1. Harvard−MIT Division of Health Sciences and Technology, MIT, Cambridge, Massachusetts 02139
2. Tufts University School of Medicine, Tufts Medical Center, 800 Washington Street, Boston, Massachusetts 02111
3. Department of Biology, MIT, Cambridge, Massachusetts 02139
4. Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
5. Division of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts 02115