Spinodally synthesized magnetoelectric

This is the publisher's version, also available electronically from http://scitation.aip.org/content/aip/journal/apl/91/8/10.1063/1.2767174.Lead zirconium titanate/nickel ferrite (PZT/NFO) composites have been produced by crystallizing and spinodally decomposing a gel in a magnetic field below the Curie temperature of NFO. The gel had been formed by spinning a sol onto a silicon substrate. The ensuing microstructure, characterized by atomic force microscopy, magnetic force microscopy, (Lorentz) transmission electron microscopy, and scanning electron microscopy, is nanoscopically periodic and, determined by the direction of magnetic annealing field, anisotropic. The wavelength of the PZT/NFO alternation, 25nm, agrees within a factor of 2 with the theoretically estimated value. The macroscopic ferromagnetic and magnetoelectric responses correspond qualitatively and semiquantitatively to the features of the nanostructure. The maximum of the field dependent magnetoelectric susceptibility equals 1.8V∕cmOe

Non-volatility of ferroelectric SBT thin fims, at 75ºC

[ES] El estudio de la no volatilidad de una memoria FeRAM de tantalato de bismuto y estroncio, SrBi2Ta2O9 (SBT) en condiciones reales de uso, requiere la caracterización ferroeléctrica del material en forma de lámina delgada a temperaturas por encima del ambiente. Para ello se han depositado láminas de SBT mediante un método sol-gel, sobre substratos de Pt/TiO2/SiO2/Si(100), seleccionándose condensadores de área 5.10-4 cm-2. Basándonos en las medidas de la variación de la polarización con el tiempo (retención) realizadas a temperatura ambiente y a 75ºC, analizamos la viabilidad del material como una FeRAM en condiciones reales de uso.[EN] The study of the non-volatility of Strontium bismuth tantalate SrBi2Ta2O9 (SBT) FeRAM memory, at real operating conditions, requires the ferroelectric characterisation of the material, as a thin film, above the room temperature.As a result, it has been deposited SBT films by the sol-gel method, onto Pt/TiO2/SiO2/Si (100) substrates, using capacitors of 5 x 10–4 cm-2 .In this work, we analysed the viability of this material as a FeRAM memory in real operating conditions, as a result of the variation of the polarisation measurements with time (retention), performed at room temperature and 75ºC.Este trabajo ha sido realizado con el apoyo del proyecto de la CICYT MAT98-1068.Peer reviewe

Feasibility of (Pb, Ca)TiO3 thin films deposited on Pt/TiO2/SiO2/Si(100) for switching applications

[ES] Se han depositado láminas delgadas de (Pb,Ca)TiO3 sobre substratos de Pt/TiO2/SiO2/Si(100) por centrifugación, partiendo de soluciones sintetizadas por sol -gel. La concentración de las soluciones y el contenido de PbO se seleccionaron para minimizar las tensiones de las láminas cristalizadas y obtener la adecuada estequiometria. La cristalización mediante un calentamiento rápido (RTP), conduce a láminas con orientaciones preferentes [001]/[001], reducida capa interfacial ferroeléctrico-Pt y composición deseada. Los parámetros ferroeléctricos obtenidos muestran una mejora de las propiedades. Estas láminas presentan una fatiga y envejecimiento mucho más moderados que otros materiales alternativos depositados sobre substratos iguales, lo que permite considerar al método descrito como muy valioso para conseguir materiales susceptibles de emplear en aplicaciones de conmutación.[EN] (Pb,Ca)TiO3 ferroelectric thin films have been spin-coated on Pt/TiO2/SiO2/Si(100) substrates from sol-gel synthesized solutions. Selecting the solution concentrations and the excess of PbO content, stoichiometric composicion with reduced strains are obtained. Crystallization process by rapid thermal treatment (RTP) promote preferred orientations [001]/[100] resulting a thiner ferroelectric-platinum interface layer, which causes the improvement of fatigue and retain behaviour, despite the use of platinum electrodes. These experimental finds let to cosider the described methode of processing very convenient to prepare thin films of this composition to use on switching applications such as non volatil RAM memories.Peer reviewe

LAF1, a MYB transcription activator for phytochrome A signaling

The photoreceptor phytochrome (phy) A has a well-defined role in regulating gene expression in response to specific light signals. Here, we describe a new Arabidopsis mutant, laf1 (long after far-red light 1) that has an elongated hypocotyl specifically under far-red light. Gene expression studies showed that laf1 has reduced responsiveness to continuous far-red light but retains wild-type responses to other light wavelengths. As far-red light is only perceived by phyA, our results suggest that LAF1 is specifically involved in phyA signal transduction. Further analyses revealed that laf1 is affected in a subset of phyA-dependent responses and the phenotype is more severe at low far-red fluence rates. LAF1 encodes a nuclear protein with strong homology with the R2R3-MYB family of DNA-binding proteins. Experiments using yeast cells identified a transactivation domain in the C-terminal portion of the protein. LAF1 is constitutively targeted to the nucleus by signals in its N-terminal portion, and the full-length protein accumulates in distinct nuclear speckles. This accumulation in speckles is abolished by a point mutation in a lysine residue (K258R), which might serve as a modification site by a small ubiquitin-like protein (SUMO)

Superintegrability and higher order polynomial algebras II

In an earlier article, we presented a method to obtain integrals of motion and polynomial algebras for a class of two-dimensional superintegrable systems from creation and annihilation operators. We discuss the general case and present its polynomial algebra. We will show how this polynomial algebra can be directly realized as a deformed oscillator algebra. This particular algebraic structure allows to find the unitary representations and the corresponding energy spectrum. We apply this construction to a family of caged anisotropic oscillators. The method can be used to generate new superintegrable systems with higher order integrals. We obtain new superintegrable systems involving the fourth Painleve transcendent and present their integrals of motion and polynomial algebras.Comment: 11 page

Estimación de la resistencia a compresión simple del jabre estabilizado “in situ” con cemento como material en la formación de explanadas de carreteras

Granite rock has powerful alterations at several meters of depth. The clayed sand resulting is commonly known as jabre. This “in situ” mixture of cement-stabilized soil requires a laboratory formula. Even when the test section is correctly verified, the mechanical properties of the homogeneous mixture of jabre exhibit high degrees of dispersion. The laboratory work undertaken included particle-size analysis and screening, defini­tion of liquid and plastic limits, compressive strength, dry density and moisture content over stabilized samples, modified Proctor, California Bearing Ratio (CBR) and the determination of the workability of the hydrauli­cally bound mixtures. The stress resistance curve was analyzed by means of a multilinear model of unconfined compressive strength (UCS). Since practical engineering only requires UCS for 7 days, in order to gain greater knowledge of the material, other UCS transformations were used at other curing times such as 7, 14 and 28 days.La roca granítica presenta habitualmente un horizonte de alteración con varios metros de potencia. La arena arcillosa resultante como producto de alteración se deno­mina comúnmente jabre. Aunque la fórmula de trabajo de la estabilización de jabre con cemento se verifique correctamente en tramos de prueba, la estabilización “in situ” del jabre con cemento presenta habitualmente elevadas dispersiones. Entre los ensayos de laboratorio efectuados se encuentran los ensayos de análisis granulo­métrico, límites de Atterberg, resistencia a compresión simple (RCS), la densidad y humedad sobre probetas de suelo estabilizado, Proctor modificado, índice CBR (California Bearing Ratio) y el plazo de trabajabilidad de la mezcla con cemento. La curva de endurecimiento del suelo estabilizado fue ajustada mediante un modelo multi­lineal. Aunque tradicionalmente se especifique la RCS a 7 días, buscando definir un mejor comportamiento del material, los autores calcularon otros modelos de jabre estabilizado para roturas a 7, 14 y 28 días

The use of HSQoL-24 in an assessment of quality-of-life impairment among hidradenitis suppurativa patients: First look at real-life data

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disorder with well-documented effects on patients’ quality of life (QoL). The aim of this study was to evaluate the QoL of patients with HS via the use of a newly developed questionnaire: Hidradenitis Suppurativa Quality of Life-24 (HSQoL-24). This study was performed on a population of 342 HS patients. Their QoL was assessed via the HSQoL-24 questionnaire. The perceived impairment of QoL due to HS in the studied group was considered to be serious (mean HSQoL-24 score: 58.3 ± 21.0 points). Women tended to experience a significantly higher impact from the disease than men (61.6 ± 19.2 points vs. 51.1 ± 23.1 points, p < 0.001). The HS severity had an effect on the perceived QoL, with statistically significant differences being evident between the self-assessed HS severity groups. The level of QoL impairment correlated positively with the number of affected body areas (r = 0.285, p < 0.001) and the duration of the disease (r = 0.173, p = 0.001), while the patients’ age at disease onset correlated negatively with the HSQoL-24 global score (r = -0.182, p = 0.001). Patients living in their family house scored higher than other groups. The least affected were patients who lived alone. The study shows that the HSQoL-24 questionnaire is a reliable, HS-specific tool for measuring the QoL among patients with HS in real-life clinical settings. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Properties of morphotropic phase boundary Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 films with submicron range thickness on Si based substrates

Abstract The electrical properties of (1- Self polarisation is thus present, which indicates the existence of an internal electric field that is most probably a substrate effect. Films would be then in a phase instability, at an intermediate state between the relaxor and ferroelectric ones, and under a bias electric field, which would explain the very high spontaneous pyroelectric response found.

The Chicken Yolk Sac IgY Receptor, a Mammalian Mannose Receptor Family Member, Transcytoses IgY across Polarized Epithelial Cells

In mammals the transfer of passive immunity from mother to young is mediated by the MHC-related receptor FcRn, which transports maternal IgG across epithelial cell barriers. In birds, maternal IgY in egg yolk is transferred across the yolk sac to passively immunize chicks during gestation and early independent life. The chicken yolk sac IgY receptor (FcRY) is the ortholog of the mammalian phospholipase A2 receptor, a mannose receptor family member, rather than an FcRn or MHC homolog. FcRn and FcRY both exhibit ligand binding at the acidic pH of endosomes and ligand release at the slightly basic pH of blood. Here we show that FcRY expressed in polarized mammalian epithelial cells functioned in endocytosis, bidirectional transcytosis, and recycling of chicken FcY/IgY. Confocal immunofluorescence studies demonstrated that IgY binding and endocytosis occurred at acidic but not basic pH, mimicking pH-dependent uptake of IgG by FcRn. Colocalization studies showed FcRY-mediated internalization via clathrin-coated pits and transport involving early and recycling endosomes. Disruption of microtubules partially inhibited apical-to-basolateral and basolateral-to-apical transcytosis, but not recycling, suggesting the use of different trafficking machinery. Our results represent the first cell biological evidence of functional equivalence between FcRY and FcRn and provide an intriguing example of how evolution can give rise to systems in which similar biological requirements in different species are satisfied utilizing distinct protein folds