Search results for "Meri"

Optimisation of chromatographic resolution using objective functions including both time and spectral information.

2014

The optimisation of the resolution in high-performance liquid chromatography is traditionally performed attending only to the time information. However, even in the optimal conditions, some peak pairs may remain unresolved. Such incomplete resolution can be still accomplished by deconvolution, which can be carried out with more guarantees of success by including spectral information. In this work, two-way chromatographic objective functions (COFs) that incorporate both time and spectral information were tested, based on the peak purity (analyte peak fraction free of overlapping) and the multivariate selectivity (figure of merit derived from the net analyte signal) concepts. These COFs are s…

Multivariate optimization approach for chiral resolution of drugs using human serum albumin in affinity electrokinetic chromatography-partial filling…

2005

The enantiomeric resolution of chiral compounds using HSA by means of affinity EKC (AEKC)-partial filling technique is the result of a delicate balance between different experimental variables such as protein concentration, running pH (background electrophoretic buffer, protein and compound solutions) and protein solution plug length. In this paper multivariate optimization approaches for chiral separation of four basic drugs (alprenolol, oxprenolol, promethazine and propranolol) using HSA as chiral selector in AEKC-partial filling technique are studied. The experimental conditions to achieve maximum resolution are optimized using the Box-Behnken experimental design. Partial least squares a…

Strategies for the enantiomeric determination of amphetamine and related compounds by liquid chromatography.

2002

This paper summarizes recent research on the stereospecific analysis of amphetamine, its analogs and metabolites, by liquid chromatography. The different methods proposed have been evaluated and compared in terms of resolution power, time of analysis, sensitivity, or potential for automation. Chiral derivatization, followed by separation of the diastereomers formed in achiral chromatographic systems, is still the method preferred for the analysis of amphetamines at trace levels, as derivatization also improves analyte detectability. This is the method of choice for the enantiomeric analysis of amphetamines at the low concentrations typically encountered in biological samples. In recent year…

Generation of TCR-Engineered T Cells and Their Use To Control the Performance of T Cell Assays

2015

Abstract The systematic assessment of the human immune system bears huge potential to guide rational development of novel immunotherapies and clinical decision making. Multiple assays to monitor the quantity, phenotype, and function of Ag-specific T cells are commonly used to unravel patients’ immune signatures in various disease settings and during therapeutic interventions. When compared with tests measuring soluble analytes, cellular immune assays have a higher variation, which is a major technical factor limiting their broad adoption in clinical immunology. The key solution may arise from continuous control of assay performance using TCR-engineered reference samples. We developed a simp…

Headspace–mass spectrometry determination of benzene, toluene and the mixture of ethylbenzene and xylene isomers in soil samples using chemometrics

2007

A simple and fast method has been developed for the determination of benzene, toluene and the mixture of ethylbenzene and xylene isomers (BTEX) in soils. Samples were introduced in 10 mL standard glass vials of a headspace (HS) autosampler together with 150 microL of 2,6,10,14-tetramethylpentadecane, heated at 90 degrees C for 10 min and introduced in the mass spectrometer by using a transfer line heated at 250 degrees C as interface. The volatile fraction of samples was directly introduced into the source of the mass spectrometer which was scanned from m/z 75 to 110. A partial least squares (PLS) multivariate calibration approach based on a classical 3(3) calibration model was build with m…

Pressure-induced magnetic switching and linkage isomerism in K0.4Fe4[Cr(CN)6]2.8 x 16 H2O: X-ray absorption and magnetic circular dichroism studies.

2008

The effect of applied pressure on the magnetic properties of the Prussian blue analogue K0.4Fe4[Cr(CN)6]2.8 x 16 H2O (1) has been analyzed by dc and ac magnetic susceptibility measurements. Under ambient conditions, 1 orders ferromagnetically at a critical temperature (T(C)) of 18.5 K. Under application of pressure in the 0-1200 MPa range, the magnetization of the material decreases and its critical temperature shifts to lower temperatures, reaching T(C) = 7.5 K at 1200 MPa. Pressure-dependent Raman and Mossbauer spectroscopy measurements show that this striking behavior is due to the isomerization of some Cr(III)-C[triple bond]N-Fe(II) linkages to the Cr(III)-N[triple bond]C-Fe(II) form. A…

Spectroscopic Detection and Structure of Hydroxidooxidosulfur (HOSO) Radical, An Important Intermediate in the Chemistry of Sulfur-Bearing Compounds

2013

The rotational spectrum of hydroxidooxidosulfur, HOSO, an intermediate of particular interest in the combustion of sulfur-rich fuels, has been determined to high accuracy from gas-phase measurements. Detection of specific isotopic species using isotopically enriched gases suggests that HOSO is formed in our discharge nozzle via the reaction H + SO2 (+M) → HOSO (+M). A precise experimental r0 geometry has also been derived from the isotopic analysis; HOSO has a cis configuration, but the subtle structural question of its planarity remains unresolved. From the derived spectroscopic constants, in situ and remote sensing for this fundamental radical can now be undertaken in a variety of environ…

An improved numerical solver of the 2D diffusive shallow waters equations over unstructured triangular meshes

2009

Ideas and lives across the Atlantic. The American Anarchism in the Galician libertarian press

2019

In this article we will analyse, from a transnational history point of view, the presence of American anarchism in the Galician libertarian press until 1936. In the 19th and 20h centuries, the transatlantic migrations contributed to develop a dense network of contacts and relationships between Galicia and American countries. This network involves anarchist militants on both sides of the Ocean. The Galician anarchists have a close collaboration with her Americans libertarian comrades; and many Galician militants are actively committed in the labour movement of their host countries. The Galician libertarian press shows this relationship and this participation in different ways (articles, cont…

Polyacrylonitrile block copolymers for the preparation of a thin carbon coating around TiO2 nanorods for advanced lithium-ion batteries.

2013

Herein, a new method for the realization of a thin and homogenous carbonaceous particle coating, made by carbonizing RAFT polymerization derived block copolymers anchored on anatase TiO2 nanorods, is presented. These block copolymers consist of a short anchor block (based on dopamine) and a long, easily graphitizable block of polyacrylonitrile. The grafting of such block copolymers to TiO2 nanorods creates a polymer shell, which can be visualized by atomic force microscopy (AFM). Thermal treatment at 700 °C converts the polyacrylonitrile block to partially graphitic structures (as determined by Raman spectroscopy), establishing a thin carbon coating (as determined by transmission electron m…