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291.
Breast cancer still remains a major problem in its incidence, morbidity and mortality; therefore, more effective strategies for its prevention are urgently needed. Retinoids, natural and synthetic derivatives of vitamin A, possess antiproliferative and proapoptotic properties, making them a promising class of chemopreventive agents against breast cancer. The efficacy of all-trans retinoic acid, 9-cis-retinoic acid, LGD1069 (Targretin, bexarotene), and N-(4-hydroxyphenyl)retinamide (fenretinide) as breast cancer chemopreventive agents is being studied. A better understanding of the molecular mechanisms of action of these agents should lead to improvements in their clinical application. In this review, we discuss the mechanisms by which retinoids exert their antiproliferative and apoptotic effects in breast cancer cells.Received 5 January 2004; received after revision 9 February 2004; accepted 12 February 2004 相似文献
292.
回顾了《清洁生产促进法》立法之前清洁生产在我国的发展史,以及在此期间政府、企业、广大技术人员所做出的努力.十年前在联合国环境规划署的推动下,我国清洁生产首先在制浆造纸等行业启动并推行,北京工商大学项目组也做了很多具体工作,并为我国在国际上争得了荣誉.今天清洁生产已深入到各行各业的基层,并遍及全国,生态工业园区、循环经济等模式的成功示范,使清洁生产理论在实践中获得不断发展. 相似文献
293.
辅导员对学生的教育培养,“言教”固不可少,“身教”更为重要,二者相辅相成,缺一不可。从某种意义上讲,“身教”是“言教”取得效果的前提和保障。 相似文献
294.
Melanocortin receptors: their functions and regulation by physiological agonists and antagonists 总被引:14,自引:0,他引:14
Abdel-Malek ZA 《Cellular and molecular life sciences : CMLS》2001,58(3):434-441
The melanocortins are a family of bioactive peptides derived from proopiomelanocortin, and share significant structural similarity.
Those peptides are best known for their stimulatory effects on pigmentation and steroidogenesis. Melanocortins are synthesized
in various sites in the central nervous system and in peripheral tissues, and participate in regulating multiple physiological
functions. Research during the past decade has provided evidence that melanocortins elicit their diverse biological effects
by binding to a distinct family of G protein-coupled receptors with seven transmembrane domains. To date, five melanocortin
receptor genes have been cloned and characterized. Those receptors differ in their tissue distribution and in their ability
to recognize the various melanocortins and the physiological antagonists, agouti signaling protein and agouti-related protein.
These advances have opened new horizons for exploring the significance of melanocortins, their antagonists, and their receptors
in a variety of important physiological functions.
Received 5 October 2000; accepted 10 November 2000 相似文献
295.
对于一般情形下的Chwa & Hakimi模型,在不以“t-可诊断性”和“相信大多数”作前提假设的情况下,找到了求全体相容故障模式的具体方法——方程诊断算法,实践证明,诊断效果理想。 相似文献
296.
This paper seeks to explore a philosophical ground for the formulation and practice of an Oriental systems methodology, the wuli–shili–renli approach (WSR). Drawing insights from ancient Chinese thought, WSR contends that, in sociotechnical systems design/management, we should investigate and follow wuli, shili, and renli, which constitute a differentiable, dynamic whole. Wuli, shili, and renli condition and determine the fate of our projects, meaning different methods are needed to deal with each differentiable aspect. It also points out that, to deal with wuli, shili, and renli properly, we need to engage in encounters with the "dark side" of Confucianism and with the contemporary tendency of scientism. 相似文献
297.
Power-Based Arbitrary Decisional Actions in the Resolution of MIS Project Issues: A Project Manager's Action Research Perspective 总被引:1,自引:0,他引:1
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. 相似文献
298.
结合高等职业数学教学的现状,指出了当前学生应用数学意识薄弱的主要原因,并针对性地提出了培养数学应用能力的主要途径。 相似文献
299.
300.
A time delay equation for sea-air oscillator model is studied. The aim is to create an asymtotic solving method of nonlinear equation for the ENSO model. And based on a class of oscillators of ENSO model, employing the variational iteration method, the approximate solution of corresponding problem is obtained. It is proven from the results that the method of variational iteration method can be used for analyzing the sea surface temperature anomaly in the equatorial eastern Pacific of the atmosphere-ocean oscillation for ENSO model. 相似文献