2,992 research outputs found

    Impact of activation cross-section uncertainties on the tritium production in the HFTM specimen cells

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    The prediction of the tritium production is required for handling procedures of samples, safety & maintenance and licensing of the International Fusion Materials Irradiation Facility (IFMIF). A comparison of the evaluated tritium production cross-sections with available experimental data from the EXFOR data base has shown insufficient validation. And significant discrepancies in evaluated cross-section libraries, including lack of tritium production reactions for some important elements, were found. Here, we have addressed an uncertainty analysis to draw conclusions on the reliability of the tritium prediction under the potential impact of activation cross-section uncertainties. We conclude that there is not sufficient experimental validation of the evaluated tritium production cross-sections, especially for iron and sodium. Therefore a dedicated experimental validation program for those elements should be desirable

    Supervivencia de circuitos de técnicas de depuración extrarrenal continua en pacientes críticos con o sin anticoagulación convencional: estudio observacional prospectivo

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    Fundamento. El objetivo del presente estudio es describir la eficacia, seguridad y viabilidad, en pacientes críticos con técnica de depuración extrarrenal continua (TDEC) y diferente riesgo de hemorragia, de un sistema de anticoagulación convencional con perfusión continua de heparina no fraccionada (HNF) frente a no anticoagular usando lavados son suero fisiológico. Material y métodos. Se trata de un estudio observacional prospectivo realizado en la Unidad de Cuidados Intensivos (UCI) desde octubre de 2013 hasta abril de 2016. Se incluyeron 61 pacientes que presentaron insuficiencia renal aguda (IRA) con requerimientos de TDEC y un total de 122 circuitos. Tanto los pacientes como los circuitos fueron divididos para su análisis en dos grupos: anticoagulados (AC) y no anticoagulados (No AC). La variable principal fue la supervivencia de los circuitos. Además se recogieron diferentes parámetros analíticos al comienzo del tratamiento y en el momento de coagulación del circuito. Resultados. La distribución de pacientes anticoagulados y no anticoagulados fue similar. No se han encontrado diferencias significativas en la supervivencia de los circuitos entre ambos grupos (30,5 horas AC vs 34,9 horas No AC). Los pacientes con mayor morbilidad (trombopenia severa, coagulopatía, etc.) pertenecían al grupo que no recibió anticoagulación, sino lavados con suero fisiológico. Conclusiones. En pacientes críticos con alto riesgo de sangrado las TDEC son viables sin anticoagulación más el empleo de lavados periódicos con suero fisiológico se comporta como una medida viable, segura y eficaz obteniendo una supervivencia de los circuitos similar a la de pacientes anticoagulados con HNF, evitando los riesgos y costes asociados a la anticoagulación.Background. The aim of this study was to describe the efficacy, security and viability of an anticoagulation system with continuous infusion of unfractionated heparin (UFH) versus one without any type of anticoagulant using 0.9% physiological saline washings, in critically ill patients with continuous renal replacement therapy (CRRT) and different risks of bleeding. Methods. From October 2013 to April 2015 we conducted an observational prospective study in the intensive care unit (ICU). Sixty-one patients with acute kidney injury (AKI) and requiring CRRT were included, with 122 filters. Patients and filters were divided in two groups: anticoagulated (AC) and not anticoagulated (No AC). The main outcome measure was filter life span. Different analytical parameters were also collected at the beginning of treatment and at the moment of circuit coagulation Results. The number of patients was similar in both groups. We did not find statistically significant differences between the two groups in filter life span (30.5 hours AC vs 34.9 hours No AC). Patients with increased morbidity (severe thrombocytopenia, coagulopathy, etc.) were included in the group that did not received anticoagulation but saline flushes. Conclusions. CRRT without anticoagulation with saline flushes is a viable, safe and effective strategy in critically ill patients with high risk of bleeding. This approach achieves a circuit life span similar to that observed in anticoagulated patients with UFH; avoiding the risks and costs associated with anticoagulation

    Inherited photoreceptor degeneration causes the death of melanopsin-positive retinal ganglion cells and increases their coexpression of brn3a

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    Purpose: To study the population of intrinsically photosensitive retinal ganglion cells (melanopsin-expressing RGCs, m+RGCs) in P23H-1 rats, a rat model of inherited photoreceptor degeneration. Methods: At postnatal (P) times P30, P365, and P540, retinas from P23H dystrophic rats (line 1, rapid degeneration; and line 3, slow degeneration) and Sprague Dawley (SD) rats (control) were dissected as whole-mounts and immunodetected for melanopsin and/or Brn3a. The dendritic arborization of m+RGCs and the numbers of Brn3a+RGCs and m+RGCs were quantified and their retinal distribution and coexpression analyzed. Results: In SD rats, aging did not affect the population of Brn3a+RGCs or m+RGCs or the percentage that showed coexpression (0.27%). Young P23H-1 rats had a significantly lower number of Brn3a+RGCs and showed a further decline with age. The population of m+RGCs in young P23H-1 rats was similar to that found in SD rats and decreased by 22.6% and 28.2% at P365 and P540, respectively, similarly to the decrease of the Brn3a+RGCs. At these ages the m+RGCs showed a decrease of their dendritic arborization parameters, which was similar in both the P23H-1 and P23H-3 lines. The percentage of coexpression of Brn3a was, however, already significantly higher at P30 (3.31%) and increased significantly with age (10.65% at P540). Conclusions: Inherited photoreceptor degeneration was followed by secondary loss of Brn3a+RGCs and m+RGCs. Surviving m+RGCs showed decreased dendritic arborization parameters and increased coexpression of Brn3a and melanopsin, phenotypic and molecular changes that may represent an effort to resist degeneration and/or preferential survival of m+RGCs capable of synthesizing Brn3a

    Serial optical coherence microscopy for label-free volumetric histopathology

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    The observation of histopathology using optical microscope is an essential procedure for examination of tissue biopsies or surgically excised specimens in biological and clinical laboratories. However, slide-based microscopic pathology is not suitable for visualizing the large-scale tissue and native 3D organ structure due to its sampling limitation and shallow imaging depth. Here, we demonstrate serial optical coherence microscopy (SOCM) technique that offers label-free, high-throughput, and large-volume imaging of ex vivo mouse organs. A 3D histopathology of whole mouse brain and kidney including blood vessel structure is reconstructed by deep tissue optical imaging in serial sectioning techniques. Our results demonstrate that SOCM has unique advantages as it can visualize both native 3D structures and quantitative regional volume without introduction of any contrast agents

    The "Solar Model Problem" Solved by the Abundance of Neon in Stars of the Local Cosmos

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    The interior structure of the Sun can be studied with great accuracy using observations of its oscillations, similar to seismology of the Earth. Precise agreement between helioseismological measurements and predictions of theoretical solar models has been a triumph of modern astrophysics (Bahcall et al. 2005). However, a recent downward revision by 25-35% of the solar abundances of light elements such as C, N, O and Ne (Asplund et al. 2004) has broken this accordance: models adopting the new abundances incorrectly predict the depth of the convection zone, the depth profiles of sound speed and density, and the helium abundance (Basu Antia 2004, Bahcall et al. 2005). The discrepancies are far beyond the uncertainties in either the data or the model predictions (Bahcall et al. 2005b). Here we report on neon abundances relative to oxygen measured in a sample of nearby solar-like stars from their X-ray spectra. They are all very similar and substantially larger than the recently revised solar value. The neon abundance in the Sun is quite poorly determined. If the Ne/O abundance in these stars is adopted for the Sun the models are brought back into agreement with helioseismology measurements (Antia Basu 2005, Bahcall et al. 2005c).Comment: 13 pages, 3 Figure
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