| 1. |
- Andersson, Linda, 1973, et al.
(författare)
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Glucosylceramide synthase deficiency in the heart compromises β1-adrenergic receptor trafficking
- 2021
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Ingår i: European Heart Journal. - : Oxford University Press. - 0195-668X .- 1522-9645. ; 42:43, s. 4481-4492
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: Cardiac injury and remodelling are associated with the rearrangement of cardiac lipids. Glycosphingolipids are membrane lipids that are important for cellular structure and function, and cardiac dysfunction is a characteristic of rare monogenic diseases with defects in glycosphingolipid synthesis and turnover. However, it is not known how cardiac glycosphingolipids regulate cellular processes in the heart. The aim of this study is to determine the role of cardiac glycosphingolipids in heart function.METHODS AND RESULTS: Using human myocardial biopsies, we showed that the glycosphingolipids glucosylceramide and lactosylceramide are present at very low levels in non-ischaemic human heart with normal function and are elevated during remodelling. Similar results were observed in mouse models of cardiac remodelling. We also generated mice with cardiomyocyte-specific deficiency in Ugcg, the gene encoding glucosylceramide synthase (hUgcg-/- mice). In 9- to 10-week-old hUgcg-/- mice, contractile capacity in response to dobutamine stress was reduced. Older hUgcg-/- mice developed severe heart failure and left ventricular dilatation even under baseline conditions and died prematurely. Using RNA-seq and cell culture models, we showed defective endolysosomal retrograde trafficking and autophagy in Ugcg-deficient cardiomyocytes. We also showed that responsiveness to β-adrenergic stimulation was reduced in cardiomyocytes from hUgcg-/- mice and that Ugcg knockdown suppressed the internalization and trafficking of β1-adrenergic receptors.CONCLUSIONS: Our findings suggest that cardiac glycosphingolipids are required to maintain β-adrenergic signalling and contractile capacity in cardiomyocytes and to preserve normal heart function.
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| 2. |
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| 3. |
- Ekstrand, Elisabeth, et al.
(författare)
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Longitudinal changes of self-perceived manual ability the first year after stroke : A cohort study
- 2020
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Ingår i: BMC Neurology. - : Springer Science and Business Media LLC. - 1471-2377. ; 20:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Recovery patterns of motor function and activity capacity of the upper extremity after stroke have been described, but less is known about longitudinal changes of perceived manual activity performance. The aim of this study was to investigate longitudinal changes of self-perceived manual ability at several timepoints from onset until 12 months post-stroke in a cohort of consecutively recruited individuals with mild, moderate and severe stroke. Methods: The study included 106 participants from a non-selected cohort with first-ever mild, moderate or severe stroke and impaired upper extremity function (Stroke Arm Longitudinal Study at the University of Gothenburg, SALGOT). Self-perceived manual ability was assessed with the ABILHAND Questionnaire at 3 and 10 days, 4 weeks, 3, 6 and 12 months after stroke. Longitudinal change was assessed by linear mixed models (fixed and random effects) and adjusted models were built by adding effects of cofactors age, gender, stroke severity, living condition and affected hand. Results: Self-perceived manual ability increased over time the first year after stroke for the total group and the subgroups. The final adjusted model for the total group included fix-effects of time (expected mean change 0.24 logits per month) adjusted by age (-0.06 per year) and stroke severity (-0.19 per NIHSS-score). In addition to significant effect of time, the adjusted models for moderate stroke subgroup included fixed effect of age, and for mild and severe subgroups there was an interaction effect between time and age. Further analyses between time-points showed that no significant change of self-perceived manual ability was detected beyond 3 months post-stroke. Conclusions: Self-perceived manual ability increased over time the first year after stroke, and this change was to some degree modulated by age and stroke severity at onset. Most of the improvements occurred early, predominantly within the first three months after stroke.
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| 4. |
- Ekstrand, Elisabeth, et al.
(författare)
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Which clinical and sociodemographic determinants are associated with self-perceived manual ability at one year after stroke?
- 2020
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Ingår i: Disability and Rehabilitation. - : Informa UK Limited. - 0963-8288 .- 1464-5165. ; 42:16, s. 2279-2286
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To evaluate the impact of multiple potential sociodemographic and clinical stroke-related determinants on self-perceived manual ability in an unselected sample of individuals 12 months after first-ever stroke. Methods: A cross-sectional sample of 68 participants (mean age 66) with UE impairments were followed up at 12 months post stroke. Stroke severity at onset was moderate for the majority. Manual ability was assessed by the patient-reported outcome measure ABILHAND Questionnaire. Determinants included in the multivariate regression analysis were age, gender, living situation, vocational situation, affected hand, stroke severity at onset and UE disability (motor function, sensory function, joint motion, pain, grip strength, spasticity and activity capacity) at 12 months post stroke. Results: The strongest associated determinants with self-perceived manual ability were UE motor function and UE activity capacity at 12 months post-stroke. UE motor function together with age and grip strength explained 65% of the variance in one final multivariate model. UE activity capacity and grip strength explained 62% of the variance in a second final model. Conclusion: In order to understand self-perceived difficulties in manual ability in daily activities in persons with stroke, assessments of UE motor function and activity capacity are recommended. Implications for rehabilitation The ultimate goal of the upper extremity rehabilitation after stroke is to regain ability to use the UE in daily activities that are important to the individual in his or her own environment. This requires a good understanding of factors that are associated with self-perceived manual ability in order to tailor effective rehabilitation interventions. Upper extremity motor function and activity capacity are the strongest determinants associated with self-perceived manual ability one year after stroke. These factors are recommended to be included in the assessment battery in stroke to fully understand the disability in daily life.
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| 5. |
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| 6. |
- Ekstrand, Åsa, et al.
(författare)
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A Solution Synthetic Route to Nanophase Cobalt Film and Sponge
- 2005
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Ingår i: Chem. Mater. - : American Chemical Society (ACS). ; 17, s. 199-205
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Tidskriftsartikel (refereegranskat)abstract
- An efficient, low-cost solution-chemical route to nanophase cobalt as dense films and sponges has been developed. Co(NO3)2·6H2O and Co(OAc)2·4H2O were mixed with triethanolamine in methanol, and the solution was evaporated in air to a viscous liquid. Heating at 10 C min-1 to 470 and 500 C yielded highly porous sponges consisting of 3-6 and 9-11 nm sized face centered cubic (fcc) cobalt crystallites, respectively. Spin-coating on alumina and aluminum substrates with a 1 M Co-precursor solution and subsequent heating at 10 C min-1 to 500 C yielded dense films of <20 nm sized fcc cobalt crystallites. The microstructural and compositional evolution process on heating to form the cobalt metal was studied by TGA, DTA, and FT-IR spectroscopy, powder X-ray diffraction, TEM-EDS, and SEM-EDS. The C, N, and O contents could be kept low, 0.5, 0.02, and 0.2 wt %, respectively, at 700 C, but the carbon content could also reproducibly be adjusted to up to 13 wt % C in excess, by varying the precursor composition.
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| 7. |
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| 8. |
- Ekstrand, Åsa, et al.
(författare)
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Homogeneous WC–Co-Cemented Carbides from a Cobalt-Coated WC Powder Produced by a Novel Solution-Chemical Route
- 2007
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Ingår i: Journal of The American Ceramic Society. - : Wiley. - 0002-7820 .- 1551-2916. ; 90:11, s. 3449-3454
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Tidskriftsartikel (refereegranskat)abstract
- A solution chemical route to cobalt-coated WC-powder is described that allows for the preparation of WC–Co powders and compacts having a carbon content very close to the desired carbon content even under an inert atmosphere. The microstructural homogeneity in the sintered WC–Co composites when using the Co-coated grains was found to be superior as compared with conventionally mill-mixed powders, and the structural changes in the individual WC-grains were found to be much smaller, which is ascribed mainly to the fact that the coated grains do not require a grinding step leading to the formation of a tail of smaller WC grain sizes.
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| 9. |
- Ekstrand, Åsa, 1966-
(författare)
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Novel powder-coating solutions to improved micro-structures of ZnO based varistors, WC-Co cutting tools, and Co/Ni nano-phase films and sponges
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Solution chemistry is a versatile and powerful tool in the synthesis of designed, complex nano-level high-tech materials. Normally, the technique is considered too expensive for large-scale production of complex multi-component ceramic materials. This thesis describes the expansion of the useful area of solution processing to multi-component bulk materials such as ZnO-based high-field varistors and WC–Co cutting tools, by developing novel techniques for solution-based coating of conventionally prepared metal and ceramic powders. The chemistry and microstructure development in the preparation of coatings, and the sintering of the coated powders to compacts, were studied in detail by SEM-EDS, TEM-EDS, XRD, IR-spectroscopy, dilatometry, TGA and DSC chemical analysis.ZnO powder with a ca 20 nm thick, homogeneous oxide coat of Bi–Sb–Ni–Co–Mn–Cr–Al oxide was prepared. After sintering to dense varistor bodies, much improved microstructures with much reduced ZnO-grain sizes were obtained. This shows that the oxides added as liquid sintering aid and grain-growth inhibitor become much more active when added homogeneously as a skin on the ZnO powder.After sintering of cobalt-coated WC, much improved micro-structures were obtained with a much more narrow WC grain-size distribution than that obtained from starting powders mixed by a conventional milling route. Coated powders also obviate the need for the extensive milling of WC and Co powders used in conventional mixing.The novel solution route was also applied to preparation of porous sponges and thin films on metal, glass and Al2O3 of sub 20 nm sized Co- or Ni-particles.
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| 10. |
- Ekstrand, Åsa, et al.
(författare)
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Processing of ZnO-based varistors using oxide, alkoxide, nitrato-alkoxide and carboxylato precursors
- 1997
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Ingår i: Journal of Sol-Gel Science and Technology. - 0928-0707 .- 1573-4846. ; 8:1-3, s. 697-701
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated the preparation of ZnO varistors by different chemical solution routes with the aim of improving the homogeneity of the phases formed and to obtain a better control of microstructure. One conventional oxide mixing route and four solution chemical routes have been used to prepare the precursor materials. In all cases, the same composition (mol%) was used; ZnO (95.9), Bi2O3 (1), Sb2O3 (1), NiO (1), Co2O3 (0.5), MnO (0.5), Cr2O3 (0.1). The same sintering procedure was also applied. It was found that the precursor materials consisting of ZnO grains covered by a thin film of the additive oxides yielded smaller ZnO grains. Also the microstructure in the final compacts was improved, compared with that of compacts prepared from oxide mixing routes. The smaller ZnO grain size in the final compacts was attributed to the presence of spinel grains. The spinel grains are formed at lower temperatures and, when they reach a size of 1 μm, they hinder the growth of ZnO grains.
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| 11. |
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| 12. |
- Ekstrand, Åsa, et al.
(författare)
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Solution Synthesis of Nano-Phase Nickel as Film and Porous Electrode
- 2000
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Ingår i: Journal of Sol-Gel Science and Technology. - 0928-0707 .- 1573-4846. ; 19:1-3, s. 353-356
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Tidskriftsartikel (refereegranskat)abstract
- Routes to nano-phase nickel in the forms of highly porous sponges and dense films have been developed.Nickel acetate and nitrate were mixed with triethanolamine and methanol, and evaporated to a concentrated liquid.Heat-treatment at 10±C/min to 170±C under N2 atmosphere yielded a highly porous sponge consisting of <10 nmsized Ni crystallites. Deposition of a 1 M nickel precursor solution on polycrystalline Al2O3, SnO2 : F coated glassor titanium substrates spinning at 2700 rpm, followed by heat-treatment at 10±C/min to 400±C yielded smooth anddense nickel films consisting of 3–5 nm sized crystallites. The precursor concentrate was studied by FT-IR andthe phase development on heat-treatment was studied by thermogravimetric analysis, powder X-ray diffraction,scanning and transmission electron microscopy.
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| 13. |
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| 14. |
- Karlsson, Anne-Li, et al.
(författare)
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Bet v 1 homologues in strawberry identified as IgE-binding proteins and presumptive allergens
- 2004
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Ingår i: Allergy. - : Wiley. - 1398-9995 .- 0105-4538. ; 59:12, s. 1277-1284
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Tidskriftsartikel (refereegranskat)abstract
- Background: No strawberry allergen has so far been identified and characterized. Methods: Serum samples were collected from patients with a suggestive case history of adverse reactions to strawberry and other fruits. Extracts from fresh and frozen strawberries were analysed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), Western blotting and mass spectrometry. Patient blood samples were analysed for inhibition of IgE binding and basophil degranulation. Results: Several IgE-binding proteins could be detected. In more than half of the patient sera, a 20/18-kDa doublet band was observed in Western blotting. These two bands were excised and analysed by mass spectrometry showing the presence of proteins belonging to the Bet v 1 family of allergens. Inhibition of the IgE binding to the 20/18-kDa doublet was obtained by addition of two recombinantly expressed allergens belonging to the Bet v 1 family (Bet v 1 and Mal d 1) and strawberry protein extract. In a cell-based assay of patient blood samples, basophil degranulation could be induced by strawberry protein extract and by Bet v 1 and Mal d 1. Conclusions: We conclude that strawberry homologues to Bet v 1 may be allergens of importance for adverse reactions to strawberry.
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| 15. |
- Kritikos, Mikael, et al.
(författare)
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Synthesis, Structure and Properties of Na2Zn(OEt)4(HOEt)5
- 2004
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Ingår i: Journal of Sol-Gel Science and Technology. ; 32, s. 19-23
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Tidskriftsartikel (refereegranskat)abstract
- The synthesis, structure and properties of Na2Zn(OEt)4(HOEt)5, having the right Na:Zn ratio for sol-gel synthesis of the highly Na-ion conducting ceramic Nai1.8Zn0.9Si1.1O4, is described. It was synthesised in high yield by a metathesis reaction of ZnCl2 and 4NaOEt in ethanol or ethanol/toluene solvent. The structure was determined by single-crystal X-ray methods and consists of two symmetry related polymeric strands with the metal sequence ...-Zn-Na-Na-Zn-.... Extensive hydrogen bonding is present within each chain. Further characterization was lmade with IR- and Raman-spectroscopy and thermo-calorimetry, showing that the compound is stable to 65°C.
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| 16. |
- Olsson, Viktoria, et al.
(författare)
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Forskare tar temp på tinat kött
- 2023
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Ingår i: Kött & Chark. - 0047-3510. ; :6, s. 20-22
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 19. |
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| 20. |
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| 21. |
- Westin, Gunnar, et al.
(författare)
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Preparation of ZnO-based varistors by the sol-gel technique
- 1994
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Ingår i: Journal of Materials Chemistry. - 0959-9428 .- 1364-5501. ; 4:4, s. 615-621
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Tidskriftsartikel (refereegranskat)abstract
- ZnO-based varistors consisting of 96 mol% ZnO and 4 mol% additive oxides (Bi2O3, Sb2O3, NiO, Co2O3, MnO and Cr2O3) have been prepared. Four different procedures have been applied to obtain the starting powder mixture. Three of the procedures involve sol–gel processing of the additive oxide mixture, and in two cases the surface of the ZnO grains has been covered by the additive oxides. The microstructural and phase composition development during the sintering process has been monitored and the electrical properties of the varistors have been determined. Higher breakdown voltages are obtained for varistors produced by sol–gel-processed starting materials, and the highest values are found for varistors prepared from ZnO grains covered with the additive oxides. Phase analysis revealed that the spinel phase, which retards the grain growth of the ZnO particles, is formed at lower temperatures and in larger amounts in these compacts. The higher breakdown voltages of these compacts thus seem to be related to the content of more finely grained ZnO particles in these compacts.
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| 23. |
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