| 1. |
- Andresen Bergström, Moa, 1978, et al.
(författare)
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A skin-like cytochrome P450 cocktail activates prohaptens to contact allergenic metabolites.
- 2007
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Ingår i: The Journal of investigative dermatology. - : Elsevier BV. - 1523-1747 .- 0022-202X. ; 127:5, s. 1145-53
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Tidskriftsartikel (refereegranskat)abstract
- Allergic contact dermatitis is a complex syndrome representing immunological responses to cutaneous exposure to protein-reactive chemicals. Although many contact sensitizers directly can elicit this disorder, others (prohaptens) require activation. Knowledge regarding the activating mechanisms remains limited, but one possibility is metabolic activation by cytochrome P450 (CYP) enzymes in the skin. We have, after quantitative reverse transcriptase-PCR studies of the CYP content in 18 human skin samples, developed an enriched skin-like recombinant human (rh) CYP cocktail using CYP1A1, 1B1, 2B6, 2E1, and 3A5. To validate the rhCYP cocktail, a prohaptenic conjugated diene ((5R)-5-isopropenyl-2-methyl-1-methylene-2-cyclohexene) was investigated using: the skin-like rhCYP cocktail, a liver-like rhCYP cocktail, single rhCYP enzymes, liver microsomes, keratinocytes, and a dendritic cell (DC) assay. The diene was activated to sensitizing epoxides in all non-cell-based incubations including the skin-like rhCYP cocktail. An exocyclic epoxide metabolite ((7R)-7-isopropenyl-4-methyl-1-oxaspiro[2.5]oct-4-ene) was found to be mainly responsible for the allergenic activity of the diene. This epoxide also induced pronounced DC activation indicated by upregulation of IL-8. The skin-like rhCYP cocktail provides a simplified alternative to using skin tissue preparations in mechanistic studies of CYP-mediated skin metabolism of prohaptens and offers the future possibility of designing in vitro predictive assays for assessment of allergenic activity of prohaptens.
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| 2. |
- Bråtå, Hans Olav, et al.
(författare)
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Users’ role in innovation processes in the sports equipment industry : experiences and lessons
- 2009
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The main objective of this project is to contribute to our knowledge about user-driven innovation and to suggest how knowledge on user-driven innovation may be included in innovation efforts and systems both for the sports equipment industry and for other industries. The study is primarily based on case studies of how firms within the Nordic sports equipment and outdoor industry involve users in their innovation efforts. Our studies concentrate on firms producing equipment for winter sport and outdoor recreation. The study builds upon a large number of interviews with firms and key persons as well as extensive analysis of available written material and research literature. The results focus on the identification of certain key user groups in the sports equipment innovation cycle: user innovators, professional and sponsored users, enthusiastic amateurs, passionate insiders and chains and retailers. We consider the extent to which these users influence or take part in innovation processes within technical design, visual design, branding and the development of product systems. The report concludes with policy recommendations for how firms may take advantage of each user group. In this respect we present some key points and examples on firms’ interaction with users in innovation processes. Other recommendations consider public policy and suggest that public policy ought to encourage firms to take advantage of knowledge held by those groups. In society a large number of user groups exist and public policy ought to stimulate use of their knowledge for a broader purpose, including societal development. Merging user groups in order to stimulate cross sector development, in addition to organising meeting places may be a theme for public policy at the regional level.
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| 3. |
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| 4. |
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| 5. |
- Hotz, Ingrid, et al.
(författare)
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Tensor Field Visualization Using a Metric Interpretation
- 2006
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Ingår i: Visualization and Image Processing of Tensor Fields. - Berlin, Heidelberg : Springer. - 9783540250326 - 9783540312727 ; , s. 269-281
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Bokkapitel (refereegranskat)abstract
- This chapter introduces a visualization method specifically tailored to the class of tensor fields with properties similar to stress and strain tensors. Such tensor fields play an important role in many application areas such as structure mechanics or solid state physics. The presented technique is a global method that represents the physical meaning of these tensor fields with their central features: regions of compression or expansion. The method consists of two steps: first, the tensor field is interpreted as a distortion of a flat metric with the same topological structure; second, the resulting metric is visualized using a texture-based approach. The method supports an intuitive distinction between positive and negative eigenvalues.
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| 6. |
- Meier, Holger A., et al.
(författare)
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Visualization of Particle Interactions in Granular Media
- 2008
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Ingår i: IEEE Transactions on Visualization & Computer Graphics. - : IEEE Computer Society. - 1077-2626. ; 14:5, s. 1110-1125
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Tidskriftsartikel (refereegranskat)abstract
- Interaction between particles in so-called granular media, such as soil and sand, plays an important role in the context of geomechanical phenomena and numerous industrial applications. A two scale homogenization approach based on a micro and a macro scale level is briefly introduced in this paper. Computation of granular material in such a way gives a deeper insight into the context of discontinuous materials and at the same time reduces the computational costs. However, the description and the understanding of the phenomena in granular materials are not yet satisfactory. A sophisticated problem-specific visualization technique would significantly help to illustrate failure phenomena on the microscopic level. As main contribution, we present a novel 2D approach for the visualization of simulation data, based on the above outlined homogenization technique. Our visualization tool supports visualization on micro scale level as well as on macro scale level. The tool shows both aspects closely arranged in form of multiple coordinated views to give users the possibility to analyze the particle behavior effectively. A novel type of interactive rose diagrams was developed to represent the dynamic contact networks on the micro scale level in a condensed and efficient way.
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| 7. |
- Ott, Hagen, et al.
(författare)
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Cutaneous metabolic activation of carvoxime, a self-activating, skin-sensitizing prohapten.
- 2009
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Ingår i: Chemical Research in Toxicology. - : American Chemical Society (ACS). - 0893-228X .- 1520-5010. ; 22:2, s. 399-405
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Tidskriftsartikel (refereegranskat)abstract
- Bioactivation of low molecular weight compounds in the skin can cause contact sensitization. We have previously shown that the alpha, beta-R-unsaturated oxime R-carvoxime [1, (R)-2-methyl-5-isopropenylcyclohex-2-enone oxime] is bioactivated to two diastereomeric highly reactive and strongly sensitizing alpha, beta-epoxy oxime metabolites. To investigate if this metabolic activation is catalyzed by the major cytochrome P450 (P450) enzymes found in human skin, incubations of 1 with a skinlike P450 cocktail in the presence of glutathione were carried out. We identified three glutathione conjugates in the incubation mixture arising from two diasteomeric alpha, beta-epoxy oxime metabolites of 1, thus showing that the metabolic activation of 1 is P450-mediated. A P450 identification study using the individual P450 enzymes present in the skinlike P450 cocktail showed the involvement of P450 1A1 and 1B1 and also to some extent 2B6. P450 1B1 metabolism of 1 was found to be stereoselective as glutathione conjugates from only one of the alpha, beta-epoxyoxime metabolites were identified (metabolite 2). Additionally, 1 was found to be an inducer of P450 1B1 (but not 1A1) in human monocyte-derived dendritic cells (moDCs) and to some extent in normal human epidermal keratinocytes. A further transcriptional gene expression change observed in moDCs was a 44-fold upregulation of IL-8, a marker often used for assessment of sensitizing potential of contact allergens. The autoinduction of P450 1B1 by 1 may be a key event in the development of contact allergy to 1 and may also explain why only metabolite 2, and not 3, was found to elicit an allergic response in mice sensitized to 1. Our data show that the alpha, beta-unsaturated oxime 1 is bioactivated by human cutaneous P450, thus forming highly allergenic metabolites, and has the potential to induce its own bioactivation pathway, particularly in antigen-presenting cells.
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| 8. |
- Schlemmer, Michael, et al.
(författare)
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Clifford Pattern Matching for Color Image Edge Detection
- 2006
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Ingår i: Visualization of Large and Unstructured Data Sets. - : GI-Edition. - 9783885794387 ; , s. 47-58
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Bokkapitel (refereegranskat)abstract
- Feature detection and pattern matching play an important role in visualization.Originally developed for images and scalar fields, pattern matching methods become increasingly interesting for other applications, e.g., vector fields. To apply pattern matching to vector fields the basic concepts of convolution and fast Fourier transform (FFT) have to be generalized to vector fields. A formalism supporting an elegant generalization of these concepts is provided by the Clifford Algebra, originally developed for describing geometry and geometric operations. We discuss an application of the Clifford Pattern Matching (CPM). We apply CPM to images for ”Clifford Color Edge Detection” (C2ED), an approach for detecting edges and other features in color images. The basic idea is to treat color value tripels as vectors and apply the pattern matching algorithm to the resulting vector field. We introduce vector-valued filters for edge detection and present results.
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| 9. |
- Schlemmer, Michael, et al.
(författare)
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Comparative Visualization of Two-Dimensional Flow Data Using Moment Invariants
- 2009
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Konferensbidrag (refereegranskat)abstract
- The analysis of time-dependent data is often guided by the question of how dominant structures develop over time. It is important to understand how patterns or structures identified for one time step evolve over time, by changing or moving in the domain. To gain insight into such evolving structural change it is crucial to effectively compare different time steps. This paper proposes a comparison method for twodimensional flow fields. The method is based on a feature description using invariant moments. The specific strength of these moments is their invariance under scaling and rotation, thus facilitating an identification of features even if they occur at other positions, with changed orientation, and variation in size. In addition the moments themselves can beused to define a similarity measure. To evaluate the significance of this concept it has been applied to wind speed data from meteorological simulations.
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| 10. |
- Schlemmer, Michael, et al.
(författare)
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Fast Clifford Fourier transfor- mation for unstructured vector field data.
- 2005
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Konferensbidrag (refereegranskat)abstract
- Vector fields play an important role in many areas of computational physics and engineering. For effective visualization of vector fields it is necessary to identify and extract important features inherent in the data, defined by filters that characterize certain “patterns”. Our prior approach for vector field analysis used the Clifford Fourier transform for efficient pattern recognition for vector field data defined on regular grids [1,2]. Using the frequency domain, correlation and convolution of vectors can be computed as a Clifford multiplication, enabling us to determine similarity between a vector field and a pre-defined pattern mask (e.g., for critical points). Moreover, compression and spectral analysis of vector fields is possible using this method. Our current approach only applies to rectilinear grids. We combine this approach with a fast Fourier transform to handle unstructured scalar data [6]. Our extension enables us to provide a feature-based visualization of vector field data defined on unstructured grids, or completely scattered data. Besides providing the theory of Clifford Fourier transform for unstructured vector data, we explain how efficient pattern matching and visualization of various selectable features can be performed efficiently. We have tested our method for various vector data sets.
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