| 1. |
- Strauss, Harald, et al.
(författare)
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Multiple sulphur and oxygen isotopes reveal microbial sulphur cycling in spring waters in the Lower Engadin, Switzerland
- 2016
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Ingår i: Isotopes in environmental and health studies. - : Informa UK Limited. - 1025-6016 .- 1477-2639. ; 52:1-2, s. 75-93
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Tidskriftsartikel (refereegranskat)abstract
- Highly mineralized springs in the Scuol-Tarasp area of the Lower Engadin and in the Albula Valley near Alvaneu, Switzerland, display distinct differences with respect to the source and fate of their dissolved sulphur species. High sulphate concentrations and positive sulphur (delta S-34) and oxygen (delta O-18) isotopic compositions argue for the subsurface dissolution of Mesozoic evaporitic sulphate. In contrast, low sulphate concentrations and less positive or even negative delta S-34 and delta O-18 values indicate a substantial contribution of sulphate sulphur from the oxidation of sulphides in the crystalline basement rocks or the Jurassic sedimentary cover rocks. Furthermore, multiple sulphur (delta S-34, Delta S-33) isotopes support the identification of microbial sulphate reduction and sulphide oxidation in the subsurface, the latter is also evident through the presence of thick aggregates of sulphide-oxidizing Thiothrix bacteria.
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| 2. |
- Fieselmann, Andreas, et al.
(författare)
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Volumetric breast density measurement for personalized screening : Accuracy, reproducibility, consistency, and agreement with visual assessment
- 2019
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Ingår i: Journal of Medical Imaging. - 2329-4302. ; 6:3
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Tidskriftsartikel (refereegranskat)abstract
- Assessment of breast density at the point of mammographic examination could lead to optimized breast cancer screening pathways. The onsite breast density information may offer guidance of when to recommend supplemental imaging for women in a screening program. A software application (Insight BD, Siemens Healthcare GmbH) for fast onsite quantification of volumetric breast density is evaluated. The accuracy of the method is assessed using breast tissue equivalent phantom experiments resulting in a mean absolute error of 3.84%. Reproducibility of measurement results is analyzed using 8427 exams in total, comparing for each exam (if available) the densities determined from left and right views, from cranio-caudal and medio-lateral oblique views, from full-field digital mammograms (FFDM) and digital breast tomosynthesis (DBT) data and from two subsequent exams of the same breast. Pearson correlation coefficients of 0.937, 0.926, 0.950, and 0.995 are obtained. Consistency of the results is demonstrated by evaluating the dependency of the breast density on women's age. Furthermore, the agreement between breast density categories computed by the software with those determined visually by 32 radiologists is shown by an overall percentage agreement of 69.5% for FFDM and by 64.6% for DBT data. These results demonstrate that the software delivers accurate, reproducible, and consistent measurements that agree well with the visual assessment of breast density by radiologists.
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| 3. |
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| 4. |
- Lu, Lu, et al.
(författare)
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Rhamnolipid Biosurfactants Enhance Microbial Oil Biodegradation in Surface Seawater from the North Sea
- 2023
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Ingår i: ACS - ES & T Water. - : American Chemical Society (ACS). - 2690-0637. ; 3:8, s. 2255-2266
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Tidskriftsartikel (refereegranskat)abstract
- This study provides strong evidence thatthe biosurfactantrhamnolipid is more efficient than the widely used chemical dispersantsCorexit 9500 and Slickgone NS in stimulating oil biodegradation innatural seawater. Biosurfactants arepromising alternatives to chemical dispersantsfor combating marine oil spills; however, the impacts of biosurfactantson microbial community composition and oil biodegradation activitiesremain largely unknown. Here, we conducted a time-course microcosmexperiment mimicking oil spill scenarios with surface seawater fromthe North Sea, amended with either the biosurfactant rhamnolipid ora dispersant (Corexit 9500 or Slickgone NS). Radioactive tracer assaysto track hexadecane and naphthalene oxidation as well as bacterialproduction revealed the highest hydrocarbon oxidation rates and generalmicrobial activities in the rhamnolipid-amended oil microcosms, followedby oil microcosms with Slickgone and Corexit. Impacts on the microbialcommunity composition differed among treatments, and growth of oil-degrading Colwellia was stimulated remarkably in Corexit-amended oiland oil-only microcosms, while potential oil-degrading Oleispira were highly enriched in the presence of oil in combination withrhamnolipid or Slickgone. Furthermore, increased abundances of Colwellia and Oleispira, and stimulatedbacterial production in microcosms with only rhamnolipid, Corexit,or Slickgone, indicated their involvement in biosurfactant/dispersantbiodegradation. Our findings highlight varying microbial impacts resultingfrom rhamnolipid and chemical dispersants and suggest great promisefor the application of biosurfactants in future marine oil spills.
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