Carbon Dioxide-Catalyzed Stereoselective Cyanation Reaction

© 2019 American Chemical Society.We report a Michael-type cyanation reaction of coumarins by using CO2 as a catalyst. The delivery of the nucleophilic cyanide was realized by catalytic amounts of CO2, which forms cyanoformate and bicarbonate in the presence of water. Under ambient conditions, CO2-catalyzed reactions afforded high chemo- A nd diastereoselectivity of β-nitrile carbonyls, whereas only low reactivities were observed under argon or N2. Computational and experimental data suggest the catalytic role of CO2, which functions as a Lewis acid, and a protecting group to mask the reactivity of the product, suppressing byproducts and polymerization. The utility of this convenient method was demonstrated by preparing biologically relevant heterocyclic compounds with ease11sciescopu

MicroRNA expression profiling in the lungs of genetically different Ri chicken lines against the highly pathogenic avian influenza H5N1 virus

The highly pathogenic avian influenza (HPAI) virus triggers infectious diseases, resulting in pulmonary damage and high mortality in domestic poultry worldwide. This study aimed to analyze miRNA expression profiles after infection with the HPAI H5N1 virus in resistant and susceptible lines of Ri chickens.For this purpose, resistant and susceptible lines of Vietnamese Ri chicken were used based on the A/G allele of Mx and BF2 genes. These genes are responsible for innate antiviral activity and were selected to determine differentially expressed (DE) miRNAs in HPAI-infected chicken lines using small RNA sequencing. A total of 44 miRNAs were DE after 3 days of infection with the H5N1 virus. Computational program analysis indicated the candidate target genes for DE miRNAs to possess significant functions related to cytokines, chemokines, MAPK signaling pathway, ErBb signaling pathway, and Wnt signaling pathway. Several DE miRNA-mRNA matches were suggested to play crucial roles in mediating immune functions against viral evasion. These results revealed the potential regulatory roles of miRNAs in the immune response of the two Ri chicken lines against HPAI H5N1 virus infection in the lungs

The diagnostic value of circulating tumor DNA in hepatitis B virus induced hepatocellular carcinoma: a systematic review and meta-analysis

Background/Aim New biomarkers are urgently needed to aid in the diagnosis of early stage hepatocellular carcinoma (HCC). We performed a meta-analysis on the diagnostic utility of circulating tumor DNA (ctDNA) levels in patients with hepatitis B virus-induced HCC. Methods We retrieved relevant articles from PubMed, Embase, and the Cochrane Library up to February 8, 2022. Two subgroups were defined; one subset of studies analyzed the ctDNA methylation status, and the other subset combined tumor markers and ctDNA assays. Pooled sensitivity (SEN), specificity (SPE), positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and area under the summary receiver operating characteristic curve (AUC) were analyzed. Results Nine articles including 2,161 participants were included. The overall SEN and SPE were 0.705 (95% confidence interval [CI], 0.629-0.771) and 0.833 (95% CI, 0.769-0.882), respectively. The DOR, PLR, and NLR were 11.759 (95% CI, 7.982-17.322), 4.285 (95% CI, 3.098-5.925), and 0.336 (0.301-0.366), respectively. The ctDNA assay subset exhibited an AUC of 0.835. The AUC of the combined tumor marker and ctDNA assay was 0.848, with an SEN of 0.761 (95% CI, 0.659-0.839) and an SPE of 0.828 (95% CI, 0.692-0.911). Conclusions Circulating tumor DNA has promising diagnostic potential for HCC. It can serve as an auxiliary tool for HCC screening and detection, especially when combined with tumor markers

A genome-wide association study of copy-number variation identifies putative loci associated with osteoarthritis in Koreans

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.Background OA is a complex disease caused by environmental and genetic risk factors. The purpose of this study is to identify candidate copy number variations (CNVs) associated with OA. Methods We performed a genome-wide association study of CNV to identify potential loci that confer susceptibility to or protection from OA. CNV genotyping was conducted using NimbleGen HD2 3 × 720K comparative hybridization array and included samples from 371 OA patients and 467 healthy controls. The putative CNV regions identified were confirmed with a TaqMan assay. Results We identified six genomic regions associated with OA encompassing CNV loci. None of six loci had previously been reported in genome-wide association studies with OA, although a genetic analysis suggested that they have functional effects. The protein product of a candidate risk gene for obesity, TNKS, targets Wnt inhibition, and this gene was significantly associated with hand and knee OA. Copy number deletion on TNKS was associated with a 1.37-fold decreased risk for OA. In addition, CA10, which shows a strong association with osteoporosis, was also significant in our study. Copy number deletion on this gene was associated with a 1.69-fold decreased risk for OA. Conclusion We identified several CNV loci that may contribute to OA susceptibility in Koreans. Further functional investigations of these genes are warranted to fully characterize their putative association

Mesoporous Co-CoO/N-CNR nanostructures as high-performance air cathode for lithium-oxygen batteries

A bifunctional air cathode for the electrochemical oxygen reduction and evolution in a Li-O2 battery comprising Co-CoO nanoparticles embedded in the nitrogen-doped carbon nanorods (Co-CoO/N-CNR) is presented. The nanorod morphology with mesoporous nanostructures can handle continuous formation and decomposition of Li2O2 and favors the transport of electrons and ions, therefore improves the rate capability and cycle stability. Moreover, the hierarchical mesoporous Co-CoO/N-CNR reduces the overall overpotential over the cycle and decreases the side reaction between Li2O2 and carbon surface, leading to a significant enhancement of the specific capacity and cycling capability. With the cooperative effect of Co-CoO/N-CNR and porous nature, Co-CoO/N-CNR cathode delivers a high discharge specific capacity of 10,555?mAh?g?1 at 100?mA?g?1 and long cycle stability for over 86 cycles without any capacity loss at a high cutoff capacity of 1000?mAh?g?1. Furthermore, excellent performance of 7514?mAh?g?1 at 500?mA?g?1 is achieved. ? 2017 Elsevier B.V.

Pd nanoparticles deposited on Co(OH)(2)nanoplatelets as a bifunctional electrocatalyst and their application in Zn-air and Li-O(2)batteries

The development of affordable electrocatalysts for both oxygen reduction and evolution reactions (ORR/OER) has received great interest due to their importance in metal-air batteries and regenerative fuel cells. We developed a high-performance bifunctional oxygen electrocatalyst based on Pd nanoparticles supported on cobalt hydroxide nanoplatelets (Pd/Co(OH)2) as an air cathode for metal-air batteries. The Pd/Co(OH)2 shows remarkably higher electrocatalytic activity in comparison with commercial catalysts (Pt/C, IrO2), including an ORR half-wave potential (E1/2) of 0.87 V vs. RHE and an OER overpotential of 0.39 V at 10 mA cm-2 in aqueous alkaline medium. The Zn-air battery constructed with Pd/Co(OH)2 presents stable charge/discharge voltage (ΔEOER-ORR = 0.69 V), along with durable cycling stability for over 30 h. Also, this cathode exhibits a maximum discharge capacity of 17 698 mA h g-1, and stable battery operation over 50 cycles at a fixed capacity of 1000 mA h g-1, as an efficient air electrode for Li-O2 batteries, indicating that Pd/Co(OH)2 can be a potential candidate for both aqueous and non-aqueous metal-air batteries. © The Royal Society of Chemistry.1

Hierarchical Nickel–Cobalt Dichalcogenide Nanostructure as an Efficient Electrocatalyst for Oxygen Evolution Reaction and a Zn–Air Battery

A unique three-dimensional (3D) structure consisting of a hierarchical nickel–cobalt dichalcogenide spinel nanostructure is investigated for its electrocatalytic properties at benign neutral and alkaline pH and applied as an air cathode for practical zinc–air batteries. The results show a high oxygen evolution reaction catalytic activity of nickel–cobalt sulfide nanosheet arrays grown on carbon cloth (NiCo₂S₄ NS/CC) over the commercial benchmarking catalyst under both pH conditions. In particular, the NiCo₂S₄ NS/CC air cathode shows high discharge capacity, a narrow potential gap between discharge and charge, and superior cycle durability with reversibility, which exceeds that of commercial precious metal-based electrodes. The excellent performance of NiCo₂S₄ NS/CC in water electrolyzers and zinc–air batteries is mainly due to highly exposed electroactive sites with a rough surface, morphology-based advantages of nanosheet arrays, good adhesion between NiCo₂S₄ and the conducting carbon cloth, and the active layer formed of nickel–cobalt (oxy)­hydroxides during water splitting. These results suggest that NiCo₂S₄ NS/CC could be a promising candidate as an efficient electrode for high-performance water electrolyzers and rechargeable zinc–air batteries

How bulky ligands control the chemoselectivity of Pd-catalyzed: N -arylation of ammonia

This journal is © The Royal Society of Chemistry.Steric bulk has been recognized as a central design principle for supporting ligands in the widely utilized Buchwald-Hartwig amination. In a recent example, it was shown that a Pd-catalyst carrying a phosphine ligand can successfully aminate aryl halides using ammonia as the nitrogen source. Interestingly, the chemoselectivity of this reaction was found to depend on the steric demand of the phosphine ligand. Whereas a sterically less demanding phosphine affords diphenylamine as the major product, it was shown that the amination reaction can be stopped after the first amination to give aniline if a sterically more encumbering phosphine ligand is used. Density functional theory calculations were carried out to examine the relationship between the steric demand of the phosphine ligand and the chemoselectivity. It was found that the key feature that leads to the chemoselectivity is the ability of the phosphine ligand to rotate the biaryl moiety of the ligand away from the Pd-center upon amine addition to release some of the steric crowding from the Pd-coordination site11sciescopu