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101.
Álvaro Santana-Mayor Ruth Rodríguez-Ramos Bárbara Socas-Rodríguez Miguel Ángel Rodríguez-Delgado Giovanni D'Orazio 《Electrophoresis》2020,41(20):1768-1775
The separation of 11 phthalic acid ester (PAEs) was carried out by nano-liquid chromatography coupled to ultraviolet and MS detection. Preliminary experiments were achieved in order to select suitable stationary phases and chromatographic conditions. The baseline separation was obtained, for all compounds, with an XBridgeTM C18 column in less than 15 min, working in step gradient mode. The sensitivity of the method was improved by on-column focusing. PAEs were extracted from alcoholic and nonalcoholic beverages using vortex-assisted emulsification dispersive liquid–liquid microextration and natural deep eutectic solvents. The whole method was validated in terms of linearity, sensitivity, precision, recovery, and repeatability. Combination of both off-line sample preparation preconcentration and large injection volume led to obtain LOQs in the range 5–47 ng/mL. The developed nano-LC-UV method was extended to MS detection to confirm the presence of PAEs in some beverages commercialized in different types of packaging. 相似文献
102.
Journal of Applied and Industrial Mathematics - We study the problem of optimal location of the ambulance fleet at the base stations. The objective is to minimize the average waiting time for... 相似文献
103.
Chebodaeva V. V. Sedelnikova M. B. Bakina O. V. Sharkeev Yu. P. 《Russian Physics Journal》2021,64(8):1435-1442
Russian Physics Journal - A method for modification of calcium-phosphate coatings, formed by microarc oxidation, with Fe–Cu nanocomposite bicomponent particles is proposed. The effect of... 相似文献
104.
Optics and Spectroscopy - A rigorous theory of the propagation of an electromagnetic wave that is emitted by a point elementary current source and that is focused by a flat layer filled with a... 相似文献
105.
Dapeng Liu Binod R. Giri Milán Szőri Béla Viskolcz Et-touhami Es-sebbar Aamir Farooq 《Proceedings of the Combustion Institute》2021,38(1):967-976
NOx mitigation is a central focus of combustion technologies with increasingly stringent emission regulations. NOx can also enhance the autoignition of hydrocarbon fuels and can promote soot oxidation. The reaction between allyl radical (C3H5) and NOx plays an important role in the oxidation kinetics of propene. In this work, we measured the absolute rate coefficients for the redox reaction between C3H5 and NOx over the temperature range of 1000–1252 K and pressure range of 1.5–5.0 bar using a shock tube and UV laser absorption technique. We produced C3H5 by shock heating of C3H5I behind reflected shock waves. Using a Ti:Sapphire laser system with frequency quadrupling, we monitored the kinetics of C3H5 at 220 nm. Unlike low-temperature chemistry, the two target reactions, C3H5 + NO → products (R1) and C3H5 + NO2 → products (R2), exhibited a strong positive temperature dependence for this radical-radical type reaction. However, these reactions did not show any pressure dependence over the pressure range of 1.5–5.0 bar, indicating that the measured rate coefficients are close to the high-pressure limit. The measured values of the rate coefficients resulted in the following Arrhenius expressions (in unit of cm3/molecule/s):To our knowledge, these are the first high-temperature measurements of allyl + NOx reactions. The reported data will be highly useful in understanding the interaction of NOx with resonantly stabilized radicals as well as the mutual sensitization effect of NOx on hydrocarbon fuels. 相似文献
106.
Odinokov S. B. Kolyuchkin V. V. Kuz’min D. V. Talalaev V. E. Khanevich P. A. Smirnov A. V. Smirnov L. I. 《Optics and Spectroscopy》2021,129(5):547-553
Optics and Spectroscopy - The scope of problems of embedding personal data when copying holograms on a photopolymer substrate with the maximum preservation of the region of a hologram during its... 相似文献
107.
108.
Tikhonov A. M. Asadchikov V. E. Volkov Yu. O. Roshchin B. S. Ermakov Yu. A. 《JETP Letters》2021,114(10):620-624
JETP Letters - The spectral properties of the correlation function of the heights of interlayer boundaries in a lamellar 1,2‑distearoyl-sn-glycero-3-phosphocholine film deposited on the... 相似文献
109.
The present study was undertaken to investigate the individual and combined antioxidant or prooxidant effects of genistein, daidzein and quercetin in human erythrocytes and rat microsomes in vitro. Their reducing potential against oxidation of a redox sensitive fluorescent probe, their protective effect against H2O2-induced membrane lipid peroxidation and their inhibitory effect on AAPH-induced hemolysis were evaluated. Genistein and daidzein were prooxidant in erythrocytes but antioxidant in microsomes where their metabolites might have been formed which suggests the importance of metabolic capacity in in vitro models to predict the physiological situation. Quercetin showed antioxidant effects in all models and conditions. Prooxidant effect of ‘genistein–daidzein mixture’, at their concentrations reflecting the real life, was suppressed by addition of quercetin to the mixture. Our study shows that flavonoids can exert prooxidant effects depending on the conditions, but the mixture effect should be considered while assessing their effects and safety in humans. 相似文献
110.
S. V. Partsevskaya T. B. Zheltonozhskaya D. O. Klymchuk 《Molecular Crystals and Liquid Crystals》2018,671(1):128-139
AbstractA series of amphiphilic MOPEO-b-PCL copolymers (DBCs), based on biocompatible methoxypoly(ethylene oxide) with Mn=4.5?kDa and poly(ε-caprolactone) of a variable chain length, was synthesized by an anionic ring-opening block copolymerization. The structural investigations, performed by DSC and WAXS methods, revealed the microphase separation in DBC bulk structure and the existence of separate amorphous regions and microcrystalline domains of MOPEO and PCL blocks. Spectrophotometry and SLS were used to study the self-assembling of DBC macromolecules in selective dioxane/aqueous solution and to determine the main micellization parameters (CMC and -ΔG°). The DBC micelles morphology and their specific aggregation in mixed solvent were shown. 相似文献