1. Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
2. Department of Urology, Ankang Hospital of Traditional Chinese Medicine, Ankang, Shaanxi 72500, P.R. China
3. Department of Urology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710004, P.R. China