In vivo genotoxicity evaluation of a treated urban sewage sludge sample

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Local and cardiorenal effects of periodontitis in nitric oxide-deficient hypertensive rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

iNOS-Derived Nitric Oxide Stimulates Osteoclast Activity and Alveolar Bone Loss in Ligature-Induced Periodontitis in Rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Sewage sludge toxicity in edaphic organism: Analysis of midgut responses in the diplopod Rhinocricus padbergi

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Avaliação em escala laboratorial da utilização do processo eletrolítico no tratamento de águas

Water treatment uses chlorine for disinfection causing formation of trihalomethanes. In this work, an electrolytic water pre-treatment was studied and applied to the water from a fountainhead. The action against microorganisms was evaluated using cast-iron and aluminum electrodes. Assays were made in laboratory using the electrolytic treatment. After 5 min of electrolysis the heterotrophic bacteria count was below 500 cfu/mL and complete elimination of total and fecal coliforms was observed. Using electrolytic treatment as a pretreatment of conventional tap water treatment is proposed.

Photocatalytic Degradation of Phenol by Thermal Titanium Dioxide Thin Layer Electrodes

Electrochemical processes in industrial effluents have been studied as a means to obtain higher efficiency in wastewater treatment. Heterogeneous photocatalysis appears as a low-cost alternative through the use of lower wattage lamps and thermal TiO2 films. Photocatalysis became a clean process for water treatment due to hydroxyl radicals generated on semiconductor surface. Such radicals are able to degrade several organic compounds. This study used different electrodes and analytical methods for degradation of phenol molecules to reduce treatment costs, improve efficiency, and identify compounds formed during the decomposition of phenolic molecules. Thermal growth of TiO2 film was observed on the titanium electrode in rutile form. Application of an electrical potential on the Ti/TiO2 working electrode increases efficiency in reducing concentration of phenol after photocatalytic treatment. Still, high energy radiation (UVC) showed best degradation rates in photolytic process. Different compounds formed during the degradation of phenol were also identified in the UVC-PE treatment.

Método para determinação de distribuição de tamanho de microbolhas (DTMB) em sistemas flotação (FAD) para tratamento de águas utilizando a análise de imagem digital

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Geofungos no Córrego do Sapateiro, Parque Municipal do Ibirapuera, São Paulo, SP, Brasil

No Córrego do Sapateiro, situado no Parque Municipal do Ibirapuera, na cidade de São Paulo, SP, Brasil, amostras de água (50 mL) na profundidade de 10 centímetros foram coletadas em locais antes (local 1) e depois (local 2) da estação de tratamento de flotação, durante os meses da estação chuvosa e quente (janeiro, fevereiro e março) e da estação seca e fria (junho, julho e agosto) de 2008. Além disso, a temperatura, oxigênio dissolvido, condutividade e pH da água foram medidos com um equipamento Horiba U10. Coliformes totais e fecais foram analisados com o kit Aquatest®. A partir de cada amostra de água, alíquotas de 1 mL foram inoculadas em meio batata-dextrose-ágar, totalizando 10 placas de Petri para cada local de coleta. Após incubação por 10 dias a 22 ºC, as colônias fúngicas foram quantificadas, purificadas e identificadas. Os parâmetros abióticos da água não foram limitantes para a presença de geofungos, sendo influenciados pelo tratamento de flotação. Nos dois locais o número de coliformes totais e fecais foi predominantemente superior a 8 NMP dL-1 durante o período estudado. Vinte e sete táxons de fungos foram obtidos, distribuídos em 136 ocorrências. de acordo com o índice de similaridade de Sörensen, a micota dos dois locais coletados foram consideravelmente diferentes, apesar da semelhança entre o número de táxons e ocorrências. Os resultados indicam que o tratamento da água do Córrego do Sapateiro pelo sistema de flotação possivelmente causa modificações na composição taxonômica e na quantidade de UFC de fungos, ao contrário do que ocorreu com os coliformes totais e fecais, cujos resultados apresentaram-se menos conclusivos.

Remoção de substâncias húmicas por meio da oxidação com ozônio e peróxido de hidrogênio e FiME

A filtração em múltiplas etapas (FiME) se apresenta como uma alternativa para realizar o tratamento de água de comunidades de pequeno porte, entretanto, a eficiência quanto à remoção de cor verdadeira associada ao carbono orgânico dissolvido (COD) ou às substâncias húmicas, tem sido questionada ou relatada como baixa. A presente pesquisa avaliou a remoção de substâncias húmicas na FiME com pré-oxidação, com ozônio e peróxido de hidrogênio, utilizando para essa avaliação parâmetros indiretos como cor verdadeira, absorvância UV (254 nm) e COD. Foram realizados cinco ensaios, utilizando quatro filtros lentos, sendo dois com camada de carvão ativado granular (CAG). Foram ensaiadas várias alternativas de pré-oxidação com ozônio e peróxido de hidrogênio. Foram obtidos bons resultados, tendo como principal conclusão que os filtros lentos com CAG, precedidos de oxidação com ozônio e depois peróxido de hidrogênio, apresentaram remoção média de cor verdadeira de 64%, mas que o peróxido de hidrogênio afeta o desenvolvimento da camada biológica, interferindo no desenvolvimento da perda de carga, na remoção de turbidez, na remoção de coliformes e na remoção de substâncias húmicas.

Vascular effects of long-term propranolol administration after chronic nitric oxide blockade

Long-term propranolol treatment reduces arterial blood pressure in hypertensive individuals mainly by reducing peripheral vascular resistance, but mechanisms underlying their vasodilatory effect remain poorly investigated. This study aimed to investigate whether long-term propranolol administration ameliorates the impairment of relaxing responses of aorta and mesenteric artery from rats made hypertensive by chronic nitric oxide (NO) deficiency, and underlying mechanisms mediating this phenomenon. Male Wistar rats were treated with N-omega-Nitro-L-arginine methyl ester (L-NAME; 20 mg/rat/day) for four weeks. DL-Propranolol (30 mg/rat/day) was given concomitantly to L-NAME in the drinking water. Treatment with L-NAME markedly increased blood pressure, an effect largely attenuated by DL-propranolol. In phenylephrine-precontracted aortic rings, the reduction of relaxing responses for acetylcholine (0.001-10 mu M) in L-NAME group was not modified by DL-propranolol, whereas in mesenteric rings the impairment of acetylcholine-induced relaxation by L-NAME was significantly attenuated by DL-propranolol. In mesenteric rings precontracted with KCl (80 MM), DL-propranolol failed to attenuate the impairment of acetylcholine-induced relaxation by L-NAME. The contractile responses to extracellular CaCl2 (1-10 mM) were increased in L-NAME group, and co-treatment with DL-propranolol reduced this response in both preparations in most Ca2+ concentrations used. The NO2/NO3 plasma levels and superoxide dismutase (SOD) activity were reduced in L-NAME-treated rats, both of which were significantly prevented by DL-propranolol. In conclusion, propranolol-induced amplification of the relaxation to acetylcholine in mesenteric arteries from L-NAME-treated rats is sensitive to depolarization. Additional mechanisms involving blockade of Ca2+ entry in the vascular smooth muscle and increase in NO bioavailability contributes to beneficial effects of long-term propranolol treatment. (C) 2007 Elsevier B.V. All rights reserved.

Effect of TiO2 surface modification in Rhodamine B photodegradation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Heterogeneous Fenton reactants: a study of the behavior of iron oxide nanoparticles obtained by the polymeric precursor method

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Protótipos de filtros para água poluida usada para irrigação de hortaliças e frutiferas

Prototypes A (bidin + broken stones + gravel stones + gross sand + activated coal) and B (bidin + broken stones + gravel stones + gross sand) under hydraulic charge of 35 cm presented outlets that, when extrapolated for larger filters, are sufficient to supply small and medium irrigation projects for vegetables and fruits. (bidin = Rhodia polyester for drainage). Under a charge of 35 cm, filtrate of both prototypes presented a reduction of fecal coliforms, being this reduction higher for A prototypes, but, even in this case, the coliform quantities were superior to the legal limit. Under a decrease of the biochemical oxygen demand an increase of the available oxygen rate; pH and hardness did not present significant changes.

Photodegradation of dichloroacetic acid and 2,4-dichlorophenol by ferrioxalate/H2O2 system

The photo-Fenton process using potassium ferrioxalate as a mediator in the photodegradation reaction of organochloride compounds in an aqueous medium was investigated. The influence of parameters such as hydrogen peroxide and ferrioxalate concentrations and initial pH, was evaluated using dichloroacetic acid (DCA) as a model compound under black-light lamp irradiation. An upflow annular photoreactor, operating in a single pass or recirculating mode was used during photodegradation experiments with artificial light. The extent of the release of chloride ions was used to evaluate the photodegradation reaction. The optimum pH range observed was 2.5-2.8. The efficiency of DCA dechlorination increased with increasing concentrations of H2O2 and potassium ferrioxalate, reaching a plateau after the addition of 6 and 1.5 mmol/L of those reagents, respectively. The total organic carbon (TOC) content in DCA and 2,4-dichlorophenol (DCP) solutions was compared with the chloride released after photodegradation. The influence of natural solar light intensity, measured at 365 nm, was evaluated for the dechlorination of DCA on typical summer's days showing a linear dependency. The photodegradation of DCA using black-light lamp and solar irradiation was compared.

Behavior of bromide in the photoelectrocatalytic process and bromine generation using nanoporous titanium dioxide thin-film electrodes

In this study, the photoelectrocatalytic behavior of bromide and generation of bromine using TiO2 was investigated in the separate anode and cathode reaction chambers. Our results show that the generation of bromine begins around a flatband potential of -0.34 V vs. standard calomel electrode (SCE) at pH 3.0 under UV illumination and increases with an increase in positive potential, finally reaching a steady-state concentration at 1.0 V vs. SCE. Maximum bromine formation occurs over the range of pH 4-6, decreasing sharply at conditions where the pH > 7. © 2003 Elsevier Ltd. All rights reserved.