Spelling suggestions: "subject:"bisphenol A."" "subject:"bisphenols A.""
81 |
Preparation and Characterization of Poly(aryl ether)s Containing Novel Bisphenol Monomers in Flexible SubstrateJuan, Fan-Shuan 07 July 2011 (has links)
In this research that we design in the polymer structure containing the core monomer into benzene ring structure for appied on the flexible substrate and the optoelectronic components .Three novel bisphenol monomers have been synthesised successfully and converted to a series of poly(arylene ether)s by nucleophilic displacement reaction with Bis(4-fluorophenyl) sulfone, then we called them:P1, P2 and P3.We can see from the material structure that the steric hindrance of the group connected to the side of the main chain (M2) is larger than the group in the main chain(M1,M3),and the steric hindrance of the longer length of main chain (M3) is smaller than the shorter one(M1) in the polymerization Thermal analysis physics studies with these polymers confirmed by Thermogravimetric analyzer(TGA) and differential scanning calorimetry (DSC).It is indicated that Td5% of these polymers were 476¢XC~577¢XC in TGA and Tg of these polymers were 264¢XC~290¢XC in DSC. Besides, these polymers were not observed apparent crystallizing point, so we consider that they are not crystallized easily. The transmission spectra of thin film in the visible light region were up to 87%~93%. In drop shape analysis system, the contact angles of them are 85¢X~87¢X, show that they have good hyrophobicity.By above material properties of these polymers, they have high thermal stabilities, high optical transparency and good hydrophobicity.
|
82 |
The Characterization of Genes Involved in Response to the Phenol Derivative and Xenoestrogen Bisphenol-A in Saccharomyces CerevisiaeFarina, Sasha N 01 January 2011 (has links)
Bisphenol A is an estrogenic compound that is found in polycarbonate plastics and epoxy resins; humans are continuously exposed to the compound and it is believed to possess the same carcinogenic effects as estrogen (Iso, 2006). In this study, I used Saccharomyces cerevisiae as a model organism to identify mechanisms by which BPA acts based on the genomic profiling of kinase genes from a Mat-α haploid deletion library. Kinases regulate many other proteins, so the identification of a single mutant could identify an entire affected pathway of genes. I conducted a systematic screen of these mutants using the phenotype of growth inhibition. Using solid growth assays, I identified 17 BPA sensitive mutants, six of which were related to the high osmolarity growth pathway, which is involved in osmotic stress response and could be a mechanism of defense of S. cerevisiae against BPA. I implemented liquid growth assays, protein analysis, as well as microscopy for a more in depth study of the effects of BPA on these mutants. Bisphenol-A initially inhibits the growth of S. cerevisiae, however, there were some strains that appeared to show adaptation in the presence of the compound. I found that BPA inhibits cell cycle progression, and may affect the phosphorylation regulation of Cdc28, but without affecting the production of the protein. This study provides clues for predicting the effects of BPA on homologous genes in mammals and identifying similar pathways of resistance. By having a better understanding of the effects on BPA on the cell, the compound can be better regulated by the EPA and complications resulting from continuous exposure to BPA can be treated effectively.
|
83 |
Human health implications of exposure to xenoestrogens from foodThomson, Barbara Mary January 2005 (has links)
This thesis aims to assess the human health impact of exposure to estrogenic compounds from the diet. A multi-disciplinary approach is taken to address various aspects of this issue. An introduction to xenoestrogens, including international research priorities, wildlife and human health effects, mechanisms of action, structure activity relationships and additivity of estrogenic effects is provided as background information. An assessment of exposure to a range of naturally occurring and synthetic estrogenic compounds found in food is derived in Chapter 2. The assessment combines new and existing data on food concentration, food consumption and serum levels for each xenoestrogen. Exposure is combined with relative estrogenic potency data from published bioassasy data to estimate risk relative to normal circulating levels of estradiol. Assuming additivity of xenoestrogens, for an average New Zealand male and for post-menopausal women, xenoestrogens in the diet contribute an additional 12-90% of estrogenicity above normal circulating levels. For a pre-menopausal female, the contribution from the diet represents in the order of an additional 2%. The level of exposure determined in this thesis would seem to be of pharmacological relevance, especially for men with low levels of estrogen and for post-menopausal women. Bisphenol A (BPA) is an important monomer used in the manufacture of epoxy resins for internal food can linings. A survey of the BPA content of a range of 80 canned foods available to the New Zealand consumer was undertaken and the results used in the exposure and risk assessments. BPA was detected in all foods analysed except soft drinks, at concentrations ranging from <10-29 µg/kg, except for individual samples of tuna, corned beef and coconut cream that were 109, 98 and 191 µg/kg respectively. None, of over 4000 individual exposure scenarios, exceeded the temporary Tolerable Daily Intake (TDI) of 10 µg/kg body weight per day set by the Scientific Committee on Food in 2002. Intestinal microflora influence the bioavailability of the naturally occurring xenoestrogens genistein and daidzein that contribute significantly to total estrogenicity from the diet. The degradation of genistein and daidzein by the faecal microfloral of 5 human subjects was variable and unpredictable between individuals and within an individual. These findings have important implications for the promotion and prescription of soy foods and supplements for disease prevention and health benefits. The "yeast assay" is one of a number of methods available to measure estrogenicity. This assay was established and validated. In utero exposure to estrogenic compounds at critical periods of sexual differentiation and endocrine development may imprint for health effects observed later in life. Placental transfer of estrogenicity, from 17β-estradiol was studied using the human placental perfusion model and the yeast assay. The placenta provides a protective barrier to the transfer of estrogenicity. Experiments with genistein showed that 5-15% placental transfer occurred, suggesting that in utero exposure might be in the order of 10% of maternal exposure. The thesis concludes with consideration of a genomic approach to substantiate, or refute, the mechanistic link between exposure to xenoestrogens and claimed human health effect. Such an approach offers exciting opportunity to clarify the mode of action of the synthetic versus the naturally occurring xenoestrogens, to confirm or dispute additivity of effect that is an important premise of the exposure assessment, to identify key genes involved in the many possible health effects and thence risk to the individual from dietary exposure to xenoestrogens.
|
84 |
Remo??o de bisfenol-A por silicatos modificados com cobaltoCruz, Alenice Ferreira 05 October 2016 (has links)
Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2017-03-23T19:40:24Z
No. of bitstreams: 2
license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)
alenice_ferreira_cruz.pdf: 3398178 bytes, checksum: 4f7c2c8ff0a3c9856be63b637e43306b (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2017-04-20T16:59:10Z (GMT) No. of bitstreams: 2
license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)
alenice_ferreira_cruz.pdf: 3398178 bytes, checksum: 4f7c2c8ff0a3c9856be63b637e43306b (MD5) / Made available in DSpace on 2017-04-20T16:59:11Z (GMT). No. of bitstreams: 2
license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)
alenice_ferreira_cruz.pdf: 3398178 bytes, checksum: 4f7c2c8ff0a3c9856be63b637e43306b (MD5)
Previous issue date: 2016 / O bisfenol-A ? um importante produto qu?mico, amplamente utilizado em ind?strias para a
produ??o de policarbonatos, resinas epoxi e outros pl?sticos. Existe uma car?ncia em
desenvolver m?todos eficazes para remov?-lo de efluentes. Uma vez que, o mesmo faz parte
dos chamados poluentes emergentes, pois ? um contaminante prejudicial para os organismos,
mesmo em baixas concentra??es, devido ao seu efeito nocivo sobre sa?de. Neste trabalho,
buscou-se avaliar o desempenho de dois silicatos mesoporosos (MCM-41 e Co-silicato) frente
? adsor??o do bisfenol-A. Os perfis de difra??o de raio-X dos materiais confirmaram a
forma??o da MCM-41 e o material modificado (Co-silicato) demonstrou alterar ao ?nico
elemento de ordem estrutural, que ? a disposi??o dos canais paralelos (2?=2). As imagens de
MEV mostraram que os materiais n?o apresentaram morfologia definida. Dados indicaram
que ambos os materiais apresentam elevada ?rea espec?fica, sendo 988 m2g-1 para MCM-41 e
729 m2g-1 para Co-silicato. O material Co-silicato mostrou elevado potencial como
adsorvente, frente ? MCM-41. A elevada ?rea superficial, aliada ao tamanho dos poros,
juntamente com a presen?a de ?ons met?licos (cobalto) favoreceram o processo de adsor??o.
A forma??o de s?tios ativos no silicato, ap?s a inser??o de cobalto, favoreceu a adsor??o do
contaminante. A partir dos testes de adsor??o realizados em pH 3, 6 e 9 foi poss?vel notar que
o material que teve uma melhor capacidade de adsor??o foi o material Co-silicato. Diante dos
testes de cin?tica, o material Co-silicato nas faixas de pH analisadas demonstrou maior
potencial de adsor??o do bisfenol-A, em rela??o ao resultados de remo??o obtidos com o
material MCM-41. Os modelos utilizados para os ajustes matem?ticos da adsor??o foram as
isotermas de Langmuir, Freundlich, e Redlich-Peterson. O valor do coeficiente de correla??o
(R2) 0,9641 pH 3; (R2) 0,9834 pH 6 e (R2) 0,9959 pH 9 dos par?metros de Redlich-Peterson
sugeriram que o modelo de Redlich-Peterson descreve melhor o comportamento de adsor??o
de bisfenol-A no material Co-silicato, j? que apresenta maior valor do coeficiente de
correla??o em pH testados, comparando com os valores de correla??o (R2) de Langmuir e
Freundlich. Os dados revelaram que a modifica??o da MCM-41 com ?tomos de cobalto
alteraram as propriedades f?sico-qu?mica do material, e potencializou o adsorvente para
adsor??o da mol?cula de bisfenol-A. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Qu?mica, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2016. / Bisphenol-A is an important chemical, widely used in industries for the production of
polycarbonates, epoxy resins and other plastics. There is a lack of effective methods to
remove it from effluents. Since it is part of so-called emerging pollutants, it is a harmful
contaminant for organisms, even in low concentrations, because of its harmful effect on
health. This work aimed to evaluate the performance of two mesoporous silicates (MCM-41
and Co-silicate) against the adsorption of bisphenol-A. The X-ray diffraction profiles of the
materials confirmed the formation of MCM-41 and the modified material (Co-silicate) was
shown to change to the only structural element, which is the arrangement of the parallel
channels (2? = 2). The SEM images showed that the materials did not present definite
morphology. Data indicated that both materials presented a high specific area, being 988 m2g-
1 for MCM-41 and 729 m2g-1 for Co-silicate. Co-silicate material showed high adsorbent
potential compared to MCM-41. The high surface area, together with the pore size, together
with the presence of metallic ions (cobalt) favored the adsorption process. The formation of
active sites in the silicate, after the insertion of cobalt, favored the adsorption of the
contaminant. From the adsorption tests carried out at pH 3, 6 and 9 it was possible to observe
that the material with the best adsorption capacity was the Co-silicate material. Due to the
kinetic tests, the Co-silicate material in the analyzed pH ranges showed a higher adsorption
potential of bisphenol-A in relation to the removal results obtained with the MCM-41
material. The models used for the mathematical adjustments of the adsorption were the
isotherms of Langmuir, Freundlich, and Redlich-Peterson. The value of the correlation
coefficient (R2) 0.9641 pH 3; (R2) 0.9834 pH 6 and (R2) 0.9959 pH 9 of the Redlich-Peterson
parameters suggested that the Redlich-Peterson model better describes the adsorption
behavior of bisphenol-A in the Co-silicate material, since it presents Higher value of the pH
correlation coefficient tested, compared with the Langmuir and Freundlich correlation values
(R2). The data revealed that the modification of MCM-41 with cobalt atoms altered the
physicochemical properties of the material and potentiated the adsorbent for adsorption of the
bisphenol-A molecule.
|
85 |
Vliv endokrinních disruptorů na funkčnost spermií a změny ve steroidogenezi transkriptomik u rybHATEF, Azadeh January 2012 (has links)
In the present study, both in vitro and in vivo experiments were performed to investigate modes of action of selected EDCs including mercury chloride (HgCl2), bisphenol A (BPA), vinclozolin (VZ) and Di-(2-ethylhexyl)-phthalate (DEHP) on male reproductive physiology in fish. Results obtained from in vitro studies showed that EDCs decrease sperm motility via disruption in energetics and damage to spermatozoa; however the effective doses are higher than reported in the environmentally relevant concentrations. In contrast, in vivo studies showed adverse effects of BPA, VZ, and DEHP on sperm quality at environmentally relevant concentrations. Decrease in sperm quality is associated with disruption in testicular steroidogenesis, particularly inhibition of androgens. Only BPA induced vitellogenin production, associated with increase in transcripts of estrogen receptor, androgen receptor and cytochrome P450 mRNA at the high dose approaching environmental level. Inhibition of androgen production is due to disruption in transfer of cholesterol into the steroidogenesis pathway, because transcript of steroidogenic acute regulatory protein mRNA was decreased. In addition, BPA acts through sex steroid-mediated mechanism while DEHP mode of action is sex-steroid independent mechanism.
|
86 |
Degradação simultânea de bisfenol A e carbamazepina em efluente de estação de tratamento de esgoto por processo foto-Fenton / Simultaneous degradation of bisphenol A and carbamazepine in effluent from sewage treatment plant using photo-Fenton processAlamino, Andreza de França [UNESP] 19 August 2016 (has links)
Submitted by Andreza de França Alamino null (andreza.alamino@hotmail.com) on 2016-09-10T18:02:45Z
No. of bitstreams: 1
dissertacao_versão_final_pdf_repositório_unesp.pdf: 1884907 bytes, checksum: 6161a04cdaac1c53204da25be3831d76 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-09-13T14:20:36Z (GMT) No. of bitstreams: 1
alamino_af_me_araiq.pdf: 1884907 bytes, checksum: 6161a04cdaac1c53204da25be3831d76 (MD5) / Made available in DSpace on 2016-09-13T14:20:36Z (GMT). No. of bitstreams: 1
alamino_af_me_araiq.pdf: 1884907 bytes, checksum: 6161a04cdaac1c53204da25be3831d76 (MD5)
Previous issue date: 2016-08-19 / O presente trabalho aborda a degradação simultânea de dois contaminantes emergentes, o plastificante bisfenol A (BPA) e o fármaco carbamazepina (CBZ), aplicando-se processos oxidativos avançados (POA), particularmente o processo foto-Fenton. Durante os ensaios de degradação, o BPA e a CBZ foram determinados por cromatografia líquida de alta eficiência (CLAE) em uma única análise, utilizando dois detectores acoplados em série, o detector de fluorescência (FLU) para o BPA e detector de arranjo de diodos (DAD) para a CBZ. Foi necessária a otimização das condições do método cromatográfico, tais como, composição da fase móvel, 50% etanol-água, vazão, 0,500 mL min-1, comprimento de onda de excitação e emissão para o BPA, 277 e 300 nm nesta ordem, e absorção para a CBZ de 286 nm ou 211 nm. Após a construção da curva analítica foram determinados os parâmetros analíticos como: linearidade, limites de detecção e quantificação. Os ensaios de degradação foram efetuados em duas matrizes distintas, água e efluente de estação de tratamento de esgoto, coletado antes do lançamento nos rios, objetivando desenvolver um método de degradação em baixas concentrações em amostras reais. Pela complexidade da matriz foi necessário fazer o “clean up” das amostras por extração em fase sólida (EFS) nas alíquotas retiradas durante as degradações no efluente. A faixa de recuperação da EFS foi avaliada em três níveis e atingiu de 82 a 84% para o BPA e de 92 a 99% para a CBZ. A velocidade de degradação tanto de BPA como de CBZ foi influenciada pela matriz, pois foi maior em água do que no efluente. O tempo de degradação em água foi de 60 minutos e em efluente de 90 minutos. A degradação de BPA atingiu 88% em água e 77% em efluente, enquanto que de CBZ atingiu 95% em água e 61% em efluente. A remoção de carbono orgânico dissolvido (COD) nas amostras de efluente foi avaliada, porém as concentrações de Fe(III) e H2O2 utilizadas, 12,0 μmol L-1 e 300 μmol L-1 nesta ordem, não foram suficientes para degradar a matéria orgânica do efluente, mas foram suficientes para a degradação dos compostos alvos na concentração de 250 μg L-1.
|
87 |
Remoção de bisfenol A de águas contaminadas através de processos de separação por membranas e de sorçãoDal Magro, Renata January 2013 (has links)
Os desreguladores endócrinos, como o bisfenol A (BPA), são compostos encontrados na água em concentrações da ordem de μg.L-1 ou ng.L-1, sendo por isso também denominados micropoluentes. Sua presença, mesmo em baixas concentrações, pode causar prejuízos aos organismos expostos. Neste contexto, o objetivo do presente trabalho foi avaliar a remoção de BPA por membranas de ultrafiltração (UF) e osmose inversa (OI) e por carvão ativado granular (CAG). Essas técnicas têm a vantagem de não gerar subprodutos que também podem ser tóxicos. Nos estudos foram realizados experimentos para remoção do BPA através de membrana PL-1 (celulose regenerada de 1 kDa), Sy-10 (polietersulfona de 10 kDa) e membrana de OI (poliamida) reutilizada, com concentração inicial de 500 μg.L-1 de BPA. Para a membrana Sy-10, foram testados os pHs 7 e 10. Os ensaios de adsorção foram realizados com CAG (1-2mm) em frascos contendo 100 mL da solução de BPA, com 0,5 g de CAG para cada frasco. As variáveis testadas foram pH, tempo de contato e concentração inicial na ordem de mg.L-1. Adicionalmente, foi testada a concentração inicial de 500 μg.L-1 de BPA em experimento de adsorção. Os resultados obtidos mostraram que a capacidade da membrana Sy-10 para remoção de BPA foi superior, chegando a cerca de 90% de remoção, em contraposição aos 20% encontrados para PL-1. A membrana de OI apresentou remoções de cerca de 95%. A influência do pH (7 e 10) na remoção do BPA para a membrana Sy-10 não mostrou-se significativa. Nos ensaios de adsorção, analisando diferentes valores de pH, obteve-se eficiência de 93% para pH 7. Ensaios de variação do tempo de contato com CAG mostraram que o equilíbrio é atingido nos primeiros 10 minutos para a maior concentração e em 40 minutos para a menor concentração testada, de 500 μg.L-1. O estudo do efeito da concentração inicial de BPA na adsorção mostrou que a remoção aumenta com o aumento da concentração inicial do poluente. Conclui-se que tanto a adsorção em CAG quanto membranas são boas alternativas para a remoção de BPA de soluções aquosas. As duas técnicas poderiam ser usadas conjuntamente, sendo que o concentrado do processo com membranas poderia ser submetido à adsorção por CAG. / Endocrine disrupting chemicals, such as bisphenol A (BPA) compounds, are found in water at concentrations of the order of μg.L-1 or ng.L-1 is therefore also known micropollutants. His presence, even at low concentrations, can cause damage to exposed organisms. In this context, the aim of this study was to evaluate the removal of BPA by ultrafiltration (UF) and reverse osmosis (RO) membranes and granular activated carbon (GAC). These techniques have the advantage of not generating by-products can also be toxic. In the studies were performed experiments to remove the BPA by PL-1 (1 kDa regenerated cellulose), Sy-10 (10 kDa polyethersulfone) and RO (polyamide) reused membranes, with initial concentration of 500 μg.L-1 of BPA. For Sy-10 membrane pHs 7 and 10 were tested. The adsorption experiments were carried out with GAC (1-2mm) in flasks containing 100 mL of the BPA solution and 0.5 g of GAC to each vial. The variables tested were pH, contact time and initial concentration on the order of mg.L-1. Additionally, we tested the initial concentration of 500 μg.L-1 of BPA in adsorption experiment. Results showed that the capacity of Sy-10 membrane to remove BPA was higher, reaching approximately 90% removal, as opposed to the 20% found to PL-1. The RO membrane showed removal of about 95%. The influence of pH (7 and 10 ) in the removal of BPA onto the membrane Sy - 10 was not significant. In adsorption tests, analyzing different pH values was obtained efficiency from 93% to pH 7. Testing time variation of contact GAC showed that equilibrium is reached in the first 10 minutes to the largest concentration and 40 minutes to the lowest concentration tested, 500 μg.L-1. The study of the effect of the initial concentration of BPA in the adsorption showed that removal increases with increase in the initial concentration of the pollutant. It was concluded that both the GAC adsorption as membranes are good alternatives for the removal of the BPA aqueous solutions. The two techniques could be used together, with the concentrate from the membrane process could be subjected to adsorption GAC.
|
88 |
Remoção de bisfenol A de águas contaminadas através de processos de separação por membranas e de sorçãoDal Magro, Renata January 2013 (has links)
Os desreguladores endócrinos, como o bisfenol A (BPA), são compostos encontrados na água em concentrações da ordem de μg.L-1 ou ng.L-1, sendo por isso também denominados micropoluentes. Sua presença, mesmo em baixas concentrações, pode causar prejuízos aos organismos expostos. Neste contexto, o objetivo do presente trabalho foi avaliar a remoção de BPA por membranas de ultrafiltração (UF) e osmose inversa (OI) e por carvão ativado granular (CAG). Essas técnicas têm a vantagem de não gerar subprodutos que também podem ser tóxicos. Nos estudos foram realizados experimentos para remoção do BPA através de membrana PL-1 (celulose regenerada de 1 kDa), Sy-10 (polietersulfona de 10 kDa) e membrana de OI (poliamida) reutilizada, com concentração inicial de 500 μg.L-1 de BPA. Para a membrana Sy-10, foram testados os pHs 7 e 10. Os ensaios de adsorção foram realizados com CAG (1-2mm) em frascos contendo 100 mL da solução de BPA, com 0,5 g de CAG para cada frasco. As variáveis testadas foram pH, tempo de contato e concentração inicial na ordem de mg.L-1. Adicionalmente, foi testada a concentração inicial de 500 μg.L-1 de BPA em experimento de adsorção. Os resultados obtidos mostraram que a capacidade da membrana Sy-10 para remoção de BPA foi superior, chegando a cerca de 90% de remoção, em contraposição aos 20% encontrados para PL-1. A membrana de OI apresentou remoções de cerca de 95%. A influência do pH (7 e 10) na remoção do BPA para a membrana Sy-10 não mostrou-se significativa. Nos ensaios de adsorção, analisando diferentes valores de pH, obteve-se eficiência de 93% para pH 7. Ensaios de variação do tempo de contato com CAG mostraram que o equilíbrio é atingido nos primeiros 10 minutos para a maior concentração e em 40 minutos para a menor concentração testada, de 500 μg.L-1. O estudo do efeito da concentração inicial de BPA na adsorção mostrou que a remoção aumenta com o aumento da concentração inicial do poluente. Conclui-se que tanto a adsorção em CAG quanto membranas são boas alternativas para a remoção de BPA de soluções aquosas. As duas técnicas poderiam ser usadas conjuntamente, sendo que o concentrado do processo com membranas poderia ser submetido à adsorção por CAG. / Endocrine disrupting chemicals, such as bisphenol A (BPA) compounds, are found in water at concentrations of the order of μg.L-1 or ng.L-1 is therefore also known micropollutants. His presence, even at low concentrations, can cause damage to exposed organisms. In this context, the aim of this study was to evaluate the removal of BPA by ultrafiltration (UF) and reverse osmosis (RO) membranes and granular activated carbon (GAC). These techniques have the advantage of not generating by-products can also be toxic. In the studies were performed experiments to remove the BPA by PL-1 (1 kDa regenerated cellulose), Sy-10 (10 kDa polyethersulfone) and RO (polyamide) reused membranes, with initial concentration of 500 μg.L-1 of BPA. For Sy-10 membrane pHs 7 and 10 were tested. The adsorption experiments were carried out with GAC (1-2mm) in flasks containing 100 mL of the BPA solution and 0.5 g of GAC to each vial. The variables tested were pH, contact time and initial concentration on the order of mg.L-1. Additionally, we tested the initial concentration of 500 μg.L-1 of BPA in adsorption experiment. Results showed that the capacity of Sy-10 membrane to remove BPA was higher, reaching approximately 90% removal, as opposed to the 20% found to PL-1. The RO membrane showed removal of about 95%. The influence of pH (7 and 10 ) in the removal of BPA onto the membrane Sy - 10 was not significant. In adsorption tests, analyzing different pH values was obtained efficiency from 93% to pH 7. Testing time variation of contact GAC showed that equilibrium is reached in the first 10 minutes to the largest concentration and 40 minutes to the lowest concentration tested, 500 μg.L-1. The study of the effect of the initial concentration of BPA in the adsorption showed that removal increases with increase in the initial concentration of the pollutant. It was concluded that both the GAC adsorption as membranes are good alternatives for the removal of the BPA aqueous solutions. The two techniques could be used together, with the concentrate from the membrane process could be subjected to adsorption GAC.
|
89 |
Efeito do tipo de revestimento estetico e da eletroerosão sobre a desadaptação de infra-estruturas metalicas implantossuportadas / Influence of vennering material and spark erosion on marginal misfit of implant-suported frameworksOliveira, Luciana Valadares 26 June 2007 (has links)
Orientador: Marcelo Ferraz Mesquita / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-09T19:25:40Z (GMT). No. of bitstreams: 1
Oliveira_LucianaValadares_D.pdf: 36824583 bytes, checksum: 7a4d2a0d063c3cd9180327ea1a830f60 (MD5)
Previous issue date: 2007 / Resumo: As distorções oriundas das técnicas de aplicação dos revestimentos estéticos sobre infraestruturas metálicas de próteses fixas podem resultar em margens cervicais desadaptadas. Este trabalho avaliou o efeito do tipo de revestimento estético, da simulação dos ciclos de cocção da porcelana e da eletroerosão sobre o desajuste de infra-estruturas implantossuportadas. Foi utilizada uma matriz metálica simulando um arco mandibular, contendo 5 pilares intermediários do tipo Microunit (Conexão Sistema de Próteses, Brasil). Sobre essa matriz, foram enceradas 40 infra-estruturas, fundidas em liga de CoCr (Remanium 2000, Alemanha). Para cada infra-estrutura, foi confeccionado um index, parafusando-se 5 réplicas em cada uma das infra-estruturas. Esse conjunto foi posicionado em gesso pedra especial com auxílio de delineador, antes da aplicação dos revestimentos estéticos, para avaliar o desajuste provocado apenas pela fase de aplicação dos revestimentos estéticos e ciclo de cocção da porcelana. As infra-estruturas foram separadas aleatoriamente: G1: resina acrílica termopolimerizável (Clássico, Clássico, Brasil); G2: resina fotopolimerizável (Versyo.com, Heraeus Kulzer, Brasil); G3: porcelana (Carmen, Dentaurum, Alemanha); G4: simulação dos ciclos de cocção da porcelana. Antes da aplicação dos revestimentos estéticos, foi realizada a avaliação do desajuste marginal sobre o index, após aperto de 10 Ncm em um único parafuso, correspondente ao implante A. Através desse procedimento, verificou-se a adaptação dos componentes C e E. O procedimento foi repetido no outro implante mais distal (E), para mensuração nos implantes A e C. As leituras foram realizadas utilizando microscópio mensurador (STN ¿ Olympus Optical, Japão). Procedeu-se o processo de eletroerosão (Tel Med Technologies, EUA), e novamente avaliação do desajuste marginal. Os resultados obtidos foram submetidos à Análise de Variância e teste de Tukey (p<0,05). Os valores de desajuste marginal das infra-estruturas antes da aplicação dos revestimentos estéticos não apresentaram diferença estatística significante entre si: G1: 56,97 µm (± 16,86); G2: 43,27 µm (± 16,49); G3: 49,26 µm (± 17,11); G4: 40,66 µm (+ 10,85). A aplicação dos revestimentos estéticos e simulação dos ciclos de cocção da porcelana aumentaram significantemente os valores médios de desajuste marginal para todos os grupos: G1: 170,01 µm (±53,98); G2: 72,32 µm (±27,49); G3: 164,84 µm (±27,67); e G4: 86,28 µm (±20,01). Os grupos G1 e G3 não apresentaram diferença estatisticamente significante entre si, mas apresentaram diferença quando comparados aos G2 e G4. Após eletroerosão, as médias de desajuste marginal apresentaram valores significamente menores para os grupos: Gl: 108, 54 µm (±40,75); G3: 109,61 µm (±24,42); e G4: 59,63 µm (±22,13). A média de desajuste marginal para o grupo de resina fotopolimerizável não apresentou diferença estatística significante: G2: 49,70 µm (±16,65). Como observado anteriormente, os grupos G1 e G3 não apresentaram diferença estatística significante, mas ambos apresentaram diferença dos grupos G2 e G4. Conclui-se que os revestimentos estéticos em resina acrílica e porcelana produzem os maiores valores de desajuste marginal para próteses implantossuportadas, enquanto a resina fotopolimerizável, os menores. A aplicação de porcelana resultou em maiores valores de desajuste marginal que apenas a simulação dos ciclos de cocção. A eletroerosão foi eficaz na redução dos desajustes marginais até os limites considerados clinicamente aceitáveis / Abstract: The demand for a passive fit of frameworks for osseointegrated endousseous implants abutments is well known, because the tightening of an inaccurate framework to the abutments can transmit stress to the bone-metal interface. The purpose of the present study was to evaluate the influence of the veneering application and porcelain firing cycle on the misfit level of implant-supported frameworks. Forty Co-Cr (Remanium 2000, Dentaurum, Germany) alloy frameworks were fabricated from a metallic index containing 5 Branemark type multi unit abutments. Analogs of the abutments were positioned to the framework, to construct an index for each framework. This index allowed the observation of the marginal gaps caused by the application of the veneering material. The frameworks were grouped (n=10): 1) heat acrylic resin (Clássico, Clássico, São Paulo, Brazil); 2) light polymerized resin (Versyo.com, Heraeus Kulzer, Brazil); 3) porcelain application (Carmen, Dentaurum, Germany); 4) simulation of porcelain firing cycle. Marginal refinement with spark erosion was conducted on specific equipment (Tel Med Technologies, U.S.A.). The marginal gap was obtained before and after the veneering materials and the spark erosion procedure, following the single screw test protocol (using a tightening force of 10 Ncm). A traveling microscope (STN ¿ Olympus Optical Co. Ltd Japan (120X) was used, tightening 10N in the titanium screw of the extremity distal implant, measuring the gaps at the central and distal implants. Data were subject Analysis of Variance followed by Tukey test (5%). Marginal gap mean values of the frameworks before the veneering application were not significantly different: G1: 56.97(± 16.86); G2: 43.27(± 16.49); G3: 49.26(± 17.11); G4: 40.66(± 10.85). The application veneering materials and the simulation of porcelain firing cycle increased significantly the misfit mean values of all groups: G1: 170.01 µm (±53.98); G2: 72.32 µm (+±27.49); G3: 164.84 µm (±27.67); e G4: 86.28 µm (±20.01). There were no significant differences between G1 and G3, but they were significantly different from both G2 and G3. After the spark erosion process, marginal gap mean values decreased significantly for the following groups: G1: 108. 54 µm (±40.75); G3: 109.61 µm (±24.42); and G4: 59.63 µm (±22.13). The light curing group decreased the marginal gap mean values, but not significantly after the spark erosion procedure: G2: 49.70 µm (±16.65). As occurred after the application of veneering materials, G1 and G3 groups did not show significant difference, but they both were significantly different from G2 and G4 groups. It can be concluded that heat cured acrylic resin and porcelain produced the highest mean values of marginal gaps, while light cured acrylic resin, the lowest. The application of porcelain produced higher misfit values than the simulation of porcelain firing cycles only. The spark erosion procedure was efficacious in reducing the frameworks marginal gaps to the levels clinically accepted for all groups evaluated. / Doutorado / Protese Dental / Doutor em Clínica Odontológica
|
90 |
Can We Re-use “Single-Use” Solid Phase Extraction Cartridges?Morrison, Erin R. 02 November 2017 (has links)
Organic and inorganic compounds are present as contaminants in varying concentrations throughout our water cycle. Examples of these contaminants include the endocrine disrupting compounds (EDCs) bisphenol-A (BPA) and 17β-estradiol (E2) from plastics and pharmaceutical use. It can be necessary to obtain the concentration of these compounds within the water cycle for analysis by interested parties such as research groups, regulatory agencies, and private organizations. These concentrations, however, can be too dilute within the initial sample for analysis. Therefore it is necessary to concentrate the compound of interest (analyte) prior to analysis. One such way to do this is by way of Solid Phase Extraction (SPE).
SPE uses a small cartridge which contains chromatographic packing material to chemically extract analytes from a water sample onto a solid phase. To increase concentration, these analytes are then transferred (eluted) to a substantially smaller volume of organic solvent for eventual analyses. These commercially available cartridges are relatively inexpensive, approximately $5 each. However, these cartridges are labeled as single use. In large-scale analyses, this can quickly add up to a sizable percentage of the analysis budget. Additionally, sizable waste volumes can be generated from these analyses in the form of non-degradable polypropylene plastic. If these cartridges can be re-used, material costs as well as waste volumes can be substantially reduced. However, little is known regarding how the quality of analysis degrades with cartridge re-use. The objective of this project is to evaluate the number of times SPE cartridges can be reused without compromising the results of the subsequent analyses.
Based on a review of prior literature, I identified and developed protocols for extracting analytes (BPA and E2) from water via SPE, then analyzing them with gas chromatography and mass spectrometry (GC-MS). These protocols have been developed to mimic those employed by research labs, industry, and other entities for which the results of this study would be most applicable. The only deviation is the re-use of the cartridge rather than disposal and replacement. One type of commercially available SPE cartridge (Oasis HLB, Waters Inc., Milford, MA) was used and two water types were tested. The water was spiked with fixed concentrations of BPA and E2, and then analyzed by way of SPE/GC-MS. For both water types, I performed multiple SPE runs on 10 cartridges each. I tracked the history of GC-MS peak areas, which indicate apparent analyte concentration. Peak area data were analyzed as a function of the number of analyses performed (run number), and evaluated for statistically significant changes as well as overall trends. Statistically significant change and/or trends would indicate that the cartridge had exceeded the maximum allowable number of re-uses and would thereby identify the number of times the “single-use” cartridge can reliably be re-used.
Peak area history for 20 SPE runs per cartridge for pure water samples and 10 SPE runs for wastewater effluent showed no statistically significant changes or trends on peak area. This indicates that cartridges can be re-used at least 10 times without compromising the integrity of water sample analysis for the EDCs considered in this study.
|
Page generated in 0.0651 seconds