Chief Physician, Professor, and Doctoral Supervisor. Specializes in effective therapy and rehabilitation for chronic obstructive pulmonary disease (COPD) and asthma; diagnosis and treatment of difficult and rare respiratory diseases, including lymphangioleiomyomatosis (LAM), pulmonary alveolar proteinosis (PAP), cystic fibrosis (CF), tuberous sclerosis complex (TSC); diagnosis and treatment of pulmonary arterial hypertension; and chylothorax. Dr. Xu has 30 years of clinical experience. He graduated from Shanghai Medical University (now Fudan University) Medical School in 1988 and has been working at Peking Union Medical College Hospital since graduation. He obtained his Master's degree in Internal Medicine from the University of Melbourne, Australia (1995-1997), and his MD from Peking Union Medical College in 2002. From 2002 to 2005, he worked at the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health (NIH) in the USA. He has rich clinical experience in common and rare respiratory diseases, with deep research in the long-term management and rehabilitation of COPD and asthma, as well as rare diseases like LAM and PAP.