1. Department
of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham, DH1 3LE, U.K.
2. Ashland Inc., 1005 Route 202/206, Bridgewater, New Jersey 08807, United States
3. School
of Medicine, Pharmacy and Health, Durham University, University Boulevard, Stockton-on-Tees, TS17 6BH, U.K.