细菌DNA序列中的长程相关性

为了深入研究基因组序列的长程相关性质,将一些估计序列长程相关因数的参数化方法引入脱氧核糖核酸（ Ｄ Ｎ Ａ）序列自相似结构的研究之中。与 Ｆｏｕｒｉｅｒ 分析方法比较,这些参数化方法的结果更加稳定可靠。应用这些方法,该文对 ８ 种细菌 Ｄ Ｎ Ａ 全序列进行了统计分析,发现在细菌 Ｄ Ｎ Ａ 序列中存在着长程相关结构,其存在范围可以延伸到整个 Ｄ Ｎ Ａ 分子。粗粒化过程的高阶累积量检验表明 Ｄ Ｎ Ａ序列中存在的是单分形结构,在较大尺度下可以渐近地用分数高斯噪声过程来建模。这为进一步分析和理解 Ｄ Ｎ Ａ 序列的组织形式和功能行使方式提供了新的思路。     

A modified non-homogeneous model for codon preference and primary sequence structure in protein-coding regions

Based on non-homogeneous model, a modified model is proposed. The new model deals with codon preference in protein-coding regions, reflects more accurately the key biological features of the regions. In addition, it is demonstrated, via an example, the modified model offers better solutions than previous model does. Foundation item: Supported by the Zi-qiang Science Foundation of Wuhan University Biography: Han Le (1977-), female, Master candidate, research direction: optimization and bioinformatics     

The genome sequence of Bacillus anthracis Ames and comparison to closely related bacteria

Bacillus anthracis is an endospore-forming bacterium that causes inhalational anthrax. Key virulence genes are found on plasmids (extra-chromosomal, circular, double-stranded DNA molecules) pXO1 (ref. 2) and pXO2 (ref. 3). To identify additional genes that might contribute to virulence, we analysed the complete sequence of the chromosome of B. anthracis Ames (about 5.23 megabases). We found several chromosomally encoded proteins that may contribute to pathogenicity--including haemolysins, phospholipases and iron acquisition functions--and identified numerous surface proteins that might be important targets for vaccines and drugs. Almost all these putative chromosomal virulence and surface proteins have homologues in Bacillus cereus, highlighting the similarity of B. anthracis to near-neighbours that are not associated with anthrax. By performing a comparative genome hybridization of 19 B. cereus and Bacillus thuringiensis strains against a B. anthracis DNA microarray, we confirmed the general similarity of chromosomal genes among this group of close relatives. However, we found that the gene sequences of pXO1 and pXO2 were more variable between strains, suggesting plasmid mobility in the group. The complete sequence of B. anthracis is a step towards a better understanding of anthrax pathogenesis.     

The epidermis both drives and restricts plant shoot growth

The size of an organism is genetically determined, yet how a plant or animal achieves its final size is largely unknown. The shoot of higher plants has a simple conserved body plan based on three major tissue systems: the epidermal (L1), sub-epidermal (L2) and inner ground and vascular (L3) tissues. Which tissue system drives or restricts growth has been a subject of debate for over a century. Here, we use dwarf, brassinosteroid biosynthesis and brassinosteroid response mutants in conjunction with tissue-specific expression of these components as tools to examine the role of the epidermis in shoot growth. We show that expression of the brassinosteroid receptor or a brassinosteroid biosynthetic enzyme in the epidermis, but not in the vasculature, of null mutants is sufficient to rescue their dwarf phenotypes. Brassinosteroid signalling from the epidermis is not sufficient to establish normal vascular organization. Moreover, shoot growth is restricted when brassinosteroids are depleted from the epidermis and brassinosteroids act locally within a leaf. We conclude that the epidermis both promotes and restricts shoot growth by providing a non-autonomous signal to the ground tissues.     

稠油解烃菌与乳化剂产生菌复配降解降粘机理

油杆菌W3分离自江苏油田韦5井,能够以稠油为唯一碳源生长并降解稠油。54℃好氧振荡培养7天之后,稠油能够完全乳化分散到培养中,降粘率达到了76.88%,降解速率达到了99.7 mg/天,原油族组分分析发现,稠油中饱和烃,芳香烃和胶质的含量分别降低了4.14%,6.77%和4.33%。该菌与另一株筛选得到的能够合成乳化剂的地芽孢杆菌W12复配（VW3:VW12=1:1）后作用稠油,既能够增强稠油降解效果（降解速率加快,原油族组分含量进一步降低）,又能够改善稠油的乳化分散状态（乳化稳定性增强,平均乳化粒径减小56.7%）,此时的稠油的乳化粘度为20.59 mPa?s,仅为初始粘度的3.9%。这两株菌的复配增强了稠油降解和乳化的双重降粘效果,大幅提高了稠油的流动性。     

滤波器的选择与安装

滤波与屏蔽、接地共同构成完善的电磁干扰防护,介绍如何正确选择与安装滤波器,利用其衰减特性,使其对电磁干扰的抑制作用达到预期的效果。     

基于MRAS的感应电机无速度传感器矢量控制

提出了一种基于模型参数自适应系统（MRAS）的感应电机转子速度估算方法,用电机状态方程构成全阶观测器观测定子电流和转子磁链,利用李雅普诺夫第二法推导出转速估算公式,并在理论上证明了系统的全局渐近稳定性．分析了定子电阻和转子电阻的变化对转速估算的影响,并对严重影响速度估算的定子电阻的变化进行了补偿,从而构成无速度传感器感应电机间接磁场定向控制系统．仿真结果表明,该系统在低速下具有较好的转矩转速特性以及良好的抗干扰性．     

The translational landscape of mTOR signalling steers cancer initiation and metastasis

The mammalian target of rapamycin (mTOR) kinase is a master regulator of protein synthesis that couples nutrient sensing to cell growth and cancer. However, the downstream translationally regulated nodes of gene expression that may direct cancer development are poorly characterized. Using ribosome profiling, we uncover specialized translation of the prostate cancer genome by oncogenic mTOR signalling, revealing a remarkably specific repertoire of genes involved in cell proliferation, metabolism and invasion. We extend these findings by functionally characterizing a class of translationally controlled pro-invasion messenger RNAs that we show direct prostate cancer invasion and metastasis downstream of oncogenic mTOR signalling. Furthermore, we develop a clinically relevant ATP site inhibitor of mTOR, INK128, which reprograms this gene expression signature with therapeutic benefit for prostate cancer metastasis, for which there is presently no cure. Together, these findings extend our understanding of how the 'cancerous' translation machinery steers specific cancer cell behaviours, including metastasis, and may be therapeutically targeted.     

陕西省工业战略产业的选择

结合陕西省工业发展情况，根据战略产业选择的原则，选出了10项战略产业评价指标，利用Weaver-Thomas模型与FoxBASE^ 计算机语言得出了16个战略产业，并分析与评价了选择出的结果．陕西处在从重工业化向高加工度化转变的阶段初期，制约陕西工业发展的因素为：加工工业的规模不够大、工业战略产业系统技术水平低、技术进步速度慢等．最后，提出了发展战略产业、促进经济快速增长的建议．     

The consideration and choice on exploiting energy source

A problem of petroleum energy crisis will probably be faced in the late 21st century. It is impossible to discover the giant oil fields again based on the traditional knowledge and theory of petroleum geology. From the global development point of view as well as the situation in China, the five choices of energy source in the future are to (i) extend the field of exploration in conventional petroleum and natural gas source, and exploit oil-gas source in ocean and some basins of northwestern China; (ii) discover unconventional oil and natural gas source: abiogenic gas, deep oil and gas, gas hydrates, coal bed gas and so on; (iii) develop techniques of cleansing, gasifying and liquefying coal for highly effective utilization, and transform coal into electricity and at the same time pay attention to the environment protection and pollution control as well; (iv) carry out researches on the theory and technology of producing and storing hydrogen in order to seek for its effective and economical utilization; (v) pay attention to and carry out the research in advance on exploiting the source of³He isotope on the moon and using the D-³He controlled nuclear fusion as fuel.     

基于NETCONF的通用转换网关模型的研究和实现

随着下一代网络的出现，基于XML网络管理已经成为网络管理研究的热点．在XML网络管理中，协议转换网关可以实现基于XML、SNMP和非SNMP设备的兼容性管理．本文提出了一种基于NETCONF的通用协议转换网关模型，研究了其中的关键技术，并给出了验证该模型可行性的实现方案．该通用转换模型可以实现综合网络管理中多种网络管理协议格式的统一自动转换，相比传统的单一性转换网关具有统一性、灵活性的特点．     

Evidence for lateral gene transfer between Archaea and bacteria from genome sequence of Thermotoga maritima.

The 1,860,725-base-pair genome of Thermotoga maritima MSB8 contains 1,877 predicted coding regions, 1,014 (54%) of which have functional assignments and 863 (46%) of which are of unknown function. Genome analysis reveals numerous pathways involved in degradation of sugars and plant polysaccharides, and 108 genes that have orthologues only in the genomes of other thermophilic Eubacteria and Archaea. Of the Eubacteria sequenced to date, T. maritima has the highest percentage (24%) of genes that are most similar to archaeal genes. Eighty-one archaeal-like genes are clustered in 15 regions of the T. maritima genome that range in size from 4 to 20 kilobases. Conservation of gene order between T. maritima and Archaea in many of the clustered regions suggests that lateral gene transfer may have occurred between thermophilic Eubacteria and Archaea.     

基于ETCONF的通用转换网关模型的研究和实现

随着下一代网络的出现,基于XML网络管理已经成为网络管理研究的热点.在XML网络管理中,协议转换网关可以实现基于XML、SNMP和非SNMP设备的兼容性管理.本文提出了一种基于NETCONF的通用协议转换网关模型,研究了其中的关键技术,并给出了验证该模型可行性的实现方案.该通用转换模型可以实现综合网络管理中多种网络管理协议格式的统一自动转换,相比传统的单一性转换网关具有统一性、灵活性的特点.     

线性平移策略降低算法复杂度的研究与实践

平移策略在线性算法研究中具有广泛的使用价值,主要的应用方法为相对定长平移和线性段整体平移两种策略,应用平移策略可以对算法以及算法的特定部分进行改进,从而降低算法复杂性,提高运行效率.主要以计算机专业硕士研究生考试和经典KMP算法为案例,通过实验比较得出最优算法的过程.     

The codon CUG is read as serine in an asporogenic yeast Candida cylindracea

Deviations from the universal genetic code have been reported for several microorganisms. Termination codons are used for coding some amino acids in Paramecium, Mycoplasma or Tetrahymena, and in Escherichia coli, the UGA termination codon is used to code for selenocysteine. In mitochondria, the changes of sense codons to termination codons or to codons encoding other amino acids have also been reported. Here we report another example of divergence from the universal code, this time in a non-spore-forming yeast Candida cylindracea, in which the universal codon for leucine, CUG, is used to code for serine. This conclusion is based on the observations that: (1) the amino-acid composition and the partial amino-acid sequences of an extracellular lipase from this yeast agreed with those deduced from the complementary DNA if CUG was assumed to specify serine; and (2) serine, but not leucine, was incorporated into a polypeptide in a cell-free translation system from this yeast in the presence of a synthetic CUG oligomer.     

序列覆盖ss映射与cs网

以一种简单方式给出了局部可分度量空间几类序列覆盖ss映象的特征。     

长新高架桥桥型选择与结构分析

重点分析了江密峰至延吉高速公路长新高架桥桥型选择和上部结构的采用,并详细介绍了预应力混凝土连续刚构桥的结构分析和施工工序。