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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
241

Chemical Identification and Organoleptic Evaluation of Iodine and Iodinated Disinfection By-Products Associated with Treated Spacecraft Drinking Water

Dodd, Jennifer Peters 11 February 1997 (has links)
Aboard the International Space Station, potable water will likely be produced from recycled wastewater. The National Aeronautic and Space Administration (NASA) plans to use iodine as a disinfectant, and, consequently, the formation of iodinated disinfection by-products (IDBPs) requires investigation. Objectives of this research were to determine possible precursors of IDBPs, identify IDBPs formed, and apply flavor profile analysis (FPA) as a tool to evaluate water qaulity. Experiments were performed by separately reacting iodine with each of the following organic compounds: methanol, ethanol, 1-propanol, 2-propanol, 1-methoxy-2-propanol, acetone, and formaldehyde. NASA previously identified all of these compounds in wastewater sources under consideration for recycling into potable water. Experiments were performed at pH 5.5 and 8, iodine concentrations of 10 and 50 mg/L, and organic concentrations of 5 and 50 mg/L. Gas chromatography/mass spectrometry was used to identify and monitor the concentrations of organic species. Spectrophotometry was used to monitor the iodine concentration. Acetone was the only compound identified as an IDBP precursor and it reacted to produce iodoacetone and iodoform. Concentrations of iodoform from 0.34 mg/L to 8.637 mg/L were produced at conditions that included each pH level, iodine concentration, and acetone concentration. The greatest iodoform concentration was produced at pH 8 from 50 mg/L of iodine and acetone. FPA indicated that the odor threshold concentration (OTC) of iodoform was 1.5 ug/L, and the OTC of iodine was 500 ug/L. Both iodine and iodoform have medicinal odors, making it difficult to distinguish each compound when present in a mixture. / Master of Science
242

The Efficacy of Plant Residue Degradation Products on Phosphorus, Iron, Iodine, and Fluorine Bioavailability to Plants

Mackowiak, Cheryl L. 01 May 2001 (has links)
Plant and animal wastes degrade in soils to form relatively stable humified compounds, which form ion complexes that affect the bioavailability of elements in the soil solution. Hydroponic studies with wheat and rice were conducted to characterize the effect of humic acid (HA) on phosphorus (P), iron (Fe), fluorine (F), and iodine (I) bioavailability. Ferrihydrite [Fe(OH)3] precipitation was greater on root surfaces without HA or synthetic chelates. Oxides such as ferrihydrite strongly adsorb P and provide exchange sites for metals. HA reduced this precipitate and increased P and Fe uptake. Humic acid had no effect on F toxicity in rice, where solution levels above 0.5 mM F inhibited growth. Data supported the hypothesis that in moderately acidic solutions (pH< 6), F uptake is primarily as HF rather than F. Doubling solution Ca caused a 10-fold increase in root surface CaF2 precipitates, but the additional Ca did not decrease F toxicity. Calcium levels above 1 mM caused HA to flocculate over time, but the addition of F reduced flocculation by competing with HA for Ca. The majority of shoot F was apparently associated with the middle lamella, suggesting that F may bind with phosphates and pectate-Ca. Organic matter promotes aqueous iodine (I2(aq)) reduction to I-, a less toxic species. HA reduced 12( aq) toxicity by 50%. In solutions without HA, 6.5 μM h(aq) was more toxic than 30 μM I-. Humic acid had no effect on I- uptake or toxicity, where I- and IO3- were toxic to rice at 10 and 100 μM, respectively. These data were used to model element cycling through plants in a regenerative human life support system for NASA 's Advanced Life Support program, where HA, P, Fe, F, and I from plant residues and human wastes are recycled to the crop production system.
243

A Metal-Free Approach to Biaryl Compounds: Carbon-Carbon Bond Formation from Diaryliodonium Salts and Aryl Triolborates

Jayatissa, Kuruppu Lilanthi 03 April 2015 (has links)
Biaryl moieties are important structural motifs in many industries, including pharmaceutical, agrochemical, energy and technology. The development of novel and efficient methods to synthesize these carbon-carbon bonds is at the forefront of synthetic methodology. Since Ullmann’s first report of stoichiometric Cu-mediated homo-coupling of aryl halides, there has been a dramatic evolution in transition metal catalyzed biaryl cross-coupling reactions. Our work focuses on the discovery and development of an unprecedented reagent combination for metal-free cross-coupling. It is hypothesized that direct carbon-carbon bond formation occurs via a triaryl-λ3-iodane and that electrophile/nucleophile pairing is critical for success in the reaction. Proof-of-concept for this approach focused on the reaction between bromo 4-trifluoromethylphenyl (trimethoxybenzene)-λ3-iodane and potassium 3-fluorophenyltriolborate. The spectator ligand and counter ions are important parameters for both reactivity and selectivity of the aryl group transfer in this reaction. Moderate to good yields of biaryl products are obtained by this method. Experimental evidence supports the assertion of a metal-free cross-coupling reaction.
244

Bioactivity and antibacterial activity of iodine-containing calcium titanate against implant-associated infection / インプラント関連感染症に対するヨウ素含有チタン酸カルシウムの生体活性及び抗菌性

Ikeda, Norimasa 23 March 2023 (has links)
京都大学 / 新制・課程博士 / 博士(医学) / 甲第24479号 / 医博第4921号 / 新制||医||1062(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 安達 泰治, 教授 別所 和久, 教授 長尾 美紀 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM
245

The effect of the parasite Hymenolepis diminuta on iodine economy in the rat

Holmes, David Gourdon 05 August 1970 (has links)
A balance of iodine within the rats is important for the maintenance of normal thyroid function. Because of Hymenolepis d[imi]nuta's affinity for certain nutrients, it may upset norma[l] iodine balance in the rat. To determine this, tapeworm-infected and non-infected rats were given 125Iodide orally and the percent uptake of iodide by the thyroid and the amount of radioac[tiv]ity in the tapeworms was determined. The percent distribution of the radio-iodinated compounds in the thyroid, tapeworms and feces was also determined. These procedures were repeated except 125Thyroxine was administered orally. There was a decrease in percent iod[id]e uptake by thyroids of tapeworm-infected rats receiving 125I; however, there was no indication of a hypothyroid condition. Iodide, T4, and T3 were present in the worms, but not enough to account for the decrease in thyroid uptake. The more tapeworms present in the rat, the greater fecal excretion of iodide and T4. Due to this, tapeworms may cause a hypothyroid condition over a longer period of time than this study. The data indicated that T4 was metabolized by the tapeworms.
246

The effect of pregnancy and lactation on the iodine compounds in the tissues and plasma of the rat

Lyons, Harry Jay 08 August 1968 (has links)
An isotopic equilibrium method was employed, based on the chronic feeding of an 125I-labeled diet of known specific activity, to determine the distribution and quantitation of endogenously labeled iodine-containing compounds in the female rat at various periods during gestation and post-parturition. A decrease was associated with gestation in the total iodine, which was significant in all extrathyroidal tissues except the brain and muscle, and a fall in thyroxine concentration which was significant in all extrathyroidal tissues except the heart. The triiodothyronine level decreased from the control values in gestation but not as consistently. There was also a significant decrease in the total iodine and thyroxine in the plasma at this time. Concomitant with this fall in plasma iodinated compounds was a significant increase in the free thyroxine percentage. These changes were paralleled by an increased renal and fecal excretion of iodide. Total iodine, T4, T3, MIT and DIT all increased in the thyroid gland; however, these changes in the latter 3 compounds were statistically insignificant. These findings indicate that during gestation the body stores of iodinated compounds become depleted with the exception of the thyroid, which shows a greater than normal absolute concentration. A postulated increased T4 turnover rate, which could be due to a high maternal deiodination or placental thyroxine permeability and fetal deiodination, could account for the above observations. Following parturition, there was an excessive rebound of the iodinated compounds over an approximate 4 week period towards control values. In the lactating rat, these compounds remained below non-lactating levels until after weaning and then returned to the control levels rapidly. The total iodine levels in the plasma were extremely low during lactation and rose slowly as milk secretion decreased. These postpartum observations were for the most part statistically insignificant although they revealed a definite trend. These low levels of total iodine could be explained by the secretion of iodide by the mammary gland during lactation. There was an increased accumulation of total iodine, T4, T3, MIT and DIT by the thyroid gland during lactation. These data suggest an adaptation of the thyroid to the increased need for T4 to support or control the mammary glands.
247

Determination of Triacylglycerols in Edible Oils by Infusion ESI/MS and ESI/MS/MS

Asfaw, Biritawit 09 1900 (has links)
<p> Edible oils consist primarily of triacylglycerols (or TAGs), which are triesters of glycerol and fatty acids. Determination of the TAG compositions of edible oils is becoming more important, given the economic value of these oil products and the increasing incidence of adulterating high quality oils with poorer quality oils. In this study we report the development of an analytical protocol using positive ion infusion electrospray mass spectrometry (ESI/MS) in conjunction with tandem mass spectrometry which affords both identification and quantification of TAGs in edible oils samples.</p> <p> This thesis reports a simple, comprehensive and quantitative method for the analysis of TAGs in edible oils in which the optimized method involves the infusion of an oil sample in chloroform:methanol (1:1) solution (~10-15 μg/mL of oil) in the presence of 0.5 mM LiCl. A sequence of corrections were applied to the raw peak area data of the TAG molecular ions, [M+Li]+, to account for: (1) normalization of peak area data using three internal standards, (2) peak area contributions of M+2 isotopic peaks of TAGs with one more degree of unsaturation and (3) peak area contributions of LiCl adduct ions, [M+Li+LiCl]+, when applicable. The major correction involved multiplication to a given TAG peak area by the appropriate electrospray relative response factor (RRF) for that TAG. The RRFs for all TAGs containing between 48 and 63 carbons in their fatty acyl chains and between 0 and 9 degrees of unsaturation were extrapolated from experimentally determined response factors of a series of standards. The RRFs were found to decrease by 6.7% for each additional acyl chain carbon but increased by 18.6% for each double bond. Comparison of these calculated RRFs to reported RRFs for a series of TAG standards showed an excellent correlation (1.06% ± 10.20% RSD).</p> <p> The use of Li+ in TAG analysis followed from the reports by Hsu and Turk [93] and Han and Gross [18] which showed that Li+ afforded more intense MS, and particularly MS/MS, spectra than either H+ or Na+. The enhanced intensities in MS/MS spectra (determined using a triple quadrupole mass spectrometer) were critical for the identification of TAGs, including the identity of the fatty acyl group located at the sn-2 position. However, this method cannot distinguish unambiguously between isobaric TAGs. This methodology was applied to the profiling of a number of edible oils including canola, olive, sesame, grape seed, walnut and hemp seed oils. The major TAGS in these samples contained 52, 54 and 56 carbons with between 0 and 11 degrees on unsaturation in a given TAG. There were minor amounts of TAGs containing 50, 55 and 57 carbons.</p> <p> The ability of this method to determine quantitatively the number of degrees of unsaturation in an oil sample was tested by examining a series of partially hydrogenated canola oil samples kindly provided by Bunge Canada. Five oil samples derived from a single feedstock with differing numbers of degrees of unsaturation, measured as iodine values, were subjected to our analytical method. The measured iodine values were compared to iodine values calculated from the number of degrees of unsaturation obtained by our MS-based method. The slope of this correlation was 1.10 with an R^2 = 0.995. Overall, this method is much simpler and more accurate than the protocol described by Han and Gross [18]. This methodology will be applied as routine method for the analysis of TAGs in biological samples such as blood samples.</p> / Thesis / Master of Science (MSc)
248

The Fluorosulphuric Acid Solvent System: Iodine Fluorosulphates

Milne, John Buchanan 08 1900 (has links)
<p> The cryoscopic constant for fluorosulphuric acid has been determined and the nature and concentration of the impurities in the solvent have been investigated.</p> <p> The NMR and Gouy methods have been used to determine the magnetic susceptibility of solutions of iodine fluorosulphates. The NMR method has been shown to lead to spurious results.</p> <p> Cryoscopy, conductivity and UV and visual spectrophotometry have been used to elucidate the state of iodine fluorosulphates in fluorosulphuric acid. Solutions of stoichiometry corresponding to fifth-, third-, half-, uni-, tri-, and hepta-valent iodine have been investigated. The highest valence state observed was that of iodine trifluorosulphate which has been shown to be an acid in fluorosulphuric acid. Measurements on fifth- and third-valent iodine solutions indicate that I5+ and I3+ are formed. Measurements on half- and univalent iodine solutions suggest that I2+ is formed. The observed magnetic moment of this species agrees well with that required by theory, 2.0 BM.</p> / Thesis / Doctor of Philosophy (PhD)
249

STUDIES ON THE ROUTE OF SYNTHESIS OF THS THYROID HORMONE

Fawcett, David MacIndoo 10 1900 (has links)
Certain aspects of the biochemistry of the thyroid gland have been studied. The techniques of filter paper chromatography and radioautography were used to separate and identify the iodine-containing amino acids of the gland, and were modified somewhat, in order to obtain reliable results. Although a series of preliminary experiments were performed with the thyroid glands of rats in vivo, the main part of this work made use of the in vitro technique. Surviving tissue slices were incubated in the presence of the radioactive tracer, iodine131. Evidence was obtained which indicated that at least two of the amino acids found "free" in the thyroid gland were degraded by the gland to inorganic iodide. The mechanism of action of a number of thyroid gland inhibitors was investigated. It was found that all but two of the materials studied led to the formation in the tissue slices of unidentified iodine—containing materials with the simultaneous disappearence of inorganic iodide. Hence, at least a part of the goitrogenic nature of these inhibitors would appear to be due to the "removal" of iodide. It was found chat one portion of the inhibition caused by 3 - fluorotyrosine could be "reversed" in vitro with tyrosine, interesting sex variations in thyroid gland activity were observed during these experiments. / Thesis / Master of Science (MSc)
250

Immobilization of uranium and iodine by calcium phosphate minerals

Jimenez-Arroyo, Angel L. 09 August 2022 (has links) (PDF)
This dissertation is comprised of three independent but interconnected studies with the scope of further understanding uranium and iodine partitioning between apatite and fluid. The studies herein presented investigated: 1) brushite to apatite crystallization method; 2) the degree of uranium incorporation into apatite; 3) the degree of iodine incorporation into apatite. The importance of this work is assessing the role of apatite in immobilizing these elements, where uranium is a major component of spent nuclear fuel and iodine is a chemical analog of its radioactive isotope (129I). Once we understand the incorporation mechanisms, we will provide data that can be used in development of engineering barrier systems via add-on of phosphate minerals. In the first chapter we evaluate a method for the crystallization of apatite (Ca10(PO4)6(OH, F, Cl)2) using brushite (CaHPO4·2H2O) as initial material. The solutions evaluated for this transformation were NaCl, NaF, and KOH. Result yielded 100% apatite transformation from brushite when pH is 3.5 or greater. At a pH lower than 3.5, transformation yields monetite-apatite mixtures. Crystal size is reduced during the transformation from ~10 micrometer to ~1 micrometer. In the second chapter, degree of uranium uptake by apatite was evaluated. Phosphate minerals were crystallized from U-bearing NaCl solutions at 25-350°C. After experimental runs uranium concentrations in experimental solids and fluids were analyzed using Inductively Coupled Plasma – Mass Spectrometry. Additionally, characterization of the solids was performed via X-Ray Diffraction, Scanning Electron Microscopy and Electron Microprobe to confirm the brushite to apatite conversion. Results show that >90% of uranium was extracted from solution. Moreover, that the partitioning of uranium between apatite and fluid decreases with increasing temperature. In the third chapter apatite was crystallized from iodine-bearing solutions. The crystallization was evaluated at 39 and 200°C. Iodine concentration in solids were acquired via Electron Microprobe Analysis (EMPA) whereas iodine concentration in fluids were acquired via UV-Visible Spectrophotometry. Iodine concentrations in fluids yielded minimum depletion (0.1M) from initial iodine added to the system (0.1M). Partitioning data suggest that iodate (the oxidized form of iodine) is more compatible with apatite compared to iodide (the reduced state of iodine).

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