Notes

Extortion : The voracious prosocial technique.
Dissolution of the polyoxometalate (POM) cluster anion H5[PV2Mo10O40] (1; a mixture of positional isomers) in 50% aq H2SO4 dramatically enhances its ability to oxidize methylarenes, while fully retaining the high selectivities typical of this versatile oxidant. To better understand this impressive reactivity, we now provide new information regarding the nature of 1 (115 mM) in 50% (9.4 M) H2SO4. Data from 51V NMR spectroscopy and cyclic voltammetry reveal that as the volume of H2SO4 in water is incrementally increased to 50%, V(V) ions are stoichiometrically released from 1, generating two reactive pervanadyl, VO2+, ions, each with a one-electron reduction potential of ca. 0.95 V (versus Ag/AgCl), compared to 0.46 V for 1 in 1.0 M aq H2SO4. Phosphorus-31 NMR spectra obtained in parallel reveal the presence of PO43-, which at 50% H2SO4 accounts for all the P(V) initially present in 1. Addition of (NH4)2SO4 leads to the formation of crystalline [NH4]6[Mo2O5(SO4)4] (34% yield based on Mo), whose structure (from single-crystal X-ray diffraction) features a corner-shared, permolybdenyl [Mo2O5]2+ core, conceptually derived by acid condensation of two MoO3 moieties. While 1 in 50% aq H2SO4 oxidizes p-xylene to p-methylbenzaldehyde with conversion and selectivity both greater than 90%, reaction with VO2+ alone gives the same high conversion, but at a significantly lower selectivity. Importantly, selectivity is fully restored by adding [NH4]6[Mo2O5(SO4)4], suggesting a central role for Mo(VI) in attenuating the (generally) poor selectivity achievable using VO2+ alone. Finally, 31P and 51V NMR spectra show that intact 1 is fully restored upon dilution to 1 M H2SO4.Constructing a heterojunction and introducing an interfacial interaction by designing ideal structures have the inherent advantages of optimizing electronic structures and macroscopic mechanical properties. An exquisite hierarchical heterogeneous structure of bimetal sulfide Sb2S3@FeS2 hollow nanorods embedded into a nitrogen-doped carbon matrix is fabricated by a concise two-step solvothermal method. The FeS2 interlayer expands in situ grow on the interface of hollow Sb2S3 nanorods within the nitrogen-doped graphene matrix, forming a delicate heterostructure. Such a well-designed architecture affords rapid Na+ diffusion and improves charge transfer at the heterointerfaces. Meanwhile, the strongly synergistic coupling interaction among the interior Sb2S3, interlayer FeS2, and external nitrogen-doped carbon matrix creates a stable nanostructure, which extremely accelerates the electronic/ion transport and effectively alleviates the volume expansion upon long cyclic performance. As a result, the composite, as an anode material for sodium-ion batteries, exhibits a superior rate capability of 537.9 mAh g-1 at 10 A g-1 and excellent cyclic stability with 85.7% capacity retention after 1000 cycles at 5 A g-1. Based on the DFT calculation, the existing constructing heterojunction in this composite can not only optimize the electronic structure to enhance the conductivity but also favor the Na2S adsorption energy to accelerate the reaction kinetics. The outstanding electrochemical performance sheds light on the strategy by the rational design of hierarchical heterogeneous nanostructures for energy storage applications.A promising strategy to limit cholera severity involves blockers mimicking the canonical cholera toxin ligand (CT) ganglioside GM1. However, to date the efficacies of most of these blockers have been evaluated in noncellular systems that lack ligands other than GM1. Importantly, the CT B subunit (CTB) has a noncanonical site that binds fucosylated structures, which in contrast to GM1 are highly expressed in the human intestine. Here we evaluate the capacity of norbornene polymers displaying galactose and/or fucose to block CTB binding to immobilized protein-linked glycan structures and also to primary human and murine small intestine epithelial cells (SI ECs). We show that the binding of CTB to human SI ECs is largely dependent on the noncanonical binding site, and interference with the canonical site has a limited effect while the opposite is observed with murine SI ECs. The galactose-fucose polymer blocks binding to fucosylated glycans but not to GM1. However, the preincubation of CT with the galactose-fucose polymer only partially blocks toxic effects on cultured human enteroid cells, while preincubation with GM1 completely blocks CT-mediated secretion. Our results support a model whereby the binding of fucose to the noncanonical site places CT in close proximity to scarcely expressed galactose receptors such as GM1 to enable binding via the canonical site leading to CT internalization and intoxication. Our finding also highlights the importance of complementing CTB binding studies with functional intoxication studies when assessing the efficacy inhibitors of CT.The inability to spatiotemporally guide proteins in tissues and efficiently deliver them into cells remains a key barrier to realizing their full potential in precision medicine. learn more Here, we report ultrasound-sensitive fluoro-protein nanoemulsions which can be acoustically tracked, guided, and activated for on-demand cytosolic delivery of proteins, including antibodies, using clinically relevant diagnostic ultrasound. This advance is accessed through the discovery of a family of fluorous tags, or FTags, that transiently mask proteins to mediate their efficient dispersion into ultrasound-sensitive liquid perfluorocarbons, a phenomenon akin to dissolving an egg in liquid Teflon. We identify the biochemical basis for protein fluorous masking and confirm FTag coatings are shed during delivery, without disrupting the protein structure or function. Harnessing the ultrasound sensitivity of fluorous emulsions, real-time imaging is used to simultaneously monitor and activate FTag-protein complexes to enable controlled cytosolic antibody delivery in vitro and in vivo. These findings may advance the development of image-guided, protein-based biosensing and therapeutic modalities.Metal-air batteries have received great attention as a new energy supply for next-generation electronic devices. However, their widespread application is still hindered by several challenges including sluggish kinetics of the cathodic reactions and undesirable stability of the air cathode due to the possible deposition of the discharge product. Herein, we propose an atomic metal vacancy modulation of a single-atom dispersed Co/N/C cathode to provide the zinc-air battery with both reduced overpotential and enhanced stability. As illustrated by theoretical calculations and electrochemical measurements, deliberate introduction of metal vacancies would modulate the electronic structure and contribute to enhanced catalytic activity, affording the catalyst with a half-wave potential of 0.89 V versus reversible hydrogen electrode and an overall oxygen electrode potential gap of 0.72 V. Moreover, abundant pyridinic-N groups are exposed due to the removal of metal centers, generating strong Lewis basicity to effectively prevent the access of negatively charged zincate ions and realize the nondeposition of ZnO on the air cathode.
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