1. Department of Chemical Sciences; Medical University of Plovdiv; Plovdiv Bulgaria
2. Instituto de Ingeneria, Universidad Autonoma de Baja California; Mexicali Baja California Mexico
3. Department of Biochemistry and Microbiology; Paisii Hilendarski University of Plovdiv; Plovidv Bulgaria
4. Department of Natural and Mathematical Sciences; Paisii Hilendarski University of Plovdiv; Branch Kardzhali Kardzhali Bulgaria