417 research outputs found

    Geochemical characterization the waters of Foggaras the Continental Intercalary Aquifer of Timinoune region (south west Algeria)

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    The study of the Continental Intercalary (C.I) groundwater of the region of Timimoune (southwestern Algeria), based on physico-chemical data (major elements), allowed to understand the geochemistry of foggaras water. The aquifer is contained in the formations of the Lower Cretaceous (Albian and Barremian). The waters are strongly mineralized with an average value 2g / l.The waters have a clear predominance of facies chlorinated-sodium. The risk is high to excessive soil salinization, and the risk of medium alkalinity to very high. Statistical analysis led us to reach two conclusions, the first is that, variable electrical conductivity (EC), dry residue (RS), Na+, Ca2+, Cl-, SO4 --, mineralization, are best correlated and responsible the signing of the mineral load of water, the second is that the nitrate ion (NO3-) opposite to the above-mentioned variables mark its anthropogenic origin. Keywords: Continental Intercalary, mineralization, salinity, PCA, Nitrat

    Chemical polymorphism of essential oils from populations of Laurus nobilis grown on Tunisia, Algeria and France.

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    The compositions of the essential oils isolated from the aerial parts of tree Mediterranean populations of Laurus nobilis L. collected during the flowering phase on Tunisia, Algeria and France, were studied by GC and GC-MS. The analysis has allowed identifying 54 components. The main components were 1,8-cineole, α-terpinyl acetate (10-18.6%), methyl eugenol (10-22.1%), sabinene (1.2-8%), eugenol (1.2-11.7%) α-pinene (tr-4.5%) and β-pinene (0.4-4.2%). The monoterpene fraction was dominant in all the oils analysed and consisted mainly of oxygenated monoterpenes. The oils from the tree populations studied showed a clear chemical polymorphism. The principal component and the hierarchical cluster analyses separated the Laurus nobilis leaf essential oils into three groups

    Régénération de la suberaie tunisienne : état des lieux, contraintes et avancées techniques

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    Alors que la situation des suberaies tunisiennes est extrêmement inquiétante, avec une perte de la moitié de sa surface en 80 ans, la régénération naturelle est pratiquement inexistante. C’est pourquoi les services forestiers tunisiens ont mis en place des essais proposant d’autres techniques de reconstitution artificielle, notamment la plantation. Leur réussite est toutefois fortement liée aux conditions climatiques et aux activités humaines

    Removal of methylene blue with a highly effective hydroxyapatite-silica nanocomposite

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    Two Hydroxyapatite-silica nanocomposite adsorbent (HApS220 and HApS230) were successfully synthesized using sol-gel technique. The samples were characterized by powder X-ray diffraction (XRD), Infrared spectroscopy (IR), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS), which confirmed the formation of a Hydroxyapatite-silica nanocomposite. The synthesized powders were then used for adsorption of methylene blue (MB). Both compounds possessed high absorption capacities, the adsorption equilibrium time is around 10 min. HApS230 sample shows higher adsorption capacity compared to HApS220. Furthermore, isotherm studies show that the adsorption used is an ion exchange process and that Temkin isotherm describes the adsorption better compared to the Langmuir and Freundlich and Dubinin-Radushkevich isotherms. Kinetics studies confirm that the adsorption follow the pseudo-second order model and chemisorption mechanism. Thermodynamics’ studies confirm that the adsorption of MB on HApS samples is a spontaneous endothermic process. The average removal effectiveness of MB reached about 89.02% (6.389 mg/g adsorption capacity) and 91.36% (6.55 mg/g adsorption capacity) for HApS220 and HApS230 respectivel

    The Chemistry of Griseofulvin

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    The FlbA-regulated predicted transcription factor Fum21 of <i>Aspergillus niger</i> is involved in fumonisin production

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    Aspergillus niger secretes proteins throughout the colony except for the zone that forms asexual spores called conidia. Inactivation of flbA that encodes a regulator of G-protein signaling results in colonies that are unable to reproduce asexually and that secrete proteins throughout the mycelium. In addition, the ΔflbA strain shows cell lysis and has thinner cell walls. Expression analysis showed that 38 predicted transcription factor genes are differentially expressed in strain ΔflbA. Here, the most down-regulated predicted transcription factor gene, called fum21, was inactivated. Growth, conidiation, and protein secretion were not affected in strain Δfum21. Whole genome expression analysis revealed that 63 and 11 genes were down- and up-regulated in Δfum21, respectively, when compared to the wild-type strain. Notably, 24 genes predicted to be involved in secondary metabolism were down-regulated in Δfum21, including 10 out of 12 genes of the fumonisin cluster. This was accompanied by absence of fumonisin production in the deletion strain and a 25% reduction in production of pyranonigrin A. Together, these results link FlbA-mediated sporulation-inhibited secretion with mycotoxin production

    Physicochemical study of magnesium zinc codoped-hydroxyapatite

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    Mg-Zn-doped hydroxyapatites in the system Ca9.4-xMg0.6Znx(PO4)6(OH)2 (x= 0, 0.1, 0.2, 0.4 and 0.6) were synthesized via sol-gel method. The obtained powder was calcined at 600°C and 700°C. X-ray diffraction (XRD) patterns and Infra-Red (IR) spectra confirmed the formation of pure hydroxyapatite up to 2% Zn content (a trace of β-pyrophosphate is detected for x=0), while a mixture of hydroxyapatite and β-TCP was formed for 4 mol%. With 6 mol%, only β-TCP formed. Moreover, at 700°C, all powders turned to be composed of solely β-TCP. The unit cell constants have also been calculated and match well with hexagonal (P63/m) hydroxyapatite

    The ThomX project status

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    Work supported by the French Agence Nationale de la recherche as part of the program EQUIPEX under reference ANR-10-EQPX-51, the Ile de France region, CNRS-IN2P3 and Université Paris Sud XI - http://accelconf.web.cern.ch/AccelConf/IPAC2014/papers/wepro052.pdfA collaboration of seven research institutes and an industry has been set up for the ThomX project, a compact Compton Backscattering Source (CBS) based in Orsay - France. After a period of study and definition of the machine performance, a full description of all the systems has been provided. The infrastructure work has been started and the main systems are in the call for tender phase. In this paper we will illustrate the definitive machine parameters and components characteristics. We will also update the results of the different technical and experimental activities on optical resonators, RF power supplies and on the electron gun
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