1. UCB, 216 Bath Road, Slough SL1 3WE, U.K.
2. Department of Biology and Biochemistry, University of Bath, Bath, U.K.
3. Department of Physics, University of Bath, Bath, U.K.
4. Department of Pharmacy and Pharmacology, University of Bath, Bath, U.K.
5. Centre for Therapeutic Innovation, University of Bath, Bath, U.K.