ABSTRACT
The intensive production of polycyclic aromatic hydrocarbons by anthropogenic activities is a serious environmental problem. Therefore, new bioremediation methods are required to avoid widespread contamination. In this work, Serratia sp. AC-11 strain isolated from a tropical peat was selected for immobilization into chitosan beads, which were employed in the biodegradation of fluoranthene. The sizes of the produced beads were relatively uniform with an average diameter of 3 mm. The material was characterized by SEM and FT-IR, confirming the cells immobilization and the protective barrier formed by the chitosan surrounding the biomass. The immobilized bacteria were able to degrade 56% of fluoranthene (the initial concentration was 100 mg L-1) in just 1 day at twice the degradation rate achieved by free-living cells. Furthermore, the immobilized bacteria showed excellent removal during five reuse cycles, from 76% to 59% of biodegradation. These results showed the potential of this approach for remediation of contaminated sites.
Subject(s)
Chitosan/chemistry , Fluorenes/metabolism , Serratia/metabolism , Biodegradation, Environmental , Spectroscopy, Fourier Transform InfraredABSTRACT
In order to further understand the contamination of the citrus pulp pellets (CPP) that were exported to Europe in 1997 we examined both contaminated lime and CPP samples for the distribution of polychlorinated biphenyls (PCBs) and chlorinated benzenes (tri-hexa). Standard isotope dilution techniques were applied for all samples, which were analysed by selected ion monitoring high resolution GC-MS. Lime that is used in the production of CPP product is highly contaminated with PCBs and chlorobenzenes.
Subject(s)
Animal Feed , Calcium Compounds/chemistry , Citrus/chemistry , Environmental Pollutants/analysis , Food Contamination , Oxides/chemistry , Polychlorinated Biphenyls/analysis , Brazil , Commerce , Environmental Monitoring , Europe , Gas Chromatography-Mass SpectrometryABSTRACT
After an exhaustive investigation, in 1997 the source of the milk contamination in Germany was traced to citrus pulp pellets originating from Brazil. It has been shown that lime was the source of the PCDD/F contamination of these products. After this conclusion, a continuous monitoring program has been performed over a two year period and the results are presented in this paper. Standard isotope dilution techniques were used for all samples, which were analyzed by selected ion monitoring high resolution GC-MS.
Subject(s)
Animal Feed , Benzofurans/analysis , Calcium Compounds/chemistry , Citrus/chemistry , Food Contamination , Oxides/chemistry , Polychlorinated Dibenzodioxins/analogs & derivatives , Polychlorinated Dibenzodioxins/analysis , Soil Pollutants/analysis , Animals , Brazil , Commerce , Dibenzofurans, Polychlorinated , Germany , MilkABSTRACT
The authors emphasize the some functional characteristics of the Temporomandibular join, TMJ, and were made comparative study of the auscultatory and sphymografic techniques to TMJ examination. The findings shown that the auscultatory technique furnished important dates to preliminary diagnosis of the TMJ disfunction.
Subject(s)
Temporomandibular Joint Dysfunction Syndrome/diagnosis , Auscultation , Dental Occlusion , Humans , Sound , Temporomandibular Joint Dysfunction Syndrome/physiopathologyABSTRACT
Countless sistemic alterations are broken out by stimuli originated by environmental, nutritional and hormonal conditions that are disadvantageous. In order to verify the effects of these stimuli on the arterial pressure and the urinary excretion of sodium, a group of 100 animals were submitted to illumination for 24 hours, auditive stimulation, dehydration and injection of adrenaline. The results show that constant illumination provokes and increase of arterial pressure (p less than 0.01), that is installed in the first 24 hours and its kept until the end of the experiment. The phasic auditive stimulation encourages an increase of arterial pressure (p less than 0.01) and its consistent to every stimulation. The arterial pressure amount in the introduction of prolonged auditive stimulation (p less than 0.01) but decreases in function of the time of the application of the stimulus. The application of illumination followed by injection of adrenaline, and illumination followed by dehydration not changing the response obtained us an isolated luminous stimulus. The urinary sodium excretion, was increased (p less than 0.01). Based on the results we arrived to the following conclusions: 1) The application of constant illumination and auditive stimulation provoke an increase of arterial pressure; 2) The pressuring responses to the phasic and continuous auditive stimulations are different; 3) There is an increase in the urinary sodium excretion.
