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Mechanophotocatalysis : towards a generalisable methodology for solvent-minimised light-driven organic synthesis reactions
No full textThis thesis aims to combine photocatalysis with mechanochemistry in order to conduct solvent-minimised light-driven organic synthesis reactions, and to explore the benefits of this synergistic union. Chapter 1 introduces the underlying principles and synthetic value of photocatalysis, and the issues associated with using organic solvents as reaction environments, before describing the design principle of mechanophotocatalysis. Chapter 2 details the development of a mechanophotocatalysis reactor and prototype reaction vessels, and the application of mechanophotocatalysis to four archetypal photocatalytic reactions. Notably, we report the first example of a solvent-minimised photocatalysis reaction possessing an enhanced tolerance to air when compared with the solution-state analogue reaction. Chapter 3 reports an improved reaction vessel design, and applies the methodology to four industrially relevant metallaphotoredox catalysis reactions. Mechanophotocatalysis enabled significant reductions in the use of problematic organic solvents, such as N,N-dimethylacetamide, and facilitated a cross-electrophile coupling possessing an increased tolerance to aerobic conditions relative to the solution-state reaction. Chapter 4 probes the behaviour of the excited states of five archetypal photocatalysts in solution and in the solid-state using absorption and photoluminescence spectroscopies. Crucially, the excited states of the photocatalysts were quenched more significantly by oxygen in solution than as solids, which likely contributes to the increased tolerance to aerobic conditions that mechanophotocatalysis reactions can experience. Chapter 5 details the use of a poorly soluble sacrificial electron donor, sodium ascorbate, in a net reductive mechanophotocatalysis system. The solvent-minimised protocol returned more consistent results than the solution-state reference reaction, highlighting mechanophotocatalysis as a valuable tool for mediating highly heterogeneous photocatalytic reactions. Chapter 6 demonstrates proof-of-principle studies for scaling mechanophotocatalysis using extrusion technologies towards developing continuous solvent-minimised light-driven reactions."This work was supported by the University of St Andrews (School of Chemistry); and the East of Scotland Industrial Catalysis (EaSI-CAT) Centre for Doctoral Training (CDT)."--Fundin
Bipolar volcanic ice-core synchronization of the entire last glacial period
Get PDFFunding: AS and DDJ were funded by the European Union (ERC, Green2Ice, 101072180). EW was supported by a Royal Society Professorship. CB gratefully acknowledges funding from the US National Science Foundation (award 2315928). HAK was funded by the H2020 project TiPES (820970), H2020 project P2F (101184070) and the Danish DFF project (1131-00007B). We acknowledge US NSF awards 2102917 and 1702830 for GISP2 sulfur measurements contributed by JRM, NC, and SW. AB gratefully acknowledges funding from a Philip Leverhulme prize in Earth Sciences (PLP-2021-167). FP acknowledges the funding by CNR/INSU/LEFE for the IceChrono and CO2Role projects. M. Sigl received funding from the European Research Council under the European Union's Horizon 2020 research and innovation programme (grant number: 820047).Precise synchronization of paleoclimate records is essential for inferring the dynamics and past evolution of the climate system. For the last glacial period, the time scales of ice cores from the Greenland and Antarctic ice sheets have been synchronized by the use of cosmogenic radionuclides, atmospheric gas concentrations, and traces of large volcanic eruptions. Here we identify the sulfate deposition signatures of the same 300 volcanic eruptions in different Greenland and Antarctic ice cores to obtain an inter-hemispheric volcanic ice-core synchronization of the entire last glacial period and the early Holocene (10–110 ka). Compared to earlier bipolar volcanic synchronizations, we close a gap in the period 16.5–24.5 ka and extend the synchronization to cover the 10–12 ka and 60–110 ka intervals. Furthermore, we increase the density of bipolar match points and make updates and corrections of the existing bipolar and unipolar synchronizations. The volcanic synchronization is in agreement with existing bipolar synchronizations from independent 10Be and methane matching. The bipolar volcanic synchronization allows us to determine the precise phasing of interhemispheric abrupt climate events throughout the last glacial period, particularly those associated with Dansgaard-Oeschger (D-O) events. Our improved synchronization and extended time period allow us to show that at the time of the D-O warming transitions, the average Antarctic temperature reaches a maximum within decades after the Greenland temperature maximum. This rapid Antarctic warming is superimposed on the well-known millennial-scale thermal bipolar-seesaw warming in Antarctica commonly attributed to oceanic heat transport and confirms earlier work that the abrupt change observed in Greenland is associated with a direct atmospheric circulation change at a global scale. The exception to this pattern occurs for the EDML ice-coring site located in the Atlantic sector of Antarctica, potentially related to sea-ice conditions in the Weddell Sea. Comparison to state-of-the-art climate model simulations shows excellent agreement in the overall bipolar climate phasing at the warming transitions and allows for analysis of the climate-system behavior at those transitions. The model simulations suggest that the abrupt Antarctic warming response observed is connected with an interhemispheric atmospheric response involving a global scale reorganization of the zonal mean atmospheric circulation. The abrupt D-O surface warming signal in the Northern Hemisphere is teleconnected into an abrupt Antarctic surface warming through changes in the Southern Hemisphere eddy-driven jet and anomalous circulation changes in the associated Ferrel and Polar cells.Peer reviewe
Modular nanoparticle platform for solution-phase optical sensing of protein–protein interactions
Get PDFFunding: The authors gratefully acknowledge funding support from the Helmholtz Pioneer Campus and Helmholtz Munich, the Volkswagen Foundation, SFB1035, TUM Innovation Network NextGenDrugs funded by the Federal Ministry of Education and Research (BMBF) and the Free State of Bavaria under the Excellence Strategy of the Federal Government and the Länder, ScotCHEM and the Scottish Government under the SFC Saltire Emerging Researcher ScotCHEM European Exchanges Scheme, U.S. Army Research Office (W911NF-20-1-0233), and the EPSRC via EP/L017008/1, EP/R023751/1, and EP/T019298/1.Protein–protein interactions regulate essentially all cellular processes. Understanding these interactions, including the quantification of binding parameters, is crucial for unraveling the molecular mechanisms underlying cellular pathways and, ultimately, their roles in cellular physiology and pathology. Current methods for measuring protein–protein interactions in vitro generally require amino acid conjugation of fluorescent tags, complex instrumentation, large amounts of purified protein, or measurement at extended surfaces. Here, we present an elegant nanoparticle-based platform for the optical detection of protein–protein interactions in the solution phase. We synthesized gold-coated silver decahedral nanoparticles possessing high chemical stability and exceptional optical sensing properties. The nanoparticle surface is then tailored for specific binding to commonly used polyhistidine tags of recombinant proteins. Sequential addition of proteins to the nanoparticle suspension results in spectral shifts of the localized surface plasmon resonance that can be monitored by conventional UV–vis spectrophotometry. With this approach, we demonstrate both the qualitative detection of specific protein–protein interactions and the quantification of equilibrium and kinetic binding parameters between small globular proteins. Requiring minimal protein quantities and basic laboratory equipment, this technique offers a simple, economical, and modular approach to characterizing protein–protein interactions, holds promise for broad use in future studies, and may serve as a template for future biosensing technologies.Peer reviewe
Cervical whole-slide images dataset for multiclass classification
No full textFunding: This work is supported by the Industrial Centre for AI Research in digital Diagnostics (iCAIRD), which is funded by Innovate UK on behalf of UK Research and Innovation (UKRI) [project number: 104690] and in part by Chief Scientist Office, Scotland.Background: The clinical pathway for the prevention and treatment of cervical cancer depends on cytology and then the assessment of biopsy specimens, fragments of tissue removed for histological examination. This can be a significant workload and is an obvious exemplar to explore triage based on machine learning analysis of slides. Limited access to large annotated datasets of human diseased tissue is a major obstacle to developing standards and algorithms that can assist diagnosis. Results: We present a dataset comprising 2,539 whole-slide images of cervical biopsy specimens, each annotated by several pathologists and consensus on diagnosis and individual features agreed. Each whole-slide image represents 1 slide per patient in iSyntax format, with manual annotations by pathologists in Jason format. Each whole-slide image is assigned a category label, which is the final diagnosis of the image, and a subcategory label, which declares in which subcategory the image is found. Conclusion: This dataset has been used to build a model that accurately predicts diagnosis, allowing the possibility of automatically triaging biopsy specimens, so that the most significant pathologies can be identified rapidly and those patients selected for immediate treatment. The level of annotation, at the subslide level, and the number of cases are unique in public databases and should allow investigators to explore multiple aspects of computer vision relevant to human tissue diagnosis, with no limitation placed on access to the whole-slide images.Peer reviewe
Life as a cosmic phenomenon facing human culture
Get PDFWe present perspectives from six panellists on “Life as a cosmic phenomenon facing human culture”, contrasting our experience and knowledge of life as found on Earth with the vastness of the Universe and the fact that Earth-centric and/or anthropocentric views have repeatedly proven untenable. How does an outwards view of projecting Earth-based experience into the cosmos combine with the inwards view of the potential detection of life beyond Earth telling us who we are
Fairness for sale : the hidden costs of international language tests
No full textThis Counterpoint challenges the claim that international standardised assessments benefit both learners and teachers. While acknowledging that such tests are unlikely to disappear, we argue that they harm language education. We first deconstruct the historical myths used to legitimise standardisation, revealing it as a rhetorical move that substitutes genealogy for evidence. We then trace the resulting harms in three ways: mechanistically, through overstandardisation that flattens language and threatens validity; systemically, through the economic machinery of the testing-industrial complex, where ‘edu-washing’ casts profit as benevolence; and ideologically, through a fiction of fairness that conflates sameness with justice, concealing raciolinguistic, and algorithmic biases. Against this, we propose a human-centred re-orientation of assessment, where validity is both statistical and ethical, and fairness an ongoing relationship rather than a calculation. Reform, we suggest, will not come from better metrics but from empathy, from a willingness to remember what it feels like to be measured.Peer reviewe
Antinatalism and ecotheology : reflections through Laudato Si'
No full textThis thesis examines antinatalism – the belief that procreation is morally objectionable – through the lens of Christian ecotheology. It argues that the rising cultural resonance of antinatalist thought reflects not merely existential despair, but also a theologically significant symptom of ecological dislocation which contributes to the demographic transition and low fertility rates.
Part I explores the foundations of ecotheology through the concept of Authentic Human Development. It critiques the political architecture of the modern polis and contends that nature must now be regarded as “the new poor” in a suffering and disordered world. Drawing on the theological-ethical framework of Laudato Si' (2015), this section engages authors including Ernst Conradie, Sallie McFague, Christopher Southgate, Alister McGrath, and Hans Urs von Balthasar.
Part II investigates the intellectual genealogy of philosophical pessimism and the emergence of contemporary antinatalism as a form of anthropodicy. It analyzes the work of Arthur Schopenhauer, Friedrich Nietzsche, Peter Wessel Zapffe, Julio Cabrera, and David Benatar, identifying a shared logic of despair rooted in human alienation from both God and nature.
Part III proposes a dialogical synthesis. It argues that antinatalism, as both a worldview and a demographic phenomenon, signals the collapse of anthropocentric illusions and a growing ecological anxiety. In response, the thesis advocates for a theologically grounded resistance to antinatalism and demographic decline through the liberation and embrace of nature – framed by the inseparability of human and ecological value. It promotes hope through political transformation and ecological conversion, enacted proleptically through imitatio Christi.
While antinatalism rejects the human condition of suffering, Christian ecotheology – particularly in Pope Francis’ Laudato Si' – offers a vision of utopian renewal rooted in the ethical reorientation of humanity towards nature as the new poor. This thesis seeks to initiate a sustained theological engagement with antinatalism, a dialogue largely absent from contemporary scholarship
k-universality of regular languages
No full textFunding: Duncan Adamson’s work was funded by the Leverhulme Trust via the Leverhulme Research Centre for Functional Material Design. Tore Koß’ work was supported by the DFG project number 389613931. Florin Manea’s work was supported by the DFG Heisenberg-project number 466789228.A subsequence of a word w is a word u such that u=w[i1]w[i2]…w[ik][jls-end-space/], for some set of indices 1≤i1<i2<…<ik≤|w|[jls-end-space/]. A word w is k-subsequence universal over an alphabet Σ if every word in Σkappears in w as a subsequence. In this paper, we study the intersection between the set of k-subsequence universal words over some alphabet Σ and regular languages over Σ. We call a regular language L k-∃-subsequence universal if there exists a k-subsequence universal word in L, and k-∀-subsequence universal if every word of L is k-subsequence universal. We give algorithms solving the problems of deciding if a given regular language, represented by a finite automaton recognising it, is k-∃-subsequence universal and, respectively, if it is k-∀-subsequence universal, for a given k. The algorithms are FPT w.r.t. the size of the input alphabet, and their run-time does not depend on k; they run in polynomial time in the number n of states of the input automaton when the size of the input alphabet is O(logn)[jls-end-space/]. Moreover, we show that the problem of deciding if a given regular language is k-∃-subsequence universal is NP-complete, when the language is over a large alphabet. Further, we provide algorithms for counting the number of k-subsequence universal words (paths) accepted by a given deterministic (respectively, non-deterministic) finite automaton, and ranking an input word (path) within the set of k-subsequence universal words accepted by a given finite automaton.Peer reviewe
Methodological assumptions and limitations of life expectancy estimates for minoritised ethnic groups in the UK : implications for validity, practice, and policy
No full textFunding: This work was funded by the Nuffield Foundation.Experimental life expectancy estimates calculated by the Office for National Statistics (ONS) for the period 2011 to 2014 show significantly longer life expectancy for minoritised ethnic groups in England and Wales when compared with the white majority. These findings are in contrast to a large body of evidence of poorer health outcomes among certain minoritised ethnic groups (predominately Bangladeshi, Black Caribbean, Gypsy/Traveller and Pakistani groups), and have serious practice and policy implications if taken as definitive. We examine the data and methodology used by the ONS in producing these estimates, and consider the sources of error in that approach. We find that the estimates for minoritised ethnic groups exhibit high sensitivity to error that is not seen in the estimates for the White British population; although we note that even in our largest error scenario, many minoritised ethnic groups still have higher life expectancy than the White British group. Although the results are supported by evidence around the “healthy migrant” effect, and other global research on life expectancy by ethnic group, there is a risk that the ONS’ life expectancy estimates of minoritised ethnic groups may be being inflated due to the large amount of missing data among these groups, and the potential for those missing cohorts to be at higher risk of morbidity and mortality. The ONS’ estimates, while clearly labelled as experimental, have been used in academia, policy and the press without necessary caveats. We remind researchers of the experimental nature of the ONS’ life expectancy by ethnic group estimates, and advise caution in how they are used.Peer reviewe
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