| 11. |
- Aghaeipour, Mahtab, et al.
(författare)
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Enhanced optical absorption in nanowires over a desire range of wavelengths
- 2017
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Ingår i: MOC2017 : technical digest of the Twenty-Second Microoptics Conference. - : IEEE. - 9784863486096 - 9781509049240 ; , s. 360-361
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Konferensbidrag (refereegranskat)abstract
- Engineering optical absorption in nanowires, over a desire range of wavelengths is of importance to design high-performance nanowire-based photovoltaics. To this end, we integrate the nanowires with distributed Bragg reflectors to enhance absorption spectra of the nanowires and relate the consequent enhancement to increasing the optical path lengths of the modes. © 2017 The Japan Society of Applied Physics.
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| 12. |
- Aghaeipour, Mahtab
(författare)
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Tailoring the Optical Response of III-V Nanowire Arrays
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Semiconductor nanowires show a great deal of promise for applications in a wide range of important fields, including photovoltaics, biomedicine, and information technology. Developing these exciting applications is strongly dependent on understanding the fundamental properties of nanowires, such as their optical resonances and absorption spectra. In this thesis we explore optical absorption spectra of arrays of vertical III-V nanowires with a special emphasis on structures optimized to enhance absorption in the solar spectrum. First, we analyze experimentally determined absorption spectra of both indium phosphide (InP) and gallium phosphide (GaP) nanowire arrays. The study provides an intuitive understanding of how the observed absorption resonances in the nanowires may be tuned as a function of their geometrical parameters and crystal structure. As a consequence, the spectral position of absorption resonances can be precisely controlled through the nanowire diameter. However, the results highlight how the blue-shift in the optical absorption resonances as the diameter of the nanowires decreases comes to a halt at low diameters. The stop point is related to the behavior of the refractive indices of the nanowires. The wavelength of the stop is different for nanowire polytypes of similar dimensions due to differences in their refractive indices. We then present a theoretical argument that it is important to consider symmetry properties when tailoring the optical modes excited in the nanowires for enhanced absorption. We show that absorption spectra may be enhanced compared to vertical nanowires at normal incidence by tilting the nanowires with normal incidence light, or by using off-normal incidence with vertical nanowires. This is because additional optical modes inside the nanowires are excited when the symmetry is broken. Looking forward to omnidirectional applications, we consider branched nanowires as a way to enhance the absorption spectra at normal incidence by taking advantage of simultaneous excitation of the spectrally different optical modes in the branches and the stems. Third, we describe in theoretical terms how integrating distributed Bragg reflectors (DBRs) with the nanowires can improve absorption spectra compared to conventional nanowires. DBRs provide a way to employ light trapping mechanisms which increases the optical path length of the excited modes and thereby improves the absorption of the excited modes. At normal incidence, DBR-nanowires improve the absorption efficiency to 78%, compared to 72% for conventional nanowires. We show that the efficiency is increased to 85% for an off-normal incident angle of 50˚. Overall, our results show that studies of optical resonances in nanowires that take the light-matter interaction into account provide opportunities to develop novel optical and optoelectronic functionalities in nanoscience and nanotechnology.
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| 13. |
- Ahlqvist, Emma, et al.
(författare)
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High-resolution mapping of a complex disease, a model for rheumatoid arthritis, using heterogeneous stock mice
- 2011
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Ingår i: Human Molecular Genetics. - Oxford : Oxford University Press. - 0964-6906 .- 1460-2083. ; 20:15, s. 3031-3041
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Tidskriftsartikel (refereegranskat)abstract
- Resolving the genetic basis of complex diseases like rheumatoid arthritis will require knowledge of the corresponding diseases in experimental animals to enable translational functional studies. Mapping of quantitative trait loci in mouse models of arthritis, such as collagen-induced arthritis (CIA), using F(2) crosses has been successful, but can resolve loci only to large chromosomal regions. Using an inbred-outbred cross design, we identified and fine-mapped CIA loci on a genome-wide scale. Heterogeneous stock mice were first intercrossed with an inbred strain, B10.Q, to introduce an arthritis permitting MHCII haplotype. Homozygous H2(q) mice were then selected to set up an F(3) generation with fixed major histocompatibility complex that was used for arthritis experiments. We identified 26 loci, 18 of which are novel, controlling arthritis traits such as incidence of disease, severity and time of onset and fine-mapped a number of previously mapped loci. © The Author 2011. Published by Oxford University Press. All rights reserved.
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| 14. |
- Ahlström, Gerd, et al.
(författare)
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Ageing people with intellectual disabilities and the association between frailty factors and social care : A Swedish national register study
- 2022
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Ingår i: Journal of Intellectual Disabilities. - Thousand Oaks, CA : Sage Publications. - 1744-6295 .- 1744-6309. ; 26:4, s. 900-918
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to describe the social care provided for different age groups of people with intellectual disability, 55 years or above, and to investigate the association between such care and frailty factors for those with diagnosed level of intellectual disabilities. Descriptive and logistic regression analyses were used. Commonest forms of social care among the 7936 people were Residential care, Daily activities and Contact person. Home help and Security alarm increased with age. The frailty factors significantly associated with increased social care were age, polypharmacy and severe levels of intellectual disabilities. Persons most likely to be in residential care were in the age group 65–79 with polypharmacy and severe disability. The results indicate a need for further research of how frailty factors are considered in social care and longstanding medication, especially then severe intellectual disability hinders communication. A national strategic plan for preventive interventions should be developed to ensure the best possible healthy ageing. © The Author(s) 2021.
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| 15. |
- Aksel Jacobsen, Freja, et al.
(författare)
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A Role for the Non-Receptor Tyrosine Kinase Abl2/Arg in Experimental Neuroinflammation
- 2018
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Ingår i: Journal of Neuroimmune Pharmacology. - New York, NY : Springer-Verlag New York. - 1557-1890 .- 1557-1904. ; 13:2, s. 265-276
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Tidskriftsartikel (refereegranskat)abstract
- Multiple sclerosis is a neuroinflammatory degenerative disease, caused by activated immune cells infiltrating the CNS. The disease etiology involves both genetic and environmental factors. The mouse genetic locus, Eae27, linked to disease development in the experimental autoimmune encephalomyelitis (EAE) model for multiple sclerosis, was studied in order to identify contributing disease susceptibility factors and potential drug targets for multiple sclerosis. Studies of an Eae27 congenic mouse strain, revealed that genetic variation within Eae27 influences EAE development. The Abl2 gene, encoding the non-receptor tyrosine kinase Arg, is located in the 4,1 megabase pair long Eae27 region. The Arg protein plays an important role in cellular regulation and is, in addition, involved in signaling through the B- and T-cell receptors, important for the autoimmune response. The presence of a single nucleotide polymorphism causing an amino acid change in a near actin-interacting domain of Arg, in addition to altered lymphocyte activation in the congenic mice upon immunization with myelin antigen, makes Abl2/Arg a candidate gene for EAE. Here we demonstrate that the non-synonymous SNP does not change Arg’s binding affinity for F-actin but suggest a role for Abl kinases in CNS inflammation pathogenesis by showing that pharmacological inhibition of Abl kinases ameliorates EAE, but not experimental arthritis. © 2018 The Author(s)
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| 16. |
- Alabdallah, Abdallah, 1979-, et al.
(författare)
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The Concordance Index decomposition : A measure for a deeper understanding of survival prediction models
- 2024
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Ingår i: Artificial Intelligence in Medicine. - Amsterdam : Elsevier B.V.. - 0933-3657 .- 1873-2860. ; 148
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Tidskriftsartikel (refereegranskat)abstract
- The Concordance Index (C-index) is a commonly used metric in Survival Analysis for evaluating the performance of a prediction model. In this paper, we propose a decomposition of the C-index into a weighted harmonic mean of two quantities: one for ranking observed events versus other observed events, and the other for ranking observed events versus censored cases. This decomposition enables a finer-grained analysis of the relative strengths and weaknesses between different survival prediction methods. The usefulness of this decomposition is demonstrated through benchmark comparisons against classical models and state-of-the-art methods, together with the new variational generative neural-network-based method (SurVED) proposed in this paper. The performance of the models is assessed using four publicly available datasets with varying levels of censoring. Using the C-index decomposition and synthetic censoring, the analysis shows that deep learning models utilize the observed events more effectively than other models. This allows them to keep a stable C-index in different censoring levels. In contrast to such deep learning methods, classical machine learning models deteriorate when the censoring level decreases due to their inability to improve on ranking the events versus other events.
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| 17. |
- Albinsson, John, et al.
(författare)
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Combined use of Iteration, Quadratic Interpolation and an Extra Kernel for high-resolution 2D particle tracking : a first evaluation
- 2010
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Ingår i: 2010 ieee international ultrasonics symposium. - New York : IEEE Press. - 9781457703829 ; , s. 2000-2003
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Konferensbidrag (refereegranskat)abstract
- A novel 2D particle tracking method, that uses 1) iteration, 2) fast quadratic sub-pixel estimation (with only 28 multiplications per movement), and 3) a previous kernel, has been evaluated and compared with a full-search block-matching method. The comparison with high-frequency ultrasound data (40 MHz) was conducted in silico and on phantoms, which comprised lateral, diagonal, and ellipsoidal movement patterns with speeds of 0–15 mm/s. The mean tracking error was reduced by 68% in silico and 71% for the phantom measurements. When only sub-pixel estimation was used, the decrease in the tracking error was 61% in silico and 57% for the phantom measurements. As well as decreasing the tracking error, the new method only used 70% of the computational time needed by the full-search block-matching method. With a fast method having good tracking ability for high-frequency ultrasound data, we now have a tool to better investigate tissue movements and its dynamic functionality.
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| 18. |
- Albinsson, John, et al.
(författare)
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Improved tracking performance of lagrangian block-matching methodologies using block expansion in the time domain : In silico, phantom and invivo evaluations
- 2014
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Ingår i: Ultrasound in Medicine and Biology. - : Elsevier. - 0301-5629 .- 1879-291X. ; 40:10, s. 2508-2520
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to evaluate tracking performance when an extra reference block is added to a basic block-matching method, where the two reference blocks originate from two consecutive ultrasound frames. The use of an extra reference block was evaluated for two putative benefits: (i) an increase in tracking performance while maintaining the size of the reference blocks, evaluated using in silico and phantom cine loops; (ii) a reduction in the size of the reference blocks while maintaining the tracking performance, evaluated using in vivo cine loops of the common carotid artery where the longitudinal movement of the wall was estimated. The results indicated that tracking accuracy improved (mean - 48%, p<0.005 [in silico]; mean - 43%, p<0.01 [phantom]), and there was a reduction in size of the reference blocks while maintaining tracking performance (mean - 19%, p<0.01 [in vivo]). This novel method will facilitate further exploration of the longitudinal movement of the arterial wall. (C) 2014 World Federation for Ultrasound in Medicine & Biology.
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| 19. |
- Ali, Lilas, 1981, et al.
(författare)
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Caring Situation, Health, Self-efficacy, and Stress in Young Informal Carers of Family and Friends with Mental Illness in Sweden
- 2015
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Ingår i: Issues in Mental Health Nursing. - New York, NY : Informa UK Limited. - 0161-2840 .- 1096-4673. ; 36:6, s. 407-415
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Tidskriftsartikel (refereegranskat)abstract
- This study compared the caring situation, health, self-efficacy, and stress of young (16-25) informal carers (YICs) supporting a family member with mental illness with that of YICs supporting a friend. A sample of 225 carers, assigned to a family group (n = 97) or a friend group (n = 128) completed the questionnaire. It was found that the family group experiences a lower level of support and friends experienced a lower positive value of caring. No other differences in health, general self-efficacy and stress were found. YICs endure different social situations, which is why further study of the needs of YICs, especially those supporting friends, is urgently needed.
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| 20. |
- Ali, Lilas, 1981, et al.
(författare)
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Effectiveness of web-based versus folder support interventions for young informal carers of persons with mental illness: A randomized controlled trial
- 2014
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Ingår i: Patient Education and Counseling. - Shannon, Irland : Elsevier BV. - 0738-3991 .- 1873-5134. ; 94:3, s. 362-371
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Compare the impact of two interventions, a web-based support and a folder support, for young persons who care for people who suffer from mental illness. Methods: This study was a randomized control trial, following the CONSORT statements, which compared the impact of two interventions. Primary outcome variable was stress, and secondary outcome variables were caring situation, general self-efficacy, well-being, health, and quality of life of young informal carers (N= 241). Data were collected in June 2010 to April 2011, with self-assessment questionnaires, comparing the two interventions and also to detect changes. Results: The stress levels were high in both groups at baseline, but decreased in the folder group. The folder group had improvement in their caring situation (also different from the web group), general self-efficacy, well-being, and quality of life. The web group showed increase in well-being. Conclusion: Young informal carers who take on the responsibility for people close to them; suffer consequences on their own health. They live in a life-situation characterized by high stress and low well-being. This signals a need for support. Practice implications: The non-significant differences show that each intervention can be effective, and that it depends upon the individual's preferences. This highlights the importance of adopting person-centered approach, in which young persons can themselves choose support strategy. © 2013 Elsevier Ireland Ltd.
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