Oleuropein and Antibacterial Activities of Olea europaea L. Leaf Extract

In this study, we reported the determination of phenolic compounds in olive leaves by reversed phase HPLC/DAD and the evaluation of their in vitro activity against several microorganisms. These organisms might however, be causal agents of human intestinal and respiratory tract infections. Extract of the leaves of two varieties of Olea europaea L. (Chemlel and Dathier) was investigated for antibacterial activity against four pathogenic bacteria. Leaves extract was prepared using water and methanol (20/80) in a cold extraction process. The tested bacteria were Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus .The extracts were found to be effective against all isolates tests. Ethanolic extract at a concentration of 100 % presented the highest potential of inhibiting variety of Dathier against S.aureus .This is with an inhibition zone of 17.49 mm and 15.66 mm for the variety Chemlel against S.aureus. The high Oleuropein content and the important antibacterial activities of olive leaves extract could be useful sources for industrial extraction and pharmacological application

Capabilities of the multi-mechanism model in the prediction of the cyclic behavior of various classes of metals

International audienceThe paper deals with an evaluation of the multi-mechanism (MM) approach capabilities in the prediction of the cyclic behavior of different classes of metallic materials. For this objective, the tests detailed in (Taleb, Int J Plast 43:1–19, 2013a) have been simulated here by the MM model. In these tests, six alloys were considered: two ferritic steels (35NCD16 and XC18), two austenitic stainless steels (304L and 316L), one “extruded” aluminum alloy (2017A) and one copper-zinc alloy (CuZn27). The specimens have been subjected to proportional and non-proportional stress as well as the combination of stress and strain control at room temperature. The identification of the material parameters has been carried out using exclusively strain controlled experiments under proportional and non-proportional loading paths performed in the present study for each material. The model may describe a large number of phenomena with twenty five parameters in total but, it appears that for a given material under the adopted conditions, the activation of all parameters may be not necessary. Our attention was focused mainly on the capabilities to predict correctly the cyclic accumulation of the inelastic strain including the shape of the hysteresis loops. The comparison between test responses and their predictions by the MM model are generally satisfactory with relatively small number of material parameters (between eight and thirteen according to the material). One can also highlight the capability of the MM model to describe a transient ratcheting without activation of the dynamic recovery term in the kinematic variables. Finally, the MM model deserves improvement for a better description of the cyclic behavior of anisotropic materials