| 1. |
- Ameur, Adam, et al.
(författare)
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SweGen : a whole-genome data resource of genetic variability in a cross-section of the Swedish population
- 2017
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Ingår i: European Journal of Human Genetics. - : NATURE PUBLISHING GROUP. - 1018-4813 .- 1476-5438. ; 25:11, s. 1253-1260
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Tidskriftsartikel (refereegranskat)abstract
- Here we describe the SweGen data set, a comprehensive map of genetic variation in the Swedish population. These data represent a basic resource for clinical genetics laboratories as well as for sequencing-based association studies by providing information on genetic variant frequencies in a cohort that is well matched to national patient cohorts. To select samples for this study, we first examined the genetic structure of the Swedish population using high-density SNP-array data from a nation-wide cohort of over 10 000 Swedish-born individuals included in the Swedish Twin Registry. A total of 1000 individuals, reflecting a cross-section of the population and capturing the main genetic structure, were selected for whole-genome sequencing. Analysis pipelines were developed for automated alignment, variant calling and quality control of the sequencing data. This resulted in a genome-wide collection of aggregated variant frequencies in the Swedish population that we have made available to the scientific community through the website https://swefreq.nbis.se. A total of 29.2 million single-nucleotide variants and 3.8 million indels were detected in the 1000 samples, with 9.9 million of these variants not present in current databases. Each sample contributed with an average of 7199 individual-specific variants. In addition, an average of 8645 larger structural variants (SVs) were detected per individual, and we demonstrate that the population frequencies of these SVs can be used for efficient filtering analyses. Finally, our results show that the genetic diversity within Sweden is substantial compared with the diversity among continental European populations, underscoring the relevance of establishing a local reference data set.
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| 2. |
- Isaksson, Patrik, et al.
(författare)
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Elasto-hydrodynamic simulation of complex geometries in hydraulic motors
- 2008
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Ingår i: Proceedings of NORDTRIB 2008, 13th Nordic Symposium on Tribology. - Tampere : Tampere University of Technology. - 9789521519598
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Konferensbidrag (refereegranskat)abstract
- As many other machines, the radial piston hydraulic motor contains a lot of tribological interfaces. One important area is the piston assembly and the journal bearing contact between the piston and cam roller. There exists good models to describe the performance of simpler geometries such as journal bearings, but when put into a system or when having a more complex geometry, the models do not apply very well. To be able to predict the tribological performance of such components, it is important to have a model that is able to include the real geometry and the properties of the system. A simulation model of the piston assembly in Hägglunds Compact hydraulic motor was built using FE software which made it easy to include the complex geometries. The model includes the deformation of the piston. The hydrodynamics is solved by using Reynolds equation. Density/pressure and viscosity/pressure dependency for the oil are included. The whole model was solved with the built in solvers in the software. Simulation results such as friction, hydrodynamic pressure and oil leakage was compared with test results. Good agreement between simulation and tests shows that this kind of model can be a useful tool in development and optimization of tribological systems.
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| 3. |
- Isaksson, Patrik, et al.
(författare)
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Elasto-hydrodynamic simulation of complex geometries in hydraulic motors
- 2009
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Ingår i: Tribology International. - : Elsevier BV. - 0301-679X .- 1879-2464. ; 42:10, s. 1418-1423
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Tidskriftsartikel (refereegranskat)abstract
- As many other machines, the radial piston hydraulic motor contains a lot of tribological interfaces. One important area is the piston assembly and the journal bearing contact between the piston and cam roller. There exists good models to describe the performance of simpler geometries such as journal bearings, but when put into a system or when having a more complex geometry, the models do not apply very well. To be able to predict the tribological performance of such components, it is important to have a model that is able to include the real geometry and the properties of the system.A simulation model of the piston assembly in Hägglunds Compact hydraulic motor was built using FE software which made it easy to include the complex geometries. The model includes the deformation of the piston. The hydrodynamics is solved by using Reynolds equation.Density/pressure and viscosity/pressure dependency for the oil are included.Simulation results such as friction, hydrodynamic pressure and oil leakage was compared with test results. Good agreement between simulation and tests shows that this kind of model can be a useful tool in development and optimization of tribological systems.
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| 4. |
- Isaksson, Patrik, et al.
(författare)
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The influence of surface roughness on friction in a flexible hybrid bearing
- 2011
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Ingår i: Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology. - : SAGE Publications. - 1350-6501 .- 2041-305X. ; 225:J10, s. 975-985
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Tidskriftsartikel (refereegranskat)abstract
- The effect of surface roughness on friction in all lubrication regimes is studied for a flexible hybrid bearing of a radial piston hydraulic motor. The effect is studied by performing experiments in a specially designed test rig and numerical simulations of the real measured surface topographies of the bearings. The simulations are performed with a two-scale model where surface roughness is treated on a local asperity level by homogenized flow factors and a global scale where the bearing structure is included. Three bearings with different surface topographies are included in the study and both experimentally measured and simulated friction are analysed for each of them. Comparison of friction predicted by the model and experimentally measured friction is performed and it reveals that the model is a valuable tool for analysing the effect of surface roughness in this type of bearing
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| 5. |
- Lindstrand, Anna, et al.
(författare)
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From cytogenetics to cytogenomics : whole-genome sequencing as a first-line test comprehensively captures the diverse spectrum of disease-causing genetic variation underlying intellectual disability
- 2019
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Ingår i: Genome Medicine. - : BMC. - 1756-994X. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundSince different types of genetic variants, from single nucleotide variants (SNVs) to large chromosomal rearrangements, underlie intellectual disability, we evaluated the use of whole-genome sequencing (WGS) rather than chromosomal microarray analysis (CMA) as a first-line genetic diagnostic test.MethodsWe analyzed three cohorts with short-read WGS: (i) a retrospective cohort with validated copy number variants (CNVs) (cohort 1, n=68), (ii) individuals referred for monogenic multi-gene panels (cohort 2, n=156), and (iii) 100 prospective, consecutive cases referred to our center for CMA (cohort 3). Bioinformatic tools developed include FindSV, SVDB, Rhocall, Rhoviz, and vcf2cytosure.ResultsFirst, we validated our structural variant (SV)-calling pipeline on cohort 1, consisting of three trisomies and 79 deletions and duplications with a median size of 850kb (min 500bp, max 155Mb). All variants were detected. Second, we utilized the same pipeline in cohort 2 and analyzed with monogenic WGS panels, increasing the diagnostic yield to 8%. Next, cohort 3 was analyzed by both CMA and WGS. The WGS data was processed for large (>10kb) SVs genome-wide and for exonic SVs and SNVs in a panel of 887 genes linked to intellectual disability as well as genes matched to patient-specific Human Phenotype Ontology (HPO) phenotypes. This yielded a total of 25 pathogenic variants (SNVs or SVs), of which 12 were detected by CMA as well. We also applied short tandem repeat (STR) expansion detection and discovered one pathologic expansion in ATXN7. Finally, a case of Prader-Willi syndrome with uniparental disomy (UPD) was validated in the WGS data.Important positional information was obtained in all cohorts. Remarkably, 7% of the analyzed cases harbored complex structural variants, as exemplified by a ring chromosome and two duplications found to be an insertional translocation and part of a cryptic unbalanced translocation, respectively.ConclusionThe overall diagnostic rate of 27% was more than doubled compared to clinical microarray (12%). Using WGS, we detected a wide range of SVs with high accuracy. Since the WGS data also allowed for analysis of SNVs, UPD, and STRs, it represents a powerful comprehensive genetic test in a clinical diagnostic laboratory setting.
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| 6. |
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| 7. |
- Nilsson, Daniel, et al.
(författare)
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Effects of area ratio and nature of surfaces on scuffing in lubricated contacts
- 2009
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Ingår i: Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology. - 1350-6501 .- 2041-305X. ; 223:3, s. 445-455
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Tidskriftsartikel (refereegranskat)abstract
- Heavily loaded moving machine components encounter severe tribological problems. Typical examples include piston and cylinder contacts in a hydraulic motor. Piston and cylinder bore contacts invariably operate in boundary lubrication regime and the risk for seizure of these contacts is high particularly when lubricated with low-viscosity lubricants. The piston assembly in a radial piston hydraulic motor has conformal (area) contact. In this work, these contacts have been simulated in the laboratory by using a thrust washer test configuration. The influence of area ratio, nature of contacting surfaces, and speed on scuffing has been investigated by using a factorial design of experiments approach. The influence of area ratio on wear at lower speed has also been studied. The results have revealed that the surface power, or μpv-value, at scuffing varies by 3-4 times when the area ratio was increased from 8 to 72 per cent. The running-in wear tests have shown that running-in of the upper and lower specimens also varies with the area ratio. During the first 30 s the upper specimen is polished with low area ratio, whereas the lower specimen is polished with high area ratio. The surface temperature was estimated by using finite-element calculation and it was found to be similar prior to scuffing for both 8 and 72 per cent area ratios at 1.7 m/s sliding speed. The comparison of the results with the actual motor tests shows that an area ratio of 24 per cent seems to simulate the piston-cylinder contact better.
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