对体育运动中反应时的探讨与研究

通过观察专业运动员与业余练习者的反应时测验得出:专业运动员反应时不仅在安静状态比业余组短,而且在递增运动负荷时的反应时也都短于业余组。无论是反应时还是反应速度,专业组与业余组都存在一定的差异,因此体育运动能提高神经肌肉的反应性,促进灵敏素质的发展,增强机体适应能力。     

Predicting ground reaction forces in running using micro-sensors and neural networks

Measurement of ground reaction force (GRF) in running provides a direct indication of the loads to which the body is subjected at each foot-ground contact, and can provide an objective explanation for performance outcomes. Traditionally, the collection of three orthogonal component GRF data in running requires an athlete to complete a series of return loops along a laboratory based runway, within which a force platform is embedded, in order to collect data from a discrete footfall. The major disadvantages associated with this GRF data collection methodology include the inability to assess multiple consecutive foot contacts and the fact that measurements are typically confined to the laboratory. The objective of this research was to investigate the potential for wearable instrumentation to be employed, in conjunction with artificial neural network (ANN) and multiple linear regression (MLR) models, for the estimation of GRF in middle distance running. A modular wearable data acquisition system was developed to acquire in-shoe force (ISF) data. Matched data sets from wearable instrumentation (source data) and force plate (target data) records were collected from elite middle-distance runners under controlled laboratory conditions for the purposes of ANN and MLR model development (MD) and model validation (MV). In terms of statistical measures of prediction accuracy the MLR model was found to provide a superior level of accuracy for the prediction of the vertical and medio-lateral components of GRF and alternatively, the ANN model provided the most accurate predictions of the anterior-posterior component of GRF. The prediction accuracy of each component of GRF was found to be governed by the inherent signal variability, in which case the vertical and anterior-posterior components were more reliable and subsequently predicted significantly more accurately than the medio-lateral component. The emerging capability for obtaining continuous GRF records from wearable instrumentation has the potential to permit unprecedented quantification of training stress and competition demands in running.     

几个反应参数对SiO2纳米粒子最终粒径影响的探讨

研究了在低TEOS浓度和高TEOS浓度下, TEOS浓度、NH3浓度、H2O浓度对SiO2纳米粒子最终粒径的影响.发现,在低TEOS浓度下制备的粒子,单分散性较好,粒径偏大;在高TEOS浓度下制备的粒子,粒径较小,属于纳米级粒子.另外,在低TEOS浓度和高TEOS浓度下,NH3浓度、H2O浓度对最终粒径的影响有较大差异.     

对女子幼儿体操运动员四项心理特征的研究

对经过一定阶段体操训练的和未经训练的６岁幼儿进行了四项心理指标的测试与对比分析，结果证明，参加训练的幼儿各项心理指标明显高于未经训练的普通幼儿。通过综合成绩的评定与有关幼儿性格特征的调查统计，发现具有综合类性特征的幼儿较多，而且她们的成绩较好。     

地果黄酮类化合物的含量及抗氧化作用测定

采用三氯化铝比色法测定了地果中黄酮类化合物含量,并研究其对猪油的抗氧化作用,对羟自由基清除和超氧离子自由基的抑制作用.研究发现,地果的黄酮含量为0.004 mg/ml,提取液的抗氧化作用较强,对羟自由基的清除率90.24%,对超氧离子自由基的抑制率为50%.     

我国重点城市U13男子足球运动员的神经类型和反应时的研究

选取我国重点城市U13足球比赛的15支队伍中的206名男子运动员作为研究对象,对其神经类型和反应时进行了测定和分析,结果表明:参加我国重点城市U13足球比赛的运动员中有50％的运动员为优秀神经类型,适合于从事体育运动;13岁组和训练年限较多组中的优秀神经类型所占的比例较大,说明随着年龄的成熟和训练的深入,神经过程会得到优化;不同年龄、训练年限、神经类型的个体在反应时上无差异,选择反应时短的运动员并不能反映其具有较优秀的神经类型.     

Role of Nitric Oxide in Salmonella Infection

Nitric oxide (NO) derivative of l-arginine is an important signaling molecule that mediates a variety of essential physiological processes including vasodilation neurotransmission, and host cell defense. Many types of cells produce NO e.g., smooth muscle cell, endothelial cell, and leukocytes. Host defense functions are known for many bacterial and parasitic infections. In the present study we estimated the levels of serum NO in cases of salmonellosis and in controls. The nitric oxide was estimated by cadmium reduction method, Griess reaction. We observed that in controls the level of NO was (22 ± 2.06) μmol/l and in cases the level was (137.49 ± 29.84) μmol/l. The level of NO was significantly higher than controls (p < 0.001). The raised level of NO could be accounted for by host response to the infection. The host rapidly expresses iNOS, which in turn produces an excess amount of NO. Its cytotoxic effect is by its reactive nitrogen oxide derivative e.g., peroxynitrite. Apart from this it also has anti apoptotic functions. In future one can do follow up study of typhoid cases by bacterial culture.     

Angiotensin Converting Enzyme Gene Polymorphism and its Association with Hypertension in South Indian Population

Hypertension, a well known risk factor for various cardiovascular, peripheral vascular and renal events is an important public health challenge. Renin angiotensin system (RAS) being the most vital pathogenic mechanism of hypertension is mediated by a key component; the angiotensin converting enzyme (ACE). The present study was aimed to know the relationship of ACE gene polymorphism and the possible risk of development of hypertension in south Indian population. The study included 101 clinically diagnosed hypertensive patients without any associated disease condition and 81 age and sex matched apparently healthy controls. Genotyping was performed using a polymerase chain reaction, (PCR) amplification of the intron 16 fragment harboring the 287 bp Alu repeat sequence. Three possible genotypes D/D, I/I homozygous and I/D heterozygous were analyzed where the D/D genotypes corresponds to higher ACE levels (D-Deletion, I-Insertion). The PCR products were separated on 2 % agarose gel. Statistical analysis was performed using SPSS.15 software program. We found a significance in frequency of D/D genotype in the hypertensive patients compared to the control group (p = 0.0005, odd’s ratio = 4.157). This suggested that ACE (D/D) genotypes are more prone for the development of hypertension. This is relatively a pilot study; but nevertheless may assist in identifying the pathophysiological cause of hypertension.     

碱-硅酸反应和硫酸盐侵蚀复合作用下的混凝土耐久性

碱-硅酸反应(ASR)和硫酸盐侵蚀是影响混凝土耐久性的两个重要因素。目前,对于单一因素作用下混凝土劣化过程的研究已有诸多报道,但关于混凝土在碱-硅酸反应和硫酸盐侵蚀复合作用下的损伤失效过程及机理研究却很少。本文介绍了近年来国内外在碱-硅酸反应和硫酸盐侵蚀方面的研究现状,主要阐述了它们各自的膨胀机理和抑制措施。在对Grattan等人试验中得到的膨胀数据、X射线衍射图和扫描电子显微镜图进行分析的基础上,讨论了混凝土在这两种因素复合作用下可能出现的膨胀值变化和强度变化,并提出有效的抑制措施。     

Fenton催化氧化反应机理及影响因素研究进展

对Fenton催化氧化反应机理进行研究,对影响Fenton反应过程的因素,如H2O2投加量、催化剂(Fe2+)投加量、pH值、反应时间、反应温度等进行分析,为Fenton试剂应用提供依据。