[1] Univ N Carolina, Dept Chem, Chapel Hill, NC 27599 USA
[2] Scripps Res Inst, Dept Mol & Expt Med, La Jolla, CA USA
[3] NIEHS, Reprod & Dev Toxicol Lab, Pharmacogenet Sect, Res Triangle Pk, NC 27709 USA
[4] Univ N Carolina, Chapel Hill, NC 27515 USA