851 research outputs found

    Overview of the JET results in support to ITER

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    The 2014–2016 JET results are reviewed in the light of their significance for optimising the ITER research plan for the active and non-active operation. More than 60 h of plasma operation with ITER first wall materials successfully took place since its installation in 2011. New multi-machine scaling of the type I-ELM divertor energy flux density to ITER is supported by first principle modelling. ITER relevant disruption experiments and first principle modelling are reported with a set of three disruption mitigation valves mimicking the ITER setup. Insights of the L–H power threshold in Deuterium and Hydrogen are given, stressing the importance of the magnetic configurations and the recent measurements of fine-scale structures in the edge radial electric. Dimensionless scans of the core and pedestal confinement provide new information to elucidate the importance of the first wall material on the fusion performance. H-mode plasmas at ITER triangularity (H = 1 at βN ~ 1.8 and n/nGW ~ 0.6) have been sustained at 2 MA during 5 s. The ITER neutronics codes have been validated on high performance experiments. Prospects for the coming D–T campaign and 14 MeV neutron calibration strategy are reviewed.European Commission (EUROfusion 633053

    Phytochemical study and biological evaluation of the stem of Derris ferruginea Bentham

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    The genus Derris Loureiro belongs to the tribe Milletiae of the Leguminosae. It includes about fifteen species widely found in the tropical areas of Africa and Asia [1]. These plants have been traditionally used over centuries as fish poisoning, insecticide and pesticide, particularly due to their large production of rotenone [2]. Biological activities of Derris species are various: cytotoxic, antibacterial, antifungal, and antioxidant [3,4,5]. Though major secondary metabolites found in the genus are known to be flavonoids, including prenylated flavanones, and isoflavonoids such as rotenoids, very few phytochemical informations were available on D. ferruginea [6]. Different crude extracts were obtained from the stem (2kg, Soxhlet apparatus). They were fractionated using successively MPLC, LC, FCPC® (Fast Centrifugal Partition Chromatography, Kromaton Angers), Sephadex LH-20® gel and finally purified on preparative HPLC. Chemical structures of the isolated compounds were elucidated using 1H and 13C NMR spectrum as well as Mass Spectrometry. Most of these compounds were identified as prenylated flavonoids (flavanones and isoflavonoids). Biological effects of these compounds will be reported here, particularly antimicrobial, antiparasitic activities and inhibition of the formation of AGEs (Advanced Glycation End Products involved in age- and diabetes-related chronic diseases)

    From dereplication and anti-inflammatory screening of Clusiaceae and Calophyllaceae species to novel immunomodulatory coumarins from Mesua lepidota

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    Vascular endothelium plays a central role in the development of inflammatory and immune processes, which are involved in graft rejection1. Many Clusiaceae/Calophyllaceae species (pantropical plants) biosynthesize original polyphenolic compounds exhibiting antioxidant and anti-inflammatory properties2-3. Bark, leaves and occasionally fruits from thirteen Malaysian plants belonging to the genus Calophyllum, Mesua (Calophyllaceae), Garcinia (Clusiaceae) were extracted using DCM and MeOH as the solvents. Each extract was then submitted to a HPLC-PDA-MSn dereplication analysis and its anti-inflammatory potential was evaluated on Human Umbilical Vein Endothelial Cells (HUVECs). This allowed to select the bioactive fruits DCM extract of Mesua lepidota T. Anderson for an advanced phytochemical study, which led to the identification of several new coumarin derivatives. A flow cytometry study revealed that the major component of this extract, namely lepidotol A (1), significantly inhibited the VCAM-1, HLA-II and HLA-E expression of HUVECs previously activated by TNF-α or IFN-γ cytokines.   References   1.     P. T. Clesca, Int. Congr. Ser., 2002, 1237, 181-191. 2.     F. V. Cechinel, C. Meyre-Silva, and R. Niero, Chem. Biodivers., 2009, 6, 313-327. 3.     J. González-Gallego, M. V. García-Mediavilla, S. Sánchez-Campos and M. J. Tuñón, Br. J. Nutr., 2010, 104, S15-S2

    New proaporphines from the bark of Phoebe scortechinii

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    The phytochemical study of the bark of Malaysian Phoebe scortechinii (Lauraceae) has resulted in the isolation and identification of two new proaporphine alkaloids; (+)-scortechiniine A (1) and (+)-scortechiniine B (2) together with two known proaporphines; (−)-hexahydromecambrine A (3), (−)-norhexahydromecambrine A (4), and one aporphine; norboldine (5). Structural elucidations of these alkaloids were performed using spectroscopic methods especially 1D and 2D 1H and 13C NMR

    Effets anti-inflammatoire et immunomodulateur de composés polyphénoliques isolés de Clusiaceae et de Calophyllaceae

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    L’endothélium vasculaire joue un rôle central dans le développement des réponses inflammatoires et immunitaires conduisant notamment au phénomène de rejet de greffe1. Les Clusiaceae et Calophyllaceae, plantes des régions pantropicales, biosynthétisent des dérivés polyphénoliques originaux présentant des activités anti-inflammatoires intéressantes2-3. Divers polyphénols isolés de ces plantes ont été sélectionnés, afin d’évaluer in vitro leur potentiel anti-inflammatoire et immunomodulateur sur des cellules endothéliales humaines. Plusieurs coumarines et une benzophénone se sont alors révélées inhibitrices de l’expression de marqueurs de l’inflammation et de l’immunité. Parallèlement à cette étude, les extraits dichlorométhaniques (DCM) et méthanoliques d’un panel de plantes issues des genres Garcinia (Clusiaceae), Calophyllum et Mesua (Calophyllaceae), originaires de Malaisie, ont été analysés par déréplication (HPLC-PDA-MSn). Deux extraits contenant des pharmacophores d’intérêt ont ainsi été sélectionnés pour une étude phytochimique approfondie : l’extrait DCM de fruits de Mesua lepidota, duquel ont été identifiés sept phénylcoumarines originales, que nous avons baptisées lépidotols et lépidotines, et l’extrait DCM de feuille de Calophyllum tetrapterum, ce dernier riche en benzophénones polyprénylées. Références : 1.         Brick C, Atouf O, Benseffaj N, et al. Rejet de la greffe rénale : mécanisme et prévention. Nephrol Ther 2011;7:18-26. 2.         Ali M, Arfan M, Ahmad M, et al. Anti-inflammatory xanthones from the twigs of Hypericum oblongifolium Wall. Planta Med 2011;77:2013-2018. 3.         Santa-Cecilia FV, Freitas LAS, Vilela FC, et al. Antinociceptive and anti-inflammatory properties of 7-epiclusianone, a prenylated benzophenone from Garcinia brasiliensis. Eur J Pharmacol 2011;670:280-285

    fMRI visualization of transient activations in the rat olfactory bulb using short odor stimulations

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    International audienceOdor-evoked activity in the olfactory bulb displays both spatial and temporal organization. The difficulty when assessing spatio-temporal dynamics of olfactory representation is to find a method that reconciles the appropriate resolution for both dimensions. Imaging methods based on optical recordings can reach high temporal and spatial resolution but are limited to the observation of the accessible dorsal surface. Functional magnetic resonance imaging (fMRI) may be useful to overcome this limitation as it allows recording from the whole brain. In this study, we combined ultra fast imaging sequence and short stimulus duration to improve temporal resolution of odor-evoked BOLD responses. Short odor stimulations evoked high amplitude BOLD responses and patterns of activation were similar to those obtained in previous studies using longer stimulations. Moreover, short odor exposures prevented habituation processes. Analysis of the BOLD signal time course in the different areas of activation revealed that odorant response maps are not static entities but rather are temporally dynamic as reported by recent studies using optical imaging. These data demonstrated that fMRI is a non-invasive method which could represent a powerful tool to study not only the spatial dimension of odor representation but also the temporal dimension of information processing

    First 2-Hydroxy-3-Methylbut-3-Enyl Substituted Xanthones Isolated From Plants: Structure Elucidation, Synthesis and Antifungal Activity

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    Two new 2-hydroxy-3-methylbut-3-enyl substituted xanthones, ( - )-caledol 1 and ( - )-dicaledol 2 were isolated from a dichloromethane extract of the leaves of Calophyllum caledonicum (Clusiaceae). Compounds 1 and 2 are the first 2-hydroxy-3-methylbut-3-enyl substituted xanthones isolated from natural source. Their structures were elucidated by means of combined analytical methods including HRFABMS, 1D and 2D NMR spectroscopies and also confirmed by total synthesis using biomimetic ortho -prenylphenols photooxygenation ( 1 O 2 ) as a key step. The antifungal activity against Aspergillus fumigatus is reported
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