Relevancia de la técnica de inmovilización de brazos en las variables cinéticas en el test de salto con contramovimiento

The countermovement jump test (CMJ) has become one of the most widely used methods for assessing the power of the lower body. When carrying it out correctly, the action of the upper extremities must be maximally isolated, so that strength production comes exclusively from the lower body. In the specific bibliography, several ways to limit the arm action have been proposed, and having the hands on the hips is the most common. The question arises as to whether the use of one technique or another could influence the performance of the jump, which would question the possibility of comparing different studies’ results. In the present study, 19 participants performed four different techniques of the CMJ: free arms motion, holding forearms behind the back, hands on the hips, and holding a plastic stick on the shoulders. Commonly measured kinetic variables of the jump have been analysed and compared in order to determine whether the arm position is a factor that influences the test results. As expected, significant differences were found between the techniques using the help of the arms and the other techniques (p < 0.05). However, there were no significant differences between the three arm immobilization techniques. This leads to the conclusion that the arm position is not decisive, making it possible to compare the results obtained from the different published studiesEl test de salto vertical con contramovimiento (CMJ) se ha venido conformando como uno de los métodos de evaluación de la potencia del tren inferior más utilizado. A la hora de ejecutarlo de forma correcta, se debe aislar al máximo la acción de las extremidades superiores, con el fin de que la producción de fuerza provenga exclusivamente del tren inferior. En la bibliografía específica se han propuesto diversas formas de limitar la acción de los brazos, siendo la más frecuente con las manos en la cintura. Cabe preguntarse si el uso de una técnica u otra podría influir en el rendimiento del salto, lo que no permitiría comparar entre diferentes estudios. Participó una muestra de 19 sujetos que realizó cuatro técnicas diferentes de colocación de los brazos en CMJ: con acción de brazos libre; agarre de antebrazos por detrás de la espalda; manos en la cintura; y agarre de una pica de plástico sobre los hombros. Se analizaron y compararon las principales variables cinemáticas en el salto con el fin de determinar si la posición de los brazos es un factor que condiciona los resultados de los test. Como cabía esperar, se aprecian diferencias significativas con ayuda de brazos respecto a las otras técnicas (p < 0.05). Sin embargo, no se aprecian diferencias significativas entre las tres técnicas de inmovilización de brazos planteadas. Esto lleva a concluir que no es determinante la posición de brazos utilizada, por lo que es posible comparar los resultados obtenidos en los distintos estudios publicadosActividad Física y Deport

Electrodeposited Ni-rich Ni-Pt mesoporous nanowires for selective and efficient formic acid-assisted hydrogenation of levulinic acid to γ-valerolactone

In pursuit of friendlier conditions for the preparation of high-value biochemicals, we developed a catalytic synthesis of -valerolactone by levulinic acid hydrogenation with formic acid as the hydrogen source. Both levulinic and formic acid are intermediate products in the biomass transformation processes. The objective of the work is two-fold; development of a novel approach for milder synthesis conditions to produce -valerolactone and the reduction of the economic cost of the catalyst. Ni-rich Ni-Pt mesoporous nanowires were synthesized in an aqueous medium using a combined hard-soft template-assisted electrodeposition method, in which porous polycarbonate membranes controlled the shape, and the pluronic P-123 copolymer served as the porogen agent. The electrodeposition conditions selected favored nickel deposition and generated nanowires with nickel percentages above the 75 at. %. The increase in deposition potential favored nickel deposition. However, it was detrimental for the porous diameter, because the mesoporous structure is promoted by the presence of the platinum-rich micelles near the substrate, which is not favored at the more negative potentials. The prepared catalysts promoted the complete transformation to -valerolactone in a yield of around 99% and proceeded with the absence of by-products. The couple temperature and reaction time were optimized considering the energy cost. The threshold operational temperature was established at 140 ºC, at which, 120 minutes were sufficient for attaining the complete transformation. Working temperatures below 140 ºC rendered the reaction completion difficult. The Ni78Pt22 nanowires exhibited excellent reusability, with minimal nickel leaching into the reaction mixture, whereas those with higher nickel contents showed corrosion

Optimización de modelos en elementos finitos de los maniquíes Hybrid-III percentiles 50% y 95% para su aplicación en transporte ferroviario

En este artículo se presenta la metodología seguida para el desarrollo de los modelos matemáticos de los maniquíes Hybrid-III 50% y 95%, los cuales son capaces de predecir correctamente los criterios de lesión asociados a cada región del cuerpo. Como aplicación práctica de los modelos, se evalúa la seguridad de butacas de tren mediante técnicas de simulación. En primer lugar se han desarrollado los modelos a través de su geometría tridimensional. También han sido asignados los diferentes materiales y propiedades de cada parte de los maniquíes. Posteriormente se ha seguido un proceso de optimización y de mejora que incluye la verificación y validación de los maniquíes virtuales. Dicha validación se realiza a partir de los maniquíes físicos y de los datos experimentales que posee el Laboratorio de Seguridad Pasiva (LSP) del INSIA de la UPM, utilizando los maniquíes en varias configuraciones. Finalmente, se realiza el proceso de optimización de estos modelos virtuales para que representen lo más fielmente posible la realidad, que su comportamiento sea preciso y que el tiempo de cálculo o coste computacional sea el menor posible. Una vez creados los modelos en elementos finitos de ambos maniquíes, se emplean para analizar la seguridad de las butacas de tren mediante la simulación de los ensayos dinámicos que se describen en la norma GM/RT2100. Esta norma exige dos configuraciones de ensayo para evaluar la seguridad de las butacas. La primera configuración sirve para evaluar la resistencia y la integridad estructural de la butaca y sus anclajes mediante el uso de dos maniquíes Hybrid-III 95%. La segunda configuración se utiliza para evaluar la protección que las butacas ofrecen al ocupante mediante el uso de un maniquí Hybrid-III 50% instrumentado. En ambas configuraciones se realizan impactos en sentido de la marcha y en el sentido contrario y se compran los valores registrados en los maniquíes tanto en los ensayos reales como en las simulaciones matemáticas

Electrodeposition of mesoporous Ni-rich Ni-Pt films for highly efficient methanol oxidation

The use of soft templates for the electrosynthesis of mesoporous materials has shown tremendous potential in energy and environmental domains. Among all the approaches that have been featured in the literature, block copolymer-templated electrodeposition had robustness and a simple method, but it practically cannot be used for the synthesis of mesoporous materials not based on Pt or Au. Nonetheless, extending and understanding the possibilities and limitations of block copolymer-templated electrodeposition to other materials and substrates is still challenging. Herein, a critical analysis of the role of the solution's primary electroactive components and the applied potential were performed in order to understand their influences on the mesostructure of Ni-rich Ni-Pt mesoporous films. Among all the components, tetrahydrofuran and a platinum (IV) complex were shown to be crucial for the formation of a truly 3D mesoporous network. The electrosynthesized well-ordered mesoporous Ni-rich Ni-Pt deposits exhibit excellent electrocatalytic performance for methanol oxidation in alkaline conditions, improved stability and durability after 1000 cycles, and minimal CO poisoning

Simple environmentally-friendly reduction of 4-nitrophenol

Abstract: 4-nitrophenol is a low molecular-mass organic compound involved in many chemical processes and commonly present in soils and in surface and ground waters, thereby causing severe environmental impact and health risk. Several methods have been proposed for its transformation (bio and chemical degradation). However, these strategies not only produce equally or more toxic aromatic species but also require harsh operating conditions and/or time-consuming treatments. In this context, we report a comprehensive and systematic study of the electrochemical reduction of 4-nitrophenol as a viable alternative. We have explored the electrochemical reduction of this pollutant over different metallic and carbonaceous substrata. Specifically, we have focused on the use of gold and silver working electrodes since they combine a high electrocatalytic activity for 4-nitrophenol reduction and a low electrocatalytic capacity for hydrogen evolution. The influence of the pH, temperature, and applied potential have also been considered as crucial parameters in the overall optimization of the process. While acidic media and high temperatures favor the clean reduction of 4-nitrophenol to 4-aminophenol, simultaneous hydrogen evolution results pernicious for this purpose. As a whole, a simple and effective electrochemical method for the transformation of 4-nitrophenol into 4-aminophenolis proposed with virtually no undesired by-products

Electrochemical growth of CoNi and Pt-CoNi soft magnetic composites on an alkanethiol monolayer-modified ITO substrate

CoNi and Pt-CoNi magnetic layers on indium-tin oxide (ITO) substrates modified by an alkanethiol self-assembled monolayer (SAM) have been electrochemically obtained as an initial stage to prepare semiconducting layer-SAM-magnetic layer hybrid structures. The best conditions to obtain the maximum compactness of adsorbed layers of dodecanethiol (C12-SH) on ITO substrate have been studied using contact angle, AFM, XPS and electrochemical tests. The electrochemical characterization (electrochemical probe or voltammetric response in blank solutions) is fundamental to ensure the maximum blocking of the substrate. Although the electrodeposition process on the SAM-modified ITO substrate is very slow if the blocking of the surface is significant, non-cracked metallic layers of CoNi, with or without a previously electrodeposited seed-layer of platinum, have been obtained by optimizing the deposition potentials. Initial nucleation is expected to take place at the pinhole defects of the C12-SH SAM, followed by a mushroom-like growth regime through the SAM interface that allows the formation of a continuous metallic layer electrically connected to the ITO surface. Due to the potential of the methodology, the preparation of patterned metallic deposits on ITO substrate using SAMs with different coverage as templates is feasible

Inactivation of the waterborne pathogen Cryptosporidium parvum by photo-Fenton process under natural solar conditions

Cryptosporidiumis an important genus of emerging enteropathogens responsible for waterborne outbreaksworldwide. This parasite has a robust infective form (oocyst), which is highly resistant to the environmentalconditions and to the conventional disinfection treatments of water. This work evaluates for thefirst time thephoto-Fenton process againstCryptosporidium parvum.For that, a factorial design was used to study the com-bined effects of the Fe2+/H2O2concentration (5/10, 10/20 and 20/50 mg L−1), pH (3, 5.5 and 8) and exposuretime (2, 4 and 6 h) on the oocyst survival in distilled water under natural sunlight. The oocyst viability wasdetermined by inclusion/exclusion of thefluorogenic vital dye propidium iodide. The variables Fe2+/H2O2concentration and exposure time showed statistically significant effects on the oocyst viability, as did the in-teraction of pH with Fe2+/H2O2concentration. The maximum oocyst inactivation rates corresponded to thecombination of the highest concentration of Fe2+/H2O2(20/50 mg L−1), the lowest pH value (3) and longestexposure times (4 and 6 h) (3.68 ± 1.38% and 6.39 ± 2.65%, respectively,vs91.67 ± 3.63%, initial oocystviability). Although further studies are needed to evaluate the influence of the water matrix and optimize thephoto-Fenton process, the results obtained demonstrate the efficacy of this advanced oxidation process againstC.parvumoocysts. The inactivation of this enteropathogen would probably ensure elimination of other less re-sistant infectious agents, providing an appropriate protection for the environment and, consequently, for humanand animal healthThis Special Issue is dedicated to honor the retirement of Prof. CésarPulgarin at the Swiss Federal Institute of Technology (EPFL,Switzerland), a keyfigure in the area of Catalytic Advanced OxidationProcesses. This work was supported by the European Union ́s Horizon2020 Research and Innovation [grant number 688928]S

Control of dissipation in superconducting films by magnetic stray fields

Hybrid superconducting/magnetic nanostructures on Si substrates have been built with identical physical dimensions but different magnetic configurations. By constructing arrays based on Co-dots with in-plane, out-of-plane, and vortex state magnetic configurations, the stray fields are systematically tuned. Dissipation in the mixed state of superconductors can be decreased (increased) by several orders of magnitude by decreasing (increasing) the stray magnetic fields. Furthermore, ordering of the stray fields over the entire array helps to suppress dissipation and enhance commensurability effects increasing the number of dissipation minima

Active nanocomposite films based on soy proteins-montmorillonite- clove essential oil for the preservation of refrigerated bluefin tuna (Thunnus thynnus) fillets

This manuscript evaluates the potential application of active nanocomposite films based on soy protein isolate (SPI)-montmorillonite (MMT)-clove essential oil (CEO) to the preservation of muscle fillets of bluefin tuna (Thunnus thynnus) during refrigerated storage, and furthermore analyzes whether the clay diffuses from the package to food. SPI films with: CEO (SPI-CEO), MMT (SPI-MMT), or both CEO and MMT (SPI-MMT-CEO), were prepared and used to cover tuna fillets during 17 days of storage at 2 °C. Polyethylene films were also used as control. Protein films nanoreinforced with 10 g MMT/100 g SPI and activated with CEO were able to decrease microbial growth (evaluated by TVBN and microorganism counts) and lipid autooxidation (evaluated according to the TBA index, FTIR and color parameters) of tuna fillets during the storage period studied. The presence of clay seemed to favor the release of the active principles of clove oil by prolonging its antimicrobial (especially effective to inhibit Pseudomonas spp.) and antioxidant activity over time without observing the diffusion of the clay's own metals (Si and Al) from the nanocomposite materials to the muscle of fish. These results are encouraging for the use of nanocomposite films in food packaging.Fil: Echeverría, Ignacio. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; ArgentinaFil: López Caballero, María Elvira. Consejo Superior de Investigaciones Científicas. Instituto de Ciencia y Tecnologia de Alimentos y Nutrición; EspañaFil: Gómez Guillén, María Carmen. Consejo Superior de Investigaciones Científicas. Instituto de Ciencia y Tecnologia de Alimentos y Nutrición; EspañaFil: Mauri, Adriana Noemi. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Montero, María Pilar. Consejo Superior de Investigaciones Científicas. Instituto de Ciencia y Tecnologia de Alimentos y Nutrición; Españ

Active nanocomposite films based on soy proteins-montmorillonite- clove essential oil for the preservation of refrigerated bluefin tuna (Thunnus thynnus) fillets

This manuscript evaluates the potential application of active nanocomposite films based on soy protein isolate (SPI)-montmorillonite (MMT)-clove essential oil (CEO) to the preservation of muscle fillets of bluefin tuna (Thunnus thynnus) during refrigerated storage, and furthermore analyzes whether the clay diffuses from the package to food. SPI films with: CEO (SPI-CEO), MMT (SPI-MMT), or both CEO and MMT (SPI-MMT-CEO), were prepared and used to cover tuna fillets during 17 days of storage at 2 °C. Polyethylene films were also used as control. Protein films nanoreinforced with 10 g MMT/100 g SPI and activated with CEO were able to decrease microbial growth (evaluated by TVBN and microorganism counts) and lipid autooxidation (evaluated according to the TBA index, FTIR and color parameters) of tuna fillets during the storage period studied. The presence of clay seemed to favor the release of the active principles of clove oil by prolonging its antimicrobial (especially effective to inhibit Pseudomonas spp.) and antioxidant activity over time without observing the diffusion of the clay's own metals (Si and Al) from the nanocomposite materials to the muscle of fish. These results are encouraging for the use of nanocomposite films in food packaging.Centro de Investigación y Desarrollo en Criotecnología de Alimento