Flexibility of the imidazolium based ionic liquids/water system for the synthesis of siliceous 10-ring containing microporous frameworks

By using asymmetric di-substituted imidazolium molecules (1-Butyl-3-methylimidazolium (BMIM) and 1-Ethyl-3-methylimidazolium (EMIM) bromide) as the structure directing agents, in combination with simple changes in silica source or sodium/water content it is possible to prepare three pure phase microporous 10-ring siliceous zeolitic structures. The crystallizations are comparatively rapid with fully crystalline material resulting in 1–3 days at 443 K. In contrast to many recipes reported for pure silica materials, the synthesis is performed without the use of HF or without the need to alter the properties of the SDA, while significantly lower amounts of both ionic liquid and mineralizing agent are required. The results obtained indicate that effective phase control can be achieved from a primary gel composition by minor changes to either the silica source or the water/sodium content, with a strong specificity in the formation of topologies with interconnected 10-rings

Determination of the nature of the Cu coordination complexes formed in the presence of NO and NH3 within SSZ-13

Ammonia-selective catalytic reduction (NH3-SCR) using Cu zeolites is a well-established strategy for the abatement of NOx gases. Recent studies have demonstrated that Cu is particularly active when exchanged into the SSZ-13 zeolite, and its location in either the 6r or 8r renders it an excellent model system for fundamental studies. In this work, we examine the interaction of NH3-SCR relevant gases (NO and NH3) with the Cu2+ centers within the SSZ-13 structure, coupling powder diffraction (PD), X-ray absorption spectroscopy (XAFS), and density functional theory (DFT). This combined approach revealed that, upon calcination, cooling and gas exposure Cu ions tend to locate in the 8r window. After NO introduction, Cu-ions are seen to coordinate to two framework oxygens and one NO molecule, resulting in a bent Cu-nitrosyl complex with a Cu-N-O bond angle of similar to 150 degrees. Whilst Cu seems to be partially reduced/changed in coordination state, NO is partially oxidized. On exposure to NH3 while the PD data suggest the Cu2+ ion occupies a similar position, simulation and XAFS pointed toward the formation of a Jahn-Teller distorted hexaamine complex [Cu(NH3)(6)](2+) in the center of the cha cage. These results have important implications in terms of uptake and storage of these reactive gases and potentially for the mechanisms involved in the NH3-SCR process

Operando Spectroscopic Studies of Cu–SSZ-13 for NH3–SCR deNOx Investigates the Role of NH3 in Observed Cu(II) Reduction at High NO Conversions

The small pore zeolite chabazite (SSZ-13) in the copper exchanged form is a very efficient material for the selective catalytic reduction by ammonia (NH 3 ) of nitrogen oxides (NOx) from the exhaust of lean burn engines, typically diesel powered vehicles. The full mechanism occurring during the NH 3 –SCR process is currently debated with outstanding questions including the nature and role of the catalytically active sites. Time-resolved operando spectroscopic techniques have been used to provide new level of insights in to the mechanism of NH 3 –SCR, to show that the origin of stable Cu(I) species under SCR conditions is potentially caused by an interaction between NH 3 and the Cu cations located in eight ring sites of the bulk of the zeolite and is independent of the NH 3 –SCR of NOx occurring at Cu six ring sites within the zeolite

Cobertura territorial y equidad distribucional en la red de acceso público a la información en la Provincia del Chaco–API

Una red de Acceso Público a la Información (API) compuesta fundamentalmente por Bibliotecas Populares (BP) y Centros Tecnológicos Comunitarios (CTC) se constituye en instrumento de desarrollo al permitir el acceso colectivo a las TICs, dado que la comunidad puede hacer uso de equipamiento informático y de una conexión a Internet sin tener que asumir los costos involucrados en estos procesos. En este aporte se analiza la localización de dichos puntos de acceso en la provincia del Chaco, examinándose tanto la cobertura territorial como la equidad distribucional de los mismos empleando SIG y calculando distintos índices de localización y concentración. Los resultados demuestran una desigual distribución de los recursos apreciándose asimismo desorden territorial en la localización de ellos

Single nucleotide polymorphism (SNP) analysis used for the phylogeny of the Mycobacterium tuberculosis complex based on a pyrosequencing assay

Background Different polymorphisms have been described as markers to classify the lineages of the Mycobacterium tuberculosis complex. The analysis of nine single nucleotide polymorphisms (SNPs) was used to describe seven SNPs cluster groups (SCGs). We attempted to classify those strains that could not been categorized into lineages by the genotyping methods used in the routine testing. Results The M. tuberculosis complex isolates collected in 2010 in our region were analysed. A new method based on multiplex-PCRs and pyrosequencing to analyse these SNPs was designed. For the pyrosequencing assay nine SNPs that defined the seven SCGs were selected from the literature: 1977, 74092, 105139, 232574, 311613, 913274, 2460626, 3352929 and gyrA95. In addition, SNPs in katG463, mgtC182, Ag85C103 and RDRio deletion were detected

Bullous pemphigoid and dipeptidyl peptidase-4 inhibitors: The importance of the pharmacotherapeutic history

A 97-year-old man with a history of type II diabetes mellitus was treated with oral antidiabetic agents. He went to the emergency department after the appearance of blister-like itchy lesions on the abdomen and extremities since 2 months. The examination revealed eczematous lesions on the back, abdomen and extremities along with tense blisters on an erythematous base and serous content (figure 1A). In the blood test carried out, 285?mg/dL glucose and 7.1% eosinophilia stood out, with no associated leucocytosis or other relevant findings. Positive glycosuria (+++) was observed in urinalysis without other alterations. A skin biopsy was performed for histological and immunofluorescence studies that confirmed the diagnosis of bullous pemphigoid (figure 1B–D). Given the poor control of autoimmune blistering disease, possible triggers were looked for and linagliptin intake could be associated with the appearance of skin lesions 1?month earlier. ..

Visualising Co nanoparticle aggregation and encapsulation in Co/TiO2 catalysts and its mitigation through surfactant residues

Due to the reducible nature of TiO2, the encapsulation of cobalt nanoparticles (CoNPs) by reduced TiO2-x is often reported to decrease their catalytic performance in reactions such as Fisher-Tropsch synthesis (FTS). Here, we show using HAADF-STEM imaging and electron energy loss spectroscopy (EELS) that a residual C12E4 surfactant used to prepare the CoNPs, remains on the surface of a TiO2 rutile support, preventing the formation of Ti3+/Ti2+ oxides and therefore TiO2-x migration. Furthermore, the presence of these surfactant residues prevents the coalescence and aggregation of CoNPs during catalyst preparation, maintaining the dispersion of CoNPs. As such, using C12E4 in the preparation of Co/TiO2 can be considered beneficial for producing a catalyst with a greater number of active Co species

Mesozooplankton size structure in the Canary Current System

Changes in plankton composition influences the dynamics of marine food webs and carbon sinking rates. Understanding the core structure and function of the plankton distribution is of paramount importance to know their role in trophic transfer and efficiency. Here, we studied the zooplankton distribution, abundance, composition, and size spectra for the characterization of the community under different oceanographic conditions in the Canaries-African Transition Zone (C-ATZ). This region is a transition zone between the coastal upwelling and the open ocean showing a high variability because of the physical, chemical, and biological changes between eutrophic and oligotrophic conditions through the annual cycle. During the late winter bloom (LWB), chlorophyll a and primary production were higher compared to that of the stratified season (SS), especially in the upwelling influenced area. Abundance distribution analysis clustered stations into two main groups according to the season (productive versus stratified season), and one group sampled in the upwelling influenced area. Size-spectra analysis showed steeper slopes during daytime in the SS, suggesting a less structured community and a higher trophic efficiency during the LWB due to the favorable oceanographic conditions. We also observed a significant difference between day and nighttime size spectra due to community change during diel vertical migration. Cladocera were the key taxa differentiating an Upwelling-group, from a LWB- and SS-group. These two latter groups were differentiated by Salpidae and Appendicularia mainly. Data obtained in this study suggested that abundance composition might be useful when describing community taxonomic changes, while size-spectra gives an idea of the ecosystem structure, predatory interactions with higher trophic levels and shifts in size structure

INCIDENCIA DEL RENDIMIENTO ACADÉMICO EN LA DURACIÓN DE LA CARRERA DE EGRESADOS DE LA FOLP

El rendimiento académico es uno de los indicadores de gestión de las instituciones educativas que no solo pone en evidencia las capacidades de los educandos, sino también los factores que las afectan. El objetivo de este estudio es analizar la incidencia del rendimiento académico en la duración de la carrera de los egresados de la FOLP. Se realizó una investigación de tipo cuantitativo, descriptivo, longitudinal y correlacional en la que se examinó, desde la duración real de la carrera, el rendimiento académico de los alumnos graduados entre el 1-1-1984 y el 31-12-2004. La información se recolectó a través del Programa de Evaluación y Seguimiento de los Egresados de la FOLP. La exploración tuvo carácter inductivo. Se trabajó con la población total n = 5628, de la que se tomaron como referentes los egresados a término (5años) y aquellos que permanecieron el doble del tiempo estipulado curricularmente (10 años). Se construyeron tablas de distribución de frecuencias. Las variables correlacionadas fueron duración de la carrera y rendimiento académico y los indicadores utilizados: coeficiente de rendimiento académico (CRA); media (x); mediana (M); máximos (Mx); mínimos (Mn); promedio (Pr) y aplazos (A). Se confeccionaron gráficos de dispersión. La correlación entre variables se calculó usando la fórmula r de Pearson y para establecer su influencia se aplicó el coeficiente de determinación R2. Se utilizó el programa estadístico SPSS 10.0. Las variables se procesaron en forma numérica, obteniéndose los siguientes resultados: I) Duración 5 años = 22,67% de la población total; xPr = 6,74; MPr = 6,78; MxPr = 9,36; MnPr = 4,88; xCRA = 61,62; MCRA = 63,81; MxCRA = 99,36; MnCRA = 23,41; el 40,2% egresó S/A. II) Duración 10 años = 3,42% de la población total; xPr = 6,74; MPr = 4,95; MxPr = 7,6; MnPr = 3,36; xCRA = 25,84; MCRA = 27,37; MxCRA = 45,6; MnCRA = 9,06; el 1,03% egresó S/A. La correlación fue r = - 0,62 y el computo de variable arrojó un R2 = 39% para la influencia del rendimiento académico en la duración de la carrera. De lo expuesto se puede concluir que hay una dirección de correlación significativa y con fuerte incidencia del rendimiento académico de los alumnos en la duración de la carrera