35 research outputs found

    Upper critical field from normal state fluctuations in Bi2_2Sr2_2CuO6+δ_{6+\delta}

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    The in-plane magnetoresistance of an epitaxial Bi2_2Sr2_2CuO6+δ_{6+\delta} thin film was systematically investigated as a function of doping, above TcT_c. The orbital magnetoconductance is used to extract the crossover field line Hc2(T)H_{c2}^*(T) in the fluctuation regime. This field is found in good agreement with the upper critical field obtained from resistivity data below TcT_c, and exhibits a similar upward curvature, thus pointing toward the existence of a critical correlation length. The consequences regarding the nature of the resistive transition are discussed

    Neurosurgical management of anterior meningo-encephaloceles about 60 cases

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    Anterior meningo-encephaloceles (AME) are congenital malformations characterized by herniation of brain tissue and meninges through a defect in the cranium, in frontal, orbital, nasal and ethmoidal regions. The management of this complex congenital malformation is controversial according to whether use, an intracranial, extra-cranial or combined approach. This is the first largest series published in Africa, in which we present our experience in the operative management of AME; we share our recommendation in technical consideration for surgical approach with review of the literature. All patients beneficed of neuro-radiological investigations including Plan X rays, Spiral Three dimensional CT scan and MRI. Ophthalmologic and maxillo-facial evaluations were done in all the cases. MEA are surgically approached in various ways, mainly on the basis of its location and type, by cranio-facial approach in one-step, or in two stages by intracranial approach followed by facial approach, only by cranial approach or facial approach. The surgical results were evaluated in the follow up on the basis of disappearance of cranio-facial tumefaction with correction of hypertelorism. 60 children with AME were treated in our department between January 1992 and December 2012. The mean age at time of surgery was 14 months (20 days to 18 years) with slight men predominance (28 females/32 males). Cranio-facial team operated 21 patients, 16 were operated in two stages by intracranial approach followed by facial approach, 20 cases beneficed the neurosurgical approach and three only the facial approach Some post operative complications were observed: 2 cases of post operative hydrocephalus underwent shunt; CSF fistulas in three cases cured by spinal drainage, one death due to per operative hypothermia, 3 cases of recurrence how needed second surgery. After mean follow up for 80 months (1 year to 19 years) theses techniques permitted a good cosmetics results in 42 cases, average cosmetics results in 8 cases, poor results in 5 cases and worse cosmetics results in 4 cases, The AME are rare conditions we used the multiples approach first intracranial approach followed by facial approach, but after 1998 we used one-step correction by combined approach, only cranial approach when needed or facial correction

    Equilibrium and Kenitic Modeling of Cd(II) Adsorption from Aqueous Solution using Tricalcium Phosphate

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    The performance of adsorption of Cd(II) from aqueous solutions onto tricalcium phosphate Ca3(PO4)2 (TCP) have been determined and studied with kinetic and isotherm models. The effect of contact time, concentration of Cd(II) was studied. Extraction kinetics is very fast, Indeed t=5 mn. The amount of TCP sorbed per gram of Cd(II) qt (mg/g) increased with increasing initial Cd(II) concentration. The adsorption of Cd(II) by TCP followed pseudo-second order kinetics. Diffusion intraparticle is the only rate-controlling step. Adsorption equilibrium data were analyzed by Langmuir, Frendlich and Temkin isotherm equation using regression analysis. Langmuir found to best represent the data for Cd(II) adsorption onto TCP. The negative value of change in Gibbs free energy (?G°=-4.249 Kj/mol) indicates the feasible and spontaneous adsorption. The positive value of the variation of adsorption energy ?Q=31.48 Kj/mol indicate that the adsorption reaction is exothermic. Keywords: Cd(II) adsorption, Isotherm, Kenitic, Tricalcium phosphat

    New Mediterranean Marine biodiversity records (June 2013)

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    This paper concerns records of species that have extended their distribution in the Mediterranean Sea. The finding of the rare brackish angiosperm Althenia filiformis in the island of Cyprus is interesting since its insertion in the Red Data Book of the Flora of Cyprus is suggested. The following species enriched the flora or fauna lists of the relevant countries: the red alga Sebdenia dichotoma (Greece), the hydrachnid mite Pontarachna adriatica (Slovenia), and the thalassinid Gebiacantha talismani (Turkey). Several alien species were recorded in new Mediterranean localities. The record of the burrowing goby Trypauchen vagina in the North Levantine Sea (Turkish coast), suggests the start of spreading of this Lessepsian immigrant in the Mediterranean Sea. The findings of the following species indicate the extension of their occurrence in the Mediterranean Sea: the foraminifer Amphistegina lobifera (island of Zakynthos, Greece), the medusa Cassiopea andromeda (Syria), the copepod Centropages furcatus (Aegean Sea), the decapod shrimp Melicertus hathor (island of Kastellorizo, Greece), the crab Menoethius monoceros (Gulf of Tunis), the barnacles Balanus trigonus, Megabalanus tintinnabulum, Megabalanus coccopoma and the bivalves Chama asperella, Cucurbitula cymbium (Saronikos Gulf, Greece)

    Kinetic studies of adsorption of Cu (II) from aqueous solution by coriander seeds (Coriandrum Sativum)

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    The adsorption of copper ions Cu2+ by Coriandrum Sativum seeds (CSS) from aqueous solution was studied in order to highlight the importance of coriander seeds as a potential tool in the treatment of wastewaters containing heavy metals. The kinetic studies of adsorption of Cu (II) were discussed using the spectroscopic technique “Inducting Coupled Plasma” (ICP). The effects of initial copper ion concentration and contact time were determined. All results show that coriander seeds have, over their culinary and medicinal benefits, a significant adsorbent power of copper ions

    Kinetic studies of adsorption of Cu (II) from aqueous solution by coriander seeds (Coriandrum Sativum)

    No full text
    The adsorption of copper ions Cu2+ by Coriandrum Sativum seeds (CSS) from aqueous solution was studied in order to highlight the importance of coriander seeds as a potential tool in the treatment of wastewaters containing heavy metals. The kinetic studies of adsorption of Cu (II) were discussed using the spectroscopic technique “Inducting Coupled Plasma” (ICP). The effects of initial copper ion concentration and contact time were determined. All results show that coriander seeds have, over their culinary and medicinal benefits, a significant adsorbent power of copper ions

    Adsorption of Cr (III) from aqueous solution by two forms of a superabsorbant polymer : parametric study and effect of activation mode

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    The adsorption of chromium ions Cr3+ using two forms of a superabsorbant polymer PANa from aqueous solution was investigated. On one hand the equilibrium pH with the distilled water and the pH of point of zero charge have been studied in order to characterize the acid-base behavior of both of PANa forms. On the other hand, the effect of contact time between PANa and the metallic solution and stirring speed of aqueous solution on the adsorption rate were established to highlight the importance of PANa as an efficient adsorbent of chromium ions Cr3+

    Adsorption of Cr (III) from aqueous solution by two forms of a superabsorbant polymer : parametric study and effect of activation mode

    No full text
    The adsorption of chromium ions Cr3+ using two forms of a superabsorbant polymer PANa from aqueous solution was investigated. On one hand the equilibrium pH with the distilled water and the pH of point of zero charge have been studied in order to characterize the acid-base behavior of both of PANa forms. On the other hand, the effect of contact time between PANa and the metallic solution and stirring speed of aqueous solution on the adsorption rate were established to highlight the importance of PANa as an efficient adsorbent of chromium ions Cr3+
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