具有幂中心值的交换子的零化子

讨论了素环上具有幂中心值的交换子的零化子问题.运用Kharchenko定理和本原环的稠密定理,推广了Lie和Lin在1996年提出的重要结果,并且获得了几个相关的推论.     

环及Near-环中的微商

本文首先考虑了near-环中的一个交换性定理,然后利用Leibniz公式讨论了根在微商下的不变性及幂零、诣零微商,最后作为特例,给出在结合环中有关的几个新结果。     

Cohen－Macaulay环的推广

推广了Ｃｏｈｅｎ─Ｍａｃａｕｌａｖ环的概念，即对任何非负整数ｋ，考虑所谓的ｋ－Ｃｏｈｅｎ─Ｍａｃａｕｌａｖ环，并证明它的一些性质，比如纯粹性定理的推广。作为ｋ＝０的情形，得到通常的Ｃｏｈｅｎ─Ｍａｃａｕｌａｙ环的一些重要定理。     

多输出逻辑函数的一种化简方法

多输出逻辑函数的化简，目前还没有成熟的方法．凭经验决定蕴涵项的取舍，往往不能确定方案是否最简．由于将多个输出电路作为一个整体电路看待，每个单输出函数最简单并不能保证整体方案最简单．若能找出各输出函数间的公共项，即使它不是质蕴涵项，由于公用，也可能得到最简的方案一作者提出了一种规范而又切实可行的化简方法，用此方法最终可解决多输出函数的化简问题．     

关于Г─环的强素根与强Jacobson性质

本文证明了强素根是Г－环的特殊遗传根，若Ｒ是Г─环Ｍ的右算子环且左ｄｕｏ，则Ｓ（Ｍ）＝Ｓ（Ｒ）＊＇，．强ＪａｃｏｂｓｏｎГ─环定义为其所有同态象的素根与强素根一致，建立了Г─环Ｍ、矩阵Г＿（ｎ，ｍ）─环Ｍ＿（ｍ，ｎ）及Ｍ的右算子环的强Ｊａｃｏｂｓｏｎ性质之间的关系。     

互极大的极小素理想和零化子

本文在有单位元的交换环R中,给出了R的一个元对于R的一个理想的相对零化子的概念及相对零化子的一些性质,并得到了关于环R的素理想的几个命题。最后,通过相对零化子给出了R的一些极小素理想互极大的条件。     

Formation of 4,4′-methylene-bis(2-chloroaniline)-DNA adducts in yeast expressing recombinant cytochrome P450s

N-Oxidation of 4,4-methylene-bis(2-chloroaniline) (MBOCA) may lead to formation of DNA adducts. To determine if cytochrome P450s are involved in the formation of MBOCA derived-DNA adducts, yeast strains expressing rodent P450s were exposed to MBOCA, and³²P-postlabelling of nucleotides from yeast genomic DNA was done. Chromatographic analysis on PEI cellulose showed that, upon exposure to MBOCA for 1 h, nine DNA adducts were formed in yeast expressing phenobarbital-inducible rabbit P450 2B5. With a 4-h-exposure, all adducts increased in parallel. In cell-free experiments, the incubation of MBOCA with phenobarbital-induced rat microsomal fraction followed by incubation with thymus DNA, led to the formation of more than ten DNA adducts. When yeast expressing 3-methylcholanthrene-inducible rat P450 1A1 was exposed to MBOCA, one major and two minor adducts were formed. No adducts were detected in control yeast. These results show that recombinant rabbit P450 2B5 exhibits a potential activation of MBOCA and that rat P450 1A1 has some effect. The use of yeast expressing recombinant P450s and the technique of³²P-postlabelling facilitates a simple search for chemicals with carcinogenic potential.     

Steroid hormones enhanced sister-chromatid exchange in cultured CHO cells

Summary The influence of steroid hormones on the induction of sister-chromatid exchange (SCE) in cultured CHO cells was studied. It was observed that estradiol-17 , estriol, estrone and ethynyl estradiol treatments enhanced SCE rates compared to the controls. Overall, these compounds produced a dose response effect. The importance of a detailed study on the long-term genetic effects of steroids on mammalian cells is emphasized.This work was supported by NIH-Minority Biomedical Research Support Program (MBRS), Grant No. RR 08124-11. The author is thankful for the technical assistance provided by NIH-MBRS student, Hoang Duong.