This thesis describes the synthesis, characterization, and application of metal-chelating polymers for mass-cytometric bioassays. Mass cytometry is a cell characterization technique in which cells are injected individually into an ICP-MS detector. Signal is provided by staining cell-surface or intracellular antigens with metal-labeled antibodies (Abs). These Abs are labeled through the covalent attachment of metal-chelating polymers which carry multiple copies of a lanthanide isotope. In this work, my first goal was to develop a facile, straightforward synthesis of a new generation of metal-chelating polymers. The synthesis began with reversible addition-fragmentation chain transfer polymerization, and was followed by numerous post-polymerization pendant group transformations to introduce DTPA lanthanide chelators to every repeat unit, and a maleimide at the end of the chain. The second goal was to apply these metal-chelating polymers in bioassay experiments. The DTPA groups were loaded with lanthanide ions, and the maleimide group was used to covalently attach the polymer to an Ab. This goat anti-mouse conjugate was found to carry an average of 2.4 ± 0.3 polymer chains. Then, primary Ab conjugates were prepared and used in an 11-plex mass cytometry assay in the characterization of umbilical cord blood cells. The third goal was to expand the multiplexity of the assay. In current technology, the number of Abs that can be monitored simultaneously is limited to the 31 commercially available, stable lanthanide isotopes. Thus, I had an interest in preparing metal-chelating polymers that could carry other metals in the 100-220 amu range. I synthesized polymers with four different polyaminocarboxylate ligands, and investigated the loading of palladium and platinum ions into these polymers. Polymer-Ab conjugates prepared with palladium- and platinum-loaded polymers gave curious results, in that only dead cells were recognized. The fourth goal was to create dual-purpose Ab tags. My approach was to synthesize polymers similar to those described above, but which also carried two to six fluorescent dyes. Polymer-Ab conjugates prepared with four different dye-labeled polymers gave mixed results. Two of the four conjugates performed well in FACS and mass cytometric assays, but the other two did not. Further experiments are needed to overcome this problem.

This thesis describes the synthesis, characterization, and application of metal-chelating polymers for mass-cytometric bioassays. Mass cytometry is a cell characterization technique in which cells are injected individually into an ICP-MS detector. Signal is provided by staining cell-surface or intracellular antigens with metal-labeled antibodies (Abs). These Abs are labeled through the covalent attachment of metal-chelating polymers which carry multiple copies of a lanthanide isotope. In this work, my first goal was to develop a facile, straightforward synthesis of a new generation of metal-chelating polymers. The synthesis began with reversible addition-fragmentation chain transfer polymerization, and was followed by numerous post-polymerization pendant group transformations to introduce DTPA lanthanide chelators to every repeat unit, and a maleimide at the end of the chain. The second goal was to apply these metal-chelating polymers in bioassay experiments. The DTPA groups were loaded with lanthanide ions, and the maleimide group was used to covalently attach the polymer to an Ab. This goat anti-mouse conjugate was found to carry an average of 2.4 ± 0.3 polymer chains. Then, primary Ab conjugates were prepared and used in an 11-plex mass cytometry assay in the characterization of umbilical cord blood cells. The third goal was to expand the multiplexity of the assay. In current technology, the number of Abs that can be monitored simultaneously is limited to the 31 commercially available, stable lanthanide isotopes. Thus, I had an interest in preparing metal-chelating polymers that could carry other metals in the 100-220 amu range. I synthesized polymers with four different polyaminocarboxylate ligands, and investigated the loading of palladium and platinum ions into these polymers. Polymer-Ab conjugates prepared with palladium- and platinum-loaded polymers gave curious results, in that only dead cells were recognized. The fourth goal was to create dual-purpose Ab tags. My approach was to synthesize polymers similar to those described above, but which also carried two to six fluorescent dyes. Polymer-Ab conjugates prepared with four different dye-labeled polymers gave mixed results. Two of the four conjugates performed well in FACS and mass cytometric assays, but the other two did not. Further experiments are needed to overcome this problem.

Iron precipitation during matrix acidizing treatments is a well-known problem. During matrix acidizing, successful iron control can be critical to the success of the treatment. Extensive literature review highlighted that no systematic study was conducted to determine where this iron precipitates, the factors that affect this precipitation, and the magnitude of the resulting damage. Iron (III) precipitation occurs when acids are spent and the pH rises above 1, which can cause severe formation damage. Chelating agents are used during these treatments to minimize iron precipitation. Disadvantages of currently used chelating agents include limited solubility in strong acids, low thermal stability, and/or poor biodegradability. In this study, different factors affecting iron precipitation in Indiana limestone rocks were examined. Two chelating agents, GLDA and HEDTA, were tested at different conditions to assess their iron control ability. Results show that a significant amount of iron precipitated, producing a minimal or no gain in the final permeability, this indicated severe formation damage. The damage increased with the increase of the amount of iron in solution. When chelating agents were used, the amount of iron recovered depended on both chelate-to-iron mole ratio and the initial permeability of the cores. Calcium is chelated along with iron, which limits the effectiveness of chelating agents to control iron (III) precipitation. Acid solutions should be designed considering this important finding for more successful treatments.

Sandstone acidizing has been carried out with mud acid which combines hydrochloric acid and hydrofluoric acid at various ratios. The application of mud acid in sandstone formations has presented quite a large number of difficulties like corrosion, precipitation of reaction products, matrix deconsolidation, decomposition of clays by HCl, and fast spending of the acids. There has been a recent trend to use chelating agents for stimulation in place of mud acid which are used in oil industry widely for iron control operations. In this study, two chelates, L-glutamic-N, N-diacetic acid (GLDA) and hydroxyethylethylene-diaminetriacetic acid (HEDTA) have been studied as an alternative to mud acid for acidizing. In order to analyze their performance in the application of acidizing, coreflood tests were performed on Berea and Bandera sandstone cores. Another disadvantage of mud acid has been the fast spending at clay mineral surfaces leading to depletion of acid strength, migration of fines, and formation of colloidal silica gel residue. Hence, compatibility of chelates with clay minerals was investigated through the static solubility tests. GLDA and HEDTA were analyzed for their permeability enhancement properties in Berea and Bandera cores. In the coreflood experiments conducted, it was found out that chelating agents can successfully stimulate sandstone formations. The final permeability of the Berea and Bandera cores were enhanced significantly. GLDA performed better than HEDTA in all applications. The substitution of seawater in place of deionized water for mixing purposes also led to an increased conductivity of the core implying GLDA is compatible with seawater. In the static solubility tests, chelates were mixed with HF acid at various concentrations. GLDA fluids kept more amounts of minerals in the solution when compared with HEDTA fluids. Sodium-based chelates when mixed with HF acid showed inhibited performance due to the formation of sodium fluorosilicates precipitates which are insoluble damage creating compounds. The application of ammonium-based chelate with HF acid was able to bring a large amount of aluminosilciates into the solution. The study recommends the use of ammonium-based GLDA in acidizing operations involving HF acid and sodium-based GLDA in the absence of the acid.

Abstract Information about interactions among metals, hydrogen peroxide and chelating agents is needed to develop environmental technology and the operating efficiency of modern elemental chlorine free and total chlorine free bleaching processes. The work presented here focused on the properties of metal chelates and corrosion of titanium in an alkaline hydrogen peroxide solution. A comparative study between three rapid analysis methods, ICP-AES, XRF and ISE, was performed in pulp matrix and error sources of ISE were investigated in detail. Sensitive and selective GC methods for chelating agents ADA and NTA in water matrices were developed. Decomposition of ADA (percentage of residual 71) was observed already at the hydrogen peroxide anion level of 400 mg/l in which DTPA was more persistent (percentage of residual 94). EDTA was stable even in the hydrogen peroxide anion level of 1200 mg/l, in which its percentage of residual was 94. DTPA, EDTA and ADA were more soluble in the presence of iron and manganese than in the absence of these metals. The chelation of iron appeared to be thermodynamically limited in hydrogen peroxide bleaching conditions. Unalloyed (Grade 2) and alloyed (Grade 5) titanium corroded at the hydrogen peroxide anion level of 200 mg/l. The presence of calcium and silica inhibitors and further iron and manganese enhanced the critical hydrogen peroxide anion levels. Grade 5 was inferior to Grade 2. During rapid uniform corrosion, the potential of unalloyed titanium was under 200 mV (SHE) and lower than that of platinum. Over 90% of manganese and many other metals could be leached into aqueous phase for ICP-AES analysis using chelation or acid hydrolysis. An XRF method for manganese, iron and copper in pulp including little or no sample treatment was developed. Measuring temperature differences and atmospheric carbon dioxide were observed to be notable error sources of the ISE technique.

Several new potentially terdentate chelating agents based on the 8-hydroxyquinoline structure have been synthesized and characterized. Protonation constants of these ligands and formation constants of their chelates with selected metal-ions have been determined. Where possible, the chelates have been characterized by elemental analysis and other means. The results show that the ligand 2-(2'-thienyl)-8-hydroxyquinoline acts as a sterically hindering bidentate donor; the unusual relationship found between the formation constants of its bis-chelates (K1 < K2) has been explained on the basis of steric effects. The results of studies involving 4-amino-5-hydroxy-acridine and 4,5-dihydroxyacridine indicate that these ligands act as terdentate and bidentate donors, respectively. The failure of 4,5-dihydroxyacridine to act as a terdentate donor is explained in terms of chelate-ring strain. / Thesis / Doctor of Philosophy (PhD)

Este estudo teve como objetivo avaliar a capacidade de remoção da smear layer das paredes de canais radiculares instrumentados pelas soluções de soro fisiológico, EDTA a 17%, vinagre de maçã e SmearClear®, nos três níveis radiculares, associadas ou não ao ultra-som. Para tal propósito, foram utilizados 70 dentes caninos humanos superiores e inferiores extraídos os quais tiveram suas coroas removidas. O comprimento de trabalho foi determinado pela visualização da ponta de uma lima tipo K com diâmetro 10 no forame apical, subtraindo-se 1 milímetro dessa medida. Para o preparo biomecânico, instrumentou-se os dentes com o sistema rotatório ProTaper®, pela técnica coroa-ápice, até o instrumento F5, irrigando os canais com hipoclorito de sódio a 2,5% a cada troca de instrumento. Os dentes foram divididos aleatoriamente em 6 grupos de 10 dentes e 2 grupos controle de 5 dentes de acordo com o método de irrigação final a serem testados: Grupo 1 (controle) Soro fisiológico por 3 minutos sem ultra-som; Grupo 2 - (controle) Soro fisiológico por 3 minutos, sendo o primeiro minuto ativado pelo ultra-som; Grupo 3 - EDTA a 17% por 3 minutos sem ultra-som; Grupo 4 - EDTA a 17% por 3 minutos, sendo o primeiro minuto ativado pelo ultra-som; Grupo 5 - Vinagre de maçã por 3 minutos sem ultra-som; Grupo 6 - Vinagre de maçã por 3 minutos, sendo o primeiro minuto ativado pelo ultra-som; Grupo 7 - SmearClear® por 1 minuto sem ultra-som; Grupo 8 - SmearClear® por 1 minuto ativado pelo ultra-som. Em seguida, os dentes foram irrigados com hipoclorito de sódio a 2,5% e soro fisiológico e secos com cones de papel absorvente. As raízes foram seccionadas longitudinalmente e preparadas para a microscopia eletrônica de varredura com o aumento de 750 vezes. Fotomicrografias foram obtidas dos terços cervical, médio e apical e analisadas por três examinadores para a atribuição de escores para posterior análise estatística. Concluiu-se que as soluções de EDTA e SmearClear® foram efetivas na remoção da smear layer do canal radicular, com pequena vantagem numérica do EDTA, entretanto, sem diferença estatisticamente significante entre elas. O soro fisiológico apresentou resultado significativamente inferior comparado às demais soluções irrigadoras. O vinagre de maçã se mostrou ligeiramente inferior ao SmearClear® e ao EDTA, apresentando diferença estatisticamente significante ao EDTA no terço cervical. O uso do ultra-som não promoveu uma melhora significante na capacidade de limpeza de todas as soluções irrigadoras testadas. Em todos os grupos, o resultado menos favorável em relação à remoção da camada de smear layer foi observado no terço apical do canal radicular, com diferença estatisticamente significante em relação ao terço cervical. / The aim of this study was to evaluate the smear layer removal from instrumented root canal walls by saline solution, 17% EDTA, apple vinegar and SmearClear®, at three radicular levels, with or without ultrasonics. For that purpose, 70 upper and lower human canines were used, which had their crowns removed. The working length was established by visualizing the tip of a 10 K-type file at the apical foramen, by reducing 1 mm from this measurement. For preparation of root canal, the teeth were instrumented with rotatory files ProTaper®, using the crown-down technique, up to F5 instrument, irrigating with 2,5% sodium hypochlorite between each instrument change. The teeth were randomly divided into 6 groups of 10 teeth each and 2 control groups of 5 teeth according to the final irrigation protocol: Group 1 (control) Saline solution for 3 minutes without ultrasonics; Group 2 (control) Saline solution for 3 minutes, with ultrasonic activation for the first minute; Group 3 17% EDTA for 3 minutes without ultrasonics; Group 4 17% EDTA for 3 minutes, with ultrasonic activation for the first minute; Group 5 Apple vinegar for 3 minutes without ultrasonics; Group 6 Apple vinegar for 3 minutes, with ultrasonic activation for the first minute; Group 7 - SmearClear® for 1 minute without ultrasonics; Group 8 - SmearClear® for 1 minute with ultrasonic activation. Subsequently, the teeth were irrigated with 2,5% sodium hypochlorite and dried with paper points. The teeth were split open longitudinally and prepared for scanning electron microscopy at magnification of 750X. Photomicrographs were taken from coronal, middle and apical thirds and analyzed by three examiners for scores attribution for statistical analysis. It was concluded that EDTA and SmearClear® were efficient for smear layer removal from root canals, with a discrete superiority of EDTA, however, without statistical significance. The saline solution showed significant inferior results compared with the others solutions. Apple vinegar was slightly inferior to SmearClear® and EDTA, with statistical difference observed between apple vinegar and EDTA in coronal third. The ultrasonics did not enhance the cleaning ability of all the irrigating solutions tested. In all cases, the least favorable result regarding smear layer removal was observed in the apical third of the root canal, with statistically significant differences in the coronal third.

Barium sulfate scaling can cause many oilfield problems leading to loss of well productivity and well abandonment. Currently, diethylene triamine pentaacetic acid (DTPA) is used, along with synergist oxalic acid and potassium hydroxide, to remove the scale by dissolution. However, the chemical factors affecting this reaction are not known fully, leading to mixed results in terms of treatment effectiveness. This thesis investigates the effect of these factors, by analyzing the change in barite dissolution due to intrinsic factors like variations in formulation composition and extrinsic factors like presence of competing ions. The dissolution reaction is carried out, by taking the barite powder and chelant solution in a teflon round bottom flask and measuring the barite dissolved periodically, with an ICP-OES. The effect of different factors is studied by varying each factor individually and plotting the changes in solubilities. These lab tests show that solubility of barite (0.01mM in water), ideally, increases with increasing concentrations of chelating agents, even going as high as 239 mM. However experimental or field constraints lead to significant decrease in dissolution, especially at higher chelant concentrations. Thus, field tests to determine most effective chelant concentrations must precede treatment design. Lab tests also show that combination of DTPA with weaker chelating agents like ethylene diamine tetraacetic acid (EDTA), L-glutamic acid, N,N-diacetic acid (GLDA) or methyl glycine diacetic acid (MGDA) reduces barite dissolution and should be avoided during treatment design. Addition of synergists to the formulations, initially improves dissolution performance, especially for moderate chelant concentrations, but proves detrimental and hence must be avoided, over longer treatments. Finally, presence of competing ions in seawater, calcium sulfate and calcium carbonate, can significantly reduce barite dissolution and must be carefully studied for each formation-fluid system before design of treatments. Thus, this project sets a framework to identify the best chelant formulation and estimate its dissolution profile to ensure, a more informed treatment design for barite scale removal.

No description available.

Patients with acquired iron overload require chelation therapy using either Desferal or Exjade. Iron in excess may promote free radical formation in the Fenton reaction resulting in severe injuries of heart, liver and endocrine organs. Che1ators that bind ferric iron (Fe+3) in a 1:1 complex (Desferal) sequester it more efficiently than those che1ators that form 2:1 (Exjade) complexes. We initiated synthesis of new chelators derived from the tridentate chelator pyridoxal isonicotinoyl hydrazone (PIH) and its analogs. The aim of the synthesis was to generate chelators that bind iron in a 1:1 complex, which was confirmed for 8LK02, 10LK02, 11LK02 and 15LK03 by spectrophotometry. All novel chelators mobilized iron more efficiently compared to Desferal and Exjade from murine reticulocytes and human myeloid leukemia cells (K562). Additionally, aforementioned four chelators were also more efficient than PIH and were found to be less or equally toxic as Desferal and Exjade.