341 research outputs found

    Constraints on alluvial clay mineral assemblages in semiarid regions. The Souss Wadi Basin (Morocco, Northwestern Africa)

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    Illite, chlorite and kaolinite, resulting directly from substratum weathering, dominate the clay assemblages recorded in altered rocks and soils of the Souss Wadi watershed. Nevertheless, the transformation and neoformation of diverse clay minerals, which is mainly controlled by changing climatic, lithological and topographic conditions, enables one to establish three distinctive source areas. High altitude, largely watered zones where chlorite is transformed into vermiculite; middle altitude drier areas where more pronounced seasonal contrast induces the transformation of chlorite into chlorite-smectite mixed layer; finally, semiarid low altitude zones with gentle slopes where the weathering of carbonate-dominated substrata, evaporation and chemical concentration result in smectite and palygorskite neoformation. These minerals, which result from transformation and neoformation, provide suitable environmental indicators and local to zonal tracers of sediment contribution. Nevertheless, the original clay mineral assemblages undergo a significant homogenisation due to the destruction of most of the transformed and neoformed minerals during fluvial transport. As a consequence, inherited clay minerals (illite, chlorite and kaolinite) usually dominate the assemblages recorded in the downstream alluvial sediments. The clay assemblages recorded in different tributary wadi alluvial deposits reflect major sediment contribution from the High-Atlas and the older alluvial plain deposits affected by intensive erosion. On the other side, Anti-Atlas contribution is lesser as a consequence of its wide tableland topography and the widespread outcropping of karstified carbonate rocks, which enhance water infiltration and preclude sediment supply

    Chondrocalcinose articulaire rĂ©vĂ©latrice d’une hypercalcĂ©mie hypocalciurique familiale: Ă  propos d’une observation

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    L'hypercalcémie hypocalciurique familiale (HHF) est une maladie bénigne à transmission autosomique dominante, caractérisée par une hypercalcémie persistante béhigne, une hypocalciurie, et des concentrations de  parathormone (PTH) normales ou modérément élevées, sans complication secondaire à l'hypercalcémie. Nous rapportons l'observation d'un patient ayant présenté une chondrocalcinose articulaire révélatrice d'une HHF. A travers cette observation nous essayons de décrire les aspects épidémiologiques, les caractéristiques cliniques, et paracliniques de cette association

    Efficiency improvement of LDO ouput based linear regulator with supercapacitor energy recovery - a versatile new technique with an example of a 5v to 1.5 v version

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    Supercapacitors are used in various industrial applications and the supercapacitors technology is gradually progressing into a mature state. Common applications of supercapacitors are in electric vehicles, hybrid electric vehicles, uninterruptible power supply (UPS) and in portable devices such as cellular phones and laptops. The capacitance values range from fractional Farads to few thousand Farads and their continuos DC voltage ratings are from 2V to 6V. At University of Waikato, a team works on using supercapacitors for improving the efficiency of linear voltage regulators. In particular, this patented technique aims at combining off the shelfs LDO ICs and a supercapacitor array for improving end to end efficiency of linear regulator. My work is aimed at developing the theoretical background and designing prototype circuitry for a voltage regulator for the case of unregulated input supply is more than 3 times of the minimum input voltage requirement of the LDO which is applicable for a 5V to 1.5V regulator. Experimental results are indicated with future suggestions for improvement

    The thick-thin decomposition and the bilipschitz classification of normal surface singularities

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    We describe a natural decomposition of a normal complex surface singularity (X,0)(X,0) into its "thick" and "thin" parts. The former is essentially metrically conical, while the latter shrinks rapidly in thickness as it approaches the origin. The thin part is empty if and only if the singularity is metrically conical; the link of the singularity is then Seifert fibered. In general the thin part will not be empty, in which case it always carries essential topology. Our decomposition has some analogy with the Margulis thick-thin decomposition for a negatively curved manifold. However, the geometric behavior is very different; for example, often most of the topology of a normal surface singularity is concentrated in the thin parts. By refining the thick-thin decomposition, we then give a complete description of the intrinsic bilipschitz geometry of (X,0)(X,0) in terms of its topology and a finite list of numerical bilipschitz invariants.Comment: Minor corrections. To appear in Acta Mathematic

    Virulence properties and random amplification of polymorphic DNA (RAPD) fingerprinting of Candida albicans isolates obtained from Monastir dental hospital, Tunisia

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    Genotypic and phenotypic characterization as well as studies on the virulence factors of Candida albicans isolates obtained from oral cavity of patients was carried out using random amplified polymorphic DNA (RAPD) fingerprinting and epithelial cells adherence assay, respectively. RAPD patterns revealed the presence of 13 C. albicans genotypes separated into two clusters at 75% ofsimilarity when they were combined. Results also showed the presence of haemolytic protease activity as virulence factors with 88% of the C. albicans strains been able to adhere to Caco-2 cells and only 64% to Hep-2. RAPD-polymerase chain reaction (PCR) is a molecular tool used to differentiate the isolates into various genotypes based on their virulence properties.Key words: Candida albicans, stomatitis, random amplified polymorphic DNA, Hep-2, Caco-2 cells

    Separation of instrumental and astrophysical foregrounds for mapping CMB anisotropies

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    We address the extended problem of component separation for CMB applications when a mixture of both astrophysical and instrumental components are present in the observations, and show how standard methods can be adapted to handle this more complex inversion problem.Comment: 12 pages, 5 figures, submitted to MNRA

    Phytochemical Analysis, Antioxidant, and Antimicrobial Activities of Ducrosia flabellifolia: A Combined Experimental and Computational Approaches

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    Ducrosia flabellifolia Boiss. is a rare desert plant known to be a promising source of bioactive compounds. In this paper, we report for the first time the phytochemical composition and biological activities of D. flabellifolia hydroalcoholic extract by using liquid chromatography-electrospray tandem mass spectrometry (ESI-MS/MS) technique. The results obtained showed the richness of the tested extract in phenols, tannins, and flavonoids. Twenty-three phytoconstituents were identified, represented mainly by chlorogenic acid, followed by ferulic acid, caffeic acid, and sinapic acid. The tested hydroalcoholic extract was able to inhibit the growth of all tested bacteria and yeast on agar Petri dishes at 3 mg/disc with mean growth inhibition zone ranging from 8.00 ± 0.00 mm for Enterococcus cloacae (E. cloacae) to 36.33 ± 0.58 mm for Staphylococcus epidermidis. Minimal inhibitory concentration ranged from 12.5 mg/mL to 200 mg/mL and the hydroalcoholic extract from D. flabellifolia exhibited a bacteriostatic and fungistatic character. In addition, D. flabellifolia hydroalcoholic extract possessed a good ability to scavenge different free radicals as compared to standard molecules. Molecular docking studies on the identified phyto-compounds in bacterial, fungal, and human peroxiredoxin 5 receptors were performed to corroborate the in vitro results, which revealed good binding profiles on the examined protein targets. A standard atomistic 100 ns dynamic simulation investigation was used to further evaluate the interaction stability of the promising phytocompounds, and the results showed conformational stability in the binding cavity. The obtained results highlighted the medicinal use of D. flabellifolia as source of bioactive compounds, as antioxidant, antibacterial, and antifungal agent

    The prognostic value of four interleukin-1 gene polymorphisms in caucasian women with breast cancer – a multicenter study

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    <p>Abstract</p> <p>Background</p> <p>The proinflammatory cytokine interleukin-1 (IL-1) is known to play an important role in the carcinogenesis of breast cancer. Although IL-1 gene polymorphisms were reported to be associated with increased risk of breast cancer, their influence on survival of Caucasian breast cancer patients remains to be shown.</p> <p>Methods</p> <p>We studied the influence of four common gene polymorphisms (<it>IL1A </it>-889C/T, <it>IL1B </it>-511C/T, <it>IL1B </it>+3953E1/E2, and <it>IL1RN </it>long/2) of the IL-1 family on survival in 262 Caucasian patients with breast cancer by univariate and multivariate survival analysis. The combined effect of the four gene polymorphisms on overall survival was studied by haplotype analysis.</p> <p>Results</p> <p>In the present study 38 cases of cancer related death and a median time of follow-up (range) of 55.3 (0.4–175.8) months was observed. <it>IL1RN </it>2/2 (homozygous mutant) gene polymorphism was associated with shortened disease free and overall survival in a univariate (p = 0.001 and p = 0.01, respectively) and multivariate analysis (p = 0.002, Odds Ratio [95% Confidence Interval] = 3.6 [1.6–8.0] and p = 0.05, Odds Ratio = 3.0 [1.1–9.3], respectively). Presence of the homozygous mutant genotype of the <it>IL1A </it>-889 and <it>IL1B </it>+3953 gene polymorphism was associated with overall survival in the univariate (p = 0.004 and p = 0.002, respectively), but not in the multivariate analysis. No association was observed between all possible haplotype combinations and overall survival.</p> <p>Conclusion</p> <p>Carriage of the mutant alleles of <it>IL1RN </it>was independently associated with shortened disease free and overall survival rates in Caucasian patients with breast cancer.</p
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