174 research outputs found
Time course of early metabolic changes following diffuse traumatic brain injury in rats as detected by 1H NMR spectroscopy
Experimental models of traumatic brain injury (TBI) provide a useful tool for understanding the cerebral metabolic changes induced by this pathological condition. Here, we report on the time course of changes in cerebral metabolites after TBI and its correlation with early brain morphological changes using a combination of high-resolution proton magnetic resonance spectroscopy ( 1H MRS) and magnetic resonance imaging (MRI). Adult male Sprague-Dawley rats were subjected to closed head impact and examined by MRI at 1, 9, 24, 48, and and 72 h after the injury. Extracts from funnel frozen rat brains were then obtained and analyzed quantitatively by high-resolution 1H MRS. Finally, statistical multivariate analysis was carried out to identify the combination of cerebral metabolites that best described the time evolution of diffuse TBI. The temporal changes observed in the concentration of cerebral metabolites followed three different patterns. The first pattern included taurine, threonine, and glycine, with concentrations peaking 24 h after the injury. The second pattern included glutamate, GABA, and alanine, with concentrations remaining elevated between 24 and 48 h post-injury. The third one involved creatine-phosphocreatine, N-acetylaspartate, and myo-inositol, with concentrations peaking 48 h after the injury. A multivariate stepwise discriminant analysis revealed that the combination of the organic osmolytes taurine and myo-inositol allowed optimal discrimination among the different time groups. Our findings suggest that the profile of some specific brain molecules that play a role as organic osmolytes can be used to follow-up the progression of the early diffuse brain edema response induced by TBI. © Mary Ann Liebert, Inc.This work was partly supported by Spanish Ministry of Education and Science (grants SAF 2001-224 and SAF 2004-03197 to J.M.R. and S.C.) and by Spanish Ministry of Health (grants FISss C03/08, C03/10, and G03/155 to J.M.R. and S.C.).Peer Reviewe
NiGa Unsupported Catalyst for CO2 Hydrogenation at Atmospheric Pressure. Tentative Reaction Pathways
The hydrogenation of CO2 is presented as a catalytic strategy for CO2 utilization and an approach to the development of sustainable processes to obtain products with high added value, such as CO, CH4, and CH3OH. An unsupported NixGay model catalyst with high surface area was synthesized by an ultrasonic-assisted coprecipitation method. The in situ H2-treatment and the activation temperature (600, 700, and 800 °C) are key in the phases present in the catalyst and, therefore, in the reactivity in the CO2 hydrogenation reaction at atmospheric pressure. Operating conditions have been selected that maximize the selectivity to be able to correlate phases, surface, and reactivity.
Independently of the H2/CO2 feed ratio, after treatment in hydrogen at 600 °C, CO selectivity values are higher than 97%, via a
reverse water gas shift reaction, with Ni13Ga9 and Ni metallic being the main phases detected. The H2-treatment at 700 °C increases the proportion of Ni0 and Ni13Ga9 phases, and even with the use of a H2/CO2 feeding ratio of 3, methanation is the only reaction that occurs. At 800 °C, Ni5Ga3 is the main phase detected, and methanol is formed at 150 °C, through the intervention of a necessary formate species; when the reaction temperature is higher than 400 °C, the rWGS is the only observable reaction, with complete CO formation.Funding for open access charge: Universidad de Málaga / CBU
Magnetic Resonance Imaging of Gliomas
Open Access.This work was supported in part by grants CTQ2010-20960-C02-02 to P.L.L. and grant SAF2008-01327 to S.C. A.M.M. held an Erasmus Fellowship from Coimbra University and E.C.C. a predoctoral CSIC contract.Peer Reviewe
Isotopic study of the influence of oxygen interaction and surface species over different catalysts on the soot removal mechanism
In order to improve the catalytic formulations for soot removal in after-treatment emission control technologies for gasoline and diesel engine vehicle, an isotopic study was approached using transitory labeled oxygen response method over model catalysts that allows the unraveling of soot oxidation mechanism. Ce-based materials promote oxygen exchange associated with the high population of lattice oxygen species (O2-) denoted as OI type. The incorporation of praseodymium produces a Pr3+ enrichment that decrease the energy for oxygen release and increase oxygen mobility through surface and subsurface oxygen centers (OII type) depending on the synthesis procedure. For PtBaK catalyst, OIII species are responsible for oxygen exchange. Gas-solid reaction between soot and gas phase molecular oxygen is responsible for direct uncatalyzed soot oxidation. For ceria containing catalysts, low-temperature soot removal takes place through the intervention of lattice atomic species and superoxide species. For DPNR model catalyst, PtBaK/Al2O3, the soot elimination occurs with the intervention OIII type centers. In the presence NO, the assisted and cooperative mechanism due to NO2 and the intervention of the adsorbed nitrate species on the trimetallic catalyst enhances soot removal capacity.MCR acknowledges the postdoctoral fellowship obtained from the University of Malaga. MCR, CH, MAL and LJA want to thank the financial support of CTQ 2017-87909R project. MCR also want to thank the University of Alicante for the financial support for the internship (INV19-07). JCMM and AGG gratefully acknowledge the financial support of Generalitat Valenciana (PROMETEO/2018/076 project) and the Spanish Ministry of Science, Innovation and Universities (PID2019-105542RB-I00 project) and the UE-FEDER funding. JCMM also acknowledges Spanish Ministry of Science, Innovation and Universities for the financial support through a FPU grant (FPU17/00603)
Sources of hepatic triglyceride accumulation during high-fat feeding in the healthy rat
Hepatic triglyceride (HTG) accumulation from peripheral dietary sources and from endogenous de novo lipogenesis (DNL) was quantified in adult Sprague-Dawley rats by combining in vivo localized 1H MRS measurement of total hepatic lipid with a novel ex vivo 2H NMR analysis of HTG 2H enrichment from 2H-enriched body water. The methodology for DNL determination needs further validation against standard methodologies. To examine the effect of a high-fat diet on HTG concentrations and sources, animals (n = 5) were given high-fat chow for 35 days. HTG accumulation, measured by in vivo 1H MRS, increased significantly after 1 week (3.85 ± 0.60% vs 2.13 ± 0.34% for animals fed on a standard chow diet, P < 0.05) and was maintained until week 5 (3.30 ± 0.60% vs 1.12 ± 0.30%, P < 0.05). Animals fed on a high-fat diet were glucose intolerant (13.3 ± 1.3 vs 9.4 ± 0.8 mM in animals fed on a standard chow diet, for 60 min glycemia after glucose challenge, P < 0.05). In control animals, DNL accounted for 10.9 ± 1.0% of HTG, whereas in animals given the high-fat diet, the DNL contribution was significantly reduced to 1.0 ± 0.2% (P < 0.01 relative to controls). In a separate study to determine the response of HTG to weaning from a high-fat diet, animals with raised HTG (3.33 ± 0.51%) after 7days of a high-fat diet reverted to basal HTG concentrations (0.76 ± 0.06%) after an additional 7 days of weaning on a standard chow diet. These studies show that, in healthy rats, HTG concentrations are acutely influenced by dietary lipid concentrations. Although the DNL contribution to HTG content is suppressed by a high-fat diet in adult Sprague-Dawley rats, this effect is insufficient to prevent overall increases in HTG concentrations. Copyright © 2008 John Wiley & Sons, Ltd
Eliminación de carbonilla en gases de escape con catalizadores DeNOx. Determinación de parámetros cinéticos
Los catalizadores DeNOx se emplean en la eliminación de los óxidos de nitrógeno en vehículos diésel y, también, puede que entren en contacto con carbonilla o incluso sean utilizados como sistemas de reducción de NOx y soot simultáneamente (DPNR-Diesel Particulate NOx Reduction); por ello, es importante profundizar en el mecanismo de interacción entre el soot y el catalizador. Se ha utilizado un soot Printex U modelo y un catalizador Pt-K/Al2O3, con el potasio en forma de óxido e hidroxicarbonato hidratado. Se ha estudiado mediante TG-MS el proceso de eliminación en diferentes atmósferas oxidantes. Los procesos han sido desacoplados mediante el establecimiento de la función de distribución de energía de activación. En ausencia de catalizador, se produce la combustión del soot con el oxígeno molecular en fase gas a temperaturas alrededor de los 1100 K. En presencia de NO, la reducción tiene lugar a menor temperatura debido a su carácter más oxidante y a las especies de óxidos de nitrógeno retenidas y en fase gas. Si la carbonilla se encuentra en contacto con el catalizador Pt-K/Al2O3, los centros Pt-OH-K son los responsables de la eliminación vía gasificación a 780 K con una energía de activación alrededor de 85 kJ·mol-1.Os catalisadores do tipo DeNOx eliminam óxidos de nitrogênio em veículos a diesel e, também, podem entrar em contato com partículas ou até mesmo serem usados como sistemas de redução de NOx e carvão simultaneamente (DPNR-Diesel Particulate NOx Reduction); portanto, é importante aprofundar o mecanismo de interação entre a carvão e o catalisador. Carvão modelo Printex U e um catalisador Pt-K/Al2O3 foram utilizados, com potássio na forma de óxido e idroxicarbonato hidratado. O processo de eliminação em diferentes atmosferas oxidantes foi estudado mediante TG-MS. Os processos foram dissociados, estabelecendo a função de distribuição de energia de ativação. Na ausência de um catalisador, a combustão do carvão com o oxigênio molecular na fase gasosa ocorre a temperaturas em torno de 1100K. Na presença de NO, a redução ocorre a uma temperatura inferior devido ao seu caráter mais oxidante e às espécies de óxidos de nitrogênio retidos e na fase gasosa. Se o carbono estiver em contato com o catalisador Pt-K/Al2O3, os centros de Pt-OH-K são responsáveis pela eliminação via gaseificação a 780K com uma energia de ativação em torno de 85 kJ·mol-1.DeNOx catalysts eliminate nitrogen oxides in diesel vehicles and, in addition, can come in contact with soot or, even, be used as Diesel Particulate NOx Reduction (DPNR) material. Therefore, the understanding of the interaction mechanism between soot and catalyst is of high interest. The Printex U model soot and a Pt-K/Al2O3 catalyst have been used, with potassium in the form of oxide and hydrated hydroxycarbonate. The process of elimination in different oxidizing atmospheres has been studied by TG-MS. The processes have been decoupled by establishing the distribution function of activation energy. In the absence of catalyst, the combustion of the soot with the molecular oxygen in the gas phase occurs at temperatures around 1100K. In the presence of NO, the reduction takes place at a lower temperature due to its more oxidizing character and the species of nitrogen oxides retained and in the gas phase. If the carbon is in contact with the Pt-K/Al2O3 catalyst, the Pt-OH-K centers are responsible for the elimination via gasification at 780K with an activation energy around 85 kJ·mol-1
El papel de las transferencias sociales en la estabilidad demográfica de los núcleos rurales. A propósito de la provincia de Málaga
La despoblación y el envejecimiento están afectando a amplias áreas de bajas densidades de población y a cientos de núcleos en vías de extinción, especialmente en las zonas del interior de España. Además, estos procesos han llevado a ciertas áreas rurales a una preocupante situación de vulnerabilidad demográfica.
El objetivo de este trabajo es analizar el papel que están jugando determinados factores en la estabilidad de estos núcleos rurales más frágiles. Su análisis territorial se concretará en la provincia de Málaga y en el estudio de dos mecanismos de carácter social y de origen público: el subsidio de desempleo a la población agraria y el sistema de pensiones. Los resultados obtenidos confirman que, en las rentas de los municipios rurales, especialmente de los más pequeños, estos ingresos ocupan un lugar destacado, permitiendo mantener sus débiles y envejecidas poblaciones al sostener el nivel de vida de sus habitantes
El papel de las transferencias sociales en la estabilidad demográfica de los núcleos rurales. A propósito de la provincia de Málaga
The depopulation and aging is affecting large areas of low population densities and hundreds of population centres in danger of extinction in Spain, especially in the interior areas. Further this process has caused a situation of clear demographic vulnerability in certain rural areas. Therefore, the objective of this article is to analyse the role that certain factors are playing in the stability of the most fragile rural communities mentioned above. The territorial analysis will be carried out in the province of Malaga, and we will focus on the study of two mechanisms of public expenditure that have social relevance: the agricultural unemployment benefit and the pension system. The results we have obtained confirm that those external revenues mentioned occupy a prominent place in the incomes of rural municipalities, allowing them to maintain their weak and aging populations by sustaining the standard of living of their inhabitants.La despoblación y el envejecimiento están afectando a amplias áreas de bajas densidades de población y a cientos de núcleos en vías de extinción, especialmente en las zonas del interior de España. Además, estos procesos han llevado a ciertas áreas rurales a una preocupante situación de vulnerabilidad demográfica.
El objetivo de este trabajo es analizar el papel que están jugando determinados factores en la estabilidad de estos núcleos rurales más frágiles. Su análisis territorial se concretará en la provincia de Málaga y en el estudio de dos mecanismos de carácter social y de origen público: el subsidio de desempleo a la población agraria y el sistema de pensiones. Los resultados obtenidos confirman que, en las rentas de los municipios rurales, especialmente de los más pequeños, estos ingresos ocupan un lugar destacado, permitiendo mantener sus débiles y envejecidas poblaciones al sostener el nivel de vida de sus habitantes
Herramienta software para optimizar la utilización de sistemas electromagnéticos de prospección geofísica en la Arqueología
[ES] El objeto de esta ponencia es presentar una aplicación informática encaminada a optimizar las lecturas obtenidas con la utilización de un sistema de radar de subsuelo. Esta herramienta software ha sido contrastada mediante su empleo en el Conjunto Arqueológico de Baelo Claudia en Tarifa (estudio del decumanus maximus y localización de la entrada norte de la ciudad) y en prospecciones varias realizadas hasta la fecha por este grupo (localización de fosas para las asociaciones de memoria histórica de Málaga y Cádiz).[EN] This article shows the applicability of ground penetrating radar (GPR) to archaeological investigations, with the aid of a software that allows increasing the resolution of the measurements. This software has been applied for the first time in Baelo Claud in order to obtain information about city´s decumanus and the crossing with cardines minores Furthermore, the developed tools has also been used to locate in Málaga and Puerto Real (Cádiz) common graves where the remains of about 2,600 victims of the Spanish Civil War rest and the repression that came before and after the civil conflict.Guzmán Navarro, F.; Meco Gutiérrez, M.; Heredia Larrubia, J.; Pérez Hidalgo, F. (2010). Herramienta software para optimizar la utilización de sistemas electromagnéticos de prospección geofísica en la Arqueología. Virtual Archaeology Review. 1(1):111-115. https://doi.org/10.4995/var.2010.5130OJS11111511LORENZO, Enrique y HERNÁNDEZ, Mª Carmen. "Prospección geofísica en yacimientos arqueológicos con georadar en España. Dos casos: Numancia y el Paular". Física de la tierra, ISSN 0214-4557, Nº 7, 1995 (Ejemplar dedicado a: Geofísica aplicada) , pags. 193-206.GARCÍA VALIENTE, Mercedes et al. "Prospección geofísica aplicada a la Arqueología. Investigaciones en el circo romano de Mérida", 1997 . Mapping, ISSN 1131-9100, Nº 40, 1997 , pags. 16-20LORENZO, E., 1996. "Prospección Geofísica de Alta Resolución mediante Georadar. Aplicación a Obras Civiles". CEDEXSANJOSÉ BLASCO, J.J. 2002. "Comparación de los métodos geofísicos de prospección eléctrica y magnética para la localización de muros de piedra en un yacimiento arqueológico". Volver, especial abril 2002VEGA PÉREZ, Gracia, "Radar de subsuelo. Evaluación para aplicaciones en arqueología y en patrimonio histórico-artístico". Departamento de Ingeniería del Terreno, Cartográfica y Geofísica. Universidad Politécnica de Cataluña. Julio 2001CAICEDO HORNAZA, Bernardo et al, "Aplicaciones del georadar de subsuelo en obras civiles", 2003. Universidad de los Andes, Revista de Ingeniería, Nº 18, pags 32-4
Estudio DRIFTs-MS in situ de la oxidación de CO en condiciones subestequiométricas de oxígeno con un catalizador bimetálico Ni-Ce
El interés en la reducción de uno de los principales contaminantes atmosféricos como el monóxido de carbono hace que se hayan propuesto diversas técnicas para su eliminación. Actualmente, la oxidación catalítica a baja temperatura presenta gran interés, siendo los catalizadores soportados que contienen metales nobles, como Pt o Pd, los más estudiados. Los catalizadores bimetálicos Ni-Ce no soportados con alta área superficial han mostrado una importante población de vacantes de oxígeno, en comparación con sus equivalentes materiales soportados; mostrando un rendimiento considerable en la reacción de oxidación de CO, con prácticamente conversión completa por encima de los 460K. La actividad catalítica mejorada está relacionada con la presencia de la solución Ni-Ce-Ox que favorece las dos rutas involucradas en el mecanismo de oxidación de CO.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
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