Glycerol transformation on several heterogeneous acid-base and supported metal catalysists under different redox conditions

1. Introducción o motivación de la tesis Durante las últimas décadas, los investigadores han dirigido sus esfuerzos hacia la protección del medio ambiente y al desarrollo de procesos sostenibles con el entorno [1,2]. Uno de los procesos en los que se han producido avances importantes es la síntesis de biocombustibles (biogás, biodiesel,…). En este sentido, el uso de la biomasa como fuente de energía no sólo satisface la necesidad energética sino que también proporciona una serie de compuestos químicos funcionalizados, que pueden ser empleados como punto de partida para multitud de procesos [1,3-6]. Con esta premisa, investigadores del Pacific Northwest National Laboratory (USA) y del National Renewable Energy Laboratory (USA) publicaron un informe en el que se analizaban posibles compuestos de partida (building blocks o platform molecules) para el desarrollo de una química basada en la biomasa, que emplearía estos compuestos fácilmente transformables en otros productos de alto valor añadido [5,6]. El glicerol (1,2,3-propanotriol) ha sido identificado como una de las 12 moléculas de partida derivadas de la biomasa que pueden ser convertidas en productos químicos o materiales de alto valor añadido [1,4- 7]. El glicerol se encuentra en la biomasa utilizada como materia prima para la obtención de biodiesel en forma de ésteres de ácidos grasos o triglicéridos, provenientes principalmente de aceites vegetales [8]. La obtención del biodiesel se realiza vía hidrólisis o metanolisis de los...1. Introduction and motivation of the thesis Over the last few decades, researchers have directed their efforts toward environmental protection and the development of sustainable processes [1,2]. This approach has led to major advances in some processes such as biofuels synthesis (biogas, biodiesel, ...). The use of biomass as an energy source not only supply an energetic demand but also provides a wide range of functionalized chemical compounds that can be used as a starting point for many processes [1,3-6]. Considering all these possibilities, researchers from both the Pacific Northwest National Laboratory (USA) and the National Renewable Energy Laboratory (USA) published a report including the most promising starting compounds (building blocks or platform molecules) for the development of a biomass based chemistry, with biomass as a renewable source of these building blocks that can be easily transformed into other products with high added value [5.6]. Glycerol has been identified as one of the 12 proposed starting molecules derived from biomass that can be converted into other added-value chemicals [1,4-7]. Glycerol can be found in the vegetable oils used as raw material for biodiesel, mainly as fatty acid esters or triglycerides [8]. Biodiesel production is carried out via hydrolysis or methanolysis of triglycerides [9], reaching a ratio of 10 kg of glycerol as by-product per 100 kg of biodiesel in biorefinery. Many different chemical processes have been described for the valorisation of glycerol, such as aqueous phase reforming, polymerization, fermentation,..

CtIP-Specific Roles during Cell Reprogramming Have Long-Term Consequences in the Survival and Fitness of Induced Pluripotent Stem Cells

Acquired genomic instability is one of the major concerns for the clinical use of induced pluripotent stem cells (iPSCs). All reprogramming methods are accompanied by the induction of DNA damage, of which double-strand breaks are the most cytotoxic and mutagenic. Consequently, DNA repair genes seem to be relevant for accurate reprogramming to minimize the impact of such DNA damage. Here, we reveal that reprogramming is associated with high levels of DNA end resection, a critical step in homologous recombination. Moreover, the resection factor CtIP is essential for cell reprogramming and establishment of iPSCs, probably to repair reprogramming-induced DNA damage. Our data reveal a new role for DNA end resection in maintaining genomic stability during cell reprogramming, allowing DNA repair fidelity to be retained in both human and mouse iPSCs. Moreover, we demonstrate that reprogramming in a resection-defective environment has long-term consequences on stem cell self-renewal and differentiation.España, Ministerio de Economía y Competitividad SAF2013-43255-

Genetic variability in two spanish horse populations: preliminary results

The genetic variability has been analyzed through the allelic frequencies distribution of ten STR (Short Tandem Repeat) equine loci of three different horse populations, Asturcón, Pottoka and Thoroughbred (PSI), which is considered as an outgroup. The genetic variability found in the pony breeds is higher than for PSI and only one of the ten loci analyzed is significantly desviated from Hardy-Weinberg equilibrium (= 0.01) in Asturcón and Pottoka populations. The FST value (0.054) shows a significant divergence between Asturcón and Pottoka, besides the genetic distance calculated between both populations is very lower compared to their relation with PSI.Para el estudio de la variabilidad genética de tres poblaciones diferentes de caballos, Asturcón, Pottoka y Pura Sangre Inglés (PSI), habiéndose constituido esta última como población de referencia, se ha analizado la distribución de las frecuencias alélicas de 10 STR (Short Tandem Repeat) loci equinos. La variabilidad genética encontrada en las razas de ponis es superior a la del PSI y solo uno de los loci analizados se desvía significativamente del equilibrio Hardy- Weinberg (=0,01) en las poblaciones de Asturcón y Pottoka. El valor FST estimado (0,054) muestra una divergencia significativa entre Asturcón y Pottoka, asimismo la distancia genética calculada entre ambas poblaciones es inferior comparada a la que tienen ambas con respecto al PSI

Influence of Boron, Tungsten and Molybdenum Modifiers on Zirconia Based Pt Catalyst for Glycerol Valorization

The influence of boron, tungsten and molybdenum modifiers on zirconia-based Pt catalyst was studied for glycerol valorization. Zirconia modified supports were prepared by impregnation of ZrO2 with either boric, silicontungstic or phosphomolybdic acids to obtain supports with enhanced Brönsted acidic properties. The modified supports were subsequently impregnated with chloroplatinic acid to obtain Pt-based catalysts. Pt incorporation resulted in the increase in Lewis acidity of the solids, being more significant for the Pt//W/ZrO2 catalyst. Reduced Pt catalysts were tested for the liquid-phase glycerol hydrogenolysis, observing a synergistic effect between catalyst acid sites and metal function that proved to be crucial in glycerol hydrogenolysis. The Pt//W/ZrO2 catalyst was the most active catalyst in this reaction, being the only leading to 1,3-PDO (45% sel., 160 °C) while Pt//Mo/ZrO2 is the best option for 1,2-PDO (49% sel., 180 °C). Reusability studies carried out for Pt//W/ZrO2 showed that catalytic activity dropped after the first use, remaining constant for the second and subsequent ones. Selectivity to reaction products also changes during reuses. Therefore, the selectivity to 1,2 PDO increases in the first reuse in detriment to the selectivity to n-propanol whereas the selectivity to 1,3-PDO remains constant along the uses. This behavior could be associated to the lixiviation of W species and/or catalyst fouling during reaction runs

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