EXTENSION OF LIPSCHITZ-TYPE OPERATORS ON BANACH FUNCTION SPACES

[EN] We study extension theorems for Lipschitz-type operators acting on metric spaces and with values on spaces of integrable functions. Pointwise domination is not a natural feature of such spaces, and so almost everywhere inequalities and other measure-theoretic notions are introduced. We analyze Lipschitz-type inequalities in two fundamental cases. The first concerns almost everywhere pointwise inequalities, while the second considers dominations involving integrals. These Lipschitz-type inequalities provide a suitable frame to work with operators that take values on Banach function spaces. In the last part of the paper we use some interpolation procedures to extend our study to interpolated Banach function spaces.The second and the third authors gratefully acknowledge the support of the Ministerio de Ciencia, Innovacion y Universidades (Spain) and FEDER under grant MTM2016-77054-C2-1-P2Cavalcante, WV.; Rueda, P.; Sánchez Pérez, EA. (2021). EXTENSION OF LIPSCHITZ-TYPE OPERATORS ON BANACH FUNCTION SPACES. Topological Methods in Nonlinear Analysis. 57(1):343-364. https://doi.org/10.12775/TMNA.2020.026S34336457

Aplicación de modelos genéticamente manipulados "knoch-out" en neuro-oftalmología.

RESUMEN Objetivo: Estudiar las funciones que realizan las proteínas ApoE, PTEN y P27kip1, sobre el nervio óptico (NO) y retina. Material y Métodos: Este trabajo se ha llevado a cabo en ratones distribuidos en cinco grupos: 1) ratones wildtype (grupo Control), 2) ratones ApoE Knockout (grupo ApoE), 3) ratones ApoE Knockout suplementados con una dieta hipercolesterolémica (ApoE+D), 4) ratones heterocigotos PTEN Knockout, (grupo PTEN) y 5) ratones P27kip1 Knockout (grupo P27). Se realizaron análisis morfológicos y morfométricos en las retinas y nervios ópticos de todos los grupos, técnicas de inmunocitoquímica, western-blot e inmunobloting, para examinar la expresión de la proteína básica de la mielina (MBP) y proteína fibrilar ácida de la glía (GFAP). Sometimos a los cinco grupos de ratones a una modificación de la prueba de escape de Morris. Resultados: En los grupos ApoE y ApoE+D, tanto las áreas de la sección trasversal del NO como de los axones fueron significativamente mayores que las del grupo Control (P<0.001, P<0.001). A pesar del aumento en el tamaño, éste no se acompañó de incremento en el número total de axones. Hemos comprobado la presencia de alteraciones en las células macrogliales, en los axones y vainas de mielina, que se reflejaban en la disminución de la expresión de las proteínas MBP y GFAP. No se observaron diferencias entre los NO de los ratones ApoE Knockout y los ApoE+D Knockout. Se observó una disminución del grosor en las retinas de los grupos ApoE y ApoE+D (P<0.001, P<0.001), acompañado de una disminución en la densidad celular retiniana, a expensas, fundamentalmente, de las capas nucleares externa e interna, más notable en el grupo alimentado con dieta hipercolesteromiante. Hemos documentado el engrosamiento de la Membrana de Bruch con presencia de vacuolas, también mas evidente en el grupo alimentado con el suplemento dietético lipídico. Este grupo presentaba además disminución de la expresión de GFAP en retina, sin influencia de la dieta recibida. En el grupo P27, la superficie transversal de NO y axones eran significativamente mayores que las del grupo Control (P<0.001). Este aumento se acompañó de un incremento del número total de fibras ópticas. Se apreciaron alteraciones ultraestructurales en astrocitos, oligodendrocitos, axones y mielina, acompañadas de anomalías en la expresión de MBP y fundamentalmente de GFAP. En las retinas del grupo P27 existía una disminución muy significativa del grosor retiniano total. En el estudio ultraestuctural, tanto en los fotorreceptores como en el epitelio pigmentario, se detectaron múltiples alteraciones, acompañadas de una drástica disminución en la expresión retiniana de GFAP. En el grupo PTEN, las áreas transversales del NO y de los axones fueron significativamente mayores que las del grupo Control (P<0.001). Sin embargo, no existió aumento significativo en el número total de axones, ni se apreciaron alteraciones en la expresión de MBP y de GFAP. Se detectó un aumento significativo del grosor retiniano total en relación a los controles (P<0.001). Conclusiones: La falta de la expresión de ApoE induce en el NO de los ratones un patrón hipertrófico con marcadas alteraciones estructurales, independientemente de los niveles séricos lipídicos. En las retinas de estos animales predomina un patrón hipotrófico e hipoplásico. Las alteraciones morfológicas del NO y retina, producidas en estos ratones, no provocan alteraciones en la percepción de estímulos luminosos. La ausencia de expresión de P27kip1 produce sobre los NO hipertrofia e hiperplasia, mientras que en la retina aparecen signos de atrofia. En ambas estructuras se detectan alteraciones morfológicas muy importantes. Por último, la ausencia de expresión de PTEN induce, tanto en el NO como en la retina, un patrón hipertrófico. ____________________________________________________________________________________________________Our purpose was to study the functions of the ApoE, PTEN and P27kip1 proteins, in the optic nerve (ON) and retina. This study has been carried out with mice distributed in five groups: 1) wildtype mice (Control group), 2)ApoE Knockout mice (ApoE group), 3) ApoE Knockout mice fed with high cholesterol diet (ApoE+ D group), 4) PTEN heterocigotus Knockout mice, (PTEN group) and 5) P27kip1 Knockout mice (P27 group). In the ApoE and ApoE+ D groups, the cross-sectional areas of the ON and axons were significantly higher than in the Control group (P< 0.001, P< 0.001). Morphological alterations were detected in the macroglial cells, axons and myelin sheaths. No significant changes were noticed in the ON between the ApoE and the ApoE+ D mice. ApoE and ApoE+ D groups showed a significant reduction in the retinal thickness (P< 0.001, P< 0.001), which was more important in the group fed with hypercholeterolemic diet. In the P27 group, the ON cross-sectional area was significantly higher than in the Control group (P< 0.001). This increase was accompanied with an increment in the total number of optic fibres. Ultraestructural alterations were detected in astrocytes, oligodendrocytes, axons and myelin. The P27 group also showed a significant decrease in the retinal thickness with important morphological alterations. In PTEN group, the ON and the axonal transversal areas were significantly higher than in the Control group (P< 0.001). We can conclude that the no-expression of ApoE induces in the ON mice an hypertrophic pattern with important structural alterations, independently with the lipidic cholesterol levels. An hypotrophic pattern was present in the retinas of these animals. The absence in the expression of P27kip1 protein induces hypertrophia and hyperplasia in the ON, while signs of disorganization and atrophy are presents in the retina. Lastly, the no-expression of PTEN protein induces, in the ON and retina, a hypertrophic pattern

Analyzing the major drivers of NEE in a Mediterranean alpine shrubland

Two years of continuous measurements of net ecosystem exchange (NEE) using the eddy covariance technique were made over a Mediterranean alpine shrubland. This ecosystem was found to be a net source of CO2 (+ 52 ± 7 g C m−2 and + 48 ± 7 g C m−2 for 2007 and 2008) during the two-year study period. To understand the reasons underlying this net release of CO2 into the atmosphere, we analysed the drivers of seasonal variability in NEE over these two years. We observed that the soil water availability – driven by the precipitation pattern – and the photosynthetic photon flux density (PPFD) are the key factors for understanding both the carbon sequestration potential and the duration of the photosynthetic period during the growing season. Finally, the effects of the self-heating correction to CO2 and H2O fluxes measured with the open-path infrared gas analyser were evaluated. Applying the correction turned the annual CO2 budget in 2007 from a sink (− 135 ± 7 g C m−2) to a source (+ 52 ± 7 g C m−2). The magnitude of this change is larger than reported previously and is shown to be due to the low air density and cold temperatures at this high elevation study site.This research was supported by the regional government Junta de Andalucía, project BACAEMÁ (RNM-332) and the Spanish National flux tower network CARBORED-ES (CGL2006-14195-C02-01/CLI)

Enhanced catalytic activity and stability for the electrooxidation of formic acid on lead modified shape controlled platinum nanoparticles

High catalytic activity for formic acid oxidation reaction (FAOR) is demonstrated in Pb modified shape-controlled Pt nanoparticles (NPs). Cyclic voltammetry is used to follow the effective modification of Pt NPs by Pb. Octahedral shaped Pt NPs (having a (111) preferential surface structure) modified by Pb are proved the most active electrocatalyst studied towards FAOR and display a catalytic activity of c.a. 7 mA cm−2 at 0.5 V in 0.1 M formic acid solution. This current density represents an enhancement factor of 29.5 with respect to the unmodified Pt NPs and this is 2.7 and 2.3 times higher than that found on Tlθ/100-Pt NPs and Sbθ/111-Pt NPs, respectively, some of the most active electrocatalysts based on adatoms modified Pt NPs reported so far. This outstanding activity is displayed at maximum Pb coverage and also confers a wide electrocatalyst stability over the entire potential range studied. FAOR is also studied using scanning electrochemical microscopy (SECM) by the micropipette delivery/substrate collection (MD/SC) working mode as a preliminary rapid test to identify active electrocatalysts. In particular, the remarkable activity enhancement exhibited by a Pt ultramicroelectrode (100 μm diameter) modified by Pb is rapidly imaged by SECM providing preliminary catalyst performance information. Thus, this technique emerges as a suitable and fast method to test, and in some cases quantify, catalyst activity for reactions of interest in fuel cell applications.This work has been financially supported by the MICINN (Spain)(projects CTQ2013-44083-P and CTQ2013-48280-C3-3-R), Generalitat Valenciana (project PROMETEOII/2014/013, FEDER) and CNRS (project Défi Instrumentation aux limites 2015)

Study of erosion behaviour of conventional and nanostructured WC-12Co coatings sprayed by atmospheric plasma

Thermal sprayed WC-Co coatings are used extensively to enhance the wear resistance of a wide range of engineering components. In this paper, erosive resistance of plasma atmospheric sprayed WC-12Co coatings has been evaluated. Solid particle erosion tests were conducted on these coatings at different angles of impact with silica and alumina abrasives of size 250 µm. Coatings have been deposited by using micrometric and nanometric agglomerated powders, employing H2 and He as plasmogen gas. In order to determine the erosion regime (ductile or brittle), the influence of impact angle on the erosion rate has been studied. Optical microscope and FESEM have been used to analyze the eroded surface. The influence of the plasmogen gas and the powder employed on the erosive behaviour of the coating has been evaluated. An attempt to connect the erosive behaviour with mechanical properties and microstructure has been made. Hardness has been determined by means of several measurements of Vickers microhardness; fracture toughness has been estimated through indentation method. Identification of phases has been made by means of X Ray diffractio

Oxygen crossover effect on palladium and platinum based electrocatalysts during formic acid oxidation studied by scanning electrochemical microscopy

The electrocatalytic activity towards formic acid oxidation reaction (FAOR) in the presence of simultaneous oxygen reduction reaction (ORR) displayed by 5 different metallic nanoparticles (NPs) (Pt100, Pt75Pd25, Pt50Pd50, Pt25Pd75 and Pd100) was studied and compared using chronoamperometry and the micropipette delivery/substrate collection (MD/SC) mode of the scanning electrochemical microscopy (SECM). This is of special interest for understanding the O2 crossover effect in direct formic acid fuel cells (DFAFCs) and to search highly selective electrocatalysts useful in mixed-reactant fuel cells (MRFCs). A detailed analysis of the SECM results in comparison with chronoamperometry demonstrates, for the first time, the relevant role played by dissolved O2 in solution on the Pd100 NPs deactivation during FAOR, which cannot be explained neither by the specific adsorption of dichloroethane (DCE) on Pd nor by a simple addition of two opposed currents coming from simultaneous FAOR and ORR. Two main mechanistic factors are proposed for explaining the different sensitivity towards O2 presence in solution during FAOR when comparing Pd- and Pt-rich catalysts. On the one hand, the relevance of H2O2 production (ORR byproduct) and accumulation on Pd NPs, which alters its performance towards FAOR. On the other hand, the predominance of the poisoning pathway forming COads during FAOR on Pt NPs, whose oxidation is facilitated in the presence of traces of O2. Interestingly, the deactivation effect displayed on Pd100 NPs during FAOR due to the H2O2 generation and accumulation becomes negligible if a convective regime is applied in solution. SECM is proved as a fast and powerful technique for studying O2 crossover effect in different electrocatalysts and for identifying highly selective electrocatalysts candidates for MRFCs. In particular, among the samples evaluated, Pt75Pd25 NPs present the highest average performance for FAOR in 0.5 M H2SO4 solution in the presence of O2 within the potential range under study (0.3–0.7 V vs RHE).This work was financially supported by CNRS (projet ImaECell, Défi Instrumentation aux limites 2015), MINECO (projects CTQ2013-44083-P and CTQ2013-48280-C3-3-R) and Generalitat Valenciana (project PROMETEOII/2014/013). J. Solla-Gullón acknowledges financial support from VITC (Vicerrectorado de Investigación y Transferencia de Conocimiento) of the University of Alicante

Thermal characterization of Montmorillonite clays saturated with various cations

Emanation thermal analysis (ETA), thermogravimetry and high temperature XRD were used to characterize the thermal behavior during dehydration of natural Na montmorillonite (Upton Wyoming, USA) and homoionic montmorillonite (MMT) samples saturated with different cations, i.e. Li+, Cs+, NH 4 +, Mg2+ and Al3+. ETA results characterized radon mobility and microstructure changes that accompanied the mass loss of the samples due to dehydration on heating in air. A collapse of interlayer space between the silicate sheets after water release from the MMT samples was characterized by a decrease of the radon release rate, ΔE. Decreases in c-axis basal spacing (d 001) values determined from XRD patterns for the different montmorillonite samples follow the sequence: Mg−MMT>Al−MMT>Li−MMT>Na−MMT>NH4−MMT>Cs−MMT The decrease of the radon release rate (ΔE) determined by ETA that characterized microstructure changes due to collapse of interlayer space corresponded well to differences in the c-axis basal spacing (Δd 001) values determined from the XRD patterns before and after samples dehydration.Ministry of Education of Czech Republic LA–292España Ministerio de educación MAT2004-0264

Cervantesiaceae: nuevo registro de una familia naturalizada para la flora de México.

Se registra por primera vez para México la especie naturalizada Acanthosyris glabrata (familia Cervantesiaceae), un árbol hemiparásito sólo conocido del noroeste de Sudamérica. Se proporciona información sobre su hábitat y se presenta una ilustración de la especie. Se propone una hipótesis de comercio maritimo entre Ecuador y México para explicar la presencia del taxón en el occidente de México, en un área que dista 3500 km de su distribución original.We register for the first time in Mexico the naturalized species Acanthosyrisglabrata (family Cervantesiaceae), a hemiparasitic tree only known from northwestern South America. We provide information about its habitat and present an illustration of the species. We propose a hypothesis of maritime commerce between Ecuador and Mexico to account for the presence of the taxon in western Mexico, in an area 3500 km away from its original known distribution

Artrodesis subtalar primaria como tratamiento de fracturas conminutas de calcáneo Sanders tipo IV

Las fracturas conminutas Sanders IV de calcáneo dan lugar, en la mayoría de los casos, a una artrosis subtalar postraumática dolorosa e incapacitante, que en muchas ocasiones, requiere una artrodesis subtalar secundaria. Esta artrodesis puede ser técnicamente compleja, ya que no se trata de una fijación in situ, sino que requiere la realización de osteotomías de corrección a nivel del cuerpo del calcáneo en la misma cirugía.Material y métodos. Presentamos 4 pacientes con fracturas conminutas de calcáneo Sanders tipo IV que fueron tratadas mediante una artrodesis subtalar primaria con reconstrucción concomitante del cuerpo del calcáneo. El seguimiento medio fue de 15 meses. Resultados. Obtuvimos la consolidación ósea, tanto de la artrodesis como de la fractura, alrededor de los 4 meses, sin existir signos de artrosis en otras articulaciones. No hubo ninguna complicación de herida quirúrgica, ni aparecieron otras complicaciones típicas de estas lesiones, como impingement de peroneos, problemas con el calzado o bloqueo o degeneración de la articulación tibio talar durante el seguimiento. La puntuación AOFAS media a los 12 meses fue de 78. Conclusiones. La artrodesis subtalar primaria con la corrección inicial de las deformidades asociadas en el cuerpo del calcáneo (acortamiento, ensanchamiento y varo) evita complicaciones posteriores y obtiene buenos resultados