Spin reorientation transition of magnetite (001)

We have imaged the rearrangement of the magnetic domains on magnetite (001) when crossing the spin reorientation transition and the Verwey transition with nanometer resolution. By means of spin-polarized low-energy electron microscopy we have monitored the change in the easy axes lowering the temperature through both transitions in remanence. The spin reorientation transition occurs in two steps: initial nucleation and growth of domains with a new surface magnetic orientation is followed by a smooth evolution.We thank Dr. A. T. N'Diaye for his support with the scripts for the color representation of the magnetization. This research was partly supported by the Spanish Ministry of Economy and Competitiveness (MINECO) under Projects No. MAT2011-52477-C5-2-P, No. MAT2012-38045-C04-01, and No. MAT2015-64110-C2-1-P. G.S.P. and R.B. acknowledge funding from the Austrian Science Fund START prize Y 847-N20 and Project No. P24925-N20. Experiments were performed at the Molecular Foundry, Lawrence Berkeley National Laboratory, supported by the Office of Science, Office of Basic Energy Sciences, Scientific User Facilities Division, of the U. S. Department of Energy under Contract No. DE-AC02-05CH11231. L.M.-G. thanks the MINECO for an FPI contract with reference Contract No. BES-2013-063396. R.B. acknowledges a stipend from the TU Wien and Austrian Science Fund doctoral college Solids4Fun (Project No. W1243). A.M. thanks the support of the Spanish Ministry of Education through Project No. PRX14/00307.Peer Reviewe

Memory effect and magnetocrystalline anisotropy impact on the surface magnetic domains of magnetite(001)

The structure of magnetic domains, i.e. regions of uniform magnetization separated by domain walls, depends on the balance of competing interactions present in ferromagnetic (or ferrimagnetic) materials. When these interactions change then domain configurations also change as a result. Magnetite provides a good test bench to study these effects, as its magnetocrystalline anisotropy varies significantly with temperature. Using spin-polarized electron microscopy to map the micromagnetic domain structure in the (001) surface of a macroscopic magnetite crystal (similar to 1 cm size) shows complex domain patterns with characteristic length-scales in the micrometer range and highly temperature dependent domain geometries. Although heating above the Curie temperature erases the domain patterns completely, cooling down reproduces domain patterns not only in terms of general characteristics: instead, complex microscopic domain geometries are reproduced in almost perfect fidelity between heating cycles. A possible explanation of the origin of the high-fidelity reproducibility is suggested to be a combination of the presence of hematite inclusions that lock bulk domains, together with the strong effect of the first order magnetocrystalline anisotropy which competes with the shape anisotropy to give rise to the observed complex patterns

Formation of titanium monoxide (001) single-crystalline thin film induced by ion bombardment of titanium dioxide (110)

© 2015 Macmillan Publishers Limited. All rights reserved. A plethora of technological applications justify why titanium dioxide is probably the most studied oxide, and an optimal exploitation of its properties quite frequently requires a controlled modification of the surface. Low-energy ion bombardment is one of the most extended techniques for this purpose and has been recently used in titanium oxides, among other applications, to favour resistive switching mechanisms or to form transparent conductive layers. Surfaces modified in this way are frequently described as reduced and defective, with a high density of oxygen vacancies. Here we show, at variance with this view, that high ion doses on rutile titanium dioxide (110) induce its transformation into a nanometric and single-crystalline titanium monoxide (001) thin film with rocksalt structure. The discovery of this ability may pave the way to new technical applications of ion bombardment not previously reported, which can be used to fabricate heterostructures and interfaces.Peer Reviewe

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Depto. de Teorías y Análisis de la ComunicaciónFac. de Ciencias de la InformaciónFALSEsubmitte

Enfermedades crónicas

Adherencia al tratamiento farmacológico y relación con el control metabólico en pacientes con DM2Aluminio en pacientes con terapia de reemplazo renal crónico con hemodiálisis en Bogotá, ColombiaAmputación de extremidades inferiores: ¿están aumentando las tasas?Consumo de edulcorantes artificiales en jóvenes universitariosCómo crecen niños normales de 2 años que son sobrepeso a los 7 añosDiagnóstico con enfoque territorial de salud cardiovascular en la Región MetropolitanaEfecto a corto plazo de una intervención con ejercicio físico, en niños con sobrepesoEfectos de la cirugía bariátrica en pacientes con síndrome metabólico e IMC < 35 KG/M2Encuesta mundial de tabaquismo en estudiantes de profesiones de saludEnfermedades crónicas no transmisibles: Consecuencias sociales-sanitarias de comunidades rurales en ChileEpidemiología de las muertes hospitalarias por patologías relacionadas a muerte encefálica, Chile 2003-2007Estado nutricional y conductas alimentarias en adolescentes de 4º medio de la Región de CoquimboEstudio de calidad de vida en una muestra del plan piloto para hepatitis CEvaluación del proceso asistencial y de resultados de salud del GES de diabetes mellitus 2Factores de riesgo cardiovascular en población universitaria de la Facsal, universidad de TarapacáImplicancias psicosociales en la génesis, evolución y tratamiento de pacientes con hipertensión arterial esencialInfarto agudo al miocardio (IAM): Realidad en el Hospital de Puerto Natales, 2009-2010Introducción de nuevas TIC y mejoría de la asistencia a un programa de saludNiños obesos atendidos en el Cesfam de Puerto Natales y su entorno familiarPerfil de la mortalidad por cáncer de cuello uterino en Río de JaneiroPerfil del paciente primo-consultante del Programa de Salud Cardiovascular, Consultorio Cordillera Andina, Los AndesPrevalencia de automedicación en mujeres beneficiarias del Hospital Comunitario de Til-TiPrevalencia de caries en población preescolar y su relación con malnutrición por excesoPrevalencia de retinopatía diabética en comunas dependientes del Servicio de Salud Metropolitano Occidente (SSMOC)Problemas de adherencia farmacológica antihipertensiva en población mapuche: Un estudio cualitativoRol biológico de los antioxidantes innatos en pacientes portadores de VIH/SidaSobrepeso en empleados de un restaurante de una universidad pública del estado de São Paul

Influence of the ZrO2 Crystalline Phases on the Nature ofActive Sites in PdCu/ZrO2 Catalysts for the Methanol Steam Reforming Reaction—An In Situ Spectroscopic Study

In this work, the electronic properties of the metal sites in cubic and monoclinic ZrO2 supported Pd and PdCu catalysts have been investigated using CO as probe molecule in in-situ IR studies, and the surface composition of the outermost layers has been studied by APXPS (Ambient Pressure X-ray Photoemission Spectroscopy). The reaction products were followed by mass spectrometry, making it possible to relate the chemical properties of the catalysts under reaction conditions with their selectivity. Combining these techniques, it has been shown that the structure of the support (monoclinic or cubic ZrO2) affects the metal dispersion, mobility, and reorganization of metal sites under methanol steam reforming (MSR) conditions, influencing the oxidation state of surface metal species, with important consequences in the catalytic activity. Correlating the mass spectra of the reaction products with these spectroscopic studies, it was possible to conclude that electropositive metal species play an imperative role for high CO2 and H2 selectivity in the MSR reaction (less CO formation)The research leading to these results has received funding from European Research council project SYNCATMATCH (671093) and from Spanish Ministry of Science, Innovation and Universities with the project “I + D + I research challenges (RTI2018-099668-B-C21)”. This work also was financially supported by: Base Funding-UIDB/00511/2020 of the Laboratory for Process Engineering, Environment, Biotechnology and Energy—LEPABE-funded by national funds through the FCT/MCTES (PIDDAC); European Union’s Seventh Framework Program (FP/2007-2013) for the Fuel Cells and Hydrogen Joint Technology Initiative under grant agreement no. 303476.Peer reviewe

Memory effect and magnetocrystalline anisotropy impact on the surface magnetic domains of magnetite(001).

The structure of magnetic domains, i.e. regions of uniform magnetization separated by domain walls, depends on the balance of competing interactions present in ferromagnetic (or ferrimagnetic) materials. When these interactions change then domain configurations also change as a result. Magnetite provides a good test bench to study these effects, as its magnetocrystalline anisotropy varies significantly with temperature. Using spin-polarized electron microscopy to map the micromagnetic domain structure in the (001) surface of a macroscopic magnetite crystal (~1 cm size) shows complex domain patterns with characteristic length-scales in the micrometer range and highly temperature dependent domain geometries. Although heating above the Curie temperature erases the domain patterns completely, cooling down reproduces domain patterns not only in terms of general characteristics: instead, complex microscopic domain geometries are reproduced in almost perfect fidelity between heating cycles. A possible explanation of the origin of the high-fidelity reproducibility is suggested to be a combination of the presence of hematite inclusions that lock bulk domains, together with the strong effect of the first order magnetocrystalline anisotropy which competes with the shape anisotropy to give rise to the observed complex patterns

Formation of titanium monoxide (001) single-crystalline thin film induced by ion bombardment of titanium dioxide (110)

A plethora of technological applications justify why titanium dioxide is probably the most studied oxide, and an optimal exploitation of its properties quite frequently requires a controlled modification of the surface. Low-energy ion bombardment is one of the most extended techniques for this purpose and has been recently used in titanium oxides, among other applications, to favour resistive switching mechanisms or to form transparent conductive layers. Surfaces modified in this way are frequently described as reduced and defective, with a high density of oxygen vacancies. Here we show, at variance with this view, that high ion doses on rutile titanium dioxide (110) induce its transformation into a nanometric and single-crystalline titanium monoxide (001) thin film with rocksalt structure. The discovery of this ability may pave the way to new technical applications of ion bombardment not previously reported, which can be used to fabricate heterostructures and interfaces

Exploration of meanings regarding oral health in a group of pregnant women in Medellin, Colombia. Is there oral health literacy?

ABSTRACT: In many cultures, mothers are responsible for taking care of their babies, being the mother frequently the most significant adult, a model to follow, and the principal transmitter of culture, including health knowledge and practices. The objective of this study was to explore a group of pregnant women’s perceptions of their own oral health and that of their children. These women were all from Medellín, Colombia, and they were participating in one of the city’s intervention programs. Methods: An ethno-methodological approach was used; therefore, semi-structured interviews were conducted, recorded, transcribed and analyzed, and the responses were classified according to four criteria: recurrence, divergence, tendencies, and significant meanings. Results: pregnant mothers give significant importance to the mouth due to survival and esthetic reasons. They emphasize teeth over other parts of the mouth and think that oral health is synonymous to healthy teeth. The concept of oral hygiene is represented as cleaning the teeth with toothbrush and toothpaste. The mouth of their future child is not a matter of concern, and they consider oral hygiene important but not in early stages. Conclusions: the interviewed mothers recognize the mouth as an essential survival element. Care of the baby’s mouth gains importance as teeth appear. Dental floss, which is considered necessary as a cleaning element, is not used by pregnant women, not is it frequent tooth brushing. The claim of Oral Health Literacy is to build knowledge in order to promote and preserve health.RESUMEN: En muchas culturas, la madre es la responsable por excelencia del cuidado del bebé, en muchos casos el adulto más significativo, modelo de referencia imitable y transmisora principal de cultura, incluyendo conocimientos y prácticas de salud. El objetivo fue explorar en un grupo de gestantes de la ciudad de Medellín participantes de un programa de intervención, los significados con respecto a la salud bucal propia y de sus hijos. Métodos: el abordaje metodológico fue la etnometodología; se aplicaron entrevistas semiestructuradas que fueron grabadas, transcritas y analizadas, agrupando las respuestas en recurrencias, divergencias, textos significativos y tendencias. Resultados: las gestantes otorgan un significado importante a la boca, relacionado con la supervivencia y la estética; enfatizan en los dientes como parte integrante de la boca y consideran la salud bucal sinónimo de dientes sanos. El concepto de higiene bucal lo representan como higiene de los dientes, con cepillo y crema dental. La boca de su futuro hijo no es asunto de preocupación, aunque consideran importante su higiene, pero no en etapas tempranas. Conclusiones: la boca como elemento fundamental de supervivencia, es un asunto reconocido por las entrevistadas. Los cuidados de la boca del bebé, adquieren importancia en relación con la aparición de los dientes. La seda dental, elemento necesario para la higiene de los dientes, no está incorporado en las prácticas de las gestantes, como tampoco una frecuencia del cepillado. La alfabetización en salud propone construir conocimiento que incida positivamente en el fomento y conservación de la salud.Empresa Colgate y la Universidad de Antioqui