Epigenetic regulation by polycomb group complexes: focus on roles of CBX proteins     

Rong-gang MA  Yang ZHANG  Ting-ting SUN  Bo CHENG 《Journal of Zhejiang University. Science. B》2014,15(5):412-428

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基于SVDD的航空发动机主轴轴承性能退化状态评估     

佟佩声  左洪福  李梦莹  张营  刘若晨 《滨州师专学报》2014,(3):28-32

静电监测技术以其优越的早期故障发现能力为航空发动机主轴轴承的状态监测提供了一种有效手段,但是单一特征参数对轴承全寿命状态反应存在不一致或不灵敏,针对这一问题,提出一种基于支持向量描述（SVDD）的静电监测多特征参数融合评估方法。首先通过主元分析将高维数据进行简化处理,实现数据从高维到低维的转化,然后建立正常状态的支持向量描述基准模型,以测试数据与基准模型的距离作为反映轴承性能退化的量化指标,并与振动监测进行了对比。实验表明,所提方法能够更有效反映轴承性能退化状态的变化。  相似文献   

不同色泽大豆蛋白分离得率的比较     

卜婷 《蒙自师范高等专科学校学报》2014,(5):19-20

碱溶法提取具有色泽差异的不同种类大豆蛋白后,考马斯亮蓝法测定粗提液的蛋白质含量,丙酮抽提并干燥制得大豆蛋白干粉,微量凯氏定氮法测定干粉中的蛋白质含量并进行比较,确定蛋白含量及蛋白得率最高的大豆类型.结果表明不同色泽的大豆蛋白质含量不同,绿色大豆的蛋白可溶性及蛋白含量较高,但蛋白干粉得率较低.  相似文献   

玉米秸秆及纤维素高值化应用的研究进展     

王犇  潘高峰  黄科林 《大众科技》2014,(12)

文章从玉米产业废弃物玉米秸秆的应用出发,对玉米秸秆从传统方面进行总结,对玉米秸秆纤维素从降解、再生和制备吸附材料三个角度进行高值化应用的综述。  相似文献   

Blood flow restriction reduces time to muscular failure     

《European Journal of Sport Science》2013,13(3):238-243

Abstract

Exercise to failure results in similar muscle protein synthesis responses, independent of intensity. However, low-intensity exercise likely requires more repetitions and individuals with injuries may be incapable of sustaining the mechanical stress to reach failure. The aim of this study was to determine if knee wraps provide a stimulus to decrease time to failure. Twenty healthy individuals participated in a randomized crossover study consisting of three trials. The first trial was used to determine one-repetition maximum (1-RM) on leg extension. Participants were then assigned to a blood flow restriction or control group. After trial 2, participants crossed over to the opposite trial. Knee wraps were placed around the upper thigh of each leg during blood flow restriction. Leg extensions were completed at 30% 1-RM until failure. A rating of perceived exertion was taken after exercise and whole blood samples were taken before, after, and 3 min after exercise for the determination of lactate. Repetitions until failure and total work were significantly lower with practical blood flow restriction compared with the control trial. Metabolic stress as measured by whole blood lactate was higher immediately after muscular failure in the control compared with the blood flow restriction trial, but not so 3 min after exercise. There were no differences in ratings of perceived exertion. In conclusion, knee wraps provide a stimulus for blood flow restriction allowing failure to occur sooner with similar metabolic stress after reperfusion. However, similar perceptual responses despite the lower workload with blood flow restriction may limit its application to the highly motivated.  相似文献   

Muscle damage and soreness following a 50-km cross-country ski race     

《European Journal of Sport Science》2013,13(1):27-33

Abstract

In this study, we examined indirect markers of muscle damage and muscle soreness following a 50-km cross-country ski race completed in 2 h and 57 min to 5 h and 9 min by 11 moderately trained male university students. Maximal strength of the knee extensors, several blood markers of muscle damage and inflammation, and muscle soreness (visual analog scale: 0 = “no pain”, 50 mm = “unbearably painful”) were measured one day before, immediately after, and 24, 48, 72, and 144 h after the race. Changes in the measures over time were analysed using one-way repeated-measures analysis of variance and a Fisher's post-hoc test. Maximal strength of the knee extensors decreased significantly (P<0.05) immediately after the race (mean ?27%, s=6), but returned to pre-exercise values within 24 h of the race. All blood markers increased significantly (P<0.05) following the race, peaking either immediately (lactate dehydrogenase: 253.7 IU · l^?1, s=13.3; myoglobin: 476.4 ng · ml^?1, s=85.5) or 24 h after the race (creatine kinase: 848.0 IU · l^?1, s=151.9; glumatic oxaloacetic transaminase: 44.3 IU · l^?1, s=4.2; aldolase: 10.0 IU · l^?1, s=1.3; C-reactive protein: 0.36 IU · l^?1, s=0.08). Muscle soreness developed in the leg, arm, shoulder, back, and abdomen muscles immediately after the race (10–30 mm), but decreased after 24 h (<15 mm), and disappeared 48 h after the race. These results suggest that muscle damage induced by a 50-km cross-country ski race is mild and recovery from the race does not take long.  相似文献   

The response of intracellular signaling and muscle-protein metabolism to nutrition and exercise     

《European Journal of Sport Science》2013,13(3):107-121

Abstract

In recent years, a body of literature examining the response of muscle-protein metabolism to exercise and nutrition has arisen. Developments in methods, especially stable isotopic tracer methodology, have allowed much information to be gathered in vivo in humans. The metabolic mechanism behind increased muscle mass requires that muscle-protein synthesis exceeds breakdown, i.e., net muscle-protein synthesis. Increased net muscle-protein balance may occur due to exercise, but net synthesis may occur only with the addition of nutrients, particularly a source of amino acids. The major impact of increased amino acid availability on net muscle-protein balance is due to stimulation of muscle-protein synthesis and less to inhibition of muscle-protein breakdown. Amino acids seem to stimulate muscle-protein synthesis, not only by mass action, i.e., providing substrate, but also as signals for initiation of protein synthesis. Stimulation of muscle-protein synthesis by amino acid ingestion may be linked to increased intracellular amino acid levels and/or to changing amino acid levels in the blood. Carbohydrate ingestion, most likely through the action of insulin, also may play a role in the response of muscle to exercise and nutrition. There is very little research in humans in vivo on the intracellular signaling that is linked to muscle-protein synthesis. It is clear that intracellular signaling responds to both insulin and amino acids, but the interactions with exercise are not well known; however, the details of the pathways have only just begun to be investigated, especially in humans. Delineation of these pathways is complicated, and there is little doubt that multiple intracellular signaling pathways with several levels of communication are involved in the hypertrophy process in response to nutrition and exercise. A systematic investigation of the relationship of the signaling to insulin and amino acids combined with exercise will provide important information, especially for populations vulnerable to muscle loss.  相似文献   

白腐真菌对低阶煤模型化合物喹啉降解机理研究     

石开仪  陶秀祥  籍永华  任强  舒伟  严毅 《六盘水师范高等专科学校学报》2013,(4):53-55

白腐真菌在低阶煤炭深加工方面有很大的应用潜力。为依据低阶煤降解机理,报道以喹啉作为低阶煤含氮模型化合物,利用白腐真菌在DOX培养基中对其进行微生物降解,通过测定降解体系中木质素过氧化物酶(LiP)、锰过氧化物酶(MnP)、漆酶(Lac)和多酚氧化酶(PPO)的活性,并利用红外光谱仪、气相色谱-质谱分析仪分析了降解产物。结果发现,喹啉在Lac、LiP和PPO等共同催化下发生了羟基化、醌基化、开环、C-N断裂、氧化等作用,得到对应的8种主要降解产物,从而推测出白腐真菌对喹啉的降解历程。  相似文献   

Conference communications     

Kevin D Tipton  Robert R Wolfe 《Journal of sports sciences》2013,31(1):65-84

The main determinants of an athlete's protein needs are their training regime and habitual nutrient intake. Most athletes ingest sufficient protein in their habitual diet. Additional protein will confer only a minimal, albeit arguably important, additional advantage. Given sufficient energy intake, lean body mass can be maintained within a wide range of protein intakes. Since there is limited evidence for harmful effects of a high protein intake and there is a metabolic rationale for the efficacy of an increase in protein, if muscle hypertrophy is the goal, a higher protein intake within the context of an athlete's overall dietary requirements may be beneficial. However, there are few convincing outcome data to indicate that the ingestion of a high amount of protein (2–3?g?·?kg^?1 BW?·?day^?1, where BW?=?body weight) is necessary. Current literature suggests that it may be too simplistic to rely on recommendations of a particular amount of protein per day. Acute studies suggest that for any given amount of protein, the metabolic response is dependent on other factors, including the timing of ingestion in relation to exercise and/or other nutrients, the composition of ingested amino acids and the type of protein.  相似文献   

退化森林生态系统恢复评价分析     

陈开伟  商志伟 《湖北第二师范学院学报》2012,(8):100-102

森林退化,已经成为一个世界性的难题。森林资源,能够为人们的生活提供必须的资源和原料,能够对空气进行持续净化,并起到了保持水土的作用。然而,大面积的采伐导致了森林面积的大幅度减少,造成了土地沙化等一系列环境问题,使得森林退化问题成为人类必须解决的严峻问题,也使得退化森林生态系统恢复评价成为可靠的参考数据。本文就我国森林生态系统恢复评价展开分析,并对于森林资源的保护工作提出了相关建议,希望对于我国森林退化问题的解决起到一定的借鉴性作用。  相似文献