Estudi del comportament d'endoreactors hibrids per simulació numèrica

Les cambres de combustió per a endoreactors de tipus híbrid presenten un front de flama molt estable, una estabilitat que garanteix una seguretat intrínseca en el funcionament d'aquest tipus de motor coet, però que al mateix temps impedeix l'obtenció de prestacions competitives respecte als endoreactors sòlids i líquids utilitzats tradicionalment. En aquest TFC s'ha estudiat el disseny de geometries de la cambra de combustió que permetin augmentar l'eficiència de la combustió i la velocitat de regressió del gra de combustible sòlid. S'ha emprat el software de mallat Gambit i del de dinàmica de fluids computacional Fluent amb els qual s'han dissenyat les diferents geometries de cambra de combustió, i el posterior comportament fluidodinàmic. S'ha introduit a Fluent la cinètica de les reaccions químiques que permet simular la reacció entre un oxidant i un comburent el més proper possible als que s'utilitzen en l'actualitat

Game Space and Game Situation as Mediators of the External Load in the Tasks of School Handball

The teacher's didactic intervention also requires knowledge and control of learning tasks' workloads. The objectives of the study were as follows: (i) to quantify the subjective external load-eTL of tasks framed in didactic units designed by in-service teachers; and (ii) to analyze the differences in the subjective eTL according to the game situation and the game space. A total of 306 learning tasks designed by seven in-service teachers (five men and two women), with more than 10 years of teaching practice, were analyzed. These tasks were coded through the Integral System for Training Task Analysis (SIATE, acronym in Spanish). The interobserver reliability of the coded variables obtained a considerable concordance (MKfree > 0.70). The results indicated that there were significant differences in the subjective eTL according to the game situation and game space. The situations of small-sided games in numerical equality or inequality and full games, in medium spaces or large spaces, presented a higher subjective eTL and therefore the highest physiological and motor demands on students. The inclusion of attacking or defending players and an adequate selection of the game space indicated the importance of planning and organizing learning tasks

TÉCNICAS Y MÉTODOS DE INVESTIGACIÓN

GUÍA DE EVALUACIÓN DEL APRENDIZAJ

Relationship between soil physicochemical characteristics and nitrogen-fixing bacteria in agricultural soils of the Atlántico department, Colombia

Microbial richness of agricultural soils is an indicator of its health and fertility with a significant impact on crop yields. Present study analyzed the relationship between nitrogen-fixing bacteria and physicochemical characteristics of agricultural soils in the southern department of Atlántico, Colombia. Soil samples were collected from 10 sites of Repelón irrigation district, for physicochemical analysis (pH, organic matter, texture, moisture and available phosphorus) and isolation of nitrogen-fixing bacterial’ strains using nitrogen-free culture media. Results demostrated the higher previlance of nitrogen–fixing bacteria in northern zone and central zone of the Repelón irrigation district (1.63 × 108 CFU g-1 for strain-1, 5.2 × 107 CFU g-1 for strain-2 and 4.5 × 107 CFU g-1 for strain-3). On the other hand, the physicochemical characteristics of soil show the adequacy to sustain nitrogen-fixing bacteria. The findings of the present research may serve as a baseline to identify soil micorganisms and defining strategies for sustainable management of agricultural soils in the region because these are integral component in ecosystem for nutrient recycling. © 2017, Soil Science Society of Pakista

Specific Preferences in Lineage Choice and Phenotypic Plasticity of Glioma Stem Cells Under BMP4 and Noggin Influence

Although BMP4-induced differentiation of glioma stem cells (GSCs) is well recognized, details of the cellular responses triggered by this morphogen are still poorly defined. In this study, we established several GSC-enriched cell lines (GSC-ECLs) from high-grade gliomas. The expansion of these cells as adherent monolayers, and not as floating neurospheres, enabled a thorough study of the phenotypic changes that occurred during their differentiation. Herein, we evaluated GSC-ECLs' behavior toward differentiating conditions by depriving them of growth factors and/or by adding BMP4 at different concentrations. After analyzing cellular morphology, proliferation and lineage marker expression, we determined that GSC-ECLs have distinct preferences in lineage choice, where some of them showed an astrocyte fate commitment and others a neuronal one. We found that this election seems to be dictated by the expression pattern of BMP signaling components present in each GSC-ECL. Additionally, treatment of GSC-ECLs with the BMP antagonist, Noggin, also led to evident phenotypic changes. Interestingly, under certain conditions, some GSC-ECLs adopted an unexpected smooth muscle-like phenotype. As a whole, our findings illustrate the wide differentiation potential of GSCs, highlighting their molecular complexity and paving a way to facilitate personalized differentiating therapies.Fil: Videla Richardson, Guillermo Agustín. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; ArgentinaFil: Garcia, Carolina Paola. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Roisman, Alejandro. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Slavutsky, Irma Rosa. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Fernandez Espinosa, Damian Dario. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; ArgentinaFil: Romorini, Leonardo. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Miriuka, Santiago Gabriel. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Arakaki, Naomi. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; ArgentinaFil: Martinetto, Horacio Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Scassa, Maria Elida. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; ArgentinaFil: Sevlever, Gustavo Emilio. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; Argentin

Ferulic acid-loaded polymeric nanoparticles prepared from nano-emulsion templates facilitate internalisation across the blood?brain barrier in model membranes

Ferulic acid-loaded PLGA NPs were synthesised via low-energy emulsification methods utilising nano-emulsion templating including permeabilisation efficiency assessed using an in vitro organ-on-a-chip system that simulates the blood-brain barrier