Journal and Proceedings of The Royal Society of New South Wales
ABSTRACTS OF STUDENT THESES IN VOLS 118-132: Part 2 of 5 (VOLS 123-126)
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CONTENTS
(in chronological order of publication)
| 1985-1990 [v118 pts 1-2 to v122 pts 3-4] | |
| Go to Theses Abstracts Archive Part 1 | |
| 1990 [v123 pts 1-2] | |
| Lyons, Stephen D. | Inhibition of de Novo Nucelotide Biosynthesis in Mouse L1210 Leukaemia |
| 1991 [v123 pts 3-4][for 1990] | |
| Fenton, Ronald R. | Stereochemical Studies on Metal Chelates of Novel Asymmetric Ligands |
| Minty Jun, E.J. | Late Pleistocene Geocryology of the Bogong High Plains |
| 1991 [v124 pts 1-4] | |
| [No Abstracts of Theses were published in this issue] | |
| 1992 [v125 pts 1-2] | |
| Coenraads, Robert R. | Alluvial Sapphire and Diamond Deposits of the New England Gem Fields, New South Wales, Australia |
| 1992 [v125 pts 3-4] | |
| [No Abstracts of Theses were published in this issue] | |
| 1993 [v126 pts 1-2] | |
| Gatei, Magtouf H. | Some Aspects of the Pathogenicity and Immunity of Bovine Leukemia virus Infection in Cattle and Sheep |
| He, Fuxiang | Provenance, Diagenesis and Reservoir Characteristics of Sandstones of the Great Australian Basin Succession in NSW, Australia |
| Oudshoorn, Michael John | Atlantis: A Tool for Language Definition and Interpreter Synthesis |
| Yoo, E.K. | Stratigraphic and Coal Seam Correlations of the Illawarra Coal Measures in the Ulan and Bylong Areas, Western Coalfield, Sydney Basin, New South Wales |
| Xu, Arron S.L. | 19F NMR of Erythrocytes: "Split Peak" Phenemenon, Membrane Potential and Membrane Transport |
| 1993 [v126 pts 3-4] | |
| Langford, Steven J. | Porphyrin-Based Building Blocks |
| Bishop, Mark A. | Craterform Origin Derived by Quantitative Geomorphology |
| Cheras, P.A. | The Role of Thrombosis in Ischaemic Necrosis of Bone (NB) and Primary Osteo-Arthritis (OA) |
| Mohr, Philip B. | Reconciling the Roles of Status and Behaviour in Group Influence: Towards a Status-Confirmation |
| 1994-1995 [v127 pts 1-2 to v128 pts 3-4] | |
| Go to Theses Abstracts Archive Part 3 | |
| 1996-1997 [v129 pts 1-2 to v130 pts 3-4] | |
| Go to Theses Abstracts Archive Part 4 | |
| 1998-1999 [v131 pts 1-2 to v132 pts 3-4] | |
| Go to Theses Abstracts Archive Part 5 | |
Doctoral Thesis Abstract: Inhibition of de Novo Nucelotide Biosynthesis in Mouse L1210 Leukaemia
Stephen D. Lyons
A new high pressure liquid chromatographic procedure has been developed for the analysis of drug-induced effects on nuceotide biosynthesis in cultured mammalian cells. More than 40 nucleotides, nucleotide precursors and related compounds (including phosphorylated drug derivatives) can be identified and quantified from their elution time, wavelength of maximum absorbance and pattern of radiolabel incorporation of [14C]bicarbonate (for pyrimidines and purines) and [14C]formate (for purines) (1-3) The major sites of cyclotoxicity of a number of anti-metabolites currently in clinical use, or at the investigational stage, have been determined in leukaemia cells growing in culture. These conclusions should enable more effective chemotherapy with these agents, either singly or in combination with other anti-cancer drugs. Some of this data has appeared in a review (4)
The monophosphate derivative of pyrazofurin, a nucleoside-analogue antibiotic, is a potent inhibitor of orotidine 5'-monophosphate decarboxylase of pyrimidine biosynthesis and has been postulated to inhibit 5-aminoimdidazole-4-carboxymadie ribotide (AICAR)transformylase of purine biosynthesis. We found that pyroazofurin inhibits only the former enzyme and, indeed, stimulates purine biosynthesis in growing leukaemia cells (5).
The drugs, brequinar and ciprofloxacin, have been inplicated in the inhibition of early reactions of pyrimidine biosynthesis. Brequinar was determined to act in an analogous fashion to dichloroallyl lawsone (1), via potent inhibition of the ubiquinone-dependent enzyme dihydroorotate dehydrogenase. No evidence was obtained for the inhibition of any enzyme of pyrimidine biosynthesis by ciprofloxacin, although this antibiotic probably inhibits electron transport or oxidative phosphorylation in leukaemia cells (3).
The glutamine analogues, acivicin, azaserine and DON, are potent inhibitors of many purified or semi-purified amido-transferases. The major sites of inhibition of nucleotide biosynthesis were determined to be different for each antagonist in growing cells although all three antagonists inhibit N-formyl-glycineamidine ribotide (FGAM) synthetase and induce massive accumulations of the substrate for this reaction, N-formyl-glycineamide ribotide (FGAR), and its di- and triphosphate derivatives. Interference with nucleic acid synthesis by these "unnatural" metabolites may be another mechanism of cytoxicity of glutamine antagonists (6).
The mechanism of cytotoxicity induced by methotrexate and other classical and non-glutamate containing anti-folates is still to be elucidated. Both classes of anti-folates inhibit purine biosynthesis at AICAR transformylase (reaction 9) more potently than glycineamide ribotide (GAR) transformylase (reaction 3). However, in subsequent studies we concluded that polyglutamate derivatives of dihydrofolate, accumulated due to potent inhibition of purine biosynthesis primarily at an initial reaction of the pathway prior to both transformylase reactions (7).
Fluoroorotate is structurally similar to the antgi-cancer drug, fluorouracil,and was used as a model compound for the development of active pro-drug derivatives of inhibitors of dihydroorotase designed and synthesized in this laboratory (e.g.,thiodihydroorotate; (8)). Non-polar fluoroorotate esters were the most cycotoxic with the benzyl pro-drug having an IC50 value of 0.26μM compared with the free acid IC50 value of 4.9μM. The benzyl ester of thiodihydroorotate has been found to have its cytotoxicity similarly enhanced relative to the free acid (9).
A phenomenon called "complementary stimulation" has been described for cells exposed to an anti-metabolite where either pyrimidine of purine biosynthesis is inhibited and the uninhibited pathway is stimulated. Potent inhibitors of pyrimidine biosynthesis (pyrazofurin, dichloroallyl lawsone and brequinar) induce a surge through the purine pathway resulting in an elevation of purine nucleotides and precursors above pre-drug levels. Purine antagonists (methotrexate and DON) have an analogous effect on pyrimidine biosynthesis. This phenomen illustrates the interdependence of the pathways of nucleotide biosynthesis via their common intermediates, 5-phosphoribosyl 1-pyrophosphate (P-Rib-PP) and L-glutamine. References
Ronald R. Fenton This work reports the synthesis and characterisation of high resolution 1NMR, chiroptical and X-ray crystallographic techniques of a series of new chiral multidentate ligands and their representative cis-octohedral and square-planar metal complexes. The design of the ligands was such that they all contain sterically demanding terminal pyridyl groups and each coordinating sedgment of the multidentate is capable of forming a five-membered chelate ring.
The purpose of synthesising these ligands was two-fold. Firstly to examine the effects that bulky substituents at different sites of the ligands have on the topology adopted and the consequent steroselectivity achieved on coordination to metal ions. Secomndly these metal complexes then were used to investigate the intermolecular disrriminations arising from their use as chiral templates in the synthesis and resolution of α-amino acids. The ligand picchxnMe2 (N,N'-dimethyl-N,N'-di(2-picolyl)diaminocyclohexane, picpnMe2 (N,N'-dimethyl-3-methyl-1,6-di(2'-pyridyl)2,5-diazahexane) and picpyrrMe (N,N'-di(2-picolyl)-N'-methyl-2-aminomethylpyrrolidine) coordinate stereospecifically to cobalt(III) forming cis-octahedral complexes. The R or R,R' forms of the ligands always adopt Δ-α topoology while their enantinomers produce Λ-α forms, with these geometries being retained during a variety of substitution reactions. When the ternary complex Λ-α=[Co(R,R'-pistien)Cl2]+ (picstien = 3,4-diphenyl-1,6-di(2'-pyridyl)-2,5-diazahexane) is reacted with 2-amino-2-methylpropandiocacinato anion (AMMA2-) the chloride ions are dsiplaced by the bidentate AMMA2- which sterospecifically adopts the β1 and stereoselectively the pro-S configurations. Decarboxylation of this complex in warm acidic solution produces a mixture comprising 93 ± 3% Λ-β1-[Co(R,R-picstien)(R-ala)]2+ and 7 ± 3% Λ-β1 -[Co(R,R-picstien)(S-ala)]2+, as shown by 1H NMR experiments. The chiral environment imposed on the prochiral AMMA2- fragment by the coordinated R,R,-picstien ligand thus allows a stereoselective asymmetyric syhthesis of R-alinine in high enatiomeric excess Thge crystal structure of decarboxylation intermediate species Λ-β1-[Co(R,R-picstien)-(AMMA)]Clo4.2H2) complex was determined. Crystal data: C30H35N5O10ClCo is orthorhombic, space group P212121 with a = 9.598(2), b = 11.964(2), c = 26.477(3) &Angst;, Z = 4. The structure was refined by block-matrix least-squares methods to R = 0.019 for 2622 non-zero diffractometer data. For the symmetrical cis-α picchxnMe2 cobalt(III) complexes no evidence of any chiral induction was found in their use for the synthesis of α-aniline. However, these complexes were found to be successful in the resolution of the more sterically demanding α-amino acid proline. Coordination of a series of chiral and mesomeric bis-picolylamine ligands to square-planar palladium(II) was used to demonstrate the steric effects present in these complexes. Alkyl substituents were placed on the central diaminoethane link, at the secondary nitrogen atoms anfd at the 6-positions of the terminal pyridyl rings of the tetradentates. The chiral forms of these ligands with two vicinal substituents on their central links show stereospecific coordination behaviour irrespective of the presence of the methyl substituent on the 6-position of the terminal pyridyl rings. However, with protons at the 6-position and methyl groups on the backbone nitrogen atoms, or with only one asymmetric substituent on the central diamine link, , they are stereoselective. The meso forms of the ligands produce two conformational isomers on coordination, but with methyl sustituents at eh 6-position only one isomer form is formed. Two optically active bis-picolylinamide ligands, bpatienH2 (N,N'-bis(2'-pyridine-carboxamide)-1,2-diphenylethane), and their bivalent copper, nickel and palladium depronated complexes were synthesised. The square-planar nickel(II) and palladium(II) complexes adopt rare molecular structures, having their phenyl substituents occupying axial position(s) onthe central chelate rings. E.J. Minty Jun. The Bogong High Plains comprises fragmented, elevated surfaces (at 1600m to
1986m elevation), of low to moderate relief and contains relic cryogenic
features. Conclusive evidence of glacial features has not been observed on the
Bogong High Plains. This thesis has examined the distribution of the cryogenic features and
their lateral equivalents in the adjoining valleys of the Mitta Mitta and
Kiewa Rivers, with a view to defining processes active in the late Pleistocene.
The stratigraphy of thirty-six sites in these valleys reveals relic alluvial
fans on the valley sides and in the piedmont zone up to 1200m ASL. These relic
alluvial fans correlate with relic cryogenic features at higher altitudes. Three areas at Mr Nelse, Basalt Hill and Pretty Valley were targeted for
detailed description and analysis of surficial geology. The cryogenic features
defined from this study have been compared to those described on other studies
of Alpine areas in south-eastern Australia. The suite of relic cryogenic features mapped and described in detail
includes: cryoplanation surfaces, nivation hollows, blockfields, block glacis,
block slopes, block streams and talus. The differentiation of these block
deposits is based on distribution patterns controlled by slope angle, aspect,
prevailing wind direction, altitude range and availability of moisture, as well
as the availabiity of appropriately jointed bedrock, such as basalt and
granodiorite. There would appear to be an associated suite of transport
mechanisms ranging from low angle (< 2°) transport of cobbles and blocks by
frost creep and possibly gelifluction to high angle (>30°) rolling and
sliding downslope. Surface features, including thermokarst on some of the block accumulations
suggest considerable interstitial ice during the period of accumulation. The relic status of block accumulations is evident from encroaching
vegetation, insitu weathering and adjoining stratigraphy. Frost wedging and
associated frost creep appear dormant now and the shallow depth of seasonal
frost prohibits gelifluction within the present climate. The development of
blockstreams and blockslopes which bear thermokarst pitting would appear to have
required deep seasonal freezing and accretion of interstitial ice as lenses or
blisters near the water table beneath the block layer. The model for the accumulation of these block deposits presented in this
thesis requires deep seasonal freezing without the need for permafrost
conditions. Mean annual temperatures of about 0°C would have been necessary
to preserve interstitial ice down to about 1300m ASL, during the period of
accumulation. Relic nivation hollows at 1500m to 1600m ASL suggest a minimum 5°C
decrease in average temperatures during the last cold climate phase. The
lateral equivalents of these block deposits in the adjoining valleys (relic
alluvial fans) suggest semi-arid conditions with at least 50% less
precipitation than present. Transistion of the above relic cryogenic features towards rock glaciers is
suggested in the Kosciusko area, which is generally 300m higher than the Bogong
High Plains. Increased snow accumulation and increased depth of freezing in the
Kosciusko area may account for this transistion. Robert R. Coenraads The CentraL Volcanic Province in northern New South Wales, also known as the New England Gem Field is one of Australia's most important sapphire producing areas. Large-scale mechanized mining and restoration techniques are the most effective means of utilizing this resource. The Central Volcanic Province has been divided into three prospective target regions. These comprise a western region with potential for Tertiary deep-lead diamond deposits, a central belt with Eocene-Oligocene deep-lead sapphire deposits, and an eastern division with Holocene alluvial sapphire deposits. A detailed palaeotopographic reconstruction technique has not been applied previously to the search for economic deposits of diamond or sapphire in the Central Volcanic Province. This method has proved to be a valuable exploration tool for delineating palaeochannels containing the above-mentioned deposits. Uranium-lead isotope dating of two zircon inclusions in sapphires from the Central Province, New South Wales gave ages of 35.9 ± 1.9 and 33.7 ± 2.1 million years (Ma). These ages fall within the range of basal potassium-argon ages (19 to 38 Ma) and zircon fission track ages (2 to 49 Ma) for the timing of volcanism in the Central Province. These data, combined with the observation that corundum is found with many alkali basaltic provinces, indicate a genetic link between the growth of large corundum crystals and contemporaneous processes involved in alkali basaltic magma generation. The abundance of incompatible elements such as U, Th, Zr, Nb, and Ta in inclusion minerals, indicate that the melt/crystallization process is not simple. Corundum and other minerals (such as zircon, columbite, thorite, uranium pyrochlore, alkali feldspar etc.) found as inclusion in corumdum, could not have been crystallized from most basaltic compositions. A more complex process must occur in which crystallization of coarse aggregates take place when high proportions of incompatible elements and volatiles are present in early melt fractions. These unusual crystallization products are subsequently transported to the surface by voluminous basaltic magmas. The extent to which this process occurs, and the rate of transport to the surface, presumably determined whether a particular basaltic province carries sufficient corundum to be worked into economic concentrations of sapphire. The majority of surface features observed on rubies and sapphires of volcanic origin reflect their trigonal crystal strucuture and are the result of layer dissolution or etching that that occurred while the crystals were exposed to the hostile melt environment Magtouf H. Gatei
A series of research studies on bovine leukemia virus (BLV) infection was designed to investigate viral infectivity, oncogenicity and immunological responses in cattle (natural host) and sheep (experimental model). The research also concentrated on the possibility of developing an efficient vaccine against this retroviral infection.
Serum concentrations of immunoglobulins IgG1, IgG2 and IgM over the same observation period were also studies. There was a significant decrease (P<0.0001) in the level of IgM in the sera of BLV+PL+ cattle compared to that in BLV+PL- and healthy cattle. There were no significant differences in Ig61 and Ig62 concentrations between the three cattle groups.
Twelve sheep were injected with phytohaemagglutinin cultured peripheral blood mononuclear cells from a naturally infected BLV+PL+ donor cow and their responses compared to 7 control sheep. The massive appearance of lymphoid cells in the blood of infected sheep indicated tumour development as confirmed histologically by peripheral lymph node (LN) biopsy performed at the time of lymphocyte proliferations. Nine out of 12 sheep (75%) died due to lymphosarcoma over a 10 - 22 months period. Gross tumours were usually found in the heart and mesenteric LNs of all leukemic sheep. Occasionally, the tumours were also detected in the abomasum, urinary tract and uterus. The liver, spleen, kidney and lung showed no solid tumours but were infi1trated with malignant lymphoblastic cells whether or not they showed gross involvement. A significant transient elevation of circulating lymphocytes in these sheep was also observed at 2 weeks after infection.
Synthetic overlapping peptides covering the entire sequence of the BLV gp51 antigen (Ag) were tested on peripheral blood mononuclear cells (PBMCs) from BLV infected and healthy cattle and sheep to determine the immunodominant T cell epitopes, The results provide evidence that residues corresponding to the sequences 61 - 70 and 131 - 14G amino acids of the gp51 Ag constitute the immunogenic sites of T4 (CD4) and T8 (CDS) epitopes respectively. The incorporation of these sites may be useful in the development of an efficient vaccine against BLV infection.
Vaccination of recipient sheep with vaccinia virus vectors expressing BLV envelope (env) gene (gp51 and gp30) or gp51 alone was carried out. The recipient sheep were subsequently challenged with 4 x 104 PBMCs from a BLV+PL+ donor cow. Vaccination with recombinants of BLV env gene induced high levels of T4 pro1iferation following booster vaccine inoculation. At two weeks after challenge, these sheep developed a slight increase in the gp51 antibody titres. Th
Fuxiang He
The Middle Jurassic and lower Cretaceous sandstones of the Great Australian Basin (GAB) in NSW (i.e., Eromanga and Surat Basins) comprise two petrofacies: a fluvial quartzose petrofacies and a lacustrine to marginal-/shallow-marine volcanolithic petrofacies. Detrital mineralogy, chemical composition of detrital feldspars (AnAbOr%), detrital mode (QFL%) and regional petrofacies distribution of these sandstones indicate the existence of two major provenances: for the quartzose sandstones, a dominantly cratonic provenance consisting of plutonic/metamorphic basement rocks and/or older sedimentary successions flanking the GAB on the west and south; and for the volcanolithic petrofacies which are rich in andesitic VRFs, a mainly contemporary volcanic orogen located along the northeastern continental margin of Australia. A regionally developed stratigraphic alternation of these two petrofacies defines a recurrent petrologic cycle that manifests contemporary episodic tectonic activity of the volcanic orogen – craton couplet. The Early Cretaceous marine transgression in GAB also extended into the Lower Cretaceous Murray Infrabasin (MIB), but the lithic sandstones of MIB are rich in metamorphic rock-fragments reflecting local provenances different from those that sourced the GAB proper. Diagenetic processes in the sandstones include physical compaction, clay infiltration (in some quartzose sandstones), dissolution/alteration of labile grains (e.g., VRPs, feldspars and mica) and cementation. In the volcanolithic sandstones, the diagenetic minerals comprise smectite, zeolite, kaolinite, carbonate and minor chlorite and illite; in the quartzose sandstones, the suite consists of kaolinite and quartz plus some carbonate and minor smectite and chlorite. Dissolution and cementation (and the occurrence of secondary porosity) in the volcanolithic sandstones are believed to be related to the acidic pore-fluids partly derived from diagenesis of the intercalated organic-rich mudrocks. The chemical diagenesis (and the development of secondary porosity) in the quartzose sandstones, which constitute some of the main aquifers in the Great Artesian System, results from the interaction between the meteoric pore-fluid and sandstone constituents.
In the lithic sandstones, core porosity ranges from 24.0% to 40.0% (with mean 35.0%), permeability from 1.8 to 4805.2 (md) (with mean 125.0 md); in the quartzose sandstones, these values are 16.3% to 34.2% (with mean 29.0%) and 1.3 - 18400.0 (md) (with mean 676.l md) respectively. Results of petrography, SEM and mercury intrusion porosimetry show that the volcanolithic sandstones contain mainly microporosity, and the quaztzose sandstones contain mainly primary and secondary intergranular porosity. The distribution patterns of porosity and permeability in the lithic and quartzose sandstones have good correlations with their respective depositional environments.
Parameters influencing sandstone porosity and permeability were examined using stepwise multiple regression. Porosity of the lithic sandstones (Q < 50.0 whole-rock%) is closely related to sediment age, content of detrital quartz (Q) and pore-fillings and burial depth (the multiple correlation coefficient r = 0.81); for the quartzose sandstones (Q > 50.0%), the parameters are burial depth, formation temperature and pore-fillings (r = 0.78); porosity of very quartzose sandstones (Q > 75.0%) is correlated closely with sediment age and grain-size (r = 0.85). Permeability of the lithic sandstones is related to pore-fillings, burial depth, detrital quartz and pore fluid chemistry (r = 0.66); for the quartzose sandstones, the parameters are grain-size, burial depth, formation temperature and sediment age (r = 0.75).
Factor analysis reveals the relationship among the petrological and petrophysical variables, and the relationships between these variables and the geological processes of source-rock weathering, sediment transportation and deposition, and diagenesis. Four factors have been established: Factor I is defined by grainsize, sorting, and pore-fluid chemistry; Factor II, defined by porosity and pexmeability and the content of matrix and detrital quartz; Factor III is defined by formation temperature, burial depth and sediment age; Factor IV is defined by the content of cements.
Based on the existing geological and geochemical evidence, there exists no petroleum source within the Eromanga Basin succession in NSW. In South Australia and Queensland, some of the Eromanga Basin hydrocarbon was likely generated in the Middle Jurassic Birkhead Formation and the Upper Jurassic - Lower Cretaceous Mura Member/Mooga Formation; but much of the Eromanga Basin hydrocarbon is likely to have been derived from the underlying Cooper Basin source rocks.
Arron S.L. Xu
An abstract from the thesis submitted to the University of Sydney for the degree of Doctor of Philosophy, December 1992.
Fluorinated solutes such ad difluorophosphate (DFP), monofluorophosphate (MFP), hexafluorophosphate (HFP) and trifluoroacetate (TFA) all showed well-resolved 19F NMR resonances when they were added to erythrocyte suspensions. The broader resonances from intracellular soutes was shifted to high frequency with respect to their extra cellular counterparts.
The 19F NMR chemical shifts of the above-mentioned compounds were shifted to high frequency in the presence of proteins. An increase in temperature also led to a shift of the 19F resonances to high frequency. Results from this work support the hypothesis that the disruption of hydrogen bonding between the fluorine atom and the solvent water atoms, by hydrated haemoglobin, is the principal physical basis for the 'split peak' phenomenon see with erythrocyte suspensions.
The well-resolved 19F NMR resonances of DPP enabled its transmembrane mass-distribution to be determined directly from an erythrocyte suspension. At transmembrane electrochemical equilibrium, the distribution of DFP was goverened by the membrane Donnan potential. The membrane potential measured using DFP was independent of the concentration of the probe molecule, and the haematocrit of the suspensions with a large range.
A novel adaption of a 19F NMR magnetisation-transfer technique was derived to measure the rapid membrane transport of DFP. The transport was shown to be mediated exclusively by band-3. The transport was temperature dependent; the 'break-point' temperature of the equilibrium efflux was -31oC. Under similar conditions, the ratios of the influx rates for solutes at a concentration of 20 mM were DFP:hypophosphite:F-:Cl- were 1.0:1.5:33.0:68.1.
The membrane-transport of TFA in human erythrocytes was significantly slower that DFP. By differentiating the inhibition brought about by a number of compounds, including stilbine disulfonates, α-cyano-4-hydroxycinnamate, p-chloromercuriphenylsulfonic acid, and N-ethylmaleimide, band-3 was found to be the dominant transporter of TFA uptake into human erythrocytes. A small fraction of the uptake was mediated by the monocarboxylate transporter. Under physiological conditions, transport via simple diffusion via the lipid of the membranes was negligible.
The 19F NMR spectrum showed well-separated quartets arising from beryllofluorides BeF2, BeF3- and BeF42-. This phenomenon facilitated the study of the multiple equilibria associated with the complexes in a solution. In erythrocyte suspensions, the 19F NMR spectra showed resonances from the intracelluar populations of the complexes shifted to higher frequencies relative to their extracellular counterparts. The erythrocyte membrane-transport of the complexes was completely inhibited by stilbene disulfonates; the results suggested that band-3 was the exclusive transporter for BeF42-, and intracellular BeF2 arose as the result of the redistribution of the various intracellular complexes via the multiple equilibria.
The 9Be NMR resonances of the complexes were, a quintet, a quartet and a triplet for BeF42-, BeF3- and BeF2, respectively, and they overlapped extensively. 9Bc NMR decoupling simplified the 19F NMR spectrum. The 19F magnetisation transfer among various complexes in either cis or trans compartments indicated interconversion among the different species in the cis compartment, and the transmembrane exchange occurred within sub-minute time scale. Michael John Oudshoorn
A thesis submitted for the Degree of Doctor of Philosophy in the Department of Computer Science, University of Adelaide, 1992
Programming language semantics are usually defined informally in some form of technical natural language, or in a very mathematical manner with techniques such as the Vienna Definition Method (VDM) or denotational semantics. One diffculty which arises from serious attempts to define language semantics is that the resulting definition is generally suitable for a single limited kind of reader. For example, the more formal kind of definition may suit a compiler writer or a language designer, but will be less convenient for other potential classes of reader, such as programmers. The latter frequently make use of some completely separate description (e.g., an introductory text book on the language); not surprisingly, inconsistencies between these separate descriptions and the language definition are commonplace.
Vol 123 parts 3-4, pp.85-86 [1991]
[Return to Volume's Index]
Doctoral Thesis Abstract: Stereochemical Studies on Metal Chelates of Novel Asymmetric Ligands
Vol 123 parts 3-4, pp.87 [1991]
[Return to Volume's Index]
M.Sc. Abstract: Late Pleistocene Geocryology of the Bogong High Plains
Vol 125 parts 1-2, pp.19-21 [1992]
[Return to Volume's Index]
Doctoral Thesis Abstract: Alluvial Sapphire and Diamond Deposits of the New England Gem Fields, New South Wales, Australia
Origin of Corundum Associated with Volcanic Provinces
Sapphire Inclusion Studies
Sapphire Surface Features
Vol 126 parts 1-2, p. 89 [1993]
[Return to Volume's Index]
Doctoral Thesis Abstract: Some aspects of the pathogenicity and immunity of bovine leukemia virus infection in cattle and sheep.
Specific monoclonal antibodies were used to identify lymphocytes bearing surface immunoglobulin, T he1per (BoT4), T cytotoxic (BoTS) cells and total T cell phenotypes over a four months observation period, The results showed that the numbers of B cells in BLV infected cattle with persistent lymphocytosis (PL) were significantly (P < 0.01) higher than those of BLV+PL- and BLV free cows. The percentages of bovine major histocompatibility determinants, BoT4 and BoTS T cells, were significantly reduced (P<0.01) in BLV+PL+ cows.
Intravenous inoculation of sheep was used to test the infectivity of blood and nasal and saliva secretions from BLV+PL+, BLV+PL- and BLV free cows. 1t was found that 200 to 20,000 lymphocytes from BKV+PL+ donors induced infection in recipient sheep within 3 - 8 weeks post infection (P.I.). The inoculation of blood from BLV+PL- donors did not induce seroconversion in recipient sheep over 24 weeks of the observation period. Inoculation of saliva and nasal secretions from all BLV infected donors failed to bring about SLV transmission. A significant but transient increase (P < 0.05) in the peripheral blood lymphocytes was observed in recipient
Vol 126 parts 1-2, pp.90-91 [1993]
[Return to Volume's Index]
Doctoral Thesis Abstract: Provenance, Diagenesis and Reservoir Characteristics of Sandstones of the Great Australian Basin Succession in NSW
Vol 126 parts 1-2, p.87 [1993]
[Return to Volume's Index]
Doctoral Thesis Abstract. 19F NMR of Erythrocytes: 'Split Peak' Phenomenon, Membrane Potential and Membrane Transport
Vol 126 parts 1-2, p.88 [1993]
[Return to Volume's Index]
Doctoral Thesis Abstract. Atlantis: a Tool for Language Definition and Interpreter Synthesis
The semantic technique described in this thesis lends itself to the semi-automatic generation of an interpreter from the language definition, a fact which acts as an incentive to language designers to produce a formal definition of any new programming language, since the prototype implementation allows experimentation with new language features and their semantics. The system which generates an interpretive implementation from a language definition is called ATLANTIS, A Tool for LANguage definiTion and Interpreter Synthesis, and is also described in this thesis.
Vol 126 parts 3-4, p. 199-200[1993] |
[Return to Volume's Index] |
Doctoral Thesis Abstract: Porphyrin-Based Building Blocks
Steven J. Langford
The work described in this thesis is aimed at the design and synthesis of a range of porphyrin-based molecular building blocks that can be assembled into extended systems or "Π-ways". The synthetic strategy involves the condensation of two building blocks: a porphyrin bis-(α-dione) system and a bis-(α-diamine) system; the extended "Π-way" being generated through the aromatic nature of the porphyrin macrocycle and their bridging units. The porphyrin-based building blocks fall into three categories; those leading to extensions (i) in a linear sense, (ii) through a right angle or (iii) through metal coordination. In each instance, the porphyrins are extended laterally through the regiospecific functionalisation of the porphyrin periphery.
The regiofunctionalisation of the porphyrin periphery is controlled by regiospecific bromination which directs the subsequent nitrations to the desired positions. The tetrabromination of tetraarylporphyrins occurs specifically at Δ2,3 and Δ12,13 through a bond fixed chlorin inter-mediate. The subsequent dinitration at the 7,17- and 7,18 positions illustrate that the bromo groups act as efficient blocking groups. Similarly the bromination of 2,3-dioxo-5,10,15,20-tetrakis(3,5-di-tert-butylphenyl)porphyrin occurs regiospecifically on Δ12,13 causing the nitration to be directed onto adjacent pyrrolic rings. The nitroporphyrins are the precursors to the desired α-diketones. This approach has been successfully used to furnish linear and two-dimensional porphyrin assemblies (1-3).
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Investigations into the use of phenanthroline-appended porphyrins in the fields pertaining to molecular magnets and molecular electronics have been initiated. These porphyrins have been functionalised in such a way as to complement the aforementioned studies. As a model for extended systems, the zinc(I1) and copper(l) bis-porphyrin -implexes were synthesised. These compounds show the usefulness of 1,10-phenanthroline as a bidentate ligand and are the first examples of systems in which two porphyrin structures are entirely non-covalently linked to each other.
Functionalisation of the outer periphery with respect to the direct replacement of the bromo groups and a new approach to porphyrin 2,3-diones via 2-hydroxyporphyrins is discussed. Studies were initiated in which the need for 1,2,4,5-benzenetetramine has been eliminated. Alkyl extensions to TPP derivatives, to enhance solubility, have also been studied.
The molecular structure of 2,3,12,13-tetrabromo-5,10,15,20-tetrakis(3,5-di-tert-butylphenyl)porphyrin and its nickel(II) chelate have been unequivocally assigned by X-ray diffraction data. The use of X-ray and 1H NMR techniques show that the free-base macrocycle is bond fixed into an 18 atom 18 π-electron aromatic delocalised pathway with the isolated double bonds, Δ7,8 and Δ17,18. The observed ruf configuration in the monoclinic crystalline form of the Ni(II) porphyrin is a consequence of the very small Ni-Nav distance (1.88 &Angst;) and is by far the smallest yet seen in a nickel(I1) porphyrin molecule.
Vol 126 parts 3-4, p. 201-202[1993] |
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MASTER OF SCIENCE THESIS ABSTRACT: CRATERFORM ORIGIN DERIVED BY QUANTITATIVE GEOMORPHOLOGY
MARK A. BISHOP
Spacecraft exploration of the solar system has supplied quantitative geomorphology with a plethora of enigmatic landscapes from which to further understand both geologic and geomorphic processes. For example, the relative dating of planetary surfaces using impact crater size-frequency distributions, has identified the exotic diversity of impact morphologies present on both silicate and ice rich planetary crusts.
Impact craters ~2-20 kilometres in rim crest diameter have provided the most meaningful chronological information (Greeley et al., 1987), although it is assumed that only impact craters are sampled, and that crater genesis can be readily Determined. However, Pike (1980) has demonstrated that multivariate analysis using morphometric parameters could not differentiate the origin of craters less than 5 kilometres in diameter. This posed an immediate problem with crater size-frequency distributions, as nearly all simple impact craters fall below this dimension for Earth, Moon, Mars and Mercury.
Nonetheless, planimetric circularity is a single morphometric element that has previously given limited success in differentiating the origins of impact and volcanic craterforms. Various techniques at determining an index of circularity have been demonstrated by Ronea and Salisbury (1966), Murray and Guest (1970) and Pike (1974). However in these instances, the identification of crater genesis was not absolute.
Although several mensurative methods are possible, in this study, the technique termed circumscribing-inscribing circles (C2), has proven the most accurate and reliable technique with which to measure a crater's planimetry. The definition of circularity using (C2), is a measurement of the ratio of the area of an inscribed circle (fitted to the crater rim crest) to the area of a circumscribed circle (Pike, 1974). For example, a circle has an index of circularity equal to 1.00, while with decreasing circularity the index approaches zero.
Following the derivation of circularity, parametric statistical procedures have shown that the point of segregation between the two crater types, lies at a circularity value of 0.68. It was revealed that impacts are represented by values greater than 0.68 while craters of endogenic origin fall below the 0.68 index. For the 124 craterforms measured, the accuracy for segregating maar and impact morphologies was approximately 86 percent. Although this technique of analysis is relatively simple, it is superior when compared with analyses that use a multivariate approach on craters of simple morphologic class.
As this procedure was found to be effective at determining a terrestrial craterform's mode of origin, the application of Pike's method to the lunar Alphonsus dark halo craters was also undertaken. Previous geologic investigations have indicated these features to be of a pyroclastic nature resembling maar-like volcanoes (Head and Wilson, 1979). Quantitative analysis of these structures' circularity, gives further support to this hypothesis. Although there is little debate about the prevalent impact origin of the moon's "pocked" landscape, it is evident that the origin of extra-terrestrial landforms can be accurately derived from morphometric analysis.
The identification of crater origin is an important aspect for both stratigraphic interpretation and the relative dating of planetary surfaces. The study of crater morphometry and morphology will be of immediate use in the interpretation of the Magellan radar imagery of Venus. By the application of standard quantitative geomorphological practices, a fuller understanding of both terrestrial and extra-terrestrial landscapes is achieved.
References:Greeley R., P.R. Christensen and J.F. McHone (1987) Radar characteristics of small craters. Implications for Venus. Earth, Moon & Planets. 37, 89-111.
Head LW and L. Wilson (1979) Alphonsus Dark Halo Craters. Proceedings of the Lunar and Planetary Science Conference. 10, 2861-2879.
Murray J.B. and LE. Guest (1970) Circularities of craters and related structures on Earth and Moon. Modern Geology. 1, 149-159.
Pike RJ. (1974) Craters on Earth, Moon and Mars. Multivariate classification and mode of origin. Earth and Planetary Science Letters. 22, 245-255.
Pike R.J. (1980) Geometric interpretations of lunar craters. U.S. Geological Survey Professional Paper. 1046-C, pp 77.
Ronca L.B. and LW. Salisbury (1966) Lunar history as suggested by the circularity index of lunar craters. Icarus, 5, 130-138.
Vol 126 parts 3-4, p. 203-204[1993] |
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Ph.D. Thesis Abstract. The Role of Thrombosis in Ischaemic Necrosis of Bone (INB) and Primary Osteo-arthritis (OA)
P. A. CHERAS
This thesis describes the evolution of a study that commenced as a comparison of idiopathic ischaemic necrosis of bone (INB) and primary osteo-arthritis of the hip (OA). These two conditions were initially regarded as being quite distinct. However the results of the studies presented in this thesis have led to the conclusion that INB and OA are qualitatively very similar and differences are probably only quantitative. The two conditions represent parts of a spectrum.
The initial hypothesis was;"that both non-traumatic ischaemic necrosis of bone (INB) and primary osteo-arthritis (OA) of the hip are caused by intra-osseous small vessel thrombosis".
A histological investigation of femoral heads removed at total hip replacement arthroplasty was commenced. The test groups comprised patients who had been diagnosed as having either idiopathic INB (16 femoral heads) or OA (11 femoral heads). The control group comprised patients who died without evidence of either INB or OA (7 femoral heads). The primary aim of the histological study was to seek evidence of microvascular thrombosis in femoral head bone.
Both test groups showed evidence of intraosseous thrombosis (recent and established), with Haematoxylin and Eosin H&E) and Martius Scarlet Blue stains.
Thrombi were found throughout the femoral heads, particularly in small venous vessels. Furthermore, intravascular lipid deposition was demonstrated in both groups with Oil Red 0 stain, confirming the appearance of lipid in H&E stained sections. These findings were not observed in the control group.
A novel double radio-isotope technique was developed using 125I labelled human fibrinogen and 99mTc labelled red blood cells. This indicated that femoral head bone from both INB and OA patients contained high concentrations of fibrin and/or fibrinogen compared with control levels.
In both these studies the only differences detected between the two test groups were in the severity or degree of change.
These studies were then followed by further experiments designed to test a second hypothesis which was;
"that OA of the hip is associated with systemic coagulopathy".
A study of the coagulation profiles of patients with OA was then undertaken to see whether the local changes that had been demonstrated in the femoral heads could be linked with systemic evidence of hypercoagulability.
The results show that in 33 persons with primary OA of the hip compared with 38 age, weight and sex matched controls, there is blood hypercoagulability, increased fibrin formation and decreased fibrinolytic competence. Statistics were performed using Student's two tailed t-test for unpaired samples. Significance was defined as p < 0.05. In OA patients there were significantly increased levels of factor VIIIc, platelet response to ADP, euglobulin clot lysis time, D dimer, plasminogen activator inhibitor type I, polymorphonuclear leukocyte elastase, cholesterol, LDL cholesterol and triglyceride versus levels in controls. Platelet aggregation threshold was significantly lower in OA patients.
These studies support a primary role for coagulation abnormalities (modulated by lipids) in the pathogenesis of OA. Osteoarthritis and ischaemic necrosis of the hip may both result from obstruction of susceptible microvasculature. The difference between the two diseases may only be the degree of the coagulation defects and timespan over which they occur. Haematological tests may be useful fr future laboratory diagnosis of primary OA.
Vol 126 parts 3-4, p. 205 [1993] |
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Doctoral Thesis Abstract: Reconciling the Roles of Status and Behaviour in Group Influence: Towards a Status-Confirmation Model
PHILIP B. MOHR
This thesis addresses the task of reconciling two discrete bodies of evidence relating to the emergence of influence hierarchies in small groups. Reviews are presented of research (1) documenting the phenomenon of status generalisation, and (2) identifying individual differences in nonverbal behavioural style as the basis of group differentiation. It is argued that previous attempts to integrate the two fields are flawed on two counts: the failure to differentiate empirically between the effects of nonverbal signals and those of differential task performance, and the corresponding tendency to depict such behavioural signals as a sufficient determinant of group structure. Findings obtained with behaviour separated from performance support the view that effects previously attributed to behavioural stimuli derived, instead, froiry differential task performance.
A status-confirmation model of the interactive effects of status and behaviour is proposed and evaluated. The primary assumption that behavioural confidence and the initiation of activity represent claims to situational status was endorsed by undergraduate subjects' accounts of the likely behaviour of a group member who seeks to attain group leadership. That established, the statusconfirmation model proposes behavioural statusclaims to be subject to confirmation or denial on the basis of the external status or competence of the claimant. Results of a field study, using extraversion as an index of a status-claiming behavioural style, support this argument; extraversion differentiated observer-rated influence of group members ranked high on either diffuse or specific status, but not those ranked uniformly high or low on both. The latter case, in particular, is inconsistent with the view that behavioural confidence plays an independent causal role, comparable to that of external status, in hierarchy formation.
Evidence, also noted, of the ability of external status to influence the perception of behaviour, permits reconciliation of the statusconfirmation model with the research base of status characteristics theory. Indications that the effects of behaviour on hierarchy formation are due to the pre-emption of leadership rather than the communication of confidence are considered, and the implications for the direction and methodology of future research discussed.