1. REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal, Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, S7N 5E5, Canada, Unité Interactions et Modulateurs de Réponses, IBSM−CNRS, 31 chemin Joseph Aiguier, 13402 Marseille cedex 20, France, and Physics Department, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, 3000 Santa Fe, Argentina