236 research outputs found

    Razón de sexos y morfometría de Calidris minutilla (Aves, Scolopacidae) en Cuba: un análisis a partir de especímenes en colecciones científicas

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    Las poblaciones de Calidris minutilla (zarapiquito) presentan variaciones morfométricas tanto en los lugares de cría como en los de invernada. Se documentan la razón de sexos (N = 99) y medidas morfométricas (N = 49) del zarapiquito en Cuba a partir de especímenes conservados en colecciones científicas. Además, se evalúan posibles variaciones en la longitud del pico teniendo en cuenta la ubicación longitudinal (grados) y el tipo de zona costera donde fue realizado el muestreo. La proporción de hembras fue del 0,47 y las medidas morfométricas estaban dentro del rango descrito para esta especie. Las variaciones en la longitud del pico fueron atribuibles únicamente al sexo y no a las características del lugar de captura.Calidris minutilla (Least Sandpiper) populations exhibit morphometric variation across breeding and wintering sites. We documented sex ratio (N = 99) and morphological measurements (N = 49) of Least Sandpiper inhabiting Cuba using specimens in museum collections. We also assessed bill length variation in relation to the longitude (degrees) and type of coastal zone where sampling was conducted. Proportion of female was 0.47 and morphometric measurements were within the range described for the species. Differences in bill length were explained by sex but not by sampling site characteristics.Las poblaciones de Calidris minutilla (zarapiquito) presentan variaciones morfométricas tanto en los lugares de cría como en los de invernada. Se documentan la razón de sexos (N = 99) y medidas morfométricas (N = 49) del zarapiquito en Cuba a partir de especímenes conservados en colecciones científicas. Además, se evalúan posibles variaciones en la longitud del pico teniendo en cuenta la ubicación longitudinal (grados) y el tipo de zona costera donde fue realizado el muestreo. La proporción de hembras fue del 0,47 y las medidas morfométricas estaban dentro del rango descrito para esta especie. Las variaciones en la longitud del pico fueron atribuibles únicamente al sexo y no a las características del lugar de captura

    Crystallization kinetics as a sensitive tool to detect degradation in poly(lactide)/poly(ε-caprolactone)/ PCL-co-PC copolymers blends

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    Poly(lactide)/poly(ε-caprolactone) blends (PLA/PCL) with composition 80/20 (w/w%) are immiscible but biodegradable and therefore often studied in the literature. We have prepared 80/20 PLA/PCL blends with and without poly(ε-caprolactone)-co-poly(carbonate) copolymers (block and random). The blends were prepared both by melt extrusion and by solution blending. The concentration of PCL-co-PC copolymers added to the blends was 2 wt%. Compression molded sheets and solvent cast films were evaluated by GPC (Gel Permeation Chromatography), TGA (Thermogravimetric Analysis), SEM (Scanning Electron Microscopy), PLOM (Polarized Light Optical Microscopy) and DSC (Differential Scanning Calorimetry). Copolymer addition causes a reduction of molecular weight in melt mixed blends. In particular, the random copolymer (PCL-ran-PC) causes the highest molecular weight reduction, since it has lower thermal stability, as shown by TGA. PLOM experiments show that these degraded PLA chains in melt-mixed blends can nucleate and grow faster than similar but undegraded PLA chains in solution-mixed blends. As a result, the PLA phase within melt mixed blends containing PCL-co-PC copolymers shows a higher tendency to crystallize during both isothermal and non-isothermal DSC experiments. Upon molecular weight reduction in melt mixed blends containing copolymers, PLA chains have a higher mobility resulting in faster diffusion towards the growing crystal front. Our results show crystallization kinetic measurements, performed by PLOM or DSC, are useful tools to qualitatively detect molecular weight changes produced by degradation of PLA chains, when the molecular weight reduction is not large enough to decrease Tm values

    Polyurethane/acrylic hybrid dispersions containing phosphorus reactive flame retardants as transparent coatings for wood

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    Phosphorus modified polyurethane/acrylic hybrid dispersions were prepared for flame retardant transparent wood coatings. The polymerisation was carried out in three steps. In the first one, the polyurethane was synthesised using an acrylic monomer as solvent. The second step involved water addition that promoted the phase inversion and lastly, acrylic part was polymerised. The phosphorous compounds were covalently linked to polyurethane using a phosphorylated polyol and to the acrylic phase using an acrylic phosphate. Polymerisation was monitored by FTIR and NMR and the molar mass of the hybrids was measured by AF4 and SEC. The effects of the phosphorus in fire-retardant properties were analysed by thermogravimetry and pyrolysis combustion flow calorimetry. The introduction of phosphorus did not produce significant changes in the polymerisation process but promoted the cross-linking of the coatings. The coated wood samples maintained the transparency and good properties with the introduction of phosphorus and presented a slight reduction in the Peak Heat Release Rate measured by cone calorimeter. The action of phosphorus as a fire retardant was effective as it gave rise to significant reduction of the CO and CO2 peaks.The funding received from University of the Basque Country (GIU19/077, predoctoral grant of M. Puyadena and postdoctoral grant of M. Cobos) and the Basque Government (IT1313-19, PIBA20/16) is grate-fully acknowledged. Technical and human support provided by SGIker is also sincerely acknowledged (UPV/EHU/ ERDF, EU

    Design and integration of WAAM technology and in situ monitoring system in a gantry machine

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    Wire arc additive manufacturing, WAAM, is a popular wire-feed additive manufacturing technology that creates components through the deposition of material layer-by-layer. WAAM has become a promising alternative to conventional machining due to its high deposition rate, environmental friendliness and cost-competitiveness. In this research work, an adaptation of a gantry machine with in-situ monitoring and a control system has been carried out, in order to expose the ability of the WAAM technology to fabricate complex-shaped parts. The retrofitting of the machine has been done in several layers called respectively hardware, control and software layers. For the validation of the implemented system, a stainless steel 316L demonstrator has been manufactured, and the required stages have been employed, including part design (CAD), process parameters selection, tool-path definition (CAM) and part manufacturing. This study has shown the feasibility of the adapted machine for additive manufacturing as a controlled process.The authors acknowledge the European Commission for support from project AMAZE (FP7-2012-NMP-ICT-FoF, project 313781) and the Basque Government for support from project EUSK-ADDI (Etorgai 2014)

    Unboxing the Chinese Blind Boxes among China's grown-up missing children: Probabilistic and elastic prosumption through mediated collection, exchange and resale of figurines

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    This paper situates the ‘Blind Box’ consumption, collection and prosumption practices in China within globalisation and the ‘media-mix’ fandom, which is to consume and resell media merchandise in opaque packages as probability goods. We re-centre the focus of fandom studies on the then much neglected ‘missing child’ and now the ‘emerging adult’ in a globalising world. We argue the Chinese emerging adult consumes, collects and resells Blind Boxes as a generative and agentic collection and fandom practice, defined as ‘probabilistic and elastic prosumption’ in a quasi-social and quasi-individual manner. We then critically examine and unpack the cultural production and meaning making process undertook by collectors who also accumulate sociality and form identity through affective and economic investments, mediated collection and exchange of figurines in a post-socialist and consumerist society

    In vitro antiatherogenicity of extracts from Halimeda incrassata seaweed: antioxidant activity and smooth muscle cell migration studies

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    Aim: The aim of this work was to evaluate the in vitro atheroprotective potential of the seaweed Halimeda incrassata in smooth muscle cell migration and lipoprotein oxidation in relation to its antioxidant activity. Material and methods: Antioxidant activity was determinate by DPPH• radical scavenging assay and ORAC method. The inhibitory effect of the aqueous extract on LDL oxidation mediated by Cu2+ ions was determinate by TBARS and conjugated diene quantification. The effect of the seaweed aqueous extract on smooth muscle cell migration was evaluated in MOVAS-1 mouse aortic smooth muscle cell. Results: The inhibitory effect of the aqueous extract on lipoprotein oxidation mediated by Cu2+ was demonstrated. Seaweed extract caused dose-dependent inhibition of TBARS (IC50 = 0.8 mg/mL) and conjugated dienes formation. The seaweed had a high antioxidant activity in the assays performed. The activity could be related to the phenolic content of Halimeda incrassata. Conclusions: In summary, the results of this study represent a further step in the characterization of the atheroprotective action of Halimeda incrassata and indicate the seaweed could be used for a nutraceutical and/or phytoterapeutic application.Objetivos: El objetivo de este trabajo fue evaluar el potencial ateroprotector in vitro del alga Halimeda incrassata en la migración de células de músculo liso de ratón y la oxidación de lipoproteínas en relación con su actividad antioxidante. Material y métodos: La actividad antioxidante fue determinada mediante los métodos de inhibición de radicales DPPH y la Capacidad antioxidante total (ORAC). La actividad inhibitoria de la oxidación de LDL mediada por iones Cu2+ se determinó por la cuantificación de TBARS y dienos conjugados. El efecto del extracto acuoso sobre la migración de las células de músculo liso se evaluó en la línea de células de músculo liso aórtica de ratón MOVAS-1. Resultados: Se demostró el efecto inhibidor del extracto sobre la oxidación de LDL mediada por Cu2+. El extracto del alga causa inhibición dosis-dependiente de la formación de TBARS (IC50 = 0,8 mg/mL) y dienos conjugados. Las algas tuvieron una alta actividad antioxidante en los ensayos realizados y podría estar relacionada con el contenido de compuestos fenólicos. Conclusiones: Los resultados de este trabajo representan un paso más en la caracterización de la acción ateroprotectora de Halimeda incrassata y evidencian sus posibles aplicaciones como nutracéutico y/o fitofármaco.The research was funded by IFS grant F/4897-1. Partial funding was also provided by CIHR grant MOP24447, the Canadian Research Chair award (D.B.) and a personal grant from GSEP, offered by the Canadian Bureau for International Education (A.C) and CNPq- (Brasil)

    Polyurethane/acrylic hybrid dispersions containing phosphorus reactive flame retardants as transparent coatings for wood

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    Phosphorus modified polyurethane/acrylic hybrid dispersions were prepared for flame retardant transparent wood coatings. The polymerisation was carried out in three steps. In the first one, the polyurethane was synthesised using an acrylic monomer as solvent. The second step involved water addition that promoted the phase inversion and lastly, acrylic part was polymerised. The phosphorous compounds were covalently linked to polyurethane using a phosphorylated polyol and to the acrylic phase using an acrylic phosphate. Polymerisation was monitored by FTIR and NMR and the molar mass of the hybrids was measured by AF4 and SEC. The effects of the phosphorus in fire-retardant properties were analysed by thermogravimetry and pyrolysis combustion flow calorimetry. The introduction of phosphorus did not produce significant changes in the polymerisation process but promoted the cross-linking of the coatings. The coated wood samples maintained the transparency and good properties with the introduction of phosphorus and presented a slight reduction in the Peak Heat Release Rate measured by cone calorimeter. The action of phosphorus as a fire retardant was effective as it gave rise to significant reduction of the CO and CO2 peaks.The funding received from University of the Basque Country (GIU19/077, predoctoral grant of M. Puyadena and postdoctoral grant of M. Cobos) and the Basque Government (IT1313-19, PIBA20/16) is gratefully acknowledged. Technical and human support provided by SGIker is also sincerely acknowledged (UPV/EHU/ERDF, EU)

    Supernucleation Dominates Lignin/Poly(ethylene oxide) Crystallization Kinetics

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    The effect of lignin nanoparticles (LNPs) on the crystallization kinetics of poly(ethylene oxide) (PEO) is examined. Lignin from spruce and ionic isolation was used to prepare LNPs with a number-averaged diameter of 85 nm (with a relatively large polydispersity) by an ultrasonication method. PEO-based nanocomposites with four different LNP contents (5, 10, 15, and 20 wt %) were prepared and subject to isothermal and nonisothermal crystallization protocols in a series of experiments. Scanning electron microscopy (SEM) images showed well-dispersed LNPs in the crystallized PEO matrix. The incorporation of LNPs exponentially increases nucleation density at moderate loadings, with this trend apparently saturating at higher loadings. However, the spherulitic growth rate decreases monotonically with LNP loading. This is attributed to the substantial PEO/LNP affinity, which impacts chain diffusion and induces supernucleation effect (with efficiencies in the order of 200%), but leads to slower growth rates. The overall crystallization kinetics, measured by the DSC, shows faster nanocomposite crystallization rates relative to the neat PEO at all LNP contents examined. This indicates that the supernucleation effect of LNPs dominates over the decrease in the growth rates, although its influence slightly decreases as the LNP content increases. The strong hydrogen-bonded interactions between the LNPs and the PEO are thus reminiscent of confinement effects found in polymer-grafted NP nanocomposites (e.g., PEO-g-SiO2/PEO) in the brush-controlled regime.This work received funding from the Basque Government through grant IT1503 - 22. S.K.K . acknowledges funding by the U.S. Department of Energy, Office of Science, grants DE- SC0018182, DE-SC0018135, and DE-SC0018111. The authors acknowledged the financial support of Fundacion Losano, PIP2011 848, and PUE No. 22920160100007 (CONICET) . The authors acknowledge the support of Ana Martínez Amesti, Microscopy: Polymer Characterization Research Service, SGIker (UPV/EHU)

    Antiaterogenicidad in vitro de extractos del alga marina Halimeda incrassata: actividad antioxidante y estudios de migración en células de la musculatura lisa

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    Aim: The aim of this work was to evaluate the in vitro atheroprotective potential of the seaweed Halimeda incrassata in smooth muscle cell migration and lipoprotein oxidation in relation to its antioxidant activity.Material and methods: Antioxidant activity was determinate by DPPH• radical scavenging assay and ORAC method. The inhibitory effect of the aqueous extract on LDL oxidation mediated by Cu2+ ions was determinate by TBARS and conjugated diene quantification. The effect of the seaweed aqueous extract on smooth muscle cell migration was evaluated in MOVAS-1 mouse aortic smooth muscle cell.Results: The inhibitory effect of the aqueous extract on lipoprotein oxidation mediated by Cu2+ was demonstrated. Seaweed extract caused dose-dependent inhibition of TBARS (IC50 = 0.8 mg/mL) and conjugated dienes formation. The seaweed had a high antioxidant activity in the assays performed. The activity could be related to the phenolic content of Halimeda incrassata.Conclusions: In summary, the results of this study represent a further step in the characterization of the atheroprotective action of Halimeda incrassata and indicate the seaweed could be used for a nutraceutical and/or phytoterapeutic application.Objetivos: El objetivo de este trabajo fue evaluar el potencial ateroprotector in vitro del alga Halimeda incrassata en la migración de células de músculo liso de ratón y la oxidación de lipoproteínas en relación con su actividad antioxidante.Material y métodos: La actividad antioxidante fue determinada mediante los métodos de inhibición de radicales DPPH y la Capacidad antioxidante total (ORAC). La actividad inhibitoria de la oxidación de LDL mediada por iones Cu2+ se determinó por la cuantificación de TBARS y dienos conjugados. El efecto del extracto acuoso sobre la migración de las células de músculo liso se evaluó en la línea de células de músculo liso aórtica de ratón MOVAS-1.Resultados: Se demostró el efecto inhibidor del extracto sobre la oxidación de LDL mediada por Cu2+. El extracto del alga causa inhibición dosis-dependiente de la formación de TBARS (IC50 = 0,8 mg/mL) y dienos conjugados. Las algas tuvieron una alta actividad antioxidante en los ensayos realizados y podría estar relacionada con el contenido de compuestos fenólicos.Conclusiones: Los resultados de este trabajo representan un paso más en la caracterización de la acción ateroprotectora de Halimeda incrassata y evidencian sus posibles aplicaciones como nutracéutico y/o fitofármaco
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