1. École Normale Supérieure, Département de Chimie – Laboratoire PASTEUR, Paris, France
2. CNR-IOM, Sezione di Cagliari, Cittadella Universitaria di Monserrato, S.P.8 – km 0.700, 09042 Monserrato (CA), Italy
3. Department of Physics, University of Cagliari, Cittadella Universitaria di Monserrato, S.P.8 – km 0.700, 09042 Monserrato (CA), Italy
4. Institute for Bioengineering of Catalonia, Carrer Baldiri Reixac 10-12, 080028 Barcelona, Spain