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(110) Production(s) de LORMAN V.
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Screwlike Order, Macroscopic Chirality, and Elastic Distortions in High-density DNA Mesophases 
Auteur(s): Manna Federico, Lorman V., Podgornik R., Zeks B.
(Article) Publié:
Physical Review E: Statistical, Nonlinear, And Soft Matter Physics, vol. 75 p.030901(R) (2007)
Ref HAL: hal-00338927_v1
PMID 17500660
DOI: 10.1103/PhysRevE.75.030901
WoS: 000245324300006
Exporter : BibTex | endNote
17 Citations
Résumé: We investigate a new screwlike liquid-crystalline ordering in solutions of helical biopolymers and its influence on the state of individual molecules. In the resulting mesophase translational and rotational motions of molecules are coupled in screw fluctuations. We show that in contrast to the case of conventional chiral liquid crystals the elastic distortion does not twist the screw order but leads to overwinding of individual helical molecules. This explains the peculiarities of high-density DNA mesophases.
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Pressing over Tubulin
Auteur(s): Monnier S., Estephan E., Parmeggiani A., Marchal S., Lange R., Bec N., Lorman V., Larroque C.
(Article) Publié:
European Biophysics Journal, vol. 36 p.S123 (2007)
Texte intégral en Openaccess : 
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Pressing over Tubulin
Auteur(s): Monnier S., Estephan E., Parmeggiani A., Marchal S., Lange R., Bec N., Lorman V., Larroque C.
Conference: 6th European Biophysics Congress (London, GB, 2007-07-14)
Actes de conférence: Proceedings of the 6th EBSA European Biophysics Congress, vol. p.p. 279 (2007)
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Polarity, Chirality and Helicity in Condensed Phases of Biomolecules and Bioassemblies
Auteur(s): Lorman V.
Conference: 11th European Meeting on Ferooelectricity (Bled, SI, 2007-09-03)
Actes de conférence: Proceedings of the 11th EMF, vol. p.- (2007)
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Discontinuous change in smectic layer thickness in ferrielectric liquid crystals
Auteur(s): Panov V.P., Vij J.K., Panarin Yu.P., Blanc C., Lorman V., Goodby J.W.
(Article) Publié:
Physical Review E: Statistical, Nonlinear, And Soft Matter Physics, vol. 75 p.042701 (2007)
Texte intégral en Openaccess : 
Ref HAL: hal-00378244_v1
PMID 17500942
DOI: 10.1103/PhysRevE.75.042701
WoS: 000246073900100
Exporter : BibTex | endNote
19 Citations
Résumé: The temperature dependence of the thickness of thick free-standing films is studied using a high-resolution film thickness measurement technique. A small discontinuity in the temperature dependence of the smectic layer thickness at every phase transition between ferro-, ferri-, and antiferroelectric phases is observed. We show that the major contribution to it arises from a change in the smectic tilt angle.
Commentaires: 4 pp.
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Polarity and Chirality in NCP Mesophases and Chromatin Fibers
Auteur(s): Manna Federico, Lorman V. , Podgornik R., Zeks B.
(Article) Publié:
Molecular Crystals And Liquid Crystals, vol. 478 p.83-97 (2007)
Ref HAL: hal-00378228_v1
DOI: 10.1080/15421400701686918
WoS: 000252090900008
Exporter : BibTex | endNote
1 Citation
Résumé: We propose a unified mechanism of phase transitions in the high density solutions of Nucleosomal Core Particles. We demonstrate its relation with the high shape and charge anisotropy of the NCP due to the DNA wrapping around the histone protein core. Hexagonal-to-lamellar transition in the solution of NCP columnar aggregates is shown to be driven by the condensation of the periodic antiparallel polar vector field. The transition results in the polar dyadic axes correlations. Fine structure of the NCP organization is also explained, namely the correlated tilting of NCP with respect to the column axis.
Commentaires: The 21st International Liquid Crystal Conference (July 2 -7, 2006), Keystone, Colorado (USA)
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Chiral Free-standing Film Micromotor
Auteur(s): Blanc C., Lorman V., Goc F., Nobili M.
Conference: The 21st International Liquid Crystal Conference (Keystone, US, 2006-07-02)
Ref HAL: hal-00326961_v1
Exporter : BibTex | endNote
Résumé: Symmetry arguments show that a flow of matter through a chiral medium can induce a collective molecular rotation. We report the study of such a linear coupling between a gas flow and molecular motion in thick free standing films of SmC* liquid crystal. This effect could be used to develop liquid crystalline micromotors potentially useful for microfluidics and micromechanics. Typical evolving target patterns have been recently observed by Tabe et al. [1] in a Langmuir monolayer of chiral liquid crystal molecules deposited on glycerol. We designed a more robust system composed of a free standing film of chiral molecules, without any liquid substrate. The flow of gas through the film is tuned by controlling the gas chemical potential. Direct pattern observation needs no Brewster angle microscope and is done under optical polarizing microscope. The whole set-up allows a quantitative study of the flow/rotation coupling phenomenon. The system shows a very rich spatio-temporal behavior. Here we focus on patterns obtained in a film suspended on a circular frame. In this geometry, a steady-state is attained where a spiral pattern is formed (see fig.1). We obtain the set of equations which govern the dynamics of the film under the gas flow. In a particular case, the equations involve only the c-director dynamics [2]. In the steady-state regime, they reduce to the competition of the elastic torque and an external torque induced by the flow. The observed static spiral patterns confirm the existence of such an external torque.
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