A fast numerical model to calculate the thermal performance of a heat exchanger with rectangular PCM storage

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.The use of phase change materials (PCM) in heat exchangers for energy storage and release is under research. CFD modelling is extremely expensive regarding computational resources and time. For example, a PCM heat exchanger that would be used in a domestic heating system could reach a size of 0.8×0.6×0.6 m3, which is a lot to apply CFD commercial software. Nowadays, there is also a lack of knowledge about the thermal performance of these systems during the loading and unloading processes. Besides, many phase change substances can be used. This work presents an analysis of the thermal performance of a paraffin that would be used in a PCM heat exchanger of a heating system, being the operating temperatures of the heating fluid around 80 ºC at the supply and 30 ºC at the return. A fast model has been developed. This model takes into account the results of a CFD commercial model, but the knowledge of this model was summarized into useful polynomial equations. These equations, coupled with finite volume equations for the aluminium covering of the PCM and for the heating fluid, were implemented in a Matlab R2012a program and applied to a module consisting of two parallel flat plates separated by 30 mm thickness of PCM, which would be used in a heat exchanger. Two different spatial positions of the module, horizontal and vertical, and two phase change processes, melting and solidification, were studied. The horizontal position is faster than the vertical one, the melting time being nearly twice with respect to the vertical position. The results of the fast model were compared satisfactorily with the results of a full CFD model solved in Ansys Fluent 14.5. For the same boundary conditions in both models, the computational time diminishes from several weeks to few days.cf201

Redox regulation of methylthioadenosine phosphorylase in liver cells: molecular mechanism and functional implications

MTAP (5'-methylthioadenosine phosphorylase) catalyses the reversible phosphorolytic cleavage of methylthioadenosine leading to the production of methylthioribose-1-phosphate and adenine. Deficient MTAP activity has been correlated with human diseases including cirrhosis and hepatocellular carcinoma. In the present study we have investigated the regulation of MTAP by ROS (reactive oxygen species). The results of the present study support the inactivation of MTAP in the liver of bacterial LPS (lipopolysaccharide)-challenged mice as well as in HepG2 cells after exposure to t-butyl hydroperoxide. Reversible inactivation of purified MTAP by hydrogen peroxide results from a reduction of V(max) and involves the specific oxidation of Cys(136) and Cys(223) thiols to sulfenic acid that may be further stabilized to sulfenyl amide intermediates. Additionally, we found that Cys(145) and Cys(211) were disulfide bonded upon hydrogen peroxide exposure. However, this modification is not relevant to the mediation of the loss of MTAP activity as assessed by site-directed mutagenesis. Regulation of MTAP by ROS might participate in the redox regulation of the methionine catabolic pathway in the liver. Reduced MTA (5'-deoxy-5'-methylthioadenosine)-degrading activity may compensate for the deficient production of the precursor S-adenosylmethionine, allowing maintenance of intracellular MTA levels that may be critical to ensure cellular adaptation to physiopathological conditions such as inflammation

Unbalanced synaptic inhibition can create intensity-tuned auditory cortex neurons

Intensity-tuned auditory cortex neurons may be formed by intensity-tuned synaptic excitation. Synaptic inhibition has also been shown to enhance, and possibly even create intensity-tuned neurons. Here we show, using in vivo whole cell recordings in pentobarbital-anesthetized rats, that some intensity-tuned neurons are indeed created solely through disproportionally large inhibition at high intensities, without any intensity-tuned excitation. Since inhibition is essentially cortical in origin, these neurons provide examples of auditory feature-selectivity arising de novo at the cortex.Comment: 22 pages, 5 figure

Buenas prácticas de transferencia del conocimiento en la Universidad de Córdoba

La iniciativa consiste en proporcionar la materia prima. El proyecto, que se ha realizado con cerdos y ha tenido una duración de tres años, demuestra que la administración de Cardiotrofina-1 en el transplante hepático incrementa la supervivencia del animal, mejora su función cardiaca, respiratoria y renal, y también consigue reducir el daño hepatocelecuar y el estrés oxidativo y nitrosativo en el injerto

Revista del Consejo Superior de Investigaciones Científicas

Alimentación del meloncillo Herpestes ichneumon y de la gineta Genetta genetta en la Reserva Biológica de Doñana, S.O. de la Península Ibérica.Determinación de la edad en Rana perezi Seoane, 1885. Aplicación al análisis del crecimiento somático de poblaciones.Influencias ambientales en la variación del tamaño, forma y peso de los huevos de la collalba rubia (Oenanthe hispanica L.)Características de un coro de sapos corredores (Bufo calamita) en el sureste de España.Estrategias alimentarias del ciervo (Cervus elaphus L.) en Montes de ToledoDistribución de los quirópteros de la provincia de Orense (Noroeste de España).Ecología trófica del lince ibérico en Doñana durante un periodo secoDesarrollo larvario de la rana común (Rana perezi) (anura: ranidae) en charcas temporales del noroeste de la Península Ibérica.Régimen alimenticio del mirlo común (Turdus merula) en el sureste de la Península Ibérica durante el periodo otoño-invierno.Reproducción del gorrión molinero (Passer montanus) en las Islas Canarias.Relación entre la cobertura vegetal y la distribución de nidos en las colonias de pagaza piconegraPeer reviewe

Association of a single nucleotide polymorphism combination pattern of the Klotho gene with non-cardiovascular death in patients with chronic kidney disease

Chronic kidney disease (CKD) is associated with an elevated risk of all-cause mortality, with cardiovascular death being extensively investigated. However, non-cardiovascular mortality represents the biggest percentage, showing an evident increase in recent years. Klotho is a gene highly expressed in the kidney, with a clear influence on lifespan. Low levels of Klotho have been linked to CKD progression and adverse outcomes. Single nucleotide polymorphisms (SNPs) of the Klotho gene have been associated with several diseases, but studies investigating the association of Klotho SNPs with noncardiovascular death in CKD populations are lacking. The main aim of this study was to assess whether 11 Klotho SNPs were associated with non-cardiovascular death in a subpopulation of the National Observatory of Atherosclerosis in Nephrology (NEFRONA) study (n ¼ 2185 CKD patients). After 48 months of follow-up, 62 cardiovascular deaths and 108 non-cardiovascular deaths were recorded. We identified a high non-cardiovascular death risk combination of SNPs corresponding to individuals carrying the most frequent allele (G) at rs562020, the rare allele (C) at rs2283368 and homozygotes for the rare allele (G) at rs2320762 (rs562020 GG/AG þ rs2283368 CC/CT þ rs2320762 GG). Among the patients with the three SNPs genotyped (n ¼ 1016), 75 (7.4%) showed this combination. Furthermore, 95 (9.3%) patients showed a low-risk combination carrying all the opposite genotypes (rs562020 AA þ rs2283368 TT þ rs2320762 GT/TT). All the other combinations [n ¼ 846 (83.3%)] were considered as normal risk. Using competing risk regression analysis, we confirmed that the proposed combinations are independently associated with a higher fhazard ratio [HR] 3.28 [confidence interval (CI) 1.51-7.12]g and lower [HR 6 × 10- (95% CI 3.3 × 10--1.1 × 10-)] risk of suffering a non-cardiovascular death in the CKD population of the NEFRONA cohort compared with patients with the normal-risk combination. Determination of three SNPs of the Klotho gene could help in the prediction of non-cardiovascular death in CKD