1. Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
2. The N.1 Institute for Health, National University of Singapore, 28 Medical Drive, Singapore 117456, Singapore
3. Department of Neurobiology, Peking University, Xueyuan Road 38, Beijing 100191, P.R. China
4. School of Science, Harbin Institute of Technology (Shenzhen), Taoyuan Street, Shenzhen 518055, P.R. China