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41.
42.
Karine L Marques Jo?o L M Santos Jo?o A Lopes José L F C Lima 《Analytical sciences》2008,24(8):985-991
An automated multi-pumping flow system is proposed for the simultaneous chemiluminometric determination of benserazide and levodopa using multivariate calibration methods. The developed methodology is based on chemiluminescence (CL) emission generated by the reaction of benserazide with luminol, and on a concurrent inhibiting effect of levodopa on this reaction. A multi-pumping flow system comprising multiple solenoid micro-pumps as the only active components was developed to implement a stopped-flow approach for signal acquisition and processing. Artificial neural networks were used to establish a relationship between the CL emission profile and the concentration of both drugs. The concentration values used to establish the experimental calibration samples were varied between 5 and 30 mg l(-1) for levodopa and between 2.5 and 20 mg l(-1) for benserazide. The proposed method was successfully applied to the simultaneous determination of levodopa and benserazide in pharmaceutical formulations combining both drugs. 相似文献
43.
Karine Herreyre Denis Boudreau 《Spectrochimica Acta Part B: Atomic Spectroscopy》2004,59(12):1927-1933
The spectral background from 281 to 285 nm in the laser-enhanced ionization (LEI) spectrum of aqueous samples containing easily ionized elements (EIE) at concentrations similar to those found in blood was investigated. A complex, structured spectral background was observed, which appears in the presence of Na or K, but does not match the spectral signature of either element. The same behavior was also observed for Li. It was established that this background originates from an energy transfer between laser-excited hydroxyl (OH) molecules and ground-state EIEs. The intensity of this spectral feature was found to increase with EIE concentration and applied electrode voltage. This unexpected source of spectral interference may complicate the determination of trace metals by LEI in the presence of EIEs, since it can not be prevented by simply avoiding interference from atomic lines. 相似文献
44.
45.
Karine Chamaillard S. Gerard Jennings Young Jun Yoon 《Journal of Quantitative Spectroscopy & Radiative Transfer》2010,111(5):753-771
A more realistic estimation of the scattering and hemispheric backscattering coefficients, σsp and σbsp, and their respective optical cross section, Csca and Cbk, of aerosol particles is presented on the basis of the exact resolution of the width of the size bins of the particle counter instruments when size distribution measurements are used, and, with the exact optical detector instruments ability. The scattering and hemispheric backscattering cross sections, Csca and Cbk, of the particles are averaged over the full size bins of the particle counter instrument, while these quantities are usually estimated only on the value of the mean geometric diameter of each size bin. Six instruments, the APS, ASASP-X, DMPS, FSSP-100, ELPI, and SMPS frequently used in particle size distribution measurements are reviewed, for spherical sea-salt particles at a wavelength λ=0.55 μm. The comparison using the conventional geometric mean diameter versus the use of the full size bin leads to large amount of errors for the optical cross section with non-negligible effects on their respective optical coefficients. The maximal accuracy expected for these optical quantities depend on the particle diameter as well as on the channel width of the instruments, and are also function of the angular detector probe used to measure them. 相似文献
46.
Mathilde Mougeot Karine Tribouley 《Annals of the Institute of Statistical Mathematics》2010,62(2):383-412
We propose a test procedure which compares the extreme value indices of two samples with heavy tail distributions. On a theoretical
point of view, we adopt the minimax nonparametric point of view. We exhibit the separating rate between the null hypothesis
and the alternative of our procedure. Next, we present a data driven test methodology and we evaluate its performance thanks
to an extensive simulation study. As a practical real-life application, we compare the risk behaviors of a panel of different
financial data. 相似文献
47.
The instant controlled pressure drop (DIC) technology enabled both the extraction of essential oil and the expansion of the matrix itself which improved solvent extraction. The sequential use of DIC and Ultrasound Assisted Extraction (UAE) triggered complementary actions materialized by supplementary effects. We visualized these combination impacts by comparing them to standard techniques: Hydrodistillation (HD) and Solvent Extraction (SE). First, the extraction of orange peel Essential Oils (EO) was achieved by HD during 4 h and DIC process (after optimization) during 2 min; EO yields was 1.97 mg/g dry material (dm) with HD compared to 16.57 mg/g dm with DIC. Second, the solid residue was recovered to extract antioxidant compounds (naringin and hesperidin) by SE and UAE. Scanning electron microscope showed that after HD the recovered solid shriveled as opposite to DIC treatment which expanded the product structure. HPLC analyses showed that the best kinetics and yields of naringin and hesperidin extraction was when DIC and UAE are combined. Indeed, after 1 h of extraction, DIC treated orange peels with UAE were 0.825 ± 1.6 × 10?2 g/g of dry material (dm) for hesperidin and 6.45 × 10?2 ± 2.3 × 10?4 g/g dm for naringin compared to 0.64 ± 2.7 × 10?2 g/g of dry material (dm) and 5.7 × 10?2 ± 1.6 × 10?3 g/g dm, respectively with SE. By combining DIC to UAE, it was possible to enhance kinetics and yields of antioxidant extraction. 相似文献
48.
Karine Chesnel Joshua J. Turner Mark Pfeifer Stephen D. Kevan 《Applied Physics A: Materials Science & Processing》2008,92(3):431-437
We motivate the use of coherent soft X-ray beams to study materials that exhibit complex nanoscale behaviors. A new beamline
and magnetic scattering end station that has been constructed and commissioned at the ALS will be described. Finally, we present
some initial results that indicate the performance of the beamline.
K. Chesnel now at Department of Physics, Brigham Young University, Provo, Utah, USA.
J.J. Turner now at Department of Physics, Stony Brook University, Stony Brook, New York, USA.
M. Pfeifer now at School of Physics La Trobe University, Melbourne, Australia. 相似文献
49.
Bertin Karine Klutchnikoff Nicolas Panloup Fabien Varvenne Maylis 《Statistical Inference for Stochastic Processes》2020,23(2):271-300
Statistical Inference for Stochastic Processes - We build and study a data-driven procedure for the estimation of the stationary density f of an additive fractional SDE. To this end, we also prove... 相似文献
50.
Ivan Scodeller Samir Mansouri Dr. Didier Morvan Dr. Eric Muller Dr. Karine de Oliveira Vigier Dr. Raphael Wischert Dr. François Jérôme 《Angewandte Chemie (International ed. in English)》2018,57(33):10510-10514
We report the synthesis of biomass‐derived functionalized aromatic chemicals from furfural, a building block nowadays available in large scale from low‐cost biomass. The scientific strategy relies on a Diels–Alder/aromatization sequence. By controlling the rate of each step, it was possible to produce exclusively the meta aromatic isomer. In particular, through this route, we describe the synthesis of renewably sourced meta‐xylylenediamine (MXD). Transposition of this work to other furfural‐derived chemicals is also discussed and reveals that functionalized biomass‐derived aromatics (benzaldehyde, benzylamine, etc.) can be potentially produced, according to this route. 相似文献