E-n-伪矩形性拟正则半群

本文是在[1]的基础上,将半群s的幂等元集E(S)由埋想推广为n-伪理想,然后来给出S的结构。本文未用到格林关系,因而证明有别于[1],而且[1]是我们的特例。     

叶绿素衍生物CPD4在人血清中的吸收光谱

研究了不同浓度（１０、５０μｇ／ｍｌ）的叶绿素衍生物４号（ＣＰＤ４）在含１０％不同血清人血清（分Ａ、Ｂ、Ｏ型三种）生理盐水中以及纯蒸馏水中的吸收光谱，并对结果进行了分析和比较，该工作对ＣＰＤ４在ＰＤＴ临床上的应用具有一定的意义。．     

关于素性半群

引进素性半群（ｐｒｉｍａｌｓｅｍｉｇｒｏｕｐ）的概念，所谓素性半群，是指其中的素理想集构成一个全序集的半群，给出一个半群Ｓ为素性半群的充要条件是其中任意两个Ｓ的素理想Ａ及Ｂ的交为Ａ∪Ｂ的素理想，并且讨论了一些素理想的有关性质。     

太阳电池I－V数据采集系统

本文利用ＩＥＥＥ－４８８接口板，Ｋｅｉｔｈｌｅｙ６１７静电计，ＩＢＭ－ＰＣ微机，编程实现了太阳电池Ｉ－Ｖ数据的自动采集、存储．以ａ－Ｓｉ：ＨＰｉｎ型太阳电池为样品，计算出相应的电池参量，验证了该系统的可行性和准确性．     

Ca2+ release induced by inositol 1,4,5-trisphosphate is a steady-state phenomenon controlled by luminal Ca2+ in permeabilized cells.

Low concentrations of inositol 1,4,5-trisphosphate (InsP3) evoke a very rapid mobilization of intracellular Ca2+ stores in many cell types, which can be followed by a further, much slower efflux. Two explanations have been suggested for this biphasic release. The first proposes that the Ca2+ stores vary in their sensitivity to InsP3, and each store releases either its entire contents or nothing (all-or-none release); the second proposes instead that the stores are uniformly sensitive to the effects of InsP3, but that they can release only a fraction of their Ca2+ before their sensitivity is somehow attenuated (steady-state release). Experiments using purified InsP3 receptor molecules reconstituted into lipid vesicles have shown heterogeneity of the receptors in their response to InsP3 under conditions in which the total Ca2+ level at both sides of the receptor is held constant. We now report that in permeabilized A7r5 smooth-muscle cells incubated in Ca(2+)-free medium, the amount of 45Ca2+ remaining in the stores after the rapid transient phase of release is independent of their initial Ca2+ levels, indicating that partially depleted stores are less sensitive to InsP3. Moreover, if the stores are reloaded with 40Ca2+ after the first stimulus, reapplication of the same low concentration of InsP3 will release further 45Ca2+. This recovery of InsP3 sensitivity is almost complete. Under these conditions, Ca2+ release must thus occur by a steady-state mechanism, in which the decreasing Ca2+ content of the stores slows down further release.     

Activation of a C. elegans Antennapedia homologue in migrating cells controls their direction of migration.

Anterior-posterior patterning in insects, vertebrates and nematodes involves members of conserved Antennapedia-class homeobox gene clusters (HOM-C) that are thought to give specific body regions their identities. The effects of these genes on region-specific body structures have been described extensively, particularly in Drosophila, but little is known about how HOM-C genes affect the behaviours of cells that migrate into their domains of function. In Caenorhabditis elegans, the Antennapedia-like HOM-C gene mab-5 not only specifies postembryonic fates of cells in a posterior body region, but also influences the migration of mesodermal and neural cells that move through this region. Here we show that as one neuroblast migrates into this posterior region, it switches on mab-5 gene expression; mab-5 then acts as a developmental switch to control the migratory behaviour of the neuroblast descendants. HOM-C genes can therefore not only direct region-specific patterns of cell division and differentiation, but can also act within migrating cells to programme region-specific migratory behaviour.