Content of biologically active substances in the raw materials of some Siberian Saussurea species

This paper focuses on the chemical composition of five Siberian Saussurea species: S. frolowii, S. controversa, S. latifolia, S. parviflora and S. salicifolia. Four groups of substances were found in dry mass of these plants: phenolic compounds (flavonoids, tannins), carotenoids, pectins and saponins. Quantitative spectrophotometric analysis revealed a high content of flavonoids, catechins, tannins, carotenoids and saponins in some samples. Leaves of S. parviflora and S. latifoliacontain high contents of flavonoids (greater than 3.2 %). The greatest amount of catechins accumulates in the leaves of S. parviflora and S. frolowii. Due to the high content of tannins S. parviflora and S. latifoliaare noteworthy. Leaves of S. parvifloraand S. latifolia accumulate a particularly large number of carotenoids. Leaves of S. parviflora and S. controversaare particularly rich in saponins. Our results confirm the hypothesis about the prospects of the use of these species for the development of herbal medicines

Microstructure and crystallographic texture of silicon iron modified by torsion under quasihydrostatic pressure

The electron backscatter diffraction, X-ray diffraction analysis, electromotive force instantaneous measurement, microhardness and coercive force measurement techniques are used to explore the development of the microstructure, crystallographic texture and physico-mechanical properties of silicon iron (Fe-3% Si) alloy under quasi-hydrostatic pressure in a Bridgman anvil. It is found that the alloy deformation is accompanied by its significant hardenin

Микрополосковые направленные ответвители УВЧ и СВЧ диапазонов

The paper gives a review to analyse the outcomes achieved in the field of micro-strip directional couplers within 2010 – 2017.Considers design features of over twenty original or modified quadrature micro-strip directional couplers within ultrahigh (UHF) and super-high frequency (SHF) bands. The focus is on the ways to reduce overall dimensions of traditional loopback, printed and coupled couplers, enhance their use in several frequency bands, suppress higher order harmonics up to the sixth, provide broad-banding operation frequency to several octaves, change a type of the laterally-coupled coupler directionality from the counter-directional to the co-directional and trans-directional ones. The results obtained are achieved due to the following: the change of the quarter-wave line segments for their equivalent micro-strip “П”- and “T”- like structures and their combinations, the quasi-fractal topological implementation of devices, the use of composite transmission lines with the properties of meta-materials, the use of defects of various shapes in the ground plane, the samples in the signal layer of metallization, the low-pass filters in combination version of high-resistance and low-resistance lines, the use of special-form coupling apertures in a multilayer response which allows to compensate for the differences in phase lengths of the segments of connected lines for the even- and odd-order modes, thereby enabling significant improvement of  coupler characteristics.The paper briefly describes coupler topologies, equivalent circuits and device layouts. Shows amplitude-frequency and phase-frequency characteristics simulated in computer-aided design systems. Also presents measuring results of the fabricated mock-ups of micro-strip directional couplers. The results obtained may be of interest to the creators of SHF devices and those involved in further investigation to seek and improve couplers of known designs.В обзоре проведен анализ результатов, достигнутых в области микрополосковых направленных ответвителей за период с 2010 по 2017 годы.В работе рассмотрены конструктивные особенности более двадцати оригинальных или модифицированных квадратурных микрополосковых направленных ответвителей функционирующих в УВЧ и СВЧ диапазонах. Большое внимание уделяется способам уменьшения габаритных размеров традиционных шлейфных, печатных и ответвителей на связанных линиях, расширению функциональных возможностей по их применению в нескольких частотных диапазонах, подавлению гармоник высших порядков вплоть до шестой, расширению рабочей полосы частот до нескольких октав, изменению типа направленности ответвителей с боковой связью с противонаправленного на сонаправленную и транснаправленную. Полученные результаты достигнуты благодаря замещению четвертьволновых отрезков линий на их эквивалентные микрополосковые П – и T– структуры и их комбинации, квазифрактальной топологической реализации устройств, применению композитных линий передачи, обладающими свойствами метаматериалов, использованию дефектов различной формы в плоскости заземления, выборкам в сигнальном слое металлизации, фильтрам нижних частот в варианте совмещения высокоомных и низкоомных линий, применению апертур связи специальной формы в многослойных ответвителях с лицевой связью, которые позволяют компенсировать разности фазовых длин отрезков связанных линий для четной и нечетной мод, что позволило значительно улучшить характеристики ответвителей. Дано краткое описание топологий ответвителей, эквивалентных схем и макетов устройств, приведены амплитудно-частотные и фазо-частотные характеристики, полученные с помощью моделирования в системах автоматизированного проектирования, также представлены результаты измерений изготовленных макетов микрополосковых направленных ответвителей. Результаты работы могут быть интересны разработчикам СВЧ устройств, а также с точки зрения дальнейшего изучения с целью поиска и совершенствования известных конструкций ответвителей

The effect of equal-channel angular pressing on microstructure, mechanical properties, and biodegradation behavior of magnesium alloyed with silver and gadolinium

The effect of equal channel angular pressing (ECAP) on the microstructure, texture, mechanical properties, and corrosion resistance of the alloys Mg-6.0%Ag and Mg-10.0%Gd was studied. It was shown that ECAP leads to grain refinement of the alloys down to the average grain size of 2–3 μm and 1–2 μm, respectively. In addition, in both alloys the precipitation of fine particles of phases Mg$_{54}$Ag$_{17}$ and Mg$_{5}$Gd with sizes of ~500–600 and ~400–500 nm and a volume fraction of ~9% and ~8.6%, respectively, was observed. In the case of the alloy Mg-6.0%Ag, despite a significant grain refinement, a drop in the strength characteristics and a nearly twofold increase in ductility (up to ~30%) was found. This behavior is associated with the formation of a sharp inclined basal texture. For alloy Mg-10.0%Gd, both ductility and strength were enhanced, which can be associated with the combined effect of significant grain refinement and an increased probability of prismatic and basal glide. ECAP was also shown to cause a substantial rise of the biodegradation rate of both alloys and an increase in pitting corrosion. The latter effect is attributed to an increase in the dislocation density induced by ECAP and the occurrence of micro-galvanic corrosion at the matrix/particle interfaces

Magnetic resonances in EuSn2_2As2_2 single crystal

In this work, we report the broad-band ferromagnetic resonance spectroscopy of EuSn$_2$As$_2$ single crystals at different temperatures in combination with magnetization measurements and structural characterization. We observe conventional collective acoustic resonance mode of the A-type antiferromagnetic spin-flop phase in the Eu sub-lattice, and its transition to the paramagnetic resonance above the ordering temperature. Furthermore, we observe reproducibly additional well-defined spectral line. The origin of the additional line remains unclear. However, its temperature dependence attributes it to magnetism in the Eu sub-lattice.Comment: 6 pages, 4 figures, 34 reference

Возможности мультиспиральной компьютерной томографии в диагностике рака ротовой полости и языка

The aim: to determine if the multislice computed tomography is effective in detecting the oral cavity and tongue cancer.Materials and methods. A data set from MSCT research study containing records from 243 patients aged between 19 and 89 has been analyzed. The data included personal records of two groups: 124 (51.0%) patients of the main group with the diagnosis “tongue and oral cavity cancer” and 119 (49.0%) patients the control group, receiving assessment and treatment at Oncology in-patient specialized clinic №1, during a period from 2012 to 2016 years. The findings were compared to information received from clinical, instrumental examination and morphological results.Results. Some typical CT signs of tongue and oral cavity cancer are identified as following: the asymmetry of anatomical structures; tissue densities ranging +39 HU...+43 HU (min/max −13…+86 HU); obliteration of fatty layers; the postcontrast densities increasing on 36–47 HU (min/max +26…+68 HU); the presence of a hypodense contrast agent-avoiding area; signs of additional tissue; signs of local tissue defect. Similar calculations are made for the four signs of the greatest figures in complex resulting in 97.6% sensitivity, 99.2% specificity and 98.4% accuracy. The analysis of parametric data showed a direct dependency between the degree of lymph nodes involvement and the thickness and width of the tongue tumor. Conclusion. The results of this study indicate a high diagnostic efficacy of MSCT in detecting cancer of different localization in the mouth and on the tongue, determining the area affected and the identification of local metastasis.Цель исследования: определить диагностическую эффективность мультиспиральной компьютерной томографии (МСКТ) в выявлении рака полости рта и языка.Материал и методы. Проанализированы архивные данные результатов МСКТ 243 пациентов в возрасте от 19 до 89 лет, которые были разделены на 2 группы: основная группа – 124 (51,0%) больных с диагнозом рак языка или полости рта и контрольная группа – 119 (49,0%) пациентов, проходивших обследование и лечение в ГБУЗ “ОКД №1 ДЗМ” в период с 2012 по 2016 г. Полученные данные были сопоставлены с данными клинико-инструментального осмотра, а также с данными морфологического заключения.Результаты. Выделены характерные МСКТ-признаки, встречающиеся при раке языка и полости рта: асимметрия анатомических структур, участок уплотнения тканей с плотностными характеристиками в диапазоне +39 …+43 ед.H (min/max −13…+86 ед. H), облитерация межструктурных жировых прослоек, повышение показателей плотности выявленных патологических изменений после внутривенного контрастирования в среднем на 36–47 ед.H (26–68 ед.H), наличие гиподенсной зоны, не накапливающей контрастный препарат, наличие признака дополнительной ткани, наличие признака локального дефекта тканей. Рассчитаны показатели чувствительности, специфичности, точности для каждого признака. Аналогичные расчеты произведены для четырех признаков с наибольшими показателями в совокупности. Чувствительность составила 97,6%, специфичность – 99,2%, точность – 98,4%. Анализ параметрических данных размеров опухолей показал зависимость поражения лимфатических узлов от толщины и ширины опухоли языка.Заключение. Результаты данного исследования свидетельствуют о высокой диагностической эффективности МСКТ в выявлении рака различной локализации в полости рта и на языке, определении площади поражения и выявлении локального метастазирования

Nanoscale engineering of hybrid magnetite–carbon nanofibre materials for magnetic resonance imaging contrast agents

Magnetic nanomaterials show significant promise as contrast agents for magnetic resonance imaging (MRI). We have developed a new highly efficient one-step procedure for the synthesis of magnetically- functionalised hollow carbon nanofibres, where (i) the carbon nanofibres act as both a template and a support for the nucleation and growth of magnetite nanoparticles and (ii) the structural (size, dispersity and morphology) and functional (magnetisation and coercivity) properties of the magnetic nanoparticles formed on nanofibres are strictly controlled by the mass ratio of the magnetite precursor to the nanofibres and the solvent employed during synthesis. We have shown that our magnetite-nanofibre materials are effectively solubilised in water resulting in a stable suspension that has been employed as a ‘‘negative’’ MRI contrast agent with an excellent transverse relaxivity (r2) of (268 13) mM s 1, surpassing current commercial materials and state-of-the-art magnetic nanoscale platforms in performance for MRI contrast at high magnetic fields. The preparation and evaluation of this unique hybrid nanomaterial represents a critical step towards the realisation of a highly efficient ‘‘smart’’ MRI theranostic agent – a material that allows for the combined diagnosis (with MRI), treatment (with magnetic targeting) and follow-up of a disease (with MRI) – currently in high demand for various clinical applications, including stratified nanomedicine