1. Department of Gastroenterology, Shandong Provincial Hospital, Shandong University, Jinan, China
2. Gastroenterology center, Qingdao Hiser Hospital Affiliated to Qingdao University (Qingdao Traditional Chinese Medicine Hospital), Qingdao, China
3. Department of Gastroenterology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China.