1. Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Hebei North University, Zhangjiakou, Hebei Province, P.R. China
2. Department of Pharmacy, Hebei North University, Zhangjiakou, Hebei Province, P.R. China
3. Guangzhou Liwan Stomatological Hospital, Guangzhou, Guangdong Province, P.R. China