1,601 research outputs found

    Nonlinear response of superparamagnets with finite damping: an analytical approach

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    The strongly damping-dependent nonlinear dynamical response of classical superparamagnets is investigated by means of an analytical approach. Using rigorous balance equations for the spin occupation numbers a simple approximate expression is derived for the nonlinear susceptibility. The results are in good agreement with those obtained from the exact (continued-fraction) solution of the Fokker-Planck equation. The formula obtained could be of assistance in the modelling of the experimental data and the determination of the damping coefficient in superparamagnets.Comment: 7 PR pages, 2 figure

    Co-application of Difenoconazole with Thymol Results in Suppression of a Parastagonospora Nodorum Mutant Strain Resistant to this Triazole

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    Results of in vitro study of thymol, a natural chemosensitizer, as a potential agent for overcoming of difenoconazole resistance of Parastagonospora nodorum causing glume and leaf blotch of wheat are first reported. The level of difenoconazole resistance of a natural mutant PNm1 strain with low sensitivity to the Dividend fungicide (a.i. difenoconazole) was determined by the cultivation of this isolate on potato dextrose agar in the presence of the fungicide at sub-lethal and lethal (in relation to the initial fungicide-sensitive strain) concentrations. A principal possibility of the thymol use to overcome resistance of P. nodorum to DMI (demethylation inhibitors) fungicides is shown. Co-application of this compound with Dividend SC, 3 % resulted in a significant reduction of resistance of the mutant strain and enhancement of its sensitivity to difenoconazole up to the level corresponding to the initial non-resistant isolate

    Outlier detection and classification in sensor data streams for proactive decision support systems

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    A paper has a deal with the problem of quality assessment in sensor data streams accumulated by proactive decision support systems. The new problem is stated where outliers need to be detected and to be classified according to their nature of origin. There are two types of outliers defined; the first type is about misoperations of a system and the second type is caused by changes in the observed system behavior due to inner and external influences. The proposed method is based on the data-driven forecast approach to predict the values in the incoming data stream at the expected time. This method includes the forecasting model and the clustering model. The forecasting model predicts a value in the incoming data stream at the expected time to find the deviation between a real observed value and a predicted one. The clustering method is used for taxonomic classification of outliers. Constructive neural networks models (CoNNS) and evolving connectionists systems (ECS) are used for prediction of sensors data. There are two real world tasks are used as case studies. The maximal values of accuracy are 0.992 and 0.974, and F1 scores are 0.967 and 0.938, respectively, for the first and the second tasks. The conclusion contains findings how to apply the proposed method in proactive decision support systems

    Blood Lipoproteins under the Action of Exogenous Sex Steroids in the Postresuscitation Period

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    Objective: to study the effect of reproductive hormones on the blood lipoprotein spectrum in the postresuscitation period after cardiac arrest. Materials and methods. Experiments were carried out on 66 mature albino rats of either sex weighing 200—250 g. Ten-minute cardiac arrest was induced by intrathoracic ligation of the vascular bundle. At 30 min after resuscitation, 49 animals were intramuscularly injected placebo and 17 animals were administered gyn-odian depot (Schering, Germany). The investigators measured the plasma concentrations of progesterone, 17-OH progesterone, androstenedione, dehydroepiandrosterone sulfate, testosterone, estradiol, and estriol, as well as the levels of triglycerides, total, and high-density lipoprotein (HDL), low-density lipoprotein (LDL), and very low-density lipoprotein (VLDL) cholesterols. Blood was sampled on days 2 and 16 in the absence of therapy and on day 16 of sex steroid therapy. Results. By day 2 postresuscitation, the progesterone/estradiol ratio increased by approximately 1.8 times in males and females. Despite the fact that there were no changes in the concentrations of triglycerides, VLDL and HDL cholesterols in both males and females at that time, but the level of LDL cholesterol increased. Gender-related differences in the LDL spectrum by day 2 postresuscitation remained only in the levels of LDL cholesterol. Despite the normalization of progesterone levels, the concentrations of triglycerides and VLDL cholesterol decreased by day 16 of the postresuscitative period in the absence of therapy. There were no gender-related differences in the lipoprotein spectrum at this stage. The exogenous estradiol in combination with dehydroepiandrosterone caused a significant increase in the concentration of HLD cholesterol and a reduction in that of VLDL cholesterol in males and females both. Conclusion. Under gynodian action, the lipid spectrum was indicative of the exogenous estra-diol and dehydroepiandrosterone sulfate activation of the receptor transport of polyunsaturated fatty acids to the cells and that of reverse cholesterol outflow from the cell membranes in the resuscitated animals. Key words: cardiac arrest, reproductive steroids, blood lipoproteins, gynodian, postresuscitation period

    Probe microscopy in the study of the surface of aluminum alloys

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    The work was supported by the Grant of the RNF 14-19-01033-P (study of topography and elemental composition of the surface) and the State Task (№ State registration AAAA-A17-117021310379-5 - study of electrical properties of the surface). The authors are grateful to N.A. Belov (MISiS) for providing samples

    Late intraocular lens dislocation. Retrospective study

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    Purpose. To analyze the frequency, terms and risk factors of late IOL dislocation.Material and methods. A retrospective cohort study was conducted based on archival data of 70 787 cases of the senile cataracts phacoemulsifications performed in 2002–2019 years. Statistical processing of the results and Kaplan–Meier analysis were performed using the SPSS 11.0 program (STATA).Results. 320 patients in the study group were treated for late IOL dislocation at various postoperative periods. The average age of the patients was 76.2±12.5 years at the moment of reconstruction procedure. The periods from the moment of IOL implantation to its dislocation varied from 4 months to 17.58 years, the average term was 6.95±3.67 years. IOL reposition was performed in 272 cases (85.0%) and IOL change – in 48 cases (15.0%). The leading risk factor was pseudoexfoliation syndrome detected in 239 patients (74.7%). Among other factors there was high myopia (72 patients; 22.5%), in 78 cases there were the surgery procedures between cataract surgery and IOL dislocation: glaucoma surgeries – 27 cases (8.4%), vitreal surgeries – 9 cases (2.8%), laser discission of secondary cataract – 42 cases (13.1%). The cumulative 5-, 10-, 15-, and 18- year risk of late IOL dislocation was estimated using Kaplan–Meier analysis.Conclusion. The dynamics of the number of reconstructive operations at late IOL dislocations has a tendency to increase. The average term from the IOL implantation to its dislocation was 6,95±3,67 years. The leading risk factor was pseudoexfoliation syndrome. The cumulative 5-, 10-, 15-, and 18-year risk of late IOL dislocation was 0.2; 0.7; 1.15; and 1.4%, respectively

    Methods of probe microscopy in the study of topography and elastic properties of cold-resistant elastomers

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    The work was carried out under the financial support of the Russian Science Fund, grant 14-29-00198-П(sample preparation and scanning electron microscopy) and the Federal Agency of Scientific Organizations - Agreement No 007-ГЗ/Ч3363/26 (scanning probe microscopy)

    Effect of Pr3+/Pr4+ ratio on the oxygen ion transport and thermomechanical properties of the pyrochlore and fluorite phases in the ZrO2-Pr2O3 system

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    This paper examines the effect of the Pr3+/Pr4+ ratio on the mechanism of ionic and electronic transport in the (Pr2?xZrx)Zr2O7+x/2 (x = 0.15), Pr2Zr2O7, and Pr2(Zr2?xPrx)O7?x/2 (x = 0.1) pyrochlore phases and Pr3ZrOx with the fluorite structure and on the behavior of their thermal expansion coefficient (TEC). The solid solutions were prepared through coprecipitation followed by firing of the green compacts in air at a high temperature of 1550 ?C for 4 h. The Pr3+/Pr4+ ratio was shown to decrease in going from the (Pr2?xZrx)Zr2O7+x/2 (x = 0.15), Pr2Zr2O7, and Pr2(Zr2?xPrx)O7?x/2 (x = 0.1) pyrochlores to the Pr3ZrOx fluorite, leading to changes in the conductivity type from mixed (ionic?electronic) to electronic and in the color of the materials from beige to black and to an anomalous deviation of the TEC from linearity in fluorite Pr3ZrOx, i.e. at the highest Pr4+ content. According to impedance spectroscopy results, (Pr2?xZrx)Zr2O7+x/2 with x = 0.15 has purely oxide-ion conductivity (3 ? 10?3 S/cm at 1000 ?C) in a wide range of oxygen partial pressures: from 10?10 to 102 Pa. With increasing Pr content, p-type electronic conductivity becomes significant, reaching a maximum in fluorite Pr3ZrOx: ?0.5 S/cm at 1000 ?C. According to XPS data, all pyrochlore samples (Pr2?xZrx)Zr2O7+x/2 (x = 0.15), Pr2Zr2O7 and Pr2(Zr2?xPrx)O7?x/2 (x = 0.1) contain only Pr3+ at room temperature, whereas Pr3ZrOx contains both Pr3+ and Pr4+. The considerable deviation of the TEC of Pr3ZrOx from linearity above 500 ?C is due to partial reduction of Pr4+. The reduction process Pr4+ + e? ? Pr3+ followed by oxygen release in the range 500?1100 ?C has been identified in Pr3ZrOx by thermal analysis and mass spectrometry in a He atmosphere.371C-9F16-EBDE | Eduarda GomesN/

    Direct multiplex imaging and optogenetics of Rho GTPases enabled by near-infrared FRET

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    Direct visualization and light control of several cellular processes is a challenge, owing to the spectral overlap of available genetically encoded probes. Here we report the most red-shifted monomeric near-infrared (NIR) fluorescent protein, miRFP720, and the fully NIR Forster resonance energy transfer (FRET) pair miRFP670-miRFP720, which together enabled design of biosensors compatible with CFP-YFP imaging and blue-green optogenetic tools. We developed a NIR biosensor for Rac1 GTPase and demonstrated its use in multiplexed imaging and light control of Rho GTPase signaling pathways. Specifically, we combined the Rac1 biosensor with CFP-YFP FRET biosensors for RhoA and for Rac1-GDI binding, and concurrently used the LOV-TRAP tool for upstream Rac1 activation. We directly observed and quantified antagonism between RhoA and Rac1 dependent on the RhoA-downstream effector ROCK; showed that Rac1 activity and GDI binding closely depend on the spatiotemporal coordination between these two molecules; and simultaneously observed Rac1 activity during optogenetic manipulation of Rac1.Peer reviewe

    Evolution of oxygen-ion and proton conductivity in Ca-Doped Ln2Zr2O7 (Ln = Sm, Gd), located near pyrochlore fluorite phase boundary

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    Sm2-xCaxZr2O7-x/2 (x = 0, 0.05, 0.1) and Gd2-xCaxZr2O7-x/2 (x = 0.05, 0.1) mixed oxides in a pyrochlore-fluorite morphotropic phase region were prepared via the mechanical activation of oxide mixtures, followed by annealing at 1600 ?C. The structure of the solid solutions was studied by X-ray diffraction and refined by the Rietveld method, water content was determined by thermogravimetry (TG), their bulk and grain-boundary conductivity was determined by impedance spectroscopy in dry and wet air (100-900 ?C), and their total conductivity was measured as a function of oxygen partial pressure in the temperature range: 700-950 ?C. The Sm2-xCaxZr2O7-x/2 (x = 0.05, 0.1) pyrochlore solid solutions, lying near the morphotropic phase boundary, have proton conductivity contribution both in the grain bulk and on grain boundaries below 600 ?C, and pure oxygen-ion conductivity above 700 ?C. The 500 ?C proton conductivity contribution of Sm2-xCaxZr2O7-x/2 (x = 0.05, 0.1) is ~ 1 ? 10-4 S/cm. The fluorite-like Gd2-xCaxZr2O7-x/2 (x = 0.1) solid solution has oxygen-ion bulk conductivity in entire temperature range studied, whereas proton transport contributes to its grain-boundary conductivity below 700 ?C. As a result, of the morphotropic phase transition from pyrochlore Sm2-xCaxZr2O7-x/2 (x = 0.05, 0.1) to fluorite-like Gd2-xCaxZr2O7-x/2 (x = 0.05, 0.1), the bulk proton conductivity disappears and oxygen-ion conductivity decreases. The loss of bulk proton conductivity of Gd2-xCaxZr2O7-x/2 (x = 0.05, 0.1) can be associated with the fluorite structure formation. It is important to note that the degree of Ca substitution in such solid solutions (Ln2-xCax)Zr2O7-? (Ln = Sm, Gd) is low, x < 0.1. In both series, grain-boundary conductivity usually exceeds bulk conductivity. The high grain-boundary proton conductivity of Ln2-xCaxZr2O7-x/2 (Ln = Sm, Gd; x = 0.1) is attributable to the formation of an intergranular CaZrO3-based cubic perovskite phase doped with Sm or Gd in Zr sublattice. ? 2019 by the authors.371C-9F16-EBDE | Eduarda GomesN/
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