In situ observation of C60（C（COOH）2）2 interacting with living cells using fluorescence microscopy

1 Introduction In recent years, studies on biological effects of thenanoscale materials have become the cornerstone of rapidly developed nanomedical and nanobiological technologies. Moreover, studies on the bio-effects when the different kinds of nanoscal…     

中华绒螯蟹Eriocheir sinensis两个地理种群的微卫星DNA多态性分析

为了获取中华绒螯蟹群体遗传多态性的基本数据，寻找合适的遗传标记区分不同种类及不同水系的河蟹种群，采用微卫星DNA分型技术，对江苏地区两个地理种群（本地种与荷兰种）的中华绒螯蟹共计140个样本，通过DNA提取、PCR扩增、聚丙烯酰胺凝胶电泳、银染检测的方法，进行了两个微卫星基因座（Esin 67和Esin 87）的遗传多态性分析．结果表明：中华绒螯蟹本地种与荷兰种的两个微卫星基因座均有较好的多态性；在Esin 67基因座中，本地种和荷兰种绒螯蟹均有8个等位基因，两组的最高频率等位基因均为8重复序列；在Esin 87基因座中，本地种绒螯蟹有9个等位基因，荷兰种有7个等位基因，两组的最高频率等位基因均为9重复序列．同时中华绒螯蟹荷兰种这两个基因座的杂合度和多态性信息含量均高于本地种．这些结果提示了江苏本地的绒螯蟹可能受到其它地区河蟹的种质污染，基因多态性下降，因此需要加强对种质资源遗传变异的深入研究，以便采取措施对河蟹资源进行合理的管理、保护和开发利用．     

玻璃纤维/聚丙烯长丝喷气混纤纱力学性能研究

利用电镜观察玻璃纤维／聚丙烯长丝喷气混纤纱的结构，并通过对单纱热压，分析纱结中玻璃纤维的状态；在DCS500岛津试验机上测试了喷气混纤纱的性能。通过研究得到：喷气混纤纱的拉什强度和模量、纱线断裂伸长率受玻璃纤维／聚丙烯丝的混合程度、玻璃纤维在纱线中的状态、纱干表面聚丙烯纤维丝圈状态影响。     

多智能体组织中个体行为的影响因素研究--分配政策、协同作用的影响分析

分析了在不同的产出分配政策、组织协同作用水平和个体智能体偏好情况下,组织整体行为与其成员智能体行为之间的关系.通过对多智能体组织模型的构建,借助数学分析和计算机模拟,得到了关于多智能体组织规模、生产函数和自组织工作等不同假设情况下的组织行为特点和个体最优行为策略.研究结论为认识多智能体组织的行为规律及其管理制度设计提供理论基础.     

机械激活和固相反应合成Mg2Ni合金

通过机械合金化机械激活和固相反应制备了Mg2Ni合金,用XRD和EDS对合金进行了分析.实验研究表明混合粉经机械研磨激活和适当增加固相烧结反应的温度,这样可有效增加固态扩散反应能力,有利于固相反应进行,使形成Mg2Ni的量明显提高.实验结果发现,成分配比、烧结反应温度及时间均影响最终Mg2Ni的纯度,其中反应温度是影响固相反应Mg2Ni形成的重要因素,当Mg增量取0.5%,烧结温度为700 ℃,保温时间6 h时可得到组织单一和纯度较高的Mg2Ni合金相.     

On thein vitro bioassay for measuring melanophoretic activity

Résumé Les auteurs décrivent diverses modifications au test original deShizume et al. pour mesurer l'activité mélanophorétiquein vitro. Une analyse mathématique des résultats obtenus avec cet étalonnage en montre les caractéristiques satisfaisantes.

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Acknowledgments. This work was supported by research grants (No. A-2543, C₁, C₂) from the National Institute of Health (NIH) of the U.S. Public Health Service and Contract No. AF 419657)-224 with the School of Aviation Medicine, U.S. Air Force, Wright Air Development Division, Lackland Air Force Base, Texas.     

Reaction path of protein farnesyltransferase at atomic resolution

Protein farnesyltransferase (FTase) catalyses the attachment of a farnesyl lipid group to numerous essential signal transduction proteins, including members of the Ras superfamily. The farnesylation of Ras oncoproteins, which are associated with 30% of human cancers, is essential for their transforming activity. FTase inhibitors are currently in clinical trials for the treatment of cancer. Here we present a complete series of structures representing the major steps along the reaction coordinate of this enzyme. From these observations can be deduced the determinants of substrate specificity and an unusual mechanism in which product release requires binding of substrate, analogous to classically processive enzymes. A structural model for the transition state consistent with previous mechanistic studies was also constructed. The processive nature of the reaction suggests the structural basis for the successive addition of two prenyl groups to Rab proteins by the homologous enzyme geranylgeranyltransferase type-II. Finally, known FTase inhibitors seem to differ in their mechanism of inhibiting the enzyme.     

CREB regulates hepatic gluconeogenesis through the coactivator PGC-1

When mammals fast, glucose homeostasis is achieved by triggering expression of gluconeogenic genes in response to glucagon and glucocorticoids. The pathways act synergistically to induce gluconeogenesis (glucose synthesis), although the underlying mechanism has not been determined. Here we show that mice carrying a targeted disruption of the cyclic AMP (cAMP) response element binding (CREB) protein gene, or overexpressing a dominant-negative CREB inhibitor, exhibit fasting hypoglycaemia [corrected] and reduced expression of gluconeogenic enzymes. CREB was found to induce expression of the gluconeogenic programme through the nuclear receptor coactivator PGC-1, which is shown here to be a direct target for CREB regulation in vivo. Overexpression of PGC-1 in CREB-deficient mice restored glucose homeostasis and rescued expression of gluconeogenic genes. In transient assays, PGC-1 potentiated glucocorticoid induction of the gene for phosphoenolpyruvate carboxykinase (PEPCK), the rate-limiting enzyme in gluconeogenesis. PGC-1 promotes cooperativity between cyclic AMP and glucocorticoid signalling pathways during hepatic gluconeogenesis. Fasting hyperglycaemia is strongly correlated with type II diabetes, so our results suggest that the activation of PGC-1 by CREB in liver contributes importantly to the pathogenesis of this disease.     

经济的耐腐蚀泵的综合设计

本文探讨了水泵的腐蚀机理,在分析调研、试验的基础上,对经济的耐腐蚀泵的可靠性进行了深入的研究,提出了经济的耐腐蚀泵的综合设计。