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21.
Multivalent Interactions between an Aromatic Helical Foldamer and a DNA G‐Quadruplex in the Solid State 下载免费PDF全文
Dr. Pradeep K. Mandal Dr. Benoît Baptiste Dr. Béatrice Langlois d'Estaintot Dr. Brice Kauffmann Dr. Ivan Huc 《Chembiochem : a European journal of chemical biology》2016,17(20):1911-1914
Quinoline‐based oligoamide foldamers have been identified as a potent class of ligands for G‐quadruplex DNA. Their helical structure is thought to target G‐quadruplex loops or grooves and not G‐tetrads. We report a co‐crystal structure of the antiparallel hairpin dimeric DNA G‐quadruplex (G4T4G4)2 with tetramer 1 —a helically folded oligo‐quinolinecarboxamide bearing cationic side chains—that is consistent with this hypothesis. Multivalent foldamer–DNA interactions that modify the packing of (G4T4G4)2 in the solid state are observed. 相似文献
22.
Jean-Luc Caillaud Stphane Deguillaume Michel Vincent Jean-Claude Giannotta Jean-Michel Widmaier 《Polymer International》1996,40(1):1-7
The addition of metallic fillers is recognized to impart improvement of acoustic properties to polyurethane-based materials used for marine applications. The system under consideration was obtained by the reaction of a triisocyanateterminated prepolymer with 1,4-butanediol, in the presence of various concentrations of lead powder. With increasing lead content, gelation time is reduced and an Einstein-type law does not apply. The kinetics of the reaction were determined by Fourier transform infrared spectroscopy. Deviation from the classic second order is observed for the filled systems, and the higher the lead content, the more important the deviation is, showing undoubtedly the catalytic effect of the metallic powder. 相似文献
23.
Davide Slaghenaufi Stéphanie Marchand-Marion Tristan Richard Pierre Waffo-Teguo Jonathan Bisson Jean-Pierre Monti Jean-Michel Merillon Gilles de Revel 《Food chemistry》2013
Flavours extracted from oak wood during barrel ageing contribute to the organoleptic character of wines and spirits. The aim of this work was to identify the glycosidic precursors of the key volatile compounds responsible for oak wood aroma. Oak extract is a very complex matrix and, furthermore, precursors are present in very small quantities. Preparative centrifugal partition chromatography (CPC) is a promising solution for purifying the oak extract. The solvent system was selected on the basis of the partition coefficient of glycosidase enzyme activity (Kca). Thanks to the efficacy of CPC separation, three glucoside gallates were subsequently isolated by HPLC chromatography. Vanillin-(6′-O-galloyl)-O-β-d-glucopyranoside, 3,4,5-trimethoxyphenyl-(6′-O-galloyl)-O-β-d-glucopyranoside, and (6R,9R)-3-oxo-α-ionol-9-O-(6′-O-galloyl)-β-glucopyranoside (macarangioside E) were isolated and identified. This was the first time that vanillin-(6′-O-galloyl)-O-β-d-glucopyranoside was identified and the first time that macarangioside E was isolated from oak wood. Heating macarangioside E resulted in the formation of megastigmatrienone, which has an aroma reminiscent of tobacco. 相似文献
24.
Blanc F Bernard H Alessandri S Bublin M Paty E Leung SA Patient KA Wal JM 《Molecular nutrition & food research》2008,52(Z2):S166-S175
Highly purified allergens namely cow's milk alpha-lactalbumin (ALA). (Bos d 4), beta-lactoglobulin (BLG) (Bos d 5) and casein (Bos d 8) and goat's milk casein were prepared from the raw milk from a single animal with a known genetic background. Consequently the natural isoforms are limited, constant and characterized. Purification included selective precipitations and chromatographical steps. Characterization of structure and allergenic activity assessment of milk allergens were carried out using physicochemical and immunochemical methods. Taken together data demonstrated the absence of impurities and of contamination by other milk allergens in each preparation. NMR and circular dichroism analyses confirmed the native conformation and proper folding of ALA and BLG and the expected absence of folding of bovine and caprine casein. Enzyme immuno assays confirmed the native conformation of BLG and the purity and immunoreactivity of all the proteins. The allergenic activity, e. g. the IgE binding capacity, of purified proteins was identical as that of those proteins when present in milk. The purified proteins also demonstrated the ability to provoke the degranulation of humanized rat basophilic leukaemia cells. All the data thus confirm the purity, identity, structural conformation and functionality of the prepared milk allergens. 相似文献
25.
Benoit Igne Jean-Michel Roger Sylvie Roussel Vronique Bellon-Maurel Charles R. Hurburgh 《Chemometrics and Intelligent Laboratory Systems》2009,99(1):57-65
Eight calibration transfer methods based on the removal of orthogonal signal were compared for the standardization of whole soybean protein and oil models. Dynamic orthogonal projection (DOP), transfer by orthogonal projection (TOP), error removal by orthogonal subtraction (EROS), orthogonal signal correction (OSC), and orthogonal projections to latent structures (O-PLS) as well as the modification and extension of some of these methods were compared in the transfer of models in intra and inter-brand situations using two Foss Infratecs and two Bruins OmegAnalyzerGs. For each brand, a master was designated and its models transferred onto the second unit of its network and the two units of the second brand. Calibration models were transferable from brand to brand with similar or better precision than when each instrument was calibrated on its own calibration set (for Infratec 1229, the relative predictive determinant (RPD) increased in intra and inter-brand calibration transfer situations from 10.42 to 11.45 and 10.57, with DOP and EROS respectively). Performance of each method was different across parameters, instruments, and validation sets. DOP modifications on the determination of the difference matrix showed promising results while TOP and EROS extensions to include variability specifically present in certain crop years did not bring any beneficial effects. 相似文献
26.
Clotilde Minfray Thierry Le Mogne Jean-Michel Martin Tasuku Onodera Sayaka Nara Shuko Takahashi 《摩擦学汇刊》2013,56(5):589-601
Zinc phosphate glass is considered to be the main constituent of tribofilms generated under boundary lubrication with zinc dialkyldithiophosphate (ZDDP), a well-known antiwear additive. The reaction occurring during friction between zinc phosphate glasses and steel native iron oxide layer is investigated by both an experimental approach and by Molecular Dynamics simulations (MD). The importance of this “tribochemical” reaction in the general ZDDP antiwear process is discussed. 相似文献
27.
Jean-Michel Lamarre Pierre Marcoux Michel Perrault Richard C. Abbott Jean-Gabriel Legoux 《Journal of Thermal Spray Technology》2013,22(6):947-953
Many processes and systems require hot surfaces. These are usually heated using electrical elements located in their vicinity. However, this solution is subject to intrinsic limitations associated with heating element geometry and physical location. Thermally spraying electrical elements directly on surfaces can overcome these limitations by tailoring the geometry of the heating element to the application. Moreover, the element heat transfer is maximized by minimizing the distance between the heater and the surface to be heated. This article is aimed at modeling and characterizing resistive heaters sprayed on metallic substrates. Heaters were fabricated by using a plasma-sprayed alumina dielectric insulator and a wire flame-sprayed iron-based alloy resistive element. Samples were energized and kept at a constant temperature of 425 °C for up to 4 months. SEM cross-sectional observations revealed the formation of cracks at very specific locations in the alumina layer after thermal use. Finite-element modeling shows that these cracks originate from high local thermal stresses and can be predicted according to the considered geometry. The simulation model was refined using experimental parameters obtained by several techniques such as emissivity and time-dependent temperature profile (infra-red camera), resistivity (four-probe technique), thermal diffusivity (laser flash method), and mechanical properties (micro and nanoindentation). The influence of the alumina thickness and the substrate material on crack formation was evaluated. 相似文献
28.
Fabrice Rigaud Jean-Michel Portal Didier Nee Fabrice Argoud 《Microelectronics Reliability》2011,51(6):1136-1141
The objective of this paper is to present a mixed test structure designed to characterize yield losses due to hard defect and back-end process variation (PV) at die and wafer level. A brief overview of the structure, designed using a ST-Microelectronics’ 130 nm technology, is given. This structure is based on a SRAM memory array for detecting hard defects. Moreover each memory cell can be configured in the Ring Oscillator (RO) mode for back-end PV characterization. The structure is tested in both modes (SRAM, RO) using a single test flow. The test data analysis method is presented and applied to experimental results to confirm the ability of the structure to monitor PV and defect density. 相似文献
29.
André Lecomte Jean-Michel Mechling Cécile Diliberto 《Construction and Building Materials》2009,23(10):3279-3286
Knowing the virtual packing densities of all the components in a mixture is necessary to calculate its granular packing density with the compressible packing model. The calculation of these virtual packing densities is based on real packing density measurements carried out according to specific operating modes, each one with a different compaction index K. For powders, the current method consists in adding water to powder in a mixer until obtaining a smooth paste (K = 6.7). But this method remains subjective since the degree of smoothness achieved is estimated by the operator. The objective of this work is to put forward a more rational alternative method based on tests of normal consistency used in cement plants. This paper presents experiments on binary mixtures (cement–mineral admixtures), with or without superplasticizer, which have resulted in a compaction index K = 4.8. Using these results, the amount of water (given in the technical data sheet) needed to obtain a normal consistency allows the calculation of virtual packing densities of standardized cements. However, if a superplasticizer is used it is necessary to carry out this test. Its saturation proportion can also be estimated with the test of normal consistency. 相似文献
30.
Paule Njiwa Clotilde Minfray Thierry Le Mogne Béatrice Vacher Jean-Michel Martin Shigeki Matsui Masaru Mishina 《Tribology Letters》2011,44(1):19-30
In this study, we are interested in the anti-wear properties of zinc dialkyl phosphate additive (ZP) in comparison with ‘classical’ zinc dialkyldithiophosphate (ZDDP). Friction tests were performed on a reciprocating tribometer using both ball-on-flat and cylinder-on-flat configurations
under a Hertzian contact pressure of 0.9 GPa. Experiments were carried out as a function of temperature (25 and 100 °C), sliding
speed (25, 50 and 100 mm/s) and additives concentrations. Ball wear scar diameters as well as friction coefficient were measured.
In order to better understand the anti-wear mechanisms of these additives, friction tests were followed by surface analyses
such as AES (Auger Electron Spectroscopy) and XPS (X-Ray Photoelectron Spectroscopy). Transmission Electron Microscopy (TEM)
observations of the ZDDP and ZP tribofilms were also carried out to visualise the generated layers. The anti-wear capability of ZP molecule is discussed. 相似文献