Structures and electrochemical characteristics of several kinds of alloys

The structures and the electrochemical characteristics of La_0.7−x Ce_xMg_0.3Ni_2.8Co_0.5 (x = 0.1–0.5) alloy, Ti_0.25−x Zr_xV_0.35Cr_0.1Ni_0.3 (x = 0.05–0.15) alloy and AB_3<x<5-type alloy, which are the representative examples of AB₃-type alloy, solid solution alloy and non-AB₅-type alloy, respectively, have been investigated, and the performances of MH-Ni battery in which AB_3<x<5 type alloy is used as the negative electrode material are examined at relatively low temperature.     

Capillary gas chromatography of pesticide residues in foods: Application of a split/splitless inlet system

Residue mixtures of pesticides in foods which were difficult to separate by packed-column gas chromatography were determined by capillary gas chromatography and electron capture detection. Manual injections of sample and reference standard were made with a 10 μL syringe on a septum-enclosed, split/ splitless inlet system. Optimal peak height repeatability (± 3%( was achieved with three-μL injections which were made within time periods of four hours or less. The average linearity coefficient (slope( obtained for detector response as a function of solution concentration was 1.1.     

Nucleotide/Protein Interaction: Energetic and Structural Features of Na,K-ATPase

Microcalorimetric titrations allow to recognize and investigate high-affinity ligand binding to Na,K-ATPase. Titrations with the cardiac glycoside Ouabain, which acts as a specific inhibitor of the enzyme, have provided not only the thermodynamic parameters of high-affinity binding with a stoichiometric coefficient of about 0.6 but also evidence for low-affinity binding to the lipid. The marked enthalpic contribution of -95 kJ mol^-1 at 298.2 K is partially compensated by a large negative entropy change, attributed to an increased interaction between water and the protein. The calorimetric ADP and ATP titrations at 298.2 K are indicative of high-affinity nucleotide binding either in 3 mM NaCl, 3 mM MgCl₂ or at high ionic strength such as 120 mM choline chloride. However, no binding is detected in the buffer solution alone at low ionic strength. The affinities for ADP and ATP are similar, around 10⁶ M^-1 and the stoichiometric coefficients are close to that of Ouabain binding. The exothermic binding of ADP is characterized by a ΔH and ΔS value of -65 kJ mol^-1 and -100 J mol^-1 K^-1, respectively. TheΔH value for ATP binding is larger than for ADP and is compensated by a larger, unfavorable ΔS value. This leads to an enthalpy/entropy compensation, which could express that H-bond formation represents the major type of interaction. As for Ouabain, the negative ΔS values that are also characteristic of nucleotide binding can indicate an increase of solvate interaction with the protein due to a conformational transition occurring subsequent to the binding process. The resulting binding constants are discussed with regard to the results of other studies employing different techniques. A molecular interaction model for nucleotide binding is suggested. This revised version was published online in July 2006 with corrections to the Cover Date.     

Ligand-protein docking using a quantum stochastic tunneling optimization method

A novel hybrid optimization method called quantum stochastic tunneling has been recently introduced. Here, we report its implementation within a new docking program called EasyDock and a validation with the CCDC/Astex data set of ligand-protein complexes using the PLP score to represent the ligand-protein potential energy surface and ScreenScore to score the ligand-protein binding energies. When taking the top energy-ranked ligand binding mode pose, we were able to predict the correct crystallographic ligand binding mode in up to 75% of the cases. By using this novel optimization method run times for typical docking simulations are significantly shortened.     

超临界流体萃取仪器的研制

本文报道了以国产原配件为基础，成功地研制了分析规模的超临界流体萃取仪器、并对仪器性能进行了全面考察，仪器性能稳定，重现性良好（ＲＳＤ＜３．１％），定量线性关系可靠，可满足定量萃取的要求。     

Characteristics and production of thermostable α-amylase

Thermostable α-amylases have application in a variety of industrial processes and enzymes from a substantial number of thermophilic bacteria and fungi have been screened and characterized to varying degrees. The characteristics of these enzymes are summarized in this review. The genetics of α-amylase production inBacillus subtilis is reviewed and classical and recombinant DNA approaches to increasing α-amylase production are discussed.     

高效毛细管电泳前沿分析法研究酸性药物那格列奈与人血浆白蛋白的结合

用高效毛细管电泳前沿分析法研究了酸性药物那格列奈与人血浆白蛋白的结合常数、结合位点和结合率。使用未涂层的毛细管柱 (4 0cm× 5 0 μmi.d .;有效柱长 32cm) ,磷酸盐缓冲溶液 (pH 7.4 ,离子强度0 .17)为背景溶液 ,在紫外检测波长 2 14nm、运行电压 18kV和重力进样 10 0s的条件下 ,利用那格列奈谱峰的平台高度和游离药物浓度的良好线性关系 (r>0 .999,n =6 ) ,测定了那格列奈的游离药物浓度。固定药物浓度 (2 0 0 μmol L ,2 5 0 μmol L) ,考察不同的蛋白质浓度对结合的影响 ;固定蛋白质浓度 (10 0 μmol L) ,考察不同的药物浓度对结合的影响。实验数据采用非线性拟和程序进行处理 ,得到了那格列奈的蛋白质结合参数。高效毛细管电泳前沿分析法测定的数据重现性良好 (RSD <2 .5 % ,n =3) ,在药代动力学和药效学研究方面具有简便、准确的优点。     

Synthesis and antitumor activity of DNA binding cationic porphyrin-platinum(II) complexes

A new series of DNA binding 5,10,15-tri(N-methyl-4-pyridiniumyl)porphyrin (TrisMPyP)-platinum(II) conjugates was synthesized, in which different spacer ligands were used for appropriate coordination to platinum(II) complexes. Compound 9b exhibited in vivo antitumor activity (T/C%, 294) superior to cisplatin (T/C%, 184) against the leukemia L1210 cell line.     

用XPS研究我国一些煤中有机硫的存在形态

本文用电子能谱（xps）方法研究了我国九个不同牌号煤中有机硫的存在形态，并得到这些煤中各种不同形态硫的结合能数据。根据Lindberg等人所做模型化合物结果，给出了这些煤中硫元素结构能的化学归属。各种煤中硫的存在形态是不同的，有硫醇、硫醚、双硫醚、硫杂环、硫桥和取代基上的硫等。这一研究结果为今后研究煤的分子结构及脱硫方法提供了重要的科学依据。     

壳聚糖／聚丙烯酸聚电解质复合物膜对水／有机液体系的渗透汽化性能

以壳聚糖和聚丙烯酸为原料制备了聚电解质复合物膜，并对其分离水／乙醇体系的渗透汽化特性和浓度，温度，化学组成等因素的影响进行了研究，发现后处理方法对复合物膜的分离性能影响很大。同时对其它水／有机液体系，该膜也具备优异的分离性能。