1. Magnetic Resonance Center — CERM, University of Florence, Via Luigi Sacconi 6, Sesto Fiorentino, 50019 Florence, Italy
2. Department of Experimental and Clinical Biomedical Sciences ‘Mario Serio’, University of Florence, Viale Morgagni 50, 50134 Florence, Italy
3. Department of Chemistry, University of Florence, Via della Lastruccia 3, Sesto Fiorentino, 50019 Florence, Italy