The role of glutathione in dopaminergic neuronal survival

An increased production of reactive oxygen species is thought to be critical to the pathogenesis of Parkinson's disease. At autopsy, patients with either presymptomatic or symptomatic Parkinson's disease have a decreased level of glutathione in the substantia nigra pars compacta. This change represents the earliest index of oxidative stress in Parkinson's disease discovered to this point. This study compares the sensitivity of dopaminergic and nondopaminergic neurons in dissociated mesencephalic cultures to the depletion of glutathione. We have found that dopaminergic neurons are more resistant to the toxicity of glutathione depletion than nondopaminergic neurons. The possibility that dopaminergic neurons have a higher baseline glutathione level than nondopaminergic neurons is suggested by measurements of levels of cellular glutathione in a parallel system of immortalized embryonic dopaminergic and nondopaminergic cell lines. We also examined the role of glutathione in 1-methyl-4-phenylpyridinium toxicity. Decreasing the glutathione level of dopaminergic neurons potentiates their susceptibility to 1-methyl-4-phenylpyridinium toxicity, although 1-methyl-4-phenylpyridinium does not deplete glutathione from primary mesencephalic cultures. Our data suggest that although a decreased glutathione content is not likely to be the sole cause of dopaminergic neuronal loss in Parkinson's disease, decreased glutathione content may act in conjunction with other factors such as 1-methyl-4-phenylpyridinium to cause the selective death of dopaminergic neurons.     

端羟基聚二甲基硅氧烯改性环氧树脂

用羟基封端的聚二甲基硅氧烷改性环氧树脂，得到具有两相结构的改性树脂，其耐热性明显提高．环氧树脂／有机硅（20／80）共混物涂层有很低的表面能，主要的机械性能则变化不大，可作为一种疏水性防护徐层．     

浅谈托辊的开发与实践

本钢１７００连轧机应用的托辊原由外企业制作，为了减少公司资金外流，公司技术人员和工人结合现有的生产条件，先后攻克了辊身铸造和加工，托辊装配等工艺方面的难关，研制成功了合格的产品，年创经济效益８０万元。     

Wave propagation in two-phase flow of magnetic fluid under a nonuniform magnetic field

The effect of nonuniform magnetic field on the linear and nonlinear wave propagation phenomena in two-phase pipe flow of magnetic fluid is investigated theoretically to realize the effective energy conversion system using boiling two-phase flow of magnetic fluid. Firstly, the governing equations of two-phase flow based on the unsteady thermal nonequilibrium two-fluid model are presented and the linear void wave propagation phenomena in boiling two-phase flow are numerically analyzed by using the finite volume method. Next, the nonlinear pressure wave propagation in gas-liquid two-phase flow is numerically analyzed by using the finite different method. According to these theoretical studies on the wave propagation phenomena in two-phase flow of magnetic fluid, it seems to be a reasonable proposal that the precise control of the wave propagation in two-phase flow is possible by effective use of the magnetic force.     

Digital Connectivity and Extended Well-Composed Sets for Gray Images

In this paper, we propose a new definition of digital connectivity for gray images on a 2D space for arbitrary grid systems. We extend a digital version of the Jordan curve theorem and its converse proved earlier by Rosenfeld for the rectangular grid system. We also extend in two directions the concept of well-composed sets introduced by Lateckiet al.(1995,Comput. Vision Image Understanding61,70–83). First, we extend the definition of well-composed sets from the quadratic grid system to an arbitrary grid system. Then, by using the concept of parameter-dependent connected components introduced by us in a previous work, we allow the pixels in a connected component of a well-composed set to have different gray values so that the connectivity of connected components accommodates a wider meaning.     

Role of hepatic resection in surgery for bilateral intrahepatic stones

The effect of phenylephrine-induced reflex parasympathetic stimulation on QT interval and its dispersion was studied in 16 healthy subjects with a history of paroxysmal supraventricular tachycardia, both during sinus rhythm and during atrial pacing. Results demonstrate that rapid reflex parasympathetic stimulation does not influence QT interval duration or QT dispersion, and also emphasize the inappropriateness of Bazett's formula, the need for comparison of QT intervals during identical heart rates, and the importance of analyzing all 12 leads of a standard electrocardiogram when assessing the effects of various interventions on the QT interval.     

水力喷砂割缝增产增注技术的作用原理及展望

本文对从俄罗斯引进的水力喷砂割缝技术的发展过程、工作原理及该技术在大庆油田的试验情况做了详细的阐述。并对它的改进及其将来的推广与发展前景做了展望。     

鲁布革水电厂计算机监控系统的更新改造

鲁布革水电厂原Ｒ３０计算机监控系统更新改造过程中，重点研究了与原西门子ＲＴＵ的数据交换，机组功率调节和线路定功率调节的实现有关问题，在对３号机组计算机监控系统改造试验的基础上，成功地实现了计算机监控系统的整体改造，改造后采用的国产ＮＡＲＩＳＳＪ－３０００计算机监控系统实用可靠，功能完善，配置灵活，具有国际，国内领先水平。     

认真总结经验继续做好大坝安全定检工作

我国电力系统的水电站大坝，大多数为高坝大库，确保这些大坝的安全，事关国民经济的发展和社会稳定的大局。因此，加强水电站大坝安全管理工作，是摆在各级电力主管部门面前的一项重大社会责任。１９８５年大坝安全监察中心（以下简称“大坝中心”）成立后，依法行使大坝安全监察职能，在国家电力主管部门的直接领导和各大坝安全责任单位的支持下，做了大量开创性工作。水电站大坝安全定期检查就是其中的一项重要内容。首轮定检从１９８７年古田溪一级开始试点到１９９８年底为止，已圆满完成９６座水电站大坝的定检工作。通过首轮定检，对…     

多传感器目标识别的图像数据融合技术研究

军事和空间技术的要求促进了微光技术的发展。微光图像实时处理技术是夜技术今后发展的重要方向，本文针对微光图像与脉冲激光测距仪的数据信息实时融合与显示的方法及其实现进行了研究。给出了系统框图及工作原理，为实现探测识别、跟踪的实时性、智能化和微型化，从而为研制新一代战术侦察与火控系统提供了具体有效的技术基础。