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R Clark  DC Ihde 《Canadian Metallurgical Quarterly》1998,12(5):647-58; discussion 661-3
Although small-cell lung cancer (SCLC) represents only 20% of all lung cancer cases in the United States, it is the most lethal subtype. Combination chemotherapy unequivocally offers the best chance for improved survival in SCLC. Either PE (platinum plus etoposide) or CAV (cyclophosphamide, Adriamycin, and vincristine) is a reasonable first-line therapy. Alternating PE with CAV does not appear to be significantly superior to PE or CAV alone. Increasing dose intensity, although sometimes associated with higher response rates, does not appear to significantly improve survival and should not be used outside of a clinical study. Several new agents with novel mechanisms of action show promise in treating SCLC. These include: gemcitabine (Gemzar), paclitaxel (Taxol), docetaxel (Taxotere), topotecan (Hycamtin), and irinotecan (Camptosar). Given the poor survival and response rates in relapsed patients and the chemoresponsiveness of SCLC, patients with newly diagnosed extensive disease should be encouraged to enroll in phase I or II trials. Thoracic radiotherapy confers a small survival advantage in limited-stage SCLC patients. Although prophylactic cranial irradiation does not significantly improve survival, it does reduce central nervous system (CNS) recurrences with minimal long-term sequelae. Surgery should be considered only for: (1) resection of a solitary pulmonary nodule, which must be followed by adjuvant chemotherapy; and (2) resection of an unresponsive chest tumor, which may harbor a non-small-cell lung cancer component.  相似文献   

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The National Cholesterol Education Program (NCEP) is a prime example of the role the National Heart, Lung, and Blood Institute has played, in its 50 years of existence, as a catalyst for translating research advances into improved clinical and public health practices. Since its inception in 1985, the NCEP has adhered to 2 principles in mounting educational campaigns for professionals and the public: building on a strong science base and working in partnership with other organizations. In slightly more than a decade, the NCEP has made significant progress toward its goal of reducing the prevalence of high blood cholesterol. The impact of cholesterol education is clearly visible in 4 major trends: increasing professional and public cholesterol awareness; declining dietary intakes of saturated fat, total fat, and cholesterol; falling serum cholesterol levels; and a continuing decline in coronary heart disease (CHD) mortality rates. Nevertheless, cholesterol levels are still being undertreated, especially in patients with CHD, and substantial scientific and educational challenges remain. As it looks forward to the 21st century, the NCEP plans to make continued progress by using emerging scientific developments and pursuing the powerful combination of cholesterol lowering in CHD patients and in primary prevention.  相似文献   

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During the second half of the 20th century, progress in developing novel, practical contraceptive methods for men has lagged significantly behind developments for women. Despite the lack of reliable, reversible methods, men throughout the world continue to be strongly involved in family planning but a greater involvement will require more attractive and reliable contraceptive options for men. The closest to fruition are hormonal methods the features of which are reviewed. Landmark WHO contraceptive efficacy studies have established that hormonally-induced azoospermia provides highly effective and reversible contraception for at least 12 months with minimal short-term side effects. Even among the small subgroup of men who remain oligozoospermic during hormonal suppression, good contraceptive efficacy is achieved. The present goals are to develop improved second generation hormonal regimens which provide more uniform azoospermia to obviate the need for monitoring of sperm output and to develop long-acting depot testosterone formulations used alone or with additional gonadotrophin suppressive agents such as progestins or GnRH antagonists. Significant obstacles to progress are the flight of industry from contraceptive R&D dur to the financial deterrent posed by the product liability crisis as well as the low priority accorded male reproductive health. Together those will determine whether the range of contraceptive options available to our children in the 21st century will improve, or whether the historically recent unbalanced increase in reliance on women for family planning will continue.  相似文献   

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A brief introduction to Baosteel's steelmaking plant,the increase of its crude steel output and development of its product variety in the past 25 years is given in this paper.The technical progress in hot metal pretreatment,converter,secondary refining,continuous casting,comprehensive utilization of resources and environmental protection is also introduced.The present situation and level of the technologies,such as production of clean steel,RH vacuum refining,breakout prediction system of slab continuous...  相似文献   

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 为明晰高炉中的氯元素对干法除尘高炉冶炼过程的影响,综述了高炉入炉料中氯元素的赋存状态、行为以及所带来的危害。进一步采用离子色谱法研究了国丰1号1 780 m3干法除尘高炉氯元素的来源, 焦炭和喷吹煤粉带入高炉中氯所占入炉料带入高炉中氯总量的比例分别为45.4 %和29.48 %, 而宝钢、唐钢和迁钢的3座干法除尘高炉中氯的来源主要是烧结矿,其比例分别为47.12 %、43.59%和44.89%,这主要与高炉入炉料种类、用量以及氯元素质量分数的不同有关,所以在对待高炉氯元素来源问题上应该具体高炉具体分析。通过热力学分析得出高炉入炉料中的氯化物在高炉内主要生成HCl,基于对高炉系统氯元素的研究,提出了高炉的降氯措施,并展望了高炉系统氯元素的未来研究方向。  相似文献   

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钛/钢层合板兼具钛的耐腐蚀性与钢的良好强度和塑性,广泛应用于海洋工程装备、水电站、核电站、核潜艇等领域.为进一步推动对钛/钢层合板的深入研究,促进钛/钢层合板的发展,对近年钛/钢层合板制备方法进行分析.分析发现轧制法作为一种经济、环保的制备方法,将会成为制备钛/钢层合板的主流工艺,因此重点讨论轧制钛/钢工艺参数、界面组...  相似文献   

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Discusses emerging issues in the discipline of health psychology. As the field matures, the impressive research gains of the last decade form a basis for a more synthetic and integrated research strategy. An important professional goal for the discipline is documenting treatment effectiveness. The cost-effectiveness of intervention strategies must be demonstrated. Another current issue is where research results should be published. When intervention is appropriate is a question the field as a whole must address. Theoretical concerns must continue to supplement applied science. The education of health psychologists is a current topic of debate. Health psychology has proven itself a growing field of science. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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中锰钢是近年来出现的新型钢铁材料,因为其优异的力学性能被认为是第三代汽车用钢,但是该钢的一个突出特点就是在拉伸变形时会发生塑性失稳,导致材料结构稳定性减弱甚至在某些情况下过早失效,这已然成为限制中锰钢商业化使用的关键问题。塑性失稳包括出现不连续屈服和屈服平台(吕德斯应变)以及流变应力锯齿(PLC效应)。两者都受到成分、晶粒形貌、退火工艺、组织构成等因素的影响,也均与拉伸变形过程中 奥氏体相变转变存在或强或弱的相关性,使得这一塑性失稳现象的机理更为复杂化,因而在近期各种观点迥异的理论解释也相继被提出。本文综述了相关研究中各种因素对吕德斯应变和PLC效应的影响结果及相关理论解释,并着重指出了各理论解释的局限性及未来的研究思路。最后,基于现有研究和预研实验对在保证中锰钢超高强度和优良塑性的前提下消除中锰钢塑性失稳现象的可行途径进行了展望。   相似文献   

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Human protein disulfide isomerase with an extra 10 amino acid residues of AEITRIDPAM at the N-terminal was expressed in E. coli as a soluble protein comprising 20% of total cell proteins, and was purified to near homogeneity through one step of DEAE-Sephacel chromatography. The mutant enzyme, which had the same CD spectrum and comparable disulfide isomerase and thiol-protein oxidoreductase activities with that of the wild type human and bovine protein disulfide isomerases, also showed chaperone-like activity in stimulating the refolding of proteins containing no disulfide bond. The overall yield of the active product is about 20 mg 1-1 culture.  相似文献   

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In Table 4, current "state-of-the-art" screening for various cancers is summarized. It is fair to say that, unfortunately, only a minority of the tumors do have proven screening methods that lead to a lower disease-specific mortality. Given the relative lack of improvement in survival rates over the last few decades, this area should be a priority for research endeavors.  相似文献   

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In the past 40 years, transplantation has moved from an experimental form of therapy used almost exclusively for renal failure to an accepted treatment for end-stage kidney disease, heart disease, liver disease, lung disease, and diabetes mellitus. Tissue transplantation for conditions from thermal injury to Parkinson disease is being investigated. The primary barrier in transplantation medicine is the immunologic reaction of the recipient to donor organs and tissues. Currently available drugs permit excellent short-term graft survival but have not led to reliable long-term survival. Recent advances in the understanding of this immune response have suggested new approaches to induction of immunologic tolerance and reduction of late graft losses. Because of the excellent short-term success of current agents, integration of these new approaches into clinical trials is challenging and raises important questions about the design of such trials.  相似文献   

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