1. School of Basic Medical Sciences North Sichuan Medical College Nanchong 637007 P. R. China
2. Henan Key Laboratory of Industrial Microbial Resources and Fermentation Technology School of Biological and Chemical Engineering Nanyang Institute of Technology Nanyang 473004 P. R. China
3. Research Institute No.280 China National Nuclear Corporation Deyang, Guanghan 618300 P. R. China
4. College of Chemistry and Life Science Chengdu Normal University Chengdu 611130 P. R. China
5. College of physics and Engineering, Chengdu Normal University Chengdu 611130 P. R. China