1. Guangdong Geriatric Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
2. Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
3. Department of Radiology, Nanfang Hospital, Southern Medical University, Guangzhou, China
4. The Department of Developmental biology, Harvard School of Dental Medicine, Harvard Medical School, Boston, MA, USA