620 research outputs found
Double-spiral magnetic structure of the Fe/Cr multilayer revealed by nuclear resonance scattering
We have studied the magnetization depth profiles in a [57Fe(dFe)/Cr(dCr)]x30
multilayer with ultrathin Fe layers and nominal thickness of the chromium
spacers dCr 2.0 nm using nuclear resonance scattering of synchrotron radiation.
The presence of a broad pure-magnetic half-order (1/2) Bragg reflection has
been detected at zero external field. The joint fit of the reflectivity curves
and Mossbauer spectra of reflectivity measured near the critical angle and at
the "magnetic" peak reveals that the magnetic structure of the multilayer is
formed by two spirals, one in the odd and another one in the even iron layers,
with the opposite signs of rotation. The double-spiral structure starts from
the surface with the almost antiferromagnetic alignment of the adjacent Fe
layers. The rotation of the two spirals leads to nearly ferromagnetic alignment
of the two magnetic subsystems at some depth, where the sudden turn of the
magnetic vectors by ~180 deg (spin-flop) appears, and both spirals start to
rotate in opposite directions. The observation of this unusual double-spiral
magnetic structure suggests that the unique properties of giant
magneto-resistance devices can be further tailored using ultrathin magnetic
layers.Comment: 9 pages, 3 figure
Comparative evaluation of the effectiveness of a peptide-containing drug and polyoxydonium in the treatment of chronic parodontitis
Currently, the available methods of treating parodontitis are not able to have a complex effect. Therefore, in recent years, there has been an active search and development of new methods of treatment and new drugs that have a complex etiopathogenetic effect on this disease. This article provides a comparative evaluation of the classical and experimental methods of treating chronic periodontitis. Based on the reconstruction of an experimental model of chronic inflammation of periodontal tissues of the Wistar rat line, we compared methods of topical therapy by “Organosilicon Glycerohydrogel – Peptide” and “Polyoxidonium” compositions. A comparative assessment of the activity of these drugs with control groups, which were treated with “Organosilicon Glycerohydrogel” and “Metrogyl Denta”, was carried out. Previously, we carried out separate studies of the effectiveness of the use of the composition “organosilicon glycerohydrogel – peptide”, as well as the method of treatment of periodontitis, by injecting the drug “Polyoxidonium”. They have been compared with the classic treatment for this disease to obtain relevant data and results. In our opinion, the data obtained are of considerable interest. The assessment and comparison of clinical and histological data have been carried out, which showed that all drugs had a positive effect on the processes of tissue regeneration. However, the composition “Organosilicon Glycerohydrogel-peptide”, due to the characteristics of the hydrogel, which is acting as a transcutaneous conductor, showed a faster antimicrobial and pathogenetic effect, which allows a comprehensive approach to solving this problem. In comparison with the groups of “Organosilicon Glycerohydrogel” and “Polyoxidonium”, the period of clinical improvement increased by 57% in the group of “Glycerohydrogel-Peptide”, and, in the “Metrogyl Denta” group, the indicators improved by 15% approximately
Study of the surface microrelief of copper nanoparticles by the method of scanning probe microscopy
This work was supported by grants from the RFBR № 17-07-00407-а and № 17-32-50137-mol_nr
Entropy as a function of Geometric Phase
We give a closed-form solution of von Neumann entropy as a function of
geometric phase modulated by visibility and average distinguishability in
Hilbert spaces of two and three dimensions. We show that the same type of
dependence also exists in higher dimensions. We also outline a method for
measuring both the entropy and the phase experimentally using a simple
Mach-Zehnder type interferometer which explains physically why the two concepts
are related.Comment: 19 pages, 7 figure
A relativistic model of the -dimensional singular oscillator
Exactly solvable -dimensional model of the quantum isotropic singular
oscillator in the relativistic configurational -space is proposed. It
is shown that through the simple substitutions the finite-difference equation
for the -dimensional singular oscillator can be reduced to the similar
finite-difference equation for the relativistic isotropic three-dimensional
singular oscillator. We have found the radial wavefunctions and energy spectrum
of the problem and constructed a dynamical symmetry algebra.Comment: 8 pages, accepted for publication in J. Phys.
The Relativistic Linear Singular Oscillator
Exactly-solvable model of the linear singular oscillator in the relativistic
configurational space is considered. We have found wavefunctions and energy
spectrum for the model under study. It is shown that they have correct
non-relativistic limits.Comment: 14 pages, 12 figures in eps format, IOP style LaTeX file (revised
taking into account referees suggestions
Subthreshold and near-threshold kaon and antikaon production in proton-nucleus reactions
The differential production cross sections of K^+ and K^- mesons have been
measured at the ITEP proton synchrotron in p+Be, p+Cu collisions under lab
angle of 10.5^0, respectively, at 1.7 and 2.25, 2.4 GeV beam energies. A
detailed comparison of these data with the results of calculations within an
appropriate folding model for incoherent primary proton-nucleon, secondary
pion-nucleon kaon and antikaon production processes and processes associated
with the creation of antikaons via the decay of intermediate phi mesons is
given. We show that the strangeness exchange process YN->NNK^- gives a small
contribution to the antikaon yield in the kinematics of the performed
experiment. We argue that in the case when antikaon production processes are
dominated by the channels with KK^- in the final state, the cross sections of
the corresponding reactions are weakly influenced by the in-medium kaon and
antikaon mean fields.Comment: 24 pages. accepted for publication at J.Phys.
Application of stem cells in guided bone regeneration
Modern medicine allows us to study and develop materials and methods of restorative treatment that would be based on the immunological mechanisms of bone repair. One of the promising directions in guided bone regeneration is the use of mesenchymal stem cells. Interest in MSCs is associated with their ability to regulate the inflammatory process, and directly participate in the formation of new bone structures, thereby providing a physiological repair process. The effector impact of MSCs on the inflammatory process due to their ability to form a specific microenvironment. Low expression of MHC-II and CD80/CD86, the production of PGE2 and NO determines their low immunoconflict, and the production of TGF-b1, IDO and IL-10 has an immunomodulating effect. The ability of MSCs to differentiate into an osteogenic phenotype is accompanied with the synthesis of ALP, BSP and, subsequently, Gla-protein and OPN determine the synthesis of the extracellular matrix and its subsequent mineralization. This process is provided by the action of Runx2, which activates the differentiation of MSCs along the osteogenic pathway. These effects of MSCs were taken as the basis for the development of a new method for the treatment of bone atrophy. To accomplish the task set, a model of bone tissue atrophy and a drug containing MSCs was developed, and an experimental study was conducted to evaluate the effectiveness of the developed methodology. As the main criteria, data from clinical and laboratory studies were taken. Visual changes in the studied area were taken into account, compared with a similar area in the developed model of atrophy, the parameters of the complete blood count (CBC) were evaluated. The performed study allows us to determine the developed treatment method as capable of fully recreating the conditions of bone repair processes, taking into account the optimization of the body’s immune reactions and repair processes, without additional external influence, to obtain predictable and controllable results
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