1. Department of Respiratory Diseases, Shandong University of Traditional Chinese Medicine, Jinan, Shandong 250013, P.R. China
2. Department of Respiratory Diseases, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, Shandong 250014, P.R. China
3. Department of Respiratory Diseases, The Second Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, Shandong 250013, P.R. China