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Basalt alteration and its consequences
Full text linkMy thesis explores the geochemical consequences of basalt alteration in three distinct Earth
environments using reactive transport modelling coupled to geochemical analyses. The
weathering of basalt creates unique chemical environments that can drive carbonate mineral
precipitation and other secondary mineral formation. The extreme reactivity of basalt, with
very fast weathering rates relative to other surface rocks, means that there is great interest in
understanding the impact of basalt alteration on the chemistry and secondary mineralisation
of different environments. This thesis sets out to explore this.
First, I examine basalt alteration at the Earth’s surface in the context of an ultramafic
chromite-bearing ore body. Chromium is an environmental toxin in its oxidised state, Cr(VI),
due to its water solubility. In contrast, its reduced form, Cr(III), is both less toxic and less
soluble. During weathering, Cr(III) in chromite ore oxidises to Cr(VI). I investigate the
chromium contamination resulting from the weathering of the ultramafic ore body, particu-
larly assessing the extent to which microbially mediated iron reduction contributes reductants
to this system.
Secondly, I investigate basalt alteration at the mid-ocean ridge, where seawater convec-
tion induced by proximity to magma leads to the alteration of basalt through water-rock in-
teraction. I assess the consequences of this alteration for the global sulfur cycle; specifically
with respect to anhydrite, which precipitates directly from seawater upon heating. I explore
how past variations in ocean chemistry may have affected both the amount and the depth of
anhydrite precipitation and speculate on the ultimate fate of this precipitated anhydrite.
In the final chapter, I study basalt alteration in the context of enhanced rock weathering,
where basalt serves as a source of alkalinity and cations to facilitate soil carbonation when
used as an agricultural amendment. These investigations were conducted in laboratory-based
flow reactor experiments. Specifically, I explore how the incorporation of commonly avail-
able mineral products (slag and gypsum) mixed with basalt affects soil carbonation effi-
ciency, comparing these mixtures to the outcomes obtained when using basalt alone
Donor Experience and Satisfaction: A Cross-Sectional Survey of Australian Milk Donors.
Full text linkPasteurised donor human milk is a vital resource for vulnerable preterm infants. As demand continues to grow, the sustainability of milk banking services relies not only on recruiting donors but also on fostering positive donor experiences. Satisfied donors are more likely to contribute consistently and advocate for the service, enhancing its visibility and community support. A total of 588 formal milk bank donors who donated to Australian Red Cross Lifeblood milk programme between January 2024 and April 2025 were invited to participate in a survey. The survey aimed to explore factors that make milk donors feel valued, evaluate their satisfaction with different aspects of the donation process, and identify barriers that may hinder continued donation. The survey included Likert-scale questions and optional open-text responses. The survey was completed by 257 donors (43.7% response rate). Most (72.4%) felt highly valued by Lifeblood, especially due to receiving milk bags, and having supportive, personal interactions with donor coordinators. However, some donors felt undervalued due to a lack of post-donation communication. Whilst satisfaction with the donation process was high, some respondents found the screening process repetitive and time-consuming. The most reported barrier was limited freezer space (67.7%), followed by time constraints, illness in the household, and the burden of cleaning and sterilising equipment for milk expression at home. Milk banks should adopt donor-centred practices, including streamlining processes to minimise time and effort required for donors, reduce costs incurred by donors where feasible, and enhance post-donation transparency and engagement
Bismuth Bicycles.
Full text linkBicyclic peptides are emerging as next generation therapeutics by combining the affinity and specificity of antibodies with the synthetic convenience of small molecules. Phage-encoded libraries of bicyclic peptides enable the discovery of high-affinity molecules against virtually any protein target. The generation of bicyclic peptides that advanced into clinical development involves the reaction of three cysteines in a peptide to a C3-symmetric alkylating agent. In phage display, this chemical modification transforms a pool of conformationally flexible peptides into a library of structurally unique protein mimetics that are able to bind traditionally challenging protein surfaces like those with limited structural definition. In recent years, a new class of bicyclic peptides has emerged using a single atom-bismuth-in place of C3-symmetric organic scaffolds, thus expanding into an unexplored chemical space at the intersection of inorganic chemistry and biology. This mini-review aims to reflect on the discovery, evolution and potential future applications of bismuth bicycle molecules
Polyanion Chemistry Engineers Ternary RNA Nanoparticle Structure/Function from the Inside-Out.
Full text linkFormulating cationic polyplexes (PP) with polyanions as ternary polyelectrolyte nanoparticles (TNP) offers a polymeric alternative to lipid nanoparticles (LNP) for targetable nucleic acid delivery. Although TNP in vivo transport is credited to their anionic surface charge, the relationships between polyanion chemistry and TNP structural stability, protein binding, and transfection are poorly understood compared to lipid-based systems. We hypothesized that carefully engineered hydrophobic polyanions could simultaneously endow TNPs with negative surface charge and enhanced extracellular stability critical to the future development of actively targeted formulations. We synthesized chemically diverse PEGylated polyanions to coat self-amplifying RNA (saRNA) PP, systematically studying how PEG architecture and polyanion chemistry modulate TNP structure and function. In both high-throughput stability assays and Small Angle Neutron Scattering structural studies, we found that PEG5k-bl-polyanion5k yields remarkably small particles with a pH-responsive core-shell structure. We identify a lead formulation (TNP5) with moderate hydrophobicity and charge density that balances extracellular stability and intracellular unpackaging for transfection. In agreement with spectroscopic characterization and in vitro cell studies, Molecular Dynamics simulations support the hypothesis that polyanions dictate TNP function from the inside-out by excluding water from the RNA core and by exposing functional groups that modulate protein binding. Our work correlates high throughput assays and detailed neutron scattering analysis to uncover mesoscale structural differences between two- and three-component polyelectrolyte delivery systems. These screening methods and the critical balances between polymer properties they uncover establish a framework for high throughput engineering of pH-responsive nanoparticle structure/function to navigate biological barriers to RNA delivery
Computation of FCC-ee sensitivity to heavy new physics with interactions of any flavor structure
Full text linkWe present a tool to compute the sensitivity of the Future Circular Electron-Positron Collider (FCC-ee) to the interactions of new, heavy particles via publicly available extensions to the and computer programs. We parametrize new particles’ effects without any flavor assumptions and take into account the projected experimental and correlated theoretical uncertainties of various electroweak and Higgs observables at the proposed collider. We illustrate a use of the tool by estimating the sensitivity of the FCC-ee to a Z ′ model with flavor-specific couplings, which explains anomalies inferred from present-day measurements and Standard Model predictions of observables that involve the b → s ℓ + ℓ − transition
Experience and Acceptability of a Reduced-Energy Whole-Diet Intervention in Women with Gestational Diabetes: a Qualitative Study of the Dietary Intervention in Gestational Diabetes Trial.
Full text linkBACKGROUND: Gestational diabetes mellitus (GDM) is rising in prevalence in many countries worldwide. Although dietary modifications are the first-line treatment for GDM, it is unclear which specific dietary approaches are most effective to improve maternal and offspring outcomes while reducing further maternal weight gain. We recently demonstrated benefits of an energy-restricted diet with modest weight loss in women with GDM. OBJECTIVES: We aimed to investigate the acceptability of an energy-restricted whole-diet intervention in women with GDM with a BMI ≥25 kg/m2, in a free-living environment, and to examine potential barriers and enablers of implementation of such a diet into standard clinical care. METHODS: This qualitative research study used semistructured interviews with 20 participants in the Dietary Intervention in Gestational Diabetes trial, in which women with GDM were randomized to a whole-diet intervention containing 1200 or 2000 kcal/d. We used reflexive thematic analysis to explore participants' experiences of the study diet and GDM. RESULTS: We identified 6 key themes in participants' experience: emotional and cognitive burden of managing GDM, convenience of meal delivery, support and reassurance, hunger and appetite differences, health impacts for intervention engagement, and research participation for awareness and impact. Facilitators of study participation included support, motivation, convenience, and not wanting to be medicated. Barriers to participation were the social aspects of eating food, inconvenience, and uncertainty about the validity of dietary interventions. It was identified that participants frequently overlooked their physical health and weight management during pregnancy, despite how crucial these factors are for both maternal and infant well-being. CONCLUSIONS: Pregnant women with GDM found an energy-restricted diet to be acceptable and beneficial to emotional and physical health, especially when support is provided by healthcare professionals. The convenience of meal delivery and the motivations to avoid medication use in pregnancy facilitated engagement with the intervention.This trial was registered at ISRCTN registry as ISRCTN 65152174 (https://www.isrctn.com/ISRCTN65152174)
Continuity of eastern Beringian megafauna phylogenetic diversity following deposition of the Late Pleistocene Dawson tephra.
Full text linkVolcanic eruptions can deposit ash, or tephra, across the landscape hundreds to thousands of kilometers from the source volcano. The ecological and genetic effects of ancient ashfall events are only known sparsely from the geological record and from modern genomic studies. About 29,000 years ago, a volcanic eruption in the Aleutian archipelago deposited ash across the eastern Beringian mammoth steppe. The resulting Dawson tephra is visible in loess deposits in interior Alaska and Yukon, with thicknesses ranging from 5 to 80 cm at a distance of 1,700 km from its source. To explore the impact of this ashfall event on ecosystem dynamics, we used sedimentary ancient DNA (sedaDNA) approaches to isolate population and community level genomic data from several exposures of Dawson tephra in the Klondike region of Yukon, Canada. We found no significant changes to species assemblages associated with the ashfall event, and no significant change in megafauna phylogenetic diversity after the ashfall. Our results suggest that the Beringian mammoth steppe ecosystem was resilient to ecological disturbance and reinforce the value of sedaDNA to investigate past environmental dynamics
THE FORTUNES OF PERTINAX: BURTON AND JOHNSON
Full text linkThis note revises a note in the Clarendon edition of Robert Burton's Anatomy of Melancholy by investigating the ultimately indeterminate provenance of Burton's Latin phrases concerning irreligious sceptics. It will then propose that this very passage in the Anatomy, together with the work's conclusion, forms a composite source for Samuel Johnson's figure of Pertinax in issue 95 of The Rambler
Valuing Wealth, Building Prosperity
Full text linkThe 12 months since the launch of the Bennett Institute’s Wealth Economy research programme have brought more progress in terms of our research and its impact on decision makers than we could have foreseen. The fundamental message – that sustained prosperity will depend on stewardship of the whole portfolio of society’s assets, which therefore need to be properly measured and understood – has struck a chord.
During this first year we focused on natural capital, particularly climate, and social capital. In recent years there has been little evidence on the empirical relationships between trust, social capital, and the economy as a whole. We have demonstrated that meaningful measurement of social capital is feasible, and that this helps explain ‘hard’ economic outcomes like productivity growth. We have provided an additional important lens on accounting for CO2 in terms of the damage caused by climate change – so that while for example Australia accounts for just 1.3% of global CO2 production, it is on track to experience between 12 and 24 times more damage from climate change than the world per capita average. These findings and more, from the dynamics of tackling emissions to the financial market consequences, are described in this report
The B-class auxin response factor MpARF2 is essential for meristem organization in free-living plant gametophytes.
Full text linkLand plants (embryophytes) are multicellular eukaryotes with a remarkable capacity to grow continuously during their life span. They achieve this by maintaining a reservoir of pluripotent stem cells in their meristems. In embryophytes, including both bryophytes and tracheophytes, the haploid gametophytic generation is inferred to be ancestrally free living. Gametophyte meristems are sites of auxin biosynthesis, but auxin promotes differentiation, and conversely, a lack of auxin results in the loss of differentiation. We report that in the liverwort Marchantia polymorpha, pluripotent stem cells are protected from auxin-mediated differentiation by the single B-class auxin response factor (MpARF2), an embryophyte-specific gene that antagonizes auxin responses. We describe the critical role of MpARF2 in meristem establishment and maintenance using reporter lines, loss- and gain-of-function alleles, and gene-interaction experiments. Mparf2 knockdown and knockout alleles, respectively, fail to maintain and form a functional meristem across developmental transitions, while overexpression of MpARF2 is sufficient to create additional meristems in dormant gemmae. Despite being an auxin-signaling antagonist, MpARF2 positively regulates auxin production by activating a YUCCA (MpYUC2) auxin biosynthetic enzyme in stem cells. Conversely, auxin responses mediated by the single A-ARF (MpARF1) antagonize both auxin production and MpARF2 expression in differentiating neighbor cells, creating a multicellular incoherent feedforward loop that limits meristem size. We propose that MpARF2 and auxin form a meristem organizer-modulating auxin insensitivity at the site of auxin production while providing signaling information to surrounding differentiating cells-and that this organizer was critical for the emergence of indeterminate growth in the ancestral embryophyte