760 research outputs found

    Mercury and selenium binding biomolecules in terrestrial mammals (Cervus elaphus and Sus scrofa) from a mercury exposed area

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    Acknowledgements The authors are grateful to Junta de Comunidades de Castilla-La Mancha (PCC-05-004-2, PAI06-0094, PCI-08-0096, PEII09-0032-5329) and the Ministerio de Economía y Competitividad (CTQ2013-48411-P) for financial support. M.J. Patiño Ropero acknowledges the Junta de Comunidades de Castilla-La Mancha for her PhD. fellowship.Peer reviewedPostprin

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    Methane emission by alpaca and sheep fed on lucerne hay or grazed on pastures of perennial ryegrass/white clover or birdsfoot trefoil

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    Based on the knowledge that alpaca (Lama pacos) have a lower fractional outflow rate of feed particles (particulate FOR) from their forestomach than sheep (San Martin 1987), the current study measured methane (CH4) production and other digestion parameters in these species in three successive experiments (1, 2 and 3): Experiment 1, lucerne hay fed indoors; Experiment 2, grazed on perennial ryegrass/white clover pasture (PRG/WC); and Experiment 3, grazed on birdsfoot trefoil (Lotus corniculatits) pasture (Lotus). Six male alpaca and six castrated Romney sheep were simultaneously and successively fed on the forages either ad libitium or at generous herbage allowances (grazing). CH4 production (g/day) (using the sulphur hexafluoride tracer technique), voluntary feed intake (VFI), diet quality, and protozoa counts and volatile fatty acid concentrations in samples of forestomach contents were determined. In addition, feed digestibility, energy and nitrogen (N) balances and microbial N supply from the forestomach (using purine derivatives excretion) were measured in Experiment 1. Diets selected by alpaca were of lower quality than those selected by sheep, and the voluntary gross energy intakes (GEI, MJ) per kg of liveweight(0.75) were consistently lower (P0.05) in their CH4 yields (% GEI) when fed on lucerne hay (5.1 v. 4.7), but alpaca had a higher CH4 yield when fed on PRG/WC (9.4 v. 7.5, P0.05) in diet N partition or microbial N yield, but alpaca had higher (P<0.05) neutral detergent fibre digestibility (0.478 v. 0.461) and lower (P<0.01) urinary energy losses (5.2 v. 5.8 % GEI) than sheep. It is suggested that differences between these species in forestomach particulate FOR might have been the underlying physiological mechanism responsible for the differences in CH4 yield, although the between-species differences in VFI and diet quality also had a major effect on it

    Pasado, presente y futuro del búfalo en Argentina

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    El búfalo comenzó a ser introducido al país a comienzo el siglo XX, mediante la importación razas Mediterránea, Murrah y Jafarabadi. En la actualidad la población bubalina alcanzó las de 87.711 cabezas y se encuentran distribuidas en 20 de las 23 provincias que componen el territorio nacional. El 80 % de la población de búfalos se encuentran en el nordeste argentino. Siendo las provincias de Formosa y Corrientes las que cuentan con la mayores poblaciones bubalinas. Existen en el país 8 millones de hectáreas aptas para soportar una carga de 4 millones de búfalos.The buffalo began to be introduced to the country in the early twentieth century, by importing Mediterranean, Murrah and Jafarabadi breeds. Today buffalo population reached 87.711 heads, which are distributed in 20 out of the 23 provinces that conforms the country. The 80% of the population of buffaloes is found in northeastern region, being the provinces of Formosa and Corrientes those with the largest buffalo population. The country has 8 million hectares suitable to withstand a load of 4 million buffaloes.Fil: Crudeli, G. A.. Universidad Nacional del Nordeste. Facultad de Cs.veterinarias; ArgentinaFil: Patiño, E. M.. Universidad Nacional del Nordeste. Facultad de Cs.veterinarias; ArgentinaFil: Maldonado Vargas, P.. Universidad Nacional del Nordeste. Facultad de Cs.veterinarias; ArgentinaFil: Konrad, José Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Nordeste. Facultad de Cs.veterinarias; Argentin

    Obtention of Antimicrobial Fibers Type Core/Shell PLA/PVOH-LAE by Coaxial Electrospinning

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    Coaxial electrospinning (EC) is a technology that allows the encapsulation of active compounds, as ethyl lauroyl arginate (LAE), in shell/core structures, in order to develop new antimicrobial food packaging materials with slowdown of active compound´s release with the purpose of extending food shelf life. For this reason, the objective of this study consisted in developing antimicrobial fibers shell/core type by EC. Two polymers with different hydrophilic character as poly (lactic acid) (PLA) to the shell and poly (vinyl alcohol) (PVOH) and LAE to the core were used to obtain PLA/PVOH-LAE fibers, and slowdown the release of antimicrobial compound. The morphology of fibers was evaluated by optical microscopy and the thermal properties through thermogravimetric analyses (TGA). Release studies were carried out in fatty (ETOH 95%) food simulant and was compared with the minimum inhibitory concentration (MIC) values of LAE against Listeria innnocua. The optical micrographs evidenced the obtention of shell/core structure with an average diameter of 0,6 µm approximately, and the TGA analyses demonstrated the thermal protection of LAE by shell of fibers. Released LAE reached the equilibrium state in ETOH 95% during the first 3 hours, maintaining a higher concentration than MIC value obtained in L. innnocua (10 ppm). The results demonstrate that new packaging materials with antimicrobial activity as PLA/PVOH-LAE polymeric fibers with shell/core structure can be obtained through coaxial electrospinning technique. Keywords: coaxial electrospinning, ethyl lauroyl arginate, fibers, shell/core, food packaging. Resumen El electrohilado coaxial (EC) es una tecnología que permite encapsular compuestos activos como el etil lauroil arginato (LAE) en estructuras tipo pared/núcleo con la finalidad de desarrollar nuevos materiales antimicrobianos para el envasado de alimentos que ralenticen la liberación del compuesto y extiendan la vida útil del alimento. Por tal razón, el objetivo de este estudio consistió en desarrollar fibras antimicrobianas tipo pared/núcleo mediante EC. Dos polímeros con distinto carácter hidrofílico como el poli (ácido láctico) (PLA) para la pared y poli (alcohol vinílico) (PVOH) y LAE para el núcleo se utilizaron para obtener las fibras PLA/PVOH-LAE, y ralentizar la liberación del compuesto antimicrobiano. La morfología de las fibras se evaluó mediante microscopía óptica y sus propiedades térmicas mediante análisis termogravimétricos (TGA). Se realizaron estudios de liberación del LAE en un simulante de alimentos graso (ETOH 95%), y se comparó con la concentración mínima inhibitoria (MIC) hacia una bacteria Gram positiva Listeria innnocua. Las micrografías ópticas evidenciaron la obtención de la estructura pared/núcleo con un diámetro promedio de 0,6 µm aproximadamente, y el análisis TGA demostró la protección térmica del LAE por la pared de las fibras. El LAE liberado alcanzó el estado de equilibrio en ETOH 95% durante las 3 hr iniciales, manteniendo una concentración superior a la MIC obtenida para L. innnocua (10 ppm). Los resultados demuestran que nuevos materiales de envase con actividad antimicrobiana como fibras poliméricas PLA/PVOH-LAE con estructura pared/núcleo pueden ser obtenidos mediante la técnica de electrohilado coaxial. Palabras clave: electrohilado coaxial, etil lauroil arginato, fibras, pared/núcleo, envase de alimentos

    Obtention of Antimicrobial Fibers Type Core/Shell Pla/Pvoh-Lae By Coaxial Electrospinning

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    Coaxial electrospinning (EC) is a technology that allows the encapsulation of active compounds, such as ethyl lauroyl arginate (LAE), in shell/core structures, in order to develop new antimicrobial materials for food packaging that slow down the release of active compounds and extend the food’s shelf life. For this reason, the objective of this study was to develop antimicrobial fibers shell/core type by EC. Two polymers with different hydrophilic character, polylactic acid (PLA) for the shell and polyvinyl alcohol (PVOH) and LAE for the core, were used to obtain PLA/PVOH-LAE fibers and slow the release of the antimicrobial compound. The morphology of fibers was evaluated by optical microscopy and their thermal properties through thermogravimetric analyses (TGA). LAE release studies were carried out in a fatty food simulant (ETOH 95%), and was compared with the minimum inhibitory concentration (MIC) values of LAE against a gram-positive bacteria, Listeria innnocua. The optical micrographs showed the obtaining of the shell/core structure with an average diameter of approximately 0.6 µm, and the TGA analyses demonstrated the thermal protection of LAE by the shell of the fibers. Released LAE reached the equilibrium state in ETOH 95% during the first 3 hours, maintaining a higher concentration than the MIC value obtained in L. innnocua (10 ppm). The results demonstrate that new packaging materials with antimicrobial activity such as PLA/PVOH-LAE polymeric fibers with a shell/core structure can be obtained through the coaxial electrospinning technique. Keywords: coaxial electrospinning, ethyl lauroyl arginate, fibers, shell/core, food packaging. Resumen El electrohilado coaxial (EC) es una tecnología que permite encapsular compuestos activos como el etil lauroil arginato (LAE) en estructuras tipo pared/núcleo con la finalidad de desarrollar nuevos materiales antimicrobianos para el envasado de alimentos que ralenticen la liberación del compuesto y extiendan la vida útil del alimento. Por tal razón, el objetivo de este estudio consistió en desarrollar fibras antimicrobianas tipo pared/núcleo mediante EC. Dos polímeros con distinto carácter hidrofílico como el poli (ácido láctico) (PLA) para la pared y poli (alcohol vinílico) (PVOH) y LAE para el núcleo se utilizaron para obtener las fibras PLA/PVOH-LAE, y ralentizar la liberación del compuesto antimicrobiano. La morfología de las fibras se evaluó mediante microscopía óptica y sus propiedades térmicas mediante análisis termogravimétricos (TGA). Se realizaron estudios de liberación del LAE en un simulante de alimentos graso (ETOH 95%), y se comparó con la concentración mínima inhibitoria (MIC) hacia una bacteria Gram positiva Listeria innnocua. Las micrografías ópticas evidenciaron la obtención de la estructura pared/núcleo con un diámetro promedio de 0,6 µm aproximadamente, y el análisis TGA demostró la protección térmica del LAE por la pared de las fibras. El LAE liberado alcanzó el estado de equilibrio en ETOH 95% durante las 3 hr iniciales, manteniendo una concentración superior a la MIC obtenida para L. innnocua (10 ppm). Los resultados demuestran que nuevos materiales de envase con actividad antimicrobiana como fibras poliméricas PLA/PVOH-LAE con estructura pared/núcleo pueden ser obtenidos mediante la técnica de electrohilado coaxial. Palabras clave: electrohilado coaxial, etil lauroil arginato, fibras, pared/núcleo, envase de alimentos

    Recubrimientos no cristalinos en rocas graníticas de Galicia: propiedades e hipótesis sobre su origen

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    [Resumen] La caracterización de nuevos recubrimientos de bajo grado de orden en macizos graníticos de Galicia y el estudio de algunas propiedades de éstos y de otros previamente descritos, confirma la hipótesis de la existencia de una serie continua de materiales cuya composición varía entre la de fosfatos de aluminio (variscita, evansita),aluminosilicatos poco ordenados (alofanos geológicos, haloisita) e hidróxidos de aluminio (gel de alúmina hidratado,gibbsita). Del análisis de sus características y de algunas de sus propiedades como superficie específica, reacción frente a los ani ones fluoruro y fosfato, solubilidad en diferentes extractantes, punto cero de carga,etc., se establecen y discuten diversas hipótesis sobre su origen. Se discuten además relaciones de equilibrio o en el sistema Si02-A1203-P20~,confrontándolas con los datos de aguas de escorrentla y solución del suelo.[Abstract] The characterization of low order coatings that appear on granitic rocks of Galicia and the study of some of their properties confirm the existence of a continuous series between Al-phosphates (variscite,evan site),aluminium silicates (allophane,halloysite) ano Al-hydroxides (criptogibbsite,gibbsite).Several hypothe sis about their origin are discussed on the basis OT properties like specific surface, reaction with fluoride and phosphate, pze, solubility in different extracttants, etc . Finally, the theoretical equilibrium relations in the system A1203-Si02-P205 are confronted with the composition of dralnage waters and soil solutio

    Refining the associations of the Fermi Large Area Telescope Source Catalogs

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    The Fermi-Large Area Telescope (LAT) First Source Catalog (1FGL) was released in February 2010 and the Fermi-LAT 2-Year Source Catalog (2FGL) appeared in April 2012, based on data from 24 months of operation. Since their releases, many follow up observations of unidentified gamma-ray sources (UGSs) were performed and new procedures to associate gamma-ray sources with potential counterparts at other wavelengths were developed. Here we review and characterize all the associations as published in the 1FGL and 2FGL catalog on the basis of multifrequency archival observations. In particular we located 177 spectra for the low-energy counterparts that were not listed in the previous Fermi catalogs, and in addition we present new spectroscopic observations of 8 gamma-ray blazar candidates. Based on our investigations, we introduce a new counterpart category of "candidate associations" and propose a refined classification for the candidate low-energy counterparts of the Fermi sources. We compare the 1FGL-assigned counterparts with those listed in the 2FGL to determine which unassociated sources became associated in later releases of the Fermi catalogs. We also search for potential counterparts to all the remaining unassociated Fermi sources. Finally, we prepare a refined and merged list of all the associations of the 1FGL plus 2FGL catalogs that includes 2219 unique Fermi objects. This is the most comprehensive and systematic study of all the associations collected for the gamma-ray sources available to date. We conclude that 80% of the Fermi sources have at least one known plausible gamma-ray emitter within their positional uncertainty regions.Comment: 26 pages, 24 figures, 7 tables, ApJS accepted for publication (pre-proof version uploaded
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