Structure of Core-Shell Ni/Au Nanoparticles Synthesized in Two-Stage Process From Aqueous Salt Solutions

Core-shell Ni/Au nanoparticles are synthesized in a two-stage process in aqueous solutions. The core-shell structure of the synthesized particles is proven by using results of HRTEM, TEM, SAXS and CVA methods. The thickness of the core is estimated at 1 nm and it is formed from 1–2 layers of mutually oriented gold crystallites. The CVA results show that the Au-shells are nanoporous, and that a layer of nickel oxidation products is formed. These results were obtained by using Vis spectrophotometer, TEM, HRTEM, SAXS, CVA and elemental analysis

СРАВНЕНИЕ МОРФОЛОГИЧЕСКИХ И ХИМИЧЕСКИХ СВОЙСТВ СФЕРИЧЕСКИХ И ИГОЛЬЧАТЫХ КАЛЬЦИЙ-ФОСФАТНЫХ БИОНОВ

Aim. To compare morphological properties, mineral, and organic profile of spherical calcium phosphate bions (SCPB) and needle calcium phosphate bions (NCPB) for the assessment of the CPB-specific endothelial toxicity in models of mild or severe hypercalcemia/hyperphosphatemia in the further studies.Methods. Both SCPB and NCPB were artificially synthesized employing blood-mimetic medium either moderately or significantly supersaturated of calcium and phosphorus salts. Size and shape of SCPB and NCPB were investigated by scanning and transmission electron microscopy and atomic force microscopy. Elemental analysis was performed utilizing energy-dispersive X-ray spectroscopy, atomic emission spectroscopy, and CHNSO analysis, functional groups were examined using Fourier-transform infrared spectroscopy and Raman spectroscopy while chemical formula was identified by X-ray powder diffraction analysis. Protein profile of SCPB and NCPB was screened employing sodium dodecyl sulfate polyacrylamide gel electrophoresis following silver staining.Results. SCPB were visualized as crystalline spherical spongeous particles of 80-200 nm diameter and mean diameter of around 120 nm while NCPB represented needle crystals of a similar diameter. Both SCPB and NCPB had similar crystallinity, surface charge and tended to form clusters of several particles. Furthermore, both SCPB and NCPB were composed of carbon, oxygen, hydrogen, nitrogen, calcium, and phosphorus, contained phosphate (PO4 3-), carbonate (CO3 2-), and hydroxyl (OH- ) functional groups, and consisted of hydroxyapatite (Ca10(PO4 )6 (OH)2 ) and carbonate-hydroxyapatite (Ca10(PO4)3 (CO3)3 (OH)2 ). In addition, protein profile of SCPB and NCPB was similar and notable for the abundant albumin and fetuin A levels.Conclusion. Having similar size, surface charge, extent of crystallinity, and chemical composition, SCPB and NCPB possess a different shape. Цель Сравнить морфологию, минеральный и органический профиль сферических кальций-фосфатных бионов (СКФБ) и игольчатых кальций-фосфатных бионов (ИКФБ), необходимых для оценки эндотелиотоксического действия КФБ при моделировании умеренной и тяжелой гиперкальциемии/гиперфосфатемии в последующих исследованиях. Материалы и методы СКФБ и ИКФБ были искусственно синтезированы посредством умеренного и выраженного перенасыщения имитирующей состав крови среды солями кальция и фосфора. Размерность и форма СКФБ и ИКФБ были изучены при помощи сканирующей и просвечивающей электронной микроскопии и атомно-силовой микроскопии. Элементный анализ проводился посредством энергодисперсионной рентгеновской спектроскопии, атомно-эмиссионной спектроскопии и CHNSO-анализа, функциональные группы идентифицировались при помощи инфракрасной спектроскопии с преобразованием Фурье и спектроскопии комбинационного рассеяния света, формула входящих в состав бионов химических соединений и степень их кристалличности определялась методом рентгеновской порошковой дифрактометрии. Белковый профиль СКФБ и ИКФБ был исследован путем электрофореза в полиакриламидном геле в присутствии додецилсульфата натрия с последующим окрашиванием нитратом серебра. Результаты СКФБ визуализировались как кристаллические сферические частицы губчатой структуры диаметром 80–200 нм и средним диаметром около 120 нм, в то время как ИКФБ представляли собой игольчатые кристаллы такого же диаметра. Как СКФБ, так и ИКФБ имели схожий поверхностный заряд и были склонны к агрегации. СКФБ и ИКФБ состояли из углерода, кислорода, водорода, азота, кальция и фосфора, содержали фосфатные (PO4 3-), карбонатные (CO3 2-) и гидроксильные (OH- ) группы и состояли из гидроксиапатита (Ca10(PO4 ) 6 (OH)2 ) и карбонат-гидроксиапатита (Ca10(PO4 ) 3 (CO3 ) 3 (OH)2 ). Кроме того, СКФБ и ИКФБ обладали идентичной степенью кристалличности и схожим белковым профилем с преобладанием альбумина и фетуина-А над остальными белками. Заключение СКФБ и ИКФБ отличаются лишь формой, имея схожие размерность, поверхностный заряд, степень кристалличности и химический соста

Detector response and calibration of the cosmic-ray detector of the Sileye-3/Alteino experiment

The experiment Sileye-3/Alteino is constituted by a cosmic-ray silicon detector and an electroencephalograph. The main scientific aims include the investigation of the Light Flash phenomenon, the study of astronaut brain activity in space when subject to cosmic rays, the measurement of cosmic rays and the radiation environment inside the International Space Station. The experiment was operating on board the station from 27 April to 5 May 2002. The cosmic-ray detector is composed of eight silicon strip planes triggered by two scintillators placed on top and bottom of the stack. The detector is capable of identifying nuclei from B to As in the energy range above similar or equal to 60 MeV/n. Also protons and lighter particles are registered although with a reduced efficiency. The instrument was active in the Pits module of the station for 130 h. In this work, we describe the silicon strip detector characteristics and its calibration performed using cosmic-ray nuclei. (c) 2005 COSPAR. Published by Elsevier Ltd. All rights reserved

SRG X-ray orbital observatory. Its telescopes and first scientific results

The orbital observatory Spectrum-Roentgen-Gamma (SRG), equipped with the grazing-incidence X-ray telescopes Mikhail Pavlinsky ART-XC and eROSITA, was launched by Roscosmos to the Lagrange L2 point of the Sun-Earth system on July 13, 2019. The launch was carried out from the Baikonur Cosmodrome by a Proton-M rocket with a DM-03 upper stage. The German telescope eROSITA was installed on SRG under an agreement between Roskosmos and the DLR, the German Aerospace Agency. In December 2019, SRG started to perform its main scientific task: scanning the celestial sphere to obtain X-ray maps of the entire sky in several energy ranges (from 0.2 to 8 keV with eROSITA, and from 4 to 30 keV with ART-XC). By mid-June 2021, the third six-month all-sky survey had been completed. Over a period of four years, it is planned to obtain eight independent maps of the entire sky in each of the energy ranges. The sum of these maps will provide high sensitivity and reveal more than three million quasars and over one hundred thousand massive galaxy clusters and galaxy groups. The availability of eight sky maps will enable monitoring of long-term variability (every six months) of a huge number of extragalactic and Galactic X-ray sources, including hundreds of thousands of stars with hot coronae. The rotation of the satellite around the axis directed toward the Sun with a period of four hours enables tracking the faster variability of bright X-ray sources during one day every half year. The chosen strategy of scanning the sky leads to the formation of deep survey zones near both ecliptic poles. The paper presents sky maps obtained by the telescopes on board SRG during the first survey of the entire sky and a number of results of deep observations performed during the flight to the L2 point in the frame of the performance verification program.(Abriged)Comment: 30 pages, 46 figures. Astronomy & Astrophysics, 656, A132, 2021. Abstract abridge