1. Institute for Physical Chemistry, Friedrich-Alexander-Universität, Erlangen-Nürnberg, 91058 Erlangen, Germany, Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, Department of Chemical Engineering and Departments of Materials Science and Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109, and Dipartimento di Scienze Farmaceutiche, Università di Trieste, Piazzale Europa 1, 34127 Trieste, Italy