Brown University Division of Biology and Medicine
Center for Statistical Sciences
Fall 2005 Seminar Series
Division of Cancer Prevention National Cancer Institute, National Institute of Health | |
Abstract: Identification of relevant cancer risk factors based on experimental and epidemiologic research findings has led to cancer prevention clinical trials aimed at reducing the burden of cancer on society. This seminar will focus on clinical trials for prevention of cancer in former smokers, and in the breast and prostate using drugs and bioactive food compounds. As a public health strategy, cancer prevention includes lifestyle approaches, such as encouraging healthy eating, physical activity, and smoking cessation, as well as medical interventions. Lung, breast, and prostate cancers account for almost one-half of new cases of cancer each year. Medical approaches for lung cancer prevention in former smokers include development of chemopreventive agents and of antinicotine vaccines, which suppress the desire to smoke. The major thrust of randomized controlled prevention trials for breast and prostate cancers has been on the modulation of hormones and nutritional modifications using natural or synthetic bioactive food components. The Breast Cancer Prevention Trial using the estrogen antagonist tamoxifen cut the occurrence rate of breast cancer in half, with the benefit limited to prevention of estrogen receptor positive tumors. Current trials aim to see if that can be improved upon both in efficacy and in reducing adverse events. Raloxifene -- another estrogen receptor modifier -- is in a head-to-head trial against tamoxifen, with future plans to test the winner against an aromatase inhibitor. Earlier phase trials use other compounds to see if they can reduce the risk of estrogen receptor negative breast cancers.
Agents that modify testosterone activity have shown effectiveness in treatment and prevention of prostate cancer. Finasteride, which prevents conversion of testosterone to its more potent form, was tested in the Prostate Cancer Prevention Trial and caused a 25 percent reduction in prostate cancers incidence. Studies are underway to learn how better to differentiate aggressive from indolent prostate cancers. Bioactive food compounds such as selenium, vitamin E, soy isoflavones, and green tea polyphenols also have shown promise in reducing prostate cancer incidence. The Selenium and Vitamin E Cancer Prevention Trial (SELECT) is investigating whether a 7- to 12-year regimen of daily selenium and/or vitamin E supplements and/or placebo in a factorial intervention design will decrease the risk of prostate cancer (as the primary endpoint) in approximately 32,000 healthy men. Future prospects for cancer prevention include public guidance about what is known as the research continues, a broader system of clinical trials in cancer prevention , development of cancer prevention vaccines, and building cancer prevention into the mainstream of major research institutions and into clinical practice.
Brown University
Joint Materials/Solid Mechanics Seminar Series
Sandia National Laboratories, Albuquerque, NM 87185 | |
Abstract: The fundamental mechanisms of thin film stress have been under investigation since 1877 when J. Mills coated the bulb of a thermometer with Cr to act as the cathode for electrodeposition. During deposition, Mills recorded the change in height of the mercury, which provided the first real-time in-situ measurement of stress generation during thin film growth. Since that time there have been numerous breakthroughs in the understanding of what induces intrinsic stress during thin film growth, e.g. epitaxy, island coalescence, and capillarity stress. However, there is still a ubiquitous compressive stress generation mechanism that is observed in most metal films, independent of deposition technique, whose origins have yet to be definitively determined. In this presentation, we examine the stress evolution of Ni and NiMn during electrodeposition to highlight the importance of the different intrinsic stress mechanisms during the various stages of thin film growth. We will compare the different compressive stress generation mechanisms that have been proposed in the literature. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.
Stochastic Systems Seminar
Abstract: The Markov chain approximation method is widely used for the numerical solution of Stochastic centrol problems in continuous time. There have been extensions to zero-sum stochastic dynamical games, with proofs of convergence.
For the non-zero sum game problem, there have been successful numerical applications, but proofs have been lacking. The problem will be outlined and a proof given.
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