Most antiangiogenic inhibitors targeting endothelium‐dependent vessels cannot inhibit tumor growth but promote tumor invasion and metastasis in some patients. Vasculogenic mimicry (VM) employs ...mechanisms that differ from those used to construct endothelium‐dependent vessels. Inhibiting VM may be a novel antiangiogenic strategy against alternative tumor vascularization. In this paper, myricetin was selected from among several flavonoid compounds as an effective PAR1 antagonist. In two different hepatocellular carcinoma (HCC) cell lines high‐expressed PAR1, myricetin inhibited cell migration, invasion and VM formation and reversed the expression of epithelial–endothelial transition (EET) markers by inhibiting PAR1 activation. Knockout of PAR1 inhibited HCC cell invasion and metastasis and weakened the inhibitory effect of myricetin on HCC cells. The migration, invasion and tube formation ability of PLC‐PRF‐5 cells were enhanced after PAR1 overexpression, and the inhibitory effect of myricetin was enhanced. A docking assay revealed that myricetin binds to Leu258 and Thr261 in the PAR1 activity pocket. Mutation of Leu258 and Thr261 inhibited the antitumor effect of myricetin in vitro and in vivo. In summary, myricetin reverses PAR1‐mediated EET and inhibits HCC cell invasion, metastasis, VM formation and angiogenesis by targeting PAR1, and Leu258 and Thr261 of PAR1 participate in VM and angiogenesis in HCC tissues.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Abstract One of the most important feature in the Kondo physics is the universal scaling behavior. In this study, we analyze the transport behavior of the spin thermocurrent driven by a small ...temperature bias and under a weak magnetic field. We conclude that the spin thermocurrent exhibits a universal scaling behavior, similar to the spin susceptibility. The validity of our conclusion is also checked by using the numerically exact hierarchical equations of motion approach. From our fitting result of the scaling function, it is found that the Kondo temperature can be determined by the maximum of the spin thermocurrent at T / T K = 0.383 .
Abstract
Metal-organic layers (MOLs) are highly attractive for application in catalysis, separation, sensing and biomedicine, owing to their tunable framework structure. However, it is challenging to ...obtain comprehensive information about the formation and local structures of MOLs using standard electron microscopy methods due to serious damage under electron beam irradiation. Here, we investigate the growth processes and local structures of MOLs utilizing a combination of liquid-phase transmission electron microscopy, cryogenic electron microscopy and electron ptychography. Our results show a multistep formation process, where precursor clusters first form in solution, then they are complexed with ligands to form non-crystalline solids, followed by the arrangement of the cluster-ligand complex into crystalline sheets, with additional possible growth by the addition of clusters to surface edges. Moreover, high-resolution imaging allows us to identify missing clusters, dislocations, loop and flat surface terminations and ligand connectors in the MOLs. Our observations provide insights into controllable MOL crystal morphology, defect engineering, and surface modification, thus assisting novel MOL design and synthesis.
S-aryl phosphorothioates are privileged motifs in pharmaceuticals, agrochemicals, and catalysts; yet, the challenge of devising a straightforward synthetic route to enantioenriched S-aryl ...phosphorothioates has remained unsolved to date. We demonstrate herein the first direct C-SP(=O)(OR')(OR'') coupling of diverse and chiral phosphorothioate salts with aryl iodides, enabled by an air- and moisture-stable Pd
dimer. Our mechanistic and computational data suggest distinct dinuclear Pd
catalysis to be operative, which allows for operationally simple couplings with broad scope and full retention of stereochemistry.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
A new family of 2D coordination polymers based on 3d‐4f 15‐metallacrown‐5 (MC) units were designed and characterized. The connection of the 15‐metallacrown‐5 subunits by the coordination of CuII and ...ligand led to the formation of 2D network of metallacrowns. Analysis of the magnetic properties of these coordination polymers reveals that the GdIII (1), TbIII (2), and DyIII (3) complexes exhibit slow magnetic relaxation and under 1000 Oe dc field, and the DyIII (3) complex exhibits single‐molecule magnet behavior.
A new family of 2D coordination polymers based on 3d‐4f 15‐metallacrown‐5 (MC) units was designed and characterized. The connection of the 15‐metallacrown‐5 subunits by the coordination of CuII and ligand led to the formation of 2D network of metallacrowns. The GdIII, TbIII, and DyIII complexes exhibit slow magnetic relaxation, and the DyIII complex is a single‐molecule magnet under 1000 Oe dc field.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Comprehensive Summary
Herein, we report an asymmetric two‐component alkenyl Catellani reaction for the construction of C—N axial chirality through a palladium/chiral norbornene cooperative catalysis ...and an axial‐to‐axial chirality transfer process. Various partially aromatic iodinated 2‐pyridones, quinolones, coumarin and uracil substrates react with 2,6‐disubstituted aryl bromides with a tethered amide group, to afford a wide variety of polycyclic C—N atropisomers (38 examples, up to 97% e.e.). The obtained C—N axial chirality originates from the preformed transient C—C axial chirality with high fidelity. The synthetic utility of this chemistry is demonstrated by facile preparation of complex quinoline and pyridine based C—N atropisomers through a N‐deprotection and aromatization sequence. In addition, a remote axial‐to‐central diastereoinduction process dictated by C—N axial chirality is observed with excellent diastereocontrol.
An asymmetric two‐component alkenyl Catellani reaction for the construction of C—N axial chirality is reported. This method is based on a palladium/chiral norbornene cooperative catalysis and an axial‐to‐axial chirality transfer process.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Abstract
An understanding of solid–liquid interfaces is of great importance for fundamental research as well as industrial applications. However, it has been very challenging to directly image ...solid–liquid interfaces with high resolution, thus their structure and properties are often unknown. Here, we report a quasi-liquid phase between metal (In, Sn) nanoparticle surfaces and an aqueous solution observed using liquid cell transmission electron microscopy. Our real-time high-resolution imaging reveals a thin layer of liquid-like materials at the interfaces with the frequent appearance of small In nanoclusters. Such a quasi-liquid phase serves as an intermediate for the mass transport from the metal nanoparticle to the liquid. Density functional theory-molecular dynamics simulations demonstrate that the positive charges of In ions greatly contribute to the stabilization of the quasi-liquid phase on the metal surface.
Planar chiral ferrocenes are widely studied structures in asymmetric catalysis, materials science and medicinal chemistry. Although synthetic methods for 1,2-disubstituted planar chiral ferrocenes ...are well known, methods for the direct construction of 1,3-disubstituted planar chiral ferrocenes remain elusive. Here we report a modular platform for the construction of planar chirality in 1,3-disubstituted ferrocenes/ruthenocenes via an enantioselective relay remote C-H activation strategy. This method demonstrates a mechanism for remote enantiocontrol via enantiodetermining initial C‒H activation at the C2 position, enabled by a chiral mono-N-protected natural amino-acid ligand, and subsequent relay to the remote C3 position by a bridgehead-substituted norbornene mediator. A wide variety of 1,3-disubstituted planar chiral metallocenes are prepared with high enantioselectivity (96‒99% e.e.). The reaction shows good functional-group tolerance and high step-economy, and aryl iodides/bromides are compatible as coupling partners. The resulting metallocenes can be readily derivatized to yield planar chiral ligands and catalysts for asymmetric catalysis as well as building blocks for other applications.
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GEOZS, IJS, IMTLJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK, ZAGLJ
A new ring for your indole: An unprecedented copper‐catalyzed enantioselective Friedel–Crafts alkylation/N‐hemiacetalization cascade reaction with indoles and β,γ‐unsaturated α‐ketoesters is ...reported. This mild strategy provides new access to various synthetically and biologically important 2,3‐dihydro‐1H‐pyrrolo1,2‐aindoles in a highly enantioselective manner.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Elevated concentrations of atmospheric CO2 can alter plant secondary metabolites, which play important roles in the interactions among plants, herbivorous insects and natural enemies. However, few ...studies have examined the cascading effects of host plant secondary metabolites on tri‐trophic interactions under elevated CO2 (eCO2). In this study, we determined the effects of eCO2 on the growth and foliar phenolics of Medicago truncatula and the cascading effects on two color genotypes of Acyrthosiphon pisum (pink vs. green) and their parasitoid Aphidius avenae in the field open‐top chambers. Our results showed that eCO2 increased photosynthetic rate, nodule number, yield and the total phenolic content of M. truncatula. eCO2 had contrasting effects on two genotypes of A. pisum; the green genotype demonstrated increased population abundance, fecundity, growth and feeding efficiency, while the pink genotype showed decreased fitness and these were closely associated with the foliar genstein content. Furthermore, eCO2 decreased the parasitic rate of A. avenae independent of aphid genotypes. eCO2 prolonged the emergence time and reduced the emergence rate and percentage of females when associated with the green genotype, but little difference, except for increased percentage of females, was observed in A. avenae under eCO2 when associated with the pink genotype, indicating that parasitoids can perceive and discriminate the qualities of aphid hosts. We concluded that eCO2 altered plant phenolics and thus the performance of aphids and parasitoids. Our results indicate that plant phenolics vary by different abiotic and biotic stimuli and could potentially deliver the cascading effects of eCO2 to the higher trophic levels. Our results also suggest that the green genotype is expected to perform better in future eCO2 because of decreased plant resistance after its infestation and decreased parasitic rate.
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FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
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