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| 3. |
- Malm, T M, et al.
(författare)
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Bone-marrow-derived cells contribute to the recruitment of microglial cells in response to beta-amyloid deposition in APP/PS1 double transgenic Alzheimer mice
- 2005
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Ingår i: Neurobiology of Disease. - : Elsevier BV. - 0969-9961. ; 18:1, s. 134-142
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Tidskriftsartikel (refereegranskat)abstract
- The role of microglia recruited from bone marrow (BM) into the CNS during the progression of Alzheimer's disease (AD) is poorly understood. To investigate whether beta-amyloid (Abeta) associated microglia are derived from blood monocytes, we transplanted BM cells from enhanced green fluorescent protein expressing mice into young or old transgenic AD mice and determined the engraftment of BM-derived cells into the brain and their relative distribution near Abeta deposits. When young transgenic mice were transplanted before the onset of AD-like pathology and the brains analyzed 6.5 months later, the number of engrafted cells was significantly higher than in age-matched wild type mice. Moreover, the number of BM-derived cells associated with Abeta was significantly higher than in old transgenic mice transplanted after the establishment of AD-like pathology. Local inflammation caused by intrahippocampal lipopolysaccharide injection significantly increased the engraftment of BM-derived cells in old AD mice and decreased the hippocampal Abeta burden. These results suggest that infiltration of BM-derived monocytic cells into the brain contributes to the development of microglial reaction in AD.
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| 4. |
- von Haartman, M., et al.
(författare)
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Impact of strain and channel orientation on the low-frequency noise performance of Si n- and pMOSFETs
- 2007
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Ingår i: Solid-State Electronics. - : Elsevier BV. - 0038-1101 .- 1879-2405. ; 51:5, s. 771-777
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Tidskriftsartikel (refereegranskat)abstract
- Mobility and low-frequency (LF) noise were studied in tensile strained Si n- and pMOSFETs fabricated on relaxed SiGe virtual substrates. Both the impact of the channel orientation ((110) or (100) on (100) Si) and the tensile strain were carefully investigated. Two types of virtual substrates were used; a thin relaxed SiGe layer (20% Ge) and a thick one (27% Ge). The strained Si nMOSFETs fabricated on the thin substrate showed similar LF noise level as in the reference devices, whereas the thick substrate caused severely increased LF noise in the nMOSFETs. The latter was linked to the higher Ge concentration and explained by possible misfit dislocations and increased defect densities, likely resulting from strain relaxation caused by ion implantation damage. On the other hand, considerably lower LF noise was achieved in the pMOSFETs on the thick SiGe. The channel orientation was not found to have a significant influence on the LF noise performance in any of the studied devices.
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| 7. |
- Driussi, F., et al.
(författare)
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On the electron mobility enhancement in biaxially strained Si MOSFETs
- 2008
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Ingår i: Solid-State Electronics. - : Elsevier BV. - 0038-1101 .- 1879-2405. ; 52:4, s. 498-505
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Tidskriftsartikel (refereegranskat)abstract
- This paper reports a detailed experimental and simulation study of the electron mobility enhancement induced by the biaxial strain in (001) silicon MOSFETs. To this purpose, ad hoc test structures have been fabricated on strained Si films grown on different SiGe virtual substrates and the effective mobility of the electrons has been extracted. To interpret the experimental results, we performed simulations using numerical solutions of Schroedinger-Poisson equations to calculate the charge and the momentum relaxation time approximation to calculate the mobility. The mobility enhancement with respect to the unstrained Si device has been analyzed as a function of the Ge content of SiGe substrates and of the operation temperature.
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| 8. |
- Eklund, B., et al.
(författare)
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Toxic effects of decomposing red algae on littoral organisms
- 2005
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Ingår i: Estuarine, Coastal and Shelf Science. - 0272-7714 .- 1096-0015. ; 62:4, s. 621-626
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Tidskriftsartikel (refereegranskat)abstract
- Large masses of filamentous red algae of the genera Polysiphonia, Rhodomela, and Ceramium are regularly washed up on beaches of the central Baltic Sea. As the algal masses start to decay, red coloured effluents leak into the water, and this tinge may be traced several hundred meters off shore. In this study, possible toxic effects of these effluents were tested on littoral organisms from different trophic levels. Effects on fertilisation, germination and juvenile survival of the brown seaweed Fucus vesiculosus were investigated, and mortality tests were performed on the crustaceans Artemia salina and Idotea baltica, as well as on larvae and adults of the fish Pomatoschistus microps. Fucus vesiculosus was the most sensitive species of the tested organisms to the red algal extract. The survival of F. vesiculosus recruits was reduced with 50% (LC50) when exposed to a concentration corresponding to 1.7 g l(-1) dw red algae. The lethal concentration for L baltica, A. salina and P. microps were approximately ten times higher. The toxicity to A. salina was reduced if the algal extract was left to decompose during two weeks but the decline in toxicity was not affected by different light or temperature conditions. This study indicates that the filamentous red algae in the central Baltic Sea may produce and release compounds with negative effects on the littoral ecosystem. The effects may be particularly serious for the key species F. vesiculosus, which reproduce in autumn when filamentous red algal blooms are most severe. (C) 2004 Elsevier Ltd. All rights reserved.
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| 10. |
- Karlsson, L. S., et al.
(författare)
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Structural Characterisation of GaP <111 > B Nanowires by HRTEM
- 2008
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Ingår i: Microscopy of Semiconducting Material 2007. - 0930-8989. - 9781402086144 ; 120, s. 229-232
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Konferensbidrag (refereegranskat)abstract
- GaP < 111 > B nanowires are dominated by (111) twins orthogonal to the growth direction and show well-developed {111} side-facets. Based on this, a 3D-model has been constructed with a cross-section of an octahedron used as a building block. The twins can be of ortho- or para type i.e. by 60 degrees about the growth axis or 180 degrees in the twin plane. The segment thickness variation follows an exponential distribution with a clear dependence oil growth ternperature. Multislice simulations show different features of the twin types that are useful for further characterisation.
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