•A simple solution method was used to obtain artificially covered PC-Fe2O3 semiconductor structures.•The CoWO4/Partially covered-Fe2O3-based sensor exhibited excellent ethyl acetate sensitivity ...performance.•The CoWO4/Partially covered-Fe2O3-based sensors show significant selectivity for ethyl acetate.•The discussion of the effect of ethyl acetate sensing performance caused by the formation of miniature p-n heterojunctions.
Metal organic framework (MOF)-derived porous metal oxide nanostructures have become a kind of promising material for gas-sensitive detection. A facile solvothermal method was adopted to construct CoWO4/α-Fe2O3 nanocomposites, in which MIL-53(Fe) was used as the precursor of α-Fe2O3. The prepared α-Fe2O3 has a unique three-dimensional nanostructure, resulting in good dispersion of CoWO4 nanoparticles on the surface and a distinct structure of partially CoWO4-modified α-Fe2O3 (PC-Fe2O3). XPS characterization indicates that this PC-Fe2O3 heterostructure exposes the high density of active centers, leading to an increase in the amount of adsorbed oxygen on the material surface. The sensor based on the prepared CoWO4/α-Fe2O3 composite exhibits higher response, faster response/recovery, and better selectivity to ethyl acetate than the pristine α-Fe2O3 octahedra. It is believed that the enhanced sensing performance can be attributed to the resistance modulation effect of the heterojunction, the properties of MOFs-derived material, and the formation of the unique PC-Fe2O3 structure.
•Both experiment and theoretical analysis were used to investigate flame instability.•Intrinsic flame instability in ethyl acetate premixed flame was investigated.•Evolution of flame surface crack ...and flame cellular structure were quantitatively investigated.•Influence of initial pressure and equivalence ratio on flame cellularization was investigated.
The cellular instability of ethyl acetate (EA) premixed flame has been studied theoretically and experimentally under different initial temperature, pressure and equivalence ratio. The constant pressure method (CPM) was used to determine the laminar burning velocity of EA spherical expanding flame in this research. In addition, the cellular evolution image of EA spherical expansion flame surface was obtained using high-speed schlieren technology. The image processing technology combined with three-dimensional reconstruction algorithm was used to extract and reconstruct the flame surface crack length, the number of cells on the flame surface, cellular area and cellular length scale. From the quantitative analysis of surface crack and cellular structure of EA flame, it can be seen that the evolution of flame surface crack and surface cellular structure is largely affected by equivalence ratio and initial pressure. With the increase of initial pressure or equivalence ratio, the earlier the flame surface cracks and cell formation. Furthermore, according to the cellular length scale in different radius, the wavenumber was deduced, and compared with the theoretical curve, it is found that the experimental wave numbers have the same evolution trend. Although, when the equivalence ratio is 1.4 with high Peclet number, the experimental wave numbers are somewhat beyond the boundary of the peninsula curve due to the influence of the nonlinear effects, the trend is consistent with the theoretical results.
Aryl radicals were generated for the first time from cheap and easily available aryl acyl peroxides in eco-friendly ethyl acetate under ambient conditions and visible-light illumination in the ...absence of any additive, metal catalyst, or external photosensitizer. The present arylation of quinoxalin-2(1
H
)-ones was chemo- and regioselective, and provided good access to various 3-arylquinoxalin-2(1
H
)-ones.
Aryl radicals were generated for the first time from aryl acyl peroxides in ethyl acetate under ambient conditions and visible-light illumination in the absence of any additive, metal catalyst, or external photosensitizer.
•Porous core-shell PrFeO3/α-Fe2O3 nano-octahedrons were synthesized via a facile one-step hydrothermal.•This PrFeO3/α-Fe2O3-based sensor possessed a rapid response and recovery process.•The ...PrFeO3/α-Fe2O3-based sensor exhibited low operating temperature and its response was three times to pure α-Fe2O3.•Influence on ethyl acetate sensing properties caused by the formation of p-n heterojunction was discussed.ax
Porous core-shell PrFeO3-functionalized α-Fe2O3 nano-octahedrons were synthesized via a facile one-step hydrothermal method using a metal-organic framework as self-sacrificing template. The morphology, crystalline nature, chemical compositions and specific surface area of the as-prepared PrFeO3/α-Fe2O3 nano-octahedrons were comparatively studied by a variety of techniques, including SEM, TEM, XRD, XPS and BET. The experimental results show that the PrFeO3/α-Fe2O3 composite has a novel porous core-shell octahedral structure with a large specific surface area, which indicates that the material possesses more active sites to achieve a sufficient surface chemical reaction. Herein, the gas sensing properties of the α-Fe2O3 with different PrFeO3-functionalized levels were tested, which shows that the PrFeO3/α-Fe2O3 composite realized a high gas response, low optimum operating temperature and superior selectivity to ethyl acetate gas. The response (Rair/Rgas) of the sensor based on PrFeO3/α-Fe2O3 is 22.85 toward 100 ppm ethyl acetate at 206 °C, about 3 times higher than that of pristine α-Fe2O3 sensor. Besides, the sensor possesses a rapid response and recovery speed of 8 s and 9 s for detecting 100 ppm ethyl acetate. The enhanced gas sensing properties of PrFeO3/α-Fe2O3 composite could be attributed to the unique porous core-shell morphology and p-n heterostructure between PrFeO3 and α-Fe2O3.
Sea buckthorn (Hippophae rhamnoides L.) has been designated a "medicine food homology" fruit by the National Health Commission of China due to its nutritional value. In traditional Chinese ...ethnomedicine, Hippophae rhamnoides L. is commonly used to treat nonhealing wounds such as burns, sores, and gastric ulcers. The aim of this study was to explore the healing effects of the ethyl acetate extract of sea buckthorn seeds (SBS-EF) on burn wounds.
The primary objectives of this research were to determine the most effective medicinal site of action for treating burns with sea buckthorn seeds (SBS) and to investigate the underlying material basis and mechanisms of their therapeutic effects.
The effects of different components of SBS-EF on the proliferation and migration of human skin fibroblasts (HSFs) were evaluated via MTT assays, scratch assays, transwell assays, and hydroxyproline secretion analysis. SBS-EF displayed the greatest activity amongst the extracts. Subsequent analyses included network pharmacology methodology, molecular docking studies, ultraperformance liquid chromatography UPLC-Orbitrap-Exploris-120-MS and a severe second-degree burn rat model to investigate the chemical constituents and potential therapeutic mechanisms of the SBS-EF.
In vitro studies demonstrated the efficacy of SBS-EF in promoting HSF growth and migration. UPLC-Orbitrap-Exploris-120-MS analysis revealed that SBS-EF had ten major constituents, with flavonoids being the predominant compounds, especially catechin, quercetin, and kaempferol derivatives. Network pharmacology and molecular docking analyses indicated that SBS-EF may exert its healing effects by modulating the Wnt/β-catenin signalling pathway. Subsequent in vivo experiments demonstrated that SBS-EF accelerated burn wound healing in rats, increased hydroxyproline expression in skin tissue, facilitated skin structure repair, and enhanced collagen production and organisation over a 21 d period. Additionally, exposure to SBS-EF upregulated WNT3a and β-catenin while downregulating GSK-3β levels in rat skin tissue.
The wound healing properties of SBS-EF were attributed to its ability to enhance HSF growth and migration, increase hydroxyproline levels in the skin, promote collagen accumulation, reduce scarring, and decrease the skin water content. SBS-EF may also provide therapeutic benefits for burns by modulating the Wnt/β-catenin signalling pathway, as evidenced by its effective site and likely mechanism of action in the treatment of burned rats.
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•The protective effect of the effective part of Hippophae rhamnoides L. seeds (SBS-EF) on burned.•SBS-EF treatment of burns injuries by activating Wnt/β-catenin pathway.•SBS-EF has the potential to be developed into an innovative treatment of burns product.
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