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Refining marine polysaccharides and their immunomodulatory effects
(University of Iceland, School of Health Sciences, Faculty of Food Science and Nutrition, 2025-10-02) Daugbjerg Christensen, Monica; Guðmundur Óli Hreggviðsson; Matvæla- og næringarfræðideild (HÍ); Faculty of Food Science and Nutrition (UI); Heilbrigðisvísindasvið (HÍ); School of Health Sciences (UI)
Brown seaweed is a rich source of structurally diverse polysaccharides with promising bioactive properties. This study investigated in four ways how enzymatic refining can modify marine polysaccharides and influence their immunomodulatory effects. 1) A novel sulfatase, SulA1, cloned from a marine Arthrobacter strain, was characterized, and shown to selectively act on the chondroitin sulfate monosaccharide N-Acetyl-D-galactosamine-4-sulfate. This introduced the possibilities for the use of SulA1 in targeted desulfation strategies to alter bioactivity of targeted molecules. 2) Laminarin from three brown seaweed species (Laminaria digitata, L. hyperborea, and Saccharina latissima) was extracted and enzymatically modified. The laminarin derivatives were structurally analysed and found to distinctly regulate dendritic cell activity depending on their molecular size and branching pattern. These data suggest that different laminarin derivatives may have different therapeutic applications within the immune system. 3) Fucoidan from S. latissima was enzymatically refined into defined molecular weight fractions. The low molecular weight fucoidan fraction significantly suppressed the secretion of the pro-inflammatory cytokine by dendritic cells, indicating potential therapeutic applications against inflammatory diseases. 4) Two enzymatically generated alginate oligosaccharide fractions, enhanced cytokines secretion by dendritic cells and promoted Th1 responses in co-cultures with T cells. These findings highlight distinct immunomodulatory properties of alginate oligosaccharides with potential therapeutic relevance in inducing inflammatory responses, e.g. as adjuvants or in cancer treatment. Collectively, these results demonstrate that targeted enzymatic modifications can reshape the immunomodulatory activity of marine-derived polysaccharides, positioning them as promising candidates for therapeutic development. At the same time, this strategy enhances the efficient use of seaweed biomass and supports the creation of sustainable, high-value products with potential applications in pharmaceuticals and nutraceuticals.
Verk
Impact of anticoagulation and immunosuppressive drugs on the prognosis of patients with colorectal cancer: a population-based study
(University of Iceland, School of Health Sciences, Faculty of Medicine, 2025-10-01) Agustsson, Arnar; Einar Stefán Björnsson; Læknadeild (HÍ); Faculty of Medicine (UI); Heilbrigðisvísindasvið (HÍ); School of Health Sciences (UI)
Nýgengi ristil- og endaþarmskrabbameina fer vaxandi og eru þau ein algengasta orsök andláta vegna krabbameina. Oftast greinast þau vegna blæðingartengdra einkenna frá meltingarvegi og blóðþynningarlyf hafa verið tengd við auknar líkur á blæðingum frá þessum krabbameinum. Hins vegar er það ekki rannsakað hvaða áhrif blóðþynningarlyf geti haft á orsakir meltingavegsblæðinga, hvort þau auki greiningar þessara krabbameina og geti leitt til snemmgreiningar. Engar rannsóknir hafa kannað hvort stigun ristilkrabbameinsins eða lifun einstaklinga á blóðþynningu sé frábrugðin við almennt þýði. Þá hafa rannsóknir á áhrifum hjartamagnýl á lifun einstaklinga ekki borið saman um hvort hjartanagnýl sé verndandi og þá ekki með hvaða hætti það væri verndandi. Hvorki sterar né bólgueyðandi gigtarlyf (e. DMARDs) hafa verið rannsökuð hvort þau geti haft áhrif á lifun einstaklinga með ristil- og endaþarmskrabbamein, en þau hafa bæði sýnt bæta lifun í há áhættu sjúklingahópum. Efni og aðferðir: Allar fjórar rannsóknirnar voru lýðgrundaðar afturskyggnar rannsóknir sem byggðu á gagnagrunnum. Fyrsta rannsóknin nýtti blóðþynningargagnagrunn til að kanna orsakir meltingarvegsblæðinga frá 2014-2019. Hinar þrjár rannsóknirnar byggðu á gagnagrunni yfir alla sjúklinga sem greindust með ristil- og endaþarmskrabbamein frá 2000- 2019 á Íslandi og báru saman lyfjanotkun fyrir greiningu og útkomur vegna krabbameins. Lyfjaupplýsingum var safnað beint úr uppflettingum sjúkraskráa fyrir blóðþynningarlyf og hjartamagnýl, og svo fengust upplýsingar um stera og bólgueyðandi gigtarlyf frá Lyfjagagnagrunni Landlæknis. Niðurstöður: Í fyrsta hluta verkefnisins reyndust 12.005 einstaklingar vera á blóðþynningu og af þeim greindust 752 með meltingarvegsblæðingar, þar af 273 (36%) sem höfðu bráða efri meltingarvegsblæðingu og 391 (52%) bráða neðri. Bæði ristil- og endaþarmskrabbamein (OR 3.7, 95% CI: 2.0 – 7.0, p< 0.001). Sjúklingar á hjartamagnýli höfðu svipaða heildarlifun en betri krabbameinssértæka lifun (HR: 0.79, 95% CI (0.65 – 0.95), p= 0.01). Í fjórða hluta voru 2388 sjúklingar og þar af 816 (34%) sem tóku stera og 91 (3.8%) sem tóku bólgueyðandi gigtarlyf. Sjúklingar sem tóku stera voru að jafnaði eldri og oftar kvenkyns. Sterahópurinn hafði svipaða heildarlifun, klára en ómarktæka fylgni við verri krabbameinssértæka lifun (HR: 1.15, 95% CI (0.96 – 1.38), p= 0.12) og verri sjúkdómsfría lifun (HR: 1.14, 95% CI (1.03 – 1.27), p= 0.02) miðað við samanburðarhópinn. Sjúklingar sem notuðu bólgueyðandi gigtarlyf voru af svipuðum aldri, kyni og með svipaða fylgisjúkdómabyrði og samanburðarhópurinn en voru oftar með krabbamein á stigi I (32% vs 21%, p= 0.02). Hópurinn á bólgueyðandi gigtarlyfjum hafði sambærilega heildarlifun og samanburðarhópurinn og krabbameinssértæka lifun. Ályktun: Niðurstöður þessara rannsókna renna frekari stoðum undir þá kenningu að blóðþynningarlyf geti leitt til snemmgreiningar einstaklinga með ristil- og endaþarmskrabbamein. Blóðþynningarlyf tengdust oftar blæðingartengdum einkennum sem orsökuðust af ristil- og endaþarmskrabbameini og blóðþynningarhópurinn hafði betri krabbameinssértæka lifun. Þetta undirstrikar mikilvægi þess að einstaklingar á blóðþynningu séu undir vökulu eftirliti. Hjartamagnýl tengdist betri krabbameinssértækri lifun, mögulega með því að draga úr eða hindra meinvörp. Steranotkun tengdist verri sjúkdómsfrírri lifun og með fylgi við verri krabbameinssértæka lifun. Bólgueyðandi gigtarlyf tengdust hærra hlutfalli sjúklinga á stigi I, en virtust ekki hafa nein teljandi áhrif á lifun. Niðurstöður rannsóknarinnar á sterum og bólgueyðandi gigtarlyfjum gefa tilefni til frekari rannsókna á þessu sviði til að kanna til hlýtar áhrif þeirra á útkomur einstaklinga með ristil- og endaþarmskrabbamein.
Verk
Papierforschung im Dienste der Buchgeschichte: Einbände des 18. Jahrhunderts in der Handschriftensammlung Árni Magnússons
(International Association of Paper Historians, 2025-03-01) Stegmann, Beeke
Many different bindings are preserved in the manuscript collection once owned by the Icelander Árni Magnússon (1663-1730). Especially with regard to the eighteenth-century bindings, only a few types have hitherto been described and dated. The present contribution shows that watermark research – in particular the analysis of the paper used in the bindings’ endleaves – can help distinguish more styles and provide descriptions and at least rough datings for four additional ones. A single bookbinder could produce several different types of bindings, but it is clear that the book binder Bertel Wolck used various old paper for his bindings, possibly leftover sheets that still circulated in Copenhagen in the 1720s.
Verk
Blue whiting in Icelandic waters: migration, residency, and population connectivity
(Inter-Research, 2025-09-18) Lee, Brendon; Ólafsdóttir, Anna H.; Post, Søren; Randhawa, Haseeb S.; Líf- og umhverfisvísindadeild (HÍ); Life and Environmental Sciences (UI); Verkfræði- og náttúruvísindasvið (HÍ); School of Engineering and Natural Sciences (UI)
Widely distributed pelagic fish populations underpin some of the largest fisheries globally and play a critical role in ecosystem dynamics by driving nutrient cycling and carbon transfer through vertical and seasonal migrations. Effective fisheries management requires understanding their spatial distribution, abundance, size structure, and the environmental factors that drive temporal variations, especially in the context of climate change. Here, we investigate the population structure of blue whiting (Micromesistius poutassou) in Icelandic waters using Bayesian hierarchical spatiotemporal models applied to bi-annual demersal survey data (1996–2023), which included 15,788 samples. Our results show that blue whiting occurrence, abundance, and size structure are influenced by physical (depth, bathymetric slope), environmental (SST, SBT), and temporal (time of day, year, season) factors. We identify three main spatial patterns: persistent aggregations along the southern shelf and Iceland-Faroes Ridge, intensifying in spring; (2) marginal transition zones to the northwest and northeast with spatiotemporal variability; and (3) fringe subpopulations in the north. These findings suggest that migration from the dominant Northeast Atlantic population primarily drives autumn distributions, while partially resident juveniles persist in local nursery areas on the southern and western shelf year-round. This study provides vital knowledge for sustainable management on blue whiting stock level responses to future climate change.
Verk
A Tool for Processing and Inversion of MASW Data and a Study of Inter-Session Variability of MASW
(ASTM International, 2024-09-01) Ólafsdóttir, Elín Ásta; Bessason, Bjarni; Erlingsson, Sigurður; Kaynia, Amir M.; Umhverfis- og byggingarverkfræðideild (HÍ); Civil and Environmental Engineering (UI); Verkfræði- og náttúruvísindasvið (HÍ); School of Engineering and Natural Sciences (UI)
Multichannel Analysis of Surface Waves (MASW) is a non-invasive active-source technique for determination of near-surface shear wave velocity (Vs) profiles. Here we introduce and describe MASWavesPy, an open-source Python package for processing and inverting MASW data, whose design follows an object-oriented paradigm. To assess the performance of the new tool, measurements were conducted at four benchmark sites in Norway, characterized as silt, soft clay, silty sand, and quick clay. The results show that the Vs profiles obtained with MASWavesPy compare well with those obtained previously at the respective sites using invasive, non-invasive and laboratory techniques. Furthermore, the efficiency and usability of the new package is superior to previous versions developed by same authors. The software can be accessed through the Python Package Index (PyPI) at https://pypi.org/project/maswavespy/, along with sample data. This work further explores the inter-session variability of MASW measurements for civil engineering applications at soft soil sites. For this purpose, repeated measurements were conducted over a seven-year period at a silty sand site in South Iceland and the recorded time series analysed using the newly developed tool. The inter-session variability of the analysis results is reported in terms of Rayleigh wave phase velocity, interval Vs profiles, and time-averaged Vs for reference depths commonly used in practise.