2,516 research outputs found

    Phase prediction, microstructure and high hardness of novel light-weight high entropy alloys

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    Guided by CALPHAD modeling, low-density and multiphase three novel High Entropy Alloys (HEAs), Al40Cu15Cr15Fe15Si15, Al65Cu5Cr5Si15Mn5Ti5 and Al60Cu10Fe10Cr5Mn5Ni5Mg5 were produced by large scale vacuum die casting. A mixture of simple and complex phases was observed in the as-cast microstructures, which demonstrates good agreement with CALPHAD results. The measured densities varied from 3.7 g/cm3 to 4.6 g/cm3 and microhardness from 743 Hv to 916 Hv. Finally, the hardness of all the light-weight HEAs (LWHEAs) with densities below 4.6 g/cm3 manufactured to date were reviewed. The hardness of Al40Cu15Cr15Fe15Si15 and hardness to density ratio of Al65Cu5Cr5Si15Mn5Ti5 are the highest of all LWHEAs reported up to date.This work has been partially funded by the Basque government through the Project Elkartek: KK-2017/0000

    Nivel de conocimiento y cumplimiento de medidas de protección personal en enfermeras del Servicio de Cirugía del Hospital Belén de Trujillo, 2016

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    La investigación se realizó con el propósito de determinar la relación que existe entre el nivel de conocimiento y cumplimiento de medidas de protección personal en enfermeras del servicio de cirugía del Hospital Belén de Trujillo, 2016. El tipo de estudio fue descriptivo correlacional, de corte transversal, el universo muestral estuvo constituido por 22 enfermeras. Se aplicó dos instrumentos, el primero para identificar el nivel de conocimiento sobre medidas de protección personal y el segundo para valorar el cumplimiento de medidas de protección personal. Los resultados evidenciaron que: El 54.55% de enfermeras obtuvieron nivel de conocimiento alto, el 44.45% nivel medio y no se encontró nivel bajo de conocimiento. El 81.82 % de las enfermeras si cumplen con las medidas de protección personal y el 18.18% no cumplen. Aplicando la prueba estadística Chi- cuadrado, se obtuvo como valor p < 0.05; concluyendo que existe una relación de significancia entre ambas variables.This research conducted in order to determine the relationship between the level of knowledge and compliance measures for personal protection surgery services nurses at Belén Hospital of Trujillo, 2016. The type of study was correlational descriptive, cutting cross, the sample universe consisted of 22 nurses. Two instruments were applied, the first to identify the level of knowledge about measures and the second to assess compliance with personal protective measures. The results showed that: The 54.55% of nurses obtained high-level knowledge, 44.45% average level and low level of knowledge not found. The 81.82% of the nurses if they meet the personal protection measures and 18.18% do not comply. Applying the Chi- square, was obtained as a value p < 0.05; concluding that there is a significant relationship between the two variables

    Compound Formation and Microstructure of As-Cast High Entropy Aluminums

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    The aim of this work is to study the microstructure of four high entropy alloys (HEAs) produced by large scale vacuum die casting. Al40Cu15Mn5Ni5Si20Zn15, Al45Cu15Mn5Fe5Si5Ti5Zn20, Al35Cu5Fe5Mn5Si30V10Zr10, and Al50Ca5Cu5Ni10Si20Ti10 alloys formed a mixture of different structures, containing intermetallic compound (IC) and solid solution (SS) phases. The phases observed in the casting alloys were compared with the equilibrium phases predicted by Thermo-Calc. The measured densities varied from 3.33 g/cm−3 to 5.07 g/cm−3 and microhardness from 437 Hv to 887 Hv. Thus, the microhardness and estimated strength/density ratios are significantly higher than other lightweight high entropy alloys (LWHEAs).This work has been partially funded by the Basque Government through the project Elkartek: KK-2017/00007

    Diachronism in the late Neoproterozoic–Cambrian arc-rift transition of North Gondwana: a comparison of Morocco and the Iberian Ossa-Morena Zone

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    In the northwestern border of the West African craton (North Gondwana), a transition from late Neoproterozoic subduction/collision to Cambrian rift processes was recorded in the Anti-Atlas (Morocco) and in the Ossa-Morena Zone (Iberia). Cambrian rifting affected both Pan-African and Cadomian basements in a stepwise and diachronous way. Subsequently, both areas evolved into a syn-rift margin episodically punctuated by uplift and tilting that precluded Furongian sedimentation. A comparison of sedimentary, volcanic and geodynamic evolution is made in the late Neoproterozoic (Pan-African and Cadomian) belts and Cambrian rifts trying to solve the apparent diachronous (SW–NE-trending) propagation of an early Palaeozoic rifting regime that finally led to the opening of the Rheic Ocean

    Cancer Stem Cells as a Result of a Reprogramming-Like Mechanism

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    Open Access: under CC BY-NCSA 3.0 license.Research in our groups is partially supported by FEDER and by MICINN (SAF2009-08803 to ISG), by Junta de Castilla y León (Proyecto Biomedicina 2009-2010 to ISG, and Proyecto Biomedicina 2010-2011 to CVD), by MEC OncoBIO Consolider-Ingenio 2010 (Ref. CSD2007- 0017) to ISG, by NIH grant (R01 CA109335-04A1) to ISG, by Sandra Ibarra Foundation to ISG, and by Group of Excellence Grant (GR15) from Junta de Castilla y Leon to ISG and JJC.Peer reviewe

    Intra-crustal recycling and crustal-mantle interactions in

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    In situ O-isotope compositions of detrital, inherited and melt-precipitated zircons with Neoproterozoic to Ordovician ages are presented to assess the crustal evolution of the North Gondwana margin. Different groups of pre-Mesozoic rocks from SW Iberia were targeted: i) Ediacaran paragneisses and meta-greywakes of the Ossa-Morena Zone – the Serie Negra Group deposited at ~ 560 Ma in a Cadomian magmatic arc setting (Pereira et al., 2008); ii) Early to Middle Cambrian orthogneisses and volcaniclastic rocks of the Ossa-Morena Zone – Evora Massif igneous complexes related to ensialic rifting at ~ 530–500 Ma (Pereira et al., 2008, Chichorro et al., 2008); iii) Late Cambrian to Early Ordovician volcaniclastic rocks and granites of the Ossa-Morena–Central Iberian transition zone – the Urra Formation and Portalegre granite formed at ~ 495– 488 Ma in a extensional setting (Solá et al., 2008); iv) Carboniferous granitoids (Nisa and Arraiolos granites) containing inherited zircons with Cambrian to Ordovician ages (Solá, this volume). A compilation the results for the period ~ 3.4 Ga to ~ 450 Ma reveals that: a) Archean zircons show little variation in d18O, with most values lying between 4.7 and 7.5‰, (average 6.2‰) comparable with usual d18O of zircons from Archean elsewhere (e.g., Valley et al., 2005); b) the range of d18O in Paleoproterozoic grains increases between 2.1 and 1.8 Ga with d18O >7.5‰, indicating increasing supracrustal recycling, but at ~ 1.8 Ga the d18O has mantle-like values (<5.1‰), documenting a crustal growth episode at this time; c) rare Mesoproterozoic grains have mildly evolved d18O values in the range 5.6–7.1‰); d) Tonian grains have low d18O values (4.2–5.6‰) typical of mantle-derived juvenile magmas but also higher values of 9.9‰ suggesting intra-crustal recycling; e) Cryogenian–Ordovician zircons show more variable and higher d18O values (~4 to >10‰), indicating great diversity and mixing of sources through intra-crustal recycling and crust–mantle interactions; f) some d18O values near to or below mantle composition (5.3 ± 0.3‰) were recorded at ~ 590 Ma (Ediacaran) suggesting input of mantle material into the crust; g) a decrease in variance of d18O occurs from 575 Ma to the Ediacaran/Cambrian boundary, suggesting a relative decrease in the magmatic contribution of surface-derived material; h) in Cambrian times, the average d18O is higher in the 536–520Ma interval (7.0‰) than in the 520–488 interval (6.2‰), which can be taken as a signal of gradual opening of the system to mantle-derived, mafic, rift-related igneous complexes; i) higher values of d18O (>7.5 ‰) recorded at ~ 623–574 Ma and 490–470Ma mark periods of pronounced increase in crustal recycling

    Rift-related volcanism predating the birth of the Rheic Ocean

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    Two very different periods of magma emplacement in the crust of the Ossa-Morena zone (early and main events) in SW Iberia have been previously interpreted to record a Cambrian/Early Ordovician rifting event that is thought to have culminated in the opening of the Rheic Ocean during the Early Ordovician. New stratigraphic, petrographic, geochemical and Sm–Nd isotope data from Cambrian volcanic rocks included in six key low-grade sections in both Portugal and Spain considerably improve our understanding of these events. These data: (1) confirm the existence of two rift-related magmatic events in the Cambrian of the Ossa-Morena zone, (2) demonstrate that the early rift-related event was associated with migmatite and core-complex formation in the mid-upper crust and is represented by felsic peraluminous rocks, the parent magmas of which were derived mainly from crustal sources, and (3) show the main rift-related event to be represented by a bimodal association of felsic and mafic rocks with minor amounts of intermediate rocks. Some of the mafic rocks show N-MORB affinity, whereas others have OIB or E-MORB affinities, suggesting different heterogeneous mantle sources (depleted and enriched, asthenospheric and lithospheric, plume-like and non-plume-like). The acid and intermediate rocks appear to represent hybrid mixtures of crust and mantle-derived magmas. This new data supports the hypothesis that the onset of rifting was associated with a process of oblique ridgetrench collision. We interpret the significant differences between the early and main events as reflecting the evolution froma wide rift stagewith passive extensionmainly accommodated by lower-crust flowin a high heatflow setting, to a narrow rift stage with active extension characterized by extension rates that outpaced thermal diffusion rates

    Exploring the antigenic relatedness of influenza virus haemagglutinins with strain-specific polyclonal antibodies

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    Alternative methods to the standard haemagglutination inhibition (HI) and neutralization tests to probe the antigenic properties of the influenza virus haemagglutinin (HA) were developed in this study. Vaccinia virus recombinants expressing reference HAs were used to immunize rabbits from which polyclonal antibodies were obtained. These antibodies were subtype specific but showed limited intra-subtype strain specificity in ELISA. The discriminatory capacity of these antibodies was, however, markedly increased after adsorption to cells infected with heterologous influenza viruses, revealing antigenic differences that were otherwise undistinguishable by standard HI and neutralization tests. Furthermore, the unadsorbed antibodies could be used to select escape mutants of the reference strain, which after sequencing unveiled amino acid changes responsible of the noted antigenic differences. These procedures therefore provide alternative methods for the antigenic characterization of influenza HA and might be useful in studies of HA antigenic evolution.This work was supported by grants (JAM) GR09/0039, (IC) GR09/0040 and (JAM) SAF2012-31217.S
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