1. Department of Otolaryngology, Head & Neck Surgery, Institute of Otolaryngology, Chinese PLA General Hospital, Beijing, PR China;
2. Department of Otolaryngology, Chinese PLA General Hospital of Air Force, Beijing, PR China;
3. Department of Otolaryngology, Head & Neck Surgery, Beijing Tsinghua Changgung Hospital, Tsinghua University, Beijing, PR China;
4. Key Laboratory of Pig Industry Sciences (Ministry of Agriculture), Chongqing Academy of Animal Science, Chongqing, PR China