1. Schlumberger Cambridge Research, High Cross, Madingley Road, Cambridge CB3 0EL, United Kingdom
2. Department of Chemical Engineering, Imperial College London, London SW7 2AZ, United Kingdom
3. Computational Biophysics, Department of Science and Technology, University of Twente, Post Office Box 217, 7500 AE Enschede, The Netherlands
4. Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom