Segregation-induced grain boundary electrical potential in ionic oxide materials: A first principles model

A first principles continuum analytical model for cationic segregation to the grain boundaries in complex ceramic oxides is presented. The model permits one to determine the electric charge density and the segregation-induced electric potential profiles through the grain and can be extrapolated to the range of nanostructured grain sizes. The theoretical predictions are compared with existing data for yttria-stabilized tetragonal zirconia polycrystals. The implications for physical properties (mainly high temperature plasticity and hardening behaviour) are then discussed.Gobierno de España MAT2009-14351-C02-01, MAT2009-14351-C02-0

Systematic Study of the Content of Phytochemicals in Fresh and Fresh-Cut Vegetables

Vegetables and fruits have beneficial properties for human health, because of the presence of phytochemicals, but their concentration can fluctuate throughout the year. A systematic study of the phytochemical content in tomato, eggplant, carrot, broccoli and grape (fresh and fresh-cut) has been performed at different seasons, using liquid chromatography coupled to triple quadrupole mass spectrometry. It was observed that phenolic acids (the predominant group in carrot, eggplant and tomato) were found at higher concentrations in fresh carrot than in fresh-cut carrot. However, in the case of eggplant, they were detected at a higher content in fresh-cut than in fresh samples. Regarding tomato, the differences in the content of phenolic acids between fresh and fresh-cut were lower than in other matrices, except in winter sampling, where this family was detected at the highest concentration in fresh tomato. In grape, the flavonols content (predominant group) was higher in fresh grape than in fresh-cut during all samplings. The content of glucosinolates was lower in fresh-cut broccoli than in fresh samples in winter and spring sampling, although this trend changes in summer and autumn. In summary, phytochemical concentration did show significant differences during one-year monitoring, and the families of phytochemicals presented different behaviors depending on the matrix studied

ESTUDIO DE LA INFLUENCIA DE pH Y TEMPERATURA EN LA RACEMIZACIÓN DE (-)-HIOSCIAMINA A (+)-HIOSCIAMINA EN SEMILLAS DE ESTRAMONIO

El estramonio es una planta de la familia de las Solenaceaes, del género Daturae, que crece como maleza junto a campos de cultivo. Debido a su toxicidad y sus efectos sobre la alimentación y la seguridad de los piensos animales y alimentos para los humanos, la determinación de sustancias tóxicas en estas plantas está ganado interés. Los principales componentes tóxicos son la escopolamina y la atropina (mezcla racémica de (+) y (-)-hiosciamina). Aunque la atropina sea una mezcla racémica, solo el enantiómero encontrado naturalmente, la (-)-hiosciamina, tiene actividad farmacológica, siendo un potente anticolinérgico [1,2]. La racemización ocurre en el proceso de extracción de la (-)-hiosciamina, con temperaturas elevadas y prolongadas y pH básico, siendo muy escasos los estudios realizados en este sentido [3]. Así mismo resulta de interés conocer las condiciones en las que se produce la racemización de un compuesto en otro, ya que las mismas son también de aplicación en procesos del cocinado (cocción u horneado) de alimentos que contengan pequeñas cantidades de semillas de plantas de la familia de las Solenaceaes. En la presente comunicación se realiza un estudio de la influencia del pH y la temperatura en dicho proceso. A tal fin se realizaron experiencias a valores de pH de 3, 5, 7 y 9 y temperaturas de 30, 50 y 80ºC. Así mismo se estudió la influencia del mantenimiento de algunas condiciones (pH 5 y 9 a 80ºC) en el proceso de conversión de racemización. Para estudiar estos factores se hace uso de un método basado en cromatografía de líquidos de alto rendimiento acoplada a espectrometría de masas en tándem (HPLCMS/ MS), empleando una columna quiral, Chiralpak-AY3. La separación se realiza en modo isocrático usando etanol al 0,1% dietanolamina como fase móvil, en un tiempo de 10 minutos. La extracción de la hiosciamina de las semillas de estramonio se realiza mediante el método QuEChERS

Enantiomeric separation of (-) and (+)- hyosciamine by high performance liquid chromatography-tandem mass spectrometry

Interest in natural toxins produced by fungi or plants has grown in recent years due to its toxicity and its impact on feeding and animal feed and human food safety. Among these toxins, alkaloids and more specifically tropane alkaloids, are very significant and they are characterized by presenting anticholinergic activity. Tropane alkaloids are synthesized by the plants from Solanaceae family and in smaller quantities from plants from other families. This family of compounds involves more than 200 compounds, although the compounds most studied are scopolamine, atropine and (-)-hyoscyamine [1]. In the case of atropine, which is a racemic mixture of (-) and (+)-hyoscyamine, it is well known that (-)-hyoscyamine exhibit stronger anticholinergic effects than the (+)-hyoscyamine. Moreover, racemization occurs during the treatment process of the raw material and cooking procedures due to pH and temperature modifications, since only the (-)-hyoscyamine is naturally formed. For this reason, according to the EFSA interest in 2013 [1] it is necessary to develop methods which allows the separation of these two chiral enantiomers to elucidate the conditions that favor the transformation between both enantiomers, because there are not many studies that evaluate these processes. Therefore the aim of this study is the optimization of the enantioselective separation of (-) and (+)-hyoscyamine with a Chiralpak-AY3 (150x4.6 mm, 3 μm) analytical column in combination with high performance liquid chromatography (HPLC)-coupled to tandem mass spectrometry (MS/MS) has been used. The developed method allowed the separation of the two target compounds in 10 min, using ethanol 0.1% diethanolamine as mobile phase. In addition, the influence of differents parameters, such as pH apparent or temperature, in the signal of the (-) and (+)-hyoscyamine was studied. Finally the method was applied to the determination of the target compounds in buckwheat samples. Performance characteristics, such as trueness (in terms of recovery), precision, linearity, detection limits (LODs) and quantification limits (LOQs) were studied. Suitable performance characteristics were obtained for a reliable determination of both enantiomers in the selected samples

Electrical properties of reduced 3YTZP ceramics consolidated by spark plasma sintering

3 mol% Yttria doped zirconia ceramics were consolidated by spark plasma sintering (SPS) at two sintering temperatures with the aim of achieving two different reduction levels. Microstructural characterization of the ceramics was performed by scanning electron microscopy (SEM). Electrical properties were investigated by means of impedance spectroscopy from room temperature up to 500 °C. The two ceramics presented a remarkably different electrical behavior. The effect of the extra electrons introduced by reduction during SPS on both the bulk and the grain boundary conductivity was analyzed and discussed.España Mineco MAT2009-11078 MAT2012-34217Junta de Andalucia P12-FQM-107

Offline Solid-Phase Extraction and Separation of Mineral Oil Saturated Hydrocarbons and Mineral Oil Aromatic Hydrocarbons in Edible Oils, and Analysis via GC with a Flame Ionization Detector

A method was developed for the determination of mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH) in edible oils, achieving similar limits of quantification than those obtained by online extraction methodologies, i.e., 0.5 mg/kg. The isolation of MOSH and MOAH was performed in a silver nitrated silica gel stationary phase prior to their analysis by gas chromatography–flame ionization detector (GC-FID). To improve the sensitivity, the simulated on-column injection method, using a suitable liner, was optimized. The method was validated at 0.5, 10.0 and 17.9 mg/kg, and recoveries ranged from 80 to 110%. Intra and inter-day precision were evaluated at the same levels, and relative standard deviation (RSD) was lower than 20%. The method was applied to a total of 27 samples of different types of oil previously analyzed in an accredited laboratory, detecting MOSH up to 79.2 mg/kg and MOAH up to 22.4 mg/kg

Compuesto deuterados de flonicamida, procedimiento de preparación y uso de los mismos

ES2644163 A1 (27.11.2017) P201600466 (27.05.2016)Compuestos deuterados de flonicamida, procedimiento de preparación y uso de los mismos. La invención se refiere a un compuesto deuterado de flonicamida, de fórmula (I) en la que R1 es un grupo seleccionado entre -CH2-CN y -CH2-COOH; y R2 es H, y en la que al menos un átomo de hidrógeno en R1 o en R2 está sustituido por deuterio; a su procedimiento de obtención y a su uso como patrón para la detección y cuantificación de flonicamida y derivados mediante técnicas cromatográficas acopladas a espectrometría de masas.UNIVERSIDAD DE ALMERÍ

An Interpretation of Article 24 of the Constitution of Japan: Reconsidering the Principle of \u27\u27Gender Equality\u27\u27 from the Perspective of \u27\u27the Dilemma of Difference\u27\u27

This paper presents a novel methodology to calculate cation diffusion coefficients and activation energies in cubic Y2O3–ZrO2 by Molecular Dynamics. The calculation is based upon modulating the interaction potential to promote cation mobility within the lattice. The technique was calibrated by measuring static properties and oxygen self-diffusion characteristics, and then applied to cation diffusion. The respective activation energies and diffusion coefficients agree well with experimental findings. Preliminary results about grain boundary cation diffusion are presented for the first time as a proof of the potentiality of the procedureMinisterio de Ciencia e Innovación MAT2009-14351-C02-01, MAT2009-14351-C02-02Agencia Española de Cooperación Internacional y Desarrollo 53687