208 research outputs found

    Stable multiple-charged localized optical vortices in cubic-quintic nonlinear media

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    The stability of two-dimensional bright vortex solitons in a media with focusing cubic and defocusing quintic nonlinearities is investigated analytically and numerically. It is proved that above some critical beam powers not only one- and two-charged but also multiple-charged stable vortex solitons do exist. A vortex soliton occurs robust with respect to symmetry-breaking modulational instability in the self-defocusing regime provided that its radial profile becomes flattened, so that a self-trapped wave beam gets a pronounced surface. It is demonstrated that the dynamics of a slightly perturbed stable vortex soliton resembles an oscillation of a liquid stream having a surface tension. Using the idea of sustaining effective surface tension for spatial vortex soliton in a media with competing nonlinearities the explanation of a suppression of the modulational instability is proposed.Comment: 4 pages, 3 figures. Submitted to Journal of Optics A. The proceedings of the workshop NATO ARW, Kiev 2003 Singular Optics 200

    Genetic and morphologic determination of diatom community composition in surface sediments from glacial and thermokarst lakes in the Siberian Arctic

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    Lakes cover large parts of the climatically sensitive Arctic landscape and respond rapidly to environmental change. Arctic lakes have different origins and include the predominant thermokarst lakes, which are small, young and highly dynamic, as well as large, old and stable glacial lakes. Freshwater diatoms dominate the primary producer community in these lakes and can be used to detect biotic responses to climate and environmental change. We used specific diatom metabarcoding on sedimentary DNA, combined with next-generation sequencing and diatom morphology, to assess diatom diversity in five glacial and 15 thermokarst lakes within the easternmost expanse of the Siberian treeline ecotone in Chukotka, Russia. We obtained 163 verified diatom sequence types and identified 176 diatom species morphologically. Although there were large differences in taxonomic assignment using the two approaches, they showed similar high abundances and diversity of Fragilariceae and Aulacoseiraceae. In particular, the genetic approach detected hidden within-lake variations of fragilarioids in glacial lakes and dominance of centric Aulacoseira species, whereas Lindavia ocellata was predominant using morphology. In thermokarst lakes, sequence types and valve counts also detected high diversity of Fragilariaceae, which followed the vegetation gradient along the treeline. Ordination analyses of the genetic data from glacial and thermokarst lakes suggest that concentrations of sulfate, an indicator of the activity of sulfate-reducing microbes under anoxic conditions, and bicarbonate, which relates to surrounding vegetation, have a significant influence on diatom community composition. For thermokarst lakes, we also identified lake depth as an important variable, but sulfate best explains diatom diversity derived from genetic data, whereas bicarbonate best explains the data from valve counts. Higher diatom diversity was detected in glacial lakes, most likely related to greater lake age and different edaphic settings, which gave rise to diversification and endemism. In contrast, small, dynamic thermokarst lakes are inhabited by stress-tolerant fragilarioids and are related to different vegetation types along the treeline ecotone. Our study demonstrated that genetic investigations of lake sediments can be used to interpret climate and environmental responses of diatoms. It also showed how lake type affects diatom diversity, and that such genetic analyses can be used to track diatom community changes under ongoing warming in the Arctic

    The influence of a combined strain-heat treatment on the features of electromagnetic testing of fatigue degradation of quenched constructional steel

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    The possibilities of the magnetic and eddy-current methods for testing fatigue degradation during low-cycle loading of quenched steel 50 (0.51% C) that was subjected to a combined strain-heat treatment according to an optimal regime that included friction treatment with subsequent tempering at T = 350 C, were investigated. It is shown that for steel that was subjected to a combined nanostructuring treatment, the accumulation of a plastic strain under "hard" cyclic loading can be tested using the coercimetric method and values of the residual magnetic induction on the major and minor magnetic-hysteresis loops, values of the maximum and initial magnetic permeabilities, and readings of an eddy-current instrument at a low excitation frequency of the eddy-current transducer. The appearance of surface fatigue cracks can be tested via eddy-current measurements at high frequencies, when the contribution of the crack formation in the hardened layer to the eddy-current characteristics is considerable. Β© 2013 Pleiades Publishing, Ltd

    Eddy-current testing of fatigue degradation upon contact fatigue loading of gas powder laser clad NiCrBSi-Cr 3 C 2 composite coating

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    The possibilities of the eddy-current method for testing the fatigue degradation under contact loading of gas powder laser clad NiCrBSi-Cr 3 C 2 composite coating with 15 wt.% of Cr 3 C 2 additive have been investigated. It is shown that the eddy-current testing of the fatigue degradation under contact loading of the NiCrBSi-15%Cr 3 C 2 composite coating can be performed at high excitation frequencies 72-120 kHz of the eddy-current transducer. At that, the dependences of the eddy-current instrument readings on the number of loading cycles have both downward and upward branches, with the boundary between the branches being 3Γ—10 5 cycles in the given loading conditions. This is caused, on the one hand, by cracking, and, on the other hand, by cohesive spalling and compaction of the composite coating, which affect oppositely the material resistivity and, correspondingly, the eddy-current instrument readings. The downward branch can be used to monitor the processes of crack formation and growth, the upward branch - to monitor the degree of cohesive spalling, while taking into account in the testing methodology an ambiguous character of the dependences of the eddy-current instrument readings on the number of loading cycles. Β© 2017 Author(s)

    Pharmacoeconomic analysis of the use of first- and second-line drugs in the treatment of multiple sclerosis

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    Objective: to make a pharmacoeconomic comparison of the administration of first- and second-line drugs in the treatment of multiple sclerosis through cost, cost-effectiveness, and budget impact analyses using the 2015 state prices.Material and methods. A pharmacoeconomic analysis was carried out on the basis of the data available in the literature on trials of the effects of the drugs on the rates of exacerbations and disability. On calculating, the authors took into account the current standards for the out- and inpatient management of patients with this nosological entity in accordance with the compulsory health insurance (CHI) program; prices forΒ state drug purchases in March 2015; prices for medical services in compliance with the CHI standards in Moscow in 2015; the average sizes of minimum wage, salary, and disability grants with consideration for a discount rate of 3%. The cost-effectiveness and budget impact analyses were performed for intramuscular interferon (INF)-Ξ²1a (avonex, 30 ΞΌg), subcutaneous INF-Ξ²1a (rebif, 44 ΞΌg), subcutaneous INF-Ξ²1b (ronbetal, 8,000,000 IU), subcutaneous INF-Ξ²1b (betaferon, 9,600,000 IU), subcutaneous glatiramer acetate (copaxone, 20 mg), intravenous natalizumab (tyzabri, 300 mg), and oral fingolimod (gilenya, 0.5 mg).Results and discussion. The second-line drug tyzabri outperforms the first-line agents for cost-effectiveness. The first-line drugs betaferon and copaxone is slightly exceeded in this indicator by tyzabri; the other both first- and second-line agents compared are all the more inferior in this indicator. The budget impact analysis has shown that the cost of the second-line drugs was higher than that of the first-line ones

    Π­Π½Π΄ΠΎΠΏΡ€ΠΎΡ‚Π΅Π· Π½ΠΈΠΆΠ½Π΅ΠΉ Ρ‡Π΅Π»ΡŽΡΡ‚ΠΈ с ΠΎΠΏΠΎΡ€Π½Ρ‹ΠΌΠΈ Π·ΠΎΠ½Π°ΠΌΠΈ ΠΊΠ°ΠΊ искусствСнный ΠΎΡ€Π³Π°Π½

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    Mandibular reconstruction after partial or complete resection is a prerequisite for restoring normal facial aesthetics, articulation and chewing function. We present a clinical case of lower jaw reconstruction in a female patient with acquired extensive bone defect while taking pervitin and desomorphine. Detailed descriptions of the stages of planning and performing surgery, manufacture of an individual endoprosthesis, as well as preoperative preparation of the patient are presented. Clinical and radiological data in the postoperative period were analyzed and an objective assessment of the effectiveness of the technique was given. Adequate restoration of the main functions of the lost organ was achieved thanks to the use of an individual titanium mandibular endoprosthesis with integrated dental implants and a full-arch denture.РСконструкция Π½ΠΈΠΆΠ½Π΅ΠΉ Ρ‡Π΅Π»ΡŽΡΡ‚ΠΈ послС Π΅Π΅ частичной ΠΈΠ»ΠΈ ΠΏΠΎΠ»Π½ΠΎΠΉ Ρ€Π΅Π·Π΅ΠΊΡ†ΠΈΠΈ являСтся Π½Π΅ΠΎΠ±Ρ…ΠΎΠ΄ΠΈΠΌΡ‹ΠΌ условиСм для восстановлСния Π½ΠΎΡ€ΠΌΠ°Π»ΡŒΠ½ΠΎΠΉ эстСтики Π»ΠΈΡ†Π°, артикуляции ΠΈ ΠΆΠ΅Π²Π°Ρ‚Π΅Π»ΡŒΠ½ΠΎΠΉ Ρ„ΡƒΠ½ΠΊΡ†ΠΈΠΈ. Π’ Π΄Π°Π½Π½ΠΎΠΉ ΠΏΡƒΠ±Π»ΠΈΠΊΠ°Ρ†ΠΈΠΈ прСдставлСн клиничСский случай рСконструкции Π½ΠΈΠΆΠ½Π΅ΠΉ Ρ‡Π΅Π»ΡŽΡΡ‚ΠΈ Ρƒ ΠΏΠ°Ρ†ΠΈΠ΅Π½Ρ‚ΠΊΠΈ с ΠΏΡ€ΠΈΠΎΠ±Ρ€Π΅Ρ‚Π΅Π½Π½Ρ‹ΠΌ ΠΎΠ±ΡˆΠΈΡ€Π½Ρ‹ΠΌ Π΄Π΅Ρ„Π΅ΠΊΡ‚ΠΎΠΌ кости Π½Π° Ρ„ΠΎΠ½Π΅ ΠΏΡ€ΠΈΠ΅ΠΌΠ° наркотичСских вСщСств Π½Π° основС ΠΏΠ΅Ρ€Π²ΠΈΡ‚ΠΈΠ½Π° ΠΈ Π΄Π΅Π·ΠΎΠΌΠΎΡ€Ρ„ΠΈΠ½Π°. ΠŸΡ€ΠΈΠ²Π΅Π΄Π΅Π½ΠΎ Π΄Π΅Ρ‚Π°Π»ΡŒΠ½ΠΎΠ΅ описаниС этапов планирования ΠΈ провСдСния ΠΎΠΏΠ΅Ρ€Π°Ρ‚ΠΈΠ²Π½ΠΎΠ³ΠΎ Π²ΠΌΠ΅ΡˆΠ°Ρ‚Π΅Π»ΡŒΡΡ‚Π²Π°, изготовлСния ΠΈΠ½Π΄ΠΈΠ²ΠΈΠ΄ΡƒΠ°Π»ΡŒΠ½ΠΎΠ³ΠΎ эндопротСза, Π° Ρ‚Π°ΠΊΠΆΠ΅ ΠΏΡ€Π΅Π΄ΠΎΠΏΠ΅Ρ€Π°Ρ†ΠΈΠΎΠ½Π½ΠΎΠΉ ΠΏΠΎΠ΄Π³ΠΎΡ‚ΠΎΠ²ΠΊΠΈ ΠΏΠ°Ρ†ΠΈΠ΅Π½Ρ‚Π°. ΠŸΡ€ΠΎΠ°Π½Π°Π»ΠΈΠ·ΠΈΡ€ΠΎΠ²Π°Π½Ρ‹ клиничСскиС ΠΈ рСнтгСнологичСскиС Π΄Π°Π½Π½Ρ‹Π΅ Π² послСопСрационном ΠΏΠ΅Ρ€ΠΈΠΎΠ΄Π΅, Π΄Π°Π½Π° ΠΎΠ±ΡŠΠ΅ΠΊΡ‚ΠΈΠ²Π½Π°Ρ ΠΎΡ†Π΅Π½ΠΊΠ° эффСктивности ΠΌΠ΅Ρ‚ΠΎΠ΄ΠΈΠΊΠΈ. Π—Π° счСт примСнСния ΠΈΠ½Π΄ΠΈΠ²ΠΈΠ΄ΡƒΠ°Π»ΡŒΠ½ΠΎΠ³ΠΎ Ρ‚ΠΈΡ‚Π°Π½ΠΎΠ²ΠΎΠ³ΠΎ эндопротСза Π½ΠΈΠΆΠ½Π΅ΠΉ Ρ‡Π΅Π»ΡŽΡΡ‚ΠΈ с Π²ΠΊΠ»ΡŽΡ‡Π΅Π½Π½Ρ‹ΠΌΠΈ Π΄Π΅Π½Ρ‚Π°Π»ΡŒΠ½Ρ‹ΠΌΠΈ ΠΈΠΌΠΏΠ»Π°Π½Ρ‚Π°Ρ‚Π°ΠΌΠΈ ΠΈ изготовлСния ортопСдичСской конструкции достигнуто Π°Π΄Π΅ΠΊΠ²Π°Ρ‚Π½ΠΎΠ΅ восстановлСниС основных Ρ„ΡƒΠ½ΠΊΡ†ΠΈΠΉ ΡƒΡ‚Ρ€Π°Ρ‡Π΅Π½Π½ΠΎΠ³ΠΎ ΠΎΡ€Π³Π°Π½Π°

    Modulational instability, solitons and beam propagation in spatially nonlocal nonlinear media

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    We present an overview of recent advances in the understanding of optical beams in nonlinear media with a spatially nonlocal nonlinear response. We discuss the impact of nonlocality on the modulational instability of plane waves, the collapse of finite-size beams, and the formation and interaction of spatial solitons.Comment: Review article, will be published in Journal of Optics B, special issue on Optical Solitons, 6 figure

    Delayed behavioral and neurochemical effects of anti-glutamate antibodies in aging C57BL/6 mice

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    We analyzed delayed effect of intranasal administration of anti-glutamate antibodies on mnestic function and tissue concentrations of neurotransmitters in the hippocampus and prefrontal cortex in aging C57BL/6 mice. It was found that after 14-day administration of anti-glutamate antibodies, improvement of the passive avoidance conditioning persisted for 7 days after the treatment was discontinued. In 7 days after discontinuation of treatment, increased content of dopamine and its metabolites as well as aspartic acid and taurine was observed in the hippocampus of mice treated with anti-glutamate antibodies. In the prefrontal cortex, administration of anti-glutamate antibodies had no effect on the levels of neurotransmitters, but increased the concentration of glutamate

    Safety of adaptive ventilation modes ISV and PSV when weaning the patient from a respirator

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    Introduction. Currently there are no reports or recommendations concerning the ventilator weaning process. Appliance of the intellectual adaptive ventilation mode (iSV) represented in indigenous Russian unit ALV ZISLINE МV200 К 1.19 (Β«TritonΒ» Yekaterinburg) is highly potential. It provides minute ventilation target volume regardless of spontaneous patient’s respiratory activity and controls the pressure-support ventilation level (PSV) after each ventilatory cycle. Object was to increase safety of a patient’s spontaneous breathing adaptation period after longtime artificial lung ventilationЦСль Ρ€Π°Π±ΠΎΡ‚Ρ‹ β€” ΠΎΡ†Π΅Π½ΠΈΡ‚ΡŒ Π±Π΅Π·ΠΎΠΏΠ°ΡΠ½ΠΎΡΡ‚ΡŒ Ρ€Π΅ΠΆΠΈΠΌΠΎΠ² примСнСния Π²ΡΠΏΠΎΠΌΠΎΠ³Π°Ρ‚Π΅Π»ΡŒΠ½ΠΎΠΉ вСнтиляции PSV ΠΈ iSV Π² ΠΏΠ΅Ρ€ΠΈΠΎΠ΄ Π°Π΄Π°ΠΏΡ‚Π°Ρ†ΠΈΠΈ ΠΏΠ°Ρ†ΠΈΠ΅Π½Ρ‚Π° ОРИВ ΠΊ спонтанному Π΄Ρ‹Ρ…Π°Π½ΠΈΡŽ послС Π΄Π»ΠΈΡ‚Π΅Π»ΡŒΠ½ΠΎΠΉ Π˜Π’Π›
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