Etude du comportement mécanique de matériaux composites à matrice polypropylène et charges minérales recyclées

Résumé : Dans ce travail, on s’intéresse à l’influence de la nature de la charge sur le comportement mécanique de matériaux composites à matrice polypropylène homopolymère (PPH). On procède au rajout de charges minérales qui sont, la fibre de verre, la poudre de verre récupérée des lampes à néon usagées et de la chaux. Ces charges sont rajoutées aux concentrations de 5 et 10% à la matrice PPH. Le mélangeage a été effectué à froid puis à chaud par extrusion. L’élaboration des éprouvettes a été effectuée par procédé d’injection après broyage du produit d’extrusion. La caractérisation mécanique des échantillons a montré que la fibre de verre engendre une amélioration du module d’élasticité aux concentrations de 5 et 10%. Pour la chaux et la poudre de verre, les variations sont relativement faibles. La contrainte élastique maximale est faiblement affectée par la fibre de verre. Par contre elle diminue pour la chaux et la poudre de verre. Concernant la résilience, on enregistre un gain de 25% pour la fibre de verre, une diminution de l’ordre de 20% pour la poudre de verre et une faible variation pour 10% de chaux. L’analyse des faciès de rupture par MEB a révélé le caractère fragile de la rupture par traction des différents mélanges

Characteristics and management of congenital esophageal stenosis: findings from a multicenter study.

BACKGROUND: Congenital esophageal stenosis (CES) is a rare condition frequently associated with esophageal atresia (EA). There are limited data from small series about the presentation, treatment, and outcomes of CES. METHODS: Medical records of all patients with CES included in the French Network on Esophageal Malformations and Congenital Diseases were reviewed retrospectively with regard to diagnosis, treatment, and outcome. RESULTS: Over 18 years, 61 patients (30 boys) had CES, and 29 (47%) of these patients also had EA. The mean age at diagnosis was 24 months (1 day to 14 years) and was younger in patients with CES and EA than in those with isolated CES (7 vs. 126 months, p < 0.05). Twenty-one of the 61 patients with CES had no clinical symptoms: in three patients, the findings were incidental, and in 18 of the 29 patients with associated EA, CES was diagnosed at the time of surgical repair of EA or during a postoperative systematic esophageal barium study. In the 40 other patients, at diagnosis, 50% presented with dysphasia, 40% with vomiting, 50% with food impaction, and 42% with respiratory symptoms. Diagnosis of CES was confirmed by esophageal barium study (56/61) and/or esophageal endoscopy (50/61). Sixteen patients had tracheobronchial remnants (TBR), 40 had fibromuscular stenosis (FMS), and five had membrane stenosis (MS). Thirty-four patients (56%) were treated by dilation only (13/34 remained asymptomatic at follow-up); 15 patients were treated by dilation but required later surgery because of failure (4/15 remained asymptomatic at follow-up); and nine patients had a primary surgical intervention (4/9 were asymptomatic at follow-up). Dilation was complicated by esophageal perforation in two patients (3.4%). At follow-up, dysphagia remained in 36% (21/58) of patients, but the incidence did not differ between the EA and the isolated CS groups (10/29 vs. 7/32, p = 0.27). CONCLUSIONS: CS diagnosis can be delayed when associated with EA. Dilation may be effective for treating patients with FMS and MS, but surgical repair is often required for those with TBR. Our results show clearly that, regardless of the therapeutic option, dysphagia occurs frequently, and patients with CES should be followed over the long term

Pathogenic Variants in the Myosin Chaperone UNC-45B Cause Progressive Myopathy with Eccentric Cores

The myosin-directed chaperone UNC-45B is essential for sarcomeric organization and muscle function from Caenorhabditis elegans to humans. The pathological impact of UNC-45B in muscle disease remained elusive. We report ten individuals with bi-allelic variants in UNC45B who exhibit childhood-onset progressive muscle weakness. We identified a common UNC45B variant that acts as a complex hypomorph splice variant. Purified UNC-45B mutants showed changes in folding and solubility. In situ localization studies further demonstrated reduced expression of mutant UNC-45B in muscle combined with abnormal localization away from the A-band towards the Z-disk of the sarcomere. The physiological relevance of these observations was investigated in C. elegans by transgenic expression of conserved UNC-45 missense variants, which showed impaired myosin binding for one and defective muscle function for three. Together, our results demonstrate that UNC-45B impairment manifests as a chaperonopathy with progressive muscle pathology, which discovers the previously unknown conserved role of UNC-45B in myofibrillar organization

Pathogenic Variants in the Myosin Chaperone UNC-45B Cause Progressive Myopathy with Eccentric Cores.

The myosin-directed chaperone UNC-45B is essential for sarcomeric organization and muscle function from Caenorhabditis elegans to humans. The pathological impact of UNC-45B in muscle disease remained elusive. We report ten individuals with bi-allelic variants in UNC45B who exhibit childhood-onset progressive muscle weakness. We identified a common UNC45B variant that acts as a complex hypomorph splice variant. Purified UNC-45B mutants showed changes in folding and solubility. In situ localization studies further demonstrated reduced expression of mutant UNC-45B in muscle combined with abnormal localization away from the A-band towards the Z-disk of the sarcomere. The physiological relevance of these observations was investigated in C. elegans by transgenic expression of conserved UNC-45 missense variants, which showed impaired myosin binding for one and defective muscle function for three. Together, our results demonstrate that UNC-45B impairment manifests as a chaperonopathy with progressive muscle pathology, which discovers the previously unknown conserved role of UNC-45B in myofibrillar organization

Contribution of seismic attributes in the direct detection of hudrocarbon, case history of a permit in the south algerian sahara

The zone of interest is located in an important oil and gas zone; ils position near Berkine and Illizi basin makes it very important. Our study is based on the data collected on two seismic Hnes, according ta the lines A and B, which intersect on well-2. The present work is based on the study of the contribution of the seismic attributes, in particular the amplitude attribute presented by the A VO method, to the direct hydrocarbons detection. The use of the seismic attributes and above aIl the A VO method becomes very widespread those latest years. With this study wc wanted to show the sturdiness and the supply the additional information that can bring those attributes. We checked, in spite of the very po or quality of the data and the high noise level, that having recours ta attributes such as amplitude, frequency and phase yields an invaluable information concerning the nature ofthe fluid, the continuity of the reflectors. the localisation of the discontinuities etc ... ; many anomalies were localised in diverse places along the two profiles; those anomalies may be used like a mark during the future studies on the region. (Note: due to the confidentiality of the data, authors have kept seismic hnes and wells anonymous