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Träfflista för sökning "WFRF:(Åstrand Olof) "

Search: WFRF:(Åstrand Olof)

  • Result 1-10 of 29
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1.
  • Engström, Lars-Magnus, 1938-, et al. (author)
  • Olle Halldén : Nekrolog
  • 2005
  • Other publication (pop. science, debate, etc.)abstract
    • Olle Halldén var en svensk pionjär och centralgestalt inom pedagogik och humaniora inom kroppsövningsområdet i Sverige. Han var utbildad till gymnastikdirektör och under många år lärare vid Kungl. Gymnastiska Centralinsitutet/Gymnastik- och idrottshögskolan i Stockholm. 
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2.
  • Franck, Niclas, et al. (author)
  • Cardiovascular risk factors related to the PPARγ Pro12Ala polymorphism in patients with type 2 diabetes are gender dependent
  • 2012
  • In: Blood Pressure. - : Informa Healthcare. - 0803-7051 .- 1651-1999. ; 21:2, s. 122-127
  • Journal article (peer-reviewed)abstract
    • The interaction of the PPARγ Pro12Ala polymorphism with diabetes and cardiovascular risk is controversial. We studied 173 women and 309 men in the observational CARDIPP trial in which determination of left ventricular mass, carotid intima-media thickness (IMT) and pulse wave velocity (PWV) were performed. Blood pressures were measured with 24-h ambulatory technique (ABP). Heterozygotes and homozygotes of Ala were defined as Ala in the analyses. Men with Ala-isoform displayed higher waist circumference (Ala: 107 ± 14 cm, Pro: 104 ± 11 cm, p = 0.045) and body weight (Ala: 95.7 ± 18 kg, Pro: 91.6 ± 14 kg, p = 0.042) than Pro-homozygotes. Men with ALA-isoform also showed higher systolic ABP levels (Ala: 134 ± 15 mmHg, Pro: 130 ± 14 mmHg, p = 0.004), whereas left ventricular mass index, IMT and PWV were unrelated to isoforms. In contrast, carotid–radial PWV was lower in women with the Ala-isoform (Ala: 7.9 ± 1.0 m/s, Pro: 8.5 ± 1.3 m/s, p = 0.01) and levels of apolipoprotein A1 were higher (Ala: 1.43 ± 0.27 g/l, Pro: 1.35 ± 0.17 g/l, p = 0.03). In conclusion, we found that men with type 2 diabetes having the Ala-isoform of PPARγ Pro12Ala had an unfavorable cardiovascular risk profile, whereas women with this isoform had lower carotid–radial PWV and higher apolipoprotein A1 levels suggesting a beneficial prognosis. These differences according to gender of the ALA isoform in type 2 diabetes deserve further attention.
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3.
  • Harczuk, Ignat, 1987- (author)
  • Atomic decomposition of molecular properties
  • 2016
  • Doctoral thesis (other academic/artistic)abstract
    • In this thesis, new methodology of computing properties aimed for multipleapplications is developed. We use quantum mechanics to compute propertiesof molecules, and having these properties as a basis, we set up equations basedon a classical reasoning. These approximations are shown to be quite good inmany cases, and makes it possible to calculate linear and non-linear propertiesof large systems.The calculated molecular properties are decomposed into atomic propertiesusing the LoProp algorithm, which is a method only dependent on the overlapmatrix. This enables the expression of the molecular properties in the two-site atomic basis, giving atomic, and bond-centric force-fields in terms of themolecular multi-pole moments and polarizabilities. Since the original LoProptransformation was formulated for static fields, theory is developed which makesit possible to extract the frequency-dependent atomic properties as well. Fromthe second-order perturbation of the electron density with respect to an externalfield, LoProp is formulated to encompass the first order hyperpolarizability.The original Applequist formulation is extended into a quadratic formula-tion, which produces the second-order shift in the induced dipole moments of thepoint-dipoles from the hyperpolarizability. This enables the calculation of a to-tal hyperpolarizability in systems consisting of interacting atoms and molecules.The first polarizability α and the first hyperpolarizability β obtained via theLoProp transformation are used to calculate this response with respect to anexternal field using the quadratic Applequist equations.In the last part, the implemented analytical response LoProp procedureand the quadratic Applequist formalism is applied to various model systems.The polarizable force-field that is obtained from the decomposition of the staticmolecular polarizability α is tested by studying the one-photon absorption spec-trum of the green fluorescent protein. From the frequency dispersion of thepolarizability α(ω), the effect of field perturbations is evaluated in classicaland QM/MM applications. Using the dynamical polarizabilities, the Rayleigh-scattering of aerosol clusters consisting of water and cis–pinonic acid moleculesis studied. The LoProp hyperpolarizability in combination with the quadraticApplequist equations is used to test the validity of the model on sample wa-ter clusters of varying sizes. Using the modified point-dipole model developedby Thole, the hyper-Rayleigh scattering intensity of a model collagen triple-helix is calculated. The atomic dispersion coefficients are calculated from thedecomposition of the real molecular polarizability at imaginary frequencies. Fi-nally, using LoProp and a capping procedure we demonstrate how the QM/MMmethodology can be used to compute x-ray photoelectron spectra of a polymer.
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4.
  • Johansson, Ulrika, 1974-, et al. (author)
  • Assembly of functionalized silk together with cells to obtain proliferative 3D cultures integrated in a network of ECM-like microfibers
  • 2019
  • In: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 9, s. 1-13
  • Journal article (peer-reviewed)abstract
    • Tissues are built of cells integrated in an extracellular matrix (ECM) which provides a three-dimensional (3D) microfiber network with specific sites for cell anchorage. By genetic engineering, motifs from the ECM can be functionally fused to recombinant silk proteins. Such a silk protein, FN-silk, which harbours a motif from fibronectin, has the ability to self-assemble into networks of microfibers under physiological-like conditions. Herein we describe a method by which mammalian cells are added to the silk solution before assembly, and thereby get uniformly integrated between the formed microfibers. In the resulting 3D scaffold, the cells are highly proliferative and spread out more efficiently than when encapsulated in a hydrogel. Elongated cells containing filamentous actin and defined focal adhesion points confirm proper cell attachment to the FN-silk. The cells remain viable in culture for at least 90 days. The method is also scalable to macro-sized 3D cultures. Silk microfibers formed in a bundle with integrated cells are both strong and extendable, with mechanical properties similar to that of artery walls. The described method enables differentiation of stem cells in 3D as well as facile co-culture of several different cell types. We show that inclusion of endothelial cells leads to the formation of vessel-like structures throughout the tissue constructs. Hence, silk-assembly in presence of cells constitutes a viable option for 3D culture of cells integrated in a ECM-like network, with potential as base for engineering of functional tissue.
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5.
  • Kubyshkina, Elena, 1990- (author)
  • Ab initio modelling of interfaces in nanocomposites for high voltage insulation
  • 2018
  • Doctoral thesis (other academic/artistic)abstract
    • Dielectric nanocomposite materials have been experimentally proven to have properties that are beneficial in applications for efficient energy transport. However, today there are still no empirical models or rules that can predict the performance of a certain combination of materials in the nanocomposite, and there are also no definitive explanations of their dielectric behavior. A deeper understanding of the phenomena behind these materials' response to an applied electric field can open new possibilities for improvement of the insulating properties of nanocomposites.The goal of this work is to locate the key processes that are responsible for dielectric performance. The methodology of the study is based on ab initio technology, that relies solely on the knowledge of chemical and structural composition of the material. In this work, the charge-related properties of nanocomposite interfaces are studied. The primary material of the study is chosen to be polyethylene-based composite with magnesium oxide nanoparticles.The impact of the nanoparticle crystal surface termination and its silane treatment on the electronic structure of the interface between MgO and polyethylene are investigated here. Moreover, the effects of presence of carboxyl defect and water molecule near the interface are considered in this work as well.Based on the calculated electronic structure data, a model for charge dynamics is proposed. The model explains mechanisms for conductivity and space charge reduction in nanocomposites, but also predicts an increase in thermal stress and susceptibility for chemical defects. It is suggested here that the suppression mechanisms for space charge and conductivity in nanocomposites are inherently unstable and can also accelerate material aging.
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6.
  • Romu, Thobias, et al. (author)
  • The effect of flip-angle on body composition using calibrated water-fat MRI.
  • 2016
  • Conference paper (other academic/artistic)abstract
    • This study tested how the flip angle affects body composition analysis by MRI, if adipose tissue is used as an internal intensity reference. Whole-body water-fat images with flip angle 5° and 10° were collected from 29 women in an ongoing study. The images were calibrated based on the adipose tissue signal and whole-body total adipose, lean and soft tissue volumes were measured. A mean difference of 0.29 L, or 0.90 % of the average volume, and a coefficient of variation of 0.40 % was observed for adipose tissue.
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10.
  • Sjöqvist, Jonas, 1985- (author)
  • Light interactions in flexible conjugated dyes
  • 2014
  • Doctoral thesis (other academic/artistic)abstract
    • In this thesis methodological developments have been made for the description of flexible conjugated dyes in room temperature spectrum calculations.The methods in question target increased accuracy and efficiency by combining classical molecular dynamics (MD) simulations with time-dependent response theory spectrum calculations. For absorption and fluorescence spectroscopies a form of conformational averaging is used, where the final spectrum is obtained as an average of spectra calculated for geometries extracted from ground and excited state MD simulations. For infrared and Raman spectroscopies averaged spectra are calculated based on individual spectra, obtained for zero-temperature optimized molecular structures, weighted by conformational statistics from MD trajectories. Statistics for structural properties are also used in both cases to gain additional information about the systems, allowing more efficient utilization of computational resources. As it is essential that the molecular mechanics description of the system is highly accurate for methods of this nature to be effective, high quality force field parameters have been derived, describing the molecules of interest in either the MM3 or CHARMM force fields.These methods have been employed in the study of three systems. The first is a platinum(II) actylide chromophore used in optical power limiting materials, for which a ultraviolet/visible absorption spectrum has been calculated. The second is a family of molecular probes called luminescent conjugated oligothiophenes, used to detect and characterize amyloid proteins, for which both absorption and fluorescence spectra have been calculated. Finally, infrared and Raman spectra have been calculated for a group of branched oligothiophenes used in organic solar cells.In addition, solvation effects have been studied for conjugated poly\-eletrolytes in water, resulting in the development of two solvation models suitable for this class of molecules. The first uses a quantum meachanics/molecular mechanics (QM/MM) description, in which the solute mole\-cule is described using accurate quantum mechanical methods while the surrounding water molecules are described using point charges and polarizable point dipoles. The second discards the water entirely and removes the ionic groups of the solute. The QM/MM model provides highly accurate results while the cut-down model gives results of slightly lower quality but at a much reduced computational cost.Finally, a study of protein-dye interactions has been performed, with the goal of explaining changes in the luminescence properties of the LCO chromophores when in the presence of amyloid proteins. Results were less than conclusive.
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  • Result 1-10 of 29
Type of publication
conference paper (9)
journal article (9)
doctoral thesis (5)
other publication (3)
book (1)
book chapter (1)
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licentiate thesis (1)
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Type of content
peer-reviewed (14)
other academic/artistic (11)
pop. science, debate, etc. (4)
Author/Editor
Lindahl, Olof A. (6)
Andersson, Britt M. (6)
Jalkanen, Ville (6)
Åstrand, Anders (5)
Romu, Thobias (4)
Borga, Magnus (4)
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Hammar, Mats (4)
Lindh-Åstrand, Lotta (4)
Lindahl, Olof (4)
Lindblom, Hanna (4)
Jalkanen, Ville, 197 ... (4)
West, Janne (3)
Åstrand, Per-Olof, 1 ... (3)
Dahlqvist Leinhard, ... (2)
Dahlqvist Leinhard, ... (2)
Schantz, Peter, 1954 ... (2)
Andersson, Britt, 19 ... (2)
Schantz, Peter (2)
Berin, Emilia (2)
Spetz Holm, Anna-Cla ... (2)
Spetz, Anna-Clara (2)
West, Janne, 1982- (1)
Karlsson, Anette (1)
Wahlund, Lars-Olof (1)
Berggren, Per-Olof (1)
Nilsson, Christer (1)
Engvall, Jan (1)
Länne, Toste (1)
Norman, Patrick, Pro ... (1)
Åstrand, Carolina (1)
Ekblom, Örjan, 1971- (1)
Eriksson, Sture (1)
Ågren, Hans, Profess ... (1)
Östgren, Carl Johan (1)
Wallin, Anders (1)
Kilander, Lena (1)
Gasser, Christian (1)
Nyström, Fredrik (1)
Hedhammar, My (1)
Vahtras, Olav, Profe ... (1)
Widhe, Mona (1)
Franck, Niclas (1)
Johansson, Ulrika, 1 ... (1)
Åstrand, Ragnar (1)
Engström, Lars-Magnu ... (1)
Jonsson, B. Lars G., ... (1)
Almgren, Ulf (1)
Dunberger, Bertil (1)
Åstrand, Olof (1)
Lindström, Torbjön (1)
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University
Umeå University (11)
The Swedish School of Sport and Health Sciences (7)
Linköping University (6)
Royal Institute of Technology (3)
Luleå University of Technology (2)
Uppsala University (1)
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Linnaeus University (1)
Karolinska Institutet (1)
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Language
English (22)
Swedish (7)
Research subject (UKÄ/SCB)
Engineering and Technology (16)
Medical and Health Sciences (8)
Natural sciences (3)
Humanities (1)

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