1. Research Center for Medical Biotechnology, Department of Biochemistry B, The Panum Institute, Blegdamsvej 3c, DK-2200 N, Copenhagen, Denmark.
2. Department of Organic Chemistry, The H. C. Ørsted Institute, Universitetsparken 5, DK-2100 Ø, Copenhagen, Denmark.
3. Polymer Group, Materials Department, Risø National Laboratory, DK-4000 Roskilde, Denmark.