1 State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, P.R. China. yzhuang@simm.ac.cn.
2 College of Pharmaceutical Sciences, Zhejiang University, P.R. China. gaojianqing@zju.edu.cn and Dr Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine, Zhejiang University, P.R. China.