132 research outputs found
Use of Simulation Methods of Wave Processes for Non-Destructive Testing of Concrete Products of Different Geometrical Size
Theoretical and experimental research of electrical responses under pulsed mechanical excitation of different size concrete products was carried out. Comparison of calculated and experimental data shows very close agreement. The obtained results will help to develop new opportunities to improve the method of non-destructive testing of concrete by creating a bank of calculated electrical responses from products of different geometrical arrangement and elastic response and using them as standard samples for defectiveness evaluation of products according to previously established criteria
RECOMMENDATIONS ON THE WORK WITH AUTHENTIC VIDEO MATERIALS IN FOREIGN LANGUAGE TEACHING
Abstract Video is one of the most appreciated language teaching materials and well-liked by both teachers and learners. It brings variety and flexibility to the language classroom, gives a wide range of communicative situations, makes meaning clearer by providing visual clues (environment, dress, posture, gesture, facial expression, etc.) and communicates with viewers on an emotional as well as a cognitive level. Authentic video motivates learning interest and enthusiasm, improves students' language skills, and enhances comprehension and discussion. This paper discusses benefits, drawbacks, criteria for video selection and strategies to work with video. The authors give examples of exercises that can be used at foreign language classes
Radiation thermal processes in Cr13Mo2NbVB steel - the material of the fuel assembly shell in reactor BN-350 under mechanical tests
Regularities of changes of structural-phase state and mechanical properties of steel 13Mo2NbVB - the material of the fuel assembly shell in reactor BN-350 after various mechanical tests at 350°C are experimentally studied. The formation of microprecipitations FeMo, enriched or depleted with molybdenum was found in the short-time mechanical tests, which is the cause of thermal hardening of irradiated Cr13Mo2NbVB steel and its destruction by the ductile-brittle mechanism. On the basis of long-time creep tests it was shown that the material of the spent fuel assembly shell has sufficient resource for long-time storage in the temperature and force conditions simulating long-time storage of spent nuclear fuel
Features of laboratory parameters in children with multisystem inflammatory syndrome associated with SARS-CoV-2
Multisystem inflammatory syndrome (MIS-C) is a new childhood disease associated with coronavirus SARS-CoV-2 that manifests itself 3–4 weeks after infection. The development of MIS-C is possible, despite the asymptomatic course of coronavirus infection. The pathogenetic features of MIS-C remain unclear. The aim of the study was to investigate the state of peripheral blood parameters in children with multisystem inflammatory syndrome associated with SARS-CoV-2 upon admission to a hospital. Material and methods. We examined 52 children with MIS-C from 1 to 14 years old, hospitalized in Children`s Clinical Hospital No. 3 in Novosibirsk in October–December 2020. Testing for the isolation of SARS-CoV-2 RNA in scrapings from the nasopharynx and oropharynx was carried out using real time PCR (test systems of DNA-Technology, Russia). The presence of specific IgM and IgG antibodies to SARS-CoV-2 in blood serum was determined by ELISA using Vector-Best kits (Russia). Results and discussion. It was noted that SARS-CoV-2 virus RNA was found only in 12.8 % of cases, while specific IgG antibodies in blood serum were detected in 100 % of children. IgM to SARS-CoV-2 antigens were detected in the blood serum only in 53.85 % of children with MIS-C. It has been established that unexpressed leukocytosis was found both in children under the age of 7 and in children of 8–14 years old. However, the leukocytes content in children of the older age group was significantly lower than in children aged 1–7 years. At the same time, in both age groups, some children had extremely low values of the indicator. The causes of severe leukopenia against the background of excessive inflammation remain unclear. Age groups (1–7 and 8–14 years) do not differ statistically significantly in the relative content of lymphocytes and neutrophils. In the study of individual values of the relative content of lymphocytes within the age groups, it was noted that only some children had lymphopenia of varying severity. Conclusions. Against the background of minor leukocytosis in children with MIS-C, upon admission to the hospital, there is a tendency to develop both relative and absolute lymphopenia, regardless of age. The study noted an extremely pronounced variability of individual values of the evaluated peripheral blood parameters, regardless of age, which, with similar clinical symptoms, characterized as MIS-C, requires further study in dynamics, taking into account the initial values of the indicators.There is no pronounced relationship between the leukocytes content and specific IgM antibodies to SARS-CoV-2 antigens in the blood
Thermal effects of carbonated hydroxyapatite modified by glycine and albumin
In this work calcium phosphate powders were obtained by precipitation method from simulated solutions of synovial fluid containing glycine and albumin. X-ray diffraction and IR spectroscopy determined that all samples are single-phase and are presented by carbonate containing hydroxyapatite (CHA). The thermograms of solid phases of CHA were obtained and analyzed; five stages of transformation in the temperature range of 25-1000°C were marked. It is shown that in this temperature range dehydration, decarboxylation and thermal degradation of amino acid and protein connected to the surface of solid phase occur. The tendency of temperature lowering of the decomposition of powders synthesized from a medium containing organic substances was determined. Results demonstrate a direct dependence between the concentration of the amino acid in a model solution and its content in the solid phase
Patterns of calcium oxalate monohydrate crystallization in complex biological systems
The paper presents the features of calcium oxalate crystallization in the presence of additives revealed through experimental modeling. The patterns of phase formation are shown for the Ca{2+} – C[2]O[4]{ 2–} – H[2]O and Ca{2+} – C[2]O[4]{2–} – PO[4]{3–} – H[2]O systems with the components and pH of the saline varying over a wide concentrations range. The effect of additives on crystallization of calcium oxalate monohydrate was investigated. It was found that the ionic strength and magnesium ions are inhibitors, and calcium oxalate and hydroxyapatite crystals are catalysts of calcium oxalate monohydrate crystallization. The basic calcium phosphate (apatite) was found to be most thermodynamically stable, which indicates its special role in kidney stone formation since it is found in virtually all stones
Interactions between Magnetic Nanowires and Living Cells : Uptake, Toxicity and Degradation
We report on the uptake, toxicity and degradation of magnetic nanowires by
NIH/3T3 mouse fibroblasts. Magnetic nanowires of diameters 200 nm and lengths
comprised between 1 {\mu}m and 40 {\mu}m are fabricated by controlled assembly
of iron oxide ({\gamma}-Fe2O3) nanoparticles. Using optical and electron
microscopy, we show that after 24 h incubation the wires are internalized by
the cells and located either in membrane-bound compartments or dispersed in the
cytosol. Using fluorescence microscopy, the membrane-bound compartments were
identified as late endosomal/lysosomal endosomes labeled with lysosomal
associated membrane protein (Lamp1). Toxicity assays evaluating the
mitochondrial activity, cell proliferation and production of reactive oxygen
species show that the wires do not display acute short-term (< 100 h) toxicity
towards the cells. Interestingly, the cells are able to degrade the wires and
to transform them into smaller aggregates, even in short time periods (days).
This degradation is likely to occur as a consequence of the internal structure
of the wires, which is that of a non-covalently bound aggregate. We anticipate
that this degradation should prevent long-term asbestos-like toxicity effects
related to high aspect ratio morphologies and that these wires represent a
promising class of nanomaterials for cell manipulation and microrheology.Comment: 21 pages 12 figure
A chemically modified antibody mediates complete eradication of tumours by selective disruption of tumour blood vessels
These results reinforce the concept that vascular shutdown can induce a curative avalanche of tumour cell death. Immuno-photodynamic therapy may be particularly indicated for squamous cell carcinoma of the skin, which we show to be strongly positive for markers of angiogenesis
Analysing the mechanism of mitochondrial oxidation-induced cell death using a multifunctional iridium(III) photosensitiser
Mitochondrial oxidation-induced cell death, a physiological process triggered by various cancer therapeutics to induce oxidative stress on tumours, has been challenging to investigate owing to the difficulties in generating mitochondria-specific oxidative stress and monitoring mitochondrial responses simultaneously. Accordingly, to the best of our knowledge, the relationship between mitochondrial protein oxidation via oxidative stress and the subsequent cell death-related biological phenomena has not been defined. Here, we developed a multifunctional iridium(III) photosensitiser, Ir-OA, capable of inducing substantial mitochondrial oxidative stress and monitoring the corresponding change in viscosity, polarity, and morphology. Photoactivation of Ir-OA triggers chemical modifications in mitochondrial protein-crosslinking and oxidation (i.e., oxidative phosphorylation complexes and channel and translocase proteins), leading to microenvironment changes, such as increased microviscosity and depolarisation. These changes are strongly related to cell death by inducing mitochondrial swelling with excessive fission and fusion. We suggest a potential mechanism from mitochondrial oxidative stress to cell death based on proteomic analyses and phenomenological observations. Mitochondrial oxidation-induced cell death is an important physiological process activated by cancer therapeutics, but its investigation is challenging. Here, the authors report a multifunctional iridium(III) photosensitiser, Ir-OA, able to induce mitochondrial oxidative stress and monitor the corresponding changes in mitochondrial properties
On the Participation of Photoinduced N–H Bond Fission in Aqueous Adenine at 266 and 220 nm: A Combined Ultrafast Transient Electronic and Vibrational Absorption Spectroscopy Study
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