Chemical conversion treatments to protect biodegradable magnesium in applications as temporary implants for bone repair

7 páginas, 7 figuras, 1 tabla.[ES] El presente estudio se desarrolló para mejorar la resistencia a la corrosión del magnesio puro, modificando su superficie mediante recubrimientos de conversión química. Se generaron capas de carbonato y fluoruro por inmersión en soluciones de NaHCO3 al 9 % y de HF al 48 %, respectivamente. La resistencia a la corrosión de las muestras con recubrimiento se evaluó en comparación con la del sustrato desnudo mediante técnicas electroquímicas en una solución fisiológica (PBS). Los resultados obtenidos han mostrado que el recubrimiento de carbonato no es capaz de proteger de la degradación al sustrato de magnesio. Por el contrario, el recubrimiento de fluoruro ha demostrado aumentar, significativamente, la resistencia a la corrosión del magnesio en medio fisiológico. La alta compacidad y adherencia al sustrato metálico de la capa de MgF2 generada mediante este sencillo tratamiento de conversión química confieren al recubrimiento buenas propiedades protectoras.[EN] The present study was developed to improve the corrosion resistance of pure magnesium by applying chemical conversion coatings. Carbonate and fluoride layers were generated by immersion in solutions of NaHCO3 of concentration 9 wt.%and HF of concentration 48 wt.%, respectively. Corrosion resistance of the coated samples was evaluated in comparison with that of the uncoated substrate by electrochemical techniques in a physiological solution (PBS). Results have shown that the carbonate coating is not viable to be used for protecting magnesium against corrosion.On the contrary, the fluoridemagnesiumcoating significantly increases the corrosion resistance ofmagnesium in physiological medium. The high compactness and adherence to the base metal of theMgF2 layer produced by this simple chemical conversion treatment confer the protective properties to the coating.Los autores agradecen al MEC la financiación del proyecto con referencia MAT 2008-06719-C03-01. M. Carboneras agradece al CSIC la concesión de un contrato JAE-Doc.Peer reviewe

Bioactive pectic polysaccharides from bay tree pruning waste: Sequential subcritical water extraction and application in active food packaging

The potential isolation of bio-active polysaccharides from bay tree pruning waste was studied using sequential subcritical water extraction using different time-temperature combinations. The extracted polysaccharides were highly enriched in pectins while preserving their high molecular mass (10–100 kDa), presenting ideal properties for its application as additive in food packaging. Pectin-enriched chitosan films were prepared, improving the optical properties (=95% UV-light barrier capacity), antioxidant capacity (?95% radical scavenging activity) and water vapor permeability (=14 g·Pa-1·s-1·m-1·10-7) in comparison with neat chitosan-based films. Furthermore, the antimicrobial activity of chitosan was maintained in the hybrid films. Addition of 10% of pectins improved mechanical properties, increasing the Young's modulus 12%, and the stress resistance in 51%. The application of pectin-rich fractions from bay tree pruning waste as an additive in active food packaging applications, with triple action as antioxidant, barrier, and antimicrobial has been demonstrated.Authors would like to thank the Spanish Ministry of Science and Innovation (Ramon y Cajal contract RYC-2015-17109) and Universidad de Cordoba, ´ Spain (Predoctoral Grant 2019) for the financial support during this work

FOOTHILL COLOMBIAN PLAIN, HYDRODYNAMIC AND HYDROGEOCHEMICAL PATHWAY HYPOTHESIS, HYDROGEOLOGIC METHODS.

  La nueva información de presión de formación, fisicoquímica e isotopía ambiental, permitieron la elaboración de hipótesis preeliminares sobre el origen y movimiento del agua de formación asociada a hidrocarburos en Piedemonte y parte central de los Llanos Orientales. En Piedemonte, se sugiere la presencia de sistemas hidráulicos individuales sobrepresionados, asociados a cada estilo estructural; encontrándose un sistema levemente subpresionado al sur de Cupiagua. El origen de las aguas de formación es confuso, encontrándose aguas connatas con bajas salinidades, aguas empobrecidas isotópicamente con altas salinidades y aguas con desviaciones en las trayectorias isotópicas, sugiriendo la acción de procesos de mezcla y/o interacción roca-fluido. Se determinó flujo SW, con una anomalía de flujo W-SW (Cusiana), favorecida por canales permeables originados por la yuxtaposición de litologías permeables.   En Llanos, se sugieren sistemas hidráulicos levemente sobrepresionados (menos que en Piedemonte), con zonas de subpresión para campos paralelos y adyacentes al frente de deformación. La isotopía sugiere la acción de procesos de mezcla y/o interacción roca fluido. Anomalías de presión y fisicoquímica, sugieren mezcla de fluidos en forma ascendente, con plumas dispuestas paralelamente y adyacentemente al frente de deformación. El flujo es N-NW desde el SE, hacia zonas subpresionadas al centro de la cuenca.   Palabras Claves: Hidrodinámica, Hidrogeoquímica, Migración, Piedemonte, Llanos Orientales      New information of formation pressure, groundwater physicochemical and environmental isotopes, allowed to carry out hypothesis on the origin and movement of formation water associated to hydrocarbons in Foothill and central part of the Llanos Orientales basin. In Piedemonte, overpressured individual hydraulic systems are suggested, associated to each structural style; founding a slightly subpressured system to the south of Cupiagua. The formation water origin in not clear, founding cognate waters with low salinities, waters with isotopic impoverishment and high salinities, and waters with deviations in the isotopic trajectories, that suggest action of mixture processes and/or interaction rock-fluid. It has been established a SW flow, with a W-SW anomaly (Cusiana), which is favoured by permeable channels originated by juxtaposition of permeable lythologies.   In Llanos, slightly overpressured hydraulic systems are suggested (less than in Piedemonte), with subpressured zones for field parallel and adjacent to the deformation front. Isotopic analysis suggests the action of mixture processes and/or interaction fluid-rock. Pressure and physicochemical anomalies, suggest mixture of fluid in ascending form, with plumes parallel and adjacent to the deformation front. The flow is N-NW from SE, towards subpressured zones in the basin.   Key words: Hydrodynamic, Hidrogeochemical, Migration, Piedemonte, Llanos Orientale

FOOTHILL COLOMBIAN PLAIN, HYDRODYNAMIC AND HYDROGEOCHEMICAL PATHWAY HYPOTHESIS, HYDROGEOLOGIC METHODS.

  La nueva información de presión de formación, fisicoquímica e isotopía ambiental, permitieron la elaboración de hipótesis preeliminares sobre el origen y movimiento del agua de formación asociada a hidrocarburos en Piedemonte y parte central de los Llanos Orientales. En Piedemonte, se sugiere la presencia de sistemas hidráulicos individuales sobrepresionados, asociados a cada estilo estructural; encontrándose un sistema levemente subpresionado al sur de Cupiagua. El origen de las aguas de formación es confuso, encontrándose aguas connatas con bajas salinidades, aguas empobrecidas isotópicamente con altas salinidades y aguas con desviaciones en las trayectorias isotópicas, sugiriendo la acción de procesos de mezcla y/o interacción roca-fluido. Se determinó flujo SW, con una anomalía de flujo W-SW (Cusiana), favorecida por canales permeables originados por la yuxtaposición de litologías permeables.   En Llanos, se sugieren sistemas hidráulicos levemente sobrepresionados (menos que en Piedemonte), con zonas de subpresión para campos paralelos y adyacentes al frente de deformación. La isotopía sugiere la acción de procesos de mezcla y/o interacción roca fluido. Anomalías de presión y fisicoquímica, sugieren mezcla de fluidos en forma ascendente, con plumas dispuestas paralelamente y adyacentemente al frente de deformación. El flujo es N-NW desde el SE, hacia zonas subpresionadas al centro de la cuenca.   Palabras Claves: Hidrodinámica, Hidrogeoquímica, Migración, Piedemonte, Llanos Orientales      New information of formation pressure, groundwater physicochemical and environmental isotopes, allowed to carry out hypothesis on the origin and movement of formation water associated to hydrocarbons in Foothill and central part of the Llanos Orientales basin. In Piedemonte, overpressured individual hydraulic systems are suggested, associated to each structural style; founding a slightly subpressured system to the south of Cupiagua. The formation water origin in not clear, founding cognate waters with low salinities, waters with isotopic impoverishment and high salinities, and waters with deviations in the isotopic trajectories, that suggest action of mixture processes and/or interaction rock-fluid. It has been established a SW flow, with a W-SW anomaly (Cusiana), which is favoured by permeable channels originated by juxtaposition of permeable lythologies.   In Llanos, slightly overpressured hydraulic systems are suggested (less than in Piedemonte), with subpressured zones for field parallel and adjacent to the deformation front. Isotopic analysis suggests the action of mixture processes and/or interaction fluid-rock. Pressure and physicochemical anomalies, suggest mixture of fluid in ascending form, with plumes parallel and adjacent to the deformation front. The flow is N-NW from SE, towards subpressured zones in the basin.   Key words: Hydrodynamic, Hidrogeochemical, Migration, Piedemonte, Llanos Orientale

SIMULACION EN FDFD PARA DESCRIBIR EL FENOMENO DE IRIDISCENCIA EN LOS ELITROS DEL Euchroma gigantean

Se presenta una discusión acerca del fenómeno de iridiscencia presente en los élitros del Euchroma gigantea, insecto que pertenece a la familia Buprestidae, los denominados escarabajos joya. Las ondas reflejadas sugieren que el fenómeno de iridiscencia es estructural, justo como se manifiesta en las mariposas Morpho o en los escarabajos Hoplia coerulea. Las imágenes obtenidas por SEM muestran una la estructura superficial de los élitros como un arreglo aleatorio de defectos en un sustrato dieléctrico orgánico.Como el componente principal del exoesqueleto de los artrópodos es la quitina, se hace la suposición que el sustrato es completamente quitina y también se asume que los defectos son columnas de aire. Es así como el sistema es modelado como un cristal fotónico dos-dimensional. Debido a que las energías características obtenidas para los modos activos de la estructura no pertenecen al rango visible, se concluye que el fenómeno de iridiscencia no es causado por la estructura superficial del élitro.In this work we present a discussion about the iridescence phenomena exhibited on Euchroma gigantea’s elytra (1), a beetle which belongs to the family of Buprestidae, the jewel beetles. The reflectance suggest that iridescence phenomena is structural, the same as Morpho butterflies or the Hoplia coerulea beetles. The SEM images reveals a superficial structure of the elytra, as an aleatory arrange of defects in a dielectric organic substrate. As the main component on exoskeletons of arthropods is the chitin, we suppose the elytra are completely made of chitin and also is assumed the defects are air columns. That is how the system is modeled as a two dimensional photonic crystal.Because of the characteristics energies of each active mode calculated for the estructure doesn’t belong to visible range, is concluded that the iridiscence phenomena is not caused by its superficial structure

Accelerated and Scalable C(sp³)-H Amination via Decatungstate Photocatalysis Using a Flow Photoreactor Equipped with High-Intensity LEDs

[Image: see text] Carbon–nitrogen bonds are ubiquitous in biologically active compounds, prompting synthetic chemists to design various methodologies for their preparation. Arguably, the ideal synthetic approach is to be able to directly convert omnipresent C–H bonds in organic molecules, enabling even late-stage functionalization of complex organic scaffolds. While this approach has been thoroughly investigated for C(sp(2))–H bonds, only few examples have been reported for the direct amination of aliphatic C(sp(3))–H bonds. Herein, we report the use of a newly developed flow photoreactor equipped with high intensity chip-on-board LED technology (144 W optical power) to trigger the regioselective and scalable C(sp(3))–H amination via decatungstate photocatalysis. This high-intensity reactor platform enables simultaneously fast results gathering and scalability in a single device, thus bridging the gap between academic discovery (mmol scale) and industrial production (>2 kg/day productivity). The photocatalytic transformation is amenable to the conversion of both activated and nonactivated hydrocarbons, leading to protected hydrazine products by reaction with azodicarboxylates. We further validated the robustness of our manifold by designing telescoped flow approaches for the synthesis of pyrazoles, phthalazinones and free amines

Pollen record during the Eemian from the Fuentillejo maar-lake sequence (Ciudad Real, Spain)

The Fuentillejo maar is located in the Central Spanish Volcanic Field of Campo de Calatrava (Ciudad Real). Fuentillejo maar-Iake is a c10sed system covering over 142 m depth oflacustrine sediments; it is one ofthe best examples oflong and continuous cores at terrestrial site from the Iberian Peninsula. PalynoIogical, mineralogical and sedimentary facies analysis were performed to characterize the sedimentary record during the Last Interglacial. In core FUENT-l this period (dated in 133 ka-120 ka) is detected between 45,90-56,90 m depth. Sedimentology point of view is characterized by develop of lacustrine facies, fineIy laminated black-brown doIomicrite mud and sapropeIIayers (Sedimentary Units 16,6-17-18). The vegetation is characterised by high polIen taxa diversity (around 50 polIen taxa of terrestriaI types, 5 polIen taxa of aquatic types, spores and 9 types of non palynological microfossils-NPM) together with a high content in the Mediterranean and mesic forest components (Quercus evergreen, Oleaceae, Quercus decidous and CoryIus), tipical ofwarm and humid conditions, and a few content on Artemisia, Pinus and Juniperus taxa (typicaI of coId or warm arid phases). The scarce forest development can be interpreted from the polIen record of mesophilus and thermophilous vegetation of the FUENT-1 sequence, in which only 40-50% of total polIen come from arboreaI associations. These vaIues for arboreal pollen content are low compared with other European polIen sequences

Demografía y crecimiento primario durante la regeneración de tres especies de pino a lo largo de gradientes climáticos

13 páginas, 4 figuras y 3 tablasLa regeneración es un proceso crítico en la dinámica de los bosques, que presenta una marcada heterogeneidad temporal y espacial. En este trabajo se pretende avanzar en el conocimiento de las variables bióticas y abióticas que determinan a escala local la presencia, abundancia y crecimiento primario de plántulas de tres especies de pino: Pinus sylvestris, P. nigra y P. uncinata, y determinar el efecto relativo del clima. Para ello se muestrearon 216 parcelas distribuidas a lo largo de gradientes climáticos en siete localidades montañosas. Se censaron las plántulas recién emergidas y el resto de juveniles, y se midieron los crecimientos anuales. Los resultados mostraron diferencias significativas entre especies con efectos directos e indirectos del clima sobre la demografía y el estado de los juveniles. En las tres especies se apreció que la supervivencia de los juveniles aparecía desplazada hacia altitudes mayores respecto donde se producía el óptimo de la emergencia. Las relaciones locales de competencia y facilitación ejercieron efectos importantes sobre la regeneración de las tres especies, siendo éstos modulados por el clima.Ministerio Español de Innovación y Ciencia Consolider-Montes (CSD2008_00040), Los autores agradecen a toda la gente que hizo posible el trabajo de campo: R. Freire, B. Santamaría, J. Martínez, D. López, R. Ruíz-Puche, E. Molina, L. Ivorra, S. Martín, B. Ros y C. Boubekeur. También el apoyo estadístico de R. Manson.Proyecto europeo BACCARA (CE: FP7-226299, 7FP)Peer reviewe

Relative handgrip strength diminishes the negative effects of excess adiposity on dependence in older adults : a moderation analysis

Q1Adultos mayoresThe adverse effects of fat mass on functional dependence might be attenuated or worsened, depending on the level of muscular strength. The aim of this study was to determine (i) the detrimental effect of excess adiposity on dependence in activities of daily living (ADL), and (ii) whether relative handgrip strength (HGS) moderates the adverse effect of excess adiposity on dependence, and to provide the threshold of relative HGS from which the adverse effect could be improved or worsened. A total of 4169 participants (69.3 ± 7.0 years old) from 244 municipalities were selected following a multistage area probability sampling design. Measurements included anthropometric/adiposity markers (weight, height, body mass index, waist circumference, and waist-to-height ratio (WHtR)), HGS, sarcopenia “proxy” (calf circumference), and ADL (Barthel Index scale). Moderation analyses were performed to identify associations between the independent variable (WHtR) and outcomes (dependence), as well as to determine whether relative HGS moderates the relationship between excess adiposity and dependence. The present study demonstrated that (i) the adverse effect of having a higher WHtR level on dependence in ADL was moderated by relative HGS, and (ii) two moderation thresholds of relative HGS were estimated: 0.35, below which the adverse effect of WHtR levels on dependency is aggravated, and 0.62, above which the adverse effect of fat on dependency could be improved. Because muscular strength represents a critically important and modifiable predictor of ADL, and the increase in adiposity is inherent in aging, our results underscore the importance of an optimal level of relative HGS in the older adult population.Revista Internacional - Indexad