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G. Veinberg R. Bokaldere K. Dikovskaya M. Vorona I. Kanepe I. Shestakova E. Yashchenko E. Lukevics 《Chemistry of Heterocyclic Compounds》2003,39(5):587-593
A series of 1,3,4-trisubstituted and 3,4-disubstituted 2-azetidinones were synthesized in order to study the relation between their structure and biological characteristics. Study of the cytotoxic activity of these compounds revealed an anticancer effect in (3S,4S)-1-(4-methoxyphenyl)-3-methyl-2-azetidinones containing 2-acetoxybenzoyloxymethyl and 2,2-dicyanovinyl substituents at position 4 in vitro with respect to a wide range of monolayer cultures of cancer cells. 相似文献
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G. Veinberg M. Vorona D. Musel R. Bokaldere I. Shestakova I. Kanepe E. Lukevics 《Chemistry of Heterocyclic Compounds》2004,40(6):816-822
4-Sulfonylazetidinones-2 were synthesized by the reaction of DBU and organic halides on the esters of penicillin sulfones. 4-Sulfonylthio- and 4-sulfothioazetindinones-2 were synthesized by nucleophilic substitution of the 2-benzothiazolylthio groups in 4-(benzothiazolylthio)azetidinones-2 using sodium sulfinates or sodium hydrogen sulfite. A study of their cytotoxic activities revealed the anticancer effect of compounds containing methylsulfonylthio-, 4-tolylsulfonylthio-, and 4-methoxycarbonylamino-phenylsulfonylthio-substituents at position 4 of the -lactam ring relative to a wide range of monolayer cultures of cancer cells in vitro. 相似文献
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Yu. Melnik M. Vorona G. Veinberg J. Popelis L. Ignatovich E. Lukevics 《Chemistry of Heterocyclic Compounds》2005,41(6):718-721
2-(1-Alkoxyimino-2,2,2-trifluoroethyl)-5-trimethylsilylfurans were synthesized by the condensation of 2-(trifluoroacetyl)-5-trimethylsilylfuran
with alkoxyamines. According to 1H and 19F NMR spectroscopic data, the alkoxyimino group in the E-isomers descreens the H-3 and H-4 protons of the furan ring more strongly than in the Z-isomers, shifting their signals downfield. The fluorine atoms of the α-trifluoromethyl group in the Z-isomer are characterized by a downfield shift in relation to the E-isomer.
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Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 834–838, June, 2005. 相似文献
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N. N. Antonov N. A. Vorona A. V. Gavrikov A. A. Samokhin V. P. Smirnov 《Technical Physics》2016,61(2):180-186
Plasma sources of model substances are required for solving problems associated with the development of a plasma separation method for spent nuclear fuel (SNF). Lead is chosen as the substance simulating the kinetics and dynamics of the heavy SNF component. We report on the results of analysis of the discharge in lead vapor with a concentration of 1012–1013 cm–3. Ionization is produced by an electron beam (with electron energy up to 500 eV) in the centimeter gap between planar electrodes. The discharge is simulated using the hydrodynamic and one-particle approximations. The current–voltage characteristics and efficiencies of single ionization depending on the vapor concentrations and thermoelectron current are obtained. The experimentally determined ion currents on the order of 100 μA for an ionization efficiency on the order of 0.1% are in conformity with the result of simulation. 相似文献
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Vorona I. P. Ishchenko S. S. Baran N. P. Rudko V. V. Zatovski? I. V. Gorodilova N. A. Povarchuk V. Yu. 《Physics of the Solid State》2010,52(11):2364-2368
Physics of the Solid State - The structure and properties of NO 3 2? paramagnetic complexes formed by γ-rays and UV irradiation in synthetic hydroxyapatite have been investigated using... 相似文献
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Baran N. P. Vorona I. P. Ishchenko S. S. Nosenko V. V. Zatovskii I. V. Gorodilova N. A. Povarchuk V. Yu. 《Physics of the Solid State》2011,53(9):1891-1894
The EPR studies of synthetic hydroxyapatite containing carbonate and nitrate ions exposed to γ-ray and UV irradiations have
been performed. It has been found that γ irradiation leads to the formation of both NO32− and CO2− paramagnetic centers, while the UV irradiation induces only NO32− centers. To explain this fact, the hypothesis has been proposed, according to which in the hydroxyapatites studied, there
coexist complexes consisting of nitrate ions and shallow electron traps that serve as sources of secondary electrons during
UV irradiation. The EPR spectroscopy parameters (g and A) of the detected centers have been determined and compared with similar centers in hydroxyapatite with a different impurity
composition. The study of the thermal stability of the centers has demonstrated that, in the temperature range 20–300°C, the
NO32− centers formed by UV irradiation are more stable than the same centers created by γ-ray irradiation. 相似文献
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I. P. Vorona S. S. Ishchenko N. P. Baran V. V. Nosenko I. V. Zatovskii A. I. Malyshenko V. Yu. Povarchuk 《Physics of the Solid State》2013,55(12):2543-2548
The effect of preliminary (before irradiation) annealing of synthetic carbonate-containing hydroxyapatite powders on the formation of paramagnetic centers under γ-ray and ultraviolet irradiation has been investigated. Annealing of the samples has been performed in the temperature range from 100 to 700°C. It has been found that electron paramagnetic resonance spectra of radiation-induced defects depend substantially on the annealing temperature. The paramagnetic centers CO 2 ? dominate in the samples annealed to 250°C (γ-ray irradiation) and 500°C (ultraviolet irradiation). In the samples annealed above 400°C, other defects, in particular, the O? and CO 3 3? centers, play a significant role. Annealing at some temperatures leads to an increase in the radiation sensitivity of the material. The observed effects can be associated with the escape of molecular water from the annealed hydroxyapatite samples and with the corresponding transformation of the defect subsystem of the material. 相似文献