1. Department of Physics in relation to Surgery, The Royal College of Surgeons of England, Lincoln's Inn Fields, London WC2A 3PN, U.K.
2. Department of Applied Physiology and Surgical Sciences, The Royal College of Surgeons of England, Lincoln's Inn Fields, London WC2A 3PN, U.K.
3. Department of Biochemistry, South Parks Road, Oxford OX1 3QU, U.K.