Quantification of the intensity of virgin olive oil sensory attributes by direct coupling headspace-mass spectrometry and multivariate calibration techniques.

The main sensory defects of virgin olive oils (rancid, vinegary, winey, muddy sediment, musty and vegetable water) and one positive attribute (fruity) characteristic of three monovarietal extra virgin olive oils (Arbequina, Picual and Frantoio) have been quantified using the direct coupling headspace-mass spectrometry. The results obtained were compared with those provided by the panel test for the same samples. Taking into account that no chromatographic separation exists, multivariate calibration techniques (partial least squares, PLS, and principal components regression, PCR) were used to create the appropriate models.

Determination of non-steroidal anti-inflammatory drugs in urine by combining an immobilized carboxylated carbon nanotubes minicolumn for solid-phase extraction with capillary electrophoresis-mass spectrometry.

Last years, the usefulness of the use of carbon nanotubes (CNTs) as sorbent material have been demonstrated for a wide variety of compounds. In this work, it has been demonstrated for first time that immobilized carboxylated single-walled carbon nanotubes (c-SWNTs) offer clear advantages over the use of CNTs. The higher adsorption capacity has been attributed to the special orientation of c-SWNTs molecules on the glass surface.

Bridging the gap between analytical R&D products and their use in practice.

Identifying the key stakeholders (viz. R&D centers, routine laboratories, clients and producers of analytical tools) and their mutual relationships in Analytical Science, and pinpointing the objects through which knowledge and technology can be transferred among them, can help one recognize the weaknesses in the links connecting 'ivory towers' and industry with a view to developing ways to bridge the existing gap between the two.

Vanguard/rearguard strategy for the evaluation of the degradation of yoghurt samples based on the direct analysis of the volatiles profile through headspace-gas chromatography-mass spectrometry.

A vanguard/rearguard analytical strategy for the monitoring of the degradation of yoghurt samples is proposed. The method is based on the headspace-gas chromatography-mass spectrometry (HS-GC-MS) instrumental coupling. In this combination, the chromatographic column is firstly used as an interface between the HS and the MS (vanguard mode) avoiding separation of the volatile components by maintaining the chromatographic oven at high, constant temperature.

Continuous flow configuration for total hydrocarbons index determination in soils by evaporative light scattering detection.

A continuous flow configuration is proposed for the estimation of the hydrocarbon index in soils using for the first time evaporative light scattering detection (ELSD). The method is based on a membrane-enrichment of the hydrocarbons of interest (C10-C40), which are previously extracted from the soil matrix with a water:hexane mixture using a household microwave oven. The organic supernatant is cleaned-up through silica, evaporated and redissolved in a sodium dodecyl sulphate aqueous solution which is introduced in the loop of an injection valve.

Separation of carbon nanotubes in aqueous medium by capillary electrophoresis.

A robust and reproducible method for the dispersion of carbon nanotubes, either single-walled or multi-walled is presented. Dispersion of nanotubes was achieved as surfactant-coated species of sodium dodecyl sulphate. The addition of small amounts of hydroxypropyl methyl cellulose (HPMC) together with the surfactant, sodium dodecyl sulphate, was found critical to achieve reproducible nanotubes dispersion and to obtain an homogeneous and stable solution.

Effects of long-term adrenalectomy on apoptosis and neuroprotection in the rat hippocampus.

Reduction in corticosterone by acute adrenalectomy (5 d) promotes apoptosis in dentate gyrus (DG) granular neurons, an effect concomitant with variations in the expression of the Bcl-2 gene family implicated in apoptotic regulation. However, no studies exist correlating the effect of long-term adrenalectomy (30 d) on the hippocampus in terms of extent of apoptosis and the levels of proteins related to an apoptotic cascade. After 5 d of adrenalectomy, we found an increase in apoptosis of the DG granular region, correlated with an increase in the processing of caspase-9.

ATR-FTIR membrane-based sensor for the simultaneous determination of surfactant and oil total indices in industrial degreasing baths.

Monitoring the exhaustion of alkaline degreasing baths is one of the main aspects in metal mechanizing industrial process control. The global level of surfactant, and mainly grease, can be used as ageing indicators. In this paper, an attenuated total reflection-Fourier transform infrared (ATR-FTIR) membrane-based sensor is presented for the determination of these parameters.

Continuous autoanalyzer for the evaluation of the exhaustion of industrial degreasing baths based on the determination of total grease and surfactant contents.

A continuous flow autoanalyzer for at-line monitoring of total grease and surfactant contents in alkaline degreasing baths is proposed. For this purpose, a simple, robust, automated configuration has been on-line coupled to an universal response detector, such as the evaporative light scattering one. The proposed autoanalyzer constitutes an advantageous alternative to manual procedures and achieves the determination of both indices in ca.

Taxonicity of anxiety sensitivity: a multi-national analysis.

Taxometric coherent cut kinetic analyses were used to test the latent structure of anxiety sensitivity in samples from North America (Canada and United States of America), France, Mexico, Spain, and The Netherlands (total n = 2741). Anxiety sensitivity was indexed by the 36-item Anxiety Sensitivity Index--Revised (ASI-R; [J. Anxiety Disord.

ATR-FT-IR membrane-based sensor for integrated microliquid-liquid extraction and detection.

A novel straightforward membrane-based sensor, which uses attenuated total reflection Fourier transform infrared (ATR-FT-IR) spectroscopy has been developed. The flow cell designed permits the on-line microliquid-liquid extraction of the target analyte into a organic solvent layer (OSL), which was deposited on the ATR surface using a sequential injection manifold. The aqueous and organic phases are separated via a commercial hydrophobic membrane placed on the PTFE piece of the cell.

Palivizumab in the prophylaxis of respiratory syncytial virus infection.

Respiratory syncytial virus infection continues to be one of the most important health problems in infancy. Active prophylaxis against this infection (i.e.

Autoanalyzer for continuous fractionation and quantitation of the polyphenols content in wines.

A simple continuous flow autoanalyzer for the on-line fractionation of the polyphenols content in wines is proposed. The target compounds are isolated from the matrix by solid-phase extraction on an RP-C18 sorbent column, using selective solvents for the sequential elution of each polyphenol family. Moreover, evaporative light scattering detection (ELSD) is used for the first time for the on-line monitorization of the three polyphenol fractions present in the wine samples.

Present and future applications of carbon nanotubes to analytical science.

This article reviews the impact of carbon nanotubes on analytical science, and the main current and future applications of carbon nanotubes in this field. Given that it is necessary to solubilize carbon nanotubes for many applications, we consider the procedures developed to achieve this. The use of carbon nanotubes in analytical chemistry as a target analyte and as an analytical tool is also discussed.

Direct olive oil authentication: detection of adulteration of olive oil with hazelnut oil by direct coupling of headspace and mass spectrometry, and multivariate regression techniques.

Control of adulteration of olive oil, together with authentication and contamination, is one of the main aspects in the quality control of olive oil. Adulteration with hazelnut oil is one of the most difficult to detect due to the similar composition of hazelnut and olive oils; both virgin olive oil and olive oil are subjected to that kind of adulteration. The main objective of this work was to develop an analytical method able to detect adulteration of virgin olive oils and olive oils with hazelnut oil by means of its analysis by a headspace autosampler directly coupled to a mass spectrometer used as detector (ChemSensor).

Dopamine-dependent iron toxicity in cells derived from rat hypothalamus.

We report a new and specific mechanism for iron-mediated neurotoxicity using RCHT cells, which were derived from rat hypothalamus. RCHT cells exhibit immunofluorescent-positive markers for dopamine beta-hydroxylase and the norepinephrine transporter, NET. In the present study, we observed that iron-induced neurotoxicity in RCHT cells was dependent on (i) formation of an Fe-dopamine complex (100 microM FeCl3:100 microM dopamine); (ii) specific uptake of the Fe-dopamine complex into RCHT cells via NET (79+/-2 pmol 59Fe/mg/min; P<0.

Monoamine transporter inhibitors and norepinephrine reduce dopamine-dependent iron toxicity in cells derived from the substantia nigra.

The role of dopamine in iron uptake into catecholaminergic neurons, and dopamine oxidation to aminochrome and its one-electron reduction in iron-mediated neurotoxicity, was studied in RCSN-3 cells, which express both tyrosine hydroxylase and monoamine transporters. The mean +/- SD uptake of 100 microm 59FeCl3 in RCSN-3 cells was 25 +/- 4 pmol per min per mg, which increased to 28 +/- 8 pmol per min per mg when complexed with dopamine (Fe(III)-dopamine). This uptake was inhibited by 2 microm nomifensine (43%p < 0.

Effect of a novel oil extraction method on avocado (Persea americana Mill) pulp microstructure.

Avocado (Persea americana Mill) is an oil-rich fruit, the pulp containing up to 33% of the oil. It is rich in monounsaturated fatty acids, and has nutritional properties similar to olive oil. However, there is no widespread commercial method for oil recovery from avocado pulp.

Combining headspace gas chromatography with mass spectrometry detection for confirmation of hydrocarbon residues in virgin olive oil following automatic screening.

Hydrocarbon residues can be present in virgin olive oils either naturally or as contaminants. Presence of benzene, toluene, ethylbenzene, xylene isomers and styrene (BTEXS) in virgin olive oil, demanded the establishment of a cut-off level to discriminate oil samples containing these residues at normal levels from those at high levels caused by contamination. By introducing volatile components present in the headspace (HS) of the oil samples (without prior chromatographic separation) into the ionization source of a mass spectrometer, samples were classified as containing normal or high levels of BTEXS (recommendable or non-recommendable forhuman consumption).

Direct automatic screening of soils for polycyclic aromatic hydrocarbons based on microwave-assisted extraction/fluorescence detection and on-line liquid chromatographic confirmation.

An integrated screening-confirmation system for PAHs in soils is presented. The sample screening configuration comprises on-line microwave-assisted extraction of the selected pollutants, followed by continuous preconcentration and sample clean-up on RP-C18. Those samples for which the total concentration is close to or above the threshold limit established (10 microg/g) are subjected to liquid chromatographic separation for confirmation.

Scorpion envenoming in two regions of Colombia: clinical, epidemiological and therapeutic aspects.

To determine clinical and epidemiological features of scorpion stings in two departments of Colombia, a descriptive study was performed in the hospitals of 10 towns from Antioquia (2 256 071 inhabitants) and five from Tolima (630 424 inhabitants). One hundred and twenty-nine cases were admitted during one year, 51 in Antioquia, 78 in Tolima and 41 were children less than 15 years old. Most stings (70.

An ectopic adrenocorticotropic hormone syndrome caused by a sacrococcygeal chordoma: report of a case with a slow progression.

Objective: To report the first case of an ectopic adrenocorticotropic hormone (ACTH) syndrome caused by a sacrococcygeal chordoma.

Methods: We present a case report with clinical, laboratory, and histologic details.

Results: A 76-year-old man was admitted to the hospital because of urinary obstruction.

On the neurotoxicity mechanism of leukoaminochrome o-semiquinone radical derived from dopamine oxidation: mitochondria damage, necrosis, and hydroxyl radical formation.

Leukoaminochrome o-semiquinone radical is generated during one-electron reduction of dopamine oxidation product aminochrome when DT-diaphorase is inhibited. Incubation of 100 microM aminochrome with 100 microM dicoumarol, an inhibitor of DT-diaphorase during 2 h, induces 56% cell death (P < 0.001) with concomitant formation of (i) intracellular hydroperoxides (4.