Mejerschofield2754

Photoinduced decarboxylative radical reactions of benzoic acids with electron-deficient alkenes, diborane, and acetonitrile under organic photoredox catalysis conditions and mild heating afforded adducts, arylboronate esters, and the reduction product, respectively. The reaction is thought to involve single-electron transfer promoted the generation of aryl radicals via decarboxylation. A diverse range of benzoic acids were found to be suitable substrates for this photoreaction. Only our two-molecule organic photoredox system can work well for the direct photoinduced decarboxylation of benzoic acids.Engineering single-atom electrocatalysts with high-loading amount holds great promise in energy conversion and storage application. Herein, we report a facile and economical approach to achieve an unprecedented high loading of single Ir atoms, up to ∼18wt%, on the nickel oxide (NiO) matrix as the electrocatalyst for oxygen evolution reaction (OER). It exhibits an overpotential of 215 mV at 10 mA cm-2 and a remarkable OER current density in alkaline electrolyte, surpassing NiO and IrO2 by 57 times and 46 times at 1.49 V vs RHE, respectively. Systematic characterizations, including X-ray absorption spectroscopy and aberration-corrected Z-contrast imaging, demonstrate that the Ir atoms are atomically dispersed at the outermost surface of NiO and are stabilized by covalent Ir-O bonding, which induces the isolated Ir atoms to form a favorable ∼4+ oxidation state. Density functional theory calculations reveal that the substituted single Ir atom not only serves as the active site for OER but also activates the surface reactivity of NiO, which thus leads to the dramatically improved OER performance. This synthesis method of developing high-loading single-atom catalysts can be extended to other single-atom catalysts and paves the way for industrial applications of single-atom catalysts.Oxidized low-density lipoprotein (ox-LDL)- induced endothelial insults plays an important role in the pathogenesis of atherosclerosis. Donepezil is a well-known acetylcholinesterase inhibitor with its primary application being the treatment of Alzheimer's disease. More recently, there has been increased interest in donepezil as an antiatherosclerosis treatment as it possesses a host of relevant and potentially beneficial properties. In the present study, we found that donepezil could reduce the expression of lectin-type oxidized low-density lipoprotein receptor-1 (LOX-1) in human aortic endothelial cells (HAECs). We found that donepezil could suppress the expression of intercellular adhesion molecule-1 (ICAM-1), which recruits monocytes to adhere to the endothelium, by more than half. Another key finding of our study is that donepezil could reduce the expression of tumor necrosis factor receptor-α (TNF-α) and interleukin-6 (IL-6) by more than half at both the mRNA and protein transcriptional levels. Donepezil also reduced the expression of tissue factor (TF), which is considerably upregulated in atherosclerotic lesions, by more than half. Finally, we turned our attention to the early growth response protein-1 (Egr-1) for its potential role in mediating the effects of donepezil. Through our Egr-1 overexpression experiment, we found that overexpression of Egr-1 almost completely abolished the effects of donepezil described above. Thus, the effects of donepezil are likely mediated through downregulation of Egr-1. These findings provide evidence that donepezil may exert protective effects against atherosclerosis.Three classical Fe-MOFs, viz., MIL-100(Fe), MIL-101(Fe), and MIL-53(Fe), were synthesized to serve as platforms for the investigation of structure-activity relationship and catalytic mechanism in the selective conversion of H2S to sulfur. The physicochemical properties of the Fe-MOFs were characterized by various techniques. It was disclosed that the desulfurization performances of Fe-MOFs with well-defined microstructures are obviously different. Among these, MIL-100(Fe) exhibits the highest catalytic performance (ca. 100% H2S conversion and 100% S selectivity at 100-180 °C) that is superior to that of commercial Fe2O3. Furthermore, the results of systematic characterization and DFT calculation reveal that the difference in catalytic performance is mainly because of discrepancy in the amount of Lewis acid sites. A plausible catalytic mechanism has been proposed for H2S selective conversion over Fe-MOFs. This work provides critical insights that are helpful for rational design of desulfurization catalysts.Although volatile organic compound samples can be detected by gas nanosensors in adsorption principles, extreme concentrations of target gases imply the excessive adsorption, which would lead to a long recovery time and even a shortened lifetime. Herein, we report the observations of the ionization current sensing behavior on the volatile organic compounds in an ionization gas sensor with silicon-based nanostructures. The micro ionization gas sensor consists of a pair of silicon microneedle array electrodes covered by nanolayer structures and a microdischarge gas gap. The dynamic response behaviors of the sensors to the exposure of ethanol, acetone, and 2-chloroethyl ethyl sulfide have been carefully scrutinized. The sensor exhibits sound performances to the high-concentration volatile organic compounds with a fast-recovery property and could generate effective responses well at 36 V, namely, the safety operation voltages. It could be well understood by the Jesse effect where small proportion of impurities in gases could lead to an intensive increase in the overall ionization probability. Besides, the reproducibility, recovery time, sensitivity, and selectivity properties have been systematically characterized.Nitrogen mustards (NM) are an important class of chemotherapeutic drugs used in the treatment of malignant tumors. The accepted mechanism of action of nitrogen mustards (NM) is through the alkylation of DNA bases. NM-adducts block DNA replication in cancer cells by forming cytotoxic DNA interstrand cross-links. We previously characterized several adducts formed by reaction of bis(2-chloroethyl)ethylamine (NM) with calf thymus (CT) DNA and the MDA-MB-231 mammary tumor cell line. The mono-alkylated N7-guanine (NM-G) adduct, and its cross-link (G-NM-G) were major lesions. The cationic NM-G undergoes a secondary reaction through depurination to form an apurinic (AP) site or reacts with hydroxide to yield the stable ring-opened N5-substituted formamidopyrimidine (NM-Fapy-G) adduct. Both of these lesions are mutagenic and may contribute to secondary tumor development, a major clinical limitation of NM chemotherapy. VcMMAE ic50 We established a kinetic model with NM-treated female mice and measured the rates of formation and removal of NM-DNA adducts and AP sites.