208 resultados para contaminantes
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The contamination of the physical environment occurs as a result of the lack of planning and inadequate management of hazardous products. Due to the difficulty of the characterization and study of soil and groundwater, the contamination has been long neglected. The characterization of these areas by research techniques through direct methods such as physical and chemical analysis, are widely used in the diagnosis and monitoring. However, despite presenting quantitative results, this method is not representative in spatial terms. The purpose of this work is to bring geophysical complementation with the diagnosis, bringing the spatial element for the detection of the contamination plume. In the study area, there was a railway accident in 1999 in which three wagons fell and spilled 240,000 L of diesel onto the soil. The main objective is to assess the presence of contaminants in the residual phase and dissolved in the subsurface, using the technique of Electrical Tomography (ETR), understand the effects of natural attenuation process in the degradation of hydrocarbons and changes in electrical properties in soil and groundwater. The results allowed the definition of three distinct patterns of resistivity region with presence of dissolved phase, set in a historical chemical analyzes: low values (> 60Ω.m) associated with the presence of hydrocarbons in an advanced stage of degradation, intermediate values (260Ω.me 511Ω .m) indicative of coexistence of residual hydrocarbons and dissolved phase, and high values (> 1000Ω.m), which reveal the prevalence of residual phase with incipient degradation, possibly in high toxicity concentrations for effective action of biodegradation processes. The diagnostic of areas with potential accumulation of residual phase can subsidize the planning of remediation techniques and promote the complete decontamination of the area
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Persistent Organic Pollutants (POPs) are chemical substances extraordinarily toxic and persistent in the environment. Due to these properties, POPs are targets of the Stockholm Convention which aims to provide means to eliminate production and use by encouraging the reduction and, where possible, eliminating the release of these contaminants to the environment. One of the articles of this _Convention aims to assess the basal levels of such substances in the environment to monitor both the reduction of release to the environment, and to assess human exposure, using analyzes of milk and air for example. Although efforts to control POPs production and release to the environment have been made, data about their levels in Brazil are still scarce, mainly in the atmosphere or indoor environment. Considering the permanence of people inside its house, this study presents a method for POP extraction from XAD-2 sorbent employed in indoor air sampling, with identification and quantification by GC-ECD. GC-ECD linear range of the studied analytes, congeners of polychlorinated biphenyls (PCB) (28, 52, 101, 118, 138, 153 and 180), DDTs and their metabolites (DDDs, DDEs) and endosullan (isomers c - and 13 - and metabolite endosulfan sulfate) ranged between 0.5 and 16.0 ng mL-I with r2 > 0.967. The method developing consist of selecting the extraction solvent system by agitation (90 rpm, 1 hour) with n-hexan,e (2 mL) or n-hexane:acetone (1:1, v/v) (2 mL), concentration the extract with a gentle N2 stream, and evaluation of breakthrough with passage or air through the fortified XAD-2 cartridge before extraction, employing a low volume air suction pump (Pump Model 224 universal-PCXR8; 5-5000 mL min-1, SKC Inc., Eighty Four, PA, USA), Calibrator Dry-Cal DC-Lite (BIOS, Butler, NJ, USA)). Two fortification levels were employed, 15 and 30 ng. After selecting n-hexane as extraction solvent, with accuracy and precision ranging...
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Once petroleum is na exhaustible source of energy, alternative fuels are having more prominence. A much discussed option for replacing fossil fuels is the use of biofuels derived from oils or fats, especially biodiesel. The biodiesel preparation is through a reaction named transesterification, a reaction of triglycerides with a short chain alcohol with a catalyst, producing a mixture of fatty acid esters and glycerol. According to ANP (National Petroleum Agency) specifications, biodiesel can have contaminants due to the catalyst or oil used on its synthesis, such as phosphorus, wich can damage the catalytic converter and cause significant increase in the particles emission. This project aims to develop na alternative method using chemically modified electrodes with iron nanoparticles for determination of phosphorus in biodiesel. For the formation of the iron nanoparticles film on the surface of a glassy carbon electrode, was used a iron sulfate solution. The film was formed after 10 successive cycles, with a scanning speed of 50 mV s-1 and a potential range of -0,9 to -1,25 V. To reduce possible oxides on the surface and activate the electrode, it has been subjected to a cathodic polarization with a potential of -1,25 V for 15 minutes in a sodium hydroxide solution. In cyclic voltammograms obtained in the study of the speed of scanning, there is an increase in the intensity of the anodic and cathodic current peaks. The cathodic peak current varied linearly with the square root of scan rate, showing that the electrode is controlled by diffusion. After successive additions of phosphate there is a linear variation in the current peak in the concentration range of 1,0 x 10-7 a 1,0 x 10-6 mol L-1. To determine if the concentration of phosphorus in real sample, the method of adding standard was used by adding aliquots of phosphate ions in the solution containing soy biodiesel extracted with ....
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Introduction: Several reasons may lead to the failure of polymerase chain reaction (PCR) using DNA purified from paraffin-embedded materials: presence of inhibitors and degradation of target DNA. DNA dilution will often reduce the concentration of potential inhibitors and still contain enough DNA to allow PCR amplification. Objective: To evaluate the dilution influence of DNA purified from paraffin-embedded materials on β-globin PCR amplification. Material and Method: Paraffin-embedded blocks from 30 patients with oropharynx squamous cell carcinomas, diagnosed and treated at the Oral Oncology Center were selected. DNA extraction was performed using QIAmp minikit (Quiagen). DNA was quantified and evaluated for purity by spectrophotometer analysis. Two groups were formed with different amounts of DNA: group I had the originally extracted DNA and group II had the same DNA, however diluted with ultrapure water addition. PCR was performed in both groups using oligonucleotides for human β-globin gene. Results: For Group I, amplification of the β-globin gene sequence was successful in 33.33% of the samples and for Group II, in 23.33%. Conclusion: Dilution of the DNA extracted of paraffin-embedded materials did not modify statistically the amount of positive samples β-globin gene amplified in PCR, although the results suggest that this is a way to increase the method for efficacy amplification of PCR.
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Nas etapas fermentativas destinadas a produção de etanol, observa-se o desenvolvimento de diversos contaminantes, dentre elas as leveduras selvagens, que muitas vezes comprometem a produtividade e qualidade do produto final. Desta forma, o trabalho objetivou caracterizar, classificar e determinar marcadores genéticos-moleculares para 5 estirpes de leveduras (C69, C128, C271, CAT e Saccharomyces cerevisiae). A avaliação envolveu a determinação da assimilação de fonte de carbono e técnica de RAPD (Random Amplified Polymorphic DNA). Os resultados obtidos através dos testes de assimilação de fontes de carbono são importantes para diferenciação e caracterização de leveduras. Sendo, as leveduras C69,C128 e C271 com habilidade para desdobrar xilose como fonte de carbono. A técnica de RAPD obteve dois primers sozinhos não sendo suficientes para a geração de 100 bandas polimórficas para a população, levando-se em conta os resultados do tratamento 2 de 50ng: que pelo polimorfismo gerado pode-se discriminar três grupos principais e distintos: a amostra três sozinha, porém que ocupa uma similaridade com o grupo formado pelo controle e a estirpe 4, e por último o grupo formado pelas amostras 1 e 2, separados do anterior.
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The goal of this work was to develop a strawberry fl avored dairy beverages carbonated and fermented with potential probiotic bacteria. Four formulations of dairy beverages were elaborated: Control (BL); Fermented (BLF); Carbonated (BLC) and Carbonated Fermented (BLFC). In samples submitted for carbonation, a carbonator was used for the carbon dioxide (CO2 ) gas injection dissolved in drinking water and the cultivation consisting of lactic bacteria Lactobacillus acidophilusLA-5®, Bifi dobacterium BB-12® and Streptococcus thermophilus (Biorich, Chr. Hansen) was employed on the fermented samples. The samples were characterized by physical and chemical, microbiological and sensory parameters. The BLC sample showed the presence of yeasts and coliform counts, but the counts indicated that it was suitable for consumption in 28 days time. The BL presented average coliform counts above the limit established by the law after 21 days of refrigerated storage. The presence of lactic bacteria and CO2 and their effects on lower proteolysis indexes, lower pH values and higher acidity values were correlated with signifi cant inhibitory effect of contaminated microorganisms in the BLF and BLFC. The carbonation was not stimulatory for the growth of lactic crops, mainly in the genus Bifi dobacterium spp. and Streptococcus spp. The BLF drink presented greater sensory acceptance and purchase intention test results, however the carbonated beverage presented positive results, with mean values greater than 50% in the acceptance tests with potential inclusion as sensory differential in dairy beverages. Just BLFC drink was considered potentially probiotic, by presenting minimum counts of Lactobacillus spp. during storage. Further studies should be conducted with the technology of carbonation, since it has been proven the correlation of the presence of CO2 with inhibitory effect of contaminated microorganisms and lower physical and chemical changes of dairy beverages.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Pós-graduação em Engenharia Civil e Ambiental - FEB
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Pós-graduação em Microbiologia - IBILCE
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)