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Avaliação da inervação entérica e análise proteômica do intestino delgado de ratos expostos à dose aguda ou crônica de fluoreto / Evaluation of enteric innervation and proteomic analysis of the small intestine of rats exposed to acute or chronic fluoride doseCarina Guimarães de Souza Melo 03 December 2015 (has links)
O trato gastrointestinal (TGI) é a principal rota de exposição ao fluoreto (F) e o seu mais importante sítio de absorção. Acredita-se que a toxicidade do F comprometa a fisiologia do intestino, devido à relevante sintomatologia gastrointestinal relatada em consequência da exposição excessiva ao F. A função intestinal é controlada por uma complexa rede neuronal interligada e incorporada à parede deste órgão, denominada Sistema Nervoso Entérico (SNE). Embora os efeitos tóxicos do F sobre o Sistema Nervoso Central sejam descritos na literatura, não há estudos relacionados à sua toxicidade sobre o SNE. Neste estudo realizado em ratos, foi avaliado o efeito da exposição aguda ou crônica ao F, sobre a população geral de neurônios entéricos e sobre as subpopulações que expressam os principais neurotransmissores entéricos: Acetilcolina (ACh), Óxido Nítrico (NO), Peptídeo Vasoativo Intestinal (VIP), Peptídeo Relacionado ao Gene da Calcitonina (CGRP) e Substância P (SP). Os animais foram divididos em 5 grupos: 3 destinados à exposição crônica (0 ppm, 10 ppm ou 50 ppm de F na água de beber) e 2 à exposição aguda (0 ou 25 mgF/Kg por gavagem gástrica). Foram coletados os 3 segmentos do intestino delgado (duodeno, jejuno e íleo) e processados para a detecção da HuC/D, ChAT, nNOS, VIP, CGRP e SP, através de técnicas de imunofluorescência, no plexo mioentérico. Foram obtidas imagens para a realização da análise quantitativa dos neurônios da população geral (HuC/D) e nitrérgicos (imunorreativos à nNOS); e morfométrica dos neurônios imunorreativos à HuC/D ou nNOS; e das varicosidades imunorreativas à ChAT, VIP, CGRP ou SP. Amostras dos 3 segmentos intestinais foram preparadas e coradas em Hematoxilina e Eosina para análise histológica da morfologia básica. O segmento intestinal considerado mais afetado na análise morfométrica da população geral de neurônios, o duodeno, foi selecionado para a realização da análise proteômica, com o objetivo de oferecer o seu perfil proteico e determinar diferenças na expressão proteica em decorrência da exposição crônica ou aguda ao F. A análise da concentração de F no plasma sanguíneo foi realizada para a confirmação da exposição. Na análise quantitativa, o grupo de 50 ppm F, apresentou uma diminuição significativa na densidade da população geral de neurônios do jejuno e do íleo e na densidade dos neurônios imunorreativos à nNOS no duodeno e no jejuno. Quanto à análise morfométrica, a população geral e as subpopulações neuronais entéricas avaliadas apresentaram alterações morfológicas significativas, tanto após a exposição crônica quanto a aguda. Para a análise proteômica do duodeno, verificou-se que da associação de seus genes a um termo, e assim classificadas de acordo com diferentes processos biológicos. No caso do grupo da dose aguda, o processo biológico com a maior porcentagem de genes associados foi a geração de metabólitos precursores e energia (27% das proteínas); enquanto para os grupos de 10 e 50 ppm F foram o processo metabólico da piridina (41%) e a polimerização proteica (33%), respectivamente. / The gastrointestinal tract (GIT) is the main route of fluoride (F) exposure, and the most important site of its absorption. It is believed that F toxicity compromises the intestine physiology, due to the relevant gastrointestinal symptomatology reported in consequence to excessive exposure. The intestinal function is controlled by a complex neuronal net, which is interconnected and embedded in the wall of this organ, named Enteric Nervous System (ENS). Although the toxic effects of F on the Central Nervous system are described in the literature, there are no studies related to its toxicity on the ENS. Therefore, in this study performed in rats, the effects of chronic and acute F exposure were evaluated, on the general population of enteric neurons and on the subpopulations that express the main enteric neurotransmitters: Acetylcholine (Ach), Nitric Oxide (NO), Vasoactive Intestinal Peptide (VIP), Calcitonin gene related peptide (CGRP), and Substance P (SP). The animals were divided into 5 groups: 3 designed to the chronic exposure (0 ppm, 10 ppm ou 50 ppm de F in the drinking water) and 2 to the acute exposure (0 ou 25 mgF/Kg - gastric gavage). Three intestinal segments were collected (duodenum, jejunum, and ileum) and processed for the immunofluorescence techniques to detect HuC/D, ChAT, nNOS, VIP, CGRP and SP, on the myenteric plexus. Images were obtained for the quantitative analysis of the general population of neurons (HuC/D immunoreactive) and the nitrergic neurons (nNOS immunoreactive), for the morphometric analysis of the general population and nitrergic neurons and also for the immunoreactive varicosities to ChAT, VIP, CGRP or SP. Samples of the 3 intestinal segments were prepared and stained with hematoxylin and eosin for histological analysis of the basic morphology. Duodenum, the intestinal segment considered the most affected in the morphological analysis of the general population of neurons, was selected for the proteomic analysis, with the objective to offer the entire protein profile and to determine differences in the protein expression due to chronic or acute F exposure. Plasma F concentration was analyzed to confirm the exposure. In the quantitative analysis, the 50 ppm F group presented a significant decrease in the density of the general population of neurons in the jejunum and ileum, and in the density of the nitrergic neurons in the duodenum and jejunum. Regarding the morphometric analysis, the general population of neurons and all the neuronal subpopulations evaluated presented significant morphological alterations, for both exposures, chronic and acute. In the proteomic analysis of the duodenum, it was verified that both exposures caused alterations in the expression of intestinal proteins. These proteins identified with differential expression were distributed according the association of their genes to a specific term, and by this term classified in different biological process. In the group that received the acute dose the biological process with the highest percentage of associated genes was the generation of precursor metabolites and energy (27% of proteins), and for the 10 and 50 ppm F groups, they were pyridine nucleotide metabolic process (41%) and protein polymerization (33%), respectively.
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Avaliação da efetividade da escovação supervisionada com dentifrício fluoretado na promoção de saúde bucal em escolares residentes em comunidades ribeirinhas do Estado do AmazonasSilva, Franklin Barbosa da 21 August 2014 (has links)
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Previous issue date: 2014-08-21 / CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / The objective of this study was to evaluate the effectiveness of a program to promote oral health on caries control of adolescents in riverine communities in the Amazonas State. This is a prospective longitudinal experimental study, whose interventions were allocated for population groups (schools) and the outcome was measured at the individual level. The test interventions were based: education for oral health and daily tooth brushing with fluoride toothpaste, supervised by teachers on a school routine. The control intervention included oral health education and periodic distribution of toothbrushes and fluoride toothpaste. The schools were divided into test and control groups, and the data were collected before (baseline) and six months after the beginning of the interventions. There were included students in the age group of 15 to 19 years enrolled in state schools in the city of Careiro da Várzea / AM. For outcome evaluation, the clinical variables collected were: Nyvad criteria for caries activity evaluation, bleeding index and plaque index; being complemented by a socioeconomic questionnaire. Clinical examination and data collection were performed by a previously calibrated dentist [Kappa Coefficient for Nyvad criteria: k = 0.72 (95% CI: 0.69 to 0.76)]. The associations between the outcome (caries activity) and clinical and socioeconomic variables were tested in multivariate logistic regression, estimating the brute and adjusted odds ratio. After six months of interventions, 51.7% of the non-cavitated active lesions in the test group and 37.8% of these lesions in the control group became inactive or health surfaces. Individuals in the control group had 1.93 (95% CI: 1.07 to 3.49) more chance to have no improvement in caries activity than the individuals in the test group (p=0.0289). Demonstrating that daily supervised brushing with fluoride toothpaste (test intervention) was more effective than the simple distribution of toothbrushes and fluoride toothpaste (control intervention) in the caries control. / O objetivo deste trabalho foi avaliar a efetividade de um programa de promoção de saúde bucal, no controle da cárie em adolescentes de comunidades ribeirinhas no Estado do Amazonas. Trata-se de um estudo experimental longitudinal prospectivo, cujas intervenções foram alocadas para grupos populacionais (escolas) e o desfecho foi mensurado no nível individual. A intervenção teste teve como base: educação para saúde bucal e escovação diária com dentifrício fluoretado, supervisionada por professores, numa rotina escolar. A intervenção controle incluiu: educação para saúde bucal e distribuição periódica de escovas e dentifrício fluoretado. As escolas foram alocadas em grupos teste e controle, e os dados foram coletados antes (baseline) e seis meses após o início das intervenções. Foram incluídos alunos na faixa etária de 15 a 19 anos regularmente matriculados nas escolas estaduais do Município de Careiro da Várzea/AM. Para avaliação do desfecho, as variáveis clínicas coletadas foram: critério Nyvad para avaliação da atividade de cárie, índice de sangramento gengival e índice de placa; sendo complementadas com o preenchimento de questionário socioeconômico. Os exames clínicos e a coleta dos dados foram realizados por um cirurgião-dentista calibrado previamente [Coeficiente Kappa para o critério Nyvad: k=0.72 (IC95%: 0,69-0,76)]. As associações entre o desfecho (atividade de cárie) e as variáveis clínicas e socioeconômicas foram testadas na análise de regressão logística múltipla, estimando-se os odds ratio, brutos e ajustados. Após seis meses de intervenção, 51,7% das lesões não cavitadas ativas no grupo teste, e 37,8% destas lesões no grupo controle, se tornaram inativas ou superfícies sadias. Os indivíduos do grupo controle apresentaram 1,93 (IC95%: 1,07-3,49) vezes mais chance de não melhora, para a atividade de cárie, que os indivíduos do grupo teste (p=0,0289), demonstrando que a escovação supervisionada diária com dentifrício fluoretado (intervenção teste) foi mais efetiva que a simples distribuição de escovas e de dentifrícios fluoretados (intervenção controle) no controle da doença cárie.
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Comparação do potencial erosivo de duas fontes ácidas sobre o esmalte e avaliação de métodos de controle da erosão dental / Comparison of the erosive potential of two acidic sources in enamel and evaluation of treatments for prevention of dental erosionSheila Regina Maia Braga 01 September 2009 (has links)
Erosão dental é definida como a perda irreversível de tecido duro dental por um processo químico que não envolve bactérias. O objetivo deste trabalho foi comparar in vitro o potencial erosivo de duas fontes ácidas e avaliar métodos de controle da erosão dental em esmalte. Para a comparação das fontes ácidas, coroas de 5 molares inclusos foram seccionadas em quatro, totalizando 20 espécimes. Nos espécimes, uma superfície de esmalte (janela) de 3 x 3 mm foi delimitada. Os espécimes foram submetidos ao desafio erosivo em suco gástrico (obtido durante endoscopia) (n=10), ou suco de laranja (industrializado) (n=10), como segue: 5 minutos em 3 ml de solução ácida, enxágue com água destilada e armazenagem em saliva artificial por 3 horas. Este ciclo foi repetido 4 vezes ao dia por 14 dias. O cálcio (Ca) eliminado dos espécimes na solução ácida foi quantificado por Espectrometria de emissão atômica. A presença de carbonato (CO) e fosfato (PO) foi avaliada nos espécimes antes e após o desafio erosivo pela Espectroscopia FT-Raman. Para a avaliação dos métodos de controle da erosão quarenta espécimes de esmalte de molares inclusos foram distribuídos para cada um dos métodos propostos (n=10): gel de flúor fosfato acidulado (APF 1,23%), laser de Nd:YAG (100 mJ, 1 W, 10 Hz), associação flúor + laser e laser + flúor. Os métodos de controle foram aplicados 1 hora antes do desafio erosivo já descrito, realizado com ácido clorídrico (0,01 M/pH 2,2) como fonte ácida. O flúor foi mantido por 4 minutos sobre a superfície de esmalte. A superfície foi irradiada, com contato, após aplicação de um fotoabsorvedor. As associações foram feitas utilizando o flúor e o laser como descrito anteriormente. A perda de Ca dos espécimes foi quantificada por Espectrometria de emissão atômica e a rugosidade superficial dos espécimes (Ra) foi avaliada antes e após o desafio erosivo. Na comparação das fontes ácidas, os espécimes submetidos à erosão perderam: 12,74 ± 3,33 mg/L de Ca (suco gástrico) e 7,07 ± 1,44 mg/L de Ca (suco de laranja) (p=0,0003). A análise em Espectroscopia FT-Raman não detectou alteração significativa na razão CO/PO após o desafio ácido. Os valores CO/PO antes e depois do desafio foram: 0,16/0,17 (suco gástrico) (p=0,37) e 0,18/0,14 (suco de laranja) (p=0,16). Na avaliação dos métodos de controle da erosão, as perdas de Ca foram (mg/L): APF 1,707a (± 0,113), Nd:YAG 1,638a (±0,080), APF + Nd:YAG 1,385b (±0,078), Nd:YAG + APF 1,484b (±0,068). A rugosidade média inicial dos espécimes foi de 0,14 m. Após o desafio erosivo a rugosidade apresentou significativo aumento (p<0,01): APF 0,69bc (±0,091), Nd:YAG 0,87a (±0,119), APF + Nd:YAG 0,61c (±0,090) e Nd:YAG + APF 0,72b (±0,069). Foi possível concluir que o suco gástrico apresentou potencial erosivo ao esmalte maior que o suco de laranja. A associação entre flúor e laser apresentou-se mais eficaz no controle da erosão dental do que os métodos isoladamente. / Dental erosion is defined as irreversible loss of dental hard tissue due to chemical processes without the involvement of microorganisms. The aim of this study was to compare in vitro the erosive potential of two acidic sources and evaluate the effectiveness of treatments for prevention of dental erosion. To compare the acidic sources, crowns of 5 unerupted human third molars were sectioned in four, totalizing 20 enamel slabs. In the slabs, a test surface (window) of 3 x 3 mm was delimited. The specimens were submitted to erosive challenge into gastric juice (from endoscopy exam) (n=10), or orange juice (industrialized) (n=10), as follows: 5 minutes in 3 ml of acidic solution, rinse with distilled water and stored in artificial saliva for 3 hours. This cycle was repeated for four times a day during 14 days. Calcium (Ca) loss after acid exposure was determined by atomic emission spectroscopy. The presence of carbonate (CO) and phosphate (PO) in the specimens was evaluated before and after the erosive challenge by FT-Raman spectroscopy. To evaluate the treatments for prevention of dental erosion, forty enamel specimens of unerupted human third molars were distributed according to the following treatments (n=10): acidic phosphate fluoride gel (APF 1.23%), Nd:YAG laser (100 mJ, 1 W, 10 Hz), and the associations fluoride + laser and laser + fluoride. These treatments were applied 1 hour before the erosive challenge, which, in this phase was made with hydrochloric acid only (0.01 M/pH 2.2). The fluoride was applied on the enamel surfaces for 4 minutes. The irradiation of enamel surface was made in the contact mode after coating with a photo-activator. The associations were done using fluoride and laser like describe before. The Ca loss was determined by atomic emission spectroscopy and superficial roughness (Ra) was measured before and after the erosive challenge. In the comparison of the acidic sources, the mean loss of Ca were: 12.74 ± 3.33 mg/L Ca (gastric juice) and 7.07 ± 1.44 mg/L Ca (orange juice) (p=0.0003). The FT-Raman spectroscopy found no statistically significant difference in the ratio CO/PO after the erosive challenge. The CO/PO ratios values before and after the challenge were: 0.16/0.17 (gastric juice) (p=0.37) and 0.18/0.14 (orange juice) (p=0.16). In the evaluation of the treatments, the mean Ca loss were (mg/L): APF 1.707a (± 0.113), Nd:YAG 1.638a (±0.080), APF + Nd:YAG 1.385b (±0.078), Nd:YAG + APF 1.484b (±0.068). The mean initial roughness of specimens was 0.14 m. After the erosive challenge the roughness showed a significant increase (p<0.01): APF 0.69bc (±0.091), Nd:YAG 0.87a (±0.119), APF + Nd:YAG 0.61c (±0.090) and Nd:YAG + APF 0.72b (±0.069). It was concluded that gastric juice has higher erosive potential to enamel than orange juice and the association between fluoride and laser was more efficient for the prevention of dental erosion than both methods separately.
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Avaliação de novos tratamentos preventivos da erosão e abrasão do esmalte e da dentina / Evaluation of new preventive treatments for erosion and abrasion of enamel and dentinCintia Maria de Souza e Silva 26 July 2013 (has links)
Este trabalho, conduzido na forma de 2 subprojetos, avaliou: 1) o potencial preventivo de pastas à base de hidroxiapatita (nanopartículas de fosfato de cálcio) sobre a erosão e a abrasão do esmalte e dentina bovinos in vitro e in situ e 2) o efeito de um bochecho com solução de lactato de cálcio antes da escovação com dentifrício fluoretado sobre a erosão associada ou não à abrasão do esmalte e dentina bovinos in vitro e in situ. Na fase in vitro do 1o subprojeto, submeteram-se blocos de esmalte e dentina bovinos, por 5 dias, à erosão (coca-cola, pH 2,6, 4x/dia, 90s cada) + abrasão (escova elétrica + solução do dentifrício sem flúor, 10s cada, 2x/dia) e os tratamentos foram realizados após a abrasão, através da aplicação das seguintes pastas sobre os blocos (3 min, 2x/dia): 10% HAP, 10% HAP + 0,2% NaF, 20% HAP, 20% HAP + 0,2% NaF, 20% HAP + 2% NaF, placebo, 0,2% NaF, 2% NaF, MI paste, MI paste plus e controle. Na fase in situ, (4 fases, 5 dias/cada), 12 voluntários utilizaram dispositivo intrabucal palatino contendo 4 blocos de dentina e 4 de esmalte bovinos divididos nas condições: erosão e erosão+abrasão. Em cada fase foi feito tratamento com uma das seguintes pastas: 10% HAP, 10% HAP + 0,2% NaF, MI paste plus ou Placebo. O protocolo erosivo e abrasivo foi semelhante ao in vitro. No 2o subprojeto, a fase in vitro foi semelhante ao subprojeto 1, porém apresentou as condições erosão e erosão+abrasão. O estudo compreendeu os seguintes tratamentos: BCa + DF, BCa + DP, BP + DF e BP + DP. Após erosão, os blocos foram imersos em água deionizada (BP) ou solução de lactato de cálcio 150 mM (BCa; 1 min, sob agitação). Na condição erosão apenas, a solução de dentifrício fluoretado (DF) ou placebo (DP) foi pipetada sobre as amostras. A fase in situ foi semelhante ao experimento in vitro, porém com 15 voluntários e escovação por 15 s. A variável de resposta para os 2 subprojetos foi a análise de desgaste, avaliada por perfilometria (μm) e para a fase in situ do 1o subprojeto foi realizada também a análise por MEV-EDS. Os dados foram analisados pelos testes ANOVA/Tukey, Kruskal-Wallis/Dunn ou ANOVA a dois critérios/Bonferroni (p<0,05). In vitro, para o esmalte, as pastas à base de hidroxiapatita (10 e 20%), independentemente da presença do F, foram efetivas na prevenção da erosão associada à abrasão. Para a dentina, o efeito protetor foi encontrado apenas para as pastas contendo F, maior para aquelas com concentração mais elevada. In situ, apenas a pasta contendo 10% HAP foi efetiva para reduzir a erosão em esmalte quando comparada à pasta placebo. Nas demais condições testadas nenhuma das pastas utilizadas diferiu significativamente da placebo. Para o segundo subprojeto, o BCa + DF teve um efeito protetor apenas para a erosão de esmalte e dentina in vitro. Para a erosão associada à abrasão in vitro, assim como no estudo in situ, não houve diferença significativa entre os tratamentos. / This study, conducted in the form of two subprojects, evaluated: 1) the preventive potential of hydroxyapatite-based (calcium phosphate nanoparticles) pastes on erosion and abrasion of bovine enamel and dentin in vitro e in situ and 2) the effect of rinsing with a solution of calcium lactate before brushing with fluoride toothpaste on erosion associated or not with abrasion of bovine enamel and dentin in vitro e in situ. In the in vitro phase of the 1st subproject, bovine enamel and dentin blocks were submitted to erosion (coca-cola, pH 2.6, 4x/day, 90s each) + abrasion (electric toothbrush + fluoride-free toothpaste slurry, 10s each, 2x/day) for 5 days. Treatments were performed after abrasion, by applying the following pastes on the blocks (3 min, 2x/day): 10% HAP, 10% HAP + 0.2% NaF, 20% HAP, 20% HAP + 0.2% NaF, 20% HAP + 2% NaF, placebo, 0.2% NaF, 2% NaF, MI paste, MI paste plus and control. In the in situ phase (4 phases, 5 days each), 12 volunteers used intraoral palatal appliance containing four blocks of dentin and four blocks enamel divided into conditions erosion and erosion+abrasion. In each phase, treatment was done with one of the following pastes: 10% HAP, 10% HAP + 0.2% NaF, MI paste plus or Placebo. The erosive and abrasive protocol was similar to the in vitro phase. In the 2nd subproject, the in vitro phase was similar to subproject 1, but presented both conditions erosion and erosion + abrasion. The study included the following treatments: BCa + DF, BCa + DP, BP + DF e BP + DP. After erosion, the blocks were immersed in deionized water (BP) or calcium lactate solution 150 mM (BCa; 1 min, stirring). For the condition erosion only, the slurry of fluoride (DF) or placebo (DP) dentifrice was pipetted on the samples. The in situ phase was similar to the in vitro experiment, but 15 volunteers were included and brushing was conducted for 15 s. The response variable for the two subprojects was wear, evaluated by profilometry (μm). For the in situ phase of the 1st subproject, SEM-EDS was also performed. Data were analyzed by ANOVA/Tukey, Kruskal-Wallis/Dunn or two-way ANOVA/Bonferroni tests (p <0.05). In vitro , for enamel, 10 and 20% hydroxyapatitebased pastes, regardless the presence of F, were effective in preventing erosion associated with abrasion. For dentin, the protective effect was found only for Fcontaining paste and the effect was higher for those with higher F concentration. In situ, only pastes containing 10% HAP were effective in reducing enamel erosion as compared to the placebo paste. For the other tested conditions, none of the pastes used significantly differed from placebo. For the second subproject, the BCa + DF had a protective effect only for enamel and dentin erosion in vitro . For erosion associated with abrasion in vitro , as well as for the in situ study, no significant differences were detected among the treatments.
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Ionômero de vidro resinoso nanoparticulado: avaliação de propriedades físico-químicas e biológicas / Resin modified nano ionomer: physical-chemical and biological evaluationEdélcio Garcia Júnior 15 October 2009 (has links)
O objetivo deste estudo foi avaliar o cimento de ionômero de vidro modificado por resina de nanopartículas Ketac™N100, por meio de três metodologias diferentes: resposta tecidual em subcutâneo de camundongos isogênicos, liberação de flúor e tensão de contração de polimerização, in vitro. Foram utilizados 90 camundongos isogênicos da linhagem BALB/c, divididos em 9 grupos (n=10), nos quais foram implantados tubos de polietileno contendo o Ketac™ 100, ChemFilR (ionômero de vidro convencional) ou tubo vazio. Nos períodos experimentais de 7, 21 e 63 dias o tubo e o tecido adjacente foram removidos para análise microscópica. Para o ensaio de avaliação da tensão de contração de polimerização, foram utilizados dois bastões de vidro fixados a uma máquina de ensaio universal. Nos bastões foi acoplado um extensômetro para medição da força de contração de polimerização de cinco materiais (Resina Filtek™Z350, CompoglassR F, VitremerMR, Ketac™N100 e ChemFilR), com 10 corpos de prova para cada material. Para o ensaio de liberação de flúor, foram confeccionados 8 corpos de prova de 3 diferentes materiais (Ketac™ 100, Vidrion R e Resina Filtek™ Z250), colocados individualmente em 1 ml de saliva artificial. O corpo de prova foi trocado a cada dia por 15 dias e a solução obtida utilizada para a leitura do íon fluoreto.Os resultados microscópicos evidenciaram que a inflamação presente na abertura dos tubos, aos 7 dias, sofreu uma diminuição em área e espessura até os 63 dias, nos 2 materiais e no grupo controle. Comparando a área da reação inflamatória o Ketac™N100 foi diferente estatisticamente do ChemFilR, nos períodos de 7 e 21 dias (p>0,05), com uma área menor para o Ketac™N100. A espessura da reação inflamatória nos períodos de 7 e 21 dias apresentou valores semelhantes entre o Ketac™N100 e ChemFilR (p>0,05). Aos 63 dias, os valores foram estatisticamente diferentes, com um pequeno aumento de espessura para o Ketac™N100. Os valores de tensão de contração de polimerização obtidos seguiram a seguinte ordem crescente: ChemFilR < VitremerMR < Ketac™N100 < CompoglassR F ~ Filtek™Z350 (p>0,05). Quando comparados dois a dois, o ionômero modificado por resina de nanopartículas Ketac™N100 se aproximou mais dos valores da resina Filtek™ Z350 (p>0,05) do que do ionômero de vidro convencional ChemFilR (p<0,05). A sua liberação de flúor ocorreu mais significativamente nos dois primeiros dias, com valores médios 33% menores em comparação ao Vidrion R. Concluímos que o ionômero resinoso nanoparticulado Ketac™N100 é um material que induz uma resposta inflamatória tecidual satisfatória em subcutâneo de camundongos isogênicos. Sua contração de polimerização foi menor do que de a resina Filtek™ Z350 e a liberação de flúor foi um terço menor do que a dos ionômeros convencionais. / The aim of this study was to evaluate the resin modified nano ionomer Ketac™N100, by three different methodologies: tissue response in of isogenic mice subcutaneous, fluoride release and shrinkage stress of polymerization in vitro. We used 90 isogenic mice (BALB / c), divided into 9 groups (n = 10), which were implanted with polyethylene tubes containing Ketac™ 100, ChemFilR (Ionomer conventional) or empty tube. In the experimental periods of 7, 21 and 63 days the tube and the surrounding tissue were removed for microscopic analysis. To evaluating the stress of contraction of polymerization, we used two glass rods attached to a universal testing machine. In the rods was attached to an extensometer to obtain the measure of the polymerization shrinkage strength of five materials (resin Filtek™Z350, CompoglassR F, VitremerMR F, Ketac™ 100 and ChemFilR), with 10 specimens for each material. In the fluoride release test, 8 specimens of 3 different materials (Ketac™ 100, Vidrion R and Resin Filtek™ Z250) placed individually in 1 ml of artificial saliva. The specimens were changed each day for 15 days and we use this solution used for reading the fluoride ion. The microscopic results showed that the inflammation in the opening of the tubes at 7 days decreased in area and thickness up to 63 days in 2 materials and the control group. Comparing the inflammatory reaction area, Ketac™N100 was statistically different from ChemFilR, in periods of 7 and 21 days (p> 0.05), with a smaller area for Ketac™N100. The inflammatory reaction in the periods of 7 and 21 days showed similar values between the Ketac™N100 and ChemFilR (p> 0.05). At 63 days, the values were statistically different, with a small increase in thickness to Ketac™N100. The values of polymerization shrinkage strength obtained after polymerization followed this ascending order: ChemFilR < VitremerMR F < Ketac™ 100 < CompoglassR F ~ Filtek™Z350 (p> 0.05). When compared two by two, the resin modified nano ionomer Ketac™N100 approached most of the values of resin Filtek™ Z350(p> 0.05) than the conventional glass Ionomer ChemFilR (p <0.05). The fluoride release occurred more significantly in the first two days, with average 33% lower compared with Vidrion R. We conclude that the resin modified nano ionomer Ketac™N100 is a material that induces an satisfactory inflammatory response in subcutaneous tissue of isogenic mice. Its polymerization shrinkage strength was lower than the resin Filtek™ Z350 and fluoride release was a third lower than the conventional glass ionomer.
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Diode-Pumped High-Energy Laser Amplifiers for Ultrashort Laser Pulses The PENELOPE Laser SystemLöser, Markus 23 January 2018 (has links) (PDF)
The ultrashort chirped pulse amplification (CPA) laser technology opens the path to high intensities of 10^21 W/cm² and above in the laser focus. Such intensities allow laser-matter interaction in the relativistic intensity regime. Direct diode-pumped ultrashort solid-state lasers combine high-energy, high-power and efficient amplification together, which are the main advantages compared to flashlamp-pumped high-energy laser systems based on titanium-doped sapphire. Development within recent years in the field of laser diodes makes them more and more attractive in terms of total costs, compactness and lifetime.
This work is dedicated to the Petawatt, ENergy-Efficient Laser for Optical Plasma Experiments (PENELOPE) project, a fully and directly diode-pumped laser system under development at the Helmholtz–Zentrum Dresden – Rossendorf (HZDR), aiming at 150 fs long pulses with energies of up to 150 J at repetition rates of up to 1 Hz. The focus of this thesis lies on the spectral and width manipulation of the front-end amplifiers, trivalent ytterbium-doped calcium fluoride (Yb3+:CaF2) as gain material as well as the pump source for the final two main amplifiers of the PENELOPE laser system. Here, all crucial design parameters were investigated and a further successful scaling of the laser system to its target values was shown.
Gain narrowing is the dominant process for spectral bandwidth reduction during the amplification at the high-gain front-end amplifiers. Active or passive spectral gain control
filter can be used to counteract this effect. A pulse duration of 121 fs was achieved by using a passive spectral attenuation inside a regenerative amplifier, which corresponds to an improvement by a factor of almost 2 compared to the start of this work. A proof-of-concept experiment showed the capability of the pre-shaping approach. A spectral bandwidth of 20nm was transferred through the first multipass amplifier at a total gain of 300. Finally, the predicted output spectrum calculated by a numerical model of the final amplifier stages was in a good agreement with the experimental results.
The spectroscopic properties of Yb3+:CaF2 matches the constraints for ultrashort laser pulse amplification and direct diode pumping. Pumping close to the zero phonon line at 976nm is preferable compared to 940nm as the pump intensity saturation is significantly lower. A broad gain cross section of up to 50nm is achievable for typical inversion levels. Furthermore, moderate cryogenic temperatures (above 200K) can be used to improve the amplification performance of Yb3+:CaF2. The optical quality of the doped crystals currently available on the market is sufficient to build amplifiers in the hundred joule range.
The designed pump source for the last two amplifiers is based on two side pumping in a double pass configuration. However, this concept requires the necessity of brightness conservation for the installed laser diodes. Therefore, a fully relay imaging setup (4f optical system) along the optical path from the stacks to the gain material including the global beam homogenization was developed in a novel approach.
Beside these major parts the amplifier architecture and relay imaging telescopes as well as temporal intensity contrast (TIC) was investigated. An all reflective concept for the relay imaging amplifiers and telescopes was selected, which results in several advantages especially an achromatic behavior and low B-Integral. The TIC of the front-end was improved, as the pre- and postpulses due to the plane-parallel active-mirror was eliminated by wedging the gain medium.
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Accumulateur lithium-ion à cathode de fluorures de métaux de transition / Transition metal fluoride for lithium-ion batteries applicationsDelbegue, Diane 25 September 2017 (has links)
Les batteries lithium ions sont la technologie de référence pour le stockage électrochimique de l’énergie. Cependant, les matériaux cathodiques de ces batteries comme LiCoO2, LiMn2O4 ou LiFePO4 présentent une capacité spécifique limitée (<160 mAh/g). De nombreux composés sont à l’étude pour améliorer cette performance dont le fluorure de fer (III) en raison de sa capacité théorique de 711 mAh.g-1. Ce travail présentera la synthèse de FeF3 par différentes méthodes de fluoration. Les matériaux obtenus seront comparés en termes de structures et de liaison (DRX, Mössbauer, spectroscopies IR et Raman) mais aussi de texture (isothermes d’adsorption à l’azote à 77K). Les propriétés électrochimiques des matériaux obtenus seront également comparées et testées. Enfin, l’étude du mécanisme électrochimique de cette famille de composés sera menée via une méthode de caractérisation « in operando » : la spectroscopie d’absorption des rayons X (XAS). / The lithium-ion batteries are the current solution for electrochemical energy storage. However, their performances are limited by the cathode materials, such as LiCoO2, LiMn2O4 or LiFePO4 of specific capacity lower than 160 mAh/g. Many materials are good candidates to improve this capacity such as iron trifluoride of theoretical capacity of 711 mAh.g-1. This work will present the synthesis of FeF3 through different fluorination ways. The resulting materials will be characterized owing to their structure by XRD, Mössbauer, Raman and IR spectroscopies and their texture by nitrogen adsorption isotherms at 77K and SEM. After that, the electrochemical properties will be evaluated and compared. Finally, the study of the electrochemical mechanism of this family of compounds will be led with a method of characterization “in operando” : the X-rays absorption spectroscopy (XAS).
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Activation acide ou superacide : synthèse de nouveaux composés azotés fluorés et polycycliques / Acid or superacid activation : synthesis of new fluorinated and polycyclic nitogenous compoundsMetayer, Benoît 07 November 2014 (has links)
Le fluor est devenu un élément incontournable en chimie médicinale. Les propriétés physico-chimiques induites par l'incorporation de cet atome dans les composés organiques en font un outil efficace dans la conception de mimes de fonctions chimiques. Les difficultés pour accéder aux composés azotés fluorés permettent d'envisager l'utilisation des milieux superacides et acides fluorants comme alternative de synthèse.Dans la première partie, la réactivité de N-allyl-N-arylbenzènesulfonamides en milieu superacide HF / SbF5 a été étudiée. La non observation de la cyclisation de type Friedel-Craft intramoléculaire initialement envisagée pour ces composés a été expliquée grâce à une étude mécanistique utilisant la RMN basse température in situ. En modifiant les conditions opératoires, la synthèse de N-arylbenzènesulfonamides α-fluorés a pu être développée. Les structures obtenues ont été testées pour l'inhibition des anhydrases carboniques.Dans la seconde partie, une nouvelle réaction d'hydrofluoration d'ynamides dans le milieu HF / pyridine a été développée. Cette stratégie a permis d'obtenir régio- et stéréosélectivement des (E)-α-fluoroènamides originaux. Par analogie avec les fluoroalcènes décrits en tant que mimes d'amides, les α-fluoroènamides sont potentiellement des isostères de la fonction urée. Le biomimétisme de ces structures est discuté grâce aux résultats d'études structurales réalisées par modélisation moléculaire. La réactivité surprenante de structures ortho-substituées en milieu superacide a permis le développement d'une réaction de polycyclisation intramoléculaire d'ynamides, cette nouvelle méthode permettant d'accéder en une étape à des polycycles azotés à haute valeur ajoutée. / During the last decades, fluorine became an essential element in medicinal chemistry. The original physical and chemical properties induced by the incorporation of this atom in organic compounds led to the development of fluorinated compounds as bioisosters in medicinal chemistry. Difficulties to access to fluorinated nitrogen containing compounds by "classical methods" led to the use of superacid as an alternative for their synthesis.In the first part of this work, the reactivity of unsaturated N-arylbenzenesulfonamides in superacidic media HF / SbF5 was studied. Intramolecular cyclisation of Friedel-Craft type expected for these compounds was studied and explored through a mechanistic study based on in situ low temperature NMR experiments. By modifying the operating conditions, the synthesis of α-fluorinated N-arylbenzenesulfonamide compounds was developed. The synthetized structures were then tested for carbonic anhydrase inhibition.In a second part, a new hydrofluorination reaction of ynamides was developed, using fluorhydric acid / pyridine media. This strategy allowed to access regio- and stereoselectively to original (E)-α-fluoroenamides. By analogy with the described fluoroalkenes as peptid bond isosters, α-fluoroenamides could potentially be considered as urea bioisosters. The bioisosterism of these structures was discussed and evaluated by using molecular modelling. The surprising reactivity of ortho-substitued structures in superacid media allowed the development of an intramolecular polycyclisation reaction, offering a one step route to complex nitrogen containing molecular polycyclic motif.
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Development and Evaluation of an Aquifer Capability Screening Tool Pilot Study: Clarence-Rockland, OntarioMorton, Samuel R. January 2015 (has links)
Increased development pressure led the United Counties of Prescott and Russell to seek development of a GIS-based Aquifer Capability Screening Tool (ACST). A Pilot ACST, developed by a project partner within this study, was made for the City of Clarence-Rockland, Ontario, and consists of several maps showing delineated areas where there may be groundwater limitations in terms of quality or quantity. This study gathered the chemistry data needed for the Pilot ACST from 127 domestic dug and drilled wells. The results showed exceedances of provincial health and aesthetic standards, which were then used to delineate maps for the Pilot ACST. An evaluation of the necessary data source and sampling scale for ACST development revealed that data gathered from existing reports was inadequate for various reasons and sampling scale should be on a grid 2x2 km2 or smaller. Further recommendations were provided for future ACST development studies.
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Riskmoment vid släckning av brand i litium-jonbatterier ombord på fartyg / Hazards regarding extinguishing of lithium-ionbattery fires onboard shipsLif, William, Sehlin, André January 2020 (has links)
Detta arbete söker att svara på vilka risker som måste beaktas vid bekämpningen av en brand i litium-jonbatterier ombord på fartyg. Antalet elbilar med denna typ av batterier ökar i popularitet och transporteras ofta via fartyg. För att få svar på vilka risker som då uppstår och hur de ska beaktas, har en serie semistrukturerade intervjuer genomförts med räddningstjänsten i olika län, samt forskare som har kunskap inom ämnet. Arbetet har visat på att det finns flera olika risker som kan uppkomma med ett litium-jonbatteri, brand och termisk rusning är några av riskerna som kan uppkomma. Vid dessa händelser släpps ett flertal farliga gaser ut där den mest kända är vätefluorid. Andra risker som uppkommer varierar mellan den höga värmen av 1150°C från branden, till det faktum att en sådan brand inte kan kvävas då den förser sig själv med syre vilket gör att den kan fortsätta brinna. Det finns inga tydliga regelverk eller riktlinjer för hur dessa bränder ska bekämpas på bästa sätt och detta kräver ytterligare forskning för att tydliggöra hur brand i litium-jonbatterier skall hanteras. / This study is searching for the answer of what hazards must be considered when fighting fires in lithium-ion batteries on board ships. The number of electric vehicles with this type of battery are increasing in popularity and are often transported through the shipping industry. To highlight the hazards and how to handle them, a couple of semi-structured interviews were conducted with firefighters and researchers with knowledge in the subject. The study has looked at the risks that arise when a lithium-ion battery has a thermal runaway, during which several dangerous gases are emitted where the most known is hydrogen fluoride. Other hazards that arise vary from high heat at points as high as 1150° C, to the fact that such fire cannot be suffocated as it is selfsufficient in oxygen. There are no clear regulations or guidelines on how to fight this kind of fire and further research is required to clarify how to handle these types of fires.
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