烟草过氧化物酶Ⅰ的分离纯化及部分光谱特性研究

烟草过氧化物酶同工酶Ⅰ (TOPⅠ )的分离纯化过程 ,主要包括匀浆、超声破碎、过滤、(NH4) 2 SO4分级沉淀、DE 5 2纤维素阴离子交换层析、SephadexG 75凝胶层析、DEAE SephadexA 5 0阴离子交换层析 .经纯化的TOPⅠ ,纯化酶的比活力为 482 6U/mg ,在SDS PAGE上显示出一条蛋白带 ,分子量在 2 1 0 0 0左右 ,基质辅助激光解吸电离飞行时间质谱 (MALDI$CTOF MS)测得TOPⅠ分子量为 2 1 888.5 ,等电点pI为 3.5 ;光谱学分析揭示 ,在 40 2nm处有一典型的Soret带 ,在 498nm和 636nm处有特征吸收峰 ,表明TOPⅠ为一含血红素的酸性蛋白酶 .酸度对TOPI的在紫外可见区的特征吸收峰及荧光光谱均产生一定的影响 ,反映了TOPⅠ分子独特的光谱学特性     

柴油无污染脱酸精制工艺研究

采用三组分溶剂对胜利柴油馏分进行了溶剂脱酸精制研究，考察了精制过程的最佳工艺条件．在剂油比为０．２５～０．３∶１、常压、温度为３０～５０℃的条件下，可将酸度小于１２０ｍｇＫＯＨ／１００ｍＬ的柴油，降至５ｍｇＫＯＨ／１００ｍＬ以下，达到优等品标准，且不影响馏分组成和闪点．萃取液在蒸发前可直接使用３～４次再去蒸发．直接回收得到的环烷酸酸值达１９０ｍｇＫＯＨ／ｇ左右，纯度达９０％以上     

高速弧齿锥齿轮动频计算

建立了旋转轮盘动力学模型，提出了基于刚度矩阵的离心刚度矩阵修正了模式下的动频求解有限元法，实现了弧齿锥齿传频的数值求解，数值计算与实测值基本一致且由算例得出结论，旋转效应对低阶模态，节径型振型影响较大，本算法对旋转轮盘类的动频计算具有通用性。     

Antioxidant survey to assess antagonism to redox stress using a prokaryotic and an eukaryotic system

Using a prokaryote (Escherichia coli) and a metazoa-resembling eukaryote (Ochromonas danica), we surveyed antioxidants which might overcome redox stress imposed by menadione sodium bisulphite (MD) and buthionine sulphoximine (BSO). BSO oxidant stress was evident only inO. danica; MD oxidant stress was evident in both organisms. Glutathione, its precursors, e.g. cysteine, homocysteine, and 2-oxo-4-thiazolidine carboxylic acid, and red blood cells, emerged as prime antioxidants for relieving BSO and MD oxidant stress. BSO and MD oxidant activity and antioxidant-annulling effect inO. danica were judged comparable to those found in animal cells whereas the resultsE. coli were not entirely equivalent. TheO. danica system emerged as a practical, rapid, and useful system for pinpointing oxidant stressors and antioxidants, and shows promise for studies with mammalian systems.     

(−)-Epigallocatechin gallate,a polyphenolic tea antioxidant,inhibits peroxynitritemediated formation of 8-oxodeoxyguanosine and 3-nitrotyrosine

Reaction with peroxynitrite at pH 7.4 and 37°C was found to increase the 8-oxodeoxyguanosine levels in calf thymus DNA 35-38-fold. This oxidation of deoxyguanosine, as well as the peroxynitrite-mediated nitration of tyrosine to 3-nitrotyrosine, was significantly inhibited by ascorbic acid, glutathione and (–)-epigallocatechin gallate, a polyphenolic antioxidant present in tea. For 50% inhibition of the oxidation of deoxyguanosine to 8-oxodeoxyguanosine, 1.1, 7.6 of 0.25 mM ascorbate, glutathione or (–)-epigallocatechin gallate, respectively, was required. For 50% inhibition of tyrosine nitration, the respective concentrations were 1.4, 4.6 or 0.11 mM. Thus, (–)-epigallocatechin gallate is a significantly better inhibitor of both reactions than either ascorbate or glutathione. Reaction of (–)-epigallocatechin gallate with peroxynitrite alone resulted in the formation of a number of products. Ultraviolet spectra of two of these suggest that the tea polyphenol and/or its oxidation products are nitrated by peroxynitrite.     

工业化初期墨西哥地方市政府决策之经济人类学研究

向城市贫困人口提供廉价的生活物资和基本服务是发展中国家面临的一个主要问题,尤其是在工业化的早期。从经济角度来讲,向这一群体提供服务是至关重要的,因为大部分的劳动力来自于这一群体,而劳动力是国家工业化的一个要素。从历史角度来看,向这一群体提供服务属于地方市政府的职责。因此,通过对地方政府决定的研究,可以找到与提供生活必需品政策相关的问题的最佳答案。工业化发展初期的墨西哥,是研究此类动态变化的理想之地。     

浅议中小企业的财务管理

财务管理在企业经营管理决策中起着重要的作用，分析了目前中小企业财务管理中存在的问题，从投资模式、管理控制和人员素质等3方面提出了解决这些问题的对策。     

家庭装潢中水管的选择

在室内装潢方面，人们较注重室内布局和装饰，而对给水管道则极少关注．应引起足够的重视。在建筑给水系统中由新型塑料管材替代金属管材已成为趋势。所以，室内给水管应选用新型塑料管材，并且应根据新型塑料管材的特点进行施工。确保给水系统的安装质量。