Search

Recent works in the development of nanostructured catalysts for bromate reduction in drinking water under hydrogen have highlighted the importance of the properties of the metallic phase support in their overall performance. Since most works in catalyst development are carried out in powder form, there is an overlooked gap in the correlation between catalyst support properties and performance in typical continuous applications such as fixed bed reactors. In this work, it is shown that the mechanical modification of commercially available carbon nanotubes, one of the most promising supports, can significantly enhance the activity of the catalytic system when tested in a stirred tank reactor, but upon transition to a fixed bed reactor, the formation of preferential pathways for the liquid flow and high pressure drops were observed. This effect could be minimized by the addition of an inert filler to increase the bed porosity; however, the improvement in catalytic performance when compared with the as-received support material was not retained. The operation of the continuous catalytic system was then optimized using a 1 wt.% Pd catalyst supported on the as-received carbon nanotubes. Effluent and hydrogen flow rates as well as catalyst loadings were systematically optimized to find an efficient set of parameters for the operation of the system, regarding its catalytic performance, capacity to treat large effluent flows, and minimization of catalyst and hydrogen requirements. Experiments carried out in the presence of distilled water as a reaction medium demonstrate that bromate can be efficiently removed from the liquid phase, whereas when using a real water matrix, a tendency for the deactivation of the catalyst over time was more apparent throughout 200 flow passages over the catalytic bed, which was mostly attributed to the competitive adsorption of inorganic matter on the catalyst active centers, or the formation of mineral deposits blocking access to the catalyst. [ABSTRACT FROM AUTHOR]

Abstract Gluten and water-soluble pentosans were extracted from defatted flours of two different wheat cultivars, having different grain hardness and baking quality. The rheological behaviour of the hydrated gluten samples and the effect of arabinoxylan-rich fractions of water-soluble pentosans (WSP) on their viscoelastic properties were studied in shear by dynamic measurements. The hydrated gluten samples showed the typical viscoelastic behaviour of a transient network, approaching the plateau zone at low frequencies. The WSP had only a small impact on this behaviour, causing a reinforcement of the network, as shown by the increase of storage modulus (G′), but also an increase in dissipative processes caused by a higher degree of structural rearrangements within the network, as shown by the higher frequency dependence of G′ and the higher value of the loss angle tangent. By interchanging the gluten and the WSP fractions of the two wheat varieties, it was shown that the observed effect was also dependent on the source from which the WSP originated. The glutens in the presence of WSP were also less sensitive to the thermal treatment than the glutens alone, as shown by the lower magnitude of variation of G′ with temperature. [ABSTRACT FROM AUTHOR]

Recent data have shown that owing to their seed-predator capacity Chiroderma doriae and Chiroderma villosum trophically depart from all previously studied species within the canopy fruit-bat ensemble. In this paper, the hypothesis that morphological adaptations related to granivory have evolved in these bats is investigated and discussed. A canonical variate analysis was used to search for possible divergent trends between the masticatory apparatus of Chiroderma and other stenodermatines currently recognized in the same ensemble. A total of 142 specimens representative of eight species was included in the analysis. Species of Chiroderma can be discriminated from all other species in the sample based on the increased development of masseter-related variables (height of the anterior zygomatic arch, masseter moment arm, and masseter volume), which, in conjunction with other morphological characteristics (dentition and gape angle) discussed herein, corroborates the evolution of durophagy in this group. A complementary analysis based on a Mantel test revealed that the pattern of morphological differentiation that emerged from the canonical variate analysis does not agree with the one expected based solely on the phylogenetic relationships adopted for the canopy fruit-bats studied here. This result is consistent with the hypothesis that morphological adaptations related to granivory have evolved in Chiroderma. [ABSTRACT FROM AUTHOR]

Summary The study of recovery of an extracellular alkaline protease from fermentation broth produced by Norcadiopsis sp, was carried out with liquid–liquid extraction through sodium di-(2-ethylhexyl) sulphosuccinate/isooctane reversed micelles systems and aqueous two-phase systems (polyethylene glycol/potassium phosphate). The best conditions for extraction and back-extraction with the reversed micelles system was obtained at pH 9.0 and pH 5.0, respectively, showing a yield of protein of 6.16%, a specific activity of 4.10 U/ml and a purification factor of 1.80. The studies using aqueous two-phase systems of polyethylene glycol/potassium phosphate at pH 10.0 showed purification factors of 2 and 5, and protein yield of 11 and 4%, respectively, for polyethylene glycol 550/potassium phosphate and polyethylene glycol 8000/potassium phosphate. The results indicate that the aqueous two-phase systems are more attractive as a first step in the isolation and purification processes. [ABSTRACT FROM AUTHOR]

The pattern of correlations between geographic–environmental variables and geometric shape descriptors for the skull and mandible of Thrichomys apereoides was studied by recently developed combinations of geometry and multivariate statistical techniques. Environmental variables were obtained for each locality: altitude, mean temperature, rainfall, human population density, and vegetation type. The three views of the skull (dorsal, lateral and ventral) and the mandible were significantly associated with a latitudinal environmental gradient along the diagonal of open areas (caatinga and cerrado) throughout the range sampled. The populations from xeric environments presented relatively larger coronoid processes, larger jugals and wider snouts (related to the activity of jaw closing muscles). A correlation of patterns of shape variation from data sets of different skull views showed that lateral skull shape is the most informative view. Further studies are necessary to separate completely the contribution of genetic and environmental components to skull and mandible shape divergence among populations of T. apereoides. [ABSTRACT FROM AUTHOR]

Traditional Iberian pig production is characterized by outdoor systems that produce animals fed with natural resources. The aim of this study was to assess the environmental impacts of such systems through Life Cycle Assessment. Environmental impacts were analysed per kilogram of live weight at farm gate. Iberian pig production in montanera had the lowest impacts for climate change (CC), acidification (AC), eutrophication (EU) and cumulative energy demand (CED), being 3.4 kg CO2 eq, 0.091 molc H+ eq, 0.046 kg PO43− eq, and 20.7 MJ, respectively, due to the strict use of natural resources (acorns and grass) during the fattening period. As Iberian farms had a greater dependence on compound feed in cebo campo, environmental impacts on CC, AC, EU and CED were 22, 17, 95 and 28% higher, respectively, than with montanera. For land occupation (LO), however, cebo campo had a lower impact (31.6 m2·year) than montanera (43.0 m2·year) system. Traditional Iberian pig production systems have environmental impacts higher than conventional systems studied in literature but are similar to other traditional systems. Based on the present assessment, it is necessary to account for the contribution of emissions resulting from the consumption of natural resources to avoid the underestimation of environmental impacts. [ABSTRACT FROM AUTHOR]