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  • 451.
    Aghbolagh, Mahdi Shahmohammadi
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Meynaq, Mohammad Yaser Khani
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Shimizu, Kenichi
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Lindholm-Sethson, Britta
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Aspects on mediated glucose oxidation at a supported cubic phase2017In: Bioelectrochemistry, ISSN 1567-5394, E-ISSN 1878-562X, Vol. 118, p. 8-13Article in journal (Refereed)
    Abstract [en]

    A supported liquid crystalline cubic phase housing glucose oxidase on an electrode surface has been suggested as bio-anode in a biofuel. The purpose of this investigation is to clarify some aspect on the mediated enzymatic oxidation of glucose in such a bio-anode where the mediator ferrocene-carboxylic acid and glucose were dissolved in the solution. The enzyme glucose oxidase was housed in the water channels of the mono-olein cubic phase. The system was investigated with cyclic voltammetry at different scan rates and the temperature was varied between 15 degrees C and 30 degrees C. The diffusion coefficient of the mediator and also the film resistance was estimated showing a large decrease in the mass-transport properties as the temperature was decreased. The current from mediated oxidation of glucose at the electrode surface increased with decreasing film thickness. The transport of the mediator in the cubic phase was the rate-limiting step in the overall reaction, where the oxidation of glucose took place at the outer surface of the cubic phase.

  • 452.
    Aghester, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Hyperspektral bildanalys av pulverblandningar innehållande mannitol och natriumsalicylat: Effekt av partikelstorlek och blandningstid2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 453.
    Aglar, Öznur
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Design and synthesis of inhibitors of the ADP ribosylating toxin ExoS: Targeting the Type III Secretion System (T3SS) of Pseudomonas aeruginosa.2016Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
  • 454.
    Aglert, Katja
    et al.
    Umeå University, Faculty of Arts, Umeå Academy of Fine Arts.
    Norberg, MicaelUmeå University, Faculty of Arts, Umeå Academy of Fine Arts.
    Sleeping with ghosts: Kandidatutställning 20192019Collection (editor) (Other (popular science, discussion, etc.))
  • 455.
    Agliari, Anna
    et al.
    Catholic University of Milano, Italy.
    Gardini, Laura
    University of Urbino, Italy.
    Puu, Tönu
    Umeå University, Faculty of Social Sciences, Centre for Regional Science (CERUM).
    Global Bifurcations in Duopoly when the Cournot Point is Destabilized through a Subcritical Neimark Bifurcation2003Report (Other academic)
    Abstract [en]

    An adaptive oligopoly model, where the demand function is isoelastic and the competitors operate under constant marginal costs, is considered. The Cournot equilibrium point then loses stability through a subcritical Neimark bifurcation. The present paper focuses some global bifurcations, which precede the Neimark bifurcation, and produce other attractors which coexist with the still attractive Cournot fixed point.

  • 456.
    Agliari, Anna
    et al.
    Dip. Scienze Economiche e Sociali, Catholic University.
    Gardini, Laura
    Dip. Scienze Economiche, University of Urbino .
    Puu, Tönu
    Umeå University, Faculty of Social Sciences, Department of Economics. Umeå University, Faculty of Social Sciences, Centre for Regional Science (CERUM).
    Global bifurcations in duopoly when the Cournot Point is destabilized through a subcritical Neimark bifurcation2006In: International Game Theory Review, ISSN 0219-1989, Vol. 8, no 1, p. 1-20Article in journal (Refereed)
  • 457.
    Agliari, Anna
    et al.
    Univ Cattolica Sacro Cuore, Ist Econometria & Matematica, Italy.
    Gardini, Laura
    University of Urbino, Dept of Economics, Italy.
    Puu, Tönu
    Umeå University, Faculty of Social Sciences, Centre for Regional Science (CERUM). Umeå University, Faculty of Social Sciences, Department of Economics.
    Global bifurcations of basins in a triopoly game2002In: International Journal of Bifurcation and Chaos in Applied Sciences and Engineering, ISSN 0218-1274, Vol. 12, no 10, p. 2175-2207Article in journal (Refereed)
    Abstract [en]

    A Cournot model based on bounded inverse demand function and constant marginal production costs is studied. The case of three producers is considered and the adjustment process reduces to a three-dimensional noninvertible map in the output of competitors. The analysis of the dynamical behavior of the map is performed by the "critical curve method", extended to the critical surfaces in 3D. By this method, we explain the different bifurcations in the basins of attraction and in the attracting sets. In particular, given the economic application, feasible trajectories are focused, starting from the simple situation of two identical producers and extending the results to the generic case.

  • 458.
    Agliari, Anna
    et al.
    Catholic University, Dipartimento di Scienze Economiche e Sociali, Piacenza, Italy.
    Gardini, Laura
    Dept. Scienze Economiche, University of Urbino, Italy.
    Puu, Tönu
    Umeå University, Faculty of Social Sciences, Centre for Regional Science (CERUM).
    Some global bifurcations related to the appearance of closed invariant curves2005In: Mathematics and Computers in Simulation, ISSN 0378-4754, E-ISSN 1872-7166, Vol. 68, no 3, p. 201-219Article in journal (Refereed)
    Abstract [en]

    In this paper, we consider a two-dimensional map (a duopoly game) in which the fixed point is destabilized via a subcritical Neimark–Hopf (N–H) bifurcation. Our aim is to investigate, via numerical examples, some global bifurcations associated with the appearance of repelling closed invariant curves involved in the Neimark–Hopf bifurcations. We shall see that the mechanism is not unique, and that it may be related to homoclinic connections of a saddle cycle, that is to a closed invariant curve formed by the merging of a branch of the stable set of the saddle with a branch of the unstable set of the same saddle. This will be shown by analyzing the bifurcations arising inside a periodicity tongue, i.e., a region of the parameter space in which an attracting cycle exists.

  • 459.
    Agliari, Anna
    et al.
    Dipartimento di Scienze Economiche e Sociali, Catholic University.
    Gardini, Laura
    Dept. Scienze Economiche, University of Urbino.
    Puu, Tönu
    Umeå University, Faculty of Social Sciences, Department of Economics. Umeå University, Faculty of Social Sciences, Centre for Regional Science (CERUM).
    Some global bifurcations related to the apperance of closed invariant curves2005In: Mathematics and Computers in Simulations, ISSN 0378-4754, Vol. 68, no 3, p. 201-219Article in journal (Refereed)
    Abstract [en]

    In this paper, we consider a two-dimensional map (a duopoly game) in which the fixed point is destabilized via a subcritical Neimark–Hopf (N–H) bifurcation. Our aim is to investigate, via numerical examples, some global bifurcations associated with the appearance of repelling closed invariant curves involved in the Neimark–Hopf bifurcations. We shall see that the mechanism is not unique, and that it may be related to homoclinic connections of a saddle cycle, that is to a closed invariant curve formed by the merging of a branch of the stable set of the saddle with a branch of the unstable set of the same saddle. This will be shown by analyzing the bifurcations arising inside a periodicity tongue, i.e., a region of the parameter space in which an attracting cycle exists.

  • 460.
    Agliari, Anna
    et al.
    Catholic University in Milan, Italy/University of Parma, Italy.
    Gardini, Laura
    University of Parma, Italy/Istituto di Scienze Economiche, University of Urbino, Italy.
    Puu, Tönu
    Umeå University, Faculty of Social Sciences, Department of Economics.
    The dynamics of a triopoly Cournot game2000In: Chaos, Solitons & Fractals, ISSN 0960-0779, E-ISSN 1873-2887, Vol. 11, no 15, p. 2531-2560Article in journal (Refereed)
    Abstract [en]

    This paper reconsiders the Cournot oligopoly (noncooperative) game with iso-elastic demand and constant marginal costs, one of the rare cases where the reaction functions can be derived in closed form. It focuses the case of three competitors, and so also extends the critical line method for non-invertible maps to the study of critical surfaces in 3D. By this method the various bifurcations of the attractors and their basins are studied. As a special case the restriction of the map to an invariant plane when two of the three firms are identical is focused.

  • 461.
    Agliari, Anna
    et al.
    Catholic University, Faculty of Economics, Milan, Italy.
    Puu, Tönu
    Umeå University, Faculty of Social Sciences, Centre for Regional Science (CERUM).
    A Cournot duopoly model with bounded demand2002Book (Other academic)
  • 462.
    Agliari, Anna
    et al.
    Univ Sacred Heart, Ist Econometria & Matemat, Milan.
    Puu, Tönu
    Umeå University, Faculty of Social Sciences, Department of Economics.
    A Cournot duopoly with bounded inverse demand function2002In: OLIGOPOLY DYNAMICS: MODELS AND TOOLS, BERLIN: SPRINGER-VERLAG BERLIN , 2002, p. 171-194Conference paper (Other academic)
  • 463.
    Aglund, Kristina
    et al.
    Umeå University, Faculty of Medicine, Radiation Sciences, Oncology.
    Rauvala, Marita
    Puistola, Ulla
    Ångström, Tord
    Umeå University, Faculty of Medicine, Medical Biosciences.
    Turpeenniemi-Hujanen, Taina
    Zackrisson, Björn
    Umeå University, Faculty of Medicine, Radiation Sciences, Oncology.
    Stendahl, Ulf
    Umeå University, Faculty of Medicine, Radiation Sciences, Oncology.
    Gelatinases A and B (MMP-2 and MMP-9) in endometrial cancer-MMP-9 correlates to the grade and the stage2004In: Gynecol Oncol, ISSN 0090-8258, Vol. 94, no 3, p. 699-704Article in journal (Refereed)
  • 464. Agmon-Levin, Nancy
    et al.
    Damoiseaux, Jan
    Kallenberg, Cees
    Sack, Ulrich
    Witte, Torsten
    Herold, Manfred
    Bossuyt, Xavier
    Musset, Lucille
    Cervera, Ricard
    Plaza-Lopez, Aresio
    Dias, Carlos
    Sousa, Maria Jose
    Radice, Antonella
    Eriksson, Catharina
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Immunology.
    Hultgren, Olof
    Viander, Markku
    Khamashta, Munther
    Regenass, Stephan
    Coelho Andrade, Luis Eduardo
    Wiik, Allan
    Tincani, Angela
    Ronnelid, Johan
    Bloch, Donald B.
    Fritzler, Marvin J.
    Chan, Edward K. L.
    Garcia-De la Torre, I.
    Konstantinov, Konstantin N.
    Lahita, Robert
    Wilson, Merlin
    Vainio, Olli
    Fabien, Nicole
    Sinico, Renato Alberto
    Meroni, Pierluigi
    Shoenfeld, Yehuda
    International recommendations for the assessment of autoantibodies to cellular antigens referred to as anti-nuclear antibodies2014In: Annals of the Rheumatic Diseases, ISSN 0003-4967, E-ISSN 1468-2060, Vol. 73, no 1, p. 17-23Article in journal (Refereed)
    Abstract [en]

    Anti-nuclear antibodies (ANA) are fundamental for the diagnosis of autoimmune diseases, and have been determined by indirect immunofluorescence assay (IIFA) for decades. As the demand for ANA testing increased, alternative techniques were developed challenging the classic IIFA. These alternative platforms differ in their antigen profiles, sensitivity and specificity, raising uncertainties regarding standardisation and interpretation of incongruent results. Therefore, an international group of experts has created recommendations for ANA testing by different methods. Two groups of experts participated in this initiative. The European autoimmunity standardization initiative representing 15 European countries and the International Union of Immunologic Societies/World Health Organization/Arthritis Foundation/Centers for Disease Control and Prevention autoantibody standardising committee. A three-step process followed by a Delphi exercise with closed voting was applied. Twenty-five recommendations for determining ANA (1-13), anti-double stranded DNA antibodies (14-18), specific antibodies (19-23) and validation of methods (24-25) were created. Significant differences between experts were observed regarding recommendations 24-25 (p<0.03). Here, we formulated recommendations for the assessment and interpretation of ANA and associated antibodies. Notably, the roles of IIFA as a reference method, and the importance of defining nuclear and cytoplasmic staining, were emphasised, while the need to incorporate alternative automated methods was acknowledged. Various approaches to overcome discrepancies between methods were suggested of which an improved bench-to-bedside communication is of the utmost importance. These recommendations are based on current knowledge and can enable harmonisation of local algorithms for testing and evaluation of ANA and related autoantibodies. Last but not least, new more appropriate terminologies have been suggested.

  • 465. Agnafors, Marcus
    et al.
    Amnå, Erik
    Bergman, Torbjörn
    Umeå University, Faculty of Social Sciences, Department of Political Science.
    Bexell, Magdalena
    Stubbergaard, Ylva
    Wihlborg, Elin
    von Sydow, Björn
    Kommentarer till Johan P. Olsen, "Lorenzettis utfordring og demokratiets århundre"2015In: Statsvetenskaplig Tidskrift, ISSN 0039-0747, Vol. 117, no 1, p. 38-41Article in journal (Other academic)
  • 466.
    Agnemo, Elin
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Avfall från dricksvattenkvalitetslaboratorium: En studie om avfallsklassning och hantering av m-Endo agar LES vid Stockholm Vatten.2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of the study was to determine how the waste from m-Endo agar LES (LesEndo) should be categorized and managed, due to its content of the carcinogenic substance basic red 9 in basic fuchsine. The information was obtained by studying legislation and a laboratory practical was performed to verify, if basic fuchsine could remain in LesEndo agar after being heated. This was important to know for the further interpretation how to categorize and manage the waste according to the legislation. LesEndo agar was autoclaved at 121 °C for 15 and 30 minutes. E. coli and coliform bacteria was put to grow on the LesEndo agar. The results from the study showed that all replicas had coliform colonies, which appeared with a metallic fuchsine-sheen. This verified that basic fuchsine was unchanged and that there was no significant difference in growth between replicas with heated agar and the control. The total concentration of basic fuchsine in LesEndo agar was 0.08%. To be categorized as hazardous waste the threshold value for basic red 9 is 0.1%. According to a strict interpretation of the legislation, waste from used LesEndo agar should not be categorized and managed as hazardous waste. However, evaporation has to be taken into consideration and the concentration may be above 0.1%. Therefore my evaluation is that waste from used LesEndo agar should be categorized and managed as hazardous waste to protect humans and the environment from being harmed.

  • 467.
    Agnemo, Maja
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Skogen i våra hjärtan: Erfarenheter, emotionella band, värderingar och attityder till skog, natur och allemansrätten2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Swedish landscape is dominated by highly valued forests and stakeholders argue different uses. The aim of this study was to investigate peoples experience, emotional bonds and values of forests and nature, their attitudes towards human utilization of nature and right of public access (allemansrätt), including relationships them in between. All in all 663 university students among who 254 were women and 401 were men, with the mean age of 24, answered a survey. The results from correlations show relationships between all variables. An attitude saying that the right of public access is important was predicted by stronger emotional bonds and spending more time in the forest. An attitude saying that the right of public access should be restricted was predicted by higher valuing of forest production and was more common among forest owners. The results implicate that emotions, which are strong incentives for action and created by experience, should be considered to better accomplish environmental goals. Environments necessary for experiencing nature should be provided, which is today made possible by right of public access to nature. 

  • 468.
    Agnemo, Roland
    Umeå University, Faculty of Science and Technology.
    Ligniners reaktioner med alkalisk väteperoxid1981Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Under alkaline conditions hydrogen peroxide can be used either as a 1ignin-degrading or a 1ignin-preserving bleaching agent. If heavy metal ions are present and/or silicate is absent in the reaction medium, hydrogen peroxide decomposes via hydroxyl radicals and superoxide ions to oxygen and water. These decomposition products are able to react for example with phenolic lignin structures and thereby cause a partial degradation of lignin. In such a system peroxide could act as a bleaching and delignifying agent at the same time and these properties can be utilized for the bleaching of chemical pulps.In order to elucidate the factors which influence the degradation of phenolic structures by oxidation with alkaline hydrogen peroxide the lignin model compounds-methylsyringyl alcohol was studied.By determining the first order reaction rate constants for the oxidation, the main results which were obtained indicate that phenolic lignin structures can be efficiently degraded especially if:A. The pH in the bleaching liquor is close to the pK -valueàfor hydrogen peroxide.B. The ionic strength in the bleaching medium is as high as possible.C. A fixed amount of heavy metal ions (manganese) is added to the bleaching liquor.In the presence of silicate and diethylentriaminepenta-acetic acid (DTPA) hydrogen peroxide is stabilized against decomposition. Under these conditions alkaline hydrogen peroxide is able to react only with lignin units containing conjugated carbonyl groups such as quinone, aryl-oe-carbonyl and cinnamaldehyd structures, leading to an elimination of the chromophoric structures without any substantial dissolution of lignin. In this part of work we have elucidated the kinetic behavior and the reaction products from lignin model compounds of the aryl-of- carbonyl and cinnamaldehyde types.1,2-Diarylpropan-1,3,-diol structures constitute an important building unit in native lignins. We have demonstrated that under hydrogen peroxide bleaching conditions the model compound 2,3--bis(4-hydroxy-3-methoxyphenyl)-3-ethoxy-propanol was converted to stilbenes, ûe. structures which when present in pulps may contribute to a rapid yellowing. The results obtained with model compounds under simulated lignin retaining bleaching conditions demonstrate that there are possibilities to improve the bleaching of mechanical pulps with hydrogen peroxide if:A. The remaining heavy metal ions complexed with DTPA are present in their lowest valence states.B. The concentration of hydroperoxy ions can be maintained at a high level at the lowest possible pH-value.

  • 469.
    Agnig, Rushen Robin
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Business Administration.
    Valutakursrisker: Bestämningsfaktorer för svenska företags användning av finansiella instrument vid hantering av valutakursrisker.2012Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    När ett företag importerar eller exporterar varor och tjänster i utländsk valuta kan de exponera sig mot valutakursrisker. Värdet på en valuta idag är kanske inte densamma imorgon vilket kan både gynna och missgynna företag verksamma inom handel. Världsekonomin utsattes för chocker och en av de värsta finansiella kriser upplevdes under 2009/2010. Eftereffekterna kan fortfarande ses av länder exempelvis lokaliserade i Euroområdet. Valutakurser påverkas av makrorelaterad information vilket kan orsaka stora volatila fluktuationer av kurser som kan leda till enorm ekonomisk skada eller stor ekonomisk vinst för företag. För att studera detta närmare genomfördes en enkätstudie på 100 stycken företag i Sverige som var noterade på stockholmsbörsen och/eller onoterade. Genom de kvantitativa data som samlades in kördes en regressionsanalys i SPSS utifrån en OLS funktion. Modellen hade användande av finansiella instrument som beroende variabel. De oberoende variablerna var; policy för hantering av valutakursrisker, kompetens om finansiella instrument i företaget, extern hjälp, övriga valutakursriskminimeringsstrategier, företagets förhållande till risk, skuldkrisen i Europa, beräkning av kostnader och intäkter, procentuell andel av intäkter i utländskvaluta samt procentuell andel kostnader i utländskvaluta. Sedan kontrollerades materialet för att uppfylla vitala antaganden i modellen. Resultatet testades sedan genom ett t-test. Regressionsanalysen visade vid 5 procents signifikants nivå positiva samband mellan användandet av finansiella instrument vid valutakursriskhantering och att ha en utformad policy för hantering av utländsk valuta. Vidare kunde det även härledas positiva samband vid användande av finansiella instrument samt företagets förhållande till risk. Riskaverta förtag tenderar att använda instrument för att minimera valutakursrisker. Analysen kunde även med 10 procents signifikants nivå härleda negativa samband mellan användandet av finansiella instrument samt hantering av övriga valutakursriskminimeringsstrategier. Studien visar likheter med tidigare forskning och finansiell teori.

  • 470.
    Agnvall, Ahlbin
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Chronic exertional compartment syndrome in patients with diabetes mellitus type 1 - Outcome after surgery in 78 patients2017Independent thesis Basic level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 471. Agogo, George O.
    et al.
    van der Voet, Hilko
    van 't Veer, Pieter
    Ferrari, Pietro
    Muller, David C.
    Sanchez-Cantalejo, Emilio
    Bamia, Christina
    Braaten, Tonje
    Knuppel, Sven
    Johansson, Ingegerd
    Umeå University, Faculty of Medicine, Department of Odontology.
    van Eeuwijk, Fred A.
    Boshuizen, Hendriek C.
    A method for sensitivity analysis to assess the effects of measurement error in multiple exposure variables using external validation data2016In: BMC Medical Research Methodology, ISSN 1471-2288, E-ISSN 1471-2288, Vol. 16, article id 139Article in journal (Refereed)
    Abstract [en]

    Background: Measurement error in self-reported dietary intakes is known to bias the association between dietary intake and a health outcome of interest such as risk of a disease. The association can be distorted further by mismeasured confounders, leading to invalid results and conclusions. It is, however, difficult to adjust for the bias in the association when there is no internal validation data. Methods: We proposed a method to adjust for the bias in the diet-disease association (hereafter, association), due to measurement error in dietary intake and a mismeasured confounder, when there is no internal validation data. The method combines prior information on the validity of the self-report instrument with the observed data to adjust for the bias in the association. We compared the proposed method with the method that ignores the confounder effect, and with the method that ignores measurement errors completely. We assessed the sensitivity of the estimates to various magnitudes of measurement error, error correlations and uncertainty in the literature-reported validation data. We applied the methods to fruits and vegetables (FV) intakes, cigarette smoking (confounder) and all-cause mortality data from the European Prospective Investigation into Cancer and Nutrition study. Results: Using the proposed method resulted in about four times increase in the strength of association between FV intake and mortality. For weakly correlated errors, measurement error in the confounder minimally affected the hazard ratio estimate for FV intake. The effect was more pronounced for strong error correlations. Conclusions: The proposed method permits sensitivity analysis on measurement error structures and accounts for uncertainties in the reported validity coefficients. The method is useful in assessing the direction and quantifying the magnitude of bias in the association due to measurement errors in the confounders.

  • 472. Agogo, George O.
    et al.
    van der Voet, Hilko
    van't Veer, Pieter
    Ferrari, Pietro
    Leenders, Max
    Muller, David C.
    Sanchez-Cantalejo, Emilio
    Bamia, Christina
    Braaten, Tonje
    Knueppel, Sven
    Johansson, Ingegerd
    Umeå University, Faculty of Medicine, Department of Odontology.
    van Eeuwijk, Fred A.
    Boshuizen, Hendriek
    Use of Two-Part Regression Calibration Model to Correct for Measurement Error in Episodically Consumed Foods in a Single-Replicate Study Design: EPIC Case Study2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 11, p. e113160-Article in journal (Refereed)
    Abstract [en]

    In epidemiologic studies, measurement error in dietary variables often attenuates association between dietary intake and disease occurrence. To adjust for the attenuation caused by error in dietary intake, regression calibration is commonly used. To apply regression calibration, unbiased reference measurements are required. Short-term reference measurements for foods that are not consumed daily contain excess zeroes that pose challenges in the calibration model. We adapted twopart regression calibration model, initially developed for multiple replicates of reference measurements per individual to a single-replicate setting. We showed how to handle excess zero reference measurements by two-step modeling approach, how to explore heteroscedasticity in the consumed amount with variance-mean graph, how to explore nonlinearity with the generalized additive modeling (GAM) and the empirical logit approaches, and how to select covariates in the calibration model. The performance of two-part calibration model was compared with the one-part counterpart. We used vegetable intake and mortality data from European Prospective Investigation on Cancer and Nutrition (EPIC) study. In the EPIC, reference measurements were taken with 24-hour recalls. For each of the three vegetable subgroups assessed separately, correcting for error with an appropriately specified two-part calibration model resulted in about three fold increase in the strength of association with all-cause mortality, as measured by the log hazard ratio. Further found is that the standard way of including covariates in the calibration model can lead to over fitting the two-part calibration model. Moreover, the extent of adjusting for error is influenced by the number and forms of covariates in the calibration model. For episodically consumed foods, we advise researchers to pay special attention to response distribution, nonlinearity, and covariate inclusion in specifying the calibration model.

  • 473.
    Agorelius, Emma
    et al.
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Business Administration.
    Ek, Anna
    Immateriella tillgångars inverkan på ett företags finansiering: En studie på onoterade svenska företag2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    I takt med att samhällsekonomin har blivit mer kunskapsbaserad har ett företags immateriella tillgångar fått en allt mer betydelsefull roll. Immateriella tillgångar medför dock flera aspekter av osäkerhet, bland annat hur äganderätten ska bestämmas, hur ett tillförlitligt värde ska beräknas samt vilka kriterier som ska gälla för att få ta upp den till redovisning. Svårigheten och komplexiteten detta innebär har gjort att företagens finansiella rapporter har i vissa avseenden tappat sin relevans, exempelvis användbarheten kopplat till externa parters beslutsfattande. Syftet med vår studie är att undersöka om det finns ett samband mellan ett företags tillgångsstruktur och den skuldränta företaget betalar till kreditgivare för sina lån, men även hur tillgångsstrukturen påverkar företagens finansieringsmöjligheter.

    Vetenskapliga utgångspunkter för vår studie är en ontologisk verklighetssyn, en positivistisk vetenskapssyn, en deduktiv forskningsansats samt en kvantitativ metod där hypotesprövning är i fokus. Undersökningen är uppbyggd utifrån ett företagsperspektiv då det är framförallt företag vi vänder oss till. Baserat på studiens teoretiska ramverk tog vi fram två hypoteser att undersöka under en femårsperiod. Studiens huvudhypotes syftar till att undersöka sambandet mellan immateriella tillgångar och skuldränta medan bihypotesen fokuserar på sambandet mellan immateriella tillgångar och företagens andel lån. Vi testade dessa hypoteser genom två olika undersökningar, först genom en totalundersökning då vi undersökte om existensen av upptagna immateriella tillgångar hade någon inverkan på responsvariablerna, och sedan genom en klusterundersökning då vi undersökte hur mängden immateriella tillgångar inverkar på responsvariablerna.

    Resultatet från studiens huvudhypotes visar att det finns ett positivt samband mellan existensen av upptagna immateriella tillgångar och skuldräntan, det innebär att om företaget har upptagna immateriella tillgångar får de betala en högre skuldränta. Detta kan bero på att immateriella tillgångar är osäkrare och därmed vill långivare ha en högre ränta som kompensation. Däremot är sambandet mellan andel upptagna immateriella tillgångar och skuldränta negativt samt har låga och varierande förklaringsgrader mellan åren. Detta kan bero på att de finansiella rapporterna har tappat i relevans och att kreditgivare lägger större vikt vid kvalitativa aspekter, vilka inte syns i balansräkning och som vår studie därmed inte fångar upp. Gällande resultaten från bihypotesen så kan vi inte uttala oss om sambandet mellan existensen av upptagna immateriella tillgångar och företagens andel lån. Däremot ser vi ett svagt och något instabilt positivt samband mellan andel upptagna immateriella tillgångar och andel lån, vilket kan bero på att företag med mycket immateriella värden har fler investeringstillfällen och därmed kräver mer extern finansiering för att kunna ta tillvara på dessa och vara konkurrenskraftiga.

    Studien är upprättad utifrån etiska aspekter samt har överlag en god reliabilitet och validitet. Förslag på vidare forskning är framförallt att genomföra studien genom en kvalitativ metod för att få en djupare förståelse för kreditgivningens kvalitativa del vilket skulle komplettera denna studie. Praktiska rekommendationer till företag är att fortsätta kämpa för sina värdefulla immateriella tillgångar för att uppnå en mer jämställd kreditgivningsprocess vilket går i linje med världens kunskapsbaserade ekonomi.

  • 474. Agostinelli, Marta
    et al.
    Cleary, Michelle
    Martin, Juan A.
    Albrectsen, Benedicte R.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Witzell, Johanna
    Pedunculate Oaks (Quercus robur L.) Differing in Vitality as Reservoirs for Fungal Biodiversity2018In: Frontiers in Microbiology, ISSN 1664-302X, E-ISSN 1664-302X, Vol. 9, article id 1758Article in journal (Refereed)
    Abstract [en]

    Ecological significance of trees growing in urban and peri-urban settings is likely to increase in future land-use regimes, calling for better understanding of their role as potential reservoirs or stepping stones for associated biodiversity. We studied the diversity of fungal endophytes in woody tissues of asymptomatic even aged pedunculate oak trees, growing as amenity trees in a peri-urban setting. The trees were classified into three groups according to their phenotypic vitality (high, medium, and low). Endophytes were cultured on potato dextrose media from surface sterilized twigs and DNA sequencing was performed to reveal the taxonomic identity of the morphotypes. In xylem tissues, the frequency and diversity of endophytes was highest in oak trees showing reduced vitality. This difference was not found for bark samples, in which the endophyte infections were more frequent and communities more diverse than in xylem. In general, most taxa were shared across the samples with few morphotypes being recovered in unique samples. Leaf phenolic profiles were found to accurately classify the trees according to their phenotypic vitality. Our results confirm that xylem is more selective substrate for endophytes than bark and that endophyte assemblages in xylem are correlated to the degree of host vitality. Thus, high vitality of trees may be associated with reduced habitat quality to wood-associated endophytes.

  • 475. Agostoni, C
    et al.
    Buonocore, G
    Carnielli, VP
    De Curtis, M
    Darmaun, D
    Decsi, T
    Domellöf, Magnus
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Embleton, ND
    Fusch, C
    Genzel-Boroviczeny, O
    Goulet, O
    Kalhan, SC
    Kolacek, S
    Koletzko, B
    Lapillonne, A
    Mihatsch, W
    Moreno, L
    Neu, J
    Poindexter, B
    Puntis, J
    Putet, G
    Rigo, J
    Riskin, A
    Salle, B
    Sauer, P
    Shamir, R
    Szajewska, H
    Thureen, P
    Turck, D
    van Goudoever, JB
    Ziegler, EE
    Enteral nutrient supply for preterm infants: commentary from the European society of paediatric gastroenterology, hepatology and nutrition committee on nutrition2010In: Journal of Pediatric Gastroenterology and Nutrition - JPGN, ISSN 0277-2116, E-ISSN 1536-4801, Vol. 50, no 1, p. 85-91Article in journal (Refereed)
    Abstract [en]

    The number of surviving children born prematurely has increased substantially during the last 2 decades. The major goal of enteral nutrient supply to these infants is to achieve growth similar to foetal growth coupled with satisfactory functional development. The accumulation of knowledge since the previous guideline on nutrition of preterm infants from the Committee on Nutrition of the European Society of Paediatric Gastroenterology and Nutrition in 1987 has made a new guideline necessary. Thus, an ad hoc expert panel was convened by the Committee on Nutrition of the European Society of Paediatric Gastroenterology, Hepatology, and Nutrition in 2007 to make appropriate recommendations. The present guideline, of which the major recommendations are summarised here (for the full report, see http://links.lww.com/A1480), is consistent with, but not identical to, recent guidelines from the Life Sciences Research Office of the American Society for Nutritional Sciences published in 2002 and recommendations from the handbook Nutrition of the Preterm Infant. Scientific Basis and Practical Guidelines, 2nd ed, edited by Tsang et al, and published in 2005. The preferred food for premature infants is fortified human milk from the infant's own mother, or, alternatively, formula designed for premature infants. This guideline aims to provide proposed advisable ranges for nutrient intakes for stable-growing preterm infants up to a weight of approximately 1800 g, because most data are available for these infants. These recommendations are based on a considered review of available scientific reports on the subject, and on expert consensus for which the available scientific data are considered inadequate.

  • 476. Agostoni, Carlo
    et al.
    Domellöf, Magnus
    Umeå University, Faculty of Medicine, Clinical Sciences, Paediatrics.
    Infant formulae: from ESPGAN recommendations towards ESPGHAN-coordinated global standards.2005In: Journal of pediatric gastroenterology and nutrition, ISSN 0277-2116, Vol. 41, no 5, p. 580-3Article in journal (Other academic)
  • 477. Agrawal, Ganesh Kumar
    et al.
    Job, Dominique
    Kieselbach, Thomas
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Barkla, Bronwyn J.
    Chen, Sixue
    Deswal, Renu
    Luethje, Sabine
    Amalraj, Ramesh Sundar
    Tanou, Georgia
    Ndimba, Bongani Kaiser
    Cramer, Rainer
    Weckwerth, Wolfram
    Wienkoop, Stefanie
    Dunn, Michael J.
    Kim, Sun Tae
    Fukao, Yochiro
    Yonekura, Masami
    Zolla, Lello
    Rohila, Jai Singh
    Waditee-Sirisattha, Rungaroon
    Masi, Antonio
    Wang, Tai
    Sarkar, Abhijit
    Agrawal, Raj
    Renaut, Jenny
    Rakwal, Randeep
    INPPO Actions and Recognition as a Driving Force for Progress in Plant Proteomics: Change of Guard, INPPO Update, and Upcoming Activities2013In: Proteomics, ISSN 1615-9853, E-ISSN 1615-9861, Vol. 13, no 21, p. 3093-3100Article in journal (Other academic)
    Abstract [en]

    The International Plant Proteomics Organization (INPPO) is a non-profit organization whose members are scientists involved or interested in plant proteomics. Since the publication of the first INPPO highlights in 2012, continued progress on many of the organization's mandates/goals has been achieved. Two major events are emphasized in this second INPPO highlights. First, the change of guard at the top, passing of the baton from Dominique Job, INPPO founding President to Ganesh Kumar Agrawal as the incoming President. Ganesh K. Agrawal, along with Dominique Job and Randeep Rakwal initiated the INPPO. Second, the most recent INPPO achievements and future targets, mainly the organization of first the INPPO World Congress in 2014, tentatively planned for Hamburg (Germany), are mentioned.

  • 478. Agrawal, Ganesh Kumar
    et al.
    Sarkar, Abhijit
    Agrawal, Raj
    Ndimba, Bongani Kaiser
    Tanou, Georgia
    Dunn, Michael J
    Kieselbach, Thomas
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Cramer, Rainer
    Wienkoop, Stefanie
    Chen, Sixue
    Rafudeen, Mohammed Suhail
    Deswal, Renu
    Barkla, Bronwyn J
    Weckwerth, Wolfram
    Heazlewood, Joshua L
    Renaut, Jenny
    Job, Dominique
    Chakraborty, Niranjan
    Rakwal, Randeep
    Boosting the Globalization of Plant Proteomics through INPPO: Current Developments and Future Prospects2012In: Proteomics, ISSN 1615-9853, E-ISSN 1615-9861, Vol. 12, no 3, p. 359-368Article in journal (Refereed)
    Abstract [en]

    The International Plant Proteomics Organization (INPPO) is a non-profit-organization consisting of people who are involved or interested in plant proteomics. INPPO is constantly growing in volume and activity, which is mostly due to the realization among plant proteomics researchers worldwide for the need of such a global platform. Their active participation resulted in the rapid growth within the first year of INPPO's official launch in 2011 via its website (www.inppo.com) and publication of the 'Viewpoint paper' in a special issue of PROTEOMICS (May 2011). Here, we will be highlighting the progress achieved in the year 2011 and the future targets for the year 2012 and onwards. INPPO has achieved a successful administrative structure, the Core Committee (CC; composed of President, Vice-President, and General Secretaries), Executive Council (EC), and General Body (GB) to achieve INPPO objectives. Various committees and subcommittees are in the process of being functionalized via discussion amongst scientists around the globe. INPPO's primary aim to popularize the plant proteomics research in biological sciences has also been recognized by PROTEOMICS where a section dedicated to plant proteomics has been introduced starting January 2012, following the very first issue of this journal devoted to plant proteomics in May 2011. To disseminate organizational activities to the scientific community, INPPO has launched a biannual (in January and July) newsletter entitled 'INPPO Express: News & Views' with the first issue published in January 2012. INPPO is also planning to have several activities in 2012, including programs within the Education Outreach committee in different countries, and the development of research ideas and proposals with priority on crop and horticultural plants, while keeping tight interactions with proteomics programs on model plants such as Arabidopsis thaliana, rice, and Medicago truncatula. Altogether, the INPPO progress and upcoming activities are because of immense support, dedication, and hard work of all members of the INPPO community, and also due to the wide encouragement and support from the communities (scientific and non-scientific).

  • 479. Agrawala, Shardul
    et al.
    Bosello, Francesco
    Carraro, Carlo
    de Bruin, Kelly
    Umeå University, Faculty of Social Sciences, Department of Economics.
    De Cian, Enrica
    Dellink, Rob
    Lanzi, Elisa
    Plan or react? Analysis of adaptation costs and benefits using integrated assessment models2011In: Climate Change Economics, ISSN 2010-0078, E-ISSN 2010-0086, Vol. 2, no 3, p. 175-208Article in journal (Refereed)
    Abstract [en]

    This report examines adaptation and mitigation within an integrated framework. Global and regional costs of adaptation are assessed dynamically and the resulting benefits are quantified. This is accomplished by developing a framework to incorporate adaptation as a policy variable within three Integrated Assessment Models (IAMs); the global Dynamic Integrated model of Climate and the Economy (DICE), the Regional Integrated model of Climate and the Economy (RICE), and the World Induced Technical Change Hybrid (WITCH) model. The framework developed here takes into account investments in reactive adaptation and in adaptation "stocks", as well as investments in building adaptive capacity. This report presents the first inter-model comparison of results on adaptation costs using the emerging category of adaptation-IAMs. Results show that least-cost policy response to climate change will need to involve subsantial amounts of mitigation efforts, investments in adaptation stock, reactive adaptation measures and adaptive capacity to limit the remaining damages.

  • 480.
    Agrell, Daniel
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Optimerad design och tillverkningsmetod av koncentrerande solfångare2015Independent thesis Advanced level (degree of Master (Two Years)), 300 HE creditsStudent thesis
    Abstract [en]

    The sun is our most important source of energy for us to be able to cope with the evermore pressuring climate threats. This has always been very clear for Absolicon Solar Collector AB in Härnösand, developers of concentrating solar collectors. The company has so far produced solar collectors which can produce both thermal and electrical power for mid-sized installations such as hotels and hospital. Now however, they are changing direction. Absolicon wants to address the many bigger industries with a demand for steam, in countries rich with solar radiation. Absolicon also wants to develop a production line for production of their solar collector, for deployment in the countries where the demand is the biggest.

     

    In a project partially financed by the Swedish energy department, a demonstrational production line will be built in Härnösand. The production line will be used to build a demonstrational field at HEMAB (Härnösands Energi och Miljö AB) with a new generation of solar collectors, optimized for steam production. The solar collectors built today has a problem with the reflector not getting an optimized shape throughout the whole collector. This has to be rectified since the demand on the shape of the reflector is higher on the new generation of solar collectors. This Is due to the use of a smaller receiver. Furthermore a mounting carriage using a new production method is to be developed for the production line. The mounting carriage should, by using vacuum, form and fixate the reflector of the collector while it also optimizes its shape.

     

    Tests was performed to examine how to optimize the shape of the reflector. A test rig was used to examine how a thin sheet of metal can be formed and fixated using vacuum while developing an optimized production method. A prototype carriage for production of 2 m long collectors using the new method was designed and constructed for evaluation.

     

    The results of the evaluation showed that the developed method is working well and that a receiver diameter of 19 mm can be used. The method is based on letting the edges of the reflector sheet hang free, which eliminates unwanted tensions in the reflector.

     

    The prototype which was built is ready for upscaling to a 6 m mounting carriage which will be able to produce the new generation of solar collectors for the demonstration field. A mounting process for production of solar collectors in a production line has been proposed which can shorten the mounting time and work load to less than 45 minutes and 1-2 persons per collector.

    The full text will be freely available from 2025-09-01 20:46
  • 481.
    Agrell, Elias
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Analys av massapumps- och mixerarbete vid Metsä Board Sverige AB, Husums Fabriker: Energibesparingsåtgärder vid blekeri 4 & 5 med jämförelse mot ny utrustning2014Independent thesis Basic level (university diploma), 180 HE creditsStudent thesis
    Abstract [en]

    Husums plant has a selection of different pulp pumps at bleaching plant 4 and 5. The displacement- (HC-pump, Sund Defibrator PTD-60) and centrifugalpumps (MC-pump, MCA 42-200, MCP 30/20) are of interest in this report. The centrifugal pumps are controlled by throttle valves, which result in an energy loss. Chemical mixers are used to mix ClO2 into the pulp before proceeding into a holding tower where the bleaching process occurs.

    The energy demand of the different positions has been measured or calculated to be used in comparisons against new equipment. Quotations were requested and delivered from Valmet and Sulzer. The quotations were made with a production increase of 10 ADMt/h and plant compared to current equipment. Therefore energy need of the equipment in the quotation had to be recalculated to the same production output as when measurements were conducted to be comparable. Quotation of the pumps assumes the use of frequency inverters.

    A deeper investigation was made for 441PU255 which is located at bleaching plant 4. The drop leg level of the pump is controlled via a throttle valve. A frequency inverter is installed but not utilized to maintain constant pulp level in the drop leg. This was due to physical changes in the process not being compensated for in the control system. This caused the drop leg level to oscillate when automatic control was used. As a workaround the drive had been set at a constant speed. To investigate the potential savings, an attempt was made in which the speed was lowered from 1520 rpm to 1100 rpm, resulting in a power reduction of 82 kW or 342,081 Sek per year at a production of 36 ADMT/h. The experiment was done with slightly lower production output than desirable; because of this, savings will decrease slightly at higher outputs.

    Comparisons showed that considerable amounts of energy could be saved at all positions. However the investment cost is high and therefore favorable payback times can only be seen for some of the positions. The MC-pumps are oversized and in need of constant throttling therefore the majority of the energy savings is made through the installation of frequency inverters and not the pump upgrade.

  • 482.
    Agrell, Johanna
    Umeå University, Faculty of Social Sciences, Department of Education.
    Åtgärdsprogram - en klyfta mellan ideologi och praktik?: En studie om hur lärare och rektorer i en kommun förstår direktiv rörande åtgärdsprogram2012Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 483. Agren, Per-Henrik
    et al.
    Tullberg, Tycho
    Mukka, Sebastian
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Wretenberg, Per
    Sayed-Noor, Arkan S.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Post-traumatic in situ fusion after calcaneal fractures: A retrospective study with 7-28 years follow-up2015In: Foot and Ankle Surgery, ISSN 1268-7731, E-ISSN 1460-9584, Vol. 21, no 1, p. 56-59Article in journal (Refereed)
    Abstract [en]

    Background: In situ fusion as salvage operation after calcaneal fractures has been used. In this retrospective investigation, a group of in situ fused patients is analyzed with long-term follow-up.

    Methods: Twenty-nine patients with in situ single or multiple fusions performed between 1970 and 1990 were included. In 1998 these patients were examined with plain radiographs and computerized tomography (CT) scan of the affected foot. Also, a visual analogue score (VAS) for calcaneal fractures, short form health survey (SF-36), Olerud Molander score and American Orthopaedic Foot and Ankle society (AOFAS) hindfoot score were evaluated.

    Results: The plain radiographs and CT scan showed severe remaining deformities in these patients. The outcome parameters were generally poor and correlated to the degree of remaining deformity.

    Conclusions: Simple in situ fusion, without consideration of the deformity at hand, after a calcaneal fracture is not an adequate treatment and generally associated with poor outcome. (C) 2014 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

  • 484. Agreus, Lars
    et al.
    Hellström, Per M.
    Talley, Nicholas J.
    Wallner, Bengt
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Forsberg, Anna
    Vieth, Michael
    Veits, Lothar
    Björkegren, Karin
    Engstrand, Lars
    Andreasson, Anna
    Towards a healthy stomach? Helicobacter pylori prevalence has dramatically decreased over 23 years in adults in a Swedish community2016In: United European Gastroenterology journal, ISSN 2050-6406, E-ISSN 2050-6414, Vol. 4, no 5, p. 686-696Article in journal (Refereed)
    Abstract [en]

    Background In Western countries the prevalence of Helicobacter pylori (H. pylori) infection may be declining but there is a lack of recent longitudinal population studies. We evaluated the changing epidemiology over a 23-year period in Sweden. Materials and methods In 1989, the validated Abdominal Symptom Questionnaire (ASQ) was mailed to a random sample of inhabitants (ages 22-80 years) in a Swedish community, and 1097 (87%) responded. H. pylori serology was analysed in a representative subsample (n=145). Twenty-three years later, the ASQ was mailed again using similar selection criteria, and 388 out of 1036 responders had an upper endoscopy with assessment of H. pylori and corpus atrophy status. Results The prevalence of positive H. pylori serology decreased from 37.9% (1989) to 15.8% (2012), corresponding to a decrease in odds of 75% per decade (odds ratio (OR): 0.25; 95% confidence interval (CI): 0.11-0.59, p=0.001) independent of age, gender, body mass index (BMI) and level of education, with a pattern consistent with a birth cohort effect. The prevalence increased with increasing age (p=0.001). The prevalence of H. pylori on histology in 2012 was 11.4% (95% CI 8.6-15.0). The prevalence of corpus atrophy on serology and/or histology in 2012 was 3.2% (95% CI 1.8-5.5); all cases were 57 years old. Conclusion The stomach is healthier in 2012 compared with 1989. H. pylori prevalence in adults has decreased over the last two decades to a level where clinical management might be affected.

  • 485.
    Agritellis, Ioannis
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Social media as the Cosmo Neighborhood2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The world has been transformed through the internet into a "global village",and social media platforms have possibly transformed the world into a larger neighborhood covering many regions of the world. Social networks such as Facebook and Twitter came into people’s lives through the Internet, growing daily at a large rate, and it has been proven that they are very popular. This study examines links between different phenomena through social media platforms (e.g. Facebook, Twitter, blogs, etc.). It is discusses cohesiveness, desire to belong, sense of community, beliefs and opinions about different forms of these phenomena in popular virtual platforms in correlation with trust in social media, criticism of information that is spread by these virtual platforms, and if people are influenced in consumer decision making. A questionnaire has been distributed to a convenient sample of 159 international and Swedish students in Sweden in October-November 2012 in both English and Swedish versions. According to the peoples’ answers, tendencies were observed such as to not trust the platforms, and also the information received, beliefs such that social media are "controlled", negative critique, but also an expression for a need for ‘membership’.

  • 486.
    Agronius, Sofia
    et al.
    Umeå University, Faculty of Arts, Department of Creative Studies.
    Sjöberg, Eva
    Umeå University, Faculty of Arts, Department of Creative Studies.
    Hur elever upplever betyg och bedömning i bild- och medieämnen: - en kvalitativ studie2008Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Betygen är en självklar och ofrånkomlig del i skolans vardag och diskussioner förs hela tiden kring dess utformning, genomförande och betydelse i samhällsdebatten. Ofta är det politikers åsikter man får höra när det gäller betyg och bedömning. Men de som påverkas mest av betygen, eleverna som går i skolan just nu, hur tänker de? Syftet med undersökningen är att genom kvalitativa intervjuer ta reda på hur gymnasieelever upplever betyg och bedömning i bild- och medieämnen. Vi kan se att det finns en uppdelning i elevernas svar. Å ena sidan finns den individuella upplevelsen å andra sidan den upplevelse som knyts till kontexten – skola, lärare, kamrater och framtid. En elev kan ha både positiva och negativa erfarenheter och därigenom ha ett brett spektra av upplevelser. Det visar på en komplexitet i upplevelsen av att bli bedömd och betygsatt.

    Detta är en del av ett så kallat alternativt examensarbete där den första delen är denna uppsats och den andra består av en tidning som utformats som diskussionsunderlag för skolan i ämnet.

    Tidningen finns i digital form på http://www.estet.umu.se/alt.exarb/ men även som bilaga i detta arbete.

  • 487. Agudo, Antonio
    et al.
    Bonet, Catalina
    Sala, Núria
    Muñoz, Xavier
    Aranda, Núria
    Fonseca-Nunes, Ana
    Clavel-Chapelon, Françoise
    Boutron-Ruault, Marie Christine
    Vineis, Paolo
    Panico, Salvatore
    Palli, Domenico
    Tumino, Rosario
    Grioni, Sara
    Quirós, J Ramón
    Molina, Esther
    Navarro, Carmen
    Barricarte, Aurelio
    Chamosa, Saioa
    Allen, Naomi E
    Khaw, Kay-Tee
    Bueno-de-Mesquita, H Bas
    Siersema, Peter D
    Numans, Mattijs E
    Trichopoulou, Antonia
    Lagiou, Pagona
    Trichopoulos, Dimitrios
    Kaaks, Rudof
    Canzian, Federico
    Boeing, Heiner
    Meidtner, Karina
    Johansson, Mattias
    Umeå University, Faculty of Medicine. WHO, IARC, Lyon, France.
    Sund, Malin
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Manjer, Jonas
    Overvad, Kim
    Tjonneland, Anne
    Lund, Eiliv
    Weiderpass, Elisabete
    Jenab, Mazda
    Fedirko, Veronika
    Offerhaus, G Johan A
    Riboli, Elio
    González, Carlos A
    Jakszyn, Paula
    Hemochromatosis (HFE) gene mutations and risk of gastric cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC) study2013In: Carcinogenesis, ISSN 0143-3334, E-ISSN 1460-2180, Vol. 34, no 6, p. 1244-1250Article in journal (Refereed)
    Abstract [en]

    Hereditary hemochromatosis (HH) is a strong risk factor for hepatocellular cancer, and mutations in the HFE gene associated with HH and iron overload may be related to other tumors, but no studies have been reported for gastric cancer (GC). A nested case-control study was conducted within the European Prospective Investigation into Cancer and Nutrition (EPIC), including 365 incident gastric adenocarcinoma and 1284 controls matched by center, sex, age and date of blood collection. Genotype analysis was performed for two functional polymorphisms (C282Y/rs1800562 and H63D/rs1799945) and seven tagSNPs of the HFE genomic region. Association with all gastric adenocarcinoma, and according to anatomical localization and histological subtype, was assessed by means of the odds ratio (OR) and 95% confidence interval (CI) estimated by unconditional logistic regression adjusted for the matching variables. We observed a significant association for H63D with OR (per rare allele) of 1.32 (CI = 1.03-1.69). In subgroup analyses, the association was stronger for non-cardia anatomical subsite (OR = 1.60, CI = 1.16-2.21) and intestinal histological subtype (OR = 1.82, CI = 1.27-2.62). Among intestinal cases, two tagSNPs (rs1572982 and rs6918586) also showed a significant association that disappeared after adjustment for H63D. No association with tumors located in the cardia or with diffuse subtype was found for any of the nine SNPs analyzed. Our results suggest that H63D variant in HFE gene seems to be associated with GC risk of the non-cardia region and intestinal type, possibly due to its association with iron overload although a role for other mechanisms cannot be entirely ruled out.

  • 488. Agudo, Antonio
    et al.
    Bonet, Catalina
    Travier, Noemie
    Gonzalez, Carlos A.
    Vineis, Paolo
    Bueno-de-Mesquita, H. Bas
    Trichopoulos, Dimitrios
    Boffetta, Paolo
    Clavel-Chapelon, Francoise
    Boutron-Ruault, Marie-Christine
    Kaaks, Rudolf
    Lukanova, Annekatrin
    Schuetze, Madlen
    Boeing, Heiner
    Tjonneland, Anne
    Halkjaer, Jytte
    Overvad, Kim
    Dahm, Christina C.
    Ramon Quiros, J.
    Sanchez, Maria-Jose
    Larranaga, Nerea
    Navarro, Carmen
    Ardanaz, Eva
    Khaw, Kay-Tee
    Wareham, Nicholas J.
    Key, Timothy J.
    Allen, Naomi E.
    Trichopoulou, Antonia
    Lagiou, Pagona
    Palli, Domenico
    Sieri, Sabina
    Tumino, Rosario
    Panico, Salvatore
    Boshuizen, Hendriek
    Buchner, Frederike L.
    Peeters, Petra H. M.
    Borgquist, Signe
    Almquist, Martin
    Hallmans, Göran
    Umeå University, Faculty of Medicine, Department of Biobank Research.
    Johansson, Ingegerd
    Umeå University, Faculty of Medicine, Department of Odontology, School of Dentistry.
    Gram, Inger T.
    Lund, Eiliv
    Weiderpass, Elisabete
    Romieu, Isabelle
    Riboli, Elio
    Impact of Cigarette Smoking on Cancer Risk in the European Prospective Investigation into Cancer and Nutrition Study2012In: Journal of Clinical Oncology, ISSN 0732-183X, E-ISSN 1527-7755, Vol. 30, no 36, p. 4550-4557Article in journal (Refereed)
    Abstract [en]

    Purpose Our aim was to assess the impact of cigarette smoking on the risk of the tumors classified by the International Agency for Research on Cancer as causally associated with smoking, referred to as tobacco-related cancers (TRC). Methods The study population included 441,211 participants (133,018 men and 308,193 women) from the European Prospective Investigation Into Cancer and Nutrition. We investigated 14,563 participants who developed a TRC during an average follow-up of 11 years. The impact of smoking cigarettes on cancer risk was assessed by the population attributable fraction (AF(p)), calculated using the adjusted hazard ratios and 95% CI for current and former smokers, plus either the prevalence of smoking among cancer cases or estimates from surveys in representative samples of the population in each country. Results The proportion of all TRC attributable to cigarette smoking was 34.9% (95% CI, 32.5 to 37.4) using the smoking prevalence among cases and 36.2% (95% CI, 33.7 to 38.6) using the smoking prevalence from the population. The AF(p) were above 80% for cancers of the lung and larynx, between 20% and 50% for most respiratory and digestive cancers and tumors from the lower urinary tract, and below 20% for the remaining TRC. Conclusion Using data on cancer incidence for 2008 and our AF(p) estimates, about 270,000 new cancer diagnoses per year can be considered attributable to cigarette smoking in the eight European countries with available data for both men and women (Italy, Spain, United Kingdom, the Netherlands, Greece, Germany, Sweden, Denmark). 

  • 489. Agudo, Antonio
    et al.
    Cayssials, Valerie
    Bonet, Catalina
    Tjønneland, Anne
    Overvad, Kim
    Boutron-Ruault, Marie-Christine
    Affret, Aurélie
    Fagherazzi, Guy
    Katzke, Verena
    Schübel, Ruth
    Trichopoulou, Antonia
    Karakatsani, Anna
    La Vecchia, Carlo
    Palli, Domenico
    Grioni, Sara
    Tumino, Rosario
    Ricceri, Fulvio
    Panico, Salvatore
    Bueno-de-Mesquita, Bas
    Peeters, Petra H.
    Weiderpass, Elisabete
    Skeie, Guri
    Nøst, Theresa H.
    Lasheras, Cristina
    Rodríguez-Barranco, Miguel
    Amiano, Pilar
    Chirlaque, María-Dolores
    Ardanaz, Eva
    Ohlsson, Bodil
    Dias, Joana A.
    Nilsson, Lena M.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Nutritional Research. Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Myte, Robin
    Khaw, Kay-Tee
    Perez-Cornago, Aurora
    Gunter, Marc
    Huybrechts, Inge
    Cross, Amanda J.
    Tsilidis, Kostas
    Riboli, Elio
    Jakszyn, Paula
    Inflammatory potential of the diet and risk of gastric cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC) study2018In: American Journal of Clinical Nutrition, ISSN 0002-9165, E-ISSN 1938-3207, Vol. 107, no 4, p. 607-616Article in journal (Refereed)
    Abstract [en]

    Chronic inflammation plays a critical role in the pathogenesis of the 2 major types of gastric cancer. Several foods, nutrients, and nonnutrient food components seem to be involved in the regulation of chronic inflammation. We assessed the association between the inflammatory potential of the diet and the risk of gastric carcinoma, overall and for the 2 major subsites: cardia cancers and noncardia cancers. A total of 476,160 subjects (30% men, 70% women) from the European Investigation into Cancer and Nutrition (EPIC) study were followed for 14 y, during which 913 incident cases of gastric carcinoma were identified, including 236 located in the cardia, 341 in the distal part of the stomach (noncardia), and 336 with overlapping or unknown tumor site. The dietary inflammatory potential was assessed by means of an inflammatory score of the diet (ISD), calculated with the use of 28 dietary components and their corresponding inflammatory scores. The association between the ISD and gastric cancer risk was estimated by HRs and 95% CIs calculated by multivariate Cox regression models adjusted for confounders. The inflammatory potential of the diet was associated with an increased risk of gastric cancer. The HR (95% CI) for each increase in 1 SD of the ISD were 1.25 (1.12, 1.39) for all gastric cancers, 1.30 (1.06, 1.59) for cardia cancers, and 1.07 (0.89, 1.28) for noncardia cancers. The corresponding values for the highest compared with the lowest quartiles of the ISD were 1.66 (1.26, 2.20), 1.94 (1.14, 3.30), and 1.07 (0.70, 1.70), respectively. Our results suggest that low-grade chronic inflammation induced by the diet may be associated with gastric cancer risk. This pattern seems to be more consistent for gastric carcinomas located in the cardia than for those located in the distal stomach. This study is listed on the ISRCTN registry as ISRCTN12136108.

  • 490. Agudo, Antonio
    et al.
    Sala, Naría
    Pera, Guillem
    Capella, Gabriel
    Berenguer, Antonio
    García, Nadia
    Palli, Domenico
    Boeing, Heiner
    Del Giudice, Giuseppe
    Saieva, Calogero
    Carneiro, Fatima
    Berrino, Franco
    Sacerdote, Carlotta
    Tumino, Rosario
    Panico, Salvatore
    Berglund, Göran
    Siman, Henrik
    Stenling, Roger
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology. Patologi.
    Hallmans, Göran
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Nutritional Research.
    Martínez, Carmen
    Bilbao, Roberto
    Barricarte, Aurelio
    Navarro, Carmen
    Quiros, José
    Allen, Naomi
    Key, Tim
    Bingham, Sheila
    Khaw, Kay-Tee
    Linseisen, Jakob
    Nagel, Gabriele
    Overvad, Kim
    Tjonneland, Anne
    Olsen, Anja
    Bueno-de-Mesquita, H Bas
    Boshuizen, Hendriek C
    Peeters, Petra H
    Numans, Mattijs E
    Clavel-Chapelon, Francoíse
    Boutron-Ruault, Marie-Christine
    Trichopoulou, Antonia
    Lund, Eiliv
    Offerhaus, Johan
    Jenab, Mazda
    Ferrari, Pietro
    Norat, Teresa
    Riboli, Elio
    González, Carlos A
    Polymorphisms in metabolic genes related to tobacco smoke and the risk of gastric cancer in the European prospective investigation into cancer and nutrition.2006In: Cancer Epidemiology Biomarkers & Prevention, ISSN 1055-9965, Vol. 15, no 12, p. 2427-34Article in journal (Refereed)
  • 491. Agudo, Antonio
    et al.
    Sala, Nária
    Pera, Guillem
    Capella, Gabriel
    Berenguer, Antonio
    García, Nadia
    Palli, Domenico
    Boeing, Heiner
    Del Giudice, Giuseppe
    Saieva, Calogero
    Carneiro, Fatima
    Berrino, Franco
    Sacerdote, Carlotta
    Tumino, Rosario
    Panico, Salvatore
    Berglund, Göran
    Siman, Henrik
    Stenling, Roger
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology. Patologi.
    Hallmans, Göran
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Nutritional Research.
    Martínez, Carmen
    Amiano, Pilar
    Barricarte, Aurelio
    Navarro, Carmen
    Qui, Jose R
    Allen, Naomi
    Key, Tim
    Bingham, Sheila
    Khaw, Kay-Tee
    Linseisen, Jakob
    Nagel, Gabriele
    Overvad, Kim
    Tjonneland, Anne
    Olsen, Anja
    Bueno-de-Mesquita, H Bas
    Boshuizen, Hendriek C
    Peeters, Petra H
    Numans, Mattijs E
    Clavel-Chapelon, Francoíse
    Boutron-Ruault, Marie-Christine
    Trichopoulou, Antonia
    Lund, Eiliv
    Báker, Hendrik
    Jenab, Mazda
    Ferrari, Pietro
    Norat, Teresa
    Riboli, Elio
    González, Carlos A
    No association between polymorphisms in CYP2E1, GSTM1, NAT1, NAT2 and the risk of gastric adenocarcinoma in the European prospective investigation into cancer and nutrition.2006In: Cancer Epidemiology Biomarkers & Prevention, ISSN 1055-9965, Vol. 15, no 5, p. 1043-5Article in journal (Refereed)
  • 492. Agugiaro, G.
    et al.
    Remondino, F.
    Girardi, G.
    von Schwerin, J.
    Richards-Rissetto, Heather
    Umeå University, Faculty of Arts, Humlab.
    De Amicis, R.
    A web-based interactive tool for multi-resolution 3d models of a maya archaeological site2011In: 4TH ISPRS INTERNATIONAL WORKSHOP 3D-ARCH 2011: 3D VIRTUAL RECONSTRUCTION AND VISUALIZATION OF COMPLEX ARCHITECTURES / [ed] Remondino, F; ElHakim, S, 2011, no W16, p. 23-30Conference paper (Refereed)
    Abstract [en]

    Continuous technological advances in surveying, computing and digital-content delivery are strongly contributing to a change in the way Cultural Heritage is "perceived": new tools and methodologies for documentation, reconstruction and research are being created to assist not only scholars, but also to reach more potential users (e.g. students and tourists) willing to access more detailed information about art history and archaeology. 3D computer-simulated models, sometimes set in virtual landscapes, offer for example the chance to explore possible hypothetical reconstructions, while on-line GIS resources can help interactive analyses of relationships and change over space and time. While for some research purposes a traditional 2D approach may suffice, this is not the case for more complex analyses concerning spatial and temporal features of architecture, like for example the relationship of architecture and landscape, visibility studies etc. The project aims therefore at creating a tool, called "QueryArch3D" tool, which enables the web-based visualisation and queries of an interactive, multi-resolution 3D model in the framework of Cultural Heritage. More specifically, a complete Maya archaeological site, located in Copan (Honduras), has been chosen as case study to test and demonstrate the platform's capabilities. Much of the site has been surveyed and modelled at different levels of detail (LoD) and the geometric model has been semantically segmented and integrated with attribute data gathered from several external data sources. The paper describes the characteristics of the research work, along with its implementation issues and the initial results of the developed prototype. [GRAPHICS] .

  • 493. Aguiar, Francisca C.
    et al.
    Segurado, Pedro
    Martins, Maria Joao
    Bejarano, Maria Dolores
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Nilsson, Christer
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Portela, Maria Manuela
    Merritt, David M.
    The abundance and distribution of guilds of riparian woody plants change in response to land use and flow regulation2018In: Journal of Applied Ecology, ISSN 0021-8901, E-ISSN 1365-2664, Vol. 55, no 5, p. 2227-2240Article in journal (Refereed)
    Abstract [en]

    1. Many riparian ecosystems in Mediterranean Europe are affected by land use and flow alteration by dams. We focused on understanding how these stressors and their components affect riparian forests in the region. We asked the following questions: (1) Are there well‐defined, responsive riparian guilds? (2) Do dam‐induced streamflows determine abundance and distribution of riparian guilds? (3) What are the main drivers governing composition and cover of riparian guilds in regulated rivers?

    2. We inventoried the cover of riparian woody species in free‐flowing rivers and downstream of dams. We performed a cluster analysis and ordination to derive riparian guilds, using abundance data from 66 riparian woody species and 26 functional plant traits. We used a reduced set of principal components for the environment, land use and hydrology, and general linear modelling to explore the effect of these factors (separately and combined) on riparian guilds.

    3. We found that: (1) four dominant guilds are responsive to disturbance in southwestern European streams, namely the obligate riparian, water‐stress tolerant, deciduous competitive and Mediterranean evergreen guilds; (2) a set of land use and hydrological variables differentially affect the diverse co‐occurring riparian guilds; (3) frequency and duration of high flow pulses and the low‐flow conditions were major drivers of change in landscapes dominated by intensive agriculture and forestry; (4) storage reservoirs reduced the cover of obligate riparian and Mediterranean evergreen guilds, and increased the abundance of water‐stress tolerant and deciduous competitive guilds, while run‐of‐river dams, having limited water storage, reduced both obligate and deciduous competitive guilds.

    4. Synthesis and applications. Future research in southwestern Europe should address the resilience of riparian guilds and the effects of interacting landscape factors and stressors on guild distribution. Streamflow regulations downstream of reservoirs should focus on specific flow components, namely the magnitude of flows, and frequency and duration of extreme flow events. For successful mitigation of the dam‐induced effects on riparian vegetation, river management plans must incorporate the environmental and land use site‐specific contexts.

  • 494.
    Aguilar, Luis T.
    et al.
    Instituto Politecnico Nacional.
    Boiko, Igor
    University of Calgary.
    Fridman, Leonid
    Universidad Nacional Autonoma de Mexico (UNAM),.
    Freidovich, Leonid
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Inducing oscillations in an Inertia wheel pendulum via Two-relays controller: theory and experiments2009In: American control conference, 2009. ACC 09, Piscataway, NJ: IEEE, Institute of Electrical and Electronics Engineers , 2009, p. 65-70Conference paper (Refereed)
    Abstract [en]

    A tool for generating a self-excited oscillations for an inertia wheel pendulum by means of a variable structure controller is proposed. The original system is transformed into the normal form for exact linearization. The design procedure, based on Describing Function (DF) method, allows for finding the explicit expressions of the two-relays controller gain parameters in terms of the desired frequency and amplitude. Necessary condition for orbital asymptotic stability of the output of the exactly linearized system is derived. Performance issues of the system with self-excited oscillations are validated with experiments.

  • 495. Aguilar, Luis T.
    et al.
    Boiko, Igor M.
    Fridman, Leonid M.
    Freidovich, Leonid B.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Generating oscillations in inertia wheel pendulum via two-relay controller2012In: International Journal of Robust and Nonlinear Control, ISSN 1049-8923, E-ISSN 1099-1239, Vol. 22, no 3, p. 318-330Article in journal (Refereed)
    Abstract [en]

    The problem of generating oscillations of the inertia wheel pendulum is considered. We combine exact feedback linearization with two-relay controller, tuned using frequency-domain tools, such as computing the locus of a perturbed relay system. Explicit expressions for the parameters of the controller in terms of the desired frequency and amplitude are derived. Sufficient conditions for orbital asymptotic stability of the closed-loop system are obtained with the help of the Poincare map. Performance is validated via experiments. The approach can be easily applied for a minimum phase system, provided the behavior of the states of the zero dynamics is of no concern. Copyright (C) 2011 John Wiley & Sons, Ltd.

  • 496.
    Aguilar, Luis T.
    et al.
    CITEDI, National Polytechnic Institute, Tijuana, BC, Mexico.
    Freidovich, Leonid
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Orlov, Yury
    CICESE Research Center, Ensenada, Baja California, Mexico.
    Merida, Jovan
    CITEDI, National Polytechnic Institute, Tijuana, BC, Mexico.
    Performance Analysis of Relay Feedback Position Regulators for Manipulators with Coulomb Friction2013In: Proc. 12th European Control Conference, NEW YORK, NY 10017 USA: IEEE , 2013, p. 3754-3759Conference paper (Refereed)
    Abstract [en]

    The purpose of the paper is to analyze the performance of several global position regulators for robot manipulators with Coulomb friction. All the controllers include a proportional-differential part and a switched part whereas the difference between the controllers is in the way of compensation of the gravitational forces. Stability analysis is also revisited within the nonsmooth Lyapunov function framework for the controllers with and without gravity pre-compensation. Performance issues of the proposed controllers are evaluated in an experimental study of a five degrees-of-freedom robot manipulator. In the experiments, we choose two criteria for performance analysis. In the first set of experiments, we set the same gains to all the controllers. In the second set of experiments, the gains of the controller were chosen such that the work done by the manipulator is similar.

  • 497.
    Aguilar, Ximena
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Folding and interaction studies of subunits in protein complexes2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Proteins function as worker molecules in the cell and their natural environment is crowded. How they fold in a cell-like environment and how they recognize their interacting partners in such conditions, are questions that underlie the work of this thesis.

    Two distinct subjects were investigated using a combination of biochemical- and biophysical methods. First, the unfolding/dissociation of a heptameric protein (cpn10) in the presence of the crowding agent Ficoll 70. Ficoll 70 was used to mimic the crowded environment in the cell and it has been used previously to study macromolecular crowding effects, or excluded volume effects, in protein folding studies. Second, the conformational changes upon interaction between the Mediator subunit Med25 and the transcription factor Dreb2a from Arabidopsis thaliana. Mediator is a transcriptional co-regulator complex which is conserved from yeast to humans. The molecular mechanisms of its action are however not entirely understood. It has been proposed that the Mediator complex conveys regulatory signals from promoter-bound transcription factors (activators/repressors) to the RNA polymerase II machinery through conformational rearrangements.

    The results from the folding study showed that cpn10 was stabilized in the presence of Ficoll 70 during thermal- and chemical induced unfolding (GuHCl). The thermal transition midpoint increased by 4°C, and the chemical midpoint by 0.5 M GuHCl as compared to buffer conditions. Also the heptamer-monomer dissociation was affected in the presence of Ficoll 70, the transition midpoint was lower in Ficoll 70 (3.1 μM) compared to in buffer (8.1 μM) thus indicating tighter binding in crowded conditions. The coupled unfolding/dissociation free energy for the heptamer increased by about 36 kJ/mol in Ficoll. Altogether, the results revealed that the stability effect on cpn10 due to macromolecular crowding was larger in the individual monomers (33%) than at the monomer-monomer interfaces (8%).

    The results from the interaction study indicated conformational changes upon interaction between the A. thaliana Med25 ACtivator Interaction Domain (ACID) and Dreb2a. Structural changes were probed to originate from unstructured Dreb2a and not from the Med25-ACID. Human Med25-ACID was also found to interact with the plant-specific Dreb2a, even though the ACIDs from human and A. thaliana share low sequence homology. Moreover, the human Med25-interacting transcription factor VP16 was found to interact with A. thaliana Med25. Finally, NMR, ITC and pull-down experiments showed that the unrelated transcription factors Dreb2a and

    VP16 interact with overlapping regions in the ACIDs of A. thaliana and human Med25.

    The results presented in this thesis contribute to previous reports in two different aspects. Firstly, they lend support to the findings that the intracellular environment affects the biophysical properties of proteins. It will therefore be important to continue comparing results between in vitro and cell-like conditions to measure the magnitude of such effects and to improve the understanding of protein folding and thereby misfolding of proteins in cells. Better knowledge of protein misfolding mechanisms is critical since they are associated to several neurodegenerative diseases such as Alzheimer’s and Parkinson's. Secondly, our results substantiate the notion that transcription factors are able to bind multiple targets and that they gain structure upon binding. They also show that subunits of the conserved Mediator complex, despite low sequence homologies, retain a conserved structure and function when comparing evolutionary diverged species.

  • 498.
    Aguilar, Ximena
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Blomberg, Jeanette
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Brännström, Kristoffer
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Olofsson, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Schleucher, Jurgen
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Björklund, Stefan
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Interaction Studies of the Human and Arabidopsis thaliana Med25-ACID Proteins with the Herpes Simplex Virus VP16-and Plant-Specific Dreb2a Transcription Factors2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 5, p. e98575-Article in journal (Refereed)
    Abstract [en]

    Mediator is an evolutionary conserved multi-protein complex present in all eukaryotes. It functions as a transcriptional coregulator by conveying signals from activators and repressors to the RNA polymerase II transcription machinery. The Arabidopsis thaliana Med25 (aMed25) ACtivation Interaction Domain (ACID) interacts with the Dreb2a activator which is involved in plant stress response pathways, while Human Med25-ACID (hMed25) interacts with the herpes simplex virus VP16 activator. Despite low sequence similarity, hMed25-ACID also interacts with the plant-specific Dreb2a transcriptional activator protein. We have used GST pull-down-, surface plasmon resonance-, isothermal titration calorimetry and NMR chemical shift experiments to characterize interactions between Dreb2a and VP16, with the hMed25 and aMed25-ACIDs. We found that VP16 interacts with aMed25-ACID with similar affinity as with hMed25-ACID and that the binding surface on aMed25-ACID overlaps with the binding site for Dreb2a. We also show that the Dreb2a interaction region in hMed25-ACID overlaps with the earlier reported VP16 binding site. In addition, we show that hMed25-ACID/Dreb2a and aMed25-ACID/Dreb2a display similar binding affinities but different binding energetics. Our results therefore indicate that interaction between transcriptional regulators and their target proteins in Mediator are less dependent on the primary sequences in the interaction domains but that these domains fold into similar structures upon interaction.

  • 499.
    Aguilar, Ximena
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Weise, Christoph
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sparrman, Tobias
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Wolf-Watz, Magnus
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Wittung-Stafshede, Pernilla
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Macromolecular crowding extended to a heptameric system: the co-chaperonin protein 102011In: Biochemistry, ISSN 0006-2960, E-ISSN 1520-4995, Vol. 50, no 14, p. 3034-3044Article in journal (Refereed)
    Abstract [en]

    Experiments on monomeric proteins have shown that macromolecular crowding can stabilize toward heat perturbation and also modulate native-state structure. To assess the effects of macromolecular crowding on unfolding of an oligomeric protein, we here tested the effects of the synthetic crowding agent Ficoll 70 on human cpn10 (GroES in E. coli), a heptameric protein consisting of seven identical β-barrel subunits assembling into a ring. Using far-UV circular dichroism (CD), tyrosine fluorescence, nuclear magnetic resonance (NMR), and cross-linking experiments, we investigated thermal and chemical stability, as well as the heptamer-monomer dissociation constant, without and with crowding agent. We find that crowding shifts the heptamer-monomer equilibrium constant in the direction of the heptamer. The cpn10 heptamer is both thermally and thermodynamically stabilized in 300 mg/mL Ficoll 70 as compared to regular buffer conditions. Kinetic unfolding experiments show that the increased stability in crowded conditions, in part, is explained by slower unfolding rates. A thermodynamic cycle reveals that in presence of 300 mg/mL Ficoll the thermodynamic stability of each cpn10 monomer increases by over 30%, whereas the interfaces are stabilized by less than 10%. We also introduce a new approach to analyze the spectroscopic data that makes use of multiple wavelengths: this provides robust error estimates of thermodynamic parameters.

  • 500. Aguilera, Adriana Freites
    et al.
    Tolvanen, Pasi
    Heredia, Shuyana
    Muñoz, Marta González
    Samson, Tina
    Oger, Adrien
    Verove, Antoine
    Eränen, Kari
    Leveneur, Sebastien
    Mikkola, Jyri-Pekka
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Industrial Chemistry & Reaction Engineering, Department of Chemical Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Åbo-Turku, Finland.
    Salmi, Tapio
    Epoxidation of fatty acids and vegetable oils assisted by microwaves catalyzed by a cation exchange resin2018In: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 57, no 11, p. 3876-3886Article in journal (Refereed)
    Abstract [en]

    Epoxidation of oleic acid and cottonseed oil was conducted in a semibatch reactor with in-situ-formed percarboxylic acid (peracetic acid or perpropionic acid), using hydrogen peroxide as an oxidizing agent and carboxylic acid (acetic acid or propionic acid) as oxygen carriers. Amberlite IR-120 was implemented as the catalyst. The system was comprised of a loop reactor, where the mixture was pumped through a single-mode cavity in which microwave irradiation was introduced. A heat exchanger was integrated into the system to replace microwave heating, to compare the results obtained via microwave heating versus conventional heating. The catalyst loading effect was studied, as well as the influence of microwave irradiation and the implementation of the SpinChem rotating bed reactor (RBR), in hopes of decreasing the influence of the internal mass transfer. The application of microwave irradiation results in an improvement of the reaction yield in the absence of a catalyst.

78910111213 451 - 500 of 87282
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