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1
Silva, Amanda Falcão da 1986. "Biodisponibilidade de fluoreto a partir de dentifrício contendo carbonato de cálcio ou sílica como abrasivo." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/289529.
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Orientador: Livia Maria Andaló Tenuta.Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba.
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Resumo: Dentifrícios fluoretados tem sido considerados responsáveis pelo declínio de cárie ocorrido mundialmente, entretanto, são também considerados fatores de risco para fluorose dental. Todavia, não tem sido encontrada correlação entre a dose de ingestão de fluoreto (F) pelo dentifrício, na idade de risco para o desenvolvimento de fluorose e sua posterior prevalência. Uma das razões para esse achado é que a concentração total de F no dentifrício e não aquela biodisponível (fração solúvel que é absorvida) tem sido considerada no cálculo da dose de ingestão. Nesse contexto, dentifrícios fluoretados contendo carbonato de cálcio como abrasivo apresentam parte do F total indisponível para ser absorvido, ou seja, na forma insolúvel, que sofre aumento em função do tempo...Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital
Abstract: Fluoride toothpastes are considered responsible for caries decline worldwide but they are also considered as risk factors for dental fluorosis. Nonetheless, there has been no correlation between fluoride (F) intake from toothpaste in the age of risk for developing fluorosis and its subsequent prevalence. One reason for this finding is that the total F concentration in toothpastes and not that bioavailable (soluble fraction which is absorbed) has been considered in calculation of the F dose ingested...Note: The complete abstract is available with the full electronic document
Mestrado
Cariologia
Mestre em Odontologia
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Bostwick, Aaron A. "Impact on calcium fluoride reactivity and electronic structure of photon and electron stimulated fluorine desorption /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/9721.
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Partey, Frederick Kenneh. "SOURCE OF FLUORINE AND PETROGENESIS OF THE RIO GRANDE RIFT TYPE BARITE-FLUORITE-GALENA DEPOSITS." Miami University / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=miami1092262697.
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Mateus, Tavares Ana Raquel. "Etude de la précipitation de la fluorine en milieu alcalin et application à un procédé en réacteur à lit fluidisé." Thesis, Saint-Etienne, EMSE, 2013. http://www.theses.fr/2013EMSE0710/document.
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Le procédé adopté par COMURHEX pour le traitement des effluents très chargés en fluor est basé sur l’addition d’un composé alcalin Ca(OH)2 (portlandite) pour faire précipiter de la fluorine (CaF2). Mis en œuvre par le passé dans un décanteur le développement d’un nouveau procédé en lit fluidisé a été envisagé pour augmenter l’efficacité du traitement des effluents. Des essais concluants ont été réalisés sur une installation pilote qui ont démontré l’efficacité de la précipitation en lit fluidisé à assurer une réduction satisfaisante de la concentration du fluor. Cependant, les phénomènes mis en jeu dans le réacteur sont mal connus.Notre objectif principal est la maîtrise de la précipitation de la fluorine dans le réacteur à lit fluidisé ainsi qu’une meilleure compréhension des mécanismes mis en jeu. Pour ce faire, il a été nécessaire de reprendre l’étude thermodynamique du système KOH-portlandite-calcite-fluorine, de manière à étendre les données existantes aux fortes concentrations de KOH en solution. Un modèle thermodynamique capable de prédire la solubilité des solides en présence de variations de la concentration de la potasse et de la température du système a été établi.La deuxième partie du travail a été focalisée sur la compréhension des mécanismes mis en jeu pendant la formation de la fluorine. Les expériences réalisées au laboratoire ont conduit à l’obtention d’une fluorine issue d’une conversion de la portlandite. Ce mécanisme a été modélisé en considérant que le remplacement de la portlandite par la fluorine s’explique par un modèle à cœur rétrécissant contrôlé par la limitation diffusionnelle du fluorure dans la couche de fluorine formée. La dernière partie expérimentale de ce travail a été réalisée sur le pilote à lit fluidisé. Les expériences effectuées n’ont pas donné de résultats satisfaisants. Il n’a pas été possible de faire faire fonctionner le pilote de façon cohérente avec les objectifs de son dimensionnement. En particulier, compte-tenu de la très petite taille des particules, les débits de fonctionnement conduisent à l’envolement de celles-ci, mais pas à l’établissement de l’état fluidiséThe method used by COMURHEX for the treatment of fluorine-rich effluents relies on the addition of solid Ca(OH)2 (portlandite) to precipitate fluorite (CaF2) in strongly alkaline solutions. This method is effective in a settler, and the development of a new fluidized bed process has been proposed to increase its efficiency. Successful assays were conducted on a pilot scale and they demonstrated that precipitation in a fluidized bed reactor actually ensures a satisfactory defluorination. However, the phenomena involved remained poorly known, and the main goal of the present work was to elucidate the mechanisms, their kinetics, and to control the crystallization.Our first contribution is a thermodynamic reappraisal of the KOH–portlandite–calcite system that extends existing solubility data to higher KOH concentrations in solution and incorporates new solubility data for fluorite. The outcome is an aqueous speciation model (Pitzer type) accounting for the solids solubility as a function of the KOH concentration and the temperature, and allowing portlandite undersaturation and fluorine supersaturation to be evaluated in process solutions.Our second contribution focuses on the kinetics and the mechanisms involved during the formation of fluorite, using various mixing designs in batch reactors. Reaction rates are fast, except in experiments involving dilute reactants. Microprobe and granulometric data both indicate that much of the fluorine results from the conversion of the portlandite grains. A shrinking core model controlled by diffusive transfer of fluoride in the porous fluorite corona successfully fits the kinetics of fluorine uptake and the particle grain size.The last part of the experimental work was carried out on a small fluidized bed pilot. These experiments were poorly conclusive. The very small particle size and the large flow rates lead to particle blow off, but not to fluidization. As a consequence, the capacity of the fluidized bed to promote an increase of the particle grain size remains largely unknown
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Dolejš, David. "Thermodynamics and phase equilibria of the silicate-fluoride-H₂O systems : implications for fluorine-bearing granites." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=85066.
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The progressive enrichment in volatiles and light incompatible elements observed during upper-crustal differentiation of granitic and rhyolitic magmas leads to significant changes in melt physical-chemical properties and has important implications for ore deposition and volcanic devolatization. Thermodynamic calculations and experimental studies of melting equilibria in the Na 2O-K2O-Al2O3-SiO2-F 2O-1-H2O system are used to evaluate mineral stabilities, fluid compositions, the extent of fluoride-silicate liquid-liquid immiscibility, fluorine and water solubility limits and differentiation paths of natural fluorine-bearing silicic magmas. The interaction of fluorine with rock-forming aluminosilicates corresponds to progressive fluorination by the thermodynamic component F2O-1. Formation of fluorine-bearing minerals first occurs in peralkaline and silica-undersaturated systems that buffer fluorine concentrations at very low levels (villiaumite, fluorite). The highest concentrations of fluorine are achieved in peraluminous silica-oversaturated systems, saturated with fluorite or topaz. Thermodynamic models of fluorosilicate melts indicate clustering of silicate tetrahedra in the Na2O-SiO 2-F2O-1 system, whereas initial NaAl-F short-range order evolves into partial O-F disorder in the albite-cryolite system. Experiments performed at 520-1100°C and 0.1-100 MPa completely describe liquidus relations and differentiation paths of fluorine-bearing felsic magmas. Coordination differences and short-range order effects between [NaAl]-F, Na-F vs. Si-O lead to the fluoride-silicate liquid immiscibility, which extends from the silica-cryolite binary through the peralkaline albite-silica-cryolite ternary and closes in multicomponent, topaz-bearing systems owing to the destabilizing effect of increasing peraluminosity. Liquidus relations indicate that fluoride-silicate liquid-liquid immiscibility is inaccessible to quartz-feldspar-saturated granitic melt
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Mamuse, Antony. "Fluoride contaminated drinking water in Gokwe District (NW Zimbabwe) : spatial distribution, lithostratigraphic controls and implications for human health /." Curtin University of Technology, Department of Applied Geology, 2003. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=15235.
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The supply of drinking water in Gokwe District (NW Zimbabwe) is almost entirely based on groundwater drawn from boreholes and open dug wells. In certain areas of the district, the occurrence of dental fluorosis has been linked to excessive fluoride in the water supplies. A high prevalence of dental fluorosis (about 62%) was previously recorded among school children in the district. The aim of this study was to determine relationships between the spatial distribution of fluoride content in drinking water supplies in Gokwe, and lateral and vertical geological variation. A total of 224 water samples were collected from 196 water sources in the study area (a further 18 water sources just outside the study area were also sampled). All the samples were analysed for fluoride in the field using the fluoride ion selective electrode method (FISE). One hundred and fifty nine duplicate samples were analysed for fluoride and common anions and cations using High Performance Ion Chromatography (HPIC) in the laboratory. Two main groups of computer programmes were employed: (1) Geographic Information System (ArcView® GIS) was used to store, analyse and display multiple layers of surface geologic and geographic information, and (2) a three-dimensional visualisation programme (Rockworks) was used to interpret and illustrate site stratigraphy based on borehole information. Results indicated that the fluoride content of drinking water in the study area ranges from 0 to 9.65 mg/L. Forty-seven water sources (24%) yielded water containing fluoride in excess of the World Health Organisation's (WHO) health limit of 1.5 mg/L F. Of the 47 high fluoride water sources, 43 were boreholes (pumped or artesian). The shallower water sources (dug wells, streams and dams) largely yielded low-fluoride water.The groundwater fluoride contamination is stratigraphically controlled and originates from carbonaceous material (carbonaceous shales, carbonaceous mudstones and coaly material) within the Lower Madumabisa and Middle Wankie Members of the Lower Karoo Group. It has been shown that in general the greater the proportion of carbonaceous material intersected by a borehole, the greater the fluoride concentration of the water. Probable mineral sources of fluoride within the carbonaceous material include fluorapatite, kaolinite and trona. Chemical parameters that appear to influence the concentration of dissolved F in the water supplies include total dissolved solids (TDS), NaCl and pH. In relatively low fluoride waters, F concentrations generally increase with TDS and NaCl concentrations, whereas the highest F concentrations are found in moderately alkaline (pH 7.8-9) waters. Based on ranges of fluoride concentration in drinking water, fluorosis-risk zones were identified and have been illustrated on a fluorosis-risk map. The zones are: No Risk Zone (0-1.5 mg/L F), Moderate Risk Zone (1.5-3.0 mg/L F), High Risk Zone (3.0-6.0 mg/L F) and the Very High Risk Zone (6.0-10.0 mg/L F). The map suggests that groundwater available to people occupying 3650 km z (60.8%) of the study area potentially contains excessive fluoride (F>1.5 mg/L), presaging the occurrence of dental fluorosis, skeletal fluorosis and crippling skeletal fluorosis in the area. Different strategies may be employed to ameliorate the fluoride problem in Gokwe.
These include sinking new boreholes to optimal depths and in appropriate locations, promoting the use of surface water and shallow groundwater, resettlement and defluoridation. However in order to fully understand the problem and to prescribe these or other solutions more comprehensively, multi-disciplinary studies may be required. Such studies may consider isotopic dating of water to investigate any relationships between fluoride concentration and residence time of water, geochemical analyses of rocks and soils, detailed fluorosis epidemiology studies and test-scale defluoridation investigations.
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Catani, Danilo Bonadia. "Influencia do heterocontrole de fluor na ocorrencia de fluorose na dentição permanente." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/289316.
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Orientadores: Jaime Aparecido Cury, Maria da Luz Rosario de SousaDissertação (mestrado profissional) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: O objetivo geral deste estudo, composto por dois trabalhos, foi analisar as possíveis relações entre a exposição a níveis diferenciados de íon flúor na água de abastecimento público e a presença de fluorose dentária na dentição permanente, e analisar os possíveis fatores associados. No primeiro trabalho foi analisada a concentração de fluoreto em amostras de água enviadas de 07 cidades do estado de São Paulo, além de um município no Estado de Minas Gerais e outro no Ceará. As coletas das amostras de água foram realizadas no período de 1996 a 2002, sendo as mesmas avaliadas utilizando-se um analisador de íons (Orion 96-09 e analisador de íons EA-940 previamente calibrados com padrões contidos de 0,125 a 1,0 mg F/ml , com 1,0 ml de Tisab II, ou seja, Tisab II a 50%) acoplado a um eletrodo de flúor previamente calibrado. Num total de 2667 amostras no período analisado, observou-se que mais que 59,2% das amostras encontraram-se dentro dos padrões considerados ótimos (0,6?0,8 ppm F), sendo 6,3% das amostras com valores menores que 0,4 ppm F, 18,1% entre 0,4 a 0,6 ppm F,13,3% entre 0,8 a 1,0 ppm F e 3,1% com valores maiores que 1 ppm F. Pode-se concluir, portanto, que a maioria das amostras coletadas estavam no considerado nível ótimo (0,6?0,8 ppm F), contudo verifica-se que há dados e regiões que estão fora do padrão considerado ideal, sendo importante a manutenção do heterocontrole. O objetivo do segundo trabalho foi verificar a prevalência da fluorose dentária em escolares de 7 anos de idade residentes em dois municípios que se diferenciam quanto aos níveis ótimos de flúor na água de abastecimento público, e investigar possíveis fatores associados. A amostra deste estudo foi composta por 386 crianças de 7 anos de idade, nascidas no ano de 1997, matriculadas em escolas públicas e instituições privadas de ensino em municípios que realizaram heterocontrole de flúor na água de 1998 a 2002. A fluorose dental foi avaliada por meio do índice de Dean. Foram examinados os incisivos superiores permanentes, previamente secos e sob iluminação artificial com equipamento odontológico portátil. Considerou-se como presença de fluorose as formas: questionável, muito leve, leve, moderada e severa. Variáveis sócio-demográficas e questões sobre saúde bucal foram avaliadas com um questionário estruturado enviado aos pais/responsáveis. Os resultados mostraram que a prevalência de fluorose no município com níveis oscilantes de íon flúor foi de 31,40% e no município com níveis homogêneos de fluoretos 79,91%. Entretanto, em ambos os municípios, prevaleceu o grau "muito leve" de fluorose, portanto sem comprometimento estético. A prevalência de fluorose foi associada com o município com teores de flúor constante na água e com um único indicador sócio-econômico
Abstract: The general objective of this paper, based over two works, was to analyze possible relationships among different levels of fluoride ions in the public water supply and the presence of dental fluorosis in permanent teeth. Associated factors are also to be analyzed. At the first stage of the process, fluoride concentration present in water samples sent from 7 cities of São Paulo State, one city of Minas Gerais State and another from Ceará State were to be analyzed. All the water sample collections took place during the period of 1996 and 2002 and an ion analyzer was used in the process of evaluation (Orion 96-09 and a ion analyzer EA-940 previously gauged with patterns of 0.125 to 1.0 mg F/ml, with 1.0 ml of Tisab II, so, Tisab II at 50%) coupling to a fluoride electrode previously gauged as well. Over a total of 2667 samples collected in the mentioned period it was noted that more than 59.2% of them were found to contain patterns considered great (0.6-0.8 ppm F ), 6.3% of them with lower values than 0.4 ppm F; 18.1% of them between 0.4 to 0.6 ppm F; 13.3 % between 0.8 and 1.0 ppm and 3.1% with values larger than 1 ppm F. In view of the aforementioned results it is possible to concluded that the majority of collected samples were in the level range considered optimal (0.6-0.8 ppm F). However, it was possible to also verify that some of the results and regions are out of the considered ideal pattern implying that hetero-controlling maintenance is important. The objective of the second work was to evaluate the prevalence and correlates of dental fluorosis in school children aged 7 years living in two cities of São Paulo State, Brazil, with fluoridation of water supplies, with emphasis in the effects of external control of the fluoride levels. The study population comprised 386 children, all born in 1997 and enrolled in public and private schools from 2 municipalities had fluoride external control of the fluoride levels from 1998 to 2002. The upper permanent maxillary incisors were examined under artificial light and the aid of an air syringe. The Deanâ?¿s Index was utilized to identify dental fluorosis. In this study dental fluorosis were considered such as: questionable; very mild; mild; moderate and severe. Socio-demographics and dental history were assessed with a structured questionnaire answered by childrenâ?¿s parents. Correlates of fluorosis were assessed using multivariate logistic regression (p<0.05).The result showed that the prevalence of fluorosis in the municipality that had more variation in the levels of fluoride was 31.40% and in the municipality that had less variation in the levels of fluoride 79.91%. However, in both municipalities the â?¿very mildâ?? level of fluorosis was the most common finding. Fluorosis were associated to the city with homogeneous levels of fluoride
Mestrado
Mestre em Odontologia em Saúde Coletiva
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Crispim, Cristina Penna. "Aspectos da qualidade da água potável de Ribeirão Preto - SP." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/59/59138/tde-15072013-152308/.
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A cidade de Ribeirão Preto é abastecida com água proveniente do Aquífero Guarani, sendo apenas fluoretada e clorada antes da distribuição. O objetivo desse trabalho foi avaliar a qualidade da água que a população está consumindo com relação às concentrações de fluoreto, chumbo e ferro. Além disso, foi investigada se a concentração de ferro poderia ser utilizada como marcadora da contaminação por chumbo na água potável. Foram investigadas 145 residências de 4 bairros antigos de Ribeirão Preto (casas com mais de 40 anos), havendo pelo menos uma criança moradora por residência. Um bairro novo (menos de 10 anos) foi escolhido para controle. Amostras de água foram coletadas na torneira da cozinha e do quintal, sendo a 1ª alíquota coletada após pelo menos 6 h de estagnação e a 2ª alíquota após 5 minutos de escoamento. A concentração dos íons fluoreto foi determinada por eletrodo combinado íon-seletivo e cromatografia iônica; chumbo por ET AAS e ICP-MS; e ferro por espectrofotometria. As concentrações de fluoreto nas amostras (n = 281) variaram de 0,052 a 1,01 mg L-1. Considerando apenas 1 algarismo significativo e as amostras provenientes da cozinha, observou-se que 30% das casas estiveram fora do padrão de potabilidade estabelecido pela Resolução SS-65 (2005), isto é, de 0,6 a 0,8 mg L-1. Considerado 2 algarismos, essa percentagem passou para 45%. Um baixo consumo de fluoreto pelas crianças pode não prevenir eficientemente a formação de cáries, enquanto que concentrações elevadas podem levar à fluorose dentária. As concentrações de chumbo variaram de 0,025 a 58,4 µg L-1 (n = 562), sendo que a concentração máxima permitida pela Portaria 2.914 (Ministério da Saúde) é de 10,0 µg L-1. Para todas as casas avaliadas, as concentrações de chumbo na água da torneira da cozinha não ultrapassaram 5,00 µg L-1, caracterizando um baixo risco de contaminação por chumbo por essa via. Para 2 alíquotas de água coletadas na torneira do quintal, a concentração de chumbo ultrapassou o limite tolerável para chumbo, porém, o uso dessa água para ingestão é pouco usual. Possivelmente a contaminação observada seja oriunda da própria torneira e outras partes metálicas, pois após escoamento da água por 5 minutos, a concentração de chumbo caiu dentro dos valores permitidos. As concentrações de ferro variaram de 13,40 a 4.119 µg L-1 (n = 189; 1ª alíquota), sendo a concentração máxima permitida de 300 µg L-1 (Portaria 2.914). Em 4 casas a água do quintal apresentou concentração superior a permitida, mas na água da cozinha a concentração foi de 8 a 66 vezes menor. Isso indica que a torneira do quintal pode ser uma grande fonte de contaminação de ferro. Apesar do coeficiente de correlação linear entre a concentração de ferro e chumbo na água ser estatisticamente significativo (r = 0,410; n = 184), essa correlação foi relativamente baixa para sugerir o uso do ferro como marcador da contaminação por chumbo.The city of Ribeirão Preto is supplied with water from the Guarani Aquifer, that is only fluoridated and chlorinated before distribution. The objective of this study was to evaluate the quality of drinking water that the population is consuming with respect to the concentrations of fluoride, lead and iron. Furthermore, it was investigated if the concentration of iron could be used as a marker to infer lead contamination in drinking water. We investigated 145 residences with more than 40 years of age in 4 districts of Ribeirão Preto, with at least one resident child. One new district (less than 10 years) was selected as a control group. Water samples were collected from the kitchen and the yard taps. The 1st aliquot was collected after at least 6 h of stagnation and the 2nd after leaving the water running for 5 minutes. The concentration of fluoride ions was determined by combined ion-selective electrode and ion chromatography; lead by ET AAS and ICP-MS; and iron by spectrophotometry. The fluoride concentrations in the samples varied from 0.052 to 1.01 mg L-1 (n = 281). Considering only 1 significant digit and the kitchen samples, it was observed that 30% of the homes did not attend the legislation for fluoride in drinking water (Resolution SS-65, 2005), that is, from 0.6 to 0.8 mg L-1. Considering 2 significant digits, this percentage increased to 45%. A low intake of fluoride by children cannot effectively prevent the formation of dental caries, while high concentrations can cause dental fluorosis. Lead concentrations ranged from 0.025 to 58.4 µg L-1 (n = 562), and the maximum permited by the law 2,914 (Ministry of Health) is 10.0 µg L-1. For all homes investigated, lead concentrations from the kitchens tap water did not exceed 5.00 µg L-1, showing there is a low risk of lead contamination through this pathway. For 2 aliquots of water collected from the yards tap, the concentration of lead exceeded the tolerable limit, however, the use of this water for ingestion is unusual. Possibly this contamination might come from the tap itself and from others metal parts, because after running the water for 5 minutes the lead concentration fell below the permitted value. Iron concentrations varied from 13.40 to 4,119 µg L-1 (n = 189, 1st aliquot), and the tolerable limit is 300 µg L-1 (law 2.914). In 4 houses the water from the year tap had concentrations above the limit, while in the kitchen water iron concentrations were from 8 to 66 times lower. This indicates that the tap material from the yard can be a large source of iron contamination. Although the linear correlation coefficient between iron and lead concentrations in the drinking water was statistically significant (r = 0.410; n = 184), this correlation was relatively low to suggest the use of iron as a marker of contamination by lead.
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Forni, Tania Izabel Bighetti. "Fatores associados à fluorose dentária em área com água fluoretada." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/6/6135/tde-22092011-145657/.
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O objetivo do estudo foi identificar fatores associados à fluorose dentária em Ribeirão Pires-SP, com água fluoretada desde 1985 e heterocontrole dos teores de flúor desde 1996. Foi realizada pesquisa epidemiológica tipo caso-controle com projeto aprovado pelo Comitê de Ética da FSP-USP. A população de estudo foi adolescentes de 12 a 15 anos de idade, identificados em 23 escolas de ensino fundamental por cirurgiã-dentista capacitada (k=0,79). Foram considerados casos 667 adolescentes com graus de fluorose 2, 3, 4 e 5 (Índice de Dean). A partir da região de residência dos casos, foram identificados 416 controles, de mesmo sexo e idade, com grau de fluorose 0, procurando-se garantir a mesma distribuição por região. Casos e controles (5 por cento ) foram examinados pela pesquisadora (k=0,90). Um formulário de entrevista foi construído, utilizando-se técnica de pesquisa exploratória, contendo dados relativos a variáveis demográficas, geográficas, escolaridade dos pais/responsáveis e relacionados à exposição a fontes de flúor em três ciclos (1o ano de vida, 1 a 3 anos e 4 a 6 anos de idade). A coleta dos dados foi feita por 55 entrevistadores cujo treinamento contemplou repetição de entrevistas e discussão de aspectos relevantes. Foram realizadas 509 entrevistas (319 casos e 190 controles). As respostas foram transcritas para digitação de forma dupla, com validação do banco de dados. A distribuição percentual do evento nos casos e controles nas categorias de exposição foi analisada utilizando-se o teste de Qui-quadrado de Pearson. Na análise univariada identificou-se as de maior associação para elaboração de modelos de regressão logística múltipla não condicional. A análise mostrou risco significativo para fluorose dentária nas seguintes situações de exposição: quando os adolescentes usaram dentifrício fluoretado nos 6 primeiros anos de vida (OR= 2,25; p=0,048) e eram responsáveis pela sua colocação no período de 4 a 6 anos de idade (OR=2,17; p=0,000), quando foi utilizada água fluoretada para preparo de alimentos nos 6 primeiros anos de vida (OR=2,90; p=0,026) e a interação entre maior escolaridade do pai e menor escolaridade da mãe (OR=2,15; p=0,024). Recomenda-se que os serviços de saúde considerem os resultados no planejamento das ações de educação em saúde reforçando o uso adequado de dentifrícios, além de manter a política de vigilância sanitária dirigida a múltiplas fontes de flúorThe purpose of this study was to identify factors associated with fluorosis in the city of Ribeirão Pires SP, which has fluoridated water since 1985, (with hetero-controls of fluoride levels since 1996). It was done an epidemiological case-control study which project was approved by the Ethics Committee of the FSP-USP. The study population consisted of 12 to 15 year old teenagers, identified by a trained dentist (k=0.79) in 23 high schools. 667 teenagers who showed fluorosis levels of 2, 3, 4 or 5 (Dean Index) were selected for this study. 416 children of the same age and sex and living in the same area were also identified as controls (fluorosis level = 0) in order to assure the same distribution by region. Cases and controls (5 per cent ) were examined (k=0.90) by the author. A questionnaire was elaborated, using the exploratory survey method, with data related to demographic, geographic, education level of parents/guardians, related to fluoride sources exposure in 3 different periods of life (first year, 1 to 3 years and 4 to 6 years of age). Data was collected by 55 interviewers whose training consisted of repeated interviews and case discussions. 509 interviews were made (319 cases and 190 controls) and the responses were transcribed and typed twice, with posterior validation of the database. Percentile distribution of the events of cases and controls of exposition categories were analyzed using Pearson Chi-Square test. In the univariable analysis, the variables with higher match were identified for posterior construction of models of non-conditional multiple logistic regression analyses. The analysis of regression showed significant risk for dental fluorosis in the following exposure situations: when the teenagers used fluoridated dentifrice during the first 6 years of life (OR=2.25; p=0.048) and they were responsible for its placement in a period of 4 to 6 years (OR=2.17; p=0.000), when it was used fluoridated water for food preparation during the 6 first years of life (OR=2.90; p=0.026) and in the relation of high educational level of the father and lower educational level of the mother (OR=2.15; p=0.024). It is recommended that the health services should consider these results in the planning of actions of health education activities in order to emphasize the importance of adequate use of dentifrices, and to maintain their sanitary control policies focused on multiple sources of fluoride
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Barbosa, Tatiana de Freitas [UNESP]. "Fluorose dentária e concentração de flúor nas unhas de crianças residentes em diferentes áreas fluoretadas." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/95402.
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barbosa_tf_me_araca.pdf: 715889 bytes, checksum: f9c4cf0b3fff1513c875f5ce77fdf964 (MD5)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
A fluoretação das águas de abastecimento público tem ocasionado significante redução na prevalência da cárie em diferentes populações, entretanto, a exposição ao flúor pelo uso de diferentes métodos tem trazido preocupações quanto ao aumento na prevalência de fluorose dentária. Por isso, estudos sobre os fatores de risco associados à fluorose são necessários, além do acompanhamento contínuo e efetivo da exposição ao flúor, por diferentes meios, incluindo mais recentemente os marcadores biológicos para esse íon, como a unha, que também reflete o nível de exposição crônica, desde que um indivíduo tenha uma ingestão de flúor relativamente constante. Assim, objetivou-se analisar o teor de fluoreto das águas de abastecimento público em diferentes áreas de um município, uma abastecida por poços profundos e outra pela estação de tratamento de água (ETA), e verificar se os teores de fluoretos encontrados refletem diferenças nas concentrações de flúor observadas nas unhas das crianças de 12 anos e na prevalência de fluorose dentária. Para isso, foram selecionados 43 pontos para coleta de amostras de água, abrangendo as 17 fontes de abastecimento existente no município. A população de estudo foi constituída por 60 crianças, de 12 anos de idade, nascidas e moradoras permanentes nas duas áreas de estudo, seguindo os critérios de inclusão, sendo uma com excesso e outra sem excesso de flúor nas águas de abastecimento público. As amostras de água, coletadas mensalmente nos pontos previamente estabelecidos, foram analisadas em duplicata no período de janeiro a dezembro de 2009, utilizando-se um analisador de íons acoplado a um eletrodo específico para flúor. Coletas e análise do flúor nas unhas das crianças foram realizadas, utilizando-se a técnica da microdifusão facilitada por HMDS. Para verificação da fluorose...
The fluoridation of public water supply has caused a significant reduction in the prevalence of caries in different populations, however, exposure to fluoride by using different methods has brought concerns about the increasing prevalence of dental fluorosis. Therefore, studies on the risk factors associated with fluorosis are needed, besides the efficient and continuous monitoring of fluoride exposure by various means, including most recently the biological markers for this ion, such as fingernail, that also reflects the level of chronic exposure, as long as an individual has a relatively constant intake of fluoride. The objective was to analyze the fluoride content of public water supply in different areas of a district, one served by deep wells and one by the water treatment station (WTS), and check if the levels of fluoride found reflect differences in the concentrations of fluoride observed in nails of 12 years old children and the prevalence of dental fluorosis. For this, 43 points were selected to collect water samples, covering the 17 existing sources of supply in the municipality. The study population consisted of 60 children, 12 years old, born and permanent residents in both areas of study, following the inclusion criteria, one with and one without too much fluoride excess in public water supply. Water samples collected monthly in points previously established, were analyzed in duplicate in the period from January to December of 2009, using an ion analyzer coupled to a specific electrode for fluoride. Sampling and analysis of fluoride in children nails were done, using the technique of facilitated microdiffusion HMDS. For verification of dental fluorosis we used the modified DEAN index .Of the total samples studied (n=512), 44% (n=224) had adequate levels and 56% (n =288) inadequate levels, and 10% (n=49) lower levels and 46% (n=239) higher... (Complete abstract click electronic access below)
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Camara, Danielle Mendes da. "Avaliação in vitro da eficácia de dentifrícios de baixa concentração de fluoreto suplementados com hexametafosfato sobre o processo de desmineralização do esmalte /." Araçatuba : [s.n.], 2011. http://hdl.handle.net/11449/95446.
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Orientador: Kikue Takebayashi SassakiBanca: Alberto Carlos Botazzo Delbem
Banca: Marília Afonso Rabelo Buzalaf
Resumo: Formulações de dentifrícios com concentrações reduzidas de fluoreto (F) têm sido estudadas para diminuir o risco de fluorose dentária. O objetivo do trabalho foi avaliar a eficácia de dentifrícios com concentrações reduzidas de F (250 μgF/g), suplementados com hexametafosfato (HMP) sobre a desmineralização do esmalte de dente bovino. Blocos de esmalte foram submetidos a repetidas ciclagens de pH alternadas com tratamentos (2x/dia) com dentifrícios sem F contendo HMP nas concentrações de 0, 0,25, 0,5, 1,0, 2,0 e 3,0%, dentifrícios com 250 gF/g suplementados com HMP nas mesmas concentrações, placebo (sem F e HMP), um com 500 μgF/g, outro com 1100 μgF/g e um comercial (Crest, de 1100 gF/g). Após as ciclagens determinou-se a dureza de superfície final (SHf), perda integrada de dureza de subsuperfície (ΔKHN) e o conteúdo de F no esmalte. Os resultados foram submetidos à ANOVA e teste de Bonferroni (p<0.05). O grupo 250 gF/g com 0,5% de HMP apresentou maior valor de SHf, e menor ΔKHN, seguido do grupo de 250 gF/g com 1,0% de HMP que ficou semelhante ao 1100 gF/g e Crest. HMP não interferiu na incorporação de F pelo esmalte em concentrações menores que 3%. Além disso, a adição de 0,5% de HMP a um dentifrício sem F causou um aumento de SHf e uma redução de ΔKHN em comparação ao placebo. Conclui-se que é possível reduzir a concentração de F a 250 gF/g e se obter uma ação comparável de um dentifrício comercial sobre a desmineralização do esmalte bovino através da suplementação com hexametafosfato nas concentrações de 0,5 e 1%
Abstract: Formulations of dentifrices with reduced concentrations of fluoride (F) have been studied to decrease the risk of dental fluorosis. The aim of this study was to evaluate the efficacy of dentifrices with low concentration of F (250 μgF/g), supplemented with hexametaphosphate (HMP) on the demineralization of bovine tooth enamel. Blocks of enamel were submitted to repeated pH cyclings alternated with treatments (2x/day) with dentifrices without F or containing 250 gF/g supplemented with HMP at concentrations of 0, 0,25, 0,5 1,0, 2,0 e 3,0%, dentifrices supplemented with HMP the same concentrations, placebo (without F and HMP), a dentifrice with 500 μgF/g, another with 1100 μgF/g and a commercial dentifrice (Crest, 1100 gF/g). After cycling, the following analysis were conducted: final surface hardness (SHf), subsurface hardness integrated loss (ΔKHN) and the content of F on enamel. The results were submitted to variance analysis and Bonferroni test (p<0.05). The group of 250 gF/g with 0,5% HMP showed the highest SHf value and the lowest ΔKHN value, followed by the group supplemented with 1,0% HMP which was similar to 1100 gF/g and Crest groups. HMP did not impair the uptake of F by enamel at concentrations lower than3%. Furthermore the addition of 0,5% HMP to a non fluoridated dentifrice caused a rise on SHf and a decrease on ΔKHN in comparison to placebo. It was concluded that it is possible to reduce the concentration of F to 250 μgF/g and obtain an action similar to a commercial dentifrice on the demineralization of enamel by supplementation with hexametaphosphate in concentrations of 0.5 and 1%
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Evangelakis, Georgios A. "Superconducteurs ioniques de structure fluorine : A) mesure de la conductivité ionique du fluorure de strontium : B) étude des propriétés thermodynamiques du fluorure de calcium par simulation numérique." Nancy 1, 1989. http://www.theses.fr/1989NAN10311.
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Dans ce travail nous présentons les résultats d'une étude expérimentale de la conductivité ionique du fluorure de strontium, ainsi que ceux d'une investigation des propriétés thermodynamiques du fluorure de calcium dans le domaine de conduction superionique par simulation à l'aide de la dynamique moléculaire. Les mesures de la conductivité ionique du fluorure de strontium ont été effectuées à haute température (700-1350 K) en fonction de la fréquence du champ électrique utilisé (10 HZ-10 MHZ). Pour toutes les températures exploitées, nous avons trouvé une dépendance de la conductivité en fonction de la fréquence. L'analyse des résultats au moyen de diagrammes d'impédance complexe a montré que cette dépendance est due aux mauvais contacts entre l'échantillon et les électrodes. L'utilisation de ces diagrammes a permis de déterminer la conductivité intrinsèque du matériau. Des diagrammes d'arrhenius pour la conductivité nous avons pu déterminer les énergies d'activation apparentes pour les différentes régions de conduction. Celles-ci ne permettent malheureusement pas d'identifier les mécanismes atomiques de superconductivité ionique. La simulation par la dynamique moléculaire (DM) du fluorure de calcium a été effectuée en utilisant un potentiel d'ions rigides. Nous avons calculé la constante de diffusion, le facteur de structure, la chaleur spécifique, le déplacement quadratique moyen et leur variation en fonction de la température. Les résultats sont en bon accord avec l'expérience, ce qui justifie à postériori le choix du potentiel. En utilisant la DM hors d'équilibre dans la région de réponse linéaire, la superconductivité ionique du fluorure de calcium a pu être obtenue. Les calculs indépendants de la conductivité et la constante de diffusion, fournissent le rapport de Haven, HR 0. 34, dans la région supérionique. Cette valeur suggère que la superconductivité ionique de ce matériau est due à un mécanisme collectif et corrélé ce qui est confirmé par l'analyse des trajectoires des particules
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Bhowmick, Somnath. "Theory on lower bound energy and quantum chemical study of the interaction between lithium clusters and fluorine/fluoride." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4394.
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En chimie quantique, le principe variationnel est largement utilisé pour calculer la limite supérieure de l'énergie exacte d'un système atomique ou moléculaire. Des méthodes pour calculer la valeur limite inférieure de l'énergie existent mais sont bien moins connues. Une méthode précise pour calculer une telle limite inférieure permettrait de fournir une barre d'erreur théorique pour toute méthode de chimie quantique. Nous avons appliqué des méthodes de type variance pour calculer différentes énergies limites inférieures de l'atome d'hydrogène en utilisant des fonctions de base gaussiennes. L'énergie limite supérieure se trouve être toujours plus précise que ces différentes limites inférieures, i.e. plus proche de l'énergie exacte. L'importance de points singuliers sur l'évaluation de valeurs moyennes d'opérateurs quantiques a également été soulignée.Nous avons étudié les réactions d'adsorption d'un atome de fluor et d'un ion fluorure sur de petits agrégats de lithium Li$_n$ (n=2-15), à l'aide de méthodes de chimie quantique précises. Pour le plus petit système, nous avons montré que la formation de complexes stables Li$_2$F et Li$_2$F$^-$ se produit par un transfert d'électrons sans barrière et à longue portée, de Li$_2$ vers F pour le système neutre et l'inverse pour le système anionique. De telles réactions pourraient être rapides à très basse température. De plus, les complexes formés présentent des caractéristiques uniques de "longue liaison". Pour les systèmes plus gros Li$_n$F/Li$_n$F$^-$ ($n\geqslant4$), nous avons montré que les énergies d'adsorption peuvent être aussi grandes que 6~eV selon le site d'adsorption et que plus d'un état électronique est impliqué dans le processus d'adsorption. Les complexes formés présentent des propriétés intéressantes de "super alcalins" et pourraient servir d'unités de base dans la synthèse de composés à transfert de charge avec des propriétés ajustablesIn quantum chemistry, the variational principle is widely used to calculate an upper bound to the true energy of an atomic or molecular system. Methods for calculating the lower bound value to the energy exist but are much less known. An accurate method to calculate such a lower bound would allow to provide a theoretical error bar for any quantum chemistry method. We have applied variance-like methods to calculate different lower bound energies of a hydrogen atom using Gaussian basis functions. The upper bound energy is found to be always more accurate than the lower bound energies, i.e. closer to the exact energy. The importance of singular points on mean value evaluation of quantum operators has also been brought to attention.The adsorption reactions of atomic fluorine (F) and fluoride (F$^-$) on small lithium clusters Li$_n$ (n=2-15) have been investigated using accurate quantum chemistry ab initio methods. For the smallest system, we have shown that the formation of the stable Li$_2$F and Li$_2$F$^-$ complexes proceeds via a barrierless long-range electron transfer, from the Li$_2$ to F for the neutral and conversely from F$^-$ to Li$_2$ for the anionic system. Such reactions could be fast at very low temperature. Furthermore, the formed complexes show unique long bond characteristics. For the bigger Li$_n$F/Li$_n$F$^-$ systems ($n\geqslant 4$), we have shown that the adsorption energies can be as large as 6~eV depending on the adsorption site and that more than one electronic state is implied in the adsorption process. The formed complexes show interesting "superalkali" properties and could serve as building blocks in the synthesis of charge-transfer compounds with tunable properties
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Grenier, Antonin. "Development of solid-state Fluoride-ion Batteries : cell design, electrolyte characterization and electrochemical mechanisms." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066128/document.
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Les batteries tout-solides à ions fluorures reposent sur l'échange réversible d'ions F- entre un métal et un fluorure métallique au travers d'un électrolyte solide. Ces dispositifs électrochimiques peuvent théoriquement permettre l'obtention de fortes densités énergétiques, bien supérieures à celles des batteries conventionnelles Li-ion commerciales. En conséquence, les batteries à ions F- suscitent un fort engouement. Dans ce contexte, une partie de nos travaux ont portés sur le développement d'une cellule permettant d'évaluer leurs performances. De plus, les propriétés électrochimiques de l'électrolyte solide LaF3 dopé BaF2, La1-xBaxF3-x, ont fait l'objet d'une attention particulière. Finalement, les changements structuraux s'effectuant au sein des électrodes lors des cycles de charge/décharge ont été étudiés afin de mieux comprendre les mécanismes électrochimiques mis en jeuSolid-state fluoride-ion batteries rely on the reversible exchange of the F- ion between a metal and a metal fluoride through a solid electrolyte. These electrochemical devices can theoretically reach energy densities superior to conventional Li-ion commercial batteries. Consequently, fluoride-ion batteries can be seen as a new promising chemistry generating a growing interest. In this context, a part of our work has been dedicated to the development of a cell allowing the evaluation of their electrochemical performance. Moreover, particular attention was given to the electrochemical properties of the solid electrolyte, BaF2-doped LaF3, La1-xBaxF3-x. Finally, the structural changes taking place at the electrodes upon charge/discharge were studied in order to gain insight into the electrochemical mechanisms involved in these devices
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Matsuda, Sandra Satiko. "Efeito diferencial do flúor durante a mineralização de osteoblastos de duas espécies de camundongos com diferentes densidades ósseas." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/25/25142/tde-04072011-114006/.
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O flúor é um elemento natural encontrado em diversas concentrações tanto na água como no solo. É considerado um nutriente benéfico quando presente em níveis ótimos. Apesar de ser utilizado como medicamento em pacientes com osteoporose, sendo capaz de aumentar a densidade óssea, sua eficácia na redução de fraturas ainda apresenta muitas controvérsias, e a exposição a altos níveis e por tempo prolongado, pode levar à fluorose esquelética. Dessa forma o objetivo deste trabalho foi estudar in vitro o efeito do flúor no processo de mineralização por osteoblastos de duas espécies de camundongos com maior e menor densidade óssea, C3H/HeJ (C3) e C57BL/6J (B6) respectivamente. Os osteoblastos isolados da calvária através da digestão enzimática de animais recém nascidos foram expostos a diferentes doses de NaF, e os resultados mostraram que B6 foi mais suscetível ao NaF, apresentando redução da área mineralizada a partir da dose de 10M, enquanto que com C3, a dose significativa foi a partir de 50M, demonstrando que os osteoprogenitores mais diferenciados de C3, são mais resistentes à ação inibitória do flúor. Os testes de unidades formadoras de colônias indicaram um aumento do número de colônias de osteoprogenitores e do número de nódulos mineralizados com a exposição ao NaF. A atividade da metaloproteinase de matriz 2 (MMP-2) também foi aumentada no período de 7 dias em B6 e reduzida nos períodos de 14 e 21 dias em C3, evidenciando que a ação da MMP-2 nestes osteoblastos estão acopladas de forma distinta a diferentes pontos de restrição durante a progressão da diferenciação celular. A dualidade das respostas ao flúor apresentadas pelos modelos experimentais indica que a influência da ação anabólica do flúor, depende do número de alvos em potencial (quantidade de osteoprogenitores presentes na calvária, de células mesenquimais presentes na medula), da atividade intrínseca destes osteoblastos e do estágio de maturação dessas células. Desta forma, a abordagem in vitro fornece insights sobre as bases celulares e moleculares, o que permitirá um melhor diagnóstico e avaliação dos alvos terapêuticos.Fluoride is a natural element found at varying concentrations in drinking water as well as in soil and it is considered a beneficial nutrient at optimal levels. However, although it is well recognized that the fluoride therapy is effective in increasing bone density and it has been used as therapeutic agent to treat osteoporosis, the efficacy in fracture reduction is highly controversial, and exposure to high levels and prolonged time can lead to skeletal fluorosis. The purpose of this study was to investigate the in vitro effects of fluoride exposure during mineralization of two inbread strains, C3H/HeJ (C3) and C57BL/6J (B6), with high and low bone mass respectively. The osteoblasts isolated from newborn mouse calvaria were exposed to several fluoride doses, and the results showed that B6 was more susceptible to NaF, as a reduction in the mineralized area with 10M was already seen; while in C3, the significative dose was with 50 M, indicating that more differentiated osteoprogenitors cells of C3 are more resilient to inhibitory fluoride action. The colony forming unit assays indicate an increase of colony numbers of osteoprogenitors cells and mineralized nodules with NaF treatment. The MMP-2 activity was up-regulated after 7 days of NaF exposure in B6 e down-regulated after 14 and 21 days in C3, showing the distinct coupled action of MMP-2 in different restrictions point during development sequence. The bifasic nature of fluoride responses present by these experimental models indicate that the anabolic action of fluoride is associated to the number of the potential targets (numbers of calvarial osteoprogenitors cells, mesenchymal stem cells), the intrinsic osteoblast activity and the maturation stage of these cells. The cell culture systems can provide molecular and cellular insights, and have the prospective to disclose potential targets and/or better efficacy and safety profile.
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Barbosa, Tatiana de Freitas. "Fluorose dentária e concentração de flúor nas unhas de crianças residentes em diferentes áreas fluoretadas /." Araçatuba : [s.n.], 2010. http://hdl.handle.net/11449/95402.
Full textAbstract:
Orientador: Suzely Adas Saliba MoimazBanca: Doris Hissako Sumida
Banca: Cesar Augusto Casotti
Resumo: A fluoretação das águas de abastecimento público tem ocasionado significante redução na prevalência da cárie em diferentes populações, entretanto, a exposição ao flúor pelo uso de diferentes métodos tem trazido preocupações quanto ao aumento na prevalência de fluorose dentária. Por isso, estudos sobre os fatores de risco associados à fluorose são necessários, além do acompanhamento contínuo e efetivo da exposição ao flúor, por diferentes meios, incluindo mais recentemente os marcadores biológicos para esse íon, como a unha, que também reflete o nível de exposição crônica, desde que um indivíduo tenha uma ingestão de flúor relativamente constante. Assim, objetivou-se analisar o teor de fluoreto das águas de abastecimento público em diferentes áreas de um município, uma abastecida por poços profundos e outra pela estação de tratamento de água (ETA), e verificar se os teores de fluoretos encontrados refletem diferenças nas concentrações de flúor observadas nas unhas das crianças de 12 anos e na prevalência de fluorose dentária. Para isso, foram selecionados 43 pontos para coleta de amostras de água, abrangendo as 17 fontes de abastecimento existente no município. A população de estudo foi constituída por 60 crianças, de 12 anos de idade, nascidas e moradoras permanentes nas duas áreas de estudo, seguindo os critérios de inclusão, sendo uma com excesso e outra sem excesso de flúor nas águas de abastecimento público. As amostras de água, coletadas mensalmente nos pontos previamente estabelecidos, foram analisadas em duplicata no período de janeiro a dezembro de 2009, utilizando-se um analisador de íons acoplado a um eletrodo específico para flúor. Coletas e análise do flúor nas unhas das crianças foram realizadas, utilizando-se a técnica da microdifusão facilitada por HMDS. Para verificação da fluorose... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The fluoridation of public water supply has caused a significant reduction in the prevalence of caries in different populations, however, exposure to fluoride by using different methods has brought concerns about the increasing prevalence of dental fluorosis. Therefore, studies on the risk factors associated with fluorosis are needed, besides the efficient and continuous monitoring of fluoride exposure by various means, including most recently the biological markers for this ion, such as fingernail, that also reflects the level of chronic exposure, as long as an individual has a relatively constant intake of fluoride. The objective was to analyze the fluoride content of public water supply in different areas of a district, one served by deep wells and one by the water treatment station (WTS), and check if the levels of fluoride found reflect differences in the concentrations of fluoride observed in nails of 12 years old children and the prevalence of dental fluorosis. For this, 43 points were selected to collect water samples, covering the 17 existing sources of supply in the municipality. The study population consisted of 60 children, 12 years old, born and permanent residents in both areas of study, following the inclusion criteria, one with and one without too much fluoride excess in public water supply. Water samples collected monthly in points previously established, were analyzed in duplicate in the period from January to December of 2009, using an ion analyzer coupled to a specific electrode for fluoride. Sampling and analysis of fluoride in children nails were done, using the technique of facilitated microdiffusion HMDS. For verification of dental fluorosis we used the modified DEAN index .Of the total samples studied (n=512), 44% (n=224) had adequate levels and 56% (n =288) inadequate levels, and 10% (n=49) lower levels and 46% (n=239) higher... (Complete abstract click electronic access below)
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Capucho, Joffre Luiz Silva. "Síntese da fluorita (CaF2) a partir da solução de fluoreto de amônio (NH4F) obtida como subproduto do processo de produção de dióxido de urânio (UO2)." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/97/97136/tde-25022016-100156/.
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Em uma das etapas do processo de produção do dióxido de urânio, obtém-se como subproduto o fluoreto de amônio em solução. O dióxido de urânio é utilizado na confecção dos elementos que abastecem às Usinas Nucleares.Na unidade fabril da empresa Indústrias Nucleares do Brasil S. A.,esse material sintético é cristalizado em um oneroso e delicado processo de secagem, utilizando grandes equipamentos e considerável quantidade de insumos.A unidade fabril em questão é capaz de produzir anualmente pouco mais de 130 toneladasde fluoreto de amônio seco e a perspectiva atual é favorável à expansão da capacidade instalada. Atualmente, não há destinação final ou aplicação prevista para esse material seco, ou seja, o material é armazenado por tempo indeterminado, onerando ainda mais a produção do combustível nuclear com os custos de manuseio e armazenagem. Este trabalho propõe-se a estudar uma rota alternativapara a síntese da fluorita, ou fluoreto de cálcio (CaF2), a partir da solução de fluoreto de amônio obtida como subproduto do processode produção do Dióxido de Urânio, verificando qual o melhor agente precipitante e estabelecendo as melhores condições para o processo de síntese. A fluorita possui uma vasta aplicação, principalmente nos campos da química, siderurgia e cerâmica. Os melhores resultados foram obtidos utilizando-se calcita (CaCO3) como agente precipitante, mantidas as condições de processo: temperatura (Treação) =70 ºC; tempo de residência (treação) = 2 h e relação estequiométrica entre os reagentes (RE) = 1:1. A calcita foi caracterizada por ICP/OES, difratometria de raios-X (DRX) e microscopia eletrônica de varredura acoplada a espectrômetro de energia dispersiva (MEV/EDS).Os produtos foram caracterizados por DRX e MEV/EDS.At the uranium dioxide production process, ammonium fluoride is obtainedas a byproduct. Uranium dioxide is used at the production of fuel assemblies for Nuclear Mills.At Indústrias Nucleares do Brasil S. A. site, synthetic ammonium fluoride is crystallized in a costly and delicate drying process, which spends importantamounts of supplies. The industrial site in question is able to annually produce over 130 tons ofdryammonium fluoride and the current outlook is favorable to the expansion of installed capacity. Currently, there is no final destination or application provided for this dry material, i.e.,the material is stored indefinitely, further burdening the production of nuclear fuel with the handling and storage costs. This work proposes to study an alternative route for the synthesis of fluorite, or calcium fluoride (CaF2), from ammonium fluoride solution obtained as a by-product of uranium dioxide production process, checkingthe best precipitant agent and establishing the best conditions for the synthesis process.The fluorite has a wide application, particularly in the fields of chemistry, steel and ceramic. The best results were achievedusing calcite (CaCO3) as precipitating agent, keeping the process conditions: temperature (Treação) = 70 ° C; residence time (treação) = 2 h stoichiometric ratio between the reagents (ER) = 1:1.The calcite was characterized by X-ray diffraction (XRD) and scanning electron microscopy coupled with energy dispersive spectrometer (SEM/EDS).The products were characterized by XRD and SEM/EDS.
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Santos, Natanael Barbosa dos [UNESP]. "Avaliação do risco de desenvolvimento de fluorose dentária através da ingestão total de flúor, em crianças de 18 a 36 meses, no município de Penedo - AL." Universidade Estadual Paulista (UNESP), 2006. http://hdl.handle.net/11449/104198.
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A utilização do flúor como medida preventiva e terapêutica tem mudado o perfil da doença cárie dentária, no entanto o aumento da exposição a múltiplas fontes de flúor tem proporcionado uma preocupação constante sobre o aumento da prevalência e severidade da fluorose dentária. O objetivo da presente pesquisa foi analisar a ingestão total de flúor e avaliar o risco de desenvolvimento de fluorose dentária. A amostra foi composta por 55 crianças, de 18 a 36 meses de idade, que freqüentavam as creches (n=25) municipais e outras que residiam em um bairro (n=30) do município de Penedo-Al, tendo o mesmo a água de abastecimento público fluoretada. Foi aplicado, aos pais e/ou responsáveis, um questionário sobre os hábitos de higiene bucal das crianças. Para a análise da ingestão de flúor na dieta, a metodologia aplicada foi a técnica de duplicata da dieta sólida e líquida, durante dois dias consecutivos, enquanto que a ingestão de flúor pelo uso de dentifrício fluoretado foi estimada através da subtração do conteúdo de flúor contido na escova pelo conteúdo de flúor expectorado pela criança. Também foi analisada a regularidade da concentração de flúor adicionada à água da rede pública do referido município. Não existiu diferença significativa em função da ingestão total de flúor entre as crianças da creche e do bairro, respectivamente (lDP) 0,11l0,0463 e 0,09l0,0424 mgF/Kg peso/dia (Teste-t; p>0,05). A quantidade de flúor ingerida na dieta não ultrapassou a dose de risco para o desenvolvimento de fluorose preconizada de 0,05 a 0,07 mgF/Kg peso/dia. A ingestão de flúor através do dentifrício correspondeu a 64,5% do total ingerido nas creches. Fatores como: freqüência de escovação, quantidade de dentifrício colocado na escova, níveis de expectoração e a concentração de flúor solúvel do dentifrício utilizado tiveram correlação...
The use of fluoride as a preventive and as a therapeutic measure has changed the dental caries profile. However, exposure to multiple sources of fluoride and an increase in its consumption has brought about a greater and ongoing concern regarding the increase in the prevalence and incidence of dental fluorosis. The objective of this study were to assess the total fluoride ingestion by small children and the subsequent risk of developing dental fluorosis. Fifty five (55) children aged 18 to 36 months of age took past in this study. From those, 25 were enrolled in a nursery school and 30 were lifelong residents of suburbs of the city of Penedo - AL, Brazil. All children drank tap water from the public water system of Penedo, which is artificially fluoridated. All parents answered a questionnaire about the oral hygiene habits of their children. During two consecutive days all food and water ingested by each child was collected using the duplicated-plate technique. Fluoride ingestion from dentifrice was estimated by subtracting of the fluoride content in the toothbrush plus the child expectorated toothpaste-saliva slurry from the total fluoride contained in amount of toothpaste placed in the toothbrush. Fluoride in the public water system was also analyzed. There was no significant difference in total fluoride ingestion between nursery-enrolled and non-nursery-enrolled children. The meanlSD total fluoride ingestion in both groups were 0.11l0.0463 and 0.09l0.0424 mgF/Kg body weight/day, respectively (t-Test; p>0,05). Fluoride ingestion from diet did not reach the theoretical dose of 0.05-0.07 mgF/Kg body weight/day which is used to determine the risk for dental fluorosis. Fluoride ingestion from dentifrice amounted to 64.5% of total fluoride ingestion by nursery children. Factors such: toothbrushing frequency, amount of toothpaste placed in the toothbrush, quantity expectorated and ...(Complete abstract click electronic access below)
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Ego, Christophe. "Oligo and polyfluorenes of controlled architecture for applications in opto-electronics." Doctoral thesis, Universite Libre de Bruxelles, 2005. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210958.
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Polyfluorenes are polymers with outstanding properties: They are semi-conducting, relatively rigid, quite stable chemically and thermally, easily substituted and therefore potentially soluble in numerous solvents and more importantly, they exhibit blue electro- and photoluminescence. For all these reasons, these polymers are the subjects of numerous academic and industrial researches.The first subject of this work deal with the design, the synthesis and the characterisation of polyfluorenes end-capped with perylene dicarboximide derivatives. These perylene moieties are able to interact by energy transfer under specific conditions of illumination, proximity and orientation. Their observation by single molecule spectroscopy permitted therefore to gain valuable information concerning the three-dimensional folding of single polyfluorene chains. To complete this study, the synthesis and characterisation of a perylene end-capped trimer of fluorene was performed. This structure being monodisperse, a finer analysis of the energy-transfer occurring between both perylene dyes could be accomplished, which confirmed the structural hypothesis made for the polymer. During these studies, it has been observed that, in addition to the energy transfer occurring between both perylene derivatives, another energy transfer occurs between the polyfluorene backbone and the perylene derivatives upon excitation of the first. This led to the idea of the synthesis of a polyfluorene bearing perylenes dicarboximide as side chains. This perylene-rich polyfluorene has been used to build a photovoltaic cell efficient in the wavelengths of both polyfluorene absorption and perylene carboximide absorption.
Another subject of this work was the design, synthesis and characterisation of polyfluorenes bearing bulky phenoxy groups as side-chains. These polymers, due to their lower tendency toward aggregation, exhibited a better stability of their emission colour upon annealing. Similarly, a series of homo- and copolymers of fluorene bearing bulky and hole accepting triphenylamine substituants was synthesised and characterised. In addition to their improved colour stability in comparison with dialkylpolyfluorenes, the LEDs build with these materials exhibited a very low turn on voltage.
Doctorat en sciences, Spécialisation chimie
info:eu-repo/semantics/nonPublished
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Mimouni-Erddalane, Naïma. "Préparation et caractérisation de la zéolithe A et de la sodalite en présence de l'anion fluorure : première obtention de sodalite fluorée." Mulhouse, 1994. http://www.theses.fr/1994MULH0332.
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La synthèse de la zéolithe a en présence de fluorure de sodium a permis soit la cocristallisation de la sodalite fluorée soit l'incorporation de l'anion fluorure dans les cages sodalites de la zéolithe A lorsque cette phase est pure. Par ailleurs, la synthèse de la sodalite en présence de fluorure de sodium a permis pour la première fois l'obtention de la sodalite fluorée complétant la série des halosodalites. La teneur en fluor incorporé dans la sodalite est liée à la quantité d'ions hydroxyde engagée lors de la synthèse. A partir d'une certaine teneur en ions hydroxyde, l'hydroxyfluorosodalite est obtenue où l'anion fluorure a un seul environnement ; sa position dans les cages sodalites est identique à celle des anions halogénure dans les halosodalites. Pour une teneur en ions hydroxyde plus faible, la fluorosodalite est obtenue où l'anion fluorure a deux environnements. Sa position dans les cages sodalites est identique à celle des anions hydroxyde dans l'hydroxysodalite. Elle est fonction de l'hydratation du matériau. Par lavage à l'eau après synthèse une partie des cages sodalites des deux sodalites fluorées se transforme en cages hydrosodalites. Une étude structurale menée à l'aide de la résonance magnétique nucléaire haute résolution du proton 1, du fluor 19, du sodium 23, de l'aluminium 27 et du silicium 29 de ces deux phases est également décrite
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Carvalho, Juliane Guimarães de. "Suscetibilidade genética para fluorose dentária: um estudo metabólico e proteômico com diferentes linhagens de camundongos." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/25/25142/tde-24032010-155218/.
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A fluorose dentária é uma patologia que ocorre durante a formação dos dentes na presença de doses excessivas de fluoreto (F-). Os mecanismos pelos quais o F provoca a fluorose ainda são poucos conhecidos. A influência de fatores genéticos tem sido considerada na suscetibilidade/resistência do indivíduo em desenvolver a fluorose. Duas linhagens de camundongos (A/J e 129P3/J) com diferença na resistência ou suscetibilidade à fluorose dentária foram utilizadas para determinar se a suscetibilidade à fluorose pode ser explicada pela diferença no metabolismo e se há diferença no perfil protéico dos rins e urina destes animais. Para isso, um estudo metabólico foi conduzido com 18 camundongos A/J (suscetível) e 18 129P3 / J (resistente) após o desmame. Cada amostra foi dividida em 3 grupos, com diferentes concentrações de F- na água de beber (0, 10 e 50 ppm F). Uma vez que um estudo piloto revelou que os camundongos A/J ingeriam um maior volume de água quando comparado com o 129P3/J, a concentração de F- na água dada aos camundongos A/J foi ajustada semanalmente a fim de fornecer doses semelhantes de F- para ambas linhagens. Os animais foram mantidos em gaiolas metabólicas (n = 2/gaiola) por 7 semanas, com livre acesso à água e dieta de baixa ingestão de F- (0,95 ppm). A ingestão e excreção de F- foram calculadas, bem como os níveis de F- no plasma, no fêmur e no rim. O grau de fluorose dentária foi avaliado usando análise de fluorescência quantitativa (QLF) e exame clínico. Os perfis proteômicos renal e urinário foram examinados utilizando 2D-PAGE e coloração com azul de Coomassie.. Os dados do estudo metabólico foram testados para diferenças significativas pela ANOVA a 2 critérios (p <0,05). As imagens dos géis e as diferenças estatísticas (ANOVA, p<0,05) foram analisadas pelo programa Image Master Platinum 7.0. Os camundongos da linhagem A/J submetidos à alta concentração de fluoreto apresentaram um grau de fluorose significativamente maior quando comparado com a linhagem 129P3/J. A ingestão total de F- não diferiu significativamente entre as linhagens. A excreção total de F- foi significativamente maior para os camundongos A/J, devido à maior excreção urinária de F-. As duas linhagens não diferiram em relação à absorção F-, mas os animais 129P3/J retiveram significativamente maiores quantidades de F-, que foi consistente com níveis mais elevados de F- no fêmur, no entanto, os níveis de F- no plasma não diferiram significativamente entre as linhagens. Para os rins, a análise quantitativa de intensidade detectou, entre as linhagens A/J e 129P3/J, 122, 126 e 134 spots diferencialmente expressos nos grupos controle, e que receberam baixa e alta concentração de F-, respectivamente. Para a urina, 84 spots diferencialmente expressos foram observados para o grupo controle, 68 para o grupo que recebeu baixa concentração de F- e 66 para o grupo que recebeu alta concentração de F-. Os dados mostraram que há diferenças metabólicas e no perfil de expressão protéica renal e urinária intrínsecas a estas linhagens e que a exposição ao F- é capaz de alterar estes padrões.Dental fluorosis occurs during tooth formation when excessive doses of fluoride (F) are ingested. The mechanisms that underlie the pathogenesis of dental fluorosis are not known so far. The influence of genetic factors has been considered in individual susceptibility/resistance to develop fluorosis. Two inbred mice strains (A/J and 129P3/J) have been reported to have different susceptibilities to dental fluorosis. They were used in the present study to determine if the susceptibility to dental fluorosis can be explained by alterations in F metabolism and to evaluate if there is difference in the profile of protein expression in kidney and urine of these animals. For this, a metabolic study was conducted with 18 A/J (susceptible) and 18 129P3/J (resistant) weanling mice. Each strain was divided into 3 groups, with differed according to the F concentration given in the drinking water (0, 10 and 50 ppm F). Since a pilot study showed that the A/J mice drank a higher volume of water when compared with the 129P3/J, the F concentration in the water given to the A/J mice was weekly adjusted in order to provide similar F intakes for both strains. The mice were housed in metabolic cages (n=2/cage) for 7 weeks, with free access to water and low-F diet (0.95 ppm). F intake and excretion were calculated, as well as plasma, femur and kidney F levels. The degree of dental fluorosis was assessed using QLF and clinical examination. Renal and urinary proteome profiles were examined using 2D-PAGE and coomassie brilliant blue staining. Data were tested for significant differences by 2-way repeated-measures ANOVA (p<0.05). The gels images and statistical differences (ANOVA, p <0.05) were analyzed by the Image Master Platinum 7.0 software. Significantly higher QLF scores were observed for the A/J mice submitted to 50 ppm F. The total F intake did not significantly differ between the strains. The total F excretion was significantly higher for the A/J mice, due to the higher urinary F excretion. The two strains did not differ in respect to F absorption, but the 129P3/J mice retained significantly higher amounts of F, which was consistent with their higher femur F levels. Plasma F levels, however, did not significantly differ between the strains. For kidney, quantitative intensity analysis detected, between strains A/J and 129P3/J, 122, 126 e 134 spots differentially expressed in the control group, in the group receiving low and high F concentrations, respectively. For urine, 84 spots differentially expressed were detected for control group, 68 for the group receiving low F concentration and 66 for the group receiving high F concentration. Data showed that intrinsic differences occur in the metabolism of F and profile of protein expression between these strains and that these profiles can be altered in the presence of F.
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Sousa, Emerson Tavares de. "Biomonitoramento da ingestão de fluoretos em pré-escolares residentes de zona rural com teores residuais de flúor na água." Universidade Federal da Paraíba, 2016. http://tede.biblioteca.ufpb.br:8080/handle/tede/8862.
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This work aimed biomonitoring intake of fluoride in preschool rural residents with residual fluoride levels and non-fluoridated city, estimating the risk of fluorosis and correlating exposure biomarkers. Thirty preschoolers 24-71 months, divided into two groups, one with residents of a rural area with a high concentration of fluoride in the water supply (G1-Brejo das Freiras/ São João do Rio do Peixe-PB) and another representing a city without fluoridation (G2-João Pessoa-PB). The volunteers were monitored for intake (water, solid and liquid diet, and dentifrice) and fluorine retention. The fluorine excretion in 24 hours, and samples fingernails served as biomarker. Comparative analysis, regression and correlation were significant when p ≤ 0.05. The average fluoride intake was 0.18 ± 0.14 (G1) and 0.05 ± 0.04 (G2) mg/kg/day, p <0.05. In G1 there were water contribution in daily intake (0.07 ± 0.1 mg/kg/day), as opposed to G2 determined according to the dentifrice (0.04 ± 0.04 mg/kg/day). Retention was directly proportional to the concentration of fluoride in the water in G1, following the trend of Urinary Excretion Fraction (FUFE), similar in both groups. A correlation between fluoride in the fingernails and toes, and the nails of the feet more sensitive to differences between the groups. It was concluded that there is a high intake of fluoride in the region with residual fluoride levels correlated with sensitivity of biomarkers.
Esse trabalho visa biomonitorar a ingestão de fluoretos em pré-escolares residentes de zona rural com teores residuais de flúor e em cidade não fluoretada, estimando o risco de fluorose e correlacionando à marcadores de exposição. Trinta pré-escolares de 24-71 meses, divididos em dois grupos, um com residentes de uma zona rural com alta concentração de fluoreto na água de abastecimento (G1-Brejo das Freiras/ São João do Rio do Peixe-PB) e outro representando uma cidade sem fluoretação (G2-João Pessoa-PB). Os voluntários foram monitorados quanto à ingestão (água, dieta sólida e líquida, e dentifrício) e retenção de flúor. A excreção de flúor em 24 horas, assim como amostras de unhas serviram como biomarcadores. Análises comparativas, de regressão e correlação foram significantes quando p≤0,05. A ingestão média de fluoreto foi 0,18 ± 0,14 (G1) e 0,05 ± 0,04 (G2) mg/kg/dia, p<0,05. Em G1 há maior contribuição da água na ingestão diária (0,1 ± 0,07 mg/kg/dia), ao contrario de G2, determinado pelo dentifrício (0,04 ± 0,04 mg/kg/dia). A retenção foi diretamente proporcional à concentração de flúor na água em G1, seguindo a tendência da Fração Urinária de Excreção (FUFE), similar nos dois grupos. Observou-se correlação entre o flúor nas unhas das mãos e dos pés, sendo as unhas dos pés mais sensíveis às diferenças entre os grupos. Concluiu-se que há uma elevada ingestão de fluoretos em região com teores residuais de flúor correlacionadas à sensibilidade dos biomarcadores.
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Chin, Joshua Kar Yan. "Methods for carbon-11 and fluorine-18 labeling of peptides as PET radiopharmaceuticals: direct labeling with [11C]methyl triflate on cysteine residues and [18F] fluoride on the cationic silicon-based fluoride acceptor (SiFA)moiety." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=121240.
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Radiolabeled peptides have emerged as an attractive platform for diagnostic and therapeutic oncology. However, the 11C-radiolabeling of peptides for positron emission tomography (PET) has been poorly explored, owing to the relatively short half-life of carbon-11 (t1/2 = 20.3 min), and time-consuming multi-step radiochemical reactions. In addition, 18F-radiolabeling via 18F-19F isotopic exchange on the silicon-based fluoride acceptor (SiFA) platform has been hampered by the significant lipophilicity of the SiFA moiety. Herein is described a novel method for the direct, one-step labeling of peptides at the side-chain of cysteine residues on peptides. A regioselective reaction at cysteine residues in the presence of competing amino acid side-chains is presented. Finally, the radiosynthesis of [11C]Cys(Me)-[Tyr3-octreotate] is undertaken as a demonstration of the applicability of the labeling method for peptides of biological interest. This octreotate derivative was obtained in non-decay-corrected radiochemical yields of 11±2% (n=3) with a synthesis time of approx. 30 min. The quaternary ammonium functional group has been introduced to mitigate the lipophilicity of the SiFA moiety. The design and synthesis of cationic SiFA building blocks bearing functional groups amenable to bioconjugation (-SH, -CHO, -maleimido, -N3, -C≡CH, -CO2H) are presented. These building blocks have been assessed for compatibility in bioconjugation reaction conditions. The resulting cationic SiFA-Tyr3-octreotate conjugates applied to 18F-radiolabeling and lipophilicity assessment by the shake-flask method. These peptide conjugates exhibit reduced lipophilicities (logD7.4 = 0.43 – 2.19). Conjugates containing a hydrophilic PEG linker present (logD7.4 = 0.43 – 0.92) have particularly low lipophilicity as compared to noncationic SiFA-TATE (logD7.4 = 2.68). These results demonstrate the feasibility of labeling bioactive peptides with carbon-11 and fluorine-18 for use as PET radiotracers. These novel methods are characterized by facile one-step labeling conditions at room temperature under short reaction times, on the order of seconds or minutes.L'utilisation de peptides radiomarqués constitue une plateforme de recherche émergente pour le développement de nouveaux outils diagnostiques de même que de nouvelles thérapies en oncologie. Par contre, en raison de sa relative courte demi-vie (t1/2 = 20.3 min) et des réactions de radiochimie impliquant de multiples étapes lui étant associé, le marquage de peptides au carbone-11 pour l'imagerie de tomographie par émission de positons (TEP) demeure largement inexploré. Aussi, le marquage au fluor-18 par échange isotopique 19F-18F suivant la méthodologie SiFA est limité par la lipophilicité marquée du fragment SiFA. Nous décrivons ici une nouvelle méthode, directe et en une seule étape, permettant le marquage au carbone-11 sur la chaine latérale de résidus cytéines au sein de peptides. La faisabilité de même que la régiosélectivité aux résidus cystéines en présence de chaines latérales compétitives seront démontrées. Cette méthodologie est appliquée à la radiosynthèse du peptide d'intérêt biologique [11C]Cys(Me)-[Tyr3-octreotate], lequel est obtenu dans un rendement de 11±2% (n=3) (non-corrigé pour la désintégration) dans un délais d'approximativement 30 min. De plus, l'incorporation de groupements fonctionnels du type ammoniums quaternaires est mise de l'avant comme solution afin d'atténuer la lipophilicité inhérente au fragment SiFA. Ainisi, nous décrivons le design et la synthèse de fragments SiFA cationiques bioconjugables (-SH, -CHO, -maleimido, -N3, -C≡CH, -CO2H). Qui plus est, la compatibilité de ces fragments a été évaluée dans des réactions de bioconjugaison, alors que les dérivés SiFA-Tyr3-octreotate obtenus, ont été radiomarqué au fluor-18 et leur lipophilicité évalué par la méthode shake-flask. Ces peptides conjugués sont caractéristiques d'une lipophilicité réduite (logD7.4 = 0.43 – 2.19), en particulier les dérivés contenant une chaine PEG (logD7.4 = 0.43 – 0.92), comparativement au SiFA-TATE neutre (logD7.4 = 2.68).Considérés dans leur ensemble, ces résultats démontrent la faisabilité des radiomarquages de peptides bioactifs avec des radioisotopes TEP tel que le carbone-11 et le fluor-18. De plus, ces nouvelles approches méthodologiques sont caractérisées par des conditions de radiomarquages favorables: réactions en une étape et à température ambiante de même des temps de réaction de l'ordres quelques secondes à quelques minutes.
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Levy, Flávia Mauad. "Avaliação da ingestão de flúor de crianças brasileiras de 2 a 6 anos de idade." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/25/25142/tde-14042009-163725/.
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Este estudo comparou a ingestão de flúor (F) de crianças de 2 a 6 anos residentes em área fluoretada (Bauru-SP, 0,6-0,8 ppm F) e não fluoretada (Pirajuí-SP), avaliada através do método da dieta duplicada associado à escovação simulada e do Questionário de Freqüência Alimentar semi-quantitativo (QFAsq) associado a questionário para estimativa de ingestão de F a partir do dentifrício. Inicialmente, o QFAsq foi aplicado em 398 crianças residentes no município de Pirajuí-SP. Posteriormente, foram avaliadas subamostras de 25 crianças residentes em Bauru e 24 residentes em Pirajuí. Nestas subamostras, a quantidade de F ingerida através da dieta foi determinada pelo QFAsq e também pela dieta duplicada, considerando seus diferentes constituintes (água, outros líquidos e sólidos). A ingestão de F através do dentifrício foi determinada pelo questionário para estimativa da ingestão de dentifrício e pela escovação simulada. O F foi analisado por eletrodo, depois de difusão facilitada por hexametildiloxano ou após tamponameno com TISAB. A analise estatística foi feita utilizando o software GraphPad InStat, aplicando os testes t pareado, t não pareado, Wilcoxon pareado, Mann-Whitney e estatística de correlação (p<0.05). O QFAsq aplicado à amostra de 398 crianças de Pirajuí encontrou valores de ingestão total de F significativamente menores que os relatados previamente para crianças residentes em Bauru (Miziara, 2006). Na subamostra de crianças avaliadas, a média (±DP, mg) da ingestão de F estimada a partir do QFAsq e da dieta duplicada, considerando-se a dieta total foi de 0,420±0,087 e 0,805±0,190 (Bauru) e 0,227±0,072 e 0,144±0,050 (Pirajuí), sendo a diferença entre os métodos significativa em ambos os municípios. Somente foi obtida uma correlação significativa entre os dois métodos no caso dos sólidos, para ambos os municípios. Considerando a estimativa da ingestão de F a partir do dentifrício obtida pela aplicação do questionário e pela escovação simulada, as médias (±DP, mg) compiladas (Bauru mais Pirajuí) foram 0,611±0,452 e 0,784±0,737, respectivamente, não havendo diferença e nem correlação significativas entre os métodos. Através da utilização dos questionários, foi possível detectar diferença significativa na ingestão total de F entre Bauru e Pirajuí. Entretanto, o mesmo não ocorreu quando se utilizou o método da dieta duplicada associado à escovação simulada. Face aos resultados obtidos, o QFAsq associado a um questionário para estimativa da ingestão de F a partir do dentifrício parece ter um bom potencial para utilização a nível epidemiológico, para se avaliar o risco de grupos de crianças à fluorose dentária. Alguns parâmetros do QFAsq podem ser melhor trabalhados para uma análise mais fidedigna, principalmente com relação à freqüência de ingestão de água e outros líquidos. Em adição, a aplicabilidade desses questionários a nível individual para detecção de risco à fluorose dentária ainda precisa ser melhor estudada.This study compared the fluoride (F) intake of 2-6-year-old children, living in fluoridated (Bauru-SP, 0,6-0,8 ppm F) and non-fluoridated (Pirajuí-SP) areas. The methods used were the duplicate diet associated to simulated toothbrushing and the semi-quantitative food frequency questionnaire (sqFFQ) associated to a questionnaire for estimation of F intake from dentifrice. Initially, the sqFFQ was applied to 398 children living in Pirajuí. In another phase, subsamples of 25 children living in Bauru and 24 living in Pirajuí were evaluated. In these subsamples the F intake from diet was determined using the sqFFQ as well as the duplicate diet method, considering the different constituents of the diet (water, other liquids and solids). The F intake from the dentifrice was determined using the questionnaire for estimation of F intake, as well as simulated toothbrushing. F was analyzed with the electrode, following hexamethyldisiloxanefacilitated diffusion or after buffering with TISAB. For statistical analysis, the GraphPad InStat software was used. The applies tests were paired and unpaired t tests, paired Wilcoxon test, Mann-Whitney test and correlation analysis (p<0.05). The sqFFQ, when applied to the sample constituted by 398 children living in Pirajuí, found values of total F intake significantly lower when compared to previous data reported by Miziara (2006) for children living in Bauru. In the subsample of evaluated children, the mean (±SD, mg) F intakes estimated by the sqFFQ and duplicate diet (total diet) were 0.420±0.087 and 0.805±0.190 (Bauru) and 0.227±0.072 and 0.144±0.050 (Pirajuí), respectively. The difference between the methods was significant for both municipalities. For both municipalities, a significant correlation between the methods was obtained in the case of solids only. Considering the estimation of F intake from dentifrice obtained by the application of the questionnaire and simulated toothbrushing, the compiled (Bauru plus Pirajuí) means (±SD, mg) were 0.611±0.452 and 0.784±0.737, respectively. The difference as well as the correlation between the methods were not significant. By using the questionnaires, it was possible to detect a significant difference in the total F intake between Bauru and Pirajuí. However, the same did not occur when using the method of duplicate diet associated with simulated toothbrushing. Due to the results obtained, it seems that the sqFFQ associated to a questionnaire for estimation of F intake from dentifrice has a good potential for use at epidemiological level in order to evaluate the risk of groups of children to dental fluorosis. Some parameters of the sqFFQ need to be better addressed for a more precise analysis, mainly with respect to the frequency of water and other liquids intake. In addition, the applicability of these questionnaires at the individual level for the detection of risk to dental fluorosis requires further studies.
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Leite, Giselle de Angelo Souza. "Efeitos do chumbo na formação do esmalte fluorótico em ratos." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/58/58135/tde-19032010-112217/.
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A co-exposição ao chumbo e ao flúor pode alterar o grau de fluorose dental, uma vez que ambos se depositam nos tecidos dentais. Ratos Wistar foram separados em 4 grupos: controle e 3 grupos que recebiam água contendo 100ppm de flúor (F), 30ppm de chumbo (Pb), ou 100ppm de F mais 30ppm de Pb desde a gestação. Análise do esmalte e determinação das dosagens de F no esmalte, dentina e osso foram realizadas nos animais com 81 dias. Defeitos nos incisivos dos ratos foram usados como escores em um índice que discriminou lesões na superfície como bandas, ilhas e cavidades. Não houve diferenças nas concentrações de F nos tecidos calcificados entre os grupos F e F+Pb. Os grupos controle e chumbo apresentaram esmalte normal. O grupo F+Pb apresentou defeitos de esmalte mais severos quando comparados com o grupo F (P<0.001). Este estudo mostrou que o Pb exacerbou a fluorose dental em roedores, sugerindo que a co-exposição ao PB pode explicar as diferenças na prevalência de fluorose.Co-exposure to lead and fluoride may alter the degree of dental fluorosis, since both accumulate in calcified tissues. Wistar rats were allocated in four groups: control, and 3 groups that received water containing 100 ppm of fluoride (F), 30 ppm of lead (Pb), or 100 ppm of F and 30 ppm of Pb (F+Pb) since gestational age. Enamel analysis and F determinations in enamel, dentine, and bone were performed in 81-day-old animals. Incisor defects were scored using an index that discriminated surface lesions as bands, islets, and pits. There were no differences in the F concentration in calcified tissues between the F and F+Pb groups. The control and the Pb groups presented normal enamel. The F+Pb group presented more severe enamel defects compared with the F group (P<0.001). This study shows that Pb exacerbates dental fluorosis in rodents, suggesting that co-exposure to Pb may explain differences in fluorosis prevalence.
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Adriano, Maria Soraya Pereira Franco. "Estudo de Biomarcadores em humanos para fluorose óssea." Universidade Federal da Paraíba, 2016. http://tede.biblioteca.ufpb.br:8080/handle/tede/9815.
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Skeletal fluorosis is a chronic metabolic disorder caused by chronic ingestion or inhalation of high concentrations of fluoride. The main consequences are bone alterations and deformities leading to disability. It is a disease of difficult diagnosis because of its pre-clinical signs resembling other bone diseases. In this sense, this epidemiological, observational, transversal and descriptive study aimed at mapping clinical, radiological and molecular biomarkers of exposure. Initially the sample consisted of 103 individuals of both sexes and varied ages. From the total, 45 individuals were analyzed for the identification of the radiological biomarker and 25 individuals were monitored for the biochemical and proteomic markers. For the analysis of fluoride intake in the region, drinking water was collected and the biomarkers were evaluated. As for identification of the samples regarding fluoride exposure: 25 hours urine analysis was performed through the direct method using TISAB II and III on an specific electrode and for the fluoride dosage on fingernail and hair the analysis was done though the indirect method (HMDS). The radiographs were carried out on a Kodak K 9000 C 3d apparatus (by the same operator) with exposure of 16 S, 10 Ma, 60-70 kvp and the maximum skin intake (DEP) of 5 mgy. The volunteers underwent digital panoramic radiographs under same circumstances. For biochemical parameters it was performed a complete blood count, hormonal dosage, calcium and enzymes dosage (creatinine and alkaline phosphatase). For the proteomic identification it was performed a mass spectrophotometry (MALDI-TOF). Data were analyzed on the statistical package for social sciences (SPSS), version 18, using p<0.05. The results pointed out that 46% of the drinking water from São João do Peixe River presented [F] above the ideal value for human consumption of 0.7mg/L and 84% showed values above 1.5mg/L, being indicative of fluorosis in the region. The average age of the volunteers was 50 years, with the prevalence of women, and they showed a time of exposure around 40 years. Regarding the symptomatology 85 individuals reported pain, of which 77% (chi-squared) presented symptoms on more than 3 regions. However, the lumbar region was the indicative variable of presence of bone fluorosis (linear regression, p < 0.005). As for the radiological biomarker, it was verified that the most discriminatory bone conditions were osteopenia, ossification of soft tissues, bone deformit ies, jaw density, and thin cortical of jaw and jaw. There was evaluation divergence between orthodontists and radiologist. Panoramic radiographs proved to be an auxiliaar method of diagnosis and can only be an indicative of bone changes related to skeletal fluorosis, it cannot be discriminatory in cases of grades I and II skeletal fluorosis. The biochemical variables showed that the average volume of urine excreted was 890 ml in 24 hours, whose concentration contained an average of 3.9 mgF/liter (0.2-3.2 VR), presenting a high fluoride excretion. The average fluoride concentration on fingernails was 14.2 being the highest level ever recorded, probably due to the diffusion capture of F by the HMDS. Serum calcium had an average of 9.0 mg/dl (8.9 -10, 3VR); phosphorus, 3.8 mg/dl (2.4-4.7 VR); alkaline phosphatase, 288 IU/litre (32-91 VR); Alkaline phosphatase bone specific, 96 ug/litre (4.5-16.9 VR); Osteocalcin, 309 ng/ml (11-50 VR); and PTH, 203 pg/ml (10-65 VR). Electrolytes, glucose, albumin, urea and creatinine were with 70% normal, as well as platelet count. Among the sick and non-patient studied groups, there were no differences between the groups, according to the Mann-Whitney test, p < 0.05. For proteomics analysis, there was a large quantity of proteins in the serum, being the affected volunteers more altered when compared to the other group. Few proteins were found on the saliva. Data indicate that mass spectrophotometry is capable of detecting differential proteins so it can be useful for fluoride biomarkers identification as well as it can help understand the skeletal fluorosis mechanism.
A fluorose ó ssea é uma doença metabólica crônica, causada pela alta concentração do flúor ingerido ou inalado. Tem como principal consequência alterações e deformidades ó sseas levando a incapacidade. Mordidade de difíc il diagnó stico, devido aos sinais pré- clínicos assemelhar-se a de outras doenç as ó sseas, gerando problemas para a realizaç ão do diagnó stico. Neste sentido, este estudo epidemiológico, observacional, transversal e descritivo teve como objetivo mapear biomarcadores de exposiç ão, clínicos, radiológicos e moleculares para fluorose ó ssea . A amostra constitui inicialmente de 103 indivíduos de ambos os sexos e variadas faixas etárias. Sendo 45 analisados quanto a identificaç ão do biomarcador radiológico e 25 monitorados quanto ao marcador bioquímico e proteô mico. Para investigaç ão das concentraç ões de ingestão de flúor na região foi realizada a coleta de água para consumo e para identificaç ão das amostras quanto a exposiç ão ao fluoreto foram avaliados os biomarcadores: urina (25 horas) ambos realizado através do método direto com TISAB II e III respectivamente e a dosagem da unha e cabelo, pelo meio indireto por difusão com hexametildisiloxano (HMDS). As radiografias foram realizadas em aparelho Kodak K 9000 C 3D (pelo mesmo operador) com exposiç ão de 16 s, 10 mA, 60- 70 Kvp e dose de entrada de pele (DEP) máxima de 5 mGy. Os indivíduos foram submetidos a radiografias panorâ micas (digital) em aparelhos de RX do mesmo modelo e em condiç ões similares. Para os parâ metros bioquímicos foram realizados hemograma completo, dosagem hormonal, dosagem de cá lcio e enzimologia (creatina e fosfatase alcalina). Para identificaç ão de proteomas utilizou-se espectometria de massa (MALDI- TOF). Os dados foram avaliados por meio do Programa Statistical Package for Social Sciences (SPSS) versão 18, com p<0,005. Os resultados apontaram que 46% da água presente em poç os artesianos em São João do Rio do Peixe-PB, apresentam [F] acima do valor ideal de 0,7mg/L para ingestão de água para consumo humano e 84% aponta valores acima de1,5mg/L, sendo indicativo de fluorose na região. A média de idade foi de 50 anos, com predomínio de mulheres, a amostra apresentou um tempo de exposiç ão em torno de 40 anos. Quanto a sintomatologia 85 relataram dor, destes 77% (qui-quadrado), apresentam mais de 3 regiões acometidas. Porém a região lombar foi a variável indicativa de presenç a de fluorose ó ssea (regressão linerar, p<0,005). No que concerne o biomarcador radiológico, verifica-se que as condiç ões ó sseas mais discriminantes: osteopenia, ossificaç ão dos tecidos moles, deformidades ó sseas, densidade da maxila, e cortical fina de maxila e mandíbula. Houve divergê ncia na avaliaç ão entre ortodontistas e radiologias. A radiografia panorâ mica se mostrou como um recurso auxiliar e apenas indicativa de alteraç ões ó sseas relacionadas com a fluorose ó ssea, não podendo ser discriminató ria nos casos de fluorose ó ssea de graus I e II. Quanto as biomarcadores de exposiç ão foi evidenciado. As variáveis bioquímicas que o volume médio excretado foi de 890 ml em 24 h, cuja concentraç ão continha uma média de 3,9 mg / litro F (0,2-3,2 VR), constatando uma excreç ão elevada. A concentraç ão média da unha encontrado foi de 14,2 sendo o mais elevado nível de concentraç ão já registrada, provavelmente devido à captura de difusão de F pelo HMDS.Cá lcio sérico teve uma média de 9,0 mg / dl (8,9-10,3VR); fó sforo, 3,8 mg / dl (2,4-4,7 VR); fosfatase alcalina, 288 UI / litro (32-91 VR); específica do osso da fosfatase alcalina, 96 ug / litro (4,5-16,9 VR); osteocalcina, 309 ng /ml (11-50 VR); e PTH, 203 pg/ml (10-65 VR). Eletró litos, glicose, albumina, uré ia e creatina estavam com 70% normais, assim como contagem de plaquetas. Entre os grupos estudados doentes e não doentes, não houve diferenç as entre os grupos, segundo o teste de Mann-Whitney, p<0,05. Para aná lise proteô mica, verificou-se a presenç a de uma grande quantidade de proteínas no soro, estando os doentes mais alterado quando comparado com o outro grupo. A saliva poucas proteínas foram encontradas. Os dados indicam que a espectometria de massa é capaz de detectar proteínas diferecialmente expressa. Podendo ser útil para identificaç ão de biomarcadores para F, além de ajudar no avanç o do mecanismo envolvido da fluorose ó ssea.
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Pagliari, Ana Valéria. "Análise da concentração de íon flúor em leite em pó /." Araçatuba : [s.n.], 2004. http://hdl.handle.net/11449/95420.
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Orientador: Suzely Adas Saliba MoimazResumo: O leite materno é, indiscutivelmente, o alimento ideal para os primeiros meses de vida da criança, mas existem situações que impossibilitam ou dificultam seu consumo. Nestes casos, fórmulas infantis, leite de vaca integral diluído e leite de soja podem ser oferecidos. Este trabalho pretende avaliar o leite como contribuinte para a ingestão diária de flúor em crianças e como fator de risco para o desenvolvimento de fluorose dentária. A primeira parte procura estimar esta contribuição, partindo da concentração de flúor no leite humano, leite de vaca, leite em pó e fórmulas infantis, encontrada em pesquisas publicadas. Os resultados indicam que os leites materno e de vaca in natura não oferecem risco ao desenvolvimento de lesões de fluorose dentária esteticamente inaceitáveis em dentes decíduos ou permanentes, o mesmo ocorrendo para a ingestão de leite em pó quanto aos dentes permanentes. Já as fórmulas infantis e o leite em pó, comercializados no Brasil, preparados em água com concentração ótima de flúor (0,7 mg/L), podem contribuir com uma ingestão diária de flúor acima do limite considerado seguro, podendo provocar o aparecimento de lesões de fluorose em dentes decíduos. A segunda parte deste trabalho teve como objetivos determinar os teores de flúor de fórmulas infantis (n=7), leites (n=10) e leites de soja (n=3), em pó, produzidos em território nacional e adquiridos em Araçatuba-SP e avaliar a possibilidade de desenvolvimento de fluorose dentária, esteticamente inaceitável, com o consumo destes produtos. As amostras de pó foram reconstituídas em água deionizada e analisadas em duplicata pelo método eletrodo específico, após difusão facilitada por hexametildisiloxano... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Mother's milk is, unquestionably, the ideal food for children's first months of life, however, there are situations that make its consumption impossible. In these cases, infant formulas, cow's diluted whole milk and soy-milk can be offered. This paper intends to evaluate milk as a contributor for children's daily fluoride ingestion and as a risk factor to develop dental fluorosis. The first part estimates this contribution by the fluoride concentration of human milk, in natura cow's milk, powder-milk, infant formulas obtained from publications specialized on the subject. The results indicate that that human milk and in natura cow's milk do not offer risk to the development of esthetically unacceptable lesions of dental fluorosis in deciduous or permanent teeth, the same occurring with powder-milk ingestion for the permanent teeth. The infant formulas and powder-milk commercialized in Brazil, prepared in water with optimal fluoride concentration (0.7 mg F/L) can contribute to daily fluoride ingestion above the limit considered as safe for the development of fluorosis in deciduous teeth. The second part of this paper had the purpose to determine the fluoride content in infant formulas (n=7), powder-milk (n=10) and soy-milk (n=3) produced in the national territory and acquired in Araçatuba - SP, and evaluate the possibility to develop esthetically unacceptable dental fluorosis by consuming these products. The powder samples were reconstituted in deionized water and doublechecked through the potentiometrical method after hexametyldisiloxane facilitated diffusion... (Complete abstract, click electronic access below)
Mestre
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Santos, João Vitorino Ribeiro Faria dos. "Flúor: da prevenção à doença." Master's thesis, [s.n.], 2015. http://hdl.handle.net/10284/5279.
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Projeto de Pós-Graduação/Dissertação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Medicina DentáriaO flúor ganhou relevo na medicina dentária no século XX, quando se relacionou o consumo de águas fluoretadas com o surgimento de manchas opacas e a pouca prevalência de cárie. O flúor tem uma ação cariostática que é conseguida pela inibição do processo de desmineralização, a potenciação da remineralização e a inibição da placa bacteriana. Existem diversas formas de admnistração do flúor, podendo ser feita de forma sistémica e de forma tópica. Contudo, quando o flúor é admnistrado em doses excessivas podem surgir efeitos adversos como a fluorose. A fluorose é uma doença que surge na fase de odontogénese e deve-se ao consumo excessivo de flúor. A ocorrência da doença acontece com mais frequência no intervalo de tempo do nascimento até aos 7 anos de idade. Os sinais clínicos da fluorose podem ir de linhas brancas finas até manchas castanhas e são classificadas por índices, como o de Dean e Thylstrup y Fejerskov. A correção destas manifestações clínicas pode ir desde tratamentos conservadores, até tratamentos mais invasivos, dependendo da profundidade das lesões. São exemplos destes tratamentos o branqueamento dentário, microabrasão do esmalte e as facetas. O objetivo deste trabalho foi abordar os aspectos e bases fundamentais referentes ao ião flúor, seus mecanismos de acção e formas de administração e à fluorose dentária,determinando as causas da doença, fazer o seu diagnóstico e escolher o plano de tratamento ideal. Para tal, foi feita uma pesquisa de artigos científicos, revistas científicas, utilizando-se os motores de busca PubMed, Science Direct, Dentalaegis, e livros cujo o limite temporal recaiu entre 1973 e 2015. Concluíndo, o uso irracional do flúor pode causar o aparecimento da Fluorose Dentária, devendo então fazer-se um bom esclarecimento da população a fim de se diminuír o número de casos da doença.
Fluoride first attracted attention in the 20th Century when researchers associate the consume of fluoridated water with white marks on the teeth and the low prevalence of dental caries. Fluoride has a cariostatic effect which stops demineralization and increases remineralization. We can deliver fluoride to the teeth, topically or systemically, and it can become risky for our health. A major cause of fluorisis is the inappropriate use of fluoride-containing dental products. Fluorosis appears during odontogenesis, sometimes children enjoy so much the taste of fluoridated toothpaste that swallow it instead of spitting it out. It can develop during the first seven years of life by overexposure to fluoride. The teeth or those affected by fluorosis may appear middly discolored. For instance, there may be lacy white markings and in more severe cases, the teeth may have stains ranging from yellow to dark brown, surface irregularities and pits that are highly noticeable. Those changes are classified by índices as the Dean and the Thylstrup y Fejerskov. The fluorosis treatments can be more conservatives or more invasive, it will depend on the fluorosis gravity. There are some techniques such as tooth whitening and other procedures to remove surface stains microabrasion and dental veneers. The aim of this work was to approach fluor ion’s characteristics, action mechanisms and administration ways as fluorosis’s causes, symptoms, treatments and prevention. The research set off cientific magazines and articles using search engines as PubMed, Science Direct, Dentalaegis and books from 1973 to 2015. In the end is clear that irrational fluoride use can cause fluorosis that is why population must be well informed to prevent this disease.
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Stanek, Christopher Richard. "Atomic scale disorder in fluorite and fluorite related oxides." Thesis, Imperial College London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.406946.
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Vasdev, Neil Chirakal R. V. Schrobilgen G. J. "Syntheses of fluorine-18 labelled compounds and radiopharmaceuticals by electrophilic fluorination /." *McMaster only, 2003.
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Pai, Nita. "Comparative fluoride uptake into enamel from various topical fluoride agents /." Title page, table of contents and summary only, 1996. http://web4.library.adelaide.edu.au/theses/09DM/09dmp142.pdf.
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Akkoyun, Meral. "Compréhension du phénomène d’adhésion d’un gel polymère réalisé par extrusion sur substrat aluminium : application au contact électrode-collecteur d’une supercapacité." Thesis, Saint-Etienne, 2012. http://www.theses.fr/2012STET4026.
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L’objectif de ce travail est d'envisager les modifications de formulation ou de procédé dans la technologie de geltrusion développée par Batscap pour augmenter la fiabilité des supercondensateurs en limitant l'autodécharge. La technologie repose sur l’extrusion simultanée de polymères (PVDF, PVDF-HFP), d’un solvant (PC) et de charges (CA, NC). Le mélange réalisé en extrusion bivis est ensuite filmé et laminé sur le collecteur en aluminium. Dès lors, il a été fondamental de chercher à comprendre les interactions entre les différents composants de l’électrode, avec l’étude de la miscibilité du système ternaire polymère/polymère/solvant puis l’étude de l’adsorption du solvant sur les charges. Cette démarche a permis une meilleure compréhension des phénomènes impliqués en passant par une caractérisation approfondie du complexe, dans sa formulation actuelle aux différentes étapes du procédé. Ensuite, des modifications de formulations ont été envisagées. En particulier, l'effet de la structure et de la masse molaire des polymères sur l’adhésion a été étudié. Dans tous les cas, il a été envisagé de tester les possibilités offertes par l'utilisation d'un solvant différent (DMSO). Ce dernier étant un meilleur solvant du PVDF est plus facile à éliminer que le PC. Enfin, à partir des données rhéologiques du mélange, une modélisation mécanique, en utilisant le modèle de Maxwell à plusieurs temps de relaxation, a été menée dans l'opération de laminage du mélange en prenant en compte un comportement viscoélastique du gel. Toutes ces études ont permis de conclure sur les modifications pertinentes de la formulation ainsi que des conditions du procédéThe objective of this work is to consider changes in formulation or process of the geltrusion technology developed by Batscap to increase the reliability of supercapacitors by limiting self-discharge. The technology is based on the simultaneous extrusion of polymers (PVDF, PVDF-HFP), solvent (propylene carbonate) and fillers (activated carbon, carbon black). The mixture carried out in a twin-screw extrusion is then filmed and laminated on the aluminium collector. Therefore, it was important to understand the interactions between the different components of the electrode, and especially to study the miscibility of the ternary system polymer/polymer/solvent and also the adsorption of solvent on fillers. This approach has allowed a better understanding of the phenomena involved through a characterization of the complex, in its current form at different stages of the process. Then, changes in formulations were considered. In particular, the effect of the structure and molecular weight of the polymers on adhesion was studied. In all cases, it was envisaged to test the possibilities offered by the use of a different solvent (dimethyl sulfoxide). The latter being a better solvent for the PVDF, is also easier to remove than propylene carbonate. Finally, from the rheological data of the mixture, a mechanical modeling, using the multimodal Maxwell model, was conducted in the lamination step taking into account of the viscoelastic behavior of the gel. All these studies allow us to conclude on the relevant changes in the formulation and process conditions
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Benham, Emmanuel Jakob. "Actinide chemistry : high oxidation-state uranium fluoride and fluoride halide complexes." Thesis, University of Leicester, 1992. http://hdl.handle.net/2381/33962.
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The preparation of UF5 has been re-investigated in detail and it has been shown that the most reliable synthetic route is a novel reaction in which UF6 is interacted with hexamethyldisiloxane at room temperature. The pure UF5 produced has been employed in an investigation of the reactions of UF5.nCH3CN and UF5.nTPPO with trimethylsilylchloride which have been claimed to yield compounds of the type UFxC15-x.nCH3CN (0?x?5 and n = 1,2) and UFxC15-x.nTPPO (TPPO = (C6H5)3PO, 0?x?5 and n = 1,2). In the process of these studies a large number of products were obtained as single crystals and the single-crystal X-ray structures of the novel compounds, [UF4.TPPO]2F, [(UF3.3TPPO)2]2+ 2[UF6]-, cis-UO2Cl2.2TPP0 and ?-trans- UO2Cl2.2TPPO have been obtained. Attempts have been made to elucidate the infrared and e.s.r. spectra of these compounds in order to try to understand the nature of the chemical reactions which give rise to them. Efforts to prepare a mixed bromide fluoride of uranium (VI) have yielded only uranium pentafluoride or uranium tetrafluoride. The preparations of UF5.SbF5.L (L = CH3CN and TPPO) and UF5.2SbF5.5CH3CN were repeated and single crystals were successfully grown for X-ray examination. An attempt to obtain the novel UF5.2SbF5.5TPP0, however, gave inconclusive results.
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Sarthou, Julia. "Etude et caractérisation de céramiques transparentes fluorées pour lasers de forte puissance moyenne." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066534/document.
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Ce travail de thèse a pour objectif d'étudier et de mieux comprendre les relations structure-propriétés de céramiques transparentes Yb:CaF2 obtenues par voie humide, en particulier sur le plan des propriétés thermiques. Dans un premier temps nous présentons les atouts des céramiques transparentes Yb:CaF2 dans le cadre d'une application en laser de puissance. Le procédé de fabrication par voie humide des céramiques est ensuite décrit au cours d'une seconde partie. Les résultats d'analyses et caractérisations diverses ayant eu lieu à différentes étapes de la synthèse des céramiques sont présentés, menant à une optimisation du procédé de fabrication. Un troisième chapitre est ensuite consacré à une étude expérimentale des propriétés thermiques de nos céramiques, qui montre en particulier une grande similitude avec les propriétés des monocristaux. Cette étude est complétée par un volet de modélisation décrit dans un quatrième chapitre. Deux modèles prédictifs de conductivité thermique sont explorés et comparés, et permettent d'apporter une explication théorique aux tendances observées expérimentalement. L'hypothèse selon laquelle l'impact des joints de grains sur la diminution de la conductivité thermique est négligeable devant celui du dopage est notamment confirmée. Enfin, dans une cinquième et dernière partie, plusieurs pistes sont explorées afin d'apporter une explication à l'échauffement supérieur des céramiques par rapport aux monocristaux observé en conditions laserThis PHD work is aiming at getting a better understanding of the structure-properties relationships of Yb:CaF2 transparent ceramics obtained with a wet-route fabrication process, with a special focus on thermal properties. At first, we introduce the assets of Yb:CaF2 transparent ceramics in the frame of high-power laser applications. The wet-route fabrication process is then described in a second chapter. The results of several analysis and characterizations performed along different steps of the ceramics synthesis are also presented, leading to an optimized fabrication process. The third chapter then focuses on an experimental study of the thermal properties of our ceramics, which shows in particular an important similarity with single crystals properties. This study is complemented with a modelization work described in chapter four. Two predictive models of thermal conductivity are investigated and compared. They bring a theoretical explanation to the tendencies experimentally observed. We thereby confirm the hypothesis according to which the grain boundaries impact on thermal conductivity is negligible with respect to that of the doping element introduction. Finally, in the fifth and last chapter, several hypothesis are investigated in order to bring an explanation to the ceramics overheating observed in laser conditions, which is superior to single crystals
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Pagliari, Ana Valéria [UNESP]. "Análise da concentração de íon flúor em leite em pó." Universidade Estadual Paulista (UNESP), 2004. http://hdl.handle.net/11449/95420.
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Fundação para o Desenvolvimento da UNESP (FUNDUNESP)
O leite materno é, indiscutivelmente, o alimento ideal para os primeiros meses de vida da criança, mas existem situações que impossibilitam ou dificultam seu consumo. Nestes casos, fórmulas infantis, leite de vaca integral diluído e leite de soja podem ser oferecidos. Este trabalho pretende avaliar o leite como contribuinte para a ingestão diária de flúor em crianças e como fator de risco para o desenvolvimento de fluorose dentária. A primeira parte procura estimar esta contribuição, partindo da concentração de flúor no leite humano, leite de vaca, leite em pó e fórmulas infantis, encontrada em pesquisas publicadas. Os resultados indicam que os leites materno e de vaca in natura não oferecem risco ao desenvolvimento de lesões de fluorose dentária esteticamente inaceitáveis em dentes decíduos ou permanentes, o mesmo ocorrendo para a ingestão de leite em pó quanto aos dentes permanentes. Já as fórmulas infantis e o leite em pó, comercializados no Brasil, preparados em água com concentração ótima de flúor (0,7 mg/L), podem contribuir com uma ingestão diária de flúor acima do limite considerado seguro, podendo provocar o aparecimento de lesões de fluorose em dentes decíduos. A segunda parte deste trabalho teve como objetivos determinar os teores de flúor de fórmulas infantis (n=7), leites (n=10) e leites de soja (n=3), em pó, produzidos em território nacional e adquiridos em Araçatuba-SP e avaliar a possibilidade de desenvolvimento de fluorose dentária, esteticamente inaceitável, com o consumo destes produtos. As amostras de pó foram reconstituídas em água deionizada e analisadas em duplicata pelo método eletrodo específico, após difusão facilitada por hexametildisiloxano...
Mother's milk is, unquestionably, the ideal food for children's first months of life, however, there are situations that make its consumption impossible. In these cases, infant formulas, cow's diluted whole milk and soy-milk can be offered. This paper intends to evaluate milk as a contributor for children's daily fluoride ingestion and as a risk factor to develop dental fluorosis. The first part estimates this contribution by the fluoride concentration of human milk, in natura cow's milk, powder-milk, infant formulas obtained from publications specialized on the subject. The results indicate that that human milk and in natura cow's milk do not offer risk to the development of esthetically unacceptable lesions of dental fluorosis in deciduous or permanent teeth, the same occurring with powder-milk ingestion for the permanent teeth. The infant formulas and powder-milk commercialized in Brazil, prepared in water with optimal fluoride concentration (0.7 mg F/L) can contribute to daily fluoride ingestion above the limit considered as safe for the development of fluorosis in deciduous teeth. The second part of this paper had the purpose to determine the fluoride content in infant formulas (n=7), powder-milk (n=10) and soy-milk (n=3) produced in the national territory and acquired in Araçatuba - SP, and evaluate the possibility to develop esthetically unacceptable dental fluorosis by consuming these products. The powder samples were reconstituted in deionized water and doublechecked through the potentiometrical method after hexametyldisiloxane facilitated diffusion... (Complete abstract, click electronic access below)
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Camara, Danielle Mendes da [UNESP]. "Avaliação in vitro da eficácia de dentifrícios de baixa concentração de fluoreto suplementados com hexametafosfato sobre o processo de desmineralização do esmalte." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/95446.
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Formulações de dentifrícios com concentrações reduzidas de fluoreto (F) têm sido estudadas para diminuir o risco de fluorose dentária. O objetivo do trabalho foi avaliar a eficácia de dentifrícios com concentrações reduzidas de F (250 μgF/g), suplementados com hexametafosfato (HMP) sobre a desmineralização do esmalte de dente bovino. Blocos de esmalte foram submetidos a repetidas ciclagens de pH alternadas com tratamentos (2x/dia) com dentifrícios sem F contendo HMP nas concentrações de 0, 0,25, 0,5, 1,0, 2,0 e 3,0%, dentifrícios com 250 gF/g suplementados com HMP nas mesmas concentrações, placebo (sem F e HMP), um com 500 μgF/g, outro com 1100 μgF/g e um comercial (Crest, de 1100 gF/g). Após as ciclagens determinou-se a dureza de superfície final (SHf), perda integrada de dureza de subsuperfície (ΔKHN) e o conteúdo de F no esmalte. Os resultados foram submetidos à ANOVA e teste de Bonferroni (p<0.05). O grupo 250 gF/g com 0,5% de HMP apresentou maior valor de SHf, e menor ΔKHN, seguido do grupo de 250 gF/g com 1,0% de HMP que ficou semelhante ao 1100 gF/g e Crest. HMP não interferiu na incorporação de F pelo esmalte em concentrações menores que 3%. Além disso, a adição de 0,5% de HMP a um dentifrício sem F causou um aumento de SHf e uma redução de ΔKHN em comparação ao placebo. Conclui-se que é possível reduzir a concentração de F a 250 gF/g e se obter uma ação comparável de um dentifrício comercial sobre a desmineralização do esmalte bovino através da suplementação com hexametafosfato nas concentrações de 0,5 e 1%
Formulations of dentifrices with reduced concentrations of fluoride (F) have been studied to decrease the risk of dental fluorosis. The aim of this study was to evaluate the efficacy of dentifrices with low concentration of F (250 μgF/g), supplemented with hexametaphosphate (HMP) on the demineralization of bovine tooth enamel. Blocks of enamel were submitted to repeated pH cyclings alternated with treatments (2x/day) with dentifrices without F or containing 250 gF/g supplemented with HMP at concentrations of 0, 0,25, 0,5 1,0, 2,0 e 3,0%, dentifrices supplemented with HMP the same concentrations, placebo (without F and HMP), a dentifrice with 500 μgF/g, another with 1100 μgF/g and a commercial dentifrice (Crest, 1100 gF/g). After cycling, the following analysis were conducted: final surface hardness (SHf), subsurface hardness integrated loss (ΔKHN) and the content of F on enamel. The results were submitted to variance analysis and Bonferroni test (p<0.05). The group of 250 gF/g with 0,5% HMP showed the highest SHf value and the lowest ΔKHN value, followed by the group supplemented with 1,0% HMP which was similar to 1100 gF/g and Crest groups. HMP did not impair the uptake of F by enamel at concentrations lower than3%. Furthermore the addition of 0,5% HMP to a non fluoridated dentifrice caused a rise on SHf and a decrease on ΔKHN in comparison to placebo. It was concluded that it is possible to reduce the concentration of F to 250 μgF/g and obtain an action similar to a commercial dentifrice on the demineralization of enamel by supplementation with hexametaphosphate in concentrations of 0.5 and 1%
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Robison, Robert Russell. "Simulation of fluorine-diffusion behavior and boron-fluorine co-interaction in silicon." [Gainesville, Fla.] : University of Florida, 2006. http://purl.fcla.edu/fcla/etd/UFE0013790.
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Mabire, Anne B. "Fluorescent probes for stimuli-responsive polymers : to fluoresce, or not to fluoresce?" Thesis, University of Warwick, 2017. http://wrap.warwick.ac.uk/98100/.
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This thesis explores the use of aminobromomaleimide and dithiomaleimide functionalities to probe their environment. These fluorescent functionalities were incorporated into responsive polymeric nanostructures allowing their behaviour to be read-out upon external stimuli. Chapter 1 gives a brief introduction on nanoparticles formation and the polymerisation techniques used throughout the thesis. The properties of bromo- and thio-maleimides and their use in protein and polymer chemistry were also introduced. Chapter 2 describes a morphology transition simultaneously with a fluorescence on-to-off switch as a result of the modification of the dithiomaleimide substituent. Chapter 3 presents the synthesis of a library of aminomaleimides and explores their fluorescent properties. In Chapter 4, the fluorescent properties of aminobromomaleimide were incorporated into CO2-responsive polymeric nanoparticles for a built-in read-out of the CO2-response. Chapter 5 explores the possibility of using the fluorescent properties of aminobromomaleimide to read-out the behaviour of glutathione-responsive particles.
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Hansen, Lisa, and Alexander Stime. "Oral fluoride retention after use of mouth rinses with different fluoride content." Thesis, Malmö universitet, Odontologiska fakulteten (OD), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-19945.
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AbstractObjective: The purpose of the study is to investigate how fluoride content in saliva depends on different fluoride mouth rinses: 1450 ppm, 910 ppm, 225 ppm and to compare a new 1450 ppm fluoride mouth rinse with the other concentrations. Material and method: The study included 17 subjects which rinsed with three different mouth rinses, A (225 ppm), B (1450 ppm) and C (910 ppm) at three different times. They rinsed for 1 minute and then spat out all content in a container. After different intervals they passively transferred their saliva into a given container for 1 minute. The samples were sealed and stored in a freezer until the time of analyzing. After the trial, the samples were taken out of the freezer and were reheated. They were mixed with TISAB III and measured with an ion specific electrode. The group’s values were compared by analyzing the results using Tukey’s test.Results: A visible difference between the three mouth rinses were detected, however, only the difference between mouth rinse A and B were deemed statistically significant at all time points. A statistical significant difference between mouth rinse B and C were found at the time point of 45 minutes. Conclusion: There is a statistical significant difference between the new, high fluoride containing mouth rinse B and mouth rinse A, but there is not enough data in the study to see a statistically significant difference between mouth rinse B and C, or A and C. Further studies need to be made.
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Okamoto, Hideyuki. "Studies on Visible Fluoride Fiber Lasers and White Light Emitting Fluoride Glasses." 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/188543.
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Abid, Walha Imen. "Aldolisation des alpha-trialkylsilyl-alpha-diazoacétones induite par l'ion fluorure." Thesis, Le Mans, 2017. http://www.theses.fr/2017LEMA1004/document.
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Les composés diazocétoniques sont des intermédiaires utiles en synthèse organique et l’élaboration de motifs diazocarbonylés est à ce titre un enjeu important. Les diazocétones terminales peuvent subir une addition sur des aldéhydes dans des conditions basiques pour conduire de façon convergente à des composés béta-hydroxy-alpha-diazocétoniques à fort potentiel synthétique. Dans ce contexte, notre projet visait à promouvoir ce type de réaction dans des conditions douces et peu basiques. La stratégie adoptée reposait sur l’utilisation des alpha-trialkylsilyl-alpha-diazoacétones et leur activation nucléophile spécifique par un ion fluorure. Dans un premier temps, la synthèse de la TES-diazoacétone a été optimisée, puis une étude approfondie des paramètres réactionnels a permis la mise au point de la réaction d’aldolisation de la TES-diazoacétone, induite par le TBAF. Deux protocoles expérimentaux faciles de mise en œuvre ont ainsi été mis en place pour conduire à une large gamme de béta-hydroxy-alpha-diazoacétones avec des rendements élevés. L’extension asymétrique de cette méthodologie a ensuite été étudiée en mettant en jeu un fluorure d’ammonium chiral dérivé d’alcaloïde de Cinchona conduisant à la formation des premières béta-hydroxy-alpha-diazoacétones énantioenrichies (e.e = 35%) avec des rendements élevés. Enfin, cette méthodologie a été étendue avec succès à la TIPS-diazoacétone. La robustesse du groupement protecteur TIPS permet d’envisager une large gamme de transformations synthétiques « methyl-side », sans induire une désilylation partielle de la position azométhine du diazo-aldol. Ceci ouvre la voie à l’exploration future de la réactivité des diazoaldols TIPSDiazoketones are valuable intermediates in organic synthesis and the elaboration of α-diazocarbonyl scaffolds has aroused a steady interest for many years. The terminal diazoketones can be added to aldehydes under basic conditions to produce beta-hydroxy-alpha-diazoketone compounds with a high synthetic potential. In this context, our project aimed at promoting this type of reaction under mild conditions without using a base. The strategy adopted was based on the use of α-trialkylsilyl-α-diazoacetones and their specific nucleophilic activation by a fluoride ion. Initially, the synthesis of α-trialkylsilyl-α-diazoacetone was optimized and then, an extensive study of the reaction parameters allowed the development of an efficient aldolisation of TES-diazoacetone induced by TBAF. The nucleophilic, weakly basic conditions employed tolerate a wide range of substrates and constitute a practical high-yielding experimental procedure. The asymmetric extension of this methodology was then studied by using a chiral ammonium fluoride derived from Cinchona alkaloid. The condition set up allowed to elaborate the first enantioenriched beta-hydroxy-alpha-diazoacetones (e.e = 35%) in high yields. Finally, this methodology was successfully extended to TIPS-diazoacetone. The robustness of the TIPS protective group makes it possible to envision a range of synthetic « methyl-side » transformations without desilylation of the azomethine position of the diazo-aldol. This study paves the way for future exploration of the reactivity of TIPS diazoaldols
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Ji, Jing. "Poly(vinylidene fluoride) membranes." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/43532.
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Poly(vinylidene fluoride) (PVDF) membranes have been intensively investigated and commercialised with broad applications in water purification and wastewater treatment for decades due to its outstanding properties. Currently, PVDF membranes are mainly produced by the phase inversion technique, which is predominant in both laboratory research and industrial manufacturing. Various modification methods based on the phase inversion technique have also been developed to improve the membrane performances, but these improvements are incremental and there have been no important breakthroughs during the past decade. This thesis first explores the preparation of reinforced PVDF flat sheet membranes by blending nanoclay followed by the phase inversion process. Although the membranes showed improved water permeation flux and enhanced abrasion resistance, further improvements are limited by the phase inversion technique itself. Consequently, a new concept of membrane manufacturing procedure has been proposed by combining unidirectional crystallisation of green solvent and polymer diffusion. The new method uses crystallites of a solvent dimethyl sulfoxide with controlled sizes as pore templates to create enormous nanosized flow passages. It follows a completely different pore formation mechanism and therefore overcomes the drawbacks of the phase inversion technique. The resultant PVDF membranes have an asymmetric structure composed of a highly porous separation layer and gradually opened micro-channels. Due to the unique structure, the prepared membranes showed excellent permeation performances and mechanical properties overwhelming commercial PVDF membranes prepared by the phase inversion technique. The filtration performance of the PVDF membranes can be further improved by modification of the membrane material, for example, by blending polyethylene glycol in the dope solution. The obtained membrane with pore size of 36 nm showed extraordinary high flux of 1711 L/m2h and could withstand 35 bar in the test. Moreover, the new manufacturing process is of much fewer influencing factors compared to the phase inversion approach and thus highly reliable and repeatable. In principle, it is also applicable to other common polymeric membrane materials such as polyethersulfone and cellulose acetate.
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Collet, Pascal. "Le fluorure de sodium." Paris 5, 1988. http://www.theses.fr/1988PA05P015.
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Haïkel, Youssef. "Fluorose dentaire au Maroc." Université Louis Pasteur (Strasbourg) (1971-2008), 1990. http://www.theses.fr/1990STR1OD01.
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Sördell, Annelie, and Therese Lundgren. "Fluorlack- effekt på kariesprogression." Thesis, Karlstads universitet, Institutionen för hälsovetenskaper, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-48336.
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Introduktion: Karies är en vanlig sjukdom som drabbar stor del av befolkningen. För att karies ska uppstå behövs tand, bakterier och frekvent intag av fermenterbara kolhydrater. En skyddande faktor mot karies är fluor vilket hämmar demineralisering samt gynnar remineralisering. Det har visats att fluorlack kan förebygga karies men även hämma kariesprogression på viss befintlig karies. Syfte: Att beskriva olika fluorlackers progressionshämmande effekt på karies. Frågeställning: Vilket fluorlack fungerar bäst i progressionshämmande syfte? Metod: En litteraturstudie Resultat: Resultatet visade progressionshämmande effekt av fluorlacker på emalj-, dentin- och rotkaries. Skillnaden mellan flera lackers effekt var på grund av olika lackningsintervall, utvärderingstid och liknande resultat svår att skilja åt. Konklusion: Alla fluorlacker, förutom Prevident (5 % NaF), involverade i denna studie sågs ha progressionshämmande effekt på karies. Detta tyder på att fluorlackning är bättre än ingen fluorlackning oavsett fluorlack. Duraphat (5 % NaF) sågs i vissa studier ha något bättre effekt än andra fluorlacker.
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Maesano, Tallone Élise. "Photooxydation d'hydrocarbures polyaromatiques a groupement methylene actif : fluorene, acenaphtene, cyclopenta(d,e,f)phenanthrene, benzo(a) fluorene et benzo(b) fluorene." Toulon, 1992. http://www.theses.fr/1992TOUL0006.
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Le sujet de cette these concerne l'etude de la photooxydation de cinq hydrocarbures polyaromatiques (hpa) a groupement methylene actif. Il s'agit du fluorene, de l'acenaphtene, du cyclopenta(d,e,f) phenanthrene et des benzo(a) et (b) fluorenes. Ces composes ont ete choisis parce qu'ils possedent une structure originale, et qu'ils sont egalement reconnus comme des polluants notoires dans l'environnement. L'interet de cette etude est double: un aspect purement photochimique et un aspect plus applique a la chimie de l'environnement. Dans l'etude photochimique, la reactivite de chaque hpa, a ete determinee sous l'action d'un rayonnement ultraviolet, en absence et en presence d'un photooxydant le peroxyde d'hydrogene. Nous avons tout d'abord caracterise, les differents photoproduits issus de ces irradiations et propose les mecanismes reactionnels rendant compte de leurs photodecompositions et de leurs mineralisations. Les cinetiques de decompositions, ainsi que les rendements quantiques a 254 et 313 nanometres, nous ont permis, en fonction des travaux de zepp et cline, d'estimer les temps de residence de ces hpa dans l'environnement
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Chu, Chun-hung, and 朱振雄. "Effectiveness of silver diamine fluoride and sodium fluoride varnish in arresting dentine caries." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B30162506.
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Hmida, Fadoua. "Spectroscopie FTIR à haute résolution de SO2F2." Thesis, Reims, 2017. http://www.theses.fr/2017REIMS042.
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Les travaux présentés dans ce manuscrit sont consacrés à l’étude de la spectroscopie FTIR à très haute résolution de la molécule de fluorure de sulfuryle SO2F2 qui est apparu récemment comme un polluant atmosphérique important. Une très bonne modélisation de son spectre d’absorption est donc essentielle pour les mesures de concentration atmosphérique.Ce manuscrit comporte cinq parties. La première partie de ce travail de thèse concerne les propriétés de la molécule du fluorure de sulfuryle. La deuxième partie décrit le modèle théorique (formalisme tensoriel, Hamiltonien et moment dipolaire effectifs) que nous avons utilisé pour effectuer les analyses. La troisième partie expose les conditions expérimentales des différents spectres que nous avons enregistré à la ligne AILES du synchrotron SOLEIL à Saint-Aubin (Paris). La quatrième partie décrit le logiciel C2vTDS et enfin dans la cinquième partie, nous présentons les résultats des différentes analyses.Cette thèse a été effectuée au sein du Groupe de Spectrométrie Moléculaire et Atmosphérique (GSMA) de l’Université de Reims Champagne-Ardenne et au Laboratoire Dynamique Moléculaire et Matériaux Photoniques (LDMMP) à l’Ecole Nationale Supérieure d’Ingénieurs de l’Université de TunisThe work presented in this manuscript is devoted to the study of very high resolution FTIR spectroscopy of the molecule of sulfuryl fluoride, SO2F2, which recently appeared as an important atmospheric pollutant. However, a very good modeling of its absorption spectrum is essential for atmospheric concentration measurements.This manuscript has five parts. The first part deals with the properties of the molecule of sulfuryl fluoride. The second part describes the theoretical model (tensor formalism and effective Hamiltonian and dipole moment) that we used to perform the analyzes. The third part presents the experimental conditions of the different spectra that we recorded at the AILES line of the SOLEIL synchrotron at Saint-Aubin (Paris). The fourth part describes the software C2vTDS and finally in the fifth part we present the results of the different analyzes.This thesis was performed in the Molecular and Atmospheric Spectrometry Group (GSMA) of the University of Reims Champagne-Ardenne and the Laboratory of Molecular Dynamics and Photonic Materials (LDMMP - ENSIT) of the University of Tunis
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Berger, Tobias. "Fluoride in surface water and groundwater in southeast Sweden : sources, controls and risk aspects." Doctoral thesis, Linnéuniversitetet, Institutionen för biologi och miljö (BOM), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-52562.
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The aim of this thesis is to determine the sources, controls and risk aspects of fluoride in surface water and groundwater in a region of southeastern Sweden where the fluorine-rich 1.45 Ga circular Götemar granite (5 km in diameter) crops out in the surrounding 1.8 Ga granites and quartz monzodiorites (TIB rocks). The materials of this thesis include both primary data, collected for the purpose of this thesis, and a large set of secondary data, retrieved from the Swedish Nuclear Fuel and Waste Management Co., the Swedish Geological Survey and the Kalmar County Council. A characteristic feature of the area is high fluoride concentrations in all kinds of natural waters, including surface waters (such as streams) and groundwater in both the Quaternary deposits (regolith groundwater) and bedrock fractures (fracture groundwater). A number of potential sources and controls of the high fluoride concentrations were investigated, including a variety of geological, mineralogical, mineral-chemical and hydrological features and processes. For the stream waters and regolith groundwater, high fluoride concentrations were correlated with the location of the Götemar granite. This finding is explained by the discharge of fluoride-rich groundwater from fractures in the bedrock and/or the release of fluoride due to the weathering of fluorine-bearing minerals in the Quaternary deposits; however, the Quaternary deposits had considerably lower fluoride concentrations than the underlying bedrock. The high fluoride concentrations in the fresh fracture groundwater (up to 7.4 mg/L) in the TIB-rocks are proposed to be the result of long residence times and the alteration/dissolution of fluorine-bearing primary and secondary minerals along the fracture walls. In terms of risk aspects, this thesis shows that fluoride can add to the transport and inorganic complexation of aluminium in humic-rich, acidic streams. Additionally, 24 % of the children in households with private wells in Kalmar County were assessed to be at risk of excess fluoride intake based on the WHO drinking water guideline value (1.5 mg/L). However, the risk increased significantly when instead the US EPA reference dose (0.06 mg/kg-day) was used, both when all relevant exposure pathways were taken into account as well as water consumption alone. Hence, it is shown that the risk of an excess intake of fluoride is strongly dependent on the basis for evaluation.
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Santos, Cristiane Brand?o. "Ingest?o de fluoreto e risco de fluorose dent?ria." Universidade Estadual de Feira de Santana, 2017. http://tede2.uefs.br:8080/handle/tede/tede/639.
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Santos, Cristiane Brand?o.pdf: 1618648 bytes, checksum: 207f755363fb3b9a7dca89df5c0b2fbc (MD5)Made available in DSpace on 2018-07-10T22:51:13Z (GMT). No. of bitstreams: 1 Santos, Cristiane Brand?o.pdf: 1618648 bytes, checksum: 207f755363fb3b9a7dca89df5c0b2fbc (MD5) Previous issue date: 2017-06-02
Funda??o de Amparo ? Pesquisa do Estado da Bahia - FAPEB
Introduction: Dental fluorosis is an alteration in dental enamel mineralization, related to fluoride (F?) intake. Objectives: To investigate the impact of F? addition in toothpaste on the prevalence of dental fluorosis and to compare methods for F? determination in samples of diet and toothpaste. Methods: Two studies were developed: 1) systematic review of the literature, with meta-analysis, performed by two reviewers independently searching the four electronic databases (MEDLINE / PubMed; MEDLINE / Ovid; Bireme and Web of Science). The quality of articles eligible for Strengthening the Reporting of Observational Studies in Epidemiology (STROBE), and by the classification modified by Irani (2013); 2) a laboratory study that determined the F? concentration in the diet and dentifrice samples using two extraction methods: HMDS facilitated microdiffusion and hydrolysis in 0.01M HCl at times 30, 60 and 120 min of incubation. For analysis of the data, the one-way ANOVA test was applied. Results: 1) In the systematic review, eleven articles were eligible, and, when STROBE was applied, the number of items included ranged from 14 and 19, with an average of 16.3 and a standard deviation of 4.03; in the analysis of the classification modified by Irani (2013), two articles were classified as high quality and the rest of intermediate quality; 2) the method of extraction using 0.01M HCl, in the time 30 min, resulted in similar values to that expected by inactivation of 50% of the dentifrice?s F?. And in time 120 min resulted in similar values to HMDS facilitated microdiffusion. Conclusion: The majority of eligible articles in the systematic review found an association between the age of fluoride toothpaste use and dental fluorosis, but the prevalent severity of fluorosis was very mild, ie it does not imply dental fluorosis as a public health problem. It's the method of F? extraction using 0.01M HCl, in the experimental study, was promising to be used in evaluation of F? in dietary intake and dentifrices.
Introdu??o: Fluorose dent?ria ? uma altera??o na mineraliza??o do esmalte dental relacionada ? ingest?o de fluoreto (F?). Objetivos: Investigar o impacto da adi??o de F? aos dentifr?cios na preval?ncia de fluorose dent?ria e comparar metodologias para a determina??o da concentra??o de F? em amostras de dieta e dentifr?cio. M?todos: Dois estudos foram desenvolvidos: 1) revis?o sistem?tica da literatura, realizada por dois revisores que buscaram, de forma independente, os estudos em quatro bases de dados eletr?nicas (MEDLINE/PubMed; MEDLINE/Ovid; Bireme e Web of Science). Avaliou-se a qualidade dos artigos eleg?veis pelo Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) e pela classifica??o modificada por Irani (2013); 2) experimento laboratorial que determinou a concentra??o de F- nas amostras de dieta e dentifr?cio utilizando-se dois m?todos de extra??o: microdifus?o facilitada por HMDS e hidr?lise em HCl 0,01M com tempos 30, 60 e 120 minutos de incuba??o. Para an?lise dos dados foi aplicada o teste ANOVA um crit?rio. Resultados: 1) Na revis?o sistem?tica, onze artigos foram eleg?veis, e quando aplicado o STROBE o n?mero de itens inclu?dos variou entre 14 e 19, com m?dia de 16,3 e desvio padr?o 4,03; na an?lise da classifica??o modificada por Irani (2013), dois artigos foram classificados como de alta qualidade e o restante de qualidade intermedi?ria. 2) A t?cnica de extra??o em HCl 0,01M no tempo 30 minutos resultou em valores semelhantes ao esperado pela inativa??o de 50% do F? do dentifr?cio. E o tempo de 120 minutos resultou em resultados semelhantes ? t?cnica de microdifus?o facilitada por HMDS. Conclus?o: A maoiria dos artigos eleg?veis da revis?o sistem?tica encontraram associa??o entre idade do uso do dentifr?cio fluoretado e fluorose dental, por?m a severidade prevalente da flurose foi o grau muito leve, ou seja, n?o implica considerar fluorose dental como um problema de sa?de p?blica. E o estudo laboratorial sugere que o m?todo de extra??o de F? em HCl 0,01M ? promissor para ser utilizado em trabalhos de avalia??o da ingest?o de F? pela dieta e dentifr?cios.