1. Medicine Experiment Center, Weifang Medical University, Wei Fang 261053, P. R. China
2. School of Bioscience and Technology, Weifang Medical University, Wei Fang 261053, P. R. China
3. Department of Biological Sciences, St. John's University, Queens, NY 11439, USA
4. Department of Pharmaceutical Sciences, St. John's University, Queens, NY 11439, USA
5. School of Basic Medical Sciences, Weifang Medical University, Wei Fang 261053, P. R. China