Cyclophosphamide-impaired regulation of hepatic heme metabolism

Summary Im male rats hepatic cytochromes b₅ and P-450 were reduced at different times after treatment with cyclophosphamide (CP) (200 mg/kg i.p. for 3 days). In contrast, microsomal heme did not change until 48 h after the last dose of CP, leading to accumulation of heme in a non-cytochromal form. Parallel to the above changes the heme metabolism showed derangement: -aminolaevulinate synthase, the rate-limiting enzyme in heme synthesis, was depressed and heme oxygenase, the enzyme which catalyzes the oxidative degradation of heme, was increased.     

大功率 LED 电学参数模型的研究

为精确描述大功率 LED(Light Emitting Diode)的伏安特性, 将经典的肖克莱方程与 LED 物理模型结合进 行理论推导, 对所得方程进行泰勒展开, 并对该模型进行分段处理, 构建了大功率 LED 的电学参数模型。 通过 实测大功率 LED 的伏安特性数据验证了本模型比经典 PN 结模型更接近实际的伏安特性曲线, 与实测曲线一 致性更高, 误差在 1%以内。     

Ebola virus entry requires the cholesterol transporter Niemann-Pick C1

Infections by the Ebola and Marburg filoviruses cause a rapidly fatal haemorrhagic fever in humans for which no approved antivirals are available. Filovirus entry is mediated by the viral spike glycoprotein (GP), which attaches viral particles to the cell surface, delivers them to endosomes and catalyses fusion between viral and endosomal membranes. Additional host factors in the endosomal compartment are probably required for viral membrane fusion; however, despite considerable efforts, these critical host factors have defied molecular identification. Here we describe a genome-wide haploid genetic screen in human cells to identify host factors required for Ebola virus entry. Our screen uncovered 67 mutations disrupting all six members of the homotypic fusion and vacuole protein-sorting (HOPS) multisubunit tethering complex, which is involved in the fusion of endosomes to lysosomes, and 39 independent mutations that disrupt the endo/lysosomal cholesterol transporter protein Niemann-Pick C1 (NPC1). Cells defective for the HOPS complex or NPC1 function, including primary fibroblasts derived from human Niemann-Pick type C1 disease patients, are resistant to infection by Ebola virus and Marburg virus, but remain fully susceptible to a suite of unrelated viruses. We show that membrane fusion mediated by filovirus glycoproteins and viral escape from the vesicular compartment require the NPC1 protein, independent of its known function in cholesterol transport. Our findings uncover unique features of the entry pathway used by filoviruses and indicate potential antiviral strategies to combat these deadly agents.     

Epigenetic asymmetry of imprinted genes in plant gametes

Plant imprinted genes show parent-of-origin expression in seed endosperm, but little is known about the nature of parental imprints in gametes before fertilization. We show here that single differentially methylated regions (DMRs) correlate with allele-specific expression of two maternally expressed genes in the seed and that one DMR is differentially methylated between gametes. Thus, plants seem to have developed similar strategies as mammals to epigenetically mark imprinted genes.     

土体侧向变形性状的真三轴试验研究

对标准砂和风干粘土的击实试样进行了真三轴应力应变关系试验研究，发现当某一方向给土体施加力应力增量而其侧向应力保持不变时，侧向变形未必都是膨胀的，也有可能是压缩的，即泊松比未比总是正值，而有时可能为负，这是一个值得重视的有异于经典力学理论的现象，本文研究了这一现象出现的规律，并从机理上分析了其发生的必然性和存在的条件。     

非嵌插类DNA结合药物的碱基序列特异性

本文讨论了非嵌插类DNA结合药物的碱基序列特异性,这对于探讨药物与DNA相互作用的分子机制是很有意义的。通过这些探索,得到了一些有意义的结果。     

一些困难问题的数值求解

基于微分方程系数的局部结构来构造微分方程的局部精确差分格式,新方法解决了一些用现有方法无法满意计算的困难问题。     

Notes on types of Australian Chartocerus Motschulsky (Hymenoptera: Signiphoridae)

ABSTRACT

Type specimens of 11 species of Chartocerus (Hymenoptera: Signiphoridae) from Australia described by A.A. Girault, in the collection of the Queensland Museum, and one species described by W.H. Ashmead, in the United States Museum of Natural History, are redescribed and illustrated. Lectotypes are designated for Chartocerus australiensis (Girault) and Chartocerus hebes (Girault).     

人工神经网络预测非饱和土的特征参数

针对测定非饱和土的吸力既费时,费钱,又困难,而且往往是通过水分特征曲线间接求取,以致其精度不够理想这一问题,尝试采用人工神经网络进行预测研究,将部分已有的试验数据（含水量,吸力数据）作为输入模式进行训练,然后利用网络参数进行相应的参数预测。结果表明,神经网络预测技术十分有效,为工程应用提供了一种新的工具。     

首山一矿聚能双掏槽光面爆破技术应用

为适应平宝公司岩巷掘进的巨大需求,满足矿井采掘布局的进一步优化需要。针对岩巷掘进施工时打眼多、装药多、光面爆破效果差、工效低的现状,分析了原有爆破方式施工存在的问题及原因,在常规岩巷光面爆破的基础上,利用理论分析,室内试验,现场试验等手段,研究开发了聚能水压双掏槽光面爆破技术,并在平宝公司首山一矿进行了应用。工程实践表明,该方法大幅度降低炮眼掘进量,雷管、炸药等消耗量,降低爆破材料费。有效提升了岩巷光面爆破效果、增加了循环炮进率,岩巷光爆效果得到了明显的提升。在相同的条件下进尺效率得到了提高,在满足工程质量的同时,降低了施工成本,更加节能环保。