Clinical applications of chemiluminescence

This article reviews the clinical applications of chemiluminescence in routine testing and surveys the diverse applications of chemiluminescence in clinical research. In routine clinical testing, chemiluminescent labels (acridinium ester, acridinium sulfonamide) and detection reactions for peroxidase and alkaline phosphatase enzyme labels (luminol and adamantyl 1,2-dioxetane-based reactions, respectively) are widely used in immunoassay and nucleic acid probe assays (e.g. hybridization protection assay, Hybrid Capture^® assay). In clinical research the sensitivity, dynamic range and diversity of chemiluminescent assays has led to a vast range of applications, notably in protein and nucleic acid blotting, microarray-based assays, monitoring reactive oxygen species, and as detection reactions for substances separated by HPLC, capillary electrophoresis (CE), and flow-injection analysis.     

Diastereoselective hydroformylation of 2-substituted allylic o-DPPB-esters-on the origin of 1,2-asymmetric induction

2-Substituted secondary alcohol o-DPPB esters (o-DPPB=ortho-diphenylphosphanylbenzoyl) have been prepared and their o-DPPB-directed diastereoselective hydroformylation examined. It was found that the diastereoselectivity increased as a function of the steric demand of the substituents both at the stereogenic center and in the alkene 2-position. Hydrolytic cleavage of the o-DPPB group afforded-via the lactols 29-the corresponding lactones 30, the relative configurations of the vicinal stereogenic centers of which were ascertainable by 2D-NOESY spectroscopy. In addition, a crystal structure analysis of the hydroformylation product 2 d provided further confirmation of the relative configuration. Replacement of the ester carbonyl group of the o-DPPB by a methylene unit resulted in significantly worse diastereoselectivity in the course of the hydroformylation (34-->35), which indicates a decisive role for the ester carbonyl function. All the experimental observations were combined in a model of the origin of the 1,2-asymmetric induction during the title reaction. The key feature is the consideration of diastereomeric trigonal-bipyramidal rhodium-hydrido-olefin complexes I and II, capable on the basis of the Hammond postulate of acting as good models for the transition states of the selectivity-determining hydrometalation step. Investigation of these complexes by force-field methods indicated good correlation between theoretically predicted and experimentally determined diastereoselectivities.     

聚4-重氮基苯乙烯与聚苯乙烯磺酸钠的自组装

1991年Ｄｅｃｈｅｒ等将带相反电荷的聚电解质 ,于水溶液中交替沉积在片基上 ,制备了多层超薄膜[1] ,这种制膜方法现称为静电自组装 .它操作简单 ,无需专用设备 ;一般在水体系进行 ,对环境友好 ;静电力比范德华力强 ,使它比ＬＢ膜稳定 ,所以近年来有很大发展[2 ] .现在自组装成膜驱动力已从静电力扩展到氢键力、电荷转移相互作用、疏水相互作用等 ,用于组装的组分也从聚电解质扩展到多官能团小分子、胶体粒子、无机纳米颗粒 ,ＤＮＡ、蛋白质等生物大分子等[3～ 11] .虽然自组装膜比ＬＢ膜稳定 ,但它也不耐极性溶剂、电解质水溶液等侵蚀 .如…     

四氢呋喃-水-乙醇三元溶液体系制备高合金化Pt-Ru/CMK-3催化剂

提出了在四氢呋喃(THF)、H2O和乙醇三元体系中用一般的化学还原法在室温下制备高合金化Pt-Ru/CMK-3催化剂的新方法. 与在纯水中制得的商品化ETEK催化剂相比, 其Pt-Ru粒子的合金化程度高、平均粒径较小且相对结晶度低, 因此, 该催化剂对甲醇氧化的电催化活性远高于在纯水中制得的Pt-Ru催化剂. 高合金化程度的原因是H2PtCl6和RuCl3在THF、H2O和乙醇三元溶液体系中的起始还原电位相近. 此外, CMK-3以其规整的二维有序孔道结构, 为直接甲醇燃烧电池(DMFC)中电子和物质的传输提供了方便的路径, 其巨大的比表面积也为Pt-Ru 纳米粒子的均匀分散提供了良好的载体.     

Characterization of Titania/Silica Gel by Means of Low-Pressure Nitrogen Adsorption

Adsorbents synthesized by grafting of titania onto mesoporous silica gel surfaces at different temperatures were studied by means of nitrogen adsorption–desorption and water desorption. The pore size distribution f(R_p) of titania/silica gel depends on the titania concentration (C_TiO2) and the temperature of titania synthesis. Nonuniformity of TiO₂ phase is maximal at a low C_TiO2 value (3.2 wt.% anatase deposited at 473 K), and two peaks of the fractal dimension distribution f(D) are observed at such a concentration of titania, but at larger C_TiO2 values, only one f(D) peak is seen. More ordered filling of pores and adsorption sites by nitrogen, reflecting in the shape of adsorption energy distributions f(E) at different pressures of adsorbate, is observed for adsorbent with titania (rutile+anatase) grafted on silica gel at a higher temperature (673 K).     

Coupling Cloud Point Extraction to Instrumental Detection Systems for Metal Analysis

The purpose of this article is to review and evaluate cloud point extraction of metals and its coupling to different contemporary instrumental methods of analysis. This review covers a selection of the literature published on this topic over the period mainly between 1997 and September 2005 (consisting of 50 publications). The current state of the art for CPE concerning metals and metal chelates is presented with special emphasis on the hyphenation of this interesting extraction/preconcentration approach mediated by surfactants to spectrophotometry, atomic spectroscopy and separation techniques. We present contemporary CPE developments concerning metal speciation and determination and their application to different environmental, clinical, geological and food samples. Strategies for method development as well as future perspectives are also covered.     

Molecular potential-energy surfaces for chemical reaction dynamics

This paper reviews the construction of molecular potential-energy surfaces by an interpolation method which has been developed over the last several years. The method uses ab initio quantum chemistry calculations of the molecular electronic energy in an automated procedure to construct global potential- energy surfaces which can be used to simulate chemical reactions with either classical or quantum dynamics. The methodology is explained and several applications are presented to illustrate the approach. Received: 22 February 2002 / Accepted: 2 May 2002 / Published online: 6 November 2002 Correspondence to: M. A. Collins e-mail: collins@rsc.anu.edu.au Acknowledgements. The methods described in this overview are the result of collaborations with former members of my group, in particular with Josef Ischtwan, Meredith Jordon, Keiran Thompson and Ryan Bettens. I am also indebted for inspiration gained from many discussions with my colleagues Leo Radom and Donghui Zhang (National University of Singapore). This work has been supported by the Supercomputer Facility of the Australian National University and the Australian Partnership for Advanced Computing.     

Variational transition state theory without the minimum-energy path

In this paper we propose a method for carrying out variational transition state theory calculations without first obtaining a converged minimum-energy path (MEP). We illustrate the method in two ways, first of all by employing an unconverged MEP and secondly by using a dynamically optimized distinguished reaction path. Preliminary tests of the algorithm for the reactions OH+H₂→H₂O+H and C₂H₅→C₂H₄+H are very encouraging. Received: 22 January 1997 / Accepted: 11 March 1997     

Er:Yb:KGW激光晶体生长及缺陷研究

采用顶部籽晶(TSSG)法生长ErYbKGW晶体.通过研究助熔剂的种类、组成与溶质的比例关系对晶体生长的影响,设计了合理的工艺条件转速30～40 r·min-1;拉速1～2 mm·d-1;降温生长速率0.05 ℃·h-1;降温速率15 ℃·h-1;生长周期15～20 d.通过对晶体缺陷的观察分析认为,晶体裂缝及包裹物等缺陷与生长工艺条件密切相关,应尽量减少生长过程中的温度、浓度及生长速度的波动,保持晶体的稳态生长.     

Response Characteristics of Arsenic-Sensitive Bioreporters Expressing the gfp Reporter Gene

This paper describes the development of an analytical technique for arsenic analyses that is based on genetically-modified bioreporter bacteria bearing a gene encoding for the production of a green fluorescent protein (gfp). Upon exposure to arsenic (in the aqueous form of arsenite), the bioreporter production of the fluorescent reporter molecule is monitored spectroscopically. We compared the response measured as a function of time and concentration by steady-state fluorimetry (SSF) to that measured by epi-fluorescent microscopy (EFM). SSF is a bulk technique; as such it inherently yields less information, whereas EFM monitors the response of many individual cells simultaneously and data can be processed in terms of population averages or subpopulations. For the bioreporter strain used here, as well as for the literature we cite, the two techniques exhibit similar performance characteristics. The results presented here show that the EFM technique can compete with SSF and shows substantially more promise for future improvement; it is a matter of research interest to develop optimized methods of EFM image analysis and statistical data treatment. EFM is a conduit for understanding the dynamics of individual cell response vs. population response, which is not only a matter of research interest, but is also promising in the practical terms of developing micro-scale analysis.