Construction and implementation of a mathematical model for damping vibrations of high-rise buildings and structures using reactive dampers

The problem of developing a computational model of an active vibration damping system of a high-rise building during an earthquake using a simple and suitable calculation scheme for high-rise buildings is considered. An approximate finite element model is presented that adequately describes the dynamic characteristics of a high-rise building. A mathematical model of a steel lattice tower is considered as an example. The ratio equations and displacement difference equations describing the behavior of reactive dampers installed in the tower are presented. An approach to optimizing the parameters of relative motion is presented. The calculation of vibration damping of a tower with reactive dampers installed on one and two levels is shown. The classification of forces with different physical properties and affecting the movement of mechanical systems is presented

MicroRNAs are minor constituents of extracellular vesicles that are rarely delivered to target cells

Mammalian cells release different types of vesicles, collectively termed extracellular vesicles (EVs). EVs contain cellular microRNAs (miRNAs) with an apparent potential to deliver their miRNA cargo to recipient cells to affect the stability of individual mRNAs and the cells’ transcriptome. The extent to which miRNAs are exported via the EV route and whether they contribute to cell-cell communication are controversial. To address these issues, we defined multiple properties of EVs and analyzed their capacity to deliver packaged miRNAs into target cells to exert biological functions. We applied well-defined approaches to produce and characterize purified EVs with or without specific viral miRNAs. We found that only a small fraction of EVs carried miRNAs. EVs readily bound to different target cell types, but EVs did not fuse detectably with cellular membranes to deliver their cargo. We engineered EVs to be fusogenic and document their capacity to deliver functional messenger RNAs. Engineered fusogenic EVs, however, did not detectably alter the functionality of cells exposed to miRNA-carrying EVs. These results suggest that EV-borne miRNAs do not act as effectors of cell-to-cell communication. Author summary: The majority of metazoan cells release vesicles of different types and origins, such as exosomes and microvesicles, now collectively termed extracellular vesicles (EVs). EVs have gained much attention because they contain microRNAs (miRNAs) and thus could regulate their specific mRNA targets in recipient or acceptor cells that take up EVs. Using a novel fusion assay with superior sensitivity and specificity, we revisited this claim but found no convincing evidence for an efficient functional uptake of EVs in many different cell lines and primary human blood cells. Even EVs engineered to fuse and deliver their miRNA cargo to recipient cells had no measurable effect on target mRNAs in very carefully controlled, quantitative experiments. Our negative results clearly indicate that EVs do not act as vehicles for miRNA-based cell-to-cell communication

High - Temperature Superconductivity in Iron Based Layered Compounds

We present a review of basic experimental facts on the new class of high - temperature superconductors - iron based layered compounds like REOFeAs (RE=La,Ce,Nd,Pr,Sm...), AFe_2As_2 (A=Ba,Sr...), AFeAs (A=Li,...) and FeSe(Te). We discuss electronic structure, including the role of correlations, spectrum and role of collective excitations (phonons, spin waves), as well as the main models, describing possible types of magnetic ordering and Cooper pairing in these compounds.Comment: 43 pages, 30 figures, review talk on 90th anniversary of Physics Uspekh

Comparison of Free Radical Levels in the Aerosol from Conventional Cigarettes, Electronic Cigarettes, and Heat-Not-Burn Tobacco Products

Aerosols from electronic cigarettes and heat-not-burn tobacco products have been found to contain lower levels of almost all compounds from the list of Harmful and Potentially Harmful Constituents known to be present in tobacco products and tobacco smoke than smoke from conventional cigarettes. Free radicals, which also pose potential health risks, are not considered in this list, and their levels in the different product types have not yet been compared under standardized conditions. We compared the type and quantity of free radicals in mainstream aerosol of 3R4F research cigarettes, two types of electronic cigarettes, and a heat-not-burn tobacco product. Free radicals and NO in the gas phases were separately spin trapped and quantified by electron paramagnetic resonance (EPR) spectroscopy by using a smoking machine for aerosol generation and a flow-through cell to enhance reproducibility of the quantification. Particulate matter was separated by a Cambridge filter and extracted, and persistent radicals were quantified by EPR spectroscopy. Levels of organic radicals for electronic cigarettes and the heat-not-burn product, as measured with the PBN spin trap, did not exceed 1% of the level observed for conventional cigarettes and were close to the radical level observed in air blanks. The radicals found in the smoke of conventional cigarettes were oxygen centered, most probably alkoxy radicals, whereas a signal for carbon-centered radicals near the detection limit was observed in aerosol from the heat-not-burn product and electronic cigarettes. The NO level in aerosol produced by electronic cigarettes was below our detection limit, whereas for the heat-not-burn product, it reached about 7% of the level observed for whole smoke from 3R4F cigarettes. Persistent radicals in particulate matter could be quantified only for 3R4F cigarettes. Aerosols from vaping and heat-not-burn tobacco products have much lower free radical levels than cigarette smoke, however, the toxicological implications of this finding are as yet unknownISSN:0893-228XISSN:1520-501

Phase transition dynamics of single optically trapped aqueous potassium carbonate particles

ISSN:1463-9084ISSN:1463-907

Novel Sources of Resistance to <i>Stagonospora nodorum</i> and Role of Effector-Susceptibility Gene Interactions in Wheat of Russian Breeding

Virulence factors of the pathogen Stagonospora nodorum Berk. are numerous necrotrophic effectors (NEs) (SnTox), which interact with the products of host susceptibility genes (Snn), causing the development of the disease. In this study, 55 accessions of bread spring and winter wheat were screened for sensitivity to NEs SnToxA, SnTox1, and SnTox3 using different isolates of S. nodorum. In the studied panel of wheat, 47 accessions were modern commercial cultivars grown in Russia and 8 cultivars were historic wheat accessions from the N. I. Vavilov Institute of Plant Genetic Resources in Russia. In general, our wheat panel differed from other wheat collections with available data in that it was less sensitive to SnToxA and SnTox3, and more sensitive to SnTox1. Six sources of strong SNB resistance were identified in our wheat panel. In addition, during the study, wheat cultivars were identified as appropriate objects in which to study the different effects of SnTox-Snn interactions, which is important for marker-assisted selection for SNB resistance. The current study has shown, for the first time, that the expression level of Snn1 and Tsn1 susceptibility genes and the disease severity of the different wheat cultivars are interconnected. Future work should focus on the deep characterization of SnTox-Snn interactions at the molecular level

Structure and Properties of Highly Porous Alumina-Based Ceramic Materials after Heating by Concentrated Solar Radiation

Three ceramic fibrous materials of the Al2O3-SiO2 system with different densities have been treated using concentrated solar radiation. The experiment was performed using technological capabilities of the Big Solar Furnace in the 2 modes: the first mode includes heating up to 1400–1600 °C, holding for 1.5–2 h; the second mode (the fusion mode) includes heating up to 1750–1900 °C until the sample destruction, which is accompanied by fusion. Upon completion of the experiment, the phase composition, microstructure, and compressive strength of the materials were studied. It was shown that the investigated materials retained their fibrous structure under prolonged treatment in the first mode up to temperatures of 1600 °C. The phase composition of the ceramic materials changes during the experiment, and with a decrease in the density, the modification is more pronounced. Treatment of all three materials under study in the fusion mode resulted in the formation of the eutectic component in the form of spherulites. The compressive strength of the materials was found to be slightly reduced after exposure to concentrated solar radiation

Structure and Properties of Highly Porous Alumina-Based Ceramic Materials after Heating by Concentrated Solar Radiation

Three ceramic fibrous materials of the Al2O3-SiO2 system with different densities have been treated using concentrated solar radiation. The experiment was performed using technological capabilities of the Big Solar Furnace in the 2 modes: the first mode includes heating up to 1400&ndash;1600 &deg;C, holding for 1.5&ndash;2 h; the second mode (the fusion mode) includes heating up to 1750&ndash;1900 &deg;C until the sample destruction, which is accompanied by fusion. Upon completion of the experiment, the phase composition, microstructure, and compressive strength of the materials were studied. It was shown that the investigated materials retained their fibrous structure under prolonged treatment in the first mode up to temperatures of 1600 &deg;C. The phase composition of the ceramic materials changes during the experiment, and with a decrease in the density, the modification is more pronounced. Treatment of all three materials under study in the fusion mode resulted in the formation of the eutectic component in the form of spherulites. The compressive strength of the materials was found to be slightly reduced after exposure to concentrated solar radiation

Applying pseudowave transformation in transient electromagnetic prospecting for recognition of inclined geological boundaries

Актуальность. Метод нестационарных электромагнитных зондирований или зондирований становлением поля является востребованным инструментом при поиске и разведке месторождений различного типа полезных ископаемых. Современные задачи электроразведки требуют использования установок с большим числом источников и приёмников. Для подобного типа установок задача интерпретации полученных данных является весьма ресурсоемкой. Отсюда вытекает острая необходимость развития методов обработки и интерпретации данных, полученных в результате импульсных электромагнитных зондирований. Одним из возможных путей такого развития могут послужить трансформации данных зондирований становлением в пространство решений волнового уравнения. Цель: применить метод волновой трансформации к данным зондирований становлением, зарегистрированным над проводящими средами с наклонной границей в многоразносных установках, для получения новых качественных оценок исследуемого геоэлектрического разреза. Методика исследования базируется на новых численных алгоритмах для устойчивого преобразования данных зондирований становлением в волновую область. Исходные данные для отладки процедур трансформации (расчётные кривые становления поля) были получены с использованием программного комплекса MODEM3D, который предназначен для прямого моделирования переходных процессов диффузии электромагнитных полей. Результаты. Были получены псевдоволновые трансформанты сигналов нестационарных электромагнитных зондирований в средах с наклонной границей, и построены их годографы. Полученные наборы трасформаций позволяют выделить линию выхода наклонного контакта на дневную поверхность. Установлено, что перекрывающие наносы ослабляют максимумы псевдоволновых трансформаций и снижают возможность точной локализации линии выхода наклонной границы. Рассмотрено поведение тороидальных вихревых токов в зависимости от времени для модели геологической среды с наклонной границей.Relevance. Transient electromagnetic soundings is the method in-demand of electric survey applied for mineral deposits prospecting. Modern geoelectric problems require the usage of multichannel devices. For such devices the processing and interpretation problem becomes very resource intensive. Thus, the further development of interpretation methods is highly recommended. One of the possible ways of such development is the usage of wavefield transformation for transient electromagnetic data. The main aim of the research is to apply the wavefield transformation to the transient electromagnetic data measured in multireceivers systems in conductive media with inclined boundary for obtaining new qualitative estimations for the geological media on study. Method of research is based on new numerical algorithms for the stable wavefiled transformations of transient electromagnetic soundings data. Input data for transformation checkout (calculated three-dimensional curves of transient electromagnetic field response) was received using MODEM3D software package, which is designed for direct modeling of transient electromagnetic fields. Results. Pseudowave transformations of transient electromagnetic soundings for the conductive media with inclined boundary were obtained. These pseudowave transformations are used to plot travel-time curves. The resulting sets of transformations allow allocating the outcrop of the inclined contact on the surface. It is established that overlapping sediments weaken the maxima of pseudowave transformations and reduce the possibility of exact localization of the outcrop of the inclined contact. The behavior of toroidal vertical currents depending on time in the media with inclined boundary was considered