒) /yangweishu ( 养胃舒) in the Treatment of Helicobacter pylori Positive Patients with Chronic Gastritis and Peptic Ulcer" Study Group温胃舒或养胃舒治疗幽门螺杆菌相关性慢性胃炎和消化性溃疡的全国多中心临床研究-中华医学杂志2010,90(2)目的探讨标准三联疗法泮托拉唑+克拉霉素+甲硝唑(PCM)联合温胃舒或养胃舒对幽门螺杆菌(Hp)相关性慢性胃炎和消化性溃疡患者的Hp根除率及症状缓解率,并观察温胃舒或养胃舒对胃溃疡愈合的影响.方法全国11个中心642例符合标准的患者随机分为PCM组(222例):泮托拉唑40 mg2次/d+克拉霉素500 mg2次/d+甲硝唑400 mg2次/d,疗程7 d;PCM+温胃舒组(196例);PCM+养胃舒组(224例).于治疗停药4周后复查(~14)C-尿素呼气试验,胃溃疡患者治疗结束复查胃镜.结果按意向治疗(ITT)分析显示,PCM+温胃舒组、PCM+养胃舒组及PCM组Hp根除率分别为62.2%(122/196)、60.3%(135/224)和57.2%(127/222)(与PCM组比较,P=0.295、0.512);按符合方案(PP)分析分别为70.1%(122/174)、65.2%(135/207)和62.3%(127/204)(与PCM组比较,P=0.108、0.532).PP分析3组胃溃疡愈合率分别为100.0%(18/18)、86.4%(19/22)和61.9%(13/21);PCM+温胃舒组胃溃疡愈合率与PCM组比较差异有统计学意义(P=0.004).PCM+养胃舒组及PCM+温胃舒组患者腹痛、腹胀症状缓解率均显著高于PCM组(均P＜0.01).各组均只有少数患者发生不良反应.结论温胃舒或养胃舒与标准三联疗法联合应用虽不能明显提高Hp的根除率,但可增加慢性胃炎及消化性溃疡患者症状缓解率及溃疡愈合率.2.期刊论文刁萍萍.杜奕奇.李兆申.李淑德.舒建昌.陈锡美.周中杰.陆和平.姜慧卿.刘希双.鲁临.杨力.时昭红.刘鹏飞.屠惠明.陈国昌.张志坚.DIAO Ping-ping.DU Yi-qi.LI Zhao-shen.LI Shu-de.SHU Jian-chang.CHEN Xi-mei. ZHOU Zhong-jie.LU He-ping.JIANG Hui-qing.LIU Xi-shuang.LU Lin.YANG Li.SHI Zhao-hong.LIU Peng-fei.TUHui-ming.CHEN Guo-chang.ZHANG Zhi-jian幽门螺杆菌阴性消化性溃疡与出血关系的多中心对照研究-中华消化内镜杂志2010,27(8)目的明确中国大陆地区幽门螺杆菌(Hp)阴性消化性溃疡与出血的关系.方法拟定于2006年4月至2007年3月期间在国内14个研究中心中进行,每个中心预期调查30例经急诊内镜诊断为胃溃疡和(或)十二指肠溃疡合并出血的患者(PUB组),同时调查30例不伴出血的胃溃疡和(或)十二指肠溃疡患者作为对照(PU组).共拟入选840例患者,消化性溃疡合并及不合并出血组各420例.在内镜检查中采用快速尿素酶试验和病理检测Hp感染,并对初次检查Hp阴性者于1个月后进行尿素呼气试验复查.结果共617例患者纳入分析,其中PUB组263例、PU组354例,2组在性别比、平均年龄等一般状况方面差异无统计学意义(P均＞0.05).PUB组Hp阳性率61.2%(161/263)显著低于PU组的87.9%(311/354)(P＜0.001);PUB组Hp阳性的溃疡出血发生复合溃疡的比例7.5%(12/161)显著高于Hp阴性溃疡出血者1.0%(1/102)(P=0.018),但两者在平均发病年龄、性别比、呕血发生率、十二指肠球部溃疡发生率、胃溃疡发生率及溃疡平均直径方面差异无统计学意义(P均＞0.05).对于初次Hp阴性的溃疡出血患者,1个月后的呼气试验复查未发现阳性病例.结论目前中国大陆Hp阴性溃疡在消化性溃疡出血中的比例较高,Hp阴性溃疡可能更容易并发消化道出血,需要引起消化专科医生的重视.3.期刊论文张保环.干超士.柴军土.徐惠萍.乐怀浙.ZHANG Bao-huan.GAN Chao-shi.CHAI Jun-tu.XU Hui-ping.LE Huai-zhe消化性溃疡伴幽门螺杆菌感染患者184例干预治疗分析-中国基层医药2008,15(7)目的探讨消化性溃疡伴幽门螺杆菌(Hp)感染患者干预治疗的临床效果.方法将184例消化性溃疡伴Hp感染患者随机分为两组,常规组给予单纯药物治疗:泮托拉唑和替普瑞酮;干预组给予药物(同上)和生活方式及个人饮食习惯干预治疗;两组疗程均为6周.根除Hp治疗:泮托拉唑加用克拉霉素和阿莫西林,疗程为1周.疗程结束后对比两组疗效.结果临床症状完全缓解时间:干预组中77例第1周完全缓解;常规组中56例第1周完全缓解;两组患者第1周临床症状完全缓解率比较差异有统计学意义(P<0.01).溃疡愈合情况:在疗程结束后胃镜复查显示,干预组90例溃疡治愈,常规组83例溃疡治愈,两组溃疡愈合率比较差异有统计学意义(P<0.05).Hp根除情况:干预组85例,常规组83例,两组比较差异无统计学意义(P>0.05).结论药物结合生活方式及个人饮食习惯的干预治疗能加快临床症状消失,提高溃疡治疗效果.4.期刊论文吴春城.谢会忠.WU Chun-cheng.XIE Hui-zhong非甾体抗炎药和幽门螺杆菌感染对消化性溃疡并发出血的影响-中国全科医学2010,13(8)目的探讨服用非甾体抗炎药(NSAIDs)和幽门螺杆菌(H.pylori)感染与消化性溃疡并发出血的关系.方法收集2007年1月-2009年7月在新疆医科大学第一临床医学院消化内科收治的消化性溃疡患者205例,均行内镜检查确诊(除外复合溃疡),并行病理学检查排除胃癌.对消化性溃疡并发出血的危险因素行单因素和多因素分析.结果 205例消化性溃疡患者中,男150例(73.2%),女55例(26.8%);中位年龄49(12～88)岁;并发出血87例(42.4%).在单因素分析中,出血组与未出血组患者中年龄≥60岁者、既往有消化道出血史者、心脑血管病史者、有多个溃疡者所占比例间差异均有统计学意义(P＜0.01);进一步行Logistic逐步回归分析,发现年龄≥60岁、有消化性溃疡史、消化道出血史、心脑血管病史和单纯H.pylori感染、单纯服用NSAIDs、H.pylori感染同时服用NSAIDs为消化性溃疡并发出血的危险因素.结论 H.pylori感染并未增加溃疡并发出血的危险性,但与服用NSAIDs、年龄≥60岁、消化性溃疡或出血史、心脑血管病史等因素联合可增加溃疡并发出血的危险性.5.期刊论文孟灵梅.周丽雅.林三仁.闫秀娥.丁士刚.黄永辉.顾芳.张莉.李渊.崔荣丽.张冬红.张静.MENG Ling-mei.ZHOU Li-ya.LIN San-ten.YAN Xiu-e.DING Shi-gang.HUANG Yong-hui.GU Fang.ZHANG Li.LI Yuan.CUI Rong-li.ZHANG Dong-hong.ZHANG Jing幽门螺杆菌与消化性溃疡关系的10年随访研究-中华消化杂志2009,29(6)目的探讨根除幽门螺杆菌(Helicobacter pylori,Hp)后10年间十二指肠球部溃疡(DU)、胃溃疡(GU)发病情况.方法选择胃癌高发区山东烟台高陵镇随机抽样自然人群进行内镜普查,其中Hp阳性者552例均分为治疗组和安慰剂组,治疗组276例予以奥美拉唑20 mg、克拉霉素0.5 g和阿莫西林1.0 g,每日2次口服,疗程7 d.停药1个月后治疗组行13C-尿素呼气试验(13C-UBT)证实根除成功.此后对两组在10年期间进行内镜随访(第1、5、8和10年),观察两组患者消化性溃疡发病率的变化及复发情况,同时观察两组Hp感染状态的变迁.结果治疗组消化性溃疡第1、5和8年的发病率分别为3.70%、5.86%和4.40%,均明显低于安慰剂组(12.85%、14.93%和9.39%,P值分别=0.0002、0.0017和0.0440).随访10年间,治疗组消化性溃疡新发病例数及复发病例数均低于安慰剂组,两组间差异均有统计学意义(P值均<0.05).治疗组Hp再感染率较高,第10年时Hp阳性率达46.4%.根据Hp感染状态重新进行分组,结果显示随访10年间Hp阴性组消化性溃疡的发病率均低于Hp阳性组(P值均<0.05).结论根除Hp治疗后消化性溃疡的发病率和复发率均明显降低,消化性溃疡患者根除Hp是必要的.成功根除Hp后再感染率仍较高.6.期刊论文邓淑娟.李兴华.方德宁.曾钗明.DENG Shu-Juan.LI Xing-Hua.FANG De-ning.ZENG Chai-ming幽门螺杆菌babA2和胃黏膜上皮Leb抗原在不同血型中表达情况及与消化性溃疡的关系-江苏大学学报（医学版）2010,20(2)目的:研究不同血型(ABO)患者幽门螺杆菌(Helicobacter pylori,Hp)表达血型抗原结合黏附素(blood group antigen binding adhesion,babA2)和胃黏膜上皮表达Lewisb (Leb)情况,及两者与消化性溃疡的关系.方法:测定56例(25例胃炎,31例消化性溃疡)Hp阳性消化性溃疡及消化不良的患者血型,并进行内镜检查,取2块胃黏膜,一块进行Hp培养,采用PCR检测Hp babA2表达情况;另一块组织进行组织病理学检查,并应用免疫组化测定胃黏膜上皮表达Leb情况.分别比较不同血型babA2、Leb表达情况与消化性溃疡的关系.结果:56例患者中,消化性溃疡组O型血所占比例高于胃炎组及正常人群(P均<0.0125),O型血患者胃黏膜Leb评分显著高于非O型血(P<0.005),消化性溃疡组Leb评分高于胃炎组(P<0.05).Hp培养成功30例,有28例babA2阳性(7例消化性溃疡,21例胃炎),babA2阳性患者中,消化性溃疡组O型血比例高于非O型血(P<0.0125),消化性溃疡组与胃炎组O型血所占比例差异无统计学意义.结论:O型血可能是通过高表达Leb及Hp的babA2增加了消化性溃疡的发生.7.期刊论文李小刚.陈锡美.LI Xiao-gang.CHEN Xi-mei胆汁反流和幽门螺杆菌感染在胆汁反流性胃炎和消化性溃疡发病中的作用-中国内镜杂志2005,11(6)目的探讨胆汁反流和幽门螺杆菌感染在胆汁反流性胃炎和消化性溃疡发病中的作用.方法采用病理组织学检查和快速尿素酶试验对76例胆汁反流性胃炎及22例兼有胆汁反流性胃炎和消化性溃疡的患者行幽门螺杆菌检测,并与29例消化性溃疡患者作对照.结果胆汁反流性胃炎组幽门螺杆菌阳性率为31.6%(24/76例),兼有胆汁反流性胃炎和消化性溃疡组幽门螺杆菌阳性率为59.0%(13/22例),消化性溃疡组幽门螺杆菌阳性率为72.4%(21/29例),前二组比较,差异有显著意义(P＜0.05),后二组比较,差异无显著意义(P＞0.05).结论胆汁反流在胆汁反流性胃炎的发病中起主要作用,幽门螺杆菌感染在消化性溃疡的发病中起主要作用.胆汁反流和幽门螺杆菌感染在胆汁反流性胃炎和消化性溃疡的共同发病中互不明显影响,幽门螺杆菌感染所起的作用可能更大一些.8.期刊论文梅浙川.罗咏萍.何璐.吴素华根除幽门螺杆菌治疗后消化性溃疡的流行病学研究附30993例胃镜资料分析-重庆医学2005,34(5)目的了解近20年来幽门螺杆菌(Hp)根除治疗后消化性溃疡(Pu)的发病情况及变化特点.方法回顾性分析我院24年来胃镜检查消化性溃疡的临床资料,以1985年1月为分界,之前为未开展根除Hp治疗消化性溃疡期,之后为开展根除Hp治疗消化性溃疡期.结果1985～1994年和1995～2003年消化性溃疡检出率分别为14.92%和14.80%,与1979～1984年的17.13%比较显著下降(P＜0.05).1985～1994年和1995～2003年消化性溃疡的平均发病年龄分别为(40.64±11.65)岁和(44.72±13.55)岁,分别高于1979～1984年的(38.13±13.20)岁,(P＜0.05);＞60岁的老年患者1995年后发病显著增高(P＜0.01).1985～1994年和1995～2003年的男女之比为3.73:1和2.38:1,显著低于1979～1984年的7.72:1(P＜0.05).24年来发病均以1～4月为高峰,6～9月最低.结论开展根除Hp治疗后消化性溃疡的发病率下降、发病年龄增大、老年人患病率增加、男女之比下降、发病季节无明显改变.9.期刊论文叶英.Ye Ying两种三联疗法治疗幽门螺杆菌相关性消化性溃疡临床观察-医学研究杂志2007,36(3)目的比较两种三联疗法治疗幽门螺杆菌相关性消化性溃疡的疗效.方法将幽门螺杆菌阳性的消化性溃疡病例120例分成两组,A组用奥美拉唑+克拉霉素+阿莫西林口服治疗,B组用奥美拉唑+呋喃唑酮+阿莫西林口服治疗,疗程均为7天.观察消化性溃疡主要症状缓解情况、Hp根除率、溃疡愈合率、有效率及药物不良反应.结果 A、B两组消化性溃疡主要症状上腹痛、嗳气、反酸、恶心、腹胀的缓解率分别为91.5%和89.3%,90.0%和94.7%,85.7%和79.3%,90.9%和90.7%,85.7%和92.5%,差异无统计学意义(P＞0.05);Hp根除率分别为91.7%和88.3%,差异无统计学意义(P＞0.05);溃疡治愈率分别为66.7%和60.0%,总有效率分别为96.7%和93.3%,差异无统计学意义(P＞0.05);不良反应发生率分别为10.0%和8.3%,差异无统计学意义(P＞0.05).结论两组方案均能有效缓解消化性溃疡症状和根除Hp,B组中因为呋喃唑酮价格低廉,不良反应轻,可推荐为治疗Hp相关性消化性溃疡的一线用药.10.期刊论文徐灿霞.肖丽君.邹惠芳.XU Canxia.XIAO Lijun.ZOU Huifang双歧杆菌三联活菌胶囊对幽门螺杆菌感染的消化性溃疡的治疗作用-中南大学学报（医学版）2010,35(9)目的:观察双歧杆菌三联活菌胶囊对幽门螺杆菌(Helicobacter pylori, H.pylori)感染的消化性溃疡的治疗作用.方法:H.pylori感染的消化性溃疡患者120例,随机分为2组:对照组用埃索美拉唑镁+阿莫西林+呋喃唑酮三联抗H.pylori治疗,治疗组用上述三联抗H.pylori治疗+双歧杆菌三联活菌胶囊,观察治疗前及治疗2周后胃液pH值、胃内菌群变化、不良反应、溃疡及糜烂愈合情况,治疗结束后4周复查14C 尿素呼气试验,观察H.pylori根除率.结果:2组治疗后胃液pH值均较治疗前明显升高(P<0.05),胃液pH值≥4时,治疗组胃液细菌培养阳性率低于对照组(分别为80.0%与97.4%,P<0.05);治疗组不良反应发生率低于对照组(分别为11.7%与30%,P<0.05);治疗2周后,治疗组与对照组溃疡治愈率分别为80.0%与73.3%(P>0.05),治疗组糜烂治愈率高于对照组(分别为68.7%与40.7%,P<0.05);治疗组H.pylori根除率高于对照组(PP分析分别为80.4%与62.3%,P<0.05).结论:在抗H.pylori治疗时加用双歧杆菌三联活菌胶囊能减少胃内细菌生长,降低不良反应,提高H.pylori根除率,促进糜烂愈合.本文链接：/Periodical_gwyykssfc200706008.aspx授权使用：昆山市中医医院(wfkszy)，授权号：cb976ed9-b1e6-4b57-98c9-9eaa00c6d361下载时间：2011年3月18日。

第一章原子核的基本性质

K. S. Krane, Introductory Nuclear Physics, P.2,3
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（3）重要的常量
• 阿伏伽德罗常数——联系了宏观与微观 › NA=6.02214199×1023/mol • 普朗克常量——能量、角动量的量子化，不确定度关系 › h = 6.62606876×10-34J· s = 4.13566727×10-22MeV· s › ħ =1.054571596×10-34J· s = 6.58211889×10-22MeV· s • 真空中的光速——越微观，越高速，必须考虑相对论效应 › c =2.99792458×108m/s • 基本电荷——质子、电子、原子核的电荷量 › e =1.602176462×10-19C • 真空中介电常数 › ε0 =8.854187817×10-12F/m
• 粒子性：particles of light
– 1900：Planck，黑体辐射 – 1905：Einstein，光电效应
– de Broglie 1924年提出实物（静质量非0）粒子也具有波粒二象性。
de Broglie wavelength:
h p
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物质波的实验证实
C60分子的干涉图像
有关核物理的理论与实验工作对20世纪的物理学发展起到了重要的作用。核物理所涉及技术的应用范围和影响，超过了其它任何学科。
……. No other field of science comes readily to mind in which theory encompasses so broad a spectrum, from the most microscopic to the cosmic, nor is there another field in which direct application of basic research contain the potential for the ultimate limits of good and evil. K. S. Krane, Introductory Nuclear Physics, P.2

质子泵抑制剂与抗血小板药

解放军总医院消化病中心
H2 receptor blockers
• Except cimetidine • No evidence that other drugs reduce stomach acid, – H2 blockers • ranitidine (Zantac) • famotidine (Pepcid) • nizatidine (Axid)
• The potential benefits of antiplatelet therapy for atherosclerotic cardiovascular (CV) disease have been amply demonstrated over the past 20 years, especially thienopyridine drugs in preventing stent thrombosis. • Antiplatelet agents increase the risk of bleeding associated with mucosal breaks in the upper and lower gastrointestinal (GI) tract. • Rational use of thienopyridines is based on weighing their risks against their benefits.
• Clopidogrel alone, aspirin alone, and their combination are all associated with increased risk of GI bleeding. • Use of a PPI or histamine H2 receptor antagonist (H2RA) reduces the risk of upper GI bleeding compared with no therapy. • PPIs reduce upper GI bleeding to a greater degree than do H2RAs.

ispd guidelines 预防腹膜炎

Peritoneal Dialysis International, Vol. 31, pp. 614–630doi: 10.3747/pdi.2011.000570896-8608/11 $3.00 + .00Copyright © 2011 International Society for Peritoneal DialysisISPD POSITION STATEMENT ON REDUCING THE RISKS OF PERITONEALDIALYSIS–RELATED INFECTIONSBeth Piraino,1 Judith Bernardini,1 Edwina Brown,2 Ana Figueiredo,3David W. Johnson,4 Wai-Choong Lye,5 Valerie Price,6 Santhanam Ramalakshmi,7 and Cheuk-Chun Szeto 8University of Pittsburgh School of Medicine,1 Pittsburgh, Pennsylvania, USA; Imperial College Healthcare NHS Trust,2 London, UK; Faculdade de Enfermagem,3 Nutriccao e Fisioterapia, Pontificia Universidade Catolicado Rio Grande do Sul, Brazil; Princess Alexandra Hospital and School of Medicine,4University of Queensland, Brisbane, Australia; Mount Elizabeth Medical Centre,5 Singapore; Saint JohnRegional Hospital,6 Horizon Health Network, St. John, New Brunswick, Canada;Sri Ramachandra University No 1,7 Ramachandra Nagar, Porur, Chennai,India; and Department of Medicine and Therapeutics,8 Prince ofWales Hospital, The Chinese University of Hong Kong,Hong Kong SAR, PR ChinaSPECIAL ARTICLEF or a peritoneal dialysis (PD) program to be successful, close attention must be paid to preventing PD-related infections (defined as exit-site infections, tunnel infec-tions, and peritonitis). The variation in peritonitis rates in recently published studies (1–20) is astonishing: from a low of 0.06 episodes per year in a Taiwanese program to a high of 1.66 episodes per year at risk in an Israeli pediatric program (Table 1). Those rates mean that an individual patient, on average, may expect to have peritonitis as rarely as once every 17 years in one cen-ter, or as frequently as once every 7 months in another. Even at centers within a single country, there is often a marked variation in the peritonitis rate. For example, the Scottish registry has centers with rates that range from 0.43 episodes to 0.89 episodes per year (1), the LondonThames centers vary from 0.14 episodes to 1.0 episodes per year (9), and the Austrian Study Group centers range from 0.07 episodes to 0.60 episodes per year (10). Ex-planations for such marked variations are lacking, but are likely related at least in part to differences in patient training and in infection-prevention protocols. Varia-tions in the accuracy with which peritonitis episodes are recorded may also contribute in part to the differences in reported rates.Studies on preventing PD-related infections are lim-ited both in number and in quality, and guidelines are therefore not yet appropriate. The present position paper is a compilation of the opinions of experts in the field, combined with the available evidence. It is intended to provide support to PD programs developing approachesto reduce PD-related infections to very low levels atall centers. Suggestions for which there is published research are labeled “evidence”; suggestions for which only case reports, limited observational studies, or theexperience of the work group are available are labeled“opinion.” We hope that this review of the problems willstimulate further research into this important topic.Specific guidelines for treating peritonitis were updated and published in 2010 (21), as were guidelines for PD Correspondence to: B. Piraino, Suite 200, 3504 Fifth A venue, Pittsburgh, Pennsylvania 15213 USA.Piraino@ Received 11 May 2011; accepted 17 May 2011Perit Dial Int 2011; 31(6):614-630 epub ahead of print: 31 Aug 2011 doi:10.3747/pdi.2011.00057KEY WORDS: Peritonitis; exit-site infections; tunnel in-fections; prevention of peritonitis; automated peritoneal dialysis; continuous ambulatory peritoneal dialysis. by guest on July 22, 2014/Downloaded fromPDI NovEMBER 2011 - voL. 31, No. 6 ISPD: REDUCING THE RISKS OF PD-RELATED INFECTIONScatheter insertion and management (22). The present position paper is directed specifically at the prevention of PD-related infections, and it is intended primarily for adult programs; however, many of the principles are likely to be applicable to pediatric programs as well.MONITORING PERITONITIS • Every program should monitor infection rates at least quarterly (23–26). (Opinion)• A team approach for continuous quality improvement (CQI) is the key to a successful PD program (25–26). (Opinion)The PD CQI team generally includes nephrologists, nurses, social workers, and dietitians. Regular meetings of the team should be held to examine all PD-related infections, identifying the root cause of each episode. If a pattern of infections develops, the team needs to investigate and to plan interventions such as retrain-ing, equipment changes, application of new protocols for exit-site care, or management of contamination (to mention just a few examples). Tracking not only the overall rates of each type of PD-related infection, but also the rates by organism will aid the team in identify-ing problems and trends. The organisms causing theperitonitis episodes can provide important clues to thepossible causality (Table 2). Peritonitis episodes caused by Staphylococcus aureus and Pseudomonas aeruginosa are often secondary to exit-site and tunnel infections with the same organisms; peritonitis episodes caused by coagulase-negative staphylococci are generally re-lated to contamination at the time of connection or tocontamination of tubing (27), and they indicate a needto re-examine training methods. The CQI team identifies problems, develops solutions, and evaluates results in an iterative fashion.Calculation of peritonitis rates should be standard-ized and should be clearly defined in any publication on peritonitis. Most observers would start to calculate the time at risk for peritonitis as the first day of training;TABLE 1Peritonitis Rates Around the WorldPatient population (n ) Episodes per Country Reference Year Adults Children Centers year at risk (n )Scotland Kavanaugh (1) 2004 1205a 0.62Japan Hoshii (2) 2006 130 0.17Canada Mujais (3) 2006 26 0.43United States Mujais (3) 2006 35a 0.37Japan Nakamoto (4) 2006 139 0.22Portugal Rodrigues (5) 2006 312 0.39Canada Fang (6) 2008 312 0.33China Fang (6) 2008 496 0.20Taiwan Tzen–Wen (7) 2008 100 0.06Turkey Akman (8) 2009 132 0.77United Kingdom Davenport (9) 2009 1904 pt–yrs a 0.82 CAPD 0.66 APD Austria Kipriva–Altfart (10) 2009 332 0.24Brazil Mores (11) 2009 680a 0.74Canada Nessim (12) 2009 4247a 0.36Spain Perez Fontan (13) 2009 641 0.38United States Qamar (14) 2009 137a 0.24Netherlands Ruger (15) 2009 205a 0.60France Castrale (16) 2010 1631b 0.36Israel Cleper (17) 2010 29 1.66Australia/New Zealand Fahim (18) 2010 4675a 0.62Australia Jarvis (19) 2010 4675a 0.60Qatar Shigidi (20) 2010 241 0.24CAPD = continuous ambulatory peritoneal dialysis; APD = automated peritoneal dialysis.a Registry data.b Elderly patients.by guest on July 22, 2014/Downloaded fromPIRAINO et al. NovEMBER 2011 - voL. 31, No. 6 PDIsome might consider the date of catheter insertion to be the starting point. The former is probably preferable, because the latter might lead to falsely low rates, espe-cially in centers that place the catheter many weeks or even months before the start of training.The rate is calculated by totaling all the peritonitis episodes that occurred during the entire time on PD (“at risk”) for all patients in the program during the period in question. That total is then divided by the time at risk in years. “Time at risk” is the sum of all days that each patient was on PD during the time in question. The days at risk are then converted to years at risk.Peritonitis episodes that occur while the patient is hospitalized and not doing self-dialysis might be exclud-ed, but the work group feels that including all episodes while the patient is on PD is the best approach. The stop points for time at risk are generally successful transplan-tation (even though the catheter may be left in place for a period of time) and transfer to hemodialysis. Time spentduring a period of temporary transfer to hemodialysisshould not be included in the time at risk.As shown in Table 1, low peritonitis rates are achiev-able. We believe that a rate of 0.36 episodes per patient per year can be reached by most programs. However, overall rates as low as 0.06 – 0.24 episodes per year at risk or 1 episode every 50 – 200 months have been reported,and so those are the goals that dialysis programs should strive to achieve (2,4,6,7,10,14,20).Yearly, each program should also examine the propor-tion of patients who are peritonitis-free. A minimum of 80% of patients should be peritonitis-free in any givenyear. Often, a small number of patients experience most of the peritonitis episodes. Those patients require close scrutiny, with the development of approaches to lower the infection risk in such patients. That effort may require more intensive training, home visits, or the training of a family member. The dialysis center personnel should closely examine the organisms causing the peritonitis and determine whether the peritonitis is relapsing,repeat, or recurrent (as discussed later in this position paper). A program may also find it helpful to calculatea median rate for all the individual patient rates. In a successful program, the median rate will be zero, with most patients having no peritonitis episodes in a given year.It is very important to examine organisms not just as a percentage of the total but also as an absolute rate (episodes per year). Only in this way can the results of a center be compared, organism-by-organism, with the results in the literature. To evaluate problem areas in aprogram, the rates of infection by organism should beexamined and followed on a regular basis because of theimportant information provided.For example, at one center, 30% of all peritonitis is caused by S. aureus, similar to the proportion reported at another center. However, if the first center has an overall peritonitis rate of 0.2 episodes per year, the S. aureus rate is then 0.06 episodes per year. That rate can then be compared to the rate at the second center whose overall peritonitis rate is 0.60 episodes per year, for a S. aureus peritonitis rate of 0.18 episodes per year. The second center therefore has a rate of S. aureus peritonitis that is 3 times the rate at the first center, despite a similar proportion of S. aureus episodes at the two centers.In addition to examining rates by organism at multiple centers, publications on PD-related infections should also present the organism-specific data as rates, and not just as proportions or percentages of the total peritonitis rate. Table 3 shows an example of rates by organism.TABLE 2 Causes of Peritonitis 1 C ontamination, most likely skin or environmental o rganisms Contamination at the time of connection Contamination from tubing Hole in exchange tubing or catheter L oss of cap on end of tubing or failure to close clamp with leaking Product defects 2 C atheter related, most often staphylococcal species or Pseudomonas aeruginosa B iofilm on internal portion of the catheter (relapsing, repeat peritonitis) Exit-site and tunnel infection 3 B owel-source enteric organisms including gram-negative rods, Candida, and anaerobes Diverticulitis Cholecystitis Ischemic bowel ColitisPerforated stomach or intestine Colonoscopy, especially with polypectomy C onstipation with transmural migration of organisms into peritoneum 4 Bacteremia, often Streptococcus or Staphylococcus Transient from dental procedures Infection of intravascular device 5 G ynecologic source, often Streptococcus, Candida, some gram-negative rods Peritoneal vaginal leak Vaginal delivery Hysteroscopy by guest on July 22, 2014/Downloaded fromPDI NovEMBER 2011 - voL. 31, No. 6 ISPD: REDUCING THE RISKS OF PD-RELATED INFECTIONSthe potential benefit against the risk of vancomycin usehastening the emergence of resistant organisms.In patients participating in the U.S. National CAPDRegistry, catheter survival was superior for double-cuffcatheters compared with single-cuff catheters; double-cuff catheters were also less likely to result in catheter removal for exit-site infection (32). This benefit was not confirmed in a single-center randomized trial with a much smaller number of patients (33); however, a recent study from Canada found that double-cuff catheters were associated with lower rates of S. aureus peritonitis (12). A large multicenter randomized controlled trial (RCT) would be helpful to resolve this question.A downward-directed tunnel may decrease the risk of catheter-related peritonitis (34); however, randomized trials have not confirmed a benefit for the swan-neck configuration in reducing PD-related infections (29,30), nor has burying the catheter proved effective in reducing the risk of infection (35). Outcomes for infectious and mechanical complications are equivalent in cathetertypes using downward and lateral tunnel-tract and exit-site configurations (30).Every effort should be made to avoid trauma and hematoma during catheter placement. The exit siteshould be round, and the tissue should fit snugly around the catheter. Sutures at the exit site increase the risk of infection and are contraindicated. Some programs obtain nose cultures before placement of the catheter, and they treat positive S. aureus nasal carriage with a 5-day course of intranasal mupirocin. No data on the effectiveness ofthat approach are available. Once the catheter is placed,and until healing is complete, dressing changes should be done by a dialysis nurse using sterile technique. The exit site should be kept dry until well healed, which precludes showers or tub baths for that period, which can take up to 2 weeks or more.TRAINING PROGRAMS• Training methods influence the risk of PD infections (36–46). (Evidence)• Whenever possible, a nurse should provide the training, according to the 2006 ISPD guidelines/recommendations for PD patient training (Figure 1, Table 4), using the principles of adult education (38). (Opinion)• Each PD program should consult the ISPD guidelines/recommendations to prepare the trainer and to devel-op a specific curriculum for PD training. (Opinion)Each PD program should ensure that the trainer of the PD patients is well prepared and has the specifictheoretical and clinical skills to present a well-plannedCATHETER PLACEMENT TO PREVENT CATHETER INFECTIONS AND THE RELATED PERITONITIS EPISODES • No particular catheter has been definitively shown to be better than the standard silicone Tenckhoff catheter for the prevention of peritonitis (28–30). (Evidence)• Prophylactic antibiotics administered at the time of i nsertion decrease the infection risk (31). (Evidence)The topic of peritoneal access has been covered in a recent position paper (22) from the International Soci-ety for Peritoneal Dialysis (ISPD). Ideally, the patient should see the surgeon or training nurse (or both) before c atheter placement, with the ideal location for the exit site being determined. In addition, the patient shouldbe free from constipation. Proper skin preparation and careful cleansing of the area where the catheter is to beplaced is essential, and if there is an excess of hair, it may need to be removed. A single dose of intravenous (IV) antibiotic given at the time of catheter placement decreases the risk of subsequent infection. A first-generation cephalosporin has been most frequently used in that context. However, a randomized trial found that vancomycin (1 g IV, single dose) at the time of catheter placement is superior to cephalosporin (1 g IV, single dose) in preventing early peritonitis (31). The odds ratio of peritonitis without any antibiotic was 11.6, and for cefazolin (compared with vancomycin), it was 6.45. Eachprogram must therefore consider using vancomycin for prophylaxis for catheter placement, carefully weighing TABLE 3 Example of Rates by Organism Episodes per Organism year at risk Peritonitis Coagulase negative Staphylococcus 0.05 S. aureus peritonitis 0.03 Other gram-positive organisms 0.04 Pseudomonas aeruginosa 0.03 Other gram-negative organisms 0.10 Multiple organisms 0.02 Fungal 0.01 No growth/no culture 0.06 TOTAL 0.34Catheter infections (exit site, tunnel) S. aureus 0.05 P. aeruginosa 0.03 All others 0.12TOTAL 0.20 by guest on July 22, 2014/Downloaded fromPIRAINO et al. NovEMBER 2011 - voL. 31, No. 6 PDIcurriculum for the patient. The center should not assume that a nurse who knows how to do PD is prepared to train patients to do PD. When the learner is a patient with a chronic disease such as end-stage renal disease, that learner has special needs that require specific teaching techniques (42). Nurse education should include theories of adult education and the specifics for teaching adult patients on PD. A full discussion of adult learning is be-yond the scope of this position paper, but is described in some detail in the ISPD guidelines/recommendations for PD patient training at (38).Ideally, a senior mentor should train new PD nurses. That approach may require that new nurses be sent to train at a more experienced center. The old adage of “see one, do one, teach one” is not an appropriate foundation for the education of nurses in the principles of teaching PD. A structured nurse training program with subsequent continuing education is important to enhance the skills and the knowledge base of the trainers. A structured ap-proach can translate into high-quality patient training and good outcomes.Unfortunately, few if any studies have considered the nurse:patient ratio that leads to the best outcomes. Overburdening the nurse with excessive numbers of patients will result in shortened training times and dif-ficulty in scheduling retraining as needed. Ideally the PD nurse should be focused solely on home dialysis and should have no in-center hemodialysis responsibilities.The work group feels that, although the practice has notbeen adequately studied, the assignment of one nurseto fully train a particular patient rather than a differentnurse on different days should be adhered to, if possible.One-on-one training is ideal, although it may not alwaysbe feasible.Interestingly, the experience of the PD nurse may beless important than the training protocol (40). A retro-spective study paradoxically found that, compared withpatients trained by newer, less experienced nurses, thepatients trained by nurses with more experience hada shorter time to peritonitis. The authors speculatedthat nurses who had practiced PD for many years mayhave been more resistant to the institution of a pro-tocol using adult learning techniques that the centerhad i mplemented. Another explanation might be thatthe nurses with more experience had been assignedto train patients who were perceived to be more dif-ficult to train. The work group members feel that allnurses need continuous education to update and hone teaching skills.The center should have a clearly developed curricu-lum for PD training modeled after the ISPD guidelines/recommendations for PD patient training (38). This cur-riculum should include a daily plan for training content and handouts such as those that can be downloaded from the relevant article posted on the ISPD website. Hand hygiene must be emphasized. Training in the proper washing and drying of the hands, and use of hand dis-infectant, especially where the water supply is not to be trusted, are critical parts of the training (further detail provided later in this paper). At the end of training, the patient should be tested to ensure that learning of the objectives has occurred.Very few randomized trials have compared training protocols and curricula for PD patients. The length of patient training for PD is variable around the world (47). The length of training has never been shown to correlate with peritonitis rates. A trial that randomized centers to an enhanced training program using adult learning principles or to the center’s standard approach found that peritonitis rates were lower with the enhanced train-ing: 0.33 episodes per year (1 episode in 36.7 months) compared with 0.43 episodes per year (1 episode in 28.2 months) respectively (37). However, the details of the training curricula were not described, and the baseline peritonitis rates differed in the two groups. In children, peritonitis rates were lower in programs with longer training dedicated to theory and technical skills (39). No randomized trials have compared different training schedules that cover the same content and curriculum.TABLE 4 Suggestions for Retraining Frequency After hospitalizationAfter peritonitis or catheter infection After change in dexterity, vision, or mental acuity Three months after initial training and routinely thereafter(once yearly at minimum)Figure 1 — Center approach to peritoneal dialysis (PD) training. by guest on July 22, 2014/Downloaded fromPDI NovEMBER 2011 - voL. 31, No. 6ISPD: REDUCING THE RISKS OF PD-RELATED INFECTIONSAll patients must be taught what contamination is and what the proper response to contamination is. Each center should have a appropriate protocol to handle contamination (48). The protocol should detail the responses to specific occurrences such as fluid infused after the contamination and open compared with closed clamping of exchange tubing (36). Patients need to come to the center for a tubing change if the end of the tubing is contaminated. Prophylactic antibiotics should be pre-scribed if dialysis solution was infused after contamina-tion or if the catheter administration set was open and exposed to bacteria for an extended period of time. After a known break in technique, many nephrologists give a 2-day course of antibiotics; others provide a single dose of intraperitoneal antibiotic. There is no standard regi-men. Generally, a culture of the effluent is not obtained after an episode of contamination. However, if culturing is done and is positive, consideration might be given to extending therapy. After contamination, a positive culture in the presence of clear fluid and no symptoms should not be considered peritonitis; however, if left untreated, the patient might develop peritonitis. The goal of managing contamination is always to prevent the development of peritonitis.According to learning specialists, retraining plays an important role in reducing mistakes (41,43,44). Task repetition causes the brain to learn both the cognitive and the physical steps of the procedures. A psychological mechanism called “false memory” is readily illustrated by patients who perform an exchange in front of the nurse, but who are not aware of mistakes being made and who say that they were taught to perform the exchange that way (41). Memory is in a labile state after early exposure to new information; memory is enhanced by returning to the learning context and cues for correct performance (43,44).After a period of time, patients may alter the procedure they were taught during training. A study of compliance with the exchange procedure done at 6 months after the start of PD found that most patients had begun to take shortcuts or had simply veered off the prescribed steps that they had been carefully taught at the start of PD (46). Half the patients did not wash their hands according to procedure, nearly half did not check the bag for leaks, and 10% forgot to wear their mask or cap. Not wearing a mask or cap was associated with subsequent peritonitis risk in that study. However, other studies have not shown that using a mask reduces peritonitis risk (49,50). An Italian study of patient knowledge about PD (assessed using a questionnaire and a review of patient behavior during a home visit) found that, after a mean of 33 months on PD, 34% of patients did not answer the questions accurately, and 23% did not follow the correct exchange procedures (41). Noncompliance with exchange protocols was sig-nificantly associated with a higher peritonitis rate. These studies suggest a need for periodic retraining.Retraining seems to be helpful in reducing peritonitisrisk, but data are limited (41,45). Russo and colleagues (41) found retraining to be important for younger pa-tients (<55 years of age), patients with a lower educa-tion level, and patients in the early or late phase of PD therapy (<18 or >36 months). An observational study of120 dialysis centers in Italy found that retraining andhome visits correlated with lower peritonitis rates (45).How often a patient should be retrained or how soonafter initiation is unknown and requires study. Table 4shows our suggestions.A patient’s learning about the signs of peritonitis in training may be long forgotten if the patient does not develop their first peritonitis for several years and ifthere is no reinforcement of information on peritonitisgiven earlier. Retraining therefore needs to include notjust technique but also recognition of this important complication. The patient needs to be reminded that haziness of the effluent might be peritonitis even in the absence of pain, and that they should take that hazinessas an indication to call the dialysis unit.In the absence of definitive studies, each PD programmust decide when and how often to routinely retrain pa-tients. Retraining should include observation of dialysis exchange procedures, handwashing technique, recogni-tion of signs and symptoms of peritonitis, recognitionof contamination and the appropriate response to it,and exit-site care. Retraining is an opportunity to pre-vent future infections, with observation to identify thee mergence of problems such as poor vision, forgetful-ness, or shortcuts.Home visits by the PD nurse may be very useful in de-tecting problems with exchange technique, adherence to protocols, and other environmental and behavioral issuesthat increase the risk of infection and are best dealt with proactively. It has long been accepted that the locationfor exchanges must be clean, with avoidance of animalhair, dust-laden air, and fans or drafts. Home visits in-dicated that retraining was necessary in approximatelyone half of a center’s patients, who were not following protocols (41).CONNECTION METHODS• Spiking of dialysis bags is a procedure that poses ahigh risk for contamination of the system. “Flush be-fore fill” reduces the risk of contamination (51–58). (Evidence)by guest on July 22, 2014/Downloaded fromPIRAINO et al.NovEMBER 2011 - voL. 31, No. 6PDI• Data on peritonitis rates in automated PD (APD) and continuous ambulatory PD (CAPD) are conflicting (12,59–62). (Evidence)• The decision on modality (APD vs CAPD) should not be based on peritonitis risk. (Opinion)Data to show that spiking leads to peritonitis are abundant. Furthermore, for both CAPD and APD, flushing with dialysate before filling the abdomen has been shown to decrease the risk of peritonitis from contamination. Therefore, for CAPD, a double-bag system should be used. Manual spiking should be avoided as much as p ossible; if spiking is required, assist devices may be used. A systematic review concluded that of all catheter-related interventions designed to prevent peritonitis in PD, only disconnect (twin-bag and Y-set) systems have been proved to be effective (compared with conventional spike systems) (58). Close attention must therefore be paid to the connection methodology. For programs that switch vendors and, therefore, connection method, careful at-tention should be paid to subsequent infection rates. Peritonitis rates on APD and CAPD are probably similar (12,59,60). The literature describing the relative risks of peritonitis with continuous cycling PD (CCPD) and CAPD is conflicting, but the disparate results may reflect the fact that the cycler connection methodology varies from study to study and sometimes is not even mentioned in the paper (59). Several studies have shown that, compared with CAPD patients, CCPD patients have significantly lower peritonitis rates (61,62); however, use of a cycler that requires spiking may lead to high rates of peritonitis caused by contamination if an assist device is not used. The work group recommends either the use of an assist device, if available, for all spiking procedures or conver-sion to a system that does not require spiking. Some cyclers require a cassette; if the cassette is reused, the risk of peritonitis cause by water-borne organisms is high (63,64). Cassettes should not be reused. More research is needed comparing peritonitis risk in dry day, CCPD, and CAPD patients. Patients on nightly PD (cycler at night with a dry day) may have a decreased risk of infection compared with those on CCPD (cycler at night plus a day fill), perhaps because the empty abdomen for part of the day enhances immune function (65). This issue also requires further study.EXIT-SITE CARE TO PREVENT PERITONITIS• Prevention of catheter infections (and thus perito-nitis) is the primary goal of exit-site care. Antibiotic protocols against S. aureus are effective in reducing the risk of S. aureus catheter infections (66–81). (Evidence)• All PD patients should use topical antibiotic eitherat the catheter exit site or intranasally or both(66,70,71,73–76,78,82). (Evidence)• Topical antibiotic ointments (as opposed to antibiotic creams) should not be used at the exit site of polyure-thane catheters (82). (Evidence)Routine exit-site care by the patient begins when theexit site is well healed; such care is part of the patient’s training. Water and antibacterial soap are recommendedby many centers. Use of an antiseptic to clean the exitsite is preferred in some programs, but the agent must benon-cytotoxic. The concentration of the cleansing agentsmust be carefully considered (83–87). For example, povi-done iodine is cytotoxic at concentrations greater than0.001%; hydrogen peroxide, at greater than 0.003%; sodium hypochlorite, at greater than 0.24%; and chlor-hexidine, at greater than 0.005% (83,84).Excellent hand hygiene is most important before any examination of the patient’s exit site by the patient,family members, and members of the health care team.The U.S. Centers for Disease Control and Prevention recommends 70% alcohol-based hand rubs as the most effective hand cleansing agent (88). The quantity ap-plied to the hands should take at least 15 seconds ofhand rubbing to dry. Handwashing for 15 seconds with antimicrobial soap (4% chlorhexidine) is the next most effective method for hand cleansing. Visibly dirty hands require handwashing with soap. Polished nails doublethe risk of bacterial contamination on hands, and ar-tificial nails create a risk of bacterial contaminationthat is increased by a factor of 7 (88). Patients, healthcare givers, and patient helpers should all be aware ofproper hand hygiene protocols. If the water the patientuses is thought to have a high bacterial count, then theuse of alcohol hand hygiene is preferred to simply usingtap water.A number of protocols for the prevention of S. aureusPD-related infections have been examined. Prophylaxisusing daily application of mupirocin cream or ointmentto the skin around the exit site has been effective in reducing S. aureus exit-site infection and peritonitis ina number of reports (70,75,76,78,80,89). An observa-tional study in 740 incident PD patients showed that useof topical mupirocin was associated with a significant reduction in exit-site infection (0.168 vs 0.156 episodesper patient–year) and peritonitis (0.443 vs 0.339 epi-sodes per patient–year) (80). In a meta-analysis of ten studies (three RCTs and seven historical cohort studies)of mupirocin prophylaxis to prevent S. aureus infection,PD patients using prophylaxis had a 63% reduction in therisk of S. aureus infection—peritonitis being reduced by66% and exit-site infection by 62% (66). A more recentby guest on July 22, 2014/Downloaded from。

科技英语考试

第一题：填空1 科技英语的翻译标准是：准确规范，通顺易懂，简洁明晰2 科技英语的文体的特点：无人称句多，被动语态多，专业名词术语多,非谓语动词多，长句子多。

3 科英翻译的方法：直译与意译，合译与分译，增译与省译，顺译与倒译。

第二题：根据上下文选择词义翻译句子（develop）1 Packaged software is developed to serve the specific needs of one user.软件包的开发只是为某一用户的特定需要服务2 Noises may develop in a worn engine.磨损了的引擎里可能会产生各种噪音。

3 Shorts frequently develop when insulation is worn.绝缘被磨坏时往往会发生短路。

4 Sure enough,80 percent of the plants developed the disease.果然，80%的庄稼都染上了这种病。

5 Other isolation methods are being developed.目前正在研究其他隔离方法。

6 In developing the design, we must consider the feasibility of processing.在进行设计时，必须考虑加工的可能性。

7 After the war much of this knowledge was poured into the developing of the computers..战后，这项知识大量地应用于研制计算机。

8 They cited cases of identical twins reared in different homes who developed very different characteristics despite identical heredity.他们列举了一些这样的事例：在不同的家庭抚养的一对双胞胎尽管遗传特征完全相同，但会显示出完全不同的个性。

初三英语完形填空深度理解单选题60题

初三英语完形填空深度理解单选题60题1. In the classic novel, the character was in a dilemma. He had to ______ between staying with his family and pursuing his dream.A. chooseB. selectC. electD. pick答案：A。

解析：choose是普通用词，侧重根据个人意愿和判断从众多的对象中进行选择，这里表达在家庭和梦想之间做出选择，比较通用。

select较正式，强调经过认真考虑后的挑选，通常是从多个类似事物中进行挑选，在这里语境没有那么正式。

elect主要用于选举，是选举某人担任某职位，不符合语境。

pick通常用于口语，有挑选、采、摘等意思，不如choose正式且常用于这种两难抉择的语境。

2. The scientific article mentioned that the new species ______ a unique feature that distinguishes it from others.A. hasB. ownsC. possessesD. holds答案：C。

解析：possess表示拥有，常指拥有抽象的东西，如品质、特征等，这里说新物种拥有独特的特征，用possess最合适。

has 是最普通的表示“有”，比较口语化。

own强调合法地拥有某物，多指所属关系，如拥有财产等，这里不是指所属关系。

hold表示握住、持有（具体东西）或者举行（会议等），不符合这里表示拥有特征的语境。

3. In the adventure story, the hero ______ his courage when facing the dangerous situation.A. showedB. displayedC. exhibitedD. demonstrated答案：A。

甲苯-2,4-二异氰酸酯与仲胺类化合物反应中的质子转移过程

[Article]物理化学学报(Wuli Huaxue Xuebao )Acta Phys.-Chim.Sin .2014,30(1),34-42JanuaryReceived:July 15,2013;Revised:November 12,2013;Published on Web:November 12,2013.∗Corresponding author.Email:wangml@;Tel:+86-755-26558105.The project was supported by the National Defense Foundation of China (973)(613142),National Natural Science Foundation of China (20673073),and Foundation of Shenzhen Key Laboratory of Functional Polymer,China (FP20130007).国防973(613142),国家自然科学基金(20673073),深圳市功能高分子重点实验室开放基金(FP20130007)资助项目©Editorial office of Acta Physico -Chimica Sinicadoi:10.3866/PKU.WHXB 201311121甲苯-2,4-二异氰酸酯与仲胺类化合物反应中的质子转移过程王晓轩1胡伟2贵大勇1池旭辉2王明良1,*田德余1刘剑洪1马新刚2庞爱民2(1深圳大学化学与化工学院,广东深圳518060;2湖北航天化学技术研究所,湖北襄樊441003)摘要:采用密度泛函理论B3LYP/6-31+G(d ,p )方法研究了甲苯-2,4-二异氰酸酯(2,4-TDI)与仲胺类化合物反应过程中的质子转移效应.研究发现甲醇分子对反应有显著的催化效应,可使反应能垒大幅降低,这表明含活泼氢的化合物会加速质子转移过程,从而加快反应速率.2,4-TDI 与甲基-N -甲基氨基甲酸酯的催化加成反应为一步反应,其反应过渡态呈六元环结构;而2,4-TDI 与N -甲基对硝基苯胺、二苯胺、1,2-二氢-2,2,4-三甲基喹啉等芳香胺类化合物的催化加成反应经历了两步反应,其中第一步为速率控制步骤.研究表明,在与2,4-TDI 的反应中,芳胺化合物的活性高于甲基-N -甲基氨基甲酸酯的活性,计算的反应活性顺序与实验结果一致.关键词:密度泛函理论;质子转移;甲苯-2,4-二异氰酸酯;聚氨酯反应中图分类号:O643.12Proton Transfer in Reaction between 2,4-Diisocyanatotoluene and Amine CompoundsWANG Xiao-Xuan 1HU Wei 2GUI Da-Yong 1CHI Xu-Hui 2WANG Ming-Liang 1,*TIAN De-Yu 1LIU Jian-Hong 1MA Xin-Gang 2PANG Ai-Min 2(1College of Chemistry and Chemical Engineering,Shenzhen University,Shenzhen 518060,Guangdong Province,P .R.China ;2Hubei Institute of Aerospace Chemotechnology,Xiangfan 441003,Hubei Province,P .R.China )Abstract:The effects of proton transfer on the reaction between 2,4-diisocyanatotoluene (2,4-TDI)and active-hydrogen-containing amine compounds were calculated using density functional theory (DFT)at the B3LYP/6-31+G(d ,p )level.The energy barriers are significantly reduced when a methanol molecule serves as a proton transporter or a reactive catalyst,indicating that the labile hydrogen-containing compound plays a key role in accelerating the reaction rate and proton transfer.The catalytic addition of 2,4-TDI and methyl N -methylcarbamate follows a one-step mechanism,with a transition state characterized by a six-membered ring.However,the catalytic additions of 2,4-TDI and aromatic amines such as N -methyl-p -nitroaniline,diphenylamine,and 1,2-dihydro-2,2,4-trimethylquinoline involve two steps,with the first step as the rate-limiting step.The reactions between 2,4-TDI and aromatic amines have lower energy barriers than that between 2,4-TDI and methyl N -methylcarbamate.The aromatic amines are more active than methyl N -methylcarbamate in the reaction with 2,4-TDI,which is in a good agreement with experimental results.Key Words:Density functional theory;Proton transfer;2,4-Diisocyanatotoluene;Urethane formation1IntroductionPolyurethane materials are widely used in industry,aviation,shipping,and building construction in modern life.1Polyure-thanes are derived from isocyanates and alcohols in the pres-ence of reactive catalysts such as urea,2,3amino 4-6or hydroxyl 7-9groups.To improve the properties of the materials,additives34WANG Xiao-Xuan et al.:Proton Transfer in Reaction between2,4-Diisocyanatotoluene and Amine Compounds No.1were added into the reaction for stabilizing or scorch-inhibit-ing.10The investigation of reaction mechanism in multi-compo-nent urethane formation system is important for the production of purpose specific polyurethane materials.Since the reactions are quite complicated,the detailed reaction mechanism is still an open question.11The additions between isocyanates and alcohols are the main reactions in urethane formation.As the labile hydrogen of alcohol molecule transfers from the hydroxyl to the isocy-anate with the new C―O bond forming,urethane linkage RO(CO)NHR¹is formed.The urethane linkage has been report-ed to be a catalyst for the urethane formation by Ephraim12and Arnold13et al.,and the catalytic effect has been estimated in our previous work.14Similar to the alcohols,the urethane link-age RO(CO)NHR¹contains labile hydrogen on the amino, which can also react with isocyanate.Therefore,the addition between isocyanates and RO(CO)NHR¹linkage can become the dominant reaction in the cross-linking process of late reac-tion stage.However,the mechanisms of the reaction between isocyanates and RO(CO)NHR¹are not well studied.The commonly used amine additives containing labile hydro-gen on the amino can also react with the isocyanates.N-methyl-p-nitroaniline is widely used as blocking agents to prepare blocked isocyanates which are preferred in a typical heat-curable system.15 Upon heating,the fragile bond of the blocked isocyanates breaks and the isocyanates as well as N-methyl-p-nitroaniline are regener-ated.In addition,N-methyl-p-nitroaniline is also used as a thermal stabilizer in smokeless propellant.16Diphenylamine derivatives are commonly used as additives in the manufacture of polyurethanes to inhibit scorching in polyurethane foam.10,17Diphenylamine de-rivatives containing an active hydrogen may also react with isocy-anates to form urea products.1,2-Dihydro-2,2,4-trimethylquino-line(TMQ)is another aniline compound which is used as an anti-oxidant or antidegradant in producing urethane rubber and ny-lon.18,19Similar to diphenylamine,TMQ can also react with isocya-nates as it contains an active hydrogen.The urethane formations between isocyanates and alcohols have been studied by both experimental12,13,20,21and theoretical22-27 methods.Arnold et al.13pointed out that the reactions between2,4-diisocyanatotoluene(2,4-TDI)and methanol would exhibit anom-alous kinetics rather than the simple second-order relationship in the presence of other nucleophilic reagents,such as amines and their nucleophilic reaction products.Raspoet et al.25suggested that methanol dimer and trimer are involved in the reaction between isocyanic acid and methanol.Samuilov et al.22-24studied the reac-tion of methyl isocyanate with linear methanol associates at the B3LYP/6-311++G(df,p)level and found that the activity of the re-acting system increases with the degree of methanol association. The above works indicate that there exists a self-catalytic effect in the reactions between the isocyanates and the alcohols.In our pre-vious work,14Density functional theory(DFT)approach was car-ried out to study the proton transfer effects on the urethane forma-tion between2,4-TDI and methanol at the B3LYP/6-311G(d,p) level.The energy barriers of the reactions are significantly re-duced with diphenylamine and methyl N-methylcarbamate mole-cule serving as a reactive catalyst.Moreover,all labile hydrogen-containing compounds play a key role in accelerating the reaction rate and the proton transfer.However,the reaction mechanism and reaction activity between isocyanate and amino groups are still not clear so far.DFT28,29is an effective approach to estimate molecular spec-trum,30investigate electron transfer,31evaluate binding energy,32 and study reaction mechanism.33In this paper,DFT approach was implemented to study the reaction between2,4-TDI and labile hydrogen-containing amine compounds.Methyl N-methyl-carbamate molecule was used to model the urethane linkage RO(CO)NHR¹for the saving of computational cost.The direct additions between2,4-TDI and methyl N-methylcarbamate,N-methyl-p-nitroaniline,diphenylamine as well as TMQ were the-oretically examined and the catalytic mechanisms were also in-vestigated with methanol serving as a proton transporter.The geometries of transition state,pre-reaction complex,and post-reaction complex were first optimized.Based on the optimized geometry,the energy barriers were then estimated.In addition, the charge populations were calculated by the natural bond or-bital(NBO)analysis.2Computational detailsAll the electronic structure calculations in this study were performed using the Gaussian09suit of programs.34The densi-ty functional theory with B3LYP/6-31+G(d,p)basis set35was used to optimize the geometries of the reactants,intermediates, transition states(TS),and products.Frequency analysis was used to verify the optimized geometries of TS,which are char-acterized by one imaginary frequency(IF)and stationary points with no imaginary frequency.36-38The intrinsic reaction coordinate(IRC)calculation was carried out to check the ener-gy profile connecting each TS to the two associated minima of the proposed mechanism.39Natural bond orbital analyses were also performed for all the optimized geometries to show the charge change in the proton transfer process.403Results and discussionThe optimized geometries of2,4-TDI,methanol,methyl N-methylcarbamate,N-methyl-p-nitroaniline,diphenylamine,and TMQ are presented in Fig.1.As listed in Table1,the corre-sponding energies were computed to estimate the energy barri-er of the reactions.3.1Reaction between2,4-TDI and methyl N-methylcarbamate3.1.1Direct addition between2,4-TDI and methyl N-methylcarbamateThe reaction mechanism of direct addition between2,4-TDI and methyl N-methylcarbamate is the same as that of the reac-tion between2,4-TDI and methanol.14As shown in Fig.2,the stable intermediate1is first formed between2,4-TDI and meth-35Acta Phys.-Chim.Sin .2014V ol.30yl N -methylcarbamate.Because of the three hydrogen bonds,N4―H3…N2(0.244nm),C5―H6…O7(0.267nm),and C8―H9…O10(0.264nm),the total energy of the intermediate 1is lowered by 8.79kJ ∙mol -1in comparison with separated reac-tants.The amino group of the methyl N -methylcarbamate inter-acts with the N ＝C bond of the isocyanate and the transition state TS2characterized by a four-membered ring is formed.Due to the strong steric effect of the four-membered ring,the energy of TS2lies 151.73kJ ∙mol -1above the energy of the sep-arated reactants,and the energy barrier of the reaction comes out to be 160.52kJ ∙mol -1as presented in Table 2.In addition,H3of amino group of methyl N -methylcarbamate possesses 0.511(atomic charge)which is larger than 0.5,it indicates that the reaction involves the proton transfers from amino group to the isocyanate group of 2,4-TDI.With the proton H3transfer,the new N2―H3and C1―N4bonds form and the old N4―H3bond breaks.Finally the urethane product 5is formed.With no catalyst,the direct addition between 2,4-TDI and methyl N-Compound name 2,4-TDI methanolmethyl N -methylcarbamate N -methyl-p -nitroaniline diphenylamine1,2-dyhidro-2,2,4-trimethylquinolineTotal energy/hartree-606.564-115.735-323.775-531.455-518.691-521.107Fig.1Optimized geometries of (a)2,4-TDI,(b)methanol,(c)methyl N -methylcarbamate,(d)N -methyl-p -nitroaniline,(e)diphenylamine,and (f)1,2-dyhidro-2,2,4-trimethylquinolineThe data with no brackets stand for bond lengths (nm);the data within brackets stand for the atomic NBO charges (e ).Table 1Total energies of 2,4-TDI,methanol,methyl N -methylcarbamate,N -methyl-p -nitroaniline,diphenylamine,and 1,2-dyhidro-2,2,4-trimethylquinoline in gas phaseFig.2Profile for the relative energy of direct addition between 2,4-TDI and methyl N -methylcarbamateThe data with no brackets stand for bond lengths (nm);the data within brackets stand for the atomic NBO charges (e ).The data with or without brackets stand forthe same meanings in Figs.3-9.36WANG Xiao-Xuan et al .:Proton Transfer in Reaction between 2,4-Diisocyanatotoluene and Amine CompoundsNo.1methylcarbamate shows a high energy barrier of 160.52kJ ∙mol -1,which indicates that the reaction can hardly occur at room temperature.3.1.2Addition between 2,4-TDI and methyl N -methylcarbamate with one methanol as a catalyst As the reaction between 2,4-TDI and methanol happens via self-catalysis,14the alcohols may catalyze the reaction between 2,4-TDI and methyl N -methylcarbamate in the system of ure-thane formation.Methanol molecules were used to evaluate the catalytic effect on the side reactions between 2,4-TDI and amine compounds.With the three strong hydrogen bonds (N6―H5…O4(0.197nm)and O4―H3…N2(0.213nm)as well as C7―H8…O9(0.250nm))between 2,4-TDI,methanol and methyl N -methylcar-bamate,the stable intermediate 4firstly forms as illustrated in Fig.3.The energy of intermediate 4is largely reduced by 31.74kJ ∙mol -1in comparison with the separated reactants.As the reaction proceeds,the transition state TS5characterized by a six-mem-bered ring is formed between the reactants and methanol mole-cule,where the hydrogen atoms H3and H5are obviously shared by the N2of isocyanate,O4of hydroxy group,and N6of the ami-no group.The transition state TS5lies 62.80kJ ∙mol -1above the energy of the separated reactants.The IRC path calculation showsthat H5first transfers from N6of the amino to O4of the hydroxy of methanol,meanwhile H3transfers from O4to N2of the isocya-nate group,then the new N ―H and C ―O bonds form.Following the proton transfer,product intermediate 6stabilized by two hydro-gen bonds forms as shown in Fig.3.In comparison with the energy of pre-association complex 4,the energy barrier of the catalytic reaction is estimated to be 94.54kJ ∙mol -1as illustrated in Table 2.Obviously,the energy barrier is largely reduced by including a methanol molecule,which shows hugely catalytic effect on the proton transfer.The methanol molecule serves as a proton donor to the isocyanate group and a proton acceptor to the amine.With a methanol mol-ecule serving as a proton transporter,the reaction rate between 2,4-TDI and methyl N-methylcarbamate is significantly accel-erated.However,the energy barrier of 94.54kJ ∙mol -1is still much higher than that of the catalytic reaction (51.41kJ ∙mol -1)between 2,4-TDI and alcohols.14This indicates that the cross-linking reaction between 2,4-TDI and methyl N -methylcarba-mate in urethane formation mainly occurs in the late stage of the reaction process when the alcohols are largely consumed.3.2Reaction between 2,4-TDI and N -methyl-p -nitroanilineIn the polyurethane industry,N -methyl-p -nitroaniline is com-monly used as blocking agents to prepare blocked isocyanates,which are preferred in a typical heat-curable system.N -methyl-p -nitroaniline is a kind of aromatic amine with a hydrogen at-om on the amino group which can react with the isocyanate group of 2,4-TDI.3.2.1Direct addition between 2,4-TDI and N -methyl-p -nitroanilineAs displayed in Fig.4,the calculations show that the hydro-gen bond N4―H3…N2(0.237nm)and the weak hydrogen bond C5―H6…N4(0.286nm)first form between the 2,4-TDI and N -methyl-p -nitroaniline which make the pre-association complex 7stable with an energy of -6.78kJ ∙mol -1comparedTable 2Energy barriers for the reactions between 2,4-TDI and amines in gas phaseReaction TDI+methyl N -methylcarbamate TDI+N -methyl-p -nitroaniline TDI+diphenylamine TDI+TMQCatalyst no methanolno methanol no methanol no methanolTS (step I)TS2TS5TS8TS11TS16TS19TS24TS27Energy barrier (kJ ∙mol -1)160.5294.54143.1455.10136.9157.36131.7546.02TS (step II)TS13TS21TS29Energy barrier (kJ ∙mol -1)31.4022.6924.33Fig.3Profile for the relative energy of addition between 2,4-TDI and methyl N -methylcarbamate with one methanol as acatalyst37Acta Phys.-Chim.Sin .2014V ol.30to the separated reactants.Similar to the direct reaction be-tween 2,4-TDI and methyl N -methylcarbamate,the transition state TS8is featured by a four-membered ring.Due to the strong steric effect of the four-membered ring,the transition state TS8lies 136.36kJ ∙mol -1above the reactants.With the proton transfer from the amino to the isocyanate group,the product complex 9is yielded,which lies -43.33kJ ∙mol -1be-low the energy of the separated reactants.The energy barrier of direct addition between 2,4-TDI and N -methyl-p -nitroaniline finally reaches 143.14kJ ∙mol -1com-pared to the energy of the pre-association intermediate 7as list-ed in Table 2.3.2.2Addition between 2,4-TDI and N -methyl-p -nitroaniline with one methanol as a catalystSimilar to the catalytic reaction of 2,4-TDI and methyl N -methylcarbamate,the addition between 2,4-TDI and N-methyl-p -nitroaniline may also be catalyzed by an active hydrogen-containing compound such as methanol.IRC path calculations were performed to the catalytic reaction between 2,4-TDI and N-methyl-p-nitroaniline,the process of the reaction shows dif-ferences.The catalytic reaction comes out to be a two-step re-action as shown in Fig.5.A pre-association complex 10is first formed between 2,4-TDI,methanol and N-methyl-p -nitroaniline.As depicted in Fig.5,a hy-drogen-bond network is formed,which is composed of the O4―H3…N2(0.218nm),the N6―H5…O4(0.200nm),and the C7―H8…O9(0.275nm)hydrogen bonds.Due to the strong hydrogen-bond network,the energy of structure 10is reduced by 37.89kJ ∙mol -1.With the breaking of the weak hydrogen bond C7―H8…O9,the isocyanate,amino,and hydroxyl groups lie in the same plane and the TS11with one imaginary frequency forms.TS11contains two strong hydrogen bonds,the O4―H3…N2(0.188nm)and the N6―H5…O4(0.189nm).Even though the energy of the structure can decrease owing to the formation of the hydro-gen bonds,the total energy of TS11is still increased by 55.10kJ ∙mol -1compared to structure 10due to the strong steric effect.As the reaction proceeds,the intermediate 12forms.The energy of structure 12is slightly lowered by 2.72kJ ∙mol -1due to the much tighter hydrogen bonds of O4―H3…N2(0.185nm)and N6―H5…O4(0.180nm).Intermediate 12is verified to be stable mini-ma with no imaginary frequency.In the second step of the reaction,transition state TS13featured by a six-membered ring was formed with the two hydrogen atoms H3and H5shared by N2of the isocyanate and O4of the hydroxy group as well as N6of the amino,which gives rise to an energy barrier of 31.40kJ ∙mol -1as listed in Table 2.By the analysis of the vibrational mode of TS13at the imaginary frequency and the IRC calculations,one found that the proton H3transfers from O4to N2,meanwhile the H5from N6to O4.With the proton transfer along the hydrogen-bond network,the N6of the amino group moves to the C1of the isocyanate,the new C ―N bond forms,and the product complex 14is yielded as shown in Fig.5.In the addition between 2,4-TDI and N -methyl-p -nitroani-line with one methanol as a catalyst,the energy barrier of the first step is 55.10kJ ∙mol -1while that of the second step is 31.40kJ ∙mol -1.It is clearly that the first step is the rate-limit-ing step in the whole process of the reaction.3.3Reaction between 2,4-TDI and diphenylamine Diphenylamine derivatives are commonly used as additives in the manufacture of polyurethanes to inhibit scorching.Di-phenylamine is also a kind of aromatic amine with a hydrogen atom on the amino group which may react with 2,4-TDI as N -methyl-p -nitroaniline.3.3.1Direct addition between 2,4-TDI anddiphenylamineThe mechanism of direct addition between 2,4-TDI and di-phenylamine is the same as that of reaction between 2,4-TDI and N -methyl-p -nitroaniline.As shown in Fig.6,a four-mem-bered ring is formed between the two reactant molecules with the hydrogen atom H3shared by N2of the isocyanate groupFig.4Profile for the relative energy of direct addition between 2,4-TDI and N -methyl-p-nitroaniline38WANG Xiao-Xuan et al .:Proton Transfer in Reaction between 2,4-Diisocyanatotoluene and Amine CompoundsNo.1and N4of the amino.An energy of 130.25kJ ∙mol -1of the opti-mized structure of TS16is estimated in comparison with the separated reactants.A high energy barrier of 136.91kJ ∙mol -1is obtained for the direct reaction between 2,4-TDI and diphenyl-amine as listed in Table 2.3.3.2Addition between 2,4-TDI and diphenylamine withone methanol as a catalystThe catalytic reaction between 2,4-TDI and diphenylamine has been reported in the previous work.14However,the reac-tion was found to be a two-step reaction by a more detailed cal-culation as depicted in Fig.7.Starting from the prereaction complex 18,TS19characterized by one imaginary frequency is formed.Structure 19contains two strong hydrogen bonds O4―H3…N2(0.189nm)and N6―H5…O4(0.191nm),the isocya-nate,amino and hydroxy groups lie in a same plane.The IRC calculations reach the intermediate 20,the product of the first step reaction.The energy of 19.93kJ ∙mol -1is evaluated for the complex 20,which is 4.06kJ ∙mol -1lower than that of TS19.As the reaction continues,transition state TS21is formed with a relative energy of 42.62kJ ∙mol -1.The H3and H5in the six-membered ring are shared by the three reactants.The vibra-tional mode of TS21at the imaginary frequency shows that the proton H3transfers from O4to N2,meanwhile the H5from N6to O4.With the proton transfer along the hydrogen-bondFig.5Profile for the relative energy of addition between 2,4-TDI and N -methyl-p-nitroaniline with one methanol as a catalystFig.6Profile for the relative energy of direct addition between 2,4-TDI anddiphenylamine39Acta Phys.-Chim.Sin .2014V ol.30network,N6of the amino group and C1of the isocyanate get closer and form a new C ―N bond,and finally the product complex 22is yielded.In the catalytic addition between 2,4-TDI and diphenylamine,the first step is the rate-limiting step in the whole reaction with the energy barrier of 57.36kJ ∙mol -1compared to 22.69kJ ∙mol -1of the second step.3.4Reaction between 2,4-TDI and TMQ3.4.1Direct addition between 2,4-TDI and TMQWith the same mechanism as that of reaction between 2,4-TDI and N-methyl-p -nitroaniline,the direct addition between 2,4-TDI and TMQ experiences a four-membered transition state 24with the H3shared by the isocyanate and amino groups as shown in Fig.8.The energy of TS24is estimated to be 128.74kJ ∙mol -1compared to the separated reactants and the energy barrier of the direct reaction comes out to be 131.75kJ ∙mol -1.3.4.2Addition between 2,4-TDI and TMQ with onemethanol as a catalystSimilar to the catalytic reaction of 2,4-TDI and N -methyl-p -ni-troaniline,the catalytic addition between 2,4-TDI and TMQ also goes through two stages as shown in Fig.9.At the beginning of the reaction,a pre-association complex 26between 2,4-TDI,metha-nol and TMQ is first formed.The energy is lowered by 27.26kJ ∙mol -1as a result of the formation of three hydrogen bonds O4―H3…N2(0.214nm)and N6―H5…O4(0.211nm)as well as C7―H8…O4(0.261nm).As the reaction proceeds,transition state 27is obtained.In TS27,the isocyanate,amino and hydroxyl group are in a same plane and the energy rises up to 18.76kJ ∙mol -1.By running the IRC calculation,the product of the first step is opti-mized as complex 28with two strong hydrogen bonds of O4―H3…N2(0.200nm)and N6―H5…O4(0.185nm)as well as theatomic attraction between C1of the isocyanate and N6of the ami-no group.The energy of complex 28is reduced by an energy of 11.93kJ ∙mol -1in comparison with that of TS27.Starting from the intermediate 28,the transition state 29of the second stage is char-acterized by a six-membered ring with the two hydrogen atoms H3and H5shared by N2of the isocyanate and O4of the hydroxy as well as N6of the amino group.With H3transfer from O4to N2and H5from N6to O4,the product complex 30forms finally.In the catalytic addition between 2,4-TDI and TMQ,the first step is the rate-limiting step with the energy barrier of 46.02kJ ∙mol -1compared to 24.33kJ ∙mol -1of the second step.As listed in Table 2,the direct additions between 2,4-TDI and methyl N -methylcarbamate,N -methyl-p -nitroaniline,di-phenylamine as well as TMQ show high energy barriers of 160.52,143.14,136.91,and 131.75kJ ∙mol -1,respectively.The methanol catalytic reaction between 2,4-TDI and methyl N -methylcarbamate follows a one-step mechanism with an ener-gy barrier of 94.54kJ ∙mol -1,while the catalytic additions be-tween 2,4-TDI and aromatic amines such as N -methyl-p -ni-troaniline,diphenylamine as well as TMQ follow a two-step re-action.With the first-step as the rate-limiting step,and the ener-gy barriers come out to be 55.10,57.36,and 46.02kJ ∙mol -1correspondingly,which is in a good agreement with the experi-mental activation energy of 28.5141or 38.1042kJ ∙mol -1.The results show that the aromatic amines are more active than methyl N -methylcarbamate in the reaction with 2,4-TDI,which is consistent with experiment.434ConclusionsThe reaction between 2,4-TDI and labile hydrogen-contain-Fig.7Profile for the relative energy of addition between 2,4-TDI and diphenylamine with one methanol as acatalyst40WANG Xiao-Xuan et al .:Proton Transfer in Reaction between 2,4-Diisocyanatotoluene and Amine CompoundsNo.1ing amine compounds in urethane formation was investigated by using DFT calculations at B3LYP/6-31+G(d ,p )level.The direct addition between 2,4-TDI and methyl N -methylcarba-mate,N -methyl-p -nitroaniline,diphenylamine as well as 1,2-dyhidro-2,2,4-trimethylquinoline can hardly occur because of the high energy barrier.In the case of methanol catalytic addi-tion between 2,4-TDI and methyl N -methylcarbamate,the reac-tion follows one-step mechanism with a transition state charac-terized by a six-membered ring and the energy barrier is low-ered to 94.54kJ ∙mol -1.However,the catalytic additions be-tween 2,4-TDI and aromatic amines such as N -methyl-p -ni-troaniline,diphenylamine as well as 1,2-dyhidro-2,2,4-trimeth-ylquinoline follow a two-step reaction.With the first-step as the rate-limiting step,the energy barrier is significantly reduced.The aromatic amines are more active than methyl N -methylcarba-mate in the reaction with 2,4-TDI,which is consistent with ex-Fig.9Profile for the relative energy of addition between 2,4-TDI and 1,2-dyhidro-2,2,4-trimethylquinoline with one methanol as acatalystFig.8Profile for the relative energy of direct addition between 2,4-TDI and1,2-dyhidro-2,2,4-trimethylquinoline41Acta Phys.-Chim.Sin.2014V ol.30periment.The results indicate that compounds with labile hy-drogen play an important role in accelerating the reaction rate and proton transfer.References(1)Silva,A.L.;Bordado,J.C.Catal.Rev.:Sci.Eng.2004,46,31.doi:10.1081/CR-120027049(2)Kimock,M.J.;Listemann,M.L.N,N,Nʹ-trimethylbis(Aminoethyl)Ether Substituted Urea Compostions for theProduction of 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琥珀防写课文英语作文300字

琥珀防写课文英语作文300字The Enigmatic Allure of Amber.Within the realm of precious gemstones, amber holds a captivating allure, captivating the imagination of collectors, historians, and scientists alike. Its ethereal beauty and remarkable properties have earned it a place of distinction, weaving a rich tapestry of tales andscientific insights.A Glimpse into Time.Amber, fossilized tree resin, is an organic gemstone that offers a unique window into the past. Formed millions of years ago, amber encapsulates remnants of ancient life, preserving a diverse array of flora and fauna in its golden depths. These inclusions, ranging from insects and spiders to plant material and even feathers, provide invaluable clues about the Earth's prehistoric ecosystems.The Enchantment of Beauty.Amber's alluring beauty stems from its warm, inviting hues. Its translucent nature allows light to dance and shimmer within its depths, creating an ethereal glow. The myriad shades of amber, from honeyed gold to deep cognac, lend themselves to exquisite jewelry, ornaments, and art objects.Medicinal Marvel.Beyond its aesthetic appeal, amber possesses reputed medicinal properties. For centuries, it has been revered as a natural healer, believed to alleviate pain, reduce inflammation, and enhance the body's immune response. Modern science is exploring the potential of amber's anti-inflammatory and antioxidant compounds, providing a glimpse into its therapeutic applications.Cultural Significance.Amber has left an enduring imprint on human culturesthroughout history. In ancient Greece, it was associated with the sun god Apollo and believed to bring good luck. The Romans prized amber for its medicinal properties, while the Baltic regions have long been renowned for their rich amber deposits, shaping the lives and economies of the people.Science and Serendipity.The scientific study of amber has unveiled afascinating world of chemical and physical properties. Its complex composition includes succinic acid, a valuable organic compound with applications in pharmaceuticals and other industries. Additionally, amber's electrostatic properties allow it to attract small objects, a phenomenon that has fascinated scientists and sparked imaginativetales of its magical allure.The Alluring Enchantress.Amber continues to captivate and inspire, its multifaceted nature enchanting people from all walks oflife. Its beauty, historical significance, and potential medicinal properties make it a timeless treasure. As we delve deeper into the secrets of this enigmatic gemstone, we uncover a testament to the wonders of nature and the enduring allure of the unknown.。

thematic proto-roles and argument selection

Thematic Proto-Roles and Argument SelectionDavid DowtyOhio State UniversityAs a novel attack on the perennially vexing questions of the theoretical status of thematicroles and the inventory of possible roles, this paper defends a strategy of basing a accountsof roles on more unified domains of linguistic data than have been used in the past tomotivate roles, addressing in particular the problem of argument selection(principlesdetermining which roles are associated with which grammatical relations). It is concludedthat the best theory for describing this domain is not a traditional system of discrete roles(Agent, Patient, Source, etc.) but a theory in which the only roles are two cluster-conceptscalled Proto-Agent and Proto-Patient, each characterized by a set of verbal entailments:an argument of a verb may bear either of the two proto-roles (or both) to varying degrees,according the number of entailments of each kind the verb gives it. Both fine-grained andcourse-grained classes of verbal arguments (corresponding to traditional thematic roles andother classes as well) follow automatically, as do desired "role hierarchies". By examiningoccurrences of the "same" verb with different argument configurations (e.g. two forms ofpsych predicates and object-oblique alternations as in the familiar spray/load class), it canalso be argued that proto-roles act as defaults in the learning of lexical meanings. AreProto-Role categories manifested elsewhere in language or as cognitive categories? If so,they might be a means of making grammar acquisition easier for the child, might explaincertain other typological and acquisitional observations, and may lead to an account ofcontrasts between unaccusative and unergative intransitive verbs that does not rely onderiving unaccusatives from underlying direct objects.1. IntroductionThere is perhaps no concept in modern syntactic and semantic theory which is so often involved in so wide a range of contexts, but on which there is so little agreement as to the nature and definition of the concept, as thematic role(or thematic relation) and its derivative,theta-role in Government-Binding Theory (GB). In addition to the "argument-indexing function in GB (see below), thematic roles have been invoked in the statement of multifarious syntactic generalizations in that and in other syntactic theories, and the existence of thematic roles is so taken for granted that psycholinguists now attempt to study their role in mental processing experimentally (Carlson and Tanenhaus 1988, Stowe 1989), and an introductory text in formal semantics (Chierchia and McConnell-Ginet 1990) offers a technique for formalizing roles while presupposing their necessity in a linguistic theory.Yet apart from some syntactic correlates of thematic roles, there is in fact a notable absence of consensus as to what thematic roles are (cf. below). At best, they are obviously creatures of the syntax-semantics interface, and thus require a sound semantic theoretical basis as well as a syntactic one (and mutually consistentones) in order to be considered respectable parts of a linguistic theory. But at worst, appeal to them can be a confusion of notions from the syntactic, semanticand pragmatic domains, or a "thinly disguised wild card to meet the exigencies of syntax" (Jackendoff 87:371). Despite the mention of Thematic roles in the Chierchia and McConnell-Ginet text, they have hardly been studied at all informal semantics1, which seems to have gotten by up to this point without any significant purpose for them to serve. Ray Jackendoff, the only semanticist whohas studied the concept extensively (non-model-thoeretically) and who is rituallycited by syntacticians at their first mention of the notion, has evolved a detailed understanding of thematic roles within his own theoretical framework (Jackendoff 1972, 1976, 1983, 1987) that is clearly quite different from and inconsistent withthat of GB or of many current syntacticians (Jackendoff 1987).Though the term thematic relation(later role) was introduced by Gruber (1965) andmade widely known by Jackendoff (1972), as semantic categories they obviously corresponded to a great extent to the (semantic)Deep Cases of Fillmore’s contemporaneous Case Grammar (1966, 1968) --- and this in turn harks back toideas of structuralists such as Frank Blake (1930), and ultimately to Panini’s karakas--- but Deep Cases played a quite different part within his theory fromthat of thematic roles for Gruber-Jackendoff or Ú-Roles do in GB. Chomsky (1981: 35), in introducing Ú-roles into GB and citing precedents for the idea, claimed thematic roles such as Agent had been primitives of Donald Davidson’s event-logic (Davidson 1967a), but he was in error: Davidson did not analyze events in termsof Agent and Patient but in fact rejected H ector Caten~eda’s suggestion (Casten~eda 1967) that the Davidsonian event analysis be modified to do so (in Davidson 1967b:125)2. Though many linguists seem to assume that linguistic theory should include a finite (and short) language-universal canon of thematic roles (that includes the familiar members such as Agent, Patient, Goal, Source, Theme, Experiencer, Instrumental, etc.), no one that I know of has ever attempted to propose a complete list3. There is disagreement even on the most familiar roles(e.g. whether Theme, usually "something that moves or changes state", can be1The exceptions I know of being Chierchia (1984), Carlson (1984), and Dowty (1989), the last discussed below.2That is, what Davidson did propose was that adjuncts (temporal, locative and adverbial modifiers) were predicates of an existentially-qualified event variable in logical form, but subject and object were not: they are traditional "arguments", related to the event variable by the n-place predicate denoted by the verb.3The most comprehensive list I have seen is also the earliest: Blake (1930), who argued that semantically-defined "case relationships" (clearly a similar notion to today’s thematic role-types) are "numerous but not infinite; they are not indefinite and subjective, depending on the lucubrations of the individual mind, but objective, definite, and determined once for all by general grammatical principles and the laws of thought", offered as a "pioneer study" an organized system of 87 temporal and locative roles and 26 other roles, includ-ing such subsequently ignored roles as additional("he gave him a sum of money besides the cattle"),substitu-tive("he gave me promises instead of money") and similative("he barked like a dog").’assigned by’ a stative predicate; and whether Theme is the same role as Patient or whether they are distinct), and new candidates for Thematic Roles are being proposed all the time (e.g.Figure and Ground in Talmy (1985a),Neutral in Rozwadowska 1988),Landmark in Jackendoff (1982), even Subject in Baker 1985).A paper such as this cannot begin to do justice to all the diverse literature on the subject, and a warning to this effect to the reader, plus apologies to the authorswho are omitted or overlooked, are hereby issued.4Among the various understandings of thematic roles, we can distinguish two kinds.What I will call the argument-indexing view of thematic roles is demanded by theÚ-Criterion of GB: each NP argument of a predicate is assigned exactly one Ú-Role,and the same Ú-Role is not assigned to two NP arguments of the same predicate (Chomsky 1981:36, 139). By clear implication, the Ú-Roles that Chomsky originallyhad in mind to fulfill this criterion were the familiar Agent, Patient, etc. from Gruber, Jackendoff, and others. By virtue of the Ú-Criterion, Ú-roles served (originally at least) two main purposes in the GB theory, (i) distinguishing "real", semantically contentful arguments of a predicate from dummy arguments such as itand there, and (ii) helping to keep track of identity and distinctness of NPs as particular semantic arguments of a predicate during the course of a derivation.From the structure of the early Case Grammar theory (Fillmore 1968), it is obviousthat Deep Cases also served an argument-indexing function there, since in Deep Structure each NP argument bears exactly one case label (Agentive, Instrumental, Dative, Locative, etc.), and subsequent syntactic transformations are stated in termsof these labels, not arbitrary or tree-structurally positioned NPs, and this seems to presuppose that there is not more than one Agentive (etc.) NP per clause. (Thiswas modified later: cf. below.)In order for such systems to work, in an account in which the roles Agent, Theme, Goal, etc. are given explicit semantic content, the meanings of all natural language predicates must turn out to be of a very particular sort: forevery verb in the language, what the verb semantically entails about each of its arguments must permit us to assign the argument, clearly and definitely, to some official thematic role or other--it cannot be permitted to hover over two roles,or seem to "fall in the cracks" between roles---and what the meaning entails aboutevery argument must always be distinct enough that two arguments clearly notfall under the same role definition. This is a very strong empirical claim about possible meanings of natural language predicates, and, as soon as we begin to try tobe precise about exactly what Agent, Patient, etc. "mean", all too subject to4In this paper I have tried to follow the practice of citing papers in which, in my view, the essence of a proposal or insight was first made, but not necessarily later discussions of the insight (under the same or different terminology) unless I believe they contributed something new that is relevant here. Hence relatively more references are made to early literature by Fillmore, Jackendoff and their contemporaries, and relatively fewer references to recent literature on roles, than is sometimes found elsewhere.difficulties and apparent counterexamples.Doubts as to whether the familiar short lists of Roles/Deep Cases (or refinements thereof) would ever really work this way already arose in the Case Grammar days (e.g. Cruse 1973, H uddleston 1970, Mellema 1974, Fillmore 1971a, and many others). Later GB writers saw the danger too, and proposed to circumvent the problem by refraining from committing themselves to the traditional roles, whatI will henceforth call thematic role types, and instead invoked individual thematic roles---these terms from (Dowty 1989)5. That is, we simply call the thematic role of the subject of the verb hit the "hitter role", that of the subjectof kill the "killer role", of build the "builder role", and so on, with no assumptionmade that there is one thematic role type common to these arguments (Marantz 1984, van Riemsdijk and Williams 1986)---though the possibility that role typesalso exist need not be ruled out, either. Trivially then, there will be enough distinct Ú-roles around (i.e., the individual roles) to permit the Ú-Criterion to be satisfied, i.e. to preserve the argument-indexing view of thematic roles.Nevertheless, many syntacticians working within the GB framework have continued to appeal to the traditional thematic role types to state syntactic generalizations (Rappaport and Levin 1988, Nishigauchi 1984, Belletti and Rizzi 1986, etc.). And appeal to a particular hierarchy of thematic roles, such as Nishigauchi (1984) does in stating control principles (i.e. Source >... ), requiresALL arguments of predicates (at least those that ever occur in control relationships), to have roles mentioned in the hierarchy, i.e. a role-type, not an individual role. Thus for such hypotheses, it IS a crucial question whether there isa small set of distinguishable role-types that effectively index all arguments.In contrast to the argument-indexing view, Jackendoff’s research on thematic rolesis of a fundamentally different kind. For him, thematic relations (the term he prefers to roles) are most importantly notions of conceptual structure, as elucidatedin Jackendoff (1983, 1987), rather than basically syntactic or interface notions;they are not theoretical primitives but are defined by particular configurations of primitive operators such as GO, STAY and CAUSE in conceptual structure; one discovers their nature and distribution empirically by looking at certain lexicaland syntactic patterns in natural language in relation to their meanings, e.g. the distribution of prepositions in particular (though not, perhaps surprisingly, by psychological experiment). And the thematic roles one finds by this method do notby any means turn out to obey the theta-criterion: some verbs turn out to assignmore than one role to the same argument, others assign the same role to two different arguments, and some verbs "have" thematic roles that they do not assignto any NP, e.g.to butter has both a Theme and a Goal role, but the Theme is5For convenience, I will continue to use Thematic Role for role types, when no confusion between role types and individual roles can arise."completely expressed by the verb" (1987:387). Whether all arguments of all verbs receive one of the thematic relations he has mentioned may not be stated, but his view of roles would not seem to require that they all do. In short, Jackendoff’s interest in thematic roles arises purely from his desire to describe semantic patterns in lexical subcategorization and in syntax (that to him reveal conceptual structure), not to index arguments, and that thematic biuniqueness does not seem to result is of no concern. The individual-thematic-role escape hatch is of no interest to the Jackendoffs and Fillmores (or to this writer), for it ignores precisely the semantic generalization of role-type across verbs that gives the notion its interest. It should be added that Fillmore’s later work on Case Grammar also permitted more than one case per argument (Fillmore 1977) (and of course he had never advocated a one-to-one relation between Deep (semantic structure) Cases and surface constituents).Alas, this paper is not going to solve all these problems and does not purport to offer a theory of thematic roles that serves everyone’s needs perfectly---nor does it attempt to demolish the notion once and for all. Its goal are more modest: (1) to lay out some methodological groundwork for studying thematic roles with the tools of model-theoretic semantics, and to propose some new strategies for attacking the area one step at a time, (2) to propose one new account of thematic roles (not unrelated to some other recent proposals) that seems to have merit at the "first step" in the strategy, and (3) perhaps most important of all, to make syntacticians and all linguists recognize the dangers of continuing to take this notion for granted and of assuming thematic roles are as well-motivated as phonemes or phrase-markers, and to encourage others, by this one example, to invent and explore other novel theories of thematic roles. And though this is not a psycholinguistics article and I am not a psycholinguist, I believe the linguist making a theoretical proposal about an area such as this has the responsibility to point out what psycholinguistic implications his proposal could have (the extent is it correct) and what questions it raises; thus the paper will include some speculations of this kind.As is customary in model-theoretic semantics, I begin with the question of what logical type thematic roles should have, summarizing briefly the results of Dowty (1989) in §2. As the traditional empirical difficulties with arriving at a well-motivated set of role-types (most of all an argument-indexing set) may not be well-known today, I survey these in §3, including some pitfalls of misidentifying roles. It is argued in §4. that a fundamental methodological problem is that we have no agreement on what kind of linguistic evidence is appropriate for identifying a role-type correctly, and as a remedy, a strategy is defended of examining first the domain of argument-selection alone. As a further constraint on legitimate kinds of roles, I argue in §5 that event-dependent but not perspective-dependent roles be admitted. The inventory of role-types must, in view of the definitions in §4, be widened to involve a new kind ofrole,Incremental Theme(§6.). With this preparation, I introduce a new theory of roles, in while roles are "prototypes", here called thematic proto-roles, rather than discrete categories (§7); the argument-selection principles for this theory and their workings are discussed in §8. Most interesting for this account of roles are three cases of subtly-contrasting argument selection: partially symmetric interactive predicates (§9.1), psychological predicates (§9.2), and the spray-load alternations (§l.3). Comparisons of the present view of roles with related proposals in the literature are made in §10. Some psycholinguistic implications that this account suggests for the place of thematic roles in the acquisition of grammar and of lexical meanings are considered in §11, and finally, what this account might imply about the so-called "unaccusative" phenomenon is considered in §12. The paper concludes with a brief summary of its proposals in §13.2. The Logical Type of Thematic RolesBecause this paper uses model-theoretic semantics as its main investigative tool, we should begin our semantic investigation by asking what logical type thematic roles must be given in a formal semantic theory, in order for our theory to model the properties linguists have traditionally attributed to them. As Dowty (1989) is devoted to that question, I summarize here only very briefly the results of that paper and refer the reader to it for further details.From the semantic point of view, the most general notion of thematic role (type) is a set of entailments of a group of predicates with respect to one of the arguments of each.(Thus a thematic role type is a kind of second-order property, a property of multi-placed predicates indexed by their argument-positions.)For example, consider the subject argument of the two-place predicates x murders y, x nominates y , x interrogates y: entailments they all share include that x does a volitional act, that x moreover intends this to be the kind of act named by the verb, that x causes some event to take place involving y(y dies,y acquires a nomination,y answers questions--or at least hears them), that x moves or changes externally (i.e. not just mentally). The first entailment is not shared by kills (traffic accidents also kill), the second not by convinces(once can convince, or kill, inadvertently but cannot murder inadvertently), the third not by looks at, the last not by understands. By entailment, I mean the standard logical sense: one formula entails another if in every possible situation (in every model) in which the first is true, the second is true also. Since we are discussing entailments of "non-logical" predicates, I take this to be the same as an analytic implications (for which I also use the term lexical entailment: the implication follows from the meaning of the predicate in question alone). That is, a role-type like "Agent" is defined semantically as whatever entailments of verbs about NP referents are shared by the verbal argument-positions we label with the term "Agent" (and excludes whatever is entailed for those arguments that differs from one verb to the next); this sidesteps the question of whether "Agent" has a more "atomic" meaning underlying it, but it iss precisely the point here to have an exact way of semantically characterizing roles that avoids such a presupposition, that can describe a possibly "arbitrary" as well as a "natural" role type, so that we can investigate and compare theories which do and don’t involve the traditional notions.Some of the lexical entailments that will be under discussion are perhaps also correctly described as presuppositions (in which case they correspond to the selectional restrictions of Chomsky (1965), but I assume it is now uncontroversial that these are correctly analyzed as semantic properties, not syntactic properties, of words). But the difference between presupposition and lexical entailments will not be important for our purposes.This definition has the advantage that it is compatible with a theory, like Jackendoff’s (1972, 1987) or Foley and van Valin’s (1984), in which thematic role-types are defined by certain configurations of the (explicitly or implicitly interpreted) logical structures into which natural language predicates are translated1; with a theory, like Zaenen’s (1988) or Rozwadowska’s (1988), in which thematic roles are sets of semantic features (as long as we can fix a definite set of entailments, within some formal semantic framework, to correspond to each such feature of those accounts), as well as a theory in which there is no internal "structure" to lexical meanings and in which entailments of lexical meanings are all listed independently (e.g. by meaning postulates) and do not completely "cross-classify" by semantic primitives in any neat way as structuralist semantic theories assume lexical meaning does. It is also neutral as to whether thematic roles are argument-indexing or not.2Yet the definition allows us to be as precise as possible in describing the substantive semantic content of thematic roles: as precise or more so, I believe, than any kind of current semantic theory does. When "entailments" are mentioned below, the reader should keep in mind that this notion is neutral among these various theoretical views.1See Dowty (1979) for a demonstration of how English predicates can be interpreted (compositionally within asentence) by translating them into a "logical form" or "semantic representation" where they are decomposed intoelements such as CAUSE and BECOME, these translations then being part of a formal model-theoreticinterpretation of English.2Dowty (1989) also points out that if there is a set of effectively argument-indexing thematic role types for allpredicates of a language, then an expressively equivalent language is one in which n-place predicates arerepresented in the "neo-Davidsonian" way with such predicates and their arguments replaced by event-predicateswith thematic roles as relations between events and participants, e.g. in which "Mary kissed John yesterday" isrepresented by (ii) rather than (i):(i) yesterday[kiss(Mary, John)](ii) Ee[kissing(e) & Agent-of(John,e) & Patient-of(Mary,e) & yesterday(e)](but of course this conversion is not possible if thematic roles are not effectively indexing). However, it is not clearwhat kind of conceptual or computational advantage, if any, (ii) achieves, once lexical entailments are also takenaccount of (Dowty 1989). The view of thematic roles as second-order properties of relations indexed by argumentis equally adequate whether thematic roles are indexing are not.3. Traditional Problems in Identifying Thematic Roles and Using Them to Distinguish Arguments3.1 Role Fragmentations and Unclear BoundariesOf various examples that might be cited of the question how "finely" to divide thematic roles, perhaps Agent is most striking: this is one of the most oft-cited and in some sense a very intuitive role, but it is one of the hardest to pin down. Jackendoff (1983) divides it into Agent vs. Actor, but D. A. Cruse (1973) split it four ways,(1) a.Volitive"an act of the will is stated or implied" (p. 18).b.Effective"exerts a force...because of its position, movement, etc." (p.19)c.Initiative"initiation of an action by giving a command" (p. 20)d.Agentive"performed by an object [living things, certain types ofmachine, and natural agents] regarded as using its own energyin carrying out the action." (p. 21)and cites syntactic tests to isolate each new role type. Possibly Lakoff (1977: 244) offered the largest fragmentation of Agency ever proposed, in which there were fourteen supposedly distinct characteristics (though properly speaking, some of Lakoff’s characteristics involved the RELATIONSHIP between agent and patient, not agency by itself). The dilemma is, if we adopt the finer categorization of roles to achieve certain distinctions, do we thereby not miss generalizations by not being able to refer to the grosser Agent category as well?Linguists have often found it hard to agree on and motivate the location of the boundary between role types. The sentences in (2) show one example of the difficulties that can be involved:(2) a. I walked a mileI swam 30 meters,I slept twelve hours.b. This weighs five poundsThe piano measures 6’5".It took me an hour to grade the papers.The book cost me $5.c. I paid $5 (this amount) (?this $5-bill) for the book.The book cost me $5 (?this amount) (#this $5-bill).I bought the book for $5 (this amount) (#this $5-bill)d. I paid for the book with ?$5 (#this amount) (this $5-bill).I bought the book with ?$5 (#this amount) (this $5-bill).e. I’ll trade this record for the book.These sentences may involve a little-studied thematic role that has been be called Extent (Andrews 1985). Note first that in (2a) the phrases a mile, 30 meters, 12 hours are adjuncts rather than subcategorized elements (they may be freely omitted without lose of acceptability or, apparently, change in the meaning of the rest of the sentence) and have an "adverbial function". Can adjuncts, or adverbs themselves, be assigned a thematic roles? Fillmore (1988) said yes, but there would seem to be room for doubt. If we can assign measures of distance or weight a thematic role, how about measures of rate, as in He drove the car 50 m.p.h.?But then where do we stop? E.g. does too fast have a thematic role in He drove the car too fast, or does quickly in She walks quickly?On the other hand, similar NPs are clearly subcategorized argument NPs in (2b), so surely they ARE assigned thematic roles here, and their meaning seems quite parallel to (2a): If we say these NPs have thematic roles in (2b) but not in (2a) (contrary to Fillmore, I presume), then it seems we ignore the semantic parallelism and say that it is a matter of syntactic form, not the meaning of a sentence alone, that determines what thematic roles are involved. (Perhaps indeed this is the correct conclusion, but the concept of thematic role becomes quite a different one if the conclusion is accepted rather than rejected, and if we cannot use meaning alone to decide thematic assignment, then we need to justify which syntactic differences we allow to indicate role differences and which we do not.)What do we make of the differences between (2c) and (2d)?five dollars and this amount, like a mile, etc., seem to refer to an measurement of monetary quantity (in the abstract), while this five-dollar bill refers to a concrete object, a piece of paper that has such a value. So perhaps the correct thing to say is that the verb forms in (c) make reference to the measurement (and have the Extent role) while those in (d) refer to a physical quantity of currency (and have some other role, say Theme, parallel to (e)). The break, however, is not quite that clean. One can also say That bad investment cost me my house in the country(where my house...is not merely an Extent NP). And in the temporal domain, we have John spent Tuesday writing the paper as well as John spent an hour washing the car(suggesting Tuesday can express Extent, though cf.#It took John Tuesday to wash the car).But the confusing part is about (c) and (d) is that in the common commercial transaction there exist BOTH a concrete pile of currency that changes hands AND a particular measurement of value that this currency has (except that in purchase by check or credit card, the former may be absent in concrete form, yet presumably there is still a "virtual Theme" of currency). So, we wonder, by analogy to Jackendoff’s。

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a r X i v :h e p -l a t /0605005v 4 21 M a y 2008Study of Possible Proton-Antiproton Hexaquark State in Lattice QCDMushtaq LoanInternational School,Jinan University,Huangpu Road West,Guangzhou 510632,P.R.China(Dated:May 21,2008)We have used standard techniques of lattice quantum chromodynamics to look for evidence of the spin-zero six quark ﬂavour singlet state (J P C =0−+)observed by BES Collaboration,and to determine the splitting between the mass of the possible proton-antiproton and the mass of two protons,its ing the various interpolating ﬁelds we ﬁnd indications that for suﬃciently light quarks proton-antiproton is slightly above the 2m p threshold.The lattice resonance signal of binding observed near the physical and continuum regimes do not support the existence of proton-antiproton state as a spin-zero hexaquark state.PACS numbers:11.15.Ha,12.38.Gc,11.15.MeRecently,the BES Collaboration in Beijing observed a near threshold enhancement in the proton-antiproton (p ¯p )mass spectrum from J/ψ→γp ¯p radiative decay [1].Fitting the enhancement with an S -wave Breit-Wigner resonance function,results in peak mass at M =1859+310(stat)+525(sys)with a total width Γ<30MeV /c 2.With a P -wave ﬁt,the peak mass is very close to the threshold,M =1876.4±0.9MeV and the total width is very narrow,Γ=4.6±1.8MeV.This discovery is subse-quently conﬁrmed by the Belle Collaboration in diﬀerentreactions of the decays B +→K +p ¯p [2]and ¯B 0→D 0p ¯p [3],showing enhancements in the p ¯p invariant mass dis-tribution near 2m p .Such a mass and width does not match that of any known particle [4].Theoretical existence of possible proton-antiproton bound state has long been speculated in quark model and conventional nucleon potentials [5,6,7,8].However,it was only in a very recent study,made by Yan et al us-ing the Skyrme model [9],that predicted mass and the width close with the experiment.Experimentally,the quantum numbers of p ¯p (1857)are not well determined yet.The photon polar angle distribution was found con-sistent with 1+cos 2θγsuggesting the angular momentum is very likely to be J =0.Making full use of general sym-metry requirement and available experimental informa-tion the corresponding spin and parity are J P C =0−+[10].In this letter we report ﬁrst quenched lattice QCD calculation capable of studying the p ¯p (1859).In contrast with conventional baryons and mesons,it is diﬃcult to deal with q m ¯q n (m +n ≥3)states in lattice QCD.For example,a q 3¯q 3state can be decomposed into a couple of colour singlets states even in the absence of unquenched eﬀect.The two-point function,in general,couples not only to the single hadron but also to the two-hadron states.We seek operators that has a little overlap with the hadronic two-body states in order to identify the signal of our hexaquark state in lattice QCD.For this purpose,we ﬁrst consider a non two-body-type ﬁeld for I (J P C )=0(0−+)and construct our interpolating ﬁelds based on the diquark description.In Jaﬀe model [11],each pair of [ud ]form a diquarkwhich transforms like a spin singlet (1s ),colour anti-triplet (¯3c ),and the ﬂavor anti-triplet (¯3f ).Therefore,for a diquark operator,one has [12]Q i,a Γ(x )=1√2andO ¯N (x )=ǫdef [¯q d (x )Cγ5¯q Te (x )]¯qf (x )(5)are the standard interpolating ﬁelds for the nucleon andantinucleon,respectively.A more accurate procedure will be to measure the 2×2correlation matrix and extract theeﬀective mass from the eigenvalues using variational techniques [13].In this study,however,we do not intend to pursue this issue further.To examine the possible proton-antiproton ground state in lattice QCD,we generate quenched conﬁgu-rations on a 203×60lattice with tadpole-improved anisotropic gluon action [14]in the coupling range of 3.0−4.0.Gauge conﬁgurations are generated by a 5-hit pseudo heat bath update supplemented by four over-relaxation steps.These conﬁgurations are then ﬁxed to the Coulomb gauge at every 500sweeps.After discarding the initial sweeps,a total of 500conﬁgurations for each coupling are accumulated for ing the tadpole-improved clover quark action on the anisotropic lattice [15]over the lattice spacing range of 0.26−0.39fm,we compute the light-quark propagators at six values of the hopping parameter κt which cover the quark mass region of m u <m q <2m u .To obtain a better overlap with the ground state we used iterative smearing of gauge links and the applica-tion of fuzzing technique for the fermion ﬁelds [16].The application of fuzzing for two of the six quarks inside the hexaquark state ﬂattens the curvature of the eﬀec-tive mass.The largest plateau in the region with small errors is obtained with fuzzed u -and d -quarks.We used this variant to calculate our correlation functions.From the correlation functions we extract the mass (en-ergy)by standard χ2ﬁtting with multi-hyperbolic cosine ansatzC (t )=n i =1A i cosh(tm i ).The ﬁtting range [t min ,t max ]for the ﬁnal analysis is de-termined by ﬁxing t max and ﬁnding a range of t min where the ground state mass is stable against t min .We choose one “best ﬁt”which is insensitive to the ﬁt range,has high conﬁdence level and reasonable statistical errors.Typical example of the eﬀective mass plot is shown in Fig.1.The eﬀective mass decreases monotonically,which im-plies that excited spectral contributions are greatly re-duced.For the χN ¯N -type ﬁeld,an impressive plateau with reasonable statistical errors is observed in the in-terval 35≤t ≤50,where we expect to achieve single state dominance.For the χdq -type ﬁeld,the signal is noisy at earlier times,and hence we ﬁt in the interval 45≤t ≤55.Statistical errors of masses are estimated by a single elimination jackknife method.We kept sta-tistical errors under control by ensuring that analyzed conﬁguration are uncorrelated,which is made possibleby separating them by as many as 500sweeps.The sta-tistical uncertainties on our hadron masses are typicallyon the few percent level.The masses of the non-strange mesons π,ρas well as the nucleon were computed for scale setting and analyzing the stability of hexa-quark state,respectively.25 30 35 4045 50 55 60tM e f fFIG.1:Eﬀective mass of the J P C =0−+color-singlet state as a function of t .The data corresponds to interpolators χdq (open circles)and χN ¯N (open triangles)at β=3.5and κt =0.2380.The chiral extrapolation to the physical limit is the next important issue.From the view point of chiral per-turbation theory,data points with smallest m 2πshould be used to capture the chiral log behaviour.Leinweber et al [17]demonstrated that the chiral extrapolation method based upon ﬁnite-range regulator leads to extremely ac-curate value for the mass of the physical nucleon with systematic errors of less than one percent.Unfortunately there does not seem to exist such a chiral extrapolation technique for multi-quark hadrons beyond a naive one.Since quenched spectroscopy is quite reliable for mass ratio of stable particles,it is physically even more mo-tivated to extrapolate mass ratio instead of mass.This allows for the cancellation of systematic errors since the hadron states are generated from the same gauge ﬁeld conﬁgurations and hence systematic errors are strongly correlated.Fig.2collects and displays the resulting par-ticle mass ratios extrapolated to the physical quark mass value using linear and quadratic ﬁts in m 2πm h =a +bm 2π,m h =a +bm 2π+cm 4π.For the nucleon we have employed the procedure adoptedin Ref.[17].The diﬀerence between these two extrap-olations gives some information about systematic uncer-tainties in the extrapolated quantities.The data behave almost linearly in m 2πand both the linear and quadratic ﬁts essentially gave the identical results.The mass ra-tios extracted from the ﬁelds χdq and χN ¯N are very close and agree within the errors.It can be seen that mass ratios show a weaker dependence on the quark mass.We3expect the contributions from the uncertainties due to chiral logarithms in the physical limit signiﬁcantly less dominant at our present statistics.M a s s (M a s s r a t i o )M ( )2π2GeVFIG.2:Chiral extrapolation of hadron mass and mass ra-tios extracted with the diquark-type (open triangles)and N ¯N(open circles)interpolating ﬁelds at a s =0.32fm.The solid triangles correspond to the proton interpolating ﬁeld.The question whether the lowest-lying J P C =0−+state extracted is scattering state or a resonance is bet-ter resolved by analyzing the ratio of the mass diﬀerences ∆M (between the candidate low-lying hexa-quark state and the free two-particle state)and the nucleon mass.The ﬁtted data,illustrated in Fig.3,show that both the ﬁeld operators give the consistent estimates of the ratio and the masses derived from both the operators are con-sistently higher than the lowest-mass two-particle state.The ratios are clearly positive and increase in magnitude as we approach the physical regime.At zero quark mass∆M M PM ( )2π2GeVFIG.3:Chiral extrapolation of the mass ratios extracted fromdiquark-type (open circles)and N ¯N(open triangles)ﬁelds at a s =0.29fm.the mass diﬀerence for both the ﬁeld operators is ∼55(2)MeV.The chiral uncertainties in the physical limit are less than 2%.In other words,binding becomes weaker near the physical regime with a general trend of positive binding as the zero quark mass limit is approached.A similar behavior observed for the mass diﬀerences between the hexaquark and the two-particle states at smaller lattice spacing a s =0.26fm is illustrated in Fig.4.The ratio obtained from the χdq operator for the ﬁve smallest quark masses is slightly higher than that ob-tained from the χN ¯N operator.For N ¯N-type ﬁeld the mass diﬀerence is ∼56(1)MeV and ∼59(2)MeV for diquark-type interpolator.The chiral uncertainties are estimated to be less than a percent.The positive mass splitting in both these channels could be interpreted as the evidence of repulsion.Similarly,positive mass dif-M ( )2π2GeV∆M M PFIG.4:Chiral extrapolation of the mass ratios extracted fromdiquark-type (open circles)and N ¯N(open triangles)ﬁelds at a s =0.26fm.ferences that approximately remained constant with m 2πand consistent with those obtained at our regular lat-tices was observed on a larger lattice volume of 6.243fm 3.Again the signature of repulsion at quark masses near the physical regime would imply no evidence of the res-onance in the J P C =0−+channel.This suggests that p ¯p (in the quenched approximation)is more complicated and diﬀerent than two-hadron system otherwise.Finally,we performed a continuum extrapolation for the chirally extrapolated quantities in Fig.5.Expecting that dominant part of scaling violation errors is largely eliminated by tadpole improvement,we adopt an a 2s -lin-ear extrapolation for the continuum limit.We also per-form an a s -linear extrapolation to estimate systematic errors.Performing such extrapolations,we adopt the choice which shows the smoothest scaling behavior for the ﬁnal values,and use others to estimate the system-atic errors.As can be seen from Fig.5,the mass ratio again shows a weak dependence on the lattice spacing and varies only slightly over the ﬁtting range.The four non-zero lattice spacing values of the ratio are within40.01-0.02standard deviations of the extrapolated zero lattice spacing result.This will make for unambiguous and accurate continuum ing the physi-0.020.040.060.080.10.120.140.160.18∆M M P(fm )2a s 2FIG.5:Continuum extrapolation of the mass ratios ex-tracted from diquark-type (solid circles)and N ¯N(solid tri-angles)ﬁelds.cal nucleon mass m p =938MeV,we obtain a continuum mass estimate of 1935(19)(60)and 1940(26)(72)MeV for the ground state hexa quark state from χNN and χdq interpolators,respectively.The results from two extrap-olations seem to be in good agreement,within errors.Given the fact that the ratio does not show any scaling violations,we could also quote the value of this quantity on our ﬁnest lattice,which has the smallest error.Never-theless,order 4%errors on the ﬁnally quoted values are mostly due to the chiral and the continuum extrapola-tions.Since the mass diﬀerence between the reported experi-mental p ¯p mass and the physical 2m p continuum is ∼30MeV,naively one may be tempted to interpret the results in Figs.3and 4as a signature of the proton-antiproton bound state on the lattice.But the positive mass dif-ference observed in the range of pion mass diﬀers from what is seen for the p ¯p state studied on the lattice.The continuum results imply that the mass diﬀerence does not move into the continuum with an attractive interac-tion between p and ¯p .This suggests that the observed signal is too heavy to be identiﬁed with the empirical p ¯p (1859)and unlikely to be a signature of a possible proton-antiproton system as a six quark state.However the interaction between a baryon and an antibaryon can be as strong as that of baryon-baryon systems.Therefore we do not discard the interesting possibility that it could be a mixed molecular state of baryon and antibaryon bound by some long-range force of strong or electromag-netic nature or both.We have presented the results of the ﬁrst lattice inves-tigation on the p ¯p state employing improved gauge andfermion anisotropic actions,relatively light quark masses as well as smearing techniques to enhance the overlap with the ground state of the particle.Our analysis takes into account all possible uncertainties,such as statistical,ﬁnite-size,and quenching errors when performing the chi-ral and continuum extrapolations.On the basis of our lattice calculation we speculate that the state is not to be identiﬁed as a bound state of six quarks.However a thorough examination of this question would require the implementation of ﬂavor SU(3)violation.The I =0,p ¯p state couples to 4πη[10]through the s ¯s component of the ηin the quenched approximation.By giving the strange quark a larger mass would alter threshold which in turn would aﬀect the manifestation of the bound state.Unquenched lattice calculations with varying quark mass are needed to conﬁrm our results.I would like to thank R.Jaﬀe,C.Michael,C.De-tar,S.Sasaki,C.Hamer and D.Leinweber for valu-able suggestions.It is a pleasure to acknowledge Shan Jin for his hospitality at CCAST and stimulating dis-cussions.We are grateful for the access to the com-puting facility at the Shenzhen University on 128nodes of Deepsuper-21C.The computations were done using a modiﬁed version of the publicly available MILC code (see /sg/milc.html).This work was supported by the Guangdong Provincial Ministry of Ed-ucation.[1]J.Z.Bai et al .,Phys.Rev.Lett.91022001(2003)[2]K.Abe et al .,Phys.Rev.Lett.88181803(2002)[3]K.Abe et al .,Phys.Rev.Lett.89151802(2002)[4]Particle Data Group,Phys.Rev.D 66,010001(2002)[5]E.Klempt,F.Bradamante,A.Martin and J.-M.Richard,Phys.Rep.368,119(2002)[6]J.-M.Richard,Nucl.Phys.B (Proc.Suppl.)86,361(2000)[7]A.Datta and O’Donnell,Phys.Lett.B 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