357 research outputs found

    Mechanical properties of some materials used in airplane construction

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    Since lightness is desirable in airplane construction, greater stresses must be tolerated than in other kinds of construction. It is therefore necessary to have a more accurate knowledge of the greatest stresses that may occur and of the actual properties of the materials used. The Aeronautic Research Laboratories took the limit of elasticity as the basis of the strength calculations. Many tests were made of different steels, woods, aluminum alloys, and fabrics

    Protection of wooden airplane parts against moisture by means of varnish

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    The objects of the experiments herein described were to test the protection afforded by Valspar oil varnish against the absorption of moisture by wooden airplane parts and the consequent changes in their elastic properties and to compare some of the best Dutch varnishes with Valspar

    Кон'юнктурний аналіз розвитку ринку рекреаційних послуг АР Крим

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    Метою дослідження є кон’юнктурний аналіз розвитку ринку рекреаційних послуг АР Крим та порівняльна оцінка функціонування конкурентоспроможних рекреаційних районів

    The monoclonal antibody ER-BMDM1 recognizes a macrophage and dendritic cell differentiation antigen with aminopeptidase activity

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    Abstract Here we describe the reactivity of monoclonal antibody (mAb) ER-BMDM1, directed against a 160-kDa cell membrane-associated antigen (Ag) with aminopeptidase activity. The aminopeptidase recognized by ER-BMDM1 is present on various mouse macrophage (MΦ) and dendritic cell (DC) subpopulations as well as on microvillous epithelia. Analysis of ER-BMDM1 Ag expression in in vitro models of MΦ maturation revealed that the Ag is expressed at increasing levels upon maturation of MΦ. In vivo, high level expression of the ER-BMDM1 Ag occurs after thmonocytic stage of maturation, since bone marrow cells and peripheral blood monocytes are essentially ER-BMDM1 negative. Analysis of isolated-resident and elicited MΦ populations showed that ER-BMDM1 recognizes a specific subpopulation of mature MΦ: only some resident peritoneal and alveolar MΦ are ER-BMDM1 positive, whereas virtually all thioglycollate-elicited peritoneal exudate MΦ bind the mAb. In lymphoid organs, a subpopulation of MΦ is recognized as well as interdigitating cells (IDC) located in T cell areas. Phenotypic analysis of isolated DC- the in vitro equivalents of IDC - from spleen and lymph nodes confirmed that the majority of this important antigen-presenting cell population expresses the ER-BMDM1 aminopeptidase. The molecular characteristics of the ER-BMDM1 Ag suggest that it may represent the mouse homolog of human CD13

    Lipid-laden multilocular cells in the aging thymus are phenotypically heterogeneous

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    Intrathymic lipid-laden multilocular cells (LLMC) are known to express pro-inflammatory factors that might regulate functional activity of the thymus. However, the phenotype of ageassociated intrathymic LLMC is still controversial. In this study, we evaluated LLMC density in the aging thymus and better characterized their distribution, ultrastructure and phenotype. Our results show an increased density of LLMC in the thymus from 03 to 24 months of age. Morphologically, intrathymic LLMC exhibit fibroblastoid fusiform, globular or stellate shapes and can be found in the subcapsular region as well as deeper in the parenchyma, including the perivascular area. Some parenchymal LLMC were like telocytes accumulating lipids. We identified lipid droplets with different electrondensities, lipofuscin granules and autolipophagosomelike structures, indicating heterogeneous lipid content in these cells. Autophagosome formation in intrathymic LLMC was confirmed by positive staining for beclin-1 and perilipin (PLIN), marker for lipid droplet-associated proteins.We also found LLMC in close apposition to thymic stromal cells, endothelial cells, mast cells and lymphocytes. Phenotypically, we identified intrathymic LLMC as preadipocytes (PLIN+PPARγ2+), brown adipocytes (PLIN+UCP1+), macrophages (PLIN+Iba-1+) or pericytes (PLIN+NG2+) but not epithelial cells (PLIN- panCK+). These data indicate that intrathymic LLMC are already present in the young thymus and their density significantly increases with age. We also suggest that LLMC, which are morphologically distinct, establish direct contact with lymphocytes and interact with stromal cells. Finally, we evidence that intrathymic LLMC correspond to not only one but to distinct cell types accumulating lipids

    Magnetic properties of colloidal suspensions of interacting magnetic particles

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    We review equilibrium thermodynamic properties of systems of magnetic particles like ferrofluids in which dipolar interactions play an important role. The review is focussed on two subjects: ({\em i}) the magnetization with the initial magnetic susceptibility as a special case and ({\em ii}) the phase transition behavior. Here the condensation ("gas/liquid") transition in the subsystem of the suspended particles is treated as well as the isotropic/ferromagnetic transition to a state with spontaneously generated long--range magnetic order.Comment: Review. 62 pages, 4 figure

    Risk factors for intensive care admission in children with severe acute asthma in the Netherlands:a prospective multicentre study

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    Rationale: Severe acute asthma (SAA) can be fatal, but is often preventable. We previously observed in a retrospective cohort study, a three-fold increase in SAA paediatric intensive care (PICU) admissions between 2003 and 2013 in the Netherlands, with a significant increase during those years of numbers of children without treatment of inhaled corticosteroids (ICS). Objectives: To determine whether steroid-naïve children are at higher risk of PICU admission among those hospitalised for SAA. Furthermore, we included the secondary risk factors tobacco smoke exposure, allergic sensitisation, previous admissions and viral infections. Methods: A prospective, nationwide multicentre study of children with SAA (2-18 years) admitted to all Dutch PICUs and four general wards between 2016 and 2018. Potential risk factors for PICU admission were assessed using logistic regression analyses. Measurements and main results: 110 PICU and 111 general ward patients were included. The proportion of steroid-naïve children did not differ significantly between PICU and ward patients. PICU children were significantly older and more exposed to tobacco smoke, with symptoms >1 week prior to admission. Viral susceptibility was not a significant risk factor for PICU admission. Conclusions: Children with SAA admitted to a PICU were comparable to those admitted to a general ward with respect to ICS treatment prior to admission. Preventable risk factors for PICU admission were >7 days of symptoms without adjustment of therapy and exposure to tobacco smoke. Physicians who treat children with asthma must be aware of these risk factors
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