Oxidation of Hydroxylamine on Gold Electrodes in Aqueous Electrolytes: Rotating Ring-Disk and In Situ Infrared Reflection Absorption Spectroscopy Studies

The oxidation of hydroxylamine on Au electrodes in aqueous phosphate buffer solutions (pH 7) was examined using electrochemical and in situ infrared reflection absorption spectroscopy techniques. Polarization curves recorded with a rotating Au disk electrode showed that the onset of NH₂OH oxidation occurs at ca. 0.0 V vs SCE, reaching a well-defined peak at a disk potential, <i>E</i>_disk^peak, ca. 0.2 V vs SCE. Plots of the disk current, <i>i</i>_disk, at <i>E</i>_disk^peak vs ω^1/2 were linear with a close to zero intercept. Measurements in which <i>E</i>_disk of the rotating ring-disk electrode was scanned, while <i>E</i>_ring was fixed at a value negative enough for solution phase NO to undergo reduction, yielded plots of <i>i</i>_ring vs <i>E</i>_disk, which mirrored the peak found for <i>i</i>_disk and thus was consistent with NO being one of the predominant products of NH₂OH oxidation. In situ infrared measurements provided evidence for N₂O being produced at the same onset potential of NH₂OH oxidation. The disk polarization curves could be reproduced by theoretical simulations involving an EEECE mechanism in which nitrite, one of the products of NH₂OH oxidation, reacts with NH₂OH yielding an electrochemically inert species. In accordance with theory, plots of <i>i</i>_disk at <i>E</i>_disk^peak as a function of [NH₂OH] bent downward as [NH₂OH] increased

Evolving Applications, Technological Challenges and Future Opportunities in Neuromodulation: Proceedings of the Fifth Annual Deep Brain Stimulation Think Tank

The annual Deep Brain Stimulation (DBS) Think Tank provides a focal opportunity for a multidisciplinary ensemble of experts in the field of neuromodulation to discuss advancements and forthcoming opportunities and challenges in the field. The proceedings of the fifth Think Tank summarize progress in neuromodulation neurotechnology and techniques for the treatment of a range of neuropsychiatric conditions including Parkinson's disease, dystonia, essential tremor, Tourette syndrome, obsessive compulsive disorder, epilepsy and cognitive, and motor disorders. Each section of this overview of the meeting provides insight to the critical elements of discussion, current challenges, and identified future directions of scientific and technological development and application. The report addresses key issues in developing, and emphasizes major innovations that have occurred during the past year. Specifically, this year's meeting focused on technical developments in DBS, design considerations for DBS electrodes, improved sensors, neuronal signal processing, advancements in development and uses of responsive DBS (closed-loop systems), updates on National Institutes of Health and DARPA DBS programs of the BRAIN initiative, and neuroethical and policy issues arising in and from DBS research and applications in practice