112 research outputs found

    Diagnosis of Cervical Cancer Using Raman Spectroscopy

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    The aim of the study was to develop a method of detecting cervical cancer using Raman spectroscopy in the examination of biopsy and surgical material. Significant differences in the spectral characteristics between the tissues of the intact cervix and tissues with squamous cell carcinoma of the cervix have been revealed. Intensity of fluorescence in cervical cancer was higher than in intact cervical tissue.     Keywords: cervical cancer, squamous cell carcinoma, diagnosis of cervical cancer, fluorescence in cervical cancer, Raman spectroscopy for the diagnosis of cervical cance

    Reactivity of the Indenyl Radical (C9 H7 ) with Acetylene (C2 H2 ) and Vinylacetylene (C4 H4 ).

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    The reactions of the indenyl radicals with acetylene (C2 H2 ) and vinylacetylene (C4 H4 ) is studied in a hot chemical reactor coupled to synchrotron based vacuum ultraviolet ionization mass spectrometry. These experimental results are combined with theory to reveal that the resonantly stabilized and thermodynamically most stable 1-indenyl radical (C9 H7 . ) is always formed in the pyrolysis of 1-, 2-, 6-, and 7-bromoindenes at 1500 K. The 1-indenyl radical reacts with acetylene yielding 1-ethynylindene plus atomic hydrogen, rather than adding a second acetylene molecule and leading to ring closure and formation of fluorene as observed in other reaction mechanisms such as the hydrogen abstraction acetylene addition or hydrogen abstraction vinylacetylene addition pathways. While this reaction mechanism is analogous to the bimolecular reaction between the phenyl radical (C6 H5 . ) and acetylene forming phenylacetylene (C6 H5 CCH), the 1-indenyl+acetylene→1-ethynylindene+hydrogen reaction is highly endoergic (114 kJ mol-1 ) and slow, contrary to the exoergic (-38 kJ mol-1 ) and faster phenyl+acetylene→phenylacetylene+hydrogen reaction. In a similar manner, no ring closure leading to fluorene formation was observed in the reaction of 1-indenyl radical with vinylacetylene. These experimental results are explained through rate constant calculations based on theoretically derived potential energy surfaces

    THE “CLINOPYROXENE” PALEOGEOTHERM BENEATH THE OBNAZHENNAYA KIMBERLITE PIPE AND THIСKNESS OF LITHOSPHERE UNDER THE KUOYKA FIELD (SIBERIAN CRATON, YAKUTIA)

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    The mantle paleogeotherm under the Obnazhennaya kimberlite pipe (Kuoika field, Siberian craton) was reconstructed using the chemical composition of clinopyroxene xenocrystals and the FITPLOT program. The lithosphere thickness 187–193 km and surface heat flow 41–42 mW/m2 were measured for the Obnazhennaya pipe at the time of kimberlite magmatism in the Mesozoic. The lithosphere thickness was found to be much smaller than that in the central part of the Siberian craton (210–230 km), where Paleozoic diamond-bearing kimberlite pipes-deposits are located. It is however comparable to the highly diamond-bearing Kimberley field in the Kaapvaal craton (South Africa). The absence of diamonds in the pipes of the Kuoika field, but poor diamondiferous Dyanga pipe, might be associated with the more intense metasomatic alteration of the rocks within the lithospheric mantle of this region in the Mesozoic time, as compared to the central part of the Siberian craton in the Middle Paleozoic time

    Development of a molecular-based index for assessing iron status in bloom-forming pennate diatoms

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    Iron availability limits primary productivity in large areas of the world's oceans. Ascertaining the iron status of phytoplankton is essential for understanding the factors regulating their growth and ecology. We developed an incubation-independent, molecular-based approach to assess the iron nutritional status of specific members of the diatom community, initially focusing on the ecologically important pennate diatom Pseudo-nitzschia. Through a comparative transcriptomic approach, we identified two genes that track the iron status of Pseudo-nitzschia with high fidelity. The first gene, ferritin (FTN), encodes for the highly specialized iron storage protein induced under iron-replete conditions. The second gene, ISIP2a, encodes an iron-concentrating protein induced under iron-limiting conditions. In the oceanic diatom Pseudo-nitzschia granii (Hasle) Hasle, transcript abundance of these genes directly relates to changes in iron availability, with increased FTN transcript abundance under iron-replete conditions and increased ISIP2a transcript abundance under iron-limiting conditions. The resulting ISIP2a:FTN transcript ratio reflects the iron status of cells, where a high ratio indicates iron limitation. Field samples collected from iron grow-out microcosm experiments conducted in low iron waters of the Gulf of Alaska and variable iron waters in the California upwelling zone verify the validity of our proposed Pseudo-nitzschia Iron Limitation Index, which can be used to ascertain in situ iron status and further developed for other ecologically important diatoms

    Neoglycolipids Micelle-like Structures as a Basis for Drug Delivery Systems

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    Targeted drug delivery is one of the most promising tasks of nanomedicine, as this is a real way to increase the effectiveness of therapeutic effects against many diseases. In this regard, the development of new inexpensive highly effective stimulating and non-immunogenic drug delivery systems (DDS) is of great importance. In this work new molecular candidates were proposed and studied for the creation of such systems based on the use of new compounds, neoglycolipids. It is shown that these compounds are capable of self-association in aqueous solutions and can serve as potential carriers of drug compounds with targeted delivery determined by their terminal groups (in particular, glycans). The processes of their associates formation and features of their structure are investigated. The results show that these selforganizing nanoscale systems can be used as a basis for developing new drug delivery systems. Keywords: neoglycolipids, micelle-like structures, small-angle X-ray scattering, molecular dynamics simulatio

    DEVELOPMENT OF SPATIAL ANALYSIS TECHNIQUES FOR IDENTIFICATION OF "RISK AREAS" IN CASE OF EXTERNAL THREATS REALIZATION AS REGARDS SANITARY AND EPIDEMIOLOGICAL WELLFARE

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    Objective of the study was to develop the methodology for identification of administratively independent areas under potential risk of “external” epidemiological threat realization, by the example of cholera.Materials and methods. Analysis was conducted using free software package with open source code (QGIS 2.8 and GRASS GIS 7.0) on the basis of the data received from Rosgranitsa and the Federal State Statistics Service. The construction of risk cartogram was performed on the base of Euclidean distance and estimation of nuclear density.Results and conclusions. In accordance with the obtained results, the GIS containing information about the checkpoints on the Russian border, settlements, roads and railway lines was worked out. The method of identification of risk areas due to importation of infectious diseases based on the cholera model has been developed, and the total area of such territories was less than 1 % of the total area of the country. It was found that in some cases the risk area is located at a certain distance from the checkpoint, but the existence of checkpoint does not lead to the formation of risk areas. The developed GIS is available on the geo-information portal of FGHI Rostov-on-Don Research Anti-Plague Institute of Rospotrebnadzor

    The ART-XC telescope on board the SRG observatory

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    ART-XC (Astronomical Roentgen Telescope - X-ray Concentrator) is the hard X-ray instrument with grazing incidence imaging optics on board the Spektr-Roentgen-Gamma (SRG) observatory. The SRG observatory is the flagship astrophysical mission of the Russian Federal Space Program, which was successively launched into orbit around the second Lagrangian point (L2) of the Earth-Sun system with a Proton rocket from the Baikonur cosmodrome on 13 July 2019. The ART-XC telescope will provide the first ever true imaging all-sky survey performed with grazing incidence optics in the 4-30 keV energy band and will obtain the deepest and sharpest map of the sky in the energy range of 4-12 keV. Observations performed during the early calibration and performance verification phase as well as during the on-going all-sky survey that started on 12 Dec. 2019 have demonstrated that the in-flight characteristics of the ART-XC telescope are very close to expectations based on the results of ground calibrations. Upon completion of its 4-year all-sky survey, ART-XC is expected to detect ~5000 sources (~3000 active galactic nuclei, including heavily obscured ones, several hundred clusters of galaxies, ~1000 cataclysmic variables and other Galactic sources), and to provide a high-quality map of the Galactic background emission in the 4-12 keV energy band. ART-XC is also well suited for discovering transient X-ray sources. In this paper, we describe the telescope, results of its ground calibrations, major aspects of the mission, the in-flight performance of ART-XC and first scientific results.Comment: 19 pages, 30 figures, accepted for publication in Astronomy and Astrophysic

    «КЛИНОПИРОКСЕНОВАЯ» ПАЛЕОГЕОТЕРМА ПОД КИМБЕРЛИТОВОЙ ТРУБКОЙ ОБНАЖЕННОЙ: МОЩНОСТЬ ЛИТОСФЕРЫ ПОД КУОЙКСКИМ ПОЛЕМ (СИБИРСКИЙ КРАТОН, ЯКУТИЯ)

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    The mantle paleogeotherm under the Obnazhennaya kimberlite pipe (Kuoika field, Siberian craton) was reconstructed using the chemical composition of clinopyroxene xenocrystals and the FITPLOT program. The lithosphere thickness 187–193 km and surface heat flow 41–42 mW/m2 were measured for the Obnazhennaya pipe at the time of kimberlite magmatism in the Mesozoic. The lithosphere thickness was found to be much smaller than that in the central part of the Siberian craton (210–230 km), where Paleozoic diamond-bearing kimberlite pipes-deposits are located. It is however comparable to the highly diamond-bearing Kimberley field in the Kaapvaal craton (South Africa). The absence of diamonds in the pipes of the Kuoika field, but poor diamondiferous Dyanga pipe, might be associated with the more intense metasomatic alteration of the rocks within the lithospheric mantle of this region in the Mesozoic time, as compared to the central part of the Siberian craton in the Middle Paleozoic time.На основе химического состава ксенокристаллов клинопироксена и с использованием программного пакета FITPLOT была реконструирована мантийная палеогеотерма под кимберлитовой трубкой Обнаженной (Куойкское поле, Сибирский кратон). Значения мощности литосферы и поверхностного теплового потока для трубки Обнаженной на момент кимберлитового магматизма (мезозой) составили 187–193 км и 41–42 мВт/м2. Полученное значение мощности литосферы значительно меньше, чем в центральной части Сибирского кратона, где располагаются алмазоносные кимберлитовые трубки-месторождения среднепалеозойского возраста (210–230 км), однако оно сопоставимо с таковым в районе высокоалмазоносного поля Кимберли (Каапвальский кратон, Южная Африка). Отсутствие алмазов в трубках Куойкского поля, за исключением убогоалмазоносной трубки Дьянга, может быть связано с интенсивным метасоматическим преобразованием пород литосферной мантии данного региона в мезозое по сравнению с центральной частью Сибирского кратона в среднем палеозое

    Взаимосвязь спектроскопических и структурных свойств j-агрегатов индоцианина зеленого

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    Indocyanine green (ICG), when in free form in a liquid, can form stable nanoparticle structures or colloidal solution, while changing its spectroscopic properties. In the work, the aggregation degree and the average size of nanoparticles depending on the concentration of a colloidal solution of indocyanine green (ICG NPs) in the form of J-aggregates were investigated by various methods based on light scattering. The size of nanoparticles is an important parameter from the point of view of clinical application, because the technique of intravenous administration of drugs, in order to avoid microvascular thrombosis and embolism, provides dosage forms with inclusions of individual molecules or their clusters, not exceeding 500 nm diameter. In turn, small nanoparticles less than 30 nm lead to prolonged circulation of the drug in the body with an increased possibility of permeation into cells of healthy tissue. In the course of studies, it was found that an increase in the concentration of ICG NPs in the solution leads to an increase in the average size of spontaneously formed J-aggregates, which, in turn, leads to a decrease in the absorption coefficient in the aggregates. Presumably, this phenomenon, i.e. the established nonlinear dependence of the J-aggregate absorption on its size, can be explained by the formation of absorption centers on the J-aggregate surface in the form of mobile surface molecules. The threshold range of ICG molecule concentration was determined, at which there is a transition from aggregation with an increase in size with a slow addition of ICG J-aggregate molecules in height to a rapid addition in width.Индоцианин зеленый (ICG), находясь в растворе, способен образовывать стабильные структуры наночастиц или коллоидный раствор, изменяя при этом свои спектроскопические свойства. В работе различными методами, основанными на светорассеянии, были исследованы степень агрегации и средний размер наночастиц в зависимости от концентрации коллоидного раствора наночастиц индоцианина зеленого (ICG NPs) в форме J-агрегатов. Размер наночастиц представляет собой важный параметр с точки зрения клинического применения, так как техника внутривенного введения препаратов, с целью избежания тромбозов микрососудов и эмболии, предусматривает лекарственные формы с включениями, в виде отдельных молекул или их кластеров, не превышающими в диаметре 500 нм. С другой стороны, наночастицы размером менее 30 нм длительно циркулируют в организме и могут проникать в клетки здоровой ткани. В ходе исследований, было установлено, что увеличение концентрации ICG NPs в растворе ведет к увеличению среднего размера спонтанно формируемых J-агрегатов, что в свою очередь ведет к уменьшению коэффициента поглощения в агрегатах. Предположительно, нелинейная зависимость поглощения J-агрегата от его размера, может быть объяснен формированием центров поглощения на поверхности J-агрегата в виде подвижных поверхностных молекул. Был определен пороговый диапазон концентрации молекул ICG, при котором происходит переход от агрегации с увеличением размера с медленным прибавлением молекул J-агрегата ICG в высоту, но с быстрым прибавлением в ширину
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