1. Department of Pharmaceutical Sciences College of Pharmacy University of Illinois at Chicago Chicago IL 60607 USA
2. Center for Biomolecular Sciences College of Pharmacy University of Illinois at Chicago Chicago IL 60607 USA
3. Instituto de Química de São Carlos Universidade de São Paulo São Carlos SP 13560-970 Brazil
4. Departamento de Química Universidade Federal de São Carlos São Carlos SP 13565-905 Brazil