9 research outputs found

    A Statistical Analysis of Size, Shape and Tensile Properties of Fibres Extracted from Date Palm (Phoenix Dactylifera L.) Rachis

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    Algeria is the largest country in Africa by in terms of land area, which makes it contain large quantities of agricultural residues. The aim of this study is the valorisation of the huge amount of agricultural residue of date palm rachis available in Algeria to be used as reinforcement in bio-composite materials for various industrial applications. The analysis of the morphology of the of the date palm rachis cross-section allowed us to identify two main types of fibres according to their microstructure: vascular bundles and fibre strands. The chemical and molecular structure analysis of the date palm rachis fibres was examined by Fourier transform infrared spectroscopy (FTIR). The tensile properties of the fibre extracted were investigated under tensile loading test. The experimental results obtained for the tensile strength, Young’s modulus and strain at break of the fibres have been analysed, because of their dispersion, using three-parameter and two-parameter Weibull statistical laws. The tensile strength and Young’s modulus of the fibre strand were found to be about than four times higher than for the vascular bundle and their predicted model was determined. The tensile properties obtained for the investigated fibre were compared with other lignocelluloses fibres, existing in the literature, and it shows its great potential for use as reinforcement in bio-composite materials

    Analysis of factors that contribute to treatment failure in patients with community-acquired pneumonia

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    To determine the causes of treatment failure and to evaluate the prognostic factors in patients hospitalized for community-acquired pneumonia, a prospective, observational study of 228 adult patients hospitalized for a community-acquired pneumonia in the University Hospital of Geneva and the La Chaux-de-Fonds Community Hospital, Switzerland, was conducted. The percentage of patients who failed to improve (as defined by guidelines of the Infectious Disease Society of America) and the causes of treatment failure were assessed, and patients who failed to improve under antimicrobial therapy were compared with those who did improve. In the 54 (24%) patients who failed to improve, a mean increase in length of hospitalization of 4 days was observed. Most causes of treatment failure could be attributed to host factors (61%) rather than to the pathogen (16%) or to an inappropriate antibiotic regimen (3%). After adjusting for potentially confounding variables, concomitant neoplasia (OR 3.25; 95%CI 1.11-9.56), neurological disease (OR 2.34; 95%CI 1.07-5.13), and aspiration pneumonia (OR 2.97; 95%CI 29-6.86]) were associated with failure to improve, whereas monocytosis improved prognosis (OR 0.40; 95%CI 0.20-0.80). Almost one out of four patients hospitalized for community-acquired pneumonia failed to respond to empirical antibiotic treatment. Aspiration pneumonia, concomitant neoplasia, and neurological disease were factors positively associated with failure to improve, whereas monocytosis was linked to a better prognosis

    Endovaporisation au laser KTP-80 de l’hypertrophie symptomatique de la prostate chez les patients sous médication antithrombotique

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    Our population is ageing along with the rate of cardiovascular pathologies, which frequently require administration of antithrombotic treatments. Consequently, prostatic surgery becomes increasingly delicate. Thus per- and post-operative macroscopic hematuria contributes significantly to the duration of hospitalization and the morbidity of conventional surgery of symptomatic prostate hypertrophy. Moreover, these patients require transient suspension of their anticoagulation or anti-aggregation treatment. The recent KTP-80 laser limits post-operative hematuria and allows to operate on the growing population of patients under antiagregant and/or anticoagulant therapy. We review in these patients the operative modalities and the results of this surgery, in comparison with transurethral resection of the prostate

    Temperature-Tuning of Optical Properties and Molecular Aggregation in AnE-PVstat Copolymer Solution

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    The correlation between the optical and morphological properties of an anthracene-containing poly­(phenylene ethynylene)-<i>alt</i>-(phenylenevinylene) statistical copolymer (AnE-PVstat) in solution has been investigated. As a function of temperature, the molecular aggregation in chloroform/chlorobenzene (CF:CB) solution was examined by means of absorbance and photoluminescence measurements. The study of the evolution of the 0–0 to the 0–1 photoluminescence (PL) ratio with temperature in the framework of the HJ-aggregate model unveiled the presence of both H- and J-like behaviors at room temperature. Upon increasing temperature, the interchain intermolecular coupling decreases, leading to a dissociation of H-aggregates. Hence, molecular torsions are facilitated, polymer planarity is reduced, and the intrachain electronic coupling decreases
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