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根据胶原生物矿化的原理和方法,制备不同条件下的明胶生物矿化样品,通过红外光谱分析,发现磷酸钙、氯化镁的存在引起明胶分子中酰胺Ⅰ、Ⅱ、Ⅲ带显著褪化,明胶生物矿化与胶原生物矿化的紫外光谱曲线也有相似之处,表明明胶与钙、镁离子存在配位作用,明胶也可能作为生物矿化的模板材料。 相似文献
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Fitnessgram® is a digital platform designed to help physical education teachers measure, record, disseminate and analyse the results of school-based student fitness testing. Despite important questions about the ethics, educational value and costs of Fitnessgram®, it is now widely used in the United States and is spreading to other countries. In this empirically investigative study, we draw on academic studies and commentary, media stories, government and funding body reports, press releases and advertisements to describe the emergence of Fitnessgram® and the convergence of factors that appear to guarantee the programme’s increasing ubiquity. We also discuss the various ways the data sets built by Fitnessgram® may reshape the practice and purpose of physical education as well how young people understand their own health in light of this. In the face of puzzling academic silence on the Fitnessgram® phenomena, this paper stimulates lines of critical academic enquiry about the financial self-interest, educational shortcomings and policy implications that its rise suggests. 相似文献
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羌族文化被史学界称为＂中国的玛雅文化＂,本文将羌族文化的基本形态作了系统的梳理,并将其归纳为羌语、释比文化、萨朗文化、工艺（技艺）文化、艺体文化、宗教文化、习俗文化、传说文化以及岷江上游古文明与古蜀文化九个主要方面,阐述了各种表现形态的基本特点,指出了羌族文化保护中值得注意的倾向性问题。 相似文献
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The aim of this study was to assess the effect of the recovery duration in intermittent training drills on metabolism and coordination in sport games. Ten nationally ranked male tennis players (age 25.3±3.7 years, height 1.83±0.8 m, body mass 77.8±7.7 kg; mean ±s x ) participated in a passing-shot drill (baseline sprint with subsequent passing shot) that aimed to improve both starting speed and stroke quality (speed and precision). Time pressure for stroke preparation was individually adjusted by a ball-machine and corresponded to 80% of maximum running speed. In two trials (T10, T15) separated by 2 weeks, the players completed 30 strokes and sprints subdivided into 6 2 5 repetitions with a 1 min rest between series. The rest between each stroke-and-sprint lasted either 10 s (T10) or 15 s (T15). The sequence of both conditions was randomized between participants. Post-exercise blood lactate concentration was significantly elevated in T10 (9.04±3.06 vs 5.01±1.35 mmol·l-1, P ? 0.01). Running time for stroke preparation (1.405±0.044 vs 1.376±0.045 s, P ? 0.05) and stroke speed (106±12 vs 114±8 km·h-1, P ? 0.05) were significantly decreased in T10, while stroke precision - that is, more target hits ( P ? 0.1) and fewer errors (P ? 0.05) - tended to be higher. We conclude that running speed and stroke quality during intermittent tennis drills are highly dependent on the duration of recovery time. Optimization of training efficacy in sport games (e.g. combined improvement of conditional and technical skills) requires skilful fine-tuning of monitoring guidelines. 相似文献
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The effect of recovery duration on running speed and stroke quality during intermittent training drills in elite tennis players 总被引：3，自引：1，他引：2
The aim of this study was to assess the effect of the recovery duration in intermittent training drills on metabolism and coordination in sport games. Ten nationally ranked male tennis players (age 25.3+/-3.7 years, height 1.83+/-0.8 m, body mass 77.8+/-7.7 kg; mean +/- sx) participated in a passing-shot drill (baseline sprint with subsequent passing shot) that aimed to improve both starting speed and stroke quality (speed and precision). Time pressure for stroke preparation was individually adjusted by a ball-machine and corresponded to 80% of maximum running speed. In two trials (T10, T15) separated by 2 weeks, the players completed 30 strokes and sprints subdivided into 6 x 5 repetitions with a 1 min rest between series. The rest between each stroke-and-sprint lasted either 10 s (T10) or 15 s (T15). The sequence of both conditions was randomized between participants. Post-exercise blood lactate concentration was significantly elevated in T10 (9.04+/-3.06 vs 5.01+/-1.35 mmol x l(-1), P < 0.01). Running time for stroke preparation (1.405+/-0.044 vs 1.376+/-0.045 s, P < 0.05) and stroke speed (106+/-12 vs 114+/-8 km x h(-1), P < 0.05) were significantly decreased in T10, while stroke precision - that is, more target hits (P < 0.1) and fewer errors (P < 0.05) - tended to be higher. We conclude that running speed and stroke quality during intermittent tennis drills are highly dependent on the duration of recovery time. Optimization of training efficacy in sport games (e.g. combined improvement of conditional and technical skills) requires skilful fine-tuning of monitoring guidelines. 相似文献
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