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关键词： Buchwald catalysts   C-N coupling reaction   Catalyst deactivation   Density functional theory   Kinetic study   Palladium  

摘要： The kinetics of N-arylation of morpholine with 1-chloro-4-fluorobenzene in presence of Buchwald precatalysts of the third (G3), fourth (G4) and fifth (G5) generations with RuPhos (2-dicyclohexylphosphino-2′,6′-diisopropoxybiphenyl) was studied by ¹⁹F NMR spectroscopy. Effective rate constants for CN coupling reaction were determined. Experimental results were supported by DFT calculations of the precatalyst activation pathway leading to Pd⁰(RuPhos), as well as calculations of the energy profiles of reductive elimination stage of N-arylation reaction. It was found that the efficiency of these precatalysts enhanced in the G3 < < G5 < G4 series. Considerably lower activity of G3 precatalyst is caused by palladium centers blocking due to reaction with carbazole, which evolves upon elimination of 2-aminobiphenyl and then leads to formation of kinetically and thermodynamically stable Pd(RuPhos)(aryl)(carbazolyl) complex. Catalyst deactivation by carbazole was confirmed by separate experiment as well as by DFT calculations. The superior performance of G4 precatalyst stems from the lowest free energy barrier for the rate-limiting stage of the activation pathway (reductive elimination of carbazole) and the largest negative value of overall free energy change in it. Single crystal X-ray structure of Pd G4 RuPhos precatalyst was determined.

关键词： Highland red rice resistant starch   Antidiabetic   Gut microbiota-PYY/GLP-1 pathway  

摘要： Highland red rice from southwestern China is recognized as a health-promoting grain,but its potential in dia-betes management remains underexplored.In this study,resistant starch(RS)and pigment extracts(RP)were isolated from highland red rice to determine whether they act in combination to modulate gut microbiota and metabolism in streptozotocin(STZ)-induced diabetic mice,with the aim of elucidating the mechanisms under-lying their anti-hyperglycemic effects.Neither RS nor RP single interventions significantly improved key gly-cemic parameters;however,the combined intervention(RSP)significantly reduced fasting blood glucose(FBG)levels and improved glucose tolerance.16S rRNA analysis indicated RSP intervention increased the abundance of short-chain fatty acid(SCFA)-producing bacteria,including Lactobacillus,Lactococcus,Akkermansia,and Rom-boutsia,while decreasing pro-inflammatory taxa such as Candidatus_Arthromitus.Metabolomic analysis revealed RSP intervention elevated levels of cholic acid(CA),hyocholic acid(HCA),and sphingolipid metabolism in-termediates(sphingosine and sphinganine).Crucially,both SCFA concentrations and the expression of peptide YY(PYY)and glucagon-like peptide-1(GLP-1)were significantly elevated after RSP intervention.These findings demonstrate that RS and RP together exert combined anti-hyperglycemic effects by modulating gut microbiota and its metabolites,thereby activating the PYY/GLP-1 signaling.This highlights the therapeutic potential of highland red rice components in diabetes management.

关键词： Redox   EEF   Conformational switching   1,1′-Bianthracene  

摘要：

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  Redox-driven single-electron transfer enables free anthracene ring rotation, yielding bistability in 1,1’-bianthracene.
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  NPA and spin density reveal excess electrons localizing on the axis in cationic (1^-) and anionic (1⁺) radicals, driving conformational shifts.
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  Nonlinear optical (NLO) response is highly redox-sensitive; β_tot rises sharply upon electron gain or loss. UV-Vis spectra show redshift and new 500-700 nm peaks, corroborating enhanced β_tot.
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  An oriented external electric field modulates electron aggregation sites, altering relative energies of acute and obtuse configurations to induce transitions.

关键词： Carlin-type goldore   Pyrite   Calcite   Depressant   2-Phosphonobutane-1,2,4-tricarboxylic acid   Chelation  

摘要：

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  PBTCA can significantly improve the gold grade and recovery in the flotation of Carlin-type gold ore.
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  PBTCA exerts highly selective depression on calcite under acidic conditions.
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  PBTCA significantly reduces the adverse effect of Ca²⁺ dissolved from calcite and other calcium-bearing minerals on pyrite flotation.
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  PBTCA is chemically adsorbed on the calcite surface via chelation with Ca²⁺, forming hydrophilic Ca–O–P bonds and hydrogen bonds.
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  PBTCA provides an efficient and eco-friendly calcium-bearing mineral depressant for the flotation separation of pyrite and calcite.

关键词： Angiogenesis   Collagen–chitosan scaffold   Deferoxamine   Diabetic wound healing   HIF-1α stabilization   Oxidative stress   Tissue regeneration  

摘要： Diabetic wounds are characterized by impaired angiogenesis, prolonged inflammation, and delayed tissue regeneration, which often result in chronic non-healing ulcers. Hypoxia-inducible factor-1 alpha (HIF-1α) signaling plays a critical role in coordinating angiogenesis and tissue repair; however, its activity is markedly suppressed in diabetic conditions. This study aimed to evaluate the therapeutic efficacy of a collagen–chitosan sponge scaffold (CoChSS) loaded with deferoxamine (DFO) in enhancing diabetic wound healing through modulation of the hypoxic microenvironment and activation of angiogenic pathways. Type 2 diabetic rats were randomly assigned to three groups: untreated control, CoChSS scaffold alone, and DFO-loaded CoChSS (CoChSS/DFO). Full-thickness excisional wounds were created, and healing outcomes were evaluated on days 4 and 8 post-injury. Wound closure rate, mechanical properties, stereological parameters (fibroblast density, blood vessel density, and inflammatory cell infiltration), collagen deposition, gene expression (HIF-1α and SDF-1α, VEGF, TGF-β, TNF-α, IL-1β), and oxidative stress markers (CAT, SOD, GSH, and MDA) were systematically assessed. The CoChSS/DFO group exhibited significantly accelerated wound closure compared with both control and scaffold-only groups (P < 0.05). Mechanical testing demonstrated enhanced tensile strength and energy absorption in regenerated tissue following CoChSS/DFO treatment (P < 0.05). Stereological analysis revealed markedly increased angiogenesis and fibroblast proliferation, accompanied by a significant reduction in inflammatory cell infiltration (P < 0.05). Histological evaluation using Masson’s trichrome staining showed enhanced collagen deposition and improved matrix organization in the CoChSS/DFO group (P < 0.05). At the molecular level, CoChSS/DFO significantly upregulated HIF-1α, SDF-1α, VEGF, and TGF-β expression, while suppressing pro-inflammatory cytokines TNF-α and IL-1β (P < 0.05).

关键词： 1,2-Naphthoquinone 1-methides   1H-benzo[f]chromenes   Betti bases   Push-pull 1,3-butadienes   [4 + 2]-cycloaddition  

摘要： An efficient synthesis of the 1H-benzo[f]chromenes containing dicyanovinylidene, cyanoacrylate or cyanoacetamide moieties at C2-position starting from β-naphthol Mannich bases is described. The cascade process starts with the thermolytic generation of 1,2-naphthoquinone 1-methides, their further oxa-Diels-Alder reaction with push-pull butadienes followed by elimination of the secondary amine. The obtained 1H-benzo[f]chromenes were successfully used for the synthesis of benzylated N-heterocycles by addition of N-nucleophile, heterocyclization and dihydropyran ring opening sequence.

关键词： Cyclooxygenase (COX-1)   Mofezolac   Ovarian Cancer   Machine Learning   Molecular docking   Molecular dynamic simulation  

摘要： Cyclooxygenase-1 (COX-1, PTGS1) has recently re-emerged as a significant therapeutic target in inflammatory diseases and ovarian cancer, particularly due to its high expression in high-grade serous ovarian carcinoma. Elucidating the structural determinants that govern the selective binding of inhibitors within the COX-1 catalytic pocket is essential for rational drug design. In this study, we investigated the binding behavior and potential cross-target activity of the selective COX-1 inhibitor mofezolac using an integrated artificial intelligence–assisted pocket-based drug discovery framework. Dynamic protein binding site’s volumetric topology based binding pocket similarity analysis was performed to identify proteins possessing similar binding cavities structurally comparable to the COX-1-mofezolac complex (5WBE). Five structurally related proteins were identified based on conserved dynamic pocket geometry and physicochemical descriptors. Molecular docking and 200 ns MD simulations were subsequently executed to evaluate the stability, interaction dynamics, and binding mechanisms of mofezolac within these COX-1-like pockets. Binding free-energy calculations using the MM/GBSA approach revealed favorable and thermodynamically stable interactions across all systems, with ΔG_bind values ranging from –24.16 to –54.18 kcal/mol. Molecular dynamics analysis further identified conserved phenylalanine residues acting as dynamic hydrophobic gatekeepers, stabilizing mofezolac through persistent aromatic interactions. Computational mutagenesis (Phe→Ala) supported the contribution of these residues to ligand stabilization, as mutation reduced the predicted binding strength. These conserved hydrophobic pocket architectures can facilitate cross-target ligand recognition and highlight the importance of aromatic gatekeeper residues in stabilizing COX-1 inhibitors. Importantly, these findings suggest that mofezolac may engage structurally conserved binding environments across multiple

关键词： 35L67   35Q30   76L05   Compressible Navier-Stokes equations   Contact wave   Optimal decay rate   Nonlinear stability  

摘要： This paper investigates the decay rates of the contact wave in one-dimensional Navier-Stokes equations. We study two cases of perturbations, with and without zero mass condition, i.e., the integration of initial perturbations is zero and non-zero, respectively. For the case without zero mass condition, we obtain the optimal decay rate ${(1+t)}^{-\frac{1}{2}}$ for the perturbation in $L^{\infty }$ norm. We applied the anti-derivative method, introducing the diffusion wave to carry the initial excess mass, diagonalizing the integrated system, and estimating the energy of perturbation in the diagonalized system. Precisely, due to the presence of diffusion waves, the decay rates for errors of the perturbed system are too poor to get the optimal decay rate. We find the dissipation structure in the diagonalized system, see (3.16). This observation makes us able to fully utilize the fact that the sign of the derivative of the contact wave is invariant and to control the terms with poor decay rates in energy estimates. For the case with zero mass condition, there are also terms with poor decay rates. In this case, note that there is a cancellation in the linearly degenerate

摘要：

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  4-(Isopropyl)-β-methylcyclohexanethanol; a safety assessment based on RIFM's criteria.
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  A safety assessment based on 7 human health endpoints plus environmental.
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  All endpoints were cleared using target data, read-across, and/or TTC.

关键词： Near-infrared   Organic light-emitting diodes   Hybrid local and charge transfer   Aggregated-induced emission   Benzothiadiazole derivatives  

摘要：

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  A fused acceptor, acenaphtho [1,2-b][1,2,5]thiadiazolo [3,4-g]quinoxaline (APTQ), is developed for NIR emitter design.
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  The twisted D-A-D fluorophore exhibits HLCT characteristics with AIE behavior.
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  Efficient NIR electroluminescence is achieved with an emission peak at 760 nm and high spectral purity (>95% beyond 700 nm).
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  A maximum EQE of 2.71% is obtained, representing competitive performance for HLCT-based NIR OLEDs.