| 1. |
- Kolczewski, C., et al.
(författare)
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Detailed study of pyridine at the C1s and N1s ionization thresholds : The influence of the vibrational fine structure
- 2001
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 115:14, s. 6426-6437
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Tidskriftsartikel (refereegranskat)abstract
- High resolution, vibrationally resolved, near-edge x-ray absorption fine structure (NEXAFS) spectra at the C 1s and N 1s ionization thresholds of pyridine and deuterated d(5)-pyridine in the gas phase have been recorded. The high resolution of 65 meV (150 meV) at the C s (N 1s) ionization thresholds reveals vibrational structures in the spectra. Detailed ab initio and density functional theory (DFT) calculations were performed to interpret the experimental spectra and to assign the observed peaks. In particular we focused on the previously unexplained intensity ratio for the two components of the C1s -->1 pi* transition. For this transition the vibrational structure is included through a linear coupling model in the DFT calculations and leads to the experimentally observed similar to2:3 intensity ratio between the two pi* components in the C1s spectrum rather than the similar to3:2 ratio obtained without vibrational effects. After inclusion of relaxation effects in the excited states, in addition to the vibrational effects, both theoretical methods yield almost perfect agreement with experiment.
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| 2. |
- Amnell, T, et al.
(författare)
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Now, Next, and Future
- 2001
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Ingår i: Modelling and Verification of Parallel Processes (MOVEP'2k), Nantes, France June 19 to 23, 2000. LNCS Tutorial 2067.. ; , s. 100-125
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Konferensbidrag (refereegranskat)
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| 3. |
- Behrmann, G, et al.
(författare)
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Efficient Guiding Towards Cost-Optimality in UPPAAL
- 2001
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Ingår i: 7th International Conference on Tools and Algorithms for the Construction and Analysis of Systems (TACAS'01). Genova, Italy, April 2 to 6, 2001. LNCS 2031. ; , s. 174-188
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Konferensbidrag (refereegranskat)
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| 4. |
- Behrmann, G, et al.
(författare)
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Minimum-Cost Reachability for Priced Timed Automata
- 2001
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Ingår i: 4th International Workwhop on Hybrid Systems: Computation and Control (HSCC'01). Rome, Italy, March 28 to 30, 2001. LNCS 2034. ; , s. 147-161
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Konferensbidrag (refereegranskat)
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| 5. |
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| 6. |
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| 7. |
- Henriksson, Gunnar, et al.
(författare)
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Is cellobiose dehydrogenase from Phanerochaete chrysosporium a lignin degrading enzyme?
- 2000
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Ingår i: Biochimica et Biophysica Acta - Protein Structure and Molecular Enzymology. - 0167-4838 .- 1879-2588. ; 1480:02-jan, s. 83-91
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Tidskriftsartikel (refereegranskat)abstract
- Cellobiose dehydrogenase (CDH) is an extracellular redox enzyme of ping-pong type, i.e. it has separate oxidative and reductive half reactions. Several wood degrading fungi produce CDH, but the biological function of the enzyme is not known with certainty. It can, however, indirectly generate hydroxyl radicals by reducing Fe3+ to Fe2+ and O-2 to H2O2. Hydroxyl radicals are then generated by a Fenton type reaction and they can react with various wood compounds, including lignin. In this work we study the effect of CDH on a non-phenolic lignin model compound (3,4-dimethoxyphenyl glycol). The results indicate that CDH can affect lignins in three important ways. (1) It breaks beta-ethers; (2) it demethoxylates aromatic structures in lignins; (3) it introduces hydroxyl groups in non-phenolic lignins. The gamma-irradiated model compound gave a similar pattern of products as the CDH treated model compound? when the samples were analyzed by HPLC, suggesting that hydroxyl radicals are the active component of the CDH system.
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| 8. |
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| 9. |
- Hilden, L., et al.
(författare)
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Do the extracellular enzymes cellobiose dehydrogenase and manganese peroxidase form a pathway in lignin biodegradation?
- 2000
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Ingår i: FEBS Letters. - 0014-5793 .- 1873-3468. ; 477:02-jan, s. 79-83
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Tidskriftsartikel (refereegranskat)abstract
- The extracellular enzyme manganese peroxidase is believed to degrade lignin by a hydrogen peroxide-dependent oxidation of Mn(II) to the reactive species Mn(III) that attacks the lignin, However, Mn(III) is not able to directly oxidise the non-phenolic lignin structures that predominate in native lignin, We show here that pretreatment of a non-phenolic lignin model compound with another extracellular fungal enzyme, cellobiose dehydrogenase, allows the manganese peroxidase system to oxidise this molecule. The mechanism behind this effect is demethoxylation and/or hydroxylation, i.e. conversion of a nonphenolic structure to a phenolic one, mediated by hydroxyl radicals generated by cellobiose dehydrogenase, This suggests that cellobiose dehydrogenase and manganese peroxidase may act in an extracellular pathway in fungal lignin biodegradation, Analytical techniques used in this paper are reverse-phase high-pressure liquid chromatography, gas chromatography connected to mass spectroscopy and UV-visible spectroscopy.
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| 10. |
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