Spelling suggestions: "subject:"analytical a'method"" "subject:"analytical 20method""
31 |
Otimização do método lignina brometo de acetila na determinação do teor de lignina em plantas forrageiras e comparação com os métodos lignina detergente ácido e lignina Klason / Improving the acetyl bromide lignin method in determining lignin content in forages and comparison with the methods acid detergent lignin and Klason ligninSantamaria, Marcos Felipe Zuñiga 15 February 2016 (has links)
Técnicas analíticas empregadas para a quantificação do teor de lignina em plantas forrageiras, atualmente em uso, são questionáveis quanto às suas acurácias. O método lignina detergente ácido (LDA), que é um dos métodos mais utilizado em Ciência Animal e Agronomia, apresenta algumas falhas, particularmente devido à parcial solubilização da lignina durante a preparação da fibra em detergente ácido (FDA). A lignina Klason (LK), outro método muito usado, apresenta o inconveniente de mensurar a proteína da parede celular como sendo lignina. Em ambos os procedimentos recomenda-se também mensurar cinzas nos resíduos de lignina. A quantificação da concentração de lignina pelo método espectrofotométrico lignina brometo de acetila (LBA) vem ganhando interesse de pesquisadores no Brasil e no exterior. Nesta metodologia, a lignina da planta contida na preparação parede celular (PC) é solubilizada numa solução a 25% de brometo de acetila em ácido acético e a absorbância mensurada é com luz UV a 280 nm. O valor da absorbância é inserido numa equação de regressão e a concentração de lignina é obtida. Para que esta técnica analítica seja mais aceita pelos pesquisadores, ela deve ser, obviamente, convincente e atrativa. O presente trabalho analisou alguns parâmetros relacionados à LBA em 7 gramíneas e 6 leguminosas, em dois estádios de maturidade. Dentre as diferentes temperaturas de pré-secagem, os resultados indicaram que os procedimentos de 55°C com ventilação e liofilização podem ser utilizados com a mesma eficácia. As temperaturas de 55°C sem ventilação e 80°C sem ventilação não são recomendadas, pois aumentaram os valores de FDA e LDA, possivelmente devido ao surgimento de artefatos de técnica como os compostos de Maillard. No método LBA os valores menores das amostras de leguminosas chamaram a atenção e colocaram em questão se a lignina destas plantas seria menos solúvel no reagente brometo de acetila. Dentre algumas alterações na metodologia da técnica LBA, a utilização do moinho de bolas (para diminuir o tamanho particular) nas amostras de PC não mostrou efeito; a hipótese era melhorar a solubilização da lignina usando partículas menores. O uso de um ultrasonicador, que aumenta a vibração das moléculas e assim, facilitaria a solubilização da lignina no reagente brometo de acetila, melhorou a solubilização da lignina em cerca de 10%, tanto nas gramíneas como nas leguminosas. Foi acoplado um ensaio biológico como referência, a degradabilidade in vitro da matéria seca (DIVMS); e como a lignina está intimamente associada à estrutura fibrosa da parede celular, também foi feito um ensaio de degradabilidade in vitro da fibra em detergente neutro (DIVFDN). Os resultados confirmaram o efeito da maturidade, reduzindo a degradabilidade nas plantas mais maduras, e que o teor de lignina de leguminosas é realmente inferior ao de gramíneas. Os resultados de degradabilidade apresentaram coeficientes de correlação mais elevados com o método LBA, quando foi empregada a técnica do ultrasom; o método LK mostrou os menores coeficientes. Também testou-se, com sucesso, a utilização da FDN, como preparação fibrosa, ao invés de PC. A razão é simples: enquanto que a FDN é amplamente conhecida, a preparação PC não o é. Inquestionável que esta manobra facilitará substancialmente a divulgação desse método, tornando-a mais aceitável pela comunidade científica / Analytical techniques employed to quantify lignin content in forages, currently in use, are questionable as to their accuracies. The method acid detergent lignin (ADL), which is one of the most used method in Animal Science and Agronomy, has some flaws, due to the partial lignin solubilization during the preparation of acid detergent fiber (ADF). The Klason lignin method (KL), another analytical procedure commonly used, has the drawback of measuring the cell wall protein as lignin. In both procedures also are recommended to measure ash content in the lignin residues. Quantification of lignin concentration by the spectrophotometric acetyl bromide lignin method (ABL) has been gaining interest from researchers in Brazil and abroad. In this methodology, the lignin contained in the plant cell wall preparation (CW) is solubilized in a 25% acetyl bromide in acetic acid solution and the absorbance is measured with UV light at 280 nm. The absorbance value is inserted in a regression equation and the concentration of lignin is obtained. For this analytical technique be better accepted by researchers, it must be, obviously, convincing and attractive. This study analyzed some LBA-related parameters in 7 grasses and 6 legumes in two stages of maturity. Among the different temperatures of pre-drying, the results indicated that the procedures at 55°C with ventilation and lyophilization can be used just as effectively. Temperatures of 55 and 80 both without ventilation are not recommended because they increased ADF and ADL values, possibly due to the emergence of technical artifacts such as the compounds of Maillard. The ABL method yielded lower values for legume samples which called into question if the lignin of these plants is less soluble in the acetyl bromide reagent. Among some changes studied in the ABL technique it was the utilization of ball milling in the PC samples, which showed no effect; the hypothesis was to reduce the particle size and thus improve the solubilization of lignin. The use of an ultrasonicator, which increases the vibration of molecules and possibly allowing better solubilization of lignin in the acetyl bromide reagent improved lignin solubilization by about 10%, both in grasses. As a reference, an in vitro dry matter degradability (IVDMD) was conducted. Because lignin is closely linked to the fibrous structure of the cell wall, an in vitro neutral detergent fiber degradability (IVNDFD) test of. Results confirmed the effect of maturity, reducing degradability as the plants matured, and that concentration of lignin is lower in legumes than in grasses. The degradability results showed higher correlation coefficients with the ABL method when the ultrasonicator was used; the KL method showed the lowest coefficients. We also tested, successfully, the use of NDF as a fiber preparation, instead of crude CW. While NDF is widely known, CW preparation is not. This maneuver will substantially facilitate the dissemination of this method, making it more acceptable to the scientific community
|
32 |
Carbon monoxide in biological systems : An experimental and clinical studyÅberg, Anna-Maja January 2007 (has links)
Background: Carbon monoxide (CO) is a toxic gas, but it is also produced endogenously when haem is degraded. When produced in vivo, CO is believed to have positive biological effects. For example it activates the production of cyclic guanosine mono-phosphate and causes vasodilatation. CO is also believed to have anti-inflammatory properties by binding to Mitogen activated protein (MAP) kinase. Several studies in cells, mice and rats support this opinion regarding both the circulatory as well as the anti-inflammatory properties. However, studies in larger animals regarding circulatory effects have demonstrated contradictory results. The only study in humans regarding anti-inflammatory properties of CO could not demonstrate such effects. Methods: This thesis consists of four different models. In paper I a method for analysis of CO in blood was developed using gas chromatography. In paper II a porcine model was used to investigate the elimination time for CO. The pigs in paper II had a high concentration of CO administered via blood, and CO concentrations were followed over time and kinetically parameters calculated. Circulatory parameters were also measured to evaluate if there were any circulatory changes after CO administration. In paper III CO´s anti-inflammatory properties were investigated in an endotoxin-induced systemic inflammatory model in pigs. Paper III was a randomized study where one group inhaled CO and the other group served as controls. Plasma cytokine concentrations were measured and followed over time as an indication of the inflammatory state. In paper IV, CO concentrations in blood from blood donors at the Blood Centre in Umeå were investigated. The blood donors also completed a questionnaire about age, smoking history and other possible sources for exogenous contamination of CO in the blood. Results and conclusions: In paper I we developed a method suitable for analysis of low concentrations of CO in blood. The half-life of CO at levels of 250 µM in pigs was found to be 60 minutes. CO did not show anti-inflammatory effects after an endotoxin-induced systemic inflammation in pigs. In banked blood CO was present at concentrations up to six times higher than normal concentrations. This could be a risk when transfusing such blood to susceptible patients.
|
33 |
Improving Ductility And Shear Capacity Of Reinforced Concrete Columns With Carbon Fiber Reinforced PolymerOzcan, Okan 01 December 2009 (has links) (PDF)
The performance of reinforced concrete (RC) columns during recent earthquakes has clearly demonstrated the possible failures associated with inadequate confining reinforcement. The confinement reinforcement requirements of older codes were less stringent than present standards. Many studies were conducted by applying different retrofitting techniques for RC columns that have inadequate confinement reinforcement. A new retrofitting technique by means of Carbon Fiber Reinforced Polymer (CFRP) was developed and tested in many countries in the last decade. This technique is performed by CFRP wrapping the critical region of columns. The effectiveness of CFRP retrofitting technique was shown in many studies conducted worldwide. In Turkey, the frame members are considerably deficient from the seismic detailing point of view. Therefore, in order to use the CFRP retrofitting technique effectively in Turkey, experimental evidence is needed. This study investigates the performance of CFRP retrofitted RC columns with deficient confining steel and low concrete strength. It was concluded by experimental and analytical results that the CFRP retrofitting method can be implemented to seismically deficient columns. Moreover, two design approaches were proposed for CFRP retrofit design of columns considering safe design regulations.
|
34 |
Desenvolvimento e validação de métodos para o controle analítico do anti-helmíntico ricobendazole®Lima, Tiago do Couto de 16 December 2013 (has links)
Made available in DSpace on 2016-06-02T20:37:50Z (GMT). No. of bitstreams: 1
6282.pdf: 1501471 bytes, checksum: ffde0cd31d022def4bc50e239fc62c78 (MD5)
Previous issue date: 2013-12-16 / This study aims to develop and validate an analytical method for quantification of albendazole sulfoxide in Ricobendazole® product by high performance liquid chromatography (HPLC) ensuring product quality and consumer safety. The HPLC method with which it was possible to quantify the albendazole sulfoxide was carried out employing a phase C18, 250x4, 6 mm, 5μm, Gemini®, and mobile phase of sodium acetate buffer 0.05M pH 5.0 : Acetonitrina (75:25), flow rate 1.0 ml / min and UV detection at 290 nm, the retention time was 5.5 min active and the total time of the analytical run was 10 min. The correlation coefficient (r) of 0.9994, the result recovery method considering an overall mean of three concentrations was 99% linear response range from 80 to 120 μg.mL-1 detection limit of 0.3 μg.mL-1 and the quantitation limit 1.0 μg.mL-1, the results of intermediate precision and robustness show variations lower than 2%. The method was later covalidado efficiency ultra chromatography (CLUE) while maintaining the same mobile phase Mobile phase: Buffer 0.05 M Sodium Acetate: Acetonitrile (75:25) BEH® C18 stationary phase (50mmx2, 1mmx1, 7μm) , flow rate 0.21 mL / min. UV detector 290 nm, retention time was 1.0 min active and the total time of 4.0 min analytical run. The method can be considered efficient, fast and reliable to be used in routine analysis of quality control Ricobendazole®. / O presente trabalho tem como objetivo desenvolver e validar um método analítico para quantificação do Sulfóxido de albendazol no produto comercial Ricobendazole® pelas técnicas de cromatografia líquida de alta eficiência(CLAE) e cromatografia líquida de ultra eficiência (CLUE), assegurando a qualidade do produto técnico e a segurança do consumidor. O método desenvolvido e validado por CLAE tornou possível quantificar o Sulfóxido de albendazol, os parâmetros instrumentais foram fase estacionária Phenomenex C18, 250x4,6mm, 5μm, Gemini® e fase móvel constituída por tampão acetato de sódio 0,05 mol.L-1 pH 5,0:Acetonitrina (75:25), vazão 1,0 mL.min-1 e detecção UV à 290 nm. O tempo de retenção do ativo foi de 5,5 min e o tempo total de corrida analítica foi de 10 min. O coeficiente de correlação(r) de 0,9994,o resultado de recuperação do método considerando uma média geral das três concentrações foi de 99% para uma faixa linear de trabalho entre 80 e 120 μg.mL-1 com limites de detecção e quantificação de 0,3 μg.mL-1 e 1,0 μg.mL-1, respectivamente. Os resultados de precisão intermediária e de robustez apresentaram variações inferiores à 2%. O método de CLAE foi posteriormente testado por cromatografia líquida de ultra eficiência (CLUE) mantendo-se a mesma fase móvel Fase móvel: Tampão Acetato de Sódio 0,05M:Acetonitrila (75:25), fase estacionária Waters BEH® C18 (50mmx2,1mmx1,7μm), vazão 0,21 mL. min- 1,detector UV à 290 nm, tempo de retenção do ativo de 1,0 min e o tempo total de corrida analítica de 4,0 min. O método foi covalidado por CLUE para proporcionar uma maior flexibilidade analítica dentro do controle de qualidade, rapidez na liberação do produto e diminuição de gastos. Foram efetuados estudos no produto visando assegurar a estabilidade do mesmo durante toda sua validade, submetendo a condições forçadas de degradação por hidrólise ácida, básica, oxidação e temperatura. O produto mostrou-se estável não apresentando nenhum produto de degradação tóxico, obtendo assim resultados satisfatórios. Ambos os métodos podem ser considerados eficientes, rápidos e confiáveis para serem empregados em análises de rotina de controle de qualidade do produto comercial Ricobendazole®.
|
35 |
Rôle de la sorption et de la biodégradation dans l'élimination de micropolluants par des procédés d'épuration biologique : application aux molécules anticancéreuses traitées par bioréacteur à membrane / Role of sorption and biodegradation in the removal of micropollutants by biological processes : application to anticancer drugs treated by membrane bioreactorSeira, Jordan 05 April 2013 (has links)
Les travaux de recherche effectués dans le cadre de ce travail de thèse ont eu pour objectif de caractériser le rôle joué par les mécanismes de sorption et de biodégradation dans l’élimination de micropolluants organiques par les boues biologiques, et notamment celles de bioréacteur à membrane. La première étape a consisté en la mise au point d’une méthode d’analyse de molécules anticancéreuses depuis les phases aqueuse et solide des boues. L’extraction des molécules contenues dans la phase aqueuse a été réalisée par une combinaison de cartouches SPE permettant la récupération sélective d’espèces acides, neutres et basiques. L’extraction depuis la phase solide a été rendue possible grâce à l’utilisation de la technique sous solvant pressurisé et à chaud PLE, suivie par une étape de purification directement inspirée de la méthode développée pour la phase aqueuse. Une procédure originale de préparation d’échantillons de boues a été proposée pour estimer rigoureusement le phénomène de sorption. Le modèle de Freundlich est celui qui a donné les corrélations les plus satisfaisantes et a été sélectionné. La détermination des paramètres du modèle a mis en évidence des comportements de sorption différents pour les molécules ciblées, mais toujours caractérisés par des aptitudes de sorption faibles. La mise en relation des propriétés physico-chimiques des molécules, des boues et des paramètres de sorption n’a pas révélé de corrélations évidentes entre ces différents paramètres et ne permet pas de proposer de modèle capable de prédire la sorption en fonction des caractéristiques des boues et des polluants. La caractérisation du comportement d’un cocktail d’anticancéreux lors du traitement par un pilote de bioréacteur à membrane externe a révélé que le mécanisme majeur à l’origine de leur élimination était la biodégradation. Les interactions entre les microorganismes et les micropolluants ciblés sont liées au cométabolisme. Une étude approfondie du mécanisme a révélé que ces mêmes interactions étaient à l’origine d’une limitation de la biodégradation et doivent être intensifiées pour améliorer les performances de traitement sur ce point. / The aim of the present work was to characterize the sorption mechanisms and biodegradation role in the removal of some organic micropollutants (i.e. anticancer drugs) by biological sludges, including those of membrane bioreactor (MBR). The first step consisted in the development of an analytical method for the trace determination of anticancer drugs from sludge aqueous and solid phases. The extraction from the aqueous matrix was performed by a combination of SPE cartridges, allowing the selective recovery of acid, neutral and basic species. The extraction from the solid matrix was possible thanks to an extractive step performed by pressurized liquid extraction, followed by a purification step whose procedure was directly inspired from the method developed for aqueous samples. An original procedure for the conditioning of sludge samples before sorption experiments has been proposed. The Freundlich isotherm gave the satisfactoriest correlations and has been selected. The determination of the model parameters highlights different trends of sorption between targeted compounds, but always characterized by low sorption affinities. Physico-chemical properties of both compounds and sludge did not show any link with sorption parameters. Consequently, it is not possible to propose a predictive model for the sorption of polar micropollutants depending on both compounds and sludge properties. The removal of a “cocktail” of anticancer drugs by treatment through a side stream pilot-scale MBR has been investigated. Biodegradation appeared as the prevailing mechanism and was explained by cometabolic interactions. However, these interactions were also responsible for the limitation of biodegradation phenomenon and must be intensify to enhance the removal of these compounds.
|
36 |
O método analítico para o ensino de leitura em Série de leitura Proença (1926-1928), de Antonio Firmino ProençaGazoli, Monalisa Renata [UNESP] 11 February 2010 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:28:16Z (GMT). No. of bitstreams: 0
Previous issue date: 2010-02-11Bitstream added on 2014-06-13T18:32:35Z : No. of bitstreams: 1
gazoli_mr_me_mar.pdf: 1730797 bytes, checksum: 58d73fc002719a1265bc1374a71c41b4 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Nesta dissertação, apresentam-se resultados de pesquisa de mestrado em educação (Bolsa Capes - março a agosto de 2008; bolsa Fapesp - setembro de 2008 a fevereiro de 2010), vinculada às linhas “Alfabetização” e “Ensino de Língua Portuguesa” do Grupo de Pesquisa e do Projeto Integrado de Pesquisa “História do Ensino de Língua e Literatura no Brasil”, ambos coordenados por Maria do Rosário L. Mortatti. Com o objetivo de contribuir para a compreensão de um importante momento da história do ensino da leitura no Brasil, focalizase a proposta para esse ensino apresentada pelo professor paulista Antonio Firmino de Proença (1880-1946), nos livros didáticos que integram a “Série de leitura Proença”, a saber: Cartilha Proença (1926), Leitura do principiante (1926), 1º. livro de leitura (1926), 2º. livro de leitura (1927), 3º. livro de leitura (1928) e 4º. livro de leitura (1948). Os livros que integram essa série foram publicados pela Editora Melhoramentos (SP) e circularam em diferentes estados brasileiros, dentre os quais, Ceará, Minas Gerais, Pernambuco e Santa Catarina, além de São Paulo, tendo contribuído para a formação de muitas gerações de brasileiros. Mediante abordagem histórica centrada em pesquisa documental e bibliográfica, desenvolvida por meio dos procedimentos de localização, recuperação, reunião, seleção e ordenação de fontes documentais, analisou-se a configuração textual dos livros dessa série, que consiste em enfocar os diferentes aspectos constitutivos de seu sentido. Concluiu-se que, nesses livros, apresentada-se uma proposta de concretização do método analítico para o ensino da leitura diretamente relacionada com outros livros de leitura publicados nas décadas iniciais do século XX, como decorrência da institucionalização desse método, no estado de São Paulo. / This work deals with the results of a Master degree dissertation research related to “Literacy” and “Portuguese Language” of Research Group and Research Integrated Project “History of Language and Literature Teaching in Brazil” both under the leadership of Maria do Rosário Longo Mortatti. Aiming contributing to understand an important of the history of reading teaching in Brazil, it focus on the proposal concerning reading teaching presented by Professor Antonio Firmino Proença (1880-1946), in the didactic books called “Série de leitura Proença”, that is: Cartilha Proença (1926), Leitura do principiante (1926), 1º. livro de leitura (1926), 2º. livro de leitura (1927), 3º. livro de leitura (1928) e 4°. livro de leitura (1948). All those books were published by Editora Melhoramentos (SP) and had circulation in different Brazilian states such as Ceará, Minas Gerais, Pernambuco e Santa Catarina, besides São Paulo, and in this way, they contributed to form many Brazilian generations. Through historical approach centred on documentary and bibliographical investigation, and by means of localizing, retrieving, assembling, selecting and ordering proceedings, those books textual configuration was analysed, that is to say, to focus on different constitutive aspects of their meanings. The conclusion is that in those books, a proposal to make concrete the analytical method for reading teaching is presented, which is directly related to other reading books published at the beginning decades of 20 th century, as a result of the institutionalization of that method in the state of São Paulo.
|
37 |
Otimização do método lignina brometo de acetila na determinação do teor de lignina em plantas forrageiras e comparação com os métodos lignina detergente ácido e lignina Klason / Improving the acetyl bromide lignin method in determining lignin content in forages and comparison with the methods acid detergent lignin and Klason ligninMarcos Felipe Zuñiga Santamaria 15 February 2016 (has links)
Técnicas analíticas empregadas para a quantificação do teor de lignina em plantas forrageiras, atualmente em uso, são questionáveis quanto às suas acurácias. O método lignina detergente ácido (LDA), que é um dos métodos mais utilizado em Ciência Animal e Agronomia, apresenta algumas falhas, particularmente devido à parcial solubilização da lignina durante a preparação da fibra em detergente ácido (FDA). A lignina Klason (LK), outro método muito usado, apresenta o inconveniente de mensurar a proteína da parede celular como sendo lignina. Em ambos os procedimentos recomenda-se também mensurar cinzas nos resíduos de lignina. A quantificação da concentração de lignina pelo método espectrofotométrico lignina brometo de acetila (LBA) vem ganhando interesse de pesquisadores no Brasil e no exterior. Nesta metodologia, a lignina da planta contida na preparação parede celular (PC) é solubilizada numa solução a 25% de brometo de acetila em ácido acético e a absorbância mensurada é com luz UV a 280 nm. O valor da absorbância é inserido numa equação de regressão e a concentração de lignina é obtida. Para que esta técnica analítica seja mais aceita pelos pesquisadores, ela deve ser, obviamente, convincente e atrativa. O presente trabalho analisou alguns parâmetros relacionados à LBA em 7 gramíneas e 6 leguminosas, em dois estádios de maturidade. Dentre as diferentes temperaturas de pré-secagem, os resultados indicaram que os procedimentos de 55°C com ventilação e liofilização podem ser utilizados com a mesma eficácia. As temperaturas de 55°C sem ventilação e 80°C sem ventilação não são recomendadas, pois aumentaram os valores de FDA e LDA, possivelmente devido ao surgimento de artefatos de técnica como os compostos de Maillard. No método LBA os valores menores das amostras de leguminosas chamaram a atenção e colocaram em questão se a lignina destas plantas seria menos solúvel no reagente brometo de acetila. Dentre algumas alterações na metodologia da técnica LBA, a utilização do moinho de bolas (para diminuir o tamanho particular) nas amostras de PC não mostrou efeito; a hipótese era melhorar a solubilização da lignina usando partículas menores. O uso de um ultrasonicador, que aumenta a vibração das moléculas e assim, facilitaria a solubilização da lignina no reagente brometo de acetila, melhorou a solubilização da lignina em cerca de 10%, tanto nas gramíneas como nas leguminosas. Foi acoplado um ensaio biológico como referência, a degradabilidade in vitro da matéria seca (DIVMS); e como a lignina está intimamente associada à estrutura fibrosa da parede celular, também foi feito um ensaio de degradabilidade in vitro da fibra em detergente neutro (DIVFDN). Os resultados confirmaram o efeito da maturidade, reduzindo a degradabilidade nas plantas mais maduras, e que o teor de lignina de leguminosas é realmente inferior ao de gramíneas. Os resultados de degradabilidade apresentaram coeficientes de correlação mais elevados com o método LBA, quando foi empregada a técnica do ultrasom; o método LK mostrou os menores coeficientes. Também testou-se, com sucesso, a utilização da FDN, como preparação fibrosa, ao invés de PC. A razão é simples: enquanto que a FDN é amplamente conhecida, a preparação PC não o é. Inquestionável que esta manobra facilitará substancialmente a divulgação desse método, tornando-a mais aceitável pela comunidade científica / Analytical techniques employed to quantify lignin content in forages, currently in use, are questionable as to their accuracies. The method acid detergent lignin (ADL), which is one of the most used method in Animal Science and Agronomy, has some flaws, due to the partial lignin solubilization during the preparation of acid detergent fiber (ADF). The Klason lignin method (KL), another analytical procedure commonly used, has the drawback of measuring the cell wall protein as lignin. In both procedures also are recommended to measure ash content in the lignin residues. Quantification of lignin concentration by the spectrophotometric acetyl bromide lignin method (ABL) has been gaining interest from researchers in Brazil and abroad. In this methodology, the lignin contained in the plant cell wall preparation (CW) is solubilized in a 25% acetyl bromide in acetic acid solution and the absorbance is measured with UV light at 280 nm. The absorbance value is inserted in a regression equation and the concentration of lignin is obtained. For this analytical technique be better accepted by researchers, it must be, obviously, convincing and attractive. This study analyzed some LBA-related parameters in 7 grasses and 6 legumes in two stages of maturity. Among the different temperatures of pre-drying, the results indicated that the procedures at 55°C with ventilation and lyophilization can be used just as effectively. Temperatures of 55 and 80 both without ventilation are not recommended because they increased ADF and ADL values, possibly due to the emergence of technical artifacts such as the compounds of Maillard. The ABL method yielded lower values for legume samples which called into question if the lignin of these plants is less soluble in the acetyl bromide reagent. Among some changes studied in the ABL technique it was the utilization of ball milling in the PC samples, which showed no effect; the hypothesis was to reduce the particle size and thus improve the solubilization of lignin. The use of an ultrasonicator, which increases the vibration of molecules and possibly allowing better solubilization of lignin in the acetyl bromide reagent improved lignin solubilization by about 10%, both in grasses. As a reference, an in vitro dry matter degradability (IVDMD) was conducted. Because lignin is closely linked to the fibrous structure of the cell wall, an in vitro neutral detergent fiber degradability (IVNDFD) test of. Results confirmed the effect of maturity, reducing degradability as the plants matured, and that concentration of lignin is lower in legumes than in grasses. The degradability results showed higher correlation coefficients with the ABL method when the ultrasonicator was used; the KL method showed the lowest coefficients. We also tested, successfully, the use of NDF as a fiber preparation, instead of crude CW. While NDF is widely known, CW preparation is not. This maneuver will substantially facilitate the dissemination of this method, making it more acceptable to the scientific community
|
38 |
Recuperação de óleo por injeção de polímeros : abordagens experimental, analítica e numérica em pequena escala / Oil recovery by polymer flooding - experimental, analytical and numerical approachesRios, Vinicius de Souza, 1989- 26 August 2018 (has links)
Orientador: Rosângela de Barros Zanoni Lopes Moreno / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica, Instituto de Geociências / Made available in DSpace on 2018-08-26T14:12:49Z (GMT). No. of bitstreams: 1
Rios_ViniciusdeSouza_M.pdf: 4750448 bytes, checksum: f37f3a92613dec5888a4b151fd115ece (MD5)
Previous issue date: 2014 / Resumo: Dadas as práticas atuais de gerenciamento de reservatórios, motivadas pelos altos preços do petróleo e baixa eficiência de métodos convencionais de recuperação, as empresas operadoras têm considerado a aplicação de métodos de recuperação avançada (EOR) cada vez mais cedo na vida produtiva dos seus campos. Neste contexto, a importância de pesquisas e desenvolvimento de métodos avançados como injeção de polímeros tem aumentado fortemente nas últimas décadas. A injeção de polímero é um método químico de recuperação indicado para casos de reservatórios heterogêneos ou em que a razão de mobilidades entre água e o óleo é alta, dita desfavorável. Este método mostra-se bastante eficaz, atuando no aumento da viscosidade da água, que reflete em deslocamentos mais eficientes devido à redução da razão de mobilidades. Visando avaliar o desempenho deste método de recuperação, este trabalho apresenta um estudo da técnica de injeção de polímeros através de três abordagens: experimental, analítica e numérica. O trabalho experimental envolveu testes utilizando uma amostra de arenito, em que se realizou o deslocamento de óleo mineral grau SAE 15W-40, com viscosidade acima de 200 cP em condição ambiente. Como fluido deslocante, utilizou-se uma solução salina (110.000 ppm NaCl) para simular a recuperação através de injeção convencional de água e uma solução salina contendo polímero sintético (1500 ppm HPAM e 110.000 ppm NaCl), visando a simulação do método de injeção de polímeros como método avançado de recuperação. A investigação analítica se deu através da utilização de um modelo baseado na análise de fluxo fracionário, que foi aplicado para estudo dos perfis de saturação e avaliação da recuperação de óleo pela injeção de solução polimérica em diferentes condições. Esta etapa foi auxiliada por um algoritmo, que permitiu a avaliação de diversos cenários de maneira prática através da manipulação dos parâmetros de entrada do código desenvolvido. A etapa numérica foi realizada utilizando software comercial de simulação de fluxo com o objetivo de representar e obter o ajuste de histórico dos testes de deslocamento realizados na etapa experimental, comparando assim os métodos de recuperação e avaliando a capacidade do simulador comercial de representar os fenômenos observados experimentalmente. As abordagens analítica e numérica complementaram o estudo experimental, possibilitando maior compreensão dos fenômenos envolvidos no escoamento da solução polimérica. Além disso, através da sensibilidade adquirida no estudo analítico e ajuste de histórico realizado na etapa numérica, foi possível estimar alguns parâmetros não obtidos experimentalment / Abstract: Due to the current reservoir management practices, motivated by the high oil prices and poor efficiency of conventional recovery methods, the operators have considered the application of enhanced oil recovery (EOR) in the early stage of the productive life of the field In this context, the importance of research and development of enhanced oil recovery methods, as polymer flooding, has strongly increased in the past few decades. Polymer flooding is a chemical recovery method indicated for heterogeneous reservoirs or reservoirs where mobility ratio between water and oil is high, said unfavorable. This method presents great results, increasing the water viscosity and leading to higher sweep efficiency, due to a reduction of the mobility ratio. This work aims to evaluate the performance of polymer flooding through a study based on three approaches: experimental, analytical and numerical. The experimental work involved displacement tests performed in a sandstone sample, using mineral oil of 200 cp at room temperature. As displacing fluid, a brine (110.000 ppm NaCl) was used to simulate a conventional recovery method and a polymer solution (1500 ppm HPAM e 110.000 ppm NaCl) was injected to simulate the polymer flooding recovery method. The analytical investigation was done using fractional flow calculations applied to polymer flooding. An analytical model was applied to study the saturation profiles and evaluate the oil recovery by polymer flooding at different conditions. This study used an algorithm, which allowed the evaluation of polymer flooding at different scenarios in a practical and fast way. The numerical evaluation was performed using a commercial simulator, aiming to represent and obtain the history match of the displacement tests done in the experimental work and evaluate the capacity of the simulator to represent the phenomena observed experimentally. The analytical and numerical approaches complemented the experimental study, allowing better comprehension of the phenomena present in the polymer flooding method. Furthermore, from the sensitivity acquired in the analytical study and the history match in the numerical study, it was also possible to estimate some parameters not obtained in the lab / Mestrado / Reservatórios e Gestão / Mestre em Ciências e Engenharia de Petróleo
|
39 |
Etude de profils en adduits à l'ADN comme biomarqueurs potentiels d'exposition aux polluants aériens en milieu urbain dans une approche de type adductomique / Study of DNA adducts profiles as potential biomarkers of exposure to urban air pollutants in an adductomic approachAlamil, Helena 23 October 2019 (has links)
De nombreuses études dans la seconde moitié du 20ème siècle, ont mis en évidence que des génotoxiques cancérogènes réagissent avec l'ADN pour former par liaison covalente des adduits qui sont impliqués dans le processus cancérigène. Bien qu’il existe des preuves convaincantes de la présence de multiples adduits à l'ADN dans les poumons de sujets exposés au tabagisme ou en milieu professionnel à un aldéhyde donné, il est évident que c'est un domaine dans lequel des recherches supplémentaires ont été nécessaires. L’objectif de ce travail de thèse est d’établir des profils d’adduits exocycliques à l'ADN induits par le mélange d’aldéhydes, qui pourraient à terme être considérés comme un marqueur génotoxique de l’exposition aux aldéhydes, tant endogène qu’environnemental. Pour cette raison, nous avons validé une méthode en UHPLC-MS/MS rapide, sensible et précise en utilisant la dilution isotopique, pour la quantification à l’état de trace de 9 adduits exocycliques à l’ADN dérivés de 8 principaux aldéhydes exogènes et endogènes, notamment le formaldéhyde, l’acétaldéhyde, l’acroléine, le crotonaldéhyde, le malondialdéhyde, le 4-hydroxy-2-nonénal, le glyoxal et le méthylglyoxal. Ces adduits ont été synthétisés et purifiés ainsi que leurs homologues marqués au 13C10, 15N5, identifiés et quantifiés par le biais des courbes d'étalonnage allant de 0,25 à 250 ng/mL d'adduits dans l'eau et l'ADN afin de décrire les effets matrice. Des échantillons de contrôle qualité ont été préparés et analysés afin de vérifier l'exactitude et la précision de la méthode dans des situations de répétabilité et de fidélité intermédiaire. L'absence de contamination croisée a également été démontrée. La méthode est capable de différencier les 9 analytes d'intérêt et leurs étalons internes en utilisant pour chaque analyte une transition de quantification et une seconde de confirmation. Cette méthode a été validée selon les recommandations de l'Agence Européenne des Médicaments concernant les méthodes bioanalytiques. Elle répond à tous les critères essentiels pour garantir l'acceptabilité des performances et la fiabilité des résultats d'analyse. Cette méthode est la toute première validée et peut être utilisée en adductomique dans le cadre d'études sur l'exposome. En plus, nous avons simultanément mesuré par une approche in vitro les 9 adduits exocycliques dans de l’ADN de thymus de veau exposé à de différentes concentrations de chaque aldéhyde seul ou en mélanges équimolaires. Cette approche nous a permis d’établir des relations dose-dépendantes pour tous les aldéhydes à l’exception du malondialdéhyde et du méthylglyoxal. Une relation dose-réponse a également été observée avec les mélanges équimolaires d’aldéhydes. Elle a permis de définir des réactivités différentes des aldéhydes en mélange vis-à-vis de l’ADN. Les profils de ces adduits exocycliques ont été également déterminés dans l'ADN de sang de fumeurs et de non-fumeurs. La fumée de cigarette contient plusieurs aldéhydes connus de se lier par covalence aux bases de l’ADN, ainsi l’adduit à l’ADN peut être considéré comme biomarqueur d’exposition au tabac. Des différences significatives dans les niveaux d’adduits ont été obtenues entre l’ADN des fumeurs et celui des non-fumeurs à l’exception de l’adduit induit par le malondialdéhyde. Des corrélations ont été établies entre chaque adduit et les marqueurs de la consommation tabagique sans aucune corrélation significative de la totalité des adduits avec un marqueur spécifique. Par ailleurs, nous avons montré que l’exposition au formaldéhyde, au butanal et au benzaldéhyde a eu un effet sur les concentrations du MDA urinaire mesurées chez les policiers libanais stationnés au carrefour pendant 7 h par jour et après exposition de 5 jours aux émissions du trafic routier. Une augmentation du MDA plasmatique a été décrite ; les années de travail avaient une incidence sur les concentrations de ce biomarqueur. / Many studies in the second half of the 20th century have shown that genotoxic carcinogens, either directly or after metabolic activation, react with DNA to form covalently bonded adducts that are absolutely central in the carcinogenic process. Although there is compelling evidence of the presence of multiple DNA adducts in the lungs of subjects exposed to smoking or occupational exposure to a given aldehyde, it is clear that this is an area in which further research has been necessary. The aim of this thesis is to establish exocyclic DNA adducts profiles induced by the mixture of aldehydes, which could eventually be considered as a genotoxic marker of aldehyde exposure, both endogenous environmental. For this reason, we have validated a fast, sensitive and precise method on liquid chromatography coupled to mass spectrometry in tandem mode (UHPLC-MS/MS) using isotopic dilution, for trace quantification of 9 exocyclic DNA adducts derived from 8 major exogenous and endogenous aldehydes, including formaldehyde, acetaldehyde, acrolein, crotonaldehyde, malondialdehyde, 4-hydroxy-2-nonenal, glyoxal and methylglyoxal. These adducts were synthesized and purified as well as their labeled homologues, identified and quantified through standard curves ranging from 0.25 (LLOQ) to 250 ng/mL (ULOQ) adducts in water and in DNA to describe the matrix effects. Quality control (QC) samples were prepared and analyzed to verify the accuracy and precision of the method in repeatability and intermediate fidelity situations. The absence of cross-contamination has also been demonstrated. The method is able to differentiate the 9 analytes of interest and their internal standards using for each analyte a quantification transition and a confirmation transition. This method has been validated according to the recommendations of the European Medicines Agency (EMA) concerning bioanalytical methods. It meets all the essential criteria to guarantee the acceptability of the performances and the reliability of the analysis results. This method is the very first validated and can be used in adductomics in the context of studies on the exposome. In addition, the exocyclic adducts were simultaneously measured by an in vitro approach in calf thymus DNA exposed to different concentrations of each aldehyde apart or in equimolar mixtures. This approach allowed us to establish dose-dependent relationships for all aldehydes with the exception of malondialdehyde and methylglyoxal. A dose-response relationship was also observed with equimolar mixtures of aldehydes. It made it possible to define different reactivities of aldehydes in mixture versus DNA. The profiles of these exocyclic adducts were also determined in the blood DNA of smokers and non-smokers. Cigarette smoke contains several aldehydes known to covalently bind to DNA bases, so the DNA adduct may be considered as biomarker of tobacco exposure. Significant differences in adducts levels were obtained between smokers and non-smokers DNA with the exception of malondialdehyde-induced DNA adduct. Correlations were established between each adduct and smoking-related markers without any significant correlation of all adducts with a specific marker. Furthermore, we have shown that exposure to formaldehyde, butanal and benzaldehyde had an effect on the concentrations of urinary MDA measured in Lebanese police stationed at the intersection for 7 hours a day and after 5-day exposure to road traffic. An increase in plasma MDA has been described; years of work had an impact on the concentrations of this biomarker. These results are promising and it would be interesting to validate in population the profile of 9 exocyclic adducts as biomarkers of exposure to both exogenous and endogenous aldehydes as part of an adductomic approach to understand the carcinogenic risk in relation to aldehydes exposures in urban areas.
|
40 |
Développement d'une nouvelle méthode analytique du formaldéhyde dans l'air basée sur un dispositif microfluidique / Development of new gaseous formaldehyde analytical method based on a microfluidic deviceGuglielmino, Maud 17 October 2014 (has links)
Le formaldéhyde (HCHO) est un polluant majeur de l’air intérieur. L’objectif de cette thèse est de réaliser les avancées scientifiques et technologiques nécessaires à l’obtention d’une méthode analytique basée sur un dispositif microfluidique de mesure du formaldéhyde dans l’air associant précision, sélectivité, rapidité d’analyse avec pour objectif majeur une autonomie suffisante sur de longues durées, typiquement un mois. Le principe de la méthode reposait initialement sur trois étapes clés, à savoir le piégeage du formaldéhyde gazeux en solution, la réaction du formaldéhyde avec un agent dérivatif, puis la détection du produit de dérivation par colorimétrie ou fluorimétrie. La méthode a finalement évolué vers seulement deux étapes distinctes grâce à l’utilisation d’un dispositif microfluidique innovant dans lequel le piégeage et la réaction ont lieu simultanément. L’étude des performances analytiques du dispositif a permis de valider la méthode développée pendant cette thèse. / Formaldehyde (HCHO) is a major pollutant in indoor air. The objective of this work is to realize the scientific and technological advances required to obtain an analytical method based on a microfluidic device to measure air formaldehyde combining precision, selectivity, analysis speed with for major objective a sufficient autonomy on a long time, typically one month. The principle of the method was initially based on three key steps, the gaseous formaldehyde uptake in solution, the formaldehyde derivatization reaction, then the detection of reaction product by colorimetry or fluorimetry. The method has finally advanced toward only two definite steps thanks to the use of an innovative microfluidic device in which uptake and reaction take place simultaneously. The study of analytical performances of the device allows to validate the method developedduring this work.
|
Page generated in 0.0495 seconds