The hydrolytic degradation of a series of β-sultams and β-lactams was investigated using isothermal microcalorimetry (IMC), to determine kinetic and enthalpic data. The importance of these studies was to model the process of hydrolysis as this was a simplification of the mechanism by which β-lactams and β-sultams function as serine protease inhibitors. Calorimetric studies were conducted using a Thermal Activity Monitor (TAM 2277). Three categories of experiments were conducted: in the solid state, varying relative humidity (R/H) and in aqueous solution. Hydrolytic rate constants and enthalpies were determined for the solid state studies and these were related to substituent effects. However, for the experiments relating to the R/H studies no conclusive results were obtained. As expected, for solution state studies the hydrolytic rate constant in all cases changed with temperature (298K, 310K and 323K). Theoretical predictions were then made for a novel β-sultam based on these results with an excellent correlation observed between theoretical calculations and experimental results. Finally, calorimetric experiments were conducted on a series of β-lactams. This was for two reasons firstly; to determine if calorimetry can monitor low reaction rates and secondly; to compare rates of hydrolysis with the β-sultams. For a series of β-lactams, solution state hydrolytic rate constants and enthalpies were determined. An overall comparison of β-lactams and β-sultams appeared to indicate that in all cases β-lactams reacted slower than β-sultams.

This thesis describes the structural and preliminary electrical characterisation of various “shifted” hexagonal B-site deficient perovskites, of generic formula, A4B3O12. These ceramics are reported to possess promising microwave dielectric properties, which are a requirement for use in the ever evolving mobile telecommunications industry. The 12R crystal structures of the Ba3-xSrxLaNb3O12 series (x = 1 – 3) were refined at variable temperatures using NPD data in space group R-3 and some interesting behaviour was exhibited. All compositions were found to be antiphase tilted, the extent of which being dependent on the A-cation size. Upon heating, the tilt angle for all members of the series was found to decrease, although no tilt transitions from R-3 to R-3m were witnessed for all phases up to 900 °C, and a change in the magnitude of permittivity at 1 MHz was observed for all members except, BaSr2LaNb3O12. Additionally evidence from preliminary low temperature data suggest relaxor ferroelectric type behaviour. Ba2SrLaNb3O12 was found to possess the most promising dielectric properties although room exists for further improvement of the quality factor (Q value). To facilitate further tuning of the dielectric properties, specifically Q, the Ba3- xSrxLaNb3-yTayO12 series (x = 0 - 3, y = 1 - 2) was investigated, with the introduction of Ta5+ on the B-site. Some interesting ordering of A- and B-sites was found to occur, and furthermore, Nb5+ was found to display a preference to inhabit the distorted environment of B(1), adjacent to the “shifted” region, compared to the undistorted B(2) site, in the perovskite block. Unusual microwave dielectric properties were displayed with all compositions exhibiting small and positive temperature coefficient of resonant frequency (TCF) values and significantly small Q values, the reverse of what is expected, thus implying that the B-site has some influence on TCF values in this case. The interesting dielectric properties may be explained by several factors, including, the increased strength associated with the covalency of the Ta-O bond compared to that of Nb-O and the presence of some significant impurity phases, particularly in the intermediate compositions that are richer in Ta5+. The LCR data collected revealed similar results as found for the Ba3-xSrxLaNb3O12 series (x = 1 – 3), highlighting the limiting nature of the temperature range which did not, in fact reflect the true response of the compositions’ behaviour. All of the compositions are antiphase tilted at room temperature therefore the collection of variable temperature diffraction data is warranted. A range of novel Ta-based intergrowth compounds were synthesised and preliminarily characterised. No detailed structural or electrical data were collected for these compounds, however, the ability to form Ta-based intergrowths, in the first instance, has been established. It is postulated that by the formation of these intergrowth phases, the dielectric properties will be effectively tuned in comparison to those of the parent oxides that they are composed of, due to the regularisation of the octahedral layers that occurs upon the formation of such intergrowth structures. This often leads to improved TCF values, and by the introduction of Ta5+, can also give improved Q values. Ta5+ was substituted for Nb5+ in the untilted 5x6y (x = 1 – 3, y = 1) layered compounds, however, it was found that to facilitate this, the replacement of Ba2+ for Sr2+ was also required on the A-site. This double substitution was a requirement to obtain compositions closer to single phase Ta-rich phases compared to Nb-rich compositions.

The objective of this work has been to study the binding of metal ions to complex ligands expressing two or more metal binding sites, in terms of the thermodynamics of the binding events, and to use this information to contribute to the understanding of both the metal binding processes and the properties of the metal/ligand complexes. Two ligands have formed the basis of the study, one a naturally occurring enzyme and the other a newly synthesised ligand with two distinct binding sites (to form supramolecular complexes). The principle technique used to determine thermodynamic parameters has been isothermal titration calorimetry (ITC). The first system studied involved the enzyme β-lactamase II from Bacillus cereus 569/H/9 (BcII). The binding of zinc (II), cobalt (II) and cadmium (II) was investigated in aqueous solution at pH’s from 5.2 to 7.2. By using three or more buffers at each pH it has been possible to determine not only the binding constants of the metal ions at these pH’s but also the molar enthalpies of binding (and hence molar entropies). In addition, the dissociation of hydrogen ions from the enzyme on metal binding was also observed. In the case of all three metal ions, one metal ion per enzyme appears to bind at low pH and two metal ions at high pH (within the pH 5.20-7.20 range). In the case of zinc and cobalt ions two metal ions seem to bind per mole of enzyme in a cooperative mechanism. In contrast two cadmium ions appear to bind to the active sites of the enzyme non-cooperatively. For all three metal ions, models have been developed to describe the two binding sites and the sources of H+ ions that dissociate on metal ion binding. The second system studied involved the supramolecular synthesised ligand bipy-aza-crown-4. This ligand has two metal binding sites, one at the 2,2-bipyridine and the other at the aza-crown-4. The objective was to compare the way copper (II) binds in acetonitrile solution with the way in which the copper (II) complex with this ligand is crystallised from methanol solution with progressively increased copper (II) concentration, as revealed by single crystal x-ray diffraction. Smaller ligands that represent the two individual complexation regions of the synthesised ligand were also used for comparison. Both ITC and solution spectroscopic measurements were used to compare the binding model that was proposed in methanol solution. It was demonstrated in acetonitrile solution that copper (II) binds to the 2,2-bipyridine site first in a 1:2 (Cu2+:L) ratio, then binds to the aza-crown site in a 1:1 (Cu2+:L) ratio . So it was demonstrated that the overall stoichiometric ratio of copper ion to bipy-aza-crown-4 in the fully formed complex is 3:2 (Cu2+: L). Possibly the main conclusion drawn is that the order in which the binding sites are occupied in acetonitrile solution is different to that in which they are occupied in methanol.

The development of an enzyme biosensor employing a novel functionalised polythiophene matrix is presented. The research upon conducting polymer platforms for biological immobilisation is extensive but by no means exhaustive and therefore this investigation contributes to the field of glucose detection with covalently immobilised glucose oxidase upon novel copolymers of N-succinimido thiophene-3- acetate/3-methylthiophene (STA-MT), trans-3-(3-thienyl) acetic acid/3- methylthiophene (TTA-MT) and N-succinimido trans-3-(3-thienyl) acetate/3- methylthiophene STTA-MT. Polymer characterisation was performed using electrochemical techniques, primarily cyclic voltammetry. The examination of various substituted conducting polymers from the polythiophene family was performed where 3-methylthiophene was selected for copolymerisation due to its low oxidation potential and redox behaviour. Copolymerisation of the novel monomers provided reversible and stable films and succeeded in generating a range of copolymer ratios characterised by cyclic voltammetry with the available binding sites calculated using SEM-EDX. Film morphology and dopant intercalation were investigated, providing supporting evidence for the successful copolymerisation of novel monomers with 3- methylthiophene. Optimisation of the biosensor format was investigated through analysis of film thickness, copolymer ratio and enzyme immobilisation time. A film thickness generated with 50 mC provided a stable film with good response to glucose over a wide range of immobilisation times and was employed for all other biosensor investigations. A 10% functional monomer content provided enhanced current signals upon glucose addition which supported the findings of Kuwahara et al where a 10% thiophene-3-acetic acid content within a thiophene-3-acetic acid/3-methylthiophene copolymer demonstrated enhanced biosensor behaviour. All studies were compared against the thiophene-3-acetic acid and 3-methylthiophene system generated under the optimised conditions of the novel copolymer films. The evaluation of the immobilised glucose oxidase as an amperometric biosensor within a mediated system employing p-benzoquinone was performed generating fast response times within 4 seconds, good stability and excellent current response to glucose between 1.4 and 1.9 mA/cm2 after the addition of 15 mM of glucose. All three novel biosensor systems exhibit good analytical performance demonstrating excellent repeatability typically over 90%, reproducibility of over 80% and shelf-life stability of 85-96% over a seven day analysis and between 50-78% after 1 month.

In this project, the structures of exopolysaccharides (EPS) produced by bacterial strains were characterised. The current techniques utilised for structural elucidation were also investigated. The structure of the novel EPS isolated from the fermentation of the lactic acid bacteria(LAB) strain, Lactobacillus helveticus Rosyjski, has been characterised. The strain of LAB was grown on skimmed milk supplemented with glucose; the subsequent EPS produced was isolated using established protocols. The 1H NMR spectrum identified the presence of five anomeric monosaccharide signals corresponding to the existence of a pentasaccharide repeating unit oligosaccharide. HP-SEC-MALLS analysis revealed the EPS has a weight average molecular weight of less than 1.4 x106 g mol-1. A combination of GC-MS and HPAEC-PAD analysis confirmed that the structure was composed of D-glucose, D-galactose and D-N-acetyl mannosamine in a molar ratio of 2:2:1. Linkage analysis of the EPS, by GCMS and 2D-NMR experiments showed that the repeating unit contains two terminal, one dilinked and two tri-linked monosaccharides. All of the data obtained allowed for the elucidation of the structure of the EPS produced by Lactobacillus helveticus Rosyjski. The current techniques used for the determination of the monomers and linkages present in EPS structures were investigated. Monomer analysis was studied by using the previously characterised EPS, Lactobacillus acidophilus 5e2 as a model. A variety of acids were used to catalyse the hydrolysis of the polysaccharide. The monosaccharides liberated from the EPS were analysed by HPAEC-PAD. It was determined that hydrolysis with TFA was the simplest technique to employ whilst also providing reliable results. Linkage analysis was investigated by the production of a number of disaccharide-derived model linkage standard compounds. This resulted in the creation of a number of terminally and di-linked linkage standards which can be used as model reference compounds when characterising previously unidentified EPS. The bacterial strain Bifidobacterium animalis subsp. lactis A1dOxR produces EPS. Initial inspection of the 1H NMR spectrum however displayed a complex anomeric region with many overlapping signals. Analysis by HP-SEC-MALLS revealed multiple peaks, further adding to the evidence of the presence of more than one EPS in the recovered ‘crude’ sample. The crude sample was subjected to dialysis and a fraction (over 100,000 Da) was recovered and denoted as high molecular weight (HMW) EPS. Examination of the 1H NMR spectrum from HMW EPS indicated a hexasaccharide repeating unit oligosaccharide, whilst HPEAC-PAD and GC-MS analysis confirmed that the structure was composed of Lrhamnose, D-galactose and D-glucose in a molar ratio of 3:2:1. Further analysis determined that one of the galactose monosaccharides was present in the furanose form as appose to the more commonly observed pyranose configuration. Linkage analysis of the EPS, by GCMS and 2D-NMR experiments, showed that the repeating unit contains one terminal, four dilinked and one tri-linked monosaccharide. All of the data obtained allowed for the elucidation of the structure of the HMW EPS from by Bifidobacterium animalis subsp. lactis A1dOxR. Solubilising EPSs has been a constant challenge, however, it was hoped with the advent of ionic liquids (IL) this issue could be solved. Ultimately, dissolution of EPS in ionic liquids though proved to be unsuccessful, so attention was turned to combining derivatisation and dissolution, as a method for solubilising polysaccharides. Derivatisation of a number of model systems of di- and polysaccharides were explored. By studying both 1D- and 2D-NMR coupled with GC-MS analysis it has demonstrated that polysaccharides such as cellulose along with a number of common disaccharides can be successfully dissolved and modified in ionic liquids.

This thesis describes the synthesis of pyrrolizidines, indolizidines and pyrroloazepines from the reaction of cyclopropenones with a wide range of five, six and seven-membered cyclic imines. These three alkaloids nuclei are widespread in nature and have shown many potential pharmaceutical properties. The cyclic imines were typically synthesised by thionation and alkylation of their corresponding lactams, although other cyclic imines were investigated. The imines were then reacted with diphenylcyclopropenone (DPP). The pyrrolizidine, indolizidine and pyrroloazepine reactivity was exploited by oxidising the bridgehead group (X = S) with m-CPBA, giving rise to new products, including a sulfoxide elimination product, and an unexpected hydroxy compound. This was a useful discovery, given the presence of such a bridgehead OH in the jenamidine natural products. This thesis explores ways in which this may have occurred and also looks at alternative methods. The synthesis of cyclopropenones other than DPP is described along with attempts at reacting them with 5-membered cyclic imines (1-pyrrolines). Also included is a study of nitrile oxides as traditional 1,3-dipoles and their reaction with 1- pyrrolines. Finally, an exploration of the reactivity of diphenylcyclopropenone with acyclic imines derived from Ellman’s 2-methyl 2-propanesulfinamide is included, which gave unexpected access to an indenone.

Tungstated Zirconia (WO3-ZrO2) is a technologically important catalyst; however, there is still a considerable lack of understanding for the presence of different WO3 surface species found in this catalyst which are responsible for its high activity. We report here the application of atomistic simulation techniques based on interatomic potentials to explore the nature of WO3 species on WO3-ZrO2 systems. At first modelling of the pure structure of t-ZrO2 was investigated and the reliability of computed structures was found to agree with earlier theoretical and experimental studies. An investigation of all low miller index pure surfaces of t-ZrO2 revealed the highest stability in the following order {101} > {001} > {111} > {110} > {100}. The adsorption of WO3 at partial monolayer coverages of 20 % and 50 % were then investigated onto the surfaces of t-ZrO2. Conclusions that can be drawn from this work are that the preference WO3 species for a particular surface depended on the type of the surface and temperature considered. The highest favourability to WO3 addition was detected on the {111} surface, where a 50 % monolayer coverage was found to be stable. The {100} and {110} surfaces were favourable to WO3 addition, although this favourability depended on the temperature and amounts of WO3 added. The surfaces {001} and {101} were not favourable to WO3 addition at low temperatures. The addition of WO3 resulted in stabilizing of surfaces which were otherwise unstable in t-ZrO2 such as the {111}, {110} and {100}. The study also confirms the formation of polymerized WO3 layers, dimers, monomers and Zr-WO3 linkages which were detected in earlier experiments. The nature of WO3 species were found to be surface specific, which also depended on the surface area and temperature. The knowledge obtained from this study could be used to design and optimize an efficient catalyst.

Background: Neuroinflammation in the central nervous system involves the rapid reaction of the CNS through activation of resident immune cells (especially microglia cells) to infection, trauma and stroke, among other stimuli. It is a tightly regulated process but in chronic cases it is detrimental. Uncontrolled neuroinflammation has been shown to manifest itself in various neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis (ALS) and multiple sclerosis (MS). The Nrf2/HO-1 antioxidant system has also been recently shown to be involved in neuroinflammation. Artemisinin, artemether and artesunate are antimalarial drugs that have been shown to possess anti-inflammatory activity. However, there is no detailed evidence demonstrating that these drugs could inhibit neuroinflammation in lipopolysaccharide (LPS)-activated BV2 microglia cells. Therefore, this study aims to investigate the effects of these compounds in LPS-activated BV2 microglia. This research also attempted to explore the possible involvement of the Nrf2/HO-1 system in the anti-neuroinflammatory action of these compounds. Methods: Cultured BV2 microglia cells were stimulated with LPS following pre-treatment with artemisinin (5-40 μM), artemether (5-40 μM) or artesunate (0.5-4 μM). Nitrite, used as a measure of nitric oxide production was investigated using the Griess assay. PGE2 production was investigated with PGE2 EIA assay, while cytokine production was measured using ELISA. Reporter gene assays in transfected HEK 293 cells were used to investigate effects of the compounds on NF-B and ARE luciferase activities. Further experiments to elucidate the mechanism of action of artemisinin, artemether and artesunate were carried out by measuring expressions of various target proteins in whole cell and nuclear extracts using western blotting. In addition, NF-B DNA binding was investigated using the EMSA. Subsequent investigations to understand the role of Nrf2 activity on the inhibitory activity of the compounds on NO, TNFα, IL-6 and PGE2 production in activated BV2 cells were carried out in Nrf2 silenced cells. To achieve this, BV2 cells were transiently transfected with Nrf2 siRNA followed by pre-treatment with compounds and stimulation with LPS for 24 hours. Results: Artemisinin, artemether and artesunate inhibited LPS-induced nitric oxide (NO), prostaglandin E2 (PGE2) and pro-inflammatory cytokine (TNFα and IL-6) production in LPS-activated BV2 microglia cells. These compounds also down regulated the expression of specific regulatory proteins, inducible NO synthase (iNOS) cyclooxygenase-2 (COX-2) and microsomal prostaglandin E2 synthase-1 (mPGES-1). Artemisinin, artemether and artesunate exerted anti-neuroinflammatory activity in LPS activated microglia by suppressing LPS-induced NF-B activity via inhibition of IB phosphorylation and degradation-mediated nuclear translocation of the p65NF-B subunit. These compounds also produced consistent inhibition of DNA binding of NF-B. All three compounds exhibited a similar profile in interfering with p38MAPK signalling following LPS activation of BV2 microglia by preventing phosphorylation of MKK3/6, p38 and MAPKAPK2. This research showed that artemisinin, artemether and artesunate activated Nrf2 mediated HO-1 antioxidant activity in BV2 cells. These effects appear to be mediated through the activation of the antioxidant response element (ARE). Further association studies revealed that artemisinin; artemether and artesunate caused reduction in TNFα, IL-6 and PGE2 secretion in LPS-activated BV2 cells through Nrf2-dependent mechanism. However, it appeared that their inhibitory action on NO production was independent of Nrf2 activity. Conclusion: Taken together, the outcome of this research indicates that artemisinin, artemether and artesunate suppress neuroinflammation in LPS-activated BV2 microglia by interfering with NF-B and p38MAPK signalling. The compounds also produced consistent activation of the Nrf2/HO-1 antioxidant protective system. This research has also provided the first evidence that the inhibitory actions of these compounds on TNFα, IL-6 and PGE2 are dependent on their ability to activate the Nrf2 transcription factor.

Amino acids are a ubiquitous class of compounds which are vital to the existence of all life on earth. In addition to providing the building blocks of life’s machinery, they are increasingly finding use as starting materials for total syntheses, as ligands in chiral catalysis or as novel pharmaceutically active compounds in their own right. As such, the development of new synthetic methods to access existing -amino acids, as well as previously unknown amino acids is of significant importance. The introduction contained in the first part of this report aims to provide a general overview of the catalytic methods currently used to prepare -amino acids, as well as to highlight a notable class of -amino acids called the kainoids, with specific attention directed to covering previous total synthesis routes to access (-)--kainic acid. The work described in the second part of this report was based on the extension of methodology developed by Shaw, and focuses on attempts to develop catalytic, diastereoselective aldol reaction methodology with azido hydroxamic acid-containing substrates in order to prepare diastereomerically pure -amino acids. The third and final section of this report discusses the preparation of substituted tetrahydropyridinium ylide precursors and their subsequent rearrangement in the presence of neutrally-generated benzyne is explored. The selectivity observed when asymmetric arynes are generated as reactive species was also investigated. Finally, the successful expansion of this methodology to acyclic substrates is also discussed.

It is known that Island Southeast Asia was colonised relatively early in the history of modem humans; however, it is still a matter of some debate as to whether the modem inhabitants of Island Southeast Asia are descended from these original inhabitants or are the result of some later migration. Currently, the prevailing theory in both archaeology and linguistics is that the modem inhabitants of Island Southeast Asia are largely descended from an agricultural people who originated in China and Taiwan around 6,000 years ago. From there they are thought to have migrated through the Philippines and into Eastern Island Southeast Asia around 2,500-1,500 B.C. assimilating or replacing the indigenous peoples. However, other researchers have suggested that a model of regional continuity is more suitable for Island Southeast Asia and that the modem inhabitants are the direct descendents of the original Pleistocene inhabitants. Still others have suggested that intermediate models would be more appropriate. This study aimed to use mitochondrial DNA to test the validity of these models. A secondary aim was to look at the mitochondrial DNA of the indigenous Orang AsH groups of the Malay Peninsula in an attempt to reconstruct a picture of the early Pleistocene variation of Southeast Asia. To this end, mitochondrial DNA was obtained and sequenced from 885 individuals from various locations in Island Southeast Asia and also 259 Orang AsHindividuals. This study has demonstrated that the populations of Island Southeast Asia contain a high level of genetic diversity, including a number of novel haplogroups. Significant differences have also been found between Eastern and Western populations suggesting that they have been established long enough to become regionally specific. Most Island Southeast Asian haplogroups date to the Pleistocene or early Holocene which suggests that they are mostly indigenous to the area. Those which could have a connection to Taiwan seem too old to have been part of an 'out of Taiwan' event as it has been traditionally visualised. Only -13% ofmtDNA types (belonging to haplogroups M7clc, D5 and Y2) could be linked to such an event suggesting that if a migration did occur it was demographically minor. xiii A number of novel haplogroups were also found in the Orang Asli which form strong support for the theory that that at least the Semang, if not all Orang Asli groups in part, are descended from the original Pleistocene inhabitants of the Malay Peninsula. These novel haplogroups diverge from the same set of founder types as the haplogroups found across the rest of Eurasia; that they diverge from close to the roots of these founder types suggests they are of considerable antiquity. This, along with expansion dates of -60,000 obtained in this study, suggests that only a single, early 'out of Africa' event took place which led to the peopling of the rest of the world by modem humans.