1. UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology, College of Science, Engineering and Technology, University of South Africa, Muckleneuk Ridge, P.O. Box 392, Pretoria 0003, South Africa
2. Nanosciences African Network (NANOAFNET), Materials Research Department, iThemba LABS-National Research Foundation of South Africa, Old Faure Road, P.O. Box 722, Somerset West, Western Cape 7129, South Africa