pH effect of· OH radical induced oxidation of phosphoryl- methionine in aqueous solution

Conclusion The results of pulse radiolytical research on the · OH radical-induced oxidation of NDM in aqueous solution demonstrate that pH value has a great influence on the radiolytical mechanism of NDM. At low pH value, the product is mainly stabilization of the oxidizing sulfur centre in the three-electron-bonded cation radical NDM₂ ·⁺ [S]; with the increase of pH value, NDM₂ ·⁺ [S] gradually decays to become the reducing α-amino radical which was verified by the chemical method and whose yield was also calculated. Compared with Met₂ ·⁺ [S] produced by the · OH radical-induced oxidation in aqueous solution [1], the stability of NDM₂·⁺ [S] increases and the yield of α-amino radical decreases. This suggests that the introduction of phosphoryl group has a coordinating effect on the radioprotection of methionine to biological systems, and provides the essentially theoretical foundation for the thorough clarification of the reversible phosphorylation of proteins.     

用渐变间隙的矩形波导提高远红外自由电子激光器的效率

提出使用渐变间隙的矩形波导提高远红外自由电子激光器效率的新思想。在理论上用单粒子模型分析了提高效率的机制，并用数值模拟对理论作了验证。     

Fractal Medium Model for Diffusion in Dense Polymer Membranes

ＦｒａｃｔａｌＭｅｄｉｕｍＭｏｄｅｌｆｏｒＤｉｆｕｓｉｏｎｉｎＤｅｎｓｅＰｏｌｙｍｅｒＭｅｍｂｒａｎｅｓ＊ＳｈａｎｇＴｉａｎｇａｎｇ（尚天刚），ＣｈｅｎＣｕｉｘｉａｎ（陈翠仙），ＬｉＬｉｎ（李琳），ＪｉａｎｇＷｅｉｊｕｎ（蒋维钧）Ｄｅｐａｒｔｍｅｎｔ...     

漆树漆酶的催化氧化作用Ⅺ原儿茶酸酯类的漆酶酶催氧化

用分光光度法对原儿茶酸甲酯、正丁酯、正辛酯底物在不同ｐＨ条件下的离解和漆酶催化氧化反应进行了考察，测定了它们在ｐＨ＝８．０时的反应速度常数．结果表明，不为漆酶所喜爱的亲水性底物（原儿茶酸），经过适当疏水化处理，可以有效地改善其反应性和提高漆酶的催化活性．ＥＳＲ结果证明，这些底物的漆酶催化反应都经历了半醌自由基阴离子阶段；酯基的存在不能保证底物顺利地氧化成相应邻醌，用二苯乙二胺只能捕获到少量羟基化的邻醌     

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.     

分次环的群环的根

发展了Ｎａｓｔａｓｅｓｃｕ提出的分次环的群环理论，并以此为工具，研究了分次环的群环上的分次模的半单笥问题及其Ｊａｃｏｂｓｏｎ根。     

温度对正负离子表面活性剂及其复配体系表面活性的影响

本文应用张力法测定了正负离子表面活性剂及其复配体系在不同温度下的表面张力，研究了各种体系的表面性质与温度的关系，并计算了在不同温度下的标准自由能变化．对不同体系的变化规律作了讨论．     

可迁格序置换群

给出了可迁置换群是单可迁的等价条件，证明了可数自由群及其直积可以嵌入到有理数集Ｑ的格序置换群Ａ（Ｑ）中。     

人体血浆中游离脂肪酸的气相色谱测定

建立了以ＣＨ３ＯＨ－ＢＦ３甲酯化、毛细管气相色谱法测定人体血浆中游离脂肪酸的分析方法。方法简便可靠，回收率高。利用该方法测定了７例血浆中游离脂肪酸组成和含量，取得满意结果     

蕴涵环交换性的某些多项恒等式

设ｍ＞１，ｎ，ｐ，ｑ，ｒ，ｓ均为正整数，Ｒ是一个具有单位元１的环．证明了：如果Ｒ中的任意ｘ，ｙ满足且Ｒ具有Ｑ（ｍ）性质，则Ｒ是一个交换环．此外，在适当的条件下确立了Ｒ的交换性．