193 research outputs found

    Monte Carlo uncertainty propagation approaches in ADS burn-up calculations

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    In activation calculations, there are several approaches to quantify uncertainties: deterministic by means of sensitivity analysis, and stochastic by means of Monte Carlo. Here, two different Monte Carlo approaches for nuclear data uncertainty are presented: the first one is the Total Monte Carlo (TMC). The second one is by means of a Monte Carlo sampling of the covariance information included in the nuclear data libraries to propagate these uncertainties throughout the activation calculations. This last approach is what we named Covariance Uncertainty Propagation, CUP. This work presents both approaches and their differences. Also, they are compared by means of an activation calculation, where the cross-section uncertainties of 239Pu and 241Pu are propagated in an ADS activation calculation

    Novel use of plga microspheres to create an animal model of glaucoma with progressive neuroretinal degeneration

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    Progressive degeneration of neuroretinal tissue with maintained elevated intraocular pressure (IOP) to simulate chronic glaucoma was produced by intracameral injections of poly (lactic-co-glycolic) acid (PLGA) microspheres (Ms) in rat eyes. The right eye of 39 rats received different sizes of PLGA-Ms (2 µL suspension; 10% w/v): 14 with 38–20 µm Ms (Ms38/20 model) and 25 with 20–10 µm particles (Ms20/10 model). This novel glaucoma animal model was compared to the episcleral vein sclerosis (EPI) model (25 eyes). Injections were performed at baseline, two, four and six weeks. Clinical signs, IOP, retina and optic nerve thicknesses (using in vivo optical coherence tomography; OCT), and histological studies were performed. An IOP increment was observed in all three groups, however, the values obtained from the PLGA-Ms injection resulted lower with a better preservation of the ocular surface. In fact, the injection of Ms20/10 created a gentler, more progressive, and more sustained increase in IOP. This IOP alteration was correlated with a significant decrease in most OCT parameters and in histological ganglion-cell count for the three conditions throughout the eight-week follow-up. In all cases, progressive degeneration of the retina, retinal ganglion cells and optic nerve, simulating chronic glaucoma, was detected by OCT and corroborated by histological study. Results showed an alternative glaucoma model to the well-known episcleral vein model, which was simpler to perform, more reproducible and easier to monitor in vivo

    Ten years since the introduction of therapeutic hypothermia in neonates with perinatal hypoxic-ischaemic encephalopathy in Spain

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    More than a decade has passed since therapeutic hypothermia (TH) was introduced in Spain; this is the only neuroprotective intervention that has become standard practice in the treatment of perinatal hypoxic-ischaemic encephalopathy (HIE). This article aims to provide a current picture of the technique and to address the controversies surrounding its use. In the last 10 years, TH has been successfully implemented in the vast majority of tertiary hospitals in Spain, and more than 85% of newborns with moderate or severe HIE currently receive the treatment. The factors that can improve the efficacy of TH include early treatment onset (first 6 hours of life) and the control of comorbid factors associated with perinatal asphyxia. In patients with moderate HIE, treatment onset after 6 hours seems to have some neuroprotective efficacy. TH duration longer than 72 hours or deeper hypothermia do not offer greater neuroprotective efficacy, but instead increase the risk of adverse effects. Unclarified aspects are the sedation of patients during TH, the application of the treatment in infants with mild HIE, and its application in other scenarios. Prognostic information and time frame are one of the most challenging aspects. TH is universal in countries with sufficient economic resources, although certain unresolved controversies remain. While the treatment is widespread in Spain, there is a need for cooling devices for the transfer of these patients and their centralisationSe cumple ahora más de una década del inicio de la hipotermia terapéutica (HT) en España, la única intervención neuroprotectora que ha venido a ser práctica estándar en el tratamiento de la encefalopatía hipóxico-isquémica perinatal (EHI). El objetivo de este artículo es ofrecer un panorama actual y presentar las controversias surgidas alrededor de la aplicación de esta terapia. En esta década se ha implantado con éxito la HT en la gran mayoría de los hospitales terciarios de España y más del 85% de los recién nacidos con EHI moderada-grave reciben esta terapia. Entre los aspectos que pueden mejorar la eficacia de la HT están su inicio precoz dentro de las primeras 6 horas de vida y el control de factores comórbidos asociados a la asfixia perinatal. En los pacientes con EHI moderada el inicio después de las 6 horas parece mantener cierta eficacia neuroprotectora. Una duración de la HT mayor de 72 horas o un enfriamiento más profundo no ofrecen mayor eficacia neuroprotectora y aumentan el riesgo de efectos adversos. Persiste la controversia acerca de la sedación durante la HT, la aplicación de esta intervención a los neonatos con EHI leve y en otros escenarios. La información pronóstica y su marco temporal es uno de los aspectos más desafiantes. La HT es universal en países con recursos económicos, aunque existen puntos de controversia no resueltos. Si bien es un tratamiento generalizado en nuestro país, falta disponer de dispositivos para el traslado de estos pacientes y su centralizació

    Chronic glaucoma using biodegradable microspheres to induce intraocular pressure elevation. Six-month follow-up

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    Background: To compare two prolonged animal models of glaucoma over 24 weeks of follow-up. A novel pre-trabecular model of chronic glaucoma was achieved by injection of biodegradable poly lactic-co-glycolic acid (PLGA) microspheres (10–20 µm) (Ms20/10) into the ocular anterior chamber to progressively increase ocular hypertension (OHT). Methods: Rat right eyes were injected to induce OHT: 50% received a suspension of Ms20/10 in the anterior chamber at 0, 2, 4, 8, 12, 16 and 20 weeks, and the other 50% received a sclerosing episcleral vein injection biweekly (EPIm). Ophthalmological clinical signs, intraocular pressure (IOP), neuroretinal functionality measured by electroretinography (ERG), and structural analysis of the retina, retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL) protocols using optical coherence tomography (OCT) and histological exams were performed. Results: Both models showed progressive neuroretinal degeneration (p < 0.05), and contralateral eye affectation. The Ms20/10 model showed a more progressive increase in IOP and better preservation of ocular surface. Although no statistical differences were found between models, the EPIm showed a tendency to produce thicker retinal and thinner GCL thicknesses, slower latency and smaller amplitude as measured using ERG, and more aggressive disturbances in retinal histology. In both models, while the GCL showed the greatest percentage loss of thickness, the RNFL showed the greatest and earliest rate of thickness loss. Conclusions: The intracameral model with biodegradable microspheres resulted more like the conditions observed in humans. It was obtained by a less-aggressive mechanism, which allows for adequate study of the pathology over longer periods. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

    Influence of chronic ocular hypertension on emmetropia: Refractive, structural and functional study in two rat models

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    Chronic ocular hypertension (OHT) influences on refraction in youth and causes glaucoma in adulthood. However, the origin of the responsible mechanism is unclear. This study analyzes the effect of mild-moderate chronic OHT on refraction and neuroretina (structure and function) in young-adult Long-Evans rats using optical coherence tomography and electroretinography over 24 weeks. Data from 260 eyes were retrospectively analyzed in two cohorts: an ocular normotension (ONT) cohort (20 mmHg), in which OHT was induced either by sclerosing the episcleral veins (ES group) or by injecting microspheres into the anterior chamber. A trend toward emmetropia was found in both cohorts over time, though it was more pronounced in the OHT cohort (p < 0.001), especially in the ES group (p = 0.001) and males. IOP and refraction were negatively correlated at week 24 (p = 0.010). The OHT cohort showed early thickening in outer retinal sectors (p < 0.050) and the retinal nerve fiber layer, which later thinned. Electroretinography demonstrated early supranormal amplitudes and faster latencies that later declined. Chronic OHT accelerates emmetropia in Long–Evans rat eyes towards slowly progressive myopia, with an initial increase in structure and function that reversed over time. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

    5G Visualization: The METIS-II Project Approach

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    [EN] One of the main objectives of the METIS-II project was to enable 5G concepts to reach and convince a wide audience from technology experts to decision makers from non-ICT industries. To achieve this objective, it was necessary to provide easy-to-understand and insightful visualization of 5G. This paper presents the visualization platform developed in the METIS-II project as a joint work of researchers and artists, which is a 3D visualization tool that allows viewers to interact with 5G-enabled scenarios, while permitting simulation driven data to be intuitively evaluated. The platform is a game-based customizable tool that allows a rapid integration of new concepts, allows real-time interaction with remote 5G simulators, and provides a virtual reality-based immersive user experience. As a result, the METIS-II visualization platform has successfully contributed to the dissemination of 5G in different fora and its use will be continued after METIS-II.This work has been performed in the framework of the H2020/5G-PPP project METIS-II cofunded by the EU. The authors wish to thank the rest of METIS-II colleagues who contributed to the development of the METIS-II visualization platform.Martín-Sacristán, D.; Herranz Claveras, C.; Monserrat Del Río, JF.; Szczygiel, A.; Kuruvatti, NP.; Garcia-Roger, D.; Prado-Alvarez, D.... (2018). 5G Visualization: The METIS-II Project Approach. Mobile Information Systems. 1-8. https://doi.org/10.1155/2018/2084950S18Zyda, M. (2005). From visual simulation to virtual reality to games. Computer, 38(9), 25-32. doi:10.1109/mc.2005.297Johnson, C. (2004). Top scientific visualization research problems. IEEE Computer Graphics and Applications, 24(4), 13-17. doi:10.1109/mcg.2004.20Tullberg, H., Popovski, P., Li, Z., Uusitalo, M. A., Hoglund, A., Bulakci, O., … Monserrat, J. F. (2016). The METIS 5G System Concept: Meeting the 5G Requirements. IEEE Communications Magazine, 54(12), 132-139. doi:10.1109/mcom.2016.1500799cmLee, B., Riche, N. H., Isenberg, P., & Carpendale, S. (2015). More Than Telling a Story: Transforming Data into Visually Shared Stories. IEEE Computer Graphics and Applications, 35(5), 84-90. doi:10.1109/mcg.2015.99Yi, J. S., Kang, Y. ah, & Stasko, J. (2007). Toward a Deeper Understanding of the Role of Interaction in Information Visualization. IEEE Transactions on Visualization and Computer Graphics, 13(6), 1224-1231. doi:10.1109/tvcg.2007.70515Campbell, B. D. (2016). Immersive Visualization to Support Scientific Insight. IEEE Computer Graphics and Applications, 36(3), 17-21. doi:10.1109/mcg.2016.6

    Exportation of MDR TB to europe from setting with actively transmitted persistent strains in peru

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    We performed a cross-border molecular epidemiology analysis of multidrug-resistant tuberculosis in Peru, Spain, and Italy. This analysis revealed frequent transmission in Peru and exportation of a strain that recreated similar levels of transmission in Europe during 2007–2017. Transnational efforts are needed to control transmission of multidrug-resistant tuberculosis globally
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