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Redesign of Plastic Packaging for Fresh Fish Transport: Lightweight design based on numerical and experimental investigations of structural and thermal behavior
(University of Iceland, School of Engineering and Natural Sciences, Faculty of Industrial Engineering, Mechanical Engineering and Computer Science, 2026-09-11) LU, ZIWEI; Björn Margeirsson; Fjóla Jónsdóttir; Sigurjón Arason; Ólafur Ögmundarson; Faculty of Industrial Engineering, Mechanical Engineering and Computer Science (UI); Iðnaðarverkfræði-, vélaverkfræði- og tölvunarfræðideild (HÍ); School of Engineering and Natural Sciences (UI); Verkfræði- og náttúruvísindasvið (HÍ)
The increasing demand for sustainable cold-chain logistics has created a need for lighter and more environmentally efficient packaging for fresh food transport. This thesis investigates the structural, thermal, and environmental performance of expanded polystyrene (EPS) boxes and rotomolded polyethylene (PE) food tubs used in the transport of fresh fish products. The objective is to develop lighter packaging solutions while maintaining the mechanical strength and thermal insulation required for chilled food distribution. The study combines experimental testing, microstructural analysis, finite element analysis (FEA), and life cycle assessment (LCA) to relate material properties to the overall performance of EPS boxes. Experimental results for EPS boxes show that small density variations significantly increase material modulus, and influence the stiffness and stacking strength of the EPS box. Using a calibrated FEA framework, an improved EPS design achieved an 11% reduction in box weight. This reduced the environmental impact across all major LCA categories while causing a 9% reduction in thermal insulation and negligible decrease in stacking strength. For PE food tubs, microstructural defects in the high-density polyethylene (HDPE) skin layer were found to substantially reduce material ductility. Simulations of industrial hoisting conditions further identified buckling of the handle as the dominant failure mode, providing a clear pathway for geometric optimization of load-bearing capacity in the elastic region. Overall, this work provides scientifically validated design guidelines for more sustainable cold-chain packaging and highlights the importance of advanced material models and stochastic numerical methods capable of accounting for the inherent microstructural variability in PE foams.
Heterologous and homologous prime-boost immunization strategies to enhance immune responses in early life
(University of Iceland, School of Health Sciences, Faculty of Medicine, 2026-09-14) Foroutan Pajoohian, Poorya; Stefanía Bjarnarsson; Ingileif Jónsdóttir; Faculty of Medicine (UI); Læknadeild (HÍ); School of Health Sciences (UI); Heilbrigðisvísindasvið (HÍ)
In early life the immune system is characterized by generation of weaker and less durable vaccine-induced antibody responses than in adulthood. This poses a major challenge for the development of vaccines targeting pathogens that require that both strong systemic and mucosal immune responses are elicited to achieve protective immunity. The overall aim of this thesis project was to determine how heterologous prime-boost immunization routes in comparison with the conventional parenteral homologous immunization shape early life humoral immunity to a pneumococcal conjugate vaccine, Pn1-CRM197, and to develop and characterize immunization strategies capable of improving both systemic and mucosal responses in early life. A neonatal mouse model was used in the study. Mice were immunized with Pn1-CRM197 formulated with the adjuvants CAF01 or mmCT for subcutaneous or intranasal administration, respectively. Across this PhD study, vaccine-specific IgG and IgA antibody responses, antibody-secreting cells, germinal center activity, T follicular helper and T follicular regulatory cells, memory B cell generation, plasmablast/plasma cell differentiation and their expression of the survival and activation receptors BAFF-R, TACI and BCMA were examined in spleen, cervical and inguinal lymph nodes and bone marrow. Immunization schedules that included a mucosal administration enhanced vaccinespecific IgA responses in serum and mucosal compartments compared with homologous subcutaneous immunization. However, heterologous subcutaneous priming followed by intranasal booster, while improving mucosal output and generating combined systemic–mucosal responses, did not induce systemic IgG responses comparable to homologous subcutaneous/subcutaneous immunization. Our results showed that the routes of immunizations determined the anatomical site of germinal center induction and shaped the germinal center output. Homologous subcutaneous/subcutaneous immunization preferentially induced germinal center responses in spleen and inguinal lymph nodes, promoted plasmablast/plasma cell differentiation in spleen, increased expression of the survival receptor BCMA on plasma cells in inguinal lymph nodes and yielded high systemic IgG responses. In contrast, heterologous subcutaneous/intranasal immunization redirected the induction of plasmablast/plasma cells responses, BCMA expression toward cervical lymph nodes and favoured the generation of IgM⁺ germinal center-derived memory B cells in all lymphoid organs assessed, and with enhanced BAFF-R and TACI expression, receptor crucial for survival and re-activation, together with stronger IgA responses. The major finding of my study was that reversal of the heterologous immunization schedule, consisting of intranasal priming and subcutaneous booster, successfully overcame the main limitation of the heterologous immunization schedule. It preserved the mucosal advantage of intranasal immunization while inducing systemic IgG responses comparable to homologous subcutaneous/subcutaneous immunization, alongside enhanced serum and salivary IgA responses, increased bone marrow homing of BCMA⁺ plasmablasts/plasma cells, expanded memory B cell output but maintained the favoured generation of IgM⁺ germinal center-derived memory B cells in all lymphoid organs. Together, these studies demonstrate that in early life, the route and order of primeboost immunization affect not only the magnitude, but also the localization and quality of humoral immunity. Among the immunization strategies tested, intranasal priming followed by subcutaneous booster emerged as the most suitable approach, combining robust systemic immunity and mucosal responses, enhanced bone marrow homing of BCMA⁺ plasmablasts/plasma cells and expanded memory B cell output. These findings provide a framework for the rational design of early life vaccination strategies against respiratory pathogens.
Development of a Vibrotactile Wearable for Real-Time Information Communication
(University of Iceland, School of Engineering and Natural Sciences, Faculty of Industrial Engineering, Mechanical Engineering and Computer Science, 2026) Yeganeh, Nashmin; Prof. Dr. Rúnar Unnþórsson; Faculty of Industrial Engineering, Mechanical Engineering and Computer Science (UI); Iðnaðarverkfræði-, vélaverkfræði- og tölvunarfræðideild (HÍ); School of Engineering and Natural Sciences (UI); Verkfræði- og náttúruvísindasvið (HÍ)
In a digital environment saturated with information, there is an increasing need for new ways to deliver information quickly and reliably without relying on sight or hearing. This is especially critical when these senses are already overloaded or otherwise unavailable. Vibrotactile stimulation, where information is conveyed through vibrations on the skin, shows great promise as a way to utilize the body’s sense of touch. The effectiveness of such systems, however, depends entirely on how the vibrations are structured and calibrated, particularly on regions of the body where the skin is less sensitive. This thesis investigates how to design and fine-tune vibrotactile stimulation in wearable devices so that it communicates information reliably in real-time without causing cognitive fatigue. The forearm is well-suited for such equipment as it does not hinder hand movement and the device can remain nearly unobtrusive. However, the density of mechanoreceptors is lower and spatial perception is poorer there than, for example, in the fingertips, which imposes certain perceptual constraints. Therefore, it is necessary to systematically research how the location, frequency, and temporal patterns of vibration affect how we perceive the vibrations and interpret the messages encoded within them. A custom-built wearable device was designed using voice coil actuators integrated into a flexible textile substrate with 3D-printed enclosures. The device is capable of delivering dynamic, independent, and spatially distributed vibrations. The research employed psychophysical methods to explore and quantify three core dimensions: spatial resolution, frequency effects, and the temporal structure of stimuli. Thesis Objective 1 (TO1) This objective evaluated the minimum spacing required between actuators for users to distinguish between them. The results revealed that a 20 mm spacing yielded the highest accuracy (approximately 90–92%) on both the dorsal and ventral (upper and under) sides of the forearm. Thesis Objective 2 (TO2) This objective investigated how different frequencies (100–250 Hz) and anatomical placements (wrist, mid-forearm, elbow) affected perception. The study showed that frequency alone had little effect, whereas location was crucial; accuracy was higher in areas near landmarks or bone, such as the wrist and elbow. Thesis Objective 3 (TO3) This objective focused on how the timing of stimuli affects perception. Sequential stimulation, where vibration was delivered by one actuator at a time, was compared to simultaneous stimulation, where all relevant actuators were activated at once. The results confirmed that it is significantly easier to distinguish signals delivered sequentially (93.24% accuracy) than those delivered simultaneously (26.15%). Further investigation into inter-stimulus intervals (ISIs) revealed that accuracy is highest when intervals are between 100 and 500 milliseconds. Shorter patterns proved more effective than longer ones, and users remembered the beginning and end of the sequences best. Furthermore, performance improved with practice, demonstrating that users can learn to adapt to such systems over time. These investigations provide a foundation for the design of wearable tactile systems that work efficiently with human perception. The findings are applicable to the development of assistive technologies, sensory substitution devices, silent alerting systems, and even virtual or augmented reality (VR/AR) interfaces. By demonstrating that complex information can be reliably conveyed through structured vibrations on the forearm, this thesis confirms that touch is a viable communication channel in human-computer interaction when other modalities are overloaded.
Life in a cold-water environment: Allometric adaptations of cetaceans in Skjálfandi Bay, Iceland
(University of Iceland, School of Engineering and Natural Sciences, Faculty of Life and Environmental Sciences, 2026-08-28) Glarou, Maria; Marianne H. Rasmussen, Fredrik Christiansen, Takashi Iwata, Arnar Pálsson; Faculty of Life and Environmental Sciences (UI); Líf- og umhverfisvísindadeild (HÍ); School of Engineering and Natural Sciences (UI); Verkfræði- og náttúruvísindasvið (HÍ)
Energy drives all biological processes and constrains how animals acquire, allocate, and expend resources to maintain fitness. This thesis investigates bioenergetic strategies in sympatric cetaceans inhabiting cold subarctic waters. Focusing on five different-sized species in Skjálfandi Bay, Iceland (harbour porpoises, white-beaked dolphins, minke whales, humpback whales, and blue whales), this study combines UAV photogrammetry and bioenergetic modelling to examine how body size influences heat loss (Article I), field metabolic rate (FMR; Article II), and energetic requirements (Article III) under shared environmental conditions. Heat loss scaled predictably with body size, with absolute heat loss increasing and volume-specific heat loss decreasing across species. Smaller cetaceans exhibited higher surface-area-to-volume ratios (SVR) and therefore higher relative heat loss, partly offset by increased blubber thickness and lower thermal conductivity. In contrast, larger species benefited from reduced SVR and lower relative heat loss. FMR also scaled with body size, with absolute FMR increasing and mass-specific FMR decreasing. Species with higher SVR exhibited higher mass-specific FMR, indicating a correlation between thermoregulatory costs and metabolic scaling. Cetacean FMR estimates were generally higher than predictions for similarly sized terrestrial mammals. Energetic requirements and prey consumption followed the same pattern, with larger species having higher absolute but lower mass-specific requirements. Smaller cetaceans required a greater proportion of their body mass in prey, whereas larger species dominated total prey removal at the population level. Overall, the findings of this thesis show that body size is a primary driver of bioenergetic strategies in cetaceans, shaping their life-history traits and ecological roles.
Melanoma dedifferentiation enhances IFNγ responses and reduces cytotoxic T cell activity
(University of Iceland, School of Health Sciences, Faculty of Medicine, 2026-09) Sævarsson, Teitur; Berglind Ósk Einarsdóttir; Faculty of Medicine (UI); Læknadeild (HÍ); School of Health Sciences (UI); Heilbrigðisvísindasvið (HÍ)
Cutaneous melanoma is a deadly skin cancer arising from epidermal melanocytes. A defining feature of melanoma cells is their ability to reversibly dedifferentiate in response to cellular stress, largely through loss of the transcription factor MITF. Dedifferentiation is associated with reduced melanocytic antigen expression, increased migratory and invasive capacity, altered responses to inflammatory stimuli, e.g. leading to increased IFNγ-induced PD-L1 expression. This indicates that melanoma dedifferentiation may influence anti-tumor immune responses and contribute to immune evasion. In this thesis, the effects of melanoma dedifferentiation on immunomodulatory gene expression and melanoma-T cell responses were investigated. The effects of dedifferentiation on immunomodulatory gene expression were assessed by siRNA mediated knockdown of MITF expression in 624Mel cells followed by IFNγ stimulation. Transcriptomic and epigenetic effects were assessed via RNA-seq and ATAC-seq, respectively. IFNγ-induced PD-L1 expression following MITF knockdown was evaluated in 624Mel, SK-MEL-28, A357P, Malme-3M and B16 melanoma cells by qPCR and western blotting. Small molecular inhibitors against the JAK kinases, STAT3 and NFκB and siRNAs targeting STAT1 and IRF1 were used to investigate PD-L1 regulation in 624Mel cells. Public RNA-seq data from patient-derived melanoma cell lines were analyzed to validate the broader relevance of the results. Co-cultures were performed using TCR-redirected T cells and GFP expressing melanoma cell lines at varying differentiation states in live-cell imaging assays. Cytokine secretion in the co-cultures was quantified using a Luminex assay. The results showed that dedifferentiation predisposes melanoma cells to IFNγ signaling through rearrangements in chromatin accessibility, resulting in widespread expression of immunomodulatory genes. PD-L1 expression in dedifferentiated 624Mel cells was mediated via the canonical JAK-STAT1-IRF1 pathway and accompanied by a significant increase in IRF and STAT transcription factor motif accessibility. Co-cultures of TCRredirected T cells and melanoma cell lines suggest that differentiation state does not impair antigen processing and presentation. However, the rate of cytotoxic T cell responses was reduced by IFNγ pre-treatment of either highly differentiated or undifferentiated melanoma cell lines, and by induced dedifferentiation via MITF knockdown. T cell derived secretomes following culture with undifferentiated melanoma cells contained less TNFα, Granzyme B, CXL10, MIF and CCL5 than when cultured with differentiated cells, while containing more PD-L1, IL-8, CD25 and IL-6, suggesting decreased T cell activation. In conclusion, melanoma dedifferentiation may directly mediate immunosuppression.
Holographic Models of Emergent Spacetime
(University of Iceland, School of Engineering and Natural Sciences, Faculty of Physical Sciences, 2026) Mohan, Vyshnav; Lárus Thorlacius; Faculty of Physical Sciences (UI); Raunvísindadeild (HÍ); School of Engineering and Natural Sciences (UI); Verkfræði- og náttúruvísindasvið (HÍ)
Black holes are exceptional laboratories where the apparent incompatibility between gravity and quantum mechanics can be sharpened. In this thesis, quantum features of black holes are probed using the holographic principle, with tools from quantum information and algebraic quantum field theory. Operator algebras provide a natural framework for studying gravity as an emergent phenomenon, and we identify sufficient conditions for the emergence of gravitational dynamics. Going in the opposite direction, quantum gravity effects in an eternal black hole can be modelled by adding certain non-perturbative quantum corrections to its semiclassical operator algebra. This leads to an approximate type I von Neumann algebra whose dimension is equal to the exponential of the Bekenstein-Hawking entropy with logarithmic corrections. Non-perturbative corrections also lead to the late-time saturation of holographic complexity, defined as the volume of a codimension-one extremal surface passing through the black hole interior. A second law associated with this complexity is used to establish a black hole singularity theorem. Non-perturbative corrections may become important during gravitational collapse. Black shells, which have been proposed as an alternative endpoint of collapse in string theory, are studied from a thermodynamic perspective and shown to be thermodynamically favoured over black holes for a range of temperatures.
Quantum fluctuations of non-Lorentzian black holes
(University of Iceland, School of Engineering and Natural Sciences, Faculty of Physical Sciences, 2026-08-26) Harksen, Matthias; Watse Sybesma; Faculty of Physical Sciences (UI); Raunvísindadeild (HÍ); School of Engineering and Natural Sciences (UI); Verkfræði- og náttúruvísindasvið (HÍ)
Ritgerðin fjallar um þyngdarskammtafræði. Hún kannar djúpstæð tengsl sem eru til staðar milli þyngdarfræði eins og henni er lýst í almennu afstæðiskenningunni og hornrækinnar skammtasviðsfræði í einni lægri rúmvídd. Þessi samsvörun nefnist þyngdarfræðileg heilmyndun og hefur ýmsar birtingarmyndir, en ein sú einfaldasta felur í sér að þyngdarfræði í tvívíðu tímarúmi með fastan neikvæðan krappa sé jafngild hornrækinni skammtasviðskenningu sem býr á jaðri þess. Í ritgerðinni er síðan rannsakað hvernig þessi samsvörun og skyldar hugmyndir taka á sig nýja mynd þegar horfið er frá hefðbundnum afstæðilegum samhverfum yfir í óafstæðilegar samhverfur, svo sem Galíleó-, Carroll- og Lifshitz-samhverfur. Meginuppistaða ritgerðarinnar eru þrjár rannsóknagreinar sem fjalla um ólíka þætti óafstæðilegrar þyngdarfræði. Fyrsta greinin fjallar um Carroll-strengjafræði, þar sem athugað er hvernig lýsa megi strengjum í markgildi þar sem hraði ljóss stefnir á núll, sem er viðeigandi lýsing í grennd við sjóndeild svarthola og á jaðri tímarúmsins. Önnur greinin fjallar um skammtafræðilega leiðréttingarliði við varmafræði tvívíðs þinilsviðslíkans sem fæst með víddarlækkun á Lifshitz-svartholi. Þar er markmiðið að varpa ljósi á hvernig varmafræðilegir skammtaeiginleikar svarthola hegða sér þegar horfið er frá hefðbundnum afstæðilegum samhverfum. Þriðja greinin fjallar um óafstæðilegt Galíleó-de Sitter rúm. Þar er leitast við að skilja betur óafstæðilega Newton-Cartan rúmfræði og afleiðingar hennar fyrir heimsfræði þar sem afstæðilegar forsendur eru ekki lengur til staðar í sinni hefðbundnu mynd. Auk greinanna þriggja inniheldur meginmál ritgerðarinnar alþýðlegan inngang. Þar má finna hugleiðingar um það hvers vegna grunnrannsóknir eru mikilvægar fyrir mannkynið og jafnframt stutta kynningu fyrir hinn almenna lesanda á því fræðasviði í háorkueðlisfræði sem greinarnar leggja sitt af mörkum til. Þar að auki fylgir fræðilegur kafli sem byggður er á röð fyrirlestra sem ég sótti í doktorsnáminu mínu. Sá kafli skýrir hið afstæðilega sjónarmið sem greinarnar sjálfar byggja á.
Infallible Iceland? State violence and the struggle for truth, 1968-1998
(University of Iceland, School of Humanities, Faculty of Philosophy, History and Archaeology, 2026-08-10) Brynjarsson, Tryggvi Rúnar; Guðmundur Hálfdanarson; Ragnheiður Kristjánsdóttir; Faculty of Philosophy, History and Archaeology (UI); Deild heimspeki, sagnfræði og fornleifafræði (HÍ); School of Humanities (UI); Hugvísindasvið (HÍ)
In this dissertation, I examine the pattern by which the Icelandic state managed and deflected violence-claims brought against it by aggrieved citizens between 1968 and 1998. Drawing on Michel Foucault’s analytics of power and his conceptualization of regimes of truth, I argue that a particular political logic, what I call the rationality of infallibility, underwrote a recurring repertoire of denial that worked to prevent state violence from being recognized as such. It shows how denial, on Stanley Cohen’s account a structured social and political phenomenon as much as a psychological one, assumed specific historical forms governed by the rationality of infallibility, within a produced horizon that naturalized, in advance, which voices could speak and what narratives could be accepted as true. I trace this rationality and its effects through a microhistorical series following a quartet of outsiders who struggled against it: Haraldur Ómar Vilhelmsson, whose near-fatal assault became, in the hands of authorities, the occasion for his own prosecution; Helgi Hóseasson, whose decade-long struggle to invalidate his baptismal covenant culminated in a nationally televised performance in which he staged state violence; Þorgeir Þorgeirson, the first Icelander to receive a favorable ruling from the European Court of Human Rights after having been censored for writing on state violence; and Sævar Marinó Ciesielski, wrongfully convicted of homicide on the basis of coerced confessions. Each case is reconstructed from previously unused or underused archival sources, and each is read as a high-stakes confrontation that forced the rationality of infallibility to react, and, in reacting, to leave a paper trail of its recurring tactics of denial. The dissertation intervenes both methodologically and politically: by placing these four cases in relation to one another — a coordination systematically foreclosed while the outsiders were alive — it works against the state’s own strategy of individualization, which has kept each grievance contained as an anomalous, and thus manageable, episode. In addition to Foucault and Cohen, the dissertation draws on a range of other interlocutors, developing an original analytical vocabulary to map both the state’s techniques of containment and the outsiders’ methods for contesting them. Together, the microhistorical series constitutes a cumulative stress-test rather than a representative sample; its diagnostic force derives from the clarity with which it exposes the paradox at the heart of the state’s image: an ideal of exceptional innocence that its own violent practice continuously jeopardized. Violence was exercised, as by any modern state, yet it simply could not be publicly owned. This paradox ultimately produced, for the state’s victims, a uniquely cruel outcome: a spectral existence where acknowledgment remained perpetually out of reach.
Gravity, Holography and Deformations
(University of Iceland, School of Engineering and Natural Sciences, Faculty of Physical Sciences, 2026) Nix, Alexia; Friðrik Freyr Gautason (main advisor), Valentina Giangreco M. Puletti (administrative advisor); Faculty of Physical Sciences (UI); Raunvísindadeild (HÍ); School of Engineering and Natural Sciences (UI); Verkfræði- og náttúruvísindasvið (HÍ)
In this dissertation we aim to explore gravity using two different methods, namely precision holography and stress-tensor deformations. From the holographic perspective we achieve this by studying the holographic dual of the half-BPS Wilson loop operator, in a variety of both conformal and non-conformal field theories, which is given by the partition function of a fundamental string or probe M2-brane in the corresponding dual geometry. We do this by focusing on the first subleading correction of the corresponding holographic expansion. This way we provide new quantitative tests of these gauge/gravity dualities, and we further develop the tools that are necessary for such an analysis. On the other hand, we utilize the massive gravity formulation of stress-tensor deformations to establish new connections with various theories of gravity, as well as mathematics. In particular, using this formulation we construct a new d-dimensional deforming operator that extends the findings of previous holographic studies, and makes contact with earlier results of minimal massive gravity. In three dimensions, we study the stress-tensor deformation of a certain seed theory and recover the DBI action of a two-brane in Polyakov form as the deformed action, establishing a new connection to string theory. Finally, restricting our analysis to two dimensions we show how the study of some deformed theories, that satisfy certain properties, can lead to further insights regarding the algebraic properties of special functions.
Irrelevant deformations, relevant masses
(University of Iceland, School of Engineering and Natural Sciences, Faculty of Physical Sciences, 2026) Tsolakidis, Evangelos; Valentina Giangreco and Marotta Puletti; Faculty of Physical Sciences (UI); Raunvísindadeild (HÍ); School of Engineering and Natural Sciences (UI); Verkfræði- og náttúruvísindasvið (HÍ)
The study of stress-tensor deformations is a newly-formed subfield in high energy theoretical physics and one of its main goals is to map out the space of all quantum field theories. Considering their connection to ghost-free massive gravity via the seminal example of TT in two dimensions, we develop a purely gravitational formalism for any deformation of this family in any dimension. Our approach indicates that the effect of the deformation reduces to coupling the undeformed theory with a carefully constructed mass term for the graviton. We employ this idea in various scenarios retrieving and extending known results in string theory and mathematics, ending up in higher dimensions where the dynamics are less explored. There, we establish a concrete connection between a ghost-free massive gravity theory and a holographically inspired deformation providing in parallel a direct derivation of the Polyakov form for branes in static gauge, based on the corresponding structure of the deformation.
Stillbirth in Iceland: Causes and clinicopathological phenotypes
(University of Iceland, School of Health Sciences, Faculty of Medicine, 2026-08-04) Bjarnadóttir, Ragnheiður; Jóhanna Gunnarsdóttir; Faculty of Medicine (UI); Læknadeild (HÍ); School of Health Sciences (UI); Heilbrigðisvísindasvið (HÍ)
Aims: to explore the stillbirth rate (SBR) and examine the etiology of stillbirth in Iceland from 1996-2021 as well as review the placental histopathology. Methods: Clinical information was obtained from medical records of mothers who had stillbirths and their infants (n=395). Infants were divided into groups according to gestational age (GA) at diagnosis of stillbirth: early preterm: ≥22 but < 28 weeks (n=140), late preterm: ≥28 but <37 weeks (n=130) and term: ≥ 37 weeks (n=125). Autopsy records and gross description of placenta were reviewed and microscopic slides re-evaluated and classified according to the Amsterdam placental workshop consensus into four major patterns of placental injury. Primary and associated causes of death were assigned according to the Stockholm classification of stillbirth. The SBR, maternal and fetoplacental characteristics, placental histopathology as well as cause of death were compared between two 13-year periods (1996-2008 and 2009-2021) and between GA groups. Chi-square tests were applied and p-level of 0.05 considered statistically significant. Results: The SBR decreased from 4.10 to 2.88/1000 births (p=0.009) between the former and latter period, but the reduction was limited to stillbirths diagnosed before term. Fewer stillbirths in the latter period were attributed to causes such as infection and placental abruption as well as unknown/unexplained. The most common primary causes of stillbirth were reduced circulation in the umbilical cord (25.6%) and placental insufficiency (25.2%); both increased with advancing GA. Despite no difference in proportion of small for gestational age infants between the two periods, placental weight <10th percentile for GA was significantly more common in the latter period than the earlier (30.3% vs 21.3%, p= 0.002), when a larger proportion of stillbirths was attributed to placental insufficiency (37.0 vs 17.0%, p=0.0002). The stillbirth rate at term was 1.18/1000 term infants with no decrease between the two periods. In stillbirth at term, placentas weighing under the 10th percentile were more common in the latter (43.5 vs 31.7%, p<0.05). Chronic villitis of unknown etiology (VUE) was significantly more often diagnosed in the latter period (40.3 vs,12.7%, p<0.01. Cord complications and placental insufficiency were the most common causes of stillbirth at term as 72% (91/125) of deaths were attributed to these causes, either alone or together. Compared to the earlier period, stillbirth was significantly more often attributed to placental insufficiency (with or without cord complications) in the latter compared to the earlier (56.5% vs. 22.2%, p<0.001). Placental histologic slides were reviewed for 96.4% stillborn singletons and classified into four major patterns of placental injury. Maternal vascular malperfusion (MVM) was diagnosed in 19.0%, fetal vascular malperfusion (FVM) in 31.6%, acute chorioamnionitis (ACA) in 32.2% and VUE in 15.9%. More than one pattern of placental injury was found in 7.7% and none of the major patterns in 27.9% of placentas. A similar proportion of MVM was seen in all GA groups, FVM was more common ≥28 weeks whereas ACA was most frequent <28 weeks and VUE most often diagnosed at term. A higher proportion of maternal vascular malperfusion was found in stillbirths with small for gestational age (SGA) infants than non-SGA (23.0 vs 6.1%) as well as in stillbirths with maternal hypertensive disorder of pregnancy than in stillbirths with a normotensive mother (23.9 vs 11.8%). The umbilical cord was classified as at risk in half (53.8%) of singleton stillbirths, the proportion increased with gestational age (28.9% <28 weeks, 56.0% ≥28 but <37 and 71.7% at term). Hypercoiled, excessively long and wrapped cords were most common. Term stillbirths with cord at risk often also had placental MVM and/or VUE. Conclusions: The SBR decreased in the latter period due to a reduction in preterm stillbirth but the SBR at term was unchanged. Reduced circulation of the umbilical cord and placental insufficiency were the commonest causes of death, both increasing with gestational age. Stillbirth due to infection and placental abruption as well as unexplained stillbirths decreased during the study period whereas deaths attributed to placental insufficiency became more common, reflecting lack of reduction of stillbirth at term in the latter period. Stillbirths with VUE and FVM, as well as umbilical cord at risk, were more common with advancing GA and often without recognized risk factors. Understanding major patterns of placental injury and their correlation to clinical phenotypes of stillbirth is valuable when counselling after stillbirth and planning surveillance of a subsequent pregnancy.
Professional Knowledge in Transition: Police Education Reform and the Reconfiguration of Knowledge in Icelandic Policing
(University of Iceland, School of Education, Faculty of Education and Diversity, 2026-08) Bragason, Olafur Orn; Guðrún Geirsdóttir og Ingólfur Ásgeir Jóhannesson; Faculty of Education and Diversity (UI); Deild menntunar og margbreytileika (HÍ); School of Education (UI); Menntavísindasvið (HÍ)
This doctoral thesis examines how Iceland’s 2016 police education reform reconfigured the forms, value, and legitimacy of professional knowledge as basic police education was shifted from a vocational model to a university-based programme. The reform formed part of a wider professionalisation process with the intention to strengthen the police’s analytical, ethical and communicative competence so that officers are better equipped to respond to an increasingly complex policing environment. Using the analytical perspectives of Shulman, Eraut and Chan, the thesis examines how different forms of knowledge are produced, valued and rendered legitimate across policy, educational and workplace settings. The research comprises four interrelated studies using a multi-method, multi-level design combining qualitative and quantitative approaches: (I) a historical discourse analysis of the policy and legislative texts that framed the reform; (II) an institutional analysis of the implementation of flexible learning and its relationship to workforce needs, access to education, and the system-level legitimation of the reform; (III) a longitudinal study of students’ valuations of professional competence before and after police education reform; and (IV) qualitative interviews with newly graduated officers examining how professional knowledge is enacted and legitimised in practice. The findings suggest that the reform achieved institutional alignment with higher education, but that epistemic and cultural change unfolded more slowly. At the policy level, legitimacy was built on both technocratic and professionalising logics; at the educational level, police students in the university-based programme placed greater value on analytical and relational competence than students in the earlier vocational model; and at the workplace level, academic and experiential knowledge remained only partially integrated. The thesis conceptualises these processes as part of a multi-level knowledge formation in policing and uses the concept of comprehensive competence to describe the cognitive, ethical, and relational dimensions of professional practice. The study contributes to international debates on professional education by portraying how reforms in a small state illuminate the complex interplay between institutional change, learning cultures, and the evolving legitimacy of professional knowledge.
Pathways to Sustainable Eating: Fostering Sustainable Attunement through Commensality and Collective Culinary Creativity
(University of Iceland, School of Social Sciences, Faculty of Sociology, Anthropology and Folkloristics, 2026) Viðarsdóttir, Auður; Valdimar Tr. Hafstein; Faculty of Sociology, Anthropology and Folkloristics (UI); Félagsfræði-, mannfræði- og þjóðfræðideild (HÍ); School of Social Sciences (UI); Félagsvísindasvið (HÍ)
Considerable improvements can be achieved for human and planetary health if everyday food practices are transformed into a sustainable direction, as industrial food systems account for one third of greenhouse gas emissions and contribute to ecosystem degradation. Although the food system is global in scope, changes at local and regional levels are significant to drive its transformation. This PhD dissertation explores the experiences of individuals who have adopted more sustainable or healthier diets (e.g., vegans, vegetarians, flexitarians, and more) in Iceland in recent years with the aim to generate insights to inform further research and policy toward more sustainable and healthier foodways in the country. The research was a part of the transdisciplinary project Sustainable Healthy Diets: Filling the Gaps and Paving the Way for a Sustainable Future, funded by Rannís through the Strategic Research and Development Program 2020–2023. Grounded in ethnology and folkloristics, the analysis emphasizes meaning-making processes in everyday life. The study employs ethnographic methods, including in-depth interviews, participant observation, and a qualitative questionnaire, to investigate the motivations, challenges, and practices associated with dietary transformations among people in Iceland. The dissertation is theoretically informed by more-than-human approaches that bridge the social sciences, humanities, and ecology, and frame eating as an active, embodied engagement that places humans in an ongoing, contingent relation with the world. The study’s findings contribute to research on sustainable dietary transformations, notably by shifting the focus from individual dietary changes to how food and eating can be actively employed to reform human–nature relations and build community. The study identifies creative tinkering as one of the main factors that facilitates and sustains a change toward more sustainable diets—a dynamic process in which new food habits gradually align with practitioners’ core values, bodily needs, and social and natural environments, constituting meaning-making through embodied relations with one’s own body, nature, and other living beings. The main hindering factor in maintaining a new diet, especially in the case of vegans, is the challenging social situations that alternative food practices can create, such as when new food values clash with family traditions or culinary heritage. However, creative tinkering reinforces people’s core values in such a way that it becomes easier for them to overcome and negotiate difficult social situations, share new food values, and maintain their kinship ties through repeated everyday commensality. New values thus become meaningful through human and more-than-human relations, demonstrating the transformative potential of eating as simultaneously a cultural and physiological process. In addition to situating commensality and kinship as relevant analytical tools within dietary sustainability research, the dissertation contributes two original concepts for further application and development in future research: sustainable attunement and collective culinary creativity. Sustainable attunement describes the iterative, embodied process of aligning new values with food habits, bodily needs, and social practices, including the emotional labor of navigating social frictions while remaining true to those values, all of which support the long-term maintenance of a new diet. Collective culinary creativity is a strategy for creating meaningful connections around food and sustainability in local contexts, enhancing the transformative potential of cooking and eating and effectively integrating ethnological methods into transdisciplinary research. Moreover, exploring food-related practices through the conceptual lens of time reveals that the values people build through social relationships often clash with the capitalist, dualistic logic that shapes the global food system and much modern knowledge production. Food’s relational role—as more than a commodity and a means to nurture human and more-thanhuman relations—is frequently undervalued within prevailing systems, which can hinder change as transformations become established largely through social ties. This mismatch must be critically examined to prevent undermining sustainable practices in everyday life. Lastly, this dissertation reflects on the role of ethnology in transdisciplinary research aimed at sustainable food transformations, arguing that ethnologists are particularly well suited to tackle complex socio-ecological challenges and engage with the inherent complexities and contradictions of dietary changes, ultimately facilitating sustainability transformations that treat everyday practices as sites of potential radical change.
Making Sense of Gender in Compulsory School Practices in Iceland
(University of Iceland, School of Education, Faculty of Philosophy, History and Archaeology, 2023-10) Þrastardóttir, Bergljót; Ingólfur Ásgeir Jóhannesson og Steinunn Helga Lárusdóttir; Faculty of Philosophy, History and Archaeology (UI); Deild heimspeki, sagnfræði og fornleifafræði (HÍ); School of Education (UI); Menntavísindasvið (HÍ)
The Act on Equal Status and Equal Rights Irrespective of Gender no. 150/2020 and the current national curriculum for compulsory school education in Iceland emphasise the promotion of gender equality and queer education. However, there are few signs of the enactment of these obligations at the compulsory school level, and research is lacking on the interplay of gender and education. I found this intriguing and decided that it was important to inquire about the gendered aspects of school practices at the compulsory school level, especially since Iceland has been internationally reported to be a feminist paradise. I chose to do the study presented in this thesis on how gender is manifested in school culture and practices in the upper grades of the compulsory school level (grades 8–10, age level 13–16) in one school. The study consists of one data set produced through ethnographic methods. Participant observations were conducted for three months, which gave the researcher an opportunity to interact closely in the field, producing deeper knowledge than before on how actors make sense of gender and how it is performed at the compulsory school level in Iceland. Students and school staff at the upper level of the school participated in group and individual interviews. Rich observational data and additional material was collected to acquire insights into the gendered practices and discourses in the school. This study contributes to and generates new knowledge on how the school and the culture define and (re)produce gender differences, particularly with regards to the available gender positions in schools. The thesis is a compilation of three articles. Article I explores gender dividing practices reflected in different school spaces. Article II explores how students’ gender performativity and conceptualisation of girls as drama supports binary understanding of gender. Article III presents girls claiming discursive space to be able to change the normative gender script in school. Together, these articles give insight into the gender aspects of compulsory school practices in Iceland. Main findings indicate that the school environment favoured dividing practices between boys and girls in both overt and subtle ways, with a relative lack of resistance to the persistent gender division. This was reflected in (cis)heteronormative understanding of gender and gender-based arrangement of different school spaces that reproduced binary gender relations. The understanding of gender categories in school settings had a vital role in positioning students based on their masculine or feminine performativity and reproduced the ideas reflected in societal discourse on gender and social media promoting stereotypical gendered performativity. Claiming discursive space to resist the normative gender script available to students was an individual effort which came with the risk of rejection. The findings further suggest that schools must do better and comply with their duties as to promote gender equality education instead of limiting available gender positions and, thus, students’ freedom to express fluid gender and sexual identities. Schools must also dismantle the myth of Iceland as a gender equal paradise since gender inequalities are still very prominent in schools and will go unnoticed if not addressed.
Animals on display in an Age of Extinction
(University of Iceland, School of Humanities, Faculty of Icelandic and Comparative Cultural Studies, 2026) Kjartansdóttir, Katla; Bryndís Snæbjörnsdóttir; Faculty of Icelandic and Comparative Cultural Studies (UI); Íslensku- og menningardeild (HÍ); School of Humanities (UI); Hugvísindasvið (HÍ)
The examination presented in this PhD dissertation unpacks the significant but changing role of animals, as living beings and in the forms of museum objects, souvenirs, and symbols. The main theoretical frameworks derive from crossdisciplinary, post-humanist perspectives, which have highlighted the agency and role of more-than-humans as important and valuable companion species. In line with these perspectives the aim throughout the dissertation is to draw forth the important role of more-than-humans (including animals and objects) as actants with their own cultural biographies and thing power. In this relation, particular attention is given to visual and material representations of the Atlantic puffin and the extinct great auk within the context of art, tourism and museums. The investigation reveals, for example, how the Atlantic puffin as a living animal, material object and visual symbol has increasingly been activated within the context of Arctic tourism in Iceland. Another aim of the dissertation is to shed light on how current human induced environmental challenges, such as climate change and animal extinction, have impacted and changed our human/more-than-human relations. Furthermore, how these changes are met and engaged with through visual and material representations within the context of art, tourism, and museums. The dissertation contributes to the emerging field of multi-species studies, across disciplines, which include animal studies, post-humanist studies and more-than-human studies. The four case studies shed light on the complexities, challenges, and politics of representing human/more-than-human entanglements in our present epoch, frequently described as the Age of Extinction. An epoch, which demands continual challenging of traditional, dualistic boundaries and divisions to raise fruitful discussions and, not least, to discover collective solutions. Throughout the dissertation museums, and other cultural spaces, are regarded as important arenas where discussions and critical reflections can take place on urgent dark ecological matters of our times, such as rapid animal extinction.
A Novel Role of the MITF-A Isoform in Maintaining Genomic Stability
(University of Iceland, School of Health Sciences, Faculty of Medicine, 2026-03-04) Venkatesh, Thejus; Stefán Sigurðsson; Faculty of Medicine (UI); Læknadeild (HÍ); School of Health Sciences (UI); Heilbrigðisvísindasvið (HÍ)
The genome of all living cells is susceptible to various intra- and extracellular events that can compromise its stability. This genomic stability is crucial for the normal function of all cells, and failure to preserve genome integrity can lead to cancer and other diseases. In the event of DNA damage, cells activate the so-called DNA Damage Response to initiate DNA repair. Replication stress can also cause genomic instability. Replication stress interrupts the DNA replication process by stalling the active replication fork. If there is prolonged replication stress, it leads to genomic instability, which can result in DNA damage, chromosomal abnormalities, and mutations. MITF is a transcription factor best known for its roles in melanocyte biology and melanoma, but its function in genome maintenance remains incompletely understood. While most studies have focused on the MITF-M isoform, the roles of other isoforms remain largely unexplored. Interestingly, many non-melanocytic cells predominantly express the MITF-A isoform. Data presented in this project show that MITFA is expressed in most tissues, including cancer tissues, and may function as a genome maintenance protein. In this study, we use the osteosarcoma cell line U2OS to uncover the non-melanocyte-specific role of MITF. We found that MITF depletion leads to TP53 accumulation, P21 expression, increased 53BP1 nuclear bodies, and high fork speed, suggesting a protective role in S phase, thus maintaining genomic stability. Differentially expressed genes upon MITF-A isoform knockdown show downregulation of genes associated with DNA replication and DNA repair. Mass spectrometry reveals that MITF-A shows increased interaction with proteins involved in DNA replication and repair, including RPA and PARP1, compared to MITF-M. Notably, data from single-molecule C-trap optical tweezer experiments show that MITF-A, but not MITF-M, stably binds RPA-coated singlestranded DNA. Replication dynamics revealed that MITF-A depletion led to an increase in replication fork speed, which is associated with reduced PARylation. Collectively, this study highlights MITF-A’s role in DNA replication and in maintaining genomic stability.
In Situ LIBS Analysis of Oxidation, Vaporization, and Phase Transformations in Molten Aluminum Alloys
(University of Iceland, School of Engineering and Natural Sciences, Faculty of Physical Sciences, 2026-06-24) Radsson, Mani Thor; Snorri Þorgeir Ingvarsson; Faculty of Physical Sciences (UI); Raunvísindadeild (HÍ); School of Engineering and Natural Sciences (UI); Verkfræði- og náttúruvísindasvið (HÍ)
This thesis demonstrates how in‑situ Laser‑Induced Breakdown Spectroscopy (LIBS) can be used to probe thermodynamic and kinetic phenomena in molten aluminum alloys. The results show that LIBS not only provides rapid compositional analysis but also captures vapor–liquid equilibria, oxidation behavior, and phase‑transformation dynamics in molten metal. In Al–Mg alloys, the Mg LIBS signal was found to be influenced by vapor‑phase emission, causing an exponential increase in apparent Mg concentration with temperature. Arrhenius analysis showed that this trend follows the enthalpy of Mg vaporization, confirming that LIBS directly reflects Mg vapor–liquid equilibrium. Alloying additions revealed varying degrees of thermodynamic interactions: Si, Zn, and Sn in 1-3 wt% concentrations moderately affected Mg activity, while alloying with Be, Ca, and Sr significantly reduced the temperature-dependent Mg contribution at only 0.01 wt% additions, in agreement with other studies on the influence of these group-II elements on the oxidation of Mg-containing melts. For Li‑containing alloys, the LIBS analysis showed strong signal saturation due to rapid surface oxidation and the formation of Li‑rich surface films. Time‑dependent measurements demonstrated that the Li concentration decays exponentially in the melt, with decay time increasing linearly with Mg concentration, suggesting that Mg-containing oxides have a partial blocking effect on Li removal from the melt. In primary aluminum, Li additions were shown to enhance the loss of Mg, Ca, and Sr from the melt. In Al–Ti and Al–Zr alloys, LIBS was successfully used to map liquid–solid equilibria and track real‑time formation of Al₃Ti and Al₃Zr. Measured liquidus lines agreed with thermodynamic predictions, while experiments at different cooling rates revealed different degrees of nucleation undercooling for Al₃Ti and Al₃Zr phases. Silicon additions were shown to reduce undercooling in Al–Zr alloys and affect the morphology of Al₃Zr in the solidified alloy. Overall, the work shows that molten-metal LIBS analysis is a powerful tool for studying vaporization, oxidation, and intermetallic phase formation in molten alloys, offering unique opportunities for real-time analysis in metallurgical research and industrial process monitoring.
Scribes and Scribal Practice in Fifteenth-Century Iceland: A Study on the Evolution of Script and Language.
(University of Iceland, School of Humanities, Faculty of Icelandic and Comparative Cultural Studies, 2026-06-19) Pagani, Roberto Luigi; Haraldur Bernharðsson; Faculty of Icelandic and Comparative Cultural Studies (UI); Íslensku- og menningardeild (HÍ); School of Humanities (UI); Hugvísindasvið (HÍ)
This dissertation investigates Icelandic scribal and linguistic practices during the socalled “long” fifteenth century, roughly spanning from the late fourteenth century to the early sixteenth. The period has traditionally been regarded as one of stagnation in both language and script, yet such an assessment has rarely been tested through systematic analysis. The present study re-examines this assumption by tracing selected palaeographic and orthographic developments across a corpus of fifty scribal hands drawn from manuscripts dated between c. 1375 and c. 1525. Three palaeographic and seven linguistic features were selected on the basis of their frequency, diagnostic value, and chronological sensitivity. These include, among others, the distribution of forms of the letter “a”, of the tall “s” and of the “r” rotunda on the one hand, and on the other the fricativisation of unstressed wordfinal k, the diphthongisation of e before ng and that of é, the drop of intervocalic g before i/j, the u-epenthesis, and the orthographic representation of palatal consonants. Data were gathered through systematic random sampling of images of manuscript texts and converted into quantitative tables allowing comparison between conservative and innovative forms. The results demonstrate that the fifteenth century was not a static period but rather one characterised by gradual and uneven change. Certain features reveal clear chronological trajectories, while others display persistent coexistence of competing forms. When the individual profiles of scribal hands are compared, no coherent clusters emerge that could correspond to geographical or institutional affiliations, suggesting a highly individualised scribal practice which challenges the notion of “scribal schools” or “scribal milieu”. The combination of palaeographic and linguistic data thus provides a more nuanced picture of late-medieval Icelandic manuscript culture. Far from representing a period of decline, the “long” fifteenth century appears as a dynamic phase of transition, bridging the classical and early modern stages of Icelandic writing. Not least, the findings offer a basis for refining the dating of broadly-dated manuscripts and for reassessing the evolution of Icelandic orthography and script.
The non-antibacterial mechanism of action of azithromycin and other macrolides in respiratory epithelium
(University of Iceland, School of Health Sciences, Faculty of Medicine, 2026-06) Asbjarnarson , Arni; Þórarinn Guðjónsson; Faculty of Medicine (UI); Læknadeild (HÍ); School of Health Sciences (UI); Heilbrigðisvísindasvið (HÍ)
Epithelial barrier failure is a common denominator in multiple acute and chronic respiratory diseases. The respiratory epithelial barrier presents the first line of defence against infectious agents and other particulate matter; continuous exposure of epithelial cells results in molecular and phenotypic changes that evoke conditions such as inflammation, fibrosis, and epithelial-to-mesenchymal transition (EMT). Macrolide antibiotics are known for their off-label use in treatments of chronic respiratory diseases (CRD), primarily due to their anti-inflammatory and immunomodulatory effects. Azithromycin (AZM), in particular, has been recognized for its use in decreasing the frequency of CRD exacerbations. Our research group has previously shown that AZM maintains bronchial epithelial integrity in air-liquid interface (ALI) cell culture conditions. However, the mechanisms underlying this effect are not completely known. The aim of this thesis is to understand the non-antibiotic mechanism of action of macrolides, particularly AZM, in modulation of barrier integrity and metabolism of bronchial epithelial cells. In paper I, the effects of different macrolides (AZM, clarithromycin, erythromycin, roxithromycin and solithromycin) on gene expression and epithelial integrity in ALI culture were compared. AZM treatment, when compared to other macrolides, drastically enhanced barrier integrity, induced phospholipid retention and vesicle build-up. Analysis of gene sequencing data sets revealed AZM treatment distinctly enriched several gene sets, most notably increasing the expression of genes related to keratinocyte differentiation, establishment of skin barrier and downregulation of EMT pathways. The focus of Paper II was the potential role of AZM in EMT. AZM inhibited TGF-β1-induced upregulation of SNAI1, N-cadherin and vimentin, key features of EMT. Furthermore, AZM reduced the expression of caveolin-1 that has previously been linked to EMT. The data presented in Paper II report a potential mechanism by which AZM inhibits EMT via depletion of caveolin-1 and cholesterol from the cell membrane through their transport to a perinuclear location. The aim of Paper III was to expand on and compare the effects of the same macrolide antibiotics as those examined in Paper I, but with a focus on oxidative phosphorylation and mitochondrial function. Macrolide treatment indirectly decreased mitochondrial respiration and lowered protein levels of electron transport chain proteins. However, only AZM treatment caused an increase in reactive oxygen species at 72 hours post treatment along with a downstream increase in lipid peroxidation. The antioxidant pathway of KEAP1/NRF2 was activated and gene expression data from longer treatments (14 and 21 days) in ALI culture revealed that AZM initiated mitochondrial dynamic and protective pathways through mitohormesis. In Paper IV, AZM was compared to a nonantibacterial derivative of AZM (EP395) to determine whether the effects of AZM are distinct from its antimicrobial activity. It was shown that EP395 retained the barrier integrity enhancing capabilities of AZM along with positive enrichment of the same gene sets found to be uniquely affected by AZM treatment, indicating that these effects are distinct from the antibacterial activity. Papers V and VI focused on ventilatorinduced lung injury (VILI) in a rodent model where it was investigated whether macrolides ameliorate the negative effects caused by mechanical ventilation. It was shown that barrier failure correlated with increased expression of the pro-inflammatory cytokine IL-6 and higher tidal volumes. Furthermore, increased oxidative stress and phenotypic changes in mitochondria were observed. Finally, we reported that AZM and EP317, another derivative of AZM with reduced antibacterial activity, ameliorated pulmonary oedema, enhanced barrier integrity, and attenuated inflammatory responses caused by ventilation. Collectively, I have shown that AZM has greater effects on bronchial epithelial barrier integrity than other macrolides, that it inhibits EMT and fortifies mitochondrial resilience. I propose possible mechanistic pathways involved in the beneficial effects of AZM treatment, while recognising that additional research is needed to fully uncover AZM’s involvement in the discussed pathways.
BDPA radicals for DNP-NMR and a new method for RNA spin-labeling
(University of Iceland, School of Engineering and Natural Sciences, Faculty of Physical Sciences, 2026-06-16) Ahmad, Iram; Snorri Þór Sigurðsson; Faculty of Physical Sciences (UI); Raunvísindadeild (HÍ); School of Engineering and Natural Sciences (UI); Verkfræði- og náttúruvísindasvið (HÍ)
Dynamic nuclear polarization (DNP) is a powerful approach for overcoming the low sensitivity of nuclear magnetic resonance (NMR) spectroscopy and has extensive applications in the study of both materials and biological systems. Electron paramagnetic resonance (EPR) and fluorescence spectroscopy are highly important complementary techniques and are particularly valuable for studying nucleic acid structure and dynamics. The broader application of these methods, however, depends on the availability of suitable polarizing agents and site-specific spectroscopic probes, respectively. This thesis focuses on the development of 1,3 bisdiphenylene-2-phenylallyl (BDPA)-based polarizing agents for DNP-NMR and a facile spin labeling strategy for nucleic acids. The first part describes the development of tailored BDPA derivatives for high-field DNPNMR. The synthesis of the key precursor, tetrabromo BDPA, was first optimized. A tetraazide-BDPA building block was subsequently prepared, enabling conjugation to a variety of alkynes via copper-catalyzed azide-alkyne cycloaddition. Using this strategy, four BDPA derivatives with varied polarity, size, and steric shielding were prepared. Of these, a BDPA-dendrimer derivative exhibited enhanced persistence and superior DNP performance, achieving the highest liquid-state DNP enhancement reported to date in viscous solutions. The second part describes a noncovalent RNA spin labeling strategy based on helical stacking of small RNA hairpins, containing the rigid spin label Çm, on RNA duplexes. Complementary overhangs promoted efficient hairpin-duplex stacking, monitored by EPR spectroscopy. In addition, collaborative projects involving incorporation of rigid and semirigid spin labels and fluorophores in nucleic acids to study their structure, dynamics and interactions with proteins using EPR and fluorescence spectroscopies, are recounted.

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