Com o objetivo de avaliar a influência do hidróxido de cálcio e do EDTA na marcação da infiltração marginal de corante azul de metileno a 2% em canais radiculares obturados pela técnica da condensação lateral, foram empregados 188 dentes incisivos centrais superiores humanos extraídos. Após serem instrumentados e impermeabilizados, foram divididos em 3 grupos de 60 elementos cada, sendo que outros 8 dentes foram utilizados como controle. Cada grupo foi dividido em 2 subgrupos, os quais, foram subdivididos em dois, totalizando 12 subgrupos com 15 elementos cada, dessa forma descritos: Grupo I – obturação imediata; em 30 dentes foi aplicado EDTA por 3 minutos antes da obturação; em 30 dentes a obturação foi feita sem a aplicação do EDTA; 30 dentes foram obturados com cimento de óxido de zinco e eugenol e 30 obturados com pasta de hidróxido de cálcio; Grupo II – aplicação de EDTA por 3 minutos e preenchimento de todos os canais com pasta de hidróxido de cálcio (curativo); em 30 dentes o EDTA foi reaplicado após a remoção do curativo, e nos outros 30 dentes não; 30 dentes foram obturados com cimento de óxido de zinco e eugenol e 30 obturados com pasta de hidróxido de cálcio; Grupo III – após a instrumentação, os canais foram preenchidos com pasta de hidróxido de cálcio (curativo) sem a aplicação prévia do EDTA; após a remoção do curativo, em 30 dentes o EDTA foi aplicado e em outros 30 não; 30 dentes foram obturados com cimento de óxido de zinco e eugenol e outros 30 com pasta de hidróxido de cálcio. Posteriormente à imersão em azul de metileno a 2% por 72 horas, os dentes foram seccionados longitudinalmente e as infiltrações mensuradas com o emprego de um microscópio óptico munido de uma ocular micrometrada. Após serem empregados os testes estatísticos pertinentes, foram obtidas as seguintes conclusões: - em relação ao hidróxido de cálcio: como curativo e pasta obturadora, interfere estatisticamente na marcação da infiltração, diminuindo a sua magnitude; em relação ao EDTA: o seu emprego prévio ao curativo de hidróxido de cálcio, melhora o selamento das obturações com óxido de zinco e eugenol; o emprego antes e após o curativo, promove um aumento da infiltração em canais obturados com óxido de zinco e eugenol; em canais obturados com pasta de hidróxido de cálcio, o seu emprego não promove interferências estatisticamente significantes nos resultados. / With the objective of evaluate the influence of calcium hydroxide and EDTA in marginal infiltration of metilen blue 2% in root canals obturated by the laterally condensed technique, were used 188 central superior incisor human teeth. After they were instrumented and impatented, the 188 teeth were divided in 3 groups of 60 teeth each. Each group was divided in 2 subgroups and these were divided again in 2, resulting 12 subgroups with 15 teeth each, this way discribed: Group I: immediate obturation; in 30 teeth was applied EDTA for 3 minutes before obturation; and in the other 30 the obturation was done without application of EDTA. 30 teeth were obturated with zinc oxide and eugenol ciment and 30 were obturated with calcium hydroxide paste; Group II: application of EDTA for 3 minutes and all root canals were filled with calcium hydroxide paste (bandage). In 30 teeth the EDTA was applied again after removing the bandage, but this was not done in the other 30; 30 teeth were obturated with calcium hydroxide paste; Group III: the root canals were filled with calcium hydroxide paste (bandage), without a previous application of EDTA, after they were instrumented. After removing the bandage, the EDTA was applied in 30 teeth one more time but not the other 30; 30 teeth were obturated with zinc oxide and eugenol ciment and the other 30 with calcium hydroxide paste. After the immersion in metilen blue 2% for 72 hours, all the 180 teeth were longitudinally sectionalized and the infiltrations were measured using a stereomicroscope and a micrometric ocular. Statistics tests were done and according with those, the following conclusions were obtained: - calcium hydroxide: As a bandage and as an obturation paste, interferes in the infiltration; its use as a bandage, before obturation, with zinc oxide and eugenol ciment, improves the sealer quality of this last one; - EDTA: Its use before the calcium hydroxide bandage, improves obturation sealings with zinc oxide and eugenol ciment. It use after and before the bandage promotis an infiltration increasing in obturated root canals with zinc oxide and eugenol ciment; in root canals obturated with calcium hydroxide paste, the use of EDTA does not promote significative interferences in the result.

Submitted by Mirian Silva (mirian.pereira@uniceub.br) on 2015-10-08T23:33:03Z No. of bitstreams: 1 Influencia do tempo (6) ok.pdf: 358016 bytes, checksum: 31f9923438aa951579acb64080ccce3b (MD5) / Made available in DSpace on 2015-10-08T23:33:03Z (GMT). No. of bitstreams: 1 Influencia do tempo (6) ok.pdf: 358016 bytes, checksum: 31f9923438aa951579acb64080ccce3b (MD5) Previous issue date: 2012 / A dosagem da glicemia é empregada para estudo do metabolismo da glicose tanto no controle de produção, consumo e também no armazenamento, assim podem ser diagnosticados os diversos estados de hiperglicemia e hipoglicemia, podendo ser medidos por exames laboratoriais utilizando sangue venoso. É visto que após a coleta do sangue, as células sanguíneas continuam a degradar a glicose gerando um decréscimo de aproximadamente 10mg/dL por hora à temperatura ambiente a não ser que se adicione um preservativo, sendo o fluoreto o mais indicado por ser inibidor da glicólise. Este estudo teve por objetivo comparar o uso de dois anticoagulantes diferentes (fluoreto e EDTA) para avaliar a estabilidade da glicemia em temperatura ambiente e ainda correlacionar as glicemias obtidas para os dois tipos de anticoagulantes determinando a diferença entre elas devido ao fator de tempo. Para a realização do trabalho foram coletadas 30 amostras de sangue total por punção venosa de voluntários de ambos os sexos sem restrição de idade e sem necessidade de jejum. Os resultados obtidos confirmaram que na primeira hora houve a queda de aproximadamente 10mg/dL para os dois anticoagulantes utilizados, seguido de estabilização com o anticoagulante fluoreto e um decréscimo progressivo com o uso do anticoagulante EDTA. Isto concorda com o fato de que o tempo é um fator determinante na dosagem da glicemia influenciando na estabilidade da amostra e na confiabilidade dos resultados podendo gerar resultados não verdadeiros.

Introduction: It is recommended to place all the vacuum tubes directly on a sample cradle after vein puncture to prevent analytic error. This recommendation is not always easy to follow because the samples are taken by different professionals under different situations.  The three most common analyses, platelets count, haemoglobin and prothrombin time were tested.  Therefore, it was interesting to compare results from the three most common analyses with or without sample cradle, to evaluate the influence of this step on the result. Methods: Three analyses were preformed, using blood from 50 different persons. Each person gave two vacuum tubes, each contained 4.5mL of venous blood for the study. Tubes containing EDTA were used for platelet counts and measurement of haemoglobin and tubes containing citrate were used for prothrombin time-analysis. One of the tubes was placed, as recommended, directly on the sample cradle while the other tube was placed flat on a bench for 10 minutes before it was placed on the sample cradle. Results: There was a clear difference in platelet counts with and without immediate cradling but only minor difference between the results for haemoglobin and International Normalized Ratio. Conclusion: Some analyses seem to be more sensitive for variation in cradling than others. For platelet count it was important to immediately rock the tubes but for determination of prothrombine time and hemoglobin it had a small impact. The small impact on the results is probably due to the efficiency of the anticoagulant in the vacuum tubes.

Ethylene oxide (EO) is a very versatile compound with considerable energy in its ring structure. Its reactions proceed mainly via ring opening and are highly exothermic. Under some conditions, it is known to undergo a variety of reactions, such as isomerization, polymerization, hydrolysis, combustion and decomposition Due to its very reactive characteristic and widely industrial applications, EO has been involved in a number of serious incidents such as Doe Run 1962, Freeport 1974, Deer Park 1988 and Union Carbide Corporation’s Seadrift 1991. The impacts can be severe in terms of death and injury to people, damage to physical property and effects on the environment. For instance, the Union Carbide incident in 1991 caused one fatality and extensive damage to the plant with the property damage of up to 80 million dollars. Contamination has a considerable impact on EO reactivity by accelerating substantially its decomposition and playing a key role on EO incidents. In this work, the reactivity of EO with contaminants such as KOH, NaOH, NH4OH, and EDTA is evaluated. Useful information that is critical to the design and operation of safer chemical plant processes was generated such as safe storage temperatures (onset temperature), maximum temperature, maximum pressure, temperature vs. time, heat and pressure generation rates as a function of temperature and time to maximum rate using adiabatic calorimetry. A special arrangement for the filling-up of the cell was constructed due to the gaseous nature and toxicity of EO. A comparison of their thermal behavior is also presented since several contaminants are studied.

Density gradient ultracentrifugation (DGU) is a powerful method for analyzing lipoprotein particles in great detail. It yields considerable amounts of information regarding the density distribution of these particles when coupled with fluorometric analysis and is an invaluable tool in determining their relative abundance. This union allows relationships between subclasses of lipoproteins to be established that gives researchers a more focused path to aid them in developing methods to predict the early onset of coronary artery disease (CAD). The research presented here focuses on the pairing of DGU with post-separatory techniques including matrix-assisted laser desorption mass spectrometry (MALDI-MS), liquid chromatography mass spectrometry (LC-MS), capillary electrophoresis (CE), isoelectric focusing (IEF) and apoptosis studies involving cell cultures. It is becoming clearer that cholesterol concentrations themselves do not provide sufficient data to assess the quality of cardiovascular health. As a result, research is becoming more focused on identifying better markers that may be indicative of development of CAD in a patient. Of specific interest is group of particles known as high density lipoproteins (HDL). Classically, this molecule is considered the “good cholesterol”, but literature from the last decade suggests that there may be atherogenic variants to this group. By utilizing DGU as a preparatory method for secondary analyses, new dimensions can be added to the density distribution analysis to allow a better determination of markers of cardiovascular health. The aim of this work is to utilize the principles involved with these various techniques to develop a comprehensive set of methods to aid in the detection of potential risk markers. In this study, the properties of metal ion complexes of EDTA as solute systems for analysis of lipoproteins by DGU are analyzed. We show that by varying the complexing ion and counter-ion of these metal-ion complexes, we gain the ability to control the separation of lipoprotein subclasses for subsequent analyses. Qualitative and quantitative data is presented that describes the analysis of different density regions of HDL for apolipoprotein content. Trends between control and atherogenic samples are also described and a clinical link between the biological activity of these regions and the chemical analysis is discussed.

This study was to investigate the removal efficiency and the feasibility of containing-EDTA solutions by O3 and O3/UV, advanced oxidation processes (denoted by AOPs). The operation parameters conducted in semi-batch reactor were as follows: ozone dose, pH, temperature and initial concentration of EDTA. The best mineralization and COD removal was found at pH= 9 when the pH values in O3 process was controlled at 3, 5, 7, 9 and 11. Addition of UV in O3 process for treating solutions containing EDTA was found not increasing the reaction rate but raising the COD and mineralization efficiency. In O3 process, the reaction rate was proportional to the ozone dose, it caused a higher mineralization. The higher the initial concentration of EDTA, the lower reaction rate, and the decreasing the mineralization was. Changing the temperature in reaction process was not obviously affected the removal of EDTA due to the lower activated energy found in O3 process. In O3/UV process, EDTA was decomposed very fast, but it still could not be mineralized the intermediates completely. The concentration of nitrate formed in this process was low. It is probably for high energy NH-containing bonds which is not easy break down by O3/UV. Thus, the major reactions in this process are the break of C-N bond, and followed by the break of C-H bond.

Bitumen-derived heavy gas oil contains large amounts of sulfur (~4.0 wt.%) and nitrogen (~0.4 wt.%), which need to be lowered before it becomes suitable as a feedstock for refineries. The most widely used upgrading process is hydrotreating, and the conventional catalyst used for hydrotreating is Ni or Co and Mo or W supported on γ-Al2O3. Additionally, environmentally driven regulations impose strict limits on sulfur and nitrogen levels in transportation fuels. Therefore, the main focus of this work was to enhance the activity of a NiMo supported catalyst through its modification and to improve its selectivity to removal of bulky sulfur- and nitrogen-containing compounds from heavy gas oil under industrial hydrotreating conditions. This work was divided into four phases, and this thesis summarizes the research outcomes of each phase. The first phase examined the effects of chelating ligands, specifically, ethylenediaminetetraacetic acid (EDTA), on hydrotreating activity and the sulfidation mechanism. EDTA was seen to have a beneficial effect on hydrotreating activity. Detailed mechanistic aspects of interactions between support and EDTA, EDTA and metallic species, support and metal, support and active phase, and metallic species and metallic species at different reaction conditions, were also studied. Characterization by XANES revealed that the presence of a chelating agent delayed nickel sulfidation, which was the main cause of improvement in hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) activities. It also showed that EDTA plays a role in redistribution of active phases during sulfidation and favors the formation of octahedral molybdenum oxides. The second phase studied the effects of support modification and combinations of different supports and EDTA. In this phase, several mesoporous materials, including M-SBA-15 (M= Al, Ti and Zr), mesoporous mixed metal oxides (TiO2-Al2O3, ZrO2-Al2O3 andSnO2-Al2O3) and mesoporous metal oxides (ZrO2, Al2O3), were synthesized and used as support materials for a NiMo catalyst. NiMo/M-SBA-15 catalysts showed higher HDS and HDN activities and, the increase in activity is attributed to incorporation of heteroatoms in an SBA-15 matrix, which resulted in increase in metal support interaction, acidic strength and dispersion of active metals. The addition of EDTA to these catalysts helps in the formation of octahedral molybdenum oxide, which are easily reducible during sulfidation. This is evident from the XANES Mo LIII-edge study of the oxide catalysts. The increase in hydrodenitrogenation (HDN), hydrodesulfurization (HDS) and hydrodearomatization (HDA) activities as compared to that shown by the NiMo/γ-Al2O3 catalyst were also observed on addition of EDTA in large-pore, high-surface-area mesoporous zirconia supported NiMo catalysts. The incorporation of different metal oxides in alumina, as in the case of mixed metal oxides, resulted in a change in acidic strength and metal support interactions. It was observed with acridine-FTIR analysis that the catalysts with higher acidic strength tightly held acridine at high temperatures. This implies that catalysts with higher acidity are prone to inhibition by nitrogen-containing compounds present in feed, which will affect catalytic activity. The HDS and HDN activities for hydrotreating of heavy gas oil suggest that mesoporous alumina and titania-alumina supported catalysts perform better as compared to the conventional NiMo/γ-Al2O3 catalyst. Therefore, the effects of EDTA to Ni molar ratio (EDTA/Ni = 0 to 2) on the activities of the NiMo/MesoAl2O3 and NiMo/MesoTiO2-Al2O3 catalysts were studied, and EDTA was observed to have a negative impact on catalytic activity for these catalysts. This is attributed to a decrease in the active metal dispersion in these catalysts caused by the addition of EDTA. The catalysts NiMo/MesoAl2O3 and NiMo/MesoTiO2-Al2O3 without EDTA showed high active metal dispersion due to their high surface area and ordered structure. The third phase studied the combined effects of phosphorus and EDTA on the hydrotreating activity of NiMo supported catalysts. The effects of method of phosphorus addition (sequential and co-impregnation method) were also studied. When phosphorus was added using a co-impregnation method, as in the catalyst NiMoP/MesoAl2O3(CI), an increase in HDN, HDA and HDS activities was observed. However, the catalysts containing both EDTA and phosphorus showed a decrease in HDS and HDN activities. The fourth phase included a kinetic study using the Power Law and L-H models. The catalyst, NiMoP/mesoAl2O3(CI), was found to have higher HDN and HDS activities as compared to a conventional γ-Al2O3 supported catalyst containing phosphorus.

Orientador: José Eduardo Cezar Sampaio / Banca: Carlos Rossa Júnior / Banca: Gibson Luis Pilatti / Resumo: O propósito deste estudo foi avaliar in vitro a eficácia de um gel de EDTA associado ao detergente texapon na remoção da "smear layer" avaliando-se os fatores concentração da substância, tempo e forma de aplicação. "Smear layer" foi produzida experimentalmente em dentes extraídos. As amostras obtidas receberam a aplicação do gel de EDTA nas seguintes concentrações: controle (soro fisiológico), 5%, 10%, 15%, 20%, 24%. Para cada grupo experimental os tempos de aplicação foram de um, dois e três minutos. Quanto à forma de aplicação, foram testadas as maneiras passiva e ativa (pincel). A seguir foram obtidas fotomicrografias em microscópio eletrônico de varredura que foram avaliadas segundo o índice de Sampaio (1999). Os resultados demonstraram que a utilização do gel de EDTA-T removeu mais "smear layer" que o grupo controle. Durante a aplicação passiva, a concentração de 15% foi superior a de 5% e 10%, diferença que não existia durante a aplicação ativa. O tempo de três minutos parece ser o ideal para aplicação do gel de EDTA-T. A forma de aplicação ativa é superior a forma de aplicação passiva. A forma de aplicação parece ser o fator fundamental na remoção da "smear layer", pois influencia os fatores concentração e tempo de aplicação e não é influenciado por eles. / Abstract: The purpose of this study was to evaluate in vitro the efficacy of na EDTA-T gel on smear layer removal evaluating the influence of concentration, application time and application manner. Smear layer was experimentally promoved at extracted teeth. The root fragments assigned one of the EDTA gel concentration tested: control, 5%, 10%, 15%, 20% and 24% . For each concentration, the gel was applied for one, two and three minutes, either in a passive or active manner. Photomicrographs was obtained with scanning electron microscope, which were evaluated using index of Sampaio (1999). The results demonstrated that the EDTA-T gel exhibitted a better smear layer removal than control. During the passive application, concentration of 15% was superior compared to 5% and 10% concentration, but when active application was used, there was no differenceamong the groups. Smear layer removal was more effective when EDTA gel was applied for three minutes. Application manner is the fundamental factor on smear layer removal because influenced concentration and application time and was not influenced by them. / Mestre

Made available in DSpace on 2016-06-02T20:34:16Z (GMT). No. of bitstreams: 1 2122.pdf: 6004420 bytes, checksum: 56935670528874bab07b7664204b81ee (MD5) Previous issue date: 2008-08-26 / Universidade Federal de Minas Gerais / The purpose of this thesis was to establish the conditions for silver-copper and silver-zinc electrodeposition from ammonium hydroxide and thiourea solutions, respectively, and to investigate the effect of added EDTA and HEDTA on the electrodeposition process. In this way, the influence of solution composition and electrodeposition parameter (deposition potential, deposition charge density, and deposition current density) on the electrodeposition process of silver-copper and silver-zinc was investigated. Relation between chemical species in solution and the reactions at the cathode/solution interface was established. It was verified that the formation of silver(I) complexes with ammonia or thiourea shifted the silver deposition potential to more negative value. As a result, the codeposition of silver and copper or silver and zinc was facilitated. On the other hand, EDTA and HEDTA acted as inhibitor of dendritic growth. This inhibition was attributed to EDTA and HEDTA adsorption on the platinum surface and growth sites of the electrodeposit, which decreased the current density of the charge transfer process. The silver-copper electrodeposit composition was a function of solution composition and electrodeposition parameter. On the other hand, the silver-zinc electrodeposit composition was almost constant, irrespective of the electrodeposition condition. Besides, the silver-copper electrodeposit was amorphous and composed by a mixture of silver, copper and silver-copper supersaturated solid solution. Sulphur was incorporated into the silver-zinc electrodeposit due to alkaline hydrolysis of thiourea in the cathode/solution interface. The silver-zinc electrodeposit was amorphous due to sulphur incorporation. / O propósito desta tese foi estabelecer as condições para eletrodeposição de prata-cobre e prata-zinco a partir de soluções de hidróxido de amônio e tiouréia, respectivamente, e investigar o efeito da adição de EDTA e HEDTA no processo de eletrodeposição. Deste modo, investigou-se a influência de composição de solução e parâmetro de eletrodeposição (potencial de deposição, densidade de carga de deposição e densidade de corrente de deposição) sobre o processo de eletrodeposição de prata-cobre e prata-zinco. Estabeleceu-se relação entre as espécies químicas em solução e as reações que ocorreram na interface cátodo/solução. Verificou-se que a formação de íons complexos de prata(I) com amônia ou tiouréia deslocou o potencial de deposição de prata para valor mais negativo. Como resultado, a codeposição de prata e cobre ou prata e zinco foi facilitada. Por outro lado, EDTA e HEDTA atuaram como inibidores de crescimento dendrítico. Esta inibição foi atribuída à adsorção de EDTA e HEDTA sobre a platina e sítios de crescimento, a qual diminui a densidade de carga do processo de transferência de carga. A composição do eletrodepósito de prata-cobre foi uma função da composição da solução e do parâmetro de eletrodeposição. Por outro lado, a composição do eletrodepósito de prata-zinco foi quase constante, independentemente da condição de eletrodeposição. Ademais, o eletrodepósito de prata-cobre foi amorfo e composto por mistura de prata, cobre e solução sólida supersaturada de prata-cobre. Enxofre foi incorporado ao eletrodepósito de prata-zinco devido à hidrólise alcalina de tiouréia na interface cátodo/solução. O eletrodepósito de prata-zinco foi amorfo devido à incorporação de enxofre.

Made available in DSpace on 2016-06-02T20:36:20Z (GMT). No. of bitstreams: 1 1915.pdf: 869538 bytes, checksum: b9fcf9bcdb8ec116cd5fad0e482efe72 (MD5) Previous issue date: 2007-07-27 / Universidade Federal de Sao Carlos / In this work a Cu/CuY2- indicator system was used to carry out potentiometric titrations of Cu2+, Co2+, Cd2+, Zn2+ and Mn2+ ions with EDTA solution. A copper wire with 8.32 cm2 of superficial area was used as an indicator electrode. The CuY2- complex was synthesized by reaction between cupric oxide (CuO) and EDTA standard solution (H2Y2-) at a temperature of 85 oC. The titrations were performed in the presence of small concentration of the CuY2- complex. The Cu2+, Co2+, Cd2+ and Zn2+ ions were titrated in sodium acetate buffer solution (pH 4.80) and Mn2+ in TRIS-HCl buffer solution (pH 8.90). A modification in a conventional method for titration of metallic cations with EDTA solutions was performed to improve the response of the system. The modification includes addition of buffer species to the titrant solution. The buffer specie used to prepare solutions was sodium acetate. The influence of the concentration of CuY2- added in the titration performance was investigated and a relation of nM2+/nCuY2- equal or greater than 5 should be used for a better response. During this work other studies were performed, such as the method to obtain carbonate-free sodium and potassium hydroxides solutions as well as the method for the standardization of EDTA solid reagent, Na2H2Y, to employing as secondary standard in the directly preparation of EDTA solution. / Neste trabalho foram realizadas titulações potenciométricas dos íons Cu2+, Co2+, Cd2+, Zn2+ e Mn2+ com EDTA utilizando um sistema indicador de Cu/CuY2-. O eletrodo indicador utilizado foi um fio de cobre com área superficial de aproximadamente 8,32 cm2 em meio contendo CuY2-. A síntese do complexo CuY2- foi baseada na reação entre óxido cúprico, CuO e solução padrão de EDTA, H2Y2- mantendo aquecimento de 85 oC. As titulações foram realizadas na presença de pequena quantidade de complexo CuY2-, sendo que os íons Cu2+, Co2+, Cd2+ e Zn2+ foram titulados em meio de tampão acetato pH 4,80 e os íons Mn2+ em meio de tampão TRIS-HCl pH 8,90. Uma mudança na metodologia original foi realizada, na qual os cátions metálicos estudados foram titulados com soluções de EDTA autotamponantes, isto é, titulantes que apresentam espécies tampão em sua composição. A espécie tampão utilizada no preparo das soluções foi o acetato. A influência da quantidade de complexo CuY2- adicionado durante as titulações também foi estudado, concluindo que a relação nM2+/nCuY2- deve ser maior ou igual a 5. Durante o desenvolvimento do trabalho, foram propostos também um novo método para o preparo de soluções de hidróxido de sódio e potássio livre de íons carbonato (CO3 2-) como também, uma metodologia para a padronização do sólido di-sódico de EDTA, Na2H2Y, permitindo assim o emprego deste sólido como padrão secundário no preparo imediato de suas respectivas soluções.