| 1. |
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| 2. |
- Björkman, Anne, 1981, et al.
(författare)
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Plant functional trait change across a warming tundra biome
- 2018
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 562:7725, s. 57-62
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Tidskriftsartikel (refereegranskat)abstract
- The tundra is warming more rapidly than any other biome on Earth, and the potential ramifications are far-reaching because of global feedback effects between vegetation and climate. A better understanding of how environmental factors shape plant structure and function is crucial for predicting the consequences of environmental change for ecosystem functioning. Here we explore the biome-wide relationships between temperature, moisture and seven key plant functional traits both across space and over three decades of warming at 117 tundra locations. Spatial temperature–trait relationships were generally strong but soil moisture had a marked influence on the strength and direction of these relationships, highlighting the potentially important influence of changes in water availability on future trait shifts in tundra plant communities. Community height increased with warming across all sites over the past three decades, but other traits lagged far behind predicted rates of change. Our findings highlight the challenge of using space-for-time substitution to predict the functional consequences of future warming and suggest that functions that are tied closely to plant height will experience the most rapid change. They also reveal the strength with which environmental factors shape biotic communities at the coldest extremes of the planet and will help to improve projections of functional changes in tundra ecosystems with climate warming.
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| 3. |
- Kenny, Gavin G., et al.
(författare)
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A Late Paleocene age for Greenland’s Hiawatha impact structure
- 2022
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Ingår i: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 8:10
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Tidskriftsartikel (refereegranskat)abstract
- The ~31-km-wide Hiawatha structure, located beneath Hiawatha Glacier in northwestern Greenland, has been proposed as an impact structure that may have formed after the Pleistocene inception of the Greenland Ice Sheet. To date the structure, we conducted 40Ar/39Ar analyses on glaciofluvial sand and U-Pb analyses on zircon separated from glaciofluvial pebbles of impact melt rock, all sampled immediately downstream of Hiawatha Glacier. Unshocked zircon in the impact melt rocks dates to ~1915 million years (Ma), consistent with felsic intrusions found in local bedrock. The 40Ar/39Ar data indicate Late Paleocene resetting and shocked zircon dates to 57.99 ± 0.54 Ma, which we interpret as the impact age. Consequently, the Hiawatha impact structure far predates Pleistocene glaciation and is unrelated to either the Paleocene-Eocene Thermal Maximum or flood basalt volcanism in east Greenland. However, it was contemporaneous with the Paleocene Carbon Isotope Maximum, although the impact’s exact paleoenvironmental and climatic significance awaits further investigation.
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| 4. |
- Elmendorf, Sarah C., et al.
(författare)
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Global assessment of experimental climate warming on tundra vegetation : heterogeneity over space and time
- 2012
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Ingår i: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 15:2, s. 164-175
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Forskningsöversikt (refereegranskat)abstract
- Understanding the sensitivity of tundra vegetation to climate warming is critical to forecasting future biodiversity and vegetation feedbacks to climate. In situ warming experiments accelerate climate change on a small scale to forecast responses of local plant communities. Limitations of this approach include the apparent site-specificity of results and uncertainty about the power of short-term studies to anticipate longer term change. We address these issues with a synthesis of 61 experimental warming studies, of up to 20 years duration, in tundra sites worldwide. The response of plant groups to warming often differed with ambient summer temperature, soil moisture and experimental duration. Shrubs increased with warming only where ambient temperature was high, whereas graminoids increased primarily in the coldest study sites. Linear increases in effect size over time were frequently observed. There was little indication of saturating or accelerating effects, as would be predicted if negative or positive vegetation feedbacks were common. These results indicate that tundra vegetation exhibits strong regional variation in response to warming, and that in vulnerable regions, cumulative effects of long-term warming on tundra vegetation and associated ecosystem consequences have the potential to be much greater than we have observed to date.
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| 5. |
- Elmendorf, Sarah C., et al.
(författare)
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Plot-scale evidence of tundra vegetation change and links to recent summer warming
- 2012
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Ingår i: Nature Climate Change. - : Nature Publishing Group. - 1758-678X .- 1758-6798. ; 2:6, s. 453-457
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Tidskriftsartikel (refereegranskat)abstract
- Temperature is increasing at unprecedented rates across most of the tundra biome. Remote-sensing data indicate that contemporary climate warming has already resulted in increased productivity over much of the Arctic, but plot-based evidence for vegetation transformation is not widespread. We analysed change in tundra vegetation surveyed between 1980 and 2010 in 158 plant communities spread across 46 locations.We found biome-wide trends of increased height of the plant canopy and maximum observed plant height for most vascular growth forms; increased abundance of litter; increased abundance of evergreen, low-growing and tall shrubs; and decreased abundance of bare ground. Intersite comparisons indicated an association between the degree of summer warming and change in vascular plant abundance, with shrubs, forbs and rushes increasing with warming. However, the association was dependent on the climate zone, the moisture regime and the presence of permafrost. Our data provide plot-scale evidence linking changes in vascular plant abundance to local summer warming in widely dispersed tundra locations across the globe.
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| 6. |
- Björkman, Anne, 1981, et al.
(författare)
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Tundra Trait Team: A database of plant traits spanning the tundra biome
- 2018
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Ingår i: Global Ecology and Biogeography. - : Wiley. - 1466-822X .- 1466-8238. ; 27:12, s. 1402-1411
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Tidskriftsartikel (refereegranskat)abstract
- © 2018 The Authors Global Ecology and Biogeography Published by John Wiley & Sons Ltd Motivation: The Tundra Trait Team (TTT) database includes field-based measurements of key traits related to plant form and function at multiple sites across the tundra biome. This dataset can be used to address theoretical questions about plant strategy and trade-offs, trait–environment relationships and environmental filtering, and trait variation across spatial scales, to validate satellite data, and to inform Earth system model parameters. Main types of variable contained: The database contains 91,970 measurements of 18 plant traits. The most frequently measured traits (>1,000 observations each) include plant height, leaf area, specific leaf area, leaf fresh and dry mass, leaf dry matter content, leaf nitrogen, carbon and phosphorus content, leaf C:N and N:P, seed mass, and stem specific density. Spatial location and grain: Measurements were collected in tundra habitats in both the Northern and Southern Hemispheres, including Arctic sites in Alaska, Canada, Greenland, Fennoscandia and Siberia, alpine sites in the European Alps, Colorado Rockies, Caucasus, Ural Mountains, Pyrenees, Australian Alps, and Central Otago Mountains (New Zealand), and sub-Antarctic Marion Island. More than 99% of observations are georeferenced. Time period and grain: All data were collected between 1964 and 2018. A small number of sites have repeated trait measurements at two or more time periods. Major taxa and level of measurement: Trait measurements were made on 978 terrestrial vascular plant species growing in tundra habitats. Most observations are on individuals (86%), while the remainder represent plot or site means or maximums per species. Software format: csv file and GitHub repository with data cleaning scripts in R; contribution to TRY plant trait database (www.try-db.org) to be included in the next version release.
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| 7. |
- Garrard, S. L., et al.
(författare)
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Biological impacts of ocean acidification: a postgraduate perspective on research priorities
- 2013
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Ingår i: Marine Biology. - : Springer Science and Business Media LLC. - 0025-3162 .- 1432-1793. ; 160:8, s. 1789-1805
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Tidskriftsartikel (refereegranskat)abstract
- Research into the effects of ocean acidification (OA) on marine organisms has greatly increased during the past decade, as realization of the potential dramatic impacts has grown. Studies have revealed the multifarious responses of organisms to OA conditions, indicating a high level of intra- and interspecific variation in species' ability to accommodate these alterations. If we are to provide policy makers with sound, scientific input regarding the expected consequences of OA, we need a broader understanding of these predicted changes. As a group of 20 multi-disciplinary postgraduate students from around the globe, with a study focus on OA, we are a strong representation of 'next generation' scientists in this field. In this unique cumulative paper, we review knowledge gaps in terms of assessing the biological impacts of OA, outlining directions for future research.
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| 8. |
- Kjær, Kurt H., et al.
(författare)
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Glacier response to the Little Ice Age during the Neoglacial cooling in Greenland
- 2022
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Ingår i: Earth-Science Reviews. - : Elsevier. - 0012-8252 .- 1872-6828. ; 227
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Tidskriftsartikel (refereegranskat)abstract
- In the Northern Hemisphere, an insolation driven Early to Middle Holocene Thermal Maximum was followed by a Neoglacial cooling that culminated during the Little Ice Age (LIA). Here, we review the glacier response to this Neoglacial cooling in Greenland. Changes in the ice margins of outlet glaciers from the Greenland Ice Sheet as well as local glaciers and ice caps are synthesized Greenland-wide. In addition, we compare temperature reconstructions from ice cores, elevation changes of the ice sheet across Greenland and oceanographic reconstructions from marine sediment cores over the past 5,000 years. The data are derived from a comprehensive review of the literature supplemented with unpublished reports. Our review provides a synthesis of the sensitivity of the Greenland ice margins and their variability, which is critical to understanding how Neoglacial glacier activity was interrupted by the current anthropogenic warming. We have reconstructed three distinct periods of glacier expansion from our compilation: two older Neoglacial advances at 2,500 – 1,700 yrs. BP (Before Present = 1950 CE, Common Era) and 1,250 – 950 yrs. BP; followed by a general advance during the younger Neoglacial between 700-50 yrs. BP, which represents the LIA. There is still insufficient data to outline the detailed spatio-temporal relationships between these periods of glacier expansion. Many glaciers advanced early in the Neoglacial and persisted in close proximity to their present-day position until the end of the LIA. Thus, the LIA response to Northern Hemisphere cooling must be seen within the wider context of the entire Neoglacial period of the past 5,000 years. Ice expansion appears to be closely linked to changes in ice sheet elevation, accumulation, and temperature as well as surface-water cooling in the surrounding oceans. At least for the two youngest Neoglacial advances, volcanic forcing triggering a sea-ice /ocean feedback, could explain their initiation. There are probably several LIA glacier fluctuations since the first culmination close to 1250 CE (Common Era) and available data suggests ice culminations in the 1400s, early to mid-1700s and early to mid-1800s CE. The last LIA maxima lasted until the present deglaciation commenced around 50 yrs. BP (1900 CE). The constraints provided here on the timing and magnitude of LIA glacier fluctuations delivers a more realistic background validation for modelling future ice sheet stability.
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| 9. |
- Metcalfe, Daniel B., et al.
(författare)
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Patchy field sampling biases understanding of climate change impacts across the Arctic
- 2018
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Ingår i: Nature Ecology and Evolution. - : Springer Science and Business Media LLC. - 2397-334X. ; 2:9, s. 1443-1448
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Tidskriftsartikel (refereegranskat)abstract
- Effective societal responses to rapid climate change in the Arctic rely on an accurate representation of region-specific ecosystem properties and processes. However, this is limited by the scarcity and patchy distribution of field measurements. Here, we use a comprehensive, geo-referenced database of primary field measurements in 1,840 published studies across the Arctic to identify statistically significant spatial biases in field sampling and study citation across this globally important region. We find that 31% of all study citations are derived from sites located within 50 km of just two research sites: Toolik Lake in the USA and Abisko in Sweden. Furthermore, relatively colder, more rapidly warming and sparsely vegetated sites are under-sampled and under-recognized in terms of citations, particularly among microbiology-related studies. The poorly sampled and cited areas, mainly in the Canadian high-Arctic archipelago and the Arctic coastline of Russia, constitute a large fraction of the Arctic ice-free land area. Our results suggest that the current pattern of sampling and citation may bias the scientific consensuses that underpin attempts to accurately predict and effectively mitigate climate change in the region. Further work is required to increase both the quality and quantity of sampling, and incorporate existing literature from poorly cited areas to generate a more representative picture of Arctic climate change and its environmental impacts.
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| 10. |
- Wang, Yucheng, et al.
(författare)
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Late Quaternary Dynamics of Arctic Biota from Ancient Environmental Genomics
- 2021
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 600:7887, s. 86-92
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Tidskriftsartikel (refereegranskat)abstract
- During the last glacial–interglacial cycle, Arctic biotas experienced substantial climatic changes, yet the nature, extent and rate of their responses are not fully understood1–8. Here we report a large-scale environmental DNA metagenomic study of ancient plant and mammal communities, analysing 535 permafrost and lake sediment samples from across the Arctic spanning the past 50,000 years. Furthermore, we present 1,541 contemporary plant genome assemblies that were generated as reference sequences. Our study provides several insights into the long-term dynamics of the Arctic biota at the circumpolar and regional scales. Our key fndings include: (1) a relatively homogeneous steppe–tundra fora dominated the Arctic during the Last Glacial Maximum, followed by regional divergence of vegetation during the Holocene epoch; (2) certain grazing animals consistently co-occurred in space and time; (3) humans appear to have been a minor factor in driving animal distributions; (4) higher efective precipitation, as well as an increase in the proportion of wetland plants, show negative efects on animal diversity; (5) the persistence of the steppe–tundra vegetation in northern Siberia enabled the late survival of several now-extinct megafauna species, including the woolly mammoth until 3.9 ± 0.2 thousand years ago (ka) and the woolly rhinoceros until 9.8 ± 0.2 ka; and (6) phylogenetic analysis of mammoth environmental DNA reveals a previously unsampled mitochondrial lineage. Our fndings highlight the power of ancient environmental metagenomics analyses to advance understanding of population histories and long-term ecological dynamics
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| 11. |
- Wang, Yucheng, et al.
(författare)
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Reply to: When did mammoths go extinct?
- 2022
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 612:7938, s. 4-6
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Tidskriftsartikel (refereegranskat)
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| 12. |
- Abrahamsson, Per-Anders, et al.
(författare)
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Radioimmunoassay of beta-microseminoprotein, a prostatic-secreted protein present in sera of both men and women
- 1989
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Ingår i: Clinical Chemistry. - 0009-9147. ; 35:7, s. 1497-1503
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Tidskriftsartikel (refereegranskat)abstract
- We describe a simple radioimmunoassay of beta-microseminoprotein, one of the three most abundant secretory proteins of the prostate gland. The detection limit of the assay is 1 microgram/L, and its precision, expressed as the total coefficient of variation, is less than 10% for values between 10 and 150 micrograms/L. Using this assay, we found that beta-microseminoprotein immunoreactivity was present in sera from both sexes at about the same concentration. The protein detected had the same molecular size on gel chromatography as the protein isolated from seminal plasma, and dilution curves for the sera paralleled that for the pure protein. The findings suggest that beta-microseminoprotein is present in serum of healthy subjects of both sexes and that it originates in tissue other than the prostate gland. The range of the serum concentration was 0-10.6 micrograms/L (median 4.1) for 51 healthy adult women and 1.1-14.7 micrograms/L (median 6.2) for 35 healthy adult men not older than 40 years. In males with prostatic cancer the concentration in serum was highly variable and often greatly increased. The concentration of beta-microseminoprotein was correlated with that of creatinine in serum, suggesting that the protein is eliminated--at least partly--from the circulation by glomerular filtration. Little of the protein was present in the urine of women. In urine from men the concentration was high and variable, probably because of local contribution from the prostate gland to the urethral urine.
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| 13. |
- Aevarsson, Arnthór, et al.
(författare)
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Going to extremes - a metagenomic journey into the dark matter of life
- 2021
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Ingår i: FEMS Microbiology Letters. - : Oxford University Press (OUP). - 1574-6968. ; 368:12
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Forskningsöversikt (refereegranskat)abstract
- The Virus-X-Viral Metagenomics for Innovation Value-project was a scientific expedition to explore and exploit uncharted territory of genetic diversity in extreme natural environments such as geothermal hot springs and deep-sea ocean ecosystems. Specifically, the project was set to analyse and exploit viral metagenomes with the ultimate goal of developing new gene products with high innovation value for applications in biotechnology, pharmaceutical, medical, and the life science sectors. Viral gene pool analysis is also essential to obtain fundamental insight into ecosystem dynamics and to investigate how viruses influence the evolution of microbes and multicellular organisms. The Virus-X Consortium, established in 2016, included experts from eight European countries. The unique approach based on high throughput bioinformatics technologies combined with structural and functional studies resulted in the development of a biodiscovery pipeline of significant capacity and scale. The activities within the Virus-X consortium cover the entire range from bioprospecting and methods development in bioinformatics to protein production and characterisation, with the final goal of translating our results into new products for the bioeconomy. The significant impact the consortium made in all of these areas was possible due to the successful cooperation between expert teams that worked together to solve a complex scientific problem using state-of-the-art technologies as well as developing novel tools to explore the virosphere, widely considered as the last great frontier of life.
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| 14. |
- Andresen, Camilla S., et al.
(författare)
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Sediment discharge from Greenland's marine-terminating glaciers is linked with surface melt
- 2024
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Ingår i: Nature Communications. - 2041-1723. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- Sediment discharged from the Greenland Ice Sheet delivers nutrients to marine ecosystems around Greenland and shapes seafloor habitats. Current estimates of the total sediment flux are constrained by observations from land-terminating glaciers only. Addressing this gap, our study presents a budget derived from observations at 30 marine-margin locations. Analyzing sediment cores from nine glaciated fjords, we assess spatial deposition since 1950. A significant correlation is established between mass accumulation rates, normalized by surface runoff, and distance down-fjord. This enables calculating annual sediment flux at any fjord point based on nearby marine-terminating outlet glacier melt data. Findings reveal a total annual sediment flux of 1.324 + /- 0.79 Gt yr-1 over the period 2010-2020 from all marine-terminating glaciers to the fjords. These estimates are valuable for studies aiming to understand the basal ice sheet conditions and for studies predicting ecosystem changes in Greenland's fjords and offshore areas as the ice sheet melts and sediment discharge increase.
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| 15. |
- Björk, Anders, et al.
(författare)
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Making an ultralow platinum content bimetallic catalyst on carbon fibres for electro-oxidation of ammonia in wastewater
- 2019
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Ingår i: Sustainable Energy & Fuels. - 2398-4902.
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Tidskriftsartikel (refereegranskat)abstract
- Electrocatalysis of wastewater containing ammonia is a promising alternative to chemical and biological water purification for several reasons, one being that energy-rich hydrogen gas is generated as a by-product while the reaction can be strictly controlled to meet demands. An objective has been to reduce the loading of expensive platinum (Pt) in the catalyst electrodes, and to reduce the poisoning of the metal surface during the electrolysis. Herein, the co-deposition of a copper–platinum (Cu–Pt) bimetallic alloy onto carbon filaments, stripped from their polymeric coating, is shown to give an electrocatalytic performance superior to that of pure Pt at a content of less than 3 wt% Pt. The key to the enhanced performance was to take advantage of micrometer-sized carbon filaments to distribute a very large bimetallic alloy surface uniformly over the filaments. The Cu–Pt-alloy-coated filaments also suffer less electrode poisoning than pure Pt, and are bonded more strongly to the carbon fibre due to better mechanical interlocking between the bimetallic alloy and the carbon filaments. High-resolution electron microscopy studies combined with a tuned electro-deposition process made it possible to tailor the catalyst micro/nano morphology to reach a uniform coverage, surrounding the entire carbon filaments. The results are promising steps towards large-scale wastewater treatment, combined with clean energy production from regenerated hydrogen.
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| 16. |
- Byström, Anders S, et al.
(författare)
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Differentially expressed trmD ribosomal protein operon of Escherichia coli is transcribed as a single polycistronic mRNA species
- 1989
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Ingår i: Journal of Molecular Biology. - : Academic Press. - 0022-2836 .- 1089-8638. ; 208:4, s. 575-586
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Tidskriftsartikel (refereegranskat)abstract
- The trmD operon is a four-cistron operon in which the first and fourth genes encode ribosomal proteins S16 (rpsP) and L19 (rplS), respectively. The second gene encodes a 21,000 Mr polypeptide of unknown function and the third gene (trmD) encodes the enzyme tRNA(m1G37)methyltransferase, which catalyzes the formation of 1-methylguanosine (m1G) next to the 3' end of the anticodon (position 37) of some tRNAs in Escherichia coli. Here we show under all regulatory conditions studied, transcription initiates at one unique site, and the entire operon is transcribed into one polycistronic mRNA. Between the promoter and the first gene, rpsP, an attenuator-like structure is found (delta G = -18 kcal; 1 cal = 4.184 J), followed by four uridine residues. This structure is functional in vitro, and terminates more than two-thirds of the transcripts. The different parts of the trmD operon mRNA decay at a uniform rate. The stability of the trmD mRNA is not reduced with decreasing growth rate, which is in contrast to what has been found for other ribosomal protein mRNAs. Furthermore, earlier experiments have shown the existence of differential expression as well as non-co-ordinate regulation within the operon. Our results are consistent with the regulation of the trmD operon being due to some mechanism(s) operating at the post-transcriptional level, and do not involve differential degradation of different mRNA segments, internal promoters or internal terminators.
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| 17. |
- Eberhardson, Michael, et al.
(författare)
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Tumour necrosis factor inhibitors in Crohn's disease and the effect on surgery rates
- 2022
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Ingår i: Colorectal Disease. - : Wiley. - 1462-8910 .- 1463-1318. ; 24:4, s. 470-483
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Tidskriftsartikel (refereegranskat)abstract
- Aim: Surgery is an important therapeutic option for Crohn's disease. The need for first bowel surgery seems to have decreased with the introduction of tumour necrosis factor inhibitors (TNFi; adalimumab or infliximab). However, the impact of TNFi on the need for intestinal surgery in Crohn's disease patients irrespective of prior bowel resection is not known. The aim of this work is to compare the incidence of bowel surgery in Crohn's disease patients who remain on TNFi treatment versus those who discontinue it. Method: We performed a nationwide register-based observational cohort study in Sweden of all incident and prevalent cases of Crohn's disease who started first-line TNFi treatment between 2006 and 2017. Patients were categorized according to TNFi treatment retention less than or beyond 1 year. The study cohort was evaluated with regard to incidence of bowel surgery from 12 months after the first ever TNFi dispensation. Results: We identified 5003 Crohn's disease patients with TNFi exposure: 3748 surgery naïve and 1255 with bowel surgery prior to TNFi initiation. Of these patients, 7% (n = 353) were subjected to abdominal surgery during the first 12 months after the start of TNFi and were subsequently excluded from the main analysis. A majority (62%) continued TNFi for 12 months or more. Treatment with TNFi for less than 12 months was associated with a significantly higher surgery rate compared with patients who continued on TNFi for 12 months or more (hazard ratio 1.26, 95% CI 1.09–1.46; p = 0.002). Conclusion: Treatment with TNFi for less than 12 months was associated with a higher risk of bowel surgery in Crohn's disease patients compared with those who continued TNFi for 12 months or more.
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| 18. |
- Eneslätt, Kjell, et al.
(författare)
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Signatures of T cells as correlates of immunity to Francisella tularensis
- 2012
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:3, s. e32367-
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Tidskriftsartikel (refereegranskat)abstract
- Tularemia or vaccination with the live vaccine strain (LVS) of Francisella tularensis confers long-lived cell-mediated immunity. We hypothesized that this immunity depends on polyfunctional memory T cells, i.e., CD4(+) and/or CD8(+) T cells with the capability to simultaneously express several functional markers. Multiparametric flow cytometry, measurement of secreted cytokines, and analysis of lymphocyte proliferation were used to characterize in vitro recall responses of peripheral blood mononuclear cells (PBMC) to killed F. tularensis antigens from the LVS or Schu S4 strains. PBMC responses were compared between individuals who had contracted tularemia, had been vaccinated, or had not been exposed to F. tularensis (naive). Significant differences were detected between either of the immune donor groups and naive individuals for secreted levels of IL-5, IL-6, IL-10, IL-12, IL-13, IFN-gamma, MCP-1, and MIP-1 beta. Expression of IFN-gamma, MIP-1 beta, and CD107a by CD4(+)CD45RO(+) or CD8(+) CD45RO(+) T cells correlated to antigen concentrations. In particular, IFN-gamma and MIP-1 beta strongly discriminated between immune and naive individuals. Only one cytokine, IL-6, discriminated between the two groups of immune individuals. Notably, IL-2- or TNF-alpha-secretion was low. Our results identify functional signatures of T cells that may serve as correlates of immunity and protection against F. tularensis.
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| 19. |
- Hånell, Anders, et al.
(författare)
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Genetic Deletion and Pharmacological Inhibition of Nogo-66 Receptor Impairs Cognitive Outcome after Traumatic Brain Injury in Mice
- 2010
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Ingår i: Journal of Neurotrauma. - : Mary Ann Liebert Inc. - 0897-7151 .- 1557-9042. ; 27:7, s. 1297-1309
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Tidskriftsartikel (refereegranskat)abstract
- Functional recovery is markedly restricted following traumatic brain injury (TBI), partly due to myelin-associated inhibitors including Nogo-A, myelin-associated glycoprotein (MAG) and oligodendrocyte myelin glycoprotein (OMgp), that all bind to the Nogo-66 receptor-1 (NgR1). In previous studies, pharmacological neutralization of both Nogo-A and MAG improved outcome following TBI in the rat, and neutralization of NgR1 improved outcome following spinal cord injury and stroke in rodent models. However, the behavioral and histological effects of NgR1 inhibition have not previously been evaluated in TBI. We hypothesized that NgR1 negatively influences behavioral recovery following TBI, and evaluated NgR1(-/-) mice (NgR1(-/-) study) and, in a separate study, soluble NgR1 infused intracerebroventricularly immediately post-injury to neutralize NgR1 (sNgR1 study) following TBI in mice using a controlled cortical impact (CCI) injury model. In both studies, motor function, TBI-induced loss of tissue, and hippocampal beta-amyloid immunohistochemistry were not altered up to 5 weeks post-injury. Surprisingly, cognitive function (as evaluated with the Morris water maze at 4 weeks post-injury) was significantly impaired both in NgR1(-/-) mice and in mice treated with soluble NgR1. In the sNgR1 study, we evaluated hippocampal mossy fiber sprouting using the Timm stain and found it to be increased at 5 weeks following TBI. Neutralization of NgR1 significantly increased mossy fiber sprouting in sham-injured animals, but not in brain-injured animals. Our data suggest a complex role for myelin-associated inhibitors in the behavioral recovery process following TBI, and urge caution when inhibiting NgR1 in the early post-injury period.
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| 20. |
- Lin, Chung-Ying, et al.
(författare)
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Psychological distress and quality of life in Iranian adolescents with overweight/obesity : mediating roles of weight bias internalization and insomnia
- 2020
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Ingår i: Eating and Weight Disorders. - : Springer. - 1124-4909 .- 1590-1262. ; 25, s. 1583-1592
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To examine whether weight-related self-stigma (aka weight bias internalization) and insomnia are potential predictors of psychological distress and quality of life (QoL) among Iranian adolescents with overweight (OW)/obesity (OB). To examine whether weight-related self-stigma and insomnia are potential mediators in the relationship between excess weight and health outcomes of distress and QoL.METHODS: All participants (n = 934; 444 males; mean age = 15.7 ± 1.2 years; zBMI = 2.8 ± 1.0) completed questionnaires on weight-related self-stigma and insomnia at baseline. Six months later, they completed questionnaires on psychological distress and QoL to assess health outcomes. Relationships among variables were tested using mediation analyses with bootstrapping method.RESULTS: Weight-related self-stigma significantly mediated the effects of zBMI on psychological distress (effect = 0.22; bootstrapping SE = 0.09; 95% CI = 0.08, 0.45), psychosocial QoL (effect = - 0.64; bootstrapping SE = 0.19; 95% CI = - 1.10, - 0.32), and physical QoL (effect = - 1.35; bootstrapping SE = 0.54; 95% CI = - 2.43, - 0.26). Insomnia also significantly mediated the effects of zBMI on psychological distress (effect = 2.18; bootstrapping SE = 0.31; 95% CI = 1.61, 2.81), psychosocial QoL (effect = - 0.89; bootstrapping SE = 0.33; 95% CI = - 1.60, - 0.28), and physical QoL (effect = - 0.83; bootstrapping SE = 0.42; 95% CI = - 1.69, - 0.02). Full mediations were found in psychosocial QoL; partial mediations were found in psychological distress and physical QoL.CONCLUSIONS: Weight-related self-stigma and insomnia were significant mediators in the effects of excess weight on health outcomes. Therefore, it is important to identify and treat weight-related self-stigma and insomnia for adolescents with OW/OB.LEVEL OF EVIDENCE: Level V, cross-sectional descriptive study.
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| 21. |
- Martin, Myriam, et al.
(författare)
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Plasma C4d as marker for lupus nephritis in systemic lupus erythematosus
- 2017
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Ingår i: Arthritis Research and Therapy. - : Springer Science and Business Media LLC. - 1478-6354 .- 1478-6362. ; 19:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: In the present study, we sought to evaluate the complement activation product C4d as a marker for lupus nephritis in systemic lupus erythematosus (SLE). Methods: C4d levels were determined by enzyme-linked immunosorbent assay in plasma samples of patients with established SLE using a novel approach based on detection of a short linear cleavage neoepitope. Cross-sectional associations were studied in 98 patients with SLE with samples taken at lower or higher respective disease activity. Temporal associations were investigated in 69 patients with SLE who were followed longitudinally for up to 5 years. Plasma samples from 77 healthy donors were included as controls. Results: C4d levels were negligible in healthy control subjects and significantly increased in patients with SLE in the cross-sectional study (p < 0.0001). C4d levels discriminated between higher and lower disease activity according to ROC curve analysis (p < 0.001), exhibiting a positive predictive value of 68%. At higher disease activity, C4d levels correlated with the modified Systemic Lupus Erythematosus Disease Activity Index (p = 0.011) and predominantly with lupus nephritis (p = 0.003), exhibiting a sensitivity of 79% to identify patients with nephritis. High C4d levels together with the presence of anti-dsDNA autoantibodies preceded and thus predicted future lupus nephritis in the longitudinal study (OR 5.4, 95% CI 1.4-21.3). When we considered only patients with renal involvement (19 of 69) during the longitudinal study, we found that high C4d levels alone could forecast recurrence of future lupus nephritis (OR 3.3, 95% CI 1.2-9.6). Conclusions: C4d appears to be a valuable marker for use in monitoring of patients with SLE, particularly for lupus nephritis. Importantly, C4d levels can predict impending flares of lupus nephritis and may thus be useful for informing treatment.
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| 22. |
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| 23. |
- Mårtensson, Sophie, et al.
(författare)
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Bridging the Gap between Caring and Nursing Practice : Undergraduate Nursing Students Experiences of Learning Caring Behaviors with Standaradized Patients in Simulation
- 2023
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Konferensbidrag (refereegranskat)abstract
- Motivation & AimAlthough school of nursing curricula often refer to caring as the central core in nursing practice, students often have a gap in understanding and knowing how to intertwine caring in all aspect of nursing practice. Thus, nursing curricula often tend to focus more on developing psychomotor skills and knowledge, referred to as doing, with less concentration on how one interacts with patients. Even though there has been extensive research on simulation in nursing education there are limited studies focusing on the intentional and visible incorporation of compassionate and competent caring behavior in simulations. Therefore, the aim was to describe undergraduate nursing students’ experiences of practicing caring behaviors with a standardized patient. MethodA sample of forty-eight fourth semester undergraduate nursing students enrolled in a five-week caring behavior course at a Swedish university, were at the first and last week individually video-recorded during two caring behavior simulations with a standardized patient. After observing each of their video-recordings, students completed individual written reflection on their own verbal and nonverbal caring behavior. The written reflections were analyzed using qualitative content analysis. ConclusionSimulated encounters with standardized patients that visibly intertwine caring with nursing practice facilitates nursing students’ learning of compassionate and competent caring behaviorsThe learning experience made the students aware of the impact of practicing caring in nursing practice, recognizing that being with is not the same as doing for the patient, and thus, how challenging it is to be mindfully present in patient encountersVideo-recorded caring behavior simulations provide a feasible educational learning didactic, facilitating students’ learning to apply caring behaviors
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| 24. |
- Mårtensson, Sophie
(författare)
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Bridging the gap between caring theory and nursing practice : Learning experiences of undergraduate nursing students in a caring behavior course
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Healthcare providers are obligated to practice with scientific knowledge in order to deliver high quality and safe care based on patients’ needs. Despite this obligation, complaints from care recipients and their significant others regarding healthcare providers’ lack of compassion and competent care in their professional encounters have increased. In the discipline of nursing, theoretical structures of caring, conceptualized as behaviors, have been established as the heart and core value of guidance in all nursing practice. In nursing education, however, caring has tended to be taught as an intangible aspect of nursing practice, described as hidden curricula, thus, focus more on developing knowledge and psychomotor skills instead of learning caring behaviors. Studies that examine how undergraduate nursing students can learn caring behaviors explicitly are rare. Thus, a stronger emphasis on the learning of caring in the context of a caring behavior course that uses a variety of learning didactics is needed. Without adequate theoretical structures for caring-based observational behavioral instruments assessing verbal and non-verbal caring and non-caring behaviors, there is little evidence to help develop the learning of caring behaviors.Aim: The overall aim of this thesis was to study how a caring behavior course in undergraduate nursing education influenced students’ learning of caring behaviors.Method: This thesis was conducted among undergraduate nursing students at a university in Sweden. The participants attended a 7.5-credit (five-week) Caring Behavior Course (the CBC) in semester four during spring and fall 2018 and spring 2019. The CBC was facilitated through a student-centered learning approach intertwined into reflective practice with the learning didactics of narrative pedagogy and simulation; it comprised six voluntary lectures, five mandatory seminars, and two mandatory caring behavior simulation days and examinations. All data were collected from the students participating in the CBC. Two of the four scientific papers constituting this thesis had a qualitative design based on focus group interviews (paper I) and individual written reflections (paper II). Analyses was conducted using qualitative content analysis. One paper had an instrument development design to develop and test an observational behavioral instrument based on Swanson’s Theory of Caring (paper III). Lastly, one paper had a quantitative observational design using the CBCS on video-recorded observational behavioral data collected in the CBC (paper IV). Analyses was conducted using descriptive statistics and Wilcoxon signed rank test (paper IV).Results: The undergraduate nursing students’ participation in the CBC influenced their learning of caring behaviors. It deepened their understanding and knowledge of caring. The students became aware that learning caring is a task that requires effort because the meaning of caring encompasses nurses’ active engagement in practicing caring behaviors. These findings are also supported through the observational behavioral instrument, through the developed Caring Behavior Coding Scheme based on Swanson’s Theory of Caring; it was found that participation in the CBC influenced the undergraduate nursing students verbal and non-verbal caring and non-caring behaviors.Conclusions: This thesis demonstrated that bridging the gap between caring theory and nursing practice in the CBC using a variety of learning didactics influenced undergraduate nursing students’ learning of caring behaviors. The results contributed to strengthening the knowledge that caring and learning are parallel processes in the undergraduate nursing students’ development into becoming compassionate and competent caring nurses, with the intended outcome of patient healing and well-being.
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| 25. |
- Mårtensson, Sophie, et al.
(författare)
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Caring Behavior Coding Scheme based on Swanson’s Theory of Caring – development and testing among undergraduate nursing students
- 2021
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Ingår i: Scandinavian Journal of Caring Sciences. - : John Wiley & Sons. - 0283-9318 .- 1471-6712. ; 35:4, s. 1123-1133
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Tidskriftsartikel (refereegranskat)abstract
- Rationale: To maintain patients’ dignity and well-being and alleviate suffering, it is essential that healthcare providers engage in caring behaviours. Yet, every year patient boards receive an increasing number of complaints from patients and significant others regarding healthcare providers’ non-caring behaviours. Defining and measuring both verbal and nonverbal caring and non-caring behaviour in healthcare delivery is vital to address such complaints. However, no studies were found that incorporated a comprehensive theory of caring to code encounters between healthcare providers and patients.Aim: The aim was to develop and test a Caring Behavior Coding Scheme based on Swanson’s Theory of Caring.Method: An instrument development process was used for behavioural coding including observational data from thirty-eight video recordings collected in an undergraduate nursing course at a Swedish University. The observational data involved interactions between undergraduate nursing students and a standardised patient.Result: The Caring Behavior Coding Scheme (the CBCS), contains seventeen verbal and eight nonverbal behavioural codes, categorised as caring and non-caring in accordance with Swanson’s Theory of Caring. Content and face validity were assessed. Timed-event sequential continuous coding was performed in INTERACT software. The coder achieved excellent agreement with the developed gold standard (k = 0.87) and excellent mean inter-rater reliability (k = 0.82). All domains in Swanson’s Theory of Caring were observed and coded in the interaction.Discussion/Conclusion: The CBCS is a theory-based instrument that contributes to research on healthcare providers’ behavioural encounters. It uses verbal and nonverbal caring and non-caring behavioural codes to assess the alignment of both the theory and practice of caring. The CBCS can contribute to both development and measurement of interventions focused on improving healthcare providers’ caring behaviour with the intended outcome of patient well-being.
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| 26. |
- Mårtensson, Sophie, et al.
(författare)
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Development of caring behaviour in undergraduate nursing students participating in a caring behaviour course
- 2024
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Ingår i: Scandinavian Journal of Caring Sciences. - : John Wiley & Sons. - 0283-9318 .- 1471-6712. ; 38:1, s. 47-56
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Tidskriftsartikel (refereegranskat)abstract
- Background: In today's complex healthcare organisations there is an increasing recognition of the need to enhance care quality and patient safety. Nurses' competence in demonstrating caring behaviour during patient encounters affects how patients experience and participate in their care. Nurse educators are faced with the challenge of balancing the demand for increasingly complex knowledge and skills with facilitating students' abilities essential to becoming compassionate and caring nurses. Aim: The aim was to describe undergraduate nursing students' development of caring behaviour while participating in a caring behaviour course. Method: This pilot study used a quantitative observational design. At a university in Sweden, video-recorded observational data from twenty-five students were collected in the first and last weeks of a full-time five-week Caring Behaviour Course (the CBC). In total, 56-min video-recorded simulation interactions between a student and a standardised patient were coded by a credentialed coder using a timed-event sequential continuous coding method based on the Caring Behaviour Coding Scheme (the CBCS). The CBCS maps the five conceptual domains described in Swanson's Theory of Caring with related sub-domains that align with Swanson's qualities of the Compassionate Healer and the Competent Practitioner. The CBCS contains seventeen verbal and eight non-verbal behavioural codes, categorised as caring or non-caring. Results: Between the two simulations, most verbal caring behaviours increased, and most non-verbal caring behaviours decreased. Statistically significant differences between the simulations occurred in the sub-domains Avoiding assumptions and Performing competently/skilfully in the quality of the Competent Practitioner. Most observed caring behaviours aligned with the Compassionate Healer. Conclusion: Generally, the students' development of caring behaviours increased while participating in the CBC. Using a structured observational behavioural coding scheme can assist educators in assessing caring behaviour both in education and in practice, supporting caring as the universal foundation of nursing and a key to patient safety.
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| 27. |
- Mårtensson, Sophie Kjerstin, et al.
(författare)
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Undergraduate Nursing Students’ Experiences of Learning Caring Using a Variety of Learning Didactics
- 2022
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Ingår i: International journal for human caring. - : Springer Publishing Company. - 1091-5710 .- 2578-2304. ; 26:3, s. 145-158
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Tidskriftsartikel (refereegranskat)abstract
- This study examines undergraduate nursing students’ experiences of participating in a Caring Behavior Course using various learning didactics. Twenty-five students participated in one of five focus group interviews with data analyzed according to qualitative content analysis. The main theme to emerge, an insightful and sudden awakening that caring is not only theoretical words, was further explained with three themes and nine subthemes. The Caring Behavior Course demonstrates effective learning didactics to develop awareness of values that influence caring behaviors and can contribute to patient well-being, particularly relevant for the care challenges in the time of COVID-19 and beyond.
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| 28. |
- Mårtensson, Sophie, et al.
(författare)
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The Caring Behavior Coding Scheme : Development of an Observational Behavioral Scheme
- 2023
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Konferensbidrag (refereegranskat)abstract
- Motivation & AimIn today's complex healthcare organizations there is an increasing recognition of the need to enhance care quality and patient safety. Simultaneously, patient boards receive an increasing number of complaints from patients and significant others regarding healthcare providers’ non-caring behaviors. Defining and measuring both verbal and nonverbal caring and non-caring behavior in healthcare providers’ care delivery is vital to address such complaints. However, no studies were found that incorporated a comprehensive theory of caring to code encounters between healthcare providers and patients. Therefore, the aim was to develop and test a caring behavior coding scheme based on Swanson’s Theory of Caring.MethodAn instrument development process was used for behavioral coding including observational data from thirty-eight video recordings collected in an undergraduate nursing course at a Swedish University. The observational data depicts a six minutes simulated interaction between an undergraduate nursing student and a standardized patient focusing caring in nursing practice. ResultThe Caring Behavior Coding Scheme (the CBCS) entails eight nonverbal and seventeen verbal behavioral codes, categorized as caring and non-caring behaviors in accordance with Swanson’s Theory of Caring. Content validity was examined by Dr. Swanson, face validity was conducted by two clinical-nurses. A timed-event sequential continuous coding was performed in INTERACT®, the coder achieved excellent agreement with the developed gold standard (k = 0.87), and excellent mean inter-rater reliability (k = 0.82). The CBCS adequately captured caring behaviors as all domains in Swanson’s Theory of Caring were rated in the interaction.
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| 29. |
- Mårtensson, Sophie, et al.
(författare)
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Undergraduate Nursing Students' Experiences of Learning Caring Using a Variety of Learning Didactics
- 2022
-
Ingår i: International journal for human caring. - : Springer Publishing Company. - 1091-5710. ; 26:3, s. 145-158
-
Tidskriftsartikel (refereegranskat)abstract
- This study examines undergraduate nursing students' experiences of participating in a Caring Behavior Course using various learning didactics. Twenty-five students participated in one of five focus group interviews with data analyzed according to qualitative content analysis. The main theme to emerge, an insightful and sudden awakening that caring is not only theoretical words, was further explained with three themes and nine subthemes. The Caring Behavior Course demonstrates effective learning didactics to develop awareness of values that influence caring behaviors and can contribute to patient well-being, particularly relevant for the care challenges in the time of COVID-19 and beyond.
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| 30. |
- Mårtensson, Sophie, et al.
(författare)
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Undergraduate nursing students' experiences of practicing caring behaviours with standardised patients
- 2023
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Ingår i: Scandinavian Journal of Caring Sciences. - : John Wiley & Sons. - 0283-9318 .- 1471-6712. ; 37:1, s. 271-281
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Tidskriftsartikel (refereegranskat)abstract
- Rationale Undergraduate nursing students' learning opportunities to practice caring behaviours to assure compassionate and competent nursing practice with standardised patients are few. Earlier studies primarily focused on practicing communication skills in relation to mental health or developing psychomotor skills while caring for a patient with a specific diagnosis. Aim The study aim was to describe undergraduate nursing students' experiences of practicing caring behaviours with a standardised patient. Method A sample of forty-eight undergraduate nursing students in semester four at a school of nursing in southern Sweden, enrolled in a full-time, 5-week, on-campus elective caring behaviour course, were at the first and last week individually video-recorded during two caring behaviour simulations encountering a standardised patient. After observing each of their video-recordings, students completed written reflections focusing on their own compassionate and competent verbal and nonverbal caring behaviour. In total, 96 individual written reflections were analysed using qualitative content analysis to describe the experience. Results One main theme emerged: The challenge of being mindfully present in patient encounters. Four themes further described the experience: A challenging but realistic learning experience, learning the impact of nonverbal behaviour, recognising the complexity of verbal behaviour, and learning to be with the patient instead of only doing for the patient. Conclusion When caring is intertwined with visible and realistic nursing practice in simulations using standardised patients it facilitates undergraduate nursing students learning compassionate and competent caring behaviour. The learning experience opened the students' eyes to the impact of practicing caring, recognising that being with is not the same as doing for the patient, and thus, how challenging it is to be mindfully present in patient encounters. Designing caring behaviour simulations with standardised patients is a feasible and efficacious educational learning didactic to facilitate students' learning caring behaviour and enhancing patients' experiences.
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| 31. |
- Nordgren, Bengt, et al.
(författare)
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Postpolio muscular dysfunction : relationships between muscle energy metabolism, subjective symptoms, magnetic resonance imaging, electromyography, and muscle strength
- 1997
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Ingår i: Muscle and Nerve. - 0148-639X .- 1097-4598. ; 20:11, s. 1341-1351
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Tidskriftsartikel (refereegranskat)abstract
- Eleven patients with previous polio were studied. The concentration of energy-related metabolites and energy charge was measured from the vastus lateralis muscle, as was isometric muscle strength of knee extension. Cross-sectional area of the quadriceps femoris muscle was calculated from magnetic resonance imaging. Reinnervation was studied using macroelectromyography. Muscle weakness, pain, and newly acquired muscle weakness in the legs was estimated by the patients. The findings in the legs in which the patients experienced new loss of muscle function were compared with the stable legs. There were no significant differences between these groups in any of the objectively measured variables. Only hip pain correlated with new loss of muscle function. Creatine phosphate was decreased in 5 patients. The symptoms and subjective muscle strength did not correlate with any of the objective measurements. There were no significant relationships between energy-related metabolites and postpolio symptoms.
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| 32. |
- Rubio, Carlos A., et al.
(författare)
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Quantitative assessment of the subepithelial collagen band does not increase the accuracy of diagnosis of collagenous colitis
- 2008
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Ingår i: American Journal of Clinical Pathology. - 0002-9173 .- 1943-7722. ; 130:3, s. 375-381
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Tidskriftsartikel (refereegranskat)abstract
- The thickness of eosinophilic band in collagenous colitis (CC) was assessed by 3 methods: histologic estimates (22 observers), conventional measurements using a calibrated micrometric scale (1 observer), and semiautomatic micrometric measurements (1 observer). By the histologic estimate technique, 7.4% of the results failed to diagnose CC; by calibrated micrometry, the failure was 6% and by semiautomatic micrometry, 6%. The main difficulty in measuring the thickness of the CC band is that the deeper border of the band appears fuzzy and hairy-irregular. CC should be defined not exclusively on the basis of the thickness of the collagen table, but as a microscopic constellation characterized by a distorted superficial cell arrangement, with areas of epithelial denudation and inflammatory cells in the superficial epithelium and the lamina propria. In agreement with Lazenby's statement: "Focusing solely on the collagen band can result in both over- and underdiagnosis"
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| 33. |
- Wilhelms, Daniel Björk, et al.
(författare)
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Deletion of Prostaglandin E-2 Synthesizing Enzymes in Brain Endothelial Cells Attenuates Inflammatory Fever
- 2014
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Ingår i: Journal of Neuroscience. - : Society for Neuroscience. - 0270-6474 .- 1529-2401. ; 34:35, s. 11684-11690
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Tidskriftsartikel (refereegranskat)abstract
- Fever is a hallmark of inflammatory and infectious diseases. The febrile response is triggered by prostaglandin E-2 synthesis mediated by induced expression of the enzymes cyclooxygenase-2 (COX-2) and microsomal prostaglandin E synthase 1 (mPGES-1). The cellular source for pyrogenic PGE(2) remains a subject of debate; several hypotheses have been forwarded, including immune cells in the periphery and in the brain, as well as the brain endothelium. Here we generated mice with selective deletion of COX-2 and mPGES1 in brain endothelial cells. These mice displayed strongly attenuated febrile responses to peripheral immune challenge. In contrast, inflammation-induced hypoactivity was unaffected, demonstrating the physiological selectivity of the response to the targeted gene deletions. These findings demonstrate that PGE(2) synthesis in brain endothelial cells is critical for inflammation-induced fever.
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