438 research outputs found
Interferometry of hyper-Rayleigh scattering by inhomogeneous thin films
The use of specific symmetry properties of the optical second-harmonic
generation (the s,s-exclusion rule) has allowed us to observe high-contrast
hyper-Rayleigh interference patterns in a completely diffuse light - an effect
having no analog in case of linear (Rayleigh) scattering.Comment: 8 pages, 3 figure
Multivariate predictive models for the prediction of fatty acids in the EU high added-value "acorn Iberian pig ham" using a miniature near-infrared spectroscopy instrument.
Acorn Iberian ham (Jamón Ibérico de Bellota) is one of the most expensive luxury foodstuffs produced in Europe, with a highly appreciated smell and flavour. Its recognized high-sensorial quality and health properties are mainly due to the traditional outdoor feeding system (Montanera) of Iberian pigs (IP), which provides high standards of animal welfare. Nowadays, one of the frauds affecting this product is the use of “special compound feeds” to simulate the fat composition of the acorns through the inclusion of sources of oleic acid like the ones found in pigs fed outdoors. The high prices paid for a cured leg of Iberian ham –ranging from hundreds to thousands of euros- leads to many opportunities for mislabelling and fraud. Fatty acid content of the adipose tissue could provide evidence of the feeding system. Gas chromatography (GC) is used at industry level for production control purposes. However, it is costly and time-consuming, and it is only applied to batches of animals rather than individual pigs. The main goal of this study was to use spectra belonging to a portable NIRS instrument (MicroNIR Onsite Lite, Viavi Solutions Inc.) for on–site quantitative (fatty acid content) analysis of individual Iberian pork carcasses at the slaughterhouse. Performance of this portable instrument was compared with an at-line NIRS monochromator. PLS models were built and optimized resulting in standard errors of cross validation ranging from 0.83 to 0.84 for palmitic acid, 0.94 to 0.99 for stearic acid, 1.47 to 1.56 for oleic acid and 0.53 to 0.58 for linoleic acid
Armonización del análisis NIRS de grasa de cerdo ibérico: transferencia de calibraciones de ácidos grasos
El objetivo del presente trabajo es mostrar la posibilidad de transferir ecuaciones de
calibración para la determinación de ácidos grasos en grasa de cerdo Ibérico en diferentes
instrumentos NIRS, empleando para ello cápsulas no selladas
Control individualizado de cerdos ibéricos "in vivo" en campo y sobre la canal en matadero mediante tecnología NIRS
El objetivo de este trabajo es la puesta a punto y optimización de la tecnología NIRS para el control del cerdo Ibérico tanto en campo sobre el animal vivo, ya que es una técnica completamente inocua para el animal, como sobre la canal en el matadero, lo cual permitirá consolidar un sistema de trazabilidad basado en sensores no destructivos y rápidos
Validation of a Microwave-Assisted Derivatization Gas Chromatography-Mass Spectrometry Method for the Quantification of 2-Hydroxybutyrate in Human Serum as an Early Marker of Diabetes Mellitus
Circulating levels of 2-hydroxybutyrate (2HB) are highly related to glycemic status in different metabolomic studies. According to recent evidence, 2HB is an early biomarker of the future development of dysglycemia and type 2 diabetes mellitus and may be causally related to the progression of normal subjects to impaired fasting glucose or insulin resistance. In the present study, we developed and validated a simple, specific and sensitive gas chromatography-mass spectrometry (GC-MS) method specifically intended to quantify serum levels of 2HB. Liquid-liquid extraction with ethyl acetate was followed by 2 min of microwave-assisted derivatization. The method presented acceptable accuracy, precision and recovery, and the limit of quantification was 5 µM. Levels of 2HB were found to be stable in serum after three freeze-thaw cycles, and at ambient temperature and at a temperature of 4 °C for up to 24 h. Extracts derivatized under microwave irradiation were stable for up to 96 h. No differences were found in 2HB concentrations measured in serum or plasma EDTA samples. In summary, the method is useful for a rapid, precise and accurate quantification of 2HB in serum samples assessed for the evaluation of dysglycemia and diabetes mellitus
Valentine Allorge (1888-1977). Su contribución a la brioflora española
The VII Bryological Meeting took place on the 5th to the 9th o fApril, 1976 in Mora de Rubielos, its aim being to continue the study of the Iberian System which began in the Sierra de Albarracín. Work done during the Meeting consisted in exploring the sierras of Jabalambre and Gúclar. The result of our gatherings in both these sierras is made known in this article. After a summary study of the vegetation of the area which was the subject of our investigation, the presence of 17 species of Hepaticae and 125 of Mosses is discovered. These resuits form the first contribution for this part of the Iberian System and an important contribution to the knowledge of the Teruel biyodora.La VII Reunión de Briología tuvo lugar los días 5 al 9 de abril de 1976 en Mora de Rubielos, con objeto de continuar el estudio del Sistema Ibérico iniciado con la Sierra de Albarracín. Durante las jornadas de trabajo se exploraron las sierras de Jabalambre y Gúclar. En esta comunicación damos a conocer el resultado de nuestras recolecciones en ambas Sierras. Después de un somero estudio de la vegetación de la zona objeto de nuestro trabajo, se da a conocer la presencia de 17 especies de Hepáticas y 125 de Musgos. Este resultado representa la primera aportación para esta parte del Sistema Ibérico y una notable contribución al conocimiento de la briotlora turolense
Biofortification of UK food crops with selenium
Se is an essential element for animals. In man low dietary Se intakes are associated with health disorders including oxidative stress-related conditions, reduced fertility and immune functions and an increased risk of cancers. Although the reference nutrient intakes for adult females and males in the UK are 60 and 75 μg Se/d respectively, dietary Se intakes in the UK have declined from >60 μg Se/d in the 1970s to 35 μg Se/d in the 1990s, with a concomitant decline in human Se status. This decline in Se intake and status has been attributed primarily to the replacement of milling wheat having high levels of grain Se and grown on high-Se soils in North America with UK-sourced wheat having low levels of grain Se and grown on low-Se soils. An immediate solution to low dietary Se intake and status is to enrich UK-grown food crops using Se fertilisers (agronomic biofortification). Such a strategy has been adopted with success in Finland. It may also be possible to enrich food crops in the longer term by selecting or breeding crop varieties with enhanced Se-accumulation characteristics (genetic biofortification). The present paper will review the potential for biofortification of UK food crops with Se
Predicting Acorn-Grass Weight Gain Index using non-destructive Near Infrared Spectroscopy in order to classify Iberian pig carcasses according to feeding regime
The classification of Iberian pig carcasses into different commercial categories according to feeding regime was evaluated by means of a non-destructive analysis of the subcutaneous adipose tissue using Near Infrared Spectroscopy (NIRS). A quantitative approach was used to predict the Acorn-Grass Weight Gain Index (AGWGI), and a set of criteria was established for commercial classification purposes. A total of 719 animals belonging to various batches, reflecting a wide range of feeding regimes, production systems and years, were analyzed with a view to developing and evaluating quantitative NIRS models. Results for the external validation of these models indicate that NIRS made clear differentiation of batches as a function of three feeding regimes possible with high accuracy (<i>Acorn, Recebo</i> and <i>Feed</i>), on the basis of the mean representative spectra of each batch. Moreover, individual analysis of the animals showed a broad consensus between field inspection information and the classification based on the AGWGI NIRS prediction, especially for extreme categories (<i>Acorn</i> and <i>Feed</i>).<br><br>La clasificación en distintas categorías comerciales según régimen alimenticio de canales de cerdo Ibérico fue evaluada mediante el análisis no destructivo de muestras de tejido adiposo subcutáneo por Espectroscopía del Infrarrojo Cercano (NIRS). Partiendo de una aproximación cuantitativa para predecir el Índice de Reposición en Montanera (IRM) se establecieron una serie de criterios para proceder a su clasificación comercial. Se analizaron un total de 719 animales pertenecientes a diversas partidas, que recogen una amplia variabilidad de muestras de distintos regímenes alimenticios, campañas y sistemas productivos, para el desarrollo y evaluación de los modelos NIRS cuantitativos. Los resultados de validación externa de los modelos indicaron que es posible discriminar con una gran exactitud entre partidas de distintos categorías (<i>Bellota, Recebo</i> y <i>Cebo</i>), en base al espectro medio representativo de cada partida. Además, el análisis individualizado de los animales mostró un amplio consenso entre la información recibida de campo y la clasificación en base a la predicción del parámetro IRM por NIRS, sobre todo para categorías con características extremas (<i>Bellota</i> y <i>Cebo</i>)
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