Reproducibility of `COST Reference Microplasma Jets'

Atmospheric pressure plasmas have been ground-breaking for plasma science and technologies, due to their significant application potential in many fields, including medicinal, biological, and environmental applications. This is predominantly due to their efficient production and delivery of chemically reactive species under ambient conditions. One of the challenges in progressing the field is comparing plasma sources and results across the community and the literature. To address this a reference plasma source was established during the `Biomedical Applications of Atmospheric Pressure Plasmas' EU COST Action MP1101. It is crucial that reference sources are reproducible. Here, we present the reproducibility and variance across multiple sources through examining various characteristics, including: absolute atomic oxygen densities, absolute ozone densities, electrical characteristics, optical emission spectroscopy, temperature measurements, and bactericidal activity. The measurements demonstrate that the tested COST jets are mainly reproducible within the intrinsic uncertainty of each measurement technique

Janus model of the Na,K-ATPase beta-subunit transmembrane domain: Distinct faces mediate alpha/beta assembly and beta-beta homo-oligomerization

Na,K-ATPase is a hetero-oligomer of a and beta-subunits. The Na,K-ATPase beta-subunit (Na,K-beta) is involved in both the regulation of ion transport activity, and in cell-cell adhesion. By structure prediction and evolutionary analysis, we identified two distinct faces on the Na,K-beta transmembrane domain (TMD) that could mediate protein-protein interactions: a glycine zipper motif and a conserved heptad repeat. Here, we show that the heptad repeat face is involved in the hetero-oligomeric interaction of Na,K-beta with Na,K-alpha, and the glycine zipper face is involved in the homo-oligomerization of Na, K-beta. Point mutations in the heptad repeat motif reduced Na,K-beta binding to Na,K-a, and Na,K-ATPase activity. Na,K-beta TMD homo-oligomerized in biological membranes, and mutation of the glycine zipper motif affected oligomerization and cell-cell adhesion. These results provide a structural basis for understanding how Na,K-beta links ion transport and cell-cell adhesion. (c) 2006 Elsevier Ltd. All rights reserved.X1139sciescopu

Recovering activity of anodically challenged oxygen reduction electrocatalysts by means of reductive potential pulses

The stability of electrocatalysts is of great importance to ensure their applicability, but stability is generally only considered for catalysts polarised to a constant potential or current density. This excludes stability evaluation under start stop conditions in a fuel cell or in reversible batteries in which the catalyst is alternately polarised to high opposite potentials. For example, the poor cyclability of metal air batteries is mainly due to the decrease in the oxygen reduction activity of electrocatalysts during the high applied potentials for the oxygen evolution reaction during battery charging. To investigate and at least partially mitigate the loss of electrocatalytic activity for the oxygen reduction reaction, we employed reductive pulses with the aim of restoring the catalytic activity of the active sites for the oxygen reduction reaction. Optimisation of the reductive pulse parameters makes it possible to substantially prolong the oxygen reduction activity of a Fe Nx doped carbon based oxygen reduction electrocatalys

Catalytic Reactivation of Industrial Oxygen Depolarized Cathodes by in situ Generation of Atomic Hydrogen

Electrocatalytically active materials on the industrial as well as on the laboratory scale may suffer from chemical instability during operation, air exposure, or storage in the electrolyte. A strategy to recover the loss of electrocatalytic activity is presented. Oxygen depolarized cathodes ODC , analogous to those that are utilized in industrial brine electrolysis, are analyzed the catalytic activity of the electrodes upon storage 4 weeks under industrial process conditions 30 wt NaOH, without operation diminishes. This phenomenon occurs as a consequence of surface oxidation and pore blockage, as revealed by scanning electron microscopy, focused ion beam milling, X ray photoelectron spectroscopy, and Raman spectroscopy. Potentiodynamic cycling of the oxidized electrodes to highly reductive potentials and the formation of nascent hydrogen re reduces the electrode material, ultimately recovering the former catalytic activit

Low Overpotential Water Splitting Using Cobalt–Cobalt Phosphide Nanoparticles Supported on Nickel Foam

We report a simple, facile, and safe route for preparation of cobalt–cobalt phosphide (Co/Co2P) nanoparticles and demonstrate their application as efficient low-cost catalysts for electrochemical water splitting. The catalyst achieves good performance in catalyzing both the cathode and anode half-cell water-splitting reactions in 1.0 M KOH and the hydrogen evolution reaction in an acidic electrolyte, 0.5 M H2SO4. For the oxygen evolution reaction in 1.0 M KOH, a current of 10 mA cm–2 was attained at 0.39 V overpotential on a glassy carbon electrode, while an overpotential of 0.19 V was attained at 50 mA cm–2 when the catalyst was supported on nickel foam

Insights into the Formation, Chemical Stability, and Activity of Transient NiyP@NiOx Core-Shell Heterostructures for the Oxygen Evolution Reaction

NiyP emerged as a highly active precatalyst for the alkaline oxygen evolution reaction where structural changes play a crucial role for its catalytic performance. We probed the chemical stability of NiyP in 1 M KOH at 80 degrees C and examined how exposure up to 168 h affects its structure and catalytic performance. We observed selective P-leaching and formation of NiyP/NiOx core-shell heterostructures, where shell thickness increases with ageing time, which is detrimental for the activity. By tuning the particle size, we demonstrate that prevention of complete catalyst oxidation is essential to preserve the outstanding electrochemical performance of NiyP in alkaline media