1. Department of Chemistry, Bedson Building, University of Newcastle upon Tyne, Newcastle upon Tyne, NE1 7RU, U.K., Department of Chemistry, Dainton Building, Brook Hill, University of Sheffield, Sheffield, S3 7HF, U.K., Department of Clinical Biochemistry, The Medical School, University of Newcastle upon Tyne, Newcastle upon Tyne, NE2 4HH, U.K., Cambridge Life Sciences plc, Cambridgeshire Business Park, Angel Drove, Ely, Cambridgeshire CB7 4DT, U.K.