| 1. |
- Abdellah, Tebani, et al.
(författare)
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Integration of molecular profiles in a longitudinal wellness profiling cohort.
- 2020
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Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- An important aspect of precision medicine is to probe the stability in molecular profiles among healthy individuals over time. Here, we sample a longitudinal wellness cohort with 100 healthy individuals and analyze blood molecular profiles including proteomics, transcriptomics, lipidomics, metabolomics, autoantibodies andimmune cell profiling, complementedwith gut microbiota composition and routine clinical chemistry. Overall, our results show high variation between individuals across different molecular readouts, while the intra-individual baseline variation is low. The analyses show that each individual has a unique and stable plasma protein profile throughout the study period and that many individuals also show distinct profiles with regards to the other omics datasets, with strong underlying connections between the blood proteome and the clinical chemistry parameters. In conclusion, the results support an individual-based definition of health and show that comprehensive omics profiling in a longitudinal manner is a path forward for precision medicine.
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| 2. |
- Abel, Andreas, 1974, et al.
(författare)
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A Graded Modal Dependent Type Theory with a Universe and Erasure, Formalized
- 2023
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Ingår i: Proceedings of the ACM on Programming Languages. - 2475-1421. ; 7:ICFP, s. 920-954
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Tidskriftsartikel (refereegranskat)abstract
- We present a graded modal type theory, a dependent type theory with grades that can be used to enforce various properties of the code. The theory has Pi-types, weak and strong Sigma-types, natural numbers, an empty type, and a universe, and we also extend the theory with a unit type and graded Sigma-types. The theory is parameterized by a modality, a kind of partially ordered semiring, whose elements (grades) are used to track the usage of variables in terms and types. Different modalities are possible. We focus mainly on quantitative properties, in particular erasure: with the erasure modality one can mark function arguments as erasable. The theory is fully formalized in Agda. The formalization, which uses a syntactic Kripke logical relation at its core and is based on earlier work, establishes major meta-theoretic properties such as subject reduction, consistency, normalization, and decidability of definitional equality. We also prove a substitution theorem for grade assignment, and preservation of grades under reduction. Furthermore we study an extraction function that translates terms to an untyped λ-calculus and removes erasable content, in particular function arguments with the "erasable"grade. For a certain class of modalities we prove that extraction is sound, in the sense that programs of natural number type have the same value before and after extraction. Soundness of extraction holds also for open programs, as long as all variables in the context are erasable, the context is consistent, and erased matches are not allowed for weak Sigma-types.
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| 6. |
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| 7. |
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| 9. |
- Danielsson, Oskar, et al.
(författare)
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Flux Distribution in Linear Permanent-Magnet Synchronous Machines Including Longitudinal End Effects
- 2007
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Ingår i: IEEE transactions on magnetics. - 0018-9464 .- 1941-0069. ; 43:7, s. 3197-3201
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the longitudinal ends' influence on the flux distribution in a permanent-magnet linear synchronous machine with an analytic model and with numeric finite-element methods. We derived a general analytic expression, on closed form, from a linear reluctance model. The model reveals that the flux in a linear machine differs from that in a rotating machine in several aspects. The longitudinal ends introduce a pairwise coupled flux pattern, which will behave differently in circuits with odd or even numbers of magnets. In linear machines with an even number of magnets the pairwise coupled flux will spread throughout the whole machine, whereas in linear machines with an odd number of magnets it will be transformed into an equally distributed flux in the middle. The latter case will give rise to a nonsymmetric air gap flux distribution, where every second pole has larger flux. We confirmed the pairwise coupled flux and the nonsymmetric air gap distribution predicted by the analytic model by finite-element simulations. We noted additional effects when nonlinear behavior of the steel is taken into account. We conclude that saturation counteracts the pairwise coupled flux pattern at the longitudinal ends. Again, a nonsymmetric air gap flux distribution occurs as the pairwise coupled flux is transformed into an equally coupled flux. The pairwise coupling of the flux and the nonsymmetric air gap flux distribution give rise to a number of secondary effects, which we discuss.
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| 10. |
- Danielsson, Oskar, 1991, et al.
(författare)
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Influence of body stiffness on vehicle dynamics characteristics
- 2016
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Ingår i: Dynamics of vehicles on roads and tracks. 24th Symposium of the International-Association-for-Vehicle-System-Dynamics (IAVSD), 2015. Graz; Austria, 17-21 August 2015. - : CRC Press. ; , s. 45-56
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Konferensbidrag (refereegranskat)abstract
- Body stiffness is one of is one of the characteristics of a passenger car affecting the handling, steering and ride comfort characteristics of the vehicle, but so far only limited aspects of mainly steering and handling has been analyzed. In this paper an extensive and detailed analysis of the influence of body stiffness on steering, handling and ride comfort is performed using a combination of laboratory and track testing of a physical prototype as well as sub-system and full vehicle multi-body simulation and finite element analysis. In this study it is found that the on-center, frequency response and primary ride are mostly affected by changes in body stiffness. For example, the torsional stiffness should be increased in order to improve roll balance in ride maneuvers. It is also found that the front and rear lateral stiffness should be raised in order to reduce dead band and steering wheel angle to yaw rate phase lags. Furthermore, maneuvers that combine handling and ride effects are proven to be particularly useful for defining body stiffness targets related to vehicle dynamics effects and one such maneuver is developed and evaluated in this paper. Finally, it is found that the difference between a rigid and flexibly vehicle model can be up to 13% for certain metrics, meaning that assuming a rigid body can be a significant oversimplification.
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| 11. |
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| 13. |
- Danielsson, Oskar, et al.
(författare)
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Study of a Longitudinal Flux Permanent Magnet Linear Generator for Wave Energy Converters
- 2006
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Ingår i: International Journal of Energy Research. - : Hindawi Limited. - 0363-907X .- 1099-114X. ; 30:14, s. 1130-1145
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Tidskriftsartikel (refereegranskat)abstract
- A directly coupled linear permanent magnet generator of longitudinal flux-type is investigated. The generator will be used for power take-off in a wave energy converter. A combined field- and circuit model, solved by a time stepping finite element technique, is used to model and analyse the electromagnetic behaviour of the machine. A large number of simulations form the basis of a design study where the influence of armature current level, number of cables per slot, and pole width is investigated with respect to efficiency, generator size, and the load angle. A case study is performed for a chosen generator design. The electromagnetic behaviour is examined both for nominal load and for overloads. The generator has a nominal output power of 10 kW for a constant piston speed of 0.7 m s(-1). The electromagnetic efficiency at nominal load is 86.0%, the load angle 6.6 degrees, and the power fluctuation 1.3%. At 300% overload the load angle barely exceeds 12 degrees and the cable temperature is below 25 degrees C provided that the stator back is thermally connected to the sea water. The numerical calculations have been verified for small speeds by experiments.
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| 14. |
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| 15. |
- Danielsson, Oskar, 1975-
(författare)
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Wave Energy Conversion : Linear Synchronous Permanent Magnet Generator
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis studies the electric aspects of a linear synchronous permanent magnet generator. The generator is designed for use in a wave energy converter, which determines the fundamental requirements of the generator. The electromagnetic properties of the generator are investigated with a finite element based simulation tool. These simulations formed the base of the design and construction of a laboratory prototype. Several experiments where conducted on the prototype generator. The results verify at large the simulation tool. However, a difference between the measured and simulated air gap flux was discovered. This was attributed to the longitudinal ends of the generator, which are ignored in the simulation tool. Experiences from the construction, and further finite element studies, led to a significant change in the support structure of the first offshore prototype generator. A complete wave energy converter was constructed and launched, the 13th of March, on the west coast of Sweden. A study of the load resistance impact on the power absorption has been carried out. An optimal load interval, with regard to power absorption, has been identified. Furthermore, the generator has proofed to withstand short term overload several times larger than the nominal load. Finally, the longitudinal ends’ influence on the flux distribution was investigated with an analytical model, as well as finite element simulations. A possible problem with large induction of eddy currents in the actuator back steel was identified.This work is a part of a larger project, which aims do develop a viable wave energy conversion system.
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| 16. |
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| 17. |
- Henfridsson, Urban, et al.
(författare)
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Wave energy potential in the Baltic Sea and the Danish part of the North Sea, with reflections on the Skagerrak
- 2007
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Ingår i: Renewable energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; 32:12, s. 2069-2084
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Tidskriftsartikel (refereegranskat)abstract
- Wave power, along with renewable energy-generating sources like tides and streams, is underestimated considering its advantageous physical properties and predictability. This paper examines possible examples of wave power installations in the Baltic Sea and the Danish part of the North Sea. Hindcasting data is used allowing estimations of wave energy generated and results show promising areas in the North Sea, but also several parts of the Baltic Sea are of interest. The study is based upon linear generator technique, placed on the seabed using point-absorbers arranged in arrays of up to several thousand units. The study aims at showing the physical possibilities of wave energy, including economical feasibility and environmental advantages of wave energy even in moderate wave climates. With discussion from two examples in the Baltic Sea, one in the Danish North Sea and a new pilot study site in the Swedish part of Skagerrak, this study show feasible illustrations of wave energy takeouts. Project examples vary in size due to distance to grid, grid voltage, and may thus be economically feasible. Examples also show considerations in societal and nature conservation matters, including aspects such as industrial and military interests, archaeological or marine reserves and local geology. The authors conclude that wave energy electric conversion is an option that needs more attention and which has several advantages compared to conventional renewable sources. Sound engineering, in combination with producer, consumer and broad societal perspective is advised for a sustainable development of wave energy conversion.
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| 18. |
- Leijon, Mats, et al.
(författare)
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An electrical approach to wave energy conversion
- 2006
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Ingår i: Renewable energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; :31, s. 1309-1319
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Tidskriftsartikel (refereegranskat)abstract
- Motions in nature, for example ocean waves, can play a significant role in tomorrow's electricity production, but the constructions require adaptations to its media. Engineers planning hydropower plants have always taken natural conditions, such as fall height, speed of flow, and geometry, as basic design parameters and constraints in the design. The present paper describes a novel approach for electric power conversion of the vast ocean wave energy. The suggested linear electric energy converter is adapted to the natural wave motion using straightforward technology. Extensive simulations of the wave energy concept are presented, along with results from the experimental setup of a multisided permanent magnet linear generator. The prototype is designed through systematic electromagnetic field calculations. The experimental results are used for the verification of measurements in the design process of future full-scale direct wave energy converters. The present paper, describes the energy conversion concept from a system perspective, and also discusses the economical and some environmental considerations for the project.
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| 19. |
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| 20. |
- Leijon, Mats, et al.
(författare)
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Wave Energy from the North Sea : Experiences from the Lysekil Research Site
- 2008
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Ingår i: Surveys in geophysics. - : Springer Science and Business Media LLC. - 0169-3298 .- 1573-0956. ; 29:3, s. 221-240
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Forskningsöversikt (refereegranskat)abstract
- This paper provides a status update on the development of the Swedish wave energy research area located close to Lysekil on the Swedish West coast. The Lysekil project is run by the Centre for Renewable Electric Energy Conversion at Uppsala University. The project was started in 2004 and currently has permission to run until the end of 2013. During this time period 10 grid-connected wave energy converters, 30 buoys for studies on environmental impact, and a surveillance tower for monitoring the interaction between waves and converters will be installed and studied. To date the research area holds one complete wave energy converter connected to a measuring station on shore via a sea cable, a Wave Rider™ buoy for wave measurements, 25 buoys for studies on environmental impact, and a surveillance tower. The wave energy converter is based on a linear synchronous generator which is placed on the sea bed and driven by a heaving point absorber at the ocean surface. The converter is directly driven, i.e. it has no gearbox or other mechanical or hydraulic conversion system. This results in a simple and robust mechanical system, but also in a somewhat more complicated electrical system.
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| 21. |
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| 22. |
- Skog, Oskar, et al.
(författare)
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Expression of Human Leukocyte Antigen Class I in Endocrine and Exocrine Pancreatic Tissue at Onset of Type 1 Diabetes
- 2015
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Ingår i: American Journal of Pathology. - : Elsevier BV. - 0002-9440 .- 1525-2191. ; 185:1, s. 129-138
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Tidskriftsartikel (refereegranskat)abstract
- The cause of type 1 diabetes remains unknown. To dissect the Link between hyperexpression of human leukocyte antigen (HLA) class Ion the islet cells, we examined its expression in subjects with recent-onset type 1 diabetes. IHC showed seemingly pronounced hyperexpression in subjects with recent-onset type 1 diabetes, as well as in some nondiabetic subjects. In all subjects, HLA class I expression on exocrine tissue was Low. However, no difference in the level of HLA class I expression was found between islet and exocrine tissue using Western blot, flow cytometry, real-time quantitative PCR, or RNA sequencing analyses. Also, the Level of HLA class I expression on the messenger level was not increased in islets from subjects with recent-onset type 1 diabetes compared with that in nondiabetic subjects. Consistently, the HLA class I specific enhanceosome (NLRC5) and related transcription factors, as well as interferons, were not enhanced in islets from recent-onset type 1 diabetic subjects. In conclusion, a discrepancy in HLA class I expression in islets assessed by IHC was observed compared with that using quantitative techniques showing similar expression of HLA class I in islets and exocrine tissue in subjects with recent-onset type 1 diabetes, nor could any differences be found between type 1 diabetic and nondiabetic subjects. Results presented provide important clues for a better understanding on how this complex disease develops.
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| 23. |
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| 24. |
- Stålberg, Magnus, et al.
(författare)
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Influence of Generator Damping on Peak Power and Variance of Power for a Direct Drive Wave Energy Converter
- 2008
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Ingår i: Journal of Offshore Mechanics and Arctic Engineering-Transactions of The Asme. - : ASME International. - 0892-7219 .- 1528-896X. ; 130:3, s. 031003-
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Tidskriftsartikel (refereegranskat)abstract
- The first offshore prototype of a wave energy converter system has been launched off the Swedish west coast. The concept is based on a point absorber directly coupled to a linear generator located on the ocean floor. The wave energy converter is part of a research project that will study the electric system of ten units forming a small farm of wave power plants as they are linked and connected to an electric grid. A full scale farm will consist of a large number of interconnected units. The chosen direct drive system reduces the mechanical complexity of the converter but has repercussions on the electric system. The output from the generator will vary with the speed of the point absorber, leading to large fluctuations of power on the second scale. This has implications on both the individual generator and on the system as a whole. The hydrodynamic behavior of the point absorber depends, to a large extent, on the damping of the generator. The damping, in turn, can be remotely controlled by changing the load resistance. It has previously been shown that this has a large influence on the power absorbed by the wave energy converter. This paper investigates the peak power, the translator speed, and the variance of the power at different sea states and for different levels of damping. The peak power has an impact on the design of the generator and the required ability, for a single unit, to handle electric overloads. The momentum of the translator is directly proportional to its speed. The speed is thus important for the design of the end stop. The variance of the power of one unit will have an impact on the farm system behavior. The study is based on two and a half months of experimental measurements on the prototype wave energy converter and a wave measurement buoy. The aim is to analyze whether load control strategies may influence the dimensioning criteria for the electric system and the generator. The results are compared to previously investigated relationships between the absorbed mean power and the load resistance as a function of sea state. In the study, it was found that the maximum power is approximately proportional to the average power, while the maximum translator speed and standard deviation decrease as the damping factor is increased.
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| 25. |
- Stålberg, Magnus, et al.
(författare)
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Influence of Generator Damping on Peak Power and Variance of Power for a Direct Drive Wave Energy Coverter
- 2007
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Ingår i: Proceedings of the 26th International Conference on Offshore Mechanics and Arctic Engineering, Vol 5. - 9780791842713 ; , s. 501-504
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Konferensbidrag (refereegranskat)abstract
- The first full-scale offshore prototype of a novel wave energy converter system has been launched off the Swedish west coast. The concept is based on a point absorber directly coupled to a linear generator located on the ocean floor. The wave energy converter is part of a research project that will study the electrical system of 10 units forming a small farm of wave power plants as they are linked and connected to an electric grid. A full scale farm will consist of a large number of interconnected units. The chosen direct drive system reduces the mechanical complexity of the converter but has repercussions on the electrical system. The output from the generator will vary with the speed of the point absorber, leading to large fluctuations of power on the second scale. This has implications on both the individual generator and on the system as a whole. The hydrodynamic behavior of the point absorber depends, to a large extent, on the damping of the generator. The damping, in turn, can be controlled remotely by changing the load resistance. It has previously been shown that this has a large influence on the power absorbed by the wave energy converter. This paper investigates the peak power, the translator speed and the variance of the power at different sea states and for different levels of damping. The peak power has an impact on the design of the generator and the required ability, for a single unit, to handle electrical overloads. The speed of the translator is directly proportional to its momentum. It is thus important for the design of the end stop. The variance of the power of one unit will have an impact on the farm system behavior. The study is based on two and a half months of experimental measurements on the prototype wave energy converter and a wave measurement buoy. The aim is to analyze whether load control strategies may influence the dimensioning criteria for the electrical system and the generator. The results are compared with previously investigated relationships between absorbed mean power and load resistance as a function of sea state. In the study it was found that the maximum power is approximately proportional to the average power while maximum translator speed and standard deviation decrease as the damping factor is increased.
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| 26. |
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| 27. |
- Thörn, Richard, et al.
(författare)
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Improved survival in at-risk patients undergoing surveillance for hepatocellular carcinoma : a nationwide Swedish register-based study
- 2023
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Ingår i: Journal of Hepatocellular Carcinoma. - : Dove Medical Press. - 2253-5969. ; 10, s. 1573-1586
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Surveillance for hepatocellular carcinoma (HCC) is recommended in at-risk patients, but its effectiveness in Western populations has been questioned. The purpose was to evaluate the effect of surveillance in patients with HCC in a Northern European setting.Patients and Methods: Data on patients diagnosed with HCC between 2009 and 2019 were collected from the nationwide Swedish National Registry for Tumors of the Liver and Bile Ducts (SweLiv). Patients who had undergone HCC surveillance were compared to those who had not (but had an obvious indication for surveillance, ie, liver cirrhosis or hepatic porphyria and an age of ≥50 years) regarding etiology, tumor burden, presence of extrahepatic spread, treatment and lead-time adjusted overall survival.Results: A total of 4979 patients with index HCC were identified and information regarding surveillance was available in 4116 patients. Among these, 1078 had got their HCC diagnosis during surveillance, whereas 1647 had been diagnosed without surveillance despite a presumed indication. The most common underlying etiologies for HCC were hepatitis C (28.2%) and alcoholic liver disease (26.9%), and 94.8% had cirrhosis. The surveillance cohort more frequently met the University of California San Francisco-criteria (79% vs 53%, p <0.001), more often received a potentially curative treatment (62% vs 28%, p <0.001) and had less extrahepatic spread (7.6% vs 22.4% p <0.001). After adjustment for lead-time bias (sojourn time of 270 days), the surveillance group had a significantly longer estimated median survival time than the non-surveillance group (34 months vs 11 months, p <0.001). A multivariable cox regression analysis showed an adjusted hazard ratio of 0.59 (95% CI 0.51–0.67) in favor of surveillance.Conclusion: Surveillance for HCC in at-risk patients is associated with diagnosis at an earlier tumor stage, treatment with curative intent and with improved lead-time adjusted overall survival. These findings encourage HCC surveillance of at-risk patients also in a Western population.
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| 28. |
- Waters, Rafael, et al.
(författare)
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Experimental results from sea trials of an offshore wave energy system
- 2007
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 90:3, s. 034105-
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Tidskriftsartikel (refereegranskat)abstract
- A full-scale prototype of a wave power plant has been installed off the Swedish west coast and the overall wave energy converter concept has been verified. Initial results have been collected and significant insights discovered. Energy absorption dependency on load as well as output voltage and power is demonstrated. It is shown that great overload capability of the directly driven linear generator is critical, and indicated that, for resistive loads, optimal load does not vary with wave climate. Future grid supplying energy production would necessitate parks of wave power plants in order to reduce power fluctuations.
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| 29. |
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| 30. |
- Waters, Rafael, et al.
(författare)
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Measuring air gap width of permanent magnet linear generators using search coil sensor
- 2007
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 101:2, s. 024518-
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Tidskriftsartikel (refereegranskat)abstract
- A concept for a wave power plant is being developed at the Centre for Renewable Electric Energy Conversion at the A˚ngström Laboratory at Uppsala University. The concept is based on a permanent magnet linear generator placed on the seabed, directly driven by a surface following buoy. Critical for the survival of the generator is that the air gap between the moving and static parts of the generator is constantly fixed at the designed width to prevent the moving and static parts from connecting during operation. This paper shows the design and evaluation of an inductive sensor for measuring the air gap width during generator operation. In order to survive during years on the seafloor inside the wave power plants, the sensor has deliberately been chosen to be a passive component, as well as robust and compact. A coil etched on a printed circuit board, i.e., a search coil, was the chosen basis for the sensor. The sensor has been tested on an existing test rig of a wave power plant and the results have been compared with finite element simulations.The results show that a search coil magnetic sensor etched on a printed circuit board is a suitable concept for measuring the air gap width. Experimentally measured and theoretically calculated sensor signals show very good agreement. The setup has a sensitivity of +/-0.4 mm in the range of 4-9.5 mm air gap. The potential for future improvements of the sensitivity is considerable.
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| 31. |
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