233 research outputs found

    Preferencias y aceptabilidad de los consumidores por la carne de vacuno enriquecida en omega-3 y ácido linoleico conjugado en tres ciudades españolas

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    Este trabajo analiza las preferencias de los consumidores en tres ciudades españolas (Barcelona, Zaragoza y Pamplona) con el objetivo de estimar la importancia relativa de los atributos más relevantes de la carne de vacuno incluyendo su enriquecimiento con ácidos grasos no saturados como el omega-3 (n-3) y el ácido linoleico conjugado (CLA). Asimismo, se pretende estudiar el impacto de la experiencia sensorial y la información sobre las preferencias y la heterogeneidad no observada tanto del factor de escala como de los atributos. Los datos fueron recogidos de un cuestionario estructurado y auto-completado en un ambiente controlado con dos muestras diferentes (320 y 325 consumidores) diferenciados por la información recibida. El experimento de elección fue aplicado antes y después de que los mismos consumidores evaluaran la aceptabilidad de la carne enriquecida. Para el análisis de datos se ha empleado el modelo Multinomial Generalizado (GMNL). Los resultados mostraron un impacto significativo de la información y la experiencia sensorial sobre las preferencias. La utilidad de la carne enriquecida con n-3 en las tres ciudades se incrementó significativamente después de probar la carne, sobre todo para los consumidores que no recibieron información, mientras que la utilidad de la carne enriquecida con CLA no fue significativa independientemente de la evaluación hedónica o la información proporcionada. Después de la experiencia sensorial, la heterogeneidad de escala, que es la variación del grado de aleatoriedad en el proceso de toma de decisiones y por lo tanto el grado de certeza de los individuos en sus elecciones, ha disminuido significativamente. Finalmente, los resultados mostraron un aumento de la aceptabilidad global de la carne enriquecida con n-3 y CLA respecto a la carne convencional y la información ofrecida a los consumidores no tuvo ningún impacto significativo en sus puntuaciones.Publishe

    The increase of the functional entropy of the human brain with age

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    We use entropy to characterize intrinsic ageing properties of the human brain. Analysis of fMRI data from a large dataset of individuals, using resting state BOLD signals, demonstrated that a functional entropy associated with brain activity increases with age. During an average lifespan, the entropy, which was calculated from a population of individuals, increased by approximately 0.1 bits, due to correlations in BOLD activity becoming more widely distributed. We attribute this to the number of excitatory neurons and the excitatory conductance decreasing with age. Incorporating these properties into a computational model leads to quantitatively similar results to the fMRI data. Our dataset involved males and females and we found significant differences between them. The entropy of males at birth was lower than that of females. However, the entropies of the two sexes increase at different rates, and intersect at approximately 50 years; after this age, males have a larger entropy

    Magnetic and structural characterization of thiol capped ferromagnetic Ag nanoparticles

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    Dodecanethiol capped Ag nanoparticles (NPs) have been independently synthesized by the well-known Brust method under the same physical-chemical conditions. The obtained NP present similar sizes ( ∼ 2 nm) but different magnetic behaviors. The extended x-ray absorption fine structure analyses at the K-edge of Ag did not reveal any noticeable structural nor topological differences among the samples. In clear contrast with the structure provided for thiol capped ferromagnetic Au NPs, the analysis also brings out the existence of Ag–S bonds in a diffuse region surrounding a reduced Ag core where the magnetism of the Ag NPs would be located. This record was migrated from the OpenDepot repository service in June, 2017 before shutting down

    Tracing of temporo-entorhinal connections in the human brain: cognitively impaired argyrophilic grain disease cases show dendritic alterations but no axonal disconnection of temporo-entorhinal association neurons

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    Argyrophilic grain disease (AGD), a neurodegenerative disorder, is often associated with mild to moderate Alzheimer’s disease (AD)-related pathology. The development of dementia in AGD is associated with the extent of coexisting AD-related pathology. Therefore, the question arises whether the degenerative changes in the neuronal network of demented AGD-patients represent a distinct pattern or show similar changes of disconnection as considered for AD. We were able to apply DiI-tracing in two human autopsy cases with mild AD-related pathology (controls), in one AD-patient, in one non-demented patient with advanced AD-related pathology, and in three cognitively impaired AGD-patients. DiI-crystals were injected into the entorhinal cortex. Pyramidal neurons of layers III and V of the adjacent temporal neocortex (area 35) were retrogradely marked with the tracer and analyzed. The AD case did not exhibit any retrogradely labeled neurons in the temporal neocortex. In the non-demented case with advanced AD-related pathology, the number of traced neurons was reduced as compared to that in the two controls and in the three AGD cases. In contrast, all three cognitively impaired AGD cases exhibited labeled pyramidal neurons in area 35 in an almost similar number as in the controls. However, alterations in the dendritic tree were observed in the AGD cases. These results show the existence of temporo-entorhinal connections in the adult human brain similar to those reported in animal models. Furthermore, the present study based on seven cases is the first attempt to study changes in the neuronal network in a human tauopathy with targeted axonal tracing techniques. Our findings in three cognitively impaired AGD cases suggest that AGD-related dementia constitutes a distinct disorder with a characteristic pattern of degeneration in the neuronal network

    Characterization of PTZ-Induced Seizure Susceptibility in a Down Syndrome Mouse Model That Overexpresses CSTB

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    Down syndrome (DS) is a complex genetic syndrome characterized by intellectual disability, dysmorphism and variable additional physiological traits. Current research progress has begun to decipher the neural mechanisms underlying cognitive impairment, leading to new therapeutic perspectives. Pentylenetetrazol (PTZ) has recently been found to have positive effects on learning and memory capacities of a DS mouse model and is foreseen to treat DS patients. But PTZ is also known to be a convulsant drug at higher dose and DS persons are more prone to epileptic seizures than the general population. This raises concerns over what long-term effects of treatment might be in the DS population. The cause of increased propensity for epilepsy in the DS population and which Hsa21 gene(s) are implicated remain unknown. Among Hsa21 candidate genes in epilepsy, CSTB, coding for the cystein protease inhibitor cystatin B, is involved in progressive myoclonus epilepsy and ataxia in both mice and human. Thus we aim to evaluate the effect of an increase in Cstb gene dosage on spontaneous epileptic activity and susceptibility to PTZ-induced seizure. To this end we generated a new mouse model trisomic for Cstb by homologous recombination. We verified that increasing copy number of Cstb from Trisomy (Ts) to Tetrasomy (Tt) was driving overexpression of the gene in the brain, we checked transgenic animals for presence of locomotor activity and electroencephalogram (EEG) abnormalities characteristic of myoclonic epilepsy and we tested if those animals were prone to PTZ-induced seizure. Overall, the results of the analysis shows that an increase in Cstb does not induce any spontaneous epileptic activity and neither increase or decrease the propensity of Ts and Tt mice to myoclonic seizures suggesting that Ctsb dosage should not interfere with PTZ-treatment
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