￣（45）Ca跨膜流动测定技术用于中药钙拮抗作用的研究

应用￣（４５）Ｃａ跨膜流动测定技术研究钙拮抗剂ｖｅｒａｐａｍｉｌ、中药西红花（ＣｒｏｃｕｓＳａｔｉｖｕｓＬ．）、“地奥心血康”（ＤＡＸＸＫ）、川红花（ＣａｒｔｈａｍｕｓｔｉｎｃｔｏｒｉｕｓＬ．）及银杏叶（ＧｉｎｋｇｏｂｉｌｏｂａＬ．）等对大鼠主动脉￣（４５）Ｃａ跨膜内流的作用，以确定其对细胞膜Ｃａ￣（２＋）通道影响。实验结果表明：西红花、川红花、ＤＡＸＸＫ对平滑肌细胞膜上电压依赖Ｃａ￣（２＋）通道（ＰＤＣ）和受体操纵Ｃａ￣（２＋）通道（ＲＯＣ）都有阻滞作用，并以西红花的阻滞作用最强；而银杏叶对细胞膜Ｃａ￣（２＋）通道无阻滞作用。     

双核铕－邻甲基苯甲酸－邻菲罗啉三元配合物的晶体结构

双核铕－邻甲基苯甲酸－邻菲罗啉三元配合物的晶体结构王瑞芬，王明昭，金林培，蔡冠梁（北京师范大学化学系，１００８７５，北京；解放军防化指挥工程学院，１０２２０５，北京；第一作者，４４岁，女，副教授）关键词铕；三元配合物；晶体结构分类号Ｏ７４１．６；Ｏ６...     

Extraction of a weak climatic signal by an ecosystem

The complexity of ecosystems can cause subtle and chaotic responses to changes in external forcing. Although ecosystems may not normally behave chaotically, sensitivity to external influences associated with nonlinearity can lead to amplification of climatic signals. Strong correlations between an El Ni?o index and rainfall and maize yield in Zimbabwe have been demonstrated; the correlation with maize yield was stronger than that with rainfall. A second example is the 100,000-year ice-age cycle, which may arise from a weak cycle in radiation through its influence on the concentration of atmospheric CO2 (ref. 5). Such integration of a weak climatic signal has yet to be demonstrated in a realistic theoretical system. Here we use a particular climatic phenomenon-the observed association between plankton populations around the UK and the position of the Gulf Stream-as a probe to demonstrate how a detailed marine ecosystem model extracts a weak signal that is spread across different meteorological variables. Biological systems may therefore respond to climatic signals other than those that dominate the driving variables.     

Power-Based Arbitrary Decisional Actions in the Resolution of MIS Project Issues: A Project Manager's Action Research Perspective

As a management information systems (MIS) project manager and an action researcher, the author examined, over time, the influence on information system development (ISD) of the informal sociopolitical organizational actions. The paper reports two cases of action research findings concerning the effect on ISD project implementation processes of power-based arbitrary decisional actions in bureaucratic environments. The research focused on the relationship of such unilateral actions to the interconnected subprocesses of deliberate and conscious attempts by the ISD project members to define and resolve system implementation issues. A suggested conceptual framework for the issue-resolution processes (IRP's) and obstacle-coping processes (OCP's) is based on the author's IRP/OCP-related behavioral constructs and theoretical models dealing with soft-systems issues, especially appreciative system theory and soft-systems methodology, and innovative flexible, "complementarist" (Sinn, 1998) or pluralist problem-solving approaches.     

我国证券市场混沌的判据

本文通过李雅普诺夫指数和吸引子的分数维这两个指数来研究我国证券市场的混沌特征。利用Ｗｏｌｆ提出的重构相空间技术和Ｇ－Ｐ算法分别计算了上证综指日收益率序列的李雅普诺夫指数和吸引子的分数维。从而得出我国证券市场运行于混沌状态的有力证据。     

基于支持向量机的体数据分类算法研究

在由工业CT图像构成的体数据中,低密度材质的灰度与背景及伪影的灰度接近,影响了分类的准确性,进而影响体绘制的结果.针对这一问题,提出了一种基于支持向量机的体数据分类算法.首先以体素的灰度、梯度、局部直方图的熵和矩为样本特征进行训练,得到决策函数,并通过决策函数对体数据进行类别标记,再将具有相同标记的体素的灰度值变换到指定的灰度区间,最后利用阻光度传递函数对体素进行阻光度赋值,完成体数据的分类.实验结果表明,所提出的算法较好的实现了体数据的分类,体绘制结果清晰,且能够实现试件的模拟拆卸.     

利用元胞自动机模拟滩角地形

滩角是滩面上的一种特征地形.本文利用改进的元胞自动机模型,对滩角地形进行了模拟.结果表明滩角的形成过程具有自组织特征,因此滩角可以通过海滩泥沙、地形与波、流的自组织过程形成.指出自组织理论为从不同的侧面认识和研究海岸带现象与过程提供了一扇窗口.     

Human peripheral blood monuclear cells transfected with messenger RNA stimulate antigen-specific cytotoxic T-lymphocytes in vitro

The efficiency of test vaccines needs to be evaluated by quantification of the triggered cellular immune response. Usually, for these assays, autologous target cells expressing the vaccine antigen are required. In the context of messenger RNA (mRNA)-based vaccinations, the target cells used for the read-out are mRNA-transfected monocyte-derived dendritic cells (Mo-DCs). Their production typically requires samples of 100 ml blood from the patients, and limits the number of assays that can be performed. We show here that fresh peripheral blood mononuclear cells (PBMCs) can be transfected with mRNA by electroporation. Such cells are as efficient as mRNA-transfected Mo-DCs for their ability to activate memory T cells in vitro. Thus, mRNA-transfected PBMCs are a convenient replacement of mRNA-transfected Mo-DCs for the in vitro monitoring of natural or vaccine-induced immune responses.Received 17 February 2005; received after revision 1 May 2005; accepted 7 Juni 2005     

Phosphodiesterase: overview of protein structures, potential therapeutic applications and recent progress in drug development

Phosphodiesterases (PDEs) are essential regulators of cyclic nucleotide signaling with diverse physiological functions. Because of their great market potential and therapeutic importance, PDE inhibitors became recognized as important therapeutic agents in the treatment of various diseases. Currently, there are seven PDE inhibitors on the market, and the pharmacological and safety evaluations of many drug candidates are in progress. Three-dimensional (3D) structures of catalytic domains of PDE 1, -3, -4, -5 and -9 in the presence of their inhibitors are now available, and can be utilized for rational drug design. Recent advances in molecular pharmacology of PDE isoenzymes resulted in identification of new potential applications of PDE inhibitors in various therapeutic areas, including dementia, depression and schizophrenia. This review will describe the latest advances in PDE research on 3D structural studies, the potential of therapeutic applications and the development of drug candidates.Received 30 November 2004; received after revision 24 January 2005; accepted 5 February 2005