409 research outputs found

    Les programmes internationaux de recherche sur la forêt méditerranéenne.

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    Débute par un historique en matière de coopération et de coordination (Silva Mediterranea), puis fait le point sur la recherche actuelle à travers les données des principales organisations internationales concernées : F.A.O., U.N.E.S.C.O., I.U.F.R.O., C.E.E., C.I.H.E.A.M

    Sustainable Triazine-Based Dehydro-Condensation Agents for Amide Synthesis

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    Conventional methods employed today for the synthesis of amides often lack of economic and environmental sustainability. Triazine-derived quaternary ammonium salts, e.g., 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM(Cl)), emerged as promising dehydro-condensation agents for amide synthesis, although suffering of limited stability and high costs. In the present work, a simple protocol for the synthesis of amides mediated by 2-chloro-4,6-dimethoxy-1,3,5-triazine (CDMT) and a tert-amine has been described and data are compared to DMTMM(Cl) and other CDMT-derived quaternary ammonium salts (DMT-Ams(X), X: Cl- or ClO4-). Different tert-amines (Ams) were tested for the synthesis of various DMT-Ams(Cl), but only DMTMM(Cl) could be isolated and employed for dehydro-condensation reactions, while all CDMT/tert-amine systems tested were efficient as dehydro-condensation agents. Interestingly, in best reaction conditions, CDMT and 1,4-dimethylpiperazine gave N-phenethyl benzamide in 93% yield in 15 min, with up to half the amount of tert-amine consumption. The efficiency of CDMT/tert-amine was further compared to more stable triazine quaternary ammonium salts having a perchlorate counter anion (DMT-Ams(ClO4)). Overall CDMT/tert-amine systems appear to be a viable and more economical alternative to most dehydro-condensation agents employed today

    Anti-oxidant potential and gap junction-mediated intercellular communication as early biological markers of mercuric chloride toxicity in MDCK cell line.

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    In this study, the early nephrotoxic potential of mercuric chloride (HgCl(2)) has been evaluated in vitro, by exposing a renal-derived cell system, the tubular epithelial Madin-Darby canine kidney (MDCK) cell line, to the presence of increasing HgCl(2) concentrations (0.1-100 microM) for different periods of time (from 4 to 72 h). As possible biological markers of the tubular-specific toxicity of HgCl(2) in exposed-MDCK cultures we analysed: (i) critical biochemical parameters related to oxidative stress conditions and (ii) gap-junctional function (GJIC). HgCl(2) cytotoxicity was evaluated by cell-density assay. The biochemical analysis of the pro-oxidant properties of the mercuric ion (Hg(2+)) was performed by evaluating the effect of the metal salt on the antioxidant status of the MDCK cells. The cell glutathione (GSH) content and the activity of glutathione peroxidase (Gpx) and catalase (Cat), two enzymes engaged in the H(2)O(2) degradation, were quantified. HgCl(2) influence on MDCK GJIC was analysed by the microinjection/dye-transfer assay. HgCl(2)-induced morphological changes in MDCK cells were also taken into account. Our results, proving that subcytotoxic (0.1-10 microM) HgCl(2) concentrations affect either the antioxidant defences of MDCK cells or their GJIC, indicate these critical functions as suitable biological targets of early mercury-induced tubular cell injury

    Influence of Various Light Timber Retrofit Layouts on the Dynamic Response of Typical Duch Masonry Terraced Houses

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    A majority of the residential building stock in Groningen (The Netherlands), which has been lately exposed to low intensity ground motions due to gas extraction, consists of unreinforced masonry (URM) structures not originally designed to withstand earthquakes. Amongst them, the terraced house building typology proved to be particularly vulnerable towards horizontal actions. Experimental results from a recently performed shake-table test on a full-scale terraced house prototype, characterised by the presence of a timber retrofitting system, seem to indicate that the dynamic response of these structures might be consistently improved through the employment of such a cost-effective light retrofitting solution. In this work, an advanced discontinuum-based model, implemented in the framework of the Applied Element Method (AEM), is developed to extend experimental results and to numerically investigate the influence of a number of additional timber retrofit layouts, characterised by different geometrical configurations, on the building behaviour. Each timber component was explicitly represented in the AEM models to represent the possible interaction among URM walls and the retrofitting system. First, the proposed modelling strategy is validated against experimental tests on both non-retrofitted and retrofitted URM panels subjected to cyclic shear compression loading. Then, calibrated mechanical parameters were directly implemented in the full-scale building model. Given the good agreement between numerical and experimental outcomes in terms of both damage evolution and hysteretic response, a comprehensive parametric study was undertaken. Numerical evidence seems to suggest that the employment of different retrofit layouts may have a significant influence on the dynamic behaviour of the selected building typology

    Low drug levels and thrombotic complications in high-risk atrial fibrillation patients treated with direct oral anticoagulants

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    Essentials Direct oral anticoagulants (DOACs) do not require laboratory monitoring currently. DOAC specific measurements were performed at trough in patients with atrial fibrillation. Patients who developed thromboembolic events showed lower DOAC plasma levels. This study supports the concept of measuring DOAC levels at steady state. Summary: Background Direct oral anticoagulants (DOACs) are administered at fixed doses without the need for dose adjustment according to laboratory testing. High interindividual variability in drug blood levels has been shown with all DOACs. To evaluate a possible relationship between DOAC C-trough anticoagulant levels and thromboembolic events, 565 consecutive naive patients with atrial fibrillation (AF) were enrolled in this study performed within the START Laboratory Registry. Methods DOAC-specific measurements (diluted thrombin time or anti-activated factor II calibrated for dabigatran; anti-activated FX calibrated for rivaroxaban or apixaban) at C-trough were performed locally at steady state within 15–25 days after the start of treatment. For each DOAC, the interval of C-trough levels, from the limit of quantification to the highest value, was subdivided into four equal classes, and results were attributed to these classes; the median values of results were also calculated. Thromboembolic complications occurring during 1 year of follow-up were recorded. Results Thromboembolic events (1.8%) occurred in 10 patients who had baseline C-trough levels in the lowest class of drug levels. The incidence of thromboembolic events among patients with DOAC C-trough levels in the lowest level class was 2.4%, and that in the remaining groups was 0%. The patients with thrombotic complications also had a higher mean CHA2DS2-VASc score than that of the total patient population: 5.3 (95% confidence interval [CI] 4.3–6.3 versus 3.0 (95% CI 2.9–3.1). Conclusion In this study cohort, thrombotic complications occurred only in DOAC-treated AF patients who had very low C-trough levels, with a relatively high CHA2DS2-VASc score. Larger studies are warranted to confirm these preliminary observations. © 2018 The Authors. Journal of Thrombosis and Haemostasis published by Wiley Periodicals, Inc. on behalf of International Society on Thrombosis and Haemostasis

    Reduction of precocious peri-implant resorption cone

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    Aim: After implant-insertion, bone tissue, newly-formed on peri-implant crest, undergoes to a mild marginal osseous readjustment due to build-up of inflammatory cell tissue (ICT). The present study verifies the possibility to limit bone resorption by placing implant fixtures 0.5 mm outside cortical bone edge. Methods: A clinically-controlled randomized study on 100 implants has been performed to compare early resorption process of implant fixtures placed 0.5 mm outside cortical bone edge with implant-fixtures inserted according to juxtacortical bone conventional protocols. Results: After 6 months, bone implant level was higher with emersion approach (-1.01\ub10.54 mm, mean\ub1SD) than with submerged treatment (-1.56\ub10.5 mm) (P<0.001). Conclusion: Factors to achieve an excellent result at mean-long term seem to be very good, even though the latter have to be confirmed by follow-up

    The importance of molecular characters when morphological variability hinders diagnosability: systematics of the moon jellyfish genus Aurelia (Cnidaria: Scyphozoa)

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    Cryptic species have been detected across Metazoa, and while no apparent morphological features distinguish them, it should not impede taxonomists from formal descriptions. We accepted this challenge for the jellyfish genus Aurelia, which has a long and confusing taxonomic history. We demonstrate that morphological variability in Aurelia medusae overlaps across very distant geographic localities. Even though some morphological features seem responsible for most of the variation, regional geographic patterns of dissimilarities are lacking. This is further emphasized by morphological differences found when comparing lab-cultured Aurelia coerulea medusae with the diagnostic features in its recent redescription. Previous studies have also highlighted the difficulties in distinguishing Aurelia polyps and ephyrae, and their morphological plasticity. Therefore, mostly based on genetic data, we recognize 28 species of Aurelia, of which seven were already described, 10 are formally described herein, four are resurrected and seven remain undescribed. We present diagnostic genetic characters for all species and designate type materials for newly described and some resurrected species. Recognizing moon jellyfish diversity with formal names is vital for conservation efforts and other studies. This work clarifies the practical implications of molecular genetic data as diagnostic characters, and sheds light on the patterns and processes that generate crypsis.Fil: Lawley, Jonathan W.. Universidade de Sao Paulo; Brasil. Griffith University; AustraliaFil: Gamero Mora, Edgar. Universidade de Sao Paulo; BrasilFil: Maronna, Maximiliano Manuel. Universidade de Sao Paulo; BrasilFil: Chiaverano, Luciano Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Stampar, Sérgio N.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Hopcroft, Russell R.. University of Alaska; Estados UnidosFil: Collins, Allen G.. National Museum of Natural History; Estados UnidosFil: Morandini, André C.. Universidade de Sao Paulo; Brasi

    Morphology is not always useful for diagnosis, and that’s ok: Species hypotheses should not be bound to a class of data. Reply to Brown and Gibbons (S Afr J Sci. 2022;118(9/10), Art. #12590)

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    This paper serves as a reply to the Commentary by Brown and Gibbons (S Afr J Sci. 2022;118(9/10), Art. #12590) on our recently published paper on systematics of the moon jellyfish genus Aurelia (Lawley et al. PeerJ 2021;9, e11954)). We emphasise that we are not advocating for the routine use of molecular data alone in taxonomic diagnoses, rather that it is a valid approach in cases where, after detailed analyses, morphological features are shown to be unreliable

    Archaeology and Archaeometry of a local production of Black Glazed Ware at Pompeii

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    International audienceThe paper focuses on a local production of Black Glazed ware attested in Pompeii between the mid-fourth and the early-third century B.C. The ceramics thereafter presented were found in a specific archaeological deposit termed as X B11, brought to light in stratigraphic excavations undertaken in the forum area in 1980/81 by P. Arthur on behalf of the local Superintendence
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