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- Lévy, L., et al.
(författare)
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Quantifying Reagent Spreading by Cross-Borehole Electrical Tomography to Assess Performance of Groundwater Remediation
- 2022
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Ingår i: Water Resources Research. - 0043-1397. ; 58:9
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Tidskriftsartikel (refereegranskat)abstract
- In situ remediation of contaminated groundwater often relies on the installation of a treatment zone (TZ) degrading the contamination. Zero-valent-iron (ZVI) is a type of reagent used for this purpose. Adequate delivery of ZVI in the whole target volume is particularly challenging and requires monitoring with high spatial resolution. We present a monitoring tool for imaging the dynamic spreading of ZVI and its associated ionic cloud, using cross-borehole time-lapse electrical resistivity tomography (ERT). This tool works in urban areas and is particularly suitable for achieving the required spatial resolution at the scale of the target volume. Groundwater and sediment samples show a consistent spatial and temporal distribution of the remediation cloud with cross-borehole ERT. Yet, the 2D anomalies observed with cross-borehole ERT provide a more spatially complete and rapid image of the remediation cloud distribution than if based solely on monitoring screens. At the study site, ZVI injection leads to uneven spreading, clearly documented by cross-borehole ERT monitoring. The benefit of hydraulic conductivity (K) mapping by cross-borehole induced polarization (IP) to understand unexpected injection paths (upstream leakage, spreading in preferred pathways) is investigated. A 2D, IP-based, continuous, and coherent K-distribution is obtained that compares well with estimations by grain size analyses from the TZ. However, the IP-based K-field fails at predicting injection paths, suggesting the creation of pathways during the high-pressure injection of ZVI. Cross-borehole time-lapse ERT is the most promising geophysical tool for performance assessment of in situ remediation involving reagents with conductivity contrast.
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| 3. |
- Bjerg, Anders, 1982, et al.
(författare)
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A population-based study of animal component sensitization, asthma, and rhinitis in schoolchildren
- 2015
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Ingår i: Pediatric Allergy and Immunology. - : Wiley. - 0905-6157 .- 1399-3038. ; 26:6, s. 557-563
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundAnimal sensitization is a major determinant of asthma in children. Component-resolved studies of unselected pediatric populations are lacking. The aim was to describe sensitization to animal components and the association with asthma and rhinitis in animal-sensitized schoolchildren. MethodsA random sample of 696 children (11-12years) from a Swedish population-based cohort was tested for sensitization to cat, dog, and horse dander using ImmunoCAP. Sera from animal-sensitized children were further analyzed by microarray including three allergen components from cat, four from dog, and two from horse. The parents completed an expanded ISAAC questionnaire. ResultsOf 259 animal-sensitized children (0.1 kU(A)/l), 51% were sensitized to all three, 23% to two, and 25% to one species. Current asthma and asthma symptoms following contact with cats were associated with co-sensitization to Fel d 1 and Fel d 4. This association was seen already at moderate-level sensitization (1-15 ISU) to Fel d 4, at which level most children were sensitized to Fel d 1, as well. In dog-sensitized children, the majority was sensitized to more than one dog component, and co-sensitization to Can f 5 and Can f 1/f 2 conferred the greatest risk for asthma. Sensitization to the highly cross-reactive serum albumins was uncommon and not associated with asthma. ConclusionsAmong schoolchildren in northern Sweden, where mite allergy is uncommon, furry animals were the primary perennial sensitizers. Asthma was associated with higher levels of component sensitization, and sensitization to more than one component from the same animal conferred the greatest risk.
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| 5. |
- Bjerg, L., et al.
(författare)
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Duration of diabetes-related complications and mortality in type 1 diabetes: a national cohort study
- 2021
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Ingår i: International Journal of Epidemiology. - : Oxford University Press (OUP). - 0300-5771 .- 1464-3685. ; 50:4, s. 1250-1259
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Tidskriftsartikel (refereegranskat)abstract
- Background: People with type 1 diabetes often live for many years with different combinations of diabetes-related complications. We aimed to quantify how complication duration and total complication burden affect mortality, using data from national registers. Methods: This study included 33 396 individuals with type 1 diabetes, registered in the Swedish National Diabetes Register at any time between 2001 and 2012. Each individual was followed and classified according to their time-updated diabetes-related complication status. The main outcomes were all-cause mortality, cardiovascular (CV) mortality and non-CV mortality. Poisson models were used to estimate the rate of these outcomes as a function of the time-updated complication duration. Results: Overall, 1748 of the 33 396 individuals died during 198 872 person-years of follow-up. Overall, the time-updated all-cause mortality rate ratio (MRR) was 2.25 [95% confidence interval (CI): 1.99-2.54] for patients with diabetic kidney disease, 0.98 (0.82-1.18) for patients with retinopathy and 4.00 (3.56-4.50) for patients with cardiovascular disease relative to individuals without complications. The excess rate was highest in the first period after a diagnosis of CVD, with an 8-fold higher mortality rate, and stabilized after some 5 years. After diagnosis of diabetic kidney disease, we observed an increase in all-cause mortality with an MRR of around 2 compared with individuals without diabetic kidney disease, which stabilized after few years. Conclusions: In this cohort we show that duration of diabetes-related complications is an important determinant of mortality in type 1 diabetes, for example the MRR associated with CVD is highest in the first period after diagnosis of CVD. A stronger focus on time-updated information and thorough consideration of complication duration may improve risk stratification in routine clinical practice.
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| 8. |
- Jonsson, Susanne, et al.
(författare)
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In situ degradation of monoethyl-, diethyl phthalate and o-phthalic acid in a landfil leachate plume (Grindsted, Denmark)
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The distribution of a-phthalic acid and ten of its mono- and diesters in the leachate plume downgradient of an unlined landfill (Grindsted, Denmark) was mapped along an 80 m transect. A total of 27 groundwater samples were concentrated by solid-phase extraction (SPE) using a polystyrene divinylbenzene (PS-DVB) polymer. Elevated concentrations of DEP, MEP and phthalic acid were observed, with maxima of 1260, 231 and 51 µg/L, respectively. Generally, high concentrations were observed close to the landfill border and in the lower parts of the aquifer. At a distance of 50m from the landfill border, the concentrations of all the studied phthalates, including DEP, MEP and PA, had decreased to below the detection limits (1 µg/L ). The presence of the specific metabolite MEP and PA, at the landfill border and in the plume, indicates that in situ anaerobic degradation/transformation of DEP occurred both in and beneath the landfill, as well as in the leachate-contarninated soil profile. Our findings suggest that anaerobic degradation is a key process also in the aquifer at the Grindsted landfill site. Tills study emphasises that phthalates should be regarded as potential contaminants in aquifers.
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| 10. |
- Rönmark, Eva, et al.
(författare)
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The Obstructive Lung Disease in Northern Sweden (OLIN) longitudinal paediatric study I : the first 10 years
- 2008
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Ingår i: Clinical Respiratory Journal. - Oxford : Blackwell Publishing. - 1752-6981 .- 1752-699X. ; 2:Suppl 1, s. 26-33
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Tidskriftsartikel (refereegranskat)abstract
- Background: Prospective studies of asthma and allergic conditions based oil the general population are scare.Aim: To summarize the methods and main results from a prospective study among school children.Methods: In 1996, a cohort of 3525 children aged 7/8 years in Northern Sweden were invited to a questionnaire survey using an expanded ISAAC protocol, and 97% participated. The cohort has been followed up yearly with high participation rate. Skin prick tests were conducted 1996, 2000 and 2006/2007. Allergens in dust from homes and schools have been analyzed. Sub samples have participated in interviews, lung function tests, bronchial hyper reactivity test, and analyses of IgE and IgG antibodies in serum.Results: The prevalence of asthma was 6% at age 7-8 years and increased by age. The incidence of physician-diagnosed asthma after the age of 7-8 years was around 1/100/year. The prevalence of positive skin prick test increased from 21% at age 7-8 to 30% at age 11-12 years. Remission of allergic sensitization was rare, while asthma remission was 5% yearly. The main risk factor for asthma and allergic sensitization increased in importance with increasing age. Allergic and non-allergic asthma had different risk factor pattern. Environmental risk factors decreased in impact after the age of 7. Avoidance of pets at home did not protect from asthma or allergic sensitization.Conclusion: The study includes important sources of data for further longitudinal analyses that will contribute to the understanding of the development and the nature of asthma and allergic sensitization.
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