耗散系统的准热力学模型

以具有自治系统一般形式的运动方程及其相应的Fokker-Planck方程为出发点,确立了一种适应面比较广的耗散系统的准热力学模型.定义了与驱动项f相共轭的函数X,取代作为上述运动方程的自田变量x(x可代表某种输出或化学反应的产物).以状态参量f,X,C(C为控制参量)对照参量p,V,T,得到一系列涉及准热力学函数及其导数的基本关系式,它们与传统热力学是一一对应的,最后给出一个应用范例. 关键词：     

Energy and Momentum Densities of Cosmological Models,with Equation of State <Emphasis Type="Italic">ρ</Emphasis>=<Emphasis Type="Italic">μ</Emphasis>, in General Relativity and Teleparallel Gravity

We calculated the energy and momentum densities of stiff fluid solutions, using Einstein, Bergmann–Thomson and Landau–Lifshitz energy-momentum complexes, in both general relativity and teleparallel gravity. In our analysis we get different results comparing the aforementioned complexes with each other when calculated in the same gravitational theory, either this is in general relativity and teleparallel gravity. However, interestingly enough, each complex’s value is the same either in general relativity or teleparallel gravity. Our results sustain that (i) general relativity or teleparallel gravity are equivalent theories (ii) different energy-momentum complexes do not provide the same energy and momentum densities neither in general relativity nor in teleparallel gravity. In the context of the theory of teleparallel gravity, the vector and axial-vector parts of the torsion are obtained. We show that the axial-vector torsion vanishes for the space-time under study.     

Radioprotective and Antitumor Activity of Some Novel Amino Acids and Imidazoles Containing Thieno[2,3-d]pyrimidine Moiety

A variety of novel thieno[2,3-d]pyrimidine derivatives, comprising amino acids 3a–l, imidazothieno-pyrimidines 4A, 4b–h, and 7, were obtained via the reaction of 4-chloro-5,6-dimethylthieno[2,3-d]pyrimidine 1 with a variety of reagents. The structures of these compounds were confirmed by microanalysis, IR, ¹H NMR, and mass spectrometry. Some of the obtained compounds showed promising radioprotective and antitumor activities.     

Synthesis of certain 2-substituted-1H-benzimidazole derivatives as antimicrobial and cytotoxic agents

A series of 2-substituted-1H-benzimidazole derivatives were synthesized and evaluated for antimicrobial, antifungal and cytotoxic activities. The results showed that all tested compounds showed potent antimicrobial activity against some species of Gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli, Salmonella typhi) and fungi (Candida albicans) with minimum inhibitory concentrations (MICs) lower than 0.016 μg/mL. In contrast, all tested compounds were inactive against Staphylococcus aureus (Gram-positive bacterium). The final targets were also tested for their antitumor activity in vitro on cervical carcinoma (HeLa) cell line. Eight of the test compounds displayed more potent cytotoxic effect than doxorubicin at nanomolar concentrations. Compounds 2c and 3c exerted the strongest cytoyoxic effect with IC(50) 15 and 13 nM, respectively.     

Development of a high performance liquid chromatographic method for systematic quantitative analysis of chemical constituents in rhubarb

HPLC methods for the systematic determination of 30 compounds in Rhei Rhizoma (rhubarb) were developed. Using a combination of mobile phase gradient conditions and UV detection at 280 nm, all 30 compounds were separated satisfactorily with low detection limits (0.05-2 microg/ml). The developed methods provided a reliable calibration curve for each compound. By adopting these methods, the determination of 30 compounds in three kinds of rhubarb samples, derived from Rheum tanguticum, R. palmatum and R. officinale, was achieved. The constituent pattern of each rhubarb was clearly characterized through the quantitative composition of 30 major constituents of rhubarb.     

微流控芯片光学检测技术在细胞研究中的应用与进展

重点综述了芯片上细胞培养和实时检测的微系统研究及相应检测方法和技术近年来的进展.总结了多种光学检测方法和技术体系的优缺点及发展趋势,讨论了各种方法技术对细胞研究模型的研究适用范围,探讨各种检测方法和技术对活细胞、单细胞实时无损无标记检测和传感发展前景和研究进展.最后对整个芯片实验室框架下细胞研究及传感微系统的发展方向进行了有益的思路和方法展望.     

形变Schrédinger-Virasoro 代数的非退化对称不变双线性型

本文确定了形变Schrödinger-Virasoro 代数的非退化对称不变双线性型, 并借助此类Lie 代数上的二上同调群, 确定了相应的Leibniz 二上同调群.     

Total Syntheses of Polyhydroxylated Steroids by an Unsaturation-Functionalization Strategy

Highly oxygenated cardiotonic steroids, such as ouabain, possess a wide spectrum of biological functions and remain significant synthetic challenges. Herein, we have applied an unsaturation-functionalization strategy and developed a synthetic method in addressing the C19-hydroxylation issue for efficient synthesis of polyhydroxylated steroids. An effective asymmetric dearomative cyclization allowed the construction of the C19-hydroxy unsaturated steroidal skeleton in only four steps from the Hajos-Parrish ketone ketal 7 . The synthetic sequence featured C3−OH-directed hydrogenation/epoxidation, m-CPBA-triggered epoxidation/S_N2′ nucleophilic substitution, Birch reduction of an enone, and regioselective LiAlH₄ reduction to furnish the polyhydroxy functionalities on the steroid skeleton with high stereochemical control and efficiency. This approach ultimately enabled the total synthesis of 19-hydroxysarmentogenin and ouabagenin in 18 and 19 steps, respectively, overall. The synthesis of these polyhydroxylated steroids offers synthetic versatility and practicality in the search for new therapeutic agents.     

Simple and convenient routes to new polyheterocycles incorporating pyrazole,thiazole, thiophene,and 1,3,4‐thiadiazole moieties

The cyanothioacetanilide derivative 3 reacted readily with either α‐halocarbonyl compounds 4 or α‐halodicarbonyl compounds 8 to afford the same thiophene derivatives 6 . Compound 3 also reacted with hydrazonoyl chlorides 12 and 16 and furnished the new polyheterocyles 14 and 17 , respectively. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:248–251, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/hc.10024