Redistribution of ions within the active layer and upper permafrost, Yamal, Russia

A landslide-affected slope was chosen to study the ionic migration in the active layer and upper portion of permafrost. The research was conducted in two stages, in 1994 and 2001. Several boreholes, in dry and wet environments of the shearing surface of a 1989-landslide, were drilled. A background borehole on an undisturbed site was sampled as well. Each sample, collected from the core, underwent a conventional chemical cation-anion analysis. The results showed desalinization of the active layer and upper permafrost, which occurred in 7 years. Different migration rates noted for various salts determine change of ionic composition from marine pattern to continental, because mobile ions are washed away by surface and subsurface runoff, while the less mobile ones are accumulating in the upper portion of the active layer due to capillary rise and at the active layer base on a geochemical barrier

Impedimetric determination of kanamycin in milk with aptasensor based on carbon black‐oligolactide composite

The determination of antibiotics in food is important due to their negative effect on human health related to antimicrobial resistance problem, renal toxicity, and allergic effects. We propose an impedimetric aptasensor for the determination of kanamycin A (KANA), which was assembled on the glassy carbon electrode by the deposition of carbon black in a chitosan matrix followed by carbodiimide binding of aminated aptamer mixed with oligolactide derivative of thiacalix[4]arene in a cone configuration. The assembling was monitored by cyclic voltammetry, electrochemical impedance spectroscopy, and scanning electron microscopy. In the presence of the KANA, the charge transfer resistance of the inner interface surprisingly decreased with the analyte concentration within 0.7 and 50 nM (limit of detection 0.3 nM). This was attributed to the partial shielding of the negative charge of the aptamer and of its support, a highly porous 3D structure of the surface layer caused by a macrocyclic core of the carrier. The use of electrostatic assembling in the presence of cationic polyelectrolyte decreased tenfold the detectable concentration of KANA. The aptasensor was successfully tested in the determination of KANA in spiked milk and yogurt with recoveries within 95% and 115%. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.Russian Science Foundation, RSF: 16‐13‐000051/0419/20Funding: I.S. acknowledges financial support from the Russian Science Foundation (grant no. 16‐13‐00005) in the synthesis and application in the biosensor platform of the oligolactides bearing thiacalix[4]arene fragments. T.H. acknowledges funding from the European Union’s Horizon 2020 Research and Innovation Program underthe Marie Sklodowska‐Curie grant agreement no. 690898 and from the Science Grant Agency VEGA, project No.1/0419/20

Long-lived photoinduced absorption in granular molybdenum disulfide thin films

© 2018 Institute of Physics Publishing. All rights reserved. We present results of the differential photoinduced absorption spectra investigation of the molybdenum disulfide nanogranular thin films. The films were produced by means of a sulfurization of pre-deposited by magnetron sputtering thin molybdenum films. It has been shown that photoexcitation with the light quanta with the energy higher than the bandgap leads to a modification of the absorption spectra in the visible range. Possible nature of the photoinduced absorption spectra will be discussed

Considerable enhancement of the critical current in a superconducting film by magnetized magnetic strip

We show that a magnetic strip on top of a superconducting strip magnetized in a specified direction may considerably enhance the critical current in the sample. At fixed magnetization of the magnet we observed diode effect - the value of the critical current depends on the direction of the transport current. We explain these effects by a influence of the nonuniform magnetic field induced by the magnet on the current distribution in the superconducting strip. The experiment on a hybrid Nb/Co structure confirmed the predicted variation of the critical current with a changing value of magnetization and direction of the transport current.Comment: 6 pages, 7 figure

Electrochemical Sensing of Interactions between DNA and Charged Macrocycles

In this work, we investigated aggregation of native DNA and thiacalix[4]arene derivative bearing eight terminal amino groups in cone configuration using various redox probes on the glassy carbon electrode. It was shown that sorption transfer of the aggregates on the surface of the electrode covered with carbon black resulted in changes in electrostatic interactions and diffusional permeability of the surface layer. Such changes alter the signals of ferricyanide ion, methylene green and hydroquinone as redox probes to a degree depending on their specific interactions with DNA and own charge. Inclusion of DNA in the surface layer was independently confirmed by scanning electron microscopy, electrochemical impedance spectroscopy and experiments with doxorubicin as a model intercalator. Thermal denaturing of DNA affected the charge separation on the electrode interface and the signals of redox probes. Using hydroquinone, less sensitive to electrostatic interactions, made it possible to determine from 10 pM to 1.0 nM doxorubicin (limit of detection 3 pM) after 10 min incubation. Stabilizers present in the commercial medications did not alter the signal. The DNA sensors developed can find future application in the assessment of the complexes formed by DNA and macrocycles as delivery agents for small chemical species. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Funding: This research was funded by Russian Science Foundation (grant no. 21-73-20067)

ИССЛЕДОВАНИЕ ДИНАМИЧЕСКОГО ПОВЕДЕНИЯ КОНИЧЕСКОГО ОБТЕКАТЕЛЯ ЛЕТАТЕЛЬНОГО АППАРАТА ПРИ СЛОЖНОМ ТЕРМОСИЛОВОМ НАГРУЖЕНИИ

The article deals with the dynamic behavior of the unevenly heated thin-walled conical shell of revolution of the aircraft fairing type under the loading conditions by shock wave in the gaseous environment, approximated by travelling load. The displacements of the shell, resulting from the preliminary uneven heating, are determined from the solution of the equations of thermoelastic equilibrium. Solution of the dynamic problem consists of the integration of the nonlinear equations of shell motion at the assigned initial displacement, zero initial velocities and boundary conditions, corresponding to the fastening of fairing. As a result of the solution of the presented problem the amplitudes of the fluctuations of the fairing nose edge are determined. It allows to determine the stress-strained state of shell for the purposes of the determination of its bearing capacity.В статье исследуется динамическое поведение неравномерно нагретой тонкостенной конической оболочки вращения типа обтекателя летательного аппарата в условиях нагружения ударной волной в газовой среде, аппроксимируемой подвижной нагрузкой. Перемещения оболочки, возникающие в результате предварительного неравномерного нагрева, определяются из решения уравнений термоупругого равновесия. Решение динамической задачи состоит в интегрировании нелинейных уравнений движения оболочки при заданных начальных смещениях, нулевых начальных скоростях и граничных условиях, соответствующих закреплению обтекателя. В результате решения представленной задачи определяются амплитуды колебаний носка обтекателя. Это позволяет определять напряженно-деформированное состояние оболочки в целях определения ее несущей способности

HUWE1 E3 ligase promotes PINK1/PARKINindependent mitophagy by regulating AMBRA1 activation via IKKa

The selective removal of undesired or damaged mitochondria by autophagy, known as mitophagy, is crucial for cellular homoeostasis, and prevents tumour diffusion, neurodegeneration and ageing. The pro-autophagic molecule AMBRA1 (autophagy/beclin-1 regulator-1) has been defined as a novel regulator of mitophagy in both PINK1/PARKIN-dependent and -independent systems. Here, we identified the E3 ubiquitin ligase HUWE1 as a key inducing factor in AMBRA1-mediated mitophagy, a process that takes place independently of the main mitophagy receptors. Furthermore, we show that mitophagy function of AMBRA1 is post-translationally controlled, upon HUWE1 activity, by a positive phosphorylation on its serine 1014. This modification is mediated by the IKKα kinase and induces structural changes in AMBRA1, thus promoting its interaction with LC3/GABARAP (mATG8) proteins and its mitophagic activity. Altogether, these results demonstrate that AMBRA1 regulates mitophagy through a novel pathway, in which HUWE1 and IKKα are key factors, shedding new lights on the regulation of mitochondrial quality control and homoeostasis in mammalian cells