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Characterization of Extracts from the Bark of the Gabon Hazel Tree (Coula edulis baill) for Antioxidant,Antifungal and Anti-termite Products

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Journal of Renewable Materials 2021年第1期9卷 17-33页

作者： Christ Stone Arnaud Bopenga Bopenga Henri Meyo degboevi Kevin Candelier Prosper Edou Engonga Stéphane Dumarçay Marie France Thévenon Christine Gérardin Charbonnier Philippe Gérardin Universitéde lorraine Institut National de Recherche pour l’Agriculturel’Alimentation et l’EnvironnementLaboratoire d’Etudes et de Recherche sur le Matériau BoisNancyFrance Universitéde Montpellier Centre de Coopération Internationale en Recherche Agronomique pour le Développement-Research Unit BiomassWoodEnergyBioproductsMontpellierFrance Multidisciplinary laboratory of sciences of libreville Normal Superior SchoolLibrevilleGabon

Chemical composition of the bark extracts of Coula edulis was investigated to find potential antioxidant,anti-termite and antifungal compounds which can find useful applications in the fields of food,nutraceuticals,cosmetics or *** screening revealed the presence of several groups of active molecules such as alkaloids,polyphenols,flavonoids,saponins and sterols and/or terpenes in the different *** phenols,condensed tannins and flavonoids contents corroborated phytochemical *** chromatographymass spectrometry(GC-MS)analysis revealed compounds in dichloromethane extract different from those obtained with all the other *** and trans-9-octadecenoic acids,as well as stigmasterol andβ-sitosterol have been identified as the major compounds in the dichloromethane *** obtained with acetone and toluene/ethanol mixture(2/1,v/v)indicated the presence of few amounts of fatty acids and sugars,catechin in small amount and huge amounts of phenolic acids like gallic and ellagic *** radical 2,2-diphenyl-1-picrylhydrazyle(DPPH)and the cationic radical 2,2’-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS+)were used for evaluation of antioxidant properties of the different *** dichloromethane extracts had a very low antioxidant activity,while acetone and toluene/ethanol extracts presented EC50 values similar to those of catechin and BHT used as reference antioxidant *** of the different extracts of the bark of *** on fungal growth inhibition indicated better inhibition of the mycelium growth of brown rot fungi compared to white rot *** anti-termite activities were recorded with the aqueous extracts,while stronger activities were recorded with dichloromethane,acetone and toluene/ethanol extracts.

关键词： Antifungal antioxidant anti-termite Coula edulis baill extracts valorisation

Spectroscopic and molecular structure characterization of the bis(2-aminophenol)(5, 10, 15, 20-tetraphenylporphyrinato) cobalt(II) complex

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Open Journal of Inorganic Chemistry 2012年第4期2卷 81-87页

作者： Yassin Belghith Anissa Mansour Jean-Claude Daran Habib Nasri laboratoire de Chimie de Coordination CNRS UPR 8241 205 Route de Norbonne France laboratoire de Physico-chimie des Matériaux Faculté des Sciences de Monastir Université de Monastir Avenue de l’environn- ement Tunisia laboratoire de Physico-chimie des Matériaux Faculté des Sciences de Monastir Université de Monastir Avenue de l’environnement Tunisia

The reaction of the cobalt(II) meso-tetraphenylporphyrin (TPP) starting material with an excess of 2-aminophenol (Hon) in organic solvents, yields the cobalt(II) porphyrin species [CoII(TPP)(Hon)2] (1). This compound has been characterized by UV-vis., IR, MSI MS and 1H NMR spectroscopy. The UV-vis data and especially the proton NMR results, for the isolated product, indicated that complex 1 is a Co(II) mesoporphyrin *** X-ray molecular structure of the title compound bis(2-aminophenol) (tetraphenylporphyrinato) cobalt(II) has been determined. This structure is the first one reported of a metalloporphyrin with a 2-aminophenol axial ligand species. The central metal is hexacoordinated by the four nitrogen atoms of the pyrrole rings and the nitrogen atoms of the two Hon trans axial ligands.

关键词： Meso-Tetraphenylporphyrin Cobalt(II) 2-Aminophenol Cobalt(II) Complex X-Ray Molecular Structure

Role of the rhizosphere of a flooding-tolerant herb in promoting mercury methylation in water-level fluctuation zones

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Journal of Environmental sciences 2022年第9期34卷 139-151页

作者： Juan Wang Yuping Xiang Xiaosong Tian Cheng Zhang Guiqing Gong Jinping Xue Tao Jiang Dingyong Wang Yongmin Wang Interdisciplinary Research Center for Agriculture Green development in Yangtze River Basin College of Resources and EnvironmentSouthwest UniversityChongqing 400715China laboratory of Environmental Nanotechnology&Health Effect Chinese Academy of SciencesResearch Center for Eco-Environmental SciencesBeijing 100085China College of Resources and Safety Chongqing Vocational Institute of EngineeringChongqing 402260China Institut des sciences Analytiques et des Physico-Chimie pour l’environnement et les Materiaux(IPREM) UMR 5254CNRSUniversitede Pau et des Pays de l’AdourPau 64000France

The water-level fluctuation zone(WlFZ) has been considered as a hotspot for mercury(Hg) methylation. Flooding-tolerant herbs are gradually acclimated to this water-land ecotone, tending to form substantial root systems for improving erosion resistance. Accompanying rhizosphere microzone plays crucial but unclear roles in methylmercury(Me Hg) formation in the WlFZ. Thus, we conducted this study in the WlFZ of the Three Gorges Reservoir, to explore effects of the rhizosphere of a dominant flooding-tolerant herb(bermudagrass) on Me Hg production. The elevated Hg and Me Hg in rhizosphere soils suggest that the rhizosphere environment provides favorable conditions for Hg accumulation and methylation. The increased bioavailable Hg and microbial activity in the rhizosphere probably serve as important factors driving Me Hg formation in the presence of bermudagrass. Simultaneously, the rhizosphere environments changed the richness, diversity, and distribution of hgc A-containing microorganisms. Here, a typical ironreducing bacterium( Geobacteraceae) has been screened, however, the majority of hgc A genes detected in rhizosphere, near-, and non-rhizosphere soils of the WlFZ were unclassified. Collectively, these results provide new insights into the elevated Me Hg production as related to microbial processes in the rhizosphere of perennial herbs in the WlFZ, with general implications for Hg cycling in other ecosystems with water-level fluctuations.

关键词： Three Gorges Reservoir Water-level fluctuation zone Rhizosphere soil Methylmercury Mercury methylator

Chemically modified carbon-based electrodes for the determination of paracetamol in drugs and biological samples

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Journal of Pharmaceutical Analysis 2021年第2期11卷 138-154页

作者： Wafaa Boumya Nawal Taoufik Mounia Achak Noureddine Barka Sultan Moulay Slimane University of Beni Mellal Research Group in Environmental Sciences and Applied Materials(SEMA)FP KhouribgaB.P.14525000KhouribgaMorocco Chouaib Doukkali University Ecole Nationale des Sciences AppliqueesLaboratoire des Sciences de l’Ingenieur pour l’EnergieEl JadidaMorocco Chemical&Biochemical sciences Green Process EngineeringCBSMohammed VI Polytechnic UniversityBen GuerirMorocco

Paracetamol is a non-steroidal, anti-inflammatory drug widely used in pharmaceutical applications for its sturdy, antipyretic and analgesic action. However, an overdose of paracetamol can cause fulminant hepatic necrosis and other toxic effects. Thus, the development of advantageous analytical tools to detect and determine paracetamol is required. Due to simplicity, higher sensitivity and selectivity as well as costefficiency, electrochemical sensors were fully investigated in last decades. This review describes the advancements made in the development of electrochemical sensors for the paracetamol detection and quantification in pharmaceutical and biological samples. The progress made in electrochemical sensors for the selective detection of paracetamol in the last 10 years was examined, with a special focus on highly innovative features introduced by nanotechnology. As the literature is rather extensive, we tried to simplify this work by summarizing and grouping electrochemical sensors according to the by which manner their substrates were chemically modified and the analytical performances obtained.

关键词： Paracetamol Electrochemical sensors Modified electrodes Pharmaceutical samples

Variation of Stable Isotopes in Surface Snow along a Traverse from Coast to Plateau's interior in East Antarctica and Its Climatic Significance

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Research in Cold and Arid Regions 2009年第1期1卷 14-24页

作者： Jean Jouzel Michel Stievenard Institut Pierre Simon laplace/laboratoire des sciences du Climat et de l'environnement CEA-CNRS-University Versailles-Saint Quentin

The variations of stable water isotopes of surface snow in east Antarctic Ice Sheet, are discussed by a total of 251 samples, which were taken along a 330 km traverse from Zhongshan Station to the outer edge of the Antarctic plateau and from four snow pits excavated along the route. Analyzing results of the samples showed the expected linear relationship between the parameters ?D and ?18O with slope S1 and intercept d1. When the data set was examined using a sliding window with a width of 5 samples, it was found that there were two areas with different ratios of S1 and d1. The boundary between these two areas occurred at an elevation of about 2,000 m, suggesting two different sources of water vapour. Nearly half (47%) of the fresh-snow samples had negative deuterium excess (d=?D? 8?18O) values, but few of the snow pit samples did, suggesting that variations of ? are quickly smoothed by isotopic diffusion in the near-surface firn. Analysis of the phase relationship between ?D and deuterium excess in the snow pit stratigraphies showed that they were mostly in phase from Jan. 1994 to Sept. 1995, but mostly out of phase from Sept. 1995 to Jan. 1997.

关键词： east Antarctica ice sheet stable isotopes snow

Kinetic and product studies of the reactions of NO3 with a series of unsaturated organic compounds

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Journal of Environmental sciences 2020年第9期32卷 111-120页

作者： Yangang Ren Max McGillen Ibrahim Ouchen Veronique Daële Abdelwahid Mellouki Centre National de la Recherche Scientifique(CNRS)(UPR 3021) Observatoire des Sciences de l’Univers en région Centre(OSUC)Institut de CombustionAérothermiqueRéactivitéet Environnement(ICARE)Orléans 45071France Earth sciences department Scientific InstituteMohammed V UniversityRabat 10106Morocco le Studium loire Valley Institute for Advanced Studies Orléans 45071France

Rate coefficients for the reaction of N03 radicals with 6 unsaturated volatile organic compounds(VOCs) in a 7300 l simulation chamber at ambient temperature and pressure have been determined by the relative rate *** resulting rate coefficients were determined for isoprene,2-carene,3-carene,methyl vinyl ketone(MVK),methacrolein(MACR)and crotonaldehyde(CA),as(6.6±0.8)×10-13,(1.8±0.6)×10-11,(8.7±0.5)×10-12,(1.24±1.04)×10-16,(3.3±0.9)×10-15 and(5.7±1.2)×10-15 cm3/(molecule·sec),*** experiments indicate that NO3 radical reactions with all the studied unsaturated VOGs proceed through addition to the olefinic bond,however,it indicates that the introduction of a carbonyl group into unsaturated VOGs can deactivate the neighboring olefinic bond towards reaction with the NO3 radical,which is to be expected since the presence of these electronwithdrawing substituents will reduce the electron density in the π orbitals of the alkenes,and will therefore reduce the rate coefficient of these electrophilic addition *** addition,we investigated the product formation from the reactions of 2-carene and 3-carene with the NO3 *** identification of an epoxide(C10H16OH+),caronaldehyde(C10H16O2 H+) and nitrooxy-ketone(C10H16O4 NH+) was achieved using a proton transfer reaction time-of-flight mass spectrometer(PTR-TOF-MS) and a reaction mechanism is proposed.

关键词： Rate coefficient NO_(3) radical Products Volatile organic compounds(VOCs)

A New Paradigm for the Extraction of Information: Application to Enhancement of Visual Information in a Medical Application

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Journal of Donghua University(English Edition) 2004年第3期21卷 111-116页

作者： V. Courboulay A. Histace M. Ménard C. Cavaro-Ménard laboratoire l3i Ple Sciences et Technologie Université de La Rochelle 17032 La Rochelle Cedex FanceLaboratoire d' Ingénierie des Systèmes Automatisés 62 avenue Notre Dame du Lac 49000 Angers FranceLaboratoire L3i Ple Sciences et Technologie Université de La Rochelle 17032 La Rochelle Cedex FanceLaboratoire d' Ingénierie des Systèmes Automatisés 62 avenue Notre Dame du Lac 49000 Angers France

The noninvasive evaluation of the cardiac function presents a great interest for the diagnosis of cardiovascular diseases. Tagged cardiac MRI allows the measurement of anatomical and functional myocardial parameters. This protocol generates a dark grid which is deformed with the myocardium displacement on both Short-Axis (SA) and long-Axis (lA) frames in a time sequence. Visual evaluation of the grid deformation allows the estimation of the displacement inside the myocardium. The work described in this paper aims to make robust and reliable the visual enhancement of the grid tags on cardiac MRI sequences, thanks to an informational formalism based on Extreme Physical Informational (EPI). This approach leads to the development of an original diffusion pre-processing allowing us to make better the robustness of the visual detection and the following of the grid of tags.

关键词： Tagged MRI Pde anisotropic diffusion Extreme Physical Information (EPI)

Composition, Stability and Probable Structure of a Colourless Organometallic Complex (Gd(III)-Malic Acid)

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Open Journal of Physical Chemistry 2013年第1期3卷 49-58页

作者： Mohammed Riri Oussama Kamal Abdelkhalek Benjjar Farid Serdaoui Miloudi Hlaibi laboratoire d’Interface Matériaux et Chimie de l’environnement UniversitéHassan II Facultédes Sciences Ain ChockCasablancaMaroc laboratoire des Polymères BiopolymèresSurfacesFacultédes SciencesUniversitéde RouenRouenFrance

The formation of colourless gadolinium complexes (x,y,z), between x gadolinium ions, y ligands and z protons, of some organic acids, has been studied in aqueous solution. In this work we present the results of investigations on the interaction of the gadolinium ion (Gd3+) with malic acid (C4H6O5, a-hydroxyl dicarboxylic acid), in dilute aqueous solution for pH values between 5.5 and 7.5. Colourless gadolinium complexes of malate ions have no absorption band UV-visible, the indirect photometric detection (IPD) technique was used and studies have identified a major tri-nuclear complex of malate ion (﹣OOC-CH2-CHOH-COO﹣). The formation of this new colourless complex is derived from three Gd(III) ions that react with two malate ions and two hydronium ions (H3O+), giving for this colourless complex, a (3,2,2) composition and apparent stability constant depends on the acidity of the medium, with logK'322 = 18.88 ± 0.05 at pH = 6.30. To complement previous results and to propose a probable structure for this new complex detected in solution, studies of IR spectroscopy have been conducted to identify the chelation sites for both ligands. The results were analysed and show that this organometallic gadolinium complex, contains two different sites, respectively, two lateral tetradentate mono-nuclear sites and a single central bidentate mono-nuclear site. From these results, the reaction of formation, the stability constant and the probable structure of this new colourless organometallic gadolinium complex are proposed.

关键词： Gadolinium Complexes Malate Ions Indirect Photometric detection(IPD) Apparent Stability Constant Chelation Sites Bidentate Mono-Nuclear Tetradentate Mono-Nuclear

Free vibration of functionally graded sandwich plates using four-variable refined plate theory

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Applied Mathematics and Mechanics(English Edition) 2011年第7期32卷 925-942页

作者： l.HADJI H.A.ATMANE A.TOUNSI I.MECHAB E.A.ADDA BEDIA laboratoire des Matériaux et Hydrologie Université de Sidi Bel AbbesSidi Bel Abbes 22000Algérie Département de Génie Civil Université Ibn KhaldounTiaret 14000Algérie Département de Génie Civil Faculté des Sciences de l'IngénieurUnivesité Hassiba Benbouali de ChlefChlef 02000Algérie

This paper uses the four-variable refined plate theory （RPT） for the free vibration analysis of functionally graded material （FGM） sandwich rectangular plates. Unlike other theories, there are only four unknown functions involved, as compared to five in other shear deformation theories. The theory presented is variationally consistent and strongly similar to the classical plate theory in many aspects. It does not require the shear correction factor, and gives rise to the transverse shear stress variation so that the transverse shear stresses vary parabolically across the thickness to satisfy free surface conditions for the shear stress. Two common types of FGM sandwich plates are considered, namely, the sandwich with the FGM facesheet and the homogeneous core and the sandwich with the homogeneous facesheet and the FGM core. The equation of motion for the FGM sandwich plates is obtained based on Hamilton＇s principle. The closed form solutions are obtained by using the Navier technique. The fundamental frequencies are found by solving the eigenvalue problems. The validity of the theory is shown by comparing the present results with those of the classical, the first-order, and the other higher-order theories. The proposed theory is accurate and simple in solving the free vibration behavior of the FGM sandwich plates.

关键词： functionally graded material (FGM) free vibration sandwich plate refinedplate theory (RPT) Navier solution