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Sökning: WFRF:(Ström Anders)

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1.
  • Gunnarsson, Rebeqa, et al. (författare)
  • Mutation, methylation, and gene expression profiles in dup(1q)-positive pediatric B-cell precursor acute lymphoblastic leukemia
  • 2018
  • Ingår i: Leukemia. - : Springer Science and Business Media LLC. - 0887-6924 .- 1476-5551. ; 32:10, s. 2117-2125
  • Tidskriftsartikel (refereegranskat)abstract
    • High-throughput sequencing was applied to investigate the mutation/methylation patterns on 1q and gene expression profiles in pediatric B-cell precursor acute lymphoblastic leukemia (BCP ALL) with/without (w/wo) dup(1q). Sequencing of the breakpoint regions and all exons on 1q in seven dup(1q)-positive cases revealed non-synonymous somatic single nucleotide variants (SNVs) in BLZF1, FMN2, KCNT2, LCE1C, NES, and PARP1. Deep sequencing of these in a validation cohort w (n = 17)/wo (n = 94) dup(1q) revealed similar SNV frequencies in the two groups (47% vs. 35%; P = 0.42). Only 0.6% of the 36,259 CpGs on 1q were differentially methylated between cases w (n = 14)/wo (n = 13) dup(1q). RNA sequencing of high hyperdiploid (HeH) and t(1;19)(q23;p13)-positive cases w (n = 14)/wo (n = 52) dup(1q) identified 252 and 424 differentially expressed genes, respectively; only seven overlapped. Of the overexpressed genes in the HeH and t(1;19) groups, 23 and 31%, respectively, mapped to 1q; 60-80% of these encode nucleic acid/protein binding factors or proteins with catalytic activity. We conclude that the pathogenetically important consequence of dup(1q) in BCP ALL is a gene-dosage effect, with the deregulated genes differing between genetic subtypes, but involving similar molecular functions, biological processes, and protein classes.
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  • Backman, Helena, et al. (författare)
  • Lung function trajectories and associated mortality among adults with and without airway obstruction
  • 2023
  • Ingår i: American Journal of Respiratory and Critical Care Medicine. - : American Thoracic Society. - 1073-449X .- 1535-4970. ; 208:10, s. 1063-1074
  • Tidskriftsartikel (refereegranskat)abstract
    • Rationale: Spirometry is essential for diagnosis and assessment of prognosis in COPD.Objectives: To identify FEV1 trajectories and their determinants, based on annual spirometry measurements among individuals with and without airway obstruction. Furthermore, to assess mortality in relation to trajectories.Methods: In 2002-04, individuals with airway obstruction (AO) (FEV1/VC<0.70, n=993) and age- and sex-matched non-obstructive (NO) referents were recruited from population-based cohorts. Annual spirometries until 2014 were utilized in joint-survival Latent Class Mixed Models to identify lung function trajectories. Mortality data were collected during 15 years of follow-up.Results: Three trajectories were identified among the AO-cases and two among the NO referents. Trajectory membership was driven by baseline FEV1%predicted (%pred) in both groups and additionaly, pack-years in AO and current smoking in NO. Longitudinal FEV1%pred level depended on baseline FEV1%pred, pack-years and obesity. The trajectories were distributed: 79.6% T1AO FEV1-high with normal decline, 12.8% T2AO FEV1-high with rapid decline, and 7.7% T3AO FEV1-low with normal decline (mean 27, 72 and 26 mL/year) among AO-individuals, and 96.7% T1NO FEV1-high with normal decline and 3.3% T2NO FEV1-high with rapid decline (mean 34 and 173 mL/year) among referents. Hazard for death was increased for T2AO (HR1.56) and T3AO (HR3.45) vs. T1AO, and for T2NO (HR2.99) vs. T1NO.Conclusions: Three different FEV1 trajectories were identified among those with airway obstruction and two among the referents, with different outcomes in terms of FEV1-decline and mortality. The FEV1 trajectories among airway obstructive and the relationship between low FVC and trajectory outcome are of particular clinical interest.
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  • Boman, Christoffer, et al. (författare)
  • Development of innovative small(micro)-scale biomass-based CHP technologies
  • 2017
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • To enhance the overall efficiency of the use of biomass in the energy sector in Europe, the large electricity production potential from small-scale biomass heating systems should be utilised. So far, no technologically sound (in terms of efficiency and reliability) and economically affordable micro- and small-scale biomass CHP technologies are, however, available. Therefore, the present ERA-NET project (MiniBioCHP) aimed at the further development and test of new CHP technologies based on small-scale biomass combustion in the electric capacity range between some W and 100 kW. Within the project, an international consortium consisting of 12 partners from 4 countries, including university institutions, institutes and industry (both engineering and manufacturing), collaborated closely to perform high level R&D on three promising micro/small-scale biomass based CHP technologies which are covering a broad range of applications in the residential heating sector. The Austrian engineering company BIOS, coordinated the international project. The project was based on earlier basic research and development work related to these promising new technologies and aimed at the achievement of a technological level which allows a first (commercial) demonstration after the end of the project. The three CHP concepts included in the MiniBioCHP project were;1. Pellet stoves with a thermoelectric generator (TEG)2. Small-scale biomass boilers (10-30 kWth) with a micro-ORC process3. High temperature heat exchanger (HT-HE) for an externally fired gas turbine (EFGT)The Swedish part of the project was focused on the development of the concept of biomass based EFGT with dedicated R&D activities related to the development of the HT-HE system. The Swedish project consisted of the research partners Umeå University (project leader), Luleå University of Technology, Chalmers University of Technology and RISE Research Institutes of Sweden, together with the industrial partners Enertech AB/Osby Parca and Ecergy. The expertise of the Swedish partners regarding ash related problems, grate boiler combustion and modelling, deposit formation and high temperature corrosion, were combined with the know-how of a Polish partner regarding HT-HE design, construction, testing and optimisation.The HT-HE is the most crucial component in EFGT processes significantly influencing the investment costs, availabilities as well as the efficiencies that can be achieved. With a thermal capacity from several hundred kW up to 2-3 MWth) the CHP technology based on a biomass boiler and an EFGT is suitable for district heating systems, or process heat consumers. The electricity produced by the gas turbine (up to some 100 kWel) can be used to cover the own electricity consumption of a company and/or fed into the grid. Even though the concept of biomass based EFGT has been an interesting alternative for small-scale CHP production for some decades, and R&D activities have been undertaken, tackling both economic and technical aspects, only a few pilot-plants have been in operation and no initiative has so far reached the level of commercial implementation. Thus, the concept of EFGT fed with biomass is still considered to be in a rather early development stage and the main technical challenges are related to alkali deposit induced corrosion and thermal stress of the HT-HE material, turbine design/operation and system integration.Within the present project, a HT-HE prototype aimed for an EFGT system was therefore designed, constructed and successfully tested at flue gas temperatures up to 900°C. Thus, appropriate guidelines for a compact design of the HT-HE and recommendations have been worked out to minimize thermal stresses as well as ash related problems regarding ash deposit formation and high temperature corrosion in a biomass boiler system. Furthermore, different concepts for the overall biomass based EFGT system have been worked out and evaluated. The outcome of the project will hopefully be used in the further development work and form the basis for a first testing and demonstration plant within the coming years.
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  • Bombarda, F., et al. (författare)
  • Runaway electron beam control
  • 2019
  • Ingår i: Plasma Physics and Controlled Fusion. - : IOP Publishing. - 1361-6587 .- 0741-3335. ; 61:1
  • Tidskriftsartikel (refereegranskat)
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  • Eriksson, Jan W., et al. (författare)
  • Hydrochlorothiazide, but not Candesartan, aggravates insulin resistance and causes visceral and hepatic fat accumulation : the mechanisms for the diabetes preventing effect of Candesartan (MEDICA) Study
  • 2008
  • Ingår i: Hypertension. - : American Heart Association. - 0194-911X .- 1524-4563. ; 52:6, s. 1030-1037
  • Tidskriftsartikel (refereegranskat)abstract
    • Treatment with angiotensin II receptor blockers is associated with lower risk for the development of type 2 diabetes mellitus compared with thiazide diuretics. The Mechanisms for the Diabetes Preventing Effect of Candesartan Study addressed insulin action and secretion and body fat distribution after treatment with candesartan, hydrochlorothiazide, and placebo. Twenty-six nondiabetic, abdominally obese, hypertensive patients were included in a multicenter 3-way crossover trial, and 22 completers (by predefined criteria; 10 men and 12 women) were included in the analyses. They underwent 12-week treatment periods with candesartan (C; 16 to 32 mg), hydrochlorothiazide (H; 25 to 50 mg), and placebo (P), respectively, and the treatment order was randomly assigned and double blinded. Intravenous glucose tolerance tests and euglycemic hyperinsulinemic (56 mU/m(2) per minute) clamps were performed. Intrahepatic and intramyocellular and extramyocellular lipid content and subcutaneous and visceral abdominal adipose tissue were measured using proton magnetic resonance spectroscopy and MRI. Insulin sensitivity (M-value) was reduced following H versus C and P (6.07+/-2.05, 6.63+/-2.04, and 6.90+/-2.10 mg/kg of body weight per minute, mean+/-SD; P
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  • Eriksson Ström, Jonas, et al. (författare)
  • Airway regulatory T cells are decreased in COPD with a rapid decline in lung function
  • 2020
  • Ingår i: Respiratory Research. - : BioMed Central. - 1465-9921 .- 1465-993X. ; 21:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Differences in the expression of regulatory T cells (Tregs) have been suggested to explain why some smokers develop COPD and some do not. Upregulation of Tregs in response to smoking would restrain airway inflammation and thus the development of COPD; while the absense of such upregulation would over time lead to chronic inflammation and COPD. We hypothesized that—among COPD patients—the same mechanism would affect rate of decline in lung function; specifically, that a decreased expression of Tregs would be associated with a more rapid decline in FEV1.Methods: Bronchoscopy with BAL was performed in 52 subjects recruited from the longitudinal OLIN COPD study; 12 with COPD and a rapid decline in lung function (loss of FEV1 ≥ 60 ml/year), 10 with COPD and a non-rapid decline in lung function (loss of FEV1 ≤ 30 ml/year), 15 current and ex-smokers and 15 non-smokers with normal lung function. BAL lymphocyte subsets were determined using flow cytometry.Results: The proportions of Tregs with regulatory function (FoxP3+/CD4+CD25bright) were significantly lower in COPD subjects with a rapid decline in lung function compared to those with a non-rapid decline (p = 0.019). This result was confirmed in a mixed model regression analysis in which adjustments for inhaled corticosteroid usage, smoking, sex and age were evaluated. No significant difference was found between COPD subjects and smokers or non-smokers with normal lung function.Conclusions: COPD subjects with a rapid decline in lung function had lower proportions of T cells with regulatory function in BAL fluid, suggesting that an inability to suppress the inflammatory response following smoking might lead to a more rapid decline in FEV1.
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  • Eriksson Ström, Jonas, et al. (författare)
  • Cytotoxic lymphocytes in COPD airways : increased NK cells associated with disease, iNKT and NKT-like cells with current smoking
  • 2018
  • Ingår i: Respiratory Research. - : BMC. - 1465-9921 .- 1465-993X. ; 19
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Cytotoxic lymphocytes are increased in the airways of COPD patients. Whether this increase is driven primarily by the disease or by smoking is not clear, nor whether it correlates with the rate of decline in lung function.Methods: Bronchoscopy with BAL was performed in 52 subjects recruited from the longitudinal OLIN COPD study according to pre-determined criteria; 12 with COPD and a rapid decline in lung function (loss of FEV1 ≥ 60 ml/year), 10 with COPD and a non-rapid decline in lung function (loss of FEV1 ≤ 30 ml/year), 15 current and ex-smokers and 15 non-smokers with normal lung function. BAL lymphocyte subsets were determined using flow cytometry.Results: In BAL fluid, the proportions of NK, iNKT and NKT-like cells all increased with pack-years. Within the COPD group, NK cells – but not iNKT or NKT-like cells – were significantly elevated also in subjects that had quit smoking. In contrast, current smoking was associated with a marked increase in iNKT and NKT-like cells but not in NK cells. Rate of lung function decline did not significantly affect any of the results.Conclusions: In summary, increased proportions of NK cells in BAL fluid were associated with COPD; iNKT and NKT-like cells with current smoking but not with COPD. Interestingly, NK cell percentages did not normalize in COPD subjects that had quit smoking, indicating that these cells might play a role in the continued disease progression seen in COPD even after smoking cessation.Trial registration: Clinicaltrials.gov identifier NCT02729220.
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  • Gaines, Hans, et al. (författare)
  • Six-week follow-up after HIV-1 exposure: a position statement from the Public Health Agency of Sweden and the Swedish Reference Group for Antiviral Therapy
  • 2016
  • Ingår i: Infectious Diseases. - : Informa UK Limited. - 2374-4235 .- 2374-4243. ; 48:2, s. 93-98
  • Forskningsöversikt (refereegranskat)abstract
    • In 2014 the Public Health Agency of Sweden and the Swedish Reference Group for Antiviral Therapy (RAV) conducted a review and analysis of the state of knowledge on the duration of follow-up after exposure to human immunodeficiency virus (HIV). Up until then a follow-up of 12 weeks after exposure had been recommended, but improved tests and new information on early diagnosis motivated a re-evaluation of the national recommendations by experts representing infectious diseases and microbiology, county medical officers, the RAV, the Public Health Agency, and other national authorities. Based on the current state of knowledge the Public Health Agency of Sweden and the RAV recommend, starting in April 2015, a follow-up period of 6 weeks after possible HIV-1 exposure, if HIV testing is performed using laboratory-based combination tests detecting both HIV antibody and antigen. If point-of-care rapid HIV tests are used, a follow-up period of 8 weeks is recommended, because currently available rapid tests have insufficient sensitivity for detection of HIV-1 antigen. A follow-up period of 12 weeks is recommended after a possible exposure for HIV-2, since presently used assays do not include HIV-2 antigens and only limited information is available on the development of HIV antibodies during early HIV-2 infection. If pre- or post-exposure prophylaxis is administered, the follow-up period is recommended to begin after completion of prophylaxis. Even if infection cannot be reliably excluded before the end of the recommended follow-up period, HIV testing should be performed at first contact for persons who seek such testing.
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  • Joffrin, E., et al. (författare)
  • Overview of the JET preparation for deuterium-tritium operation with the ITER like-wall
  • 2019
  • Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 59:11
  • Forskningsöversikt (refereegranskat)abstract
    • For the past several years, the JET scientific programme (Pamela et al 2007 Fusion Eng. Des. 82 590) has been engaged in a multi-campaign effort, including experiments in D, H and T, leading up to 2020 and the first experiments with 50%/50% D-T mixtures since 1997 and the first ever D-T plasmas with the ITER mix of plasma-facing component materials. For this purpose, a concerted physics and technology programme was launched with a view to prepare the D-T campaign (DTE2). This paper addresses the key elements developed by the JET programme directly contributing to the D-T preparation. This intense preparation includes the review of the physics basis for the D-T operational scenarios, including the fusion power predictions through first principle and integrated modelling, and the impact of isotopes in the operation and physics of D-T plasmas (thermal and particle transport, high confinement mode (H-mode) access, Be and W erosion, fuel recovery, etc). This effort also requires improving several aspects of plasma operation for DTE2, such as real time control schemes, heat load control, disruption avoidance and a mitigation system (including the installation of a new shattered pellet injector), novel ion cyclotron resonance heating schemes (such as the three-ions scheme), new diagnostics (neutron camera and spectrometer, active Alfven eigenmode antennas, neutral gauges, radiation hard imaging systems...) and the calibration of the JET neutron diagnostics at 14 MeV for accurate fusion power measurement. The active preparation of JET for the 2020 D-T campaign provides an incomparable source of information and a basis for the future D-T operation of ITER, and it is also foreseen that a large number of key physics issues will be addressed in support of burning plasmas.
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  • Malinovschi, Andrei, 1978-, et al. (författare)
  • Consequences of Using Post- or Prebronchodilator Reference Values in Interpreting Spirometry
  • 2023
  • Ingår i: American Journal of Respiratory and Critical Care Medicine. - : American Thoracic Society. - 1073-449X .- 1535-4970. ; 208:4, s. 461-471
  • Tidskriftsartikel (refereegranskat)abstract
    • RATIONALE: Post-bronchodilator (BD) spirometry is used for diagnosis of chronic obstructive pulmonary disease (COPD). However, pre-BD reference values are used for spirometry interpretation.OBJECTIVES: To compare the resulting prevalence rates of abnormal spirometry and study the consequences of using pre- or post-BD reference values generated within the Swedish CArdioPulmonary bioImage Study (SCAPIS) when interpreting post-BD spirometry in a general population.METHODS: SCAPIS reference values for post-BD and pre-BD spirometry were based on 10,156 and 1,498 never-smoking, healthy participants, respectively. We studied the associations of abnormal spirometry, defined by using pre- or post-BD reference values, with respiratory burden in the SCAPIS general population (28,851 individuals).MEASUREMENTS AND MAIN RESULTS: Bronchodilation resulted in higher predicted median and lower limit of normal (LLN) for FEV1/FVC ratio. The prevalence of post-BD FEV1/FVC < pre-bronchodilator LLN was 4.8% and that of post-BD FEV1/FVC < post-bronchodilator LLN was 9.9% for the general population. An additional 5.1% was identified as having an abnormal post-BD FEV1/FVC ratio and this group had more respiratory symptoms, emphysema (13.5% vs. 4.1%, p<0.001) and self-reported physician-diagnosed COPD (2.8% vs. 0.5%, p<0.001) than subjects with post-BD FEV1/FVC ratio > LLN for both pre- and post-bronchodilation).CONCLUSIONS: Pre- and post-bronchodilator spirometry reference values differ with regard to FEV1/FVC ratio. Use of post-bronchodilator reference values doubled the population prevalence of airflow obstruction; this was related to a higher respiratory burden. Using post-bronchodilator reference values when interpreting post-bronchodilator spirometry might enable identification of individuals with mild disease and be clinically relevant.
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  • Sjöberg, Mats, 1965-, et al. (författare)
  • Infliximab or cyclosporine as rescue therapy in hospitalized patients with steroid-refractory ulcerative colitis : a retrospective observational study
  • 2012
  • Ingår i: Inflammatory Bowel Diseases. - : John Wiley & Sons. - 1078-0998 .- 1536-4844. ; 18:2, s. 212-218
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Cyclosporine (CsA) or infliximab (IFX) are used as rescue therapies in steroid-refractory, severe attacks of ulcerative colitis (UC). There are no data comparing the efficacy of these two alternatives. Methods: Outcome of rescue therapy was retrospectively studied in two cohorts of patients hospitalized due to steroid-refractory moderate to severe UC: 1) a Swedish-Danish cohort (n 49) treated with a single infusion of IFX; 2) an Austrian cohort (n 43) treated with intravenous CsA. After successful rescue therapy, maintenance immunomodulator treatment was given to 27/33 (82%) of IFX patients and to 31/40 (78%) of CsA patients. Endpoints were colectomy-free survival at 3 and 12 months. Kaplan-Meier and Cox regression models were used to evaluate the association between treatment groups and colectomy. Results: At 15 days, colectomy-free survival in the IFX cohort was 36/49 (73%) versus 41/43 (95%) in the CsA cohort (P = 0.005), at 3 months 33/49 (67%) versus 40/43 (93%) (P = 0.002), and at 12 months 28/49 (57%) versus 33/43 (77%) (P = 0.034). After adjusting for potential confounding factors, Cox regression analysis yielded adjusted hazard ratios for risk of colectomy in IFX-treated patients of 11.2 (95% confidence interval [CI] 2.4-53.1, P = 0.002) at 3 months and of 3.0 (95% CI 1.1-8.2, P = 0.030) at 12 months in comparison with CsA-treated patients. There were no opportunistic infections or mortality. Conclusions: Colectomy frequencies were significantly lower after rescue therapy with CsA than with a single infusion of IFX both at 3 and 12 months' follow-up. The superiority of CsA was seen principally during the first 15 days.
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  • Ström, Linda, 1985, et al. (författare)
  • Catalytically Active Pd–Ag Alloy Nanoparticles Synthesized in Microemulsion Template
  • 2018
  • Ingår i: Langmuir. - : American Chemical Society (ACS). - 1520-5827 .- 0743-7463. ; 34:33, s. 9754-9761
  • Tidskriftsartikel (refereegranskat)abstract
    • This work investigates the possibility to form catalytically active bimetallic Pd–Ag nanoparticles synthesized in the water pools of a reversed microemulsion using methanol, a more environmental- and user-friendly reductant compared to hydrazine or sodium borohydride, which are commonly used for this type of synthesis. The nanoparticles were characterized with regards to crystallinity and size by X-ray diffraction and transmission electron microscopy. CO chemisorption and oxidation followed by in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) was used for investigating the elemental composition of the surface and catalytic activity, respectively. Moreover, the structural composition of the bimetallic particles was determined by scanning transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy. The particles were shown to be crystalline nanoalloys of around 5–12 nm. CO adsorption followed by in situ DRIFTS suggests that the particle surfaces are composed of the same Pd–Ag ratios as the entire particles, regardless of elemental ratio (i.e., no core–shell structures can be detected). This is also shown by numerical simulations using a Monte Carlo based model. Furthermore, CO oxidation confirms that the synthesized particles are catalytically active.
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  • Ström, Linda, 1985, et al. (författare)
  • Quantification of urea-spray non-uniformity effects on the H2-assisted NO reduction and NH3 slip over an Ag/Al2O3 catalyst
  • 2015
  • Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 75, s. 2317-2322
  • Konferensbidrag (refereegranskat)abstract
    • Selective catalytic reduction of nitrogen oxides (NOx) with ammonia (NH3-SCR) is an efficient technology for lean NOx removal in automotive applications. In the current work, a kinetic model for hydrogen-assisted NH3-SCR over a silver-alumina (Ag/Al2O3) monolith catalyst is adapted to the corresponding experimental results. The degree of non-uniformity in the NH3 dose to individual catalyst channels during operation of a urea-SCR system is also investigated and the NH3 dose probability distribution functions are derived. The effects of NH3 non-uniformity on the NO conversion and NH3 slip are studied over an otherwise optimal Ag/Al2O3 system. Above the stoichiometric point, the NH3 slip is shown to increase almost linearly with increasing NH3 dosage. Channels that receive significantly lower NH3 dose than the stoichiometric one exhibit low NO conversion, whereas there is no discernable increase in the NO conversion above an NH3 dose four times the average. These results highlight the importance of the interaction between the design of the NH3 dosing system and the performance of the catalytic system.
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  • Torén, Kjell, 1952, et al. (författare)
  • The ratio FEV1/FVC and its association to respiratory symptoms-A Swedish general population study
  • 2021
  • Ingår i: Clinical Physiology and Functional Imaging. - : Wiley. - 1475-0961 .- 1475-097X. ; 41:2, s. 181-191
  • Tidskriftsartikel (refereegranskat)abstract
    • Chronic airflow limitation (CAL) can be defined as fixed ratio of forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) any respiratory symptom. In a cross-sectional general population study, 15,128 adults (50-64 years of age), 7,120 never-smokers and 8,008 ever-smokers completed a respiratory questionnaire and performed FEV1 and FVC after bronchodilation. We calculated different ratios of FEV1/FVC from 0.40 to 1.0 using 0.70 as reference category. We analysed odds ratios (OR) between different ratios and any respiratory symptom using adjusted multivariable logistic regression. Among all subjects, regardless of smoking habits, the lowest odds for any respiratory symptom was at FEV1/FVC = 0.82, OR 0.48 (95% CI 0.41-0.56). Among never-smokers, the lowest odds for any respiratory symptom was at FEV1/FVC = 0.81, OR 0.53 (95% CI 0.41-0.70). Among ever-smokers, the odds for any respiratory symptom was lowest at FEV1/FVC = 0.81, OR 0.43 (95% CI 0.16-1.19), although the rate of inclining in odds was small in the upper part, that is FEV1/FVC = 0.85 showed similar odds, OR 0.45 (95% CI 0.38-0.55). We concluded that the odds for any respiratory symptoms continuously decreased with higher FEV1/FVC ratios and reached a minimum around 0.80-0.85, with similar results among never-smokers. These results indicate that the optimal threshold associated with respiratory symptoms may be higher than 0.70 and this should be further investigated in prospective longitudinal studies.
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  • Agåker, Marcus, et al. (författare)
  • Novel instruments for ultra-soft X-ray emission spectroscopy
  • 2009
  • Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 601:1-2, s. 213-219
  • Tidskriftsartikel (refereegranskat)abstract
    • Two alternative instrument designs to the traditional Rowland grating spectrometer for high resolution ultra-soft X-ray spectroscopy are presented. The first instrument is a plane grating spectrometer using off-axis parabolic mirrors for collection and refocusing, and with a spatially resolving multichannel detector with delay line read-out. The instrument offers substantially higher performance in terms of resolution and sensitivity than traditional instruments. The second instrument is a Fourier transform spectrometer based on a grazing incidence Mach-Zehnder interferometer using wavefront dividing beamsplitters. The path length difference can be scanned over 0.1 mm, which corresponds to a resolution of 12 meV. (C) 2009 Elsevier B.V. All rights reserved.
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  • Aho-Mantila, L., et al. (författare)
  • Assessment of SOLPS5.0 divertor solutions with drifts and currents against L-mode experiments in ASDEX Upgrade and JET
  • 2017
  • Ingår i: Plasma Physics and Controlled Fusion. - : IOP PUBLISHING LTD. - 0741-3335 .- 1361-6587. ; 59:3
  • Tidskriftsartikel (refereegranskat)abstract
    • The divertor solutions obtained with the plasma edge modelling tool SOLPS5.0 are discussed. The code results are benchmarked against carefully analysed L-mode discharges at various density levels with and without impurity seeding in the full-metal tokamaks ASDEX Upgrade and JET. The role of the cross-field drifts and currents in the solutions is analysed in detail, and the improvements achieved by fully activating the drift and current terms in view of matching the experimental signals are addressed. The persisting discrepancies are also discussed.
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  • Albinsson, David, 1990, et al. (författare)
  • Copper catalysis at operando conditions - bridging the gap between single nanoparticle probing and catalyst-bed-averaging
  • 2020
  • Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723 .- 2041-1723. ; 11:1
  • Tidskriftsartikel (refereegranskat)abstract
    • In catalysis, nanoparticles enable chemical transformations and their structural and chemical fingerprints control activity. To develop understanding of such fingerprints, methods studying catalysts at realistic conditions have proven instrumental. Normally, these methods either probe the catalyst bed with low spatial resolution, thereby averaging out single particle characteristics, or probe an extremely small fraction only, thereby effectively ignoring most of the catalyst. Here, we bridge the gap between these two extremes by introducing highly multiplexed single particle plasmonic nanoimaging of model catalyst beds comprising 1000 nanoparticles, which are integrated in a nanoreactor platform that enables online mass spectroscopy activity measurements. Using the example of CO oxidation over Cu, we reveal how highly local spatial variations in catalyst state dynamics are responsible for contradicting information about catalyst active phase found in the literature, and identify that both surface and bulk oxidation state of a Cu nanoparticle catalyst dynamically mediate its activity.
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  • Andersson Höök, Lars, et al. (creator_code:cre_t)
  • Vältalighetens dubbla ansikte : Två svenska 1600-talsorationer om talekonstens politiska användning: Text – kontext – intertext. Inledning Nils Ekedahl. Textinledning, utgåva och översättning Annika Ström
  • 2023. - 1
  • Bok (refereegranskat)abstract
    • Här presenteras två latinska orationer, hållna i Uppsala 1654. I centrum för dem står retorikens användbarhet som politiskt redskap. Tillsammans skildrar de en talekonst med dubbelt ansikte: medan den ena orationen utmålar retoriken som en försåtlig manipulationskonst framställer den andra den som fundamentet för varje civiliserat samhälle. Var retoriken ond eller god? Något entydigt svar ger inte orationerna.Vad som gör orationerna märkliga är att de kan läsas som inlägg i den politiska strid som i det fördolda rasade just vid denna tid, nämligen den nye svenske kungen Karl X Gustavs planer på att starta krig mot Polen. Samtidigt som orationerna demonstrerar renässansens syn på retoriken som politiskt verktyg ger de oväntade inblickar i tidens politiska opinionsbildning.
  •  
42.
  • Andersson Sundén, Erik, et al. (författare)
  • An assessment of nitrogen concentrations from spectroscopic measurements in the JET and ASDEX upgrade divertor
  • 2019
  • Ingår i: Nuclear Materials and Energy. - : Elsevier. - 2352-1791. ; 18, s. 147-152
  • Tidskriftsartikel (refereegranskat)abstract
    • The impurity concentration in the tokamak divertor plasma is a necessary input for predictive scaling of divertor detachment, however direct measurements from existing tokamaks in different divertor plasma conditions are limited. To address this, we have applied a recently developed spectroscopic N II line ratio technique for measuring the N concentration in the divertor to a range of H-mode and L-mode plasma from the ASDEX Upgrade and JET tokamaks, respectively. The results from both devices show that as the power crossing the separatrix, P-sep, is increased under otherwise similar core conditions (e.g. density), a higher N concentration is required to achieve the same detachment state. For example, the N concentrations at the start of detachment increase from approximate to 2% to approximate to 9% as P-sep, is increased from approximate to 2.5 MW to approximate to 7 MW. These results tentatively agree with scaling law predictions (e.g. Goldston et al.) motivating a further study examining the parameters which affect the N concentration required to reach detachment. Finally, the N concentrations from spectroscopy and the ratio of D and N gas valve fluxes agree within experimental uncertainty only when the vessel surfaces are fully-loaded with N.
  •  
43.
  • Andresen, Louise C., et al. (författare)
  • Seasonal changes in nitrogen availability, and root and microbial uptake of (15)N(13)C(9)-phenylalanine and (15)N-ammonium in situ at a temperate heath
  • 2011
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 51, s. 94-101
  • Tidskriftsartikel (refereegranskat)abstract
    • In the plant biosynthesis of secondary compounds, phenylalanine is a precursor of condensed tannins. Tannins are deposited into the soil in plant root exudates and dead plant material and have been suggested to precipitate some soil nutrients and hence reduce nutrient availability for plants. Free amino acid, inorganic and microbial N concentration during the growing season was investigated in an ecosystem with a natural tannin chemosphere. The influence of tannins on the uptake of nitrogen in plants and microbes was followed by injecting tannic acid (TA), ammonium-(15)N and phenylalanine-(15)N/(13)C(9). Plants preferred ammonium over phenylalanine, while microbes had no preference. Soil microbes had a 77% uptake of intact phenylalanine. Phenylalanine was acquired intact by both grasses and Calluna, with 63% and 38% uptake of intact phenylalanine in grass fine roots and Calluna roots, respectively. Inorganic N and amino acid concentrations were lowest in the period with highest plant activity and grass root biomass but were unaffected by TA addition. (C) 2011 Elsevier B.V. All rights reserved.
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44.
  • Andresen, Louise C., et al. (författare)
  • Uptake of pulse injected nitrogen by soil microbes and mycorrhizal and non-mycorrhizal plants in a species-diverse subarctic heath ecosystem
  • 2008
  • Ingår i: Plant and Soil. - : Springer Science and Business Media LLC. - 0032-079X .- 1573-5036. ; 313:1-2, s. 283-295
  • Tidskriftsartikel (refereegranskat)abstract
    • N-15 labeled ammonium, glycine or glutamic acid was injected into subarctic heath soil in situ, with the purpose of investigating how the nitrogen added in these pulses was subsequently utilized and cycled in the ecosystem. We analyzed the acquisition of N-15 label in mycorrhizal and non-mycorrhizal plants and in soil microorganisms, in order to reveal probable differences in acquisition patterns between the two functional plant types and between plants and soil microorganisms. Three weeks after the label addition, with the N-15-forms added with same amount of nitrogen per square meter, we analyzed the N-15-enrichment in total soil, in soil K2SO4 (0.5 M) extracts and in the microbial biomass after vacuum-incubation of soil in chloroform and subsequent K2SO4 extraction. Furthermore the N-15-enrichment was analyzed in current years leaves of the dominant plant species sampled three, five and 21 days after label addition. The soil microorganisms had very high N-15 recovery from all the N sources compared to plants. Microorganisms incorporated most N-15 from the glutamic acid source, intermediate amounts of N-15 from the glycine source and least N-15 from the NH4+ source. In contrast to microorganisms, all ten investigated plant species generally acquired more N-15 label from the NH4+ source than from the amino acid sources. Non-mycorrhizal plant species showed higher concentration of N-15 label than mycorrhizal plant species 3 days after labeling, while 21 days after labeling their acquisition of N-15 label from amino acid injection was lower than, and the acquisition of N-15 label from NH4 injection was similar to that of the mycorrhizal species. We conclude that the soil microorganisms were more efficient than plants in acquiring pulses of nutrients which, under natural conditions, occur after e. g. freeze-thaw and dry rewet events, although of smaller size. It also appears that the mycorrhizal plants in the short term may be less efficient than non-mycorrhizal plants in nitrogen acquisition, but in a longer term show larger nitrogen acquisition than non-mycorrhizal plants. However, the differences in N-15 uptake patterns may also be due to differences in leaf longevity and woodiness between plant functional groups.
  •  
45.
  • Angioni, C., et al. (författare)
  • Dependence of the turbulent particle flux on hydrogen isotopes induced by collisionality
  • 2018
  • Ingår i: Physics of Plasmas. - : American Institute of Physics (AIP). - 1070-664X .- 1089-7674 .- 1070-6631 .- 1089-7666. ; 25:8
  • Tidskriftsartikel (refereegranskat)abstract
    • The impact of the change of the mass of hydrogen isotopes on the turbulent particle flux is studied. The trapped electron component of the turbulent particle convection induced by collisionality, which is outward in ion temperature gradient turbulence, increases with decreasing thermal velocity of the isotope. Thereby, the lighter is the isotope, the stronger is the turbulent pinch, and the larger is the predicted density gradient at the null of the particle flux. The passing particle component of the flux increases with decreasing mass of the isotope and can also affect the predicted density gradient. This effect is however subdominant for usual core plasma parameters. The analytical results are confirmed by means of both quasi-linear and nonlinear gyrokinetic simulations, and an estimate of the difference in local density gradient produced by this effect as a function of collisionality has been obtained for typical plasma parameters at mid-radius. Analysis of currently available experimental data from the JET and the ASDEX Upgrade tokamaks does not show any clear and general evidence of inconsistency with this theoretically predicted effect outside the errorbars and also allows the identification of cases providing weak evidence of qualitative consistency.
  •  
46.
  • Angioni, C., et al. (författare)
  • Gyrokinetic study of turbulent convection of heavy impurities in tokamak plasmas at comparable ion and electron heat fluxes
  • 2017
  • Ingår i: Nuclear Fusion. - : IOP PUBLISHING LTD. - 0029-5515 .- 1741-4326. ; 57:2
  • Tidskriftsartikel (refereegranskat)abstract
    • In tokamaks, the role of turbulent transport of heavy impurities, relative to that of neoclassical transport, increases with increasing size of the plasma, as clarified by means of general scalings, which use the ITER standard scenario parameters as reference, and by actual results from a selection of discharges from ASDEX Upgrade and JET. This motivates the theoretical investigation of the properties of the turbulent convection of heavy impurities by nonlinear gyrokinetic simulations in the experimentally relevant conditions of comparable ion and electron heat fluxes. These conditions also correspond to an intermediate regime between dominant ion temperature gradient turbulence and trapped electron mode turbulence. At moderate plasma toroidal rotation, the turbulent convection of heavy impurities, computed with nonlinear gyrokinetic simulations, is found to be directed outward, in contrast to that obtained by quasi-linear calculations based on the most unstable linear mode, which is directed inward. In this mixed turbulence regime, with comparable electron and ion heat fluxes, the nonlinear results of the impurity transport can be explained by the coexistence of both ion temperature gradient and trapped electron modes in the turbulent state, both contributing to the turbulent convection and diffusion of the impurity. The impact of toroidal rotation on the turbulent convection is also clarified.
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47.
  • Angioni, C., et al. (författare)
  • The impact of poloidal asymmetries on tungsten transport in the core of JET H-mode plasmas
  • 2015
  • Ingår i: Physics of Plasmas. - : AMER INST PHYSICS. - 1070-664X .- 1089-7674. ; 22:5
  • Tidskriftsartikel (refereegranskat)abstract
    • Recent progress in the understanding and prediction of the tungsten behaviour in the core of JET H-mode plasmas with ITER-like wall is presented. Particular emphasis is given to the impact of poloidal asymmetries of the impurity density. In particular, it is shown that the predicted reduction of temperature screening induced by the presence of low field side localization of the tungsten density produced by the centrifugal force is consistent with the observed tungsten behaviour in a JET discharge in H-mode baseline scenario. This provides first evidence of the role of poloidal asymmetries in reducing the strength of temperature screening. The main differences between plasma parameters in JET baseline and hybrid scenario discharges which affect the impact of poloidally asymmetric density on the tungsten radial transport are identified. This allows the conditions by which tungsten accumulation can be avoided to be more precisely defined.
  •  
48.
  • Appel, L. C., et al. (författare)
  • Equilibrium reconstruction in an iron core tokamak using a deterministic magnetisation model
  • 2018
  • Ingår i: Computer Physics Communications. - : ELSEVIER. - 0010-4655 .- 1879-2944. ; 223, s. 1-17
  • Tidskriftsartikel (refereegranskat)abstract
    • In many tokamaks ferromagnetic material, usually referred to as an iron-core, is present in order to improve the magnetic coupling between the solenoid and the plasma. The presence of the iron core in proximity to the plasma changes the magnetic topology with consequent effects on the magnetic field structure and the plasma boundary. This paper considers the problem of obtaining the free-boundary plasma equilibrium solution in the presence of ferromagnetic material based on measured constraints. The current approach employs, a model described by O'Brien et al. (1992) in which the magnetisation currents at the iron-air boundary are represented by a set of free parameters and appropriate boundary conditions are enforced via a set of quasi-measurements on the material boundary. This can lead to the possibility of overfitting the data and hiding underlying issues with the measured signals. Although the model typically achieves good fits to measured magnetic signals there are significant discrepancies in the inferred magnetic topology compared with other plasma diagnostic measurements that are independent of the magnetic field. An alternative approach for equilibrium reconstruction in iron-core tokamaks, termed the deterministic magnetisation model is developed and implemented in EFIT++. The iron is represented by a boundary current with the gradients in the magnetisation dipole state generating macroscopic internal magnetisation currents. A model for the boundary magnetisation currents at the iron-air interface is developed using B-Splines enabling continuity to arbitrary order; internal magnetisation currents are allocated to triangulated regions within the iron, and a method to enable adaptive refinement is implemented. The deterministic model has been validated by comparing it with a synthetic 2-D electromagnetic model of JET. It is established that the maximum field discrepancy is less than 1.5 mT throughout the vacuum region enclosing the plasma. The discrepancies of simulated magnetic probe signals are accurate to within 1% for signals with absolute magnitude greater than 100 mT; in all other cases agreement is to within 1 mT. The effect of neglecting the internal magnetisation currents increases the maximum discrepancy in the vacuum region to >20 mT, resulting in errors of 5%-10% in the simulated probe signals. The fact that the previous model neglects the internal magnetisation currents (and also has additional free parameters when fitting the measured data) makes it unsuitable for analysing data in the absence of plasma current. The discrepancy of the poloidal magnetic flux within the vacuum vessel is to within 0.1 Wb. Finally the deterministic model is applied to an equilibrium force-balance solution of a JET discharge using experimental data. It is shown that the discrepancies of the outboard separatrix position, and the outer strike-point position inferred from Thomson Scattering and Infrared camera data are much improved beyond the routine equilibrium reconstruction, whereas the discrepancy of the inner strike-point position is similar.
  •  
49.
  • Arnichand, H., et al. (författare)
  • Discriminating the trapped electron modes contribution in density fluctuation spectra
  • 2015
  • Ingår i: Nuclear Fusion. - : IOP PUBLISHING LTD. - 0029-5515 .- 1741-4326. ; 55:9
  • Tidskriftsartikel (refereegranskat)abstract
    • Quasi-coherent (QC) modes have been reported for more than 10 years in reflectometry fluctuations spectra in the core region of fusion plasmas. They have characteristics in-between coherent and broadband fluctuations as they oscillate at a marked frequency but have a wide spectrum. This work presents further evidences of the link recently established between QC modes and the trapped electron modes (TEM) instabilities (Arnichand et al 2014 Nucl. Fusion 54 123017). In electron cyclotron resonance heated discharges of Tore Supra, an enhancement of QC modes amplitude is observed in a region where TEM cause impurity transport and turbulence. In JET Ohmic plasmas, QC modes disappear during density ramp-up and current ramp-down. This is reminiscent of Tore Supra and TEXTOR observations during transitions from the linear Ohmic confinement (LOC) to the saturated Ohmic confinement (SOC) regimes. Evidencing TEM activity then becomes experimentally possible via analysis of fluctuation spectra.
  •  
50.
  • Aslanyan, V, et al. (författare)
  • Gyrokinetic simulations of toroidal Alfven eigenmodes excited by energetic ions and external antennas on the Joint European Torus
  • 2019
  • Ingår i: Nuclear Fusion. - : IOP PUBLISHING LTD. - 0029-5515 .- 1741-4326. ; 59:2
  • Tidskriftsartikel (refereegranskat)abstract
    • The gyrokinetic toroidal code (GTC) has been used to study toroidal Alfven eigenmodes (TAEs) in high-performance plasmas. Experiments performed at the Joint European Torus (JET), where TAEs were driven by energetic particles arising from neutral beams, ion cyclotron resonant heating, and resonantly excited by dedicated external antennas, have been simulated. Modes driven by populations of energetic particles are observed, matching the TAE frequency seen with magnetic probes in JET experiments. A synthetic antenna, composed of one toroidal and two neighboring poloidal harmonics has been used to probe the modes' damping rates and quantify mechanisms for this damping in GTC simulations. This method was also applied to frequency and damping rate measurements of stable TAEs made by the Alfven eigenmode active diagnostic in these discharges.
  •  
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