1. Department of Chemistry, Umeå University, Linnaeus Väg 10, 901 87 Umeå, Sweden.
2. Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen, Denmark.
3. ESRF—The European Synchrotron, 71 Avenue des Martyrs, CS40220, 38043 Grenoble, Cedex 9, France.