| 1. |
- Carlsson, J, et al.
(författare)
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Kin-biased distribution in brown trout : an effect of redd location or kin recognition?
- 2004
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Ingår i: Heredity. - : Springer Science and Business Media LLC. - 0018-067X .- 1365-2540. ; 92:2, s. 53-60
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Tidskriftsartikel (refereegranskat)abstract
- A wide range of animals have been reported to show kin-biased behaviours, such as reduced aggressiveness and increased food sharing among relatives. However, less is known about whether wild animals also associate with relatives under natural conditions, which is a prerequisite to facilitate kin-biased behaviours and hence kin selection. We tested, by means of microsatellite polymorphism, correlations between pair-wise relatedness and pair-wise metric distance in wild brown trout ( Salmo trutta L.) under natural conditions in two streams. Our data show that young-of-the-year as well as older trout found close together also had a higher genetic relatedness in one of the two streams, whereas no relationship was found in the other stream. Very few half and full siblings were found in the second stream and under these conditions it is unlikely that kin-biased behaviours will receive positive selection. We discuss the underlying mechanisms for the observed structure and we specifically address the issue of whether the grouping of related individuals could reflect dispersal from the same spawning redds, or if it reflects active association with relatives, possibly conferring kin-selected advantages.
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| 2. |
- Eriksson, Johan, Professor, 1967-, et al.
(författare)
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Outsourcing the American Space Dream : SpaceX and the Race to the Stars
- 2023
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Ingår i: Astropolitics. - : Taylor & Francis Group. - 1477-7622 .- 1557-2943. ; 21:1, s. 46-62
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Tidskriftsartikel (refereegranskat)abstract
- Whereas the rise of private space entrepreneurship is indisputable, we contend that contrary to the “NewSpace” narrative, the development of privately owned and operated human spacefaring does not dispel or fundamentally alter the American space dream, but rather implies continuity of the narrative of America as the dominant global space power, specifically regarding a return to the Moon and with the explicit aim of colonizing Mars. Herein, we analyze the continuity of the American space dream and how it is expressed by public and private space actors, as well as being supported by popular culture, entertainment, and an active space enthusiast community. We maintain that the continuity of the American space dream as a unifying national narrative is facilitated by how private spacefaring is dependent on the U.S. Government’s emphasis on the pivotal role of private space industry for space exploration. This dependent relationship provides incentives for private space entrepreneurs to share and leverage the established American space dream. The continuity of the American space dream is achieved through a prevailing, yet reconfigured, government-industrial complex.
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| 3. |
- Eriksson, Johan, Professor, 1967-, et al.
(författare)
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Theorizing Technology in International Relations : Prevailing Perspectives and New Horizons
- 2021
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Ingår i: Technology and International Relations. - Cheltenham : Edward Elgar Publishing. - 9781788976060 ; , s. 1-21
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Bokkapitel (refereegranskat)abstract
- This chapter presents an introduction to and brief overview of the study of technology and international relations, including a discussion of research gaps and new horizons. In particular, this contribution addresses whether and how prevailing theoretical approaches have been able to analyze the relationship between technological and international political change. This includes how the personal, social, societal, and, to an extent, also biological worlds are becoming increasingly interconnected through new technologies – what has been referred to as the ‘fourth industrial revolution’ (Newlove-Eriksson and Eriksson, 2021; Schwab, 2017). How then is technology addressed within the field of international relations (IR)? Given the considerable attention IR literature pays to globalization and global structural change – core themes of contemporary IR – it might be expected that the role of technology in world politics would be a major focus. What would global politics and globalization be if the rapid development and diffusion of global information and communications technologies (ICTs) were not taken into account? It would seem, nonetheless, that technology has received rather mixed and selective attention within IR.
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| 4. |
- Rissler, P., et al.
(författare)
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Adriamycin cytotoxicity may stimulate growth of hepatocellular tumours in an experimental model for adjuvant systemic chemotherapy in liver transplantation
- 2005
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Ingår i: Transplant International. - : Frontiers Media SA. - 0934-0874 .- 1432-2277. ; 18:8, s. 992-1000
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Tidskriftsartikel (refereegranskat)abstract
- Adjuvant treatment with adriamycin has been suggested to improve results after liver transplantation for hepatocellular cancer. Here we have applied an animal model for evaluation of treatment with adriamycin and/or cyclosporine A on liver tumour growth. Three chemically induced rat liver tumours with various degree of differentiation were transferred to the spleens of syngenic rats. Each recipient group was divided into four subgroups, treated with adriamycin and/or cyclosporine A or none of the drugs. When the tumour was well differentiated no proliferation was found in any of the subgroups. When the tumour exhibited a more pronounced dysplasia, adriamycin stimulated tumour growth. This effect was further increased by cyclosporine. In the animals transplanted with the most aggressive tumour, adriamycin inhibited tumour growth. When given together with cyclosporine this inhibition was counteracted. These data suggest that adriamycin, especially when given together with cyclosporine, may have a stimulatory effect on liver tumour cell growth.
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| 5. |
- Xia, Ling, et al.
(författare)
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Reduction of ubiquinone by lipoamide dehydrogenase : An antioxidant regenerating pathway
- 2001
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Ingår i: European Journal of Biochemistry. - : Wiley. - 0014-2956 .- 1432-1033. ; 268:5, s. 1486-1490
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Tidskriftsartikel (refereegranskat)abstract
- Lipoamide dehydrogenase belongs to a family of pyridine nucleotide disulfide oxidoreductases and is ubiquitous in aerobic organisms. This enzyme also reduces ubiquinone (the only endogenously synthesized lipid-soluble antioxidant) to ubiquinol, the form in which it functions as an antioxidant. The reduction of ubiquinone was linear with time and exhibited turnover numbers of 5 and 1.2 min-1 in the presence and absence of zinc, respectively. The reaction was stimulated by zinc and cadmium but not by the other divalent ions tested. The zinc/cadmium-dependent stimulation of the reaction increased rapidly and linearly up to a concentration of 0.1 mM and was even further increased at 0.5 mM. At pH 6, the activity was three times higher than at physiological pH. Alteration of the NADPH : NADP+ ratio revealed that the reaction is inhibited by higher concentrations of the oxidized cofactors. FAD reduced ubiquinone in a dose-dependent manner at a considerably lower rate, suggesting that the reduction of ubiquinone by lipoamide dehydrogenase involves the FAD moiety of the enzyme.
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| 6. |
- Belyaev, I Y, et al.
(författare)
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Effects of ethidium bromide on DNA loop organisation in human lymphocytes measured by anomalous viscosity time dependence and single cell gel electrophoresis
- 1999
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Ingår i: Biochimica et Biophysica Acta - General Subjects. - 0304-4165 .- 1872-8006. ; 1428:2-3, s. 348-356
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Tidskriftsartikel (refereegranskat)abstract
- The effects of ethidium bromide (EtBr) on human lymphocytes were studied by the method of anomalous viscosity time dependence (AVTD) and by the comet assay. EtBr at low concentrations increased the maximum viscosity and time of radial migration as measured with AVTD at neutral conditions of lysis. A pronounced relaxation of DNA loops was observed with the neutral comet assay. The maximal comet length corresponded to 2 Mb DNA loops. At high concentrations of EtBr, 2. mg/ml, significant reduction in AVTD below control level was seen that suggested hypercondensation of chromatin. The hypercondensation was directly observed with the neutral comet assay. EtBr did not induce DNA strand breaks as measured by the alkaline comet assay. The hypercondensed nuclei could be decondensed by irradiation with gamma-rays or exposure to light. The data provide evidence that EtBr at high concentrations resulted in hypercondensation of chromatin below control level. The comet assay confirmed that the increase in AVTD peaks deals with relaxation of loops and AVTD decrease is caused by chromatin condensation. The prediction of the AVTD theory for a correlation between time of radial migration and condensation of chromatin was verified. Further, the data show that the comet assay at neutral conditions of lysis is rather sensitive to DNA loop relaxation in the absence of DNA damage. Finally, donor specificity was found for the hypercondensation.
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| 7. |
- Eriksson, M., et al.
(författare)
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Well salinization risk and effects of Baltic Sea level rise on the groundwater-dependent Island of Öland, Sweden
- 2018
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Ingår i: Water. - : MDPI. - 2073-4441. ; 10:2
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we estimate baseline conditions in terms of the current risk of well salinization on the Baltic Sea island of öland, Sweden, and assess the effects of future sea level rise on the land area, infrastructure and cultural values. We use a multicriterion geographical information systems (GIS) approach. Geomorphological and physical parameters affect the risk of saltwater intrusion into freshwater aquifers, including their hydrology, geomorphology, and climatology; the spatial distribution of the current risk of salinization is mapped in this study. In the event of a future 2 m sea level rise, a total land area of 67 km2 will be inundated on öland, corresponding to approximately 5% of the island's land surface. Inundation includes urban areas, nature reserves, and animal protection areas, implying the loss of environmental and socioeconomic values. A future 2 m sea level rise will also cause direct inundation of 3% of all wells on the island. Currently, 17.5% of all wells are at a high risk of becoming saltwater contaminated. More generally, the present results add evidence showing a relatively high vulnerability of major Baltic Sea islands and their infrastructure to future sea level rise. The approach used here and related results, including salinization risk maps, may prove useful for decision-makers in the planning of infrastructure. Drilling of new wells could for instance preferably be done in areas with identified lower risk-index values, which would facilitate an overall higher freshwater withdrawal in the interest of the entire island. © 2018 by the authors.
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| 8. |
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| 9. |
- Xia, Ling, et al.
(författare)
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The mammalian cytosolic selenoenzyme thioredoxin reductase reduces ubiquinone. A novel mechanism for defense against oxidative stress
- 2003
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Ingår i: Journal of Biological Chemistry. - : American Society for Biochemistry and Molecular Biology. - 0021-9258 .- 1083-351X. ; 278:4, s. 2141-2146
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Tidskriftsartikel (refereegranskat)abstract
- The selenoprotein thioredoxin reductase (TrxR1) is an essential antioxidant enzyme known to reduce many compounds in addition to thioredoxin, its principle protein substrate. Here we found that TrxR1 reduced ubiquinone-10 and thereby regenerated the antioxidant ubiquinol-10 (Q10), which is important for protection against lipid and protein peroxidation. The reduction was time- and dose-dependent, with an apparent K(m) of 22 microm and a maximal rate of about 12 nmol of reduced Q10 per milligram of TrxR1 per minute. TrxR1 reduced ubiquinone maximally at a physiological pH of 7.5 at similar rates using either NADPH or NADH as cofactors. The reduction of Q10 by mammalian TrxR1 was selenium dependent as revealed by comparison with Escherichia coli TrxR or selenium-deprived mutant and truncated mammalian TrxR forms. In addition, the rate of reduction of ubiquinone was significantly higher in homogenates from human embryo kidney 293 cells stably overexpressing thioredoxin reductase and was induced along with increasing cytosolic TrxR activity after the addition of selenite to the culture medium. These data demonstrate that the selenoenzyme thioredoxin reductase is an important selenium-dependent ubiquinone reductase and can explain how selenium and ubiquinone, by a combined action, may protect the cell from oxidative damage.
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| 10. |
- Zhang, X P, et al.
(författare)
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Mutagenesis and computer modelling approach to study determinants for recognition of signal peptides by the mitochondrial processing peptidase
- 2001
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Ingår i: The Plant Journal. - 0960-7412 .- 1365-313X. ; 27:5, s. 427-438
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Tidskriftsartikel (refereegranskat)abstract
- Determinants for the recognition of a mitochondrial presequence by the mitochondrial processing peptidase (MPP) have been investigated using mutagenesis and bioinformatics approaches. All plant mitochondrial presequences with a cleavage site that was confirmed by experimental studies can be grouped into three classes. Two major classes contain an arginine residue at position -2 or -3, and the third class does not have any conserved arginines. Sequence logos revealed loosely conserved cleavage motifs for the first two classes but no significant amino acid conservation for the third class. Investigation of processing determinants for a class III precursor, Nicotiana plumbaginifolia F(1)beta precursor of ATP synthase (pF(1)beta), was performed using a series of pF(1)beta presequence mutants and mutant presequence peptides derived from the C-terminal portion of the presequence. Replacement of -2 Gln by Arg inhibited processing, whereas replacement of either the most proximally located -5 Arg or -15 Arg by Leu had only a low inhibitory effect. The C-terminal portion of the pF(1)beta presequence forms a helix-turn-helix structure. Mutations disturbing or prolonging the helical element upstream of the cleavage site inhibited processing significantly. Structural models of potato MPP and the C-terminal pF(1)beta presequence peptide were built by homology modelling and empirical conformational energy search methods, respectively. Molecular docking of the pF(1)beta presequence peptide to the MPP model suggested binding of the peptide to the negatively charged binding cleft formed by the alpha -MPP and beta -MPP subunits in close proximity to the H111XXE114H115X(116-190)E191 proteolytic active site on beta -MPP. Our results show for the first time that the amino acid at the -2 position, even if not an arginine, as well as structural properties of the C-terminal portion of the presequence are important determinants for the processing of a class III precursor by MPP.
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