Search results for "Methods"

A study on the essential oil of Ferulago campestris : How much does extraction method influence the oil composition?

2011

The essential oil of different parts of Ferulago campestris (Bess.) collected in Sicily has been extracted by microwave-assisted hydrodistillation (MAHD) and by classic hydrodistillation (HD). A comparative qualitative-quantitative study on the composition of the oils was carried out. A total of 100 compounds were identified in the oils obtained by MAHD, whereas 88 compounds characterized the HD oils. The most prominent components were, in all different parts of F. campestris and in both extraction methods, 2,4,5-trimethylbenzaldehyde and 2,4,6-trimethylbenzaldehyde isomers; the latter was not previously found. The attempt to evaluate where the oil components are located in all parts of the…

Application of a new glass capillary chromatographic technique in the analysis of phenoxyacetic acid herbicides.

1976

Voltammetric determination of dipeptidyl aminopeptidases I and IV

1992

Dipeptidyl aminopeptidases I and IV have recently found wide practical application (polypeptide sequencing, clinical diagnostics) so it is necessary to extend present methods and work out new ones for determination of their activity. A new, voltammetric method for determination of peptidase activity is proposed, which allows optimization of the determination conditions according to the activity to be measured. The method has some advantages over the spectrophotometric methods, such as applicability to opaque solutions and higher sensitivity.

Use of protein profiles established by CZE to predict the cultivar of olive leaves and pulps

2014

Intact protein profiles established by CZE have been used to predict the cultivar of olive leaves and pulps. For this purpose, proteins were extracted using a mild enzyme-assisted extraction method, which provided higher protein recoveries and a lower environmental impact than other previously described methods. These extracts were subjected to CZE determination under basic conditions using a BGE composed of 50 mM phosphate, 50 mM tetraborate and 0.1% PVA at pH 9. Nine and 14 common peaks, for leaf and pulp samples, respectively, were identified in the nine cultivars studied in this work. In addition, and using linear discriminant analysis of the CZE data, olive leaf and pulp samples belong…

Retrospective screening of pesticide metabolites in ambient air using liquid chromatography coupled to high-resolution mass spectrometry

2015

A new methodology for the retrospective screening of pesticide metabolites in ambient air was developed, using liquid chromatography coupled to Orbitrap high-resolution mass spectrometry (UHPLC-HRMS), including two systematic workflows (i) post-run target screening (suspect screening) and (ii) non-target screening. An accurate-mass database was built and used for the post-run screening analysis. The database contained 240 pesticide metabolites found in different matrixes such as air, soil, water, plants, animals and humans. For non-target analysis, a "fragmentation-degradation" relationship strategy was selected. The proposed methodology was applied to 31 air samples (PM10) collected in the…

Classification of Extra Virgin Olive Oils Produced at La Comunitat Valenciana According to Their Genetic Variety Using Sterol Profiles Established by…

2009

A method to classify extra virgin olive oils (EVOOs) according to their genetic variety using sterol profiles obtained by high-performance liquid chromatography (HPLC) with mass spectrometry (MS) detection has been developed. Sterol extracts were chromatographed on a dC18 Atlantis column (100x3 mm, 3 microm) with a gradient of acetonitrile/water (0.01% acetic acid) at a flow rate of 1.0 mL min(-1) and positive-ion mode MS detection. Using linear discriminant analysis of the HPLC-MS data (extracted ion chromatograms), EVOO samples belonging to six genetic varieties cultivated at La Comunitat Valenciana, Spain (Arbequina, Borriolenca, Canetera, Farga, Picual, and Serrana), were correctly clas…

Staining mitochondria in Saccharomyces cerevisiae.

1969

After testing various procedures (amidoblack 10B, acid fuchsin-methyl blue, Luxol fast blue MBS-phloxine, toluidine blue O, Jams green B and pinacyanol), three stains can be recommended for staining both types of mitochondria (globose and threadlike) in the cells of Saccharomyces cerevisiae: (1) 0.1% solution of amidoblack 10B in citrate buffer (pH 3.0) for 10 min; (2) 0.01% solution of toluidine blue O in phosphate buffer (pH 6.0) for 30 min; (3) 0.01% solution of Janus green B in distilled water (pH 5.6) for 30 min. The latter stain is most specific because its staining reaction depends upon the action of the mitochondrial enzyme cytochrome c oxidase. Yet, low concentrations and short inc…

Antennas for the detection of radio emission pulses from cosmic-ray induced air showers at the Pierre Auger Observatory.

2012

The Pierre Auger Observatory is exploring the potential of the radio detection technique to study extensive air showers induced by ultra-high energy cosmic rays. The Auger Engineering Radio Array (AERA) addresses both technological and scientific aspects of the radio technique. A first phase of AERA has been operating since September 2010 with detector stations observing radio signals at frequencies between 30 and 80 MHz. In this paper we present comparative studies to identify and optimize the antenna design for the final configuration of AERA consisting of 160 individual radio detector stations. The transient nature of the air shower signal requires a detailed description of the antenna s…

Measurement of the radiation energy in the radio signal of extensive air showers as a universal estimator of cosmic-ray energy

2016

We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8±0.7(stat)±6.7(syst) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principles calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the d…

Searches for Large-Scale Anisotropy in the Arrival Directions of Cosmic Rays Detected above Energy of $10^{19}$ eV at the Pierre Auger Observatory an…

2014

Spherical harmonic moments are well-suited for capturing anisotropy at any scale in the flux of cosmic rays. An unambiguous measurement of the full set of spherical harmonic coefficients requires full-sky coverage. This can be achieved by combining data from observatories located in both the northern and southern hemispheres. To this end, a joint analysis using data recorded at the Telescope Array and the Pierre Auger Observatory above 1019 eV is presented in this work. The resulting multipolar expansion of the flux of cosmic rays allows us to perform a series of anisotropy searches, and in particular to report on the angular power spectrum of cosmic rays above 1019 eV. No significant devia…