24 research outputs found
Universal soft matter template for photonic applications
No full textA new class of high efficiency photonic devices can be realized by combining the optical properties of anisotropic, soft, composite materials with re-configurability, owing to a specific confining geometry and to high response properties. A light sculptured polymeric template is used to micro/nanoconfine a wide selection of organic elements, stabilized through self-organization processes at the nanoscale. We exploit a general purpose method, used to align several kinds of liquid crystalline materials: an excursus of well known optical, electro-optical and all-optical effects is reported, which confirms the capability of our polymeric template to induce self-organization, without the need of any kind of surface chemistry. © The Royal Society of Chemistry 2011
General purpose soft template for photonic applications. From all-optical to electrical reconfigurability
No full textIn this paper we report on the realization and characterization of a polymer template sculptured in photosensitive material on a chemical inert surface, devoted to micro/nano-confinement of a wide range of organic components, with self-arrangement properties at the nanoscale. The high quality morphology of the polymeric micropattern arrays is obtained by combining a nano-precision level optical holographic setup and a multi-step chemico-physical process. The general purpose template represents the basic platform to be filled with different soft composite materials: Due to their self organization capabilities, light responsive Liquid Crystals (LC) and short pitch Cholesteric LC have been investigated. © 2012 Taylor and Francis Group, LLC
Soft periodic microstructures containing liquid crystals
No full textAn empty polymeric structure has been realized by combining a high precision level optical holographic setup and a selective microfluidic etching process. The distinctive features of the realized periodic microstructure enabled aligning several kinds of liquid crystal (LC) compounds, without the need of any kind of surface chemistry or functionalization. In particular, it has been possible to exploit light sensitive LCs for the fabrication of all-optical devices, cholesteric and ferroelectric LCs for ultrafast electro-optical switches, and a common LC for a two-dimensional periodic structure with high anisotropy. All-optical and electro-optical experiments, performed for investigating the samples in terms of switching voltages and response times, confirm good performances of the realized devices. © 2013 American Chemical Society
Composite holographic gratings containing light-responsive liquid crystals for visible bichromatic switching
No full text(Figure Presented) Polymeric microstructures, produced in a multi-step chemico-physical process, confine and stabilize a well-aligned nematic liquid crystal (NLC) film, which is doped with a high-performance mesogenic azobenzene dye, sensitive in the visible range. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Short pitch cholesteric electro-optical device based on periodic polymer structures
No full textThe helical flexoelectro-optic effect produces a submillisecond, temperature-independent in-plane rotation of the optical axis and is potentially interesting for the display industry. The main drawback is that it relies on a texture, the uniform lying helix (ULH), which is intrinsically unstable. We present a method based on the use of periodic polymeric microchannels to create highly ordered and stable ULH structures. Electro-optic measurements performed on a test device show a large contrast ratio between bright and dark states (better then 100:1), fast switching (200 μs), and large optical rotation (>30°). © 2009 American Institute of Physics
Exposure of Vicia faba to sulcotrione pesticide induced genotoxicity
No full textISI Document Delivery No.: 949IKTimes Cited: 0Cited Reference Count: 45Cited References: ARNON DI, 1949, PLANT PHYSIOL, V24, P1, DOI 10.1104/pp.24.1.1 Bombail V, 2001, CHEMOSPHERE, V44, P383, DOI 10.1016/S0045-6535(00)00300-3 Bonnet JL, 2008, ARCH ENVIRON CON TOX, V55, P576, DOI 10.1007/s00244-008-9145-2 Cavas T, 2003, MUTAT RES-GEN TOX EN, V538, P81, DOI 10.1016/S1383-5718(03)00091-3 Cavas T, 2005, ENVIRON TOXICOL PHAR, V19, P107, DOI 10.1016/j.etap.2004.05.007 Chaabane H, 2005, J AGR FOOD CHEM, V53, P4091, DOI 10.1021/jf040443c Chaabane H, 2007, WATER RES, V41, P1781, DOI 10.1016/j.watres.2007.01.009 Chabaane H., 2008, PEST MANAG SCI, V64, P86 Cherrier R, 2004, AGRONOMIE, V24, P29, DOI 10.1051/agro:2003057 Cherrier R, 2005, PEST MANAG SCI, V61, P899, DOI 10.1002/ps.1105 de Lima Patricia Danielle Lima, 2005, Genet Mol Res, V4, P822 DEKERGOMMEAUX DJ, 1983, MUTAT RES, V124, P69, DOI 10.1016/0165-1218(83)90186-6 Dyson JS, 2002, J ENVIRON QUAL, V31, P613 Eyheraguibel B, 2011, J AGR FOOD CHEM, V59, P4868, DOI 10.1021/jf1047282 Eyheraguibel B, 2010, J AGR FOOD CHEM, V58, P9692, DOI 10.1021/jf101792h Foltete AS, 2011, CHEMOSPHERE, V85, P1624, DOI 10.1016/j.chemosphere.2011.08.026 Gadeva P, 2008, MUTAT RES-GEN TOX EN, V652, P191, DOI 10.1016/j.mrgentox.2008.02.007 Goupil P., 2011, ECOTOXICOLOGY, V20, P329 Grant WF, 1998, MUTAT RES-REV MUTAT, V410, P291, DOI 10.1016/S1383-5742(98)00004-0 Hartmann A, 2001, FOOD CHEM TOXICOL, V39, P843, DOI 10.1016/S0278-6915(01)00031-X Iarmarcovai G, 2006, TOXICOL LETT, V166, P1, DOI 10.1016/j.toxlet.2006.05.015 Kim JS, 2002, PHOTOSYNTHETICA, V40, P541, DOI 10.1023/A:1024395801360 Klobucar GIV, 2003, AQUAT TOXICOL, V64, P15, DOI 10.1016/S0166-445X(03)00009-2 Kontek R, 2007, J APPL GENET, V48, P359, DOI 10.1007/BF03195232 Krishna G, 2000, MUTAT RES-FUND MOL M, V455, P155, DOI 10.1016/S0027-5107(00)00117-2 Llorente MT, 2002, ECOTOXICOLOGY, V11, P27, DOI 10.1023/A:1013741012993 MA TH, 1995, MUTAT RES-ENVIR MUTA, V334, P185, DOI 10.1016/0165-1161(95)90010-1 MacKinney G, 1941, J BIOL CHEM, V140, P315 Marcano L, 2004, ENVIRON RES, V94, P221, DOI 10.1016/S0013-9351(03)00121-X Mattiuzzo M, 2006, CARCINOGENESIS, V27, P2511, DOI 10.1093/carcin/bgl102 MAYONADO DJ, 1989, PESTIC BIOCHEM PHYS, V35, P138, DOI 10.1016/0048-3575(89)90111-9 Rouchaux J., 2001, TOXICOL ENVIRON CHEM, V79, P211, DOI DOI 10.1080/02772240109358989 Russo C, 2004, ECOTOX ENVIRON SAFE, V57, P168, DOI 10.1016/S0147-6513(03)00027-7 SCHULZ A, 1993, FEBS LETT, V318, P162, DOI 10.1016/0014-5793(93)80013-K SECOR J, 1994, PLANT PHYSIOL, V106, P1429 Seoane AI, 2001, MUTAT RES-GEN TOX EN, V490, P99, DOI 10.1016/S1383-5718(00)00145-5 Siu WHL, 2004, AQUAT TOXICOL, V66, P381, DOI 10.1016/j.aquatox.2003.10.006 SOEDA T, 1987, PESTIC BIOCHEM PHYS, V29, P35, DOI 10.1016/0048-3575(87)90082-4 Sokal R.R., 1981, BIOL RES Souguir D, 2008, PROTOPLASMA, V233, P203, DOI 10.1007/s00709-008-0004-9 Ter Halle A, 2006, ENVIRON SCI TECHNOL, V40, P2989, DOI 10.1021/es052266h Turkoglu S, 2007, MUTAT RES-GEN TOX EN, V626, P4, DOI 10.1016/j.mrgentox.2006.07.006 Voutsinas G, 1997, CELL BIOL INT, V21, P411, DOI 10.1006/cbir.1997.0171 Wichert R.A., 1999, P BCPC C WEEDS, V1-3, P105 WILSON JS, 1992, WEED TECHNOL, V6, P583Sta, Chaima Ledoigt, Gerard Ferjani, Ezzeddine Goupil, PascaleAcademic press inc elsevier scienceSan diegoLedoigt, G (reprint author), Univ Clermont Ferrand, Univ Blaise Pascal, UMR PIAF 547, BP 10448, F-63000 Clermont Ferrand, [email protected] genotoxicity of sulcotrione 2-(2-chloro-4-(methylsulfonyl)benzoyl)-1,3-cyclohexanedione, a selective triketonic herbicide was evaluated on Vicia faba seedlings in hydroponic culture conditions. Sulcotrione (10(-5), 10(-4) and 2 x 10(-4) M) treatments for 45 h, caused a dose dependent increase in micronuclei frequencies in root meristematic cells. Cytological analysis of root tips cells showed aneugenic effects of the sulcotrione on the plant root meristems. Sulcotrione induced chromosomal alterations at the lowest concentration used (10(-5) M) when incubated for 42 h, indicating the potent mutagenic effect of this element. This is the first report for the genotoxicity of such a sulcotrione herbicide. (C) 2012 Elsevier Inc. All rights reserved
2D Rayleigh-Taylor instability: Interfacial arc-length vs. deformation amplitude
No full textInternational audienceFluid interface instabilities are usually studied through the time evolution of the amplitude of deformation of the interface. While this approach is convenient, it often fails to fully describe the evolution of a deforming interface, especially when the interface cannot be represented as a single-valued function of a space coordinate. Here, we present new experimental data on Rayleigh-Taylor 2D instability for immiscible fluids, obtained through the use of magnetic levitation. We observe that new information can be retrieved by using an alternate metric to the amplitude, viz., the total arc-length of the interface (in 2D), or equivalently its total surface area (in 3D). In particular, we identify a master curve for the evolution of the arc-length over time, following three different regimes and on which all our data points fall. We conjecture that the exploration of such alternate metrics will yield equally promising results on a broad range of interface instabilities
Mechanically Generated Surface Chirality at the Nanoscale
No full textA substrate coated with an achiral polyimide alignment layer was scribed bidirectionally with the stylus of an atomic force microscope to create an easy axis for liquid crystal orientation. The resulting noncentrosymmetric topography resulted in a chiral surface that manifests itself at the molecular level. To show this unambiguously, a planar-aligned negative dielectric aniostropy achiral nematic liquid crystal was placed in contact with the surface and subjected to an electric field E. The nematic director was found to undergo an azimuthal rotation approximately linear in E. This so-called surface electroclinic effect is a signature of surface chirality and was not observed when the polyimide was treated for a centrosymmetric topography, and therefore was nonchiral
