Cancro do colo do útero: que rastreio?

O cancro do colo do útero é um dos cancros evitáveis mais frequente nas mulheres, Ferlay (2004) e Parkin(2005). O padrão epidemiológico da doença, caracterizado por um período longo entre a detecção das primeiras lesões e a instalação da doença, favorece a sua inclusão em programas de rastreio organizado, por serem custo-eficientes e terem ganhos de saúde associados, ver Anttila (2004), Castellsague (2006) e Koutsky (1998). O presente estudo teve como objectivo auxiliar os elementos da Comissão de Rastreio do Cancro do Colo do Útero na Região Norte na tomada de decisões relativas aos aspectos mais controversos dos rastreios ao cancro do colo do útero: limite de idade das mulheres rastreadas, intervalo entre exames e método utilizado. Assim, construiu-se um modelo matemático, com o intuito de simular os impactos económicos e de saúde, das combinações das várias alternativas de rastreio. Por fim, foi feita uma análise custo-benefício das soluções encontradas e determinou-se a solução, i.e. a opção de rastreio, mais vantajosa.Cervical cancer is one of the most frequent avoidable cancers in women, Ferlay (2004) and Parkin(2005). The natural history of the disease, characterized for a long period between the detection of the rst injuries and invasive cancer, favours its inclusion in organized screening programs, since they are cost-e ective and have clear advantages for the health of the population, see Anttila (2004), Castellsague (2006) and Koutsky (1998). The aim of this study is to construct a mathematical model that can help the elements of the Commission delegated for planning the screening program, to decide about the most controversial aspects: target population, interval between examinations and method to be used. The mathematical model allows to simulate the economical and health impact of all the possible solutions. Finally, a cost-bene t analysis of the combined screening alternatives was done to determine the solution, i.e, the more advantageous screening program

Bioremoval of hexavalent chromium by A. viscosus supported on Y and ZSM5 zeolites

Este resumo faz parte de: Book of abstracts of the Meeting of the Institute for Biotechnology and Bioengineering, 2, Braga, Portugal, 2010. A versão completa do livro de atas está disponível em: http://hdl.handle.net/1822/1096

Removal of organic compounds by a biofilm supported on GAC : modelling of batch and column data

The performance of a biofilm of Arthrobacter viscosus supported on granular activated carbon on the retention of organic compounds was evaluated. The presence of functional groups on the cell wall surface of the biomass that may interact with the organic compounds was confirmed by Fourier transform infrared spectroscopy, to assess the applicability of this system to the removal of those compounds. The batch assays showed that the removal percentage decreases with the increasing initial concentration. The removal of phenol ranged from 99.5 to 93.4%, the chlorophenol removal ranged from 99.3 to 61.6% and the o-cresol removal ranged from 98.7 to 73.5%, for initial concentrations between 100 and 1,700 mg/L. The batch data were described by Freundlich, Langmuir, Redlich–Peterson, Dubinin-Radushkevich, Sips and Toth model isotherms and the best fit for the retention of phenol and for the retention of o-cresol was obtained with the Sips model, while for chlorophenol, the best fit was obtained with the Freundlich model. The column tests showed that the retention performance followed the order: phenol > chlorophenol > o-cresol, and increased with the increasing initial organic compound concentration. Data from column runs were described by Adams–Bohart, Wolborska and Yoon and Nelson models with good fitting for all the models.POCTI/FEDER - POCTI/CTA/44449/2002Fundação para a Ciência e a Tecnologia (FCT

Study of Ni (II) and diethylketone removal from aqueous solutions using a biofilm of Streptococcus equisimilis supported on vermiculite

The novelty of this work lies in the development of an environmental-friendly technology to remove diethylketone and Ni (II) from aqueous solutions using the interaction between bacteria and clays. Concentrated biomass of Streptococcus equisimilis and vermiculite were used for the removal of both pollutants No published work on the usage of this combination to remove heavy metals and organic solvents from aqueous solutions was acknowledged. The developed work is original and its impact on society and on environment is evident due to the toxicological effects of those substances on the health of living beings

Zeolites as supports for the biorecovery of hexavalent and trivalent chromium

The aim of this study is the preparation and characterization of new catalytic materials to be used in oxidation reactions through the recovery of heavy metals in wastewater. The recovery of Cr(III) and Cr(VI) from aqueous solutions by an Arthrobacter viscosus biofilm supported on NaY zeolite was investigated. Experiments were repeated without the bacteria for comparison purposes. The batch method has been employed, using solutions with chromium concentrations of 10 mg L-1, 25mgL-1, 50mgL-1 and 100 mg L-1. Cr(III) was easily removed from solution due to its positive charge which allows the entrapment in the framework zeolite by ion exchange. However, due to its anionic form Cr(VI) was only removed in the presence of the biofilm that performs its reduction to Cr(III), followed by ion exchange in the zeolite. The best uptake was achieved for initial concentration of 100 mg L-1: 14mg g-1 zeolite for Cr(III) by both systems and 3 mg g-1 zeolite for Cr(VI) by the zeolite with the bacterium biofilm. The modified zeolite samples have been fully characterized by surface analysis (XRD, XPS), chemical analyses (ICPAES), spectroscopic method (FTIR) and microscopic analysis (SEM). The results show that the biofilm of A. viscosus supported on NaY zeolite is able to recover chromium from dilute solutions and the framework zeolite remains unchanged after chromium biosorption.Fundação para a Ciência e Tecnologia (FCT) - programa POCTI/FEDER (POCTI/44449/ CTA/2002), POCTI-SFA-3-686Universidad de Vigo. Centro de Apoio Científico e Tecnolóxico á Investigación (C.A.C.T.I.

Biosorption of hexavalent chromium by Arthrobacter viscosus

Arthrobacter viscosus biomass was used for Cr(VI) biosorption. The effect of biomass concentration on Cr(VI) reduction and removal from aqueous solution was studied in the range of 1.2 to 5.3 g/L. The removal of Cr(VI) and total chromium increased linearly with the increase of biomass concentration. The best removal efficiencies of Cr(VI) and total chromium were reached for the highest biomass concentration, 72.2 % and 44.0 %, respectively. The increase in biomass concentration did not produce significant changes in the uptake values. The maximum uptake value, 8.2 mgCr/gbiomass, was obtained for a biomass concentration of 2.3 g/L.Fundação para a Ciência e a Tecnologia (FCT

Iron and chromium removal from binary solutions of Fe(III)/Cr(III) and Fe(III)/Cr(VI) by biosorbents supported on zeolites

The goal of the present work is the design of a material that may act as a robust and low cost biosorbent for treatment of wastewater with low concentration of metals ions, such as chromium and iron. The removal of metallic ions from binary aqueous solutions of Fe(III)/Cr(III) and Fe(III)/Cr(VI), by an Arthrobacter viscosus biofilm supported on NaY zeolite was investigated. Experiments were repeated without zeolite for comparison purposes. The batch method has been employed, using for both metals in solution different concentrations (10 mg/L, 25 mg/L and 40 mg/L). The affinity of the transition metals for bacteria in suspension and supported on NaY zeolite, as well as the influence of each competitive ion in the removal mechanism, were evaluated. Results indicated that Arthrobacter viscosus is able to retain the metallic ions, although not totally. The removal efficiencies were improved when the biofilm was added to the zeolite, for all the initial concentrations of Cr(III), for the intermediate and higher concentration of Cr(VI) and for all range of initial concentrations of Fe(III), in the presence of Cr(III). The bacteria reduce Cr(VI) to Cr(III) and, only then, this cation may be entrapped in the framework zeolite by ion exchange [1, 2]. Suspended bacteria had affinity for Fe(III), instead of Cr(VI) and Cr(III), while the conjugated system was selective to Fe(III) just in the case of the presence of Cr(VI). For solutions of Fe(III)/Cr(III), very high removals were achieved in the presence of the supported system, ranging from 94 % to 100 % for Cr(III) and 98 % to 100 % for Fe(III). The conjugated system also allowed reaching the highest removal ratio of Cr(VI), 36 %, for initial concentration of 40 mg/L. The materials in study were characterized by techniques such as FTIR, SEM and XRD

Improved biosorption for Cr(VI) reduction and removal by Arthrobacter viscosus using zeolite

The aim of the present work was to optimize the reduction and removal of chromium from aqueous solutions by a biosorption system consisting of a bacteria supported on a zeolite. The system proposed combines the biosorption properties of Arthrobacter viscosus, with the ion exchange capacity of NaY zeolite. Experiments were also performed without the zeolite for comparison purposes. Experimental parameters such as solution pH, biomass concentration and initial Cr(VI) concentration were investigated in order to assess their influence on the biosorption system. The results revealed that chromium biosorption was highly pH dependent. The lower pH values favored Cr(VI) reduction, while higher solution pH enhanced total chromium removal. After the optimization of the parameters in study, the highest content of chromium in the zeolite (0.9%) and best uptake (13.0 mgCr/gzeolite) were obtained for the experiment at pH 4, biomass concentration of 5 g L−1 and initial Cr(VI) concentration of 100 mg L−1. After the biosorption process, the samples were characterized by chemical analyses (ICP-AES) and X-ray photoelectron spectroscopy (XPS). The XPS spectra of bacteria revealed that the chromium loaded on the biomass surface was in the trivalent form.Dr. C.S. Rodriguez (C.A.C.T.I., Vigo University, Spain) is gratefully acknowledged for performing and interpreting the XPS analyses. Bruna Silva and Hugo Figueiredo thank FCT - Portugal (Fundacao para a Ciencia e Tecnologia) for the concession of their PhD grants. Cristina Quintelas is thankful to the same institution for the concession of a Pos-Doc grant. This work was partially funded by the Centre of Biological Engineering and Centre of Chemistry (University of Minho, Portugal) through an FEDER-COMPETE, FCT project (ref: FCT PEst-C/QUI/UI0686/2011)

Recovery of biotreatment supports as catalysts in ciclohexene oxidation

EUROPACAT IX - Catalysis for a Sustainable WorldA biosorption system for the removal of hexavalent chromium from contaminated effiuents that allows the reutilization of the recovered supports as catalysts is proposed. The system consists of Arthrobacter viscosus bacterium supported on NaY zeolite. After the treatment of the effiuents, the metal-zeolite can be used in oxidation reactions. This work reports the optimized biotreatement conditions that lead to Cr-loaded in Na Y zeolite, which was tested as catalysts in the liquid-phase oxidation of cyclohexene. A comparison is made with a Cr-NaY zeolite prepared by the usual ion-exchange method.info:eu-repo/semantics/publishedVersio