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 NN-dimensional singular oscillator

Exactly solvable $N$-dimensional model of the quantum isotropic singular oscillator in the relativistic configurational $\vec r_N$-space is proposed. It is shown that through the simple substitutions the finite-difference equation for the $N$-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