1. Center for Research and Education in Optical Sciences and Applications, Delaware State University, Dover, DE 19901-2277, USA
2. Department of Mathematical Sciences and Department of Biological Sciences, Center for Research and Education in Optical Sciences and Applications, Applied Mathematics Research Center, Delaware State University, Dover, DE 19901-2277, USA
3. Center for Research and Education in Optical Sciences and Applications, Applied Mathematics Research Center, Department of Mathematical Sciences, Delaware State University, Dover, DE 19901-2277, USA