Efficiency and reliability enhancement of silicon nanocrystal field-effect luminescence from nitride-oxide gate stacks

We report on a field-effect light emitting device based on silicon nanocrystals in silicon oxide deposited by plasma-enhanced chemical vapor deposition. The device shows high power efficiency and long lifetime. The power efficiency is enhanced up to 0.1 %25 by the presence of a silicon nitride control layer. The leakage current reduction induced by this nitride buffer effectively increases the power efficiency two orders of magnitude with regard to similarly processed devices with solely oxide. In addition, the nitride cools down the electrons that reach the polycrystalline silicon gate lowering the formation of defects, which significantly reduces the device degradation.

The Transnational Zombie: Postcolonial Memory and Rage in the Recent European Horror Film

An ever increasing number of films, books, and scholarly works dealing with the undead have appeared in the last decade, making the zombie the very incarnation of American popular culture on a global scale. In this chapter I show that the zombie is also a surprisingly complex sign for transnational movement and multidirectional cultural flow. While the zombie may appear as the very epitome of American cultural production and influence, a mindless movie monster born of a vapid stream of Hollywood B-horror, the zombie has a rich transnational history and an eloquent figurative resonance that have fed into its current ubiquity as cultural sign. This chapter reviews that history and then examines some of the ways that the zombie figure has traveled between the Caribbean, where it emerged, the United States, where it was translated into a film device of startling pathos and horror, and Europe, to which it owes some of its most interesting recent innovations.

Nitric oxide sustains IL-1β expression in human dendritic cells enhancing their capacity to induce IL-17-producing T-cells.

The role played by lung dendritic cells (DCs) which are influenced by external antigens and by their redox state in controlling inflammation is unclear. We studied the role played by nitric oxide (NO) in DC maturation and function. Human DCs were stimulated with a long-acting NO donor, DPTA NONOate, prior to exposure to lipopolysaccharide (LPS). Dose-and time-dependent experiments were performed with DCs with the aim of measuring the release and gene expression of inflammatory cytokines capable of modifying T-cell differentiation, towardsTh1, Th2 and Th17 cells. NO changed the pattern of cytokine release by LPS-matured DCs, dependent on the concentration of NO, as well as on the timing of its addition to the cells during maturation. Addition of NO before LPS-induced maturation strongly inhibited the release of IL-12, while increasing the expression and release of IL-23, IL-1β and IL-6, which are all involved in Th17 polarization. Indeed, DCs treated with NO efficiently induced the release of IL-17 by T-cells through IL-1β. Our work highlights the important role that NO may play in sustaining inflammation during an infection through the preferential differentiation of the Th17 lineage.

La controverse avant le film : quelle politique pour Good Night, And Good Luck ?

This article aims to explain how newspapers commented on the movie Good Night, and Good Luck before its release. The media coverage anticipated George Clooney's film as a partisan attack launched against George W. Bush's policy since 9/11. Clooney advocates another reading: the historic confrontation between journalist Edward Murrow and Senator Joseph McCarty permits to reflect on the crucial role that the media play for democracy. Such reflection tries to prevent the dividing of the public sphere into antagonistic camps opposing "friends" to "foes," a division that undermines the possibility of a true pluralism. Our socio-semiotic analysis will focus on the critical work accomplished by the media, and on the way that work determines the collective meaning of a cultural object. Simultaneously, we will discuss the necessary conditions for pluralism in a public sphere.

L'origine picturale du cinéma : le tableau vivant, une esthétique du film des premiers temps

Le cinéma des premiers temps, c'est-à-dire la production des deux premières décennies du cinéma, majoritairement caractérisée par des plans autonomes, des histoires courtes et un cadre fixe, n'a essentiellement connu d'études esthétiques que sous un angle narratologique, centrées notamment sur les prémisses du montage. Cette thèse déplace le regard - ou plus simplement le convoque -, en proposant de faire sa place à l'image. Car à qui sait les regarder, les premiers films dévoilent une parenté picturale jusqu'alors ignorée. Les images du cinéma des premiers temps - alors significativement appelées « tableaux » - se sont en effet définies à l'aune de la peinture, et même plus précisément par une imitation littérale des oeuvres d'art. Cette étude révèle que le tableau vivant, défini dans les termes stricts de la reconstitution d'une composition picturale par des acteurs vivants (que ceux-ci tiennent la pose ou non), est au fondement d'une esthétique du film des premiers temps. L'argument est structuré par les illustrations que l'auteure exhume (et compare, à la manière d'un spectaculaire et vivant jeu des 7 différences) parmi cette production filmique majoritairement disparue, brûlée, effacée, et ces références picturales aujourd'hui perdues, dénigrées, oubliées... Néanmoins ce ne sont pas quelques exemples isolés, mais un vrai phénomène historique qui est mis au jours à travers un corpus de films traversant tous les genres du cinéma des premiers temps, et prouvant que les productions du Film d'Art et des séries d'art ou le film Corner in Wheat (D.W. Griffith, 1909), souvent tenus comme un commencement, consistent bien plus en un aboutissement de cette tradition qui consiste à créer des images filmiques sous forme de tableaux vivants. Traçant d'abord ses « contexte et contours », le texte montre que la reconstitution picturale hante toutes les formes de spectacle à l'heure de l'émergence du cinéma. Les scènes de l'époque cultivent internationalement une esthétique de tableau vivant. Et la scène n'a pas l'exclusivité du phénomène : le médium photographique, dès son apparition, s'approprie le procédé, pour (chose jusqu'alors impossible) documenter l'effet visuel de ces reconstitutions, mais aussi pour les réinventer, en particulier pour se légitimer en tant que moyen artistique capable de rivaliser avec la peinture. Le cinéma émergent procède à une appropriation similaire du tableau vivant, qui fait le coeur de ce travail en y étant analysée selon quatre axes théoriques : Reproduire - où l'on découvre le caractère fondamentalement indirect de la filiation picturale de ces tableaux vivants, pris dans une dynamique de reproduction intermédiale qui en fait de véritables exercices de style, par lesquels les producteurs expérimentent et prennent conscience des moyens .artistiques de l'image filmique - ; Réincarner - où l'on étudie les problématiques engagées par la « mise en vie », et plus précisément la « mise en corps » des figures picturales (en particulier de Jésus et du nu), impliquant des enjeux de censure et un questionnement du regard sur l'art, sur le corps, et sur le statut de ces images qui semblent plus originales que l'original - ; Réanimer - où l'on examine la manière dont le cinéma mouvemente la peinture, en remettant la composition en action, en en redéployant l'instant prégnant, en expérimentant la pose gestuelle, l'arrêt du photogramme et tout le spectre de la temporalité cinématographique - ; enfin Recadrer - où l'on analyse le cadrage de ces tableaux repensés à l'aune de la caméra et de l'écran, qui nécessitent de complexifier les catégories théoriques baziniennes, et qui font émerger le tableau vivant comme un lieu de cristallisation d'une image filmique tabu/aire, offrant une résistance au montage linéaire. Or cette résistance se vérifiera jusque dans les films très contemporains, qui, en réactualisant le motif du tableau vivant, briseront la linéarité narrative du montage et feront rejaillir le poids artistique de l'image - ravivant en cela une esthétique fondatrice du cinéma.

Catálise eletroquímica da redução do bromato em superfícies modificadas por filmes de molibdênio

In this paper some studies concerning the electroreduction of Mo(VI) in sulphuric acid solutions are described. We have shown that at suitable experimental conditions very stable molybdenum oxide films can be electrochemically deposited at glassy carbon electrodes, the reduction of bromate occurring at less negative potentials on the modified surface. Coulometric experiments have shown that bromide is not the only product of the catalytic bromate reduction by the molybdenum film and species like BrO2 may have part in this process. Based on chronoamperometric curves recorded at -0.60 V, analytical curves have been obtained for the reduction of bromate in the 0.1 - 0.8 mM range, a limit of detection of 20 µM for bromate being determined.

Caracterização de filmes finos de Nb2O5 com propriedades eletrocrômicas

The sols for thin electrochromic coatings of Nb2O5 were obtained by synthesis of the niobium butoxide from BuONa and NbCl5. The ~300nm thick films were deposited by dip-coating technique from the alkoxide solution and calcined at 560ºC in O2 atmosphere during 3 hours. The particles size of niobium oxide (V) powder (~20mm) was obtained from x-ray diffraction using the Scherrer equation. The coatings were characterized by cyclic voltammetry and cronoamperommetry techniques. The spectral variation of the optical transmittance were determined in situ as a function of the cyclical potencial and memory effect. The insertion process of lithium is reversible and change the film color from transparent (T=80%) to dark blue (T=20%).

Ultralow-density nanocage-based metal-oxide polymorphs

For two important metal oxides (MO, M=Mg, Zn) we predict, via accurate electronic structure calculations, that new low-density nanoporous crystalline phases may be accessible via the coalescence of nanocluster building blocks. Specifically, we consider the assembly of cagelike (MO)12 clusters exhibiting particularly high gas phase stability, leading to new polymorphs with energetic stabilities rivaling (and sometimes higher) than those of known MO polymorphs.

Eletroxidação do etanol em eletrodos de Ti/IrO2

It has been carried out an investigation of ethanol electro-oxidation on Ti/IrO2 electrodes. The experimental results show a high selectivity towards acetaldehyde formation thus, offering potential advantages in cost and availability of raw material. It has been observed that the electrode is partially blocked by a film formed after the oxidation of the starting material which can be removed by pulse technique between RDO and RDH onset. The mechanism and the selectivity of the product formed is presented.