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1.
Nikolina L. Petrova Dimitar S. Todorovsky Veselinka G. Vasileva 《Central European Journal of Chemistry》2005,3(2):263-278
Mn-, LaMn- and LaCaMn-citrates were synthesized at 60–120°C in ethylene glycol medium using chlorides or nitrates as metal
sources. Their composition, IR spectra and thermal decomposition were studied. Equimolar La/Mn ratio has been established
in the complex, prepared from chloride solution with the same initial composition of the metals. In the isolated three-metallic
complex the molar ratio of the metals deviates from the composition in the initial solution. The final products of the heating
of Mn- and mixed-metal LaMn-citrates at 1000°C are phase-homogeneous Mn3O4 (hausmannite) and LaMnO3 respectively. Parasitic phase(s) are observed in LaxCa1−xMnyO3, produced from LaCaMn-citrate. 相似文献
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A sensitive and rapid magnetic nanoparticle-based fluorescent immunoassay for the determination of aflatoxin M1 in raw milk was developed. Aflatoxin M1 was converted to aflatoxin M1-o-carboxymethyl oxime. The aflatoxin M1-oxime was used for the preparation of aflatoxin M1-oxime-fluoresceinamine conjugate through the carbodiimide reaction. The aflatoxin M1-oxime-fluoresceinamine conjugate was characterized by ultraviolet–visible and infrared spectroscopy. Magnetic nanoparticles (Fe3O4) were synthesized and modified by 3-(aminopropyl)triethoxysilane. The size of initial (139?nm) and functionalized magnetic nanoparticles (147?nm) was determined by particle analysis. The optimal mass of immobilized antibody (25?µg) and optimal concentration of aflatoxin M1-oxime-fluoresceinamine conjugate (15?µg?mL?1) for magnetic nanoparticle-based fluorescent immunoassay were determined. The developed immunoassay provided a linear aflatoxin M1 concentration range from 3.0 to 100?pg?mL?1 in bovine milk. The detection limit was 2.9?pg?mL?1. The results of aflatoxin M1 magnetic nanoparticle-based fluorescent immunoassay in heat-treated milk and phosphate-buffered saline at pH 6.6 were compared. The influence of the somatic cell count, pH, and fat concentration in bovine milk on the aflatoxin M1 immunoassay was investigated. The influence of the milk species on the immunoassay was also characterized. The high fat concentration ovine milk depressed the sensitivity of the aflatoxin M1 immunoassay. 相似文献
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Jianzhong Zhu I. G. Vasileva J. I. Gibner T. Y. Shilkina Z. I. Boris 《Fresenius' Journal of Analytical Chemistry》1992,342(4-5):363-366
Summary An apparatus for the selective dissolution as a chemical method of phase analysis and its operating conditions are described. Using ICP-AES as determination method an example for the YBCO system is found in the phase YBa2–0.04Cu3+0.03Ox and a BSCCO system is found in three phases of 35.6% Bi2(Sr,Ca)4–0.08Cu3–0.05Ox, 30.1% Bi2(Sr,Ca)3–0.09Cu2–0.08Ox and 34.3% Bi2(Sr,Ca)2–0.07Cu1–0.05Ox. 相似文献
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Vasileva L. A. Kuznetsova D. A. Valeeva F. G. Vasilieva E. A. Lukashenko S. S. Gaynanova G. A. Zakharova L. Ya. 《Russian Chemical Bulletin》2021,70(7):1341-1348
Russian Chemical Bulletin - A homologous series of cationic surfactants with a pyrrolidinium head group containing a hydroxyethyl moiety was studied for the solubilization of nonsteroidal... 相似文献
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F. D. Vasileva A. N. Kapitonov A. E. Tomskaya S. A. Smagulova 《Journal of Structural Chemistry》2018,59(4):823-829
An aqueous suspension of graphite oxide (GrO) was prepared from natural Yakut graphite by modified Hummers′ method. The lateral size of GrO flakes varied from 0.1 μm to 10 μm, their thickness was 20 nm. The fabricated suspension, GrO films (of various thickness and on various substrates), and GrO papers were studied in terms of their structural, optical, and electrophysical characteristics. The obtained GrO films are dielectrics with quite large resistance varying from 12.5.106–4.6.109 Ω depending on their thickness. The films are characterized by the luminescence in the region of 380–650 nm, the presence of oxygen-containing groups–ОН,–СООН,–С=О,–СОН, СОО–, and the transparency of 91% for a 20 nm thick film at the wavelength of 670 nm. The conducted study testifies high quality of Yakut graphite, which can be quite easily exfoliated. GrO films possess high resistance and transparency. 相似文献
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V. L. Novikov O. P. Shestak N. P. Mishchenko S. A. Fedoreev E. A. Vasileva V. P. Glazunov A. A. Artyukov 《Russian Chemical Bulletin》2018,67(2):282-290
The nondestructive oxidation of 7-ethyl-2,3,5,6,8-pentahydroxy-1,4-naphthoquinone by atmospheric oxygen in the ground (triplet 3Σg–) and excited (singlet 1Δg) states in different solvents (acetone, dioxane, ethanol, aqueous ethanol, water) at room temperature involves the initial formation of 7-ethyl-5,6,8-trihydroxy-2,3-dioxo-2,3-dihydro-1,4-naphthoquinone (dehydroechinochrome) accompanied by the release of an H2O2 molecule into the reaction medium. Dehydroechinochrome, being highly susceptible to hydration, successively reacts with two H2O molecules to form 7-ethyl-2,2,3,3,5,6,8-heptahydroxy-2,3-dihydro- 1,4-naphthoquinone as the relatively stable final product. In this form, it can be isolated from the mixture of reaction products. 相似文献
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Ershov A. Yu. Vasileva M. Yu. Lagoda I. V. Yakimansky A. V. 《Russian Journal of General Chemistry》2018,88(6):1199-1204
Russian Journal of General Chemistry - The structure of the condensation products of D-lactose and D-maltose with sulfanylacetic, 3-sulfanylpropanoic, and 2-sulfanylbenzoic acid hydrazides has been... 相似文献
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Natalia A. Danilkina Ekaterina V. Andrievskaya Anna V. Vasileva Anna G. Lyapunova Andrey M. Rumyantsev Andrey A. Kuzmin Elena A. Bessonova Irina A. Balova 《Molecules (Basel, Switzerland)》2021,26(24)
A new type of fluorogenic and fluorochromic probe based on the reduction of weakly fluorescent 4-azido-6-(4-cyanophenyl)cinnoline to the corresponding fluorescent cinnoline-4-amine was developed. We found that the fluorescence of 6-(4-cyanophenyl)cinnoline-4-amine is strongly affected by the nature of the solvent. The fluorogenic effect for the amine was detected in polar solvents with the strongest fluorescence increase in water. The environment-sensitive fluorogenic properties of cinnoline-4-amine in water were explained as a combination of two types of fluorescence mechanisms: aggregation-induced emission (AIE) and excited state intermolecular proton transfer (ESPT). The suitability of an azide–amine pair as a fluorogenic probe was tested using a HepG2 hepatic cancer cell line with detection by fluorescent microscopy, flow cytometry, and HPLC analysis of cells lysates. The results obtained confirm the possibility of the transformation of the azide to amine in cells and the potential applicability of the discovered fluorogenic and fluorochromic probe for different analytical and biological applications in aqueous medium. 相似文献