1. Department of Multifunctional Materials and Structures Laboratory, National Institute of Materials Physics, 105 Bis Atomistilor, P.O. Box MG 07, 077125 Magurele, Romania
2. Faculty of Physics, University of Bucharest, 405 Atomistilor, CP MG-1, 077125 Magurele, Romania
3. Microbiology Department, Faculty of Biology, University of Bucharest, Aleea Portocalelor 1-3, 60101 Bucharest, Romania
4. EA 4592 Géoressources & Environnement, EGID, Universite Bordeaux, 1 Allée F. Daguin 18, 33607 Pessac Cedex, France