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61.
Y. G. Baklagina V. V. Klechkovskaya S. V. Kononova V. A. Petrova D. N. Poshina A. S. Orekhov Y. A. Skorik 《Crystallography Reports》2018,63(3):303-313
This work describes the analysis of the crystal structures of chitosan, its main polymorphic modifications, and its characteristic mutual chain packing and hydrogen bond systems in the crystalline regions of conformers. The analysis takes into consideration the crystal structures of chitosan complexes (salts) with organic and inorganic acids and their structural transformations. Notably, the transformation of the hydrated form of chitosan into anhydrous is found to be irreversible and occurs either at high temperatures or through a less stable form of hydrated salts. The interaction with polyanions during the formation of multilayer films can be considered as a way to form the anhydrous crystalline form of chitosan. 相似文献
62.
Nina Melnikova Dmitry Orekhov Alexander Simagin Darina Malygina Vitaly Korokin Karina Kosmachova Haider Al-Azzavi Anna Solovyeva Oleg Kazantsev 《Molecules (Basel, Switzerland)》2022,27(18)
The synthesis of two new copolymer conjugates of methoxyoligo(ethylene glycol)methacrylate MPEGMA and betulin methacrylate BM was developed via RAFT polymerization. The molar content of BM units was equal to 9–10 and 13–16 mol%, respectively (HPLC, 1H and 13C NMR); molar weights were equal to 75000–115000. CeO2 NPs as a component of the hybrid material were synthesized for the preparation of the composition with copolymer conjugates of MPEGMA and BM. We showed a significant increase in G6PDH and GR activities by 21–51% and 9–132%, respectively, which was due to the increase in NADPH concentration under the action of copolymers in vitro. The actions of copolymers and CeO2 NPs combination were stronger than those of the individual components: the SOD activity increased by more than 30%, the catalase activity increased dose-dependently from 13 to 45%, and the GR activity increased to 49%. The maximum increase in enzyme activity was observed for the G6PDH from 54% to 151%. The MDA level dose-dependently increased by 3–15% under the action of copolymers compared with the control, and dose-dependently decreased by 3–12% in samples containing CeO2 NPs only. CeO2 NP–copolymer compositions can be used for the design of new biomimetic medical products with controlled antioxidant properties. 相似文献
63.
Danov S. M. Fedosov A. E. Lunin A. V. Orekhov S. V. Fedosova M. E. 《Russian Journal of Applied Chemistry》2010,83(11):2062-2064
Data on the effect of the type and intensity of irradiation on the basic characteristics of the process and distribution of
products of catalytic liquid-phase oxidation of hydrocarbons were obtained using as an example the oxidation of n-dodecane by hydrogen peroxide aqueous solutions on the heterogeneous catalyst: titanium silicalite. 相似文献
64.
Yu. A. D’yakova E. I. Suvorova A. S. Orekhov A. S. Alekseev V. V. Klechkovskaya E. Yu. Tereshchenko N. V. Tkachenko H. Lemmetyinen L. A. Feigin M. V. Kovalchuk 《Crystallography Reports》2011,56(1):157-163
Monolayers of porphyrin-fullerene dyad TBD6a were formed on the surface of a water subphase and then transported on a solid
substrate by the Langmuir-Schaefer method. A simulation was performed for the structure of a single molecule and for a molecular
monolayer, according to the area per molecule in the monolayer formed, which was calculated based on an analysis of the π-A
isotherm. A unit cell was chosen for the proposed molecular packing (a = 1.54 nm, b = 1.50 nm, c = 1.75 nm, α = 80.0°, β = 90.0°, and γ = 90.0°), and the atomic coordinates were calculated. A comparison of the interplanar
spacings and diffraction peak intensities in the experimental and calculated (for the unit cell proposed) diffraction patterns
indicates that a platelike texture is formed in the monolayer and that the crystal structure of the domains corresponds to
the model chosen. 相似文献
65.
O. A. Kazantsev A. P. Sivokhin S. I. Samodurova D. M. Kamorin D. V. Orekhov 《Russian Journal of Applied Chemistry》2012,85(5):804-811
Copolymerization of higher N-alkylacrylamides of various structures with butyl acrylate and butyl methacrylate in organic solvents was studied. 相似文献
66.
V. A. Petrova A. S. Orekhov D. D. Chernyakov Yu. G. Baklagina D. P. Romanov S. V. Kononova A. V. Volod’ko I. M. Ermak V. V. Klechkovskaya Yu. A. Skorik 《Crystallography Reports》2016,61(6):945-953
A method for preparing multilayer film composites based on chitosan has been developed by the example of polymer pairs: chitosan–hyaluronic acid, chitosan–alginic acid, and chitosan–carrageenan. The structure of the composite films is characterized by X-ray diffractometry and scanning electron microscopy. It is shown that the deposition of a solution of hyaluronic acid, alginic acid, or carrageenan on a chitosan gel film leads to the formation of a polyelectrolyte complex layer at the interface, which is accompanied by the ordering of chitosan chains in the surface region; the microstructure of this layer depends on the nature of contacting polymer pairs. 相似文献
67.
68.
D. A. Orekhov V. A. Volodin M. D. Efremov A. I. Nikiforov V. V. Ul’yanov O. P. Pchelyakov 《JETP Letters》2005,81(7):331-334
Multilayer structures with germanium nanoislands that are formed on the silicon (111) surface upon submonolayer deposition by molecular-beam epitaxy have been investigated using Raman spectroscopy. To interpret the experimental Raman spectra, numerical calculations of the spectra have been performed for nanoislands containing from several to several hundred germanium atoms. The calculations demonstrate that the in-plane sizes of nanoislands (with sizes less than 2–3 nm) substantially affect the frequencies of phonons localized in these nanoislands. The experimental Raman spectra confirm the occurrence of the quantum size effect. 相似文献
69.
T.N. Kol'tsova G.D. Nipan N.F. Vedernikov Yu.F. Orekhov E.A. Tishchenko 《Superlattices and Microstructures》1997,22(4):617-621
The annealing of YBa2CuzO7−δcompounds (2.5 ≤ z ≤ 3.5) in oxygen flow (at temperature of synthesis and following fast cooling) leads to: (i) a reduction in homogeneity range; (ii) decreasing of copper content influence on superconducting properties of samples; (iii) considerable decreasing of ΔTcvalue as a result of cation and anion vacancies order. 相似文献
70.
V. A. Volodin E. B. Gorokhov M. D. Efremov D. V. Marin D. A. Orekhov 《JETP Letters》2003,77(8):411-414
Germanium nanocrystals were formed in a GeO2 film during the process of germanium monoxide gas-phase deposition onto a sapphire substrate and studied by photoluminescence (PL) and Raman scattering spectroscopy. A PL peak in this heterosystem was observed in the visible region at room temperature. The sizes of Ge nanocrystals were estimated from the position of a Raman peak corresponding to scattering by localized optical phonons in germanium. The PL peak position calculated with allowance for the electron and hole size quantization in Ge nanocrystals coincides well with the experimentally observed position of this peak. 相似文献