1. Biomedical Engineering Department, University of FloridaP.O. Box 116400, Gainesville, FL 32611, USA
2. Department of Materials Science and Engineering, University of FloridaP.O. Box 116400, Gainesville, FL 32611, USA
3. MRCAT Beamline, Advanced Photon Source, Argonne National Laboratory9700 S. Cass Avenue, Argonne, IL 60439, USA
4. Department of Geological Sciences, University of FloridaGainesville, FL 32611, USA
5. Institute for Rock Magnetism291 Shepherd Labs, 100 Union Street S.E., Minneapolis, MN 55455, USA
6. Institute for Science and Technology in Medicine, Keele UniversityThornburrow Drive, Hartshill, Stoke-on-Trent ST4 7QB, UK