| 1. |
- Beecham, Ashley H, et al.
(författare)
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Analysis of immune-related loci identifies 48 new susceptibility variants for multiple sclerosis.
- 2013
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Ingår i: Nature genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 45:11, s. 1353-60
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Tidskriftsartikel (refereegranskat)abstract
- Using the ImmunoChip custom genotyping array, we analyzed 14,498 subjects with multiple sclerosis and 24,091 healthy controls for 161,311 autosomal variants and identified 135 potentially associated regions (P < 1.0 × 10(-4)). In a replication phase, we combined these data with previous genome-wide association study (GWAS) data from an independent 14,802 subjects with multiple sclerosis and 26,703 healthy controls. In these 80,094 individuals of European ancestry, we identified 48 new susceptibility variants (P < 5.0 × 10(-8)), 3 of which we found after conditioning on previously identified variants. Thus, there are now 110 established multiple sclerosis risk variants at 103 discrete loci outside of the major histocompatibility complex. With high-resolution Bayesian fine mapping, we identified five regions where one variant accounted for more than 50% of the posterior probability of association. This study enhances the catalog of multiple sclerosis risk variants and illustrates the value of fine mapping in the resolution of GWAS signals.
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| 2. |
- Riggio, Mariapaola, et al.
(författare)
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In situ assessment of structural timber using non-destructive techniques
- 2014
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Ingår i: Materials and Structures/Materiaux et Constructions. - : Springer Science and Business Media LLC. - 1359-5997. ; 47:5, s. 749-766
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Tidskriftsartikel (refereegranskat)abstract
- This paper summarizes the test recommendations for selected non-destructive testing (NDT) techniques as developed by members of the RILEM Technical Committee AST 215 “In situ assessment of structural timber”. The recommendations cover visual inspection, moisture content determination, species identification, digital radioscopy, and ground penetrating radar. The paper includes a matrix of common NDT to assess structural timber. The discussion of each technique is intended to provide users with sufficient information to understand the theoretical basis, typical equipment set up, and basic capabilities and limitations.
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| 3. |
- ERICSSON, KARIN, et al.
(författare)
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NON-DESTRUCTIVE TESTING OF THE HISTORIC TIMBER ROOF STRUCTURES OF THE NATIONAL MUSEUM IN STOCKHOLM, SWEDEN
- 2018
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Ingår i: International Journal of Heritage Architecture. - 2058-833X .- 2058-8321. ; 2:2, s. 218-229
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Tidskriftsartikel (refereegranskat)abstract
- The National Museum in Stockholm is Sweden’s leading museum of art and design. Behind the now closed doors of the National Museum and its construction coverings a renovation project is taking place, which began in 2014 and will be completed in 2018. The renovation project will create a modern museum, a brighter atmosphere for the arts and for its visitors. Part of the renovation project was to de-sign and upgrade the timber roof structure for new loads according to Eurocode 5. As the roof structure was originally built in 1860, it was important to evaluate the condition and mechanical properties of the original load-bearing timber members. The roof structure, which is of main interest, comprises roof trusses and lantern structures.The main aim of the project regarding the timber roof structure in the National Museum was a safety verification in both the ultimate state (ULS) and the serviceability limit state (SLS). The preliminary capacity calculations for the roof structure showed that the roof members were under the new load conditions (with increased loads due to security and environmental requirements) utilized above 100%. Therefore, an investigation into the properties of the old timber members and connections was of vital importance. The need for non-destructive testing (NDT) of structural timber is well known under the name of strength grading and the concept has been used for many years to classify timber with respect to mechanical performance. The stress wave technique used in the project was based on commercial instruments such as FAKOPP®. The timber quality investigation for the attic roof structures showed that the material was generally in very good condition. As a result, according to SS-EN 338-2009, the timber strength could be assigned strength class C27–C30. Based on the results of the investigation, further design of strengthening works and refurbishment of the roof structure were being undertaken
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| 4. |
- Honfi, Daniel, et al.
(författare)
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Decision support for maintenance and upgrading of existing bridges
- 2017
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Ingår i: IABSE Conference, Vancouver 2017. - : International Association for Bridge and Structural Engineering (IABSE). - 9783857481536 ; 109, s. 336-345, s. 336-345
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Konferensbidrag (refereegranskat)abstract
- Maintenance of transportation infrastructure assets can be relatively expensive, since it does not only include the direct cost of interventions, but also the indirect consequences of traffic disruptions. To make optimal decisions about maintenance actions, including rehabilitation and upgrading, reliable information about the performance of existing structures is needed. However, obtaining such information might require significant efforts and can be done in various ways. The purpose of an ongoing Swedish research project BIG BRO is to develop a framework for a decision support methodology that can be used for implementing maintenance strategies for bridges on a rational basis. The present paper provides a brief overview about the project as well as describes some of the ongoing work.
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| 5. |
- Honfi, Daniel, et al.
(författare)
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Inspection and monitoring of bridges in Sweden
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report provides an overview about recent research activities and current practice concerning inspection and monitoring of the structural performance of bridges and the related decision-making process. A brief review of common methods of collecting information on structural performance of bridges is presented, followed by a description of the use of the information collected in structural analysis and maintenance planning. An overview about the state of the art is given including recent scientific developments. Finally, the current Swedish practice for bridge management is presented.
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| 6. |
- Honfi, Daniel, et al.
(författare)
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Rational maintenance of timber bridges
- 2017
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Ingår i: Conference proceedings, ICTB 2017. 3rd International Conference on Timber Bridges.
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Konferensbidrag (refereegranskat)abstract
- The present paper provides some ideas about how decisions concerning maintenance of timber bridges should be made in a rational way. First, a brief discussion is provided concerning the evolution of maintenance strategies in general and it is suggested that maintenance of timber bridges should follow a risk-based approach. Then the discussion moves on to the condition assessment of timber bridges with a main focus on inspection and monitoring. The use of non-destructive testing methods and structural health monitoring is highlighted with regard to collecting useful information for maintenance decisions. It is argued that the information collected, should be used in a Bayesian decision analysis framework, which is especially useful in quantifying to value of information and thus the worth of various inspection and monitoring alternatives.
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| 7. |
- Ilharco, T., et al.
(författare)
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Assessment of timber floors by means of non-destructive testing methods
- 2015
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Ingår i: Construction and Building Materials. - : Elsevier BV. - 0950-0618. ; 101, s. 1206-1214
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Tidskriftsartikel (refereegranskat)abstract
- In the process of rehabilitation of built heritage, the preservation of timber floors is an essential issue. These structures have characteristics that are not entirely known, namely the connections between elements, the load distribution between beams, the importance of secondary elements, such as struts and floorboard, for the attenuation of vibrations and reduction of deformations of the floor, etc. If properly analysed and considered, these aspects can contribute to upcoming well-succeeded interventions, improving the global behaviour of the floors and, consequently, of the buildings. One of the focuses of the present paper is the assessment of the global behaviour of timber floors by means of dynamic analysis, which is one of the non destructive tests (NDT) used to evaluate the reference properties of the wood. In particular, this technique allows estimating the timber floors' stiffness and, consequently, assessing their efficiency and integrity. Furthermore, the paper focuses on the use of other NDT methods, namely involving stress-wave timing, X-ray and resistance drilling, which can provide very useful information about these characteristics. The information obtained with the combined NDT allows a better understanding of the timber floors behaviour and the implementation of more efficient rehabilitation and (or) strengthening techniques
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| 8. |
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| 9. |
- Koenig, Thomas, et al.
(författare)
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Bicameral conflict resolution in the European Union : An empirical analysis of conciliation committee bargains
- 2007
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Ingår i: British Journal of Political Science. - 0007-1234 .- 1469-2112. ; 37:2, s. 281-312
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Tidskriftsartikel (refereegranskat)abstract
- This article is a study of bicameral conflict resolution between the Council and the European Parliament in the European Union, which has established a bicameral conciliation process under the co-decision procedure. Scholars commonly agree that the European Parliament has gained power under the co-decision procedure, but the impact of the conciliation process on the power distribution between the Council and the European Parliament remains unclear. The scholarly debate suggests that the power of the institutional actors depends on their proximity to the status quo, the (im-)patience and the specific preference distribution of the institutional actors, although most analyses assume that the Commission plays an insignificant role. Using an ordered probit model, this study examines the power distribution between the two institutional actors, the factors for their bargaining success and the role of the Commission in the period between 1999 and 2002. The findings show that the European Parliament wins most conflicts, but that the Council is more successful in multi-dimensional disputes. The results confirm some theoretical claims made in the literature, such as the importance of the status quo location and of preference cohesiveness. However, they also reject a major assumption in the literature on the irrelevance of the Commission in the conciliation process, which we show to have an influential informational position for parliamentary success.
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| 10. |
- Lechner, Thomas, 1979, et al.
(författare)
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Assessment of Density in Timber Using X-Ray Equipment
- 2013
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Ingår i: International Journal of Architectural Heritage. - : Informa UK Limited. - 1558-3058 .- 1558-3066. ; 7:4, s. 416-433
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Tidskriftsartikel (refereegranskat)abstract
- Wood density has a strong relationship with several mechanical properties, such as strength and stiffness. An x-ray image calibration procedure, which enables the determination of density properties for the in situ assessment of timber structures, has been developed. This nondestructive method is useful for evaluating the internal condition for global assessments of the structure. For this study, 14 wood specimens with significant density differences were exposed to x-rays. The specimens were set up in a number of image configurations. The images were analyzed and evaluated using an image toolbox. A similar procedure was applied to six built-up blocks with different thicknesses in order to calibrate the thickness of the specimens. Finally, a calibration wedge was set up to verify the procedure. The density calibration procedure from x-ray images was verified on a timber beam specimen, resulting in good agreement and an average accuracy of 97%. The values obtained from the image calibration presented a very good linear correlation between the measured density and the grayscale from x-ray images with coefficients of determination (R-2) ranging from 0.90-0.98. The main advantages compared with conventional techniques are the detection and quantification of internal damage, defects, disturbances, and deterioration that may reduce the mechanical properties of the structure. This study shows good potential when it comes to the development of a viable tool for in situ assessments of timber structures. This technique could be used indirectly in analyses of structural behavior.
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| 11. |
- Lechner, Thomas, 1979, et al.
(författare)
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In situ assessment of the timber floor structure of the Skansen Lejonet fortification, Sweden
- 2014
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Ingår i: Construction and Building Materials. - : Elsevier BV. - 0950-0618. ; 58, s. 85-93
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Tidskriftsartikel (refereegranskat)abstract
- Historical structures represent part of the cultural heritage of every nation and societies pay considerable attention to their preservation and maintenance. In historical structures, it is essential to preserve the original structure to the greatest degree possible. It is therefore of great importance to adopt structural health monitoring techniques to assess the remaining load-bearing capacity of timber structures. The main aim of this study was to examine the structural soundness and performance of the timber floor structures in Skansen Lejonet. Non-destructive testing (NDT) was used to evaluate mechanical properties and the general condition, without interfering with the structural integrity. It has been shown that the general structural condition and performance is good and fulfils the requirements for the intended use of the structure both in the past and at the present time, according to Eurocode standards. To assess the general quality of the timber, stress-wave measurements in combination with resistance drilling and X-ray measurements were applied. The quantitative evaluation of the mechanical properties and the density using stress-wave timing and radiographic measurements provided both good agreement and sufficiently good input for the structural analysis. The accurate use of non-destructive measurements, considering their crucial aspects and limitations, enables reliable results to be obtained, thereby increasing the potential to minimise interventions and prolong the service life of buildings as a part of sustainable development. (C) 2014 Published by Elsevier Ltd.
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| 12. |
- Lechner, Thomas, 1979
(författare)
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In-situ assessment of timber structures - Assessment methods and case studies
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In the assessment of timber structures, diagnostic investigations with reference to the condition and structural performance of these structures are necessary and often require appropriate health monitoring techniques. This thesis covers four aspects within the research area of the in-situ assessment of timber structures based on scientific knowledge and guidelines to perform assessment of existing timber structures:IDetermination of density of wood with portable X-rayThe mechanical performance of timber is often strongly related to the density of wood. This work focused on the development of an in-situ calibration procedure to determine the density using X-ray, thereby enabling the prediction of the mechanical properties of timber as well as to evaluate the internal condition of the structure.IIProperty assessment of oak from the Vasa warshipX-ray density measurements combined with mechanical tests from present and previous studies were used in the evaluation to non-destructively predict the mechanical properties in the proposed methodology for the special case of Vasa oak. IIIIn-situ assessment of historical timber structuresSystematic assessment strategies were applied to assess the mechanical performance and structural health monitoring techniques to preserve historical structures without interfering with their structural integrity and capacity. This is of vital importance to minimise interventions and prolong the service life of timber structures.IVPilot study of the assessment of stresses in loaded structuresA resonance frequency analysis procedure was investigated in this pilot study to evaluate the opportunity to determine the tensile capacity on site for peaks of unexpected increased loads and to detect the most loaded vulnerable members.It has been shown that a systematic assessment strategy is valuable and effective in the evaluation of the structural condition and performance of the structure in order to preserve (historical) timber structures to the greatest extent possible. The combination of structural health monitoring techniques is necessary to achieve accurate results for the analysis of the structural performance and they require further specific development.
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| 13. |
- Lechner, Thomas, 1979, et al.
(författare)
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Strategy for developing a future support system for the Vasa warship and evaluating its mechanical properties
- 2013
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Ingår i: Heritage Science. - : Springer Science and Business Media LLC. - 2050-7445. ; 1:35
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Forskningsöversikt (refereegranskat)abstract
- To maintain the integrity of the Vasa warship after salvage in 1961, conservation treatment with polyethylene glycol was carried out to prevent the collapse of cell walls. This treatment had negative effects on the strength and stiffness of the oak and the hull structure has been found to slowly deform over time. It is of interest to construct a three-dimensional numerical computer model to model and predict the deformation of the warship. This creates difficulties related to the complexity of measuring the detailed material properties that are required as input. In this context, a non-destructive methodology to predict the stiffness of the Vasa oak in terms of moduli of elasticity in the three principal directions of timber at critical positions in the ship would be useful. The twofold aim of the paper is to propose a strategy for a support system and to conduct an on-site assessment of the warship to predict the mechanical properties of the Vasa oak material. This paper also contains an up-to-date review of all essential mechanical data measured on the Vasa oak. The preliminary investigation using an X-ray technique to investigate the density properties produced promising results for future use in the evaluation of the mechanical performance. Based on these results, a procedure to establish the stiffness properties of the Vasa oak in terms of MOE was suggested, using a combination of data from previous measurements, in combination with extended tests on Vasa oak specimens and an X-ray-based density calibration procedure. The general complexity of the Vasa warship can be mainly attributed to large variations in the properties of Vasa oak due to surface degradation, chemical treatment and the disintegration of the cell-wall structure originating from centuries of waterlogged conditions. That causes difficulties when assessing mechanical and physical properties on a structural level. A combination of visual inspection together with X-ray investigation is of great importance to evaluate those properties and to obtain more accurate estimates. The results from evaluating mechanical properties can serve as input in a numerical model and serve as a foundation for decision-making relating to the modification of the support system.
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| 14. |
- Lechner, Thomas, 1979, et al.
(författare)
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Stress level prediction in axially-loaded timber beams using resonance frequency analysis: A pilot study
- 2013
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Ingår i: Advanced Materials Research. - 1662-8985 .- 1022-6680. ; 778, s. 454-461
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Konferensbidrag (refereegranskat)abstract
- The structural integrity due to problems in the uncertainties of load, the load-carrying capacity of timber structures is of great importance, since peaks of increased loads might occur. One solution of these problems lies in the evaluation of timber structures using non-destructive testing (NDT) methods, and in this special case frequency based identification methods.This paper deals with the investigation whether it is possible to estimate the axial loads in timber beams using resonance frequency analysis to evaluate on whether the beams have sufficient load-bearing capacity. This was achieved by performing transversal frequency measurements on 32 timber specimens and an aluminium bar under tension. The latter hereby served as a homogeneous reference for better interpretation of results. The two first frequencies, together with different values for the E-modulus were then used to estimate the axial load S and the rotational stiffness k at the boundaries. The stress levels for the timber ranged from 2 MPa to 11 MPa, whereas for the aluminium reference bar the frequencies were measured for stress levels from 4 MPa to 32 MPa. The numerical model behind the calculations was based on Timoshenko beam theory, including effects of shear deformations and flexural stiffness. Finally, a sensitivity analysis was carried out to investigate the influence of errors in input parameters on the final results.The best results were obtained using the E-modulus derived from transversal vibration tests and showed a mean error ranging from 7.6% to 46.6%, where the results generally improved for higher loads. The results of the sensitivity analysis showed that the sensitivity of the estimated axial load decreases for higher stress levels, which could also be observed in the test results. The most influential parameters on the quality of the results were the measured frequencies and the clear beam length, followed by the density and the E-modulus.
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| 15. |
- Purdue, Mark P, et al.
(författare)
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Genome-wide association study of renal cell carcinoma identifies two susceptibility loci on 2p21 and 11q13.3
- 2011
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 43:1, s. 60-65
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Tidskriftsartikel (refereegranskat)abstract
- We conducted a two-stage genome-wide association study of renal cell carcinoma (RCC) in 3,772 affected individuals (cases) and 8,505 controls of European background from 11 studies and followed up 6 SNPs in 3 replication studies of 2,198 cases and 4,918 controls. Two loci on the regions of 2p21 and 11q13.3 were associated with RCC susceptibility below genome-wide significance. Two correlated variants (r² = 0.99 in controls), rs11894252 (P = 1.8 × 10⁻⁸) and rs7579899 (P = 2.3 × 10⁻⁹), map to EPAS1 on 2p21, which encodes hypoxia-inducible-factor-2 alpha, a transcription factor previously implicated in RCC. The second locus, rs7105934, at 11q13.3, contains no characterized genes (P = 7.8 × 10⁻¹⁴). In addition, we observed a promising association on 12q24.31 for rs4765623, which maps to SCARB1, the scavenger receptor class B, member 1 gene (P = 2.6 × 10⁻⁸). Our study reports previously unidentified genomic regions associated with RCC risk that may lead to new etiological insights.
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| 16. |
- Sawcer, Stephen, et al.
(författare)
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Genetic risk and a primary role for cell-mediated immune mechanisms in multiple sclerosis
- 2011
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 476:7359, s. 214-219
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Tidskriftsartikel (refereegranskat)abstract
- Multiple sclerosis is a common disease of the central nervous system in which the interplay between inflammatory and neurodegenerative processes typically results in intermittent neurological disturbance followed by progressive accumulation of disability. Epidemiological studies have shown that genetic factors are primarily responsible for the substantially increased frequency of the disease seen in the relatives of affected individuals, and systematic attempts to identify linkage in multiplex families have confirmed that variation within the major histocompatibility complex (MHC) exerts the greatest individual effect on risk. Modestly powered genome-wide association studies (GWAS) have enabled more than 20 additional risk loci to be identified and have shown that multiple variants exerting modest individual effects have a key role in disease susceptibility. Most of the genetic architecture underlying susceptibility to the disease remains to be defined and is anticipated to require the analysis of sample sizes that are beyond the numbers currently available to individual research groups. In a collaborative GWAS involving 9,772 cases of European descent collected by 23 research groups working in 15 different countries, we have replicated almost all of the previously suggested associations and identified at least a further 29 novel susceptibility loci. Within the MHC we have refined the identity of the HLA-DRB1 risk alleles and confirmed that variation in the HLA-A gene underlies the independent protective effect attributable to the class I region. Immunologically relevant genes are significantly overrepresented among those mapping close to the identified loci and particularly implicate T-helper-cell differentiation in the pathogenesis of multiple sclerosis.
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| 17. |
- Walker, Anthony P, et al.
(författare)
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Horizon 2020 EuPRAXIA design study
- 2017
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 874:1
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Tidskriftsartikel (refereegranskat)abstract
- The Horizon 2020 Project EuPRAXIA ("European Plasma Research Accelerator with eXcellence In Applications") is preparing a conceptual design report of a highly compact and cost-effective European facility with multi-GeV electron beams using plasma as the acceleration medium. The accelerator facility will be based on a laser and/or a beam driven plasma acceleration approach and will be used for photon science, high-energy physics (HEP) detector tests, and other applications such as compact X-ray sources for medical imaging or material processing. EuPRAXIA started in November 2015 and will deliver the design report in October 2019. EuPRAXIA aims to be included on the ESFRI roadmap in 2020.
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