42 research outputs found

    Comparative Analysis of Verbal Evaluation of Illusory Segments in Children and Adults

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    A comparative study of the strength of the Ponzo and M&uuml;ller-Lyer illusions in preschool children, primary school children and adults was performed. Significant differences in the strength of the Ponzo and M&uuml;ller-Lyer illusions were revealed between groups of children and adults. The results obtained indicate a higher degree of intensity of illusion in children. Meanwhile, no significant differences were found between the groups of primary school and preschool children. For the first time, the magnitude of the illusory effect in children with different levels of maturity of visual perception was compared. When comparing data on the level of maturity of visual perception using the M.M. Bezrukih methodic, we found significant differences in the strength of the Ponzo illusion between groups of children with high and low levels of maturity of perceptual constancy. The results suggest the magnitude of the Ponzo illusion is associated with the maturity level of the constancy of visual perception. Such a connection was not found for the M&uuml;ller-Lyer illusion, which may indicate differences in the mechanisms of formation of the visual illusions under study.</p

    Development of Materials Based on the NiAlCrMoCo System Reinforced with ZrO<sub>2</sub> Nanoparticles

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    This paper describes thermodynamic modeling of the NiAl–CrMoCo system with the calculation of the equilibrium composition and thermodynamic parameters of the system. NiAl-Cr-Mo-Co alloy samples of equiatomic composition, including those with a small addition of zirconium oxide nanoparticles, were obtained by spark plasma sintering of mechanically alloyed powders. It was found that the material had a two-phase structure with wedge-shaped regions enriched in cobalt and molybdenum with a gradient distribution. In addition, in the regions enriched with (Cr, Mo) phase, a lamellar σ phase was found. Fractographic analysis showed a positive effect of the fine-grained wedge-shaped regions on the damping of crack propagation. The alloy with the addition of zirconium oxide nanoparticles had a bending strength and an elastic modulus of 611 MPa and 295 GPa at 25 °C, and 604 MPa and 260 GPa at 750 °C, respectively, when tested in vacuum

    Development of Materials Based on the NiAlCrMoCo System Reinforced with ZrO2 Nanoparticles

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    This paper describes thermodynamic modeling of the NiAl&ndash;CrMoCo system with the calculation of the equilibrium composition and thermodynamic parameters of the system. NiAl-Cr-Mo-Co alloy samples of equiatomic composition, including those with a small addition of zirconium oxide nanoparticles, were obtained by spark plasma sintering of mechanically alloyed powders. It was found that the material had a two-phase structure with wedge-shaped regions enriched in cobalt and molybdenum with a gradient distribution. In addition, in the regions enriched with (Cr, Mo) phase, a lamellar &sigma; phase was found. Fractographic analysis showed a positive effect of the fine-grained wedge-shaped regions on the damping of crack propagation. The alloy with the addition of zirconium oxide nanoparticles had a bending strength and an elastic modulus of 611 MPa and 295 GPa at 25 &deg;C, and 604 MPa and 260 GPa at 750 &deg;C, respectively, when tested in vacuum

    Preparation and Study of Composite Materials of the NiAl-Cr-Mo-Nanoparticles (ZrO2, MgAl2O4) System

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    Materials based on the NiAl-Cr-Mo system with zirconium oxide or aluminum-magnesium spinel nanoparticle small additions were obtained by spark plasma sintering. Thermodynamic modeling was carried out to predict the phase formation in the NiAl-Cr-Mo system and its change depending on temperature, considering the presence of a small amount of carbon in the system. The phase composition and microstructure of materials were studied. NiAl (B2) and CrMo phases were found in the sintered samples. Bending strength measurements at different temperatures shows that nanoparticles of insoluble additives lead to an increase in bending strength, especially at high temperatures. A fractographic analysis of the sample&rsquo;s fractures shows their hybrid nature and intercrystalline fracture, which is confirmed by the clearly visible matrix grains similar to cleavage. The maximum strength at 700 &deg;C (475 MPa) was found for material with the addition of 0.1 wt.% zirconium oxide nanoparticles. In the study of internal friction, typical peaks of a nickel-aluminum alloy were found in the temperature ranges of 150&ndash;200 &deg;C and 350&ndash;400 &deg;C

    The Influence of HCl Concentration on the Rate of the Hydrolysis–Condensation Reaction of Phenyltrichlorosilane and the Yield of (Tetrahydroxy)(Tetraphenyl)Cyclotetrasiloxanes, Synthesis of All Its Geometrical Isomers and Thermal Self-Condensation of Them under “Pseudo”-Equilibrium Conditions

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    The rate of hydrolysis–condensation reaction of phenyltrichlorosilane in water-acetone solutions and the product yields were shown to significantly depend on the concentration of HCl (CHCl) in the solutions. The main product of the reaction was all-cis-(tetrahydroxy)(tetraphenyl)cyclotetrasiloxane. This was different from the earlier published results of analogous reactions of m-tolylSiCl3, m-ClPhSiCl3, and α-naphtylSiCl, in which some products of other types were formed. For example, trans-1,1,3,3-tetrahydroxy-1,3-di-α-naphtyldisiloxane was obtained in the case of α-naphtylSiCl3. All-cis-(tetrahydroxy)(tetraphenyl)cyclotetrasiloxane was treated in acetone with HCl to give the other three geometric isomers (cis-cis-trans-, cis-trans-, and all-trans-). The thermal self-condensation of these four isomers under “pseudo”-equilibrium conditions (under atmospheric pressure) was investigated in different solvents, in quartz or molybdenum glass flasks. The compositions of the products were monitored by APCI-MS and 29Si NMR spectroscopy. It was shown that all-cis- and cis-cis-trans-isomers in toluene or anisole mostly gave the cage-like Ph-T8,10,12,14 and uncompleted cage-like Ph-T10,12OSi(HO)Ph compounds. In contrast to these two isomers, the cis-trans–isomer in toluene mainly formed dimers with the loss of one or two molecules of water. However, in acetonitrile, significant amounts of Ph-T10,12 and Ph-T10,12OSi(HO)Ph species were formed along with the dimers. All-trans-isomer did not enter into the reaction at all

    A Study of the Influence of the HCl Concentration on the Composition and Structure of (Hydroxy)Arylsiloxanes from the Hydrolysis–Condensation Reaction of Aryltrichlorosilanes

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    The hydrolysis&ndash;condensation reactions of m-tolyl, m-chlorophenyl, and &alpha;-naphtyl-trichlorsilanes, (1, 2, and 3, respectively) in water-acetone solutions were examined for how they were influenced by the change in the concentration of HCl (CHCl). The composition of the products was monitored by 29Si NMR spectroscopy and atmospheric pressure chemical ionization mass spectrometry (APCI-MS). The acidity of the medium was shown to affect the yields of the products, and so, what products were formed. For 3, e.g., APCI-MS showed peaks of &alpha;-naphtyl-T8 and &alpha;-naphtyl-T10 as the most abundant in the spectra taken after 48 and 240 h for the reaction conducted at CHCl = 0.037 mol L&minus;1. Unlike this, at CHCl = 0.15 mol L&minus;1, those peaks were of [&alpha;-naphtyl(HO)2SiO]2(&alpha;-naphtyl)(HO)Si and/or [&alpha;-naphtyl(HO)Si]3, [&alpha;-naphtyl(HO)Si]4,5, and &alpha;-naphtyl-T8 after 192 h. However, at both CHCl values, the main product (and an intermediate) after 24 h was trans-1,1,3,3-tetrahydroxy-1,3-di-&alpha;-naphtyldisiloxane. It was isolated and its structure established by 1H-, 29Si-NMR, and X-ray powder diffraction

    Compartmentalization of superoxide dismutase 1 (SOD1G93A) aggregates determines their toxicity

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    Neurodegenerative diseases constitute a class of illnesses marked by pathological protein aggregation in the brains of affected individuals. Although these disorders are invariably characterized by the degeneration of highly specific subpopulations of neurons, protein aggregation occurs in all cells, which indicates that toxicity arises only in particular cell biological contexts. Aggregation-associated disorders are unified by a common cell biological feature: the deposition of the culprit proteins in inclusion bodies. The precise function of these inclusions remains unclear. The starting point for uncovering the origins of disease pathology must therefore be a thorough understanding of the general cell biological function of inclusions and their potential role in modulating the consequences of aggregation. Here, we show that in human cells certain aggregate inclusions are active compartments. We find that toxic aggregates localize to one of these compartments, the juxtanuclear quality control compartment (JUNQ), and interfere with its quality control function. The accumulation of SOD1G93A aggregates sequesters Hsp70, preventing the delivery of misfolded proteins to the proteasome. Preventing the accumulation of SOD1G93A in the JUNQ by enhancing its sequestration in an insoluble inclusion reduces the harmful effects of aggregation on cell viability
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