1. Department of Chemistry and Biochemistry; School of Science; University of Eldoret; P.O. Box 1125 Eldoret 30100 Kenya
2. Information Resources Management; School of Public Affairs; Zhejiang University; Hangzhou Zhejiang 310058 China
3. Trend Research Centre; Asia University; No. 500, Lioufeng Road Wufeng Taichung County 41354 Taiwan