1. Nestec Ltd, Société des Produits Nestlé SA, P.O. Box 44, CH-1000 Lausanne 26, Switzerland
2. IBI-4, Forschungzentrum Jülich, Wilhelm Jonen Strasse, 52428 Jülich, Germany
3. Laboratory for Soft Matter and Biophysics, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium
4. Laboratory for Molecular Imaging and Photonics, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium