Dosage des métaux lourds dans les

Objectifs : Parmi les métaux lourds présents dans notre environnement, certains sont toxiques; absorbés par les plantes, ils s’accumulent dans les tissus et s’éliminent lentement; d’autres, les oligoéléments, indispensables à l’organisme, deviennent toxiques à dose forte. Dans le genre Zygophyllum, trois espèces sahariennes Z. geslini, Z. album, et Z. sp., sont employées quotidiennement en médecine traditionnelle comme antidiabétiques; cette utilisation répétée nous a incités à effectuer un dosage des métaux lourds (plomb, cadmium, fer, arsenic, manganèse, zinc, chrome, cuivre). Méthodes : – Pour chaque plante, une prise d’essai de 2 g de poudre de tige, racine, feuille, fruit, est minéralisée (méthode de Kjeldall). L’opération est effectuée deux fois. – Chaque minéralisât est analysé par injection dans le four (20 µL du minéralisât dilué au vingtième et 5 µL de modificateur de matrice). Pour chaque élément, une courbe d’étalonnage est réalisée. – La lecture s’effectue dans les conditions analytiques identiques à celles utilisées pour établir la courbe d’étalonnage. La concentration de l’échantillon est directement lue sur les courbes respectives. – Dosage par spectrophotométrie; appareil simple (fer) ou absorption atomique (plomb, cadmium, manganèse, arsenic, nickel). Résultats : Sous forme de tableaux, ils sont exprimés en µg/g, pour les trois espèces. Conclusions : Les valeurs les plus élevées sont : le plomb, le cadmium, le manganèse et le nickel. Le taux de chrome avoisine celui de la levure de bière, considérée comme une bonne source. La valeur en zinc dans Z. geslini est importante. Le fer est faiblement représenté

Characterization of polylactic acid green composites and its biodegradation in a bacterial environment

International audienc

Effect of alfa fiber loading on the mechanical, physical and dielectric properties of epoxy-amine composite

International audienceIn this work, a varied content of alfa fiber was used as reinforcement and epoxy resin as matrix material. In order to eliminate the amorphous part of the alfa fiber, the fibers are treated with 5% of sodium hydroxide solution and their weight fraction is varied between 10% and 30%. Dielectric and water characteristics of different content of untreated and alkali treated alfa reinforced epoxy matrix is carried out in order to determine the role of cellulosic fibers in electrical field. Then, the Fourier transform infrared (FTIR) is employed to analyze the chemical structure of epoxy resin before and after curing with amine hardener. FTIR and Differential Scanning Calorimetry analysis confirm that epoxy resin is completely cured with amine hardener at room temperature. For composites loaded with 30% treated and untreated alfa fiber, a decrease in tensile and dielectric properties has been obtained, this may be related to the random distribution of alfa fiber in the epoxy matrix. Scanning electron microscopy analysis highlight the microstructure of epoxy matrix and its composites. The bio composites elaborated on the basis of alfa fiber and epoxy matrix have good physical and dielectric properties can be applied in different fields

Evaluation and Characterization of Randomly Oriented Alfa Fibers Reinforced Epoxy‐Amine Composites

International audienceThe main objective of this research is to examine the effect of various fibercontent and alkali treatment on the thermal and mechanical properties of alfa fiber reinforced epoxy-amine matrix-based composites. The fibers are treated with 5% of sodium hydroxide solution and their weight fraction is varied between 10% and 30%. The flexural test is carried out to investigate the mechanical properties of composites and the results show that all composites exhibit higher mechanical properties than the neat epoxy-amine. The decline of flexural behavior of all composites with the increasing of the filler (30%) content is due probably to the random dispersion of the fibers in the epoxy resin

Anvillea garcinii extract inhibits the oxidative burst of primary human neutrophils

International audienceAbstractBackgroundAnvillea garcinii Coss. & Durieu (Anv) plant is used as a traditional North African medicine against several diseases associated with inflammation. At inflammatory sites, reactive oxygen species (ROS) produced in excess by activated phagocyte NADPH oxidase (NOX2) can accentuate inflammatory responses. Thus, we investigated if Anv-water soluble polysaccharides could modulate primary human neutrophil oxidative burst in vitro.MethodsHuman neutrophils were isolated from fresh whole blood and O2.- generation was measured by cytochrome c reduction assays. Western blots were used to analyse the translocation of PKC, p47phox (a key component of NOX2 activity) to neutrophil plasma membrane. Also, myeloperoxidase (MPO) release in the extracellular medium was studied by western blots. Flow cytometric analysis was used to detect CD11b membrane expression.ResultsWater soluble polysaccharides from Anv dose-dependently inhibited N-formyl-methionyl-leucyl-phenylalanine (fMLF)- and phorbol myristate acetate (PMA)-induced O2.- generation by human neutrophils. Moreover, Anv-polysaccharides strongly inhibited PMA-induced PKCβ and p47phox translocation to membranes and p47phox phosphorylation on Ser328, a main PKC target. In contrast, polysaccharides extract from Zygophyllum gaetulum plant, which is also used as a traditional North African medicine against inflammatory diseases, was ineffective on this PKCβ-p47phox pathway. Further, Anv inhibited important neutrophil degranulation markers corresponding to myeloperoxidase (MPO) release and CD11b membrane expression.ConclusionThe process of down-regulating NADPH oxidase by polysaccharides extracts from Anv provides new insights into the mechanism of Anv’s anti-inflammatory actions

Abstracts of 1st International Conference on Computational & Applied Physics

This book contains the abstracts of the papers presented at the International Conference on Computational & Applied Physics (ICCAP’2021) Organized by the Surfaces, Interfaces and Thin Films Laboratory (LASICOM), Department of Physics, Faculty of Science, University Saad Dahleb Blida 1, Algeria, held on 26–28 September 2021. The Conference had a variety of Plenary Lectures, Oral sessions, and E-Poster Presentations. Conference Title: 1st International Conference on Computational & Applied PhysicsConference Acronym: ICCAP’2021Conference Date: 26–28 September 2021Conference Location: Online (Virtual Conference)Conference Organizer: Surfaces, Interfaces, and Thin Films Laboratory (LASICOM), Department of Physics, Faculty of Science, University Saad Dahleb Blida 1, Algeria