Preliminary experimental tests of local erosion at river piers with a particular shape

Ciaravino, L.; Ciaravino, G.

doi:10.2495/rm090231

Cited by 3 publications

(3 citation statements)

References 5 publications

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“…The in iifro MN assay in V79 cells was conducted essentially as previously described by Ciaravino er (11. (16) in studies examining the clastogenicity of quinolones and related compounds. Briefly, V79 cells were quinolone-treated for up to to 3 h in six well plates after which time the medium was removed and replaced with fresh drug-free medium containing 3 pg/mL cytochalasin B to block cytokinesis.…”

Section: Methodsmentioning

confidence: 99%

Photogenotoxicity of Fluoroquinolones in Chinese Hamster V79 Cells: Dependency on Active Topoisomerase II

Snyder

Cooper

1999

Photochem & Photobiology

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The Chinese hamster V79 lung cell in vitro micronucleus assay was adapted to detect and quantify phototoxicity and photogenotoxicity of fluoroquinolones. Using this assay, the quinolones were ranked in terms of decreasing phototoxicity: clinafloxacin >> lomefloxacin, sparfloxacin >> trovafloxacin, nalidixic acid, ofloxacin, ciprofloxacin > enoxacin, norfloxacin. This rank order agrees well with published studies utilizing various other phototoxicity models and establishes this approach as a fast and sensitive way to characterize the phototoxic potential of quinolones. Nearly complete inhibition of phototoxicity was observed if the cells were pretreated for as little as 1 min with 10-20 mM sodium azide prior to the addition of quinolone. An identical azide effect was seen in unirradiated quinolone-and etoposide-treated cells. These findings are consistent with a model in which sodium azide renders DNA topoisomerase I1 catalytically inactive. In this state, topoisomerase I1 cannot initiate DNA strand cleavage and the DNAkopoisomerase complex becomes insensitive to quinolones and other topoisomerase I1 inhibitors. The fact that azide reduces both UV-dependent and UV-independent toxicity and clastogenicity strongly suggests a common mechanism of toxicity dependent on the formation of topoisomerase-induced DNA double-strand breaks. c I Y W Anicrican S <~i c , c ! l t ) t l'h~i[<>hi~il~>g) 003 I -X65S/YY SS ( ) ( I -0 O(I -tAhh,-r~'i~irions: CAT.

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Section: Methodsmentioning

confidence: 99%

Photogenotoxicity of Fluoroquinolones in Chinese Hamster V79 Cells: Dependency on Active Topoisomerase II

Snyder

Cooper

1999

Photochem & Photobiology

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“…In the context of the research programmes mentioned in the Introduction [23,24], scour tests were carried out around bottom sills and river piles.…”

Section: Preliminary Experimental Testsmentioning

confidence: 99%

Technical Notes and Preliminary Experimental Tests on Scours Downstream of Bottom Sills in Asymmetrical Streams

Ciaravino¹,

Ciaravino²

2017

Sixth International Conference on Advances in Civil, Structural and Environmental Engineering - ACSEE 2017

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Hydrographic networks are becoming increasingly subject to unsteady flow regimes. These may be the result of a torrential habitat or because the flow is regulated by detention structures and can result in morphological instability. In such cases, the flow (which often divides into more than one branch) may meander along the river bed close to the bank, causing local scours to the bank and to any structures built along the river. A common technical practice is to employ bottom sills in order to stabilise mobile river beds and protect them from scour. This paper analyses some experimental tests conducted on bottom sills and points out that when the stream meanders unpredictably in the river bed or when the sill is at an angle to the stream, even though this flows in a single direction, the scour phenomenon is accentuated. As a result, assessments of scour in the proximity of river management works, carried out using the empirical formulas normally adopted in technical practice, may turn out to be totally insufficient.

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“…The problem of scour around isolated structures in stream flow, such as bridge piers sunk into the river bed, has been widely studied as testified by the international scientific literature concerning this topic. Early studies aimed to determine the field of motion and the mechanical schema of the erosive phenomenon [1][2][3], others assessed methodologies and relations for estimating scour entity [4][5][6][7][8][9][10][11][12][13][14][15], while later researches studied the evolution of the erosive phenomenon over time [16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Experimental Tests of Local Scour at Circular River Piers with Truncated Cone Foundation

Ciaravino¹,

Ciaravino²

2016

Fouth International Conference on Advances in Civil, Structural and Construction Engineering - CSCE 2016

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Stream flow in mobile river beds gives rise to scour phenomena around river piers that may jeopardize the stability of the bridge. As scour is dependent on pier shape (among other factors), estimating equations generally introduce shape coefficients. In the present study experimental tests concerning scour phenomena have been carried out on a particular shape of the already effective circular piers in order to determine if any improvement is verified in their shape coefficient (with a corresponding decrease in scour). In particular, the circular pier foundation has been shaped as a truncated cone, partially or totally sunk into the mobile bed. In the experimental tests a preliminary comparison has been effected between scour at uniform circular pier and non uniform piers with two different values of bevel angle for the truncated cone foundation. Experimental results have showed that, for both values, the scour depth has been lower than that identified in experimental tests conducted on circular piers of the same diameter but without the truncated cone foundation.

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Preliminary experimental tests of local erosion at river piers with a particular shape

Cited by 3 publications

References 5 publications

Photogenotoxicity of Fluoroquinolones in Chinese Hamster V79 Cells: Dependency on Active Topoisomerase II

Photogenotoxicity of Fluoroquinolones in Chinese Hamster V79 Cells: Dependency on Active Topoisomerase II

Technical Notes and Preliminary Experimental Tests on Scours Downstream of Bottom Sills in Asymmetrical Streams

Experimental Tests of Local Scour at Circular River Piers with Truncated Cone Foundation

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