The full-length cDNA of catalase (EfCAT) from Eisenia fetida was cloned (GenBank accession no. JN617999). Sequence characterization revealed that EfCAT protein sequence contained proximal heme-ligand signature sequence (351RLFSYSDTH359), two glycosylation sites (N145 and N436), the proximal active site signature (61FDRERIPERVVHAKGAGA78), and 12 amino acids (N145, H191, F195, S198, R200, N210, Y212, K234, I299, W300, Q302, and Y355), which were identified as putative residues involved in NADPH binding. These conserved motifs and catalase signature sequences were essential for the structure and function of EfCAT. The present study also investigated the effect of the veterinary food additive zinc oxide on antioxidant processes in E. fetida, at different concentrations and exposure durations. A significant increase (by 106.0 % compared to controls) in CAT activity at 500 mg/kg was registered at day 15. The superoxide dismutase (SOD) activity at 500 mg/kg increased to the maximum value (by 44.0 %) measured at day 15. There was a significant increase in glutathione peroxidase (GPx) activity for all concentrations after 5 days. The results showed that dietary Zn (500 mg/kg) causes oxidative damage to earthworms. At early stages of earthworms exposed to ZnO, GPx is the main enzyme to impair the oxidative status; while at later stages the enzymes CAT and SOD were the main indicators of oxidative stress. The antioxidant enzymatic variations may be an adaptive response of earthworms to survive in contaminated soils. 相似文献
Carbonyl iron/epoxy coatings are widely used in military as a radar absorbing coating (RAC). The behaviors of RACs under working
environments are very important, especially in the new environments such as ozone appeared with widening of the application
fields. The effects of ozone degradation on pure epoxy cured with anhydride and the influence of carbonyl Fe on the degradation
of epoxy are studied. The results indicate that if the peak at 1,510 cm−1 was used as the inner standard, the intensity of absorption peaks at 1,738, 1,247 and 1,182 cm−1 increases with exposure time for pure epoxy resin, while for the carbonyl iron/epoxy coatings, the three peaks changes insignificantly
with the exposure time. The results indicates the oxidation process begins at the hydroxyl and methyl groups, and finally
ozonide and carbonyl are formed on the surface for pure epoxy, and epoxy is eroded gradually in depth by ozone. Carbonyl iron
could hinder the meeting of ozone with epoxy with dilution or hindrance effect and could protect epoxy resin from ozone and
thus delay the deterioration of the coating performance. 相似文献
The base catalyst LZ-2, which was the mixture of CaO and Na–NaOH/Al2O3·3H2O, was chosen for the decomposition of phenol tar to generate valuable chemicals. The selectivity of LZ-2 for dimethyl phenyl carbinol, α-methyl styrene dimer and cumenyl phenol was 100%, 100% and 98%, respectively. Under the optimum operating conditions of catalyst 2.5 wt%, operating temperature 603.15 K and decomposition time 3.5 h, decomposition ratios of cumenyl phenol and dimethyl phenyl carbinol were 98.7% and 99.97%, respectively. In addition, the experimental repeatability demonstrated that the total yield of valuable chemicals still reached 90.1% after the catalyst being used five times. Mass and energy balance indicated that the catalytic decomposition was a high potential for the recycling of chemicals from phenol tar. 相似文献
Converting the NO from gaseous pollutant into NH4+ through electrocatalytical reduction using cost-effective materials holds great promise for pollutant purifying and resources recycling. In this work, we developed a highly selective and stable catalyst CoSe2 nanoparticle hybridized with carbon nanotubes (CoSe2@CNTs). The CoSe2@CNTs hybrid catalysts performed an extraordinary high selectivity for NH4+ formation in NO electroreduction with minimal N2O production and H2 evolution. The specific spatial structure of CoSe2 is conductive to the predominant formation of N-H bond between the N from adsorbed NO and H and inhibition of N-N formation from adjacent adsorbed NO. It was also the first time to convert the coordinated NO into NH4+ using non-noble metal catalysis. Moreover, the original concept of employing CoSe2 as eletrocatalyst for NO hydrogenation presented in this work can broaden horizons and provide new dimensions in the design of new highly efficient catalysts for NH4+ synthesis in aqueous solution.
Abstract In light of the practical need for research to inform policy in Beijing, this study evaluates the economic cost of the impact of PM10 pollution in Beijing from 2001 to 2006, taking health as the main impact, and mortality as the main outcome. Based on the literature review, this study adopts relatively conservative parameters as the basis for calculating the health impacts. It concludes that nearly 30% of mortality among registered residents above age 30 in Beijing can be attributed to PM10 pollution, and that the economic cost equals 0.8%–1.2% of the city’s GDP over the same period. This is lower than the results of previous studies, but still high enough to warrant a commitment to solve the city’s air pollution problem. 相似文献
High energy gas fracturing (HEGF) technique has been one of central stimulating measures to enhance oil recovery in low permeability reservoirs. But, in recently few years, some serious CO poisoning accidents took place in oilfields here in China. It is very important to reveal the dynamic mechanisms of carbon monoxide flow and diffusion to operating safety during high energy gas fracturing. In this paper, some dynamic mechanisms of carbon monoxide CO flowing inside a oil wellbore and diffusion on the top of the well during high energy gas fracturing were studied with fluid/gas hydrodynamics. The CO flow model within a wellbore and the diffusion model in air were established. The key factors affecting CO flow and diffusion such as wellbore pressure, gas-oil ratio, wind speed, leakage speed, air-permanence were inspected with mathematical simulation. It will be of significance to provide an important guidance for monitoring and preventing CO poisoning accidents during high energy gas fracturing. 相似文献