Quantal transmitter secretion from myocytes loaded with acetylcholine.

It is well known that transmitter secretion requires specialized secretory organelles, the synaptic vesicles, for the packaging, storage and exocytotic release of the transmitter. Here we report that when acetylcholine (ACh) is loaded into an isolated Xenopus myocyte, there is spontaneous quantal release of ACh from the myocyte which results in activation of its own surface ACh channels and the appearance of membrane currents resembling miniature endplate currents. This myocyte secretion probably reflects Ca(2+)-regulated exocytosis of ACh-filled cytoplasmic compartments. Furthermore, step depolarization of the myocyte membrane triggers evoked ACh release from the myocyte with a weak excitation-secretion coupling. These findings suggest that quantal transmitter secretion does not require secretory pathways unique to neurons and that the essence of presynaptic differentiation may reside in the provision of transmitter supply and modification of the preexisting secretion pathway.     

解放CA-141型汽车最优二级维护周期研究

结合CA－141型汽车运行生产实际，在计划预防方针指导下，借助于可靠性理论、更新理论、优化理论等，建立确定汽车最优维护周期的数学模型．并具体求出CA－141型汽车的最优二级维护周期里程．本文提供方法亦可应用于其它国产和进口汽车最优维护周期的确定。     

基于SQL的报表生成系统

本文介绍的报表生成系统的取数方式可用ＳＱＬ语句，使系统具有通用性，灵活性等特点。在系统实现中采用了多窗口全屏幕方式定义报表格式及取数方式。系统用户界面友好，直观、简单易学。     

人工神经元网络及其在系统仿真中的应用

本文简要地介绍了人工神经元网络的基本概念、主要特征及其发展历史,评述了几种有代表性的神经元网络模型。在此基础上,探讨了人工神经元网络在系统仿真中可能的应用方向。     

井下导线网陀螺经纬仪定向检测与误差分析

介绍用陀螺定向检测井下导线网测理精度的一个实例，较详细地叙述了应用中考虑的问题和成果的分析。它对应用陀螺定向这一新技术有开拓性的意义     

闸河区周边重合断裂方位分布特征及其导水趋势分析

本文应用了遥感这一先进工具,在地壳表层现实资料及地球遥感影象特征基础上,发展了遥感地质灾害方面研究新理论——重合断裂方位破裂理论,来为防治水害直接提供导水断裂趋势分布特征.     

一种减小反射式0－π调相器尺寸的新方法

在微波频率低端，按常规方法研制的调相器尺寸是大的，该文采用金属化孔和改变调整元件，结果证明，在不降低性能指标的情况下，可以减小调相器的尺寸。     

二层线性规划的几何特性与最优性条件

二层系统模型是描述具有层次特性管理决策系统的有效方法, 本文讨论了一类有广泛代表性的二层线性规划模型及其几何特性, 给出了这类二层线性规划模型最优解的几种最优性条件。     

平面刚架稳定问题的一种非线性分析方法

本文构造了既体现轴压力又体现侧向位移与轴向位移耦合因素的杆单元刚度方程,借助叠代逼近法处理非线性问题,综合杆件有限元分析的简便性与非线性分析方法的严密性,对受有水平和竖直均布载荷的单层与多层刚架稳定问题进行了研究,计算结果反映了多种因素对刚架力学响应的影响,得出有益的分析结论。     

Effect of volatile anesthetics on the circular dichroism of bilirubin bound to human serum albumin

The characteristic circular dichroism of bilirubin bound to human serum albumin undergoes a remarkable sign inversion on addition of halothane, chloroform and other volatile anesthetics. This sign inversion, which is completely reversed by removal of the anesthetic, reflects a pronounced conformational change of the bound ligand; probably a complete inversion of chirality. The observation suggests that association of volatile anesthetics with proteins can markedly alter the internal topography of receptor sites and potentially influence the stereoselectivity of ligand binding.