1. Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
2. Division of Gastroenterology, Hepatology and Endoscopy, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA.
3. David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
4. Society of Fellows, Harvard University, Cambridge, MA 02138, USA.
5. Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.