Stephen Kadlecek received a doctorate in physics from the University of Wisconsin in 1999. His dissertation was on the collisional processes that limit the efficiency of spin-exchange optical pumping. He remained@Wisconsin to do a year of postdoctoral work on the laser cooling and trapping of atoms before joining Amersham Health as a research physicist in 2000. Address: Amersham Health, 2500 Meridian Parkway, Durham, NC, 27713. Internet: steve.kadlecek@amersham.com