2011_autumn-general_biology-09
DEVELOPMENT AND PRELIMINARY VALIDATION OF A PARAMETRIC PEDIATRIC HEAD FINITE ELEMENT MODEL FOR
Proceedings of the ASME Bioengineering Conference Proceedings of the 2011 ASMESummer 2011 Summer Bioengineering Conference SBC2011 SBC2011 June 22-25, Nemacolin Woodlands Resort, Famington, Pennsylvania, USA USA June 22-25, 2011, Farmington, Pennsylvania,SBC2011-53166 SBC2011-53166DEVELOPMENT AND PRELIMINARY VALIDATION OF A PARAMETRIC PEDIATRIC HEAD FINITE ELEMENT MODEL FOR POPULATION-BASED IMPACT SIMULATIONSJingwen Hu , Zhigang Li , and Jinhuan Zhang1 2 1 1,2 2University of Michigan Transportation Research Institute, Ann Arbor, MI, USA, State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing, ChinaINTRODUCTIONHead injury is the leading cause of pediatric fatality and disability in the United States (1). Although finite element (FE) method has been widely used for investigating head injury under impact, there are only a few 3D pediatric head FE models available in the literature, including a 6-month-old child head model developed by Klinich et al (2), a newborn, a 6-month-old and a 3-year-old child head model developed by Roth et al. (3, 4, 5), and a 1.5-month-old infant head model developed by Coats et al (6). Each of these models only represents a head at a single age with single head geometry. Nowadays, populationbased simulations are getting more and more attention. In populationbased injury simulations, impact responses for not only an individual but also a group of people can be predicted, which takes into account variations among people thus providing more realistic predictions. However, a parametric pediatric head model capable of simulating head responses for different children at different ages is currently not available. Therefore, the objective of this study is to develop a fast and efficient method to build pediatric head FE models with different head geometries and skull thickness distributions. The method was demonstrated by morphing a 6-month-old infant head FE model into three newborn infant head FE models and by validating three morphed head models against limited cadaveric test data.MODEL CONSTRUCTIONMethod Overview As shown in Figure 1, the basic concept to develop a parametric pediatric head FE model is to morph a baseline model into different subject-specific geometries using mesh morphing techniques based on landmarks selected on both baseline model and CT images. Different material properties also need to be assigned based on the age of the child. Because this method may be programmed and run automatically, it is a very efficient tool to generate a group of FE head models for children with different ages and head geometries.Mesh Morphing In this study, a 6-month-old child head FE model originally developed by Klinich et al (2) was remeshed and used as the baseline model. It included skull, suture, brain, dura mater, cerebrospinal fluid (CSF), and scalp. Only hexahedral solid elements and quadrilateral shell elements were used in the baseline model. Radial Basis Function (RBF) was utilized to morph the baseline model into any subjectspecific head geometry based on the corresponding landmarks in both the baseline model and CT images (7). Landmarks were evenly distributed throughout the skull surface and special landmarks were also selected along the suture-skull connections. Skull/suture thickness at each landmark was measured from the CT segmentation data, so that morphed model sustained realistic skull/suture thickness. The morphing process included two steps: geometry morphing and thickness morphing. In geometry morphing, the baseline model was morphed to the target head geometry; while in the thickness morphing, skull/suture thickness distribution was adjusted to match the target thickness measured from CT images. The thickness of scalp was assumed to be constant throughout the head and was calculated by averaging measured data from CT images. The baseline model as well as three subject-specific models (8day-old, 10-day-old, and 27-day-old) morphed by the RBF are shown in Figure 2. The skull shape and suture size varied significantly, even though all three infants were less than 1-month-old. There are 38912 solid elements and 7680 shell elements in each model.Baseline model8-day-old model10-day-old model 27-day-old model Figure 2. Baseline and three subject-specific infant head FE models Material Properties Because the infants selected in this study were all less than 1month-old, only one set of material properties of pediatric head 1 Copyright © 2011 by ASMEFigure 1. Procedure to develop a parametric pediatric head FE modelDownloaded From: / on 06/15/2014 Terms of Use: /termscomponents (see Table 1) was applied in all three models. The material parameters were based on those used in previous pediatric head FE models in the literature with similar age (5, 6). Table 1 Material properties used in the infant head FE modelsComponents Skull Suture Dura CSF Scalp Brain Density (kg/m3) 2150 1130 1140 1040 1200 1040 Young’s Modulus (MPa) Poisson's Ratio500 0.22 8.1 0.49 31.5 0.45 0.012 0.499 16.7 0.42 K=2.11Gpa, Gሺtሻ ൌ G∞ ሺG െ G∞ ሻeିβ୲ G0=5.99Kpa, Gஶ =2.32Kpa, β=0.09248/sMODEL VALIDATIONThe three infant head models developed in this study were validated against infant cadaver test data reported by Prange’s et al (8). During those tests, three newborn infant heads (1-day-old, 3-day-old, and 11-day-old) were subjected to two different loading conditions, compression and drop impact. Compression Test Validation In compression tests, the whole infant head was placed between two parallel rigid plates. One plate is fixed and the other is moved along the anterior-posterior direction of the head at 50mm/s. Forcedeformation time history was recorded. The simulation setup is shown in Figure 3. Three infant head models were simulated under the same compression condition. Good correlations were achieved between the test and simulations as shown in Figure 4.applied to develop pediatric head FE models, in which suture size and skull thickness are crucial. In this study, RBF, traditionally used in image processing, was utilized to morph a six-month-old child head FE model into different head geometries with different skull/suture thickness distributions. Because the landmarks were selected not only throughout the skull, but also along the skull-suture connections, the morphed model sustained accurate suture size with accurate skull/suture thickness distribution. The mesh qualities for all three infant head models were comparable to the baseline model. However, future investigations are needed to further validate the robustness of RBF method for FE mesh morphing. Parametric Pediatric Head FE Model The purpose of a parametric pediatric head FE model is to account for the variations of age, head size and shape, suture size, and skull/suture thickness on the head impact responses among the population. The method developed in this study make it possible to automatically generate a group of pediatric head models for performing population-based impact simulations, which is a significant improvement from previous individual-based pediatric head impact simulations. The proposed method can be widely used for future investigations on pediatric head impact response, injury mechanism, and injury tolerance. Limitations and Future Work This study is limited by the fact that only 3 less than 1-month-old infant head models were constructed, same set of material properties was used for all three models, and model validation was performed against limited cadaveric test results. Nevertheless, this study demonstrated the feasibility of using a parametric pediatric head FE model to conduct population-based simulations. In order to improve this model, future work should include statistical head geometry data for children based on age, the relationship between age and material properties for different head components, and more pediatric head cadaver tests for model validation.ACKNOWLEDGMENTSThe authors would like to thank Dr. Matthew Reed and Dr. Jonathan Rupp in University of Michigan Transportation Research Institute for their help on method development and CT data acquisition.Figure 3. Compression test setup Figure 4. Test-simulation comparisonREFERENCES1. Kraus, J.F., Rock, A., and Hemyari, P.,1990, “Brain injuries among infants, children, adolescents, and young adults”. American Journal of Diseases in Children, 144, pp.684-691. 2. Klinich, K.D., Hulbert, G.M., Schneider, L.W., 2002, “Estimating infant head injury criteria and impact response using crash reconstruction and finite element modeling”, Stapp Car Crash J, 46, pp.165-194. 3. Roth, S., Raul, J.S., Ludes, B., Willinger, R., 2007, “Finite element analysis of impact and shaking inflicted to a child”, Int. J. Leg.Med, 121, pp. 223-228. 4. Roth, S., Raul, J.S., Ludes, B., Willinger, R., 2009, “Child head injury criteria investigation through numerical simulation of real world trauma”, Computer methods and programs in biomedicine, 93, pp.32-45. 5. Roth, S., Raul, J.S., Willinger, R., 2010, “Finite element modeling of pediatric head impact: global validation against experimental data”, Computer methods and programs in biomedicine, 99, pp.2533. 6. Coats, B, Margulies, S, S., 2007, “Parametric Study of Head Impact in the Infant”, Stapp Car Crash Journal, 51, pp.1-15. 7. Bennink, H,E, Korbeeck, J,M, Janssen, B, J et al,2007, “Warping a Neuro-Anatomy Atlas on 3D MRI data with Radial Basis Function”, IFMBE proceedings, 15, pp.28-32 8. Prange, M, T., Luck, J, F., Dibb, A et al, 2004, “Mechanical Properties and Anthropometry of the Human Infant Head”, Stapp Car Crash Journal, 48, pp. 279-299. 2 Copyright © 2011 by ASMEDrop Test Validation In drop tests, infant heads were dropped onto an anvil plate under five different directions (vertex, occipital, forehead, left and right parietal) at 15cm and 30cm heights. The acceleration time history was reported. In this study, 15cm and 30cm drop tests were simulated using all three FE models. Because the models were symmetric, test results in left and right parietal directions were combined, and consequently accelerations of four impact directions were compared between the tests and simulations. The means and standard deviations of the peak head accelerations at different impact directions from both tests and simulations are shown in Figure 5. Good matches in both 15cm and 30cm drop conditions were achieved for all four impact directions.a) 15 cm drop height b) 30 cm drop height Figure 5. Model validations under different drop conditionsDISSCUSSIONMesh Morphing Using mesh morphing method to fast develop subject-specific FE models has been reported before in the literature, but has never beenDownloaded From: / on 06/15/2014 Terms of Use: /terms。
2011年国际生物奥赛试题
22nd INTERNATIONAL BIOLOGY OLYMPIADJuly 10-17, 2011Taipei, TaiwanI. Cell Biology 细胞学A1.内啡肽(endorphin) 是由脑下腺与部分脑细胞所分的天然止痛药。
当他与大脑中的内啡肽受体结合后，内啡肽会产生止痛效果与幸福感。
吗啡(morphine) 也能与内啡肽受体结合，并产生类似的止痛效果。
有关内啡肽与吗啡均可与内啡肽受体结合的说明，何者正确？(A)两者分子大小相似(B)两者分子量相似(C)两者为同分异构物(D)两者具相似外型(E)两者静电荷相同A2. 许多生物的大分子都是由小分子的单体聚合而成。
昆虫的外骨骼也是由多糖类聚合而成。
有关此种多糖类的叙述，下列何者错误？(A)完全由葡萄糖聚合而成(B)含有C, H, O 与N 原子(C)结构类似于纤维素(D)工业上可以用来制造葡萄糖胺(E)真菌的细胞壁上也可以发现A3. 细胞中isoleucine的生物合成来自一连串催化threonine的反应。
其间经过a, b, c, d, e五种酶，并产生A, B, C, D 四种中间产物与isoleucine的最终产物。
当isoleucine生产过剩与过量提供threonine时，会出现下列何种现象？(A) isoleucine与threonine会联手抑制酶a的活性(B) isoleucine会与中间产物D 会联手抑制酶e的活性(C) isoleucine 会与酶a结合并抑制它的活性(D) isoleucine 会与酶e 结合并抑制它的活性(E) threonine 会持续经由5 种酶持续产生isoleucineA4. 许多原核生物会利用SO42-作为细胞呼吸作用电子传递链中最终的电子受体。
有关原核生物细胞呼吸作用的叙述，下列何者错误？(A)为无氧呼吸(B) SO42-接受电子后，会伴随水的生成(C)电子传递链会产生质子驱动力(D).产生ATP (E) H+的移动与ATP产生有关A5.细菌生长可以分成三个时期，I. 延滞期，II. 指数期，III. 静止期。
纳米材料用语生物荧光探针
REVIEWNanomaterials in fluorescence-based biosensingWenwan ZhongReceived:18November2008/Revised:29December2008/Accepted:21January2009/Published online:17February2009 #The Author(s)2009.This article is published with open access at Abstract Fluorescence-based detection is the most commonmethod utilized in biosensing because of its high sensitivity,simplicity,and diversity.In the era of nanotechnology,nanomaterials are starting to replace traditional organic dyesas detection labels because they offer superior opticalproperties,such as brighter fluorescence,wider selections ofexcitation and emission wavelengths,higher photostability,etc.Their size-or shape-controllable optical characteristicsalso facilitate the selection of diverse probes for higher assaythroughput.Furthermore,the nanostructure can provide asolid support for sensing assays with multiple probe moleculesattached to each nanostructure,simplifying assay design andincreasing the labeling ratio for higher sensitivity.The currentreview summarizes the applications of nanomaterials—including quantum dots,metal nanoparticles,and silicananoparticles—in biosensing using detection techniques suchas fluorescence,fluorescence resonance energy transfer (FRET),fluorescence lifetime measurement,and multiphoton microscopy.The advantages nanomaterials bring to the field of biosensing are discussed.The review also points out the importance of analytical separations in the preparation of nanomaterials with fine optical and physical properties for biosensing.In conclusion,nanotechnology provides a great opportunity to analytical chemists to develop better sensing strategies,but also relies on modern analytical techniques to pave its way to practical applications.Keywords Nanomaterials.Quantum dots.Gold nanoparticle.Silica nanoparticle.Fluorescence.FRET. Biosensing OverviewSensitive detection of target analytes present at trace levels in biological samples often requires the labeling of reporter molecules with fluorescent dyes,because fluorescence detection is by far the dominant detection method in the field of sensing technology,due to its simplicity,the convenience of transducing the optical signal,the avail-ability of organic dyes with diverse spectral properties,and the rapid advances made in optical imaging.However,it can be difficult to obtain a low detection limit in fluo-rescence detection due to the limited extinction coefficients or quantum yields of organic dyes and the low dye-to-reporter molecule labeling ratio.The recent explosion of nanotechnology,leading to the development of materials with submicron-sized dimensions and unique optical properties,has opened up new horizons for fluorescence detection.Nanomaterials can be made from both inorganic and organic materials and are less than100nm in lengthAnal Bioanal Chem(2009)394:47–59 DOI10.1007/s00216-009-2643-xW.Zhong(*)Department of Chemistry,University of California, Riverside,CA92521,USAe-mail:wenwan.zhong@Wenwan Zhonghas been Assistant Professor ofChemistry at the University ofCalifornia,Riverside,since July2006.She received the Pilot In-terdisciplinary Research Awardfrom the Institute for IntegrativeGenome Biology of UC,River-side.Her current research in-terests are:developing novelanalytical strategies for utilizingnanomaterials in biosensing;studying nanotoxicity using mi-croscale separation techniques like capillary electrophoresis;and developing field-flow fractionation-based methods for purification and analysis of large protein complexes.along at least one dimension.This small size scale leads to large surface areas and unique size-related optical proper-ties.For example,the quantum confinement effects that occur in nanometer-sized semiconductors widen their band gap and generate well-defined energy levels at the band edges,causing a blueshift in the threshold absorption wavelength with decreasing particle size and inducing luminescence that is strictly correlated to particle size. Therefore,the position of the absorption as well as the luminescence peaks can be fine-tuned by controlling the particle size and the size distribution during synthesis, generating a large group of“fluorophores”with diverse optical properties.Another example is the collective oscillation of free electrons on the surfaces of noble metal particles when their sizes drop below the electron mean free path,which gives rise to intense absorption in the visible to near-UV region as well as a significant enhancement of the luminescence of the fluorophore nearby.On the other hand, they can be conjugated to the reporter molecules as optical tags,like organic dyes,due to their ultrafine physical sizes. Hence,this review focuses on the applications of nano-materials,including semiconductor nanocrystals,noble metal nanoparticles,silica nanoparticles,and carbon nano-tubes,in the field of fluorescence-based sensing. Fluorescent nanoparticleQuantum dotsSince their discovery,quantum dots(QDs)have become more and more important as fluorescence labels in biosensing and imaging[1–5].They are semiconductor nanocrystals composed of atoms of elements from groups II to VI(e.g.,Cd,Zn,Se,Te)or III–V(e.g.,In,P,As)in the periodic table[3,5].The quantum confinement effect arising from their very small(<10nm)dimensions results in wide UV-visible absorption spectra,narrow emission bands,and optical properties that can be tuned by size, composition,and shape[1,5].These features come with high flexibility in the selection of excitation wavelength as well as minimal overlap in the emission spectra from multiple QDs,making them excellent labels for high-throughput screening.Additionally,choosing excitation wavelengths far from the emission wavelengths can eliminate background pared to organic dyes,QDs have similar quantum yields but extinction coefficients that are10–50times larger,and much-reduced photobleaching rates[2].The overall effect is that QDs have10∼20times brighter fluorescence and∼100–200 times better photostability[2].Because QDs are intrinsically fluorescent,they can be employed as the reporter molecules for biomolecule detection.For example,QD-based western blot detection kits are able to detect as low as20pg protein per lane[6, 7].In comparison with colorimetric or chemiluminescent detection,which lead to detection limits of around hundreds of picograms of protein per lane,the QD-based protocol was found to require the same measuring time,be more sensitive,sustain a longer storage time after staining with minimal loss of signal,and deliver better image quality [11].Innovative sensing formats have also been developed to utilize the special properties of QDs.A strategy for the smart targeting of protein was reported by Genin et al., which involved linking QDs to an organic dye of CrAsH [8].Since the interaction between CrAsH and cysteine causes a significant increase in CrAsH’s fluorescence, nanohybrids of CrAsH-QD could serve as a probe to locate Cys-tagged proteins and subsequently trace them for more than150s,taking advantage of the high resistance of QDs to photobleaching[8].On the other hand,Soman et al. profited from the much larger size of QDs than organic dyes when designing a protein detection scheme that offers subpicomolar sensitivity[9].In this scheme,QD-Ab conjugates rapidly aggregate in the presence of antigens, resulting in colloidal structures that are1–2orders of magnitude larger in size than the constituents[9].These structures are detected by light scattering in a flow cytometer[9].The detection of various antigens using QDs with different emission properties is possible with this straightforward agglomeration-based detection strategy. Due to their bright intensity and high photostability,they also have a wide range of applications in bioimaging.For instance,QDs can be employed in fluorescence in situ hybridization(FISH)and offer higher detection sensitivity than organic dyes.QD FISH detected the expression of mRNA in neurons within the midbrain region of mouse at ×4magnification,which could only be done at×20 magnification when Alexa Fluor488was used[10]. Streptavidin-coated quantum dots bound to biotinylated peptides were produced in vivo after infection of the target bacterium by an engineered host-specific bacteriophage [11].The system detected the specific bacterium at a concentration of ten bacterial cells per milliliter using flow cytometry or fluorescence microscopy[11].The optical properties of QDs—a wide absorption spectrum,narrow emission peak,and high photostability—provide great advantages in high-throughput analysis[12–15].Multi-plexed detection of Bacillus anthracis was performed on a fiber-optic microarray platform using five types of QDs and the organic dyes Cy3and Cy5.This eight-reporter system provides a fourfold throughput enhancement over standard two-color assays[14].Even though QDs are a very promising replacement for traditional organic dyes in labeling biomolecules for bioassays and bioimaging,their surface properties need to48W.Zhongbe improved for better aqueous solubility and functionality, their stability should be enhanced,and their nonspecific binding to biomolecules needs to be decreased.Various methods have been developed for these purposes.Ligand exchange is a method commonly used to replace the hydrophobic capping molecules with bifunctional linker molecules for both enhanced solubility in water and to generate functional groups for chemical conjugation with biomolecules on the surface[2,5].Another approach is to cover the hydrophobic surface groups through interactions with amphiphilic molecules like octylamine-modified poly-acrylic acid[2,5].This approach does not alter the surface and optical properties of QDs,because the original hydrophobic layer outside the core/shell CdSe/ZnS is intact. Polyethylene glycol(PEG)is another useful molecule for surface modification of QDs,because it is not only a good adapter for a variety of functional end-groups,such as biotin,amino,and carboxyl groups,but it can also help to improve the stability of QDs and decrease nonspecific binding[16].It has been proven that QDs encapsulated in oligomerized PEG-phospholipid micelles are stable for weeks in pure water(no change in precipitation and fluorescence was observed),and over90%of the fluores-cence was retained after5,000min when the oligomeric PEG-phospholipid micelle QDs were dispersed in acetate, phosphate,and borate buffers with low salt contents.In contrast,the fluorescence of monomeric PEG-phospholipid micelle QDs dropped drastically to<50%or even30% under the same conditions[17].Surface oxidation and pH value during storage are two prominent factors that influence QD stability.For extended stability in basic buffers,dihydrolipoic acid(DHLA)could be attached to the QD surface via a PEG linkage[18].The hydroxyl-coated QDs prepared by Kairdolf et al.showed stability under both basic and acidic conditions,with minimized nonspecific binding[19].All of these surface modification routes strengthen the compatibility of QDs with bioassays and should be continued in order to further enhance their applicability in the field of biological science.Toxicity is another issue that needs to be solved before QDs can be widely applied in biomedical studies performed in vivo,although it may not be a big problem in biosensing performed in vitro.Fluorescent silica nanoparticlesAnother type of fluorescent nanomaterial which has been extensively tested as a labeling reagent in the detection of pathogens,nucleic acids,and proteins is silica nanoparticles doped with organic dyes[20–25].This type of nanomaterial has the following advantages in biosensing:(1)silicon is abundant and nontoxic;(2)the high surface-to-volume ratio of the nanoparticles facilitates their binding to biomole-cules;(3)the inclusion of a large number of fluorescent dye molecules inside each nanoparticle results in excellent photostability due to the ability of the silica matrix to shield from molecular oxygen,and the inclusion also dramatically increases the dye-to-biomolecule labeling ratio,leading to high signal amplification factors during detection;and(4)silica is relatively inert in chemical reactions,but still allows surface modification with well-established chemistries[20,21].Compared to QDs, fluorescent silica nanoparticles have a wider size range, spanning from a few to hundreds of nanometers;they require less strict size control,and exhibit better water solubility[20,21].However,problems related to particle aggregation and nonspecific binding on the silica surface have been observed and will need to be solved before the full potential of silica nanoparticles in biosensing can be realized[20].Studies have shown that a ratio of inert to active functional groups on the surfaces of silica nano-particles that results in a high zeta potential is critical to maintaining a well-dispersed nanoparticle suspension and reducing nonspecific binding[26].Other than organic fluorophores,silica particles can also encapsulate quantum dots.The encapsulation not only retains the unique optical properties of QDs,but it also eliminates the aqueous solubility and modification problems associated with QDs and reduces the toxicity of QDs by preventing the leakage of heavy metal ions into the environment[27].Furthermore,magnetic nanoparticles can be co-embedded with QDs to allow handy manipu-lation of the particles using a magnetic field.Such multi-functional particles could be employed in live cell imaging [27–30].Since toxicity is always a big concern when using cadmium-containing QDs in biomedical research,efforts have been expended to generate silicon QDs(SiQDs)that are far less toxic than group II–VI QDs.However,the indirect bandgap character of silicon results in the extreme-ly low light emission efficiency.Recently,silicon quantum dots with photoluminescence quantum yields of over60% have been demonstrated for organically capped silicon nanocrystals,with emission in the near-infrared range[31, 32].Other big challenges in making biocompatible SiQDs include the instability of their photoluminescence due to their fast oxidation rate in aqueous environments,and the difficulties involved in attaching hydrophilic molecules to the SiQD surface[33–36].Optimal surface functionaliza-tion,such as capping the surface of the SiQD with NH2, SH,OH,acrylic acid,and alkyl groups,has been sought to produce water-dispersible SiQDs while maintaining spec-tral and colloidal stability[33–36].Highly stable aqueous suspensions of SiQDs encapsulated in phospholipid micelles were prepared and applied as luminescent labels for pancreatic cancer cells[35].However,applications ofNanomaterials in fluorescence-based biosensing49SiQDs in biosensing and biomedical imaging are still in their infancy because the mechanism responsible for the visible photoluminescence(PL)of SiQDs and the relation-ship of PL to surface functionalization are not yet clear [34].Moreover,a comprehensive comparison of the optical properties of organic dyes or Cd-based QDs with SiQDs has not been made,which makes it impossible to assess the analytical performance of SiQDs in biosensing.Metallic nanomaterials for fluorescence enhancement It has been known for a long time that metallic nano-structures can enhance the fluorescence of nearby fluo-rophores[37–39].Interactions between the dipole moments of the fluorophores and the surface plasmon field of the metal can increase the incident light field,which results in enhanced local fluorescence intensity and rate of excitation. Such interactions also boost the radiative decay rates, leading to an improved quantum yield and a reduced lifetime of the fluorophore[37–39].It has been estimated that the local electric field and the radiative rate could be increased by factors of140and1,000,respectively,near a silver particle[38].In addition,the shorter lifetime comes with the advantage of higher photon flux and increased photostability[37,38].The combined effect is the amplification of the total number of detected photons per fluorophore by a factor of105,significantly enhancing the detectability of the fluorophore[38].Surfaces on which silver islands or silver particles have been deposited are common platforms in bioassays utilizing MEF as the reporting system.Enhancements of the detection signal ranging from ten-to fortyfold have been observed on silver island film(SiF)-coated glass surfaces in comparison with the bare glass[40,41].An approximately thirtyfold increase in the fluorescent intensity of indocya-nine green was observed on a silver colloid-coated planar surface[42].The distance from the fluorophore to the metal surface is a critical factor in successful fluorescence amplification,because a distance that is too short can lead to quenching of the dye[43].Such a distance dependence of the transfer of electronic energy from a donor plane of molecules to an acceptor plane was modeled by Aroca et al. in the early1990s[44].The ideal range is50–200Åfrom the metal surfaces,which makes conjugation of dye-labeled molecules on the silver surface necessary for MEF[38,43]. The thickness of the silver coating also plays an important role in MEF.A study conducted by Zhang et al.found that the fluorophore was quenched on a silver film of2nm, enhanced on a film thicker than5nm,and reached saturation at20nm[45].Anisotropic silver nanostructures have been constructed for MEF as well because theoretical calculations indicated that the surface of a spheroid with an aspect ratio of1.75could lead to a greater reduction in the radiative decay rate than that of a sphere or a more elongated spheroid[43,46].A fiftyfold fluorescence enhancement was observed with high loading of nanorods on the surface,and triangular silver plates led to an enhancement factor of16[46].Metals other than silver have been tested for their effects on MEF.For instance,the use of a gold nanostructure coupled to CdSe/ZnS nanocrystals for MEF was demon-strated with precise control and high spatial selectivity over the fluorescence enhancement process[47].While silver or gold nanostructures achieve MEF in the visible to near-infrared region,aluminum nanoparticles deposited on SiO2 substrate could work in the ultraviolet–blue spectral region, which broadens the application range of MEF[48].Copper particulate films were also found to generate a moderate enhancement effect[49].MEF has been employed to increase the sensitivity in the detection of DNA,RNA,and proteins in the microarray format[50–52].A twenty-eight-fold fluorescence enhance-ment was observed for the near-infrared/infrared dye Cy5, but only a fourfold enhancement was obtained with Cy3, probably due to the stronger scattering component of the extinction spectrum of Cy5(Fig.1)[52].Sensitive detection of a484-mer RNA with a detection limit of25 fmol(4ng)has been demonstrated with MEF and a detection probe consisting of a TAMRA-labeled DNA oligo [53].Detections of a few nanograms of RNA in RNA capture assays had only been achieved previously with enzymatic signal amplification via alkaline phosphatase or linear mRNA amplification during cDNA synthesis,which are more complicated and time-consuming processes than the MEF-based method[54,55].Proof-of-principle detec-tion of proteins has been demonstrated using model systems like avidin–biotin and antigen(myoglobin)–antibody[51]. Moreover,silver island film and MEF have the potential to increase the sensitivities of bioassays performed on cell membranes.Cells were simply cast onto glass slides covered with silver islands and dried before measurement [56].Because the fluorescence signals of the fluorophores bound on the cell membranes were enhanced dramatically by the SiF supports while the intensity level of the intracellular fluorophores was not changed,the MEF helped to distinguish membrane-bound signals from those inside the cells[56].In order to spatially and kinetically accelerate the binding of biomolecules onto the surface,microwave heating was employed to enable ultrafast detection by MEF [57,58].The microwave-based approach also facilitated the release of genomic materials from bacteria spores.Extrac-tion and detection of DNA materials from less than1000 Bacillus anthracis spores have been achieved within one minute by the microwave-assisted MEF technique[59]. Without MEF,Taqman®real-time PCR was needed to50W.Zhongdetect the same DNA materials from 100unprocessed bacterial spores within 2h [60].The use of biomolecule-conjugated silver nanoparticles allows MEF to be applied to solution-based assays as well [61].Solution-based sensing offers faster reaction kinetics and requires simpler experimental apparatus.Silica-coated silver spheres conjugated with Cy3through streptavidin –biotin binding resulted in three-to five-fold fluorescence enhancements [61].Fluorescent core –shell Ag@SiO 2nano-balls were also synthesized by the same group.The silver nanoball was coated with the fluorophore-doped silica shell,and a twentyfold increase in fluorescence was observed with this structure compared to nanobubbles without a silver core (Fig.2)[62].Fluorescence resonance energy transfer (FRET)For assays studying biomolecule interactions and confor-mational changes,FRET is a better technique than simple fluorescence because it is very sensitive to nanoscale changes in distance between molecules [63].Traditional FRET pairs are organic dyes,and modern nanotechnology produces materials like single metal nanoparticles and ionic nanocrystals that can be used as FRET donors or acceptors,offering better FRET effects and more flexible sensing platforms in bioanalysis [63].Metal nanoparticles (NP)Gold nanoparticles are excellent FRET-based quenchers because their plasmon resonance in the visible range makes them strong absorbers and scatterers,with large extinction coefficients of around 105cm −1M −1.Additional superior optical properties include stable signal intensities and photobleaching resistance [63].Gold NP is exceptionally attractive in bioassays due to the ability to finely control particle sizes,and the extreme ease with which biomole-cules containing exposed thiol groups can be attached to the gold surface through gold –sulfur bonds.The gold-sulfur bond also facilitates the attachment of other functional groups such as carboxyl and amine groups via sulfur-containing ligands with special terminal groups.The most typical application of gold NP in FRET-based assays is the labeling of molecular beacons [63].The ends of the hairpin structure are conjugated to Au NP and organic fluorophore,respectively.When the molecular beacon opens up its stem upon binding to its complementary strand in the loop,the fluorophore is released from the Au NP and increased fluorescence intensity is observed.A hundredfoldincreaseFig.1Comparison of the fluorescence on glass and on SiF.A Cy5fluorescence on glass (filled circles )and SIF (empty circles ).B Cy3fluorescence on glass (filled circles )and SIF (empty circles ).C Plots of the intensity enhancement factor versus spotting concentration.Cy5is shown in red ,and Cy3is shown in green .D A Cy5scan for cohybridization with complementary Cy5-and Cy3-labeled targets on glass and SIF substrates.The intensity bar shown lower right is a linear scale from 0counts (black )to 34,000counts (white )[52]Nanomaterials in fluorescence-based biosensing 51in sensitivity was obtained with Au NP compared with traditional dye combinations [64,65].Bridge molecules can also be employed to bring the fluorophores into the proximity of Au NP .For example,β-cyclodextrin (CD)attached to the Au NP surface formed inclusion complexes with the fluorescein molecules which was then quenched [66].This can be utilized to detect cholesterol,because the replacement of fluorescein at the binding site by cholesterol frees the fluorescein from the NP.The fluorescence intensity of the system increased in proportion to the cholesterol concentra-tion [66].The small particle size of Au NP makes them excellent in vivo imaging reagents as well.Au NP modified with FAM-labeled single-stranded DNA was used to image intracellular hydroxyl radicals;here,the DNA strand was cleaved by HO·and released the quenched fluorophore [67].Silver nanoparticles can be excellent acceptors in FRET too,or they can act as enhancers for FRET pairs.It has been found that hybridization of the donor-labeled oligo-nucleotide with the acceptor-labeled complimentary strand on a silver particle surface led to enhanced FRET efficiency with increased Förster distance (from 8.3to 13nm)and a 21-fold faster FRET rate constant [68].Furthermore,the efficiency of FRET between Cy5and Cy5.5on the surfaces of silver particles was increased when the particle size was increased from 15nm to 80nm and when the distance of the donor –acceptor pair from the particle surface was increased from 2nm to 10nm [69].Therefore,as in the case of MEF,silver particles or a silver-decorated surface can act as the supporting material for FRET-based sensing to enhance assay performance.Quantum dotsOther than being directly used as fluorescent labels,QDs have also been widely recognized recently as energy donors in FRET for bioanalysis.Their broad absorption and narrow emission spectra allow single-wavelength excitation of multiple donors and can avoid crosstalk with acceptor fluorophores.In addition,the spectral overlap between donors and acceptors can be adjusted by tuning the particle size.Moreover,QDs are nanostructures that can be coupled to multiple acceptor fluorophores for higher efficiency in energy transfer and can act as the solid support for biomolecules for imaging purposes or to simplify assay st but not least,the energy transfer between QDs and molecular dyes can be approximately described by the Förster mechanism,and so accurate measurements of donor –acceptor distances can be deduced using the same FRET theory as for organic dyes when QDs are the donors and the organic dyes or QDs are the acceptors [70].However,because of the broad absorption spectra and the long excitation lifetime of QDs,they are not suitable being energy acceptors for short-lived molecular fluorophores [71].FRET-based analyses of nucleic acids,proteins,and other biological molecules have been reviewed extensively by Algar et al.Applications of QDs as the donors in FRET for DNA point mutation analysis,detection of pathogenic DNA,construction of molecular beacons with increased photostability,and immunoassays were covered in that review and will not be discussed here [71].Some new applications of QDs as FRET probes included detectionofFig.2Fluorescence emission intensities of Eu-TDPA-doped Ag@SiO 2and Rh800-doped Ag@SiO 2,as well as those of the corresponding fluorescent nanobubbles,Eu-TDPA-doped SiO 2and Rh800-doped SiO 2(top ).The bottom of the figure presents scanning confocal images of (A )Alexa 647Ag@SiO 2,(B )Alexa 647@SiO 2,and (C )zoomed-in version of panel (B ).TDPA ,tris(dibenzoyl-methane)mono(5-aminophenanthroline)europium;Rh ,rhodamine [62]52W.Zhongthe actions of biological enzymes such as protease,polymerase,and nuclease,or even visualization of the pH change in solution,as demonstrated by Suzuki et al.[72].Multiplexed detection of trypsin and deoxyribonuclease was also demonstrated [72].On the other hand,QD-mediated FRET can contribute greatly to the process of drug discovery and development.For example,it can be employed to image the cargo-unpacking process that occurs inside cells during drug delivery.The plasmid DNA is labeled by QDs and the polymeric gene carriers,such as chitosan and polyethyleneimine,are labeled with Cy5[73].The dissociation of plasmid DNA from the polymeric carriers after entering the cells releases the fluorescence of Cy5,as visualized by confocal microscopy [73].In anotherexample,QD-based FRET was employed to quantify RNA –peptide interactions that could be applied in the screening of libraries of small-molecule drugs (Fig.3)[74].The important HIV-1regulatory protein Rev was labeled with Cy5,and the Rev responsive element on HIV RNA (RRE RNA)was bound to the 605QD via the biotin –strapavidin interaction [74].Association of Rev with the RRE RNA permitted the excitation of Cy5at 444nm,a wavelength outside of the excitation range of Cy5,which would then decrease upon the binding of a small-molecule inhibitor like proflavin [74].Using the 605QD as the FRET donor not only eliminated the interference from the intrinsic fluorescence of the inhibitor (proflavin),the emission spectrum of which significantly overlaps with theabsorp-Fig.4Chemical structure of the QD –Con A –β-CD –Au NP nanobiosensor,and schematic illustration of its FRET-based operating principles [76]Fig.3A Conceptual scheme for a single-QD-based nanosen-sor for evaluating Rev peptide –RRE interactions and theinhibitory efficacy of proflavin based on FRET between 605QD and Cy5.B Histograms of the measured FRET efficiency for 605QD/RRE –Rev peptide/Cy5complexes as a function of increasing Rev peptide-to-RRE ratio.The solid curves represent the fit of the experimental data to a Gaussian function.C The variation in the number of Cy5burst counts with increasing Rev peptide-to-RRE ratio [74]Nanomaterials in fluorescence-based biosensing 53。
2009年全国专业技术人员职称英语等级考试卫生类真题及答案合集
云考网 年全国专业技术人员职称英语等级考试卫生类真题及答案合集2009年全国专业技术人员职称英语等级考试综合类A级真题及答案第一部分：词汇选项1. Why can't you stop your (enternal) complaining?A. longB. everlastingC. temporaryD. boring2. Hundreds of buildings were (wrecked) by the earthquake.A. shakenB. damagedC. fallenD. jumped3. These paintings are considered by many to be (authentic).A. faithfulB. royalC. genuineD. sincere4. Many economists have given in to the fatal (lure) of mathematics.A. attractionB. simplicityC. powerD. rigor5. Ten years after the event, her death still remains a (puzzle).A. mistB. togC. mysteryD. secret6. irritated答案：A. annoyed7. duplicated答案：D. copied8. spurred答案：B. encouraged9. ample答案：D. enough10. marvels答案：B. miracles11. perpetual答案：B. endless12. shabbyA. oldB. unforgetableC. funnyD. unfair13. adhere toA. followB. orderC. proveD. handle14. barren答案：C. bare15. specifications答案：C. instructions第二部分：阅读判断Keep on FightingTurning once again to the question of invasion, I would observe that there has never been a period in all these long centuries of which we boast when an absolute guaranteeagainst invasion, still less against serious raids, could have been given to our people. In the days of Napoleon the same wind which would have carried his transports across the Channel might have driven away the blockading fleet. There was always the chance, and it is that chance which has excited and befooled the imaginations of many continental tyrants. Many are the tales that are told. We are assured that novel methods will be adopted, and when we see the originality of malice, the ingenuity of aggression, which our enemy displays, we may certainly prepare ourselves for every kind of novel stratagem and every kind of brutal and treacherous manoeuvre. I think that no idea is so outlandish that it should not be considered and viewed with a searching, but at the same time, I hope, with a steady eye.We must never forget the solid assurances of sea power and those which belong to air power if it can be locally exercised. I have, myself, full confidence that if all do their duty, if nothing is neglected, and if the best arrangements are made, as they are being made, we shall prove ourselves once again able to defend our island home, to ride out the storm of war, and to outlive the menace of tyranny, if necessary for years, if necessary alone. At any rate, that is what we are going to try to do. That is the resolve of His Majesty's government - every man of them. That is the will of parliament and the nation. The British empire and the French republic, linked together in their cause and in their need, will defend to the death their native soil, aiding each other like good comrades to the utmost of their strength. Even though large tracts of Europe and many old and famous states have fallen or may fall into the grip of the Gestapo and all the odious apparatus of Nazi rule, we shall not flag or fail.We shall go on to the end, we shall fight in France, we shall fight on the seas and oceans, we shall fight with growing confidence and growing strength in the air, we shall defend our island, whatever the cost may be, we shall fight on the beaches, we shall fight on the landing grounds, we shall fight in the fields and in the streets, we shall fight in the hills; we shall never surrender, and even if, which I do not for a moment believe, this island or a large part of it were subjugated and starving, then our empire beyond the seas, armed and guarded by the British fleet, would carry on the struggle, until, in God's good time, the new world, with all its power and might, steps forth to the rescue and the liberation of the old.16. Throughout Britain's history, there has been no guarantee that an invasion would not happen.A. RightB. WrongC. Not mentioned17. Napoleon and his army once crossed the English Channel and Conquered Britain.A. RightB. WrongC. Not mentioned18. The enemy will use every means conceivable to destroy Britain.A. RightB. WrongC. Not mentioned19. Churchill is confident that he will live longer than Hitler.A. RightB. WrongC. Not mentioned20. The Royal air Force will launch massive air strikes against the Germans.A. RightB. WrongC. Not mentioned21. The British Empire is so strong that it does not have to take Hitler's menace seriously.A. RightB. WrongC. Not mentioned22. Although many countries have been overrun by the Germans, the British people will never give in.A. RightB. WrongC. Not mentioned第三部分：概括大意与完成句子McGrady's art is a spectacle1. When Tracy McGrady is healthy, his play can be so beautiful that even his own teammates on the court cannot help but admire it - in the middle of a game.2. "It's hard for me, because I'm a fan of basketball," Houston point guard Rafer Alston told the Houston Chronicle newspaper after McGrady's 44-point performance against Utah on January 5. "When he's shooting the ball like that, a lot of times I'm standing there watching and, all of a sudden, [the other team's] getting the ball and going on a fast break, and I'm getting yelled at by the coach." Indeed, McGrady's body control, his energy, his shooting - watching these are like watching an artist at work, blending colours, constructing sentences, or playing music.3. Unfortunately, McGrady, 27, hasn't always been on the job. Already this season, he's missed seven games with back spasms. After Yao Ming was injured on Dec. 23, it appeared Houston would be without both of its stars. McGrady, however, returned three days later and has been playing well ever since, scoring more than 30 points in each of the last six games, as of Tuesday. Houston can't seem to get on without him. When McGrady was injured, the Rockets won two and lost five.4. "Listen, there are only four or five people on the entire planet that can do the things he can do with the basketball," forward Shane Battier said of McGrady. "From a fan's perspective - andwe're fans even though we're players - it's really fun to watch him do that. "From a player's perspective, his game can affect the entire team. No question. We see him, and we get excited, and that pumps us up. He keeps making shots, and suddenly it seems to become easier for everybody."5. But it won't, really. Houston has just begun an important stretch on their schedule. Four of the next seven games will be played away from Houston - and without Yao. Six ofthe games will be against teams with winning records. Opponents will double-team McGrady in an attempt to dull the impact of his art. Instead of watching, McGrady's teammates will need to create a little art of their own.23. Paragraph 2C.24. Paragraph 3D.25. Paragraph 4B.26. Paragraph 5A.A. Necessity for the Teammates to Improve Their Own SkillsB. Evaluation from Two Different PerspectivesC. Spectacular Performance on the CourtD. Players Houston Can't Do WithoutE. Yao Ming's PerformanceF. McGrady's Injury27. McGrady plays basketball so wellA.28. Yao Ming missed several gamesD.29. There are very few people on the EarthC.30. Everyone will have to contributeE.A. that his temmates cannot help admiring himB. that he is often yelled at by the coachC. who can play basketball so wellD. because he had been injuredE. if Houston hopes to winF. since he returned第四部分：阅读理解第一篇Youth Emancipation in SpainThe Spanish Government is so worried about the number of young adults still living with their parents that it has decided to help them leave the nest.Around 55 per cent of people aged 18-34 in Spain still sleep in their parents' homes, says the latest report from the country's state-run Institute of Youth.To coax(劝诱)young people from their homes, the institute started a "Youth Emancipation(解放) programme this month. The programme offers guidance in finding rooms and jobs.Economists blame young people's family dependence on the precarious(不稳定的) labour market and increasing housing prices. Housing prices have risen 17 per cent a year since 2000.Cultural reasons also contribute to the problem, say sociologists. Family ties in south Europe - Italy, Portugal and Greece - are stronger than those in middle and north Europe, said Spanish sociologist Almudena Moreno Minguez in her report "The Late Emancipation of Spanish Youth: Keys for Understanding"."In general, young people in Spain firmly believe in the family as the main body around which their private life is organized," said Minguez.In Spain - especially in the countryside, it is not uncommon to find entire groups of aunts, uncles, cousins, nieces and nephews(外甥/侄子) all living on the same street. They regularly get together for Sunday dinner.Parents' tolerance(宽容) is another factor. Spanish parents accept late-night partying and are wary of setting bedtime rules."A child can arrive home at whatever time he wants. If parents complain he'll put up a big fight and call the father a Fascist," said Jose Antonio Gomez Yanez, a sociologist at Carlos III University in Madrid.Mothers' willingness to do children's household chores worsens the problem. Dioni-sio Masso, a 60-year-old in Madrid, has three children in their 20s. The eldest, 28, has a girlfriend and a job. But life with mum is good."His mum does the wash and cooks for him; in the end, he lives well," Masso said.31. The "Youth Emancipation" programme aims at helping young peopleA. fight for freedomB. live in an independent wayC. fight against social injusticeD. get rid of family responsibilities32. It can be inferred from paragraph 5 that family ties are stronger in Portugal than inA. FinlandB. GreeceC. SpainD. Italy33. Young people's family dependence can be attributed to all the following factors EXCEPTA. parent's toleranceB. housing problemsC. cultural traditionsD. unwillingness to get married34. Which of the following statements is NOT true of Dinoisio Masso?A. She is 60 years old.B. She has a boyfriend.C. She has three children.D. She lives in Madrid.35. The phrase "wary of" in paragraph 8 could be best replaced byA. tired ofB. afraid ofC. cautious aboutD. worried about第二篇Road Trip VacationsIt's summer. In the United States, it's the season of swimming pools, barbeques, camping and road trips.Road trip vacations where the car journey is part of the fun are especially popular with college students, who like to explore the country on wheels. These budget trips are ideal for students who often have plenty of free time but little money."Ever since I went to college, I've been traveling around a lot, exploring the country," said Austin Hawkins, a 19-year-old college student from New York. This summer, Hawkins and his friends have spent weekends traveling in New England.The best part about car trips, said Hawkins, is that you can be spontaneous. "On a road trip, if you get interested in things you see along the way you can stop and explore."Matt Roberts, a 20-year-old student from Ohio who drove to Montreal, Canada, agrees. "With road trips you don't have to plan in advance, you can just get into a car and drive."Even with high gas prices, driving with friends is cheaper than flying. Roberts paid about 40 dollars for gas, but a round trip plane ticket would have cost nearly 400 dollars.Driving trips first became popular in the 1920s. Newly paved roads and improved, cars made it possible to travel longer distances. Motels started appearing outside cities.By the 1950s, car ownership became the norm. Construction of the US interstate highway systembegan in 1956 and motel and restaurant chains popped up everywhere making long distance trips easier.Today, the US has the highest car ownership rate in the world. Only 8 percent of American homes have no car, according to the most recent US census.Though many college students don't own a car, most have access to one. On many of Hawkins' trips, they used a borrowed van.Hawkins' most memorable road trip took place over spring break. He and two friends drove from New York to New Orleans to volunteer, helping rebuild the city after Hurricane Katrina hit it last July. They crossed the country in two days and slept in their car in church parking lots.Roberts' road trip to Canada last winter was even more eventful. Upon arriving in Montreal, they were lost in a blizzard and shivering in the -25°cold. To find their hotel, they turned on a laptop and drove around in circles until they found a spot with wireless Internet coverage."I know we should have planned better, but we're young. Now, when I see those guys I always say: 'Remember when we were lost in the snow storm!' I'll never forget that."36. Traveling on wheels is most popular among peoplewho have cars37. What will Hawkins do when he sees something interesting on a road trip?A. He will turn back.B. He will drive around.C. He will stop to explore.D. He will stop exploring.38. When did motels suddenly appear everywhere?A. After the work to build the interstate highway system started.B. When driving trips became popular.C. After many roads were paved.D. After new cars were made.39. Which of the following words can best describe Hawkins' trip to New Orleans?A. Eventful.B. Colourful.C. Delightful.D. Unforgettable.40. The word "blizzard" in paragraph 12 meansA. snow storm.B. hurricane.C. mist.D. fog.第三篇Tightened Visa RegulationsAccording to South Korea's new visa regulations, native speakers of English who intend to teach English in South Korea will be required to undergo criminal record checks, medical and drug tests, provide sealed academic transcripts and have their university diplomas inspected, The Korea Times has reported. The tightened regulations will affect an estimated 17,000 foreigners that hold E-2 visas specifically for foreign language teachers.The most controversial requirement is that English teachers residing outside South Korea will have to have an interview at a South Korean embassy before taking up their teaching posts. For applicants living in remote areas in Canada, Australia or the US, this is an additional travel burden. Meanwhile, foreign teachers currently living in South Korea must leave the country after theirone-year contracts end and renew their visas at a South Korean embassy in their home country or third country. Before the changes, they could renew their visas by visiting a neighboring country and return without additional documentation.The visa changes are a reaction to public concern about the suitability of some foreign teachers. A report from the South Korean Ministry of Education and Human Resources Development shows between 2001 and August of this year, 1,481 foreign language teachers have been caught for a range of offenses including forged degrees, visa violations and general lawbreaking.But the changes are likely to slow up the supply of teachers to South Korea's English language education sector. According to Michael Duffy, manager of a teacher placement service in South Korea, applicants have to spend a few hundred dollars and several months on getting affidavits fordocuments. "South Korea has put up too many hoops to jump through," he said, adding that foreigners would seek work elsewhere. Most foreigners wonder if the experience of working in South Korea will be worth the burden of the paper work and increasing restrictions. "I don't think (South) Korea has thought this through," said Scott McInnis, a Canadian teacher based in Incheon near Seoul. "This is a reactionary move by the government that will have strong implications for the EFL community."As part of efforts to ease the discontent, the South Korean Ministry of Justice has granted a three-month grace period for current E-2 visa holders to prepare the necessary documents.41. Which of the following is NOT required of an E-2 visa applicant?A. to pass a Korean language testB. to undergo a medical testC. to provide sealed school reportsD. to undergo a drug test41. A to pass a Korean language test42. C visit a neighboring country if they wanted to renew their visas43. C subversive activities44. What does EFL refer to?D English as a foreign language45. The new visa policy aims atB. improving foreign language teaching in South Korea.第五部分：补全短文My Life at RendaI learned very quickly that being a teaching assistant (TA) at the University of Iowa would be different from life as a teacher at Renmin University.________________(46) Eyes staring, mouths open, students examining my big nose, hands nervous, people whispering while I wrote my name on the blackboard.At Iowa, when my first classes began, half my students still hadn't arrived. When everyone finally found a seat, ringing cellphones and loud yawns interrupted my opening remarks.It's not that American students were disrespectful. __________________(47) They were, however, far more skeptical than the students I had at Renda. The truth is I couldn't fault them for their skepticism. Undergraduates at large US universities -especially freshmen and sophomores ? often have several classes a semester handled by TAs. In some cases, the TA sets the course content.______________(48) Most have good intentions, but only a few are as effective asflesh-and-blood professors.Every teacher has to confront obstacles to learning - no matter what the culture. Students who talk during lectures, students who cheat, students who question the grade they get for a paper or project - dealing with these is all part of the job. __________________(49)The difference, I think - at least in my experience is that in the US I had to swallow more of my pride. __________________(50)I had a responsibility to teach them, of course, but I had to do so indirectly-as a guide who himself had a few things to learn from the students.答案：46. Back at Renda, I had walked into my first classes feeling like a celebrity.47. Most were polite or, at least, indifferent.48. In others, the TA works as a grader and discussion leader.49. I encountered these in China, and I faced them in the US.50. In my students' minds, I had little to offer them, except perhaps some sample questions for the mid-term exam.第六部分：完形填空Improve Computer-research SkillsLike many college students, Jose Juarez carries around a pocket-sized computer that lets him watch movies, surf the Interact and text-message his friends.He's part of "Generation M" - those born after 1985 who ________ (51) up connected to everything from video game to cellphones."For us, it's everyday life," said Juarez, 18, a freshman ________ (52) California State University at Sacramento (CSUS). ________ (53),educators are now saying that not all Generation M-ers can synthesize the piles of information they're accessing."They're geeky, but they don't know what to ________ (54) with their geekdom," said BarbaraO'Connor, a Sacramento State communications studies professor who has been involved in a nationwide ________ (55) to improve students' computer-research skills.In a recent nationwide test to ________ (56) their technological "literacy" their ability to use the Interact to complete class assignments - only 49 percent correctly evaluated a set of Web sites for objectivity, authority and timeliness. Only 35 per cent could correctly narrow an overly________ (57) Internet search.About 130 Sacramento State students, including Juarez, participated in the experimental test,________ (58) to 6,300 college students across the country.The hour-long assessment test is conducted by Educational Testing Service. It is a web-based scavenger hunt ________ (59) simulated Interact search engines and academic databases that spit out purposely misleading information."They're very good at ________ (60) in and using the Internet, but don't always understand what they get back," said Linda Goff, head of instructional services for the CSUS library. "You see an open search box, you type in a few words and you ________ (61) the button," said Goff, who is involved in the testing."They take at face value ________ (62) shows up at the top of the list as the best stuff."Educators say that these sloppy research skills are troubling."We look at that as a foundational skill, in the same way we ________ (63) math and English as a foundational skill," said Lorie Roth, assistant vice-chancellor for academic programmes in the CSU systemMeasuring how well students can "sort the good ________ (64) the bad" on the Internet has become a higher priority for CSU, Roth said.CSU is considering ________ (65) a mandatory assessment test on technological literacy for all freshmen, much as it has required English and math placement tests since the 1980s.Students in freshman seminars at Sacramento State were asked to take the test early in the semester and were expected to finish another round this week to measure their improvement.51 A brought B built C stood D grew52 A about B near C at D by53 A Besides B However C In addition D Doubtfully54 A do B work C make D deal55 A effort B plot C wish D slogan56 A ask B measure C require D demand57 A small B little C broad D partial58 A made B held C managed D administered59 A between B upon C by D with60 A taking B copying C typing D moving61 A pull B push C beat D knock62 A whatever B whoever C whichever D however63 A look at B take up C cope with D serve as64 A out B from C on D of65 A added B adds C adding D add1 A2 B3 C4 A5 C6 A7 D8 B9 D 10 B11 B 12 D 13 A 14 C 15 C16 A 17 B 18 A 19 C 20 C21 B 22 A 23 C 24 D 25 B26 A 27 A 28 D 29 C 30 E31 B 32 A 33 D 34 B 35 C36 A 37 C 38 A 39 D 40 A41 A 42 C 43 C 44 B 45 D46 F 47 E 48 B 49 C 50 A51 D 52 C 53 B 54 A 55 A56 B 57 C 58 D 59 D 60 C61 B 62 A 63 A 64 B 65 C2009年全国专业技术人员职称英语等级考试卫生类B级真题及答案第1部分：词汇选项（第1～15题，每题1分，共15分）下面每个句子中均有1个词或短语划有横线，请为每处划线部分确定1个意义最为接近的选项。
SAT语法真题2011.10
2011年10Section 51. While studying mutations in corn, biologist Barbara McClintock discovered that certain genes that were able to move their positionson chromosomes and control the activity of other genes.(A) that were able(B) that had been able(C) were able(D) able(E) to be able2. Chrysanthemums, lilies, and crocuses are just three types of flowers grew in both European and Asian gardens.(A) flowers grew(B) flowers that grow(C) flowers; their growth(D) flowers, they grow them(E) flowers, they are grown3. Though the Savannah was the first steamship to cross the Atlantic Ocean, it relied on its sails, rather that steam engine, for most of the voyage.(A) it relied(B) they relied(C) but it relied(D) but relying(E) relying4.Richard Axel and Linda B. Buck's research has demonstrated how receptors in the nose detect odor, how receptor cells send information to the brain, also the brain recognizes particular odors.(A) also the brain recognizes particular odors(B) and the brain recognizes particular odors(C) and how the brain recognizes particular odors(D) and how particular odors recognized by the odors(E) then particular odors are recognized by the odors5. After each of the architects have finished to present a plan for the building's renovation, the committee considered the proposals and made its decision.(A) have finished to present(B) have finished presenting(C) has finished presenting(D) had finished to present(E) had finished presenting6. The United States coal market was dominated by Appalachian coal for a century, which was first mined in the 1800s.(A) The United States coal market was dominated by Appalachian coal for a century, which was first mined in the 1800s.(B) First mined in the 1800s was Appalachian coal, it dominated the United States coal market fora century.(C) First mined in the 1800s, Appalachian coal dominated the United States coal market for a century.(D) Appalachian coal, dominating the United States coal market for a century, first mined in the 1800s.(E) Appalachian coal being first mined in the 1800s and dominated the United States coal market for a century.7. With its fast whirling of partners held as if in an embrace, many people were shocked by the waltz when it was introduced around 1800.(A) embrace, many people were shocked by the waltz when it was introduced around 1800(B) embrace, around 1800, many people were shocked when the waltz was introduced(C) embrace, the waltz shocked many people when it was introduced around 1800(D) embrace, the introduction of the waltz, around 1800, shocked many people(E) embrace is why many people were shocked by the waltz when it was introduced around 18008. Cattle ranchers often view the prairie dog as pests, eating pasture grasses and digs holes that can injure cattle.(A) pests, eating(B) pests, they eat(C) pests that eat(D) a pest, although it eats(E) a pest because it eats9. Although one might think that contact lenses are a recent invention, but in fact were developed more than a century ago.(A) but in fact were(B) but they were in fact(C) the fact being that they were(D) they have in fact been(E) they were in fact10. By using a thimble to protect your finger from the needle, the thimble makes sewing easier.(A) the thimble make sewing easier(B) you can sew more easily(C) sewing is easier(D) it can be sewn easier by you(E) it improves the ease of sewing11. Unlike several decades ago, today's librarians teach students to evaluate the accuracy and objectivity of online resources in addition to helping them find particular books.(A) Unlike(B) Unlike them of(C) Unlike those of(D) Contrary to(E) Contrary to those12. The ancient Sumerians wrote(A) on clay tablets, which were(B) either hardened to preserve the writing and(C) left unhardened so that they could be inscribed again(D). No error(E)13.Covering(A) the roof of a building with(B) heat-reflecting plants can dramatically(C) reducethe cost of(D) air-conditioning. No error(E)14. Elizabeth Bishop's unpublished manuscripts contained many unfinished drafts; some she intended(A) to rewrite but others(B) she never meant(C) to publish, having lay(D) them aside as mementoes of the past. No error(E)15.James Houston, whose glass sculptures often depicted(A) Arctic scenes such as fishing or kayaking, drawing(B) his inspiration from(C) Inuit stone carvings he saw(D) while living on Baffin Island. No error(E)16. Studies of home remedies for(A) mild bums have showed(B) that honey has(C) antibacterial and anti-inflammatory properties that may promote(D) healing. No error(E)17.Production delays were notoriously(A) difficult obstacles to overcome(B) until the company adopted(C) new computer technology that works more effective(D) than the old technology. No error(E)18. Either a novel by Isaac Asimov or one by Arthur C. Clarke are(A) going to be discussed(B) at(C) the next meeting of(D) the Science Fiction Book Club. No error(E)19. Larger than(A) the entire state of California, the Chihuahuan Desert is home to(B) approximately(C) 1,000 plant species found nowhere else(D) in the world. No error(E)20. The shimmering appearance for which(A) silk is prized(B) comes from its fibers' prism like structure which allow(C) silk cloth to refract incoming light at different angles(D). No error(E) 21.The biography describes how(A), growing up(B) in a small house with six energetic siblings, Ellis developed a high tolerance for(C) mayhem and learns(D) to accommodate the needs of other people.No error(E)22. Because cell phones are so widely(A) used today, many movie theaters post(B) signs warning(C) that it is(D) not permitted during the movie. No error(E)23. Featured in(A) many New York City landmarks, the vaulted tile ceilings patented by(B) Rafael Guastavinoreflects(C) the influence of Spanish architecture on his(D) style. No error(E) 24.Although(A) snowflakes come in(B) an almost infinite number of(C) designs, its(D) basic form is a six-pointed star. No error(E)25. In recognition to(A) her extraordinary(B) contributions to gospel music, in 1988 the National Endowment for the Arts presented(C) Willie Mae Ford Smith with(D) a National Heritage Award.No error(E)26. Researchers have discovered(A) that a fish, like a human(B), processes(C) some kinds of information with the right side of its brain and other(D) kinds with the left. No error(E)27. New Zealand had fostered(A) a thriving local music scene for decades(B), but it was not until the late 1980s when(C) New Zealand musicians began to reach(D) international audiences. No error(E)28. Because neither of the dolls were(A) in its original box, the pair would not be(B) worth as much as(C) the toy collector had(D) hoped. No error(E)29. The figures cited(A) in the report do not collaborate(B) the author's claim that small hospitals generally provide(C) better patient care than do(D) large ones. No error(E)(1) Should skateboarding be an Olympic event?(2) Many people do not believe it. (3) They object that skateboarding is too new a sport to be included in theOlympic Games. (4)Not only that, they claim that the sport's free-form style and antiestablishment culture are contrary to the Olympic spirit. (5) Skateboarding, they claim, is all about breaking rules, while the Olympic is all aboutplaying by them.(6) In the first place, skateboarding is not particularly new. (7) Its origins can be traced to the 1950s, when the young surfers began riding through the streets of Southern California on flat pieces of wood to which they hadattached steel roller-skate wheels. (8) Skateboarding is older than two current Olympic sports-snowboardBMX cycling-which were not developed until the(9) All three of these sports have relatively high rate of injury.(10) Moreover, skateboarding does not seem nearly as rebellious as it once did. (11) Countries and citiesaround the world have created government-approved skateboarding parks. (12) Skateboarding was becoming a phenomenon of popular culture, with people of all ages playing skateboarding video games at home and watching professional skate6oarding competitions on television. (13) And, despite its reputation as a sport without rules skateboarding has developed standard moves and tries as well as accepted criteria for judging skill and performance.(14)But there is a reason for including skateboarding events in the Olympics that has nothing to do witheither how old or how accepted the sport is. (15) The International Olympic Committee wants to attract young viewers to the Olympic telecasts. (16) It was this design prompted the committee to approve snowboarding for 1998 Winter Games and BMX cycling for the 2008Summer Games.30. In context, which of the following is the best version of the underlined portion of sentence 2 (reproduced below)?Many people do not believe it.(A) (as it is now)(B) agree with them(C) think so(D) have an opinion(E) support this statement31. Which sentence, if placed immediately before sentence 6, would best introduce the second paragraph and link it to the first?(A) People often feel threatened by innovation, and these critics are no different, of course.(B) Faced with these facts, supporters of Olympic skateboarding must adopt a different strategy.(C) Many skateboarders believe that there is more to a sport than just playing by the rules.(D) But perhaps the Olympics should make an exception for extreme sports like skateboarding.(E) None of these objections stands up to careful examination, however.32. In context, which is the best version of the underlined part of sentence 10 (reproduced below)? Moreover, skateboardingdoes not seem nearly as rebellious as it once did.(A) (As it is now)(B) Hopefully, skateboarding(C) In other words, skateboarding(D) Skateboarding, for instance,(E) Skateboarding, by comparison,33. In context, what is best to do with sentence 12 (reproduced below) ?Skateboarding was becoming a phenomenon of popular culture, with people of all ages playing skateboarding video games at home and watching professional skateboarding competitions on television.(A) Change "was becoming" to "has become".(B) Delete "of popular culture".(C) Delete "of all ages".(D) Insert "who were" before "playing".(E) Insert "mainstream" before "television".34. Which of the following sentences, if inserted after sentence 16, would provide the best conclusion for the passage?(A) Like any other television production, telecasts of the 0lympics make a lot of money from advertisers.(B) Given its considerable popularity among young people everywhere, skateboarding should likewise win the committee's approval in the near future.(C) Since these sports were also once considered too extreme for the Olympics, many people still feel that way about skateboarding.(D) Despite the persistent objections of its opponents, skateboarding has been around since the 1950s.(E) Because it requires high levels of skill, athleticism, and creativity, skateboarding requires that its practitioners be in surprisingly good physical condition.35. Which of the following sentences should be deleted from the passage?(A) Sentence 1(B) Sentence 3(C) Sentence 4(D) Sentence 9(E) Sentence 14Section 101. In 1911 the Great Blue Norther, a massive storm in the Midwestern United States, it caused temperatures in some cities to drop more than 60 degrees in a single day.(A) it caused(B) caused(C) causing(D) which caused(E) having caused2. The Galapagos Islands originated when sections of Earth's crust passed over volcanic hot spots, molten lava erupted through those sections, and the lava has cooled to form new landmasses.(A) has cooled to form(B) will cool, forming(C) cooled to form(D) cools and forms(E) cools, forming3. Playing an instrument such as the violin or the piano is a complex activity, it involves the use of several different parts of the brain.(A) activity, it involves(B) activity, with it involving(C) activity, which it involves(D) activity that involves(E) activity and involving4. The final match of the 2006 FIFA World Cup was the most widely viewed sporting event of that year, with an estimated television audience of 715.1 million people worldwide.(A) with an estimated television audience of 715.1 million people(B) the estimated television audience was 715.l million people(C) it was watched by an estimated television audience of 715.l million people(D) and they estimated that 715.l million people watched it on television(E) when an estimated 715.1 million people watching on television5. The ballet company's directors turned down Smith's offer of a huge donation because Smith wanted to control the company not only financially but also will be a decision mak.er in artistic matters.(A) to control the company not only financially but also will be a decision maker in artistic matters(B) controlling the company financially but also be an artistic decision maker(C) control of the company not only in financial matters and also artistic(D) financial control of the company as well as artistically(E) not only financial but also artistic control of the company6. Forgetting to substitute American for British spellings when the editor edited the article, the word "realise" was not changed to "realize."(A) Forgetting to substitute American for British spellings when the editor edited the article(B) Because the editor of the article forgot to substitute American for British spellings(C) Because of forgetting to substitute American for British spellings when editing the article(D) To forget to substitute American for British spellings when editing the article(E) Having forgotten to substitute American for British spellings when editing the article7. In 1933 a group of film actors founded the Screen Actors Guild, a labor union that negotiates fair contracts for actors, in addition protects their legal rights.(A) actors, in addition protects(B) actors, it also protects(C) actors and to protect(D) actors and protects(E) actors; which protects8. Whereas today's censuses estimate the total population of a region, in ancient times it was conducted for other purposes, such as identifying who should pay taxes.(A) in ancient times it was conducted(B) but in ancient times they were conducted(C) conducting censuses was done in ancient times(D) censuses in ancient times were conducted(E) censuses conducted in ancient times9. A wiki is a Web site that uses simple software designed to allow the site's content be altered or changed by anyone who has access.(A) be altered or changed(B) to be altered or be changed(C) to be altered(D) be changed(E) being changed10. Despite their many differences in size and appearance, but every domestic dog breed belongs to the same species and are extremely similar in genetic makeup.(A) but every domestic dog breed belongs(B) but all domestic dog breeds belong(C) every domestic dog breed belongs(D) all domestic dog breeds belong(E) domestic dog breeds all belonging11. The largest city public library in the United States, the New York Public Library contains over10 million books and 10 million manuscripts.(A) States, the New York Public Library contains(B) States, it is the New York Public Library that contains(C) States, contained in the New York Public Library is(D) States is the New York Public Library, contained in it there is(E) States that is the New York Public Library; it contains12. Though the communications company offers high-speed Internet service, they charge exorbitant rates, and customers complain about long delays for technical support.(A) they charge exorbitant rates(B) they charge rates that are exorbitant(C) exorbitant rates are charged by them(D) the rates it charges being exorbitant(E) it charges exorbitant rates13. Originally built as a church, later converted to a Mosque, and now used as a museum, Hagia Sophia, in Istanbul, Turkey, is one of the greatest surviving examples of Byzantine architecture.(A) later converted to a mosque, and(B) later converted to a mosque and is(C) was later converted to a mosque, and(D) was later converted to a mosque and is(E) it was later converted to a mosque and is14. Having lived in Paris for six years, Martha's fluency in French is not surprising.(A) Martha's fluency in French is not surprising(B) Martha 's being fluent in French is not surprising(C) Martha's French is, not surprisingly, fluent(D) Martha, whose fluency in French is not surprising(E) Martha is, not surprisingly, fluent in French。
DPS050A186A_Bipane_Specification_20150518_v4
(0.020)
(26.0) 60 fFLM x 2
Frame Frequency TP Frame Frequency
fFLM TPfFLM
-
Notes (1) VDDI=1.8V, AVDD=3.3V, VDDF-=2.5V, fFLM=60Hz, Column inversion mode, MIPI Video mode. (2) TP active mode. （No fingers) (3) The value is a frame frequency when the data of Item as follows is set to the register. When changing setting data, please contact us. (4) VDDF voltage level is depended on Flash IF spec. VDDF<AVDD Parameter
TCLK-PRE
300 8UI 38 60 50
95
105+12UI
Japan Display Inc.
Date
Feb. 26, 2015
Sh. No.
DPS050A186A
Page
5-1/1
6. OPTICAL CHARACTERISTICS
LCD (BACKLIGHT ON) Item Transmittance Viewing Angle Contrast Ratio Red Green Color Tone (Primary Color) Blue White NTSC Ratio Response Time Measurement Conditions Measurement environment Ambient temperature Power supply voltage Backlight Polarizer Symbol T φ1+φ2 CR x y x y x y x y tr+tf Condition φ=0°, θ=0° θ=0°, CR>10 θ=90°, CR>10 φ=0°, θ=0° Min (2.85) 700 (0.607) (0.301) (0.267) (0.565) (0.125) (0.028) (0.260) (0.282) 65 Typ 3.48 160 160 1000 (0.637) (0.331) (0.297) (0.595) (0.155) (0.058) (0.290) (0.312) 70 25 Max (0.667) (0.361) (0.327) (0.625) (0.185) (0.088) (0.320) (0.342) Unit % deg Note
非等位基因
非等位基因概述非等位基因是指同一基因座上的不同等位基因。
等位基因是指在某个给定的基因座上，可以存在多种不同的变体。
每个个体继承了一对等位基因，一对等位基因可能会导致不同的表型表达。
非等位基因的存在使得遗传学研究更加复杂，因为不同的等位基因会对个体的表型产生不同的影响。
背景在生物学中，基因座是指染色体上一个特定的位置，该位置上的基因决定了某个特征的表达方式。
每个基因座上可以有多种不同的等位基因。
等位基因是指在某个特定基因座上的不同基因变体。
每个个体都会继承一对等位基因，通过这对等位基因的不同组合，决定了个体的表型。
然而，并非所有基因座上的等位基因都具有相同的表现型。
非等位基因的影响非等位基因的存在导致不同等位基因会对个体表型产生不同的影响。
有些非等位基因会表现出显性效应，也就是说，当个体继承了一个突变的等位基因时，即使同时继承了一个正常的等位基因，但显性效应会使得突变的等位基因的表型表达得到体现。
相反，有些非等位基因会表现出隐性效应，当个体继承了两个突变的等位基因时，才会表现出突变的表型。
除了显性和隐性效应之外，非等位基因还可能发生两种其他类型的表型效应。
一种是共显效应，当个体继承了两个不同的突变等位基因时，在表型表达上会表现出一种新的特征，这个特征并不是单个突变等位基因所能导致的。
另一种是部分显性效应，当个体继承了两个不同的突变等位基因时，表型表达将介于两个单独突变等位基因的表型之间。
重组和非等位基因重组是指两个不同的染色体交换部分基因序列的过程。
在重组的过程中，非等位基因可能会发生改变，导致新的等位基因组合形成。
这一过程使得非等位基因的表型效应更加复杂，因为新的等位基因可能将不同基因座的效应组合起来。
非等位基因的重要性非等位基因对生物的适应性和多样性起着重要作用。
通过对等位基因的各种组合的研究，人们可以更好地理解基因与表型之间的关系，并揭示遗传变异对物种适应环境的重要性。
总结非等位基因是指同一基因座上的不同等位基因。
Silencing of lMALAT1 by miR-101 and miR-217 inhibits proliferation, migration and invisave of ESCC
and Ming Yang Liqing Zhou, Changchun Zhou, Qipeng Yuan Sichong Han, Xiaohu Tang, Yunxia Ge, Xinyu Wang, Meng Li, Zhiqiong Wang, esophageal squamous cell carcinoma cells proliferation, migration and invasion of by miR-101 and miR-217inhibits Silencing of long noncoding RNA MALAT1RNA: published online December 23, 2014J. Biol. Chem.10.1074/jbc.M114.596866Access the most updated version of this article at doi:.JBC Affinity Sites Find articles, minireviews, Reflections and Classics on similar topics on the Alerts:When a correction for this article is posted • When this article is cited • to choose from all of JBC's e-mail alertsClick here /content/early/2014/12/23/jbc.M114.596866.full.html#ref-list-1This article cites 0 references, 0 of which can be accessed free at at Biomedical Library, UCSD on January 1, 2015/Downloaded from1Silencing of long noncoding RNA MALAT1 by miR-101 and miR-217 inhibits proliferation, migration and invasion of esophageal squamous cell carcinoma cellsXinyu Wang 1, Meng Li 1, Zhiqiong Wang 1, Sichong Han 1, Xiaohu Tang 1, Yunxia Ge 1, Liqing Zhou 2, Changchun Zhou 3, Qipeng Yuan 1, Ming Yang 1,*1State Key Laboratory of Chemical Resource Engineering, Beijing Laboratory of Biomedical Materials, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China; 2Department of Radiation Oncology, Huaian No. 2 Hospital, Huaian, Jiangsu Province, China; 3Clinical Laboratory, Shandong Cancer Hospital, Shandong Academy of Medical Sciences, Jinan, Shandong Province, China*To whom correspondence should be addressed : Ming Yang, PhD, Professor, College of Life Science and Technology, Beijing University of Chemical Technology, P. O. Box 53, Beijing 100029, China. Tel: 86-10-64447747, Fax: 86-10-64437610; E-mail: yangm@.Running title: MiR-101 and miR-217 silence MALAT1 in ESCCManuscript category: Research ArticleFunding supports:National Natural Science Foundation of China (31271382, 91229126& 81201586); Beijing Higher Education Young Elite Teacher Project (YETP0521); the Fundamental Research Funds for the Central Universities (YS1407); the open project of State Key Laboratory of Molecular Oncology (SKL-KF-2013-03); Program for Changjiang Scholars and Innovative Research Team in University (IRT13045).The study sponsor was not involved in the study design in the collection, analysis, and interpretation of date.Keywords: MALAT1; miR-101; miR-217; esophageal squamous cell carcinoma/cgi/doi/10.1074/jbc.M114.596866The latest version is at JBC Papers in Press. Published on December 23, 2014 as Manuscript M114.596866 Copyright 2014 by The American Society for Biochemistry and Molecular Biology, Inc. at Biomedical Library, UCSD on January 1, 2015/Downloaded fromCapsuleBackground: MALAT1, a highly conserved long non-coding RNA (lncRNA), acts as oncogene in multiple human cancers.Results: miR-101 and miR-217 can silence MALAT1 expression and, then, inhibit esophageal cancer proliferation, migration and invasion. Conclusion: Tumor suppressor miR-101 and miR-217 can negatively regulate MALAT1 expression.Significance: These data provide a new mechanism for MALAT1 regulation.ABSTRACTMALAT1, a highly conserved long noncoding RNA, is deregulated in several types of cancers. However, its role in esophageal squamous cell carcinoma (ESCC) and its posttranscriptional regulation remain poorly understood. In this study, we provide first evidences that a posttranscriptional regulation mechanism of MALAT1 by miR-101 and miR-217 exists in ESCC cells. This posttranscriptional silencing of MALAT1 could significantly suppress the proliferation of ESCC cells through the arrest of G2/M cell cycle, which may be due to MALAT1-mediated upregulation of P21 and P27 expression and the inhibition of B-MYB expression. Moreover, we also found the abilities of migration and invasion of ESCC cells were inhibited after overexpression of miR-101, miR-217 or MALAT1 siRNA. This might be attributed to the deregulation of down-stream genes of MALAT1, such as MIA2,HNF4G, ROBO1, CCT4 and CTHRC1. A significant negative correlation exists betweenmiR-101 or miR-217 and MALAT1 in 42 pairsof ESCC tissue samples and adjacent normaltissues. Mice exnograft data also support thetumor suppressor role of both miRNAs inESCC.at Biomedical Library, UCSD on January 1, 2015/Downloaded from23Introduction Esophageal squamous cell carcinoma (ESCC) is one of the most common and lethal malignancies all around the world. In eastern Asia, ESCC shows a relatively high morbidity and mortality compared to Western countries (1). Epidemiological evidences indicate that heavy alcohol drinking, tobacco smoking, micronutrient deficiency and dietary carcinogen exposure are major environmental risk factors of this fatal disease (2, 3). However, only a part of exposed individuals eventually develop ESCC, demonstrating that host genetic components may also contribute to ESCC etiology (2-7). Multiple cancer causal protein-coding genes, either as oncogenes or tumor suppressors, have been identified in the majority of cancer-associated human genomic loci (8). Accumulated evidences indicate that noncoding RNA (ncRNA) genes also play a crucial role in malignant transformation and/or cancer progression (9-11). Among different kind of ncRNAs, the discovery of endogenous ~22 nucleotides ncRNAs—named microRNAs (miRNAs)—not only disclosed a new layer of gene expression regulation, but also revealed the direct involvement of ncRNAs in tumorigenesis (12, 13). Recently, many long ncRNAs (lncRNAs) ranging in size from several hundred base pairs (bp)to tens of thousands bp, have been identified as a new class of cancer-associated ncRNAs in human (9-11). Among over 3000 human lncRNAs, less than 1% have been functionally characterized (14). Metastasis associated in lung adenocarcinoma transcript 1 (MALAT1; also known as NEAT2) is a highly conserved mRNA-like lncRNA, which was originally identified with high expression in metastatic non-small-cell lung cancer (NSCLC)(15). It has also been found that MALAT1 is overexpressed in many other human malignancies, including breast, pancreas, colon, prostate and liver (16). Functional studies showed that itsderegulation influences proliferation, invasion and/or metastasis of multiple cancer cells (17-23). Therefore, fine-regulation of MALAT1 is critical for cancer development.Interestingly, lncRNAs may potentially interact with miRNAs and modulate each other’s expression. In one hand, lncRNAs may function as a competing endogenous RNAs (ceRNA) to miRNAs. In another hand, miRNAs could inhibit expression of lncRNAs through Argonaute 2 (Ago2)-mediated pathway (24-28). However, how lncRNA MALAT1 is regulated by miRNAs at the transcriptional level and its involvement in ESCCat Biomedical Library, UCSD on January 1, 2015/Downloaded fromremains largely unknown. In the current study, we found that miR-101 and miR-217 could silence MALAT1 in ESCC and this posttranscriptional regulation may lead to inhibition of growth, invasion and metastasis of ESCC cells.Materials and MethodsQuantitative real-time PCRTotal RNA was isolated from either culture cells or tissue samples using Trizol reagent (Invitrogen, US). RNA samples were reverse transcribed (RT) into cDNA with different RT primers using Revert Ace kit (TOYOBO, Japan). PCR primers used for detecting MALAT1, β-actin and MALAT1 downstream genes (p21, p27, B-MYB, MIA2, HNF4G, ROBO1, CCT4 and CTHRC1) were described previously (17, 18, 23). Stem-loop RT-PCR primers for human miR-101, miR-217 and U6 were synthesized by Ribobio (China). For miR-101, miR-217 and U6 detection, RNA samples were reverse transcribed into cDNA using Revert Ace transcriptase by specific stem-loop RT primers according to the manufacturer’s instruction. The stem-loop PCR was performed as previously described (26). Transcript levels were measured against an endogenous control by qPCR using the SYBR®Green I fluorogenic dye using the Mastercycler eprealplex system (Eppendorf, Germany).Plasmid constructionTotal RNA was extracted from KYSE30 cellline and reverse transcribed into cDNA. Thesequence corresponding to the wild-type MALAT13’ end was amplified by PCR and inserted betweenthe Xba I restriction site of the reporter plasmidpGL3-control (Promega, US). The primers usedwere as follows: 5’-AACTCTAGAGCTTGGCTCTTCCTTCTGTTC-3’/5’-AACTCTAGACCTCAACACTCAGCCTTTATC-3’. The plasmid was named aspGL3-MAL. For construction of MALAT1 reportergene plasmids with mutant miR-101 binding siteor mutant miR-217 binding site, QuikChangeSite-Directed Mutagenesis kit (Stratagene, US)was used according to the manufacture’s construction. These mutant plasmids were namedas pGL3-mut101 or pGL3-mut217. Wild-type andmutant inserts were confirmed by DNA sequencing.Dual luciferase reporter gene assaysA firefly luciferase reporter plasmid(pGL3-MAL, pGL3-mut101 or pGL3-mut217), arenilla luciferase vector (pRL-SV40, Promega)plus small RNAs (miR-101 mimics, miR-217at Biomedical Library, UCSD on January 1, 2015/Downloaded from45mimics or negative control RNAs) were co-transfected into KYSE30, KYSE150 or KYSE450 cells with Lipofectamine ® 2000 (Invitrogen). Three independent transfection experiments were performed and each was done in triplicate. Firefly luciferase activities derived from pGL3-control derived plasmids were normalized to renilla luciferase activity from pRL-SV40 using a luciferase assay system (Promega) as reported previously (29, 30). Cell proliferation assays Human ESCC cell lines (KYSE30, KYSE150 and KYSE450) were cultured in RMPI 1640 medium (Invitrogen) supplemented with penicillin-streptomycin and 10% fetal bovin serum (Hyclone, US) at 37°C with 5% CO 2. KYSE30 and KYSE150 cells were seeded in a 12-well plate at a density of 1×105 cells per well. KYSE450 cells were seeded in a 12-well plate at a density of 2×105 cells per well. Cells were transfected with 10nM miR-101 mimics, miR-217 mimics, negative control RNA (NC) or MALAT1 siRNAs (siM) (Genepharma, China) combined with Lipofectamine ® RNAi Max (Invitrogen). Cells were then harvested by trypsin digestion, washed by cold PBS twice, dyed with trypan blue and counted under microscopy at 24h and 48h after transfection.Colony formation assaysA total of 8,000 KYSE150 cells were transfected with 10nM NC RNA, miR-101 mimics, miR-217 mimics or siM into a 6-well cell culture plate. After 14 days, cells were washed with cold PBS twice and fixed with 3.7% formaldehyde. After cancer cells were dyed with crystal violet, colony number in each well was counted.Wound-healing assays and transwell assays When reaching ~90% confluence, the celllayer was scratched. Cells were then continued cultured at 37°C. The average extent of wound closure was quantified. During transwell assays, the transwell chambers were coated with 100 μl BD Matrigel™ overnight in cell incubator. Cells (1×104 cells in 200 μl medium with 0.2% BSA) transfected with 10nM miR-101 mimics, miR-217 mimics, siM or NC were added to upper transwell chambers (pore 8μm, Corning). A medium containing 10% FBS (650μl) was added to the lower wells. After 48h incubation, cells were fixed and stained, and the nonmigratory cells were scraped from the upper part of the filter. Cells migrated to the lower wells through pores were stained with 0.2% crystal violet solution and counted.at Biomedical Library, UCSD on January 1, 2015/Downloaded fromFlow CytometryCells were transfected with 10nM miR-101 mimics, miR-217 mimics, or NC and harvested at 48h after transfection. After washing with cold PBS twice, cells were fixed with ethanol at -20°C overnight and washed with cold PBS twice again. After treated with RNase A at 37°C for 0.5h and dyed with PI, the samples were detected with the FACSCalibur flow cytometer (FCM) (BD Biosciences). During apoptosis assays, apoptosis was determined using the Alexa Fluor® 488 annexin V/Dead Cell Apoptosis Kit (Invitrogen) with the FACSCalibur FCM.Tumor tissue specimensTwenty-four pairs of ESCC tissues and esophagus normal tissues adjacent to the tumors were obtained from surgically removed specimens of ESCC patients in Shandong Cancer Hospital, Shandong Academy of Medical Sciences. Eighteen pairs of ESCC and normal tissues were obtained from Huaian No. 2 Hospital. The tumor tissues and adjacent normal tissues were frozen in liquid nitrogen after resection. No patients in the current study received chemotherapy or radiation therapy before the surgery. This study was approved by the institutional Review Boards. A part of the tissue samples has been reported previously (31, 32). ESCC XenograftFive-week old female nude BALB/c micewere purchased from Vital River Laboratory (Beijing, China). To evaluate the tumor suppressorrole of miR-101 and miR-217 in vivo, 1×107KYSE150 cells transfected with 30 nM miR-101,miR-217 or siM were inoculated subcutaneouslyinto fossa axillaris of twelve nude mice (n =3 per group). Tumor volumes were measured three timesa week. All procedures involving mice were approved by the institutional Review Board ofHuaian No. 2 Hospital.Statistical analysesAll data are presented as means ± standarddeviation (SD) unless stressed. Student’s t test wasused to examine the differences in luciferasereporter gene expression, and Spearman’s correlation was used to test the significance of association between miR-101 or miR-217 expression and MALAT1 RNA expression. P<0.05was considered statistically significant. All analyses were performed with SPSS softwarepackage (Version 16.0, SPSS Inc.).ResultsIdentification of candidate miRNAs targetingMALAT1at Biomedical Library, UCSD on January 1, 2015/Downloaded from67Photoactivatable-Ribonucleoside-Enhan ced Crosslinking and Immunoprecipitation (PAR-CLIP) is a biochemical method used for identifying the binding sites of cellular RNA-binding proteins (RBPs) and microRNA-containing ribonucleoprotein complexes (miRNPs). Using this method, Harfner et al draw a precise map binding sites of Ago proteins across the transcriptome of HEK293 cells (33). Based on these data, Jalali et al evaluated s ystematic transcriptome wide lncRNA-miRNA interactions (26), which provide a good resource for exploring the potential miRNA-dependent lncRNA regulation in human cells . Interestingly, we found that Ago2 protein probably binds to the 3’ end region (from 6615nt to 6650nt) of MALAT1 lncRNA in human cells (Figure 1A). This MALAT1 6615nt to 6650nt region was highly conserved in different mammals (Figure 1A), suggesting its potential function significance as a posttranscriptional regulation region. MiRCode () was then utilized to predict potential miRNA candidates which may target this region. As a result, miR-101, miR-217, miR-383 and miR-503 were identified as candidates for further evaluations (Figure 1A). To verified whether MALAT1 might be regulated by miRNAs, we firstly knocked-down Ago2 (the catalytic subunit of RNA-induced silencing complex, RISC) as well as Dicer (an essential enzyme during miRNA maturing) and examined expression changes of MALAT1 in ESCC cells (Figure 1B and 1C). As expected, we found 1.2-fold to 1.5-fold elevated MALAT1 RNA expression following depressed Ago2 expression in KYSE30, KYSE150 and KYSE450 cells. Also, there was a 1.2-fold to 1.4-fold increased MALAT1 RNA expression after inhibition of Dicer expression in these cell lines. These results gave some clues that miRNAs might participate in MALAT1 regulation.We then tested the possible regulation of MALAT1 RNA expression by miR-101, miR-217, miR-383 and miR-503 in ESCC cells (Figure 1D). Although overexpression of miR-101 and miR-217 could significantly inhibit MALA T1 RNA expression, miR-383 and miR-503 showed little impact. To validate this observation, antagomirs of miR-101 and miR-217 were employed to inhibit endogenous miR-101 and miR-217 expression. We found that a 1.2-fold to 1.6-fold up-regulation of MALAT1 RNA expression in ESCC cells after transfection with antagomirs of both miRNAs(Figure 1E). Given the relative low endogenousat Biomedical Library, UCSD on January 1, 2015/Downloaded fromexpression of miR-101 and miR-217 in ESCC cell lines, it was possible that further inhibition of miR-101 and miR-217 by antagomirs only yielded a marginal effect on MALAT1 RNA expression. Whereas, their low expression in ECSS cells also provided a clue that miR-101 and miR-217 might be tumor suppressors.Interaction of miR-101 or miR-217 and the MALAT1 RNATo examine the potential miRNA-lincRNA interaction experimentally, a 343bp human MALAT1 3' end region (from 6423nt to 6765nt) was subcloned downstream of the firefly luciferase gene (named as pGL3-MAL) and co-transfected into KYSE30, KYSE150 and KYSE450 cells with miR-101 mimics, miR-217 mimics or NC RNA. MiR-101 produced a 42.8%, 58.4% and 41.5% decrease in relative luciferase activity compared with NC RNA transfected KYSE30, KYSE150 and KYSE450 cells (all P<0.05)(Figure 2B, left panel). Similarly, there was 30.3%, 86.7% and 35.1% decreased relative luciferase activity in these ESCC cells with miR-217 overexpression compared to the NC RNA group (all P<0.05)(Figure 2B, left panel). We also measured firefly luciferase mRNA expression with RT-qPCR. As expected, pGL3-MAL firefly luciferase mRNA level was significantly inhibited by miR-101 or miR-217(Figure 2B, right panel). An analogous reporterwith point substitutions disrupting the target sitesof miR-101 or miR-217 (Figure 2A) was alsoco-transfected with miR-101 mimics, miR-217mimics or NC RNA. There was no significant decrease in relative luciferase activity for cells transfected with miR-101 or miR-217 mimics compared with NC RNA-transfected cells (Figure2B, left panel).MiR-101 and miR-217 inhibit proliferation ofESCC cells by G2/M cell cycle arrestIt has been reported that lncRNA MALAT1can modulate cellular proliferation through regulating cell cycle progression. Therefore,miR-101 and miR-217 may also be involved incontrol of ESCC cell growth through silencingMALAT1 RNA expression. We found thatmiR-101, miR-217 or MALAT1 siRNA could significantly inhibit proliferation of KYSE150 andKYSE30 cells in both a dose-dependent and time dependent way (all P<0.01) (Figure 3A). Colonyformation assays also support the tumor suppressorrole of both miRNAs (Figure 3B).To gain insight into the functional relevanceof miR-101 and miR-217 through MALAT1at Biomedical Library, UCSD on January 1, 2015/Downloaded from8depletion, we examined the impacts of these miRNAs on KYSE30 cell cycle progression and apoptosis (Figure 3C). Compared with NC RNA-transfected KYSE30 cells, both miR-101 and miR-217 could result in a significantly reduced G1 population (NC, 59.4%; miR-101, 31.7%; miR-217, 32.1%), marginally increased replication (S-phase) (NC, 30.9%; miR-101, 34.2%; miR-217, 42.5%) and significantly elevated G2/M population (NC, 9.6%; miR-101, 34.1%; miR-217, 25.4%). Similar results have been found in KYSE150 cells (Figure 3C and 3D). However, no significant miRNA-induced apoptosis was observed in both celllines (data not shown). Moreover, we didn’t observe a growth depression in KYSE450 cells (data not shown).MiR-101 and miR-217 inhibit migration and invasion of ESCC cellsSince impacts of lncRNA MALAT1 on ESCC invasion and metastasis were still largely unclear, we investigated how siM, miR-101 and miR-217 regulate migration and invasion of ESCC cells. The wound-healing assays demonstrated that siM, miR-101 and miR-217 impaired the motility of the KYSE30, KYSE150 and KYSE450 cells compared to control cells transfected with NC RNA (Figure 4A). Next, the impact of miR-101 and miR-217 on invasiveness of KYSE30,KYSE150 and KYSE450 cells was determinedusing the Matrigel invasion assay system. Reducedinvasion ability of ESCC cells was observed afterelevated expression of miR-101 and miR-217(Figure 4B). In line with this, MALAT1 siRNA canalso inhibit the invasion of these ESCC cells(Figure 4B). We also confirmed this observationusing antagomirs of miR-101 and miR-217 andfound enhanced invasion ability of ESCC cells transfected with these antagomirs (Figure 4B).MiR-101 and miR-217 modulate expression ofMALAT1 downstream genesConsidering the regulation of miR-101 andmiR-217 on cell cycle progression as well as metastasis of ESCC cells, we examined expressionof multiple MALAT1 downstream genes involvedin cell cycle control (p21, p27 and B-MYB) and metastasis regulation (MIA2, ROBO1, CTHRC1and CCT4). Neither miR-101 nor miR-217 hasbeen proven or has potential binding sites in thesegenes predicted by Targetscan. We found that overexpression of miR-101 and miR-217 or siMup-regulated expression of p21 and p27 andinhibited B-MYB expression in both KYSE30 andKYSE150 cell lines but not in KYSE450, whichwas consistent with our results on how theseat Biomedical Library, UCSD on January 1, 2015/Downloaded from9miRNAs influence ESCC cell proliferation and cell cycle. Moreover, miR-101, miR-217 or MALAT1 siRNA could not only increase expression of MIA2, HNF4G and ROBO1 which are negative regulators of migration and invasion, but also depress expression of CCT4 and CTHRC1 which are positive regulators of metastasis, in all three ESCC cell lines.MiR-101 and miR-217 are negatively correlated with MALAT1 RNA expression in ESCC tissues We further examined expression of miR-101, miR-217 and lncRNA MALAT1 in 42 pairs of ESCC tissue samples and adjacent normal tissues from two different medical centers. For Shandong cohort, significant up-regulation of MALAT1 in ESCC tissues was observed compared to normal tissues (P<0.01) (Figure 6A). There was significant down-regulation of miR-101 or miR-217 in ESCC specimens than normal tissues (Figure 6A). Interesting, we found significant negative correlation between miR-101 or miR-217 expression and MALAT1 RNA expression in ESCC or normal specimens using Spearman’s correlation tests (all P<0.05) (Figure 6A). Similar results were found in Huaian cohort (Figure 6B). MiR-101 and miR-217 inhibit ESCC growth in vivoWe found that the growth of tumors frommiR-101–up-regulated or miR-217–up-regulated xenografts was inhibited significantly, comparedwith that of tumors formed from control xenograftsafter 2 weeks (both P < 0.01) (Figure 7A and 7B).The growth of tumors from MALAT1–down-regulated xenografts was alsoinhibited significantly when compared with that oftumors formed from control xenografts (P < 0.01)(Figure 7A and 7B). However, there were no significant differences of mice weight between controls, miRNAs or siM treated groups (Figure7C).DiscussionAlthough lncRNA MALAT1 has been investigated in multiple human cancers (15, 17-23),little is known about its involvement and regulation in ESCC development. Our results demonstrate that an Ago2-dependent posttranscriptional regulation of MALAT1 bymiR-101 and miR-217 exists in ESCC cells for thefirst time. Data from human malignant or normal esophageal tissues strongly support this observation since there was significantly negative correlation between these two miRNAs expressionlevel and MALAT1 RNA expression level. Thisat Biomedical Library, UCSD on January 1, 2015/Downloaded from10posttranscriptional regulation of MALAT1 could lead to significantly depressed proliferation, migration and invasion abilities of ESCC cells, assuming the tumor suppressor role of miR-101 and miR-217.As a highly conserved lncRNA across mammalian species, MALAT1 shows extreme abundance in many human cancers, underlining its functional importance during carcinogenesis. It has been shown that MALAT1 may play its part through several different mechanisms. The 3’ end of MALAT1 could be cleaved by RNase P and RNase Z, which produces the cytoplasmic mascRNA (an new tRNA-like ncRNA) (34). After localizing to nuclear speckles (35), MALAT1 might modulate alternative splicing of a subset of pre-mRNAs by regulating serine/arginine splicing factors activity (36). Moreover, MALAT1 can bind to CBX4 (Chromobox homolog 4), also referred to as Pc2 (Polycomb 2), a component of the Polycomb Repressive Complex 1 (PRC1). This interaction controls the re-localization of PRC1 on interchromatin granules, and silences or actives gene expression (37). In this way, MALAT1 influences proliferation, invasion and migration of cancer cells through regulation of multiple known downstream genes, including several cell cycle control genes (p21, p27 and B-MYB) and metastasis related genes (MIA2, ROBO1,CTHRC1 and CCT4) which we examined in thisstudy.Our data revealed that lncRNAs can be regulated by miRNAs at the posttranscriptionallevel. Dicer is a key enzyme during miRNA maturation. Therefore, knock-down of Dicer expression would result in decreased miRNAslevel in cells. Consistent with this, we found increased MALAT1 RNA expression after Dicer depression in ESCC cells. Additionally, since Ago2is essential for incorporation of mature miRNAsinto RISC, decreased Ago2 expression might leadto attenuated function of miRNAs. In accordancewith this, we observed increased MALAT1 RNA expression after Ago2 silencing, which might bedue to inhibition of miR-101 and miR-217 function. Interestingly, Leucci et al. and Han et al.reported that miR-9 and miR-125b can targetMALAT1 for degradation (27,28), which alsosupports the hypothesis that miRNAs are involvedin regulation of lncRNA MALAT1.As an important tumor-suppressive miRNA,miR-101 takes part in development of multiplehuman cancers through targeting several genesincluding EZH2, Cox-2, Mcl-1 and Fos (38-40).at Biomedical Library, UCSD on January 1, 2015/Downloaded from1112Similarly, it has been reported that miR-217 could function as a tumor suppressor in pancreatic ductal adenocarcinoma and clear cell renal cell carcinoma(41, 42). However, the role of miR-101 ormiR-217 in ESCC is still largely unclear. Ourresults indicate that miR-101 and miR-217 act asvital tumor suppressors at least partially throughsilencing MALAT1 in ESCC, which are consistentwith their functions in other malignancies.In the current study, KYSE450 cells did notbehave like other cells, which may be due todifferent ESCC celllines are from differentcancer patients with different geneticbackgrounds. It is quite common to observecellular behavior discrepancies amongdifferent celllines after same treatment eventhey belong to same type of malignancy.Taken together, we identified lncRNAMALAT1 as a novel target of miR-101 andmiR-217. As a result, this posttranscriptionalregulation shows a significant impact onproliferation, invasion and metastasis of ESCCcells. Our findings highlight the interactionbetween miRNAs and lncRNA MALAT1 duringtumorigenesis and progression of esophageal cells.AcknowledgmentsWe thank Dr. Gwo-Shu Mary Lee of Dana-FarberCancer Institute, Harvard Medical School for the comments and critically reading the manuscript. at Biomedical Library, UCSD on January 1, 2015/Downloaded fromReferences1. Jemal, A., Siegel, R., Ward, E., Hao, Y., Xu, J., and Thun, M. J. (2009) Cancer statistics, 2009.CA Cancer J Clin59, 225-2492. Gao, Y. T., McLaughlin, J. K., Blot, W. J., Ji, B. T., Benichou, J., Dai, Q., and Fraumeni, J. F.,Jr. (1994) Risk factors for esophageal cancer in Shanghai, China. I. Role of cigarette smoking and alcohol drinking. Int J Cancer58, 192-1963. Hu, J., Nyren, O., Wolk, A., Bergstrom, R., Yuen, J., Adami, H. O., Guo, L., Li, H., Huang, G.,Xu, X., and et al. (1994) Risk factors for oesophageal cancer in northeast China. Int J Cancer 57, 38-464. Wu, C., Hu, Z., He, Z., Jia, W., Wang, F., Zhou, Y., Liu, Z., Zhan, Q., Liu, Y., Yu, D., Zhai, K.,Chang, J., Qiao, Y., Jin, G., Shen, Y., Guo, C., Fu, J., Miao, X., Tan, W., Shen, H., Ke, Y., Zeng, Y., Wu, T., and Lin, D. (2011) Genome-wide association study identifies three new susceptibility loci for esophageal squamous-cell carcinoma in Chinese populations. Nat Genet 43, 679-6845. Wu, C., Kraft, P., Zhai, K., Chang, J., Wang, Z., Li, Y., Hu, Z., He, Z., Jia, W., Abnet, C. C.,Liang, L., Hu, N., Miao, X., Zhou, Y., Liu, Z., Zhan, Q., Liu, Y., Qiao, Y., Jin, G., Guo, C., Lu,C., Yang, H., Fu, J., Yu,D., Freedman, N. D., Ding, T., Tan, W., Goldstein, A. M., Wu, T.,Shen, H., Ke, Y., Zeng, Y., Chanock, S. J., Taylor, P. R., and Lin, D. (2012) Genome-wide association analyses of esophageal squamous cell carcinoma in Chinese identify multiple susceptibility loci and gene-environment interactions. Nat Genet44, 1090-10976. Wang, L. D., Zhou, F. Y., Li, X. M., Sun, L. D., Song, X., Jin, Y., Li, J. M., Kong, G. Q., Qi,H., Cui, J., Zhang, L. Q., Yang, J. Z., Li, J. L., Li, X. C., Ren, J. L., Liu, Z. C., Gao, W. J.,Yuan, L., Wei, W., Zhang, Y. R., Wang, W. P., Sheyhidin, I., Li, F., Chen, B. P., Ren, S. W., Liu,B., Li, D., Ku, J. W., Fan, Z. M., Zhou, S. L., Guo, Z. G., Zhao, X. K., Liu, N., Ai, Y. H., Shen,F. F., Cui, W. Y., Song, S., Guo, T., Huang, J., Yuan, C., Wu, Y., Yue, W. B., Feng, C. W., Li, H.L., Wang, Y., Tian, J. Y., Lu, Y., Yuan, Y., Zhu, W. L., Liu, M., Fu, W. J., Yang, X., Wang, H. J., Han, S. L., Chen, J., Han, M., Wang, H. Y., Zhang, P., Dong, J. C., Xing, G. L., Wang, R., Guo, M., Chang, Z. W., Liu, H. L., Guo, L., Yuan, Z. Q., Liu, H., Lu, Q., Yang, L. Q., Zhu, F. G., Yang, X. F., Feng, X. S., Wang, Z., Li, Y., Gao, S. G., Qige, Q., Bai, L. T., Yang, W. J., Lei, G.Y., Shen, Z. Y., Chen, L. Q., Li, E. M., Xu, L. Y., Wu, Z. Y., Cao, W. K., Wang, J. P., Bao, Z.Q., Chen, J. L., Ding, G. C., Zhuang, X., Zhou, Y. F., Zheng, H. F., Zhang, Z., Zuo, X. B., Dong, Z. M., Fan, D. M., He, X., Wang, J., Zhou, Q., Zhang, Q. X., Jiao, X. Y., Lian, S. Y., Ji,A. F., Lu, X. M., Wang, J. S., Chang, F.B., Lu,C.D., Chen, Z. G., Miao, J. J., Fan, Z. L., Lin,R. B., Liu, T. J., Wei, J. C., Kong, Q. P., Lan, Y., Fan, Y. J., Gao, F. S., Wang, T. Y., Xie, D., Chen, S. Q., Yang, W. C., Hong, J. Y., Wang, L., Qiu, S. L., Cai, Z. M., and Zhang, X. J. (2010) Genome-wide association study of esophageal squamous cell carcinoma in Chinese subjects identifies susceptibility loci at PLCE1 and C20orf54. Nat Genet42, 759-7637. Abnet, C. C., Freedman, N. D., Hu, N., Wang, Z., Yu, K., Shu, X. O., Yuan, J. M., Zheng, W.,Dawsey, S. M., Dong, L. M., Lee, M. P., Ding, T., Qiao, Y. L., Gao, Y. T., Koh, W. P., Xiang, Y.B., Tang, Z. Z., Fan, J. H., Wang,C., Wheeler, W., Gail, M. H., Yeager, M., Yuenger, J.,Hutchinson, A., Jacobs, K. B., Giffen, C. A., Burdett, L., Fraumeni, J. F., Jr., Tucker, M. A., Chow, W. H., Goldstein, A. M., Chanock, S. J., and Taylor, P. R. (2010) A shared susceptibility locus in PLCE1 at 10q23 for gastric adenocarcinoma and esophageal squamous cell carcinoma.Nat Genet42, 764-7678. Eichler, E. E., Flint, J., Gibson, G., Kong, A., Leal, S. M., Moore, J. H., and Nadeau, J. H.(2010) Missing heritability and strategies for finding the underlying causes of complex disease.Nat Rev Genet11, 446-4509. Esteller, M. (2011) Non-coding RNAs in human disease. Nat Rev Genet12, 861-87410. Tsai, M. C., Spitale, R. C., and Chang, H. Y. (2011) Long intergenic noncoding RNAs: newlinks in cancer progression. Cancer Res71, 3-711. Rinn, J. L., and Chang, H. Y. (2012) Genome regulation by long noncoding RNAs. Annu RevBiochem81, 145-16612. Ambros, V. (2001) microRNAs: tiny regulators with great potential. Cell107, 823-826 at Biomedical Library, UCSD on January 1, 2015/ Downloaded from。
2011年上学期高二期末考试试题
2010 – 2011学年度第二学期期末考试试题高一英语本试卷分第一卷（选择题）和第二卷（非选择题）两部分。
满分150分；考试时间120分钟。
第一卷第一部分听力理解（共两节，满分30分）第一节（共5小题；每小题1.5分，满分7.5分）听下面5段对话。
每段对话后有一个小题，从题中所给的A、B、C三个选项中选出最佳选项，并标在试卷的相应位置。
听完每段对话后，你都有10秒钟的时间来回答有关小题和阅读下一小题。
每段对话仅读一遍。
1. Why does the man envy（嫉妒）the woman?A. She does well in cooking.B. She often eats in the restaurant.C. She is highly successful in business.2. Where does the conversation probably take place?A. At a school yard.B. At a museum.C. At an aquarium（水簇馆）.3. How did the man go to work six months ago?A. On foot.B. By bus.C. By car.4. What does the man suggest the woman do?A. Take some medicine.B. Drink more water.C. Go on a diet.5. What can we learn from the conversation?A. T he speakers don’t know each other.B. The man slipped（滑倒）on the road.C. The woman is hurt.第二节（共15小题；每小题1.5分，满分22.5分）听下面5段对话或独白。
2010-2011学年第一学期
注：本学期上课时间：自2010年8月30日(新生自9月13日)至2010年12月31日（共18周）
复习考试时间：2011年1月3日至2011年1月14日（共2周）
网选
80
孙小春
带电脑的多媒体
3
现代科学技术革命与马克思主义(2)
10284X002
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2
数学、化学、天文、大气、材料、计算机
180
蔡仲
逸夫馆
5
6
7
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二
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五
1
23Biblioteka 45博士生英语听力（3）
现代科学技术革命与马克思主义理论（2）
6
7
博士生学术交流英语（3）
8
9
10
注：博士生学术交流英语单周教室上课，双周网络课堂
2010-2011学年第一学期
天文系天文专业博士生
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网上
讲课
1
博士生学术交流英语（3）
10284X003
4
2
2
地科、生物、模动所、医学、天文、建研所
200
从丛、王文宇
带电脑的多媒体
2
博士生英语听力（3）
10284X003
4
2
2
生物专业英语周延清课后答案
生物专业英语周延清课后答案1、She’s _______ with her present _______ job. [单选题] *A. boring; boringB. bored; boredC. boring; boredD. bored; boring(正确答案)2、How can I _______ the nearest supermarket? [单选题] *A. get offB. get upC. get to(正确答案)D. get on3、_____ Lucy _____ Lily has joined the swimming club because they have no time. [单选题] *A. Not only; but alsoB. Neither; nor(正确答案)C. Either; orD. Both; and4、It’s reported that there are more than 300?_______ smokers in China. [单选题] *A. million(正确答案)B. millionsC. million ofD. millions of5、One effective（）of learning a foreign language is to study the language in its cultural context. [单选题] *A. approach(正确答案)B. wayC. mannerD. road6、I tell my mother not ______ me.（）[单选题] *A. worry aboutB. to worry about(正确答案)C. worry withD. to worry with7、My mother and my aunt are both _______. They work in a big supermarket. [单选题] *A. actressesB. doctorsC. salesmenD. saleswomen(正确答案)8、The street was named _____ George Washington who led the American war for independence. [单选题] *A. fromB. withC. asD. after(正确答案)9、22．Will there ________ any schools in the future? [单选题] *A．isB．areC．amD．be(正确答案)10、( )He gave us____ on how to keep fit. [单选题] *A. some advicesB. some advice(正确答案)C. an adviceD. a advice11、93．Welcome ________ our school! [单选题] *A．to(正确答案)B．inC．atD．/12、The beautiful radio _______ me 30 dollars. [单选题] *A. spentB. paidC. cost(正确答案)D. took13、Actually, we don't know whether this news comes from a reliable（）or not. [单选题] *A. source(正确答案)B. originC. basisD. base14、The storybook is very ______. I’m very ______ in reading it. （）[单选题] *A. interesting; interested(正确答案)B. interested; interestingC. interested; interestedD. interesting; interesting15、What did you _______ at the meeting yesterday? [单选题] *A. speakB. tellC. say(正确答案)D. talk16、We _______ play basketball after school. [单选题] *A. were used toB. used to(正确答案)C. use toD. are used to17、My father always gets up early. He’s never late _______ work. [单选题] *A. toB. for(正确答案)C. onD. at18、This kind of work _______ skills and speed. [单选题] *A. looks forB. waits forC. calls for(正确答案)D. cares for19、It is reported（）three people were badly injured in the traffic accident. [单选题] *A. whichB. that(正确答案)C.whileD.what20、81．Some birds are flying ________ the lake. What a beautiful picture! [单选题] * A．forB．underC．inD．above(正确答案)21、The paper gives a detailed（）of how to create human embryos (胚胎)by cloning. [单选题] *A. intentionB. description(正确答案)C. affectionD. effort22、The hall in our school is _____ to hold 500 people. [单选题] *A. big enough(正确答案)B. enough bigC. very smallD. very big23、_______ a busy afternoon! [单选题] *A. HowB. What(正确答案)C. WhichD. Wish24、It seems slow for children to become _____ ,while adults often feel time flies. [单选题] *A. growns-upsB. growns-upC. grown upsD. grown-ups(正确答案)25、“I think you are wonderful,”she said, “You are so patient with your little George.”[单选题] *A. 耐心(正确答案)B. 细心C. 关心D. 偏心26、The carbon we produce when we breathe is much less than（）produced by a car. [单选题] *A. oneB. itC. that(正确答案)D. those27、Boys and girls, please _______ your favorite book here and show it to us next class. [单选题] *A. bring(正确答案)B. sellC. buyD. take28、--Why are you late for school today?--I’m sorry. I didn’t catch the early bus and I had to _______ the next one. [单选题] *A. wait for(正确答案)B. ask forC. care forD. stand for29、1．I saw ________ action film with my friend yesterday, and ________ film was amazing. [单选题] *A．a...aB．a...theC．an...the(正确答案)D．an...a30、You are getting too old for football.You had better _____tennis instead. [单选题] *A.take up(正确答案)B.take inC.take forD.take over。
2011年高考英语阅读理解分类汇编之科普知识类
2011 高考英语阅读理解分类汇编之科普知识类1.（2011 ·陕西卷） DEver since they were first put on the market in the early 1990s, gentically mondified (GM,转基因 ) foods have been increasingly developed and marketed in many countries in theword,mainly on the basis of their promise to end the worldwide food crisis. But can GMtechnology solve world hunger problems? Even if it would ,is it the best solutiorr?Despite what it promiises,GM technology actually has not increased the productionpotential of any corp. In factStudies show that the most crown GM croo.GM soybeans, has suffered reduced productivity. For instance, a report than analysed nearlytwo decades of research on mojor GM food crops shows that GM engineering has failed tosignificantly increase US crop production.Something else, however, has been on the rise, While GM seeds are expensive, GM panics tellfarmers that they will make good profits by saving money on pesticides （杀虫剂）. On the contrary,US government data show that GM crops in the US have produced an overall increase in pesticideuse pared to traditional crops.promise“Thewas that you could use less chemicals and boostproduction. But nether is true,” said Bill Christison, President of the US National Farm Coalition.At the same time, the authors of the book World Hunger: Twelve Myths argue that thereactually is more than enough food in the world and that the hunger crisis is not caused by production,but by problems in food distribution and politics. These indeed deserve our effortsand money. Meanwhile, the rise in food prices results from the increased use of crops for fuelrather than food, according to a 2008 World Bank report.As a matter of fact ,scientists see better ways to feed the world. Another World Bank reportconcluded that GM crops have little to offer to the challenges of worldwide poverty and hunger,because better ways out are available, among which“ green”farming is supposed to be the first choice.57.The author develops the second paragraph mainly.【 C】A. by classificationB. by parisonC. by exampleD. by process58.What does the underlined word“ boost ” in the third paragraph probably【D 】mean?A. Control.B. EvaluateC. Obtain.D. Increase.59.GM panies promise farmers that they will benefit from ______________.【 B】A. practicing“ green ” farmingB. use of less chemicalsC. fair distribution of their cropsD. using more crops for fuel60.Which of the following best describes the attitude of the author towards GM technology?【C】A. OptimisticB. DefensiveC. DisapprovingD. Casual2.（2011 ·重庆卷） CGetting rid of dirt, in the opinion of most people, is a good thing. However, there is nothing fixed about attitudes to dirt.In the early 16th century, people thought that dirt on the skin was a means to block out disease, as medical opinion had it that washing off dirt with hot water could open up the skin andlet ills in. A particular danger was thought to lie in public baths. By 1538, the French king hadclosed the bath houses in his kingdom. So did the king of England in 1546. Thus began a long time when the rich and the poor in Europe lived with dirt in a friendly way. Henry IV, King of France, was famously dirty. Upon learning that a nobleman had taken a bath, the king ordered that, toavoid the attack of disease, the nobleman should not go out.Though the belief in the merit of dirt was long-lived, dirt has no longer been regarded as athnice neighbor ever since the 18 century. Scientifically speaking, cleaning away dirt is good to health. Clean water supply and hand washing are practical means of preventing disease. Yet, itseems that standards of cleanliness have moved beyond science since World War Ⅱ . Advertisements repeatedly sell the idea: clothes need to be whiter than white, cloths ever softer, surfaces to shine. Has the hate for dirt, however, gone too far?Attitudes to dirt still differ hugely nowadays. Many first-time parents nervously try to warntheir children off touching dirt, which might be responsible for the spread of disease.On the contrary, Mary Ruebush, an American immunologist(免疫学家)，encourages children to play in the dirt to build up a strong immune system. And the latter position is gaining some ground.th64. The kings of France and England in the 16 century closed bath houses because.A. they lived healthily in a dirty environment.B. they thought bath houses were too dirty to stay inC. they believed disease could be spread in public bathsD. they considered bathing as the cause of skin disease65.Which of the following best describes Henry IV’ s attitude to bathing?A. Afraid.B. Curious.C. Approving.D. Uninterested.66.How does the passage mainly develop?A.By providing examples.B.By making parisons.C.By following the order of time.D.By following the order of importance.67.What is the author’ s purpose in writing the passage?A.To stress the role of dirt.B.To introduce the history of dirt.C.To call attention to the danger of dirt.D.To present the change of views on dirt.【答案】 CA CD3.（2011 ·湖南卷） CA recent study of ancient and modern elephants has e up with the unexpected conclusion that the African elephant is divided into two distinct (不一样的) speciesThe discovery was made by researchers at York and Harvard universities when they were examining the genetic relationship between the ancient woolly mammoth and mastodon to modern elephants —the Asian elephant, African forest elephant and African savanna elephant Once they obtained DNA sequences (序列 ) from two fossils ( 化石 ) ， mammoths and mastodons the team pared them with DNA from modern elephants. They found to their amazement that modern forest and savanna elephants are as distinct from each other as Asian elephants and mammoths.The scientists used detailed genetic analysis to prove that the African savanna elephants and the African forest elephants have been distinct species for several million years. The divergenceof the two species took place around the time of the divergence of Asian elephants and woollymammoths. This result amazed all the scientists.There has long been debate in the scientific munity that the two might be separate speciesbut this is the most convincing scientific evidence so far that they are indeed different species.Previously, many naturalists believed that African savanna elephants and African forest elephants were two populations of the same species despite the elephants ’significant size differences. The savanna elephant has an average shoulder height of 3.5metres while the forest elephant has an average shoulder height of 2.5metres. The savanna elephant weighs betweensix and seven tons, roughly double the weight of the forest elephant. But the fact that they look so different does not necessarily mean they are different species. However, the proof lay in the analysis of the DNA.Alfred Roca, assistant professor in the department of Animal Sciences at the University ofMinois, said, “We now have to treat the forest and savanna elephants as two different units for conservation purpose. Since 1950 all African elephants have been conserved as one species. Now that we know the forest and savanna elephants are two very distinct animals, the forest elephant should bee a bigger priority ( 优先 )for conservation purpose . ”66.One of the fossils studied by the researchers is that of ________.A. the Asian elephantB. the forest elephantC. the savanna elephantD. the mastodon elephant67.The underlined word“ divergenceinparagraph” 4means“ ________ ”A. evolutionB. exhibitionC. separationD. examination68.The researcher ’ s conclusion was based on a study of theAfrican elepha nt ’ s ____________A. DNAB. heightC. weightD. population69.What were Alfred Roca ’s words mainly about?A.The conversation of African elephants.B.The purpose of studying African elephantsC.The way to divide African elephants into two unitsD.The reason for the distinction of African elephants70.Which of the following can be the best title for the passage?A. Naturalist ’s Belief about Elephants.C. An Unexpected Finding about ElephantsB. Amazing Experiment about Elephants D.A Long scientific Debate about ElephantsC 科普说明文：African elephant 有两个不一样的种类66. fossils 定位，找到第三段第一句，有两种fossils， mam 和 mas，选项 D67. 文中 divergence of the two species 指代前文 the Ase and the Afe have been distinct species, divergence 与 distinct 同义替代，对应选项C68. conclusion, based on 定位，找到倒数第二段最后一句lay in 与 based on 同义替代，答案： A69.AR 定位，找到倒数第一段，从 AR 的话中，第一句 for conservation purpose, 最后一句for conservation purpose 确立 A70.文章首句点明全文要旨，答案：C4.（2011 ·江西卷） DWhy should mankind explore space? Why should money, time and effort be spent exploring and researching something with so few apparent benefits? Why should resources be spent onspace rather than on conditions and people on Earth? These are questions that, understandably, are very often asked.Perhaps the best answer lies in our genetic makeup( 基因组成 ) as human beings. What drove our ancestors to move from the trees into the plains, and on into all possible areas and environments? The wider the spread of a species, the better its chance of survival. Perhaps thebest reason for exploring space is this genetic tendency to expand wherever possible.Nearly every successful civilization has explored, because by doing so, any dangers in surrounding areas can be identified and prepared for. Without knowledge, we may be pletely destroyed by the danger. With knowledge, we can lessen its effects.Exploration also allows minerals and other potential ( 潜伏的 ) resources to be found. Even if we have no immediate need of them, they will perhaps be useful later. Resources may be morethan physical possessions. Knowledge or techniques have been acquired through exploration. The techniques may have medical applications which can improve the length or quality of our lives. We have already benefited from other spin-offs including improvements in earthquake prediction,in satellites for weather forecasting and in munications systems. Even non-stick pans and mirrored sunglasses are by-products ( 副产品)of technological developments in the space, the chance to save ourselves might not exist.While many resources are spent on what seems a small return, the exploration of space allows creative, brave and intelligent members of our species to focus on what may serve to saveus. While space may hold many wonders and explanations of how the universe was formed orhow it works, it also holds dangers. The danger exists, but knowledge can help human being to survive. Without the ability to reach out across space, the chance to save ourselves might notexist.While Earth is the only planet known to support life, surely the adaptive ability of humans would allow us to live on other planets. It is true that the lifestyle would be different, but human life and cultures have adapted in the past and surely could in the future.71.Why does the author mention the questions in Paragraph1?A.To express his doubts.B.To pare different ideas.C.To introduce points for discussion.D.To describe the conditions on Earth.72.What is the reason for exploring space based on Paragraph2?A.Humans are nature-born to do so.B.Humans have the tendency to fight.C.Humans may find new sources of food.D.Humans don ’ t like to stay in the same place.73.The underlined word “ spin-offs ” in Paragraph 4 probably refers to______.A. survival chancesB. potential resourcesC. unexpected benefitsD. physical possessions74.What makes it possible for humans to live on other planets?A. O ur genetic makeup.B. Resources on the earth..C. The adaptive ability of humans.D. By-products in space exploration.75.Which of the statements can best sum un the passage?A. Space exploration has created many wonders.B. Space exploration provided the best value for money.C. Space exploration may help us avoid potential problems on Earth.分析：71.推理判断。
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淋巴细胞的分类
B-淋巴细胞识别可溶性抗原并发育成抗体分泌细胞（浆细胞） TH-淋巴细胞识别细胞表面抗原并分泌细胞因子，从而激活其它免疫细胞 Tc淋巴细胞识别靶细胞抗原，并溶解靶细胞 Nk细胞识别和杀伤靶细胞
活 化 补 体
补体：是存在 于正常人和动 物血清与组织 液中的一组经 活化后具有酶 活性的蛋白质
补体的生物学作用：
①以杀伤手段补充和完善抗体的功能； ②补体的酶解片段以炎症反应的方式，动 员 机体各种防御因素； ③在抗体产生前，补体先被激活，及 时起辅助防御作用。
1996, Cell, 86:973
B－细胞
T－细胞 骨髓 胸腺 几年
来源 骨髓 成熟 骨髓
寿命 几天至十几天
胞解体
细胞毒T 细胞与肿瘤细胞结合
免疫细胞攻击癌细胞
三 免疫应答分类
根据参与的免疫活性细胞的种类和功能的不 同，免疫应答分为细胞免疫和体液免疫两类。 细胞免疫：指机体在抗原刺激下，一类小淋巴 细胞（ T细胞）发生增殖、分化，进而直接攻 击靶细胞或间接地释放一些淋巴因子的免疫作 用； 体液免疫：则指机体受抗原刺激后，来源于骨 髓的一类小淋巴细胞（B细胞）进行增殖并分 化为浆细胞，由它合成抗体并释放到体液中以 发挥其免疫作用。
二、人体免疫器官和免疫细胞
Ø免疫器官与组织
中枢淋巴器官——免疫细胞发育为免疫 活性细胞的场所 骨髓（bone marrow）：包括淋巴细 胞，巨噬细胞在内各种血细胞生成场所。 胸腺（thymus）：T-淋巴细胞发生与 成熟场所。 ※腔上囊（法式囊，bursa of Fabricius)
外周淋巴器官与组织
巨噬细胞起抗原呈递细胞（APC）作用，并分泌 IL－1。
免疫应答的类型和过程示意图
辅助细胞 （成熟的TH） 辅佐 呈递抗原 抗原 + 细胞 活化的 辅助细胞 （效应性TH） 成熟的 B 细胞 成熟的 TC 效应性 TC 淋巴因子 记忆性T细胞 记忆性B细胞 浆细胞 抗体（执行体液 （Ig）免疫功 能） 效应阶段 执行细胞 免疫功能
T细胞介导的细胞免疫应答反应
细胞免疫应答反应过程
蛋白类抗原 ¼ 抗原呈递细胞 （Antigen presenting cell,APC)处理 ¼ 复合物 （MHC ＋抗原）形成 ¼ APC 表 面 信 号 ¼Tc细胞表面受体（TCR）¼Tc细胞活化 与扩增 ¼大量致敏Tc细胞和记忆T细胞 ¼Tc 细胞分泌穿孔素等杀伤靶细胞。
细胞类型
多种髓性及淋巴性细胞 T、B 淋巴细胞
可溶性因子
许多蛋白及非蛋白因子 免疫球蛋白（抗体）
Ø抗原（antigen）及其性质
抗原是一类能诱导免疫系统发生免 疫应答反应（免疫原性）， 并能与免疫应答产 物（抗体或效应 细胞）发生特异性结合（反应原性）的 非己异物。
抗原的性质和类型
Ù 抗原性质：蛋白质或多糖类等大分子物质； Ù抗原的分类：外源性和内源性 外源性抗原如细菌、病毒、花粉、各 类毒素以及小型动植物； 内源性抗原为非己异物或构象发生改 变的自身成分，如变性的IgG 重链等。
体液免疫与细胞免疫
免疫应答反应由三个时相组成： 抗原识别、淋巴细胞的激活和效应期
细胞免疫的应答反应
主要组织相容性复合物
（major histocompatibility complex,MHC）： 是决定自身免疫耐受性的一组特异的糖蛋白抗原分子，它普 遍存在于机体有核细胞表面。除同卵双生外，不同个体具有不同 的MHC。 胚胎时期淋巴细胞成熟时，那些带有能和自身细胞MHC结合 的受体的淋巴细胞全部凋亡，剩下的淋巴细胞不能识别自身的 MHC，因此双方相安无事，即免疫自身耐受性。 MHCⅠ——Tc细胞识别与MHCⅠ（几乎全部身体细胞） 结合的抗原复合物。 MHCⅡ——TH细胞识别与MHCⅡ（巨噬细胞和B细胞） 结合的抗原复合物。
第九章 生物体的防卫系统 —免疫系统
一、非特异性免疫和特异性免疫 二、人体免疫器官和免疫细胞 三、细胞免疫和体液免疫 四、免疫学的应用
人口增长一直很慢，直到工业革命(18世纪)后剧烈增长。13481400年欧洲2500万人死于鼠疫.1918-1919年2000-4000万人死于流感.
传染病再度威胁人类
主动免疫需经抗原刺激（天然感染或人工接种），促 使机体产生免疫反应，既具特异性又有记忆性。 被动免疫不依靠自身特异性免疫反应而产生免疫性， 而通过转输外源抗体而获得免疫性（初乳、免疫球蛋白） ，具有特异性但不具有记忆性。
免疫反应的类型
固有免疫
物理屏障
皮肤, 肠绒毛, 肺、气管纤毛等 无
获得性免疫
血细胞的发生
CFC: colony-forming cells
参与固有免疫反应的细胞
1）单核巨噬细胞系统： 血液－单核细胞 肝脏－枯否细胞（kupffer cell） 结缔组织－组织细胞 骨组织－破骨细胞（osteoclast ） 神经系统－小胶质细胞（ microglia） 脾脏、淋巴结－巨噬细胞 肺－肺巨噬细胞或尘细胞（dust cell） 功能：吞噬并杀死病菌，引发炎症反应。 2）嗜中性粒细胞（ Neutrophils ）：吞噬并杀死病菌 3）嗜曙红细胞（ Eosinophils ）：杀死蠕虫、寄生虫 4）NK细胞（ Natural killer cells ）：杀死被感染细胞，真菌和寄生虫， ……
免疫性（immunity)：通常指机体对感染性疾病的抗性。
非特异性免疫
非特异性免疫是通过遗传巩固下来的先天 性免疫,对抗原的识别和作用无特异性，它构 成机体防卫的第一道防线。 如人体表皮屏障作用 ，体液的杀伤作用，生理因素（体温），炎症反 应的吞噬作用等。
固有免疫系统承担抗感染的第一道防线
上皮组织屏障 效应细胞 体液：补体系统 等
抗体多样性的基因基础
编码 H 链可变区的基因，有四种:
V 基因 有 400 种拷贝 J 基因 有 5 种拷贝 D 基因 有10 种拷贝 C 基因 有 8 种拷贝 这样，H 链可变区的编码基因可能有的组合 方式： 400×5×10×8＝1.6×105 种
L 和 H 合在一起，可能出现的组合方式： 4×103×1.6×105＝6.4×108种 再加上个体可能发生的突变，各种组合总 数可达： 109－1010种 这样天文数字的可能的抗体结构，足以应 付各种抗原结构。
四、免疫学的应用
Ø人工免疫和生物制品
通过注射、口服等方法使人体摄入抗原类 或抗体类物质，使人体增强对外来入侵的免疫 能力，称为人工免疫。 已成功地用于预防人与动物的多种传染 性疾病如：天花，小儿麻痹，狂犬病等，但受 阻于艾滋病。
人工被动免疫生物制品——向人体提
供特异的或非特异免疫能力的制品。 注射含抗体成份的抗血清， 如：蛇 毒抗血清，狂犬病毒抗血清等。 人工主动免疫生物制品——促使人体 产生特异免疫能力 注射抗原，使人体“主动地”产生特异抗体。
淋巴的特异性是先天存在的，而不是 由抗原“教育”产生的；不是“量体裁衣”而是 购买“成品衣”。 实验证据
免 疫 细 胞 活 化 后 一 部 分 变 成 记 忆 细 胞
免疫记忆与二次免疫反应
记忆细胞与二次免疫反应 克隆选择学说
淋巴的特异性是先天存在的，而不是 由抗原“教育”产生的；不是“量体裁衣”而是 购买“成品衣”。 实验证据
人工被动免疫
Ø免疫技术用于疾病治疗
一些抗血清已用于狂犬病、乙肝、破 伤风的预防和治疗。 器官移植要求免疫抑制 环胞菌素作为良好的免疫抑制剂，已广 泛用于器官移植。
Ø免疫技术用作研究手段
亲和层析： 利用 抗原 / 抗体专一性结合原理，从各 种杂蛋白中分离目的蛋白。 酶联免疫吸附法（ELISA）： 专一性检测微量的蛋白质（10－9克）， 专一性强，灵敏度高。 免疫荧光 细胞定位
感应阶段 活化阶段
增殖和分化阶段
浆细胞产生抗体
抗体分子 抗体的作用： （1）中和反应、聚集反应、沉淀反应 （2）补体反应 补体是血清中一组球蛋白（约20多种蛋白 组成的多酶体系）,参加非特异和特异性免疫。
抗体分子结构与功能位点
中和反应
（中和抗体）
聚集反应
沉淀反应
记忆细胞与二次免疫反应 克隆选择学说
体液免疫
ØB-淋巴细胞介导的体液免疫
B-淋巴细胞在抗原刺激下分化成浆细胞 和记忆细胞
抗原呈递细胞（APC）和TH细胞参与B 细胞活化
B — 细胞
浆细胞
浆细胞含大量内质网， 产生抗体
B-淋巴细胞介导的体 液免疫反应
抗原---巨噬细胞---T细胞---B细胞结合物 B细胞
进入 细胞免疫
启动 体液免疫
参与获得性免疫的细胞
单核-巨噬细胞
单核细胞（血液中）和巨噬细胞（组织中） 巨噬细胞的主要功能： 吞噬功能；抗原呈递作用；分泌免疫活性 因子；免疫调节作用。
淋巴细胞：
T-淋巴细胞（thymus-dependent lymphocyte） B-淋巴细胞（B-lymphocyte） 自然杀伤细胞（Natural killer cell,NK- 细胞）
为什么果蝇、苍蝇、蚊子等能在 肮脏的环境中生活而不被感染？
长满烟曲霉菌菌丝的果蝇－Toll通路突变体
固有免疫：TLR依赖性与TLR非依赖性
(Toll-like Receptor TLR)
特异性免疫
特异性免疫又称获得性免疫，特异性免疫 需要细胞与抗原接触、刺激而产生对抗原识别 具有特异性的免疫反应。 根据特异性免疫获得的方式，可分为主动 免疫和被动免疫。
细胞免疫
Ø T-淋巴细胞介导的细胞免疫
T-淋巴细胞的功能亚群 细胞毒T细胞（T cytotoxic Cell,Tc Cell）： 攻 击杀伤表达特异抗原的靶细胞。 辅助性T细胞（T helper Cell,TH Cell）：通过分 泌ILⅡ辅 助T细胞及B细胞的作用。 调节性T细胞（T regulatory Cell, TrCell）：抑 制B-淋巴细胞 和其它T-淋巴细胞的活动。