[1] Univ Calif Los Angeles, David Geffen Sch Med, Pasarow Mass Spectrometry Lab, Dept Psychiat & Behav Sci, Los Angeles, CA 90095 USA
[2] Univ Calif Los Angeles, David Geffen Sch Med, Semel Inst Neurosci & Human Behav, Los Angeles, CA 90095 USA
[3] Univ Calif Los Angeles, David Geffen Sch Med, Crump Inst Mol Imaging, Dept Mol & Med Pharmacol, Los Angeles, CA 90095 USA
[4] Calif State Univ Los Angeles, Dept Chem & Biochem, Los Angeles, CA 90032 USA
[5] Siemens Med Solut USA Inc, Culver City, CA 90230 USA
[6] Wuhan Univ, Sch Phys, Dept Phys, Ctr Nanosci & Nanotechnol, Wuhan 430072, Peoples R China