Search results for "porte"
showing 10 items of 1894 documents
Perceived barriers to active commuting to school: reliability and validity of a scale
2016
Resumen Objetivo: Examinar la fiabilidad y la validez de una escala para evaluar las barreras percibidas en el desplazamiento activo al centro escolar en jóvenes españoles. Método: La validez de la escala fue evaluada en una muestra de 465 adolescentes (14-18 años de edad) mediante un análisis factorial confirmatorio y a través de la asociación con el transporte activo autorreportado. Una submuestra completó la escala dos veces, con una separación de una semana, a fin de evaluar su fiabilidad. Resultados: Los resultados mostraron que la escala tenía índices de ajuste satisfactorios con dos factores. Un factor incluyó los ítems relativos a ambiente y seguridad (α = 0,72), y otro los ítems so…
Barreras percibidas en el desplazamiento activo al centro educativo: fiabilidad y validez de una escala
2016
Resumen: Objetivo: Examinar la fiabilidad y la validez de una escala para evaluar las barreras percibidas en el desplazamiento activo al centro escolar en jóvenes españoles. Método: La validez de la escala fue evaluada en una muestra de 465 adolescentes (14-18 años de edad) mediante un análisis factorial confirmatorio y a través de la asociación con el transporte activo autorreportado. Una submuestra completó la escala dos veces, con una separación de una semana, a fin de evaluar su fiabilidad. Resultados: Los resultados mostraron que la escala tenía índices de ajuste satisfactorios con dos factores. Un factor incluyó los ítems relativos a ambiente y seguridad (α = 0,72), y otro los ítems s…
Activation of classical protein kinase C decreases transport via systems y+and y+L
2007
Activation of protein kinase C (PKC) downregulates the human cationic amino acid transporters hCAT-1 (SLC7A1) and hCAT-3 (SLC7A3) (Rotmann A, Strand D, Martiné U, Closs EI. J Biol Chem 279: 54185–54192, 2004; Rotmann A, Vekony N, Gassner D, Niegisch G, Strand D, Martine U, Closs EI. Biochem J 395: 117–123, 2006). However, others found that PKC increased arginine transport in various mammalian cell types, suggesting that the expression of different arginine transporters might be responsible for the opposite PKC effects. We thus investigated the consequence of PKC activation by phorbol-12-myristate-13-acetate (PMA) in various human cell lines expressing leucine-insensitive system y+[hCAT-1, h…
Cationic amino acid transport across the blood-brain barrier is mediated exclusively by system y+.
2006
Cationic amino acid (CAA) transport is brought about by two families of proteins that are found in various tissues: Cat (CAA transporter), referred to as system y+, and Bat [broad-scope amino acid (AA) transporter], which comprises systems b0,+, B0,+, and y+L. CAA traverse the blood-brain barrier (BBB), but experiments done in vivo have only been able to examine the BBB from the luminal (blood-facing) side. In the present study, plasma membranes isolated from bovine brain microvessels were used to identify and characterize the CAA transporter(s) on both sides of the BBB. From these studies, it was concluded that system y+was the only transporter present, with a prevalence of activity on the…
Transport of C(4)-dicarboxylates in Wolinella succinogenes.
2000
ABSTRACT C 4 -dicarboxylate transport is a prerequisite for anaerobic respiration with fumarate in Wolinella succinogenes , since the substrate site of fumarate reductase is oriented towards the cytoplasmic side of the membrane. W. succinogenes was found to transport C 4 -dicarboxylates (fumarate, succinate, malate, and aspartate) across the cytoplasmic membrane by antiport and uniport mechanisms. The electrogenic uniport resulted in dicarboxylate accumulation driven by anaerobic respiration. The molar ratio of internal to external dicarboxylate concentration was up to 10 3 . The dicarboxylate antiport was either electrogenic or electroneutral. The electroneutral antiport required the prese…
Immuno-SLM—a combined sample handling and analytical technique
2004
Immuno-supported liquid membrane (immuno-SLM) extraction is a new technique that makes use of antibody (Ab)-antigen interactions as the "extraction force" to drive the mass transfer in a selective way. In immuno-SLM, anti-analyte (Ag) Abs are introduced into the acceptor phase of the SLM unit to trap the Ag that passes from the flowing donor through the SLM into the stagnant acceptor. The amount of immuno-extracted analyte (AbAg) is quantified by connecting the immuno-SLM unit on-line with a non-competitive heterogeneous fluorescence flow immunoassay (FFIA) that makes use of a fluorescein-labeled analyte tracer that titrates the residual excess of Ab present in the acceptor. A restricted ac…
Intralaboratory validation of four in vitro assays for the prediction of the skin sensitizing potential of chemicals
2011
Abstract Allergic contact dermatitis is induced by repeated skin contact with an allergen. Assessment of the skin sensitizing potential of chemicals, agrochemicals, and especially cosmetic ingredients is currently performed with the use of animals. Animal welfare and EU legislation demand animal-free alternatives reflected in a testing and marketing ban for cosmetic ingredients beginning in 2013. The underlying mechanisms of induction and elicitation of skin sensitization are complex and a chemical needs to comply several properties being skin sensitizing. To account for the multitude of events in the induction of skin sensitization an in vitro test system will consist of a battery of vario…
Sterically geared tris-thioureas; transmembrane chloride transporters with unusual activity and accessibility
2015
Tris-N-arylthioureas derived in one step from 1,3,5-tris(aminomethyl)-2,4,6-triethylbenzene are remarkably effective anion carriers. With optimised aryl substituents their activities come close to the best currently known, suggesting that they might find use as readily available standards in anion transport research.
Eight-Membered Rings With Two Heteroatoms 1,3
2022
Eight-membered rings with two heteroatoms in a 1,3-relationship, namely 1,3-diazocine, 2H-1,3-oxazocine, 2H-1,3-thiazocine, 4H-1,3-dioxocin, 4H-1,3-oxathiocin, and 4H-1,3-dithiocin, are discussed in this chapter, that covers the literature from 2007 to October 2020 (SciFindern search) and reports the chemistry of uncondensed derivatives, heterocines fused to carbocycles and heterocycles, as well as bridged heterocines. Among eight-membered 1,3-diheterocines, 1,3-diazocines and 1,3-oxazocines are the two largest classes, based on the number of publications, mostly due to the studies of the synthesis of these cyclic systems, their pharmacological properties and/or their important industrial a…
Preíndices que determinan la anticipación del portero de hockey hierba ante un golpeo de revés
2015
La tesis se encuadra en el estudio de los elementos perceptivos y atencionales que modulan la captación de información, aspecto clave para la toma de decisión y posterior acción motriz que conforman el modelo de procesamiento de la información (Marteniuk, 1976). Para la correcta ejecución de muchas de las acciones que se realizan en la actividad deportiva, la capacidad de extraer del entorno la información más relevante y procesarla adecuadamente es esencial. Esta capacidad se torna más relevante aún en los deportes de predominio de situaciones abiertas, como las que caracterizan a los deportes de equipo, donde la dinámica del entorno en el que se desarrollan las acciones genera gran cantid…