含巯基胞嘧啶的多核苷酸及单核苷酸对人癌细胞株的抑制作用(摘要)     

耿宝琴  何佑钧  Bardos  T.J. 《科技通报》1986,(6)

5巯基胞嘧啶多核苷酸(5-Mercaptopolycytidylic acid,MPC)是DNA和RNA聚合酶的强有力抑制剂,亦能抑制白血病小鼠的骨髓和脾细胞的集落形成。德国临床试用表明MPC对小儿急性淋巴细胞性白血病有一定效果。本文报道MPC体外对人癌细胞株(肺癌A549,大肠癌HT-29,成骨肉瘤HOS)及正常羊膜细胞株(WISH)的抑制作用,并与Poly Ⅰ·MPC(系由等分子量的MPC和多次黄嘌呤核苷酸合成)作比较。为了了解这种抑癌作用究系MPC本身抑或由其降解产物所致,还同时观察了MPC、5巯基胞嘧啶核苷酸(SH~5-CMP)及5巯基胞嘧啶对上述细胞株的影响。  相似文献   

光电化学太阳电池     

阎世才  John T.MeDevitt 《天水师范学院学报》1986,(2)

我们每天都要从太阳获取大量的能量。有人计算过,太阳在两周时间内给予地球的能量,大约相当于地球最初可以提供给人们的化石燃料所含能量的总和。从二十世纪五十年代起,人们就一直非常重视利用光电化学效应将太阳能直接转变成电能或合成燃料的研究,随着能源危机的不断提出,这个领域内的研究也一天比一天变得更加普遍和重要。本文将介绍一种实用的太阳电池的简易制备方法,同时。回顾关于太阳能转变方面的一些知识。  相似文献   

The Mayo Memorial Medical Center at the University of Minnesota     

ROMSON T  STANFORD EB 《Bulletin of the Medical Library Association》1958,46(2):274-280

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The relationship between qualified personnel and self-reported implementation of recommended physical education practices and programs in U.S. schools     

Davis KS  Burgeson CR  Brener ND  McManus T  Wechsler H 《Research quarterly for exercise and sport》2005,76(2):202-211

The authors analyzed data from the School Health Policies and Programs Study 2000 to assess the associations between the presence of a district physical education coordinator and district-level physical education policies and practices recommended by federal government agencies and national organizations. The authors also examined the relationship between teacher qualifications and staff development related to physical education and self-reported implementation of recommended teachingpractices. District-level data were collected by self-administered mail questionnaires from a nationally representative sample of school districts. Classroom-level data were collected by computer-assisted personal interviews with teachers of randomly selected classes in elementary schools and randomly selected required physical education courses in middle/junior high and senior high schools. Nearly two thirds (62.2%) of districts had a physical education coordinator, and those were generally more likely than other districts to report having policies and practices that corresponded with national recommendations for high-quality physical education programs. More than two thirds of teachers (66.9%) met the criteria for teacher qualifications based on their education and certification. These teachers were more likely than others to report use of certain recommended physical education teaching practices. Teachers who participated in staff development also were more likely to use recommended teaching practices in their classrooms. Using a district physical education coordinator and teachers with appropriate qualifications as well as offering staff development opportunities on physical education may enhance school physical education programs.  相似文献   

A single session of resistance exercise does not reduce postprandial lipaemia     

Burns SF  Corrie H  Holder E  Nightingale T  Stensel DJ 《Journal of sports sciences》2005,23(3):251-260

This study investigated the effect of a single session of resistance exercise on postprandial lipaemia. Eleven healthy normolipidaemic men with a mean age of 23 (standard error = 1.4) years performed two trials at least 1 week apart in a counterbalanced randomized design. In each trial, participants consumed a test meal (1.2 g fat, 1.1 g carbohydrate, 0.2 g protein and 68 kJ x kg(-1) body mass) between 08.00 and 09.00 h following a 12 h fast. The afternoon before one trial, the participants performed an 88 min bout of resistance exercise. Before the other trial, the participants were inactive (control trial). Resistance exercise was performed using free weights and included four sets of 10 repetitions of each of 11 exercises. Sets were performed at 80% of 10-repetition maximum with a 2 min work and rest interval. Venous blood samples were obtained in the fasted state and at intervals for 6 h postprandially. Fasting plasma triacylglycerol (TAG) concentration did not differ significantly between control (1.03 +/- 0.13 mmol x l(-1)) and exercise (0.94 +/- 0.09 mmol x l(-1)) trials (mean +/- standard error). Similarly, the 6 h total area under the plasma TAG concentration versus time curve did not differ significantly between the control (9.84 +/- 1.40 mmol l(-1) x 6 h(-1)) and exercise (9.38 +/- 1.12 mmol x l(-1) x 6 h(-1)) trials. These findings suggest that a single session of resistance exercise does not reduce postprandial lipaemia.  相似文献   

Prediction equation for head volume of Japanese young adults     

Demura S  Yamaji S  Nakada M  Kitabashi T  Minami M 《Journal of sports sciences》2005,23(5):541-548

Accurate measurement of head volume is indispensable for precise assessments of body composition determined by hydrostatic weighing without head submersion. The purpose of this study was to establish a prediction equation for head volume measured by the immersion method from multiple regression analysis using head parameters (head circumference, head length, head breadth, neck girth and head thickness) as independent variables. The participants were 106 Japanese young adults (55 males and 51 females) aged 17-27 years. Intra-class correlation coefficients (ICCs) for each head parameter and head volume in males and females were very high (ICC = 0.993-0.999, 0.992-0.998). Head circumference was closely related to head volume measured by the immersion method (r = 0.719, 0.861, P < 0.05), and was the most important parameter for the prediction equation in both sexes. Head breadth was related poorly (r = 0.475, 0.500, P < 0.05) and showed a small individual difference. It was, therefore, excluded from the independent variables. The prediction equation for males was predicted head volume = 122.10X1 + 106.19X3 + 37.16X4 - 89.46X5 - 4754.93, R = 0.909, SEE = 121.75 ml, and that for females was predicted head volume = 213.83X1 + 45.24X3 + 36.85X4 - 74.34X5 - 8912.43, R = 0.913, SEE = 136.26 ml (where X1 = head circumference, X3 = head length, X4 = neck girth, X5 = head thickness, and SEE = standard error of the estimate). The limits of agreement for predicted and measured head volume were -234.5 to 234.1 ml for males, and -261.0 to 261.0 ml for females. In cross-validation groups of both sexes, there were no significant differences between measured head volume and predicted head volume. The correlation coefficients between measured head volume and predicted head volume in males and females were 0.894 and 0.908, respectively. The predicted head volume from prediction equations was considered to have high reliability and validity.  相似文献   

An ergonomics model of the soccer training process     

Reilly T 《Journal of sports sciences》2005,23(6):561-572

An ergonomics model of training is described in which the demands of the game and the fitness profiles of soccer players are placed in perspective. The demands of the game may be gauged by monitoring the work rate of players during matches and the concomitant physiological responses. These indices suggest an increased tempo in contemporary professional soccer compared with previous decades, a trend replicated in the fitness levels of players. The simulation of the exercise intensity corresponding to match-play has enabled sport scientists to study discrete aspects of play under laboratory conditions. Observations highlight the value of exercising with the ball where possible, notably using activity drills in small groups. Small-sided games have particular advantages for young players, both in providing a physiological training stimulus and a suitable medium for skills work. While complementary training may be necessary in specific cases, integrating fitness training into a holistic process is generally advisable.  相似文献   

有氧代谢向无氧代谢的过渡     

J·斯金纳  T·麦克莱伦 《体育与科学》1982,(1)

本文综述了有氧和无氧代谢复杂生化机制的新材料。不考虑这些材料,很难使对肌肉代谢过程的认识向深入和正确的方向发展。这同正确掌握训练直接有关。  相似文献   

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T.��.����ݴĿ�� 《图书情报工作》1962,7(7):12-21

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无与伦比的简·奥斯汀     

T.A.Jackson  倪培龄 《湖南师范大学社会科学学报》1979,(4)

长篇小说中的古典派典型,原是亨利·菲尔丁所创始的,但对于没有尝试过这种写作手法的人来说,要想坚持这个传统,谈何容易。避免一切过分与夸张,这准则也只是具有最完美写作技巧的艺术大师,并且通过毕生努力,才能获得的一种才能。  相似文献