| 1. |
- Persson, Leif, et al.
(författare)
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Application of a Monte Carlo method to the uncertainty assessment in in situ gamma-ray spectrometry
- 2018
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Ingår i: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 187, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- In situ gamma-ray spectrometry has since the introduction of portable germanium detectors been a widely used method for the assessment of radionuclide ground deposition activity levels. It is, however, a method that is most often associated with fairly large and, more important, poorly known combined measurement uncertainties. In this work an uncertainty analysis of in situ gamma ray spectrometry in accordance with the Guide to the Expression of Uncertainty in Measurements is presented. The uncertainty analysis takes into account uncertainty contributions from the calibration of the detector system, the assumed activity distribution in soil, soil density, detector height and air density. As a result, measurement results from in situ gamma spectrometry will serve as a better basis for decision-making in e.g. radiological emergencies.
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| 2. |
- Jaric, Ivan, et al.
(författare)
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Insight into Danube sturgeon life history: trace element assessment in pectoral fin rays
- 2011
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Ingår i: Environmental Biology of Fishes. - : Springer Science and Business Media LLC. - 0378-1909 .- 1573-5133. ; 90:2, s. 171-181
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Tidskriftsartikel (refereegranskat)abstract
- Sturgeon populations in the Danube River have experienced severe decline during the last several decades, mostly due to the poorly regulated fishery, river fragmentation and water pollution. This study focuses on gaining better understanding of sturgeon life history primarily by addressing the assessment of microelement accumulation in sturgeon pectoral fin rays, especially of strontium and calcium, as a method that can reveal migration patterns of anadromous sturgeons. Analysis was performed on pectoral fin samples of three anadromous Danube sturgeon species (beluga, Russian sturgeon and stellate sturgeon) by the use of a Nuclear Microprobe technique. The most frequent pattern in analyzed samples was represented by a low Sr:Ca ratio in the innermost annuli, followed by an increased ratio in the middle annuli segment, and often with a decreased ratio in the outermost annuli. Probability density estimate has revealed three distinguished maxima of the Sr: Ca ratio, 7.08x10(-3), 8.98x10(-3) and 9.90x10(-3), which might correspond, respectively, to fresh, brackish and saltwater. Although the analysis of the Sr: Ca ratio in sturgeon pectoral fin rays has revealed changes that might indicate probable migration between habitats with different water salinity, further studies are needed for improvement of this method. This study represents the first analysis of this kind that was conducted on sturgeon species from the Black Sea basin.
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| 3. |
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Kärnavfallets politiska utmaningar
- 2005
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Samlingsverk (redaktörskap) (övrigt vetenskapligt/konstnärligt)abstract
- I den antika myten stjäl Prometeus elden från gudarna och ger den till människorna. Människorna får värme och kan tillverka ting som ökar deras välfärd. Som straff tas Prometeus till fånga av Zeus och kedjas fast högt uppe bland Kaukasus bergstoppar, där rovfåglar under trettiotusen år äter av hans lever. Det kulturella dilemma som kärnavfallet ställer oss inför är gammalt. Det som ger välfärd och framsteg är samtidigt hotfullt och ställer människan inför svåra avgöranden. Vi har tillägnat oss en energikälla som är förknippad med stora faror och hot om lidanden. Avfallet är farligt i sig, det har nära koppling till kärnvapenproduktion, på så sätt att upparbetning av avfallet ger upphov till rent plutonium. Den lösning som föreligger är att placera avfallet djupt ner i berget där det kan ligga säkert och utan fara för människor till dess radioaktiva strålning avklingat. Den tidsperiod under vilken faran består är lång, det räcker här inte med de trettiotusen år av lidande som Prometeus hade framför sig, utan om etthundratusen år. Den här antologin handlar om kärnavfallsfrågan - en samhällsfråga som är kontroversiell och får konsekvenser för politik och värderingar. Antologin försöker identifiera och precisera centrala utmaningar för den kommande hanteringen av kärnavfallet samt peka ut angelägna uppgifter för vidare forskning.
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| 4. |
- Limjiasahapong, Suphitcha, et al.
(författare)
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UPLC-ESI-MRM/MS for Absolute Quantification and MS/MS Structural Elucidation of Six Specialized Pyranonaphthoquinone Metabolites From Ventilago harmandiana
- 2021
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Ingår i: Frontiers in Plant Science. - : Frontiers Media SA. - 1664-462X. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Pyranonaphthoquinones (PNQs) are important structural scaffolds found in numerous natural products. Research interest in these specialized metabolites lies in their natural occurrence and therapeutic activities. Nonetheless, research progress has thus far been hindered by the lack of analytical standards and analytical methods for both qualitative and quantitative analysis. We report here that various parts of Ventilago harmandiana are rich sources of PNQs. We developed an ultraperformance liquid chromatography-electrospray ionization multiple reaction monitoring/mass spectrometry method to quantitatively determine six PNQs from leaves, root, bark, wood, and heartwood. The addition of standards in combination with a stable isotope of salicylic acid-D-6 was used to overcome the matrix effect with average recovery of 82% +/- 1% (n = 15). The highest concentration of the total PNQs was found in the root (11,902 mu g/g dry weight), whereas the lowest concentration was found in the leaves (28 mu g/g dry weight). Except for the root, PNQ-332 was found to be the major compound in all parts of V. harmandiana, accounting for similar to 48% of the total PNQs quantified in this study. However, PNQ-318A was the most abundant PNQ in the root sample, accounting for 27% of the total PNQs. Finally, we provide novel MS/MS spectra of the PNQs at different collision induction energies: 10, 20, and 40 eV (POS and NEG). For structural elucidation purposes, we propose complete MS/MS fragmentation pathways of PNQs using MS/MS spectra at collision energies of 20 and 40 eV. The MS/MS spectra along with our discussion on structural elucidation of these PNQs should be very useful to the natural products community to further exploring PNQs in V. harmandiana and various other sources.
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