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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Remoção de bisfenol-A por adsorção

Haro, Nathalia Krummenauer January 2013 (has links)
O bisfenol-A (BPA), um monômero usado na fabricação de resinas epóxi e de plásticos de policarbonato, é considerado um potente desregulador endócrino que provoca diversas doenças. O objetivo deste trabalho foi estudar a remoção de BPA, de soluções aquosas através da técnica de adsorção em batelada e em processo contínuo. Também foi investigada a capacidade de regeneração do sorvente utilizado nos testes em batelada. Para isso, foram testados diferentes adsorventes (zeólita em pó e granular modificada com quitosana, zeólita sódica e carvão ativado granular), a fim de determinar qual apresentaria maiores índices de remoção de BPA. Posteriormente foram realizados ensaios de sorção com o sólido escolhido objetivando encontrar as condições mais adequadas de processo considerando os parâmetros de pH, tempo de residência, concentração de sólido sorvente. Ainda, isotermas de equilíbrio para este sistema foram construídas. A adsorção em leito fixo foi avaliada em experimentos via planta piloto de adsorção, segundo a influência de três variáveis: efeito da massa de adsorvente utilizada (5g e 10g), vazão de alimentação (15 mL.min-1 e 20 mL.min-1) e concentração inicial (50 mg.L-1 e 100 mg.L-1). Na regeneração do carvão ativado saturado com BPA, empregaram-se como solventes acetona, n-pentano e diclorometano e também foi utilizada a técnica de ultrassom. As condições de sorção utilizadas foram: pH 6, tempo 60 min, concentração de sorvente 10 g.L-1 e soluções de BPA 10 mg.L-1. A microestrutura externa e a composição elementar semi-quantitativa do carvão ativado antes e após o processo de sorção e regeneração foram analisadas pela técnica de MEV-EDS. No que se refere à sorção, melhores resultados foram encontrados com o carvão ativado granular, atingindo eficiência de remoção de 56,7% em pH 7. O modelo de isoterma de sorção que melhor se ajustou aos dados experimentais foi o modelo de Sips, que forneceu a constante de energia ou afinidade do processo e também a acumulação máxima de BPA no sorvente. Os testes de regeneração mostraram que os melhores agentes regenerativos foram a acetona (100%), com eficiência de remoção de 105,6% e a técnica de ultrassom, a qual apresentou uma eficiência de remoção de 106,4% após um tempo de contato de 30 min. Por ser uma técnica que não gera resíduo, optou-se utilizar o ultrassom para os testes de regeneração em ciclos. O ensaio de tempo de regeneração em banho de ultrassom mostrou que para os tempos de 30, 40, 50 e 60 min de contato a regeneração era muito semelhante. Assim, para os testes de ciclos de sorção-regeneração o tempo de contato utilizado foi de 30 min. Os ensaios de regeneração em ciclos mostraram que após seis (6) ciclos a eficiência de regeneração do sólido sorvente foi de 67,8% e a remoção de BPA obtida ao final desses ciclos foi de 60,9%. Quanto à caracterização do sorvente, as micrografias mostraram que o carvão ativado, antes e após os ciclos de sorção/regeneração (S/R), possui superfícies bastante irregulares, heterogêneas e desordenadas, com elevada porosidade. Ensaios realizados em planta piloto de adsorção mostraram a viabilidade técnica de aplicação do carvão ativado para remoção de bisfenol em processos contínuos, tendo sido possível obter as condições operacionais e a curva de ruptura do sistema. Os resultados indicaram que a adsorção em leito fixo apresentou melhores resultados nas seguintes condições: vazão de alimentação de 20 mL.min-1, concentração inicial de 100 mg.L-1 e 10g de sólido sorvente. / The bisphenol-A (BPA), a monomer used in the manufacture of epoxy resins and polycarbonate plastics is considered a powerful endocrine disrupter which causes various diseases. The objective of this work was to study the removal of BPA from aqueous solutions by adsorption technique in batch and continuous process. The regeneration capacity of sorbents used in batch tests was also investigated. For this purpose, different adsorbents were initially tested (zeolite powder and granular modified with chitosan, sodium zeolite and granular activated carbon) in order to determine which one presents higher removal rates of BPA. After that, sorption tests were carried out with the chosen solid aiming to find the best process conditions considering pH, residence time and sorbent concentration. Hence, equilibrium isotherms were constructed for this system. The fixed bed adsorption was evaluated through adsorption experiments using a pilot plant, according to the influence of three variables: the effect of the mass of the used adsorbent (10g and 5g), flow rate (15 mL.min-1 and 20 mL.min-1) and initial concentration (50 mg.L-1 and 100 mg.L-1). In activated carbon regeneration it was employed acetone, n-pentane and dichloromethane as solvents and the ultrasound technique was also used. The applied sorption conditions were the following: pH 6, time 60 min, sorbent concentration of 10 g.L-1 and BPA solution of 10 mg.L-1. The external microstructure and semi-quantitative elemental composition of the activated carbon before and after the sorption and regeneration were analyzed by SEM-EDS technique. Concerning sorption, the best results were found with granular activated carbon, reaching removal efficiency of 56.7% at pH 7. The sorption isotherm model that best fit the experimental data was the Sips model, which provided constant energy or affinity of the process and also the maximum accumulation of BPA in the sorbent. The regeneration tests showed that the best agents of regeneration were acetone (100%), with removal efficiency of 105.6% and the ultrasound technique, which presented a removal efficiency of 106.4% after a contact time of 30 min. Considering that the technique doesn’t generates waste, it was decided to use the ultrasound tests for regeneration cycles. The regeneration test time in ultrasound bath showed that for contact times of 30, 40, 50 and 60 min the regeneration was very similar. Thus, for testing cycles of sorption-regeneration, the used contact time was 30 minutes. The regeneration cycle tests showed that after six (6) cycles of regeneration efficiency of the solid sorbent was 67.8% and the removal of BPA obtained at the end of these cycles was 60.9%. Regarding characterization of the sorbent, the micrographs showed that the activated carbon before and after cycles of sorption/regeneration (S/R), has very irregular, heterogeneous and disordered surfaces with high porosity. Tests carried out in a pilot plant adsorption showed the technical viability of application of the activated carbon for removal of bisphenol in continuous processes, thus it is possible to obtain operating conditions and the breakthrough curve for this system. These results indicate that the fixed bed adsorption presents best results in the following conditions: feed flow rate of 20 mL.min-1, initial concentration of 100 mg.L-1 and 10 g of solid sorbent.
52

Análise comparativa dos padrões de proliferação e morte celular na próstata ventral de gerbilos sob os efeitos do bisfenol A e cádmio em condições androgênicas normais e após a orquiectomia = Comparative analysis of proliferation and cell death patterns in the ventral prostate of gerbils under the effects of bisphenol A and cadmium in androgenic normal conditions and after orchiectomy / Comparative analysis of proliferation and cell death patterns in the ventral prostate of gerbils under the effects of bisphenol A and cadmium in androgenic normal conditions and after orchiectomy

Colleta, Simone Jacovaci, 1989- 27 August 2018 (has links)
Orientador: Sebastião Roberto Taboga / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-27T10:30:24Z (GMT). No. of bitstreams: 1 Colleta_SimoneJacovaci_M.pdf: 4304217 bytes, checksum: ec5dd4758c1bcc8948cc085490014e3d (MD5) Previous issue date: 2015 / Resumo: A próstata é uma glândula acessória do sistema reprodutor que apresenta desenvolvimento e manutenção regulados por andrógenos e estrógenos. Interferências na ação desses hormônios podem predispor esta glândula a desenvolver doenças como hiperplasia prostática benigna e câncer. O bisfenol A (BPA) e cádmio (Cd) são poluentes ambientais que possuem atividade estereogênica. O BPA e Cd entram no corpo humano, principalmente através da ingestão oral. Assim, o objetivo deste estudo foi avaliar se a exposição ao BPA e ao Cd durante a puberdade pode causar alterações na morfologia, proliferação e morte celular na próstata ventral de gerbilos normais e castrados. Para cumprir estes propósitos foram realizadas técnicas morfológicas, serológicas e immunocitoquímicas (PCNA para detecção de células proliferativas e TUNEL/ caspase-3 para a detecção de células apoptóticas). Os resultados demonstraram que 7 dias depois da exposição ao BPA e Cd, individualmente ou em combinação sob condições androgênicos normais, houve um aumento na altura do epitélio e na espessura da camada muscular lisa (SML). O BPA e Cd individualmente induziram o aumento expressão celular de PCNA e caspase-3. Em associação, o BPA e Cd causam aumento das células imunomarcados por TUNEL. Nos animais castrados, o Cd, individualmente ou em associação com o BPA causou aumento na altura do epitélio, na espessura SML, na área e perímetro nuclear, além da redução no numero de células epiteliais imunomarcadas com PCNA. Além disso, o BPA e Cd combinados, causaram redução das células imunomarcadas por caspase-3. Após 75 dias depois da exposição ao BPA e Cd individualmente ou em combinação, nos animais não castrados, foi observado um aumento na altura epitelial e na espessura da SMC. Todos animais com 120 dias de idade apresentaram focos de lesões intraepitelial prostática (PIN). O BPA promoveu redução da expressão de PCNA nas células do estroma. O Cd, individualmente ou associado com o BPA, causou um aumento das células epiteliais imunomarcadas por PCNA. Além disso, Cd aumentou o numero de células imunomarcadas por TUNEL e diminuiu as células imunomarcadas por caspase-3. Nos animais castrados, a administração BPA e Cd, individualmente ou em combinação, promoveu aumento das células imunomarcadas por TUNEL. Desta forma, podemos concluir que o BPA e o Cd são importantes desreguladores das atividades normais do tecido prostático, alterando os padrões morfológicos, de proliferação e morte celular / Abstract: The prostate is an accessory reproductive system gland presenting the development and maintenance regulated by androgens and estrogens. Interference in the action of these hormones may predispose this gland to develop diseases such as benign prostatic hyperplasia and cancer. The Bisphenol A (BPA) and cadmium (Cd) are environmental pollutants that have estrogenic activity. The BPA and Cd enter in human body, mainly through oral ingestion. Thus, the aim of this study was to evaluate whether exposure to BPA and the Cd during puberty can cause alterations in morphology, proliferation and cell death in normal and castrated gerbils¿ ventral prostate. For this, morphological, serological and immunocitochemical (PCNA for proliferating cells detection and TUNEL/ caspase-3 for apoptotic cells detection) methods were used. The results demonstrated that 7 days after the exposure to BPA and Cd, individually or in combination under androgenic normal conditions, there was an increase in epithelium height and in smooth muscle layer (SML) thickness. The BPA and Cd individually induced increased in PCNA and caspase-3 cellular expression. In association, the BPA and Cd cause increase in TUNEL immunostained cells. In castrated animals, the Cd, individually or in association with the BPA caused an increase in epithelium height, in SML thickness, in area and nuclear perimeter, in addition caused reduction in PCNA immunostained epithelial cells number. In addition, BPA and Cd combined, caused reduction in caspase-3 immunostained cells. Seventy-five days after BPA and Cd exposure, individually or in combination, in non-castrated animals, we observed an increase in epithelial height and the SMC thickness. All animals with 120 days of age had occurrences of lesions prostatic intraepithelial (PIN). The BPA caused a reduction in PCNA stromal cells expression. The Cd, individually or associated with BPA, caused an increase in PCNA immunostained epithelial cells. In addition, Cd increased the number of immunostained cells by TUNEL and decreased the immunostained cells by caspase-3. In castrated animals, the administration BPA and Cd, individually or in combination, increased the immunostained cells by TUNEL. We can conclude that the BPA and Cd are are important agents in endocrine activities changing of normal prostatic tissue patterns, altering the morphological, proliferation and cell death patterns / Mestrado / Histologia / Mestra em Biologia Celular e Estrutural
53

Análise dos efeitos tóxicos do nonilfenol e do bisfenol A em organismos de água doce / The effects of nonylphenol and bisphenol A on freshwater organisms

Mariângela Spadoto 15 February 2013 (has links)
O bisfenol A (BPA) e o nonilfenol (NP), presentes em detergentes, pesticidas, plásticos e resinas, são conhecidos como Endocrine Disrupting-Chemicals (EDCs), Disruptores ou Desreguladores Endócrinos (DE) ou ainda Perturbadores Endócrinos ou Interferentes Endócrinos. O desregulador endócrino pode ser definido como uma substância química exógena ou mistura, que promove alterações em uma ou mais funções do sistema endócrino e na sua estrutura, causando, conseqüentemente, efeitos adversos na saúde de um organismo, ou a sua descendência. Esses compostos estão presentes nas águas de abastecimento, nos efluentes domésticos e industriais. Os desreguladores endócrinos têm ação mimética aos hormônios tanto no sítio de ligação quanto nos efeitos provocados nos seres vivos a eles expostos. Os compostos bisfenol A e nonilfenol foram identificados como desreguladores endócrinos em inúmeros trabalhos em diversos países, porém sendo pouco os efeitos em organismos tropicais. Este estudo teve como objetivo avaliar a toxicidade aguda do bisfenol A e do nonilfenol para Daphnia similis e Ceriodaphnia silvestrii, bem como, a toxicidade crônica para Ceriodaphnia silvestrii e Chironomus xanthus. Nos testes de toxicidade aguda com BPA os valores de CE(I)50; 48h foram de 10,64 mg/L para Daphnia similis e 19,9 mg/L para Ceriodaphnia silvestrii. Nos testes crônicos o valor do CEO obtido para Ceriodaphnia silvestrii foi 1,29 mg/L e para Chironomus xanthus 12 mg/L e o CENO 6 mg/L. Nos testes de toxicidade aguda feitos com NP, os valores de CE(I)50; 48h foram de 0,309 mg/L para Daphnia similis, 0,4520 mg/Lpara Ceriodaphnia silvestrii com solvente água e 0,0541 mg/L com solvente etanol, e 0,03398 mg/L para Ceriodaphnia dubia. O valor do CEO para Ceriodaphnia silvestrii foi 0,0198 mg/L e para Chironomus xanthus foi 100 \'mü\'g/g, com CENO de 50 \'mü\'g/g. Apesar das concentrações encontradas nos testes serem maiores que as encontradas nos estudos que quantificaram esses compostos no ambiente, outros estudos demonstraram que, mesmo em concentrações inferiores as obtidas nesse estudo já ocorrem problemas relacionados com o tempo da muda e com a androgenização do metabolismo de cladóceros. Além disso, a partir dos resultados obtidos com estes testes, pretende-se alertar o poder público sobre os riscos inerentes da presença destes produtos químicos nas águas e da urgência em se adotar novas técnicas no tratamento de efluentes visando à remoção eficaz desses poluentes. / Bisphenol A (BPA) and nonylphenol (NP), present in detergents, pesticides, plastics and resins, are known as Endocrine-Disrupting Chemicals (EDCs), Disruptors or Endocrine Disruptors (ED), Endocrine Disruption or Interferences Endocrine. The endocrine disruptors can be defined as an exogenous chemical substance or mixture, which causes changes in one or more functions of the endocrine system and its structure, causing, therefore, adverse effects on the health of an organism, or its progeny. These compounds are present in the water supply in domestic and industrial effluents. EDs have mimetic action to hormones in both binding site as the effects caused in living beings exposed to them. The compounds bisphenol A and nonylphenol were identified as endocrine disruptors in numerous studies in many countries, but with little effects on tropical organisms. This study aimed to evaluate the acute toxicity of bisphenol A and nonylphenol Daphnia similis and Ceriodaphnia silvestrii, as well as chronic toxicity to Ceriodaphnia silvestrii and Chironomus xanthus. In acute toxicity tests with BPA values EC(I) 50, 48 h were 10.64 mg/L for Daphnia similis and 19.9 mg/L for Ceriodaphnia silvestrii; chronic In the tests the value obtained for the CEO Ceriodaphnia silvestrii was 1.29 mg/L and 12 mg/L Chironomus xanthus CENO and 6 mg/L. In acute toxicity tests made with NP values EC(I) 50; 48h were 0.309 mg/L for Daphnia similis, 0.4520 mg/L for Ceriodaphnia silvestrii solvent and water with 0.0541 mg/L ethanol solvent and 0.03398 mg/L for Ceriodaphnia dubia. The value of the CEO to Ceriodaphnia silvestrii was 0.0198 mg/L and Chironomus xanthus was 100 \'mü\'g/g, with CENO was 50 \'mü\'g/g. Although the found concentrations in the tests are higher than those found in studies to have quantified these compounds in the environment, other studies showed that at concentrations lower than those obtained in this study have problems occur with time and the change of the metabolism of Cladocera androgenization. Also, based on the results obtained with these tests, is intended to alert the public on the risks associated of the presence of these chemicals in the water and the urgency in adopting new techniques in wastewater treatment aiming at the effective removal of these pollutants in water and in the sediment.
54

The Association between Urinary Bisphenol-A, Phthalate Metabolites and Body Fat Composition in US Adults Using NHANES

Corbasson, Iris E 07 November 2014 (has links)
Due to the widespread use of the endocrine disruptors Bisphenol-A (BPA) and phthalates in many plastic consumer goods, medical equipment, and personal care products, more than 95% of the US population show detectable levels of urinary BPA and phthalate metabolites. Both have been linked to increased body mass index (BMI in kg/m2), an inexpensive diagnostic tool for obesity, which may however not reflect body fatness. Since excess body fat is associated with cardiovascular diseases, cancer and type II diabetes, it is important to understand the relationship between body fat composition and exposure to BPA and phthalates, a relationship that is still unknown. Using NHANES 1999-2006 data on adults aged >20 years, we investigated the relationship between urinary BPA (N=2,534), monoethyl-phthalate (mEP, N=5,431), monobutyl-phthalate (mBP), monoethylhexyl-phthalate (mEHP) and monobenzyl-phthalate (mBzP, each N=5,436) measured by high-performance liquid chromatography tandem mass spectrometry, and body fat composition measured as lean mass (LM, grams), fat mass (FM, grams) and percent body fat (%BF) using Dual Energy X-ray Absorptiometry. A multivariable linear regression analysis yielded that independently of BMI, BPA, mBP, and mBzP were inversely associated with LM (quartile 4 b=-862.16 (354.65), -731.76 (248.89), -909.13 (252.32), respectively; all p<0.02, p-trend<0.02); mEHP and FM were inversely associated (quartile 4 b=-297.98 (144.87), p=0.04, p-trend<0.02); BPA, mBP, and mBzP were positively associated with %BF but not clinically significant. These results provide novel insights in the relationship between urinary BPA, phthalates and LM independent of BMI, and it highlights the need for prospective studies establishing temporality of this relationship.
55

SYNTHESES AND ESTROGENICITY STUDY OF DIETHYLSTILBESTROL AND BISPHENOL-A ANALOGS AS POTENTIAL REPLACEMENT FOR BISPHENOL-A AND INVESTIGATION ON NOVEL REACTIONS INDUCED BY IODANE/QUATERNARY AMMONIUM HALIDES

Potturi, Hima 01 August 2011 (has links)
Dynamic isomerization of diethylstilbestrol (DES) makes it difficult to ascertain the active estrogen between its E and Z isomers. An indirect approach has been used in this project to identify the active estrogen. Methoxylated E- and Z-DES (13 and 14) and 9,10-diethylphenanthrene-3,6-diol (15), a closed ring analog of Z-DES, were synthesized and tested for their estrogenicity. The estrogenicity of 13 is higher than that of 14 and 15, which indicates that E-DES is more estrogenic than Z-DES. Dimethylstilbestrol (16), another analog of DES, was also synthesized and tested. Its estrogenicity is lower than that of DES. Non-estrogenic analogs of bisphenol-A were designed based on the observation that (15) is far less estrogenic than DES. Closed ring analogs of bisphenol-A, 3,6-dihydroxy-9,9-dimethylfluorene (34), 2,6-dihydroxy-9,9-dimethylfluorene (35), and 2,7-dhydroxy-9,9-dimethylfluorene (36) were synthesized and they were found to have little or no estrogenicity. An open ring analog of bisphenol-A, 2-(3-hydroxyphenyl)-2-(4-hydroxyphenyl)propane (33) was also synthesized and its estrogenicity is much lower than that of bisphenol-A. Polycarbonate of 36 was also synthesized and its glass transition temperature was measured using differential scanning calorimetry (DSC). Glass transition temperature of polycarbonate of 36 was found to be 199.92 oC, which is about 50o higher than that of bisphenol-A polycarbonate (150 oC). This indicates that polycarbonate of 36 forms a harder plastic than bisphenol-A polycarbonate. Compounds 2,8-dihydroxy-5,5-dioxo-dibenzothiophene (69) and 2,8-dihydroxydibenzothiophene (70) were also synthesized and were tested as non-estrogenic alternatives for bisphenol-S and bisphenol sulfide, respectively. Compound 69 and 70 were found to be less estrogenic than bisphenol-S and bisphenol sulfide respectively agreeing with our hypothesis. Iodane/quaternary ammonium halide in nitromethane was utilized to explore aromatic bromination, N-nitrosation-dealkylation, and benzoate ester formation from benzylamines. Koser's reagent was found to be a suitable iodane for aromatic bromination reaction, whereas for N-nitrosation-dealkylation, IBX gave the best yields. Further, for N-nitrosation-dealkylation reaction, the halides of quaternary ammonium salts play a crucial role. The effectiveness of halides follows F- > Cl- > Br- ~ I-. The lack of N-nitrosation-dealkylation and ester formation in the absence of nitromethane indicates that nitromethane is playing an essential role as well. Yields of benzoate ester from benzyl amines were low (~22%). Optimization experiments will be performed in the future. Plausible reaction mechanisms for these reactions were proposed. Aromatic bromination was thought to be induced either by iodane/halide adduct or by BrOH that was formed from iodane/halide adduct. Ester formation and N-nitrosation-dealkylation were believed to be induced either by alkyl nitrite or by nitrous acid, generated from the reaction of iodane/halide adduct with nitromethane.
56

A REVIEW ON THE ROLE OF A SELECTION OF BISPHENOLS IN ADIPOGENESIS

Palenius, Hildur January 2021 (has links)
Obesity is a growing global problem, and it is now considered to be a health problem with epidemic status. The condition is associated with several serious comorbidities, such as cardiovascular diseases and type 2 diabetes mellitus. This makes it highly relevant to seek for solutions to the obesity issue. Diet and exercise are two important components in the area, but studies are also indicating exposure to chemicals so called obesogens, could contribute as well. Bisphenols are chemicals we are frequently exposed to in our every-day environment, mostly through plastics. In this project, the adipogenic effects from a relevant selection of 8 different bisphenols in vitro were examined by a thorough literature search on published data. Concluding results from this research indicated that the structural analogues of BPA appear to be as problematic as BPA with respect to adipogenesis, and should be used with caution. It was also clearly demonstrated that further studies are needed in order to gain more data and understand their adipogenic impact.
57

Oral Exposure of Bisphenol A During Development Affects Behavior in Adulthood in the Female Prairie Vole (Microtus ochrogaster)

Beach, Elsworth Charles January 2013 (has links)
No description available.
58

Block Copolymers via Reverse Addition-Fragmentation Chain Transfer Polymerization as a Viable Resin for Packaging Coatings

Lascu, Claudia M. 26 June 2015 (has links)
No description available.
59

Adsorption of Bisphenol-s (BPS) from Water Using Activated Carbon

Al-Mashhadani, Suhaib Abdulsattar 24 May 2017 (has links)
No description available.
60

THE INTERACTION OF CHEMICAL AND NATURAL STRESSORS ON CARDIOVASCULAR DYNAMICS OF TELEOST FISH

Cypher, Alysha D. January 2017 (has links)
No description available.

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