南海东北部下地壳高速层的成因探讨

通过对南海北部大陆边缘地壳结构分析，指出南海东北部存在下地壳高速层，

Microarray Analyses of Gene Expression during the Tetrahymena thermophila Life Cycle

Background: The model eukaryote, Tetrahymena thermophila, is the first ciliated protozoan whose genome has been sequenced, enabling genome-wide analysis of gene expression. Methodology/Principal Findings: A genome-wide microarray platform containing the predicted coding sequences (putative genes) for T. thermophila is described, validated and used to study gene expression during the three major stages of the organism's life cycle: growth, starvation and conjugation. Conclusions/Significance: Of the,27,000 predicted open reading frames, transcripts homologous to only,5900 are not detectable in any of these life cycle stages, indicating that this single-celled organism does indeed contain a large number of functional genes. Transcripts from over 5000 predicted genes are expressed at levels >5x corrected background and 95 genes are expressed at >250x corrected background in all stages. Transcripts homologous to 91 predicted genes are specifically expressed and 155 more are highly up-regulated in growing cells, while 90 are specifically expressed and 616 are up-regulated during starvation. Strikingly, transcripts homologous to 1068 predicted genes are specifically expressed and 1753 are significantly up-regulated during conjugation. The patterns of gene expression during conjugation correlate well with the developmental stages of meiosis, nuclear differentiation and DNA elimination. The relationship between gene expression and chromosome fragmentation is analyzed. Genes encoding proteins known to interact or to function in complexes show similar expression patterns, indicating that co-ordinate expression with putative genes of known function can identify genes with related functions. New candidate genes associated with the RNAi-like process of DNA elimination and with meiosis are identified and the late stages of conjugation are shown to be characterized by specific expression of an unexpectedly large and diverse number of genes not involved in nuclear functions.

P-选择素CR结构域功能的模拟预测

<正>选择素(selectin)与其配体间相互作用介导的细胞粘附在炎症级联反应、肿瘤转移和淋巴细胞归巢等病理、生理过程中起重要作用。其结构组成从远离细胞表面的N-末端到胞内C-末端,依次为:钙型凝集素功能区(Calcium-type lectin domain,Lec),类上皮生长因子功能区(Epidermal Growth Factor-like module,EGF),具有粘附补体蛋白作用的多个重复序列(Consensus Repeats,CRs),跨膜区(Transmembrane,TM)和胞内区

ECR离子源高电荷态金属离子产生的MIVOC法实验研究

为满足兰州重离子加速器的实验要求,先后在中国科学院近代物理研究所14.5GHz(LECR2)及10GHz+14.5GHz(LECR3)高电荷态ECR离子源上使用MIVOC(Metallic ion fromvolatile compounds)方法进行了高电荷态金属离子产生的实验研究。主要研究了铁和镍的各种高电荷态离子的产生,具有代表性的是210eμA的Fe11+、175eμA的Fe12+、142eμA的Fe13+、25eμA的Fe16+、64eμA的Ni10+、57eμA的Ni13+、31eμA的Ni15+和15eμA的Ni16+。本文将分别给出两种金属离子产生的多电荷态束流谱图,并对实验装置的安排、实验现象及结果进行讨论与总结。

Preparation and characterization of CdS nanotubes and nanowires by electrochemical synthesis in ion-track templates

CdS nanotubes and nanowires have been synthesized with controlled dimensions by means of template-electrodeposition method in etched ion-track membranes. The diameters of nanotubes and nanowires are between 20 and I 10 nm, and the lengths are up to tens of micrometers. X-ray diffraction (XRD) and selected area electron diffraction (SAED) pattern investigations demonstrate that CdS nanotubes and nanowires are polycrystalline in nature. The UV-vis absorption spectra of CdS nanotubes and nanowires embedded in polycarbonate (PC) membranes show that the absorption edges of PC films shift towards the shorter wavelength, with decreasing diameters of the deposited nanostructures. The results indicate that nanowires are formed from nanotubes by nanotube-stuffing-growth mechanism.

《中国沙地森林生态系统》评介

沙地森林是分布我国草原地区沙地上的大（中）高位芽植物为建群种形成的森林群落．由于其独特的生态条件、丰富的生物多样性和重要的生态系统功能，对我国北方防风固沙、控制土地沙漠化，改善当地农牧区人民生活环境以及三北防护林体系建设发挥巨大的生态效益、经济效益和...

东北松辽平原农业资源的开发措施

东北松辽平原农业资源的开发措施王春裕（中国科学院沈阳应用生态研究所，沈阳１１００１５）王曦（辽宁省科学技术信息中心，沈阳１１００１５）松辽平原是我国东北地区松花江与辽河的冲积平原，南北长１０００多ｋｍ，东西宽４００多ｋｍ，地势平坦，土质肥沃，河）１１...