Effect of pH on the denitrification proteome of the soil bacterium Paracoccus denitrificans PD1222

Denitrification is a respiratory process by which nitrate is reduced to dinitrogen. Incomplete denitrification results in the emission of the greenhouse gas nitrous oxide and this is potentiated in acidic soils, which display reduced denitrification rates and high N 2O/N 2 ratios compared to alkaline soils. In this work, impact of pH on the proteome of the soil denitrifying bacterium Paracoccus denitrificans PD1222 was analysed with nitrate as sole energy and nitrogen source under anaerobic conditions at pH ranging from 6.5 to 7.5. Quantitative proteomic analysis revealed that the highest difference in protein representation was observed when the proteome at pH 6.5 was compared to the reference proteome at pH 7.2. However, this difference in the extracellular pH was not enough to produce modification of intracellular pH, which was maintained at 6.5 ± 0.1. The biosynthetic pathways of several cofactors relevant for denitrification and nitrogen assimilation like cobalamin, riboflavin, molybdopterin and nicotinamide were negatively affected at pH 6.5. In addition, peptide representation of reductases involved in nitrate assimilation and denitrification were reduced at pH 6.5. Data highlight the strong negative impact of pH on NosZ synthesis and intracellular copper content, thus impairing active NosZ assembly and, in turn, leading to elevated nitrous oxide emissions

Adelante / Endavant

Séptimo desafío por la erradicación de la violencia contra las mujeres del Institut Universitari d’Estudis Feministes i de Gènere "Purificación Escribano" de la Universitat Jaume

Olive Leaves as Biotemplates for Enhanced Solar-Light Harvesting by a Titania-Based Solid

Olive leaves (by-product from olive oil production in olive mills) were used as biotemplates to synthesize a titania-based artificial olive leaf (AOL). Scanning electron microscopy (SEM) images of AOL showed the successful replication of trichomes and internal structure channels present in olive leaves. The BET surface area of AOL was 52 m2·g−1. X-ray diffraction (XRD) and Raman spectra revealed that the resulting solid was in the predominantly-anatase crystalline form (7.5 nm average particle size). Moreover, the synthesis led to a red-shift in light absorption as compared to reference anatase (gap energies of 2.98 and 3.2 eV, respectively). The presence of surface defects (as evidenced by X-ray photoelectron spectroscopy, XPS, and electron paramagnetic resonance spectroscopy, EPR) and doping elements (e.g., 1% nitrogen, observed by elemental analysis and XPS) could account for that. AOL was preliminarily tested as a catalyst for hydrogen production through glycerol photoreforming and exhibited an activity 64% higher than reference material Evonik P25 under solar irradiation and 144% greater under ultraviolet radiation (UV)

Ergonomía y odontología

Se muestran conceptos básicos que tienen relación con el mundo de la ergonomía aplicada al campo odontológico. [ABSTRACT]Showing basic concepts that relate to the world of ergonomics applied to the dental field

Equipamiento en odontología

Se presentan los conceptos básicos que tienen relación con el equipamiento y las instalaciones propias de la práctica odontológica. [ABSTRACT]We present the basic concepts that are related to equipment and facilities of the dental practice

MPV Reduction of Furfural to Furfuryl Alcohol on Mg, Zr, Ti, Zr–Ti, and Mg–Ti Solids: Influence of Acid–Base Properties

The Meerwein⁻Ponndorf⁻Verley (MPV) reaction is an environmentally-friendly process consisting of the reduction of a carbonyl compound through hydrogen transfer from a secondary alcohol. This work deals with MPV reduction of furfural to furfuryl alcohol on different ZrOx, MgOx, TiOx, and Mg⁻Ti, as well as Zr⁻Ti mixed systems. The solids were synthesized through the sol⁻gel process and subsequently calcined at 200 °C. Characterization was performed using a wide range of techniques: ICP-MS, N2 adsorption-desorption isotherms, EDX, TGA-DTA, XRD, XPS, TEM, TPD of pre-adsorbed pyridine (acidity) and CO2 (basicity), DRIFT of adsorbed pyridine, and methylbutynol (MBOH) test reaction. ZrOx showed the highest conversion and selectivity values, which was attributed to the existence of acid⁻base pair sites (as evidenced by the MBOH test reaction), whereas the introduction of titanium resulted in the drop of both conversion and selectivity probably due to the increase in Brönsted-type acidity. As for MgOx, it had a predominantly basic character that led to the production of the condensation product of one molecule of furfural and one molecule of acetone, and thus resulted in a lower selectivity to furfuryl alcohol. The TiOx solid was found to be mainly acidic and exhibited both Lewis and Brönsted acid sites. The presence of the latter could account for the lower selectivity to furfuryl alcohol. All in all, these results seemed to suggest that the MPV reaction is favored on Lewis acid sites and especially on acid⁻base pair sites. The process was accelerated under microwave irradiation

Cernícalo vulgar

SEO/BirdLife (López-Jiménez N. Ed). 2021. Libro Rojo de las aves de España.Especie generalista en el uso de hábitats abiertos. Puede encontrarse en acantilados, ecosistemas agroesteparios, semidesiertos, zonas agrícolas, ganaderas, bosques poco densos y zonas antrópicas. Presenta una gran variedad de hábitats de cría, incluyendo pastizales, bosques abiertos y ambientes urbanos, con todos los gradientes posibles entre ellos, siendo el hábitat óptimo las áreas agrícolas y pastizales tradicionales (Village, 1990). En general, evita las masas arbóreas densas y necesita de espacios abiertos para cazar, especialmente herbazales y terrenos baldíos.El cernícalo vulgar está ampliamente distribuido en España, ocupando prácticamente la totalidad de la península ibérica, islas Baleares e islas Canarias, grandes grupos de mayor densidad en España: Castilla-León, excluyendo su parte más oriental; el centro-oeste de Andalucía. Una menor abundancia se podría destacar en Galicia y Asturias, el eje comprendido entre Guadalajara, Cuenca, Albacete y Murcia, la parte occidental de Extremadura y por último su baja densidad en el corredor comprendido entre Ávila, Toledo, Ciudad Real y Córdoba. En las islas Canarias está ampliamente distribuido, llegando a alcanzar elevadas densidades según las islas, siendo inferior en las orientales (Martín y Lorenzo 2001; Carrillo, 2007). La distribución invernal es irregular, con una más alta y continua ocupación en la meseta norte y la depresión del Guadalquivir, seguido de la meseta sur y la depresión del Ebro. En tercer lugar, destacan varias comarcas de Badajoz y del litoral mediterráneo. Es muy escaso en Galicia, la cornisa Cantábrica y en todos los sistemas montañosos (Palomino, 2012), aunque su presencia puede detectarse hasta a una altitud de 2.400 m en Pirineos y Canarias.Libro Rojo de las aves de España. Este proyecto cuenta con el apoyo del Ministerio para la Transición Ecológica y el Reto Demográfico, a través de la Fundación Biodiversidad.Peer reviewe

Microemulsion and Sol-Gel Synthesized ZrO2-MgO Catalysts for the Liquid-Phase Dehydration of Xylose to Furfural

Two series of catalysts were prepared by sol-gel and microemulsion synthetic procedure (SG and ME, respectively). Each series includes both pure Mg and Zr solids as well as Mg-Zr mixed solids with 25%, 50% and 75% nominal Zr content. The whole set of catalysts was characterized from thermal, structural and surface chemical points of view and subsequently applied to the liquid-phase xylose dehydration to furfural. Reactions were carried out in either a high-pressure autoclave or in an atmospheric pressure multi-reactor under a biphasic (organic/water) reaction mixture. Butan-2-ol and toluene were essayed as organic solvents. Catalysts prepared by microemulsion retained part of the surfactant used in the synthetic procedure, mainly associated with the Zr part of the solid. The MgZr-SG solid presented the highest surface acidity while the Mg3Zr-SG one exhibited the highest surface basicity among mixed systems. Xylose dehydration in the high-pressure system and with toluene/water solvent mixture led to the highest furfural yield. Moreover, the yield of furfural increases with the Zr content of the catalyst. Therefore, the catalysts constituted of pure ZrO2 (especially Zr-SG) are the most suitable to carry out the process under study although MgZr mixed solids could be also suitable for overall processes with additional reaction steps

Synthesis of Fe-TiO₂ and Cu-TiO₂ Based Materials by Olive Leaves Biotemplating—Application to Hydrogen Production from Glycerol Photoreforming

Hydrogen production is mainly based on the use of fossil fuels, but currently, many alternative routes are being developed, among which the photo-reforming of oxygenated organic compounds stands out. Recently, several studies have been carried out in order to develop new techniques to create bio-inspired TiO2 structures. One of these is ‘biotemplating’, a process that replicates a biological system in an inorganic TiO2-based structure. In this study, olive by-products—olive leaves—are valorized as a biotemplate for the synthesis of new Fe-TiO2- and Cu-TiO2-based photocatalysts with the aim of improving the replication of the leaf structure and enhancing hydrogen photoproduction. In conclusion, the incorporation of iron and copper decreases the band gap and increases the energetic disorder at the band edges. Moreover, it is verified by SEM and TEM that the metals are not found forming particles but are introduced into the formed TiO2 structure. The accuracy of the internal and external structure replication is improved with the incorporation of Fe in the synthesis, while the incorporation of Cu substantially improves the production of hydrogen, which is multiplied 14 times under UV light and 6 times under sunlight, as compared to a pure TiO2 structure

Aldol Condensation of Furfural with Acetone Over Mg/Al Mixed Oxides. Influence of Water and Synthesis Method

Aldol condensation of furfural and acetone (an important initial step to obtain diesel from biomass) was studied over MgAl mixed oxides. The influence of the utilization of microwaves and/or a surfactant (Pluronic 123) during the synthesis as well as the use of water (either pre-hydrating the solids before catalytic studies or in water/toluene mixtures as the reaction medium) is discussed. The combined use of Pluronic 123 and microwaves led to solids with bigger pore sizes, exhibiting lower basicity and higher acidity than the conventional synthetic method, thus resulting in an increase in the yield of the desired product of condensation, comprising two molecules of furfural and one of acetone (F2Ac). As for the influence of water, re-hydration of the mixed oxides was detrimental to activity, probably as a result of the partial blocking (solvation) of active sites. On the contrary, the increase in water percentage in the reaction medium resulted in higher conversions, though selectivity to F2Ac decreased. The weakening of the C=O bond of furfural in the presence of water as well as the higher solubility of the first condensation product (FAc) in toluene, as compared to water, could account for that. A 44.5% yield of F2Ac (66% conversion) after 16 h was obtained with the most active solid, which maintained the activity for three consecutive reactions