233 research outputs found
Low molecular weight ϵ-caprolactone-pcoumaric acid copolymers as potential biomaterials for skin regeneration applications
ϵ-caprolactone-p-coumaric acid copolymers at different mole ratios (ϵ-caprolactone:p-coumaric acid 1:0, 10:1, 8:1, 6:1, 4:1, and 2:1) were synthesized by melt-polycondensation and using 4-dodecylbenzene sulfonic acid as catalyst. Chemical analysis by NMR and GPC showed that copolyesters were formed with decreasing molecular weight as p-coumaric acid content was increased. Physical characteristics, such as thermal and mechanical properties, as well as water uptake and water permeability, depended on the mole fraction of pcoumaric acid. The p-coumarate repetitive units increased the antioxidant capacity of the copolymers, showing antibacterial activity against the common pathogen Escherichia coli. In addition, all the synthesized copolyesters, except the one with the highest concentration of the phenolic acid, were cytocompatible and hemocompatible, thus becoming potentially useful for skin regeneration applications
An Evolutionary Study of Carex Subg. Psyllophorae (Cyperaceae) Sheds Light on a Strikingly Disjunct Distribution in the Southern Hemisphere, With Emphasis on Its Patagonian Diversification
Carex subgenus Psyllophorae is an engaging study group due to its early diversification compared to most Carex lineages, and its remarkable disjunct distribution in four continents corresponding to three independent sections: sect. Psyllophorae in Western Palearctic, sect. Schoenoxiphium in Afrotropical region, and sect. Junciformes in South America (SA) and SW Pacific. The latter section is mainly distributed in Patagonia and the Andes, where it is one of the few Carex groups with a significant in situ diversification. We assess the role of historical geo-climatic events in the evolutionary history of the group, particularly intercontinental colonization events and diversification processes, with an emphasis on SA. We performed an integrative study using phylogenetic (four DNA regions), divergence times, diversification rates, biogeographic reconstruction, and bioclimatic niche evolution analyses. The crown age of subg. Psyllophorae (early Miocene) supports this lineage as one of the oldest within Carex. The diversification rate probably decreased over time in the whole subgenus. Geography seems to have played a primary role in the diversification of subg. Psyllophorae. Inferred divergence times imply a diversification scenario away from primary Gondwanan vicariance hypotheses and suggest long-distance dispersal-mediated allopatric diversification. Section Junciformes remained in Northern Patagonia since its divergence until Plio-Pleistocene glaciations. Andean orogeny appears to have acted as a northward corridor, which contrasts with the general pattern of North-to-South migration for temperate-adapted organisms. A striking niche conservatism characterizes the evolution of this section. Colonization of the SW Pacific took place on a single long-distance dispersal event from SA. The little ecological changes involved in the trans-Pacific disjunction imply the preadaptation of the group prior to the colonization of the SW Pacific. The high species number of the section results from simple accumulation of morphological changes (disparification), rather than shifts in ecological niche related to increased diversification rates (radiation).Fil: Benítez Benítez, Carmen. Universidad Pablo de Olavide; EspañaFil: Otero, Ana. Field Museum of Natural History; Estados UnidosFil: Ford, Kerry A.. Manaaki-Whenua Landcare Research; Nueva ZelandaFil: García Moro, Pablo. Universidad Autónoma de Madrid; EspañaFil: Donadío, Sabina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; ArgentinaFil: Luceño, Modesto. Universidad Pablo de Olavide; EspañaFil: Martín Bravo, Santiago. Universidad Pablo de Olavide; EspañaFil: Jiménez-Mejías, Pedro. Universidad Autónoma de Madrid; Españ
El patrimonio universitario como laboratorio vivo para el implemento de técnicas y procesos tradicionales de restauración
La Benemérita Universidad Autónoma de Puebla, es una institución con alto prestigio a nivel nacional que se ha caracterizado por los grandes logros que ha alcanzado en sus diferentes disciplinas. Dentro de sus principales misiones, está el preservar y conservar el amplio patrimonio que lo ha identificado. Bajo este fundamento, la Facultad de Arquitectura desarrolla el proyecto de restauración de uno de los inmuebles pertenecientes al gran acervo que le pertenece a la universidad, en la Ciudad de Puebla, ciudad que cuenta con gran valor cultural debido a la gran diversidad patrimonial con que cuenta, como lo afirma Anon (2012). Este trabajo se proyecta para albergar la Mapoteca Digital Universitaria de la actual Mapoteca Jorge A. Vivo Escoto. El desarrollo de este proyecto, realizado bajo la metodología de los sistemas complejos, permitió mejorar la dinámica educativa haciendo del inmueble analizado un laboratorio vivo, en donde además de poner en práctica los conocimientos adquirido en el aula, logra el implemento práctico de las técnicas y los procesos constructivos tradicionales que fueron empleados en edificios históricos. Desde el primer contacto que se tuvo con el inmueble, se llevaron a cabo acciones preliminares para poder ingresar al edificio y poder desarrollar los estudios necesarios. Otras de las prácticas implementadas fueron realizadas en talleres aplicados dentro del inmueble analizado, con el fin de acercarse al conocimiento de los materiales de fábrica, así como su manejo, implementación y difusión en la práctica de la restauració
Valorization of Tomato Processing by-Products: Fatty Acid Extraction and Production of Bio-Based Materials
A method consisting of the alkaline hydrolysis of tomato pomace by-products has been optimized to obtain a mixture of unsaturated and polyhydroxylated fatty acids as well as a non-hydrolysable secondary residue. Reaction rates and the activation energy of the hydrolysis were calculated to reduce costs associated with chemicals and energy consumption. Lipid and non-hydrolysable fractions were chemically (infrared (IR) spectroscopy, gas chromatography/mass spectrometry (GC-MS)) and thermally (differential scanning calorimetry (DSC), thermogravimetric analysis (TGA)) characterized. In addition, the fatty acid mixture was used to produce cutin-based polyesters. Freestanding films were prepared by non-catalyzed melt-polycondensation and characterized by Attenuated Total Reflected-Fourier Transform Infrared (ATR-FTIR) spectroscopy, solid-state nuclear magnetic resonance (NMR), DSC, TGA, Water Contact Angles (WCA), and tensile tests. These bio-based polymers were hydrophobic, insoluble, infusible, and thermally stable, their physical properties being tunable by controlling the presence of unsaturated fatty acids and oxygen in the reaction. The participation of an oxidative crosslinking side reaction is proposed to be responsible for such modifications.Andalusian Regional Government P11-TEP-7418Spanish Ministerio de Economía y Competitividad AGL2015-65246-R and AGL2017-83036-RFondo Europeo de Desarrollo Regional (FEDER) AGL2015-65246-R and AGL2017-83036-
Production of microalgal external organic matter in a Chlorella-dominated culture: influence of temperature and stress factors
Although microalgae are recognised to release external organic matter (EOM), little is known about this phenomenon in microalgae cultivation systems, especially on a large scale. A study on the effect of microalgae-stressing factors such as temperature, nutrient limitation and ammonium oxidising bacteria (AOB) competition in EOM production by microalgae was carried out. The results showed non-statistically significant differences in EOM production at constant temperatures of 25, 30 and 35 °C. However, when the temperature was raised from 25 to 35 °C for 4 h a day, polysaccharide production increased significantly, indicating microalgae stress. Nutrient limitation also seemed to increase EOM production. No significant differences were found in EOM production under lab conditions when the microalgae competed with AOB for ammonium uptake. However, when the EOM concentration was monitored during continuous outdoor operation of a membrane photobioreactor (MPBR) plant, nitrifying bacteria activity was likely to be responsible for the increase in EOM concentration in the culture. Other factors such as high temperatures, ammonium-depletion and low light intensities could also have induced cell deterioration and thus have influenced EOM production in the outdoor MPBR plant. Membrane fouling seemed to depend on the biomass concentration of the culture. However, under the operating conditions tested, the behaviour of fouling rate with respect to the EOM concentration was different depending on the initial membrane state
Jump Performance after Different Friendly Matches Played on Consecutive Days
Los objetivos del estudio fueron determinar el cambio en la altura alcanzada en el salto con contramovimiento (CMJ) tras tres partidos amistosos jugados en días consecutivos, y evaluar si existe una asociación significativa entre los cambios en la altura del CMJ respecto a los minutos disputados y los valores de percepción subjetiva del esfuerzo (RPE). La altura de salto de 22 jóvenes futbolistas varones (edad: 16,6+/-0,8 años) fue determinada en 5 ocasiones: Pre-viaje, Pre-partido 1, Pre-partido 2, Pre-partido 3, y Post-viaje. Los resultados mostraron una reducción de la altura de salto respecto al pre-viaje (P<0,001; tamaño de efecto ≥ 1.47), mientras que el cambio en la altura de salto no estuvo significativamente correlacionado con los minutos disputados (r=-0.02; P=0.464) ni con la RPE (r=0.15; P=0.249). La sucesión de partidos de fútbol provoca una disminución en la altura de salto que no está relacionada con los minutos disputados ni la RPE.The aims of the study were to determine the change in countermovement jump (CMJ) after three friendly matches played on consecutive days, and to evaluate if there is a significant correlation between the changes observed in CMJ height with respect to the minutes played and the rate of perceived exertion (RPE) values. The CMJ height of 22 young male soccer players (age: 16.6±0.8 years) was determined in 5 occasions: pre-trip, pre-game 1, pre-game 2, pre-game 3, and post-trip. The results showed a reduction in jump height when compared to the pre-trip (P<0,001; effect size ≥ 1.47), while the change in jump height was not significantly correlated with the minutes played r=-0.02; P=0.464) nor with the RPE values (r=0.15; P=0.249). The succession of football matches promotes a decrease in jump height that is not related to the minutes played nor to the RPE values
Chemical-physical characterization of isolated plant cuticles subjected to low-dose γ-irradiation
Isolated tomato fruit cuticles were subjected to low dose (80 Gy) γ-irradiation, as a potential methodology to prevent harvested fruit and vegetables spoilage. Both irradiated and non-irradiated samples have been morphologically and chemically characterized by scanning electron (SEM), atomic force (AFM), attenuated total reflectance Fourier transform infrared (ATR-FTIR) and X-ray photoelectron (XPS) spectroscopies. Additionally, electrochemical measurements comprising membrane potential and diffusive permeability were carried out to detect modifications in transport properties of the cuticle as the fruit primary protective membrane. It has been found that low dose γ-irradiation causes some textural changes on the surface but no significant chemical modification. Texture modification is found to be due to a partial removal of outermost (epicuticular) waxes which is accompanied by mild changes of electrochemical parameters such as the membrane fixed charge, cation transport number and salt permeability. The modification of such parameters indicates a slight reduction of the barrier properties of the cuticle upon low dose γ-irradiation.
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