| 1. |
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| 2. |
- Adén, Daniel, et al.
(författare)
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A photometric and spectroscopic study of the new dwarf spheroidal galaxy in Hercules. Metallicity, velocities and a clean list of RGB members
- 2009
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Ingår i: Astronomy & Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 506:3, s. 1147-1168
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Tidskriftsartikel (refereegranskat)abstract
- Our aim is to provide as clean and as complete a sample as possible of red giant branch stars that are members of the Hercules dSph galaxy. With this sample we explore the velocity dispersion and the metallicity of the system. Stromgren photometry and multi-fibre spectroscopy are combined to provide information about the evolutionary state of the stars (via the Stromgren c_1 index) and their radial velocities. Based on this information we have selected a clean sample of red giant branch stars, and show that foreground contamination by Milky Way dwarf stars can greatly distort the results. Our final sample consists of 28 red giant branch stars in the Hercules dSph galaxy. Based on these stars we find a mean photometric metallicity of -2.35 dex which is consistent with previous studies. We find evidence for an abundance spread. Using those stars for which we have determined radial velocities we find a systemic velocity of 45.2 km/s with a dispersion of 3.72 km/s, this is lower than values found in the literature. Furthermore we identify the horizontal branch and estimate the mean magnitude of the horizontal branch of the Hercules dSph galaxy to be V_0=21.17, which corresponds to a distance of 147 kpc. We have shown that a proper cleaning of the sample results in a smaller value for the velocity dispersion of the system. This has implications for galaxy properties derived from such velocity dispersions.
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| 3. |
- Adén, Daniel, et al.
(författare)
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An abundance study of red-giant-branch stars in the Hercules dwarf spheroidal galaxy
- 2011
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 525, s. A153-
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Tidskriftsartikel (refereegranskat)abstract
- Context. Dwarf spheroidal galaxies are some of the most metal-poor, and least luminous objects known. Detailed elemental abundance analysis of stars in these faint objects is key to our understanding of star formation and chemical enrichment in the early universe, and may provide useful information on how larger galaxies form. Aims. Our aim is to provide a determination of [Fe/H] and [Ca/H] for confirmed red-giant branch member stars of the Hercules dwarf spheroidal galaxy. Based on this we explore the ages of the prevailing stellar populations in Hercules, and the enrichment history from supernovae. Additionally, we aim to provide a new simple metallicity calibration for Stromgren photometry for metal-poor, red giant branch stars. Methods. High-resolution, multi-fibre spectroscopy and Stromgren photometry are combined to provide as much information on the stars as possible. From this we derive abundances by solving the radiative transfer equations through marcs model atmospheres. Results. We find that the red-giant branch stars of the Hercules dSph galaxy are more metal-poor than estimated in our previous study that was based on photometry alone. From this, we derive a new metallicity calibration for the Stromgren photometry. Additionally, we find an abundance trend such that [Ca/Fe] is higher for more metal-poor stars, and lower for more metal-rich stars, with a spread of about 0.8 dex. The [Ca/Fe] trend suggests an early rapid chemical enrichment through supernovae of type II, followed by a phase of slow star formation dominated by enrichment through supernovae of type Ia. A comparison with isochrones indicates that the red giants in Hercules are older than 10 Gyr.
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| 4. |
- Auffret, Alistair G., et al.
(författare)
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More warm-adapted species in soil seed banks than in herb layer plant communities across Europe
- 2023
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Ingår i: Journal of Ecology. - : John Wiley & Sons. - 0022-0477 .- 1365-2745. ; 111:5, s. 1009-1020
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Tidskriftsartikel (refereegranskat)abstract
- Responses to climate change have often been found to lag behind the rate of warming that has occurred. In addition to dispersal limitation potentially restricting spread at leading range margins, the persistence of species in new and unsuitable conditions is thought to be responsible for apparent time-lags. Soil seed banks can allow plant communities to temporarily buffer unsuitable environmental conditions, but their potential to slow responses to long-term climate change is largely unknown. As local forest cover can also buffer the effects of a warming climate, it is important to understand how seed banks might interact with land cover to mediate community responses to climate change. We first related species-level seed bank persistence and distribution-derived climatic niches for 840 plant species. We then used a database of plant community data from grasslands, forests and intermediate successional habitats from across Europe to investigate relationships between seed banks and their corresponding herb layers in 2763 plots in the context of climate and land cover. We found that species from warmer climates and with broader distributions are more likely to have a higher seed bank persistence, resulting in seed banks that are composed of species with warmer and broader climatic distributions than their corresponding herb layers. This was consistent across our climatic extent, with larger differences (seed banks from even warmer climates relative to vegetation) found in grasslands. Synthesis. Seed banks have been shown to buffer plant communities through periods of environmental variability, and in a period of climate change might be expected to contain species reflecting past, cooler conditions. Here, we show that persistent seed banks often contain species with relatively warm climatic niches and those with wide climatic ranges. Although these patterns may not be primarily driven by species’ climatic adaptations, the prominence of such species in seed banks might still facilitate climate-driven community shifts. Additionally, seed banks may be related to ongoing trends regarding the spread of widespread generalist species into natural habitats, while cool-associated species may be at risk from both short- and long-term climatic variability and change.
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| 5. |
- Belova, Valentina, et al.
(författare)
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Evidence for Anisotropic Electronic Coupling of Charge Transfer States in Weakly Interacting Organic Semiconductor Mixtures
- 2017
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 139:25, s. 8474-8486
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Tidskriftsartikel (refereegranskat)abstract
- We present a comprehensive investigation of the charge-transfer (CT) effect in weakly interacting organic semiconductor mixtures. The donor-acceptor pair diindenoperylene (DIP) and N,N′-bis(2-ethylhexyl)-1,7-dicyanoperylene-3,4/9,10-bis(dicarboxyimide) (PDIR-CN2) has been chosen as a model system. A wide range of experimental methods was used in order to characterize the structural, optical, electronic, and device properties of the intermolecular interactions. By detailed analysis, we demonstrate that the partial CT in this weakly interacting mixture does not have a strong effect on the ground state and does not generate a hybrid orbital. We also find a strong CT transition in light absorption as well as in photo- and electroluminescence. By using different layer sequences and compositions, we are able to distinguish electronic coupling in-plane vs out-of-plane and, thus, characterize the anisotropy of the CT state. Finally, we discuss the impact of CT exciton generation on charge-carrier transport and on the efficiency of photovoltaic devices.
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| 6. |
- Caffau, E., et al.
(författare)
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Velocity and abundance precisions for future high-resolution spectroscopic surveys: A study for 4MOST
- 2013
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Ingår i: Astronomical Notes - Astronomische Nachrichten. - : Wiley. - 0004-6337. ; 334:3, s. 197-216
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Tidskriftsartikel (refereegranskat)abstract
- In preparation for future, large-scale, multi-object, high-resolution spectroscopic surveys of the Galaxy, we present a series of tests of the precision in radial velocity and chemical abundances that any such project can achieve at a 4 m class telescope. We briefly discuss a number of science cases that aim at studying the chemo-dynamical history of the major Galactic components (bulge, thin and thick disks, and halo) - either as a follow-up to the Gaia mission or on their own merits. Based on a large grid of synthetic spectra that cover the full range in stellar parameters of typical survey targets, we devise an optimal wavelength range and argue for a moderately high-resolution spectrograph. As a result, the kinematic precision is not limited by any of these factors, but will practically only suffer from systematic effects, easily reaching uncertainties <1km s(-1). Under realistic survey conditions (namely, considering stars brighter than r = 16 mag with reasonable exposure times) we prefer an ideal resolving power of R similar to 20 000 on average, for an overall wavelength range (with a common two-arm spectrograph design) of [395;456.5] nm and [587; 673] nm. We show for the first time on a general basis that it is possible to measure chemical abundance ratios to better than 0.1 dex for many species (Fe, Mg, Si, Ca, Ti, Na, Al, V, Cr, Mn, Co, Ni, Y, Ba, Nd, Eu) and to an accuracy of about 0.2 dex for other species such as Zr, La, and Sr. While our feasibility study was explicitly carried out for the 4MOST facility, the results can be readily applied to and used for any other conceptual design study for high-resolution spectrographs. (C) 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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| 7. |
- de Jong, Roelof S., et al.
(författare)
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4MOST-4-metre Multi-Object Spectroscopic Telescope
- 2014
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Ingår i: Ground-based and Airborne Instrumentation for Astronomy V. - : SPIE. - 0277-786X .- 1996-756X. ; 9147
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Konferensbidrag (refereegranskat)abstract
- 4MOST is a wide-field, high-multiplex spectroscopic survey facility under development for the VISTA telescope of the European Southern Observatory (ESO). Its main science drivers are in the fields of galactic archeology, high-energy physics, galaxy evolution and cosmology. 4MOST will in particular provide the spectroscopic complements to the large area surveys coming from space missions like Gaia, eROSITA, Euclid, and PLATO and from ground-based facilities like VISTA, VST, DES, LSST and SKA. The 4MOST baseline concept features a 2.5 degree diameter field-of-view with similar to 2400 fibres in the focal surface that are configured by a fibre positioner based on the tilting spine principle. The fibres feed two types of spectrographs; similar to 1600 fibres go to two spectrographs with resolution R> 5000 (lambda similar to 390-930 nm) and similar to 800 fibres to a spectrograph with R> 18,000 (lambda similar to 392-437 nm & 515-572 nm & 605-675 nm). Both types of spectrographs are fixed-configuration, three-channel spectrographs. 4MOST will have an unique operations concept in which 5 year public surveys from both the consortium and the ESO community will be combined and observed in parallel during each exposure, resulting in more than 25 million spectra of targets spread over a large fraction of the southern sky. The 4MOST Facility Simulator (4FS) was developed to demonstrate the feasibility of this observing concept. 4MOST has been accepted for implementation by ESO with operations expected to start by the end of 2020. This paper provides a top-level overview of the 4MOST facility, while other papers in these proceedings provide more detailed descriptions of the instrument concept[1], the instrument requirements development[2], the systems engineering implementation[3], the instrument model[4], the fibre positioner concepts[5], the fibre feed[6], and the spectrographs[7].
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| 8. |
- Forsberg, Simon, et al.
(författare)
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The Shepherds' Tale : A Genome-Wide Study across 9 Dog Breeds Implicates Two Loci in the Regulation of Fructosamine Serum Concentration in Belgian Shepherds
- 2015
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 10:5
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Tidskriftsartikel (refereegranskat)abstract
- Diabetes mellitus is a serious health problem in both dogs and humans. Certain dog breeds show high prevalence of the disease, whereas other breeds are at low risk. Fructosamine and glycated haemoglobin (HbA1c) are two major biomarkers of glycaemia, where serum concentrations reflect glucose turnover over the past few weeks to months. In this study, we searched for genetic factors influencing variation in serum fructosamine concentration in healthy dogs using data from nine dog breeds. Considering all breeds together, we did not find any genome-wide significant associations to fructosamine serum concentration. However, by performing breed-specific analyses we revealed an association on chromosome 3 (rho(corrected) approximate to 1:68 x 10(-6)) in Belgian shepherd dogs of the Malinois subtype. The associated region and its close neighbourhood harbours interesting candidate genes such as LETM1 and GAPDH that are important in glucose metabolism and have previously been implicated in the aetiology of diabetes mellitus. To further explore the genetics of this breed specificity, we screened the genome for reduced heterozygosity stretches private to the Belgian shepherd breed. This revealed a region with reduced heterozygosity that shows a statistically significant interaction (rho = 0.025) with the association region on chromosome 3. This region also harbours some interesting candidate genes and regulatory regions but the exact mechanisms underlying the interaction are still unknown. Nevertheless, this finding provides a plausible explanation for breed-specific genetic effects for complex traits in dogs. Shepherd breeds are at low risk of developing diabetes mellitus. The findings in Belgian shepherds could be connected to a protective mechanism against the disease. Further insight into the regulation of glucose metabolism could improve diagnostic and therapeutic methods for diabetes mellitus.
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| 9. |
- Frank, Matthias J., et al.
(författare)
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Stromgren uvby photometry of the peculiar globular cluster NGC 2419
- 2015
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Ingår i: Astronomy & Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 581
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Tidskriftsartikel (refereegranskat)abstract
- NGC 2419 is a peculiar Galactic globular cluster off set from the others in the size-luminosity diagram, and showing several chemical abundance anomalies. Here, we present Stromgren uvby photometry of the cluster. Using the gravity-and metallicity-sensitive c(1) and m(1) indices, we identify a sample of likely cluster members extending well beyond the formal tidal radius. The estimated contamination by cluster non-members is only one per cent, making our catalogue ideally suited for spectroscopic follow-up. We derive photometric [Fe/H] of red giants, and depending on which metallicity calibration from the literature we use, we find reasonable to excellent agreement with spectroscopic [Fe/H], both for the cluster mean metallicity and for individual stars. We demonstrate explicitly that the photometric uncertainties are not Gaussian and this must be accounted for in any analysis of the metallicity distribution function. Using a realistic, non-Gaussian model for the photometric uncertainties, we find a formal internal [Fe/H] spread of sigma = 0.11(-0.01)(+0.02) dex. This is an upper limit to the cluster's true [Fe/H] spread and may partially, and possibly entirely, reflect the limited precision of the photometric metallicity estimation and systematic effects. The lack of correlation between spectroscopic and photometric [Fe/H] of individual stars is further evidence against a [Fe/H] spread on the 0.1 dex level. Finally, the CN-sensitive delta(4), among other colour indices, anti-correlates strongly with magnesium abundance, indicating that the second-generation stars are nitrogen enriched. The absence of similar correlations in some other CN-sensitive indices supports the second generation being enriched in He, which in these indices approximately compensates the shift due to CN. Compared to a single continuous distribution with finite dispersion, the observed delta(4) distribution of red giants is slightly better fit by two distinct populations with no internal spread, with the nitrogen-enhanced second generation accounting for 53 +/- 5 per cent of stars. Despite its known peculiarities, NGC 2419 appears to be very similar to other metal-poor Galactic globular clusters with a similarly nitrogen-enhanced second generation and little or no variation in [Fe/H], which sets it apart from other suspected accreted nuclei such as omega Cen.
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| 10. |
- Gilmore, G., et al.
(författare)
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The Gaia-ESO Public Spectroscopic Survey : Motivation, implementation, GIRAFFE data processing, analysis, and final data products star
- 2022
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 666
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Tidskriftsartikel (refereegranskat)abstract
- Context. The Gaia-ESO Public Spectroscopic Survey is an ambitious project designed to obtain astrophysical parameters and elemental abundances for 100 000 stars, including large representative samples of the stellar populations in the Galaxy, and a well-defined sample of 60 (plus 20 archive) open clusters. We provide internally consistent results calibrated on benchmark stars and star clusters, extending across a very wide range of abundances and ages. This provides a legacy data set of intrinsic value, and equally a large wide-ranging dataset that is of value for the homogenisation of other and future stellar surveys and Gaia's astrophysical parameters. Aims. This article provides an overview of the survey methodology, the scientific aims, and the implementation, including a description of the data processing for the GIRAFFE spectra. A companion paper introduces the survey results. Methods. Gaia-ESO aspires to quantify both random and systematic contributions to measurement uncertainties. Thus, all available spectroscopic analysis techniques are utilised, each spectrum being analysed by up to several different analysis pipelines, with considerable effort being made to homogenise and calibrate the resulting parameters. We describe here the sequence of activities up to delivery of processed data products to the ESO Science Archive Facility for open use. Results. The Gaia-ESO Survey obtained 202 000 spectra of 115 000 stars using 340 allocated VLT nights between December 2011 and January 2018 from GIRAFFE and UVES. Conclusions. The full consistently reduced final data set of spectra was released through the ESO Science Archive Facility in late 2020, with the full astrophysical parameters sets following in 2022. A companion article reviews the survey implementation, scientific highlights, the open cluster survey, and data products.
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| 11. |
- Hansen, C. J., et al.
(författare)
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Stellar science from a blue wavelength range
- 2015
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Ingår i: Russian Review. - : Wiley. - 1467-9434. ; 74:4, s. 665-676
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Tidskriftsartikel (refereegranskat)abstract
- From stellar spectra, a variety of physical properties of stars can be derived. In particular, the chemical composition of stellar atmospheres can be inferred from absorption line analyses. These provide key information on large scales, such as the formation of our Galaxy, down to the small-scale nucleosynthesis processes that take place in stars and supernovae. By extending the observed wavelength range toward bluer wavelengths, we optimize such studies to also include critical absorption lines in metal-poor stars, and allow for studies of heavy elements (Z = 38) whose formation processes remain poorly constrained. In this context, spectrographs optimized for observing blue wavelength ranges are essential, since many absorption lines at redder wavelengths are too weak to be detected in metal-poor stars. This means that some elements cannot be studied in the visual-redder regions, and important scientific tracers and science cases are lost. The present era of large public surveys will target millions of stars. It is therefore important that the next generation of spectrographs are designed such that they cover a wide wavelength range and can observe a large number of stars simultaneously. Only then, we can gain the full information from stellar spectra, from both metal-poor to metal-rich ones, that will allow us to understand the aforementioned formation scenarios in greater detail. Here we describe the requirements driving the design of the forthcoming survey instrument 4MOST, a multi-object spectrograph commissioned for the ESO VISTA 4 m-telescope. While 4MOST is also intended for studies of active galactic nuclei, baryonic acoustic oscillations, weak lensing, cosmological constants, supernovae and other transients, we focus here on high-density, wide-area survey of stars and the science that can be achieved with high-resolution stellar spectroscopy. Scientific and technical requirements that governed the design are described along with a thorough line blending analysis. For the high-resolution spectrograph, we find that a sampling of >= 2.5 (pixels per resolving element), spectral resolution of 18 000 or higher, and a wavelength range covering 393-436 nm, is the most well-balanced solution for the instrument. A spectrograph with these characteristics will enable accurate abundance analysis (+/- 0.1 dex) in the blue and allow us to confront the outlined scientific questions. (C) 2015 WILEY-VCH Verlag GmbH& Co. KGaA, Weinheim
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| 12. |
- Håglin, Sofia, et al.
(författare)
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APOE ɛ4, but not polygenic Alzheimer’s disease risk, is related to longitudinal decrease in hippocampal brain activity in non-demented individuals
- 2023
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- The hippocampus is affected early in Alzheimer’s disease (AD) and altered hippocampal functioning influences normal cognitive aging. Here, we used task-based functional MRI to assess if the APOE ɛ4 allele or a polygenic risk score (PRS) for AD was linked to longitudinal changes in memory-related hippocampal activation in normal aging (baseline age 50–95, n = 292; n = 182 at 4 years follow-up, subsequently non-demented for at least 2 years). Mixed-models were used to predict level and change in hippocampal activation by APOE ɛ4 status and PRS based on gene variants previously linked to AD at p ≤ 1, p < 0.05, or p < 5e−8 (excluding APOE). APOE ɛ4 and PRSp<5e−8 significantly predicted AD risk in a larger sample from the same study population (n = 1542), while PRSp≤1 predicted memory decline. APOE ɛ4 was linked to decreased hippocampal activation over time, with the most prominent effect in the posterior hippocampi, while PRS was unrelated to hippocampal activation at all p-thresholds. These results suggests a link for APOE ɛ4, but not for AD genetics in general, on functional changes of the hippocampi in normal aging.
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| 13. |
- Hörmann, Ulrich, et al.
(författare)
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Voc from a Morphology Point of View : the Influence of Molecular Orientation on the Open Circuit Voltage of Organic Planar Heterojunction Solar Cells
- 2014
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Ingår i: Journal of physical chemistry C. - : American Chemical Society (ACS). - 1932-7455 .- 1932-7447. ; 118:46, s. 26462-26470
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Tidskriftsartikel (refereegranskat)abstract
- The film morphology and device performance of planar heterojunctionsolar cells based on the molecular donor material α-sexithiophene (6T) are investigated.Planar heterojunctions of 6T with two different acceptor molecules, the C60 fullerene anddiindenoperylene (DIP), have been prepared. The growth temperature of the 6T bottomlayer has been varied between room temperature and 100 °C for each acceptor. By meansof X-ray diffraction and X-ray absorption, we show that the crystallinity and the molecularorientation of 6T is influenced by the preparation conditions and that the 6T filmtemplates the growth of the subsequent acceptor layer. These structural changes areaccompanied by changes in the characteristic parameters of the correspondingphotovoltaic cells. This is most prominently observed as a shift of the open circuitvoltage (Voc): In the case of 6T/C60 heterojunctions, Voc decreases from 0.4 to 0.3 V,approximately, if the growth temperature of 6T is increased from room temperature to 100°C. By contrast, Voc increases from about 1.2 V to almost 1.4 V in the case of 6T/DIP solarcells under the same conditions. We attribute these changes upon substrate heating toincreased recombination in the C60 case while an orientation dependent intermolecular coupling seems to change the origin of the photovoltaic gap in the DIP case.
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| 14. |
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| 15. |
- Jonasson, Sofia, et al.
(författare)
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Inhalation exposure of nano-scaled titanium dioxide (TiO2) particles alters the inflammatory responses in asthmatic mice
- 2013
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Ingår i: Inhalation Toxicology. - : Informa Healthcare. - 0895-8378 .- 1091-7691. ; 25:4, s. 179-191
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Tidskriftsartikel (refereegranskat)abstract
- Context: Titanium dioxide (TiO2) nanoparticles (NPs) are regarded as relatively non-toxic in concentrations occurring in occupational environments. Nevertheless, it is conceivable that adverse health effects may develop in sensitive populations such as individuals with respiratory diseases.Objective: We investigated whether single or repeated exposure to TiO2 could aggravate inflammatory responses in naive mice and mice with ovalbumin (OVA)-induced airway inflammation.Methods: Exposure to aerosolized TiO2 was performed during OVA sensitization, before, or during the OVA challenge period. The effects on respiratory physiology, inflammatory cells in bronchoalveolar lavage (BAL) and inflammatory mediators in BAL and serum were assessed 24 h after the last OVA challenge or TiO2 exposure.Results: A single exposure of TiO2 had a marked effect on responses in peripheral airways and increasing infiltration of neutrophils in airways of naive animals. Marked aggravation of airway responses was also observed in animals with allergic disease provided that the single dose TiO2 was given before allergen challenge. Repeated exposures to TiO2 during sensitization diminished the OVA-induced airway eosinophilia and airway hyperresponsiveness but concomitant exposure to TiO2 during the OVA challenge period resulted in neutrophilic airway inflammation and a decline in general health condition as indicated by the loss of body weight.Conclusion: We conclude that inhalation of TiO2 may aggravate respiratory diseases and that the adverse health effects are highly dependent on dose and timing of exposure. Our data imply that inhalation of NPs may increase the risk for individuals with allergic airway disease to develop symptoms of severe asthma.
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| 16. |
- Koch, Andreas, et al.
(författare)
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A Spectroscopic Binary in the Hercules Dwarf Spheroidal Galaxy
- 2014
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Ingår i: Astrophysical Journal. - 0004-637X. ; 780:1
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Tidskriftsartikel (refereegranskat)abstract
- We present the radial velocity curve of a single-lined spectroscopic binary in the faint Hercules dwarf spheroidal (dSph) galaxy, based on 34 individual spectra covering more than 2 yr of observations. This is the first time that orbital elements could be derived for a binary in a dSph. The system consists of a metal-poor red giant and a low-mass companion, possibly a white dwarf, with a 135 day period in a moderately eccentric (e = 0.18) orbit. Its period and eccentricity are fully consistent with metal-poor binaries in the Galactic halo, while the projected semimajor axis is small, at a(p) sin i = 38 R-circle dot. In fact, a very close orbit could inhibit the production of heavier elements through s-process nucleosynthesis, leading to the very low abundances of neutron-capture elements that are found in this star. We discuss the further implications for the chemical enrichment history of the Hercules dSph, but find no compelling binary scenario that could reasonably explain the full, peculiar abundance pattern of the Hercules dSph galaxy.
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| 17. |
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| 18. |
- Koch, A., et al.
(författare)
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Neutron-capture element deficiency of the Hercules dwarf spheroidal galaxy
- 2013
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Ingår i: Astronomy & Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 554
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Tidskriftsartikel (refereegranskat)abstract
- We present an assessment of the barium abundance ratios for red giant member stars in the faint Hercules dwarf spheroidal (dSph) galaxy. Our results are drawn from intermediate-resolution FLAMES/GIRAFFE spectra around the Ba II 6141.71 angstrom absorption line at low signal-to-noise ratios. For three brighter stars we were able to gain estimates from direct equivalent-width measurements, while for the remaining eight stars only upper limits could be obtained. These results are investigated in a statistical manner and indicate very low Ba abundances of log epsilon(Ba) less than or similar to 0.7 dex (3 sigma). We discuss various possible systematic biasses, first and foremost, a blend with the Fe I 6141.73 angstrom-line, but most of those would only lead to even lower abundances. A better match with metal-poor halo and dSph stars can only be reached by including a large uncertainty in the continuum placement. This contrasts with the high dispersions in iron and calcium (in excess of 1 dex) in this galaxy. While the latter spreads are typical of the very low luminosity, dark-matter dominated dSphs, a high level of depletion in heavy elements suggests that chemical enrichment in Hercules was governed by very massive stars, coupled with a very low star formation efficiency. While very low abundances of some heavy elements are also found in individual stars of other dwarf galaxies, this is the first time that a very low Ba abundance is found within an entire dSph over a broad metallicity range.
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| 19. |
- Koch, Christian, et al.
(författare)
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Plant versus Cow: Conflict Framing in the Ant/Agonistic Relegitimization of a Market
- 2022
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Ingår i: Journal of Macromarketing. - : SAGE Publications. - 0276-1467 .- 1552-6534. ; 42:2, s. 247-261
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Tidskriftsartikel (refereegranskat)abstract
- In this article we focus on the cultural mechanisms of market evolution accompanying the marketplace discord between a market actor and a dominant industry. We situate our analysis in the intersection between marketing and institutional theory and engage specifically with the constructs of legitimacy and framing strategies, but also with Chantal Mouffe’s political philosophy concept of agonistics. To better understand the blurry impact of market-driven activism and conflict on the shaping of markets, we use the ongoing “milk-war” between plant- versus animal-based drink producers as backdrop, and empirically explore how a market actor and their supporting institutional actors frame a previously legitimate industry in an attempt to delegitimize it, without sacrificing its consumer market. We find a rhetorical juggling-act of attempted legitimization of the market alternative and delegitimization of the status quo, where the intricacy of framing strategies constitutes what we call conflict framing. In line with the market-critical fundaments of agonistics, this conflict framing can work to (partly) delegitimize the status quo industry and to relegitimize its market at the same time, but cannot radically disrupt the system. Drawing from research predicting a growing absorption of politicized conflict by the market in general, we problematize and critique a potential rise in presence of marketmediated conflict framing. Our insights contribute to ongoing conversations on market evolution, markets for alternatives, ethical consumption and the ideological functioning of markets.
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| 20. |
- Lindström, Sofia
(författare)
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The art of being for real
- 2013
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- The Art of Being for Real opens up new paths and perspectives concerning the right of children and young people to self-expression. Young & Creative is an example of young people having access to a place in which to meet and express themselves artistically. The setting for this was Röda Sten Art Centre in Gothenburg. While the meeting between young people was a founding concept, the project also had certain pedagogically groundbreaking aspects in that it brought together two different professions - social workers and art pedagogues. These two groups met head on with a great deal of courage and, working alongside the young people, developed an approach and methodology to nurture creative energy. This exciting project had earlier been assessed by Sofia Lindström. The reader is now able to partake of the lessons of her assessment, as presented in this booklet.
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| 21. |
- Lundholm, Nina, et al.
(författare)
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Buried alive - Germination of up to a century-old marine protist resting stages
- 2011
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Ingår i: Phycologia. - : Informa UK Limited. - 0031-8884 .- 2330-2968. ; 50:6, s. 629-640
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Tidskriftsartikel (refereegranskat)abstract
- report on the survival and germination of up to a century-old marine protist resting stages naturally preserved insediments from Koljö Fjord on the west coast of Sweden. This work has focused on germination of dinoflagellate cysts,but diatom resting stages were also observed. We record the longest known survival of dormant dinoflagellate cells. Weindividually isolated more than 1200 cysts of the three most abundant dinoflagellate taxa: Pentapharsodinium dalei,Lingulodinium polyedrum and Scrippsiella spp. Germination success decreased with core depth, and all successfulgerminations took place within the first 2 wk of incubation. Pentapharsodinium dalei had the highest germination successrate, with a maximum of up to 80% in 28-yr-old sediment, and could successfully germinate from core sediments datedto 1920 ± 12. Scrippsiella spp. cysts with cell contents occurred down to c. 90-yr-old sediment and could germinate fromdown to ca. 40-yr-old sediments, with a maximum germination rate of 50-60% in recent sediments. Cysts of L.polyedrum germinated frequently down to 20 yr and rarely to c. 80 yr, with a maximum of 20-50% germination successin recent sediments. Cyst isolation under cooled conditions rather than at room temperature resulted in a significantlyhigher germination success in P. dalei, while no effect was observed for L. polyedrum. The time elapsed since slicing ofthe core affected survival of L. polyedrum cysts negatively, most likely due to the effect of oxygen. The long-termsurvival potential of benthic resting stages that we report here has important implications, as viable resting stagesaccumulated in bottom sediments can be transported back to the water column by, for example, bioturbation andhuman-mediated sediment dredging. Hence, the sediment may to a higher degree than previously considered play a roleas seed bank. This is important in a changing climate and might have particularly severe impacts in the case of harmful species.
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| 22. |
- Moberg, Christina, et al.
(författare)
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De unga gör helt rätt när de stämmer staten
- 2022
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Ingår i: Aftonbladet. - 1103-9000.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- 1 620 forskare och lärare i forskarvärlden: Vi ställer oss bakom Auroras klimatkrav
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| 23. |
- Omazic, Anna, et al.
(författare)
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Identifying climate-sensitive infectious diseases in animals and humans in Northern regions
- 2019
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Ingår i: Acta Veterinaria Scandinavica. - : BioMed Central. - 0044-605X .- 1751-0147. ; 61:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: General knowledge on climate change effects and adaptation strategies has increased significantly in recent years. However, there is still a substantial information gap regarding the influence of climate change on infectious diseases and how these diseases should be identified. From a One Health perspective, zoonotic infections are of particular concern. The climate in Northern regions is changing faster than the global average. This study sought to identify climate-sensitive infectious diseases (CSIs) of relevance for humans and/or animals living in Northern regions. Inclusion criteria for CSIs were constructed using expert assessments. Based on these principles, 37 potential CSIs relevant for Northern regions were identified. A systematic literature search was performed in three databases using an explicit stepwise approach to determine whether the literature supports selection of these 37 potential CSIs.Results: In total, 1275 nominated abstracts were read and categorised using predefined criteria. Results showed that arthropod vector-borne diseases in particular are recognised as having potential to expand their distribution towards Northern latitudes and that tick-borne encephalitis and borreliosis, midge-borne bluetongue and the parasitic infection fasciolosis can be classified as climate-sensitive. Many of the other potential CSIs considered are affected by extreme weather events, but could not be clearly classified as climate-sensitive. An additional literature search comparing awareness of climate influences on potential CSIs between 1997-2006 and 2007-2016 showed an increase in the number of papers mentioning effects of climate change.Conclusions: The four CSIs identified in this study could be targeted in a systematic surveillance programme in Northern regions. It is evident that climate change can affect the epidemiology and geographical range of many infectious diseases, but there were difficulties in identifying additional CSIs, most likely because other factors may be of equal or greater importance. However, climate-ecological dynamics are constantly under change, and therefore diseases may fall in or out of the climate-sensitive definition over time. There is increasing awareness in the literature of the effects of climate change on infectious diseases over time.
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| 24. |
- Plue, Jan, et al.
(författare)
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Buffering effects of soil seed banks on plant community composition in response to land use and climate
- 2020
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Ingår i: Global Ecology and Biogeography. - : Wiley. - 1466-822X .- 1466-8238. ; 30:1, s. 128-139
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Tidskriftsartikel (refereegranskat)abstract
- AimClimate and land use are key determinants of biodiversity, with past and ongoing changes posing serious threats to global ecosystems. Unlike most other organism groups, plant species can possess dormant life‐history stages such as soil seed banks, which may help plant communities to resist or at least postpone the detrimental impact of global changes. This study investigates the potential for soil seed banks to achieve this.Location Europe.Time period 1978–2014.Major taxa studied Flowering plantsMethodsUsing a space‐for‐time/warming approach, we study plant species richness and composition in the herb layer and the soil seed bank in 2,796 community plots from 54 datasets in managed grasslands, forests and intermediate, successional habitats across a climate gradient.ResultsSoil seed banks held more species than the herb layer, being compositionally similar across habitats. Species richness was lower in forests and successional habitats compared to grasslands, with annual temperature range more important than mean annual temperature for determining richness. Climate and land‐use effects were generally less pronounced when plant community richness included seed bank species richness, while there was no clear effect of land use and climate on compositional similarity between the seed bank and the herb layer.Main conclusionsHigh seed bank diversity and compositional similarity between the herb layer and seed bank plant communities may provide a potentially important functional buffer against the impact of ongoing environmental changes on plant communities. This capacity could, however, be threatened by climate warming. Dormant life‐history stages can therefore be important sources of diversity in changing environments, potentially underpinning already observed time‐lags in plant community responses to global change. However, as soil seed banks themselves appear, albeit less, vulnerable to the same changes, their potential to buffer change can only be temporary, and major community shifts may still be expected.
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| 25. |
- Plue, Jan, et al.
(författare)
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European soil seed bank communities across a climate and land-cover gradient
- 2020
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Annan publikationabstract
- This is the data set used for the publication Buffering effects of soil seed banks on plant community composition in response to land use and climate, published in the journal Global Ecology and Biogeography.Aim.Climate and land use are key determinants of biodiversity, with past and ongoing changes posing serious threats to global ecosystems. Unlike most other organism groups, plant species can possess dormant life-history stages such as soil seed banks, which may help plant communities to resist or at least postpone the detrimental impact of global changes. This study investigates the potential for soil seed banks to achieve this.Location. EuropeTime period. 1978 – 2014Major taxa studied. Flowering plantsMethods.Using a space-for-time/warming approach, we study plant species richness and composition in the herb layer and the soil seed bank in 2796 community plots from 54 datasets in managed grasslands, forests and intermediate, successional habitats across a climate gradient.Results.Soil seed banks held more species than the herb layer, being compositionally similar across habitats. Species richness was lower in forests and successional habitats compared to grasslands, with annual temperature range more important than mean annual temperature for determining richness. Climate and land use effects were generally less pronounced when plant community richness included seed bank species richness, while there was no clear effect of land use and climate on compositional similarity between the seed bank and the herb layer.Main conclusions.High seed bank diversity and compositional similarity between the herb layer and seed bank plant communities may provide a potentially important functional buffer against the impact of ongoing environmental changes on plant communities. This capacity could, however, be threatened by climate warming. Dormant life-history stages can therefore be important sources of diversity in changing environments, potentially underpinning already observed time-lags in plant community responses to global change. However, as soil seed banks themselves appear, albeit less, vulnerable to the same changes, their potential to buffer change can only be temporary, and major community shifts may still be expected.MethodsThis dataset is a collection of 41 published and 5 unpublished data sets, consisting of 2796 plots with corresponding seed bank and herb layer community data. Sampling effort varied across data sets, but involved sampling of the soil and subsequent germination trials in a greenhouse to determine seed bank composition. Herb layer communities were determined by the identification of plants in relevés. Please consult the readme file and published paper for further details.Usage NotesPlease contact database or individual data set authors for further information and collaboration when using the data set or any of its component parts. Please also note that some of these data sets have already been published alongside their orginal papers. Finally, please cite data and datasets according to community standards.
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| 26. |
- Randich, S., et al.
(författare)
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The Gaia-ESO Public Spectroscopic Survey : Implementation, data products, open cluster survey, science, and legacy
- 2022
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Ingår i: Astronomy and Astrophysics. - : EDP SCIENCES S A. - 0004-6361 .- 1432-0746. ; 666
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Tidskriftsartikel (refereegranskat)abstract
- Context. In the last 15 years different ground-based spectroscopic surveys have been started (and completed) with the general aim of delivering stellar parameters and elemental abundances for large samples of Galactic stars, complementing Gaia astrometry. Among those surveys, the Gaia-ESO Public Spectroscopic Survey, the only one performed on a 8m class telescope, was designed to target 100 000 stars using FLAMES on the ESO VLT (both Giraffe and UVES spectrographs), covering all the Milky Way populations, with a special focus on open star clusters. Aims. This article provides an overview of the survey implementation (observations, data quality, analysis and its success, data products, and releases), of the open cluster survey, of the science results and potential, and of the survey legacy. A companion article reviews the overall survey motivation, strategy, Giraffe pipeline data reduction, organisation, and workflow. Methods. We made use of the information recorded and archived in the observing blocks; during the observing runs; in a number of relevant documents; in the spectra and master catalogue of spectra; in the parameters delivered by the analysis nodes and the working groups; in the final catalogue; and in the science papers. Based on these sources, we critically analyse and discuss the output and products of the Survey, including science highlights. We also determined the average metallicities of the open clusters observed as science targets and of a sample of clusters whose spectra were retrieved from the ESO archive. Results. The Gaia-ESO Survey has determined homogeneous good-quality radial velocities and stellar parameters for a large fraction of its more than 110 000 unique target stars. Elemental abundances were derived for up to 31 elements for targets observed with UVES. Lithium abundances are delivered for about 1/3 of the sample. The analysis and homogenisation strategies have proven to be successful; several science topics have been addressed by the Gaia-ESO consortium and the community, with many highlight results achieved. Conclusions. The final catalogue will be released through the ESO archive in the first half of 2022, including the complete set of advanced data products. In addition to these results, the Gaia-ESO Survey will leave a very important legacy, for several aspects and for many years to come.
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| 27. |
- Strickson, Sam, et al.
(författare)
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Oxidised IL-33 drives COPD epithelial pathogenesis via ST2-independent RAGE/EGFR signalling complex
- 2023
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Ingår i: European Respiratory Journal. - 0903-1936. ; 62:3
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Tidskriftsartikel (refereegranskat)abstract
- Background Epithelial damage, repair and remodelling are critical features of chronic airway diseases including chronic obstructive pulmonary disease (COPD). Interleukin (IL)-33 released from damaged airway epithelia causes inflammation via its receptor, serum stimulation-2 (ST2). Oxidation of IL-33 to a non-ST2-binding form (IL-33ox) is thought to limit its activity. We investigated whether IL-33ox has functional activities that are independent of ST2 in the airway epithelium. Methods In vitro epithelial damage assays and three-dimensional, air–liquid interface (ALI) cell culture models of healthy and COPD epithelia were used to elucidate the functional role of IL-33ox. Transcriptomic changes occurring in healthy ALI cultures treated with IL-33ox and COPD ALI cultures treated with an IL-33-neutralising antibody were assessed with bulk and single-cell RNA sequencing analysis. Results We demonstrate that IL-33ox forms a complex with receptor for advanced glycation end products (RAGE) and epidermal growth factor receptor (EGFR) expressed on airway epithelium. Activation of this alternative, ST2-independent pathway impaired epithelial wound closure and induced airway epithelial remodelling in vitro. IL-33ox increased the proportion of mucus-producing cells and reduced epithelial defence functions, mimicking pathogenic traits of COPD. Neutralisation of the IL-33ox pathway reversed these deleterious traits in COPD epithelia. Gene signatures defining the pathogenic effects of IL-33ox were enriched in airway epithelia from patients with severe COPD. Conclusions Our study reveals for the first time that IL-33, RAGE and EGFR act together in an ST2-independent pathway in the airway epithelium and govern abnormal epithelial remodelling and mucoobstructive features in COPD.
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| 28. |
- Ural, Ugur, et al.
(författare)
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An inefficient dwarf: chemical abundances and the evolution of the Ursa Minor dwarf spheroidal galaxy
- 2015
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Ingår i: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 1365-2966 .- 0035-8711. ; 449:1, s. 761-770
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Tidskriftsartikel (refereegranskat)abstract
- We present detailed chemical element abundance ratios of 17 elements with eight <= Z <= 60 in three metal-poor stars in the Ursa Minor dwarf spheroidal galaxy, which we combine with extant data from the literature to assess the predictions of a novel suite of galaxy chemical evolution models. The spectroscopic data were obtained with the Keck/High-Resolution Echelle Spectrograph instrument and revealed low metallicities of [Fe/H]= -2.12, -2.13 and -2.67 dex. While the most metal-poor star in our sample shows an overabundance of [Mn/Fe] and other Fe-peak elements, our overall findings are in agreement with previous studies of this galaxy: elevated values of the [alpha/Fe] ratios that are similar to, or only slightly lower than, the halo values but with SN Ia enrichment at very low metallicity, as well as an enhancement of the ratio of first to second peak neutron capture elements [Y/Ba] with decreasing metallicity. The chemical evolution models which were tailored to reproduce the metallicity distribution function of the dwarf spheroidal, indicate that Ursa Minor had an extended star formation which lasted nearly 5 Gyr with low efficiency and are able to explain the [Y/Ba] enhancement at low metallicity for the first time. In particular, we show that the present-day lack of gas is probably due to continuous loss of gas from the system, which we model as winds.
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| 29. |
- von Koch, Sacharias, et al.
(författare)
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Intracoronary Imaging of Proximal Coronary Artery Lesions – A Nationwide Lesion-Level Analysis From SCAAR
- 2023
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Ingår i: Journal of the Society for Cardiovascular Angiography & Interventions. - : Elsevier. - 2772-9303. ; 2:3
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Tidskriftsartikel (refereegranskat)abstract
- Background: Current evidence suggests that use of intracoronary imaging during percutaneous coronary intervention (PCI) of the left main coronary artery (LMCA) reduces mortality. However, there is a scarcity of data on the overall role of intracoronary imaging, particularly in other non-LMCA proximal coronary artery lesions. We aimed to investigate the association of use of intracoronary imaging on outcome in proximal lesions treated with PCI.Methods: The Swedish Coronary Angiography and Angioplasty Registry was used to identify all proximal coronary artery lesions treated with stent implantation between June 11, 2013, and January 16, 2021. Proximal coronary artery lesions (LMCA, proximal left anterior descending artery, left circumflex artery, and right coronary artery) assessed by intracoronary imaging before and/or after stent implantation were matched to control lesions treated based on angiography alone using propensity score matching. The primary end point was target lesion revascularization with PCI, and secondary end points included all-cause mortality and definite stent thrombosis within 3 years.Results: Among the 3623 matched pairs, intracoronary imaging was associated with significantly lower risk of target lesion revascularization, 3.7% vs 4.7%; hazard ratio (HR), 0.77; 95% CI, 0.61-0.97; P = .025, and all-cause mortality, 9.1% vs 12.8%; HR, 0.70; 95% CI, 0.61-0.81; P < .001, with no difference in definite stent thrombosis.Conclusions: The use of intracoronary imaging in proximal coronary artery lesions is associated with lower rates of repeat revascularization and better survival. The results appear to be primarily driven by improved outcome of LMCA lesions. These results reinforce the role of intracoronary imaging in assessing and treating proximal coronary lesions.
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| 30. |
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| 31. |
- Wigenstam, Elisabeth, et al.
(författare)
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Acute respiratory changes and pulmonary inflammation involving a pathway of TGF-beta 1 induction in a rat model of chlorine-induced lung injury
- 2016
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Ingår i: Toxicology and Applied Pharmacology. - : Elsevier BV. - 0041-008X .- 1096-0333. ; 309, s. 44-54
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Tidskriftsartikel (refereegranskat)abstract
- We investigated acute and delayed respiratory changes after inhalation exposure to chlorine (Cl-2) with the aim to understand the pathogenesis of the long-term sequelae of Cl-2-induced lung-injury. In a rat model of nose-only exposure we analyzed changes in airway hyperresponsiveness (AHR), inflammatory responses in airways, expression of pro-inflammatory markers and development of lung fibrosis during a time course from 5 h up to 90 days after a single inhalation of Cl-2. A single dose of dexamethasone (10 mg/Kg) was administered 1 h following Cl-2-exposure. A 15-min inhalation of 200 ppm Cl-2 was non-lethal in Sprague-Dawley rats. At 24 h post exposure, Cl-2-exposed rats displayed elevated numbers of leukocytes with an increase of neutrophils and eosinophils in bronchoalveolar lavage (BAL) and edema was shown both in lung tissue and the heart At 24 h, the inflammasome-associated cytokines IL-1 beta and IL-18 were detected in BAL Concomitant with the acute inflammation a significant AHR was detected. At the later time-points, a delayed inflammatory response was observed together with signs of lung fibrosis as indicated by increased pulmonary macrophages, elevated TGF-beta expression in BAL and collagen deposition around airways. Dexamethasone reduced the numbers of neutrophils in BAL at 24 h but did not influence the AHR. Inhalation of Cl-2 in rats leads to acute respiratory and cardiac changes as well as pulmonary inflammation involving induction of TGF-beta 1. The acute inflammatory response was followed by sustained macrophage response and lack of tissue repair. It was also found that pathways apart from the acute inflammatory response contribute to the Cl(2-)induced respiratory dysfunction.
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| 32. |
- Wigenstam, Elisabeth, 1980-, et al.
(författare)
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Corticosteroid treatment inhibits airway hyperreactivity and lung injury in a murine model of chemical-induced airway inflammation
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Context: Exposure to toxic alkylating mustard agents causes both acute and long-term effects to the lungs as indicated by increased number of inflammatory cells in airways, lung edema and lung tissue fibrosis. We have previously demonstrated that treatment with the corticosteroid dexamethasone 1 hr after lung exposure to the alkylating mustard melphalan, protect mice from acute and sub-acute inflammatory responses, as well as from lung fibrosis. Objective: In order to address the importance of early anti-inflammatory treatment, we investigated the therapeutic effect of dexamethasone administered 1, 2 or 6 hrs following exposure to melphalan. Methods: Female C57BL/6 mice were via intratracheal instillation exposed to the nitrogen mustard analogue melphalan and treated i.p. with dexamethasone 1, 2 or 6 hours after exposure. Twenty hours or 14 days post exposure mice were subjected to analysis of respiratory mechanics where the effects of incremental doses of methacholine on central and peripheral lung components were measured. We also determined the amount of neutrophils and lymphocytes in the bronchoalveolar lavage fluid and measured the amount of collagen content in the lungs. Results: Melphalan exposure exerted a significant effect on both central and peripheral respiratory function. Dexamethasone given one hour post exposure protected the lung against the damaging effects of melphalan. Collagen deposition 14 days after exposure was decreased with dexamethasone treatment. Conclusion: Early dexamethasone treatment (within one hour after exposure) is important in order to reduce the airway reactivity and inflammation caused by toxic alkylating mustards such as melphalan.
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| 33. |
- Wigenstam, Elisabeth, et al.
(författare)
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Corticosteroid treatment inhibits airway hyperresponsiveness and lung injury in a murine model of chemical-induced airway inflammation
- 2012
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Ingår i: Toxicology. - : Elsevier BV. - 0300-483X .- 1879-3185. ; 301:1-3, s. 66-71
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Tidskriftsartikel (refereegranskat)abstract
- Context: Exposure to toxic alkylating mustard agents causes both acute and long-term effects to the lungs as indicated by increased number of inflammatory cells in airways, lung edema and lung tissue fibrosis. We have previously demonstrated that treatment with the corticosteroid dexamethasone 1 h after lung exposure to the nitrogen mustard analog melphalan protects mice from acute and sub-acute inflammatory responses, as well as from lung tissue fibrosis. Objective: In order to address the importance of early anti-inflammatory treatment, we investigated the therapeutic effect of dexamethasone administered 1, 2 or 6 h following exposure to melphalan. Methods: C57BL/6 mice were exposed to melphalan and treated with dexamethasone 1,2 or 6 h after exposure. Twenty hours or 14 days post exposure mice were subjected to analysis of respiratory mechanics where the effects of incremental doses of methacholine on central and peripheral lung components were measured. We also determined the amount of inflammatory cells in the bronchoalveolar lavage fluid and measured the amount of collagen content in the lungs. Results: Melphalan exposure increased airway hyperresponsiveness in both central and peripheral airways and induced an airway inflammation dominated by infiltration of macrophages and neutrophils. Dexamethasone given 1 h after exposure to melphalan provided better protection against airway inflammation than administration 2 or 6 h after exposure. Collagen deposition 14 days after exposure was decreased due to dexamethasone treatment. Conclusion: Early treatment with dexamethasone is important in order to reduce the airway hyperresponsiveness and inflammation caused by toxic alkylating mustards such as melphalan. (c) 2012 Elsevier Ireland Ltd. All rights reserved.
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| 34. |
- Wigenstam, Elisabeth, et al.
(författare)
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N-acetyl cysteine improves the effects of corticosteroids in a mouse model of chlorine-induced acute lung injury
- 2015
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Ingår i: Toxicology. - : Elsevier BV. - 0300-483X .- 1879-3185. ; 328, s. 40-47
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Tidskriftsartikel (refereegranskat)abstract
- Chlorine (Cl-2) causes tissue damage and a neutrophilic inflammatory response in the airways manifested by pronounced airway hyperreactivity (AHR). The importance of early anti-inflammatory treatment has previously been addressed. In the previous study, both high-dose and low-dose of dexamethasone (DEX) decreased the risk of developing delayed effects, such as persistent lung injuries, while only high-dose treatment could significantly counteract acute-phase effects. One aim of this study was to evaluate whether a low-dose of DEX in combination with the antioxidant N-acetyl cysteine (NAC) and if different treatments (Triptolide, Reparixin and Rolipram) administered 1 h after Cl-2-exposure could improve protection against acute lung injury in Cl-2-exposed mice. BALB/c mice were exposed to 300 ppm Cl-2 during 15 min. Assessment of AHR and inflammatory cells in bronchoalveolar lavage was analyzed 24 h post exposure. Neither of DEX nor NAC reduced the AHR and displayed only minor effects on inflammatory cell influx when given as separate treatments. When given in combination, a protective effect on AHR and a significant reduction in inflammatory cells (neutrophils) was observed. Neither of triptolide, Reparixin nor Rolipram had an effect on AHR but Triptolide had major effect on the inflammatory cell influx. Treatments did not reduce the concentration of either fibrinogen or plasminogen activator inhibitor-1 in serum, thereby supporting the theory that the inflammatory response is not solely limited to the lung. These results provide a foundation for future studies aimed at identifying new concepts for treatment of chemical-induced lung injury. Studies addressing combination of anti-inflammatory and antioxidant treatment are highly motivated.
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