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Characterisation Of Microbial Colonies On Colorbond® Steel Substrates, Nicole Alexandra Pianegonda

University of Wollongong Thesis Collection 1954-2016

COLORBOND® Steel is a hugely successful, branded, coil-coated steel product used in a wide range of building application throughout Australia and South East Asia. Fungal growth on light coloured COLORBOND® Steel used in roofing and walling material is both unsightly and absorbs solar radiation, negatively impacting the roof and underlying structure. Up until now, however, the extent and behaviour of such fungal growth on these unique substrates has been poorly understood. Methods of assessing the phenomenon have, likewise, been lacking. Future development of strategies to prevent and mitigate infestation of these substrates is dependent upon the mechanism of infestation being …

Development Of Single Microdroplet Techniques For Fundamental Chemical Measurements, Bartholomew S. Vaughn

University of Wollongong Thesis Collection 1954-2016

A significant number of current techniques that probe chemical and physical processes in single microdroplets focus on the measurement of long timescale processes. Probing short timescale processes (<100 μs) in single microdroplet domains has been largely prohibitive. Therefore, new experimental techniques are required to probe short timescale chemical transformations in microdroplets. In this thesis, experiments on single free-falling microdroplets that probe chemistry and physics of photoactivated reactions are reported. Single microdroplets are generated using drop-on-demand droplet generation and subsequently interrogated using various pulsed laser systems. The principal advantage of single microdroplet techniques is that each microdroplet is a chemically isolated and self-contained reaction vessel. This allows chemical and physical transformations to be probed with no crosscontamination between microdroplets.

Development Of Mass Spectrometry-Based Methods For The Analysis Of Lipid Isomers, Rachel Kozlowski

University of Wollongong Thesis Collection 1954-2016

Glycerophospholipids, or phospholipids, are important biochemical components of many biological organisms. They are involved in many biochemical processes including signal transduction, serving as enzyme substrates for lipoprotein metabolism and serving as ligands for receptors and precursors of essential biomolecules; they are also intracellular traffickers of cholesterol as well as modulators of the immune system. Likely to fulfill these diverse functional roles, not only do phospholipids contain a variety of head groups attached to a glycerol backbone but even more diversity exists within the fatty acyl chain(s) that are attached to the same glycerol backbone. These differences can be very subtle …

Investigating Changes In Human Brain Phospholipids During Normal Ageing, Sarah E. Hancock

University of Wollongong Thesis Collection 1954-2016

The world’s population is rapidly ageing, and with that has come a corresponding increase in the number of people suffering age-related diseases. Dementia is a group of age-related neurocognitive disorders, with the most common of these being Alzheimer’s disease (AD). The number one risk factor for developing AD is advanced age, with the incidence rising from 1 in 10,000 at age 60 to 1 in 3 by age 85. AD is characterised by the deposition of extracellular amyloid-β aggregates (Aβ) and intracellular neurofibrillary tangles (NFTs) formed by hyperphosphorylated tau. Both Aβ and NFTs spread throughout the brain by separate but …

Dna-Binding Interactions Of Nickel Schiff Base Complexes, Nawal Masoud O Assadawi

University of Wollongong Thesis Collection 1954-2016

A series of eleven different nickel Schiff base complexes was synthesized by a two-step procedure. Initially ethylenediamine, phenylenediamine or meso- 1,2-diphenylethylenediamine was reacted with either 2,3- or 2,5- dihydroxybenzaldehyde in the presence of Ni(II) to afford six novel dihydroxylated nickel Schiff base complexes. Five of these complexes were then successfully reacted with 1-(2-chloroethyl) piperidine hydrochloride to form a series of derivatives featuring two appended ethyl piperidine moieties. All new complexes were characterised using 1D and 2D nuclear magnetic resonance (NMR) spectroscopy, elemental microanalysis and in some instances electrospray ionisation mass spectrometry (ESI-MS). The solidstate structures of three nickel complexes (5), …

Uncovering The Energies And Reactivity Of Aminoxyl Radicals By Mass Spectrometry, David Marshall

University of Wollongong Thesis Collection 1954-2016

Aminoxyl radicals (R1R2NO•) are a well-known class of stable free radicals and play a major role in polymer chemistry as both reagents for controlled polymerisation processes and polymer stabilisers. Both of these processes involve cycling between aminoxyl radical and alkoxyamine (R1R2NO–R3) forms. Despite their widespread industrial use, there is surprisingly little known about the intrinsic energetics and reactivity of these species that could inform our understanding of their behaviours in complex polymer matrices or reaction mixtures. In this thesis mass spectrometry is used to uncover these fundamental properties of aminoxyl radicals in the gas phase.

Alkoxyamines were prepared with an …

Phospholipids In Human Tears, Meibum And Deposited Onto Contact Lenses, Jennifer T. Saville

University of Wollongong Thesis Collection 1954-2016

The tear film is a complex mixture of proteins, mucins and lipids that forms a layer over the anterior surface of the eye and is vital in ocular health. The outer portion of the tear film contains a thin lipid layer, which prevents the excess evaporation of the aqueous phase and aids in the stability of the tear film. The tear film lipid layer contains both polar and non-polar lipids, with the polar lipids thought to act as a surfactant that spread the non-polar lipids across the aqueous surface to produce a stable tear film. Despite the importance of tear …

Noncovalent Interactions In The E. Coli Replisome: Novel Aspects Of Single-Stranded Dna-Binding Protein (Ssb) And The Β2 Sliding Clamp, Claire E. Mason

University of Wollongong Thesis Collection 1954-2016

This thesis presents analyses of key protein-protein and protein-nucleic acid interactions in the E. coli replication machinery. The E. coli single-stranded DNA-binding protein (SSB) is a central mediator of DNA metabolism, binding to regions of exposed single-stranded DNA (ssDNA) and playing crucial roles in DNA replication, recombination and repair. SSB is a stable homotetramer, held together by interactions between the N-terminal domains of its subunits. Structurally, the N-terminal domains form classic oligonucleotide-binding folds (OB-folds), and are also responsible for ssDNA binding. The SSB-ssDNA complexes may adopt a number of configurations, differing in the extent of SSB-ssDNA contact, and are heavily …

Mass Spectrometric Approaches For The Structural Characterisation Of Lipids By Ozonolysis, Michael Christopher Thomas

University of Wollongong Thesis Collection 1954-2016

Lipids are the main structural component of biological membranes and are important in complex biochemical processes including cellular signalling. Using electrospray ionisation-tandem mass spectrometry (ESI-MS/MS), information regarding fatty acid chain length and degree of unsaturation can be gained for complex lipids. Determining double bond position, however, remains challenging.

To address the limitations of collision-induced dissociation (CID) for structural characterisation, the use of ozonolysis chemistry in conjunction with mass spectrometry was explored. Initial experiments concentrated on performing ozonolysis within the electrospray source of conventional mass spectrometers; referred to here as ozone electrospray ionisation-mass spectrometry (OzESI-MS). In OzESI-MS experiments, two ozonolysis product …

New Capabilities And Applications Of Ambient Ionization Mass Spectrometry For The Surface Analysis And Imaging Of Lipids, Shane R. Ellis

University of Wollongong Thesis Collection 1954-2016

Mass spectrometry is arguably the most important technique used in lipid analysis. It provides unparalleled sensitivity and molecular specificity in the detection, quantification and structure elucidation of the diverse range of lipids present in complex biological matrices. The recent and rapid emergence of ambient ionization mass spectrometry presents new and exciting opportunities for the direct detection of lipids from surfaces, including those commonly encountered in lipid research such as tissue sections, cells and thin-layer chromatography plates. This thesis describes the application, optimization and analytical capabilities for two contemporary ambient ionization technologies - namely desorption electrospray ionization (DESI) and liquid extraction …

Investigating The Reactions Of Gas-Phase Radicals Using Distonic Ions, Benjamin B. Kirk

University of Wollongong Thesis Collection 1954-2016

Free radicals are involved as reactive intermediates in a diverse range of processes including hydrocarbon combustion, the formation of photochemical smog, lipid perox- idation, cell apoptosis, polymerisation and synthetic cyclisation reactions. The intrinsic reactivity of free radicals and the inherent difficulty involved in their controlled gener- ation and isolation has led the experimentalist to develop ever more complex methods of determining their ultimate fate in these reactions. A systematic mass spectrometric and computational study of archetypal charge-tagged phenyl and cyclohexyl radicals was undertaken to elucidate the reactivity of these radicals towards O₂. Central to this study was the …

Mass Spectrometric Analysis Of Proteins Of The Bacterial Replisome, Linda L. Jessop

University of Wollongong Thesis Collection 1954-2016

Electrospray ionisation mass spectrometry (ESI-MS) was used to investigate noncovalent interactions of E. coli DNA polymerase III (Pol III) protein subunits with metal ions, ligands and other Pol III proteins. Nanospray (nano) ESI-MS was used to examine the interaction between α(polymerase) and a recombinant version of the 16 kDa C-terminal domain of τ (τ_C16, a clamp loader protein) which retains the α binding site. Firstly, τ_C16 and various τ_C16 mutants and truncations were titrated into samples containing a constant amount of α. Based on the nanoESI mass spectra, the relative order of binding affinity …