| 21. |
- Legge, Alexandra, et al.
(författare)
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Prediction of Damage Accrual in Systemic Lupus Erythematosus Using the Systemic Lupus International Collaborating Clinics Frailty Index
- 2020
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Ingår i: Arthritis and Rheumatology. - : Wiley. - 2326-5191 .- 2326-5205. ; 72:4, s. 658-666
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The Systemic Lupus International Collaborating Clinics (SLICC) frailty index (FI) has been shown to predict mortality, but its association with other important outcomes is unknown. We examined the association of baseline SLICC FI values with damage accrual in the SLICC inception cohort. Methods: The baseline visit was defined as the first visit at which both organ damage (SLICC/American College of Rheumatology Damage Index [SDI]) and health-related quality of life (Short Form 36) were assessed. Baseline SLICC FI scores were calculated. Damage accrual was measured by the increase in SDI between the baseline assessment and the last study visit. Multivariable negative binomial regression was used to estimate the association between baseline SLICC FI values and the rate of increase in the SDI during follow-up, adjusting for relevant demographic and clinical characteristics. Results: The 1,549 systemic lupus erythematosus (SLE) patients eligible for this analysis were mostly female (88.7%) with a mean ± SD age of 35.7 ± 13.3 years and a median disease duration of 1.2 years (interquartile range 0.9–1.5 years) at baseline. The mean ± SD baseline SLICC FI was 0.17 ± 0.08. Over a mean ± SD follow-up of 7.2 ± 3.7 years, 653 patients (42.2%) had an increase in SDI. Higher baseline SLICC FI values (per 0.05 increase) were associated with higher rates of increase in the SDI during follow-up (incidence rate ratio [IRR] 1.19 [95% confidence interval 1.13–1.25]), after adjusting for age, sex, ethnicity/region, education, baseline SLE Disease Activity Index 2000, baseline SDI, and baseline use of glucocorticoids, antimalarials, and immunosuppressive agents. Conclusion: Our findings indicate that the SLICC FI predicts damage accrual in incident SLE, which further supports the SLICC FI as a valid health measure in SLE.
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| 22. |
- Legge, Alexandra, et al.
(författare)
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Prediction of Hospitalizations in Systemic Lupus Erythematosus Using the Systemic Lupus International Collaborating Clinics Frailty Index
- 2022
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Ingår i: Arthritis Care and Research. - : Wiley. - 2151-464X .- 2151-4658. ; 74:4, s. 638-647
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The Systemic Lupus International Collaborating Clinics (SLICC) frailty index (FI) predicts mortality and damage accrual in systemic lupus erythematosus (SLE), but its association with hospitalizations has not been described. Our objective was to estimate the association of baseline SLICC-FI values with future hospitalizations in the SLICC inception cohort. Methods: Baseline SLICC-FI scores were calculated. The number and duration of inpatient hospitalizations during follow-up were recorded. Negative binomial regression was used to estimate the association between baseline SLICC-FI values and the rate of hospitalizations per patient-year of follow-up. Linear regression was used to estimate the association of baseline SLICC-FI scores with the proportion of follow-up time spent in the hospital. Multivariable models were adjusted for relevant baseline characteristics. Results: The 1,549 patients with SLE eligible for this analysis were mostly female (88.7%), with a mean ± SD age of 35.7 ± 13.3 years and a median disease duration of 1.2 years (interquartile range 0.9–1.5) at baseline. Mean ± SD baseline SLICC-FI was 0.17 ± 0.08. During mean ± SD follow-up of 7.2 ± 3.7 years, 614 patients (39.6%) experienced 1,570 hospitalizations. Higher baseline SLICC-FI values (per 0.05 increment) were associated with more frequent hospitalizations during follow-up, with an incidence rate ratio of 1.21 (95% confidence interval [95% CI] 1.13–1.30) after adjustment for baseline age, sex, glucocorticoid use, immunosuppressive use, ethnicity/location, SLE Disease Activity Index 2000 score, SLICC/American College of Rheumatology Damage Index score, and disease duration. Among patients with ≥1 hospitalization, higher baseline SLICC-FI values predicted a greater proportion of follow-up time spent hospitalized (relative rate 1.09 [95% CI 1.02–1.16]). Conclusion: The SLICC-FI predicts future hospitalizations among incident SLE patients, further supporting the SLICC-FI as a valid health measure in SLE.
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| 23. |
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| 24. |
- Resman, Lars, et al.
(författare)
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Components acting downstream of short day perception regulate differential cessation of cambial activity and associated responses in early and late clones of hybrid poplar
- 2010
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Ingår i: Plant Physiology. - : American Society of Plant Biologists. - 0032-0889 .- 1532-2548. ; 154:3, s. 1294-1303
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Tidskriftsartikel (refereegranskat)abstract
- Short days (SDs) in autumn induce growth cessation, bud set, cold acclimation, and dormancy in trees of boreal and temperate forests, and these responses occur earlier in northern than in southern genotypes. Nevertheless, we know little about whether this variation results from differential perception of SDs or differential downstream responses to the SD signal or a combination of the two. We compared global patterns of SD-regulated gene expression in the stems of hybrid poplar (Populus trichocarpa × Populus deltoides) clones that differ in their SD-induced growth cessation in order to address this question. The timing of cessation of cambial cell division caused by SDs differed between the clones and was coincident with the change in the pattern of expression of the auxin-regulated genes. The clones also differed in the timing of their SD-regulated changes in the transcript abundance of genes associated with cold tolerance, starch breakdown, and storage protein accumulation. By analyzing the expression of homologs of FLOWERING LOCUS T, we demonstrated that the clones differed little in their perception of SDs under the growth conditions applied but differed substantially in the downstream responses manifested in the timing and magnitude of gene expression after SD treatment. These results demonstrate the existence of factors that act downstream of SD perception and can contribute to variation in SD-regulated adaptive photoperiodic responses in trees.
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| 25. |
- Stockfelt, Marit, et al.
(författare)
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Plasma interferon-alpha protein levels during pregnancy are associated with lower birth weight in systemic lupus erythematosus
- 2024
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Ingår i: Rheumatology. - : OXFORD UNIV PRESS. - 1462-0324 .- 1462-0332.
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Tidskriftsartikel (refereegranskat)abstract
- Objectives Adverse pregnancy outcomes are more common in women with SLE compared with healthy women, but we lack prognostic biomarkers. Plasma IFN-alpha protein levels are elevated in a subgroup of pregnant women with SLE, but whether this is associated with pregnancy outcomes is unknown. We investigated the relationship between IFN-alpha, adverse pregnancy outcomes and the presence of autoantibodies in SLE pregnancy.Methods We followed 76 women with SLE prospectively. Protein levels of IFN-alpha were quantified in plasma collected in the second and third trimester with single-molecule array. Positivity for ANA and aPL antibodies was assessed during late pregnancy with multiplexed bead assay. Clinical outcomes included the adverse pregnancy outcomes small for gestational age (SGA), preterm birth and preeclampsia.Results During SLE pregnancy, women with SGA infants compared with those without had higher levels of plasma IFN-alpha protein, and IFN-alpha positivity was associated with lower birth weight of the infant. Preterm birth was associated with autoantibodies against chromatin. IFN-alpha protein levels associated positively with autoantibodies against chromatin, Smith/RNP (SmRNP) and RNP, but negatively with aPL antibodies.Conclusion Elevated IFN-alpha protein in plasma of women with SLE is a potential risk factor for lower birth weight of their infants. The association between IFN-alpha and lower birth weight warrants further investigation regarding the pathophysiological role of IFN-alpha during SLE pregnancy. Graphical Abstract
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| 26. |
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| 27. |
- Svanberg, Andreas
(författare)
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Full-Scale Modelling and Simulation of Bucket Filling and Wear for Mining Rope Shovels
- 2021
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Handling of granular material occurs all over the world for different reasons and under different conditions. In the mining industry, granular material handling is present in almost all processes. The machinery that deals with the granular material is typically subjected to significant wear. The loading process is a very crucial task in any mine. During the loading process, fragmented material is loaded with large rope- or hydraulic shovels. In open-pit mines, machines capable of loading more than 100 tonnes of fragmented rocks per bucket are often used. Maximizing the availability and increasing the productivity of these enormous machines are two challenges that are crucial in order to maintain the production.The work in this thesis is divided up into two parts, where the first part is to develop a numerical model to simulate granular material handling for full-scale applications, and the second part is to develop a wear model suitable for the prediction of abrasive sliding and impact wear for full-scale industrial use. A numerical model utilizing the discrete element method (DEM) in combination with rigid-finite element (FE) is used to obtain a realistic granular material model of copper ore. A multi rigid body dynamics model is utilized to model a realistic dynamic model of a rope shovel. Novel full-scale in-situ experiments are used for calibration and validation of the granular material model. A wear model, with the basis of the traditional Finnie's wear model is developed. The model enables the calculation of wear for different impact angles varying between sliding to vertical impacts. Calibration of the wear model is performed by measuring the wear on steel plates belonging to a vibratory feeder. A sensitivity analysis is performed to investigate how the particle size distribution (PSD) and the FE grid size influences the numerical wear. Furthermore, the model is validated by comparing predicted wear from simulations with experimentally measured wear on a rope shovel bucket.Validation of the granular material model from drone video recordings, and measurements of mass in the bucket confirms that the granular material model is able to capture the main phenomenon during the loading process. Validation of the wear simulation model agrees exceptionally well between the predicted wear when compared to the experimentally obtained wear data. In conclusion, numerical models including prediction of wear are developed and demonstrated for the loading process. Calibration and validation approaches for full-scale industrial use are also presented. The presented model can be used as a tool for industries to make better decisions regarding e.g. how to increase productivity and reduce wear.
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| 28. |
- Svanberg, Andreas, et al.
(författare)
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Full-scale simulation and validation of bucket filling for a mining rope shovel by using a combined rigid FE-DEM granular material model
- 2021
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Ingår i: Computational Particle Mechanics. - : Springer. - 2196-4386 .- 2196-4378. ; 8, s. 825-843
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Tidskriftsartikel (refereegranskat)abstract
- Rope shovels and other heavy mining equipment used for loading fragmented rocks to extract minerals from the earth are used in almost every open pit mine. The optimization of the loading process is of enormous value due to the extremely large amount of material turn over. In this work, a full-scale numerical model of the loading process is developed. Granular material of copper ore is modeled in a combination of rigid finite elements for larger particles with complex shapes, and the discrete element method for smaller particles. A multi rigid body dynamic model, discretized with finite elements are used to model the rope shovel. Calibration of the numerical model for the granular material is performed via a new and unique experimental full-scale approach of analyzing waste rock pile angles with a height of approximately 15 m. In situ experimental data acquisition is performed during the loading process for validation of the model. After model validation, the influence of several loading variables such as bucket rake angle, velocity, and position from the pile are investigated and evaluated. When comparing the numerical model results with experimental mass measurement an excellent agreement was observed. Also, drone camera video recordings of the mass flow behavior and the numerical mass flow behavior are in agreement. Small adjustments of dig variables show a significant effect on the average dig force as well as the bucket fill factor.
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| 29. |
- Svanberg, Andreas, et al.
(författare)
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Full-Scale Simulation and Validation of Wear for a Mining Rope Shovel Bucket
- 2021
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Ingår i: Minerals. - : MDPI. - 2075-163X. ; 11:6
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Tidskriftsartikel (refereegranskat)abstract
- Failure in industrial processes is often related to wear and can cause significant problems. It is estimated that approximately 1–4% of the gross national product for an industrialized nation is related to abrasive wear. This work aims to numerically predict development of wear for full-scale mining applications in harsh sub-arctic conditions. The purpose is to increase the understanding of wear development in industrial processes and optimize service life and minimize costs related to wear. In the present paper, a granular material model consisting of the discrete element method (DEM) and rigid finite element particles is utilized to study wear in full-scale mining applications where granular materials and steel structures are present. A wear model with the basis in Finnie’s wear model is developed to calculate wear from combined abrasive sliding and impact wear. Novel in situ full-scale experiments are presented for calibration of the wear model. A simulation model of the rope shovel loading process is set up where the bucket filling process is simulated several times, and the wear is calculated with the calibrated wear model. From the full-scale validation, it is shown that the simulated wear is in excellent agreement when compared to the experiments, both regarding wear locations and magnitudes. After validation, the model is utilized to study if wear can be minimized by making small changes to the bucket. One major conclusion from the work is that the presented wear simulator is a suitable tool that can be used for product development and optimization of the loading process.
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| 30. |
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