1. Laser Biomedical Research Center, G. R. Harrison Spectroscopy Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts
02139, United States
2. College
of Medicine, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
3. Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, New
York 10065, United States