| 1. |
- Håkanson, Ulf, et al.
(författare)
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Single InP/GaInP quantum dots studied by scanning tunneling microscopy and scanning tunneling microscopy induced luminescence
- 2002
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 80:3, s. 494-496
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Tidskriftsartikel (refereegranskat)abstract
- We have studied the optical and structural properties of single, self-assembled InP quantum dots (QDs) overgrown with nominally 5 nm of GaInP, using an ultrahigh-vacuum scanning tunneling microscope (STM) operating at low temperatures. The STM is combined with an optical detection system, which allows us to detect the emission from individual quantum dots with high spatial resolution. We find that the InP QDs act as nucleation points for the GaInP overgrowth, where the strain induced by the overlayer give rise to a QD emission around 1.46 eV. (C) 2002 American Institute of Physics.
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| 2. |
- Johansson, Curt R, et al.
(författare)
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Participation and empowerment by visualisation
- 2004
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Ingår i: Applied participation and empowerment at work - methods, tools and case studies. - 9789144038308 ; , s. 53-79
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 3. |
- Johansson, Mikael, et al.
(författare)
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Correlation between overgrowth morphology and optical properties of single self-assembled InP quantum dots
- 2003
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Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 68:12
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Tidskriftsartikel (refereegranskat)abstract
- We have studied the early stages of GaInP overgrowth on InP quantum dots (QD's) experimentally and theoretically. A direct correlation between the surface morphology and the optical properties of individual InP QD's is made using scanning tunneling microscopy (STM) and scanning tunneling luminescence. The geometric structure of the islands is further investigated using cross-sectional transmission electron microscopy (TEM). The overgrowth occurs in three stages; initially the InP QD's act as seeding points for the overgrowth, where the GaInP grows laterally from the side facets of the QD. The growth occurs preferentially in the [110] direction and elongated GaInP/InP islands are formed. As the overgrowth continues the islands increase laterally in size and GaInP also starts to grow between the islands, but not covering the top of the InP QD's. The growth of GaInP on top of the QD's commences once the islands have begun to coalesce. Using a model based on the STM and TEM results the electronic structures of the QD's have been calculated by eight-band k.p theory. The calculations are in good agreement with the experimental results. Our findings unravel the details of the strain induced energy shift of the QD luminescence previously reported [Pistol , Appl. Phys. Lett. 67, 1438 (1995)].
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| 4. |
- Kadi, Fawzi, et al.
(författare)
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Effects of one bout of endurance exercise on the expression of myogenin in human quadriceps muscle
- 2004
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Ingår i: Histochemistry and Cell Biology. - : Springer Science and Business Media LLC. - 0948-6143 .- 1432-119X. ; 121:4, s. 329-334
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to investigate the cellular localisation of MyoD and myogenin in human skeletal muscle fibres as well as the possible alterations in the expression of MyoD and myogenin in response to a single bout of endurance exercise at 40% and 75% of maximum oxygen uptake (VO(2) max). Twenty-five biopsies (5 per subject) from the vastus lateralis muscle were obtained before exercise, from the exercising leg at 40% and 75% of VO(2) max and from the resting leg following these exercise bouts. The tyramide signal amplification-direct and the Vectastain ABC methods using specific monoclonal antibodies were used to determine the exact location of myogenin and MyoD, to identify muscle satellite cells and to determine myosin heavy chain (MyHC) composition. At rest, myonuclei did not express MyoD or myogenin. Following a single bout of exercise at 40% and 75% of VO(2) max, an accumulation of myogenin in myonuclei and not in satellite cells was observed in biopsies from the exercised leg but not in biopsies before exercise and from the resting leg. The number of myogenin-positive myonuclei varied among individuals indicating differences in the response to a single exercise bout. In conclusion, this immunohistochemical study showed that a rapid rearrangement of myogenin expression occurs in exercised human skeletal muscles in response to a single bout of exercise.
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| 5. |
- Lilliehorn, Tobias, et al.
(författare)
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Array transducer for ultrasonic manipulation of particles
- 2004
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Ingår i: ; , s. 69-72
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper presents the concept and initial work on a microfluidic platform for bead-based analysis of biological sample. The core technology in this project is ultrasonic manipulation and trapping of particle in array configurations by means of acoustic forces. The platform is ultimately aimed for parallel multistep bioassays performed on biochemically activated microbeads (or particles) using submicrolitre sample volumes. A first prototype with three individually controlled particle trapping sites has been developed and evaluated. Standing ultrasonic waves were generated across a microfluidic channel by integrated PZT ultrasonic microtransducers. Particles in a fluid passing a transducer were drawn to pressure minima in the acoustic field, thereby being trapped and confined laterally over the transducer. It is anticipated that acoustic trapping using integrated transducers can be exploited in miniaturised total chemical analysis systems (µTAS), where e.g. microbeads with immobilised antibodies can be trapped in arrays and subjected to minute amounts of sample followed by a reaction, detected using fluorescence. A first model bioassay with detection of fluorescein marked avidin binding to trapped biotin beads has been evaluated. To enable development of the next generation of 2D array trapping devices, means of microfabricating multilayer ultrasonic array transducers using thick film technology have been developed.
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