Theorie der Orientierung starrer Teilchen mit Wechselwirkung in einer Strömung

Joly, M.

doi:10.1007/bf01526502

Cited by 15 publications

(2 citation statements)

References 17 publications

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“…The polymers and aggregates thereof, randomly oriented at first, would here be exposed to a velocity gradient tending to orient them parallel to the direction of streaming. The orientation would be stabilized by extensive aggregation through lateral intermolecular bonds (9, 28,36,39,52,56), and the mucilage would thus acquire a helical structure (in the case of species exhibiting screw-like motion) evidenced by twisting (42) and by the presence of helically wound microfibrils.…”

Section: Discussionmentioning

confidence: 99%

“…Van der Waals interactions and hydrogen bonds might also contribute to the lateral aggregation of shear-oriented polysaccharide molecules at the surface of motile oscillatoriacean trichomes. The principal theoretical and experimental basis for this speculation has been provided by Joly (28,29,30), who assumes that certain highly asymmetric particles are strongly attracted to each other by London-van der Waals interaction or hydrogen bonding whenever they make momentary mutual contact over sufficiently large portions of their surfaces, i.e., whenever translatory and rotary thermal motion bring them close together in parallel orientation. As the orienting effect of shear increases relative to the randomizing effect of rotary diffusion, the average angle between colliding particles decreases and the frequency of effective collisions (collisions favorable for aggregation) increases accordingly.…”

Section: Discussionmentioning

confidence: 99%

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Shear-oriented Microfibrils in the Mucilaginous Investments of Two Motile Oscillatoriacean Blue-Green Algae

Lamont

1969

J Bacteriol

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Trichomes of two oscillatoriacean blue-green algae execute screw-like gliding motion, but the two organisms differ from each other with respect to the screw sense of motion. Electron microscopy of serial longitudinal sections reveals extracellular microfibrils which lie roughly parallel to streamlines at the surface of each organism. The author proposes that the microfibrils are oriented by shear in a zone just external to the outer unit membrane-like component of the cell wall.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Shear-oriented Microfibrils in the Mucilaginous Investments of Two Motile Oscillatoriacean Blue-Green Algae

Lamont

1969

J Bacteriol

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Fortschritte und Probleme der Rheologie

Peter

1963

Angewandte Chemie

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Anilin sowie rnit ound p-Toluidinam besten unter Stickstoffsubstituierte Indole (86), wie gleichzeitig Hirose, Takagi und Uno [77] sowie wir [72] fanden. Dieser Weg scheint in manchen Fallen gunstiger zu sein als die sogenannte Mohlau-Bischlersche Indolsynthese [78], bei der ct-Bromketone rnit aromatischen Aminen reagieren. V. Berichtigungen zur ersten Mitteilung, Angew. Chem. 65,605 (1953). S. 607, linke Spalte, FuBnote 5 zu erglnzen ist: R. S. 608, linke Spalte, FuBnote 26 I. Amer. chern. SOC. 67, 2089 (1945) statt J. Amer. chern. SOC. 62, 2089 (1945). S. 608, rechte Spalte, FuBnote 46 Th. Thonisoti u. Th. Stevens, J. chem. SOC. (London) 1932, 69 statt 1932, 19. S. 622, rechte Spalte, vorletzte Zeile von Kapitel VII es muB heiBen: ,,XIX llBt sich rnit Natriumhydrosulfit. . ." statt ,,XX IaBt sich rnit Natriumhydrosulfit.. .". Weitere Zitate zu den Arbeiten von Ch. Marschalk sind: DRP 290984; FrdLFortschr. Teerfarb. Fabrikat. 12, 505 (1914-1916); Bull. SOC. chim. France 1952, 952, 955. Der Deutschen Forschungsgetneinschafr , dem Fonds der Chemischen Industrie, der Badischen Anilin-und Soda-Fabrik AG., Ludwigshafen, den Farbenfabriken Bayer AG., Leverkusen, sowie der Research Corporation, New York, danke ich verbindlichst fur die im Laufe der Jahre enipfangenen Unterstiitzungen, die unsere Arbeiten sehr gefordert haben. [A 2191 [ I ] NBheres iiber die Definitionen und Begriffe der Rheologie bei

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The orientation and dissociation field effect of DNA in solution

1963

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INTRODUCTIONA high electric field may affect the electrolyte conductivity of a polyelectrolyte solution with very long stretched polyions in two different ways. An increase of the conductivity because of increased dissociation is generally observed at high field strengths (dissociation field effe~t).l-~ On the other hand, there is an effect of the field on the mean mobility of the charge carriers which may be noticeable even a t moderate field strengths. Due to polarization of the inner ionic atmosphere of the polyions, electric dipoles are induced on these particles, causing an orientation of their long axes in direction of the field. As a consequence of anisotropy of the nonspherical particles, anisotropy of the conductivity is produced in the solution (orientation field effect) .6 This effect has been established experimentally with dilute solutions of highly polymerized polyph~sphates.~*~J In this case, particularly large electric dipole moments are created on the long stretched polyions. The experimental results are in good agreement with theoretical conclusions.6JThe magnitude of the orientation field effect decreases rapidly with decreasing length of the polyions. For this reason all attempts so far to measure the effect for other polyelectrolytes with smaller polyions had failed because of experimental difficulties. By means of a somewhat improved experimental set-up it has been possible now to detect the effect in the case of certain samples of desoxyribonucleic acid (DNA). This substance is of particular interest, since its polyions in the helical form8 are supposed to be fairly rigid, having only a slight flexibility,9J0 in contrast to the polyphosphate ions which are more or less coiled, depending on concentration. This different structure should result in a different concentration dependence of the orientation field effect of polyphosphate and DNA. Thus the measurements with DXA provide an important test of previous discussions on the nature of the orientation field effect. Measurements of the dissociation field effect of DNA have also been performed and discussed.

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Theorie der Orientierung starrer Teilchen mit Wechselwirkung in einer Strömung

Cited by 15 publications

References 17 publications

Shear-oriented Microfibrils in the Mucilaginous Investments of Two Motile Oscillatoriacean Blue-Green Algae

Shear-oriented Microfibrils in the Mucilaginous Investments of Two Motile Oscillatoriacean Blue-Green Algae

Fortschritte und Probleme der Rheologie

The orientation and dissociation field effect of DNA in solution

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