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.
Nýlega bætt við
Mineralization in a Critical Size Bone-Gap in Sheep Tibia Improved by a Chitosan-Calcium Phosphate-Based Composite as Compared to Predicate Device
(2022-02-01) Örlygsson, Gissur; Laxdal, Elín H.; Kárason, Sigurbergur; Dagbjartsson, Atli; Gunnarsson, Eggert; Ng, Chuen How; Einarsson, Jón M.; Gíslason, Jóhannes; Jónsson, Halldór; Department of Engineering
Deacetylated chitin derivatives have been widely studied for tissue engineering purposes. This study aimed to compare the efficacy of an injectable product containing a 50% deacetylated chitin derivative (BoneReg-Inject™) and an existing product (chronOS Inject®) serving as a predicate device. A sheep model with a critical size drill hole in the tibial plateau was used. Holes of 8 mm diameter and 30 mm length were drilled bilaterally into the proximal area of the tibia and BoneReg-Inject™ or chronOS Inject® were injected into the right leg holes. Comparison of resorption and bone formation in vivo was made by X-ray micro-CT and histological evaluation after a live phase of 12 weeks. Long-term effects of BoneReg-Inject™ were studied using a 13-month live period. Significant differences were observed in (1) amount of new bone within implant (p < 0.001), higher in BoneReg-Inject™, (2) signs of cartilage tissue (p = 0.003), more pronounced in BoneReg-Inject™, and (3) signs of fibrous tissue (p < 0.001), less pronounced in BoneReg-Inject™. Mineral content at 13 months postoperative was significantly higher than at 12 weeks (p < 0.001 and p < 0.05, for implant core and rim, respectively). The data demonstrate the potential of deacetylated chitin derivatives to stimulate bone formation.
Bone remodeling effect of a chitosan and calcium phosphate-based composite
(2019-08-01) Kjalarsdóttir, Lilja; Dýrfjörd, Arna; Dagbjartsson, Atli; Laxdal, Elín H.; Örlygsson, Gissur; Gíslason, Jóhannes; Einarsson, Jón M.; Ng, Chuen How; Jónsson, Halldór; Department of Engineering
Chitosan is a biocompatible polymer that has been widely studied for tissue engineering purposes. The aim of this research was to assess bone regenerative properties of an injectable chitosan and calcium phosphate-based composite and identify optimal degree of deacetylation (%DDA) of the chitosan polymer. Drill holes were generated on the left side of a mandible in Sprague-Dawley rats, and the hole was either left empty or filled with the implant. The animals were sacrificed at several time points after surgery (7-22 days) and bone was investigated using micro-CT and histology. No significant new bone formation was observed in the implants themselves at any time points. However, substantial new bone formation was observed in the rat mandible further away from the drill hole. Morphological changes indicating bone formation were found in specimens explanted on Day 7 in animals that received implant. Similar bone formation pattern was seen in control animals with an empty drill hole at later time points but not to the same extent. A second experiment was performed to examine if the %DDA of the chitosan polymer influenced the bone remodeling response. The results suggest that chitosan polymers with %DDA between 50 and 70% enhance the natural bone remodeling mechanism.
Epidemiology of spinal fractures and associated spinal cord injuries in Iceland
(2018-12) Kristinsdóttir, Eyrún Arna; Knútsdóttir, Sigrún; Sigvaldason, Kristinn; Jónsson, Halldór; Ingvarsson, Páll E.; Department of Engineering
Study design: A retrospective epidemiological study. Setting: Landspítali University Hospital, Iceland. Objectives: Assessment of epidemiological data and risk factors for traumatic spinal fractures (SFs) and associated spinal cord injury (SCI). Methods: A retrospective review of hospital admissions due to traumatic SFs during a 5-year period, with analysis of epidemiological parameters and occurrence of concomitant SCI. Patients with asymptomatic SFs and non-traumatic SCI were excluded. Results: A total of 487 patients were diagnosed with a SF or 310 PMI (per million inhabitants), 42 of them (9%, 27 PMI) with an associated SCI. The mean age was 56 years, males were 57%. Falls were the leading cause of both SFs (49%) and SCIs (43%). Low falls (<1 m) caused SFs more often in elderly women (67%, mean age 77 years) and more than 96% were without SCI. Road traffic accidents (RTA) caused 31% of SFs and 26% of SCIs. Seat belts were not used in 20% of car accidents, but information was missing in 27%. Sports/leisure-related accidents caused SFs in 12% of cases, whereof horseback riding accidents were the most common (36%). Conclusions: SFs led to SCI in 9% of patients. Several risk factors were common for SFs and SCIs but two major differences were seen: SFs without SCI were most common in older women due to low falls, while the risk of a concomitant SCI increased in young patients, in males, in falls from high levels and when driving without using seat belts. Preventive efforts should therefore be directed towards these risk factors.
Activation of Complement Following Total Hip Replacement
(2016-03-01) Thordardottir, S.; Vikingsdottir, T.; Bjarnadottir, H.; Jonsson, H.; Gudbjornsson, B.; Department of Engineering
The aim of this study was to investigate whether complement activation, via the classical and alternative pathways, occurs following a cemented total hip replacement (THR) surgery due to osteoarthritis. Blood samples were collected systematically from 12 patients - six male and six women, with a median age of 75 (range: 59-90 years) - preoperatively, 6 h post-operatively and on the first, second and third post-operative day. Total function of classical (CH50) and alternative pathways (AH50) was evaluated, along with the determination of serum concentrations of the complement proteins C3, C4, C3d, the soluble terminal complement complex (sTCC) sC5b-9, as well as C-reactive protein (CRP) and albumin. Measurements of CRP and albumin levels elucidated a marked inflammatory response following the operation. The CH50, AH50 and C3 and C4 levels were significantly lower 6 h after the surgery compared with the preoperative levels, but elevated above the preoperative levels during the following 3 days. The complement activation product C3d levels increased continually during the whole observation period, from 13.5 AU/ml (range: 8-19 AU/ml) preoperative to 20 AU/ml (range: 12-34 AU/ml) on the third post-operative day. Furthermore, we observed an increase in the sC5b-9 levels between the preoperative and the third post-operative day. These results demonstrate a significant activation of the complement system following cemented THR. Further studies are needed to elucidate the time frame and the pathogenic role of this observed complement activation.
The Scandinavian Sarcoma Group Central Register : 6,000 patients after 25 years of monitoring of referral and treatment of extremity and trunk wall soft-tissue sarcoma
(2017-05-04) Trovik, Clement; Bauer, Henrik C.F.; Styring, Emelie; Sundby Hall, Kirsten; Vult Von Steyern, Fredrik; Eriksson, Sigvard; Johansson, Ingela; Sampo, Mika; Laitinen, Minna; Kalén, Anders; Jónsson, Halldór; Jebsen, Nina; Eriksson, Mikael; Tukiainen, Erkki; Wall, Najme; Zaikova, Olga; Sigurðsson, Helgi; Lehtinen, Tuula; Bjerkehagen, Bodil; Skorpil, Mikael; Egil Eide, Geir; Johansson, Elisabeth; Alvegard, Thor A.; Department of Engineering
Purpose — We wanted to examine the potential of the Scandinavian Sarcoma Group (SSG) Central Register, and evaluate referral and treatment practice for soft-tissue sarcomas in the extremities and trunk wall (STS) in the Nordic countries. Background — Based on incidence rates from the literature, 8,150 (7,000–9,300) cases of STS of the extremity and trunk wall should have been diagnosed in Norway, Finland, Iceland, and Sweden from 1987 through 2011. The SSG Register has 6,027 cases registered from this period, with 5,837 having complete registration of key variables. 10 centers have been reporting to the Register. The 5 centers that consistently report treat approximately 90% of the cases in their respective regions. The remaining centers have reported all the patients who were treated during certain time periods, but not for the entire 25-year period. Results — 59% of patients were referred to a sarcoma center untouched, i.e. before any attempt at open biopsy. There was an improvement from 52% during the first 5 years to 70% during the last 5 years. 50% had wide or better margins at surgery. Wide margins are now achieved less often than 20 years ago, in parallel with an increase in the use of radiotherapy. For the centers that consistently report, 97% of surviving patients are followed for more than 4 years. Metastasis-free survival (MFS) increased from 67% to 73% during the 25-year period. Interpretation — The Register is considered to be representative of extremity and trunk wall sarcoma disease in the population of Scandinavia, treated at the reporting centers. There were no clinically significant differences in treatment results at these centers.
Flokkar í Opnum vísindum
Veldu flokk til að skoða.
- University of Iceland
- University of Akureyri
- Bifröst University
- Hólar University College
- IRIS
- Agricultural University of Iceland
- National and University Library of Iceland
- Iceland University of the Arts