159 research outputs found

    Grain-Size Prediction Model in Aluminum Castings Manufactured by Low-Pressure Technology

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    The grain refinement in a real casting manufactured by Low Pressure Die Casting (LPDC) such as wheels and steering knuckles depends on the grain-refinement potential of the metal and the geometry of the part/process parameters.For this study, the effect of the cooling rate on the AlSi7Mg alloy with different metal qualities in terms of grain refinement was tested. The grain size has been metallographically evaluated in cylindrical test pieces and in the real wheels and steering knuckles manufactured at the Mapsa and Fagor Ederlan foundries. The Thermolan®-Al system has been used to evaluate the nucleation potential in terms of grain size on a standard cup. The grain size has been modeled taking into account the effect of the cooling rate measured in the center of the cylindrical test parts and the different grain-size potential. Different grades of refinement have been tested. The grain size measured in a real casting (wheel and steering knuckle) was used to calibrate the model for a real part in LPDC for different grain-size potential

    KV7.2 kanala: estruktura, erregulazioa eta kitzikagarritasun neuronalean duen ekintza

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    Potasio-kanalak ia zelula guztien mintzean agertzen dira eta funtzio biologiko garrantzitsuak betetzen dituzte; besteak beste, korronte elektrikoak kontrolatzen dituzte zelula kitzikagarrietan. KV7 kanalen familia 5 kidez osatuta dago (KV7.1-KV7.5), eta horiek kodetzen dituzten geneak patologia esanguratsuekin erlazionatzen dira. KV7 kanalen estrukturak zelula-mintzean txertaturiko 6 segmentuz osaturiko ohiko estruktura partekatzen du; N- eta C-muturrak zelula barnekoak dira. Neuronetan, KV7.2 eta KV7.3 kanalak agertzen dira batik bat; M-korrontea sortuz, neuronen kitzikagarritasuna kontrolatzen duena. M-korrontearen erregulazioa konplexua da seinaleztapen-bidezidor desberdinen bidez erregula baitaiteke. Gq/11 proteinari akoplaturiko hartzaileen bidez erregulatzen da eta seinaleztapen-bidezidorra desberdina da aktibatutako hartzailearen arabera. Horrela, azetilkolinaren M1 hartzaile muskarinikoak KV7.2-aren korrontea inhibituko du PIP2-aren agorpenaren ondorioz. Bradikininaren hartzaileak, ordea, IP3-ak eragindako kaltzio-kontzentrazioaren igoeraren bidez inhibituko du. Mekanismo horietan, hainbat proteinak hartzen dute parte, hala nola kalmodulinak, proteina kinasek eta ainguratze-proteinek. Berrikuspen honetan, KV7.2 kanalari erreparatuko diogu, hainbat gaixotasunen partaide izateagatik eta haren erregulazio konplexuagatik, ikuspuntu farmakologiko batetik itu interesgarria izan baitaiteke.; Potassium channels are present in almost all cell membranes and perform important biological functions, including electrical currents control in excitable cells. The KV7 channels familiy consists of 5 members (KV7.1-KV7.5) and the genes that encode them are related to significant pathologies. The structure of KV7 channels shares the usual six transmem-brane segment structure, with intracellular N- and C-termini. In neurons, KV7.2 and KV7.3 are the main channels, which generate the M-current that controls neuronal excitability. The M-current regulation is complex as it can be regulated by different signalling pathways. It is regulated by Gq/11-coupled receptors, and the signaling pathway depends on the activated receptor. Thus, the M1 muscarinic acetylcholine receptor inhibits KV7.2 current by PIP2 depletion. While the bradykinin receptor inhibits it through the calcium concentration increase driven by IP3. Among these mechanisms several proteins are involved, such as calmodulin, protein kinases and anchor proteins. In this review we will focus on KV7.2 channel, as it is involved in several diseases and for its complex regulation it can be an interesting target from a pharmacological point of view

    Decreased expression of miR-146a and miR-155 contributes to an abnormal Treg phenotype in patients with rheumatoid arthritis

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    Objectives: MicroRNAs (miRNAs) have been implicated in the pathogenesis of autoimmune diseases, not least for their critical role in the regulation of regulatory T cell (Treg) function. Deregulated expression of miR-146a and miR-155 has been associated with rheumatoid arthritis (RA). We therefore investigated miR-146a and miR-155 expression in Tregs of patients with RA and their possible impact on Treg function and disease activity. Methods: Expression of miR-146a and miR-155 was assessed in RA patients and controls. MiRNA expression was correlated with disease activity and expression of target genes. Interference with biological activity of miRNAs was evaluated in functional Treg assays. Results: Diminished upregulation of miR-146a and miR-155 in response to T cell stimulation was found in Tregs of RA patients. Diminution of miR-146a expression was observed in particular in patients with active disease, and correlated with joint inflammation. In patients with active RA, Tregs demonstrated a pro-inflammatory phenotype characterised by inflammatory cytokine expression. This was due to an augmented expression and activation of signal transducer and activator transcription 1 (STAT1), a direct target of miR-146a. Conclusions: Our results suggest that in RA miR-146a facilitates a pro-inflammatory phenotype of Tregs via increased STAT1 activation, and contributes thereby to RA pathogenesis

    Adaptive gene loss in the common bean pan-genome during range expansion and domestication

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    : The common bean (Phaseolus vulgaris L.) is a crucial legume crop and an ideal evolutionary model to study adaptive diversity in wild and domesticated populations. Here, we present a common bean pan-genome based on five high-quality genomes and whole-genome reads representing 339 genotypes. It reveals ~234 Mb of additional sequences containing 6,905 protein-coding genes missing from the reference, constituting 49% of all presence/absence variants (PAVs). More non-synonymous mutations are found in PAVs than core genes, probably reflecting the lower effective population size of PAVs and fitness advantages due to the purging effect of gene loss. Our results suggest pan-genome shrinkage occurred during wild range expansion. Selection signatures provide evidence that partial or complete gene loss was a key adaptive genetic change in common bean populations with major implications for plant adaptation. The pan-genome is a valuable resource for food legume research and breeding for climate change mitigation and sustainable agriculture

    Haemophilus influenzae carriage and antibiotic resistance profile in Belgian infants over a three-year period (2016–2018)

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    BackgroundNon-typeable Haemophilus influenzae has become increasingly important as a causative agent of invasive diseases following vaccination against H. influenzae type b. The emergence of antibiotic resistance underscores the necessity to investigate typeable non-b carriage and non-typeable H. influenzae (NTHi) in children.MethodsNasopharyngeal swab samples were taken over a three-year period (2016–2018) from 336 children (6–30 months of age) attending daycare centers (DCCs) in Belgium, and from 218 children with acute otitis media (AOM). Biotype, serotype, and antibiotic resistance of H. influenzae strains were determined phenotypically. Mutations in the ftsI gene were explored in 129 strains that were resistant or had reduced susceptibility to beta-lactam antibiotics. Results were compared with data obtained during overlapping time periods from 94 children experiencing invasive disease.ResultsOverall, NTHi was most frequently present in both carriage (DCC, AOM) and invasive group. This was followed by serotype “f” (2.2%) and “e” (1.4%) in carriage, and “b” (16.0%), “f” (11.7%), and “a” (4.3%) in invasive strains. Biotype II was most prevalent in all studied groups, followed by biotype III in carriage and I in invasive strains. Strains from both groups showed highest resistance to ampicillin (26.7% in carriage vs. 18.1% in invasive group). A higher frequency of ftsI mutations were found in the AOM group than the DCC group (21.6 vs. 14.9% – p = 0.056). Even more so, the proportion of biotype III strains that carried a ftsI mutation was higher in AOM compared to DCC (50.0 vs. 26.3% – p < 0.01) and invasive group.ConclusionIn both groups, NTHi was most frequently circulating, while specific encapsulated serotypes for carriage and invasive group were found. Biotypes I, II and III were more frequently present in the carriage and invasive group. The carriage group had a higher resistance-frequency to the analyzed antibiotics than the invasive group. Interestingly, a higher degree of ftsI mutations was found in children with AOM compared to DCC and invasive group. This data helps understanding the H. influenzae carriage in Belgian children, as such information is scarce

    Effective hematopoietic stem cell-based gene therapy in a murine model of hereditary pulmonary alveolar proteinosis

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    Hereditary pulmonary alveolar proteinosis due to GM-CSF receptor deficiency (herPAP) constitutes a life-threatening lung disease characterized by alveolar deposition of surfactant protein secondary to defective alveolar macrophage function. As current therapeutic options are primarily symptomatic, we have explored the potential of hematopoietic stem cell-based gene therapy. Using Csf2rb−/− mice, a model closely reflecting the human herPAP disease phenotype, we here demonstrate robust pulmonary engraftment of an alveolar macrophage population following intravenous transplantation of lentivirally corrected hematopoietic stem and progenitor cells. Engraftment was associated with marked improvement of critical herPAP disease parameters, including bronchoalveolar fluid protein, cholesterol and cytokine levels, pulmonary density on computed tomography scans, pulmonary deposition of Periodic Acid-Schiff+ material as well as respiratory mechanics. These effects were stable for at least nine months. With respect to engraftment and alveolar macrophage differentiation kinetics, we demonstrate the rapid development of CD11c+/SiglecF+ cells in the lungs from a CD11c–/SiglecF+ progenitor population within four weeks after transplantation. Based on these data, we suggest hematopoietic stem cell-based gene therapy as an effective and cause-directed treatment approach for herPAP

    Validation of the Body Concealment Scale for Scleroderma (BCSS): Replication in the Scleroderma Patient-centered Intervention Network (SPIN) Cohort

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    © 2016 Elsevier Ltd Body concealment is an important component of appearance distress for individuals with disfiguring conditions, including scleroderma. The objective was to replicate the validation study of the Body Concealment Scale for Scleroderma (BCSS) among 897 scleroderma patients. The factor structure of the BCSS was evaluated using confirmatory factor analysis and the Multiple-Indicator Multiple-Cause model examined differential item functioning of SWAP items for sex and age. Internal consistency reliability was assessed via Cronbach's alpha. Construct validity was assessed by comparing the BCSS with a measure of body image distress and measures of mental health and pain intensity. Results replicated the original validation study, where a bifactor model provided the best fit. The BCSS demonstrated strong internal consistency reliability and construct validity. Findings further support the BCSS as a valid measure of body concealment in scleroderma and provide new evidence that scores can be compared and combined across sexes and ages
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