1. Department of Otorhinolaryngology-Head and Neck Surgery, Research Institute for Medical Science, Chungnam National University School of Medicine, Daejeon, Korea.
2. Department of Medical Science, Chungnam National University School of Medicine, Daejeon, Korea.
3. Department of Otorhinolaryngology-Head and Neck Surgery, State Key Laboratory of Respiratory Disease, The First Affiliated Hospital, Guangzhou Medical University, Guangzhou, China.