1,307 research outputs found
Ăvaluation de lâactivitĂ© biologique des feuilles de lâolivier sauvage et cultivĂ©
Lâolivier est trĂšs rĂ©pondu en AlgĂ©rie et largement utilisĂ© par les populations locales. Les propriĂ©tĂ©s mĂ©dicinales de lâolivier sont surtout attribuĂ©es aux feuilles. Dans le cadre de la valorisation des ressources naturelles, nous avons essayĂ© dans cette Ă©tude de contribuer Ă la connaissance de certains effets biologiques des feuilles de lâolivier sauvage (Olea europea subsp europae var. sylvestris) et de lâolivier cultivĂ© (Olea europea subsp europea var. sativa) rĂ©coltĂ©s dans la wilaya de Tizi-Ouzou. Lâutilisation de ces derniĂšres en phytothĂ©rapie par la population locale se fait Ă lâĂ©tat naturel (infusion ou dĂ©coction). Les feuilles sont utilisĂ©es pour leur effet hypoglycĂ©miant et hypotenseur Ă des doses journaliĂšres de 40 Ă 50g. Lâextraction des polyphĂ©nols totaux a Ă©tĂ© faite par macĂ©ration au mĂ©thanol. Le rendement Ă©tait de 38,74% pour lâolivier sauvage et 35, 72% pour le cultivĂ©. LâĂ©valuation de lâactivitĂ©Â antioxydante des polyphĂ©nols totaux par la mĂ©thode de DPPH rĂ©vĂšle une valeur de CI50 de 0.24mg/mL. Ceci classe les polyphĂ©nols de lâolivier comme antioxydant puissant. Lâadministration dâun volume de 2mL de tisane, prĂ©parĂ©e Ă partir de 50 g de feuille, Ă des rats rendus diabĂ©tiques par une dose de 150mg/kg dâalloxane a provoquĂ© une diminution trĂšs hautement significative (P Ë 0.0005) de la glycĂ©mie et des variations non significative (p Ë 0.05) de cholestĂ©rolĂ©mie et de triglycĂ©rides.Mots-clĂ©s : Olea europea, polyphĂ©nols, alloxane, antioxydant, antihyperglycĂ©miant.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 Ë 0.0005) of the glucose and insignificant changes (p Ë 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 âłLow-Cost, High-Performanceâł 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) Ă
; b = 5.8776(6) Ă
; c = 13.1403(15) Ă
; α = 90o; ÎČ = 121.970o(4); Îł = 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
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