| 51. |
- Ackerley, Rochelle, 1980, et al.
(författare)
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Case Studies in Neuroscience: Sensations elicited and discrimination ability from nerve cuff stimulation in an amputee over time
- 2018
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Ingår i: Journal of Neurophysiology. - : American Physiological Society. - 0022-3077 .- 1522-1598. ; 120:1, s. 291-295
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Tidskriftsartikel (refereegranskat)abstract
- The present case study details sensations elicited by electrical stimulation of peripheral nerve axons using an implanted nerve cuff electrode, in a participant with a transhumeral amputation. The participant uses an osseointegrated electromechanical interface, which enables skeletal attachment of the prosthesis and long-term, stable, bidirectional communication between the implanted electrodes and prosthetic arm. We focused on evoking somatosensory percepts, where we tracked and quantified the evolution of perceived sensations in the missing hand. which were evoked from electrical stimulation of the nerve, for over 2 yr. These sensations included small, pointlike areas of either vibration or pushing, to larger sensations over wider areas, indicating the recruitment of a few and many afferents, respectively. Furthermore, we used a two-alternative forced choice paradigm to measure the level of discrimination between trains of brief electrical stimuli, to gauge what the participant could reliably distinguish between. At best, the participant was able to distinguish a 05-Hz difference and on average acquired a 3.8-Hz just-noticeable difference at a more stringent psychophysical level. The current work shows the feasibility for long-term sensory feedback in prostheses, via electrical axonal stimulation, where small and relatively stable percepts were felt that may be used to deliver graded sensory feedback. This opens up opportunities for signaling feedback during movements (e.g., for precision grip), but also for conveying more complex cutaneous sensations. such as texture. NEW & NOTEWORTHY We demonstrate the long-term stability and generation of sensations from electrical peripheral nerve stimulation in an amputee. through an osseointegrated implant. We find that perceived tactilelike sensations could be generated for over 2 yr. in the missing hand. This is useful for prosthetic development and the implementation of feedback in artificial body parts.
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| 52. |
- Adalbjornsson, S. I., et al.
(författare)
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Estimating Periodicities in Symbolic Sequences Using Sparse Modeling
- 2015
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Ingår i: Ieee Transactions on Signal Processing. - : Institute of Electrical and Electronics Engineers (IEEE). - 1053-587X .- 1941-0476. ; 63:8, s. 2142-2150
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we propose a method for estimating statistical periodicities in symbolic sequences. Different from other common approaches used for the estimation of periodicities of sequences of arbitrary, finite, symbol sets, that often map the symbolic sequence to a numerical representation, we here exploit a likelihood-based formulation in a sparse modeling framework to represent the periodic behavior of the sequence. The resulting criterion includes a restriction on the cardinality of the solution; two approximate solutions are suggested-one greedy and one using an iterative convex relaxation strategy to ease the cardinality restriction. The performance of the proposed methods are illustrated using both simulated and real DNA data, showing a notable performance gain as compared to other common estimators.
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| 53. |
- Adamovic, Svetlana, 1965, et al.
(författare)
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Association study of IL2/IL21 and FcgRIIa: significant association with the IL2/IL21 region in Scandinavian coeliac disease families
- 2008
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Ingår i: Genes and immunity. - : Springer Science and Business Media LLC. - 1466-4879 .- 1476-5470. ; 9:4, s. 364-367
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Tidskriftsartikel (refereegranskat)abstract
- The first genome-wide association study performed in a UK coeliac disease (CD) case-control cohort revealed association with a linkage disequilibrium block containing the KIAA1109/Tenr/IL2/IL21 genes. Also recently, an association with a non-synonymous polymorphism in Fcitalic gammaRIIa (CD32a) was reported in CD with an unusually strong P-value. We aimed to replicate the reported associations with the single nucleotide polymorphisms rs13119723 A>G and rs6822844 G>T in the KIAA1109/Tenr/IL2/IL21 region and rs1801274 G>A in the Fcitalic gammaRIIa gene in a family sample consisting of 325 Swedish/Norwegian families using the robust transmission disequilibrium test. The family sample used in this study included 100 families with two or more children affected by CD and 225 families with one affected child. We could confirm significant association between the polymorphisms rs13119723 A>G and rs6822844 G>T located in the KIAA1109/Tenr/IL2/IL21 region and CD (P-value 0.001 and 0.002, respectively). However, we found no association with the Fcitalic gammaRIIa rs1801274 G>A polymorphism (P-value=0.3). In conclusion, our results support the KIAA1109/Tenr/IL2/IL21 region as a true CD susceptibility region.
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| 54. |
- Adamovic, Svetlana, 1965, et al.
(författare)
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Fine mapping study in Scandinavian families suggests association between coeliac disease and haplotypes in chromosome region 5q32.
- 2008
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Ingår i: Tissue Antigens. - : Wiley. - 1399-0039 .- 0001-2815. ; 71:1, s. 27-34
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Tidskriftsartikel (refereegranskat)abstract
- The previous genome-wide scan in Scandinavian families supported earlier evidence for linkage of a region on chromosome 5 (5q31–33) to coeliac disease. This study deals with further genetic mapping of an 18 cM region, spanning from marker GAh18A (131.87 Mb) to D5S640 (149.96 Mb). Linkage and association analyses were performed in a two-step approach. First, seven microsatellites were added. Strong evidence for linkage was obtained with a Zlr score of 3.96, Pnc = 4 × 10−5 at marker D5S436. The strongest association was with a haplotype consisting of the markers D5S2033 and D5S2490 (Pnc < 0.001). In the second step, we added 17 microsatellites and 69 single nucleotide polymorphisms (SNPs) to the analysis. These markers were located close to or within candidate genes across the region of approximately 7 Mb beneath the linkage peak marked by D5S2017 and D5S812. A substantial increase of the linkage signal with a maximum Zlr score of 4.6 at marker rs1972644 (Pnc = 2 × 10−6) was obtained and several SNPs showed association. Seven SNPs that individually showed the strongest association were genotyped in a second independent family sample set (225 trios). In the trio family sample as well as in the multiplex family sample, the strongest association was found with SNPs within the region flanked by the associated microsatellites D5S2033 and D5S2490 at 5q32.
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| 55. |
- Adams, Kelly L., et al.
(författare)
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In Vitro Electrochemistry of Biological Systems
- 2008
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Ingår i: Annual Reviews of Analytical Chemistry. - : Annual Reviews. - 1936-1327 .- 1936-1335. ; 1, s. 329-355
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Tidskriftsartikel (refereegranskat)abstract
- This article reviews recent work involving electrochemical methods for in vitro analysis of biomolecules, with an emphasis on detection and manipulation at and of single cells and cultures of cells. The techniques discussed include constant potential amperometry, chronoamperometry, cellular electroporation, scanning electrochemical microscopy, and microfluidic platforms integrated with electrochemical detection. The principles of these methods are briefly described, followed in most cases with a short description of an analytical or biological application and its significance. The use of electrochemical methods to examine specific mechanistic issues in exocytosis is highlighted, as a great deal of recent work has been devoted to this application.
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| 56. |
- Adams, Kelly L., et al.
(författare)
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Steady-State Electrochemical Determination of Lipidic Nanotube Diameter Utilizing an Artificial Cell Model
- 2010
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 1520-6882 .- 0003-2700. ; 82:3, s. 1020-1026
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Tidskriftsartikel (refereegranskat)abstract
- By exploiting the capabilities of steady-state electrochemical measurements, we have measured the inner diameter of a lipid nanotube using Fick’s first law of diffusion in conjunction with an imposed linear concentration gradient of electroactive molecules over the length of the nanotube. Fick’s law has been used in this way to provide a direct relationship between the nanotube diameter and the measurable experimental parameters Δi (change in current) and nanotube length. Catechol was used to determine the Δi attributed to its flux out of the nanotube. Comparing the nanotube diameter as a function of nanotube length revealed that membrane elastic energy was playing an important role in determining the size of the nanotube and was different when the tube was connected to either end of two vesicles or to a vesicle on one end and a pipet tip on the other. We assume that repulsive interaction between neck regions can be used to explain the trends observed. This theoretical approach based on elastic energy considerations provides a qualitative description consistent with experimental data.
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| 57. |
- Adawi, Tom, 1970, et al.
(författare)
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Characterizing Software Engineering Students' Discussions during Peer Instruction : Opportunities for Learning and Implications for Teaching
- 2016
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Ingår i: International Journal of Engineering Education. - 0949-149X. ; 32:2, s. 927-936
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Tidskriftsartikel (refereegranskat)abstract
- Peer instruction is a method for activating students during lectures, which has gained a considerable amount of attention in higher education due to claims of dramatic improvement in learning gains. The purpose of this qualitative research study is to investigate what types of discussions engineering students engage in during a peer instruction session and what learning possibilities that are enabled by these different types of discussions. We observed twelve students during six separate and simulated peer instruction sessions and the students were interviewed individually after the sessions.Ananalysis of the data revealed that the students engaged in three qualitatively different types of discussions: affirmative discussions, motivating discussions, and argumentative discussions. We characterize these different types of discussions in terms of the number of alternative answers the students discuss, the extent to which they draw on prior knowledge and experiences, as well as the fundamental difference between an explanation and an argument. A good opportunity for learning is opened up when students are aspiring to find the truth, not simply being satisfied with what they believe to be true. We conclude that students do not always engage in discussions that support their learning in the best way, and we discuss implications for using peer instruction as a teaching method.
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| 58. |
- Adelfio, Marco, 1980, et al.
(författare)
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Translating ‘New Compactism’, circulation of knowledge and local mutations: Copenhagen’s Sydhavn as a case study
- 2022
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Ingår i: International Planning Studies. - : Informa UK Limited. - 1469-9265 .- 1356-3475. ; 27:2, s. 173-195
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Tidskriftsartikel (refereegranskat)abstract
- The international circulation of urban design concepts often leads to their characterization as transferable ideals defined by a set of universalized ‘best practices’ that are simply implemented in new localities, as is typical of top-down approaches to planning. Recently, the compact city and New Urbanism have become trendy concepts informing the development of urban projects across geographies. This research draws on ANT sensitivities and policy mobilities studies to examine the regeneration of Copenhagen’s Southern Harbour (Sydhavn) wherein the compact city and New Urbanism ideals, together with a declared inspiration from Dutch architecture, were originally incorporated in the masterplan. Through the analysis of documents and semi-structured interviews, the paper illustrates how these ideals–merged as 'New Compactism'–were mobilized and re-intepreted by local actors in Sydhavn. It thus adds to our understanding of how the circulation of such ideals is not a matter of implementation, but a complex social process of translation that entails struggle and transformation.
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| 59. |
- Adermark, Louise, 1974, et al.
(författare)
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Age-contingent influence over accumbal neurotransmission and the locomotor stimulatory response to acute and repeated administration of nicotine in Wistar rats
- 2015
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Ingår i: Neuropharmacology. - : Elsevier BV. - 0028-3908. ; 97, s. 104-112
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Tidskriftsartikel (refereegranskat)abstract
- Nicotine addiction is one of the leading contributors to the global burden of disease, and early onset smokers report a more severe addiction with lower chance of cessation than those with a late onset. Preclinical research supports an age-dependent component to the rewarding and reinforcing properties of nicotine, and the aim of this study was to. define behavioral adaptations and changes in accumbal neurotransmission that arise over 15 days of intermittent nicotine treatment (0.36 mg/kg/day) in rats of three different ages (5 weeks, 10 weeks, 36 weeks old). Repeated treatment increased the locomotor stimulatory response to nicotine in all age groups, but significantly faster in the two younger groups. In addition, nicotine decreased rearing activity in a way that sustained even after repeated administration in aged rats but not in the younger age groups. Electrophysiological field potential recordings revealed a decline in input/output function in the nucleus accumbens (NAc) of animals intermittently treated with nicotine starting at 5 weeks of age, but not in older animals. In drug naive rats, acute administration of nicotine modulated both accumbal dopamine output and excitatory transmission in a partially age dependent manner. Fifteen days of intermittent nicotine treatment did not alter the acute effect displayed by nicotine on dopamine levels or evoked field potentials. The data presented here show that both acute and repeated nicotine administration modulates accumbal neurotransmission and behavior in an age-contingent manner and that these age-dependent differences could reflect important neurobiological underpinnings associated with the increased vulnerability for nicotine-addiction in adolescents. (C) 2015 Elsevier Ltd. All rights reserved.
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| 60. |
- Adermark, Louise, 1974, et al.
(författare)
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Ethanol acutely decreases astroglial gap junction permeability in primary cultures from defined brain regions
- 2004
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Ingår i: Neurochemistry International. - : Elsevier BV. - 0197-0186. ; 45:7, s. 971-978
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Tidskriftsartikel (refereegranskat)abstract
- The acute effect of hyperosmotic ethanol on gap junction permeability was examined in astroglial cells in primary culture from five different brain regions. Gap junction permeability was analyzed by measuring dye spreading from cell to cell with the low molecular weight dye Lucifer Yellow. Ethanol concentrations 25-300 mM significantly decreased dye spreading in cultures from the cerebral cortex in a dose-dependent but time-independent manner for up to 60 min. Besides cerebral cortex, exposure to 150 mM ethanol decreased dye spreading in astroglial cultures from the hippocampus and from the brain stem, while cultures from the olfactory bulb and from the hypothalamus were not significantly affected. The ethanol-induced decrease in dye spreading in cultures from the cerebral cortex was not mediated through changes in cell volume, osmolarity, protein kinase C (PKC) phosphorylation, intracellular pH, or intracellular calcium concentration ([Ca 2+ ] i ). The decrease in dye spreading was abolished upon incubation in sodium-reduced buffer, and after blockage of the Na + /K + /2Cl - cotransporter with furosemide. The results presented here indicate that ethanol-mediated decrease in dye spreading is directly or indirectly dependent on sodium. © 2004 Elsevier Ltd. All rights reserved.
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