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991.
X M Yin K Wang A Gross Y Zhao S Zinkel B Klocke K A Roth S J Korsmeyer 《Nature》1999,400(6747):886-891
The protein Bid is a participant in the pathway that leads to cell death (apoptosis), mediating the release of cytochrome c from mitochondria in response to signals from 'death' receptors known as TNFR1/Fas on the cell surface. It is a member of the proapoptotic Bcd-2 family and is activated as a result of its cleavage by caspase 8, one of a family of proteolytic cell-death proteins. To investigate the role of Bid in vivo, we have generated mice deficient for Bid. We find that when these mice are injected with an antibody directed against Fas, they nearly all survive, whereas wild-type mice die from hepatocellular apoptosis and haemorrhagic necrosis. About half of the Bid-deficient animals had no apparent liver injury and showed no evidence of activation of the effector caspases 3 and 7, although the initiator caspase 8 had been activated. Other Bid-deficient mice survived with only moderate damage: all three caspases (8 and 37) were activated but their cell nuclei were intact and no mitochondrial cytochrome c was released. We also investigated the effects of Bid deficiency in cultured cells treated with anti-Fas antibody (hepatocytes and thymocytes) or with TNFalpha. (fibroblasts). In these Bid-/- cells, mitochondrial dysfunction was delayed, cytochrome c was not released, effector caspase activity was reduced and the cleavage of apoptosis substrates was altered. This loss-of-function model indicates that Bid is a critical substrate in vivo for signalling by death-receptor agonists, which mediates a mitochondrial amplification loop that is essential for the apoptosis of selected cells. 相似文献
992.
J E Corrie B D Brandmeier R E Ferguson D R Trentham J Kendrick-Jones S C Hopkins U A van der Heide Y E Goldman C Sabido-David R E Dale S Criddle M Irving 《Nature》1999,400(6743):425-430
A new method is described for measuring motions of protein domains in their native environment on the physiological timescale. Pairs of cysteines are introduced into the domain at sites chosen from its static structure and are crosslinked by a bifunctional rhodamine. Domain orientation in a reconstituted macromolecular complex is determined by combining fluorescence polarization data from a small number of such labelled cysteine pairs. This approach bridges the gap between in vitro studies of protein structure and cellular studies of protein function and is used here to measure the tilt and twist of the myosin light-chain domain with respect to actin filaments in single muscle cells. The results reveal the structural basis for the lever-arm action of the light-chain domain of the myosin motor during force generation in muscle. 相似文献
993.
提出塑性损伤变量的定义,它由反映微空隙群的材料相对体积膨胀来表征.从理论上导出了塑性损伤变量Dp 与经典连续损伤力学中弹性损伤变量De= 1- E/E 之间的关系.根据此关系,用实验方法确定了聚合物材料HIPS在纵向拉伸过程中损伤变量的扩展 相似文献
994.
对聚合物材料HIPS进行了系统的变形-损伤试验研究.用提出的弹塑性损伤变量与关系分析了Ⅰ型裂纹端部的损伤场,给出了损伤场内非线性纵向应变分布与纵向应力分布.给出的损伤分析方法为进一步研究裂纹在损伤区内的稳定扩展奠定了新的基础 相似文献
995.
This paper studies on fabrics suitable for child patients'garment in the hospital environment in Hong Kong,China.Subjective measurement was carried out by questionnaire survey to consult medical staff on hospital requirement about fabric criteria for child patients' garment. On the other hand, objective measurement was conducted by performing laboratory tests on fabrics,which were sourced from commercial fabric market. Both measurements are evaluated according to the results on those fabric criteria in order to determine the most suitable kind of fabric for the end purpose. As a result of the comparison, it was found that T/C 1 scores the highest index. Therefore, it will be suggested for manufacturing child patients' garment to evaluate the fabric suitability to meet the wearers' requirement through hospital trial. 相似文献
996.
This paper described the physical behaviour of three types of denim cloths produced from rotor yarn, ring yarn and modified rotor yarn (prepared by adding conventional twist to rotor yarn) respectively. Experimental work showed that denim cloth produced from the modified rotor yarn has superior properties over conventional rotor yarn in terms of surface texture and appearance,tearing strength and resistance to abrasion. 相似文献
997.
998.
近年来陈银通等在[1]、[2]中引入所谓无穷阶方阵B∞×∞的概念,利用幂级数法得出了几类高阶偏微分方程Cauchy问题解析解的表达式。但所用方法较烦杂,且[2]中结果也不太简洁。 相似文献
999.
基于STEP/SDAI的有限元自动建模和后处理技术 总被引:3,自引:0,他引:3
标准数据访问接口 (SDAI)用标准的方式来实现对数据表达和交换系统 (STEP)数据的访问和操作。用早联编方式实现了标准数据访问接口 (SDAI) ,实现了几何信息的提取和模型创建。基于AP2 0 3,实现了有限元分析本体程序与多个三维CAD软件的连接。基于AP2 0 9,实现了有限元分析系统与用户后处理分析系统之间的统一连接 相似文献
1000.