48 research outputs found

    Analysis of Exo- and endocytosis in the mouse nerve ending in experimental diabetes mellitus

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    Diabetes mellitus (DM) is a systemic disease characterized by changes in many organs and tissues, including the motor system. The aim of this work was a study of the processes of exo- and endocytosis in the motor nerve ending of mouse diaphragm during high-frequency activity in experimental alloxan model of DM. Endplate potentials (EPPs) was recorded using intracellular microelectrodes during single and high-frequency (50 Hz, 1 min) stimulation. In mice with experimental DM the amplitude-temporary parameters of EPPs did not differ from the control; however, an increase in the EPPs depression and a slower recovery was observed during high frequency stimulation. Using an endocytosis dye FM 1-43, it was shown that in animals with experimental DM the intensity of fluorescence of nerve terminals loaded by high-frequency stimulation was higher than in control. This effect was prevented by an inhibitor of slow dynamin-mediated endocytosis - 1-azakenpaullone (2 μM). In addition, the bleaching of pre-loaded nerve terminals during high-frequency stimulation was slower in animals with DM. The obtained results suggest that in experimental DM the recycling of synaptic vesicles via the long path becomes more pronounced and the mechanisms of the vesicular transport are impaired. This hypothesis was confirmed by methods of mathematical modeling

    Characterization of Ni-Cd Nanostructured System Obtained by Chemical Reduction of Salts

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    The process of obtaining of highly dispersed metal powders of Ni-Cd system by reduction of their salts by hydrazine in aqueous medium at high alkalinity was investigated. The possibility of production metal powders containing up to 50 mol% of cadmium is established and conditions for their synthesis are optimized. Phase composition, structural parameters, dispersity of solid products during the reduction process were studied by X-ray diffraction (XRD) and SAXS. The formation of metal solid solutions with FCC lattice contradicts to the known phase diagram for Ni-Cd and may be explained by increasing the energy of the particles in the nanostate. The formation of intermetallide NiCd5 in the studied compositions area is caused by sequential character of reduction process; as a result the metal product on the initial stage of reduction is significantly enriched with cadmium

    Dressing with Control: using integrability to generate desired solutions to Einstein's equations

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    21 pages, no figures21 pages, no figures21 pages, no figures21 pages, no figuresMotivated by integrability of the sine-Gordon equation, we investigate a technique for constructing desired solutions to Einstein's equations by combining a dressing technique with a control-theory approach. After reviewing classical integrability, we recall two well-known Killing field reductions of Einstein's equations, unify them using a harmonic map formulation, and state two results on the integrability of the equations and solvability of the dressing system. The resulting algorithm is then combined with an asymptotic analysis to produce constraints on the degrees of freedom arising in the solution-generation mechanism. The approach is carried out explicitly for the Einstein vacuum equations. Applications of the technique to other geometric field theories are also discussed

    Globular Clusters as Candidates for Gravitational Lenses to Explain Quasar-Galaxy Associations

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    We argue that globular clusters (GCs) are good candidates for gravitational lenses in explaining quasar-galaxy associations. The catalog of associations (Bukhmastova 2001) compiled from the LEDA catalog of galaxies (Paturel 1997) and from the catalog of quasars (Veron-Cetty and Veron 1998) is used. Based on the new catalog containing 8382 pairs, we show that one might expect an increased number of GCs around irregular galaxies of types 9 and 10 from the hypothesis that distant compact sources are gravitationally lensed by GCs in the halos of foreground galaxies. The King model is used to determine the central surface densities of 135 GCs in the Milky Way. The distribution of GCs in central surface density was found to be lognormal.Comment: 22 pages, 4 figure

    Kinetics of exciton photoluminescence in type-II semiconductor superlattices

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    The exciton decay rate at a rough interface in type-II semiconductor superlattices is investigated. It is shown that the possibility of recombination of indirect excitons at a plane interface essentially affects kinetics of the exciton photoluminescence at a rough interface. This happens because of strong correlation between the exciton recombination at the plane interface and at the roughness. Expressions that relate the parameters of the luminescence kinetics with statistical characteristics of the rough interface are obtained. The mean height and length of roughnesses in GaAs/AlAs superlattices are estimated from the experimental data.Comment: 3 PostScript figure

    Darboux transformations, finite reduction groups and related Yang-Baxter maps

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    In this paper we construct Yang-Baxter (YB) maps using Darboux matrices which are invariant under the action of finite reduction groups. We present 6-dimensional YB maps corresponding to Darboux transformations for the Nonlinear Schr\"odinger (NLS) equation and the derivative Nonlinear Schr\"odinger (DNLS) equation. These YB maps can be restricted to 44-dimensional YB maps on invariant leaves. The former are completely integrable and they also have applications to a recent theory of maps preserving functions with symmetries \cite{Allan-Pavlos}. We give a 66- dimensional YB-map corresponding to the Darboux transformation for a deformation of the DNLS equation. We also consider vector generalisations of the YB maps corresponding to the NLS and DNLS equation.Comment: 18 pages, revised version. The format of the paper has changed, we added one sectio

    Extended parametric resonances in nonlinear Schrodinger systems

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    We study an example of exact parametric resonance in a extended system ruled by nonlinear partial differential equations of nonlinear Schr\"odinger type. It is also conjectured how related models not exactly solvable should behave in the same way. The results have applicability in recent experiments in Bose-Einstein condensation and to classical problems in Nonlinear Optics.Comment: 1 figur

    Bose--Einstein solitons in highly asymmetric traps

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    We obtain analytic solutions to the Gross-Pitaevskii equation with negative scattering length in highly asymmetric traps. We find that in these traps the Bose--Einstein condensates behave like quasiparticles and do not expand when the trapping in one direction is eliminated. The results can be applicable to the control of the motion of Bose--Einstein condensates.Comment: 12 pages, Latex, Figures available under request on [email protected]

    Данные мониторинга суицидальных попыток и завершенных суицидов в г. Одессе за период 2001-2011 гг.

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    Статья посвящена анализу суицидальной активности населения миллионного города. Данные многолетнего мониторинга позволяют выявить совпадающую динамику уровней суицидальных попыток и самоубийств в течение 11 лет наблюдения (2001-2011 гг.). Выявлены типичные различия между мужчинами и женщинами (преобладание попыток среди женщин и завершенных самоубийств среди мужчин). Способы попыток и суицидов свидетельствуют о том, что мужчины используют более агрессивные методы самоповреждения. В последние годы наблюдается рост самоубийств среди мужчин в возрастной группе 25-29 лет.The study deals with the suicidal activity of the population of a million city. Long-lasting monitoring data revealed very similar changes of attempted and completed suicides rates over 11 years of monitoring. Rather typical differences between males and females suicidal behaviors are found: higher attempts rates in females and higher completed suicides in males. Methods of attempts and suicides testify that males choose more violent means. During last period growingsuicides are registered in males aged 25-29 years

    Structure of Core-Shell Ni/Au Nanoparticles Synthesized in Two-Stage Process From Aqueous Salt Solutions

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    Core-shell Ni/Au nanoparticles are synthesized in a two-stage process in aqueous solutions. The core-shell structure of the synthesized particles is proven by using results of HRTEM, TEM, SAXS and CVA methods. The thickness of the core is estimated at 1 nm and it is formed from 1–2 layers of mutually oriented gold crystallites. The CVA results show that the Au-shells are nanoporous, and that a layer of nickel oxidation products is formed. These results were obtained by using Vis spectrophotometer, TEM, HRTEM, SAXS, CVA and elemental analysis
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