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| 2. |
- Butorin, S. M., et al.
(författare)
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Resonant inelastic soft X-ray scattering at the 4d edge of Ce-based heavy fermion materials
- 1999
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Ingår i: Journal of Electron Spectroscopy and Related Phenomena. - 0368-2048 .- 1873-2526. ; 101-103, s. 783-786
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Tidskriftsartikel (refereegranskat)abstract
- Resonant X-ray scattering measurements were performed on CeB6, CeAl, γ-Ce, and α-Ce at various incident-photon energies near the Ce 4d threshold. A pronounced inelastic scattering structure which has 4f character is observed at about 4 eV below the elastic peak. The structure shows a distinct resonant behavior as well as a dependence on the degree of 4f hybridization and can therefore be attributed to charge-transfer excitations to the 4f0 state. The intensity of the elastic peak increases when going from the systems with low Kondo temperature TK to those with high TK which is consistent with a Kondo scale behavior. By analyzing the scattering data, a controversial issue on the validity of a single-impurity Anderson model in heavy-fermion materials is addressed.
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| 3. |
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| 4. |
- Butorin, SM, et al.
(författare)
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Resonant inelastic soft-X-ray scattering at the 4d edge of Ce-based heavy-fermion materials
- 1999
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Ingår i: JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA. - 0368-2048. ; 103, s. 783-786
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Resonant X-ray scattering measurements were performed on CeB6, CeAl, gamma-Ce, and alpha-Ce at various incident-photon energies near the Ce 4d threshold. A pronounced inelastic scattering structure which has 4f character is observed at about 4 eV below th
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| 7. |
- Kim, S. K., et al.
(författare)
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Binding of RecA to anti-parallel poly(dA) · 2poly(dT) triple helix DNA
- 1995
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Ingår i: Biochimica et Biophysica Acta - Gene Structure and Expression. - : Elsevier BV. - 0167-4781. ; 1264:1, s. 129-133
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Tidskriftsartikel (refereegranskat)abstract
- Binding of RecA protein to conventional anti-parallel poly(dA). 2poly(dT) tripler DNA has been studied using flow linear dichroism spectroscopy. The association requires the presence of cofactor analog adenosine 5'-O-3-thiotriphosphate (ATP gamma S) and occurs with a rate similar to that for the association of RecA to double-stranded poly(dA) poly(dT) DNA. The binding of RecA to DNA stiffens the nucleotide chain, as evidenced from high orientation already at low shear rates, and the complex with tripler DNA appears to be at least as stiff as that with the duplex DNA. Therefore, the observation of a lower magnitude of the LD spectrum at 260 nm, in the triplex-RecA compared to the duplex-RecA complex, but retained magnitude of protein LD at 280 nm, indicates a markedly impaired orientation of nucleo-bases, possibly reflecting a perturbation by RecA on the third strand making its bases deviate strongly from perpendicularity. The circular dichroism spectrum: appearing immediately after dissociation of RecA by SDS, suggests an intact tripler structure, meaning that complexation with RecA has not dissociated the third strand. In conclusion, binding of RecA to tripler DNA does not modify the main organisation of the strands, but could affect the base-base interactions between them. Tilted bases could reflect a conformational change that RecA imposes also on the biological intermediate tripler structure to relax the base-base hydrogen bonding between the DNA strands.
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| 8. |
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| 9. |
- Morse, S, et al.
(författare)
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Dissociative photoionisation of OCS from threshold to 40.8 eV
- 1999
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Ingår i: INTERNATIONAL JOURNAL OF MASS SPECTROMETRY. - : ELSEVIER SCIENCE BV. - 1387-3806. ; 184:1, s. 67-74
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Energy-analysed photoelectrons have been measured in coincidence with product ions from photoionisation of carbonyl sulphide at 21.21 and 40.8 eV photon energy. Yields of the different products and kinetic energy release distributions in fragment ion form
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| 10. |
- Tuite, Eimer, 1966, et al.
(författare)
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Effects of intercalators on complexation of RecA with duplex DNA
- 1995
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Ingår i: Biochemistry. - : American Chemical Society (ACS). - 1520-4995 .- 0006-2960. ; 34:50, s. 16365-16374
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Tidskriftsartikel (refereegranskat)abstract
- To elucidate the binding mode of recombination protein A (RecA) to double-stranded (ds) DNA, the effects on the RecA-DNA interaction of several mono- and bisintercalators of the acridine, phenanthridine, and cyanine classes have been investigated by linear dichroism spectroscopy. Simple monointercalators lacking side chains efficiently promoted the binding of RecA to dsDNA in the absence of nucleotide cofactor, which is otherwise required. Bisintercalators varied in their ability to induce RecA binding, while monointercalators with aminoalkyl side chains proved inefficient. Modification of DNA structure by the intercalator appears to be necessary for induction of RecA binding, but if the intercalator has a bulky minor-groove-binding side chain, it does not induce RecA binding. In detailed studies with acridines, neither the binding geometry of intercalators nor the structure of DNA was significantly modified upon binding of RecA without cofactor. Judged by circular dichroism, similar ReA conformational changes accompanied bis-9-aminoacridine- and ATPyS-induced RecA association with DNA. In the presence of ATPyS, the intercalators inhibited the rate of RecA binding to dsDNA and were extruded from DNA upon binding of RecA. This competitive aspect may suggest that intercalation of some amino acid residue(s) plays a role in nucleotide-induced RecA binding. The stoichiometry of the RecA-DNA-intercalator filament was determined; in the fully formed filament the base pair:intercalator ratio is 2, and the base pair:RecA ratio also 2. This contrasts with a base pair:RecA ratio of 3 in the ATPyS-induced filament, although in both cases the DNA experiences 50% extension.
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