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Comprehending symbiont abundance among host species is a major ecological endeavour, and the metabolic theory of ecology has been proposed to understand what constrains symbiont populations. We parameterized metabolic theory equations to investigate how bird species' body size and the body size of their feather mites relate to mite abundance according to four potential energy (uropygial gland size) and space constraints (wing area, total length of barbs and number of feather barbs). Predictions were compared with the empirical scaling of feather mite abundance across 106 passerine bird species (26,604 individual birds sampled), using phylogenetic modelling and quantile regression. Feather mite abundance was strongly constrained by host space (number of feather barbs) but not by energy. Moreover, feather mite species' body size was unrelated to the body size of their host species. We discuss the implications of our results for our understanding of the bird-feather mite system and for symbiont abundance in general.
Assuntos
Doenças das Aves , Infestações por Ácaros , Ácaros , Passeriformes , Animais , Filogenia , Tamanho Corporal , Infestações por Ácaros/veterináriaRESUMO
The improvement of air quality in densely-populated urban regions constitutes an environmental challenge of increasing concern. In this respect, the abatement of NO emissions, primarily emanating from combustion processes associated with motor-vehicles, along with industrial/domestic combustion systems, represents one of the main problems. Here, three hydrochars from diverse organic residues were used as activated carbon precursors for their evaluation in the NO removal in two potential application scenarios. Hydrochars were physically activated at 800 °C with pure-CO2 or diluted-O2. These materials were tested in a lab-scale biofilter at different conditions (NO concentration, temperature, relative humidity, NO-containing gas and carbon particle size) and in a larger-scale biofilter to evaluate the long-term NO removal capacity. Hydrochar-derived carbons present a relatively well-developed micro- and mesoporous structure, with BET areas of up to 421 m2/g, and a variety of oxygen surface functionalities (carboxylic, lactone, carbonyl and quinone groups), especially concerning CO2-activated carbons. These exhibited an excellent behaviour at low NO concentration (5 ppmv) between 25 and 75 °C with removal capacities of ≈97 % and > 82 %, respectively; and still good-performance (≈66 %) in a more concentrated gas (120 ppmv). Whilst, carbons obtained by diluted-O2 activation from the same hydrochars, evidenced a higher removal capacity loss at high NO concentration. The O2 presence in the gas stream was confirmed as a crucial factor in the NO elimination, since both co-adsorb on the carbon surface favouring NO oxidation to NO2. Besides, the humidity in the airstream diminished the NO removal capacity from 0.88 to 0.51 mgNO/gcarbon, but still remained at 0.54 mgNO/gcarbon, when the carbon (in pellet) was operated at larger-scale biofilter in 9-fold longer test under humid air. Therefore, this study highlights the potential of renewable carbons to serve as cost-effective component in urban biofilters, to mitigate NO emissions from exhaust gases in biomass boilers and urban semi-close areas.
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The production of added-value chemicals via pyrolysis of plastic wastes, such as those from electrical and electronic equipment (WEEE), needs addressing their usual contamination with halogens (mainly Br and Cl). This work compares the conversion via pyrolysis and hydropyrolysis of a real WEEE plastic, having a complex composition, in two different reactor configurations: down-flow (DF) and up-flow (UF). Likewise, the effects of incorporating a Pd/Al2O3 catalyst and using two different pressures (1 and 6 bar) have been assessed. With the DF mode, pyrolysis at 1 bar leads to an oil yield above 80 wt% and a total halogen content of about 600 ppm (vs 1600 ppm in the water-washed WEEE plastic). Under DF catalytic hydropyrolysis at 6 bar, this high oil yield is maintained while its dehalogenation degree is improved (142 ppm). Operating with the up-flow configuration, under 6 bar and H2 presence, leads to some reduction in the oil yield (about 70 wt%) but significantly decreases the oil halogen content (55 ppm Cl and total elimination of Br). These results have been related to the slower pyrolysis and longer residence time in the thermal zone of the UF configuration, which favours the halogen-trapping effect of the char fraction, and the pressure-enhanced hydrodehalogenation activity of the catalyst. This study highlights the environmental benefits of the proposed process, emphasizing the lower halogen content in the resulting oils and promoting a more sustainable approach to plastic waste valorisation.
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The need to develop green and cost-effective industrial catalytic processes has led to growing interest in preparing more robust, efficient, and selective heterogeneous catalysts at a large scale. In this regard, microwave-assisted synthesis is a fast method for fabricating heterogeneous catalysts (including metal oxides, zeolites, metal-organic frameworks, and supported metal nanoparticles) with enhanced catalytic properties, enabling synthesis scale-up. Herein, the synthesis of nanosized UiO-66-NH2 was optimized via a microwave-assisted hydrothermal method to obtain defective matrices essential for the stabilization of metal nanoparticles, promoting catalytically active sites for hydrogenation reactions (760 kg·m-3·day-1 space time yield, STY). Then, this protocol was scaled up in a multimodal microwave reactor, reaching 86% yield (ca. 1 g, 1450 kg·m-3·day-1 STY) in only 30 min. Afterward, Pd nanoparticles were formed in situ decorating the nanoMOF by an effective and fast microwave-assisted hydrothermal method, resulting in the formation of Pd@UiO-66-NH2 composites. Both the localization and oxidation states of Pd nanoparticles (NPs) in the MOF were achieved using high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and X-ray photoelectron spectroscopy (XPS), respectively. The optimal composite, loaded with 1.7 wt % Pd, exhibited an extraordinary catalytic activity (>95% yield, 100% selectivity) under mild conditions (1 bar H2, 25 °C, 1 h reaction time), not only in the selective hydrogenation of a variety of single alkenes (1-hexene, 1-octene, 1-tridecene, cyclohexene, and tetraphenyl ethylene) but also in the conversion of a complex mixture of alkenes (i.e., 1-hexene, 1-tridecene, and anethole). The results showed a powerful interaction and synergy between the active phase (Pd NPs) and the catalytic porous scaffold (UiO-66-NH2), which are essential for the selectivity and recyclability.
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Objetivo. Caracterizar flavonoides presentes en el extracto y subextracto metanólico de las hojas de Apium graveolens var. Rapaceum, DC. "Apio-nabo". Materiales y métodos. Se elaboró un extracto y subextracto metanólico de las hojas Apium graveolens var. Rapaceum, DC. "Apio-nabo". Se determinó la solubilidad del extracto metanólico en solventes de polaridad creciente. Se detectaron los componentes químicos del extracto y subextracto metanólico mediante un tamizaje fitoquímico empleando gelatina, tricloruro férrico, reactivo de Shinoda, reactivo de Dragendorff y reactivo de Ninhidrina, entre otros. Se ejecutó cromatografía en capa fina y mediante espectroscopia UV/Vis se propuso estructuras químicas para los metabolitos tipo flavonoides presentes en el extracto y subextracto metanólico de hojas de Apium graveolens var. Rapaceum, DC. "Apio-nabo". Resultados. El extracto metanólico de hojas de Apium graveolens var. Rapaceum, DC fue soluble en solventes polares. Los metabolitos secundarios encontrados son compuestos fenólicos tipo flavonoides, taninos y alcaloides en el extracto y subextracto metanólico. Se propuso tres estructuras químicas de flavonoides a través del análisis de los espectros UV/Vis, y mediante comparación con lo publicado por TJ Mabry y Olga Lock. Conclusión. Se caracterizó la posible estructura química de tres metabolitos secundarios tipo flavona encontrados en el subextracto metanólico de hojas de Apium graveolens var. Rapaceum, DC.
Objective. To characterize flavonoids present in the methanol extract and subextract of the leaves of Apium graveolens var. Rapaceum, DC. "Celery-turnip". Materials and methods. An methanolic extract and subextract of Apium graveolens var. Rapaceum, DC. "Celery-turnip" was prepared. The solubility of the methanolic extract in solvents of increasing polarity was determined. The chemical components of the methanolic extract and subextract were detected by means of a phytochemical screening using gelatin, ferric trichloride, Shinoda reagent, Dragendorff reagent and Ninhydrin reagent, among others. Thin layer chromatography was carried out and by means of UV / Vis spectroscopy chemical structures were proposed for the flavonoid metabolites present in the methanolic extract and subextract of Apium graveolens var. Rapaceum, DC. "Celery-turnip". Results. It was determined that the methanolic extract of the leaves of Apium graveolens var. Rapaceum, DC. is soluble in polar solvents. The metabolites, the phenolic compounds, the flavonoids, the tannins and the alkaloids in the extract and methanol subextract. Flavonoid chemical structures are proposed through the analysis of the UV / Vis spectra, and it has been published with TJ Mabry and Olga Lock. Conclusion. The possible chemical structure of three secondary flavone metabolites found in methanolic subextract of leaves of Apium graveolens var. Rapaceum, DC.
Assuntos
Flavonoides , Apium/química , Plantas Medicinais , Análise Espectral , Extratos Vegetais , Cromatografia , Medicina TradicionalRESUMO
Abstract Lynch syndrome is the most common cause of inherited colorectal cancer, totaling 5 to 8% of all the cases with high susceptibility to this type of cancer and extracolonic cancer. It is related to germinal mutations taking place at mismatch repair genes. The diagnosis of Lynch syndrome is essential for both monitoring patients with this disease and detecting asymptomatic carriers, in order to establish appropriate clinical monitoring, preventive management and genetic counseling. Although clinical criteria have been standardized by implementing Amsterdam I and II, as well as Bethesda guidelines, the detection rate of mutations in these genes only varies between 20% and 60%. The objective of this research was to review the state of the art regarding molecular diagnosis of Lynch syndrome; thus, a review of the literature published from 1995 to 2015 in PubMed database was performed by using the criteria "lynch syndrome molecular screening". 19 articles were selected and reviewed, and the relevant bibliography related to such articles was also reviewed. This paper presents different approaches proposed by several researchers on molecular algorithms to improve the efficiency of Lynch syndrome diagnosis.
Resumen El síndrome de Lynch es la causa más frecuente de cáncer colorectal (CCR) hereditario y representa el 5-8% de los casos con alta susceptibilidad a CCR y cánceres extracolónicos. Este síndrome se relaciona con mutaciones germinales en genes de reparación de malos apareamientos (MMR); su diagnóstico es fundamental, tanto para el seguimiento de los afectados como para la detección de portadores asintomáticos, y tiene el propósito de instaurar un adecuado seguimiento, un manejo preventivo y un asesoramiento genético. Si bien los criterios clínicos han sido estandarizados con la implementación de las guías de Amsterdam I y II y Bethesda, la tasa de detección de mutaciones en estos genes solo varía entre 20% y 60%. El objetivo de esta investigación fue revisar el estado del arte con relación al diagnóstico molecular del síndrome de Lynch, para lo cual se realizó una revisión de la literatura publicada entre 1995 y 2015 en la base de datos PubMed usando como criterio de revisión: "Lynch syndrome molecular screening". Se escogieron y revisaron 19 artículos y además se revisó y escogió la bibliografía pertinente de los artículos. Se presentan propuestas de varios autores sobre los algoritmos moleculares para mejorar la eficiencia del diagnóstico del síndrome de Lynch.