1. Biological Physics Group, Department of Physics and Astronomy, School of Natural Sciences, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
2. Rutherford Appleton Laboratory, STFC ISIS Facility, Didcot OX11 0QX, U.K.
3. Jealott’s Hill International Research Centre, Syngenta, Bracknell, Berkshire RG42 6EY, U.K.