| 1. |
- Grünfeld, Katrin, 1968-
(författare)
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Visualization, integration and analysis of multi-element geochemical data
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- generated large databases containing information on the concentrations of chemical elements in rocks, surface sediments and biogeochemical materials. Regional geochemical data being imprecise, multivariate, spatially auto-correlated and non-normally distributed pose specific problems to the choice of data analysis methods. Commonly several methods are combined, and the choice of techniques depends on the characteristics of data as well as the purpose of study. One critical issue is dealing with extreme data values (or outliers) in the initial stages of analysis. Another common problem is that integrated analysis of several geochemical datasets is not possible without interpolating the point data into surfaces. Finally, separation of anthropogenic influences from natural geochemical background in the surface materials is an issue of great importance for environmental studies. This study describes an approach to address the above-mentioned problems by a flexible combination and use of GIS and multivariate statistical techniques with high-dimensional visualization. Dynamically linked parallel coordinate and scatterplot matrix display techniques allow simultaneous presentation of spatial, multi-element and qualitative information components of geochemical data. The plots not only display data in multi-dimensional space, but also allow detailed inspection of the data with interactive multi-dimensional brushing tools. The results of the study indicate that these simple high-dimensional visualization techniques can successfully complement the traditional statistical and GIS analysis in all steps of data processing, from data description and outlier identification through data integration, analysis, validation, and presentation of results. The outcomes of the study include: a visual procedure towards intelligent data cleaning where potentially significant information in very high element concentrations is preserved, methods for integration and visual analysis of geochemical datasets collected in different grids, estimation of geochemical baseline concentrations of trace metals in till geochemistry of southeastern Sweden, use of multi-element spatial fingerprints to trace natural geochemical patterns in biogeochemistry, and a new graphical approach to present multi-element geochemical data summaries and results from numerical analysis.
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| 2. |
- Kaarniranta, Kai, et al.
(författare)
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Geldanamycin activates Hsp70 response and attenuates okadaic acid-induced cytotoxicity in human retinal pigment epithelial cells.
- 2005
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Ingår i: Brain Research. Molecular Brain Research. - : Elsevier. - 0169-328X .- 1872-6941. ; 137:1-2, s. 126-131
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Tidskriftsartikel (refereegranskat)abstract
- Reversible protein phosphorylation regulates the biological activities of many human proteins involved in crucial cellular processes, e.g., protein-protein interactions, cell signaling, gene transcription, cell growth, and death. A malfunction of cellular homeostasis in retinal pigment epithelial (RPE) cells is involved in the age-related retinal degeneration. In this study, we examined cytotoxicity in human RPE cells subjected to the protein phosphatase inhibitor, okadaic acid (OA). Moreover, the influence of Hsp90 inhibitor geldanamycin (GA), a benzoquinone ansamycin, in cytoprotection was assessed. Hsp70 protein levels were analyzed by Western blot. Cellular viability was determined by LDH and MTT assays. To study apoptotic cell death, caspase-3 enzyme activity was measured by assaying the cleavage of a fluorescent peptide substrate and Hoechst dye was used to visualize nuclear morphology. OA treatment caused morphological changes and induced cytotoxicity by caspase-3-independent manner in the RPE cells. No evidence of nuclear fragmentation was observed in response to OA. Interestingly, GA treatment accumulated Hsp70 protein and attenuated OA-induced cytotoxicity. This study suggests that Hsp70 and Hsp90 are closely related to cytoprotection of RPE cells in response to protein phosphatase inhibition.
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| 3. |
- Lax, Kaj
(författare)
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Biogeochemical data from SGU : properties and applications
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Geochemical mapping is a technique that has been used all over the world for a multitude of purposes. The biogeochemical mapping programme conducted by the Geological Survey of Sweden (SGU) is mainly based on stream plant chemistry, which, opposed to mapping based on inorganic stream sediments or soils, is a method that is very uncommon. The stream plants are roots of Carex species, roots of Filipendula ulmaria, and whole plant samples of Fontinalis antipyretica. Samples are collected at an average density of one sample per 7 km2. In urban areas, where access to naturally growing stream plants often is difficult or impossible, transplants of F. antipyretica are used. This thesis aims to increase understanding of some fundamental properties of the biogeochemical data set, and to describe some applications. The focus of the applications described is related to environmental issues, but these can to some degree be extended towards mineral exploration as well. Three important properties studied and described are 1) analytical quality of the data, 2) effects of expressing contents on a dry weight basis instead of as residuals, and 3) species dependent responses. It is shown that the analytical quality for most elements used are quite good, at least for the parameters further studied in the thesis. Species dependent responses do exist, but only for a few of the parameters is the influence strong enough to cause problems during interpretation. The most pronounced effect is a significant enrichment of Mn and Co in F. antipyretica as compared to the other species. Some effects can also be seen on Ba and Zn, but not to the same extent. Incidentally, the problem is somewhat less pronounced if the residual method of expressing concentrations is used. This residual method is based on stepwise regression, where Mn is one of the independent variables. For all other elements, expressing contents relative to dry weight could not be determined to cause any negative effects. As the dry weight basis is very commonly used for expressing concentrations, for most elements it can and should be used instead of the residuals historically used. One problem, that has proved to be difficult to solve, is the presence of variable amounts of minerogenic matter in the samples. However, as there are excellent correlations between several of the parameters (e g Ti, Cr, Al, Si, Zr) and loss on ignition, the other parameters can be used to aid interpretation. Chromium is one example, where unusually high Cr:Ti ratios occur at several locations with metallurgical or other industrial activities. Active acid sulphate (AS) soils is another example of anthropogenic contamination of the environment. The AS soils are quite common in areas below the highest shoreline in Finland and Sweden. It is however quite difficult to determine exactly where they are located. The thesis demonstrates that biogeochemical data provides information that can be used to localize such areas, where the stream water regularly is acidic and metal rich. Here again, a ratio (Y:Pb or Ni:Pb) can be used in order to further amplify the signature. Yttrium and Ni have been shown to occur in elevated levels in stream water affected by active AS soils, whereas Pb-concentrations even tend not to increase, or even decrease. In a selected drainage basin, it is shown that transplants of F. antipyretica responds fairly well to the stream water typical for AS soils. The F. antipyretica transplants as well as the other biological media studied, stair step moss (Hylocomium splendens), also contribute to demonstrating that the urban areas are geochemically complex, there is no straightforward relationship to the other sampling media studied. As in the other examples demonstrated above, baseline information from till and other soils provide a valuable key to understanding the biogeochemical data set.
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| 4. |
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| 5. |
- Salminen, Reijo, et al.
(författare)
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Environmental geology
- 2008
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Ingår i: Episodes. - : International Union of Geological Sciences. - 0705-3797 .- 2586-1298. ; 31:1, s. 155-162
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Tidskriftsartikel (refereegranskat)abstract
- The mining environment, medical geology and urban geochemistry form a group of related scientific disciplines that have developed strongly during recent years in the Nordic countries. Modern legislation controls the environmental issues. Close co-operation of researchers and legislators has improved the quality and safety of life in the societies of the Nordic countries. In mining environmental studies, methods that are suitable in Arctic conditions have been developed; in medical geology, the input from the Nordic countries has made it an appreciated scientific discipline throughout the world, and in the case of the urban environment, methods developed by our geochemists have especially improved the health conditions, particularly of children.
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| 6. |
- Åström, Mats E., et al.
(författare)
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Uranium in surface and ground waters in Boreal Europe
- 2009
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Ingår i: Geochemistry. - : Geological Society of London. - 1467-7873 .- 2041-4943. ; 9, s. 51-62
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Tidskriftsartikel (refereegranskat)abstract
- This study focuses on uranium (U) in surface and groundwaters in Boreal Europe (Sweden, Finland, Russia). Data from recently completed regional hydrogeochemical surveys and from site-specific studies were combined, in order to enhance the current understanding of U behaviour in the catchments and water bodies of these northerly latitudes. Over Precambrian areas (dominated by igneous and metamorphic rocks) the aqueous U concentrations in general increased in a downward direction, i.e. from stream waters to overburden groundwaters to bedrock groundwaters, and they were correlated with the U abundance in the surrounding overburden (mainly glacial till). Over Phanerozoic areas (dominated by terrigene deposits containing or composed of limestone) the aqueous U concentrations were, in contrast, unrelated to overburden U concentrations and strongly correlated with dissolved Ca and HCO(3) concentrations. There is thus an overall geochemical and hydrochemical control, respectively, related to the underlying lithology. At geologically specific and local sites there is a range of correlations and control mechanisms of aqueous U. From acid sulphate soils, occurring abundantly on coastal plains, runoff below pH 4.0 is enriched in U (up to 55 mu g/l) most likely due to oxidation of U(IV) minerals followed by subsequent limited sorption of U(VI) in the acidic environment. In a studied black shale setting, characterized by high U concentrations (LIP to > 200 ppm), U levels increased in groundwater (up to 200 mu g/l) and surface water (up to 80 mu g/l) as the conditions changed from reducing to oxidizing. In an unmineralized granitic setting, proposed as a repository for spent nuclear fuel, elevated U concentrations in surface waters (up to 25 mu g/l) reflect a regional stream-hydrochemical anomaly and in bedrock groundwaters (up to > 100 mu g/l), most likely mobilization of uranyl from U-rich fracture coatings. In the Baltic Sea, which has unique brackish water, the ratio of U to Cl is similar to that in the oceans but contrasting near-coastal U trends exist, characterized by all inverse relationship between IT and Cl concentrations. These coastal-water anomalies are most likely caused by high U levels in inflowing streams, and possibly to some extent submarine discharge of U-enriched waters.
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