PURIFICATION AND CHARACTERIZATION OF A KINASE SPECIFIC FOR THE SERINE-RICH AND ARGININE-RICH PRE-MESSENGER-RNA SPLICING FACTORS

Members of the SR family of pre-mRNA splicing factors are phosphoproteins that share a phosphoepitope specifically recognized by monoclonal antibody (mAb) 104. Recent studies have indicated that phosphorylation may regulate the activity and the intracellular localization of these splicing factors. Here, we report the purification and kinetic properties of SR protein kinase 1 (SRPK1), a kinase specific for SR family members. We demonstrate that the kinase specifically recognizes the SR domain, which contains serine/arginine repeats. Previous studies have shown that dephosphorylated SR proteins did not react with mAb 104 and migrated faster in SDS gels than SR proteins from mammalian cells. We show that SRPK1 restores both mobility and mAB 104 reactivity to a SR protein SF2/ASF (splicing factor 2/alternative splicing factor) produced in bacteria, suggesting that SRPK1 is responsible for the generation of the mAb 104-specific phosphoepitope in vivo. Finally, we have correlated the effects of mutagenesis in the SR domain of SF2/ASF on splicing with those on phosphorylation of the protein by SRPK1, suggesting that phosphorylation of SR proteins is required for splicing.

STUDIES ON THE PURIFICATION AND RECLAMATION OF WASTE-WATER FROM A MEDIUM-SIZED CITY BY AN INTEGRATED BIOLOGICAL POND SYSTEM

The feasibility of an inexpensive wastewater treatment system is evaluated in this study. An integrated biological pond system was operated for more than 3 years to purify the wastewater from a medium-sized city, Central China. The experiment was conducted in 3 phases with different treatment combinations for testing their purification efficiencies. The pond system was divided into 3 functional regions: influent purification, effluent upgrading and multi-utilization. These regions were further divided into several zones and subzones. Various kinds of aquatic organisms, including macrophytes, algae, microorganisms and zooplankton, were effectively cooperating in the wastewater treatment in this system. The system attained high reductions of BOD5, COD, TSS, TN, TP and other pollutants. The purification efficiencies of this system were higher than those of most traditional oxidation ponds or ordinary macrophyte ponds. The mutagenic effect and numbers of bacteria and viruses declined significantly during the process of purification. After the wastewater flowed through the upgrading zone, the concentrations of pollutants and algae evidently decreased. Plant harvesting did not yield dramatic effects on reductions of the main pollutants, though it did significantly affect the biomass productivity of the macrophytes. The effluent from this system could be utilized in irrigation and aquaculture. Some aquatic products were harvested from this system and some biomass was utilized for food, fertilizer, fodder and some other uses. The wastewater was reclaimed for various purposes.

Purification of single-walled carbon nanotubes synthesized by the catalytic decomposition of hydrocarbons

A procedure for purifying single-walled carbon nanotubes (SWNTs) synthesized by the catalytic decomposition of hydrocarbons has been developed. Based on the results from SEM observations, EDS analysis and Raman measurements, it was found that amorphous carbon, catalyst particles, vapor-grown carbon nanofibers and multi-walled carbon nanotubes were removed from the ropes of SWNTs without damaging the SWNT bundles, and a 40% yield of the SWNTs with a purity of about 95% was achieved after purification. (C) 2000 Elsevier Science Ltd. All rights reserved.

The new exploration for proton-implanted silicon: the conversion of a surface-region-purification-induced p-n junction into a p-i-n electrical structure approaching silicon on insulator

A surface-region-purification-induced p-n junction, a puzzle discovered at Brookhaven National Laboratory, in a silicon-on-defect-layer (SODL) material has been explored by carrying out various annealing conditions and subsequent measurements on electrical properties. The origin of the pn junction has been experimentally investigated. Furthermore, the p-n junction has been transformed into a p-i-n electrical structure by adding a high temperature annealing process to the previously used SODL procedure, making the SODL material approach silicon on insulator (SOI). The control of the initial oxygen amount in the silicon material is suggested to be critical for the experimental results.

基于PAR的高可信装备保障算法推演

算法被誉为计算的“灵魂”（spirit of computing），算法程序的可靠性和正确性对软件系统的可信度起着至关重要的作用。动态规划、贪心、分支限界等传统的算法设计策略缺乏有效的选择标准，一些算法形式化开发方法和工具的应用水平和范围也很有限，因此算法的可靠性已成为高可信软件系统的一个主要瓶颈。 作为军事运筹学的一个重要分支，装备保障计算主要研究军事活动中装备领域的决策优化问题，保障计算软件特别是算法的可靠性在很大程度上决定了装备保障的效率乃至军事行动的成败。利用形式化软件工程的研究成果、特别是引入算法程序的形式化开发方法，对我军通用装备保障领域中的大量算法类问题进行有效求解，有利于优化保障结构、统筹保障资源、整合保障力量、提高保障时效，促进装备整体战斗力水平的提升。 本文以高可信软件开发方法PAR为基础，面向装备保障计算的领域需求，提出了一类离散最优化问题（discrete optimization problem, DOP）的结构模型和算法推演技术，并成功推演了一系列典型的装备保障算法。本论文的主要创新性贡献如下： （1）定义了DOP的结构模型，提出了基于单点结构（Singleton）的问题分划递推策略，进而通过PAR算法推演生成问题的高效求解算法，涵盖了多种传统算法设计策略，显著提高了算法程序设计的机械化水平。 （2）提出了描述DOP分划递推过程的问题简约图（problem reduction graph, PRG）模型，并针对典型DOP结构推演得到了一组PRG构造算法模式，其中每个算法模式都涵盖了满足特定代数结构性质的一大类具体问题。 （3）阐述了PAR算法推演的范畴模型，为算法设计和重用提供了抽象而有效的方法指导。 （4）对我军通用装备保障领域具有代表性的48个问题进行了形式化的算法推演，构建了领域算法库。 （5）在PAR平台的基础上设计了装备保障算法开发平台的原型COPALM，支持DOP算法推演和重用，进而提高了相关应用软件的开发效率。

基于PAR的算法形式化开发

形式化方法是构建可信软件的重要途径.基于对算法问题的分析,针对形式化方法PAR开发算法的特征,刻划了问题分划、递推关系构造方面的规律.从一类问题的形式化功能规约出发,可机械地完成问题的分划及规约的变换,自然地揭示出求解问题的算法思想,在相关工具的支持下自动生成算法程序.研究结果将算法设计中尽可能多的创造性劳动转化为非创造性劳动,降低了形式化求解算法问题的难度,提高了算法程序的可靠性和形式化开发效率.

PAR方法和循环不变式的范畴语义

范畴论对理解程序规约及程序设计和正确性证明十分有用.PAR方法则是建立在严格的数学基础之上的一种统一的算法程序设计方法.循环不变式在循环算法程序的设计中至关重要.使用格理论和范畴论作为工具对PAR方法建立一个理论框架,并对其用范畴论的概念加以解释,从而使得PAR有更强的理论基础.在此基础上引入不动点原理深入刻划循环不变式的含义,循环不变式可以表示为谓词泛函的最小不动点,并从范畴论的角度解释该过程.

Phosphoproteome analysis of mouse liver using immobilized metal affinity purification and linear ion trap mass spectrometry

Since protein phosphorylation is a dominant mechanism of information transfer in cells, there is a great need for methods capable of accurately elucidating sites of phosphorylation. In recent years mass spectrometry has become an increasingly viable alternative to more traditional methods of phosphorylation analysis. The present study used immobilized metal affinity chromatography (IMAC coupled with a linear ion trap mass spectrometer to analyze phosphorylated proteins in mouse liver. A total of 26 peptide sequences defining 26 sites of phosphorylation were determined. Although this number of identified phosphoproteins is not large, the approach is still of interest because a series of conservative criteria were adopted in data analysis. We note that, although the binding of non-phosphorylated peptides to the IMAC column was apparent, the improvements in high-speed scanning and quality of MS/MS spectra provided by the linear ion trap contributed to the phosphoprotein identification. Further analysis demonstrated that MS/MS/MS analysis was necessary to exclude the false-positive matches resulting from the MS/MS experiments, especially for multiphosphorylated peptides. The use of the linear ion trap considerably enabled exploitation of nanoflow-HPLC/MS/MS, and in addition MS/MS/MS has great potential in phosphoproteome research of relatively complex samples. Copyright (C) 2004 John Wiley Sons, Ltd.

Affinity membrane chromatography for the analysis and purification of proteins

Affinity chromatography is unique among separation methods as it is the only technique that permits the purification of proteins based on biological functions rather than individual physical or chemical properties. The high specificity of affinity chromatography is due to the strong interaction between the ligand and the proteins of interest. Membrane separation allows the processing of a large amount of sample in a relatively short time owing to its structure, which provides a system with rapid reaction kinetics. The integration of membrane and affinity chromatography provides a number of advantages over traditional affinity chromatography with porous-bead packed columns, especially with regard to time and recovery of activity. This review gives detailed descriptions of materials used as membrane substrates, preparation of basic membranes, coupling of affinity ligands to membrane supports, and categories of affinity membrane cartridges. It also summarizes the applications of cellulose/glycidyl methacrylate composite membranes for proteins separation developed in our laboratory. (C) 2001 Elsevier Science B.V. All rights reserved.

Expression, purification and spectral characterization of p21(Waf1/Cip1)

p21(Waf1/Cip1), best known as a broad-specificity inhibitor of cyclin/cyclin-dependent kinase complexes, can interact with various target proteins, and this ability relies on its structural plasticity. Therefore, studies on the structural properties of p(21) are very important to understand its structure-function relationship. However, detailed studies on its secondary structure and biophysical properties have been comparatively sparse. A human p(21) gene was cloned into the temperature expression vector pBV220 and transformed into Escherichia coli strain JM109.