心理训练在篮球教学中的作用

现代篮球教学训练是对运动员体力、技术、心理和智力等因素的共同开发,心理因素对创造运动成绩起着重要作用.本文旨在用试验结果和教学经验制定的综合心理训练方法,丰富常规教学手段,并在篮球教学中提高心理训练的作用提出建议.     

非线性Schrdinger方程的基暗孤子解

采用两种方法分别求出了非线性Schrdinger(NLS)方程的一般形式的基暗孤子解。一是对NLS方程进行直接求解;另一是基于NLS方程解的性质,由静止基暗孤子解导出了一般形式的基暗孤子解。     

金沙江水系鱼体中稀土元素环境背景值研究

采用等离子发射光谱法测定了金沙江水系鱼体肌肉中十个稀土元素的含量。根据统计方法提供了金沙江水系鱼体中稀土元素环境背景值。它们分别是:La 0.064mg·kg~(-1),Ce 0.156mg·kg~(-1),Pr 0.080mg·kg~(-1),Nd 0.025mg·kg~(-1),Eu 0.002mg·kg~(-1),Dy 0.009mg·kg~(-1),Er 0.019mg·kg~(-1),Yb 0.007mg·kg~(-1)和Y 0.015mg·kg~(-1)。结果表明:金沙江水系鱼体肌肉中稀土元素含量与江水中溶解态稀土元素含量有关。同时获得了该水系十个稀土元素的生物富因子。     

Functional investigations of exercising muscle: a noninvasive magnetic resonance spectroscopy-magnetic resonance imaging approach

Muscle fatigue, which is defined as the decline in muscle performance during exercise, may occur at different sites along the pathway from the central nervous system through to the intramuscular contractile machinery. Historically, both impairment of neuromuscular transmission and peripheral alterations within the muscle have been proposed as causative factors of fatigue development. However, according to more recent studies, muscle energetics play a key role in this process. Intramyoplasmic accumulation of inorganic phosphate (P_i) and limitation in ATP availability have been frequently evoked as the main mechanisms leading to fatigue. Although attractive, these hypotheses have been elaborated on the basis of experimental results obtained in vitro, and their physiological relevance has never been clearly demonstrated in vivo. In that context, noninvasive methods such as 31-phosphorus magnetic resonance spectroscopy and surface electromyography have been employed to understand both metabolic and electrical aspects of muscle fatigue under physiological conditions. Mapping of muscles activated during exercise is another interesting issue which can be addressed using magnetic resonance imaging (MRI). Exercise-induced T2 changes have been used in order to locate activated muscles and also as a quantitative index of exercise intensity. The main results related to both issues, i.e. the metabolic and electrical aspects of fatigue and the MRI functional investigation of exercising muscle, are discussed in the present review.Received 4 September 2003; received after revision 4 December 2003; accepted 22 December 2003     

肌肉力量衰退与中老年人的力量训练

从生理生化角度分析了肌肉力量的生长发育规律,以及肌肉中肌纤维和结缔组织的自然衰退规律,阐述了中老年肌肉力量锻炼的必要性与可行性,提出了中老年人进行肌肉力量训练应强化Ⅱ型肌纤维、易衰退肌肉和柔韧性的训练等建议。     

陶瓷ZrO2晶粒的透射电镜研究

运用透射电子显微镜中的暗场技术,观察和研究了陶瓷ZrO2多晶试样的晶粒形貌特征。在暗场像下能清楚观察到其晶粒呈六方片状,尺寸在305nm到410nm之间。与明场像相比,暗场像中晶粒的取向衬度更加明显,暗场技术是研究和观察多晶颗粒形态和尺寸的有力工具之一。     

α-硫辛酸对小牛血管细胞氧化损伤的保护作用

为了研究α-硫辛酸（lipoic acid, LA）对心血管氧化损伤的保护作用，本研究以离体培养的小牛主动脉血管内皮细胞和平滑肌细胞为实验材料，探讨了LA 对这两种细胞氧化损伤的影响.结果表明，在H2O2胁迫下，LA可以剂量依赖性地提高细胞内的超氧化物歧化酶（SOD）活性，抑制细胞内过氧化产物丙二醛（MDA）的产生，提示LA对小牛主动脉血管内皮细胞和平滑肌细胞氧化损伤有保护作用.本研究为LA的保健和药用价值开发,特别是对LA在保护心血管免受氧化损伤的功效的研发，提供了自由基生物学实验依据.     

Frequency-dependent effect of verapamil on rat soleus muscle

Summary In the presence of verapamil (0.1 mM) rat soleus muscle fibers failed to generate action potentials with overshoots. In fibers with their V_m set to a local level of –90 mV, verapamil produces a gradual reduction in the amplitude of the repetitive action potentials; this effect is more pronounced at high rates of stimulation (100 Hz). Our results suggest a local anesthetic action of this drug that could contribute with its calcium channel blocking effect to the diminished mechanical tension observed in the presence of the drug.Acknowledgments. We thank A. Losavio and M. Stefanolo for technical assistance. This work was supported by grants from CONICET and SUBCYT, Buenos Aires, Argentina and Muscular Dystrophy Association, USA.     

光通信系统中相干暗孤子间的相互作用

利用最小作用量原理导出非线性Schrodinger方程两个相干暗孤子之间的相互作用，它作为孤子间距△和初位相差θ的函数，随△的增大而指数地衰减，当两个孤子之间初位相差θ＜π/2时相互排斥，θ＝π/2时几科不存在相互作用。θ＞π/2时相互吸引，本也研究了高阶色散效应对相互作用的影响。     

Effects of nitric oxide on the contraction of skeletal muscle

A review of the literature suggests that the effects of nitric oxide (NO) on skeletal muscles fibers can be classified in two groups. In the first, the effects of NO are direct, due to nitrosation or metal nitrosylation of target proteins: depression of isometric force, shortening velocity of loaded or unloaded contractions, glycolysis and mitochondrial respiration. The effect on calcium release channels varies, being inhibitory at low and stimulatory at high NO concentrations. The general consequence of the direct effects of NO is to ‘brake’ the contraction and its associated metabolism. In the second group, the effects of NO are mediated by cGMP: increase of the shortening velocity of loaded or unloaded contractions, maximal mechanical power, initial rate of force development, frequency of tetanic fusion, glucose uptake, glycolysis and mitochondrial respiration; decreases of half relaxation time of tetanus and twitch, twitch time-to-peak, force maintained during unfused tetanus and of stimulus-associated calcium release. There is negligible effect on maximal force of isometric twitch and tetanus. The general consequence of cGMP-mediated effects of NO is to improve mechanical and metabolic muscle power, similar to a transformation of slow-twitch to fast-twitch muscle, an effect that we may summarize as a ‘slow-to-fast’ shift.