Blood flow restriction in human skeletal muscle during rest periods after high-load resistance training down-regulates miR-206 and induces Pax7

BackgroudBlood flow restriction (BFR) with low-intensity resistance training has been shown to result in hypertrophy of skeletal muscle. In this study, we tested the hypothesis that BFR during the rest periods between acute, high-intensity resistance exercise sessions (70% of 1 repetition maximum, 7 sets with 10 repetitions) enhances the effects of the resistance training.MethodsA total of 7 healthy young men performed squats, and between sets BFR was carried out on one leg while the other leg served as a control. Because BFR was applied during rest periods, even severe occlusion pressure (approximately 230 mmHg), which almost completely blocked blood flow, was well-tolerated by the participants. Five muscle-specific microRNAs were measured from the biopsy samples, which were taken 2 h after the acute training.ResultsDoppler data showed that the pattern of blood flow recovery changed significantly between the first and last BFR. microRNA-206 levels significantly decreased in the BFR leg compared to the control. The mRNA levels of RAC-β serine/threonine-protein kinase v22, nuclear respiratory factor 1, vascular endothelial growth factor, lupus Ku autoantigen protein p70 genes (p < 0.05), and paired box 7 (p < 0.01) increased in the BFR leg. The protein levels of paired box 7, nuclear respiratory factor 1, and peroxisome proliferator-activated receptor γ coactivator 1α did not differ between the BFR leg and the control leg.ConclusionBFR, during the rest periods of high-load resistance training, could lead to mRNA elevation of those proteins that regulate angiogenesis, mitochondrial biogenesis, and muscle hypertrophy and repair. However, BFR also can cause DNA damage, judging from the increase in mRNA levels of lupus Ku autoantigen protein p70.     

管式电除尘器本体电阻特性的分析

以水泥工业普通回转窑无尘烟气为例,提出了管式电除尘器本体静态电阻、动态电阻概念,并对本体静态电阻、动态电阻随工况烟气成分的浓度,温度、压力的改变而呈现的变化规律进行研究.     

145份小麦品种(系)的赤霉病抗性评价

采用土表接种的方法,对145份适合于淮河流域种植的小麦品种(系)进行了赤霉病的抗性鉴定和评价。以病小穗率为指标,与株高、穗长、旗叶长和旗叶宽等农艺性状做了相关性分析。结果表明,能够直接应用于大田生产的赤霉病抗性品种比较匮乏,145份材料中没有发现达到免疫和抗病水平的品系,2份达到中抗水平,46份材料表现为中感,10份材料介于中感至感病之间,87份材料表现为感病。从材料地理来源上看,仅有来自江苏的种质存在较好的抗病基因资源,而山东、安徽和河南地区的小麦品系普遍缺乏抗病性。相关性分析显示,病小穗率与株高极显著负相关,与旗叶长和旗叶宽极显著正相关,感病性的降低和丰产性的提高存在矛盾。     

不同玉米杂交种茎腐病抗性比较研究

为了筛选对茎腐病抗性较强、产量较高的玉米杂交种,采用人工接种法研究了不同玉米杂交种对茎腐病抗病性和产量结构变化。结果表明,不同玉米杂交种对茎腐病的抗性差异较大。其中,杂交种3号达中抗（MR）,其它均为感（S）或高感（HS）;接种玉米茎腐病菌的杂交种和未接种的穗长、穗粗、行粒数、单穗重、单穗粒重和百粒重之间差异显著（P〈0．05）,而对秃顶长度、粒行数的影响不显著（P〉0．05）。杂交种3号的产量最高,明显高于郑单958,是较为理想的抗病高产新组合。     

循环经济下企业组织创新阻力分析与对策研究

循环经济已经成为社会经济发展的必然趋势。为了适应循环经济的要求,企业就要进行企业组织创新。分析了循环经济下企业创新可能遇到的阻力,通过建立创新阻力评价指标体系,构建模糊评价矩阵,并对循环经济下企业组织创新阻力的解决策略进行了相关研究。     

Effects of coffee and caffeine anhydrous on strength and sprint performance

Caffeine and coffee are widely used among active individuals to enhance performance. The purpose of the current study was to compare the effects of acute coffee (COF) and caffeine anhydrous (CAF) intake on strength and sprint performance. Fifty-four resistance-trained males completed strength testing, consisting of one-rep max (1RM) and repetitions to fatigue (RTF) at 80% of 1RM for leg press (LP) and bench press (BP). Participants then completed five, 10-second cycle ergometer sprints separated by one minute of rest. Peak power (PP) and total work (TW) were recorded for each sprint. At least 48 hours later, participants returned and ingested a beverage containing CAF (300?mg flat dose; yielding 3–5?mg/kg bodyweight), COF (8.9?g; 303?mg caffeine), or placebo (PLA; 3.8?g non-caloric flavouring) 30 minutes before testing. LP 1RM was improved more by COF than CAF (p?=?.04), but not PLA (p?=?.99). Significant interactions were not observed for BP 1RM, BP RTF, or LP RTF (p?>?.05). There were no sprint?×?treatment interactions for PP or TW (p?>?.05). 95% confidence intervals revealed a significant improvement in sprint 1 TW for CAF, but not COF or PLA. For PLA, significant reductions were observed in sprint 4 PP, sprint 2 TW, sprint 4 TW, and average TW; significant reductions were not observed with CAF or COF. Neither COF nor CAF improved strength outcomes more than PLA, while both groups attenuated sprint power reductions to a similar degree. Coffee and caffeine anhydrous may be considered suitable pre-exercise caffeine sources for high-intensity exercise.     

糖尿病患者体内某些物质的变化

糖尿病是一种常见的复杂性疾病,发病原因既有遗传因素又有环境因素,属于多遗传基因。目前人类根据对糖尿病患者体内某些物质的变化进行了研究,发现了诸如下丘脑神经肽、c肽联合胰岛素、肿瘤坏死因子、瘦素等物质。在糖尿病患者体内这些物质的含量有的提高,而有的却发生了相应的下降．主要是对这几种物质进行介绍,以使人们能更加准确地了解糖尿病的发病机制,从而研制出能更加行之有效的治疗方法。     

Exploring tertiary English as a Foreign Language writing tutors’ perceptions of the appropriateness of peer assessment for writing

Despite the increasing volume of research in peer assessment for writing, few studies have been conducted to explore teachers’ perceptions of its appropriateness for writing instruction. It is essential to understand teachers’ perceptions of peer assessment as teachers play an important role in whether and how peer assessment is implemented in their instruction. The current study investigated tertiary English writing tutors’ perceptions of the appropriateness of peer assessment for English as a Foreign Language writing in China, where peer assessment has been increasingly discussed and researched but only occasionally used in teaching. The current study scrutinised the reasons behind its limited use via in-depth exploratory interviews with 25 writing tutors with different teaching backgrounds. The interview data showed tutors’ limited knowledge of peer assessment and unanimous hesitation in using it. The former was explained by insufficient instruction and training in peer assessment. The latter relates to the incompatibility of peer assessment with the examinations-oriented education system, learners’ low English language proficiency and learning motivation, and the conflict of peer assessment with the entrenched teacher-driven learning culture. Suggestions are made about training and engaging teachers to effectively use peer assessment in instruction.     

行政组织变革的阻力及其对策

针对行政组织变革的特点,重点讨论变革中存在的阻力,了解变革的规律及产生变革阻力的原因,如何克服变革中的阻力、减少变革中的负面效应,使行政组织变革工作顺利进行。     

可变负载非接触电能传输系统的无功功率补偿

为解决非接触电能传输系统中负载电阻变化会导致系统传输能力变化的问题,研究非接触电能传输系统在并联—串联拓扑下负载变化时无功功率的补偿问题.通过分析理想可变初级电容的可控性,提出用积分控制器对可控电抗器进行动态调节以完成负载变化时的无功功率补偿.数值仿真表明,该控制方案是可行的.