| 1. |
- Berndt, Sonja, I, et al.
(author)
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Distinct germline genetic susceptibility profiles identified for common non-Hodgkin lymphoma subtypes
- 2022
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In: Leukemia. - : Springer Nature. - 0887-6924 .- 1476-5551. ; 36:12, s. 2835-2844
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Journal article (peer-reviewed)abstract
- Lymphoma risk is elevated for relatives with common non-Hodgkin lymphoma (NHL) subtypes, suggesting shared genetic susceptibility across subtypes. To evaluate the extent of mutual heritability among NHL subtypes and discover novel loci shared among subtypes, we analyzed data from eight genome-wide association studies within the InterLymph Consortium, including 10,629 cases and 9505 controls. We utilized Association analysis based on SubSETs (ASSET) to discover loci for subsets of NHL subtypes and evaluated shared heritability across the genome using Genome-wide Complex Trait Analysis (GCTA) and polygenic risk scores. We discovered 17 genome-wide significant loci (P < 5 × 10−8) for subsets of NHL subtypes, including a novel locus at 10q23.33 (HHEX) (P = 3.27 × 10−9). Most subset associations were driven primarily by only one subtype. Genome-wide genetic correlations between pairs of subtypes varied broadly from 0.20 to 0.86, suggesting substantial heterogeneity in the extent of shared heritability among subtypes. Polygenic risk score analyses of established loci for different lymphoid malignancies identified strong associations with some NHL subtypes (P < 5 × 10−8), but weak or null associations with others. Although our analyses suggest partially shared heritability and biological pathways, they reveal substantial heterogeneity among NHL subtypes with each having its own distinct germline genetic architecture.
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| 2. |
- Sampson, Joshua N., et al.
(author)
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Analysis of Heritability and Shared Heritability Based on Genome-Wide Association Studies for 13 Cancer Types
- 2015
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In: Journal of the National Cancer Institute. - : Oxford University Press (OUP). - 0027-8874 .- 1460-2105. ; 107:12
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Journal article (peer-reviewed)abstract
- Background: Studies of related individuals have consistently demonstrated notable familial aggregation of cancer. We aim to estimate the heritability and genetic correlation attributable to the additive effects of common single-nucleotide polymorphisms (SNPs) for cancer at 13 anatomical sites. Methods: Between 2007 and 2014, the US National Cancer Institute has generated data from genome-wide association studies (GWAS) for 49 492 cancer case patients and 34 131 control patients. We apply novel mixed model methodology (GCTA) to this GWAS data to estimate the heritability of individual cancers, as well as the proportion of heritability attributable to cigarette smoking in smoking-related cancers, and the genetic correlation between pairs of cancers. Results: GWAS heritability was statistically significant at nearly all sites, with the estimates of array-based heritability, h(l)(2), on the liability threshold (LT) scale ranging from 0.05 to 0.38. Estimating the combined heritability of multiple smoking characteristics, we calculate that at least 24% (95% confidence interval [CI] = 14% to 37%) and 7% (95% CI = 4% to 11%) of the heritability for lung and bladder cancer, respectively, can be attributed to genetic determinants of smoking. Most pairs of cancers studied did not show evidence of strong genetic correlation. We found only four pairs of cancers with marginally statistically significant correlations, specifically kidney and testes (rho = 0.73, SE = 0.28), diffuse large B-cell lymphoma (DLBCL) and pediatric osteosarcoma (rho = 0.53, SE = 0.21), DLBCL and chronic lymphocytic leukemia (CLL) (rho = 0.51, SE = 0.18), and bladder and lung (rho = 0.35, SE = 0.14). Correlation analysis also indicates that the genetic architecture of lung cancer differs between a smoking population of European ancestry and a nonsmoking Asian population, allowing for the possibility that the genetic etiology for the same disease can vary by population and environmental exposures. Conclusion: Our results provide important insights into the genetic architecture of cancers and suggest new avenues for investigation.
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| 3. |
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| 4. |
- Wang, Zhaoming, et al.
(author)
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Imputation and subset-based association analysis across different cancer types identifies multiple independent risk loci in the TERT-CLPTM1L region on chromosome 5p15.33
- 2014
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In: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 23:24, s. 6616-6633
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Journal article (peer-reviewed)abstract
- Genome-wide association studies (GWAS) have mapped risk alleles for at least 10 distinct cancers to a small region of 63 000 bp on chromosome 5p15.33. This region harbors the TERT and CLPTM1L genes; the former encodes the catalytic subunit of telomerase reverse transcriptase and the latter may play a role in apoptosis. To investigate further the genetic architecture of common susceptibility alleles in this region, we conducted an agnostic subset-based meta-analysis (association analysis based on subsets) across six distinct cancers in 34 248 cases and 45 036 controls. Based on sequential conditional analysis, we identified as many as six independent risk loci marked by common single-nucleotide polymorphisms: five in the TERT gene (Region 1: rs7726159, P = 2.10 × 10(-39); Region 3: rs2853677, P = 3.30 × 10(-36) and PConditional = 2.36 × 10(-8); Region 4: rs2736098, P = 3.87 × 10(-12) and PConditional = 5.19 × 10(-6), Region 5: rs13172201, P = 0.041 and PConditional = 2.04 × 10(-6); and Region 6: rs10069690, P = 7.49 × 10(-15) and PConditional = 5.35 × 10(-7)) and one in the neighboring CLPTM1L gene (Region 2: rs451360; P = 1.90 × 10(-18) and PConditional = 7.06 × 10(-16)). Between three and five cancers mapped to each independent locus with both risk-enhancing and protective effects. Allele-specific effects on DNA methylation were seen for a subset of risk loci, indicating that methylation and subsequent effects on gene expression may contribute to the biology of risk variants on 5p15.33. Our results provide strong support for extensive pleiotropy across this region of 5p15.33, to an extent not previously observed in other cancer susceptibility loci.
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| 5. |
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| 6. |
- Ahrné, Karin, et al.
(author)
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Dagfjärilar i naturbetesmarker, kraftledningsgator, på hyggen och skogsbilvägar : betydelse för miljöövervakning
- 2011
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Reports (other academic/artistic)abstract
- Ett förändrat och intensifierat jordbruk har bland annat lett till att naturbetesmarker och andra gräsmarksbiotoper minskat i odlingslandskapet. Detta har fått till följd att många arter knutna till öppna gräsmarker minskat, däribland fåglar, växter och dagfjärilar. Dagfjärilar svarar snabbt på förändringar både i miljön och klimatet och kan därför vara viktiga indikatorarter för miljöövervakning. I år startar en nationell övervakning av dagfjärilar med hjälp av volontärer och de senaste fem åren har dagfjärilar inventerats i ängs- och betesmarker inom den nationella inventeringen av landskapet (NILS). För att få en rättvisande bild av hur situationen ser ut för dagfjärilar i Sverige kan det vara viktigt att systematiskt inventera olika typer av miljöer, inte enbart ängs- och betesmarker eller känt artrika platser. I den här studien jämför vi artrikedom, individantal och artsammansättning av dagfjärilar (Rophalocera) och bastardsvärmare (Zyganidaea) i naturbetesmarker och tre typer av öppna biotoper i skogslandskapet; hyggen, kraftledningsgator och skogsbilvägar. Vi delar också in fjärilarna efter val av värdväxt och flygtid på säsongen för att se om det finns några skillnader mellan biotoperna vad gäller art- och individrikedom inom dessa grupper. Vi undersöker hur mängden skog och betesmark inom det omgivande landskapet påverkar dagfjärilsfaunan på de olika platserna och hur många inventeringstillfällen (3, 5 eller 7) som krävs för att få tillförlitliga data på artrikedomen på en plats. Våra resultat visar att artsammansättningen av fjärilar skiljer sig mellan biotoperna och att alla bidrar med unika arter och således kompletterar varandra. Kraftledningsgatorhade både fler fjärilsarter och individer än de övriga biotoperna och hyggen och skogsbilvägar var lika art- och individrika som betesmarkerna. Det är därför viktigt att övervaka flera typer av miljöer och även skogsbiotoper inom framtida dagfjärilsövervakning. Eftersom alla tre skogsbiotoperna hyser en stor mångfald av fjärilar kan det vara värt att anpassa skötseln av dessa miljöer för att gynna fjärilar. I kraftledningsgator och skogsbilvägar som är relativt beständiga miljöer och som redan idag sköts med ett visst intervall är detta fullt möjligt. Betydelsen av antal inventeringstillfällen beror på vilken frågeställning man har. Vill man jämföra artrikedomen i olika miljöer eller studera förändring i artrikedom mellan år kan det kanske räcka med tre besök, men vill man ha en mer heltäckande bild av artrikedomen på en plats kan det sju eller fler besök spridda över säsongen
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| 7. |
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| 8. |
- Alkner, Sara, et al.
(author)
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Quality assessment of radiotherapy in the prospective randomized SENOMAC trial
- 2024
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In: Radiotherapy and Oncology. - 0167-8140 .- 1879-0887. ; 197
-
Journal article (peer-reviewed)abstract
- Background and purpose: Recommendations for regional radiotherapy (RT) of sentinel lymph node (SLN)-positive breast cancer are debated. We here report a RT quality assessment of the SENOMAC trial.Materials and Methods: The SENOMAC trial randomized clinically node-negative breast cancer patients with 1–2 SLN macrometastases to completion axillary lymph node dissection (cALND) or SLN biopsy only between 2015–2021. Adjuvant RT followed national guidelines. RT plans for patients included in Sweden and Denmark until June 2019 were collected (N = 1176) and compared to case report forms (CRF). Dose to level I (N = 270) and the humeral head (N = 321) was analyzed in detail.Results: CRF-data and RT plans agreed in 99.3 % (breast/chest wall) and in 96.6 % of patients (regional RT). Congruence for whether level I was an intended RT target was lower (78 %). In accordance with Danish national guidelines, level I was more often an intended target in the SLN biopsy only arm (N = 334/611, 55 %,) than in the cALND arm (N = 174/565, 31 %,). When an intended target, level I received prescribed dose to 100 % (IQR 98–100 %) of the volume. However, even when not an intended target, full dose was delivered to > 80 % of level I (IQR 75–90 %). The intentional inclusion of level I in the target volume more than doubled the dose received by ≥ 50 % of the humeral head.Conclusion: Congruence between CRF data and RT plans was excellent. Level I received a high dose coverage even when not intentionally included in the target. Including level I in target significantly increased dose to the humeral head.
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| 9. |
- Andersson-Engels, Stefan, et al.
(author)
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Effects of Optical-constants On Time-gated Transillumination of Tissue and Tissue-like Media
- 1992
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In: Journal of Photochemistry and Photobiology, B: Biology. - 1011-1344. ; 16:2, s. 155-167
-
Journal article (peer-reviewed)abstract
- Light transillumination was used to study structures inside turbid media. Time-gated viewing was performed to suppress multiply-scattered light and thus improve spatial resolution. We demonstrate that, for the case of scattering-dominated attenuation (scattering coefficient much greater than the absorption coefficient), the detection of early transmitted light will be practically insensitive to variations in the absorption coefficient. This is an important observation for the development of time-gated optical mammography, since optical mammography using continuous-wave light is based on increased light absorption in the tumour region caused by the neovascularization surrounding a tumour. In order to detect tumours in time-gated viewing it is the scattering coefficient of the tumour that must be characteristic. The scattering coefficient is measured to be lower in the tumour region than in the surrounding breast tissue for one resected breast specimen.
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| 10. |
- Andersson-Engels, Stefan, et al.
(author)
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Laser Spectroscopy in Medical Diagnostics
- 1992
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In: Photodynamic Therapy: Basic Principles and Clinical Applications. - 0824786807 ; , s. 387-424
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Book chapter (peer-reviewed)
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| 11. |
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| 12. |
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| 13. |
- Berg, Annika, 1973-
(author)
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Den gränslösa hälsan : Signe och Axel Höjer, folkhälsan och expertisen
- 2009
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Doctoral thesis (other academic/artistic)abstract
- This dissertation investigates the mutual life project of Signe (1896-1988) and Axel Höjer (1890-1974), a married couple who were key actors in the construction of the Swedish welfare state. It emphasises the ways in which they went about asserting a special public health expertise in different contexts. As starting points I take the malleability of the concept folkhälsa (people’s health or population health) and the centrality of expertise in the governance of modern societies. Theoretical concepts such as gender, policy transfer, biopower and governmentality are central to the analysis. The dissertation includes three parts. The first part investigates how the Höjers agreed to coordinate their work and how they, with reference to ideas picked up in France and England at the end of World War I, attempted to reform mother and child health care in Sweden. Their strategies where rhetorical but also practical, using Hagalund outside Stockholm as their experimental ground. The second part investigates, firstly, how Axel Höjer, as General-Director of the Medical Board of Sweden (1935-52) asserted a sociomedical expertise, integrating the emerging social sciences and universalist views on the organisation of the welfare state into the realm of medicine, in order to launch ideas of a thorough reorganisation and expansion of the Swedish health care system. His focus was on preventive medicine and health care, with the complete physical, mental and social health of the whole population as an explicit goal. Secondly, it explores how Signe Höjer at the same time tried to launch ideas on health and wellbeing as a social politician and a public committee member. She also tried to define family policy as a specific policy area. However, despite her training as a nurse and a social worker, she was largely confined to asserting a particularly ”female” expertise, which made her position rather ambiguous in terms of authority. The third part investigates how the Höjers, in the 1950s and 60s, worked with international health, Axel mainly for the WHO in India and Ghana, Signe as a policy entrepreneur, primarily in the fields of childcare and family planning. My findings partly confirm theories that see development aid as an extension of domestic social policy, but they challenge the view of aid as a simple one-way process. I demonstrate how the Höjers at least tried to adapt their projects abroad to meet local circumstances, and also show how they brought lessons from the third world to a domestic public. In the latter case they did not primarily act as experts of Swedish-style social policy, but as experts on the developing countries and on development aid.
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| 14. |
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| 15. |
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| 16. |
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| 17. |
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| 18. |
- Berg, Åke, et al.
(author)
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Butterflies in semi-natural pastures and power-line corridors - effects of flower richness, management, and structural vegetation characteristics
- 2013
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In: Insect Conservation and Diversity. - : Wiley. - 1752-458X .- 1752-4598. ; 6, s. 639-657
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Journal article (peer-reviewed)abstract
- The aim of this study was to compare the butterfly assemblages in semi-natural pastures and power-line corridors and to analyse the effects of vegetation height, occurrence of trees and shrubs and different flowering vascular plant groups on butterfly diversity and abundance. Twelve of 26 analysed butterfly species were more abundant in power-line corridors than in semi-natural pastures. Only one species preferred semi-natural pastures. In semi-natural pastures butterflies were most common in segments with tall vegetation, whereas butterflies in power-line corridors were most common in segments with vegetation of short or intermediate height. Short vegetation was sparser in power-line corridors (mean cover 4%) than in semi-natural pastures (33%), whereas tall vegetation was more common in power-line corridors (59%) than in semi-natural pastures (35%). The amount of flowers was the factor that affected the abundance of most species. Twenty-one of the 26 species showed positive associations with numbers of flowers of different families. Flowers of the plant families Apiaceae, Caryophyllaceae, Primulaceae, Rubiaceae, Scrophulariaceae, and Violaceae showed positive associations with the abundance of several butterfly species. Vegetation height seems to be a limiting factor in semi-natural pastures, and less intensive management (division of pastures into grazing pens, late season grazing, grazing every second year, or reduced grazing pressure) would benefit butterflies. In power-line corridors (dominated by tall vegetation) the opposite would be beneficial for butterflies, for example more frequent clearing of vegetation along the power-line trails combined with mowing of selected areas.
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| 19. |
- Berg, Åke, et al.
(author)
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Butterfly distribution and abundance is affected by variation in the Swedish forest-farmland landscape
- 2011
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In: Biological Conservation. - : Elsevier BV. - 0006-3207 .- 1873-2917. ; 144, s. 2819-2831
-
Journal article (peer-reviewed)abstract
- Remaining patches of semi-natural grasslands are hot spots for biodiversity in modern agricultural landscapes. In Sweden semi-natural pastures cover approximately 500,000 ha. However, power-line corridors, road verges and clear-cuts cover larger areas (in total about 2,000,000 ha), and these open, less intensively managed habitats are potentially important for species associated with taller vegetation and flower resources (e.g. pollinating insects). The aim of the present study was to evaluate the relative importance of semi-natural pastures and the other three open habitats for butterflies in 12 forest-farmland mosaic landscapes in south central Sweden. Species composition differed significantly between habitats in multivariate analyses. Power-line corridors and semi-natural pastures harbored several species that were disproportionally abundant in these habitats (13 and 8 species, respectively), and power-line corridors also harbored several species that were classified as typical in indicator species analyses. There were more butterfly species, higher abundances and a tendency for more individuals of red-listed species in power-line corridors than in the other three habitats. Effects of the surrounding landscape composition seemed to be weaker than that of the local habitat. However, species composition was significantly associated with landscape composition and species with intermediate and low mobility were more abundant in forested landscapes than in landscapes dominated by arable fields. Analyses of flying time and host plants for larvae suggest that early flying species and species associated with dwarf shrubs were more common in power-line corridors than in the other habitats. A landscape perspective, which takes several habitats into account, is needed for conservation of butterfly communities in forest-farmland landscapes. Power-line corridors and road verges offer possibilities for creating habitats that are suitable for pollinating insects through conservation-oriented management. (C) 2011 Elsevier Ltd. All rights reserved.
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| 20. |
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| 21. |
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| 22. |
- Burgelman, Nico, et al.
(author)
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Influence of wheel-rail contact modelling on vehicle dynamic simulation
- 2015
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In: Vehicle System Dynamics. - : Informa UK Limited. - 0042-3114 .- 1744-5159. ; 53:8, s. 1190-1203
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Journal article (peer-reviewed)abstract
- This paper presents a comparison of four models of rolling contact used for online contact force evaluation in rail vehicle dynamics. Until now only a few wheel-rail contact models have been used for online simulation in multibody software (MBS). Many more models exist and their behaviour has been studied offline, but a comparative study of the mutual influence between the calculation of the creep forces and the simulated vehicle dynamics seems to be missing. Such a comparison would help researchers with the assessment of accuracy and calculation time. The contact methods investigated in this paper are FASTSIM, Linder, Kik-Piotrowski and Stripes. They are compared through a coupling between an MBS for the vehicle simulation and Matlab for the contact models. This way the influence of the creep force calculation on the vehicle simulation is investigated. More specifically this study focuses on the influence of the contact model on the simulation of the hunting motion and on the curving behaviour.
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| 23. |
- Casanueva, Carlos, 1981-, et al.
(author)
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Comparison of wear prediction models for different contact conditions
- 2016
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In: Proceedings of the 24th Symposium of the International Association for Vehicle System Dynamics (IAVSD 2015), Graz, Austria, 17-21 August 2015. - : CRC Press. - 9781138028852 - 9781498777025 ; , s. 871-878
-
Conference paper (peer-reviewed)abstract
- Simulation of wheel and rail wear allows to predict long term profile evolution and thus, study the consequences of wheel damage in the dynamic behaviour of the vehicle, or study future maintenance requirements. Several models have been developed which try to solve the wear issue by relating the energy dissipated in the wheel-rail contact to the worn out material, from which two can be highlighted (Tg/A and Archard) which have significant differences on contact level. Even though, the prediction of long term wheel profile evolution has been validated with these two models, which means that for regular applications they seem to have an equivalent behaviour. In this work similarities and differences between the long term wear prediction methodologies are analysed, discussing their actual limitations. Then, these differences are exploited in specific operational cases to compare their wear prediction performance.
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| 24. |
- Casanueva, Carlos, 1981-, et al.
(author)
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On integrated wheel and track damage prediction using vehicle-track dynamic simulations
- 2017
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In: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit. - : Sage Publications. - 0954-4097 .- 2041-3017. ; 231:7, s. 775-785
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Journal article (peer-reviewed)abstract
- The renewal costs for wheels and rails are a substantial part of the costs for rolling stock operators and infrastructure managers all over the world. The causes for reprofiling or grinding are, in most cases, related to the following: (1) wheel or rail profiles with unacceptable wear, (2) appearance of rolling contact fatigue cracks in the surface, and (3) wheel flats caused by locking wheels during braking. The first two causes are related to the dynamic behavior of the vehicle-track system, and can be predicted using multibody simulations. However, there are several limitations that restrain the usefulness of these prediction techniques, such as simulation time constraints, necessary simplifications, and lack of experimental data that lead to educated assumptions. In this paper, we take the end-user perspective in order to show whether the latest developments in wheel-rail damage prediction can be integrated in a simplified framework, and subsequently used by the different stakeholders for an improved management of the different assets involved in the operation of rail vehicles.
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| 25. |
- de Vrind, V. A. J., et al.
(author)
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Effects of GABA and Leptin Receptor-Expressing Neurons in the Lateral Hypothalamus on Feeding, Locomotion, and Thermogenesis
- 2019
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In: Obesity. - : Wiley. - 1930-7381 .- 1930-739X. ; 27:7, s. 1123-1132
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Journal article (peer-reviewed)abstract
- Objective: The lateral hypothalamus (LH) is known for its role in feeding, and it also regulates other aspects of energy homeostasis. How genetically defined LH neuronal subpopulations mediate LH effects on energy homeostasis remains poorly understood. The behavioral effects of chemogenetically activating LH gamma-aminobutyric acid (GABA) and the more selective population of LH GABA neurons that coexpress the leptin receptor (LepR) were compared. Methods: LepR-cre and VGAT-cre mice were injected with AAV5-hSyn-DIO-hM3DGq-mCherry in the LH. The behavioral effects of LH GABA or LH LepR neuronal activation on feeding, locomotion, thermogenesis, and body weight were assessed. Results: The activation of LH GABA neurons increased body temperature (P ≤ 0.008) and decreased body weight (P ≤ 0.01) despite decreased locomotor activity (P = 0.03) and transiently increased chow intake (P ≤ 0.009). Also, similar to other studies, this study found that activation of LH GABA neurons induced gnawing on both food and nonfood (P = 0.001) items. Activation of LH LepR neurons decreased body weight (P ≤ 0.01) and chow intake when presented on the cage floor (P ≤ 0.04) but not when presented in the cage top and increased locomotor activity (P = 0.002) and body temperature (P = 0.03). Conclusions: LH LepR neurons are a subset of LH GABA neurons, and LH LepR activation more specifically regulates energy homeostasis to promote a negative energy balance. © 2019 The Authors. Obesity published by Wiley Periodicals, Inc. on behalf of The Obesity Society (TOS)
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| 26. |
- de Vrind, V. A. J., et al.
(author)
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Leptin Receptor Expressing Neurons in the Substantia Nigra Regulate Locomotion, and in The Ventral Tegmental Area Motivation and Feeding
- 2021
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In: Frontiers in Endocrinology. - : Frontiers Media SA. - 1664-2392. ; 12
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Journal article (peer-reviewed)abstract
- Leptin is an anorexigenic hormone, important in the regulation of body weight. Leptin plays a role in food reward, feeding, locomotion and anxiety. Leptin receptors (LepR) are expressed in many brain areas, including the midbrain. In most studies that target the midbrain, either all LepR neurons of the midbrain or those of the ventral tegmental area (VTA) were targeted, but the role of substantia nigra (SN) LepR neurons has not been investigated. These studies have reported contradicting results regarding motivational behavior for food reward, feeding and locomotion. Since not all midbrain LepR mediated behaviors can be explained by LepR neurons in the VTA alone, we hypothesized that SN LepR neurons may provide further insight. We first characterized SN LepR and VTA LepR expression, which revealed LepR expression mainly on DA neurons. To further understand the role of midbrain LepR neurons in body weight regulation, we chemogenetically activated VTA LepR or SN LepR neurons in LepR-cre mice and tested for motivational behavior, feeding and locomotion. Activation of VTA LepR neurons in food restricted mice decreased motivation for food reward (p=0.032) and food intake (p=0.020), but not locomotion. In contrast, activation of SN LepR neurons in food restricted mice decreased locomotion (p=0.025), but not motivation for food reward or food intake. Our results provide evidence that VTA LepR and SN LepR neurons serve different functions, i.e. activation of VTA LepR neurons modulated motivation for food reward and feeding, while SN LepR neurons modulated locomotor activity.
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| 27. |
- Deutsch, Clemens, 1989-
(author)
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On the Performance of Long-Range Autonomous Underwater Vehicles : Enhancing the Endurance of AUVs
- 2022
-
Doctoral thesis (other academic/artistic)abstract
- Autonomous underwater vehicles (AUVs) are robotic platforms that are commonly used to gather environmental data, provide bathymetric images, and perform manipulation tasks. These robots are used not only for scientific, but also for industrial and military purposes. Climate change, political instabilities, and the increasing demand for both renewable and fossil energy sources have created a need for high-performance AUVs and particularly long-range AUVs.The performance of long-range AUVs is characterised by several parameters, such as autonomous decision making, accurate navigation, system reliability, and vehicle endurance. The vehicle’s endurance is the key capability enabling long-range missions and is determined by the energy capacity and power consumption. By cruising at optimum speed, the vehicle endurance can be utilised most efficiently, resulting in the longest achievable vehicle range. The range of AUVs can be extended by maximising the available energy capacity and by minimising the overall power consumption. This thesis shows how the choices of propulsion system and power source can help improving the range of AUVs.The power consumption comprises the hotel load and propulsive power. While the hotel load is largely depending on the payload sensors, the propulsive power can be minimised by choosing the right propulsion system. As a part of this thesis, the transit performance of underwater gliders is analysed using an analytical approach. The analysis yields a glide metric for the assessment of the energy efficiency of underwater gliding and allows for comparison to other conventional propulsion systems.The most common energy systems for AUVs are primary and secondary electrochemical cells, in particular lithium-ion batteries. Alternative energy systems such as fuel cell (FC) systems can potentially improve the range of AUVs. Through a conceptual design study using off-the-shelf components, it is shown how FC systems can increase the energy capacity of AUVs. FC systems are typically implemented as hybrid systems paired with a small capacity battery system. Energy management strategies (EMS) are required to coordinate these two power sources. In this thesis, deterministic and optimisation-based strategies have been tested in simulations and evaluated against realistic AUV power consumption data from field trials. The results suggest that the complexity of the EMS needs to grow with mission complexity. While deterministic methods can yield the lowest energy consumption for standard missions (e.g. bathymetric imaging), optimisation-based methods provide best load-following behavior, making these methods better suited for retaining power reliability through maintaining battery state of charge.
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| 28. |
- Dirks, Babette, et al.
(author)
-
Prediction of wheel profile wear and crack growth : Comparisons with measurements
- 2015
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In: CM 2015 - 10th International Conference on Contact Mechanics of Wheel / Rail Systems.
-
Conference paper (peer-reviewed)abstract
- A model which can predict the surface crack length and crack depth in rails was developed in a previous study by the authors1. In the present study, this crack prediction model in combination with a wear prediction model is verified against wheel measurements. For a period of 15 months, the wheels of three units of a Stockholm commuter train were measured with respect to wear and crack development. Vehicle-track dynamics simulations were used to calculate the forces and contact positions for the wear and crack prediction models. It can be concluded that the wear prediction model gives reasonable results, especially considering the large scatter in the wheel profile measurements. Although the crack prediction model had to be adjusted for the current wheel application, the results appear promising.
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| 29. |
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| 30. |
- Dirks, Babette, et al.
(author)
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Prediction of wheel profile wear and crack growth - comparisons with measurements
- 2016
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In: Wear. - : Elsevier. - 0043-1648 .- 1873-2577. ; 366, s. 84-94
-
Journal article (peer-reviewed)abstract
- A model which can predict the length of the surface crack and crack depth in rails was developed in a previous study by the authors B. Dirks, R. Enblom, A. Ekberg, M. Berg (2015) []. In the present study, verification of this crack prediction model in combination with a wear prediction model was done against wheel measurements. For a period of 15 months, the wheels of three units of a Stockholm commuter train were measured with respect to wear and crack development for verification of the wheel life prediction tool. Vehicle-track dynamics simulations were used to calculate the forces and contact positions for the wear and crack prediction models. It can be concluded that the wear prediction model gives reasonable results, especially considering the large scatter in the wheel profile measurements. Although the wheel life prediction tool could not be verified, since the crack prediction model had to be recalibrated for the current wheel application, the results appear promising.
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| 31. |
- Dirks, Babette, 1976-
(author)
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Simulation and Measurement of Wheel on Rail Fatigue and Wear
- 2015
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Doctoral thesis (other academic/artistic)abstract
- The life of railway wheels and rails has been decreasing in recent years. This is mainly caused by more traffic and running at higher vehicle speed. A higher speed usually generates higher forces, unless compensated by improved track and vehicle designs, in the wheel-rail contact, resulting in more wear and rolling contact fatigue (RCF) damage to the wheels and rails. As recently as 15 years ago, RCF was not recognised as a serious problem. Nowadays it is a serious problem in many countries and ''artificial wear'' is being used to control the growth of cracks by preventive re-profiling and grinding of, respectively, the wheels and rails. This can be used because a competition exists between wear and surface initiated RCF: At a high wear rate, RCF does not have the opportunity to develop further. Initiated cracks are in this case worn off and will not be able to propagate deep beneath the surface of the rail or wheel.When wheel-rail damage in terms of wear and RCF can be predicted, measures can be taken to decrease it. For example, the combination of wheel and rail profiles, or the combination of vehicle and track, can be optimised to control the damage. Not only can this lead to lower maintenance costs, but also to a safer system since high potential risks can be detected in advance.This thesis describes the development of a wheel-rail life prediction tool with regard to both wear and surface-initiated RCF. The main goal of this PhD work was to develop such a tool where vehicle-track dynamics simulations are implemented. This way, many different wheel-rail contact conditions which a wheel or a rail will encounter in reality can be taken into account.The wear prediction part of the tool had already been successfully developed by others to be used in combination with multibody simulations. The crack prediction part, however, was more difficult to be used in combination with multibody simulations since crack propagation models are time-consuming. Therefore, more concessions had to be made in the crack propagation part of the tool, since time-consuming detailed modelling of the crack, for example in Finite Elements models, was not an option. The use of simple and fast, but less accurate, crack propagation models is the first step in the development of a wheel-rail life prediction model.Another goal of this work was to verify the wheel-rail prediction tool against measurements of profile and crack development. For this purpose, the wheel profiles of trains running on the Stockholm commuter network have been measured together with the crack development on these wheels. Three train units were selected and their wheels have been measured over a period of more than a year. The maximum running distance for these wheels was 230,000 km.A chosen fatigue model was calibrated against crack and wear measurements of rails to determine two unknown parameters. The verification of the prediction tool against the wheel measurements, however, showed that one of the calibrated parameters was not valid to predict RCF on wheels. It could be concluded that wheels experience relatively less RCF damage than rails. Once the two parameters were calibrated against the wheel measurements, the prediction tool showed promising results for predicting both wear and RCF and their trade-off. The predicted position of the damage on the tread of the wheel also agreed well with the position found in the measurements.
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| 32. |
- Dirks, Babette, et al.
(author)
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The development of a crack propagation model for railway wheels and rails
- 2015
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In: Fatigue and Fracture of Engineering Materials and Structures. - : Wiley. - 8756-758X .- 1460-2695. ; 38:12, s. 1478-1491
-
Journal article (peer-reviewed)abstract
- Rolling contact fatigue (RCF) and wear of railway wheels and rails are the main phenom-ena that affect their m aintenance costs. When crack propagation and wear rates can bepredicted, maintenance planning can be optimised, and cost-effective measures can bedeveloped. Several RCF models exist, but none which can be used in combination withvehicle dynamics simulations and can predict the actual crack depth. This study showsthe development of a crack propagation model that can be applied for both railwaywheels and rails. Two unknow n material parameters in the model were calibrated againstcrack measurements in a curve on the Dutch railways over a period of 5 years. Two dif-ferent RCF models were used to calculate the stress magnitudes for the propagationmodel. The propagation model can be used in combination with vehicle-track dynamicssimulations and shows promise in predicting the actual crack depth and/or surface length.Further research is needed to determine the model’s validity for other operationalconditions.
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| 33. |
- Einarsdottir, Sif, et al.
(author)
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Career Education in the Nordic Countries: A Comparison of National Legislation and Compulsory School Curricula
- 2023
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In: Nordic Journal of Transitions, Careers and Guidance. - 2003-8046. ; 4:1, s. 97-112
-
Journal article (peer-reviewed)abstract
- All Nordic countries provide career education and guidance (CEG) as part of compulsory education. Although the educational systems share common contexts, features, and challenges, there are differences in how career education as a systematic strategy supporting career learning and development is implemented and accessed in each country. This study aims to map and compare career education in compulsory schools in Denmark, the Faroe Islands, Finland, Greenland, Iceland, Norway, and Sweden. In doing so, the aim is to spark further discussion, support development in practice, and identify themes for further research. The analysis focuses on macro-level input for career education and includes each nation’s relevant legislation and curriculum, resulting in a broad comparison consisting of four general parts: 1. National legislation, 2. National curriculum, 3. Organisation and roles, and 4. Quality and evaluation. The comparison revealed that while each country guarantees students the right to career guidance by law and requires a certain level of professionalisation for implementation, national legislation on career education and related curricula differ widely. In all the Nordic countries, career counsellors play a role in supporting career learning alongside teachers, but in most cases neither group’s role is well-defined. Quality processes are rarely in place, but ad hoc evaluations have been conducted. The study and the categories can be utilised to enhance discussion in policy and practice development and guide further research on career education. The comparison identifies leadership in career education as an important topic for future research.
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| 34. |
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| 35. |
- Enblom, Roger, et al.
(author)
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Impact of non-elliptic contact modelling in wheel wear simulation
- 2008
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In: Wear. - : Elsevier BV. - 0043-1648 .- 1873-2577. ; 265:9-10, s. 1532-1541
-
Journal article (peer-reviewed)abstract
- Advances in simulation of railway wheel wear in the sense of material removal have drawn the attention to the importance of wheel–rail contact modelling. As a further step of enhancing the used simulation procedure in direction of increased generality and reduced need for application-dependent calibration, the focus of this investigation is the influence of non-elliptic contact models on the wheel wear rate and profile shape. To facilitate evaluation the semi-Hertzian contact procedure Stripes, developed by INRETS in France, has been implemented. To investigate the capabilities of Stripes to assess the contact area and pressure, shape comparisons have been made with other numerical methods for a set of wheel–rail contact situations. The referenced results are based on the linear elastic half-space assumption, elastic finite element analysis, and elastic–plastic finite element analysis. For reference also the elliptic contact area according to Hertz is shown as given by the contact data table of the multi-body simulation code. After exploring the properties of the Stripes procedure with respect to contact area estimation and pressure distribution, the focus is moved to the influence on wear rate, being the principal objective of this investigation. First the wear distribution over the contact patch is studied and compared to results using the elliptic model from the MBS code Gensys and the non-elliptic approach with Kalker's code Contact. Finally the evolution of the wheel profile is simulated for a few typical cases. This investigation of wear distributions over non-elliptic patches under different operating conditions indicates significant differences compared to both Contact and the applied Hertzian approach. The expansion from single contact occasions to complete simulations indicates comparable material removal rates but relocation towards the flange side. This tendency is apparent in all of the cases shown, however limited to initial wear in tangent run or reasonably mild curve negotiation.
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| 36. |
- Enblom, Roger, 1950-
(author)
-
On Simulation of Uniform Wear and Profile Evolution in the Wheel - Rail Contact
- 2006
-
Doctoral thesis (other academic/artistic)abstract
- Numerical procedures for reliable wheel and rail wear prediction are rare. Recent development of simulation techniques and computer power together with tribological knowledge do however suggest computer aided wear prediction as possible. The present objective is to devise a numerical procedure able to simulate profile evolution due to uniform wear sufficiently accurate for application to vehicle dynamics simulation. Such a tool should be useful for maintenance planning, optimisation of the railway system and its components as well as trouble-shooting. More specifically, the field of application may include estimation of reprofiling frequency, optimisation of wheel – rail profile match, optimisation of running gear suspension parameters, and recognition of unfavourable profile evolution influencing the dynamic response of the vehicle. The research contribution accounted for in this thesis includes, besides a literature review, modelling of the wheel – rail interface, benchmarking against traditional methods, and validation with respect to full-scale measurements. The first part addresses wheel – rail contact conditions in the context of wear simulation as well as tribological environment and tractive forces. The current approach includes Archard’s wear model with associated wear maps, vehicle dynamics simulation, and railway network definition. One objective is to be able to include variations in operation conditions in the set of simulations instead of using scaling factors. In particular the influence of disc braking and varying lubrication conditions have been investigated. Both environmental factors like moist and contamination and deliberate lubrication need to be considered. As part of the associated contact analysis the influence of tangential elastic deformation of the contacting surfaces has been investigated and found to be essential in case of partial slip contact conditions. The influence on the calculated wear of replacing the Hertzian contact by a non-elliptic semi-Hertzian method has been investigated, showing relocation of material loss towards increased profile curvature. In the second part comparisons have been carried out with traditional methods, where the material loss is assumed to be directly related to the energy dissipated in the contact. Attention has been paid to the understanding of the principle differences between the investigated methods, comparing the distribution of friction energy, sliding velocity, and wear depth. As a prerequisite, contact conditions with dependence on wheelset guidance and curving performance as well as influence of tractive forces have been investigated. In the final part validation of the developments related to wheel wear simulation is addressed. Disc braking has been included and a wear map for moist contact conditions based on recent tests has been drafted. Good agreement with measurements from the reference operation, is achieved. Further a procedure for simulation of rail wear and corresponding profile evolution has been formulated. A simulation set is selected defining the vehicles running on the track to be investigated, their operating conditions, and contact parameters. Trial calculations of a few curves show qualitatively good results in terms of profile shape development and difference in wear mechanisms between gauge corner and rail head. The wear rates related to traffic tonnage are however overestimated. The impact of the model improvements accounted for in the first part of the thesis has been investigated, indicating directions for further development.
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| 37. |
- Enblom, Roger, et al.
(author)
-
Proposed procedure and trial simulation of rail profile evolution due to uniform wear
- 2008
-
In: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit. - 0954-4097 .- 2041-3017. ; 222:1, s. 15-25
-
Journal article (peer-reviewed)abstract
- A procedure for numerical simulation of rail wear and the corresponding profile evolution has been formulated. The wear is assumed to be uniform in the sense that the profiles remain constant along the track portion to be investigated. A simulation set is selected defining the vehicles running on the track, their operating conditions, and contact parameters. Several variations of input data may be included together with the corresponding occurrence probability. Simulation of multi-body dynamics is used to calculate contact forces and positions, and Archard's wear equation is applied for the calculation of wear depth. Wear coefficients as a function of contact pressure and relative sliding velocity are collected from different test results. Trial calculations of four non-lubricated and two lubricated curves with radii from 303 to 802 m show qualitatively reasonable results in terms of profile shape development and difference in wear mechanisms between gauge corner and rail head. The wear rates related to traffic tonnage are, however, overestimated and the lubrication efficiency underestimated. It is expected that model refinements in terms of environmental influence and contact stress calculation are useful to improve the quantitative results.
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| 38. |
- Enblom, Roger, et al.
(author)
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Simulation of railway wheel profile development due to wear : influence of disc braking and contact environment
- 2005
-
In: Wear. - : Elsevier. - 0043-1648 .- 1873-2577. ; 258:7-8, s. 1055-1063
-
Journal article (peer-reviewed)abstract
- This paper addresses issues related to braking and wheel-rail contact conditions in the context of wheel wear simulation. The KTH approach to the topic includes Archard's wear model with associated wear maps, vehicle dynamics simulation and railway network definition. In previous work at KTH certain variations in operating conditions have been accounted for through empirically estimated average scaling factors. The objective of the current research is to be able to include such variations in the set of simulations. In particular the influence of disc braking as well as varying friction and lubrication conditions are investigated. Both environmental factors like moist and contamination and deliberate lubrication need to be considered. As part of the associated contact analysis the influence of local elastic deformation on the sliding velocity has been separately investigated.
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| 39. |
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| 40. |
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| 41. |
- Enblom, Roger, et al.
(author)
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Wheel Wear Modelling Including Disc Braking and Contact Environment : Simulation of 18 Months of Commuter Service in Stockholm
- 2004
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In: Proceedings of the 14th International Wheelset Congress.
-
Conference paper (other academic/artistic)abstract
- This paper addresses some aspects of modelling and validation of wheel wear simulation. In previous work at KTH the influences of braking and lubrication have been accounted for through empirically estimated average scaling factors. The current research shows how to include those effects in the set of simulations instead. Disc braking has been included in the simulation set and a wear map for moist contact conditions based on recent tribometer tests has been drafted and tested. Good agreement with measurements from theStockholmcommuter service is achieved. It is concluded that the model improvements accounted for are sufficient for adequate simulation of tread wear but that further development of the flange / gauge corner contact modelling is needed.
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| 42. |
- Engert, Andreas, et al.
(author)
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The European Hematology Association Roadmap for European Hematology Research : a consensus document
- 2016
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In: Haematologica. - Pavia, Italy : Ferrata Storti Foundation (Haematologica). - 0390-6078 .- 1592-8721. ; 101:2, s. 115-208
-
Journal article (peer-reviewed)abstract
- The European Hematology Association (EHA) Roadmap for European Hematology Research highlights major achievements in diagnosis and treatment of blood disorders and identifies the greatest unmet clinical and scientific needs in those areas to enable better funded, more focused European hematology research. Initiated by the EHA, around 300 experts contributed to the consensus document, which will help European policy makers, research funders, research organizations, researchers, and patient groups make better informed decisions on hematology research. It also aims to raise public awareness of the burden of blood disorders on European society, which purely in economic terms is estimated at (sic)23 billion per year, a level of cost that is not matched in current European hematology research funding. In recent decades, hematology research has improved our fundamental understanding of the biology of blood disorders, and has improved diagnostics and treatments, sometimes in revolutionary ways. This progress highlights the potential of focused basic research programs such as this EHA Roadmap. The EHA Roadmap identifies nine 'sections' in hematology: normal hematopoiesis, malignant lymphoid and myeloid diseases, anemias and related diseases, platelet disorders, blood coagulation and hemostatic disorders, transfusion medicine, infections in hematology, and hematopoietic stem cell transplantation. These sections span 60 smaller groups of diseases or disorders. The EHA Roadmap identifies priorities and needs across the field of hematology, including those to develop targeted therapies based on genomic profiling and chemical biology, to eradicate minimal residual malignant disease, and to develop cellular immunotherapies, combination treatments, gene therapies, hematopoietic stem cell treatments, and treatments that are better tolerated by elderly patients.
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| 43. |
- Henriksson, Roger, et al.
(author)
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High-grade astrocytoma treated concomitantly with estramustine and radiotherapy.
- 2006
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In: Journal of neuro-oncology. - : Springer Science and Business Media LLC. - 0167-594X .- 1573-7373. ; 78:3, s. 321-6
-
Journal article (peer-reviewed)abstract
- Experimental and early clinical investigations have demonstrated encouraging results for estramustine in the treatment of malignant glioma. The present study is an open randomized clinical trial comparing estramustine phosphate (Estracyt) in addition to radiotherapy with radiotherapy alone as first line treatment of astrocytoma grade III and IV. The 140 patients included were in a good clinical condition with a median age of 55 years (range 22-87). Estramustine was given orally, 280 mg twice daily, as soon as the diagnosis was established, during and after the radiotherapy for a period of in total 3 months. Radiotherapy was delivered on weekdays 2 Gy daily up to 56 Gy. Eighteen patients were excluded due to misclassification, leaving 122 patients eligible for evaluation. Overall the treatment was well tolerated. Mild or moderate nausea was the most common side effect of estramustine. The minimum follow-up time was 5.2 years for the surviving patients. For astrocytoma grade III the median survival time was 10.6 (1.3-92.7) months for the radiotherapy only group and 17.3 (0.4-96.9+) months for the estramustine + radiotherapy group. In grade IV the corresponding median survival time was 12.3 (2.1-89.2) and 10.3 (0.3-91.7+) months, respectively. Median time to progress for radiotherapy only and radiotherapy and estramustin group in grade III tumours was 6.5 and 10.1 months, respectively. In grade IV tumours the corresponding figures were 5.1 and 3.3 months, respectively. Although there was a tendency for improved survival in grade III, no statistical significant differences were found between the treatment groups. No differences between the two treatment groups were evident with respect to quality of life according to the EORTC QLQ-protocol. In conclusion, this first randomized study did not demonstrate any significant improvement of using estramustine in addition to conventional radiotherapy, however, a trend for a positive response for the estramustine group was found in patients with grade III glioma.
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| 44. |
- Hollestelle, Antoinette, et al.
(author)
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No clinical utility of KRAS variant rs61764370 for ovarian or breast cancer
- 2016
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In: Gynecologic Oncology. - : Elsevier BV. - 0090-8258 .- 1095-6859. ; 141:2, s. 386-401
-
Journal article (peer-reviewed)abstract
- Objective Clinical genetic testing is commercially available for rs61764370, an inherited variant residing in a KRAS 3′ UTR microRNA binding site, based on suggested associations with increased ovarian and breast cancer risk as well as with survival time. However, prior studies, emphasizing particular subgroups, were relatively small. Therefore, we comprehensively evaluated ovarian and breast cancer risks as well as clinical outcome associated with rs61764370. Methods Centralized genotyping and analysis were performed for 140,012 women enrolled in the Ovarian Cancer Association Consortium (15,357 ovarian cancer patients; 30,816 controls), the Breast Cancer Association Consortium (33,530 breast cancer patients; 37,640 controls), and the Consortium of Modifiers of BRCA1 and BRCA2 (14,765 BRCA1 and 7904 BRCA2 mutation carriers). Results We found no association with risk of ovarian cancer (OR = 0.99, 95% CI 0.94-1.04, p = 0.74) or breast cancer (OR = 0.98, 95% CI 0.94-1.01, p = 0.19) and results were consistent among mutation carriers (BRCA1, ovarian cancer HR = 1.09, 95% CI 0.97-1.23, p = 0.14, breast cancer HR = 1.04, 95% CI 0.97-1.12, p = 0.27; BRCA2, ovarian cancer HR = 0.89, 95% CI 0.71-1.13, p = 0.34, breast cancer HR = 1.06, 95% CI 0.94-1.19, p = 0.35). Null results were also obtained for associations with overall survival following ovarian cancer (HR = 0.94, 95% CI 0.83-1.07, p = 0.38), breast cancer (HR = 0.96, 95% CI 0.87-1.06, p = 0.38), and all other previously-reported associations. Conclusions rs61764370 is not associated with risk of ovarian or breast cancer nor with clinical outcome for patients with these cancers. Therefore, genotyping this variant has no clinical utility related to the prediction or management of these cancers.
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| 45. |
- Hop, Paul J., et al.
(author)
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Genome-wide study of DNA methylation shows alterations in metabolic, inflammatory, and cholesterol pathways in ALS
- 2022
-
In: Science Translational Medicine. - : American Association for the Advancement of Science. - 1946-6234 .- 1946-6242. ; 14:633
-
Journal article (peer-reviewed)abstract
- Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with an estimated heritability between 40 and 50%. DNA methylation patterns can serve as proxies of (past) exposures and disease progression, as well as providing a potential mechanism that mediates genetic or environmental risk. Here, we present a blood-based epigenome-wide association study meta-analysis in 9706 samples passing stringent quality control (6763 patients, 2943 controls). We identified a total of 45 differentially methylated positions (DMPs) annotated to 42 genes, which are enriched for pathways and traits related to metabolism, cholesterol biosynthesis, and immunity. We then tested 39 DNA methylation-based proxies of putative ALS risk factors and found that high-density lipoprotein cholesterol, body mass index, white blood cell proportions, and alcohol intake were independently associated with ALS. Integration of these results with our latest genome-wide association study showed that cholesterol biosynthesis was potentially causally related to ALS. Last, DNA methylation at several DMPs and blood cell proportion estimates derived from DNA methylation data were associated with survival rate in patients, suggesting that they might represent indicators of underlying disease processes potentially amenable to therapeutic interventions.
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| 46. |
- Huyghe, Jeroen R., et al.
(author)
-
Discovery of common and rare genetic risk variants for colorectal cancer
- 2019
-
In: Nature Genetics. - : Nature Publishing Group. - 1061-4036 .- 1546-1718. ; 51:1, s. 76-
-
Journal article (peer-reviewed)abstract
- To further dissect the genetic architecture of colorectal cancer (CRC), we performed whole-genome sequencing of 1,439 cases and 720 controls, imputed discovered sequence variants and Haplotype Reference Consortium panel variants into genome-wide association study data, and tested for association in 34,869 cases and 29,051 controls. Findings were followed up in an additional 23,262 cases and 38,296 controls. We discovered a strongly protective 0.3% frequency variant signal at CHD1. In a combined meta-analysis of 125,478 individuals, we identified 40 new independent signals at P < 5 x 10(-8), bringing the number of known independent signals for CRC to similar to 100. New signals implicate lower-frequency variants, Kruppel-like factors, Hedgehog signaling, Hippo-YAP signaling, long noncoding RNAs and somatic drivers, and support a role for immune function. Heritability analyses suggest that CRC risk is highly polygenic, and larger, more comprehensive studies enabling rare variant analysis will improve understanding of biology underlying this risk and influence personalized screening strategies and drug development.
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| 47. |
- Jacobs, Kevin B, et al.
(author)
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Detectable clonal mosaicism and its relationship to aging and cancer.
- 2012
-
In: Nature Genetics. - New York : Nature Publishing Group. - 1061-4036 .- 1546-1718. ; 44:6, s. 651-658
-
Journal article (peer-reviewed)abstract
- In an analysis of 31,717 cancer cases and 26,136 cancer-free controls from 13 genome-wide association studies, we observed large chromosomal abnormalities in a subset of clones in DNA obtained from blood or buccal samples. We observed mosaic abnormalities, either aneuploidy or copy-neutral loss of heterozygosity, of >2 Mb in size in autosomes of 517 individuals (0.89%), with abnormal cell proportions of between 7% and 95%. In cancer-free individuals, frequency increased with age, from 0.23% under 50 years to 1.91% between 75 and 79 years (P = 4.8 × 10(-8)). Mosaic abnormalities were more frequent in individuals with solid tumors (0.97% versus 0.74% in cancer-free individuals; odds ratio (OR) = 1.25; P = 0.016), with stronger association with cases who had DNA collected before diagnosis or treatment (OR = 1.45; P = 0.0005). Detectable mosaicism was also more common in individuals for whom DNA was collected at least 1 year before diagnosis with leukemia compared to cancer-free individuals (OR = 35.4; P = 3.8 × 10(-11)). These findings underscore the time-dependent nature of somatic events in the etiology of cancer and potentially other late-onset diseases.
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| 48. |
- Johansson, Jonas, et al.
(author)
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Time-Resolved Studies of Light Propagation in Crassula and Phaseolus Leaves
- 1999
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In: Photochemistry and Photobiology. - 0031-8655. ; 69:2, s. 242-247
-
Journal article (peer-reviewed)abstract
- Time-resolved transmittance was used to extract in vivo optical properties of leaves of green plants experimentally. In time-resolved transmittance measurements an ultrashort light pulse is directed onto the surface of the object and the transmitted light is measured with a time resolution in the range of picoseconds. A table-top terawatt laser was used to generate 200 fs light pulses at 790 nm with a repetition rate of 10 Hz. The light pulses were focused through a cuvette filled with water to produce white light pulses and optical filters were placed in the beam path to select the wavelength of the light focused onto the leaf surface. The time profiles of the light transmitted through the leaves was recorded with a streak camera having a time resolution of about 2.5 ps. Results from Crassula falcata and Phaseolus vulgaris studied at 550, 670 and 740 nm are reported. The three selected wavelength regions represent medium, high and a low absorption of light, respectively. A library of curves was generated using Monte Carlo simulation, and the absorption and scattering coefficients were extracted by comparison of experimental curves with this library. Our results suggest that in the case of the thin (200 μm) Phaseolus leaves and certainly in the case of the thick (4 mm) Crassula leaves, light scattering plays an important role in light transport through the leaf and should also affect light flux in these leaves.
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| 49. |
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| 50. |
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