Unveiling the Growth Mechanism of Ordered-Phase within Multimetallic Nanoplates.

Tuning the crystal phase of alloy nanocrystals (NCs) offers an alternative way to improve their electrocatalytic performance, but, how heterometals diffuse and form ordered-phase remains unclear. Herein, for the first time, the mechanism for forming tetrametallic ordered-phase nanoplates (NPLs) is unraveled. The observations reveal that the intermetallic ordered-phase nucleates through crystallinity alteration of the seeds and then propagates by reentrant grooves. Notably, the reentrant grooves act as intermediate NCs for ordered-phase, eventually forming intermetallic PdCuIrCo NPLs. These NPLs substantially outperform for oxygen evolution reaction (221 mV at 10 mA cm-2) and hydrogen evolution reaction (19 mV at 10 mA cm-2) compared to commercial Ir/C and Pd/C catalysts in acidic media. For OER at 1.53 V versus RHE, the PdCuIrCo/C exhibits an enhanced mass activity of 9.8 A mg-1 Pd+Ir (about ten times higher) than Ir/C. For HER at -0. 2 V versus RHE, PdCuIrCo/C shows a remarkable mass activity of 1.06 A mg-1 Pd+Ir, which is three-fold relative to Pd/C. These improvements can be ascribed to the intermetallic ordered-structure with high-valence Ir sites and tensile-strain. This approach enabled the realization of a previously unobserved mechanism for ordered-phase NCs. Therefore, this strategy of making ordered-phase NPLs can be used in diverse heterogeneous catalysis.

Effect of Selective Metallic Defects on Catalytic Performance of Alloy Nanosheets.

Defects in the crystal structure of nanomaterials are important for their diverse applications. As, defects in 2D framework allow surface confinement effects, efficient molecular accessibility, high surface-area to volume-ratio and lead to higher catalytic activity, but it is challenging to expose defects of specific metal on the surface of 2D alloy and find the correlation between defective structure and electrocatalytic properties with atomic precision. Herein, the work paves the way for the controlled synthesis of ultrathin porous Ir-Cu nanosheets (NSs) with selectively iridium (Ir) rich defects to boost their performance for acidic oxygen evolution reaction (OER). X-ray absorption spectroscopy reveals that the oxidized states of Ir in defects of porous NSs significantly impact the electronic structure and decline the energy barrier. As a result, porous Ir-Cu/C NSs deliver improved OER activity with an overpotential of 237 mV for reaching 10 mA cm-2 and exhibit significantly higher mass activity than benchmark Ir/C under acidic conditions. Therefore, the present work highlights the concept of constructing a selective noble metal defect-rich open structure for catalytic applications.

Circular RNA circ_0029589 promotes ox-LDL-induced endothelial cell injury through regulating RAB22A by serving as a sponge of miR-1197.

BACKGROUND: Dysfunction of endothelial cells is now considered a vital contributor to the pathogenesis of atherosclerosis (AS). Moreover, circular RNA (circRNA) circ_0029589 has been found to be involved in the regulation of oxidized low-density lipoprotein (ox-LDL)-induced endothelial cell damage. Nevertheless, its molecular mechanism in ox-LDL-triggered endothelial cell injury is poorly defined. METHODS: Human umbilical vein endothelial cells (HUVECs) treated with ox-LDL were applied as cell models of AS. Circ_0029589, microRNA-1197 (miR-1197), and Ras-related protein Rab-22A (RAB22A) expression were detected using real-time quantitative polymerase chain reaction (RT-qPCR). Cell proliferation, apoptosis, angiogenesis, and invasion were detected using 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT), 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, tube formation, and transwell assays. Western blot analysis of Cleaved-caspase-3, B-cell lymphoma-2 related X protein (Bax), and RAB22A. IL-6, IL-1ß, and Tumor necrosis factor α (TNF-α) levels were gauged using ELISA kits. Superoxide Dismutase (SOD) activity and Malondiahyde (MDA) level were assessed using special kits. Bioinformatics software predicted the binding between miR-1197 and circ_0029589 or RAB22A, which was proved using dual-luciferase reporter and RNA pull-down assays. RESULTS: Circ_0029589 and RAB22A expression were strengthened, and miR-1197 was reduced in ox-LDL-treated HUVECs. Importantly, circ_0029589 silencing ameliorated ox-LDL-triggered HUVEC damage via promoting cell proliferation, tube formation ability, invasion, and repressing cell apoptosis, inflammation, and oxidative stress. Mechanical analysis suggested that circ_0029589 might affect RAB22A content through sponging miR-1197. CONCLUSION: Circ_0090231 might protect against ox-LDL-mediated HUVEC injury via the miR-1197/RAB22A axis, which provides a therapeutic strategy for endothelial cell damage of AS.

Unprecedented Dual Role of Polyaniline for Enhanced Pseudocapacitance of Cobalt-Iron Layered Double Hydroxide.

Creating nanosized pores in layered materials can increase the abundant active surface area and boost potential applications of energy storage devices. Herein, a unique synthetic strategy based on polyaniline (PANI) doped 2D cobalt-iron layered double hydroxide (CoFe-LDH/P) nanomaterials are designed, and the formation of pores at low temperature (80 °C) is developed. It is found that the optimized concentration of PANI creates the nanopores on the CoFe-LDH nanosheets among all other polymers. The well-ordered pores of CoFe-LDH/P allow the high accessibility of the redox-active sites and promote effective ion diffusion. The optimized CoFe-LDH/P2 cathode reveals a specific capacitance 1686 (1096 Cg-1 ) and 1200 Fg-1 (720 Cg-1 ) at 1 and 30 Ag-1 respectively, a high rate capability (71.2%), and a long cycle life (98% over 10 000 cycles) for supercapacitor applications. Charge storage analysis suggests that the CoFe-LDH/P2 electrode displays a capacitive-type storage mechanism (69% capacitive at 1 mV s-1 ). Moreover, an asymmetric aqueous supercapacitor (CoFe-LDH/P2//AC) is fabricated, delivering excellent energy density (75.9 Wh kg-1 at 1124 W kg-1 ) with outstanding stability (97.5%) over 10 000 cycles. This work opens a new avenue for designing porous 2D materials at low temperature for aqueous energy storage devices.

Solid-Contact Potentiometric Anion Sensing Based on Classic Silver/Silver Insoluble Salts Electrodes without Ion-Selective Membrane.

Current solid potentiometric ion sensors mostly rely on polymeric-membrane-based, solid-contact, ion-selective electrodes (SC-ISEs). However, anion sensing has been a challenge with respect to cations due to the rareness of anion ionophores. Classic metal/metal insoluble salt electrodes (such as Ag/AgCl) without an ion-selective membrane (ISM) offer an alternative. In this work, we first compared the two types of SC-ISEs of Cl- with/without the ISM. It is found that the ISM-free Ag/AgCl electrode discloses a comparable selectivity regarding organic chloride ionophores. Additionally, the electrode exhibits better comprehensive performances (stability, reproducibility, and anti-interference ability) than the ISM-based SC-ISE. In addition to Cl-, other Ag/AgX electrodes also work toward single and multi-valent anions sensing. Finally, a flexible Cl- sensor was fabricated for on-body monitoring the concentration of sweat Cl- to illustrate a proof-of-concept application in wearable anion sensors. This work re-emphasizes the ISM-free SC-ISEs for solid anion sensing.

Tranilast inhibits angiotensin II-induced myocardial fibrosis through S100A11/ transforming growth factor-ß (TGF-ß1)/Smad axis.

Tranilast has an ameliorative effect on myocardial fibrosis (MF), but the specific mechanism has not been studied. S100A11 is a key regulator of collagen expression in MF. In this paper, we will study the regulatory roles of Tranilast and S100A11 in MF. After the introduction of angiotensin II (AngII) to Human cardiac fibroblasts (HCF), Tranilast was administered. CCK-8 kit was used to detect cell viability. Wound Healing assay detected cell migration, and Western blot was used to detect the expression of migration-related proteins and proteins related to extracellular matrix synthesis. The expression of α-SMA was detected by immunofluorescence (IF). The expression of S100A11 was detected by qPCR and Western blot, and then S100A11 was overexpressed by cell transfection technology, so as to explore the mechanism by which Tranilast regulated MF. In addition, the expression of TGF-ß1/Smad pathway related proteins was detected by Western blot. Tranilast inhibited Ang II-induced over-proliferation, migration and fibrosis of human cardiac fibroblasts (HCF), and simultaneously significantly decreased S100A11 expression was observed. Overexpression of S100A11 reversed the inhibition of Tranilast on AngII-induced over-proliferation, migration, and fibrosis in HCF, accompanied by activation of the TGF-ß1/Smad pathway. Overall, Tranilast inhibits angiotensin II-induced myocardial fibrosis through S100A11/TGF-ß1/Smad axis.