Endothelial cells (ECs) line the blood vessels and lymphatic vessels, as well as heart chambers, forming the border between the tissues, on the one hand, and blood or lymph, on the other. Such a ...strategic position of the endothelium determines its most important functional role in the regulation of vascular tone, hemostasis, and inflammatory processes. The damaged endothelium can be both a cause and a consequence of many diseases. The state of the endothelium is indicated by the phenotype of these cells, represented mainly by (trans)membrane markers (surface antigens). This review defines endothelial markers, provides a list of them, and considers the mechanisms of their expression and the role of the endothelium in certain pathological conditions.
Two prominent magnetoelectrics MnWO4 and CuO possess low-temperature commensurate paraelectric magnetically ordered phase. Here using Monte Carlo simulations we show that the walls between the ...domains of this phase are ferroelectric with the same electric polarization direction and value as those in the magnetoelectric phases of these compounds. We also suggest that experimental observation of electric polarization of domain walls in MnWO4 should help to determine the macroscopic interactions responsible for its magnetoelectric properties.
—Numerical modelling was done with the aim to evaluate the efficiency of applying pseudo-random sequences of current pulses (pseudo-noise signals, PNS) in marine time-domain electromagnetic sounding ...(transient electromagnetic sounding (TEM)) systems with a dipole-dipole array, and to develop specialized methods for processing/interpretation of data obtained under this approach. Based on the analysis of experimental TEM sounding data collected during field studies in the Laptev Sea area, we estimated noise and distortions that obstruct the interpretation of TEM sounding signals. Using the algorithm for the generation of pseudo-random code pulse
M
-sequences and experimental noise records, we simulated PNS sounding signals corresponding to conditions of marine surveying on the Arctic shelf. Processing of noisy synthetic records and reconstruction of the impulse response were based on a convolution equation. Based on the results of the comparison of derived transient responses, reconstructed on the basis of noisy synthetic data in the commonly used stacking and newly proposed PNS modes, it was found that in the PNS mode the relative error of the response estimation increases with time much slower than in the stacking mode and remains within an acceptable value range (up to several percent) until later periods (the curve elongation can reach a decade in time). It is demonstrated that the implementation of the PNS mode in marine electromagnetic sounding systems considerably improves the system performance in terms of the signal/noise ratio (SNR) and expands the range of the applicability of electromagnetic sounding in the Arctic shelf setting.
The article presents the results of studies of internal waves in the shelf zone of the Black Sea in the water area near the mouth of the Kodor River, conducted in June 2021. Spatial surveys were ...carried out with the Rio Grande 600 kHz ADCP, which revealed the main characteristics of currents and the presence of internal waves generated by river inflow into the sea. Internal waves were recorded on two transects oriented along the normal to the coastline and extending to depths of 100 m. The observed waves had the features of nonlinear waves, were located on the near-surface thermocline, and had heights of up to 3–6 m. Also, short-period internal waves in the form of a wave train with an apparent period of about 3.5 min were recorded by a thermistor chain in the coastal zone of the sea. The dispersion curves and eigenfunctions of internal waves were calculated by numerically solving the internal wave equation, taking into account the velocity shift in the sea. Theoretical data are compared with experimental data. The significant influence of river inflow on the parameters of the generated internal waves moving with the flow was revealed. The experimentally observed decrease in wave periods and increase in their group and phase velocities were confirmed.
The article deals with the current state of mineral and raw hydrocarbon base of Ukraine. The main promising directions of geological exploration for oil and gas are identified and determined: in ...reef-carbonate complexes, deep-seated petroliferous complexes, crystalline basement, non-anticlinal traps in sandy bodies, non-traditional HC sources.
The amount of publications devoted to the endothelial cells, on the one hand, and neurological diseases, on the other hand, has been growing rapidly in recent years. Nevertheless, the relationship ...between the endothelial monolayer and the cells of the nervous system remains poorly studied. This review presents the available information about endothelial markers, molecular and cellular mechanisms for maintaining the integrity of the endothelial monolayer and the violations in some acute and chronic neuropsychiatric diseases. At the molecular level, the most important pathogenetic link in endothelial dysfunction is an imbalance of Ca
2+
ions, which is associated with redox imbalance in the cells and increased generation of reactive oxygen species. Genetic and epigenetic factors that cause these disorders and their cause-and-effect relationships are considered. Of the genetic diseases, the most studied are monogenic diseases associated with impaired blood-brain barrier integrity: this is a deficiency of protein molecules that ensure glucose transport, structural and functional integrity of tight junctions and the basement membrane of endothelial cells themselves, as well as mutations in pericytes and smooth muscle cells. Mutations that increase the risk of developing known neurodegenerative diseases, but are also the cause of cerebrovascular pathology, are less studied. The small vessel diseases constitute a whole group of primarily epigenetically caused diseases, the clinical consequence of which is often vascular dementia. Special attention is paid to one of the least studied problems—the pathogenesis of toxicological diseases that occur at different times after acute and chronic organophosphate poisoning. Microangiopathies caused by damage to the endothelium in the central and peripheral nervous systems can be the main cause for the development of delayed effects in organophosphate poisoning. In the absence of effective therapies for neurodegenerative diseases, more and more evidence is emerging about the positive impact of the nutritional structure and healthy lifestyle on the state of blood vessels and the risk of developing these diseases.
The development of high-tech industries stimulates the growth of requirements to metal structures and a complex of their main and special properties. The use of pulsed electrical discharges, plasma ...currents, pulsed electromagnetic fields, and their combined effects to improve the mechanical characteristics of metals and alloys is relevant in connec-tion with the need in replacing traditional energy-intensive technologies of structural materials with more advanced ones. The use of pulsed barrier discharge (PBD) in metal treatment, which generates a low-temperature plasma on the surface of the metal being treated, is a new approach to optimize the mechanical properties of metal materials, which is based on electrophysical processes. In the work, strengthening of structural 25KhGNMT steel as a result of the action of PBD on its surface was studied. The treatment of steel by PBD took place in a discharge device at a voltage incre-ment rate of ≈3•1011V/s. The influence of the duration of PBD treatment on the value of Vickers hardness (HV) of the test samples was studied. The study of the structure of 25KhGNMT steel was carried out by the method of transmission electron microscopy in order to determine its changes as a result of the action of PBD. It was established that HV val-ues after PBD treatment increase from 420 to 500 kg/mm2, which is accompanied by microstructure dispersion, which positively affects the mechanical characteristics of 25KhGNMT steel. References 14, figure 5, table 1.
The formation of secondary structures in nicotrated layers on surfaces of complex-alloy heatresistant 25Kh3M3NBTsA and 30KhN2MFA structural steels under the effect of sliding friction with resource ...lubrication has been studied using metallography, X-ray diffraction, X-ray photoelectron spectroscopy, and thermodynamic modeling. It has been found that, under friction, the nicotrated layer on the steels oxidizes to produce iron oxides, which is substantially less pronounced for 25Kh3M3NBTsA steel than for 30KhN2MFA steel. It has been shown using thermodynamic modeling that, under equilibrium conditions, the heating of both steels to a temperature of ~300°C leads to the formation of an internal-oxidation layer, which consists of FeO with MoO
2
, Cr
2
O
3
, and carbon impurities, a Fe
3
O
4
interlayer with MoO
2
and Cr
2
O
3
impurities, and a top layer of Fe
2
O
3
with Cr
2
O
3
impurity. The heating of steels to a temperature of ~700°C leads to the formation of an internal-oxidation layer, which consists of FeO with MoO
2
and carbon impurities, a Fe
3
O
4
interlayer with MoO
2
impurity, and a top layer of Cr
2
O
3
with Fe
2
MnO
4
and SiO
2
impurities.
The results of studies of internal waves in the shelf zone of the Black Sea in the water area near the mouth of the Kodor River, conducted in June 2021, are presented. Spatial surveys were carried ...out with ADCP “Rio Grande 600 kHz”, which revealed the main characteristics of currents and the presence of internal waves generated by the river inflow in to the sea. Internal waves were recorded in two sections oriented along the normal to the coastline and extending to depths of 100 m. The observed waves had the features of nonlinear waves, were located on the near-surface thermocline, and had a height of up to 3–6 m. Also short-period internal waves in the form of a train of waves with an apparent period of about 3.5 min were recorded by a chain of thermistors in the coastal zone of the sea. The dispersion curves and eigenfunctions of internal waves were calculated by numerically solving the equation of internal waves, taking into account the velocity shift in the sea. Theoretical data are compared with experimental ones. A significant influence of the river inflow on the parameters of the generated internal waves moving with the flow was revealed. The experimentally observed decrease in wave periods and an increase in their group and phase velocities were confirmed.
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