2,443 research outputs found
Issues in the study of utero-placental blood flow in severe gestosis
The complications of pregnancy, gestosis particularly, are still important aspects on the modern stage of development of obstetrics, as it influences on development of maternal and perinatal morbidity and mortality. One hundred and twenty-five patients with severe gestosis were studied. The conditions of myometrium, endometrium, placenta, umbilical chord as well as erythrocytes of maternal blood were explored with help of atomic power microscopy, light microscopy as well as electron microscop
Past and future of the Arctic sea ice in High-Resolution Model Intercomparison Project (HighResMIP) climate models
We examine the past and projected changes in Arctic sea ice properties in six climate models participating in the High-Resolution Model Intercomparison Project (HighResMIP) in the Coupled Model Intercomparison Project Phase 6 (CMIP6). Within HighResMIP, each of the experiments is run using a reference resolution configuration (consistent with typical CMIP6 runs) and using higher-resolution configurations. The role of horizontal grid resolution in both the atmosphere model component and the ocean model component in reproducing past and future changes in the Arctic sea ice cover is analysed. Model outputs from the coupled historical (hist-1950) and future (highres-future) runs are used to describe the multi-model, multi-resolution representation of the Arctic sea ice and to evaluate the systematic differences (if any) that resolution enhancement causes. Our results indicate that there is not a strong relationship between the representation of sea ice cover and the ocean/atmosphere grids; the impact of horizontal resolution depends rather on the sea ice characteristic examined and the model used. However, the refinement of the ocean grid has a more prominent effect compared to the refinement of the atmospheric one, with eddy-permitting ocean configurations generally providing more realistic representations of sea ice area and sea ice edges. All models project substantial sea ice shrinking: the Arctic loses nearly 95 % of sea ice volume from 1950 to 2050. The model selection based on historical performance potentially improves the accuracy of the model projections and predicts that the Arctic will turn ice-free as early as 2047. Along with the overall sea ice loss, changes in the spatial structure of the total sea ice and its partition in ice classes are noticed: the marginal ice zone (MIZ) will dominate the ice cover by 2050, suggesting a shift to a new sea ice regime much closer to the current Antarctic sea ice conditions. The MIZ-dominated Arctic might drive development and modification of model physics and parameterizations in the new generation of general circulation models (GCMs).</p
Assessing the representation of Arctic sea ice and the marginal ice zone in ocean–sea ice reanalyses
The recent development of data-assimilating reanalyses of the global ocean and sea ice enables a better understanding of the polar region dynamics and provides gridded descriptions of sea ice variables without temporal and spatial gaps. Here, we study the spatiotemporal variability of the Arctic sea ice area and thickness using the Global ocean Reanalysis Ensemble Product (GREP) produced and disseminated by the Copernicus Marine Service (CMS). GREP is compared and validated against the state-of-the-art regional reanalyses PIOMAS and TOPAZ, as well as observational datasets of sea ice concentration and thickness for the period 1993–2020. Our analysis presents pan-Arctic metrics but also emphasizes the different responses of ice classes, the marginal ice zone (MIZ), and pack ice to climate changes.  This aspect is of primary importance since the MIZ accounts for an increasing percentage of the summer sea ice as a consequence of the Arctic warming and sea ice extent retreat, among other processes. Our results show that GREP provides reliable estimates of present-day and recent-past Arctic sea ice states and that the seasonal to interannual variability and linear trends in the MIZ area are properly reproduced, with the ensemble spread often being as broad as the uncertainty of the observational dataset. The analysis is complemented by an assessment of the average MIZ latitude and its northward migration in recent years, a further indicator of the Arctic sea ice decline. There is substantial agreement between GREP and reference datasets in the summer. Overall, GREP is an adequate tool for gaining an improved understanding of the Arctic sea ice, also in light of the expected warming and the Arctic transition to ice-free summers.</p
Migration of Russian researchers: analysis based on a scientometric approach
The article proposes a new method for studying academic mobility, which, based on the author's publications, builds a history of his affiliation changing places, cities and countries of residence. This method was applied for studying academic mobility for publications of Russian researchers indexed in the Scopus database in 2000–2019. The results demonstrate that the depressive process of brain drain in Russia in 2015 was transformed into a process of brain circulation, when the number of immigrants in science became comparable to that of emigrants. In 2007–2011, most of the scientists left for the USA, Germany and other European countries. In 2015–2016, the number of scientists, who came to Russia from the CIS countries, approximately doubled, which compensated for the outflow in other areas. The intra-Russian migration of researchers is 76% related to Moscow, where more researchers come than leave the regions. In addition to the capital, St. Petersburg stands out, where there is a steady influx of researchers from other regions, which compensates for those leaving for the capital, and the Novosibirsk Region, which is the center of migration processes in the Ural and Siberian federal districts and the largest donor for other regions. At the same time, in all three regions, the outflow of researchers abroad in 2012–2016 significantly exceeded the inflow from other regions. In the rest of the Russian Federation, academic mobility in the indicated years was markedly less pronounced
Diversity of Prokaryotes in Planktonic Communities of Saline Sol-Iletsk lakes (Orenburg Oblast, Russia)
© 2018, Pleiades Publishing, Ltd. Prokaryotic diversity was studied in the planktonic communities of six Sol-Iletsk lakes (Orenburg oblast, Russia) varying in salinity level using the Illumina technology of high-throughput sequencing. The extremely halophilic archaea of the phyla Euryarchaeota and Nanohaloarchaeota, as well as the bacterial phylum Bacteroidetes predominated in the communities of lakes with salinity of 285–300‰. Representatives of the phyla Bacteroidetes and Actinobacteria, as well as of the class Gammaproteobacteria were predominant in the lakes with salinity 110−180‰. A bloom of Cyanobacteria was observed in Bol’shoe Gorodskoe Lake (10‰ salinity). The dominant OTUs in the lakes with high salinity were represented by archaea Halonotius sp., uncultured Nanohaloarchaea, and bacteria Salinibacter sp. In the lakes with medium salinity level the dominants included gammaproteobacteria Spiribacter sp., alphaproteobacteria Roseovarius sp., flavobacteria Psychroflexus sp., unidentified archaea of the family Haloferacaceae, actinobacteria Pontimonas sp. and Rhodoluna sp. In the lake with low salinity level cyanobacteria of the genus Planktothrix were predominant. Effect of salinity on prokaryotic taxonomic richness, composition, and diversity in planktonic communities of the studied lakes was demonstrated
Analysis of <i>cis</i>-isomer-enriched dihydroquercetin sample by 1D and 2D NMR spectroscopy
Introduction. The structure of dihydroquercetin (DHQ) is characterized by two chiral centers at positions 2 and 3 of the benzopyran cycle, resulting in possible diastereomers: trans- and cis-isomers. Therefore, the development of methods for qualitative and quantitative control of DHQ diastereomers in analyzed samples is essential for patient safety management. Nuclear magnetic resonance (NMR) spectroscopy is one of the physicochemical methods that can be used for this purpose.Aim. The study objective was to accumulate the analytical and structural characteristics of cis-DHQ by NMR spectroscopy of the spheroidal form of this flavonoid (DHQs).Materials and Methods. 1D 1H, 1H,1H-COSY, 1H,1H-NOESY, and 1H,13C-HSQC NMR spectra were acquired at 298 K on an 800 MHz NMR spectrometer equipped with a TXI triple resonance probe. The number of scans was 32. The mixing time in the NOESY experiment was 400 ms. The 1H and 13C were analyzed using CcpNmr software. The dihedral angles were calculated by applying the Karplus equation.Results and discussion. In trans-DHQ, the chemical shift values for H2 and H3 are 4.93 ppm and 4.52 ppm, respectively, and in cis-DHQ they are 5.31 ppm and 4.20 ppm, respectively. The spin-spin coupling constants between H2 and H3 of trans- and cis-DHQ are 12.00 Hz and 2.40 Hz, respectively. Thus, the dihedral angles for the trans- and cis-isomers are 154° and 64°, respectively. We found that DHQs contains 12.5 % of the cis-isomer.Conclusion. Our experiments confirmed that NMR spectroscopy can discriminate between trans- and cis-DHQ based on the chemical shift values for the cross-peaks of H2 and H3. The second major finding was that this method can be considered as a more selective quantitative analysis than HPLC with UV detection without reference. One of the most important results of this study for drug development is the updated information on the structural parameters of DHQ diastereomers in the liquid phase
Impact of Smoking and Thiocyanate on Perchlorate and Thyroid Hormone Associations in the 2001–2002 National Health and Nutrition Examination Survey
Insights in wound healing properties of water-soluble composition of dihydroquercetin and L-lysine
This study focuses on implementing a composition of the natural flavonoid dihydroquercetin (DHQ) with L-lysine in the treatment of thermal burns. The wound-healing activity of DHQ is well-known. The addition of amino acid to the composition increases the water solubility of the flavonoids, providing an opportunity to develop a spray dosage form. The research involved 60 male Wistar rats divided into five treatment groups. Sea buck oil served as a positive control. On day 14, the composition treatment group showed significant progress in wound healing, being 9.6 ± 2.0% ahead of the other groups in absolute terms. On day 35, treatment with the composition resulted in a significant decrease in relative wound area to 1.9 ± 0.9%, while in the negative and positive control groups, it was 10.7 ± 7.8% and 8.4 ± 4.9%, respectively. At the same time, the epidermal and dermal layers were found to be clearly distinguished in the composition treatment according to histological analysis. Numerous collagen fibres were clearly visible, and the active process of keloid scar formation was observed. An additive effect of the combined use of DHQ and L-lysine was observed (F = 0.21, p = 0.649). A natural next step is to develop the dosage form for the DHQ-L-lysine composition
Influence of Tempering Parameters on The Structure and Hardness of Medium-Carbon Microalloyed Steel
Целью настоящей работы являлось исследование микроструктуры и твердости конструкционной стали 38Г2Ф после закалки и высокотемпературному отпуска с различным временем изотермической выдержки. Скорость нагрева закаленных образцов исследуемой стали до температуры отпуска составляла 0,3 °С/с и 90 °С/с. Методами структурного, дюрометрического, дилатометрического, анализа изучены процессы, происходящие при отпуске мартенсита.The aim of this work was to study the microstructure and hardness of structural steel 38G2F after quenching and high-temperature tempering with different isothermal holding times. The heating rate of quenched samples of the studied steel to the tempering temperature was 0.3 °C/s and 90 °C/s. The processes occurring during martensite tempering were studied dy means of structural, durometric, and dilatometric analysis methods.Работа выполнена при финансовой поддержке Министерства науки и высшего образования Российской Федерации (Программа развития Уральского федерального университета в рамках программы «Приоритет 2030»). Испытания проведены с использованием оборудования ЦКП УрФУ
LYMPHOCYTE PHENOTYPE IN PATIENTS WITH SKIN MELANOMA AFTER IMMUNOTHERAPY OF ACTIVATED LYMPHOCYTES
The major medical problem in the treatment of skin melanoma is improvement methods of treatment, increasing their effectiveness and safety. In this study, adoptive immunotherapy, using lymphocytes activated in vitro, was performed in 15 patients with metastatic melanoma. Evaluated the phenotype of peripheral blood lymphocytes and activation markers (HLA-DR, CD25, CD314, CD38, CD69) before and 3-4 weeks after immunotherapy. It is shown that for these patients is characterized by increasing the number of CD25+ and Treg lymphocytes in the bloodstream, which has not changed after immunotherapy. Adoptive immunotherapy in combination with chemotherapy resulted in a decrease of absolute number of lymphocyte, B- and T-lymphocytes, T helper cells, NKT-cells, CD314+ lymphocytes, CD38+ lymphocytes and immature T-lymphocytes (CD3+CD38+) (р < 0,05). However, there was a positive dynamic to increase the percentage of NK-cells to 32% and CD69+NK-cells to 21% and significant increase in expression of HLA-DR on all lymphocytes (p < 0.05). Adoptive immunotherapy characterized by the absence of side effects and can be recommended as accompanying to basic radiation and chemotherapy
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