173 research outputs found
Regulation of Ubiquitination and Sumoylation of Retinoic Acid Receptor α by Retinoic Acid
全反式视黄酸(all-transretinoicacid,ATRA)是维生素A的衍生物,在细胞增殖、分化和凋亡过程中起着重要作用。ATRA主要通过视黄酸受体(retinoicacidreceptors,RARs)和视黄素X受体(retinoidXreceptors,RXRs)介导发挥功能。另外,蛋白翻译后的修饰如磷酸化(phosphorylation)、泛素化(ubiquitination)和类泛素化(sumoylation)对于调节视黄酸受体活性起到了重要的作用。本文研究发现,在胃癌细胞(BGC-823)中,ATRA上调RARαmRNA和蛋白表达水平。然而,在乳腺癌细胞(MCF-7)中,AT...All-trans retinoic acid (ATRA) is a Vitamin A-derived retinoid,which plays an important role in regulating a broad range of biological processes including cell proliferation, differentiation and apoptosis through its receptors, RARs (retinoic acid receptors) and RXRs (retinoid X receptors). In addition, posttranscriptional modifications, such as phosphorylation, ubiquitination and sumoylation, als...学位:理学硕士院系专业:生命科学学院生物学系_细胞生物学学号:20022605
Photosynthetic capacity of three common species of macroalgae and the application in coral aquarium
利用水下饱和脉冲调制叶绿素荧光仪(dIVIng-PAM)测定了珊瑚养殖水处理中3种常见大型海藻石莼(ulVA lACTuCA)、条浒苔(EnTErOMOrPHA ClATHrATA)和羽状蕨藻(CAulErPA MEXICAnA)光能转化效率(fV/fM),快速光曲线(rlC)相关参数和非光化学淬灭(nPQ)。结果表明:石莼和条浒苔的fV/fM分别为0.808±0.004和0.816±0.009,显著高于羽状蕨藻。最大相对电子传递速率rETrMAX(17.52±2.92和19.59±4.43μMOl E·M-2·S-1)、半饱和光强Ik(53.41±8.18和59.71±13.52μMOl PHOTOnS·M-2·S-1)也明显高于羽状蕨藻(rETrMAX和Ik分别为13.72±5.41μMOl E·M-2·S-1和32.67±14.06μMOl PHOTOnS·M-2·S-1),表明石莼和条浒苔有着比羽状蕨藻更高的光合能力和对强光的耐受能力,光保护能力更强;羽状蕨藻较高的rlC初始斜率α表明其在弱光下拥有更强的光捕获能力,弱光下光合效率更高;随光照的增强(0~373μMOl PHOTOnS·M-2·S-1),羽状蕨藻nPQ的增幅有限(0~0.2),最大值仅为条浒苔和石莼的38.1%和62.5%,表明这种藻类更容易受到强光的抑制。因此,在珊瑚养殖的水处理中,可以根据不同的光照选择适宜的藻种或藻种组合并根据光梯度进行布局,反之也可以根据藻种来选择合适的光源,以达到最佳的处理效率。This study investigated the difference of photosynthetic capacity in three macroalgae species( Ulva lactuca,Enteromorpha clathrata,and Caulerpa mexicana) commonly used for nutrient removal in coral aquariums.The photochemical efficiency( Fv/Fm),parameters relevant to rapid light curve( RLC) and non-photochemical quenching( NPQ) in the macroalgae were measured by underwater saturation pulse modulated chlorophyll fluorometer( Diving-PAM).The results showed that Fv/Fmwas 0.808 ± 0.004 for U.lactuca and 0.816 ± 0.009 for E.clathrata,which were higher than that for C.mexicana.Higher maximum relative electron transfer rates( rETRmax)( 17.52 ±2.92 and 19.59 ±4.43 μmol e·m- 2·s- 1) and half-starved value of light intensities( Ik)( 53.41 ±8.18 and 59.71 ±13.52 μmol photons·m- 2·s- 1) were observed in U.lactuca and E.clathrata than that in C.mexicana( 13.72 ± 5.41 μmol e·m- 2·s- 1for rETRmaxand 32.67 ± 14.06 μmol photons·m- 2·s- 1for Ik),indicating that U.lactuca and E.clathrata have stronger photosynthetic capacities,photo-protection capacities and tolerance to higher intense light than C.mexicana.A significantly lower RLC initial slope α in C.mexicana implied that this algal species has a higher photosynthetic capacity under weak light condition.With increasing the light intensity( 0- 373 μmol photons·m- 2·s- 1),however,C.mexicana had a limited increase of NPQ( 0- 0.2),the maximum of which was equivalent to 38.1% of that in U.lactuca and 62.5% of that in E.clathrata.These results indicate that the photosynthesis of E.clathrata may be more easily limited by intense light.Our study suggests that the selection of algal species for nutrient removal in a coral aquarium should be adapted to the light intensity.Single species or the combination of different species of macroalgae can be selected according to the illumination of the coral aquarium in order to maximize the efficiency of nutrient removal.国家海洋局第三海洋研究所基本科研业务项目(海三科2011033); 厦门海洋研究开发院共建项目; 海洋公益性行业科研项目(201105012)资
从信息不对称角度看境外机构投资者可能带来的负面影响
实行境外机构投资者制度是我国谨慎对外开放证券市场的重要步骤之一。但如果考虑到信息不对称的问题,则境外机构投资者可能产生的负面影响也是不容忽视的。主要是因为:首先,由于投资者与机构投资者之间、机构投资者与上市公司之间存在双重委托代理关系,结果可能导致机构投资者行为的非理性化。其次,由于新兴市场国家的金融市场还很不完善,境外机构投资者因存在着信息不对称而难于发挥其对新兴市场的积极作用。所以境外机构投资者的进入未必能促进新兴市场经济的增长和资源的有效配置;境外机构投资者的某些交易策略可能影响新兴市场国家证券市场的稳定。为此,就如何进一步完善我国的境外机构投资者制度,更好地发挥境外机构投资者对我国证券市场及经济发展的积极作用提出若干政策建议
Comparison of the preparation methods of Temozolomide-loaded nanoparticles
目的比较载替莫唑胺聚氰基丙烯酸正丁酯纳米粒(TMz-PbCA-nP)的不同制备方法,确定最佳制备工艺。方法以α-氰基丙烯酸正丁酯(bCA)为载体,分别采用乳化聚合法和界面聚合法制备TMz-PbCA-nP,加以吐温-80(T-80)进行表面修饰,并通过zETA电位仪检测纳米粒粒径和电位、透射电镜观察纳米粒形态、紫外分光光度计测定各自的包封率和载药量。结果乳化聚合法制备的TMz-PbCA-nP平均粒径(135.8±11.3)nM,表面电位(-24.8±2.2)MV,包封率(44.23±2.04)%,载药量(2.80±0.05)%;界面聚合法制得的载药纳米粒平均粒径(175.4±10.2)nM,表面电位(-18.3±3.6)MV,包封率(44.35±2.58)%,载药量(2.31±0.47)%。透射电镜下观察两种方法所制备的纳米粒大小均较为均匀,粒子间无明显聚集。结论采用乳化聚合法制备TMz-PbCA-nP效果较优于界面聚合法。【Objective】 To compare Temozolomide polybutylcyanoacrylate nanoparticles(TMZ-PBCA-NP) prepared by two different methods so as to determine the optimal process.【Methods】 TMZ-PBCA-NP was prepared by emulsion polymerization and interfacial polymerization methods separately and the surfaces of the two kinds of nanoparticles were both modified with tween-80(T-80).Zeta potential instrument was used to detect the particle size and charge and transmission electron microscopy was employed to study the particle shape.The entrapment efficiency and drug loading were determined with ultraviolet spectrophotometry.【Results】 The mean particle size,surface charge,entrapment efficiency and drug loading of the NP prepared by emulsion polymerization and interfacial polymerization methods was(135.8±11.3) nm and(175.4±10.2) nm,(-24.8±2.2) mV and(-18.3±3.6) mV,(44.23±2.04) % and(44.35±2.58) %,(2.80±0.05) % and(2.31±0.47) %,respectively.Both nanoparticles had uniform size distribution and no apparent aggregation according to transmission electron microscopy.【Conclusion】 The emulsion polymerization method is better than interfacial polymerization method in preparing TMZ-PBCA-NP.国家自然科学基金(No:81172394
SBS分子结构对其在选择性溶剂中自组装行为的影响
线形两嵌段(SB)、线形三嵌段[(SB)2]和星形四臂三嵌段[(SB)4]的苯乙烯-丁二烯嵌段共聚物(SBS)溶于选择性溶剂丁酮后的聚集自组装行为差异极大。粘度测定和透射电镜观察结果表明,在溶液中,(SB)4由其内部聚丁二烯嵌段(PBD)聚集自组装成单分子核-壳结构;(SB)2在低于转折浓度时由多个分子的PBD聚集自组装成开放式核-壳结构,在高于转折浓度时则成为稳定聚集体;而SB自组装成为宏观不溶的特大胶体微粒
创建厦门区域金融中心的构想及措施
创建厦门区域金融中心,对于充分发挥厦门在海峡西岸经济区的龙头作用,推动海峡两岸经济金融的共同发展具有重要的意义。本文探讨了建设厦门区域金融中心的必要性和可行性,提出建设厦门区域金融中心的总体目标和具体措施。厦门市“十一五”规划课题“创建厦门区域金融中心的构想及措施”成果之
The Hydraulic Cylinder with Extensive Position Controlled Piston Rod
该文介绍了一种活塞杆伸出量可测并可控的液压缸。该缸利用滚珠丝杆将活塞杆的直线位移转化为丝杆角位移的方法进行位置测量,其结果由光栅编码器输出并传送到控制中心,由控制中心控制伺服阀的阀口方向和开口大小,从而对液压缸活塞杆产生控制作用。本文对其原理进行了阐述,并对可能存在的测量误差进行了分析。This paper introduces a hydraulic cylinder that its piston rod extension can be effectively controlled,linear displacement of the piston rod can be changed into the screw angular displacement by ball screw,then the distance are outputted by grating angular displacement sensor to the control center,valve port opening direction and size are controlled by the control center and then hydraulic cylinder piston rod is controlled so.This paper describes its principles and demonstrates its feasibility
基于超级块支配图插装的软件测试工具设计与实现
通过超级块支配图来分析软件测试探针的合理插装位置,可有效地减少插装探针数量,降低代码插装对程序的影响。基于超级块支配图的代码插装原理,设计一种针对C语言的软件自动测试工具(SAT),介绍了该工具中词法语法分析器、静态分析器、代码插装器等主要功能模块的具体实现方案,同时对SAT的插装性能进行了分析
基于P2P技术的多媒体网络会议模型
本文提出了一种基于P2P技术的多媒体网络会议设计模型,该模型采用Chord协议组织节点和实现节点路由定位,将服务器的职能分布到P2P Overlay的各节点上,并根据节点的异构性将它们分为普通节点和超级节点,各节点根据自身能力各尽所能,使网络资源得到充分利用,可有效解决C/S模式下中央服务器带来的性能瓶颈问题。仿真实验表明该网络会议系统模型具有负载均衡、易于扩展和高效的资源定位等特点
Clinical analysis of perimenopausal women presenting initially with dry eye symptom
目的探讨围绝经期妇女的干眼症状与干眼病诊断的相关性。方法分析56例具有干眼症状的围绝经期妇女眼部检查的临床资料,观察主诉为干眼症状患者的干眼病确诊率及其关系。结果56例以干眼症状为主要表现的围绝经期妇女,确诊水液缺乏型干眼17例(30.4%),蒸发过强型干眼12例(21.4%),混合型干眼8例(14.3%);不能诊断干眼病的19例(33.9%),最终诊断为围绝经期综合征。结论围绝经期妇女干眼病确诊率较高(66.1%),但部分干眼症状可以只是围绝经期综合征的精神神经症状的一种表现,临床诊断干眼应慎重。
【英文摘要】 Objective Diagnosis and treatment of dry eye are important for improving living quality.Present paper was to investigate the correlation between dry eye manifestations and diagnosis of dry eye disease in perimenopausal women.MethodsThe clinical data of 56 perimenopausal women presenting initially with dry eye symptoms including ocular symptoms,slit-lamp examination,tear film break-up time,basal and reflex Schirmer test,vital staining(fluorescence and rose bangle),and meibomian gland dysfunction examination ..
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