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151.
Ropartz D Bodet PE Przybylski C Gonnet F Daniel R Fer M Helbert W Bertrand D Rogniaux H 《Rapid communications in mass spectrometry : RCM》2011,25(14):2059-2070
Compared to other analytical methods, matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) presents several unique advantages for the structural characterization of degradation products of carbohydrates. Our final goal is to implement this technique as a high-throughput platform, with the aim of exploring natural bio-diversity to discover new carbohydrate depolymerizing enzymes. In this approach, a variety of carbohydrates will be used as enzymes substrates and MALDI-MS will be employed to monitor the oligosaccharides produced. One drawback of MALDI, however, is that the choice of the matrix is largely dependent on the chemical properties of the analyte. In this context, our objective in the present work was to find the smallest set of MALDI matrices able to detect chemically heterogeneous oligosaccharides. This was done through the performance evaluation of more than 40 MALDI matrices preparations. Homogeneity of analyte-matrix deposits was considered as a critical feature, especially since the final objective is to fully automate the analyses. Evaluation of the matrices was done by means of a rigorous statistical approach. Amongst all tested compounds, our work proposes the use of the DHB/DMA ionic matrix as the most generic matrix, for rapid detection of a variety of polysaccharides including neutral, anionic, methylated, sulfated, and acetylated compounds. The selected matrices were then used to screen crude bacterial incubation media for the detection of enzymatic degradation products. 相似文献
152.
The radical carbozincation of diethyl acetylenedicarboxylate, performed at room temperature in the presence of air, leads to fumaric derivatives through a selective alkylzinc group radical transfer controlled by coordination. The total trans stereocontrol is unprecedented, carbocupration is well-known to give the reversal selectivity at low temperature, while classical radical addition methodologies lead to mixtures of isomers. 相似文献
153.
H. Bahaj M. Bakass C. Bayane J. P. Bellat M. Benchanaa G. Bertrand 《Journal of Thermal Analysis and Calorimetry》2011,103(1):117-123
The adsorbed amounts of water vapor onto polyacrylic polymer (polymer ×10) were measured using a thermogravimetry method as
a function of pressure at 298 and 313 K. The adsorption isotherms are categorized to type II isotherms by IUPAC classification
leading to a hysteresis loop between adsorption and desorption branches. The current study was completed by the measurement
of the adsorption heats at 298 K using a differential scanning calorimetry. The calorimetric curves showed two adsorption
heats domains. These domains have been attributed to the adsorption of “equivalent monolayer” and the condensation of water
between polymeric chains. The correlation of experimental data to some chosen theoretical models shows that the GAB model
is the most adequate to describe water vapor sorption isotherms. 相似文献
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155.
Bertrand Parvitte Christophe Risser Raphael Vallon Virginie Zéninari 《Applied physics. B, Lasers and optics》2013,111(3):383-389
This paper aims to demonstrate the quantitative simulation of photoacoustic signals using finite element modelling software. The software Comsol Multiphysics is used to calculate the response of a differential Helmholtz resonator cell previously modeled using an electrical analogy. Quality factors and resonance frequencies are compared with experimental ones. Moreover, for the first time, the absorption coefficient of the gas sample and the laser intensity are also used to quantitatively predict photoacoustic signal that can be obtained in such a configuration. 相似文献
156.
H. B. Knowles L. H. James Th. R. Cunningham H. L. Hamner W. Brüggemann C. M. Johnson E. Bertrand H. C. Weirick C. H. Mc Collam J. V. Tamchyna C. Montelucci M. Gambioli L. Spiegel Th. M. Maas E. Montignie H. Hauptmann M. Balconi E. Carriére R. Lautié Z. Raichinstein N. Korobow J. F. Sacher 《Analytical and bioanalytical chemistry》1934,98(9-10):362-374
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G. Bertrand 《Fresenius' Journal of Analytical Chemistry》1913,52(9):580-581
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