22 research outputs found

    New aspects of the interaction of the antibiotic coralyne with RNA: coralyne induces triple helix formation in poly(rA)•poly(rU)

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    The interaction of coralyne with poly(A)•poly(U), poly(A)•2poly(U), poly(A) and poly(A)•poly(A) is analysed using spectrophotometric, spectrofluorometric, circular dichroism (CD), viscometric, stopped-flow and temperature-jump techniques. It is shown for the first time that coralyne induces disproportionation of poly(A)•poly(U) to triplex poly(A)•2poly(U) and single-stranded poly(A) under suitable values of the [dye]/[polymer] ratio (CD/CP). Kinetic, CD and spectrofluorometric experiments reveal that this process requires that coralyne (D) binds to duplex. The resulting complex (AUD) reacts with free duplex giving triplex (UAUD) and free poly(A); moreover, ligand exchange between duplex and triplex occurs. A reaction mechanism is proposed and the reaction parameters are evaluated. For CD/CP> 0.8 poly(A)•poly(U) does not disproportionate at 25°C and dye intercalation into AU to give AUD is the only observed process. Melting experiments as well show that coralyne induces the duplex disproportionation. Effects of temperature, ionic strength and ethanol content are investigated. One concludes that triplex formation requires coralyne be only partially intercalated into AUD. Under suitable concentration conditions, this feature favours the interaction of free AU with AUD to give the AUDAU intermediate which evolves into triplex UAUD and single-stranded poly(A). Duplex poly(A)•poly(A) undergoes aggregation as well, but only at much higher polymer concentrations compared to poly(A)•poly(U)

    Recommandations aux voyageurs aériens (enquête auprès de 71 médecins généralistes de Haute-Garonne)

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    L augmentation du trafic aérien et le vieillissement de la population confrontent les médecins généralistes à des demandes croissantes de conseils avant de prendre l avion. Le but de ce travail est d évaluer la pratique en matière de recommandations aux voyageurs aériens à l aide d un questionnaire adressé à 100 médecins généralistes de Haute-Garonne sélectionnés de façon aléatoire. Le taux élevé de répondants (71%) signe l intérêt porté au sujet. 97% d entre eux ont donné des conseils (surtout sur l insuffisance veineuse et la prévention de la thrombophlébite) et 56% contre-indiqué un voyage aérien. Pourtant, seuls 8% ont cité leur source d information, la pratique n est pas souvent cohérente avec les recommandations internationales disponibles. Une évaluation clinique soigneuse est la clé de la prévention pour sélectionner les voyageurs à risque pour l avion. Une fiche de conseils pourrait être remise aux passagers à la réservation et une formation spécifique dispensée aux médecins.TOULOUSE3-BU Santé-Centrale (315552105) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

    Structural and chemical characterization of hardwood from tree species with applications as Bioenergy Feedstocks

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    Eucalypt species are a group of flowering trees widely used in pulp production for paper manufacture. For several decades, the wood pulp industry has focused research and development efforts on improving yields, growth rates and pulp quality through breeding and the genetic improvement of key tree species. Recently, this focus has shifted from the production of high quality pulps to the investigation of the use of eucalypts as feedstocks for biofuel production. Here the structure and chemical composition of the heartwood and sapwood of Eucalyptus dunnii, E. globulus, E. pillularis, E. urophylla, an E. urophylla-E. grandis cross, Corymbia citriodora ssp. variegata, and Acacia mangium were compared using nuclear magnetic resonance spectroscopy (NMR), X-ray diffraction (XRD) and biochemical composition analysis. Some trends relating to these compositions were also identified by Fourier transform near infrared (FT-NIR) spectroscopy. These results will serve as a foundation for a more comprehensive database of wood properties that will help develop criteria for the selection of tree species for use as biorefinery feedstocks

    Decomposition behaviors of various crystalline celluloses as treated by semi-flow hot-compressed water

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    Various types of crystalline cellulose consisting of group I (cell I, IIII, IVI) and group II (cell II, IIIII, IVII) prepared from cotton linter were adjusted for their degree of polymerization (DP) as starting materials. These celluloses were then treated by semi-flow hot-compressed water (HCW) at 230–270 °C/10 MPa/2–15 min to study their decomposition behaviors. The treatments performed resulted in residues of celluloses and water-soluble (WS) portions. Consequently, the crystallinity of the residues was found to remain the same, but the DP was reduced as the temperature increased. Additionally, X-ray diffractometry and Fourier transform-infrared analyses demonstrated that crystallographic changes occurred for residues of cell IIII, IVI and IIIII. Despite these changes, the overall results of the residues showed that group I has higher resistance to decomposing than group II. As for the WS portions, the yields of the hydrolyzed and degraded products were higher in group II than group I, indicating that group II is less resistant to decomposition by HCW treatment. Results for both the residues and WS portions are in agreement with each other, showing that the degree of difficulty of decomposition was higher in group I than group II. Therefore, the decomposition behaviors of the celluloses are due to differences in the crystalline forms

    The prevalence of mixed genotype infections in Turkish patients with hepatitis c: a multicentered assessment

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    AKTAS, OSMAN/0000-0002-7762-4108; Karsligil, Tekin/0000-0001-7672-3625; cekin, yesim/0000-0003-4393-5618; Sayiner, Ayca/0000-0001-6750-2353; Altindis, Mustafa/0000-0003-0411-9669WOS: 000463988900008PubMed: 30969089Background: HCV virus infections are one of the major health problems in the world that can cause cirrhosis and liver cancer at a higher rate than other hepatitis data. The aim of this study was to determine the prevalence of mixed infections with different HCV genotypes in Turkey and also to evaluate the current HCV genot pe and subtype distributions by a multicentered assessment. Methods: The HCV genotype data of 17,578 hepatitis C patients collected from 23 centers from different geographic regions covering all Turkey were collected. The data included information about the HCV genotypes in the last 10 years (bail een 2007 and 2016), demographic properties of the patients and the methods/systems used to determine the genotypes. Results: Two hundred twenty-eight of the patients (1.3%) had mixed genotype. The most common mixed genotype combination was 1b + 4 (0.83%) followed by 1a + 1b (0.26%). Genotype distribution varies according to geographical regions. However, genotype 1 (82.92%) was the most common genotype in all regions and all years. This was followed by genotype 3 (7.07%) and genotype 4 (5.43%). A variety of methods were used by the centers including sequencing, pyrosequencing, real-time PCR, in-house RFLP, reverse hybridization (LIPA), and hybridization. Conclusions: Infection with mixed HCV genotypes in Turkey is uncommon. Genotype distribution varies according to geographic regions; the most common genotype 1 is encountered all oN er the country, while genotypes 3 and 4 are only in some of the centers. Since there is limited information about mixed HCV infection, further investigations are needed to determine the clinical importance of mixed HCV infection
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