Effect of different interpolation methods on the accuracy of the reconstruction of spiral k-space trajectories in MRI

[Poster] 4th European Molecular Imaging Meeting, Barcelona, Spain, May 27 - 30, 2009This work is supported in part by the projects CdTeaM (CeniT-ingenio 2010), Ministerio de Ciencia e innovación, and Ciber Cb07/09/0031 CiberSaM, Ministerio de Sanidad y Consumo.Publicad

Fat composition assessment by 1H and 13C spectroscopy in mice

Proceeding of: 17th Scientific Meeting, International Society for Magnetic Resonance in Medicine, 18-24 April, 2009, Honolulu, Hawai, US

Quantitative comparison of partial fourier reconstruction algorithms in MRI at 7T

[Poster] 4th European Molecular Imaging Meeting, Barcelona, Spain, May 27 - 30, 2009In this work we present a quantitative comparison at 7T of the most common partial fourier reconstruction algorithms: conjugate synthesis with phase correction, Margosian method, homodyne reconstruction, PoCS algorithm and iterative homodyne reconstructionThis work is supported in part by the projects CdTeaM (CeniT-ingenio 2010), Ministerio de Ciencia e innovación, and Ciber Cb07/09/0031 CiberSaM, Ministerio de Sanidad y Consumo.Publicad

Uso del método de Split Bregman para la resolución del problema de compressed sensing en imagen de resonancia magnética dinámica cardiaca para pequeño animal

Actas de: XXIX Congreso Anual de la Sociedad Espñaola de Ingeniería Biomédica (CASEIB 2011). Cáceres, 16-18 Noviembre 2011.La imagen dinámica de resonancia magnética en pequeño animal es una herramienta muy importante en el estudio de enfermedades cardiovasculares. La reducción de los tiempos de adquisición de este tipo de imágenes es especialmente relevante para la obtención de imágenes de calidad con una buena resolución espacial y temporal. Actualmente existen diversas técnicas de aceleración que permiten reducir estos tiempos de adquisición, entre ellas la técnica de 'compressed sensing', en auge en los últimos años. Ésta técnica permite la reconstrucción de una imagen a partir de datos submuestreados mediante el uso de métodos de reconstrucción no lineales que minimizan la variación total de la imagen. Recientemente el método de Split Bregman ha demostrado ser computacionalmente eficiente para resolver este problema en imágenes de resonancia magnética. En este trabajo se amplía la metodología de Split Bregman para minimizar la variación total espacial y temporal en imágenes dinámicas, y se aplica a imágenes cardiacas de pequeño animal. Los resultados preliminares muestran que con la metodología propuesta es posible reducir el tiempo de adquisición hasta 5 veces manteniendo la calidad de imagen.Este trabajo ha sido financiado parcialmente por el Ministerio de Ciencia e Innovación (Red RECAVA) y la Comunidad de Madrid y los Fondos FEDER (proyecto ARTEMIS-S2009DPI-1802)Publicad

Validation of rat brain MR image intensity non-uniformity correction using surface coil images

[Poster] 4th European Molecular Imaging Meeting, Barcelona, Spain, May 27 - 30, 2009Non-uniform intensity artifacts confound the quantitative analysis of magnetic resonance (Mr) images of animal studies, particularly when using surface coils and high-field magnets. The use of correction methods proposed and validated on human brain images such as the n3 algorithm has previously been reported only on mouse images acquired with a volume coil. here, we evaluate the performance of n3 specifically on Mr rat brain images acquired with a surface coilCdTeaM (CeniT-ingenio 2010), Ministerio de Ciencia e innovación, Ciber Cb07/09/0031 CiberSaM, Ministerio de Sanidad y ConsumoPublicad

Quantification of SPIO using T2* and phase imaging

Proceeding of: 17th Scientific Meeting, International Society for Magnetic Resonance in Medicine, 18-24 April, 2009, Honolulu, Hawai, USAPublicad

Inverted metallicity gradients in two Virgo cluster star-forming dwarf galaxies: evidence of recent merging?

We present integral field spectroscopy observations of two star-forming dwarf galaxies in the Virgo cluster (VCC135 and VCC324) obtained with PMAS/PPak at the Calar Alto 3.5 meter telescope. We derive metallicity maps using the N2 empirical calibrator. The galaxies show positive gas metallicity gradients, contrarily to what is usually found in other dwarfs or in spiral galaxies. We measure gradient slopes of 0.20 $\pm$ 0.06 and 0.15 $\pm$ 0.03 dex/$R_e$ for VCC135 and VCC324, respectively. Such a trend has been only observed in few, very isolated galaxies, or at higher redshifts ($z >$ 1). It is thought to be associated with accretion of metal-poor gas from the intergalactic medium, a mechanism that would be less likely to occur in a high-density environment like Virgo. We combine emission line observations with deep optical images to investigate the origin of the peculiar metallicity gradient. The presence of weak underlying substructures in both galaxies and the analysis of morphological diagnostics and of ionised gas kinematics suggest that the inflow of metal-poor gas to the central regions of the dwarfs may be related to a recent merging event with a gas-rich companion.Comment: 13 pages, 9 figures, MNRAS in press. V2: minor figure revisions and minor title change

Indefinites in comparatives

The goal of this paper is to explain the meaning and distribution of indefinites in comparatives, focusing on English some and any and German irgend-indefinites. We consider three competing theories of comparatives in combination with an alternative semantics of some and any, and a novel account of stressed irgend-indefinites. One of the resulting accounts, based on Heim’s analysis of comparatives, predicts all the relevant differences in quantificational force, and explains why free choice indefinites are licensed in comparatives

Human amylin aggregates release within exosomes as a protective mechanism in pancreatic β cells: Pancreatic β-hippocampal cell communication

Pancreatic β cells are essential in the maintenance of glucose homeostasis during the progression to type 2 Diabetes Mellitus (T2DM), generating compensatory hyperinsulinemia to counteract insulin resistance. It is well known, that throughout the process there is an increased mTORC1 signaling pathway, with an impairment in different quality control systems including ubiquitin-proteasome system and autophagy. In addition, under this situation, pancreatic β cells start to accumulate amylin protein (IAPP) in aggregates, and this accumulation contributes to the failure of autophagy, damaging different organelles such as plasma membrane, endoplasmic reticulum, mitochondria, and others. Here, we report that IAPP can be incorporated to multivesicular bodies (MVB) and secreted into exosomes, a mechanism responsible for the exportation of these toxic aggregates as vehicles of cell to cell communication. On this regard, we have demonstrated that the exosomes bearing toxic hIAPP released from pancreatic β cells are capable to induce hyperactivation of mTORC1 signaling, a failure in the autophagic cellular quality control, and favor pro-fission status of the mitochondrial dynamics in hippo-campal cells. In summary, our results show that harmful accumulation of hIAPP in pancreatic β cells may be detoxified by the release of exosomes, which may be captured by endocytosis mechanism damaging neuronal hippocampal cells, which suggest an underlying molecular mechanism to the link between type 2 diabetes and neurodegenerative diseases