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Relationship between recovery from COVID-19-induced smell loss and general and oral health factors
Get PDFFunding: This research was funded by the Tattersall Foundation. The APC was funded by the University of Dundee Library and Learning Centre.Background and Objectives Loss of smell is one of the strongest predictors of coronavirus disease 2019 (COVID-19) and can persist long after other symptoms have resolved. "Long" cases (>28 days) of smell dysfunction present future challenges to medical and dental professionals, as there is a lack of evidence on the causes and any exacerbating or relieving factors. This study aimed to explore the persistence of COVID-19-induced smell loss and association with physical, lifestyle and oral health factors. Materials and Methods This study was a cross-sectional survey of 235 participants. Recovery of smell was explored, comparing rapid recovery (≤28 days) with prolonged recovery (>28 days). Associative factors included age, sex, illness severity, diet, BMI, vitamin D supplementation, antidepressants, alcohol use, smoking, brushing frequency, flossing, missing teeth, appliances and number of dental restorations. Results: Smell loss showed 87% resolution within 30 days. Prolonged smell loss was significantly associated with older age (mean ± 95%, CI = 31.53 ± 1.36 years for rapid recovery vs. mean ± 95%, CI = 36.0 ± 3 years for prolonged recovery, p = 0.003) and increased self-reported illness severity (mean ± 95%, CI = 4.39 ± 0.27 for rapid recovery vs. 5.01 ± 0.54 for prolonged recovery, p = 0.016). Fisher's exact test revealed flossing was associated with rapid recovery, with flossers comprising 75% of the rapid-recovery group, compared to 56% in the prolonged-recovery group (odds ratio ± 95%, CI = 2.26 (1.23-4.15), p = 0.01). All other factors were not significantly associated (p > 0.05). Conclusions Increased age and illness severity were associated with prolonged smell recovery. Use of floss was the only modifiable factor associated with rapid recovery of smell loss. As 87% of cases resolve within 30 days, future studies may benefit from targeted recruitment of individuals experiencing prolonged sense loss. This would increase statistical confidence when declaring no association with the other factors assessed, avoiding type II errors.Peer reviewe
MicroED characterization of a robust cationic σ-alkane complex stabilized by the [B(3,5-(SF5)2C6H3)4]- anion, via on-grid solid/gas single-crystal to single-crystal reactivity
Get PDFFunding: EPSRC (EP/M024210/2, DTP studentship to EAT and ALB), The Wellcome Trust (206161/Z/17/Z), SCG Chemicals.Microcrystalline (∼1 μm) [Rh(Cy2PCH2CH2PCy2)(norbornadiene)][S-BArF4], [S-BArF4] = [B(3,5-(SF5)2C6H3)4]−, reacts with H2 in a single-crystal to single-crystal transformation to form the σ-alkane complex [Rh(Cy2PCH2CH2PCy2)(norbornane)][S-BArF4], for which the structure was determined by microcrystal Electron Diffraction (microED), to 0.95 Å resolution, via an on-grid hydrogenation, and a complementary single-crystal X-ray diffraction study on larger, but challenging to isolate, crystals. Comparison with the [BArF4]− analogue [ArF = 3,5-(CF3)2(C6H3)] shows that the [S-BArF4]− anion makes the σ-alkane complex robust towards decomposition both thermally and when suspended in pentane. Subsequent reactivity with dissolved ethene in a pentane slurry, forms [Rh(Cy2PCH2CH2PCy2)(ethene)2][S-BArF4], and the catalytic dimerisation/isomerisation of ethene to 2-butenes. The increased stability of [S-BArF4]− salts is identified as being due to increased non-covalent interactions in the lattice, resulting in a solid-state molecular organometallic material with desirable stability characteristics.Peer reviewe
The impact of selective fluorination on the properties of aliphatic and bioactive molecules
Get PDFThis thesis explores the role that selective fluorination can have on the behaviour and bioactivity of selected aliphatic organic compounds.
In Chapter 1, an introduction is given to the element fluorine and the effects it can produce in organic chemistry related to its electronegativity.
In Chapter 2, the conformational equilibria of selectively halogenated cyclohexanes were explored both experimentally and computationally and the role of nonclassical hydrogen bonding (NCHB) is highlighted in favouring the axial conformation in 1,1,4-tri-fluorocyclohexane. In Chapter 3, a series of compounds were prepared using methods of asymmetric synthesis to test the hypothesis of a hydrogen bonding interaction between (R)-citronellol and the human olfactory receptor (OR1A1). A series of fluorinated and methylated isomer analogues of (R)-citronellol were also prepared and assayed against native and mutant OR1A1 receptors. In Chapter 4, a series of all cis- fluorinated (Janus face) cyclohexanes with progressively increasing levels of fluorine were incorporated into an amino acid and introduced into the W-peptide for assay against the formylpeptide receptor FPR2, a G-protein coupled receptor. These amino acids were also incorporated into ketopiperazine architectures for assay against trypanosomatid parasites in order to explore the level of fluorination on their bioactivity, particularly as the rings become more polar.
In Chapter 5, an ‘‘Experimental’’ section is given which outlines in detail the experimental methods used throughout the research and describes synthesis protocols and the analyses of prepared compounds
Fast synthesis of n-type half-Heusler TiNiSn thermoelectric material
Get PDFFunding: This work was supported by the Energy Entrepreneurs Fund (ATHLETE).The n-type half-Heusler TiNiSn is very promising for thermoelectric applications in the medium temperature range. However, the synthesis of TiNiSn often involves long annealing times (up to several weeks) to obtain a single phase, which is a major barrier to scaling-up. In this work, TiNiSn was synthesized by a combination of arc-melting, ball-milling and spark plasma sintering. The obtained samples with diameters up to 30 mm had high-purity, high-density and fine-grains. Without the need for an annealing step, the total synthesis time was significantly shortened. Addition of Cu was used to optimize the thermoelectric properties of TiNiSn, and a maximum figure of merit of 0.6 was achieved at 773 K. The fast and scalable synthesis of TiNiSn with good thermoelectric performance presented in this work opens up the possibility of industrial scaling-up.Peer reviewe
Greedy base sizes for sporadic simple groups
Get PDFFunding: Coen del Valle’s research is supported by the Natural Sciences and Engineering Research Council of Canada (NSERC), funding reference number PGSD-577816-2023, as well as a University of St Andrews School of Mathematics and Statistics Scholarship.A base for a permutation group G acting on a set Ω is a sequence ℬ of points of Ω such that the pointwise stabiliser Gℬ is trivial. Denote the minimum size of a base for G by b(G) There is a natural greedy algorithm for constructing a base of relatively small size; denote by (G) the maximum size of a base it produces. Motivated by a longstanding conjecture of Cameron, we determine (G) for every almost simple primitive group G with socle a sporadic simple group, showing that (G) = b(G) .Peer reviewe
Gravitationally localized states of two neutral fermions interacting with a Higgs field
Get PDFFunding: P. E. D. L. acknowledges funding from a St. Leonards scholarship from the University of St. Andrews and from UKRI under EPSRC Grant No. EP/R513337/1. A. D. L. is grateful for financial support from the EPSRC (UK) under Grant No. EP/L505079/1.We present localized “particlelike” states composed of a pair of neutral fermions interacting with a scalar Higgs field and the metric of spacetime, extending the Einstein-Dirac formalism introduced by Finster et al. [Particlelike solutions of the Einstein-Dirac equations, Phys. Rev. D 59, 104020 (1999)]. We demonstrate that, when the coupling between the fermions and the Higgs field is strong, there is a class of states in which the total (ADM) mass no longer increases proportionally to the mass of the constituent fermions; indeed it decreases. This phenomenon enables fermionic particles with much larger masses than in the Higgs-free case to form localized states.Peer reviewe
The reconfiguration of mestizaje and whiteness in the diaspora
Get PDFAs a light-skinned mestiza Mexican woman, I have enjoyed the privileges of ‘whiteness’ in Latin America. In this article, I talk about how my whiteness has helped me in the development of my own fieldwork with Latin American migrants in London, that is among other mestizas who have similar understandings of the complexities and contradictions of mestizaje and whiteness in the region. I engage with the literature on white passing to explore the shifting terrain of ‘passing’ through time in a new context in the diaspora. Reflecting on the embodiment of my own mestizaje, I explore the problems that this cultural notion has produced in my country, and the ways in which I have come to understand and reformulate it while living as a non-white person in the UK. I do it via my personal experience of race and ethnicity, of racism abroad, and through my own work with Latin American migrants.Peer reviewe
Hollywood is burning : imagery and polycrisis
Get PDFIn early January 2025, wildfires swept through several regions of Los Angeles, California. The fires' proximity to Hollywood, the epicentre of Western visual and cinematic production, lead to the creation and wide circulation of real and artificially generated images on social media. In this article, I argue two things: first, that these images capture human concerns in the age of polycrisis; and second, by interpreting these images as symptoms of an attempt to articulate a sense of reality in which human imagination has itself become under threat, public humanists of the present and future need to be attuned to their role as mediators of diverse publics and their way of making sense under these crisis conditions. This article thus uses selected imagery of Los Angeles's wildfires circulating on social media to excavate how ways of meaning-making in a digital age (memeification, use of generative artificial intelligence) reflect real public concerns about polycrisis, rendering these images productive beyond their satirical or misinforming values.Peer reviewe
Foundational uncertainties in terminal Ediacaran chronostratigraphy revealed by high-precision zircon U-Pb geochronology of the Nama Group, Namibia
No full textFunding: MO and FM acknowledge funding from Swiss National Science Foundation grant 200021_182556. FB and RW acknowledge support from the Natural Environment Research Council (NERC grant NE/T008458/1). FB acknowledges support from UKRI Project EP/Y008790/1. BM acknowledges support from Genus: DSI-NRF Centre of Excellence in Palaeoscience under Grant No. 86073.The Nama Group of southern Namibia and northwestern South Africa hosts the best-dated mixed carbonate-siliciclastic foreland basin succession of the terminal Ediacaran [ca. 551 million years (Ma) ago to 1 Myr older than the depositional age of their respective ash beds when assuming existing stratigraphic correlations. If this scenario is preferred, then a cautious approach would be to consider all weighted mean zircon U-Pb ages from ash beds to reflect maximum depositional ages. Both scenarios support deposition of the Huns Member >540 Ma in the Swartpunt area if the oldest weighted mean age reported here represents a near-depositional age, which has significant implications for the temporal calibration of important terminal Ediacaran ichnofossil assemblages and future cyclostratigraphic studies. Stratigraphic correlations common to both scenarios allow us to temporally calibrate a basin evolution model for the Nama Group. Temporal trends in initial hafnium isotope (εHf) compositions of zircon grains from ash beds throughout the succession may support progressive crustal thickening associated with underplating of the Damara orogenic belt along the northern periphery of the Kalahari craton from ca. 547 Ma to ca. 538 Ma. The compilation of new and published zircon U-Pb ages may also imply that the locus of carbonate platform development migrated from north to south (present co-ordinates), tracking the migration of foredeep subsidence.Peer reviewe
Examining societal barriers to energy transition in South Africa : opportunities for energy justice and solar energy?
Get PDFThis PhD is set against the background of the increasing challenge of climate change. There is a need for the world to turn away from fossil fuels – which are the largest source of greenhouse gases - and embrace the opportunities of renewable energy. The purpose of this work is to examine a complex case study through twin questions: what barriers are preventing the large-scale deployment of South Africa’s significant resources of solar energy, and what is their significance to the delivery of energy justice in that society. The argumentation is developed through two literature reviews and a suite of 28 semi-structured interviews held with key personnel in South Africa during May and June 2018.
The results obtained involve the identification and ranking of six key societal barriers to an energy transition in South Africa, setting them in a framework of an 8-way generic taxonomy of barrier types. The South African barriers are analysed to assess not only how and why they are acting to impede an energy transition, but also how they are preventing the delivery of energy justice. The latter has led to a recommendation that the study of energy justice must concentrate on the dynamics of the subject, including a focus on outcomes rather than process, an understanding of the development of energy justice within an energy transition, and the use of measurable proxies (such as solar energy) in the place of energy justice.
The study has also developed techniques for representing both the generic barriers and the South African barriers graphically, for ease of communicating the findings. Further research applications of the approach developed in this PhD are then identified. The study concludes with policy and research recommendations to enhance the prospects of a successful – and just – energy transition in South Africa
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