Molecular Replacement Studies of Cucurmosin from Cucurbita Moschata:Structure Homology with Trichosanthin

1 INTRODUCTION Many plants contain proteins that are capable of inactivating ribosomes and therefore are called ribosome-inactivating proteins or RIPs[1]. RIPs are RNA N-glycosidases that inactivate ribosomes through a site-specific deadenylation of the large ribosomal RNA[2, 3]. RIPs are also capable of inactivating many nonribosomal nucleic acid substrates and can be considered as polynucleotide: adenosine glycosidases[4～6]. There are two types of RIPs: type I, single chain pr…     

Electrochemical synthesis of 1,2,3,4,4,5,6-substituted 1,4-dihydropyridines

It has been shown that chemical oxidation of the methyl ester of 3,4,5-trimethoxycarbonyl-1,2,6-trimethyl-1,4-dihydropyridine to the pyridinium salt, requiring forcing experimental conditions, may be replaced by electrochemical oxidation. On electrochemical reduction of 3,4,5-trimethoxycarbonyl-1,2,6-trimethylpyridinium perchlorate in the presence of alkylating agents 1,2,3,4,4,5,6-substituted 1,4-dihydropyridines are obtained. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 226–237, February, 2007.     

铝与溴代二甲氨基苯基荧光酮的多元配合物的光度研究

本文研究了在表面活性剂存在性，铝与溴代二甲氨基苯基荧光酮的显色反应。在弱酸性介质中，Ａｌ＾３＋ＢＤＭＡＦ－ＣＴＭＡＢ三元配合物在水浴加热至７０℃－８０℃时形成，其最大吸收波长为５７７ｎｍ，Ａｌ＾３＋：ＢＤＭＡＦ＝１：２，表观摩尔吸光系数为１．３４×１０＾５Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，表观稳定常数为７．４×１０＾５。在ＰＨ９．５－１０．５的氨性缓冲介质中，Ａｌ＾３＋－Ｆ＾－－ＢＤＭＡＦ－非离子表面     

研磨法合成1,2,3,6-四氢嘧啶-2-酮衍生物

以NH₂SO₃H为催化剂, 室温无溶剂条件下, 研磨芳醛、β-酮酸酯和尿素合成了一系列1,2,3,6-四氢嘧啶-2-酮衍生物. 该方法具有反应条件温和、操作简便、环境友好、产率高等优点.     

信息型常见毒物质谱用户库的建立及其在毒物快速筛选上的应用研究

质谱定性是目前世界上最通用的定性分析方法之一,在法庭科学领域毒物分析实践中,质谱一直是对未知样品进行药毒物筛选检测的利器.     

催化动力学极谱法测定痕量钼

在稀Ｈ２ＳＯ４介质中，钼（Ⅵ）对硫酸联氨还原乙基橙的反应有强烈的催化作用。建立了催化动力学极谱法测定痕量钼的新体系，方法线性范围为２０－３００ｎｇ／ｍＬ，检出限为３．５４ｎｇ／ｍＬ。方法应用于尿中中钼的测定，结果满意。     

A new Monte Carlo simulation for two models of self-avoiding lattice trees in two dimensions

By means of a new Monte Carlo sampling of a grand canonical ensemble, we verify universality for the critical exponents and of two models of lattice trees constrained to be self-avoiding on sites or on bonds. The attrition constants are also obtained. This algorithm, a generalization of that recently proposed by Berretti and Sokal for random walks, appears to optimize the critical slowing down in the scaling region. Systematic and statistical errors are carefully estimated.     

On some variational approximations in two-dimensional classical lattice systems

A new derivation is presented of some variational approximations for classical lattice systems that belong to the class of cluster-variation methods, among them the well-known Bethe-Peierls and Kramers-Wannier approximations. The limiting behavior of a hierarchical sequence of cluster-variation approximations, the so-calledC hierarchy, is discussed. It is shown that this hierarchy provides a monotonically decreasing sequence of upper boundsf _n on the free energy per lattice sitef and thatf _n f asn . Our results are based on extension theorems for states given on subsets of the lattice, which might be of some independent interest, and on an application of transfer matrix concepts to the variational characterization of translation-invariant equilibrium states.     

偏最小二乘光度法同时测定多种酚的研究及应用

利用Ｃｕ（Ⅱ）吡啶能与酚形成稳定的三元配合物的特点，研究了Ｃｕ（Ⅱ）－吡啶－酚三元显色新体系，并以偏最小二乘法建立模型预测，同时测定了模拟水样和环境水样中的对苯二酚、间苯二酚、邻苯三酚和对硝基苯酚，取得满意效果。