Enzymatic oligomerization and polymerization of arylamines: state of the art and perspectives

The literature concerning the oxidative oligomerization and polymerization of various arylamines, e.g., aniline, substituted anilines, aminonaphthalene and its derivatives, catalyzed by oxidoreductases, such as laccases and peroxidases, in aqueous, organic, and mixed aqueous organic monophasic or biphasic media, is reviewed. An overview of template-free as well as template-assisted enzymatic syntheses of oligomers and polymers of arylamines is given. Special attention is paid to mechanistic aspects of these biocatalytic processes. Because of the nontoxicity of oxidoreductases and their high catalytic efficiency, as well as high selectivity of enzymatic oligomerizations/polymerizations under mild conditions-using mainly water as a solvent and often resulting in minimal byproduct formation-enzymatic oligomerizations and polymerizations of arylamines are environmentally friendly and significantly contribute to a "green'' chemistry of conducting and redox-active oligomers and polymers. Current and potential future applications of enzymatic polymerization processes and enzymatically synthesized oligo/polyarylamines are discussed

Daily intake of a bean-fiber fortified bar reduces oxidative stress

It has been proposed that the consumption of common beans (Phaseolus vulgaris L.) reduces cardiovascular risk, and prevents and controls both chronic and degenerative diseases. The aim of this study was to compare the antioxidant capacity of a bean-fiber fortified bar (BFB) versus a commercial bar (CB) in 60 Mexican men and women (18-65 years old), who were randomly distributed in two groups: BFB or CB; individuals consumed a bar a day for one month. Anthropometric data, food intake and blood samples were collected. Glucose tolerance (GTT), lipid profile (PL), and lipid peroxidation (TBARS) tests were performed; carbonyls groups in serum oxidized proteins were also measured. GTT and PL were not different between both groups in either the 15 or 30-day follow-up of bar consumption assessments. There were no significant differences in either TBARS or carbonyl concentration between groups; BFB group showed higher levels of serum lipid peroxidation in basal and fifteen days measurements; these levels decreased at the final evaluation: No differences were detected on carbonyl levels between groups. In conclusion, 30 days of fiber bean bar consumption did not alter glucose or PL levels, while, in the BFF group, oxidative stress decreased within 30 days of the consumption of the fortified bar.Se ha propuesto que el consumo de frijol común (Phaseolus vulgaris L.) reduce el riesgo cardiovascular, y previene y controla las enfermedades crónicas y degenerativas. El objetivo del presente estudio fue comparar la capacidad antioxidante de una barra fortificada con fibra de frijol (BFB) versus una barra comercial (CB) en 60 hombres y mujeres mexicanos (18-65 años de edad), quienes aleatoriamente fueron distribuidos en dos grupos: El grupo BFB y el CB que consumieron la barras fortificada con frijol y la barra comercial, respectivamente, durante un mes. Se recopilaron datos antropométricos, ingesta de alimentos y muestras de sangre. Se realizó prueba de tolerancia a la glucosa (GTT), el perfil de lípidos (PL), la peroxidación de lípidos (TBARS) y la cuantificación de carbonilos en proteínas oxidadas como pruebas de bioquímica sanguínea. GTT y PL no fueron diferentes entre ambos grupos en la evaluación de seguimiento de 15 y 30 días del consumo de la barra. No hubo diferencias significativas en los TBARS o la concentración de carbonilo entre los grupos, el grupo BFB mostró niveles más altos de peroxidación de lípidos en suero en la fase basal y a los quince días del consumo de la barra; curiosamente, estos niveles disminuyeron en la evaluación final. No se detectaron diferencias en los niveles de carbonilo entre los grupos. En conclusión, 30 días de consumo de barras de fibra de frijol no alteraron los niveles de glucosa o PL; mientras que, en el grupo BFB, el estrés oxidativo disminuyó a los 30 días del consumo de la barra fortificada

Halloysite nanotube supported Ru nanocatalysts synthesized by the inclusion of preformed Ru nanoparticles for preferential oxidation of CO in H 2-rich atmosphere

The small-sized and well-dispersed Ru nanocatalysts supported on halloysite nanotubes (HNTs) were synthesized by the inclusion of preformed Ru nanoparticles onto HNTs (Ru NPs/HNTs) and employed for the preferential oxidation of CO in H-rich atmosphere (PROX). Polyol reduction was adopted to prepare Ru nanoparticles, and the synthesis conditions affected the morphology of the resulting nanoparticles. The catalysis results show that the Ru NPs/HNTs present significantly higher CO conversion and CO selectivity than the catalyst prepared by traditional wet impregnation. RuCl is a better Ru precursor than Ru(acac) for synthesizing Ru nanoparticles with higher catalytic reactivity. The catalytic performance of Ru NPs/HNTs can be further enhanced by the reduction pretreatment due to the removal of polyvinylpyrrolidone (PVP) capping on the surface of Ru nanoparticles, and this enhancement is more significant with reduction at 400 °C than at 200 °C. Finally, the characterizations on the used catalysts indicate that the morphology of Ru nanoparticles is maintained after PROX reaction; slight growth of particle size is observed with 200 °C reduction pretreatment, yet Ru nanoparticles lose their original size and shape with 400 °C reduction