The exploitation of highly efficient carbon dioxide reduction (CO2RR) electrocatalyst for methane (CH4) electrosynthesis has attracted great attention for the intermittent renewable electricity ...storage but remains challenging. Here, N‐heterocyclic carbene (NHC)‐ligated copper single atom site (Cu SAS) embedded in metal–organic framework is reported (2Bn‐Cu@UiO‐67), which can achieve an outstanding Faradaic efficiency (FE) of 81 % for the CO2 reduction to CH4 at −1.5 V vs. RHE with a current density of 420 mA cm−2. The CH4 FE of our catalyst remains above 70 % within a wide potential range and achieves an unprecedented turnover frequency (TOF) of 16.3 s−1. The σ donation of NHC enriches the surface electron density of Cu SAS and promotes the preferential adsorption of CHO* intermediates. The porosity of the catalyst facilitates the diffusion of CO2 to 2Bn‐Cu, significantly increasing the availability of each catalytic center.
A catalyst with N‐heterocyclic carbene‐ligated Cu SAS as the active site, accompanied by many micro‐nano reactors, synergistically promotes the electrochemical synthesis of methane.
A metal‐free 2+2 cycloaddition and 1,4‐addition sequence induced by S‐centered radicals has been achieved by treating benzene‐linked allene‐ynes with aryldiazonium tetrafluoroborates and ...DABCO‐bis(sulfur dioxide) in a one‐pot procedure. The reaction provides a greener and more practical access to functionalized cyclobutaanaphthalen‐4‐ols with valuable applications. More than 50 examples are demonstrated with excellent diastereoselectivity and chemical yields. The reaction pathway is proposed to proceed by the following steps:2+2 cycloaddition, insertion of SO2, 1,4‐addition, diazotization, and tautomerization.
Just a DAB: A new metal‐free 2+2 cycloaddition/S‐centered radical induced 1,4‐addition sequence of benzene‐linked allene‐ynes has been established by treatment with aryldiazonium tetrafluoroborates and DABCO‐bis(sulfur dioxide) under convenient reaction conditions, thus providing practical access to functionalized cyclobutaanaphthalen‐4‐ols of chemical and biomedical importance. DABCO=1,4‐diazabicyclo2.2.2octane.
Perivascular adipose tissue (PVAT), the adipose tissue that surrounds most of the vasculature, has emerged as an active component of the blood vessel wall regulating vascular homeostasis and ...affecting the pathogenesis of atherosclerosis. Although PVAT characteristics resemble both brown and white adipose tissues, recent evidence suggests that PVAT develops from its own distinct precursors implying a closer link between PVAT and vascular system. Under physiological conditions, PVAT has potent anti-atherogenic properties mediated by its ability to secrete various biologically active factors that induce non-shivering thermogenesis and metabolize fatty acids. In contrast, under pathological conditions (mainly obesity), PVAT becomes dysfunctional, loses its thermogenic capacity and secretes pro-inflammatory adipokines that induce endothelial dysfunction and infiltration of inflammatory cells, promoting atherosclerosis development. Since PVAT plays crucial roles in regulating key steps of atherosclerosis development, it may constitute a novel therapeutic target for the prevention and treatment of atherosclerosis. Here, we review the current literature regarding the roles of PVAT in the pathogenesis of atherosclerosis.
A catalytic domino spirocyclization of 1,7-enynes with simple cycloalkanes and cyclo-1,3-dicarbonyls has been established via multiple C–C bond formations from alkynyl/alkenyl functions and dual ...α,α-C(sp3)-H abstraction/insertion. The reaction involves addition, 6-exo-dig cyclization and radical coupling sequences under convenient catalytic conditions and provides a concise access to spiro cyclopentacquinolines in good to excellent yields.
A general and efficient photocatalytic annulation‐carbohalogenation of 1,7‐enynes with a wide variety of alkyl halides was reported, which led to the atom‐economic synthesis of functionalized ...3,4‐dihydronaphthalen‐1(2H)‐ones with good yields and high stereoselectivity under the mild and oxidant‐free conditions. The reaction demonstrated remarkable compatibility regarding alkyl halides as bifunctional reagents, such as ethyl 2‐bromo‐2,2‐difluoroacetate, ethyl 2,2‐difluoro‐2‐iodoacetate, perfluorobutyl iodide, bromotrichloromethane, and diethyl 2‐bromomalonate, and enabled wide substrate scope, high functional group tolerance, and 100% atom utilization.
Soybean is grown worldwide for its high protein and oil content. Weeds compete fiercely for resources, which affects soybean yields. Because of the progressive enhancement of weed resistance to ...herbicides and the quickly increasing cost of manual weeding, mechanical weed control is becoming the preferred method of weed control. Mechanical weed control finds it difficult to remove intra-row weeds due to the lack of rapid and precise weed/soybean detection and location technology. Rhodamine B (Rh-B) is a systemic crop compound that can be absorbed by soybeans which fluoresces under a specific excitation light. The purpose of this study is to combine systemic crop compounds and computer vision technology for the identification and localization of soybeans in the field. The fluorescence distribution properties of systemic crop compounds in soybeans and their effects on plant growth were explored. The fluorescence was mainly concentrated in soybean cotyledons treated with Rh-B. After a comparison of soybean seedlings treated with nine groups of rhodamine B solutions at different concentrations ranging from 0 to 1440 ppm, the soybeans treated with 180 ppm Rh-B for 24 h received the recommended dosage, resulting in significant fluorescence that did not affect crop growth. Increasing the Rh-B solutions reduced crop biomass, while prolonged treatment times reduced seed germination. The fluorescence produced lasted for 20 days, ensuring a stable signal in the early stages of growth. Additionally, a precise inter-row soybean plant location system based on a fluorescence imaging system with a 96.7% identification accuracy, determined on 300 datasets, was proposed. This article further confirms the potential of crop signaling technology to assist machines in achieving crop identification and localization in the field.
Reactions with the unstable and highly reactive zwitterionic intermediates generated in processes catalysed by transition metals are providing new opportunities for molecular constructions. Insertion ...reactions involve the collapse of zwitterionic intermediates, but trapping them would allow structural elaborations that are not currently available. To synthesize complex molecules in this manner, reactive electrophiles can be used to trap the zwitterionic intermediates. Here, we describe the use of imines, activated by chiral organocatalysts, and a highly efficient integrated rhodium and chiral Brønsted acid co-catalysed process to trap zwitterionic intermediates that have been proposed previously to undergo a formal C-H insertion reaction, allowing us to obtain polyfunctionalized indole and oxindole derivatives in a single step with excellent diastereoselectivity and enantioselectivity.
Besides the well‐documented ophthalmic manifestations, thyroid‐associated ophthalmopathy (TAO) is believed to be related to emotional and psychological abnormalities. Given the previous neuroimaging ...evidence, we hypothesized that TAO patients would have altered neurovascular coupling associated with clinical‐psychiatric disturbances. This study was to investigate neurovascular coupling changes in TAO by combining resting‐state functional magnetic resonance imaging (rs‐fMRI) and arterial spin labeling (ASL) techniques. Amplitude of low‐frequency fluctuation (ALFF) was calculated from rs‐fMRI, and cerebral blood flow (CBF) was computed from ASL in 37 TAO patients and 21 healthy controls (HCs). Global neurovascular coupling was assessed by across‐voxel CBF‐ALFF correlation, and regional neurovascular coupling was evaluated by CBF/ALFF ratio. Auxiliary analyses were performed using fractional ALFF (fALFF) and regional homogeneity (ReHo) as rs‐fMRI measures. Compared with HCs, TAO patients showed significantly reduced global CBF‐ALFF coupling. Moreover, TAO patients exhibited decreased CBF/ALFF ratio in the left lingual gyrus (LG)/fusiform gyrus (FFG), and increased CBF/ALFF ratio in the bilateral precuneus (PCu). In TAOs, CBF/ALFF ratio in the left LG/FFG was positively correlated with visual acuity, while CBF/ALFF ratio in the bilateral PCu was negatively correlated with Montreal Cognitive Assessment score. The auxiliary analyses showed trends of reduced global neurovascular coupling (i.e., CBF‐fALFF correlation and CBF‐ReHo correlation), as well as significant altered regional neurovascular coupling (i.e., CBF/fALFF ratio and CBF/ReHo ratio) in several brain regions. These findings indicated that TAO patients had altered neurovascular coupling in the visual and higher‐order cognitive cortices. The neurovascular decoupling might be a possible neuropathological mechanism of TAO.
The monolayer transition metal dichalcogenides have recently attracted much attention owing to their potential in valleytronics, flexible and low-power electronics, and optoelectronic devices. Recent ...reports have demonstrated the growth of large-size two-dimensional MoS2 layers by the sulfurization of molybdenum oxides. However, the growth of a transition metal selenide monolayer has still been a challenge. Here we report that the introduction of hydrogen in the reaction chamber helps to activate the selenization of WO3, where large-size WSe2 monolayer flakes or thin films can be successfully grown. The top-gated field-effect transistors based on WSe2 monolayers using ionic gels as the dielectrics exhibit ambipolar characteristics, where the hole and electron mobility values are up to 90 and 7 cm2/Vs, respectively. These films can be transferred onto arbitrary substrates, which may inspire research efforts to explore their properties and applications. The resistor-loaded inverter based on a WSe2 film, with a gain of ∼13, further demonstrates its applicability for logic-circuit integrations.
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