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| 2. |
- Arnborg, Stefan, et al.
(författare)
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Data Mining in Schizophrenia Research - preliminary analysis
- 2002
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Konferensbidrag (refereegranskat)abstract
- We describe methods used and some results in a study of schizophrenia in a population of affected and unaffected participants, called patients and controls. The subjects are characterized by diagnosis, genotype, brain anatomy (MRI), laboratory tests on blood samples, and basic demographic data. The long term goal is to identify the causal chains of processes leading to disease. We describe a number of preliminary findings, which confirm earlier results on deviations of brain tissue volumes in schizophrenia patients, and also indicate new effects that are presently under further investigation. More importantly, we discuss a number of issues in selection of methods from the very large set of tools in data mining and statistics.
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| 4. |
- Evilevitch, Alex, et al.
(författare)
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Kinetics of oil solubilization in microemulsion droplets. Mechanism of oil transport.
- 2001
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Ingår i: Electroanalysis. - : American Chemical Society (ACS). - 1040-0397. ; 16:23, s. 8755-8762
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Tidskriftsartikel (refereegranskat)abstract
- We have studied the kinetics of the solubilization of oil through a temperature jump into a droplet microemulsion phase in the system water-pentaethylene oxide dodecyl ether-decane at 25 C. The initial state is formed by subjecting the equilibrium system at 25 C to a temperature quench to 22, 20, and 14 C, respectively. At this lower temperature, which at equilibrium corresponds to a two-phase system, oil droplets form and grow in size with increasing time. By varying the time between the quench and the T-jump, the size of the initial oil drops is varied in a systematic and known way in the relaxation study. The relaxation process is monitored by following the turbidity of the system. We find that for all the systems the relaxation back to equlibrium is much faster than the drop growth process observed after the temperature quench. This general observation is explained by realizing that the redissolution of the oil drops is analogous to the oil transfer phase, which in the quench experiment occurs prior to the Ostwald ripening phase. More significant is that we observed a qualitative transition in the relaxation behavior when the initial aggregate distribution is varied. In all cases we have the same initial temperature and overall composition and one population of many small droplets and fewer larger drops. The size of the larger drops only affects the relaxation in a quantitative way. If the small droplets are only slightly smaller than the equilibrium size, equilibration occurs through the diffusion of oil molecules in the bulk phase. When the initial droplets are sufficiently small, a new kinetic route is available where there is an efficient direct oil transfer between the small droplets and large drops. This allows for a fast relaxation of the oil distribution between the two populations of drops.
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| 5. |
- Evilevitch, Alex, et al.
(författare)
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Molecular transport in a nonequilibrium droplet microemulsion system.
- 2001
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 17:22, s. 6893-6904
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we consider the problem of oil molecular transport between nonequilibrium microemulsion oil droplets in water. In particular, we have investigated the kinetics of solubilization of big oil drops by smaller microemulsion droplets transforming a bimodal size distribution into an equilibrium microemulsion with a unimodal size distribution. The process involves the diffusion of oil monomers across the aqueous solvent. Solubilization experiments are presented on a well-characterized nonionic microemulsion system, where interfacial area and dispersed volume are conserved and where the excess oil chemical potential is dominated by interfacial curvature energy. An analysis of the experiments shows that the solubilization kinetics depend significantly on the concentrations and sizes of big and small droplets. We formulate a quantitative model for the solubilization kinetics where the effects of size and concentrations are treated within the framework of a cell model. A quantitative agreement between model and experiment is obtained, and the analysis also shows that the majority of oil monomers are captured by small droplets already in the vicinity of the big drop surface when the concentration of small droplets is high.
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| 6. |
- Flycht-Eriksson (Silvervarg), Annika, et al.
(författare)
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Ontology-driven Information-providing Dialogue Systems
- 2003
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Ingår i: Proceedings of the Americas Conference on Information Systems<em></em>. - : Association for Information Systems.
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Konferensbidrag (refereegranskat)
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| 7. |
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| 8. |
- Jönsson, Bo, et al.
(författare)
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Ion-ion correlations in liquid dispersions
- 2004
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Ingår i: Journal of Adhesion. - : Informa UK Limited. - 0021-8464. ; 80:5, s. 339-364
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Tidskriftsartikel (refereegranskat)abstract
- Ion-ion correlations play an important role in liquid dispersion with, strong eleetrostatic inlet-actions. Examples can be found in very diverse areas with the setting of cement paste as one extreme and the compactation, of DNA as another. One particularly spectacular effect of ion-ion correlations is that the traditional double layer repulsion sometimes can be converted into a net attraction. This typically takes place in the presence of multivalent counterions and/or in solutions with low dielectric permittivity. The attractive forces are driven by the energy while the repulsive are mainly of entropic origin, and the final outcome is a delicate balance of these contributions. Here we present two simple models, which give a conceptually simple description of this balance.
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| 9. |
- Jönsson, Bo, et al.
(författare)
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Onset of cohesion in cement paste
- 2004
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 20:16, s. 6702-6709
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Tidskriftsartikel (refereegranskat)abstract
- It is generally agreed that the cohesion of cement paste occurs through the formation of a network of nanoparticles of a calcium-silicate-hydrate ("C-S-H"). However, the mechanism by which these particles develop this cohesion has not been established. Here we propose a dielectric continuum model which includes all ionic interactions within a dispersion of C-S-H particles. It takes into account all co-ions and counterions explicitly (with pure Coulomb interactions between ions and between ions and the surfaces) and makes no further assumptions concerning their hydration or their interactions with the surface sites. At high surface charge densities, the model shows that the surface charge of C-S-H particles is overcompensated by Ca2+ ions, giving a reversal of the apparent particle charge. Also, at high surface charge densities, the model predicts that the correlations of ions located around neighboring particles causes an attraction between the particle surfaces. This attraction has a range of approximately 3 nm and a magnitude of 1 nN, values that are in good agreement with recent AFM experiments. These predictions are stable with respect to small changes in surface-surface separation, hydrated ion radius, and dielectric constant of the solution. The model also describes the effect of changes in cement composition through the introduction of other ions, either monovalent (Na) or multivalent (aluminum or iron hydroxide).
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| 10. |
- Jönsson, Bodil, et al.
(författare)
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Situated research and design for everyday life
- 2004
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This paper elaborates theoretical and methodological aspects of design processes in a disability context and aims to relate them to other sciences. It particularly emphasizes situated aspects of research: the need for being there, with the users in their
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