579 research outputs found

    Electromagnetic levitation coil fabrication technique for MSFC containerless processing facilities

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    A technique is described for more reproducible fabrication of electromagnetic levitation coils. A split mandrel was developed upon which the coil is wound. After fabrication the mandrel can be disassembled to remove it from the coil. Previously, a full day was required to fabricate a levitation coil and the success rate for a functional coil was only 50 percent. About eight coils may be completed in one day using the technique developed and 95 percent of them are good levitation coils

    Influence of migrating inhibitor concentration on corrosion resistance of steel reinforcement in concrete

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    To increase the service life and durability of reinforced concrete structures, new technologies have been developed, such as cathodic protection, re-alkalinization, chloride extraction, and the use of corrosion inhibitors. This study evaluated the influence of cement type, concrete cover thickness, and the addition of organic migrating corrosion inhibitor (MCI) on the corrosion resistance of the embedded steel in concrete against the induced action of chloride ions. To accomplish this, corrosion tests were carried out using electrode potential techniques simultaneously with acceleration cycles of chloride attack. Four mixtures with two levels of reinforcement cover (25 and 40 mm) were subjected to 30 weekly cycles of chemical attack: a reference mixture (without inhibitor) and three others adopting concentration levels of 0.30%, 0.45%, and 0.60% of MCI in the volume of concrete. The concrete properties (compressive strength, voids, specific gravity, and water absorption by immersion and capillarity) were verified. In the corrosion tests on reinforced concrete with lower cover thickness, the mixture with 0.60% MCI addition showed the best results: corrosion potential values less negative than -200 mV, with less than 10% probability of corrosion.Para aumentar a vida útil e durabilidade das estruturas de concreto armado foram desenvolvidas novas tecnologias como a proteção catódica, re-alcalinização, extração de cloreto, e o uso de inibidores de corrosão. Este estudo avaliou a influência do tipo de cimento, espessura do cobrimento de concreto e adição de inibidor de corrosão orgânico migratório (MCI) na resistência à corrosão do aço embutido no concreto contra a ação induzida de íons cloreto. Para isso, foram realizados ensaios de corrosão utilizando técnicas de potencial de eletrodo simultaneamente com ciclos de aceleração de ataque de cloretos. Quatro misturas com dois níveis de cobertura do aço (25 e 40 mm) foram submetidas a 30 ciclos semanais de ataque químico: uma mistura de referência (sem inibidor) e outras três adotando níveis de concentração de 0,30%, 0,45% e 0,60% de MCI em volume de concreto. As propriedades do concreto (resistência à compressão, índice de vazios, massa específica e absorção de água por imersão e capilaridade) foram verificadas. Nos ensaios de corrosão em concretos armados com menor espessura de cobrimento, a mistura com adição de 0,60% de MCI apresentou os melhores resultados: valores de potencial de corrosão inferiores a -200 mV, com probabilidade de corrosão inferior a 10%

    Patterns of labour solidarity towards precarious workers and the unemployed in critical times in Greece, Poland and the UK

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    The purpose of this article is to examine whether and by what means traditional unions and other labour-oriented organisations engage in solidarity activities in favour of precarious workers and the unemployed. Our findings derive from qualitative data analysed from 10 in-depth interviews per country conducted as part of a large collaborative project with participants sampled from trade unions and other labour-oriented solidarity organisations based in three European national contexts: Greece, Poland, and the UK. Our aim here is to discern common features and differences in the strategies and answers given, within the three national contexts. To this end, we examine the actors engaged in labour solidarity; the value frames upon which these actions draw; the beneficiaries of their solidarity actions; the type of activities adopted mainly in favour of precarious workers and the unemployed; and their engagement in transnational labour solidarity activities

    Using competence modeling to create knowledge engineering team

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    The present paper is about applying competence modeling for a knowledge engineer in the case of the company WBSA Sistemas Inteligentes S.A. The process was based on Lucia and Lepsinger model, by which competences are characterized through the identification of situations and behaviors considered relevant to the engineer performance. As one of the different techniques suggested by the model for collecting data, a number of individual interviews were undertaken and at the end it was defined and validated a set of eleven competence regarded as necessary for a satisfactory performance of a knowledge engineerApplications in Artificial Intelligence - Knowledge EngineeringRed de Universidades con Carreras en Informática (RedUNCI

    Direct comparison of steroid and non-steroid eluting small surface pacing leads: Randomized, multicenter clinical trial

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    BACKGROUND: The aim of the study was to evaluate the effi cacy and safety of small surface steroid-eluting atrial and ventricular pacing leads in comparison to non-steroid leads using remote monitoring system (Biotronik Home Monitoring(R)). METHODS: In this randomized multicenter prospective trial, SIELLO T steroid-eluting ventricular leads (n = 42) were compared to BPPU T non-steroid leads (n = 46) and SIELLO JT steroid-eluting atrial leads (n = 24) to BPPU JT non-steroid leads (n = 27) (Biotronik, Berlin, Germany) in pacemaker devices with remote monitoring capabilities. Lead parameters were evaluated during implantation, at 1-week and 1, 3, 6-month outpatient follow-up. Remote monitoring data were collected weekly. RESULTS: Atrial and ventricular steroid-eluting leads had stable sensing and impedance as compared to non-steroid leads at implantation and during follow-up. Patients with non-steroid atrial leads had signifi cantly higher threshold compared to steroid leads at 1-week and at 1, 3, 6-month follow-up with a peak at 1-month (1-month 1.4 +/- 0.6 vs. 0.7 +/- 0.3 V at 0.4 ms, p < 0.001; 6-month 0.3 +/- 0.5 vs. 0.2 +/- 0.3 V at 0.4 ms, p = 0.002). Patients with non-steroid ventricular leads had signifi cantly higher threshold compared to steroid leads at 1, 3, 6-month (6-month 1.0 +/- 0.3 vs. 0.6 +/- 0.2 V at 0.4 ms, p < 0.001). Remote monitoring confi rmed consistent results. During the study, 3 patients died of non-lead-related death. Lead repositioning was necessary in 2 atrial, 2 ventricular steroid leads and in 1 ventricular non-steroid lead. CONCLUSIONS: Atrial and ventricular pacemaker leads with steroid showed signifi cantly lower pacing threshold compared to non-steroid leads, confi rmed by remote monitoring

    Prohibitin 1 Modulates Mitochondrial Stress-Related Autophagy in Human Colonic Epithelial Cells

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    Autophagy is an adaptive response to extracellular and intracellular stress by which cytoplasmic components and organelles, including damaged mitochondria, are degraded to promote cell survival and restore cell homeostasis. Certain genes involved in autophagy confer susceptibility to Crohn's disease. Reactive oxygen species and pro-inflammatory cytokines such as tumor necrosis factor α (TNFα), both of which are increased during active inflammatory bowel disease, promote cellular injury and autophagy via mitochondrial damage. Prohibitin (PHB), which plays a role in maintaining normal mitochondrial respiratory function, is decreased during active inflammatory bowel disease. Restoration of colonic epithelial PHB expression protects mice from experimental colitis and combats oxidative stress. In this study, we investigated the potential role of PHB in modulating mitochondrial stress-related autophagy in intestinal epithelial cells.We measured autophagy activation in response to knockdown of PHB expression by RNA interference in Caco2-BBE and HCT116 WT and p53 null cells. The effect of exogenous PHB expression on TNFα- and IFNγ-induced autophagy was assessed. Autophagy was inhibited using Bafilomycin A(1) or siATG16L1 during PHB knockdown and the affect on intracellular oxidative stress, mitochondrial membrane potential, and cell viability were determined. The requirement of intracellular ROS in siPHB-induced autophagy was assessed using the ROS scavenger N-acetyl-L-cysteine.TNFα and IFNγ-induced autophagy inversely correlated with PHB protein expression. Exogenous PHB expression reduced basal autophagy and TNFα-induced autophagy. Gene silencing of PHB in epithelial cells induces mitochondrial autophagy via increased intracellular ROS. Inhibition of autophagy during PHB knockdown exacerbates mitochondrial depolarization and reduces cell viability.Decreased PHB levels coupled with dysfunctional autophagy renders intestinal epithelial cells susceptible to mitochondrial damage and cytotoxicity. Repletion of PHB may represent a therapeutic approach to combat oxidant and cytokine-induced mitochondrial damage in diseases such as inflammatory bowel disease

    A novel interaction between ATOH8 and PPP3CB

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    ATOH8 is a bHLH transcription factor playing roles in a variety of developmental processes such as neurogenesis, differentiation of pancreatic precursor cells, development of kidney and muscle, and differentiation of endothelial cells. PPP3CB belongs to the catalytic subunit of the serine/threonine phosphatase, calcineurin, which can dephosphorylate its substrate proteins to regulate their physiological activities. In our study, we demonstrated that ATOH8 interacts with PPP3CB in vitro with different approaches. We show that the conserved catalytic domain of PPP3CB interacts with both the N-terminus and the bHLH domain of ATOH8. Although the interaction domain of PPP3CB is conserved among all isoforms of calcineurin A, ATOH8 selectively interacts with PPP3CB instead of PPP3CA, probably due to the unique proline-rich region present in the N-terminus of PPP3CB, which controls the specificity of its interaction partners. Furthermore, we show that inhibition of the interaction with calcineurin inhibitor, cyclosporin A (CsA), leads to the retention of ATOH8 to the cytoplasm, suggesting that the interaction renders nuclear localization of ATOH8 which may be critical to control its activity as transcription factor

    HSP27 induced glaucomatous damage in mice of young and advanced age

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    IntroductionAge-related diseases such as glaucoma, a leading cause of blindness, are having an upward trend due to an aging society. In glaucoma, some patients display altered antibody profiles and increased antibody titers, for example against heat shock protein 27 (HSP27). An intravitreal injection of HSP27 leads to glaucoma-like damage in rats. We now aimed to investigate if aged mice are more prone to this damage than younger ones.MethodsWe intravitreally injected HSP27 into young (1–2 months) and aged (7–8 months) mice to compare glaucomatous damage. Respective age-matched controls received PBS. Not injected eyes served as naive controls.ResultsOptical coherence tomography 4 weeks after injection showed no changes in retinal thickness in all groups at both ages. Cell counts and RT-qPCR revealed a significant reduction in RGC numbers in HSP27 mice at both ages. Comparing aged and young HSP27 mice, no differences in Rbpms and Pou4f1 (RGCs) expression was detected, while the Tubb3 expression (neuronal cells) was significantly upregulated in aged HSP27 animals. Neither microglia/macrophages nor (resident) microglia counts revealed significant differences in HSP27 mice at both ages. Nevertheless, increased relative Iba1 and Tmem119 expression was detected in young and aged HSP27 mice. Aged HSP27 mice displayed a significantly lower Iba1 expression than young ones, whereas Cd68 levels were upregulated. A larger GFAP+ area and an upregulation of GFAP expression in HSP27 animals of both ages indicated a macrogliosis. Also, elevated Il1b and Nos2 expression levels were observed in young and aged HSP27 mice. However, only Il1b levels were upregulated when comparing 7–8 months to 1–2 months old animals. A larger HSP25+ area was seen in aged HSP27 animals, while Hspb2 expression levels were downregulated in both HSP27 groups. The aged HSP27 group displayed an upregulated Hspb2 expression compared to young mice. Furthermore, a higher optic nerve degeneration score was noted in young and aged HSP27 groups.DiscussionThese findings indicate that an intravitreal injection of HSP27 led to RGC loss accompanied by inflammation. Age-dependent effects (7–8 months vs. 1–2 months) were not very prominent. The results suggest a potential role of extracellular HSP27 in the development of glaucoma

    Intravitreal S100B Injection Leads to Progressive Glaucoma Like Damage in Retina and Optic Nerve

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    The glial protein S100B, which belongs to a calcium binding protein family, is up-regulated in neurological diseases, like multiple sclerosis or glaucoma. In previous studies, S100B immunization led to retinal ganglion cell (RGC) loss in an experimental autoimmune glaucoma (EAG) model. Now, the direct degenerative impact of S100B on the retina and optic nerve was evaluated. Therefore, 2 μl of S100B was intravitreally injected in two concentrations (0.2 and 0.5 μg/μl). At day 3, 14 and 21, retinal neurons, such as RGCs, amacrine and bipolar cells, as well as apoptotic mechanisms were analyzed. Furthermore, neurofilaments, myelin fibers and axons of optic nerves were evaluated. In addition, retinal function and immunoglobulin G (IgG) level in the serum were measured. At day 3, RGCs were unaffected in the S100B groups, when compared to the PBS group. Later, at days 14 and 21, the RGC number as well as the β-III tubulin protein level was reduced in the S100B groups. Only at day 14, active apoptotic mechanisms were noted. The number of amacrine cells was first affected at day 21, while the bipolar cell amount remained comparable to the PBS group. Also, the optic nerve neurofilament structure was damaged from day 3 on. At day 14, numerous swollen axons were observed. The intraocular injection of S100B is a new model for a glaucoma like degeneration. Although the application site was the eye, the optic nerve degenerated first, already at day 3. From day 14 on, retinal damage and loss of function was noted. The RGCs in the middle part of the retina were first affected. At day 21, the damage expanded and RGCs had degenerated in all areas of the retina as well as amacrine cells. Furthermore, elevated IgG levels in the serum were measured at day 21, which could be a sign of a late and S100B independet immune response. In summary, S100B had a direct destroying impact on the axons of the optic nerve. The damage of the retinal cell bodies seems to be a consequence of this axon loss
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