Utilization of Wood Flour from White Oak Branches as Reinforcement in a Polypropylene Matrix: Physical and Mechanical Characterization

Compared to other fibrous materials, plant fibers can act as a reinforcement in plastics due to their relatively high strength and rigidity, low cost, low density, biodegradability, and renewability. In this context, this study examines the effect of the particle size and content of white oak wood flour (Quercus laeta Liemb), obtained from its branches, on the properties of commercial polypropylene. In Mexico, wood from the branches of Quercus laeta Liemb is barely utilized despite its abundance and viability. The main objective of this study is to demonstrate that this waste material can be exploited to prepare useful materials, in this case composites with competitive properties. Tensile and flexural tests, as well as impact strength and melt flow index were evaluated. In addition, density and water absorption capacity were also tested. Results showed that the water absorption increased with the incorporation of wood particles. Mechanical properties were strongly influenced by particle content. A reduction in elongation and strength was observed, while Young’s modulus and flexural modulus increased with the incorporation of wood particles. Impact strength increased with particle size and particle content

Utilization of Wood Flour from White Oak Branches as Reinforcement in a Polypropylene Matrix: Physical and Mechanical Characterization

Compared to other fibrous materials, plant fibers can act as a reinforcement in plastics due to their relatively high strength and rigidity, low cost, low density, biodegradability, and renewability. In this context, this study examines the effect of the particle size and content of white oak wood flour (Quercus laeta Liemb), obtained from its branches, on the properties of commercial polypropylene. In Mexico, wood from the branches of Quercus laeta Liemb is barely utilized despite its abundance and viability. The main objective of this study is to demonstrate that this waste material can be exploited to prepare useful materials, in this case composites with competitive properties. Tensile and flexural tests, as well as impact strength and melt flow index were evaluated. In addition, density and water absorption capacity were also tested. Results showed that the water absorption increased with the incorporation of wood particles. Mechanical properties were strongly influenced by particle content. A reduction in elongation and strength was observed, while Young’s modulus and flexural modulus increased with the incorporation of wood particles. Impact strength increased with particle size and particle content

Antifungal Activity of <i>Datura stramonium</i> L. Extractives against Xylophagous Fungi

Some plants have great resistance against herbivores, invertebrates, insects, bacteria, and fungi. This resistance is mostly present in plants containing alkaloids, which are the substances responsible for giving them defensive properties. The genus Datura contains tropane alkaloids and all plants from this genus have defensive properties. In this work, we report the toxic effect against fungi of Datura stramonium extracts, obtained by the Petri dish method. The extraction solvents were water, ethanol, 2-propanol, n-butanol, propanone, butanone, 3-methyl-2-pentanone, dichloromethane, xylene, and toluene. The test fungi were Trametes versicolor (L. ex. Fr) Pilát and Rhodonia placenta (Fr.) Niemelä, K.H.Larss. & Schigel. It was found that water, butanone, and toluene extracts promoted mycelial growth, xylene extracts neither inhibited nor promoted mycelial growth, while the other extracts slightly inhibited the growth of these fungi

Physicomechanical and Morphological Characterization of Multi-Structured Potassium-Acrylate-Based Hydrogels

In this work, a photo-polymerization route was used to obtain potassium acrylate-co-acrylamide hydrogels with enhanced mechanical properties, well-defined microstructures in the dry state, and unique meso- and macrostructures in the hydrated state. The properties of the hydrogels depended on the concentration of the crosslinking agent. Mechanical properties, swelling capacity, and morphology were analyzed, showing a well-defined transition at a critical concentration of the crosslinker. In terms of morphology, shape-evolving surface patterns appeared at different scales during swelling. These surface structures had a noticeable influence on the mechanical properties. Hydrogels with structures exhibited better mechanical properties compared to unstructured hydrogels. The critical crosslinking concentration reported in this work (using glycerol diacrylate) is a reference point for the future preparation of multistructured acrylic hydrogel with enhanced properties

Effect of curcuminoids and curcumin derivate products on thioredoxin-glutathione reductase from Taenia crassiceps cysticerci. Evidence suggesting a curcumin oxidation product as a suitable inhibitor.

Curcuma is a traditional ingredient of some Eastern cuisines, and the spice is heralded for its antitumoral and antiparasitic properties. In this report, we examine the effect of the curcuminoides which include curcumin, demethoxycurcumin (DMC) and bis-demethoxycurcumin (BDMC), as well as curcumin degradation products on thioredoxin glutathione reductase from Taenia crassiceps cysticerci Results revealed that both DMC and BDMC were inhibitors of TGR activity in the micromolar concentration range. By contrast, the inhibitory ability of curcumin was a time-dependent process. Kinetic and spectroscopical evidence suggests that an intermediary compound of curcumin oxidation, probably spiroepoxide, is responsible. Preincubation of curcumin in the presence of NADPH, but not glutathione disulfide (GSSG), resulted in the loss of its inhibitory ability, suggesting a reductive stabilizing effect. Similarly, preincubation of curcumin with sulfhydryl compounds fully protected the enzyme from inhibition. Degradation products were tested for their inhibitory potential, and 4-vinylguaiacol was the best inhibitor (IC50 = 12.9 μM), followed by feruloylmethane (IC50 = 122 μM), vanillin (IC50 = 127 μM), and ferulic aldehyde (IC50 = 180 μM). The acid derivatives ferulic acid (IC50 = 465 μM) and vanillic acid (IC50 = 657 μM) were poor inhibitors. On the other hand, results from docking analysis revealed a common binding site on the enzyme for all the compounds, albeit interacting with different amino acid residues. Dissociation constants obtained from the docking were in accord with the inhibitory efficiency of the curcumin degradation products

Correction: Effect of curcuminoids and curcumin derivate products on thioredoxin-glutathione reductase from Taenia crassiceps cysticerci. Evidence suggesting a curcumin oxidation product as a suitable inhibitor.

[This corrects the article DOI: 10.1371/journal.pone.0220098.]

Thermoplastic Starch Biocomposite Films Reinforced with Nanocellulose from <i>Agave tequilana</i> Weber var. Azul Bagasse

In this work, cellulose nanocrystals (CNCs), bleached cellulose nanofibers (bCNFs), and unbleached cellulose nanofibers (ubCNFs) isolated by acid hydrolysis from Agave tequilana Weber var. Azul bagasse, an agro-waste from the tequila industry, were used as reinforcements in a thermoplastic starch matrix to obtain environmentally friendly materials that can substitute contaminant polymers. A robust characterization of starting materials and biocomposites was carried out. Biocomposite mechanical, thermal, and antibacterial properties were evaluated, as well as color, crystallinity, morphology, rugosity, lateral texture, electrical conductivity, chemical identity, solubility, and water vapor permeability. Pulp fibers and nanocelluloses were analyzed via SEM, TEM, and AFM. The water vapor permeability (WVP) decreased by up to 20.69% with the presence of CNCs. The solubility decreases with the presence of CNFs and CNCs. The addition of CNCs and CNFs increased the tensile strength and Young’s modulus and decreased the elongation at break. Biocomposites prepared with ubCNF showed the best tensile mechanical properties due to a better adhesion with the matrix. Images of bCNF-based biocomposites demonstrated that bCNFs are good reinforcing agents as the fibers were dispersed within the starch film and embedded within the matrix. Roughness increased with CNF content and decreased with CNC content. Films with CNCs did not show bacterial growth for Staphylococcus aureus and Escherichia coli. This study offers a new theoretical basis since it demonstrates that different proportions of bleached or unbleached nanofibers and nanocrystals can improve the properties of starch films

Diálogo Regional de Política de América Latina y el Caribe: Retos y oportunidades en adaptación al cambio climático en materia de agua: Elementos para una agenda regional

El presente documento representa un esfuerzo coordinado entre varias instituciones y organizaciones de la región de América Latina y el Caribe por plasmar los resultados de una reflexión conjunta sobre el tema de la adaptación al cambio climático en la comunidad hídrica y en el marco de un Diálogo Regional de Política. El propósito principal de este Diálogo es el de dar a conocer una serie de mensajes claves y recomendaciones que permitan definir de manera informada las políticas públicas pertinentes y sus acciones correspondientes al cambio climático. Los resultados del Diálogo hasta el día de hoy se han plasmado en la presente versión del documento, que se presentará en el marco de los Diálogos por el Agua y el Cambio Climático, un evento asociado a la COP16 en Cancún, México.Cambio climático, Gestión de recursos hídricos, Administración pública y definición de políticas, cambio climático, COP-16, agua

VIII Semana de la Facultad de Educación : Desafíos de las pedagogías, las prácticas y las perspectivas investigativas en el siglo XXI.

Estas memorias de la viii Semana de la Educación Desafíos de las pedagogías, las prácticas y las perspectivas investigativas en el siglo XXI, publicadas por la editorial de la Corporación Universitaria Minuto de Dios (uniminuto), contienen las ponencias, los talleres y los foros sobre las tendencias actuales de la pedagogía, las prácticas y la investigación que desarrollan los maestros y estudiantes de licenciaturas en las instituciones educativas a nivel preescolar, básica, media y superior. Son ponencias con carácter innovador e incluyente, que responden a los retos actuales de la sociedad y que conducen a la mejora de las condiciones de formación de los ciudadanos que requiere el país, dadas las particularidades de pluralismo propias de nuestras regiones. Durante el encuentro, también se compartieron experiencias artísticas, culturales y deportivas