Evidence for the involvement of ATP in co-translational protein translocation

Identification of the source of energy for protein translocation across biological membranes is important in understanding the mechanism of this process. In eukaryotic cells, the tight coupling between translation and translocation and firm attachment of the secreting ribosomes to membranes, as well as theoretical calculations, have led to the suggestion that energy derived from protein synthesis is sufficient for protein translocation. On the other hand, in bacterial systems neither the attachment of ribosomes to membrane (other than nascent chains) nor tight coupling of translocation to translocation has been observed. Moreover, certain proteins can be translocated across membranes either at the time of, or after, translation. The separation of protein translocation from translation has made possible the demonstration that ATP hydrolysis is essential for post-translational protein translocation across bacterial membranes and, more recently, also across canine and yeast endoplasmic reticulum membranes. Here we report that certain ATP analogues inhibit co-translational protein translocation at concentrations that do not interfere with protein synthesis, suggesting that ATP is also required for co-translational protein translocation.     

两亲配合物Cd(HQ)_2LB膜的结构及其电致发光器件研究

制备了两亲配合物二［Ｎ一十六烷基－８－羟基－２－喹啉甲酰胺］合镉［Ｃｄ（ＨＱ）２］的ＬＢ膜材料．采用π－Ａ等温线、紫外可见吸收光谱和荧光光谱等方法研究了ＬＢ膜的结构．结果表明：ＬＢ膜分子排列是二维有序的超晶结构，Ｃｄ（ＨＱ）２分子的两个长链烷基垂直于亚相平面，两个亲水头基（８－羟基喹啉）相对于法线以一定的角度倾斜；Ｃｄ（ＨＱ）２的单分子占有面积为０．７３ｎｍ２，单层高度２．５２ｎｍ．其ＬＢ膜的高荧光性质可作为电致发光器件的发光材料，器件的驱动电压为７Ｖ，最大亮度为１２００ｃｄ／ｍ２．     

关于在一般条件下利用低功率He-Ne激光器拍摄微动态物体全息图的研究

文章根据拍摄微动态物体全息图时允许物体的最大速度和微动物体的振动特点,研完了用低功率He—Ne激光器拍摄这种物体的方法,在一般实验台上拍出了这类物体的全息图,并提出用He—Ne激光器拍摄人体全息图的可能性。     

平面连通图为哈密顿图的一个充要条件

本文利用对偶的概念，给出了平面连通图为哈密顿图的一个充要条件。 定理 平面连通图G（V≥3）为哈密顿图的充要条件是存在G的对偶图G＊＝（V＊，X＊）满足： （１） Ｖ＊ ＝Ｖ１＊：Ｖ２８，Ｖ１＊∩Ｖ２＊＝，Ｖ１＊≠，V２＊≠ （２）Ｖ１＊和Ｖ２＊的诱导子图＜Ｖ１＊＞和（Ｖ２＊）均是树。     

Analyses of nitrobenzene, benzene and aniline in environmental water samples by headspace solid phase microextraction coupled with gas chromatography-mass spectrometry

Nitrobenzene, benzene and aniline are widely used in chemical industries as solvents and reaction interme- diates. Their discharge or leakage to the environment will result in serious environmental pollution, so it is very important to propose a fast and …     

浅论国外外语教学流派与我国大学英语教学

单一教学法不符合当今我国大学英语教学实际情况。文章通过对我国大学英语教学产生重大影响的四种外语教学法-语法翻译法、听说法、认知法、和交际法-其理论依据和特点进行简要描述,指出各自的局限性和适用性。作者认为应依据国内外外语教学法研究成果,结合我国大学英语教学实际,融合各派合理成分,取优去弊,互补共存,构建适合我国大学英语教学特点的教学法。     

风力发电机组塔架的仿竹结构设计

针对风力发电机组塔架高耸结构稳定性问题,结合仿生结构设计理论,将竹子纤维束引入塔架结构,研究通过仿竹结构设计提高塔架稳定性的方法.以2 MW风力发电机组塔架为研究对象,采用层次分析法对竹子与塔架的相似度进行计算,验证生物选型的合理性.通过研究竹子纤维束特征与竹身稳定性的关系,设计出具有4根加劲肋的仿竹塔架.应用有限元数值分析方法对仿竹塔架和原型塔架的静态和动态效能进行分析,结果表明:仿竹塔架的塔顶位移和最大应力相较原型塔架分别降低了2.27%和13.48%,仿竹塔架前两阶固有频率相较原型塔架提升了1.31%和1.58%,仿竹塔架结构整体稳定性提升了1.4%.验证2 MW风力发电机组塔架仿竹设计的可行性可为后续塔架结构设计提供新的方法.     

系统可靠性分析中元件不确定性重要度

不确定性是系统可靠性分析中遇到的一个突出的问题。不确定性重要度分析就是通过计算各元件的不确定性对系统不确定性的影响程度大小,给出控制系统不确定性的最佳途径。本文介绍了国外学者已定义的几个不确定性重要度度量,指出了它们各自的不足,并提出一种新的不确定性重要度——Monte Carlo 方差重要度。它具有完美的理论性和良好的工程实际使用性。我们讨论了该重要度的性质,还编制了计算机程序,给出了一个算列。     

Pricing Strategies in a Supply Chain with Multi-Manufacturer and a Common Retailer Under Online Reviews

Online reviews play an important role in consumer purchasing behavior when shopping online, and in turn affect pricing strategies of sellers. We consider a supply chain consisting of three competitive manufacturers and an e-tailer, which sells multiple substitutable products procured from different manufacturers. Considering reviews in terms of quality information and fit information, we study the effect of online reviews on consumers’ purchasing decisions as well as pricing strategies of manufacturers and the e-retailer. Through modelling customer choice with online reviews based on neo-Hoteling model and solving Stackelberg game composed by manufacturers and e-tailer, we obtain the optimal equilibrium prices of manufacturers and the e-tailer. And we distinguish two kinds of effect from online reviews: effect of the opinion bias in product quality and effect of the match informativeness. Furthermore, compared to the case without online reviews, we find online reviews improve a manufacturer’s optimal wholesale price, profit as well as the retailer’s optimal retailing price, when the adjusted quality revealed by reviews is high; however, online reviews can improve the e-tailer’s optimal profit, only when the standard deviation of products’ quality revealed by reviews is large enough. Last, we get that the increase of competing manufacturers’ quantity would change the dominance between two kinds of effect from reviews on supply chain members.     

在综合性高校中开展灾害卫生学课程教学效果评价与分析

目的:了解综合性高校开展灾害医学教育的效果,为课程的教学改革提供科学依据。方法:利用问卷调查的方式对选修了灾害卫生学课程的医学类和非医学类学生进行调查。结果:2010—2013年选课人数分别为112、120和120人,有98.9%的同学认为该门课程值得学习,其中31.2%的人认为该门课程非常值得学习;学生对灾害卫生学教材的使用普遍反映较好,94.9%的同学认为选用的教材和参考资料很有价值,值得使用;23.9%的同学认为使用本版教材非常好;176个被调查的选课同学中,71.6%人认为老师授课有激情,教学效果非常好;73.9%的同学认为教学内容先进,信息量大;54.5%的人认为课内外容易与老师进行多种形式的交流。结论:该门课程的选课率较高,大学生已经认识到了灾害医学知识教育的的重要性和紧迫性,高校应该积极开展灾害医学的教育。