| 1. |
- Rönnbäck, Annica, et al.
(författare)
-
Gene expression profiling of the rat hippocampus one month after focal cerebral ischemia followed by enriched environment
- 2005
-
Ingår i: Neuroscience Letters. - : Elsevier BV. - 0304-3940 .- 1872-7972. ; 385:2, s. 173-178
-
Tidskriftsartikel (refereegranskat)abstract
- Functional recovery after experimental stroke in rats is enhanced by environmental enrichment by stimulating plastic changes in brain regions outside the lesion, but the molecular mechanisms are not known. We investigated the effect of environmental enrichment after focal cerebral ischemia on cognitive recovery and hippocampal gene expression using microarray analysis. Rats placed in enriched environment (EE) for 1 month after middle cerebral artery occlusion (MCAo) showed significantly improved spatial memory in the Morris water maze compared to rats housed alone after MCAo. Microarray analysis suggested several EE-induced differences in neuronal plasticity-related genes, but these changes could not be confirmed by quantitative real-time PCR. This study highlights some of the potential problems associated with gene expression profiling of brain tissues. Further studies at earlier time points and in additional subregions of the brain are of interest in the search for molecular mechanisms behind EE-induced neuronal plasticity after ischemic stroke.
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
- Dahlqvist, Ralf, et al.
(författare)
-
The concentration and isotopic composition of diffusible Nd in fresh and marine waters
- 2005
-
Ingår i: Earth and Planetary Science Letters. - : Elsevier BV. - 0012-821X .- 1385-013X. ; 233:1-2, s. 9-16
-
Tidskriftsartikel (refereegranskat)abstract
- Variations in the Nd isotopic composition of ocean water through time, recorded in marine deposits, are suggested to document changes in erosional input and ocean circulation. Thus characterization of the dissolved Nd component in seawater is important. But few attempts have been made to directly measure truly dissolved Nd. Here we report Nd data, obtained using the technique of diffusive gradients in thin-films (DGT) designed to measure in situ, diffusible labile trace metals in aqueous solutions. The method samples free ions and possibly very small complexes. The concentration and isotopic composition of Nd in fresh, brackish and seawater have been determined with DGT, analyzed with thermal ionization mass-spectrometry, and compared with filtered and bulk water samples. Concentrations measured in water samples and with DGT show that the relative amount of diffusible Nd increases with salinity, from being about 10% in the fresh water to 42% in seawater. At each sampled site, the isotopic composition of Nd in the water shows a similar isotopic composition, within errors, with Nd sampled using the DGT method. These results indicate that there is a complete exchange between the particulate/colloidal fraction and the truly dissolved phase. Therefore our findings suggest that solute Nd reflects both the isotopic composition of the marine sediments and the bulk water.
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
- Källrot, Niklas, et al.
(författare)
-
Dynamics of Polymer Adsorption from Bulk Solution onto Planar Surfaces
- 2009
-
Ingår i: Macromolecules. - : American Chemical Society (ACS). - 0024-9297 .- 1520-5835. ; 42:10, s. 3641-3649
-
Tidskriftsartikel (refereegranskat)abstract
- Polymer adsorption of uncharged homopolymers onto planar surfaces has been investigated by employing a coarse-grained bcad-spring polymer model using simulation techniques. Polymer solutions of two different densities and polymers of two different Contour lengths have been examined. The dynamics of the adsorption process appearing in systems composed of a polymer Solution placed near attractive. but initially polymer-free, surfaces were determined by Brownian dynamics simulations and equilibrium properties of corresponding systems by Monte Carlo simulations. The properties of the systems have been analyzed by monitoring the number of adsorbed polymers, bead density profiles, time and frequency of polymer attachments, spatial extension of polymers perpendicular and parallel to the surface, and configurational characteristics. Initially, the polymers diffuse toward the Surfaces, and at shorter distances the attractive Surface potential starts to pull the polymers toward the surface, making them slightly stretched perpendicular to the Surface. Thereafter, the polymers collapse onto the surface with multiple anchoring, and a slower relaxation increasing the extension of the polymers parallel to the Surfaces appears. Finally, at even longer times, and connected to the slow relaxation of the number of adsorbed polymers, the extension of the polymer coils parallel to the Surface is reduced. and the perpendicular extension is increased, with associated changes of the number of beads residing in tails, loop, and trains. The adsorption process becomes faster at decreasing polymer length and at increasing polymer density.
|
|
| 9. |
- Rönnbäck, Annica, et al.
(författare)
-
Diurnal effects of enriched environment in immediate early gene expression in the rat brain
- 2005
-
Ingår i: Brain research. - : Elsevier BV. - 0006-8993. ; 1046:1-2, s. 137-144
-
Tidskriftsartikel (refereegranskat)abstract
- Rodents housed in an enriched environment (EE) show increased neuronal plasticity with enhanced long-term potentiation and memory performance. We report an EE-induced increase in NGFI-A and Krox-20 mRNA expression exclusively during the dark period of the day. In addition, EE-housed rats showed considerable diurnal variation in NGFI-A, Krox-20, and NGFI-B mRNA expression which was absent in single-housed rats. Thus, EE-induced molecular changes are more evident during the dark phase when the rats have higher motor and exploratory activity. This is important to take into account in future studies of molecular mediators of experience-dependent neuronal plasticity.
|
|
| 10. |
|
|
