Репозиторий Университета

© 2021 Elsevier B.V. In this work, pristine Cu2O and Au nanoparticle modified Cu2O (Au/Cu2O) spherical nanocomposites were prepared by a simple redox method at room temperature. The as-prepared Cu2O nanospheres with diameters of 150–200 nm show relatively large surface area. The dye removal abilities of the pure Cu2O and the Au/Cu2O nanocomposites were tested by evaluating their adsorption and photocatalytic activities towards different aromatic molecules (e.g., Congo red (CR), Methyl orange (MO), Methyl blue (MB), Rhodamine B (RhB)). The experimental results indicate that the Au/Cu2O nanocomposites exhibit much superior adsorption and photocatalytic properties to the pristine Cu2O nanospheres. Among the catalysts, 1 wt% Au/Cu2O nanocomposite shows the best removal abilities to various dyes. Besides, the removal abilities towards these dyes are quite different from each other. For deep understanding of the adsorption mechanism, molecular dynamics (MD) caculations were conducted to investigate the adsorption energy of the Cu2O spheres by simulating the porous structure and Au modification. The calculation results indicate that CR and MO are chemically adsorbed on the Cu2O materials while the adsorption of MB and RhB are physical adsorption, which are well consistent with the experimental results. This study demonstrates the porous Cu2O based nanocomposites are promising materials with high adsorption and solar light-photocatalytic performance. In the meanwhile, the underlying mechanism on the superior dye removal abilities of Au modified Cu2O nanospheres were systematically discussed.

© 2020 Elsevier B.V. Pesticides can potentially contribute to the development of numerous neurodegenerative diseases. This study evaluates the effects of a six-pesticide mixture at doses around the no-observed-adverse-effectlevels (0 × NOAEL, control) and 0.25, 1 and 5 × NOAEL on behavior of Wistar rats. After 3, 6 and 12 months, rats were observed for neurobehavioral changes using the techniques of elevated plus maze and universal problemchamber, and the experiment was conducted thrice. The 3-month exposure revealed a decrease in the cognitive ability at the dose of 5 × NOAEL, and a dose-dependent research activity and anxiety. The 6-month exposurerevealed non-monotonic effects on the cognitive ability, with a decrease by 0.25 and 5 × NOAEL, as well as non-monotonic effects on anxiety, withan increase by 0.25 and 1 × NOAEL. A decrease was also observed in research activity at 5 × NOAEL. However, the 12-month exposure resulted to an increase in cognitive ability by 0.25 × NOAEL and in anxiety by 1 × NOAEL, as well as to a dose-dependent research activity. Repeating the trial showed that the cognitive ability increased from one trial to another, while the researching activity decreased and the anxiety increased by 0× NOAEL. In the groups exposed to pesticides mixture, the trends were different, showing that the exposure to pesticides combined with repeated trials, also influence the response of the animals. The resultsdemonstrate the occurrence of several dose-dependent behavioral responses, with negative effects occurring at doses that are considered safe. This study provides novel insights about time-dependent mixtures biology, and an important perspective to consider when conducting risk assessments.

© 2020 Elsevier B.V. Pesticides are widely-used chemicals commonly applied in agriculture for the protection of crops from pests. Depending on the class of pesticides, the specific substances may have a specific set of adverse effects on humans, especially in cases of acute poisoning. In past years, evidence regarding sequelae of chronic, low-level exposure has been accumulating. Cognitive impairment and dementia heavily affect a person's quality of life and scientific data has been hinting towards an association between them and antecedent chronic pesticide exposure. Here, we reviewed animal and human studies exploring the association between pesticide exposure, cognition and dementia. Additionally, we present potential mechanisms through which pesticides may act neurotoxically and lead to neurodegeneration. Study designs rarely presented homogeneity and the estimation of the exposure to pesticides has been most frequently performed without measuring the synergic effects and the possible interactions between the toxicants within mixtures, and also overlooking low exposures to environmental toxicants. It is possible that a Real-Life Risk Simulation approach would represent a robust alternative for future studies, so that the safe exposure limits and the net risk that pesticides confer to impaired cognitive function can be examined. Previous studies that evaluated the effect of low dose chronic exposure to mixtures of pesticides and other chemicals intending to simulate real life exposure scenarios showed that hermetic neurobehavioral effects can appear after mixture exposure at doses considered safe for individual compounds and these effects can be exacerbated by a coexistence with specific conditions such as vitamin deficiency. However, there is an overall indication, derived from both epidemiologic and laboratory evidence, supporting an association between exposure to neurotoxic pesticides and cognitive dysfunction, dementia and Alzheimer's disease.

© 2020 Elsevier B.V. Pesticides are widely-used chemicals commonly applied in agriculture for the protection of crops from pests. Depending on the class of pesticides, the specific substances may have a specific set of adverse effects on humans, especially in cases of acute poisoning. In past years, evidence regarding sequelae of chronic, low-level exposure has been accumulating. Cognitive impairment and dementia heavily affect a person's quality of life and scientific data has been hinting towards an association between them and antecedent chronic pesticide exposure. Here, we reviewed animal and human studies exploring the association between pesticide exposure, cognition and dementia. Additionally, we present potential mechanisms through which pesticides may act neurotoxically and lead to neurodegeneration. Study designs rarely presented homogeneity and the estimation of the exposure to pesticides has been most frequently performed without measuring the synergic effects and the possible interactions between the toxicants within mixtures, and also overlooking low exposures to environmental toxicants. It is possible that a Real-Life Risk Simulation approach would represent a robust alternative for future studies, so that the safe exposure limits and the net risk that pesticides confer to impaired cognitive function can be examined. Previous studies that evaluated the effect of low dose chronic exposure to mixtures of pesticides and other chemicals intending to simulate real life exposure scenarios showed that hermetic neurobehavioral effects can appear after mixture exposure at doses considered safe for individual compounds and these effects can be exacerbated by a coexistence with specific conditions such as vitamin deficiency. However, there is an overall indication, derived from both epidemiologic and laboratory evidence, supporting an association between exposure to neurotoxic pesticides and cognitive dysfunction, dementia and Alzheimer's disease.

© 2020 Global-Science Press In this paper we introduce a new mathematical model for the active contraction of cardiac muscle, featuring different thermo-electric and nonlinear conductivity properties. The passive hyperelastic response of the tissue is described by an orthotropic exponential model, whereas the ionic activity dictates active contraction incorporated through the concept of orthotropic active strain. We use a fully incompressible formulation, and the generated strain modifies directly the conductivity mechanisms in the medium through the pull-back transformation. We also investigate the influence of thermo-electric effects in the onset of multiphysics emergent spatiotemporal dynamics, using nonlinear diffusion. It turns out that these ingredients have a key role in reproducing pathological chaotic dynamics such as ventricular fibrillation during inflammatory events, for instance. The specific structure of the governing equations suggests to cast the problem in mixed-primal form and we write it in terms of Kirchhoff stress, displacements, solid pressure, dimensionless electric potential, activation generation, and ionic variables. We also advance a new mixed-primal finite element method for its numerical approximation, and we use it to explore the properties of the model and to assess the importance of coupling terms, by means of a few computational experiments in 3D.

© The Author(s) 2019. Responses of five rotary blood pumps, namely HeartAssist 5, HeartMate II, HeartWare, Sputnik 1, and Sputnik 2, were extensively assessed in six test cases using a mathematical model of the cardiovascular system. Data for the rotary pumps were derived from pressure–flow curves reported in the literature. The test cases were chosen to attempt to cover most common clinical conditions, such as partial or full support or transitions between different levels of ventricular support. The investigated parameters are collected in a table and presented in figures, such as pressure–volume loops, H-Q curves, pump flow, and aortic pressure waveforms. HeartAssist, Sputnik 1, and Sputnik 2 pumps provide comparable level of aortic pressure, pump flow pulsatility PI(QP), and aortic pressure pulsatility PI(AoP) due to the similarity of pressure–flow characteristic curves of these pumps. HeartMate II provides a minimal backflow among other investigated rotary blood pumps due to the maximum pressure head at zero flow. HeartWare provides minimal pulsation of flow, which is confirmed by a flow range from −2 to 7 L/min in case 1. At the same time, the greatest degree of unloading was demonstrated by the HeartWare due to the flatness of the pressure–flow curve shape. The conclusions were made based on the obtained results, including the influence of pressure–flow curve shape on the pump performance and occurrences of adverse events, such as backflow or suction. For example, the increase of the pressure head at zero flow decreases the likelihood of backflow through the pump, and with it, increasing the flow under minimal pressure head increases the likelihood of suction.

© 2019 Elsevier Ltd Sandpiles are ubiquitous in nature and engineering applications but still not fully understood due to the complexity of structures and materials properties. This work presents a systematic study on the piles of Platonic solids using the discrete element method (DEM), mainly focusing on the effect of particle shape on the repose angles and bottom pressure distributions of the piles. Five Platonic particles (tetrahedron, cube, octahedron, dodecahedron, and icosahedron) were discharged to form wedge-shaped piles. It was found that the repose angle did not increase with the decrease of particle sphericity. The pile formed by the cubes had the maximum repose angle and its bottom stress dip phenomena were more significant in terms of dip width and depth than that of other particle piles. The pressure distributions at different heights of the piles were quite similar to those of the whole piles, while the shear stress distributions near the boundaries exhibited different characteristics for the cube piles. The analyses of packing structures in terms of coordination number, radial distribution function, as well as contact types inside the piles were discussed to understand the change of pressure dips. The influence of static friction on the repose angle was more significant and it enhanced the stress dip phenomenon.

AIM: To evaluate the effectiveness of three-dimensional printing application in urology for localized renal cancer treatment using three-dimensional printed soft models. MATERIALS AND METHODS: The study included five patients with kidney tumors. The patients were treated in the Urology Clinic of I.M. Sechenov First Moscow State Medical University from February 2016 to June 2017. Personalized three-dimensional printed models based on computed tomographic images were created. Five surgeons took part in a survey in which the utility of computed tomographic images versus three-dimensional printed models for presurgical planning was compared. A laparoscopic partial nephrectomy training using the developed three-dimensional printed models was performed by the same surgeons in a surgical training box. RESULTS: The patients underwent endoscopic surgery using laparoscopic access. The average time of surgery was 187 min. All the operations were performed with complete renal artery clamping. The average warm ischemia time was 19.5 min and the average blood loss was 170 mL. No conversions to open surgery or radical nephrectomy, and no postoperative complications and deaths were observed. All the surgical margins were negative. The tumors were morphologically identified as renal cell carcinoma in four cases and as oncocytoma in one case. CONCLUSION: The developed three-dimensional printed models allow one to evaluate the pathological anatomy of tumors more effectively. High similarity between three-dimensional models and native kidneys contribute to improvement of surgical skills necessary for partial nephrectomy. Training on the three-dimensional models also allows surgeons to facilitate selection of an optimal surgical tactics for each patient.

© 2018 Elsevier Ltd The space-filling fibrin network is a major part of clots and thrombi formed in blood. Fibrin polymerization starts when fibrinogen, a plasma protein, is proteolytically converted to fibrin, which self-assembles to form double-stranded protofibrils. When reaching a critical length, these intermediate species aggregate laterally to transform into fibers arranged into branched fibrin network. We combined multiscale modeling in silico with atomic force microscopy (AFM) imaging to reconstruct complete atomic models of double-stranded fibrin protofibrils with γ-γ crosslinking, A:a and B:b knob-hole bonds, and αC regions—all important structural determinants not resolved crystallographically. Structures of fibrin oligomers and protofibrils containing up to 19 monomers were successfully validated by quantitative comparison with high-resolution AFM images. We characterized the protofibril twisting, bending, kinking, and reversibility of A:a knob-hole bonds, and calculated hydrodynamic parameters of fibrin oligomers. Atomic structures of protofibrils provide a basis to understand mechanisms of early stages of fibrin polymerization. Zhmurov et al. used 27 relevant crystal structures to computationally reconstruct the full-atomic models of fibrin oligomers and protofibrils, which correlate with high-resolution atomic force microscopy images. The structures contain much valuable information for understanding the early stages of fibrin polymerization.

© 2018, Dynasty Publishing House. All rights reserved. The objective. A comparative study of the dose uniformity, dose reproducibility, imprint areas on a planar simulation model as indicators of dispersion of spray-aerosol pharmaceutical forms of various trademarks for treatment of diseases of the mouth cavity and throat. Materials and methods. As objects of study we selected 10 drugs manufactured in the «aerosol» and «spray» forms. Test for dose uniformity was performed in accordance with articles of the State Pharmacopoeia of the Russian Federation «Aerosols and sprays», comparison of dose reproducibility was performed by comparing average dose mass dispersions according to Fisher. The test for the width of dispersion was performed by imprints obtained of a single release of drugs on filter paper with Dragendorff’s reagent and plates for thin-layer chromatography. Results. All metered-dose sprays successfully passed the test for dose mass uniformity. The test for dose mass reproducibility showed a high enough stability of dosage in all the examined drugs: the percentage error of the average dose mass was at the level 1–3%. The test for dispersion width performed on planar simulation models showed significant differences in the character of drug dispersion. For comparing the width of dispersion we calculated imprint areas from a single-dose release on PSM, which permitted to determine drugs with wide and fine dispersion as the most effective with respect to the way of drug delivery to the focus of inflammation – on the mucous membranes of the throat and mouth cavity. Conclusion. The optimal combination of the examined spray characteristics was found in the spray Tantum® Verde, which permits to recommend it as a drug of choice in paediatrics for local therapy of inflammatory diseases of the throat in children beginning from the age of 3 years.

© 2018 BMSTU. We studied the dependence of the rate of dissolution of d-elements oxides (cobalt and copper oxides) in acidic media with EDTA additives from different factors. Increase in EDTA concentration enhances the cobalt and copper oxides dissolution, while the copper oxide dissolution is inhibited. Within the research we determined the orders by hydrogen ions and EDTA: For cobalt oxide it is 0.5 ± 0.1; for copper oxide it is nH=0,6, and by EDTA it is∼-0.6. The peculiarity of the studied kinetics in EDTA is that the rate of cobalt oxides dissolution passes through a maximum at pH =-1, for copper oxide in the presence of chelating agent EDTA the dissolution rate first decreases, and then it increases at pH from 5 to 8. The activation energy of the process is Ea (H2SO4) = = 70 kJ/mol, Ea (EDTA) = 60 kJ/mol, for copper oxide the activation energy is 73 ± 0.5 kJ/mol. The simulation of the processes showed that the surface particle, which determines the rate of dissolution is eOH+ in mineral acids, and in the chelating agent it is HY.