100 research outputs found

    Influence of liquid properties on plain-jet airblast atomization

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    This thesis reports the results of a detailed programme of research on airblast atomization carried out using a specially designed plain-jet atomizer in which the fuel is injected into a high velocity airstream in the form of a discrete jet. Because recent studies on airblast atomization have been mainly confined to sheet and then subjected on both sides to the atomizing action of high velocity air, information was needed to carry out a comparison between^the two mechanisms of atomization. It was in order to obtain such information that the present investigation was undertaken and the study essentially resolved into a detailed experimental exploration of the spray characteristics of 1plain-j et1 airblast atomizers. Specially prepared liquids were employed to distinguish between the separate effects on S.M.D. (Sauter Mean Diameter of spray) of viscosity, surface tension and density. The liquids employed represented a range of values of viscosity from 1 .0 to 76 x 10 Kg/ms,/while surface tension and density were varied -3 3 between 26 and 73 x 10 N/m and 794 and 218oKg/m respectively. Atomizing air velocities covered the range of practical interest to the designers of continuous combustion systems and varied between 70 and 180 m/s. The effect of scale on S.M.D. was studied using several different fuel injectors varying in orifice diameter between 0.39 and 1.58 mm. A detailed description of the light-scattering technique for drop size measurement is included...Ph

    Glutamatergic neurons induce expression of functional glutamatergic synapses in primary myotubes.

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    The functioning of the nervous system depends upon the specificity of its synaptic contacts. The mechanisms triggering the expression of the appropriate receptors on postsynaptic membrane and the role of the presynaptic partner in the differentiation of postsynaptic structures are little known.To address these questions we cocultured murine primary muscle cells with several glutamatergic neurons, either cortical, cerebellar or hippocampal. Immunofluorescence and electrophysiology analyses revealed that functional excitatory synaptic contacts were formed between glutamatergic neurons and muscle cells. Moreover, immunoprecipitation and immunofluorescence experiments showed that typical anchoring proteins of central excitatory synapses coimmunoprecipitate and colocalize with rapsyn, the acetylcholine receptor anchoring protein at the neuromuscular junction.These results support an important role of the presynaptic partner in the induction and differentiation of the postsynaptic structures

    Distribution of different isoforms of receptor protein tyrosine phosphatase \u3b3 (Ptprg-RPTP \u3b3) in adult mouse brain: upregulation during neuroinflammation.

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    The receptor protein tyrosine phosphatase \u3b3 (Ptprg-RPTP\u3b3) is a receptor protein widely expressed in many tissues, including the central nervous system (CNS). Several RPTP\u3b3 isoforms are expressed in the brain during development and in adulthood, but their distribution and role are unknown. In this study, we investigated the distribution of some RPTP\u3b3 isoforms in the adult brain using antibodies against the epitopes localized in the C- and in the N-terminal domains of the full length isoform of RPTP\u3b3. We found a predominant and widespread neuronal positivity throughout the neocortex, hippocampus, striatum and in many nuclei of the brainstem and cerebellum. At least 2 distinct isoforms that can co-exist in various compartments in the same cell are detectable in different neuron types. Immunopositivity for epitopes located in both the N- and C-terminus domains were found in the neuropil of cortical and hippocampal neurons, whereas the N-terminal domain positivity was found in the soma, often without colocalization with its C-terminal counterpart. Among glial cells, some protoplasmic and perivascular astrocytes and the cerebellar Bergmann glia, express RPTP\u3b3. The astrocytic expression of RPTP\u3b3 and putative processing isoforms of 120 and 80 kDa increases during neuroinflammation, in particular 24 h after LPS treatment. Activated astrocytes were found to be strongly positive for RPTP\u3b3 also in a mice model of Alzheimer's disease. Our results confirm previous findings and enrich the current knowledge of RPTP\u3b3 distribution in the CNS, highlighting a role of RPTP\u3b3 during neuroinflammation processes

    Distribución profunda, aspectos biológicos y ecológicos de Aristeus Antennatus (Risso, 1816) en el Mediterráneo Occidental y Central

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    [EN] The object of the DESEAS Project, funded by the EC, was to gather preliminary data on the abundance and maximum depth distribution of the rose shrimp Aristeusantennatus in the Mediterranean Sea. An exploratory survey was therefore designed with that goal in mind and conducted on the R/V García del Cid, sampling the maximum depths in three specific areas in the central and western Mediterranean, one off Ibiza (Balearic Islands), one off Calabria (western Ionian Sea), and one off the southern Peloponnesian Peninsula (Gulf of Kalamata, eastern Ionian Sea). The depths sampled ranged from 600 to 4000 m, with specimens of A. antennatus being collected down to 3300 m. There were three distinct boundaries marking the abundance of this species: 1500 m, relatively low abundance (<100 ind km-2). The known population structure of this shrimp species, with increasing proportions of males and juveniles with depth, was also recorded in the deep-sea regions in other areas of the Mediterranean. No evidence of any differences in gonad development or in the presence of spermatophores carried by females was found in any of the three sampling areas. Lastly, a tendency for the relative proportion of juveniles to increase with depth was also observed[ES] El objetivo del proyecto DESEAS, financiado por la CE, fue obtener datos preliminares de abundancia y distribución de profundidad máxima de la gamba rosada Aristeus antennatus en el Mar Mediterráneo. El diseño de la campaña exploratoria fue realizado con este propósito y se desarrolló a bordo del B/O García del Cid. Se realizaron muestreos en las máximas profundidades de tres áreas específicas en el Mediterráneo occidental y central: una cerca de Menorca (Islas Baleares), otra frente a las costas de Calabria (Iónico occidental) y la última al sur de la península del Peloponeso (en el Golfo de Kalamata, Iónico oriental). Las profundidades muestreadas fueron las comprendidas entre 600 y 4000 m, obteniendo individuos de A. antennatus hasta 3300 m. Se detectaron tres niveles de abundancias diferenciados en esta especie: 1500 m, relativamente poco abundante (< 100 ind km-2). En las tres áreas estudiadas se confirmó la estructura de la población conocida hasta el momento, es decir, aumento de la proporción de machos y juveniles con la profundidad. No se encontraron evidencias de diferencias en el desarrollo gonadal o en la presencia de espermatóforos de las hembras entre áreas. Finalmente se observó la existencia de una tendencia en el aumento de la proporción de juveniles con la profundidadThis work was financially supported by the Directorate General Fisheries of the EC as part of the DESEAS survey programme (DGXIV, Study Contract, 2000/39)Peer reviewe

    Rho GTPase-dependent plasticity of dendritic spines in the adult brain.

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    Brain activity is associated with structural changes in the neural connections. However, in vivo imaging of the outer cortical layers has shown that dendritic spines, on which most excitatory synapses insist, are predominantly stable in adulthood. Changes in dendritic spines are governed by small GTPases of the Rho family through modulation of the actin cytoskeleton. Yet, while there are abundant data about this functional effect of Rho GTPases in vitro, there is little evidence that Rho GTPase signaling in the brain is associated with changes in neuronal morphology. In the present work, both chronic in vivo two-photon imaging and Golgi staining reveal that the activation of Rho GTPases in the adult mouse brain is associated with little change of dendritic spines in the apical dendrites of primary visual cortex pyramidal neurons. On the contrary, considerable increase in spine density is observed i) in the basal dendrites of the same neurons ii) in both basal and apical dendrites of the hippocampal CA1 pyramidal cells. Moreover, functional analysis shows increase in basal glutamatergic neurotrasmission and activity-dependent plasticity only in CA1 neurons. While confirming that Rho-GTPase dependent increase in spine density can be substantial, the study indicates region and dendrite selectivity with relative stability of superficial cortical circuits

    Проект кожухотрубного теплообменника сернокислотного производства

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    Модернизация теплообменного оборудования с целью повышения ресурсоэффективности технологического процесса. В результате исследования была найдена необходимая поверхность теплообмена для обеспечения охлаждения серной кислоты в заданных параметрах.Modernization of heat exchange equipment in order to increase the resource efficiency of the technological process. As a result of the study, the necessary heat exchange surface was found to ensure the cooling of sulfuric acid in the specified parameters

    Operating a full tungsten actively cooled tokamak: overview of WEST first phase of operation

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    WEST is an MA class superconducting, actively cooled, full tungsten (W) tokamak, designed to operate in long pulses up to 1000 s. In support of ITER operation and DEMO conceptual activities, key missions of WEST are: (i) qualification of high heat flux plasma-facing components in integrating both technological and physics aspects in relevant heat and particle exhaust conditions, particularly for the tungsten monoblocks foreseen in ITER divertor; (ii) integrated steady-state operation at high confinement, with a focus on power exhaust issues. During the phase 1 of operation (2017–2020), a set of actively cooled ITER-grade plasma facing unit prototypes was integrated into the inertially cooled W coated startup lower divertor. Up to 8.8 MW of RF power has been coupled to the plasma and divertor heat flux of up to 6 MW m−2 were reached. Long pulse operation was started, using the upper actively cooled divertor, with a discharge of about 1 min achieved. This paper gives an overview of the results achieved in phase 1. Perspectives for phase 2, operating with the full capability of the device with the complete ITER-grade actively cooled lower divertor, are also described
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