白茅根化学成分、药理作用及在保健品开发中的应用

白茅根用于防病保健已达2千年的历史,近年来在保健品开发中有广泛的应用。对其化学成分及药理研究也取得了一定进展,但2010版《中国药典》对白茅根尚无明确的质量控制方法。其主要化学成分和生物活性的关系,尚须进行系统研究,以期建立白茅根完整的质量控制体系。     

化学实验室危险、剧毒、易制毒化学品的管理异同

通过对高等学校化学实验室危险化学品、剧毒化学品、易制毒化学品的采购、运输、库房保管、领取、使用等方面的管理异同进行比较,保证剧毒化学品和易制毒化学品的合法使用,消除安全隐患,提高高等学校化学实验室危险化学品、剧毒化学品、易制毒化学品的安全管理水平.     

水污染及污水处理

防治水污染是当今世界性的问题，本文对形成水污染的重要因素进行了论述，提出了污水处理的技术方法。     

Mathcad用于热分解动力学模型参数的优化

利用数学工具软件Mathcad2001,对4Na2SO4·2H2O2·NaCl加合物的热分解动力学方程模型中的参数进行优化,得到了其热分解动力学方程式,优化的结果能准确地模拟4Na2SO4·2H2O2·NaCl的实际分解过程.Mathcad的使用大大减少了计算工作量.对于其它物质的热分解过程、非均相及均相体系反应的动力学方程式参数都可用Mathcad2001工具软件进行优化.     

在化工原理实验课教学中培养学生能力的实践研究

研究了在化工原理实验课程的教学中如何培养学生能力的问题,根据教育教学理论和人的认识规律,讨论了在该课程的教学中培养学生能力的有效途径和方法。指出,设置研究型实验课题、预留问题提供思考空间、提出挑战性问题是化工原理实验课程教学中培养学生能力的有效途径。     

Editorial

Every teacher in England is a member of the General Teaching Council (GTC). Membership is compulsory. The GTC is an independent professional body with a governing council of 64 members. Forty-four council members are practising teachers, including 25 elected teachers. There are representatives from the teacher unions and associations, equality bodies, local government, governors and parents. The GTC regularly produce 25 leaflets about professional issues and the spring issue of 2003 began with the title ‘Keeping teachers in teaching’. A number of key aspects were highlighted: ‘Placing learning at the centre’, ‘Teachers as leaders of learning’, ‘Retention—what teachers want’, ‘Research of the month’, ‘GTC seeks new ways to recognise teachers' professionalism’ and ‘GTC response to workload reform’. An interesting section entitled ‘Some key findings’ revealed data that should disturb even the most optimistic politician. Fifty per cent of teachers nationally are aged over 45 years, 22% of teachers are aged 35–44 years, and 73% of teachers are women. The significance of the last point was not discussed. Also, retention data were not included.     

A comparison of methods to determine maximal accumulated oxygen deficit in running

Abstract

The aim of this study was to compare maximal accumulated oxygen deficit (hereafter O₂ deficit) estimated from the methods of Whipp et al. (1986 Whipp, B. J., Ward, S. A. and Wasserman, K. 1986. Respiratory markers of the anaerobic threshold. Advances in Cardiology, 35: 47–64. [Crossref], [PubMed] , [Google Scholar]), Medbo et al. (1988 Medbo, J. I., Mohn, A. C., Tabata, I., Bahr, R., Vaage, O. and Sejersted, O. M. 1988. Anaerobic capacity determined by maximal accumulated O₂ deficit. Journal of Applied Physiology, 64: 50–60. [PubMed], [Web of Science ®] , [Google Scholar]), and Hill et al. (1998 Hill, D. W., Ferguson, C. S. and Ehler, K. L. 1998. An alternative method to determine maximal accumulated O₂ deficit in runners. European Journal of Applied Physiology, 79: 114–117. [Crossref], [Web of Science ®] , [Google Scholar]) to determine whether they agree sufficiently to be used interchangeably. Nineteen moderately to highly trained endurance runners first performed an incremental test to exhaustion for the determination of maximal oxygen uptake ([Vdot]O_2max) and peak treadmill speed, followed by six randomly ordered constant-speed tests at 95, 100, 105, 110, 110, and 120% of peak treadmill speed. All tests were separated by at least 72 h and were performed within 4 weeks. The method of Whipp produced an O₂ deficit estimate that was lower than that derived from the method of Hill or Medbo (bias ± 95% limits of agreement: ?29.6 ± 36.6 and ?26.1 ± 32.8 ml · kg^?1, respectively; P < 0.001). The O₂ deficit did not differ between the methods of Hill and Medbo (bias ± 95% limits of agreement: 3.5 ± 41.6 ml · kg^?1; n.s.). However, poor correlations (0.21 < r < 0.33; n.s.) together with wide limits of agreement between O₂ deficit estimates (70 – 80% of the mean response) clearly question using these methods interchangeably.     

A comparison of the reverse and power punches in oriental martial arts

Abstract

In this study, we compared mechanical factors in the reverse and three-inch power punches. Twelve expert male martial artists stood on a force plate, and executed reverse and power punches against a padded target fixed to a wall-mounted force plate. The force plates measured horizontal forces, and subsequently impulses and body centre of mass velocity changes. The motions of four markers attached to the arm were also collected, and were used to compute the horizontal velocities of the knuckle and of the arm centre of mass. The power punch produced smaller velocities immediately before impact than the reverse punch for the whole-body centre of mass (0.14 vs. 0.31 m · s^?1), for the arm centre of mass (2.86 vs. 4.68 m · s^?1), and for the knuckle (4.09 vs. 6.43 m · s^?1). The peak force exerted by the fist was much smaller in the power punch than in the reverse punch (790 vs. 1450 N). However, the linear impulse exerted by the fist during the first 0.20 s of contact was slightly larger in the power punch than in the reverse punch (43.2 vs. 37.7 N · s). The results indicate that the power punch is less potent than the reverse punch, but slightly more effective for throwing the opponent off balance.     

Intensity-level assessment of lower body plyometric exercises based on mechanical output of lower limb joints

Abstract

The present study aimed to quantify the intensity of lower extremity plyometric exercises by determining joint mechanical output. Ten men (age, 27.3 ± 4.1 years; height, 173.6 ± 5.4 cm; weight, 69.4 ± 6.0 kg; 1-repetition maximum [1RM] load in back squat 118.5 ± 12.0 kg) performed the following seven plyometric exercises: two-foot ankle hop, repeated squat jump, double-leg hop, depth jumps from 30 and 60 cm, and single-leg and double-leg tuck jumps. Mechanical output variables (torque, angular impulse, power, and work) at the lower limb joints were determined using inverse-dynamics analysis. For all measured variables, ANOVA revealed significant main effects of exercise type for all joints (P < 0.05) along with significant interactions between joint and exercise (P < 0.01), indicating that the influence of exercise type on mechanical output varied among joints. Paired comparisons revealed that there were marked differences in mechanical output at the ankle and hip joints; most of the variables at the ankle joint were greatest for two-foot ankle hop and tuck jumps, while most hip joint variables were greatest for repeated squat jump or double-leg hop. The present results indicate the necessity for determining mechanical output for each joint when evaluating the intensity of plyometric exercises.     

Children-Adult Comparisons of VO2 and HR Kinetics during Submaximum Exercise

Abstract

Oxygen uptake (VO₂) and heart rate (HR) kinetics for submaximum exercise were compared in prepubescent boys (mean age ± SD = 10.2 ± 1.28 years, N = 21) and adult men (30.0 ± 5.64 years, N = 21). Standard open circuit spirometric techniques were used to determine _VO2 and a bipolar ECG was used to measure HR. The kinetics of VO₂ and HR were determined for each subject using graphic procedures. Subjects performed submaximum exercise on the bicycle ergometer at an intensity of 42 ± 1.3% (mean ± SE) of VO₂ max for the children and 39 ± 0.7% of VO₂ max for the adults (p = .07). There were no group differences in VO₂ t1/2 (children t1/2 = 18.5 ± 0.75 secs and adults t1/2 = 17.4 ± 0.39 secs, p = .18) and HR t1/2 (children t1/2 = 11.4 ± 1.86 secs and adults t1/2 = 13.6 ± 1.66 secs, p = .38). These data suggest that children and adults do not differ in cardiorespiratory adjustments during low intensity exercise. This is in contrast to suggestions of other investigators that children have a faster cardiovascular adjustment to exercise.