左旋多巴的合成与提取

左旋多巴 (L DOPA)是治疗帕金森病的有效药物。L DOPA的生产方法有化学合成、从植物中提取和微生酶物转化等 ,其中利用微生物的酪氨酸酚解酶以邻苯二酚、丙酮酸和氨为底物合成L DOPA被证明是一种最经济且最有前途的方法。应用基因工程技术构建高效菌株。左旋多巴的提取有多种方法 ,其中向反应体系中加入晶种使多巴从反应体系中析出 ,除去菌体和杂质 ,再进行重结晶可得到纯度较高的多巴是一种很好的方法。     

细胞分裂图形图像的判断及应用

细胞分裂图形图像的判断,是教学的重点,也是学习的难点.掌握一套行之有效的判断方法,将提高解题速度和正确率.     

脱落酸应答基因的表达调控及其与逆境胁迫的关系

本文对生长调节物质脱落酸应答基因的类型、结构和功能特征、表达调控的分子机理,以及近年来的热点问题：ABA在逆境胁迫反应中的作用机制,ABA应答基因与逆境胁迫的关系等作了较全面的综述。     

The Atlatl: The Physics of Function and Performance

Abstract

An examination of the physical laws behind the function and performance of the atlatl-both with and without weights-is presented. The increased distance a dart can be thrown with the atlatl is a function of the increased mechanical advantage which the atlatl provides by increasing the length of the moment arm. The location of weight on an atlatl is shown to produce a performance less than or equal to that achieved without a weight. It is proposed, although unproven, that the addition of a weight to an atlatl acts as a stabilizing device to reduce side to side oscillations and thereby providing greater control. The penetration of a projectile thrown with an atlatl is greater than that of one thrown by hand and about equal to that of an arrow shot from a bow.     

The law and neuroscience

Some of the implications for law of recent discoveries in neuroscience are considered in a new program established by the MacArthur Foundation. A group of neuroscientists, lawyers, philosophers, and jurists are examining issues in criminal law and, in particular, problems in responsibility and prediction and problems in legal decision making.