Internal structure of the Nisa-Alburquerque batholith

The Late Variscan Nisa-Alburquerque batholith (SW-Iberian Peninsula) is located close to the boundary between two major geologic domains of the Iberian Massif: the Central Iberian Zone and the Ossa-Morena Zone. This baholith is made up of S-type granitic rocks with minor I-type ones. The main facies displays frequent magmatic orientations defined by the k-feldspar ± plagioclase phenocrysts. We have made six schematic cross sections perpendicular to the internal structure and to the elongated shape of the batholith. These sections show the internal structure of the batholith and the relationships between the different granitic facies. The cross-cutting relationships indicate that the general orientation was developed during the emplacement of the main granitic magma and prior to the differentiation/intrusion of the remaining facies. Diachronic eastward-progressing cooling of the granitic magma could explain some of the differences between the western and central-eastern domains of the batholith: sharp contacts and fabric tightening in western domains versus sinuous contacts, magma mixing and re-intrusion of different magmas, in centraleastern domain

Origin and provenance of igneous clasts from late Palaeozoic conglomerate formations (Del Ratón and El Planchón) in the Andean Precordillera of San Juan, Argentina

Late Palaeozoic conglomerate formations (Del Ratón and El Planchón) from the Andean Precordillera (Argentina) were studied to unravel their age, composition and provenance. The conglomerates from the Del Ratón Formation are formed by igneous clasts of acid, intermediate and basic compositions (volcanic and plutonic). Laser Ablation (ICP-MS) zircon U-Pb study has yielded an age of 348±2 Ma (late Tournaisian) for the crystallization of a granitic clast, interpreted as a maximum deposition age for the Del Ratón Formation. Geochemistry of these clasts (high LILE/HFSE and La/Yb ratios, negative Nb-Ta anomalies) suggests a calc-alkaline batholithic source, probably located along the Andean Frontal Cordillera currently to the west, where similar calc-alkaline igneous rocks have been described. The El Planchón Formation overlies the Del Ratón Formation and, in the studied conglomerates, there are only igneous clasts of mafic composition (volcanic/subvolcanic). These mafic clasts have a very similar petrography and geochemistry to the Late Ordovician mafic igneous rocks of the Western Precordillera (low LILE/HFSE and La/Yb ratios, no negative Nb-Ta anomalies). Therefore we suggest that the El Planchón conglomerate clasts were probably delivered mainly from northern sources within the Precordillera terrane. This change in clast provenance is tentatively related to a shift in mountain uplift from the Frontal Cordillera (in the west) to the Precordillera (in the east) after the early Visean.Las formaciones conglomeráticas del Paleozoico superior (Del Ratón y El Planchón) de la Precordillera Andina (Argentina) fueron es­tudiadas con el fin de determinar su edad, composición y procedencia. Los conglomerados de la Formación Del Ratón están constituidos por clastos de rocas ígneas (volcánicas y plutónicas) ácidas, intermedias y básicas. Un estudio en circones con espectrometría de masas con plasma acoplado por inducción con ablación láser (LA-ICP-MS) proporciona una edad de 348±2 Ma (Tournaisiense superior) para la cristalización de un clasto granítico, que interpretamos como la máxima edad del depósito de la Formación Del Ratón. La geoquímica de los clastos (altas relaciones LILE/HFSE y La/Yb, anomalías negativas de Nb-Ta) sugiere que probablemente derivan de batolitos calcoal­calinos descritos en algunos sectores de la Cordillera Frontal Andina localizada actualmente al oeste. La Formación El Planchón se super­pone a la Formación Del Ratón y los clastos estudiados en los conglomerados de esta formación son únicamente de rocas ígneas básicas (subvolcánicas/volcánicas). Estos clastos tienen una petrografía y geoquímica similar a las rocas ígneas máficas del Ordovícico Superior de la Precordillera Occidental (bajas relaciones LILE/HFSE y La/Yb, ausencia de anomalías negativas en Nb-Ta). Por ello nosotros suge­rimos que los clastos de los conglomerados de la Formación El Planchón proceden de materiales localizados al norte dentro de la propia Precordillera. Este cambio en la procedencia de los clastos es tentativamente relacionado con una transferencia de la deformación desde la Cordillera Frontal (al oeste) a la Precordillera (al este), provocando el levantamiento de la Precordillera a partir del Viseense inferior

Variscan metamorphism and hydrothermalism recorded in lower Cambrian carbonates (Toledo Mountains, Central Iberian Zone, Spain)

Las rocas carbonáticas del Cámbrico inferior de la Zona Centroibérica (Formación Calizas de Los Navalucillos) presentan en la localidad de Urda (Toledo) asociaciones minerales que pueden estar producidas por procesos metamórficos variscos. La textura y mineralogía observadas consisten en dominios siliciclásticos de cuarzo + sericita ± micrita en contacto con nódulos carbonáticos con bioclastos de arqueociatos. Los bordes de estos nódulos contienen biotita magnesiana ± clorita-clinocloro ± óxidos y sulfuros de hierro ± feldespato potásico. Fuera de los bordes y en la matriz siliciclástica suelen aparecer biotita magnesiana ± moscovita ± feldespato potásico ± clorita-clinocloro ± titanita ± plagioclasa cálcica y sulfuros de hierro. La modelización P-T-XCO2 indica condiciones de baja presión, temperaturas de 310-355 oC y composición del fluido de 0.05-0.55 XCO2 para producir las paragénesis minerales observadas. En base a estos datos se consideran dos hipótesis: 1) Un metamorfismo regional varisco que afectó a rocas compuestas por cuarzo + sericita + calcita/dolomita. 2) Un metamorfismo de contacto asociado al emplazamiento tardivarisco de un plutón granítico, que generó de forma puntual calor y fluidos hidrotermales de H2O ± CO2. Estos fluidos serían en parte magmáticos-graníticos (>H2O) y en parte metamórficos (>CO2) procedentes de los metasedimentos de contacto.The early Cambrian carbonate rocks of the Central Iberian Zone (Navalucillos Limestone Formation) show in Urda location (Toledo) a mineral paragenesis probably linked to Variscan metamorphic processes. The textures consist in quartz + sericite ± micrite domains that include calcite nodules with archaeocyathan bioclasts and silicate rims of Mg-biotite ± clinochlore ± iron-oxides and sulfides ± K-feldspar. Outside the rims, the silicate phases are Mg-biotite ± muscovite ± K-feldspar ± chlorite-clinochlore ± titanite ± calcic-plagioclase, and iron sulfides. P-T-XCO2 modeling indicates low pressure conditions of metamorphism, low to moderate XCO2 fluid (≈ 0.1-0.5) and a T range of ≈ 300-355 ºC. Two hypothesis are considered: 1) Regional metamorphism of a quartz + sericite + calcite/dolomite assemblage. 2) Infiltration of the carbonate rocks by H2O ± CO2 external fluids, magmatic/metamorphic derived. This consists in hydrothermal inputs from a local source (granite intrusions) and from dehydration of contact sediments. The high variability of the isotopic δ18O values in the carbonates supports this hypothesis.Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEMinisterio de Economía y Competitividad (MINECO)pu

Thioredoxin 1 modulates apoptosis induced by bioactive compounds in prostate cancer cells

Accumulating evidence suggests that natural bioactive compounds, alone or in combination with traditional chemotherapeutic agents, could be used as potential therapies to fight cancer. In this study, we employed four natural bioactive compounds (curcumin, resveratrol, melatonin, and silibinin) and studied their role in redox control and ability to promote apoptosis in androgen sensitive and insensitive prostate cancer cells. Here is shown that curcumin and resveratrol promote ROS production and induce apoptosis in LNCaP and PC-3. An increase in reactive species is a trigger event in curcumin-induced apoptosis and a consequence of resveratrol effects on other pathways within these cells. Moreover, here we demonstrated that these four compounds affect differently one of the main intracellular redox regulator, the thioredoxin system. Exposure to curcumin and resveratrol promoted TRX1 oxidation and altered its subcellular location. Furthermore, resveratrol diminished TRX1 levels in PC-3 cells and increased the expression of its inhibitor TXNIP. Conversly, melatonin and silibinin only worked as cytostatic agents, reducing ROS levels and showing preventive effects against TRX oxidation. All together, this work explores the effect of compounds currently tested as chemo-preventive agents in prostate cancer therapy, on the TRX1 redox state and function. Our work shows the importance that the TRX system might have within the differences found in their mechanisms of action. These bioactive compounds trigger different responses and affect ROS production and redox systems in prostate cancer cells, suggesting the key role that redox-related pathways might play in processes like differentiation or survival in prostate cancer. Keywords: Thioredoxin, Thioredoxin reductase, TXNIP, Prostate cancer, Redox signaling, Apoptosi

Validation of SPM analysis of visual activation in rat brain pet studies

[Abstract] AMI Annual Conference 2004, March 27-31, Orlando, FloridaStatistical parametric mapping (SPM) is used to detect subtle activity changes in brain not requiring a priori assumptions about the expected activations. We adapt the methodology for analyzing rat brain positron emission tomography (PET) scansPublicad

Fully 3D GPU PET reconstruction

Fully 3D iterative tomographic image reconstruction is computationally very demanding. Graphics Processing Unit(GPU) has be enproposed formany years as potential accelerators incomplex scientific problems, but it has not be enuseduntil there cent advances in the programmability of GPU sthat the best available reconstruction code shave started tobe implemented toberunon GPUs. This work presents a GPU based fully 3D PET iterative reconstruction sofware. This new code may reconstruct sinogram data from several commercially available PET scanners. The most important and time consuming part soft he code,the forward and backward projection operations, arebasedonan accurate model of the scanner obtained with the MonteCarlo code PeneloPET and they have been massively parallelize don the GPU.For the PET scanners considered, the GPU based code is more than 70 times faster than asimilar code running on a single core of a fast CPU, obtainingin both cases the same images. The code has been designed to be easily adapted to reconstruct sinograms from any other PET scanner, including scanner prototypes.This work has been supported by MEC(FPA200762216), UCM (Grupos UCM,910059), CPAN(Consolider Ingenio 2010) CSPD 200700042,the RECAVARETIC network, ARTEMISS2009/ DPI 1802, European Regional Development,ENTEPRASE grant, PSE 30000020095 and TEC20080675C0201, Ministerio de Ciencia e Innovación, Spanish Government.Publicad

Imagen de alta resolución en pequeños animales de laboratorio

La posibilidad de visualizar y cuantificar la función de un determinado órgano en animales de laboratorio es una herramienta científica de gran importancia en el estudio de modelos de enfermedades humanas, en el descubrimiento y desarrollo de nuevos medicamentos y en la caracterización del fenotipo de animales transgénicos y noqueados. La tomografía por emisión de positrones (PET) y la imagen proyectiva de radiofármacos marcados con emisores de positrones proporcionan una herramienta genérica y no invasiva para la investigación científica en los casos anteriormente expuestos. En este trabajo se describe un sistema mutimodal PET/CT basado en cámaras de coincidencia y detectores de estado sólido para los rayos X, diseñado para adquirir tanto imágenes tomográficas como de proyección con alta resolución temporal, con capacidad para visualizar ratas y ratones, estos últimos en cuerpo completo en un solo campo de visión.Publicad

Positron range effects in high resolution 3D PET imaging

Proceeding of: 2009 IEEE Nuclear Science Symposium Conference Record (NSS/MIC), Orlando, Florida, 25-31 October 2009Positron range limits the spatial resolution of PET images. It has a different effect for different isotopes and propagation materials, therefore it is important to consider it during image reconstruction, in order to obtain the best image quality. Positron range distribution was computed using Monte Carlo simulations with PeneloPET. The simulation models positron trajectories and computes the spatial distribution of the annihilation coordinates for the most common isotopes used in PET: 18F, 11C, 13N, 15O, 68Ga and 82Rb. Range profiles are computed for different positron propagation materials, obtaining one kernel profile for each isotope-material combination. These range kernels were introduced in FIRST, a 3D-OSEM image reconstruction software, and employed to blur the object during forward projection. The blurring introduced takes into account the material in which the positron is annihilated, obtained for instance from a CT image. In this way, different positron range corrections for each material in the phantom are considered. We compare resolution and noise properties of the images reconstructed with and without positron range modelling. For this purpose, acquisitions of an Image Quality phantom filled with different isotopes have been simulated for the ARGUS small animal PET scanner.This work has been supported in part by MEC (FPA2007 62216), CDTEAM (Programa CENIT, Ministerio de Industria), UCM (Grupos UCM, 910059), CPAN (Consolider Ingenio 2010) CSPD 2007 00042 and the RECAVA RETIC network. Part of the calculations of this work were performed in the “Clúster de Cálculo de Alta Capacidad para Técnicas Físicas” funded in part by UCM and in part by UE under FEDER programme”