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1.
  • Beck, Lisa J., et al. (författare)
  • Differing Mechanisms of New Particle Formation at Two Arctic Sites
  • 2021
  • Ingår i: Geophysical Research Letters. - 0094-8276 .- 1944-8007. ; 48:4
  • Tidskriftsartikel (refereegranskat)abstract
    • New particle formation in the Arctic atmosphere is an important source of aerosol particles. Understanding the processes of Arctic secondary aerosol formation is crucial due to their significant impact on cloud properties and therefore Arctic amplification. We observed the molecular formation of new particles from low-volatility vapors at two Arctic sites with differing surroundings. In Svalbard, sulfuric acid (SA) and methane sulfonic acid (MSA) contribute to the formation of secondary aerosol and to some extent to cloud condensation nuclei (CCN). This occurs via ion-induced nucleation of SA and NH3 and subsequent growth by mainly SA and MSA condensation during springtime and highly oxygenated organic molecules during summertime. By contrast, in an ice-covered region around Villum, we observed new particle formation driven by iodic acid but its concentration was insufficient to grow nucleated particles to CCN sizes. Our results provide new insight about sources and precursors of Arctic secondary aerosol particles.
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2.
  • Benavent, N., et al. (författare)
  • Substantial contribution of iodine to Arctic ozone destruction
  • 2022
  • Ingår i: Nature Geoscience. - : Springer Science and Business Media LLC. - 1752-0894 .- 1752-0908. ; 15, s. 770-773
  • Tidskriftsartikel (refereegranskat)abstract
    • Unlike bromine, the effect of iodine chemistry on the Arctic surface ozone budget is poorly constrained. We present ship-based measurements of halogen oxides in the high Arctic boundary layer from the sunlit period of March to October 2020 and show that iodine enhances springtime tropospheric ozone depletion. We find that chemical reactions between iodine and ozone are the second highest contributor to ozone loss over the study period, after ozone photolysis-initiated loss and ahead of bromine.
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3.
  • Christensen, T. R., et al. (författare)
  • Multiple Ecosystem Effects of Extreme Weather Events in the Arctic
  • 2021
  • Ingår i: Ecosystems. - : Springer Science and Business Media LLC. - 1432-9840 .- 1435-0629. ; 24:1, s. 122-136
  • Tidskriftsartikel (refereegranskat)abstract
    • The Arctic is getting warmer and wetter. Here, we document two independent examples of how associated extreme precipitation patterns have severe implications for high Arctic ecosystems. The events stand out in a 23-year record of continuous observations of a wide range of ecosystem parameters and act as an early indication of conditions projected to increase in the future. In NE Greenland, August 2015, one-quarter of the average annual precipitation fell during a 9-day intensive rain event. This ranked number one for daily sums during the 1996–2018 period and caused a strong and prolonged reduction in solar radiation decreasing CO2 uptake in the order of 18–23 g C m−2, a reduction comparable to typical annual C budgets in Arctic tundra. In a different type of event, but also due to changed weather patterns, an extreme snow melt season in 2018 triggered a dramatic gully thermokarst causing rapid transformation in ecosystem functioning from consistent annual ecosystem CO2 uptake and low methane exchange to highly elevated methane release, net source of CO2, and substantial export of organic carbon downstream as riverine and coastal input. In addition to climate warming alone, more frequent occurrence of extreme weather patterns will have large implications for otherwise undisturbed tundra ecosystems including their element transport and carbon interactions with the atmosphere and ocean.
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4.
  • Petäjä, Tuukka, et al. (författare)
  • Overview : Integrative and Comprehensive Understanding on Polar Environments (iCUPE) - concept and initial results
  • 2020
  • Ingår i: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 20:14, s. 8551-8592
  • Tidskriftsartikel (refereegranskat)abstract
    • The role of polar regions is increasing in terms of megatrends such as globalization, new transport routes, demography, and the use of natural resources with consequent effects on regional and transported pollutant concentrations. We set up the ERA-PLANET Strand 4 project iCUPE - integrative and Comprehensive Understanding on Polar Environments to provide novel insights and observational data on global grand challenges with an Arctic focus. We utilize an integrated approach combining in situ observations, satellite remote sensing Earth observations (EOs), and multi-scale modeling to synthesize data from comprehensive long-term measurements, intensive campaigns, and satellites to deliver data products, metrics, and indicators to stakeholders concerning the environmental status, availability, and extraction of natural resources in the polar areas. The iCUPE work consists of thematic state-of-the-art research and the provision of novel data in atmospheric pollution, local sources and transboundary transport, the characterization of arctic surfaces and their changes, an assessment of the concentrations and impacts of heavy metals and persistent organic pollutants and their cycling, the quantification of emissions from natural resource extraction, and the validation and optimization of satellite Earth observation (EO) data streams. In this paper we introduce the iCUPE project and summarize initial results arising out of the integration of comprehensive in situ observations, satellite remote sensing, and multi-scale modeling in the Arctic context.
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5.
  • Weinreich, I. D., et al. (författare)
  • Scandiatransplant Exchange Program (STEP): Development and Results From an International Kidney Exchange Program
  • 2023
  • Ingår i: Transplantation Direct. - 2373-8731. ; 9:11
  • Tidskriftsartikel (refereegranskat)abstract
    • Background. Kidney transplant candidates may be incompatible with their intended living donors because of the presence of antibodies against HLA and/or ABO. To increase the possibility of finding an acceptable kidney donor for these patients, the Scandiatransplant Exchange Program (STEP) program within Scandiatransplant was launched in 2019.Methods. This is a retrospective review of our experiences from the first 4 y of the STEP program, including details about the match runs, performed transplantations, and recipient outcomes within the program.Results. During 2019-2022, 11 match runs and 4 reruns were performed. In total, 114 pairs and 6 anonymous donors participated in these match runs. Fifty-one pairs (45%) participated in 1 match run, 31 pairs (27%) participated in 2 match runs, and 32 pairs (29%) participated in >= 3 match runs. Seventy-two individuals (63%) participated because of HLA incompatibility, 19 (17%) because of ABO incompatibility, and 7 (6%) because of both HLA and ABO incompatibility. Forty percent of the patients enrolled in the program underwent transplantation. In total, 49 transplantations have so far been performed within the program, and 46 (94%) of the recipients had a functioning kidney graft at follow-up in February 2023.Results. During 2019-2022, 11 match runs and 4 reruns were performed. In total, 114 pairs and 6 anonymous donors participated in these match runs. Fifty-one pairs (45%) participated in 1 match run, 31 pairs (27%) participated in 2 match runs, and 32 pairs (29%) participated in >= 3 match runs. Seventy-two individuals (63%) participated because of HLA incompatibility, 19 (17%) because of ABO incompatibility, and 7 (6%) because of both HLA and ABO incompatibility. Forty percent of the patients enrolled in the program underwent transplantation. In total, 49 transplantations have so far been performed within the program, and 46 (94%) of the recipients had a functioning kidney graft at follow-up in February 2023.Conclusions. The STEP program offers sensitized patients an enlarged pool of living donors and a chance of a compatible international living donor, resulting in an increased number of total transplantations. Currently, STEP is one of the largest transnational kidney exchange programs and has improved the situation for patients waiting for kidney transplantation in Scandiatransplant.
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6.
  • Balieva, F. N., et al. (författare)
  • Treatment Preferences in Young Adults with Moderate to Severe Psoriasis: A Qualitative Study from the Nordic Countries
  • 2023
  • Ingår i: Dermatology and Therapy. - 2193-8210. ; 13:8, s. 1873-1887
  • Tidskriftsartikel (refereegranskat)abstract
    • IntroductionThe purpose of this study is to explore treatment preferences and identify patient characteristics in young bio-naive adults with moderate to severe psoriasis in the Nordic countries (Norway, Finland, Sweden, and Denmark).MethodsPatients were 18-45 years old and bio-naive but referred for biologic treatment of moderate to severe psoriasis. Patients were included at eight Nordic dermatology clinics. Patients with significant comorbidity or psoriatic arthritis were excluded. The Psoriasis Area and Severity Index (PASI) and Dermatology Life Quality Index (DLQI) were assessed along with basic patient information.A semistructured interview guide was used in individual qualitative interviews, asking patients about their treatment preferences and reasons, disease journey, and disease management. The interviews were analyzed using thematic content analysis. Twenty-four patients sufficed to reach saturation in this qualitative study.ResultsThe patient sample characteristics represented a qualitative variation in age, sex, symptoms, duration of disease, and country. We included a total of 12 male and 12 female patients. The mean age was 34 years (range 18-45 years), the mean age at diagnosis was 20 years (range 6-34 years), the mean & PLUSMN; standard deviation (SD) time since diagnosis was 13 & PLUSMN; 8 years, PASI was 9.5 & PLUSMN; 4.7, and DLQI was 15.2 & PLUSMN; 6.4.Interviews suggested that both the burden of disease as well as the burden of treatment influenced patient preferences regarding treatment attributes, hence getting alleviation from symptoms did not alone influence patient preferences. Time, effort, and inconvenience related to psoriasis treatments also influenced patient preferences.ConclusionsThis first in-depth, qualitative study in young bio-naive adults with psoriasis suggests that patient preferences are focusing not only on symptom relief but also on alleviating the burden of psoriasis treatment. Understanding the reasons for patient preferences and the perspectives of young adults is needed to guide individual shared decision-making in psoriasis management. Plain Language SummaryNot much research has been done on understanding the disease burden and treatment needs of young adults suffering from psoriasis. This is an interview study with young adults from Nordic countries suffering from moderate to severe psoriasis with an active lifestyle. The adult patients were all referred for biologic treatment of psoriasis but had not yet started treatment when they were interviewed. The aim was to explore treatment preferences in this group.The study showed that treatment goals depended upon both alleviation of symptoms and obtaining a low treatment burden. The most influential symptoms were scaling, itching, and visible plaques. The most important treatment burden features were efficacy, durability, speed of response, safety, and convenience. Understanding the reasons behind these different treatment preferences is essential to help shared-decision psoriasis management that matches individual needs.
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7.
  • Ekberg, Jana, 1964, et al. (författare)
  • A Randomized Controlled Trial on Safety of Steroid Avoidance in Immunologically Low-Risk Kidney Transplant Recipients
  • 2022
  • Ingår i: Kidney International Reports. - : Elsevier BV. - 2468-0249. ; 7:2, s. 259-269
  • Tidskriftsartikel (refereegranskat)abstract
    • Introduction: Steroid-based immunosuppression after transplantation increases the risk of post-transplant diabetes mellitus (PTDM), with adverse effects on patient and graft survival. In the SAILOR study, we investigated the safety and efficacy of complete steroid avoidance in immunologically low-risk kidney recipients without diabetes on the current standard-of-care maintenance regimen with tacrolimus/mycophenolate mofetil (MMF). Methods: In this 2-year, multicenter, open-label trial, a total of 222 patients were randomized to receive either steroid avoidance protocol (tacrolimus/MMF/antithymocyte globulin [ATG] induction [n = 113]) or steroid maintenance protocol (tacrolimus/MMF/prednisolone/basiliximab-induction [n = 109]). Results: At 1 year, no significant differences were found between steroid avoidance and steroid maintenance arms in the incidence of PTDM, the primary end point (12.4% vs. 18.3%, respectively, P = 0.30, CI: 16.3–4.4), or in overall biopsy-proven rejections (15% vs. 13.8%, respectively, P = 0.85). At 2 years, the composite end point of freedom from acute rejection, graft loss, and death (81% vs. 85%, respectively, P = 0.4), kidney function, or adverse events was comparable between the 2 arms. Moreover, 63.9% of the patients in the steroid avoidance arm remained free from steroids at 2 years. Conclusion: The SAILOR study provides further evidence for the feasibility, safety, and efficacy of early steroid-free treatment at 2 years in immunologically low-risk kidney recipients with tacrolimus/MMF maintenance regimen. © 2021 International Society of Nephrology
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8.
  • Hesse, M., et al. (författare)
  • The predictive value of brief measures of externalizing behavior and internalizing problems in young people receiving substance use treatment : A secondary analysis
  • 2023
  • Ingår i: Addictive Behaviours. - : Elsevier Ltd. - 0306-4603 .- 1873-6327. ; 139
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Identifying people at risk of poor outcomes following treatment for substance use disorders is important for developing tailored services. The aim of this study was to test whether a brief measure of internalizing and externalizing behavior could identify young adults at high risk of psychiatric care episodes and criminal offending up to four years after enrolment in treatment for substance use disorder. Methods: Clients aged 15–25 years from a randomized multicenter study were included (N = 457). At baseline, all completed the YouthMap12 screener, a measure of internalizing symptoms (IP6) and externalizing problems (EP6). We used accelerated failure time regression to assess time to psychiatric care and criminal offending, adjusting for baseline occurrence, gender, age, treatment group, and uptake area. Youden's J was used to assess optimal cut-points for risk of events. Results: The IP6 was associated with shorter time to psychiatric care following treatment enrolment (beta = −0.71, 95% confidence interval [CI] = −0.94 to −0.48; adjusted beta = −0.45, 95% CI = −0.66 to −0.25). The EP6 was associated with shorter time to criminal offending, coefficient = −0.32, 95% CI = −0.44 to −0.19; adjusted coefficient = −0.18, 95% CI = −0.30 to −0.06). Optimal cut-points were two or more for the IP6 and three or more for the EP6. Conclusions: The IP6 and the EP6, two simple and easily administered instruments, can identify young adults who are at an increased risk of future criminal offending or in need of psychiatric care. The findings lend support to using the 12-item YouthMap, as it identifies relevant risks, is compatible with local service delivery needs, and is theoretically and empirically supported. © 2022 The Author(s)
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9.
  • Nøjgaard, J. K., et al. (författare)
  • A local marine source of atmospheric particles in the High Arctic
  • 2022
  • Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310. ; 285
  • Tidskriftsartikel (refereegranskat)abstract
    • The chemical composition of non-refractory submicron aerosol (NR-PM1) was characterized at the Villum Research Station (Villum) at Station Nord in North Greenland during spring-summer 2016 using a Time of Flight Aerosol Chemical Speciation Monitor (ToF-ACSM). The composition is dominated by sulfate (48%) and organic species (40%). Positive Matrix Factorization (PMF) identified three key factors corresponding to a primary hydrocarbon-like organic aerosol (HOA), and two types of secondary organic aerosol: oxygenated organic aerosol (OOA) and a marine organic aerosol (MOA). The HOA factor accounts for 5% of the organic aerosol mass, which is consistent with previous findings at Villum. The OOA factor accounts for 77% of the organic aerosol mass and correlates with accumulation mode particles, which supports previous findings indicating that oxidized organic aerosols are predominantly from long-range transport during winter and spring at Villum. The MOA factor was characterized by mass spectral fragments of methane sulfonic acid (MSA) from atmospheric oxidation of dimethyl sulfide, for which reason the MOA factor is considered to be of biogenic origin. MOA accounts for 18% of the organic aerosol mass and correlates with locally produced Aitken mode particles. This indicates that biogenic processes are not only a significant source of aerosols at Villum, but MOA also appears to be formed in the vicinity of the measurement site. This local geographical origin was confirmed through air mass back trajectory modelling and source-receptor analysis. During May, air masses frequently arrived from the east, with source regions for the MOA factor and therewith MSA located in the Barents Sea and Lincoln Sea with lesser contributions from the Greenland Sea. During June, air mass origin shifted to the west, with source regions for the MOA factor and MSA shifting correspondingly to Baffin Bay and the Canadian Arctic Archipelago. While shifting transport patterns between May and June lead to shifting source regions, sea ice likely played a role as well. During May, marginal ice zones were present in the Barents Sea between Svalbard and Franz Josef Land, while during June, sea ice in the northern part of Baffin Bay retreated and sea ice in the Canadian Arctic Archipelago decreased. Although May and June experienced different transport patterns and sea ice conditions, levels of the MOA factor and MSA were similar between the months. This is likely due to similarities between marine biological activities in the Barents Sea and Baffin Bay. This research highlights the complex relationship between transport patterns, sea ice conditions, and atmospheric particle concentrations. Multiyear aerosol chemical composition from several High Arctic sites is encouraged to determine the full effects of ocean-atmosphere interactions and transport patterns on atmospheric aerosol concentrations.
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10.
  • Sahin, Cagla, et al. (författare)
  • Structural Basis for Dityrosine-Mediated Inhibition of α-Synuclein Fibrillization
  • 2022
  • Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 144:27, s. 11949-11954
  • Tidskriftsartikel (refereegranskat)abstract
    • α-Synuclein (α-Syn) is an intrinsically disordered protein which self-assembles into highly organized β-sheet structures that accumulate in plaques in brains of Parkinson’s disease patients. Oxidative stress influences α-Syn structure and self-assembly; however, the basis for this remains unclear. Here we characterize the chemical and physical effects of mild oxidation on monomeric α-Syn and its aggregation. Using a combination of biophysical methods, small-angle X-ray scattering, and native ion mobility mass spectrometry, we find that oxidation leads to formation of intramolecular dityrosine cross-linkages and a compaction of the α-Syn monomer by a factor of √2. Oxidation-induced compaction is shown to inhibit ordered self-assembly and amyloid formation by steric hindrance, suggesting an important role of mild oxidation in preventing amyloid formation.
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11.
  • Sandvik, R. M., et al. (författare)
  • Contemporary N-2 and SF6 multiple breath washout in infants and toddlers with cystic fibrosis
  • 2022
  • Ingår i: Pediatric Pulmonology. - : Wiley. - 8755-6863 .- 1099-0496.
  • Tidskriftsartikel (refereegranskat)abstract
    • Introduction Multiple breath washout (MBW) is used for early detection of cystic fibrosis (CF) lung disease, with SF6MBW commonly viewed as the reference method. The use of N2MBW in infants and toddlers has been questioned for technical and physiological reasons, but a new correction of the N(2 )signal has minimized the technical part. The present study aimed to assess the remaining differences and the contributing mechanisms for the differences between SF6 and N2MBW,corrected-such as tidal volume reduction during N-2 washout with pure O-2. Method This was a longitudinal multicenter cohort study. SF6MBW and N2MBW were performed prospectively at three CF centers in the same visits on 154 test occasions across 62 children with CF (mean age: 22.7 months). Offline analysis using identical algorithms to the commercially available program provided outcomes of N-2,N-original and N-2,N-corrected for comparison with SF6MBW. Results Mean functional residual capacity, FRCN2,corrected was 14.3% lower than FRCN2, original, and 1.0% different from FRCSF6. Lung clearance index, LCIN2,corrected was 25.2% lower than LCIN2,original, and 7.3% higher than LCISF6. Mean (SD) tidal volume decreased significantly during N2MBWcorrected, compared to SF6MBW (-13.1 ml [-30.7; 4.6], p < 0.0001, equal to -12.0% [-25.7; 1.73]), but this tidal volume reduction did not correlate to the differences between LCIN2,corrected and LCISF6. The absolute differences in LCI increased significantly with higher LCISF6 (0.63/LCISF6) and (0.23/LCISF6), respectively, for N-2,N-original and N-2,N-corrected, but the relative differences were stable across disease severity for N-2,N-corrected, but not for N-2,N-original. Conclusion Only minor residual differences between FRCN2,corrected and FRCSF6 remained to show that the two methods measure gas volumes very similar in this age range. Small differences in LCI were found. Tidal volume reduction during N2MBW did not affect differences. The corrected N2MBW can now be used with confidence in young children with CF, although not interchangeably with SF6.
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12.
  • Sandvik, R. M., et al. (författare)
  • Nationwide lung function monitoring from infancy in newborn-screened children with cystic fibrosis
  • 2023
  • Ingår i: European Respiratory Journal Open Research (ERJ Open Research). - 2312-0541. ; 9:5
  • Tidskriftsartikel (refereegranskat)abstract
    • Background Cystic fibrosis (CF) lung disease starts in infancy and can be assessed for structural lung abnormalities using computed tomography or magnetic resonance scans, or for lung function impairment using multiple breath washout (MBW). However, in infancy these two methods are not well correlated. Trajectories of CF lung disease assessed by MBW in infants and toddlers remain poorly described, which is why we aimed to 1) describe the trajectory of lung function, 2) explore risk factors for progression and 3) explore the real-life effect of lumacaftor/ivacaftor. Methods This was a nationwide observational cohort study (2018-2021) using data collected as part of the routine clinical surveillance programme (including MBW and monthly endo-laryngeal suction sampling for bacterial pathogens) in children born after implementation of newborn screening for CF (May 2016). Lumacaftor/ivacaftor commenced from age 2 years in children homozygous for F508del. Ventilation distribution efficiency (VDE), recently described to have advantages over lung clearance index (LCI), was reported as the primary MBW outcome after z-score calculations based on published reference data. Mixed effect linear regression models were the main statistical analyses performed in this study. Results 59 children, aged 2-45 months, contributed with 211 MBW occasions (median (interquartile range (IQR)) 3 (2-5) MBW occasions per child) with a median (IQR) follow-up time of 10.8 (5.222.3) months. An overall mean annual deterioration rate of -0.50 (95% CI -0.78-0.22) z-VDE was observed, starting from an estimated mean z-VDE of -1.68 (95% CI -2.15-1.22) at age 0.0 years (intercept). Pseudomonas aeruginosa "ever" (n=14, MBWs 50) had a significantly worse z-VDE trajectory versus P. aeruginosa "never" (mean difference 0.53 (95% CI 0.16-0.89) per year; p=0.0047) and lumacaftor/ivacaftor treatment (n=22, MBWs 46) significantly improved the trajectory of z-VDE (mean difference 1.72 (95% CI 0.79-2.66) per year; p=0.0004), leading to a stable mean z-VDE trajectory after start of treatment. Conclusions Infants and toddlers with CF demonstrated progressive deterioration in z-VDE over the first years of life. P. aeruginosa isolation "ever" was associated with an accelerated deterioration in lung function, while lumacaftor/ivacaftor therapy significantly improved and stabilised the trajectory.
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13.
  • Schmale, Julia, et al. (författare)
  • Pan-Arctic seasonal cycles and long-term trends of aerosol properties from 10 observatories
  • 2022
  • Ingår i: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 22:5, s. 3067-3096
  • Tidskriftsartikel (refereegranskat)abstract
    • Even though the Arctic is remote, aerosol properties observed there are strongly influenced by anthropogenic emissions from outside the Arctic. This is particularly true for the so-called Arctic haze season (January through April). In summer (June through September), when atmospheric transport patterns change, and precipitation is more frequent, local Arctic sources, i.e., natural sources of aerosols and precursors, play an important role. Over the last few decades, significant reductions in anthropogenic emissions have taken place. At the same time a large body of literature shows evidence that the Arctic is undergoing fundamental environmental changes due to climate forcing, leading to enhanced emissions by natural processes that may impact aerosol properties.In this study, we analyze 9 aerosol chemical species and 4 particle optical properties from 10 Arctic observatories (Alert, Kevo, Pallas, Summit, Thule, Tiksi, Barrow/Utqiaġvik, Villum, and Gruvebadet and Zeppelin Observatory – both at Ny-Ålesund Research Station) to understand changes in anthropogenic and natural aerosol contributions. Variables include equivalent black carbon, particulate sulfate, nitrate, ammonium, methanesulfonic acid, sodium, iron, calcium and potassium, as well as scattering and absorption coefficients, single scattering albedo and scattering Ångström exponent.First, annual cycles are investigated, which despite anthropogenic emission reductions still show the Arctic haze phenomenon. Second, long-term trends are studied using the Mann–Kendall Theil–Sen slope method. We find in total 41 significant trends over full station records, i.e., spanning more than a decade, compared to 26 significant decadal trends. The majority of significantly declining trends is from anthropogenic tracers and occurred during the haze period, driven by emission changes between 1990 and 2000. For the summer period, no uniform picture of trends has emerged. Twenty-six percent of trends, i.e., 19 out of 73, are significant, and of those 5 are positive and 14 are negative. Negative trends include not only anthropogenic tracers such as equivalent black carbon at Kevo, but also natural indicators such as methanesulfonic acid and non-sea-salt calcium at Alert. Positive trends are observed for sulfate at Gruvebadet.No clear evidence of a significant change in the natural aerosol contribution can be observed yet. However, testing the sensitivity of the Mann–Kendall Theil–Sen method, we find that monotonic changes of around 5 % yr−1 in an aerosol property are needed to detect a significant trend within one decade. This highlights that long-term efforts well beyond a decade are needed to capture smaller changes. It is particularly important to understand the ongoing natural changes in the Arctic, where interannual variability can be high, such as with forest fire emissions and their influence on the aerosol population.To investigate the climate-change-induced influence on the aerosol population and the resulting climate feedback, long-term observations of tracers more specific to natural sources are needed, as well as of particle microphysical properties such as size distributions, which can be used to identify changes in particle populations which are not well captured by mass-oriented methods such as bulk chemical composition.
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14.
  • Skov, Jakob, et al. (författare)
  • Co-aggregation and heritability of organ-specific autoimmunity : a population-based twin study
  • 2020
  • Ingår i: European Journal of Endocrinology. - : Bioscientifica. - 0804-4643 .- 1479-683X. ; 182:5, s. 473-480
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective: Co-aggregation of autoimmune diseases is common, suggesting partly shared etiologies. Genetic factors are believed to be important, but objective measures of environ mental vs heritable influences on co-aggregation are absent. With a novel approach to twin studies, we aimed at estimating heritability and genetic overlap in seven organspecific autoimmune diseases.Design: Prospective twin cohort study.Methods: We used a cohort of 110 814 twins to examine co-aggregation and heritability of Hashimoto's thyroiditis, atrophic gastritis, celiac disease, Graves' disease, type 1 diabetes, vitiligo and Addison's disease. Hazard ratios (HR) were calculated for twins developing the same or different disease as compared to their co-twin. The differences between monozygotic and dizygotic twin pairs were used to estimate the genetic influence on co-aggregation. Heritability for individual disorders was calculated using structural equational modeling adjusting for censoring and truncation of data.Results: Co-aggregation was more pronounced in monozygotic twins (media n HR: 3.2, range: 2.2-9.2) than in dizygotic twins (median HR: 2.4, range: 1.1-10.0). Heritability was moderate for atrophic gastritis (0.38, 95% CI: 0.23-0.53) but high for all other diseases, ranging from 0.60 (95% CI: 0.49-0. 71) for Graves' disease to 0.97 (95% CI: 0.91- 1.00) for Addison's disease.Conclusions: Overall, co-aggregation was more pronounced in monozygotic than in dizygotic twins, suggesting that disease overlap is largely attributable to genetic factors. Co-aggregation was common, and twins faced up to a ten-fold risk of developing diseases not present in their co-twin. Our results validate and refine previous heritability estimates based on smaller twin cohorts.
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15.
  • Skov, J., et al. (författare)
  • Co-aggregation and heritability of organ-specific autoimmunity: a population-based twin study
  • 2020
  • Ingår i: European Journal of Endocrinology. - : Oxford University Press (OUP). - 0804-4643 .- 1479-683X. ; 182:5, s. 473-480
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective: Co-aggregation of autoimmune diseases is common, suggesting pa rtly shared etiologies. Genetic factors are believed to be important, but objective measures of environ mental vs heritable influences on co-aggregation are absent. With a novel approach to twin studies, we aimed at esti mating heritability and genetic overlap in seven organspecific autoimmune diseases. Design: Prospective twin cohort study. Methods: We used a cohort of 110 814 twins to examine co-aggregation an d heritability of Hashimoto's thyroiditis, atrophic gastritis, celiac disease, Graves' disease, type 1 dia betes, vitiligo and Addison's disease. Hazard ratios (HR) were calculated for twins developing the same or different disea se as compared to their co-twin. The differences between monozygotic and dizygotic twin pairs were used to estim ate the genetic influence on co- aggregation. Heritability for individual disorders was calculated using stru ctural equational modeling adjusting for censoring and truncation of data. Results: Co-aggregation was more pronounced in monozygotic twins (media n HR: 3.2, range: 2.2-9.2) than in dizygotic twins (median HR: 2.4, range: 1.1-10.0). Heritability was moder ate for atrophic gastritis (0.38, 95% CI: 0.23-0.53) but high for all other diseases, ranging from 0.60 (95% CI: 0.49-0. 71) for Graves' disease to 0.97 (95% CI: 0.91- 1.00) for Addison's disease. Conclusions: Overall, co-aggregation was more pronounced in monozygotic tha n in dizygotic twins, suggesting that disease overlap is largely attributable to genetic factors. Co- aggregation was common, and twins faced up to a ten-fold risk of developing diseases not present in their co-twin. Our r esults validate and refine previous heritability estimates based on smaller twin cohorts.
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16.
  • Skov, J., et al. (författare)
  • Shared etiology of type 1 diabetes and Hashimoto's thyroiditis: a population-based twin study
  • 2022
  • Ingår i: European Journal of Endocrinology. - : Oxford University Press (OUP). - 0804-4643 .- 1479-683X. ; 186:6, s. 677-685
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective: Type 1 diabetes and Hashimoto's thyroiditis frequently cluster in individuals and in families, indicating shared origins. The objective of this study was to investigate familial co-aggregation of these diseases and to quantify shared genetic and environmental factors. Design: This study is a twin cohort study. Methods: National health registers were used to identify cases among 110 814 Swedish twins. Co-aggregation was calculated as risk ratios for type 1 diabetes among co-twins of individuals with Hashimoto's thyroiditis, and vice-versa. Variance explained by genetics (i.e. heritability), and the proportions thereof shared between the diseases, was estimated by contrasting associations in monozygotic and dizygotic twins using structural equation models. Results: Individuals with one disease were at a high risk for the other disease (adjusted risk ratio: 11.4 (95% CI: 8.5-15.3)). Co-aggregation was more common in monozygotic than in dizygotic pairs, with adjusted risk ratios of 7.0 (95% CI: 3.2-15.1) and 1.7 (95% CI: 0.7-4.1), respectively. Genetic effects shared across diseases accounted for 11% of the variance for type 1 diabetes and 9% of the variance for Hashimoto's thyroiditis, while environmental factors unique to individual twins, but shared across diseases, accounted for 10% of the variance for type 1 diabetes and 18% of the variance for Hashimoto's thyroiditis. Conclusions: Both genes and environment unique to individual twins contribute to considerable etiologic overlap between type 1 diabetes and Hashimoto's thyroiditis. These findings add to the current knowledge on the mechanisms behind autoimmune disease clustering and could guide future research aimed at identifying pathophysiological mechanisms and intervention targets.
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17.
  • Sze, K. C. H., et al. (författare)
  • Ice-nucleating particles in northern Greenland: annual cycles, biological contribution and parameterizations
  • 2023
  • Ingår i: Atmospheric Chemistry and Physics. - 1680-7316. ; 23:8, s. 4741-4761
  • Tidskriftsartikel (refereegranskat)abstract
    • Ice-nucleating particles (INPs) can initiate ice formation in clouds at temperatures above - 38 C-? through heterogeneous ice nucleation. As a result, INPs affect cloud microphysical and radiative properties, cloud lifetime, and precipitation behavior and thereby ultimately the Earth's climate. Yet, little is known regarding the sources, abundance and properties of INPs, especially in remote regions such as the Arctic. In this study, 2 -yearlong INP measurements (from July 2018 to September 2020) at Villum Research Station in northern Greenland are presented. A low-volume filter sampler was deployed to collect filter samples for offline INP analysis. An annual cycle of INP concentration (NINP) was observed, and the fraction of heat-labile INPs was found to be higher in months with low to no snow cover and lower in months when the surface was well covered in snow (> 0.8 m). Samples were categorized into three different types based only on the slope of their INP spectra, namely into summer, winter and mix type. For each of the types a temperature-dependent INP parameterization was derived, clearly different depending on the time of the year. Winter and summer types occurred only during their respective seasons and were seen 60 % of the time. The mixed type occurred in the remaining 40 % of the time throughout the year. April, May and November were found to be transition months. A case study comparing April 2019 and April 2020 was performed. The month of April was selected because a significant difference in NINP was observed during these two periods, with clearly higher NINP in April 2020. In parallel to the observed differences in NINP, also a higher cloud-ice fraction was observed in satellite data for April 2020, compared to April 2019. NINP in the case study period revealed no clear dependency on either meteorological parameters or different surface types which were passed by the collected air masses. Overall, the results suggest that the coastal regions of Greenland were the main sources of INPs in April 2019 and 2020, most likely including both local terrestrial and marine sources.
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