Search results for "FOT"
showing 10 items of 1161 documents
Chiral Inversion of 1-Hydroxyethylpyrene Enantiomers Mediated by Enantioselective Sulfotransferases
1998
The benzylic alcohol 1-hydroxyethylpyrene (1-HEP) is activated to a mutagen by sulfotransferases. The sulfuric acid ester formed is difficult to detect, as it is rapidly hydrolysed back to the alcohol. Incubation of the individual enantiomers of 1-HEP with human hydroxysteroid sulfotransferase (hHST) or estrogen sulfotransferase (hEST), expressed in bacteria, led to the formation of the other enantiomer. The rates of sulfation were determined from the initial rates of chiral inversion of the alcohol, knowing that hydrolysis follows an SN1 mechanism and therefore produces racemic alcohol. hEST showed high enantioselectivity for S-1-HEP, whereas hHST strongly preferred the R-enantiomer. The r…
Efecto de la masoterapia sobre la ictericia neonatal: revisión sistemática
2019
espanolObjetivo: Identificar, evaluar y sintetizar la mayor evidencia disponible sobre el efecto del masaje en la ictericia en neonatos a termino tratados o no con fototerapia. Metodo: Se desarrollo una revision siguiendo la declaracion PRISMA. Para ello se realizouna exhaustiva busqueda sistematica en las bases de datos PubMed, Cuiden, Scopus, Scielo y Cnki de los articulos publicados entre enero del 2009 y junio del 2018. Los estudios seleccionados fueron sometidos a una evaluacion de la calidad metodologica mediante la escala PEDro. Resultados: Un total de 10 trabajos cumplian los criterios inclusion y fueron incorporados a la revision. Estos presentaban una calidad metodologica moderada…
Intrinsic Organic Semiconductors as Hole Transport Layers in p–i–n Perovskite Solar Cells
2021
Thin polymeric and small-molecular-weight organic semiconductors are widely employed as hole transport layers (HTLs) in perovskite solar cells. To ensure ohmic contact with the electrodes, the use of doping or additional high work function (WF) interlayer is common. In some cases, however, intrinsic organic semiconductors can be used without any additive or buffer layers, although their thickness must be tuned to ensure selective and ohmic hole transport. Herein, the characteristics of thin HTLs in vacuum-deposited perovskite solar cells are studied, and it is found that only very thin (<5 nm) HTLs readily result inhigh-performing devices, as the HTL acts as a WF enhancer while still ens…
Density of states within the bandgap of perovskite thin films studied using the moving grating technique
2022
In this work, we further study the moving grating technique applied to halide perovskite thin-film materials. First, we show some problems that emerge when analyzing the experimental data with the classical formulation, which does not distinguish between free and trapped carriers and hence only gives average quantities for the transport parameters. We show that using a more general framework, taking into account the multiple trapping of carriers within a density of localized states, allows for an accurate description. Since it includes the density of states (DOS) of the material, it enables the possibility to test different DOS models proposed in the past for halide perovskite thin films. …
CulturePop: un'opera contemporanea tra fotografia e fumetto
2011
Le mucche non sorridono
2019
Cani e gatti (per lo più cuccioli), ma anche elefanti, giraffe, orsi, e naturalmente leoni nell’atto di azzannare gazzelle, aquile con gli artigli protesi, gigantesche balene che danzano nel blu. Il vasto mondo degli animali esiste per la maggior parte di noi sotto forma di fotografia. Alcune di queste immagini, quelle prodotte dai professionisti, spesso sono spettacolari, piene di colori, dettagliate all’inverosimile, e si propongono come una finestra aperta su mondi che difficilmente riusciremo a vedere. In breve la proverbiale massa eteroclita di oggetti e problemi di saussuriana memoria è servita, e al semiologo non resta che trovare un modo per districarsi al suo interno, per capire no…
LOMO sapiens: de la photographie
2015
Une des questions les plus fréquentes, dans les recherches sur la photographie, est liée à la valeur de médiation de l’image et donc au rapport qu’elle entretient avec la soi-disant réalité. D’un côté, la certitude de la présence devant l’objectif de ce que nous voyons représenté, une copie du monde excluant la nécessité d’un code pour être comprise, de l’autre, l’imposition d’un point de vue situé dans le temps et l’espace qui, par ces choix obligés, porte en soi le germe d’une stratégie de la communication. La sémiotique devient ainsi l’instrument pour analyser ces stratégies, pour rechercher des signifiés plus ou moins cachés, en démontant l’évidence supposée de l’image photographique. D…