Comparison of CSC method and the B-net method for deducing smoothness condition

The first author of this paper established an approach to study the multivariate spline over arbitrary partition, and presented the so-called conformality method of smoothing cofactor (the CSC method). Farin introduced the B-net method which is suitable for studying the multivariate spline over simplex partitions. This paper indicates that the smoothness conditions obtained in terms of the B-net method can be derived by the CSC method for the spline spaces over simplex partitions, and the CSC method is more capable in some sense than the B-net method in studying the multivariate spline.     

固氮酶Fe-Mo辅因子空间构型模拟——分子力学在分子模型设计中的应用

在分子模型设计中交替使用分子图形学软件和分子力学优化计算,用计算机模拟固氮酶Fe-Mo辅因子空间构型,从而为进一步的理论研究提供了一个非实验方法的有效手段。     

Molybdenum cofactor biosynthesis and deficiency

The molybdenum cofactor (Moco) forms the active site of all molybdenum (Mo) enzymes, except nitrogenase. Mo enzymes catalyze important redox reactions in global metabolic cycles. Moco consists of Mo covalently bound to one or two dithiolates attached to a unique tricyclic pterin moiety commonly referred to as molybdopterin (MPT). Moco is synthesized by an ancient and conserved biosynthetic pathway that can be divided into four steps, according to the biosynthetic intermediates precursor Z (cyclic pyranopterin monophosphate), MPT and adenylated MPT. In a fifth step modifications such as attachment of nucleotides, sulfuration or bond formation between Mo and the protein result in different catalytic Mo centers. A defect in any of the steps of Moco biosynthesis results in the pleiotropic loss of all Mo enzyme activities. Human Moco deficiency is a hereditary metabolic disorder characterized by severe neurodegeneration resulting in early childhood death. Recently, a first substitution therapy was established. Received 17 June 2005; received after revision 18 August 2005; accepted 1 September 2005     

矿区扩展网的设计

本文提出矿区控制网扩展时,将新网按旧网原有的等级进行布设,并将新、旧网看作一个整体,统一进行平差,并推证了精度估算公式。这种方法在理论上是严密的,计算时规律性很强,便于计算机运算,并使新旧网联接处的精度提高20％左右。     

产生任意k阶余因式的原理和方法

提出了不定导纳矩阵任意k阶余因式的有向树拓扑表示式;给出了通过混合分割产生有向树多项式的分解定理.应用它们可以方便有效地求取任意k阶余因式的拓扑表示式.用其求全符号网络函数,可扩大计算机所能拓扑分析的网络规模.用其求部分符号网络函数,可使计算机所能分析的网络规模扩大到一般数值分析程序所能处理的阶数.     

STUDY ON A NEW NONIONIC MICRIOPARTICLE RETENTION SYSTEM

Microparticle retention system, developed lately, mainly consists of cationic polymers and anionic inorganic substances, such as Hydrocol system consisting of cationic polyacrylamide/modified bentonite and Compozil system[2] with cationic starch/anionic silica sol. The principle of electrostatic interaction has been adopted for these systems. Whereas if there are plentiful anionic trashes in systems, their efficiency will not embody primely. Although anionic trash catcher (ATC) could be adde…     

固氮酶催化作用机理及其化学模拟

固氮酶是某些微生物在常温常压下固氮成氨的主要催化剂,其催化机理和化学模拟是国际上长期致力研究的对象。尽管人们已经揭示了固氮酶催化活性中心——铁钼辅基（FeMo-co)MoFe7S9（R-高柠檬酸）的结构,然铡,有关FeMo-co生物合成的详细途径和其中包含的钼铁转移和利用;固氮酶在哪些活性位和按什么模式结合N2,C2H2、CO等多种底物或抑制剂;以及其中涉及的电子和质子传递过程等许多问题,至今尚有待解决。本文将综述这些问题的研究进展和厦门大学固氮组最近五年来的相关研究工作。     

The coordination and function of the redox centres of the membrane-bound nitrate reductases

Under anaerobic conditions and in the presence of nitrate, the facultative anaerobe Escherichia coli synthesises an electron-transport chain comprising a primary dehydrogenase and the terminal membrane-bound nitrate reductase A (NarGHI). This review focuses on recent advances obtained on the structure and function of the three protein subunits of membrane-bound nitrate reductases. We discuss a global architecture for the Mo-bisMGD-containing subunit (NarG) and a coordination model for the four [Fe–S] centres of the electron-transfer subunit (NarH) and for the two b-type haems of the anchor subunit NarI.     

肺炎克雷伯杆菌表达吡咯喹啉醌依赖性聚乙烯醇脱氢酶

聚乙烯醇脱氢酶（PVADH）是降解聚乙烯醇（PVA）的关键酶,大肠杆菌或毕赤酵母生产PVADH需额外添加辅酶吡咯喹啉醌（PQQ）才具活性。为了降低添加PQQ的成本,在PQQ天然生产菌肺炎克雷伯杆菌（Klebsiella pneumoniae）中表达全酶PQQ-PVADH。首先通过外源基因密码子优化实现PVADH的高效表达,PVADH酶活达到45 U/mL;进而通过辅酶再生提高PQQ产量,双质粒重组菌Kp（pvadh+pqq）的PVADH酶活达到68 U/mL;最后经发酵优化,PVADH酶活达到81 U/mL,为PQQ-PVADH的生产提供了另一种选择方案。