1. Departmento de Bioquímica, Instituto de Química, Universidade de São Paulo, SP, Brasil P.O. Box 26077, Faculdade de Ciências Médicas de Pouso Alegre, Universidade de Pouso Alegre, Pouso Alegre, MG, Brazil, Department of Physics, Tulane University, New Orleans, Louisiana 70118, and Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08903