Search results for "RAV"
showing 10 items of 5866 documents
Paramagnetic NMR investigations of Co(II) and Ni(II) amicyanin.
1999
The paramagnetic 1H NMR spectra of the Co(II) and Ni(II) substituted forms of the type 1 blue copper protein (cupredoxin) amicyanin have been assigned. This is the first such analysis of a cupredoxin, which has a distorted tetrahedral active site with the ligands provided by two histidines, a cysteine and a methionine. The isotropic shifts of the resonances in these spectra are compared with those of Co(II) and Ni(II) azurin. A number of interesting similarities and differences are found. The coordination of the metal by the two equatorial histidine ligands is very similar in both proteins. The interaction between the introduced metal and the thiolate sulfur of the equatorial cysteine ligan…
Suitability of 1-hexyl-3-methylimidazolium ionic liquids for the analysis of pharmaceutical formulations containing tricyclic antidepressants
2018
Abstract The reversed-phase chromatographic behaviour of six tricyclic antidepressants (amitryptiline, clomipramine, doxepin, imipramine, nortryptiline and maprotiline) was examined in this work with acetonitrile-water mobile phases, in the absence and presence of the ionic liquids 1-hexyl-3-methylimidazolium chloride and 1-hexyl-3-methylimidazolium tetrafluoroborate, which have interesting features for the separation of basic compounds, in terms of peak shape combined with reduced retention. Tricyclic antidepressants are low polarity drugs that strongly associate to the alkyl chains of conventional stationary phases. They are also positively charged in the usual working pH range (2–8) in r…
Collision de similaritons optiques dans un amplificateur optique fibré Raman
2005
National audience; Nous abordons les aspects théoriques et expérimentaux de la génération et propagation de deux similaritons optiques de fréquences centrales différentes dans un amplificateur optique fibré Raman à dispersion normale. Nous observons les effets intervenant durant la collision des deux similaritons: un battement sinusoïdal apparaît dans la zone de recouvrement temporel des impulsions et des effets de la modulation de phase croisée modifient le spectre des similaritons. Les similaritons retrouvent néanmoins, après collision, leurs caractéristiques paraboliques.
Fourier integral operators and inhomogeneous Gevrey classes
1988
Fourier integral operators with inhomogeneous amplitude and phase junction are studied in the frame of Gevrey classes. Applications are given to propagation of singularities for a pseudodifferential equation.
Thioflavin T Hydroxylation at Basic pH and Its Effect on Amyloid Fibril Detection
2008
The fluorescent dye thioflavin T (ThT) is commonly used for in situ amyloid fibril detection. In this work, we focused on the spectroscopic properties and chemical stability of ThT in aqueous solution as a function of pH, temperature, and dye concentration. A reversible hydroxylation process occurs in alkaline solutions, which was characterized using a combination of UV-vis absorption spectroscopy, proton NMR, and density functional theory (DFT). On the basis of these studies, we propose a chemical structure for the hydroxylated form. Finally, by means of fluorescence spectroscopy, ThT hydroxylation effects on in situ amyloid detection have been investigated, providing new insights on the e…
The Raven's Coloured Progressive Matrices in Healthy Children: A Qualitative Approach
2020
Studies on the structure of intelligence refer to two main theoretical models: the first one considers intelligence as a unitary construct, the second one assumes the involvement of a plurality of factors. Studies using Raven’s Coloured Progressive Matrices (RCPM) tasks have often highlighted the involvement of different cognitive abilities and brain structures, but in the clinical setting, RCPM measurement continues to be used as a single score. The current study aimed to analyse the RCPM performance following qualitative clustering, in order to provide an interpretation of the intelligence assessment through a factorial criterion. The RCPM have been administered to a large group of typica…
Réussite scolaire, réussite professionnelle, l'apport des données longitudinales XXIes journées d'étude sur les données longitudinales dans l'analyse…
2014
International audience; Dans un contexte où s'accumulent les difficultés scolaires au sein du système éducatif, puis les difficultés professionnelles sur un marché du travail de plus en plus sélectif, la question de la réussite se pose souvent en creux dans les interrogations de nombreux chercheurs. Elle constitue le thème central de ces XXIes journées du longitudinal.
Development of immunoaffinity columns for pyraclostrobin extraction from fruit juices and analysis by liquid chromatography with UV detection
2010
Abstract Pyraclostrobin belongs to a new generation of fungicides widely used to preserve high valuable crops. In the present study, three monoclonal antibodies with different affinities to this modern strobilurin have been evaluated for their usefulness in the production of immunoaffinity columns suitable for the solid-phase extraction, concentration, and clean-up of residues from food commodities. Different immunosorbents were produced and characterized in terms of antibody immobilization efficiency, immunosorbent binding capacity, optimum elution conditions, and reusability. Covalent coupling of the antibodies to Sepharose–CNBr gel took place with high yield (over 90%), whereas the immun…
Selective determination of trimethylamine in air by liquid chromatography using solid phase extraction cartridges for sampling.
2004
Abstract The selective determination of trimethylamine (TMA) in air by liquid chromatography is reported. Sampling is effected by flushing air through C18-packed solid-phase extraction (SPE) cartridges at a flow rate of 15 mL/min for 15 min. Next, TMA is desorbed from the cartridges and injected into the chromatographic system. The analyte is then selectively retained on a precolumn ( 20 mm ×2.1 mm i.d., packed with 30 μm, Hypersil C18 phase), and derivatized on-line by injecting 9-fluorenylmethyl chloroformate (FMOC). Finally, the TMA-FMOC derivative is transferred to the analytical column ( 125 mm ×4 mm i.d., LiChrospher 100 RP18, 5 μm), and monitored at 262 nm. The method was applied to …
Diffusion technique for the generation of gaseous halogen standards
2009
Abstract Halogens are known to play an important role in the tropospheric ozone-depletion chemistry and are of special interest because of their influence on the atmospheric oxidation capacity. In this paper, we investigate the application of a capillary diffusion technique for the generation of gaseous halogen standards like Br 2 , IBr, ICl and I 2 . The influence of capillary dimension (i.e. length and inner diameter), ambient pressure and headspace volume of the diffusion vessel on the test gas output has been evaluated. The experimental output rates are determined from the mass loss of the analyte vessel on a regular schedule and compared with their respective theoretical predictions. W…