281 research outputs found

    The influence of doping with Ca and Mg in YBa2Cu3O7-ÎŽ ceramic

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    We have investigated the effect of partial substitution of Ca for Y and/or Mg for Cu on structural, compositional and magnetic properties in ÎłBa 2 Cu 3 O 7-ÎŽ polycrystalline compounds. All prepared samples were found to be single phase with small fraction of Ba-secondary phases. Substitution by more than 2% of magnesium causes an increase of spurious phases. Energy Dispersive Spectroscopy (EDS) revealed that the distribution of Ca in the sample is quite homogenous. DC susceptibility measurements show that superconducting transition temperature Tc is reduced much more by Ca than Mg. Hysteresis loops reveal that magnetic irreversibility is decreased by Ca and Mg content. The deduced critical current density Jc does not follow the same variation. Ca alone reduces Jc for x=0.1 and x=0.2. Together with Ca, Mg compensates the reduction of Jc and increasing its content near the solubility limit gives higher Jc than in the undoped sample

    Visualization of Distributed Algorithms Based on Graph Relabelling Systems1 1This work has been supported by the European TMR research network GETGRATS, and by the “Conseil RĂ©gional d' Aquitane”.

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    AbstractIn this paper, we present a uniform approach to simulate and visualize distributed algorithms encoded by graph relabelling systems. In particular, we use the distributed applications of local relabelling rules to automatically display the execution of the whole distributed algorithm. We have developed a Java prototype tool for implementing and visualizing distributed algorithms. We illustrate the different aspects of our framework using various distributed algorithms including election and spanning trees

    Influence of 1-Methylcyclopropene Treatment on Postharvest Quality of Four Scab (Venturia inaequalis)-Resistant Apple Cultivars

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    Scab (Venturia inaequalis) is a very serious disease for apples causing up to 80% of loss in yield but there are only a few studies on postharvest quality of scab-resistant cultivars. In this study we evaluated the effect of 1-methylcyclopropene (1-MCP) on fruit quality, total phenolic content, and antioxidant capacity after storage of four scab-resistant cultivars and compared to a standard cultivar, “Golden Delicious.” In general, ethylene production and respiration rates significantly differed among cultivars, between control and 1-MCP-treated fruits, and between storage duration regimes. 1-MCP treatment retarded fruit softening and lowered juice pH but storage effect on soluble solids and acidity depended on cultivar and 1-MCP treatment. Total phenolic content was significantly affected by storage duration and 1-MCP treatment. Antioxidant capacity of the four scab-resistant cultivars was either similar to or significantly higher than that of “Golden Delicious” with the 1-MCP-treated fruits having significantly higher antioxidant capacity than the nontreated fruits after storage. Our results clearly show that the quality of four scab-resistant cultivars was comparable to that of “Golden Delicious” and 1-MCP effect differed among cultivars. These differences need to be considered in developing storage regime to minimize quality deterioration during long-term storage

    Traitement de l’incontinence urinaire post-opĂ©ratoire de l’homme par bandelette sous urĂ©trale: A propos de 16 cas

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    Objectif: Evaluer les rĂ©sultats prĂ©liminaires de la mise en place d’une bandelette sous urĂ©trale pour le traitement d’incontinence urinaire suite Ă  une chirurgie prostatique chez l’homme selon la technique de Comiter modifiĂ©e (sans vissage osseux). Patients et mĂ©thodes: Entre janvier 2005 et dĂ©cembre 2006, 16 patients ont Ă©tĂ© pris en charge pour incontinence urinaire qui apparut aprĂšs chirurgie prostatique. Une bandelette de polypropylĂšne fixĂ©e sur le pĂ©rioste des branches ischio-pubiennes par des fils de nylon et comprimant l’urĂštre bulbaire a Ă©tĂ© mise en place. L’évaluation prĂ© et post-opĂ©ratoire a Ă©tĂ© basĂ©e sur l’examen clinique et le nombre de protections utilisĂ©es par jour. Les patients ont Ă©tĂ© revus Ă  un mois post-opĂ©ratoire, puis tous les trois mois. RĂ©sultats: Avec un recul moyen de 18 mois, 11 patients sont continents ne nĂ©cessitant pas deprotection et 3 patients sont nettement amĂ©liorĂ©s. Un Ă©chec a Ă©tĂ© notĂ© chez un patient qui avait prĂ©sentĂ© initialement une incontinence sĂ©vĂšre. Un autre patient a dĂ©veloppĂ© une infection de la bandelette nĂ©cessitant son retrait et a Ă©tĂ© exclus de la sĂ©rie pour l’évaluation fonctionnelle. Nousn’avons pas constatĂ© de douleurs pĂ©rinĂ©ales persistantes ni d’érosion urĂ©trale ni d’ostĂ©ite. Conclusion: Notre modification de la technique selon Comiter semble avoir des rĂ©sultats satisfaisants comparables avec la technique originale. Elle prĂ©sente un avantage Ă©conomique certain par rapport Ă  d’autres kits du marchĂ©

    Effect of Al substitution on structural and electrical properties of Bi1.6Pb0.4Sr2CaCu2-x Mx O8+ÎŽ superconducting ceramics

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    In this work we study the effect on structural and electrical properties of superconducting compound Bi1.6Pb0.4Sr 2CaCu2-y My O8+Ύ were M=Al (with y=0-0.6). The samples were prepared by the solid-state reaction method. The samples have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), direct current (DC) resistivity versus temperature ρ(T) and alternative current (AC) susceptibility measurements. Structural analysis shows that the crystalline lattice structure of the prepared sample belongs, mainly, to the superconductive tetragonal phase Bi(Pb)2212. The SEM micrographs show that in the undoped sample the grain size has a random distribution with few grains greater than 5 Όm. The grains are very dense and well connected. A quite different microstructure is obtained for the doped samples of which grains are more connected with a flat characteristic shape of Bi(Pb)2212 superconductors. All samples exhibit a superconducting character and Tc and the superconducting volume fraction decrease with increasing rate of aluminum

    IGL-1 solution reduces endoplasmic reticulum stress and apoptosis in rat liver transplantation

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    Injury due to cold ischemia reperfusion (I/R) is a major cause of primary graft non-function following liver transplantation. We postulated that I/R-induced cellular damage during liver transplantation might affect the secretory pathway, particularly at the endoplasmic reticulum (ER). We examined the involvement of ER stress in organ preservation, and compared cold storage in University of Wisconsin (UW) solution and in Institute Georges Lopez-1 (IGL-1) solution. In one group of rats, livers were preserved in UW solution for 8 h at 4 °C, and then orthotopic liver transplantation was performed according to Kamada's cuff technique. In another group, livers were preserved in IGL-1 solution. The effect of each preservation solution on the induction of ER stress, hepatic injury, mitochondrial damage and cell death was evaluated. As expected, we found increased ER stress after liver transplantation. IGL-1 solution significantly attenuated ER damage by reducing the activation of three pathways of unfolded protein response and their effector molecules caspase-12, C/EBP homologous protein-10, X-box-binding protein 1, tumor necrosis factor-associated factor 2 and eukaryotic translation initiation factor 2. This attenuation of ER stress was associated with a reduction in hepatic injury and cell death. Our results show that IGL-1 solution may be a useful means to circumvent excessive ER stress reactions associated with liver transplantation, and may optimize graft quality

    Influence of 1-Methylcyclopropene Treatment on Postharvest Quality of Four Scab ( Venturia inaequalis

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    Scab (Venturia inaequalis) is a very serious disease for apples causing up to 80% of loss in yield but there are only a few studies on postharvest quality of scab-resistant cultivars. In this study we evaluated the effect of 1-methylcyclopropene (1-MCP) on fruit quality, total phenolic content, and antioxidant capacity after storage of four scab-resistant cultivars and compared to a standard cultivar, “Golden Delicious.” In general, ethylene production and respiration rates significantly differed among cultivars, between control and 1-MCP-treated fruits, and between storage duration regimes. 1-MCP treatment retarded fruit softening and lowered juice pH but storage effect on soluble solids and acidity depended on cultivar and 1-MCP treatment. Total phenolic content was significantly affected by storage duration and 1-MCP treatment. Antioxidant capacity of the four scab-resistant cultivars was either similar to or significantly higher than that of “Golden Delicious” with the 1-MCP-treated fruits having significantly higher antioxidant capacity than the nontreated fruits after storage. Our results clearly show that the quality of four scab-resistant cultivars was comparable to that of “Golden Delicious” and 1-MCP effect differed among cultivars. These differences need to be considered in developing storage regime to minimize quality deterioration during long-term storage

    Endoplasmic reticulum stress inhibition protects steatotic and non-steatotic livers in partial hepatectomy under ischemia–reperfusion

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    During partial hepatectomy, ischemia–reperfusion (I/R) is commonly applied in clinical practice to reduce blood flow. Steatotic livers show impaired regenerative response and reduced tolerance to hepatic injury. We examined the effects of tauroursodeoxycholic acid (TUDCA) and 4-phenyl butyric acid (PBA) in steatotic and non-steatotic livers during partial hepatectomy under I/R (PH+I/R). Their effects on the induction of unfolded protein response (UPR) and endoplasmic reticulum (ER) stress were also evaluated. We report that PBA, and especially TUDCA, reduced inflammation, apoptosis and necrosis, and improved liver regeneration in both liver types. Both compounds, especially TUDCA, protected both liver types against ER damage, as they reduced the activation of two of the three pathways of UPR (namely inositol-requiring enzyme and PKR-like ER kinase) and their target molecules caspase 12, c-Jun N-terminal kinase and C/EBP homologous protein-10. Only TUDCA, possibly mediated by extracellular signal-regulated kinase upregulation, inactivated glycogen synthase kinase-3ÎČ. This is turn, inactivated mitochondrial voltage-dependent anion channel, reduced cytochrome c release from the mitochondria and caspase 9 activation and protected both liver types against mitochondrial damage. These findings indicate that chemical chaperones, especially TUDCA, could protect steatotic and non-steatotic livers against injury and regeneration failure after PH+I/R
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