1. Department of Pharmacology, Shantou University Medical College, Shantou 515041, China
2. Industry & Technology Service Center, Shantou Hi-tech Industrial Development Zone, Shantou 515031, P. R. China
3. Chemistry and Chemical Engineering Guangdong Laboratory, Shantou 515031, P. R. China
4. Shantou University, Shantou 515031, P. R. China
5. Huairen City water resources Bureau, Huairen 038300, P. R. China