1. Department of Materials Science and Engineering, Technion Israel Institute of Technology, 32000 Haifa, Israel
2. Russell Berrie Nanotechnology Institute, Technion Israel Institute of Technology, 32000 Haifa, Israel
3. European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex, France
4. X-ray Microspectroscopy and Imaging Research Group, Department of Analytical Chemistry, Ghent University, B-9000 Ghent, Belgium