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11.
V. B. Rogacheva O. A. Novoskol’tseva A. B. Zezin J. Joosten J. Brackman 《Polymer Science Series A》2007,49(9):1000-1007
Competitive interactions in ternary systems including a lightly crosslinked polyanionic hydrogel, a protonated Astramol? poly(propylene imine) dendrimer (of first to fifth generation), and an ionic surfactant were studied. It was found that the direction of the substitution reactions in systems containing cationic surfactants depends on the length of the aliphatic radical in the surfactant molecule as well as on the dendrimer generation number. Depending on these parameters, the interpolyelectrolyte complex formed by the network polyanion and the cationic dendrimer is either capable or incapable of sorbing surfactant cations from aqueous solutions, thereby transforming into the network polyanion-cationic surfactant complex with the release of dendrimers to the surrounding solution. It was shown that the substitution reaction in systems containing anionic surfactants leads to the formation of a polyanionic gel reinforced by particles of the dendrimer-anionic surfactant complex. 相似文献
12.
Kh. I. Mamedov M. M. Khalilov A. A. Chervova V. O. Shestopal I. S. Filatov V. N. Mochalkin E. G. Povoltskii Yu. I. Surov G. A. Vartanova A. S. Kuz'min G. G. Beloliptseva D. I. Vaisburd É. U. Umetov A. A. Alybakov L. S. Gutyrya V. D. Iskra L. V. Gorchakov N. F. Kovalenko V. I. Yakimenko A. G. Smagin P. B. Podosenov B. M. Adibaev N. D. Kosov V. P. Sevryuk V. P. Sevryuk N. D. Tokarev G. P. Yarovoi Ya. Ya. Yurike S. S. Rogacheva V. I. Danilova E. E. Sirotkina V. P. Sevryuk V. P. Sevryuk 《Russian Physics Journal》1974,17(6):896-903
13.
R Nirmala V Sankaranarayanan K Sethupathi AV Morozkin T Geethakumary Y Hariharan 《Pramana》2002,58(5-6):1101-1104
New R
2Ti3Ge4 (R=Dy, Ho and Er) intermetallic compounds have been synthesized and characterized by X-ray diffraction and low temperature ac
magnetic susceptibility, electrical resistivity and thermoelectric power measurements were carried out. The compounds crystallize
in the parent, Sm5Ge4-type orthorhombic structure (space group Pnma) and lanthanide contraction is observed as one moves along the rare-earth series.
The changeover from paramagnetic to antiferromagnetic phase happens at low temperatures and the ordering temperature scales
with the de Gennes factor. The electrical resistivity is metallic with a negative curvature above 100 K. Thermopower displays
a weak maximum at temperatures less than 50 K signifying the possible phonon and magnon drag effects. 相似文献
14.
M. F. Zansokhova V. B. Rogacheva Zh. G. Gulyaeva A. B. Zezin J. Joosten J. Brackman 《Polymer Science Series A》2008,50(6):656-664
The interaction of ampholyte propylenimine dendrimers containing peripheral carboxyl groups and inner tertiary amino groups with linear polyelectrolytes has been studied. Both in acidic and alkaline media up to pH ~ pI, dendritic polyampholytes can form interpolyelectrolyte complexes with flexible linear polyanions and polycations. A variation in the composition of complexes with a change in pH is associated with the formation of intramolecular zwitterion pairs in a dendrimer molecule. The ability of interpolyelectrolyte complexes to dissolve in water is shown to be determined by the degree of dissociation of ionogenic groups of the dendrimer not directly involved in the formation of interpolyelectrolyte salt bonds stabilizing the complex. It has been demonstrated that the territorial separation of carboxyl and tertiary amino groups in the polyampholyte dendrimers is reflected in different structures of interpolyelectrolyte complexes formed by dendrimers with oppositely charged linear polyions. 相似文献
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17.
O. A. Novoskol’tseva V. D. Astakhova E. V. Chernikova V. B. Rogacheva A. B. Zezin 《Polymer Science Series A》2011,53(12):1141-1149
The interaction of amphiphilic block copolymers comprising an anionic block (polyacrylate or polymethacrylate) and a hydrophobic
block (polystyrene, poly(butyl acrylate) or polyisobutylene) with lightly crosslinked poly(N,N-diallyl-N,N-dimethylammonium chloride) is studied for the first time. It is shown that the cationic hydrogel can sorb anionic amphiphilic
block copolymers via electrostatic interaction with the corona of block copolymer micelles. The rate of sorption of block
copolymer polyelectrolytes is significantly lower than the rate of sorption of linear polyions and is controlled by the lengths
of the hydrophilic and hydrophobic blocks and the flexibility of the latter blocks. The sorption of amphiphilic block copolymers
is accompanied by their self-assembly in the polycomplex gel and formation of a continuous hydrophobic layer impermeable to
water and the low-molecular-mass salt dissolved in it. 相似文献
18.
Fedotov VA Mladyonov PL Prosvirnin SL Rogacheva AV Chen Y Zheludev NI 《Physical review letters》2006,97(16):167401
We report that normal incidence transmission of circularly polarized waves through the lossy anisotropic planar chiral structure is asymmetric in the opposite direction. The new effect is fundamentally distinct from conventional gyrotropy of bulk chiral media and the Faraday effect, where the eigenstates are a pair of counterrotating elliptical states, while the eigenstates of the lossy anisotropic planar chiral structure are two corotating elliptical polarizations. 相似文献
19.
Shell theory equations are constructed by the method in [1] to the accuracy of quantities of the order of h*2+k, where
and k = 2−4t for
(h* is the relative semithickness of the shell and t is the index of the state of stress variation). Without being within the framework of the Lovetype theory, the equations obtained are compared with the Reissner-Naghdi equations. [2, 3] in which the transverse shear is taken into account, and it is shown that from the asymptotic viewpoint these latter are inconsistent. It is also shown that if the shell resists shear weakly, then from the asymptotic viewpoint the Reissner-Naghdi theory is completely well founded.The three-dimensional equations of elasticity theory are reduced to two-dimensional equations in [1] by using an asymptotic method, i.e. all members of the same order relative to the small parameter h* are taken into account at each stage of the calculations. It has been shown that without going outside the framework of the ordinary concepts of the Love-type theory of shells (in particular, without taking account of transverse shear), the shell theory equations can be constructed to the accuracy of quantities of the order of h2−2t*, but it is impossible to exceed this limit without a qualitative complication in the theory. 相似文献
20.
Rogacheva MV Bochenkova AV Kuznetsova SA Saparbaev MK Nemukhin AV 《The journal of physical chemistry. B》2007,111(2):432-438
Design of novel DNA probes to inhibit specific repair pathways is important for basic science applications and for use as therapeutic agents. As shown previously, single pyrophosphate (PP) and O-ethyl-substituted pyrophosphate (SPP) modifications can inhibit the DNA glycosylase activities on damaged DNA. To understand the structural basis of this inhibition, the influence of the PP and SPP internucleotide groups on the helical parameters and geometry of a double-stranded DNA was studied by using molecular modeling tools including molecular dynamics and quantum mechanical-molecular mechanical (QM/MM) approaches. Native and locally modified PP- and SPP-containing DNA duplexes of dodecanucleotide d(C1G2C3G4A5A6T7T8C9G10C11G12) were simulated in aqueous solution. The energies and forces were computed by using the PBE0/6-31+G** approach in the QM part and the AMBER force-field parameters in the MM part. Analysis of the local base-pair helical parameters, internucleotide distances, and overall global structure at the located stationary points revealed a close similarity of the initial and modified duplexes, with only torsion angles of the main chain being altered in the vicinity of introduced chemical modification. Results show that the PP and SPP groups are built into a helix structure without elongation of the internucleotide distance due to flipping-out of phosphate group from the sugar-phosphate backbone. The mechanism of such embedding has only a minor impact on the base pairs stacking and Watson-Crick interactions. Biochemical studies revealed that the PP and SPP groups immediately 5', but not 3', to the 8-oxoguanosine (8oxodG) inhibit translesion synthesis by a DNA polymerase in vitro. These results suggest that subtle perturbations of the DNA backbone conformation influence processing of base lesions. 相似文献