1 Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, Michigan.
2 Department of Pathology, University of Michigan, Ann Arbor, Michigan.
3 Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, Michigan; Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan; Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan. Electronic address: [email protected].