| 1. |
- Chan, Simon S. M., et al.
(författare)
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Body Mass Index and the Risk for Crohn's Disease and Ulcerative Colitis : Data From a European Prospective Cohort Study (The IBD in EPIC Study)
- 2013
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Ingår i: American Journal of Gastroenterology. - New York, NY, USA : Nature Publishing Group. - 0002-9270 .- 1572-0241. ; 108:4, s. 575-582
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Obesity is associated with a proinflammatory state that may be involved in the etiology of inflammatory bowel disease (IBD), for which there are plausible biological mechanisms. Our aim was to perform the first prospective cohort study investigating if there is an association between obesity and the development of incident IBD. METHODS: A total of 300,724 participants were recruited into the European Prospective Investigation into Cancer and Nutrition study. At recruitment, anthropometric measurements of height and weight plus physical activity and total energy intake from validated questionnaires were recorded. The cohort was monitored identifying participants who developed either Crohn's disease (CD) or ulcerative colitis (UC). Each case was matched with four controls and conditional logistic regression used to calculate odds ratios (ORs) for body mass index (BMI) adjusted for smoking, energy intake, and physical activity. RESULTS: In the cohort, 177 participants developed incident UC and 75 participants developed incident CD. There were no associations with the four higher categories of BMI compared with a normal BMI for UC (P-trend = 0.36) or CD (P-trend = 0.83). The lack of associations was consistent when BMI was analyzed as a continuous or binary variable (BMI 18.5 <25.0 vs. >= 25 kg/m(2)). Physical activity and total energy intake, factors that influence BMI, did not show any association with UC (physical activity, P-trend = 0.79; total energy intake, P-trend = 0.18) or CD (physical activity, P-trend = 0.42; total energy, P-trend = 0.11). CONCLUSIONS: Obesity as measured by BMI is not associated with the development of incident UC or CD. Alternative measures of obesity are required to further investigate the role of obesity in the development of incident IBD.
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| 2. |
- Hart, Andrew R, et al.
(författare)
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Diet in the aetiology of ulcerative colitis: A European prospective cohort study
- 2008
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Ingår i: Digestion. - : S. Karger AG. - 1421-9867 .- 0012-2823. ; 77:1, s. 57-64
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Tidskriftsartikel (refereegranskat)abstract
- Background/Aims: The causes of ulcerative colitis are unknown, although it is plausible that dietary factors are involved. Case-control studies of diet and ulcerative colitis are subject to recall biases. The aim of this study was to examine the prospective relationship between the intake of nutrients and the development of ulcerative colitis in a cohort study. Methods: The study population was 260,686 men and women aged 20-80 years, participating in a large European prospective cohort study (EPIC). Participants were residents in the UK, Sweden, Denmark, Germany or Italy. Information on diet was supplied and the subjects were followed up for the development of ulcerative colitis. Each incident case was matched with four controls and dietary variables were divided into quartiles. Results: A total of 139 subjects with incident ulcerative colitis were identified. No dietary associations were detected, apart from a marginally significant positive association with an increasing percentage intake of energy from total polyunsaturated fatty acids (trend across quartiles OR = 1.19 (95% CI = 0.99-1.43) p = 0.07). Conclusions: No associations between ulcerative colitis and diet were detected, apart from a possible increased risk with a higher total polyunsaturated fatty acid intake. A biological mechanism exists in that polyunsaturated fatty acids are metabolised to pro-inflammatory mediators.
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| 3. |
- Saubin, Elodie, et al.
(författare)
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Comparative field study of shallow rhyolite intrusions in Iceland : Emplacement mechanisms and impact on country rocks
- 2019
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Ingår i: Journal of Volcanology and Geothermal Research. - : ELSEVIER. - 0377-0273 .- 1872-6097. ; 388
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Tidskriftsartikel (refereegranskat)abstract
- Shallow silicic intrusions are known to exist in many active volcanoes and can fuel both eruptions and hydrothermal fields. However, our knowledge of magma intrusions remains far from complete, and processes occurring at intrusion margins are poorly understood. In this field-based study, we characterise four shallows, dissected rhyolitic intrusions at three sites in Iceland (Njarovik-Dyrfjoll, Krafla and Husafell central volcanoes). We focus on the relationship between intrusion emplacement mechanisms and country rock response, employing scanline mapping of fractures and in-situ rock property measurements (hardness and permeability) along transects from the intrusion margins to damaged and undamaged country rocks. We identify various scenarios of shallow intrusion emplacement style, based upon their diverse geometry and lithofacies architecture. Additional information from rock properties and characteristics of fractures and vesicles, indicates that initial country rock properties strongly influence the emplacement style. We identify two discrete types of country rock response to magma injection. The matrix permeability of weak, porous and permeable lithologies (conglomerate and hyaloclastite) is reduced by >1 order of magnitude adjacent to intrusions due to pore occlusion. Stronger and denser, low-permeability lithologies (basalt and welded ignimbrite) undergo a decrease in hardness by a factor >2 related to an up to fivefold increase in fracture density, with no significant change in matrix permeability. Our observations highlight the importance of robust characterisation of the mechanical properties of caldera-filling or geothermal reservoir formations, for appropriate forecasting of magma mobility, geophysical data interpretation, and geothermal resources characterisation.
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| 4. |
- Schipper, C. Ian, et al.
(författare)
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Silicic conduits as supersized tuffisites : Clastogenic influences on shifting eruption styles at Cordon Caulle volcano (Chile)
- 2021
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Ingår i: Bulletin of Volcanology. - : Springer Nature. - 0258-8900 .- 1432-0819. ; 83:2
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the processes that drive explosive-effusive transitions during large silicic eruptions is crucial to hazard mitigation. Conduit models usually treat magma ascent and degassing as a gradual, unidirectional progression from bubble nucleation through magmatic fragmentation. However, there is growing evidence for the importance of bi-directional clastogenic processes that sinter fragmented materials into coherent clastogenic magmas. Bombs that were ejected immediately before the first emergence of lava in the 2011-2012 eruption at Cordon Caulle volcano (Chile) are texturally heterogeneous composite assemblages of welded pyroclastic material. Although diverse in density and appearance, SEM and X-ray tomographic analysis show them all to have been formed by multi-generational viscous sintering of fine ash. Sintering created discrete clasts ranging from obsidian to pumice and formed a pervasive clast-supporting matrix that assembled these clasts into a conduit-sealing plug. An evaluation of sintering timescales reveals texturally disparate bomb components to represent only minutes of difference in residence time within the conduit. Permeability modelling indicates that the plug was an effective conduit seal, with outgassing potential-even from high-porosity regions-being limited by the inability of gas to flow across tendrils of densely sintered inter-clast matrix. Contrary to traditional perspectives, declining expressions of explosivity at the surface need not be preceded or accompanied by a decline in fragmentation efficiency. Instead, they result from tips in balance between the opposing processes of fragmentation and sintering that occur in countless cycles within volcanic conduits. These processes may be particularly enhanced at silicic fissure volcanoes, which have laterally extensive subsurface plumbing systems that require complex magma ascent pathways. The textures investigated here reveal the processes occurring within silicic fissures to be phenomenologically identical to those that have been inferred to occur in tuffisite veins: silicic conduits are essentially supersized examples of edifice-penetrating tuffisites.
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| 5. |
- Thompson, Alex, et al.
(författare)
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Hyperspectral fluorescence lifetime fibre probe spectroscopy for use in the study and diagnosis of osteoarthritis and skin cancer
- 2011
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Ingår i: Optical Biopsy IX. - : SPIE. - 1605-7422. - 9780819484321 ; 7895
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Konferensbidrag (refereegranskat)abstract
- We present the application of two fibre-optic-coupled time-resolved spectrofluorometers and a compact steady-state diffuse reflected light/fluorescence spectrometer to in vivo and ex vivo studies of skin cancer and osteoarthritis. In a clinical study of skin cancer, 27 lesions on 25 patients were investigated in vivo before surgical excision of the region measured. Preliminary analysis reveals a statistically significant decrease in the autofluorescence lifetime of basal cell carcinomas compared to neighbouring healthy tissue. A study of autofluorescence signals associated with the onset of osteoarthritis indicates autofluorescence lifetime changes associated with collagen degradation.
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| 6. |
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- 2019
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Tidskriftsartikel (refereegranskat)
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