| 1. |
- 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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| 2. |
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| 3. |
- Knapp, M., et al.
(författare)
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Unusual process of water formation on RuO2(110) by hydrogen exposure at room temperature
- 2006
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Ingår i: The Journal of Physical Chemistry Part B. - : American Chemical Society (ACS). - 1520-5207 .- 1520-6106. ; 110:29, s. 14007-14010
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Tidskriftsartikel (refereegranskat)abstract
- The reduction mechanism of the RuO2(110) surface by molecular hydrogen exposure is unraveled to an unprecedented level by a combination of temperature programmed reaction, scanning tunneling microscopy, high-resolution core level shift spectroscopy, and density functional theory calculations. We demonstrate that even at room temperature hydrogen exposure to the RuO2(110) surface leads to the formation of water. In a two-step process, hydrogen saturates first the bridging oxygen atoms to form (O-br-H) species and subsequently part of these O-br-H groups move to the undercoordinated Ru atoms where they form adsorbed water. This latter process is driven by thermodynamics leaving vacancies in the bridging O rows.
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| 4. |
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| 5. |
- 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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| 6. |
- Gustafson, Johan, et al.
(författare)
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Structure of a thin oxide film on Rh(100)
- 2005
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Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 71:11
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Tidskriftsartikel (refereegranskat)abstract
- The initial oxidation of Rh(100) has been studied using high resolution core level spectroscopy, low energy electron diffraction, surface x-ray diffraction, scanning tunneling microscopy, and density functional theory. We report a structural study of an oxygen induced structure displaying a c(8x2) periodicity at an oxygen pressure above 10(-5) mbar and using a sample temperature of 700 K. Our experimental and theoretical data demonstrate that this structure is due to the formation of a thin surface oxide with a hexagonal trilayer O-Rh-O structure.
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| 7. |
- Schmid, F., et al.
(författare)
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Bidirectional tensile testing cell for in situ small angle X-ray scattering investigations of soft tissue
- 2006
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Ingår i: Nuclear Instruments and Methods in Physics Research Section B. - : Elsevier BV. - 0168-583X .- 1872-9584. ; 246:1, s. 262-268
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Tidskriftsartikel (refereegranskat)abstract
- An X-ray cell for the acquisition of one-dimensional mechanical force-displacement diagrams of soft tissue samples has been developed. The combination of X-ray and mechanical data allows new insights into the coupling of the macroscopic behavior and nanoscopic structural changes during the application of load. Two linear mu-translation stages are used to symmetrically - i.e. bidirectionally - stretch the sample. A video-extensometer is installed to record geometrical changes of the sample during measurement which allows to determine true stresses and strains. The sample can be immersed in a liquid and heated. We demonstrate the advantages over common unidirectional tensile testing devices without length measurement systems by comparing different mechanical and diffraction data sets of human arterial tissue.
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| 8. |
- Schmid, F., et al.
(författare)
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In situ tensile testing of human aortas by time-resolved small-angle X-ray scattering
- 2005
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Ingår i: Journal of Synchrotron Radiation. - 0909-0495 .- 1600-5775. ; 12, s. 727-733
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Tidskriftsartikel (refereegranskat)abstract
- The collagen diffraction patterns of human aortas under uniaxial tensile test conditions have been investigated by synchrotron small- angle X- ray scattering. Using a recently designed tensile testing device the orientation and d- spacing of the collagen fibers in the adventitial layer have been measured in situ with the macroscopic force and sample stretching under physiological conditions. The results show a direct relation between the orientation and extension of the collagen fibers on the nanoscopic level and the macroscopic stress and strain. This is attributed first to a straightening, second to a reorientation of the collagen fibers, and third to an uptake of the increasing loads by the collagen fibers.
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| 9. |
- Schmid, M, et al.
(författare)
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Structure of Ag(111)-p(4x4)-O: No silver oxide
- 2006
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Ingår i: Physical Review Letters. - 1079-7114. ; 96:14
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Tidskriftsartikel (refereegranskat)abstract
- The structure of the oxygen-induced p(4x4) reconstruction of Ag(111) is determined by a combination of scanning tunneling microscopy, surface x-ray diffraction, core level spectroscopy, and density functional theory. We demonstrate that all previous models of this surface structure are incorrect and propose a new model which is able to explain all our experimental findings but has no resemblance to bulk silver oxide. We also shed some light on the limitations of current density functional theories and the potential role of van der Waals interactions in the stabilization of oxygen-induced surface reconstructions of noble metals.
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