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In septic shock (SS), hydrogen peroxide (H2O2) and other reactive oxygen species (ROS) are released by inflammatory cells and have been implicated in tissue damage and inflammation. Recently, H2O2 has been established as an important signaling molecule and an important component of SS. The pathways involved in this process are not completely understood, but the formation of hydroperoxides (HPs), arachidonic acid (AA) metabolites and potassium (K+) channels have been implicated. In this study, we used a canine carotid ring preparation as a bioassay to determine the role of peroxyacetic acid (POX), a hydroperoxide (HP), in causing vasodilation and elucidate the subsequent pathways involved. We removed internal carotid artery segments from dogs and placed them in an organ bath. The segments were preconstricted after which we added POX to the preparation. We found that POX produced an endothelium and nitric oxide independent vasodilation in the carotid artery ring preparation. This decrease in tension could be prevented by high concentrations of K+ in the bath. This suggested that K+ channels were involved in POX’s action. Further investigation showed that the particular K+ channels implicated were the combination of small (SKCa) and intermediate conductance calcium activated K+ channels (IKCa). In addition we found that the prostaglandin H synthase (PGHS) inhibitor, indomethacin, could block POX’s mechanism of action. This finding indicates that PGHS takes part in the vasodilation caused by POX. Our results suggest that HPs that are released from inflammatory cells in sepsis could stimulate the PGHS pathway leading to prostaglandin synthesis and subsequently activating SKCa and IKCa to produce vasodilation. Inhibition of this pathway may be important component in the treatment of SS.

Conduction electron interactions in sodium and potassium studied by magnetic resonance techniques Christopher D. Latham Department of Physics, Stocker Road, University of Exeter, EX4 4QL, UK. Abstract Pure sodium consists of a mixture of body centred cubic (BCC) and hexagonal close packed (HCP) crystals at low temperatures and these two phases exhibit subtly di?erent many body e?ects despite their almost identical conduction electron densities. This thesis represents a ?rst attempt to unravel the di?erences in the values of the many body parameters which characterize the description of the two phases in terms of the Fermi liquid theory. Fresh theoretical estimates of several many body parameters are presented and shortcomings in earlier theoretical work are highlighted. It has been found that the cause of these e?ects can be attributed to the di?erent and anisotropic phonon spectra in the two crystal phases. This has little e?ect on the lowest order many body parameters; the cyclotron e?ective masss, m * c, the paramagnetic susceptibility, ?p and the Landau-Silin Fermi liquid theory spin coe?cient, B0; but the second spin coe?cient B1 is very di?erent in the two crystal phases; it also seems likely that it is highly anisotropic. This di?erence leads to the observation of splittings in the microwave transmission spin wave spectra and di?erent spin wave coalescence angles for the two phases. Experimental results of measurements on sodium are presented. The conduction electron spin resonance (CESR), observed by the 35 GHz microwave transmission spectometer at Exeter, is split into two distinct lines which can be identi?ed with the two crystal phases present. A continuum region between the lines indicates that there is some averaging of electron spins among crystal grains or there may be some sodium present in an intermediate, faulted crystal phase in the samples. These observations con?rm the earlier work of Myler (1982), who used re?ection methods, and demonstrate with exceptional clarity, the presence of the two crystal phases. Analysis of the microwave transmission spectra, in various ?eld orientations, of spin waves, Gantmakher-Kaner oscillations, and cyclotron wave signals shows no observable di?er¬ences between the two phases of the quantities m * c, ?p and B0. The estimated values, con?rmed by spin wave measurements, of B1 are -0.01 ± 0.01 in BCC sodium and -0.05 ± 0.01 in HCP sodium at 5 K. The strong possibility of anisotropy in B1 may result in ambiguity in the values obtained from spin wave measurements depending on the details of the methods used to solve for the various quantities. For the ?rst time the microwave frequency size e?ect (MFSE) has been properly identi?ed and measured for potassium metal. This is the microwave frequency version of the radio frequency size e?ect but with the additional complication that the time of ?ight of the conduction electrons across the sample is comparable with the period of the microwaves. The electron orbits are identi?ed as being the symmetrical “type II” orbits, in the terminology of size e?ect studies. Unusually high quality spectra obtained during the early test work on the 35 GHz spectrometer enabled this study to be made. August 1987

In septic shock (SS), hydrogen peroxide (H2O2) and other reactive oxygen species (ROS) are released by inflammatory cells and have been implicated in tissue damage and inflammation. Recently, H2O2 has been established as an important signaling molecule and an important component of SS. The pathways involved in this process are not completely understood, but the formation of hydroperoxides (HPs), arachidonic acid (AA) metabolites and potassium (K+) channels have been implicated. In this study, we used a canine carotid ring preparation as a bioassay to determine the role of peroxyacetic acid (POX), a hydroperoxide (HP), in causing vasodilation and elucidate the subsequent pathways involved. We removed internal carotid artery segments from dogs and placed them in an organ bath. The segments were preconstricted after which we added POX to the preparation. We found that POX produced an endothelium and nitric oxide independent vasodilation in the carotid artery ring preparation. This decrease in tension could be prevented by high concentrations of K+ in the bath. This suggested that K+ channels were involved in POX’s action. Further investigation showed that the particular K+ channels implicated were the combination of small (SKCa) and intermediate conductance calcium activated K+ channels (IKCa). In addition we found that the prostaglandin H synthase (PGHS) inhibitor, indomethacin, could block POX’s mechanism of action. This finding indicates that PGHS takes part in the vasodilation caused by POX. Our results suggest that HPs that are released from inflammatory cells in sepsis could stimulate the PGHS pathway leading to prostaglandin synthesis and subsequently activating SKCa and IKCa to produce vasodilation. Inhibition of this pathway may be important component in the treatment of SS.

A series of experiments was conducted to investigate the potential influence of pre- and post adding of catalysts to a demineralized coal char. The catalysts were chosen according to yield better catalytic activity and be inexpensive. CO2 gasification was conducted on the samples in a temperature range of 500 °C to 900 °C. The coal chosen was a high-inertinite, high-ash, Highveld bituminous coal. The catalysts chosen were sodium carbonate, potassium carbonate, and a mixture of the two catalysts. Different methods were used to investigate the factors influencing the reactivity of the demineralized coal char, and the extent of the influence from the catalysts. Proximate analysis, ultimate analysis and ash yields were conducted on the starting material to determine the change the demineralization had on the coal. Ash fusion temperatures of the samples were also obtained. The results indicated that demineralization lowered the ash content, as well as the ash fusion temperatures, but the ultimate analysis showed consistency in both sets of samples. Mass losses obtained during the thermal treatment experiments under CO2 atmosphere showed an increase in mass loss in the order of samples without addition of catalysts to the smallest amount of addition. Potassium carbonate showed the largest increase in mass loss during CO2 thermal treatment, together with the mixture of the two catalysts. Samples with pre-added catalysts also had a larger mass loss than samples with post-added catalysts. According to the XRD and QEMSCAN results, some potassium species are retained in the ash, which is confirmed by XRF results. The XRF results also showed that the amount of alkali species retained is quite large. / Thesis (M.Sc. (Chemistry))--North-West University, Potchefstroom Campus, 2011

Typescript. Thesis (Ph. D.)--University of Hawaii, 1949. Bibliography: leaves 42-47.