1. Departamento de Termodinámica Aplicada, E.T.S.I.I., Instituto de Tecnología Eléctrica, Universidad Politécnica de Valencia, Camino de Vera s/n, 46022 Valencia, Spain
2. Department of Physics, University of Ioannina, 451 10 Ioannina, Greece, and Foundation for Research and Technology-Hellas (FORTH), Biomedical Research Institute (BRI)
3. Instituto de Macromoleculas Professora Eloisa Mano, Universidade Federal do Rio de Janeiro, P.O. Box 68525, Brazil