Department of Pathology and Laboratory Medicine, Brown University, 70 Ship Street, Campus Box G-E5, Providence, RI 02912, USA. susan_huse@brown.edu.|Department of Pathology and Laboratory Medicine, Brown University, 70 Ship Street, Campus Box G-E5, Providence, RI 02912, USA. susan_huse@brown.edu.|Department of Computer Science, University of California, Irvine, USA. xhx@ics.uci.edu.