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  • 246901. Yue, Ling
    et al.
    Roca-Sanjuán, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Lindh, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Ferré, Nicolas
    Liu, Ya-Jun
    Can the Closed-Shell DFT Methods Describe the Thermolysis of 1,2-Dioxetanone?2012In: Journal of Chemical Theory and Computation, ISSN 1549-9618, E-ISSN 1549-9626, Vol. 8, no 11, p. 4359-4363Article in journal (Refereed)
    Abstract [en]

    The chemiluminescent decomposition of 1,2-dioxetanone has in the past been studied by state-of-the-art multireference quantum chemical calculations, and a stepwise biradical mechanism was established. Recently, this decomposition has been reinvestigated, and a concerted mechanism has been proposed based on calculations performed at the closed-shell density functional theory (DFT) level of theory. In order to solve this apparent mechanistic contradiction, the present paper presents restricted and unrestricted DFT results obtained using functionals including different amounts of Hartree–Fock (HF) exchange, repeating and complementing the above-mentioned DFT calculations. The calculated results clearly indicate that the closed-shell DFT methods cannot correctly describe the thermolysis of 1,2-dioxetanone. It is found that unrestricted Kohn–Sham reaction energies and barriers are always lower than the ones obtained using a restricted formalism. Hence, from energy principles, the biradical mechanism is found to be prevailing in the understanding of the 1,2-dioxetanone thermolysis.

  • 246902.
    Yuen, Katarina
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    System Aspects of Marine Current Energy Conversion2008Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Free-flowing water currents such as tides and unregulated water courses could contribute to world electricity production given the emergence of robust technical solutions for extracting the energy. At Uppsala University, a concept for converting water currents to electricity using a vertical axis turbine with fixed blade pitch and a direct drive permanentmagnet generator is studied. A system approach is desired, and in this thesis, a first analysis of two system components, the generator and the turbine, is presented. This thesis also deals with some issues concerning the design and construction of a low speed generator for this application. An experimental generator for verification of simulations has been designed and constructed. For the electromagnetic design, a FEM simulation tool has been used. The construction work has given valuable practical experience concerning for example handling permanent magnets and winding the generator with cable. Simulations and measurements of the experimental generator have been carried out for different speeds and loads. The generator can operate at the speeds and loads corresponding to maximum power capture for different turbines for water current velocities between approximately 0.5 and 2.5 m/s. At higher water current velocities the turbines may need to be run at a tip speed ratio that gives a lower power capture in order to limit the electrical currents in the generator, cavitation of the blades, or mechanical loads. Comparisons of measurements and simulations show an agreement. The FEM simulation tool can be used to simulate and design electrical machines with a low electrical frequency, i.e. 2–16 Hz.

  • 246903.
    Yuen, Katarina
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    System Perspectives on Hydro-Kinetic Energy Conversion2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Free-flowing water currents such as tides and unregulated water courses could contribute to world electricity production given the emergence of robust technical solutions for extracting the energy. At Uppsala University, a concept for converting the energy in water currents to electricity using a vertical axis turbine with fixed blade-pitch and a direct-drive permanent magnet generator is studied.

    Technological equipment for extracting energy from water currents can be studied at desktop to some extent, but physical realizations, first in a laboratory setting, and later in a natural aquatic setting, are necessary. For this reason, a laboratory generator has been constructed and evaluated, and an experimental setup comprising turbine, generator and control system has been constructed. The turbine and generator are to be deployed in the Dalälven River in Söderfors, and operated from an on-land control station. The author has worked with constructing and evaluating the low-speed laboratory generator, participated in the design and construction of the Söderfors generator, and designed and constructed the control system for Söderfors.

    The generator design incorporates a low rotational speed, permanent magnets, and many poles, in order to adapt the generator to the nature of water currents. Simulations and experimental data for the laboratory prototype have been compared and show that the simulation tool used is adequate for design studies of this type of generator. The generator has also been shown to be able to operate with the intended turbine design and range of water velocities. The control system to be used in Söderfors has been tested in a laboratory environment. Simulations of the control system show that it should be able to operate the turbine and generator at the desired rotational speeds in water velocities up to about 1.8 m/s. Simulations of the system have also shown that maximizing system power output may not correspond with maximizing turbine power.

    List of papers
    1. Experimental setup: Low speed permanent magnet generator for marine current power conversion
    Open this publication in new window or tab >>Experimental setup: Low speed permanent magnet generator for marine current power conversion
    2007 (English)In: Proceedings of the 26th International Conference on Offshore Mechanics and Arctic Engineering, Vol 5, 2007, p. 459-462Conference paper, Published paper (Refereed)
    Abstract [en]

    Marine currents, e.g. tidal currents, ocean currents and unregulated water courses are characterized by a fairly steady or regular flow and pose a significant potential for electricity generation. An ongoing research project at Uppsala University is looking into an energy conversion system with a vertical axis turbine and a permanent magnet direct drive generator placed directly in the water flow, i.e. without using a dam. This choice of technology is intended to provide a simple and robust system with low maintenance needs and minimal environmental impact. During 2006 an experimental setup has been built. It consists of a frequency converter, a motor and a gearbox to drive the generator, the generator itself, and a resistive load to consume the generated power. The generator is two meters in diameter and is built on an elevated structure over the motor and gearbox. A stainless steel structure supports the cable wound stator. The permanent NdFeB magnets are fastened in milled grooves in the rotor. The experimental setup will be used for verification of a simulation and optimization program.

    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:uu:diva-96613 (URN)000249559500056 ()978-0-7918-4271-3 (ISBN)
    Conference
    26th International Conference on Offshore Mechanics and Arctic Engineering San Diego, CA, JUN 10-15, 2007
    Available from: 2008-01-11 Created: 2008-01-11 Last updated: 2013-01-23Bibliographically approved
    2. A direct drive generator for marine current energy conversion - first experimental results
    Open this publication in new window or tab >>A direct drive generator for marine current energy conversion - first experimental results
    2007 (English)Conference paper, Published paper (Refereed)
    Abstract [en]

    Marine currents can be an effective source for renewable electric energy conversion. In this paper a direct drive permanent magnet synchronous generator capable of being connected to a vertical axis turbine for marine current energy conversion is presented. This 5 kVA, 120 pole, 10 rpm prototype generator was initially designed for ocean current speeds of 1.5 m/s using a finite element based electrical machine design software. Unlike most conventional generators this machine has a cable wound stator. To evaluate the electrical and mechanical performance characteristics of this machine, laboratory experiments are being carried out using a speedcontrolled motor drive system and resistive three phase loads. First measurements of voltage and current show good agreement between the modelled and built generator.

    Place, publisher, year, edition, pages
    Porto, Portugal: , 2007
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:uu:diva-133687 (URN)
    Conference
    European Wave and Tidal Energy Conference
    Available from: 2010-11-15 Created: 2010-11-15 Last updated: 2018-06-04Bibliographically approved
    3. A low-speed generator for energy conversion from marine currents: experimental validation of simulation
    Open this publication in new window or tab >>A low-speed generator for energy conversion from marine currents: experimental validation of simulation
    2008 (English)In: Proceedings of the Institution of mechanical engineers. Part A, journal of power and energy, ISSN 0957-6509, E-ISSN 2041-2967, Vol. 222, no 4, p. 381-388Article in journal (Refereed) Published
    Abstract [en]

    A low-speed permanent magnet (PM) cable wound generator for electrical energy conversion from marine or tidal currents has been designed and constructed. A key feature of this variable speed direct drive generator is its capability to efficiently generate electricity from tidal currents with very low velocities, in the order of 1 m/s. In arriving at an appropriate design for the generator typical characteristics of tidal currents were considered. Using these characteristics as input, and accounting for the electromagnetic losses, detailed computer simulations using a finite-element method software were carried out to come up with the final design. Various parameters that can influence the generator design are presented. An experimental set-up has been constructed based on the above-mentioned design in order to study the electrical and mechanical performance of the generator through a variety of experiments. The power input for this set-up is a variable speed motor, capable of operating the generator at rotational speeds of 0–16 r/min, representing tidal currents with very low velocities. The generator presented in this paper may be beneficial for a better understanding of an appropriate design and layout of tidal energy conversion systems.

    Keywords
    finite-element method, marine currents, permanent magnet generator, tidal power
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:uu:diva-96614 (URN)10.1243/09576509JPE567 (DOI)000258167400005 ()
    Available from: 2008-01-11 Created: 2008-01-11 Last updated: 2017-12-14Bibliographically approved
    4. Matching a permanent magnet synchronous generator to a fixed pitch vertical axis turbine for marine current energy conversion
    Open this publication in new window or tab >>Matching a permanent magnet synchronous generator to a fixed pitch vertical axis turbine for marine current energy conversion
    Show others...
    2009 (English)In: IEEE Journal of Oceanic Engineering, ISSN 0364-9059, E-ISSN 1558-1691, Vol. 34, no 1, p. 24-31Article in journal (Refereed) Published
    Abstract [en]

    Extracting energy from a free-flow marine current using a vertical axis fixed pitch turbine requires a generator that can handle varying speeds and loads, since such a turbine gives maximum power capture for a fixed tip speed ratio. A prototype of such a generator has been designed and constructed. In this paper, its variable speed and load operation is evaluated, both in terms of how the constructed generator performs in relation to simulations, and in terms of how the generator could perform with three different fixed pitch turbines. Measurements of root mean square (RMS) voltage and current differ 10% from simulations. Performance analysis with example turbines shows that the generator can match fixed tip speed ratio operation of several turbines for current speeds between 0.5 and 2.5 m/s.

    Keywords
    Fixed tip speed ratio operation, permanent magnet generators, tidal power generation, variable speed generator, vertical axis turbine
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:uu:diva-96617 (URN)10.1109/JOE.2008.2010658 (DOI)000264618000003 ()
    Available from: 2008-01-11 Created: 2008-01-11 Last updated: 2017-12-14Bibliographically approved
    5. A Permanent Magnet Generator for Energy Conversion from Marine Currents: No Load and Load Experiments
    Open this publication in new window or tab >>A Permanent Magnet Generator for Energy Conversion from Marine Currents: No Load and Load Experiments
    2012 (English)In: ISNR Renewable Energy, ISSN 2090-7451, Vol. 2012, p. 489379-Article in journal (Refereed) Published
    Abstract [en]

    This paper presents experiments and measurements on a low speed permanent magnet cable wound generator for marine currentenergy conversion.Measurements were made for no load and nominal load (4.44Ω/phase) conditions at nominal speed (10 rpm).For either load condition, the magnetic fields in the air gap were also measured. The measurements on the generator werecompared with the corresponding finite element method simulations used to design the machine. It is shown in the paper thatmeasurements and corresponding case simulations show good agreement. At nominal speed, the measured and simulated loadvoltages (nominal load) differ less than 1% for the rms values and less than 5% for peak values. At no load, measured and simulatedvoltages had larger differences, that is, <9% for rms values and <5% for peak values. Harmonic analyses of measured and simulatedphase voltages and currents show only the presence of third harmonics. The percentage of harmonics in the measured data wascomparable with the corresponding predictions of the simulations. The discussions and results presented in the paper could bebeneficial for future design of efficient and reliable marine current energy converter systems.

    National Category
    Electrical Engineering, Electronic Engineering, Information Engineering
    Research subject
    Engineering Science with specialization in Science of Electricity
    Identifiers
    urn:nbn:se:uu:diva-176990 (URN)10.5402/2012/489379 (DOI)
    Available from: 2012-06-29 Created: 2012-06-29 Last updated: 2013-03-22Bibliographically approved
    6. A Design Study of Marine Current Turbine-Generator Combinations
    Open this publication in new window or tab >>A Design Study of Marine Current Turbine-Generator Combinations
    2009 (English)In: Ocean, Offshore and Arctic Engineering (OMAE 2009), Honolulu, Hawaii., 2009Conference paper, Published paper (Refereed)
    Place, publisher, year, edition, pages
    Honolulu, Hawaii.: , 2009
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:uu:diva-113287 (URN)
    Conference
    Ocean, Offshore and Arctic Engineering (OMAE 2009)
    Available from: 2010-01-26 Created: 2010-01-26 Last updated: 2016-04-14
    7. Design of an experimental setup for hydro-kinetic energy conversion
    Open this publication in new window or tab >>Design of an experimental setup for hydro-kinetic energy conversion
    Show others...
    2009 (English)In: International Journal on Hydropower & Dams, ISSN 1352-2523, Vol. 16, no 5, p. 112-116Article in journal (Refereed) Published
    Abstract [en]

    A hydro-kinetic energy project has been underway in Sweden since 2000, and an in-stream prototype setup for experiments at a site in a Swedish river is now in progress. The system comprises a vertical axis turbine and a directly driven permanent magnet generator. Methods and choices used in designing the system are described here. The turbine and generator are evaluated based on measurements and CFD simulations of conditions at the site for the experimental setup.

    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:uu:diva-113145 (URN)1352-2523 (ISBN)
    Available from: 2010-01-25 Created: 2010-01-25 Last updated: 2016-04-14Bibliographically approved
    8. The Söderfors Project: Construction of an Experimental Hydrokinetic Power Station
    Open this publication in new window or tab >>The Söderfors Project: Construction of an Experimental Hydrokinetic Power Station
    Show others...
    2011 (English)In: Proceedings of the 9th European Wave and Tidal Energy Conference, Southampton, UK, 5-9 September 2011, 2011Conference paper, Published paper (Refereed)
    Abstract [en]

    The Division of Electricity at Uppsala Universityis developing an experimental hydrokinetic power station for instreamexperiments at a site in a river. The purpose of this paperis to present some of the design choices made in the constructionof the experimental station. For background purposes, an outlineof the research project as a whole is also given.

    The experimental station will be deployed in the Dal¨alvenRiver at S¨oderfors, whence the project derives its name. Thesite was selected based on several technical and non-technicalreasons. The system comprises a vertically oriented cross-streamaxis turbine and a directly driven permanent magnet generator tobe situated on the riverbed. The necessary power electronics forcontrol and power conversion will be housed in a small measuringstation on shore.

    The paper discusses several aspects of the project, thatmight be of interest to other researchers in the field. Variousdesign choices, where different properties become the limiting ordeciding factor in different cases, are discussed along with theirrespective advantages and disadvantages. A brief outlook as tothe future of the project is also given.

    Keywords
    hydrokinetic energy, vertical axis turbine, lowspeed generator, experimental facility
    National Category
    Engineering and Technology
    Research subject
    Engineering Science with specialization in Science of Electricity
    Identifiers
    urn:nbn:se:uu:diva-164282 (URN)
    Conference
    9th European Wave and Tidal Energy Conference, Southampton, UK, 5-9 September 2011
    Available from: 2011-12-19 Created: 2011-12-19 Last updated: 2016-04-12
    9. Implementation of control system for hydro-kinetic energy converter
    Open this publication in new window or tab >>Implementation of control system for hydro-kinetic energy converter
    (English)In: Journal of Control Science and Engineering, ISSN 1687-5249, E-ISSN 1687-5257Article in journal (Refereed) Submitted
    National Category
    Energy Systems Other Electrical Engineering, Electronic Engineering, Information Engineering Control Engineering
    Identifiers
    urn:nbn:se:uu:diva-181554 (URN)
    Available from: 2012-09-26 Created: 2012-09-26 Last updated: 2017-12-07Bibliographically approved
    10. Dynamic stability of an electricity generation system based on renewable energy
    Open this publication in new window or tab >>Dynamic stability of an electricity generation system based on renewable energy
    Show others...
    2011 (English)In: Proceedings of CIRED 2011 - the 21st International Conference and Exhibition on Electricity Distribution, CIRED - Congrès International des Réseaux Electriques de Distribution, 2011, p. 0940-Conference paper, Published paper (Refereed)
    Abstract [en]

    Renewable energy must be stored in order to make itreliable. Flywheels are capable of storing high amounts ofenergy and can also be used as power buffers, due to theirhigh power densities. This paper investigates a way tosmooth the power output from renewable energy converters(wave, wind and marine current) by adding a doublewoundflywheel energy storage to the system. Simulationsshow that a ramp-controlled flywheel energy storage woulddrastically smooth the short time power from a wave energyconverter but not be that appropriate for longer termenergy storage. The power quality enhancement producedby the addition of the flywheel to the system is alsosimulated and discussed.

    Place, publisher, year, edition, pages
    CIRED - Congrès International des Réseaux Electriques de Distribution, 2011
    National Category
    Engineering and Technology
    Research subject
    Engineering Science with specialization in Science of Electricity
    Identifiers
    urn:nbn:se:uu:diva-157071 (URN)
    Conference
    CIRED 2011 - 21st International Conference and Exhibition on Electricity Distribution, June 6-9, Frankfurt am Main, Germany
    Available from: 2011-08-15 Created: 2011-08-15 Last updated: 2018-05-30
  • 246904.
    Yuen, Katarina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Apelfröjd, Senad
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Leijon, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Implementation of Control System for Hydrokinetic Energy Converter2013In: Journal of Control Science and Engineering, Vol. 2013, p. 10-Article in journal (Refereed)
    Abstract [en]

    At Uppsala University, a research group is investigating a system for converting the power in freely flowing water using a vertical-axis turbine directly connected to a permanent magnet generator. An experimental setup comprising a turbine, a generator, and a control system has been constructed and will be deployed in the Dalälven river in the town of Söderfors in Sweden. The design, construction, simulations, and laboratory tests of the control system are presented in this paper. The control system includes a startup sequence for the turbine and load control. These functions have performed satisfactorily in laboratory tests. Simulations of the system show that the power output is not maximized at the same tip-speed ratio as that which maximizes the turbine power capture.

  • 246905.
    Yuen, Katarina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Apelfröjd, Senad
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Leijon, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Implementation of control system for hydro-kinetic energy converterIn: Journal of Control Science and Engineering, ISSN 1687-5249, E-ISSN 1687-5257Article in journal (Refereed)
  • 246906.
    Yuen, Katarina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Lundin, Staffan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Grabbe, Mårten
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Lalander, Emilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Goude, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Leijon, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    The Söderfors Project: Construction of an Experimental Hydrokinetic Power Station2011In: Proceedings of the 9th European Wave and Tidal Energy Conference, Southampton, UK, 5-9 September 2011, 2011Conference paper (Refereed)
    Abstract [en]

    The Division of Electricity at Uppsala Universityis developing an experimental hydrokinetic power station for instreamexperiments at a site in a river. The purpose of this paperis to present some of the design choices made in the constructionof the experimental station. For background purposes, an outlineof the research project as a whole is also given.

    The experimental station will be deployed in the Dal¨alvenRiver at S¨oderfors, whence the project derives its name. Thesite was selected based on several technical and non-technicalreasons. The system comprises a vertically oriented cross-streamaxis turbine and a directly driven permanent magnet generator tobe situated on the riverbed. The necessary power electronics forcontrol and power conversion will be housed in a small measuringstation on shore.

    The paper discusses several aspects of the project, thatmight be of interest to other researchers in the field. Variousdesign choices, where different properties become the limiting ordeciding factor in different cases, are discussed along with theirrespective advantages and disadvantages. A brief outlook as tothe future of the project is also given.

  • 246907.
    Yuen, Katarina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Nilsson, Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Grabbe, Mårten
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Leijon, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Experimental setup: Low speed permanent magnet generator for marine current power conversion2007In: Proceedings of the 26th International Conference on Offshore Mechanics and Arctic Engineering, Vol 5, 2007, p. 459-462Conference paper (Refereed)
    Abstract [en]

    Marine currents, e.g. tidal currents, ocean currents and unregulated water courses are characterized by a fairly steady or regular flow and pose a significant potential for electricity generation. An ongoing research project at Uppsala University is looking into an energy conversion system with a vertical axis turbine and a permanent magnet direct drive generator placed directly in the water flow, i.e. without using a dam. This choice of technology is intended to provide a simple and robust system with low maintenance needs and minimal environmental impact. During 2006 an experimental setup has been built. It consists of a frequency converter, a motor and a gearbox to drive the generator, the generator itself, and a resistive load to consume the generated power. The generator is two meters in diameter and is built on an elevated structure over the motor and gearbox. A stainless steel structure supports the cable wound stator. The permanent NdFeB magnets are fastened in milled grooves in the rotor. The experimental setup will be used for verification of a simulation and optimization program.

  • 246908.
    Yuen, Katarina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Thomas, Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Grabbe, Mårten
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Deglaire, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bouquerel, Mathias
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Österberg, David
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Leijon, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Matching a permanent magnet synchronous generator to a fixed pitch vertical axis turbine for marine current energy conversion2009In: IEEE Journal of Oceanic Engineering, ISSN 0364-9059, E-ISSN 1558-1691, Vol. 34, no 1, p. 24-31Article in journal (Refereed)
    Abstract [en]

    Extracting energy from a free-flow marine current using a vertical axis fixed pitch turbine requires a generator that can handle varying speeds and loads, since such a turbine gives maximum power capture for a fixed tip speed ratio. A prototype of such a generator has been designed and constructed. In this paper, its variable speed and load operation is evaluated, both in terms of how the constructed generator performs in relation to simulations, and in terms of how the generator could perform with three different fixed pitch turbines. Measurements of root mean square (RMS) voltage and current differ 10% from simulations. Performance analysis with example turbines shows that the generator can match fixed tip speed ratio operation of several turbines for current speeds between 0.5 and 2.5 m/s.

  • 246909. Yuen, Kevin C J
    et al.
    Koltowska-Häggström, Maria
    Cook, David M
    Fox, Janet L
    Jönsson, Peter J
    Geffner, Mitchell E
    Abs, Roger
    Primary treatment regimen and diabetes insipidus as predictors of health outcomes in adults with childhood-onset craniopharyngioma.2014In: Journal of Clinical Endocrinology and Metabolism, ISSN 0021-972X, E-ISSN 1945-7197, Vol. 99, no 4Article in journal (Refereed)
    Abstract [en]

    CONTEXT: Craniopharyngiomas are often associated with significant morbidity due to their location and treatment effects. Little is known of the effects of primary treatment regimen and diabetes insipidus (DI), a clinical surrogate of hypothalamic obesity, on health outcomes in adults with childhood-onset craniopharyngioma (COCP).

    OBJECTIVE: The objective of the study was to examine health outcomes of adults with COCP based on primary treatment regimens and the presence of DI.

    DESIGN: This study included a retrospective KIMS (Pfizer International Metabolic Database) data analysis of 180 adults with COCP according to the primary treatment regimen [one surgery (1Surg) vs complex treatment regimen (CTrR) of more than 1Surg and/or radiotherapy] and the presence of DI.

    RESULTS: The majority of COCP patients underwent transcranial surgery (77%) without receiving radiotherapy (84%). Compared with the 1Surg group, more CTrR patients developed visual field defects and ophthalmoplegia (all P < .01). Compared with patients without DI, those with DI had higher rates of anterior pituitary hormone deficits, body mass index, and fat mass (all P < .01). By contrast, fasting glucose, hemoglobin A1c, lipid panel, and quality of life were comparable among 1Surg vs CTrR patients, and patients with vs without DI. Regardless of primary treatment received, the presence of DI in either group was associated with higher rates of anterior pituitary hormone deficits and obesity.

    CONCLUSION: CTrR and DI predicted health outcomes differently. CTrR predisposed to the development of visual dysfunction, whereas DI was associated with higher rates of anterior pituitary dysfunction and weight gain. Higher body mass index and fat mass in patients with DI further implicate the role of hypothalamic damage as an important causal factor of obesity in these patients.

  • 246910. Yuen, Pikkei
    Pushing the limits of antibioticsusceptibility testing: - an image analysis approach2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 246911. Yuille, Martin
    et al.
    van Ommen, Gert-Jan
    Bréchot, Christian
    Cambon-Thomsen, Anne
    Dagher, Georges
    Landegren, Ulf
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Genetics and Pathology.
    Litton, Jan-Eric
    Pasterk, Markus
    Peltonen, Leena
    Taussig, Mike
    Wichmann, H-Erich
    Zatloukal, Kurt
    Biobanking for Europe2008In: Briefings in Bioinformatics, ISSN 1467-5463, E-ISSN 1477-4054, Vol. 9, no 1, p. 14-24Article in journal (Other academic)
    Abstract [en]

    Biobanks are well-organized resources comprising biological samples and associated information that are accessible to scientific investigation. Across Europe, millions of samples with related data are held in different types of collections. While individual collections can be well organized and accessible, the resources are subject to fragmentation, insecurity of funding and incompleteness. To address these issues, a Biobanking and BioMolecular Resources Infrastructure (BBMRI) is to be developed across Europe, thereby implementing a European roadmap for research infrastructures that was developed by a forum of EU member states and that has been received by the European Commission. In this review, we describe the work involved in preparing for the construction of BBMRI in a European and global context.

  • 246912. Yukote, K
    et al.
    Mori, S
    Siegbahn, A
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Medical Sciences.
    Ronnstrand, L
    Wernstedt, C
    Heldin, C-H
    Claesson-Welsh, L
    Structural determinants in the Platelet-derived Growth Factor alfa-receptor implicated in modulation of chemotaxis1996In: J Biol Chem, Vol. 9, p. 5101-Article in journal (Refereed)
  • 246913. Yuksel, Muhammed
    et al.
    Laukens, Debby
    Heindryckx, Femke
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Van Vlierberghe, Hans
    Geerts, Anja
    Wong, F. Susan
    Wen, Li
    Colle, Isabelle
    Hepatitis mouse models: from acute-to-chronic autoimmune hepatitis2014In: International journal of experimental pathology (Print), ISSN 0959-9673, E-ISSN 1365-2613, Vol. 95, no 5, p. 309-320Article, review/survey (Refereed)
    Abstract [en]

    Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease associated with interface hepatitis, raised plasma liver enzymes, the presence of autoantibodies and regulatory T-cell (Tregs) dysfunction. The clinical course is heterogeneous, manifested by a fulminant or indolent course. Although genetic predisposition is well accepted, the combination with currently undefined environmental factors is crucial for the development of the disease. Progress in the development of reliable animal models provides added understanding of the pathophysiology of AIH, and these will be very useful in evaluating potential therapeutics. It appears that artificially breaking tolerance in the liver is easy. However, maintaining this state of tolerance breakdown, to get chronic hepatitis, is difficult because liver immune homeostasis is strongly regulated by several immune response inhibitory mechanisms. For example, Tregs are crucial regulators in acute and chronic hepatitis, and C57BL/6 mice are most prone to experimental AIH. Immunization of C57BL/6 mice with liver (AIH) autoantigens (CYP2D6/FTCD or IL-4R) and the disturbance of liver regulatory mechanism(s), leading to experimental AIH, are likely to be most representative of human AIH pathology.

  • 246914.
    Yuksel, Onur
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Social Sciences, Department of Informatics and Media.
    A Sound-Based Intervention for The Artistic Encounter2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Art experience, as an important contributor to intellectual experiences, has been studied by many researchers and philosophers to unearth and enhance certain qualities of it [9,16,21,22]. One of the ways of interpreting profound forms of art experience has been relating it with “flow,” a term that indicates a holistic sensation with the act of total involvement, concentration, intrinsic enjoyment and action-awareness [7]. Previous studies argue that looking at art experience as a form of flow, reveals its structural characteristics and dynamics more clearly, and thereby discuss art experience as a flow-conductive activity [8]. Along with that, the flow phenomenon has been studied in the context of musical activities and argued to have strong links with the musical domain [3,5]. Little is known at the moment about how musical sound can facilitate flow in the context of an art experience. This study presents a research through sound design process, with the purpose of facilitating an enhanced art experience i.e., facilitating flow in the artistic encounter. The study presents two primary contributions: (1) a presentation of the design process, consisting of an explorative prestudy at Moderna Museet in Stockholm, a followup sound experiment in an artistic encounter and (2) findings from the evaluation at Uppsala Konstmuseum, focused on identifying the impact that the designed sound artefact has had on individuals’ experiences. The author argues that the sound artefact may create an immersive environment, help initiate the mindset for introspection through the interactive characteristics and elevate conditions for flow to an observable extent. Lastly, critical reflections on the design process are also included in the final chapter to benefit research through sound design community.

  • 246915.
    Yuksel, Tansu
    et al.
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Social Sciences, Department of Business Studies.
    Persson, Elin
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Social Sciences, Department of Business Studies.
    Preferensaktier: Påverkas ett bolags börsvärde när de offentliggör en preferensaktieemission?2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    I samband med lågkonjunkturen 2008 har det skett en ökning av preferensaktieemissioner på den svenska marknaden. Då detta är ett relativt nytt fenomen på den svenska börsen har få studier genomförts om hur bolagets börsvärde påverkas av offentliggörandet av en preferensaktieemission. För att undersöka hur börsvärdet förändras genomför vi en eventstudie där vi testar den svenska marknadens effektivitet vid offentliggörandena. Vi studerar om det uppkommer avvikelseavkastningar i samband med offentliggörandet av bolagens beslut. Dagen för offentliggörandet visar resultatet i vår studie en genomsnittlig negativ signifikant reaktion med 1,25 %. Dagen efter offentliggörandet finner vi positiva signifikanta avvikelseavkastningar vilket indikerar att marknaden är ineffektiv och att bolagets börsvärde efter offentliggörandet påverkas positivt.

  • 246916.
    Yuldashev, Sh. U.
    et al.
    Dongguk University, Nano-Information Technology Academy (NITA).
    Yunusov, Z. A.
    Dongguk University, Nano-Information Technology Academy (NITA).
    Kwon, Y. H.
    Dongguk University, Quantum-Functional Semiconductor Research Center.
    Lee, S. H.
    Korea University, Department of Physics.
    Ahuja, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Kang, T. W.
    Dongguk University, Nano-Information Technology Academy (NITA).
    Critical behavior of the resistivity of GaMnAs near the Curie temperature2017In: Solid State Communications, ISSN 0038-1098, E-ISSN 1879-2766, Vol. 263, p. 38-41Article in journal (Refereed)
    Abstract [en]

    The effect of the magnetization fluctuations on the resistivity of GaMnAs near the Curie temperature T-C was experimentally studied. It is shown that the determination of T-C from the maximum of the temperature derivative of the resistivity is valid for the samples with a high concentration of free carries. Whereas, for the samples with low concentration of free carriers the T-C coincides with the resistivity maximum. The magnetic specific heat for T > T-C demonstrates the crossover from the one dimensional to the three dimensional critical behavior when the temperature become closer to the Curie temperature. This is explained by the formation of the ferromagnetic phase in the paramagnetic side of the phase transition which is started from Mn-Mn dimers oriented along one direction.

  • 246917.
    Yumin, Xiao
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Social Sciences, Department of Statistics.
    Robustness of the Likelihood Ratio Test for Periodicity in Short Time Series and Application to Gene Expression Data2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 246918.
    YUN, H
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    LEE, ML
    MARKIDES, KE
    CHARCOAL POROUS LAYER OPEN-TUBULAR COLUMN GAS-CHROMATOGRAPHY FOR PERMANENT GAS-ANALYSIS1995In: JOURNAL OF MICROCOLUMN SEPARATIONS, ISSN 1040-7685, Vol. 7, no 3, p. 207-212Article in journal (Refereed)
    Abstract [en]

    The preparation of charcoal porous layer open tabular (PLOT) columns, and their application to the separation of permanent gases and light hydrocarbons are reported. Two types of charcoal, coconut and darco charcoal, were used to prepare columns from fus

  • 246919. Yun, Sining
    et al.
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Ma, Tingli
    Pt-Free Counter Electrode for Dye-Sensitized Solar Cells with High Efficiency2014In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 26, no 36, p. 6210-6237Article in journal (Refereed)
    Abstract [en]

    Dye-sensitized solar cells (DSSCs) have attracted widespread attention in recent years as potential cost-effective alternatives to silicon-based and thin-film solar cells. Within typical DSSCs, the counter electrode (CE) is vital to collect electrons from the external circuit and catalyze the I-3(-) reduction in the electrolyte. Careful design of the CEs can improve the catalytic activity and chemical stability associated with the liquid redox electrolyte used in most cells. In this Progress Report, advances made by our groups in the development of CEs for DSSCs are reviewed, highlighting important contributions that promise low-cost, efficient, and robust DSSC systems. Specifically, we focus on the design of novel Pt-free CE catalytic materials, including design ideas, fabrication approaches, characterization techniques, first-principle density functional theory (DFT) calculations, ab-initio Car-Parrinello molecular dynamics (CPMD) simulations, and stability evaluations, that serve as practical alternatives to conventional noble metal Pt electrodes. We stress the merits and demerits of well-designed Pt-free CEs, such as carbon materials, conductive polymers, transition metal compounds (TMCs) and their corresponding hybrids. Also, the prospects and challenges of alternative Pt catalysts for their applications in new-type DSSCs and other catalytic fields are discussed.

  • 246920. Yun, Sining
    et al.
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Ma, Tingli
    Superior Catalytic Activity of Sub-5 mu m-Thick Pt/SiC Films as Counter Electrodes for Dye-Sensitized Solar Cells2014In: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 6, no 6, p. 1584-1588Article in journal (Refereed)
    Abstract [en]

    Dye-sensitized solar cells with sub-5 mu m-thick Pt/SiC-P (1.79 at.% Pt), Pt/SiC-M (0.45 at.% Pt), and Pt/SiC-R (0.39 at.% Pt) counter electrode (CE) films fabricated by using three different processes produced power conversion efficiencies of 6.82, 7.64, and 7.04% that reached 86.5, 97.0, and 89.3 %, respectively, of the level obtained by using a print-Pt CE (7.88 %). These materials can reduce the cost of CEs and solve challenges involving Pt.

  • 246921. Yun, Sining
    et al.
    Pu, Haihui
    Chen, Junhong
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Ma, Tingli
    Enhanced Performance of Supported HfO2 Counter Electrodes for Redox Couples Used in Dye-Sensitized Solar Cells2014In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 7, no 2, p. 442-450Article in journal (Refereed)
    Abstract [en]

    Mesoporous-graphitic-carbon-supported HfO2 (HfO2-MGC) nanohybrids were synthesized by using a soft-template route. Characterization and a systematic investigation of the catalytic properties, stability, and catalytic mechanism were performed for HfO2-MGC counter electrodes (CEs) in dye-sensitized solar cells (DSSCs). The new HfO2-MGC as a CE in DSSCs showed a surprisingly high efficiency of 7.75% for the triiodide/iodide redox couple and 3.69% for the disulfide/thiolate redox couple, greater than the Pt electrode in the corresponding electrolyte system, which opens up a possibility for its practical application.

  • 246922. Yun, Sining
    et al.
    Wu, Mingxing
    Wang, Yudi
    Shi, Jing
    Lin, Xiao
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Ma, Tingli
    Pt-like Behavior of High-Performance Counter Electrodes Prepared from Binary Tantalum Compounds Showing High Electrocatalytic Activity for Dye-Sensitized Solar Cells2013In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 6, no 3, p. 411-416Article in journal (Refereed)
  • 246923. Yun, Sining
    et al.
    Zhang, Hong
    Pu, Huihai
    Chen, Junhong
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Ma, Tingli
    Metal Oxide/Carbide/Carbon Nanocomposites: In Situ Synthesis, Characterization, Calculation, and their Application as an Efficient Counter Electrode Catalyst for Dye-Sensitized Solar Cells2013In: Advanced Engergy Materials, ISSN 1614-6832, Vol. 3, no 11, p. 1407-1412Article in journal (Refereed)
  • 246924.
    Yun, Y.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Rusz, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Suzuki, M. -T
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Oppeneer, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    First-principles investigation of higher oxides of uranium and neptunium: U3O8 and Np2O52011In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 83, no 7, p. 075109-Article in journal (Refereed)
    Abstract [en]

    A computational study is presented of the structural, electronic, and magnetic properties of U3O8 and Np2O5, which are actinide oxides in a higher oxidation state than the tetravalent state of the common dioxide phases, UO2 and NpO2. The calculations are based on the density functional theory +U approach, in which additional Coulomb correlations on the actinide atom are taken into account. The calculated properties of these two higher oxidized actinide oxides are analyzed and compared to those of their tetravalent analogs. The optimized structural parameters of these noncubic oxides are found to be in reasonable agreement with available experimental data. U3O8 is predicted to be a magnetic insulator, having one U atom in a hexavalent oxidation state and two U atoms in a pentavalent oxidation state. For Np2O5, which is also predicted to be an insulator, a complicated noncollinear magnetic structure is computed, leading to a nonzero overall magnetization with a slight antiferromagnetic canting. The calculated electronic structures are presented and the variation of the U 5f or Np 5f-O 2p hybridization with the oxidation state is analyzed. With increasing oxygen content, the nearly localized 5f electrons of the actinide elements are more positioned near the Fermi level and the hybridization between 5f and 2p states is markedly increased.

  • 246925.
    Yun, Younsuk
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science.
    Eriksson, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science.
    Oppeneer, Peter M.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science.
    First-principles modeling of He-clusters in UO22009In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 385, no 1, p. 72-74Article in journal (Refereed)
    Abstract [en]

    We have investigated the behavior of He in UO2, Using the projector-augmented-wave (PAW) method and the generalized gradient approximation (GGA) based on the density functional theory. Total energy calculations with atomic relaxation included have been performed in a 96-atom large supercell. We have found that He has a strong tendency to form a cluster in vicinity of an octahedral interstitial site (OIS) in the UO2 matrix. In addition, the strain energy produced by a He-cluster was found to be sufficient to create point defects of the host atoms in UO2. Our study suggests that He-clusters and He-induced point defects play an important role for the local mechanical properties Of UO2 (C) 2008 Elsevier B.V. All rights reserved.

  • 246926.
    Yun, Younsuk
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science.
    Eriksson, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science.
    Oppeneer, Peter M.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science.
    Theory of He trapping, diffusion, and clustering in UO22009In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 385, no 3, p. 510-516Article in journal (Refereed)
    Abstract [en]

    We have performed ab initio total energy calculations to investigate the behavior of helium and its diffusion properties in uranium dioxide MOD. Our investigations are based on the density functional theory within the generalized gradient approximation (GGA). The trapping behavior of He in UO2 has been modeled with a supercell containing 96-atoms as well as uranium and oxygen vacancy trapping sites. The calculated incorporation energies show that for He a uranium vacancy is more stable than an oxygen vacancy or an octahedral interstitial site (OIS). Interstitial site hopping is found to be the rate-determining mechanism of the He diffusion process and the corresponding migration energy is computed as 2.79 eV at 0 K (with the spin-orbit coupling (SOC) included), and as 2.09 eV by using the thermally expanded lattice parameter of UO2 at 1200 K, which is relatively close to the experimental value of 2.0 eV. The lattice expansion coefficient of He-induced swelling of UO2 is calculated as 9 x 10(-2). For two He atoms, we have found that they form a dumbbell configuration if they are close enough to each other, and that the lattice expansion induced by a dumbbell is larger than by two distant interstitial He atoms. The clustering tendency of He has been studied for small clusters of up to six He atoms. We find that He strongly tends to cluster in the vicinity of an OIS, and that the collective action of the He atoms is sufficient to spontaneously create additional point defects around the He cluster in the UO2 lattice. (C) 2008 Elsevier B.V. All rights reserved.

  • 246927.
    Yun, Younsuk
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science.
    Eriksson, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science.
    Oppeneer, Peter M.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science.
    Kim, Hanchul
    Park, Kwangheon
    First-principles theory for helium and xenon diffusion in uranium dioxide2009In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 385, no 2, p. 364-367Article in journal (Refereed)
    Abstract [en]

    The diffusion properties of He and Xe in UO2 have been investigated, using density-functional calculations employing the projector-augmented-wave (PAW) method and the generalized gradient approximation (GGA). The migration energies corresponding to both interstitial and vacancy-assisted mechanisms have been calculated and the results for the two noble gas atoms are compared with each other. We suggest that He likely diffuses by hopping through a single vacancy with computed low migration energies smaller than 0.79 eV and its diffusivity is much higher than that of Xe. Xe has a quite large migration energy compared to He; the strain energy plays a key role in Xe diffusion in UO2.

  • 246928.
    Yun, Younsuk
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science.
    Kim, Hanchul
    Kim, Heemoon
    Park, Kwangheon
    Atomic diffusion mechanism of Xe in UO22008In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 378, no 1, p. 40-44Article in journal (Refereed)
    Abstract [en]

    We have investigated vacancy-assisted diffusion of Xe in uranium dioxide MOO calculating incorporation, binding, and migration energies. All the energy values have been obtained using the density functional theory (DFT) within the generalized gradient approximation (GGA) and the projector-augmented-wave (PAW) method. Considering spin-polarization effect, we find that the computed migration energy is reduced by and agrees well with experimental data compared to those obtained from nonmagnetic calculations. We also find that an oxygen vacancy lowers the migration energy of a uranium vacancy by about 1 eV, enhancing an effective movement of vacancy clusters consisting of both uranium and oxygen vacancies. Furthermore, the strain energy of Xe is large enough to contribute to the clustering of vacancies making it the driving force for the vacancy-assisted diffusion of Xe in UO2. In summary all the calculated results suggest that the trivacancy is a major diffusion pathway of Xe in UO2.

  • 246929.
    Yun, Younsuk
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Legut, Dominik
    Oppeneer, Peter M.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Phonon spectrum, thermal expansion and heat capacity of UO2 from first-principles2012In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 426, no 1-3, p. 109-114Article in journal (Refereed)
    Abstract [en]

    We report first-principles calculations of the phonon dispersion spectrum, thermal expansion, and heat capacity of uranium dioxide. The so-called direct method, based on the quasiharmonic approximation, is used to calculate the phonon frequencies within a density functional framework for the electronic structure. The phonon dispersions calculated at the theoretical equilibrium volume agree well with experimental dispersions. The computed phonon density of states (DOSs) compare reasonably well with measured data, as do also the calculated frequencies of the Raman and infrared active modes including the LO/TO splitting. To study the pressure dependence of the phonon frequencies we calculate phonon dispersions for several lattice constants. Our computed phonon spectra demonstrate the opening of a gap between the optical and acoustic modes induced by pressure. Taking into account the phonon contribution to the total free energy of UO2 its thermal expansion coefficient and heat capacity have been computed from first-principles. Both quantities are in good agreement with available experimental data for temperatures up to about 500 K. 

  • 246930. Yun, Younsuk
    et al.
    Oppeneer, Peter M.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    First-principles design of next-generation nuclear fuels2011In: MRS bulletin, ISSN 0883-7694, E-ISSN 1938-1425, Vol. 36, no 3, p. 178-184Article in journal (Refereed)
    Abstract [en]

    The behavior of nuclear fuel in a reactor is a complex phenomenon that is influenced by a large number of materials properties, which include thermomechanical strength, chemical stability, microstructure, and defects. As a consequence, a comprehensive understanding of the fuel material behavior presents a significant modeling challenge, which must be mastered to improve the efficiency and reliability of current nuclear reactors. It is also essential to the development of advanced fuel materials for next-generation reactors. Over the last two decades, the use of density functional theory (DFT) has greatly contributed to our understanding by providing profound information on nuclear fuel materials, ranging from fundamental properties of f-electron systems to thermomechanical materials properties. This article briefly summarizes the main achievements of this first-principles computational methodology as it applies to nuclear fuel materials. Also, the current status of first-principles modeling is discussed, considering existing limitations and drawbacks such as size limitation and the added complexity associated with high temperature analysis. Finally, the future role of DFT modeling in the nuclear fuels industry is put into perspective.

  • 246931.
    Yun, Younsuk
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science.
    Oppeneer, Peter M.
    Kim, Hanchul
    Park, Kwangheon
    Defect energetics and Xe diffusion in UO2 and ThO22009In: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 57, no 5, p. 1655-1659Article in journal (Refereed)
    Abstract [en]

    We have performed ab initio total energy calculations to investigate the defect energetics and diffusion behavior of Xe in UO2 and ThO2 matrices. All calculations have been carried out Using density functional theory within the generalized gradient approximation and applying the projector-augmented-wave method. Our results Show that the formation and migration energies of vacancy defects are more than twice as high in ThO2 compared with UO2. Another notable difference between the two oxides is the role played by an oxygen vacancy ill the movement of a cation vacancy. An vacancy enhances the movement Of a uranium vacancy by lowering its migration energy by about 1 eV, but a similar effect is not observed in ThO2. The different behavior of cation vacancies in the two oxides strongly affects the mobility of fission gases and leads to differences in their respective diffusion behavior. We sui, est that the strong resistance against oxidation of ThO2 prevents the creation and migration of defects. and results ill a lower mobility of fission gases ill ThO2 as compared to UO2.

  • 246932. Yun, Zhihong
    et al.
    Hu, Lijuan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Clinical Virology.
    Forsman, Anna
    Uzhameckis, Dmitrijs
    Jern, Patric
    Yolken, Robert
    Torrey, R Fuller
    Blomberg, Jonas
    Individual pattern of RNA expression of human endogenous gammaretrovirus-like sequences in the human brainManuscript (Other academic)
  • 246933.
    Yung, Der-Liang
    et al.
    Tallinn Univ Technol, Dept Mech Engn, EE-19086 Tallinn, Estonia..
    Antonov, Maksim
    Tallinn Univ Technol, Dept Mech Engn, EE-19086 Tallinn, Estonia..
    Hussainova, Irina
    Tallinn Univ Technol, Dept Mech Engn, EE-19086 Tallinn, Estonia..
    Veinthal, Renno
    Tallinn Univ Technol, Dept Mech Engn, EE-19086 Tallinn, Estonia..
    Hogmark, Sture
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Composition And Structure Of Bimodal WC-Co Materials Related To Mechanical Properties And Abrasive Wear2015In: M2D2015: Proceedings Of The 6Th International Conference On Mechanics And Materials In Design, 2015, p. 655-664Conference paper (Refereed)
    Abstract [en]

    This study performs the comprehensive analysis with regards to the amount of ultrafine WC grains needed for the appropriate reinforcement of the metallic binder in WC-8Co cemented carbides. The ratio of coarse versus ultrafine WC grains in the bimodal system is examined. The goal is to investigate the balance of grain distribution to achieve overall improvement of the material's mechanical and wear properties.

  • 246934. Yung, Hong Wa
    et al.
    Atkinson, Daniel
    Campion-Smith, Tim
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Women's and Children's Health.
    Olovsson, Matts
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Women's and Children's Health, Obstetrics and Gynaecology.
    Charnock-Jones, D. Stephen
    Burton, Graham J.
    Differential activation of placental unfolded protein response pathways implies heterogeneity in causation of early- and late-onset pre-eclampsia2014In: Journal of Pathology, ISSN 0022-3417, E-ISSN 1096-9896, Vol. 234, no 2, p. 262-276Article in journal (Refereed)
    Abstract [en]

    Based on gestational age at diagnosis and/or delivery, pre-eclampsia (PE) is commonly divided into early-onset (<34 weeks) and late-onset (>= 34 weeks) forms. Recently, the distinction between 'placental' and 'maternal' causation has been proposed, with 'placental' cases being more frequently associated with early-onset and intrauterine growth restriction. To test whether molecular placental pathology varies according to clinical presentation, we investigated stress-signalling pathways, including unfolded protein response (UPR) pathways, MAPK stress pathways, heat-shock proteins and AMPK.. in placentae delivered by caesarean section for clinical indications at different gestational ages. Controls included second-trimester, pre-term and normal-term placentae. BeWo cells were used to investigate how these pathways react to different severities of hypoxia-reoxygenation (H/R) and pro-inflammatory cytokines. Activation of placental UPR and stress-response pathways, including P-IRE1 alpha, ATF6, XBP-1, GRP78 and GRP94, P-p38/p38 and HSP70, was higher in early-onset PE than in both late-onset PE and normotensive controls (NTCs), with a clear inflection around 34 weeks. Placentae from >= 34 weeks PE and NTC were indistinguishable. Levels of UPR signalling were similar between second-trimester and term controls, but were significantly higher in pre-term 'controls' delivered vaginally for chorioamnionitis and other conditions. Severe H/R (1/20% O-2) induced equivalent activation of UPR pathways, including P-eIF2 alpha, ATF6, P-IRE1 alpha, GRP78 and GRP94, in BeWo cells. By contrast, the pro-inflammatory cytokines TNF alpha and IL-1 beta induced only mild activation of P-eIF2 alpha and GRP78. AKT, a central regulator of cell proliferation, was reduced in the <34 weeks PE placentae and severe H/R-treated cells, but not in other conditions. These findings provide the first molecular evidence that placental stress may contribute to the pathophysiology of early-onset pre-eclampsia, whereas that is unlikely to be the case in the late-onset form of the syndrome. (c) 2014 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

  • 246935. Yung, Hong Wa
    et al.
    Atkinson, Daniel
    Olovsson, Matts
    Burton, Graham
    Molecular Evidence That Placental Pathology is More Severe in Early-Onset Compared to Late-Onset Pre-Eclampsia2012In: Placenta, ISSN 0143-4004, E-ISSN 1532-3102, Vol. 33, no 9, p. A84-A84Article in journal (Other academic)
  • 246936. Yung, Hong Wa
    et al.
    Campion-Smith, Tim
    Olovsson, Matts
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Women's and Children's Health, Obstetrics and Gynaecology.
    Burton, Graham
    Cell-Type Specific Activation of Unfolded Protein Response Pathways in Pre-Eclamptic Placentas2012In: Placenta, ISSN 0143-4004, E-ISSN 1532-3102, Vol. 33, no 9, p. A85-A85Article in journal (Other academic)
  • 246937. Yung, Hong Wa
    et al.
    Colleoni, Francesca
    Olovsson, Matts
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Women's and Children's Health, Obstetrics and Gynaecology.
    Kingdom, John
    Burton, Graham
    Placental Energy Depletion In Early-Onset Preeclanipsia: Role Of EIF2 Alpha Signalling In Mitochondrial Activity2013In: Placenta, ISSN 0143-4004, E-ISSN 1532-3102, Vol. 34, no 9, p. A85-A85Article in journal (Other academic)
  • 246938. Yung, Hong Wa
    et al.
    Olovsson, Matts
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Women's and Children's Health, Obstetrics and Gynaecology.
    Charnock-Jones, Steve
    Burton, Graham
    Placental Endoplasmic Reticulum (ER) Stress as a Novel Molecular Signature to Distinguish Subtypes of Pre-Eclampsia2014In: Reproductive Sciences, ISSN 1933-7191, E-ISSN 1933-7205, Vol. 21, no 3S, p. 405A-406AArticle in journal (Other academic)
  • 246939.
    Yunus, S.M. , A.K. Azad, S.-G. Eriksson, J. Eriksen, H.Rundlöf
    Uppsala University, Interfaculty Units, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, The Studsvik Neutron Research Laboratory.
    Temperature dependent magnetic characterization of the spinel system GaxCoFe1-xCrO4 (0 £ x £ 1) by neutron powder diffraction at the range 10K to 500K2003In: Physica B, Vol. 337, p. 323-Article in journal (Other scientific)
  • 246940. Yus-Díez, Jesús
    et al.
    Udina, Mireia
    Soler, Maria Rosa
    Lothon, Marie
    Nilsson, Erik
    Bech, Joan
    Sun, Jielun
    Nocturnal boundary layer turbulence regimes analysis during the BLLAST campaign2019In: Atmospheric Chemistry And Physics, Vol. 19, p. 9495-9514Article in journal (Refereed)
    Abstract [en]

    A night-time turbulence regime classification, the so-called “HOckey-Stick Transition ” (HOST) theory, proposed by Sun et al. (2012) from the Cooperative Atmosphere–Surface Exchange Study-1999 (CASES-99) is explored using data from the Boundary-Layer Late Afternoon and Sunset Turbulence (BLLAST) field campaign which took place during summer 2011 in the central French Pyrenean foothills. Results show that the HOST turbulence relationships for the BLLAST field campaign data are strongly dependent on both the meteorological and orographic features. The HOST pattern only appears for nights when a stably stratified boundary layer can be developed, corresponding to fairweather and clear-sky nights, when the flow is generated by the nearby orography, from the south and the south-east. Those flows strongly influenced by the orography may generate intermittent or enhanced turbulence. When considering the whole nocturnal dataset for these flow directions, several enhanced turbulence points are found to be associated with sudden wind speed and directional shear transitions. In contrast, flows from other directions do not reproduce the HOST relationships and the turbulence relationship is almost linear, independent of vertical temperature gradients, corresponding to flows driven by synoptic scales. In addition we identify examples of gravity waves and top-down turbulent events that lead to transitions between the turbulence regimes.

  • 246941.
    Yusnizar, Y.
    et al.
    Bogor Agr Univ IPB, Grad Sch, Bogor 16680, Indonesia.;Swedish Univ Agr Sci SLU, Dept Anim Breeding & Genet, SE-75007 Uppsala, Sweden.;Indonesian Inst Sci LIPI, Biotechnol Res Ctr, Cibinong 16912, Indonesia..
    Wilbe, Maria
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Medicinsk genetik och genomik. Swedish Univ Agr Sci SLU, Dept Anim Breeding & Genet, SE-75007 Uppsala, Sweden..
    Herlino, A. O.
    Swedish Univ Agr Sci SLU, Dept Anim Breeding & Genet, SE-75007 Uppsala, Sweden..
    Sumantri, C.
    Bogor Agr Univ IPB, Fac Anim Sci, Dept Anim Prod & Technol, Bogor 16680, Indonesia..
    Noor, R. Rachman
    Bogor Agr Univ IPB, Fac Anim Sci, Dept Anim Prod & Technol, Bogor 16680, Indonesia..
    Boediono, A.
    Bogor Agr Univ IPB, Fac Vet Med, Dept Anat Physiol & Pharmacol, Bogor 16680, Indonesia..
    Andersson, Leif
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology. Swedish Univ Agr Sci SLU, Dept Anim Breeding & Genet, SE-75007 Uppsala, Sweden..
    Andersson, G.
    Swedish Univ Agr Sci SLU, Dept Anim Breeding & Genet, SE-75007 Uppsala, Sweden..
    Microphthalmia-associated transcription factor mutations are associated with white-spotted coat color in swamp buffalo2015In: Animal Genetics, ISSN 0268-9146, E-ISSN 1365-2052, Vol. 46, no 6, p. 676-682Article in journal (Refereed)
    Abstract [en]

    A candidate gene analysis of the microphthalmia-associated transcription factor (MITF) gene was used in an attempt to identify the genetic basis for a white-spotted coat color phenotype in the Asian swamp buffalo (Bubalus bubalis carabanensis). Ninety-three buffaloes32 solid, 38 spotted and 23 white individualswere Sanger-sequenced for all MITF exons as well as highly conserved intronic and flanking regions. MITFcDNA representing skin and iris tissue from six spotted, nine solid and one white buffaloes was also Sanger-sequenced to confirm detected mutations. Two independent loss-of-function mutations, a premature stop codon (c.328C>T, p.Arg110*) and a donor splice-site mutation (c.840+2T>A, p.Glu281_Leu282Ins8), both of which cause white-spotted coat color in swamp buffaloes, were identified. The nonsense mutation leads to a premature stop codon in exon 3, and likely removal of the resulting mRNA via nonsense-mediated decay pathway, whereas the donor splice-site mutation leads to aberrant splicing of exon 8 that encodes part of a highly conserved region of MITF. The resulting insertion of eight amino acid residues is expected to perturb the leucine zipper part in the basic helix-loop-helix leucine zipper (bHLH-Zip) domain and will most likely influence dimerization and DNA binding capacity. Electrophoretic mobility shift assay was performed using mutant and wild-type MITF proteins and showed that the mutant MITF protein resulting from the splice-site mutation decreased invitro DNA binding capacity compared to wild-type MITF. White-spotted buffalo bulls are sacrificed in funeral ceremonies in Tana Toraja, Indonesia, because they are considered holy, and our results show that genetic variation causes a tie to the cultural use of these buffaloes.

  • 246942. Yusof, Siti R
    et al.
    Mohd Uzid, Mahathir
    Teh, Eng-Huat
    Hanapi, Nur Aziah
    Mohideen, Mazlin
    Mohamad Arshad, Ahmad Saifuddin
    Mordi, Mohd Nizam
    Loryan, Irena
    Uppsala University, Science for Life Laboratory, SciLifeLab.
    Margareta, Hammarlund-Udenaes
    Uppsala University, Science for Life Laboratory, SciLifeLab.
    Rate and extent of mitragynine and 7-hydroxymitragynine blood-brain barrier transport and their intra-brain distribution:: the missing link in pharmacodynamic studies2018In: Addiction Biology, ISSN 1355-6215, E-ISSN 1369-1600Article in journal (Refereed)
    Abstract [en]

    Mitragyna speciosa is reported to be beneficial for the management of chronic pain and opioid withdrawal in the evolving opioid epidemic. Data on the blood-brain barrier (BBB) transport of mitragynine and 7-hydroxymitragynine, the active compounds of the plant, are still lacking and inconclusive. Here, we present for the first time the rate and the extent of mitragynine and 7-hydroxymitragynine transport across the BBB, with an investigation of their post-BBB intra-brain distribution. We utilized an in vitro BBB model to study the rate of BBB permeation of the compounds and their interaction with efflux transporter P-glycoprotein (P-gp). Mitragynine showed higher apical-to-basolateral (A-B, i.e. blood-to-brain side) permeability than 7-hydroxymitragynine. 7-Hydroxymitragynine showed a tendency to efflux, with efflux ratio (B-A/A-B) of 1.39. Both were found to inhibit the P-gp and are also subject to efflux by the P-gp. Assessment of the extent of BBB transport in vivo in rats from unbound brain to plasma concentration ratios (Kp,uu,brain ) revealed extensive efflux of both compounds, with less than 10 percent of unbound mitragynine and 7-hydroxymitragynine in plasma crossing the BBB. By contrast, the extent of intra-brain distribution was significantly different, with mitragynine having 18-fold higher brain tissue uptake in brain slice assay compared with 7-hydroxymitragynine. Mitragynine showed a moderate capacity to accumulate inside brain parenchymal cells, while 7-hydroxymitragynine showed restricted cellular barrier transport. The presented findings from this systematic investigation of brain pharmacokinetics of mitragynine and 7-hydroxymitragynine are essential for design and interpretation of in vivo experiments aiming to establish exposure-response relationship.

  • 246943.
    Yuspeh, Emmy
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Social Sciences, Department of Social and Economic Geography.
    Havelock in India as an Emerging SCUBA Diving Destination: Challenges and Opportunities2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This qualitative field study is conducted on the Andaman Islands in India and focuses on the sustainable destination development and SCUBA diving tourism. The island in focus, Havelock, is an emerging tourist destination and an international airport is scheduled to open in the Andamans in 2021. The topic is approached through observation and interviews with people involved with the SCUBA diving industry, selected informants, and diving tourists. Different scales that operate with the island’s development - global, national, regional and local - are investigated. Global warming poses a threat to the coral reefs that is the main resource for tourism at the location and the longterm residents’ education in the subject is absent. The communication between state and nation is a problem as laws are passed without participation or awareness from the local community which makes it difficult for businessowners to invest. Furthermore, diver motivation and satisfaction are investigated. The main motivation of beginner level diving tourists from India are not educated in how the underwater world looks like, but are motivated to see what they already know through movies like “Finding Nemo”. The study reveals that a degraded coral reef does not affect diver satisfaction where the divers are not educated in how a healthy reef looks like. The local Marine Protected Area - Rani Jhansi Marine National Park - is in 2019 funded by the government and there are currently no entrance fees for diving tourists. However, this has been proved successful in other destinations. The Marine Protected Area is perceived as positive by the local SCUBA industry, but it is not interacting with its regulation and governing.

  • 246944. Yusuf, Dilmurat
    et al.
    Davis, Andrew M
    Kleywegt, Gerard J
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Structural Molecular Biology.
    Schmitt, Stefan
    An alternative method for the evaluation of docking performance: RSR vs RMSD.2008In: Journal of chemical information and modeling, ISSN 1549-9596, Vol. 48, no 7, p. 1411-1422Article in journal (Refereed)
    Abstract [en]

    A new assessment criterion for docking poses is proposed in which experimental electron density is taken into account when evaluating the ability of docking programs to reproduce experimentally observed binding modes. Three docking programs (Gold, Glide, and Fred) were used to generate poses for a set of 88 protein-ligand complexes for which the crystal structure is known. The new criterion is based on the real space R-factor (RSR), which measures how well a group of atoms-in our case the ligand-fits the experimental electron density by comparing that density to the expected density, calculated from the model (i.e., the predicted ligand pose). The RSR-based measure is compared to the traditional criterion, the root-mean-square distance (RMSD) between the docking pose and the binding configuration in the crystallographic model. The results highlight several shortcomings of the RMSD criterion that do not affect the RSR-based measure. Examples illustrate that the RSR-derived approach allows a more meaningful a posteriori assessment of docking methods and results. Practical implications for docking evaluations and for methodological development work in this field are discussed.

  • 246945.
    Yusuf, Hoodo
    et al.
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Social Sciences, Department of Informatics and Media.
    Martinez Bergström, Malin
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Social Sciences, Department of Informatics and Media.
    Creating legitimacy within blockchain startups in a virtual context: A study on how decentralized organizations raise funds before executing an Initial Coin Offering.2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Denna uppsats ämnar att undersöka de kommunikativa processer för blockedjeteknologi startups som ska lansera en så kallad “initial coin offering” och således mynta sin egna kryptovaluta, såsom till exempel bitcoin. Vi avser att undersöka det strategiska kommunikation processerna detta involverar.

    Från ena perspektivet är ett decentraliserat blockkedjesystem högt värderat på grund av det faktum att det jämställer samtliga medverkande och på så vis skapar en “perfekt demokrati”, å andra sidan argumenterar många att centralisering behövs för att bibehålla tillit. Tillit till organisationer skapas genom vetandet att det finns konsekvenser till dess handlingar som kan införas av högre auktoriteter ifall dessa handlingar faller utanför ramarna av vad som anses accepterat (De Fillipe & Wright, 2015). Utan en högre auktoritet som kan implementera detta blir tillit svårare att upprätthålla. Dock verkar blockkedjeteknologi motbevisa detta koncept. Hur är det möjligt för organisationer utan någon reglering från centrala myndigheter att skapa legitimitet och tillit för att på så sätt kunna få investeringar? Resultaten vi fann ställdes i jämförelse sig till våra tre legitimitets teorier som var kognitiv legitimitet, moral legitimitet och pragmatisk legitimitet, samt centrala teman och nyckelord. Att etablera en levande närvaro på sociala medier som till exempel Twitter, LinkedIn och framför allt Telegram grupper var mycket relevant. I telegram grupper sågs en grupp med många aktiva medlemmar och snabb svarsfrekvens från organisationen som mycket betydelsefullt, samt att ha botar som städar upp irrelevant material utan att deltagarna upplever detta som automatiserat och genuint. Att delta på event och etablera relationer med andra individer inom området och även närliggande områden som till exempel banksektorn var centralt, målet med detta var i många fall att kunna få betydelsefulla individer i sin styrelse av rådgivare vilket ökar legitimiteten. Att kunna ställa organisationens implementering av decentraliserad blockkedjeteknologi i jämförelse med den nuvarande centraliserade lösningen var essentiellt för att locka investerare som var villiga att riskera kapital för en ny modernare lösning.

  • 246946.
    Yusuf, Salim
    et al.
    McMaster Univ, Hamilton Hlth Sci, Populat Hlth Res Inst, Hamilton, ON, Canada.;McMaster Univ, Dept Med, Hamilton, ON, Canada..
    Lonn, Eva
    McMaster Univ, Hamilton Hlth Sci, Populat Hlth Res Inst, Hamilton, ON, Canada.;McMaster Univ, Dept Med, Hamilton, ON, Canada..
    Pais, Prem
    St Johns Res Inst, Bangalore, Karnataka, India..
    Bosch, Jackie
    McMaster Univ, Hamilton Hlth Sci, Populat Hlth Res Inst, Hamilton, ON, Canada.;McMaster Univ, Sch Rehabil Sci, Hamilton, ON, Canada..
    Lopez-Jaramillo, Patricio
    Univ Santander, Fdn Oftalmol Santander, Bucaramanga, Colombia.;Univ Santander, Inst Masira, Sch Med, Bucaramanga, Colombia..
    Zhu, Jun
    Chinese Acad Med Sci, Fu Wai Hosp, Beijing 100730, Peoples R China.;Peking Union Med Coll, Beijing 100021, Peoples R China..
    Xavier, Denis
    St Johns Res Inst, Bangalore, Karnataka, India.;St Johns Med Coll, Bangalore, Karnataka, India..
    Avezum, Alvaro
    Dante Pazzanese Inst Cardiol, Sao Paulo, Brazil..
    Leiter, Lawrence A.
    Univ Toronto, St Michaels Hosp, Li Ka Shing Knowledge Inst, Toronto, ON, Canada.;Univ Toronto, St Michaels Hosp, Keenan Res Ctr Biomed Sci, Toronto, ON, Canada..
    Piegas, Leopoldo S.
    HCor Heart Hosp, Sao Paulo, Brazil..
    Parkhomenko, Alexander
    Inst Cardiol, Kiev, Ukraine..
    Keltai, Matyas
    Semmelweis Univ, Hungarian Inst Cardiol, H-1085 Budapest, Hungary..
    Keltai, Katalin
    Semmelweis Univ, Hungarian Inst Cardiol, H-1085 Budapest, Hungary..
    Sliwa, Karen
    Univ Cape Town, Hatter Inst Cardiovasc Res Africa, Dept Med, Soweto Cardiovasc Res Grp, ZA-7925 Cape Town, South Africa..
    Chazova, Irina
    Inst Clin Cardiol, Russian Cardiol Res Complex, Moscow, Russia..
    Peters, Ron J. G.
    Univ Amsterdam, Acad Med Ctr, Dept Cardiol, Meibergdreef 9, NL-1105 AZ Amsterdam, Netherlands..
    Held, Claes
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Cardiology. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, UCR-Uppsala Clinical Research Center.
    Yusoff, Khalid
    Univ Teknologi Majlis Amansh Rakyat, Selayang, Malaysia.;Univ Coll Sedaya Int Univ, Kuala Lumpur, Malaysia..
    Lewis, Basil S.
    Technion Israel Inst Technol, Ruth & Bruce Rappaport Sch Med, Lady Davis Carmel Med Ctr, Haifa, Israel..
    Jansky, Petr
    Univ Hosp Motol, Prague, Czech Republic..
    Khunti, Kamlesh
    Univ Leicester, Diabet Res Ctr, Leicester, Leics, England..
    Toff, William D.
    Univ Leicester, Dept Cardiovasc Sci, Leicester, Leics, England.;Glenfield Hosp, Natl Inst Hlth Res, Leicester Cardiovasc Biomed Res Unit, Leicester, Leics, England..
    Reid, Christopher M.
    Monash Ctr Cardiovasc Res & Educ Therapeut, Primary Care Diabet & Vasc Med, Melbourne, Vic, Australia.;Curtin Univ, Sch Publ Hlth, Perth, WA 6845, Australia..
    Varigos, John
    Monash Univ, Dept Epidemiol & Prevent Med, Melbourne, Vic 3004, Australia..
    Accini, Jose L.
    Univ Norte, Barranquilla, Colombia..
    McKelvie, Robert
    McMaster Univ, Hamilton Hlth Sci, Populat Hlth Res Inst, Hamilton, ON, Canada.;McMaster Univ, Dept Med, Hamilton, ON, Canada..
    Pogue, Janice
    McMaster Univ, Hamilton Hlth Sci, Populat Hlth Res Inst, Hamilton, ON, Canada.;McMaster Univ, Dept Clin Epidemiol & Biostat, Hamilton, ON, Canada..
    Jung, Hyejung
    McMaster Univ, Hamilton Hlth Sci, Populat Hlth Res Inst, Hamilton, ON, Canada..
    Liu, Lisheng
    Chinese Acad Med Sci, Fu Wai Hosp, Beijing 100730, Peoples R China.;Peking Union Med Coll, Beijing 100021, Peoples R China..
    Diaz, Rafael
    Inst Cardiovasc Rosario, Rosario, Santa Fe, Argentina..
    Dans, Antonio
    Univ Philippines, Coll Med, Manila, Philippines..
    Dagenais, Gilles
    Univ Laval, Inst Univ Cardiol & Pneumol Quebec, Quebec City, PQ, Canada..
    Blood-Pressure and Cholesterol Lowering in Persons without Cardiovascular Disease2016In: New England Journal of Medicine, ISSN 0028-4793, E-ISSN 1533-4406, Vol. 374, no 21, p. 2032-2043Article in journal (Refereed)
    Abstract [en]

    BACKGROUND Elevated blood pressure and elevated low-density lipoprotein (LDL) cholesterol increase the risk of cardiovascular disease. Lowering both should reduce the risk of cardiovascular events substantially.

    METHODS In a trial with 2-by-2 factorial design, we randomly assigned 12,705 participants at intermediate risk who did not have cardiovascular disease to rosuvastatin (10 mg per day) or placebo and to candesartan (16 mg per day) plus hydrochlorothiazide (12.5 mg per day) or placebo. In the analyses reported here, we compared the 3180 participants assigned to combined therapy (with rosuvastatin and the two antihypertensive agents) with the 3168 participants assigned to dual placebo. The first coprimary outcome was the composite of death from cardiovascular causes, nonfatal myocardial infarction, or nonfatal stroke, and the second coprimary outcome additionally included heart failure, cardiac arrest, or revascularization. The median follow-up was 5.6 years.

    RESULTS The decrease in the LDL cholesterol level was 33.7 mg per deciliter (0.87 mmol per liter) greater in the combined-therapy group than in the dual-placebo group, and the decrease in systolic blood pressure was 6.2 mm Hg greater with combined therapy than with dual placebo. The first coprimary outcome occurred in 113 participants (3.6%) in the combined-therapy group and in 157 (5.0%) in the dual-placebo group (hazard ratio, 0.71; 95% confidence interval [CI], 0.56 to 0.90; P=0.005). The second coprimary outcome occurred in 136 participants (4.3%) and 187 participants (5.9%), respectively (hazard ratio, 0.72; 95% CI, 0.57 to 0.89; P=0.003). Muscle weakness and dizziness were more common in the combined-therapy group than in the dual-placebo group, but the overall rate of discontinuation of the trial regimen was similar in the two groups.

    CONCLUSIONS The combination of rosuvastatin (10 mg per day), candesartan (16 mg per day), and hydrochlorothiazide (12.5 mg per day) was associated with a significantly lower rate of cardiovascular events than dual placebo among persons at intermediate risk who did not have cardiovascular disease. (ClinicalTrials.gov number, NCT00468923.)

  • 246947. Yusuf, Salim
    et al.
    Mehta, Shamir R.
    Chrolavicius, Susan
    Afzal, Rizwan
    Pogue, Janice
    Granger, Christopher B.
    Budaj, Andrzej
    Peters, Ron J. G.
    Bassand, Jean-Pierre
    Wallentin, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences.
    Joyner, Campbell
    Fox, Keith A. A.
    Comparison of fondaparinux and enoxaparin in acute coronary syndromes2006In: New England Journal of Medicine, ISSN 0028-4793, E-ISSN 1533-4406, Vol. 354, no 14, p. 1464-1476Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: The combined use of anticoagulants, antiplatelet agents, and invasive coronary procedures reduces ischemic coronary events but also increases bleeding in patients with acute coronary syndromes. We therefore assessed whether fondaparinux would preserve the anti-ischemic benefits of enoxaparin while reducing bleeding. METHODS: We randomly assigned 20,078 patients with acute coronary syndromes to receive either fondaparinux (2.5 mg daily) or enoxaparin (1 mg per kilogram of body weight twice daily) for a mean of six days and evaluated death, myocardial infarction, or refractory ischemia at nine days (the primary outcome); major bleeding; and their combination. Patients were followed for up to six months. RESULTS: The number of patients with primary-outcome events was similar in the two groups (579 with fondaparinux [5.8 percent] vs. 573 with enoxaparin [5.7 percent]; hazard ratio in the fondaparinux group, 1.01; 95 percent confidence interval, 0.90 to 1.13), satisfying the noninferiority criteria. The number of events meeting this combined outcome showed a nonsignificant trend toward a lower value in the fondaparinux group at 30 days (805 vs. 864, P=0.13) and at the end of the study (1222 vs. 1308, P=0.06). The rate of major bleeding at nine days was markedly lower with fondaparinux than with enoxaparin (217 events [2.2 percent] vs. 412 events [4.1 percent]; hazard ratio, 0.52; P<0.001). The composite of the primary outcome and major bleeding at nine days favored fondaparinux (737 events [7.3 percent] vs. 905 events [9.0 percent]; hazard ratio, 0.81; P<0.001). Fondaparinux was associated with a significantly reduced number of deaths at 30 days (295 vs. 352, P=0.02) and at 180 days (574 vs. 638, P=0.05). CONCLUSIONS: Fondaparinux is similar to enoxaparin in reducing the risk of ischemic events at nine days, but it substantially reduces major bleeding and improves long term mortality and morbidity. (ClinicalTrials.gov number, NCT00139815.).

  • 246948. Yusuf, Salim
    et al.
    Mehta, Shamir R.
    Chrolavicius, Susan
    Afzal, Rizwan
    Pogue, Janice
    Granger, Christopher B.
    Budaj, Andrzej
    Peters, Ron J. G.
    Bassand, Jean-Pierre
    Wallentin, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences.
    Joyner, Campbell
    Fox, Keith A. A.
    Effects of fondaparinux on mortality and reinfarction in patients with acute ST-segment elevation myocardial infarction: the OASIS-6 randomized trial2006In: Journal of the American Medical Association (JAMA), ISSN 0098-7484, E-ISSN 1538-3598, Vol. 295, no 13, p. 1519-1930Article in journal (Refereed)
    Abstract [en]

    CONTEXT: Despite many therapeutic advances, mortality in patients with acute ST-segment elevation myocardial infarction (STEMI) remains high. The role of additional antithrombotic agents is unclear, especially among patients not receiving reperfusion therapy. OBJECTIVE: To evaluate the effect of fondaparinux, a factor Xa inhibitor, when initiated early and given for up to 8 days vs usual care (placebo in those in whom unfractionated heparin [UFH] is not indicated [stratum 1] or unfractionated heparin for up to 48 hours followed by placebo for up to 8 days [stratum 2]) in patients with STEMI. DESIGN, SETTING, AND PARTICIPANTS: Randomized double-blind comparison of fondaparinux 2.5 mg once daily or control for up to 8 days in 12,092 patients with STEMI from 447 hospitals in 41 countries (September 2003-January 2006). From day 3 through day 9, all patients received either fondaparinux or placebo according to the original randomized assignment. MAIN OUTCOME MEASURES: Composite of death or reinfarction at 30 days (primary) with secondary assessments at 9 days and at final follow-up (3 or 6 months). RESULTS: Death or reinfarction at 30 days was significantly reduced from 677 (11.2%) of 6056 patients in the control group to 585 (9.7%) of 6036 patients in the fondaparinux group (hazard ratio [HR], 0.86; 95% confidence interval [CI], 0.77-0.96; P = .008); absolute risk reduction, 1.5%; 95% CI, 0.4%-2.6%). These benefits were observed at 9 days (537 [8.9%] placebo vs 444 [7.4%] fondaparinux; HR, 0.83; 95% CI, 0.73-0.94; P = .003, and at study end (857 [14.8%] placebo vs 756 [13.4%] fondaparinux; HR, 0.88; 95% CI, 0.79-0.97; P = .008). Mortality was significantly reduced throughout the study. There was no heterogeneity of the effects of fondaparinux in the 2 strata by planned heparin use. However, there was no benefit in those undergoing primary percutaneous coronary intervention. In other patients in stratum 2, fondaparinux was superior to unfractionated heparin in preventing death or reinfarction at 30 days (HR, 0.82; 95% CI, 0.66-1.02; P = .08) and at study end (HR, 0.77; 95% CI, 0.64-0.93; P = .008). Significant benefits were observed in those receiving thrombolytic therapy (HR, 0.79; P = .003) and those not receiving any reperfusion therapy (HR, 0.80; P = .03). There was a tendency to fewer severe bleeds (79 for placebo vs 61 for fondaparinux; P = .13), with significantly fewer cardiac tamponade (48 vs 28; P = .02) with fondaparinux at 9 days. CONCLUSION: In patients with STEMI, particularly those not undergoing primary percutaneous coronary intervention, fondaparinux significantly reduces mortality and reinfarction without increasing bleeding and strokes. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT00064428.

  • 246949.
    Yusupujiang, Zulipiye
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Languages, Department of Linguistics and Philology.
    Using Unsupervised Morphological Segmentation to Improve Dependency Parsing for Morphologically Rich Languages2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this thesis, we mainly investigate the influence of using unsupervised morphological segmentation as features on the dependency parsing of morphologically rich languages such as Finnish, Estonian, Hungarian, Turkish, Uyghur, and Kazakh. Studying the morphology of these languages is of great importance for the dependency parsing of morphologically rich languages since dependency relations in a sentence of these languages mostly rely on morphemes rather than word order. In order to investigate our research questions, we have conducted a large number of parsing experiments both on MaltParser and UDPipe. We have generated the supervised morphology and the predicted POS tags from UDPipe, and obtained the unsupervised morphological segmentation from Morfessor, and have converted the unsupervised morphological segmentation into features and added them to the UD treebanks of each language. We have also investigated the different ways of converting the unsupervised segmentation into features and studied the result of each method. We have reported the Labeled Attachment Score (LAS) for all of our experimental results.

    The main finding of this study is that dependency parsing of some languages can be improved simply by providing unsupervised morphology during parsing if there is no manually annotated or supervised morphology available for such languages. After adding unsupervised morphological information with predicted POS tags, we get improvement of 4.9%, 6.0%, 8.7%, 3.3%, 3.7%, and 12.0% on the test set of Turkish, Uyghur, Kazakh, Finnish, Estonian, and Hungarian respectively on MaltParser, and the parsing accuracies have been improved by 2.7%, 4.1%, 8.2%, 2.4%, 1.6%, and 2.6% on the test set of Turkish, Uyghur, Kazakh, Finnish, Estonian, and Hungarian respectively on UDPipe when comparing the results from the models which do not use any morphological information during parsing.

  • 246950.
    Yutin, Natalya
    et al.
    NIH, Natl Ctr Biotechnol Informat, Natl Lib Med, Bethesda, MD 20894 USA..
    Bäckstrom, Disa
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular Evolution. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Ettema, Thijs J G
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular Evolution. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Krupovic, Mart
    Inst Pasteur, Dept Microbiol, Unite Biol Mol Gene Chez Extremophiles, Paris, France..
    Koonin, Eugene V.
    NIH, Natl Ctr Biotechnol Informat, Natl Lib Med, Bethesda, MD 20894 USA..
    Vast diversity of prokaryotic virus genomes encoding double jelly-roll major capsid proteins uncovered by genomic and metagenomic sequence analysis2018In: Virology Journal, ISSN 1743-422X, E-ISSN 1743-422X, Vol. 15, article id 67Article in journal (Refereed)
    Abstract [en]

    Background: Analysis of metagenomic sequences has become the principal approach for the study of the diversity of viruses. Many recent, extensive metagenomic studies on several classes of viruses have dramatically expanded the visible part of the virosphere, showing that previously undetected viruses, or those that have been considered rare, actually are important components of the global virome.

    Results: We investigated the provenance of viruses related to tail-less bacteriophages of the family Tectiviridae by searching genomic and metagenomics sequence databases for distant homologs of the tectivirus-like Double JellyRoll major capsid proteins (DJR MCP). These searches resulted in the identification of numerous genomes of viruslike elements that are similar in size to tectiviruses (10-15 kilobases) and have diverse gene compositions. By comparison of the gene repertoires, the DJR MCP-encoding genomes were classified into 6 distinct groups that can be predicted to differ in reproduction strategies and host ranges. Only the DJR MCP gene that is present by design is shared by all these genomes, and most also encode a predicted DNA-packaging ATPase; the rest of the genes are present only in subgroups of this unexpectedly diverse collection of DJR MCP-encoding genomes. Only a minority encode a DNA polymerase which is a hallmark of the family Tectiviridae and the putative family "Autolykiviridae". Notably, one of the identified putative DJR MCP viruses encodes a homolog of Cas1 endonuclease, the integrase involved in CRISPR-Cas adaptation and integration of transposon-like elements called casposons. This is the first detected occurrence of Cas1 in a virus. Many of the identified elements are individual contigs flanked by inverted or direct repeats and appear to represent complete, extrachromosomal viral genomes, whereas others are flanked by bacterial genes and thus can be considered as proviruses. These contigs come from metagenomes of widely different environments, some dominated by archaea and others by bacteria, suggesting that collectively, the DJR MCP-encoding elements have a broad host range among prokaryotes.

    Conclusions: The findings reported here greatly expand the known host range of (putative) viruses of bacteria and archaea that encode a DJR MCP. They also demonstrate the extreme diversity of genome architectures in these viruses that encode no universal proteins other than the capsid protein that was used as the marker for their identification. From a supposedly minor group of bacterial and archaeal viruses, these viruses are emerging as a substantial component of the prokaryotic virome.

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