1. From GE Healthcare, The Grove Centre (GC18), White Lion Rd, Amersham HP7 9LL, England (A.P.L.S., P.M.E.); GE Global Research Centre, Niskayuna, NY (M.M., J.R., J.M.C., J.C., L.L., C.M.); and GE Healthcare, Life Sciences, Marlborough, Mass (M.G.H.).