太原市二氧化硫污染状况及评价

通过对太原市不同季节、不同监测位点大气二氧化硫(SO2)浓度的监测，分析了太原市SO2污染状况，指出在太原市对SO2排放企业的治理和管理工作势在必行。     

Crystal structure of human cytochrome P450 2C9 with bound warfarin

Cytochrome P450 proteins (CYP450s) are membrane-associated haem proteins that metabolize physiologically important compounds in many species of microorganisms, plants and animals. Mammalian CYP450s recognize and metabolize diverse xenobiotics such as drug molecules, environmental compounds and pollutants. Human CYP450 proteins CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A4 are the major drug-metabolizing isoforms, and contribute to the oxidative metabolism of more than 90% of the drugs in current clinical use. Polymorphic variants have also been reported for some CYP450 isoforms, which has implications for the efficacy of drugs in individuals, and for the co-administration of drugs. The molecular basis of drug recognition by human CYP450s, however, has remained elusive. Here we describe the crystal structure of a human CYP450, CYP2C9, both unliganded and in complex with the anti-coagulant drug warfarin. The structure defines unanticipated interactions between CYP2C9 and warfarin, and reveals a new binding pocket. The binding mode of warfarin suggests that CYP2C9 may undergo an allosteric mechanism during its function. The newly discovered binding pocket also suggests that CYP2C9 may simultaneously accommodate multiple ligands during its biological function, and provides a possible molecular basis for understanding complex drug-drug interactions.     

The secreted form of the Alzheimer's amyloid precursor protein with the Kunitz domain is protease nexin-II

The A4 protein (or beta-protein) is a 42- or 43-amino-acid peptide present in the extracellular neuritic plaques in Alzheimer's disease and is derived from a membrane-bound amyloid protein precursor (APP). Three forms of APP have been described and are referred to as APP695, APP751 and APP770, reflecting the number of amino acids encoded for by their respective complementary DNAs. The two larger APPs contain a 57-amino-acid insert with striking homology to the Kunitz family of protease inhibitors. Here we report that the deduced amino-terminal sequence of APP is identical to the sequence of a cell-secreted protease inhibitor, protease nexin-II (PN-II). To confirm this finding, APP751 and APP695 cDNAs were over-expressed in the human 293 cell line, and the secreted N-terminal extracellular domains of these APPs were purified to near homogeneity from the tissue-culture medium. The relative molecular mass and high-affinity binding to dextran sulphate of secreted APP751 were consistent with that of PN-II. Functionally, secreted APP751 formed stable, non-covalent, inhibitory complexes with trypsin. Secreted APP695 did not form complexes with trypsin. We conclude that the secreted form of APP with the Kunitz protease inhibitor domain is PN-II.     

化学镀镍废液处理新工艺及机理研究

通过化学沉淀法从废液中回收镍离子，继而采用硫酸亚铁为共沉剂，进一步处理上述废液，达到去除剩余镍离子的目的，考察了双氧水、氢氧化钠、硫酸亚铁用量及反应时间对化学镀镍废液处理结果的影响，并对反应机理进行了初步探讨，结果表明，新工艺双氧水用量少、回收镍纯度高，经济可行。     

基于一种扩展分层有限状态机模型的测试生成

为了解决分层有限状态机(HFSM)中数据和约束的问题,对扩展分层有限状态机(E-HFSM)给出了定义对其特征进行了分析,对基于其上的模型所面临的测试问题进行了讨论.考虑了在测试中遇到的控制流和数据流问题,针对其中一种模型(父子EHFSM间不存在数据依赖关系),结合现有的方法工具给出了一种一致性测试生成方法.     

Nd：YAG激光器的光泵效率比较实验研究

在利用IGBT斩波电路控制闪光灯放电波形的Nd:YAG脉冲激光器中,进行了分别采用双脉冲氙灯串联、双脉冲氪灯串联、单支脉冲氙灯和单支脉冲氪灯作为泵浦源的实验。实验结果表明,在储能电容初始放电电压为400V的条件下,采用单支脉冲氪灯泵浦的电光效率最高。     

The NCBI dbGaP database of genotypes and phenotypes

The National Center for Biotechnology Information has created the dbGaP public repository for individual-level phenotype, exposure, genotype and sequence data and the associations between them. dbGaP assigns stable, unique identifiers to studies and subsets of information from those studies, including documents, individual phenotypic variables, tables of trait data, sets of genotype data, computed phenotype-genotype associations, and groups of study subjects who have given similar consents for use of their data.     

Mutations in DNMT1 cause hereditary sensory neuropathy with dementia and hearing loss

DNA methyltransferase 1 (DNMT1) is crucial for maintenance of methylation, gene regulation and chromatin stability. DNA mismatch repair, cell cycle regulation in post-mitotic neurons and neurogenesis are influenced by DNA methylation. Here we show that mutations in DNMT1 cause both central and peripheral neurodegeneration in one form of hereditary sensory and autonomic neuropathy with dementia and hearing loss. Exome sequencing led to the identification of DNMT1 mutation c.1484A>G (p.Tyr495Cys) in two American kindreds and one Japanese kindred and a triple nucleotide change, c.1470-1472TCC>ATA (p.Asp490Glu-Pro491Tyr), in one European kindred. All mutations are within the targeting-sequence domain of DNMT1. These mutations cause premature degradation of mutant proteins, reduced methyltransferase activity and impaired heterochromatin binding during the G2 cell cycle phase leading to global hypomethylation and site-specific hypermethylation. Our study shows that DNMT1 mutations cause the aberrant methylation implicated in complex pathogenesis. The discovered DNMT1 mutations provide a new framework for the study of neurodegenerative diseases.     

Earliest Homo.

The origin of our own genus, Homo, has been tentatively correlated with worldwide climatic cooling documented at about 2.4 Myr (million years). It has also been conjectured that members of Homo made the first stone tools, currently dated at 2.6-2.4 Myr. But fossil specimens clearly attributable to Homo before about 1.9 Myr have been lacking. In 1967 a fossil hominoid temporal bone (KNM-BC1) from the Chemeron Formation of Kenya was described as family Hominidae gen. et sp. indet. Although a surface find, its provenance within site JM85 (BPRP site K002) was established and a stratigraphic section provided indicating the specimen's position. This evidence has been affirmed but the exact age of the fossil was never determined, and the absence of suitable comparative hominid material has precluded a more definitive taxonomic assignment. Here we present 40Ar/39Ar age determinations on material from the hominid site indicating an age of 2.4 Myr. In addition, comparative studies allow us to assign KNM-BC1 to the genus Homo, making it the earliest securely known fossil of our own genus found so far.