1. Department of Chemistry, The Chinese University of Hong Kong, Shatin, N. T., Hong Kong, China
2. School of Life Sciences, The Chinese University of Hong Kong, Shatin, N. T., Hong Kong, China
3. Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
4. Department of Biomedical Sciences, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China