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51.
Y. Ikemoto S. Demura S. Yamaji M. Minami M. Nakada M. Uchiyama 《Sport Sciences for Health》2007,2(2):64-70
Although explosive isometric contraction provides little work toward the outside, force-time parameters of the rising phase
of the force-time curve may be able to predict muscle power. The purpose of this study was to examine the relationship between
muscle power with work (power grip) and force-time parameters during the rising phase in explosive isometric grip. Fifteen
healthy young adult males participated in this study. Power grip was measured using loads of 20%–50% of maximal voluntary
contraction (MVC) (peak isometric force). Subjects pulled explosively on a grip bar held with the second digital joints without
the thumb. Peak power was calculated from peak velocity and load. Explosive isometric grip was measured using a hand dynamometer.
Time-series data of both tests were sampled by an analog-to-digital interface. Both tests were performed with the subjects
seated with a sagittal and horizontal position of the arm supported by an armrest. Peak power in the power grip test tended
to be larger with an increase of the load, but there was no significant difference between 40% and 50% MVC. Only the peak
power in 50% MVC significantly correlated with peak grip force (r=0.52, p<0.05). The force-time parameters related to the peak rate of the rising force phase in explosive isometric grip significantly
correlated with the peak powers (30%–50% MVC, r=|0.58−0.78|). Peak rate of the rising force phase in explosive isometric grip
may be useful for predicting muscle power with loads between 30%–50% MVC. 相似文献
52.
53.
Health policy, epidemiology and power: the interest web 总被引:4,自引:4,他引:0
The relation between epidemiological research results and policy-making is reviewed. Apparently, traditional models of policy-making(incrementalism, mixed scanning synoptic planning) do not explainwhy research findings are hardly used in policy-making procedures. It is suggested that this phenomenon is related to three determinantsof policy-making: (i) a bias stemming from sets of causal, finaland normative assumptions and presuppositions; (ii) interestwebs of groups in certain domains; and (iii) the power of organizationsto monitor and communicate. The conclusion is that epidemiologistsshould engage in the policy-making process more consciouslyand conscientiously. 相似文献
54.
A. J. Bullock R. A. Duquette N. Buttell S. Wray 《Pflügers Archiv : European journal of physiology》1998,435(4):575-577
Intracellular pH (pHi) is known to modulate contraction. Neonatal tissues can differ from adult tissue in contractile response to stimuli known
to alter pHi e.g. hypoxia. Changes of pH are attenuated by buffering, thus any difference in buffering power (β) between tissues could
affect their functional response to pHi perturbation. Similarly the extent to which any extracellular pH (pHo) alteration is transmitted into a pHi change will also influence function. We have therefore determined the intrinsic β and effect of pHo change on pHi in neonatal and adult ureteric, uterine and gastric smooth muscles using the pH-sensitive fluorophore carboxy-SNARF. β was
found to be similar in the three adult tissues, but there were significant differences between neonatal tissues. In contrast,
we found little difference in the amount of pHi change produced by pHo change between neonatal and adult tissues from the same smooth muscle, but a difference between smooth muscles. These data
highlight significant differences between smooth muscles and their developmental state, which may contribute to different
degrees of protection when pH is perturbed.
Received: 17 October 1997 / Received after revision: 27 November 1997 / Accepted: 28 November 1997 相似文献
55.
血流频谱分析在乳腺肿块鉴别诊断中的价值 总被引:3,自引:0,他引:3
目的:检验血流频谱分析在鉴别乳腺原发性肿块良恶性方面的价值并确立最佳的数值标准。方法:使用彩色多普勒血流显像和能量多普勒显像分别引导脉冲多普勒频谱分析,检查了104例乳腺原发性包块(良性55例63个病灶,恶性49例64个病灶),测量指标包括肿块周边与内部血流收缩期峰速、搏动指数及阻力指数,并分别绘制受试者工作曲线确定各自的最佳阈值。结果,以CDFI状态取频谱,乳癌病灶周边及内部血流的平均PSV,P 相似文献
56.
Wheezing at 8 and 13 years: changing importance of bronchiolitis and passive smoking 总被引:2,自引:0,他引:2
A group of 153 children (51 with a history of bronchiolitis and 102 matched controls) were evaluated in a historical cohort study at a mean age of 8 years and again at 13 years to test the primary hypothesis that mild bronchiolitis, far more common than severe (hospitalized) bronchiolitis, predicts wheezing. A secondary hypothesis was that passive smoking also predicts wheezing. Many potentially confounding variables such as family history of asthma were controlled in analyses. Analysis at 13 years produced results that were not anticipated from previous analysis of interviews at age 8. Although mild bronchiolitis was a powerful predictor of wheezing at age 8 years, it was no longer a strong predictor of wheezing at age 13 in either bivariate or multivariate analysis. Although epidemiologic studies, by their nature, cannot prove causality, findings are consistent with the hypothesis that sequelae often follow mild bronchiolitis but diminish during childhood. Maternal smoking was a powerful predictor of wheezing at age 13 in bivariate analysis (Kendall's Tau B = 0.19, P less than 0.01) and in multivariate analysis (odds ratio = 2.67, P less than 0.01). In children at highest risk for wheezing, males with a family history of asthma, multivariate analysis suggested that maternal smoking is associated with an increase in wheezing from 36% to 60%. We conclude that passive smoking, previously identified as a risk factor in this population for both bronchiolitis in infancy and wheezing at age 8, is a risk factor for wheezing-associated morbidity throughout the childhood years. 相似文献
57.
Hans Brunner Thomas C Wetter Birgit Hogl Alexander Yassouridis Claudia Trenkwalder Elisabeth Friess 《Movement disorders》2002,17(5):928-933
We investigated non-rapid eye movement (non-REM) sleep in patients with newly diagnosed Parkinson's disease (PD) who had never previously received dopaminergic medication. There were no significant differences in the conventional sleep parameters between de novo patients with PD and a healthy control group, but the length of stage 1 sleep and the number of awakenings increased significantly upon administration of dopaminergic drugs. Analyzing the quantitative electroencephalogram (EEG), we observed a significant reduction in the low-delta frequency range and a nonsignificant increase in the sigma frequency range in de novo patients with PD. The dopaminergic medication also nonsignificantly reduced the low-delta and sigma frequencies, the latter to the level of the controls. Possible mechanisms that may account for the observed differences are discussed. It is suggested that Parkinson's disease as well as the application of dopaminergic drugs exerts a desynchronizing effect on the sleep EEG that is reflected in a disruption of sleep continuity. 相似文献
58.
Sixty-two cases of breast pathology were randomly selected from the files of the Dunedin Public Hospital for evaluation of mean epithelial nuclear volume. The cases were comprised of both benign and malignant ductal epithelial disease, diagnosed in cytological smears or in histological sections. Nuclear volume in histological preparations was estimated by the stereological technique of point-line intercept measurements to derive volume-weighted mean volumes (vV). An index of the nuclear volume (Vi) of cytology smears was calculated from measurements of nuclear areas by either image analysis Vi(e) or point-line intercepts Vi(p). By all methods of analysis a clear distinction of nuclear volume was found between the benign [means for the cytology were 148 microns 3 (Vi(e)) or 246 microns 3 (Vi(p)), and 203 microns 3 (Vv) for the histology specimens] and malignant diseased cases [means for cytology: 524 microns 3 (Vi(e)) or 886 microns 3 (Vi(p)), and 587 microns 3 (vV) for the histology specimens]. 相似文献
59.
60.
核因子kappa B(NF—κB)是许多促炎因子高表达所必需的转录因子。近年来,随着分子生物学技术的发展,NF—κB对免疫、应激和炎症反应以及淋巴细胞分化和生长的调控作用成为研究的热点。作者就NF—κB在缺血-再灌注及体外循环损伤机制中的作用作一综述,并简要介绍阻断NF-κB激活干预治疗的研究进展。 相似文献