In dieser Studie wurde der alleinige und gemeinsame Einfluss von 1.6 bis 14.5 mol% Wasser, 1.1 bis 18.3 mol% Fluor (F) und 0.5 bis 1.4 mol% Chlor (Cl) auf die Struktur und Viskosität von peralkalinen und peraluminösen Na2O CaO Al2O3 SiO2 Gläsern und Schmelzen mit ~ 66 mol% SiO2 (auf volatilfreier Basis) untersucht. Die Zusammensetzung der peralkalinen Proben entspricht einem Modellsystem für Phonolithschmelzen. Die wasserfreien Proben wurden in 1 atm Öfen aus Oxid und Karbonatverbindungen sowie Halogeniden hergestellt. Die wasserhaltigen peralkalinen Proben wurden in einer innenbeheizten Gasdruckanlage und die wasserhaltigen peraluminösen Proben in einer Stempelzylinderpresse hergestellt. Die Viskosität der Proben wurde mit der Mikropenetrationstechnik (108.5 1013 Pa s) und der „parallel plate“ Methode (105.5 Pa s 109 Pa s) gemessen. Die Struktur der Gläser wurde mittels „magic angle spinning“ (MAS) Kernspinresonanzspektroskopie (NMR) anhand der Nuklide 19F, 23Na, 27Al, 29Si and 35Cl analysiert. Fluor und Wasser allein oder in Kombination verringern die Viskosität der Schmelzen, wobei der Effekt von Wasser stärker ist als der von F. Beide Volatile verringern die Viskosität von peraluminösen Schmelzen stärker als in den peralkalinen Schmelzen. Für die peralkalinen Schmelzen wurde eine Verringerung der Viskosität durch F bis zu einer Konzentration von 1.9 mol% F festgestellt, jedoch für eine Konzentration von 6.2 mol% F wurde keine weitere Verringerung der Viskosität festgestellt. In den peraluminösen Schmelzen hingegen wurde bis zu einer Konzentration von 18.3 mol% F ein stetiger Abfall der Viskosität mit zunehmendem Fluorgehalt beobachtet. Der gemeinsame Einfluss von F und Wasser ist auf Grund ihrer jeweiligen Einzeleffekte geringer als angenommen, was zeigt, dass die Effekte von F und Wasser auf die Viskosität nicht unabhängig voneinander sind. Der zusammensetzungs und konzentrationsabhängige Effekt von F auf die Viskosität der Schmelzen stimmt mit Unterschieden im Einbaumechanismus von F überein. 19F MAS NMR Spektren zeigen, dass in den peralkalinen Gläsern F sowohl in „salzartigen“ F Ca(n) und F Na(n) als auch in nicht brückenbildenden Si F Na(n), Al F Ca(n), Al F Na(n) und brückenbildenden Al F Al Umgebungen vorkommt („n“ bedeutet, dass die Anzahl der Atome unklar oder variabel ist). F Ca(n) ist die am häufigsten vorkommende Umgebung, obwohl Ca das am wenigsten häufige Kation in den Proben ist. In den peraluminösen Gläsern existiert F nur in Si F und Al F Umgebungen, wobei Al F Na(n) die am häufigsten vorkommende Umgebung ist. Die Bildung von salzartigen F Ca(n) und F Na(n) Umgebungen sollte zu einem Anstieg der Viskosität durch eine Verringerung der netzwerkmodifizierenden Kationen führen. Die Bildung von Si F und Al F Umgebungen sollte die Viskosität entweder auf Grund einer Reduzierung von brückenbildenden Sauerstoffen durch nicht brückenbildende F oder durch einen Austausch von brückenbildenden Sauerstoffen durch brückenbildende F, welche eine niedrigere Bindungsstärke haben, verringern. Daraus lässt sich schließen, dass F die Viskosität in peralkalinen Schmelzen weniger stark verringert als in peraluminösen Schmelzen, weil F in den peralkalinen Schmelzen in Umgebungen existiert, welche die Viskosität erhöhen oder erniedrigen können, während F in den peraluminösen Schmelzen nur in Umgebungen existiert, welche die Viskosität verringern. Der konzentrationsabhängige Einfluss von F auf die Viskosität in den peralkalinen Schmelzen scheint in Zusammenhang mit einer Änderung in der Fluorspeziation zu stehen: Der relative Anteil von F Ca(n) Umgebungen, von denen anzunehmen ist, dass sie die Viskosität erhöhen, steigt von 42 auf 53% bei einem Anstieg im F Gehalt von 1.2 auf 6.2 mol% F. Veränderungen in der Fluorspeziation scheinen ebenfalls verantwortlich dafür zu sein, dass der Effekt von F und Wasser in Kombination geringer ist als erwartet. 19F MAS NMR Spektren von fluor und wasserhaltigen Proben zeigen, dass der relative Anteil von Al F Umgebungen, von denen anzunehmen ist, dass sie die Viskosität verringern, mit zunehmendem Wassergehalt abnimmt und dass im Gegenzug der relative Anteil von F Ca(n) Umgebungen zunimmt. Mit IR Spektroskopie wurde in den peralkalinen Proben kein Unterschied im OH/H2O Verhältnis bei gleichem Gesamtwassergehalt durch die Präsenz von F beobachtet. Im Gegensatz dazu gibt es starke Hinweise darauf, dass F in den peraluminösen Proben das OH/H2O Verhältnis bei gleichem Gesamtwassergehalt verringert, was erklären würde, weshalb F und Wasser in Kombination die Viskosität weniger verringern als von ihren Einzeleffekten zu erwarten wäre. Der Einfluss von Cl auf die Viskosität und Struktur der Schmelzen und Gläser ist sehr unterschiedlich verglichen mit F. Cl erhöht die Viskosität in den peralkalinen Schmelzen und verringert die Viskosität in den peraluminösen Schmelzen. Viskositätsmessungen von wasserhaltigen, chlorfreien und chlorhaltigen peralkalinen Schmelzen zeigen, dass der Effekt von Cl auf die Viskosität nicht durch die Präsenz von Wasser beeinflusst wird. Das beobachtete 35Cl NMR Signal zeigt, dass sowohl in den peralkalinen als auch in den peraluminösen Gläsern Cl in Na Ca Cl Umgebungen mit einem hohen Na Anteil existiert, was auf Grund des Ca/Na Verhältnisses von 1/5 zu erwarten war. Die Cl Umgebung in den peralkalinen und peraluminösen Gläsern ist ähnlich, jedoch beinhaltet die Cl Umgebung in den peraluminösen Gläsern mehr Ca. In den 35Cl MAS NMR Spektren wurde im Vergleich zu einem Natriumsilikatglas nur ein Teil des 35Cl NMR Signals der peralkalinen und der peraluminösen Proben beobachtet. Das fehlende Signal deutet darauf hin, dass ein Teil der Cl Atome in verzerrten oder ungeordneten Umgebungen existiert, welche eine Signalbreite haben, die zu groß ist, um mit den verwendeten NMR Spektroskopie Methoden gemessen werden zu können. Der Anstieg der Viskosität durch Cl in den peralkalinen Schmelzen kann dadurch erklärt werden, dass Cl die Anzahl der netzwerkmodifizierenden Kationen reduziert, während mehrere Möglichkeiten zur Diskussion stehen, weshalb Cl die Viskosität in peraluminösen Schmelzen verringert. Die Effekte von F und Cl auf die Viskosität sind unabhängig voneinander und summieren sich auf. Es wurde mit NMR Spektroskopie kein Hinweis dafür gefunden, dass F einen Einfluss auf den Einbaumechanismus von Cl hat.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 5 uppsatser.

Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (leaves 87-97).

Thesis (Ph.D.)--McMaster University, 2004. / Advisor: G. J. Schrobilgen. Includes bibliographical references (leaves 333-352). Also available online.

A doença cárie pode ser tratada com tratamento preventivo e ou tratamento restaurador. Para o tratamento preventivo, pode-se lançar mão da utilização do flúor, sendo sua utilização bastante difundida na Odontologia como eficaz método de promoção de saúde bucal. Já para o tratamento restaurador, utilizam-se materiais restauradores, sendo os compósitos odontológicos umas das principais escolhas entre os materiais restauradores estéticos usados na Odontologia. O objetivo deste estudo foi avaliar a ação de soluções fluoretadas na estabilidade de cor, rugosidade de superfície e análise qualitativa por microscopia eletrônica por varredura de compósitos odontológicos. Após confecção e polimento, os corpos de prova foram imersos em água destilada (controle), flúor fosfato acidulado (1,23%), gel fluoretado neutro (2%) e solução de flúor para bochechos diário (0,05%) por períodos de simulação correspondentes a 1 a 5 anos de uso clínico da solução fluoretada. Foram realizadas leituras de cor (&Delta;E), rugosidade de superfície (Ra) e microscopia eletrônica de varredura previamente e posteriormente a cada ano de ciclagem com as soluções fluoretadas estudadas. Após análise estatística (3-way ANOVA com medidas repetidas Bonferroni nível de significância em p<0.05), observou-se que todos os compósitos estudados apresentaram discreta alteração de cor, dentro do limite clinicamente aceitável (&Delta;E<3,3), sendo crescente de acordo com os anos de simulação clínica de 1 até 5 anos. Quanto à rugosidade, observou-se um padrão de comportamento não homogêneo, sendo, após 5 anos de simulação de uso clínico das soluções fluoretadas, menor que a rugosidade de superfície necessária para causar um aumento da retenção de biofilme dentário (Ra>0,2 &mu;m) para todos os compósitos analisados. A análise das fotomicrografias demonstrou o aparecimento de pequenas depressões na superfície das amostras e penetração de água (solvente) no interior dos compósitos diretos. Conclui-se que a alteração de cor dos compósitos foi clinicamente aceitável e a alteração de rugosidade de superfície não é clinicamente significante após imersão em todas as soluções fluoretadas e tempos estudados. / Dental caries can be treated with preventive treatment or restorative treatment. For preventive treatment, we can resort to the use of fluoride, and its widespread use in Dentistry as an effective method of promoting oral health. As for the restorative treatment, are used restorative materials, dental composites are one of the first choices among the materials used in aesthetic restorative dentistry. The aim of this study was to evaluate the effect of fluoride solution in color stability, surface roughness and qualitative analysis by scanning electron microscopy of dental composites. After preparation and polishing, the specimens were immersed in distilled water (control), acidulated phosphate fluoride (1.23%), neutral sodium fluoride gel (2%) and fluoride mouthwashes for daily (0.05%) for periods simulation corresponding to 1 to 5 years of clinical use of fluoride solution. Readings were taken in color (&Delta;E), surface roughness (Ra) and scanning electron microscopy before and after each year of cycling with the fluoride solution studied. After statistical analysis (3-way repeated measures ANOVA - Bonferroni - a significance level of p<0.05), was observed that all the composites studied showed a slight color change, within clinically acceptable (&Delta;E<3.3), being increased according to the years of clinical simulation from 1 to 5 years. As for the roughness, there was a pattern of behavior is not homogeneous, and, after five years of simulated clinical use of fluoride solution, smaller than the surface roughness required to cause an increased retention of dental plaque (Ra>0.2 &mu;m) for all composites analyzed. The analysis of the photomicrographs showed the appearance of small depressions on the surface and penetration of water (solvent) within the direct composites. We conclude that the color change of the composites was clinically acceptable and the surface roughness change is not clinically significant after immersion in all fluoride solution and times studied.

Made available in DSpace on 2014-10-09T12:35:12Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:56:12Z (GMT). No. of bitstreams: 0 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP / FAPESP:11/03138-8

In this thesis new synthetic routes towards perfluorinated compounds are described, as well as their radiolabelling with fluorine-18, with the aim of application in pharmaceutically interesting targets. Part A investigates late-stage fluorination, i.e. retrosynthetic C–F bond disconnections. A silver catalysed electrophilic fluorodecarboxylation of fluorinated carboxylic acids for the formation of difluoromethyl-, trifluoromethyl-, and pentafluoroethylarenes is developed and transferred to a radiochemistry setting using [¹⁸F]Selectfluor bis(triflate). Part B explores late-stage perfluoroalkylation via cross-coupling strategies. The use of visible light-mediated ruthenium catalysis is investigated for the radical trifluoromethylation and pentafluoroethylation of vinyl- and alkynylsilanes and alkynes. Finally, the first generally applicable copper-mediated cross-coupling of Ruppert-Prakash-like aryl(tetrafluoroethyl)trimethylsilanes (ArCF2CF2SiMe3) is presented.

Os pegmatitos estudados estão associados à fácies albita granito do granito Madeira, a qual corresponde ao depósito de Sn-Nb-Ta (F, ETR, U, Th) Madeira, na mina Pitinga (AM) e estão associados a falhas de orientação N320/60SW. Estas rochas contêm minerais poucos comuns como gagarinita (NaCaYF6), genthelvita (Zn4Be3(SiO4)3S) e polilitionita (KLi2AlSi4O10(F, OH)2), além de grandes quantidades de criolita (Na3AlF6). Com base na composição química e mineralógica, estes pegmatitos foram classificados em três tipos: PEG ANF (teores médios de K e Na, com alta concentração de anfibólios), PEG POL (rico em K e com alta concentração de polilitionita) e PEG CRIO (rico em Na e com alta concentração de criolita). Estes pegmatitos contêm altos teores de ETR (especialmente ETRP) e Y, que estão concentrados principalmente na xenotima e na gagarinita. Estes elementos também ocorrem em elevados teores na grande parte dos demais minerais analisados. Também se destacam as concentrações anômalas de F, muito superiores às detectadas nos pegmatitos de outras localidades, e que promoveram o enriquecimento em Li, Na, K, Rb e Cs. A similaridade na composição química do AGN com os pegmatitos indica que eles possuem a mesma fonte. / The pegmatites studied are associated with the albite granite facies of the Madeira granite, which corresponds to the Sn-Nb-Ta (F, ETR, U, Th) Madeira deposit at the Pitinga mine (AM). They are associated with N320/60SW orientation faults. These rocks contain few common minerals such as gagarinite (NaCaYF6), genthelvite (Zn4Be3(SiO4)3S) and polylithionite (KLi2AlSi4O10(F,OH)2), as well as large amounts of cryolite (Na3AlF6). Based on the chemical and mineralogical composition, these pegmatites were classified into three groups: PEG ANF (medium K and Na, with high concentration of amphiboles), PEG POL (K rich and with high polylithionite concentration) and PEG CRIO (rich in Na and with high concentration of cryolite). These pegmatites contain high levels of REE (especially HREE) and Y, which are mainly concentrated in xenotime and gagarinite. These elements also occur at high levels in most of the other minerals analyzed. Anomalous concentrations of F, much higher than those detected in pegmatites from other localities, were also highlighted, and promoted enrichment in Li, Na, K, Rb and Cs. The similarity in the chemical composition of AGN with pegmatites indicates that they have the same source.

Made available in DSpace on 2014-06-11T19:33:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-08-14Bitstream added on 2014-06-13T20:44:31Z : No. of bitstreams: 1 santos_nb_dr_araca.pdf: 486492 bytes, checksum: ee801e0b89ebab07fe599f4eaad17a0f (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / 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)

Made available in DSpace on 2014-06-11T19:33:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-06-26Bitstream added on 2014-06-13T19:03:52Z : No. of bitstreams: 1 000736961.pdf: 1111199 bytes, checksum: 66817919e317b4e4627df34fe48a7d25 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Nos últimos anos, tem havido uma redução acentuada nos índices de cárie dentária em diversas regiões do mundo, fato que tem sido atribuído ao uso de produtos fluoretados, como o dentifrício. Simultaneamente, nota-se a ocorrência do aumento da prevalência de fluorose dentária. O NaF ocasiona inibição da glicólise, diminuição da secreção de insulina e hiperglicemia. Muitas destas respostas sugerem que o NaF pode ocasionar resistência à insulina. Sabendo-se que o fluoreto pode alterar o metabolismo de carboidratos, tornou-se fundamental caracterizar o efeito do NaF sobre: 1) o grau de fosforilação em serina do IRS-1, em tecidos responsivos à insulina; 2) concentração plasmática de colesterol, triglicérides e TNF-α. Para tanto, foram utilizados ratos Wistar (1 mês de idade) castrados. Após 30 dias da castração, os animais foram divididos aleatoriamente em dois grupos: 1) grupo controle (CN), o qual foi submetido ao tratamento sem NaF, mas com uma solução de NaCl (9,54 mg/kg p.c.) que contém a mesma quantidade de sódio em relação à do grupo fluoreto de sódio; 2) grupo NaF (FN) que foi submetido ao tratamento com NaF (4,0 mg de flúor/kg p.c.) na água de beber e na ração durante 42 dias. Após 6 semanas, foi realizada a avaliação da concentração plasmática de TNF-α e a quantificação do grau de fosforilação em serina de IRS-1, após estímulo insulínico, em tecido muscular gastrocnêmio (G), tecido hepático (TH) e em tecido adiposo branco periepididimal (TAB). Também foi realizada a avaliação da concentração plasmática de colesterol e triglicérides. O tratamento crônico com NaF promoveu: 1) aumento significativo, após estímulo insulínico, no grau de fosforilação em serina do substrato do receptor de insulina (IRS-1) no tecido adiposo branco; 2) nenhuma alteração, após estímulo... / Over the last years, there has been a significant reduction in the incidence of dental caries in several regions of the world. This has been attributed to the use of fluoridated products, such as toothpaste. Simultaneously, there has been an increase in the prevalence of dental fluorosis. NaF causes glycolysis inhibition, decrease on insulin secretion and hyperglycemia. These responses suggest that NaF can cause insulin resistance. Knowing that F can interfere with carbohydrate metabolism, we felt it was important and fundamental to undertake a study to examine the chronic effect of NaF on: 1) IRS-1 serine phosphorylation in insulin responsive tissues; 2) plasmatic concentration of cholesterol, triglycerides and TNF alpha. For this study, castrated Wistar male rats (1 month of age) were used. Thirty days after castration, the animals were randomly divided in two groups: 1) control group (CN) which was subjected to treatment without NaF, but with a solution of NaCl (9.54 mg / kg bw) which contains the same amount of sodium in relation to the group NaF; 2) group NaF (FN) that was submitted to treatment with NaF administered in the drinking water and F contained in food pellets (F total inferred: 4.0 mg F / Kg bw / day in the form of NaF) during 42 days. After 6 weeks, the evaluation of plasmatic concentration of TNF-α and quantification of IRS-1 serine phosphorylation status after insulin stimulus in muscle, liver and white adipose tissue were performed. The plasmatic concentration of cholesterol and triglycerides also were evaluated. The chronic treatment with NaF promoted: 1) increase in the IRS-1 serine phosphorylation status after insulin stimulus in the white adipose tissue; 2) no alteration in the IRS-1 serine phosphorylation status after insulin stimulus in the liver and muscle; 3) increase in the plasmatic concentration of TNF-α, triglycerides, total cholesterol and ...