1. Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE); University of Duisburg-Essen; Universitaetsstr. 7 45141 Essen Germany
2. Bergmannsheil University Hospital/Surgical Research; Ruhr-University of Bochum; Bürkle-de-la-Camp-Platz 1 44789 Bochum Germany
3. Institute of Physics; University of São Paulo; Rua do Matão 1371, São Paulo São Paulo 05314-970 Brazil
4. Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons; Forschungszentrum Jülich GmbH; 52425 Jülich Germany