THE STRUCTURAL BASIS OF THE POOR FIBRIN SPECIFICITY OF UROKINASE(Ⅰ)——KNOWLEDGE-BASED PREDICTION OF KRINGLE STRUCTURES OF UROKINASE AND ITS RELATED PROTEINS

The Kringle-1 structure of plasminogen (PGK-1), the Kringle-2 structure of tissue plasminogen activator (PAK-2) and the Kringle structure of prourokinase (UKK) has been modeled on the basis of the three-dimensional structure of Kringle-1 of prothrombin (PTK-1) at 2.8 resolution. The predicted three-dimensional structure of these Kringles shows that the binding site of PGK-1 is characterized by an apparent dipolar site, the polar parts of which are separated by a hydrophobic region. PAK-2 possesses the anionic center but has not a cationic binding center which might be provided by a guanidinium group from Arg-69 located adjacent to the Arg-71 position. UKK possesses neither the anionic binding center nor the cationic center which are probably the main reason for the poor fibrin specificity of urokinase.     

甲醇气相羰基化制备乙酸的钴催化剂(YSCo)的研究

甲醇气相羰基化制备乙酸的钴催化剂（ＹＳＣｏ）的研究潘平来，柳忠阳，黄茂开，袁国卿（中国科学院化学研究所，北京１０００８０）关键词甲醇，羰基化，乙酸，钴催化剂通过甲醇羰基化制备乙酸是目前乙酸工业最先进的技术路线．该法与乙烯和乙醇氧化法相比较，无论从原料...     

量子点传感器测定水中微量银离子

选择铋试剂Ⅱ作为硫化镉(cds)量子点的修饰剂,合成了表面修饰的量子点,利用其有效官能团与银离子作用,导致修饰的量子点的荧光增强作用,建立了测定银离子的方法,开发了新型的银离子的传感器。结果表明,对水中银离子测定的线性范围为0.01~5.0μmol.L-1,相关系数为0.999 3,检测限达到1.6 nmol.L-1,对实际水样的分析获得了较满意的结果。     

Interface states in Al_2O_3/AlGaN/GaN metal-oxide-semiconductor structure by frequency dependent conductance technique

Frequency dependent conductance measurements are implemented to investigate the interface states in Al2O3/AlGaN/GaN metal-oxide-semiconductor(MOS) structures. Two types of device structures, namely, the recessed gate structure(RGS) and the normal gate structure(NGS), are studied in the experiment. Interface trap parameters including trap density Dit, trap time constant τit, and trap state energy ETin both devices have been determined. Furthermore,the obtained results demonstrate that the gate recess process can induce extra traps with shallower energy levels at the Al2O3/AlGaN interface due to the damage on the surface of the AlGaN barrier layer resulting from reactive ion etching(RIE).     

医用硬性内窥镜畸变的评定基础和方法

建立医用硬性内窥镜畸变的评定基础和方法,用视轴对称的球面Z视场为模型来模拟体腔凹面特征,以建立内窥镜物像共轭的分析基础;运用光学原理并结合ISO9039:1994“光学和光学仪器光学系统质量评价———畸变的测定”的定义原则,并根据理论畸变的临床要求确定畸变定义;采用主光线追迹原理推导不同球面Z形状的畸变换算通式。创立了医用硬性内窥镜以单位相对畸变表述的定义和表达式,并导出变换视场面的畸变换算通用公式和测试方法。本文建立的畸变评定基础和方法适用于医用硬性内窥镜的标准应用。     

A corresponding-state approach to quark-cluster matter

The state of super-dense matter is essential for us to understand the nature of pulsars; however, non- perturbative quantum chromodynamics makes it very difficult to make direct calculations of the state of cold matter at realistic baryon number densities inside compact stars. Nevertheless, from an observational point of view, it is conjectured that pulsars could be made up of quark clusters since the strong coupling between quarks might render the quarks to be grouped in clusters. In this paper, we attempt to find an equation of state of condensed quark-cluster matter in a phenomenological way. Supposing that the quark-clusters could be analogized to inert gases, we apply here the corresponding-state approach to derive the equation of state of quark-cluster matter, as was similarly demonstrated for nuclear and neutron-star matter in the 1970s. According to the calculations that we have presented, the quark-cluster stars, which are composed of quark-cluster matter, could have a high maximum mass that is consistent with observations and, in turn, further observations of pulsar mass could also place a constraint on the properties of quark-cluster matter. We will also briefly discuss the melting heat during the solid-liquid phase conversion and its related astrophysical consequences.     

基于蛋白构象变化研究pH值对茜素红与牛血清白蛋白相互作用的影响

利用光谱法和分子对接技术研究了不同pH值对牛血清白蛋白(BSA)与茜素红(ARS)键合作用的影响。pH值为4.0的酸性环境引起BSA天然紧缩构象逐渐发生去折叠,BSA的ⅡA区疏水空腔的展开降低了其与ARS的相互作用,键合常数Kb仅为3.39×104L·mol-1。而pH值大于等电点(pI 4.8)或呈现中性时,两者的键合作用增强,Kb增至3.16×106L·mol-1(pH 7.0)。而且,由于氢键和范德华力的键合作用力较强,BSA和ARS的相互作用受表面电荷影响较小,与理论模拟对接结果相吻合。     

长链烷基胺氢卤酸盐的热致相变

差示扫描量热法（ＤＳＣ）结果表明，烷基胺氢卤酸盐化合物的相变温度与化合物烷基链链长之间存在明显的规律性，固－固结构相变的主相变峰温随烷基链链长的递增而升高，其逆相变过程表现出明显的热滞后现象；而熔融相变温度则随烷基链链长的递增而降低；实验结果还表明，试样的陈化放置过程以及结晶过程中所用的溶剂对化合物的热致相变历程都有明显的影响。