| 1. |
- Johansson, Åsa, 1981-, et al.
(author)
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Angiostatic factors normally restrict islet endothelial cell proliferation and migration : implications for islet transplantation
- 2009
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In: Transplant International. - : Frontiers Media SA. - 0934-0874 .- 1432-2277. ; 22:12, s. 1182-1188
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Journal article (peer-reviewed)abstract
- New blood vessel formation in transplanted islets occurs within 7-14 days posttransplantation through both the expansion of donor islet endothelium and ingrowth of blood vessels from the implantation organ. However, several studies indicate that although the islets attract recipient blood vessels, the formed intra-islet vascular network is insufficient, which affects islet posttransplant function. This study aimed to develop an in vitro model to investigate the migration and proliferation properties of isolated liver and islet endothelium. Rat islet or liver endothelium was purified using Bandeiraea simplicifolia (BS-1)-coated Dynabeads. The liver endothelium displayed an increased migration towards islet-conditioned medium, and this chemo-attractant effect was fully prevented by adding a neutralizing vascular endothelial growth factor (VEGF)-antibody. In contrast, islet-produced VEGF failed to induce islet endothelial cell migration and only had marginal effects on islet endothelial cell proliferation. These properties could, however, be activated through blocking the effects of either endostatin, thrombospondin-1 or α1-antitrypsin. In conclusion, VEGF may attract recipient blood vessels towards intrahepatically transplanted islets, but intra-islet vascular expansion is hampered by angiostatic factors present within the islets and the islet endothelium. Inhibition of these early after transplantation may provide a strategy to restore the islet vascular network and improve islet graft function.
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| 2. |
- Andersson, Magnus, et al.
(author)
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Structural Dynamics of Light-Driven Proton Pumps
- 2009
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In: Structure. - : Elsevier BV. - 0969-2126 .- 1878-4186. ; 17:9, s. 1265-1275
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Journal article (peer-reviewed)abstract
- Bacteriorhodopsin and proteorhodopsin are simple heptahelical proton pumps containing a retinal chromophore covalently bound to helix G via a protonated Schiff base. Following the absorption of a photon, all-trans retinal is isomerized to a 13-cis conformation, initiating a sequence of conformational changes driving vectorial proton transport. In this study we apply time-resolved wide-angle X-ray scattering to visualize in real time the helical motions associated with proton pumping by bacteriorhodopsin and proteorhodopsin. Our results establish that three conformational states are required to describe their photocycles. Significant motions of the cytoplasmic half of helix F and the extracellular half of helix C are observed prior to the primary proton transfer event, which increase in amplitude following proton transfer. These results both simplify the structural description to emerge from intermediate trapping studies of bacteriorhodopsin and reveal shared dynamical principles for proton pumping.
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| 3. |
- Barros, Gustavo Gil, 1976-
(author)
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Influence of Substrate Topography on Ink Distribution in Flexography
- 2006
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Doctoral thesis (other academic/artistic)abstract
- The printability of paper in flexography is largely dependent on the topographical characteristics of the substrate. Topography imaging instruments make it possible to obtain three-dimensional scans of paper surfaces that can be further used to calculate valuable quality parameters. The primary aim of the work described in this thesis has been to identify and isolate structural properties of the paper surface which significantly influence the ink distribution during printing and limit the subsequently attainable print quality.OptiTopo is an optical imaging technique which provides precise and fast topographic scans of both printed and unprinted paper surfaces. The potential and limitations of the technique have been evaluated. The optical requirements on the substrate for an accurate and precise topographic scan were determined. Detail-rendering was substantially improved using a custom-designed restoring filter, and a new enhanced spatial resolution range was established. A combination of further algorithm improvements made it possible also to obtain reflectance-factor-calibrated intensity images of scanned printed surfaces.Serious deficiencies affecting the quality of flexographic prints may appear in the form of local unprinted areas (UCA) in a full-tone print, generally caused by incomplete ink transfer. An algorithm detecting and quantifying local uncovered area was developed, tested and successfully integrated with the OptiTopo instrument. A UCA occurrence frequency distribution, indicating the percentage of the uncovered area at a certain topographical elevation, was calculated for different prints. The topographic characteristics of the uncovered areas clearly indicate that surface depressions are the primary cause of uncovered areas in flexographic printing.Four different predictive models based on topography thresholding were proposed and tested using two independent quality judgement criteria. These quality indices took into account both the amount and location of the predictions. A deeper understanding of the topographical features governing UCA occurrence was established with a proposed ink bridging effect. The total risk of non-ink-covered areas in flexography printing due to topographical features was estimated.The overall influence of paper topography on the flexography printability of full-tone areas was studied and its importance for the ink distribution assessed. The impacts of printing plate hardness, printing pressure, anilox cylinder volume and substrate roughness were quantified. Two typical flexography patterns were identified and their origin discussed: sub-millimetre elongated structures and millimetre-scale blotches.
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| 4. |
- de Almeida Cadorin, Eduardo, 1976-, et al.
(author)
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Future Challenges for Science Parks : Attractiveness and Recruitment of Talents
- 2016
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Conference paper (other academic/artistic)abstract
- Science parks have from the very beginning been important and valuable tools for the development of knowledge intensive economies. Most science parks have also strongly attracted talents, ideas, capital, R&D and firms. During the past decades we have witnessed a number of other structures and organizations being established, i.e. innovation hubs, clusters and so forth. We have also seen a very clear trend that the science parks abandon the idea of being strict geographical locations and become more of a function in the city. One issue that quite recently has been recognized, connected to science park development, is the potential they have as attracters of talented individuals. The starting point is, which goes in line with Richard Florida and his thoughts about the “Creative class”, that regions´ ability to attract firms and human capital is a key in their economic development. Talent individuals will undertake entrepreneurial activities and building values for the environment in which they are operating.
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| 5. |
- Ekblom Bak, Elin, 1981-, et al.
(author)
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Accelerometer derived physical activity patterns in 27.890 middle‐aged adults : The SCAPIS cohort study
- 2022
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In: Scandinavian Journal of Medicine and Science in Sports. - : John Wiley & Sons. - 0905-7188 .- 1600-0838. ; 32:5, s. 866-880
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Journal article (peer-reviewed)abstract
- The present study aims to describe accelerometer-assessed physical activity (PA) patterns and fulfillment of PA recommendations in a large sample of middle-aged men and women, and to study differences between subgroups of socio-demographic, socio-economic, and lifestyle-related variables. A total of 27 890 (92.5% of total participants, 52% women, aged 50–64 years) middle-aged men and women with at least four days of valid hip-worn accelerometer data (Actigraph GT3X+, wGT3X+ and wGT3X-BT) from the Swedish CArdioPulmonary bioImage Study, SCAPIS, were included. In total, 54.5% of daily wear time was spent sedentary, 39.1% in low, 5.4% in moderate, and only 0.1% in vigorous PA. Male sex, higher education, low financial strain, born in Sweden, and sedentary/light working situation were related to higher sedentary time, but also higher levels of vigorous PA. High BMI and having multiple chronic diseases associated strongly with higher sedentary time and less time in all three PA intensities. All-year physically active commuters had an overall more active PA pattern. The proportion fulfilling current PA recommendations varied substantially (1.4% to 92.2%) depending on data handling procedures and definition used. Twenty-eight percent was defined as having an “at-risk” behavior, which included both high sedentary time and low vigorous PA. In this large population-based sample, a majority of time was spent sedentary and only a fraction in vigorous PA, with clinically important variations between subgroups. This study provides important reference material and emphasizes the importance of a comprehensive assessment of all aspects of the individual PA pattern in future research and clinical practice.
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| 6. |
- Fjellström, Magnus, 1976-, et al.
(author)
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A comparative study of assesment in school and in work based learning
- 2010
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In: Proceeding of EARLI SIG 14 Learning and Professional Development Conference. - München : Ludwig-Maximilians-Universität.
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Conference paper (peer-reviewed)abstract
- In a wide perspective this study deals with the high complexity when assessing students in vocational education, exemplified from Carpenter education in a Swedish Upper Secondary School. The aim was to describe and analyze the view of student assessment among Subject Teachers, Vocational Teachers and Instructors at construction sites. Questions asked were; what procedure does the respective teacher category use when carrying out assessments? What kind of knowledge was valued and what type of criteria did the three categories use when making their assessments. Data was collected in form of deep interviews with three Subject Teachers, three Vocational Teachers and three Instructors. Generally the findings reveal that assessment in vocational education is a very complex task. More specific the findings show that Subject Teachers value specific subject knowledge high while the Instructors prefer more general knowledge. Between those two the Vocational Teacher can be found who has to consider both demands from the school and workplace when making their student assessments. The results also indicate that beside the result from written tests the Subject Teachers take problem solving ability and ambition into account when setting grades. The Vocational Teacher do not value written tests but consider self government, knowledge of the process, quality consciousness, aid facilities and self image as valuable key competences. The Instructors view ambition and self knowledge as most valuable when making their assessments.
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| 7. |
- Grahn, Tonje, 1976-
(author)
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Risk assessment of natural hazards : Data availability and applicability for loss quantification
- 2017
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Doctoral thesis (other academic/artistic)abstract
- Quantitative risk assessments are a fundamental part of economic analysis and natural hazard risk management models. It increases the objectivity and the transparency of risk assessments and guides policymakers in making efficient decisions when spending public resources on risk reduction. Managing hazard risks calls for an understanding of the relationships between hazard exposure and vulnerability of humans and assets. The purpose of this thesis is to identify and estimate causal relationships between hazards, exposure and vulnerability, and to evaluate the applicability of systematically collected data sets to produce reliable and generalizable quantitative information for decision support. Several causal relationships have been established. For example, the extent of lake flood damage to residential buildings depends on the duration of floods, distance to waterfront, the age of the house and in some cases the water level. Results also show that homeowners private initiative to reduce risk, prior to or during a flood, reduced their probability of suffering building damage with as much as 40 percent. Further, a causal relationship has been established between the number of people exposed to quick clay landslides and landslide fatalities. Even though several relationships were identified between flood exposure and vulnerability, the effects can only explain small parts of the total variation in damages, especially at object level. The availability of damage data in Sweden is generally low. The most comprehensive damage data sets in Sweden are held by private insurance companies and are not publicly available. Data scarcity is a barrier to quantitative natural hazard risk assessment in Sweden. More efforts should therefore be made to collect data systematically for modelling and validating standardized approaches to quantitative damage estimation.
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| 8. |
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| 9. |
- Johansson, Helena, 1971-, et al.
(author)
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Algebra discourse in mathematics and physics textbooks for upper secondary school
- 2021
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In: Proceedings of the 44<sup>th</sup> Conference of the International Group for the Psychology of Mathematics Education, Vol.1. - Khon Kaen, Thailand : PME. ; , s. 149-149
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Conference paper (peer-reviewed)abstract
- For many students, algebra is one of the most difficult areas of mathematics, and limited algebra knowledge, particularly concerning algebraic symbols, can hinder students’ successin other areas, such as physics (Pospiech, et.al., 2019). In a Swedish context, algebra and algebraic symbols are usually introduced in grades 7-9 (age 13-15), and are then taken for granted in grades 10-12, also in physics. Thus, it is important to identify similarities and differences in how algebra is taught and used in the different contexts of mathematics and physics. This pilot study, focusing on the use of algebraic symbols, is part of a larger project contributing to a more holistic view of students’ algebraic knowledge in different parts of the educational system. We take a discourse perspective, where the algebraic discourse is characterized by the word-use and visual mediators (e.g., symbols), among other things (Sfard, 2008).We analysed common Swedish textbooks for the first physics course and the first mathematics course at upper secondary level (grade 10). Content of both textbooks was categorized with respect to, for example, symbols that were used (e.g., Latin or Greek letters), number of different and similar symbols in symbolic expressions, words used to address (part of) symbolic expressions, and overall mathematical context of the symbolic expression (e.g., calculation with a fixed value or derivation of one expression from another). Preliminary results, here delimited to differences, show that on average it is a greater number of different symbols in expressions in the physics textbook compared to mathematics. Calculations with specific values are more common in physics, whereas it is more common that algebraic entities relate to each other in mathematics. In mathematics, more than half of the symbolic expressions are never referred to using words, while the same is true in physics for 18% ofthe expressions. Commonly used physics words in the mathematics textbook were time and distance, while time was not common in the physics textbook, when referring to symbolic expressions. These differences imply that students meet different algebra discourses in mathematics and physics. Thus, it can be hard for them to identify these discourses as “the same mathematics”. By being aware of these differences, teachers can facilitate students’ use of algebra, and in the long run, students’ learning in both mathematics and physics.ReferencesPospiech, G., Michelini, M., & Eylon, B-S. (Eds.). (2019). Mathematics in physics education.Springer. https://doi.org/10.1007/978-3-030-04627-9.Sfard, A. (2008). Thinking as communicating: Human development, the growth of discoursesand mathematizing. Cambridge University Press.
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| 10. |
- Johansson, Helena, 1971-, et al.
(author)
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Matematik-app för elever och lärare
- 2022
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Reports (other academic/artistic)abstract
- Denna rapport utgör ett resultat från projektet ”Matematik-app för elever och lärare”, som var en samverkan mellan Mittuniversitetet och Örnsköldsviks kommun. I detta projekt genomfördes en utvärdering av matematikappen Vektor, både ur elevperspektiv och lärarperspektiv. Det övergripande syftet med projektet var att bidra till en utveckling av matematikundervisningen för yngre elever, från förskoleklass till årskurs 3 (F-3). Analyser genomfördes som fokuserade på hur appen kan användas som stöd för elevers lärande kring tallinjen och taluppfattning samt hur appen kan användas som stöd för lärares arbete med planering och utveckling av undervisningen kring detta matematikinnehåll. Resultaten påvisar flera möjligheter till att använda appen i matematikundervisningen men att det också finns vissa spänningar mellan appens egenskaper och lärares behov. Detta leder till att lärarna inte använder appen utifrån instruktionerna som anges av appens tillverkare, utan de gör visst motstånd och anpassar användningen.Denna rapport har granskats och diskuterats på ett högre seminarium inom Nätverk för Ämnesdidaktisk forskning i Matematik och Naturvetenskap (NÄMN) vid Mittuniversitetet.
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