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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Valorization of pulp and viscera from hybrid sorubim and pacu by production of protein concentrate using alkaline solubilization
(2025-03) Azambuja, Suéllen Patrícia Held; Nascimento, Kauyse Matos; Cortez-Vega, William Renzo; Cavenaghi-Altemio, Angela Dulce; Gelinski, Jane Mary Lafayette Neves; Fonseca, Gustavo Graciano; Faculty of Natural Resource Sciences
Fish protein concentration (FPC) by alkaline solubilization has proven to be an alternative method in adding value to muscle-based materials. The aim of this work was to evaluate the influence of different processes (decanting/sieving or centrifugation), reagents (sodium bicarbonate or sodium hydroxide) and washing cycles (1–4) on the quality of protein concentrates obtained from mechanically separated meat (MSM) and viscera of hybrid sorubim (Pseudoplatystoma reticulatum × P. corruscans) and pacu (Piaractus mesopotamicus) fishes. The protein concentrate was obtained by washing the viscera or MSM during up to four cycles (4:1 solution:meat ratio). In each cycle, the liquid waste and fat were removed by decanting/sieving or centrifugation. Moisture, crude protein, crude fat and crude ash contents were determined after each washing cycle. The moisture and protein contents increased immediately after the first washing up to 77.88% (dry basis). The lipid content decreased with the cycles down to 2.99% (dry basis). Higher FPC yield was obtained for MSM during the centrifugation process compared to the decantation/sieving process. Two weight yields above 100% were found in procedures with NaHCO3 and MSM of hybrid sorubim and pacu, probably due to the larger capacity of gel formation during protein concentration. Differences related to the fish species were more evident than the processes and utilized reagents.
Development and characterization of fish nuggets obtained from mechanically separated meat of spotted sorubim
(2026-01-22) Cavenaghi-Altemio, Angela Dulce; Fonseca, Gustavo Graciano; Faculty of Natural Resource Sciences
The fish industry has recently sought to diversify its product offerings to meet high consumer demand beyond just fresh fish. The use of mechanically separated fish meat (MSM) enables the production of various products, including breaded items. This study aimed to develop fish nuggets using MSM from spotted sorubim (Pseudoplatystoma corruscans) as the primary raw material, utilizing various formulations, and to evaluate the pH, shear force, microbiological safety, and sensory attributes of the developed products . The varying ingredients (4%) were bamboo fibre (F1 ), collagen fibre (F2 ), and textured soy protein (F3 ). The average pH of 6.5 showed no statistical difference between formulations (p > 0 .05), indicating that the varying ingredients did not affect this parameter. However, shear force varied significantly (p < 0.05), with the highest value of 8 .82 N observed for F3 . Sensory analysis revealed no significant differences (p > 0.05) between formulations for most attributes, except for taste, where F1 scored higher than F2 and F3 . The acceptance index was above 80% for all formulations . F1 showed the highest “certainly would purchase” response at 26.7%. Both F1 and F3 had a combined acceptance rate of 60% for “certainly and probably would purchase”, while F2 had a 50% acceptance rate. The results suggest that taste plays a crucial role in the sensory acceptance of the nuggets, with bamboo fibre positively enhancing flavour.
Nitroxide- and trityl-based polarizing agents for MAS-DNP: Synthesis, mechanistic insights, and applications
(University of Iceland, School of Engineering and Natural Sciences, Faculty of Physical Sciences, 2026-09-14) Chatterjee, Satyaki; 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 technique for enhancing the sensitivity of nuclear magnetic resonance (NMR) spectroscopy, enabling the investigation of complex materials and biological systems that are otherwise difficult to analyze. In magic-angle spinning (MAS) under solid-state NMR, the cross-effect mechanism employs biradical polarizing agents to transfer electron polarization to surrounding nuclei. However, many polarizing agents remain difficult to synthesize, often suffer from limited aqueous solubility, and the factors governing polarization transfer are not entirely understood. This thesis describes the design, synthesis, and mechanistic investigation of nitroxide- and trityl-based polarizing agents for MAS-DNP. A high-yielding and step-efficient molecular scaffold, AsymPol-Ester, was synthesized as a versatile precursor for developing watersoluble AsymPol-derivatives of both ionic and non-ionic character, functionalized with carboxylate, phosphate, and glucosamine groups. These derivatives were obtained up to seven-fold higher overall yields than previous analogues while maintaining comparable DNP performance. Systematic structural modifications of AsymPols including linker geometry, conformational flexibility and deuteration revealed that DNP efficiency is not only influenced by electron-spin interactions but also by electron-electron coupling. For trityl-nitroxide biradicals, adding spirocycles on nitroxide reduced DNP sensitivity, that benefit bis-nitroxides, unexpectedly revealed a distinct polarization transfer mechanism in trityl-nitroxide biradicals. Further, nuclear-nuclear double resonance (NUDOR) experiments demonstrated that polarization transfer in trityl-nitroxide biradicals is strongly influenced by the large difference in electron-relaxation rates between the two radicals, in contrast to bisnitroxides where electron-electron coupling governs polarization transfer. In addition, tritylnitroxide derivative, TritylTEMPO-X, with six-fold higher aqueous solubility than PyrroTriPol, was synthesized. Finally, application-specific nitroxide radicals were developed for site-directed spin-labeling of biomolecules for local DNP enhancement, and mono-radicals for incorporation into mesoporous organosilica materials.
How different life-history strategies respond to changing environments : A multi-decadal study of groundfish communities
(2025-12) Sólmundsson, Jón; Sigurðsson, Ólafur; Jónsdóttir, Ingibjörg G.; Jónsson, Steingrímur; Faculty of Natural Resource Sciences
In recent decades, climate variability has led to significant shifts in the distribution and prevalence of various fish species in the North Atlantic. These changes are well documented for several groundfish species within the zoogeographical transition waters surrounding Iceland, coinciding with variations in seawater temperature. This study analyses groundfish assemblage structure through the frameworks of life-history theory and biogeography. Utilizing annual bottom trawl survey data from 1987 to 2024, groundfish species in the continental shelf waters around Iceland were categorized into three primary life-history strategies: periodic, opportunistic, and equilibrium, based on their life-history traits. Over the study period, these strategies demonstrated distinct responses to environmental changes, influenced by the biogeography of the species. Increased water temperatures were accompanied by an influx of Atlantic and Boreal species, while species richness for Arctic fish remained similar or decreased. Boreal periodic species emerged as the most prominent in Icelandic waters, maintaining long-term stability in abundance and distribution. However, environmental conditions in recent decades have favoured southerly warmer-water (Atlantic) species across life-history strategies, while most Arctic species have experienced declining abundance trends. Opportunistic strategists exhibited the most pronounced temporal changes during the warming period.
Cross-cultural validation of the profile of mood scale : evaluation of the psychometric properties of short screening versions
(2025) Schmalbach, Ileana; Schmalbach, Bjarne; Aghababa, Alireza; Brand, Ralf; Chang, Yu Kai; Çiftçi, Muhammet Cihat; Elsangedy, Hassan; Fernández Gavira, Jesús; Huang, Zhijian; Kristjánsdóttir, Hafrún; Mallia, Luca; Nosrat, Sanaz; Pesce, Caterina; Rafnsson, Daði; Medina Rebollo, Daniel; Timme, Sinika; Brähler, Elmar; Petrowski, Katja; Department of Sport Science; Department of Psychology
The Profile of Mood States (POMS) is one of the most widely applied scales for measuring mood. Considering the advantages of short scales and increased international research, the aim of the present study was to evaluate cross-culturally the psychometric properties of a short 16-item version of the POMS. Data were collected from 15,693 participants across 10 different countries worldwide. Initially, we identified the original versions of the POMS in various languages. Subsequently, we selected 16 items based on the previously validated short form (POMS-16) for analysis. Psychometric properties of the POMS were then evaluated in samples from each studied population for each language version. Confirmatory factor analysis was conducted to assess its invariance across age groups and gender, alongside reliability estimation. Most language versions of the POMS-16 showed a good fit with the four-factor model, except for the Chinese (traditional) and Turkish versions. Reliability was generally high, except for the Vigor subscale in a small subset of languages. Regarding measurement invariance, the majority of language versions were invariant across gender and age groups, except for the Farsi language version across gender, and the Chinese, Farsi, Finnish, and Turkish versions across age. These findings enhance the cross-cultural applicability of the POMS-16, contributing to its utility in diverse populations and thus enhancing the comparability of the results. In addition, we introduced the first versions of the POMS in Farsi, Finnish, and Icelandic.
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