| 1. |
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| 2. |
- Trilla, Lluis, 1981, et al.
(författare)
-
Wave farm collection grid analysis and design
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In this report, the collection grid of a wave farm is designed and analysed, the system under consideration goes from the connection point at each power converter (included in each wave energy unit) up to the point of common connection with the main grid. Time series that have been provided by Ocean Harvesting Technologies (OHT), being obtained from their simulation models for a scaled prototype and include data for mild, medium and strong sea states. The simulation models have been validated against small scale tank testing of a prime mover, a wave rider buoy, and scaled testing of the power take-off in a land based test-rig. Wave data is taken from EMEC, Scotland [7]. The design of the collection grid aims to optimize its size by minimizing its cost while maximizing the power output. For the economical assessment three layouts are taken into account and several scenarios for different energy prices and interest rates are presented. A life-cycle analysis is also done where the entire life span of the collection grid is considered showing that around 30Euro/MWh will be the share of the electricity price required to install and operate the collection grid. The power quality of the resultant layout and its compliance with the grid code of the UK are analysed as well. This analysis includes power factor and voltage fluctuation estimation, line-fault ride-through assessment and flicker contribution analysis. Given the pulsating nature of the wave power systems special emphasis in the study of flicker emissions is done concluding that the proposed wave park is within the grid code limitations and even a reduction of a 66% in the flicker coefficients is reported when considering the aggregation of several units in one model.
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| 3. |
- Aagergaard, Sine, et al.
(författare)
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Scandinavian women’s football in world : migration, management and mixed identity
- 2013
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Ingår i: Soccer & Society. - : Taylor & Francis. - 1466-0970 .- 1743-9590. ; 14:6, s. 769-780
-
Tidskriftsartikel (refereegranskat)abstract
- This special issue has grown out of an ongoing Nordic collaborative research project (Nordcorp) using Scandinavian women’s football as a strategically selected extreme case (of organizational development) to study a Nordic sport model in transition. The common point of interest for the project group, which overlaps with the editors and authors in this issue of Soccer and Society, is a fascination with the current development of Scandinavian women’s football that stands out as an intriguing subject for bothsports research and the social sciences.
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| 4. |
- Abel, I, et al.
(författare)
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Overview of the JET results with the ITER-like wall
- 2013
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 53:10, s. 104002-
-
Tidskriftsartikel (refereegranskat)abstract
- Following the completion in May 2011 of the shutdown for the installation of the beryllium wall and the tungsten divertor, the first set of JET campaigns have addressed the investigation of the retention properties and the development of operational scenarios with the new plasma-facing materials. The large reduction in the carbon content (more than a factor ten) led to a much lower Z(eff) (1.2-1.4) during L- and H-mode plasmas, and radiation during the burn-through phase of the plasma initiation with the consequence that breakdown failures are almost absent. Gas balance experiments have shown that the fuel retention rate with the new wall is substantially reduced with respect to the C wall. The re-establishment of the baseline H-mode and hybrid scenarios compatible with the new wall has required an optimization of the control of metallic impurity sources and heat loads. Stable type-I ELMy H-mode regimes with H-98,H-y2 close to 1 and beta(N) similar to 1.6 have been achieved using gas injection. ELM frequency is a key factor for the control of the metallic impurity accumulation. Pedestal temperatures tend to be lower with the new wall, leading to reduced confinement, but nitrogen seeding restores high pedestal temperatures and confinement. Compared with the carbon wall, major disruptions with the new wall show a lower radiated power and a slower current quench. The higher heat loads on Be wall plasma-facing components due to lower radiation made the routine use of massive gas injection for disruption mitigation essential.
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| 5. |
- Almgren, Maria, et al.
(författare)
-
Länge leve skolan! En text om utbildning, estetik och skolutveckling
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Denna skrift har arbetats fram av en grupp studenter på Lärande och samhälle som fortsättning och utveckling av examinationsuppgift på en terminslång kurs, där de hade att iscensätta ett dokumentärfilmsprojekt på högstadiet. Projektet ägde rum inom ramen för huvudämnet Kultur, medier, estetik (KME) - skapat genom en sammanslagning av estetiska ämnen med medie- och kulturstudier 2001 – som ända från starten har tillskrivit det estetiska en särskild förmåga att vända upp och ner på invanda synsätt och kritiserat skolan för att inte lämna tillräckligt utrymme åt denna radikala potential. Den som är det minsta intresserad av skol- och kulturarbete kan inte undgå att dras in i det nät av glödande engagemang, intrikata spörsmål och brottstycken av teoretiska diskussioner som dessa sju studenter väver. Man kommer mycket nära de problem de brottas med utan att någonsin hitta några definitiva svar. Viljan att göra nytt tillsammans med eleverna och med utgångspunkt i deras horisont är obändig. Men så är det ramarna för arbetet... De sju befinner sig i ett interregnum, i en korseld av krav från lärarutbildarna, lärarna på skolan och eleverna, som påminner dem: "Ni är inte våra lärare. Ni kommer hit några timmar i veckan från någon annanstans". Ingenting visar sig vara enkelt. Varför gläds inte eleverna åt att få göra något som kan få betydelse för dem "på riktigt"? Vad är egentligen skillnaden mellan dokumentär- och fiktionsfilm? Hur bedömer man elevernas prestationer i ett så pass öppet projekt? Finns det över huvud taget rum i dagens skola för en pedagogik som vill vara på en gång passionerad, polyfon, prövande och provokativ? Alla dessa är ord som väl kännetecknar skriftens första del, ett grafiskt kaos av utlagda spår som läsaren kan välja bland att följa. Här får man en "cut-up-bild" av de tankevärldar som studenterna försöker orientera sig mot och inom. Den läsare som finner estetiken för provocerande kan alltid börja med andra delen i stället, som analytiskt redogör för de olika filmprojekten. Del tre, slutligen, diskuterar förutsättningarna för de förhållningssätt som utvecklats inom KME att göra sig gällande inom ramen för den nya läroplanen Lgr 11.
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| 6. |
- Andersson, A., et al.
(författare)
-
An analysis of inverter switching loss minimization based on discontinuous PWM for a salient-pole PMSM
- 2014
-
Ingår i: 2014 16th European Conference on Power Electronics and Applications (EPE'14-ECCE Europe), Lappeenranta, Finland, 26-28 August 2014. - 2325-0313. - 9781479930159
-
Konferensbidrag (refereegranskat)abstract
- This article presents the result of an inverter switching loss minimization technique based on discontinuous PWM patterns for a salient-pole PMSM with a two-level voltage source inverter for an automotive application. The suggested PWM patterns are evaluated using the resulting electromagnetic torque considering peak-to-peak ripple as well as the DC-current harmonic spectra. The study focuses on high rotational speeds, from 0.6-2.5 ωbase considering both current and voltage limitations. The analysis focuses on electromagnetic torque characteristics evaluated at steady state operation. The results show that the electromagnetic torque ripple is increased by up to 73 % and 78 % whereas the inverter switching losses is decreased by up to -17%and -41%for the EUDC driving cycle using DPWM30 and DPWM60, respectively.
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| 7. |
- Andersson, A., et al.
(författare)
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Inverter losses minimization using variable switching frequency based on multi-objective optimization
- 2014
-
Ingår i: Proceedings - 2014 International Conference on Electrical Machines, ICEM 2014. - 9781479943890 ; :Art. no. 6960271, s. 789-795
-
Konferensbidrag (refereegranskat)abstract
- This article presents the result of an VSI-losses minimization technique based on multi-objective convex optimization for a salient-pole PMSM with a two-level VSI for an automotive application. The optimization, using the switching frequency as control variable, is based on a multi-objective cost function defined by the combination of VSI-losses and electromagnetic torque peak-peak ripple, analytically expressed using time-domain current predictions. The optimization target is to keep an optimum balance between VSI-losses and electromagnetic torque ripple, using variable switching frequency (VSF). The primary objective with this article is the presented design methodology. Simulations are used to verify functionality as well as influence of different scaling factors. In addition, the NEDC driving cycle is used to further quantify the results for two different cost function setups.
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| 8. |
- Andersson, Jonas, 1977-, et al.
(författare)
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Effects of heavy endurance physical exercise on inflammatory markers in non-athletes
- 2010
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Ingår i: Atherosclerosis. - : Elsevier BV. - 0021-9150 .- 1879-1484. ; 209:2, s. 601-605
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Physical activity has beneficial effects on cardiovascular disease but the mechanisms are still somewhat unclear. One possible pathway may be through the anti-inflammatory effects attributed to regular physical activity. Our primary aim was to study the effects of endurance physical exercise on C-reactive protein (CRP), Interleukin-6 (IL-6), Tumor Necrosis Factor-alpha (TNFalpha) during the acute and recovery phases. Secondarily, we studied the impact of diet on these inflammatory markers.METHODS: Twenty men, aged 18-55 years, participated in a 14 days cross-country skiing tour. They traveled 12-30km per day corresponding to about 10h of heavy physical activity. The participants were randomized to a diet with either 30 or 40% of energy derived from fat. Inflammatory variables were analysed at week 0, after 1 and 2 weeks and during the recovery phase at week 6 and 8.RESULTS: CRP and TNFalpha increased significantly during the two weeks of exercise (1.4-5.0mg/l, p=0.00 and 6.8-8.4pg/ml, p=0.00). CRP levels were significantly lower during recovery (median 0.7mg/l) compared to baseline (median 1.4mg/l) and did not correlate to metabolic variables. There were no significant changes in IL-6 levels during the study period. For dietary groups significant CRP changes were observed only in the high fat group during recovery.CONCLUSIONS: CRP and TNFalpha increased significantly but reacted differently during heavy physical activity while there seemed to be no significant changes in IL-6. No significant differences regarding inflammatory variables were found between the dietary groups.
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| 9. |
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| 10. |
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| 11. |
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| 12. |
- Andersson, Torbjörn, et al.
(författare)
-
A diagnosis of the commercial immaturity of Swedish club football
- 2011
-
Ingår i: Soccer & Society. - : Taylor & Francis. - 1466-0970 .- 1743-9590. ; 12:6, s. 754-773
-
Tidskriftsartikel (refereegranskat)abstract
- This article presents a critical diagnosis of Swedish club football, in light of its current shortcomings on the European football market, and in comparison with the other Scandinavian leagues. The article highlights the commercial immaturity of the Swedish clubs, in addition to the context of historical and cultural values, restricted association forms, the emphasis on internationalism, the fixed tax system, the standards of the arenas, the lack of patronage and the migration of talents. The analysis closes with a depressed depiction of Swedish club football, in relation to development in Europe, as well as in Scandinavia. Still, in a dialectical reasoning this situation is, finally, evaluated as a valuable development in relation to fairness, internal sports logics as well as ecological values.
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| 13. |
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| 14. |
- Andersson, Torbjörn
(författare)
-
Den svenska fotbollens glokaliseringsprocess
- 2012
-
Ingår i: Kampen om tribunen. - : Akademika forlag. - 9788251929325 - 8251929326 ; , s. 69-88
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 15. |
- Andersson, Torbjörn, 1976-, et al.
(författare)
-
Desirability in the development of In-Car Infotainment Systems
- 2011
-
Ingår i: Workshop: User Experience in Cars.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper describes a workflow for designing experiences whileinteracting with an advanced driver assistant system. Future driver assistancesystems that utilize sensors and Car2X-communication in order to detect threatsin the car environment can help the driver to avoid collisions. To increase theacceptance of such a system, the interaction between the driver and the systemshould be able to generate positive experiences. To generate those experiences,a story-based design workflow was used. Concepts created with this workflowshould be able to address specific psychological needs of the driver. Theimplementation of this workflow revealed different schemes of positiveexperiences during driver interaction in critical situations.
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| 16. |
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| 17. |
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| 18. |
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| 19. |
- Andersson, Torbjörn, 1976-, et al.
(författare)
-
Product gist : An approach to identifying form characteristics of the current product sign
- 2013
-
Konferensbidrag (refereegranskat)abstract
- In today's competitive market it is essential for companies to have a clear brand identity towards it consumers and users in order to be successful. Consumers have often a variety of products to choose from and the challenge for a company's products is to be discovered and remembered. An important factor is recognition of a product and how it is conceived through our perception which is mainly an identification process based on familiarity, resemblance or similarity. Furthermore, the visual part of the brain organizes the surrounding into patterns which are used as a guide for us, and to capture the surrounding is called getting its gist. The process of finding resemblance in a design space is often done by the designer as an implicit part in the design process. If this implicit knowledge could be more objectively visualised it might be a helpful tool to create a visual baseline of how consumers would experience the product segment. To show similarities and differences of design features quantitatively can facilitate the communication in a design development project. This paper explores how the concept of a product gist may be used to create a conceptual product sign and also how it could be used to analyse what the design space looks like in a given product segment. By quantitatively overlaying transparent pictures in a product segment visual pattern emerges that can be used as a communication tool in a design process when discussing brand recognition. In this paper a power drill is used as a simple application to illustrate the usage of the proposed product gist.
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| 20. |
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| 21. |
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| 22. |
- Andersson, Torbjörn
(författare)
-
Svensk fotbollshuliganism 1900-1970
- 2010
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Ingår i: Fotboll och huliganism i Skandinavien. - : Idrottsforum.org. - 9789185645107 ; , s. 11-33
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 23. |
- Andersson, Torbjörn, et al.
(författare)
-
Sweden
- 2013
-
Ingår i: Standing up for your right(s) in Europe. - Cambridge : Intersentia. - 1780681569 - 9781780681566 ; , s. 517-569
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 24. |
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| 25. |
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| 26. |
- Backman, Jyri, 1968-
(författare)
-
I skuggan av NHL : en organisationsstudie av svensk och finsk elitishockey
- 2012
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- I denna licentiatuppsats har svenska elitseriens respektive finska SM-liigas seriemodeller analyserats i ljuset av NHL:s dominans över den globala ishockeyn. Bakgrunden till problemområdet är att företrädarna för svensk respektive finsk elitishockey implementerat olikartade organisatoriska lösningar, trots att de utvecklats i kontexter med likartade sportmodeller och samhällsvillkor. Metodologiskt bygger denna licentiatuppsats på komparativa studier. Som grund för min analys har jag använt mig av dokumentanalys med inslag av rättsdogmatik. Den teoretiska ramen har utgjorts av historikern Martin Alms amerikaniseringsbegrepp samt juristen och forskaren Lars Halgreens analys om amerikaniseringen av europeisk sport. Följande frågeställningar har analyserats: Hur har elitserien respektive SM-liiga utvecklats i relation till den amerikanska respektive europeiska sportmodellen, sedan 1970-talets mitt? Vilka kännetecken kan fastställas för de respektive organisationsmodellerna? På vilka sätt skiljer respektive liknar de varandra samt vilka förutsättningar för parallellverkan kan urskiljas, dels generellt och dels specifikt i en ishockeykontext? Vilka tendenser och inslag kan skönjas i elitserien respektive SM-liiga av det faktum att ishockeyn genom åren både sportsligt och kommersiellt dominerats av NHL? Min studie visar att ishockeysporten är en spjutspets i amerikaniseringen och kommersialiseringen av nordisk sport samt att ishockeyns kommersialisering och professionalisering i någon form leder till en amerikanisering. Studien visar att företrädarna för den finska elitishockeyn haft stor autonomi präglat av förbundssplitting, vilket har sin förklaring i Finlands 1900-talshistoria. Denna självständighet har utgjort grund för den finska elitishockeyns snabba och häftiga utveckling efter andra världskriget. I jämförelse är Sverige präglat av konsensusorientering med Sveriges Riksidrottsförbund som centraladministration och paraplyorganisation för hela den svenska idrotten, även om Svenska Hockeyligan Ab på senare år fått allt större roll inom svensk ishockey. En slutsats är att Finlands högsta ishockeyserie kan anses vara en hybrid mellan den amerikanska respektive europeiska sportmodellen. Sveriges högsta ishockeyserie är å andra sidan närmare sammanlänkad med den europeiska sportmodellen, även om det finns stora kommersiella intressen inom svensk elitishockey.
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| 27. |
- Berglund, Martina, et al.
(författare)
-
Theme-based assessment of education in design and product development
- 2014
-
Ingår i: Proceedings of the 10th International CDIO Conference. - : Universitat Politècnica de Catalunya.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- One fundamental challenge in choosing an examination form to assess student achievements is to find an examination which, both encourages students to continuously elaborate the course content and constitutes a learning process itself. The objective of this paper is to share and reflect on the development and implementation of a new theme-based examination in a six credit course in Product Ergonomics given in the engineering programme Design and Product Development at Linköping University, Sweden. The course runs during four months and has two parts: one theoretical and one applied. The former focuses on theoretical ergonomic topics, models and methods while the latter is a project aiming at consolidating the students’ understanding of the theory by implementing the knowledge in a product development case. To encourage the students to adapt a deep learning approach, the traditional written mid-term exam for the theoretical part was abandoned and another concept developed. In the new concept, the theoretical part was split onto six weekly themes. Each theme was introduced at the beginning of the week by high-lighting main theories and models followed by a group-work assignment to be elaborated on by the students during the week. The theme was examined at the end of the week through a short written exam and a seminar to discuss and reflect upon the theme. From a student perspective, the positive outcome of the theme-based examination was peer learning and a more active learning style. The students appreciated the theme-based structure of the course. Occasionally, some students commented that weekly examinations could be perceived as stressful. The teachers perceived the students to be more acquainted with ergonomics theory and methods which increased the quality of the course project. The reported theme-based assessment is one example of implementing among others the CDIO syllabus parts 2.2 and 3.1and CDIO standards 8 and 11.
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| 28. |
- Björkman, Torbjörn, 1977-, et al.
(författare)
-
Theoretical studies of the incommensurate magnetic structure of a heavy fermion system: CeRhIn5
- 2010
-
Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 81:9, s. 094433-
-
Tidskriftsartikel (refereegranskat)abstract
- We have investigated the electronic structure and the incommensurate magnetic configuration of the pressure-induced superconductor CeRhIn5. Noncollinear first-principles calculations were performed in the local-density approximation plus U scheme. The observed magnetic configuration is described accurately in our calculations, especially considering the minute energy scale which is relevant (microelectron volt). The band structure and Fermi surfaces were investigated and nesting was found to be responsible for the complex noncollinear magnetic state of CeRhIn5.
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| 29. |
- Boman, Mats, et al.
(författare)
-
Corrosion of copper in water free from molecular oxygen
- 2014
-
Ingår i: Corrosion Engineering, Science and Technology. - 1478-422X .- 1743-2782. ; 49:6, s. 431-434
-
Tidskriftsartikel (refereegranskat)abstract
- The possibility of copper reacting with O-2-free water has been investigated by analysis of primary corrosion products, as well as by monitoring gas pressure change by time, in long term experiments for up to 6 months in a glove box environment. We establish hydrogen production, but being of the same magnitude irrespective whether copper is present or not. Although low, the hydrogen production rate is considerably larger than what would directly correspond to the amount of analysed copper oxidation products. Our analyses encompass the changes to the surface cleaned copper (99.9999%), the water phase and the Duran glass in contact with the water (ppt quality). We have used very sensitive methods (XPS, AES, ICP-MS, XRF) while keeping contamination risks to a minimum. We conclude that the oxidation rate of copper is very low, yielding only parts of a monolayer of Cu2O after 6 months of exposure at 50 degrees C together with an accompanying very low concentration of copper species (4-5 mu g L-1) in the water phase.
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| 30. |
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| 31. |
- Du, Juan, et al.
(författare)
-
Prevalence of Oral Human Papillomavirus Infection among Youth, Sweden
- 2012
-
Ingår i: Emerging Infectious Diseases. - : Centers for Disease Control and Prevention. - 1080-6040 .- 1080-6059. ; 18:9, s. 1468-1471
-
Tidskriftsartikel (refereegranskat)abstract
- Human papillomavirus (HPV) causes cervical, head, and neck cancers. We studied 483 patients at a youth clinic in Stockholm, Sweden, and found oral HPV prevalence was 9.3% and significantly higher for female youth with than without cervical HPV infection (p = 0.043). Most oral HPV types matched the co-occurring cervical types.
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| 32. |
- Elgmark Andersson, Elisabeth, 1958-, et al.
(författare)
-
MILD TRAUMATIC BRAIN INJURIES: A 10-YEAR FOLLOW-UP
- 2011
-
Ingår i: JOURNAL OF REHABILITATION MEDICINE. - : Foundation for Rehabilitation Information. - 1650-1977 .- 1651-2081. ; 43:4, s. 323-329
-
Tidskriftsartikel (refereegranskat)abstract
- Objective and design: Long-term consequences of mild traumatic brain injuries were investigated based on a 10-year follow-up of patients from a previously-published randomized controlled study of mild traumatic brain injuries. One aim was to describe changes over time after mild traumatic brain injuries in terms of the extent of persisting post-concussion symptoms, life satisfaction, perceived health, activities of daily living, changes in life roles and sick leave. Another aim was to identify differences between the intervention and control groups. Patients: The intervention group comprised 142 persons and the control group 56 persons. Methods: Postal questionnaires with a response rate of 56%. Results: No differences over time were found for the intervention and control groups in terms of post-concussion symptoms. In the intervention group some variables in life satisfaction, perceived health and daily life were decreased. Some roles had changed over the years for both groups. No other differences between the intervention and control groups were found. However, in both groups sick leave decreased. Conclusion: Early individual intervention by a qualified rehabilitation team does not appear to impact on the long-term outcome for persons with symptoms related to mild traumatic brain injuries. The status after approximately 3 weeks is indicative of the status after 10 years.
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| 33. |
- Eriksson, Lars, et al.
(författare)
-
Driver acceptance and performance with LDW and rumble strips assistance in unintentional lane departures
- 2013
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In this ViP project the focus of investigation was whether drivers more readily accept either rumble strips or an in-vehicle lane departure warning system (LDW) in unintentional lane departure situations. The results show that acceptance was high for both alternatives, but while the drivers showed more satisfaction from using the LDW, they also showed more trust in the rumble strips. Twenty-four drivers drove the VTI driving simulator SIM III in car mode with simulated rumble strips in one drive and with a simulated Volvo LDW in another drive. A forced yaw motion of the vehicle induced the unintentional lane departures. The results showed no choice in favour of the LDW or the rumble strips, but a clear preference for having a function that warns for unintentional lane departure. Several participants thought it was good to have both types of warning in parallel. Although Response completion time was shorter with the rumble strips warning, there was no difference between the warning types, neither in Time to get car back in lane nor in Lane exceedence area. Thus, there were no major overall differences between the LDW and the rumble strips as measured in the present study. The conclusion is that the drivers’ acceptance, as well as performance, was high for both the rumble strips and the LDW. The positive opinion on the need for assistance systems in unintentional lane departure when drivers are directing their visual attention away from the road is thus further strengthened.
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| 34. |
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| 35. |
- Fujita, S., et al.
(författare)
-
Spatial and temporal variability of snow accumulation rate on the East Antarctic ice divide between Dome Fuji and EPICA DML
- 2011
-
Ingår i: The Cryosphere. - : Copernicus GmbH. - 1994-0416 .- 1994-0424. ; 5:4, s. 1057-1081
-
Tidskriftsartikel (refereegranskat)abstract
- To better understand the spatio-temporal variability of the glaciological environment in Dronning Maud Land (DML), East Antarctica, a 2800-km-long Japanese-Swedish traverse was carried out. The route includes ice divides between two ice-coring sites at Dome Fuji and EPICA DML. We determined the surface mass balance (SMB) averaged over various time scales in the late Holocene based on studies of snow pits and firn cores, in addition to radar data. We find that the large-scale distribution of the SMB depends on the surface elevation and continentality, and that the SMB differs between the windward and leeward sides of ice divides for strong-wind events. We suggest that the SMB is highly influenced by interactions between the large-scale surface topography of ice divides and the wind field of strong-wind events that are often associated with high-precipitation events. Local variations in the SMB are governed by the local surface topography, which is influenced by the bedrock topography. In the eastern part of DML, the accumulation rate in the second half of the 20th century is found to be higher by similar to 15% than averages over longer periods of 722 a or 7.9 ka before AD 2008. A similar increasing trend has been reported for many inland plateau sites in Antarctica with the exception of several sites on the leeward side of the ice divides.
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| 36. |
- Halawa, Imad, et al.
(författare)
-
Hyponatremia and risk of seizures : A retrospective cross-sectional study
- 2011
-
Ingår i: Epilepsia. - : Wiley. - 0013-9580 .- 1528-1167. ; 52:2, s. 410-413
-
Tidskriftsartikel (refereegranskat)abstract
- This retrospective cross-sectional study was carried out to study the association between different levels of hyponatremia and the occurrence of epileptic seizures in patients without a prior epilepsy diagnosis. We identified from the hospital database, 363 inpatients of a Swedish County hospital who between March 2003 and August 2006 were found to have serum sodium levels < 125 mm. Medical records were reviewed and we identified 11 patients with seizures in conjunction with their hyponatremia. Seizures were the only neurologic manifestation of hyponatremia in patients with serum sodium levels > 115 mm. Of 150 patients reviewed with serum sodium levels of 120-124 mm, one had a seizure. Using 120-124 mm as reference, odds ratios (95% confidence interval) for having seizures at serum sodium levels of 115-119 mm was 3.85 (0.40-37.53), 8.43 (0.859-82.85) at 110-114 mm, and 18.06 (1.96-166.86) at < 110 mm.
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| 37. |
- Helenius, Malin, 1978-
(författare)
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Investigation of Bladder Tumors with CT Urography in Patients Presenting with Gross Hematuria
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Bladder tumor is the most common tumor detected in patients presenting with gross hematuria. Early detection and treatment is crucial for good prognosis, however, delay in diagnosis and treatment is common. Routine work-up of gross hematuria includes cystoscopy and Computed Tomography Urography (CTU). If CTU has a high detection rate of bladder tumor, it can be used to direct further investigation of the patient, hopefully reducing delay to diagnosis and treatment. There is no consensus on which phase the bladder should be assessed at CTU. Assessment of the bladder in an early contrast-enhancing phase requires contrast material enhancement in bladder tumors and a bladder that is properly distended with urine. For patients younger than 50 years, the routine CTU protocol used for examining gross hematuria patients included unenhanced (UE), corticomedullary phase (CMP), and excretory phase (EP), with the start of the scan being enhancement triggered: patients aged 50 years or older followed the same protocol plus a nephrographic phase (NP).The CTU protocol was compared with flexible cystoscopy for detecting bladder tumors. Sensitivity for bladder cancer detection was equal for CTU and cystoscopy (0.87).Patients diagnosed with bladder cancer (n=50) were examined during UE, CMP, and EP, and 21 patients were additionally examined in NP. The highest mean tumor contrast enhancement was seen in CMP (37 HU).The CMP, NP, and EP in 106 patients were randomized into an evaluation order (n=318 different phases) and blindly reviewed by two uroradiologists. In CMP, sensitivity (0.95) and negative predictive value (0.99) were higher than in NP and EP.Four different preparation protocols for achieving bladder distension were compared. The protocol that included drinking 1 l of fluid during a two-hour period prior to examination without voiding during that period, gave satisfactory bladder distension without causing unacceptable patient discomfort and having the lowest compliance. Gross hematuria patients should be primarily examined with CTU including UE, CMP and EP to direct further investigation of the patients. The patients should follow a preparation protocol including drinking 1 l of fluid during a two-hour period before examination and not voiding during that period.
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| 38. |
- Hudl, Matthias, et al.
(författare)
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Order–disorder induced magnetic structures of FeMnP0.75Si0.25
- 2011
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 83:13, s. 134420-
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Tidskriftsartikel (refereegranskat)abstract
- We report on the synthesis and structural characterization of the magnetocaloric FeMnP0.75Si0.25 compound. Two types of samples (as quenched and annealed) were synthesized and characterized structurally and magnetically. We have found that minute changes in the degree of crystallographic order causes a large change in the magnetic properties. The annealed sample, with higher degree of order is antiferromagnetic with a zero net moment. The as-quenched sample has a net moment of 1.26 μB /f.u. and ferrimagnetic-like behavior. Theoretical calculations give rather large values for the Fe and Mn magnetic moments, both when occupied on the tetrahedral and pyramidal lattice site. The largest being the Mn moment for the pyramidal site reaches values as high as 2.8 μB /atom.
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| 39. |
- Innala, Eva, 1956-
(författare)
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Acute intermittent porphyria, women and sex hormones. Screening for hepatocellular carcinoma in porphyria
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Porphyrias are inherited disorders with impaired heme biosynthesis. Acute intermittent porphyria (AIP) is the most common porphyria in Sweden. AIP attacks may be life-threatening. Female sex hormones are regarded as important precipitating factors. Hepatocellular carcinoma (HCC) is a severe complication in the older AIP population. The aim of the thesis was to describe the clinical expression of AIP in women, experience of hormonal contraception and hormonal replacement therapies (HRT) and of pregnancies. Secondly, we evaluated gonadotropin-releasing hormone (GnRH) agonist treatment for prevention of menstrual-cycle-related AIP attacks. Thirdly, we evaluated whether an altered sex-steroid metabolism was present in AIP women compared with controls. Finally, we evaluated the benefit of screening for HCC in AIP in a 15-year follow-up study. Methods and results: In a retrospective population-based study in northern Sweden, 166 female AIP gene carriers ≥18 years of age participated. Manifest AIP (MAIP) was reported in 55%; 82% had severe attacks and 39% had menstrual-cycle-related attacks. Hormonal contraceptives were used by 94, and 12 reported that this precipitated AIP attacks. HRT and local vaginal treatments in menopause did not precipitate AIP attacks. Only 10% reported impairment of AIP symptoms during pregnancy. In the retrospective follow-up study of GnRH-agonist treatment, 11 of 14 women improved during treatment. Porphyria attacks were triggered in two women after estradiol add-back and in 5 of 9 women after progesterone add-back. In the sex-steroid metabolism study, levels of s-progesterone, estradiol, allopregnanolone and pregnanolone during the menstrual cycle in 32 AIP gene carriers were compared with 20 healthy controls. Progesterone metabolism in the AIP group differed from controls. In the AIP group levels of allopregnanolone, but not pregnanolone, were significantly lower. In the prospective HCC screening study AIP gene carriers aged >55 years were included. On average 62 subjects participated during 15 years. HCC was diagnosed in 22 of 180 eligible AIP gene carriers in the region (male:female, 12:10, 73% MAIP). The annual incidence of HCC was 0.8%. The risk of HCC was 64-fold higher than in the general population over 50 years of age in this region, and even higher for AIP women (93-fold). Increased 3- and 5-year survival was seen in the regularly screened AIP group. Liver lab tests were not useful in HCC screening. Conclusion: The clinical expression of AIP in women is pronounced and menstrual-cycle-related attacks are common. Hormonal contraceptives can induce AIP attacks and caution is recommended. GnRH-agonist treatment can ameliorate menstrual-cycle-related attacks of porphyria. Dose findings for GnRH-agonists and add-back regimes, especially for progesterone, are intricate. Progesterone metabolism in the AIP group differs from that in healthy controls. HCC screening in AIP gene carriers >50 years of age enables early diagnosis and a possibility for curative treatments. Annual HCC screening with liver imaging is recommended in AIP gene carriers >50 years of age.
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| 40. |
- Innala, Eva, et al.
(författare)
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Evaluation of gonadotropin-releasing hormone agonist treatment for prevention of menstrual-related attacks in acute porphyria
- 2010
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Ingår i: Acta Obstetricia et Gynecologica Scandinavica. - : Wiley. - 0001-6349 .- 1600-0412. ; 89:1, s. 95-100
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To describe the benefits and adverse effects of gonadotropin-releasing hormone (GnRH) agonist treatment for prevention of recurrent menstrual attacks in women with acute intermittent porphyria and variegate porphyria. To describe concomitant add-back therapies with estradiol and progesterone and describe their benefits and adverse effects. DESIGN: A retrospective follow-up with questionnaires, interviews and medical records. SETTING: Out-patient care at the Umeå University Hospital in Sweden. POPULATION: Sixteen Caucasian women with DNA-diagnosed porphyria and menstrual-cycle-related porphyria attacks were treated with GnRH agonists during 1984-2000. Fourteen women participated. The mean age when treatment started was 33 years (17-48 years). The duration of treatment varied between 5 months and 9 years. METHODS: GnRH agonists were administered by the intranasal route or by injections. To reduce menopausal symptoms, add-back therapy with low doses of estradiol was administered, and for endometrial protection progesterone was usually administered. MAIN OUTCOME MEASURES: Treatment effects and adverse events as detected in questionnaires, interviews and medical records. RESULTS: Eleven women reported benefits from GnRH agonist treatment with less intense and/or less frequent porphyria attacks, and in four of them attacks almost disappeared. Two women reported no change. One woman had only temporary improvement. Porphyria attacks were triggered by solely estradiol add-back in two women and in five of nine women when progesterone was given. CONCLUSIONS: GnRH agonist treatment can ameliorate menstrual-cycle-related attacks of porphyria. Dose findings for GnRH agonists and add-back regimes especially for progesterone are intricate.
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| 41. |
- Innala, Eva, et al.
(författare)
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Women with acute intermittent porphyria have a defect in 5 alpha-steroid production during the menstrual cycle
- 2012
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Ingår i: Acta Obstetricia et Gynecologica Scandinavica. - : John Wiley & Sons. - 0001-6349 .- 1600-0412. ; 91:12, s. 1445-1452
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Tidskriftsartikel (refereegranskat)abstract
- Objective. To measure serum concentrations of progesterone, estradiol and 5 alpha- and 5 beta-reduced progesterone metabolites in the follicular and luteal phases of the menstrual cycle in women with latent acute intermittent porphyria and manifest acute intermittent porphyria in comparison with healthy control women. Design. A descriptive study with repeated measurements during a complete, ovulatory menstrual cycle. Setting. University hospital out-patient clinic. Population. Thirty-two women with DNA-diagnosed acute intermittent porphyria and 20 healthy control women. Methods. Blood samples for serum progesterone, estradiol, allopregnanolone and pregnanolone were drawn on predefined menstrual cycle days, twice in the follicular phase and three times in the luteal phase. Serum levels of estradiol and progesterone were analysed with commercial kits. Allopregnanolone and pregnanolone levels were analysed with radioimmunoassay following diethylether extraction and celite column chromatography. Main outcome measures. Changes in serum levels of progesterone, estradiol, allopregnanolone and pregnanolone throughout the menstrual cycle. Results. Women with acute intermittent porphyria displayed lower serum concentrations of allopregnanolone in comparison with healthy control women, the difference being most prominent in the luteal phase (p < 0.001). Levels of pregnanolone did not differ significantly between groups. No significant difference was found between women with latent acute intermittent porphyria and manifest acute intermittent porphyria. Conclusions. Decreased levels of the 5 alpha-reduced progesterone metabolite allopregnanolone were found in the menstrual cycle of women with acute intermittent porphyria. This has not been reported previously and could indicate a reduced 5 alpha-reductase type 1 capacity in the ovary and liver among these women.
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| 42. |
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| 43. |
- Langeland, Markus, et al.
(författare)
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Dietary lysine requirement of juvenile Eurasian Perch (Perca fluviatalis)
- 2014
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Ingår i: Journal of FisheriesSciences.com. - : Scitechnol Biosoft Pvt. Ltd.. - 1307-234X. ; 8, s. 161-175
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to estimate the optimum dietary lysine requirement of juvenile Eura-sian perch (Perca fluviatalis), and to investigate the influence of different dietary lysine levels on growth, carcass composition, somatic indices and haematocrit value. A total of 240 juvenile perch was included in a 12-week feeding study. Based on the whole body amino acid profile of in total 48 perch of three different weight groups, eight semi-purified diets containing graded levels of lysine (L1-L8) were produced. The diets contained approximately 12% crude lipid and 40% crude protein and the lysine level varied from 12.2 (L1) to 24.3 (L8) g kg-1 dry matter (DM). Approximately 40% of the total nitrogen content in the diets was in the form of protein-bound amino acids. The ideal protein concept was applied for estimation of the amino acid re-quirements. Fish fed diets L5-L8 (18.3-24.3 g lysine kg-1 DM) had higher final body weight, weight gain, protein gain and specific growth rate (P<0.001) than fish fed diets L1-L4 (12.2-17.3 g lysine kg-1 DM). Dietary lysine level did not significantly affect intraperitoneal fat, haematocrit value and carcass composition. The results indicate that the lowest lysine level re-quired for optimal growth performance in Eurasian perch is 18.3 g lysine kg-1 DM.
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| 44. |
- Lidén, Mats, et al.
(författare)
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Alternative user interface devices for improved navigation of CT datasets
- 2011
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Ingår i: Journal of digital imaging. - : Springer. - 0897-1889 .- 1618-727X. ; 24:1, s. 126-134
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Tidskriftsartikel (refereegranskat)abstract
- The workflow in radiology departments has changed dramatically with the transition to digital PACS, especially with the shift from tile mode to stack mode display of volumetric images. With the increasing number of images in routinely captured datasets, the standard user interface devices (UIDs) become inadequate. One basic approach to improve the navigation of the stack mode datasets is to take advantage of alternative UIDs developed for other domains, such as the computer game industry. We evaluated three UIDs both in clinical practice and in a task-based experiment. After using the devices in the daily image interpretation work, the readers reported that both of the tested alternative UIDs were better in terms of ergonomics compared to the standard mouse and that both alternatives were more efficient when reviewing large CT datasets. In the task-based experiment, one of the tested devices was faster than the standard mouse, while the other alternative was not significantly faster. One of the tested alternative devices showed a larger number of traversed images during the task. The results indicate that alternative user interface devices can improve the navigation of stack mode datasets and that radiologists should consider the potential benefits of alternatives to the standard mouse.
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| 45. |
- Lidén, Mats, et al.
(författare)
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Making renal stones change size : impact of CT image post processing and reader variability
- 2011
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Ingår i: European Radiology. - : Springer Science and Business Media LLC. - 0938-7994 .- 1432-1084. ; 21:10, s. 2218-2225
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Tidskriftsartikel (refereegranskat)abstract
- Objectives The objectives of this study were to quantify the impact of image post-processing parameters on the apparent renal stone size, and to quantify the intra- and inter-reader variability in renal stone size estimation. Methods Fifty CT datasets including a renal or ureteral stone were included retrospectively during a prospective inclusion period. Each of the CT datasets was post-processed in different ways regarding slice thickness, slice increment and window setting. In the first part of the study a single reader repeated size estimations for the renal stones using different post-processing parameters. In the intra-reader variability experiment one reader reported size estimations for the same images with a one-week interval. The inter-reader variability data were obtained from 11 readers reporting size estimations for the same renal stones. Results The apparent stone size differed according to image post-processing parameters with the largest mean differences seen with regard to the window settings experiment (1.5 mm, p < 0.001) and slice thickness (0.8 mm, p < 0.001). Changes in parameters introduced a bias and a pseudo-random variability. The inter-reader variability was considerably larger than the intra-reader variability. Conclusion Our results indicate a need for the standardisation of making measurements on CT images.
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| 46. |
- Lidén, Mats, 1974-
(författare)
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The stack mode review of volumetric datasets : applications for urinary stone disease
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- During the last decades the acquisition and visualization of radiological images have rapidly evolved. The increasing amounts of volumetric image data particularly from modern CT systems necessitate a constant evolution of the radiological visualization techniques.The dominating display mode for volumetric images has been the stack mode display since its introduction in computerized image review. In the increasing amounts of image data, the stack mode display needs to be analyzed so that the information content in the high resolution datasets can be transformed into clinically relevant information for the management of the individual patient. In the present thesis some aspects of the stack mode display were analyzed using for the most part the size estimation of urinary stones in unenhanced CT as a model.The estimated size has an important correlation to the prognosis for spontaneous passage of an obstructing ureteral stone. In the present thesis the reader variations in the size estimation of urinary stones were quantified, using different visualization parameters and after an attempt to reduce the variations with a training session for the readers. The influence on the estimated stone size of CT image post processing parameters was quantified. A segmentation algorithm was developed and demonstrated to reduce the reader variability through reader independent computer aid. One limitation of the stack mode display concerns three-dimensional shapes, which was modeled by a comparison between the estimated length and width of urinary stones in two- and three-dimensional segmentation. The increasing number of image slices in the acquisitions introduces a need for efficient navigation of the image volumes. In the present thesis the navigation of CT datasets using different user interface devices was evaluated.The rapid evolution of the MRI and CT systems necessitates a constant refinement and evaluation of the cornerstone for radiological volumetric reviewing – the stack mode display of volumetric datasets.
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| 47. |
- Lidén, Mats, 1976-, et al.
(författare)
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Urinary stone size estimation : a new segmentation algorithm-based CT method
- 2012
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Ingår i: European Radiology. - New York, USA : Springer. - 0938-7994 .- 1432-1084. ; 22:4, s. 731-737
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Tidskriftsartikel (refereegranskat)abstract
- The size estimation in CT images of an obstructing ureteral calculus is important for the clinical management of a patient presenting with renal colic. The objective of the present study was to develop a reader independent urinary calculus segmentation algorithm using well-known digital image processing steps and to validate the method against size estimations by several readers. Fifty clinical CT examinations demonstrating urinary calculi were included. Each calculus was measured independently by 11 readers. The mean value of their size estimations was used as validation data for each calculus. The segmentation algorithm consisted of interpolated zoom, binary thresholding and morphological operations. Ten examinations were used for algorithm optimisation and 40 for validation. Based on the optimisation results three segmentation method candidates were identified. Between the primary segmentation algorithm using cubic spline interpolation and the mean estimation by 11 readers, the bias was 0.0 mm, the standard deviation of the difference 0.26 mm and the Bland-Altman limits of agreement 0.0 +/- 0.5 mm. The validation showed good agreement between the suggested algorithm and the mean estimation by a large number of readers. The limit of agreement was narrower than the inter-reader limit of agreement previously reported for the same data. The size of kidney stones is usually estimated manually by the radiologist. An algorithm for computer-aided size estimation is introduced. The variability between readers can be reduced. A reduced variability can give better information for treatment decisions.
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| 48. |
- Lundin, Margareta
(författare)
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Aspects on Image Quality in Radiologic Evaluation of the Urinary Tract
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The focus of this document is on image quality as one of the factors fundamental for the diagnostic process. With the rising number of procedures and the trend towards more complicated examinations, urinary tract investigations was chosen in this work as a good clinical model for evaluation of the factors influencing image quality and of the ways of evaluating image quality.In paper I, a method is described for optimisation during the introduction of a new imaging system, with a focus on the maintenance of image quality relative to the older already optimised system. Image quality was assessed using the image criteria of the European guidelines for IVU with visual grading analysis. Equivalent image quality in image pairs was achieved at 30% of the dose. The CDRAD contrast-detail phantom makes it possible to find dose levels that give equal image quality using different imaging systems.In paper II, the influence of bowel purgation on image quality in urography is questioned. The aim of this study was to compare bowel purgation and two other preparation methods; dietary restrictions and no preparation at all. Image quality was assessed according to European Commission criteria for excretory urography. The effectiveness of bowel purgation and the amount of residual gas were scored separately. The results of our study show that the preparation methods are of equal value and further use of bowel purgation before excretory urography cannot be justified.In paper III, the image quality of the non-enhanced series is compared to a virtual noncontrast series obtained using two generations of dual-energy CT scanners and taking CT of the urinary tract as a model. The image quality of the VNC images was rated inferior to the single-energy variant for both scanners, the OR range being 11.5–67.3 for the Definition and 2.1–2.8 for the Definition Flash. Visual noise and overall quality were regarded as better with Flash than with Definition. Image quality of VNC images obtained with the new generation of DECT is still slightly inferior compared to native images.In paper IV, the accuracy of measurement of renal calculi in a dual-energy, virtual, nonenhanced-image series is compared to actual stone size and a single-energy image series in the phantom study. This study shows that detection of small stones is not reliable, despite better image quality, with the new DECT and that small stones will be missed with VNC imaging. With larger stones, the inherent measurement error with CT is magnified with VNC imaging.
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| 49. |
- Lundin, Margareta, et al.
(författare)
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Virtual non-contrast dual-energy CT compared to single-energy CT of the urinary tract : a prospective study
- 2012
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Ingår i: Acta Radiologica. - : Informa Healthcare. - 0284-1851 .- 1600-0455. ; 53:6, s. 689-694
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Tidskriftsartikel (refereegranskat)abstract
- Background: Dual-energy computed tomography (DECT) has been shown to be useful for subtracting bone or calcium in CT angiography and gives an opportunity to produce a virtual non-contrast-enhanced (VNC) image from a series where contrast agents have been given intravenously. High noise levels and low resolution have previously limited the diagnostic value of the VNC images created with the first generation of DECT. With the recent introduction of a second generation of DECT, there is a possibility of obtaining VNC images with better image quality at hopefully lower radiation dose compared to the previous generation.Purpose: The aim of this study is to compare the image quality of the single-energy series to a VNC series obtained with a two generations of DECT scanners. CT of the urinary tract was used as a model.Material and Methods: Thirty patients referred for evaluation of haematuria were examined with an older system (Somatom Definition) and another 30 patients with a new generation (Somatom Definition Flash). One single-energy series was obtained before and one dual-energy series after administration of intravenous contrast media. We created a VNC series from the contrast-enhanced images. Images were assessed concerning image quality with a visual grading scale evaluation of the VNC series with the single-energy series as gold standard.Results: The image quality of the VNC images was rated inferior to the single-energy variant for both scanners, OR range 11.5-67.3 for the Definition and OR 2.1-2.8 for the Definition Flash. Visual noise and overall quality were regarded as better with Flash than Definition.Conclusions: Image quality of VNC images obtained with the new generation of DECT is still slightly inferior compared to native images. However the difference is smaller with the new compared to the older system.
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| 50. |
- Malmqvist, Tove, et al.
(författare)
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A Swedish environmental rating tool for buildings
- 2011
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Ingår i: Energy. - : Elsevier BV. - 0360-5442 .- 1873-6785. ; 36:4, s. 1893-1899
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Tidskriftsartikel (refereegranskat)abstract
- In 2003, a joint effort between the Swedish government, a number of companies in the building and construction sectors, some municipalities, insurance companies and banks set a target that by 2009, all new buildings and 30% of existing Swedish buildings should be rated using a voluntary environmental rating tool. In a major research programme finished in 2008, a tool was developed to be used in this context. The tool covers three assessment areas: Energy, Indoor environment and Material & Chemicals. These areas are split into 11 aspects with one or a few indicators. Rating criteria are specified for each indicator, stipulating requirements for a rating Gold, Silver, Bronze and Rated. Indicator results can then be aggregated to aspect, area and a single raring for building level for enhanced result communication. The tool builds on previous experiences regarding environmental building rating tools and therefore includes some special characteristics which aim to tackle some of the criticism directed towards the first generation of such tools. At the time of writing, the first buildings have received official ratings and an independent stakeholder group is promoting broader implementation of the tool. (C) 2010 Elsevier Ltd. All rights reserved.
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