1. Department of Pharmacy; School of Pharmacy; University of Oslo; Blindern N-0316 Oslo Norway
2. Faculty of Engineering; Østfold University College; P.O. Box 700, N-1757 Halden Norway
3. Department of Electronics and Communications Engineering; Tampere University of Technology; FI-33101 Tampere Finland
4. Department of Chemistry; University of Oslo; Blindern N-0315 Oslo Norway