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排序方式: 共有977条查询结果,搜索用时 15 毫秒
1.
Shanshan Zhuang Wenxiong Zheng Yunong Na Naiyi Chen Fan Gong Bingxuan Huang Stephen Brennan Charles Congyi Liu Jian Cheng Lukai Ma Huifan Liu 《International Journal of Food Science & Technology》2022,57(2):1093-1103
The β-Carotene (BC), an important precursor of vitamin A (VA), possesses antioxidant activity but is fat-soluble and has low bioavailability. In previous in-vitro assays evaluating antioxidant and 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH) free radical scavenging, both BC and VA showed a strong ability to scavenge radicals and protected cells from oxidative stress. Here, we used artificially simulated gastrointestinal digestion and Caco-2 cell absorption models to evaluate the bioavailability of the BC during gastrointestinal digestion and absorption using high-performance liquid chromatography (HPLC) analysis. We observed high absorptive and transfer rates of BC and detected retinol metabolites (Vitamin A). Therefore, BC can be detected in the acidic gastrointestinal environment using HPLC. Optimised method provided better separation of BC and VA in the column, improving the accuracy of the test results. 相似文献
2.
Qinhua Wang Xiaofeng Pan Xinpin Wang Shilin Cao Lihui Chen Xiaojuan Ma Liulian Huang Yonghao Ni 《Ceramics International》2021,47(4):4398-4403
Ti3C2Tx (MXene), a new kind of 2D ceramic nanosheets, is receiving more and more attention in the fields of medicine, biology, energy, electronics, etc. However, the preparation and application of MXene in hydrogel is still in its infancy period. Here, we review the latest progress (after 2018) related to MXene hydrogels in time. Aiming at the key issue of the dispersion stability of MXene in hydrogel systems, the preparation strategy, mechanism, advantages and disadvantages of MXene hydrogels are sorted out in detail, and the potential application prospects of MXene composite hydrogel are introduced. Finally, future viewpoints are put forward for the dispersion stability challenges that need solving in the design of MXene hydrogel. 相似文献
3.
Two‐dimensional arrangements of molecules can show remarkable cooperative electronic effects. Such effects can serve to achieve direct electronic sensing of chemical and physical processes via electrostatic effects, i.e., without transfer of charge or matter between the locus of sensing and that of detection. 相似文献
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A self-assembled monolayer (SAM) of p-hydroxymethylbenzene HOCH2C6H4 - (HOMB) moiety adsorbed on iron by the formation of a covalent bond between carbon and iron atoms was prepared by electrochemical derivatization of an iron electrode with p-hydroxymethylbenzenediazonium tetrafluoroborate HOCH2C6H4N2BF4. The electrode covered with the HOMB SAM was modified with alkyltriethoxysilanes CnH2n+1Si(OC2H5)3 (CnTES, n = 8 or 18) to prepare a film of one-dimensional polymer. The protective ability of the polymer film was determined by polarization measurement of the covered electrode in an aerated 0.5 M NaCl solution. The ability was enhanced by modification of the HOMB SAM with CnTES markedly. The iron surface coated with the one-dimensional polymer film of the HOMB SAM modified with C8TES was characterized by contact angle measurement and FTIR reflection and X-ray photoelectron spectroscopies. The persistence in the protective ability of the polymer film against iron corrosion in 0.5 M NaCl may be associated with the strong adsorption via the covalent bond, revealed by electron-probe microanalysis. 相似文献
6.
The 193 nm photochemistry of (aminoethylaminomethyl)phenethylsiloxane (PEDA) self‐assembled monolayers (SAMs) under ambient conditions is described. The primary photodegradation pathways at low exposure doses (< 100 mJ cm–2) are benzylic C–N bond cleavage (ca. 68 %), with oxidation of the benzyl C to the aldehyde, and Si–C bond cleavage (ca. 32 %). Amine‐containing photoproducts released from the SAM during exposure remain physisorbed on the surface, where they undergo secondary photolysis leading to their complete degradation and removal after ca. 1200 mJ cm–2. NaCl(aq) post‐exposure rinsing removes the physisorbed materials, showing that degradation of the original PEDA species (leaving Si–OH) is substantially complete after ca. 450 mJ cm–2. Consequently, patterned, rinsed PEDA SAMs function as efficient templates for fabrication of high‐resolution, negative‐tone, electroless metal and DNA features with good selectivity at low dose (i.e., ca. 400 mJ cm–2) via materials grafting to the intact amines remaining in the unirradiated PEDA SAM regions. 相似文献
7.
An acrylated hyperbranched poly(ester-amine) (HPEA) synthesized from piperazine and trimethylolpropanetriacrylate at a molar ratio of 1:1.42 was used as the polycation to form self-assembled films by layer-by-layer dipping with poly(sodium-p-styrenesulfonate) as the polyanion. The surface morphology and hydrophilicity of the films with HPEA as the outmost layer were controlled by adjusting the solution pH of HPEA. Due to the existence of many acrylate groups, the films with HPEA as the outmost layer were further reacted with a series of reagents, including piperazine, piperidine, laurylamine and p-phenylenediamine. The surface reactions of the films depended on both the nature of the reagents and the morphology of the initial surface. In the presence of the strong basic amines, piperazine and piperidine, the films dissolved extensively into the solution. In the case of laurylamine, a modified film with an opaque appearance was obtained due to the crystallization of long alkyl chains. With the weak basic amine p-phenylenediamine as the reactant, the film was effectively modified without any change in the surface morphology. 相似文献
8.
Upon the application of amperometric biosensor to the biological fluid, ascorbic acid interferes the amperometric determination of analytes, because the oxidative potential of ascorbic acid is lower than that of electro active substances such as H2O2 produced by the enzymatic reaction. In this study we propose a method to block ascorbic acid based on the electrostatic interaction with self-assembled monolayer (SAM) and its application of the surface modified electrode to biosensor. In order to form SAM on the gold electrode with carboxyl group, 7-carboxy-heptanethiol (7-CHT) was used. The 7-CHT modified electrode did not show anodic response to ascorbic acid, but oxidized phenanthroline cobalt complex [Co(phen)32+], which can be used as a mediator of biosensor. Thus, the 7CHT-modified electrode was applied to biosensor mediated with Co(phen)32+. Fructose dehydrogenase (FDH) was immobilized to the 7-CHT modified electrode. Fructose was determined selectively with the FDH/7-CHT modified electrode at the range of 0.2-2 mM. 相似文献
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10.
Hae Jin Kim Jin Bae Lee Young-Min Kim Myung-Hwa Jung Z. Jagličić P. Umek J. Dolinšek 《Nanoscale research letters》2007,2(2):81-86
We present synthesis, structure and magnetic properties of structurally well-ordered single-crystalline β-MnO2 nanorods of 50–100 nm diameter and several μm length. Thorough structural characterization shows that the basic β-MnO2 material is covered by a thin surface layer (∼2.5 nm) of α-Mn2O3 phase with a reduced Mn valence that adds its own magnetic signal to the total magnetization of the β-MnO2 nanorods. The relatively complicated temperature-dependent magnetism of the nanorods can be explained in terms of a superposition
of bulk magnetic properties of spatially segregated β-MnO2 and α-Mn2O3 constituent phases and the soft ferromagnetism of the thin interface layer between these two phases. 相似文献