1,3-Butadiene formation through selective acetylene electrolysis on partially oxidized copper
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Urine electrooxidation for energy–saving hydrogen generation
Urea electrooxidation offers a cost-effective alternative to water oxidation for energy-saving hydrogen production. However, its practical application is limited by expensive urea reactants and sluggish reaction kinetics. Here, we present an efficient urine electrolysis system for hydrogen production, using cost-free urine as feedstock. Our system leverages a discovered Cl-mediated urea oxidation mechanism on Pt catalysts, where adsorbed Cl directly couple with urea to form N-chlorourea intermediates, which are then converted into N2 via intermolecular N–N coupling. This rapid mediated-oxidation process notably improves the activity and stability of urine electrolysis while avoiding Cl-induced corrosion, enabling over 200 hours of operation at reduced voltages. Accordingly, a notable reduction in the electricity consumption is achieved during urine electrolysis (4.05 kWh Nm−3) at 300 mA cm−2 in practical electrolyser for hydrogen production, outperforming the traditional urea (5.62 kWh Nm−3) and water (4.70–5.00 kWh Nm−3) electrolysis.
Astrocyte-to-neuron H2O2 signalling supports long-term memory formation in Drosophila and is impaired in an Alzheimer’s disease model
Astrocytes help protect neurons from potential damage caused by reactive oxygen species (ROS). While ROS can also exert beneficial effects, it remains unknown how neuronal ROS signalling is activated during memory formation, and whether astrocytes play a role in this process. Here we discover an astrocyte-to-neuron H2O2 signalling cascade in Drosophila that is essential for long-term memory formation. Stimulation of astrocytes by acetylcholine induces an increase in intracellular calcium ions, which triggers the generation of extracellular superoxide (O2•–) by astrocytic NADPH oxidase. Astrocyte-secreted superoxide dismutase 3 (Sod3) converts O2•– to hydrogen peroxide (H2O2), which is imported into neurons of the olfactory memory centre, the mushroom body, as revealed by in vivo H2O2 imaging. Notably, Sod3 activity requires copper ions, which are supplied by neuronal amyloid precursor protein. We also find that human amyloid-β peptide, implicated in Alzheimer’s disease, inhibits the nAChRα7 astrocytic cholinergic receptor and impairs memory formation by preventing H2O2 synthesis. These findings may have important implications for understanding the aetiology of Alzheimer’s disease.
Effect of hydrogen leakage on the life cycle climate impacts of hydrogen supply chains
Hydrogen is of interest for decarbonizing hard-to-abate sectors because it does not produce carbon dioxide when combusted. However, hydrogen has indirect warming effects. Here we conducted a life cycle assessment of electrolysis and steam methane reforming to assess their emissions while considering hydrogen’s indirect warming effects. We find that the primary factors influencing life cycle climate impacts are the production method and related feedstock emissions rather than the hydrogen leakage and indirect warming potential. A comparison between fossil fuel-based and hydrogen-based steel production and heavy-duty transportation showed a reduction in emissions of 800 to more than 1400 kg carbon dioxide equivalent per tonne of steel and 0.1 to 0.17 kg carbon dioxide equivalent per tonne-km of cargo. While any hydrogen production pathway reduces greenhouse gas emissions for steel, this is not the case for heavy-duty transportation. Therefore, we recommend a sector-specific approach in prioritizing application areas for hydrogen.
Bipolar electrochemistry-driven wireless drug loading and energy harvesting in conductive hybrid hydrogels
Bipolar electrochemistry enables wireless and spatially controlled redox reactions on (semi)conductive objects immersed in an electrolyte. Here, we investigate advanced bipolar electrochemistry applications using flexible bipolar electrodes coated with hybrid films of conductive polymer poly(3,4-ethylenedioxythiophene) and alginate hydrogels. These coatings allow for the wireless creation of reversible redox and chemical gradients, providing targeted drug loading and energy harvesting opportunities. We use cyclic voltammetry, electrochemical impedance spectroscopy, Raman microscopy, and X-ray photoelectron spectroscopy to characterize distinct redox regions within the bipolar electrode. The wireless and selective loading of a model drug, fluorescein, into the hydrogel, demonstrated control over drug distribution, suggesting an alternative to conventional uniform doping techniques. Furthermore, cutting the gradient-encoded bipolar electrode and closing an external circuit between the halves, enables energy recovery through a concentration cell mechanism. Our findings illustrate the potential of bipolar electrochemistry in creating versatile platforms that bridge materials science, electrochemistry, and bioelectronics for innovative biomedical and energy applications.
Nanomolar inhibitor of the galectin-8 N-terminal domain binds via a non-canonical cation-π interaction
Galectin-8 is a tandem-repeat galectin consisting of two distinct carbohydrate recognition domains and is a potential drug target. We have developed a library of galectin-8N inhibitors that exhibit high nanomolar Kd values as determined by a competitive fluorescence polarization assay. A detailed thermodynamic analysis of the binding of d-galactosides to galectin-8N by isothermal titration calorimetry reveals important differences in enthalpic and/or entropic contributions to binding. Contrary to expectations, the binding of 2-O-propargyl-d-galactoside was found to strongly increase the binding enthalpy, whereas the binding of 2-O-carboxymethylene-d-galactoside was surprisingly less enthalpy-driven. The results of our work suggest that the ethynyl group can successfully replace the carboxylate group when targeting the water-exposed guanidine moiety of a critical arginine residue. This results in only a minor loss of affinity and an adjusted enthalpic contribution to the overall binding due to non-canonical cation-π interactions, as evidenced by the obtained crystal structure of 2-O-propargyl-d-galactoside in complex with the N-terminal domain of galectin-8. Such an interaction has neither been identified nor discussed to date in a small-molecule ligand-protein complex.
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