1. Department of Supramolecular and Biomaterials Chemistry, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA, Leiden, The Netherlands
2. Department of Molecular Cell Biology, Section Electron Microscopy, Leiden University Medical Center, 2300 RC, Leiden, The Netherlands
3. Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MD, Eindhoven, The Netherlands
4. Department of Anatomy and Embryology, Leiden University Medical Center, Leiden University, Einthovenweg 20, 2333 ZC, Leiden, The Netherlands