1. Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409-1061, United States
2. Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
3. Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas 79409, United States
4. School of Pharmaceutical Sciences and Technology, Tianjin University, Tianjin 300072, P. R. China