Viroj Wiwanitkit1, Shunhai Qu2. 1. Hainan Medical University, Haikou, Hainan, China; Faculty of Medicine, University of Nis, Nis, Serbia; Joseph Ayobabalola University, Ikeji-Arakeji, Nigeria. 2. Journal Press of Hainan Medical College, Hainan Medical College, Haikou, Hainan, China.