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No description available.

Preeclampsia (PE) is a maternal disorder of pregnancy, characterized by late-onset hypertension and proteinuria. It affects roughly 5-7% of all pregnancies worldwide and is a leading cause of maternal and fetal/neonatal morbidity and mortality. Cigarette smoking in pregnancy is associated with a 33% reduction in the incidence of PE, and this is dose dependent. It is hypothesized that carbon monoxide (CO), a combustion product in cigarettes, may confer cytoprotective and regulatory properties leading to the decreased incidence of PE. CO is produced endogenously by the enzyme heme oxygenase (HO), and it is thought that the manipulation of the HO/CO system in pregnancy can ameliorate or reduce the pathophysiologic signs of PE. The exposure of pregnant mice to 250 ppm CO led to an increase in each of the maternal uterine blood flow, vascularity of the placenta and vessel diameter, with a shift towards angiogenesis in the placenta tissue proteins Exposure of human placental villous explants to 250ppm CO led to a decreased production and release of the soluble vascular endothelial growth factor (VEGF) receptor -1 (sFlt-1). This molecule is increased in maternal plasma and placenta tissue of women with PE and it binds with molecules of angiogenesis, limiting their ability to interact with the endothelium. Using an AdsFlt-1 PE-like mouse model, the exposure of mice to 250ppm chronic CO prevented the hypertension, proteinuria and glomerular alterations, supporting the use of CO as a future therapeutic for women with PE. We completed a pilot study to evaluate the exposure of healthy volunteers to two, one hour inhalations of 250ppm CO. We determined the half-life of CO and we provide baseline kinetics data for males and females following CO inhalation. These data are important for future therapeutic studies in order to better establish proper dosing, concentration of CO and method of delivery. The results of this thesis contribute to the understanding of the pathophysiology of PE and provide evidence to support the use of CO as a therapeutic for this disorder. / Thesis (Ph.D, Anatomy & Cell Biology) -- Queen's University, 2014-05-01 14:38:42.584

A systematic study of formic acid electrooxidation on polycrystalline palladium is presented. The study begins with a discussion on the oxide growth process on platinum and palladium. CO electrooxidation under controlled mass transport is studied in order to elucidate the manner in which Pd interacts with CO, a proposed poisoning species in formic acid oxidation. The mechanism of formic acid oxidation is studied using various potentiodynamic techniques, including dynamic electrochemical impedance spectroscopy, which provides impedance measurements during a voltammogram. Through kinetic analysis, a model for the oxidation was developed. The impedance measurements support both the dc measurements as well as the results of the oxidation model. It was determined that CO formation was slow on Pd within the time scale of the experiments. The chief cause of surface deactivate was then determined to be the Pd surface interaction with the (bi)sulfate adsorption in the double layer region. / Graduate

A number of organometallic transformations related to proposed elementary steps in the reductive polymerization of carbon monoxide are discussed. The use of isonitrile as model ligands for carbon monoxide, with which they are isoelectronic, is proposed. Investigations show that alkyl migration to isonitrile is preferred over migration to carbon monoxide. Iminoformyl products due to hydride migration to isonitrile are not, however, observed. Syntheses of a range of cationic complexes of the type [ (η⁵-C₅H₅)M(L)₂(CNR)]⁺, [(η⁵-C₉H₇)Ru(L)₂(CNR)]⁺ and [(η⁵-C₉H₇)M(L)₂(CO)]⁺ (M = Fe, Ru; L = CO, phosphine) are described. In two cases, addition of hydride to the isonitrile cations is followed by protonation on work-up to give aminocarbene complexes. These are inert to further reduction under the conditions employed. The majority of isonitrile cations lose the isonitrile ligand to give good yields of metal hydride complexes. A mechanism involving ring-slippage of the hydrocarbon ligand is implicated. Hydride addition to η⁵-C₉H₇ complexes results, in the majority of cases, in loss of the hydrocarbon ligand from the complex and recovery of indane. Evidence for the intermediacy of metal formyl complexes in a number of hydride donation reactions is presented. These formyl complexes are formed from carbonyl hydride complexes either under moderate CO pressure or in THF solution. Hydride complexes lacking a carbonyl ligand are found to be inert. Finally, two reactions, one involving an alkyl migration reaction catalyzed by silver(I) salts, and the other involving the reduction of a metal acyl ligand to metal alkyl, are combined to demonstrate a model for carbon chain growth at a metal centre. The synthesis of an iron pentanoyl complex, followed by a decomplexation reaction, gives pentanoic acid in which all the catbon atoms are potentially directly derived from carbon monoxide. This is the first synthesis of a single homologous acid from carbon monoxide.

The development and implementation of a high resolution, direct absorption, rapidscanning infrared diode laser spectrometer incorporating a supersonic jet expansion source is described. High sensitivity is achieved by directly modulating absorption signals at frequencies in excess of 50 kHz, enabling their separation from lower frequency mechanical and diode 1/f noise. This is accomplished by rapidly scanning the diode laser across a small frequency window (~0.5-1.5cm^-1) synchronously with a pulsed supersonic expansion in a time period of 1 or 2 ms. Absorptions appear as small attenuations in the overall variation of the laser mode power across the scan window. This background profile is removed by recording the laser power without gas pulsing and subtracting. Relative frequency calibration is effected by simultaneously recording the spectrum of a reference gas and the interference fringes of an etalon. Absorption signals are recorded by means of a fast 12-bit analog-to-digital converter operating at 1 MHz. This is housed within a dedicated PC microprocessor which performs spectrometer control, data coaddition, signal processing and spectrum calibration functions. The spectrometer has been used to measure the infrared spectra of two weakly bound complexes, CO-OCS and Ne-SiH₄. The infrared absorption spectrum of CO-OCS was measured in the 5μm region of the OCS ν₃ asymmetric stretch. In addition microwave spectra of CO-OCS and two isotopomers ¹³CO-OCS and CO-OC³⁴S have been recorded using a pulsed nozzle microwave Fourier transform spectrometer. The lines have been fitted to a Watson S reduction Hamiltonian yielding rotational, quartic and (for the ground states) sextic centrifugal distortion constants. A T-shaped structure is determined and this is rationalised by a simple potential model incorporating a distributed multipole analysis of the electrostatic charge distribution, distributed dispersion contribution and a cylindrical hard-core repulsion. The infrared spectrum of Ne-SiH4 was recorded in the vicinity of the SiH₄ ν₃ triply degenerate stretching vibration centred at 2189.19 cm^-1. Ne-SiH₄ is only the second atomspherical top complex to be successfully recorded and analysed. The complex exhibits an intermolecular potential with considerably smaller anisotropy than its argon analogue Ar-SiH₄. Consequently the SiH₄ unit is almost free to rotate within the complex, resulting in novel Coriolis interaction between the angular momentum of the SiH₄ unit and that of the overall complex. Individual bands are fitted to Coriolis interaction Hamiltonians, and the band centres for all the transitions of the complex are fitted to an anisotropic intermolecular potential. Finally, applications of the spectrometer to the study of air sensitive compounds and species generated by electric discharge sources are considered.

This thesis describes the implementation of the conditional moment closure (CMC) combustion model in a numerical scheme and its application to the modelling of enclosure fires. Prediction of carbon monoxide (CO) in the upper smoke layer of enclosure fires is of primary interest because it is a common cause of death. The CO concentration cannot be easily predicted by empirical means, so a method is needed which models the chemistry of a quenched, turbulent fire plume and subsequent mixing within an enclosed space. CMC is a turbulent combustion model which has been researched for over a decade. It has provided predictions of major and minor species in jet diffusion flames. The extension to enclosure fires is a new application for which the flow is complex and temperatures are well below adiabatic conditions. Advances are made in the numerical implementation of CMC. The governing combustion equations are cast in a conserved, finite volume formulation for which boundary conditions are uniquely defined. Computational efficiency is improved through two criteria which allow the reduction in the size of the computational domain without any loss of accuracy. Modelling results are compared to experimental data for natural gas fires burning under a hood. Comparison is made in the recirculating, post-flame region of the flow where temperatures are low and reactions are quenched. Due to the spatial flux terms contained in the governing equations, CMC is able to model the situation where chemical species are produced in the high temperature fire-plume and then transported to non-reacting regions. Predictions of CO and other species are in reasonable agreement with the experimental data over a range of lean and rich hood-fire conditions. Sensitivity of results to chemistry, temperature and modelling closures is inves- tigated. Species predictions are shown to be quite different for the two detailed chemical mechanisms used. Temperature conditions within the hood effect the for- mation of species in the plume prior to quenching and subsequently species predic- tions in the post-flame region are also effected. Clipped Gaussian and ß-function probability density functions (PDFs) are used for the stochastic mixture fraction. Species predictions in the plume are sensitive to the form of the PDF but in the post-flame region, where the ß-function approaches a Gaussian form, predictions are relatively insensitive. Two models are used for the conditional scalar dissipation: a uniform model, where the conditional quantity is set equal to the unconditional scalar dissipation across all mixture fraction space; and a model which is consistent with the PDF transport equation. In the plume, predictions of minor species are sensitive to the modelling used, but in the recirculating, post-flame region species are not significantly effected.

Thesis (M.S)--Ohio University, March, 2005. / Title from PDF t.p. Includes bibliographical references (leaves 129-132)

Thesis (MSc.(Chemistry) - University of Pretoria, 2007. / Summary in English.

Thesis (Ph. D.)--Princeton University, 1922.