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101.
Laurent Hollecker Maurizio Pinna Giorgia Filippino Stefania Scrugli Barbara Pinna Francesca Argiolas Mariano Murru 《Journal of chromatography. A》2009,1216(15):3402-3408
A new method for the identification and the quantification of nonanthocyanin phenolic compounds from six Vitis Vinifera grape varieties native to Sardinia (three native: Vermentino, Malvasia and Cannonau and three non-native types: Chardonnay, Sauvignon and Cabernet Sauvignon; Argiolas vineyard) was developed. This rapid and selective method employs LC/ESI-MS in negative mode. Different solvents extraction and different sorbents for purification were compared to the direct analysis of the initial extracts without further sample preparation. A total of 54 phenolic compounds were identified either in the freeze-dried skins or seeds, including nonflavonoids (hydroxybenzoic and hydroxycinnamic acids and their derivatives, stilbenes) and flavonoids (flavanols, flavonols, dihydroxyflavonols). 相似文献
102.
We wish to present herein a simple one-pot synthesis of 2,5-disubstituted oxazoles, starting from benzyl halides and acyl chlorides. The in situ formation of isocyanides, followed by the addition of an acyl chloride in the presence of a base leads to the desired oxazoles in good yields. 相似文献
103.
Laurent El Kaïm Laurence Grimaud Julie Oble Simon Wagschal 《Tetrahedron letters》2009,50(15):1741-2444
Cyclic imines react with isocyanides and electron-deficient phenols to afford N-aryl piperidines and pyrrolidines in good yields (Ugi-Smiles couplings of cyclic imines). The starting imines were formed by oxidation with N-chlorosuccinimide followed by a base-induced dehydrochlorination. 相似文献
104.
In this paper, we present the methodology and the results obtained by the gravimetric and the FTIR methods to study the sorption of amyl acetate in polypropylene packaging. The influence of the concentration of amyl acetate and the temperature of aging on the sorption is discussed. A non-Fickian model is used to determine the diffusion coefficient and the surface mass transfer coefficient and their evolution with the amyl acetate concentration and the temperature of aging. The effect of the diffusion of amyl acetate on the polypropylene is studied by means of thermal properties. 相似文献
105.
Laurent A. Baumes 《Tetrahedron letters》2009,50(50):7001-7980
A colorimetric sensor array based on supramolecular host-guest complexes has been developed for the identification and quantification of quaternary ammonium salts (QAS). QAS are ubiquitous undesirable compounds for which the identification of the individual compounds is not trivial and needs instrumental techniques. The sensor array developed by us is constituted by host-guest complexes formed by the inclusion of tricyclic basic dyes such as proflavine, acridine orange, thionin, and methylene blue inside the hollow space defined by cucurbit[n]urils with n = 7 and 8. The operation of the sensor array has been demonstrated by differentiating 14 quaternary ammonium salts, some of them differing by a single carbon atom in the alkyl group. The detection limit concentration was 10−5 M and the system can also be used to quantify the concentration of the quaternary ammonium ion. 相似文献
106.
We give large deviation results for the super-Brownian excursion conditioned to have unit mass or unit extinction time and for super-Brownian motion with constant non-positive drift. We use a representation of these processes by a path-valued process, the so-called Brownian snake for which we state large deviation principles. 相似文献
107.
Masahisa Wada Laurent Heux Yoshiharu Nishiyama Paul Langan 《Cellulose (London, England)》2009,16(6):943-957
X-ray crystallographic and cross-polarization/magic angle spinning 13C nuclear magnetic resonance techniques have been used to study an ethylenediamine (EDA)-cellulose I complex, a transient structure in the cellulose I to cellulose IIII conversion. The crystal structure (space group P2 1 ; a = 4.546 Å, b = 11.330 Å, c = 10.368 Å and γ = 94.017°) corresponds to a one-chain unit cell with one glucosyl residue in the asymmetric unit, a gt conformation for the hydroxymethyl group, and one EDA molecule per glucosyl residue. Unusually, there are no O–H···O hydrogen bonds between the cellulose chains; the chains are arranged in hydrophobic stacks, stabilized by hydrogen bonds to the amine groups of bridging EDA molecules. This new structure is an example of a complex in which the cellulose chains are isolated from each other, and provides a number of insights into the structural pathway followed during the conversion of cellulose I to cellulose IIII through EDA treatment. 相似文献
108.
In this paper, we present some alternative definitions of Besov spaces of generalized smoothness, defined via Littlewood–Paley‐type decomposition, involving weak derivatives, polynomials, convolutions and generalized interpolation spaces. 相似文献
109.
Valérie Baco-Carles Isabelle Pasquet Véronique Laurent Armand Gabriel Philippe Tailhades 《Solid State Sciences》2009,11(8):1503-1506
Dense micro-cermets made of nickel ferrites and copper micrometric particles were obtained from partial reduction under hydrogenated atmosphere at 350 °C of mixed copper nickel ferrites, and sintering in nitrogen at 980 °C. The small copper particles are homogeneous in size and well dispersed in the spinel oxide matrix. No exudation of copper metal was observed after sintering. The micro-cermets prepared are semi-conducting materials with electrical conductivity lying from 44 to 130 S/cm at 980 °C. Their overall characteristics make them interesting for inert anodes dedicated to aluminium electrolysis in melted cryolite. 相似文献
110.
We consider multipoint Padé approximation to Cauchy transforms of complex measures. We show that if the support of a measure
is an analytic Jordan arc and if the measure itself is absolutely continuous with respect to the equilibrium distribution
of that arc with Dini-smooth nonvanishing density, then the diagonal multipoint Padé approximants associated with appropriate
interpolation schemes converge locally uniformly to the approximated Cauchy transform in the complement of the arc. This asymptotic
behavior of Padé approximants is deduced from the analysis of underlying non-Hermitian orthogonal polynomials, for which we
use classical properties of Hankel and Toeplitz operators on smooth curves. A construction of the appropriate interpolation
schemes is explicit granted the parametrization of the arc. 相似文献