1. Department of Respiration, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710038, P.R. China
2. School of Accounting, Xijing University, Xi'an, Shaanxi 710032, P.R. China
3. Department of Medicinal Chemistry, School of Pharmacy, The Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China