During alcoholic fermentation Saccharomyces cerevisiae metabolizes L-arginine to ornithine and urea. S. cerevisiae can metabolize urea through the action of urea amidolyase, encoded by the DUR1,2 gene; however, DUR1,2 is subject to nitrogen catabolite repression (NCR) in the presence of high quality nitrogen sources during fermentation. Being cytotoxic at high concentrations, urea is exported into wine where it spontaneously reacts with ethanol, and forms the carcinogen ethyl carbamate (EC). Urea degrading yeast strains were created by integrating a linear cassette containing the DUR1,2 gene under the control of the S. cerevisiae PGK1 promoter and terminator signals into the URA3 locus of the Sake yeast strains K7 and K9. The ‘self-cloned’ strains K7EC- and K9EC- produced Sake wine with 68% less EC. The Sake strains K7EC- and K9EC- did not efficiently reduce EC in Chardonnay wine due to the evolutionary adaptation of said strains to the unique nutrients of rice mash; therefore, the functionality of engineered yeasts must be tested in their niche environments as to correctly characterize new strains. S. cerevisiae possesses an NCR controlled high affinity urea permease (DUR3). Urea importing yeast strains were created by integrating a linear cassette containing the DUR3 gene under the control of the PGK1 promoter and terminator signals into the TRP1 locus of the yeast strains K7 (Sake) and 522 (wine). In Chardonnay wine, the urea importing strains K7D3 and 522D3 reduced EC by 7% and 81%, respectively; reduction by these strains was equal to reduction by the urea degrading strains K7EC- and 522EC-. In Sake wine, the urea degrading strains K7EC- and 522EC- reduced EC by 87% and 84% respectively, while the urea importing strains K7D3 and 522D3 were significantly less capable of reducing EC (15% and 12% respectively). In Chardonnay and Sake wine, engineered strains that constitutively co-expressed DUR1,2 and DUR3 did not reduce EC more effectively than strains in which either gene was expressed solely. Uptake of 14C-urea under non-inducing conditions was enhanced in urea importing strains; parental strains failed to incorporate any 14C-urea thus confirming the functionality of the urea permease derived from the integrated DUR3 cassette. / Medicine, Faculty of / Medical Genetics, Department of / Graduate

In an attempt to determine mechanisms of certain aspects of ethanol- induced fetal damage, I have established a mouse model of the fetal alcohol syndrome based on the work of Chernoff (1977), using inbred C3H mice. Ethanol or its metabolite, acetaldehyde, was administered to female mice prior to and throughout gestation. Ethanol in doses of 6%, 10% and 20% ethanol derived calories and acetaldehyde 3. 9 mg and 11. 8 mg were administered daily in a nutritionally balanced liquid diet. An acute dose study was also undertaken, in which pregnant C3H mice were given. "binge" doses of 1ml of a 7. 35% solution of ethanol, twice daily through an orogastric tube, on days one and eight or four and twelve of gestation. The mice were sacrificed on day eighteen of gestation and the fetuses weighed and examined macroscopically. Some were sectioned using Wilson's method of free-hand razor blade sectioning (Barrow and Taylor, 1969), and the skeletons of the others were examined using a modified Dawson's method of skeletal preparation (Richmond and Bennett, 1938). A separate in vitro model based on the work of New (1967) was established, in which embryos of eight or nine days' gestation were explanted with visceral yolk sac intact from normal C3H mice. They were cultured for twenty-eight hours in rat serum containing various concentrations of ethanol or acetaldehyde (ethanol 1500, 3000 and 6000mg/l and acetaldehyde 7.4, 19. 7 and 39.4mg/l). During the last four hours of the culture period the embryos were labelled with one microcurie of tritiated thymidine (specific activity 5curies/mmol). At the end of the culture period the embryos were assessed morphologically, and then prepared for liquid-scintillation counting to determine DNA synthesis by measuring tritiated thymidine uptake. Small numbers of embryos from each group were used for autoradiographic studies in an attempt to quantitate the uptake of label in the various parts of the embryo. I found that ethanol given in chronic dosage in vivo was embryotoxic in all three doses studied. There was no evidence of ma tern al toxicity other than hyperactivity at the highest dose used and maternal jaundice in a small number of the 10% EDC and 20% EDC mice. Acetaldehyde given in chronic dosage in vivo produced no toxic effects on mothers or fetuses, other than a reduction in placental weights. Acute "binge" ethanol dosage of mothers on days one and eight or four and twelve of gestation did not appear to have any adverse effects on mothers or fetuses, apart from changes in placental weights. These findings should be viewed with caution, as the in vitro studies did not produce a corresponding result. In the latter study there was a marked time-related response, particularly for acetaldehyde. Ethanol given in vitro produced little evidence of toxicity except at dose levels which in the corresponding in vivo situation were extremely toxic to the mothers. Acetaldehyde, given in vitro in minute fractions of the harmless doses given to mothers in vivo, proved to be highly toxic to 8-day embryos and relatively non-toxic to 9-day embryos. This difference in sensitivity indicates that there must be some protective factor intervening between eight and ten days gestation - possibly the developing placenta may have a role here. From these findings I would suggest that acetaldehyde is a true teratogen, and the abnormalities produced in the chronic ethanol in vivo study were probably largely due to the action of acetaldehyde.

Dormant bermudagrass (Cynodon dactylon) fairways become matted down and thinned out from winter traffic. This appears to be more of a problem on the coarser textured, winter hardy, improved varieties (e.g., 'Midiron' and 'Vamont') typically used in the colder regions of the upper transition zone. Winter overseeding with cool-season species can improve dormant bermudagrass winter and spring quality. However, bermudagrass persistence can decline in golf course fairways overseeded with ryegrasses (Lolium sp.) for winter quality if ryegrasses persist due to cool spring temperatures, use of persistent ryegrass varieties, and management practices that favor ryegrasses over bermudagrass. Winter overseeding practices that facilitate a reliable transition from overseeded species to bermudagrass would enable transition zone golf courses to overseed bermudagrass fairways for winter-spring quality while allowing the bermudagrass turf to persist without excessive competition from cool-season overseeded species. Studies were conducted to determine the effects of perennial ryegrass (L. perenne) and annual ryegrass (L. multiflorum) seeding rates on winter-spring quality and subsequent transition to bermudagrass in two transition zone locations. Studies were also conducted to determine the potential influence trinexapac-ethyl (TE), a plant growth regulator used by many professional turfgrass managers to suppress foliar growth, has on encouraging overseeded species to transition to bermudagrass. These studies demonstrated that higher overseeding rates (448 and 896 kg ha-1) can provide greater winter-spring quality but do not enhance transition to bermudagrass over lower overseeding rates (224 kg ha-1). This was especially evident in cooler transition zone climate, where higher overseeding rates delayed transition to bermudagrass. Annual ryegrass transitioned to bermudagrass better than perennial ryegrass, but the overseeded winter-spring quality of annual ryegrass was unacceptable. Perennial ryegrass varieties differed in transition. Some perennial ryegrass varieties were too persistent to fully transition to bermudagrass even with the onset of summer temperatures. Intermediate ryegrasses (L. multiflorum x L. perenne) appeared to be promising alternatives to overseeding perennial ryegrass in areas of the transition zone where summer reliance on bermudagrass turf is strongly preferred. Trinexapac-ethyl, when applied to overseeded perennial ryegrasses, did not enhance overseeded ryegrass transition to bermudagrass. Spring TE applications to overseeded perennial ryegrasses were found to reduce or delay their transition to bermudagrass. / Master of Science

Mit der präparativen Synthese der Tetraorganozinn(IV)-verbindung 4-[2-(Triphenylstannyl)ethylpyridin, Ph3Sn-(CH2)2-4Py, ausgehend von der Lewis-Säure Triphenylzinnchlorid, Ph3SnCl, konnte eine Blockade der reaktiven Lewis-Säure in Form des Zinnatoms dargestellt werden, in dem vier organische Liganden das zentrale Zinnatom einerseits topologisch und andererseits durch die weitreichende Stabilität von Zinn-Kohlenstoff-Bindungen abschirmen. Die Funktionalität konnte dadurch auf das funktionelle Stickstoffatom mit seiner Lewis-Base-Funktion, was neben der strukturellen Charakterisierung von 4-[2-(Triphenylstannyl)ethylpyridin durch eine Vielzahl an weiteren Verbindungen gezeigt werden konnte, verschoben werden. Synthesemöglichkeiten zu Komplexen von 4-[2-(Triphenylstannyl)ethylpyridin mit Übergangsmetalldichloriden, Triorganozinnhalogeniden und Diorganozinndihalogeniden konnten ebenso wie Salzbildungen zu 4-[2-(Triphenylstannyl)ethylpyridinium-halogeniden gezeigt werden. Verschiedentliche Umsetzungen konnten die Neigung der Bildung von Kokristallisaten zusammen mit protonierten Formen von 4-[2-(Triphenylstannyl)ethylpyridin und weiteren Stoffklassen zeigen. Durch Umsatz mit meta-Chlorperbenzoesäure wurde das Oxidationsprodukt 4-[2-(Triphenylstannyl)ethylpyridin-N-oxid dargestellt. Die Reaktivierung der eigentlichen Lewis-Säure-Funktion des Zinnatoms wurde über Synthesen mit Halogenwasserstoffsäuren im Verhältnis über 1 : 2 realisiert. Die Arbeit thematisert neben den Studien zur Synthese und chemischen Funktionalität ausführlich relevante Strukturaspekte der über Röntendiffraktometrie gewonnenen Strukturparameter der dargestellten Verbindungen.

1-Decene is a valuable product in linear alpha olefins plants that is contaminated with 2-EHA (2-ethyl hexyl amine). Using organic solvent nanofiltration membranes for this separation is quite challengeable. A membrane has to be a chemically stable in this environment with reasonable and stable separation factor. This paper shows that Teflon AF 2400 and cellulose acetate produced interesting results in 1-decene/2-EHA separation. The separation factor of Teflon AF 2400 is 3 with a stable permeance of 1.1x10-2 L/(m2·h·bar). Likewise, cellulose acetate gave 2-EHA/1-decene separation factor of 2 with a lower permeance of 3.67x10-3 L/(m2·h·bar). A series of hydrophilic membranes were tested but they did not give any separation due to high degree of swelling of 2-EHA with these polymers. The large swelling causes the membrane to lose its diffusivity selectivity because of an increase in the polymer's chain mobility.

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The following were examined by taking advantage of TRDP using two-phase separation mixed solution: protein separation by the TRDC with the ternary mixed solution of water–acetonitrile–ethyl acetate, optical isomers separation by the TRDC with the ternary solution containing cyclodextrin as a chiral recognition molecule, development of the TRDC with a water–acetonitrile mixed solution containing sodium chloride as a two-phase separation mixed solution instead of the ternary solution, and introduction of the principle of the TRDC to a commercial HPLC system. Furthermore, the peroxioxalate CL detection was for the first time examined by using the ternary mixed solution. The investigation of the TRDP and TRDC, as well as the ternary mixed solution of water–acetonitrile–ethyl acetate, are interesting in view of not only analytical chemistry but also chemical engineering, and physical chemistry. / 博士(工学) / Doctor of Philosophy in Engineering / 同志社大学 / Doshisha University

Submitted in fulfilment of the requirements for the degree of Masters of Science in Medicine in the Health Science Faculty University of Witwatersrand Johannesburg 10 April 2019 / The Forensic Chemistry Laboratories in South Africa have, between the year 2014 and 2017, endured a lot of media scrutiny surrounding a backlog of specimens for blood alcohol and toxicology analyses and the poor environmental and storage conditions in which these specimens are kept. Many studies have been performed on the stability of alcohol in blood, since environments are not standard, to gain a better understanding on whether the backlog issues significantly impact on the integrity of the blood-alcohol concentration (BAC) results by evaluation of conditions, especially variables such as temperature and headspace. The aim of this study was therefore, to assess the stability of ethanol concentrations in post-mortem blood specimens by evaluating temperature (room and refrigerator) and headspace (4mL and 8mL) variables at 3 months and 6 months respectively. Blood from 119 decedents was collected, analysed and subjected to the varied volumes and storage conditions. Blood alcohol was determined and quantified using a G1888 Headspace Auto sampler (Agilent Technologies®) coupled to a 6890N Agilent® Gas Chromatography instrument utilising a Flame Ionization Detector on an Agilent HP-Innowax® column. A general decrease in alcohol concentration was observed over a storage period of 6 months regardless of the storage temperature, whilst headspace was found to have no significant effect on the BAC results. It is, therefore, important that Forensic Pathologists, investigators and scientists are aware of factors such as temperature and headspace and consider them when interpreting blood alcohol results from a post-mortem environment. / E.K. 2019

No description available.

No description available.