Évaluation de l’activité biologique des feuilles de l’olivier sauvage et cultivé

L’olivier est très répondu en Algérie et largement utilisé par les populations locales. Les propriétés médicinales de l’olivier sont surtout attribuées aux feuilles. Dans le cadre de la valorisation des ressources naturelles, nous avons essayé dans cette étude de contribuer à la connaissance de certains effets biologiques des feuilles de l’olivier sauvage (Olea europea subsp europae var. sylvestris) et de l’olivier cultivé (Olea europea subsp europea var. sativa) récoltés dans la wilaya de Tizi-Ouzou. L’utilisation de ces dernières en phytothérapie par la population locale se fait à l’état naturel (infusion ou décoction). Les feuilles sont utilisées pour leur effet hypoglycémiant et hypotenseur à des doses journalières de 40 à 50g. L’extraction des polyphénols totaux a été faite par macération au méthanol. Le rendement était de 38,74% pour l’olivier sauvage et 35, 72% pour le cultivé. L’évaluation de l’activité antioxydante des polyphénols totaux par la méthode de DPPH révèle une valeur de CI50 de 0.24mg/mL. Ceci classe les polyphénols de l’olivier comme antioxydant puissant. L’administration d’un volume de 2mL de tisane, préparée à partir de 50 g de feuille, à des rats rendus diabétiques par une dose de 150mg/kg d’alloxane a provoqué une diminution très hautement significative (P ˂ 0.0005) de la glycémie et des variations non significative (p ˃ 0.05) de cholestérolémie et de triglycérides.Mots-clés : Olea europea, polyphénols, alloxane, antioxydant, antihyperglycémiant.Evaluation of the biological activity of the leaves of wild and cultivated oliveThe olive tree is omnipresent in Algeria and widely used by local people. The medicinal properties of the olive tree are mostly attributed to the leaves. As part of the development of natural resources, we tried in this study contribute to the knowledge of some biological effects of leaves of wild olive (Olea europaea subsp europae var . Sylvestris) and cultivated (Olea europea subsp europea var. sativa) collected in the wilaya of Tizi Ouzou. The use of herbal medicine in the past by the local population is in its natural state (infusion or decoction). The leaves are used for their hypoglycemic and hypotensive effect at daily doses of 40 to 50g. The extraction of total polyphenols was made by maceration with methanol. The yield was 38.74% for the wild olive and 35, 72% for cultivated. The evaluation of the antioxidant activity of total polyphenols by the DPPH method reveals an IC50 value of 0.24mg/mL. This class of olive polyphenols as a potent antioxidant. The administration of a volume of 2 ml of tea, prepared from 50 g of leaf in diabetic rats with a dose of 150mg/kg of alloxan has caused a very highly significant (P ˂ 0.0005) of the glucose and insignificant changes (p ˃ 0.05) cholesterol and triglycerides.Keywords : Olea europea, polyphenols, alloxan, antioxidant, antihyperglycemic

Tribes, state, and technology adoption in arid land management, Syria:

Arid shrub-lands in Syria and elsewhere in West Asia and North Africa are widely thought degraded. Characteristic of these areas is a preponderance of unpalatable shrubs or a lack of overall ground cover with a rise in the associated risks of soil erosion. Migrating pastoralists have been the scapegoats for this condition of the range. State steppe interventions of the last forty years have reflected this with programs to supplant customary systems with structures and institutions promoting western grazing systems and technologies. Principal amongst the latter has been shrub technology, particularly Atriplex species, for use in land rehabilitation and as a fodder reserve. This paper deconstructs state steppe policy in Syria by examining the overlap and interface of government and customary legal systems as a factor in the history of shrub technology transfer in the Syrian steppe. It is argued that the link made between signs of degradation and perceived moribund customary systems is not at all causal. Indeed, customary systems are found to be adaptive and resilient, and a strong influence on steppe management and the fate of technology transfer initiatives. Furthermore, developments in rangeland ecology raise questions about claims for grazing-induced degradation and call for a reinterpretation of recent shifts in vegetation on the Syrian steppe. Given the ineffectiveness of past state interventions, and in view of renewed understanding of customary systems and rangeland ecology, decentralization and some devolution of formal management responsibility is likely to be a viable and an attractive option for policymakers.

Analysis Techniques of Polymeric Encapsulant Materials for Photovoltaic Modules: Situation and Perspectives

AbstractThe properties of the encapsulant are critical to the long-term performance of photovoltaic (PV) modules under the influence of sunlight including UV, elevated temperature, humidity and diffusion of oxygen. Encapsulation process represents about 40% of the whole PV module cost. The introduction of new non-EVA encapsulant material type ″Low-Cost, High-Performance″ should provide a solution to outdoor yellowing degradation problems. The emerging encapsulant materials exhibit a good compatibility with emerging PV solar cells for long term durability. This new generation of encapsulant materials has the advantage to improve the PV module performances and long term durability for specific climate like desert regions. This scientific contribution presents an overview of the different encapsulant materials currently on the market, the general requirements of the emerging encapsulant materials and characterizations techniques for degradation, diagnostic and reliability lifetime estimation in the framework of Algerian renewable energy strategy

Supramolecular Interactions Involved in the Solid State Structure of N,N\u27-[bis(pyridin-2-yl)formylidene]ethane-1,2-diamine

The structure of the symmetrical Schiff base, N,N\u27-[bis(pyridin-2-yl)formylidene]ethane-1,2-diamine (bpfd) has been characterized by single crystal X-ray diffraction. The non-covalent supramolecular chemistry involved in the crystal structure of this ligand has been carefully investigated. The structure adopted different motifs of nitrogen-hydrogen interactions that led to the formation of centrosymmetric dimers. In addition, edge-edge and face-face nitrogen-nitrogen interactions were ob-served and reported. The Schiff base (bpfd) ligand crystallizes in a monoclinic space group C12/c1 with a = 19.128(2) Å; b = 5.8776(6) Å; c = 13.1403(15) Å; α = 90o; β = 121.970o(4); γ = 90o and z = 4. This structure is an example of compounds with many symmetry-independent molecules in the asymmetric unit cell (Z > 2)

Hubble Tarantula Treasury Project. III. Photometric Catalog and Resulting Constraints on the Progression of Star Formation in the 30 Doradus Region

We present and describe the astro-photometric catalog of more than 800,000 sources found in the Hubble Tarantula Treasury Project (HTTP). HTTP is a Hubble Space Telescope (HST) Treasury program designed to image the entire 30 Doradus region down to the sub-solar (~0.5 solar masses) mass regime using the Wide Field Camera 3 (WFC3) and the Advanced Camera for Surveys (ACS). We observed 30 Doradus in the near ultraviolet (F275W, F336W), optical (F555W, F658N, F775W), and near infrared (F110W, F160W) wavelengths. The stellar photometry was measured using point-spread function (PSF) fitting across all the bands simultaneously. The relative astrometric accuracy of the catalog is 0.4 mas. The astro-photometric catalog, results from artificial star experiments and the mosaics for all the filters are available for download. Color-magnitude diagrams are presented showing the spatial distributions and ages of stars within 30 Dor as well as in the surrounding fields. HTTP provides the first rich and statistically significant sample of intermediate and low mass pre-main sequence candidates and allows us to trace how star formation has been developing through the region. The depth and high spatial resolution of our analysis highlight the dual role of stellar feedback in quenching and triggering star formation on the giant HII region scale. Our results are consistent with stellar sub-clustering in a partially filled gaseous nebula that is offset towards our side of the Large Magellanic Cloud.Comment: 20 pages, 22 Figures, 3 Tables, Photometric Catalogs and Mosaiced images will be available for download upon publication, accepted for publication on ApJ