| 1. |
- Kraft, T., et al.
(författare)
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Positive correlation between recombination rates and levels of genetic variation in natural populations of sea beet (Beta vulgaris subsp. maritima)
- 1998
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Ingår i: Genetics. - 0016-6731 .- 1943-2631. ; 150:3, s. 1239-1244
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Tidskriftsartikel (refereegranskat)abstract
- The relation between the level of genetic variation and the rate of recombination per physical unit was investigated in sea beet (Beta vulgaris subsp. maritima). The rate of recombination per physical unit was estimated indirectly through marker density in an RFLP linkage map of sugar beet. From this map, we also selected RFLP markers covering two of the nine chromosomes in Beta. The markers were used to estimate the level of genetic variation in three populations of sea beet, two from Italy and one from England. Two estimates of genetic variation were employed, one based on the number of alleles in the sample and the other on heterozygosity. A statistically significant positive correlation was found between recombination rate and genetic variation. Several theoretical explanations for this are discussed, background selection being one. A correlation similar to this has been observed previously in Drosophila, one that was higher than what we obtained for Beta. This is consistent with various biological differences between the two species.
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| 2. |
- Magnusson, Christer, 1959-
(författare)
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Hedging shareholder value in an IT dependent business society : the framework BRITS
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Business Requirements on IT Security (BRITS) is a framework that can assist IT dependent companies to hedge losses due to IT-perils financially. Using BRITS can help these companies to hedge IT perils in the same professional way as consequences of traditional perils like fire, flood, robbery are hedged and thereby secure shareholders' investments.In the framework, the need for financial hedges and technical countermeasures against IT perils depends solely on the effect IT perils may have on the market value of the company; there are no other reasons for a commercial company to spend any of its resources on financial protection and IT security measures.BRITS has utilized and developed existing financial hedge instruments to provide cover against financial consequences of IT perils. To be able to use these instruments, I have developed a tool that can interpret and convert financial loss exposures into IT security measures, and vice versa; it is a knowledge gateway between financial and security terminology.The framework can, at least to some extent, make it possible to estimate the security awareness in existing IT-platforms. Based on that information, existing security measures can be "priced" as they may reduce the estimated maximum loss figures - and thereby the costs for the financial hedges.Moreover, more cost-effective decisions can be made on additional IT-security measures. In addition, the IT systems and the IT security's importance in the business processes can be understood more easily. Finally, the costs for the damage exposure inherent in companies' business services or products can be estimated in a better way, and thereby be incorporated in the products' price.
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| 3. |
- Wagner, Matthias, 1969-, et al.
(författare)
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Zeeman spectroscopy of the neutral silicon vacancy in 6H and 4H SiC
- 1999
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Ingår i: Physica B. Vol. 273-274. - : Elsevier. ; , s. 663-
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Konferensbidrag (refereegranskat)abstract
- High-resolution photoluminescence (PL) and PL excitation (PLE) spectroscopy has been employed to reveal the electronic structure of the neutral silicon vacancy in 6H and 4H SiC. The defect gives rise to characteristic PL emissions with three no-phonon lines in 6H SiC and two in 4H SiC at around 1.4 eV. All of the no-phonon lines are shown to arise from transitions between singlet (S=0) excited states and singlet ground states. Nevertheless, optically detected magnetic resonance (ODMR) signals typical for a spin triplet (S=1) configuration can be obtained when monitoring the emission under resonant excitation. This observation can be explained by non-radiative recombination via a lower lying excited triplet state. In strained samples all no-phonon PL lines are split into a series of lines. For the highest energy lines the main splitting can be attributed to lifting of the orbital degeneracy of the excited states, the additional broadening or splitting is probably due to a strain distribution in the samples.
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| 4. |
- Wingren, Christer, et al.
(författare)
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Antigen-binding sites dominate the surface properties of IgG antibodies
- 1995
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Ingår i: Molecular Immunology. - 1872-9142 .- 0161-5890. ; 32:11, s. 819-827
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Tidskriftsartikel (refereegranskat)abstract
- A new technique, liquid-liquid partition chromatography in an aqueous polyethylene glycol-dextran two-phase system, was used to detect differences in surface properties of antibodies with different antigen-binding sites. Employing well-characterized monoclonal IgG antibodies and Fab and Fc fragments thereof as well as chimeric IgG antibodies we found a remarkable relationship between structure of the antibody combining site and chromatographic behaviour. The surface properties of the IgG antibodies were dominated by those of its antigen-binding regions. In addition, our results indicated that the constant parts of the IgGs form similar scaffoldings, on to which CDRs of variable shapes and sizes are interspaced and constitute the major dominant differences in exposed surface properties.
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| 5. |
- Wingren, Christer, et al.
(författare)
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Comparison of Surface Properties of Human IgA, IgE, IgG and IgM Antibodies with Identical and Different Specificities
- 1996
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Ingår i: Scandinavian Journal of Immunology. - : Wiley. - 1365-3083 .- 0300-9475. ; 44:5, s. 430-436
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, the authors report the use of liquid-liquid partition chromatography (LLPC) in an aqueous polyethylene glycol (PEG)/dextran two-phase system to compare the surface properties (partition properties) of human antibodies and fragments thereof. The surface properties of all the monoclonal antibodies of different classes and subclasses investigated were within the same broad range as that observed for the polyclonal antibodies and no relationship was found between the exposed surfaces of the immunoglobulins (Ig) and their heavy chain isotype. Moreover, Fc fragments from various IgG1, 2 and 4 myeloma proteins were found to exhibit similar surface properties. Employing chimeric antibodies with identical variable regions the authors found that intact IgG1, 2 and 4 displayed identical surface properties, while the corresponding IgA1, IgA2, IgG3, IgE and IgM antibodies differed both from each other and from the IgGs. The surface properties of chimeric IgG3 could be made similar to those of the IgG1, 2 and 4 chimers by partially reducing the length of the hinge section, but new differences in surface properties appeared when their hinges were of similar length. Thus, LLPC can be used to detect differences or similarities in the surface properties of the antigen-binding regions as well as the Fc part in the various isotypes. This can shed light on biological activities such as antigen binding and effector function.
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