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- Matsuoka, Atsuko, et al.
(författare)
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Correlation of sister chromatid exchange formation through homologous recombination with ribonucleotide reductase inhibition.
- 2004
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Ingår i: Mutat Res. - 0027-5107. ; 547:1-2, s. 101-7
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- We conducted the recombination and sister chromatid exchange (SCE) assays with five chemicals (hydroxyurea (HU), resveratrol, 4-hydroxy-trans-stilbene, 3-hydroxy-trans-stilbene, and mitomycin C) in Chinese hamster cell line SPD8/V79 to confirm directly that SCE is a result of homologous recombination (HR). SPD8 has a partial duplication in exon 7 of the endogenous hprt gene and can revert to wild type by homologous recombination. All chemicals were positive in both assays except for 3-hydroxy-trans-stilbene, which was negative in both. HU, resveratrol, and 4-hydroxy-trans-stilbene were scavengers of the tyrosyl free radical of the R2 subunit of mammalian ribonucleotide reductase. Tyrosyl free radical scavengers disturb normal DNA replication, causing replication fork arrest. Mitomycin C is a DNA cross-linking agent that also causes replication fork arrest. The present study suggests that replication fork arrest, which is similar to the early phases of HR, leads to a high frequency of recombination, resulting in SCEs. The findings show that SCE may be mediated by HR.
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| 3. |
- Sahlin, Fredrik, et al.
(författare)
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2D CFD-analysis of micro-patterned surfaces in hydrodynamic lubrication
- 2004
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Ingår i: Proceedings of the ASME/STLE international joint tribology conference 2004. - New York. ; , s. 1637-1645, s. 1637-1645
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Konferensbidrag (refereegranskat)abstract
- Results of a numerical study of the influence of micro-patterned surfaces in hydrodynamic lubrication of two parallel walls are reported. Two types of parameterized grooves with the same order of depth as the film thickness are used on one stationary wall. The other wall is smooth and is sliding with a specified tangential velocity. Isothermal incompressible two dimensional full film fluid flow mechanics is solved using a Computational Fluid Dynamics method. It is shown that, by introducing a micro-pattern on one of two parallel walls, a net pressure rise in the fluid domain is achieved. This produces a load carrying capacity on the walls which is mainly contributed by fluid inertia. The load carrying capacity increases with Reynolds number. The load carrying capacity is reported to increase with groove width and depth. However, at a certain depth a vortex appears in the groove and near this value the maximum load carrying capacity is achieved. It is shown that the friction force decreases with deeper and wider grooves. Among all geometries studied, optimum geometry shapes in terms of hydrodynamic performance are reported.
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