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© 2021 The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature., We have experimented with isolated cardiomyocytes of mollusks Helix. During the whole-cell patch-clamp recordings of K+ currents a considerable decrease in amplitude was observed upon repeated voltage steps at 0.96 Hz. For these experiments, ventricular cells were depolarized to identical + 20 mV from a holding potential of - 50 mV. The observed spontaneous inhibition of outward currents persisted in the presence of 4-aminopyridine, tetraethylammonium chloride or E-4031, the selective class III antiarrhythmic agent that blocks HERG channels. Similar tendency was retained when components of currents sensitive to either 4-AP or TEA were mathematically subtracted. Waveforms of currents sensitive to 1 and 10 micromolar concentration of E-4031 were distinct comprising prevailingly those activated during up to 200 ms pulses. The outward current activated by a voltage ramp at 60 mV x s-1 rate revealed an inward rectification around + 20 mV. This feature closely resembles those of the mammalian cardiac delayed rectifier IKr.

Effects of ibutilide, a class III antiarrhythmic drug, on delayed rectifier potassium currents (IK) in freshly isolated guinea pig ventricular myocytes were studied. Experiments were performed using the whole-cell configuration of patch-clamp technique under blockade of L-type calcium currents (Cav1). Ibutilide at concentrations ranging between 10 nM and 100 µM inhibited IKr in dose-dependent manner with a half maximal effective concentration of 2.03 ± 0.74 µM (n = 5–10). The amplitude of tail currents activated by prepulse to + 20 mV was decreased from 253 ± 52 to 130 ± 25 pA (n = 8, p

The quantum chemical calculations of the energies, electronic structures, and geometries for the products and intermediates of the ipso-nitration of 5,6-dimethyl-substituted 2-oxo- and 2-thioxothieno[2,3-d]pyrimidin-4-ones, as well as 6-methyl-5-nitrothieno[2,3-d]pyrimidin-4-one and 3,6-dimethyl-4-oxo-3,4-dihydrothieno[2,3-d]pyrimidine-5-carboxylic acid formed under the action of a nitrating mixture on 5,6-dimethylthieno[2,3-d]pyrimidin-4-one and 3,5,6-trimethylthieno[2,3-d]pyrimidin-4-one, respectively, were performed in terms of the HF and DFT (B3LYP) approximations in the 3-21G basis set. Taking into account the substituent effects in the pyrimidine cycle, solvents, and prototropic tautomerism, possible reasons for the predominant ipso-substitution of the methyl group at the C(5) atom by the nitro group of the thienopyrimidine system and differences in behavior of 3-unsubstituted and 3-substituted thieno[2,3-d]pyrimidin-4-ones were considered.

The main goal of the present study was to determine the effect of the native vegetation on the successive development of the soil ecosystem at abandoned coal-ash landfills of the Angren coal-fired power plant in Uzbekistan. Two different landfills (one not in use for 3 years, termed newer, and the other not in use for 10 years, termed older) with different degrees of vegetation cover were chosen to assess the time and vegetation effects on soil biota and habitat development. The soil biotic structure, including soil microorganisms and soil free-living nematode communities, was investigated both at open plots and under different native plants at the coal-ash landfill area. The observed soil microorganisms were found to be the most important component of the observed ecosystems. Total abundance, biomass, species, trophic and sexual diversity of soil free-living nematodes, along with fungi and organic-matter content, were found to be correlated with trace metals. The nematode trophic and species abundance and diversity increased from the newer toward the older coal-ash landfills. The sex ratio of the nematode communities was found to be dependent on the environmental conditions of the study area, with the males being the most sensitive nematode group. All applied ecological indices confirmed that open landfill plots distant from plants are the most unfavorable areas for soil biota. In that respect, the native plants Alhagi maurorum Desv. and Tamarix sp. were found to be important environmental components for the natural remediation of a soil ecosystem in the coal-ash landfill area.

Several water-soluble acetylsalicylamino acids and peptides containing neutral and acidic amino acids were synthesized and investigated for anti-inflammatory activity.

Nonlinear refraction, nonlinear absorption and optical limiting in photorefractive crystals Bi12SiO20(BSO) and Bi12GeO20(BGO) at the wavelengths of 1064 and 532 nm were investigated. It was shown that both BSO and BGO crystals possess by positive nonlinear refraction in two investigated spectral ranges (n2BSO=(2.5 ± 0.5)× 10−12 esu, n2BGO=(6.3 ± 1.3)× 10−12 esu at λ equals 1064 nm; n2BSO=(4.4 plusmn; 0.9)× 10−12 esu, n2BGO=(7.4 ± 1.5)× 10−12 esu at λ= 532 nm). The nonlinear absorption was due to three-photon absorption at the wavelength of 1064 nm (β(3ω)BSO=(2.5 ± 0.8)× 10−20cm3W−2, β(3ω)BSO=(4.4 ± 1.3)× 10−20cm3W−2) and two-photon absorption at the wavelength of 532 nm (β(2ω)BSO=(2 ± 0.4)× 10−9cm W−1, β(2ω)BGO=(3.7 ± 0.7)× 10−9cm W−1).

The results of optical limiting investigations of cobalt-doped polyvinylpyrrolidone solutions are presented. The optical limiting studies have shown that this process is due to self-defocusing at the wavelength of 1064 nm and also due to reverse saturable absorption and self-defocusing at the wavelength of 532 nm. The results of measurements on the non-linear optical characteristics of organometallic complexes are presented.

The postjunctional potentials and chronoinotropic reactions of the heart evoked by activation of multimodal neurons and/or left palliai nerve were investigated in three species of land pulmonates: Achatina fulica Ferrussac, Helix lucorum L., Arianta arbustorum L. Both spikes of giant homologous neurons (d-VLN, d-RPLN by A. fulica, command neurons of pneumostoma LPa3, RPa3 by H. lucorum) and stimulation of the peripheral end of the left palliai nerve evoked the similar biphasic inhibitory-excitatory junction potentials in the heart, in mantle muscles and in different parts of visceral complex. The positive chronoinotropic effects of this input in the hearts of whole-mount preparations were modified due to interaction with well-known neural cardioregulating network of the system of intestinal nerve.

We present experimental results obtained on meteor radio links with lengths of 100 and 250 km. The advantage of the “lateral propagation” is demonstrated. Using the “KAMET” computer model, we simulated the propagation of radiowaves along radio links, of up to 600 km. An effective version is proposed for working on radio links of up to 300 km, which is called “tracking the meteor activity maximum.”

The results of third-order nonlinear susceptibilities studies of Fe- and Zn-doped polyvinylpyrrolidone (PVP) aqueous solution in processes of third harmonic generation of Nd:YAG laser radiation are presented. Nonlinear susceptibilities of PVP:Fe and PVP:Zn were calculated to be 5×10-13 esu and 3×10-13 esu respectively. Third harmonic conversion efficiencies in these metallocomplexes were measured to be 8×10-7 and 5×10-7 respectively. The Z-scan method was applied to determine Kerr effect influence on frequency conversion process. The value of nonlinear refractive index of PVP:Fe at the wavelength of λ = 1064 nm was measured to be n2 = - 6.7×10-13 esu.

The process of optical limitation in the aggregated gold hydrosol was studied, which is caused by the nonlinear absorption of the Nd : YAG laser radiation (wavelength λ = 1064 nm) with a picosecond pulse duration. The nonlinear absorption coefficient of gold hydrosol measured by the Z-scanning method is equal to 8.6 × 10–12 cm W–1.

The density distribution of Cs atoms in a metal-vapor cell designed for nonlinear optical and spectroscopic measurements has been investigated by the THG technique. For high heater powers the desnity-distribution function was found to display a dip in the central part of the cell. Explanation of the phenomenon and criteria to eliminate it are proposed.