以生物量和SDS-PAGE电泳表达量为判断标准进行单因素实验,结果表明:分析比较不同的大肠杆菌感受态细胞BL21(DE3)-T1R、Rosetta2(DE3)、Origami2(DE3)对于表达His-prescission蛋白的影响,确定最佳的感受态细胞为BL21(DE3)-T1R。正交实验...以生物量和SDS-PAGE电泳表达量为判断标准进行单因素实验,结果表明:分析比较不同的大肠杆菌感受态细胞BL21(DE3)-T1R、Rosetta2(DE3)、Origami2(DE3)对于表达His-prescission蛋白的影响,确定最佳的感受态细胞为BL21(DE3)-T1R。正交实验结果表明:培养基初始pH为7.0,摇床转速130 r/min,摇瓶装液量1 200 mL,接种量20 m L,培养温度37℃,OD值达到0.7时,加入IPTG 0.1 m M,诱导表达时间6 h时,蛋白表达量最大。展开更多
Using Smoluchowski equation,we study the shell effects on the emission of light particles in the fission process of a doubly magic nucleus ~(208)Pb.Calculated results show that shell has a considerable effect on the n...Using Smoluchowski equation,we study the shell effects on the emission of light particles in the fission process of a doubly magic nucleus ~(208)Pb.Calculated results show that shell has a considerable effect on the neutron emission and that shell effect gradually becomes weak with increasing excitation energy.In addition,a dependence of shell effects in the neutron emission on the angular momentum has been found.展开更多
Bifurcations of an airfoil with nonlinear pitching stiffness in incompressible flow are investigated. The pitching spring is regarded as a spring with cubic stiffness. The motion equations of the airfoil are written a...Bifurcations of an airfoil with nonlinear pitching stiffness in incompressible flow are investigated. The pitching spring is regarded as a spring with cubic stiffness. The motion equations of the airfoil are written as the four dimensional one order differential equations. Taking air speed and the linear part of pitching stiffness as the parameters, the analytic solutions of the critical boundaries of pitchfork bifurcations and Hopf bifurcations are obtained in 2 dimensional parameter plane. The stabilities of the equilibrium points and the limit cycles in different regions of 2 dimensional parameter plane are analyzed. By means of harmonic balance method, the approximate critical boundaries of 2-multiple semi-stable limit cycle bifurcations are obtained, and the bifurcation points of supercritical or subcritical Hopf bifurcation are found. Some numerical simulation results are given.展开更多
Thermodynamic hypothesis and kinetic stabil- ity are currently used to understand protein folding. The former assumes that free energy minimum is the exclusive dominant mechanism in most cases, while the latter shows ...Thermodynamic hypothesis and kinetic stabil- ity are currently used to understand protein folding. The former assumes that free energy minimum is the exclusive dominant mechanism in most cases, while the latter shows that some proteins have even lower free energy in inter- mediate states and their native states are kinetically trapped in the higher free energy region. This article explores the stability condition of protein structures on the basis of our study of complex chemical systems. We believe that sep- arating one from another is not reasonable since they should be coupled, and protein structures should be dom- inated by at least two mechanisms resulting in different characteristic states. It is concluded that： （1） Structures of proteins are dynamic, showing multiple characteristic states emerging alternately and each dominated by a respective mechanism. （2） Compromise in competition of multiple dominant mechanisms might be the key to understanding the stability of protein structures. （3） The dynamic process of protein folding should be depicted through the time series of both its energetic and structural changes, which is much meaningful and applicable than the free energy landscape.展开更多
文摘以生物量和SDS-PAGE电泳表达量为判断标准进行单因素实验,结果表明:分析比较不同的大肠杆菌感受态细胞BL21(DE3)-T1R、Rosetta2(DE3)、Origami2(DE3)对于表达His-prescission蛋白的影响,确定最佳的感受态细胞为BL21(DE3)-T1R。正交实验结果表明:培养基初始pH为7.0,摇床转速130 r/min,摇瓶装液量1 200 mL,接种量20 m L,培养温度37℃,OD值达到0.7时,加入IPTG 0.1 m M,诱导表达时间6 h时,蛋白表达量最大。
基金The project supported in part by the Foundation of Teaching & Researching of the Best Teacher of Southeast University
文摘Using Smoluchowski equation,we study the shell effects on the emission of light particles in the fission process of a doubly magic nucleus ~(208)Pb.Calculated results show that shell has a considerable effect on the neutron emission and that shell effect gradually becomes weak with increasing excitation energy.In addition,a dependence of shell effects in the neutron emission on the angular momentum has been found.
基金Project supported by the National Natural Science Foundation of China (No. 10272092) Science Foundation of Southwest Jiaotong University (No.2003B09).
文摘Bifurcations of an airfoil with nonlinear pitching stiffness in incompressible flow are investigated. The pitching spring is regarded as a spring with cubic stiffness. The motion equations of the airfoil are written as the four dimensional one order differential equations. Taking air speed and the linear part of pitching stiffness as the parameters, the analytic solutions of the critical boundaries of pitchfork bifurcations and Hopf bifurcations are obtained in 2 dimensional parameter plane. The stabilities of the equilibrium points and the limit cycles in different regions of 2 dimensional parameter plane are analyzed. By means of harmonic balance method, the approximate critical boundaries of 2-multiple semi-stable limit cycle bifurcations are obtained, and the bifurcation points of supercritical or subcritical Hopf bifurcation are found. Some numerical simulation results are given.
基金supported by the National Natural Science Foundation of China(21103195)the Knowledge Innovation Program of Chinese Academy of Sciences(KGCX2-YW-124)
文摘Thermodynamic hypothesis and kinetic stabil- ity are currently used to understand protein folding. The former assumes that free energy minimum is the exclusive dominant mechanism in most cases, while the latter shows that some proteins have even lower free energy in inter- mediate states and their native states are kinetically trapped in the higher free energy region. This article explores the stability condition of protein structures on the basis of our study of complex chemical systems. We believe that sep- arating one from another is not reasonable since they should be coupled, and protein structures should be dom- inated by at least two mechanisms resulting in different characteristic states. It is concluded that： （1） Structures of proteins are dynamic, showing multiple characteristic states emerging alternately and each dominated by a respective mechanism. （2） Compromise in competition of multiple dominant mechanisms might be the key to understanding the stability of protein structures. （3） The dynamic process of protein folding should be depicted through the time series of both its energetic and structural changes, which is much meaningful and applicable than the free energy landscape.
