Tomsk National Research University

Tomsk, Russia

Tomsk National Research University

Tomsk, Russia
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Ayzenshtat G.I.,Tomsk National Research University | Yushchenko A.Y.,Research Institute of Semiconductor Devices
Instruments and Experimental Techniques | Year: 2015

It was determined that the forward loss resistance as a function of the radius of the active region of typical microwave p-i-n diodes depends on the ratio of the square of the ambipolar-diffusion length to the square of the radius of the diode active region. Based on this regularity, a method was developed that provides simple determination of the ambipolar-diffusion length and the carrier lifetime. © 2015, Pleiades Publishing, Inc.


Koltsova S.V.,Moscow State University | Tremblay J.,Center Hospitalier Of Luniversite Of Montreal Crchum Technopole Angus | Hamet P.,Center Hospitalier Of Luniversite Of Montreal Crchum Technopole Angus | Orlov S.N.,Moscow State University | Orlov S.N.,Tomsk National Research University
Cell Calcium | Year: 2015

Previously, we reported that Ca2+ depletion increased permeability of the plasma membrane for Na+. This study examined the relative impact of [Na+]i/[K+]i-mediated signaling on transcriptomic changes in cultured vascular smooth muscle cells from rat aorta (VSMC) subjected to Ca2+-depletion by extra-(EGTA) and intracellular (BAPTA-AM) Ca2+ chelators. Na+,K+-ATPase inhibition in K+-free medium during 3h led to elevation of [Na+]i and attenuation of [K+]i by ~7- and 10-fold, whereas Ca2+-depletion resulted in alteration of these parameters by ~3- and 2-fold, respectively. Augmented VSMC permeability for Na+ and elevation of the [Na+]i/[K+]i ratio was triggered by addition to Ca2+-free medium 50μM EGTA and was not affected by 10μM BAPTA-AM. Na+,K+-ATPase inhibition and Ca2+-depletion changed expression of 3677 and 4610 mRNA transcripts, respectively. We found highly significant (p<10-12) positive (R2>0.51) correlation between levels of expression of 2071 transcripts whose expression was affected by both stimuli. Among genes whose expression in Ca2+-depleted cells was augmented by more than 7-fold we noted cyclic AMP-dependent transcription factor Atf3, early growth response protein Egr1 and nuclear receptor subfamily 4, group A member Nr4a1. Dissipation of transmembrane gradients of monovalent cations in high-K+, low-Na+-medium abolished the increments of the [Na+]i/[K+]i ratio as well as the augmented expression of these genes triggered by incubation of VSMC in EGTA containing medium. Thus, our results demonstrate, for the first time, that robust transcriptomic changes triggered by Ca2+-depletion in the presence of extracellular Ca2+-chelators are at least partially mediated by elevation of the [Na+]i/[K+]i ratio and activation of Ca2+i-independent, [Na+]i/[K+]i-mediated mechanism of excitation-transcription coupling. These results shad a new light on analysis of data obtained in cells subjected to long-term exposure to Ca2+ chelators. © 2015 Elsevier Ltd.


Ryl'Tsova I.G.,Belgorod State University | Nestroinaya O.V.,Belgorod State University | Lebedeva O.E.,Belgorod State University | Vorontsova O.A.,Belgorod State University | And 2 more authors.
Russian Journal of Inorganic Chemistry | Year: 2014

Series ol layered double hydroxides (LDHs) of the hydrotalcite family simultaneously containing iron and cobalt cations in the positions of triply charged metal ions of the brucite-like sheets, were prepared by coprecipitation of the components from solution in an oxidative medium. The materials prepared have been characterized by X-ray powder diffraction, temperature-programmed reduction (TPR), and temperature-programmed destruction (TPD); their behavior during dehydration-rehydration cycling was studied. The layered double hydroxides were shown to be reducible when heated in flowing hydrogen. Heating to 600°C induced the reduction of cobalt and iron to doubly charged cations, and at temperatures higher than 600°C the reduction yielded the metals. The thermal destruction products of the LDHs prepared are capable of recovering their layered structure when reacted with aqueous sodium carbonate solutions; however, this capability is reduced as the cobalt content in the sample increases. © 2014 Pleiades Publishing, Ltd.


Vereshchagin V.I.,Tomsk National Research University | Mogilevskaya N.V.,Krasnoyarsk State Economics and Trade Institute | Gorbachev D.V.,KDS Lipetsk
Glass and Ceramics (English translation of Steklo i Keramika) | Year: 2013

The sintering, structure and properties of low-fired porcelain obtained from pastes with marshalite or marshalite with diopside replacing quartz sand are studied. The sintering temperature of porcelain made using the experimental pastes is 100 C lower (1150 C compared with 1260 C for the initial paste). © 2013 Springer Science+Business Media New York.


Litovchenko I.Y.,RAS Institute of Strength Physics and Materials Science | Tyumentsev A.N.,RAS Institute of Strength Physics and Materials Science | Akkuzin S.A.,Tomsk National Research University | Naiden E.P.,Tomsk National Research University | Korznikov A.V.,Russian Academy of Sciences
Physics of Metals and Metallography | Year: 2016

It has been shown that, in metastable austenitic Fe–18Cr–10Ni–Ti steel, under conditions of torsion under pressure, local reversible (forward plus reverse) (γ → α′ → γ) martensitic transformations can occur, which are one of the mechanisms of the formation of nanostructured states. An increase in the rotation rate, which leads to an increase in the deformation temperature, stimulates the reverse (α′ → γ) transformation. The evolution of the structural and phase states is represented as the following sequence: (1) mechanical twinning; (2) nucleation of martensitic plates in the microtwinned structure of the austenite with the formation of two-phase (γ + α′) structures, packet α′ martensite, and structural states with a high curvature of the crystal lattice; (3) reverse (α′ → γ)-transformations; and (4) the fragmentation of nanosized crystals via the formation of a nanotwinned structure in the austenite and of a nanoscale banded structure of the ε martensite in the α′ martensite. © 2016, Pleiades Publishing, Ltd.


Volkov R.S.,Tomsk National Research University | Zhdanova A.O.,Tomsk National Research University | Vysokomornaya O.V.,Tomsk National Research University | Kuznetsov G.V.,Tomsk National Research University | Strizhak P.A.,Tomsk National Research University
Journal of Engineering Physics and Thermophysics | Year: 2014

We have made experimental studies of the processes of deformation of drops (of size up to 6 mm) of three liquids with different physical properties (water, ethanol, kerosene) in motion in a gaseous medium (air) with velocities of up to 5 m/s. The most typical forms of drops have been distinguished, and the cyclic character of their change in traveling in a gaseous medium to distances of up to 1 m has been established. The characteristic "deformation cycles" in the process of motion have been determined, and the time intervals of the form change within each "deformation cycle" have been established. The maximum deviations of drop sizes from the initial ones have been calculated, and the influence of their sizes and velocities on the basic characteristics of the deformation have been determined. © 2014, Springer Science+Business Media New York.


Krainov A.Y.,Tomsk National Research University
Journal of Engineering Physics and Thermophysics | Year: 2015

We have formulated a physicomathematical model of the flame propagation in a combustible gas containing water aerosol based on the thermal-diffusion model of the laminar flame propagation in a gas and taking into account the processes of heat and mass transfer between the phase and liquid drops. Computational-theoretical studies of the influence of water aerosol characteristics on the flame velocity in a lean methane–air mixture have been made. Comparison of the results of calculations with experimental data has shown that there is good agreement between them. Comparison of the efficiency of using water aerosol and inert gas to stop the spread of fire has shown that there exists a limiting size of the dispersed phase above which the efficiency of using water aerosol and inert powders to stop the spread of fire becomes equal. © 2015 Springer Science+Business Media New York

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