270 research outputs found

    Finite deformations govern the anisotropic shear-induced area reduction of soft elastic contacts

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    Solid contacts involving soft materials are important in mechanical engineering or biomechanics. Experimentally, such contacts have been shown to shrink significantly under shear, an effect which is usually explained using adhesion models. Here we show that quantitative agreement with recent high-load experiments can be obtained, with no adjustable parameter, using a non-adhesive model, provided that finite deformations are taken into account. Analysis of the model uncovers the basic mechanisms underlying shear-induced area reduction, local contact lifting being the dominant one. We confirm experimentally the relevance of all those mechanisms, by tracking the shear-induced evolution of tracers inserted close to the surface of a smooth elastomer sphere in contact with a smooth glass plate. Our results suggest that finite deformations are an alternative to adhesion, when interpreting a variety of sheared contact experiments involving soft materials.Comment: Version accepted at J. Mech. Phys. Solids. It includes Supplementary Informatio

    Facteurs Predictifs De Malignite D\'un Nodule Thyroidien

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    Buts : étudier les facteurs prédictifs de malignité des nodules thyroïdiens et comparer nos résultats à ceux de la littérature. Patients et méthodes : Il s\'agit d\'une étude rétrospective a propos de 282 cas de nodules thyroïdiens opérés à l\' hôpital de Mahdia entre 1988 et 2003. Résultats : L\'âge moyen était de 44 ans. Le risque de malignité des nodules thyroïdiens était de 15,6% . Ce risque était plus important chez les hommes (50%) que chez les femmes (13,3%). Certains facteurs étaient hautement prédictifs de malignité comme l\'âge supérieur à 60 ans, les signes de compression, les adénopathies cervicales et le caractère fixe et dure du nodule thyroidien Conclusion : Certains signes cliniques et para cliniques ont une grande valeur en matière de bénignité ou de malignité des nodules thyroïdiens.Aim : Study the predictive factors of malignancy of thyroid gland nodules and compare our results to those of the literature. Patients and methods : A retrospective study about 282 cases of thyroid gland nodules treated in Madhya hospital between 1988 and 2003. Results : The middle age was 44 years. The risk of malignancy was 15,6 %. This risk was higher in men (50 %) then in women (13,3 %). Some factors were highly predictive of malignancy like age superior then 60 years, neck lymph nodes … Conclusion: Some clinic and para clinic signs have an important value in benignancy or malignancy of thyroid gland nodules. Journal Tunisien d\'ORL et de chirurgie cervico-faciale Vol. 18 2007: pp. 20-2

    Histiocytose langerhansienne multiviscerale avec atteinte auriculaire bilaterale a propos d’une observation

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    L’histiocytose langerhansienne multi-viscérale est une prolifération clonale des cellules de Langerhans, touchant plusieurs organes. Cette entité se voit surtout chez l’enfant. Dans ce travail, nous rappelons les aspects cliniques avec la fréquence d’atteinte oto-rhino-laryngologique, ainsi que les moyens de diagnostic et le traitement de cette affection rare. Nous présentons le cas d’un enfant âgé de 2 ans qui a été hospitalisé pour une pneumopathie interstitielle, associée à une otorrhée bilatérale. L’examen a montré un comblement des 2 conduits auditifs externes et des lésions cutanées squameuses. La biopsie a conclu à une histiocytose langerhansienne. Malgré la chimiothérapie, l’enfant est décédé après 11 mois.Mots-clés : Histiocytose langerhansienne, atteinte auriculaire

    La mucormycose nasosinusienne: Diagnostic et modalites therapeutiques

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    La mucormycose est une infection fongique rare qui touche essentiellement les sujets immunodéprimés et notamment diabétiques. La localisation de cette maladie est surtout nasosinusienne. Son pronostic reste mauvais malgré le développement des moyens de prise en charge. Nous rapportons deux cas de mucormycose nasosinusienne à travers lesquels nous discutons les aspects cliniques et radiologiques, ainsi que les moyens thérapeutiques de cette maladie. Il s’agit d’un homme et d’une femme âgés respectivement de 56 et 52 ans. Le premier était diabétique et la deuxième insuffisante rénale. L’évolution était lente dans le premier cas et très rapide dans le deuxième. Le diagnostic était dans les deux cas histologique. L’évolution était, dans le premier cas, favorable après traitement associant débridement chirurgical et amphotéricine B, et dans le second rapidement fatale. Conclusion : La mucormycose nasosinusienne est une affection grave dont le pronostic peut être mauvais malgré le traitement.Mots clés : Infection fongique, mucormycose rhinocérébrale, zygomycètes

    Physico-Chemical Characterization of Water and Soil of the M’nasra region in the Gharb plain (Northwest Morocco)

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    The aim of this work is to carry out an evaluation of the quality of agricultural soils and water in the irrigated area of the M’nsara region in the Gharb plain (Northwest Morocco) with the goal of describing the degree of degradation of natural resources and improve the sustainability of the environment and irrigated farming systems of the region through optimal management of these resources. Eighteen water and nineteen soil samples were collected based on existing soil and piezometric maps of the irrigated areas, distributed into 3 different zones: A, B, and C. Characterizations of the main parameters of soil and irrigation water quality were made. Irrigation water salinity varies between 0.5 and 1.3 dS/m. The irrigated soils from the groundwater have shown a secondary salinization superior to that of irrigated soils by the waters of the dam. Cultivated soils present a salinity that reaches 1.90 dS/m in some areas. The results show that 68.4% of the soil samples are poor to moderately poor in organic matter. The sodium adsorption ratio (SAR) shows a minimal risk to accumulate sodium in the soil with 16.7% is slightly alkaline. The soils are weakly to moderately basic and represent respectively 73.7 and 10.5 % of the study area. Potassium and available phosphorus have very low values in the majority of soils which will have a negative impact on the environment. The spatialization of these parameters was performed by the determinsitc method of inverse distance weighted (IDW). In order to delineate areas that are a priori subject to environmental degradation in order to understand the effect of agricultural intensification on the sustainability of natural resources, taking into account the type of management water irrigation in the arid region

    Cystic echinococcosis in slaughtered domestic ruminants from Tunisia

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    A total of 10,818 domestic ruminants (3913 cattle, 2722 sheep, 3779 goats, 404 dromedaries) slaughtered in various abattoirs in Tunisia between 2003 and 2010 were examined for the presence of Echinococcus granulosus hydatid cysts. The prevalence of cystic echinococcosis (CE) was 16.42% in sheep, 8.56% in cattle, 5.94% in dromedaries and 2.88% in goats. CE prevalence increased with age according to an asymptotic model and there was evidence of variation in infection pressure depending on the region of Tunisia where the animals were slaughtered. Cattle appeared to have the highest infection pressure of the species examined. The mean intensity of hepatic cysts was higher than that of pulmonary cysts in all species. The highest mean intensity of infection with E. granulosus larvae was observed in cattle (18.14) followed by sheep (9.58), goats (2.31) and dromedaries (2.12). The abundance of infection increased in a linear fashion with age in all animal species. Cyst abundance varied with species of animal and district of Tunisia. Cysts from dromedaries were more fertile (44.44%) than those from sheep (30.25%), goats (30.32%) and cattle (0.95%). The viability of the protoscoleces from fertile cysts from cattle (78.45%) was higher than those from sheep (70.71%) and camels (69.57%). The lowest protoscolex viability was recorded for hydatid cysts from goats (20.21%). This epidemiological study confirms the importance of CE in all domestic ruminant species, particularly in sheep, throughout Tunisia and emphasizes the need to interrupt parasite transmission by preventive integrated approaches in a CE control programm
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