| 1. |
- Höglund, Linda, 1974-, et al.
(författare)
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Bias and temperature dependence of the escape processes in quantum dots-in-a-well infrared photodetectors
- 2008
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Ingår i: Applied Physics Letters. - New York : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 93:10, s. 103501-
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Tidskriftsartikel (refereegranskat)abstract
- The performance of quantum dots-in-a-well infrared photodetectors (DWELL IPs) has been studied by means of interband and intersubband photocurrent measurements as well as dark current measurements. Using interband photocurrent measurements, substantial escape of electrons from lower lying states in the DWELL structure at large biases was revealed. Furthermore, a significant variation in the escape probability from energy states in the DWELL structure with applied bias was observed. These facts can explain the strong temperature and bias dependence of both photocurrent and dark currents in DWELL IPs.
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| 2. |
- Sjöquist, Emma S., et al.
(författare)
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Physical Activity Coaching of Patients with Rheumatoid Arthritis in Everyday Practice : A Long-term Follow-up
- 2011
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Ingår i: Musculoskeletal Care. - Chichester : John Wiley & Sons. - 1478-2189 .- 1557-0681. ; 9:2, s. 75-85
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To investigate the long-term effects on perceived general health, disease activity, pain, activity limitation and cognitive behavioural factors of a one-year coaching programme performed in ordinary physical therapy practice to promote the adoption of health-enhancing physical activity in patients with early rheumatoid arthritis (RA).METHODS: A total of 228 patients with early RA, from 10 rheumatology clinics in Sweden, were randomly assigned to an intervention group (IG; n = 94) or a control group (CG; n = 134). The IG was coached by physical therapists during the first year to adopt health-enhancing levels of physical activity (30 minutes/day, moderately intensive, ≥ 4 days/week). No coaching was given during the subsequent year between post-intervention and follow-up. Follow-up assessment consisted of a postal questionnaire on physical activity and of visual analogue scales for ratings of general health perception and pain. The Health Assessment Questionnaire Disability Index (HAQ) and the Disease Activity Score in 28 joints (DAS 28) were collected at regular medical check-ups.RESULTS: Sixty-five (69%) participants in the IG and 92 (69%) in the CG completed the entire study period by filling in the follow-up questionnaire on physical activity two years after baseline. The intervention seemed to lack any significant influence on long-term outcome. However, different patterns of change in physical activity behaviour were observed in the two groups.CONCLUSIONS: No long-term improvement in perceived general health or other outcomes were found in the follow-up. This may partly be because the intervention lacked several important behavioural elements for physical activity maintenance. Copyright © 2011 John Wiley & Sons, Ltd.
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| 3. |
- Andersson, Maria L.E. 1968-, et al.
(författare)
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Baseline levels of circulating galectin-1 associated with radiographic hand but not radiographic knee osteoarthritis at a two-year follow-up
- 2024
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Ingår i: Osteoarthritis and Cartilage Open. - Oxford : Elsevier. - 2665-9131. ; 6:2
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Tidskriftsartikel (refereegranskat)abstract
- Objective: We tested the potential of circulating galectin-1, interleukin (IL)-1 beta, IL-6, and tumour necrosis factor alpha (TNF alpha) levels at baseline in individuals with knee pain as biomarkers for development of radiographic knee and/or hand osteoarthritis (OA). Design: This study comprised 212 individuals with knee pain from the Halland osteoarthritis cohort (HALLOA). Clinical characteristics and serum/plasma levels of galectin-1, IL-1 beta, IL-6, and TNF alpha were measured at baseline, and knee and hand radiographs were obtained at a two-year follow-up. The predictive value of circulating inflammatory markers and clinical variables at baseline was assessed using multinominal logistic regression for those who developed radiographic OA in knees only (n = 25), in hands only (n = 40), and in both knees and hands (n = 43); the group who did not develop OA (n = 104) was used as reference. Correlations were assessed using Spearman's correlation coefficients. Results: As expected, age was identified as a risk factor for having radiographic knee and/or hand OA at the two-year follow-up. Baseline circulating galectin-1 levels did not associate with developing radiographic knee OA but associated with developing radiographic hand OA (odds ratio (OR) for a 20% increased risk: 1.14, 95% confidence interval (CI) 1.01–1.29) and both radiographic knee and hand OA (OR for a 20% increased risk: 1.18, 95% CI 1.05–1.30). However, baseline IL-1 beta, IL-6, and TNF alpha did not associate with developing radiographic knee and/or hand OA. Conclusion: Non-age adjusted circulating galectin-1 is superior to IL-6, IL-1 beta, and TNF alpha in predicting radiographic hand but not knee OA.
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| 4. |
- Andersson, S., et al.
(författare)
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The aphasic person's views of the encounter with other people : a grounded theory analysis
- 2002
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Ingår i: Journal of Psychiatric and Mental Health Nursing. - Oxford : Blackwell. - 1351-0126 .- 1365-2850. ; 9:3, s. 285-292
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Tidskriftsartikel (refereegranskat)abstract
- Notes that being affected by aphasia influences the total life experience. The aim of this study was to generate a theoretical model, from a nursing perspective, of what 12 aphasic persons (aged 28-92 yrs old) experience in encounters with other people. Data were collected through interviews which adopted a biophysical, socio-cultural and psychological approach and then analyzed using grounded theory method. Two main categories emerged, namely: interaction and support. Encountered experiences led to (1) a feeling of having ability, (2) a feeling of being an outsider, and (3) a feeling of dejection or uncertainty. The feeling state was dependent on whether the interaction was obstructed or secure and on whether the support resulted in strengthened or impaired self-esteem. Therefore, nurses need to give support that enhances patients self-esteem and which results in them gaining a positive and realistic view of their aphasia, as well as involving those around them in this perspective. This then will give the possibility for the patient to turn the interaction process from an obstructed into a secure one.
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| 5. |
- Hoglund, L, et al.
(författare)
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Selective optical doping to predict the performance and reveal the origin of photocurrent peaks in quantum dots-in-a-well infrared photodetectors
- 2009
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Ingår i: INFRARED PHYSICS and TECHNOLOGY. - Exeter : Elsevier BV. - 1350-4495 .- 1879-0275. ; 52:6, s. 272-275
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Tidskriftsartikel (refereegranskat)abstract
- Resonant optical pumping across the band gap was used as artificial doping in InAs/In0.15Ga0.85As/GaAs quantum dots-in-a-well infrared photodetectors. Through efficient filling of the quantum dot energy levels by simultaneous optical pumping into the ground states and the excited states of the quantum dots, the response was increased by a factor of 10. Low temperature photocurrent peaks observed at 120 and 148 meV were identified as intersubband transitions emanating from the quantum dot ground state and the quantum dot excited state, respectively by a selective increase of the electron population in the different quantum dot energy levels.
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| 6. |
- Höglund, Linda, 1974-, et al.
(författare)
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Bias mediated tuning of the detection wavelength in asymmetrical quantum dots-in-a-well infrared photodetectors
- 2008
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Ingår i: Applied Physics Letters. - New York : AIP Publishing. - 0003-6951 .- 1077-3118. ; 93:20
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Tidskriftsartikel (refereegranskat)abstract
- Bias-mediated tuning of the detection wavelength within the infrared wavelength region is demonstrated for quantum dots-in-a-well and dots-on-a-well infrared photodetectors. By positioning the InAs quantum dot layer asymmetrically in an 8 nm wide In0.15Ga0.85As/GaAs quantum well, a shift in the peak detection wavelength from 8.4 to 10.3 mu m was observed when reversing the polarity of the applied bias. For a dots-on-a-well structure, the peak detection wavelength was tuned from 5.4 to 8 mu m with small changes in the applied bias. These tuning properties could be essential for applications such as modulators and dual-color infrared detection.
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| 7. |
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| 8. |
- Höglund, Linda, 1974-, et al.
(författare)
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Optical pumping as artificial doping in quantum dots-in-a-well infrared photodetectors
- 2009
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Ingår i: Applied Physics Letters. - New York : AIP Publishing. - 0003-6951 .- 1077-3118. ; 94:5, s. 053503-
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Tidskriftsartikel (refereegranskat)abstract
- Resonant optical pumping across the band gap was used as artificial doping in InAs/In0.15Ga0.85As/GaAs quantum dots-in-a-well infrared photodetectors. By selectively increasing the electron population in the different quantum dot energy levels, the low temperature photocurrent peaks observed at 120 and 148 meV, could be identified as intersubband transitions emanating from the quantum dot ground state and the quantum dot excited state, respectively. With efficient filling of the quantum dot energy levels through simultaneous optical pumping into the ground states and the excited states of the quantum dots, the response was increased by a factor of 10.
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| 9. |
- Höglund, Linda, 1974-, et al.
(författare)
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Origin of photocurrent in lateral quantum dots-in-a-well infrared photodetectors
- 2006
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Ingår i: Applied Physics Letters. - New York : American Institute of Physics. - 0003-6951 .- 1077-3118. ; 88:21
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Tidskriftsartikel (refereegranskat)abstract
- Interband and intersubband transitions of lateral InAs/In0.15Ga0.85As dots-in-a-well quantum dot infrared photodetectors were studied in order to determine the origin of the photocurrent. The main intersubband transition contributing to the photocurrent (PC) was associated with the quantum dot ground state to the quantum well excited state transition. By a comparison between intersubband PC measurements and the energy level scheme of the structure, as deduced from Fourier transform photoluminescence (FTPL) and FTPL excitation spectroscopies, the main transition contributing to the PC was identified.
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| 10. |
- Höglund, Linda, 1974-, et al.
(författare)
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Quantum dots-in-a-well infrared photodetectors for long wavelength infrared detection
- 2006
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Ingår i: Proceedings of SPIE. - Bellingham, Wash. : SPIE - International Society for Optical Engineering. - 9780819464996 ; 6401, s. 1-640109
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Konferensbidrag (refereegranskat)abstract
- We report on a quantum dots-in-a-well infrared photodetector (DWELL QDIP) grown by metal organic vapor phase epitaxy. The DWELL QDIP consisted of ten stacked InAs/In0.5Ga0.85As/GaAs QD layers embedded between n-doped contact layers. The density of the QDs was about 9 × 10 10 cm-2 per QD layer. The energy level structure of the DWELL was revealed by optical measurements of interband transitions, and from a comparison with this energy level scheme the origin of the photocurrent peaks could be identified. The main intersubband transition contributing to the photocurrent was associated with the quantum dot ground state to the quantum well excited state transition. The performance of the DWELL QDIPs was evaluated regarding responsivity and dark current for temperatures between 15 K and 77 K. The photocurrent spectrum was dominated by a LWIR peak, with a peak wavelength at 8.4 μm and a full width at half maximum (FWHM) of 1.1 μm. At an operating temperature of 65 K, the peak responsivity was 30 mA/W at an applied bias of 4 V and the dark current was 1.2×10-5 A/cm2. Wavelength tuning from 8.4 μm to 9.5 μm was demonstrated, by reversing the bias of the detector.
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