1. School of Laboratory Medicine, Chengdu Medical College, Chengdu, PR China;
2. Department of Gastroenterology, First Attached Hospital, Chengdu Medical College, Chengdu, PR China;
3. School of Pharmacy, Chengdu Medical College, Chengdu, PR China;
4. Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA;
5. Department of Chemical and Pharmaceutical Engineering, Chengdu University of Technology, Chengdu, PR China;
6. Department of Mathematics and Statistics, Wright State University, Dayton, OH, USA