| 1. |
- Kowalski, Marek, et al.
(författare)
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Physics results from the AMANDA neutrino detector
- 2001
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Ingår i: Proceedings of Science. - 1824-8039. ; HEP2001
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Tidskriftsartikel (refereegranskat)abstract
- In the winter season of 2000, the AMANDA (Antarctic Muon And NeutrinoDetector Array) detector was completed to its nal state. We report on major physicsresults obtained from the AMANDA-B10 detector, as well as initial results of the fullAMANDA-II detector.
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| 2. |
- Rubel, Marek J., et al.
(författare)
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Beryllium and carbon films in JET following D-T operation
- 2003
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Ingår i: Journal of Nuclear Materials. - 0022-3115 .- 1873-4820. ; 313, s. 321-326
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Tidskriftsartikel (refereegranskat)abstract
- After the D-T operation (DTE-1 campaign) at JET a large number of limiter and divertor tiles were dismounted from the torus for ex situ examination. The relative distributions of deuterium, tritium, beryllium and carbon are presented and discussed. Significant asymmetry observed in the distribution of erosion and deposition zones indicates preferential flow of the deuterium background plasma and impurities towards the inner divertor leg. The comparison of the beryllium content on the limiter tiles from the main chamber and the content of this element on the inner divertor tiles clearly proves the beryllium erosion from the main chamber wall and its transport to the divertor. However, no beryllium is detected in the shadowed regions of the divertor where the formation of thick and fuel-rich carbon films occurs. This is interpreted in terms of different mechanisms governing the erosion and transport of Be and C. The results allow a conclusion that the operation with a full beryllium wall would lead to a significantly decreased fuel inventory due to removal of the carbon source.
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| 3. |
- Coad, J. P., et al.
(författare)
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Erosion/deposition in JET during the period 1999-2001
- 2003
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Ingår i: Journal of Nuclear Materials. - 0022-3115 .- 1873-4820. ; 313, s. 419-423
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Tidskriftsartikel (refereegranskat)abstract
- Coated divertor and wall tiles exposed in JET for the 1999-2001 operations have been used to assess erosion/deposition. Deposited films of up to 90 mum thickness at the inner wall of the divertor tiles are, for the most part, enriched in beryllium and other metals, whilst carbon is probably chemically sputtered from these tiles and transported to shadowed regions of the inner divertor. However, from the composition at the surface of the tiles, it appears that the chemical erosion was 'switched off' by reducing the JET vessel wall temperature for the last part of the operations to 200 degreesC. Thick powdery deposits localised at the ion transport limit at each corner of the divertor may be due to physical sputtering. Erosion of the coatings is seen at the outer divertor wall, and on all the inner wall and outer limiter tiles.
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| 4. |
- Laux, M., et al.
(författare)
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Arcing at B4C-covered limiters exposed to a SOL-plasma
- 2003
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Ingår i: Journal of Nuclear Materials. - 0022-3115 .- 1873-4820. ; 313, s. 62-66
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Tidskriftsartikel (refereegranskat)abstract
- Plasma sprayed B4C-layers considered as wall coatings for the W7X stellarator have been studied during and after exposure to TEXTOR and after arcing experiments in vacuum. Arcing through the B4C layer occurred favoured by high power fluxes and not restricted to less stable phases. But this arcing implies an especially noisy scrape-off layer (SOL). Instead of moving retrograde in the external magnetic field, the arc spot on the B4C-layer sticks to the same location for its whole lifetime. Consequently, the arc erodes the entire B4C layer, finally burning down to the Cu substrate. In the neighbourhood of craters the surface contains Cu originating from those craters. This material, hauled to the surface by the arc, is subject to subsequent erosion, transport, and redeposition by the SOL-plasma. The behaviour of arcs on B4C is Most probably caused by the peculiar temperature dependences of the electrical and heat conductivity of B4C.
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| 5. |
- Los, Marek Jan, et al.
(författare)
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Activation and caspase-mediated inhibition of PARP : A molecular switch between fibroblast necrosis and apoptosis in death receptor signaling
- 2002
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Ingår i: Molecular Biology of the Cell. - : American Society for Cell Biology. - 1059-1524 .- 1939-4586. ; 13:3, s. 978-988
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Tidskriftsartikel (refereegranskat)abstract
- Death ligands not only induce apoptosis but can also trigger necrosis with distinct biochemical and morphological features. We recently showed that in L929 cells CD95 ligation induces apoptosis, whereas TNF elicits necrosis. Treatment with anti-CD95 resulted in typical apoptosis characterized by caspase activation and DNA fragmentation. These events were barely induced by TNF, although TNF triggered cell death to a similar extent as CD95. Surprisingly, whereas the caspase inhibitor zVAD prevented CD95-mediated apoptosis, it potentiated TNF-induced necrosis. Cotreatment with TNF and zVAD was characterized by ATP depletion and accelerated necrosis. To investigate the mechanisms underlying TNF-induced cell death and its potentiation by zVAD, we examined the role of poly(ADP-ribose)polymerase-1 (PARP-1). TNF but not CD95 mediated PARP activation, whereas a PARP inhibitor suppressed TNF-induced necrosis and the sensitizing effect of zVAD. In addition, fibroblasts expressing a noncleavable PARP-I mutant were more sensitive to TNF than wild-tvpe cells. Our results indicate that TNF induces PARP activation leading to ATP depletion and subsequent necrosis. In contrast, in CD95-mediated apoptosis caspases cause PARP-1 cleavage and thereby maintain ATP levels. Because ATP is required for apoptosis, we suggest that PARP-1 cleavage functions as a molecular switch between apoptotic and necrotic modes of death receptor-induced cell death.
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| 6. |
- Los, Marek Jan, et al.
(författare)
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Functional characterization of DNase X, a novel endonuclease expressed in muscle cells
- 2000
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Ingår i: Biochemistry. - : American Chemical Society (ACS). - 0006-2960 .- 1520-4995. ; 39:25, s. 7365-7373
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Tidskriftsartikel (refereegranskat)abstract
- The activation of endonucleases resulting in the degradation of genomic DNA is one of the most characteristic changes in apoptosis. Here, we report the characterization of a novel endonuclease, termed DNase X due to its X-chromosomal localization. The active nuclease is a 35 kDa protein with 39% identity to DNase I. When incubated with isolated nuclei, recombinant DNase X was capable of triggering DNA degradation at internucleosomal sites. Similarly to DNase I, the nuclease activity of DNase X was dependent on Ca2+ and Mg2+ and inhibited by Zn2+ ions or chelators of bivalent cations. Overexpression of DNase X caused internucleosomal DNA degradation and induction of cell death associated with increased caspase activation. Despite the presence of two potential caspase cleavage sites, DNase X was processed neither in vitro nor in vivo by different caspases. Interestingly, after initiation of apoptosis DNase X was translocated from the cytoplasm to the nuclear compartment and aggregated as a detergent-insoluble complex. Abundant expression of DNase X mRNA was detected in heart and skeletal muscle cells, suggesting that DNase X may be involved in apoptotic or other biological events in muscle tissues.
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| 7. |
- Necas, M., et al.
(författare)
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New mixed-donor unsymmetrical P-N-P ligands and their palladium(II) complexes
- 2001
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1369-9261 .- 1144-0546. ; 25:10, s. 1256-1263
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Tidskriftsartikel (refereegranskat)abstract
- Unsymmetrical bidentate ligands R2P(E)-N(H)-P(E')R'(2) [R, R' = Ph, OPh, Pr-i; E, E' = O, S, Se] have been synthesised using the condensation reaction of an amino compound, R2P(E)NH2 [R = PhO, Ph; E = O, S, Se], with a phosphorus electrophile, R'P-2(E')CI [R' = Pr-i, Ph, OPh; E' = O, S, Se]. Deprotonated ligands (with (KOBu)-Bu-t) can be treated with Pd(OAC)(2) to give [Ph2P(S)-N-P(OXOPh)(2)](2)Pd, [(Pr2P)-Pr-i(S)-N-P(O)(OPh)(2)](2)Pd and [Ph2P(S)-N-P(S)(OPh)(2)](2)Pd, which show either four-membered or six-membered chelate rings. The new compounds were studied spectroscopically (NMR, IR and Raman) and by X-ray crystallography.
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| 8. |
- Rubel, Marek J., et al.
(författare)
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Fuel accumulation in co-deposited layers on plasma facing components
- 2001
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Ingår i: Journal of Nuclear Materials. - 0022-3115 .- 1873-4820. ; 290, s. 473-477
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Tidskriftsartikel (refereegranskat)abstract
- The work is focused on the determination of the distribution and the total content of deuterium in co-deposits formed in the TEXTOR tokamak on a toroidal belt limiter which is the machine's major plasma facing component (PFC). Limiter tiles in use for 14 100 s of plasma operation were dismounted for examination with surface analysis and microscopy methods. Mapping of the deuterium distribution by means of nuclear reaction analysis (NRA) revealed the presence of deposition zones covering about 35% of the tiles'surface area. Besides C and D, other constituents of the layers were boron, silicon and inconel components. The co-deposit, with a stratified structure and a thickness of up to 50 mum, could be detached from the tiles. Deuterium depth profiling on both sides of the detached flakes and in the underlying graphite substrate enabled the D content in the deposition zones to be estimated at a level of 3.5 x 10(19) cm(-2). Adding the fuel content found in the erosion zone (3-7 x 10(17) cm(-2)) and on the back side of the tile (0.9-1.8 x 10(17) cm(-2)), the total amount of D atoms trapped in all the limiter tiles was assessed to be about 2 x 10(23) atoms. D content in the co-deposits accounted for approximately 10 at.% (C-D/C-C similar to 0.1) which was considered to be low in comparison to much greater values observed in other devices. The results of the ion beam analyses (IBA) agree well with the determination by thermal desorption spectrometry (TDS).
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| 9. |
- Rubel, Marek J., et al.
(författare)
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Ion beam analysis methods in the studies of plasma facing materials in controlled fusion devices
- 2003
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Ingår i: Vacuum. - 0042-207X .- 1879-2715. ; 70:03-feb, s. 423-428
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Tidskriftsartikel (refereegranskat)abstract
- Application of ion beam analysis techniques in the studies of material transport and fuel inventory in the controlled fusion devices is exemplified. Enhanced proton scattering on the carbon isotopes C-12(p,p)C-12, C-13(p,p)C-13 and secondary ion mass spectrometry allowed for determination of carbon erosion and re-deposition on the wall components following the experiments with a tracer ((CH4)-C-13) injection into the plasma edge at the TEXTOR tokamak. For the assessment of the deuterium fuel accumulation in the plasma facing components depth profiling by means of nuclear reaction analysis, He-3(d,p)He-4, was performed. Advantages and limitations of those nuclear methods in solving experimental problems are addressed.
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| 10. |
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