A clinical case of demyelinating lesions of the brain: Central pontine myelinolysis

In the scientific review a rare demielinizirute disease of the brain - central pontine myelinolysis is presented. Prior to the introduction of the technique of visualization, diagnosis of the disease was through autopsy. Clinical case, which describes the variety neurological and somatic symptoms, was presented. The attention is focused on the importance of an integrated approach to diagnosis and management of the patient with the disease.В научном обзоре представлено редкое демиелинизрующее заболевание головного мозга: центральный потинный миелинолиз. До внедрения визуализирующих методов исследования оно диагностировалось только при аутопсии. Приведен клинический случай, описано многообразие неврологической и соматической симптоматики. Акцентировано внимание на значимость комплексного подхода к диагностике и ведения пациента с редким заболеванием

Pairs of electronic states supporting the wave process of martensite crystal growth

A model dispersion law for electrons (in the tight-binding approximation with allowance for the first ε1 and second ε2 nearest neighbors) is used for body-centered cubic (b.c.c.) crystals to analyze the shapes of the S-surfaces that separate the pairs of electronic states (ES) supporting of the controlling wave process in the non-equilibrium conditions. For b.c.c. and face-centered cubic crystals, the following parameters are calculated: the density of electronic states and portion ζ of ES-pairs localized in the energy interval Δ ≈ 0.2 eV in the proximity of Fermi level μ for different values ε2. The value μ is choosed close to the energy εp of the peak of density of electronic states. The results testify that the wave model of martensite crystal growth supporting non-equilibrium electrons is adequate. © 2006 Elsevier B.V. All rights reserved

Pairs of inversely occupied electronic states in the energy range best suited to wave generation

For a model electronic spectrum of a bcc crystal, characteristic s-surfaces are found that separate, in the quasi-momentum space, pairs of electronic states potentially active in the generation of elastic waves at the stage of growth of a martensite crystal. Numerical estimation of the fraction of active electronic states (R eff/R) is performed for the energy range Δ = 0.2 eV near the Fermi level. The ratio R eff/R is calculated as a function of the parameter ratio for the interaction between the nearest and the second neighbors for both bcc and fcc lattices. © 2005 Springer Science+Business Media, Inc

Conditions required for nonequilibrium electrons to generate elastic waves in metals with a cubic lattice

A model dispersion law for electrons (in the tight-binding approximation with allowance for the first and second nearest neighbors) is used for bcc crystals to analyze the shapes of the s surfaces that separate the pairs of electronic states (in the quasi-momentum space) that are potentially active for the generation (amplification) of atomic-displacement waves that control the growth of a martensite crystal under conditions of high chemical-potential gradients. For bcc and fee crystals, the following parameters are calculated: the densities of states and the fractions of the pairs of electronic states (which are potentially active for phonon generation) depending on the Fermi level μ with respect to the energy εp of a peak in the density of states at a fixed energy range |μ - ε| ≤ △ for △ = 0.2 eV. The results obtained are discussed, and it is shown that the effect of lattice distortions in the interphase region on the threshold conditions of phonon generation must be taken into account. Copyright © 2005 by Pleiades Publishing, Inc

Ab initio analysis of the effect of strain on the density of non-equilibrium electronic states and their role in the wave model of martensitic transformations

In the wave model of martensitic transformations, the influence of the tensile strain on the creation of non-equilibrium electrons is crucial for the principle of wave amplification by stimulated emission of phonons from an inverted electronic population. By consideration of the strain-effect on the electronic energy spectrum it is shown that - for certain interval of finite strain - the density of active electronic non-equilibrium states in a strained lattice can satisfy the conditions for a phonon-maser effect. © 2007 Elsevier B.V. All rights reserved

Effect of uniaxial deformation on the number of pairs of inversely populated electronic states

Simple electronic spectra are considered in the tight-binding approximation for the case of uniform uniaxial deformation. It is shown that there is a range of deformations (considerably exceeding a threshold one) in which conditions for the generation of phonons by nonequilibrium electrons are satisfied. Moreover, in this range an increase in the deformation is accompanied by an increase in the number of pairs of potentially active electronic states. The effect is pronounced more strongly in the case of tensile deformation. The results obtained are important for the development of the theory of reconstructive martensitic transformations. © 2008 Pleiades Publishing, Ltd

Critical Diameters of Grains or Individual Particles for the Start of a Martensitic Reaction from the Positions of Dynamic Theory

In the case of spontaneous (under cooling) γ–α martensitic transition in iron alloys, the formation of a martensitic crystal is determined by a wave controlling process and occurs at a supersonic velocity as compared to longitudinal waves. The initiation of three-dimensional threshold deformation is associated with the coordinated action of relatively long (Formula presented.)-wave and relatively short s-waves. The (Formula presented.)-waves appearing during the formation of an initial excited state (IES) are responsible for the description of habit planes. This approach is efficient both in the description of twinned crystals and in the limit case of a degenerate twin structure comparable to the formation of dislocation crystals at initial γ-phase grain sizes exceeding the critical values of Dc. In the case of a nanocrystalline state, the variants of grain transformation as a whole are observed and provisionally classified as an accommodative martensitic transition (AMT). The critical size Dac for AMT is less than Dc. In dynamic theory, Dac can be associated with the spatial IES scaling process compared with the propagation of cylindrical and spherical waves for a relative change in volume. In such a transformation scenario, Dac and the critical size for the transition of small free particles are determined by the threshold deformation value. © 2022, Pleiades Publishing, Ltd

A Cryston Model for the Formation of Typical Rolling Texture Components in a Metal with a Cubic Lattice

In the process of plastic deformation by rolling, polycrystalline specimens with an initially chaotic orientation for the crystal lattices of grains are usually textured, i.e., there occur several selected grain lattice orientations, in which well-defined planes make up the smallest angles with the rolling plane. When interpreting the observed typical structures for crystals with cubic latticed, it has been shown that the comprehensive description of textures is attained within the framework of cryston approach. The essence of cryston approach associated with the contact interaction of dislocations during the intersection of sliding planes is briefly described in the section devoted to the main textural component in crystals with a face-centered cubic lattice. Afterwards, some information about the typical textures in crystals with a body-centered cubic lattice is given, and the cryston “composition” reflecting the partial contribution of dislocations belonging to interacting sliding systems is presented for every texture. When discussing the results, it is shown that there are some grounds to consider the formation of observed textures as the trend of an open nonequilibrium system to relax to an equilibrium state in the shortest possible way in time. This conclusion is equivalent to the Ziegler’s principle of maximum entropy production for open systems far from equilibrium. © 2022, Pleiades Publishing, Ltd

REGULATORY-ADAPTIVE POSSIBILITIES OF THE ORGANISM IN DIFFERENT FORMS OF CHRONIC PERIODONTITIS IN ACUTE

48 patients with various forms of chronic periodontitis before and after treatment were carried out sample cardiorespiratory synchronism, the index was calculated regulatory-adaptive status, as it was determined by the regulatory-adaptive capabilities of the organism. If any form of periodontal disease on the human body affects the pain factor. After his removal by the treatment of periodontitis regulatory and adaptive capacity increased. Thus, the regulatory and adaptive capacity of the body can serve as an indicator of the effectiveness of the treatment of periodontitis