Исследование микроструктуры и фазового состава водородостойких покрытий из самофлюсующихся сплавов н композиций на их основе

The paper presents results of theoretical and experimental investigations of peculiar features in formation of micro-structure and phase composition of protective (hydrogen-resistant) coatings of self-fluxing alloys and compositions on their basis at surface (high frequency current), solid (in a furnace) and laser flashings.Представлены результаты теоретических и экспериментальных исследований особенностей формирования, микроструктуры и фазового состава защитных (водородостойких) покрытий из самофлюсующихся сплавов и композиций на их основе при поверхностном (ТВЧ), объемном (в печи) и лазерном оплавлениях

Синтез наноразмерных кобальт-цинковых ферритов методом низкотемпературного распыления с последующим термолизом

Co0,65Zn0,35Fe2O4 nanoparticles were produced by spray-drying in air in presence of NaCl from the solution of nitrates, as well as from the suspension of coprecipitated particles. The precursors obtained were annealed at 300–900 °C in the matrix of the inert component in order to increase the crystallinity degree without substantial increase of the nanoparticle size. Microstructure, morphology and magnetic properties of nanoparticles were studied by XRD, FT-IR spectroscopy, TEM / SEM and magnetometry. For the ferrites obtained from nitrate solutions partial oxidation of Co2+ ions to Co3+ occurs, which leads to the formation of two spinel phases, ferrite and cobaltite. With the increase of annealing temperature the content of cobaltite decreases and content of ferrite increases. No cobaltite formation was observed for annealing the spray-dried suspension. An increase in the temperature of the heat treatment leads to partial recrystallization of the particles and the ordering of the ferrite crystal structure, which causes an increase in the specific magnetization of the materials: from 32.8 emu/g (before annealing) to 91.3 emu/g (annealing at 900 ° C). The average diameter of nanoparticles after heat treatment does not exceed 100 nm.Наночастицы состава Co0,65Zn0,35Fe2O4 получали методом распылительной сушки на воздухе в присутствии NaCl из раствора нитратов, а также из суспензии предварительно осажденных частиц. Полученные прекурсоры подвергали термообработке в диапазоне 300–900 °С в матрице инертного компонента с целью увеличения степени кристалличности без существенного роста размеров наночастиц. Микроструктуру, морфологию и магнитные свойства наночастиц исследовали методами РФА, ИК-спектроскопии, ПЭМ/СЭМ и магнитометрии. При получении ферритов из растворов солей происходит частичное окисление ионов Co2+ до Co3+, что приводит к образованию двух шпинельных фаз – феррита и кобальтита. С ростом температуры обжига доля кобальтита снижается, а феррита – растет. При распылении и последующем обжиге суспензий наночастиц формирования фазы кобальтита не происходит. Повышение температуры термообработки приводит к частичной рекристаллизации частиц и упорядочиванию кристаллической структуры феррита, что вызывает рост удельной намагниченности материалов: от 32,79 Ам2 кг–1 (до обжига) до 91,3 Ам2 кг–1 (обжиг при 900 °С). При этом средний диаметр наночастиц после термообработки не превышает 100 нм

The Integrin Receptor in Biologically Relevant Bilayers: Insights from Molecular Dynamics Simulations

Integrins are heterodimeric (αβ) cell surface receptors that are potential therapeutic targets for a number of diseases. Despite the existence of structural data for all parts of integrins, the structure of the complete integrin receptor is still not available. We have used available structural data to construct a model of the complete integrin receptor in complex with talin F2–F3 domain. It has been shown that the interactions of integrins with their lipid environment are crucial for their function but details of the integrin/lipid interactions remain elusive. In this study an integrin/talin complex was inserted in biologically relevant bilayers that resemble the cell plasma membrane containing zwitterionic and charged phospholipids, cholesterol and sphingolipids to study the dynamics of the integrin receptor and its effect on bilayer structure and dynamics. The results of this study demonstrate the dynamic nature of the integrin receptor and suggest that the presence of the integrin receptor alters the lipid organization between the two leaflets of the bilayer. In particular, our results suggest elevated density of cholesterol and of phosphatidylserine lipids around the integrin/talin complex and a slowing down of lipids in an annulus of ~30 Å around the protein due to interactions between the lipids and the integrin/talin F2–F3 complex. This may in part regulate the interactions of integrins with other related proteins or integrin clustering thus facilitating signal transduction across cell membranes

Theoretical and Experimental Investigations of Peculiar Features in Micro-Structure Formation and Phase Composition of Hydrogen-Resistant Coatings of Self-Fluxing Alloys and Compositions on Their Basis

The paper presents results of theoretical and experimental investigations of peculiar features in formation of micro-structure and phase composition of protective (hydrogen-resistant) coatings of self-fluxing alloys and compositions on their basis at surface (high frequency current), solid (in a furnace) and laser flashings

Acetaminophen-induced fulminant liver failure (clinical case presentation and a review of the literature)

Acetaminophen (AAP) is one of the most common and widely used antipyretic drugs, but its overdose is the leading cause of fulminant hepatic insufficiency in the world. Mechanisms of liver damage at the use of toxic doses of AAP are caused by the transformation of the isoform of cytochrome P450 (CYP2E1, CYP2A6) into a reactive metabolite, N-acetyl-parabenzoquinonimine (NAPQI), which plays a major role in hepatotoxicity. Another mechanism of hepatotoxicity includes the formation of peroxynitrite – a toxic free radical produced in the mitochondria, which causes oxidative damage. In addition to liver damage in case of acetaminophen poisoning, nephrotoxic effect can occur. Potential mechanisms of nephrotoxicity in overdose of AAP are presented, caused by cytochrome P450, as well as prostaglandin synthetase and enzyme N-deacetylase are described. In the clinical case described by us, the development of fulminant hepatic insufficiency against the background of acetaminophen administration led to the development of a coma along with the kidney damage, however, a stable positive dynamics, was achieved during treatment. In the catamnesis 2.5 years later, there were no signs of fibrosis or cirrhosis of the liver