1. Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Forschungszentrum Jülich GmbH, Jülich, Germany.
2. Institute of Radiochemistry and Experimental Molecular Imaging, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.
3. Institute of Biological Information Processing, Molecular and Cell Physiology (IBI-1), Forschungszentrum Jülich GmbH, Jülich, Germany.