Orientador: Francisco Antonio Bertoz / Coorientador: Maria Cristina Rosifini Alves Rezende / Banca: Marcelo Coelho Goiato / Banca: Kurt Faltin Júnior / Resumo: A ação dos produtos desinfetantes sobre as propriedades físico-químicas da resina acrílica norteia sua seleção para a higienização de aparelhos ortodônticos removíveis. Avaliou-se a resistência à fratura de resina acrílica ativada quimicamente após ciclagem em diferentes soluções desinfetantes. Foram confeccionados quarenta corpos de prova com resina acrílica autopolimerizável incolor (Clássico,Ind.&Com.Ltda./Brasil) utilizando-se matriz metálica retangular e circular, seguindo-se às técnicas de polimerização sob pressão úmida (imersão em água/n=20) e sob pressão seca (sem água/n=20) foram subdivididos em 4 grupos (n=5), conforme a solução utilizada para ciclagem: água destilada (Controle), bicarbonato de sódio, hipoclorito de sódio 1% e Corega®Tabs. A ciclagem consistiu em imersão em 100 ml da solução por 10 minutos três vezes ao dia e, em seguida, manutenção em recipiente fechado contendo saliva artificial a 37ºC. Este ciclo foi realizado durante 30 dias, trocando-se as soluções e a saliva a cada procedimento executado. Na sequência os espécimes foram submetidos ao ensaio de resistência flexural a três pontos foi utilizada máquina EMIC DL3000, à velocidade de 5mm/min, dispondo-se as amostras em suporte contendo dois apoios de sustentação, sendo aplicada força axial e equidistante aos dois outro pontos até a ruptura do corpo-de-prova. Os espécimes circulares foram levados para leitura em Microscópio de Força Atômica (AFM - V Nanoscope Veeco). Os resultados, submetidos à análise de variância (P<0,001 ) e o Teste de Tuckey (P<0,05) não apontaram diferenças significantes para a resistência flexural. Conclui-se que os métodos de polimerização e as soluções testadas não modificaram a resistência flexural... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The disinfectant products action on the physicochemical properties of acrylic resin guides its selection to the cleaning of removable orthodontic appliances. The fracture resistance of acrylic resin after cycling in different disinfectant solutions was evaluated. Forty specimens were made with colorless acrylic resin (Clássico, Ind. & Com.Ltda. / Brazil), using matrix, followed by the techniques of polymerization under wet pressure (immersion in water / n = 20) and dry pressure (no water / n = 20). The samples were divided into 4 groups (n = 5) as the solution used for cycling: distilled water (Control), sodium bicarbonate, sodium hypochlorite 1% and Corega®Tabs. The cycling consisted of immersion in 100 ml of solution for 10 minutes three times a day and then maintained in a closed container containing artificial saliva at 37 º C. These cycles were conducted during 30 days, changing the solutions and artificial saliva for each procedure performed. Latter, the specimens were submitted to surface analysis with Atomic Force Microscope (AFM - Veeco Nanoscope V). A machine, EMIC DL3000, was used for the three-point flexural strength test, speed of 5mm/min, providing the sample in medium containing two restraints support. After that axial force was applied and equidistant to the two other points to the body to break the specimens. The results were submitted to analysis of variace(P<0,001) and Tuckey Test (P<0,05) showed no significant differences in flexural strength test. The Atomic Force Microscopy analysis revealed less topographical roughness for the group Corega®Tabs. We conclude that the polymerization methods and solutions tested did not alter the flexural strength of the material studied except the comparation between... (Complete abstract click electronic access below) / Mestre

Bibliography: leaves 263-270.

Chloramine is a widely used alternative disinfectant for chlorine in potable distribution water. This alternative was investigated and employed to show its effect for suppressing coliforms, trihalomethanes(THMs), disinfection by-products (DBPs), and corrosivity.Coliform analyses were performed with m-Endo(total coliform) and m-T7 agar(injured coliform) by using a standard Membrane Filtration method. Heterotrophic bacteria were monitored with HPC agar(PCA) and R2A agar (nutrient limited agar). EPA methods 502.2, 524.2, and 504 were used to determine levels of Trihalomethanes(THMs) and Disinfection by-products(DBPs).In our study, we observed no significant differences in coliform counts, that could be attributed to the switch in disinfectant. The most common coliform identified was Enterobacter cloacae. We also noted that m-T7 performed better than m-Endo in the detection of coliforms. We also observed a low level of corrosion (0.4-3.8 mils/year) in the distribution system (DS). Higher counts of heterotrophic bacteria were enumerated on R2A when compared to HPC. DBP values decreased two fold when compared with DBP values for the two previous years during which chlorine was used as the disinfectant. / Department of Biology

Thesis (M.S. - Soil, Water and Environmental Sciences)--University of Arizona. / Includes bibliographical references (leaves 107-111)

Thesis (M.S.)--Brigham Young University. Dept. of Microbiology and Molecular Biology, 2007. / Includes bibliographical references (p. 29-31).

Orientador : Jose de Assis Fonseca Faria / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-07-28T05:14:04Z (GMT). No. of bitstreams: 1 Abreu_LauraFigueiredo_M.pdf: 7213340 bytes, checksum: 2f209c5f8a80039c8c4073f52a29fbdf (MD5) Previous issue date: 2001 / Resumo: Através da metodologia de planejamento experimental foram feitas variações de tempo de contato, temperatura e concentração de três diferentes sanificantes para embalagem. Estas variações tiveram como objetivo reduzir de 5 a 6 ciclos logarítmicos a população inicial de esporos de Bacillus subtilis varo globigii(ATCC 9372), no menor espaço de tempo, quando aplicados à superfície interna de garrafas de polietileno tereftalato (PET). Foram testados como agentes sanificantes o peróxido de hidrogênio, o ácido peracético e o álcool etílico, aplicados na forma de spray, através de um sistema de sanificação desenvolvido especialmente para este tipo de teste. O peróxido de hidrogênio e o etanol não apresentaram ação esporicida significativa, sendo adotado como sanificante ideal soluções diluídas de ácido peracético enriquecida com peróxido de hidrogênio. O ácido peracético mostrou ação esporicida entre as concentrações de 0,05% e 1,5%, em um intervalo de temperatura de 30 a 50.C, causando de 1 a 7 reduções decimais. As concentrações de 0,35 a 1,25%, de ácido peracético, não conferiuram sabor estranho à água mineral envasada nas garrafas sanificadas, não diferindo, significativamente (p~O,05),do padrão. O residual de peróxido de hidrogênio das garrafas sanificadas com soluções contendo de 0,05% a 1,5% de ácido peracético, não foi superior a 0,5ppm. Contudo, aquelas sanificadas com soluções contendo 18 e 35% de peróxido de hidrogênio, apresentaram residuais acima de 0,5ppm, chegando a 2ppm. Os dados obtidos forneceram um modelo matemático quadrático, representativo da ação do ácido peracético, em função do tempo e da temperatura, sobre esporos de B. subtilis. Tal modelo, com um R2 de 0,9048, limita-se ao uso de uma concentração máxima de 1,2% de ácido peracético. Garrafas sanificadas com soluções de 0,8% de ácido peracético a 40.C, por 6 segundos e outras com soluções de 0,4% a 36.C por 11 segundos, não apresentaram residual de peróxido maior que 0,2ppm, e não apresentaram crescimento microbiano, quando preenchidas com caldo nutriente e incubadas. O sistema de sanificação testado, utilizandocomo sanificante o ácido peracético, apresentou desempenho satisfatório, podendo ser perfeitamente utilizado por indústrias de pequeno e médio porte na sanificação de garrafas em geral, sendo capaz de promover até 7 reduções decimais na população de esporos bacterianos, por garrafa,coma vantagem do baixocusto do processo / Abstract: The variables: contact time, temperature and concentration were used to study the efficiency of three packing sanitation agents, with the objective to reduce, 5 to 6 logarithmical cycles of Bacillus subtilis varo globigii (ATCC 9372) spores, when applied to the internal surface of the plastic bottles. The hydrogen peroxide, the peracetic acid and the etil alcohol were applied in spray using a sanitation system designed for this study. The hydrogen peroxide and ethanol did not show any significant sporicidal action. The most efficient sanificant agent was the diluted solution of peracetic acid enriched with hydrogen peroxide. Peracetic acid showed sporicidal action in from 0.05 to 1.50% of solution concentration, with a temperature variation of 28 to 50°C, causing from 1 to 7 decimal reductions. From 0.35 to 1.25% concentration of sanificant solution, no off-taste was found, as well as no significant difference from the standard was observed. The hydrogen peroxide residual bottles after sanitation with peracetic acid solution concentration was less than O,50ppm. Nevertheless, the bottles after sanitation with 18 to 35% solution concentration of hydrogen peroxide showed residuais from 0.50 to 2.00ppm. The quadratic model, with R2of 0.9048, is restricted to 1.2% of peracetic acid solution. Neither bottles sanitized with peracetic acid solutions of 0.80% for 6 seconds in a 40°C temperature, or 0.40% at 36°C for 11 seconds, showed peroxide residuais above 0.20ppm, as well as no microbiological growth after filling with nutrient broth and incubated: The sanification system tested, using peracetic acid solution showed satisfactory performance, effective to be used in small and medium industries, with the advantage of cost reductions / Mestrado / Mestre em Tecnologia de Alimentos

The efficacy of six sanitizers, [chloline (200 ppm), iodophor (2S: ppm), acid anionic (200 ppm), peracetic acid (200 ppm), and fatty acid sanitizer (200 ppm)], was evaluated against bacteria attached to gasket materials. Pseudomonas fluorescens, Yersinia enterocolitica, Bacillus cereus, and Listeria monocvtogenes were capable of significant attachment to both buna-N nlbber and Teflon® gasket surfaces in either pure or mixed cultures. Differences in initial attachment rates were evident in a mixed culture of P. fluorescens, Y. enterocolitica, and Listeria monocytogenes in vitro. Sanitizer effectiveness depended upon the bacterium being enumerated, the type of surface, if the bacterium was attached in pure culture or as part of a mixed culture, and the system of evaluation, (i.e. whether or not sanitizer was used alone or as part of a cleaning system). Peracetic acid was the most effective. Removal of bacteria was more pronounced on the Te'f1on® surface with all sanitizers used. The cleaning system, which consisted of a pre-rinse with warm water, application of the cleaning solution, post-rinse with warm water, and application of the sanitizing solution, allowed microorganisms to remain, when the bacteria were present as a pure culture, but resulted in the complete removal of bacteria in mixed culture. / Ph. D.

The objectives of this research were to develop a broad spectrum method for the extraction, concentration, and analysis of drinking water disinfection by products using solid phase extraction (SPE), and to determine if this method had lower detection limits and less variability than the proposed liquid-liquid extraction method, EPA Method 551. The disinfection by products investigated were halogenated nitriles, ketones, and aldehydes. The SPE method extracted and concentrated samples using the C-18 Empore Extraction Disks, and desorbed the analytes with methyl-tert-butyl ether (MTBE) as a solvent. The results showed that with the SPE method the recoveries were low (0-50%) for most compounds, and the limit of detection (LOD) values were in the range of 0.2 to 50 ug/L, which were much higher than those for EPA Method 551. The variability was also higher than for EPA Method 551. The SPE method also appeared to be concentration dependent; the recoveries decreased as analyte concentration increased. Highly saline conditions (250 g/L NaCl) resulted in low recoveries and concentration dependencies for some compounds. Even though the SPE method was easier and faster, the lower method detection limit (MDL) values and lower variability made Method 551 more preferable. Further analysis of the SPE method using a new cyclohexyl disk was also recommended. / Master of Science

Thesis (M. Tech. Environmental health) -- Central University of technology, Free State, 2011 / In nature microorganisms do not exist alone, but in association with one another. These kinds of associations can also be found in food industries, where cells of the same or different species can attach to pipes (biofilm formation) and a variety of surfaces in food processing environments and in food product such as yoghurt which can contain both yeast and bacteria originating from the starter culture as well as fruit. To control food spoilage organisms and food-borne pathogens preventative measures such as good manufacturing processes, the use of sanitizers and preservatives as well as hazard analysis critical control points (HACCP) are crucial in food industries. Sanitation of the working surface, floors, pipes, containers and equipment is a stepwise application of a detergent, acid or alkali rinse, a disinfectant treatment followed by final rinsing. If rinsing of the sanitizer is not done properly it may end up in the product in sub-lethal doses. In this study the influence of Liquid Hypochlorite (LH) and Liquid Iodophore (LI) sanitizers on organism growth and toxicity was evaluated. The organisms investigated included Escherichia coli 0113, Escherichia coli 026 and Zygosaccharomyces bailii Y-1535 in yeast malt broth, which was supplemented with LH and LI at sub-lethal concentrations 0.05% LH, 0.2% LH and 0.075% LI. Subsequently, bacterial and yeast growth responses as pure cultures and in combination (E. coli + Z. bailii) were measured as colony forming units and optical density values. Incorporation of the sanitizers in the growth media resulted in different levels of growth inhibition. Z. bailii proved more robust and the growth rate was not influence significantly by the addition of sanitizers or communal growth with either E. coli strains. The growth rate of both E. coli strains decreased where grown in combination with Z. bailii as well as in the presence of sanitizers, with the most influence exerted by LH. Changes in endotoxicity following the growth of the test samples (stressed cells) and the control (unstressed) were measured by the limulus amoebocyte lysate (LAL) and porcine IL-6 ELISA methods. Where E. coli strains were cultured together with Z. bailii the toxicity of tire mixture showed a decrease over time when measured with the limulus amoebocyte assay method. Interestingly the communal growth of the E. coli strains and Z bailii produced different toxicity profiles when the IL-6 porcine method was used, hi both cases, where E. coli strains were cultured together with Z. bailii the toxicity of the mixture showed an increase over tune when measured by this assay. Other than a similar toxicity profile for E. coli 0113 grown in pure culture, the comparison between results obtained using the LAL or porcine IL-6 methods yielded no correlation in determined toxicity. It was established that LH and LI sanitizers as well as communal growth had an influence in the toxicity of LPS/EPS and the method used to determine such toxicity should be carefully considered.

Thesis (D. Tech. (Biomedical Technology)) -- Central University of Technology, Free State, 2015 / This study reviewed national and international literature to develop an audit-feedback instrument (AFI) to monitor adherence of South African oral health care facilities with compliance to infection prevention and control precautions. In a multi-phased literature search, existing infection prevention and control recommendations, guidelines and audit-feedback instruments were reviewed and broadened to include “dental audit tools”, as well as audit tools from other health care disciplines. Audit-feedback instruments were scrutinised for user friendliness, the use of simple language, electronic calculations and feedback possibilities. A new South African AFI was proposed, considering the differences between public and private oral health care facilities and also the diversity of training levels of oral health care personnel employed. Eleven focus areas supporting all aspects of infection prevention and control in oral health care facilities, including administrative controls; personnel protection controls; environmental- and work controls; surface contamination management; equipment maintenance, service or repair; air- and waterline management; personal protective equipment usage; personal and hand hygiene practices; sterilisation practices; safe sharps handling and waste management were included. The AFI was tested in a sample of 50 oral health care facilities. None of the participating facilities demonstrated 100% compliance. Personal- and hand hygiene practices and waste management performed the best, at respectively 75% and 63%, while administrative controls and air- and waterline management scored the lowest mean values; 31% and 36% respectively The general lack of compliance with infection prevention and control precautions in the participating oral health care facilities clearly poses a safety hazard to both patients and oral health care workers. Results indicate that adherence of South African oral health care facilities with compliance to infection prevention and control precautions need to be improved. The AFI should go a long way towards improving safety and the high expectations about providing quality infection prevention and control outcomes in oral health care.