Nanostructure Formation in Superior Quality Rails

Using transmission electron microscopy methods the layer by layer analysis of the bulk hardened superior quality rails is carried out and the quantitative parameters of structure, phase state and defect substructure gradients are established. The gradient character of changing of structure-phase states and dislocation substructure along the cross section of rail head is revealed. The oil bulk hardening of superior quality rails is accompanied by the formation of morphologically different structure, being produced according to the shear and diffusion of γ-α transformation. The base structure volume is formed by the diffusion mechanism and is consisted of plate pearlite grains, free ferrite grains and grains of ferrite-carbide mixture. The presence of the bend extinction contours testifying to curvature-torsion of crystal lattice is revealed on electron microscope images. The analysis of far acting internal field stresses created by interfaces of cementite plates of pearlite grains and interfaces of pearlite and ferrite grains is carried out. It is shown that the interface boundaries globular cementite particles-matrix are the possible places of microcracks initiation

Nanostructure Formation in Superior Quality Rails

Using transmission electron microscopy methods the layer by layer analysis of the bulk hardened superior quality rails is carried out and the quantitative parameters of structure, phase state and defect substructure gradients are established. The gradient character of changing of structure-phase states and dislocation substructure along the cross section of rail head is revealed. The oil bulk hardening of superior quality rails is accompanied by the formation of morphologically different structure, being produced according to the shear and diffusion of γ-α transformation. The base structure volume is formed by the diffusion mechanism and is consisted of plate pearlite grains, free ferrite grains and grains of ferrite-carbide mixture. The presence of the bend extinction contours testifying to curvature-torsion of crystal lattice is revealed on electron microscope images. The analysis of far acting internal field stresses created by interfaces of cementite plates of pearlite grains and interfaces of pearlite and ferrite grains is carried out. It is shown that the interface boundaries globular cementite particles-matrix are the possible places of microcracks initiation

The dynamics of Sert, Htr4a, and Bdnf genes expression in the blood of rats under chronic stress exposure

In this article, we discuss the expression levels of Sert, Htr4a, and Bdnf genes in the blood of Wistar rats exposed to the following types of chronic stresses for 270 days: swimming with a load and immobilization, as well as the combination of these two stresses. On day 180 of the experiment, the stresses described above triggered an increase in Sert expression in both females and males of all the groups, except the control group. The immobilization stress induced for 270 days caused an increase in the level of Sert expression in females and reduced it in males. In response to the stresses under study, the expression of Htr4a decreased in males, but not females, on day 270. The expression of Bdnf decreased on day 270 in males after the combined stress and in females subjected to immobilization. Thus, the expression levels of some genes involved in the peripheral transmission of serotonin are greatly influenced by chronic stresses and depend on gender, duration of exposure to stress, and type of stress factors

Photo Controlled Surfaces in Rheology of Liquid Crystals

The modified method for shear viscosity measurements of nematic liquid crystals (NLC) oriented by surfaces is described. The main modification is concerned with usage of photoalignment technique for preparation of mono-domain samples with an orientation controlled by a polarization state of the secondary light irradiation. It provides the azimuthal rotation of a sample at any desirable angle. Thus different geometries of shear flows can be realized after filling the measuring cell with a liquid crystal. The method is experimentally approved at investigation of Poiseuille decay flows of 4-pentyl-4-cyanobiphenyl (5CB) through the channels with a rectangular cross section. The proposed construction of the cell with different surface treatment provides measurements of the three principal viscosities coefficients (Miesowicz' viscosities) with additional usage of electric field. A small amount (less than 0.2 ml) of a liquid crystal needed for measurements and simple measuring procedure makes the method to be useful for rheological studies of newly synthesised liquid crystal materials. Copyright © 2015 Taylor & Francis Group, LLC

Severe rhinovirus bronchiolitis in premature infant with bronchopulmonary dysplasia

Acute bronchiolitis is an inflammatory disease of the lower respiratory tract with a predominant lesion of small bronchi and bronchioles developing in children under 2 years of age. The main etiological factor of bronchiolitis is the respiratory syncytial virus (RSV), the second place in the etiologic structure belongs to rhinovirus, which causes bronchiolitis usually at 6 months age. Severe bronchiolitis is characterized by the need for auxiliary or artificial lung ventilation (ALV). The main risk groups for severe bronchiolitis include premature infants with or without bronchopulmonary dysplasia (BPD), children with hemodynamically significant congenital heart defects. The article presents a clinical observation of rhinovirus bronchiolitis severe course in a preterm infant aged 4,5 months (post-conceptual age-42 weeks) with severe BPD manifesting with an apnea episode followed by the development of severe respiratory failure requiring mechanical ventilation accompanied by sinus tachycardia. The study demonstrates the possibility of acute bronchiolitis severe course in a premature infant with BPD, not only because of RSV infection, but with rhinovirus infection in the first half of life, which should be considered during virus examination. © 2017, Pediatria Ltd. All rights reserved

Severe rhinovirus bronchiolitis in premature infant with bronchopulmonary dysplasia

Acute bronchiolitis is an inflammatory disease of the lower respiratory tract with a predominant lesion of small bronchi and bronchioles developing in children under 2 years of age. The main etiological factor of bronchiolitis is the respiratory syncytial virus (RSV), the second place in the etiologic structure belongs to rhinovirus, which causes bronchiolitis usually at 6 months age. Severe bronchiolitis is characterized by the need for auxiliary or artificial lung ventilation (ALV). The main risk groups for severe bronchiolitis include premature infants with or without bronchopulmonary dysplasia (BPD), children with hemodynamically significant congenital heart defects. The article presents a clinical observation of rhinovirus bronchiolitis severe course in a preterm infant aged 4,5 months (post-conceptual age-42 weeks) with severe BPD manifesting with an apnea episode followed by the development of severe respiratory failure requiring mechanical ventilation accompanied by sinus tachycardia. The study demonstrates the possibility of acute bronchiolitis severe course in a premature infant with BPD, not only because of RSV infection, but with rhinovirus infection in the first half of life, which should be considered during virus examination. © 2017, Pediatria Ltd. All rights reserved