1. CNRS, Université de Bordeaux, ICMCB, 87 avenue du Dr. A. Schweitzer, 33608 Pessac, France, Fax: +33‐540002761
2. Departments of Chemistry and Physics, CICECO, University of Aveiro, 3810‐193 Aveiro, Portugal
3. Department of Life Sciences, Faculty of Science and Technology, and Centre of Neurosciences and Cell Biology, University of Coimbra, 3001‐401 Coimbra, Portugal