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| 2. |
- Risgaard-Petersen, N., et al.
(författare)
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Evidence for complete denitrification in a benthic foraminifer
- 2006
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 443:7107, s. 93-96
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Tidskriftsartikel (refereegranskat)abstract
- Benthic foraminifera are unicellular eukaryotes found abundantly in many types of marine sediments. Many species survive and possibly reproduce in anoxic habitats(1), but sustainable anaerobic metabolism has not been previously described. Here we demonstrate that the foraminifer Globobulimina pseudospinescens accumulates intracellular nitrate stores and that these can be respired to dinitrogen gas. The amounts of nitrate detected are estimated to be sufficient to support respiration for over a month. In a Swedish fjord sediment where G. pseudospinescens is the dominant foraminifer, the intracellular nitrate pool in this species accounted for 20% of the large, cell-bound, nitrate pool present in an oxygen-free zone. Similarly high nitrate concentrations were also detected in foraminifera Nonionella cf. stella and a Stainforthia species, the two dominant benthic taxa occurring within the oxygen minimum zone of the continental shelf off Chile. Given the high abundance of foraminifera in anoxic marine environments(1-3), these new findings suggest that foraminifera may play an important role in global nitrogen cycling and indicate that our understanding of the complexity of the marine nitrogen cycle is far from complete.
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| 3. |
- Brown, Kevin M., et al.
(författare)
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Common sequence variants on 20q11.22 confer melanoma susceptibility
- 2008
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 40:7, s. 838-840
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Tidskriftsartikel (refereegranskat)abstract
- We conducted a genome-wide association pooling study for cutaneous melanoma and performed validation in samples totaling 2,019 cases and 2,105 controls. Using pooling, we identified a new melanoma risk locus on chromosome 20 (rs910873 and rs1885120), with replication in two further samples (combined P < 1 x 10(-15)). The per allele odds ratio was 1.75 (1.53, 2.01), with evidence for stronger association in early-onset cases.
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| 4. |
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| 5. |
- Gustafson, Johan, et al.
(författare)
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One-dimensional PtO(2) at Pt steps : Formation and reaction with CO
- 2005
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 95:25, s. 1-4
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Tidskriftsartikel (refereegranskat)abstract
- Using core-level spectroscopy and density functional theory we show that a one-dimensional (1D) PtO(2) oxide structure forms at the steps of the Pt(332) surface after O(2) exposure. The 1D oxide is found to be stable in an oxygen pressure range, where bulk oxides are only metastable, and is therefore argued to be a precursor to the Pt oxidation. As an example of the consequences of such a precursor exclusively present at the steps, we investigate the reaction of CO with oxygen covered Pt(332). Albeit more strongly bound, the oxidic oxygen is found to react more easily with CO than oxygen chemisorbed on the Pt terraces.
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| 7. |
- Schmid, M. C., et al.
(författare)
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Anaerobic ammonium-oxidizing bacteria in marine environments: widespread occurrence but low diversity
- 2007
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Ingår i: Environmental Microbiology. - : Wiley. - 1462-2912 .- 1462-2920. ; 9:6, s. 1476-1484
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Tidskriftsartikel (refereegranskat)abstract
- Laboratory and field studies have indicated that anaerobic ammonium oxidation (anammox) is an important process in the marine nitrogen cycle. In this study 11 additional anoxic marine sediment and water column samples were studied to substantiate this claim. In a combined approach using the molecular methods, polymerase chain reaction (PCR), qualitative and quantitative fluorescence in situ hybridization (FISH), as well as N-15 stable isotope activity measurements, it was shown that anammox bacteria were present and active in all samples investigated. The anammox activity measured in the sediment samples ranged from 0.08 fmol cell(-1) day(-1) N-2 in the Golfo Dulce (Pacific Ocean, Costa Rica) sediment to 0.98 fmol cell(-1) day(-1) N-2 in the Gullmarsfjorden (North Sea, Sweden) sediment. The percentage of anammox cell of the total population (stained with DAPI) as assessed by quantitative FISH was highest in the Barents Sea (9% +/- 4%) and in most of the samples well over 2%. Fluorescence in situ hybridization and phylogenetic analysis of the PCR products derived from the marine samples indicated the exclusive presence of members of the Candidatus 'Scalindua' genus. This study showed the ubiquitous presence of anammox bacteria in anoxic marine ecosystems, supporting previous observations on the importance of anammox for N cycling in marine environments.
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| 8. |
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| 9. |
- Westerström, Rasmus, et al.
(författare)
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Stressing Pd atoms: Initial oxidation of the Pd(110) surface
- 2008
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Ingår i: Surface Science. - : Elsevier BV. - 0039-6028. ; 602:14, s. 2440-2447
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated the oxygen induced structures of the Pd(1 1 0) surface in the pressure range of 10(-5)-10(-3) mbar of oxygen, at a sample temperature of around 300 degrees C. These structures, denoted as "(7 x root 3)" and "(9 x root 3)", are studied in detail by the use of a combination of low-energy electron diffraction, scanning tunneling microscopy, high-resolution core level spectroscopy, and ab-initio simulations. Based on our data a model is proposed for these structures containing segments of Pd atoms in the [1 (1) over bar0] direction, in which the Pd rows are decorated by O atoms in a zig-zag pattern. The segments are periodically separated by displaced Pd atoms. Density functional theory calculations show that the displacements reduce the oxygen induced stress significantly, as compared to a structure with no displacements. The calculations also suggest that the new structures are stabilized by domain formation. (C) 2008 Elsevier B.V. All rights reserved.
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| 10. |
- Aus, Gunnar, 1958, et al.
(författare)
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EAU Guidelines on Prostate Cancer.
- 2005
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Ingår i: Eur Urol. - : Elsevier BV. ; 48:4, s. 546-551
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The first summary of the European Association of Urology (EAU) guidelines on prostate cancer was published in 2001. These guidelines have been continuously updated since many important changes affecting the clinical management of patients with prostate cancer have occurred over the past years. The aim of this paper is to present a summary of the 2005 update of the EAU guidelines on prostate cancer. Methods: A literature review of the new data has been performed by the working panel. The guidelines have been updated and level of evidence/grade of recommendation added to the text. This enables readers to better understand the quality of the data forming the basis of the recommendations. Results: A full version is available at the EAU Office or at www.uroweb.org. Systemic prostate biopsies under ultrasound guidance is the preferred diagnostic method and the use of periprostatic injection of a local anaesthetic can significantly reduce pain/discomfort associated with the procedure. Active treatment (surgery or radiation) is mostly recommended for patients with localized disease and a long life expectancy with radical prostatectomy being the only treatment evaluated in a randomized controlled trial. Follow-up is at large based on prostate specific antigen (PSA) and a disease-specific history with imaging only indicated when symptoms occur. Cytotoxic therapy has become an option for selected patients with hormone refractory prostate cancer. Conclusion: The knowledge in the field of prostate cancer is rapidly changing. These EAU guidelines on prostate cancer summarize the most recent findings and put them into clinical practice.
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