1,094 research outputs found

    Biodegradación de los componentes de mayor impacto en la gasolina

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    El benceno, tolueno, etilbenceno y la mezcla de xilenos (BTEX), junto con éter metil tert-butílico (EMTB) son compuestos orgánicos volátiles, estos junto con el etanol comúnmente son encontrados en sitios contaminados con gasolinas. En este estudio se evaluó la biodegradación de estos contaminantes mediante consorcios microbianos aclimatados a diferentes sustratos (diesel, gasolina, EMTB, pentano y pentano-EMTB) en sistemas aerobios de lote y de biopelícula de flujo continuo. A partir de éste ultimo sistema se lograron los máximos porcentajes de biodegradación que fueron casi de 100% para cada uno de los BTEX y etanol; y de 67.76% para el EMTB, a un tiempo de retención hidráulico de doce horas

    Combined EXAFS, XRD, DRIFTS, and DFT Study of Nano Copper-Based Catalysts for CO2 Hydrogenation

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    Highly monodispersed CuO nanoparticles (NPs) were synthesized via continuous hydrothermal flow synthesis (CHFS) and then tested as catalysts for CO2 hydrogenation. The catalytic behavior of unsupported 11 nm sized nanoparticles from the same batch was characterized by diffuse reflectance infrared fourier transform spectroscopy (DRIFTS), extended X-ray absorption fine structure (EXAFS), X-ray diffraction (XRD), and catalytic testing, under CO2/H2 in the temperature range 25–500 °C in consistent experimental conditions. This was done to highlight the relationship among structural evolution, surface products, and reaction yields; the experimental results were compared with modeling predictions based on density functional theory (DFT) simulations of the CuO system. In situ DRIFTS revealed the formation of surface formate species at temperatures as low as 70 °C. DFT calculations of CO2 hydrogenation on the CuO surface suggested that hydrogenation reduced the CuO surface to Cu2O, which facilitated the formation of formate. In situ EXAFS supported a strong correlation between the Cu2O phase fraction and the formate peak intensity, with the maxima corresponding to where Cu2O was the only detectable phase at 170 °C, before the onset of reduction to Cu at 190 °C. The concurrent phase and crystallite size evolution were monitored by in situ XRD, which suggested that the CuO NPs were stable in size before the onset of reduction, with smaller Cu2O crystallites being observed from 130 °C. Further reduction to Cu from 190 °C was followed by a rapid decrease of surface formate and the detection of adsorbed CO from 250 °C; these results are in agreement with heterogeneous catalytic tests where surface CO was observed over the same temperature range. Furthermore, CH4 was detected in correspondence with the decomposition of formate and formation of the Cu phase, with a maximum conversion rate of 2.8% measured at 470 °C (on completely reduced copper), supporting the indication of independent reaction pathways for the conversion of CO2 to CH4 and CO that was suggested by catalytic tests. The resulting Cu NPs had a final crystallite size of ca. 44 nm at 500 °C and retained a significantly active surface

    In Vitro Model for Hepatotoxicity Studies Based on Primary Human Hepatocyte Cultivation in a Perfused 3D Bioreactor System

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    Accurate prediction of the potential hepatotoxic nature of new pharmaceuticals remains highly challenging. Therefore, novel in vitro models with improved external validity are needed to investigate hepatic metabolism and timely identify any toxicity of drugs in humans. In this study, we examined the effects of diclofenac, as a model substance with a known risk of hepatotoxicity in vivo, in a dynamic multi-compartment bioreactor using primary human liver cells. Biotransformation pathways of the drug and possible effects on metabolic activities, morphology and cell transcriptome were evaluated. Formation rates of diclofenac metabolites were relatively stable over the application period of seven days in bioreactors exposed to 300 µM diclofenac (300 µM bioreactors (300 µM BR)), while in bioreactors exposed to 1000 µM diclofenac (1000 µM BR) metabolite concentrations declined drastically. The biochemical data showed a significant decrease in lactate production and for the higher dose a significant increase in ammonia secretion, indicating a dose-dependent effect of diclofenac application. The microarray analyses performed revealed a stable hepatic phenotype of the cells over time and the observed transcriptional changes were in line with functional readouts of the system. In conclusion, the data highlight the suitability of the bioreactor technology for studying the hepatotoxicity of drugs in vitro

    A Fatal Case of Generalized Lysosomal Storage Disease in an Infant.

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    Gangliosidoses are a heterogeneous group of lysosomal storage diseases with an autosomal recessive trait, which are characterized by the intracellular accumulation of gangliosides in several tissues, mainly in neurons. This condition causes a progressive neurodegenerative disorder with varied clinical presentations. Depending on the severity of the enzymatic defect, gangliosidoses show different rates of clinical progression and organ involvement; poor residual enzyme activity is seen in more aggressive forms (infantile and juvenile subtypes) leading to early death whereas cases with better residual enzyme activity have a late onset in adult life and a milder clinical course. Autopsy findings of a 7 month-old girl with histological and ultrastructural changes consistent with gangliosidosis are presented

    Long-term assessment of wild boar harvesting and cattle removal for bovine tuberculosis control in free ranging populations

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    Wild boar is a recognized reservoir of bovine tuberculosis (TB) in the Mediterranean ecosystems, but information is scarce outside of hotspots in southern Spain. We describe the first high-prevalence focus of TB in a non-managed wild boar population in northern Spain and the result of eight years of TB management. Measures implemented for disease control included the control of the local wild boar population through culling and stamping out of a sympatric infected cattle herd. Post-mortem inspection for detection of tuberculosis-like lesions as well as cultures from selected head and cervical lymph nodes was done in 745 wild boar, 355 Iberian ibexes and five cattle between 2004 and 2012. The seasonal prevalence of TB reached 70% amongst adult wild boar and ten different spoligotypes and 13 MIRU-VNTR profiles were detected, although more than half of the isolates were included in the same clonal complex. Only 11% of infected boars had generalized lesions. None of the ibexes were affected, supporting their irrelevance in the epidemiology of TB. An infected cattle herd grazed the zone where 168 of the 197 infected boars were harvested. Cattle removal and wild boar culling together contributed to a decrease in TB prevalence. The need for holistic, sustained over time, intensive and adapted TB control strategies taking into account the multi-host nature of the disease is highlighted. The potential risk for tuberculosis emergence in wildlife scenarios where the risk is assumed to be low should be addressed

    The Origin of High Activity of Amorphous MoS2 in the Hydrogen Evolution Reaction

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    Molybdenum disulfide (MoS2) and related transition metal chalcogenides can replace expensive precious metal catalysts such as Pt for the hydrogen evolution reaction (HER). The relations between the nanoscale properties and HER activity of well‐controlled 2H and Li‐promoted 1T phases of MoS2, as well as an amorphous MoS2 phase, have been investigated and a detailed comparison is made on Mo−S and Mo−Mo bond analysis under operando HER conditions, which reveals a similar bond structure in 1T and amorphous MoS2 phases as a key feature in explaining their increased HER activity. Whereas the distinct bond structure in 1T phase MoS2 is caused by Li+ intercalation and disappears under harsh HER conditions, amorphous MoS2 maintains its intrinsic short Mo−Mo bond feature and, with that, its high HER activity. Quantum‐chemical calculations indicate similar electronic structures of small MoS2 clusters serving as models for amorphous MoS2 and the 1T phase MoS2, showing similar Gibbs free energies for hydrogen adsorption (ΔGH*) and metallic character

    Does eHealth Literacy Impact Patients' Opinion on the EHR?

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    An electronic health record (EHR) will be established nationwide in Switzerland in 2020. Patients can decide on their own whether they open an EHR. It is still unclear what might influence the patient decision. For this reason, we performed an online survey among the Swiss population to study whether there is a lack of knowledge on the EHR which impacts the willingness to open a personal health record and agree to health data sharing. A questionnaire with 13 question was distributed in a period of 4 weeks. More than 1200 participants replied to the survey. The results were analyzed with statistical methods. There are correlations between some of the questions in our survey. We conclude that the willingness to open a personal health record directly depends on the trust into the enabling technology
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