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- Semb, G, et al.
(författare)
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Erratum
- 2017
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Ingår i: Journal of plastic surgery and hand surgery. - 2000-6764. ; 51:2, s. 158-158
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Borg, J., et al.
(författare)
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Contribution of non-genetic factors to dopamine and serotonin receptor availability in the adult human brain
- 2016
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Ingår i: Molecular Psychiatry. - London, United Kingdom : Nature Publishing Group. - 1359-4184 .- 1476-5578. ; 51, s. 879-879
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Tidskriftsartikel (refereegranskat)abstract
- The dopamine (DA) and serotonin (5-HT) neurotransmission systems are of fundamental importance for normal brain function and serve as targets for treatment of major neuropsychiatric disorders. Despite central interest for these neurotransmission systems in psychiatry research, little is known about the regulation of receptor and transporter density levels. This lack of knowledge obscures interpretation of differences in protein availability reported in psychiatric patients. In this study, we used positron emission tomography (PET) in a twin design to estimate the relative contribution of genetic and environmental factors, respectively, on dopaminergic and serotonergic markers in the living human brain. Eleven monozygotic and 10 dizygotic healthy male twin pairs were examined with PET and [(11)C]raclopride binding to the D2- and D3-dopamine receptor and [(11)C]WAY100635 binding to the serotonin 5-HT1A receptor. Heritability, shared environmental effects and individual-specific non-shared effects were estimated for regional D2/3 and 5-HT1A receptor availability in projection areas. We found a major contribution of genetic factors (0.67) on individual variability in striatal D2/3 receptor binding and a major contribution of environmental factors (pairwise shared and unique individual; 0.70-0.75) on neocortical 5-HT1A receptor binding. Our findings indicate that individual variation in neuroreceptor availability in the adult brain is the end point of a nature-nurture interplay, and call for increased efforts to identify not only the genetic but also the environmental factors that influence neurotransmission in health and disease.
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| 8. |
- Hedenström, Anders, et al.
(författare)
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Radar Observations of Arctic Bird Migration in the Beringia Region
- 2009
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Ingår i: Arctic. - 0004-0843. ; 62:1, s. 25-37
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Tidskriftsartikel (refereegranskat)abstract
- Bird migration was recorded by tracking radar and visual observations in the Beringia region. The data were subdivided into seven areas extending from north of Wrangel Island southeastward toward the Bering Strait and then northwestward off the coast of Alaska to Point Barrow. The studies, which took place during a ship-based expedition between 30 July and 19 August 2005, recorded a total of 557 tracks (average duration 120 seconds) of bird flocks or individuals on post-breeding migration. The dominant eastward-flying flocks were likely composed of shorebirds on their way from breeding areas in central or eastern Siberia to intermediate stopovers and final destinations in North and South America. The courses were more southerly into the Bering Strait, possibly because of topographical influence. At two areas, the Chukchi Sea and Koluchinskaya Bay, there was also a westward component of migrants. At the Chukchi Sea these were almost certainly passerine birds migrating from Alaska to wintering areas in Asia and Africa, while at Koluchinskaya Bay, king ciders on molt migration could represent an important part of the westward component. The overall mean altitude of flights was 1157 m, and flight altitude was positively correlated with latitude. The mean ground speed was 15.9 m/s and the mean airspeed was 14.1 m/s, indicating that on average the birds were experiencing a small tail wind component. The airspeed was a function of the tail wind component and the vertical speed; altitude and the side wind component did not contribute significantly to variation in airspeed in this data set. Comparing these results with similar data obtained from Siberia and Canada, we concluded that Beringia is a migration hotspot where intense bird migration crosses between Asia and Alaska in both directions.
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| 9. |
- Henningsson, Axel, et al.
(författare)
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Inferring the probability distribution over strain tensors in polycrystals from diffraction based measurements
- 2023
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Ingår i: Computer Methods in Applied Mechanics and Engineering. - : Elsevier. - 0045-7825 .- 1879-2138. ; 417:Part A
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Tidskriftsartikel (refereegranskat)abstract
- Polycrystals illuminated by high-energy X-rays or neutrons produce diffraction patterns in which the measured diffraction peaks encode the individual single crystal strain states. While state of the art X-ray and neutron diffraction approaches can be used to routinely recover per grain mean strain tensors, less work has been produced on the recovery of higher order statistics of the strain distributions across the individual grains. In the setting of small deformations, we consider the problem of estimating the crystal elastic strain tensor probability distribution from diffraction data. For the special case of multivariate Gaussian strain tensor probability distributions, we show that while the mean of the distribution is well defined from measurements, the covariance of strain has a null-space. We show that there exist exactly 6 orthogonal perturbations to this covariance matrix under which the measured strain signal is invariant. In particular, we provide analytical parametrisations of these perturbations together with the set of possible maximum-likelihood estimates for a multivariate Gaussian fit to data. The parametric description of the null-space provides insights into the strain PDF modes that cannot be accurately estimated from the diffraction data. Understanding these modes prevents erroneous conclusions from being drawn based on the data. Beyond Gaussian strain tensor probability densities, we derive an iterative radial basis regression scheme in which the strain tensor probability density is estimated by a sparse finite basis expansion. This is made possible by showing that the operator mapping the strain tensor probability density onto the measured histograms of directional strain is linear, without approximation. The utility of the proposed algorithm is demonstrated by numerical simulations in the setting of single crystal monochromatic X-ray scattering. The proposed regression methods were found to robustly reject outliers and accurately predict the strain tensor probability distributions in the presence of Gaussian measurement noise.
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| 10. |
- Henningsson, Asa M, et al.
(författare)
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Combinations of indigestible carbohydrates affect short-chain fatty acid formation in the hindgut of rats
- 2002
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Ingår i: Journal of Nutrition. - : Elsevier BV. - 0022-3166. ; 132:10, s. 104-3098
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Tidskriftsartikel (refereegranskat)abstract
- The fermentability and pattern of short-chain fatty acids (SCFA) formed in the hindgut of rats given various combinations of dietary fibers (DF) and resistant starch (RS) were investigated. Highly fermentable indigestible carbohydrates, i.e., guar gum (GG), pectin (Pec) and high amylose cornstarch (HAS), and a DF with a relatively high resistance to fermentation, i.e., wheat bran (WB), were included. The substrates were studied individually or as mixtures (GG + Pec, GG + WB and HAS + WB, 1:1, wt/wt indigestible carbohydrate basis) at a total concentration of 100 g indigestible carbohydrates/kg diet and fed to rats for 13 d. Rats fed Pec had a high proportion of acetic acid in the cecum (76 +/- 2% of total SCFA), whereas those fed GG had the highest proportion of propionic acid (31 +/- 4%, P <0.0005). Rats fed GG and Pec had low proportions of butyric acid (6 +/- 1 and 10 +/- 1%, respectively), whereas those fed both had a higher proportion of butyric acid (15 +/- 3%, P < 0.05). Consequently, the cecal butyric acid pool was twice as high in rats fed the GG + Pec mixture (44 +/- 9 micro mol) as in those fed the individual components (19 +/- 2 and 21 +/- 3 micro mol, respectively, P < 0.05). Rats fed HAS with WB had a greater fecal excretion of SCFA (184 +/- 19 micro mol/d) than those fed the individual components (77 +/- 10 and 116 +/- 12 micro mol/d in rats fed HAS and WB, respectively P < 0.05), suggesting that incorporation of WB delayed the site of fermentation of HAS to the distal part of the hindgut. In conclusion, the combination of indigestible carbohydrates may affect both SCFA patterns and the site of SCFA release in the rat hindgut.
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