1. Department of Physics, Technical University Berlin, D 10623 Berlin, Germany (K.K., H.K.); G. R. Harrison Spectroscopy Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (K.K., A.S.H., C.B., K.E.S.-P., J.T.M., R.R.D., M.S.F.); Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (K.K., N.Y.); and Department of Pathology, Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115 (K.B.)