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排序方式: 共有912条查询结果,搜索用时 25 毫秒
21.
蒋光海 《武汉体育学院学报》2004,38(3):45-47,51
采用实验法与统计分析法,分析了我国拳击运动员在冬训上量阶段血清肌酸激酶、血尿素氮和血红蛋白的变化,以此来评定运动员的机能水平,并提出相应的建议。结果表明。血红蛋白与血尿素氮结合使用,能较准确地评定拳击运动员的身体机能状况,血清肌酸激酶能有效评定周期训练后肌肉所受的刺激程度。提出了适当的训练调整计划,以利于运动员下一阶段训练的顺利进行。 相似文献
22.
热休克蛋白是生物体在不利环境因素刺激下应激合成的一组特殊的蛋白质.实验表明,经过预应激处理后,生物机体对再次热休克或其它应激刺激产生耐受;而其它应激刺激作用于机体后,亦使其获得对热休克的耐受.因此,在对相关研究综述的基础上,提出通过HSP70途径来提高肝脏抗氧化能力,避免或减小大强度运动对肝脏的损伤. 相似文献
23.
24.
带阶梯栅氧的N-LDMOS晶体管热载流子退化分析(英文) 总被引:1,自引:0,他引:1
为了减小高压N-LDMOS器件的热载流子效应并维持其开态特性,提出了一种带有阶梯栅氧的新型N-LDMOS器件结构.与传统的N-LDMOS器件相比,其栅极下方Si-SiO2界面处的电场强度明显减弱,因而可以有效地减少器件的热载流子效应,而该阶梯栅氧结构可以通过功率集成电路工艺中普遍采用的栅氧生长方法进行2次栅氧生长来获得.采用TCAD仿真技术对传统的N-LDMOS器件和所提出的新型N-LDMOS器件的热载流子退化现象进行了对比和分析,并在维持原有器件特性参数的基础上得出了新型N-LDMOS器件中厚栅氧部分的最优长度.最后,通过选取某些特性参数进行了实际的器件退化测试,结果表明该新型N-LDMOS器件的热载流子退化现象得到了很大的改善. 相似文献
25.
Yi-Feng Wang Chunqiu Zhang Keni Yang Yufei Wang Shaobo Shan Yan Yan Kenneth A Dawson Chen Wang Xing-Jie Liang 《国家科学评论(英文版)》2021,8(6)
Liposomes, especially cationic liposomes, are the most common and well-investigated nanocarriers for biomedical applications, such as drug and gene delivery. Like other types of nanomaterials, once liposomes are incubated in a biological milieu, their surface can be immediately cloaked by biological components to form a protein corona, which confers a new ‘biological identity’ and modulates downstream interactions with cells. However, it remains unclear how the protein corona affects the transportation mechanism after liposomes interact with cells. Here, we employed home-made aggregation-induced-emission-visualized nanoliposomes TR4@Lipo as a model to investigate transportation with or without the protein corona by optical imaging techniques. The results show that the protein corona can change the cellular transportation mechanism of TR4@Lipo from energy-independent membrane fusion to energy-dependent endocytosis. The protein corona also modulates the intracellular distribution of loaded cargoes. This knowledge furthers our understanding of bio-nano interactions and is important for the efficient use of cationic liposomes. 相似文献
26.
以Na2WO4·2H2O和HCl为原料,采用水热法合成了WO3,并用x射线粉末衍射(XRD)、扫描电镜(SEM)、紫外漫反射(uV—Vis)、电子能量分散谱(EDS)和激光拉曼光谱(Raman)测试手段对样品进行表征。测试结果表明,Na2SO4作为添加剂时水热合成的产物皆为六方相三氧化钨纳米线,其粗细和长短略有差异,不同浓度的Na2SO4对产品晶型和形貌无影响,但影响其晶粒尺寸,其中0.125MNa2SO4所得六方相WO3纳米线的尺寸最小,平均直径约为5nm,长度约为1um,并具有最佳的光催化活性,可见光(≥420nm)照射150min罗丹明B溶液后的降解率达96.01%。 相似文献
27.
《文物保护研究》2013,58(2):117-128
AbstractA system for continuous monitoring of atmospheric corrosivity has been developed. An electronic unit measures and records changes in the electrical resistance of a thin metal track applied on an insulating substrate. If the metal corrodes, the effective cross sectional area of the track decreases and the electrical resistance increases. Sensors made of silver, copper, iron/steel, zinc, lead, tin, aluminium, bronze, and brass at thicknesses from 50 nm to 250 µm were tailored for environments with different corrosivities. The developed technology proved capable of providing high sensitivity, allowing for real-time corrosion monitoring even in low-corrosive indoor cultural heritage facilities. Laboratory tests showed good reproducibility with the standard deviation of parallel measurements at less than ±20% for metals which corrode uniformly in the tested environments. Several examples selected from a broad testing programme in partner museums, libraries, and other institutions show successful applications of the logger system for characterization of air quality control in indoor locations, during transport and in temporary exhibitions; assessment of new buildings and storage facilities; and fundamental studies of optimal conservation and storage procedures. A first outline of a classification system for lead, which is particularly sensitive to the presence of carboxylic acids, is given. The technique has a large potential as an independent method for monitoring air quality in facilities displaying and storing valuable objects of cultural heritage. 相似文献
28.
Building muscle: nutrition to maximize bulk and strength adaptations to resistance exercise training
《European Journal of Sport Science》2013,13(2):67-76
Abstract Several nutritional strategies can optimize muscle bulk and strength adaptations and enhance recovery from heavy training sessions. Adequate energy intake to meet the needs of training and carbohydrate intake sufficient to maintain glycogen stores (>7 g carbohydrate·kg?1·day?1 for women; >8 g carbohydrate·kg?1·day?1 for men) are important. Dietary protein intake for top sport athletes should include some foods with high biological value, with a maximum requirement of approximately 1.7 g·kg?1·day?1 being easily met with an energy sufficient diet. The early provision of carbohydrate (>1 g·kg?1) and protein (>10 g) early after an exercise session will enhance protein balance and optimize glycogen repletion. Creatine monohydrate supplementation over several days increases body mass through water retention and can increase high-intensity repetitive ergometer performance. Creatine supplementation can enhance total body and lean fat free mass gains during resistance exercise training; however, strength gains do not appear to be enhanced versus an optimal nutritional strategy (immediate post-exercise protein and carbohydrate). Some studies have suggested that β-OH-methyl butyric acid (β-HMB) can enhance gains made through resistance exercise training; however, it has not been compared “head to head” with optimal nutritional practices. Overall, the most effective way to increase strength and bulk is to perform sport-specific resistance exercise training with the provision of adequate energy, carbohydrate, and protein. Creatine monohydrate and β-HMB supplementation may enhance the strength gains made through training by a small margin but the trade-off is likely to be greater bulk, which may be ergolytic for any athlete participating in a weight-supported activity. 相似文献
29.
《European Journal of Sport Science》2013,13(7):931-940
AbstractAging has been related with a decline in the ability to handle protein folding, which leads to endoplasmic reticulum stress and alterations in unfolded protein response (UPR). Importantly, physical activity could activate the UPR and attenuate or prevent age-induced endoplasmic reticulum (ER) dysfunction. The current study evaluated the effects of a resistance exercise on UPR and mitochondrial functions in peripheral blood mononuclear cells (PBMCs) from elderly subjects. Thirty healthy women and men (age, 72.8, sx??=?2.2 years) were randomized to a training group, which performed an 8-week resistance training programme, or a control group, which followed their daily routines. The phosphorylation of PERK and IRE1, as well as ATF4, and XBP1 protein expression, significantly increased following the training, while expression of BiP, AFT6 and CHOP remain without changes. Additionally, the intervention also induced an increase in PGC-1α and Mfn1 protein levels, while no changes were found in Drp1 expression. Finally, the resistance protocol was not able to activate PINK1/Parkin and Bnip3/Nix pathways. The results obtained seem to indicate that 8-week resistance exercise activates the UPR, stimulates mitochondrial biogenesis, maintains mitochondrial dynamics and prevents mitophagy activation by unfolded proteins in PBMCs from elderly subjects. 相似文献
30.
衰老的机制到目前为止没有确切的理论解释,许多研究表明衰老与HSP70的关系密切.论文对HSP70与衰老之间的相互影响及其机制等方面进行了综述,并着重探讨了运动诱导的HSP70对衰老机体的作用,以期为运动延缓衰老提供有力的理论依据. 相似文献