Restricted Theses
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Item Restricted The Development of Amino Acid Sulfinate Salts as Tools for Peptide Modification(2024) Hammond, JoshuaModified peptides, including compounds inspired by nature, have increasingly become a valuable area of research due to their growing prevalence in medicinal chemistry. To fully exploit the potential of peptide natural products and their derivatives, novel techniques must be developed to access these compounds in a laboratory setting. Techniques which can mimic the site selectivity of enzymatic post-translational modifications are particularly valuable. One conceivable approach is the development of novel amino acids bearing unique functional groups that impart new reactivity onto a peptide. In this thesis , the synthesis of novel amino acid sulfinate salts as valuable precursors to amino acid radicals is explored. The established radical reactivity of the sulfinate moiety is ideal as the conditions for radical formation are generally mild and selective and radical transformations can often proceed orthogonally to polar functional groups , including the diverse functionality present in peptides. This work discloses the synthesis of amino acid sulfinate salts and the optimization of a photochemically-promoted radical reaction between these novel amino acids and various radical traps, particularly disulfides. In addition, this reactivity is extended to small molecule sulfinates and disulfide-containing peptides, for the development of an umpolung approach to the modification of cysteine residues. The thesis is divided into the following chapters: Chapter one summarises the existing literature on site-specific side-chain peptide modification, the development of the sulfinate moiety as a precursor for carbon centred radicals and the subsequent use of existing sulfinate reagents in the modification of small molecules and peptides. Furthermore, a brief history of photochemistry, focussing on the use of photochemistry as a tool for peptide modification, is discussed. The specific aims of this thesis are also outlined. Chapter two details the synthesis of the first amino acid sulfinate salts derived from the native hydroxy-functionalized amino acids hydroxyproline (HPro), homoserine (HSer) and serine (Ser), and summarises efforts towards the preparation of an amino acid sulfinate salt derived from threonine (Thr). Detailed optimization of the synthetic pathways are discussed. Chapter three focusses on the optimization and subsequent diversification of the amino acid sulfinate salts. Various mild oxidative conditions were probed for their effectiveness, including chemical oxidation, electrochemistry, and photochemistry. Optimization of key photochemical conditions enabled broad application to a functionally diverse array of disulfide radical traps. Chapter four aims to extend the reactivity of disulfides to a peptide context to investigate the feasibility of the reaction as a tool for the modification of cystine residues. Suitable peptide model systems were synthesized using solid phase peptide synthesis and small molecule sulfinates ('diversinates') are probed for reactivity with peptidic disulfides. Extensive optimization was conducted to improve reaction outcomes using high-throughput experimentation. This chapter also details the incorporation of amino acid sulfinates into a peptide as an alternative strategy for peptide modification. Chapter five summarises the advances made herein towards the development of sulfinate salts as tools for the modification of peptide substrates. Future directions are also discussed, including the incorporation of the amino acid sulfinates into peptides to enable to synthesis of biologically relevant peptides, such as the lanthipeptide family of natural products . In addition, the prospect of creating tuneable protected amino acid sulfinates for one pot modification techniques is discussed. Chapter six provides the detailed experimental protocols and characterization data for all compounds described in Chapters 2-4 of this thesis.Item Restricted Negative Campaigning in Indonesia's Digital Era Elections(2024) Simarmata, SalvatoreNegative campaigning can inform voters and ensure accountability, but it can also foster voter cynicism, divert attention from meaningful policy debates, and increase political polarization. In the digital era, negative campaigns have shifted from fostering informed discussion to employing manipulative tactics by focusing on the candidate's character, particularly issues of identity that have not been systematically investigated in Indonesian context. This thesis explores negative campaigning in the digital era in Indonesia marking the new wave of digital political communication by looking at its mechanics, actors, key narratives, and effects. To this end, the study analyses three elections: the 2019 presidential election, the 2022 mayoral election in Medan in Sumatra, and the 2022 mayoral election in South Tangerang in Java. Fieldwork for this thesis included conducting over two years of semi-structured interviews with key stakeholders, such as politicians and social media campaigners. In addition, content analysis was carried out on social media and other online media, as well as orchestrating various other surveys. The findings reveal that digital media has transformed the nature and professional practice of negative campaigning. Campaign actors, such as influencers and buzzers, operate covertly on various social media platforms, employing bots, automation, and anonymity to amplify messages, ranging from legitimate criticisms to slander and disinformation using computational propaganda. Key to this study is the identification of various negative campaign narratives, such as portraying opponents as disobedient to Islam, subservient to foreign interests, lacking integrity, or being associated with the Indonesian Communist Party. This thesis also highlights the impact of negative campaigning on voters, showing a feasible decrease in support for the targeted candidate. My key theoretical contribution to the literature lies in the cross-disciplinary integration of communication and politics in theories, methodologies, and argumentation, which significantly enriches the field of political communication research in recent time. My thesis found that negative campaigning is primarily dominated by character attacks that exploit the identity issues of candidates, rather than focusing on policies. The findings of this first systematic study with extensive case details in Indonesia enhance the understanding of computational propaganda in the world's fourth-largest democracy and highlight the need to mitigate their adverse effects. The findings also indicate the emergence of digital negative campaigning which is different from the old conception at the mass media era.Item Embargo Investigating how metabolite fluxes affect two brain diseases using different model systems(2024) Gao, XuexinThe work described in this thesis investigated the metabolite fluxes involved in two brain diseases, divided into two parts. Part A studied metabolite flux of ketone bodies in a glioblastoma cell line and compared with other cancer cell lines. Investigation of Part A concentrated at cellular level and the flux of ketone body metabolism was examined to illustrate how cells use ketone bodies for support of proliferation. The study was expected to tell us whether a ketogenic diet may be beneficial to glioblastoma treatment. Glioblastoma is an aggressive form of brain cancer, presenting significant challenges due to limited treatment options. While normal brain cells primarily utilise glucose for energy, they can adapt to alternative substrates such as ketone bodies. This study investigates whether different cancer cell lines retain the ability to utilise ketone bodies as energy substrates, with a focus on beta-hydroxybutyrate metabolism. The results revealed that all cell lines exhibited enhanced aerobic glycolysis, leading to lactate production in the presence of oxygen, with compensatory flux from glutamine metabolism into the TCA cycle. Supplementing beta-hydroxybutyrate did not promote the growth of any cell line, despite the expression of requisite transporters and enzymes. Beta-hydroxybutyrate contributed to metabolic flux into the TCA cycle for biomass and energy production; however, this pathway was significantly reduced in the glioblastoma cell line U-87 MG compared to the other cell lines. This finding suggests the potential efficacy of ketogenic diets as a treatment option for glioblastoma patients, providing additional energy substrates for normal cell metabolism. Furthermore, the U-87 MG cell line exhibited overexpression of the mitochondrial uncoupling protein UCP2 and distinct morphological changes in mitochondria, indicating a potential link between these factors and the reduced utilisation of beta-hydroxybutyrate through the TCA cycle. Further investigation is warranted to elucidate this relationship fully. Part B investigated the efflux of amyloid-beta peptides out of cells. Deposition of amyloid-beta peptides is one of the hallmarks of Alzheimer's disease and it may relate to an impaired clearance pathway with a critical actor: P-glycoprotein. This investigation focused on the organismal level and used C. elegans as a model organism for measuring behavioural effects. The expectation was to elucidate whether P-glycoprotein could be a target in the prevention of Alzheimer's disease. Alzheimer's disease poses a growing concern to society, particularly with the aging population. Current understanding implicates abnormal accumulation of amyloid-beta peptides as a key factor in its pathogenesis, potentially leading to neuronal dysfunction. Our observation indicated that the presence of amyloid-beta aggregates in the body wall muscles or somatic nervous system correlated with impaired locomotion, neuromuscular functions, and a shortened lifespan in C. elegans. A C. elegans strain with human P-glycoprotein expression in body wall muscles was made and used to generate a hybrid strain expressing both amyloid-beta and human P-glycoprotein. The expression of human P-glycoprotein in C. elegans caused paralysis and compromised neuromuclular functions in the worms, but the lifespan was unaffected. Although human P-glycoprotein expression did not reduce the accumulation of amyloid-beta peptides in worms, it restored locomotion compared to parental strains expressing amyloid-beta or human P-glycoprotein alone. The restoration of locomotion did not translate into improvements in neuromuscular function or lifespan. The results suggest that targeting the P-glycoprotein-mediated clearance pathway holds promise for preventing Alzheimer's disease. However, it also highlights the complexity of the clearance pathway, indicating that multiple components may be considered for effective therapeutic strategy.Item Restricted Naphthyridine-derived bimetallic phosphinite and metallophosphorane complexes(2024) Delaney, AndieThe studies presented here concern the synthesis and reactivity of bimetallic phosphinite and metallophosphorane complexes. Much of the work presented is on the synthesis of bimetallic complexes using new dinucleating ligands, sometimes using a dehydrohalogenation methodology that has not yet seen much use in the synthesis of bimetallic complexes. The synthesis of Group 10 and 11 metal complexes are presented, with a major focus on the reactivity and catalytic potential of bimetallic complexes of nickel and palladium. Dinucleating "expanded pincer" ligands have previously been used to isolate bimetallic complexes. To add to this body of literature, the first publication presents the synthesis of bimetallic gold(I), silver(I) and copper(I) complexes of the tBuPONNOP ligand, a new expanded pincer ligand based on a 2,7-diphosphinite-substituted-1,8-naphthyridine backbone. A range of coordination modes were observed, with the geometric preference of the transition metal determining if it binds through P,N-, P,P- or P-only coordination modes. However, the low-yielding synthesis of the tBuPONNOP ligand hampered further research into this ligand. The second publication studies the tendency of the tBuPONNOP ligand to rearrange in the presence of NiBr2, which was observed previously for iPrPONNOP. However, a new rearrangement product was accessible with tBuPONNOP; the bimetallic metallophosphorane complex Ni2Br2(tBuPONNOPONNO), which featured formation of a new P-O bond to give a diphosphoranide ligand. Phosphoranides have not previously been incorporated into dinucleating ligand frameworks. New precursors, PONNHO, were developed to access PONNOPONNO products more easily, but the tBuPONNHO and iPrPONNHO precursors were found to give different product distributions. The dinickel(II) complexes Ni2Br2(PONNOPONNO) could be reduced to form highly planar dinickel(I) species, Ni2(PONNOPONNO), which have a direct Ni-Ni bond. While elementary reaction steps are well-understood for monometallic systems, there have been less studies on how bimetallic complexes perform these transformations. The third publication focuses on the reactivity of Ni2(tBuPONNOPONNO) with alkyl halides in order to explore elementary steps. Oxidative addition occurs across the Ni-Ni bond to form species of the type Ni2(R)(X)(tBuPONNOPONNO). However, the ethyl-bridged species are unstable in solution, undergoing beta-hydride elimination to form ethene and Ni2(H)(X)(tBuPONNOPONNO). DFT studies were used to examine the mechanism of beta-hydride elimination, representing one of few mechanistic studies into this step for dinuclear complexes. The macrocyclic structure of the ligand was found to have a major impact on the rate of beta-hydride elimination, with the bending of the backbone in the absence of a coordinating anion reducing the rate by relieving steric pressure on the bridging ethyl ligand. Unpublished reactivity studies are discussed to show the difficulty in understanding the mechanism of oxidative addition to Ni2(tBuPONNOPONNO). The fourth publication explores the use of PONNHO ligands to access bimetallic palladium and platinum complexes via dehydrohalogenation. In this case, monometallic MCl2(PONNHO) complexes could be isolated, which were not observed during studies with nickel. Addition of a base to MCl2(tBuPONNHO) gave bimetallic species of the type M2Cl2(tBuPONNO)2, and these M(II)2 complexes could be reduced to give species with Pd(I)-Pd(I) and Pt(I)-Pt(I) bonds of the form M2(tBuPONNO)2. Interestingly, the macrocyclic diphosphoranide PONNOPONNO ligand does not form when using Pd or Pt precursors. Instead, a weak P-O interaction, of which there have been few reports for transition metal complexes, is apparent from solid-state and solution-state data of M2(tBuPONNO)2. Finally, the catalytic potential of Ni2Br2(PONNOPONNO) and Pd2Cl2(tBuPONNO)2 in cross-coupling was examined. These studies are ongoing.Item Embargo Psi controls signalling from the Drosophila cortex glial niche to regulate neural stem cell fate(2024) Muckle, DamienGlioma patients experience high rates of morbidity and invariable fatality, yet no new, effective treatments have emerged in more than 35 years. Progress in therapeutic development is hindered by a limited understanding of the biology of these heterogeneous brain tumours, which are driven by glioma stem cells supported by a glial niche. Genomic sequencing of the low-grade brain tumour oligodendroglioma identified frequent loss-of-function mutations in the single-stranded DNA/RNA binding protein FUBP1, which are predicted to drive these tumours. However, functional studies investigating FUBP1 function in mammalian systems are complicated by compensatory effects from paralogues within the FUBP protein family, which share common gene binding targets. In Drosophila, the three mammalian FUBP proteins are represented by a single orthologue, Psi, which shares high structural and functional similarity to FUBP1. By taking advantage of this reduced functional redundancy, and the powerful tractability of Drosophila genetics, we dissect FUBP1/Psi function in the cortex glial niche, which functions analogously to the oligodendroglioma niche by providing the structural support and secreted signals which regulate stem cell proliferation and differentiation. Here we demonstrate Psi knockdown specifically in the cortex glial niche of the Drosophila larval brain reduces cortex glial growth and proliferation. Moreover, cortex glial-specific Psi depletion cell non-autonomously drives the proliferation and expansion of otherwise wild-type NSCs. Thus, we present the first evidence that an FUBP family protein functions in a cell non-autonomous manner to control NSC fate. To determine the molecular basis for Psi's capacity to control NSC renewal and differentiation from the supporting cortex glial niche, we used Targeted DamID (TaDa) to identify direct, genome-wide Psi binding targets in cortex glia. We further identified differentially expressed and/or spliced targets via RNA sequencing of Psi-depleted cortex glia and associated NSCs compared with isogenic controls. Intersection of Psi binding targets and transcriptionally altered genes in Psi-depleted cortex glia revealed Psi directly regulates components of major developmental signalling pathways, Hippo and MAPK, among other networks essential for niche function. Our functional genetic studies indicate Psi represses upstream Hippo pathway components in the niche to maintain normal cortex glia growth and proliferation. Furthermore, Psi knockdown directly upregulates EGFR ligand spitz (spi) in cortex glia, which functions in the niche to cell-autonomously regulate cortex glia growth and proliferation. Psi depletion also upregulates another EGFR ligand, gurken (grk), which, in contrast to spi, is required to enable expansion and proliferation of neighbouring NSCs driven cell non-autonomously by loss of Psi. Together, our data demonstrate Psi functions cell non-autonomously in the glial niche to orchestrate signalling networks required to prevent excessive NSC renewal. Thus, given the high degree of functional homology with Psi, we predict FUBP1 loss-of-function drives oligodendroglioma tumourigenesis, at least in part, by dysregulating intra-tumour interactions between the glial niche and glioma stem cells.Item Embargo International politics and construction of climate security by small island developing states: Maldives and Samoa form broader meanings of security(2024) Rasheed, AthaullaThis research investigates Small Island Developing States' (SIDS) discursive formation of national and foreign policy narratives on climate change as a security concern. It recognises SIDS have played an important role in promoting comprehensive approaches to climate security at the United Nations Security Council debates - these included considering multi-sectoral climate-related threat factors and comprehensive security provisions, including collaborative (whole-of-government) governance approaches to address them. For this thesis, climate security is defined as the ability of states or communities to address and build resilience against climate change in achieving sustainable development, self-sufficiency, and national security. Although it recognising SIDS' engagements in the Security Council debates, the main objective of this thesis is not to analyse their international (climate security) narratives, but instead to present an analytical framework to investigate and portray a domestic construction of climate security by SIDS - using the Maldives' and Samoa's experience - and to explain the domestic narratives driving these countries' national and foreign policy on climate change as a security issue. This thesis asserts that domestic construction helps to make better sense of why SIDS' claim for broader meanings of security becomes important for the Security Council's climate debates, or securitising climate at the international level, and why a comprehensive approach to problem-solving is important in addressing the impacts of climate change on national and international peace and security. In this respect, in adopting a constructivist approach to international relations and security studies, this thesis identifies, analyses, and explains the discourses and identities constitutive of policy narratives that have shaped the climate threat identification and problem-solving approaches adopted in Maldives and Samoa. This thesis analyses the formation of climate policy as a national crisis, threat categories impacting the countries' capacity to achieve sustainable development, and the meaning of security in their island contexts concerning those threats. In that, the intersubjective aspect of the discursive formation of identities and interests explains the interconnectedness or constitutive function of domestic and international policy narratives of states. The domestic interests associated with policy narratives concerning the security implications of climate change can explain both their national and foreign policy drivers. This thesis concludes that the Maldives' and Samoa's cases assert that SIDS become important stakeholders in developing intersubjective narratives to incorporate more holistic and comprehensive aspects of problem-solving into the international peace and security discourse concerning climate change. The Maldives' and Samoa's policy discourses and identities forming climate security narratives, analysed in this thesis, provide a practical framework to explain this.Item Embargo Appropriately Timing Seed Germination- New Players and Upstream Controllers(2024) Wellawatta Mudiyanselage, AyeshaSeed germination is a most critical developmental phase change, particularly under abiotic stress conditions such as drought or salinity. The timing of germination plays a major role in setting the timeline of the plant developmental cycle, and in conditioning seedling survival and adaption to unfavourable environments until completion of the plant developmental cycle and successful reproduction. Over recent decades, great progress has been made in understanding seed dormancy, its establishment during maturation on the mother plant, and the factors controlling its release after shedding. In contrast, little is known about the genetic determinants of germination in non-dormant seeds, especially under abiotic stresses. The Arabidopsis ERECTA family AtERf is demonstrated master regulator of various aspects of aerial plant growth and development, and is also involved in responses to environmental stresses, and some immune responses. A recent study (Nanda et al., 2019) uncovered another, unsuspected function, especially in the sensitivity of seed germination to salinity and osmotic stress. The germination of seeds with reduced ERECTA family signalling was found to slowed down, delayed or even halted by salinity and osmotic stress, through largely reversible mechanisms, so that when conditions became more favourable again, germination generally resumed, without significant loss of seed viability. That adaptive function was shown to be primarily under maternal control, and to involve the three family members, with specificity, among ERf members. The present study followed from that work, with a two-fold aim: a) Better understand the physiological and molecular bases of the maternal inheritance of the ERf-mediated germination phenotype; b) Test conservation across species of the newly discovered ERf regulatory function in Arabidopsis seed germination, with a focus on barley (Hordeum vulgare, Hv), a major staple food and pillar of the brewing industry. The first Chapter of this thesis describes the discovery of a novel molecular interactor of the Arabidopsis AtERf - the MYB family transcription factor AtGL1- previously unknown to be acting in seeds, nor to interact with the extensively documented ERf signalling pathways in aerial organs. GL1 is here shown to synergistically interact with the ERf members, in a gene combination-dependent manner, to regulate the initiation, progression, and timing of germination completion under saline conditions. A second Chapter reports on a genome-wide analysis of ERf- and GL1-mediated changes in transcriptional networks during early seed development and differentiation through RNAseq analysis of developing siliques. The results indicate that wide-spread ERf and GL1 separately act and also interact in the transcriptional control of hormone signalling, transcription factors, cell wall biogenesis, the formation of cuticular and wax compounds, stress response pathways. The last part of the thesis presents the analysis of a range of barley mutant lines obtained through CRISPR-Cas9 editing of the putative barley HvERf and HvGL1 orthologues. They show that these genes, separately and together, exert a major regulatory role in vegetative development, fertility and the anatomical and structural characteristics of the maternal seed enclosing tissues, and in the regulation of seed germination under salinity but also constitutively. In conclusion, the findings reported in this thesis overall highlight the potential of the barley ERECTA genes and putative orthologue to AtGL1 for genetic improvement, especially with respect of more uniform germination within seed cohorts, and regulation of its timing to mitigate risks of germination failure or seedling death, thus enhancing yield.Item Embargo A Change In The Field: Australia-India cricket and the possibilities for cultural openness in the shadow of colonialism(2024) Piggott, GeoffreyA common view in the discourse of Australia-India cultural relations is that for a more meaningful relationship to develop, Australia must move beyond approaching India through the prism of practices which have their roots in the two countries' shared - but contrasting - history of British colonialism. Cricket, it is often said, provides a shallow point of connection and acts as a reminder of the racial and cultural injustices of Empire. This thesis problematises such received wisdom. It begins from the premise that while there is little doubt that a colonial lens limits Australian understandings of India, cricket continues to be a major point of popular cultural contact between the two countries, and has, in the last three decades, moved beyond the colonial power dynamics of its past as India has become the pre-eminent force in the sport. In light of this, this thesis asks how and to what extent cricket might move Australia-India cultural relations beyond their mediation through the echoes of the British Empire and foster a disposition of greater cultural openness from Australia towards India. It presents a detailed study of media representations and in-depth interviews with commentators, journalists, administrators and players, examining how India's rise to power in cricket was negotiated in Australia. Through analysis of a series of ruptures in the sport during the late 1990s and early 2000s, the thesis charts how long-maintained Australian narratives of Indian racial and cultural inferiority were rendered unsustainable by India's exercise of its newfound power. This was due, I argue, partly to the specificities of sport as a cultural field, its lusory nature providing space for changes in Australian attitudes, and partly to the impact, in Bourdieuan terms, of the economic field on the cultural, with India's economic power changing fundamental aspects of the form of the sport. The shift in cultural power opened new possibilities and posed still unresolved challenges for Australian cricket and the broader Australia-India cultural relationship. On one hand, the period of conflict, ironically, established a site of nostalgic memory which now provides a meaningful point of connection between the two countries. On the other hand, the changes in the form of the game mean that cricketing traditions which have positioned it as part of the Australian national imaginary are threatened, and that the financial health of the sport is tied to a hyper-commercial and increasingly politicised Indian cricket establishment. Through my research, in addition to adding to the discourse of Australia-India relations, I add to contemporary debate in cultural studies and postcolonial studies. I propose that, for all the game's colonial history and contemporary neo-liberal capitalist logic, the changes in cricket are an example of how formerly colonial cultural practices can, in complex and imperfect ways, move beyond their racially hierarchical histories, act as a shared point of reference across national-cultural boundaries and provide a site for the development of attitudes of cultural openness.Item Embargo Additive Manufacturing Based on Electrochemistry(2024) Viktorova, JekaterinaA fabrication method combining 3D printing and multi-material electrodeposition is introduced in this thesis. The method combines electrochemical and three-dimensional control of electrode positions to culminate in a new process for 2D patterning and the 3D printing of metals, semiconductors, as well as polymers into complex shapes with feature sizes as small as 10 um. The method specifically allows access to patterned or printed, previously difficult-to-process electrically conductive pi-conjugated polymers. The technique uses electrodes in a solution of an electrodepositable material to perform electrochemical printing, a process that can be controlled by varying the inter-electrode gap, the applied potential or current, the electrode geometry and dimension, the electrodeposition solution (ink), movement direction, and movement speed. The first chapter introduces the concepts of electrodeposition and localized electrodeposition and applies them to electrochemical printing. It also explores the influence of the different parameters which affect the printing process and introduces the types of materials that can be printed using this method. In Chapter 2, electrochemical printing is shown to have a unique combination of speed and resolution, multi-material printing, and morphology control, culminating in multi-material device fabrication. In Chapter 3, the first steps are made in monitoring the electrochemical reactions and localized deposition processes in-situ by combining electrochemical analytical methods such as cyclic voltammetry and chronoamperometry with electrochemical quartz crystal microgravimetry. Using poly(3,4-ethylenedioxythiophene) (PEDOT) as a model system, we study the effects that the composition of the supporting electrolyte and solvent used, de-oxygenation and monomer concentration had on the polymerization yield. In Chapter 4, a brand-new approach involving the ferrocene-mediated cationic electrochemical printing of bisphenol A diglycidyl ether and tris[4-hydroxyphenyl] methane triglycidyl ether) based on electrochemically controlled ring-opening polymerization is demonstrated. The development of this novel fabrication method combining 3D printing and multi-material electrodeposition opens new pathways for advanced material design and manufacturing. By enabling precise, controlled deposition of metals, semiconductors, and conductive polymers in complex 2D and 3D architectures, this technique can significantly enhance applications in fields such as flexible electronics, biosensors, and energy storage devices. The ability to pattern previously hard-to-process conductive polymers also presents opportunities for innovations in organic electronics and optoelectronic devices. The versatility and scalability of this method position it as a promising platform for future research and development in multi-material printing and electrochemical manufacturing, potentially unlocking the production of functional materials and devices.Item Embargo Characterisation of the Transcriptome and Proteome of Residual Bodies and Uncovering of a Non-Canonical Role of the Histone Variant H2A.B3 During Spermatogenesis(2024) Apu, NazmulSpermatogenesis is a process where male germ cells undergo morphological changes to become motile and fertile spermatozoa. Key changes include the shrinkage of the nucleus, development of the flagellum, and extrusion of most cytoplasmic contents into the lumen of the seminiferous tubules in the form of Residual Bodies (RBs). Conventionally, RBs were thought to be phagocytosed by Sertoli cells (SCs). However, recent evidence challenges this view, highlighting a more intricate utilisation of RB contents. Specifically, H2A.B3, a spermatid-specific histone variant known for its positive regulation of germ cell transcription, is preserved in a full-length non-chromatin-bound form within RBs. Remarkably, upon RB absorption, H2A.B3 is detected in the nucleus of SCs. Intriguingly, the H2A.B3 KO mouse exhibits tubules congested with the cytoplasmic content of maturing spermatids and defective SC phenotypes. This suggests a novel epigenetic information transfer mechanism between germ and Sertoli cells mediated by RBs, where H2A.B3 potentially acts as a chaperone to transport germ cell-specific factors to SCs. The first aim of the thesis was to establish an improved purification method for RBs from mouse seminiferous tubules. Chapter 3 introduces a continuous sucrose gradient ultracentrifugation-based method, enabling the isolation of up to 98% pure RBs from only 1 g of testis tissue. Morphological characterisation of RBs using RB-specific EMA staining and transmission electron microscopy (TEM) revealed that the tubules of H2A.B3 KO mice contain a more dispersed form of RBs with a different size distribution, suggesting delayed RB absorption by SCs and slower tubule differentiation. Furthermore, H2A.B3 KO RBs demonstrated more filled vacuoles of lysosomal nature compared to WT, implying defects in lysosomal clearance. The second aim, explored in Chapters 4 and 5, was to comprehensively characterise the transcriptome and proteome of RBs, respectively. Using Nanopore RNA-sequencing (RNA-seq), diverse classes of biologically important RNA were identified in RBs, with a significant overrepresentation of replication-dependent histone genes in H2A.B3 KO RBs. This implies a defective chromatin compaction process, as evidenced by a higher sperm chromatin density in H2A.B3 KO mice. Additionally, H2A.B3 was found to be involved in splicing, showing a preference for first and last exon inclusion. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) proteomic study of RBs detected 3,226 proteins, which are mainly involved in protein transport and metabolism. Our investigation also reported the presence several histone proteins in RBs for the first time. Moreover, RBs contain nine unique H2A.B3-interacting proteins, the majority of which are associated with splicing. The third aim of the thesis, explored in Chapter 6, was to investigate the role of H2A.B3 in RNA degradation. A newly developed bioinformatic pipeline was used to measure and compare the 3'- and 5'-end degradation levels of replication-dependent histone mRNA transcripts between WT and H2A.B3 KO across various spermatid stages and RBs. The 3'-end of replication-dependent histone mRNAs was the most degraded in early-round spermatids of H2A.B3 KO mice, whereas the 5'-end remained mostly unaffected, which was also validated by overexpressing the H2A.B3 protein in Neuro2a cells. In summary, this thesis presents a modernised RB purification method, aiding in understanding RB biology and the crucial roles played by H2A.B3. The findings lay the groundwork for investigating broader hypothesis regarding epigenetic information transfer between germ cells and SCs via RBs. Additionally, a novel non-canonical role of H2A.B3 in the degradation process of replication-dependent histone mRNA is uncovered, further expanding our understanding of spermatogenesis.Item Embargo In Situ Oxygen Isotopes and Water Concentrations: Analytical Developments and Applications to Extraterrestrial Materials(2024) Patkar, AdityaO-isotopes of chondrules, CAIs, and matrix commonly show variable 16O abundances. A 16O-poor aqueous or water-ice reservoir is thought to have influenced their primary isotope ratios. This study explores the interrelationship between O-isotope systematics and total water contents (H+OH+H2O) in components from carbonaceous chondrites, pallasites and asteroid Ryugu samples using the SHRIMP SI ion microprobe. Analytical development is needed to measure in situ water in meteoritic NAMs, and three O-isotopes in the hydrated chondrite matrix because of the presence of a large 16O1H peak. Techniques were developed to reduce instrument water background and reliably measure water content <100 ppm, employing various sample preparation methods and introducing a Bi-Sn alloy as an alternative to In mounts. Terrestrial minerals with varying water contents were used to quantify the tailing from 16O1H under the 17O peak. Minerals show D17O residuals systematically related to the 16O1H peaks suggesting consistent tailing, and a tailing correction has been proposed. Thirdly, IMF bias was determined in a suite of olivine reference materials over the entire Mg/Fe compositional range. CC chondrules show variable O-isotope ratios with most type I olivine (Mg#>90) are isotopically lighter reflecting reducing conditions, higher T, and lower dust:gas, whereas type II olivine (Mg#<90) that formed in an oxidising, dust-rich environment are isotopically heavier. In contrast to previous studies in chondrule NAMs with a large range of ~8 ppm to ~1 wt% water, our results in >250 olivine grains from chondrules and isolated matrix grains are much lower. Similar to O-isotope dichotomy, forsterites (Mg# >98) from CM, CO, CV chondrites contain a median of 4.6 +- 3.7 (1SD) ppm water, while type II olivine (4450 permil. However, CAI phases from CV finds show several 1000s of ppm water, potentially originating from small fractures that pervade the CAIs, especially melilite, suggesting terrestrial alteration. Lower water in clean regions of melilite from CV chondrite finds and in the rejected spots from Allende CAIs that overlap fractures suggests that the fractures from CV finds may contain localised incipient hydrated products. The low water data in Allende CAI phases suggests a nebular origin and similar P-T conditions which is consistent with our current understanding of CAI formation and evolution. Hydrated matrix from CM, CI, CY chondrites and asteroid Ryugu reflects extensive aqueous alteration. Bulk O-isotope ratios in the hydrated matrix dominated by serpentine-saponite show large IMF effects likely controlled by Mg/Fe variations. Bulk CM2 matrix shows D17O values ranging from -1.6 to -2.5 permil compared to whole-rock values which range between -2 to -4 permil. In contrast, matrix from CI and CY chondrites and Ryugu shows a D17O range overlapping with the whole-rock values. The large D17O scatter can be partly attributed to uncertainty in tailing correction but also possibly reflects the intrinsic isotopic heterogeneity of the chondritic matrix.Item Embargo Wild Goose Tracks in the Snow: An Illustrated Record of my Preordained Life by Wanyan Linqing (1791-1846): a nineteenth-century memoir(2024) Sanderson, ChristinaWanyan Linqing (1791-1846) was a Manchu Bannerman who travelled throughout China as an official in service of the Qing Court. In his later years he acquired and moved into a renowned garden-mansion in Peking, where he composed an autobiographical memoir in classical Chinese, Hongxue yinyuan tuji (Wild Goose Tracks in the Snow: An Illustrated Record of my Preordained Life), recording, in two hundred and forty chapters each accompanied by a woodblock illustration, as many moments of his life deemed to have been the most memorable. During the 1980s, the first one hundred and seventy chapters of this memoir were translated and annotated in Hong Kong by Mongol Bannerman Professor Yang Tsung-han (1901-1992). Under the guidance of Professor John Minford, Christina Sanderson has recently compiled the first complete translation and annotation of this work, by editing Yang's existing translation and commentary and translating and annotating the final seventy chapters. This thesis is a reflection on that memoir, and on the process of its translation. It argues that Tracks in the Snow is a remarkable window into the world of traditional China. To prove this, it presents several different ways of reading the memoir, including from a biographical and historical perspective, and in the context of literature.Item Embargo Road from Rebetiko: Explorations in the Fusion of Jazz and Traditional Greek Urban Music(2024) Campbell, Constantine RobertThis project is a research-led hybridity experiment in creative practice, fusing jazz and Greek rebetiko. The thesis explores the history and nature of jazz fusion - or hybridity - with a view to understand its significance for the genre of jazz and to position the rebetiko-jazz fusion experiment within it. The thesis also explores the history and nature of Greek rebetiko music in order to pay homage to its traditions, heritage, and musicians, and to embrace its spirit and learn from its mechanisms for the purpose of hybridity. Finally, the thesis offers an exegesis of creative practice, which describes the inspiration, methods, processes, and outcomes of this rebetiko-jazz fusion experiment, which culminates in twelve original compositions that have been performed and recorded across two albums. I conclude that my creative practice is a glocalised expression of both jazz and rebetiko.Item Embargo Quantifying porphyry copper deposit fertility from zircon geochemistry using predictive modelling: from theory to applications(2024) Carrasco Godoy, CarlosThe demand for copper in the next 20 years is expected to be equal to its total historic production due to copper's fundamental role in the transition to green energy. Porphyry copper deposits are the source of 75% of the world's copper but the rate of discovery of new deposits has declined over the last decade. Zircon is an accessory mineral that is resistant to chemical weathering and physical abrasion. It is common in siliceous igneous rocks, including those associated with porphyry copper deposits. Zircon's chemical composition can provide information about the magma it crystallizes from and potentially be used to distinguish ore-forming porphyry magmas from barren magma systems. This thesis covers three projects aimed at understanding how zircon geochemistry can be used in porphyry Cu exploration. The first presents an empirical method, based on Onuma diagrams and the lattice strain theory, to calculate missing rare earth elements (REE) and Y data in legacy datasets in which some elements were not analysed. The results have been calibrated against known concentrations, and lattice strain theory estimates, using a dataset of ~1,500 zircons with no missing REE + Y concentrations. The results show that REEs can be confidently imputed with as few as five REEs and allow the estimation of La, Pr and Ce* in zircons with greater confidence than traditional methods. These methods enable the reconciliation of old and new REE + Y data. The second project is a data-driven analysis of zircon geochemistry that compares those that formed in magmas associated with porphyry copper deposits with those that formed in barren magmatism. This study compiles a database of more than 23,000 zircons from > 30 porphyry copper deposits, barren sources and rivers and uses machine learning for classification and comparison with traditional geochemical thresholds. The study confirms some of the zircon fertility indicators proposed in the literature (Eu/Eu*, Dy/Yb, Ce/Nd), discard those that are not diagnostic (Hf, Th/U), and proposes two new fertility indicators (P and shape of the REE pattern). It also shows that random forest models outperform traditional geochemical methods by correctly identifying up to 20% more fertile zircons. Shallow machine learning algorithms outperform the traditional geochemical discriminators and provide insights into characteristics that have not previously been considered when evaluating porphyry copper fertility using zircon geochemistry. The last project is a test case of zircon fertility classification using random forest in the world's most prolific porphyry copper region: the Loa River drainage basin, Northern Chile, that includes the Chuquicamata, El Abra, Collahuasi, Spence and Sierra Gorda porphyry districts. Nearly 1,600 zircon grains, collected along the Loa River basin, were analysed for trace elements, geochronology, and their class membership probability (fertile or barren) calculated using predictive models. The results indicate that periods with higher zircon frequency coincide with the ages of the magmatic arcs in the area. Furthermore, the age of the deposits matches the end of these periods and is accompanied by an increase in the number of zircons classified as fertile. There is also an increase in the fraction of fertile zircons in samples collected close to deposits, which reach their maximum near the El Abra deposit.Item Embargo White Fantasy, Indigenous Sovereignty: Tools for an Ethics of Representation in Settler-Colonial Creative Writing Practice(2024) Stevens, Rosanna"White is a colour. A page is not a neutral cultural object. The white imagination is indeed colour blind. It is blind to its own colour - whiteness; and to its own cultural standpoint that is neither neutral nor universal." - Jeanine Leane (2021, para. 26) First Nations scholars and writers have spent considerable time and thought critiquing mainstream methods with which white Australian writers tell stories about Aboriginal and Torres Strait Islander Peoples, issues, culture and Country. While some white settler-colonial writers and scholars have responded to the authority of First Nations knowledge holders and makers, the uptake of Indigenous instruction in wider settler-colonial creative discourse remains limited. Nonetheless, white desire to tell stories that 'get it right' in representing Indigeneity has remained and intensified in anxiety, without significant questioning among white writers about what 'getting it right' is, who determines this achievement, whom it serves, and what that means. In this thesis, I present how I have used my creative practice and positionality as a white colonial-settler middle-class woman, to participate in this questioning. This PhD project articulates how attempts at representing First Peoples become political projects as I see and understand myself, my concerns, my creative practice and my words in the context of colonising racial categories, and the insistence and values of unceded Indigenous sovereignty. As a result of this questioning - guided by critical race and whiteness studies, Indigenous-led literary and knowledge production studies, and phenomenological cultural studies - I develop five conceptual tools that decentre the goal of representational perfection of Indigenous subjects from white subjectivity, on the grounds that this is a false, and colonising, project. Instead, these conceptual tools - of unfinishedness, apology, honesty, contextualisation and turning - support a practical, lived redefinition of what it means to be a writer who is accountable to those with a vested interest in a story. This thesis contributes to understanding how, in the context of Indigenous sovereignty, settler-colonial storytellers might realise and loosen the tight grip of normative narrative production that encourages a closed, hurried, and possessive creative and representational practice.Item Embargo Exercise of adaptive leadership by senior officials in the Australian Public Service as a Westminster institution(2024) McMahon, RobertFramed by tensions between Westminster conventions and traditions, and public servants' values, craft obligations and felt responsibility, the research explores how Senior Executive Service (SES) officers in the Australian federal government make use of a specific leadership model, adaptive leadership (AL), in conceiving and performing their roles. The kernel for the study is that AL, adopted by the Australian Public Service Commission in 2012 to develop its SES cadre, evinces particular entrepreneurial characteristics which may not be a natural fit in the Australian Public Service (APS) as a derived Westminster institution with inherited conventions, traditions and understandings. While traditional formulations posit that Westminster public services operate along dichotomous responsibility-accountability conventions and principal-agency relationships, these accounts fail to sufficiently acquit the role of the public service in an increasingly complex environment. Conceptually, this study explores the role of the public service as an institution with a form of independence adapting to changing responsibility and dispersed accountability, including an increased relationship between senior officials direct to the parliament. Empirically, the study examines subsidiary questions about how, and in what circumstances, public officials exercise AL, and whether they do so in modified forms depending upon organisational setting. Emerging from this exploration was a distinct set of leadership conditions -- a 'native' leadership craft -- used by SES officers to make sense of and navigate their environment: a "habit of discernment" to bridge knowing the right thing to do and acting to do it. To explore for the prevalence of AL against the normative backdrop of the APS's role in the Westminster tradition, the research employs a mixed methods approach involving interviews with dozens of elite (political and administrative) actors, APS SES officers and observer-stakeholders; grounded in three organisation-level case studies to observe the possible situational variation of AL. It also draws on a large bank of primary and secondary documentary material--speeches, press releases, parliamentary debates, reports, guidelines, monographs and journal articles. This research is relevant conceptually and timely in practice. Along with other nations, Australia faces a set of difficult challenges ahead, not least managing the social and economic aftermath of historic pandemic crisis, extant international strategic and economic pressures, and domestic policy challenges. Effective leadership by senior officials will therefore be critical to navigate these pressures. In light of the research findings, the study proposes changes in SES leadership development policy and practices to support senior officials navigate their evolving environment.Item Embargo The role of TREX-2 complex in nucleo-cytoplasmic mRNA exportKim, YoonaEukaryotic cells display compartmentalisation within the nucleus and cytoplasm, regulated by nucleo-cytoplasmic transport (NCT). This process is essential for the movement of functional molecules, with the nuclear pore complex (NPC) acting as a selective barrier. While the karyopherin family oversees the transport of most macromolecules, mRNA export follows a distinct route mediated by Mex67-Nxt1 in S. pombe and Nxf1-Nxt1 in humans, recognised as the sole mRNA export receptors with evolutionary conservation. Although current models propose the recruitment of Transcription and Export complexes 1 and 2 (TREX-1 and TREX-2) to mRNAs during transcription elongation, delivering them to the Mex67-Nxt1/NXF1-NXT1 transport receptor, the non-essential nature of Mex67 and Nxt1 genes in S. pombe suggests the existence of alternative mRNA export receptors. In this study, we discovered the intriguing role of the TREX-2 complex as an mRNA export receptor, facilitating the transit of mRNAs through the nucleopore channel. Our results demonstrate that the TREX-2 complex functions as an mRNA export receptor, despite its anchorage to the nucleoplasmic side of the NPC via the extended C-terminal domain of the Sac3 subunit, known as GANP in humans. Our research revealed that the TREX-2's head-domain, consisting of the N-region with FG-like repeats and the mRNA-binding M-region, can extend to the cytoplasmic side of the NPC. Furthermore, we demonstrated a strong correlation between the head-domain of TREX-2 complex and messenger ribonucleoproteins (mRNPs) during nuclear translocation, independent of Mex67. The research posits a dynamic model in which the TREX-2 complex and mRNPs move conjointly through the NPC's FG-repeat framework. While this coordinated migration occurs, the TREX-2's tail-domain is consistently anchored to the nuclear side, signifying an existence of a distinctive pathway for the nuclear export of mRNA, one that does not solely depend on the traditional transport receptor Mex67-Nxt1 (NXF1-NXT1 in human). Furthermore, we explored the functional role of a newly identified protein complex, namely the Sac32-Pci2-Dss1 complex. Our findings indicate that Sac32 shares conserved homology with Sac3, similar to the Sac3 subunit of TREX-2 complex, and its structural arrangement is preserved across a range of eukaryotes from S. pombe to higher organisms. Our investigation revealed that Sac32 predominantly localises in the nucleoplasm, in contrast to TREX-2 complex, which is situated at the nuclear periphery. The deletion of sac32 and pci2 resulted in the accumulation of mRNA within the nucleus, indicating that the Sac32-Pci2-Dss1 complex may function as a mobile version of the spTREX-2 complex, contributing to the mRNA export. Remarkably, our observations indicate that Sac32 is capable of migrating towards the nuclear periphery where it potentially interacts closely with the head-domain of the TREX-2 complex. This suggests a role for Sac32 in facilitating the transfer of mRNPs to the TREX-2 complex for nuclear mRNA export. Finally, our extensive genome-wide analyses revealed that TREX-2 complex binds to mRNAs globally, while TREX-1 complex exhibits both global and selective interactions with mRNA molecules. Additionally, our findings suggest the potential involvement of Sac32 in co-transcriptional mRNA processes. Our study presents the 'lasso model' where the TREX-2 complex is essential for bulk mRNA export, engaging after mRNPs dock at the nuclear basket facilitated by nuclear export factors like TREX-1 complex, Sac32-Pci2-Dss1 complex, or Mex67-Nxt1. The TREX-2's head-domain actively transports mRNPs to the cytoplasm, while the tail-domain remains fixed at the nuclear basket. Our findings introduce a new paradigm for mRNA export, challenging the traditional view of the only mRNA export receptor and revealing a previously uncharacterised transport pathway within the NCT system that operates independently of established shuttle proteins.Item Embargo YAP activation in the skin promotes an inflamed and immunosuppressed microenvironmentGarrett, JessicaThe success of cancer immunotherapy is highly dependent on the tumour microenvironment. Tumour responsiveness to immune checkpoint inhibitors depends on potentiating cytotoxic T cell activity, but this can be blocked by the presence of immunosuppressive cells in the microenvironment which interfere with normal T cell function. Understanding how to combat immunosuppression and resensitise tumours to immunotherapy, is the focus of current research efforts. The oncogene Yes Associated Protein (YAP) has a well-established role in cancer growth and metastasis. Separate to cancer, there is an emerging role for YAP in the development of chronic inflammatory diseases and fibrosis. Given this, I sought to define the cellular and molecular immune responses driven by YAP hyperactivation in the skin, with the intention of understanding how oncogenic YAP might influence the tumour microenvironment. Two mouse models were characterised, where YAP was constitutively activated in the basal keratinocytes of the epidermis (K5>YAP5SA and K5>Lats1/2-/-). YAP activation resulted in keratinocyte hyperproliferation, thickening of the epidermis and the development of a dermatitis-like skin phenotype. Analysis of the skin immune contexture, facilitated by Flow Cytometry and single cell RNAseq, revealed a strong infiltration of myeloid cells (dominated by neutrophils), with a gene expression profile characteristic of myeloid derived suppressor cells. In the lymphoid compartment, CD4+ T cells and NK+ cells were significantly increased in YAP-activated skin, without a corresponding increase in cytotoxic CD8+ T cells. Infiltrating CD4+ T cell populations included both conventional, helper and immunosuppressive Treg subtypes. Corresponding analyte analysis, performed on plasma from both YAP-activated models, revealed a cytokine profile characteristic of chronic inflammation and immunosuppression. Importantly, in vivo growth of a syngeneic murine melanoma cell line was significantly accelerated when implanted in K5>YAP5SA mice. Taken together, these data identify a non-cell autonomous role for YAP in influencing the immune contexture of the skin, marked by features of cellular and molecular immunosuppression. Furthermore, the protumorigenic potential of the YAP-driven immune contexture, identified here, warrants further investigation in the immune-oncology space.Item Embargo Advanced Luminescence-Based Characterization Techniques For Perovskite Solar CellsBui, AnhThis thesis focuses on the comprehensive characterization of hybrid organic-inorganic perovskite-based solar cells (PSCs). Despite impressive advancements in perovskite-based solar cell research, resulting in certified power conversion efficiencies (PCE) of up to 26% for single-junction cells and 33.7% for monolithic perovskite-silicon tandem solar cells, further efforts are essential for commercializing this technology. A key challenge lies in the non-uniformity of the perovskite layer, which can serve as a degradation center during long-term operation and limit the device's original performance. To address this limitation, a series of novel characterization techniques based on photoluminescence (PL) imaging have been developed to spatially resolve crucial optoelectronic parameters, such as implied open-circuit voltage (iVoc), pseudo-fill factor (pFF), ideality factor (nid), and series resistance (Rs). The correlation between these parameters enables a profound understanding of device performance losses and their origins. In the first part of the thesis, we employ generalized Planck's law to convert the relative detected PL signal to quasi-Fermi level splitting (QFLS), representing the implied open-circuit voltage. We calibrate the halogen lamp with known absolute intensity to accurately calculate the scaling factor (SF) accounting for the detected light fraction. Our approach is validated through various independent techniques, including lifetime-calibrated PL, spectrally resolved PL, and comparison with terminal Voc. We apply this method to spatially resolve iVoc of different devices, encompassing bare perovskite films, perovskite top cells, and silicon bottom cells of tandem perovskite-silicon solar cells. The VOC loss due to non-radiative recombination and energy band alignment is subsequently calculated, providing a vital target for the fabrication process. In the second part of the thesis, illumination intensity and temperature-dependent PL imaging are employed to extract various optoelectronic properties of PSCs, including pFF, nid, and activation energy of recombination (Ea). The pFF parameter, which represents the fill factor of the device without series resistance, is used to evaluate the potential PCE of PSCs, offering the second target for the fabrication process. The PL-based method's contactless advantage enables the study of different layers and fabrication processes' effects on device performance, providing valuable insights. nid and EA help predict major non-radiative recombination mechanisms, offering further understanding of the performance loss origins. Additionally, correlations between these parameters are investigated for devices before and after degradation tests. In the third part of the thesis, we investigate the PL intensity at different terminal voltages, including open-circuit, maximum power point, and short-circuit conditions, to calculate the PCE image and the series resistance (Rs) image. A strong correlation between PL quenching and PCE is observed, highlighting the significance of PL intensities in assessing device performance. However, a weak correlation is found between the PL image intensity under open-circuit conditions and the final PCE, emphasizing the risk of misinterpreting device performance based solely on PL intensities. Furthermore, we demonstrate the impact of voltage-dependent series resistance on device simulation accuracy, underscoring another crucial contribution of luminescence imaging to the perovskite solar cell technology's research and development.Item Embargo Power Centralisation and Economic Diversification: The Political Economy of Saudi Arabia Based on Vision 2030(2024) Alhumaidi, KhalidSince the oil boom in the 1970s, the strategic focus of the Kingdom of Saudi Arabia (KSA) has been firmly centred on the pursuit of economic diversification beyond oil. Despite recurring efforts since the 1970s, the Kingdom's diversification strategies exhibit a cyclical pattern, strengthening in response to declining oil prices and subsequently receding when oil prices rebound, raising questions about persistent challenges to diversification. Numerous views have been proposed to explain this dilemma; however, they tend to overlook a critical aspect: the complex nature of the Saudi regime's power structure. In January 2015, King Salman's accession to the throne, coupled with Crown Prince Mohammed bin Salman's ascendance as KSA's de facto ruler, marked a turning point, leading to the launch of Vision 2030, which aims to reduce the economy's dependence on oil. Since then, KSA has seen significant shifts in its economic, social, and political fabric under Vision 2030. This thesis investigates the impact of the Crown Prince's centralisation of power on the implementation of Vision 2030. This thesis is based on field research in KSA. The methodology encompassed a spectrum of data collection techniques, including over 100 interviews with ministers, government officials, members of the royal family, development advisors, academics, and citizens, coupled with the analysis of primary sources. This thesis argues that power centralisation under the Crown Prince has brought an end to state fragmentation, a trait that facilitated inefficiency within the Saudi bureaucracy for five decades. The subsequent implementation of Vision 2030 has spurred increased government efficiency and expedited economic diversification initiatives in the industrial, investment, tourism and entertainment sectors and in initiatives such as the Aramco initial public offering. On the other hand, the implementation of Vision 2030 is not without challenges. The long-standing influence of the rentier economy has complicated the swift implementation of Vision 2030, especially through inherited challenges such as public sector expansion and private sector fragility, while emerging challenges like the absence of a political framework, mega projects, and an undefined economic structure have also impeded implementation. By evaluating the historical context of economic diversification, this thesis examines the period from the post-2015 era until 2022. It argues that centralisation has facilitated bypassing bureaucratic hurdles and diminishing the influence of narrow interest groups. This significant change, essential for advancing the agenda of economic diversification under Vision 2030, marks a departure from the Kingdom's politics pre-2015. This thesis concludes that the Crown Prince's centralisation of power has positively influenced economic diversification efforts based on Vision 2030.