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191.
The NMR spectra of finely dispersed ice were investigated. It is shown that the narrow NMR signal from the ice is caused by the mobile water molecules on the ice-gas and iceteflon interfaces. The mobile water phase is in comparatively steady quasi-equilibrium with the strongly defective structure of the bulk ice. The relation of the superficial ice properties with the size of the ice grain is discussed. 相似文献
192.
I. N. Flerov M. V. Gorev M. L. Afanas’ev T. V. Ushakova 《Physics of the Solid State》2001,43(12):2301-2306
The heat capacity of (NH4)2KGaF6 elpasolite is measured in the temperature range from 80 to 350 K. A sequence of three phase transitions at T 1=288.5 K, T 2=250 K, and T 3=244.5 K is revealed, and the thermodynamic characteristics of these transitions are determined. The influence of hydrostatic pressure on the phase transition temperature is investigated. The results obtained are discussed within the model of orientational ordering of NH 4 + and GaF 6 3? ionic groups. 相似文献
193.
Olga Zhytniakivska Valeriya Trusova Galyna Gorbenko Elena Kirilova Inta Kalnina Georgiy Kirilov Julian Molotkovsky Jukka Tulkki Paavo Kinnunen 《Journal of fluorescence》2014,24(3):899-907
Förster resonance energy transfer (FRET) between anthrylvinyl-labeled phosphatidylcholine (AV-PC) as a donor and newly synthesized benzanthrones (referred to here as A8, A6, AM12, AM15 and AM18) as acceptors has been examined to gain insight into molecular level details of the interactions between benzanthrone dyes and model lipid membranes composed of zwitterionic lipid phosphatidylcholine and its mixtures with anionic lipids cardiolipin (CL) and phosphatidylglycerol (PG). FRET data were quantitatively analyzed in terms of the model of energy transfer in two-dimensional systems taking into account the distance dependence of orientation factor. Evidence for A8 location in phospholipid headgroup region has been obtained. Inclusion of CL and PG into PC bilayer has been found to induce substantial relocation of A6, AM12, AM15 and AM18 from hydrophobic membrane core to lipid-water interface. 相似文献
194.
Kateryna Vus Valeriya Trusova Galyna Gorbenko Rohit Sood Elena Kirilova Georgiy Kirilov Inta Kalnina Paavo Kinnunen 《Journal of fluorescence》2014,24(2):493-504
A series of novel fluorescent benzanthrone dyes have been tested for their ability to identify and characterize fibrillar aggregates of lysozyme prepared by protein denaturation in concentrated ethanol solution (Feth) or acidic buffer (Fac). Quantitative parameters of the dye association with native and fibrillar protein have been derived from the results of fluorimetric titration. The binding characteristics proved to be different for Feth- and Fac-bound benzanthrones, highlighting the dye sensitivity to the distinctions in fibril morphology. By comparing the dye preference to fibrillar protein aggregates, AM2, A8 and A6 were selected as the most prospective amyloid tracers. Based on the analysis of red edge excitation shifts and fluorescence lifetimes of the amyloid-bound dyes it was assumed that surface grooves or dry “steric zipper” interface are potential fibril binding sites for the novel fluorophores. 相似文献
195.
N. N. Chipanina L. P. Oznobikhina I. V. Ushakova B. A. Shainyan 《Russian Journal of Organic Chemistry》2013,49(7):999-1003
The electronic structures and basicities of trifluoro-N-methyl-N-(2-phenylethenyl)methanesulfonamide, N-methyl-2-phenylethenamine, trifluoro-N-methylmethanesulfonamide, and their C-, N-, and O-protonated forms and H-complexes were studied at the B3LYP/6–311+G** and MP2/cc-pVTZ levels of theory. The basicity of the double bond in trifluoro-N-methyl-N-(2-phenylethenyl)methanesulfonamide is much lower than that in N-methyl-2-phenylethenamine, and its protonation is possible only in trifluoromethanesulfonic acid. 相似文献
196.
Kutsenko OK Trusova VM Gorbenko GP Deligeorgiev T Vasilev A Kaloianova S Lesev N 《Journal of fluorescence》2011,21(4):1689-1695
The interaction between Eu(III) tris-β-diketonato coordination complexes (EC), displaying antitumor activity, and lipid vesicles
composed of zwitterionic lipid phosphatidylcholine has been studied using fluorescence spectroscopy techniques. To characterize
EC-membrane binding, several fluorescent probes, including pyrene, Prodan and 1,6-diphenyl-1,3,5-hexatriene, have been employed.
It has been found that EC display effective partitioning into lipid phase, giving rise to structural modifications of both
polar and nonpolar lipid bilayer regions, viz. enhancement of membrane hydration and increase in tightness of lipid chain
packing. The fact that EC accumulating in lipid bilayer are incapable of inducing significant disruption of membrane structural
integrity creates strong prerequisites for development of liposomal nanocarriers of these potential antitumor drugs. Such
a possibility is also corroborated by the observation that EC membrane incorporation does not prevent lipid bilayer partitioning
of long-wavelength squaraine dyes which represent promising candidates for visualization of liposome biodistribution. 相似文献
197.
E. N. Govorun A. S. Ushakova A. R. Khokhlov 《The European physical journal. E, Soft matter》2010,32(3):229-242
A microphase separation in solutions containing a polymer and a mixture of two solvents, one of which consists of amphiphilic
molecules (surfactant), is considered theoretically in the weak-segregation regime. A surfactant molecule is described as
a dimer consisting of hydrophobic and polar parts. The energy gain due to the orientation of surfactant molecules can lead
to the appearance of non-homogeneities in the solution, where density fluctuations cause the orientational ordering of surfactant
molecules. The difference in the interaction energies of hydrophobic and polar groups of a surfactant with solvent is considered
as a main reason for orienting surfactant molecules. The free energy is calculated for various morphologies (lamellar, cylindrical
hexagonal, spherical particles arranged at different cubic lattices). The phase diagrams are presented. With worsening the
solvent quality, the transitions from disordered to a macro-separated state at low polymer and surfactant concentrations or
to a body-centered-cubic, then hexagonal, and then lamellar structure at high polymer and surfactant concentrations are predicted.
The amphiphilicity degree of surfactant molecules should exceed a certain critical value to make a microstructure formation
possible. The period of the lamellar microstructure decreases with increasing the surfactant and polymer concentrations. 相似文献
198.
D. A. Volgina E. A. Stepanidenko T. K. Kormilina S. A. Cherevkov A. Dubavik M. A. Baranov A. P. Litvin A. V. Fedorov A. V. Baranov K. Takai P. S. Samokhvalov I. R. Nabiev E. V. Ushakova 《Optics and Spectroscopy》2018,124(4):494-500
The interaction of gold nanoparticles (NPs) and semiconductor alloyed CdZnSe/ZnS quantum dots (QDs) in colloidal solutions is studied. It is shown that the photoluminescence intensity of QDs in a mixture decreases compared to that in the initial QD solution, which is caused by resonance nonradiative energy transfer from QDs to Au NPs in spontaneously formed aggregates. To control the formation of pairs of interacting QDs and Au NPs, we proposed have a method for creating QD–Au NP complexes bound by special molecules—ligands. It is shown that the morphology and optical properties of the samples obtained depend on the method of their preparation, in particular, on the chemical environment of QDs. It is found that the complexes form in the case of addition of hydrophilic Au NPs to hydrophobic QDs and that this almost does not change the optical properties of the latter compared to those of quasi-isolated QDs in colloidal solution. 相似文献
199.
Galyna P. Gorbenko Valeriya Trusova Chiharu Mizuguchi Hiroyuki Saito 《Journal of fluorescence》2018,28(5):1037-1047
The effects of one of the amyloidogenic mutations of apolipoprotein A-I (apoA-I), G26R, on the thermal stability, structural dynamics and lipid-associating properties of the 1–83 N-terminal fragment of apoA-I (A83) have been investigated using the Förster resonance energy transfer (FRET) and molecular dynamics (MD) simulation. The measurements of FRET between the tryptophan residues of the single Trp variants of A83 as donors and the membrane-incorporated fluorescent probe 4-dimethylaminochalcone as an acceptor provided evidence for a less depth of A83/G26R penetration into phosphatidylcholine (PC) bilayer compared to WT counterpart. The unfolding MD simulations showed that G26R mutation destabilizes the overall structure of A83, with individual alpha-helices differing in their thermal stability. The MD simulations performed at physiological temperature revealed that A83 and A83/G26R differ in their conformational behavior in an aqueous solution, PC and PC/Cholesterol bilayers. These findings may prove of importance for deeper understanding of the key determinants of apoA-I amyloidogenesis. 相似文献
200.
Lyudmila Novokshonova Natalia Kovaleva Irina Meshkova Tatiana Ushakova Vadim Krasheninnikov Tatiana Ladygina Ilia Leipunskii Alexey Zhigach Michail Kuskov 《Macromolecular Symposia》2004,213(1):147-156
Heterogenized activators - “support-H2O/AlR3” (where R=Me, iBu, support=montmorillonite, zeolite), synthesized directly on the support, form with metallocenes metal alkyl complexes highly active in olefin polymerization without the use of commercial methylaluminoxane (MAO). It was shown by the method of temperature programmed desorption with the application of mass-spectrometry (TPD-MS) that the aluminumorganic compound in support-H2O/AlR3 is in general similar to the structure of commercial MAO. The heterogenization of Zr-cenes on support-H2O/AlR3 is accompanied by the appearance of the energy non-uniformity of active sites. The activation energy of thermal destruction of active Zr-C bonds in the active sites of prepared catalysts changes in the range from 25 to 32 kcal/mol. 相似文献