1. College of Biomass Science and Engineering, Sichuan University, Chengdu 610065, P. R. China
2. The Key Laboratory of Leather Chemistry and Engineering of Ministry of Education, Sichuan University, Chengdu 610065, P. R. China
3. West China School of Nursing/West China Hospital, Sichuan University, Chengdu 610065, P. R. China