| 1. |
- Sjöberg, Maria, et al.
(författare)
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Egendom, kön och förändring
- 2003
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Ingår i: Hans och Hennes. - Uppsala : Historiska institutionen, Uppsala universitet. ; , s. 5-36
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 2. |
- Björklund, Patrik, et al.
(författare)
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Västerås slott : Slott och borgar
- 2000
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Rapport (populärvet., debatt m.m.)abstract
- En majoritet av dagens byggnadsuppgifter gäller att hantera det redan byggda. När vi står inför situationen att restaurera en befintlig byggnad är det viktigt att förstå olika tidsperioders stilideal liksom byggnadsteknik och material. Först då kan vi göra en väl avvägd analys, som tar tillvara och utvecklar de kvaliteter som byggnaderna själva besitter. Därför är utbildningen upplagd som ett växelspel mellan föreläsningar, seminarier, exkursioner och en för året vald studieuppgift.Slott och borgar har varit läsårets tema. Vi har valt att arbeta med Västerås och Örebro slott - två ganska bortglömda Vasaslott som är väl värda att lyfta fram. Särskilt har vi studerat de senaste 300 årens förändringar, som inte tidigare ägnats lika stora forskarmöda som medelitden och Vasatiden. I dessa två exempel finns en provkarta på estetiska, praktiska och tekniska ingrepp från Carl Hårlemans tid och fram till idag.Studierna har således omfattat både gestaltning, funktion och byggnadsteknik. Avsikten är att visa på kvaliteter i de omvandlingar och restaureringar som skett, men också att peka på problem och analysera olika möjligheter inför framtiden. Arbetet har skett i samarbete med Statens fastighetsverk och är tänkt att utgöra ett underlag till vårdprogram och framtida restaureringsinsatser.
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| 3. |
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| 4. |
- Engstrom, Maria, et al.
(författare)
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Ab initio g-tensor calculations of the thioether substituted tyrosyl radical in galactose oxidase
- 2000
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Ingår i: Chemical Physics Letters. - 0009-2614 .- 1873-4448. ; 319:04-mar, s. 191-196
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Tidskriftsartikel (refereegranskat)abstract
- The tyrosyl radical in galactose oxidase is covalently cross-linked to a neighboring cysteine residue through a thioether bond. The role of this sulfur cross-link has been discussed ever since the crystal structure of the enzyme was solved. In the present work, the ab initio multiconfigurational linear response method is applied to calculate the g-tensor of unsubstituted and thioether substituted phenoxyl radicals. In contrast to some previous interpretations, but in agreement with recent EPR measurements, we find that the sulfur substitution induces only minor shifts in the g-tensor components. The spin distribution retains the odd-alternant pattern of the unsubstituted radical and only a small amount of spin is localized to the sulfur center.
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| 5. |
- Engstrom, Maria, et al.
(författare)
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Density functional theory calculations of electron paramagnetic resonance parameters of a nitroxide spin label in tissue factor and factor VIIa protein complex
- 2002
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207 .- 1089-5647. ; 106:47, s. 12354-12360
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Tidskriftsartikel (refereegranskat)abstract
- The electron paramagnetic resonance (EPR) g and N-14 hyperfine coupling (A) tensors of a nitroxide spin label are calculated with density-functional theory (DFT). The influence on the spin label from nearby amino acids in the extracellular part of tissue factor (sTF) and activated factor VII (FVIIa) protein complex is investigated. For that purpose, the nitroxide unit and six surrounding amino acids within 5 Angstrom are selected on the basis of a molecular mechanics structure of the protein complex. The effects of the surroundings on the EPR parameters of the spin label can be divided into indirect effects caused by the induced structure changes of the spin label and direct effects. The structural changes are larger in the present case. The experimentally measurable hyperfine tensor component perpendicular to the molecular plane of the spin label, A(zz), as well as the g tensor component along the NO direction, g,,, are significant probes of the intramolecular structure of the spin label. This indicates the possibility of relating EPR properties to the geometric structure of radical sites. The direct environmental effects on the g tensor from the surrounding amino acids mainly affect the second-order spin-orbit/orbital Zeeman cross-term contributions from the spin label itself. The direct effects originating elsewhere in the model are small. Neither the g nor A tensors display additivity of the effects of individual amino acids on the final observable. The results underline the feasibility of DFT calculations of the EPR parameters in large molecular systems, such as spin labels and other radicals in proteins.
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| 6. |
- Engstrom, Maria, et al.
(författare)
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Hydrogen bonding to tyrosyl radical analyzed by ab initio g-tensor calculations
- 2000
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Ingår i: Journal of Physical Chemistry A. - : American Chemical Society (ACS). - 1089-5639 .- 1520-5215. ; 104:21, s. 5149-5153
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Tidskriftsartikel (refereegranskat)abstract
- Hydrogen bonding to the tyrosyl radical in ribonucleotide reductase (RNR) has been simulated by a complex between the phenoxyl radical and a water molecule. Multiconfigurational self-consistent field linear response theory was used to calculate the g-tensor of the isolated phenoxyl radical and of the phenoxyl-water model. The relevance of the model was motivated by the fact that spin density distributions and electron paramagnetic resonance (EPR) spectra of the phenoxyl and tyrosyl radicals are very similar. The calculated g-tensor anisotropy of the phenoxyl radical was comparable with experimental findings for tyrosyl in those RNRs where the H-bond is absent: g(x) = 2.0087(2.0087), g(y) = 2.0050(2.0042), and g(z) = 2.0025(2.0020), where the tyrosyl radical EPR data from Escherichia coli RNR are given in parentheses. The hydrogen bonding models reproduced a shift toward a lower g(x) value that was observed experimentally for mouse and herpes simplex virus RNR where the H-bond was detected by electron-nuclear double resonance after deuterium exchange. This decrease could be traced to lower angular momentum and spin-orbit coupling matrix elements between the ground B-2(1) and the first excited B-2(2) states (oxygen lone-pair n to pi(SOMO) excitation) upon hydrogen bonding in a linear configuration. The g(x) value was further decreased by hydrogen bonding in bent configurations due to a blue shift of this excitation.
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| 7. |
- Engstrom, Maria, et al.
(författare)
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MCSCF and DFT calculations of EPR parameters of sulfur centered radicals
- 2000
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Ingår i: Chemical Physics Letters. - 0009-2614 .- 1873-4448. ; 328:06-apr, s. 483-491
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Tidskriftsartikel (refereegranskat)abstract
- The EPR parameters of sulfur centered radicals are different depending on the radical structure, charge and solvent. That is, the g- and A-tensor components provide significant patterns which may distinguish sulfur radical structures from each other. In the present work, these EPR parameters were calculated for monosulfide radicals (RS'), disulfide radicals (RSS.), radical cations ((RSSR+)-S-.) and anions ((RSSR-)-S-.), with R = CH3, using the MCSCF linear response and DFT/B3LYP methods. Results were in agreement with experimental data for the cases when well-resolved EPR spectra are available. Especially, the assignment of the disulfide anion in ribonucleotide reductase was confirmed. The results indicate that investigations with the present computational methods on refined structures and solvent modeling may provide interpretations of experimental data on unassigned radical species.
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| 8. |
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| 9. |
- Feifel, Raimund, et al.
(författare)
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Interference Quenching of v
- 2002
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Ingår i: Physical Review Letters. ; 89:10, s. 103002-1
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Tidskriftsartikel (refereegranskat)
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| 10. |
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