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We have experimentally studied the influence of the local ionosphere, namely the ionospheric Alfvén resonator (IAR) and the lower ionospheric resonator at altitudes 80–300 km (sub-IAR) on the amplitude and polarization of the first Schumann resonance. The study is based on spectral analysis of data from simultaneous monitoring of ULF magnetic noise components at a meridional chain of stations: high-latitude stations Barentsburg and Lovozero, mid-latitude observatory NNGU NIRFI (NL, Nizhny Novgorod Region), a low-latitude station in Israel. We have also used monitoring data from the Borok and Crete observatories. At the stations in dark conditions, significant variations were found in the spectrum of the polarization parameter ε at the frequency of the first Schumann resonance (SR). Moreover, these variations had different character at different observatories. Analysis of the daily dynamics of the parameter ε has shown that these variations are associated with the influence of local sub-IAR having different optical thickness and quality factor at these observatories. The influence of sub-IAR on polarization in the SR band was found to depend on the ratio of the boundary frequency fb (the frequency that separates the negative and positive polarization of ULF magnetic noise) to the frequency of the first SR. The IAR influence on the polarization and amplitude of magnetic fields in the frequency band of the first Schumann resonance was discovered only at the NL and Lovozero stations: a high-quality Alfvén resonator in the ionosphere above the NL station could cause the SR frequency band to change and its central frequency to shift. Analysis of low-frequency data from the observatories separated by distances of 400 km has revealed that the influence of local ionospheric resonators can lead to a difference in the amplitude characteristics of the first SR even at such distances. It has also been shown that the influence of the IAR and sub-IAR resonators on the azimuthal angle of the magnetic field vector in the frequency band of the first SR is less noticeable and can generate variations in this parameter by 10°–20°. Numerical calculations performed for the spherical waveguide model made it possible to adequately interpret the features of the daily dynamics of the parameter ε in the frequency range of the first SR.

Amorphous films of hydrogenated silicon carbide SiCx:H and carbonitride SiCxNy:H have been synthesized in an RF inductively coupled plasma reactor using hexamethyldisilane vapor and additional argon and/or nitrogen gases. The deposition process was carried out at temperatures of 50–400°C and plasma powers of 100–400 W. The dependences of the growth rate, chemical composition and structure of films, light transmittance, refractive index, and optical band gap on synthesis conditions have been obtained. An in situ study of the gas phase composition was performed using optical emission spectroscopy. [ABSTRACT FROM AUTHOR]

Amorphous transparent SiCx:H and SiCxNy:H films are prepared at a temperature of 200 °C and a discharge power of 200 W in an inductively coupled RF plasma reactor using hexamethyldisilane vapors and additional argon and/or nitrogen gases. The influence of N2 flow rate on the morphology, chemical structure, elemental composition, transmittance, refractive index, contact angle, and film deposition rate is studied. Plasma components are determined by optical emission spectroscopy. It is shown by HRTEM and EDS mapping methods that the annealed Cu/SiCx:H/Si(100) sample has distinct substrate/film and film/copper layer interfaces, no Cu diffusion occurs, and that the SiCx:H the film can be considered as a promising diffusion barrier layer. Stability of the films during storage under ambient conditions is studied. The tendency of SiCxNy:H films to oxidize is revealed by EDS, IR spectroscopy, and XPS. [ABSTRACT FROM AUTHOR]

Short-chain fatty acids (which include acetic, propionic, and butyric acids) are metabolites of microbiota that can have diverse physiological effects both in the intestine and outside it, including in the central nervous system. The aim of our work was to study the effect of sodium acetate, propionate, and butyrate on the activity of large conductance Ca2+-activated K+ channels and calcium oscillations in the culture of rat pituitary GH3 cells. It was demonstrated that the studied fatty acids cause a dose-dependent increase in the amplitude of the integral outward potassium currents; these effects are prevented by tetraethylammonium, which indicates the involvement of large conductance Ca2+-activated K+ channels in the effects of fatty acids. Indeed, fatty acids increased open probability of single channels without a change in the amplitude and mean channel open time (dwell time). In addition, they led to a significant decrease in the amplitude and frequency of Ca2+ oscillations in GH3 cells. An increase in potassium conductance and a decrease in the level of intracellular Ca2+ under the effect of short-chain fatty acids can mediate their effects in different excitable structures, such as a decrease in the contractility of intestinal and vascular smooth muscle cells, hyperpolarization of neurons, and regulation of the release of hormones and neurotransmitters. [ABSTRACT FROM AUTHOR]