二甲氧基甲烷在酸介质中的电氧化特性

DMM在pH<2.5时会发生水解,本文主要研究了DMM在酸性介质中的循环伏安行为随时间的变化情况,并用电化学方法验证了DMM的水解产物是甲醛和甲醇.     

MDR1, cholesterol certification and cell growth: a comparative study in normal and multidrug-resistant KB cell lines

The product of the MDR1 gene (P-gp) has been implicated in the transport of cholesterol from plasma membrane to endoplasmic reticulum for esterification. In previous studies on leukemia cell lines, we suggested that cholesterol esterification may regulate the rate of cell growth and that the MDR1 gene might be involved in this process by modulating intracellular cholesterol esters levels. To further investigate this matter, the rate of cell growth, cholesterol metabolism, expression of the MDR1 gene, and P-gp activity were compared in KB cell lines displaying differences in expression and function of P-gp (drug-sensitive phenotype versus MDR phenotype). The rate of cell growth correlated with cholesterol esterification in all KB cell lines, whereas the over-expression of MDR1 observed in the MDR cell lines was not always associated with an increased capacity of cells to esterify cholesterol. Two known inhibitors of P-gp activity, progesterone and verapamil, strongly inhibited both cholesterol esterification and cell proliferation in all KB cell lines, but they affected intracellular accumulation of labeled vinblastine only in MDR cell lines. These results further support a role for cholesterol esters in the regulation of cell growth and suggest that the P-gp expressed in MDR KB cells is not involved in the general process leading to cholesterol esterification. Received 14 February 2000; received after revision 10 April 2000; accepted 8 May 2000     

一种新型电池的开发和研究

本文从燃料电池在国内发展的技术状况,各类型燃料电池特性对比,结合我国国情,提出了我国应研究开发熔融碳酸盐燃料电池的建议和设想。     

The role of repair in radiobiology

Summary Apart from cancer and mutation induction, radiobiological effects on mammals are mostly attributable to cell death, defined as loss of proliferative capacity. Survival curves relate retention of that capacity to radiation dose, and often manifest a quasi-threshold (shoulder). The shoulder is attributable to an initial mechanism of repair (Q-repair) which is gradually depleted as dose increases. Another form of repair, which is not depleted (P-repair), increases the dose required to deliver an average of one lethal event per cell (dose D₀). Neither form of repair can unambiguously be linked with repair of defects in isolated DNA. An important initial lesion may well be disruption of the complex structural relationship between the DNA, nuclear membrane and associated proteins. One form of P-repair may be restoration of that structural relationship.     

Superoxide dismutase activity during the plasmodial life cycle ofPhysarum polycephalum

Summary Superoxide dismutase activity was slow throughout the cell cycle of surface cultures ofPhysarum polycephalum. This activity increased markedly when the organism was induced to spherulate. Glutathione (GSH) and hydrogen peroxide (H₂O₂) concentrations changed very little during the cell cycle. During spherulation GSH decreased; H₂O₂ and the cyanide-resistant respiration of plasmodial homogenates increased.     

Rho激酶抑制剂诱导PC12和PC12Adh细胞突起生长的差异比较

 PC12细胞是研究神经分化最常用的细胞之一.在rho激酶(ROCK)抑制剂的作用下,PC12细胞能够长出神经样突起.最近,美国菌种保存中心(ATCC)同时提供PC12细胞和PC12 Adh细胞.研究的主要目的是观察ROCK抑制剂诱导这2种细胞长突起是否存在差异.PC12细胞和PC12Adh细胞按照ATCC方法进行培养,用神经生长因子(NGF,1000ng/mL)或ROCK抑制剂(33μmol/L Y27632,33μmol/L法舒地尔)处理细胞1~4d.结果发现NGF能够诱导这2种细胞生长突起,而ROCK抑制剂只诱导PC12Adh细胞长突起,对PC12细胞不明显.因此,ROCK抑制剂诱导这2种细胞突起生长存在明显差异,PC12Adh细胞更适合用于ROCK抑制剂的神经诱导分化实验.     

Cell evolutionary algorithm: a new optimization method on ground-state energy of the atomic

The purpose of this paper is to present a new general approach to solve ground-state energies of the double-electron systems in a uniform magnetic field, in which the basic element of evolution is the set in the solution space, rather than the point. The paper defines the Cell Evolutionary Algorithm, which implements such a view of the evolution mechanism. First, the optimal set in which the optimal solution may be obtained. Then this approach applies the embedded search method to get the optimal solution. We tested this approach on the atomic structure, and the results show that it can improve not only the efficiency but also the accuracy of the calculations as it relates to this specific problem. Foundation item: Supported by the opening Foundation of state key Laboratory of Magnetic Resonance and Atomic and Molecular physics, Wuhan Institute of physics, Chinese Academy of Science (981510) Biography: Liu Lian-jun(1946-), female, Associate professor, research direction: atom and molecular physics.     

缺血性脑血管病与神经细胞凋亡的研究进展

叙述了细胞凋亡概念及神经细胞凋亡的基本特征。细胞凋亡是迟发性神经元死亡的基本形式，细胞凋亡在短暂性局灶性脑缺血、短暂性全脑缺血及永久性脑缺血中随缺血时间再灌注时间的不同，细胞凋亡发生部位及时间、范围亦不相同。     

鲫鱼尾部神经分泌系统Dahlgren细胞季节性变化的细胞计量学研究

本文用光镜和彩色图像分析系统,研究了雌性鲫鱼尾部神经分泌系统Dahlgren细胞的定量细胞学的季节性变化特点.结果发现:尾部最后7～12节脊髓中Dahlgren细胞的大小,在相邻季节间的变化为;从春至冬,逐渐减小（仅夏秋间无明显变化）,冬季后又逐渐增大,差异均极显著;而最后1～3节的变化为:只在春夏之间减小,夏季后则不断增大,差异也极显著.上述Dahlgren细胞计量学的变化,不同程度地呈现出与卵巢同步发育的关系.这为尾部神经分泌系统的变化与鱼类性成熟的相关性提供了新的依据.