| 1. |
- Moberg, Christina, et al.
(författare)
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De unga gör helt rätt när de stämmer staten
- 2022
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Ingår i: Aftonbladet. - 1103-9000.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- 1 620 forskare och lärare i forskarvärlden: Vi ställer oss bakom Auroras klimatkrav
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| 2. |
- Baghdadchi, Amir, 1994-, et al.
(författare)
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Promoting austenite formation in laser welding of duplex stainless steel-impact of shielding gas and laser reheating
- 2021
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Ingår i: Welding in the World. - : Springer Science and Business Media LLC. - 0043-2288 .- 1878-6669. ; 65, s. 499-511
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Tidskriftsartikel (refereegranskat)abstract
- Avoiding low austenite fractions and nitride formation are major challenges in laser welding of duplex stainless steels (DSS). The present research aims at investigating efficient means of promoting austenite formation during autogenous laser welding of DSS without sacrificing productivity. In this study, effects of shielding gas and laser reheating were investigated in welding of 1.5-mm-thick FDX 27 (UNS S82031) DSS. Four conditions were investigated: Ar-shielded welding, N2-shielded welding, Ar-shielded welding followed by Ar-shielded laser reheating, and N2-shielded welding followed by N2-shielded laser reheating. Optical microscopy, thermodynamic calculations, and Gleeble heat treatment were performed to study the evolution of microstructure and chemical composition. The austenite fraction was 22% for Ar-shielded and 39% for N2-shielded as-welded conditions. Interestingly, laser reheating did not significantly affect the austenite fraction for Ar shielding, while the austenite fraction increased to 57% for N2-shielding. The amount of nitrides was lower in N2-shielded samples compared to in Ar-shielded samples. The same trends were also observed in the heat-affected zone. The nitrogen content of weld metals, evaluated from calculated equilibrium phase diagrams and austenite fractions after Gleeble equilibrating heat treatments at 1100 °C, was 0.16% for N2-shielded and 0.11% for Ar-shielded welds, confirming the importance of nitrogen for promoting the austenite formation during welding and especially reheating. Finally, it is recommended that combining welding with pure nitrogen as shielding gas and a laser reheating pass can significantly improve austenite formation and reduce nitride formation in DSS laser welds. © 2020, The Author(s).
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| 3. |
- Björner Brauer, Hanna, et al.
(författare)
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Pain Relieving Light - (How) Is it Possible?
- 2024. - 1
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Ingår i: IOP Science home Accessibility Help Journals Books Publishing Support Login IOP Conference Series: Earth and Environmental Science. - 1755-1307. ; 1320
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Konferensbidrag (refereegranskat)abstract
- About 15% of the population suffer from migraines and it is estimated that about 40% of all people with migraines would benefit from preventive treatment, but only 3-13% use it. Migraine is a huge burden for society and individuals. Migraines can be intensified by light, and some patients need to stay in a dark room until the attack is over. People with this type of photosensitivity show a clear preference for light color, specifically green, which has been shown to be more comfortable and even pain relieving in some cases. We will present a feasibility study with the aim of preparing a series of experiments to investigate if regular short-term green-light-exposure can prevent migraines. We will present findings from the literature, developed light equipment, and plans for future testing of migraine friendly light solutions.
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| 4. |
- Churakov, Mikhail, et al.
(författare)
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Milk fatty acids as indicators of negative energy balance of dairy cows in early lactation
- 2021
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Ingår i: Animal. - : Elsevier BV. - 1751-7311 .- 1751-732X. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Most dairy cows experience negative energy balance (NEB) in early lactation because energy demand for milk synthesis is not met by energy intake. Excessive NEB may lead to metabolic disorders and impaired fertility. To optimize herd management, it is useful to detect cows in NEB in early lactation, but direct calculation of NEB is not feasible in commercial herds. Alternative methods rely on fat-to-protein ratio in milk or on concentrations of non-esterified fatty acids (NEFA) and β-hydroxybutyrate (BHB) in blood. Here, we considered methods to assess energy balance (EB) of dairy cows based on the fatty acid (FA) composition in milk. Short- and medium-chain FAs (primarily, C14:0) are typically synthesized de novo in the mammary gland and their proportions in milk fat decrease during NEB. Long-chain FAs C18:0 and C18:1 cis-9 are typically released from body fat depots during NEB, and their proportions increase. In this study, these FAs were routinely determined by Fourier-transform infrared spectroscopy (FTIR) of individual milk samples. We performed an experiment on 85 dairy cows in early lactation, fed the same concentrate ration of up to 5 kg per day and forage ad libitum. Daily milk yield and feed intake were automatically recorded. During lactation weeks 2, 4, and 6 after calving, two milk samples were collected for FTIR spectroscopy, Tuesday evening and Wednesday morning, blood plasma samples were collected Thursday morning. Net energy content in feed and net energy required for maintenance and lactation were estimated to derive EB, which was used to compare alternative indicators of severe NEB. Linear univariate models for EB based on NEFA concentration (deviance explained = 0.13) and other metabolites in blood plasma were outperformed by models based on concentrations of metabolites in milk: fat (0.27), fat-to-protein ratio (0.18), BHB (0.20), and especially C18:0 (0.28) and C18:1 cis-9 (0.39). Analysis of generalized additive models (GAM) revealed that models based on milk variables performed better than those based on blood plasma (deviance explained 0.46 vs. 0.21). C18:0 and C18:1 cis-9 also performed better in severe NEB prediction for EB cut-off values ranging from −50 to 0 MJ NEL/d. Overall, concentrations of C18:0 and C18:1 cis-9 in milk, milk fat, and milk BHB were the best variables for early detection of cows in severe NEB. Thus, milk FA concentrations in whole milk can be useful to identify NEB in early-lactation cows.
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| 5. |
- Holtstam, Dan, 1963-, et al.
(författare)
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Garpenbergite, Mn6□As5+Sb5+O10(OH)2, a new mineral related to manganostibite, from the Garpenberg Zn–Pb–Ag deposit, Sweden
- 2022
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Ingår i: Mineralogical magazine. - : Mineralogical Society. - 0026-461X .- 1471-8022. ; 86:1, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- Garpenbergite is a new mineral (IMA2020-099) from the Garpenberg Norra mine, Hedemora, Dalarna, Sweden. It occurs with carlfrancisite and minor stibarsen, paradocrasite and filipstadite in a fractured skarn matrix of granular jacobsite, alleghanyite, kutnohorite and dolomite. Crystals are short-prismatic, up to 1.5 mm in length. They have a blackish to greyish brown colour, and are lustrous semi-opaque, with brown streak. Garpenbergite is brittle, with an uneven to subconchoidal fracture. Cleavage is distinct on {010}. Hardness ≈ 5 (Mohs) and VHN100 = 650(40). Dcalc = 4.47(1) g⋅cm−3 , overall ncalc = 1.85. Maximum specular reflectance values (%) obtained are 9.2 (470 nm), 9.1 (546 nm), 9.0 (589 nm) and 8.9 (650 nm). The empirical chemical formula of garpenbergite, based on electron microprobe data, is (Mn2+3.97Mg1.48Mn3+0.26Zn0.29)Σ6.00(As0.89Fe3+0.04Mn3+0.06Si0.01)Σ1.00(Sb0.98Fe0.02)Σ1.00O10[(OH)1.99Cl0.01]Σ2.00. The five strongest Bragg peaks in the powder X-ray diffraction pattern [d, Å(I, %) (hkl)] are 3.05 (30) (002), 2.665 (100) (161), 2.616 (40) (301), 2.586 (25) (251) and 1.545 (45) (462). The orthorhombic unit-cell dimensions (in Å) are a = 8.6790(9), b = 18.9057(19) and c = 6.1066(6), with V = 1001.99(18) Å3 for Z = 4. The crystal structure was refined from single-crystal X-ray diffraction data in the space-group Ibmm to R1 = 3.7% for 957 reflections. Garpenbergite, ideally Mn6As5+Sb5+O10(OH)2, is isostructural with manganostibite, Mn7AsSbO12, but possesses a cation vacancy (□) at an octahedrally coordinated structural site; the two minerals are thus related by the exchange Mn2+ + 2O2– → □ + 2(OH)– . The presence of hydroxyl groups is supported by vibration bands at 3647 and 3622 cm−1 in the Raman spectrum of garpenbergite, and by bond-valence considerations.
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| 6. |
- Hosseini, Vahid, 1987-, et al.
(författare)
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A physical simulation technique for cleaner and more sustainable research in additive manufacturing
- 2021
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Ingår i: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526 .- 1879-1786. ; 285
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Tidskriftsartikel (refereegranskat)abstract
- Additive manufacturing (AM) introduces a new domain for zero waste and cleaner production. Research for verification of materials in AM and effects of the process on the material behavior, however, demands a significant amount of materials, energy, and man-hours. The design of suitable physical simulation techniques that can duplicate complex AM thermal cycles without performing AM is therefore crucial for cleaner and more sustainable AM research. This paper aims at introducing a novel technique to reproduce AM thermal cycles in a controlled way on a small sample, thereby supporting sustainable alloy verification and cleaner research. In this technique, a stationary arc is applied to a disc-shaped sample mounted on a water-cooled chamber, where the arc and water provide rapid heating and cooling, respectively. In the present study, a super duplex stainless steel (SDSS) was used as the experimental alloy to simulate the evolution of microstructure and properties during wire-arc additive manufacturing. The experiment was performed using the stationary arc with the holding time of 5 s, applied 1, 5, or 15 times. The total processing time was only 450 s (7.5 min) for the 15 a.m. thermal cycles experiment. The SDSS showed a progressive increase in the austenite fraction at 600–1200 °C and the formation of detrimental sigma phase at 700–1000 °C, but a reduction of austenite fraction above 1300 °C. The results were in good agreement with the literature, verifying the applicability of the physical simulation technique for AM research. Calculations showed that using arc heat treatment as the initial step is 6–20 times more efficient in different respects (materials, energy, and man-hours) compared to wire arc additive manufacturing. Therefore, this methodology can be implemented to gain an understanding of materials in AM applications thereby eliminating the need for investments in additive manufacturing of a specific component. © 2020
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| 7. |
- Hosseini, Vahid, 1987-, et al.
(författare)
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Bead by bead study of a multipass shielded metal arc-welded super-duplex stainless steel
- 2020
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Ingår i: Welding in the World. - : Springer Science and Business Media LLC. - 0043-2288 .- 1878-6669. ; 64:2, s. 283-299
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Tidskriftsartikel (refereegranskat)abstract
- The present study aims at investigating bead geometry and the evolution of microstructure with thermal cycles in multipass shielded metal arc welding of a V-groove 13-mm type-2507 super-duplex stainless steel (SDSS) plate. The weld consisted of 4 beads produced with arc energies of 0.81-1.06 kJ/mm. The upper beads showed lower base metal (BM) dilution than the first bead. Thermal cycles were recorded with thermocouples, indicating that the cooling rate decreased in the as-deposited weld zone when adding a new bead. Ferrite fraction in the as-welded condition was lower for the upper beads. The austenite grain morphology in reheated passes varied depending on the local peak temperatures and the number of reheating passes. Sigma phase precipitated in a location reheated by the third and fourth passes that was subjected to a critical peak temperature for sigma precipitation. Ferrite content, measured using image analysis and Fisher FERITSCOPE technique, showed that the ferrite fraction moved toward 50/50% in the weld metal with an increasing number of reheating cycles. Finally, a schematic map showing an overview of the microstructure in the multipass SDSS weld was introduced.
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| 8. |
- Hosseini, Vahid, 1987-, et al.
(författare)
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Precipitation kinetics of Cu-rich particles in super duplex stainless steels
- 2021
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Ingår i: Journal of Materials Research and Technology. - : Elsevier BV. - 2238-7854. ; 15, s. 3951-3964
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Tidskriftsartikel (refereegranskat)abstract
- Complex precipitation behavior of Cu-rich particles (CRPs) was investigated and simulated in continuously cooled and quench-aged super duplex stainless steel. Atom probe tomography (APT) and scanning electron microscopy showed that slow cooling resulted in nonuniform multimodal CRP precipitation and spinodal decomposition, while in the fast cooled and quench-aged conditions, more uniform precipitation of CRPs with no visible spinodal decomposition was found. Depletion of Cu, Ni, and Mn was observed in the ferrite next to the CRPs during growth, but not during dissolution. Some evidence of Ostwald ripening was seen after slow cooling, but in the quench-aged condition, particle coalescence was observed. Large CRPs disappeared next to a ferrite–austenite phase boundary after slow cooling when Cu was depleted due to the diffusion to austenite as also predicted by moving boundary Dictra simulation. Comparing Cu depleted areas next to CRPs analyzed by APT and moving boundary Dictra simulation of CRP–ferrite showed that the effective Cu diffusion coefficient during the early-stage precipitation was about 300 times higher than the Cu diffusion coefficient in ferrite at 475 °C. Using the effective diffusion coefficient and a size-dependent interfacial energy equation, CRP size distribution was successfully predicted by the Langer–Schwartz model implemented in Thermo-Calc Prisma. Applying a short aging time and continuous cooling increased the hardness and decreased the toughness values compared to the solution annealed condition. A nonuniform distribution of Cu in ferrite, the duplex structure, and partitioning of alloying elements among different phases are factors making CRP precipitation in duplex stainless steels complex.
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| 9. |
- Karlsson, Johanna, et al.
(författare)
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Feed intake, milk yield and metabolic status of early-lactation Swedish Holstein and Swedish Red dairy cows of different parities fed grass silage and two levels of byproduct-based concentrate
- 2020
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Ingår i: Livestock Science. - : Elsevier BV. - 1871-1413 .- 1878-0490. ; 242
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Tidskriftsartikel (refereegranskat)abstract
- Dairy cows can produce highly nutritive food products (milk, meat etc.) from fibrous feed e.g. grass and different byproducts from the food and fuel industry, that cannot be consumed directly by humans. However, as there are limited amounts of byproducts available, decreasing the amount of byproduct-based concentrate in the diet could be a strategy for improving sustainability within dairy production if high milk production should be maintained. In this study, 26 multiparous (n = 14) and primiparous (n = 12) dairy cows of the breeds Swedish Red (n = 14) and Swedish Holstein (n = 12) were followed between lactation weeks 1 and 6. They were fed either a low-concentrate (n = 13; LC) or high-concentrate (n = 13; HC) byproduct-based (sugar beet pulp, rapeseed meal, distiller's grain, wheat bran) ration, in combination with highly digestible grass-clover silage ad libitum. To achieve similar concentrate intake per kg body weight in primiparous and multiparous cows, multiparous cows were offered 5 kg concentrate on the LC diet and 15 kg concentrate on the HC diet, while primiparous cows were offered 4 kg concentrate on the LC diet and 14 kg concentrate on the HC diet as target concentrate rations. We found no overall differences in dry matter intake, energy-corrected milk yield, energy balance, blood plasma metabolites, blood hormones or milk fatty acids between cows on the LC and HC diets. However, HC cows had a higher yield of ECM in lactation week 6 and gained body weight compared with LC cows. As expected, multiparous cows had higher dry matter intake and energy-corrected milk yield, but we found no difference in energy balance between parities. However, multiparous cows lost more body condition and had higher blood plasma concentrations of non-esterified fatty acids, indicating that they used more body tissue to support milk production. In conclusion, both multiparous and primiparous Swedish Red and Swedish Holstein dairy cows seem able to adapt to low-concentrate diets in early lactation when the diets are based on byproducts and grass-clover silage, providing the potential to increase sustainability in dairy production.
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| 10. |
- Karlsson, Johanna, et al.
(författare)
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Full-lactation performance of multiparous dairy cows with differing residual feed intake
- 2022
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 17
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Tidskriftsartikel (refereegranskat)abstract
- Residual feed intake (RFI) is an efficiency trait underpinning profitability and environmental sustainability in dairy production. This study compared performance during a complete lactation of 36 multiparous dairy cows divided into three equal-sized groups with high (HRFI), intermediate (IRFI) or low RFI (LRFI). Residual feed intake was determined by two different equations. Residual feed intake according to the NorFor system was calculated as (RFINorFor) = (NEintake)–(NEmaintenance + NEgestation + NEmilk—NEmobilisation + NEdeposition). Residual feed intake according to the USA National Research Council (NRC) (RFINRC) was calculated as: RFI = DMI − predicted DMI where predicteds DMI = [(0.372× ECM)+(0.0968×BW0.75)]×(1−e−0.192×(DIM/7+3.67)). Cows in the HRFINorFor group showed higher daily CH4 production, CH4/ECM and CH4 yield (g/kg DMI) than IRFINorFor and LRFINorFor cows. Cows characterized by high efficiency (LRFINorFor) according to the NorFor system had lower body weight. Dry matter intake and apparent dry matter digestibility were not affected by efficiency group but milk yield was lower in the low efficiency, HRFINorFor, group. Cows characterized by high efficiency according to the NRC system (LRFINRC) had lower dry matter intake while yield of CH4 was higher. Daily CH4 production and CH4 g/kg ECM did not differ between RFINRC groups. Dairy cows characterized by high efficiency (both LRFINorFor and LRFINRC cows) over a complete lactation mobilized more of their body reserves in early lactation as well as during the complete lactation. The results also indicated great phenotypic variation in RFI between different stages the lactation.
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| 11. |
- Karlsson, Johanna, et al.
(författare)
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Whole-lactation feed intake, milk yield, and energy balance of Holstein and Swedish Red dairy cows fed grass-clover silage and 2 levels of byproduct-based concentrate
- 2020
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Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 103, s. 8922-8937
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Tidskriftsartikel (refereegranskat)abstract
- Ruminants can produce meat and milk from fibrous feed and byproducts not suitable for human consumption. However, high-yielding dairy cows are generally fed a high proportion of cereal grain and pulses, which could be consumed directly by humans. If high production of dairy cows could be maintained with ingredients of low human interest, the sustainability of dairy production would improve. In the present study, 37 multiparous [Holstein (n = 13) and Swedish Red (n = 24)] dairy cows were followed over a whole lactation. A low-concentrate diet of up to 6 kg concentrate per day (6kgConc) was fed to 27 cows, whereas 10 cows were fed a high-concentrate diet of up to 12 kg concentrate per day (12kgConc). The concentrate was mainly based on byproducts (sugar beet pulp, wheat bran, rapeseed meal, distiller's grain). Grass-clover silage of high digestibility was offered ad libitum. Over the whole lactation, cows on the 6kgConc diet had lower dry matter intake and higher forage intake than cows on the 12kgConc diet. Milk yield and energy balance were not influenced by dietary treatment. However, the cows on the 6kgConc diet numerically produced 2.4 kg less energy-corrected milk than cows on 12kgConc diet. The study lacked the statistical power to identify treatment effects on daily yield below 2.8 kg of milk due to low number of animals per treatment. Feed efficiency (as energy-corrected milk yield/dry matter intake or residual feed intake), body weight change, body condition change, milk fatty acid concentration in total milk fatty acids, plasma nonesterified fatty acids, glucose, beta-hydroxybutyrate, and fertility measurements were not affected by diet, supporting the energy balance results. However, higher plasma concentrations o f insulin-like growth factor-1 and insulin were observed in cows fed he 12kgConc diet. These findings show that cows can adapt to a high-forage diet virtually without humangrade ingredients, without compromising feed efficiency or energy balance, thereby contributing to sustainable food production.
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| 12. |
- Lidén, Edvard, et al.
(författare)
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Metabolic syndrome - a risk factor for all-cause disability pension : a prospective study based on the Swedish WOLF cohort
- 2020
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Ingår i: Scandinavian Journal of Work, Environment and Health. - : Nordic Association of Occupational Safety and Health (NOROSH). - 0355-3140 .- 1795-990X. ; 46:4, s. 402-409
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The aim was to study the impact of metabolic syndrome on the risk for disability pension among Swedish employees.Methods: A working population-based prospective cohort [Work, Lipids and Fibrinogen (WOLF) cohort, N=10 803], was linked to national registry records of all-cause disability pension for the period 1992–2013. Occupational health service data included 1992–2009 anthropometric measurements, blood samples, and questionnaires. Metabolic syndrome was defined according to International Diabetes Federation criteria, and risk for any all-cause disability pension was analyzed using Cox proportional hazard regression as hazard ratios (HR) with 95% confidence intervals (CI) adjusted for age, sex and other covariates.Results: Of the employees, 17.9% (men 21.5%, women 9.7%) met the criteria for metabolic syndrome. The prevalence of all-cause disability pension was 15.2% in men with metabolic syndrome and 7.5% in men without metabolic syndrome; for women, the corresponding results were 23.2% and 12.7%. After adjustment for socio-demographic factors, health behaviors, work-related factors, diabetes, and obesity, the risk for all-cause disability pension among subjects with metabolic syndrome displayed an HR of 1.37 (95% CI 1.18–1.60). Results were similar for men and women. In a subgroup, further adjustment for chronic diseases resulted in an HR of 1.32 (95% CI 1.04–1.68).Conclusion: This study demonstrates an increased risk for all-cause disability pension, even after adjustment for other risk factors, among Swedish employees with metabolic syndrome compared to those without at baseline.
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| 13. |
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| 14. |
- McCarrick, Sarah, et al.
(författare)
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Genotoxicity and inflammatory potential of stainless steel welding fume particles : an in vitro study on standard vs Cr(VI)-reduced flux-cored wires and the role of released metals
- 2021
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Ingår i: Archives of Toxicology. - : Springer Nature. - 0340-5761 .- 1432-0738. ; 95:9, s. 2961-2975
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Tidskriftsartikel (refereegranskat)abstract
- Welders are daily exposed to various levels of welding fumes containing several metals. This exposure can lead to an increased risk for different health effects which serves as a driving force to develop new methods that generate less toxic fumes. The aim of this study was to explore the role of released metals for welding particle-induced toxicity and to test the hypothesis that a reduction of Cr(VI) in welding fumes results in less toxicity by comparing the welding fume particles of optimized Cr(VI)-reduced flux-cored wires (FCWs) to standard FCWs. The welding particles were thoroughly characterized, and toxicity (cell viability, DNA damage and inflammation) was assessed following exposure to welding particles as well as their released metal fraction using cultured human bronchial epithelial cells (HBEC-3kt, 5-100 mu g/mL) and human monocyte-derived macrophages (THP-1, 10-50 mu g/mL). The results showed that all Cr was released as Cr(VI) for welding particles generated using standard FCWs whereas only minor levels (< 3% of total Cr) were released from the newly developed FCWs. Furthermore, the new FCWs were considerably less cytotoxic and did not cause any DNA damage in the doses tested. For the standard FCWs, the Cr(VI) released in cell media seemed to explain a large part of the cytotoxicity and DNA damage. In contrast, all particles caused rather similar inflammatory effects suggesting different underlying mechanisms. Taken together, this study suggests a potential benefit of substituting standard FCWs with Cr(VI)-reduced wires to achieve less toxic welding fumes and thus reduced risks for welders.
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| 15. |
- Ntallaris, Theodoros, et al.
(författare)
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Milk fatty acids as indicators of delayed commencement of luteal activity in dairy cows in early lactation
- 2023
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Ingår i: Reproduction in Domestic Animals. - : Wiley. - 0936-6768 .- 1439-0531. ; 58, s. 500-510
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Tidskriftsartikel (refereegranskat)abstract
- Excessive mobilization of adipose reserves due to severe negative energy balance in early lactation may be detrimental to dairy cow fertility at individual and herd level. Reproductive efficiency is one of the main factors influencing herd profitability and a strategy for early detection and management of cows with delayed resumption of cyclicity will result higher conception rate, decreased proportion of cows with extended lactation, fewer inseminations per conception and lower culling rates due to reproductive disorders. Using two groups of dairy cows (Holstein n = 37, Swedish Red breed [SRB] n = 49), we investigated potential differences between cows with different commencement of luteal activity (CLA) and the feasibility of using milk fatty acids (MFAs) as predictors of delayed CLA. Milk samples for progesterone analysis were collected twice weekly during the first six weeks in milk. The concentrations of the MFAs C14:0, C16:0, C18:0 and C18:1 cis -9 in milk (g/100 g milk) and in milk fat (g/100 g fat) were analysed by Fourier transform infrared spectroscopy and individual MFA profiles were calculated by weeks in milk. Commencement of luteal activity was defined as the first day with milk progesterone concentrations > 3 ng/ml at two successive measurements. The study population was categorized as early (n = 42) or late (n = 44) CLA, using the median value of 21 DIM as the cut -off. Analysis of the data revealed that CLA was correlated with the proportion of some specific MFAs, where cows with delayed CLA had lower IGF-1 (92.9 +/- 7.9 vs. 114.1 +/- 7.9 ng/ml; p = .05) and C14:0 levels (10.4 +/- 0.2 vs. 11.5 +/- 0.2 g/100 fat; p < .01) and higher C18:0 (9.6 +/- 0.2 vs. 8.9 +/- 0.6 g/100 fat; p < .01) and C18:1 cis -9 levels (24.9 +/- 0.4 vs. 23.5 +/- 0.4 g/100 fat; p < .05). Delayed CLA (mean 34 days) was predictable for approximately 80% of cows based on C18:0 or C18:1 cis -9 concentrations in week 2 postpartum. Overall, MFAs (C18:0 and C18:1 cis -9) as biomarkers were better indicators than betahydroxybutyrate or non-esterified fatty acids in early detection of cows with delayed or normal CLA. The MFA concentrations in milk samples from cows in early lactation can thus be used as a non-invasive method to identify cows at risk of delayed CLA, acting as potential biomarkers for future reproductive performance.
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| 16. |
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| 17. |
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| 18. |
- Schenk, Jonathan, 1992-, et al.
(författare)
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Methane in Lakes : Variability in Stable Carbon Isotopic Composition and the Potential Importance of Groundwater Input
- 2021
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Ingår i: Frontiers in Earth Science. - Lausanne, Switzerland : Frontiers Media S.A.. - 2296-6463. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Methane (CH4) is an important component of the carbon (C) cycling in lakes. CH4 production enables carbon in sediments to be either reintroduced to the food web via CH4 oxidation or emitted as a greenhouse gas making lakes one of the largest natural sources of atmospheric CH4. Large stable carbon isotopic fractionation during CH4 oxidation makes changes in 13C:12C ratio (δ13C) a powerful and widely used tool to determine the extent to which lake CH4 is oxidized, rather than emitted. This relies on correct δ13C values of original CH4 sources, the variability of which has rarely been investigated systematically in lakes. In this study, we measured δ13C in CH4 bubbles in littoral sediments and in CH4 dissolved in the anoxic hypolimnion of six boreal lakes with different characteristics. The results indicate that δ13C of CH4 sources is consistently higher (less 13C depletion) in littoral sediments than in deep waters across boreal and subarctic lakes. Variability in organic matter substrates across depths is a potential explanation. In one of the studied lakes available data from nearby soils showed correspondence between δ13C-CH4 in groundwater and deep lake water, and input from the catchment of CH4 via groundwater exceeded atmospheric CH4 emissions tenfold over a period of 1 month. It indicates that lateral hydrological transport of CH4 can explain the observed δ13C-CH4 patterns and be important for lake CH4 cycling. Our results have important consequences for modelling and process assessments relative to lake CH4 using δ13C, including for CH4 oxidation, which is a key regulator of lake CH4 emissions.
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| 19. |
- Tarekegn, Getinet Mekuriaw, et al.
(författare)
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Genetic parameters of forage dry matter intake and milk produced from forage in Swedish Red and Holstein dairy cows
- 2021
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Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 104, s. 4424-4440
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Tidskriftsartikel (refereegranskat)abstract
- High-yielding dairy cows are often fed high proportions of cereal grain and pulses. For several reasons, it would be desirable to replace these feed sources with forage, which is not suitable for human consumption. Feeding large amounts of forage to dairy cows could also make dairy production more publicly acceptable in the future. In this study, we estimated genetic parameters for total dry matter intake (DMI), DMI from forage (DMIFor), energy-corrected milk (ECM), and ECM produced from forage (ECMFor). A total of 1,177 lactations from 575 cows of Swedish Red (SR) and Holstein (HOL) dairy breeds were included in the study. Mixed linear animal random regression models were used, with fixed effect of calving season and lactation week nested within parity 1 and 2+, fixed effect of calving year, and random regression coefficients for breeding value (up to linear) and permanent environmental effect (up to quadratic) of the cow. Heritability for DMI and DMIFor was generally higher for HOL than for SR in all-parity data and in later parities; however, the opposite was true for first parity. Heritability for DMI and DMIFor during the first 8 wk averaged 0.11 and 0.15, respectively, in all-parity data for the 2 breeds. Corresponding values for ECMFor and ECM were 0.21 and 0.29, respectively. In first parity, values were 0.32, 0.36, 0.28, and 0.51, respectively. The genetic correlation between DMI and DMIFor was high, above 0.83, and fairly constant across the lactation. The genetic correlation between ECMFor and ECM was close to unity in the later part of lactation for both breeds, but was around 0.8 in the early lactation for both breeds; it decreased for HOL to 0.54 in wk 17. The genetic correlations between DMI and ECMFor and between DMIFor and ECMFor were low and negative for HOL (absolute value similar to 0.2-0.3), but changed for SR from weakly positive in early lactation to negative values and back to positive toward the end of lactation. For most traits, the correlation between wk 1 and wk 8 into the lactation was very high; the lowest value was for DMI in HOL at 0.81. The genetic correlation between parities was rather high in the first part of the lactation. During the first 8 wk, the correlation was lower for HOL than for SR, except for ECM. We found that DMIFor and ECMFor showed reasonably large heritability, and future work should explore the possibility of genomic evaluations.
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| 20. |
- Valiente Bermejo, María Asunción, 1972-, et al.
(författare)
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Exposure of FeCrAl Overlay Welds on Superheater Tubes : Influence of Local Environment on Degradation
- 2022
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Ingår i: Journal of Failure Analysis and Prevention. - : Springer. - 1547-7029 .- 1864-1245. ; 22:1, s. 400-408
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Tidskriftsartikel (refereegranskat)abstract
- Two experimental FeCrAl alloy overlay welds on tube shields were exposed in the superheater of a full-size waste fired boiler for 6 months. The tube shields were in different tube lines and positions within the superheater chamber to investigate possible heterogeneities in the exposure environment. The visual inspection of the exposed tube shields and the corrosion-erosion rates calculated from the analysis of cross-sections showed that the mid-length roof location experienced the most aggressive environment. The compositional differences between the two experimental alloys were not found to be determinant in their performance under these specific exposure conditions. It was concluded that erosion had a decisive influence on the results. The identification of local differences within the superheater chamber is important when deciding on the material selection for the different areas and locations to be protected. The output of this study is therefore interesting for further design consideration of superheaters as well as for future planning of exposures.
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| 21. |
- Valiente Bermejo, María Asunción, 1972-, et al.
(författare)
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Welding of Large Thickness Super Duplex Stainless Steel : Microstructure and Properties
- 2021
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Ingår i: METALS. - : MDPI. - 2075-4701. ; 11:8
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Tidskriftsartikel (refereegranskat)abstract
- In this study, Submerged Arc Welding (SAW) and Gas Metal Arc Welding (GMAW) processes were used in multi-pass welding of 33 mm thickness super duplex stainless steel plates. Recommended and higher than recommended arc energy and interpass temperatures were used. Both GMAW and SAW processes were able to produce large thickness weldments meeting the microstructural, mechanical, and corrosion resistance requirements, and also when using higher than recommended arc energy and interpass temperature. It was possible to reduce the number of welding passes by half when using higher than recommended arc energy and interpass temperature. The SAW process needed only half of the welding time required for the GMAW process to produce a weldment with nearly the same number of weld passes, when using recommended arc energy and interpass temperature. Based on the results of this investigation, the practical recommendations for welding large thicknesses should be revised and updated.
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