The mechanoelectrical feedback in the heart is based on the work of mechanically gated (MGCs) and mechanosensitive (MSCs) channels. Since microgravity alters the heart’s morphological and ...physiological properties, we hypothesized that the expression of both MGCs and MSCs would be affected. We employed RNA transcriptome sequencing to investigate changes in the gene transcript levels of MGCs and MSCs in isolated rat ventricular cardiomyocytes under control conditions and in a simulated microgravity environment. For the first time, our findings demonstrated that simulated microgravity induces alterations in the gene transcript levels of specific MGCs, such as TRPM7, TRPV2, TRPP1, TRPP2, Piezo1, TMEM63A, TMEM36B, and known MSCs, including K
2P
2.1, K
2P
3.1, Kir6.1, Kir6.2, Na
V
1.5, Ca
V
1.2, K
V
7.1. However, other voltage-gated channels and channels lacking a voltage sensor remained unaffected. These findings suggest that the altered expression of MGCs and MSCs could lead to changes in the net currents across the membrane, ultimately impacting the heart’s function.
A number of genetic or drug-induced pathophysiological disorders, particularly neurodegenerative diseases, have been reported to correlate with catalytic impairments of NADH:ubiquinone oxidoreductase ...(mitochondrial complex I). The vast majority of the data on catalytic properties of this energy-transducing enzyme have been accumulated from studies on bovine heart complex I preparations of different degrees of resolution, whereas almost nothing is known about the functional activities of the enzyme in neuronal tissues. Here a procedure for preparation of coupled inside-out submitochondrial particles from brain is described and their NADH oxidase activity is characterized. The basic characteristics of brain complex I, particularly the parameters of A/D-transition are found to be essentially the same as those previously reported for heart enzyme. The results show that coupled submitochondrial particles prepared from either heart or brain can equally be used as a model system for in vitro studies aimed to delineate neurodegenerative-associated defects of complex I.
The results of the study of the phase and elemental composition, the state of the defective substructure, the mechanical and tribological properties of the powder coating of the Ni-Cr-B-Si system ...formed on A356Gr1 steel using a combined method, which includes plasma spraying and the subsequent irradiation with an intense pulsed electron beam in the melting mode of the surface layer, are presented. It is shown that the combined treatment is accompanied by formation of a surface layer with a thickness up to 1500 microns, the microhardness and the wear resistance of which manifold exceed the corresponding characteristics of the reference steel.
Surface nanostructuring of Ti-6Al-4V titanium alloy samples in the process of electron-beam treatment and ultrasonic impact treatment have been studied using the methods of transmission electron ...microscopy and X-ray structural analysis. The effect of nanostructured surface layer of the Ti-6Al-4V titanium alloy on elastic recovery during scratch test, and, therefore, their wear resistance was demonstrated.
This paper is devoted to obtaining the multimaterials using the electron-beam wire-feed additive manufacturing technology. The sample of titanium alloy Ti-6Al-4V and stainless steel 321 composition ...was obtained. It was found that steel and Ti-alloy form a transitional intermediate layer between themselves. The Ti-alloy layer does not undergo major changes, while the layer of stainless steel undergoes significant cracking.
In the present study, a microstructural investigation of wire-feed EBAM-manufactured nickel-based and titanium-based alloys were conducted by producing single wall sample with 16 and 19 vertical ...layers, respectively. It was shown that in obtained material microstructural and elemental gradient presents. The results of the research show that dendrites and grains grow epitaxial in the direction of temperature gradient. Non-directional dissipation of heat on the edge of the sample leads to formation of equiaxed structure. Chosen parameters allow to produce low-defective samples by EBAM technology.
The results of the investigation of evolution structural phase states of the surface layer «film (Ti)/substrate (SiC-ceramics)» system subjected to processing with an intense pulsed electron beam are ...presented (Ti film 0.5 μm thick was deposited on the surface SiC ceramic). Samples of SiC ceramics obtained by SPS-sintering were used. Irradiation with an intense pulsed electron beam of submillisecond duration was carried out at the «SOLO» device under the condition: energy density of the electron beam of 15 J/cm2, pulse duration of 200 μs, quantity of pulses - 20 and 30. The X-ray diffraction analysis of the treated electron beam «Ti/SiC» system showed that under the specified irradiation regime the phase composition formed in the surface layer and the volume fraction of the phases depend on the quantity of irradiation pulses. At 20 pulses, following phase composition of the surface layer was formed: SiC - 18.5 %, TiC - 36.6 %, Ti5Si3 - 44.9 %; at 30 pulses, a phase relationship: SiC - 81.6 %, TiC - 12.7 %, Si - 0.5 %, C - 5.2 %. Scanning and transmission electron microscopy revealed, that irrespective of the quantity of pulses of the electron beam, takes place the formation of a surface layer with a globular structure, formed as a result of melting of the titanium film, which contains a droplet fraction. The particles of the drop fraction had a submicro-nanocrystalline structure and were enriched mainly by titanium, silicon and carbon atoms. It was established that electron beam treatment with 30 pulses leads to formation of round-shaped regions on the surface of irradiation, the microhardness of which varies from 55 GPa to 96 GPa, which is several times the microhardness of the initial SiC ceramic (36 GPa). It was suggested that these regions were formed as a result of electron beam treatment of the surface layer, which contains a drop fraction.
In view of the possible effect of contamination of a plasma by metal particles on the operation of a number of facilities or on the detection of the motion of liners by Doppler methods, a particular ...attention has been recently focused on the problem of the ejection of particles from the shock-loaded free surface of a sample or on the “dusting” problem. Most information concerns the dusting source associated with the roughness of the surface, manufacturing technology, and the defectiveness and aging of a material. Factors affecting this process such as the profile and amplitude of the pressure on the front of the shock wave arriving at the free surface of the sample, the presence of the gas in front of the free surface, and the pressure in this gas are less studied.
The structure of samples of the C27400 copper alloy coatings on the AA5056 aluminum alloy surface, produced by friction stir processing of a rolled sheet package is studied. The regularities of the ...structure formation at deformation-initiated mixing of Al–(Cu, Zn) system components are elucidated. Intensive diffusion and mechanical mixing of the Al–(Cu, Zn) system components is revealed, resulting in the formation of a complex structure of the stir zone on the macrolevel. It is established that during the formation of the structural-phase composition of the coating, the solid aluminum solutions are formed in copper by zinc extrusion from the solid solution together with complex solid solutions and intermetallic phases by zinc diffusion into the aluminum lattice.
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