Electrochemical Activation of Ni Catalysts with Potassium Ionic Conductors for CO2 Hydrogenation

Three different kind of Ni-based catalysts were prepared on a K-β″Al2O3 solid electrolyte by combining the annealing of an organometallic paste and the addition of a catalyst powder. The different catalysts films were tested in the CO2 hydrogenation reaction under electrochemical promotion by K+ ions, and were characterized by XRD and SEM. The catalyst film derived from the addition of an α-Al2O3 powder to the Ni catalyst ink presented the highest catalytic activity as a result of the increase in Ni catalyst film porosity. The influence of the applied potential and other operation variables were evaluated on the Ni catalytic activity and selectivity. Hence, the CO production rate was enhanced either by decreasing the applied potential (with the consequent supply of K+ ions to the catalyst surface) or by increasing the CO2 (electron acceptor) feed concentration. On the other hand, CH4 production rate was favoured at positive potentials (removing K+ from the catalyst surface) or by increasing the H2 (electron donor) feed concentration. The global CO2 consumption rate increased upon negative polarization in all experiments and the electrochemical promotion of catalysis effect showed to be reversible and reproducible. Hence, the electrochemical promotion phenomena demonstrated to be a very useful technique to in situ modify and control the catalytic activity and selectivity of a non-noble metal such as Ni for the production of CH4 or syngas via CO2 valorization.Es la versión preprint del artículo. Se puede consultar la versión final en https://doi.org/10.1007/s11244-015-0488-

Spatial localization and pattern formation in discrete optomechanical cavities and arrays

We investigate theoretically the generation of nonlinear dissipative structures in optomechanical (OM) systems containing discrete arrays of mechanical resonators. We consider both hybrid models in which the optical system is a continuous multimode field, as it would happen in an OM cavity containing an array of micro-mirrors, and also fully discrete models in which each mechanical resonator interacts with a single optical mode, making contact with Ludwig and Marquardt (2013 Phys. Rev. Lett. 101, 073603). Also, we study the connections between both types of models and continuous OM models. While all three types of models merge naturally in the limit of a large number of densely distributed mechanical resonators, we show that the spatial localization and the pattern formation found in continuous OM models can still be observed for a small number of mechanical elements, even in the presence of finite-size effects, which we discuss. This opens new venues for experimental approaches to the subject

Efficient microwave-assisted production of furfural from C5 sugars in aqueous media catalysed by Bro¨nsted acidic ionic liquids

Small amounts of SO3H-functionalised room temperature synthesized ionic liquids efficiently dehydrate aqueous xylose to furfural under microwave heating at mild reaction conditions. The RT-ionic liquid catalysts were also found to be effective catalysts for the two step one-pot simultaneous hydrolysis and dehydration of a lignocellulosic waste biorefinery-derived syrup enriched in C5 sugar oligomer

Structure des grands bassins glaciaires dans le nord de la péninsule ibérique: comparaison entre les vallées d'Andorre (Pyrénées orientales), du Gállego (Pyrénées centrales) et du Trueba (Chaîne Cantabrique).

Les grandes vallées glaciaires de la Péninsule Ibérique sont situées dans la chaîne pyrénéo-cantabrique, principalement dans le bassin de l'Èbre. Ainsi, les vallées d'Andorre, de la Noguera Pallaresa et de la haute vallée du Gállego, dans les Pyrénées, ont eu des appareils glaciaires longs de 42, 50 et 40 km respectivement. Dans les vallées du Sil (bassin du Miño) et du Trueba, dans la Chaîne Cantabrique, ils atteignaient 42 et 16,5 km (Serrano-Cañadas, 1996 ; Gómez-Ortiz et al., 2001 ; Turu & Peña, 2006a et b ; Redondo-Vega et al., 2006). L'une des caractéristiques géomorphologiques de la plupart de ces vallées est l'existence d'une dépression morphologique du substratum dans les parties moyennes et terminales, interprétée comme la conséquence de l'érosion glaciaire. Dans tous les cas, on observe une architecture litho-stratigraphique commune (Vilaplana & Casas, 1983 ; Bordonau et al., 1989 ; Bordonau, 1992 ; Turu et al., 2002) représentée par trois unités géoélectriques : une unité inférieure très épaisse, avec des résistivités électriques basses (70 - 200 Ohms par mètre), qui traduit la présence de matériaux fins considérés comme d'origine lacustre ; une unité intermédiaire, moins épaisse, avec des valeurs de résistivité plus élevées (400 - 800 Ohms par mètre), pouvant être interprétée comme un système fluvio-deltaïque pro-glaciaire et une unité géoélectrique supérieure, avec des valeurs de résistivité très variables (100 - 1500 Ohms par mètre), constituée de sédiments alluviaux subactuels. La comparaison des données de type géophysique et géomécanique (sismique à réfraction et essais pressiométriques) montre que l'unité intermédiaire, considérée comme d'origine fluvio-deltaïque, présente des valeurs de vitesse sismique anormalement élevées, ainsi que de hautes valeurs de consolidation. Cette observation effectuée pour la première fois dans la vallée d'Andorre (Turu, 2000) montre des remarquables corrélations entre les hautes vitesses sismiques et les valeurs élevées de consolidation, ainsi que la très nette corrélation entre les hautes valeurs de consolidation et les tills sous-glaciaires. Elle permet d'interpréter l'unité intermédiaire comme essentiellement glaciaire et de remettre en question le modèle simple d'une séquence de comblement lacustre et deltaïque proposé jusqu´à maintenant

Glaciolacustrine deposits formed in an ice-dammed tributary valley in the south-central Pyrenees: new evidence for late Pleistocene climate

Combined geomorphic features, stratigraphic characteristics and sedimentologic interpretation, coupled with optically stimulated luminescence (OSL) dates, of a glacio-fluvio-lacustrine sequence (Linás de Broto, northern Spain) provide new information to understand the palaeoenvironmental significance of dynamics of glacier systems in the south-central Pyrenees during the Last Glacial Cycle (≈130 ka to 14 ka). The Linás de Broto depositional system consisted of a proglacial lake fed primarily by meltwater streams emanating from the small Sorrosal glacier and dammed by a lateral moraine of the Ara trunk glacier. The resulting glacio-fluvio-lacustrine sequence, around 55 m thick, is divided into five lithological units consisting of braided fluvial (gravel deposits), lake margin (gravel and sand deltaic deposits) and distal lake (silt and clay laminites) facies associations. Evolution of the depositional environment reflects three phases of progradation of a high-energy braided fluvial system separated by two phases of rapid expansion of the lake. Fluvial progradation occurred during short periods of ice melting. Lake expansion concurred with ice-dam growth of the trunk glacier. The first lake expansion occurred over a time range between 55 ± 9 ka and 49 ± 11 ka, and is consistent with the age of the Viu lateral moraine (49 ± 8 ka), which marks the maximum areal extent of the Ara glacier during the Last Glacial Cycle. These dates confirm that the maximum areal extent of the glacier occurred during Marine Isotope Stages 4 and 3 in the south-central Pyrenees, thus before the Last Glacial Maximum. The evolution of the Linás de Broto depositional system during this maximum glacier extent was modulated by climate oscillations in the northern Iberian Peninsula, probably related to latitudinal shifts of the atmospheric circulation in the southern North-Atlantic Ocean, and variations in summer insolation intensity

Sialic Acid Glycobiology Unveils Trypanosoma cruzi Trypomastigote Membrane Physiology.

Trypanosoma cruzi, the flagellate protozoan agent of Chagas disease or American trypanosomiasis, is unable to synthesize sialic acids de novo. Mucins and trans-sialidase (TS) are substrate and enzyme, respectively, of the glycobiological system that scavenges sialic acid from the host in a crucial interplay for T. cruzi life cycle. The acquisition of the sialyl residue allows the parasite to avoid lysis by serum factors and to interact with the host cell. A major drawback to studying the sialylation kinetics and turnover of the trypomastigote glycoconjugates is the difficulty to identify and follow the recently acquired sialyl residues. To tackle this issue, we followed an unnatural sugar approach as bioorthogonal chemical reporters, where the use of azidosialyl residues allowed identifying the acquired sugar. Advanced microscopy techniques, together with biochemical methods, were used to study the trypomastigote membrane from its glycobiological perspective. Main sialyl acceptors were identified as mucins by biochemical procedures and protein markers. Together with determining their shedding and turnover rates, we also report that several membrane proteins, including TS and its substrates, both glycosylphosphatidylinositol-anchored proteins, are separately distributed on parasite surface and contained in different and highly stable membrane microdomains. Notably, labeling for α(1,3)Galactosyl residues only partially colocalize with sialylated mucins, indicating that two species of glycosylated mucins do exist, which are segregated at the parasite surface. Moreover, sialylated mucins were included in lipid-raft-domains, whereas TS molecules are not. The location of the surface-anchored TS resulted too far off as to be capable to sialylate mucins, a role played by the shed TS instead. Phosphatidylinositol-phospholipase-C activity is actually not present in trypomastigotes. Therefore, shedding of TS occurs via microvesicles instead of as a fully soluble form

Temas Socio-Jurídicos. Volumen 23 No. 49 Diciembre 2005

El texto que se ofrece a continuación se ha estructurado en función del estudio de dos momentos claves en la configuración del institucionalismo. En un primer momento se retoman las iniciales ideas de Veblen, Commons y Mitchell, buscando identificar en ellas el tópico que las conecta con el proceso de construcción de este marco analítico. En un segundo momento, se examina cómo la ideas de los protoinstitucionalistas mencionados, son retomadas por Coase, Williamson y North en tiempos y contextos relativamente lejanos a los que se plantearon los primeros enfoques, dándole forma a un enfoque analítico concebido para afianzar el rol de las organizaciones y promover la eficiencia en las transacciones sobre las que descansan el bienestar social, la transparencia política y el desarrollo económico.The text offered below has been structured based on the study of two key moments in the configuration of institutionalism. At first, the initial ideas of Veblen, Commons and Mitchell are taken up, seeking to identify in them the topic that connects them with the construction process of this analytical framework. In a second moment, it is examined how the ideas of the aforementioned proto-institutionalists are taken up by Coase, Williamson and North in times and contexts relatively distant from those of the first approaches, giving shape to an analytical approach designed to strengthen the role of organizations and promote efficiency in the transactions on which social welfare, political transparency rest and economic development

Prevalence of high-risk HPV genotypes, categorised by their quadrivalent and nine-valent HPV vaccination coverage, and the genotype association with high-grade lesions

BACKGROUND: The new nine-valent vaccine against human papillomavirus (HPV) includes the four HPV genotypes (6, 11, 16, and 18) that are targeted by the older quadrivalent HPV vaccine, plus five additional oncogenic types (31, 33, 45, 52, and 58) remain significantly associated with high grade lesions. We aimed to determine the prevalence of high-risk HPV genotypes in unvaccinated subjects and the association of these genotypes with the incidence of high-grade lesions. We also assessed which, if either, of these two HPV vaccines could have prevented these cases. METHODS: This cross-sectional study, conducted from 4 January 2010 to 30 December 2011, was composed of 595 women attending the Hospital General Universitario de Elche (Spain) gynaecology department who were positively screened for opportunistic cervical cancer by pap smears and HPV detection during a routine gynaecological health check. The pap smear results were classified using the Bethesda system. HPV genotyping was performed with the Linear Array HPV genotyping test, and viruses were classified by the International Agency for Research on Cancer assessment of HPV carcinogenicity. Odds ratios (ORs) with their 95% confidence intervals (95% CI) were estimated by logistic regression, adjusting for age and immigrant status. The prevented fraction among those exposed (PFe-adjusted) was determined as a measure of impact. RESULTS: At least one of the additional five high-risk HPV genotypes present in the nine-valent HPV vaccine was detected in 20.5% of subjects. After excluding women with genotype 16 and/or 18 co-infection, high-risk genotypes (31, 33, 45, 52, and 58) were associated with a higher risk of intraepithelial lesion or malignancy: adjusted OR?=?3.51 (95% CI, 1.29-9.56), PFe-adjusted?=?0.72 (95% CI, 0.22-0.90). Genotypes that are still non-vaccine-targeted were detected in 17.98% of the women, but these were not significantly associated with high-grade lesions. CONCLUSION: The greater protection of the nine-valent HPV vaccine is likely to have a positive impact because, in the absence of genotype 16 or 18 infection, these five genotypes on their own remained significantly associated with high-grade lesions