| 1. |
- Ericsson, Olle, et al.
(author)
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Clinical validation of a novel automated cell-free DNA screening assay for trisomies 21, 13, and 18 in maternal plasma.
- 2019
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In: Prenatal diagnosis. - : Wiley. - 1097-0223 .- 0197-3851. ; 39:11, s. 1011-1015
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Journal article (peer-reviewed)abstract
- To evaluate clinical performance of a new automated cell-free (cf)DNA assay in maternal plasma screening for trisomies 21, 18, and 13, and to determine fetal sex.Maternal plasma samples from 1200 singleton pregnancies were analyzed with a new non-sequencing cfDNA method, which is based on imaging and counting specific chromosome targets. Reference outcomes were determined by either cytogenetic testing, of amniotic fluid or chorionic villi, or clinical examination of neonates.The samples examined included 158 fetal aneuploidies. Sensitivity was 100% (112/112) for trisomy 21, 89% (32/36) for trisomy 18, and 100% (10/10) for trisomy 13. The respective specificities were 100%, 99.5%, and 99.9%. There were five first pass failures (0.4%), all in unaffected pregnancies. Sex classification was performed on 979 of the samples and 99.6% (975/979) provided a concordant result.The new automated cfDNA assay has high sensitivity and specificity for trisomies 21, 18, and 13 and accurate classification of fetal sex, while maintaining a low failure rate. The study demonstrated that cfDNA testing can be simplified and automated to reduce cost and thereby enabling wider population-based screening.
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| 2. |
- Petersson, Malin, et al.
(author)
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Patient-reported symptom severity in a nationwide myasthenia gravis cohort : cross-sectional analysis of the Swedish GEMG study
- 2021
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In: Neurology. - : Lippincott Williams & Wilkins. - 0028-3878 .- 1526-632X. ; 97:14, s. e1382-e1391
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Journal article (peer-reviewed)abstract
- Background and Objectives: To describe myasthenia gravis activities of daily living (MG-ADL) in relation to clinical characteristics in a large Swedish nationwide cohort.Methods: In a cross-sectional prevalence cohort study, the Genes and Environment in Myasthenia Gravis study, performed from November 2018 through August 2019, patients with myasthenia gravis (MG) were invited to submit an extensive 106-item life environment questionnaire, including the MG-ADL score. Patients were classified into early-onset MG (EOMG, <50 years), late-onset MG (LOMG, >= 50 years), or thymoma-associated MG (TAMG). Comparisons of disease-specific characteristics were made between subgroups, sexes, and different MG-ADL scores.Results: A total of 1,077 patients were included, yielding a 74% response rate: 505 (47%) were classified as EOMG, 520 (48%) LOMG, and 45 (4%) TAMG. Mean age at inclusion was 64.3 years (SD 15.7) and mean disease duration was 14.6 years (SD 14.0). Complete MG-ADL scores (n = 1,035) ranged from 0p to 18p, where 26% reported a score of 0p. Higher MG-ADL scores were associated with female sex, obesity, and diagnostic delay (odds ratio [OR] 1.62, 1.72, and 1.69; p(adj) = 0.017, 0.013, and 0.008) and inversely correlated with high educational attainment (OR 0.59; p(adj) = 0.02), but not with age at inclusion, disease subtype, or disease duration. Almost half of the population (47%) reported MG-ADL >= 3p, corresponding to an unsatisfactory symptom state.Discussion: In this nationwide study, comprising more than 40% of the prevalent MG population in Sweden, almost half of the patients reported current disease symptoms associated with an unsatisfactory symptom state, indicating the need for improved treatment options.
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| 3. |
- Andersson, Anton, et al.
(author)
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A Method for Synthesizing Iron Silicate Slags to Evaluate Their Performance as Supplementary Cementitious Materials
- 2023
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In: Applied Sciences. - : Mdpi. - 2076-3417. ; 13:14
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Journal article (peer-reviewed)abstract
- Utilizing iron silicate copper slag as supplementary cementitious material (SCM) is a means to improve resource efficiency and lower the carbon dioxide emissions from cement production. Despite multiple studies on the performance of these slags in SCM applications, the variations in cooling procedure, grinding, and methods for evaluating reactivity limit the ability to assess the influence of chemical composition on reactivity from the literature data. In this study, a methodology was developed to synthesize iron silicate slags, which were then evaluated for their inherent reactivity using the R-3 calorimeter-based experiments. The results demonstrated that laboratory-scale granulation produced the same reactivity as industrially granulated slag. Furthermore, a synthesized triplicate sample showed high repeatability. Based on these two aspects, this method can be used to systematically study the influence of chemical composition on the inherent reactivity of iron silicate slags while producing results that are directly translatable to industrial slags.
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| 4. |
- Andersson, Anton, et al.
(author)
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Ground granulated iron silicate slag as supplementary cementitious material: Effect of prolonged grinding and granulation temperature
- 2023
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In: Cleaner Materials. - : Elsevier. - 2772-3976. ; 10
-
Journal article (peer-reviewed)abstract
- The metallurgical and cement industries contribute significantly to anthropogenic carbon dioxide emissions. Utilizing oxidic by-products from the metallurgical industry as supplementary cementitious materials (SCMs) can improve resource efficiency and reduce emissions from cement production. Iron silicate copper slags have been studied as SCMs, but mainly in systems where Portland cement is used as an activator. There is limited research on the inherent reactivity of the slag under changing processing conditions. The present study offers insight into the effect of granulation temperature and grinding on the inherent reactivity of an industrially produced iron silicate copper slag. The results showed that granulation temperature had an insignificant effect on reactivity, while grinding generated substantial improvements. The latter effect was concluded to stem from the increased specific surface area, increased number of sites for nucleation and growth of hydrates, and changes in the inherent reactivity owing to structural changes induced by the grinding.
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| 5. |
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| 6. |
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| 7. |
- Borg, Sixten, et al.
(author)
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Patient-Reported Outcome Measures and Risk Factors in a Quality Registry: A Basis for More Patient-Centered Diabetes Care in Sweden
- 2014
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In: International Journal of Environmental Research and Public Health. - : MDPI AG. - 1660-4601. ; 11:12, s. 12223-12246
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Journal article (peer-reviewed)abstract
- Diabetes is one of the chronic diseases that constitute the greatest disease burden in the world. The Swedish National Diabetes Register is an essential part of the diabetes care system. Currently it mainly records clinical outcomes, but here we describe how it has started to collect patient-reported outcome measures, complementing the standard registry data on clinical outcomes as a basis for evaluating diabetes care. Our aims were to develop a questionnaire to measure patient abilities and judgments of their experience of diabetes care, to describe a Swedish diabetes patient sample in terms of their abilities, judgments, and risk factors, and to characterize groups of patients with a need for improvement. Patient abilities and judgments were estimated using item response theory. Analyzing them together with standard risk factors for diabetes comorbidities showed that the different types of data describe different aspects of a patient's situation. These aspects occasionally overlap, but not in any particularly useful way. They both provide important information to decision makers, and neither is necessarily more relevant than the other. Both should therefore be considered, to achieve a more complete evaluation of diabetes care and to promote person-centered care.
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| 8. |
- de Miranda, Noel F. C. C., et al.
(author)
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DNA repair genes are selectively mutated in diffuse large B cell lymphomas
- 2013
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In: Journal of Experimental Medicine. - : Rockefeller University Press. - 0022-1007 .- 1540-9538. ; 210:9, s. 1729-1742
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Journal article (peer-reviewed)abstract
- DNA repair mechanisms are fundamental for B cell development, which relies on the somatic diversification of the immunoglobulin genes by V(D)J recombination, somatic hypermutation, and class switch recombination. Their failure is postulated to promote genomic instability and malignant transformation in B cells. By performing targeted sequencing of 73 key DNA repair genes in 29 B cell lymphoma samples, somatic and germline mutations were identified in various DNA repair pathways, mainly in diffuse large B cell lymphomas (DLBCLs). Mutations in mismatch repair genes (EXO1, MSH2, and MSH6) were associated with microsatellite instability, increased number of somatic insertions/deletions, and altered mutation signatures in tumors. Somatic mutations in nonhomologous end-joining (NHEJ) genes (DCLRE1C/ARTEMIS, PRKDC/DNA-PKcs, XRCC5/KU80, and XRCC6/KU70) were identified in four DLBCL tumors and cytogenetic analyses revealed that translocations involving the immunoglobulin-heavy chain locus occurred exclusively in NHEJ-mutated samples. The novel mutation targets, CHEK2 and PARP1, were further screened in expanded DLBCL cohorts, and somatic as well as novel and rare germline mutations were identified in 8 and 5% of analyzed tumors, respectively. By correlating defects in a subset of DNA damage response and repair genes with genomic instability events in tumors, we propose that these genes play a role in DLBCL lymphomagenesis.
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| 9. |
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| 10. |
- Farrokhnia, Nasim, et al.
(author)
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Differential early mitogen-activated protein kinase activation in hyperglycemic ischemic brain injury in the rat
- 2005
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In: European Journal of Clinical Investigation. - : Wiley. - 0014-2972 .- 1365-2362. ; 35:7, s. 457-463
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Journal article (peer-reviewed)abstract
- BACKGROUND: Hyperglycemia aggravates brain injury induced by focal ischemia-reperfusion. The mitogen-activated protein kinase (MAPK) members extracellular-signal regulated kinase (Erk) and c-Jun N-terminal kinase (JNK) have been proposed as mediators of ischemic brain injury, and Erk is strongly activated by combined hyperglycemia and transient global ischemia. It is unclear whether similar MAPK activation appears in focal brain ischemia with concomitant hyperglycemia. DESIGN: Hyperglycemia was induced in rats by an intraperitoneal bolus of glucose (2 g kg(-1)). The rats were then subjected to 90 min of transient middle cerebral artery occlusion (MCAO). Erk and JNK activation were investigated with immunofluorescence and Western blot along with infarct size measurement based on tetrazolium staining and neurological score. RESULTS: The hyperglycemic rats showed increased tissue damage and impaired neurological performance after 1 day compared with controls. The hyperglycemia was generally moderate (< 15 mM). Erk activation was increased after 30 min of reperfusion in the ischemic cortex of the hyperglycemic rats, while JNK activation was present on the contralateral side. Phospho-Erk immunofluorescence revealed marked neuronal activation of Erk in the ischemic cortex of hyperglycemic rats compared with controls. CONCLUSION: Besides confirming the detrimental effects of hyperglycemia on focal ischemia-reperfusion, this study shows that hyperglycemia strongly activates the pathogenic mediator Erk in the ischemic brain in the early phase of reperfusion. JNK activation at this stage is present in the nonischemic hemisphere. The functional relevance of these findings needs further investigation.
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| 11. |
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| 12. |
- Farrokhnia, Nasim, et al.
(author)
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Experimental treatment for focal hyperglycemic ischemic brain injury in the rat
- 2005
-
In: Experimental Brain Research. - : Springer Science and Business Media LLC. - 0014-4819 .- 1432-1106. ; 167:2, s. 310-314
-
Journal article (peer-reviewed)abstract
- Hyperglycemia aggravates ischemic brain injury, possibly due to the activation of signaling pathways involving reactive oxygen species, Src and mitogen-activated protein kinases. The aim of this study was to investigate the effects of the spin trap agent alpha-phenyl-N-tert-butyl nitrone (PBN), the Src family kinase inhibitor PP2 and the MEK1-inhibitor U0126 on focal hyperglycemic ischemic brain injury. Temporary middle cerebral artery occlusion (90 min) was induced in four groups of rats (PBN, PP2, and U0126 vs. control). Neurological testing and tetrazolium red staining were performed after 1 day. PBN decreased the infarct volume by 70% compared with the control (P<0.05) and a tendency towards reduced infarcts was seen in the PP2 or U0126 groups. Furthermore, neurological testing was consistent with the volumetric analysis. In conclusion, PBN appears to be a potential neuroprotective agent in hyperglycemic, focal ischemic brain injury, while the efficacy of PP2 and U0126 could not be confirmed by the present data.
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| 13. |
- Henricsson, Fredrik, et al.
(author)
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Aspects on the analysis of (210)Po.
- 2011
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In: Journal of Environmental Radioactivity. - : Elsevier BV. - 1879-1700 .- 0265-931X. ; 102:5, s. 415-419
-
Journal article (peer-reviewed)abstract
- There has been little development regarding analysis of polonium (Po) in environmental samples since the 1960ies. This is due to the straightforward spontaneous deposition of this element on silver (Ag), nickel (Ni) or copper (Cu) without any radiochemical separation. For many years, no radiochemical yield determinant was used and it was generally supposed that the yield was 100% after two depositions. Counting was often done using ZnS scintillation counter coupled to a photomultiplier tube. However, the use of the yield determinants (208)Po and (209)Po and the development of alpha spectrometry showed that the yield was lower. Furthermore, the tendency of Po to volatilize at low temperatures constrains the sample preparation techniques; dry-ashing cannot be used. But during the wet-ashing procedure, there are still some losses. The aim of this study was to evaluate the Po losses during wet-ashing by the use of a double-tracer technique. We have found that the losses were about 30% when open glass beakers were used and about 17% when the samples were digested in microwave oven. When long-necked bottles (Kjeldahl flasks) were used, a loss of about 20% was registered. It has also been observed that (210)Pb to some extent is plating out together with its daughter nuclide Po during the electrochemical deposition. This will result in a systematic error since an unknown amount of supported (210)Po will be produced from the (210)Pb decay depending on the fraction of (210)Pb being deposited on the disc and the waiting time between deposition and measurement of the sample. A further consequence of this is that in the assessment of the (210)Pb content in the sample, very often the remaining liquid is stored after deposition for build-up of (210)Po. Since some (210)Pb is lost on the disc, the result for (210)Pb will be too low. Both these systematic errors give rise to a too high (210)Po/(210)Pb ratio. The fraction of (210)Pb which is plating out has been assessed in this study for different matrices and is about 50-90%. During the measurement by solid state Si-detectors, some Po is evaporated in the vacuum conditions contaminating the detectors. Experiments have here been done by heating the discs after deposition which indicate that less Po is evaporated from Ag than from Ni. The losses from Ag are less than that from the other metals probably due to a deeper penetration into the surface of Po. We conclude that in most aspects, Ag is better to use than the other plating metals.
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| 14. |
- Henriksson, Manne, 1987-, et al.
(author)
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Implementation of an Optimal Look-Ahead Controller in a Heavy-Duty Distribution Vehicle
- 2019
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In: Proceedings 2019 IEEE Intelligent Vehicles Symposium (IV). ; , s. 2202-2207
-
Conference paper (peer-reviewed)abstract
- Controlling the longitudinal movement of heavy-duty vehicles based on optimal control can be a cost-efficient way of reducing their fuel consumption. Such controllers today mainly exist for vehicles in haulage applications, in which the velocity is allowed to deviate from a constant set-speed. For distribution vehicles, which is the focus of this paper, the desired and required velocity has large variations, which makes the situation more complex. This paper describes the implementation of an optimal controller in a real heavy-duty distribution vehicle. The optimal control problem is solved offline as a Mixed Integer Quadratic Program, which yields reference trajectories that are tracked online in the vehicle. Some important steps in the procedure of the implementation are, except for designing the controller: developing a positioning system for the test track where the experiments are performed, estimating the parameters of the resistive forces, and setting the velocity constraints. Simulations show a potential of 10% reduction in fuel consumption without increasing the trip time. Experiments are then performed in a Scania truck, with the optimal solution as reference for the existing cruise control functions in the vehicle. It is concluded that in order to verify the fuel savings experimentally, the low-level controllers in the vehicle must be modified such that the tracking error is decreased.
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| 15. |
- Henriksson, Manne, 1987-, et al.
(author)
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Optimal Freewheeling Control of a Heavy-Duty Vehicle Using Mixed Integer Quadratic Programming
- 2020
-
In: IFAC PAPERSONLINE. - : Elsevier BV. - 2405-8963. ; , s. 13809-13815
-
Conference paper (peer-reviewed)abstract
- Improving the powertrain control of heavy-duty vehicles can be an efficient way to reduce the fuel consumption and thereby reduce both the operating cost and the environmental impact. One way of doing so is by using information about the upcoming driving conditions, known as look-ahead information, in order to coast in gear or to use freewheeling. Controllers using such techniques today mainly exist for vehicles in highway driving. This paper therefore targets how such control can be applied to vehicles with more variations in their velocity. The driving mission of such a vehicle is here formulated as an optimal control problem. The control variables are the tractive force, the braking force, and a Boolean variable representing closed or open powertrain. The problem is solved by a model predictive controller, which at each iteration solves a mixed integer quadratic program. The fuel consumption is compared for four different control policies: a benchmark following the reference of the driving cycle, look-ahead control without freewheeling, freewheeling with the engine idling, and freewheeling with the engine turned off. Simulations on a driving cycle with a varying velocity profile show the potential of saving 11 %, 19 %, and 23% respectively for the control policies compared with the benchmark, in all cases without increasing the trip time. Copyright
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| 16. |
- Hultdin, Magnus, et al.
(author)
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Association between telomere length and V-H gene mutation status in chronic lymphocytic leukaemia : clinical and biological implications
- 2003
-
In: British Journal of Cancer. - London : Nature Publishing Group. - 0007-0920 .- 1532-1827. ; 88:4, s. 593-598
-
Journal article (peer-reviewed)abstract
- The immunoglobulin V-H gene mutation status can divide B-cell chronic lymphocytic leukaemia (CLL) into two entities with a different clinical course. Cases with unmutated V-H genes, considered to evolve from pregerminal centre (GC) cells, have a worse outcome compared to cases showing mutated VH genes, that is, post-GC derived. Also, telomere length has been reported to be of prognostic significance in CLL. Interestingly, telomerase becomes activated during the GC reaction and an elongation of the telomeres occurs in GC B cells. We performed telomere length and VH gene analysis in a series of 61 CLL cases, in order to investigate if the unique telomere lengthening shown in GC B cells could reflect the telomere status in the two subsets of mutated and unmutated CLL. A novel association was found between VH gene mutation status and telomere length, since significantly shorter telomeres were demonstrated in the unmutated group compared to the mutated group (mean length 4.3 vs 63 kbp). Shorter telomeres also constituted a subgroup with a worse prognosis than cases with longer telomeres (median survival 59 vs 159 months), Furthermore, the I-g gene sequence data revealed that samples with high mutations frequency (> 6%) had long telomeres (similar to 8 kbp). Thus, both the telomere and VH gene mutation status in CLL appear linked, which may reflect the proliferative history of the clonal cells with regard to the GC reaction. (C) 2003 Cancer Research UK.
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| 17. |
- Hultdin, Magnus, et al.
(author)
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Replication timing of human telomeric DNA and other repetitive sequences analyzed by fluorescence in situ hybridization and flow cytometry
- 2001
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In: Experimental Cell Research. - : Elsevier. - 0014-4827. ; 271, s. 223-229
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Journal article (peer-reviewed)abstract
- The replication timing of telomeres seems to differ between species. Yeast telomeres are late replicating, whereas limited data from very few human cell lines have indicated telomere replication throughout S phase. In the present study a series of permanent cell lines and patient samples was investigated using a flow cytometric approach for telomere length determination based on in situ hybridization using peptide nucleic acid probes and DNA staining. This method permits selective analysis of cells in specific phases of the cell cycle without perturbation of the cell cycle machinery. The timing of replication of telomeric C(3)TA(2) and T(2)AG(3) repeats was found to differ between individual samples and could precede or be concomitant with the replication of bulk DNA. Replication of the T(2)AG(3) strand seemed to occur somewhat later than that of the C(3)TA(2) strand in some samples. (GTG)(n) and other repetitive sequences generally showed a replication pattern similar to that of the bulk of DNA with slightly individual differences, whereas centromeric DNA repeats consistently replicated within a short time frame in late S phase. The apparent variability in replication timing seen for telomeric DNA might suggest individual differences in firing of replication origins.
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| 18. |
- Hultdin, Magnus, et al.
(author)
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Telomere analysis by fluorescence in situ hybridization and flow cytometry
- 1998
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In: Nucleic Acids Research. - Oxford : Oxford University Press. - 0305-1048 .- 1362-4962. ; 26:16, s. 3651-3656
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Journal article (peer-reviewed)abstract
- Determination of telomere length is traditionally performed by Southern blotting and densitometry, giving a mean telomere restriction fragment (TRF) value for the total cell population studied. Fluorescence in situ hybridization (FISH) of telomere repeats has been used to calculate telomere length, a method called quantitative (Q)-FISH, We here present a quantitative flow cytometric approach, Q-FISHFCM, for evaluation of telomere length distribution in individual cells based on in situ hybridization using a fluorescein-labeled peptide nucleic acid (PNA) (CCCTAA)(3) probe and DMA staining with propidium iodide, A simple and rapid protocol with results within 30 h was developed giving high reproducibility, One important feature of the protocol was the use of an internal cell line control, giving an automatic compensation for potential differences in the hybridization steps. This protocol was tested successfully on cell lines and clinical samples from bone marrow, blood, lymph nodes and tonsils. A significant correlation was found between Southern blotting and Q-FISHFCM telomere length values (P = 0.002), The mean sub-telomeric DNA length of the tested cell lines and clinical samples was estimated to be 3.2 kbp, With the Q-FISHFCM method the fluorescence signal could be determined in different cell cycle phases, indicating that in human cells the vast majority of telomeric DNA is replicated early in S phase.
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| 19. |
- Johannesson, T, et al.
(author)
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Reliability of Protection Systems - Operational Experiences 1976-2002
- 2004
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In: 8th International Conference on Development in Power System Protection. - 0863413854 ; 1, s. 303-306
-
Conference paper (peer-reviewed)abstract
- This paper presents the results of an extensive survey on incorrect protection operations performed in Sweden on an electric power system owned by Sydkraft. The survey is based on disturbance reports and special investigation reports for the period 1976-2002. The results indicate the occurrence of the major types and causes of incorrect protection operations that have been revealed at disturbances in the electric power system under study.
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| 20. |
- Johansson, Kari, et al.
(author)
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Outcomes of pregnancy after bariatric surgery
- 2015
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In: New England Journal of Medicine. - 0028-4793 .- 1533-4406. ; 372:9, s. 814-824
-
Journal article (peer-reviewed)abstract
- BACKGROUND: Maternal obesity is associated with increased risks of gestational diabetes, large-for-gestational-age infants, preterm birth, congenital malformations, and stillbirth. The risks of these outcomes among women who have undergone bariatric surgery are unclear.METHODS: We identified 627,693 singleton pregnancies in the Swedish Medical Birth Register from 2006 through 2011, of which 670 occurred in women who had previously undergone bariatric surgery and for whom presurgery weight was documented. For each pregnancy after bariatric surgery, up to five control pregnancies were matched for the mother's presurgery body-mass index (BMI; we used early-pregnancy BMI in the controls), age, parity, smoking history, educational level, and delivery year. We assessed the risks of gestational diabetes, large-for-gestational-age and small-for-gestational-age infants, preterm birth, stillbirth, neonatal death, and major congenital malformations.RESULTS: Pregnancies after bariatric surgery, as compared with matched control pregnancies, were associated with lower risks of gestational diabetes (1.9% vs. 6.8%; odds ratio, 0.25; 95% confidence interval [CI], 0.13 to 0.47; P< 0.001) and large-for-gestational-age infants (8.6% vs. 22.4%; odds ratio, 0.33; 95% CI, 0.24 to 0.44; P< 0.001). In contrast, they were associated with a higher risk of small-for-gestational-age infants (15.6% vs. 7.6%; odds ratio, 2.20; 95% CI, 1.64 to 2.95; P< 0.001) and shorter gestation (273.0 vs. 277.5 days; mean difference -4.5 days; 95% CI, -2.9 to -6.0; P< 0.001), although the risk of preterm birth was not significantly different (10.0% vs. 7.5%; odds ratio, 1.28; 95% CI, 0.92 to 1.78; P = 0.15). The risk of stillbirth or neonatal death was 1.7% versus 0.7% (odds ratio, 2.39; 95% CI, 0.98 to 5.85; P = 0.06). There was no significant between-group difference in the frequency of congenital malformations.CONCLUSIONS: Bariatric surgery was associated with reduced risks of gestational diabetes and excessive fetal growth, shorter gestation, an increased risk of small-for-gestational-age infants, and possibly increased mortality.
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| 21. |
- Jonasson, Mats, et al.
(author)
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Design and evaluation of an active electromechanical wheel suspension system
- 2008
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In: Mechatronics (Oxford). - : Elsevier BV. - 0957-4158 .- 1873-4006. ; 18:4, s. 218-230
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Journal article (peer-reviewed)abstract
- This paper presents an electromechanical wheel suspension, where the upper arm of the suspension has been provided with an electric levelling and a damper actuator, both are allowed to work in a fully active mode. A control structure for the proposed suspension is described. The complex design task involving the control of the electric damper and its machine parameters is tackled by genetic optimisation. During this process, these parameters are optimised to keep the power dissipation of the electric damper as low as possible, while maintaining acceptable comfort and road-holding capabilities. The results of the evaluations carried out demonstrate that the proposed suspension can easily adopt its control parameters to obtain a better compromise of performance than that offered by passive suspensions. If the vehicle is to maintain acceptable performance during severe driving conditions, the damper has to be unrealistically large. However, if the electric damper is combined with a hydraulic damper, the size of the electric damper is significantly reduced. In addition, the design of the electric damper with the suggested control structure, including how it regenerates energy, is discussed.
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| 22. |
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| 23. |
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| 24. |
- Kaznov, Viktor, et al.
(author)
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Architecture and Safety for Autonomous Heavy Vehicles: ARCHER
- 2017
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In: Automated Driving. - Cham : Springer International Publishing. - 9783319318936 - 9783319318950 ; , s. 571-581
-
Book chapter (peer-reviewed)abstract
- Machines are converging towards autonomy. The transition is driven by safety, efficiency, environmental and traditional ‘robotics automation concerns’ (dirty, dull and dangerous applications). Similar trends are seen in several domains including heavy vehicles, cars and aircraft. This transition is, however, facing multiple challenges including how to gradually evolve from current architectures to autonomous systems, limitations in legislation and safety standards, test and verification methodology and human–machine interaction.
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| 25. |
- Kepka, Cecilia, et al.
(author)
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Two-step recovery process for tryptophan tagged cutinase : Interfacing aqueous two-phase extraction and hydrophobic interaction chromatography
- 2005
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In: Journal of Chromatography A. - : Elsevier BV. - 0021-9673 .- 1873-3778. ; 1075:02-jan, s. 33-41
-
Journal article (peer-reviewed)abstract
- In this work, the interfacing of a poly(ethylene glycol) (PEG)-phosphate aqueous two-phase system with hydrophobic interaction chromatography (HIC) for primary recovery of an intracellular protein was evaluated. As a model protein, a recombinant cutinase furnished with a tryptophan-proline (WP) peptide tag was used and produced intracellularly in Escherichia coli (E. coli). E. coli cell homogenate was partitioned in a two-phase system and the top phase yield, concentration and purity of the tagged ZZ-cutinase-(WP)(4) was evaluated as function of polymer sizes, system pH and phase volume ratio. The partition behaviour of cell debris, total protein and endotoxin was also monitored. In the HIC part, the chromatographic yield and purity was investigated with respect to ligand hydrophobicity, dilution of loaded top phase and elution conditions. Based on the results, a recovery process was demonstrated where a PEG 1500-K-Na phosphate salt aqueous two-phase system was interfaced with a HIC column. The interfacing was facilitated by the Trp-tagged peptide. The tagged ZZ-cutinase-(WP)4 was obtained in a PEG-free phase and purified to > 95% purity according to silver stained sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) gels with a total yield of 83% during the two-step recovery process. © 2005 Elsevier B.V. All rights reserved.
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| 26. |
- Mark-Herbert, Cecilia, et al.
(author)
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Urban Planners’ Perspectives on Public Private Partnership for Wooden Multistorey Construction
- 2023
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In: Journal of Forest Economics. - : Now Publishers. - 1104-6899 .- 1618-1530. ; 38, s. 7-35
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Journal article (peer-reviewed)abstract
- Increased awareness of sustainable development in the construction industry and current housing shortages have contributed to market opportunities for wooden multi-storey construction (WMC) in the Nordic countries. However, the market development has been slow despite access to forest products and a political ambition to transform to a low carbon society. The aim of this study is to explain enabling factors for municipalities in Sweden to create institutional conditions that stimulate local market development of WMC. A comparative case study of municipal efforts to establish WMC norms has been conducted pointing to the importance of relationships, in so-called public private partnerships (PPP). These partnerships serve as long-lasting relations in which development processes can manage challenges relating to, for example, lack of professional experience in WMC and dated material understandings of wood as a construction material. In the Sustainable Development Goals, PPP represent enabling conditions for sustainable system transformations.
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| 27. |
- Nordfjäll, Katarina, et al.
(author)
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Large-scale parent-child comparison confirms a strong paternal influence on telomere length
- 2010
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In: European Journal of Human Genetics. - Basel : Karger. - 1018-4813 .- 1476-5438. ; 18:3, s. 385-389
-
Journal article (peer-reviewed)abstract
- Telomere length is documented to have a hereditary component, and both paternal and X-linked inheritance have been proposed. We investigated blood cell telomere length in 962 individuals with an age range between 0 and 102 years. Telomere length correlations were analyzed between parent-child pairs in different age groups and between grandparent-grandchild pairs. A highly significant correlation between the father's and the child's telomere length was observed (r=0.454, P<0.001), independent of the sex of the offspring (father-son: r=0.465, P<0.001; father-daughter: r=0.484, P<0.001). For mothers, the correlations were weaker (mother-child: r=0.148, P=0.098; mother-son: r=0.080, P=0.561; mother-daughter: r=0.297, P=0.013). A positive telomere length correlation was also observed for grandparent-grandchild pairs (r=0.272, P=0.013). Our findings indicate that fathers contribute significantly stronger to the telomere length of the offspring compared with mothers (P=0.012), but we cannot exclude a maternal influence on the daughter's telomeres. Interestingly, the father-child correlations diminished with increasing age (P=0.022), suggesting that nonheritable factors have an impact on telomere length dynamics during life.
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| 28. |
- Nordfjäll, Katarina, et al.
(author)
-
The individual blood cell telomere attrition rate is telomere length dependent.
- 2009
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In: PLoS genetics. - : Public Library of Science. - 1553-7404. ; 5:2, s. e1000375-
-
Journal article (peer-reviewed)abstract
- Age-associated telomere shortening is a well documented feature of peripheral blood cells in human population studies, but it is not known to what extent these data can be transferred to the individual level. Telomere length (TL) in two blood samples taken at approximately 10 years interval from 959 individuals was investigated using real-time PCR. TL was also measured in 13 families from a multigenerational cohort. As expected, we found an age-related decline in TL over time (r = -0.164, P<0.001, n = 959). However, approximately one-third of the individuals exhibited a stable or increased TL over a decade. The individual telomere attrition rate was inversely correlated with initial TL at a highly significant level (r = -0.752, P<0.001), indicating that the attrition rate was most pronounced in individuals with long telomeres at baseline. In accordance, the age-associated telomere attrition rate was more prominent in families with members displaying longer telomeres at a young age (r = -0.691, P<0.001). Abnormal blood TL has been reported at diagnosis of various malignancies, but in the present study there was no association between individual telomere attrition rate or prediagnostic TL and later tumor development. The collected data strongly suggest a TL maintenance mechanism acting in vivo, providing protection of short telomeres as previously demonstrated in vitro. Our findings might challenge the hypothesis that individual TL can predict possible life span or later tumor development.
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| 29. |
- Norrback, Karl Fredrik, et al.
(author)
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Telomerase activation in normal B lymphocytes and non-Hodgkin's lymphomas
- 1996
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In: Blood. - 0006-4971 .- 1528-0020. ; 88:1, s. 222-229
-
Journal article (peer-reviewed)abstract
- Activation of telomerase seems to be a prerequisite for immortalization and is found in permanent cell lines and most malignant tumors. Normal somatic cells are generally telomerase negative, except for bone marrow stem cells. Weak activity is also present in peripheral blood cells. In the present study strong telomerase activity was demonstrated in vivo in normal mature cells of the immune system, as well as in malignant lymphomas. Benign lymph nodes had lower telomerase activity than benign tonsils, which exhibited intermediate to high activity comparable with findings in malignant lymphomas. In benign tonsils the activity seemed to be restricted to germinal center B cells. In benign lymphoid tissues telomerase activity correlated with B-cell numbers and cell proliferation, but this was not observed in the lymphoma group. High-grade lymphomas exhibited higher levels of telomerase compared with low-grade cases. The data showed that in vivo activation of telomerase is a characteristic feature of germinal center B cells. Different signals for activation of telomerase are likely to exist, one of them being immune stimulation. The data suggest that telomerase activity in malignant lymphomas can be explained by an "induction and retention" model, ie, transformation occurs in a normal, mature B cell with reactivated telomerase, which is retained in the neoplastic clone.
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| 30. |
- Norrback, Karl-Fredrik, et al.
(author)
-
Telomerase activity in Hodgkin's disease
- 1998
-
In: Blood. - 0006-4971 .- 1528-0020. ; 92:2, s. 567-573
-
Journal article (peer-reviewed)abstract
- Telomere maintenance executed by the action of telomerase seems to be a prerequisite for immortalization. Telomerase is found in most cell lines and malignant tumors. A telomerase-independent mechanism for telomere maintenance in Hodgkin's disease has been proposed in the absence of detectable telomerase activity. In this study, telomerase activity was detected in 31 of 77 Hodgkin's disease samples and a strong correlation between eosinophilia and absence of detectable telomerase activity was found. Purified eosinophils and specifically eosinophil-derived neurotoxin and eosinophilic cationic protein, both ribonucleases, were found to degrade telomerase. Purified neutrophils also exhibited weak telomerase degradative activity. Reanalysis of previously telomerase-negative Hodgkin's disease samples with eosinophilia using ribonuclease inhibitors resulted in the detection of telomerase activity. Ribonuclease-containing cells in vivo thus have a considerable impact on the detectability of telomerase. In Hodgkin's disease samples without eosinophilia, 24 of 27 exhibited telomerase activity at decreased levels compared with non-Hodgkin's lymphomas and at increased levels compared with reactive nodes indicative of a telomerase positive tumor component in Hodgkin's disease. Telomerase positivity of the Hodgkin's and Reed-Sternberg cells in vivo was also supported by high levels of telomerase expression in Hodgkin's disease cell lines. Based on our data, Hodgkin's lymphomas are potential targets for antitelomerase therapy.
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| 31. |
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| 32. |
- Norrback, Karl-Fredrik, et al.
(author)
-
Telomerase regulation and telomere dynamics in germinal centers
- 2001
-
In: European Journal of Haematology. - : Blackwell Munksgaard. - 0902-4441 .- 1600-0609. ; 67:5-6, s. 309-317
-
Journal article (peer-reviewed)abstract
- Telomere length maintenance, usually executed by telomerase, is a prerequisite for an extended or infinite division potential. Nevertheless most telomerase positive normal cells exhibit telomere shortening. This study details the telomerase expression and telomere dynamics in purified tonsil B cell subsets during the germinal center (GC) reaction. Significant telomere lengthening was observed as naive B cells matured to centroblasts and when centroblasts matured further to centrocytes, resulting in an increase in telomere length of about 4 kbp determined by Southern blotting. Immunopurified cell populations were also studied by fluorescence in situ hybridization and flow cytometry (flow-FISH) confirming that the GC B cells exhibited lengthened telomeres. These data were further verified in unpurified tonsil cells by combining flow-FISH and immunophenotyping using selected surface markers. Centroblasts expressed high levels of telomerase activity, which was increased in centrocytes, whereas resting naive, activated naive and memory B cells were telomerase activity negative. Expression levels of the catalytic subunit (hTERT) RNA paralleled the telomerase activity levels. The unique telomere elongation in GC B cells permits extensive proliferation during the GC reaction and provides the memory cells with a substantial increase in division potential. Understanding the telomere biology of GC cells is important in defining requirements for telomere elongation in vivo, with implications for the normal immune system as well as for lymphomas, and could provide insights into how the division potential of cells can be manipulated in vitro.
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| 33. |
- Norrback, Karl-Fredrik, et al.
(author)
-
Telomeres and telomerase in normal and malignant haematopoietic cells
- 1997
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In: European Journal of Cancer. - : Elsevier. - 0959-8049 .- 1879-0852. ; 33:5, s. 774-780
-
Journal article (peer-reviewed)abstract
- The normal haematopoietic system harbours telomerase-competent cells with a capacity to upregulate the activity to notable levels in a telomere length-independent manner. Strong telomerase activity is found in progenitor stem cells and activated lymphocytes in vitro as well as in vivo, indicating that cells with high growth requirements can readily upregulate telomerase. Despite detection of telomerase activity, a gradual telomere erosion occurs in stem cells and lymphocytes, with significantly shortened telomeres at higher ages, a phenomenon that might be of importance for developing immunosenescence and exhausted haematopoiesis. In malignant haematopoietic disorders telomerase activity is a general finding with large differences in activity levels. The strongest telomerase expression has been shown in acute leukaemias and non-Hodgkin's lymphomas, especially high grade cases. There are indications that the level of activity might parallel tumour progression and be of prognostic relevance, but studies of larger patient materials are needed. An association between the cell cycle and telomerase activity exists, especially for normal haematopoietic cells, and induction of a differentiation programme in immortalised cell lines downregulates telomerase activity. The expression of telomerase activity seems to be regulated at different levels, since for immature bone marrow cells the level of activity seemed to parallel better the phenotype than the proliferation state. The frequent expression of telomerase in leukaemias and lymphomas makes these disorders interesting targets for future anti-telomerase therapy.
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| 34. |
- Orho-Melander, Marju, et al.
(author)
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Common Missense Variant in the Glucokinase Regulatory Protein Gene Is Associated With Increased Plasma Triglyceride and C-Reactive Protein but Lower Fasting Glucose Concentrations
- 2008
-
In: Diabetes. - : American Diabetes Association. - 1939-327X .- 0012-1797. ; 57:11, s. 3112-3121
-
Journal article (peer-reviewed)abstract
- OBJECTIVE-Using the genome-wide association approach, we recently identified the glucokinase regulatory protein gene (GCKR, rs780094) region as a novel quantitative trait locus for plasma triglyceride concentration in Europeans. Here, we sought to study the association of GCKR variants with metabolic phenotypes, including measures of glucose homeostasis, to evaluate the GCYR locus in samples of non-European ancestry and to fine-map across the associated genomic interval. RESEARCH DESIGN AND METHODS-We performed association studies in 12 independent cohorts comprising >45,000 individuals representing several ancestral groups (whites from Northern and Southern Europe, whites from the U.S., African Americans from the U.S., Hispanics of Caribbean origin, and Chinese, Malays, and Asian Indians from Singapore). We conducted genetic fine-mapping across the similar to 417-kb region of linkage disequilibrium. spanning GCKR and 16 other genes on chromosome 2p23 by imputing untyped HapMap single nucleotide polymorphisms (SNPs) and genotyping 104 SNPs across the associated genomic interval. RESULTS-We provide comprehensive evidence that GCYR rs780094 is associated with opposite effects on fasting plasma triglyceride (P-meta = 3 x 10(-56)) and glucose (P-meta = 1 x 10(-13)) concentrations. In addition, we confirmed recent reports that the same SNP is associated with C-reactive protein (CRP) level (P = 5 x 10(-5)). Both fine-mapping approaches revealed a common missense GCKR variant (rs1260326, Pro446Leu, 34% frequency, r(2) = 0.93 with rs780094) as the strongest association signal in the region. CONCLUSIONS-These findings point to a molecular mechanism in humans by which higher triglycerides and CRP can be coupled with lower plasma glucose concentrations and position GCKR in central pathways regulating both hepatic triglyceride and glucose metabolism. Diabetes 57:3112-3121, 2008
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| 35. |
- Palmqvist, Richard, et al.
(author)
-
hTERT gene copy number is not associated with hTERT RNA expression or telomerase activity in colorectal cancer
- 2005
-
In: International Journal of Cancer. - Geneve : International union against cancer. - 0020-7136 .- 1097-0215. ; 116:3, s. 395-400
-
Journal article (peer-reviewed)abstract
- In a majority of malignant human tumors telomerase activity can be detected, suggesting an immortal phenotype. Expression of the reverse transcriptase subunit, hTERT, in the human telomerase complex is required for telomerase activity. The regulation of hTERT, from gene level to a fully functional protein, is still a poorly understood process. Increased copy number of the hTERT gene has been demonstrated in a significant portion of established cell lines and tumors of different origin but its relevance for telomerase activity levels is unclear. In the present study, we examined the hTERT gene copy number using fluorescence in situ hybridization (FISH) in samples from 64 colorectal carcinomas and an increased copy number (≥ 3 hTERT gene copies/nucleus) was observed in 31 cases (48%). No statistical association existed between hTERT gene copy number and hTERT RNA expression or telomerase activity. However, a significant relationship was found between an increase in hTERT gene copy number and p53 protein accumulation (p = 0.002) and aneuploidy (p = 0.036). Only 4 tumors showed microsatellite instability, 3 of which had a normal hTERT gene copy number. The data indicated that the increased copy number of the hTERT gene in colorectal carcinoma was a result of genomic instability with no obvious consequence for telomerase activity levels.
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| 36. |
- Remes, K, et al.
(author)
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Telomere length and telomerase activity in malignant lymphomas at diagnosis and relapse
- 2000
-
In: British Journal of Cancer. - : Springer Science and Business Media LLC. - 0007-0920 .- 1532-1827. ; 82:3, s. 601-607
-
Journal article (peer-reviewed)abstract
- Telomere length maintenance, in the vast majority of cases executed by telomerase, is a prerequisite for long-term proliferation. Most malignant tumours, including lymphomas, are telomerase-positive and this activity is a potential target for future therapeutic interventions since inhibition of telomerase has been shown to result in telomere shortening and cell death in vitro. One prerequisite for the suitability of anti-telomerase drugs in treating cancer is that tumours exhibit shortened telomeres compared to telomerase-positive stem cells. A scenario is envisioned where the tumour burden is reduced using conventional therapy whereafter remaining tumour cells are treated with telomerase inhibitors. In evaluating the realism of such an approach it is essential to know the effects on telomere status by traditional therapeutic regimens. We have studied the telomere lengths in 47 diagnostic lymphomas and a significant telomere shortening was observed compared to benign lymphoid tissues. In addition, telomere length and telomerase activity were studied in consecutive samples from patients with relapsing non-Hodgkin's lymphomas. Shortened, unchanged and elongated telomere lengths were observed in the relapse samples. The telomere length alterations found in the relapsing lymphomas appeared to be independent of telomerase and rather represented clonal selection random at the telomere length level. These data indicate that anti-telomerase therapy would be suitable in only a fraction of malignant lymphomas.
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| 37. |
- Roos, Anders, et al.
(author)
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Impact of prospective residents dwelling requirements on preferences for house construction materials
- 2023
-
In: Wood Material Science & Engineering. - : Taylor & Francis Ltd. - 1748-0272 .- 1748-0280. ; 18:4, s. 1275-1284
-
Journal article (peer-reviewed)abstract
- This study investigated peoples requirements for multi-story housing attributes and preferences for apartments in wooden-structure versus steel/concrete-structure multi-story buildings. Data came from an online survey conducted in Finland and Sweden that screened for respondents who expressed a preference for living in an apartment, as compared with a low-rise dwelling. Responses were analyzed using exploratory factor and regression analyses. Swedish respondents assigned significantly higher requirements to factors related to environmental and social sustainability performance than Finnish respondents. Requirements in both countries were described across three factors: environmental and social sustainability, quality, and design. Factor scores differed between socioeconomic sub-groups, particularly regarding quality, between urban and non-urban respondents. Preferences to live in an apartment in a wooden building were positively associated with respondents requirements for environmental and social sustainability, and negatively with requirements for quality-related attributes. Opposite relationships were found in the Swedish sample for apartments in non-wooden structure houses. Design requirements had no significant association with preferences for a specific material in load-bearing structures for multi-story buildings, in either country. The findings can contribute toward enhanced marketing efforts and customized value propositions to increase the social acceptability of multi-story wooden buildings and advance climate-related goals within the housing sector.
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| 38. |
- Roos, Fredrik, et al.
(author)
-
Distribution System Component Failure Rates and Repair Times - An Overview
- 2004
-
Conference paper (peer-reviewed)abstract
- This paper presents the results of a literature search for publications containing failure rates and repair times, based on operational experience, for distribution system components that are critical to the reliability of a distribution system. Furthermore, component failure rates found are compared with the conclusions drawn from a previously conducted literature search.
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| 39. |
- Roos, Fredrik
(author)
-
Electricity Supply Reliability: Evaluation of Improvement Solutions for Existing Electricity Networks
- 2005
-
Licentiate thesis (other academic/artistic)abstract
- Regulation of the electricity network business is continuously under development in many countries. This is a reaction of an increasingly electricity dependent society, which demands electricity supplies at acceptable quality levels and at reasonable tariffs. Thus, electric network companies are facing new requirements that change the conditions for exercising network activities. Generally, incentives are given to the network companies to maintain the present level of reliability in a cost-efficient way. In Norway, however, incentives are given to the network companies to plan, operate and maintain the networks in a socio-economically optimal way, taking into account the supply-interruption cost to the customers. Therefore, in Norway, electricity network companies strive to identify and implement the most cost-efficient reliability improvement projects, i.e., the projects that yield the greatest overall reduction in supply-interruption cost to the customers for the invested money. In this thesis, implementations of reliability improvement solutions on a test system have been evaluated from a socio-economical point of view. For each of the alternative solutions implemented on the test system, the average annual supply-interruption cost to the customers supplied from the test system has been estimated. Furthermore, the maximum annual capital cost associated with the implementation of each solution has been estimated. Then, a reliability improvement solution is considered justified socioeconomically if the capital cost associated with its implementation is less than the resulting reduction in the interruption cost to the customers. The general conclusion from this thesis work is that the supply-interruption cost to the customers supplied from a test system can be reduced significantly by implementing reliability improvement solutions that are justified socioeconomically. Even if the uncertainty of the input data is taken into account, it is obvious from the results that the interruption cost to the test system customers can be reduced to at least half the initial value.
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| 40. |
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| 41. |
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| 42. |
- Roos, Fredrik, 1976-
(author)
-
On design methods for mechatronics : servo motor and gearhead
- 2005
-
Licentiate thesis (other academic/artistic)abstract
- The number of electric powered sub-systems in road-vehicles is increasing fast. This development is primarily driven by the new and improved functionality that can be implemented with electro-mechanical sub-systems, but it is also necessary for the transition to electric and hybrid-electric drive trains. An electromechanical sub-system can be implemented as a physically integrated mechatronic module: controller, power electronics, electric motor, transmission and sensors, all integrated into one component. A mechatronic module, spans, as all mechatronic systems, over several closely coupled engineering disciplines: mechanics, electronics, electro-mechanics, control theory and computer science. In order to design and optimize a mechatronic system it is therefore desirable to design the system within all domains concurrently. Optimizing each domain or component separately will not result in the optimal system design. Furthermore, the very large production volumes of automotive sub-systems increase the freedom in the mechatronics design process. Instead of being limited to the selection from off-the shelf components, application specific components may be designed. The research presented in this thesis aims at development of an integrated design and optimization methodology for mechatronic modules. The target of the methodology is the conceptual design phase, where the number of design parameters is relatively small. So far, the focus has been on design methods for the electric motor and gearhead, two of the most important components in an actuation module. The thesis presents two methods for design and optimization of motor and gearhead in mechatronic applications. One discrete method, intended for the selection of off-the-shelf components, and one method mainly intended for high volume applications where new application specific components may be designed. Both methods can handle any type of load combination, which is important in mechatronic systems, where the load seldom can be classified as pure inertial or constant speed. Furthermore, design models relating spur gear weight, size and inertia to output torque and gear ratio are presented. It is shown that a gearhead has significantly lower inertia and weight than a motor. The results indicate that it almost always is favorable from a weight and size perspective to use a gearhead. A direct drive configuration may only be lighter for very high speed applications. The main contribution of this thesis is however the motor/gear ratio sizing methods that can be applied to any electromechanical actuation system that requires rotational motion.
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| 43. |
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| 44. |
- Roos, Fredrik, et al.
(author)
-
Optimal Selection of motor and gearhead in mechatronic applications
- 2006
-
In: Mechatronics (Oxford). - : Elsevier BV. - 0957-4158 .- 1873-4006. ; 16:1, s. 63-72
-
Journal article (peer-reviewed)abstract
- A method for the selection of motor and gearhead in mechatronic applications is proposed. The method is applicable to any kind of load and helps to find the optimal motor gearhead combination with respect to output torque, peak power, mass/size and/or cost. The input to the method is the load cycle and component data on candidate motors and gearheads. Output is a set of graphs of all motor/gear ratio combinations that can drive the given load. From these graphs it is easy to read out the peak power, motor torque and energy efficiency for all feasible motor/gear ratio combinations.
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| 45. |
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| 46. |
- Roos, Fredrik, et al.
(author)
-
Relations between size and gear ratio in spur and planetary gear trains
- 2005
-
Reports (other academic/artistic)abstract
- In this report equations for the minimum gear sizes necessary to drive a given load are derived. The equations are based on the Swedish standards for spur gear dimensioning:SS 1863 and SS1871. Minimum size equations for both spur gear pairs and three-wheel planetary gears are presented. Furthermore, expressions for the gear weight and inertiaas function of gear ratio, load torque and gear shape are derived.For a given load torque and gear material, it is possible to retrieve the necessary gearsize, weight and inertia as function of gear ratio. This is useful for gear optimization,but also for optimization of a complete drive system, where the gear size, inertia and weight may affect the requirements on the other parts of the drive system.The results indicate that the Hertzian flank pressure limits the gear size in most cases.The teeth root bending stress is only limiting for very hard steels. Furthermore, then ecessary sizes, weights and inertias are shown to be smaller for planetary gears than for the equivalent pinion and gear configuration. Both these results are consistent with state of practice; planetary gears are commonly known to be compact and to have low inertia.
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| 47. |
- Roos, Fredrik, et al.
(author)
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The influence of gear ratio on performance of electro-mechanical servo systems
- 2006
-
In: Proceedings of the 4th IFAC Symposium on Mechatronic Systems. - : Elsevier BV. - 9783902661173 ; , s. 884-889
-
Conference paper (peer-reviewed)abstract
- The gear ratio's influence on the performance of electromechanical servo systems is analyzed. Even though a gear primarily is used to reduce the actuator size and weight it is important to understand how the gear ratio affects the dynamics of the system. A good choice of gear ratio may improve the control performance while reducing the physical size of the system. It is concluded that for low gear ratios the plant bandwidth is increased with gear ratio. The torque margin of the motor is also shown to increase with gear ratio. Thus, from a control perspective, high gear ratios appear to be better than low.
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| 48. |
- Roos, Fredrik, et al.
(author)
-
Towards a design and optimization methodology for automotive mechatronics
- 2004
-
Conference paper (peer-reviewed)abstract
- The number of mechatronic sub-systems in road vehicles is growing fast. Auxiliary systems that traditionally have been driven by the combustion engine via, for instance, gears, belts or hydraulics are being replaced with electric systems. This development is primarily driven by new and improved functionality, but it is also necessary for the transition to electric and hybrid-electric drive trains. A mechatronic sub-system can be very complex to design and especially to optimize, mainly due to the multi domain characteristics of mechatronics. Usually, in traditional methodologies for mechatronic design, the mechanical structure is determined separate from the controller and also from the electric motor design. To improve the results from the mechatronic development process, a more holistic approach is necessary. The foreseen very large production volumes of mechatronic actuation modules for the automotive industry enable such a holistic approach, where all constituent components can be designed and optimized in one common process. The problem that is being approached in this research is delimited to a methodology for conceptual design and optimization of mechatronic actuation modules. Such modules will be the low level corner stones to achieve advanced functionality such as vehicle stability control and collision avoidance. The goal with the methodology is to capture all relevant system design parameters and properties, from all involved engineering domains, in one single evaluation and optimization process. Some previous work has been done in this area, and many different research groups are working on new methods for mechatronics design. Most of the work is however concentrated on design of system dynamics from a control perspective, i.e. optimization of a system’s dynamic performance. The goal with this research project is to find methods that combine the structure design (statics & dynamics) with the controller design (dynamics). Further, the goal is to derive optimization methods that can find the most optimal system configuration and parameter set with respect to both static and dynamic criteria.
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| 49. |
- Roos, Fredrik, 1976-
(author)
-
Towards a methodology for integrated design of mechatronic servo systems
- 2007
-
Doctoral thesis (other academic/artistic)abstract
- Traditional methods for mechatronics design are often based on a sequential approach, where the mechanical structure is designed first, and then fitted with off-the-shelf electric motors, drive electronics, gearheads and sensors. Finally a control system is designed and optimized for the already existing physical system. Such a design method, that doesn’t consider aspects from a control point of view during the design of the physical system, is unlikely to result in a system with optimal control performance. Furthermore, to separately design and optimize each of the physical components will, from a global perspective, generally not result in a system that is optimal from a weight, size or cost perspective. In order to reach the optimal design of an integrated mechatronic system (mechatronic module) it is necessary to treat the system as a whole, considering aspects from all involved engineering domains concurrently. In this thesis such an approach to integrated design of mechatronic servo systems is presented. A design methodology that considers the simultaneous design of the electric machine, gearhead, machine driver and control system, and therefore enables global optimization, has been developed. The target of the design methodology is conceptual design and evaluation. It is assumed that the load to be driven by the servo system is known and well defined, a load profile describing the wanted load motion and the corresponding torque, is required as input. The methodology can then be used to derive the lightest or smallest possible system that can drive the specified load. Furthermore, the control performance is evaluated and optimized, such that the physical system design and the controller design are integrated. The methodology is based on modelling and simulation. Two types of component models have been developed, static and dynamic models. The static models describe relations between the parameters of the physical components, for example a component’s torque rating as function of its size. The static models are based on traditional design rules and are used to optimize the physical parts of the system. The dynamic models describe the behaviour of the components and are used for control system design and performance optimization. The gear ratio is identified to be the most central design variable when designing and optimizing electromechanical servo systems. The gear ratio directly affects the required size of the gearhead, electric machine and the machine driver. But it has also large influences on the system’s control performance. It is concluded that high gear ratios generally are better from a control point of view than low ratios. A consequence of this is that it is possible, without compromising the control performance, to use less expensive (less accurate) sensors and microprocessors in high gear ratio servo systems, while low gear ratio systems require more expensive hardware. It is also concluded that it is essential to include all performance limiting phenomena, linear as well as non-linear, in this type of integrated analysis. Using for example a linearized system description for controller design, means that many of the most important couplings between control system and physical system design are overlooked.
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| 50. |
- Strandberg, Kristin, et al.
(author)
-
Blood-derived biomarkers correlate with clinical progression in Duchenne muscular dystrophy
- 2020
-
In: Journal of Neuromuscular Diseases. - : IOS Press. - 2214-3599 .- 2214-3602. ; 7:3, s. 231-246
-
Journal article (peer-reviewed)abstract
- Background: Duchenne Muscular Dystrophy is a severe, incurable disorder caused by mutations in the dystrophin gene. The disease is characterized by decreased muscle function, impaired muscle regeneration and increased inflammation. In a clinical context, muscle deterioration, is evaluated using physical tests and analysis of muscle biopsies, which fail to accurately monitor the disease progression. Objectives: This study aims to confirm and asses the value of blood protein biomarkers as disease progression markers using one of the largest longitudinal collection of samples. Methods: A total of 560 samples, both serum and plasma, collected at three clinical sites are analyzed using a suspension bead array platform to assess 118 proteins targeted by 250 antibodies in microliter amount of samples. Results: Nine proteins are confirmed as disease progression biomarkers in both plasma and serum. Abundance of these biomarkers decreases as the disease progresses but follows different trajectories. While carbonic anhydrase 3, microtubule associated protein 4 and collagen type I alpha 1 chain decline rather constantly over time, myosin light chain 3, electron transfer flavoprotein A, troponin T, malate dehydrogenase 2, lactate dehydrogenase B and nestin plateaus in early teens. Electron transfer flavoprotein A, correlates with the outcome of 6-minutes-walking-test whereas malate dehydrogenase 2 together with myosin light chain 3, carbonic anhydrase 3 and nestin correlate with respiratory capacity. Conclusions: Nine biomarkers have been identified that correlate with disease milestones, functional tests and respiratory capacity. Together these biomarkers recapitulate different stages of the disorder that, if validated can improve disease progression monitoring.
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