蜡样芽胞杆菌(Bacillus cereus)是一种常见的食源性致病菌。从食物中毒病人的食物残渣中分离到1株产呕吐毒素的蜡样芽胞杆菌BC307,其对青霉素类抗生素具有较强的抗性。抗SigP因子RsiP是蜡样芽胞杆菌族(Bacillus cereus sensu lato)细菌...蜡样芽胞杆菌(Bacillus cereus)是一种常见的食源性致病菌。从食物中毒病人的食物残渣中分离到1株产呕吐毒素的蜡样芽胞杆菌BC307,其对青霉素类抗生素具有较强的抗性。抗SigP因子RsiP是蜡样芽胞杆菌族(Bacillus cereus sensu lato)细菌青霉素耐药的重要调控因子。该实验利用原核系统表达RsiP蛋白并利用亲和层析法进行纯化,免疫小鼠后获得高效价多克隆抗体。结果表明,RsiP蛋白在炭疽芽胞杆菌、蜡样芽胞杆菌、苏云金芽胞杆菌中高度同源,在Western Blotting实验中RsiP抗血清与这3种菌的全菌蛋白均能发生特异性免疫反应。研究结果为探究RsiP对蜡样芽胞杆菌群细菌的青霉素耐药性调控打下了良好的基础。展开更多
The effects of the Gaussian white noise excitation on structural safety due to erosion of safe basin in Duffing oscillator with double potential wells are studied in the present paper. By employing the well-developed ...The effects of the Gaussian white noise excitation on structural safety due to erosion of safe basin in Duffing oscillator with double potential wells are studied in the present paper. By employing the well-developed stochastic Melnikov condition and Monte-Carlo method, various eroded basins are simulated in deterministic and stochastic cases of the system, and the ratio of safe initial points （RSIP） is presented in some given limited domain defined by the system＇s Hamiltonian for various parameters or first-passage times. It is shown that structural safety control becomes more difficult when the noise excitation is imposed on the system, and the fractal basin boundary may also appear when the system is excited by Gaussian white noise only. From the RSIP results in given limited domain, sudden discontinuous descents in RSIP curves may occur when the system is excited by harmonic or stochastic forces, which are different from the customary continuous ones in view of the firstpassage problems. In addition, it is interesting to find that RSIP values can even increase with increasing driving amplitude of the external harmonic excitation when the Gaussian white noise is also present in the system.展开更多
基金The project supported by the National Natural Science Foundation of China10302025The project supported by the National Natural Science Foundation of China10672140
文摘The effects of the Gaussian white noise excitation on structural safety due to erosion of safe basin in Duffing oscillator with double potential wells are studied in the present paper. By employing the well-developed stochastic Melnikov condition and Monte-Carlo method, various eroded basins are simulated in deterministic and stochastic cases of the system, and the ratio of safe initial points （RSIP） is presented in some given limited domain defined by the system＇s Hamiltonian for various parameters or first-passage times. It is shown that structural safety control becomes more difficult when the noise excitation is imposed on the system, and the fractal basin boundary may also appear when the system is excited by Gaussian white noise only. From the RSIP results in given limited domain, sudden discontinuous descents in RSIP curves may occur when the system is excited by harmonic or stochastic forces, which are different from the customary continuous ones in view of the firstpassage problems. In addition, it is interesting to find that RSIP values can even increase with increasing driving amplitude of the external harmonic excitation when the Gaussian white noise is also present in the system.
