No abstract

No abstract

The repair activity of verbascoside (VER), isolated from Pedicularis spicata, towards the oxidizing hydroxyl radical adduct of dGMP and its reaction mechanism were studied using pulse radiolysis. Upon pulse radiolysis of nitrous oxide saturated aqueous solution of 2'-deoxyguanosine-5'-monophosphate (dGMP) and VER, it was found that the transient absorption spectrum of the hydroxyl adduct of dGMP decays with the formation of that of the phenoxyl radical of VER, several tens of microseconds after the electron pulse. From the formation kinetics of the phenoxyl radical of VER, the rate constant of the repair reaction was determined to be 1.12 x 10(9) dm(3) mol(-1) s(-1).

Traditional studies tend to show that the N2 potential is an index for impulse control. Some researchers doubt that the N2 potential is related to behavior suppression because the impulse control usually occurs in the behavioral inhibition condition. This study investigates whether the N2 potential is associated with the successful suppression of behavior responses in impulse control processes. We recorded event-related potentials (ERPs) while participants performed a go/no-go task (task 1) and a variation of the go/no-go task with reduced behavioral involvement during the impulse control process (task 2). In task 1, we found that, in N2, higher mean amplitude and shorter peak latency were found in the no-go condition than in the go condition. No significant difference was found for either mean amplitude or peak latency between the no-go and go conditions in task 2. Task 1 and task 2 were consistent in task procedure, ERP waveforms, ERP components, and topographical maps in the no-go condition. Results show that, in the no-go condition, the N2 potential was associated with the successful suppression of the behavior response in the impulse control process. Our results indicate that N2 is a combination of behavioral suppression and cognitive control rather than a simple ERP component that marks the cognitive impulse control process.