1. Department of Respiratory Medicine, Jinling Hospital, Nanjing, Jiangsu 210002, P.R. China
2. Cadre Department of Respiratory Medicine, Jinling Hospital, Nanjing, Jiangsu 210002, P.R. China
3. Department of Orthopedics, The First Affiliated Hospital of Xi'an Medical University, Xi'an, Shaanxi 710077, P.R. China