1. Department of Gastroenterology and Hepatology; The First Affiliated Hospital; Sun Yat-sen University; Guangzhou China
2. Department of Medicine; The Feinberg School of Medicine; Northwestern University; Chicago IL USA
3. Department of Gastroenterology; Barts and the London School of Medicine and Dentistry; Wingate Institute of Neurogastroenterology; Queen Mary University of London; London UK