;. Brasaemle and . Bostrom, ACKNOWLEDGMENTS: The study was supported by SOLEIL synchrotron (proposals, SOPOL) and by the Direction Générale de l'Armement (DGA 2012/93 0805, CAER). We thank C. Longin and S. Chat (Plateau de microscopie électronique MIMA2, vol.287, p.1071, 1286.