Opin vísindi
Opin vísindi er varðveislusafn vísindaefnis og doktorsritgerða í opnum aðgangi á vegum íslenskra háskóla og Landsbókasafns Íslands - Háskólabókasafns.
Opinn aðgangur að rannsóknaniðurstöðum er í samræmi við 10. gr. laga nr. 3/2003 um opinberan stuðning við vísindarannsóknir sem og kröfur innlendra og erlendra rannsóknasjóða. Markmiðið með opnum aðgangi er að niðurstöður rannsókna séu aðgengilegar sem flestum óhindrað og án endurgjalds á rafrænu formi. Vistun í varðveislusafninu er varanleg og ætlað að tryggja aðgang að vísindaefni íslenskra háskóla í opnum aðgangi um ókomna tíð. Varðveislusafnið Opin vísindi er tengt við rannsóknagáttina IRIS og rannsóknaniðurstöður í opnum aðgangi sem eru skráðar í IRIS eru um leið vistaðar og gerðar aðgengilegar til framtíðar í varðveislusafninu. Með því að safna þessu efni saman í eitt safn verður aðgangur að því einfaldur og þægilegur fyrir alla sem vilja kynna sér það og geta þannig notið þess öfluga vísindastarfs sem fram fer í háskólum landsins.
Varðveislusafnið er OpenAIRE / OpenAIREplus samhæft og samrýmist kröfum sem gerðar eru um birtingu rannsóknaniðurstaðna úr verkefnum sem styrkt eru úr evrópsku rannsóknaáætlununum FP7 og H2020.
Varðveislusafnið notar opna hugbúnaðinn DSpace.
Opinn aðgangur að rannsóknaniðurstöðum er í samræmi við 10. gr. laga nr. 3/2003 um opinberan stuðning við vísindarannsóknir sem og kröfur innlendra og erlendra rannsóknasjóða. Markmiðið með opnum aðgangi er að niðurstöður rannsókna séu aðgengilegar sem flestum óhindrað og án endurgjalds á rafrænu formi. Vistun í varðveislusafninu er varanleg og ætlað að tryggja aðgang að vísindaefni íslenskra háskóla í opnum aðgangi um ókomna tíð. Varðveislusafnið Opin vísindi er tengt við rannsóknagáttina IRIS og rannsóknaniðurstöður í opnum aðgangi sem eru skráðar í IRIS eru um leið vistaðar og gerðar aðgengilegar til framtíðar í varðveislusafninu. Með því að safna þessu efni saman í eitt safn verður aðgangur að því einfaldur og þægilegur fyrir alla sem vilja kynna sér það og geta þannig notið þess öfluga vísindastarfs sem fram fer í háskólum landsins.
Varðveislusafnið er OpenAIRE / OpenAIREplus samhæft og samrýmist kröfum sem gerðar eru um birtingu rannsóknaniðurstaðna úr verkefnum sem styrkt eru úr evrópsku rannsóknaáætlununum FP7 og H2020.
Varðveislusafnið notar opna hugbúnaðinn DSpace.
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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.
Development of AsymPol- and bTurea-Derived Bis-Nitroxides for DNP-Enhanced NMR in Biological Systems
(University of Iceland, School of Engineering and Natural Sciences, Faculty of Physical Sciences, 2026-06-16) Wilson, Ancy Trisha; 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)-enhanced solid-state nuclear magnetic resonance (NMR) spectroscopy has emerged as a powerful technique to unravel complex biomolecular structures at atomistic resolution. DNP serves to overcome the inherent insensitivity of NMR by the polarization transfer from unpaired electrons to nuclei of interest under microwave irradiation. The sensitivity gain conferred by DNP enables the detection of biomolecules at their physiological concentration. Nitroxide biradicals have shown to be excellent polarizing agents at 9.4 T and 14.1 T, prompting our interest in utilizing them to investigate complex systems via DNP-NMR. However, their broader applicability is limited by several factors, including synthetic challenges, lack of specificity, poor aqueous solubility, and rapid reduction in a reducing environment. This thesis describes the development of synthetic strategies for nitroxide-based biradicals to address these limitations. Firstly, a series of AsymPol-derivatives, including an isothiocyanate, a tetrazine, a maleimide, a cholesterolbased tripod, and an azide, was synthesized to enable targeting of diverse systems ranging from biomolecules to materials. These radicals enabled targeted DNP, which allows selective enhancement of signals from specific sites. Secondly, bTurea-derived bcTCOOKs and bcTmols were developed as readily accessible and water-soluble derivatives to address synthetic limitations associated with highly performing bis-nitroxide biradicals. Among these, bcTCOOK-M2 was the highest yielding and exhibited particularly high DNP sensitivity. Finally, a synthetic strategy was established for highly water-soluble, reductionresistant nitroxide radicals (43 and 44) for in-cell DNP applications. Their stability in the presence of ascorbic acid was evaluated and compared with known radicals; however, they did not exhibit sufficient stability under reductive conditions.
An infant diet score, BMI and asthma medication in childhood; Population-based evidence from the Icelandic Maternal and Child Health Study (ICE-MCH).
(University of Iceland, School of Health Sciences, Faculty of Food Science and Nutrition, 2026-06) Jonsdottir, Jenny; Birna Þórisdóttir og Inga Þórsdóttir; Faculty of Food Science and Nutrition (UI); Matvæla- og næringarfræðideild (HÍ); School of Health Sciences (UI); Heilbrigðisvísindasvið (HÍ)
Background and aim: Infant nutrition is a key determinant of both short- and long-term health. However, few population-based studies have integrated information on breastfeeding and complementary feeding into a comprehensive measure and examined its associations with childhood health outcomes. The aim of this doctoral thesis, “An Infant Diet Score, BMI, and Asthma Medication in Childhood: PopulationBased Evidence from the Icelandic Maternal and Child Health Study (ICE-MCH)”, was to investigate associations between infant nutrition, childhood BMI, and pediatric asthma medication use.
Materials and methods: The ICE-MCH study includes data from electronic health registers for children born in Iceland between 2009 and 2015, forming a nationwide population-based cohort (N=30,623). Paper I of the thesis describes infant nutrition from a few weeks after birth until one year of age. Nutritional variables were obtained from records completed by primary healthcare nurses during nine routine visits with the infant and their caregiver, most often the mother. A composite measure of infant nutrition quality, the Infant Diet Score (IDS), was derived from these data, based on Icelandic infant feeding recommendations and existing infant diet scores. The IDS comprised six components: duration of exclusive and any breastfeeding, age at introduction of cow’s milk and complementary foods, an estimate of dietary variety, and use of vitamin D supplementation. Higher scores indicated greater adherence to infant nutrition guidelines. Associations between the IDS and growth outcomes were examined, with a focus on the international BMI-for-age z-scores during infancy and toddlerhood (12 and 18 months; Paper I) and childhood (2.5, 4, 6, and 9 years; Paper II). Associations between the IDS and asthma medication between ages 1 and 7 years were investigated using data from the Icelandic Prescription Medicines Register. The outcome was defined as two or more dispensations of asthma medication within a 12- month period (Paper III). In addition to descriptive analyses, linear and logistic regression models were applied, both unadjusted and adjusted for potential confounders.
Results: Due to its composite nature, the IDS was calculated for the subset of children with complete nutritional data across all nine visits from 0 to 12 months of age (n = 12,848). Findings from Papers I–III showed that greater adherence to infant nutrition guidelines, reflected by a higher IDS, was associated with more favorable BMI trajectories up to 9 years of age and a lower risk of asthma medication use up to age 7. Children in the lowest IDS quintiles had higher odds of overweight and obesity (based on international definitions) at 12 and 18 months and at 6 and 9 years compared with those in the highest quintile, after adjustment for relevant maternal and birth characteristics. When examining individual components of the score, most consistently shorter duration of exclusive and any breastfeeding were associated with less favorable growth outcomes. Shorter duration of exclusive and any breastfeeding, lower use of vitamin D supplementation, and lower overall IDS were consistently associated with increased odds of having two or more asthma medication dispensations within a 12- month period between ages 1 and 7 years.
Conclusions: This study demonstrates that the Infant Diet Score, a composite measure capturing overall diet quality during the first year of life, is a valuable population-based indicator of infant nutrition that can be applied in research on health outcomes. Lower adherence to infant nutrition guidelines in the first year of life is associated with less favorable growth trajectories and increased asthma medication dispensation in childhood. These findings suggest that infant nutrition is an early-life exposure that is important for subsequent child health.
Réttindi og þátttaka barna : Samstarfsverkefni í leikskólum, á yngsta stigi grunnskóla og á frístundaheimilum Hafnarfjarðarbæjar
(RannUng, 2026-06-09) Hreinsdóttir, Anna Magnea; Björnsdóttir, Margrét Sigríður; Ólafsdóttir, Sara Margrét; Deild kennslu- og menntunarfræði
Skýrslan fjallar um samstarfsverkefnið Réttindi og þátttaka barna sem RannUng og Mennta- og lýðheilsusvið Hafnarfjarðarbæjar unnu með leikskólum, yngsta stigi grunnskóla og frístundaheimilum á árunum 2023–2026. Markmið verkefnisins var að innleiða Barnasáttmála Sameinuðu þjóðanna markvisst í daglegt starf, efla þekkingu starfsfólks, barna og foreldra á réttindum barna og skapa aðstæður þar sem börn geta haft raunveruleg áhrif á eigið skóla- og frístundalíf. Verkefnið byggði á starfendarannsóknum, fræðslu, sameiginlegum fundum, rýnihópaviðtölum og þróun verkefna á hverri starfsstöð, meðal annars um lýðræði í hópastarfi, áhugasviðsval, bókasafn, matartíma og valkerfi í frístund. Niðurstöður sýna að þekking starfsfólks á réttindum barna jókst og varð víða samofin daglegum starfsháttum. Viðhorf til barna þróuðust frá því að líta á þau sem þátttakendur innan fyrirfram ákveðins ramma yfir í að viðurkenna þau sem virka gerendur með eigin sjónarmið og áhrif. Dæmin sýna að þátttaka verður merkingarbær þegar hugmyndir barna eru teknar áfram og leiða til sýnilegra breytinga. Helstu áskoranir tengdust tíma, mannafla, forföllum, ólíkum þörfum barna og togstreitu milli verndar og sjálfræðis. Verkefnið sýnir að innleiðing Barnasáttmálans krefst ígrundunar, skýrrar ábyrgðar, stuðnings stjórnenda og þess að réttindi barna verði hluti af starfsmenningu en ekki viðbótarverkefni. Það veitir jafnframt öðrum starfsstöðvum gagnlegan vegvísi til sambærilegrar þróunar og innleiðingar.
On seismic behavior and vulnerability of building structures: Dynamic identification, condition assessment, and fragility modeling
(University of Iceland, School of Engineering and Natural Sciences, Faculty of Civil and Environmental Engineering, 2026-06-10) Gautam, Dipendra; Rajesh Rupakhety, Bjarni Bessason, Hugo Rodrigues; Faculty of Civil and Environmental Engineering (UI); Umhverfis- og byggingarverkfræðideild (HÍ); School of Engineering and Natural Sciences (UI); Verkfræði- og náttúruvísindasvið (HÍ)
Structures undergo various changes during their service life due to deterioration or external loading. These changes are the keys to design, assess, and predict structural behavior. The three pillars of structural engineering are the most governing factors to justify safety, serviceability, functionality, and operability of structures, considering forms and functions. Although independently extensively studied, coordinated efforts have not been widely practiced in structural engineering, starting from characterization to condition assessment and finally probabilistic response depiction. Aiming at coordinated dissemination of the three pillars, the present study performs system identification based modal characterization to develop period-height relationships and condition assessment under no external loading, structure undergoing deterioration, changed state of structure due to extreme loading, changed state of structure due to construction progression, and strengthened structures following various states of damage. Furthermore, many sets of seismic fragility functions have been developed for low-rise RC buildings, considering global and component level performance using empirical data. This study covers RC and stone and brick masonry buildings for dynamic identification, condition assessment, and seismic vulnerability modeling. Experimental and empirical approaches have been deployed to estimate dynamic characteristics as structural performance signatures, evolution of dynamic characteristics as signatures of changed state of the structures, and probabilistic models as signatures to quantify the exceedance probability of particular damage level in buildings and components under seismic excitation. Bayesian modeling based formulation is adopted through MCMC using Metropolis-Hastings sampling to derive period-height relationships and fragility functions. Subsequently, posterior parameter uncertainties have also been characterized.
Error fetching top-level communities