Left-handed DNA in restriction fragments and a recombinant plasmid

Circular dichroism and 31P-NMR on synthetic oligomers of (dC-dG) inserted within DNA restriction fragments indicate that the right-handed B-structure can exist in close proximity to the left-handed Z-structure. Also, this salt-induced transition to Z-form in a small (dC-dG) segment (1.3%) of a recombinant plasmid markedly influenced the supercoil of the plasmid. These observations have implications for the postulated role of naturally occurring related simple sequences in the regulation of gene activity.     

Domination of heliosheath pressure by shock-accelerated pickup ions from observations of neutral atoms

The solar wind blows an immense magnetic bubble, the heliosphere, in the local interstellar medium (mostly neutral gas) flowing by the Sun. Recent measurements by Voyager 2 across the termination shock, where the solar wind is slowed to subsonic speeds before entering the heliosheath, found that the shocked solar wind plasma contains only approximately 20 per cent of the energy released by the termination shock, whereas energetic particles above approximately 28 keV contain only approximately 10 per cent; approximately 70 per cent of the energy is unaccounted for, leading to speculation that the unmeasured pickup ions or energetic particles below 28 keV contain the missing energy. Here we report the detection and mapping of heliosheath energetic ( approximately 4-20 keV) neutral atoms produced by charge exchange of suprathermal ions with interstellar neutral atoms. The energetic neutral atoms come from a source approximately 60 degrees wide in longitude straddling the direction of the local interstellar medium. Their energy spectra resemble those of solar wind pickup ions, but with a knee at approximately 11 keV instead of approximately 4 keV, indicating that their parent ions are pickup ions energized by the termination shock. These termination-shock-energized pickup ions contain the missing approximately 70 per cent of the energy dissipated in the termination shock, and they dominate the pressure in the heliosheath.     

应用激光反射仪研究聚氧乙烯十二烷基醚溶液在硅片表面上的吸附解吸过程(英文)

将激光反射仪应用于溶液吸附上,考察了聚氧乙烯十二烷基醚--一种非离子表面活性剂溶液在硅片表面上的吸附解吸过程,结果表明其吸附过程极快,30s 达到稳定值,且解吸完全.其最大吸附量Г(mg·m-2)是2.45 mg·m-2.在临界表面相关浓度CSAC(0.045 5 mmol·L-1)以下的浓度范围内,吸附模型符合Langmuir模型.     

一种新型的电焊机节能装置

本文根据焊接变压器的基本原理,研究了一种交流弧焊机的节能装置。     

W1607俯斜沿空综采面的瓦斯治理及防灭火技术

新集二矿针对W1607俯斜沿空综采工作面瓦斯涌出的特点,分析了工作面上隅角的瓦斯来源,对综采工作面设施了合理配风、均压通风、本煤层瓦斯抽放、顶板走向钻孔抽放及顶板高抽巷抽放瓦斯的综合治理及防火措施,确保了高产高效俯斜沿空综采工作面的安全生产。     

基于驾驶员眼动分析的事故多发点改造方案评价方法研究

对事故多发点进行改造是减少事故的发生、增强交通安全的重要措施,其中增加标志标线等交通安全设施是常见的改造方式。由于驾驶行为是影响交通安全的重要因素,因此有必要从驾驶员角度对改造效进行评价。本文研究了某二级公路的事故多发点特点,在现场实验的基础上结合驾驶员眼动注视点的特征分析,分别从驾驶员注视特征、运营速度、改造前后的事故分析,综合评价事故多发点的改造效果,同时分析驾驶员负荷特征,为未来事故多发点的安全改造方案提出可行建议。     

蓄热式空间燃烧烤包器

在分析蓄热燃烧方法和现有蓄热式烤包器的基础上，结合莱钢炼钢厂钢包烘烤现状，研制开发了新的蓄热式空间燃烧烤包器。现场使用证明该烤包器具有节能、加热均匀和低污染排放等显著优点，具有广阔的应用前景。     

Activation in vitro of sequence-specific DNA binding by a human regulatory factor

The human heat-shock factor (HSF) regulates heat-shock genes in response to elevated temperature. When human cells are heated to 43 degrees C, HSF is modified post-translationally from a form that does not bind DNA to a form that binds to a specific sequence (the heat-shock element, HSE) found upstream of heat-shock genes. To investigate the transduction of the heat signal to HSF, and more generally, how mammalian cells respond at the molecular level to environmental stimuli, we have developed a cell-free system that exhibits heat-induced activation of human HSF in vitro. Comparison of HSF activation in vitro and in intact cells suggests that the response of human cells to heat shock involves at least two steps. First, an ATP-independent, heat-induced alteration of HSF allows it to bind the HSE; the temperature at which activation occurs in vitro implies that a human factor directly senses temperature. Second, HSF is phosphorylated. It is possible that similar multi-step activation mechanisms play a role in the response of eukaryotic cells to a variety of environmental stimuli, and that these mechanisms evolved to increase the range and flexibility of the response.