1. Biophysics SD48, NASA MSFC, Huntsville, Alabama 35812, Department of Chemical Engineering, University of Colorado at Boulder, Boulder, Colorado, 80309-0424, Stanford Synchrotron Radiation Laboratory, 2575 Sand Hill Road, MS 69, Menlo Park, California 94025, Department of Chemistry, The University of Toledo, 2801 West Bancroft Street, Toledo, Ohio 43606, and Instrumentation Technology Associates, Exton, Pennsylvania 19341