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High-entropy alloy (HEA) nanoparticles are promising catalyst candidates for the acidic oxygen evolution reaction (OER). Herein, we report the synthesis of IrFeCoNiCu-HEA nanoparticles on a carbon paper substrate via a microwave-assisted shock synthesis method. Under OER conditions in 0.1 M HClO4, the HEA nanoparticles exhibit excellent activity with an overpotential of ∼302 mV measured at 10 mA cm-2 and improved stability over 12 h of operation compared to the monometallic Ir counterpart. Importantly, an active Ir-rich shell layer with nanodomain features was observed to form on the surface of IrFeCoNiCu-HEA nanoparticles immediately after undergoing electrochemical activation, mainly due to the dissolution of the constituent 3d metals. The core of the particles was able to preserve the characteristic homogeneous single-phase HEA structure without significant phase separation or elemental segregation. This work illustrates that under acidic operating conditions, the near-surface structure of HEA nanoparticles is susceptible to a certain degree of structural dynamics.

Introduction: Adoptive cellular therapy with tumor‐infiltrating lymphocytes (TIL) has demonstrated promising clinical benefits in several solid tumors, but the efficacy of this therapy might be compromised by the "prone‐to‐exhaustion" phenotype of TIL and poor persistence in vivo. This calls for a robust expansion process to produce a large number of cells for clinical usage while at the same time maintaining favorable anti‐tumor function and memory phenotype. Previous studies showed that the PI3K‐AKT signaling pathway plays a key role in the regulation of T cell activation, differentiation and memory formation. Method: We modulated the PI3K‐AKT pathway in TIL isolated from cervical and ovarian cancer by application of AKT or PI3K inhibitors or CRISPR knockout of AKT1 and/or AKT2, and characterized their effects on TIL phenotype and effector function. Mechanistic study was further performed with RNA‐seq analysis of AKT1/2 KO TIL in comparison to control TIL. Result: The inhibition of either PI3K or AKT led to an increase in the population of effector CD8+ T cells with upregulation of activation markers, elevated CD39−CD69− memory T cells, and significantly enhanced cytotoxicity when cocultured with tumor cell lines and patient‐derived tumor samples. Moreover, dual knockout of AKT1 and AKT2 largely phenocopies the functional impact of AKT or PI3K inhibition on TIL. This result was further validated by RNA‐seq analysis indicating that AKT1/2 ablation primarily regulates T cell differentiation and function‐related programs. Conclusion: Modulation of PI3K‐AKT signaling represents a promising strategy to enhance TIL stemness and cytotoxicity and improve the clinical outcome of current TIL‐based therapy to treat solid tumors. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks linked by carbon‐carbon double bonds (C=C COFs) are an emerging class of crystalline, porous, and conjugated polymeric materials with potential applications in organic electronics, photocatalysis, and energy storage. Despite the rapidly growing interest in sp2 carbon‐conjugated COFs, only a small number of closely related condensation reactions have been successfully employed for their synthesis to date. Herein, we report the first example of a C=C COF, CORN‐COF‐1 (CORN=Cornell University), prepared by N‐heterocyclic carbene (NHC) dimerization. In‐depth characterization reveals that CORN‐COF‐1 possesses a two‐dimensional layered structure and hexagonal guest‐accessible pores decorated with a high density of strongly reducing tetraazafulvalene linkages. Exposure of CORN‐COF‐1 to tetracyanoethylene (TCNE, E1/2=0.13 V and −0.87 V vs. SCE) oxidizes the COF and encapsulates the radical anion TCNE⋅− and the dianion TCNE2− as guest molecules, as confirmed by spectroscopic and magnetic analysis. Notably, the reactive TCNE⋅− radical anion, which generally dimerizes in the solid state, is uniquely stabilized within the pores of CORN‐COF‐1. Overall, our findings broaden the toolbox of reactions available for the synthesis of redox‐active C=C COFs, paving the way for the design of novel materials. [ABSTRACT FROM AUTHOR]

Encapsulating an electrocatalytic material with a semipermeable, nanoscopic oxide overlayer offers a promising approach to enhancing its stability, activity, and/or selectivity compared to an unencapsulated electrocatalyst. However, applying nanoscopic oxide encapsulation layers to high-surface-area electrodes such as nanoparticle-supported porous electrodes is a challenging task. This study demonstrates that the recently developed condensed layer deposition (CLD) method can be used for depositing nanoscopic (sub-10 nm thick) titanium dioxide (TiO 2 ) overlayers onto high-surface-area platinized carbon foam electrodes. Characterization of the overlayers by transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS) showed that the films are amorphous, while X-ray photoelectron spectroscopy confirmed that they exhibit TiO 2 stoichiometry. Electrodes were also characterized by hydrogen underpotential deposition (H upd ) and carbon monoxide (CO) stripping, demonstrating that the Pt electrocatalysts remain electrochemically active after encapsulation. Additionally, copper underpotential deposition (Cu upd ) measurements revealed that TiO 2 overlayers are effective at blocking Cu 2+ from reaching the TiO 2 /Pt buried interface and were used to estimate that between 43 and 98% of Pt surface sites were encapsulated. Overall, this study shows that CLD is a promising approach for depositing nanoscopic protective overlayers on high-surface-area electrodes.

Metal-organic frameworks (MOFs) are porous, crystalline materials constructed from organic linkers and inorganic nodes with potential utility in gas separations, drug delivery, sensing, and catalysis. Small variations in MOF synthesis conditions can lead to a range of accessible frameworks with divergent chemical or photophysical properties. New methods to controllably access phases with tailored properties would broaden the scope of MOFs that can be reliably prepared for specific applications. Herein, we demonstrate that simply increasing the reaction concentration during the solvothermal synthesis of M 2 (dobdc) (M = Mg, Mn, Ni; dobdc 4- = 2,5-dioxido-1,4-benzenedicarboxylate) MOFs unexpectedly leads to trapping of a new framework termed CORN-MOF-1 (CORN = Cornell University) instead. In-depth spectroscopic, crystallographic, and computational studies support that CORN-MOF-1 has a similar structure to M 2 (dobdc) but with partially protonated linkers and charge-balancing or coordinated formate groups in the pores. The resultant variation in linker spacings causes CORN-MOF-1 (Mg) to be strongly photoluminescent in the solid state, whereas H 4 dobdc and Mg 2 (dobdc) are weakly emissive due to excimer formation. In-depth photophysical studies suggest that CORN-MOF-1 (Mg) is the first MOF based on the H 2 dobdc 2- linker that likely does not emit via an excited state intramolecular proton transfer (ESIPT) pathway. In addition, CORN-MOF-1 variants can be converted into high-quality samples of the thermodynamic M 2 (dobdc) phases by heating in N,N -dimethylformamide (DMF). Overall, our findings support that high-concentration synthesis provides a straightforward method to identify new MOFs with properties distinct from known materials and to produce highly porous samples of MOFs, paving the way for the discovery and gram-scale synthesis of framework materials.