Characterization of event-related potentials in obsessive compulsive disorder patients: Comparison with depression and generalized anxiety disorder patients

BACKGROUND： Study results of event-refated potential in obsessive compulsive disorder （OCD） remain controversial, potentially as a result of different instruments utilized and their differing technical characteristics. OBJECTIVE： To investigate the differences in several common event-related potentials, Le. contingent negative variations, P300, and mismatch negativity （MMN）, in OCD patients, depression patients, generalized anxiety disorder （GAD） patients, and healthy controls. DESIGN, TIME AND SETTING： A case-control study was performed in the Department of Electrophysiology, Shanghai Mental Health Center from May 2002 to December 2005. PARTICIPANTS： A total of 38 OCD patients, 20 depression patients, and 18 GAD patients, who were diagnosed according to the criteria of Chinese Classification of Mental Disorders （Version 3）, formulated by the Chinese Psychiatry Association, were selected from the Outpatient Department of Shanghai Mental Health Center. Patients with two or more the above diseases were excluded. In addition, 28 healthy people, gender and age matched, were selected as controls. METHODS： Contingent negative variations, P300, and MMN were recorded by a Nicolet Spirit Instrument. All electrodes were attached at Cz according to the Intemationa11020 system, with the mastoid leads as reference and Fpz as ground. MAIN OUTCOME MEASURES： Amplitude and latency of contingent negative variations, P300, and MMN. RESULTS： The contingent negative variations, P300, and MMN were different （P 〈 0.01）. OCD patients showed an increased MI amplitude compared with controls, depression, and GAD patients （P 〈 0.01）. Target P300 amplitudes were significantly lower in OCD, depression, and GAD patients compared with controls （P 〈 0.01）. Moreover, N2 latency and latency of MMN were prolonged in OCD and depression groups compared with controls （P 〈 0.05）. CONCLUSION： Event-related potentials were different in depression, GAD, and OCD patients and healthy controls. In particular, OCD patients exhibited unique characteristics.

PtCu-SnO_(2)nanocomposites for ultrasensitive and rapid ultra-low formaldehyde sensing

SnO 2 nanospheres with diameters of 30∼50 nm and Pt x Cu 1-x bimetallic nanoparticles with sizes of approxi-mately 10 nm were synthesized via hydrothermal and solvothermal methods,respectively.The Pt x Cu 1-x bimetal-lic nanoparticles were impregnated on the surface of the SnO 2 spheres to form Pt x Cu 1-x-SnO 2 nanocomposites.By varying the atomic ratios between platinum(Pt)and copper(Cu),we found that Pt 0.75 Cu 0.25-SnO 2,with a large specific surface area of 89.21 m 2/g,enabled the selective and accurate detection of low-concentration formalde-hyde compared to other metal-deposited samples and pure SnO 2.The response value of Pt 0.75 Cu 0.25-SnO 2 to 500×10−9 formaldehyde was approximately 20 at an operating temperature of 160◦C with an extremely high-speed response(15 s).The porous structures with large specific surface areas,as well as the improved catalytic effects of Pt 0.75 Cu 0.25,comprehensively contributed to the enhanced sensing performance towards formaldehyde.