Hypervalent iodine (HVI) reagents are easily accessed, highly tunable, mild, selective oxidants that are less toxic and more environmentally benign compared to their heavy metal counterparts. λ3-Iodanes, which possess an iodine center bound to one aryl substituent and two heteroatom ligands, have been the subject of recent interest due to their electrophilicity and hypernucleofugality. A central focus of the Wengryniuk laboratory has been the further development and application of a class of electrostatically activated (bis)cationic nitrogen-ligated HVI (N-HVI) reagents. N-HVIs feature datively bound heterocyclic ligands which results in dramatically enhanced electrophilicity and redox potentials. Despite being a highly tunable platform for reagent development, N-HVIs remain a relatively underexplored class of λ3-iodanes. This dissertation focuses on demonstrating N-HVI’s synthetic potential and developing novel variants to enhance their synthetic utility. Chapter 1 of this dissertation serves as a general background and introduction to nitrogen-ligated HVI reagents. Chapter 2 outlines our efforts in N-HVI library expansion, novel syntheses, and characterization. With a library of 33 novel N-HVIs in hand, ligand effects on N-HVI reactivity were analyzed via qualitative and quantitative methods. Chapter 3 describes our first synthetic application of N-HVIs in the development of novel oxidative rearrangements of simple and complex cyclic alcohols. This chapter describes the chemoselective ring expansion of 2° and 3° cyclic alcohols accessing medium-sized cyclic acetal products in good to excellent yields with applicability to Complexity-to-Diversity (CTD) efforts. Chapter 4 demonstrates our initial efforts toward the development of another synthetic method where the functionalized N-heterocyclic ligands of the N-HVIs can be regioselectivity incorporated into a molecule following N-HVI activation of an olefin. The pyridinium lactone salts formed from olefinic acids were isolated in excellent yields via simple trituration, supplying a synthetically useful functional handle that was easily derivatized via known methods. These four chapters summarize the current state of the research with nitrogen-ligated HVI salts, expand upon our initial publications to highlight the development of novel heterocyclic syntheses, and provide a useful guide to further explore the reactivity of these tunable reagents. / Chemistry

Hypothyroidism is a common endocrine disorder affecting women of reproductive age. On a global level, iodine deficiency is still the most common cause of hypothyroidism. Also genetic variations, in particular SNP rs4704397 in the PDE8B gene, are responsible for a significant proportion of TSH variations.  Untreated hypothyroidism has significant adverse effects on pregnancy and fetal outcome. Most international guidelines suggest targeted thyroid testing in pregnant women with risk factors for thyroid disturbances. In a case-control study, an association between homozygous A/A as well as homozygous G/G carriers of SNP rs 4704397 in PDE8B and recurrent miscarriage was found. The explanation for this association is unknown. In a nationwide survey, all guidelines for thyroid testing and management of hypothyroidism during pregnancy in Sweden were collected and compared with international guidelines. The local guidelines were variable and poorly compliant with the international guidelines. In a follow-up in one district, 5,254 pregnant women were included for subsequent review of their medical reports. We found a targeted thyroid testing rate of 20.1% in clinical practice, with an overall frequency of women with trimester-specific elevated TSH of 18.5%. More disturbingly, half of the women who were on levothyroxine treatment at the time of conception had an elevated TSH level at thyroid testing. In a subsequent cohort study of the 5,254 women, we found the prevalence of trimester-specific elevated TSH and overt hypothyroidism to be equal in targeted thyroid tested and untested women. In a cross-sectional study, a median urinary iodine concentration (UIC) of 98 μg/l was found in the study population. According to WHO/UNICEF/IGN criteria, the population-based median UIC during pregnancy should be 150-249 μg/l. In conclusion, genetic variations may contribute to adverse pregnancy outcomes. In clinical practice, thyroid testing and the management of hypothyroidism during pregnancy is unsatisfactory, regarding the whole chain from development of local guidelines to their implementation and to targeted thyroid testing. Moreover, our results indicate insufficient iodine status in the pregnant population of Sweden.

No description available.

Call number: LD2668 .T4 1979 L48 / Master of Science

The reaction between various forms of manganese dioxide and halide ions has been investigated. Analytical techniques for the study of this heterogeneous liquid-solid reaction have been developed. The appearance of the reaction products, I₂ and Mn²⁺, was monitored in the aqueous phase of the reaction mixture. I₂ was monitored using amperometry. Mn²⁺ was monitored by a novel application of flow injection analysis. A molecular mechanism was postulated which accounts for the complex pH dependence of the reaction and the inhibition of the reaction under conditions of lower hydrogen ion concentration. The potential of the manganese dioxide-iodide reaction for the metallurgical processing of ferromanganese nodules has been demonstrated. Studies show that there is a preferential dissolution of the manganese portion of the nodules by the action of iodide in acidic conditions. The use of deconvolution techniques for obtaining information from overlapping flow injection analysis peaks has been shown to be feasible. Deconvolution techniques allow an increase in the sampling rates which will broaden the application of flow injection analysis in kinetic studies.

The development of a Doppler Global Veocimetry (DGV) system is described. An argon ion laser has been modified to suit the requirements of DGV. An etalon with high precision tilting control has been mounted in the laser cavity. The backward mirror of the laser cavity has been mounted on a piezotranslator for controlling the laser cavity length. Two iodine cells have been designed and manufactured: one with a bead of iodine in the cell volume, the other with a limited amount of iodine. The iodine absorption line of both cells has been calibrated with good repeatibility. The laser has been stabilized in frequency, so that operations during a measurement session in the lab are simplified. The capabilities of DGV measurements have been tested in two jets, at low and at high speeds. Velocity fluctuations of the jet could be followed, in spite of the highly noisy signals. The first steps towards three velocity component measurements with a single camera in a difficult environment such as the geometry of a turbomchinery cascade have been made. Imaging two views of a target on the same camera sensor is discussed, along with the spatial and luminosity calibration required.

A pulsed-beam fourier transform microwave spectrometer was used to measure the rotational spectra of iodine heptafluoride, iodine pentafluoride, and the weakly bound complex, HCl...NNO. For IF7, only five rotational transitions were observed, and no resolvable hyperfine structure was detected. Based on this data, the A, B, and C rotational constants were determined to be 1746(3) MHz, 1732.0(8) MHz, and 1553.0(2) MHz, respectively. The existence of a pure rotational spectrum confirms that this molecule undergoes polar distortions. Twenty-two hyperfine components of the IF5 spectrum were recorded. The B rotational constant for this molecule was determined to be 2727.421(3) MHz, and the quadrupole coupling constant was found to be 1069.35(13) MHz. Though the work is still in progress on HCl...NNO, nine transitions have been recorded. In addition, five transitions have been recorded for an apparent trimer species composed of HCl, NNO, and an as yet unidentified third species.

No description available.

The main aim of this thesis was to evaluate the current state of iodine levels in horses from selected farms in South Bohemia. Out of the sample group, no animal with iodine deficiency was detected. Additional objective of this thesis was to assess whether selected horse owners supplement their horses with iodine and what form of supplementation they choose.

Produtos de fracionamento da Farinha de Soja Desengordurada e Autoclavada foram administrados a ratos para avaliar ação na tireóide, em ensaios desde 7 até 84 dias de duração. Frações de baixo peso molecular, solúveis em água e acetona, quando avaliadas em ensaios agudos, de 24hs ou \"in vitro\", provocaram uma diminuição na captação de I-131. Porém, quando avaliados em rações, em experiências de até 84 dias de duração, mesmo em condições de restrição de iodo, não apresentaram efeito significativo. Por outro lado, identificou-se um fator, associado às frações de alto peso molecular, que induz, já a partir de 14 dias, quando administrado em rações com restrição em iodo, um aumento no peso da tireóide, redução na captação de I131, alterações na Síntese dos hormônios e seus precursores a nível glandular. Em ensaios mais longos (84 dias), provoca uma diminuição de T4 sérico e uma rarefação bastante significativa no colóide do folículo glandular. Por sua vez, a hidrólise de uma das frações de alto peso molecular, por pepsina e pancreatina, não é capaz de inativar a ação desse fator. O seu mecanismo de ação parece ser semelhante ao de substâncias que agem a nível de captação de iodo pela tireóide. / Defatted autoclaved soybean flour presented a water/acetone soluble fraction which is able to depress I-131uptake by rat thyroids tested in 24hs \"in vivo\" or in 3hs \"in vitro\" assays. When this fraction was given to rats in ration with either normal or deficient iodine content for periods from 7 to 84 days no significant action was detected. On the other hand a factor associated to the high molecular weight protein fraction was identified. The factor is active in rats starting from 14 days after ingestion, in rations with low iodine content producing: increase in thyroid weight, lowering of I-131 uptake, alteration on MIT/DIT, T3/T4 ratios and after 84 days of administration a significant reduction of serum T4 and a large decrease of the colloid content of follicle. Hydrolysis by pepsin or pancreatin does not eliminate the observed action. The mechanism of action of this factor seems to the related to a blockage of the iodine uptake.