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Sökning: WFRF:(Seitz Steffen)

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1.
  • Böttcher, Melanie, et al. (författare)
  • Comparison of in vitro and in situ genotoxicity in the Danube River by means of the comet assay and the micronucleus test
  • 2010
  • Ingår i: Mutation research. Genetic toxicology and environmental mutagenesis. - Amsterdam, Neteherlands : Elsevier. - 1383-5718 .- 1879-3592. ; 700:1-2, s. 11-17
  • Tidskriftsartikel (refereegranskat)abstract
    • Genotoxicity can be correlated with adverse reproductive effects or may even result in elevated extinction risk for particular species of an ecosystem. It may thus be a valuable tool for screening of pollution and potential environmental harm. Since many genotoxicants tend to adsorb on to particulate matter, sediments and suspended materials are of particular interest for genotoxicity screening under field conditions. In order to correlate the genotoxic potential of sediments with genetic damage in fish, rainbow-trout liver (RTL-W1) cells were exposed in vitro to acetone extracts of sediments collected at 10 selected sites along the upper Danube River and analyzed in the comet and micronucleus assays. These in vitro results were compared with micronucleus formation in erythrocytes of the European barbel (Barbus barbus) caught int he field. The two in vitro bioassays showed excellent correlation, indicating comparability of genotoxic potentials in vitro. Sampling sites could be clearly differentiated with respect to severity of effects, with Rottenacker as the most heavily contaminated site, Ehingen and Schwarzach as moderately genotoxic,and with the weakest effects in the tributary Lauchert. All other sediment extracts showed intermediate genotoxic or clastogenic effects. In situ, micronucleus formation in barbel erythrocytes indicated severe genotoxicity at Rottenacker, moderate effects at Ehingen, but minor contamination at Riedlingen and Sigmaringen. In situ observations thus showed excellent correlation with corresponding in vitro tests and document the ecological relevance of in vitro studies with sediment extracts. With respect to the ecological status of the Danube River, the results overall indicate a moderate to severe genotoxic potential with a highly differential localization.
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2.
  • Grund, Stefanie, et al. (författare)
  • Assessment of fish health status in the Upper Danube River by investigation of ultrastructural alterations in the liver of barbel Barbus barbus
  • 2010
  • Ingår i: Diseases of Aquatic Organisms. - Luhe, Germany : Inter-Research. - 0177-5103 .- 1616-1580. ; 23, s. 235-248
  • Tidskriftsartikel (refereegranskat)abstract
    • Despite intensive efforts and tightened guidelines for improvement of water quality over the last 2 decades, declines of fish populations have been reported for several rivers around the world. The present study forms part of a comprehensive weight-of-evidence approach, which aims to identify potential causes for the decline in fish catches observed in the Upper Danube River. The major focus of the present study is the investigation of the health status of wild barbel Barbus barbus L. collected from 3 locations along the Danube River, which experienced different levels of contamination. Whereas the comparison of the condition factor (CF) of field fish with that of control fish revealed no differences, ultrastructural investigations indicated severe disturbance of hepatic cell metabolism in field fish from the more contaminated sites Rottenacker and Ehingen, compared to both control fish and field fish from the less contaminated site Riedlingen. The ultrastructural analysis provided information about reactions of e.g. the rough endoplasmic reticulum, peroxisomes, andmitochondria, indicating an impaired health status of barbel at the sampling sites Rottenacker and Ehingen. Even though a straightforward cause-effect relationship between sediment contamination and ultrastructural alterations could not be established, based on a meta-analysis and toxicity assays it may be suggested that sediment-bound xenobiotics at least partly account for the hepatocellular changes. A relationship between impaired fish health status and the decline of fish catches along the Upper Danube River cannot be excluded.
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3.
  • Hettmer, Simone, et al. (författare)
  • Genetic testing and surveillance in infantile myofibromatosis : a report from the SIOPE Host Genome Working Group
  • 2021
  • Ingår i: Familial Cancer. - : Springer. - 1389-9600 .- 1573-7292. ; 20 SI:4, s. 327-336
  • Tidskriftsartikel (refereegranskat)abstract
    • Infantile myofibromatosis (IM), which is typically diagnosed in young children, comprises a wide clinical spectrum ranging from inconspicuous solitary soft tissue nodules to multiple disseminated tumors resulting in life-threatening complications. Familial IM follows an autosomal dominant mode of inheritance and is linked toPDGFRBgermline variants. SomaticPDGFRBvariants were also detected in solitary and multifocal IM lesions.PDGFRBvariants associated with IM constitutively activate PDGFRB kinase activity in the absence of its ligand. Germline variants have lower activating capabilities than somatic variants and, thus, require a second cis-acting hit for full receptor activation. Typically, these mutant receptors remain sensitive to tyrosine kinase inhibitors such as imatinib. The SIOPE Host Genome Working Group, consisting of pediatric oncologists, clinical geneticists and scientists, met in January 2020 to discuss recommendations for genetic testing and surveillance for patients who are diagnosed with IM or have a family history of IM/PDGFRBgermline variants. This report provides a brief review of the clinical manifestations and genetics of IM and summarizes our interdisciplinary recommendations.
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4.
  • Hollert, Henner, et al. (författare)
  • Eine Weight-of-Evidence-Studie zur Bewertung der Sedimentbelastung und des Fischrückgangs in der Oberen Donau [Assessing sediments and fish health using a weight-of-evidence approach : in search for the causes of fish decline in the Danube river]
  • 2009
  • Ingår i: Umweltwissenschaften und Schadstoff-Forschung. - Berlin : Springer. - 0934-3504 .- 1865-5084. ; 21:3, s. 260-263
  • Tidskriftsartikel (refereegranskat)abstract
    • Background and aim Despite intensive and continuous stocking and improvement of water quality since the 1970s, fish populations, especially those of the grayling (Thymallus thymallus), have declined over the last two decades in the upper Danube River (Germany). In order to assess 1) possible links between molecular/biochemical responses and ecologically relevant effects, and 2) if ecotoxicological effects might be related to the decline in fish catches in the upper Danube river, sediment samples and fish were collected at different locations and analyzed using a weight-of-evidence (WOE) approach with several lines of evidence. The objective of the presentation is to introduce the conceptual framework and to review results of the ongoing study. As previously addressed by Chapman and Hollert (2006) a variety of lines of evidence can be used in WOE studies. Briefly, 1) a comprehensive battery of acute and mechanism-specific bioassays was used to characterize the ecotoxicological hazard potential. 2) Histopathological investigations and the micronucleus assay with erythrocytes were applied, analyzing in situ parameters. 3) Diversity and abundance of benthic macroinvertebrates and fish as well as 4) persistent organic pollutants, endocrine disrupting substances, limnochemical parameters and the concentration of heavy metals were recorded. To identify organic contaminants a spotential causes of sediment toxicity assays, 5) effect directed analysis was applied. © 2009 Springer-Verlag.
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5.
  • Laakso, Ekaterina, et al. (författare)
  • Aging mechanisms of NMC811/Si-Graphite Li-ion batteries
  • 2024
  • Ingår i: Journal of Power Sources. - : Elsevier. - 0378-7753 .- 1873-2755. ; 599
  • Tidskriftsartikel (refereegranskat)abstract
    • Electrode degradation processes at various Li-ion batteries' state-of-health (SoH 100 %, 80 %, 50 %, and 30 %) and cycling temperatures (5°C, 23°C, and 45°C) were investigated. For this purpose, the standard format of Li-ion cylindrical 18,650 batteries with Si-Graphite negative and LiNi0⋅8Co0⋅1Mn0⋅1O2 (NMC811) positive electrodes were cycled with registering battery parameters and the electrochemical impedance spectrum were recorded after every 200 cycles. Once reaching their end-of-life, electrodes from cycled batteries were subjected to post-mortem analysis. NMC811 positive electrode was observed to crack during the charge and discharge processes, suffered by irreversible phase transition, transition metal dissolution, cathode electrolyte interphase growth, and cation mixing. The Si-Graphite negative electrode material was also affected by crack formation, layer exfoliation, solid electrolyte interphase (SEI) recompositing, Li dendrite growth, transition metal contamination, and Si dissolution. Degradation of components leads to an increase of the contact resistance, Li+ diffusion limitations, reduction of active materials participating in Li-ion storage and, as a result, capacity fade that finally rendered the battery utilization unfeasible. Degradation processes can be detected by capacity fade and impedance growth of the full battery. High temperature accelerates electrode degradation processes when low temperature leads to SEI and Li dendrite growth.
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6.
  • Mašláň, S, et al. (författare)
  • Interlaboratory comparison of battery impedance analyzers calibration
  • 2023
  • Ingår i: Measurement. - : Elsevier B.V.. - 0263-2241 .- 1873-412X. ; 218
  • Tidskriftsartikel (refereegranskat)abstract
    • The paper reports a results of series of interlaboratory comparisons of low impedance measurements at frequencies relevant for electrochemical impedance spectroscopy (EIS) of commercial lithium-ion cells. Two comparisons are presented. The first, bilateral comparison has focused on low impedance standards calibration in a full complex plane using digital sampling setups. The second comparison has focused on calibration and use of commercial 4-terminal battery EIS meters. Both comparisons have covered the impedance range from 50μ℧ to 100m℧ across the full complex plane in a frequency range from 0.01Hz up to 5kHz. Finally, the paper summarizes practices identified as critical for achieving measurement compatibility among various labs. © 2023 The Authors
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7.
  • Mašláň, Stanisalav, et al. (författare)
  • Interlaboratory Comparison of Low Impedance for Impedance Spectroscopy
  • 2022
  • Ingår i: 25th IMEKO TC-4 International Symposium on Measurement of Electrical Quantities, IMEKO TC-4 2022 and 23rd International Workshop on ADC and DAC Modelling and Testing, IWADC 2022. - : International Measurement Confederation (IMEKO). - 9781713862833 ; , s. 227-232
  • Konferensbidrag (refereegranskat)abstract
    • The paper reports an interlaboratory comparison of low impedance measurements at frequencies relevant for electrochemical impedance spectroscopy (EIS) of commercial lithium-ion cells. The comparisons cover an impedance range from 50 μΩ to 100 mΩ across the full complex plane in a frequency range 0.01 Hz up to 5 kHz. A first comparison covered calibration of low impedance standards by reference digital sampling impedance setups in 4-terminal and 4 terminal-pair connections. A second comparison used commercial 4-terminal EIS meters to measure the low impedance standards characterised in the first comparison.
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8.
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9.
  • Seitz, Nadja, et al. (författare)
  • A novel statistical approach for the evaluation of comet assay data
  • 2008
  • Ingår i: Mutation Research. - : Elsevier. - 1383-5742 .- 1388-2139. ; 652:1, s. 38-45
  • Tidskriftsartikel (refereegranskat)abstract
    • The present study forms part of a weight-of-evidence framework including genotoxicological studies in the upper Danube River basin, which aim at elucidating the reasons for the decline in fish catch. The major focus of this paper is the assessment of genotoxicity of sediments from the Danube River basin by use of the comet assay with RTL-W1 cells and with embryos of zebrafish (Danio rerio). A frequently discussed question in this type of approach is how to aggregate and compare the data obtained from genotoxicity testing. There is a need to develop mathematical method combining the information from dose–response curves and level of effectiveness (maximum genotoxic effect). For comparison and ranking of the genotoxic potential of samples from different locations along the Danube River, several methods based on EC50, Lowest Observed Effect Concentration (LOEC), and maximum induction factor were compared with respect to their validity. An evaluation system termed the “3-step, analysis” was developed to facilitate consideration of a maximum number of aspects of the raw data. The so-called “concentration-dependent induction factor” (CDI) introduces an index for a straightforward, precise and realistic assessment of the genotoxic potential of any kind of field sample or genotoxic agent.
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10.
  • Wittwer, Raphaël A., et al. (författare)
  • Organic and conservation agriculture promote ecosystem multifunctionality
  • 2021
  • Ingår i: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 7:34
  • Tidskriftsartikel (refereegranskat)abstract
    • Ecosystems provide multiple services to humans. However, agricultural systems are usually evaluated on their productivity and economic performance, and a systematic and quantitative assessment of the multifunctionality of agroecosystems including environmental services is missing. Using a long-term farming system experiment, we evaluated and compared the agronomic, economic, and ecological performance of the most widespread arable cropping systems in Europe: Organic, conservation, and conventional agriculture. We analyzed 43 agroecosystem properties and determined overall agroecosystem multifunctionality. We show that organic and conservation agriculture promoted ecosystem multifunctionality, especially by enhancing regulating and supporting services, including biodiversity preservation, soil and water quality, and climate mitigation. In contrast, conventional cropping showed reduced multifunctionality but delivered highest yield. Organic production resulted in higher economic performance, thanks to higher product prices and additional support payments. Our results demonstrate that different cropping systems provide opposing services, enforcing the productivity-environmental protection dilemma for agroecosystem functioning.
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