1. Manuel Lujan Jr. Neutron Scattering Center, MS H805, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Department of Biopharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, 833 South Wood Street, Chicago, Illinois 60612, and Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439