In order to improve the production of human-like collagen III(HLC III)by fed-batch culture of recombinant Escherichia coli BL21,the Plackett-Burman and Box-Behnken design were applied to optimize the fermentation proc...In order to improve the production of human-like collagen III(HLC III)by fed-batch culture of recombinant Escherichia coli BL21,the Plackett-Burman and Box-Behnken design were applied to optimize the fermentation process parameters.Three variables(induction time,inoculum age and pH),which have significant effects on HLC III production,were selected from eight variables by Plackett-Burman design.With the regression coefficient analysis in the Box-Behnken design,a relationship between HLC III production and three significant factors was obtained,and the optimum levels of the three variables were as follows:induction time 3.2h,inoculum age 12.6 h and pH 6.7.The 3D response surface plots and 2D contour plots created by the Box-Behnken design showed that the interaction between induction time and pH and that between innoculum age and pH were significant.An average 9.68 g·L1HLC III production was attained in the validation experiment under optimized condition,which was 80%higher than the yield of 5.36 g·L1before optimization.展开更多
Purpose： This study aimed to investigate whether workload intensity modulates exercise-induced effect on reaction time （RT） performances, and more specifically to clarify whether cognitive control that plays a cruc...Purpose： This study aimed to investigate whether workload intensity modulates exercise-induced effect on reaction time （RT） performances, and more specifically to clarify whether cognitive control that plays a crucial role in rapid decision making is altered. Methods： Fourteen participants performed a Simon Task while cycling 20 min at a light （first ventilatory threshold, VT~ - 20%）, moderate （VTI）, or very hard （VTj ＋ 20%） level of exercise. Results： After 15 min of cycling, RTs are faster than during the first 5 min of exercise. This benefit does not fluctuate with the intensity of exercise and enlarges as RT lengthens. Despite a numerical difference suggesting a greater facilitation during moderate exercise （-16 ms） than during a light exercise （-10 ms）, the benefit is not statistically different. Interestingly, we did not observe any signs of worsening on RT or on accuracy during very hard exercise. Conclusion： Cognitive control is extremely robust and appears not to be affected by the intensity of exercise. The selective inhibition and the between-trials adjustments are effective from the beginning to the end of exercise, regardless of the workload output.展开更多
基金Supported by the National Natural Science Foundation of China（20776119） the National High Technology Research and Development Program of China（2007AA03Z456A） the Special Research Program of the Education Department of Shaanxi Province（07JK417）
文摘In order to improve the production of human-like collagen III(HLC III)by fed-batch culture of recombinant Escherichia coli BL21,the Plackett-Burman and Box-Behnken design were applied to optimize the fermentation process parameters.Three variables(induction time,inoculum age and pH),which have significant effects on HLC III production,were selected from eight variables by Plackett-Burman design.With the regression coefficient analysis in the Box-Behnken design,a relationship between HLC III production and three significant factors was obtained,and the optimum levels of the three variables were as follows:induction time 3.2h,inoculum age 12.6 h and pH 6.7.The 3D response surface plots and 2D contour plots created by the Box-Behnken design showed that the interaction between induction time and pH and that between innoculum age and pH were significant.An average 9.68 g·L1HLC III production was attained in the validation experiment under optimized condition,which was 80%higher than the yield of 5.36 g·L1before optimization.
基金supported by a grant from the French Research Agency (ANR 2013-069)
文摘Purpose： This study aimed to investigate whether workload intensity modulates exercise-induced effect on reaction time （RT） performances, and more specifically to clarify whether cognitive control that plays a crucial role in rapid decision making is altered. Methods： Fourteen participants performed a Simon Task while cycling 20 min at a light （first ventilatory threshold, VT~ - 20%）, moderate （VTI）, or very hard （VTj ＋ 20%） level of exercise. Results： After 15 min of cycling, RTs are faster than during the first 5 min of exercise. This benefit does not fluctuate with the intensity of exercise and enlarges as RT lengthens. Despite a numerical difference suggesting a greater facilitation during moderate exercise （-16 ms） than during a light exercise （-10 ms）, the benefit is not statistically different. Interestingly, we did not observe any signs of worsening on RT or on accuracy during very hard exercise. Conclusion： Cognitive control is extremely robust and appears not to be affected by the intensity of exercise. The selective inhibition and the between-trials adjustments are effective from the beginning to the end of exercise, regardless of the workload output.
