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  • 501. 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.

  • 502.
    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.

  • 503.
    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.

  • 504.
    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.

  • 505.
    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.

  • 506. 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.

  • 507. Aguilera, Adriana Freites
    et al.
    Tolvanen, Pasi
    Oger, Adrien
    Eränen, Kari
    Leveneur, Sébastien
    Mikkola, Jyri-Pekka
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Laboratory of Industrial Chemistry and Reaction Engineering, Department of Chemical Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Turku-Åbo, Finland.
    Salmi, Tapio
    Screening of ion exchange resin catalysts for epoxidation of oleic acid under the influence of conventional and microwave heating2019In: Journal of chemical technology and biotechnology (1986), ISSN 0268-2575, E-ISSN 1097-4660, Vol. 94, no 9, p. 3020-3031Article in journal (Refereed)
    Abstract [en]

    Background: For many chemical systems, it is of great importance to find a durable, active and efficient catalyst that improves the process performance. Epoxidation of oleic acid with peracetic acid (Prilezhaev oxidation) was carried out in an isothermal loop reactor in the presence of heterogeneous catalysts. The kinetic experiments conducted under microwave heating (MW) were compared with identical experiments carried out under conventional (conductive/convective) heating. Extensive screening of heterogeneous catalysts was conducted and the influence of microwave irradiation on the reaction kinetics was studied. Several ion exchange resins were screened to explore their applicability and activity in the epoxidation of oleic acid. The perhydrolysis reaction (peracetic acid formed in situ from acetic acid and H2O2) was promoted with the use of various solid acid catalysts: Amberlite IR-120, Amberlyst 15, Smopex®, Dowex 50x8-100, Dowex 50x8-50, Dowex 50x2-100 and Nafion™.

    Results: From the selected group of catalysts, Dowex 50-x8100 and Dowex 50x8-50 produced the highest yield of epoxidized oil. Only minor differences in the reactant conversion and the product yield were found in the experiments carried out under microwave exposure compared to the conventionally heated experiments in the presence of several ion exchange resins.

    Conclusions: The catalytic effect was much more prominent than the microwave effect, because the solid acid catalysts enhanced the slow step of the process, the perhydrolysis of acetic acid. The catalytic effect was very dominant and a considerable improvement of the oleic acid conversion and the epoxide yield was observed in the presence of the top-performing catalysts.

  • 508. Aguilo, Francesca
    et al.
    Avagyan, Serine
    Labar, Amy
    Sevilla, Ana
    Lee, Dung-Fang
    Kumar, Parameet
    Lemischka, Ihor R
    Zhou, Betty Y
    Snoeck, Hans-Willem
    Prdm16 is a physiologic regulator of hematopoietic stem cells.2011In: Blood, ISSN 0006-4971, E-ISSN 1528-0020, Vol. 117, no 19Article in journal (Refereed)
    Abstract [en]

    Fetal liver and adult bone marrow hematopoietic stem cells (HSCs) renew or differentiate into committed progenitors to generate all blood cells. PRDM16 is involved in human leukemic translocations and is expressed highly in some karyotypically normal acute myeloblastic leukemias. As many genes involved in leukemogenic fusions play a role in normal hematopoiesis, we analyzed the role of Prdm16 in the biology of HSCs using Prdm16-deficient mice. We show here that, within the hematopoietic system, Prdm16 is expressed very selectively in the earliest stem and progenitor compartments, and, consistent with this expression pattern, is critical for the establishment and maintenance of the HSC pool during development and after transplantation. Prdm16 deletion enhances apoptosis and cycling of HSCs. Expression analysis revealed that Prdm16 regulates a remarkable number of genes that, based on knockout models, both enhance and suppress HSC function, and affect quiescence, cell cycling, renewal, differentiation, and apoptosis to various extents. These data suggest that Prdm16 may be a critical node in a network that contains negative and positive feedback loops and integrates HSC renewal, quiescence, apoptosis, and differentiation.

  • 509.
    Aguilo, Francesca
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology. Departments of Structural and Chemical Biology, Genetics and Genomic Sciences and Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
    Di Cecilia, Serena
    Walsh, Martin J
    Long Non-coding RNA ANRIL and Polycomb in Human Cancers and Cardiovascular Disease2016In: Long non-coding RNAs in human disease, Springer, 2016, Vol. 394, p. 29-39Chapter in book (Refereed)
    Abstract [en]

    The long non-coding RNA CDKN2B-AS1, commonly referred to as the Antisense Non-coding RNA in the INK4 Locus (ANRIL), is a 3.8-kb-long RNA transcribed from the short arm of human chromosome 9 on p21.3 that overlaps a critical region encompassing three major tumor suppressor loci juxtaposed to the INK4b-ARF-INK4a gene cluster and the methyl-thioadenosine phosphorylase (MTAP) gene. Genome-wide association studies have identified this region with a remarkable and growing number of disease-associated DNA alterations and single nucleotide polymorphisms, which corresponds to increased susceptibility to human disease. Recent attention has been devoted on whether these alterations in the ANRIL sequence affect its expression levels and/or its splicing transcript variation, and in consequence, global cellular homeostasis. Moreover, recent evidence postulates that ANRIL not only can regulate their immediate genomic neighbors in cis, but also has the capacity to regulate additional loci in trans. This action would further increase the complexity for mechanisms imposed through ANRIL and furthering the scope of this lncRNA in disease pathogenesis. In this chapter, we summarize the most recent findings on the investigation of ANRIL and provide a perspective on the biological and clinical significance of ANRIL as a putative biomarker, specifically, its potential role in directing cellular fates leading to cancer and cardiovascular disease.

  • 510.
    Aguilo, Francesca
    et al.
    Icahn School of Medicine at Mount Sinai, New York, NY, USA.
    Li, SiDe
    Balasubramaniyan, Natarajan
    Sancho, Ana
    Benko, Sabina
    Zhang, Fan
    Vashisht, Ajay
    Rengasamy, Madhumitha
    Andino, Blanca
    Chen, Chih-hung
    Zhou, Felix
    Qian, Chengmin
    Zhou, Ming-Ming
    Wohlschlegel, James A
    Zhang, Weijia
    Suchy, Frederick J
    Walsh, Martin J
    Deposition of 5-Methylcytosine on Enhancer RNAs Enables the Coactivator Function of PGC-1α2016In: Cell reports, ISSN 2211-1247, E-ISSN 2211-1247, Vol. 14, no 3, p. 479-492Article in journal (Refereed)
    Abstract [en]

    The Peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (PGC-1α) is a transcriptional co-activator that plays a central role in adapted metabolic responses. PGC-1α is dynamically methylated and unmethylated at the residue K779 by the methyltransferase SET7/9 and the Lysine Specific Demethylase 1A (LSD1), respectively. Interactions of methylated PGC-1α[K779me] with the Spt-Ada-Gcn5-acetyltransferase (SAGA) complex, the Mediator members MED1 and MED17, and the NOP2/Sun RNA methytransferase 7 (NSUN7) reinforce transcription, and are concomitant with the m(5)C mark on enhancer RNAs (eRNAs). Consistently, loss of Set7/9 and NSun7 in liver cell model systems resulted in depletion of the PGC-1α target genes Pfkl, Sirt5, Idh3b, and Hmox2, which was accompanied by a decrease in the eRNAs levels associated with these loci. Enrichment of m(5)C within eRNA species coincides with metabolic stress of fasting in vivo. Collectively, these findings illustrate the complex epigenetic circuitry imposed by PGC-1α at the eRNA level to fine-tune energy metabolism.

  • 511.
    Aguilo, Francesca
    et al.
    Umeå University, Faculty of Medicine, Wallenberg Centre for Molecular Medicine at Umeå University (WCMM). Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology. Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
    Walsh, Martin J.
    The N6-Methyladenosine RNA modification in pluripotency and reprogramming2017In: Current Opinion in Genetics and Development, ISSN 0959-437X, E-ISSN 1879-0380, Vol. 46, p. 77-82Article, review/survey (Refereed)
    Abstract [en]

    Chemical modifications of RNA provide a direct and rapid way to manipulate the existing transcriptome, allowing rapid responses to the changing environment further enriching the regulatory capacity of RNA. N-6-Methyladenosine(m(6)A) has been identified as the most abundant internal modification of messenger RNA in eukaryotes, linking external stimuli to an intricate network of transcriptional, post-transcriptional and translational processes. M(6)A modification affects a broad spectrum of cellular functions, including maintenance of the pluripotency of embryonic stem cells (ESCs) and the reprogramming of somatic cells into induced pluripotent stem cells (iPSCs). In this review, we summarize the most recent findings on m(6)A modification with special focus on the different studies describing how m(6)A is implicated in ESC self-renewal, cell fate specification and iPSC generation.

  • 512.
    Aguilo, Francesca
    et al.
    Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
    Zakirova, Zuchra
    Nolan, Katie
    Wagner, Ryan
    Sharma, Rajal
    Hogan, Megan
    Wei, Chengguo
    Sun, Yifei
    Walsh, Martin J.
    Kelley, Kevin
    Zhang, Weijia
    Ozelius, Laurie J.
    Gonzalez-Alegre, Pedro
    Zwaka, Thomas P.
    Ehrlich, Michelle E.
    THAP1: Role in Mouse Embryonic Stem Cell Survival and Differentiation2017In: Stem Cell Reports, ISSN 2213-6711, Vol. 9, no 1, p. 92-107Article in journal (Refereed)
    Abstract [en]

    THAP1 (THAP [Thanatos-associated protein] domain-containing, apoptosis-associated protein 1) is a ubiquitously expressed member of a family of transcription factors with highly conserved DNA-binding and protein-interacting regions. Mutations in THAP1 cause dystonia, DYT6, a neurologic movement disorder. THAP1 downstream targets and the mechanism via which it causes dystonia are largely unknown. Here, we show that wild-type THAP1 regulates embryonic stem cell (ESC) potential, survival, and proliferation. Our findings identify THAP1 as an essential factor underlying mouse ESC survival and to some extent, differentiation, particularly neuroectodermal. Loss of THAP1 or replacement with a disease-causing mutation results in an enhanced rate of cell death, prolongs Nanog, Prdm14, and/or Rex1 expression upon differentiation, and results in failure to upregulate ectodermal genes. ChIP-Seq reveals that these activities are likely due in part to indirect regulation of gene expression.

  • 513. Aguilo, Francesca
    et al.
    Zhang, Fan
    Sancho, Ana
    Fidalgo, Miguel
    Di Cecilia, Serena
    Vashisht, Ajay
    Lee, Dung-Fang
    Chen, Chih-Hung
    Rengasamy, Madhumitha
    Andino, Blanca
    Jahouh, Farid
    Roman, Angel
    Krig, Sheryl R
    Wang, Rong
    Zhang, Weijia
    Wohlschlegel, James A
    Wang, Jianlong
    Walsh, Martin J
    Coordination of m(6)A mRNA Methylation and Gene Transcription by ZFP217 Regulates Pluripotency and Reprogramming.2015In: Cell Stem Cell, ISSN 1934-5909, E-ISSN 1875-9777, Vol. 17, no 6, p. 689-704Article in journal (Refereed)
    Abstract [en]

    Epigenetic and epitranscriptomic networks have important functions in maintaining the pluripotency of embryonic stem cells (ESCs) and somatic cell reprogramming. However, the mechanisms integrating the actions of these distinct networks are only partially understood. Here we show that the chromatin-associated zinc finger protein 217 (ZFP217) coordinates epigenetic and epitranscriptomic regulation. ZFP217 interacts with several epigenetic regulators, activates the transcription of key pluripotency genes, and modulates N6-methyladenosine (m(6)A) deposition on their transcripts by sequestering the enzyme m(6)A methyltransferase-like 3 (METTL3). Consistently, Zfp217 depletion compromises ESC self-renewal and somatic cell reprogramming, globally increases m(6)A RNA levels, and enhances m(6)A modification of the Nanog, Sox2, Klf4, and c-Myc mRNAs, promoting their degradation. ZFP217 binds its own target gene mRNAs, which are also METTL3 associated, and is enriched at promoters of m(6)A-modified transcripts. Collectively, these findings shed light on how a transcription factor can tightly couple gene transcription to m(6)A RNA modification to ensure ESC identity.

  • 514. Aguilo, Francesca
    et al.
    Zhou, Ming-Ming
    Walsh, Martin J
    Long noncoding RNA, polycomb, and the ghosts haunting INK4b-ARF-INK4a expression.2011In: Cancer Research, ISSN 0008-5472, E-ISSN 1538-7445, Vol. 71, no 16Article in journal (Refereed)
    Abstract [en]

    Polycomb group proteins (PcG) function as transcriptional repressors of gene expression. The important role of PcG in mediating repression of the INK4b-ARF-INK4a locus, by directly binding to the long noncoding RNA (lncRNA) transcript antisense noncoding RNA in the INK4 locus (ANRIL), was recently shown. INK4b-ARF-INK4a encodes 3 tumor-suppressor proteins, p15(INK4b), p14(ARF), and p16(INK4a), and its transcription is a key requirement for replicative or oncogene-induced senescence and constitutes an important barrier for tumor growth. ANRIL gene is transcribed in the antisense orientation of the INK4b-ARF-INK4a gene cluster, and different single-nucleotide polymorphisms are associated with increased susceptibility to several diseases. Although lncRNA-mediated regulation of INK4b-ARF-INK4a gene is not restricted to ANRIL, both polycomb repressive complex-1 (PRC1) and -2 (PRC2) interact with ANRIL to form heterochromatin surrounding the INK4b-ARF-INK4a locus, leading to its repression. This mechanism would provide an increased advantage for bypassing senescence, sustaining the requirements for the proliferation of stem and/or progenitor cell populations or inappropriately leading to oncogenesis through the aberrant saturation of the INK4b-ARF-INK4a locus by PcG complexes. In this review, we summarize recent findings on the underlying epigenetic mechanisms that link PcG function with ANRIL, which impose gene silencing to control cellular homeostasis as well as cancer development.

  • 515. Aguiló, Francesca
    et al.
    Camarero, Nuria
    Relat, Joana
    Marrero, Pedro F
    Haro, Diego
    Transcriptional regulation of the human acetoacetyl-CoA synthetase gene by PPARgamma.2010In: Biochemical Journal, ISSN 0264-6021, E-ISSN 1470-8728, Vol. 427, no 2Article in journal (Refereed)
    Abstract [en]

    In the cytosol of lipogenic tissue, ketone bodies are activated by AACS (acetoacetyl-CoA synthetase) and incorporated into cholesterol and fatty acids. AACS gene expression is particularly abundant in white adipose tissue, as it is induced during adipocyte differentiation. In order to elucidate the mechanism controlling the gene expression of human AACS and to clarify its physiological role, we isolated the human promoter, characterized the elements required to initiate transcription and analysed the expression of the gene in response to PPARgamma (peroxisome-proliferator-activated receptor gamma), an inducer of adipogenesis. We show that the human AACS promoter is a PPARgamma target gene and that this nuclear receptor is recruited to the AACS promoter by direct interaction with Sp1 (stimulating protein-1).

  • 516.
    Aguirre Nunez, William
    Umeå University, Faculty of Social Sciences, Umeå School of Business.
    Should I stay or Should I go?: –En studie om småföretagares val att göra digitala marknadsföringssatsningar på Internet2010Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syftet med studien är att få en ökad kunskap om varför småföretag väljer att börja medmarknadsföringsinsatser på Internet. Helt enkelt få insikt om vad som drivit småföretag att ta steget till att implementera Internet till sin verksamhet. För att se hur det hör ihop med att valav aktiviteter och verktyg som används i marknadsföringssyfte. Även se om det görs någon form av uppföljning av de olika processerna.

  • 517. Aguirre-Hernandez, Baltazar
    et al.
    Campos-Canton, Eric
    Villafuerte-Segura, Raul
    Vazquez, Carlos
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Loredo-Villalobos, Carlos-Arturo
    Open Challenges on the Stability of Complex Systems: Insights of Nonlinear Phenomena with or without Delay2019In: Complexity, ISSN 1076-2787, E-ISSN 1099-0526, article id 5209636Article in journal (Other academic)
  • 518.
    Agvald, Liv
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Sports medicine.
    Fysisk aktivitetsnivå hos barn i årskurs 3: En accelerometerstudie2018Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Introduction: The importance of physical activity is well investigated, but the knowledge regarding the physical activity of younger children is limited. Accelerometers have proved to be a valid method to measure physical activity in children.

    Purpose: The purpose of this study was to investigate the total level of physical activity (relative to recommended level) in children in grade three at a school in northern Sweden. Furthermore, the study investigated whether there are any differences in physical activity based on gender or participation in organized sports.

    Method: Forty children participated in the study. Their level of physical activity was measured using tri-accelerometry technology during one week. Each participant also completed a short questionnaire regarding their level of physical activity.

    Results: No significant difference was found in the level of physical activity in relation to gender or participation in organized sports. All but one participant reached the recommended level of daily activity.

    Discussion: Based on the study, children in grade three appear to be sufficiently active to achieve the daily level of activity, a positive result in spite of the alarming reports of increased sedentary behavior among children. Intensified studies are needed to see if these results recur in a broader context.

  • 519.
    Agvik, Simon
    Umeå University, Faculty of Science and Technology, Department of Physics.
    A deformable terrain model in multi-domain dynamics using elastoplastic constraints: An adaptive approach2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Achieving realistic simulations of terrain vehicles in their work environment does not only require a careful model of the vehicle itself but the vehicle's interactions with the surroundings are equally important. For off-road ground vehicles the terrain will heavily affect the behaviour of the vehicle and thus puts great demands on the terrain model.

    The purpose of this project has been to develop and evaluate a deformable terrain model, meant to be used in real-time simulations with multi-body dynamics. The proposed approach is a modification of an existing elastoplastic model based on linear elasticity theory and a capped Drucker-Prager model, using it in an adaptive way. The original model can be seen as a system of rigid bodies connected by elastoplastic constraints, representing the terrain. This project investigates if it is possible to create dynamic bodies just when it is absolutely necessary, and store information about possible deformations in a grid.

    Two methods used for transferring information between the dynamic bodies and the grid have been evaluated; an interpolating approach and a discrete approach. The test results indicate that the interpolating approach is preferable, with better stability to an equal performance cost. However, stability problems still exist that have to be solved if the model should be useful in a commercial product.

  • 520.
    Agyeman, Stephen Kwaning
    Umeå University, Faculty of Social Sciences, Umeå School of Business.
    Challenges facing venture capitalists in developing economies: An empirical study about venture capital industry in Ghana2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 521. Ahad, Abdul
    et al.
    Keech, Olivier
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Sjödin, Andreas
    Lindén, Pernilla
    Brouwer, Bastiaan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Stenlund, Hans
    Moritz, Thomas
    Jansson, Stefan
    Gardeström, Per
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Comparison between leaves from darkened plants and individually-darkened leaves reveals differential metabolic strategies in response to darknessManuscript (preprint) (Other academic)
  • 522. Ahad, Abdul
    et al.
    Keech, Olivier
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre.
    Sjödin, Andreas
    Stenlund, Hans
    Moritz, Thomas
    Jansson, Stefan
    Gardeström, Per
    Leaf metabolism during dark induced senescence in Arabidopsis: integrating metabolomics and transcriptomicsManuscript (Other academic)
  • 523.
    Ahad, Abdul
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Nick, Peter
    Actin is bundled in activation-tagged tobacco mutants that tolerate aluminum2007In: Planta, ISSN 0032-0935, E-ISSN 1432-2048, Vol. 225, no 2, p. 451-468Article in journal (Refereed)
    Abstract [en]

    A panel of aluminum-tolerant (AlRes) mutants was isolated by protoplast-based T-DNA activation tagging in the tobacco cultivar SR1. The mutants fell into two phenotypic classes: a minority of the mutants were fertile and developed similarly to the wild type (type I), the majority was male-sterile and grew as semi-dwarfs (type II). These traits, along with the aluminum tolerance, were inherited in a monogenic dominant manner. Both types of mutants were characterized by excessive bundling of actin microfilaments and by a strongly increased abundance of actin, a phenotype that could be partially phenocopied in the wild type by treatment with aluminum chloride. The actin bundles could be dissociated into finer strands by addition of exogenous auxin in both types of mutants. However, actin microfilaments and leaf expansion were sensitive to blockers of actin assembly in the wild type and in the mutants of type I, whereas they were more tolerant in the mutants of type II. The mutants of type II displayed a hypertrophic development of vasculature, manifest in form of supernumerary leaf veins and extended xylem layers in stems and petioles. Whereas mutants of type I were characterized by a normal, but aluminum-tolerant polar auxin-transport, auxin-transport was strongly promoted in the mutants of type II. The phenotype of these mutants is discussed in terms of reduced endocytosis leading, concomitantly with aluminum tolerance, to changes in polar auxin transport.

  • 524.
    Ahangari, Alebtekin
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Chronic pelvic pain: 8 years after the 2006 WHO systematic review2013Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
  • 525.
    Ahangari, Alebtekin
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Pain and Alcohol Consumption among Elderly: Evidences from WHO Study on global AGEing and adult health (Wave 1)2014Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
  • 526.
    Ahangari, Alebtekin
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Prevalence of Chronic Pelvic Pain Among Women: An Updated Review2014In: Pain Physician, ISSN 1533-3159, E-ISSN 2150-1149, Vol. 17, no 2, p. E141-E147Article, review/survey (Refereed)
    Abstract [en]

    Background: Chronic pelvic pain (CPP), defined as a noncyclical pain lasting for more than 6 months can lead to lower physical performance and quality of life in women. CPP is a worldwide problem affecting women of all ages. However, health care professionals and researchers, due to its complex nature and the lack of knowledge surrounding the condition, frequently neglect CPP. Subsequently, basic data and knowledge regarding CPP remain incomplete. Objective: To update the review of the worldwide estimation of the CPP prevalence considering the World Health Organization systematic review by Latthe et al in 2006 as point of departure. Study Design: A systematic review of CPP prevalence studies. Method: Electronic search was performed to find related articles through PubMed between 2005 and 2012 based on the PRISMA statement (2009). Results: From 140 studies, only 7 studies were about CPP prevalence. Their study design consisted of 3 cross sectional studies, one population based mailing questionnaire study, one survey study (computer assisted telephone interview), one data analysis by questionnaire, and one prospective community based study. Limitations: Paucity of population based studies in addition to probability of existence of studies at the local level with limited access to worldwide databases, lack of consensus about definition of CPP among researchers and therapists, and non-inclusion of CPP related key words in databases such as PubMed. Conclusion: Based on these articles, prevalence in general ranged between 5.7% and 26.6%. There were many countries and regions without basic data in the field of CPP. This review shows the paucity of studies, especially multidisciplinary researches with multifactorial views on CPP. Multidisciplinary studies would provide more reliable data for estimating the prevalence of CPP and its psycho-socioeconomic burden, as well as finding its etiologies and characteristics. This would be the first step towards better treatment and care for women with CPP.

  • 527.
    Ahangari, Alebtekin
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Obstetrics and Gynaecology. Umeå Neurosteroid Research Center, Umeå University, Umeå, Sweden.
    Bäckström, Torbjörn
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Obstetrics and Gynaecology. Umeå Neurosteroid Research Center, Umeå University, Umeå, Sweden.
    Innala, Eva
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Obstetrics and Gynaecology. Umeå Neurosteroid Research Center, Umeå University, Umeå, Sweden.
    Andersson, C.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Obstetrics and Gynaecology. Umeå Neurosteroid Research Center, Umeå University, Umeå, Sweden.
    Turkmen, Sahruh
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Obstetrics and Gynaecology. Umeå Neurosteroid Research Center, Umeå University, Umeå, Sweden.
    Acute intermittent porphyria symptoms during the menstrual cycle2015In: Internal medicine journal (Print), ISSN 1444-0903, E-ISSN 1445-5994, Vol. 45, no 7, p. 725-731Article in journal (Refereed)
    Abstract [en]

    Background: Acute intermittent porphyria (AIP), a life-threatening form of the disease, is accompanied by several pain, mental and physical symptoms.

    Aims: In this study, we evaluated the cyclicity of AIP and premenstrual syndrome (PMS) symptoms in 32 women with DNA-diagnosed AIP during their menstrual cycles, in northern Sweden.

    Methods: The cyclicity of AIP symptoms and differences in them between the follicularand luteal phases, and the cyclicity of each symptom in each individual woman indifferent phases of her menstrual cycle were analysed with a prospective daily ratingquestionnaire. PMS symptoms were also evaluated in the patients on a daily rating scale.

    Results: Of the 32 women, 30 showed significant cyclicity in at least one AIP or PMS symptom (P < 0.05–0.001). Back pain (10/32) was the most frequent AIP pain symptomand sweet craving (10/15) was the most frequent PMS symptom. Pelvic pain (F = 4.823,P = 0.036), irritability (F = 7.399, P = 0.011), cheerfulness (F = 5.563, P = 0.025), sexualdesire (F = 8.298, P = 0.007), friendliness (F = 6.157, P = 0.019), breast tenderness (F =21.888, P = 0.000) and abdominal swelling (F = 16.982, P = 0.000) showed significantcyclicity. Pelvic pain and abdominal swelling (rs= 0.337, P < 0.001) showed the strongest correlation. The age of women with latent AIP was strongly correlated with abdominal swelling during the luteal phase (rs= 0.493, P < 0.01).

    Conclusion: Our results suggest that the symptoms of AIP patients change during their menstrual cycles.

  • 528.
    Ahangari, Alebtekin
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Stewart Williams, Jennifer
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Research Centre for Generational, Health and Ageing, School of Medicine and Public Health, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, Australia.
    Myléus, Anna
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Family Medicine.
    Pain and alcohol consumption among older adults: findings from the World Health Organization Study on global AGEing and adult health, Wave 12016In: Tropical medicine & international health, ISSN 1360-2276, E-ISSN 1365-3156, Vol. 21, no 10, p. 1282-1292Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: To investigate cross-sectional associations between self-reported recent pain and alcohol use/abstinence, and previous-day pain and previous-week alcohol consumption in adults aged 50 + in six low- and middle-income countries (LMICs). METHODS: The WHO Study on global AGEing and adult health (SAGE) Wave 1 (2007-2010) in China, Ghana, India, Mexico, Russia and South Africa is the data source. Prevalence of alcohol use/abstinence is reported by previous-day and previous-month pain. Multinomial logistic regressions (crude and adjusted for sex and country) tested associations between recent pain and alcohol use in the pooled multicountry sample. RESULTS: Across the six SAGE countries, about one-third of respondents reported alcohol use, being highest in Russia (74%) and lowest in India (16%). Holding the effects of sex and country constant, compared with abstainers, people with previous-day pain were more likely to be previous-day or other users. With regard to the quantity and frequency of alcohol use, people with previous-day pain were more likely to be non-heavy drinkers. CONCLUSION: Overall, we found that, in this population of older adults in six LMICs, recent pain was associated with moderate use of alcohol, although there were differences between countries. The findings provide a platform for country-specific research to better understand bi-directional associations between pain and alcohol in older adults.

  • 529.
    Ahava, Harri
    et al.
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Brännström, Tomas
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Videokonferenser – Ett naturligt sätt att mötas? 1997Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 530.
    Ahl, Astrid
    Umeå University, Faculty of Social Sciences, Education.
    Equality and the freedom to choose the 'what and when' of schooling: Students with special educational needs in timetable-free settings2007In: European Journal of Special Needs Education, ISSN 0885-6257, Vol. 22, no 2, p. 183-197Article in journal (Refereed)
  • 531.
    Ahl, Astrid
    Umeå University, Faculty of Social Sciences, Department of Education.
    Läraren och läsundervisningen: En studie av åldersintegrerad pedagogisk praktik med sex- och sjuåringar1998Doctoral thesis, monograph (Other academic)
    Abstract [en]

    This dissertation is about reading instruction in six mixed-aged classes, called child schools, with six and seven year old children. The overall questions of this study were: How did the teachers in child schools organise work in general and reading instruction in particular? How did they handle for example the increasing range of variation concerning knowledge and skills that goes together with increasing variation of age? With respect to reading the investigation also examined the content of reading instruction and the extent to which teachers took into account those factors that, according to reading research, are important for the acquisition of reading skills? Overall the research aimed to examine how the reading ability of the pupils developed during their first years at school. Six child schools were included in the study. The data collection extended over three years and contained field studies, interviews with the staff and reading tests with the pupils. Reading theories were used to analyse the form of the reading instruction and Basil Bernstein's theory of visible and invisible pedagogy was used to analyse pedagogical practice in its context. With one exception a visible pedagogy dominated in all the child schools. During lessons designated "my own work" the pupils were allowed to plan their work. This weak framing allowed the pupils to sort themselves into groups of more or less successful learners. In reading instruction, elements of two different models for instruction were combined, e.g. the whole language and the basal reading approach. My conclusion is that this combination is effective in a mixed-age group. Pupils at different competence levels benefit from different approaches. The reading comprehension of the child school pupils did not differ from the levels obtained with comparable pupils in national surveys. The test results, like the learning conditions varied between the schools. In my view the test results were not merely a consequence of the instruction, but also of other circumstances that interacted with the pedagogy.

  • 532.
    Ahl, Astrid
    Umeå University, Faculty of Social Sciences, Education.
    Practitioner research for increased inclusion2004In: The European Conference on Educational Research, University of Crete, 22-25 September 2004, 2004Conference paper (Other academic)
  • 533.
    Ahl, Astrid
    Umeå University, Faculty of Social Sciences, Education.
    TUFI-projektet: tidig upptäckt - förebyggande insatser: En handlingsplan för den förberedande och grundläggande läs- och skrivundervisningen. Skolan i Umeå2002Report (Other academic)
  • 534.
    Ahl, Astrid
    Umeå University, Faculty of Social Sciences, Education.
    Utvärdering av specialpedagogfunktionen, Örnsköldsviks kommun2004Report (Other academic)
  • 535.
    Ahl, Astrid
    et al.
    Umeå University, Faculty of Social Sciences, Department of Education.
    Andersson, Håkan
    Umeå University, Faculty of Social Sciences, Department of Education.
    From, Jörgen
    Umeå University, Faculty of Social Sciences, Department of Education.
    Holmgren, Carina
    Umeå University, Faculty of Social Sciences, Department of Education.
    Johansson, Ulla
    Umeå University, Faculty of Social Sciences, Department of Education.
    Tid som frihet – tid som tvång: Fostran, bedömning och elevers behov i den mål- och resultatstyrda svenska grundskolan2005In: SOU 2005:102 Utan timplan - forskning och utvärdering: Antologi från Timplanedelegationen, Fritzes, Stockholm , 2005, p. 173-196Chapter in book (Other academic)
  • 536.
    Ahl, Astrid
    et al.
    Umeå University, Faculty of Social Sciences, Education.
    Andersson, Håkan
    Umeå University, Faculty of Social Sciences, Education.
    Johansson, Ulla
    Umeå University, Faculty of Social Sciences, Education.
    The logic of time allocation in Swedish timetable free schools; the interplay between grading criteria, students´ needs and the need for time discipline2005In: The ECER- conference i Dublin, 7-10 september, 2005, 2005Conference paper (Other academic)
  • 537.
    Ahl, Astrid
    et al.
    Umeå University, Faculty of Social Sciences, Education.
    Backman, Jarl
    Umeå University, Faculty of Social Sciences, Education.
    An Evaluation of the Role of Resource Persons in a Venture to Increase IT Access for Disabled Pupils2003In: ED-MEDIA, World Conference on Educational Multimedia, Hypermedia & Telecommunication, Honolulu, Hawai USA, June 27; 2003, 2003Conference paper (Other academic)
  • 538.
    Ahl, Astrid
    et al.
    Umeå University, Faculty of Social Sciences, Education.
    Backman, Jarl
    Umeå University, Faculty of Social Sciences, Education.
    Resurspersoner i särskild satsning på IT för elever med funktionshinder: En utvärdering2002Report (Other academic)
  • 539.
    Ahl, Astrid
    et al.
    Umeå University, Faculty of Social Sciences, Education.
    Nilsson, Ingrid
    Umeå University, Faculty of Social Sciences, Education.
    Changes in Teacher Education in Sweden: Some Inplications for Special Education2000In: The 25th ATEE Annual Conference, Barcelona, 2000Conference paper (Other academic)
  • 540.
    Ahl, Astrid
    et al.
    Umeå University, Faculty of Social Sciences, Education.
    Nilsson, Ingrid
    Umeå University, Faculty of Social Sciences, Education.
    Teacher Education for the New Century in Sweden2000In: European Journal of Teacher Education, ISSN 0261-9768, Vol. 23, no 2, p. 117-125Article in journal (Refereed)
  • 541.
    Ahl, Astrid
    et al.
    Umeå University, Faculty of Social Sciences, Department of applied educational science.
    Olofsson, Åke
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Taube, Karin
    Umeå University, Faculty of Arts, Department of language studies.
    Studenter med dyslexi inom högre utbildning i Sverige och Storbritannien2010In: Dyslexi : aktuellt om läs- och skrivsvårigheter, ISSN 1401-2480, no 3, p. 4-9Article in journal (Other academic)
  • 542.
    Ahl, Caroline
    et al.
    Umeå University, Faculty of Medicine, Department of Nursing.
    Nyström, Maria
    To handle the unexpected: the meaning of caring in pre-hospital emergency care2012In: International Emergency Nursing, ISSN 1755-599X, E-ISSN 1878-013X, Vol. 20, no 1, p. 33-41Article, review/survey (Refereed)
    Abstract [en]

    The patient's voice has not been present to the same degree as the professional perspective in caring research in a pre-hospital context. In order to further develop and improve pre-hospital care, it is therefore important to explore patients' situations not only in life threatening but also in non-traumatic situations. This is especially important as these patients might be defined as inappropriate attendees of ambulance services. The aim of this study was to interpret and explain experiences of caring in pre-hospital care situations that are not defined as traumatic or life threatening. Twenty informants aged between 34 and 82 years were interviewed. The design of the study was exploratory, and it used an interpretative approach in order to understand the meaning of pre-hospital caring. The findings show that pre-hospital caring can be understood and explained as a matter of interplay between carer(s) and patient with potentials for positive as well as negative outcomes. Our conclusion is that the initial meeting is of vital importance in how patients experience pre-hospital care. It is suggested that general public information on the development of Swedish pre-hospital care received in turn may facilitate the first encounter between patient and carer(s). 

  • 543.
    Ahl, Caroline
    et al.
    Umeå University, Faculty of Medicine, Department of Nursing. School of Health Sciences, University Collage of Borås, SE-501, 90 Borås, Sweden.
    Nyström, Maria
    Jansson, Lilian
    Umeå University, Faculty of Medicine, Department of Nursing.
    Making up one's mind: patients' experiences of calling an ambulance2006In: Accident and Emergency Nursing, ISSN 0965-2302, E-ISSN 1532-9267, Vol. 14, no 1, p. 11-19Article in journal (Refereed)
    Abstract [en]

    The issue of the inappropriate use of ambulance transport and care has mainly been studied from the professionals' and caregivers' perspective, with few studies focusing on the patient and his/her experiences. To further understand whether patients use ambulance care in an inappropriate manner and, if so, why, it is important to obtain an overall picture of the patients' existential situation at the time they call an ambulance. The aim of this study was to analyse and describe patients' experiences related to the decision to call an ambulance and the wait for it to arrive. The design was explorative, and twenty informants aged between 34 and 82 years were interviewed. Qualitative content analyses were performed. The findings showed that calling for an ambulance is a major decision that is preceded by hesitation and attempts to handle the situation by oneself. Our conclusion is that the definition of inappropriate use of valuable health care resources should not be based solely on the professionals' point of view but also take account of the patients' reactions when they experience a threat to their life and health.

  • 544. Ahl, Ing-Marie
    et al.
    Lindberg, Mikael J
    Umeå University, Faculty of Science and Technology, Chemistry.
    Tibell, Lena A E
    Coexpression of yeast copper chaperone (yCCS) and CuZn-superoxide dismutases in Escherichia coli yields protein with high copper contents2004In: Protein Expression and Purification, ISSN 1046-5928, E-ISSN 1096-0279, Vol. 37, no 2, p. 311-9Article in journal (Refereed)
    Abstract [en]

    To fully understand the function of the Cu- and Zn-containing superoxide dismutases in normal and disordered cells, it is essential to study protein variants with full metal contents. We describe the use of an Escherichia coli-based expression system for the overproduction of human intracellular wild type CuZn-superoxide dismutase (SOD), the CuZnSOD variant F50E/G51E (monomeric), two amyotrophic lateral sclerosis-related mutant CuZnSOD variants (D90A and G93A), and PseudoEC-SOD, all with high Cu contents. This system is based on coexpression of the SOD variants with the yeast copper chaperone yCCS during growth in a medium supplemented with Cu(2+) and Zn(2+). The recombinant SOD enzymes were all found in the cytosol and represented 30-50% of the total bacterial protein. The enzymes were purified to homogeneity and active enzymes were obtained in high yield. The resulting proteins were characterized through immunochemical reactivity and specific activity analyses, in conjunction with mass-, photo-, and atomic absorption-spectroscopy.

  • 545.
    Ahl, Johan
    et al.
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Swartz, Mattias
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    När genväg blir omväg: En kvalitativ studie om workarounds komplexa natur och dess mångsidiga konsekvenser i en ISO-certifierad organisation2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This qualitative study examines positive and negative effects on effectivity as a result of alternative processes (workarounds) performed within an ISO-certificated organizations information system. To identify these workarounds we used contextual inquiry. This gave us an understanding of how the information systems users actually practice their work. The result of our acquired data revealed six major workarounds. To analyze these workarounds in relation to its complicated context we utilized three theoretical models. This gave us a broad understanding of each of the workarounds and made it possible to understand why each workaround was conducted, its implications on effectivity and what kind of a challenge/dilemma it posed. The analysis indicated that the workarounds had what we deduced as negative impact on the organizations effectivity as a whole. Many of the workarounds could have been seen as very effective alternatives to the designed work process but only if valued in a micro-context. The fact that they still occur are most likely the result of the fact that the users of the information system lack understanding of how the organization and its processes are structured as a whole and how their work as well as how they perform it is part of a bigger picture. Finally we present how future research, based on this study, could focus on developing a better model to understand the complicated context. We also propose that studies could investigate the possibility of shaping an ISO-standard which is responsive to the diversity of organizations actual work processes while still ensuring a qualitative standard.

  • 546.
    Ahl, Steffen
    Bauhaus Universität Weimar, Deutschland.
    Schwedenhäppchen2001Report (Other academic)
  • 547.
    Ahl, Steffen
    Umeå University, Faculty of Social Sciences, Centre for Regional Science (CERUM).
    Schwedenhäppchen: Ein Forschungseisebericht2001Report (Other academic)
  • 548.
    Ahlbeck, Jakob
    et al.
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Mosebach, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Analys av risker med garantinivåer i förhållande till förväntade utbetalningar och portföljavkastningar för traditionella pensionsförsäkringar: Ett examensarbete för Folksam Liv med dotterbolag2017Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 549.
    Ahlbeck, Thomas
    et al.
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Truedsson, Anders
    Umeå University, Faculty of Social Sciences, Department of Informatics.
    Analysfasen i systemutvecklingen - ett problem?1988Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 550. Ahlberg, Alexander
    et al.
    al-Abany, Massoud
    Alevronta, Eleftheria
    Friesland, Signe
    Hellborg, Henrik
    Mavroidis, Panayiotis
    Lind, Bengt K
    Laurell, Göran
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Otorhinolaryngology.
    Esophageal stricture after radiotherapy in patients with head and neck cancer: experience of a single institution over 2 treatment periods2010In: Head and Neck, ISSN 1043-3074, E-ISSN 1097-0347, Vol. 32, no 4, p. 452-461Article in journal (Refereed)
    Abstract [en]

    Enteral feeding during EBRT is strongly associated with the development of stricture of the esophagus, as is a mean dose of >45 Gy to the upper esophagus. Treatment of the stricture with Savary-Gilliard bougienage or through scope balloon dilatation is safe and successful but often has to be repeated.

891011121314 501 - 550 of 87966
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