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Optimization of Matrix Solid-Phase Dispersion method for simultaneous extraction of aflatoxins and OTA in cereals and its application to commercial s…

2010

Abstract A method based on Matrix Solid-Phase Dispersion (MSPD) has been developed for the determination of 5 mycotoxins (ochratoxin A and aflatoxins B and G) in different cereals. Several dispersants, eluents and ratios were tested during the optimization of the process in order to obtain the best results. Finally, samples were blended with C 18 and the mycotoxins were extracted with acetonitrile. Regarding to matrix effects, the results clearly demonstrated the necessity to use a matrix-matched calibration to validate the method. Analyses were performed by liquid chromatography–triple quadrupole-tandem mass spectrometry (LC–QqQ-MS/MS). The recoveries of the extraction process ranged from …

Fast extraction of cannabinoids in marijuana samples by using hard-cap espresso machines

2018

Abstract A simple, quick and low cost procedure was developed for the extraction of Δ9-tetrahydrocannabinol, cannabidiol, and cannabinol from marijuana samples, based on the use of a hard-cap espresso extraction with 2-propanol. After extraction, cannabinoids were directly determined after appropriate dilution by gas-chromatography-mass spectrometry, reaching a limit of detection from 0.03 to 0.05 mg g−1. Extraction efficiency was evaluated by the comparison of results obtained for seized samples by the proposed method and a reference methodology based on ultrasound-assisted extraction. Moreover, ion mobility was proposed for the rapid and sensitive determination of Δ9-tetrahydrocannabinol …

Le determinanti della produttività: fattori di offerta e fattori di domanda

2014

In vivo study of different methods for diagnosing pit and fissure caries

2015

Background In recent years the early detection of such caries has gained importance, since it may avoid unnecessary dental tissue damage and allow minimally invasive dental treatment. A study is made of 5 systems for diagnosing caries: traditional visual and tactile methods, DIAGNOdent, VistaProof and CarieScan. Material and Methods A prospective study was made in the Department of Stomatology, Dental Pathology and Therapeutics Teaching unit of the University of Valencia (Valencia, Spain), involving the analysis of 32 teeth (molars or premolars of both arches scheduled for filling or for use as posts in dental bridges) in 28 patients. The following caries diagnostic methods were applied: vi…

The dialectics of spatial performances: The interplay of tensions in activity-based organizing

2019

Navigating organizational workspace is often plagued with tensions that emerge from the interplay of intended designs with organizational activities and lived experiences. These tensions are evident in research findings, such as inconsistencies in the ways that employees react to new workplace designs. They call on scholars to rethink organizational space, not as a concrete, static, or ready-made ‘thing’, but as a set of ongoing performances that enact particular practices, clashes among opposites, and organizational tensions. Based on research in a Nordic company, this study reveals how tensions and responses to them in an activity-based office generate creative alternatives that enhance …

Las representaciones del saber académico: Aportaciones desde la Geografía Escolar

2019

When we talk with basic education´s teachers there is an impression in the case of learning Social Sciences, and Geography in particular that these sciences are not useful for the explanation of socio-environmental and daily problems. In this research, improvement proposals are sought so that students are motivated to learn about these problems. Based on two case studies such as flood risks (and their relationship with climate change) and the problems of the rural areas, the possibilities of combining motivation for learning close to personal emotions and with their own rigor have been explored of the conceptual explanation. To validate these results, quantitative and qualitative research t…

Three-dimensional behavior of apodized nontelecentric focusing systems.

2002

The scalar field in the focal volume of nontelecentric apodized focusing systems cannot be accurately described by the Debye integral representation. By use of the Fresnel–Kirchhoff diffraction formula it is found that, if the aperture stop is axially displaced, the focal-volume structure is tuned. We analyze the influence of the apodizing function and find that, whereas axially superresolving pupil filters are highly sensitive to the focal-volume reshaping effect, axially apodizing filters are more inclined to the focal-shift effect.

La ratio interdigital D2:D4 y su relación con otros indicadores de androgenización en progenitores de personas con trastornos del espectro autista

2013

The 2D:4D ratio is the quotient between the index and ring finger lengths and is a non-direct indicator of androgenisation. If prenatal testosterone levels in the amniotic fluid are high then the probability increases of developing lower ratio values. It has been suggested that people with autism spectrum disorders (ASD) and their parents may have highly androgenised brains, and for this reason the 2D:4D ratio is used as a marker of such idiosyncrasies. This study aims to analyse if parents of people with ASD differ from the general population in several parameters of androgenisation related to the 2D:4D ratio. The sample was composed of 43 parents of offspring with ASD and 42 controls who …

Assessing an overland flow resistance approach under equilibrium sediment transport conditions

2021

Abstract In this study, for the first time, a theoretically deduced flow resistance equation was tested for an overland flow under equilibrium sediment transport conditions using available experimental data by Liu et al. for five Chinese soils. Initially the relationship among the velocity profile parameter Γ, the channel slope, the flow Reynolds number, the Froude number and the sediment concentration was calibrated using 90 measurements of the available database (Loessial, Cinnamon and Black soil) and tested by other 60 measurements (Red and Purple soil). The results proved that the Darcy–Weisbach friction factor can be accurately estimated by the proposed theoretical approach, with error…

Testing a theoretically-based overland flow resistance law by Emmett’s database

2021

Abstract The main aim of this paper was to test a recently theoretically deduced flow resistance equation, based on a power-velocity profile, using a wide database of available measurements carried out in laboratory and field experimental runs with overland flow under simulated rainfall. In comparison with previous calibrations and validations of this theoretically deduced flow resistance equation, the used database by Emmett is characterized by a wide range of rainfall intensities (from 79.2 to 303.5 mm h−1 for laboratory runs and from 178.3 to 215.9 mm h−1 for field investigations) and bed slopes (from 0.33 to 17% for laboratory runs and from 2.9 to 33.2% for field investigations). For th…