1. State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, The Chinese Academy of Sciences, Fuzhou, Fujian 350002, P. R. China, College of Chemistry & Material Science, Fujian Normal University, Fuzhou, Fujian 350007, P. R. China, and Genetics & Aging Research Unit, Massachusetts Institute of Neurodegenerative Diseases and Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129