Synthesis of hydroxyfatty esters by sequential epoxidation-hydrogenolysis: Solvent effects

The tandem/sequential combination of epoxidation and hydrogenolysis for unsaturated fatty esters is not straightforward, due to incompatibility problems with the impurities present or generated in the used solvents. The chlorinated impurities in alpha, alpha, alpha-trifluorotoluene leads to the formation of important amounts of chlorohydrins by HCl formation in the hydrogenolysis step. The use of trifluoroethanol (TFE) in the epoxidation step produces trifluoroacetic acid traces by oxidation, responsible for the opening of the epoxide with water and TFE. The solvent of choice was finally isobutyl acetate, which gathers the required physicochemical properties, with 85 % yield of hydroxystearates from methyl oleate in a sequential process

Simple metal-free oxidative cleavage of 1,2-diols

Cleavage of 1,2-diols is easily carried out under mild conditions with the Oxone/KBr (or Oxone/NaCl) method in either acetonitrile/water or tert-butanol/water medium at room temperature. This procedure is highly efficient for the cleavage of dihydroxyfatty esters and acids. The reaction takes place through a double oxidation of the 1,2-diol, leading to the 1,2-diketone that undergoes a Baeyer-Villiger oxidation, with a final hydrolysis of the generated anhydride. The application to other diols, including simple internal and terminal diols, is also possible, but the nature of the diol substrate conditions the optimal halide/solvent system, given that important differences in reactivity are observed. These differences are ascribed to the change in the rate limiting step depending on the substrate/halide/solvent combinatio

Catalytic hydrolysis of epoxyfatty esters with solid sulfonic acids

Four sulfonic resins are able to promote the hydrolysis of several epoxyfatty esters becoming a very interesting strategy to obtain polyols from epoxyfatty derivatives. The choice of the aqueous solvent and temperature is critical to improve the accessibility of reagents to the acidic catalytic sites. Tert-butanol/water mixture as solvent at 80 °C allows to obtain good results with all resins. The recovery of the heterogeneous catalyst during at least 11 reaction cycles avoids the drawbacks of the homogeneous ones including corrosion problems. In addition, this procedure can be applied to several epoxyfatty esters with different chain size, stereochemistry of the epoxide or with additional functionalities, obtaining good yields of structurally different polyols

MOBFLOW: Movilidad para los procesos de negocio de la organización

Este artículo presenta la plataforma MobFlow (Mobile Flow); un sistema que permite particionar, distribuir, y ejecutar en entornos móviles, procesos de negocio descritos a través del estándar BPEL. También, MobFlow realiza el monitoreo de la ejecución de los procesos de negocio de la organización, los cuales son consumidos en tiempo real en los dispositivos móviles de los empleados. Además de exponer los módulos que componen la plataforma, el artículo presenta la implementación de un prototipo que valida la arquitectura propuesta, y un caso de estudio práctico de un proceso de ventas, que expone el funcionamiento de la plataforma

Rheological properties of biofilms: steady and transient shear flow modeling

Premi al millor poster en la 7th Internacional Conference on Biotechniques for Air Pollution Control and BioenergyPeer ReviewedAward-winningPostprint (published version

Regioselective formation of\ud [2-(η5-cyclopentadienyl)-2-fluorenylpropane]-titanium complexes:\ud precursors, synthesis, structure and reactivity

The 2-cyclopentadienyl-2-fluorenylpropane ligand has been converted into the monometalated derivatives M[CMe2(C5H4)(C13H9)] (M=Li, Tl,) and CMe2[C5H4(SiMe3)](C13H9). These alkylating reagents have been characterized, and used to synthesize a new series of organotitanium (IV) complexes. The trimethylsilyl derivative was treated with TiCl4 to give the monocyclopentadienyl compound [Ti{CMe2(η5-C5H4)(C13H9)}Cl3]. Reaction of the thallium derivative with [Ti(η5-C5R5)Cl3] afforded the ‘mixed-ring’ dicyclopentadienyl complexes [Ti{CMe2(η5-C5H4)(C13H9)}(η5-C5R5)Cl2] (R=H, Me), whereas the reaction of TiCl4 with two equivalents of the lithium compound led to the dicyclopentadienyl complex [Ti{CMe2(η5-C5H4)(C13H9)}2Cl2]. The monocyclopentadienyl compound [Ti{CMe2(η5-C5H4)(C13H9)}Cl3] was readily hydrolyzed to give [Ti{CMe2(η5-C5H4)(C13H9)}Cl2]2(μ-O) in wet acetone (0.5% H2O). The dicyclopentadienyl derivative [Ti{CMe2(η5-C5H4)(C13H9)}(η5-C5Me5)Cl2] was further converted into [Ti{CMe2(η5-C5H4)(C13H9)}(η5-C5Me5)Me2] by alkylation with LiMe. Structural data of the titanium complexes demonstrate the η5-coordination of the cyclopentadienyl ring of the ancillary ligand, whereas the fluorenyl ring is not coordinated to the metal center. This mode of coordination is confirmed by the X-ray crystal structure analysis of [Ti{CMe2(η5-C5H4)(C13H9)}2Cl2]

Synthetic X-ray emission from white dwarf accreting planetary material

The emission of hard X-rays associated with white dwarfs (WD) can be generated by the presence of a stellar companion either by the companion's coronal emission or by an accretion disk formed by material stripped from the companion. Recent studies have suggested that a Jupiter-like planet can also be donor of material whose accretion onto the WD can generate hard X-rays. We use the {\sc guacho} code to reproduce the conditions of this WD-planet scenario. With the example of the hard X-ray WD KPD\,0005+5106, we explore different terminal wind velocities and mass-loss rates of a donor planet for a future network of simulations to investigate the luminosity and the spectral and temporal properties of the hard X-ray emission in WD-planet systems. Our simulations show that the material stripped from the planet forms a disk and accretes onto the WD to reach temperatures high enough to generate hard X-rays as usually seen in X-ray binaries with low-mass companions. For high terminal wind velocities, the planet material does not form a disk, but it rather accretes directly onto the WD surface. The simulations reproduce the X-ray luminosity of another X-ray accreting WD (G\,29$-$38), and only for some times reaches the hard X-ray luminosity of KPD\,0005+5106. The X-ray variability is stochastic and does not reproduce the period of KPD\,0005+5106, suggesting that additional physical processes (e.g., hot spots resulting from magnetic channelling of the accreting material) need to be explored.Comment: 16 pages, 13 figure

Slim LSTM networks: LSTM_6 and LSTM_C6

We have shown previously that our parameter-reduced variants of Long Short-Term Memory (LSTM) Recurrent Neural Networks (RNN) are comparable in performance to the standard LSTM RNN on the MNIST dataset. In this study, we show that this is also the case for two diverse benchmark datasets, namely, the review sentiment IMDB and the 20 Newsgroup datasets. Specifically, we focus on two of the simplest variants, namely LSTM_6 (i.e., standard LSTM with three constant fixed gates) and LSTM_C6 (i.e., LSTM_6 with further reduced cell body input block). We demonstrate that these two aggressively reduced-parameter variants are competitive with the standard LSTM when hyper-parameters, e.g., learning parameter, number of hidden units and gate constants are set properly. These architectures enable speeding up training computations and hence, these networks would be more suitable for online training and inference onto portable devices with relatively limited computational resources.Comment: 6 pages, 12 figures, 5 table

STEREOMICROSCOPIC ANALYSIS OF PREHISTORY CERAMIC: A REVIEWED GUIDE ABOUT PRODUCTION PHASES DESCRIPTION

Se presenta una propuesta metodológica para el análisis macroscópico de cerámicas arqueológicas mediante estereomicroscopía. El fin de estos análisis es poder identificar las trazas originadas en su proceso de producción. Se trata de analíticas asequibles a cualquier investigador que reportan gran cantidad de información como estudio preliminar a trabajos más profundos sobre tecnología de manufactura cerámica.We present a proposal method to macroscopic analysis of archaeological ceramics with stereomicroscopic. The purpose of this analysis is to identify the trace caused during the production process. They are accessible to any researcher reporting a lot of information about the manufacturing ceramic technology as a preliminary study to deeper work

Factors Affecting Embryo Recovery Rate, Quality, and Diameter in Andalusian Donkey Jennies

Embryo transfer and the vitrification of embryos could be used for the conservation and recovery of endangered donkey breeds. It is important to develop techniques that optimize recovery rates and the cryotolerance of donkey embryos. This study evaluates factors affecting the recovery rate, quality, and diameter of embryos obtained from donor jennies as a starting point for the use of vitrification and embryo transfer in the conservation of the Andalusian donkey. A total of 100 embryos were recovered out of 124 estrous cycles (80.6%). The donor jenny affected the rates of positive flushings (PFR; p = 0.040) and embryo recovery (ERR; p < 0.05) as well as embryo quality (p = 0.004). ERR was also affected by the number of flushings (p < 0.001), donor age (p < 0.05), successive cycle within donor (p < 0.001), and jacks (p < 0.05). Number of flushings (p < 0.001) and jack (p < 0.05) had a significant effect on PFR, whereas the day of flushing influenced the developmental stage (p < 0.001), embryo quality (p < 0.05), and diameter of embryos (p < 0.001). The number of flushings significantly influenced the diameter (p = 0.038) and embryo developmental stage (p = 0.001), whereas the developmental stage was statistically different between herds (p = 0.020). The factors influencing the success of this assisted reproductive technique were donor jenny, donor age, successive cycle within donor, day of flushing, number of flushings, and jack. The identification of these key points is crucial to achieve a higher efficiency of embryo transfer and vitrification processes, before considering their application in the conservation of endangered donkey breeds