[1] MIT, Dept Biol Engn, 77 Massachusetts Ave, Cambridge, MA 02139 USA
[2] Singapore MIT Alliance Res & Technol, Singapore, Singapore
[3] Harvard Univ, Dept Chem, 12 Oxford St, Cambridge, MA 02138 USA
[4] Integrated Lab Syst Inc, Toxicol Program, Res Triangle Pk, NC USA
[5] MIT, Dept Biol, 77 Massachusetts Ave, Cambridge, MA 02139 USA