2,516 research outputs found
Phase prediction, microstructure and high hardness of novel light-weight high entropy alloys
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
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
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
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
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
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
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
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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