1. Department of Physical Chemistry and Colloid Science, Wageningen Universiteit, Dreijenplein 6, 6703 HB Wageningen, The Netherlands, Laboratoire Environnement et Minéralurgie, UMR INPL-CNRS 7569, Centre de Recherche François Fiessinger, 15 avenue du Charmois, B.P. 40, 54501 Vandoeuvre-lès-Nancy Cedex, France, and Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan