Estratigrafía del Paleógeno en la zona de tránsito entre la Codillera prelitoral Catalana y el Prepirineo

El estudio de la serie eocénica de El Far-Puig del Moro (Gerona) y la subsiguiente comparación con el Eoceno de Vic (Barcelona), permite situar la estratigrafía del Eoceno inferior y medio en la zona de tránsito entre la Cordillera Prelitoral y el Prepirineo. A través de unidades litostratigráficas detalladamente descritas, así como de las atribuciones cronostratigráficas,se tiene una visión útil para las investigaciones posteriores ya iniciadas sobre el Eoceno pirenaico y subpirenaico

Estratigrafía del Paleógeno en la zona de tránsito entre la Codillera prelitoral Catalana y el Prepirineo

El estudio de la serie eocénica de El Far-Puig del Moro (Gerona) y la subsiguiente comparación con el Eoceno de Vic (Barcelona), permite situar la estratigrafía del Eoceno inferior y medio en la zona de tránsito entre la Cordillera Prelitoral y el Prepirineo. A través de unidades litostratigráficas detalladamente descritas, así como de las atribuciones cronostratigráficas,se tiene una visión útil para las investigaciones posteriores ya iniciadas sobre el Eoceno pirenaico y subpirenaico

Epitaxial stabilization of ε-Fe2O3 (00l) thin films on SrTiO3 (111)

This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.Thin films of the metastable and elusive ε-Fe2O3 have been epitaxially stabilized on SrTiO3 (111) substrates. The ε-Fe2O3 films present a (001) orientation perpendicular to the substrate and three in-plane domains measuring a few nanometers and showing atomically sharp interfaces. We argue that this domain structure, rather than the epitaxial-strain, plays an essential role in stabilizing the ε-Fe2O3 by minimizing the energy of (100) surfaces. The ε-Fe2O3 films show a large in-plane coercivity ∼ 8 kOe which combined with the magnetoelectric character claimed for this oxide may lead to novel applications in spintronics

Unveiling a New High-Temperature Ordered Magnetic Phase in ϵ-Fe2O3

Iron oxides are among the most abundant materials on Earth, and yet there are some of their basic properties which are still not well-established. Here, we present temperature-dependent magnetic, X-ray, and neutron diffraction measurements refuting the current belief that the magnetic ordering temperature of ϵ-FeO is ∼500 K, i.e., well below that of other iron oxides such as hematite, magnetite, or maghemite. Upon heating from room temperature, the ϵ-FeO nanoparticles' saturation magnetization undergoes a monotonic decrease while the coercivity and remanence sharply drop, virtually vanishing around ∼500 K. However, above that temperature the hysteresis loops present a nonlinear response with finite coercivity, making evident signs of ferrimagnetic order up to temperatures as high as 850 K (T). The neutron diffraction study confirms the presence of ferrimagnetic order well above 500 K with Pna'2' magnetic symmetry, but only involving two of the four Fe sublattices which are ordered below T ≈ 480 K, and with a reduced net ferromagnetic component, that vanishes at above 850 K. The results unambiguously show the presence of a high-temperature magnetic phase in ϵ-FeO with a critical temperature of T ∼ 850 K. Importantly, this temperature is similar to the Curie point in other iron oxides, indicating comparable magnetic coupling strengths. The presence of diverse magnetic phases is further supported by the nonmonotonic evolution of the thermal expansion. The existence of a high-temperature ferrimagnetic phase in ϵ-FeO may open the door to further expand the working range of this multifunctional iron oxide

Indoor falls and number of previous falls are independent risk factors for long-term mortality after a hip fracture

Hip fractures are almost always the result of a fall. Causes and circumstances of falls may differ between frail and vigorous patients. To describe the circumstances of falls causing hip fractures, number of falls during the previous year, and their association with long-term mortality. The study is a retrospective review conducted in a tertiary university hospital serving a population of 425,000 inhabitants in Barcelona. All patients admitted with hip fractures with medical records describing the circumstances and number of previous falls were included. The number of falls in the previous 12 months was recorded, including the one causing the fracture. The circumstances of the index fall were dichotomized according to whether it was from the patient's own height or above; day or night; indoors or outdoors, due to intrinsic or extrinsic causes. Cumulative mortality was recorded for almost 5 years after hip fracture. Indoor falls were strongly associated with shorter survival. Falling more than once in the previous year was also a risk factor for long-term mortality (hazard ratio 1.461, p < 0.001 and hazard ratio 1.035, p = 0.008 respectively). Indoor falls and falling more than once in the previous year are long-term risk factors for mortality after hip fractures. It is always essential to take a careful patient history on admission to determine the number of falls and their circumstances, and special care should be taken to reduce mortality in patients at high risk

Nanopartícules magnètiques en matrius de sílice

Descripció del recurs: el 21 setembre 2011En aquest treball s'han estudiat diferents aproximacions a la síntesi de compòsits de nanopartícules magnètiques en matrius de sílice de tipus aerogel o xerogel. Així, s'han obtingut materials amb propietats molt diferents tant pel que fa al seu magnetisme (materials durs o tous), a les seves propietats òptiques (transparents, opacs, anisotròpics) o la seva densitat, i se n'han estudiat algunes de les seves possibles aplicacions magnetoòptiques. Les matrius de sílice en forma de xerogel també s'han fet servir per a estabilitzar, gràcies al confinament, l'ε-Fe2O3, un polimorf metastable d'óxid de Fe (III) molt poc conegut. S'ha fet una caracterització de les propietats magnètiques del material i s'ha vist que la seva temperatura de Curie és de 510 K i que a temperatura ambient és un ferrimagnet colineal amb una imantació moderada (20 emu/g a saturació) i una anisotropia magnètica elevada que fan que la seva coercitivitat sigui molt elevada per a un òxid de Fe (20 kOe). Entre 150 i 80 K l'ε-Fe2O3 presenta una transició de fase magnètica i estructural de segon ordre que té com a resultat l'aparició d'una estructura magnètica incommensurada de tipus "ona quadrada". S'ha posat de manifest que coincidint amb aquesta transició de fase, el material presenta un acoblament magnetoelèctric.In this Thesis, different approximations to the synthesis of composites of magnetic nanoparticles in silica aerogel or xerogel matrices have been studied. In particular, we have obtained materials with a range of different properties regarding its magnetism (hard or soft magnetic materials), optical properties (transparent, opaque, anisotropic) or density and we have studied its potential magneto-optical applications. The xerogel matrices have also been used to stabilize by confinement a rare iron (III) oxide polymorph, the ε-Fe2O3, which has not been much studied so far. The magnetic properties of the polymorph have been studied in detail and it has been established that it has a Curie temperature of 510 K. At room temperature, it presents a collinear ferromagnetic order with a moderate magnetization (20 emu/g at saturation) and a large magnetic anisotropy which result in a huge coercivity of about 20 kOe. Between 150 and 80 K, ε-Fe2O3 presents a second order magnetic and structural transition to a "square-wave" incommensurate magnetic order. Concomitantly with this transition it has been shown that the material presents a magnetoelectric coupling.En este trabajo se han estudiado diferentes aproximaciones a la síntesis de composites de nanopartículas magnéticas en matrices de sílice de tipo aerogel o xerogel. Así, se han obtenido materiales con propiedades muy distintas tanto en relación a su magnetismo (materiales duros o blandos), a les sus propiedades ópticas (transparentes, opacos, anisotrópicos) o a su densidad, y se han estudiado algunas de sus posibles aplicaciones magnetoópticas. Las matrices de sílice en forma de xerogel también se han utilizado para estabilizar, gracias al confinamiento, el ε-Fe2O3, un polimorfo metaestable de óxido de Fe (III) muy poco conocido. Se ha hecho una caracterización de sus propiedades magnéticas y se ha establecido que su temperatura de Curie es de 510 K y que a temperatura ambiente es un ferrimagneto co-lineal con una imantación moderada (20 emu/g a saturación) y una anisotropía magnética elevada que hacen que su coercitividad sea muy elevada para un óxido de Fe (20 kOe). Entre 150 i 80 K el ε-Fe2O3 presenta una transición de fase magnética y estructural de segundo orden que da lugar a una estructura magnética inconmensurable de tipo "onda cuadrada". Se ha puesto de manifiesto que coincidiendo con esta transición de fase, el material presenta un acoplamiento magnetoeléctrico

Magnetic Mesoporous Silica Nanorods Loaded with Ceria and Functionalized with Fluorophores for Multimodal Imaging

Multifunctional magnetic nanocomposites based on mesoporous silica have a wide range of potential applications in catalysis, biomedicine, or sensing. Such particles combine responsiveness to external magnetic fields with other functionalities endowed by the agents loaded inside the pores or conjugated to the particle surface. Different applications might benefit from specific particle morphologies. In the case of biomedical applications, mesoporous silica nanospheres have been extensively studied while nanorods, with a more challenging preparation, have attracted much less attention despite the positive impact on the therapeutic performance shown by seminal studies. Here, we report on a sol-gel synthesis of mesoporous rodlike silica particles of two distinct lengths (1.4 and 0.9 μm) and aspect ratios (4.7 and 2.2) using Pluronic P123 as a structure-directing template and rendering ∼1 g of rods per batch. Iron oxide nanoparticles have been synthesized within the pores yielding maghemite (γ-FeO) nanocrystals of elongated shape (∼7 nm × 5 nm) with a [110] preferential orientation along the rod axis and a superparamagnetic character. The performance of the rods as T-weighted MRI contrast agents has also been confirmed. In a subsequent step, the mesoporous silica rods were loaded with a cerium compound and their surface was functionalized with fluorophores (fluorescamine and Cyanine5) emitting at λ = 525 and 730 nm, respectively, thus highlighting the possibility of multiple imaging modalities. The biocompatibility of the rods was evaluated in vitro in a zebrafish (Danio rerio) liver cell line (ZFL), with results showing that neither long nor short rods with magnetic particles caused cytotoxicity in ZFL cells for concentrations up to 50 μg/ml. We advocate that such nanocomposites can find applications in medical imaging and therapy, where the influence of shape on performance can be also assesse

Síntomas psicopatológicos en pacientes afectos de cefalea crónica con o sin fibromialgia

La presencia de sintomatología psicopatológica, como la ansiedad y la depresión, en las cefaleas crónicas y en la fibromialgia es común. Objetivos. Estudiar si existen diferencias en el perfil psicopatológico entre pacientes con cefalea crónica y fibromialgia (CCFM) y pacientes con cefalea crónica sin fibromialgia (CC), y si existen diferencias en la respuesta al tratamiento entre ambos grupos. Pacientes y métodos. Se administra una batería de test de evaluación de síntomas psicopatológicos a 30 pacientes con CC y a 30 pacientes con CCFM diagnosticados por un reumatólogo. Incluimos en la CC a pacientes con migraña crónica y cefalea tensional crónica. El diseño es con datos apareados de edad y sexo. Se comparan las puntuaciones de depresión, ansiedad, obsesión y perfil de sintomatología psicopatológica -inventario multifásico de personalidad de Minnessota (MMPI-2) y cuestionario de 90 síntomas revisado (SCL-90-R)- (prueba t). Se correlacionan los datos con la respuesta al tratamiento. Resultados. Los pacientes con CCFM muestran puntuaciones significativamente superiores en las escalas de hipocondriasis, depresión, histeria, paranoia, psicastenia y esquizofrenia (MMPI-2), y más somatizaciones, obsesión y ansiedad según el SCL-90-R. La respuesta favorable al tratamiento es inferior en el grupo CCFM (17,85%) que en el CC (42,85%). La hipocondriasis se correlaciona con una peor respuesta (regresión logística). Conclusiones. Los pacientes con CCFM muestran un perfil psicopatológico con mayores puntuaciones y síntomas que los pacientes sin fibromialgia. Esta diferencia se correlaciona con la respuesta terapéutic

Glibenclamide, metformin, and insulin for the treatment of gestational diabetes : a systematic review and meta-analysis

Objective To summarize short term outcomes in randomized controlled trials comparing glibenclamide or metformin versus insulin or versus each other in women with gestational diabetes requiring drug treatment. Design Systematic review and meta-analysis. Eligibility criteria for selecting studies Randomized controlled trials that fulfilled all the following: (1) published as full text; (2) addressed women with gestational diabetes requiring drug treatment; (3) compared glibenclamide v insulin, metformin v insulin, or metformin v glibenclamide; and (4) provided information on maternal or fetal outcomes. Data sources Medline, CENTRAL, and Embase were searched up to 20 May 2014. Outcomes measures We considered 14 primary outcomes (6 maternal, 8 fetal) and 16 secondary (5 maternal, 11 fetal) outcomes. Results We analyzed 15 articles, including 2509 subjects. Significant differences for primary outcomes in glibenclamide v insulin were obtained in birth weight (mean difference 109 g (95% confidence interval 35.9 to 181)), macrosomia (risk ratio 2.62 (1.35 to 5.08)), and neonatal hypoglycaemia (risk ratio 2.04 (1.30 to 3.20)). In metformin v insulin, significance was reached for maternal weight gain (mean difference −1.14 kg (−2.22 to −0.06)), gestational age at delivery (mean difference −0.16 weeks (−0.30 to −0.02)), and preterm birth (risk ratio 1.50 (1.04 to 2.16)), with a trend for neonatal hypoglycaemia (risk ratio 0.78 (0.60 to 1.01)). In metformin v glibenclamide, significance was reached for maternal weight gain (mean difference −2.06 kg (−3.98 to −0.14)), birth weight (mean difference −209 g (−314 to −104)), macrosomia (risk ratio 0.33 (0.13 to 0.81)), and large for gestational age newborn (risk ratio 0.44 (0.21 to 0.92)). Four secondary outcomes were better for metformin in metformin v insulin, and one was worse for metformin in metformin v glibenclamide. Treatment failure was higher with metformin than with glibenclamide. Conclusions At short term, in women with gestational diabetes requiring drug treatment, glibenclamide is clearly inferior to both insulin and metformin, while metformin (plus insulin when required) performs slightly better than insulin. According to these results, glibenclamide should not be used for the treatment of women with gestational diabetes if insulin or metformin is available. Systematic review registration NCT0199811

Accelerated amyloid deposition, neurofibrillary degeneration and neuronal loss in double mutant APP/tau transgenic mice

Even though the idea that amyloid beta peptide accumulation is the primary event in the pathogenesis of Alzheimer's disease has become the leading hypothesis, the causal link between aberrant amyloid precursor protein processing and tau alterations in this type of dementia remains controversial. We further investigated the role of beta-amyloid production/deposition in tau pathology and neuronal cell death in the mouse brain by crossing Tg2576 and VLW lines expressing human mutant amyloid precursor protein and human mutant tau, respectively. The resulting double transgenic mice showed enhanced amyloid deposition accompanied by neurofibrillary degeneration and overt neuronal loss in selectively vulnerable brain limbic areas. These findings challenge the idea that tau pathology in Alzheimer's disease is merely a downstream effect of amyloid production/deposition and suggest that reciprocal interactions between beta-amyloid and tau alterations may take place in vivo