1,040 research outputs found
Proposing a new batch method for assessment of biological activity in H2S degrading biotrickling filters
[Abstract] The proposed batch method consists on measuring the sulfate production rate (SPR) at maximum rate of a set of polyurethane cubes extracted from an ongoing pilot-scale biotrickling filter (BTF) for hydrogen sulfide (H2S) removal. Saturation of the system was achieved by applying high gaseous pollutant concentrations. Under these operational conditions the measured activity is proportional to the concentration of H2S degrading biomass (XSH) present in the system. This method has been used to follow the performance of a pilot-scale BTF under selected conditions. The activity at the inlet zone of the packed bed was found to be between two and three times that measured at the outlet zone. An increase in elimination capacity of 14% corresponded to a very similar average activity increase in the reactor. In addition to this, the method provided a means by which the reactor recovery after a starvation period could be studied
The El Guijo Pluton: petrology, geochemistry, age and relation to others rocks of Los Pedroches batholith
[Resumen] El plutón de El Guijo es uno de los plutones ácidos circunscritos, intrusivos en las granodioritas que constituyen los tercios central y occidental del batolito de Los Pedroches. Con forma subelíptica, presenta una zonación centrípeta que va desde facies marginales graníticas biotíticas (localmente con microadamellitas porfídicas), marcadamente porfídicas, hasta facies centrales de leucogranitos cordieríticos (± moscovita). Geoquímicamente, las rocas de este plutón definen una asociación peraluminosa, con evolución netamente calcoalcalina. Se presentan los resultados de una datación (Rb-SR, roca total) que definen una isocrona de 300 ± 6 Ma, con (87 Sr/86 Sr) o de 0.704. Finalmente, se discuten sus relaciones y significado en el contexto general del batolito de Los Pedroches.[Abstract] The El Guijo pluton belongs to a group of centred, acidic plutons which intrude the ranodiorites making the most part of the Pedroches Batholith central and western thirds. It has a sub-elliptical shape and shows a centripetal zonation which ranges between marginal, biotite-bearing porphyritic granitic facÍes (locally intruding porphyritic micro-adamellites) and central cordierite -bearing leucogranites (± muscovite). They collectively define a peraluminous association with a neat calcalkaline evolution. The results of a Rb-Sr whole-rock study are presented. These define a 300 ±6 Ma age isochron with (87 Sr/86 Sr) o = 0.704. Finally, its relationships with, and its significance in the context of the overall Pedroches Batholith are discused
Continuous synthesis of drug-loaded nanoparticles using microchannel emulsification and numerical modeling: Effect of passive mixing
By using interdigital microfluidic reactors, monodisperse poly(d, l lactic-co-glycolic acid) nanoparticles (NPs) can be produced in a continuous manner and at a large scale (~10 g/h). An optimized synthesis protocol was obtained by selecting the appropriated passive mixer and fluid flow conditions to produce monodisperse NPs. A reduced NP polydispersity was obtained when using the microfluidic platform compared with the one obtained with NPs produced in a conventional discontinuous batch reactor. Cyclosporin, an immunosuppressant drug, was used as a model to validate the efficiency of the microfluidic platform to produce drug-loaded monodisperse poly(d, l lactic-co-glycolic acid) NPs. The influence of the mixer geometries and temperatures were analyzed, and the experimental results were corroborated by using computational fluid dynamic three-dimensional simulations. Flow patterns, mixing times, and mixing efficiencies were calculated, and the model supported with experimental results. The progress of mixing in the interdigital mixer was quantified by using the volume fractions of the organic and aqueous phases used during the emulsification–evaporation process. The developed model and methods were applied to determine the required time for achieving a complete mixing in each microreactor at different fluid flow conditions, temperatures, and mixing rates
The asymmetric cyclical behaviour of female labour force participation in Latin America
This study measures the responsiveness of female labour participation to changes in the economic cycle at the extensive margin in Latin America. The results provide new evidence regarding the cyclical behaviour of the female labour force participation, making it possible to determine which countries validate the traditional hypotheses of the added and discouraged worker. Another significant finding is that these effects vary during cycles of economic expansion and recession and become stronger when reaching a certain threshold. Therefore, contradictory hypotheses to the added and discouraged worker emerged, which is referred to as subtracted and encouraged workers, both of which are formally validated by examining these effects throughout the economic cycles
Selectable Markers and Reporter Genes for Engineering the Chloroplast of Chlamydomonas reinhardtii
Chlamydomonas reinhardtii is a model alga of increasing interest as a cell factory for the production of valuable compounds, including therapeutic proteins and bioactive metabolites. Expression of foreign genes in the chloroplast is particularly advantageous as: (i) accumulation of product in this sub-cellular compartment minimises potential toxicity to the rest of the cell; (ii) genes can integrate at specific loci of the chloroplast genome (plastome) by homologous recombination; (iii) the high ploidy of the plastome and the high-level expression of chloroplast genes can be exploited to achieve levels of recombinant protein as high as 5% total cell protein; (iv) the lack of any gene silencing mechanisms in the chloroplast ensures stable expression of transgenes. However, the generation of C. reinhardtii chloroplast transformants requires efficient methods of selection, and ideally methods for subsequent marker removal. Additionally, the use of reporter genes is critical to achieving a comprehensive understanding of gene expression, thereby informing experimental design for recombinant applications. This review discusses currently available selection and reporter systems for chloroplast engineering in C. reinhardtii, as well as those used for chloroplast engineering in higher plants and other microalgae, and looks to the future in terms of possible new markers and reporters that will further advance the C. reinhardtii chloroplast as an expression platform
INFLUENCIA DE LAS ORGANIZACIONES DE PRODUCTORES EN LOS RESULTADOS PRODUCTIVOS Y ECONÓMICOS EN EL CULTIVO DE FRUTILLA EN LA COMPAÑÍA ESTANZUELA DE ITAUGUÁ.
El estudio consistió en analizar aspectos que influyen en la rentabilidad de la producción de frutillas en la compañía Estanzuela, distrito de Itauguá. La metodología utilizada fue la aplicación de encuestas. Fueron entrevistados productores que forman parte de alguna asociación u organización y productores que trabajan individualmente. Los resultados demuestran la influencia de la participación de las asociaciones en la rentabilidad del rubro, donde los productores asociados obtienen mayor rentabilidad en la producción de frutilla con respecto a la rentabilidad obtenida por los productores individuales
The unemployment invariance hypothesis and the implications of added and discouraged worker effects in Latin America
This research explores the long-term equilibrium relationship between unemployment and labour force participation rates for six selected countries in Latin America at both aggregate and gender-disaggregated levels. Cointegration analysis focused on the study of time series is used to validate the unemployment invariance hypothesis and explore added and discouraged worker effects in depth. The results suggest mixed dynamics for the aggregate model; however, a clear gender bias is revealed towards the added worker effect for women, while the discouraged worker effect is confirmed for men. The validity of the unemployment invariance hypothesis in several countries appears to reflect some rigidities that prevent the improvement of nations’ labour markets, exposing issues that economic policies must strategically address
Mutational profiling can identify laryngeal dysplasia at risk of progression to invasive carcinoma
DNA-binding miniproteins based on zinc fingers. Assessment of the interaction using nanopores
Obtaining artificial proteins that mimic the DNA binding properties of natural transcription factors could open new ways of manipulating gene expression at will. In this context it is particularly interesting to develop simple synthetic systems. Inspired by the modularity of natural transcription factors, we have designed synthetic miniproteins that combine the zinc finger module of the transcription factor GAGA and AT-hook peptide domains. These constructs are capable of binding to composite DNA sequences of up to 14 base pairs with high affinity and good selectivity. In particular, we have synthesized three different chimeras and characterized their DNA binding properties by electrophoresis and fluorescence anisotropy. We have also used, for the first time in the study of peptide-based DNA binders, nanopore force spectroscopy to obtain further data on the DNA interaction
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