| 1. |
- Adam, J, et al.
(författare)
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Measurement of pion, kaon and proton production in proton-proton collisions at [Formula: see text] TeV.
- 2015
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 75:5
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Tidskriftsartikel (refereegranskat)abstract
- The measurement of primary [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] production at mid-rapidity ([Formula: see text] 0.5) in proton-proton collisions at [Formula: see text][Formula: see text] 7 TeV performed with a large ion collider experiment at the large hadron collider (LHC) is reported. Particle identification is performed using the specific ionisation energy-loss and time-of-flight information, the ring-imaging Cherenkov technique and the kink-topology identification of weak decays of charged kaons. Transverse momentum spectra are measured from 0.1 up to 3 GeV/[Formula: see text] for pions, from 0.2 up to 6 GeV/[Formula: see text] for kaons and from 0.3 up to 6 GeV/[Formula: see text] for protons. The measured spectra and particle ratios are compared with quantum chromodynamics-inspired models, tuned to reproduce also the earlier measurements performed at the LHC. Furthermore, the integrated particle yields and ratios as well as the average transverse momenta are compared with results at lower collision energies.
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| 2. |
- Abelev, B, et al.
(författare)
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Directed Flow of Charged Particles at Midrapidity Relative to the Spectator Plane in Pb-Pb Collisions at sqrt[s_{NN}]=2.76 TeV.
- 2013
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Ingår i: Physical Review Letters. - 1079-7114. ; 111:23
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Tidskriftsartikel (refereegranskat)abstract
- The directed flow of charged particles at midrapidity is measured in Pb-Pb collisions at sqrt[s_{NN}]=2.76 TeV relative to the collision symmetry plane defined by the spectator nucleons. A negative slope of the rapidity-odd directed flow component with approximately 3 times smaller magnitude than found at the highest RHIC energy is observed. This suggests a smaller longitudinal tilt of the initial system and disfavors the strong fireball rotation predicted for the LHC energies. The rapidity-even directed flow component is measured for the first time with spectators and found to be independent of pseudorapidity with a sign change at transverse momenta p_{T} between 1.2 and 1.7 GeV/c. Combined with the observation of a vanishing rapidity-even p_{T} shift along the spectator deflection this is strong evidence for dipolelike initial density fluctuations in the overlap zone of the nuclei. Similar trends in the rapidity-even directed flow and the estimate from two-particle correlations at midrapidity, which is larger by about a factor of 40, indicate a weak correlation between fluctuating participant and spectator symmetry planes. These observations open new possibilities for investigation of the initial conditions in heavy-ion collisions with spectator nucleons.
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| 3. |
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| 4. |
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| 5. |
- Abelev, B, et al.
(författare)
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K_{S}^{0} and Λ Production in Pb-Pb Collisions at sqrt[s_{NN}]=2.76 TeV.
- 2013
-
Ingår i: Physical Review Letters. - 1079-7114. ; 111:22
-
Tidskriftsartikel (refereegranskat)abstract
- The ALICE measurement of K_{S}^{0} and Λ production at midrapidity in Pb-Pb collisions at sqrt[s_{NN}]=2.76 TeV is presented. The transverse momentum (p_{T}) spectra are shown for several collision centrality intervals and in the p_{T} range from 0.4 GeV/c (0.6 GeV/c for Λ) to 12 GeV/c. The p_{T} dependence of the Λ/K_{S}^{0} ratios exhibits maxima in the vicinity of 3 GeV/c, and the positions of the maxima shift towards higher p_{T} with increasing collision centrality. The magnitude of these maxima increases by almost a factor of three between most peripheral and most central Pb-Pb collisions. This baryon excess at intermediate p_{T} is not observed in pp interactions at sqrt[s]=0.9 TeV and at sqrt[s]=7 TeV. Qualitatively, the baryon enhancement in heavy-ion collisions is expected from radial flow. However, the measured p_{T} spectra above 2 GeV/c progressively decouple from hydrodynamical-model calculations. For higher values of p_{T}, models that incorporate the influence of the medium on the fragmentation and hadronization processes describe qualitatively the p_{T} dependence of the Λ/K_{S}^{0} ratio.
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| 6. |
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| 7. |
- Böhm, M., et al.
(författare)
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The conservation status of the world’s freshwater molluscs
- 2021
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Ingår i: Hydrobiologia. - : Springer Science and Business Media LLC. - 0018-8158 .- 1573-5117. ; 848, s. 3231-3254
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Tidskriftsartikel (refereegranskat)abstract
- With the biodiversity crisis continuing unchecked, we need to establish levels and drivers of extinction risk, and reassessments over time, to effectively allocate conservation resources and track progress towards global conservation targets. Given that threat appears particularly high in freshwaters, we assessed the extinction risk of 1428 randomly selected freshwater molluscs using the IUCN Red List Categories and Criteria, as part of the Sampled Red List Index project. We show that close to one-third of species in our sample are estimated to be threatened with extinction, with highest levels of threat in the Nearctic, Palearctic and Australasia and among gastropods. Threat levels were higher in lotic than lentic systems. Pollution (chemical and physical) and the modification of natural systems (e.g. through damming and water abstraction) were the most frequently reported threats to freshwater molluscs, with some regional variation. Given that we found little spatial congruence between species richness patterns of freshwater molluscs and other freshwater taxa, apart from crayfish, new additional conservation priority areas emerged from our study. We discuss the implications of our findings for freshwater mollusc conservation, the adequacy of a sampled approach and important next steps to estimate trends in freshwater mollusc extinction risk over time. © 2020, Springer Nature Switzerland AG.
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| 8. |
- Jansen, Willemijn J, et al.
(författare)
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Association of Cerebral Amyloid-β Aggregation With Cognitive Functioning in Persons Without Dementia.
- 2018
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Ingår i: JAMA psychiatry. - : American Medical Association (AMA). - 2168-6238 .- 2168-622X. ; 75:1, s. 84-95
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Tidskriftsartikel (refereegranskat)abstract
- Cerebral amyloid-β aggregation is an early event in Alzheimer disease (AD). Understanding the association between amyloid aggregation and cognitive manifestation in persons without dementia is important for a better understanding of the course of AD and for the design of prevention trials.To investigate whether amyloid-β aggregation is associated with cognitive functioning in persons without dementia.This cross-sectional study included 2908 participants with normal cognition and 4133 with mild cognitive impairment (MCI) from 53 studies in the multicenter Amyloid Biomarker Study. Normal cognition was defined as having no cognitive concerns for which medical help was sought and scores within the normal range on cognitive tests. Mild cognitive impairment was diagnosed according to published criteria. Study inclusion began in 2013 and is ongoing. Data analysis was performed in January 2017.Global cognitive performance as assessed by the Mini-Mental State Examination (MMSE) and episodic memory performance as assessed by a verbal word learning test. Amyloid aggregation was measured with positron emission tomography or cerebrospinal fluid biomarkers and dichotomized as negative (normal) or positive (abnormal) according to study-specific cutoffs. Generalized estimating equations were used to examine the association between amyloid aggregation and low cognitive scores (MMSE score ≤27 or memory z score≤-1.28) and to assess whether this association was moderated by age, sex, educational level, or apolipoprotein E genotype.Among 2908 persons with normal cognition (mean [SD] age, 67.4 [12.8] years), amyloid positivity was associated with low memory scores after age 70 years (mean difference in amyloid positive vs negative, 4% [95% CI, 0%-7%] at 72 years and 21% [95% CI, 10%-33%] at 90 years) but was not associated with low MMSE scores (mean difference, 3% [95% CI, -1% to 6%], P=.16). Among 4133 patients with MCI (mean [SD] age, 70.2 [8.5] years), amyloid positivity was associated with low memory (mean difference, 16% [95% CI, 12%-20%], P<.001) and low MMSE (mean difference, 14% [95% CI, 12%-17%], P<.001) scores, and this association decreased with age. Low cognitive scores had limited utility for screening of amyloid positivity in persons with normal cognition and those with MCI. In persons with normal cognition, the age-related increase in low memory score paralleled the age-related increase in amyloid positivity with an intervening period of 10 to 15 years.Although low memory scores are an early marker of amyloid positivity, their value as a screening measure for early AD among persons without dementia is limited.
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| 9. |
- Jansen, Willemijn J, et al.
(författare)
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Prevalence of cerebral amyloid pathology in persons without dementia: a meta-analysis.
- 2015
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Ingår i: JAMA. - : American Medical Association (AMA). - 1538-3598 .- 0098-7484. ; 313:19, s. 1924-38
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Tidskriftsartikel (refereegranskat)abstract
- Cerebral amyloid-β aggregation is an early pathological event in Alzheimer disease (AD), starting decades before dementia onset. Estimates of the prevalence of amyloid pathology in persons without dementia are needed to understand the development of AD and to design prevention studies.
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| 10. |
- Sachdev, P. S., et al.
(författare)
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STROKOG (stroke and cognition consortium): An international consortium to examine the epidemiology, diagnosis, and treatment of neurocognitive disorders in relation to cerebrovascular disease
- 2017
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Ingår i: Alzheimer's & Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 7, s. 11-23
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Tidskriftsartikel (refereegranskat)abstract
- Introduction The Stroke and Cognition consortium (STROKOG) aims to facilitate a better understanding of the determinants of vascular contributions to cognitive disorders and help improve the diagnosis and treatment of vascular cognitive disorders (VCD). Methods Longitudinal studies with ≥75 participants who had suffered or were at risk of stroke or TIA and which evaluated cognitive function were invited to join STROKOG. The consortium will facilitate projects investigating rates and patterns of cognitive decline, risk factors for VCD, and biomarkers of vascular dementia. Results Currently, STROKOG includes 25 (21 published) studies, with 12,092 participants from five continents. The duration of follow-up ranges from 3months to 21years. Discussion Although data harmonization will be a key challenge, STROKOG is in a unique position to reuse and combine international cohort data and fully explore patient level characteristics and outcomes. STROKOG could potentially transform our understanding of VCD and have a worldwide impact on promoting better vascular cognitive outcomes. © 2016 The Authors
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| 11. |
- Deans, Andrew R, et al.
(författare)
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Finding Our Way through Phenotypes.
- 2015
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Ingår i: PLoS Biology. - : Public Library of Science (PLoS). - 1545-7885. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Despite a large and multifaceted effort to understand the vast landscape of phenotypic data, their current form inhibits productive data analysis. The lack of a community-wide, consensus-based, human- and machine-interpretable language for describing phenotypes and their genomic and environmental contexts is perhaps the most pressing scientific bottleneck to integration across many key fields in biology, including genomics, systems biology, development, medicine, evolution, ecology, and systematics. Here we survey the current phenomics landscape, including data resources and handling, and the progress that has been made to accurately capture relevant data descriptions for phenotypes. We present an example of the kind of integration across domains that computable phenotypes would enable, and we call upon the broader biology community, publishers, and relevant funding agencies to support efforts to surmount today's data barriers and facilitate analytical reproducibility.
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| 12. |
- Richter, B., et al.
(författare)
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New results in the search for narrow states in the p system below threshold
- 1983
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 126:3-4, s. 284-288
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Tidskriftsartikel (refereegranskat)abstract
- The γ-ray spectrum after p annihilation at rest was measured in two independent high-statistics runs. Both spectra show narrow peaks, corresponding to masses of 1210, 1638, 1694 and 1771 MeV.
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| 13. |
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| 14. |
- Köhler, Th., et al.
(författare)
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Precision measurement of strong interaction isotope effects in antiprotonic 16O, 17O, and 18O atoms
- 1986
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 176:3-4, s. 327-333
-
Tidskriftsartikel (refereegranskat)abstract
- The strong-interaction effects in antiprotonic 16O, 17O, and 18O atoms were measured at the CERN antiproton facility, LEAR. The shifts ε{lunate} and the widths Γ of the 3d level were determined to be -112±20 eV (16O), -140±46 eV (17O), -195±20 eV (18O), and 495±45 eV (16O), 540±150 (17O), 640±40 eV (18O), respectively. © 1986.
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| 15. |
- Reimer, Paula J., et al.
(författare)
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The IntCal20 Northern Hemisphere Radiocarbon Age Calibration Curve (0-55 cal kBP)
- 2020
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Ingår i: Radiocarbon. - 0033-8222. ; 62:4, s. 725-757
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Tidskriftsartikel (refereegranskat)abstract
- Radiocarbon (C) ages cannot provide absolutely dated chronologies for archaeological or paleoenvironmental studies directly but must be converted to calendar age equivalents using a calibration curve compensating for fluctuations in atmospheric C concentration. Although calibration curves are constructed from independently dated archives, they invariably require revision as new data become available and our understanding of the Earth system improves. In this volume the international C calibration curves for both the Northern and Southern Hemispheres, as well as for the ocean surface layer, have been updated to include a wealth of new data and extended to 55,000 cal BP. Based on tree rings, IntCal20 now extends as a fully atmospheric record to ca. 13,900 cal BP. For the older part of the timescale, IntCal20 comprises statistically integrated evidence from floating tree-ring chronologies, lacustrine and marine sediments, speleothems, and corals. We utilized improved evaluation of the timescales and location variable C offsets from the atmosphere (reservoir age, dead carbon fraction) for each dataset. New statistical methods have refined the structure of the calibration curves while maintaining a robust treatment of uncertainties in the C ages, the calendar ages and other corrections. The inclusion of modeled marine reservoir ages derived from a three-dimensional ocean circulation model has allowed us to apply more appropriate reservoir corrections to the marine C data rather than the previous use of constant regional offsets from the atmosphere. Here we provide an overview of the new and revised datasets and the associated methods used for the construction of the IntCal20 curve and explore potential regional offsets for tree-ring data. We discuss the main differences with respect to the previous calibration curve, IntCal13, and some of the implications for archaeology and geosciences ranging from the recent past to the time of the extinction of the Neanderthals.
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| 16. |
- Arkhammar, P., et al.
(författare)
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Protein kinase C modulates the insulin secretory process by maintaining a proper function of the beta-cell voltage-activated Ca2+ channels
- 1994
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Ingår i: Journal of Biological Chemistry. - : Baishideng Publishers. - 0021-9258 .- 1083-351X. ; 269:4, s. 2743-2749
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Tidskriftsartikel (refereegranskat)abstract
- In the present study an attempt was made to further elucidate the molecular mechanisms whereby protein kinase C (PKC) modulates the beta-cell stimulus-secretion coupling. Regulation of Ca2+ channel activity, [Ca2+]i, and insulin release were investigated in both normal pancreatic mouse beta-cells and in similar beta-cells deprived of PKC activity. [Ca2+]i was measured with the intracellular fluorescent Ca2+ indicator fura-2 and the Ca2+ channel activity was estimated by the whole cell configuration of the patch-clamp technique. To reveal the various isoenzymes of PKC present in the mouse beta-cell, proteins were separated by one-dimensional gel electrophoresis and Western blotting was performed. The production of inositol phosphates was measured by ion-exchange chromatography and insulin release was measured radioimmunologically. Acute stimulation with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate resulted in suppression of both the carbamylcholine-induced increase in [Ca2+]i and production of inositol 1,4,5-trisphosphate. Under these conditions the increase in [Ca2+]i in response to glucose was similar to that found in control cells. When beta-cells were deprived of PKC, by exposure to 200 nM 12-O-tetradecanoylphorbol-13-acetate for 24-48 h, there was an enhanced response to carbamylcholine. This response constituted increases in both the [Ca2+]i signal and production of inositol 1,4,5-trisphosphate. Interestingly, cells with down-regulated PKC activity responded more slowly to glucose stimulation, when comparing the initial increase in [Ca2+]i, than control cells. On the other hand, the maximal increase in [Ca2+]i was similar whether or not PKC was present. Moreover, PKC down-regulated cells exhibited a significant reduction of maximal whole cell Ca2+ currents, a finding that may explain the altered kinetics with regard to the [Ca2+]i increase in response to the sugar. Both the alpha and beta 1 forms of the PKC isoenzymes were present in the mouse beta-cell and were also subjected to PKC down-regulation. Hence, either of these isoenzymes or both may be involved in the modulation of phospholipase C and Ca2+ channel activity. Since insulin release under physiological conditions is critically dependent on Ca(2+)-influx through the voltage-gated L-type Ca2+ channels, the kinetics of hormone release was expected to demonstrate a similar delay as that of the [Ca2+]i increase. Although not as pronounced, such a delay was indeed also observed in the onset of insulin release. There was, however, no effect on the total amounts of hormone released. There was,h owever, no effect on thet otal amounts of hormone released. The present study con- firms that PKC has multiple roles and thereby interacta at different sites in the complex series of events consti- tuting the #?-cell signal-transduction pathway. It is sug- gested that PKC may be tonically active and effective in the maintenance of the phosphorylation state of the voltage-gated L-type Ca2+ channel, enabling an appro- priate function of this channel in the insulin secretory process.
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| 17. |
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| 18. |
- Haid, Sibylle, et al.
(författare)
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Repurposing screen identifies novel candidates for broad-spectrum coronavirus antivirals and druggable host targets
- 2024
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Ingår i: Antimicrobial Agents and Chemotherapy. - : American Society for Microbiology. - 0066-4804 .- 1098-6596. ; 68:3
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Tidskriftsartikel (refereegranskat)abstract
- Libraries composed of licensed drugs represent a vast repertoire of molecules modulating physiological processes in humans, providing unique opportunities for the discovery of host-targeting antivirals. We screened the Repurposing, Focused Rescue, and Accelerated Medchem (ReFRAME) repurposing library with approximately 12,000 molecules for broad-spectrum coronavirus antivirals and discovered 134 compounds inhibiting an alphacoronavirus and mapping to 58 molecular target categories. Dominant targets included the 5-hydroxytryptamine receptor, the dopamine receptor, and cyclin-dependent kinases. Gene knock-out of the drugs’ host targets including cathepsin B and L (CTSB/L; VBY-825), the aryl hydrocarbon receptor (AHR; Phortress), the farnesyl-diphosphate farnesyltransferase 1 (FDFT1; P-3622), and the kelch-like ECH-associated protein 1 (KEAP1; Omaveloxolone), significantly modulated HCoV-229E infection, providing evidence that these compounds inhibited the virus through acting on their respective host targets. Counter-screening of all 134 primary compound candidates with SARS-CoV-2 and validation in primary cells identified Phortress, an AHR activating ligand, P-3622-targeting FDFT1, and Omaveloxolone, which activates the NFE2-like bZIP transcription factor 2 (NFE2L2) by liberating it from its endogenous inhibitor KEAP1, as antiviral candidates for both an Alpha- and a Betacoronavirus. This study provides an overview of HCoV-229E repurposing candidates and reveals novel potentially druggable viral host dependency factors hijacked by diverse coronaviruses.
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| 19. |
- Hilt, Sabine, et al.
(författare)
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Response of submerged macrophyte communities to external and internal restoration measures in north temperate shallow lakes
- 2018
-
Ingår i: Frontiers in Plant Science. - : Frontiers Media SA. - 1664-462X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Submerged macrophytes play a key role in north temperate shallow lakes by stabilizing clear-water conditions. Eutrophication has resulted in macrophyte loss and shifts to turbid conditions in many lakes. Considerable efforts have been devoted to shallow lake restoration in many countries, but long-term success depends on a stable recovery of submerged macrophytes. However, recovery patterns vary widely and remain to be fully understood. We hypothesize that reduced external nutrient loading leads to an intermediate recovery state with clear spring and turbid summer conditions similar to the pattern described for eutrophication. In contrast, lake internal restoration measures can result in transient clear-water conditions both in spring and summer and reversals to turbid conditions. Furthermore, we hypothesize that these contrasting restoration measures result in different macrophyte species composition, with added implications for seasonal dynamics due to differences in plant traits. To test these hypotheses, we analyzed data on water quality and submerged macrophytes from 49 north temperate shallow lakes that were in a turbid state and subjected to restoration measures. To study the dynamics of macrophytes during nutrient load reduction, we adapted the ecosystem model PCLake. Our survey and model simulations revealed the existence of an intermediate recovery state upon reduced external nutrient loading, characterized by spring clear-water phases and turbid summers, whereas internal lake restoration measures often resulted in clear-water conditions in spring and summer with returns to turbid conditions after some years. External and internal lake restoration measures resulted in different macrophyte communities. The intermediate recovery state following reduced nutrient loading is characterized by a few macrophyte species (mainly pondweeds) that can resist wave action allowing survival in shallowareas, germinate early in spring, have energy-rich vegetative propagules facilitating rapid initial growth and that can complete their life cycle by early summer. Later in the growing season these plants are, according to our simulations, outcompeted by periphyton, leading to late-summer phytoplankton blooms. Internal lake restoration measures often coincide with a rapid but transient colonization by hornworts, waterweeds or charophytes. Stable clear-water conditions and a diverse macrophyte flora only occurred decades after external nutrient load reduction or when measures were combined.
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| 20. |
- Köhler, Christian, et al.
(författare)
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Dynamic allosteric communication pathway directing differential activation of the glucocorticoid receptor
- 2020
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Ingår i: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 6:29
-
Tidskriftsartikel (refereegranskat)abstract
- Allosteric communication within proteins is a hallmark of biochemical signaling, but the dynamic transmission pathways remain poorly characterized. We combined NMR spectroscopy and surface plasmon resonance to reveal these pathways and quantify their energetics in the glucocorticoid receptor, a transcriptional regulator controlling development, metabolism, and immune response. Our results delineate a dynamic communication network of residues linking the ligand-binding pocket to the activation function-2 interface, where helix 12, a switch for transcriptional activation, exhibits ligand- and coregulator-dependent dynamics coupled to graded activation. The allosteric free energy responds to variations in ligand structure: subtle changes gradually tune allostery while preserving the transmission pathway, whereas substitution of the entire pharmacophore leads to divergent allosteric control by apparently rewiring the communication network. Our results provide key insights that should aid in the design of mechanistically differentiated ligands.
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| 21. |
- Köhler, Elof, 1980, et al.
(författare)
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Proof of concept thermoelectric energy harvester powering wireless sensor on gas turbine
- 2016
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Ingår i: EVI-GTI and PIWG Joint Conference on Gas Turbine Instrumentation, Berlin, Germany, 27-29 September 2016. - : Institution of Engineering and Technology. ; 2016:CP693
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Konferensbidrag (refereegranskat)abstract
- The thermoelectric energy harvester went from simulations to synthesis of materials and fabrication of test prototypes. We also made measurements on a 1-couple module which did show that the technology is feasible, however very demanding and difficult to build at current state. We also showed with commercial modules that the high temperature energy harvester could power a Wi-Fi at current size of 1 cm2 and 0.4 g if a durable prototype with 7 couples could be manufactured successfully.
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| 22. |
- Moing, A, et al.
(författare)
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Quantitative metabolic pro. ling by 1-dimensional H-1-NMR analyses : application to plant genetics and functional genomics
- 2004
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Ingår i: Functional Plant Biology. - : CSIRO PUBLISHING. - 1445-4408 .- 1445-4416. ; 31:9, s. 889-902
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Tidskriftsartikel (refereegranskat)abstract
- Metabolic profiling by 1-dimensional (1-D) H-1-nuclear magnetic resonance (NMR) was tested for absolute quanti. cation of soluble sugars, organic acids, amino acids and some secondary metabolites in fruit, roots and leaves. The metabolite responsible for each peak of the H-1-NMR spectra was identified from spectra of pure compounds. Peak identity was confirmed by the addition of a small amount of commercially-available pure substance. H-1-NMR spectra acquisition was automated. H-1-NMR absolute quantification was performed with a synthesised electronic reference signal and validated by comparison with enzymatic or HPLC analyses; the correlation coefficients between H-1-NMR data and enzymatic or HPLC data were highly significant. Depending on the species and tissues, 14 - 17 metabolites could be quantified with 15 - 25 min acquisition time. The detection limit was approximately 1 - 9 mug in the NMR tube, depending on the compound. Quantitative data were used for ( 1) a genetic study of strawberry fruit quality, ( 2) a functional study of tomato transformants overexpressing hexokinase and ( 3) a study of Arabidopsis phosphoenolpyruvate carboxylase transformants with several lines showing decreased activity of the enzyme. Biochemical phenotyping of the fruits of a strawberry offspring allowed the detection of quantitative trait loci (QTL) controlling fruit quality. Comparison of the roots of wild types and hexokinase tomato transformants using principal component analysis of metabolic profiles revealed that environmental factors, i.e. culture conditions, can significantly modify the metabolic status of plants and thus hide or emphasise the expression of a given genetic background. The decrease in phosphoenolpyruvate carboxylase activity ( up to 75%) in Arabidopsis transformants impacted on the metabolic profiles without compromising plant growth, thus supporting the idea that the enzyme has a low influence on the carbon flux through the anaplerotic pathway.
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| 23. |
- Moritz, J., et al.
(författare)
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Functional integration approaches via laser powder bed processing
- 2019
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Ingår i: Journal of laser applications. - : Laser Institute of America. - 1042-346X .- 1938-1387. ; 31:2
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Tidskriftsartikel (refereegranskat)abstract
- Additive manufacturing design rules are different from those of conventional fabrication techniques. These allow geometries that would not be possible to achieve otherwise. One example of application is the integration of functional parts as part of the manufacturing process. Conceivable applications range from mechanical functions like integration of moving parts or thermodynamic functions, for example, cooling channels or incorporation of electric circuits for electrical functionalization [J. Glasschroeder, E. Prager, and M. F. Zaeh, Rapid Prototyping J. 21, 207–215 (2015)]. Nevertheless, the potential of functional integration using powder-bed processes is far from being exhausted. The present approach addresses the generation of inner cavities and internal structures of titanium-based parts or components by the use of selective laser melting. This paper focusses on the investigation of voids and cavities regarding their capabilities to add new functions to the material. To this end, comprehensive characterization is performed using destructive as well as nondestructive testing methods. These include 3D scanning, computed tomography, and surface roughness measurements as well as microscopic analysis. Voids and cavities were filled with different thermoplastic materials, followed by the qualitative assessment of the mold filling and resulting material properties. Finally, applications are derived and evaluated with respect to the field of lightweight design or damping structures.
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| 24. |
- Moroder, M., et al.
(författare)
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Stable bipolarons in open quantum systems
- 2023
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Ingår i: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 107:21
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Tidskriftsartikel (refereegranskat)abstract
- Recent advances in numerical methods significantly pushed forward the understanding of electrons coupled to quantized lattice vibrations. At this stage, it becomes increasingly important to also account for the effects of physically inevitable environments. Here, we combine state-of-the-art tensor-network and quantum trajectories methods in order to study the impact of dissipation on realistic condensed matter models including highly excited phononic modes. In particular, we study the transport properties of the Hubbard-Holstein Hamiltonian that models a large class of materials characterized by strong electron-phonon coupling, in contact with a dissipative environment. We combine the non-Markovian hierarchy of pure states method and the Markovian quantum jumps method with the newly introduced projected purified density-matrix renormalization group, creating powerful tensor-network methods for dissipative quantum many-body systems. Investigating their numerical properties, we find a significant speedup up to a factor approximate to 30 compared to conventional tensor-network techniques. We apply these methods to study dissipative quenches, aiming for an in-depth understanding of the formation, stability, and quasiparticle properties of bipolarons. Surprisingly, our results show that in the metallic phase dissipation localizes the bipolarons, which is reminiscent of an indirect quantum Zeno effect. However, the bipolaronic binding energy remains mainly unaffected, even in the presence of strong dissipation, exhibiting remarkable bipolaron stability. These findings shed light on the problem of designing real materials exhibiting phonon-mediated high-TC superconductivity.
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| 25. |
- Peters, Ruth, et al.
(författare)
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An investigation of antihypertensive class, dementia, and cognitive decline: A meta-analysis.
- 2020
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Ingår i: Neurology. - 1526-632X. ; 94:3
-
Tidskriftsartikel (refereegranskat)abstract
- High blood pressure is one of the main modifiable risk factors for dementia. However, there is conflicting evidence regarding the best antihypertensive class for optimizing cognition. Our objective was to determine whether any particular antihypertensive class was associated with a reduced risk of cognitive decline or dementia using comprehensive meta-analysis including reanalysis of original participant data.To identify suitable studies, MEDLINE, Embase, and PsycINFO and preexisting study consortia were searched from inception to December 2017. Authors of prospective longitudinal human studies or trials of antihypertensives were contacted for data sharing and collaboration. Outcome measures were incident dementia or incident cognitive decline (classified using the reliable change index method). Data were separated into mid and late-life (>65 years) and each antihypertensive class was compared to no treatment and to treatment with other antihypertensives. Meta-analysis was used to synthesize data.Over 50,000 participants from 27 studies were included. Among those aged >65 years, with the exception of diuretics, we found no relationship by class with incident cognitive decline or dementia. Diuretic use was suggestive of benefit in some analyses but results were not consistent across follow-up time, comparator group, and outcome. Limited data precluded meaningful analyses in those ≤65 years of age.Our findings, drawn from the current evidence base, support clinical freedom in the selection of antihypertensive regimens to achieve blood pressure goals.The review was registered with the international prospective register of systematic reviews (PROSPERO), registration number CRD42016045454.
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| 26. |
- Shi, Lei, 1981, et al.
(författare)
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Connection between protein-tyrosine kinase inhibition and coping with oxidative stress in Bacillus subtilis
- 2024
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - 0027-8424 .- 1091-6490. ; 121:25
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Tidskriftsartikel (refereegranskat)abstract
- In bacteria, attenuation of protein-tyrosine phosphorylation occurs during oxidative stress. The main described mechanism behind this effect is the H2O2-triggered conversion of bacterial phospho-tyrosines to protein-bound 3,4-dihydroxyphenylalanine. This disrupts the bacterial tyrosine phosphorylation-based signaling network, which alters the bacterial polysaccharide biosynthesis. Herein, we report an alternative mechanism, in which oxidative stress leads to a direct inhibition of bacterial protein-tyrosine kinases (BY-kinases). We show that DefA, a minor peptide deformylase, inhibits the activity of BY-kinase PtkA when Bacillus subtilis is exposed to oxidative stress. High levels of PtkA activity are known to destabilize B. subtilis pellicle formation, which leads to higher sensitivity to oxidative stress. Interaction with DefA inhibits both PtkA autophosphorylation and phosphorylation of its substrate Ugd, which is involved in exopolysaccharide formation. Inactivation of defA drastically reduces the capacity of B. subtilis to cope with oxidative stress, but it does not affect the major oxidative stress regulons PerR, OhrR, and Spx, indicating that PtkA inhibition is the main pathway for DefA involvement in this stress response. Structural analysis identified DefA residues Asn95, Tyr150, and Glu152 as essential for interaction with PtkA. Inhibition of PtkA depends also on the presence of a C-terminal α-helix of DefA, which resembles PtkA-interacting motifs from known PtkA activators, TkmA, SalA, and MinD. Loss of either the key interacting residues or the inhibitory helix of DefA abolishes inhibition of PtkA in vitro and impairs postoxidative stress recovery in vivo, confirming the involvement of these structural features in the proposed mechanism.
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| 27. |
- Staaf, Henrik, 1976, et al.
(författare)
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Piezoelectric energy harvesting as energy source for autonomous intelligent wireless systems on gas turbines
- 2016
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Ingår i: EVI-GTI and PIWG Joint Conference on Gas Turbine Instrumentation, Berlin, Germany, 27-29 September 2016. - : Institution of Engineering and Technology. ; 2016:CP693
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Konferensbidrag (refereegranskat)abstract
- A collection of slides from the author's conference presentation is given: Intelligent Wireless Sensor; Vibration Harvesting; Single Cantilever Test; Coupled Harvesters; Coupling Effect; Power Consumption; Energy Storage; Packaging Tests; and Vibration Harvesting.
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| 28. |
- Webb, Dominic-Luc, et al.
(författare)
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Insulin exocytosis and glucose-mediated increase in cytoplasmic free Ca2+ concentration in the pancreatic beta-cell are independent of cyclic ADP-ribose
- 1996
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Ingår i: Journal of Biological Chemistry. - : Elsevier BV. - 0021-9258 .- 1083-351X. ; 271:32, s. 19074-19079
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Tidskriftsartikel (refereegranskat)abstract
- Stimulation of pancreatic beta-cells by glucose gives rise to an increase in the cytoplasmic free calcium concentration ([Ca2+]i) and exocytosis of insulin. Cyclic adenosine 5'-diphosphate ribose (cADPR), a metabolite of beta-NAD+, has been reported to increase [Ca2+]i in pancreatic beta-cells by releasing Ca2+ from inositol 1,4,5-trisphosphate-insensitive intracellular stores. In the present study, we have examined the role of cADPR in glucose-mediated increases in [Ca2+]i and insulin exocytosis. Dispersed ob/ob mouse beta-cell aggregates were either pressure microinjected with fura-2 salt or loaded with fura-2 acetoxymethyl ester, and [Ca2+]i was monitored by microfluorimetry. Microinjection of beta-NAD+ into fura-2-loaded beta-cells did not increase [Ca2+]i nor did it alter the cells' subsequent [Ca2+]i response to glucose. Cells microinjected with the cADPR antagonist 8NH2-cADPR increased [Ca2+]i in response to glucose equally well as those injected with cADPR. Finally, the ability of cADPR to promote exocytosis of insulin in electropermeabilized beta-cells was investigated. cADPR on its own did not increase insulin secretion nor did it potentiate Ca2+-induced insulin secretion. We conclude that cADPR neither plays a significant role in glucose-mediated increases in [Ca2+]i nor interacts directly with the molecular mechanisms regulating exocytosis of insulin in normal pancreatic beta-cells.
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| 29. |
- Yano, Jun Ich I., et al.
(författare)
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Scientific challenges of convective-scale numerical weather prediction
- 2018
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Ingår i: Bulletin of the American Meteorological Society. - 0003-0007. ; 99:4, s. 699-710
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Forskningsöversikt (refereegranskat)abstract
- Numerical weather prediction models are increasing in resolution and becoming capable of explicitly representing individual convective storms, but we do not yet know if it is the improved resolution that is leading to better forecasts.
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| 30. |
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| 31. |
- Bankel, M, et al.
(författare)
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Carious lesions and caries risk predictors in a group of Swedish children 2 to 3 years of age. One year observation
- 2011
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Ingår i: EUROPEAN JOURNAL OF PAEDIATRIC DENTISTRY. - 1591-996X. ; 12:4, s. 215-219
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: Aim Identification of potential carious risk criteria, retrospectively at 2 years of age, for developing carious lesions at 3 years of age. Study design Longitudinal observations from 2 until 3 years of age. Cross-sectional observations of two cohorts of 3- year-olds with different approaches. Materials and methods The study group consisted of 78 three- year-olds from a previous study at age 2 years. Clinical examination, diet history, questions regarding breastfeeding and salivary sampling for mutans streptococci (MS) were performed at both ages. The previous study on 124 three-year-olds was used as a control group for comparison of the 3-year-olds in the longitudinal study group. Results The examinations suggested the following risk predictors: carious lesions, frequent intake of selected sugar-containing products, breast feeding at night and MS, which covered all children with lesions at 3 years of age, resulting in a positive predictive value of 32% and a negative predictive value of 100%. The only statistically significant difference between the two groups of 3-year-olds was the reported intake of sugar-containing items. Statistics Student's t-test and chi(2) test, completed by Fischer's exact test. Conclusion The combination of the suggested risk criteria was predictive of carious lesions. In spite of individual parental information, new lesions developed after one year. Based on observations, a more structured and monitored preventive approach is suggested.
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| 32. |
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| 33. |
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| 34. |
- Bergström, Malin, et al.
(författare)
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Children with two homes: Psychological problems in relation to living arrangements in Nordic 2-to 9-year-olds
- 2019
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Ingår i: Scand J Public Health. - : SAGE Publications. - 1403-4948 .- 1651-1905. ; 47:2, s. 137-145
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Tidskriftsartikel (refereegranskat)abstract
- Aim: Joint physical custody, children spending equal time in each parents' respective home after a parental divorce, is particularly common in Nordic compared with other Western countries. Older children have been shown to fare well in this practice but for young children there are few existing studies. The aim of this paper is to study psychological problems in 2- to 9-year-old Nordic children in different family forms. Methods: Total symptom score according to the Strengths and Difficulties Questionnaire as well as scores showing externalizing problems were compared among 152 children in joint physical custody, 303 in single care and 3207 in nuclear families through multiple linear regression analyses. Results: Children in single care had more psychological symptoms than those in joint physical custody (B = 1.08; 95% CI 0.48 to 1.67) and those in nuclear families had the least reported symptoms (B = -0.53; 95% CI -0.89 to -0.17). Externalizing problems were also lower in nuclear families (B = -0.28, 95% CI -0.52 to -0.04) compared with joint physical custody after adjusting for covariates. Conclusions: Young children with non-cohabiting parents suffered from more psychological problems than those in intact families. Children in joint physical custody had a lower total problem score than those in single care after adjusting for covariates. Longitudinal studies with information on family factors before the separation are needed to inform policy of young children's post-separation living arrangements.
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| 35. |
- Björkstrand, Frida Köhler, et al.
(författare)
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Access to psychological treatment for chronic cancer-related pain in Sweden
- 2024
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Ingår i: Scandinavian Journal of Pain. - : Walter de Gruyter. - 1877-8860 .- 1877-8879. ; 24:1
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Tidskriftsartikel (refereegranskat)abstract
- Objectives Cancer-related pain (CRP) is among the most frequent collateral effects of cancer, with chronic CRP, lasting at least 3 months, affecting >40% of cancer survivors. Evidence-based treatments, including pain-focused cognitive behavioral therapy (CBT), are available, but it appears that cancer patients/survivors are often poorly informed about CRP or the potential benefits of CBT for such pain. This study examined current experience of Swedish cancer patients/survivors in relation to CRP. Methods Participants (N = 276; 83% female; mean age = 55.5 years, SD = 11.9) were recruited to an online survey via cancer websites in Sweden, and they provided information about their history of chronic CRP and whether they received information about or treatment for CRP from a healthcare professional. Results Participants had a history of breast (36%), gynecological (12%), lung (10%), colon (8%), and other forms of cancer (36%). A majority (74%) reported a history of chronic CRP and being prescribed analgesic medications (70%). Less than half (47%) received information from their healthcare provider about the risk of CRP and only 13% with chronic CRP received psychological treatment, and of these, only 33% received CBT. Among those receiving psychological treatment for chronic CRP, satisfaction rates were moderate, reported as an average of 6 on a 0-10 scale (standard deviation 2.6). Conclusions Greater efforts are needed to raise awareness among cancer patients/survivors and healthcare providers about the risk of CRP and evidence-based interventions, including CBT, the first-line intervention for chronic pain. These efforts will need to be matched with increases in treatment capacity, particularly pain-focused CBT.
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| 36. |
- Brothers, Soren M, et al.
(författare)
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A regime shift from macrophyte to phytoplankton dominance enhances carbon burial in a shallow, eutrophic lake
- 2013
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Ingår i: Ecosphere. - 2150-8925 .- 2150-8925. ; 4:11
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Tidskriftsartikel (refereegranskat)abstract
- Ecological regime shifts and carbon cycling in aquatic systems have both been subject to increasing attention in recent years, yet the direct connection between these topics has remained poorly understood. A four-fold increase in sedimentation rates was observed within the past 50 years in a shallow eutrophic lake with no surface in- or outflows. This change coincided with an ecological regime shift involving the complete loss of submerged macrophytes, leading to a more turbid, phytoplankton-dominated state. To determine whether the increase in carbon (C) burial resulted from a comprehensive transformation of C cycling pathways in parallel to this regime shift, we compared the annual C balances (mass balance and ecosystem budget) of this turbid lake to a similar nearby lake with submerged macrophytes, a higher transparency, and similar nutrient concentrations. C balances indicated that roughly 80% of the C input was permanently buried in the turbid lake sediments, compared to 40% in the clearer macrophyte-dominated lake. This was due to a higher measured C burial efficiency in the turbid lake, which could be explained by lower benthic C mineralization rates. These lower mineralization rates were associated with a decrease in benthic oxygen availability coinciding with the loss of submerged macrophytes. In contrast to previous assumptions that a regime shift to phytoplankton dominance decreases lake heterotrophy by boosting whole-lake primary production, our results suggest that an equivalent net metabolic shift may also result from lower C mineralization rates in a shallow, turbid lake. The widespread occurrence of such shifts may thus fundamentally alter the role of shallow lakes in the global C cycle, away from channeling terrestrial C to the atmosphere and towards burying an increasing amount of C.
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| 37. |
- Büttner, Barbara E, et al.
(författare)
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Quantification of isotope-labeled and unlabeled folates and folate catabolites in urine samples by stable isotope dilution assay.
- 2013
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Ingår i: International Journal for Vitamin and Nutrition Research. - : Hogrefe Publishing Group. - 0300-9831 .- 1664-2821. ; 83:2, s. 112-121
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Tidskriftsartikel (refereegranskat)abstract
- Dual-label stable isotope dilution assays for the simultaneous quantification of isotopologic folates in clinical samples offer the perspective for differentiating between unlabeled folates from endogenous body pools and administered [13C5]-labeled folates from a test dose when performing bioavailability trials. In contrast to intact folates, this methodology could hitherto not be applied to the quantification of the folate catabolites, p-aminobenzoyl glutamate and p-acetamidobenzoyl glutamate. In this study, [2H4]-p-aminobenzoyl glutamate, [2H4]-p-acetamidobenzoyl glutamate, and unlabeled p-acetamidobenzoyl glutamate were synthesized. The synthesis of the [2H4]-labeled compounds started at unlabeled p-aminobenzoic acid. For the formation of p-acetamidobenzoyl glutamate, p-aminobenzoyl glutamate was acetylated. The new substances were applied successfully in stable isotope dilution assays for the simultaneous quantification of the [13C5]-labeled and unlabeled folate catabolites, p-aminobenzoyl glutamate and p-acetamidobenzoyl glutamate, along with the predominant folate vitamers in urine. The assays were based on clean-up by strong anion exchange followed by liquid chromatography-tandem mass spectrometry detection. Assay sensitivity was sufficient to detect the folate catabolites in physiologic concentrations. The limit of detection was below 0.4 and 0.3 nmol/100 g for p-aminobenzoyl glutamate isotopologues and p-acetamidobenzoyl glutamate isotopologues in urine, respectively. The successful synthesis of [2H4]-p-aminobenzoyl glutamate, [2H4]-p-acetamidobenzoyl glutamate, and unlabeled p-acetamidobenzoyl glutamate and the implementation of these substances in stable isotope dilution assays allows dual-label designs that provide a more detailed insight into human folate metabolism.
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| 38. |
- Denoyes-Rothan, B., et al.
(författare)
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Use of a Reference Octoploid Map for Detecting Homoeologous QTLs Potentially Involved in Viability in the Cultivated Strawberry
- 2009
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Ingår i: VI INTERNATIONAL STRAWBERRY SYMPOSIUM. - : INT SOC HORTICULTURAL SCIENCE. ; , s. 537-540
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Konferensbidrag (refereegranskat)abstract
- The construction of a reference map of the complex octoploid cultivated strawberry was optimized by comparative mapping between Fragaria showing different levels of ploidy. In addition, this approach is a powerful tool for improving the detection of QTLs, and for a better understanding of the organization of these QTLs. By identifying the homoeologous linkage groups in the complex octoploid cultivated strawberry, potential homoeologous QTLs in Fragaria can be detected. The comparative mapping was based on two populations belonging to two different levels of Fragaria. The linkage map of the complex octoploid cultivated strawberry (Fragaria x ananassa Duch., 2n=8x=56) was based on a segregating population of 213 individuals of a cross between ‘Capitola’ and ‘CF1116’, two genotypes with many contrasting traits. This genetic map was compared to the diploid one, obtained from an interspecific cross between F. vesca and F. bucharica (Sargent et al., 2006). Based on 56 SSR markers common to both diploid and octoploid genetic maps, almost all linkage groups of the genetic octoploid map were arranged into the seven homoeologous groups (HGs) expected for the genus Fragaria, which belongs to the tribe Rosoideae. For each trait, QTLs can potentially be detected on each linkage group belonging to the same HG. Results showed detection of homoeologous chromosomal regions potentially involved in viability of the plant.
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| 39. |
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| 40. |
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| 41. |
- Erlandsson, M., et al.
(författare)
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Spatial and temporal variations of base cation release from chemical weathering on a hillslope scale
- 2016
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Ingår i: Chemical Geology. - : Elsevier BV. - 0009-2541 .- 1872-6836. ; 441, s. 1-13
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Tidskriftsartikel (refereegranskat)abstract
- Cation release rates to catchment runoff from chemical weathering were assessed using an integrated catchment model that included the soil's unsaturated, saturated and riparian zones. In-situ mineral dissolution rates were calculated in these zones as a function of pH, aluminum and dissolved organic carbon (DOC) concentrations along a hillslope in Northern Sweden where soil water was monitored over nine years. Three independent sets of mineral dissolution equations of varying complexity were used: PROFILE, Transition-State Theory (TST), and the Palandri & Kharaka database. Normalization of the rate-coefficients was necessary to compare the equations, as published rate-coefficients gave base cation release rates differing by several orders of magnitude. After normalizing the TST- and Palandri & Kharaka-rate coefficients to match the base cation release rates calculated from the PROFILE-equations, calculated Ca2 + and Mg2 + release rates are consistent with mass balance calculations, whereas those of Na+ and K+ are overestimated. Our calculations further indicate that a significant proportion of base cations are released from the organic soils in the near-stream zone, in part due to its finer texture. Of the three sets of rate equations, the base cation release rates calculated from the normalized TST-equations were more variable than those calculated using the other two sets of equations, both spatially and temporally, due to its higher sensitivity to pH. In contrast, the normalized Palandri & Kharaka-equations were more sensitive to variations in soil temperature.
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| 42. |
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| 43. |
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| 44. |
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| 45. |
- Haas, Jan, et al.
(författare)
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Atlas of the clinical genetics of human dilated cardiomyopathy
- 2015
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Ingår i: European Heart Journal. - : Oxford University Press. - 0195-668X .- 1522-9645. ; 36:18, s. 1123-U43
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Tidskriftsartikel (refereegranskat)abstract
- Aim: We were able to show that targeted Next-Generation Sequencing is well suited to be applied in clinical routine diagnostics, substantiating the ongoing paradigm shift from low- to high-throughput genomics in medicine. By means of our atlas of the genetics of human DCM, we aspire to soon be able to apply our findings to the individual patient with cardiomyopathy in daily clinical practice. Numerous genes are known to cause dilated cardiomyopathy (DCM). However, until now technological limitations have hindered elucidation of the contribution of all clinically relevant disease genes to DCM phenotypes in larger cohorts. We now utilized next-generation sequencing to overcome these limitations and screened all DCM disease genes in a large cohort. Methods and results: In this multi-centre, multi-national study, we have enrolled 639 patients with sporadic or familial DCM. To all samples, we applied a standardized protocol for ultra-high coverage next-generation sequencing of 84 genes, leading to 99.1% coverage of the target region with at least 50-fold and a mean read depth of 2415. In this well characterized cohort, we find the highest number of known cardiomyopathy mutations in plakophilin-2, myosin-binding protein C-3, and desmoplakin. When we include yet unknown but predicted disease variants, we find titin, plakophilin-2, myosin-binding protein-C 3, desmoplakin, ryanodine receptor 2, desmocollin-2, desmoglein-2, and SCN5A variants among the most commonly mutated genes. The overlap between DCM, hypertrophic cardiomyopathy (HCM), and channelopathy causing mutations is considerably high. Of note, we find that >38% of patients have compound or combined mutations and 12.8% have three or even more mutations. When comparing patients recruited in the eight participating European countries we find remarkably little differences in mutation frequencies and affected genes. Conclusion: This is to our knowledge, the first study that comprehensively investigated the genetics of DCM in a large-scale cohort and across a broad gene panel of the known DCM genes. Our results underline the high analytical quality and feasibility of Next-Generation Sequencing in clinical genetic diagnostics and provide a sound database of the genetic causes of DCM.
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| 46. |
- Hassler, Donald M., et al.
(författare)
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Mars’ surface radiation environment measured with the Mars Science Laboratory’s Curiosity Rover
- 2014
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 343:6169
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Tidskriftsartikel (refereegranskat)abstract
- The Radiation Assessment Detector (RAD) on the Mars Science Laboratory’s Curiosity rover began making detailed measurements of the cosmic ray and energetic particle radiation environment on the surface of Mars on 7 August 2012. We report and discuss measurements of the absorbed dose and dose equivalent from galactic cosmic rays and solar energetic particles on the martian surface for ~300 days of observations during the current solar maximum. These measurements provide insight into the radiation hazards associated with a human mission to the surface of Mars and provide an anchor point with which to model the subsurface radiation environment, with implications for microbial survival times of any possible extant or past life, as well as for the preservation of potential organic biosignatures of the ancient martian environment.
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| 47. |
- Heaton, T. J., et al.
(författare)
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Radiocarbon : A key tracer for studying Earth’s dynamo, climate system, carbon cycle, and Sun
- 2021
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 374:6568
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Forskningsöversikt (refereegranskat)abstract
- Radiocarbon (14C), as a consequence of its production in the atmosphere and subsequent dispersal through the carbon cycle, is a key tracer for studying the Earth system. Knowledge of past 14C levels improves our understanding of climate processes, the Sun, the geodynamo, and the carbon cycle. Recently updated radiocarbon calibration curves (IntCal20, SHCal20, and Marine20) provide unprecedented accuracy in our estimates of 14C levels back to the limit of the 14C technique (~55,000 years ago). Such improved detail creates new opportunities to probe the Earth and climate system more reliably and at finer scale. We summarize the advances that have underpinned this revised set of radiocarbon calibration curves, survey the broad scientific landscape where additional detail on past 14C provides insight, and identify open challenges for the future.
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| 48. |
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| 49. |
- Keucken, Alexander, et al.
(författare)
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Combined coagulation and ultrafiltration process to counteract increasing NOM in brown surface water
- 2017
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Ingår i: Water. - : MDPI AG. - 2073-4441. ; 9:9
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Tidskriftsartikel (refereegranskat)abstract
- Membrane hybrid processes-coagulation coupled with ultrafiltration (UF)-have become a common method to comply with the legal, chemical, and microbiological requirements for drinking water. The main advantages of integrating coagulation with membrane filtration are the enhanced removal of natural organic matter (NOM) and reduced membrane fouling. With in-line coagulation, coagulants are patched into the feed stream directly prior to the membrane process, without removing the coagulated solids. Compared with conventional coagulation/sedimentation, in-line coagulation/membrane reduces the treatment time and footprint. Coagulant dosing could be challenging in raw water of varying quality; however, with relatively stable specific ultraviolet absorbance (SUVA), dosing can be controlled. Recent studies indicate that UV absorbance correlates well with humic substances (HS), the major fraction to be removed during coagulation. This paper describes and evaluates a 30-month UF pilot trial on the surface water of Lake Neden (Sweden), providing drinking water to 60,000 residents. In this study, automatic coagulant dosing based on online measurement was successfully applied. Online sensor data were used to identify the current optimal aluminium coagulation conditions (0.5-0.7 mg L-1) and the potential boundaries (0.9-1.2 mg L-1) for efficient future (2040) NOM removal. The potential increase in NOM could affect the Al dose and drinking water quality significantly within 20 years, should the current trends in dissolved organic carbon (DOC) prevail. UV absorbance, the freshness index, and liquid chromatography-organic carbon detection (LC-OCD) measurements were used to optimise the process. Careful cross-calibration of raw and filtered samples is recommended when using online sensor data for process optimisation, even in low-turbidity water (formazin nephelometric unit (FNU) < 5).
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| 50. |
- Kim, Myung-Hee Y., et al.
(författare)
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Comparison of Martian surface ionizing radiation measurements from MSL-RAD with Badhwar-O'Neill 2011/HZETRN model calculations
- 2014
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Ingår i: Journal of Geophysical Research - Planets. - 2169-9097 .- 2169-9100. ; 119:6, s. 1311-1321
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Tidskriftsartikel (refereegranskat)abstract
- Dose rate measurements from Mars Science Laboratory-radiation assessment detector (MSL-RAD) for 300 sols on Mars are compared to simulation results using the Badhwar-O'Neill 2011 galactic cosmic ray (GCR) environment model and the high-charge and energy transport (HZETRN) code. For the nuclear interactions of primary GCR through Mars atmosphere and Curiosity rover, the quantum multiple scattering theory of nuclear fragmentation is used. Daily atmospheric pressure is measured at Gale Crater by the MSL Rover Environmental Monitoring Station. Particles impinging on top of the Martian atmosphere reach RAD after traversing varying depths of atmosphere that depend on the slant angles, and the model accounts for shielding of the RAD “E” detector (used for dosimetry) by the rest of the instrument. Simulation of average dose rate is in good agreement with RAD measurements for the first 200 sols and reproduces the observed variation of surface dose rate with changing heliospheric conditions and atmospheric pressure. Model results agree less well between sols 200 and 300 due to subtleties in the changing heliospheric conditions. It also suggests that the average contributions of albedo particles (charge number Z < 3) from Martian regolith comprise about 10% and 42% of the average daily point dose and dose equivalent, respectively. Neutron contributions to tissue-averaged effective doses will be reduced compared to point dose equivalent estimates because a large portion of the neutron point dose is due to low-energy neutrons with energies.
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