| 1. |
- Sourander, Birger, et al.
(författare)
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No effect of remdesivir or betamethasone on upper respiratory tract SARS-CoV-2 RNA kinetics in hospitalised COVID-19 patients: a retrospective observational study
- 2022
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Ingår i: Infectious Diseases. - : Informa UK Limited. - 2374-4235 .- 2374-4243. ; 54:10, s. 703-712
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Tidskriftsartikel (refereegranskat)abstract
- Background The viral kinetics of SARS-CoV-2 has been considered clinically important. While remdesivir and corticosteroids are recommended for COVID-19 patients requiring oxygen support, there is a limited number of published reports on viral kinetics in hospitalised patients with COVID-19 treated with remdesivir or corticosteroids. Methods We conducted a retrospective study by collecting longitudinal samples from the nasopharynx/throat of 123 hospitalised patients (median age 55 years, 74% male) with COVID-19, to evaluate the effects of remdesivir and corticosteroid treatment on viral RNA levels. The subjects were divided into four groups: those receiving remdesivir (n = 25), betamethasone (n = 41), both (n = 15), or neither (n = 42). Time to viral RNA clearance was analysed using Kaplan-Meier plots, categorical data were analysed using Fisher's exact test, and Kruskal-Wallis for continuous data. Viral RNA decline rate was analysed using a mixed effect model. Results We found no significant difference in SARS-CoV-2 RNA decline rate or time to SARS-CoV-2 RNA clearance between the groups. Moreover, clinical status at baseline was not correlated with time to viral clearance. Conclusions Since SARS-CoV-2 RNA kinetics was not affected by treatment, repeated sampling from the upper respiratory tract cannot be used to evaluate treatment response.
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| 2. |
- Marklund, Emelie, et al.
(författare)
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Serum-IgG responses to SARS-CoV-2 after mild and severe COVID-19 infection and analysis of IgG non-responders.
- 2020
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Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 15:10
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Tidskriftsartikel (refereegranskat)abstract
- To accurately interpret COVID-19 seroprevalence surveys, knowledge of serum-IgG responses to SARS-CoV-2 with a better understanding of patients who do not seroconvert, is imperative. This study aimed to describe serum-IgG responses to SARS-CoV-2 in a cohort of patients with both severe and mild COVID-19, including extended studies of patients who remained seronegative more than 90 days post symptom onset.SARS-CoV-2-specific IgG antibody levels were quantified using two clinically validated and widely used commercial serological assays (Architect, Abbott Laboratories and iFlash 1800, YHLO), detecting antibodies against the spike and nucleocapsid proteins.Forty-seven patients (mean age 49 years, 38% female) were included. All (15/15) patients with severe symptoms and 29/32 (90.6%) patients with mild symptoms of COVID-19 developed SARS-CoV-2-specific IgG antibodies in serum. Time to seroconversion was significantly shorter (median 11 vs. 22 days, P = 0.04) in patients with severe compared to mild symptoms. Of the three patients without detectable IgG-responses after >90 days, all had detectable virus-neutralizing antibodies and in two, spike-protein receptor binding domain-specific IgG was detected with an in-house assay. Antibody titers were preserved during follow-up and all patients who seroconverted, irrespective of the severity of symptoms, still had detectable IgG levels >75 days post symptom onset.Patients with severe COVID-19 both seroconvert earlier and develop higher concentrations of SARS-CoV-2-specific IgG than patients with mild symptoms. Of those patients who not develop detectable IgG antibodies, all have detectable virus-neutralizing antibodies, suggesting immunity. Our results showing that not all COVID-19 patients develop detectable IgG using two validated commercial clinical methods, even over time, are vital for the interpretation of COVID-19 seroprevalence surveys.
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| 3. |
- Yilmaz, Aylin, 1974, et al.
(författare)
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Upper respiratory tract levels of SARS-CoV-2 RNA and duration of viral RNA shedding do not differ between patients with mild and severe/critical COVID-19.
- 2021
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Ingår i: The Journal of infectious diseases. - : Oxford University Press (OUP). - 1537-6613 .- 0022-1899. ; 223:1, s. 15-18
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Tidskriftsartikel (refereegranskat)abstract
- This study reports longitudinal viral RNA loads from nasopharynx/throat in patients with mild and severe/critical COVID-19. We also investigated whether the duration of symptoms correlated with the duration of viral RNA shedding. A total of 56 patients were included. The highest viral loads occurred early after onset of symptoms. Neither the viral RNA loads in the upper respiratory tract, nor the time to viral RNA clearance differed between patients with mild or severe/critical disease. There was a moderate correlation between number of days with symptoms and number of days with viral RNA shedding in patients with mild COVID-19.
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| 4. |
- Yilmaz, Aylin, et al.
(författare)
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Upper Respiratory Tract Levels of Severe Acute Respiratory Syndrome Coronavirus 2 RNA and Duration of Viral RNA Shedding Do Not Differ Between Patients With Mild and Severe/Critical Coronavirus Disease 2019
- 2021
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Ingår i: Journal of Infectious Diseases. - : Oxford University Press (OUP). - 1537-6613 .- 0022-1899. ; 223:1, s. 15-18
-
Tidskriftsartikel (refereegranskat)abstract
- This study reports longitudinal viral RNA loads from the nasopharynx/throat in patients with mild and severe/critical coronavirus disease 2019 (COVID-19). We also investigated whether the duration of symptoms correlated with the duration of viral RNA shedding. A total of 56 patients were included. The highest viral loads occurred early after onset of symptoms. Neither the viral RNA loads in the upper respiratory tract nor the time to viral RNA clearance differed between patients with mild or severe/critical disease. There was a moderate correlation between number of days with symptoms and number of days with viral RNA shedding in patients with mild COVID-19.
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| 5. |
- Lundgren, Anna, 1974, et al.
(författare)
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Plasmablasts in previously immunologically naive COVID-19 patients express markers indicating mucosal homing and secrete antibodies cross-reacting with SARS-CoV-2 variants and other beta-coronaviruses
- 2023
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Ingår i: Clinical and Experimental Immunology. - 0009-9104 .- 1365-2249. ; 213:2, s. 173-89
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Tidskriftsartikel (refereegranskat)abstract
- Antigen-specific class-switched antibodies are detected at the same time or even before IgM in serum of non-vaccinated individuals infected with SARS-CoV-2. These derive from the first wave of plasmablasts formed. Hence, the phenotype and specificity of plasmablasts can reveal information about early B-cell activation. Here we have analyzed B cells and plasmablasts circulating in blood of COVID-19 patients not previously exposed to SARS-CoV-2 during and after disease. We find that during infection with the original Wuhan strain, plasmablasts in blood produce IgA1, IgG1, and IgM, and that most express CCR10 and integrin beta 1, only some integrin beta 7, while the majority lack CCR9. Plasmablast-secreted antibodies are reactive to the spike (S) and nucleocapsid (N) proteins of the Wuhan strain as well as later variants of concern, but also bind S proteins from endemic and non-circulating betacoronaviruses. In contrast, after recovery, antibodies produced from memory B cells target variants of SARS-CoV-2 and SARS-CoV-1 but compared to previously non-infected individuals do not show increased binding to endemic coronaviruses. This suggests that the early antibody response to a large extent stems from pre-existing cross-reactive class-switched memory B cells, and that although newly formed memory cells target the novel SARS-CoV-2 virus the numbers of broadly cross-reactive memory B cells do not increase extensively. The observations give insight into the role of pre-existing memory B cells in early antibody responses to novel pathogens and may explain why class-switched antibodies are detected early in the serum of COVID-19 patients. During an infection, plasmablasts circulating in blood represent ongoing formation of antibody-producing cells from activated B cells. Here we study the early plasmablasts in previously naive COVID-19 patients arriving at hospital. We find extensive cross-reactivity to circulating and non-circulating beta-coronaviruses, that IgA1 responses dominate, and that the cells express markers suggesting mucosal homing.
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| 6. |
- Marklund, Emelie, et al.
(författare)
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Longitudinal Follow Up of Immune Responses to SARS-CoV-2 in Health Care Workers in Sweden With Several Different Commercial IgG-Assays, Measurement of Neutralizing Antibodies and CD4+ T-Cell Responses.
- 2021
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Ingår i: Frontiers in immunology. - : Frontiers Media SA. - 1664-3224. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- The risk of SARS-CoV-2 infection among health care workers (HCWs) is a concern, but studies that conclusively determine whether HCWs are over-represented remain limited. Furthermore, methods used to confirm past infection vary and the immunological response after mild COVID-19 is still not well defined.314 HCWs were recruited from a Swedish Infectious Diseases clinic caring for COVID-19 patients. IgG antibodies were measured using two commercial assays (Abbot Architect nucleocapsid (N)-assay and YHLO iFlash-1800 N and spike (S)-assays) at five time-points, from March 2020 to January 2021, covering two pandemic waves. Seroprevalence was assessed in matched blood donors at three time-points. More extensive analyses were performed in 190 HCWs in September/October 2020, including two additional IgG-assays (DiaSorin LiaisonXL S1/S2 and Abbot Architect receptor-binding domain (RBD)-assays), neutralizing antibodies (NAbs), and CD4+ T-cell reactivity using an in-house developed in vitro whole-blood assay based on flow cytometric detection of activated cells after stimulation with Spike S1-subunit or Spike, Membrane and Nucleocapsid (SMN) overlapping peptide pools.Seroprevalence was higher among HCWs compared to sex and age-matched blood donors at all time-points. Seropositivity increased from 6.4% to 16.3% among HCWs between May 2020 and January 2021, compared to 3.6% to 11.9% among blood donors. We found significant correlations and high levels of agreement between NAbs and all four commercial IgG-assays. At 200-300 days post PCR-verified infection, there was a wide variation in sensitivity between the commercial IgG-assays, ranging from <30% in the N-assay to >90% in the RBD-assay. There was only moderate agreement between NAbs and CD4+ T-cell reactivity to S1 or SMN. Pre-existing CD4+ T-cell reactivity was present in similar proportions among HCW who subsequently became infected and those that did not.HCWs in COVID-19 patient care in Sweden have been infected with SARS-CoV-2 at a higher rate compared to blood donors. We demonstrate substantial variation between different IgG-assays and propose that multiple serological targets should be used to verify past infection. Our data suggest that CD4+ T-cell reactivity is not a suitable measure of past infection and does not reliably indicate protection from infection in naive individuals.
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| 7. |
- Scharf, Lydia, et al.
(författare)
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Longitudinal single-cell analysis of SARS-CoV-2-reactive B cells uncovers persistence of early-formed, antigen specific clones.
- 2023
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Ingår i: JCI insight. - : American Society for Clinical Investigation. - 2379-3708. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Understanding persistence and evolution of B cell clones after COVID-19 infection and vaccination is crucial for predicting responses against emerging viral variants and optimizing vaccines. Here, we collected longitudinal samples from severe COVID-19 patients every third to seventh day during hospitalization and every third month after recovery. We profiled the antigen-specific immune cell dynamics by combining single cell RNA-Seq, Cellular Indexing of Transcriptomes and Epitopes by Sequencing (CITE)-Seq, B cell receptor (BCR)-Seq with oligo-tagged antigen baits. While the proportion of Spike Receptor Binding Domain-specific memory B cells (MBC) increased from 3 months after infection, the other Spike- and Nucleocapsid-specific B cells remained constant. All patients showed ongoing class switching and sustained affinity maturation of antigen specific cells, which was not significantly increased early after vaccine. B cell analysis revealed a polyclonal response with limited clonal expansion; nevertheless, some clones detected during hospitalization, as plasmablasts, persisted for up to one year, as MBC. Monoclonal antibodies derived from persistent B cell families increased their binding and neutralization breadth and started recognizing viral variants by 3 months after infection. Overall, our findings provide important insights into the clonal evolution and dynamics of antigen specific B cell responses in longitudinally sampled COVID-19 infected patients.
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| 8. |
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| 9. |
- Andersson, Jim, et al.
(författare)
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Methanol production via pressurized entrained flow biomass gasification : Techno-economic comparison of integrated vs. stand-alone production
- 2014
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Ingår i: Biomass and Bioenergy. - : Elsevier BV. - 0961-9534 .- 1873-2909. ; 64, s. 256-268
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Tidskriftsartikel (refereegranskat)abstract
- The main objective with this work was to investigate techno-economically the opportunity for integrated gasification-based biomass-to-methanol production in an existing chemical pulp and paper mill. Three different system configurations using the pressurized entrained flow biomass gasification (PEBG) technology were studied, one stand-alone plant, one where the bark boiler in the mill was replaced by a PEBG unit and one with a co-integration of a black liquor gasifier operated in parallel with a PEBG unit. The cases were analysed in terms of overall energy efficiency (calculated as electricity-equivalents) and process economics. The economics was assessed under the current as well as possible future energy market conditions. An economic policy support was found to be necessary to make the methanol production competitive under all market scenarios. In a future energy market, integrating a PEBG unit to replace the bark boiler was the most beneficial case from an economic point of view. In this case the methanol production cost was reduced in the range of 11-18 Euro per MWh compared to the stand-alone case. The overall plant efficiency increased approximately 7%-units compared to the original operation of the mill and the non-integrated stand-alone case. In the case with co-integration of the two parallel gasifiers, an equal increase of the system efficiency was achieved, but the economic benefit was not as apparent. Under similar conditions as the current market and when methanol was sold to replace fossil gasoline, co-integration of the two parallel gasifiers was the best alternative based on received IRR.
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| 10. |
- Aronsson, Gunnar, et al.
(författare)
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The changing nature of work - Job strain, job support and sickness absence among care workers and in other occupations in Sweden 1991-2013
- 2021
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Ingår i: SSM - Population Health. - : Elsevier BV. - 2352-8273. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- This study examined exposure changes in three psychosocial dimensions - job demands, job control, and social support - and the associations between these dimensions and sickness absence throughout the period 1991-2013. The analyses covered periods of economic ups and downs in Sweden and periods involving major fluctuations in sickness absence. Data on care workers (n = 16,179) and a comparison group of employees in other occupations (n = 82,070) were derived from the biennial Swedish Work Environment Survey and linked to register data on sickness absence. Eight exposure profiles, based on combinations of demands, control, and support, were formed. The proportion of individuals with work profiles involving high demands doubled among care workers (14%-29%) while increasing modestly in the comparison group (17%-21%) 1991-2013. The work profile that isolated high-strain (iso-strain), i.e., high demands, low control, and low social support, was more prevalent among care workers, from 4% in 1991 to 11% in 2013. Individuals with work profiles involving highdemand jobs had the highest number of days on sickness absence during the study period and those with the isostrain work profile had the highest increase in sickness absence, from 15 days per year during 1993-1994, to 42 days during 2000-2002. Employees with a passive work profile (low job demands and low job control) had the lowest rate and the lowest increase in sickness absence. Individuals with active work profiles, where high demands are supposed to be balanced by high job control, had a rather high increase in sickness days around 2000. A conclusion is that there is a long-term trend towards jobs with high demands. This trend is stronger among care workers than among other occupations. These levels of job demands seem to be at such a level that it is difficult to compensate for with higher job control and social support.
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| 11. |
- Barnes, Brian R, et al.
(författare)
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The 5'-AMP-activated protein kinase gamma3 isoform has a key role in carbohydrate and lipid metabolism in glycolytic skeletal muscle
- 2004
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 279:37, s. 38441-38447
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Tidskriftsartikel (refereegranskat)abstract
- 5'-AMP-activated protein kinase (AMPK) is a metabolic stress sensor present in all eukaryotes. A dominant missense mutation (R225Q) in pig PRKAG3, encoding the muscle-specific gamma3 isoform, causes a marked increase in glycogen content. To determine the functional role of the AMPK gamma3 isoform, we generated transgenic mice with skeletal muscle-specific expression of wild type or mutant (225Q) mouse gamma3 as well as Prkag3 knockout mice. Glycogen resynthesis after exercise was impaired in AMPK gamma3 knock-out mice and markedly enhanced in transgenic mutant mice. An AMPK activator failed to increase skeletal muscle glucose uptake in AMPK gamma3 knock-out mice, whereas contraction effects were preserved. When placed on a high fat diet, transgenic mutant mice but not knock-out mice were protected against excessive triglyceride accumulation and insulin resistance in skeletal muscle. Transfection experiments reveal the R225Q mutation is associated with higher basal AMPK activity and diminished AMP dependence. Our results validate the muscle-specific AMPK gamma3 isoform as a therapeutic target for prevention and treatment of insulin resistance.
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| 12. |
- Bartley, Andreas, et al.
(författare)
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Effect of Irrigation Fluid Temperature on Recurrence in the Evacuation of Chronic Subdural Hematoma A Randomized Clinical Trial
- 2023
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Ingår i: Jama Neurology. - : American Medical Association (AMA). - 2168-6149 .- 2168-6157.
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Tidskriftsartikel (refereegranskat)abstract
- ImportanceThe effect of a physical property of irrigation fluid (at body vs room temperature) on recurrence rate in the evacuation of chronic subdural hematoma (cSDH) needs further study.ObjectiveTo explore whether irrigation fluid temperature has an influence on cSDH recurrence.Design, Setting, and ParticipantsThis was a multicenter randomized clinical trial performed between March 16, 2016, and May 30, 2020. The follow-up period was 6 months. The study was conducted at 3 neurosurgical departments in Sweden. All patients older than 18 years undergoing cSDH evacuation during the study period were screened for eligibility in the study.InterventionsThe study participants were randomly assigned by 1:1 block randomization to the cSDH evacuation procedure with irrigation fluid at room temperature (RT group) or at body temperature (BT group).Main Outcomes and MeasuresThe primary end point was recurrence requiring reoperation within 6 months. Secondary end points were mortality, health-related quality of life, and complication frequency.ResultsAt 6 months after surgery, 541 patients (mean [SD] age, 75.8 [9.8] years; 395 men [73%]) had a complete follow-up according to protocol. There were 39 of 277 recurrences (14%) requiring reoperation in the RT group, compared with 16 of 264 recurrences (6%) in the BT group (odds ratio, 2.56; 95% CI, 1.38-4.66; P < .001). There were no significant differences in mortality, health-related quality of life, or complication frequency.Conclusions and RelevanceIn this study, irrigation at body temperature was superior to irrigation at room temperature in terms of fewer recurrences. This is a simple, safe, and readily available technique to optimize outcome in patients with cSDH. When irrigation is used in cSDH surgery, irrigation fluid at body temperature should be considered standard of care.
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| 13. |
- Bartley, Andreas, et al.
(författare)
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The Swedish study of Irrigation-fluid temperature in the evacuation of Chronic subdural hematoma (SIC!) : study protocol for a multicenter randomized controlled trial
- 2017
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Ingår i: Trials. - : BIOMED CENTRAL LTD. - 1745-6215. ; 18
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Tidskriftsartikel (refereegranskat)abstract
- Background: Chronic subdural hematoma (cSDH) is one of the most common conditions encountered in neurosurgical practice. Recurrence, observed in 5-30% of patients, is a major clinical problem. The temperature of the irrigation fluid used during evacuation of the hematoma might theoretically influence recurrence rates since irrigation fluid at body temperature (37 degrees C) may beneficially influence coagulation and cSDH solubility when compared to irrigation fluid at room temperature. Should no difference in recurrence rates be observed when comparing irrigation-fluid temperatures, there is no need for warmed fluids during surgery. Our main aim is to investigate the effect of irrigation-fluid temperature on recurrence rates and clinical outcomes after cSDH evacuation using a multicenter randomized controlled trial design.Methods: The study will be conducted in three neurosurgical departments with population-based catchment areas using a similar surgical strategy. In total, 600 patients fulfilling the inclusion criteria will randomly be assigned to either intraoperative irrigation with fluid at body temperature or room temperature. The power calculation is based on a retrospective study performed at our department showing a recurrence rate of 5% versus 12% when comparing irrigation fluid at body temperature versus fluid at room temperature (unpublished data). The primary endpoint is recurrence rate of cSDH analyzed at 6 months post treatment. Secondary endpoints are mortality rate, complications and health-related quality of life.Discussion: Irrigation-fluid temperature might influence recurrence rates in the evacuation of chronic subdural hematomas. We present a study protocol for a multicenter randomized controlled trial investigating our hypothesis that irrigation fluid at body temperature is superior to room temperature in reducing recurrence rates following evacuation of cSDH.
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| 14. |
- Bergman Ärlebäck, Jonas, 1972-
(författare)
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Conformal Einstein spaces and Bach tensor generalization in n dimensions
- 2004
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis we investigate necessary and su±cient conditions for an n-dimensional space, n ≥ 4, to be locally conformal to an Einstein space. After reviewing the classical results derived in tensors we consider the four-dimensional spinor result of Kozameh, Newman and Tod. The involvement of the four-dimensional Bach tensor (which is divergence-free and conformally well-behaved) in their result motivates a search for an n-dimensional generalization of the Bach tensor Bab with the same properties. We strengthen a theorem due to Belfagón and Jaén and give a basis (Uab, V ab and Wab) for all n-dimensional symmetric, divergence-free 2-index tensors quadratic in the Riemann curvature tensor. We discover the simple relationship Bab = 1/2Uab + 1/6V ab and show that the Bach tensor is the unique tensor with these properties in four dimensions. Unfortunately we have to conclude, in general that there is no direct analogue in higher dimension with all these properties.Nevertheless, we are able to generalize the our-dimensional results due to Kozameh, Newman and Tod to n dimensions. We show that a generic space is conformal to an Einstein space if and only if there exists a vector field satisfying two conditions. The explicit use of dimensionally dependent identities (some of which are newly derived in this thesis) is also exploited in order to make the two conditions as simple as possible; explicit examples are given in five and six dimensions using these tensor identities. For n dimensions, we define the tensors babc and Bab, and we show that their vanishing is a conformal invariant property which guarantees that the space with non-degenerate Weyl tensor is a conformal Einstein space.
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| 15. |
- Berntson, Erik, 1975-
(författare)
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Employability perceptions : Nature, determinants, and implications for health and well-being
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The general aim of the present thesis is to increase our understanding of perceived employability. Employability perceptions refer to individuals’ beliefs about their possibilities of finding new, equal, or better employment. How people perceive their possibilities of getting employment is important in a labour market characterised by flexibility and uncertainty, and the present thesis sets out to investigate the nature, determinants, and implications of employability perceptions, using two population-based samples. In Study I, the aim was to study if employability and self-efficacy are two distinct but related constructs and, along with this, to investigate the nature of their association. The results from this study indicated that employability was distinct from self-efficacy and, furthermore, that employability predicted subsequent self-efficacy. In Study II, the aim was to identify predictors of perceived employability. The combination of situational and individual factors was identified as important for employability perceptions. National economic prosperity, living/working in metropolitan areas, poor physical and good psychological work environments, formal education, and competency development were found to be positively associated with perceived employability. The aim of Study III was to investigate if employability could predict subsequent health and well-being. The results from this study implied that individuals who reported higher levels of employability also reported better global health and mental well-being, but not physical complaints, one year later, after controlling for work environment variables and previous health status. In conclusion, the present thesis has implications for theory as well as practice when it concludes that employability is not primarily a self-evaluation, that it is dependent on individual as well as situational factors, and that it has implications for health and well-being.
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| 16. |
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| 17. |
- Berntson, Erik, et al.
(författare)
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Predicting perceived employability: Human capital or labour market opportunities?
- 2006
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Ingår i: Economic and Industrial Democracy. - 0143-831X. ; 27:2, s. 223-244
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Tidskriftsartikel (refereegranskat)abstract
- Employability is believed to be a crucial concept concerning employees’ job security. This study investigates whether factors associated with human capital and the dual labour market predict perceived employability. Two national representative Swedish samples are used, representing economic recession (1993, N 1³4 4952) and prosperity (1999, N 1³4 6696). Employability was perceived as higher during prosperity, but human capital factors as well as dual labour market factors predicted perceived employability, irrespective of the time period. These findings indicate that the understanding of employability is enhanced by considering both structural and individual dimensions.
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| 18. |
- Bobinski, Lukas, 1977-
(författare)
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On evolution of intracranial changes after severe traumatic brain injury and its impact on clinical outcome
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Severe traumatic brain injury (sTBI) is a cause of death and disability worldwide and requires treatment at specialized neuro-intensive care units (NICU) with a multimodal monitoring approach. The CT scan imaging supports the monitoring and diagnostics. The level of S100B and neuron specific enolase (NSE) reflects the severity of the injury. The therapy resistant intracranial hypertension requires decompressive craniectomy (DC). After DC, the cranium must be reconstructed to recreate the normal intracranial physiology as well as to address cosmetic issues. The evolution of the pathological intracranial changes was analyzed in accordance with the three CT classifications: Marshall, Rotterdam and Morris-Marshall. The Rotterdam scale was best in describing the dynamics of the pathological evolution. Both the Rotterdam score and Morris- Marshall classification showed strong correlation with the clinical outcome, a finding that suggests that they could be used for prognostication. We demonstrated a clear correlation between the CT classifications and concentrations of S100B and NSE. The results revealed a concomitant correlation between NSE and S100B and clinical outcome. We found that the interaction between the ICP, Rotterdam CT classification, and concentrations of biochemical biomarkers are all associated with DC. We found a high percentage of complications following cranioplasty. Our results call into question whether custom-made allograft should be considered the best material for cranioplasty. It is concluded that both the Rotterdam and Morris-Marshall classification contribute to clinical evaluation of intracranial dynamics after sTBI, and might be used in combination with biochemical biomarkers for better assessment. The decision to perform DC should include a re-assesment of ICP evolution, CT scan images and concentration of the biochemical biomarkers. Furthermore, when determining whether DC treatment should be used, surgeon should also consider the risks of the following cranioplasty.
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| 19. |
- Brännlund, Runar, 1957-, et al.
(författare)
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Evaluating market efficiency without price data : The Swedish market for wood fuel
- 2004
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Ingår i: Applied Economics. - : Routledge Taylor Francis Group. - 0003-6846 .- 1466-4283. ; 36:1, s. 31-39
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Tidskriftsartikel (refereegranskat)abstract
- The overall objective of this paper is to analyse the price development and price formation for wood fuel used by the Swedish district heating sector. According to Lnner et al., there is a significant potential for increasing the use of wood fuel in Sweden, at a fairly moderate cost. The basic question raised in this paper is then why this potential is not realized. Specifically, a methodology is proposed for testing whether the reason is that market imperfections are present. As a first step the shape of the technology in the Swedish district heating sector is estimated for the period 1989 to 1996. In the second step the estimated technology and the assumption of cost-minimizing firms are combined to calculate shadow prices, i.e. marginal valuation of wood fuel in this sector. If the average shadow price significantly deviates from the average observed price one may conclude that this market is functioning inefficiently due to imperfections. According to constructed bootstrap confidence intervals this difference is significant only for three out of eight years, implying that the quantities of wood fuel traded are too small. For the other years the difference is not significant, implying that one cannot, on statistical grounds, reject the efficient market hypothesis for all years.
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| 20. |
- Bäckström, Magnus, et al.
(författare)
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Luftspolning av tryckavloppsledningar för bekämpning av svavelväte
- 2010
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Luftspolning av tryckavloppsledningar har utprovats som ett alternativ för att förhindra svavelvätebildning i avloppsnätet. Syftet med luftspolningen är att tömma tryckledningen på spillvatten och på detta sätt förkorta uppehållstiden samtidigt som de sulfidbildande mikroorganismerna i ledningen får ett betydligt tuffare liv. Fullskaleförsök visar att luftspolning är ett realistiskt och fungerande alternativ för bekämpning av svavelväte i avloppsnät. Luftspolningstekniken har dock sina begränsningar, som då tryckavloppsledningen har tydliga höjdpunkter och svackor.
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| 21. |
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| 22. |
- Carlsson, Per, et al.
(författare)
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Comparison and validation of gas phase reaction schemes for black liquor gasification modeling
- 2008
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Ingår i: Conference Proceedings 2008 AiChE annual meeting.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Pressurized Entrained-flow High Temperature Black Liquor Gasification (PEHT-BLG) is a potential substitute or complement to the recovery boiler traditionally used for the recovery of chemicals and energy in black liquor in the Kraft pulping process. Black liquor consists of roughly 30 % moisture, 35 % inorganic pulping chemicals and 35 % combustible material (i.e. lignin). The PEHT-BLG technology can give an increase in total energy efficiency of the mill and provide new products with high added value, such as green motor fuels. The main parts of the recovery unit in the process are; a slagging refractory lined entrained-flow gasification reactor, with a gas assisted burner nozzle producing small black liquor droplets, used for direct gasification of the black liquor at about 1000 °C to produce a ‘raw' syngas and a liquid smelt containing mainly Na2CO3 and Na2S; a quench cooler beneath the reactor where the product gas and smelt are separated and the smelt is dissolved in water forming green liquor; a counter current condenser (CCC) that cools the syngas and condenses water vapor and any volatile and tar species that may be present. The heat recovered from the gas condensation is used to generate low/medium pressure steam that can be used in the pulp and paper process. Furthermore, the chemicals in the green liquor are recovered as cooking chemicals in the downstream processing. Due to lack of demonstration of long term operation of the technology, a development (pilot) plant for PEHT-BLG (named DP-1) with a capacity of 20 tones dry solids/24h is in operation by the technology vendor Chemrec AB at the Energy Technology Centre in Piteå, Sweden. An important tool for reduction of the technical risk associated with scale up of new technology is a comprehensive CFD model for the PEHT-BLG reactor. The current model includes drying, pyrolysis, char gasification and smelt formation of black liquor droplets as well as a simplified gas phase reaction mechanism. The current model has been validated against the outlet gas composition after the Counter Current Condenser (CCC). The model predicted a CO / CO2 ratio that was approximately 50% higher compared to the measurements. However, it is possible that the well known water-gas shift reaction is active in the quench and this could explain that the experimentally determined gas composition after the CCC differs from the computational results at the outlet from the hot zone. Recently, in-situ measurements have been performed in the DP-1 reactor and a further validation of the model has been made possible. The measurements have been performed by sampling gas with a water-cooled suction probe from the lower part of the hot zone, followed by offline gas analyses. The present paper investigates the difference between the current CFD-model and a modified version with an additional CO + O2 reaction added to the simplified gas phase reaction scheme. The simulation results are compared against measurements obtained by the gas sampling probe in the DP-1 reactor. The results suggest that by implementing the additional CO + O2 reaction local flame temperature was increased significantly. However, the effect on volume average and outlet gas temperature was minimal.The results also showed that the CO + O2 reaction had very little effect on outlet gas composition when the reaction was implemented in the PEHT-BLG-CFD model
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| 23. |
- Carlsson, Per, et al.
(författare)
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Experimental investigation of an industrial scale black liquor gasifier : 1. Influence of reactor operation parameters on product gas composition
- 2010
-
Ingår i: Fuel. - : Elsevier BV. - 0016-2361 .- 1873-7153. ; 89:12, s. 4025-4034
-
Tidskriftsartikel (refereegranskat)abstract
- A novel technology to mitigate the climate changes and improve energy security is Pressurized Entrained flow High Temperature Black Liquor Gasification (PEHT-BLG) in combination with an efficient fuel synthesis using the resulting syngas. In order to optimise the technology for use in a pulp and paper mill based biorefinery, it is of great importance to understand how the operational parameters of the gasifier affect the product gas composition. The present paper is based on experiments where gas samples were withdrawn from the hot part of a 3 MW entrained flow pressurized black liquor gasifier of semi industrial scale using a high temperature gas sampling system. Specifically, the influence of process conditions on product gas composition (CO2, CO, H2, CH4, H2S, and COS) were examined by systematically varying the operational parameters: system pressure, oxygen to black liquor equivalence ratio, black liquor flow rate to pressure ratio and black liquor pre-heat temperature. Due to the harsh environment inside the gasification reactor, gas sampling is a challenging task. However, for the purpose of the current study, a specially designed high temperature gas sampling system was successfully developed and used. The results, obtained from two separate experimental campaigns, show that all of the investigated operational parameters have a significant influence on the product gas composition and present valuable information about to the process characteristics.
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| 24. |
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| 25. |
- Carlsson, Per, et al.
(författare)
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Experiments and mathematical models of black liquor gasification – influence of minor gas components on temperature, gas composition, and fixed carbon conversion
- 2010
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Ingår i: TAPPI Journal. - 0734-1415. ; 9:9, s. 15-24
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Forskningsöversikt (refereegranskat)abstract
- In this work, predictions from a reacting Computational Fluid Dynamics (CFD) model of a gasification reactor are compared to experimentally obtained data from an industrial pressurized black liquor gasification plant. The data consists of gas samples taken from the hot part of the gasification reactor using a water cooled sampling probe. During the considered experimental campaign, the oxygen-to-black liquor equivalence ratio (λ) was varied in three increments, which resulted in a change in reactor temperature and gas composition. The presented numerical study consists of CFD and thermodynamic equilibrium calculations in the considered λ-range using boundary conditions obtained from the experimental campaign. Specifically, the influence of methane concentration on the gas composition is evaluated using both CFD and thermodynamic equilibrium. The results show that the main gas components (H2, CO, CO2) can be predicted within a relative error of 5% using CFD if the modeled release of H2S and CH4 are specified a priori. In addition, the calculations also show that the methane concentration has large influence on the reactor outlet temperature and final carbon conversion.
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| 26. |
- Carlsson, Per, et al.
(författare)
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Spatially resolved measurements of gas composition in a pressurised black liquor gasifier
- 2009
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Ingår i: Environmental Progress & Sustainable Energy. - : Wiley. - 1944-7442 .- 1944-7450. ; 28:3, s. 316-323
-
Tidskriftsartikel (refereegranskat)abstract
- Black liquor gasification is a new process for recovery of energy and chemicals in black liquor from the Kraft pulping process. The process can be combined with catalytic conversion of syngas into motor fuels. The potential for motor fuel production from black liquor in Sweden is to replace about 25% of the current consumption ofgasoline and diesel. For Finland the figure is even higher while for Canada it is about 14% and for the USA about 2%. © 2009 American Institute of Chemical Engineers Environ Prog, 28: 316-323, 2009.
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| 27. |
- Elliott, Douglas C., et al.
(författare)
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Results of the International Energy Agency Round Robin on Fast Pyrolysis Bio-oil Production
- 2017
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Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 31:5, s. 5111-5119
-
Tidskriftsartikel (refereegranskat)abstract
- An international round robin study of the production of fast pyrolysis bio-oil was undertaken. A total of 15 institutions in six countries contributed. Three biomass samples were distributed to the laboratories for processing in fast pyrolysis reactors. Samples of the bio-oil produced were transported to a central analytical laboratory for analysis. The round robin was focused on validating the pyrolysis community understanding of production of fast pyrolysis bio-oil by providing a common feedstock for bio-oil preparation. The round robin included: distribution of three feedstock samples, hybrid poplar, wheat straw, and a blend of lignocellulosic biomasses, from a common source to each participating laboratory, preparation of fast pyrolysis bio-oil in each laboratory with the three feedstocks provided, and return of the three bio-oil products (minimum of 500 mL) with operational description to a central analytical laboratory for bio-oil property determination. The analyses of interest were CHN, S, trace element analysis, water, ash, solids, pyrolytic lignin, density, viscosity, carboxylic acid number, and accelerated aging of bio-oil. In addition, an effort was made to compare the bio-oil components to the products of analytical pyrolysis through gas chromatography/mass spectrometry (GC/MS) analysis. The results showed that clear differences can occur in fast pyrolysis bio-oil properties by applying different process configurations and reactor designs in small scale. The comparison to the analytical pyrolysis method suggested that pyrolysis (Py)-GC/MS could serve as a rapid qualitative screening method for bio-oil composition when produced in small-scale fluid-bed reactors. Gel permeation chromatography was also applied to determine molecular weight information. Furthermore, hot vapor filtration generally resulted in the most favorable bio-oil product, with respect to water, solids, viscosity, and carboxylic acid number. These results can be helpful in understanding the variation in bio-oil production methods and their effects on bio-oil product composition.
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| 28. |
- Forsberg, Karin, et al.
(författare)
-
Novel antibodies reveal inclusions containing non-native SOD1 in sporadic ALS patients
- 2010
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Ingår i: PLOS ONE. - : Public library of science. - 1932-6203. ; 5:7, s. e11552-
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Tidskriftsartikel (refereegranskat)abstract
- Mutations in CuZn-superoxide dismutase (SOD1) cause amyotrophic lateral sclerosis (ALS) and are found in 6% of ALS patients. Non-native and aggregation-prone forms of mutant SOD1s are thought to trigger the disease. Two sets of novel antibodies, raised in rabbits and chicken, against peptides spaced along the human SOD1 sequence, were by enzyme-linked immunosorbent assay and an immunocapture method shown to be specific for denatured SOD1. These were used to examine SOD1 in spinal cords of ALS patients lacking mutations in the enzyme. Small granular SOD1-immunoreactive inclusions were found in spinal motoneurons of all 37 sporadic and familial ALS patients studied, but only sparsely in 3 of 28 neurodegenerative and 2 of 19 non-neurological control patients. The granular inclusions were by confocal microscopy found to partly colocalize with markers for lysosomes but not with inclusions containing TAR DNA binding protein-43, ubiquitin or markers for endoplasmic reticulum, autophagosomes or mitochondria. Granular inclusions were also found in carriers of SOD1 mutations and in spinobulbar muscular atrophy (SBMA) patients and they were the major type of inclusion detected in ALS patients homozygous for the wild type-like D90A mutation. The findings suggest that SOD1 may be involved in ALS pathogenesis in patients lacking mutations in the enzyme.
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| 29. |
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| 30. |
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| 31. |
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| 32. |
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| 33. |
- Gullberg, Marcus, et al.
(författare)
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Spray characterization of twin fluid externalmix atomization of pyrolysis oil
- 2012
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Ingår i: Atomization and sprays. - 1044-5110 .- 1936-2684. ; 22:11, s. 897-919
-
Tidskriftsartikel (refereegranskat)abstract
- The development of biomass-based energy conversion technologies has gradually been intensified throughout the last decade. The route based on pressurized entrained flow biomass gasification has an important role in this development. However, the issues of logistics and handling of the biomass requires thorough and detailed process integration studies in order to find optimal ways of imple- mentation of this technology. An interesting approach is to liquefy the biomass via fast pyrolysis to produce a bio-oil, which then could be disintegrated into the gasifier. In order to better understand how a generic type of externally gas-assisted atomizer performs for pyrolysis oil, spray characteriza- tion based on high-speed photography and case-independent image analysis were performed. Three different parameters were varied in order to study the atomization performance for the considered nozzle: The ambient pressure, the pyrolysis oil temperature, and the length of external extension of the prefilming center bluff body in the nozzle. It was found that an increase in ambient pressure and corresponding load as well as an extension of the center bluff body of the nozzle led to degradation in atomization performance. On the other hand, a moderate temperature increase that affects the fluid properties in a favorable way improved the atomization performance. In all considered cases for the tested nozzle, a notable fraction of the droplets in the spray were found in the large-size tail of the size distributions and it is uncertain whether this may have an effect on the fuel conversion in the gasification process.
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| 34. |
- Gustafsson, Klas, et al.
(författare)
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Presenteeism, Psychosocial Working Conditions and Work Ability among Care Workers : A Cross-Sectional Swedish Population-Based Study
- 2020
-
Ingår i: International Journal of Environmental Research and Public Health. - : MDPI AG. - 1661-7827 .- 1660-4601. ; 17:7
-
Tidskriftsartikel (refereegranskat)abstract
- Presenteeism, attending work while ill, has been examined in different contexts in the last few decades. The aim was to examine whether poor psychosocial working conditions and perceived work ability are associated with increased odds ratios for presenteeism, focusing on nursing professionals and care assistants. A cross-sectional population-based study was conducted. The selected individuals were extracted from representative samples of employees, aged 16-64, who participated in the Swedish Work Environment Surveys between 2001 and 2013 (n = 45,098). Three dimensions of psychosocial working conditions were measured: job demands, job control, and job support. Presenteeism and perceived work ability was measured. Using multiple logistic regression analyses, odds ratios for presenteeism with 95% confidence intervals (CI) were estimated. While nurses (n = 1716) showed the same presenteeism level as all the other occupation groups (n = 37,125), it was more common among care assistants (n = 6257). The odds ratio for presenteeism among those with high job demands (OR = 2.37, 95% CI 2.21-2.53), were higher among women than among men. For nursing professionals and care assistants, the odds ratios for presenteeism were highest among those with the lowest work ability level. The problems of presenteeism and low work ability among many health and care workers may be lessened by a reduction in psychosocial demands.
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| 35. |
- Gärdlund, Linda, et al.
(författare)
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The use of polyelectrolyte complexes (PEC) as strength additives for different pulps used for production of fine paper
- 2007
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Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 22:2, s. 210-216
-
Tidskriftsartikel (refereegranskat)abstract
- In this work the application of polyelectrolyte complexes (PEC) to different pulps, to improve the strength of papers produced from them, is compared with conventional pulp beating. The pulps chosen for the investigation were a fully bleached chemical hardwood pulp (HBK), a fully bleached chemical softwood pulp (SBK), and a peroxide-bleached chemithermomechanical pulp (BCTMP). The polyelectrolytes used were a polyamideamine epichlorohydrine condensate (PAE), traditionally used as a wet-strength additive, and carboxymethylcellulose. Since the prepared complexes had an anionic charge, they could only be used after fibre pre-treatment with the cationic PAE. Results indicate that the addition of 2% PAE and 2% PEC can improve all the measured tensile strength properties of the sheets as much as is commonly achieved by mechanically beating the pulps. In fact, for the chemical pulps, PEC addition at the chosen level produced better results than did traditional beating, since the improved tensile index and tensile energy absorption could be achieved without any significant deterioration in the light scattering coefficient of the papers produced. However, with the BCTMP a significant decrease in light scattering could be detected, especially following the addition of PEC. Adding the chemicals (especially the PEC) increased the sheet density and this together with the increase in the tensile stiffness, following chemical addition, resulted in a constant bending stiffness of the sheets. However, based on the results it can be suggested that a combination of unbeaten HBK and BCTMP treated with PAE and PEC can be used to produce a strong paper with a high bending stiffness.
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| 36. |
- Helgesson, Magnus, et al.
(författare)
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Favorable Working Conditions Related to Health Behavior Among Nurses and Care Assistants in Sweden-A Population-Based Cohort Study
- 2021
-
Ingår i: Frontiers In Public Health. - : Frontiers Media SA. - 2296-2565. ; 9
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: To analyze the associations between favorable physical and psychosocial work factors and health behavior among healthcare employees (nurses and care assistants) with health complaints.Methods: The study was based on seven iterations (2001-2013) of a biennial Swedish work environment survey linked with data from public registers. In all, 7,180 healthcare employees, aged 16-64 years, who had reported health complaints, were included. Health behavior was operationalized through four combinations of sickness absence (SA) and sickness presence (SP): 'good health behavior' (Low SP/Low SA), 'recovery behavior' (Low SP/High SA), 'risk behavior' (High SP/Low SA), and 'poor health behavior' (High SP/High SA). Odds ratios (OR) were calculated by multinomial logistic regression with 95% confidence intervals (CI).Results: After adjusting for socio-demographic factors, those who rarely worked in strenuous postures had an increased probability of having 'good health behavior' (OR range: nurses 1.72-2.02; care assistants 1.46-1.75). Those who rarely experienced high job demands had increased odds for having 'good health behavior' (OR: nurses 1.81; OR range: care assistants 1.67-2.13), while having good job control was found to be related to 'good health behavior' only among care assistants (OR range 1.30-1.68). In the full model, after also considering differences in health, none of the work environment indicators affected 'good health behavior' among nursing professionals. Among care assistants, rarely having heavy physical work and having low psychosocial demands remained significantly associated with 'good health behavior' (OR range: 1.24-1.58) and 'recovery behavior' (OR range: 1.33-1.70). No associations were found between favorable work environment factors and 'risk behavior' among the two groups of employees. However, positive assessments of the work situation were associated with 'good health behavior,' even after controlling for all confounders for both groups (OR range: 1.43-2.69).Conclusions: 'Good health behavior' and 'recovery behavior' among care assistants were associated with favorable physical and psychosocial working conditions even when health was considered. This implies that reduced sickness presence and sickness absence among care assistants can be achieved through improved physical and psychosocial working conditions.
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| 37. |
- Helgesson, Magnus, et al.
(författare)
-
Interaction Effects of Physical and Psychosocial Working Conditions on Risk for Sickness Absence : A Prospective Study of Nurses and Care Assistants in Sweden
- 2020
-
Ingår i: International Journal of Environmental Research and Public Health. - : MDPI AG. - 1661-7827 .- 1660-4601. ; 17:20
-
Tidskriftsartikel (refereegranskat)abstract
- Employees in health and social care are often simultaneously exposed to both physical and psychosocial challenges that may increase their risk for sickness absence. The study examines interaction effects of physical and psychosocial work conditions on the future risk for sickness absence among nurses and care assistants in Sweden. The study was based on 14,372 participants in any of the Swedish Work Environment Surveys conducted during the years 1993-2013 with linked register information on background factors and compensated sickness absence. Adjusted hazard ratio (HR), stratified by occupation, and measures of additive interaction effects were estimated. The combinations of high psychosocial job demands and heavy physical work and strenuous postures, respectively, significantly increased the risks for sickness absence among nurses (HR 1.43; CI 1.09-1.88 and HR 1.42; CI 1.16-1.74, respectively), as well as among care assistants (HR 1.51; CI 1.36-1.67 and HR 1.49; CI 1.36-1.63, respectively). The combinations of low job control and both heavy physical work (HR 1.44; CI 1.30-1.60) and strenuous postures (HR 1.42; CI 1.30-1.56) were also associated with excess risk for sickness absence among care assistants. We also found interaction effects among care assistants but not among nurses. The results indicate that the high sickness absence rate among care workers in Sweden can be reduced if the simultaneous exposures of high psychosocial and high physical challenges are avoided. Management policies for reduced time pressure, improved lifting aids, and measures to avoid awkward work postures are recommended. For care assistants, increased influence over work arrangements is likely to lower their sickness absence risk.
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| 38. |
- Helgesson, Magnus, et al.
(författare)
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Sickness Absence and Sickness Presence Among Health and Care Employees in Sweden-Health Complaints, Health Behavior, and Future Long-Term Sickness Absence
- 2021
-
Ingår i: Journal of Occupational and Environmental Medicine. - 1076-2752 .- 1536-5948. ; 63:6, s. 514-520
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: To describe if health complaints relate to health behavior in terms of sickness absence (SA) and sickness presence (SP) and to examine how complaints and health behavior predicts the risk for future long-term sickness absence (LTSA).Methods: Data originates from work environment surveys 2001 to 2013 and SA registers 2002 to 2016 of 1838 nurses, 7430 care assistants, and 40,515 individuals in all other occupations. Descriptive and regression analyses were conducted.Results: Physical complaints and high SA in combination with high SP increased the risk of LTSA among nurses and care assistants. Nurses' high SP and care assistants' high SA elevated the LTSA risk.Conclusions: Strategies to reduce the reasons behind physical health complaints among health care workers are warranted. SP among nurses and SA among care assistants should be considered in the organization of their job demands.
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| 39. |
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| 40. |
- Jannasch, Anna-Karin, et al.
(författare)
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ANALYSIS OF P2G/P2L SYSTEMS IN PITEÅ/NORRBOTTEN FOR COMBINED PRODUCTION OF LIQUID AND GASEOUS BIOFUELS : Report from an f3 project
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report is the result of a collaborative project within the Swedish Knowledge Centre for Renewable Transportation Fuels (f3). f3 is a networking organization, which focuses on development of environmentally, economically and socially sustainable renewable fuels, and Provides a broad, scientifically based and trustworthy source of knowledge for industry, governments and public authorities, Carries through system oriented research related to the entire renewable fuels value chain, Acts as national platform stimulating interaction nationally and internationally.f3 partners include Sweden’s most active universities and research institutes within the field, as well as a broad range of industry companies with high relevance. f3 has no political agenda and does not conduct lobbying activities for specific fuels or systems, nor for the f3 partners’ respective areas of interest.The f3 centre is financed jointly by the centre partners, the Swedish Energy Agency and the region of Västra Götaland. f3 also receives funding from Vinnova (Sweden’s innovation agency) as a Swedish advocacy platform towards Horizon 2020. Chalmers Industriteknik (CIT) functions as the host of the f3 organization (see www.f3centre.se).
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| 41. |
- Johannisson, Pontus, et al.
(författare)
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Suppression of nonlinear effects by phase alternation in strongly dispersion-managed optical transmission
- 2002
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Ingår i: Optics Letters. - 0146-9592 .- 1539-4794. ; 27:12
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Tidskriftsartikel (refereegranskat)abstract
- The nonlinear effects of amplitude jitter and ghost pulse generation, which are present in strongly dispersion-managed optical communication systems can be suppressed by alternation of the phase of the bits. A physical explanation for this effect is given that shows that with suitably chosen phase modulations the processes that give rise to the nonlinear effects will counteract each other.
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| 42. |
- Johansson, Ann-Christine, et al.
(författare)
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Characterization of pyrolysis products produced from different Nordic biomass types in a cyclone pilot plant
- 2016
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Ingår i: Fuel processing technology. - : Elsevier. - 0378-3820 .- 1873-7188. ; 146, s. 9-19
-
Tidskriftsartikel (refereegranskat)abstract
- Pyrolysis is a promising thermochemical technology for converting biomass to energy, chemicals and/or fuels. The objective of the present paper was to characterize fast pyrolysis products and to study pyrolysis oil fractionation. The products were obtained from different Nordic forest and agricultural feedstocks in a pilot scale cyclone pyrolysis plant at three different reactor temperatures. The results show that the main elements (C, H and O) and chemical compositions of the products produced from stem wood, willow, forest residue and reed canary grass are in general terms rather similar, while the products obtained from bark differ to some extent. The oil produced from bark had a higher H/Ceff ratio and heating value which can be correlated to a higher amount of pyrolytic lignin and extractives when compared with oils produced from the other feedstocks. Regardless of the original feedstock, the composition of the different pyrolysis oil fractions (condensed and aerosol) differs significantly from each other. However this opens up the possibility to use specifically selected fractions in targeted applications. An increased reactor temperature generally results in a higher amount of water and water insoluble material, primarily as small lignin derived oligomers, in the produced oil.
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| 43. |
- Leineweber, Constanze, et al.
(författare)
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Work environment risk factors for the duration of all cause and diagnose-specific sickness absence among healthcare workers in Sweden : a prospective study
- 2020
-
Ingår i: Occupational and Environmental Medicine. - : BMJ. - 1351-0711 .- 1470-7926. ; 77:11, s. 782-789
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives Increasing sickness absence (SA) has been reported among healthcare workers in Sweden. Our aim was to analyse the impact of work environment factors on short-term and long-term SA based on musculoskeletal and psychiatric diagnoses among healthcare workers.Methods The study sample consisted of healthcare workers (n=12 452) drawn from representative samples of workers aged 16 to 64, who participated in the Swedish Work Environment Surveys (SWES) between 1993 and 2013. The outcomes were either short-term (<= 28 days) or long-term (>104 days) SA between 1994 and 2016. HRs and 95% CIs were calculated for the impact of physical and psychosocial working conditions on risk of subsequent short-term or long-term SA for 3 years after participation in SWES.Results Heavy physical work and strenuous work postures showed elevated HRs for short-term and long-term SA compared with those without these work exposures. Similarly, high job demands and low job control each increased the risk for both short-term and long-term SA compared with employees with low job demands and high job control. Low job support increased the risk for short-term SA compared with those with high job support. Working conditions were strongly related to short-term SA due to musculoskeletal diagnoses but not to short-term SA due to psychiatric diagnoses. None of the work characteristics, except strenuous postures, elevated the risk for long-term SA due to psychiatric diagnosis compared with employees without these characteristics.Conclusions Ergonomic improvements and stress reduction among healthcare workers are likely to reduce the prevalence of SA foremost due to musculoskeletal diagnoses.
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| 44. |
- Marklund, Bertil, 1945, et al.
(författare)
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Referrals of dyspeptic self-care patients from pharmacies to physicians, supported by clinical guidelines.
- 2003
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Ingår i: Pharmacy world & science : PWS. - 0928-1231. ; 25:4, s. 168-172
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: It is important that self-medication customers with potentially serious diseases are correctly referred from pharmacies to physicians. The aim of this study was to determine the appropriateness of pharmacy practitioners in referring customers suffering from dyspepsia to a general practitioner (GP). METHOD: Practitioners in 12 pharmacies, supported by clinical guidelines and training, recorded information regarding the dyspeptic customers they referred to a physician on a data collection card. The card was sent to a GP participating in the study, who did a regular medical history of the referred customer over the phone and assessed whether the referral was appropriate or not. RESULTS: Out of 133 referred customers with dyspepsia, 132 completed the study. The GPs found that 119 (90%) needed a medical examination and/or prescription drugs and thus assessed these referrals as appropriate. In three cases (2%) the referral was doubtful and in ten cases (8%) not adequate, as the symptoms were more likely to come from an irritable bowel syndrome than dyspepsia. CONCLUSION: The results confirm the role of pharmacy practitioners as important members of the primary health care team. Provided with the appropriate referral guidelines and training, they are in a position to operate as 'filters', promoting the adequate use of other primary care services
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| 45. |
- Marklund, Emil, et al.
(författare)
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DNA surface exploration and operator bypassing during target search
- 2020
-
Ingår i: Nature. - : NATURE RESEARCH. - 0028-0836 .- 1476-4687. ; 583:7818, s. 858-
-
Tidskriftsartikel (refereegranskat)abstract
- Many proteins that bind specific DNA sequences search the genome by combining three-dimensional diffusion with one-dimensional sliding on nonspecific DNA(1-5). Here we combine resonance energy transfer and fluorescence correlation measurements to characterize how individual lac repressor (LacI) molecules explore the DNA surface during the one-dimensional phase of target search. To track the rotation of sliding LacI molecules on the microsecond timescale, we use real-time single-molecule confocal laser tracking combined with fluorescence correlation spectroscopy (SMCT-FCS). The fluctuations in fluorescence signal are accurately described by rotation-coupled sliding, in which LacI traverses about 40 base pairs (bp) per revolution. This distance substantially exceeds the 10.5-bp helical pitch of DNA; this suggests that the sliding protein frequently hops out of the DNA groove, which would result in the frequent bypassing of target sequences. We directly observe such bypassing using single-molecule fluorescence resonance energy transfer (smFRET). A combined analysis of the smFRET and SMCT-FCS data shows that LacI hops one or two grooves (10-20 bp) every 200-700 mu s. Our data suggest a trade-off between speed and accuracy during sliding: the weak nature of nonspecific protein-DNA interactions underlies operator bypassing, but also speeds up sliding. We anticipate that SMCT-FCS, which monitors rotational diffusion on the microsecond timescale while tracking individual molecules with millisecond resolution, will be applicable to the real-time investigation of many other biological interactions and will effectively extend the accessible time regime for observing these interactions by two orders of magnitude. Single-molecule fluorescence resonance energy transfer and real-time confocal laser tracking with fluorescence correlation spectroscopy together characterize how individual lac repressor molecules bypass operator sites while exploring the DNA surface at microsecond timescales.
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| 46. |
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| 47. |
- Marklund, Emil, et al.
(författare)
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Mechanism of DNA surface exploration and operator bypassing during target search
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Many proteins that bind specific DNA sequences search the genome by combining three dimensional (3D) diffusion in the cytoplasm with one dimensional (1D) sliding on non-specific DNA. Here we combine resonance energy transfer and fluorescence correlation measurements to characterize how individual lac repressor (LacI) molecules explore DNA during the 1D phase of target search. To track the rotation of sliding LacI molecules on the microsecond time scale during DNA surface search, we use real-time single-molecule confocal laser tracking combined with fluorescence correlation spectroscopy (SMCT-FCS). The fluorescence signal fluctuations are accurately described by rotation-coupled sliding, where LacI traverses ~40 base pairs (bp) per revolution. This distance substantially exceeds the 10.5-bp helical pitch of DNA, suggesting that the sliding protein frequently hops out of the DNA groove, which would result in frequent bypassing of target sequences. Indeed, we directly observe such bypassing by single-molecule fluorescence resonance energy transfer (smFRET). A combined analysis of the smFRET and SMCT-FCS data shows that LacI at most hops one to two grooves (10-20 bp) every 250 μs. Overall, our data suggest a speed-accuracy trade-off during sliding; the weak nature of non-specific protein-DNA interactions underlies operator bypassing but also facilitates rapid sliding. We anticipate that our SMCT-FCS method to monitor rotational diffusion on the microsecond time scale while tracking individual molecules with millisecond time resolution will be applicable to the real-time investigation of many other biological interactions and effectively extends the accessible time regime by two orders of magnitude.
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| 48. |
- Marklund, Magnus, et al.
(författare)
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A self-consisted CFD-model for pressurized high temperature black liquor gasification
- 2008
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Ingår i: IFRF Combustion Journal. - 1562-479X. ; , s. 1-34, s. 1-34
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Tidskriftsartikel (refereegranskat)abstract
- High temperature pressurised black liquor gasification has the potential to significantly improve the efficiency of energy and chemical recovery in the pulping industry. However, a lack of demonstration of the reliability of the process has delayed its large scale industrial implementation. As an important step towards a greater trust in the process reliability, a self-consistent CFD model has been developed. This paper contains a detailed description of the model and a performance prediction of an entrained flow pilot gasifier for a typical operational condition. Emphasis is put on the modelling of input data for the CFD simulation where eight key assumptions form the basis for a consistent model of the black liquor composition. The results for the pilot gasifier performance with typical values for the design variables indicate that the droplet size should be
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| 49. |
- Marklund, Magnus, et al.
(författare)
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Approximate modelling of the flow of gas and droplets in an entrained flow pressurised black liquor gasification reactor
- 2001
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Ingår i: Proceedings of the 2001 International Joint Power Generation Conference. - New York : American Society of Mechanical Engineers. - 791835391 ; , s. 385-393
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Konferensbidrag (refereegranskat)abstract
- The development of an approximate model to study pressurized gasification of black liquor in an integrated combined cycle configuration is analyzed. Black liquor, an useful fuel in the paper industry, is obtained as a by-product of the papermaking processes. In the entrained flow gasification process, black liquor is atomized in a burner nozzle and partially combusted in a cylindrical reactor to form a combustible fuel gas and a molten smelt of alkali salts. The gasification process causes increased control of the fate of sulfur and sodium in the process, used to improve the pulp yield and mill quality. The limitation of the model is that the distribution of mass transfer from droplets to the gas phase must be prescribed.
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| 50. |
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