| 1. |
- Kainu, T, et al.
(författare)
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Somatic deletions in hereditary breast cancers implicate 13q21 as a putative novel breast cancer susceptibility locus
- 2000
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Ingår i: Proceedings of the National Academy of Sciences. - 1091-6490. ; 97:17, s. 9603-9608
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Tidskriftsartikel (refereegranskat)abstract
- A significant proportion of familial breast cancers cannot be explained by mutations in the BRCA1 or BRCA2 genes. We applied a strategy to identify predisposition loci for breast cancer by using mathematical models to identify early somatic genetic deletions in tumor tissues followed by targeted linkage analysis. Comparative genomic hybridization was used to study 61 breast tumors from 37 breast cancer families with no identified BRCA1 or BRCA2 mutations. Branching and phylogenetic tree models predicted that loss of 13q was one of the earliest genetic events in hereditary cancers. In a Swedish family with five breast cancer cases, all analyzed tumors showed distinct 13q deletions, with the minimal region of loss at 13q21-q22. Genotyping revealed segregation of a shared 13q21 germ-line haplotype in the family. Targeted linkage analysis was carried out in a set of 77 Finnish, Icelandic, and Swedish breast cancer families with no detected BRCA1 and BRCA2 mutations. A maximum parametric two-point logarithm of odds score of 2.76 was obtained for a marker at 13q21 (D13S1308, theta = 0.10). The multipoint logarithm of odds score under heterogeneity was 3.46. The results were further evaluated by simulation to assess the probability of obtaining significant evidence in favor of linkage by chance as well as to take into account the possible influence of the BRCA2 locus, located at a recombination fraction of 0.25 from the new locus. The simulation substantiated the evidence of linkage at D13S1308 (P < 0.0017). The results warrant studies of this putative breast cancer predisposition locus in other populations.
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| 2. |
- Moberg, Christina, et al.
(författare)
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De unga gör helt rätt när de stämmer staten
- 2022
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Ingår i: Aftonbladet. - 1103-9000.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- 1 620 forskare och lärare i forskarvärlden: Vi ställer oss bakom Auroras klimatkrav
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| 3. |
- Ny, Henrik, et al.
(författare)
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Systems Dynamic Modeling within Sustainability Constraints
- 2005
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Konferensbidrag (refereegranskat)abstract
- In this study we are asking ourselves whether ■Systems Dynamic Modelling■ can be combined with ■Backcasting from Sustainability Principles■ to support strategic planning towards sustainability. From the perspective of a ■Backcasting Practitioner■, ■Systems Dynamic Modelling■ is a set of tools that help gaining insight into the detailed functioning of a given system, but lacks the ability to support strategic planning towards sustainability ■ unless complemented with a satisfactory goal definition. ■Backcasting from Sustainability Principles■, in the eyes of a ■Systems Modeller■, is the planning step of a learning loop that also includes action implementation and follow-up. Since no dynamic modelling takes place this methodology typically produces laundry lists of isolated problems and solutions, thereby missing potentially important feedback loops, delays, hidden problems and suitable intervention points in the system.
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| 4. |
- Björklund, Verna, et al.
(författare)
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Early-onset group B streptococcal infections in five Nordic countries with different prevention policies, 1995 to 2019
- 2024
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Ingår i: Eurosurveillance. - : European Centre for Disease Control and Prevention (ECDC). - 1025-496X .- 1560-7917. ; 29:3
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Tidskriftsartikel (refereegranskat)abstract
- Background: Neonatal early-onset disease caused by group B Streptococcus (GBS) is a leading cause of infant morbidity. Intrapartum antibiotic prophylaxis (IAP) is effective in preventing early-onset GBS disease, but there is no agreement on the optimal strategy for identifying the pregnant women requiring this treatment, and both risk-based prophylaxis (RBP) and GBS screening-based prophylaxis (SBP) are used.Aim: The aim of this study was to evaluate the effect of SBP as a public health intervention on the epidemiology of early-onset GBS infections.Methods: In 2012, Finland started the universal SBP, while Denmark, Iceland, Norway and Sweden continued with RBP. We conducted an interrupted time series analysis taking 2012 as the intervention point to evaluate the impact of this intervention. The incidences of early- and late-onset GBS infections during Period I (1995-2011) and Period II (2012-2019) were collected from each national register, covering 6,605,564 live births.Results: In Finland, a reduction of 58% in the incidence of early-onset GBS disease, corresponding to an incidence rate ratio (IRR) of 0.42 (95% CI: 0.34-0.52), was observed after 2012. At the same time, the pooled IRR of other Nordic countries was 0.89 (95% CI: 0.80-1.0), specifically 0.89 (95% CI: 0.70-1.5) in Denmark, 0.34 (95% CI: 0.15-0.81) in Iceland, 0.72 (95% CI: 0.59-0.88) in Norway and 0.97 (95% CI: 0.85-1.1) in Sweden.Conclusions: In this ecological study of five Nordic countries, early-onset GBS infections were approximately halved following introduction of the SBP approach as compared with RBP.
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| 5. |
- Ebbers, Tino, et al.
(författare)
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Higher order weighted least-squares phase offset correction for improved accuracy in phase-contrast MRI
- 2008
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Konferensbidrag (refereegranskat)abstract
- Phase-contrast magnetic resonance imaging has the ability to accurately measure blood flow and myocardial velocities in the human body. Unwanted spatially varying phase offsets are, however, always present and may deteriorate the measurements significantly. Some of these phase offsets can be estimated based on the pulse sequence (1), but effects caused by eddy currents are more difficult to predict. A linear fit of the phase values is often estimated from either a number of manually defined areas containing stationary tissue or by semi-automatic detection of stationary tissue using the
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| 6. |
- Ha, Hojin, et al.
(författare)
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Assessment of turbulent viscous stress using ICOSA 4D Flow MRI for prediction of hemodynamic blood damage
- 2016
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Ingår i: SCIENTIFIC REPORTS. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Flow-induced blood damage plays an important role in determining the hemodynamic impact of abnormal blood flow, but quantifying of these effects, which are dominated by shear stresses in highly fluctuating turbulent flow, has not been feasible. This study evaluated the novel application of turbulence tensor measurements using simulated 4D Flow MRI data with six-directional velocity encoding for assessing hemodynamic stresses and corresponding blood damage index (BDI) in stenotic turbulent blood flow. The results showed that 4D Flow MRI underestimates the maximum principal shear stress of laminar viscous stress (PLVS), and overestimates the maximum principal shear stress of Reynolds stress (PRSS) with increasing voxel size. PLVS and PRSS were also overestimated by about 1.2 and 4.6 times at medium signal to noise ratio (SNR) = 20. In contrast, the square sum of the turbulent viscous shear stress (TVSS), which is used for blood damage index (BDI) estimation, was not severely affected by SNR and voxel size. The square sum of TVSS and the BDI at SNR amp;gt;20 were underestimated by less than 1% and 10%, respectively. In conclusion, this study demonstrated the feasibility of 4D Flow MRI based quantification of TVSS and BDI which are closely linked to blood damage.
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| 7. |
- Haraldsson, Henrik, 1977-
(författare)
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Assessment of Myocardial Function using Phase Based Motion Sensitive MRI
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Quantitative assessment of myocardial function is a valuable tool for clinical applications and physiological studies. This assessment can be acquired using phase based motion sensitive magnetic resonance imaging (MRI) techniques. In this thesis, the accuracy of these phase based motion sensitive MRI techniques is investigated, and modifications in acquisition and post-processing are proposed.The strain rate of the myocardium can be used to evaluate the myocardial function. However, the estimation of strain rate from the velocity data acquired with phase-contrast MRI (PC-MRI) is sensitive to noise. Estimation using normalized convolution showed, however, to reduce this sensitivity to noise and to minimize the influence of non-myocardial tissue which could impair the result.Strain of the myocardium is another measure to assess myocardial function. Strain can be estimated from the myocardial displacement acquired with displacement encoding with stimulated echo (DENSE). DENSE acquisition can be realized with several different encoding strategies. The choice of encoding scheme may make the acquisition more or less sensitive to different sources of error. Two potential sources of errors in DENSE acquisition are the influence of the FID and of the off-resonance effects. Their influence on DENSE were investigated to determine suitable encoding strategies to reduce their influence and thereby improve the measurement accuracy acquired.The quality of the DENSE measurement is not only dependent on the accuracy, but also the precision of the measurement. The precision is affected by the SNR and thereby depends on flip angle strategies, magnetic field strength and spatial variation of the receiver coil sensitivity. A mutual comparison of their influence on SNR in DENSE was therefore performed and could serve as a guideline to optimize parameters for specific applications.The acquisition time is often an important factor, especially in clinical applications where it affects potential patient discomfort and patient through-put. A multiple-slice DENSE acquisition was therefore presented, which allows the acquisition of strain values according to the 16-segment cardiac model within a single breath-hold, instead of the conventional three breath-holds.The DENSE technique can also be adapted toward comprehensive evaluation of the heart in the form of full three-dimensional three-directional acquisition of the displacement. To estimate the full strain tensor from these data, a novel post-processing technique using a polynomial was investigated. The method yielded accurate results on an analytical model and \textit{in-vivo} strains obtained agreed with previously reported myocardial strains in normal volunteers.
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| 8. |
- Haraldsson, Henrik, et al.
(författare)
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Assessment of Reynolds stress components and turbulent pressure loss using 4D flow MRI with extended motion encoding
- 2018
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Ingår i: Magnetic Resonance in Medicine. - : WILEY. - 0740-3194 .- 1522-2594. ; 79:4, s. 1962-1971
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Tidskriftsartikel (refereegranskat)abstract
- PurposeTo measure the Reynolds stress tensor using 4D flow MRI, and to evaluate its contribution to computed pressure maps. MethodsA method to assess both velocity and Reynolds stress using 4D flow MRI is presented and evaluated. The Reynolds stress is compared by cross-sectional integrals of the Reynolds stress invariants. Pressure maps are computed using the pressure Poisson equationboth including and neglecting the Reynolds stress. ResultGood agreement is seen for Reynolds stress between computational fluid dynamics, simulated MRI, and MRI experiment. The Reynolds stress can significantly influence the computed pressure loss for simulated (eg, -0.52% vs -15.34% error; Pamp;lt;0.001) and experimental (eg, 30611 vs 203 +/- 6 Pa; Pamp;lt;0.001) data. A 54% greater pressure loss is seen at the highest experimental flow rate when accounting for Reynolds stress (Pamp;lt;0.001). Conclusion4D flow MRI with extended motion-encoding enables quantification of both the velocity and the Reynolds stress tensor. The additional information provided by this method improves the assessment of pressure gradients across a stenosis in the presence of turbulence. Unlike conventional methods, which are only valid if the flow is laminar, the proposed method is valid for both laminar and disturbed flow, a common presentation in diseased vessels. Magn Reson Med 79:1962-1971, 2018. (c) 2017 International Society for Magnetic Resonance in Medicine.
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| 9. |
- Haraldsson, Henrik, et al.
(författare)
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Comparison of DENSE Reference Strategies
- 2009
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Ingår i: Proceedings of the International Society for Magnetic Resonance in Medicine. ; , s. 819-819
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Konferensbidrag (refereegranskat)
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| 10. |
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