10 research outputs found

    Variability and directionality of inferior olive neuron dendrites revealed by detailed 3D characterization of an extensive morphological library

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    The inferior olive (IO) is an evolutionarily conserved brain stem structure and its output activity plays a major role in the cerebellar computation necessary for controlling the temporal accuracy of motor behavior. The precise timing and synchronization of IO network activity has been attributed to the dendro-dendritic gap junctions mediating electrical coupling within the IO nucleus. Thus, the dendritic morphology and spatial arrangement of IO neurons governs how synchronized activity emerges in this nucleus. To date, IO neuron structural properties have been characterized in few studies and with small numbers of neurons; these investigations have described IO neurons as belonging to two morphologically distinct types, “curly” and “straight”. In this work we collect a large number of individual IO neuron morphologies visualized using different labeling techniques and present a thorough examination of their morphological properties and spatial arrangement within the olivary neuropil. Our results show that the extensive heterogeneity in IO neuron dendritic morphologies occupies a continuous range between the classically described “curly” and “straight” types, and that this continuum is well represented by a relatively simple measure of “straightness”. Furthermore, we find that IO neuron dendritic trees are often directionally oriented. Combined with an examination of cell body density distributions and dendritic orientation of adjacent IO neurons, our results suggest that the IO network may be organized into groups of densely coupled neurons interspersed with areas of weaker coupling

    Highly enhanced transport by supersonic N-crowdions

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    An interstitial atom placed in a close‐packed atomic row of a crystal is called crowdion. Such defects are highly mobile, they can move along the row transporting mass and energy. In the present study the concept of the classical supersonic crowdion is generalized to N ‐crowdion in which not one but N atoms move simultaneously at a high speed. With the help of molecular dynamics simulations for fcc Morse crystal it is demonstrated that N ‐crowdions are much more efficient in mass transport being able to propagate through larger distances having smaller total energy than the classical 1‐crowdion

    Optimization of geometry forms for wind mill mouth of the “rotor-in-socket” type

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    Introduction. The method and results of the aerodynamic research of the vertical axis wind power plants (WPP) with an axisymmetric stator are considered. The work objective is to show the application perspectiveness of vertical axis wind-power plants of the specified type for the national economy. Materials and Methods. The technique of virtual aerodynamic blasting and the corresponding design optimization at the specified criterion are used to perform the tasks. Within the framework of this technique, numerical aerodynamic analysis of a single rotor of the given type, and of the “rotor + socket” system before and after the optimization at the specified parameters of the freestream and rotor spinning is performed. When comparing the power of the obtained optimized WPP design with analogs, other things being equal, the aerodynamic similarity method is used. Research Results. Representative patterns of the aerodynamic flow around the investigated WPP type are obtained before and after the optimization. The distinctive distributions of the scalar and vector fields at the given parameters of the freestream and rotor spinning are studied. Dependent graphs are plotted against the linear freestream velocity for the projections of the rotor shaft moment (with WPP standard and optimized forms), as well as for the corresponding useful and side powers. A comparison of the power of the optimized WPP under consideration, and analogues, other factors being equal, is made. Discussion and Conclusions. The application perspectiveness of the vertical axis wind turbines with an axisymmetric stator designed to create useful interference with the rotor in order to increase useful shaft power is shown. Such wind power plants meet and exceed, at any rate upon the average, the corresponding classical vertical axis structures

    Aillikites and Alkali Ultramafic Lamprophyres of the Beloziminsky Alkaline Ultrabasic-Carbonatite Massif: Possible Origin and Relations with Ore Deposits

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    The 650–621 Ma plume which impinged beneath the Siberian craton during the breakup of Rodinia caused the formation of several alkaline carbonatite massifs in craton margins of the Angara rift system. The Beloziminsky alkaline ultramafic carbonatite massif (BZM) in the Urik-Iya graben includes alnöites, phlogopite carbonatites and aillikites. The Yuzhnaya pipe (YuP) ~ 645 Ma and the 640–621 Ma aillikites in BZM, dated by 40Ar/39Ar, contain xenoliths of carbonated sulfide-bearing dunites, xenocrysts of olivines, Cr-diopsides, Cr-phlogopites, Cr-spinels (P ~ 4–2 GPa and T ~ 800–1250 °C) and xenocrysts of augites with elevated HFSE, U, Th. Al-augites and kaersutites fractionated from T ~ 1100–700 °C along the 90 mW/m2 geotherm. Higher T trend for Al-Ti augite, pargasites, Ti-biotites series (0.4–1.5 GPa) relate to intermediate magma chambers near the Moho and in the crust. Silicate xenocrysts show Zr-Hf, Ta-Nb peaks and correspond to carbonate-rich magma fractionation that possibly supplied the massif. Aillikites contain olivines, rare Cr-diopsides and oxides. The serpentinites are barren, fragments of ore-bearing Phl carbonatites contain perovskites, Ta-niobates, zircons, thorites, polymetallic sulphides and Ta-Mn-Nb-rich magnetites, ilmenites and Ta-Nb oxides. The aillikites are divided by bulk rock and trace elements into seven groups with varying HFSE and LILE due to different incorporation of carbonatites and related rocks. Apatites and perovskites reveal remarkably high LREE levels. Aillikites were generated by 1%–0.5% melting of the highly metasomatized mantle with ilmenite, perovskite apatite, sulfides and mica, enriched by subduction-related melts and fluids rich in LILE and HFSE. Additional silicate crystal fractionation increased the trace element concentrations. The carbonate-silicate P-bearing magmas may have produced the concentration of the ore components and HFSE in the essentially carbonatitic melts after liquid immiscibility in the final stage. The mechanical enrichment of aillikites in ore and trace element-bearing minerals was due to mixture with captured solid carbonatites after intrusion in the massif

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    Genetic and Epigenetic Aspects of Skin Collagen Fiber Turnover and Functioning

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    One of the most important functions of the skin, i.e., protection from mechanical damage, is ensured by collagen fibers and their interaction with other elements in the extracellular matrix. Collagen fiber turnover is a complex multi-stage process. At each stage, a disruption may occur, leading to a decrease in the mechanical properties of the connective tissue. Clinically, collagen formation disorders manifest themselves as increased flabbiness and looseness of the skin and as early signs of facial aging. In addition to the clinical picture, it is important for cosmetologists and dermatologists to understand the etiology and pathogenesis of collagenopathies. In our review, we summarized and systematized the available information concerning the role of genetic and epigenetic factors in skin collagen fiber turnover. Furthermore, we focused on the functions of different types of collagens present in the skin. Understanding the etiology of impaired collagen formation can allow doctors to prescribe pathogenetically based treatments, achieve the most effective results, and minimize adverse reactions
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