Submitted by Tatiana Silva (tsilva@icict.fiocruz.br) on 2012-12-26T16:35:34Z No. of bitstreams: 1 giselle_v_f_brunoro_ioc_bcm_0003_2010.pdf: 21708458 bytes, checksum: 70db8700af3ee0df74e2440ef79ab8fc (MD5) / Made available in DSpace on 2012-12-26T16:35:34Z (GMT). No. of bitstreams: 1 giselle_v_f_brunoro_ioc_bcm_0003_2010.pdf: 21708458 bytes, checksum: 70db8700af3ee0df74e2440ef79ab8fc (MD5) Previous issue date: 2010 / Fundação Oswaldo Cruz.Instituto Oswaldo Cruz. Rio de janeiro, RJ, Brasil / O câncer de mama é a principal causa de morte por câncer em mulheres no mundo. De acordo com o Instituto Nacional do Câncer, 7.470 novos casos são estimados em 2010 apenas no Rio de Janeiro. A maioria dos casos de câncer de mama são originados nas células ductais mamárias. Elas secretam o fluido aspirado de mama (NAF), que contém proteínas intimamente associadas ao microambiente tumoral. O objetivo deste trabalho foi utilizar a abordagem proteômica como ferramenta para caracterizar e comparar o NAF das duas mamas de pacientes brasileiras com câncer da mama unilateral. A concentração média de proteínas das amostras controle, tumor benigno ou câncer de mama de 13 mulheres foi aproximadamente 115 ± 60 μg/μL. A atividade proteolítica do NAF foi visualizada por zimografia das amostras de duas pacientes. Observamos que o padrão de bandas gelatinolíticas diferiu substancialmente entre as pacientes, mas não entre as duas mamas do mesmo indivíduo. As enzimas proteolíticas se apresentaram sensíveis à inibição por agentes quelantes de metais (EDTA e orto-fenantrolina). As amostras de NAF também foram submetidas à 2D-PAGE em condições otimizadas (IPG 4-7 e aplicação de amostra por reidratação in gel) e poucos spotsproteicos muito abundantes foram detectados e identificados por espectrometria de massas MALDI-TOF/TOF como albumina, imunoglobulinas, zinco-α2-glicoproteína e proteína induzida por prolactina. Para enriquecer o NAF em suas proteínas menos abundantes, testamos estratégias de depleção usando a coluna de múltipla afinidade Hu-6 da Agilent ou proteína L agarose. Este passo de pré-fracionamento introduziu variabilidade adicional importante nas amostras e por este motivo não foi empregado em etapas posteriores do estudo. Catorze amostras de NAF das mamas pareadas de mulheres com câncer unilateral foram sistematicamente comparadas por 2D-DIGE. Foram observadas diferenças qualitativas substanciais entre as pacientes, prejudicando as comparações quantitativas entre as amostras. Dois grandes perfis proteicos distintos foram definidos por 2D-DIGE. O perfil A caracterizou-se pela presença de dois grupos de spotsácidos típicos (pI ≈ 4,5 e MM 29,5 e 18 kDa), ausentes no perfil B. A presença de glico- e fosfo-proteínas foi determinada em amostras de ambos os perfis após revelação dos géis 2D com ProQ- Emerald ou Diamond,respectivamente. As amostras dos dois perfis se mostraram muito mais ricas em glicoproteínas do que em fosfoproteínas. Este trabalho constituiu a primeira caracterização proteômica sistemática do NAF de pacientes brasileiras com câncer de mama unilateral. Nossos resultados mostraram uma variabilidade importante do conteúdo de proteínas nas amostras individuais de NAF, sugerindo a necessidade de uma estratificação mais uniforme daspacientes. Por fim, o emprego de tecnologias proteômicas mais sensíveis e acuradas deverá ser necessário para possibilitar a detecção e identificação de proteínas menos abundantes no NAF, que poderão constituir candidatos a biomarcadores do câncer de mama. / Breast cancer is the main cause of cancer deaths worldwide in women. According to the Instituto Nacional do Câncer, 7.470 new cases are estimated for 2010 in Rio de Janeiro. Most breast cancer cases originate from mammary ductal cells that secrete the nipple aspirate fluid (NAF), witch contains proteins associated with the breast cancer microenvironment. The aim of this study was to use the proteomic approach as a reliable tool to characterize NAF samples from brazilian patients with unilateralbreast cancer. The mean concentration of NAF proteins from healthy, benign or cancer breast samples from 13 women was approximately 115 ±60 μg/μL. The proteolytic activity of NAF samples from both breasts of two patients was visualized by SDS-PAGE zymography.The patterns of gelatinolytic bands differed substantially between patients but were very similar within the same patient. The proteolytic activity was sensible to inhibition by metal quelators (EDTA and orthophenantrolin). In this study, NAF samples weresubmitted to 2D-PAGE under optimized conditions (IPG 4-7 and sample in gel rehydratation) and a few very abundant protein spots were detected. They were identified by MALDI-TOF/TOF MS as albumin, immunoglobulins, zinc-α2-glycoprotein and prolactin-induced protein.To enrich NAF for less abundant proteins, we tested protein depletion using AgilentHu-6 column or Protein L Agarose. These pre-fractionation steps introduced important additional variability in the samples and were not further used. Fourteen NAF samples from tumorous and non-tumorous breasts of women with unilateral cancer were systematically compared by 2D-DIGE. Substantial qualitative individual differences were observed, impairing proper quantitative comparisons. Two main 2D-DIGE protein profiles were observed: profile A was characterized by two groups of acidic spots (pI ≈ 4,5 and MM 29,5 and 18kDa), not detected in profile B. The presence of glyco- and phosphoproteins was determined after staining NAF 2D gels with ProQ-Emerald or Diamond, respectively. The samples from both profiles were much richer in glycoproteins than phosphoproteins. This work was the first systematic proteomic characterization of NAF from brazilian patients with unilateral breast cancer. The results highlight important variability in the protein content of NAF samples, suggesting that a more uniform patient stratification and the use of more sensible and accurate proteomic technologies will be needed for the detection and identification of breast cancer biomarker candidates.

The thesis investigates the solubility of various sodium salts present in the waste tanks at the Hanford nuclear site. The experiments were conducted in different concentrations of caustic and in water at 25°C and 50°C. The results obtained from these studies will be used to improve existing databases for the Environmental Simulation Program (ESP, available from OLI Systems, Inc.), thereby increasing its accuracy in predicting waste behavior under high ionic strength conditions. Experiments were performed on the following systems: 1) NaF - NaNO3 - NaOH, 2) Na3PO4 - NaNO3 - NaOH, 3) NaF - Na3PO4 - 1m NaNO3 - NaOH, and 4) NaF - Na3PO4 - 3m NaNO3 - NaOH. The results obtained from these experiments were then compared to the ESP predictions and the available literature data. Comparision of the experimental work with the available literature data revealed that the data obtained from this study is in agreement with previous studies for the NaF - NaOH, NaNO3 - NaOH, and Na3PO4 - NaOH systems. This is the first report on solubilities for the Na - F - PO4 - OH system with added nitrate. The presence of sodium hydroxide was found to lower the solubility of natrophosphate, Na7F(PO4)2.19H2O. The solubility of this double salt was also significantly lowered in the presence of sodium nitrate. Error analysis of the experimental data was performed and indicated that the experimental molalities were accurate to within an average of + 0.02.

In introduction this graduation theses discource about phase diagrams and thein fission. Next part is about concrete phase diagrams NaF – KF, NaF – LiF, KF – LiF. Their determination trough use of cooling surves and their specification trough use of numerical method. Conclusion contains proposal of method for concrete phase diagram of NaF – KF – LiF.

I Sverige idag är förbränning av avfall med energiåtervinning den primära lösningen för avfall som inte återanvänds eller återvinns. Avfall innehåller en stor variation av material, och med det följer en del drifttekniska problem som kan uppstå i en panna, vilket begränsar pannans effektivitet. Olika grundämnen återfinns i olika avfallsfraktioner och somliga kan orsaka svåra problem med korrosion och beläggningsbildning i värmeöverförande delar nedströms förbränningszonen i en panna. Kraftvärmeindustrin har länge varit medvetna om riskerna till följd av klorrikt bränsle, då klor är ett ämne man vet bidrar till korrosion. Nya material gör dock att höga halter av, för kraftvärmeindustrin, tidigare okända grundämnen kommer in i anläggningarna. Ett av dessa grundämnen är fluor som förekommer bland annat i fluorpolymerer som är kemiskt inerta och hållbara plaster. Fluorpolymerer återfinns i exempelvis sport- och friluftskläder samt köksredskap och produktionen av dessa material bedöms öka kraftigt de närmaste åren.   Syftet med det här arbetet var att genom termodynamiska beräkningar och med förbränningsförsök i bänkskala undersöka fraktionering och sulfatering av fluor under ett antal olika förutsättningar. Fyra bränsleblandningar undersöktes vid förbränning i en 20 kW undermatad pelletsbrännare med rena träpellets dopade med natriumsalt. En blandning innehöll enbart natriumfluorid (NaF), en blandning innehöll enbart natriumklorid (NaCl), en blandning innehöll både NaF och NaCl samt en blandning innehöll NaF, NaCl och svavel. Under förbränningsförsöken noterades halterna av HCl, HF och SO2 i rökgaserna. Efterföljande analys av bottenaska, beläggningar och partiklar i rökgasen genomfördes med SEM/EDS samt XRD-analys. Resultatet visade att fluor verkar ha större benägenhet än klor att stanna i bottenaska, detta bekräftades både genom termodynamiska beräkningar och genom förbränningsförsök. Vidare visade termodynamiska beräkningar att en stor del av det fluor som tillsätts bör hamna i rökgasen som HF. Förbränningsförsöken visade att tillsats av svavel är ett effektivt sätt att minska andelen fluor i beläggningar samt partiklar i rökgasen och att sulfatering av fluorsalter sker vid lägre halter av svavel jämfört med klorsalter. I praktiken innebär detta att om halterna av fluorrikt bränsle ökar i en avfallsförbränningsanläggning bör andelen HF i rökgaserna öka samt att en del av det svavel som återfinns i bränsleblandningen och/eller tillsätts genom additiv kommer i första hand gå åt till sulfatering av fluorsalter om sådana bildas. Om distributionen är likartad om organiskt bundet fluor tillsätts, till exempel genom fluorplast, är inte undersökt i det här arbetet och är något som bör utredas framöver. / Combustion of waste in combined heat- and power plants are the primary solution for waste that is not recycled or reused in Sweden today. Municipal solid waste contains a wide range of ash-forming elements, which could lead to operational problems in the boiler that limits the plant’s efficiency. Different elements are found in different waste fractions, and some can cause severe corrosion problems in heat transferring parts of the boiler. The heat and power industry has been aware of the problems associated with chlorine for a long time, as this is an element that is known to contribute to corrosion. New materials mean that high levels of previously unknown elements for the heat and power industry enters the plants. One of these elements is fluorine which is found in fluoropolymers which are chemically inert plastics. Fluoropolymers are found in sports and outdoor clothing, as well as cookware and a number of other products, and the production of these type of materials is expected to increase significantly over the next few years.   The purpose of this work was to investigate the distribution of fluorine by addition of sodium fluoride (NaF) to pure wood pellets. This was done through thermodynamic calculations and bench scale combustion tests. Four fuel mixtures were tested, one containing NaF alone, one containing sodium chloride (NaCl), one containing both NaF and NaCl and one containing NaF, NaCl and sulfur. During combustion tests, the concentrations of HCl, HF and SO2 in the flue gases were logged. Analysis of bottom ash, deposits and particles in the flue gas was performed with SEM/EDS and XRD-analysis after each combustion test. The results showed that fluorine appears to be more likely than chlorine to stay in the bottom ash. This was confirmed by thermodynamic equilibrium calculations and by combustion tests. Furthermore, the thermodynamic equilibrium calculations showed that a large share of fluorine should end up in the flue gas as HF. Furthermore, the combustion tests showed that sulfation of fluorine salts occurs at lower levels of sulfur than sulfation of chlorine salts. In practice, this means that if the levels of fluorine-rich fuel increases in a waste incineration plant, the proportion of HF in the flue gases should increase and that some of the sulfur in the fuel mixture will be used for sulfation of fluorine salts if they are formed. The distribution of fluorine if fluorinated plastics are added to the fuel is not investigated in this work and something that should be investigated in the future.

Yes / Purpose: Nipple secretions are protein-rich and a potential source of breast cancer biomarkers for breast cancer screening. Previous studies of specific proteins have shown limited correlation with clinicopatholigical features. Our aim, in this pilot study, was to investigate the intra- and inter-patient protein composition of nipple secretions and the implications for their use as liquid biopsies. Experimental design: Matched pairs of NAF (n=15) were characterised for physicochemical properties and SDS PAGE. Four pairs were selected for semi-quantitative proteomic profiling and trypsin-digested peptides analysed using 2D LC Orbitrap Fusion mass spectrometry. The resulting data was subject to bioinformatics analysis and statistical evaluation for functional significance. Results: A total of 1990 unique proteins were identified many of which are established cancer associated markers. Matched pairs shared the greatest similarity (average Pearson correlation coefficient of 0.94), but significant variations between individuals was observed. Conclusions: This was the most complete proteomic study of NAF to date providing a valuable source for biomarker discovery. The high level of milk proteins in healthy volunteer samples compared to the cancer patients was associated with galactorrhoea. Using matched pairs increased confidence in patient-specific protein levels but changes relating to cancer stage require investigation of a larger cohort. / Proteomics research was supported by Yorkshire Cancer Research projects, BPP047 and B381PA.

Yes / There has been tremendous progress in detection of breast cancer in postmenopausal women, resulting in two-thirds of women surviving more than 20 years after treatment. However, breast cancer remains the leading cause of cancerrelated deaths in premenopausal women. Breast cancer is increasing in younger women due to changes in life-style as well as those at high risk as carriers of mutations in high-penetrance genes. Premenopausal women with breast cancer are more likely to be diagnosed with aggressive tumours and therefore have a lower survival rate. Mammography plays an important role in detecting breast cancer in postmenopausal women, but is considerably less sensitive in younger women. Imaging techniques, such as contrast-enhanced MRI improve sensitivity, but as with all imaging approaches, cannot differentiate between benign and malignant growths. Hence, current well-established detection methods are falling short of providing adequate safety, convenience, sensitivity and specificity for premenopausal women on a global level, necessitating the exploration of new methods. In order to detect and prevent the disease in high risk women as early as possible, methods that require more frequent monitoring need to be developed. The emergence of “omics” strategies over the last 20 years, enabling the characterisation and understanding of breast cancer at the molecular level, are providing the potential for long term, longitudinal monitoring of the disease. Tissue and serum biomarkers for breast cancer stratification, diagnosis and predictive outcome have emerged, but have not successfully translated into clinical screening for early detection of the disease. The use of breast-specific liquid biopsies, such as nipple aspirate fluid (NAF), a natural secretion produced by breast epithelial cells, can be collected non-invasively for biomarker profiling. As we move towards an age of active surveillance, home-based liquid biopsy collection kits are increasingly being applied and these could provide a paradigm shift where NAF biomarker profiling is used for routine breast health monitoring. The current status of established and newly emerging imaging techniques for early detection of breast cancer and the potential for alternative biomarker screening of liquid biopsies, particularly those applied to high-risk, premenopausal women, will be reviewed. / Proteomics research was supported by Yorkshire Cancer Research projects, BPP047 and B381PA, and co-funded by the European Regional Development Fund and the Republic of Cyprus through the Research Promotion Foundation projects ΥΓΕΙΑ/ΒΙΟΣ/0311(ΒΙΕ/07) and NEKYP/0311/17.

Apesar de diversos estudos demonstrarem resultados promissores da utilização da solução de AmF/NaF/SnCl2 na inibição da progressão da lesão de erosão dental, medidas que visam melhorar ainda mais sua eficácia são fundamentais. Sendo assim, este estudo in vitro e in situ se propôs a avaliar se o efeito protetor dessa solução pode ser potencializado pelo aumento da frequência de uso. Para tanto, foram obtidas, a partir de terceiros molares humanos hígidos, sessenta amostras de esmalte dental humano para o estudo in vitro (4 X 4 X 1 mm), e noventa e seis para o in situ (3 X 3 X 1 mm). Após a formação de lesão erosiva incipiente nas amostras in vitro, (ácido cítrico a 1%, pH 4,0, durante 3 minutos), estas foram divididas nos 5 grupos de tratamentos (n=12): G1 - água destilada (controle negativo); G2 - solução de NaF (controle positivo) 1x/dia; G3 - solução de NaF (controle positivo) 2x/dia; G4 - solução de AmF/NaF/SnCl2 1x/dia; G5 - solução de AmF/NaF/SnCl2 2x/dia. As amostras foram então submetidas a 5 dias de ciclagem erosiva através de 6 imersões diárias de 2 minutos em solução de ácido cítrico (0,05M, pH 2.6). Ao final da ciclagem erosiva, foi realizada a determinação do desgaste de superfície por meio de Perfilometria óptica. Para realização do desafio erosivo in situ, as amostras também foram submetidas à formação da lesão incipiente, com a mesma metodologia do in vitro. Doze voluntários participaram do estudo in situ e cruzado, dividido em quatro fases de 5 dias cada, os quais utilizaram um dispositivo removível inferior unilateral contendo 2 amostras de esmalte dental humano erodido, que foram trocadas a cada fase. As amostras foram divididas em 4 grupos de tratamentos (n=12), os mesmos utilizados na etapa in vitro, com exceção do grupo da solução de NaF 2x/dia. Durante a fase experimental in situ o dispositivo contendo as amostras foi submetido à ciclagem erosiva (ex vivo) semelhante à etapa in vitro. Ao final de cada fase experimental in situ, as amostras foram removidas do dispositivo e analisadas através de perfilometria, e foram consideradas as médias das amostras em duplicata para a análise estatística. A ANOVA mostrou que o desgaste superficial foi afetado pelos tratamentos avaliados tanto in vitro quanto in situ (p?0,001), com nível de significância de 5%. No estudo in vitro, o teste de Tukey demonstrou que não houve diferença entre os grupos de aplicação do NaF 1 (16,21 ±1,56) ou 2 vezes (15,39 ±1,01), que apresentaram redução limitada no desgaste quando comparado ao grupo da água destilada (20,36 ±1,56); já entre os grupos da solução AmF/NaF/SnCl2 houve diferença entre aplicação 1 (10,40 ±2,36) e 2 vezes (7,27 ±3,29), e que apesar de ambos demonstrarem redução significativa da perda de substrato, o aumento da frequência aumentou este potencial anti-erosivo. Na parte in situ, a solução de NaF não demonstrou capacidade de reduzir o desgaste, e apesar de não ter havido diferença significante entre os grupos AmF/NaF/SnCl2 1 (2,64 ±1,55) e 2 vezes (1,34 ±1,16), esta solução foi eficaz na redução do desgaste erosivo em comparação aos grupos NaF (4,59 ±2,13) e água destilada (4,55 ±2,75). A solução de AmF/NaF/SnCl2 demostrou se eficaz em proteger o esmalte da progressão da erosão dental, e o aumento da frequência potencializou seu efeito anti-erosivo tanto in vitro, quanto in situ. / Although several studies have shown promising results using the AmF/NaF /SnCl2 solution in inhibiting the progression of dental erosion, measures to further improve its effectiveness are fundamental. Thus, this in vitro and in situ study aimed to evaluate if the protective effect of this solution can be enhanced by increasing the frequency of use. Human enamel samples were obtained from sound human third molars; sixty for the in vitro study (4 x 4 x 1 mm), and ninety-six for the in situ (3 X 3 X 1 mm) study. After the formation of incipient erosive lesions, the in vitro samples (1% citric acid, pH 4.0, for 3 minutes), were divided into 5 treatment groups (n = 12): G1 - distilled water (negative control); G2 - NaF solution (positive control) 1x/day; G3 - NaF solution (positive control) 2x/day; G4 - AmF/NaF/SnCl2 solution 1x/day; G5 - AmF/NaF/SnCl2 solution 2x/day. The samples were then subjected to 5 days of erosive cycling through 6 daily immersions (2 minutes each) in citric acid solution (0.05 M, pH 2.6). At the end of erosive cycling, surface wear was determined by means of optical profilometry. To perform the in situ erosive challenge, the samples were also subjected to the formation of incipient lesion with the same methodology of the in vitro study. Twelve volunteers participated in the crossover in situ study - divided into four phases of 5 days each - and used a unilateral lower removable device containing 2 samples of eroded human enamel, which were changed at each phase. The samples were divided into 4 treatment groups (n = 12), the same considered for the in vitro phase, with the exception of the group of NaF solution 2x/day. During the in situ experimental phase, the device containing the sample was subjected to the erosive cycling (ex vivo), similar to the in vitro phase. At the end of each in situ experimental phase, the samples were removed from the device and analyzed by profilometry, and the average of duplicate samples were considered for statistical analysis. The ANOVA showed that the surface wear was affected by treatments evaluated in both in vitro and in situ (p?0,001) studies. In the in vitro study, the Tukey test showed no difference between the application of groups of NaF 1 (16.21 ±1.47) or 2 times (15.39 ±1.01), which showed limited reduction in wear compared to the distilled water group (20.36 ±1.56). Among the groups of AmF/NaF/SnCl2 solution, there was no difference between 1 (10.40 ±2.36) and 2 application times (7.27 ±3.29), and, although both demonstrated significantly reduced tissue loss, increasing the frequency has increased its anti-erosive potential. In the in situ phase, the NaF solution did not reveal the ability to reduce surface wear, and although there was no significant difference between the AmF/NaF/SnCl2 1 (2.64 ±1.55) and 2 times groups (1.34 ±1.16), this solution was effective in reducing the erosive wear compared to groups NaF (4.59 ±2.75) and distilled water (4.55 ±2.75). The AmF/NaF/SnCl2 solution shown to be effective in protecting the enamel progression of dental erosion, and increasing the frequency potentiate its anti-erosive effect both in vitro and in situ.

L’uranium hexafluoré (UF6), seul composé d’uranium volatil à basse température, est utilisé industriellement pour enrichir isotopiquement l’uranium afin de produire du combustible nucléaire. Cette thèse s’intéresse à trois problématiques rencontrées industriellement lors de la production d’UF6 : Celui-ci est synthétisé par l’action de fluor gazeux sur du tétrafluorure d’uranium (UF4) à haute température. Selon les conditions, cette réaction peut s’accompagner de la formation de fluorures dont la composition se situe entre UF4 et UF6, appelés fluorures d’uranium intermédiaires tels que UF5, U2F9 et U4F17 et qui viennent polluer les installations industrielles. Cette thèse permet de compléter le diagramme d’Agron qui définit les zones de stabilité des fluorures intermédiaires en fonction de la température et de la pression en UF6. Elle montre l’importance de la morphologie du solide utilisé et confirme la formation d’un nouveau fluorure intermédiaire de formule U4F19. Les fluorures d’uranium peuvent aussi former des composés en présence de polluants tels que les métaux alcalins. Les composés formés de fluorures de métaux alcalins (NaF et KF) et de tétrafluorure d’uranium ont été synthétisés. Leur fluoration par le fluor gazeux (F2) et l’UF6 a montré une oxydation de l’uranium jusqu’au degré d’oxydation V ou VI. Dans ce dernier cas de l’UF6 gazeux est produit ; mais la dissociation totale de l’uranium et de son fluorure alcalin n’a pas été observée. Enfin l’hexafluorure d’uranium est un puissant agent de corrosion notamment parce qu’il peut se dismuter et libérer du fluor. Une étude de fluoration par le fluor gazeux (F2) sur des nuances d’aciers inoxydables enrichis ou non en nickel et monel (70% Ni, 30% Cu) permet de mettre en évidence la faible résistance de ces aciers. Seul le monel présente une résistance accrue, confirmée par des essais de corrosion par UF6 qui mettent en évidence l’importance de la couche de passivation NiF2, formée par F2 avant l’attaque par UF6. Pour terminer, des études structurales réalisées à partir de diffraction des rayons X sur monocristal de composés uranifères utilisés au cours de ces études (UF4, UF5, Na7U6F31, Na7U2F15) permettent d’affiner la connaissance de ces composés. / Uranium hexafluoride (UF6), the only uranium compound volatile at low temperature, is used industrially for isotopical enrichment of uranium to produce nuclear fuel. This dissertation addresses three problems encountered industrially in the production of UF6 : It is synthesized by the action of fluorine gas (F2) on uranium tetrafluoride (UF4) at high temperature. Depending on conditions, this reaction may be accompanied by the formation of fluorides whose composition is between UF4 and UF6, called intermediate uranium fluorides such as UF5, U2F9 and U4F17 which pollute industrial facilities. This dissertation will complete Agron’s diagram which defines the stability zones of intermediate fluorides as a function of temperature and pressure of UF6. It shows the importance of the morphology of the solid used and confirms the formation of a new fluoride intermediate which formula is U4F19. The uranium fluorides can also form compounds in the presence of contaminants such as alkali metals. The compounds formed of alkali metal fluorides (NaF and KF) and uranium tetrafluoride were synthesized. Their fluorination with fluorine gas (F2) and UF6 showed an oxidation of uranium to the oxidation state V or VI. In the latter case, the UF6 gas is produced, but the total dissociation of uranium from its alkali fluoride was not observed. Finally uranium hexafluoride is a powerful agent of corrosion in particular because it can dismute and release fluoride. A study of fluorination by fluorine gas (F2) on stainless steel grades enriched or not in nickel and Monel (70% Ni, 30% Cu) is used to highlight the low resistance of steels. Only monel has a high resistance, confirmed by corrosion tests by UF6 that highlight the importance of the passivation layer NiF2, formed by F2 before the attack by UF6. Finally, structural studies carried out using X-ray diffraction on single crystal of uranium compounds used in these studies (UF4, UF5 Na7U6F31, Na7U2F15) enhance the knowledge of these compounds.

Title: Binary Signed Digit Representations of Integers in Cryptanalysis of Hash Functions Author: Jiří Vábek Department: Department of Algebra Supervisor: doc. RNDr. Jiří Tůma, DrSc., Department of Algebra Abstract: The work summarizes two main papers, A New Type of 2-block Colli- sions in MD5 and On the Number of Binary Signed Digit Representations of a Given Weight, while containing also the wider introduction to the topic of crypt- analysis of MD5 and binary signed digit representations (BSDR's). In the first paper we have implemented and applied Stevens algorithm to the newly proposed initial message differences and constructed a new type of collisions in MD5. In the second paper we have introduced and proved a new improved bound for the number of optimal BSDR's and also a new recursive bound for the number of BSDR's of a given integer with a given overweight. In addition to the results in mentioned papers, the generalized result is stated with the new bound for the number of optimal D-representations of natural numbers with D = {0, 1, 3}. Keywords: hash function, MD5, binary signed digit representation (BSDR), non- adjacent form (NAF) 1

Apesar de diversos estudos demonstrarem resultados promissores da utilização da solução de AmF/NaF/SnCl2 na inibição da progressão da lesão de erosão dental, medidas que visam melhorar ainda mais sua eficácia são fundamentais. Sendo assim, este estudo in vitro e in situ se propôs a avaliar se o efeito protetor dessa solução pode ser potencializado pelo aumento da frequência de uso. Para tanto, foram obtidas, a partir de terceiros molares humanos hígidos, sessenta amostras de esmalte dental humano para o estudo in vitro (4 X 4 X 1 mm), e noventa e seis para o in situ (3 X 3 X 1 mm). Após a formação de lesão erosiva incipiente nas amostras in vitro, (ácido cítrico a 1%, pH 4,0, durante 3 minutos), estas foram divididas nos 5 grupos de tratamentos (n=12): G1 - água destilada (controle negativo); G2 - solução de NaF (controle positivo) 1x/dia; G3 - solução de NaF (controle positivo) 2x/dia; G4 - solução de AmF/NaF/SnCl2 1x/dia; G5 - solução de AmF/NaF/SnCl2 2x/dia. As amostras foram então submetidas a 5 dias de ciclagem erosiva através de 6 imersões diárias de 2 minutos em solução de ácido cítrico (0,05M, pH 2.6). Ao final da ciclagem erosiva, foi realizada a determinação do desgaste de superfície por meio de Perfilometria óptica. Para realização do desafio erosivo in situ, as amostras também foram submetidas à formação da lesão incipiente, com a mesma metodologia do in vitro. Doze voluntários participaram do estudo in situ e cruzado, dividido em quatro fases de 5 dias cada, os quais utilizaram um dispositivo removível inferior unilateral contendo 2 amostras de esmalte dental humano erodido, que foram trocadas a cada fase. As amostras foram divididas em 4 grupos de tratamentos (n=12), os mesmos utilizados na etapa in vitro, com exceção do grupo da solução de NaF 2x/dia. Durante a fase experimental in situ o dispositivo contendo as amostras foi submetido à ciclagem erosiva (ex vivo) semelhante à etapa in vitro. Ao final de cada fase experimental in situ, as amostras foram removidas do dispositivo e analisadas através de perfilometria, e foram consideradas as médias das amostras em duplicata para a análise estatística. A ANOVA mostrou que o desgaste superficial foi afetado pelos tratamentos avaliados tanto in vitro quanto in situ (p?0,001), com nível de significância de 5%. No estudo in vitro, o teste de Tukey demonstrou que não houve diferença entre os grupos de aplicação do NaF 1 (16,21 ±1,56) ou 2 vezes (15,39 ±1,01), que apresentaram redução limitada no desgaste quando comparado ao grupo da água destilada (20,36 ±1,56); já entre os grupos da solução AmF/NaF/SnCl2 houve diferença entre aplicação 1 (10,40 ±2,36) e 2 vezes (7,27 ±3,29), e que apesar de ambos demonstrarem redução significativa da perda de substrato, o aumento da frequência aumentou este potencial anti-erosivo. Na parte in situ, a solução de NaF não demonstrou capacidade de reduzir o desgaste, e apesar de não ter havido diferença significante entre os grupos AmF/NaF/SnCl2 1 (2,64 ±1,55) e 2 vezes (1,34 ±1,16), esta solução foi eficaz na redução do desgaste erosivo em comparação aos grupos NaF (4,59 ±2,13) e água destilada (4,55 ±2,75). A solução de AmF/NaF/SnCl2 demostrou se eficaz em proteger o esmalte da progressão da erosão dental, e o aumento da frequência potencializou seu efeito anti-erosivo tanto in vitro, quanto in situ. / Although several studies have shown promising results using the AmF/NaF /SnCl2 solution in inhibiting the progression of dental erosion, measures to further improve its effectiveness are fundamental. Thus, this in vitro and in situ study aimed to evaluate if the protective effect of this solution can be enhanced by increasing the frequency of use. Human enamel samples were obtained from sound human third molars; sixty for the in vitro study (4 x 4 x 1 mm), and ninety-six for the in situ (3 X 3 X 1 mm) study. After the formation of incipient erosive lesions, the in vitro samples (1% citric acid, pH 4.0, for 3 minutes), were divided into 5 treatment groups (n = 12): G1 - distilled water (negative control); G2 - NaF solution (positive control) 1x/day; G3 - NaF solution (positive control) 2x/day; G4 - AmF/NaF/SnCl2 solution 1x/day; G5 - AmF/NaF/SnCl2 solution 2x/day. The samples were then subjected to 5 days of erosive cycling through 6 daily immersions (2 minutes each) in citric acid solution (0.05 M, pH 2.6). At the end of erosive cycling, surface wear was determined by means of optical profilometry. To perform the in situ erosive challenge, the samples were also subjected to the formation of incipient lesion with the same methodology of the in vitro study. Twelve volunteers participated in the crossover in situ study - divided into four phases of 5 days each - and used a unilateral lower removable device containing 2 samples of eroded human enamel, which were changed at each phase. The samples were divided into 4 treatment groups (n = 12), the same considered for the in vitro phase, with the exception of the group of NaF solution 2x/day. During the in situ experimental phase, the device containing the sample was subjected to the erosive cycling (ex vivo), similar to the in vitro phase. At the end of each in situ experimental phase, the samples were removed from the device and analyzed by profilometry, and the average of duplicate samples were considered for statistical analysis. The ANOVA showed that the surface wear was affected by treatments evaluated in both in vitro and in situ (p?0,001) studies. In the in vitro study, the Tukey test showed no difference between the application of groups of NaF 1 (16.21 ±1.47) or 2 times (15.39 ±1.01), which showed limited reduction in wear compared to the distilled water group (20.36 ±1.56). Among the groups of AmF/NaF/SnCl2 solution, there was no difference between 1 (10.40 ±2.36) and 2 application times (7.27 ±3.29), and, although both demonstrated significantly reduced tissue loss, increasing the frequency has increased its anti-erosive potential. In the in situ phase, the NaF solution did not reveal the ability to reduce surface wear, and although there was no significant difference between the AmF/NaF/SnCl2 1 (2.64 ±1.55) and 2 times groups (1.34 ±1.16), this solution was effective in reducing the erosive wear compared to groups NaF (4.59 ±2.75) and distilled water (4.55 ±2.75). The AmF/NaF/SnCl2 solution shown to be effective in protecting the enamel progression of dental erosion, and increasing the frequency potentiate its anti-erosive effect both in vitro and in situ.