| 1. |
- Andersson, Agneta, et al.
(författare)
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Projected future climate change and Baltic Sea ecosystem management
- 2015
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Ingår i: Ambio. - : Springer. - 0044-7447 .- 1654-7209. ; 44:Supplement 3, s. S345-S356
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Tidskriftsartikel (refereegranskat)abstract
- Climate change is likely to have large effects on the Baltic Sea ecosystem. Simulations indicate 2-4 degrees C warming and 50-80 % decrease in ice cover by 2100. Precipitation may increase similar to 30 % in the north, causing increased land runoff of allochthonous organic matter (AOM) and organic pollutants and decreased salinity. Coupled physical-biogeochemical models indicate that, in the south, bottom-water anoxia may spread, reducing cod recruitment and increasing sediment phosphorus release, thus promoting cyanobacterial blooms. In the north, heterotrophic bacteria will be favored by AOM, while phytoplankton production may be reduced. Extra trophic levels in the food web may increase energy losses and consequently reduce fish production. Future management of the Baltic Sea must consider the effects of climate change on the ecosystem dynamics and functions, as well as the effects of anthropogenic nutrient and pollutant load. Monitoring should have a holistic approach, encompassing both autotrophic (phytoplankton) and heterotrophic (e.g., bacterial) processes.
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| 2. |
- Andersson, Patrik, et al.
(författare)
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The internal barriers of rotation for the 209 polychlorinated biphenyls
- 1997
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Ingår i: Environmental Science and Pollution Research. - 0944-1344 .- 1614-7499. ; 4:2, s. 75-81
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Tidskriftsartikel (refereegranskat)abstract
- The internal barrier of rotation (Erot) was calculated for all 209 polychlorinated biphenyls (PCBs) by using a semi-empirical method, viz. the Austin Model 1 (AM1) Hamiltonian. The difference in total energy between a forced planar state and an optimised twisted structure was defined as Erot. The Erot values were in the range of 8.33 to 483 kJ/mol, and were significantly influenced by the number of chlorine atoms in ortho position. An additional structural characteristic of the PCBs influencing Erot of ortho substituted congeners was substitution by chlorine atoms in vicinal meta positions, which is assumed to prevent outward bending of ortho substituents. This so-called buttressing effect contributed with 4 to 31 kJ/mol per added chlorine atom. In conclusion, the internal barrier of rotation, calculated for all 209 PCBs, provides an important structure dependent physico-chemical parameter for multivariate modelling of future quantitative structure-activity and structure-property relationships (QSARs/QSPRs).
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| 3. |
- Andersson, Patrik, et al.
(författare)
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Ultraviolet absorption characteristics and calculated semi-empirical parameters as chemical descriptors in multivariate modelling of polychlorinated biphenyls
- 1996
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Ingår i: Journal of Chemometrics. - 0886-9383 .- 1099-128X. ; 10:2, s. 171-185
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Tidskriftsartikel (refereegranskat)abstract
- The structural variation within the polychlorinated biphenyls (PCBs) was characterized by using principal component analysis (PCA). A multivariate model was evolved from 52 physicochemical descriptors including measured ultraviolet (UV) absorption spectra, calculated semiempirical parameters (AM1) and properties captured from the literature. Parameters calculated by using the AM1-Hamiltonian were e.g. heat of formation, dipole moments, ionization potential and the barrier of internal rotation. The UV spectra were measured and digitized in the range 200-300 nm. The multivariate model revealed that most of the information within the set of physicochemical parameters was related to molecular size. Descriptors depending on size were e.g. GC retention times, partition coefficients and a subset of semiempirically derived energy terms. Important also were parameters reflecting differences in substitution patterns and related to electronic and steric properties, such as UV absorption in the wavelength region 245-300 nm, the barrier of internal rotation and the ionization potential. The developed model describes the large variation in physicochemical characteristics within the PCBs. The importance of a broad chemical characterization is illustrated by a quantitative structure-activity relationship (QSAR) for the potency of inhibition of intercellular communication for 27 structurally diverse tetra- to heptachlorinated PCBs.
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| 4. |
- Andersson, Patrik, et al.
(författare)
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Ultraviolet absorption spectra of all 209 polychlorinated biphenyls evaluated by principal component analysis
- 1997
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Ingår i: Fresenius' Journal of Analytical Chemistry. - : Springer Science and Business Media LLC. - 0937-0633 .- 1432-1130. ; 357:8, s. 1088-1092
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Tidskriftsartikel (refereegranskat)abstract
- The ultraviolet absorption spectra of all 209 polychlorinated biphenyls (PCBs) were recorded in the range 200-300 nm and displayed two important absorption maxima, viz., the main-band, lambda(max) 200-225 nm, and the kappa-band, lambda(max) 245-265 nm. By utilising principal component analysis, substitution related spectral characteristics of the PCBs, underlying the main patterns of the spectra, were examined. Captured in the multivariate evaluation were e.g., the importance of chlorine atoms in ortho positions, determining the intensity and existence of the kappa-band, chlorine substitution in para-para position, and the total number of chlorine atoms. The measured UV-spectra of all 209 polychlorinated biphenyls provide important physico-chemical descriptors for use in future quantitative structure-activity and structure-property relationship (QSAR/QSPR) studies.
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| 5. |
- Asghar, Naveed, et al.
(författare)
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Tick-borne encephalitis virus sequenced directly from questing and blood-feeding ticks reveals quasispecies variance.
- 2014
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Ingår i: PLOS ONE. - San Francisco, USA : Public Library of Science (PLoS). - 1932-6203. ; 9:7
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Tidskriftsartikel (refereegranskat)abstract
- The increased distribution of the tick-borne encephalitis virus (TBEV) in Scandinavia highlights the importance of characterizing novel sequences within the natural foci. In this study, two TBEV strains: the Norwegian Mandal 2009 (questing nymphs pool) and the Swedish Saringe 2009 (blood-fed nymph) were sequenced and phylogenetically characterized. Interestingly, the sequence of Mandal 2009 revealed the shorter form of the TBEV genome, similar to the highly virulent Hypr strain, within the 3' non-coding region (3'NCR). A different genomic structure was found in the 3'NCR of Saringe 2009, as in-depth analysis demonstrated TBEV variants with different lengths within the poly(A) tract. This shows that TBEV quasispecies exists in nature and indicates a putative shift in the quasispecies pool when the virus switches between invertebrate and vertebrate environments. This prompted us to further sequence and analyze the 3'NCRs of additional Scandinavian TBEV strains and control strains, Hypr and Neudoerfl. Toro 2003 and Habo 2011 contained mainly a short (A)3C(A)6 poly(A) tract. A similar pattern was observed for the human TBEV isolates 1993/783 and 1991/4944; however, one clone of 1991/4944 contained an (A)3C(A)11 poly(A) sequence, demonstrating that quasispecies with longer poly(A) could be present in human isolates. Neudoerfl has previously been reported to contain a poly(A) region, but to our surprise the re-sequenced genome contained two major quasispecies variants, both lacking the poly(A) tract. We speculate that the observed differences are important factors for the understanding of virulence, spread, and control of the TBEV.
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| 6. |
- Berggren, Mats, et al.
(författare)
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Kärnkraftsdebatt ger möjlighet till kritiskt tänkande i högstadiefysiken
- 2019
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Ingår i: Naturvetenskapernas och teknikens didaktik. - Linköping : LiU-Tryck. - 9789176850442 ; , s. 39-48
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- I skolans styrdokument betonas vikten av att elever ges möjlighet att utveckla sitt kritiska tänkande. Detta är inte minst angeläget i dessa tider av tillgång till sociala medier och spridande av så kallade alternativa fakta. Trots sin positiva klang finns det dock ingen etablerad konsensus kring vad kritiskt tänkande egentligen är. Inom ramen för ett skolutvecklingsprojekt i samverkan mellan Uppsala universitet och Tiundaskolan, en 4-9-skola i Uppsala, utforskar vi hur kritiskt tänkande kan uttryckas i undervisningspraktiken i ämnena svenska, historia, matematik och fysik. Som exempel har vi i fysikämnet designat, genomfört och analyserat en undervisningssekvens utifrån kärnkraft som tema, där elever i årskurs 9 gavs möjlighet att anamma olika åsikter och argument i frågan genom rollspel. Eleverna genomförde en debatt, där de representerade olika parter: boende nära Forsmark, miljöorganisationen Grön Fred, och företag som utvecklar kärnkraft, respektive vindkraft. Före och efter debatten skrev eleverna individuella texter där de argumenterade för sin personliga åsikt i frågan: Ska kärnkraften bevaras som den är, läggas ner, eller utvecklas? Vi fann att de genom debatten fick goda möjligheter att utveckla och visa kunskaper motsvarande flera kunskapskrav i kursplanen i fysik som annars sällan berörs i fysikklassrummet, såsom, för betyg A: ”Eleven kan samtala om och diskutera frågor som rör energi, teknik, miljö och samhälle och skiljer då fakta från värderingar och formulerar ställningstaganden med välutvecklade motiveringar samt beskriver några tänkbara konsekvenser.” Som exempel på naturvetenskapligt förankrade argument utnyttjade eleverna genererad energi per utsläppt mängd koldioxid som ett mått vid jämförelser mellan kärnkraft och andra energikällor. I de individuella texterna höll de flesta eleverna fast vid sina åsikter från innan de arbetade med temat även efteråt, men nu med fler och mer nyanserade argument.
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| 7. |
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| 8. |
- Bergknut, Magnus, et al.
(författare)
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Assessment of the availability of polycyclic aromatic hydrocarbons from gasworks soil using different extraction solvents and techniques
- 2004
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Ingår i: Environmental Toxicology and Chemistry. - : Wiley. - 0730-7268 .- 1552-8618. ; 23:8, s. 1861-1866
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Tidskriftsartikel (refereegranskat)abstract
- This study was designed to assess the availability of polycyclic aromatic hydrocarbons (PAHs) present at a gasworks site to different soil remediation techniques. The study examined the effect on PAH availability of using different organic solvents, the degree of pretreatment, and the extraction time. In total, 25 PAHs (with two to six fused rings) and five carbonyl derivatives were measured. The results indicated that the PAHs and their derivatives were bound loosely to the surface of the studied soil and that there were no significant kinetic boundaries associated with the extraction of the PAHs. Furthermore, it was concluded that the studied soil was not suitable for bioremediation, as the concentration of PAHs with low molecular weight were limited. However, pressurized liquid extraction (PLE) with methanol as the solvent extracted 97% of all PAHs and PAH-derivatives, indicating that extraction may be effective as part of a soil remediation technique for old gasworks soils.
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| 9. |
- Bergknut, Magnus, et al.
(författare)
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Characterization and classification of complex PAH samples using GC-qMS and GC-TOFMS
- 2006
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 65:11, s. 2208-2215
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to compare the polycyclic aromatic hydrocarbon (PAH) contents in a number of complex samples, including soil samples from industrial sites, anti-skid sand, urban dust and ash samples from municipal solid waste incinerators. The samples were characterized by routine analysis of PAHs (gas chromatography–quadrupole mass spectrometry) and gas chromatography–time of flight mass spectrometry (GC–TOFMS). Classification of the samples by principal component analysis (PCA) according to their composition of PAHs revealed that samples associated with traffic and the municipal incinerator formed homogeneous clusters, while the PAH-contaminated soils clustered in separate groups. Using spectral data to resolve co-eluting chromatographic peaks, 962 peaks could be identified in the GC–TOFMS analysis of a pooled sample and 123–527 peaks in the individual samples. Many of the studied extracts included a unique set of chemicals, indicating that they had a much more diverse contamination profile than their PAH contents suggested. Compared to routine analysis, GC–TOFMS provided more detailed information about each sample and in this study a large number of alkylated PAHs were found to be associated with the corresponding unsubstituted PAHs. The possibility to filter peaks according to different criteria (e.g. to include only peaks that were detected in the analysis of another sample) was explored and used to identify unique as well as common compounds within samples. This procedure could prove to be valuable for obtaining relevant chemical data for use in conjunction with results from various biological test systems.
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| 10. |
- Bergknut, Magnus, et al.
(författare)
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Comparison of techniques for estimating PAH bioavailability : uptake in Eisenia fetida, passive samplers and leaching using various solvents and additives.
- 2007
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Ingår i: Environmental Pollution. - : Elsevier BV. - 0269-7491 .- 1873-6424. ; 145:1, s. 154-60
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to evaluate different techniques for assessing the availability of polycyclic aromatic hydrocarbons (PAHs) in soil. This was done by comparing the amounts (total and relative) taken up by the earthworm Eisenia fetida with the amounts extracted by solid-phase microextraction (SPME), semi-permeable membrane devices (SPMDs), leaching with various solvent mixtures, leaching using additives, and sequential leaching. Bioconcentration factors of PAHs in the earthworms based on equilibrium partitioning theory resulted in poor correlations to observed values. This was most notable for PAHs with high concentrations in the studied soil. Evaluation by principal component analysis (PCA) showed distinct differences between the evaluated techniques and, generally, there were larger proportions of carcinogenic PAHs (4–6 fused rings) in the earthworms. These results suggest that it may be difficult to develop a chemical method that is capable of mimicking biological uptake, and thus estimating the bioavailability of PAHs. The total and relative amounts of PAHs extracted by abiotic techniques for assessing the bioavailability of PAHs was found to differ from the amounts taken up by Eisenia fetida. Keywords: Bioavailability; Polycyclic aromatic hydrocarbons; Earthworms; Leaching; Hydroxypropyl-β-cyclodextrin; Solid-phase microextraction; Semi-permeable membrane device
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