31 research outputs found
Redox activity as a powerful strategy to tune magnetic and/or conducting properties in benzoquinone-based metal-organic frameworks
Multifunctional molecular materials have attracted material scientists for several years as they are promising materials for the future generation of electronic devices. Careful selection of their molecular building blocks allows for the combination and/or even interplay of different physical properties in the same crystal lattice. Incorporation of redox activity in these networks is one of the most appealing and recent synthetic strategies used to enhance magnetic and/or conducting and/or optical properties. Quinone derivatives are excellent redox-active linkers, widely used for various applications such as electrode materials, flow batteries, pseudo-capacitors, etc. Quinones undergo a reversible two-electron redox reaction to form hydroquinone dianions via intermediate semiquinone radical formation. Moreover, the possibility to functionalize the six-membered ring of the quinone by various substituents/functional groups make them excellent molecular building blocks for the construction of multifunctional tunable metal-organic frameworks (MOFs). An overview of the recent advances on benzoquinone-based MOFs, with a particular focus on key examples where magnetic and/or conducting properties are tuned/switched, even simultaneously, by playing with redox activity, is herein envisioned
Metal-Organic Framework vs. Coordination Polymer-Influence of the Lanthanide on the Nature of the Heteroleptic Anilate/Terephtalate 3D Network
Metal-organic frameworks (MOFs), whose definition has been regularly debated, are a sub-class of coordination polymers (CPs) which may feature both an overall 3D architecture and some degree of porosity. In this context, MOFs based on lanthanides (Ln-MOFs) could find many applications due to the combination of sorption properties and magnetic/luminescent behaviors. Here we report rare examples of 3D Ln-CPs based on anilate linkers, obtained under solvothermal conditions using a heteroleptic strategy. The three compounds of formula [Yb-2(mu-ClCNAn)(2)(mu-F4BDC)(H2O)(4)]center dot(H2O)(3) (1), [Er-2(mu-ClCNAn)(2)(mu-F4BDC)(H2O)(4)]center dot(H2O)(4) (2) and [Eu-2(mu-ClCNAn)(2)(mu-F4BDC)(H2O)(6)] (3) have been characterized by single-crystal X-ray diffraction, thermogravimetric analysis, and optical measurements. Structural characterization revealed that compounds 1 and 2 present an interesting MOF architecture with extended rectangular cavities which are only filled with water molecules. On the other hand, compound 3 shows a much more complex topology with no apparent cavities. We discuss here the origins of such differences and highlight the crucial role of the Ln(III) ion nature for the topology of the CP. Compounds 1 and 2 now offer a playground to investigate the possible synergy between gas/solvent sorption and magnetic/luminescent properties of Ln-MOFs
Repeated Sprint Ability in Young Basketball Players (Part 2): The Chronic Effects of Multidirection and of One Change of Direction Are Comparable in Terms of Physiological and Performance Responses
The aim of this study was to examine the effects of a 5-week training program, consisting of repeated 30-m sprints, on two repeated sprint ability (RSA) test formats: one with one change of direction (RSA) and the other with multiple changes of direction (RSM). Thirty-six young male and female basketball players (age 16.1 ± 0.9 years), divided into two experimental groups, were tested for RSA, RSM, squat jump, counter-movement jump, and the Yo-Yo Intermittent Recovery-Level-1 (Yo-Yo IR1) test, before and after a 4-week training program and 1 week of tapering. One group performed 30-m sprints with one change of direction (RSA group, RSAG), whereas the other group performed multidirectional 30-m sprints (RSM group, RSMG). Both groups improved in all scores in the post-intervention measurements (P < 0.05), except for the fatigue index in the RSM test. However, when comparing the two groups, similar effects were found for almost all parameters of the tests applied, except for RPE in the RSA test, which had a greater decrease in the RSAG (from 8.7 to 5.9) than in the RSMG (from 8.5 to 6.6, P = 0.021). We can conclude that repeated 30-m sprints, either with one change of direction or multidirectional, induce similar physiological and performance responses in young basketball players, but have a different psycho-physiological impact
Repeated Sprint Ability in Young Basketball Players: Multi-direction vs. One-Change of Direction (Part 1)
The aim of the present study was to examine the reliability of a novel multi-direction repeated sprint ability (RSA) test [RSM; 10
7 (6
7 5-m)] compared with a RSA with one change of direction [10
7 (2
7 15-m)], and the relationship of the RSM and RSA with Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1) and jump performances [squat jump (SJ) and counter-movement-jump (CMJ)]. Thirty-six (male, n = 14, female n = 22) young basketball players (age 16.0 \ub1 0.9 yrs) performed the RSM, RSA, Yo-Yo IR1, SJ, and CMJ, and were re-tested only for RSM and RSA after 1 week. The absolute error of reliability (standard error of the measurement) was lower than 0.212 and 0.617-s for the time variables of the RSA and RSM test, respectively. Performance in the RSA and RSM test significantly correlated with CMJ and SJ. The best time, worst time, and total time of the RSA and RSM test were negatively correlated with Yo-Yo IR1 distance. Based on these findings, consistent with previously published studies, it was concluded that the novel RSM test was valid and reliable
Repeated Sprint Ability in Young Basketball Players (Part 2): The Chronic Effects of Multidirection and of One Change of Direction Are Comparable in Terms of Physiological and Performance Responses
The aim of this study was to examine the effects of a 5-week training program, consisting of repeated 30-m sprints, on two repeated sprint ability (RSA) test formats: one with one change of direction (RSA) and the other with multiple changes of direction (RSM). Thirty-six young male and female basketball players (age 16.1 \ub1 0.9 years), divided into two experimental groups, were tested for RSA, RSM, squat jump, counter-movement jump, and the Yo-Yo Intermittent Recovery-Level-1 (Yo-Yo IR1) test, before and after a 4-week training program and 1 week of tapering. One group performed 30-m sprints with one change of direction (RSA group, RSAG), whereas the other group performed multidirectional 30-m sprints (RSM group, RSMG). Both groups improved in all scores in the post-intervention measurements (P < 0.05), except for the fatigue index in the RSM test. However, when comparing the two groups, similar effects were found for almost all parameters of the tests applied, except for RPE in the RSA test, which had a greater decrease in the RSAG (from 8.7 to 5.9) than in the RSMG (from 8.5 to 6.6, P = 0.021). We can conclude that repeated 30-m sprints, either with one change of direction or multidirectional, induce similar physiological and performance responses in young basketball players, but have a different psycho-physiological impact
Simulación del comportamiento dinámico de la turbina de vapor de la CNAI ante un transitorio de rechazo de carga.
Uno de los transitorios más caracterÃsticos de la CNAI es el denominado rechazo
de carga. Se entiende por rechazo de carga la desconección del turbogrupo de la red
eléctrica. El controlador electrohidráulico de las válvulas de admisión de vapor a la
turbina de alta presión debe actuar rápidamente de forma tal que la potencia entregada
por el vapor en su expansión a través de la turbina sea la necesaria para el consumo
interno de la Central. El desbalance existente entre la potencia generada y la requerida,
causa que la turbina se acelere. La velocidad de giro del turbo grupo debe mantenerse
dentro de ciertos lÃmites, en caso contrario se producirá SCRAM del reactor o TRIP de
turbina. Es entonces evidente la importancia de contar con un simulador que permita
preveer el comportamiento del turbo grupo en situaciones no estacionarias desde el
punto de vista tanto de seguridad como de operabilidad de la CentraL
En este trabajo se presenta un simulador del turbo grupo de la CNAI. Para realizar
el simulador se modelaron el regulador electro hidráulico de las válvulas de admisión de
vapor a turbina y la parte térmica de turbina. La realimentación de la turbina con el
controlador permitió obtener el modelo global del conjunto. El simulador fue
programado tanto en entorno WINDOWS como en SIMULINK-MATLAB ®.
El modelo de la parte 'térmica' de la turbina puede además ser utilizado para
realimentar el controlador electrohidráulico real durante las paradas programadas de la
Central debido a que el código corre en tiempo real. Para probar esta parte del trabajo se
realizaron ensayos con tarjetas de adquisición de datos disponibles en el laboratorio de la
División Control del CAB.
La comparación de respuestas obtenidas usando el simulador con mediciones
realizadas en rechazos de carga experimentales mostró buenos resultados
Il paradosso Italia. Tempi e forme di partecipazione femminile al lavoro, strategie di permanenza
Heparin infusion and haemorrhagic complications in patients treated with modified Blalock-Taussig shunt: significance of a nurse and medical audit
The modified Blalock-Taussig shunt is a surgical option in cyanotic patients. In our Institute heparin infusion therapy in the early postoperative period is used to reduce the risk of shunt thrombosis. This may produce haemorrhagic complications. Herein we describe the effect of a multidisciplinary audit to reduce the risk of haemorrhagic complications. Between January 2005 and December 2009, 49 patients received a modified Blalock-Taussig shunt and anticoagulation therapy until the second administration of an antiplatelet drug. Four patients (8.1%) experienced a haemorrhagic event. A multidisciplinary audit was organized to analyze our anticoagulation protocol. The cohort of patients was divided into group 1 and 2: patients without and with haemorrhagic events respectively. Group 2 was characterized by a low level of anticoagulation in the first postoperative day and received a dose of antithrombin III and an increase in heparin infusion. The result was excessive anticoagulation, evidenced by a significant increase in the aPTT from 44 to 138 sec (in Group 1: from 88 to 54 sec). Retrospectively the nursing staff found that these patients presented clinical signs heralding more significant bleeding. The clinical audit depicted a difference between the two groups. Group 2 was initially characterized by heparin resistance and was consequently treated. The nursing staff found that retrospectively there were clinical signs heralding bleeding and created a risk score. Finally the analysis of this data produced a change in the institutional anticoagulation protocol and created a medical and nursing combined protocol for postoperative anticoagulation screening. Since then, the haemorrhagic complications have been reduced significantly