1. Koch Institute for Integrative Cancer Research Massachusetts Institute of Technology Cambridge MA 02139 USA
2. Division of Gastroenterology Brigham and Women's Hospital Harvard Medical School Boston MA 02115 USA
3. Division of Gastroenterology Massachusetts General Hospital Harvard Medical School Boston MA 02115 USA
4. Division of Comparative Medicine Massachusetts Institute of Technology Cambridge MA 02139 USA
5. Division of Pulmonary and Critical Care Medicine Department of Medicine Brigham and Women's Hospital, Harvard Medical School Boston MA 02115 USA
6. Department of Mechanical Engineering Massachusetts Institute of Technology Cambridge MA 02139 USA