路连接双圈图Hosoya指标的最大值序列

路连接双圈图是指两个圈用一条路相连接的图.本文章根据已有的结果,通过对Hosoya指标的理论和性质的研究,给出了路连接双圈图Hosoya指标的最大值序列图及其最大值图.     

Two enzymes bound to one transfer RNA assume alternative conformations for consecutive reactions

In most bacteria and all archaea, glutamyl-tRNA synthetase (GluRS) glutamylates both tRNA(Glu) and tRNA(Gln), and then Glu-tRNA(Gln) is selectively converted to Gln-tRNA(Gln) by a tRNA-dependent amidotransferase. The mechanisms by which the two enzymes recognize their substrate tRNA(s), and how they cooperate with each other in Gln-tRNA(Gln) synthesis, remain to be determined. Here we report the formation of the 'glutamine transamidosome' from the bacterium Thermotoga maritima, consisting of tRNA(Gln), GluRS and the heterotrimeric amidotransferase GatCAB, and its crystal structure at 3.35 A resolution. The anticodon-binding body of GluRS recognizes the common features of tRNA(Gln) and tRNA(Glu), whereas the tail body of GatCAB recognizes the outer corner of the L-shaped tRNA(Gln) in a tRNA(Gln)-specific manner. GluRS is in the productive form, as its catalytic body binds to the amino-acid-acceptor arm of tRNA(Gln). In contrast, GatCAB is in the non-productive form: the catalytic body of GatCAB contacts that of GluRS and is located near the acceptor stem of tRNA(Gln), in an appropriate site to wait for the completion of Glu-tRNA(Gln) formation by GluRS. We identified the hinges between the catalytic and anticodon-binding bodies of GluRS and between the catalytic and tail bodies of GatCAB, which allow both GluRS and GatCAB to adopt the productive and non-productive forms. The catalytic bodies of the two enzymes compete for the acceptor arm of tRNA(Gln) and therefore cannot assume their productive forms simultaneously. The transition from the present glutamylation state, with the productive GluRS and the non-productive GatCAB, to the putative amidation state, with the non-productive GluRS and the productive GatCAB, requires an intermediate state with the two enzymes in their non-productive forms, for steric reasons. The proposed mechanism explains how the transamidosome efficiently performs the two consecutive steps of Gln-tRNA(Gln) formation, with a low risk of releasing the unstable intermediate Glu-tRNA(Gln).     

带运输时间和一个不可用约束的两台平行机排序

考虑了两台平行机的排序问题,其中一台机器带有一个固定的不可用约束区间,任务的加工是不可中断的,而且每一个任务带有一个运输时间,目标函数是最小化最大运输完工时间.这个问题是强NP-难的.提出一个最坏情况比是8/5的多项式时间近似算法,并指出这个界是紧界.同时还用动态规划方法求解该问题.     

一类非自治的两互惠捕食者-食饵系统的动力学行为

研究了非自治的捕食者-食饵模型.该系统是两个具有互惠关系的捕食者种群捕食一个食饵种群.利用比较原理研究了系统的持久性,通过构造Liapunov函数证明了系统的全局渐近稳定性,在假设系统为周期系统的条件下得到了正周期解的存在唯一性和全局渐近稳定的充分条件.     

论在一个微波信道中同时传输两路电视信号

本文论述了在我国现有微波系统中,利用双载波和时间压扩技术实现在一个微波信道上同时传输两路电視信号的方案     

亿万富豪创业四大宝典

上海的创业氛围日渐浓厚，却仍有很 多人苦于资金不足而迟迟未能走上创业 路，但上海德力西集团总裁胡成国，这位 在上世纪80年代凭借5万元的高息贷款起 家创业，终于搏得今日过亿身价的民营企 业家却觉得，5万元已经足够起家的成本 了。有意思的是，对这位儒雅的温州人来 说，赚钱是比较容易的事情，相反，花钱 却是困难的。 创业心得： 1)要有信心。任何企业都要经过从小 到大的发展过程，5年或者10年以后，你 一样有可能成为富豪榜的新贵。 2)如果不是自己创业，找好合伙人是 关键，要善于从合伙人那里得到资源的最 佳配置。 穿10元钱一件的衬衫，不开奔驰开 老尼桑，睡得早没有夜生活，这个成功的     

Two types of cholinergic innervation in cortex, one co-localized with vasoactive intestinal polypeptide

The existence of cholinergic neuronal cell bodies in mammalian cerebral cortex was long the subject of much controversy (see ref. 1 for review). Recently, however, a specific cholinergic marker, the acetylcholine synthesizing enzyme, choline acetyltransferase (ChAT, E.C.2.3.1.6), was demonstrated by immunohistochemical methods to be present in bipolar neurones in rat cortex. Here we show that at least 80% of these intrinsic cholinergic neurones also contain immunoreactivity for vasoactive intestinal polypeptide (VIP), a neuroactive peptide found to be present in a subpopulation of cortical neurones. On the other hand, we find that the ChAT-positive cells in the basal forebrain, which are another major source of cholinergic innervation of the cortex, contain no detectable VIP-immunoreactivity. In addition, we have observed by both light and electron microscopy that some VIP- and some ChAT-positive structures in cortex are closely associated with blood vessels.     

如何成为高职高专类教学能手

针对高职高专教育人才培养模式的基本特征以及将素质教育贯穿于高职高专教育人才培养工作始终的特点,该文围绕课前准备、课堂组织、教学方法、师生交流等方面来阐述如何成为高职高专类教学能手。     

草菇胞外高丰度蛋白质的分离测序及cDNA片段克隆

经过柱层析,从以稻草粉为基质培养的草菇(Volvariella volvacea)摇瓶发酵液中纯化了HEP1(h ighexpressional protein 1)和HEP2(h igh expressional protein 2)两个在胞外高丰度存在的蛋白质.SDS-PAGE电泳和分子筛层析的结果表明HEP1和HEP2的相对分子质量分别是52.6×103和26.2×103,且都是单亚基.其中HEP1经过酶解印迹后对肽段N端前15个氨基酸进行测序.根据测序结果设计简并引物,PCR扩增到一条长约750 bp特异核酸条带.克隆测序后,该cDNA片段经GenBank多序列比对,未发现其属于某个特定的基因家族.     

一类恰含两个s长圈和一个p长圈的n阶本原有向图的scrambling指数

对一类特殊本原有向图的scrambling指数进行研究,其恰含有两个s长圈和一个p长圈,通过分析图的特点,结合本原有向图scrambling指数的定义与性质,进而得出这一类本原有向图的scrambling指数.