1. State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Cheng Du, China
2. Departments of Pharmacology and Toxicology, and Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS, USA
3. Nuclear Magnetic Resonance Laboratory, Molecular Structures group, School of Pharmacy, University of Kansas, Lawrence, KS, USA