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Millisecond H/D Exchange Combined with Electrospray Ionization Mass Spectrometry to Study Three Dimensional Structure of ProteinHuang, Ming-Wei 23 June 2003 (has links)
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Utilização de adutos de Baylis-Hillman em reações catalisadas por paladio : estudos mecanisticos sobre a reação de Baylis-Hillman empregando ESI-MS (/MS) / Utilization of Baylis-Hillman Adducts in palladium catalyzed reactions: mechanistic studies concerning the Baylis-Hillman reaction employing ESI-MS (/MS)Pavam, Cesar Henrique 03 January 2005 (has links)
Orientador : Fernando Coelho / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-04T19:13:37Z (GMT). No. of bitstreams: 1
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Previous issue date: 2005 / Resumo: O presente trabalho pode ser dividido em duas partes, ambas abordando a química de adutos de Baylis-Hillman. A primeira parte trata da reatividade destas moléculas frente a complexos de paládio em condições catalíticas de reação. Assim, empregamos adutos de Baylis-Hillman aromáticos halogenados na posição orto como substratos em reações de Heck intramoleculares, em condições reacionais diversas, visando a construção de esqueletos indânicos. Contudo, não obtivemos os produtos esperados na maioria das condições estudadas. Muito provavelmente, o modelo de ciclização 5-endo-trig, cineticamente desfavorecido, tenha inviabilizado nossa abordagem. Em continuação a este trabalho, empregamos estes mesmos substratos em reações de cic!ocarbonilação catalisadas por complexos do tipo Pd-tri-terc-butilfosfina em meio básico, visando a síntese de lactonas enólicas densamente funcionalizadas. Com esta abordagem, obtivemos diversos ftalidos (de naturezas estéreas e eletrônicas variadas), uma cicloexanona, um álcool alílico e uma b-espiro-Iactona em rendimentos de bons a excelentes. Estas reações procedem segundo transformações seqüenciais distintas catalisadas por paládio (ciclocarbonilação/isomerização no caso dos ftalidos e dupla ciclocarbonilação quimiosseletiva no caso da b-espiro-Iactona). No que se refere à preparação dos ftalidos, o modelo de ciclização observado foi o 5-exo-trig, explicando assim a dicotomia na reatividade observada entre os complexos aril-paládio e acil-paládio derivados de adutos de Baylis-Hillman. A segunda parte da presente Dissertação de Mestrado trata do estudo mecanístico da reação de Baylis-Hillman empregando espectrometria de massas com ionização por eletrospray (ESI-MS) e ESI-MS/MS (MS tandem). Esta técnica nos permitiu comprovar pela primeira vez o mecanismo desta reação, com a detecção e caracterização estrutural de todos os intermediários zwitteriônicos transientes do ciclo catalítico da reação de Baylis-Hillman, em suas formas protonadas em solução metanólica. / Abstract: The present work can be separated in two distinct parts, both concerning the chemistry of Baylis-Hillman adducts. The first part deals wíth the reactivity of these molecules facing palladium complexes in catalytic reaction conditions. In this way, we have employed aromatic orto halogenated Baylis-Hillman adducts as substrates for intramolecular Heck reactions, in severaI reaction conditions, aiming the construction of indanic frameworks. However, the expected products were not obtained at all in most of the studied catalytic systems. Probably, the 5-endo-trig cyclization model, kinetically disfavored, has been disfavored our approach. In continuation of this work, we employed these same substrates in cyclocarbonylation reactions catalyzed by Pd-tri-tert-butylphosphine type complexes in basic media, owing the synthesis of highly functionalized enol lactones. With this approach, we were able to synthesize severaI phtalides (with different steric and electronic properties), a cyclohexanone derivative, a b-spiro-Iactone moiety, as well an allylic alcohol compound, in good to excellent yields. These reactions proceed accordingly essentially different tandem transformations catalyzed by palladium (cyclocarbonylation/isomerization in the case of phtalides and double chemoselective cyclocarbonylation in the case of the b-spiro-Iactone). In the specific case of the phtalides, the cyclization model 5-exo-trig was observed, explaining therefore the dichotomy in the reactivity between the aryl- and acyl palladium complexes derived from the same Baylis-Hillman adducts precursors. The second part of the present Dissertation deals with the mechanistic study of the Baylis-Hillman reaction employing mass spectrometry with electrospray ionization (ESI-MS), as well as tandem mass spectrometry (ESI-MS/MS). This approach allowed us to probe, for the first time, the mechanism of this reaction, through the detection and structural characterization of all the zwitterionic intermediates involved in the catalytic cycle of the Baylis-Hillman reaction, in their protonated forms in methanolic solution. / Mestrado / Quimica Organica / Mestre em Química
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Perspectivas mecanisticas de reações organicas catalisadas por paladio : Heck, oxa-Heck e acoplamento de Buchwald-Hartwig por ESI-MS/MS / Mechanistic insights of organic reactions catalyzed by palladium : Heck, oxa-Heck and Buchwald-Hartwig coupling by ESI-MS/MSVaz, Boniek Gontijo 13 August 2018 (has links)
Orientador: Marcos Nogueira Eberlin / Dissertação (mestrado)- Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-13T13:04:08Z (GMT). No. of bitstreams: 1
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Previous issue date: 2009 / Resumo: A espectrometria de Massas por eletronspray (ESI-MS) tornou-se um método prático para o estudo de mecanismos reacionais em solução. Neste trabalho importantes reações catalisadas por paládio: reação de Heck-Mizoroki, oxa-Heck e o acoplamento de Buchwald-Hartwig foram monitoradas por ESI-MS visando interceptar espécies que comprovam as atuais propostas mecanísticas ou que abram caminho para novas propostas para estas reações. O monitoramento das reações foi realizado no modo off-line, acompanhamento da reação em intervalos pré-definidos de tempo, no qual alíquotas das soluções reacionais foram retiradas e diluídas em solventes apropriados e injetados por infusão direta no QTOF. Importantes intermediários reacionais destas reações foram interceptados por ESI-MS e caracterizados por ESI-MS/MS, o que possibilitou confirmar as espécies catalíticas responsáveis pela formação da ligação carbono-carbono na reação de Heck-Mizoroki, os principais intermediários para proposta mecanística desta reação e as atuais propostas da reação oxa-Heck e do acoplamento de Buchwald-Hartwig. No caso da reação oxa-Heck, os paladaciclos interceptados são os primeiros indícios experimentais para atual proposta mecanística desta interessante transformação / Abstract: Eletronspray ionization mass spectrometry (ESI-MS) has become a practical tool to study reaction mechanisms in solution. In this work important reactions catalyzed by palladium: Heck-Mizoroki reaction, oxa-Heck reaction and Buchwald-Hartwig coupling were monitored by ESI-MS to intercept transient intermediates that show the current mechanistic proposals or to open the way for new proposals for these reactions. These reaction was monitored in offline mode, whereas aliquots of the reaction solutions were withdrawn and diluted in appropriate solvents and injected by direct infusion at the Q-TOF in pre-defined intervals of time. Important intermediates from these reactions were intercepted by ESI-MS and characterized by its tandem version ESI-MS/MS, which allowed confirming the catalytic species responsible for the formation of carbon-carbon bond in the Heck-Mizoroki reaction, the main intermediaries mechanistic proposal from this reaction and the current proposals of oxa-Heck reaction and the Buchwald-Hartwig coupling. In oxa-Heck reaction, the intercepted palladacycles are the first experimental evidence for this current mechanistic proposal for this interesting transformation / Mestrado / Quimica Organica / Mestre em Química
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Desenvolvimento e aplicação de um novo método de extração de resíduos de antibióticos presentes em carne de frango / Development and application of a new extraction method for antibiotic residues in chicken meatVinicius Adriano Coelho 21 July 2014 (has links)
A avicultura de corte brasileira tem apresentado elevados índices de crescimento. No intuito de garantir uma maior eficiência da produção de aves, medicamentos veterinários são administrados para tratamento e prevenção de doenças. A coccidiose é uma dessas doenças, a qual é causada por várias espécies do protozoário do gênero Eimeria. Os poliéteres ionóforos são antibióticos largamente administrados no controle desses microrganismos. No entanto, a administração contínua de doses subterapêuticas dessa classe de fármacos pode acarretar no acúmulo de resíduos nos tecidos dos frangos de corte. No intuito de garantir a segurança dos consumidores, são definidos Limites Máximos de Resíduos (LMRs) por órgãos internacionais como: Food and Drug Administration (FDA), Commission Regulation, Codex Alimentarius; e nacionais como Ministério da Agricultura Pecuária e Abastecimento (MAPA). Dessa forma, este estudo teve por objetivo o desenvolvimento, validação e aplicação de um método para determinação em peito de frango de resíduos de Lasalocida (LAS), Monensina (MON), Salinomicina (SAL) e Narasina (NAR) por cromatografia líquida acoplada a espectrometria de massas sequencial com ionização por eletrospray (LC-ESI-MS/MS). Nigericina (NIG) foi utilizada como padrão interno do método analítico. As amostras foram liofilizadas, trituradas e tamisadas, sendo utilizadas no método amostras com tamanho de partículas entre 125 ?m e 250 ?m. Os resíduos foram extraídos com metanol e uma alíquota do extrato foi evaporada e reconstituída para análise em LC-ESI-MS/MS no modo positivo de monitoramento de reação selecionada (SRM). A etapa de clean up foi realizada por meio de filtração do extrato em membrana de PTFE 0,22 ?m. O método apresentou-se linear no intervalo de concentração de 0,0 a 40,0 ?g kg-1 para LAS, de 0,0 a 20,0 ?g kg-1 para MON, de 0,0 a 200,0 ?g kg-1 para SAL e de 0,0 a 30,0 ?g kg-1 para NAR. Para todos os antibióticos o coeficiente de correlação linear (r) esteve de acordo com as diretrizes para métodos bioanalíticos (r >= 0,98). A repetitividade foi avaliada em três concentrações de fortificação para cada antibiótico ionóforo, sendo realizada em três dias consecutivos. Foi obtida boa reprodutibilidade intralaboratorial, com coeficiente de variação (CV) de 4,5% para NAR (22,5 ?g kg-1) e 15,2% para LAS (10,0 ?g kg-1). A recuperação ficou acima de 90,0% para todos os antibióticos, sendo de 91,5% para LAS (10,0 ?g kg-1) e 99,1% para MON (15 ?g kg-1). Valores satisfatórios para o limite de decisão (CC?) e capacidade de detecção (CC?) foram obtidos, sendo CC? de 11,8 ?g kg-1 e 115,2 ?g kg-1 para MON e SAL, respectivamente, e CC? de 13,6 ?g kg-1 e 130,3 ?g kg-1 para os mesmos antibióticos. Os limites de detecção (LD) e os limites de quantificação (LQ) foram determinados a partir de dados da curva de calibração. Todos os antibióticos apresentaram LQ inferior ao seu respectivo LMR. O método foi aplicado em 18 amostras disponíveis comercialmente em Ribeirão Preto, SP. De todas as amostras analisadas apenas uma apresentou resíduo de NAR com concentração acima do seu respectivo LD. / The Brazilian poultry industry has shown high rates of growth. In order to ensure greater efficiency of poultry production, veterinary drugs are administered for the treatment and prevention of diseases. Coccidiosis is one of those diseases, which is caused by various species of protozoa of the genus Eimeria. Polyether ionophore antibiotics are widely administered to control these microorganisms. Continuous administration of subtherapeutic doses of this class of drugs may result in the accumulation of residues at low concentration levels in the tissues of broiler. In order to ensure consumer safety, are set Maximum Residue Limits (MRLs) by international organizations such as Food and Drug Administration (FDA), Commission Regulation (EU), Codex Alimentarius; and national such as Ministério da Agricultura e Pecuária (MAPA). Thus, this study aimed to develop, validate and apply a simple method for determination of residues of Lasalocid (LAS), Monensin (MON), Salinomycin (SAL) and Narasin (NAR) in chicken meat by liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Nigericin (NIG) was used as qualitative internal standard. Samples were lyophilized, powdered and sieved. Particles size between 125 ?m and 250 ?m were used. Residues were extracted with methanol and aliquots of the extracts were evaporated and reconstituted for injection in the LC-ESI-MS/MS operated in positive selected reaction monitoring (SRM). From the molecular ion were obtained two fragment ions and that of higher relative abundance was used in quantification process. Clean-up step was performed by filtration on 0.22 ?m PTFE membrane. In the validation process, this method showed linearity over the concentration range from 0.0 to 40.0 ?g kg-1 for LAS; 0.0 to 20.0 ?g kg-1 for MON; 0.0 to 200.0 ?g kg-1 for SAL and 0.0 to 30.0 ?g kg-1 for NAR. For all antibiotics the coefficient of linear correlation (r) was in accordance with the guidelines for bioanalytical methods (r >= 0.99). The intra-day precision was evaluated at three spiked concentrations for each ionophore antibiotic and was determined in three consecutive days. Good inter-day precision was obtained, with relative standard deviations from 4.5% for NAR (22.5 ?g kg-1) and 15.2% for LAS (10.0 ?g kg-1). For all antibiotics recovery above 90.0% was obtained, which were 91.5% for LAS (10.0 ?g kg-1) and 99.1% for MON (15.0 ?g kg-1). Satisfactory results of decision limit (CC?) and detection capability (CC?) were determined, which were CC? 11.8 ?g kg-1 and 115.2 ?g kg-1 for MON and SAL, respectively; CC? 13.6 ?g kg-1 and 130.3 ?g kg-1 for the same drugs. The limit of detection (LD) and limit of quantification (LQ) were determined from data of the calibration curve. All the LQs were remarkably below the MLRs for each antibiotic. The method was applied to 18 samples acquired in Ribeirão Preto, SP. Of all analyzed samples only one exhibited traces of NAR with concentration above its respective LD. Thus, the proposed method can be applied in routine analysis on samples of commercial chicken meat.
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Análise multirresíduos de pesticidas em tomate utilizando LC-MS/MS e avaliação dos efeitos de lavagem na descontaminação / Multiresidue analysis of pesticides in tomatoes using LC-MS/MS and evaluation of the effects of washing in decontaminatingGraziela Cristina Rossi de Moura Andrade 03 July 2013 (has links)
Os pesticidas têm sido largamente empregados na agricultura para controle de pragas, doenças e ervas daninhas. O uso intensivo de pesticidas nas culturas de tomates, desrespeitando as boas práticas agrícolas, tem causado preocupações quanto à provável contaminação do produto final e muitos métodos multirresíduos têm sido empregados para avaliar e determinar os níveis de resíduos em amostras de alimentos. Para tanto, o objetivo deste estudo foi a validação do método usando QuEChERS no preparo de amostra e LC-MS/MS para a quantificação de resíduos de 61 pesticidas de diferentes classes químicas em tomate. A detecção foi realizada utilizando espectrômetro de massas no modo MRM dinâmico, o tempo de análise foi de 13 min com coluna analítica recheada com partículas de 1,8 \'mü\'m de partícula. Dos 61 pesticidas estudados, 46 estão de acordo com os parâmetros de validação da Comissão Européia e Anvisa, 15% dos pesticidas validados apresentaram efeito matriz médio e as recuperações ficaram entre 87 e 116% e coeficiente de variação de 5 a 17%. Mais de 85% dos compostos investigados apresentaram limites de detecção igual ou menor que 5 \'mü\'g kg-1 e de quantificação igual ou menor que 10 \'mü\'g kg-1. Foram analisadas 58 amostras de tomate coletadas em supermercados da cidade de Piracicaba, SP, Brasil. Doze compostos foram detectados em trinta e cinco amostras (60% do total analisado), todos abaixo do limite máximo de resíduos permitido no Brasil para acefato, acetamiprido, azoxistrobina, benalaxil, bromuconazol, diflubenzurom, imidacloprido, iprodiona, procloraz e tiametoxam, e 15 amostras positivas para metamidofós e 1 para oxamil, que não possuem uso autorizado para a cultura de tomate. Foi realizado um estudo de lavagem de tomates contaminados com produtos formulados (8 pesticidas) com água, solução com 10% de vinagre e com 10% de bicarbonato de sódio e analisada a casca e polpa, para avaliar a capacidade de remoção de cada procedimento. Todos os tratamentos de lavagens (n=3) diferiram estatisticamente para todos os pesticidas avaliados (n=8), com exceção do fipronil, para o qual as lavagens com solução de 10% de bicarbonato de sódio e água não apresentaram diferença no nível de significância de 5%. A lavagem com água ou outras soluções antes do consumo é indicada para a redução de resíduos de pesticidas em tomate e a retirada da casca também contribui para essa redução / Pesticides have been widely used in agriculture to control pests, diseases and weeds. The intensive use of pesticides in tomato crops disrespecting good agricultural practices have been causing concerns about the possible contamination of the final product and many multiresidue methods have been used in order to evaluate and determine the levels of residues in food samples. Therefore, the aim of this study was validate the method using QuEChERS sample preparation and LC-MS/MS for quantification of 61 pesticides residues from different chemical classes in tomato. Detection was performed using mass spectrometry in dynamic MRM mode, run time had 13 min and analytical column packed with 1,8 \'mü\'m particles. Of the 61 pesticides studied, 46 are in accordance with the validation parameters of the European Commission and ANVISA, 15% of the validated pesticides presented matrix effect, recoveries were between 87 and 116% and coefficient of variation 5 to 17%. More than 85% of the compounds investigated showed limits of detection less or equal than 5 \'mü\'g kg-1 and the limits of quantification less or equal than 10 \'mü\'g kg-1. 58 real samples of tomato were analyzed and collected in supermarkets in Piracicaba, SP, Brazil. Twelve compounds were detected in thirty-five samples (60% of the total analyzed), all below the maximum residue limit allowed in Brazil for acephate, acetamiprid, azoxystrobin, benalaxyl, bromuconazole, diflubenzuron, imidacloprid, iprodione, prochloraz and thiamethoxam, and 15 positive samples of methamidophos and 1 for oxamyl, which are not authorized to use at the culture of tomatoes. A wash study was conducted with spiked tomatoes using formulated products (8 pesticides) with water, 10% acetic acid, 10% sodium bicarbonate solution and analyzed concentration in the peel and pulp, in order to evaluate the capacity to remove pesticides in each procedure. All wash treatments (n= 3) differed significantly for all pesticides evaluated (n= 8), with the exception of fipronil, which the washing with 10% of sodium bicarbonate solution and water no showed difference in the level of significance 5%. The washing with water or other solutions before consumption is indicated for the reduction of pesticide residues in tomatoes and the peeling also contributes to this reduction
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Aplicação da espectrometria de massas na avaliação da composição química de vinhos e uvas / Application of mass spectrometry in determination of chemical composition of wine and grapeSilva, Flamys Lena do Nascimento, 1979- 22 August 2018 (has links)
Orientador: Marcos Nogueira Eberlin / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-22T17:49:00Z (GMT). No. of bitstreams: 1
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Previous issue date: 2013 / Resumo: As variedades de uvas do gênero Vitis vinífera, incluindo a uva Syrah, são amplamente utilizadas na vinificação. O híbrido (Máximo-IAC 138-22), obtida do cruzamento entre Syrah e Seibel 11342 tem mostrado grande capacidade de adaptação ao clima de São Paulo e, aparentemente, produz um vinho de boa qualidade. A primeira parte deste estudo consistiu em comparar a composição volátil no headspace do vinho tinto paulista com outros vinhos originados da casta fina Syrah de diferentes regiões do mundo. Para isso foi empregada a técnica de microextração em fase sólida (SPME) com a cromatografia em fase gasosa acoplada à espectrometria de massas (GC-MS). Na segunda parte foi estudado o perfil fenólico de vinhos empregando a técnica de ionização por eletrospray (ESI) acoplada com a espectrometria de massas de ressonância ciclotrônica de íons com transformada de Fourier (FT-ICR MS) que permitiu a detecção de milhares de compostos polares no vinho sem separação cromatográfica e simples preparo de amostra. Constatou-se que o vinho paulista possui um perfil fenólico similar aos outros vinhos comerciais da uva Syrah. No terceiro e quarto estudos empregou-se a técnica ESI-MS por inserção direta para quantificar os ácidos orgânicos em vinho e em uva. Apesar de o vinho constituir uma matriz complexa, a técnica ESI-MS por inserção direta permitiu quantificar os compostos polares majoritários tais como ácido málico, ácido tartárico e ácido cítrico. Nas uvas Vitis vinífera, Vitis labrusca e híbridos a análise de componentes principais (PCA) mostrou clara distinção entre vinhos de uvas diferentes e o agrupamento do vinho paulista com os vinhos da uva Syrah. O método ESI-MS por inserção direta está sendo proposto pela primeira vez para quantificação de ácidos em vinhos e uvas. O método aqui desenvolvido foi validado segundo as normas do Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMETRO) / Abstract: Varieties of grapes from the Vitis vinifera group incluind the Syrah grape are the most widely used for winemaking. A hybrid grape (Maximum-IAC 138-22) obtained by crossing Syrah and Seibel 11342 grapes has shown great adaptability in São Paulo State, producing apparently a high quality wine. This part first has compared the headspace aroma volatile composition of wine made from the Maximum IAC 138-22 grape with wines made from Syrah varietals originated from different regions of the world. Using static solid-phase microextration (SPME) followed by gas chromatography-mass spectrometry (GC-MS) analysis, main volatile compounds were identifield. Hierarchical clustering analysis (HCA) showed that the wine from the hybrid grape Maximum 138-22 has volatile aroma composition very similar to most high quality Syrah grape wines studied. In the second part the phenolic profile wine using the technique of electrospray ionization (ESI) coupled with mass spectrometry íon cyclotron resonance Fourier transform (FT-ICR MS) that allows detection of thousands of polar compounds in wine without chromatographic separation and simple sample preparation. Was found that the wine paulista has a profile similar phenolic other commercial wines from Syrah grapes. The ESI-MS technique for direct insertion allows us to obtain qualitative and quantitative results without chromatographic separation of wine. In the third and fourth studies employed the technique ESI-MS by direct insertion for quantifying organics acids in wine and grapes. As the wine is a complex matrix, pre concentration and filtration ESI-MS for direct insertion quantify the major polar compounds such as malic acid, tartaric acid and citric acid. In Vitis vinifera grape, Vitis labrusca and hybrid the principal component analysis (PCA) showed a clear distinction between wines from different grapes and wine group in São Paulo with wines from Syrah grapes. The ESI-MS method for direct insertion is first proposed for quantification of acids in wines and grapes. The method ESI-MS by direct insertion is first proposed for quantification acid in wines and grapes. The method developed here was validated according to the standards of the National Health Surveillance Agency and National Institute of Metrology, Quality and Technology (INMETRO) / Doutorado / Quimica Analitica / Doutora em Ciências
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Capacité photoprotectrices et anti-âge de quelques plantes halophytes du littoral Breton et de Tunisie / Photoprotective and anti-age capacities of some halophyte plants from the Breton coast and TunisiaJdey, Ahmed 19 September 2017 (has links)
Dans ce travail, l’évaluation des activités antioxydantes, antibactérienne, anti-âge et photoprotectrices ont été effectuées sur les parties aériennes de douze halophytes : dont 6 Tunisiennes et 6 françaises montre une variabilité importante en fonction de l’espèce.Cependant, la fraction MeoH60% se distingue par son activité antioxydante, antibactérienne ainsi que pour l’activité écran pour les deux plantes sélectionnées. Ensuite, les fractions MeOH20%, et MeOH40% présentent une activité anti-élastase et anti-collagénase importante pour Haloxylon articulatum alors que pour daucus carota les fractions MeOH20% et MeOH100% présentent les activités anti-élastase et anti-collagénase les plus intéressantes.L’évaluation du potentiel cytotoxique des fractions sur la viabilité des kératinocytes humains indique une absence de toxicité puisqu’une viabilité de 100% des cellules est obtenue avec différentes concentrations (jusqu’à 100 μg/ml) et différents temps de contact (jusqu’à 24 h) des deux plantes. Toutes les activités biologiques montrées dans cette étude sont expliquées par l'existence de divers composés phénoliques essentiellement: la scopolétine (coumarine aglycone), l’épigallocatéchine, l’esculétine et l’isorhamnétine triglycoside, l’acide caféique, l’acide chlorogénique, la lutéoline et sa forme glycosylé( la lutéoline-3-O-glucoside), enfin l’apigénine libre et sa forme glycosylée. / In this work, the evaluation of antioxidant, anti-bacterial, anti-aging and photoprotective activities was carried out on the aerial parts of twelve halophytes: 6 Tunisian and 6 French shows a high variability according to the species. A screening based on these activities allowed the selection of the two most promising species (Haloxylon articulatum and Daucus carota). A fractionation by adsorption chromatography of their hydroalcoholic extracts was used to specify its antioxidant, antimicrobial, anti-aging and cytotoxic capacities. The results show a high variability between the fractions. The MeOH20% and MeOH100% fractions showed the most interesting anti-elastase and anti-collagenase activities. The evaluation of the cytotoxic potential of the fractions on the viability of human keratinocytes indicates an absence of toxicity since a viability of 100% of the cells is obtained with different concentrations (up to 100 μg / ml) and different contact times (At 24 h) of the two plants.These biological activities were correlated to the presence of various phenolic compounds mainly: scopoletin (coumarin aglycone), epigallocatechin, esculetin , isorhametin triglycoside, caffeic acid, chlorogenic acid, Luteolin and its glycosylate form (luteolin-3-O-glucoside), and finally free apigenin and its glycosylate form.
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Étude de la décomposition de produits phytosanitaires par l'ozone : Application au traitement des semences déclassées / Study of the decomposition of pesticides by ozone : Application for the treatment of downgraded loaded seedsBourgin, Marc 11 January 2011 (has links)
Chaque année en France, les semenciers sont contraints de déclasser plus de 10 000 tonnes de semences. Ces semences sont actuellement incinérées dans des cimenteries au frais des semenciers et non valorisables dans des procédés de valorisation des agro-ressources, compte tenu de leur teneur non négligeable en pesticides. Par conséquent, il apparaît nécessaire de réduire, dans un premier temps, la quantité de produits phytosanitaires présents dans les enrobages avant de pouvoir valoriser ces semences déclassées.L’objet de cette thèse consiste donc à développer un outil permettant de décomposer une grande partie des produits phytosanitaires présents sur les enrobages par ozonation. Dans un premier temps, une méthode d’extraction par liquide pressurisé a été développée pour la quantification des produits phytosanitaires présents sur les enrobages avant et après ozonation. Cette méthode d’extraction a été validée et a permis de déterminer, par la suite,l’efficacité du traitement d’ozonation sur les semences enrobées.Ensuite, afin d’évaluer l’efficacité d’un traitement à l’ozone, deux pesticides présents dans la solution d’enrobage Gaucho Blé® -l’imidaclopride et le bitertanol- ont été ozonés, en solution aqueuse dans un réacteur agité. Les deux produits ont été dégradés complètement en moins de 30 minutes et la loi cinétique de leurs réactions d’ozonation a montré que l’ordre partiel de la réaction a été de 1 pour l’ozone et pour le pesticide. Les produits de dégradation,formés au cours de l’ozonation, ont aussi été analysés par spectrométrie de masse ESI(+)-MSet la structure de la plupart des produits de dégradation a été déterminée. Un schéma des différentes voies de dégradation de l’imidaclopride et du bitertanol a pu être proposé.Enfin, l’ozonation des pesticides a été étudiée sur les semences de blé tendre enrobées avec la solution de Gaucho Blé® dans un réacteur à lit fixe. L’humidification des grains avant ozonation, la concentration en ozone dans le gaz et la durée de traitement ont semblé être les facteurs importants pour accélérer la cinétique de dégradation des pesticides dans les enrobages. Les pesticides ont été dégradés (respectivement 99 et 90 % de dégradation pour l’imidaclopride et le bitertanol). La loi cinétique de la réaction d’ozonation de l’imidaclopride et du bitertanol a présenté des ordres partiels égaux à 1 pour l’ozone et pour le pesticide. Ce procédé a ensuite été appliqué à d’autres types de semences enrobées et s’est avéré efficace sur tous les principes actifs étudiés. Enfin, les semences enrobées ont été ozonées dans un réacteur prototype (réacteur à plateau vibrant) dans lequel tous les pesticides étudiés ont été dégradés mais à des taux de dégradation plus faibles qu’en réacteur à lit fixe. / Every year in France, seed producers must downgrade more than 10,000 tons of seeds. These seeds are currently incinerated in cement factories at seed producers’ expenses and non available for the processes of valorization of renewable resources, due to their significant pesticide content. Consequently, in the first step, the quantity of pesticides present in the seed loading must be reduced before a subsequent valorization of the downgraded seeds. The purpose of this PhD work is thus to develop a process for the decomposition of a large amount of the pesticides present in the seed loading. First, an extraction procedure by pressurized liquid was developed for the quantitation of phytopharmaceuticals present on the loading before and after the ozonation. This extraction method was validated and enabled to determine, subsequently, the efficiency of the ozonation process on the loaded seeds. In the second time, in order to evaluate the efficiency of an ozonation treatment, both pesticides present in the Gaucho Blé® seed loading solution – imidacloprid and bitertanol – were ozonated, in aqueous solutions in a stirred reactor. Both compounds were completely decomposed in 30 minutes and the kinetic law for the ozonation of both compounds displayed a partial order of 1 for ozone and 1 for the pesticide. Degradation products, formed during the ozonation, were analyzed by mass spectrometry ESI(+)-MS and the structure of most of the compounds was characterized. Degradation pathways for imidacloprid and bitertanol were thus proposed. Finally, the ozonation of pesticides were applied to soft wheat seeds loaded with Gaucho Blé® loading solution, in a fixed bed reactor. The humidification of seeds before ozonation, the concentration of ozone in the inlet gas and the ozonation time were the predominant factors to accelerate the kinetic of degradation of pesticides in the seed loadings. The pesticides were successfully decomposed (respectively 99 and 90 % for the degradation of imidacloprid and bitertanol). The kinetic laws for the ozonation reactions of imidacloprid and bitertanol were determined and the partial orders of the reaction were 1 for both ozone and the pesticide. This process was then applied to the treatment of other loaded seeds and showed good degradation rates for all the studied pesticides. Subsequently, the loaded seeds were ozonated in a prototype reactor equipped with a dynamic plate in which all the pesticides were decomposed but with lower degradation rates than in a fixed bed reactor.
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Emergency Department Triage Prediction of Emergency Severity Index using Machine Learning Models / Akutmottagningens förutsägelse av Emergency Severity Index med hjälp av MaskininlärningsmodellerSekandari, Zohib, Saleh, Shahin January 2019 (has links)
Study Objective: The emergency department (ED) in the United States strongly rely on subjective assessment of patients. This study seeks to evaluate an electronic triage system based on machine learning models that can predict the patients emergency severity index (ESI). Methods: A dataset containing 560 486 patients triage data was investigated.Three different machine learning models was tested and evaluated. A crossvalidation table and a confusion matrix was conducted from each of the models. The precision rate, recall rate and f1-score were calculated and reported. Result: The Gradient Boosting model returned an accuracy rate of 68%. The random forest model returned an accuracy rate of 66%. The Gaussian Naive Bayesmodel returned an accuracy rate of 25%. Conclusion: The model that best predicted the ESI-level is the GradientBoosting model. Further testing is needed with better computational power since we could not train our model with the whole dataset. / Syfte: Akutmottagningen i USA förlitar sig kraftigt på en subjektiv värdering av patienter. Denna studie söker efter att evaluera ett elektronisk triage systembaserad på maskininlärningsmodeller som kan förutse patienters ESI. Metod: Ett data set som innehåller 560 486 patienters triage data har undersökts. Tre olika maskininlärningsmodeller har testats och evaluerats. En cross validation tabell och en confusion matrix har skapats för varje modell. Precision, recall och f1 värde har kalkylerats och rapporterats. Resultat: Gradient Boosting modellen har returnerat ett accuracy värde av 68%. Random Forest modellen har returnerat ett accuracy värde av 66%. Gaussian Naive Bayes modellen har returnerat ett accuracy värde av 25%. Slutsats: Modellen som har bäst förutsett ESI nivåerna är Gradient Boostingmodellen. Flera tester behövs med starkare beräkningskraft då vi inte kunde träna vår modell med hela datasetet.
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Association and Fragmentation Characteristics of Biomolecules and Polymers Studied by Mass SpectrometryRivera-Tirado, Edgardo January 2007 (has links)
No description available.
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