1. Department of Chemistry, University of Wisconsin-Stevens Point, 2100 Main Street Stevens Point, WI 54481, U.S.A.
2. Institute for Health Science Education, Queen Mary University of London, Barts and the London School of Medicine and Dentistry, Garrod Building, Turner Street, Whitechapel, London E1 2AD, U.K.
3. Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, U.K.