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- Akner, Gunnar, 1953-, et al.
(författare)
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Vi står gärna bakom en utfallsbaserad vård
- 2017
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Ingår i: Dagens Samhälle. - 1652-6511.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Jörgen Nordenström försöker få det till att vår kritik av värdebaserad vård egentligen handlar om att vi vill ha mer resurser. Han har helt missuppfattat oss, skriver 26 specialistläkare i en replik.
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| 2. |
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| 3. |
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| 4. |
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| 5. |
- Azarov, Alexander, et al.
(författare)
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Extended defects in ZnO : Efficient sinks for point defects
- 2017
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Ingår i: Applied Physics Letters. - : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 110:2
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Tidskriftsartikel (refereegranskat)abstract
- Dopant-defect reactions dominate the defect formation in mono-crystalline ZnO samples implanted with Ag and B ions. This is in contrast to most other ion species studied and results in an enhanced concentration of extended defects, such as stacking faults and defect clusters. Using a combination of B and Ag implants and diffusion of residual Li atoms as a tracer, we demonstrate that extended defects in ZnO act as efficient traps for highly mobile Zn interstitials. The results imply that dynamic annealing involving interaction of point defects with extended ones can play a key role in the disorder saturation observed for ZnO and other radiation-hard semiconductors implanted with high doses.
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| 6. |
- Azarov, Alexander, et al.
(författare)
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Optical activity and defect/dopant evolution in ZnO implanted with Er
- 2015
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Ingår i: Journal of Applied Physics. - : AMER INST PHYSICS. - 0021-8979 .- 1089-7550. ; 118:12
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Tidskriftsartikel (refereegranskat)abstract
- The effects of annealing on the optical properties and defect/dopant evolution in wurtzite (0001) ZnO single crystals implanted with Er ions are studied using a combination of Rutherford backscattering/channeling spectrometry and photoluminescence measurements. The results suggest a lattice recovery behavior dependent on ion dose and involving formation/evolution of an anomalous multipeak defect distribution, thermal stability of optically active Er complexes, and Er outdiffusion. An intermediate defect band occurring between the surface and ion-induced defects in the bulk is stable up to 900 degrees C and has a photoluminescence signature around 420 nm well corresponding to Zn interstitials. The optical activity of the Er atoms reaches a maximum after annealing at 700 degrees C but is not directly associated to the ideal Zn site configuration, since the Er substitutional fraction is maximal already in the as-implanted state. In its turn, annealing at temperatures above 700 degrees C leads to dissociation of the optically active Er complexes with subsequent outdiffusion of Er accompanied by the efficient lattice recovery.
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| 7. |
- Galeckas, Augustinas, et al.
(författare)
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Investigation of stacking fault formation in hydrogen bombarded 4H-SiC
- 2005
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Ingår i: SILICON CARBIDE AND RELATED MATERIALS 2004. - 0878499636 ; , s. 327-330
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Konferensbidrag (refereegranskat)abstract
- The effects of hydrogen and proton irradiation on stacking fault formation in 4H-SiC are investigated by an optical pump-probe method of imaging spectroscopy. We report optically stimulated nucleation and expansion of stacking faults (SFs) in 0.6 keV H-2(+) implanted n-/n+ and p+/n-/n+ structures. The activation enthalpy for recombination enhanced dislocation glide (REDG) in hydrogenated samples (∼ 0.25 eV) is found to be similar to that in a virgin material. Our results indicate that SFs mainly nucleate at the internal n-/n+ interface, beyond reach of hydrogen, thus justifying minor SF passivation effect. No REDG could be initiated optically in 2.5 MeV proton irradiated samples due to radiation defects providing alternative recombination channels to bypass the REDG mechanism. The radiation damage was verified by DLTS, revealing several new levels below E-C in the range 0.4-0.80 eV, and by PL, showing the onset of D-center related luminescence band and concurrent increase of the nonradiative recombination rate.
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| 9. |
- Hosia, W., et al.
(författare)
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Folding into a ß-Hairpin Can Prevent Amyloid Fibril-Formation
- 2004
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Ingår i: Biochemistry. - : American Chemical Society (ACS). - 0006-2960 .- 1520-4995. ; 43:16, s. 4655-4661
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Tidskriftsartikel (refereegranskat)abstract
- The tetrapeptide KFFE is one of the shortest amyloid fibril-forming peptides described. Herein, we have investigated how the structural environment of this motif affects polymerization. Using a turn motif (YNGK) or a less rigid sequence (AAAK) to fuse two KFFE tetrapeptides, we show by several biophysical methods that the amyloidogenic properties are strongly dependent on the structural environment. The dodecapeptide KFFEAAAKKFFE forms abundant thick fibril bundles. Freshly dissolved KFFEAAAKKFFE is monomeric and shows mainly disordered secondary structure, as evidenced by circular dichroism, NMR spectroscopy, hydrogen/deuterium exchange measurements, and molecular modeling studies. In sharp contrast, the dodecapeptide KFFEYNGKKFFE does not form fibrils but folds into a stable ß-hairpin. This structure can oligomerize into a stable 12-mer and multiples thereof, as shown by size exclusion chromatography, sedimentation analysis, and electrospray mass spectrometry. These data indicate that the structural context in which a potential fibril forming sequence is present can prevent fibril formation by favoring self-limiting oligomerization over polymerization.
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| 10. |
- Janson, Martin S., et al.
(författare)
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Electric-field-assisted migration and accumulation of hydrogen in silicon carbide
- 2000
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 61:11, s. 7195-7198
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Tidskriftsartikel (refereegranskat)abstract
- The diffusion of deuterium (H-2) in epitaxial 4H-SiC layers with buried highly Al-acceptor doped regions has been studied by secondary ion mass spectrometry. H-2 was introduced in the near surface region by the use of 20-keV implantation after which the samples were thermally annealed. As a result, an anomalous accumulation of H-2 in the high doped layers was observed. To explain the accumulation kinetics, a model is proposed where positively charged H-2 ions are driven into the high doped layer and become trapped there by the strong electric field at the edges. This effect is important for other semiconductors as well, since hydrogen is a common impurity present at high concentrations in many semiconductors.
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