Sample records for subject liquid crystalline

  1. Liquid crystalline dihydroazulene photoswitches

    DEFF Research Database (Denmark)

    Petersen, Anne Ugleholdt; Jevric, Martyn; Mandle, Richard J.


    A large selection of photochromic dihydroazulene (DHA) molecules incorporating various substituents at position 2 of the DHA core was prepared and investigated for their ability to form liquid crystalline phases. Incorporation of an octyloxy-substituted biphenyl substituent resulted in nematic...... to the DHA where the alignment is maintained. The systematic structural variation has revealed that a biaryl spacer between the DHA and the alkyl chain is needed for liquid crystallinity and that the one aromatic ring in the spacer cannot be substituted by a triazole. This work presents an important step...

  2. Liquid crystalline order in polymers

    CERN Document Server

    Blumstein, Alexandre


    Liquid Crystalline Order in Polymers examines the topic of liquid crystalline order in systems containing rigid synthetic macromolecular chains. Each chapter of the book provides a review of one important area of the field. Chapter 1 discusses scattering in polymer systems with liquid crystalline order. It also introduces the field of liquid crystals. Chapter 2 treats the origin of liquid crystalline order in macromolecules by describing the in-depth study of conformation of such macromolecules in their unassociated state. The chapters that follow describe successively the liquid crystalli

  3. Liquid-crystalline lanthanide complexes


    Binnemans, Koen


    The paper describes the recent developments in the field of liquid-crystalline lanthanide complexes. The role of trivalent lanthanide ions as the central metal ion in metallomesogens is considered. An outlook for the future is given.

  4. Crystalline Kitaev spin liquids (United States)

    Yamada, Masahiko G.; Dwivedi, Vatsal; Hermanns, Maria


    Frustrated magnetic systems exhibit many fascinating phases. Prime among them are quantum spin liquids, where the magnetic moments do not order even at zero temperature. A subclass of quantum spin liquids called Kitaev spin liquids are particularly interesting, because they are exactly solvable, can be realized in certain materials, and show a large variety of gapless and gapped phases. Here we show that nonsymmorphic symmetries can enrich spin liquid phases, such that the low-energy spinon degrees of freedom form three-dimensional Dirac cones or nodal chains. In addition, we suggest a realization of such Kitaev spin liquids in metal-organic frameworks.

  5. Liquid Crystalline Polymers (United States)


    Kunststoffe (German Plastics) 78(5):411-419. Calundann, G., M. Jaffe, R. S. Jones, and H. Yoon. 1988. Fibre Reinforcements for Composite Materials, A... Kunststoffe - German Plastics 77(10):1032-1035. 47 Williams, D. J. 1987. P. 405 in Nonlinear Optical Properties of Organic Molecules and Crystals, Vol. 1...crystalline acrylate. Makromol. Chem.-Macromol. Chem. Phys. 189(l):185-194. Browstow, W. 1988. Kunststoffe (German Plastics) 78:411. Clark, N. A. and

  6. Synthesis and characterization of thermotropic liquid crystalline ...

    Indian Academy of Sciences (India)

    The synthesised mesogens were characterized by different techniques including nuclear magnetic resonance and Fourier transform infrared spectroscopy. Liquid crystalline polymers (LCPs) were synthesised using pyromellitic dianhydride and 4-[(4-aminobenzylidene)amino]aniline or 4-aminophenyl-4-aminobenzoate.

  7. Nanoparticle-Liquid Crystalline Elastomer Composites


    Yan Ji; Terentjev, Eugene M.; Marshall, Jean E.


    Liquid crystalline elastomers (LCEs) exhibit a number of remarkable physical effects, including a uniquely high-stroke reversible mechanical actuation triggered by external stimuli. Fundamentally, all such stimuli affect the degree of liquid crystalline order in the polymer chains cross-linked into an elastic network. Heat and the resulting thermal actuation act by promoting entropic disorder, as does the addition of solvents. Photo-isomerization is another mechanism of actuation, reducing th...

  8. Thermally switched PDLC liquid-crystalline composites

    Directory of Open Access Journals (Sweden)

    Krzysztof Sułkowski


    Full Text Available The thermooptical properties of conventional polymer-dispersed nematic liquid crystals (PDLC composites in visual and near IR ranges have been studied. It has been confirmed that the composite film can be switched from the scattering milky state to the transparent state just by reaching a threshold temperature range, namely liquid crystal clearing phase transition to the isotropic one with satisfactory contrast ratio. The optical contrast and switching temperature range can be adjusted by the proper choice of the components of liquid crystalline mixture. This effect could be adopted for a construction of panes with “intelligent” heat transmission.[b]Keywords[/b]: materials engineering, liquid-crystalline composites, thermooptical effect

  9. Liquid crystalline order of carbon nanotubes (United States)

    Georgiev, Georgi; Ahlawat, Aditya; Mulkern, Brian; Doyle, Robert; Mongeau, Jennifer; Ogilvie, Alex


    Topological defects formed during phase transitions in liquid crystals provide a direct proof of the standard Cosmological model and are direct links to the Early Universe. On the other hand in Nanotechnology, carbon nanotubes can be manipulated and oriented directly by changing the liquid crystalline state of the nanotubes, in combination with organic liquid crystals. Currently there are no nano-assemblers, which makes the liquid crystal state of the nanotubes, one of the few ways of controlling them. We show the design of a fast and efficient polarized light ellipsometric system (a new modification of previous optical systems) that can provide fast quantitative real time measurements in two dimensions of the formation of topological defects in liquid crystals during phase transitions in lab settings. Our aim is to provide fundamental information about the formation of optically anisotropic structures in liquid crystals and the orientation of carbon nanotubes in electric field.

  10. Liquid Crystalline Semiconductors Materials, properties and applications

    CERN Document Server

    Kelly, Stephen; O'Neill, Mary


    This is an exciting stage in the development of organic electronics. It is no longer an area of purely academic interest as increasingly real applications are being developed, some of which are beginning to come on-stream. Areas that have already been commercially developed or which are under intensive development include organic light emitting diodes (for flat panel displays and solid state lighting), organic photovoltaic cells, organic thin film transistors (for smart tags and flat panel displays) and sensors. Within the family of organic electronic materials, liquid crystals are relative newcomers. The first electronically conducting liquid crystals were reported in 1988 but already a substantial literature has developed. The advantage of liquid crystalline semiconductors is that they have the easy processability of amorphous and polymeric semiconductors but they usually have higher charge carrier mobilities. Their mobilities do not reach the levels seen in crystalline organics but they circumvent all of t...

  11. Thermotropic liquid crystalline polyesters derived from 2-chloro ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 129; Issue 9. Thermotropic liquid crystalline polyesters derived from 2-chloro ... These polyesters exhibited thermotropic liquid crystalline behavior and showed nematic texture except decamethylene spacer. Decamethylene spacer based polyester showed marble ...

  12. Stable liquid crystalline phases of colloidally dispersed exfoliated layered niobates. (United States)

    Nakato, Teruyuki; Miyamoto, Nobuyoshi; Harada, Akiko


    Colloidally dispersed niobium oxide nanosheets obtained by exfoliation of layered niobates HNb(3)O(8) and HTiNbO(5) formed stable liquid crystalline phases; their liquid crystallinity was dependent on the niobate species exfoliated.

  13. Synthesis of New Liquid Crystalline Diglycidyl Ethers

    Directory of Open Access Journals (Sweden)

    Issam Ahmed Mohammed


    Full Text Available The phenolic Schiff bases I–VI were synthesized by condensation reactions between various diamines, namely o-dianisidine, o-tolidine and ethylenediamine with vanillin or p-hydroxybenzaldehyde and subsequent reactions between these phenolic Schiff bases and epichlorohydrin to produce new diglycidyl ethers Ia–VIa. The structures of these compounds were confirmed by CHN, FT-IR, 1H-NMR, and 13C-NMR spectroscopy. Their thermotropic liquid crystalline behavior was studied using differential scanning calorimetry (DSC and polarizing optical microscopy (POM. All the diglycidyl ethers prepared exhibit nematic mesophases, except for Va and VIa, which did not show any transition mesophases, but simply flow to liquids.

  14. Templating gold nanorods with liquid crystalline DNA (United States)

    De Sio, Luciano; Annesi, Ferdinanda; Placido, Tiziana; Comparelli, Roberto; Bruno, Vincenzo; Pane, Alfredo; Palermo, Giovanna; Curri, Maria Lucia; Umeton, Cesare; Bartolino, Roberto


    A liquid crystalline, negatively charged, whole-genome DNA is exploited to organize positively charged gold nanorods (GNRs) by means of electrostatic interaction. A mesoscopic alignment of the composite system along a preferred direction is obtained by casting a droplet of the DNA-nanorods solution onto an untreated glass substrate. Gel electrophoresis analysis enables evaluating the effective electric charge of the system, thus minimizing the DNA fragmentation. Polarized optical microscopy, combined with transmission and scanning electron microscopy, shows that, up to 20% in weight of GNR solution, the system exhibits both a long range order, induced by the liquid crystalline phase of the DNA, and a nanoscale organization, due to the DNA self-assembly. These evidences are confirmed by a polarized spectral analysis, which also points out that the optical properties of GNRs strongly depend on the polarization of the impinging probe light. The capability to organize plasmonic nanoparticles by means of DNA material represents a significant advance towards the realization of life science inspired optical materials.

  15. Nanoparticle-Liquid Crystalline Elastomer Composites

    Directory of Open Access Journals (Sweden)

    Yan Ji


    Full Text Available Liquid crystalline elastomers (LCEs exhibit a number of remarkable physical effects, including a uniquely high-stroke reversible mechanical actuation triggered by external stimuli. Fundamentally, all such stimuli affect the degree of liquid crystalline order in the polymer chains cross-linked into an elastic network. Heat and the resulting thermal actuation act by promoting entropic disorder, as does the addition of solvents. Photo-isomerization is another mechanism of actuation, reducing the orientational order by diminishing the fraction of active rod-like mesogenic units, mostly studied for azobenzene derivatives incorporated into the LCE composition. Embedding nanoparticles provides a new, promising strategy to add functionality to LCEs and ultimately enhance their performance as sensors and actuators. The motivation for the combination of nanoparticles with LCEs is to provide better-controlled actuation stimuli, such as electric and magnetic fields, and broad-spectrum light, by selecting and configuring the appropriate nanoparticles in the LCE matrix. Here we give an overview of recent advances in this area with a focus on preparation, physical properties and actuation performance of the resultant nanocomposites.

  16. Bicontinuous cubic liquid crystalline nanoparticles for oral delivery of Doxorubicin

    DEFF Research Database (Denmark)

    Swarnakar, Nitin K; Thanki, Kaushik; Jain, Sanyog


    PURPOSE: The present study explores the potential of bicontinous cubic liquid crystalline nanoparticles (LCNPs) for improving therapeutic potential of doxorubicin. METHODS: Phytantriol based Dox-LCNPs were prepared using hydrotrope method, optimized for various formulation components, process var...

  17. Liquid crystalline thermosetting polymers as protective coatings for aerospace

    NARCIS (Netherlands)

    Guerriero, G.L.


    Environmental regulations are driving the development of new aerospace coating systems, mainly to eliminate chromates and reduce volatile organic compound (VOC) emissions. Among the various potential options for new coating materials, liquid crystalline polymers (LCPs) are attractive due to their

  18. Liquid crystalline epoxy nanocomposite material for dental application. (United States)

    Tai, Yun-Yuan; Hsu, Sheng-Hao; Chen, Rung-Shu; Su, Wei-Fang; Chen, Min-Huey


    Novel liquid crystalline epoxy nanocomposites, which exhibit reduced polymerization shrinkage and effectively bond to tooth structures, can be applied in esthetic dentistry, including core and post systems, direct and indirect restorations, and dental brackets. The purposes of this study were to investigate the properties of liquid crystalline epoxy nanocomposites including biocompatibility, microhardness, and frictional forces of bracket-like blocks with different filler contents for further clinical applications. In this study, we evaluated liquid crystalline epoxy nanocomposite materials that exhibited various filler contents, by assessing their cell activity performance using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and their microhardness with or without thermocycling. We also evaluated the frictional force between bracket-like duplicates and commercially available esthetic bracket systems using Instron 5566. The liquid crystalline epoxy nanocomposite materials showed good biocompatibility. The materials having high filler content demonstrated greater microhardness compared with commercially available bracket materials, before and after the thermocycling treatment. Thus, manufacturing processes are important to reduce frictional force experienced by orthodontic brackets. The microhardness of the bracket-like blocks made by our new material is superior to the commercially available brackets, even after thermocycling. Our results indicate that the evaluated liquid crystalline epoxy nanocomposite materials are of an appropriate quality for application in dental core and post systems and in various restorations. By applying technology to refine manufacturing processes, these new materials could also be used to fabricate esthetic brackets for orthodontic treatment. Copyright © 2014. Published by Elsevier B.V.

  19. Liquid crystallinity driven highly aligned large graphene oxide composites

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyung Eun; Oh, Jung Jae; Yun, Taeyeong [Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon 305-701 (Korea, Republic of); Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701 (Korea, Republic of); Kim, Sang Ouk, E-mail: [Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon 305-701 (Korea, Republic of); Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701 (Korea, Republic of)


    Graphene is an emerging graphitic carbon materials, consisting of sp{sup 2} hybridized two dimensinal honeycomb structure. It has been widely studied to incorporate graphene with polymer to utilize unique property of graphene and reinforce electrical, mechanical and thermal property of polymer. In composite materials, orientation control of graphene significantly influences the property of composite. Until now, a few method has been developed for orientation control of graphene within polymer matrix. Here, we demonstrate facile fabrication of high aligned large graphene oxide (LGO) composites in polydimethylsiloxane (PDMS) matrix exploiting liquid crystallinity. Liquid crystalline aqueous dispersion of LGO is parallel oriented within flat confinement geometry. Freeze-drying of the aligned LGO dispersion and subsequent infiltration with PDMS produce highly aligned LGO/PDMS composites. Owing to the large shape anisotropy of LGO, liquid crystalline alignment occurred at low concentration of 2 mg/ml in aqueous dispersion, which leads to the 0.2 wt% LGO loaded composites. - Graphical abstract: Liquid crystalline LGO aqueous dispersions are spontaneous parallel aligned between geometric confinement for highly aligned LGO/polymer composite fabrication. - Highlights: • A simple fabrication method for highly aligned LGO/PDMS composites is proposed. • LGO aqueous dispersion shows nematic liquid crystalline phase at 0.8 mg/ml. • In nematic phase, LGO flakes are highly aligned by geometric confinement. • Infiltration of PDMS into freeze-dried LGO allows highly aligned LGO/PDMS composites.

  20. Novel Colloidal and Dynamic Interfacial Phenomena in Liquid Crystalline Systems (United States)


    planar interfaces of LC films, and that the repulsive interaction can be overcome by splay attraction of the colloids to the boojums of the LC droplets...of magnitude with the geometry of the LC (droplet versus slab), supporting the hypothesis that topological defects in the LC mediate the response of...crystalline solvents will be discussed. In this example, the anisotropic elastic properties of the liquid crystalline phase, as well as topological

  1. A liquid crystalline chirality balance for vapours

    National Research Council Canada - National Science Library

    Ohzono, Takuya; Yamamoto, Takahiro; Fukuda, Jun-ichi


    ... in a periodic microstructure of a nematic liquid crystal confined in open microchannels. This microstructure is accompanied by a topological line defect of a zigzag form with equal lengths of 'zig' and 'zag...

  2. Photoswitching of Dihydroazulene Derivatives in Liquid-Crystalline Host Systems

    DEFF Research Database (Denmark)

    Petersen, Anne Ugleholdt; Jevric, Martyn; Mandle, Richard J.


    Photoswitches and dyes in the liquid-crystalline nematic phase have the potential for use in a wide range of applications. A large order parameter is desirable to maximize the change in properties induced by an external stimulus. A set of photochromic and nonphotochromic dyes were investigated...... for these applications. It was found that a bent-shaped 7-substituted dihydroazulene (DHA) photoswitch exhibited liquid-crystalline properties. Further investigation demonstrated that this material actually followed two distinct reaction pathways on heating, to a deactivated form by a 1,5-sigmatropic shift...

  3. Effects of alkaline or liquid-ammonia treatment on crystalline cellulose: changes in crystalline structure and effects on enzymatic digestibility

    Directory of Open Access Journals (Sweden)

    Himmel Michael E


    Full Text Available Abstract Background In converting biomass to bioethanol, pretreatment is a key step intended to render cellulose more amenable and accessible to cellulase enzymes and thus increase glucose yields. In this study, four cellulose samples with different degrees of polymerization and crystallinity indexes were subjected to aqueous sodium hydroxide and anhydrous liquid ammonia treatments. The effects of the treatments on cellulose crystalline structure were studied, in addition to the effects on the digestibility of the celluloses by a cellulase complex. Results From X-ray diffractograms and nuclear magnetic resonance spectra, it was revealed that treatment with liquid ammonia produced the cellulose IIII allomorph; however, crystallinity depended on treatment conditions. Treatment at a low temperature (25°C resulted in a less crystalline product, whereas treatment at elevated temperatures (130°C or 140°C gave a more crystalline product. Treatment of cellulose I with aqueous sodium hydroxide (16.5 percent by weight resulted in formation of cellulose II, but also produced a much less crystalline cellulose. The relative digestibilities of the different cellulose allomorphs were tested by exposing the treated and untreated cellulose samples to a commercial enzyme mixture (Genencor-Danisco; GC 220. The digestibility results showed that the starting cellulose I samples were the least digestible (except for corn stover cellulose, which had a high amorphous content. Treatment with sodium hydroxide produced the most digestible cellulose, followed by treatment with liquid ammonia at a low temperature. Factor analysis indicated that initial rates of digestion (up to 24 hours were most strongly correlated with amorphous content. Correlation of allomorph type with digestibility was weak, but was strongest with cellulose conversion at later times. The cellulose IIII samples produced at higher temperatures had comparable crystallinities to the initial cellulose I

  4. Controlling the morphology of side chain liquid crystalline block copolymer thin films through variations in liquid crystalline content. (United States)

    Verploegen, Eric; Zhang, Tejia; Jung, Yeon Sik; Ross, Caroline; Hammond, Paula T


    In this paper, we describe methods for manipulating the morphology of side-chain liquid crystalline block copolymers through variations in the liquid crystalline content. By systematically controlling the covalent attachment of side chain liquid crystals to a block copolymer (BCP) backbone, the morphology of both the liquid crystalline (LC) mesophase and the phase-segregated BCP microstructures can be precisely manipulated. Increases in LC functionalization lead to stronger preferences for the anchoring of the LC mesophase relative to the substrate and the intermaterial dividing surface. By manipulating the strength of these interactions, the arrangement and ordering of the ultrathin film block copolymer nanostructures can be controlled, yielding a range of morphologies that includes perpendicular and parallel cylinders, as well as both perpendicular and parallel lamellae. Additionally, we demonstrate the utilization of selective etching to create a nanoporous liquid crystalline polymer thin film. The unique control over the orientation and order of the self-assembled morphologies with respect to the substrate will allow for the custom design of thin films for specific nanopatterning applications without manipulation of the surface chemistry or the application of external fields.

  5. Bioinspired actuated adhesive patterns of liquid crystalline elastomers. (United States)

    Cui, Jiaxi; Drotlef, Dirk-Michael; Larraza, Iñigo; Fernández-Blázquez, Juan P; Boesel, Luciano F; Ohm, Christian; Mezger, Markus; Zentel, Rudolf; del Campo, Aránzazu


    Gecko-inspired arrays of micropillars made of a liquid crystalline elastomer display thermoswitchable adhesive behavior as a consequence of elongation changes caused by reorientation of the mesogens at the nematic-isotropic (N-I) phase transition. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Thermotropic liquid crystalline polyesters derived from bis-(4 ...

    Indian Academy of Sciences (India)


    melt.1,2 Researchers concentrate on modifing the structure and properties of liquid crystalline aromatic polymers.3–5 ... desirable to lower the melting temperature for processing through conventional methods. This could be .... magnetic stirrer and kept in ice bath and stirred till it dis- solved completely. Alcoholic potassium ...

  7. In-situ photopolymerization of oriented liquid-crystalline acrylates

    NARCIS (Netherlands)

    Broer, Dirk Jan


    The scope of this thesis concerns a new method to produce oriented polymers by the in-situ photopolymerization of oriented liquid-crystalline acrylates. The desired macroscopic molecular order is already accomplished in the monomeric state prior to the polymerization. ... Zie: Summary

  8. Rotational reorganization of doped cholesteric liquid crystalline films

    NARCIS (Netherlands)

    Eelkema, R.; M. Pollard, M.; Katsonis, N.; Vicario, J.; J. Broer, D.; Feringa, B.L.


    In this paper an unprecedented rotational reorganization of cholesteric liquid crystalline films is described. This rotational reorganization results from the conversion of a chiral molecular motor dopant to an isomer with a different helical twisting power, leading to a change in the cholesteric

  9. Fluorine-containing triphenylenes. Liquid crystalline properties and surface ordering

    NARCIS (Netherlands)

    Umesh, C.P.; Marcelis, A.T.M.; Zuilhof, H.


    The synthesis and liquid crystalline properties of two novel series of triphenylenes with 4 or 5 pentafuoropentyloxy tails and 1 or 2 alkoxy tails of varying length are reported. All compounds form wide-range hexagonal columnar phases. The isotropisation temperatures and the corresponding enthalpy

  10. Banana-shaped side chain liquid crystalline siloxanes

    NARCIS (Netherlands)

    Achten, R.; Koudijs, A.; Giesbers, M.; Reddy, R.A.; Verhulst, T.; Tschierske, C.; Marcelis, A.T.M.; Sudhölter, E.J.R.


    Eight banana-shaped side chain liquid crystalline oligomers and polymers have been synthesized by hydrosilylation of vinyl-terminated bent-core mesogens with trimethylsilyl-terminated siloxanes. The synthesized oligomers and polymers, and their olefinic precursors, were investigated by polarizing

  11. Well-defined side-chain liquid-crystalline polysiloxanes

    NARCIS (Netherlands)

    Hempenius, Mark A.; Lammertink, Rob G.H.; Vancso, Gyula J.


    A route to well-defined side-chain liquid-crystalline polysiloxanes (ratio of weight-to number-average molar masses Mw/Mn < 1.2 is reported. Anionic ring-opening polymerization of pentamethylvinylcyclotrisiloxane yielded a poly(dimethylsiloxane-co-methylvinylsiloxane) backbone. A flexible disiloxane

  12. Multifunctional materials exhibiting spin crossover and liquid-crystalline properties

    Energy Technology Data Exchange (ETDEWEB)

    Seredyuk, M. [Johannes-Gutenberg-Universitaet, Institut fuer Anorganische und Analystiche Chemie (Germany); Gaspar, Ana B. [Universitat de Valencia, Edifici de Instituts de Paterna, Institut de Ciencia Molecular/Departament de Quimica Inorganica (Spain); Ksenofontov, V., E-mail:; Reiman, S. [Johannes-Gutenberg-Universitaet, Institut fuer Anorganische und Analystiche Chemie (Germany); Galyametdinov, Y. [Russian Academy of Science, Kazan Physical technical Institute (Russian Federation); Haase, W. [Darmstad University of Technology, Institute of Physical Chemistry (Germany); Rentschler, E.; Guetlich, P. [Johannes-Gutenberg-Universitaet, Institut fuer Anorganische und Analystiche Chemie (Germany)


    The physical characterization of a new class of Fe(II) multifunctional SCO materials exhibiting spin crossover and liquid crystalline properties in the room temperatures region is reported. Moessbauer spectroscopy, magnetic, differential scanning calorimetry (DSC), X-ray powder diffraction (XRD) and optical polarizing microscopy studies have been performed on such materials.

  13. Lyotropic liquid crystalline nanoparticles of CoQ10

    DEFF Research Database (Denmark)

    Swarnakar, Nitin K; Thanki, Kaushik; Jain, Sanyog


    The present investigation reports implications of the lipase digestibility of lyotropic liquid crystalline nanoparticles (LCNPs) on the oral bioavailability, in vivo antioxidant potential, and in vitro-in vivo relationship (IVIVR) of CoQ10 loaded LCNPs prepared from glyceryl monooleate (GLCQ...

  14. Liquid dynamics in partially crystalline glycerol

    DEFF Research Database (Denmark)

    Sanz, Alejandro; Niss, Kristine


    We present a dielectric study on the dynamics of supercooled glycerol during crystallization. We explore the transformation into a solid phase in real time by monitoring the temporal evolution of the amplitude of the dielectric signal. Neither the initial nucleation nor the crystal growth...... influences the liquid dynamics visibly. For one of the samples studied, a tiny fraction of glycerol remained in the disordered state after the end of the transition. We examined the nature of the relaxation in this frustrated crystal and find that it is virtually identical to the bulk dynamics. In addition...

  15. Liquid crystalline fiber optic colorimeter for hydrostatic pressure measurement (United States)

    Wolinski, Tomasz R.; Bajdecki, Waldemar K.; Domanski, Andrzej W.; Karpierz, Miroslaw A.; Konopka, Witold; Nasilowski, T.; Sierakowski, Marek W.; Swillo, Marcin; Dabrowski, Roman S.; Nowinowski-Kruszelnicki, Edward; Wasowski, Janusz


    This paper presents results of tests performed on a fiber optic system of liquid crystalline transducer for hydrostatic pressure monitoring based on properties of colorimetry. The system employs pressure-induced deformations occurring in liquid crystalline (LC) cells configured in a homogeneous Frederiks geometry. The sensor is compared of a round LC cell placed inside a specially designed pressure chamber. As a light source we used a typical diode operating at red wavelength and modulated using standard techniques. The pressure transducer was connected to a computer with a specially designed interface built on the bas of advanced ADAM modules. Results indicate that the system offers high response to pressure with reduced temperature sensitivity and, depending on the LC cell used, can be adjusted for monitoring of low hydrostatic pressures up to 6 MPa. These studies have demonstrated the feasibility of fiber optic liquid crystal colorimeter for hydrostatic pressure sensing specially dedicated to pipe- lines, mining instrumentation, and process-control technologies.

  16. Liquid ethanol simulated on crystalline alpha alumina. (United States)

    Phan, Anh; Cole, David R; Striolo, Alberto


    Equilibrium molecular dynamics simulations were employed to investigate the structural properties of interfacial liquid ethanol on two alumina surfaces-the (0001) and the (11[overline]02) terminations of α-Al2O3-both described using the CLAYFF force field. The resultant atomic density profiles show that ethanol molecules in the first monolayer are well ordered and that their distribution depends on the surface OH groups. A pronounced dipolar orientation is found for the ethanol molecules in the first layer and also, although to a smaller extent, among the ethanol molecules in the second molecular layer. The orientational distribution predicted for the methyl group of ethanol on α-Al2O3 (11[overline]02) is consistent with that observed experimentally by Shen and co-workers. The orientation of molecules in the second layer is opposite compared to that found in the first adsorbed molecular layer. Our simulations show long residence times and slowly decaying reorientation autocorrelation functions for ethanol molecules in the first adsorbed layer, suggesting that within the first adsorbed layer ethanol molecules are strongly coordinated with both α-Al2O3 (0001) and α-Al2O3 (11[overline]02) surfaces. Analysis of the hydrogen bond network confirms that preferential surface-ethanol interactions are responsible for such observations.

  17. Liquid crystalline polymer electrolyte membranes with ion gating properties (United States)

    Cao, Jinwei; Piedrahita, Camilo; Koterasawa, Kagami; Freedman, Abegel; Martins, Juliana; Kyu, Thein; Pugh, Coleen; Adachi, Kaoru; Tsukahara, Yasuhisa

    Polymer electrolyte membranes (PEMs) with ion conducting channels have been fabricated via photo-polymerization of liquid crystalline monomers, synthesized in our laboratory. The monomers consist of polyethylene glycol segments as the ion conduction medium and photoactive azobenzene mesogen. Guided by the phase diagram of azobenzene LC and nematic LC, ion conducting channels are formed in the liquid crystalline phases. Ionic conductivities of the azobenzene LCs were measured in trans-state and cis-state using AC impedance spectroscopy. By applying UV or visible light, the opening/closing of ion channels may be controlled through rapid trans-cis isomerization of azobenzene mesogen by light irradiation. Therefore, the ion conduction ability of the PEMs can be optically controlled, affording ion gating capability of the PEMs. These PEMs can act as the ion conducting channels on cell membranes and, therefore, may be used to construct artificial neurons. Supported by NSF-DMR 1502543.

  18. Liquid Crystalline Network Composites Reinforced by Silica Nanoparticles

    Directory of Open Access Journals (Sweden)

    Zhen Li


    Full Text Available Liquid crystalline networks (LCNs are a class of polymers, which are able to produce mechanical actuation in response to external stimuli. Recent creation of LCNs with exchangeable links (xLCNs makes LCNs easy moldable. As the xLCNs need to be shaped at a high temperature, it is important to enhance their thermal and mechanical properties. In this paper, a series of xLCNs/SiO2 composites containing 1%–7% SiO2 nanoparitcles (SNP were prepared and their thermal and mechanical properties were examined. The results show that xLCNs/SNP composites have lower liquid crystalline-isotropic phase transition temperature and higher decomposition temperature than pure LCN. The tensile strength and the elongation at break of xLCNs at high temperatures were also enhanced due to the addition of SNPs.

  19. Dendritic liquid-crystalline fullerene–ferrocene dyads


    Campidelli, Stéphane; Pérez, Laura; Rodríguez-López Julián; Barberá, Joaquín; Langa, Fernando; Deschenaux, Robert


    First- and second-generation ferrocene-based dendrimers, fullerene and a second-generation liquid-crystalline poly(arylester) dendrimer carrying four cyanobiphenyl units were assembled to elaborate polyfunctional materials displaying mesomorphic and electronic properties. The targeted compounds gave rise to enantiotropic smectic A phases and organized into bilayer structures within the smectic layers. Cyclic voltammetry investigations revealed oxidation and reduction processes in agreement wi...

  20. Liquid crystalline epoxy nanocomposite material for dental application

    Directory of Open Access Journals (Sweden)

    Yun-Yuan Tai


    Conclusion: The microhardness of the bracket-like blocks made by our new material is superior to the commercially available brackets, even after thermocycling. Our results indicate that the evaluated liquid crystalline epoxy nanocomposite materials are of an appropriate quality for application in dental core and post systems and in various restorations. By applying technology to refine manufacturing processes, these new materials could also be used to fabricate esthetic brackets for orthodontic treatment.

  1. Side-chain liquid crystalline polyesters for optical information storage

    DEFF Research Database (Denmark)

    Ramanujam, P.S.; Holme, Christian; Hvilsted, Søren


    and holographic storage in one particular polyester are described in detail and polarized Fourier transform infrared spectroscopic data complementing the optical data are presented. Optical and atomic force microscope investigations point to a laser-induced aggregation as responsible for permanent optical storage.......Azobenzene side-chain liquid crystalline polyester structures suitable for permanent optical storage are described. The synthesis and characterization of the polyesters together with differential scanning calorimetry and X-ray investigations are discussed. Optical anisotropic investigations...

  2. Towards liquid crystalline elastomer optically tunable photonic microstructures (United States)

    Nocentini, S.; Martella, D.; Parmeggiani, C.; Zanotto, S.; Wiersma, D. S.


    In this paper we investigate the potentials of liquid crystalline elastomer microstructures for the realization of optically tunable photonic microstructures. While certain limitations regarding the compromise between feature size and structure warping have been observed, it turns out that the simultaneous presence of a refractive index tuning effect and of a shape tuning effect intrinsic to the LCE material can be harnessed to design tunable photonic devices with unique behavior.

  3. Birefringence and DNA Condensation of Liquid Crystalline Chromosomes ▿ (United States)

    Chow, Man H.; Yan, Kosmo T. H.; Bennett, Michael J.; Wong, Joseph T. Y.


    DNA can self-assemble in vitro into several liquid crystalline phases at high concentrations. The largest known genomes are encoded by the cholesteric liquid crystalline chromosomes (LCCs) of the dinoflagellates, a diverse group of protists related to the malarial parasites. Very little is known about how the liquid crystalline packaging strategy is employed to organize these genomes, the largest among living eukaryotes—up to 80 times the size of the human genome. Comparative measurements using a semiautomatic polarizing microscope demonstrated that there is a large variation in the birefringence, an optical property of anisotropic materials, of the chromosomes from different dinoflagellate species, despite their apparently similar ultrastructural patterns of bands and arches. There is a large variation in the chromosomal arrangements in the nuclei and individual karyotypes. Our data suggest that both macroscopic and ultrastructural arrangements affect the apparent birefringence of the liquid crystalline chromosomes. Positive correlations are demonstrated for the first time between the level of absolute retardance and both the DNA content and the observed helical pitch measured from transmission electron microscopy (TEM) photomicrographs. Experiments that induced disassembly of the chromosomes revealed multiple orders of organization in the dinoflagellate chromosomes. With the low protein-to-DNA ratio, we propose that a highly regulated use of entropy-driven force must be involved in the assembly of these LCCs. Knowledge of the mechanism of packaging and arranging these largest known DNAs into different shapes and different formats in the nuclei would be of great value in the use of DNA as nanostructural material. PMID:20400466

  4. Effects of molecular architecture on liquid crystalline thermosets (United States)

    Gavrin, Arthur John

    This work incorporates three studies on the influence of molecular architecture on liquid crystalline phase transitions, physical transformations, and thermal stability for acetylene functionalized liquid crystalline thermosets (LCTs). The first study focuses on synthesis and liquid crystalline phase characterization of acetylene functionalized LCTs. The second examines architecture's influence on liquid crystalline phase transitions and physical transformations that occur during isothermal curing of LCTs. The third deals with architecture and the thermal stability of the uncured and fully cured thermosets. Two homologous series of LCT monomers, differing in mesogen length, were synthesized: with monomers composed of an aromatic mesogen based on either hydroquinone (nHQ) or biphenol (nBP), end-capped with acetylene functional groups, and terminated with flexible alkyl chains of 3 to 8 carbons in length. The nHQ monomers melt and clear at lower temperatures than the nBP series. The monomers were characterized with differential scanning calorimetry (DSC), dynamic thermogravimetric analysis (TGA), and cross-polarized optical microscopy (POM). The monomers displayed liquid crystalline behavior similar to that of a related small molecule liquid crystal series. A related fully aromatic monomer was also synthesized (PEBP). It possesses higher melting and clearing temperatures, displays only a nematic phase, and has higher thermal stability. The monomers of the two series were isothermally cured in a rheometer. Gelation times were determined from the shear moduli crossover point. Both series display an odd-even effect for gel times, even though the entire nHQ series is isotropic during the isothermal cure. This is the first time such behavior has been seen for an unordered system. From POM, the monomers lose their molecular ordering during initial chain extension, but may regain some order at later extents of curing if at low enough temperatures. TGA and isothermal

  5. Dry Powder Precursors of Cubic Liquid Crystalline Nanoparticles (cubosomes) (United States)

    Spicer, Patrick T.; Small, William B.; Small, William B.; Lynch, Matthew L.; Burns, Janet L.


    Cubosomes are dispersed nanostructured particles of cubic phase liquid crystal that have stimulated significant research interest because of their potential for application in controlled-release and drug delivery. Despite the interest, cubosomes can be difficult to fabricate and stabilize with current methods. Most of the current work is limited to liquid phase processes involving high shear dispersion of bulk cubic liquid crystalline material into sub-micron particles, limiting application flexibility. In this work, two types of dry powder cubosome precursors are produced by spray-drying: (1) starch-encapsulated monoolein is produced by spray-drying a dispersion of cubic liquid crystalline particles in an aqueous starch solution and (2) dextran-encapsulated monoolein is produced by spray-drying an emulsion formed by the ethanol-dextran-monoolein-water system. The encapsulants are used to decrease powder cohesion during drying and to act as a soluble colloidal stabilizer upon hydration of the powders. Both powders are shown to form (on average) 0.6 μm colloidally-stable cubosomes upon addition to water. However, the starch powders have a broader particle size distribution than the dextran powders because of the relative ease of spraying emulsions versus dispersions. The developed processes enable the production of nanostructured cubosomes by end-users rather than just specialized researchers and allow tailoring of the surface state of the cubosomes for broader application.

  6. Quantitative Analysis of Matrine in Liquid Crystalline Nanoparticles by HPLC

    Directory of Open Access Journals (Sweden)

    Xinsheng Peng


    Full Text Available A reversed-phase high-performance liquid chromatographic method has been developed to quantitatively determine matrine in liquid crystal nanoparticles. The chromatographic method is carried out using an isocratic system. The mobile phase was composed of methanol-PBS(pH6.8-triethylamine (50 : 50 : 0.1% with a flow rate of 1 mL/min with SPD-20A UV/vis detector and the detection wavelength was at 220 nm. The linearity of matrine is in the range of 1.6 to 200.0 μg/mL. The regression equation is y=10706x-2959 (R2=1.0. The average recovery is 101.7%; RSD=2.22%  (n=9. This method provides a simple and accurate strategy to determine matrine in liquid crystalline nanoparticle.

  7. Photoorientation of a liquid crystalline polyester with azobenzene side groups

    DEFF Research Database (Denmark)

    Zebger, I; Rutloh, M; Hoffmann, U


    The photoorientation process in a polyester with 4-cyano-4'-alkoxyazobenzene side group and long methylene spacers in the side and the main-chain was studied as a function of irradiation with linearly polarized light of 488 nm under systematic variation of the power density and temperature....... This model polymer is characterized by liquid crystallinity (g 24 S-X 26 S-A 34 n 47 i) and a strong aggregation tendency. The photoorientation is cooperative, i.e., the orientation of the photochromic side group induces the alignment of the ester unit (which is a part of the main-chain) and both methylene...

  8. A Molecular View of Liquid Crystalline Elastomers and Gels (United States)

    de Pablo, Juan


    A combination of Monte Carlo and molecular dynamics simulations is used to examine the order-disorder transitions that arise in model liquid crystalline elastomers and colloidal gels as a function of concentration and strain, respectively. Two models are considered. In the first, a lattice model is used to represent a colloidal gel of nematogens and nanoparticles. In the second, a cross-linked elastomer of Gay-Berne mesogens is adopted to examine the order-disroder transition that arises as a function of strain. The results of simulations are compared to those of recent experiments for these two classes of systems.

  9. Thermal degradation of polymer systems having liquid crystalline oligoester segment

    Directory of Open Access Journals (Sweden)

    Renato Matroniani

    Full Text Available Abstract Block copolymers and blends comprised by liquid crystalline oligoester and polystyrene were prepared and their thermal stability were characterized by thermogravimetric analysis (TGA. The samples have shown three main decomposition temperatures due to (1 lost of flexible chain and decomposition of mesogenic segment, (2 decomposition of polystyrene and (3 final decomposition of oligoester rigid segment. Both copolymers and polymer blends presented lower thermal stability compared to polystyrene and oligoester. The residual mass after heating at 600 °C in copolymers and polymer blends were lower than those found in the oligoesters. A degradative process of aromatic segments of oligoester induced by decomposition of polystyrene is suggested.

  10. Optical pendulum generator based on photomechanical liquid-crystalline actuators. (United States)

    Tang, Rong; Liu, Ziyi; Xu, Dandan; Liu, Jian; Yu, Li; Yu, Haifeng


    For converting light energy into electricity, an optical pendulum generator was designed by combining photomechanical movement of liquid-crystalline actuator (LCA) with Faraday's law of electromagnetic induction. Bilayer cantilever actuators were first fabricated with LDPE and LCA. Their photomechanical movement drove the attached copper coils to cut magnetic line of force generating electricity. The output electricity was proportional to the changing rate of the magnetic flux, which was greatly influenced by light intensity, film thickness, and sample size. Continuous electrical output was also achieved. This simple strategy may expand applications of photoactive materials in the capture and storage of light energy.

  11. Liquid water in the domain of cubic crystalline ice Ic (United States)

    Jenniskens, P.; Banham, S. F.; Blake, D. F.; McCoustra, M. R.


    Vapor-deposited amorphous water ice when warmed above the glass transition temperature (120-140 K), is a viscous liquid which exhibits a viscosity vs temperature relationship different from that of liquid water at room temperature. New studies of thin water ice films now demonstrate that viscous liquid water persists in the temperature range 140-210 K. where it coexists with cubic crystalline ice. The liquid character of amorphous water above the glass transition is demonstrated by (1) changes in the morphology of water ice films on a nonwetting surface observed in transmission electron microscopy (TEM) at around 175 K during slow warming, (2) changes in the binding energy of water molecules measured in temperature programmed desorption (TPD) studies, and (3) changes in the shape of the 3.07 micrometers absorption band observed in grazing angle reflection-absorption infrared spectroscopy (RAIRS) during annealing at high temperature. whereby the decreased roughness of the water surface is thought to cause changes in the selection rules for the excitation of O-H stretch vibrations. Because it is present over such a wide range of temperatures, we propose that this form of liquid water is a common material in nature. where it is expected to exist in the subsurface layers of comets and on the surfaces of some planets and satellites.

  12. Computer simulation of confined and flexoelectric liquid crystalline systems

    CERN Document Server

    Barmes, F


    In this Thesis, systems of confined and flexoelectric liquid crystal systems have been studied using molecular computer simulations. The aim of this work was to provide a molecular model of a bistable display cell in which switching is induced through the application of directional electric field pulses. In the first part of this Thesis, the study of confined systems of liquid crystalline particles has been addressed. Computation of the anchoring phase diagrams for three different surface interaction models showed that the hard needle wall and rod-surface potentials induce both planar and homeotropic alignment separated by a bistability region, this being stronger and wider for the rod-surface varant. The results obtained using the rod-sphere surface model, in contrast, showed that tilled surface arrangements can be induced by surface absorption mechanisms. Equivalent studies of hybrid anchored systems showed that a bend director structure can be obtained in a slab with monostable homeotropic anchoring at the...

  13. Tautomeric behavior of some azoquinoline dyes in liquid and liquid crystalline media. (United States)

    Ghanadzadeh Gilani, A; Moradi, E; Binay, S; Moghadam, M


    The absorption spectra of three azoquinolin-8-ol derivatives (o-, m-, p-cyano hydroxy azoquinolin dyes) were investigated in liquid and liquid crystalline solutions as a function of the solvent polarity. The spectral data of the dyes were compared in both ordinary liquid solvents and liquid crystalline media. Analysis of the spectral data was used to determine the azo and hydrazone forms in both the environments. The spectral shifts were correlated by Kamlet-Taft and Katritzky multi-parameter polarity scales. For the azoquinoline dyes, the azo form is almost entirely dominated in polar anisotropic hosts. In contrast, the compounds remain dominantly in hydrazone form in some polar solvents such as DMF. The polarized absorption spectra of the compounds in the anisotropic media were measured and their degree of anisotropies was determined. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. Liquid-Crystalline Ionic Liquids as Ordered Reaction Media for the Diels-Alder Reaction. (United States)

    Bruce, Duncan W; Gao, Yanan; Canongia Lopes, José Nuno; Shimizu, Karina; Slattery, John M


    Liquid-crystalline ionic liquids (LCILs) are ordered materials that have untapped potential to be used as reaction media for synthetic chemistry. This paper investigates the potential for the ordered structures of LCILs to influence the stereochemical outcome of the Diels-Alder reaction between cyclopentadiene and methyl acrylate. The ratio of endo- to exo-product from this reaction was monitored for a range of ionic liquids (ILs) and LCILs. Comparison of the endo:exo ratios in these reactions as a function of cation, anion and liquid crystallinity of the reaction media, allowed for the effects of liquid crystallinity to be distinguished from anion effects or cation alkyl chain length effects. These data strongly suggest that the proportion of exo-product increases as the reaction media is changed from an isotropic IL to a LCIL. A detailed molecular dynamics (MD) study suggests that this effect is related to different hydrogen bonding interactions between the reaction media and the exo- and endo-transition states in solvents with layered, smectic ordering compared to those that are isotropic. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Perforated layer structures in liquid crystalline block copolymers (United States)

    Tenneti, Kishore; Chen, Xiaofang; Li, Christopher; Tu, Yingfeng; Wan, Xinhua; Zhou, Qi-Feng; Sics, Igors; Hsiao, Benjamin


    Phase structures of a series of poly(styrene-block-(2,5-bis-(4- methoxyphenyl)oxycarbonyl)styrene) (PS-b-PMPCS) liquid crystalline “rod-coil” block copolymers (LCBCPs) were investigated using thermal analysis, X-ray analysis and transmission electron microscopy. In the low molecular weight asymmetric BCP system, perforated layer structures were observed where the excessive PS molecules punctured the PMPCS domains and these perforations uniquely possess tetragonal in- plane symmetry. In the high molecular weight system, these perforated layer structures were observed in symmetric samples. Randomly initiated perforations became more regular and uniform upon blending with PS homopolymer in symmetric BCPs. These regular perforations also possess tetragonal in-plane symmetry.

  16. Volume phase transitions of cholesteric liquid crystalline gels

    Energy Technology Data Exchange (ETDEWEB)

    Matsuyama, Akihiko, E-mail: [Department of Bioscience and Bioinformatics, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, Kawazu 680-4, Iizuka, Fukuoka 820-8502 (Japan)


    We present a mean field theory to describe anisotropic deformations of a cholesteric elastomer without solvent molecules and a cholesteric liquid crystalline gel immersed in isotropic solvents at a thermal equilibrium state. Based on the neoclassical rubber theory of nematic elastomers, we derive an elastic energy and a twist distortion energy, which are important to determine the shape of a cholesteric elastomer (or gel). We demonstrate that when the elastic energy dominates in the free energy, the cholesteric elastomer causes a spontaneous compression in the pitch axis and elongates along the director on the plane perpendicular to the pitch axis. Our theory can qualitatively describe the experimental results of a cholesteric elastomer. We also predict the first-order volume phase transitions and anisotropic deformations of a gel at the cholesteric-isotropic phase transition temperature. Depending on a chirality of a gel, we find a prolate or oblate shape of cholesteric gels.

  17. Simulations of Shearing Rheology of Thermotropic Liquid Crystalline Polymers (United States)

    Chen, Hongyan; Leonov, Arkady I.


    The simulations present a first attempt to describe the rheological properties of thermotropic liquid crystalline polymers (LCP's), using recently developed thermodynamic theory of weakly viscoelastic nematodynamics. In this mono-domain theory the complicated rheological properties of nematic LCP's are modeled by a set of quasi-linear anisotropic viscoelastic constitutive equations (CE) with anisotropy described by director. The viscoelastic evolution of stress is coupled with the evolution of director. Although this theory has been developed for small values of elastic strains, it is still possible to compare the simulations with experimental data. There are 8 parameters in the theory: 3 viscosities, 3 elastic moduli, and 2 tumbling (elastic and viscous) parameters. We demonstrate that our simulations in monodomain, aligning case are in a semi-quantitative agreement with experimental data for steady, start up shearing flows and relaxation for two industrial and two "academic" LCP's. Dependencies of fitted theoretical parameters on temperature and structure of LCP's are also discussed.

  18. Liquid crystalline solutions of cellulose in phosphoric acid for preparing cellulose yarns

    NARCIS (Netherlands)

    Boerstoel, H.


    The presen thesis describes a new process for manufacturing high tenacity and high modulus cellulose yarns. A new direct solvent for cellulose has been discovered, leading to liquid crystalline solutions. This new solvent, superphosphoric acid, rapidly dissolves cellulose. These liquid crystalline

  19. Drug Release and Skin Permeation from Lipid Liquid Crystalline Phases (United States)

    Costa-Balogh, F. O.; Sparr, E.; Sousa, J. J. S.; Pais, A. A. C. C.

    We have studied drug release and skin permeation from several different liquid crystalline lipid formulations that may be used to control the respective release rates. We have studied the release and permeation through human skin of a water-soluble and amphiphilic drug, propranolol hydrochloride, from several formulations prepared with monoolein and phytantriol as permeation enhancers and controlled release excipients. Diolein and cineol were added to selected formulations. We observed that viscosity decreases with drug load, wich is compatible with the occurrence of phase changes. Diolein stabilizes the bicontinuous cubic phases leading to an increase in viscosity and sustained release of the drug. The slowest release was found for the cubic phases with higher viscosity. Studies on skin permeation showed that these latter formulations also presented lower permeability than the less viscous monoolein lamellar phases. Formulations containing cineol originated higher permeability with higher enhancement ratios. Thus, the various formulations are adapted to different circumstances and delivery routes. While a slow release is usually desired for drug sustained delivery, the transdermal route may require a faster release. Lamellar phases, which are less viscous, are more adapted to transdermal applications. Thus, systems involving lamellar phases of monoolein and cineol are good candidates to be used as skin permeation enhancers for propranolol hydrochloride.

  20. Liquid Crystalline Networks toward Regenerative Medicine and Tissue Repair. (United States)

    Martella, Daniele; Paoli, Paolo; Pioner, Josè M; Sacconi, Leonardo; Coppini, Raffaele; Santini, Lorenzo; Lulli, Matteo; Cerbai, Elisabetta; Wiersma, Diederik S; Poggesi, Corrado; Ferrantini, Cecilia; Parmeggiani, Camilla


    The communication reports the use of liquid crystalline networks (LCNs) for engineering tissue cultures with human cells. Their ability as cell scaffolds for different cell lines is demonstrated. Preliminary assessments of the material biocompatibility are performed on human dermal fibroblasts and murine muscle cells (C2C12), demonstrating that coatings or other treatments are not needed to use the acrylate-based materials as support. Moreover, it is found that adherent C2C12 cells undergo differentiation, forming multinucleated myotubes, which show the typical elongated shape, and contain bundles of stress fibers. Once biocompatibility is demonstrated, the same LCN films are used as a substrate for culturing human induced pluripotent stem cell-derived cardiomyocites (hiPSC-CMs) proving that LCNs are capable to develop adult-like dimensions and a more mature cell function in a short period of culture in respect to standard supports. The demonstrated biocompatibility together with the extraordinary features of LCNs opens to preparation of complex cell scaffolds, both patterned and stimulated, for dynamic cell culturing. The ability of these materials to improve cell maturation and differentiation will be developed toward engineered heart and skeletal muscular tissues exploring regenerative medicine toward bioartificial muscles for injured sites replacement. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Dynamical Study of Guest-Host Orientational Interaction in LiquidCrystalline Materials

    Energy Technology Data Exchange (ETDEWEB)

    Truong, Thai Viet [Univ. of California, Berkeley, CA (United States)


    Guest-host interaction has long been a subject of interest in many disciplines. Emphasis is often on how a small amount of guest substance could significantly affect the properties of a host material. This thesis describe our work in studying a guest-host effect where dye-doping of liquid crystalline materials greatly enhances the optical Kerr nonlinearity of the material. The dye molecules, upon excitation and via intermolecular interaction, provides an extra torque to reorient the host molecules, leading to the enhanced optical Kerr nonlinearity. We carried out a comprehensive study on the dynamics of the photoexcited dye-doped liquid crystalline medium. Using various experimental techniques, we separately characterized the dynamical responses of the relevant molecular species present in the medium following photo-excitation, and thus were able to follow the transient process in which photo-excitation of the dye molecules exert through guest-host interaction a net torque on the host LC material, leading to the observed enhanced molecular reorientation. We also observed for the first time the enhanced reorientation in a pure liquid crystal system, where the guest population is created through photoexcitation of the host molecules themselves. Experimental results agree quantitatively with the time-dependent theory based on a mean-field model of the guest-host interaction.

  2. The effect of a cholesterol liquid crystalline structure on osteoblast cell behavior

    Energy Technology Data Exchange (ETDEWEB)

    Xu Jianping; Ji Jian; Shen Jiacong, E-mail: [Department of Polymer Science, Key Laboratory of Macromolecule Synthesis and Functionalization of Minster of Education, Zhejiang University, Hangzhou, 310027 (China)


    To investigate the effect of a liquid crystalline structure on cell behavior, polymethylsiloxane-graft-(10-cholesteryloxydecanol) was specially designed to get a thermotropic liquid crystalline polymer. Results of Fourier transform infrared (FT-IR) spectroscopy, proton nuclear magnetic resonance ({sup 1}H-NMR) spectroscopy and gel permeation chromatography (GPC) indicated that cholesterol was successfully covalently grafted onto polymethylhydrosiloxane via decamethylene 'flexible spacer'. Differential scanning calorimetry (DSC) and polarized optical microscopy (POM) investigations revealed that the copolymer with 44.9% mesogenic unit showed obvious thermotropic liquid crystalline transition at about 124.9 deg. C. Polymer films were prepared by spin coating on clean glass plates from 5 mg ml{sup -1} toluene solutions of the copolymers. The POM investigation indicated that while the unannealed films (SC15, SC45) showed no liquid crystalline structure, the films which were annealed in vacuo at 140 deg. C for 9 h and then quenched to room temperature (SC15C, SC45C) formed discrete island-like liquid crystalline and continuous liquid crystalline structures, respectively. Osteoblast cells (MC3T3) were chosen to test the cell behavior of annealed and unannealed films. In comparison to unannealed films, the annealed films with a cholesterol liquid crystalline structure could promote osteoblast cell attachment and growth significantly.

  3. Physics of liquid and crystalline plasmas: Future perspectives (United States)

    Morfill, G. E.

    It has been shown that under certain conditions "complex plasmas" (plasma containing ions, electrons and charged microspheres) may undergo spontaneous phase changes to become liquid and crystalline, without recombination of the charge components. Hence these systems may be regarded as new plasma states "condensed plasmas". The ordering forces are mainly electrostatic, but dipolar effects, anisotropic pressure due shielding, ion flow focussing etc. may all play a role, too. Complex plasmas are of great interest from a fundamental research point of view because the individual particles of one plasma component (the charged microspheres) can be visualised and hence the plasma can be studied at the kinetic level. Also, the relevant time scales (e.g. 1/plasma frequency) are of order 0.1 sec, the plasma processes occur practically in "slow motion". We will discuss some physical processes (e.g. wave propagation, shocks, phase transitions) of these systems and outline the potential of the research for the understanding of strongly coupled systems. Technologically, it is expected that colloidal plasmas will also become very important, because both plasma technology and colloid technology are widely developed already. In this overview first the basic forces between the particles are discussed, then the phase transitions, the lattice structures and results from active experiments will be presented. Finally the future perspectives will be discussed, from the scientific potential point of view and the experimental approaches in the laboratory and in space. Experiments under microgravity conditions are of great importance, because the microspheres are 10's of billions times heavier than the ions.

  4. Functionalized Nanoporous Polymer Membranes with Well-Defined Pore Architectures via Lyotropic Liquid-Crystalline Monomers

    National Research Council Canada - National Science Library

    Gin, Douglas


    .... Two lyotropic liquid-crystalline monomer platforms have been synthesized. The interchannel separations in the polymerizable materials can be varied in the 30-40 A range by the choice of counterion on the ionic headgroup of the monomers...

  5. Selection of thermotropic liquid crystalline polymers for rotational molding (United States)

    Scribben, Eric

    Thermotropic liquid crystalline polymers (TLCPs) possess a number of physical and mechanical properties such as: excellent chemical resistance, low permeability, low coefficient of thermal expansion, high tensile strength and modulus, and good impact resistance, which make them desirable for use in the storage of cryogenic fluids. Rotational molding was selected as the processing method for these containers because it is convenient for manufacturing large storage vessels from thermoplastics. Unfortunately, there are no reports of successful TLCP rotational molding in the technical literature. The only related work reported involved the static coalescence of two TLCP powders, where three key results were reported that were expected to present problems that preclude the rotational molding process. The first result was that conventional grinding methods produced powders that were composed of high aspect ratio particles. Secondly, coalescence was observed to be either slow or incomplete and speculated that the observed difficulties with coalescence may be due to large values of the shear viscosity at low deformation rates. Finally, complete densification was not observed for the high aspect ratio particles. However, the nature of these problems were not evaluated to determine if they did, in fact, create processing difficulties for rotational molding or if it was possible to develop solutions to the problems to achieve successful rotational molding. This work is concerned with developing a resin selection method to identify viable TLCP candidates and establish processing conditions for successful rotational molding. This was accomplished by individually investigating each of the phenomenological steps of rotational molding to determine the requirements for acceptable performance in, or successful completion of, each step. The fundamental steps were: the characteristics and behavior of the powder in solids flow, the coalescence behavior of isolated particles, and the

  6. Formation of a liquid-crystalline interpenetrating poly-(ionic liquid) network hydrogel.

    Energy Technology Data Exchange (ETDEWEB)

    Becht, G. A.; Sofos, M.; Seifert, S.; Firestone, M. A. (Materials Science Division); ( XSD)


    Preparation of a liquid-crystalline ionic-liquid (IL)-based interpenetrating polymer network (IPN) is described. The IPN is prepared sequentially by first photopolymerizing a self-assembled aqueous mixture of an IL monomer (1-(10-(acryloyloxy)decyl)-3-methylimidazolium chloride) that possesses an acryloyl moiety at the terminus of a C{sub 10} alkyl chain of the IL cation. In the second step, an acrylate counteranion is introduced and then photopolymerized to yield a durable self-supporting network polymer. Thermal analysis indicates the formation of a homogeneous (well-blended constituent polymers) IPN. The IPN adopts a lamellar structure possessing some residual in-plane tetragonal perforations, as evidenced by small-angle X-ray scattering (SAXS). The IPN can absorb large quantities of water, swelling to nearly 60 times its original volume, but retains mechanical integrity making it a durable hydrogel.

  7. Effect of cellulose crystallinity on the formation of a liquid intermediate and on product distribution during pyrolysis

    NARCIS (Netherlands)

    Wang, Zhouhong; McDonald, Armando G.; Westerhof, Roel Johannes Maria; Kersten, Sascha R.A.; Cuba-Torres, Christian M.; Ha, Su; Pecha, Brennan; Garcia-Perez, Manuel


    The effect of cellulose crystallinity on the formation of a liquid intermediate and on its thermal degradation was studied thermogravimetrically and by Py-GC/MS using a control cellulose (Avicel, crystallinity at 60.5%) and ball-milled Avicel (low cellulose crystallinity at 6.5%). The crystallinity

  8. Liquid Crystalline Thermosets from Ester, Ester-imide, and Ester-amide Oligomers (United States)

    Dingemans, Theodorus J. (Inventor); Weiser, Erik S. (Inventor); St. Clair, Terry L. (Inventor)


    Main chain thermotropic liquid crystal esters, ester-imides, and ester-amides were prepared from AA, BB, and AB type monomeric materials and end-capped with phenylacetylene, phenylmaleimide, or nadimide reactive end-groups. The end-capped liquid crystal oligomers are thermotropic and have, preferably, molecular weights in the range of approximately 1000-15,000 grams per mole. The end-capped liquid crystaloligomers have broad liquid crystalline melting ranges and exhibit high melt stability and very low melt viscosities at accessible temperatures. The end-capped liquid crystal oli-gomers are stable forup to an hour in the melt phase. They are highly processable by a variety of melt process shape forming and blending techniques. Once processed and shaped, the end-capped liquid crystal oigomers were heated to further polymerize and form liquid crystalline thermosets (LCT). The fully cured products are rubbers above their glass transition temperatures.

  9. Cross-Linked Liquid Crystalline Systems From Rigid Polymer Networks to Elastomers

    CERN Document Server

    Broer, Dirk


    With rapidly expanding interest in liquid crystalline polymers and elastomers among the liquid crystal community, researchers are currently exploring the wide range of possible application areas for these unique materials, including optical elements on displays, tunable lasers, strain gauges, micro-structures, and artificial muscles. Written by respected scientists from academia and industry around the world, who are not only active in the field but also well-known in more traditional areas of research, "Cross-Linked Liquid Crystalline Systems: From Rigid Polymer Networks to Elastomers&qu

  10. Pattern of liquid crystalline droplets induced by two beam interference in azobenzene derivative (United States)

    Czajkowski, Maciej; Dradrach, Klaudia; Bartkiewicz, Stanislaw; Galewski, Zbigniew


    A pattern of liquid crystalline droplets dispersed in the isotropic liquid can be formed during illumination by two interfering laser beams in certain range of the temperature and the light intensity. Azobenzene derivative substituted by long alkyl and alkoxy chains exhibiting smectic phases has been used for the study. The pattern can be reversibly erased and rewritten by shutting down and opening of the interfering beams. Polarized microscope images have shown the formation of numerous liquid crystalline droplets at bright regions of the interference fringes. Influence of the temperature and the light intensity has been studied by measuring the diffraction efficiency dynamics. Photothermal and photoorientational mechanisms of the formation of liquid crystalline droplets pattern have been proposed and discussed.

  11. Orientation of liquid crystalline materials by using carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Kamanina N.V.


    Full Text Available The solution of some problems, where the initial black field is necessary for the regime of light transmission through the electrooptical organic nematic liquid crystal structures has been considered via a homeotropic alignment of liquid crystal molecules on the substrate covered by carbon nanotubes. The results of this investigation can be used to develop optical elements for displays with vertical orientations of nematic liquid crystal molecules (for example, for MVA-display technology.

  12. Liquid Crystalline Epoxies with Lateral Substituents Showing a Low Dielectric Constant and High Thermal Conductivity (United States)

    Guo, Huilong; Lu, Mangeng; Liang, Liyan; Wu, Kun; Ma, Dong; Xue, Wei


    In this work, liquid crystalline epoxies with lateral substituents were synthesized and cured with aromatic amines or anhydride. The liquid crystalline phase structure of liquid crystalline epoxies with lateral substituents was determined by polarized optical microscopy. The relationship between thermal conductivity and dielectric properties and liquid crystalline domain structure was discussed in the paper. The samples show high thermal conductivity up to 0.29 W/(m × K), due to the orientation of mesogenic units in epoxies. The sample's low dielectric constant of 2.29 is associated with the oriented mesogenic units and long nonpolar lateral substituents. This indicates a new way to obtain materials with high thermal conductivity and a low dielectric constant by introducing oriented mesogenic units into cross-linked epoxy systems. The water repellency is reflected in the contact angles of 92-98°, which are apparently higher than that of conventional epoxy systems. It was also found that the better toughness of liquid crystalline epoxies with lateral substituents was attributed to the existence of long flexible alkyl lateral substituents.

  13. Spatial ordering and abnormal optical activity of DNA liquid-crystalline dispersion particles

    Directory of Open Access Journals (Sweden)

    Semenov S.V.


    Full Text Available In our work, we investigate physicochemical and optical properties of double-strand DNA dispersions. The study of these properties is of biological interest, because it allows one to describe the characteristics of certain classes of chromosomes and DNA containing viruses. The package pattern of DNA molecules in the dispersions particles (DP is examined. The consideration of the DNA liquid-crystalline DP optical activity based on the theory of electromagnetic wave absorption by large molecular aggregates has been performed. The investigation is also focused on various effects induced by the interaction between biological active compounds and DNA in the content of liquid-crystalline DP.

  14. Thermomagnetic processing of liquid-crystalline epoxy resins and their mechanical characterization using nanoindentation. (United States)

    Li, Yuzhan; Rios, Orlando; Kessler, Michael R


    A thermomagnetic processing method was used to produce a biphenyl-based liquid-crystalline epoxy resin (LCER) with oriented liquid-crystalline (LC) domains. The orientation of the LCER was confirmed and quantified using two-dimensional X-ray diffraction. The effect of molecular alignment on the mechanical and thermomechanical properties of the LCER was investigated using nanoindentation and thermomechanical analysis, respectively. The effect of the orientation on the fracture behavior was also examined. The results showed that macroscopic orientation of the LC domains was achieved, resulting in an epoxy network with an anisotropic modulus, hardness, creep behavior, and thermal expansion.

  15. SRG Inscription in Supramolecular Liquid Crystalline Polymer Film: Replacement of Mesogens

    Directory of Open Access Journals (Sweden)

    Shun Mitsui


    Full Text Available The photoinduced surface relief formation via mass transfer upon irradiation with patterned light has long been a subject of extensive investigation. In azobenzene-containing liquid crystalline materials, UV light irradiation that generates the cis isomer leads to the liquid crystal to isotropic photochemical transition. Due to this phase change, efficiency of the mass transfer to generate a surface relief grating (SRG becomes markedly greater. We have previously indicated that azobenzene-colored SRG-inscribed film can be bleached by removing a hydrogen-bonded azobenzene mesogen. However, this process largely reduces the height feature of the SRG corrugation. Herein, we propose an extended procedure where a colorless mesogen is filled successively after the removal of the azobenzene side chain. The process involves four stages: (i SRG inscription in a hydrogen-bonded supramolecular azobenzene material; (ii crosslinking (insolubilization of the SRG film; (iii removal of azobenzene mesogen by rinsing with a solvent, and (iv stuffing the hollow film with a different mesogen. Although the final stuffing stage was insufficient at the present stage, this work demonstrates the possibility and validity of the strategy of mesogen replacement.

  16. Planar-fingerprint transition in a thermoreversible liquid crystalline gel (United States)

    de Lózar, Alberto; Schöpf, Wolfgang; Rehberg, Ingo; Lafuente, Oscar; Lattermann, Günter


    A thermoreversible (physical) gel consisting of a nematic liquid crystal mixed with a small quantity of a chiral organogelator is investigated in the planar configuration. The response of the system to an external electric field reveals multistability within a small hysteresis. The relaxation of the liquid crystal under this field is characterized by two different time scales: a fast one that is connected to the tilt of the director field, and a slow one that describes the reorientation of the chiral structure. In the first case, the relaxation is nonexponential and can be described by a Kohlrausch-Williams-Watts law with a stretching parameter of 0.5.

  17. On some liquid crystalline phases exhibited by compounds made of ...

    Indian Academy of Sciences (India)

    Using polarized infrared spectroscopy we find that the mutual orientation of the R and BC molecules in the SmA db liquid crystal is such that the arrow axes of the BC molecules are along the layer normal of the partial bi- layer smectic structure formed by the rods. We also describe unusual growth patterns obtained when.

  18. Synthesis and Characterization of Liquid Crystalline Epoxy Resins (United States)


    Science and Technology Section A-Molecular Crystals and Liquid Crystals 1995;266:9-22. [22] Mallon JJ and Adams PM. Journal of Polymer Science Part...EJ. Macromolecules 1998;31(13):4074-4088. [5] Mallon JJ and Adams PM. Journal of Polymer Science Part A-Polymer Chemistry 1993;31(9):2249-2260

  19. Synthesis and Supramolecular Chemistry of Novel Liquid Crystalline Crown Ether-Substituted Phthalocyanines : Toward Molecular Wires and Molecular Ionoelectronics

    NARCIS (Netherlands)

    Nostrum, Cornelus F. van; Picken, Stephen J.; Schouten, Arend-Jan; Nolte, Roeland J.M.


    The synthesis of the metal-free and the dihydroxysilicon derivatives of tetrakis[4’,5’-bis(decoxy)benzo-18-crown-6]phthalocyanine is described. The metal-free phthalocyanine is liquid crystalline and exhibits a crystalline phase to mesophase transition at 148 °C. The structures of the crystalline

  20. Double-twist cylinders in liquid crystalline cholesteric blue phases observed by transmission electron microscopy


    Shu Tanaka; Hiroyuki Yoshida; Yuto Kawata; Ryusuke Kuwahara; Ryuji Nishi; Masanori Ozaki


    Cholesteric blue phases are liquid crystalline phases in which the constituent rod-like molecules spontaneously form three-dimensional, helical structures. Despite theoretical predictions that they are composed of cylindrical substructures within which the liquid crystal molecules are doubly twisted, real space observation of the arrangement of such structures had not been performed. Through transmission electron microscopy of photopolymerized blue phases with controlled lattice plane orienta...

  1. On some liquid crystalline phases exhibited by compounds made of ...

    Indian Academy of Sciences (India)


    Nov 27, 2015 ... This system exhibits the biaxial smectic A phase down to 30°C. Using polarized infrared spectroscopy we find that the mutual orientation of the R and BC molecules in the SmAdb liquid crystal is such that the arrow axes of the BC molecules are along the layer normal of the partial bilayer smectic structure ...

  2. The influence of lung surfactant liquid crystalline nanostructures on respiratory drug delivery. (United States)

    Das, Shyamal C; Stewart, Peter J


    The respiratory route increasingly has been used for both local and systemic drug delivery. Although drug is absorbed rapidly after respiratory delivery, the role of lung surfactant in drug delivery is not well understood. The human lung contains only around 15mL of surface lining fluid spread over ∼100m2 surface. The fluid contains lung surfactant at a concentration of 8-24mg/kg/body weight; the lung surfactant which is lipo-protein in nature can form different liquid crystalline nanostructures. After a brief overview of the anatomy of respiratory system, the review has focused on the current understanding of lung surface lining fluid, lung surfactants and their composition and possible self-assembled nanostructures. The role of lung surfactant in drug delivery and drug dissolution has been briefly considered. Lung surfactant may form different liquid crystalline phases which can have an active role in drug delivery. The hypotheses developed in this review focuses on the potential roles of surface epithelial fluid containing liquid crystalline nanostructures in defining the dissolution mechanism and rate. The hypotheses also focus an understanding how liquid crystalline nanostructures can be used to control dissolution rate and how the nanostructures might be changed to influence delivery and induce toxicity. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Novel biphotonic holographic storage in a side-chain liquid crystalline polyester

    DEFF Research Database (Denmark)

    Ramanujam, P.S.; Hvilsted, S.; Andruzzi, F.


    We report novel biphotonic holographic storage of text and gratings on unoriented films of a side-chain liquid crystalline polyester capable of high density storage and complete erasure. The holograms have a typical size of 1 mm. The recording utilizes unusual photochemistry involving azo dye...

  4. On the morphology of a discotic liquid crystalline charge transfer complex. (United States)

    Haverkate, Lucas A; Zbiri, Mohamed; Johnson, Mark R; Deme, Bruno; de Groot, Huub J M; Lefeber, Fons; Kotlewski, Arkadiusz; Picken, Stephen J; Mulder, Fokko M; Kearley, Gordon J


    Discotic liquid crystalline (DLC) charge transfer (CT) complexes, which combine visible light absorption with rapid charge transfer characteristics within the CT complex, can have a great potential for photovoltaic applications when they can be made to self-assemble in a bulk heterojunction arrangement with separate channels for electron and hole conduction. However, the morphology of some liquid crystalline CT complexes has been under debate for many years. In particular, the liquid crystalline CT complex built from the electron acceptor 2,4,7-trinitro-9-fluorenone (TNF) and discotic molecules has been reported to have the TNF "sandwiched" either between the discotic molecules within the same column or between the columns within the aliphatic tails of the discotic molecules. We present a detailed structural study of the prototypic 1:1 mixture of the discotic 2,3,6,7,10,11-hexakis(hexyloxy)triphenylene (HAT6) and TNF. Nuclear magnetic resonance (NMR) line widths and cross-polarization rates are consistent with the picosecond time scale anisotropic thermal motions of the HAT6 and TNF molecules previously observed. By computational integration of Rietveld refinement analyses of neutron diffraction patterns with density experiments and short-range structural constraints from heteronuclear 2D NMR, we determine that the TNF molecules are vertically oriented between HAT6 columns. The data provide the insight that a morphology of separate hole conducting channels of HAT6 molecules can be realized in the liquid crystalline CT complex.

  5. Light-induced circular birefringence in cyanoazobenzene side-chain liquid-crystalline polyester films

    DEFF Research Database (Denmark)

    Naydenova, I; Nikolova, L; Ramanujam, P.S.


    We report the inducement of large circular birefringence (optical activity) in films of a cyanoazobenzene side-chain liquid-crystalline polyester on illumination with circularly polarized light. The polyester has no chiral groups and is initially isotropic. The induced optical rotation is up to 5...

  6. Droplet snap-off in fluids with nematic liquid crystalline ordering

    NARCIS (Netherlands)

    Verhoeff, A.A.|info:eu-repo/dai/nl/304829579; Lekkerkerker, H.N.W.|info:eu-repo/dai/nl/159054885


    We studied the snap-off of nematic liquid crystalline droplets originating from the Rayleigh–Taylor instability at the isotropic–nematic interface in suspensions of charged gibbsite in water and sterically stabilized gibbsite in bromotoluene. We found that droplet snap-off strongly depends on the

  7. A paint removal concept with side-chain liquid crystalline polymers as primer material

    NARCIS (Netherlands)

    Wielen, van der M.W.J.; Cohen Stuart, M.A.; Fleer, G.J.; Nieuwhof, R.P.; Marcelis, A.T.M.; Sudhölter, E.J.R.


    A new paint removal concept is introduced making use of a polymer primer layer with a sharp softening temperature. For this, a new class of side-chain liquid crystalline polymers with polar moieties in the backbone has been developed and studied in thin films. These polymers form lamellar-ordered

  8. Diethynylbenzene-based liquid crystalline semiconductor for solution-processable organic thin-film transistors. (United States)

    Madathil, Pramod Kandoth; Heinrich, Benoît; Donnio, Bertrand; Mathevet, Fabrice; Fave, Jean-Louis; Guillon, Daniel; Attias, Andre-Jean; Lee, Changjin; Kim, Tae-Dong; Lee, Kwang-Sup


    We report here the synthesis and characterization of novel diethynylbenzene-based liquid crystalline semiconductor (P1) for organic thin-film transistors (OTFTs). Compound P1 was synthesized by the Sonogashira coupling reaction between 2-bromo-5-(4-hexylthiophen-2-yl)thieno[3,2-b]thiophene and 1,4-bis(dodecyloxy)-2,5-diethynylbenzene. Top contact OTFTs were fabricated by spin casting with 2 wt% solution of P1 in chloroform and their best performance, which exhibited a hole mobility of 4.5 x 10(-5) cm2/Vs, was showed after annealing of the films at liquid crystalline temperature. Time-of-flight (TOF) mobility measured at liquid crystalline phase was observed to be 1.5 x 10(-6) cm2/Vs for both positive and negative carriers. These results indicate that the liquid crystallinity helps to improve the molecular packing and enhance charge mobility for P1. These advantages can be applicable to design and construct solution-processable OTFT materials for electronic applications.

  9. Side-chain liquid-crystalline polyesters for optical information storage

    DEFF Research Database (Denmark)

    Hvilsted, Søren; Andruzzi, F.; Ramanujam, P.S.


    We report erasable holographic recording with a resolution of at least 2500 lines/mm on unoriented films of side-chain liquid-crystalline polyesters. Recording energies of approximately 1 J/cm2 have been used. We have obtained a diffraction efficiency of approximately 30% with polarization...

  10. Control of structure and growth of polymorphic crystalline thin films of amphiphilic molecules on liquid surfaces

    DEFF Research Database (Denmark)

    Weinbach, S.P.; Kjær, K.; Bouwman, W.G.


    The spontaneous formation and coexistence of crystalline polymorphic trilayer domains in amphiphilic films at air-liquid interfaces is demonstrated by grazing incidence synchrotron x-ray diffraction. These polymorphic crystallites may serve as models for the early stages of crystal nucleation...

  11. Orientation of liquid-crystalline suspensions of vanadium pentoxide ribbons by a magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Commeinhes, X.; Davidson, P. [Universite de Paris-Sud, Orsay (France). Lab. de Phys. des Solides; Bourgaux, C.; Livage, J.


    Non-invasive alignment and rotation of liquid-crystalline suspensions of vanadium pentoxide ribbons by a magnetic field is reported. The ribbons align if the magnetic field, initially applied along the capillary main axis, is perpendicular to the main axis. It is believed that this simple idea could be applied to any nematic suspension of mineral compounds. (orig.) 27 refs.

  12. Detection of graphene chirality using achiral liquid crystalline platforms (United States)

    Basu, Rajratan; Kinnamon, Daniel; Garvey, Alfred


    Monolayer graphene flakes were dispersed at low concentrations into two achiral liquid crystals (LCs) alkoxyphenylbenzoate (9OO4) and 4-cyano-4'-pentylbiphenyl (5CB), separately. The presence of graphene resulted in two types of chiral signatures in the LCs: an electroclinic effect (a polar tilt of the LC director perpendicular to, and linear in, an applied electric field) in the smectic-A phase of 9OO4, and a macroscopic helical twist of the LC director in the nematic phase of 5CB. Graphene flakes generally possess strain chirality and edge chirality. The non-covalent interactions between the LC molecules and chiral graphene flakes induce molecular conformational deracemization in the LC, exhibiting a bulk electroclinic effect and a macroscopic helical twist.

  13. Phase behaviour of macromolecular liquid crystalline materials. Computational studies at the molecular level

    CERN Document Server

    Stimson, L M


    Molecular simulations provide an increasingly useful insight into the static and dynamic characteristics of materials. In this thesis molecular simulations of macro-molecular liquid crystalline materials are reported. The first liquid crystalline material that has been investigated is a side chain liquid crystal polymer (SCLCP). In this study semi-atomistic molecular dynamics simulations have been conducted at a range of temperatures and an aligning potential has been applied to mimic the effect of a magnetic field. In cooling the SCLCP from an isotropic melt, microphase separation was observed yielding a domain structure. The application of a magnetic field to this structure aligns the domains producing a stable smectic mesophase. This is the first study in which mesophases have been observed using an off-lattice model of a SCLCP. The second material that has been investigated is a dendrimer with terminal mesogenic functionalization. Here, a multi-scale approach has been taken with Monte Carlo studies of a s...

  14. Biphenyl liquid crystalline epoxy resin as a low-shrinkage resin-based dental restorative nanocomposite. (United States)

    Hsu, Sheng-Hao; Chen, Rung-Shu; Chang, Yuan-Ling; Chen, Min-Huey; Cheng, Kuo-Chung; Su, Wei-Fang


    Low-shrinkage resin-based photocurable liquid crystalline epoxy nanocomposite has been investigated with regard to its application as a dental restoration material. The nanocomposite consists of an organic matrix and an inorganic reinforcing filler. The organic matrix is made of liquid crystalline biphenyl epoxy resin (BP), an epoxy resin consisting of cyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (ECH), the photoinitiator 4-octylphenyl phenyliodonium hexafluoroantimonate and the photosensitizer champhorquinone. The inorganic filler is silica nanoparticles (∼70-100 nm). The nanoparticles were modified by an epoxy silane of γ-glycidoxypropyltrimethoxysilane to be compatible with the organic matrix and to chemically bond with the organic matrix after photo curing. By incorporating the BP liquid crystalline (LC) epoxy resin into conventional ECH epoxy resin, the nanocomposite has improved hardness, flexural modulus, water absorption and coefficient of thermal expansion. Although the incorporation of silica filler may dilute the reinforcing effect of crystalline BP, a high silica filler content (∼42 vol.%) was found to increase the physical and chemical properties of the nanocomposite due to the formation of unique microstructures. The microstructure of nanoparticle embedded layers was observed in the nanocomposite using scanning and transmission electron microscopy. This unique microstructure indicates that the crystalline BP and nanoparticles support each other and result in outstanding mechanical properties. The crystalline BP in the LC epoxy resin-based nanocomposite was partially melted during exothermic photopolymerization, and the resin expanded via an order-to-disorder transition. Thus, the post-gelation shrinkage of the LC epoxy resin-based nanocomposite is greatly reduced, ∼50.6% less than in commercialized methacrylate resin-based composites. This LC epoxy nanocomposite demonstrates good physical and chemical properties and good biocompatibility

  15. Dancing with light advances in photofunctional liquid-crystalline materials

    CERN Document Server

    Yu, Haifeng


    Recent progress in this field indicates that integrating photochromic molecules into LC materials enables one to photo-manipulate unique features such as photoinduced phase transition, photocontrolled alignment and phototriggered molecular cooperative motion, leading to their novel applications beyond displays. This book introduces readers to this field, from the primary- to the advanced level in photoresponsive LC materials. The subject is introduced step-by-step, including the basic knowledge of LCs, photoresponsive properties of LCs, and their detailed performances in the form of low-molecu

  16. Fluorescence and lasing in liquid crystalline photonic bandgap materials (United States)

    Cao, Wenyi

    Cholesteric liquid crystals (CLCs) and cholesteric blue phases (BPs) are one-dimensional and three-dimensional photonic bandgap (PGB) materials. In this work, fluorescence and lasing are experimentally studied in dye-doped CLC films and BPs, together with the calculations of density of states rho in CLC films. The normal modes of light propagation in a CLC film in the direction along the helical axis have been obtained analytically, using transfer matrix method. Two normal modes are elliptically polarized and their rho differ greatly. The value and wavelength of the largest rho depend on the CLC film thickness. The fluorescence spectra of dye DCM in CLC films are greatly altered: suppressed in the stop band and enhanced at band edges with intensity oscillations. The altered fluorescence spectra are in good agreement with the calculated spectra from rho. The fluorescence lifetimes, however, have no measurable difference. At high dye concentration, the fluorescence intensity is quenched by the formation of dye excimers. Mirrorless lasing in CLC films has been studied systematically. The lasing wavelengths and thresholds are in good agreement with the calculated values from rho. The threshold is optimized over CLC film thickness and dye concentration. Lasing at defect modes has been observed in CLC composite structures. Photon-counting statistics confirms the transition from the incoherent fluorescence to coherent laser emission with increasing pump energy. The totally coherent emitting area is estimated from the diffraction pattern of the CLC laser emission. The structures of BPs are characterized through textures and reflection measurements. In BP I, the stimulated emission is due to the multiple reflection of the fluorescence by small BP I crystals. In large BP II single crystals, the fluorescence is altered and lasing occurs at edges of the reflection peak or at defect modes. Lasing in three dimensions has been observed for the first time in PGB materials, and

  17. Cholesteric Liquid Crystalline Copolymers for Gas Chromatographic Separation of Polycyclic Aromatic Compounds

    Directory of Open Access Journals (Sweden)

    Chih-Hung Lin


    Full Text Available A novel series of side-chain liquid crystalline copolysiloxanes containing [S]-1-(2-naphthyl ethyl 6-[4-(10-undecen-1-yloxy biphenyl--carbonyloxy]-2-naphthoate mesogenic and 4-biphenyl -allyloxybenzoate mesogenic side groups in the backbone and side chains liquid crystalline copolymers were prepared and evaluated as possible stationary phases for gas chromatography capillary columns. All copolymers display enantiotropic cholesteric phases. These mesomorphic polysiloxanes specimens with the widest temperature range were used as the stationary phase in a gas chromatography capillary column, and it showed good thermal and physical stability, excellent chemical inertness, and unique separation properties for polycyclic aromatic compounds. These cholesteric LC copolysiloxane stationary phases show much better separation effect for the polycyclic aromatic compound than those of the nematic and smectic LC copolysiloxanes.

  18. Liquid crystalline polymer nanocomposites reinforced with in-situ reduced graphene oxide

    Directory of Open Access Journals (Sweden)

    D. Pedrazzoli


    Full Text Available In this work liquid-crystalline polymer (LCP nanocomposites reinforced with in-situ reduced graphene oxide are investigated. Graphene oxide (GO was first synthesized by the Hummers method, and the kinetics of its thermal reduction was assessed. GO layers were then homogeneously dispersed in a thermotropic liquid crystalline polymer matrix (Vectran®, and an in-situ thermal reduction of GO into reduced graphene oxide (rGO was performed. Even at low rGO amount, the resulting nanocomposites exhibited an enhancement of both the mechanical properties and the thermal stability. Improvements of the creep stability and of the thermo-mechanical behavior were also observed upon nanofiller incorporation. Furthermore, in-situ thermal reduction of the insulating GO into the more electrically conductive rGO led to an important surface resistivity decrease in the nanofilled samples.

  19. Synthesis and Liquid Crystalline Properties of New Diols Containing Azomethine Groups

    Directory of Open Access Journals (Sweden)

    Issam Ahmed Mohammed


    Full Text Available A series of new mesogenic azomethine diols were successfully synthesized by condensation reactions between various chloroalkanols and N,N'-bis(4-hydroxy-benzylidene-o-toluidine (1. The structures of these compounds were confirmed by CHN, FT-IR, 1H-NMR, and 13C-NMR spectrophotometer. Their thermotropic liquid crystalline behavior was studied using differential scanning calorimetry (DSC and polarizing optical microscope (POM. 4,4'-di(4-Hydroxybutoxy-N-benzylidine-o-tolidine (2a does not exhibit liquid crystalline properties. A nematic texture was observed for mesogenic diols 2b, and 2d, whereas the diol 2c exhibits a smectic mesophase. The increase of terminal alkyl chain in these mesogenic diols leads to a decrease in the transition temperature.

  20. Investigations on the liquid crystalline phases of cation-induced condensed DNA (United States)

    Pillai, C. K. S.; Sundaresan, Neethu; Radhakrishnan Pillai, M.; Thomas, T.; Thomas, T. J.


    Viral and nonviral condensing agents are used in gene therapy to compact oligonucleotides and plasmid DNA into nanostructures for their efficient transport through the cell membranes. Whereas viral vectors are best by the toxic effects on the immune system, most of the nonviral delivery vehicles are not effective for use in clinical system. Recent investigations indicate that the supramolecular organization of DNA in the condensed state is liquid crystalline. The present level of understanding of the liquid crystalline phase of DNA is inadequate and a thorough investigation is required to understand the nature, stability, texture and the influence of various environmental conditions on the structure of the phase. The present study is mainly concerned with the physico-chemical investigations on the liquid crystalline transitions during compaction of DNA by cationic species such as polyamines and metallic cations. As a preliminary to the above investigation, studies were conducted on the evolution of mesophase transitions of DNA with various cationic counterion species using polarized light microscopy. These studies indicated significant variations in the phase behaviour of DNA in the presence of Li and other ions. Apart from the neutralization of the charges on the DNA molecule, these ions are found to influence selectively the hydration sphere of DNA that in turn influences the induction and stabilization of the LC phases. The higher stability observed with the liquid crystalline phases of Li--DNA system could be useful in the production of nanostructured DNA. In the case of the polyamine, a structural specificity effect depending on the nature, charge and structure of the polyamine used has been found to be favoured in the crystallization of DNA.

  1. Electrophoretic Deposition for Cholesteric Liquid-Crystalline Devices with Memory and Modulation of Reflection Colors. (United States)

    Tokunaga, Shoichi; Itoh, Yoshimitsu; Yaguchi, Yuya; Tanaka, Hiroyuki; Araoka, Fumito; Takezoe, Hideo; Aida, Takuzo


    The first design strategy that allows both memorization and modulation of the liquid-crystalline reflection color is reported. Electrophoretic deposition of a tailored ionic chiral dopant is key to realizing this unprecedented function, which may pave the way for the development of full-color e-paper that can operate without the need of color filters. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. The use of exchangeable nuclei to observe enantiomers through deuterium NMR in chiral liquid crystalline solvents. (United States)

    Palomino, Martina; Khudr, Hussein; Courtieu, Jacques; Merlet, Denis; Meddour, Abdelkrim


    It is demonstrated that (2)H NMR in chiral liquid crystalline solvents can be used to measure enantiomeric excesses using exchangeable deuterons in alcohols. This is performed in a trivial way at low temperature (260-270 K) where a slow exchange regime was reached. Among the various alcohols used to explore the possibilities of this technique, an unusually large isotopic effect on molecular orientation between two isotopomers has been observed. Copyright © 2012 John Wiley & Sons, Ltd.

  3. A simple model of liquid-crystalline magnetic suspension of anisometric particles

    Energy Technology Data Exchange (ETDEWEB)

    Zakhlevnykh, A.N., E-mail:; Lubnin, M.S.; Petrov, D.A.


    On the base of molecular-statistical approach we study the phase transition between the ordered (ferromagnetic) and disordered (paramagnetic) phases in liquid-crystalline suspensions of magnetic nanoparticles in an external magnetic field. The free energy and equations of magnetic and orientational equilibrium are obtained in the framework of spherical approximation. - Highlights: • We propose a simple statistical model of ferronematic liquid crystals. • We use spherical approximation to derive equations of state. • We study magnetic field induced order-disorder transitions.

  4. From Cellulosic Based Liquid Crystalline Sheared Solutions to 1D and 2D Soft Materials

    Directory of Open Access Journals (Sweden)

    Maria Helena Godinho


    Full Text Available Liquid crystalline cellulosic-based solutions described by distinctive properties are at the origin of different kinds of multifunctional materials with unique characteristics. These solutions can form chiral nematic phases at rest, with tuneable photonic behavior, and exhibit a complex behavior associated with the onset of a network of director field defects under shear. Techniques, such as Nuclear Magnetic Resonance (NMR, Rheology coupled with NMR (Rheo-NMR, rheology, optical methods, Magnetic Resonance Imaging (MRI, Wide Angle X-rays Scattering (WAXS, were extensively used to enlighten the liquid crystalline characteristics of these cellulosic solutions. Cellulosic films produced by shear casting and fibers by electrospinning, from these liquid crystalline solutions, have regained wider attention due to recognition of their innovative properties associated to their biocompatibility. Electrospun membranes composed by helical and spiral shape fibers allow the achievement of large surface areas, leading to the improvement of the performance of this kind of systems. The moisture response, light modulated, wettability and the capability of orienting protein and cellulose crystals, opened a wide range of new applications to the shear casted films. Characterization by NMR, X-rays, tensile tests, AFM, and optical methods allowed detailed characterization of those soft cellulosic materials. In this work, special attention will be given to recent developments, including, among others, a moisture driven cellulosic motor and electro-optical devices.

  5. Cubic liquid crystalline nanoparticles: optimization and evaluation for ocular delivery of tropicamide. (United States)

    Verma, Purnima; Ahuja, Munish


    The purpose of this study was to investigate the potential of cubic liquid crystalline nanoparticles for ocular delivery of tropicamide. Ultrasound-assisted fragmentation of cubic liquid crystalline bulk phases resulted in cubic liquid crystalline nanoparticles employing Pluronic F127 as dispersant. The effects of process variables such as sonication time, sonication amplitude, sonication depth, and pre-mixing time on particle size and polydispersity index was investigated using central composite design. The morphology of tropicamide-loaded nanoparticles was found to be nearly cubical in shape by transmission electron microscopy observation. Further, small angle X-ray scattering experiment confirmed the presence of D and P phase cubic structures in coexistence. The optimized tropicamide-loaded cubic nanoparticles showed in vitro corneal permeation of tropicamide across isolated porcine cornea comparable to its commercial preparation, Tropicacyl®. Ocular tolerance was evaluated by Hen's egg-chorioallantoic membrane test and histological studies. The results of in vivo mydriatic response study demonstrated a remarkably higher area under mydriatic response curve (AUC0→1440 min) values of cubic nanoparticles over Tropicacyl® indicating better therapeutic value of cubic nanoparticles. Furthermore, tropicamide-loaded cubic nanoparticles exhibited prolonged mydriatic effect on rabbits as compared to commercial conventional aqueous ophthalmic solution.

  6. A new series of two-ring-based side chain liquid crystalline polymers: synthesis and mesophase characterization

    CSIR Research Space (South Africa)

    Reddy, GSM


    Full Text Available A new series of side chain liquid crystalline polymers containing a core, a butamethylenoxy spacer, ester groups, and terminal alkoxy groups were synthesised and their structures were confirmed. The core was constructed with two phenyl rings...

  7. Investigation of flow and microstructure in rheometric and processing flow conditions for liquid crystalline pitch (United States)

    Kundu, Santanu

    The microstructure development within mesophase pitch-based carbon materials depends on the flow history that the pitch is subjected to. Therefore, a fundamental understanding of flow and its influence on the microstructure is required to obtain carbon materials with desired properties. The objective of this research was to investigate the flow and microstructural behavior of a synthetic mesophase pitch (AR-HP) in rheometric and processing flow conditions. In addition, simulation studies were performed to establish a frame work for modeling the flow behavior of this complex material in different flow situations. The steady-shear viscosities obtained from a cone-plate rheometer during increasing rate-sweep experiments exhibited shear-thinning (Region I) and plateau (Region II) responses. However, the slope of the shear-thinning region was only about -0.2, much lower than -0.5 observed in some pitches and liquid-crystalline polymers. This difference could arise from the different molecular constituents of pitches. At higher shear rates, as measured from capillary rheometers, the viscosity values remained almost constant. The transient shear stress responses, as measured from cone-plate rheometer, exhibited nonmonotonic behavior as a function of applied strain at all shear rates and temperatures tested. After rheological experiments, the samples were collected by developing a new experimental protocol for preservation of the sample for microstructural analysis. Microstructural observations obtained from three orthogonal sections, reported for the first time in the literature, indicate that the local maximum in shear stress was due to yielding of initial microstructure. The microstructure became flow oriented with further shearing, and the structure size decreased with increasing shear rates. In addition to high-strain experiments, dynamic experiments were also performed in the linear viscoelastic region where no significant deformation of fluid takes place. The

  8. Silymarin glyceryl monooleate/poloxamer 407 liquid crystalline matrices: physical characterization and enhanced oral bioavailability. (United States)

    Lian, Ruyue; Lu, Yi; Qi, Jianping; Tan, Yanan; Niu, Mengmeng; Guan, Peipei; Hu, Fuqiang; Wu, Wei


    Silymarin, a mixture of flavonolignans extracted from the seeds of milk thistle, is used clinically as a hepatoprotector to treat liver injuries and chronic hepatitis. However, its therapeutic effect is compromised by its poor oral bioavailability due to the poor solubility and low permeability across intestinal epithelia. The main purpose of this study was to prepare silymarin glyceryl monooleate/poloxamer 407 liquid crystalline matrices (GMO/P407 LCM) to improve the oral bioavailability of silymarin. GMO/P407 LCMs were prepared by a melting/congealing method. The isotropic phenomenon observed under polarized light microscope confirmed the liquid crystalline structure at the junction of LCM and water. Both differential scanning calorimetry and X-ray diffraction analysis confirmed disappearance of silymarin crystallinity after incorporation into the LCMs. In vitro release of silymarin from LCMs was limited, whereas LCMs were readily degraded by lipase and released silymarin quickly and completely. Pharmacokinetic study in beagle dogs showed significantly increased peak concentration for silymarin GMO/P407 LCM, and, most importantly, a 3.46-fold increase in oral bioavailability as compared with Legalon®, a commercial silymarin formulation.

  9. Adsorption of lipid liquid crystalline nanoparticles on cationic, hydrophilic, and hydrophobic surfaces. (United States)

    Chang, Debby P; Jankunec, Marija; Barauskas, Justas; Tiberg, Fredrik; Nylander, Tommy


    Investigation of nonlamellar nanoparticles formed by dispersion of self-assembled lipid liquid crystalline phases is stimulated by their many potential applications in science and technology; resulting from their unique solubilizing, encapsulating, and space-dividing nature. Understanding the interfacial behavior of lipid liquid crystalline nanoparticles (LCNPs) at surfaces can facilitate the exploitation of such systems for a number of potentially interesting uses, including preparation of functional surface coatings and uses as carriers of biologically active substances. We have studied the adsorption of LCNP, based on phosphatidylcholine/glycerol dioleate and Polysorbate 80 as stabilizers, at different model surfaces by use of in situ ellipsometry. The technique allows time-resolved monitoring of the layer thickness and the amount adsorbed, thereby providing insights into the restructuring of the lipid nanoparticle upon adsorption. The effects of solvent condition, electrolyte concentration, particle size, and surface chemistry on adsorbed layer properties were investigated. Furthermore, the internal structures of the particles were investigated by cryo-transmission electron microscopy and small angle X-ray diffraction on the corresponding liquid crystalline phases in excess water. LCNPs are shown to form well-defined layers at the solid-liquid interface with a structure and coverage that are determined by the interplay between the self-assembly properties of the lipids and lipid surface interactions, respectively. At the hydrophobic surface, hydrophobic interaction results in a structural transition from the original LCNP morphology to a monolayer structure at the interface. In contrast, at cationic and hydrophilic surfaces, relaxation is a relatively slow process, resulting in much thicker adsorbed layers, with thickness and adsorption behavior that to a greater extent reflect the original bulk LCNP properties.

  10. Liquid-crystalline state of the wall-adjacent layers of some polar liquids

    National Research Council Canada - National Science Library

    Derjaguin, B.V; Popovskij, Yu.M; Altoiz, B.A


    ... of some polar liquids, of interfaces separating boundary layers with modified properties from the bulk liquid phase (1). The existence of such an interface was established, for example, in work (2) when studying the local values of viscosity in the wall-adjacent layers of sebacine-amyl ester. Figure 1 represents the dependence calculated according to data (2)...

  11. Highly tilted liquid crystalline materials possessing a direct phase transition from antiferroelectric to isotropic phase

    Energy Technology Data Exchange (ETDEWEB)

    Milewska, K.; Drzewiński, W. [Institute of Chemistry, Military University of Technology, 00-908 Warsaw (Poland); Czerwiński, M., E-mail: [Institute of Chemistry, Military University of Technology, 00-908 Warsaw (Poland); Dąbrowski, R. [Institute of Chemistry, Military University of Technology, 00-908 Warsaw (Poland); Piecek, W. [Institute of Applied Physics, Military University of Technology, 00-908 Warsaw (Poland)


    Pure compounds and multicomponent mixtures with a broad temperature range of high tilted liquid crystalline antiferroelectric phase and a direct phase transition from antiferroelectric to isotropic phase, were obtained. X-ray diffraction analysis confirms these kinds of materials form a high tilted anticlinic phase, with a fixed layer spacing and very weak dependency upon temperature, after the transition from the isotropic phase. Due to this, not only pure orthoconic antiferroelectric liquid crystals but also those with a moderate tilt should generate a good dark state. Furthermore, due to the increased potential for forming anticlinic forces, such materials could minimize a commonly observed asymmetry of a rise and fall switching times at a surface stabilized geometry. - Highlights: • The new class of liquid crystalline materials with the direct SmC{sub A}*. • Iso phase transition were obtained. • Materials possess the layer spacing fixed and very weak dependent upon temperature. • Smectic layers without shrinkage are observed. • A good dark state can be generate in SSAFLC.

  12. Probing the Texture of the Calamitic Liquid Crystalline Dimer of 4-(4-Pentenyloxybenzoic Acid

    Directory of Open Access Journals (Sweden)

    Maher A. Qaddoura


    Full Text Available The liquid crystalline dimer of 4-(4-pentenyloxybenzoic acid, a member of the n-alkoxybenzoic acid homologous series, was synthesized using potassium carbonate supported on alumina as catalyst. The acid dimer complex exhibited three mesophases; identified as nematic, smectic X1 and smectic X2. Phase transition temperatures and the corresponding enthalpies were recorded using differential scanning calorimetry upon both heating and cooling. The mesophases were identified by detailed texture observations by variable temperature polarized light microscopy. The nematic phase was distinguished by a fluid Schlieren texture and defect points (four and two brushes while the smectic phases were distinguished by rigid marble and mosaic textures, respectively.

  13. High diffraction efficiency polarization gratings recorded by biphotonic holography in an azobenzene liquid crystalline polyester

    DEFF Research Database (Denmark)

    Sánchez, C; Alcalá, R; Hvilsted, Søren


    High diffraction efficiencies have been achieved with polarization gratings recorded in thin films of an azobenzene side-chain liquid crystalline polyester by means of biphotonic processes. Efficiency values up to 30% have been reached after an induction period of 300 s and subsequent evolution...... is kept in darkness. Red light illumination of the erased film increases the recovered efficiency value and the recovery rate....... with the sample in darkness. These values are at least two orders of magnitude higher than those previously reported for biphotonic recording. The gratings can be erased with unpolarized blue light and partial recovery of the diffraction efficiency has been observed after the erasure process when the sample...

  14. Novel side-chain liquid crystalline polyester architecture for reversible optical storage

    DEFF Research Database (Denmark)

    Hvilsted, Søren; Andruzzi, Fulvio; Kulinna, Chrisian


    New side-chain liquid crystalline polyesters have been prepared by melt transesterification of diphenyl tetradecanedioate and a series of mesogenic 2-[omega-[4-[(4-cyanophenyl)azo]phenoxyl] alkyl]-1,3-propanediols, where the alkyl spacer is hexa-, octa-, and decamethylene in turn. The polyesters...... for the cyanoazobenzene mesogens calculated. FTIR is also utilized to follow the temperature-dependent erasure of the induced orientation. Optical storage properties of thin unoriented polyester films are examined through measurements of polarization anisotropy and holography. A resolution of over 5000 lines...

  15. Alignment engineering in liquid crystalline elastomers: Free-form microstructures with multiple functionalities (United States)

    Zeng, Hao; Wasylczyk, Piotr; Cerretti, Giacomo; Martella, Daniele; Parmeggiani, Camilla; Wiersma, Diederik S.


    We report a method to fabricate polymer microstructures with local control over the molecular orientation. Alignment control is achieved on molecular level in a structure of arbitrary form that can be from 1 to 100 μm in size, by fixing the local boundary conditions with micro-grating patterns. The method makes use of two-photon polymerization (Direct Laser Writing) and is demonstrated specifically in liquid-crystalline elastomers. This concept allows for the realization of free-form polymeric structures with multiple functionalities which are not possible to realize with existing techniques and which can be locally controlled by light in the micrometer scale.

  16. Alignment engineering in liquid crystalline elastomers: Free-form microstructures with multiple functionalities

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Hao; Cerretti, Giacomo; Wiersma, Diederik S., E-mail:, E-mail: [European Laboratory for Non Linear Spectroscopy (LENS), University of Florence, via Nello Carrara 1, 50019 Sesto Fiorentino (Italy); Wasylczyk, Piotr [European Laboratory for Non Linear Spectroscopy (LENS), University of Florence, via Nello Carrara 1, 50019 Sesto Fiorentino (Italy); Faculty of Physics, Institute of Experimental Physics, University of Warsaw, ul. Hoza 69, Warszawa 00-681 (Poland); Martella, Daniele [European Laboratory for Non Linear Spectroscopy (LENS), University of Florence, via Nello Carrara 1, 50019 Sesto Fiorentino (Italy); Dipartimento di Chimica “Ugo Schiff,” University of Florence, via della Lastruccia 3-13, 50019 Sesto Fiorentino (Italy); Parmeggiani, Camilla, E-mail:, E-mail: [European Laboratory for Non Linear Spectroscopy (LENS), University of Florence, via Nello Carrara 1, 50019 Sesto Fiorentino (Italy); CNR-INO, via Nello Carrara 1, 50019 Sesto Fiorentino (Italy)


    We report a method to fabricate polymer microstructures with local control over the molecular orientation. Alignment control is achieved on molecular level in a structure of arbitrary form that can be from 1 to 100 μm in size, by fixing the local boundary conditions with micro-grating patterns. The method makes use of two-photon polymerization (Direct Laser Writing) and is demonstrated specifically in liquid-crystalline elastomers. This concept allows for the realization of free-form polymeric structures with multiple functionalities which are not possible to realize with existing techniques and which can be locally controlled by light in the micrometer scale.

  17. Smectic ordering in nematic and smectic liquid-crystalline films probed by means of surface light scattering

    NARCIS (Netherlands)

    Böttger, A.; Frenkel, D.; Joosten, J.G.H.; Krooshof, G.


    We present the first results of experiments that measure the intensity of light scattered by capillary waves on the surface of free-standing liquid-crystalline thin films. The intensity of the scattered light provides information about the surface tension of the liquid-air interfaces and, more

  18. Light-Driven Liquid Crystalline Materials: From Photo-Induced Phase Transitions and Property Modulations to Applications. (United States)

    Bisoyi, Hari Krishna; Li, Quan


    Light-driven phenomena both in living systems and nonliving materials have enabled truly fascinating and incredible dynamic architectures with terrific forms and functions. Recently, liquid crystalline materials endowed with photoresponsive capability have emerged as enticing systems. In this Review, we focus on the developments of light-driven liquid crystalline materials containing photochromic components over the past decade. Design and synthesis of photochromic liquid crystals (LCs), photoinduced phase transitions in LC, and photoalignment and photoorientation of LCs have been covered. Photomodulation of pitch, polarization, lattice constant and handedness inversion of chiral LCs is discussed. Light-driven phenomena and properties of liquid crystalline polymers, elastomers, and networks have also been analyzed. The applications of photoinduced phase transitions, photoalignment, photomodulation of chiral LCs, and photomobile polymers have been highlighted wherever appropriate. The combination of photochromism, liquid crystallinity, and fabrication techniques has enabled some fascinating functional materials which can be driven by ultraviolet, visible, and infrared light irradiation. Nanoscale particles have been incorporated to widen and diversify the scope of the light-driven liquid crystalline materials. The developed materials possess huge potential for applications in optics, photonics, adaptive materials, nanotechnology, etc. The challenges and opportunities in this area are discussed at the end of the Review.

  19. Carrier transport simulation in a model liquid crystalline system with the biaxial Gay-Berne potential. (United States)

    Goto, Masanao; Takezoe, Hideo; Ishikawa, Ken


    In this paper, we performed carrier transport simulation to understand the unusual temperature dependence of the carrier mobility observed in nematic liquid crystals. For this purpose, we made a model liquid crystalline system consisting of biaxial Gay-Berne particles, and then we simulated hopping transport between these particles. The hopping rate was formulated suitably for the biaxial Gay-Berne particles based on the investigation of the electronic overlaps between actual aromatic molecules. The carrier transport simulation was performed by master equation method on the model system prepared by N-P-T ensemble Monte Carlo simulation. We reproduced gradual mobility increase in the nematic phase as a result of the change in the short range molecular order.

  20. Evaluation on the electrochemically deposited alkoxy thiourea as liquid crystalline semiconductor film (United States)

    Rahamathullah, Rafizah; Khairul, Wan M.


    A new class of liquid crystalline film of alkoxy thiourea which was successfully deposited on indium tin oxide (ITO) coated substrate via electrochemical deposition method. The relationship between liquid crystal molecular structure, phase transition temperature and electrical performance was evaluated. The mesomorphic properties were identified via polarized optic microscopy (POM) which displayed cholesteric phase and their corresponding transition enthalpies were respectively recorded at 20.25 kJ mol-1. The findings from the conductivity analysis revealed that the fabricated film exhibits good electrical performance with an increasing conductivity up to 0.2170 S cm-1 under maximum light intensity of 100 W m-2. Therefore, this proposed type of molecular framework has given an ideal indication to act as semiconductor materials and has opened wide potential for application in organic electronic devices.

  1. Temperature-Responsive Luminescent Solar Concentrators: Tuning Energy Transfer in a Liquid Crystalline Matrix. (United States)

    Sol, Jeroen A H P; Dehm, Volker; Hecht, Reinhard; Würthner, Frank; Schenning, Albertus P H J; Debije, Michael G


    Temperature-responsive luminescent solar concentrators (LSCs) have been fabricated in which the Förster resonance energy transfer (FRET) between a donor-acceptor pair in a liquid crystalline solvent can be tuned. At room temperatures, the perylene bisimide (PBI) acceptor is aggregated and FRET is inactive; while after heating to a temperature above the isotropic phase of the liquid crystal solvent, the acceptor PBI completely dissolves and FRET is activated. This unusual temperature control over FRET was used to design a color-tunable LSC. The device has been shown to be highly stable towards consecutive heating and cooling cycles, making it an appealing device for harvesting otherwise unused solar energy. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  2. Demixing by a Nematic Mean Field: Coarse-Grained Simulations of Liquid Crystalline Polymers

    Energy Technology Data Exchange (ETDEWEB)

    Ramírez-Hernández, Abelardo; Hur, Su-Mi; Armas-Pérez, Julio; Cruz, Monica; de Pablo, Juan


    Liquid crystalline polymers exhibit a particular richness of behaviors that stems from their rigidity and their macromolecular nature. On the one hand, the orientational interaction between liquid-crystalline motifs promotes their alignment, thereby leading to the emergence of nematic phases. On the other hand, the large number of configurations associated with polymer chains favors formation of isotropic phases, with chain stiffness becoming the factor that tips the balance. In this work, a soft coarse-grained model is introduced to explore the interplay of chain stiffness, molecular weight and orientational coupling, and their role on the isotropic-nematic transition in homopolymer melts. We also study the structure of polymer mixtures composed of stiff and flexible polymeric molecules. We consider the effects of blend composition, persistence length, molecular weight and orientational coupling strength on the melt structure at the nano-and mesoscopic levels. Conditions are found where the systems separate into two phases, one isotropic and the other nematic. We confirm the existence of non-equilibrium states that exhibit sought-after percolating nematic domains, which are of interest for applications in organic photovoltaic and electronic devices.

  3. Collagen films with stabilized liquid crystalline phases and concerns on osteoblast behaviors

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Minjian; Ding, Shan; Min, Xiang; Jiao, Yanpeng, E-mail:; Li, Lihua; Li, Hong; Zhou, Changren, E-mail:


    To duplicate collagen's in vivo liquid crystalline (LC) phase and investigate the relationship between the morphology of LC collagen and osteoblast behavior, a self-assembly method was introduced for preparing collagen films with a stabilized LC phase. The LC texture and topological structure of the films before and after stabilization were observed with polarizing optical microscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). The relationship between the collagen films and osteoblast behavior was studied with the 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide method, proliferation index detection, alkaline phosphatase measurements, osteocalcin assay, inverted microscopy, SEM observation, AFM observation, and cytoskeleton fluorescence staining. The results showed that the LC collagen film had continuously twisting orientations in the cholesteric phase with a typical series of arced patterns. The collagen fibers assembled in a well-organized orientation in the LC film. Compared to the non-LC film, the LC collagen film can promote cell proliferation, and increase ALP and osteocalcin expression, revealing a contact guide effect on osteoblasts. - Highlights: • Collagen film with liquid crystalline (LC) phase was observed by POM, SEM and AFM. • The effect of LC collagen film on osteoblasts behaviors was studied in detail. • LC collagen film promoted osteoblast proliferation and osteogenesis activity.

  4. Polarized Emission of Wholly Aromatic Bio-Based Copolyesters of a Liquid Crystalline Nature

    Directory of Open Access Journals (Sweden)

    Daisaku Kaneko


    Full Text Available A novel thermotropic liquid crystalline polymers poly{3-benzylidene amino-4-hydroxybenzoic acid (3,4-BAHBA-co-trans-4-hydroxycinnamic acid (4HCA: trans-coumaric acid} (Poly(3,4-BAHBA-co-4HCA, was synthesized by the thermal polycondensation of 4HCA and 3,4-BAHBA, which was synthesized by a reaction of 3-amino-4-hydroxybenzoic acid (3,4-AHBA with benzaldehyde. When the 4HCA compositions of Poly(3,4-BAHBA-co-4HCAs were above 55 mol%, the copolymers showed a nematic, liquid crystalline phase. Differential scanning calorimetry (DSC measurements of the copolymers showed a high glass transition temperature of more than 100 °C, sufficient for use in engineering plastics. Furthermore, the copolymers showed photoluminescence in an N-methylpyrrolidone (NMP solution under ultraviolet (UV light with a wavelength of 365 nm. Oriented film of Poly(3,4-BAHBA-co-4HCA with a 4HCA composition of 75 mol% emitted polarized light, which was confirmed by fluorescent spectroscopy equipped with parallel and crossed polarizers.

  5. Demixing by a Nematic Mean Field: Coarse-Grained Simulations of Liquid Crystalline Polymers

    Directory of Open Access Journals (Sweden)

    Abelardo Ramírez-Hernández


    Full Text Available Liquid crystalline polymers exhibit a particular richness of behaviors that stems from their rigidity and their macromolecular nature. On the one hand, the orientational interaction between liquid-crystalline motifs promotes their alignment, thereby leading to the emergence of nematic phases. On the other hand, the large number of configurations associated with polymer chains favors formation of isotropic phases, with chain stiffness becoming the factor that tips the balance. In this work, a soft coarse-grained model is introduced to explore the interplay of chain stiffness, molecular weight and orientational coupling, and their role on the isotropic-nematic transition in homopolymer melts. We also study the structure of polymer mixtures composed of stiff and flexible polymeric molecules. We consider the effects of blend composition, persistence length, molecular weight and orientational coupling strength on the melt structure at the nano- and mesoscopic levels. Conditions are found where the systems separate into two phases, one isotropic and the other nematic. We confirm the existence of non-equilibrium states that exhibit sought-after percolating nematic domains, which are of interest for applications in organic photovoltaic and electronic devices.

  6. Liquid crystalline systems containing Vitamin E TPGS for the controlled transdermal nicotine delivery

    Directory of Open Access Journals (Sweden)

    Lívia Neves Borgheti-Cardoso

    Full Text Available ABSTRACT Transdermal nicotine patches have been used in smoking cessation therapy, suggested for the treatment of skin disorders with eosinophilic infiltration and have been found to improve attention performance in patients with Alzheimer's disease and age-associated memory impairment. However, skin irritation with extended patch use is still a problem. The aim of this work was to develop a simple to prepare liquid crystalline system containing vitamin E TPGS that would be able to control nicotine delivery and reduce irritation and sensitization problems. The liquid crystalline phases were macroscopically characterized by visual analysis and examined microscopically under a polarized light microscope. Topical and transdermal delivery of nicotine were investigated in vitro using porcine ear skin mounted on a Franz diffusion cell. Nicotine skin permeation from the developed cubic phase followed zero-order kinetics (r = 0.993 and was significantly enhanced after 12 h when compared to the control formulation (nicotine solution (p < 0.05 (138.86 ± 20.44 and 64.91 ± 4.06 μg/cm2, respectively. Cubic phase was also able to target viable skin layers in comparison to control solution (8.18 ± 1.89 and 2.63 ± 2.51 μg/cm2, respectively. Further studies to evaluate skin sensitization and irritation are now necessary.

  7. Controlling the Spatial Organization of Liquid Crystalline Nanoparticles by Composition of the Organic Grafting Layer. (United States)

    Wójcik, Michał M; Olesińska, Magdalena; Sawczyk, Michał; Mieczkowski, Józef; Górecka, Ewa


    Understanding how the spatial ordering of liquid crystalline nanoparticles can be controlled by different factors is of great importance in the further development of their photonic applications. In this paper, we report a new key parameter to control the mesogenic behavior of gold nanoparticles modified by rodlike thiols. An efficient method to control the spatial arrangement of hybrid nanoparticles in a condensed state is developed by changing the composition of the mesogenic grafting layer on the surface of the nanoparticles. The composition can be tuned by different conditions of the ligand exchange reaction. The thermal and optical behavior of the mesogenic and promesogenic ligands were investigated by using differential scanning calorimetry (DSC) and hot-stage polarized optical microscopy. The chemical structure of the synthesized hybrid nanoparticles was characterized by (1) H NMR spectroscopy, thermogravimetric analysis (TGA), XPS, and elemental analysis, whereas the superstructures were examined by small-angle X-ray diffraction (SAXSRD) analysis. Structural studies showed that the organic sublayer made of mesogenic ligands is denser with an increasing the average ligand number, thereby separating the nanoparticles in the liquid crystalline phases, which changes the parameters of these phases. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Characterisation of bicontinuous cubic liquid crystalline systems of phytantriol and water using cryo field emission scanning electron microscopy (cryo FESEM). (United States)

    Rizwan, S B; Dong, Y-D; Boyd, B J; Rades, T; Hook, S


    Cubosomes are a novel lipid particulate delivery system currently being investigated for drug delivery purposes. The present study investigates bicontinuous cubic liquid crystalline systems (bulk phase and cubosomes) formed by phytantriol and water using cryo field emission scanning electron microscopy (cryo FESEM). Previously cubosomes have been characterized by cryo transmission electron microscopy (cryo TEM) with small angle X-ray diffraction (SAXS) confirming the bicontinuous liquid crystalline type. Bulk cubic phase and cubosomes were prepared from phytantriol and Pluronic F127 and analysed using cryo FESEM and SAXS. The micrographs showed the cubic phase had a tortuous, bicontinuous nature with a non-intersecting network of water channels. The cubosomes also show the same underlying tortuous structure entirely consistent with that of the bulk cubic phase and closely resemble the mathematical description of cubosomes described using nodal surface representation. The structure of both systems was confirmed using SAXS as a bicontinuous cubic liquid crystalline phase with Pn3m geometry. Cryo FESEM provides valuable insights into the morphological features of bicontinuous cubic liquid crystalline systems. The unique details shown provide strength to support the nodal surface representation of bicontinuous cubic liquid crystalline systems. Cryo FESEM provides a new technique to complement cryo TEM and SAXS for investigating their structure and function.

  9. The effect of liquid crystalline structures on antiseizure properties of aqueous solutions of ethoxylated alcohols. (United States)

    Sulek, Marian Wlodzimierz; Bak, Anna


    Aqueous solutions of ethoxylated alcohols which form lyotropic liquid crystals at high concentrations (40-80%) were selected as model lubricating substances. Microscopic studies under polarized light and viscosity measurements were carried out in order to confirm the presence of liquid crystalline structures in the case of alcohol solutions with ethoxylation degrees of 3, 5, 7 and 10. Microscopic images and viscosity coefficient values characteristic of various mesophases were obtained. As expected, the viscosity of LLCs decreases considerably with an increase in shearing rate which is characteristic of liquid crystals being non-Newtonian liquids. Antiseizure properties were determined by means of a four-ball machine (T-02 Tester) and characterized by scuffing load (P(t)), seizure load (P(oz)) and limiting pressure of seizure (p(oz)). Alcohol ethoxylates forming mesophases in aqueous solutions have the strongest effect on the P(t) values which are several times higher than those measured in the presence of water. Ethoxylates with higher degrees of ethoxylation exhibit higher values of scuffing load. Those changes have been interpreted as a result of higher cloud points at which those compounds lose their amphiphilic properties. In general, the presence of mesophases in the bulk phase and particularly in the surface phase may lead to the formation of a lubricant film which separates the frictionally cooperating elements of a friction pair. The antiseizure efficiency of alcohol solutions is highest up to the load value which does not exceed the scuffing load value.

  10. The Effect of Liquid Crystalline Structures on Antiseizure Properties of Aqueous Solutions of Ethoxylated Alcohols (United States)

    Sulek, Marian Wlodzimierz; Bak, Anna


    Aqueous solutions of ethoxylated alcohols which form lyotropic liquid crystals at high concentrations (40–80%) were selected as model lubricating substances. Microscopic studies under polarized light and viscosity measurements were carried out in order to confirm the presence of liquid crystalline structures in the case of alcohol solutions with ethoxylation degrees of 3, 5, 7 and 10. Microscopic images and viscosity coefficient values characteristic of various mesophases were obtained. As expected, the viscosity of LLCs decreases considerably with an increase in shearing rate which is characteristic of liquid crystals being non-Newtonian liquids. Antiseizure properties were determined by means of a four-ball machine (T-02 Tester) and characterized by scuffing load (Pt), seizure load (Poz) and limiting pressure of seizure (poz). Alcohol ethoxylates forming mesophases in aqueous solutions have the strongest effect on the Pt values which are several times higher than those measured in the presence of water. Ethoxylates with higher degrees of ethoxylation exhibit higher values of scuffing load. Those changes have been interpreted as a result of higher cloud points at which those compounds lose their amphiphilic properties. In general, the presence of mesophases in the bulk phase and particularly in the surface phase may lead to the formation of a lubricant film which separates the frictionally cooperating elements of a friction pair. The antiseizure efficiency of alcohol solutions is highest up to the load value which does not exceed the scuffing load value. PMID:20162010

  11. Influence of liquid crystalline phases on the tunability of a random laser (United States)

    Trull, José; Salud, Josep; Diez-Berart, Sergio; López, David O.


    In this paper, we report the temperature behavior of an optimized disordered photonic system-based liquid crystal by means of heat capacity and refractive index measurements. The scattering system is formed by a porous borosilicate glass random matrix (about 60%) infiltrated with a smectogenic liquid crystal (about 16%) and a small amount of laser dye (0.1%). The rest of the scattering system is about 24% air, giving rise to a high refractive index contrast scattering system. Such a system has the functionality to change the refractive index contrast with temperature due to the liquid crystal temperature behavior. The system, optically pumped by the second harmonic of a Q -switched Nd:YAG pulsed laser working at 532 nm, exhibits random laser action, the threshold of which depends upon the liquid crystalline mesophase. Temperatures of existence of the smectic-B phase correspond to the most optimized random laser. In such a mesophase, the transport mean free path has been determined as about 16 μm in a coherent backscattering experiment.

  12. Silica nanoparticle stabilization of liquid crystalline lipid dispersions: impact on enzymatic digestion and drug solubilization. (United States)

    Bhatt, Achal B; Barnes, Timothy J; Prestidge, Clive A


    The high internal surface area and drug solubilizing capacity of liquid crystal lipids makes them promising oral drug delivery systems. Pluronic F127 is typically used to disperse highly viscous cubic liquid crystal lipids into cubosomes; however, such copolymers alter the internal structure and provide little control over enzymatic digestion. This study aimed to use hydrophilic silica nanoparticles to stabilize glyceryl monooleate (GMO) cubosomes prepared by ultrasonication. We investigate the influence of silica nanoparticles size and concentration on the physical (colloidal) and chemical (enzymatic digestion) stability, as well as in vitro solubilization of cinnarizine as a poorly soluble model drug. Silica stabilized nanostructured liquid crystal dispersions (120 nm to150 nm in diameter and zeta potentials of-30 mV to -60 mV) were successfully prepared with excellent long-term stability (Silica stabilized GMO cubosomes demonstrated reduced enzymatic digestion compared to pluronic F127 stabilized cubosomes. This reduced digestion was attributed to a combination of adsorbed silica nanoparticles acting as a physical barrier and excess dispersed silica adsorbing/scavenging the lipase enzyme. Under simulated intestinal digestion conditions, silica stabilized GMO cubosomes showed a greater solubilization capacity for cinnarizine, which precipitated in non-crystalline form, in comparison to pure drug suspensions or pluronic F127 stabilized GMO cubosomes. Silica nanoparticle stabilized GMO liquid crystal dispersions are a promising oral delivery vehicle.

  13. Characterization and in vitro permeation study of microemulsions and liquid crystalline systems containing the anticholinesterase alkaloidal extract from Tabernaemontana divaricata

    DEFF Research Database (Denmark)

    Chaiyana, Wantida; Rades, Thomas; Okonogi, Siriporn


    The aims of the present study were to characterize the microstructure and study the skin permeation enhancement of formulations containing the alkaloidal extract from Tabernaemontana divaricata. The extract was loaded in the formulations composed of Zingiber cassumunar oil, Triton X-114, ethanol...... was used in the permeation study. The liquid crystalline and microemulsion systems significantly increased the transdermal delivery of the extract within 24h. It was concluded that the alkaloidal extract from T. divaricata stem loaded in liquid crystalline or microemulsion systems comprising Z. cassumunar...

  14. Bio-inspired production of chitosan/chitin films from liquid crystalline suspensions. (United States)

    João, Carlos F C; Echeverria, Coro; Velhinho, Alexandre; Silva, Jorge C; Godinho, Maria H; Borges, João P


    Inspired by chitin based hierarchical structures observed in arthropods exoskeleton, this work reports the capturing of chitin nanowhiskers' chiral nematic order into a chitosan matrix. For this purpose, highly crystalline chitin nanowhiskers (CTNW) with spindle-like morphology and average aspect ratio of 24.9 were produced by acid hydrolysis of chitin. CTNW were uniformly dispersed at different concentrations in aqueous suspensions. The suspensions liquid crystalline phase domain was determined by rheological measurements and polarized optical microscopy (POM). Chitosan (CS) was added to the CTNW isotropic, biphasic and anisotropic suspensions and the solvent was evaporated to allow films formation. The Films' morphologies as well as the mechanical properties were explored. A correlation between experimental results and a theoretical model, for layered matrix' structures with fibers acting as a reinforcement agent, was established. The results evidence the existence of two different layered structures, one formed by chitosan layers induced by the presence of chitin and another formed by chitin nanowhiskers layers. By playing on the ratio chitin/chitosan one layered structure or the other can be obtained allowing the tunning of materials' mechanical properties. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Are liquid crystalline properties of nucleosomes involved in chromosome structure and dynamics? (United States)

    Livolant, Françoise; Mangenot, Stéphanie; Leforestier, Amélie; Bertin, Aurélie; Frutos, Marta de; Raspaud, Eric; Durand, Dominique


    Nucleosome core particles correspond to the structural units of eukaryotic chromatin. They are charged colloids, 101 Angstrom in diameter and 55 Angstrom in length, formed by the coiling of a 146/147 bp DNA fragment (50 nm) around the histone protein octamer. Solutions of these particles can be concentrated, under osmotic pressure, up to the concentrations found in the nuclei of living cells. In the presence of monovalent cations (Na(+)), nucleosomes self-assemble into crystalline or liquid crystalline phases. A lamello-columnar phase is observed at 'low salt' concentrations, while a two-dimensional hexagonal phase and a three-dimensional quasi-hexagonal phase form at 'high salt' concentrations. We followed the formation of these phases from the dilute isotropic solutions to the ordered phases by combining cryoelectron microscopy and X-ray diffraction analyses. The phase diagram is presented as a function of the monovalent salt concentration and applied osmotic pressure. An alternative method to condense nucleosomes is to induce their aggregation upon addition of divalent or multivalent cations (Mg(2+), spermidine(3+) and spermine(4+)). Ordered phases are also found in the aggregates. We also discuss whether these condensed phases of nucleosomes may be relevant from a biological point of view.

  16. High-Density Liquid-Crystalline Polymer Brushes Formed by Surface Segregation and Self-Assembly. (United States)

    Mukai, Koji; Hara, Mitsuo; Nagano, Shusaku; Seki, Takahiro


    High-density polymer brushes on substrates exhibit unique properties and functions stemming from the extended conformations due to the surface constraint. To date, such chain organizations have been mostly attained by synthetic strategies of surface-initiated living polymerization. We show herein a new method to prepare a high-density polymer brush architecture using surface segregation and self-assembly of diblock copolymers containing a side-chain liquid-crystalline polymer (SCLCP). The surface segregation is attained from a film of an amorphous base polymer (polystyrene, PS) containing a minor amount of a SCLCP-PS diblock copolymer upon annealing above the glass-transition temperature. The polystyrene portion of the diblock copolymer can work as a laterally mobile anchor for the favorable self-assembly on the polystyrene base film. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Synthesis, Characterization and Photoinduction of Optical Anisotropy in Liquid Crystalline Diblock Azo-Copolymers

    DEFF Research Database (Denmark)

    Forcén, P; Oriol, L; Sánchez, C


    behavior similar to that of the azo homopolymers. Thin films of these copolymers were characterized by transmission elevtron microscopy (TEM). A lamellar nanostructure was observed for azo content down to 20 wt %, while no structure is observed for the copolymer with a 7% azo content. The optical......Diblock copolymers with polymethyl methacrylate and side chain liquid crystalline WC) azopolymethacrylate blocks were synthesized by atom transfer radical polymerization (ATRP). The azobeazene content in these copolymers ranges from 52 to 7 wt %. For an azo conteat dowri to 20% they exhibit a LC...... the homopolymer to the copolymers. Photoinduced azo orientation perpendicular to the 488 nm light polarization was found in aH the polymers. The orientational order parameter is very similar in the homopolymer and in the block copolymers with an azo content down to 20 wt %, while it is much lower in the random...

  18. Unsymmetrical banana-shaped liquid crystalline compounds 1 derived from 2,7-dihydroxynaphtalene

    Directory of Open Access Journals (Sweden)

    Simion Aurel


    Full Text Available The synthesis and characterization of new bent-core asymmetric compounds derived from 2,7-dihydroxynaphtalene with various connecting groups between the aromatic rings and alkyloxy terminal substituents at the end of the long arm are presented. As calamitic promesogenic units some 1,4 - disubstituted phenylene rings with azo or ester linkage between them have been used. The synthetic strategies to obtain the final esteric derivatives involved the esterification of 7-(benzyloxynaphthalen-2-ol with 4-(4-alkyloxyphenylazobenzoyl chlorides or with 4-((4- (alkyloxybenzoyloxybenzoic acids in the presence of DCCI and DMAP. The mesomorphic properties have been assigned by optical polarizing microscopy and differential scanning calorimetry. All the compounds showed mesomorphic properties of enantiotropic or monotropic type, the liquid crystalline behavior depending on the linking group between the phenylene rings. Thermogravimetric studies evidenced that all compounds were stable in the range of the existence of mesophases.

  19. Crystalline architectures at the air-liquid interface: From nucleation to engineering

    DEFF Research Database (Denmark)

    Rapaport, H.; Kuzmenko, I.; Kjær, K.


    for optoelectronics requires knowledge and control of nanoarchitectures from the very early stages of self-organization. This requirement touches upon the control of nucleation, growth, morphology and structure of crystals, particularly at interfaces. The recent development of various methods for the elucidation...... with water-soluble ions or molecules from the aqueous subphase. In this review much use is made of grazing incidence X-ray diffraction (GIXD) using synchrotron radiation that provides structural information at the subnanometer scale of crystalline films at the air-liquid interface [1,2]. The topics described...... here shall encompass the spontaneous separation of racemates of amphiphilic molecules into enantiomorphous two-dimensional (2D) domains, the formation of alkane multilayers, the assembly of trilayers containing interdigitated molecules, the self-organization of supramolecular thin film architectures...

  20. Azobenzene side-chain liquid crystalline polyesters with outstanding optical storage properties

    DEFF Research Database (Denmark)

    Hvilsted, Søren; Pedersen, M; Holme, NCR


    A flexible azobenzene side-chain liquid crystalline (SCLC) polyester architecture employed for reversible optical storage is described. The modular design allows four structural parameters to be individually modified. These parameters: i- the methylene side-chain spacer length, ii- the substituent......, information can be recorded either through polarization holography or as direct computer generated pattern (grey tones). Thus polarization holography results in high diffraction efficiency (> 50%) and high storage density (> 5000 lines/mm interference gratings) lasting presently well over 5 years without any......, the observed surface roughness is strongly dependent on the laser polarization. Polarization Fourier-Transform infrared studies of laser induced segmental motion in selectively deuterated SCLC cyanoazobenzene polyesters have revealed that not only the azobenzene chromophores but also main-chain and side...

  1. Diketopyrrolopyrrole Columnar Liquid-Crystalline Assembly Directed by Quadruple Hydrogen Bonds. (United States)

    Soberats, Bartolome; Hecht, Markus; Würthner, Frank


    A diketopyrrolopyrrole (DPP) dye self-assembles via a unique hydrogen-bonding motif into an unprecedented columnar liquid-crystalline (LC) structure. X-ray and polarized FTIR experiments reveal that the DPPs organize into a one-dimensional assembly with the chromophores oriented parallel to the columnar axis. This columnar structure is composed of two π-π-stacked DPP dimers with mirror-image configurations that stack alternately through quadruple hydrogen bonding by 90° rotation. This exotic packing is dictated by the complementarity between H-bonds and the steric demands of the wedge-shaped groups attached at the core. This novel LC supramolecular material opens a new avenue of research on DPP dye assemblies with photofunctional properties tailored by H-bonding networks. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Immune cell activation from multivalent interactions with liquid-crystalline polycation-DNA complexes (United States)

    Schmidt, Nathan; Jin, Fan; Lande, Roberto; Curk, Tine; Xian, Wujing; Frasca, Loredana; Dobnikar, Jure; Frenkel, Daan; Gilliet, Michel; Wong, Gerard


    Microbial DNA can trigger type I interferon (IFN) production in plasmacytoid cells (pDCs) by binding to endosomal toll-like receptor 9 (TLR9). TLR9 in pDCs do not normally respond to self-DNA, but in certain autoimmune diseases self-DNA can complex with the polycationic antimicrobial peptide LL37 into condensed structures which allow DNA to access endosomal compartments and stimulate TLR9 in pDCs. We use x-ray studies and cell measurements of IFN secretion by pDCs to show that a broad range of polycation-DNA complexes stimulate pDCs and elucidate the criterion for high IFN production. Furthermore, we show via experiments and computer simulations that the distinguishing factor for why certain complexes activate pDCs while others do not is the self-assembled structure of the liquid-crystalline polycation-DNA complex.

  3. Enhancement in Mechanical and Shape Memory Properties for Liquid Crystalline Polyurethane Strengthened by Graphene Oxide

    Directory of Open Access Journals (Sweden)

    Yueting Li


    Full Text Available Conventional shape memory polymers suffer the drawbacks of low thermal stability, low strength, and low shape recovery speed. In this study, main-chain liquid crystalline polyurethane (LCPU that contains polar groups was synthesized. Graphene oxide (GO/LCPU composite was fabricated using the solution casting method. The tensile strength of GO/LCPU was 1.78 times that of neat LCPU. In addition, shape recovery speed was extensively improved. The average recovery rate of sample with 20 wt % GO loading was 9.2°/s, much faster than that of LCPU of 2.6°/s. The enhancement in mechanical property and shape memory behavior could be attributed to the structure of LCPU and GO, which enhanced the interfacial interactions between GO and LCPU.

  4. Crystalline titania nanoparticles synthesized in nonpolar Lα lecithin liquid-crystalline media in one stage at ambient conditions. (United States)

    Shchipunov, Yury; Krekoten, Anna


    High-temperature modification of titania in the form of nanoplatelets is synthesized fast in one step at ambient conditions without any additional treatment like aging or calcination. Lecithin, which is the main component of lipid matrix of biological membranes, is first used as a structure-driven template. It is demonstrated that this natural surfactant can self-organize into lamellar L(α) mesophase when small amounts of water are admixed in its solution in nonpolar solvent. The water locating mainly in lecithin polar region as hydration shell at this concentration triggers the hydrolysis-condensation reactions after the precursor addition that results in instantaneous titania formation in the form of crystalline nanoparticles. Planar lamellar sheets serve as the template specifying its crystallinity. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Tuning the defect configurations in nematic and smectic liquid crystalline shells. (United States)

    Liang, Hsin-Ling; Noh, JungHyun; Zentel, Rudolf; Rudquist, Per; Lagerwall, Jan P F


    Thin liquid crystalline shells surrounding and surrounded by aqueous phases can be conveniently produced using a nested capillary microfluidic system, as was first demonstrated by Fernandez-Nieves et al. in 2007. By choosing particular combinations of stabilizers in the internal and external phases, different types of alignment, uniform or hybrid, can be ensured within the shell. Here, we investigate shells in the nematic and smectic phases under varying boundary conditions, focusing in particular on textural transformations during phase transitions, on the interaction between topological defects in the director field and inclusions in the liquid crystal (LC), and on the possibility to relocate defects within the shell by rotating the shell in the gravitational field. We demonstrate that inclusions in a shell can seed defects that cannot form in a pristine shell, adding a further means of tuning the defect configuration, and that shells in which the internal aqueous phase is not density matched with the LC will gently rearrange the internal structure upon a rotation that changes the influence of gravity. Because the defects can act as anchor points for added linker molecules, allowing self-assembly of adjacent shells, the various arrangements of defects developing in these shells and the possibility of tuning the result by modifying boundary conditions, LC phase, thickness and diameter of the shell or applying external forces make this new LC configuration very attractive.

  6. Generation of liquid crystallinity from a Td-symmetry central unit. (United States)

    Sayed, Sayed Mir; Lin, Bao-Ping; Yang, Hong


    A series of new columnar liquid crystals containing an adamantane central unit with its four bridgehead positions partially or fully decorated with different numbers (1-4) of 3,4,5-tris(dodecyloxy)phenyl carbamoyl groups were designed and investigated carefully to explore the structure-property correlations. The molecular structures and mesomorphic properties of the DLCs were characterized by (1)H-NMR, (13)C-NMR, IR, UV-vis, POM, DSC and XRD. It was found that the mesophase symmetry and thermal stability were extremely dependent on the structures of the adamantane derivatives. No mesophase was observed for the 1-adamantanecarboxylic acid derivative ADLC1, while two different mesophases were observed for ADLC2, a 1,3-disubstituted derivative functionalized with two 3,4,5-tris(dodecyloxy)phenyl carbamoyl groups at two symmetric bridgehead positions. At lower temperature ADLC2 exhibited a rectangular columnar phase, which switched to a square columnar phase possessing a wide temperature range. Similarly, a hexagonal columnar mesophase was observed for the bridgehead trisubstituted adamantane molecule ADLC3. Interestingly, the fully bridgehead-functionalized 1,3,5,7-tetrasubstituted adamantane compound ADLC4 completely lost liquid crystallinity.


    NARCIS (Netherlands)

    Doornkamp, Annette; VANEKENSTEIN, GORA; TAN, YY


    The photoinitiated polymerization of the liquid crystalline (LC) diacrylate monomer 1,4-(-2-methyl phenylene)-bis[4-(6-acryloyloxy-hexamethyleneoxy)benzoate] with T(k,n) = 85-degrees-C and T(i) = 118-degrees-C, was studied by d.s.c. at various temperatures under different conditions. In the

  8. The effect of calcining temperature on the properties of 0-3 piezoelectric composites of PZT and a liquid crystalline thermosetting polymer

    NARCIS (Netherlands)

    Ende, D.A. van den; Groen, W.A.; Zwaag, S. van der


    We report on the optimisation of a recently developed high performance 0-3 piezoelectric composite comprising of the piezoelectric Lead Zirconate Titanate (PZT) powder and a liquid crystalline thermosetting matrix polymer (LCT). The matrix polymer is a liquid crystalline polymer comprising of an

  9. Liquid-crystalline rigid-core semiconductor oligothiophenes: influence of molecular structure on phase behaviour and thin-film properties. (United States)

    Melucci, Manuela; Favaretto, Laura; Bettini, Christian; Gazzano, Massimo; Camaioni, Nadia; Maccagnani, Piera; Ostoja, Paolo; Monari, Magda; Barbarella, Giovanna


    The design, synthesis and properties of liquid-crystalline semiconducting oligothiophenes containing dithienothiophene (DTT), benzothiadiazole (BTZ) and carbazole (CBZ) rigid cores are described. The effect of molecular structure (shape, size and substitution) on their thermal behaviour and electrical properties has been investigated. Polarised optical microscopy (POM) and differential scanning calorimetry (DSC) analyses have revealed highly ordered smectic mesophases for most of the newly synthesised compounds. X-ray diffraction (XRD) studies performed at various temperatures have shown that the smectic order is retained in the crystalline state upon cooling across the transition temperature, affording cast films with a more favourable morphology for FET applications.

  10. Phase biaxiality in nematic liquid crystalline side-chain polymers of various chemical constitutions. (United States)

    Severing, Kirsten; Stibal-Fischer, Elke; Hasenhindl, Alfred; Finkelmann, Heino; Saalwächter, Kay


    In a previous deuterium NMR study conducted on a liquid crystalline (LC) polymer with laterally attached book-shaped molecules as the mesogenic moiety, we have revealed a biaxial nematic phase below the conventional uniaxial nematic phase (Phys. Rev. Lett. 2004, 92, 125501). To elucidate details of its formation, we here report on deuterium NMR experiments that have been conducted on different types of LC side-chain polymers as well as on mixtures with low-molar-mass mesogens. Different parameters that affect the formation of a biaxial nematic phase, such as the geometry of the attachment, the spacer length between the polymer backbone and the mesogenic unit, as well as the polymer dynamics, were investigated. Surprisingly, also polymers with terminally attached mesogens (end-on polymers) are capable of forming biaxial nematic phases if the flexible spacer is short and thus retains a coupling between the polymer backbone and the LC phase. Furthermore, the most important parameter for the formation of a biaxial nematic phase is the dynamics of the polymer backbone, as the addition of a small percentage of low molar mass LC to the biaxial nematic polymer from the original study served to shift both the glass transition and the appearance of detectable biaxiality in a very similar fashion. Plotting different parameters for the investigated systems as a function of T/Tg also reveals the crucial role of the dynamics of the polymer backbone and hence the glass transition.

  11. Lanthanide phytanates: liquid-crystalline phase behavior, colloidal particle dispersions, and potential as medical imaging agents. (United States)

    Conn, Charlotte E; Panchagnula, Venkateswarlu; Weerawardena, Asoka; Waddington, Lynne J; Kennedy, Danielle F; Drummond, Calum J


    Lanthanide salts of phytanic acid, an isoprenoid-type amphiphile, have been synthesized and characterized. Elemental analysis and FTIR spectroscopy were used to confirm the formed product and showed that three phytanate anions are complexed with one lanthanide cation. The physicochemical properties of the lanthanide phytanates were investigated using DSC, XRD, SAXS, and cross-polarized optical microscopy. Several of the hydrated salts form a liquid-crystalline hexagonal columnar mesophase at room temperature, and samarium(III) phytanate forms this phase even in the absence of water. Select lanthanide phytanates were dispersed in water, and cryo-TEM images indicate that some structure has been retained in the dispersed phase. NMR relaxivity measurements were conducted on these systems. It has been shown that a particulate dispersion of gadolinium(III) phytanate displays proton relaxivity values comparable to those of a commercial contrast agent for magnetic resonance imaging and a colloidal dispersion of europium(III) phytanate exhibits the characteristics of a fluorescence imaging agent.

  12. Synthesis and characterization of liquid crystalline polyester/graphene and a study of their properties. (United States)

    Hu, Wu-Quan; Zhu, Zong-Zhen; Jin, Jun; Dong, Zheng-Ping; Zhong, Xing; Zhou, Jing-Hui; Da, Shi-Jun; Li, Rong


    A new rod-like thermotropic liquid crystalline polyester (TLCP) material and its nanocomposites based on different concentrations of graphene were synthesized by in-situ high-temperature solution polymerization. The resulting nanocomposites were characterized using XRD, microscopic analysis (POM, SEM, and TEM), spectroscopic analysis (FT-IR, UV-Vis, and fluorescence), and thermal analysis (TGA and DSC). The XRD and POM methods showed that the composite materials exhibited only the nematic phase. The TEM images revealed that the graphene were distributed in the polymer with sizes ranging from 100 to 200 nm. The absorption spectroscopy data showed that the electronic properties of graphene were mostly retained without damaging their two-dimensional electronic properties, together with the analysis of the maximum absorption spectrum and concentration of the composites in terms of the Lambert-Beer law. The fluorescence from the TLCP moiety was almost completely quenched and red shifted by graphene, indicating that the linkage mode facilitated effective energy and electron transfer between the rod-like TLCP and the extended pi-system of graphene. Therefore, this novel nanocomposite material exhibits excellent thermal properties based on the thermogravimetric analysis.

  13. Copper-Coated Liquid-Crystalline Elastomer via Bioinspired Polydopamine Adhesion and Electroless Deposition. (United States)

    Frick, Carl P; Merkel, Daniel R; Laursen, Christopher M; Brinckmann, Stephan A; Yakacki, Christopher M


    This study explores the functionalization of main-chain nematic elastomers with a conductive metallic surface layer using a polydopamine binder. Using a two-stage thiol-acrylate reaction, a programmed monodomain is achieved for thermoreversible actuation. A copper layer (≈155 nm) is deposited onto polymer samples using electroless deposition while the samples are in their elongated nematic state. Samples undergo 42% contraction when heated above the isotropic transition temperature. During the thermal cycle, buckling of the copper layer is seen in the direction perpendicular to contraction; however, transverse cracking occurs due to the large Poisson effect experienced during actuation. As a result, the electrical conductivity of the layer reduced quickly as a function of thermal cycling. However, samples do not show signs of delamination after 25 thermal cycles. These results demonstrate the ability to explore multifunctional liquid-crystalline composites using relatively facile synthesis, adhesion, and deposition techniques. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Controlling domain orientation of liquid crystalline block copolymer in thin films through tuning mesogenic chemical structures

    Energy Technology Data Exchange (ETDEWEB)

    Xie, He-Lou [Institute for Molecular Engineering, The University of Chicago, Chicago Illinois 60637; Li, Xiao [Institute for Molecular Engineering, The University of Chicago, Chicago Illinois 60637; Ren, Jiaxing [Institute for Molecular Engineering, The University of Chicago, Chicago Illinois 60637; Bishop, Camille [Institute for Molecular Engineering, The University of Chicago, Chicago Illinois 60637; Arges, Christopher G. [Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge Louisiana 70803 USA; Nealey, Paul F. [Institute for Molecular Engineering, The University of Chicago, Chicago Illinois 60637; Materials Science Division, Argonne National Laboratory, Argonne Illinois 60439


    Controlling the macroscopic orientation of nanoscale periodic structures of amphiphilic liquid crystalline block copolymers (LC BCPs) is important to a variety of technical applications (e.g., lithium conducting polymer electrolytes). To study LC BCP domain orientation, a series of LC BCPs containing a poly(ethylene oxide) (PEO) block as a conventional hydrophilic coil block and LC blocks containing azobenzene mesogens is designed and synthesized. LC ordering in thin films of the BCP leads to the formation of highly ordered, microphase-separated nanostructures, with hexagonally arranged PEO cylinders. Substitution on the tail of the azobenzene mesogen is shown to control the orientation of the PEO cylinders. When the substitution on the mesogenic tails is an alkyl chain, the PEO cylinders have a perpendicular orientation to the substrate surface, provided the thin film is above a critical thickness value. In contrast, when the substitution on the mesogenic tails has an ether group the PEO cylinders assemble parallel to the substrate surface regardless of the film thickness value.

  15. Liquid-crystalline ordering of antimicrobial peptide-DNA complexes controls TLR9 activation (United States)

    Schmidt, Nathan W.; Jin, Fan; Lande, Roberto; Curk, Tine; Xian, Wujing; Lee, Calvin; Frasca, Loredana; Frenkel, Daan; Dobnikar, Jure; Gilliet, Michel; Wong, Gerard C. L.


    Double-stranded DNA (dsDNA) can trigger the production of type I interferon (IFN) in plasmacytoid dendritic cells (pDCs) by binding to endosomal Toll-like receptor-9 (TLR9; refs , , , , ). It is also known that the formation of DNA-antimicrobial peptide complexes can lead to autoimmune diseases via amplification of pDC activation. Here, by combining X-ray scattering, computer simulations, microscopy and measurements of pDC IFN production, we demonstrate that a broad range of antimicrobial peptides and other cationic molecules cause similar effects, and elucidate the criteria for amplification. TLR9 activation depends on both the inter-DNA spacing and the multiplicity of parallel DNA ligands in the self-assembled liquid-crystalline complex. Complexes with a grill-like arrangement of DNA at the optimum spacing can interlock with multiple TLR9 like a zipper, leading to multivalent electrostatic interactions that drastically amplify binding and thereby the immune response. Our results suggest that TLR9 activation and thus TLR9-mediated immune responses can be modulated deterministically.

  16. Milliscale Self-Integration of Megamolecule Biopolymers on a Drying Gas-Aqueous Liquid Crystalline Interface. (United States)

    Okeyoshi, Kosuke; Okajima, Maiko K; Kaneko, Tatsuo


    A drying environment is always a proposition faced by dynamic living organisms using water, which are driven by biopolymer-based micro- and macrostructures. Here, we introduce a drying process for aqueous liquid crystalline (LC) solutions composed of biopolymer with extremely high molecular weight components such as polysaccharides, cytoskeletal proteins, and DNA. On controlling the mobility of the LC microdomain, the solutions showed milliscale self-integration starting from the unstable gas-LC interface during drying. In particular, we first identified giant rod-like microdomains (∼1 μm diameter and more than 20 μm length) of the mega-molecular polysaccharide, sacran, which is remarkably larger than other polysaccharides. These microdomains led to the formation of a single milliscale macrodomain on the interface. In addition, the dried polymer films on a solid substrate also revealed that such integration depends on the size of the microdomain. We envision that this simple drying method will be useful not only for understanding the biopolymer hierarchization at the macroscale level but also for preparation of surfaces with direction controllability, as seen in living organisms, for use in various fields such as diffusion, mechanics, and photonics.

  17. Electrically Conductive Compounds of Polycarbonate, Liquid Crystalline Polymer, and Multiwalled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Penwisa Pisitsak


    Full Text Available A thermotropic liquid crystalline polymer (LCP was blended with polycarbonate (PC and multiwalled carbon nanotube (CNT with the goal of improving electrical conductivity and mechanical properties over PC. The LCP was anticipated to produce fibrillar domains in PC and help improve the mechanical properties. The study was carried out using two grades of LCP—Vectra A950 (VA950 and Vectra V400P (V400P. The compounds contained 20 wt% LCP and 0.5 to 15 wt% CNT. The compounds were prepared by melt-blending in a twin-screw minicompounder and then injection molded using a mini-injection molder. The fibrillar domains of LCP were found only in the case of PC/VA950 blend. However, these fibrils turned into droplets in the presence of CNT. It was found that CNT preferentially remained inside the LCP domains as predicted from the value of spreading coefficient. The electrical conductivity showed the following order with the numbers in parenthesis representing the electrical percolation threshold of the compounds: PC/CNT (1% > PC/VA950P/CNT (1% > PC/V400P/CNT (3%. The storage modulus showed improvements with the addition of CNT and VA950.

  18. Liquid crystalline phase as a probe for crystal engineering of lactose: carrier for pulmonary drug delivery. (United States)

    Patil, Sharvil S; Mahadik, Kakasaheb R; Paradkar, Anant R


    The current work was undertaken to assess suitability of liquid crystalline phase for engineering of lactose crystals and their utility as a carrier in dry powder inhalation formulations. Saturated lactose solution was poured in molten glyceryl monooleate which subsequently transformed into gel. The gel microstructure was analyzed by PPL microscopy and SAXS. Lactose particles recovered from gels after 48 h were analyzed for polymorphism using techniques such as FTIR, XRD, DSC and TGA. Particle size, morphology and aerosolisation properties of prepared lactose were analyzed using Anderson cascade impactor. In situ seeding followed by growth of lactose crystals took place in gels with cubic microstructure as revealed by PPL microscopy and SAXS. Elongated (size ∼ 71 μm) lactose particles with smooth surface containing mixture of α and β-lactose was recovered from gel, however percentage of α-lactose was more as compared to β-lactose. The aerosolisation parameters such as RD, ED, %FPF and % recovery of lactose recovered from gel (LPL) were found to be comparable to Respitose® ML001. Thus LC phase (cubic) can be used for engineering of lactose crystals so as to obtain particles with smooth surface, high elongation ratio and further they can be used as carrier in DPI formulations. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Liquid crystalline nanosheet colloids with controlled particle size obtained by exfoliating single crystal of layered niobate k(4)nb(6)o(17). (United States)

    Miyamoto, Nobuyoshi; Nakato, Teruyuki


    Colloidally dispersed niobate nanosheets with the thickness of 1.8 nm and controlled mean lateral sizes of 0.15-7.8 mum were prepared and their liquid crystallinity was examined. The nanosheet colloids with different lateral sizes were obtained by exfoliation of single crystals of layered niobate K4Nb6O17 and subsequent ultrasonication. Naked-eye and microscope observations of the nanosheet colloids between crossed polarizers revealed liquid crystallinity of the sols characterized by birefringence as functions of the lateral sizes and concentration of the nanosheets. The nanosheet colloids with smaller lateral sizes (0.15-1.9 mum) varied from isotropic to biphasic (isotropic + liquid crystalline), and finally to fully liquid crystalline states as the colloid concentration increased. The phase transition concentrations (from isotropic to biphasic and biphasic to liquid crystalline) decreased with increasing aspect ratio (lateral-to-thickness ratio) of the nanosheets, almost in accordance with the prediction by Onsager theory, indicating that the liquid crystallinity is explained basically by excluded-volume effect between the nanosheets. On the other hand, the colloids with larger lateral sizes (6.2 and 7.8 mum) stably kept liquid crystalline state even at very low concentration (5.1 x 10-6 in volume fraction), which was much lower than that expected from the theory.

  20. Thermoresponsive Membrane Based on Thermotropic Liquid Crystalline Cholesteryl - (L-lacticacidn System: Study of Its Drug Permeability

    Directory of Open Access Journals (Sweden)

    Massoumeh Bagheri


    Full Text Available The rapidly increasing interest in functional materials with reversibly switchable physico- chemical properties has led to significant work on the development of stimuli responsive membranes. Thermotropic liquid crystals with their exceptional properties have potentials for drug-delivery applications. Thermoresponsive liquid-crystal-embedded membranes were investigated for the purpose of developing the drug delivery systems with thermal stimuli response. Drug release occurs at temperatures above the phase transition temperature of thermotropic liquid crystals. Therefore, they can control drug release in response to small temperature changes. In this work, the biocompatible and thermotropic liquid crystalline polymer cholesteryl-(L-lactic acidn ,CLAn (n=30, was synthesized with accurate control of molecular weight via ring opening polymerization method. Polymerization of L-lactide was carried out in the presence of cholesterol as an initiator and catalytic amount of tin (II octoate (Sn(Oct2 at 150°C in 5 h. The number-average degree of polymerization of CLA 30 was obtained from 1H NMR spectroscopy. The phase transition behavior of liquid crystalline CLA30 was established by differential scanning calorimetry and polarizing optical microscopy. The resulting liquid crystalline CLA30 was subsequently utilized to prepare CLA30 -embedded cellulose nitrate membrane by adsorption method. The CLA30-embedded cellulose nitrate membrane was used by an in-vitro drug penetration studies. Acetaminophen was used as a model drug. The permeation study was carried out at different temperatures around glass transition temperature of polymer CLA30 (37, 45 and 40°C, respectively. The results show that the CLA30 -embedded cellulose nitrate membranes exhibit thermo-responsive sensitivity with controlled drug permeation.

  1. Crystalline structure and squeeze-out dissipation of liquid solvation layers observed by small-amplitude dynamic AFM (United States)

    Hofbauer, W.; Ho, R. J.; Hairulnizam, R.; Gosvami, N. N.; O'Shea, S. J.


    Using frequency-modulation atomic force microscopy (FM-AFM) at sub-nanometer vibration amplitudes, we find in the system n -dodecanol/graphite that solvation layers may extend for several nanometers into the bulk liquid. These layers maintain crystalline order which can be imaged using FM-AFM. The energy dissipation of the vibrating tip can peak sharply upon penetration of molecular layers. The tip shape appears critical for this effect.

  2. Lipidic liquid crystalline cubic phases for preparation of ATP-hydrolysing enzyme electrodes. (United States)

    Zatloukalová, Martina; Nazaruk, Ewa; Novák, David; Vacek, Jan; Bilewicz, Renata


    The lipidic liquid-crystalline cubic phase (LCP) is a membrane-mimetic material useful for the stabilization and structural analysis of membrane proteins. Here, we focused on the incorporation of the membrane ATP-hydrolysing sodium/potassium transporter Na(+)/K(+)-ATPase (NKA) into a monoolein-derived LCP. Small-angle X-ray scattering was employed for the determination of the LCP structure, which was of Pn3m symmetry for all the formulations studied. The fully characterized NKA-LCP material was immobilized onto a glassy carbon electrode, forming a highly stable enzyme electrode and a novel sensing platform. A typical NKA voltammetric signature was monitored via the anodic reaction of tyrosine and tryptophan residues. The in situ enzyme activity evaluation was based on the ability of NKA to transform ATP to ADP and free phosphate, the latter reacting with ammonium molybdate to form the ammonium phosphomolybdate complex under acidic conditions. The square-wave voltammetric detection of phosphomolybdate was performed and complemented with spectrophotometric measurement at 710nm. The anodic voltammetric response, corresponding to the catalytic ATP-hydrolysing function of NKA incorporated into the LCP, was monitored at around + 0.2V vs. Ag/AgCl in the presence or absence of ouabain, a specific NKA inhibitor. NKA incorporated into the LCP retained its ATP-hydrolysing activity for 7 days, while the solubilized protein became practically inactive. The novelty of this work is the first incorporation of NKA into a lipidic cubic phase with consequent enzyme functionality and stability evaluation using voltammetric detection. The application of LCPs could also be important in the further development of new membrane protein electrochemical sensors and enzyme electrodes. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Methacrylate Copolymers with Liquid Crystalline Side Chains for Organic Gate Dielectric Applications. (United States)

    Berndt, Andreas; Pospiech, Doris; Jehnichen, Dieter; Häußler, Liane; Voit, Brigitte; Al-Hussein, Mahmoud; Plötner, Matthias; Kumar, Amit; Fischer, Wolf-Joachim


    Polymers for all-organic field-effect transistors are under development to cope with the increasing demand for novel materials for organic electronics. Besides the semiconductor, the dielectric layer determines the efficiency of the final device. Poly(methyl methacrylate) (PMMA) is a frequently used dielectric. In this work, the chemical structure of this material was stepwise altered by incorporation of cross-linkable and/or self-organizing comonomers to improve the chemical stability and the dielectric properties. Different types of cross-linking methods were used to prevent dissolution, swelling or intermixing of the dielectric e.g. during formation processes of top electrodes or semiconducting layers. Self-organizing comonomers were expected to influence the dielectric/semiconductor interface, and moreover, to enhance the chemical resistance of the dielectric. Random copolymers were obtained by free radical and reversible addition-fragmentation chain transfer (RAFT) polymerization. With 6-[4-(4'-cyanophenyl)phenoxy]alkyl side chains having hexyl or octyl spacer, thermotropic liquid crystalline (LC) behavior and nanophase separation into smectic layers was observed, while copolymerization with methyl methacrylate induced molecular disorder. In addition to chemical, thermal and structural properties, electrical characteristics like breakdown field strength (EBD) and relative permittivity (k) were determined. The dielectric films were studied in metal-insulator-metal setups. EBD appeared to be strongly dependent on the type of electrode used and especially the ink formulation. Cross-linking of PMMA yielded an increase in EBD up to 4.0 MV/cm with Ag and 5.7 MV/cm with PSS electrodes because of the increased solvent resistance. The LC side chains reduce the ability for cross-linking resulting in decreased breakdown field strengths.

  4. Magneto-responsive liquid crystalline elastomer nanocomposites as potential candidates for dynamic cell culture substrates

    Energy Technology Data Exchange (ETDEWEB)

    Herrera-Posada, Stephany; Mora-Navarro, Camilo; Ortiz-Bermudez, Patricia; Torres-Lugo, Madeline [Department of Chemical Engineering, Call Box 9000, University of Puerto Rico, Mayagüez PR 00681 (Puerto Rico); McElhinny, Kyle M.; Evans, Paul G. [Department of Materials Science and Engineering, 1509 University Avenue, University of Wisconsin-Madison, WI 53706 (United States); Calcagno, Barbara O. [Department of General Engineering, Call Box 9000, University of Puerto Rico, Mayagüez PR 00681 (Puerto Rico); Acevedo, Aldo, E-mail: [Department of Chemical Engineering, Call Box 9000, University of Puerto Rico, Mayagüez PR 00681 (Puerto Rico)


    Recently, liquid crystalline elastomers (LCEs) have been proposed as active substrates for cell culture due to their potential to attach and orient cells, and impose dynamic mechanical signals through the application of external stimuli. In this report, the preparation of anisotropic and oriented nematic magnetic-sensitized LCEs with iron oxide nanoparticles, and the evaluation of the effect of particle addition at low concentrations on the resultant structural, thermal, thermo-mechanical, and mechanical properties is presented. Phase transformations produced by heating in alternating magnetic fields were investigated in LCEs in contact with air, water, and a common liquid cell culture medium was also evaluated. The inclusion of nanoparticles into the elastomers displaced the nematic-to-isotropic phase transition, without affecting the nematic structure as evidenced by similar values of the order parameter, while reducing the maximum thermomechanical deformations. Remote and reversible deformations of the magnetic LCEs were achieved through the application of alternating magnetic fields, which induces the nematic–isotropic phase transition through nanoparticle heat generation. Formulation parameters can be modified to allow for remote actuation at values closer to the human physiological temperature range and within the range of deformations that can affect the cellular behavior of fibroblasts. Finally, a collagen surface treatment was performed to improve compatibility with NIH-3T3 fibroblast cultures, which enabled the attachment and proliferation of fibroblasts on substrates with and without magnetic particles under quiescent conditions. The LCEs developed in this work, which are able to deform and experience stress changes by remote contact-less magnetic stimulation, may allow for further studies on the effect of substrate morphology changes and dynamic mechanical properties during in vitro cell culture. - Highlights: • Magnetic LCE nanocomposites were

  5. Bulk characterization of topological crystalline insulators: Stability under interactions and relations to symmetry enriched U (1) quantum spin liquids (United States)

    Zou, Liujun


    Topological crystalline insulators (TCIs) are nontrivial quantum phases of matter protected by crystalline (and other) symmetries. They are originally predicted by band theories, so an important question is their stability under interactions. In this paper, by directly studying the physical bulk properties of several band-theory-based nontrivial TCIs that are conceptually interesting and/or experimentally feasible, we show they are stable under interactions. These TCIs include (1) a weak topological insulator, (2) a TCI with a mirror symmetry and its time-reversal symmetric generalizations, (3) a doubled topological insulator with a mirror symmetry, and (4) two TCIs with symmetry-enforced-gapless surfaces. We describe two complementary methods that allow us to determine the properties of the magnetic monopoles obtained by coupling these TCIs to a U (1 ) gauge field. These methods involve studying different types of surface states of these TCIs. Applying these methods to our examples, we find all of them have nontrivial monopoles, which proves their stability under interactions. Furthermore, we discuss two levels of relations between these TCIs and symmetry enriched U (1 ) quantum spin liquids (QSLs). First, these TCIs are directly related to U (1 ) QSLs with crystalline symmetries. Second, there is an interesting correspondence between U (1 ) QSLs with crystalline symmetries and U (1 ) QSLs with internal symmetries. In particular, the TCIs with symmetry-enforced-gapless surfaces are related to the "fractional topological paramagnets" introduced in Zou et al. [arXiv:1710.00743].

  6. Liquid crystalline polymers IX Main chain thermotropic poly (azomethine – ethers containing thiazole moiety linked with polymethylene spacers

    Directory of Open Access Journals (Sweden)


    Full Text Available A new homologous series of thermally stable thermotropic liquid crystalline poly(azomethine-ethers based on thiazole moiety were synthesized by solution polycondensation of 4,4`-diformyl-α,ω-diphenoxyalkanes, I–IV or 4,4`-diformyl-2,2`-dimethoxy-α,ω-diphenoxyalkanes V–VIII with the new bis(2-aminothiazole monomer X. A model compound XI was synthesized from X with benzaldehyde and characterized by elemental and spectral analyses. The inherent viscosities of the resulting polymers were in the range 0.43–1.34 dI/g. All the poly(azomethine-ethers were insoluble in common organic solvents but dissolved completely in concentrated H2SO4 and formic acid. The mesomorphic properties of these polymers were studied as a function of the diphenoxyalkane space length. Their thermotropic liquid crystalline properties were examined by DSC and optical polarizing microscopy and demonstrated that the resulting polymers form nematic mesophases over wide temperature ranges. The thermogravimetric analyses of those polymers were evaluated by TGA and DSC measurements and correlated to their structural units. X-ray analysis showed that polymers having some degree of crystallinity in the region 2θ = 5–60°. In addition, the morphological properties of selected examples were tested by scanning electron microscopy.

  7. Induction of thermotropic bicontinuous cubic phases in liquid-crystalline ammonium and phosphonium salts. (United States)

    Ichikawa, Takahiro; Yoshio, Masafumi; Hamasaki, Atsushi; Taguchi, Satomi; Liu, Feng; Zeng, Xiang-bing; Ungar, Goran; Ohno, Hiroyuki; Kato, Takashi


    Two series of wedge-shaped onium salts, one ammonium and the other phosphonium, having 3,4,5-tris(alkyloxy)benzyl moieties, exhibit thermotropic bicontinuous "gyroid" cubic (Cub(bi)) and hexagonal columnar liquid-crystalline (LC) phases by nanosegregation between ionophilic and ionophobic parts. The alkyl chain lengths on the cationic moieties, anion species, and alkyl chain lengths on the benzyl moieties have crucial effects on their thermotropic phase behavior. For example, triethyl-[3,4,5-tris(dodecyloxy)benzyl]ammonium hexafluorophosphate forms the thermotropic Ia3d Cub(bi) LC phase, whereas an analogous compound with trifluoromethanesulfonate anion shows no LC properties. Synchrotron small-angle diffraction intensities from the Ia3d Cub(bi) LC materials provide electron density maps in the bulk state. The resulting maps show convincingly that the Ia3d Cub(bi) structure is composed of three-dimensionally interconnected ion nanochannel networks surrounded by aliphatic domains. A novel differential mapping technique has been applied successfully. The map of triethyl-[3,4,5-tris(decyloxy)benzyl]ammonium tetrafluoroborate has been subtracted from that of the analogous ammonium salt with hexafluorophosphate anion in the Ia3d Cub(bi) phases. The differential map shows that the counteranions are located in the core of the three-dimensionally interconnected nanochannel networks. Changing from trimethyl- via triethyl- to tripropylammonium cation changes the phase from columnar to Cub(bi) to no mesophase, respectively. This sensitivity to the widened shape for the narrow end of the molecule is explained successfully by the previously proposed semiquantitative geometric model based on the radial distribution of volume in wedge-shaped molecules. The LC onium salts dissolve lithium tetrafluoroborate without losing the Ia3d Cub(bi) LC phase. The Cub(bi) LC materials exhibit efficient ion-transporting behavior as a result of their 3D interconnected ion nanochannel networks

  8. Revealing pathologies in the liquid crystalline structures of the brain by polarimetric studies (Presentation Recording) (United States)

    Bakhshetyan, Karen; Melkonyan, Gurgen G.; Galstian, Tigran V.; Saghatelyan, Armen


    Natural or "self" alignment of molecular complexes in living tissue represents many similarities with liquid crystals (LC), which are anisotropic liquids. The orientational characteristics of those complexes may be related to many important functional parameters and their study may reveal important pathologies. The know-how, accumulated thanks to the study of LC materials, may thus be used to this end. One of the traditionally used methods, to characterize those materials, is the polarized light imaging (PLI) that allows for label-free analysis of anisotropic structures in the brain tissue and can be used, for example, for the analysis of myelinated fiber bundles. In the current work, we first attempted to apply the PLI on the mouse histological brain sections to create a map of anisotropic structures using cross-polarizer transmission light. Then we implemented the PLI for comparative study of histological sections of human postmortem brain samples under normal and pathological conditions, such as Parkinson's disease (PD). Imaging the coronal, sagittal and horizontal sections of mouse brain allowed us to create a false color-coded fiber orientation map under polarized light. In human brain datasets for both control and PD groups we measured the pixel intensities in myelin-rich subregions of internal capsule and normalized these to non-myelinated background signal from putamen and caudate nucleus. Quantification of intensities revealed a statistically significant reduction of fiber intensity of PD compared to control subjects (2.801 +/- 0.303 and 3.724 +/- 0.07 respectively; *p < 0.05). Our study confirms the validity of PLI method for visualizing myelinated axonal fibers. This relatively simple technique can become a promising tool for study of neurodegenerative diseases where labeling-free imaging is an important benefit.

  9. Analysis of liquid crystalline nanoparticles by small angle X-ray diffraction: evaluation of drug and pharmaceutical additives influence on the internal structure. (United States)

    Rossetti, Fábia Cristina; Fantini, Márcia C A; Carollo, Aline Regina H; Tedesco, Antônio Cláudio; Bentley, Maria Vitória Lopes Badra


    The goal of this work was to study the liquid crystalline structure of a nanodispersion delivery system intended to be used in photodynamic therapy after loading with photosensitizers (PSs) and additives such as preservatives and thickening polymers. Polarized light microscopy and light scattering were performed on a standard nanodispersion in order to determine the anisotropy of the liquid crystalline structure and the mean diameter of the nanoparticles, respectively. Small angle X-ray diffraction (SAXRD) was used to verify the influence of drug loading and additives on the liquid crystalline structure of the nanodispersions. The samples, before and after the addition of PSs and additives, were stable over 90 days, as verified by dynamic light scattering. SAXRD revealed that despite the alteration observed in some of the samples analyzed in the presence of photosensitizing drugs and additives, the hexagonal phase still remained in the crystalline phase. Copyright © 2011 Wiley-Liss, Inc. and the American Pharmacists Association

  10. Tilted Orientation of Photochromic Dyes with Guest-Host Effect of Liquid Crystalline Polymer Matrix for Electrical UV Sensing

    Directory of Open Access Journals (Sweden)

    Amid Ranjkesh


    Full Text Available We propose a highly oriented photochromic dye film for an ultraviolet (UV-sensing layer, where spirooxazine (SO derivatives are aligned with the liquid crystalline UV-curable reactive mesogens (RM using a guest-host effect. For effective electrical UV sensing with a simple metal-insulator-metal structure, our results show that the UV-induced switchable dipole moment amount of the SO derivatives is high; however, their tilting orientation should be controlled. Compared to the dielectric layer with the nearly planar SO dye orientation, the photochromic dielectric layer with the moderately tilted dye orientation shows more than seven times higher the UV-induced capacitance variation.

  11. Preparation and Characterization of Liquid Crystalline Polyurethane/Al2O3/Epoxy Resin Composites for Electronic Packaging

    Directory of Open Access Journals (Sweden)

    Shaorong Lu


    Full Text Available Liquid crystalline polyurethane (LCPU/Al2O3/epoxy resin composites were prepared by using LCPU as modifier. The mechanical properties, thermal stability, and electrical properties of the LCPU/Al2O3/epoxy resin composites were investigated systematically. The thermal oxidation analysis indicated that LCPU/Al2O3/epoxy resin composites can sustain higher thermal decomposition temperature. Meanwhile, coefficient of thermal expansion (CTE was also found to decrease with addition of LCPU and nano-Al2O3.

  12. Synthesis of Isothianaphthene (ITN and 3,4-Ethylenedioxy-Thiophene (EDOT-Based Low-Bandgap Liquid Crystalline Conjugated Polymers

    Directory of Open Access Journals (Sweden)

    Hiromasa Goto


    Full Text Available Copolymers, consisting of isothianaphthene and phenylene derivatives with liquid crystal groups, were synthesized via Migita-Kosugi-Stille polycondensation reaction. IR absorption, UV-vis optical absorption, and PL spectroscopy measurements were carried out. Thermotropic liquid crystallinity of the polymers with bandgap of ~2.5 eV was confirmed.

  13. Rheology of the lamellar liquid-crystalline phase in polyethoxylated alcohol/water/heptane systems.

    Directory of Open Access Journals (Sweden)

    Gallegos, C.


    Full Text Available Linear viscoelastic tests as well as transient and steady flow experiments were carried out on lamellar liquid crystalline samples of poly (oxyethylene alcohol/water/heptane systems. The effect of surfactant and heptane concentrations on the rheological properties of the lamellar mesophase was investigated. The mechanical spectrum inside the linear viscoelastic regime shows, in all cases, a well-developed plateau region in the whole frequency range studied. The values of the dynamic functions were higher for intermediate surfactant or heptane concentrations indicative of a major development of the elastic network in the midrange of existence of the lamellar phase. Transient and steady flow experiments point out a shear-induced evolution of the lamellar microstructure. Different power law regions with different values of the flow index were detected in the viscosity versus shear rate plots. These shear-induced structural modifications were confirmed by using polarizing microscopy in an optical shearing cell. Structural modifications appear to be highly influenced by shear rate. In general, applying relatively high constant shear rates, the alignment of the bilayers followed by the appearance of the “oily streaks” structure was observed. Appearance of shear-induced vesicles occurs at high heptane content, as indicates the texture of close-packed monodisperse spherulites detected by polarizing microscopy.n este trabajo se han estudiado las propiedades reológicas de una fase líquido-cristalina laminar contenida en un sistema alcohol polietoxilado/agua/heptano, mediante ensayos viscoelásticos lineales, estacionarios y transitorios. El efecto de distintas variables como la composición de tensioactivo y heptano sobre dichas propiedades reológicas ha sido analizado. El espectro mecánico obtenido de la fase laminar muestra en todos los casos una región “plateau” en el intervalo de frecuencias estudiado así como mayores valores

  14. Presence of retained crystalline seed necessary for bicrystal-liquid-bicrystal phase transformation (United States)

    Vijay Reddy, K.; Meraj, Md.; Pal, Snehanshu


    Regaining of the original bicrystal structure during solidification after melting is found to be possible only if a fraction of crystalline seed is retained in the melt as per this molecular dynamics study. The effect of cooling rate on retaining the crystalline seed is also investigated. The bicrystal specimen is heated up to 1850 K with a constant heating rate of 3.5 K ps-1 and instantly cooled with different cooling rates i.e. 1 K ps-1, 5 K ps-1, 10 K ps-1, 15 K ps-1 and 20 K ps-1. It has been observed through total energy analysis that specimen cooled with 1 K ps-1 cooling rate dissipates the energy throughout the specimen causing randomization of atoms resulting into disappearance of the crystalline seed and formation of nanocrystalline structure. Whereas comparatively higher cooling rates does not allow complete dissipation of energy and retain the crystalline seed thus transform into bicrystal. It has been found through Voronoi polyhedra analysis that during slower cooling rate, icosahedral clusters are formed which play a vital role in formation of nanocrystalline structure.

  15. Effect of organoclay on the orientation and thermal properties of liquid-crystalline polymers

    CSIR Research Space (South Africa)

    Bandyopadhyay, J


    Full Text Available in the pure LCP; in the nanocomposites, the polymer chains tended to orient in the direction of the dispersed clay layers. According to the DSC results, during first heating, the first melting peak represents the crystalline to nematic transition and, after...

  16. Photoorientation in thin aligned layers of side-group liquid crystalline copolysiloxane doped with azobenzene and stilbene derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Wolarz, E.; Fischer, Th.; Stumpe, J


    Optically anisotropic films of side-group liquid crystalline copolysiloxane doped with photochromic azobenzene and stilbene derivatives were prepared by using standard liquid crystal cells of 4 {mu}m in thickness. The films were irradiated with high power density laser light with the electric field vector creating an angle equal to 45 deg. with the initial optical axis of the samples. As a result of irradiation, the photoorientation of the photochromic molecules, and the cooperative reorientation of the copolysiloxane side groups occurred. In the case of the copolymer layers containing azobenzene, the optical axis was turned by an angle of 45 deg. during sufficiently long irradiation. The angle of reorientation and the degree of anisotropy were determined for the irradiated areas of the samples.

  17. Design and Characterization of a Novel p1025 Peptide-Loaded Liquid Crystalline System for the Treatment of Dental Caries

    Directory of Open Access Journals (Sweden)

    Giovana Maria Fioramonti Calixto


    Full Text Available Dental caries, mainly caused by the adhesion of Streptococcus mutans to pellicle-coated tooth surfaces, is an important public health problem worldwide. A synthetic peptide (p1025 corresponding to residues 1025–1044 of the adhesin can inhibit this binding. Peptides are particularly susceptible to the biological environment; therefore, a p1025 peptide-loaded liquid crystalline system (LCS consisting of tea tree oil as the oil phase, polyoxypropylene-(5-polyoxyethylene-(20-cetyl alcohol as the surfactant, and water or 0.5% polycarbophil polymer dispersions as the aqueous phase was employed as a drug delivery platform. This system exhibited anticaries and bioadhesive properties and provided a protective environment to p1025 at the site of action, thereby modulating its action, prolonging its contact with the teeth, and decreasing the frequency of administration. LCSs were characterized by polarized light microscopy (PLM, small-angle X-ray scattering (SAXS, and rheological, texture, and bioadhesive tests. PLM and SAXS revealed the presence of hexagonal liquid crystalline phases and microemulsions. Rheological analyses demonstrated that the addition of polymer dispersions favored characteristics such as shear thinning and thixotropy, hence improving buccal application. Bioadhesion tests showed that polymer dispersions contributed to the adhesion onto the teeth. Taken together, LCS could provide a novel pharmaceutical nanotechnology platform for dental caries treatment.

  18. Thermal properties and crystallite morphology of nylon 66 modified with a novel biphenyl aromatic liquid crystalline epoxy resin. (United States)

    Cai, Zhiqi; Mei, Shuang; Lu, Yuan; He, Yuanqi; Pi, Pihui; Cheng, Jiang; Qian, Yu; Wen, Xiufang


    In order to improve the thermal properties of important engineering plastics, a novel kind of liquid crystalline epoxy resin (LCER), 3,3',5,5' -Tetramethylbiphenyl-4,4' -diyl bis(4-(oxiran-2-ylmethoxy)benzoate) (M1) was introduced to blend with nylon 66 (M2) at high temperature. The effects of M1 on chemical modification and crystallite morphology of M2 were investigated by rheometry, thermo gravimetric analysis (TGA), dynamic differential scanning calorimetry (DSC) and polarized optical microscopy (POM). TGA results showed that the initial decomposition temperature of M2 increased by about 8 °C by adding 7% wt M1, indicating the improvement of thermal stability. DSC results illustrated that the melting point of composites decreased by 12 °C compared to M2 as the content of M1 increased, showing the improvement of processing property. POM measurements confirmed that dimension of nylon-66 spherulites and crystallization region decreased because of the addition of liquid crystalline epoxy M1.

  19. Magnetic Field Alignment of PS-P4VP: a Non-Liquid Crystalline Coil-Coil Block Copolymer (United States)

    Rokhlenko, Yekaterina; Zhang, Kai; Larson, Steven; Gopalan, Padma; O'Hern, Corey; Osuji, Chinedum


    Magnetic fields provide the ability to control alignment of self-assembled soft materials such as block copolymers. Most prior work in this area has relied on the presence of ordered assemblies of anisotropic liquid crystalline species to ensure sufficient magnetic anisotropy to drive alignment. Recent experiments with poly(styrene-b-4-vinylpyridine), a non-liquid crystalline BCP, however, show field-induced alignment of a lamellar microstructure during cooling across the order-disorder transition. Using in situ x-ray scattering, we examine the roles of field strength and cooling rate on the alignment response of this low MW coil-coil BCP. Alignment is first observed at field strengths as low as 1 Tesla and improves markedly with both increasing field strength and slower cooling. We present a geometric argument to illustrate the origin of a finite, non-trivial magnetic susceptibility anisotropy for highly stretched surface-tethered polymer chains and corroborate this using coarse-grained molecular dynamics simulations. We rationalize the magnetic field response of the system in terms of the mobility afforded by the absence of entanglements, the intrinsic anisotropy resulting from the stretched polymer chains and sterically constrained conjugated rings, and the large grain size in these low molecular weight materials.

  20. Design and Characterization of a Novel p1025 Peptide-Loaded Liquid Crystalline System for the Treatment of Dental Caries. (United States)

    Calixto, Giovana Maria Fioramonti; Garcia, Matheus Henrique; Cilli, Eduardo Maffud; Chiavacci, Leila Aparecida; Chorilli, Marlus


    Dental caries, mainly caused by the adhesion of Streptococcus mutans to pellicle-coated tooth surfaces, is an important public health problem worldwide. A synthetic peptide (p1025) corresponding to residues 1025-1044 of the adhesin can inhibit this binding. Peptides are particularly susceptible to the biological environment; therefore, a p1025 peptide-loaded liquid crystalline system (LCS) consisting of tea tree oil as the oil phase, polyoxypropylene-(5)-polyoxyethylene-(20)-cetyl alcohol as the surfactant, and water or 0.5% polycarbophil polymer dispersions as the aqueous phase was employed as a drug delivery platform. This system exhibited anticaries and bioadhesive properties and provided a protective environment to p1025 at the site of action, thereby modulating its action, prolonging its contact with the teeth, and decreasing the frequency of administration. LCSs were characterized by polarized light microscopy (PLM), small-angle X-ray scattering (SAXS), and rheological, texture, and bioadhesive tests. PLM and SAXS revealed the presence of hexagonal liquid crystalline phases and microemulsions. Rheological analyses demonstrated that the addition of polymer dispersions favored characteristics such as shear thinning and thixotropy, hence improving buccal application. Bioadhesion tests showed that polymer dispersions contributed to the adhesion onto the teeth. Taken together, LCS could provide a novel pharmaceutical nanotechnology platform for dental caries treatment.

  1. Long-term Denitrification Processes and Kinetics in a Crystalline Aquifer subject to Pumping from 1991 (United States)

    Roques, Clement; Aquilina, Luc; Vergnaud-Ayraud, Virginie; Boisson, Alexandre; Labasque, Thierry; Longuevergne, Laurent; Ben Maamar, Sarah; Dufresne, Alexis; Bour, Olivier


    critical role in sustaining the Nitrate reduction processes. Both nitrate reduction and Sulfate production as well as Fluor release ratios support the hypothesis that biotite play a major role of electron donor in this context. Field-scale pumping experiments in two other crystalline aquifers from Britany also showed similar denitrification reactions without sulfate production in a stoichiometric ratio to nitrate consumption. Metagenomic analysis of these three aquifers showed a highly structured system. Microbial communities are dominated by potential denitrifiers in the upper weathered compartment while the deeper fractured system shows communities dominated by Gallionellaceae group, both groups being potentially involved in the denitrification processes.

  2. NATO Advanced Research Workshop on Computational Methods for Polymers and Liquid Crystalline Polymers

    CERN Document Server

    Pasini, Paolo; Žumer, Slobodan; Computer Simulations of Liquid Crystals and Polymers


    Liquid crystals, polymers and polymer liquid crystals are soft condensed matter systems of major technological and scientific interest. An understanding of the macroscopic properties of these complex systems and of their many and interesting peculiarities at the molecular level can nowadays only be attained using computer simulations and statistical mechanical theories. Both in the Liquid Crystal and Polymer fields a considerable amount of simulation work has been done in the last few years with various classes of models at different special resolutions, ranging from atomistic to molecular and coarse-grained lattice models. Each of the two fields has developed its own set of tools and specialized procedures and the book aims to provide a state of the art review of the computer simulation studies of polymers and liquid crystals. This is of great importance in view of a potential cross-fertilization between these connected areas which is particularly apparent for a number of experimental systems like, e.g. poly...

  3. Particles of liquid-crystalline dispersions formed by (nucleic acid-rare earth element) complexes as a potential platform for neutron capture therapy. (United States)

    Yevdokimov, Yury M; Salyanov, Victor I; Kondrashina, Olga V; Borshevsky, Valentin I; Semenov, Sergey V; Gasanov, Achmedali A; Reshetov, Igor V; Kuznetsov, Vjacheslav D; Nikiforov, Vladimir N; Akulinichev, Sergey V; Mordovskoi, Mikhail V; Potashev, Stanislav I; Skorkin, Vladimir M


    Microscopic size particles of the cholesteric double-stranded DNA (RNA) liquid-crystalline dispersions, containing the ions of the rare earth elements in their content, have been obtained for the first time. The properties of these particles differ from those of classical DNA cholesterics noticeably. The local concentration of the rare earth elements in a particle reaches 200 mg/ml. The particles of the liquid-crystalline dispersion of the (DNA-gadolinium) complex maintain the properties for a long time. The combination of the microscopic size of particles, high concentration of gadolinium in particles and their stability opens a way to practical application of this new biomaterial.

  4. Comparison of drug release from liquid crystalline monoolein dispersions and solid lipid nanoparticles using a flow cytometric technique

    Directory of Open Access Journals (Sweden)

    Mohamed Z. Dawoud


    Full Text Available Colloidal lipid particles such as solid lipid nanoparticles and liquid crystalline nanoparticles have great opportunities as drug carriers especially for lipophilic drugs intended for intravenous administration. In order to evaluate drug release from these nanoparticles and determine their behavior after administration, emulsion droplets were used as a lipophilic compartment to which the transfer of a model drug was measured. The detection of the model drug transferred from monoolein cubic particles and trimyristin solid lipid nanoparticles into emulsion droplets was performed using a flow cytometric technique. A higher rate and amount of porphyrin transfer from the solid lipid nanoparticles compared to the monoolein cubic particles was observed. This difference might be attributed to the formation of a highly ordered particle which leads to the expulsion of drug to the surface of the crystalline particle. Furthermore, the sponge-like structure of the monoolein cubic particles decreases the rate and amount of drug transferred. In conclusion, the flow cytometric technique is a suitable technique to study drug transfer from these carriers to large lipophilic acceptors. Monoolein cubic particles with their unique structure can be used successfully as a drug carrier with slow drug release compared with trimyristin nanoparticles.

  5. Study of order and dynamics in liquid crystalline materials by carbon-13 and deuterium NMR spectroscopy (United States)

    Xu, Jiadi

    This dissertation investigates the phase structures, molecular structures and diffusion motions in some recently discovered liquid crystals using 1D and 2D carbon-13 and deuterium NMR spectroscopy. Two classes of liquid crystals are involved: chiral rod-like liquid crystals and banana mesogens. Our investigations of these new materials were divided into five main sections. The ordering and structures of banana liquid crystals and chiral rod-like mesogens were extracted from solid-state 13C NMR experiments including Separated-Local-Field study based on Lee-Goldberg Cross-Polarization (LGCP-SLF) and temperature dependent chemical shifts. The principal values of CSA tensor were measured using Separation of Undistorted CSA Powder patterns by Effortless Recoupling (SUPER) experiment. Some ID and 2D pulse experiments were performed for the assignment of carbon peaks, such as Cross-Polarization Polarization-Inversion (CPPI), HECTOR and so on. The soliton-like distortion of the helicoidal structure in the chiral smectic C phase (SmC*) of 8BEF5 liquid crystal was observed by the angular dependent DNMR patterns, and quantitatively interpreted based on Landau theory. The distortion was induced by the NMR magnetic field. The phase structure and interlayer diffusion in anticlinic Sm C* phases (Sm C*A , Sm C*Fi1 and Sm C*Fi2 ) of 10B1M7 liquid crystal were measured using angular dependent DNMR lineshapes and echo intensities. This work represents the first study of ferrielectric smectic phases by means of NMR. Measurements of the interlayer diffusion in synclinic and anticlinic SmC* phases (SmC*, Sm C*Fi1 and Sm C*Fi2 ) of 10B1M7 were carried out using 2H NMR exchange experiments. The phase structures of anticlinic SmC* phases were also determined using the same technique. A 'deformed clock model' was found to be appropriate for these phases. Molecular structures and dynamics were investigated in an exotic B 2 phase of a banana liquid crystal Pbis11BB by means of CP-MAS 13C NMR

  6. Aerogels with 3D ordered nanofiber skeletons of liquid-crystalline nanocellulose derivatives as tough and transparent insulators. (United States)

    Kobayashi, Yuri; Saito, Tsuguyuki; Isogai, Akira


    Aerogels of high porosity and with a large internal surface area exhibit outstanding performances as thermal, acoustic, or electrical insulators. However, most aerogels are mechanically brittle and optically opaque, and the structural and physical properties of aerogels strongly depend on their densities. The unfavorable characteristics of aerogels are intrinsic to their skeletal structures consisting of randomly interconnected spherical nanoparticles. A structurally new type of aerogel with a three-dimensionally ordered nanofiber skeleton of liquid-crystalline nanocellulose (LC-NCell) is now reported. This LC-NCell material is composed of mechanically strong, surface-carboxylated cellulose nanofibers dispersed in a nematic LC order. The LC-NCell aerogels are transparent and combine mechanical toughness and good insulation properties. These properties of the LC-NCell aerogels could also be readily controlled. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Enhanced thermal and mechanical properties of epoxy composites by mixing thermotropic liquid crystalline epoxy grafted graphene oxide

    Directory of Open Access Journals (Sweden)

    B. Qi


    Full Text Available Graphene oxide (GO sheets were chemically grafted with thermotropic liquid crystalline epoxy (TLCP. Then we fabricated composites using TLCP-g-GO as reinforcing filler. The mechanical properties and thermal properties of composites were systematically investigated. It is found that the thermal and mechanical properties of the composites are enhanced effectively by the addition of fillers. For instance, the composites containing 1.0 wt% of TLCP-g-GO present impact strength of 51.43 kJ/m2, the tensile strength of composites increase from 55.43 to 80.85 MPa, the flexural modulus of the composites increase by more than 48%. Furthermore, the incorporation of fillers is effective to improve the glass transition temperature and thermal stability of the composites. Therefore, the presence of the TLCP-g-GO in the epoxy matrix could make epoxy not only stronger but also tougher.

  8. Design criteria for ionic liquid crystalline phases of phosphonium salts with three equivalent long n-alkyl chains. (United States)

    Ma, Kefeng; Lee, Kwang-Ming; Minkova, Liliya; Weiss, Richard G


    The factors influencing the formation, organizations, and temperature ranges of the smectic phases of a structurally diverse family of phosphonium salts have been examined. The salts consist of one short group and three long n-alkyl chains attached to a positively charged phosphorus atom and either a free or covalently attached counterion, the latter resulting in zwitterionic salts. Of the 61 salts investigated, of which 37 have not been synthesized previously, most pack in lamellae within their solid phases. Single-crystal X-ray structures of two of amidomethyl-tri-n-tetradecylphosphonium bromide (1P14CONH(2)Br) and carboxymethyl-tri-n-tetradecylphosphonium bromide (1P14CO(2)HBr) have been solved. In each, the constituent molecules are packed in stacks of bilayers in which the directors of molecules on opposite sides of the ionic planes (where the phosphonium cationic centers and anions are located) that separate the layers are antiparallel. In each molecule, two of the long n-alkyl chains are paired while the third is antiparallel to the other two and paired with an n-alkyl chain of a molecule in a neighboring bilayer. The tri-n-alkylmethylphosphonium salts (1PnX) with small anions X (where n = 6-18 is the number of carbon atoms in the three long chain and 1 is the methyl group) do not form liquid-crystalline phases as a consequence of strong alternating intra- and intermolecular P(+)-X(-) interactions within the ionic planes that separate the bilayers of long chains. Thermotropic and enantiotropic liquid-crystalline phase formation of 1PnX salts is favored by larger anions and longer n-alkyl chains, which reduce order within ionic planes while promoting order within the lipophilic layers. We conjecture that covalent attachment of a hydroxymethylene, carboxy, or amido functional group Y to the alpha-methyl group of a 1PnX salt (resulting in mPnYX salts, where m is the number of methylene units separating the phosphorus atom from the Y group on the short chain

  9. Nanostructure of liquid crystalline matrix determines in vitro sustained release and in vivo oral absorption kinetics for hydrophilic model drugs. (United States)

    Lee, Kathy W Y; Nguyen, Tri-Hung; Hanley, Tracey; Boyd, Ben J


    Nanostructured lipid-based liquid crystalline systems have been proposed as sustained oral drug delivery systems, but the interplay between their intrinsic release rates, susceptibility to digestive processes, and the manner in which these effects impact on their application in vivo, are not well understood. In this study, two different bicontinuous cubic phases, prepared from glyceryl monooleate and phytantriol, and a reversed hexagonal phase formed by addition of a small amount of vitamin E to phytantriol (Q(II GMO), Q(II PHYT) and H(II PHYT+VitEA), respectively) were prepared. The release kinetics for a number of model hydrophilic drugs with increasing molecular weights (glucose, Allura Red and FITC-dextrans) was determined in in vitro release experiments. Diffusion-controlled release was observed in all cases as anticipated from previous studies with liquid crystalline systems, and it was discovered that the release rates of each drug decreased as the matrix was changed from Q(II GMO) to Q(II PHYT) to H(II PHYT+VitEA). Formulations containing (14)C-glucose, utilized as a rapidly absorbed marker of drug release, were then orally administered to rats to determine the relative in vivo absorption rates from the different formulations. The results showed a trend by which the rate of absorption of (14)C-glucose followed that observed in the corresponding in vitro release studies, providing the first indication that the nanostructure of these materials may provide the ability to tailor the absorption kinetics of hydrophilic drugs in vivo, and hence form the basis of a new drug delivery system.

  10. Designing solution-processable air-stable liquid crystalline crosslinkable semiconductors

    DEFF Research Database (Denmark)

    McCulloch, I.; Bailey, C.; Genevicius, K.


    will typically be of lower performance than those using the present state of the art single crystal or polysilicon transistors, but comparable to amorphous silicon. A range of prototypes are under development, including rollable electrophoretic displays, active matrix liquid crystal (LC) displays, flexible...

  11. The mutual influence of a liquid crystalline medium and chiral dopants of 1R,4R- n-mentane-3-one 2-arylidene derivatives dissolved in it (United States)

    El'Ts, E. E.; Komolkin, A. V.; Kutulya, L. A.; Pivnenko, N. S.


    Molecular dynamics computer simulation and quantum chemistry methods were used to study the influence of nematic liquid crystalline 4- n-pentyl-4'-cyanobiphenyl on the conformations of chiral dopant molecules of 1R,4R- n-menthane-3-one 2-arylidene derivatives and the influence of these chiral dopants on the conformation of the liquid crystal. The simulation results are compared with the available experimental data.

  12. The role of molecular packing on carrier transport in liquid crystalline dyes


    Tchamba Yimga, Nadine


    Organic semiconductors offer the possibility to develop light weight, flexible and cost-effective applications for energy production and optoelectronic industry. However, the difficulty in controlling crystal growth and thin film morphology remain the main hindrances in achieving good electrical transport, which is essential for efficient device performance. In the family of organic semiconductors, liquid crystal (LC) semiconductors offer a unique flexibility in controlling thin film morpholo...

  13. Two-mode Ginzburg-Landau theory of crystalline anisotropy for fcc-liquid interfaces (United States)

    Wu, Kuo-An; Lin, Shang-Chun; Karma, Alain


    We develop a Ginzburg-Landau (GL) theory for fcc crystal-melt systems at equilibrium by employing two sets of order parameters that correspond to amplitudes of density waves of principal reciprocal lattice vectors and amplitudes of density waves of a second set of reciprocal lattice vectors. The choice of the second set of reciprocal lattice vectors is constrained by the condition that this set must form closed triangles with the principal reciprocal lattice vectors in reciprocal space to make the fcc-liquid transition first order. The capillary anisotropy of fcc-liquid interfaces is investigated by GL theory with amplitudes of and density waves. Furthermore, we explore the dependence of the anisotropy of the excess free energy of the solid-liquid interface on density waves of higher-order reciprocal lattice vectors such as by extending the two-mode GL theory with an additional mode. The anisotropy calculated using GL theory with input parameters from molecular dynamics (MD) simulations for fcc Ni is compared to that measured in MD simulations.

  14. Solid-liquid equilibria of crystalline and semi-crystalline monodisperse polymers, taking into account the molecular architecture by application of the lattice cluster theory (United States)

    Fischlschweiger, Michael; Enders, Sabine


    In this work, an old theory for the melting of linear, semi-crystalline polymers, developed by Flory in 1949, is rediscovered and extended to branched polymers. The extension is realised by the incorporation of the lattice cluster theory, which is able to model polymers with an arbitrary architecture. The final working equation describing the melting of a branched semi-crystalline polymer can be solved for the melting temperature analytically. This new equation permits the theoretical investigation of different impact factors on the melting temperature in the case of branched semi-crystalline polymer, for instance the influence of molecular weight on the structural variables that describe the crystalline state. It could be shown that the extension leads to a better description of experimental data for the melting of high-density polyethylene taken from the literature than the original equation of linear semi-crystalline polymers. However, the comparison with experimental data makes it clear that the incorporation of polydispersity in the theoretical framework is needed.

  15. Alternating side-chain liquid-crystalline copolymers with polar moieties in the backbone = Alternerende zijketen vloeibaar-kristallijne copolymeren met polaire groepen in de hoofdketen

    NARCIS (Netherlands)

    Nieuwhof, R.P.


    Side-chain liquid-crystalline polymers (SCLCPs) obtained via the alternating copolymeri-zation of maleic anhydride (MA) and mesogenic 1-alkenes are an interesting class of polymers that may show good adhesion towards metal surfaces and form ordered layered structures. If these polymers

  16. Side-chain liquid-crystalline poly(ketone)s : effect of spacer length, mesogen type and mesogen density on mesomorphic behavior

    NARCIS (Netherlands)

    Nieuwhof, R.P.; Marcelis, A.T.M.; Sudhölter, E.J.R.; Wursche, R.; Rieger, B.


    Novel side-chain liquid-crystalline copolymers (SCLCPs) were synthesized via the Pd(II) catalyzed alternating copolymerization of mesogenic 1-alkenes and carbon monoxide. For methoxybiphenyl mesogens, these copolymers exhibited highly ordered smectic E mesophases and high glass transition

  17. The Effect of 4-Octyldecyloxybenzoic Acid on Liquid-Crystalline Polyurethane Composites with Triple-Shape Memory and Self-Healing Properties

    Directory of Open Access Journals (Sweden)

    Jianfeng Ban


    Full Text Available To better understand shape memory materials and self-healing materials, a new series of liquid-crystalline shape memory polyurethane (LC-SMPU composites, named SMPU-OOBAm, were successfully prepared by incorporating 4-octyldecyloxybenzoic acid (OOBA into the PEG-based SMPU. The effect of OOBA on the structure, morphology, and properties of the material has been carefully investigated. The results demonstrate that SMPU-OOBAm has liquid crystalline properties, triple-shape memory properties, and self-healing properties. The incorporated OOBA promotes the crystallizability of both soft and hard segments of SMPU, and the crystallization rate of the hard segment of SMPU decreases when the OOBA-content increases. Additionally, the SMPU-OOBAm forms a two-phase separated structure (SMPU phase and OOBA phase, and it shows two-step modulus changes upon heating. Therefore, the SMPU-OOBAm exhibits triple-shape memory behavior, and the shape recovery ratio decreases with an increase in the OOBA content. Finally, SMPU-OOBAm exhibits self-healing properties. The new mechanism can be ascribed to the heating-induced “bleeding” of OOBA in the liquid crystalline state and the subsequent re-crystallization upon cooling. This successful combination of liquid crystalline properties, triple-shape memory properties, and self-healing properties make the SMPU-OOBAm composites ideal for many promising applications in smart optical devices, smart electronic devices, and smart sensors.

  18. Improving Stiffness, Strength, and Toughness of Poly(omega-pentadecalactone) Fibers through in Situ Reinforcement with a Vanillic Acid-Based Thermotropic Liquid Crystalline Polyester

    NARCIS (Netherlands)

    Wilsens, Carolus H. R. M.; Pepels, Mark P. F.; Spoelstra, Anne B.; Portale, Giuseppe; Auhl, Dietmar; Deshmukh, Yogesh S.; Harings, Jules A. W.


    We report on the morphology and performance of melt drawn poly(omega-pentadecalactone) (PPDL) fibers reinforced with a vanillic acid-based thermotropic liquid crystalline polyester (LCP). The in situ reinforced PPDL/LCP fibers developed in this work are considered to be renewable in nature, given

  19. Nonuniform liquid-crystalline phases of parallel hard rod-shaped particles: From ellipsoids to cylinders (United States)

    Martínez-Ratón, Y.; Velasco, E.


    In this article we consider systems of parallel hard superellipsoids, which can be viewed as a possible interpolation between ellipsoids of revolution and cylinders. Superellipsoids are characterized by an aspect ratio and an exponent α (shape parameter) which takes care of the geometry, with α=1 corresponding to ellipsoids of revolution, while α=∞ is the limit of cylinders. It is well known that, while hard parallel cylinders exhibit nematic, smectic, and solid phases, hard parallel ellipsoids do not stabilize the smectic phase, the nematic phase transforming directly into a solid as density is increased. We use computer simulation to find evidence that for α>=αc, where αc is a critical value which the simulations estimate to be approximately 1.2-1.3, the smectic phase is stabilized. This is surprisingly close to the ellipsoidal case. In addition, we use a density-functional approach, based on the Parsons-Lee approximation, to describe smectic and columnar orderings. In combination with a free-volume theory for the crystalline phase, a theoretical phase diagram is predicted. While some qualitative features, such as the enhancement of smectic stability for increasing α and the probable absence of a stable columnar phase, are correct, the precise location of coexistence densities is quantitatively incorrect.

  20. Stabilization of Bend Alignment Using Optical Polymerization of UV Curable Liquid Crystalline Monomers (United States)

    Asakawa, Youichi; Yokota, Kouji; Nanaumi, Makoto; Takatuka, Naoki; Takahashi, Taiju; Saito, Susumu


    Director profiles and electrooptical properties in polymer-stabilized π cells used in optically compensated bend (OCB) liquid crystal displays (LCDs) are theoretically investigated by introducing an additional term which expresses the effect of polymer stabilization on the free energy density. The conditions required to stabilize the bend alignment definitively have been theoretically clarified and experimentally confirmed. As a result, the bend alignment is successfully stabilized even if the twist state is more stable than the bend state before the application of polymer-stabilization treatment.

  1. Formation of Photo-Responsive Liquid Crystalline Emulsion by Using Microfluidics Device

    Directory of Open Access Journals (Sweden)

    Yoshiharu Dogishi


    Full Text Available Photo-responsive double emulsions made of liquid crystal (LC were prepared by a microfluidic device, and the light-induced processes were studied. The phase transition was induced from the center of the topological defect for an emulsion made of (N-(4-methoxybenzylidene-4-butylaniline (MBBA, and strange texture change was observed for an emulsion made of 4-cyano-4′-pentylbiphenyl (5CB doped with azobenzene. The results suggest that there are defect-involved processes in the phase change of LC double emulsions.

  2. Ginzburg-Landau theory of crystalline anisotropy for bcc-liquid interfaces (United States)

    Wu, Kuo-An; Karma, Alain; Hoyt, Jeffrey J.; Asta, Mark


    The weak anisotropy of the interfacial free energy γ is a crucial parameter influencing dendritic crystal growth morphologies in systems with atomically rough solid-liquid interfaces. The physical origin and quantitative prediction of this anisotropy are investigated for body-centered-cubic (bcc) forming systems using a Ginzburg-Landau theory where the order parameters are the amplitudes of density waves corresponding to principal reciprocal lattice vectors. We find that this theory predicts the correct sign γ100 > γ110 and magnitude ( γ100 - γ110 ) / ( γ100 + γ110 ) ≈1% of this anisotropy in good agreement with the results of molecular dynamics (MD) simulations for Fe. The results show that the directional dependence of the rate of spatial decay of solid density waves into the liquid, imposed by the crystal structure, is a main determinant of anisotropy. This directional dependence is validated by MD computations of density wave profiles for different reciprocal lattice vectors for {110} crystal faces. Our results are contrasted with the prediction of the reverse ordering γ100 < γ110 from an earlier formulation of Ginzburg-Landau theory [Shih et al., Phys. Rev. A 35, 2611 (1987)].

  3. Design of polarization-dependent, flexural-torsional deformation in photo responsive liquid crystalline polymer networks. (United States)

    Smith, Matthew L; Lee, Kyung Min; White, Timothy J; Vaia, Richard A


    Light responsive materials that exhibit wirelessly actuated, multidimensional deformation are excellent candidates for programmable matter applications such as morphing structures or soft robotics. A central challenge to designing adaptive structures from these materials is the ability accurately predict three dimensional deformations. Previous modeling efforts have focused almost exclusively on pure bending. Herein we examine key material parameters affecting light driven flexural-torsional response in azobenzene functionalized liquid crystal polymer networks. We show that a great deal of control can be obtained by specifying material alignment and actuating the material with polarized light. Insight gained from the theoretical framework here lays the foundation for more extensive modeling efforts to combine polarization controlled flexural-torsional deformations with complex geometry, boundary conditions, and loading conditions.

  4. Unidirectional rotary motion in a liquid crystalline environment: Color tuning by a molecular motor (United States)

    van Delden, Richard A.; Koumura, Nagatoshi; Harada, Noboyuki; Feringa, Ben L.


    Life could not exist without motion induced by a variety of molecular motors. The construction of artificial motors by chemical synthesis, which can power motions that lead to macroscopic detectable effects in a system, is a major endeavor in contemporary science. To move toward this goal, a host–guest system, composed of a nematic liquid crystal film doped with a chiral light-driven molecular motor, is assembled. Irradiation of the film results in unidirectional rotary motion of the molecular motor, which induces a motion of the mesogenic molecules leading to a molecular reorganization and, as a consequence, a change in the color of the film. In this way, by control of the rotary motion at the molecular level, color tuning over the entire visible spectrum is achieved. These findings demonstrate that a molecular motor can exert a visually observable macroscopic change in a material. PMID:11929969

  5. A charge transfer complex nematic liquid crystalline gel with high electrical conductivity (United States)

    Bhargavi, R.; Nair, Geetha G.; Krishna Prasad, S.; Majumdar, R.; Bag, Braja G.


    We describe the rheological, dielectric and elastic properties of a nematic liquid crystal gel created using an anthrylidene derivative of arjunolic acid, a chiral triterpenoid, obtained from the extracts of the wood of Terminalia arjuna. In this novel gel, having the electron-donor and acceptor components as minority constituents, the gelation and strengthening of charge-transfer complex (CTC) formation are seen to be occurring concomitantly. In addition to being mechanically strong with a large storage modulus, the gel with the maximized CTC exhibits Frank bend elastic constant values that approach nanonewton levels. The highlight of the study is the observation of 4-5 orders of magnitude increase in electrical conductivity for this gel, a value that is higher than even in the CT complexes of 2-d ordered columnar structures. A further important advantage of the present system over the columnar complex is that the high conductivity is seen for ac probing also, and owing to the nematic nature can be switched between its anisotropic limits. Some of these features are ascribed to a specific molecular packing architecture, which reduces the trapping of the charge carriers.

  6. A charge transfer complex nematic liquid crystalline gel with high electrical conductivity

    Energy Technology Data Exchange (ETDEWEB)

    Bhargavi, R.; Nair, Geetha G., E-mail:, E-mail:; Krishna Prasad, S., E-mail:, E-mail: [Centre for Nano and Soft Matter Sciences, Jalahalli, Bangalore 560013 (India); Majumdar, R.; Bag, Braja G. [Department of Chemistry and Chemical Technology, Vidyasagar University, Midnapore (W) 721 102 (India)


    We describe the rheological, dielectric and elastic properties of a nematic liquid crystal gel created using an anthrylidene derivative of arjunolic acid, a chiral triterpenoid, obtained from the extracts of the wood of Terminalia arjuna. In this novel gel, having the electron-donor and acceptor components as minority constituents, the gelation and strengthening of charge-transfer complex (CTC) formation are seen to be occurring concomitantly. In addition to being mechanically strong with a large storage modulus, the gel with the maximized CTC exhibits Frank bend elastic constant values that approach nanonewton levels. The highlight of the study is the observation of 4–5 orders of magnitude increase in electrical conductivity for this gel, a value that is higher than even in the CT complexes of 2-d ordered columnar structures. A further important advantage of the present system over the columnar complex is that the high conductivity is seen for ac probing also, and owing to the nematic nature can be switched between its anisotropic limits. Some of these features are ascribed to a specific molecular packing architecture, which reduces the trapping of the charge carriers.

  7. Reflection spectra and near-field images of a liquid crystalline half-Skyrmion lattice. (United States)

    Fukuda, Jun-Ichi; Žumer, Slobodan


    We investigate numerically the optical properties of a hexagonal half-Skyrmion lattice exhibited by a highly chiral liquid crystal confined between two parallel plates. Our study focuses on the near and far-field reflection for normally incident light with different polarizations. We show that, when the wavelength of the incident light is longer than a threshold value, the reflectivity is almost insensitive to the polarization of the incident light, although the intensity profiles of the reflected light, in particular in the near-field regime, depend significantly on the polarization. The former property is attributable to the quasi two-dimensional nature of the half-Skyrmion lattice, that is, almost uniform orientational order along the direction normal to the confining plates. Our results for the intensity of reflected light generated by evanescent as well as propagating contributions suggest that direct evidence of the formation and structure of half-Skyrmions could be provided by near-field optics with resolutions higher than that of conventional optical microscopy.

  8. Tuning the phase diagrams: the miscibility studies of multilactate liquid crystalline compounds

    Czech Academy of Sciences Publication Activity Database

    Bubnov, Alexej; Tykarska, M.; Hamplová, Věra; Kurp, K.


    Roč. 89, č. 9 (2016), s. 885-893 ISSN 0141-1594 R&D Projects: GA ČR GA13-14133S; GA MŠk(CZ) LD14007; GA ČR GA15-02843S Grant - others:EU - ICT(XE) COST Action IC1208 Institutional support: RVO:68378271 Keywords : miscibility study * binary mixture * polar smectic phase * lactic acid derivative * miscibility study * phase diagram * self-assembling behaviour Subject RIV: JJ - Other Materials Impact factor: 1.060, year: 2016

  9. Liquid crystalline perylene diimide outperforming nonliquid crystalline counterpart: higher power conversion efficiencies (PCEs) in bulk heterojunction (BHJ) cells and higher electron mobility in space charge limited current (SCLC) devices. (United States)

    Zhang, Youdi; Wang, Helin; Xiao, Yi; Wang, Ligang; Shi, Dequan; Cheng, Chuanhui


    In this work, we propose the application of liquid crystalline acceptors as a potential means to improve the performances of bulk heterojunction (BHJ) organic solar cells. LC-1, a structurally-simple perylene diimide (PDI), has been adopted as a model for thorough investigation. It exhibits a broad temperature range of liquid crystalline (LC) phase from 41 °C to 158 °C, and its LC properties have been characterized by differental scanning calorimetry (DSC), polarization optical microscopy (POM), and X-ray diffraction (XRD). The BHJ devices, using P3HT:LC-1 (1:2) as an organic photovoltaic active layer undergoing thermal annealing at 120 °C, shows an optimized efficiency of 0.94 %. By contrast, the devices based on PDI-1, a nonliquid crystalline PDI counterpart, only obtain a much lower efficiency of 0.22%. Atomic force microscopy (AFM) images confirm that the active layers composed of P3HT:LC-1 have smooth and ordered morphology. In space charge limited current (SCLC) devices fabricated via a spin-coating technique, LC-1 shows the intrinsic electron mobility of 2.85 × 10(-4) cm(2)/(V s) (at 0.3 MV/cm) which is almost 5 times that of PDI-1 (5.83 × 10(-5) cm(2)/(V s)) under the same conditions for thermal annealing at 120 °C.

  10. Calculation of the Standard Molal Thermodynamic Properties of Crystalline, Liquid, and Gas Organic Molecules at High Temperatures and Pressures (United States)

    Helgeson, Harold C.; Owens, Christine E.; Knox, Annette M.; Richard, Laurent


    Calculation of the thermodynamic properties of organic solids, liquids, and gases at high temperatures and pressures is a requisite for characterizing hydrothermal metastable equilibrium states involving these species and quantifying the chemical affinities of irreversible reactions of organic molecules in natural gas, crude oil, kerogen, and coal with minerals and organic, inorganic, and biomolecular aqueous species in interstitial waters in sedimentary basins. To facilitate calculations of this kind, coefficients for the Parameters From Group Contributions (PFGC) equation of state have been compiled for a variety of groups in organic liquids and gases. In addition, molecular weights, critical temperatures and pressures, densities at 25°C and 1 bar, transition, melting, and boiling temperatures ( Tt,Pr, Tm,Pr, and Tv,Pr, respectively) and standard molal enthalpies of transition (Δ H° t,Pr), melting (Δ H° m,Pr), and vaporization (Δ H° v,Pr) of organic species at 1 bar ( Pr) have been tabulated, together with an internally consistent and comprehensive set of standard molal Gibbs free energies and enthalpies of formation from the elements in their stable state at 298.15 K ( Tr) and Pr (Δ G° f and Δ H° f, respectively). The critical compilation also includes standard molal entropies ( S°) and volumes ( V°) at Tr and Pr, and standard molal heat capacity power function coefficients to compute the standard molal thermodynamic properties of organic solids, liquids, and gases as a function of temperature at 1 bar. These properties and coefficients have been tabulated for more than 500 crystalline solids, liquids, and gases, and those for many more can be computed from the equations of state group additivity algorithms. The crystalline species correspond to normal alkanes (C nH 2( n+1) ) with carbon numbers ( n, which is equal to the number of moles of carbon atoms in one mole of the species) ranging from 5 to 100, and 23 amino acids including glycine (C 2H 5NO

  11. Peptide KSL-W-Loaded Mucoadhesive Liquid Crystalline Vehicle as an Alternative Treatment for Multispecies Oral Biofilm

    Directory of Open Access Journals (Sweden)

    Jéssica Bernegossi


    Full Text Available Decapeptide KSL-W shows antibacterial activities and can be used in the oral cavity, however, it is easily degraded in aqueous solution and eliminated. Therefore, we aimed to develop liquid crystalline systems (F1 and F2 for KSL-W buccal administration to treat multispecies oral biofilms. The systems were prepared with oleic acid, polyoxypropylene (5 polyoxyethylene (20 cetyl alcohol (PPG-5-CETETH-20, and a 1% poloxamer 407 dispersion as the oil phase (OP, surfactant (S, and aqueous phase (AP, respectively. We characterized them using polarized light microscopy (PLM, small-angle X-ray scattering (SAXS, rheology, and in vitro bioadhesion, and performed in vitro biological analysis. PLM showed isotropy (F1 or anisotropy with lamellar mesophases (F2, confirmed by peak ratio quantification using SAXS. Rheological tests demonstrated that F1 exhibited Newtonian behavior but not F2, which showed a structured AP concentration-dependent system. Bioadhesion studies revealed an AP concentration-dependent increase in the system’s bioadhesiveness (F2 = 15.50 ± 1.00 mN·s to bovine teeth blocks. Antimicrobial testing revealed 100% inhibition of multispecies oral biofilm growth after KSL-W administration, which was incorporated in the F2 aqueous phase at a concentration of 1 mg/mL. Our results suggest that this system could serve as a potential vehicle for buccal administration of antibiofilm peptides.

  12. Chiral liquid-crystalline polyacrylates from (S-(--2-methyl-1-butanol. Synthesis, mesomorphic properties and light scattering

    Directory of Open Access Journals (Sweden)

    Merlo Aloir A.


    Full Text Available The synthesis and mesomorphic behavior of two chiral side chain liquid crystalline polyacrylates from (S-(--2-methyl-1-butanol are described. These new polyacrylates show a dependence of the phase transition temperatures on both, molecular weight and spacer length. The polyacrylate with four methylene units in the spacer exhibits a chiral nematic phase whereas the polyacrylate with a spacer containing eleven methylene units presents a smectic phase. In addition, the chiral nematic phase appears for low molecular weight and smectic phase for high molecular weight polyacrylates. Light scattering experiments were performed in dilute solutions of the polyacrylate containing eleven methylene units in tetrahydrofuran and dichloromethane. Values for weight averaged molecular weight, radius of gyration and second virial coefficient were determined by static light scattering whereas the diffusion coefficient and the hydrodynamic radius of the chains were obtained by photon correlation spectroscopy. A comparison between both techniques indicates that the chain behavior can be taken as typical for a polydisperse linear chain in a good solvent.

  13. Liquid crystalline graphene oxide/PEDOT:PSS self-assembled 3D architecture for binder-free supercapacitor electrodes

    Directory of Open Access Journals (Sweden)

    Monirul eIslam


    Full Text Available Binder-free self-assembled 3D architecture electrodes have been fabricated by a novel convienient method. Liquid crystalline graphene oxide (LC GO was used as precursor to interact with poly(3,4-ethylene-dioxythiophene:poly(styrenesulfonate (PEDOT:PSS in dispersion in order to form a conductive polymer entrapped, self-assembled layer-by-layer structure. This advanced network containing PEDOT:PSS enabled us to ascribe the superior electrochemical properties of particular graphene sheets. This layer-by-layer self-assembled 3D architecture of best performing composite (rGO-PEDOT:PSS 25 showed excellent electrochemical performance of 434 F g-1 through chemical treatment. To highlight these advances, we further explored the practicality of the as-prepared electrode by varying the composite material content. An asymmetric supercapacitor device using aqueous electrolyte was also studied of this same composite. The resulting performance from this set up included a specific capacitance of 132 F g-1. Above all, we observed an increase in specific capacitance (19% with increase in cycle life emphasizing the excellent stability of this device.

  14. Crystalline Electric-Field Randomness in the Triangular Lattice Spin-Liquid YbMgGaO_{4}. (United States)

    Li, Yuesheng; Adroja, Devashibhai; Bewley, Robert I; Voneshen, David; Tsirlin, Alexander A; Gegenwart, Philipp; Zhang, Qingming


    We apply moderate-high-energy inelastic neutron scattering (INS) measurements to investigate Yb^{3+} crystalline electric field (CEF) levels in the triangular spin-liquid candidate YbMgGaO_{4}. Three CEF excitations from the ground-state Kramers doublet are centered at the energies ℏω=39, 61, and 97 meV in agreement with the effective spin-1/2 g factors and experimental heat capacity, but reveal sizable broadening. We argue that this broadening originates from the site mixing between Mg^{2+} and Ga^{3+} giving rise to a distribution of Yb-O distances and orientations and, thus, of CEF parameters that account for the peculiar energy profile of the CEF excitations. The CEF randomness gives rise to a distribution of the effective spin-1/2 g factors and explains the unprecedented broadening of low-energy magnetic excitations in the fully polarized ferromagnetic phase of YbMgGaO_{4}, although a distribution of magnetic couplings due to the Mg/Ga disorder may be important as well.

  15. Constant-pressure simulations of Gay-Berne liquid-crystalline phases in cylindrical nanocavities. (United States)

    Karjalainen, Jouni; Lintuvuori, Juho; Telkki, Ville-Veikko; Lantto, Perttu; Vaara, Juha


    Applications of liquid crystals (LCs) are based on controlling the orientational and translational order of the medium. One important way of control is via confinement. In this work, uniaxial thermotropic LCs confined to nanosized cylindrical cavities are studied using isobaric parallel tempering (PT) Monte Carlo (MC) simulations. The LCs are modeled using the Gay-Berne (4.4, 20.0, 1, 1) (GB) potential in long, smooth-walled cavities. The chosen particle-wall interaction favours homogeneous planar anchoring - the alignment of molecules along the wall. We report the results for the phase structure appropriate to three different cavity sizes as well as comparison to the results of bulk simulations. Ensemble averages for orientational and translational order parameters as well as their local behavior as a function of the distance to the cavity wall is calculated by reweighting results from all the simulated temperatures. We find that the LC director tends to align strongly with the axis of the cylindrical cavity. The orientational order is enhanced and translational order suppressed by the walls of the cavity. Hence, there are notable differences between the local order close to the wall and near the cylinder axis. The position-dependent distributions of the order parameters result in smooth phase transitions in their respective system-wide averages. Particularly, the nematic-isotropic (N-I) transition is replaced by a continuous nematic-paranematic (N-PN) transition. This is caused by the core region of the cavities becoming isotropic at high temperatures, whereas near the wall the LC retains nematic order. In contrast to previous NVT ensemble simulations, we find the effect of confinement on the smectic (Sm) layering to be weak. Also, Sm-N and N-PN transitions are found to be both sharper and residing at higher temperatures than in the constant-volume simulations. At temperatures where the bulk LC is a solid, we observe a wall-induced density wave in the confined

  16. Growth of isotropic domains as a mechanism of dynamic diffraction grating recording in low molecular liquid-crystalline derivatives of azobenzene. (United States)

    Czajkowski, Maciej; Bartkiewicz, Stanislaw; Mysliwiec, Jaroslaw


    In this paper, we propose and explain the mechanism of dynamic molecular motions and isotropic domain formation during the diffraction grating recording in low molecular liquid-crystalline azobenzene derivatives. The photochromic molecules of 4-heptyl-4'-methoxyazobenzene, showing nematic liquid-crystalline properties close to the room temperature (from T = 34 °C), are used. A one-dimensional model of the grating formation is formulated based on in vivo polarized microscope observations. Formation and growth of the isotropic domains induced by the sinusoidally modulated Gaussian light intensity distribution is proposed as the mechanism and is used for experimental data fitting. The influence of the recording light intensity, grating period, and temperature on the domain growth rate factor is checked. © 2012 American Chemical Society

  17. Modulating alignment of membrane proteins in liquid-crystalline and oriented gel media by changing the size and charge of phospholipid bicelles

    Energy Technology Data Exchange (ETDEWEB)

    Lorieau, Justin L.; Maltsev, Alexander S.; Louis, John M.; Bax, Ad, E-mail: [National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, Laboratory of Chemical Physics (United States)


    We demonstrate that alignment of a structured peptide or small protein solubilized in mixed phospholipid:detergent micelles or bicelles, when embedded in a compressed gel or liquid crystalline medium, can be altered by either changing the phospholipid aggregate shape, charge, or both together. For the hemagglutinin fusion peptide solubilized in bicelles, we show that bicelle shape and charge do not change its helical hairpin structure but impact its alignment relative to the alignment medium, both in charged compressed acrylamide gel and in liquid crystalline d(GpG). The method can be used to generate sets of residual dipolar couplings that correspond to orthogonal alignment tensors, and holds promise for high-resolution structural refinement and dynamic mapping of membrane proteins.

  18. Atomic force and optical near-field microscopic investigations of polarization holographic gratings in a liquid crystalline azobenzene side-chain polyester

    DEFF Research Database (Denmark)

    Ramanujam, P.S.; Holme, N.C.R.; Hvilsted, S.


    Atomic force and scanning near-field optical microscopic investigations have been carried out on a polarization holographic grating recorded in an azobenzene side-chain Liquid crystalline polyester. It has been found that immediately following laser irradiation, a topographic surface grating......-field optical microscopic scanning of the grating reveals, however, that the bulk of the film remains optically anisotropic. (C) 1996 American Institute of Physics....

  19. The importance of orientation in proton transport of a polymer film based on an oriented self-organized columnar liquid-crystalline polyether

    Energy Technology Data Exchange (ETDEWEB)

    Tylkowski, Bartosz; Castelao, Nuria [Departament d' Enginyeria Quimica, Universitat Rovira i Virgili, Av. Paiesos Catalans, 26, E-43007, Tarragona (Spain); Giamberini, Marta, E-mail: [Departament d' Enginyeria Quimica, Universitat Rovira i Virgili, Av. Paiesos Catalans, 26, E-43007, Tarragona (Spain); Garcia-Valls, Ricard [Departament d' Enginyeria Quimica, Universitat Rovira i Virgili, Av. Paiesos Catalans, 26, E-43007, Tarragona (Spain); Reina, Jose Antonio [Departament de Quimica Analitica i Quimica Organica, Universitat Rovira i Virgili, Carrer Domingo s/n, E-43007, Tarragona (Spain); Gumi, Tania [Departament d' Enginyeria Quimica, Universitat Rovira i Virgili, Av. Paiesos Catalans, 26, E-43007, Tarragona (Spain)


    We prepared membranes based on a liquid-crystalline side-chain polyether obtained by chemical modification of commercial poly(epichlorohydrin) (PECH) with dendrons. This polymer exhibited a columnar structure, which could form an ion channel in the inner part. The columns were successfully oriented by taking advantage of surface interactions between the polymer and hydrophilic substrates, as confirmed by X-ray diffraction analysis (XRD), environmental scanning electron microscopy (ESEM) and optical microscopy between crossed polars (POM). Column orientation was found to be crucial for effective transport: the oriented membranes exhibited proton transport comparable to that of Nafion Registered-Sign N117 and no water uptake. An increase in sodium ion concentration in the feed phase suggested a proton/cation antiport. On the contrary, no proton transport was detected on unoriented membranes based on the same liquid-crystalline side-chain polyether or on unmodified PECH. - Highlights: Black-Right-Pointing-Pointer We prepared oriented membranes based on a liquid crystalline columnar polyether. Black-Right-Pointing-Pointer In this structure, the inner polyether chain could work as an ion channel. Black-Right-Pointing-Pointer We obtained membranes by casting a chloroform solution in the presence of water. Black-Right-Pointing-Pointer Membranes showed good proton permeability due to the presence of oriented channels.

  20. Structure-property relations in siloxane-based main chain liquid crystalline elastomers and related linear polymers (United States)

    Ren, Wanting


    Soft materials have attracted much scientific and technical interest in recent years. In this thesis, attention has been placed on the underpinning relations between molecular structure and properties of one type of soft matter---main chain liquid crystalline elastomers (MCLCEs), which may have application as shape memory or as auxetic materials. In this work, a number of siloxane-based MCLCEs and their linear polymer analogues (MCLCEs) with chemical variations were synthesized and examined. Among these chemical variations, rigid p-phenylene transverse rod and flat-shaped anthraquinone (AQ) mesogenic monomers were specifically incorporated. Thermal and X-ray analysis found a smectic C phase in most of our MCLCEs, which was induced by the strong self-segregation of siloxane spacers, hydrocarbon spacers and mesogenic rods. The smectic C mesophase of the parent LCE was not grossly affected by terphenyl transverse rods. Mechanical studies of MCLCEs indicated the typical three-region stress-strain curve and a polydomain-to-monodomain transition. Strain recovery experiments of MCLCEs showed a significant dependence of strain retentions on the initial strains but not on the chemical variations, such as the crosslinker content and the lateral substituents on mesogenic rods. The MCLCE with p-phenylene transverse rod showed a highly ordered smectic A mesophase at room temperature with high stiffness. Mechanical properties of MCLCEs with AQ monomers exhibit a strong dependence on the specific combination of hydrocarbon spacer and siloxane spacer, which also strongly affect the formation of pi-pi stacking between AQ units. Poisson's ratio measurement over a wide strain range found distinct trends of Poisson's ratio as a function of the crosslinker content as well as terphenyl transverse rod loadings in its parent MCLCEs.

  1. The microwave heating mechanism of N-(4-methoxybenzyliden)-4-butylaniline in liquid crystalline and isotropic phases as determined using in situ microwave irradiation NMR spectroscopy. (United States)

    Tasei, Yugo; Tanigawa, Fumikazu; Kawamura, Izuru; Fujito, Teruaki; Sato, Motoyasu; Naito, Akira


    Microwave heating effects are widely used in the acceleration of organic, polymerization and enzymatic reactions. These effects are primarily caused by the local heating induced by microwave irradiation. However, the detailed molecular mechanisms associated with microwave heating effects on the chemical reactions are not yet well understood. This study investigated the microwave heating effect of N-(4-methoxybenzylidene)-4-butylaniline (MBBA) in liquid crystalline and isotropic phases using in situ microwave irradiation nuclear magnetic resonance (NMR) spectroscopy, by obtaining (1)H NMR spectra of MBBA under microwave irradiation. When heated simply using the temperature control unit of the NMR instrument, the liquid crystalline MBBA was converted to the isotropic phase exactly at its phase transition temperature (Tc) of 41 °C. The application of microwave irradiation at 130 W for 90 s while maintaining the instrument temperature at 20 °C generated a small amount of isotropic phase within the bulk liquid crystal. The sample temperature of the liquid crystalline state obtained during microwave irradiation was estimated to be 35 °C by assessing the linewidths of the (1)H NMR spectrum. This partial transition to the isotropic phase can be attributed to a non-equilibrium local heating state induced by the microwave irradiation. The application of microwave at 195 W for 5 min to isotropic MBBA while maintaining an instrument temperature of 50 °C raised the sample temperature to 160 °C. In this study, the MBBA temperature during microwave irradiation was estimated by measuring the temperature dependent chemical shifts of individual protons in the sample, and the different protons were found to indicate significantly different temperatures in the molecule. These results suggest that microwave heating polarizes bonds in polar functional groups, and this effect may partly explain the attendant acceleration of organic reactions.

  2. Development and characterization of p1025-loaded bioadhesive liquid-crystalline system for the prevention ofStreptococcus mutansbiofilms. (United States)

    Calixto, Giovana Maria Fioramonti; Duque, Cristiane; Aida, Kelly Limi; Dos Santos, Vanessa Rodrigues; Massunari, Loiane; Chorilli, Marlus


    Formation of a dental biofilm by Streptococcus mutans can cause dental caries, and remains a costly health problem worldwide. Recently, there has been a growing interest in the use of peptidic drugs, such as peptide p1025, analogous to the fragments 1025-1044 of S. mutans cellular adhesin, responsible for the adhesion and formation of dental biofilm. However, peptides have physicochemical characteristics that may affect their biological action, limiting their clinical performance. Therefore, drug-delivery systems, such as a bioadhesive liquid-crystalline system (LCS), may be attractive strategies for peptide delivery. Potentiation of the action of LCS can be achieved with the use of bioadhesive polymers to prolong their residence on the teeth. In line with this, three formulations - polyoxypropylene-(5)-polyoxyethylene-(20)-cetyl alcohol, oleic acid, and Carbopol C974P in different combinations (F1C, F2C, and F3C) were developed to observe the influence of water in the LCS, with the aim of achieving in situ gelling in the oral environment. These formulations were assessed by polarized light microscopy, small-angle X-ray scattering, rheological analysis, and in vitro bioadhesion analysis. Then, p1025 and a control (chlorhexidine) were incorporated into the aqueous phase of the formulation (F + p1025 and F + chlorhexidine), to determine their antibiofilm effect and toxicity on epithelial cells. Polarized light microscopy and small-angle X-ray scattering showed that F1C and F2C were LCS, whereas F3C was a microemulsion. F1C and F2C showed pseudoplastic behavior and F3C Newtonian behavior. F1C showed the highest elastic and bioadhesive characteristics compared to other formulations. Antibiofilm effects were observed for F + p1025 when applied in the surface-bound salivary phase. The p1025-loaded nanostructured LCS presented limited cytotoxicity and effectively reduced S. mutans biofilm formation, and could be a promising p1025-delivery strategy to prevent the formation

  3. Molecular Control of Liquid Crystalline Orientation of Poly(p-phenylene- 2,6-benzobisoxazole) and Poly(p-phenylene-2,6-benzobisthiazole). (United States)


    Textile and Fiber Engineering Atlanta, GA 30332 To be Published in Polymer Preprints Spring 1993 November 30, 1992 Reproduction in whole, or in part...Report 4. lIlt I APIII 51.DIIhIWtI 5. jNO’N wqeuum; Molecular Control of the Liquid Crystalline Orientation of Polybenzoxazoles Grant* N-00014-91-J...APeluAlw3ft Norris Brown College GeorgTh Institute of ’’ ’’ Department of Chemistry Tech. School of Textil Atlanta, GA 30314 and Fiber Engineering

  4. Enhanced antitumor efficacy and counterfeited cardiotoxicity of combinatorial oral therapy using Doxorubicin- and Coenzyme Q10-liquid crystalline nanoparticles in comparison with intravenous Adriamycin

    DEFF Research Database (Denmark)

    Swarnakar, Nitin K; Thanki, Kaushik; Jain, Sanyog


    and strong synergism for combination at 1:10 dose ratio owing to higher cellular uptake, nuclear colocalization, higher apoptotic index and 8-OHdG levels. The prophylactic antitumor efficacy of the CoQ10-LCNPs was also established using tumor induction and progression studies. Finally, therapeutic antitumor......, with Dox-induced-cardiotoxicity was completely counterfeited in combination. In nutshell, LCNPs pose great potential in improving the therapeutic efficacy of drugs by oral route of administration. FROM THE CLINICAL EDITOR: This study describes the use of liquid crystalline nanoparticles containing coenzyme...

  5. Influence of a change in helical twisting power of photoresponsive chiral dopants on rotational manipulation of micro-objects on the surface of chiral nematic liquid crystalline films. (United States)

    Thomas, Reji; Yoshida, Yohei; Akasaka, Takehito; Tamaoki, Nobuyuki


    Herein we report a group of five planar chiral molecules as photon-mode chiral switches for the reversible control of the self-assembled superstructures of doped chiral nematic liquid crystals. The chiral switches are composed of an asymmetrically substituted aromatic moiety and a photoisomerizing azobenzene unit connected in a cyclic manner through methylene spacers of varying lengths. All the molecules show conformational restriction in the rotation of the asymmetrically substituted aromatic moiety in both the E and Z states of the azobenzene units resulting in planar chirality with separable enantiomers. Our newly synthesized compounds in pure enantiomeric form show high helical twisting power (HTP) in addition to an improved change in HTP between the E and Z states. The molecule with a diphenylnaphthalene unit shows the highest ever known initial helical twisting power among chiral dopants with planar chirality. In addition to the reversible tuning of reflection colors, we employed the enantiomers of these five compounds in combination with four nematic liquid crystalline hosts to study their properties as molecular machines; the change in HTP of the chiral dopant upon photoisomerization induces rotation of the texture of the liquid crystal surfaces. Importantly, this study has revealed a linear dependence of the ratio of the difference between HTPs before and after irradiation against the absolute value of the initial HTP, not the absolute value of the change in helical twisting power between two states, on the angle of rotation of micro-objects on chiral nematic liquid crystalline films. This study has also revealed that a change in irradiation intensity does not affect the maximum angle of rotation, but it does affect the speed of rotational reorganization of the cholesteric helix. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. A structurally diverse library of safe-by-design citrem-phospholipid lamellar and non-lamellar liquid crystalline nano-assemblies

    DEFF Research Database (Denmark)

    Mat Azmi, Intan Diana Binti; Wibroe, Peter Popp; Wu, Lin-Ping


    Non-lamellar liquid crystalline aqueous nanodispersions, known also as ISAsomes (internally self-assembled 'somes' or nanoparticles), are gaining increasing interest in drug solubilisation and bio-imaging, but they often exhibit poor hemocompatibility and induce cytotoxicity. This limits their ap......Non-lamellar liquid crystalline aqueous nanodispersions, known also as ISAsomes (internally self-assembled 'somes' or nanoparticles), are gaining increasing interest in drug solubilisation and bio-imaging, but they often exhibit poor hemocompatibility and induce cytotoxicity. This limits...... their applications in intravenous drug delivery and targeting. Using a binary mixture of citrem and soy phosphatidylcholine (SPC) at different weight ratios, we describe a library of colloidally stable aqueous and hemocompatible nanodispersions of diverse nanoarchitectures (internal self-assembled nanostructures......). This engineered library is structurally stable in human plasma as well as being hemocompatible (non-hemolytic, and poor activator of the complement system). By varying citrem to lipid weight ratio, the nanodispersion susceptibility to macrophage uptake could also be modulated. Finally, the formation...

  7. New photoresponsible polymers based on the polymerisable azo-diphenyldiacetylene (AZ-DPDA) liquid crystalline monomers for rewritable holograms (Conference Presentation) (United States)

    Kim, Jinsoo; Ka, Jae-Won; Kim, Yun Ho; Kim, Yeong-Joon; Seo, Young Beom


    The development of high performance and large area photoresponsive materials for hologram have been one of the great challenges in order to realize holographic 3D display technology which needs no special eyewear. Desirable hologram materials should provide the high diffraction efficiency, fast response, high resolution, stable and reversible storage, low-energy consuming in the recording and reading processes as well as easy mass production. Azobenzene-containing polymers has been recognized as one of the promising candidate materials for holography because they can modulate effectively due to the photosensitivity and reversibility of azo moieties. In addition, polymer systems have several advantages such as simple fabrication, flexibility, thermal stability, and large scale production. It has been reported that highly birefringent azotolan-containing liquid crystalline polymer (LCP) film can induce a large change in refractive index upon exposure to actinic light. Analogously, we prepared new photochromic polymers based on the polymerisable liquid crystalline acrylate monomers (RMs) containing azo and highly birefringent diphenyldiacetylen (DPDA) mesogenic units connected directly. Evaluation of new polymers for rewritable hologram media will be discussed.

  8. Structural Features and the Anti-Inflammatory Effect of Green Tea Extract-Loaded Liquid Crystalline Systems Intended for Skin Delivery

    Directory of Open Access Journals (Sweden)

    Patricia Bento da Silva


    Full Text Available Camellia sinensis, which is obtained from green tea extract (GTE, has been widely used in therapy owing to the antioxidant, chemoprotective, and anti-inflammatory activities of its chemical components. However, GTE is an unstable compound, and may undergo reactions that lead to a reduction or loss of its effectiveness and even its degradation. Hence, an attractive approach to overcome this problem to protect the GTE is its incorporation into liquid crystalline systems (LCS that are drug delivery nanostructured systems with different rheological properties, since LCS have both fluid liquid and crystalline solid properties. Therefore, the aim of this study was to develop and characterize GTE-loaded LCS composed of polyoxypropylene (5 polyoxyethylene (20 cetyl alcohol, avocado oil, and water (F25E, F29E, and F32E with different rheological properties and to determine their anti-inflammatory efficacy. Polarized light microscopy revealed that the formulations F25, F29, and F32 showed hexagonal, cubic, and lamellar liquid crystalline mesophases, respectively. Rheological studies showed that F32 is a viscous Newtonian liquid, while F25 and F29 are dilatant and pseudoplastic non-Newtonian fluids, respectively. All GTE-loaded LCS behaved as pseudoplastic with thixotropy; furthermore, the presence of GTE increased the S values and decreased the n values, especially in F29, indicating that this LCS has the most organized structure. Mechanical and bioadhesive properties of GTE-unloaded and -loaded LCS corroborated the rheological data, showing that F29 had the highest mechanical and bioadhesive values. Finally, in vivo inflammation assay revealed that the less elastic and consistent LCS, F25E and F32E presented statistically the same anti-inflammatory activity compared to the positive control, decreasing significantly the paw edema after 4 h; whereas, the most structured and elastic LCS, F29E, strongly limited the potential effects of GTE. Thereby, the

  9. Supramolecular liquid crystalline π-conjugates: the role of aromatic π-stacking and van der Waals forces on the molecular self-assembly of oligophenylenevinylenes. (United States)

    Goel, Mahima; Jayakannan, M


    Here, we report a unique design strategy to trace the role of aromatic π-stacking and van der Waals interactions on the molecular self-organization of π-conjugated building blocks in a single system. A new series of bulky oligophenylenevinylenes (OPVs) bearing a tricyclodecanemethylene (TCD) unit in the aromatic π-core with flexible long methylene chains (n = 0-12 and 16) in the longitudinal position were designed and synthesized. The OPVs were found to be liquid crystalline, and their enthalpies of phase transitions (also entropies) showed odd-even oscillation with respect to the number of carbon atoms in alkyl chains. OPVs with an even number of methylene units in the side chains showed higher enthalpies with respect to their highly packed solid structures compared to odd-numbered ones. Polarized light microscopic analysis confirmed the formation of cholesteric liquid crystalline (LC) phases of fan shaped textures with focal conics in OPVs with 5 ≤ n ≤ 9. OPVs with longer alkyl chains (OPV-10 to OPV-12) produced a birefringence pattern consisting of dark and bright ring-banded suprastructures. The melting temperature followed a sigmoidal trend, indicating the transformation of molecular self-organization in OPVs from solid to ring-banded suprastructures via cholesteric LC intermediates. At longer alkyl chain lengths, the van der Waals interactions among the alkyl chains became predominant and translated the mesogenic effect across the lamellae; as a consequence, the lamellae underwent twisted self-organization along the radial growth direction of the spherulites to produce bright and dark bands. Scanning electron microscope (SEM) analysis of cholesteric LC and ring-banded textures strongly supported the existence of twisted lamellae in the OPVs with ring-banded textures. Variable temperature X-ray diffraction analysis confirmed the reversibility of the molecular self-organization in the solid state and also showed the existence of the higher ordered

  10. Desenvolvimento de sistemas líquido-cristalinos empregando silicone fluido de co-polímero glicol e poliéter funcional siloxano Development of liquid-crystalline systems using silicon glycol copolymer and polyether functional siloxane

    Directory of Open Access Journals (Sweden)

    Marlus Chorilli


    Full Text Available For the construction of the phase diagrams, the method of the aqueous titration was used. There were prepared 5 ternary diagrams, varying the surfactant and the oil phase. The liquid-crystalline phases were identified by polarized light microscopy. The formulations prepared with silicon glycol copolymer, polyether functional siloxane (PFS and water (S1 and with diisopropyl adipate, PFS and water (S4 presented liquid-crystalline phases with lamellar arrangement. Moreover, after 15 days in hot oven (37 ºC, the formulations presented hexagonal arrangement, evidencing the influence of the temperature in the organization of the system.

  11. Isotonic tube feeding formula induces liquid stool in normal subjects: reversal by pectin. (United States)

    Zimmaro, D M; Rolandelli, R H; Koruda, M J; Settle, R G; Stein, T P; Rombeau, J L


    Diarrhea is one of the most common complications in patients who receive tube-feeding formulas. Since the colon is the final site of water and electrolyte absorption and ultimately determines fecal composition, diarrhea during tube feeding may result from altered colonic function. The lack of dietary fiber, such as pectin, in tube-feeding formulas may be one of the means by which colonic function is affected. The purpose of this study was to determine the effect of a standard, liquid, commercially available, isotonic tube-feeding formula (ITFF) and the effects of supplementing the ITFF with pectin on colonic function as measured by stool consistency and colonic fluid composition in 13 normal adults. Data were obtained when subjects consumed their regular diet, ITFF, and ITFF supplemented with pectin using the technique of in vivo dialysis of colonic fluid. Ingestion of the ITFF resulted in a significant increase in the percentage of liquid stools compared to a regular diet [median (interquartile range) = 0% (0), 60% (64); p less than 0.01]. Ingestion of the ITFF also resulted in significant decreases in the concentrations of sodium, potassium, and short-chain fatty acids, and increases in pH and osmotic gap in colonic fluid compared to the subjects' regular diet. Supplementing the ITFF with pectin significantly reduced the incidence of liquid stools [0% (0)] and promoted a normalization of colonic fluid composition. The results suggest that the addition of pectin may enhance tolerance to ITFFs.

  12. Observations of cavity polaritons in one-dimensional photonic crystals containing a liquid-crystalline semiconductor based on perylene bisimide units (United States)

    Sakata, T.; Suzuki, M.; Yamamoto, T.; Nakanishi, S.; Funahashi, M.; Tsurumachi, N.


    We investigated the optical transmission properties of one-dimensional photonic crystal (1D-PC) microcavity structures containing the liquid-crystalline (LC) perylene tetracarboxylic bisimide (PTCBI) derivative. We fabricated the microcavity structures for this study by two different methods and observed the cavity polaritons successfully in both samples. For one sample, since the PTCBI molecules were aligned in the cavity layer of the 1D-PC by utilizing a friction transfer method, vacuum Rabi splitting energy was strongly dependent on the polarization of the incident light produced by the peculiar optical features of the LC organic semiconductor. For the other sample, we did not utilize the friction transfer method and did not observe such polarization dependence. However, we did observe a relatively large Rabi splitting energy of 187 meV, probably due to the improvement of optical confinement effect.

  13. A lipid-based liquid crystalline matrix that provides sustained release and enhanced oral bioavailability for a model poorly water soluble drug in rats. (United States)

    Boyd, Ben J; Khoo, Shui-Mei; Whittaker, Darryl V; Davey, Greg; Porter, Christopher J H


    Liquid crystalline phases that are stable in excess water, formed using lipids such as glyceryl monooleate (GMO) and oleyl glycerate (OG), are known to provide a sustained release matrix for poorly water soluble drugs in vitro, yet there has been no report of the use of these materials to impart oral sustained release behaviour in vivo. In the first part of this study, in vitro lipolysis experiments were used to compare the digestibility of GMO with a second structurally related lipid, oleyl glycerate, which was found to be less susceptible to hydrolysis by pancreatic lipase than GMO. Subsequent oral bioavailability studies were conducted in rats, in which a model poorly water soluble drug, cinnarizine (CIN), was administered orally as an aqueous suspension, or as a solution in GMO or OG. In the first bioavailability study, plasma samples were taken over a 30 h period and CIN concentrations determined by HPLC. Plasma CIN concentrations after administration in the GMO formulation were only sustained for a few hours after administration while for the OG formulation, the plasma concentration of cinnarizine was at its highest level 30 h after dosing, and appeared to be increasing. A second study in which CIN was again administered in OG, and plasma samples taken for 120 h, revealed a Tmax for CIN in rats of 36 h and a relative oral bioavailability of 344% when compared to the GMO formulation (117%) and the aqueous suspension formulation (assigned a nominal bioavailability of 100%). The results indicate that lipids that form liquid crystalline structures in excess water, may have application as an oral sustained release delivery system, providing they are not digested rapidly on administration.

  14. Controlling the color of cholesteric liquid-crystalline films by photoirradiation of a chiroptical molecular switch used as dopant

    NARCIS (Netherlands)

    van Delden, RA; Huck, NPM; Feringa, BL; Delden, Richard A. van; Gelder, Marc B. van; Huck, Nina P.M.

    Using thin films of a cholesteric mixture of acrylates 2 and 3 doped with the chiroptical molecular switch (M)-trans-1, photo-control of the reflection color between red and green is possible. This doped liquid-crystal (LC) film can be used for photoinduced writing, color reading, and photoinduced

  15. ARTICLE Photoreaction Behaviors of Two Liquid Crystalline Cinnamoyl Compounds with Different Phase in Solution and Mesomorphic States (United States)

    Dong, Xiao-ming; Guo, Jin-bao; Wei, Jie


    A novel nematic liquid crystal compound containing a cinnamoyl moiety (PCPC) and a typically cholesteric liquid crystal cholesteryl cinnamate (CC) were synthesized to explore the mechanism ofcinnamoyl compounds, and the chemical structures of photodimerization were confirmed by Fourier transform infrared spectroscopy and 1H nuclear magnetic resonance spectral analysis. The photoreaction behaviors of these two cinnamoyl compounds in mesomorphic state and solution were investigated, UV-Vis spectral analysis was used to analyze the photoproduct. The results show that the photochemistry of PCPC in nematic state involves both photodimerization and photoisomerization, while CC shows a complex reaction which can be divided into three parts, and this has enabled us to present new data and interpretations regarding the [2+2] photocycloaddition reaction. Additionally, the results of UV-Vis spectral analysis in solutions strongly suggest that UV-Vis spectral analysis can be used to study the kinetic behaviors of cinnamoyl moiety photoreaction.

  16. Combined main-chain/side-chain ionic liquid crystalline polymer based on ‘jacketing’ effect: Design, synthesis, supra-molecular self-assembly and photophysical properties

    Directory of Open Access Journals (Sweden)

    L. Weng


    Full Text Available Reasonably fabricating ordered structures of ionic polymers is very important for the development of novel functional materials. By combining the ions and liquid cry stalline polymer, we successfully designed and synthesized a series of novel combined main-chain/side-chain ionic liquid crystalline polymer (MCSC-ILCPs containing imidazolium groups and different counter-anions, poly (2,5-bis{[6-(4-butoxy-4'-imidazolium biphenylhexyl]oxycarbonyl}styrene salts poly(BImBHCS-X with the following types of counter-anions (Br¯, BF4¯, PF6¯ and TFSI¯. Combined technologies confirmed the chemical structures of the monomers and polymers with imidazolium cation and different counter-anions. Differential scanning calorimetry (DSC, polarized light microscopy (PLM and one- and two-dimensional wide-angle X-ray diffraction (1D and 2D WAXD results illustrated that the LC structures and the transitions of ordered structures depended on the nature of the counter-anion employed. The polymers with Br¯ and BF4¯ counter-anions exhibited smectic A (SmA LC behavior below the isotropic temperature. The another one, poly(BImBHCS–TFSI with the large volume of the TFSI¯ anion destroyed the packing of the LC ordered structure resulting in an amorphous structure. The photophysical properties of the polymers prepared can be adjusted by tuning the ionic interaction of the polymers by switching the counter-anion.

  17. One-dimensional iron(II) compounds exhibiting spin crossover and liquid crystalline properties in the room temperature region. (United States)

    Seredyuk, M; Gaspar, A B; Ksenofontov, V; Galyametdinov, Y; Verdaguer, M; Villain, F; Gütlich, P


    A novel series of 1D Fe(II) metallomesogens have been synthesized using the ligand 5-bis(alkoxy)- N-(4 H-1,2,4-triazol-4-yl)benzamide (C n -tba) and the Fe(X) 2. sH 2O salts. The polymers obey the general formula [Fe(C n -tba) 3](X) 2. sH 2O [X = CF 3SO 3 (-), BF 4 (-); n = 4, 6, 8, 10, 12]. The derivatives with n = 4, 6 exhibit spin transition behavior like in crystalline compounds, whereas those with n = 8, 10, 12 present a spin transition coexisting with the mesomorphic behavior in the room-temperature region. A columnar mesophase has been found for the majority of the metallomesogens, but also a columnar lamellar mesophase was observed for other derivatives. [Fe(C 12-tba) 3](CF 3SO 3) 2 represents a new example of a system where the phase transition directly influences the spin transition of the Fe(II) ions but is not the driving energy of the spin crossover phenomenon. The compounds display drastic changes of color from violet (low-spin state, LS) to white (high-spin state, HS). The compounds are fluid, and it is possible to prepare thin films from them.

  18. Coupled effects of director orientations and boundary conditions on light induced bending of monodomain nematic liquid crystalline polymer plates (United States)

    You, Yue; Xu, Changwei; Ding, Shurong; Huo, Yongzhong


    A photo-chromic liquid crystal polymers (LCPs) is a smart material for large light-activated variation or bending to transfer luminous energy into mechanical energy. We study the light induced behavior by modeling planar and homeotropic nematic network polymer plates. We effectively illustrate some reported experimental outcomes and theoretically predict some possible bending patterns. This paper constructs an understanding between the bending behaviors and interactions among the alignments, aspect ratios and boundary conditions, etc. Our work provides information on optimizing light induced bending in the process of micro-opto-mechanical system (MOMS) design.

  19. Phytantriol and glyceryl monooleate cubic liquid crystalline phases as sustained-release oral drug delivery systems for poorly water-soluble drugs II. In-vivo evaluation. (United States)

    Nguyen, Tri-Hung; Hanley, Tracey; Porter, Christopher J H; Larson, Ian; Boyd, Ben J


    Lipid-based liquid crystals formed from phytantriol (PHY) and glyceryl monooleate (GMO) retain their cubic-phase structure on dilution in physiologically relevant simulated gastrointestinal media, suggesting their potential application as sustained-release drug-delivery systems for poorly water-soluble drugs. In this study the potential of PHY and GMO to serve as sustained-release lipid vehicles for a model poorly-water-soluble drug, cinnarizine, was assessed and compared to that of an aqueous suspension formulation. Small-angle X-ray scattering was used to confirm the nanostructure of the liquid-crystalline matrix in the presence of the selected model drug, cinnarizine. Oral bioavailability studies were conducted in rats, and disposition of lipid and drug in segments of the gastrointestinal tract was determined over time. Differences in the digestibility and stability of formulations under digestion conditions were investigated using an in-vitro lipolysis model. The oral bioavailability of cinnarizine using the PHY formulation was 41%, compared to 19% for the GMO formulation and 6% for an aqueous suspension. The PHY formulation provided a T(max) for cinnarizine of 33 h, with absorption apparent up to 55 h after administration. In contrast, the T(max) for the GMO formulation was only 5 h. The PHY formulation was retained in the stomach for extended periods of time, with 56% of lipid remaining in the stomach after 24 h, in contrast to less than 1% of the GMO formulation after 8 h, suggesting that gastric retention was a key aspect of the prolonged period of absorption, which correlated with the formulations' relative susceptibility to in-vitro lipolysis and degradation. PHY provides a dramatic sustained-release effect for cinnarizine on oral administration, which is linked to gastric retention of the formulation and its ability to resist digestive processing. Poorly digested liquid crystal lipid formulations therefore offer a novel class of sustained

  20. Dynamics of supercooled liquid and plastic crystalline ethanol: Dielectric relaxation and AC nanocalorimetry distinguish structural α- and Debye relaxation processes. (United States)

    Chua, Y Z; Young-Gonzales, A R; Richert, R; Ediger, M D; Schick, C


    Physical vapor deposition has been used to prepare glasses of ethanol. Upon heating, the glasses transformed into the supercooled liquid phase and then crystallized into the plastic crystal phase. The dynamic glass transition of the supercooled liquid is successfully measured by AC nanocalorimetry, and preliminary results for the plastic crystal are obtained. The frequency dependences of these dynamic glass transitions observed by AC nanocalorimetry are in disagreement with conclusions from previously published dielectric spectra of ethanol. Existing dielectric loss spectra have been carefully re-evaluated considering a Debye peak, which is a typical feature in the dielectric loss spectra of monohydroxy alcohols. The re-evaluated dielectric fits reveal a prominent dielectric Debye peak, a smaller and asymmetrically broadened peak, which is identified as the signature of the structural α-relaxation and a Johari-Goldstein secondary relaxation process. This new assignment of the dielectric processes is supported by the observation that the AC nanocalorimetry dynamic glass transition temperature, Tα, coincides with the dielectric structural α-relaxation process rather than the Debye process. The combined results from dielectric spectroscopy and AC nanocalorimetry on the plastic crystal of ethanol suggest the occurrence of a Debye process also in the plastic crystal phase.

  1. Directed Self-Assembly of Colloidal Particles onto Nematic Liquid Crystalline Defects Engineered by Chemically Patterned Surfaces. (United States)

    Li, Xiao; Armas-Pérez, Julio C; Hernández-Ortiz, Juan P; Arges, Christopher G; Liu, Xiaoying; Martínez-González, José A; Ocola, Leonidas E; Bishop, Camille; Xie, Helou; de Pablo, Juan J; Nealey, Paul F


    In exploiting topological defects of liquid crystals as the targeting sites for trapping colloidal objects, previous work has relied on topographic features with uniform anchoring to create defects, achieving limited density and spacing of particles. We report a generalizable strategy to create topological defects on chemically patterned surfaces to assemble particles in precisely defined locations with a tunable interparticle distance at nanoscale dimensions. Informed by experimental observations and numerical simulations that indicate that liquid crystals, confined between a homeotropic-anchoring surface and a surface with lithographically defined planar-anchoring stripes in a homeotropic-anchoring background, display splay-bend deformation, we successfully create pairs of defects and subsequently trap particles with controlled spacing by designing patterns of intersecting stripes aligned at 45° with homeotropic-anchoring gaps at the intersections. Application of electric fields allows for dynamic control of trapped particles. The tunability, responsiveness, and adaptability of this platform provide the opportunities for assembly of colloidal structures toward functional materials.

  2. Convection and evaporation rate of planar liquid films subjected to impulsive superheating (United States)

    Kimball, J. T.; Hermanson, J. C.; Allen, J. S.


    The interfacial stability, convective structure, and evaporation rate of upward-facing, thin liquid films were studied experimentally. Four different working fluids were used. Films initially 5 mm to 100 μm thick were subjected to impulsive superheating. The films resided on a temperature controlled, gold-plated copper surface in a closed, initially degassed test chamber. Superheating was achieved by suddenly dropping the pressure of the saturated pure vapor in the test chamber. The dynamic film thickness was measured at multiple points using ultrasound, and instability wavelength and convective structure information was obtained by schlieren imaging. Considering previous quasi-steady results, the observed convection patterns in many cases suggest an initial, limited penetration of the convection structures into the film. The initial convection patterns and measured evaporation rate in these films are independent of the thermal boundary condition of the substrate. After a sufficiently long time, the convection pattern changes and approaches the previously observed quasi-steady condition.

  3. Subjectivity

    Directory of Open Access Journals (Sweden)

    Jesús Vega Encabo


    Full Text Available In this paper, I claim that subjectivity is a way of being that is constituted through a set of practices in which the self is subject to the dangers of fictionalizing and plotting her life and self-image. I examine some ways of becoming subject through narratives and through theatrical performance before others. Through these practices, a real and active subjectivity is revealed, capable of self-knowledge and self-transformation. 

  4. Ionic self-assembled derivative of tetraphenylethylene: Synthesis, enhanced solid-state emission, liquid crystalline structure and Cu2+ detection ability. (United States)

    Ren, Xiang-Kui; Lu, Lin; Liu, Rui; Jiang, Xu-Qiang; Geng, Lai-Yao; Zheng, Jun-Feng; Feng, Yakai; Chen, Er-Qiang


    A novel tetraphenylethylene complex (ETTC-DOAB) with enhanced solid-state emission was designed and synthesized via ionic self-assembly (ISA) strategy. The aggregation-induced emission property, phase behavior, and supramolecular structure of the complex were characterized by a combination of variety experimental measurements. The experimental results reveal that the ISA complex could self-assemble into ordered helical supramolecular structure with enhanced luminescent property though the ETTC cores possess large conjugation and high rigidity. Due to the prolonged conjugation length, the fluorescence quantum yield of ETTC-DOAB is boosted to 66%. Moreover, it is demonstrated that the assemblies of the ISA complex could be an effective sensor for Cu2+. Owing to the disassembly modulation of ETTC-DOAB aggregations, the fluorescence emission of the assemblies can be selectively and sensitively quenched by Cu2+ with the detection limit as low as 12.6 nM. The enhanced emission efficiency, in combination with the liquid crystallinity and superior sensing performance to Cu2+, make the ETTC-DOAB complex a potential candidate for fabrication of luminescent device and chemosensor for Cu2+ detection. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Lyotropic chiral nematic liquid crystalline aliphatic conjugated polymers based on disubstituted polyacetylene derivatives that exhibit high dissymmetry factors in circularly polarized luminescence. (United States)

    San Jose, Benedict A; Matsushita, Satoshi; Akagi, Kazuo


    We synthesized disubstituted liquid crystalline polyacetylene (diLCPA) derivatives bearing 4-nonyloxy phenyl groups with lyotropic and thermotropic LC behavior. The poly(diphenylacetylene) main chain structure of the diLCPAs and the chirality induced with either chiral moieties or chiral dopants allow the formation of a highly ordered lyotropic N*-LC phase. Circular dichroism (CD) spectra of the diLCPAs imply that one-handed intrachain helical structures are formed in solution, while interchain helical π-stacking between the polymer main chains are formed in cast film and in the N*-LC state. Absorption dissymmetry factors (g(abs)) in the N*-LC state show values on the order of 10(-1). The N*-LC state facilitates the formation of helically π-stacked structures with a high degree of helical ordering of the diLCPA and is indispensable for the generation of circularly polarized luminescence (CPL) with high emission dissymmetry factors (g(em)) on the order of 10(-1). To the best of our knowledge, this is the highest reported value of CPL achieved for aliphatic, conjugated polymers. As an alternative to the thermotropic N*-LC phase, we have found that the lyotropic N*-LC phase of diLCPA could be promising materials possessing CPL functionality for use in next-generation π-conjugated organic optoelectronic devices, displays, and sensors.

  6. Efeito compatibilizante de copolímeros contendo segmentos líquido-cristalinos em misturas com poli(tereftalato de etileno e um poliéster líquido-cristalino termotrópico (TLCP Compatibilizing effect of copolymers with liquid crystalline segments in blends of poly(ethylene terephthalate and a thermotropic liquid crystalline polyester (TLCP

    Directory of Open Access Journals (Sweden)

    Kátia M. Novack


    Full Text Available Uma série de copolímeros com segmentos líquido-cristalinos foram sintetizados por policondensação em solução a alta temperatura e misturados com poli(tereftalato de etileno (PET e um poliéster líquido-cristalino termotrópico (TLCP, previamente sintetizado. Os copolímeros foram utilizados com sucesso como compatibilizantes nas misturas PET/TLCP. As técnicas de caloria diferencial de varredura, análises dinâmico-mecânicas, análises térmicas e microscopia eletrônica (SEM foram utilizadas na caracterização dos polímeros. Foi verificada boa processabilidade e diminuição da velocidade de cristalização das misturas. As micrografias das superfícies fraturadas das amostras, obtidas das análises de SEM, mostraram melhor miscibilidade para as misturas com maior teor de copolímero.A serie of copolyesters with liquid crystalline segments were synthesized by high temperature solution polycondensation and mixed with poly(ethylene terephthalate (PET and a thermotropic liquid crystalline polyester (TLCP, previously synthesized. The copolyesters were successfully applied to compatibilize PET/TLCP blends. The techniques applied to characterize compatibilization were thermal analysis, differential scanning calorimetry, dynamic mechanical analysis and eletron microscopy (SEM. Good processing and depression of crystallization rate were obtained in blends. The SEM micrographs for fractured surface show better miscibility from PET/TLCP blends with higher content of copolymer.

  7. Synthesis and characterization of novel liquid-crystalline azo-dyes bearing two amino-nitro substituted azobenzene units and a well-defined, oligo(ethylene glycol) spacer

    Energy Technology Data Exchange (ETDEWEB)

    Caicedo, Carolina [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, C.P. 04510 Mexico D.F. (Mexico); Rivera, Ernesto, E-mail: [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, C.P. 04510 Mexico D.F. (Mexico); Valdez-Hernandez, Yazmin; Carreon-Castro, Maria del Pilar [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, C.P. 04510 Mexico D.F. (Mexico)


    Highlights: {yields} Novel dyes containing azobenzene and oligo(ethylene glycol) were synthesized. {yields} Absorption spectra of RED-PEG dyes in CHCl{sub 3} showed {lambda}{sub max} = 440-480 nm. {yields} Absorption spectra of RED-PEG dyes in film revealed the formation of H-aggregates. {yields} Their liquid-crystalline behaviour was confirmed by light polarized microscopy. {yields} These liquid-crystalline dyes can form Langmuir films on the air-water interface. - Abstract: Four novel liquid-crystalline azo-dyes bearing two amino-nitro substituted azobenzene units linked by a well-defined oligo(ethylene glycol) spacer (DIRED-PEG series): (E)-N,N'-(2,2'-oxybis(ethane-2,1-diyl))bis(N-methyl-4-((E)-(4-nitrophenyl) diazenyl) benzenamine) (DIRED-PEG-2), (E)-N,N'-(2,2'-(ethane-1,2-diylbis(oxy)) bis(ethane-2,1-diyl)) bis(N-methyl-4-((E)-(4-nitrophenyl) diazenyl) benzenamine) (DIRED-PEG-3), (E)-N,N'-(2,2'-(2,2'-oxybis (ethane-2,1-diyl) bis(oxy)) bis(ethane-2,1-diyl)) bis(N-methyl-4-((E)-(4-nitrophenyl) diazenyl) benzenamine) (DIRED-PEG-4) and N1,N17-dimethyl-N1,N17-bis (4-((E)-(4-nitrophenyl) diazenyl) phenyl)-3,6,9,12,15-pentaoxaheptadecane-1,17-diamine (DIRED-PEG-6) have been synthesized. These dyes were fully characterized by FTIR, {sup 1}H and {sup 13}C NMR spectroscopies, and their thermal and optical properties were studied. Besides, the liquid-crystalline behaviour of these compounds was monitored in function of the temperature by light polarized microscopy. Finally, Langmuir films were prepared with these dyes.

  8. Self-pressurization of a flightweight liquid hydrogen storage tank subjected to low heat flux (United States)

    Hasan, M. M.; Lin, C. S.; Vandresar, N. T.


    Results are presented for an experimental investigation of self-pressurization and thermal stratification of a 4.89 cu m liquid hydrogen (LH2) storage tank subjected to low heat flux (0.35, 2.0, and 3.5 W/sq m) under normal gravity conditions. Tests were performed at fill levels of 83 to 84 percent (by volume). The LH2 tank was representative of future spacecraft tankage, having a low mass-to-volume ratio and high performance multilayer thermal insulation. Results show that the pressure rise rate and thermal stratification increase with increasing heat flux. At the lowest heat flux, the pressure rise rate is comparable to the homogenous rate, while at the highest heat flux, the rate is more than three times the homogeneous rate. It was found that initial conditions have a significant impact on the initial pressure rise rate. The quasi-steady pressure rise rates are nearly independent of the initial condition after an initial transient period has passed.

  9. Simultaneous estimation of liquid and solid gastric emptying using radiolabelled egg and water in supine normal subjects. (United States)

    Kris, M G; Yeh, S D; Gralla, R J; Young, C W


    To develop an additional method for the measurement of gastric emptying in supine subjects, 10 normal subjects were given a test meal containing 99Tc-labelled scrambled egg as the "solid" phase marker and 111In in tapwater as the marker for the "liquid" phase. The mean time for emptying 50% of the "solid" phase (t1/2) was 85 min and 29 min for the "liquid" phase. Three individuals were restudied with a mean difference between the two determinations of 10.8% for the "solid" phase and 6.5% for the "liquid" phase. Twenty-six additional studies attempted have been successfully completed in symptomatic patients with advanced cancer. This method provides a simple and reproducible procedure for the determination of gastric emptying that yields results similar to those reported for other test meals and can be used in debilitated patients.

  10. Synthesis and Characterization of Ferroelectric Liquid Crystalline Organosiloxanes Containing 4-(4-undecanyloxy bi-phenyl-1-carboxyloxyphenyl (2S,3S-2-chloro-3-methylvalerate and 4-(4-undecanyloxybenzoyloxybiphenyl (2S,3S-2-chloro-3-methylvalerate

    Directory of Open Access Journals (Sweden)

    Chih-Hung Lin


    Full Text Available A series of new organosiloxane ferroelectric liquid crystalline (FLC materials have been synthesized, and their mesomorphic and physical properties have been characterized. Four new disiloxanes and trisiloxanes, containing biphenyl 4-hydroxybenzoate and phenyl 4-hydroxybiphenylcarboxylate as mesogenic units and eleven methylene unit as spacers and (2S,3S-2-chloro-3-methylvalerate unit as chiral end groups. The molecule, using three phenyl ring as a mesogenic unit, formulates much wider liquid crystalline phase temperature ranges than that of a two phenyl ring unit. The phenyl arrangement differences of mesogenic unit result in the greater differences of the liquid crystal phase formation. The siloxane molecule induction is helpful to the more regular smectic phase formation and smectic phase stabilization, such as chiral SC (SC* and SB phases. The siloxane molecule is helpful to reduce the phase transition temperature and broaden the liquid crystal temperature range of the SC* phase and, simultaneously, it will not induce chain crystallization phenomenon and dilute the Ps value. The synthesis and characterization of the new FLCs materials, which exhibit a room temperature SC* phase and higher spontaneous polarization are presented.

  11. Research into energy absorption of liquid cabin subjected to close-range explosion

    Directory of Open Access Journals (Sweden)

    LI Siyu


    Full Text Available In order to study the energy absorption of different parts of a liquid cabin under a close-range explosion, a fluid-structure coupling model is built on the basis of experiments, and the deformation of the bulkhead and energy absorption ratio of different parts of the liquid cabin are analyzed, in which the influence of the water, bulkhead thickness ratio and water thickness are also discussed. The results show that the existence of a liquid medium can change the energy absorption model of a cabin. The total energy absorption is mainly affected by the front bulkhead thickness and water thickness, and alterations to the bulkhead thickness ratio or water thickness can also affect the deformation model of the bulkhead and energy absorption ratio of different parts of the cabin. A logical explanation of the energy absorption mechanisms of the liquid cabin is proposed, and some useful suggestions for designs are given.

  12. Optimum Parameters of a Tuned Liquid Column Damper in a Wind Turbine Subject to Stochastic Load (United States)

    Alkmim, M. H.; de Morais, M. V. G.; Fabro, A. T.


    Parameter optimization for tuned liquid column dampers (TLCD), a class of passive structural control, have been previously proposed in the literature for reducing vibration in wind turbines, and several other applications. However, most of the available work consider the wind excitation as either a deterministic harmonic load or random load with white noise spectra. In this paper, a global direct search optimization algorithm to reduce vibration of a tuned liquid column damper (TLCD), a class of passive structural control device, is presented. The objective is to find optimized parameters for the TLCD under stochastic load from different wind power spectral density. A verification is made considering the analytical solution of undamped primary system under white noise excitation by comparing with result from the literature. Finally, it is shown that different wind profiles can significantly affect the optimum TLCD parameters.

  13. Water liquid-vapor interface subjected to various electric fields: A molecular dynamics study (United States)

    Nikzad, Mohammadreza; Azimian, Ahmad Reza; Rezaei, Majid; Nikzad, Safoora


    Investigation of the effects of E-fields on the liquid-vapor interface is essential for the study of floating water bridge and wetting phenomena. The present study employs the molecular dynamics method to investigate the effects of parallel and perpendicular E-fields on the water liquid-vapor interface. For this purpose, density distribution, number of hydrogen bonds, molecular orientation, and surface tension are examined to gain a better understanding of the interface structure. Results indicate enhancements in parallel E-field decrease the interface width and number of hydrogen bonds, while the opposite holds true in the case of perpendicular E-fields. Moreover, perpendicular fields disturb the water structure at the interface. Given that water molecules tend to be parallel to the interface plane, it is observed that perpendicular E-fields fail to realign water molecules in the field direction while the parallel ones easily do so. It is also shown that surface tension rises with increasing strength of parallel E-fields, while it reduces in the case of perpendicular E-fields. Enhancement of surface tension in the parallel field direction demonstrates how the floating water bridge forms between the beakers. Finally, it is found that application of external E-fields to the liquid-vapor interface does not lead to uniform changes in surface tension and that the liquid-vapor interfacial tension term in Young's equation should be calculated near the triple-line of the droplet. This is attributed to the multi-directional nature of the droplet surface, indicating that no constant value can be assigned to a droplet's surface tension in the presence of large electric fields.

  14. An experimental study of the behavior of liquid jets subjected to thermodynamic subcritical and supercritical conditions (United States)

    Spegar, Timothy Daniel

    As pressures and temperatures have risen in internal combustion engines, liquid fuel injection into an environment exceeding the critical pressure and temperature of the fuel is routine. If the fuel/oxidizer mixture reaches critical conditions, surface tension vanishes while the vapor/liquid density ratio approaches unity, altering the mixing behavior of the fuel and oxidizer from the well-studied behavior of jets injected into environments of more modest pressures and temperatures. To elucidate these issues, an experimental study of n-pentane jet breakup in high pressure and high temperature nitrogen environments was performed. Specifically, n-pentane at 20°C was injected transversely into nitrogen through a plain orifice atomizer at velocities varying from 1.0 m/sec to 6.0 m/sec. The nitrogen temperature and pressure were varied from 20°C to 300°C and 100 psig to 1500 psig, respectively. The experiments were carried out in an optically accessible test chamber and two-dimensional spontaneous Raman imaging was employed to attempt to quantify the degree of jet vaporization. An analysis of the jets' breakup mechanism, continuous length, drag coefficient and wake fuel concentration was conducted to determine if jet behavior at extreme pressures and temperatures could be explained by the characteristic decrease in surface tension and increase in gas/liquid density ratio as the critical point is reached. Though not all results could be explained by the appropriate changes in surface tension and the gas/liquid density ratio, jet behavior at ambient conditions in excess of the liquid critical point was observed to differ from behavior typical of jets injected at relatively low pressures. Furthermore, little variation in wake intensity was seen, but this is conceivable considering the inherent difficulties in spontaneous Raman scattering, most notably, its intrinsic weakness. Suggestions for improving the results of the Raman measurements employed in this investigation

  15. Determination of skin temperature under a comfort-controlled liquid-cooled garment in exercising subjects (United States)

    Santamaria, L. J.


    The physiological responses of exercising subjects were investigated under conditions in which the temperature of the coolant water was varied according to the subjective state of thermal comfort. Conditioning water was maintained at a constant flow rate of 240 lb/hr and at a temperature controllable within the range of 45 to 90 F. In addition to skin temperatures, rectal temperature and heart rate were monitored in the course of each trial. Total and evaporative weight losses were determined by measurements before and after each test. The levels on metabolic loading, measured indirectly on the basis of O2 consumption in the course of treadmill activity, ranged from the resting state to 2000 BTU/hr at increments of about 400 BTU. Under the experimental conditions, six volunteer subjects established a level of thermal comfort, as sensed subjectively, by controlling inlet water within the available range of temperature.

  16. The liquid concept in Zygmunt Bauman: contemporaneity and production of subjectivity

    Directory of Open Access Journals (Sweden)

    Rafael Bianchi Silva


    Full Text Available The purpose of this article is discuss the concept of liquid from the work of Zygmunt Bauman. Therefore, a debate was held from three analysis axes: the order, uncertainty and dissatisfaction. It’s seen a new man setting in this liquefied scenario, marked by the modification and extension of the notion of time and space electing the consumption as society parameter in view of the loss of reference of social institutions while organizing and guiding sphere of life, which challenges the individual to survive in the middle of the instability that all of this represent. Thus, the term employee seeks to demonstrate the existence of a new relationship between man and the world, marked by identity instability, the weakening link and establishing relationships mediated by sense of fear. It concludes that the concept investigated is not configured as a complete breakdown of the assumptions of modernity, but rather, its radicalization.

  17. Esophageal contractions, bolus transit and perception of transit after swallows of liquid and solid boluses in normal subjects

    Directory of Open Access Journals (Sweden)

    Juciléia Dalmazo


    Full Text Available CONTEXT: Esophageal dysphagia is the sensation that the ingested material has a slow transit or blockage in its normal passage to the stomach. It is not always associated with motility or transit alterations. OBJECTIVES: To evaluate in normal volunteers the possibility of perception of bolus transit through the esophagus after swallows of liquid and solid boluses, the differences in esophageal contraction and transit with these boluses, and the association of transit perception with alteration of esophageal contraction and/or transit. METHODS: The investigation included 11 asymptomatic volunteers, 4 men and 7 women aged 19-58 years. The subjects were evaluated in the sitting position. They performed swallows of the same volume of liquid (isotonic drink and solid (macaroni boluses in a random order and in duplicate. After each swallow they were asked about the sensation of bolus passage through the esophagus. Contractions and transit were evaluated simultaneously by solid state manometry and impedance. RESULTS: Perception of bolus transit occurred only with the solid bolus. The amplitude and area under the curve of contractions were higher with swallows of the solid bolus than with swallows of the liquid bolus. The difference was more evident in swallows with no perception of transit (n = 12 than in swallows with perception (n = 10. The total bolus transit time was longer for the solid bolus than for the liquid bolus only with swallows followed by no perception of transit. CONCLUSION: The results suggest that the perception of esophageal transit may be the consequence of inadequate adaptation of esophageal transit and contraction to the characteristics of the swallowed bolus.

  18. The determination of the phase transition temperatures of a semifluorinated liquid crystalline biphenyl ester by impedance spectroscopy as an alternative method

    Energy Technology Data Exchange (ETDEWEB)

    Yıldız, Alptekin [Istanbul Technical University, Department of Physics Engineering, Maslak, 34469 Istanbul (Turkey); Yildiz Technical University, Department of Physics, 34220 Istanbul (Turkey); Canli, Nimet Yilmaz, E-mail: [Yildiz Technical University, Department of Physics, 34220 Istanbul (Turkey); Karanlık, Gürkan; Ocak, Hale [Yildiz Technical University, Department of Chemistry, 34220 Istanbul (Turkey); Okutan, Mustafa [Yildiz Technical University, Department of Physics, 34220 Istanbul (Turkey); Eran, Belkız Bilgin [Yildiz Technical University, Department of Chemistry, 34220 Istanbul (Turkey)


    Dielectric spectroscopy (DS) is a very powerful and important for better understanding of the molecular dynamics and relaxation phenomena in liquid crystals. The dielectric and impedance characteristics Ethyl 4-(7,7,8,8,9,9,10,10,10-nonafluorodecyloxy)biphenyl-4′-carboxylate (ENBC) liquid crystal have been analyzed over the frequency range of 100 Hz to MHz in the temperature region from room temperature to 180 °C. The compound ENBC shows enantiotropic a smectic mesophase in a wide temperature range. The phase transition temperatures T (°C) of the liquid crystal ENBC, which were characterized by Differential Scanning Calorimetry (DSC), have been verified by the dielectric measurements and conductivity mechanisms of the ENBC. The activation energies for some selected angular frequencies have also been calculated.

  19. Combination of benzoyl peroxide 5% gel with liquid cleanser and moisturizer SPF 30 in acne treatment results in high levels of subject satisfaction, good adherence and favorable tolerability. (United States)

    Kim, Mi-Ran; Kerrouche, Nabil


    Skin care products (cleansers and moisturizers) to complement benzoyl peroxide (BPO) in the treatment of acne may improve treatment tolerability and adherence. Evaluate subject satisfaction after use of BPO 5% gel in combination with liquid cleanser and moisturizer SPF 30. Open-label study including subjects aged ≥12 years with mild-to-moderate facial acne; Identifier: NCT02589405. Once daily BPO 5% gel, twice daily liquid cleanser and once daily moisturizer SPF 30 were applied for 12 weeks. Assessments included a subject satisfaction questionnaire, investigator global assessment of improvement, lesion counts, the presence of Propionibacterium acnes, and safety. Fifty subjects were enrolled. Most subjects were overall satisfied with the three-part regimen (87%) and felt better about themselves (94%). Subjects indicated the skin care products helped prepare the skin for treatment (85%), relieve itchy skin (81%) and reduce irritation (87%). Most subjects considered that the liquid cleanser (80%) and moisturizer SPF 30 (84%) were a necessary part of acne treatment. BPO reduced P. acnes load by 89% at week 1. The treatment was well tolerated. The combination of BPO 5% gel with liquid cleanser and moisturizer SPF 30 resulted in high levels of subject satisfaction, good tolerability and treatment adherence.

  20. Chemical preparation of crystalline, nonmolecular solids, including solution-liquid-solid (SLS) growth of semiconductor fibers and varied routes to nanocrystalline molybdenum disilicide (United States)

    Trentler, Timothy John

    New methods for the preparation of crystalline, nonmolecular solids under milder conditions and/or with control of crystallite size or morphology were developed in two separate projects. In one project, polycrystalline 13-15 semiconductor fibers (dimensions 10-100 nm x 50-1000 nm) were grown by solution-based chemical methods. Crystal precursor species of the general formula (Rsb{x}InEHsb{x}rbracksb{n}, where E is a pnictide and R is an alkyl group, were prepared by the phosphinolysis or arsinolysis of alkylindanes in aromatic solvents. Thermal decomposition of these precursors in solution, which was catalyzed by various protic reagents (MeOH, PhSH, Etsb2NH, or PhCOsb2H), resulted in crystalline InE when In metal was present in the form of submicron droplets dispersed in the solvent. Crystallization was determined to occur (at the lowest temperatures reported for 13-15 semiconductors, halides by NaK alloy in an ultrasonically agitated hydrocarbon solvent followed by thermal processing (900sp°C) under vacuum to eliminate byproduct salts. MoSisb2 crystallites averaging 20-50 nm were obtained. Solvent degradation during this process resulted in the incorporation of substantial carbonaceous impurity (believed to be SiC) in these products. To eliminate the carbon, similar solventless reductions (without ultrasound) were conducted in molten magnesium, but average particle sizes have not been refined into the nanometer regime (currently 100-200 nm). The second method was the reaction of MoClsb3 and Si in the solid state. These reactants underwent an ignition at approximately 500sp°C that resulted in the evolution of SiClsb4 and the formation of MoSisb2 crystallites. Crystallite size was dependent on reaction scale and was only nanocrystalline for very small scales. Addition of an inert salt to the reaction mixture, however, moderated the exothermic process and allowed for the preparation of nanocrystalline product (˜50 nm). Some of the nanocrystalline MoSisb2 powders

  1. Crystalline and Crystalline International Disposal Activities

    Energy Technology Data Exchange (ETDEWEB)

    Viswanathan, Hari S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chu, Shaoping [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Reimus, Paul William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Makedonska, Nataliia [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hyman, Jeffrey De' Haven [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Karra, Satish [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dittrich, Timothy M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)


    This report presents the results of work conducted between September 2014 and July 2015 at Los Alamos National Laboratory in the crystalline disposal and crystalline international disposal work packages of the Used Fuel Disposition Campaign (UFDC) for DOE-NE’s Fuel Cycle Research and Development program.

  2. Feasibility of measuring gastric emptying time, with a wireless motility device, after subjects consume fiber-matched liquid and solid breakfasts. (United States)

    Willis, Holly J; Thomas, William; Willis, David J; Slavin, Joanne L


    To explore the feasibility and sensitivity of a new technology for measuring gastric emptying time (GET) in appetite research, and also to compare appetite after subjects consumed macronutrient- and fiber-matched liquid and solid meals. Fourteen women (BMI of 21.2 ± 0.3) participated in this randomized, crossover study. On two separate days, fasted subjects consumed liquid (fruit juices and skim milk) and solid (oatmeal, blueberries, and apples) breakfasts. Both meals had 10 g of fiber and 410 kcal. GET was assessed with the SmartPill GI Motility System®, appetite was assessed with visual analog scales, and food intake was measured at lunch. Despite the same amount of fiber, GET was about 1h longer after the oatmeal than after the liquids. Subjects were less hungry after the oatmeal than after the liquids. Satisfaction and fullness were marginally improved with the oatmeal compared to the liquids. There was a negative association between GET and hunger. Lunchtime food and beverage intake did not differ between treatments. The SmartPill appears feasible and sensitive in appetite research, but has limitations. A solid meal with naturally occurring fiber from oatmeal and whole fruits increased GET and decreased hunger more than a liquid meal with added fiber. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Structural and dynamical properties of the Cu{sub 46}Zr{sub 54} alloy in crystalline, amorphous and liquid state: A molecular dynamic study

    Energy Technology Data Exchange (ETDEWEB)

    Valencia-Balvin, Camilo, E-mail: [Instituto de Fisica, Universidad de Antioquia, A.A. 1226 Medellin (Colombia); ITM Institucion Universitaria, A.A 54959 Medellin (Colombia); Loyola, Claudia [Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago (Chile); Osorio-Guillen, Jorge [Instituto de Fisica, Universidad de Antioquia, A.A. 1226 Medellin (Colombia); Gutierrez, Gonzalo [Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago (Chile)


    Molecular dynamics simulations for the crystal, amorphous and liquid Cu{sub 46}Zr{sub 54} alloy were carried out on a system with up to 2000 particles, using a pairwise potential of the Rosato-Guillope-Legrand type. All simulations were done in the microcanonical ensemble, for a initial density of 5.76 g/cm{sup 3}, at different temperatures. A detailed analysis has been made by means of the pair-correlation function, coordination number, angle distribution, diffusion coefficient and vibrational density of states. We compared the main peaks of the amorphous phase with experimental data, obtaining a good agreement. The analysis of coordination number for the amorphous phase shows that the main building block of this phase are distorted icosahedron.

  4. Lipase inhibition and hormonal status, body composition and gastrointestinal processing of a liquid high-fat mixed meal in moderately obese subjects.

    NARCIS (Netherlands)

    Drent, M.L.; Popp-Snijders, C.; Adèr, H.J.; Jansen, J.B.M.J.; van der Veen, E.A.


    DRENT, MADELEINE L, CORRIE POPP‐SNIJDERS, HERMAN J ADER, JAN BMJ JANSEN AND EDUARD A VAN DER VEEN. Lipase inhibition and hormonal status, body composition and gastrointestinal processing of a liquid high‐fat mixed meal in moderately obese subjects. Obes Res. The effect of Orlistat, a lipase

  5. Crystalline and Crystalline International Disposal Activities

    Energy Technology Data Exchange (ETDEWEB)

    Viswanathan, Hari S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chu, Shaoping [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dittrich, Timothy M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hyman, Jeffrey De' Haven [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Karra, Satish [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Makedonska, Nataliia [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Reimus, Paul William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)


    This report presents the results of work conducted between September 2015 and July 2016 at Los Alamos National Laboratory in the crystalline disposal and crystalline international disposal work packages of the Used Fuel Disposition Campaign (UFDC) for DOE-NE’s Fuel Cycle Research and Development program. Los Alamos focused on two main activities during this period: Discrete fracture network (DFN) modeling to describe flow and radionuclide transport in complex fracture networks that are typical of crystalline rock environments, and a comprehensive interpretation of three different colloid-facilitated radionuclide transport experiments conducted in a fractured granodiorite at the Grimsel Test Site in Switzerland between 2002 and 2013. Chapter 1 presents the results of the DFN work and is divided into three main sections: (1) we show results of our recent study on the correlation between fracture size and fracture transmissivity (2) we present an analysis and visualization prototype using the concept of a flow topology graph for characterization of discrete fracture networks, and (3) we describe the Crystalline International work in support of the Swedish Task Force. Chapter 2 presents interpretation of the colloidfacilitated radionuclide transport experiments in the crystalline rock at the Grimsel Test Site.

  6. Crystalline Silica Primer (United States)



    Crystalline silica is the scientific name for a group of minerals composed of silicon and oxygen. The term crystalline refers to the fact that the oxygen and silicon atoms are arranged in a threedimensional repeating pattern. This group of minerals has shaped human history since the beginning of civilization. From the sand used for making glass to the piezoelectric quartz crystals used in advanced communication systems, crystalline silica has been a part of our technological development. Crystalline silica's pervasiveness in our technology is matched only by its abundance in nature. It's found in samples from every geologic era and from every location around the globe. Scientists have known for decades that prolonged and excessive exposure to crystalline silica dust in mining environments can cause silicosis, a noncancerous lung disease. During the 1980's, studies were conducted that suggested that crystalline silica also was a carcinogen. As a result of these findings, crystalline silica has been regulated under the Occupational Safety and Health Administration's (OSHA) Hazard Communication Standard (HCS). Under HCS, OSHAregulated businesses that use materials containing 0.1% or more crystalline silica must follow Federal guidelines concerning hazard communication and worker training. Although the HCS does not require that samples be analyzed for crystalline silica, mineral suppliers or OSHAregulated

  7. Crystalline boron nitride aerogels (United States)

    Zettl, Alexander K.; Rousseas, Michael; Goldstein, Anna P.; Mickelson, William; Worsley, Marcus A.; Woo, Leta


    This disclosure provides methods and materials related to boron nitride aerogels. In one aspect, a material comprises an aerogel comprising boron nitride. The boron nitride has an ordered crystalline structure. The ordered crystalline structure may include atomic layers of hexagonal boron nitride lying on top of one another, with atoms contained in a first layer being superimposed on atoms contained in a second layer.

  8. Electronic cigarette user plasma nicotine concentration, puff topography, heart rate, and subjective effects: Influence of liquid nicotine concentration and user experience. (United States)

    Hiler, Marzena; Breland, Alison; Spindle, Tory; Maloney, Sarah; Lipato, Thokozeni; Karaoghlanian, Nareg; Shihadeh, Alan; Lopez, Alexa; Ramôa, Carolina; Eissenberg, Thomas


    Electronic cigarette (ECIG) nicotine delivery and other effects may depend on liquid nicotine concentration and user experience. This study is the first to systematically examine the influence of ECIG liquid nicotine concentration and user experience on nicotine delivery, heart rate, puff topography, and subjective effects. Thirty-three ECIG-experienced individuals and 31 ECIG-naïve cigarette smokers completed 4 laboratory conditions consisting of 2, 10-puff bouts (30-sec interpuff interval) with a 3.3-V ECIG battery attached to a 1.5-Ω "cartomizer" (7.3 W) filled with 1 ml ECIG liquid. Conditions differed by liquid nicotine concentration: 0, 8, 18, or 36 mg/ml. Participants' plasma nicotine concentration was directly related to liquid nicotine concentration and dependent on user experience, with significantly higher mean plasma nicotine increases observed in ECIG-experienced individuals relative to ECIG-naïve smokers in each active nicotine condition. When using 36 mg/ml, mean plasma nicotine increase for ECIG-experienced individuals was 17.9 ng/ml (SD = 17.2) and 6.9 (SD = 7.1; p users: collapsed across condition, mean puff duration was 5.6 sec (SD = 3.0) for ECIG-experienced and 2.9 (SD = 1.5) for ECIG-naïve individuals. ECIG use also suppressed nicotine/tobacco abstinence symptoms in both groups; the magnitude of abstinence symptom suppression depended on liquid nicotine concentration and user experience. These and other recent results suggest that policies intended to limit ECIG nicotine delivery will need to account for factors in addition to liquid nicotine concentration (e.g., device power and user behavior). (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  9. Liquid crystalline networks for electroluminescent displays

    CERN Document Server

    Contoret, A E A


    This work presents the first low molar mass organic electroluminescent (EL) material to form a nematic glass and then emit plane-polarised light from the vitrified state on application of an electric field. Photocrosslinkable molecules are also discussed which form insoluble films on illumination with ultra-violet light. This approach combines the ease of deposition of small molecules with the robustness and stability of polymers, allowing simple fabrication of multi-layer EL devices and photo-patterning. A range of conjugated low molar-mass molecules are considered, containing the anthracene, perylene and fluorene cores, with the aims of producing a general recipe for efficient EL, based on ordered, stable nematics at room temperature. Many physical properties are compared and molecular mechanics modeling is used to represent molecular geometries. An acrylate and several diene photo-polymerisable derivatives of the fluorenes undergo photo-crosslinking. Infrared and photoluminescence spectroscopy is used to e...

  10. Synthesis and characterization of thermotropic liquid crystalline ...

    Indian Academy of Sciences (India)

    Abstract. Non-symmetrical and linear dyad-based mesogens were synthesised containing imine or ester bridging group. In the present work, due to the absence of branching in diamine-based mesogen, the structure has—rigidity inversely imine/ester bridging groups between two benzene rings imparts—flexible property to ...

  11. Liquid crystalline critical dynamics in decylammonium chloride

    CERN Document Server

    Lee, K W; Lee, C E; Kang, K H; Rhee, C; Kang, J K


    Collective chain dynamics and phase transitions in a model biomembrane, decylammonium chloride (C sub 1 sub 0 H sub 2 sub 1 NH sub 3 Cl), were studied by means of proton nuclear magnetic resonance. Our measurements sensitively reflect the critical dynamics associated with the smectic C to smectic A transition of the lipid bilayer.

  12. Triamterene crystalline nephropathy. (United States)

    Nasr, Samih H; Milliner, Dawn S; Wooldridge, Thomas D; Sethi, Sanjeev


    Medications can cause a tubulointerstitial insult leading to acute kidney injury through multiple mechanisms. Acute tubular injury, a dose-dependent process, occurs due to direct toxicity on tubular cells. Acute interstitial nephritis characterized by interstitial inflammation and tubulitis develops from drugs that incite an allergic reaction. Other less common mechanisms include osmotic nephrosis and crystalline nephropathy. The latter complication is rare but has been associated with several drugs, such as sulfadiazine, indinavir, methotrexate, and ciprofloxacin. Triamterene crystalline nephropathy has been reported only rarely, and its histologic characteristics are not well characterized. We report 2 cases of triamterene crystalline nephropathy, one of which initially was misdiagnosed as 2,8-dihydroxyadenine crystalline nephropathy. Copyright © 2013 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

  13. What Is Crystalline Silica? (United States)

    ... carcinogen. Additionally, breathing crystalline silica dust can cause silicosis , which in severe cases can be disabling, or ... take in oxygen. There is no cure for silicosis. Since silicosis affects lung function, it makes one ...

  14. Topological crystalline insulators in transition metal oxides. (United States)

    Kargarian, Mehdi; Fiete, Gregory A


    Topological crystalline insulators possess electronic states protected by crystal symmetries, rather than time-reversal symmetry. We show that the transition metal oxides with heavy transition metals are able to support nontrivial band topology resulting from mirror symmetry of the lattice. As an example, we consider pyrochlore oxides of the form A2M2O7. As a function of spin-orbit coupling strength, we find two Z2 topological insulator phases can be distinguished from each other by their mirror Chern numbers, indicating a different topological crystalline insulators. We also derive an effective k·p Hamiltonian, similar to the model introduced for Pb(1-x)Sn(x)Te, and discuss the effect of an on-site Hubbard interaction on the topological crystalline insulator phase using slave-rotor mean-field theory, which predicts new classes of topological quantum spin liquids.

  15. The human crystallin gene families

    Directory of Open Access Journals (Sweden)

    Wistow Graeme


    Full Text Available Abstract Crystallins are the abundant, long-lived proteins of the eye lens. The major human crystallins belong to two different superfamilies: the small heat-shock proteins (α-crystallins and the βγ-crystallins. During evolution, other proteins have sometimes been recruited as crystallins to modify the properties of the lens. In the developing human lens, the enzyme betaine-homocysteine methyltransferase serves such a role. Evolutionary modification has also resulted in loss of expression of some human crystallin genes or of specific splice forms. Crystallin organization is essential for lens transparency and mutations; even minor changes to surface residues can cause cataract and loss of vision.

  16. Consumption of a liquid high-fat meal increases triglycerides but decreases high-density lipoprotein cholesterol in abdominally obese subjects with high postprandial insulin resistance. (United States)

    Wang, Feng; Lu, Huixia; Liu, Fukang; Cai, Huizhen; Xia, Hui; Guo, Fei; Xie, Yulan; Huang, Guiling; Miao, Miao; Shu, Guofang; Sun, Guiju


    Abdominal obesity is associated with an increased risk of insulin resistance, which may be a potential contributor to dyslipidemia. However, the relationship between postprandial insulin resistance and lipid metabolism in abdominally obese subjects remains unknown. We hypothesized that postprandial dyslipidemia would be exaggerated in abdominally obese subjects with high postprandial insulin resistance. To test this hypothesis, serum glucose, insulin, triglycerides, total cholesterol, high-density lipoprotein cholesterol, and apolipoprotein B were measured at baseline and postprandial state at 0.5, 1, 2, 4, 6, and 8 hours after a liquid high-fat meal in non-abdominally obese controls (n=44) and abdominally obese subjects with low (AO-LPIR, n=40), middle (n=40), and high postprandial insulin resistance (AO-HPIR, n=40) based on the tertiles ratio of the insulin to glucose areas under the curve (AUC). Their serum adipokines were tested at baseline only. Fasting serum leptin was higher (Pdensity lipoprotein cholesterol AUC was lower (P<.05), in AO-HPIR than those in AO-LPIR and controls. Postprandial AUCs for total cholesterol and apolipoprotein B were similar in abdominally obese subjects with different degrees of postprandial insulin resistance and controls. The present study indicated that the higher degree of postprandial insulin resistance, the more adverse lipid profiles in abdominally obese subjects, which provides insight into opportunity for screening in health. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Thermodynamics of Crystalline States

    CERN Document Server

    Fujimoto, Minoru


    Thermodynamics is a well-established discipline of physics for properties of matter in thermal equilibrium surroundings. Applying to crystals, however, the laws encounter undefined properties of crystal lattices, which therefore need to be determined for a clear and well-defined description of crystalline states. Thermodynamics of Crystalline States explores the roles played by order variables and dynamic lattices in crystals in a wholly new way. This book is divided into three parts. The book begins by clarifying basic concepts for stable crystals. Next, binary phase transitions are discussed to study collective motion of order variables, as described mostly as classical phenomena. In the third part, the multi-electron system is discussed theoretically, as a quantum-mechanical example, for the superconducting state in metallic crystals. Throughout the book, the role played by the lattice is emphasized and examined in-depth. Thermodynamics of Crystalline States is an introductory treatise and textbook on meso...


    NARCIS (Netherlands)



    The invention relates to a novel process for making compositions comprising a polyamid, water and a salt, having reduced crystallinity, wherein the process comprising the steps of: a. mixing the polyamide, water and a salt b. heating the mixture to a temperature above 100°C in a range between 120°C

  19. Artificial crystalline lens

    NARCIS (Netherlands)

    Norrby, S.; Koopmans, S.; Terwee, T.


    Replacement of the crystalline lens with a synthetic soft material (ACL) has been shown to produce 3 to 5 D of accommodation following pharmacologic stimulation in primates for up to 1 year postoperatively. The eyes were relatively clear, suggesting that an injectable synthetic lens is a feasible

  20. Thermodynamics of Crystalline States

    CERN Document Server

    Fujimoto, Minoru


    Thermodynamics is a well-established discipline of physics for properties of matter in thermal equilibrium with the surroundings. Applying to crystals, however, the laws encounter undefined properties of crystal lattice, which therefore need to be determined for a clear and well-defined description of crystalline states. Thermodynamics of Crystalline States explores the roles played by order variables and dynamic lattices in crystals in a wholly new way. The book begins by clarifying basic concepts for stable crystals. Next, binary phase transitions are discussed to study collective motion of order variables, as described mostly as classical phenomena. New to this edition is the examination of magnetic crystals, where magnetic symmetry is essential for magnetic phase transitions. The multi-electron system is also discussed  theoretically, as a quantum-mechanical example, for superconductivity in metallic crystals. Throughout the book, the role played by the lattice is emphasized and studied in-depth. Thermod...

  1. Uveitic crystalline maculopathy. (United States)

    Or, Chris; Kirker, Andrew W; Forooghian, Farzin


    The purpose of this case report is to present a novel cause of crystalline maculopathy. A 52-year-old Japanese female presented with a 4-month history of decreased vision in the left eye. Best corrected visual acuity in the left eye was 20/40. Dilated fundus examination of the right eye was unremarkable, but that of the left eye demonstrated foveal yellow-green intraretinal crystals and mild vitritis. Optical coherence tomography of the left eye revealed small intraretinal fluid cysts and intraretinal crystals. Ultra-widefield fluorescein angiography was normal in the right eye, but that of the left eye demonstrated features of intermediate uveitis. There was no history or findings to suggest any cause for the crystals other than the uveitis. We propose that this may represent a novel category of crystalline retinopathy, termed uveitic crystalline maculopathy. We hypothesize that breakdown of the blood-retinal barrier as seen in uveitis may contribute to the deposition of crystals in the macula, although the precise composition of the crystals is unknown.

  2. West African crystalline maculopathy. (United States)

    Browning, David J


    To report new observations in West African crystalline maculopathy. Retrospective, observational case series. Three patients drawn from a private retina practice. Review of clinical charts and photographic studies. Distribution of intraretinal crystals and changes after laser photocoagulation, and history of ingesting foods typical in a West African diet but atypical for an American diet. All patients were older than 50 years, had diabetic retinopathy, ate green vegetables not found in American diets, and showed no deleterious effects of the crystals. Kola nut ingestion in 2 patients was remote and sparse, and was unknown in a third patient. The first 2 affected patients originating outside the Ibo tribe of Nigeria are reported. The pattern of retinal crystals can be changed, and the quantity of crystals reduced, by laser photocoagulation of associated diabetic retinopathy. West African crystalline retinopathy is distinguishable from other causes of crystalline retinopathy. It may reflect a component of the West African diet, seems to have diabetic retinopathy as a promoting factor via breakdown of the blood-retina barrier, and can be modified by laser photocoagulation of diabetic retinopathy. Increased awareness of the condition will allow physicians seeing West African immigrants to make the diagnosis and treat the patients appropriately.

  3. Amplification of chirality in liquid crystals

    NARCIS (Netherlands)

    Eelkema, Rienk; Feringa, Ben L.


    The amplification of molecular chirality by liquid crystalline systems is widely applied in investigations towards enantioselective solvent - solute interactions, chiral supramolecular assemblies, smart materials, and the development of liquid crystal displays. Here we present an overview of recent

  4. Mesomorphous versus traces of crystallinity: The itraconazole example

    Energy Technology Data Exchange (ETDEWEB)

    Atassi, Faraj, E-mail:; Behme, Robert J.; Patel, Phenil J.


    Highlights: • Characterizing partially disordered pharmaceuticals is very challenging due to the fact that more than one discrete disordered phase can be present. • Dynamic mechanical analysis and dielectric analysis are extremely helpful in characterizing pharmaceutical mesophases (liquid crystals). • Thermotropic pharmaceutical mesophases, often mistaken as amorphous or partially crystalline, can show different phases of liquid crystallinity at different temperature. • Liquid crystalline pharmaceutical materials often show amorphous behavior along with other characteristics specific to mesomorphous materials. • The thermal and mechanical history of pharmaceutical disordered samples has a significant effect on their phase composition. - Abstract: Characterizing disordered pharmaceutical materials can be challenging, especially materials with partially disordered structures that lose one or two directional order (mesophases) and do not fit the traditional characterization categories of amorphous, crystalline or a combination of the two. Itraconazole, an antifungal agent, was chosen as a model compound that, when quench cooled, exhibits atypical disordered structure. Five different analytical tools were used to map out the molecular structure of this material and how it changes with changing temperature. X-ray diffraction showed some remnant crystallinity while dielectric analysis, dynamic mechanical analysis, DSC and hot stage microscopy gave more detailed molecular structure of the disordered material and explained all temperature related structural changes. The characterization of mesomorphous Itraconazole described here will help characterize a wide range of pharmaceuticals that exhibit thermotropic (temperature induced) mesomorphism at the molecular level.


    Directory of Open Access Journals (Sweden)

    Jiří Pazderka


    Full Text Available There have been many experimental measurements of the waterproofing ability and durability of concrete with a crystalline admixture, but some other important properties have not been reliably tested yet. The results of the tests, carried out by the authors, showed that crystalline admixtures reduce the water vapor permeability of concrete by 16-20 %. The authors also carried out the water pressure test in different time intervals, during the initial phase of cement hydration. The test results have shown that the full waterproofing effect of concrete with a crystalline admixture is available approximately on the 12th day after the concrete creation. The crystalline admixture effect on the compressive strength of concrete was also the subject of the testing. The results have shown that the compressive strength of the concrete with a crystalline admixture (added in an amount of 2 % and the compressive strength of the specimens from concrete without admixture were almost identical after 28 days.

  6. H-Bond stabilized columnar discotic liquid crystals

    NARCIS (Netherlands)

    Paraschiv, I.


    Since 1977, more than 2300 publications on discotic (disk-like) liquid crystalline materials have appeared. Discotic liquid crystals, which usually consist of polyaromatic molecules surrounded by long peripheral alkyl tails, can form liquid crystalline mesophases in a wide temperature range. Within

  7. Terahertz Spectroscopy of Crystalline and Non-Crystalline Solids

    DEFF Research Database (Denmark)

    Parrott, Edward P. J.; Fischer, Bernd M.; Gladden, Lynn F.


    Terahertz spectroscopy of crystalline and non-crystalline solids is probably one of the most active research fields within the terahertz community. Many potential applications, amongst which spectral recognition is probably one of the most prominent, have significantly stimulated the development...

  8. Liquid-solid phase transition of physical hydrogels subject to an externally applied electro-chemo-mechanical coupled field with mobile ionic species. (United States)

    Wu, Tao; Li, Hua


    In this study, a model was multiphysically developed for the simulation of the phase transition of physical hydrogels between liquid solution and solid gel states, subject to an electro-chemo-mechanically coupled field, with the effect of the mobile ionic species in the solution. The present model consists of the governing equations for the equilibrium of forces and the conservation of mass, Maxwell's equations, and an evolution equation for the interface. Based on the second law of thermodynamics, the constitutive equations are formulated from the energy viewpoint, including a novel formulation of free energy with the effect of crosslink density. The present model may be reduced to Suo's non-equilibrium thermodynamic theory if the interface is ignored when only a single phase exists. It may also be reduced to Dolbow's model for gel-gel phase transition when the electric field is ignored. Therefore, the present model becomes more generalized since it is able to represent both the bulk phase and the interface behaviors, and the mechanical field is simultaneously coupled with both the electric and chemical fields. In the first case study, the system at equilibrium state was numerically investigated for analysis of the influences of the electrical and chemical potentials as well as the mechanical pressure externally imposed on the boundary of the system domain. The second case study presents a spherically symmetrical solution-gel phase transition at non-equilibrium states, with the emphasis on the evolution of both the interface and electrochemical potentials.

  9. Bicontinuous liquid crystals

    CERN Document Server

    Lynch, Mathew L


    PrefaceIntroduction AcknowledgmentsBicontinuous Cubic Liquid Crystalline Materials: A Historical Perspective and Modern Assessment; Kr̄e LarssonIntermediate Phases; Michael C. Holmes and Marc S. LeaverCubic Phases and Human Skin: Theory and Practice; Steven Hoath and Lars NorlňThe Relationship between Bicontinuous Inverted Cubic Phases and Membrane Fusion; D.P. SiegelAspects of the Differential Geometry and Topology of Bicontinuous Liquid-Crystalline Phases; Robert W. CorkeryNovel L3 Phases and Their Macroscopic Properties; R. Beck and H. HoffmannBicontinuous Cubic Phases of Lipids with Entra

  10. Crystalline Bioceramic Materials

    Directory of Open Access Journals (Sweden)

    de Aza, P. N.


    Full Text Available A strong interest in the use of ceramics for biomedical engineering applications developed in the late 1960´s. Used initially as alternatives to metallic materials in order to increase the biocompatibility of implants, bioceramics have become a diverse class of biomaterials, presently including three basic types: relatively bioinert ceramics; bioactive or surface reactive bioceramics and bioresorbable ceramics. This review will only refer to bioceramics “sensus stricto”, it is to say, those ceramic materials constituted for nonmetallic inorganic compounds, crystallines and consolidated by thermal treatments of powders to high temperatures. Leaving bioglasses, glass-ceramics and biocements apart, since, although all of them are obtained by thermal treatments to high temperatures, the first are amorphous, the second are obtained by desvitrification of a glass and in them vitreous phase normally prevails on the crystalline phases and the third are consolidated by means of a hydraulic or chemical reaction to room temperature. A review of the composition, physiochemical properties and biological behaviour of the principal types of crystalline bioceramics is given, based on the literature data and on the own experience of the authors.

    A finales de los años sesenta se despertó un gran interés por el uso de los materiales cerámicos para aplicaciones biomédicas. Inicialmente utilizados como una alternativa a los materiales metálicos, con el propósito de incrementar la biocompatibilidad de los implantes, las biocerámicas se han convertido en una clase diversa de biomateriales, incluyendo actualmente tres tipos: cerámicas cuasi inertes; cerámicas bioactivas o reactivas superficialmente y cerámicas reabsorbibles o biodegradables. En la presente revisión se hace referencia a las biocerámicas en sentido estricto, es decir, a aquellos materiales constitutitos por compuestos inorgánicos no metálicos, cristalinos y consolidados

  11. Obesity-Related Metabolomic Analysis of Human Subjects in Black Soybean Peptide Intervention Study by Ultraperformance Liquid Chromatography and Quadrupole-Time-of-Flight Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Min Jung Kim


    Full Text Available The present study aimed to identify key metabolites related to weight reduction in humans by studying the metabolic profiles of sera obtained from 34 participants who underwent dietary intervention with black soybean peptides (BSP for 12 weeks. This research is a sequel to our previous work in which the effects of BSP on BMI and blood composition of lipid were investigated. Sera of the study were subjected to ultra performance liquid chromatography and quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS, and the data were analyzed using partial least-squares discriminate analysis (PLS-DA score plots. Body mass index and percent body fat of the test group were reduced. Levels of betaine, benzoic acid, pyroglutamic acid, pipecolic acid, N-phenylacetamide, uric acid, l-aspartyl-l-phenylalanine, and lysophosphatidyl cholines (lysoPCs (C18:1, C18:2, C20:1, and C20:4 showed significant increases. Levels of l-proline, valine, l-leucine/isoleucine, hypoxanthine, glutamine, l-methionine, phenylpyruvic acid, several carnitine derivatives, and lysoPCs (C14:0, PC16:0, C15:0, C16:0, C17:1, C18:0, and C22:0 were significantly decreased. In particular, lysoPC 16:0 with a VIP value of 12.02 is esteemed to be the most important metabolite for evaluating the differences between the 2 serum samples. Our result confirmed weight-lowering effects of BSP, accompanied by favorable changes in metabolites in the subjects’ blood. Therefore, this research enables us to better understand obesity and increases the predictability of the obesity-related risk by studying metabolites present in the blood.

  12. Crystalline inclusions in granulocytic sarcoma. (United States)

    Strauchen, James A; Gordon, Ronald E


    Two cases of granulocytic sarcoma were found to contain numerous crystalline inclusions identified on hematoxylin-eosin-stained sections as clusters of pointed needlelike crystals present in foci of necrosis or within macrophages. The crystals were negative for chloroacetate esterase and myeloperoxidase. Electron microscopy demonstrated homogeneously dense, bipyramidal structures, indistinguishable from Charcot-Leyden crystals. Granulocytic sarcomas may contain crystalline inclusions similar to Charcot-Leyden crystals; these structures should be distinguished from crystalline immunoglobulin inclusions occurring in cases of plasma cell myeloma and lymphoplasmacytic lymphoma, which may have a similar appearance.

  13. Crystalline silica-induced inflammation



    M. Tech. The persistent presence of neutrophils is associated with a wide range of inflammatory diseases. Resolution of inflammation in these diseases is also associated with the ingestion of apoptotic neutrophils by macrophages. Inflammation and apoptosis of inflammatory cells are common known features observed in the lung following exposure to crystalline silica. What is not known is how well these apoptotic cells are cleared by macrophages in the presence of crystalline silica? To inves...

  14. Phase transitions in liquid crystal 6O. 4 (p-n-hexyloxybenzylidine ...

    Indian Academy of Sciences (India)

    DSC measurements on p--hexyloxybenzylidine-pˊ--butylaniline (6O.4) showed that the crystalline to liquid crystalline (–H) transition at 33.7°C observed in the heating cycle does not revert even when the sample is cooled down to −100°C. Hence it is inferred that a physically stable supercooled liquid crystalline ...

  15. Gamma-irradiation effects to posttranslational modification and chaperon function of bovine {alpha}-crystalline

    Energy Technology Data Exchange (ETDEWEB)

    Hiroki, K; Matsumoto, S.; Awakura, M. [Kyoto Univ., Graduate School of Science, Kyoto (Japan); Fujii, N. [Kyoto Univ., Kumatori, Osaka (Japan). Research Reactor Inst


    The formation of D-asparate (D-Asp) in {alpha}A-crystallin of the aged human eye and the cataract crystalline lens has been reported. Crystalline lens keeps the transparency by forming {alpha}-crystallin which consists of a high order association of {alpha}A-and {alpha}B-crystallin. Bovine {alpha}-crystallin for investigating a chaperone function which protects the crystalline lens from getting to opaque or disordered agglutination with heat or light, is irradiated by gamma-ray (Co-60) at 0, 1, 2, 3, and 4 kGy, respectively. The irradiated bovine {alpha}-crystallin are analyzed with electrophoresis, gel permeation chromatograph, and UV absorption spectrometer for checking on the agglutination and the isomerization of macromolecules. Oxidation of methionine residues (Met-1) and isomerization of asparagine residues (Asp-151) in the {alpha}A-crystallin are ascertained in molecular levels with reversed phase liquid chromatography. The Met-1 oxidation and the Asp-151 isomerization depend on gamma-irradiation doses. It is thought that OH radical and H radical in water generated by the irradiation lead to the oxidation and the isomerization. Stereoinversion in the {alpha}-crystallin following to such a chemical change are considered to lead to the agglutination of polymer and the reduction of chaperon function. (M. Suetake)

  16. Nanoscience with liquid crystals from self-organized nanostructures to applications

    CERN Document Server

    Li, Quan


    This book focuses on the exciting topic of nanoscience with liquid crystals: from self-organized nanostructures to applications. The elegant self-organized liquid crystalline nanostructures, the synergetic characteristics of liquid crystals and nanoparticles, liquid crystalline nanomaterials, synthesis of nanomaterials using liquid crystals as templates, nanoconfinement and nanoparticles of liquid crystals are covered and discussed, and the prospect of fabricating functional materials is highlighted. Contributions, collecting the scattered literature of the field from leading and active player

  17. Design of multi materials combining crystalline and amorphous metallic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Volland, A.; Ragani, J.; Liu, Y.; Gravier, S.; Suery, M. [Grenoble University/CNRS, SIMAP Laboratory, Grenoble INP/UJF, 38402 Saint-Martin d' Heres (France); Blandin, J.J., E-mail: [Grenoble University/CNRS, SIMAP Laboratory, Grenoble INP/UJF, 38402 Saint-Martin d' Heres (France)


    Highlights: Black-Right-Pointing-Pointer Elaboration of multi materials associating metallic glasses and conventional crystalline alloys by co-deformation performed at temperatures close to the glass transition temperature of the metallic glasses. Black-Right-Pointing-Pointer Elaboration of filamentary metal matrix composites with a core in metallic glass by co extrusion. Black-Right-Pointing-Pointer Sandwich structures produced by co-pressing. Black-Right-Pointing-Pointer Detection of atomic diffusion from the glass to the crystalline alloys during the processes. Black-Right-Pointing-Pointer Good interfaces between the metallic glasses and the crystalline alloys, as confirmed by mechanical characterisation. - Abstract: Multi materials, associating zirconium based bulk metallic glasses and crystalline metallic alloys like magnesium alloys or copper are elaborated by co-deformation processing performed in the supercooled liquid regions (SLR) of the bulk metallic glasses. Two processes are investigated: co-extrusion and co-pressing. In the first case, filamentary composites with various designs can be produced whereas in the second case sandwich structures are obtained. The experimental window (temperature, time) in which processing can be carried out is directly related to the crystallisation resistance of the glass which requires getting information about the crystallisation conditions in the selected metallic glasses. Thermoforming windows are identified for the studied BMGs by thermal analysis and compression tests in their SLR. The mechanical properties of the produced multi materials are investigated thanks to specifically developed mechanical devices and the interfaces between the amorphous and the crystalline alloys are characterised.

  18. Preparation of highly (001)-oriented photoactive tungsten diselenide (WSe{sub 2}) films by an amorphous solid-liquid-crystalline solid (aSLcS) rapid-crystallization process

    Energy Technology Data Exchange (ETDEWEB)

    Bozheyev, Farabi; Friedrich, Dennis; Nie, Man; Rengachari, Mythili; Ellmer, Klaus [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Institute for Solar Fuels, Hahn-Meitner-Platz 1, 14109, Berlin (Germany)


    Highly (001)-textured tungsten diselenide WSe{sub 2} thin films have been prepared by a two-step process on quartz glass and TiN metallic back contacts, respectively. At first, X-ray amorphous, selenium-rich WSe{sub 2+x} films were deposited by reactive magnetron sputtering at room temperature onto a thin metal promoter film (Ni or Pd) and afterwards annealed in an H{sub 2}Se/Ar atmosphere. X-ray diffraction and scanning electron microscopy show that highly (001)-oriented WSe{sub 2} films can be grown, which is caused by the formation of liquid promoter-metal selenide droplets which dissolve tungsten or tungsten selenide at temperatures, higher than the eutectic temperature in the promoter metal-selenium system, followed by oversaturation and eventually crystallization of WSe{sub 2} platelets. Time-resolved microwave conductivity measurements show that the films are photoactive. The sum of the carrier mobilities of the best films μ{sub e} + μ{sub h} is in the range of 1-7 cm{sup 2} V{sup -1} s{sup -1}. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Open-cell glass crystalline porous material

    Energy Technology Data Exchange (ETDEWEB)

    Anshits, Alexander G.; Sharonova, Olga M.; Vereshchagina, Tatiana A.; Zykova, Irina D.; Revenko, Yurii A.; Tretyakov, Alexander A.; Aloy, Albert S.; Lubtsev, Rem I.; Knecht, Dieter A.; Tranter, Troy J.; Macheret, Yevgeny


    An open-cell glass crystalline porous material made from hollow microspheres which are cenospheres obtained from fly ash, having an open-cell porosity of up to 90 vol. % is produced. The cenospheres are separated into fractions based on one or more of grain size, density, magnetic or non-magnetic, and perforated or non-perforated. Selected fractions are molded and agglomerated by sintering with a binder at a temperature below the softening temperature, or without a binder at a temperature about, or above, the softening temperature but below the temperature of liquidity. The porous material produced has an apparent density of 0.3-0.6 g/cm.sup.3, a compressive strength in the range of 1.2-3.5 MPa, and two types of openings: through-flow wall pores in the cenospheres of 0.1-30 micrometers, and interglobular voids between the cenospheres of 20-100 micrometers. The porous material of the invention has properties useful as porous matrices for immobilization of liquid radioactive waste, heat-resistant traps and filters, supports for catalysts, adsorbents and ion-exchangers.

  20. Open-cell glass crystalline porous material (United States)

    Anshits, Alexander G.; Sharonova, Olga M.; Vereshchagina, Tatiana A.; Zykova, Irina D.; Revenko, Yurii A.; Tretyakov, Alexander A.; Aloy, Albert S.; Lubtsev, Rem I.; Knecht, Dieter A.; Tranter, Troy J.; Macheret, Yevgeny


    An open-cell glass crystalline porous material made from hollow microspheres which are cenospheres obtained from fly ash, having an open-cell porosity of up to 90 vol. % is produced. The cenospheres are separated into fractions based on one or more of grain size, density, magnetic or non-magnetic, and perforated or non-perforated. Selected fractions are molded and agglomerated by sintering with a binder at a temperature below the softening temperature, or without a binder at a temperature about, or above, the softening temperature but below the temperature of liquidity. The porous material produced has an apparent density of 0.3-0.6 g/cm.sup.3, a compressive strength in the range of 1.2-3.5 MPa, and two types of openings: through-flow wall pores in the cenospheres of 0.1-30 micrometers, and interglobular voids between the cenospheres of 20-100 micrometers. The porous material of the invention has properties useful as porous matrices for immobilization of liquid radioactive waste, heat-resistant traps and filters, supports for catalysts, adsorbents and ion-exchangers.

  1. Crystalline organomercuric acetates via organoboranes

    Energy Technology Data Exchange (ETDEWEB)

    Kunda, S.A.; Varma, R.S.; Kabalka, G.W.


    It is shown that the organomercuric acetates (OMA) can be synthesized rapidly using organomercury derivatives as intermediates. The OMAs can be readily prepared as crystalline solids. The reactions proceed with sufficient rapidity to make the synthesis useful for isotopic labelling of physiologically active compounds.

  2. On doubly stratified chemically reactive flow of Powell–Eyring liquid subject to non-Fourier heat flux theory

    Directory of Open Access Journals (Sweden)

    T. Hayat

    Full Text Available This investigation addresses the chemical reaction and double stratification effects in the flow induced by a nonlinear stretching surface with variable thickness. Flow formulation is developed using rheological expressions of Eyring–Powell liquid. Salient features of heat transfer are examined by considering non-Fourier heat flux model. Formulation is arranged for variable thermal conductivity. Flux model under consideration is the generalized form of Fourier’s classical expression with thermal relaxation time. Ordinary differential systems are obtained through implementation of appropriate transformations. Convergent series solutions are constructed. Non-dimensional velocity, temperature, concentration, skin friction and Sherwood number are displayed and discussed. It is anticipated that thermal and concentration stratified parameters decay the temperature and concentration respectively. Keywords: Double stratification, Chemical reaction, Eyring–Powell liquid, Non-Fourier heat flux model, Variable thermal conductivity

  3. Generic Crystalline Disposal Reference Case

    Energy Technology Data Exchange (ETDEWEB)

    Painter, Scott Leroy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chu, Shaoping [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Harp, Dylan Robert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Perry, Frank Vinton [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wang, Yifeng [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)


    A generic reference case for disposal of spent nuclear fuel and high-level radioactive waste in crystalline rock is outlined. The generic cases are intended to support development of disposal system modeling capability by establishing relevant baseline conditions and parameters. Establishment of a generic reference case requires that the emplacement concept, waste inventory, waste form, waste package, backfill/buffer properties, EBS failure scenarios, host rock properties, and biosphere be specified. The focus in this report is on those elements that are unique to crystalline disposal, especially the geosphere representation. Three emplacement concepts are suggested for further analyses: a waste packages containing 4 PWR assemblies emplaced in boreholes in the floors of tunnels (KBS-3 concept), a 12-assembly waste package emplaced in tunnels, and a 32-assembly dual purpose canister emplaced in tunnels. In addition, three failure scenarios were suggested for future use: a nominal scenario involving corrosion of the waste package in the tunnel emplacement concepts, a manufacturing defect scenario applicable to the KBS-3 concept, and a disruptive glaciation scenario applicable to both emplacement concepts. The computational approaches required to analyze EBS failure and transport processes in a crystalline rock repository are similar to those of argillite/shale, with the most significant difference being that the EBS in a crystalline rock repository will likely experience highly heterogeneous flow rates, which should be represented in the model. The computational approaches required to analyze radionuclide transport in the natural system are very different because of the highly channelized nature of fracture flow. Computational workflows tailored to crystalline rock based on discrete transport pathways extracted from discrete fracture network models are recommended.

  4. Liquid crystals in biotribology synovial joint treatment

    CERN Document Server

    Ermakov, Sergey; Eismont, Oleg; Nikolaev, Vladimir


    This book summarizes the theoretical and experimental studies confirming the concept of the liquid-crystalline nature of boundary lubrication in synovial joints. It is shown that cholesteric liquid crystals in the synovial liquid play a significant role in the mechanism of intra-articular friction reduction. The results of structural, rheological and tribological research of the creation of artificial synovial liquids - containing cholesteric liquid crystals in natural synovial liquids - are described. These liquid crystals reproduce the lubrication properties of natural synovia and provide a high chondroprotective efficiency. They were tested in osteoarthritis models and in clinical practice.

  5. The physics of large deformation of crystalline solids

    CERN Document Server

    Bell, James F


    Historically, a major problem for the study of the large deformation of crystalline solids has been the apparent lack of unity in experimentally determined stress-strain functions. The writer's discovery in 1949 of the unexpectedly high velocity of incremental loading waves in pre-stressed large deformation fields emphasized to him the pressing need for the independent, systematic experimental study of the subject, to provide a firm foundation upon which physically plausible theories for the finite deformation of crystalline solids could be constructed. Such a study undertaken by the writer at that time and continued uninterruptedly to the present, led in 1956 to the development of the diffraction grating experiment which permitted, for the first time, the optically accurate determination of the strain-time detail of non-linear finite amplitude wave fronts propagating into crystalline solids whose prior history was precisely known. These experimental diffraction grating studies during the past decade have led...

  6. Liquids and liquid mixtures

    CERN Document Server

    Rowlinson, J S; Baldwin, J E; Buckingham, A D; Danishefsky, S


    Liquids and Liquid Mixtures, Third Edition explores the equilibrium properties of liquids and liquid mixtures and relates them to the properties of the constituent molecules using the methods of statistical thermodynamics. Topics covered include the critical state, fluid mixtures at high pressures, and the statistical thermodynamics of fluids and mixtures. This book consists of eight chapters and begins with an overview of the liquid state and the thermodynamic properties of liquids and liquid mixtures, including vapor pressure and heat capacities. The discussion then turns to the thermodynami

  7. Morphology and crystallinity of sisal nanocellulose after sonication (United States)

    Sosiati, H.; Wijayanti, D. A.; Triyana, K.; Kamiel, B.


    Different preparation methods on the natural fibers resulted in different morphology. However, the relationships between type of natural fibers, preparation methods and the morphology of produced nanocellulose could not be exactly defined. The sisal nanocellulose was presently prepared by alkalization and bleaching followed by sonication to verify changes in the morphology and crystallinity of nanocellulose related to the formation mechanism. The extracted microcellulose was subjected to scanning electron microscopy (SEM) and x-ray diffraction (XRD) analysis. The isolated cellulose nanospheres were examined with respect to morphology by SEM and transmission electron microscopy (TEM) and, to crystallinity by electron diffraction analysis. Bleaching after alkalization made the microfibrils clearly separated from each other to the individual fiber whose width of the single fiber was ranging from 6 to 13 µm. The XRD crystallinity index (CI) of microcellulose gradually increased after the chemical treatments; 83.12% for raw sisal fiber, 88.57% for alkali treated fiber and 94.03% for bleached fibers. The ultrasonic agitation after bleaching that was carried out at 750 Watt, 20 kHz and amplitude of 39% for 2 h produces homogeneous cellulose nanospheres less than 50 nm in diameter with relatively low crystallinity. The electron diffraction analysis confirmed that the low crystallinity of produced nnocellulose is related to the effect of chemical treatment done before sonication.

  8. Programmable high crystallinity carbon patterns (United States)

    Wang, Xuewen; Wang, Hong; Gu, Yang; Fu, Wei; Zheng, Lu; Liu, Guowei; He, Yongmin; Long, Yi; Zhao, Wu; Zhang, Jie; Zhang, Ting; Liu, Zheng


    Carbon nanomaterials such as carbon nanotube and graphene are promising candidates for next-generation flexible electronics. However, the practical application of carbon electronics requires controlled fabrication of those materials with micro-patterned structures on flexible substrate at wafer-scale and low cost. Inspiring from the conventional photolithography process and pyrolysis of photoresist, herein, we demonstrate the synthesis of high-quality micro-patterned high crystallinity carbon. The method employed pre-patterned pyrolyzed photoresist as carbon precursors, in order to minimize the mobility of carbon during the high temperature growth, which results into high quality carbon patterns with a lateral resolution up to ~2 µm. The flexible carbon electronics are demonstrated by transferring the as-patterned high crystallinity carbon patterns to the flexible substrate, and showing asymmetric tensile-compressive response with high output resolution. These results will pave the way to the next-generation carbon-based flexible electronics and mechanical sensors.

  9. Amorphous silicon crystalline silicon heterojunction solar cells

    CERN Document Server

    Fahrner, Wolfgang Rainer


    Amorphous Silicon/Crystalline Silicon Solar Cells deals with some typical properties of heterojunction solar cells, such as their history, the properties and the challenges of the cells, some important measurement tools, some simulation programs and a brief survey of the state of the art, aiming to provide an initial framework in this field and serve as a ready reference for all those interested in the subject. This book helps to "fill in the blanks" on heterojunction solar cells. Readers will receive a comprehensive overview of the principles, structures, processing techniques and the current developmental states of the devices. Prof. Dr. Wolfgang R. Fahrner is a professor at the University of Hagen, Germany and Nanchang University, China.

  10. Biocompatibility of crystalline opal nanoparticles

    Directory of Open Access Journals (Sweden)

    Hernández-Ortiz Marlen


    Full Text Available Abstract Background Silica nanoparticles are being developed as a host of biomedical and biotechnological applications. For this reason, there are more studies about biocompatibility of silica with amorphous and crystalline structure. Except hydrated silica (opal, despite is presents directly and indirectly in humans. Two sizes of crystalline opal nanoparticles were investigated in this work under criteria of toxicology. Methods In particular, cytotoxic and genotoxic effects caused by opal nanoparticles (80 and 120 nm were evaluated in cultured mouse cells via a set of bioassays, methylthiazolyldiphenyl-tetrazolium-bromide (MTT and 5-bromo-2′-deoxyuridine (BrdU. Results 3T3-NIH cells were incubated for 24 and 72 h in contact with nanocrystalline opal particles, not presented significant statistically difference in the results of cytotoxicity. Genotoxicity tests of crystalline opal nanoparticles were performed by the BrdU assay on the same cultured cells for 24 h incubation. The reduction of BrdU-incorporated cells indicates that nanocrystalline opal exposure did not caused unrepairable damage DNA. Conclusions There is no relationship between that particles size and MTT reduction, as well as BrdU incorporation, such that the opal particles did not induce cytotoxic effect and genotoxicity in cultured mouse cells.

  11. Inactivation of Escherichia coli O157:H7 and Salmonella deposited on gloves in a liquid state and subjected to drying conditions. (United States)

    Erickson, Marilyn C; Liao, Jye-Yin; Webb, Cathy C; Habteselassie, Mussie Y; Cannon, Jennifer L


    Gloves are worn by workers harvesting ready-to-eat produce as a deterrent for contaminating the produce with enteric pathogens that may reside on their hands. As fields are not sterile environments, the probability for gloves to become contaminated still exists and therefore it is critical to understand the conditions that affect the survival of pathogens on gloves. Both Escherichia coli O157:H7 and Salmonella deposited on glove surfaces in a liquid state survived longer when the pathogen had been suspended in lettuce sap than when suspended in water. Despite this protection, pathogens deposited on clean single-use gloves were more likely to survive during drying than pathogens deposited on dirty gloves (a film of lettuce sap had been applied to the surface prior to pathogen application and soil had been ground into the gloves). Survival of both E. coli O157:H7 and Salmonella was biphasic with the greatest losses occurring during the first hour of drying followed by much slower losses in the ensuing hours. Pathogens grown in rich media (tryptic soy broth) versus minimal media (M9) as well as those cultured on solid agar versus liquid broth were also more likely to be resistant to desiccation when deposited onto gloves. Although survival of E. coli O157:H7 on nitrile gloves was in general greater than it was on latex gloves, the relative survival of Salmonella on the two glove types was inconsistent. Due to these inconsistencies, no one glove type is considered better than another in reducing the risk for contamination with enteric pathogens. In addition, the extended survival of what are generally referred to as stress-resistant pathogens suggests that gloves either be changed frequently during the day or washed in a disinfectant to reduce the risk of glove contamination that could otherwise contaminate product handled with the contaminated gloves. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. The Effect of Diluted Penetration Enhancer in Nebulized Mist versus Liquid Drop Preparation Forms on Retrobulbar Blood Flow in Healthy Human Subjects

    Directory of Open Access Journals (Sweden)

    Ruta Barsauskaite


    Full Text Available The aim of this study was to compare the effects of nebulized mist and liquid drop applications on retrobulbar blood flow. A prospective, non-randomized clinical trial was used to collect data from 40 healthy human eyes. Color Doppler Imaging determined peak systolic (PSV and end diastolic (EDV blood flow velocities and resistance index (RI in the ophthalmic artery after both applications. Measurements were taken at baseline and at 1 min post-treatment in both eyes with 5 min measurements in the treatment eye only. p values ≤ 0.05 were considered statistically significant. Mist application to treatment eye produced an increase in 1 min and 5 min PSV and EDV (0.001 < p < 0.03 and a decrease in 5 min RI (p = 0.01, with no significant changes in PSV, EDV or RI of control eye or in treatment eye 1 min RI (p > 0.05. Drop application to treatment eye produced an increase in PSV (p < 0.001 and EDV (p = 0.01 at 1 min, with an increase in control eye 1 min PSV and EDV (p = 0.03. There were no statistically significant changes in treatment eye PSV, EDV and RI after 5 min (p > 0.05. The use of nebulized mist may provide an effective alternative to liquid drop medication application.

  13. Solid-state vitrification of crystalline griseofulvin by mechanical milling. (United States)

    Willart, Jean-François; Carpentier, Laurent; Danède, Florence; Descamps, Marc


    The thermodynamic, dynamic, and structural changes of crystalline griseofulvin upon high-energy ball milling at room temperature have been studied. The investigations have been performed by differential scanning calorimetry (DSC), dielectric relaxation spectroscopy, and powder X-ray diffraction. The results indicate that this compound undergoes a direct crystal-to-glass transformation upon milling, whereas no glass transition can be clearly detected upon heating because of the exceptional sub-glass transition temperature (T(g) ) recrystallization of the milled sample. This intrinsic difficulty for characterizing the glassy state has been overcome using three independent strategies: (i) comparison of the evolutions upon milling of both the crystalline powder and the quenched liquid, (ii) use of fast DSC to delay the recrystallization event, and (iii) search for dielectric β relaxations typical of glasses in the milled compound. Copyright © 2012 Wiley Periodicals, Inc.

  14. Investigations on the liquid crystalline phases of cation-induced ...

    Indian Academy of Sciences (India)

    Regional Research Laboratory, Thiruvananthapuram 695 019, India; Rajeev Gandhi Centre for Biotechnology, Thiruvananthapuram 695 014, India; Departments of Medicine and Environmental and Community Medicine, University of Medicine and Dentistry, Robert Wood Johnson Medical School, NJ 08903, USA ...

  15. Thermotropic liquid crystalline polyesters derived from 2-chloro ...

    Indian Academy of Sciences (India)



    -hydroxy benzoyloxy]-. 2-chloro-1,4-benzene (BHBOCB) and aliphatic dicarboxylic acid chlorides by interfacial polycondensation methodology is presented. Synthesised polyesters consist of bis[4-hydroxy ...

  16. Liquid crystalline behaviour of mixtures of structurally dissimilar ...

    Indian Academy of Sciences (India)


    components, viz. 4-nitrophenyl-4′-n-alkoxybenzoates (where n-alkoxy is n- butoxy, C4, n-hexyloxy, C6, n-octyloxy, C8 and n-decyloxy, C10) and one azo component, 4-n-decyloxy phenylazo-4′-isoamyloxy benzene. A variety of mesomorphic properties are observed in these mixtures. The properties of these systems are ...

  17. Investigations on the liquid crystalline phases of cation-induced ...

    Indian Academy of Sciences (India)

    3Departments of Medicine and Environmental and Community Medicine, University of Medicine and Dentistry, Robert Wood Johnson Medical School, NJ 08903, USA. E-mail: Abstract. ..... Thanks are due to DST, New Delhi for providing funds under the new nanotech- nology initiative. References.


    NARCIS (Netherlands)

    Wilsens, Karel


    Thermotropic polyesters are an important class of materials for high erformance applications. Their low melt viscosities, low thermal expansion coefficients, high use temperatures, and ease in processing allow for the production of high strength and high modulus fibers, films, or compression-molded

  19. Preparation and pharmacokinetic study of fenofibrate cubic liquid crystalline

    Directory of Open Access Journals (Sweden)

    Shijie Wei


    Full Text Available An LCC delivery system for Fenofibrate (Fen was developed to improve its poorly oral bioavailability. Fen-LCC preparation methods were screened, and the prepared Fen-LCC was then characterized by a polarizing microscope and transmission electron microscopy (TEM. The spray drying technique was selected to dry and solidify particles into powder. The in vitro release of Fen-LCC was measured and in vivo pharmacokinetic experiments were carried out on rats after oral administration. Particles prepared through the high-temperature input method exhibited structural characteristics of LCC, and re-dissolved particles maintained the same features. The LCC delivery system can significantly improve in vitro release outcomes. After oral administration, AUCs of the suspension and LCC systems were measured at 131.6853 µg⋅h/ml and 1435.72893 µg⋅h/ml, respectively. The spray drying process presented here better maintains cubic structures, and the LCC system significantly improves bioavailability levels.

  20. Protective Effects of Acetylation on the Pathological Reactions of the Lens Crystallins with Homocysteine Thiolactone.

    Directory of Open Access Journals (Sweden)

    Zeinab Moafian

    Full Text Available Various post-translational lens crystallins modifications result in structural and functional insults, contributing to the development of lens opacity and cataract disorders. Lens crystallins are potential targets of homocysteinylation, particularly under hyperhomocysteinemia which has been indicated in various eye diseases. Since both homocysteinylation and acetylation primarily occur on protein free amino groups, we applied different spectroscopic methods and gel mobility shift analysis to examine the possible preventive role of acetylation against homocysteinylation. Lens crystallins were extensively acetylated in the presence of acetic anhydride and then subjected to homocysteinylation in the presence of homocysteine thiolactone (HCTL. Extensive acetylation of the lens crystallins results in partial structural alteration and enhancement of their stability, as well as improvement of α-crystallin chaperone-like activity. In addition, acetylation partially prevents HCTL-induced structural alteration and aggregation of lens crystallins. Also, acetylation protects against HCTL-induced loss of α-crystallin chaperone activity. Additionally, subsequent acetylation and homocysteinylation cause significant proteolytic degradation of crystallins. Therefore, further experimentation is required in order to judge effectively the preventative role of acetylation on the structural and functional insults induced by homocysteinylation of lens crystallins.

  1. Examination of the anisotropy of the wetting behaviour of liquid Al-Cu alloys on single crystalline oriented Al{sub 2}O{sub 3}-substrates; Untersuchung der Anisotropie im Benetzungsverhalten fluessiger Al-Cu Legierungen auf einkristallinen orientierten Al{sub 2}O{sub 3}-Substraten

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, Julianna


    The wetting behaviour of liquid Al-Cu alloys and pure metals on oriented single crystalline Al{sub 2}O{sub 3}-substrates was examined, utilising the sessile drop technique. Measurements were performed at moderate temperatures of 1100 C, where the alloys are liquid. Different Al{sub 2}O{sub 3}-surfaces were studied, which are terminated by the crystallographic planes (0001), (11 anti 20), and (1 anti 102), also called C-, A-, and R-surfaces. After deposition, pure Cu-droplets show an exponential increase of the wetting angle to a value of about 115 for all investigated Al{sub 2}O{sub 3}-surfaces. The timescale of this increase is of the order of 100 s. The effect of surface- and interfacial energies on the wetting angle is discussed considering Young's equation. The most probable reason for its time-dependence seems to be an increase of the interfacial energy due to deoxidation of the droplet. Therefore it is reasonable to regard the isotropic contact angle value as the intrinsic one of the Cu/Al{sub 2}O{sub 3} system. In contrast, the wetting angle of pure Al metal with the different Al{sub 2}O{sub 3}-substrates shows a qualitatively different behaviour. In this system, it rises from about 90 to 115 roughly for C-substrates, twice as fast as in the Cu case but to a comparable value. On the other substrates a wetting angle of about 90 establishes immediately, and no pronounced time dependence is obvious. In order to study changes in the wetting behaviour of Al-Cu-alloys, which is isotropic for Cu and anisotropic for Al-rich alloys, contact angles of Al{sub 50}Cu{sub 50}, Al{sub 30}Cu{sub 70} und Al{sub 17}Cu{sub 83} on Al{sub 2}O{sub 3} were determined. For each alloy composition the wetting angle is about 120 after 300 s. The initial values on distinct surfaces hardly differ and become non-wetting with increasing Cu-content. Hence, anisotropy decreases. To determine the work of adhesion of the solid-liquid interface, the temperature- and composition

  2. Alignment technology and applications of liquid crystal devices

    CERN Document Server

    Takatoh, Kohki; Hasegawa, Ray; Koden, Mitsushiro; Itoh, Nobuyuki; Hasegawa, Masaki


    Alignment phenomena are characteristic of liquid crystalline materials, and understanding them is critically important in understanding the essential features and behavior of liquid crystals and the performance of Liquid Crystal Devices (LCDs). Furthermore, in LCD production lines, the alignment process is of practical importance. Alignment Technologies and Applications of Liquid Crystal Devices demonstrates both the fundamental and practical aspects of alignment phenomena in liquid crystals. The physical basis of alignment phenomena is first introduced in order to aid the understanding of the various physical phenomena observed in the interface between liquid crystalline materials and alignment layer surfaces. Methods for the characterization of surfaces, which induce the alignment phenomena, and of the alignment layer itself are introduced. These methods are useful for the research of liquid crystalline materials and devices in academic research as well as in industry. In the practical sections, the alignme...

  3. Passive Sensor Materials Based on Liquid Crystals (United States)


    Seminar, Chemical Engineering,,Virginia Tech, October, 2008. Abbott, N.L. “Biomolecular Analysis based on Liquid Crystals”, Innovative Molecular Analysis ...of Liquid Crystals" Columbia University, February, 2010, "Novel Colloidal and Interfacial Phenomena in Liquid Crystalline Systems" CBD Conference...extended to other oils (silicone oil and paraffin oil droplets) and the size of capsule templates was also varied (0.7 to 10 μm, Figure 15) to

  4. Liquid metal-organic frameworks (United States)

    Gaillac, Romain; Pullumbi, Pluton; Beyer, Kevin A.; Chapman, Karena W.; Keen, David A.; Bennett, Thomas D.; Coudert, François-Xavier


    Metal-organic frameworks (MOFs) are a family of chemically diverse materials, with applications in a wide range of fields, covering engineering, physics, chemistry, biology and medicine. Until recently, research has focused almost entirely on crystalline structures, yet now a clear trend is emerging, shifting the emphasis onto disordered states, including `defective by design’ crystals, as well as amorphous phases such as glasses and gels. Here we introduce a strongly associated MOF liquid, obtained by melting a zeolitic imidazolate framework. We combine in situ variable temperature X-ray, ex situ neutron pair distribution function experiments, and first-principles molecular dynamics simulations to study the melting phenomenon and the nature of the liquid obtained. We demonstrate from structural, dynamical, and thermodynamical information that the chemical configuration, coordinative bonding, and porosity of the parent crystalline framework survive upon formation of the MOF liquid.

  5. Liquid metal–organic frameworks

    Energy Technology Data Exchange (ETDEWEB)

    Gaillac, Romain; Pullumbi, Pluton; Beyer, Kevin A.; Chapman, Karena W.; Keen, David A.; Bennett, Thomas D.; Coudert, François-Xavier


    Metal–organic frameworks (MOFs) are a family of chemically diverse materials, with applications in a wide range of fields, covering engineering, physics, chemistry, biology and medicine. Until recently, research has focused almost entirely on crystalline structures, yet now a clear trend is emerging, shifting the emphasis onto disordered states, including ‘defective by design’ crystals, as well as amorphous phases such as glasses and gels. Here we introduce a strongly associated MOF liquid, obtained by melting a zeolitic imidazolate framework. We combine in situ variable temperature X-ray, ex situ neutron pair distribution function experiments, and first-principles molecular dynamics simulations to study the melting phenomenon and the nature of the liquid obtained. We demonstrate from structural, dynamical, and thermodynamical information that the chemical configuration, coordinative bonding, and porosity of the parent crystalline framework survive upon formation of the MOF liquid.

  6. A silent mutation in human alpha-A crystallin gene in patients with age-related nuclear or cortical cataract

    Directory of Open Access Journals (Sweden)

    Bharani K Mynampati


    Full Text Available A cataract is a complex multifactorial disease that results from alterations in the cellular architecture, i.e. lens proteins. Genes associated with the development of lens include crystallin genes. Although crystallins are highly conserved proteins among vertebrates, a significant number of polymorphisms exist in human population. In this study, we screened for polymorphisms in crystallin alpha A (CRYAA and alpha B (CRYAB genes in 200 patients over 40 years of age, diagnosed with age-related cataract (ARC; nuclear and cortical cataracts. Genomic DNA was extracted from the peripheral blood. The coding regions of the CRYAA and CRYAB gene were amplified using polymerase chain reaction and subjected to restriction digestion. Restriction fragment length polymorphism (RFLP was performed using known restriction enzymes for CRYAA and CRYAB genes. Denaturing high performance liquid chromatography and direct sequencing were performed to detect sequence variation in CRYAA gene. In silico analysis of secondary CRYAA mRNA structure was performed using CLC RNA Workbench. RFLP analysis did not show any changes in the restriction sites of CRYAA and CRYAB genes. In 6 patients (4 patients with nuclear cataract and 2 with cortical cataract, sequence analysis of the exon 1 in the CRYAA gene showed a silent single nucleotide polymorphism [D2D] (CRYAA: C to T transition. One of the patients with nuclear cataract was homozygous for this allele. The in silico analysis revealed that D2D mutation results in a compact CRYAA mRNA secondary structure, while the wild type CRYAA mRNA has a weak or loose secondary structure. D2D mutation in the CRYAA gene may be an additional risk factor for progression of ARC.

  7. Phase transitions in liquid crystal 6O.4 (pn-hexyloxybenzylidine-p -n ...

    Indian Academy of Sciences (India)

    ) showed that the crystalline to liquid crystalline (K–SH) transition at 33.7◦C observed in the heating cycle does not revert even when the sample is cooled down to −100◦C. Hence it is inferred that a physically stable supercooled liquid ...

  8. [Crystalline lens photodisruption using femtosecond laser: experimental study]. (United States)

    Chatoux, O; Touboul, D; Buestel, C; Balcou, P; Colin, J


    The aim of this study was to analyze the interactions during femtosecond (fs) laser photodisruption in ex vivo porcine crystalline lenses and to study the parameters for laser interaction optimization. An experimental femtosecond laser was used. The laser characteristics were: 1030 nm wavelength; pulse duration, 400 fs; and numerical aperture, 0.13. Specific software was created to custom and monitor any type of photoablation pattern for treatment purposes. Porcine crystalline lenses were placed in an open sky holder filled with physiological liquid (BSS) covered by a glass plate. A numerical camera was associated with metrological software in order to magnify and quantify the results. Transmission electron microscopy (TEM) was performed on some samples to identify the microscopic plasma interactions with the lens. The optimization of parameters was investigated in terms of the optical breakdown threshold, the sizing of interactions, and the best pattern for alignments. More than 150 crystalline lenses of freshly enucleated pigs were treated. The optical breakdown threshold (OBT) was defined as the minimal energy level per pulse necessary to observe a physical interaction. In our study, the OBT varied according to the following parameters: the crystalline lens itself, varying from 4.2 to 7.6 μJ (mean, 5.1 μJ), and the depth of laser focus, varying up to 1 μJ, increasing in the depth of the tissue. Analyzing the distance between impacts, we observed that the closer the impacts were the less power was needed to create a clear well-drawn defect pattern (lines), i.e., with a 4-μJ optimized OBT, when the impacts were placed every 2 μm for the x,y directions and 60 μm for the z direction. Coalescent bubbles created by plasma formation always disappeared in less than 24h. The nonthermal effect of plasma and the innocuousness on surrounding tissues were proven by the TEM results. The crystalline lens photodisruption by the femtosecond laser seems an innovative

  9. First Fullerene[60]-Containing Thermotropic Liquid Crystal. Preliminary Communication


    Chuard, Thierry; Deschenaux, Robert


    The synthesis and liquid-crystalline and thermal properties of a fullerene[60] functionalized by a framework containing two cholesterol derivatives through a methanofullerene structure are reported. The targeted fullerene derivative showed high thermal stability.

  10. Pendant triazole ring assisted mesogen containing side chain liquid ...

    Indian Academy of Sciences (India)

    yl containing side- chain liquid-crystalline polymethacrylates were synthesized by free radical polymerization technique. Mesogen was linked to backbone through various spacer units. Monomers and polymers were characterized by FT-IR, 1H ...

  11. Macroscopic diffusion models for precipitation in crystalline gallium arsenide

    Energy Technology Data Exchange (ETDEWEB)

    Kimmerle, Sven-Joachim Wolfgang


    Based on a thermodynamically consistent model for precipitation in gallium arsenide crystals including surface tension and bulk stresses by Dreyer and Duderstadt, we propose two different mathematical models to describe the size evolution of liquid droplets in a crystalline solid. The first model treats the diffusion-controlled regime of interface motion, while the second model is concerned with the interface-controlled regime of interface motion. Our models take care of conservation of mass and substance. These models generalise the well-known Mullins- Sekerka model for Ostwald ripening. We concentrate on arsenic-rich liquid spherical droplets in a gallium arsenide crystal. Droplets can shrink or grow with time but the centres of droplets remain fixed. The liquid is assumed to be homogeneous in space. Due to different scales for typical distances between droplets and typical radii of liquid droplets we can derive formally so-called mean field models. For a model in the diffusion-controlled regime we prove this limit by homogenisation techniques under plausible assumptions. These mean field models generalise the Lifshitz-Slyozov-Wagner model, which can be derived from the Mullins-Sekerka model rigorously, and is well understood. Mean field models capture the main properties of our system and are well adapted for numerics and further analysis. We determine possible equilibria and discuss their stability. Numerical evidence suggests in which case which one of the two regimes might be appropriate to the experimental situation. (orig.)

  12. Photoresponsive Liquid Crystals Based on Dihydroazulene

    DEFF Research Database (Denmark)

    Petersen, Anne Ugleholdt

    The main focus of this thesis was a study upon photoresponsive liquid crystalline materials,with a starting point on the photoactive compound dihydroazulene (DHA). It has been shown thatsome DHAs with liquid crystalline properties can be synthesized, having an aliphatic substituent atthe 2-position....... Irradiation of such a DHA in the nematic phase gave partial conversion to avinylheptafulvene (VHF), not showing any changes in the mesophase, though a higher alignmentwas obtained when this sample was irradiated in its liquid crystalline state.Photomicrographs of the DHA under crossed polarizers before...... irradiation, after irradiation and when allowed toclose back to the DHAFor a disubstituted DHAs, with substituents in both the 2- and 7-positions, it was shown thatthese materials were unstable when heated above 100 °C, leading to side reactions, whichcomplicated analysis of the system. When doped...

  13. Liquid Marbles

    KAUST Repository

    Khalil, Kareem


    Granulation, the process of formation of granules from a combination of base powders and binder liquids, has been a subject of research for almost 50 years, studied extensively for its vast applications, primarily to the pharmaceutical industry sector. The principal aim of granulation is to form granules comprised of the active pharmaceutical ingredients (API’s), which have more desirable handling and flowability properties than raw powders. It is also essential to ensure an even distribution of active ingredients within a tablet with the goal of achieving time‐controlled release of drugs. Due to the product‐specific nature of the industry, however, data is largely empirical [1]. For example, the raw powders used can vary in size by two orders of magnitude with narrow or broad size distributions. The physical properties of the binder liquids can also vary significantly depending on the powder properties and required granule size. Some significant progress has been made to better our understanding of the overall granulation process [1] and it is widely accepted that the initial nucleation / wetting stage, when the binder liquid first wets the powders, is key to the whole process. As such, many experimental studies have been conducted in attempt to elucidate the physics of this first stage [1], with two main mechanisms being observed – classified by Ivenson [1] as the “Traditional description” and the “Modern Approach”. See Figure 1 for a graphical definition of these two mechanisms. Recent studies have focused on the latter approach [1] and a new, exciting development in this field is the Liquid Marble. This interesting formation occurs when a liquid droplet interacts with a hydrophobic (or superhydrophobic) powder. The droplet can become encased in the powder, which essentially provides a protective “shell” or “jacket” for the liquid inside [2]. The liquid inside is then isolated from contact with other solids or liquids and has some

  14. Influence of string-like cooperative atomic motion on surface diffusion in the (110) interfacial region of crystalline Ni (United States)

    Zhang, Hao; Yang, Ying; Douglas, Jack F.


    Although we often think about crystalline materials in terms of highly organized arrays of atoms, molecules, or even colloidal particles, many of the important properties of this diverse class of materials relating to their catalytic behavior, thermodynamic stability, and mechanical properties derive from the dynamics and thermodynamics of their interfacial regions, which we find they have a dynamics more like glass-forming (GF) liquids than crystals at elevated temperatures. This is a general problem arising in any attempt to model the properties of naturally occurring crystalline materials since many aspects of the dynamics of glass-forming liquids remain mysterious. We examine the nature of this phenomenon in the "simple" case of the (110) interface of crystalline Ni, based on a standard embedded-atom model potential, and we then quantify the collective dynamics in this interfacial region using newly developed methods for characterizing the cooperative dynamics of glass-forming liquids. As in our former studies of the interfacial dynamics of grain-boundaries and the interfacial dynamics of crystalline Ni nanoparticles (NPs), we find that the interface of bulk crystalline Ni exhibits all the characteristics of glass-forming materials, even at temperatures well below the equilibrium crystal melting temperature, Tm. This perspective offers a new approach to modeling and engineering the properties of crystalline materials.

  15. Towards understanding the local structure of liquids (United States)

    Patashinski, Alexander Z.; Mitus, Antoni C.; Ratner, Mark A.


    In this article we discuss the problem of well-defined crystalline patterns of local atomic arrangements in equilibrium liquids, and their statistical mechanics modelling. We present arguments in favor of the existence of local crystalline structures in liquids (local crystal order hypothesis) and discuss a generalized energy landscape picture in the theory of the liquid state. This picture allows a quantification of the hypothesis of local order and offers basic concepts for the statistical mechanics modelling of the melting phase transition. We review recent results of probabilistic-based searches for local structures in various two- and three-dimensional computer-simulated liquids. Next, some statistical-mechanics models of melting and amorphization in terms of structural states of small clusters are proposed. The models, which have only two characteristic energies, that of the orientationally disordered locally crystalline state, and that of completely amorphous state, are studied in a mean-probability approximation. If the amorphization energy is high, the material retains local crystallinity even in the melt; at higher temperatures a crossover to the locally amorphous state occurs. A material that has a low energy non-crystalline local packing exhibits an amorphization melting; the phase transition is from orientationally ordered crystal state to a locally amorphous melt.

  16. Molecular Dynamics Study on Lubrication Mechanism in Crystalline Structure between Copper and Sulfur

    Directory of Open Access Journals (Sweden)

    Ken-ichi Saitoh


    Full Text Available To clarify the nanosized mechanism of good lubrication in copper disulfide (Cu2S crystal which is used as a sliding material, atomistic modeling of Cu2S is conducted and molecular dynamics (MD simulations are performed in this paper. The interatomic interaction between atoms and crystalline structure in the phase of hexagonal crystal of Cu2S are carefully estimated by first-principle calculations. Then, approximating these interactions, we originally construct a conventional interatomic potential function of Cu2S crystal in its hexagonal phase. By using this potential function, we perform MD simulation of Cu2S crystal which is subjected to shear loading parallel to the basal plane. We compare results obtained by different conditions of sliding directions. Unlike ordinary hexagonal metallic crystals, it is found that the easy-glide direction does not always show small shear stress for Cu2S crystal. Besides, it is found that shearing velocity affects largely the magnitude of averaged shear stress. Generally speaking, higher velocity results in higher resistance against shear deformation. As a result, it is understood that Cu2S crystal exhibits somewhat liquid-like (amorphous behavior in sliding condition and shear resistance increases with increase of sliding speed.

  17. Thermal and Optical Characterization of Polymer-Dispersed Liquid Crystals


    Shanks, Robert A.; Daniel Staszczyk


    Liquid crystals are compounds that display order in the liquid state above the melting temperature and below the mesogenic isotropic temperature. Polymer-dispersed liquid crystals (PDLCs) are composite materials in which liquid crystalline material is dispersed within a polymer matrix to form micron-sized droplets. The aim was to prepare several cholesteryl esters or alkoxybenzoic acid PDLCs and characterise thermal and optical properties. Differential scanning calorimetry and polarized optic...

  18. Syntheses, molecular and crystalline architectures, and ...

    Indian Academy of Sciences (India)

    Syntheses, molecular and crystalline architectures, and luminescence behaviour of terephthalate bridged heptacoordinated dinuclear lead(II) complexes containing a pentadentate N-donor Schiff base. SUBHASIS ROYa, SOMNATH CHOUBEYa, SUMITAVA KHANa, KISHALAY BHARa,. PARTHA MITRAb and BARINDRA ...

  19. Optical waveguides in hard crystalline materials

    NARCIS (Netherlands)

    Pollnau, Markus


    The recent results of our research group and collaborators in the field of fabrication, characterization, and applications of optical waveguides in hard crystalline materials, specifically in sapphire and Ti:sapphire, are reviewed.

  20. High-efficiency crystalline silicon technology development (United States)

    Prince, M. B.


    The rationale for pursuing high efficiency crystalline silicon technology research is discussed. Photovoltaic energy systems are reviewed as to their cost effectiveness and their competitiveness with other energy systems. The parameters of energy system life are listed and briefly reviewed.

  1. Metal Organic Framework: Crystalline Stacked Molecular Containers

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 19; Issue 12. Metal Organic Framework: Crystalline Stacked Molecular Containers. Ramanathan Vaidhyanathan. General Article Volume 19 Issue 12 December 2014 pp 1147-1157 ...

  2. Phototropic liquid crystals comprising one component (United States)

    Sobolewska, Anna; Zawada, Joanna; Bartkiewicz, Stanislaw; Galewski, Zbigniew


    Phototropic liquid crystals (PtLC), in which the phase transition can be controlled by the light, are a new class of liquid crystal materials possessing number of potential applications, especially in photonic devices. So far a significant majority of PtLC materials has been realized by the doping a classical liquid crystal with a photochromic dye. Here we report PtLCs comprising a single compound. Liquid-crystalline and photochromic properties have been accomplished in alkylo-alkoxy derivatives of azobenzene. Such compounds show a rich polymorphism which can be controlled by the light. The phenomenon of the photochemical phase transition has been investigated by means of holographic grating recording.

  3. STM, SECPM, AFM and Electrochemistry on Single Crystalline Surfaces. (United States)

    Wolfschmidt, Holger; Baier, Claudia; Gsell, Stefan; Fischer, Martin; Schreck, Matthias; Stimming, Ulrich


    Scanning probe microscopy (SPM) techniques have had a great impact on research fields of surface science and nanotechnology during the last decades. They are used to investigate surfaces with scanning ranges between several 100 mm down to atomic resolution. Depending on experimental conditions, and the interaction forces between probe and sample, different SPM techniques allow mapping of different surface properties. In this work, scanning tunneling microscopy (STM) in air and under electrochemical conditions (EC-STM), atomic force microscopy (AFM) in air and scanning electrochemical potential microscopy (SECPM) under electrochemical conditions, were used to study different single crystalline surfaces in electrochemistry. Especially SECPM offers potentially new insights into the solid-liquid interface by providing the possibility to image the potential distribution of the surface, with a resolution that is comparable to STM. In electrocatalysis, nanostructured catalysts supported on different electrode materials often show behavior different from their bulk electrodes. This was experimentally and theoretically shown for several combinations and recently on Pt on Au(111) towards fuel cell relevant reactions. For these investigations single crystals often provide accurate and well defined reference and support systems. We will show heteroepitaxially grown Ru, Ir and Rh single crystalline surface films and bulk Au single crystals with different orientations under electrochemical conditions. Image studies from all three different SPM methods will be presented and compared to electrochemical data obtained by cyclic voltammetry in acidic media. The quality of the single crystalline supports will be verified by the SPM images and the cyclic voltammograms. Furthermore, an outlook will be presented on how such supports can be used in electrocatalytic studies.

  4. STM, SECPM, AFM and Electrochemistry on Single Crystalline Surfaces

    Directory of Open Access Journals (Sweden)

    Ulrich Stimming


    Full Text Available Scanning probe microscopy (SPM techniques have had a great impact on research fields of surface science and nanotechnology during the last decades. They are used to investigate surfaces with scanning ranges between several 100 mm down to atomic resolution. Depending on experimental conditions, and the interaction forces between probe and sample, different SPM techniques allow mapping of different surface properties. In this work, scanning tunneling microscopy (STM in air and under electrochemical conditions (EC-STM, atomic force microscopy (AFM in air and scanning electrochemical potential microscopy (SECPM under electrochemical conditions, were used to study different single crystalline surfaces in electrochemistry. Especially SECPM offers potentially new insights into the solid-liquid interface by providing the possibility to image the potential distribution of the surface, with a resolution that is comparable to STM. In electrocatalysis, nanostructured catalysts supported on different electrode materials often show behavior different from their bulk electrodes. This was experimentally and theoretically shown for several combinations and recently on Pt on Au(111 towards fuel cell relevant reactions. For these investigations single crystals often provide accurate and well defined reference and support systems. We will show heteroepitaxially grown Ru, Ir and Rh single crystalline surface films and bulk Au single crystals with different orientations under electrochemical conditions. Image studies from all three different SPM methods will be presented and compared to electrochemical data obtained by cyclic voltammetry in acidic media. The quality of the single crystalline supports will be verified by the SPM images and the cyclic voltammograms. Furthermore, an outlook will be presented on how such supports can be used in electrocatalytic studies.

  5. Quantum creep in a highly crystalline two-dimensional superconductor (United States)

    Saito, Yu; Kasahara, Yuichi; Ye, Jianting; Iwasa, Yoshihiro; Nojima, Tsutomu

    Conventional studies on quantum phase transitions, especially on superconductor-insulator or superconductor-metal-insulator transitions have been performed in deposited metallic thin films such as Bismuth or MoGe. Although the techniques of thin films deposition have been considerably improved, unintentional disorder such as impurities and deficiencies, generating the pinning centers, seems to still exist in such systems. The mechanical exfoliated highly crystalline two-dimensional material can be a good candidate to realize a less-disordered 2D superconductor with extremely weak pinning, combined with transfer method or ionic-liquid gating. We report on the quantum metal, namely, magnetic-field-induced metallic state observed in an ion-gated two-dimensional superconductor based on an ultra-highly crystalline layered band insulator, ZrNCl. We found that the superconducting state is extremely fragile against external magnetic fields; that is, zero resistance state immediately disappears, once an external magnetic field switches on. This is because the present system is relatively clean and the pinning potential is extremely weak, which cause quantum tunneling and flux flow of vortices, resulting in metallic ground state.

  6. Waste separation and pretreatment using crystalline silicotitanate ion exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Tadros, M.E.; Miller, J.E. [Sandia National Lab., Albuquerque, NM (United States); Anthony, R.G. [Texas A& M Univ., College Station, TX (United States)


    A new class of inorganic ion exchangers called crystalline silicotitanates (CSTs) has been developed jointly by Sandia National Laboratories and Texas A&M University to selectively remove Cs and other radionuclides from a wide spectrum of radioactive defense wastes. The CST exhibits high selectivity and affinity for Cs and Sr under a wide range of conditions. Tests show it can remove part-per-million concentrations of Cs{sup +} from highly alkaline, high-sodium simulated radioactive waste solutions modeled after those at Hanford, Oak Ridge, and Savannah River. The materials exhibit ion exchange properties based on ionic size selectivity. Specifically, crystalline lattice spacing is controlled to be highly selective for Cs ions even in waste streams containing very high (5 to 10 M) concentrations of sodium. The CST technology is being demonstrated with actual waste at several DOE facilities. The use of inorganic ion exchangers. The inorganics are more resistant to chemical, thermal, and radiation degradation. Their high selectivities result in more efficient operations offering the possibility of a simple single-pass operation. In contrast, regenerable organic ion exchangers require additional processing equipment to handle the regeneration liquids and the eluant with the dissolved Cs.

  7. Zeeman-limited Superconductivity in Crystalline Al Films (United States)

    Adams, Philip; Nam, Hyoundo; Shih, Chin-Kang; Catalani, Gianluigi

    We report the evolution of the Zeeman-limited superconducting phase diagram (PD) in ultra-thin crystalline Al films. Parallel critical field measurements, down to 50 mK, were made across the superconducting tricritical point of epitaxially-grown Al films ranging in thickness from 7 monolayers (ML) to 30 ML. The resulting phase boundaries were compared with the quasi-classical theory of a Zeeman-mediated transition between a homogeneous BCS condensate and a spin polarized Fermi liquid. Films thicker than 20 ML showed good agreement with theory, but thinner films exhibited an anomalous PD that cannot be reconciled within a homogeneous BCS framework. DE-FG02-07ER46420, ONR-N00014-14-1-0330, NSF- DMR-1506678, CIG-618258.

  8. Analysis of XFEL serial diffraction data from individual crystalline fibrils

    Directory of Open Access Journals (Sweden)

    David H. Wojtas


    Full Text Available Serial diffraction data collected at the Linac Coherent Light Source from crystalline amyloid fibrils delivered in a liquid jet show that the fibrils are well oriented in the jet. At low fibril concentrations, diffraction patterns are recorded from single fibrils; these patterns are weak and contain only a few reflections. Methods are developed for determining the orientation of patterns in reciprocal space and merging them in three dimensions. This allows the individual structure amplitudes to be calculated, thus overcoming the limitations of orientation and cylindrical averaging in conventional fibre diffraction analysis. The advantages of this technique should allow structural studies of fibrous systems in biology that are inaccessible using existing techniques.

  9. Large area single crystalline graphene growth on copper foil (United States)

    Jung, Jaehyuck; Phan, Hoang Danh; Changgu, Lee; Graphene Engineering Lab Team

    Graphene synthesis methods using chemical vapor deposition (CVD) have been developed dramatically in these years but still it is challenging to make large size single crystal grains which have similar properties with pristine graphene. Here we report a pita-pocket method of growing large area single crystalline graphene on copper foil. We made holes on top of the closed copper pocket to provide stable gas flow inside of pocket, and copper domains with (111) crystal orientation, which gives an advantage for hexagonal graphene crystal growth, were formed continuously during synthesis. Liquid crystal analysis and electron backscatter diffraction (EBSD) were used to observe the copper crystallographic orientation. Also we compared with a traditional pocket method and an opened flat copper foil method. Graphene from the other methods had poly-crystalinity with different orientation in contrast to graphene from the hole-pocket method.

  10. Synthesis of crystalline gels on a light-induced polymerization 3D printer (Conference Presentation) (United States)

    Gong, Jin; Mao, Yuchen; Miyazaki, Takuya; Zhu, Meifang


    3D printing, also knows as Additive Manufacturing (AM), was first commercialized in 1986, and has been growing at breakneck speed since 2009 when Stratasys' key patent expired. Currently the 3D printing machines coming on the market can be broadly classified into three categories from the material state point of view: plastic filament printers, powder (or pellet) printers, film printers and liquid photopolymer printers. Much of the work in our laboratory revolves around the crystalline gels. We have succeeded in developing them with high toughness, high flexibility, particularly with many functions as shape memory, energy storage, freshness-retaining, water-absorbing, etc. These crystalline gels are synthesized by light-induced radical polymerization that involves light-reactive monomer having the property of curing with light of a sufficient energy to drive the reaction from liquid to solid. Note that the light-induced polymerized 3D printing uses the same principle. To open up the possibilities for broader application of our crystalline functional gels, we are interested in making them available for 3D printing. In this paper, we share the results of our latest research on the 3D printing of crystalline gels on light-induced 3D printers.

  11. Radiocarbon dating of the human eye lens crystallines reveal proteins without carbon turnover throughout life

    DEFF Research Database (Denmark)

    Lynnerup, Niels; Kjeldsen, Henrik; Heegaard, Steffen


    dating is made possible by comparing the (14)C content of the lens crystallines to the so-called bomb pulse, i.e. a plot of the atmospheric (14)C content since the Second World War, when there was a significant increase due to nuclear-bomb testing. Since the change in concentration is significant even...... on a yearly basis this allows very accurate dating. METHODOLOGY/PRINCIPAL FINDINGS: Our results allow us to conclude that the crystalline formation in the lens nucleus almost entirely takes place around the time of birth, with a very small, and decreasing, continuous formation throughout life. The close...... that the eye lens is a soft structure, subjected to almost continuous deformation, due to lens accommodation, yet its most important constituent, the lens crystalline, is never subject to turnover or remodelling once formed. The determination of the (14)C content of various tissues may be used to assess...

  12. A quasimechanism of melt acceleration in the thermal decomposition of crystalline organic solids

    Energy Technology Data Exchange (ETDEWEB)

    Henson, Bryan F [Los Alamos National Laboratory


    It has been know for half a century that many crystalline organic solids undergo an acceleration in the rate of thermal decomposition as the melting temperature is approached. This acceleration terminates at the melting point, exhibiting an Arrhenius-like temperature dependence in the faster decomposition rate from the liquid phase. This observation has been modeled previously using various premelting behaviors based on e.g. freezing point depression induced by decomposition products or solvent impurities. These models do not, however, indicate a mechanism for liquid formation and acceleration which is an inherent function of the bulk thermodynamics of the molecule. Here we show that such an inherent thermodynamic mechanism for liquid formation exists in the form of the so-called quasi-liquid layer at the solid surface. We explore a kinetic mechanism which describes the acceleration of rate and is a function of the free energies of sublimation and vaporization. We construct a differential rate law from these thermodynamic free energies and a normalized progress variable. We further construct a reduced variable formulation of the model which is a simple function of the metastable liquid activity below the melting point, and show that it is applicable to the observed melt acceleration in several common organic crystalline solids. A component of the differential rate law, zero order in the progress variable, is shown to be proportional to the thickness of the quasiliquid layer predicted by a recent thermodynamic theory for this phenomenon. This work therefore serves not only to provide new insight into thermal decomposition in a broad class or organic crystalline solids, but also further validates the underlying thermodynamic nature of the phenomenon of liquid formation on the molecular surface at temperatures below the melting point.

  13. The Landau-de Gennes theory of nematic liquid crystals: Uniaxiality versus Biaxiality

    KAUST Repository

    Majumdar, Apala


    We study small energy solutions within the Landau-de Gennes theory for nematic liquid crystals, subject to Dirichlet boundary conditions. We consider two-dimensional and three-dimensional domains separately. In the two-dimensional case, we establish the equivalence of the Landau-de Gennes and Ginzburg-Landau theory. In the three-dimensional case, we give a new definition of the defect set based on the normalized energy. In the threedimensional uniaxial case, we demonstrate the equivalence between the defect set and the isotropic set and prove the C 1,α-convergence of uniaxial small energy solutions to a limiting harmonic map, away from the defect set, for some 0 < a < 1, in the vanishing core limit. Generalizations for biaxial small energy solutions are also discussed, which include physically relevant estimates for the solution and its scalar order parameters. This work is motivated by the study of defects in liquid crystalline systems and their applications.

  14. Ordering in nematic liquid crystals from NMR cross-polarization ...

    Indian Academy of Sciences (India)


    Nov 27, 2015 ... The measurement of dipolar couplings between nuclei is a convenient way of obtatining directly liquid crystalline ordering through NMR since the coupling is dependent on the average orientation of the dipolar vector in the magnetic field which also aligns the liquid crystal. However, measurement of the ...

  15. Ordering in nematic liquid crystals from NMR cross-polarization ...

    Indian Academy of Sciences (India)

    Abstract. The measurement of dipolar couplings between nuclei is a convenient way of obtatining directly liquid crystalline ordering through NMR since the coupling is dependent on the average orientation of the dipolar vector in the magnetic field which also aligns the liquid crystal. However, measurement of the dipolar ...

  16. Expanding subjectivities

    DEFF Research Database (Denmark)

    Lundgaard Andersen, Linda; Soldz, Stephen


    A major theme in recent psychoanalytic thinking concerns the use of therapist subjectivity, especially “countertransference,” in understanding patients. This thinking converges with and expands developments in qualitative research regarding the use of researcher subjectivity as a tool to understa...

  17. Radiation-Induced Amorphization of Crystalline Ice (United States)

    Fama, M.; Loeffler, M. J.; Raut, U.; Baragiola, R. A.


    We study radiation-induced amorphization of crystalline ice, ana lyzing the resu lts of three decades of experiments with a variety of projectiles, irradiation energy, and ice temperature, finding a similar trend of increasing resistance of amorphization with temperature and inconsistencies in results from different laboratories. We discuss the temperature dependence of amorphization in terms of the 'thermal spike' model. We then discuss the common use of the 1.65 micrometer infrared absorption band of water as a measure of degree of crystallinity, an increasingly common procedure to analyze remote sensing data of astronomical icy bodies. The discussion is based on new, high quality near-infrared refl ectance absorption spectra measured between 1.4 and 2.2 micrometers for amorphous and crystalline ices irradiated with 225 keV protons at 80 K. We found that, after irradiation with 10(exp 15) protons per square centimeter, crystalline ice films thinner than the ion range become fully amorphous, and that the infrared absorption spectra show no significant changes upon further irradiation. The complete amorphization suggests that crystalline ice observed in the outer Solar System, including trans-neptunian objects, may results from heat from internal sources or from the impact of icy meteorites or comets.

  18. Glass-clad single crystalline fiber lasers (United States)

    Lai, C. C.; Hsu, K. Y.; Huang, C. W.; Jheng, D. Y.; Wang, S. C.; Lin, S. L.; Yang, M. H.; Lee, Y. W.; Huang, D. W.; Huang, S. L.


    Yttrium aluminium garnet (YAG) has been widely used as a solid-state laser host because of its superior optical, thermal, mechanical properties, as well as its plurality in hosting active ions with a wide range of ionic radii. Drawing YAG into single crystalline fiber has the potential to further scale up the attainable power level with high mode quality. The recent advancement on the codrawing laser-heated pedestal growth (CDLHPG) technique can produce glass-clad YAG crystalline fibers for laser applications. The drawing speed can reach 10 cm/min for mass production. The CDLHPG technique has shown advantages on transition-metal ion doped YAG and short-fluorescent-lifetime ion doped YAG host. Compared to silica fiber lasers, the crystalline core offers high emission cross section for transition metal ions because of the unique local matrix. The challenges on the development of glass-clad YAG fibers, including core crystallinity, diameter uniformity, dopant segregation, residual strain, post-growth thermal treatment, and the thermal expansion coefficient mismatch between the crystalline core and glass clad are discussed. Chromium, ytterbium, and neodymium ions doped YAG fiber lasers have been successfully achieved with high efficiency and low threshold power. Power scaling with a clad-pump/side-coupling scheme using single clad or double clad YAG fibers is also discussed.

  19. Preparation and catalytic property of a non-crystalline alloy of iron boron with one-dimensional nanostructures (United States)

    Zhu, Yan; Guo, Xiangke; Shen, Yeqian; Mo, Min; Guo, Xuefeng; Ding, Weiping; Chen, Yi


    This paper describes our recent progress on the synthesis and catalytic hydrogenation property of iron-boron non-crystalline alloy with one-dimensional nanostructures, including nanowires, nanorods and nanotubes. The synthesis of one-dimensional nanostructures of iron-boron non-crystalline alloy involves the use of lyotropic liquid crystals of non-ionic-anionic mixed surfactants as templates. The non-ionic surfactants used are Tween 40 (polyoxyethylene sorbitan monopalmitate) and Tween 60 (polyoxyethylene sorbitan monostearate), and the anionic surfactant is CSA (camphorsulfonic acid). The non-crystalline iron-boron nanotubes thus prepared are more effective than the corresponding nanowires and nanorods for the catalytic hydrogenation of m-nitrotoluene. The lyotropic liquid crystals of mixed surfactants provide an effective template for the fabrication of inorganic materials with one-dimensional nanostructures.

  20. Preparation and catalytic property of a non-crystalline alloy of iron-boron with one-dimensional nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Yan; Guo Xiangke; Shen Yeqian; Mo Min; Guo Xuefeng; Ding Weiping; Chen Yi [Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China)


    This paper describes our recent progress on the synthesis and catalytic hydrogenation property of iron-boron non-crystalline alloy with one-dimensional nanostructures, including nanowires, nanorods and nanotubes. The synthesis of one-dimensional nanostructures of iron-boron non-crystalline alloy involves the use of lyotropic liquid crystals of non-ionic-anionic mixed surfactants as templates. The non-ionic surfactants used are Tween 40 (polyoxyethylene sorbitan monopalmitate) and Tween 60 (polyoxyethylene sorbitan monostearate), and the anionic surfactant is CSA (camphorsulfonic acid). The non-crystalline iron-boron nanotubes thus prepared are more effective than the corresponding nanowires and nanorods for the catalytic hydrogenation of m-nitrotoluene. The lyotropic liquid crystals of mixed surfactants provide an effective template for the fabrication of inorganic materials with one-dimensional nanostructures.

  1. Liquid crystals fundamentals

    CERN Document Server

    Singh, Shri


    Liquid crystals are partially ordered systems without a rigid, long-range structure. The study of these materials covers a wide area: chemical structure, physical properties and technical applications. Due to their dual nature - anisotropic physical properties of solids and rheological behavior of liquids - and easy response to externally applied electric, magnetic, optical and surface fields liquid crystals are of greatest potential for scientific and technological applications. The subject has come of age and has achieved the status of being a very exciting interdisciplinary field of scienti

  2. Structural changes in bunched crystalline ion beams

    CERN Document Server

    Bussmann, M; Schätz, T; Habs, D


    Measurements of the spatial distribution of bunched crystalline ion beams in the radio frequency quadrupole storage ring PALLAS are presented for different ratios of the longitudinal and the transverse confinement strengths. The length of highly elongated crystalline ion bunches and its dependence on the bunching voltage is compared to predictions for a one-dimensional ion string and three-dimensional space-charge-dominated beams. The length is found to be considerably shorter than that predicted by the models. Furthermore, the scaling of the length with the bunching voltage is shown to differ from the expected inverse cube root scaling. These differences can partially be attributed to the formation of a mixed crystalline structure. Additionally, a concise mapping of the structural transition from a string to a zig-zag configuration as a function of the ratio of the confinement strengths is presented, which in a similar way deviates from the predictions.

  3. Cooling and heating of crystalline ion beams

    CERN Document Server

    Schramm, U; Bussmann, M; Habs, D


    The crystallization of ion beams has recently been established in the rf quadrupole storage ring PALLAS (PAul Laser CooLing Acceleration System) for laser-cooled sup 2 sup 4 Mg sup + ion beams at an energy of about 1 eV. Yet, unexpectedly sharp constraints had to be met concerning the confinement strength and the longitudinal laser cooling rate. In this paper, related and up to now unseen heating mechanisms are pinpointed for crystalline beams. The weak but inevitable diffusive transverse heating associated with the laser cooling process itself is investigated, possibly allowing the future measurement of the latent heat of the ion crystal. As a function of the beam velocity, the influence of bending shear on the attainability of larger crystalline structures is presented. Finally, rf heating of crystalline beams of different structure is studied for discontinuous cooling.

  4. Influence of drying method on the material properties of nanocellulose I: thermostability and crystallinity (United States)

    Yucheng Peng; Douglas J. Gardner; Yousoo Han; Alper Kiziltas; Zhiyong Cai; Mandla A. Tshabalala


    The effect of drying method on selected material properties of nanocellulose was investigated. Samples of nanofibrillated cellulose (NFC) and cellulose nanocrystals (CNC) were each subjected to four separate drying methods: air-drying, freeze-drying, spray-drying, and supercritical-drying. The thermal stability and crystallinity of the dried nanocellulose were...

  5. Fermi liquids and Luttinger liquids


    Schulz, H. J.; Cuniberti, G.; Pieri, P.


    In these lecture notes, the basic physics of Fermi liquids and Luttinger liquids is presented. Fermi liquids are discussed both from a phenomenological viewpoint, in relation to microscopic approaches, and as renormalization group fixed points. Luttinger liquids are introduced using the bosonization formalism, and their essential differences with Fermi liquids are pointed out. Applications to transport effects, the effect of disorder, quantum spin chains, and spin ladders, both insulating and...

  6. Electronic processes in non-crystalline materials

    CERN Document Server

    Mott, Nevill Francis


    Since the first edition of this highly successful book the field saw many great developments both in experimental and theoretical studies of electrical properties of non-crystalline solids. It became necessary to rewrite nearly the whole book, while the aims of the second edition remained the same: to set out the theoretical concepts, to test them by comparison with experiment for a wide variety of phenomena, and to apply them to non-crystalline materials. Sir Nevill Mott shared the1977 Nobel Prize for Physics, awarded for his research work in this field. The reissue of this book as part of th

  7. Used fuel disposition in crystalline rocks

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hadgu, Teklu [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kalinina, Elena Arkadievna [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jerden, James L. [Argonne National Lab. (ANL), Argonne, IL (United States); Copple, Jacqueline M. [Argonne National Lab. (ANL), Argonne, IL (United States); Cruse, T. [Argonne National Lab. (ANL), Argonne, IL (United States); Ebert, W. [Argonne National Lab. (ANL), Argonne, IL (United States); Buck, E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Eittman, R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Tinnacher, R. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Tournassat, Christophe. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Davis, J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Viswanathan, H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chu, S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dittrich, T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hyman, F. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Karra, S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Makedonska, N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Reimus, P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Zavarin, Mavrik [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Joseph, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)


    The U.S. Department of Energy Office of Nuclear Energy, Office of Fuel Cycle Technology established the Used Fuel Disposition Campaign (UFDC) in fiscal year 2010 (FY10) to conduct the research and development (R&D) activities related to storage, transportation and disposal of used nuclear fuel and high level nuclear waste. The objective of the Crystalline Disposal R&D Work Package is to advance our understanding of long-term disposal of used fuel in crystalline rocks and to develop necessary experimental and computational capabilities to evaluate various disposal concepts in such media.

  8. INEEL Liquid Effluent Inventory

    Energy Technology Data Exchange (ETDEWEB)

    Major, C.A.


    The INEEL contractors and their associated facilities are required to identify all liquid effluent discharges that may impact the environment at the INEEL. This liquid effluent information is then placed in the Liquid Effluent Inventory (LEI) database, which is maintained by the INEEL prime contractor. The purpose of the LEI is to identify and maintain a current listing of all liquid effluent discharge points and to identify which discharges are subject to federal, state, or local permitting or reporting requirements and DOE order requirements. Initial characterization, which represents most of the INEEL liquid effluents, has been performed, and additional characterization may be required in the future to meet regulations. LEI information is made available to persons responsible for or concerned with INEEL compliance with liquid effluent permitting or reporting requirements, such as the National Pollutant Discharge Elimination System, Wastewater Land Application, Storm Water Pollution Prevention, Spill Prevention Control and Countermeasures, and Industrial Wastewater Pretreatment. The State of Idaho Environmental Oversight and Monitoring Program also needs the information for tracking liquid effluent discharges at the INEEL. The information provides a baseline from which future liquid discharges can be identified, characterized, and regulated, if appropriate. The review covered new and removed buildings/structures, buildings/structures which most likely had new, relocated, or removed LEI discharge points, and at least 10% of the remaining discharge points.

  9. Liquid crystal nanocomposites produced by mixtures of hydrogen bonded achiral liquid crystals and functionalized carbon nanotubes (United States)

    Katranchev, B.; Petrov, M.; Keskinova, E.; Naradikian, H.; Rafailov, P. M.; Dettlaff-Weglikowska, U.; Spassov, T.


    The liquid crystalline (LC) nature of alkyloxybenzoic acids is preserved after adding of any mesogenic or non-mesogenic compound through hydrogen bonding. However, this noncovalent interaction provokes a sizable effect on the physical properties as, e. g. melting point and mesomorphic states. In the present work we investigate nanocomposites, prepared by mixture of the eighth homologue of p-n-alkyloxybenzoic acids (8OBA) with single-walled carbon nanotubes (SWCNT) with the purpose to modify the optical properties of the liquid crystal. We exercise optical control on the LC system by inserting SWCNT specially functionalized by carboxylic groups. Since the liquid crystalline state combines order and mobility at the molecular (nanoscale) level, molecular modification can lead to different macroscopical nanocomposite symmetry. The thermal properties of the functionalized nanocomposite are confirmed by DSC analyses. The mechanism of the interaction between surface-treated nanoparticles (functionalized nanotubes) and the liquid crystal 8OBA bent- dimer molecules is briefly discussed.

  10. Evaluating the Type of Light Transmittance in Mono Crystalline, Poly Crystalline and Sapphire Brackets- An Invitro Spectrofluorometer Study. (United States)

    Mohamed, Jauhar P; Kommi, Pradeep Babu; Kumar, M Senthil; Hanumanth; Venkatesan; Aniruddh; Arvinth; Kumar, Arani Nanda


    Most of the patients seek orthodontic treatment to improve the smile, which improves the facial profile by means of fixed appliances i.e., brackets and wires. The brackets are of different types like stainless steel and ceramic. Ceramic brackets were considered as aesthetic appliance which was divided into mono-crystalline, polycrystalline and sapphire brackets. The light transmittance might influence the degree of curing adhesive material in mono crystalline, polycrystalline and sapphire brackets. The aim of the present study was to evaluate the translucency and intensity of three different aesthetic brackets (mono crystalline, poly crystalline and sapphire ceramic brackets) and to determine their influence on shear bond strength of the brackets. The adhesive remnant index was also measured after debonding of the brackets from the tooth surface. Twenty six samples each of monocrystalline, polycrystalline and sapphire brackets (total 78 ceramic brackets) were used for the study. The bracket samples were subjected to optical fluorescence test using spectrofluorometer to measure the intensity of the brackets. Seventy eight extracted premolar teeth were procured and divided into 3 groups. The brackets were then bonded to the tooth using Transbond XT (3M Unitek) light cure composite material and cured with new light cure unit (Light Emitting Diode) of wood pecker company (400-450nm) for 30 seconds, and these samples were subjected to shear bond strength test with Instron Universal Testing Machine (UNITEK-94100) with a load range between 0 to 100 KN with a maximum cross head speed of 0.5mm/min. ARI (Adhesive Remnant Index) scores were evaluated according to Artun and Bergland scoring system using stereomicroscope at 20x magnification. The light absorption values obtained from spectrofluorometeric study were 3300000-3500000 cps for group 1 (monocrystalline ceramic brackets), 6000000-6500000 cps for Group 2 (polycrystalline ceramic brackets) and 2700000 -3000000 cps for

  11. Topological crystalline insulator SnTe nanoribbons (United States)

    Dahal, Bishnu R.; Dulal, Rajendra P.; Pegg, Ian L.; Philip, John


    Topological crystalline insulators are systems in which a band inversion that is protected by crystalline mirror symmetry gives rise to nontrivial topological surface states. SnTe is a topological crystalline insulator. It exhibits p-type conductivity due to Sn vacancies and Te antisites, which leads to high carrier density in the bulk. Thus growth of high quality SnTe is a prerequisite for understanding the topological crystalline insulating behavior. We have grown SnTe nanoribbons using a solution method. The width of the SnTe ribbons varies from 500 nm to 2 μm. They exhibit rock salt crystal structure with a lattice parameter of 6.32 Å. The solution method that we have adapted uses low temperature, so the Sn vacancies can be controlled. The solution grown SnTe nanoribbons exhibit strong semiconducting behavior with an activation energy of 240 meV. This activation energy matches with the calculated band gap for SnTe with a lattice parameter of 6.32 Å, which is higher than that reported for bulk SnTe. The higher activation energy makes the thermal excitation of bulk charges very difficult on the surface. As a result, the topological surfaces will be free from the disturbance caused by the thermal excitations

  12. Crystalline Fullerenes. Round Pegs in Square Holes

    NARCIS (Netherlands)

    Fleming, R.M.; Hessen, B.; Siegrist, T.; Kortan, A.R.; Marsh, P.; Tycko, R.; Dabbagh, G.; Haddon, R.C.


    The fullerenes C60 and C70 act as spherical building blocks in crystalline solids to form a variety of crystal structures. In many cases, the icosahedral molecular symmetry of C60 appears to play little role in determining the crystal structure. In this chapter we discuss our results on the

  13. Quasi-crystalline geometry for architectural structures

    DEFF Research Database (Denmark)

    Wester, Ture; Weinzieri, Barbara

    The quasi-crystal (QC) type of material was discovered in 1983 by Dan Schechtman from Technion, Haifa. This new crystalline structure of material broke totally with the traditional conception of crystals and geometry introducing non-periodic close packing of cells with fivefold symmetry in 3D space...

  14. Donor-hydrogen complexes in crystalline silicon

    NARCIS (Netherlands)

    Liang, Z.N.; Niesen, L; Haas, C; Denteneer, P.J.H.


    Experimental results are presented on the study of Sb-H complexes in crystalline silicon, employing Sb-119 --> Sn-119 source Mossbauer spectroscopy and a low-energy H implantation technique. In addition to a visible component, we observe a large decrease of the Mossbauer intensity associated with

  15. Crystalline amino acids and nitrogen emission

    NARCIS (Netherlands)

    Verstegen, M.W.A.; Jongbloed, A.W.


    Reductions in dietary protein level and supplementation with certain crystalline amino acids is a well-established method of formulating diets to achieve a more ideal amino acid pattern and to reduce nitrogen excretion. Up to 35% reduction in nitrogen excretion may be achieved by supplementing pig

  16. Dynamic Photonic Materials Based on Liquid Crystals (Postprint) (United States)


    in liquid-crystalline side chain polymers. Liquid Crystals, 33, 1421–1427. Atkins , P.W. (1987). Physical chemistry . Oxford: Oxford University Press...Journal of Physical Chemistry C, 114, 7496–7501. Kogelnik,H. (1969). Coupled wave theory for thick hologram gratings. Bell SystemTechnical Journal, 48... Physical Chemistry B, 103, 4212–4217. Lu, S.-Y. & Chien, L.-C. (2007). A polymer-stabilized single-layer color cholesteric liquid crystal display with

  17. Gamma crystallins of the human eye lens. (United States)

    Vendra, Venkata Pulla Rao; Khan, Ismail; Chandani, Sushil; Muniyandi, Anbukkarasi; Balasubramanian, Dorairajan


    Protein crystallins co me in three types (α, β and γ) and are found predominantly in the eye, and particularly in the lens, where they are packed into a compact, plastic, elastic, and transparent globule of proper refractive power range that aids in focusing incoming light on to the retina. Of these, the γ-crystallins are found largely in the nuclear region of the lens at very high concentrations (>400 mg/ml). The connection between their structure and inter-molecular interactions and lens transparency is an issue of particular interest. We review the origin and phylogeny of the gamma crystallins, their special structure involving the use of Greek key supersecondary structural motif, and how they aid in offering the appropriate refractive index gradient, intermolecular short range attractive interactions (aiding in packing them into a transparent ball), the role that several of the constituent amino acid residues play in this process, the thermodynamic and kinetic stability and how even single point mutations can upset this delicate balance and lead to intermolecular aggregation, forming light-scattering particles which compromise transparency. We cite several examples of this, and illustrate this by cloning, expressing, isolating and comparing the properties of the mutant protein S39C of human γS-crystallin (associated with congenital cataract-microcornea), with those of the wild type molecule. In addition, we note that human γ-crystallins are also present in other parts of the eye (e.g., retina), where their functions are yet to be understood. There are several 'crucial' residues in and around the Greek key motifs which are essential to maintain the compact architecture of the crystallin molecules. We find that a mutation that replaces even one of these residues can lead to reduction in solubility, formation of light-scattering particles and loss of transparency in the molecular assembly. Such a molecular understanding of the process helps us construct the

  18. Electro-osmosis in nematic liquid crystals (United States)

    Tovkach, O. M.; Calderer, M. Carme; Golovaty, Dmitry; Lavrentovich, Oleg; Walkington, Noel J.


    We derive a mathematical model of a nematic electrolyte based on a variational formulation of nematodynamics. We verify the model by comparing its predictions to the results of the experiments on the substrate-controlled liquid-crystal-enabled electrokinetics. In the experiments, a nematic liquid crystal confined to a thin planar cell with surface-patterned anchoring conditions exhibits electro-osmotic flows along the "guiding rails" imposed by the spatially varying director. Extending our previous work, we consider a general setup which incorporates dielectric anisotropy of the liquid-crystalline matrix and the full set of nematic viscosities.

  19. High contrast fluorescence patterning in cyanostilbene-based crystalline thin films: crystallization-induced mass flow via a photo-triggered phase transition. (United States)

    Park, Jin Wook; Nagano, Shusaku; Yoon, Seong-Jun; Dohi, Tomoki; Seo, Jangwon; Seki, Takahiro; Park, Soo Young


    A facile and innovative method for the fabrication of highly fluorescent micro-patterns is presented, which operates on the principle of phototriggered phase transition and physical mass migration in the crystalline film of a cyanostilbene-type aggregation-induced enhanced emission (AIEE) molecule ((Z)-2,3-bis(3,4,5-tris(dodecyloxy)phenyl) acrylonitrile) with liquid-crystalline (LC) mesomorphic behavior.


    Indian Academy of Sciences (India)

    Subject Index. Variation of surface electric field during geomagnetic disturbed period at Maitri, Antarctica. 1721. Geomorphology. A simple depression-filling method for raster and irregular elevation datasets. 1653. Decision Support System integrated with Geographic. Information System to target restoration actions in water-.

  1. Micro-Raman spectroscopy for the crystallinity characterization of UHMWPE hip cups run on joint simulators (United States)

    Bertoluzza, A.; Fagnano, C.; Rossi, M.; Tinti, A.; Cacciari, G. L.


    In this work Raman microspectrometry was used to evaluate the crystallinity changes of hip cups made of ultra-high molecular weight polyethylene (UHMWPE). In vitro experiments were carried out using hip joint movement-wear simulators, run for five million cycles in water or bovine calf serum. The hip cups were subjected to mechanical friction with ceramic femoral heads (alumina-zirconia blend). The crystallinity of the polymer hip cups was studied as a function of inner surface position and thickness, from the stressed surface to the unstressed outer one. The Partial Least Square (PLS-l) calibration was used to correlate the Raman spectra with the crystallinity of the polymer measured with DSC calorimetry.

  2. Drying a liquid paint layer

    NARCIS (Netherlands)

    Susanto, H.; van de Fliert, B.W.


    Subject of this study is the free boundary problem of a liquid layer that is dried by evaporation. Using a Stefan type problem, we model the diffusion driven drying of a layer of liquid paint consisting of resin and solvent. The effect of a small perturbation of the flat boundary is considered. We

  3. VUV photoabsorption spectroscopy of amorphous and crystalline sulphur dioxide films (United States)

    Holtom, P. D.; Dawes, A.; Davis, M. P.; Webb, S. M.; Hoffmann, S. V.; Mukerji, R. J.; Mason, N. J.

    Sulphur dioxide, SO2 is one of the simplest sulphur compounds and has been observed widely in the interstellar medium and in the solar system. It has also been observed in the atmospheres of Venus and Io and on the surface of Europa. Gaseous sulphur dioxide has recently been observed for the first time in the extragalactic medium. (Martin et al 1979). Five SO2 transitions detected towards NGC 253 with a total column density of 7 x 1013 cm-1 have been reported. SO2 is also present on Io, in solid, liquid and gaseous form. For example solid phase SO2 was suggested as the source for the 4.05-4.08 μm feature of SO2 seen in the spectrum of Io (Smythe, Nelson & Nash 1979),(Fanale et al 1979). To date most studies of SO2 spectroscopy have been in the gaseous phase with only a few experiments reported on solid SO2. We have used the UV1 beam line on the ASTRID synchrotron based at the University of Aarhus in Denmark to measure the VUV spectrum of condensed phase SO2 over the range of 120 - 350 nm and in the temperature range of 25 - 80 K. (For a full description of our equipment see Dawes, Holtom & Mason 2003). In this poster we report the results of a detailed study of the spectroscopy of solid SO2 in the VUV and UV. At 25 K the VUV spectrum for a fast deposited film (2.8 μm/hr) suggests an amorphous ice layer is formed, in contrast a slow deposition (0.21 μ m/hr) suggests that a more crystalline ice is formed. Annealing (heating of the 25 K fast deposited ice) to 80 K revealed a phase change producing crystalline SO2 ice from the originally amorphous sample. Such spectroscopic features might be used to determine thermal histories of planetary ice. Further details will be presented at the conference.

  4. Interaction of βA3-Crystallin with Deamidated Mutants of αA- and αB-Crystallins.

    Directory of Open Access Journals (Sweden)

    Ekta Tiwary

    Full Text Available Interaction among crystallins is required for the maintenance of lens transparency. Deamidation is one of the most common post-translational modifications in crystallins, which results in incorrect interaction and leads to aggregate formation. Various studies have established interaction among the α- and β-crystallins. Here, we investigated the effects of the deamidation of αA- and αB-crystallins on their interaction with βA3-crystallin using surface plasmon resonance (SPR and fluorescence lifetime imaging microscopy-fluorescence resonance energy transfer (FLIM-FRET methods. SPR analysis confirmed adherence of WT αA- and WT αB-crystallins and their deamidated mutants with βA3-crystallin. The deamidated mutants of αA-crystallin (αA N101D and αA N123D displayed lower adherence propensity for βA3-crystallin relative to the binding affinity shown by WT αA-crystallin. Among αB-crystallin mutants, αB N78D displayed higher adherence propensity whereas αB N146D mutant showed slightly lower binding affinity for βA3-crystallin relative to that shown by WT αB-crystallin. Under the in vivo condition (FLIM-FRET, both αA-deamidated mutants (αA N101D and αA N123D exhibited strong interaction with βA3-crystallin (32±4% and 36±4% FRET efficiencies, respectively compared to WT αA-crystallin (18±4%. Similarly, the αB N78D and αB N146D mutants showed strong interaction (36±4% and 22±4% FRET efficiencies, respectively with βA3-crystallin compared to 18±4% FRET efficiency of WT αB-crystallin. Further, FLIM-FRET analysis of the C-terminal domain (CTE, N-terminal domain (NTD, and core domain (CD of αA- and αB-crystallins with βA3-crystallin suggested that interaction sites most likely reside in the αA CTE and αB NTD regions, respectively, as these domains showed the highest FRET efficiencies. Overall, results suggest that similar to WT αA- and WTαB-crystallins, the deamidated mutants showed strong interactionfor βA3-crystallin

  5. The C-terminal region of alpha-crystallin: involvement in protection against heat-induced denaturation (United States)

    Takemoto, L.; Emmons, T.; Horwitz, J.; Spooner, B. S. (Principal Investigator)


    Recent studies have demonstrated that the alpha-crystallins can protect other proteins against heat-induced denaturation and aggregation. To determine the possible involvement of the C-terminal region in this activity, the alpha-crystallins were subjected to limited tryptic digestion, and the amount of cleavage from the N-terminal and C-terminal regions of the alpha-A and alpha-B crystallin chains was assessed using antisera specific for these regions. Limited tryptic digestion resulted in cleavage only from the C-terminal region of alpha-A crystallin. This trypsin-treated alpha-A crystallin preparation showed a decreased ability to protect proteins from heat-induced aggregation using an in vitro assay. Together, these results demonstrate that the C-terminal region of alpha-A crystallin is important for its ability to protect against heat-induced aggregation, which is consistent with the hypothesis that post-translational changes that are known to occur at the C-terminal region may have significant effects on the ability of alpha-A crystallin to protect against protein denaturation in vivo.

  6. Electromagnetic Processes in strong Crystalline Fields

    CERN Multimedia


    We propose a number of new investigations on aspects of radiation from high energy electron and positron beams (10-300 GeV) in single crystals and amorphous targets. The common heading is radiation emission by electrons and positrons in strong electromagnetic fields, but as the setup is quite versatile, other related phenomena in radiation emission can be studied as well. The intent is to clarify the role of a number of important aspects of radiation in strong fields as e.g. observed in crystals. We propose to measure trident 'Klein-like' production in strong crystalline fields, 'crystalline undulator' radiation, 'sandwich' target phenomena, LPM suppression of pair production as well as axial and planar effects in contributions of spin to the radiation.

  7. Basic research challenges in crystalline silicon photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Werner, J.H. [Max-Planck-Institut fuer Festkoerperforschung, Stuttgart (Germany)


    Silicon is abundant, non-toxic and has an ideal band gap for photovoltaic energy conversion. Experimental world record cells of 24 % conversion efficiency with around 300 {mu}m thickness are only 4 % (absolute) efficiency points below the theoretical Auger recombination-limit of around 28 %. Compared with other photovoltaic materials, crystalline silicon has only very few disadvantages. The handicap of weak light absorbance may be mastered by clever optical designs. Single crystalline cells of only 48 {mu}m thickness showed 17.3 % efficiency even without backside reflectors. A technology of solar cells from polycrystalline Si films on foreign substrates arises at the horizon. However, the disadvantageous, strong activity of grain boundaries in Si could be an insurmountable hurdle for a cost-effective, terrestrial photovoltaics based on polycrystalline Si on foreign substrates. This talk discusses some basic research challenges related to a Si based photovoltaics.

  8. University Crystalline Silicon Photovoltaics Research and Development

    Energy Technology Data Exchange (ETDEWEB)

    Ajeet Rohatgi; Vijay Yelundur; Abasifreke Ebong; Dong Seop Kim


    The overall goal of the program is to advance the current state of crystalline silicon solar cell technology to make photovoltaics more competitive with conventional energy sources. This program emphasizes fundamental and applied research that results in low-cost, high-efficiency cells on commercial silicon substrates with strong involvement of the PV industry, and support a very strong photovoltaics education program in the US based on classroom education and hands-on training in the laboratory.

  9. Controlled synthesis of single-crystalline graphene

    Directory of Open Access Journals (Sweden)

    Wang Xueshen


    Full Text Available This paper reports the controlled synthesis of single-crystalline graphene on the back side of copper foil using CH4 as the precursor. The influence of growth time and the pressure ratio of CH4/H2 on the structure of graphene are examined. An optimized polymer-assisted method is used to transfer the synthesized graphene onto a SiO2/Si substrate. Scanning electron microscopy and Raman spectroscopy are used to characterize the graphene.

  10. Directed Line Liquids (United States)

    Kamien, Randall David

    This thesis is devoted to the study of ensembles of dense directed lines. These lines are principally to be thought of as polymers, though they also have the morphology of flux lines in high temperature superconductors, strings of colloidal spheres in electrorheological fluids and the world lines of quantum mechanical bosons. We first study nematic polymers dissolved in a nematic solvent. We show that in the dense phase nematic polymers interacting directly through excluded volume and indirectly through nematic solvent fluctuations are, at long wavelengths, identical to nematic polymers in an isotropic solvent, interacting through, again, excluded volume as well as their nematic degrees of freedom. By including the effects of free ends we study ferro- and electrorheological fluids and finite chain length polymers. In the dilute phase, near the transition to the semi-dilute phase, a renormalization group treatment is performed, in the physical and critical dimension 3. For sufficiently dilute systems we find logarithmic corrections to polymer wandering, predicted by de Gennes. However, at higher densities, the logarithmic enhancement is suppressed, and the polymers execute conventional random walks along the preferred axis. We then study the isotropic to nematic transition in this same system of liquid-crystalline polymers. Using the replica technique introduced by de Gennes to study isotropic polymers, we formulate a fully isotropic theory of liquid-crystalline polymers dissolved in a liquid crystal matrix. The first order transition from isotropic to nematic ordering occurs, and leads to the original directed polymer theory previously studied. In agreement with physical expectations, the nematic ordering temperature is depressed by polymerization. Finally, we go back to directed systems, in this case directed by an explicit symmetry violation instead of spontaneously. We discuss how directed polymer melts, string-like formations in electrorheological and ferro

  11. Multiresponsive self-assembled liquid crystals with azobenzene groups. (United States)

    Xu, Miao; Chen, Liqin; Zhou, Yifeng; Yi, Tao; Li, Fuyou; Huang, Chunhui


    An optical and electric field-responsive self-assembled complex containing nitril azobenzene groups and 1,3,5-triazine-2,4-diamine was obtained and characterized. Both the azobenzene precursor and the complex form a liquid-crystalline phase in a certain temperature range. The transition temperature from crystalline phase to liquid-crystalline mesophase was obviously decreased in the complex by the self-assembling. The self-assembled liquid crystals revealed good response to both stimuli of light irradiation and electric field, and the induced molecular orientation could be held even after the removal of the stimuli. The structural and mechanical investigation proved that the formation of hydrogen bonds and assembly-induced molecular dipolar change contributed to the multiresponding action. This kind of self-assembled complex thus has potential applications in imaging and data storage.

  12. Effect of polylactic acid crystallinity on its electret properties (United States)

    Guzhova, A. A.; Galikhanov, M. F.; Kuznetsova, N. V.; Petrov, V. A.; Khairullin, R. Z.


    Electret properties of the polylactic acid films with different degree of crystallinity due to different cooling and annealing conditions were studied. Samples with the higher degree of crystallinity showed more stable electret characteristics resulting from amorphous-crystalline interface boundary growth and capturing bigger amount of injected charge carriers by volume energy traps.

  13. Ageing and vision: structure, stability and function of lens crystallins.

    NARCIS (Netherlands)

    Bloemendal, H.; Jong, W.W.W. de; Jaenicke, R.; Lubsen, N.H.; Slingsby, C.; Tardieu, A.


    The alpha-, beta- and gamma-crystallins are the major protein components of the vertebrate eye lens, alpha-crystallin as a molecular chaperone as well as a structural protein, beta- and gamma-crystallins as structural proteins. For the lens to be able to retain life-long transparency in the absence

  14. The Thermodynamic Scale of Inorganic Crystalline Metastability (United States)

    Sun, Wenhao; Dacek, Stephen; Ong, Shyue Ping; Hautier, Geoffroy; Jain, Anubhav; Richards, William; Gamst, Anthony; Persson, Kristin; Ceder, Gerbrand; Materials Project Team

    The space of metastable materials offers promising new design opportunities for next-generation technological materials such as complex oxides, semiconductors, pharmaceuticals, steels and beyond. Although metastable phases are ubiquitous in both nature and technology, only a heuristic understanding of their underlying thermodynamics exists. Here we report a large-scale data-mining study of the Materials Project, a high-throughput database of DFT-calculated energetics of ICSD structures, to explicitly quantify the thermodynamic scale of metastability for 29,902 observed inorganic crystalline phases. We reveal the influence of chemistry and composition on the accessible thermodynamic range of crystalline metastability for polymorphic and phase-separating compounds, yielding new physical insights that can guide the design of novel metastable materials. We further assert that not all low-energy metastable compounds can necessarily be synthesized, and propose a principle of ``remnant metastability'' - that observable metastable crystalline phases are generally remnants of thermodynamic conditions where they were once the lowest free-energy phase. DOE Contract DE-AC02-05CH11231 and Contract no. UGA-0-41029-16/ER392000.

  15. Crystalline to amorphous transformation in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Cheruvu, S.M.


    In the present investigation, an attempt was made to understand the fundamental mechanism of crystalline-to-amorphous transformation in arsenic implanted silicon using high resolution electron microscopy. A comparison of the gradual disappearance of simulated lattice fringes with increasing Frenkel pair concentration with the experimental observation of sharp interfaces between crystalline and amorphous regions was carried out leading to the conclusion that when the defect concentration reaches a critical value, the crystal does relax to an amorphous state. Optical diffraction experiments using atomic models also supported this hypothesis. Both crystalline and amorphous zones were found to co-exist with sharp interfaces at the atomic level. Growth of the amorphous fraction depends on the temperature, dose rate and the mass of the implanted ion. Preliminary results of high energy electron irradiation experiments at 1.2 MeV also suggested that clustering of point defects occurs near room temperature. An observation in a high resolution image of a small amorphous zone centered at the core of a dislocation is presented as evidence that the nucleation of an amorphous phase is heterogeneous in nature involving clustering or segregation of point defects near existing defects.

  16. Molecular Sensing by Nanoporous Crystalline Polymers

    Directory of Open Access Journals (Sweden)

    Vincenzo Venditto


    Full Text Available Chemical sensors are generally based on the integration of suitable sensitive layers and transducing mechanisms. Although inorganic porous materials can be effective, there is significant interest in the use of polymeric materials because of their easy fabrication process, lower costs and mechanical flexibility. However, porous polymeric absorbents are generally amorphous and hence present poor molecular selectivity and undesired changes of mechanical properties as a consequence of large analyte uptake. In this contribution the structure, properties and some possible applications of sensing polymeric films based on nanoporous crystalline phases, which exhibit all identical nanopores, will be reviewed. The main advantages of crystalline nanoporous polymeric materials with respect to their amorphous counterparts are, besides a higher selectivity, the ability to maintain their physical state as well as geometry, even after large guest uptake (up to 10–15 wt%, and the possibility to control guest diffusivity by controlling the orientation of the host polymeric crystalline phase. The final section of the review also describes the ability of suitable polymeric films to act as chirality sensors, i.e., to sense and memorize the presence of non-racemic volatile organic compounds.

  17. The thermodynamic scale of inorganic crystalline metastability. (United States)

    Sun, Wenhao; Dacek, Stephen T; Ong, Shyue Ping; Hautier, Geoffroy; Jain, Anubhav; Richards, William D; Gamst, Anthony C; Persson, Kristin A; Ceder, Gerbrand


    The space of metastable materials offers promising new design opportunities for next-generation technological materials, such as complex oxides, semiconductors, pharmaceuticals, steels, and beyond. Although metastable phases are ubiquitous in both nature and technology, only a heuristic understanding of their underlying thermodynamics exists. We report a large-scale data-mining study of the Materials Project, a high-throughput database of density functional theory-calculated energetics of Inorganic Crystal Structure Database structures, to explicitly quantify the thermodynamic scale of metastability for 29,902 observed inorganic crystalline phases. We reveal the influence of chemistry and composition on the accessible thermodynamic range of crystalline metastability for polymorphic and phase-separating compounds, yielding new physical insights that can guide the design of novel metastable materials. We further assert that not all low-energy metastable compounds can necessarily be synthesized, and propose a principle of 'remnant metastability'-that observable metastable crystalline phases are generally remnants of thermodynamic conditions where they were once the lowest free-energy phase.

  18. Stimuli-responsive photoluminescent liquid crystals. (United States)

    Yamane, Shogo; Tanabe, Kana; Sagara, Yoshimitsu; Kato, Takashi


    We describe mechanochromic and thermochromic photoluminescent liquid crystals. In particular, mechanochromic photoluminescent liquid crystals found recently, which are new stimuli-responsive materials are reported. For example, photoluminescent liquid crystals having bulky dendritic moieties with long alkyl chains change their photoluminescent colors by mechanical stimuli associated with isothermal phase transitions. The photoluminescent properties of molecular assemblies depend on their assembled structures. Therefore, controlling the structures of molecular assemblies with external stimuli leads to the development of stimuli-responsive luminescent materials. Mechanochromic photoluminescent properties are also observed for a photoluminescent metallomesogen and a liquid-crystalline polymer. We also show thermochromic photoluminescent liquid crystals based on origo-(p-phenylenevinylene) and anthracene moieties and a thermochromic photoluminescent metallocomplex.

  19. Liquid Ventilation

    Directory of Open Access Journals (Sweden)

    Qutaiba A. Tawfic


    Full Text Available Mammals have lungs to breathe air and they have no gills to breath liquids. When the surface tension at the air-liquid interface of the lung increases, as in acute lung injury, scientists started to think about filling the lung with fluid instead of air to reduce the surface tension and facilitate ventilation. Liquid ventilation (LV is a technique of mechanical ventilation in which the lungs are insufflated with an oxygenated perfluorochemical liquid rather than an oxygen-containing gas mixture. The use of perfluorochemicals, rather than nitrogen, as the inert carrier of oxygen and carbon dioxide offers a number of theoretical advantages for the treatment of acute lung injury. In addition, there are non-respiratory applications with expanding potential including pulmonary drug delivery and radiographic imaging. The potential for multiple clinical applications for liquid-assisted ventilation will be clarified and optimized in future. Keywords: Liquid ventilation; perfluorochemicals; perfluorocarbon; respiratory distress; surfactant.

  20. Electrical transport in crystalline phase change materials

    Energy Technology Data Exchange (ETDEWEB)

    Woda, Michael


    In this thesis, the electrical transport properties of crystalline phase change materials are discussed. Phase change materials (PCM) are a special class of semiconducting and metallic thin film alloys, typically with a high amount of the group five element antimony or the group six element tellurium, such as Ge{sub 2}Sb{sub 2}Te{sub 5}. The unique property portfolio of this material class makes it suitable for memory applications. PCMs reveal fast switching between two stable room-temperature phases (amorphous and crystalline) realized by optical laser or electrical current pulses in memory devices. Additionally, a pronounced property contrast in form of optical reflectivity and electrical conductivity between the amorphous and crystalline phase is the characteristic fingerprint of PCMs. The emerging electrical solid state memory PCRAM is a very promising candidate to replace Flash memory in the near future or to even become a universal memory, which is non-volatile and shows the speed and cyclability of DRAM. One of the main technological challenges is the switching process into the amorphous state, which is the most power demanding step. In order to reduce the switching power, the crystalline resistivity needs to be increased at a given voltage. Thus understanding and tayloring of this property is mandatory. In this work, first the technological relevance, i.e. optical and electrical memory concepts based on PCMs are introduced. Subsequently a description of the physical properties of PCMs in four categories is given. Namely, structure, kinetics, optical properties and electrical properties are discussed. Then important recent developments such as the identification of resonant bonding in crystalline PCMs and a property predicting coordination scheme are briefly reviewed. The following chapter deals with the theoretical background of electrical transport, while the next chapter introduces the experimental techniques: Sputtering, XRR, XRD, DSC, thermal annealing

  1. Thin Crystalline Gallium Arsenide Optoelectronic Devices (United States)

    Patkar, Mahesh Pandharinath


    The numerous existing and developing applications for two closely related devices, III-V light emitting diode (LEDs) and solar cells, demand improved device efficiencies. Removing the substrate should increase the efficiency of both LEDs and solar cells by eliminating the absorption losses in the substrate. We have used the phenomenon of photon recycling in thin-crystalline device geometries to enhance efficiencies of LEDs and solar cells. GaAs LEDs were fabricated and removed from the substrate by the epitaxial lift-off process. Devices with and without an underlying GaAs substrate were then characterized by optical and electrical measurements. Efficiency enhancements of up to a factor of six were achieved. By carefully analyzing the electrical and optical measurements, we demonstrate that the device operation can be explained in terms of accepted theories for radiative recombination and photon recycling which supports our hypothesis that the efficiency enhancement is due to photon recycling in the thin-crystalline device structure. Electrical and optical characterization of ELO LEDs is also shown to be a convenient diagnostic tool for examining recombination losses in thin-crystalline solar cells. Thin crystalline solar cells were fabricated and characterized by I-V and QE measurements. Alloyed ohmic contacts are used extensively for GaAs devices. However, alloyed contacts produce rough interfaces that do not make good reflectors needed for many optoelectronic devices. Non-alloyed ohmic contacts to optoelectronic devices could make good reflectors, if one uses highly reflective metal like Au to make an ohmic contact. Ex-situ non-alloyed contacts to n-GaAs were made by using low temperature molecular beam epitaxy. Ag and Ti/Au contacts to this structure exhibited specific contact resistivities of mid 10^{-7} Omega-cm^2. Low temperature molecular beam epitaxy of GaAs with high concentrations of Be followed by an anneal under As over pressure was used to minimize

  2. Generation of crystalline silica from sugarcane burning. (United States)

    Le Blond, Jennifer S; Horwell, Claire J; Williamson, Ben J; Oppenheimer, Clive


    Sugarcane leaves contain amorphous silica, which may crystallise to form crystalline silica polymorphs (cristobalite or quartz), during commercial sugarcane harvesting where sugarcane plants are burned. Respirable airborne particulate containing these phases may present an occupational health hazard. Following from an earlier pilot study (J. S. Le Blond, B. J. Williamson, C. J. Horwell, A. K. Monro, C. A. Kirk and C. Oppenheimer, Atmos. Environ., 2008, 42, 5558-5565) in which experimental burning of sugarcane leaves yielded crystalline silica, here we report on actual conditions during sugarcane burning on commercial estates, investigate the physico-chemical properties of the cultivated leaves and ash products, and quantify the presence of crystalline silica. Commercially grown raw sugarcane leaf was found to contain up to 1.8 wt% silica, mostly in the form of amorphous silica bodies (with trace impurities e.g., Al, Na, Mg), with only a small amount of quartz. Thermal images taken during several pre-harvest burns recorded temperatures up to 1056 degrees C, which is sufficient for metastable cristobalite formation. No crystalline silica was detected in airborne particulate from pre-harvest burning, collected using a cascade impactor. The sugarcane trash ash formed after pre-harvest burning contained between 10 and 25 wt% SiO(2), mostly in an amorphous form, but with up to 3.5 wt% quartz. Both quartz and cristobalite were identified in the sugarcane bagasse ash (5-15 wt% and 1-3 wt%, respectively) formed in the processing factory. Electron microprobe analysis showed trace impurities of Mg, Al and Fe in the silica particles in the ash. The absence of crystalline silica in the airborne emissions and lack of cristobalite in trash ash suggest that high temperatures during pre-harvest burning were not sustained long enough for cristobalite to form, which is supported by the presence of low temperature sylvite and calcite in the residual ash. The occurrence of quartz and

  3. Definition of Liquidation Property Value

    Directory of Open Access Journals (Sweden)

    Vytautas Lingaitis


    Full Text Available The article examines the interrelation of market and liquidation value of the appraisal subject. It was established that the approach of “break-even” sale of a subject at liquidation value, which is predominating in the literature sources, shows the results essentially different from the ratio of the prices of free and accelerated sales that can be observed on the market. The article offers an alternative approach to definition of market value coefficient, which considers switching to liquidation value. This approach is based on functional dependence of the coefficient on the ratio of limited and unlimited period of exposition.

  4. Subsidizing Liquidity

    DEFF Research Database (Denmark)

    Malinova, Katya; Park, Andreas


    Facing increased competition over the last decade, many stock exchanges changed their trading fees to maker-taker pricing, an incentive scheme that rewards liquidity suppliers and charges liquidity demanders. Using a change in trading fees on the Toronto Stock Exchange, we study whether and why...... the breakdown of trading fees between liquidity demanders and suppliers matters. Posted quotes adjust after the change in fee composition, but the transaction costs for liquidity demanders remain unaffected once fees are taken into account. However, as posted bid-ask spreads decline, traders (particularly...... retail) use aggressive orders more frequently, and adverse selection costs decrease....

  5. Applications of high resolution NMR to geochemistry: crystalline, glass, and molten silicates

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, E.


    The nuclear spin interactions and the associated quantum mechanical dynamics which are present in solid state NMR are introduced. A brief overview of aluminosilicate structure is presented and crystalline structure is then reviewed, with emphasis on the contributions made by /sup 29/Si NMR spectroscopy. The local structure of glass aluminosilicates as observed by NMR, is presented with analysis of the information content of /sup 29/Si spectra. A high-temperature (to 1300/sup 0/C) NMR spectroscopic investigation of the local environment and dynamics of molecular motion in molten aluminosilicates is described. A comparison is made of silicate liquid, glass, and crystalline local structure. The atomic and molecular motions present in a melt are investigated through relaxation time (T/sub 1/ and T/sub 2/) measurements as a function of composition and temperature for /sup 23/Na and /sup 29/Si.

  6. Crystallinity in starch plastics: consequences for material properties. (United States)

    van Soest, J J; Vliegenthart, J F


    The processing of starches with biodegradable additives has made biodegradable plastics suitable for a number of applications. Starch plastics are partially crystalline as a result of residual crystallinity and the recrystallization of amylose and amylopectin. Such crystallinity is a key determinant of the product's properties. This article describes the influence of processing and storage conditions on starch crystallinity and offers possible explanations for the various properties of starch plastics, in particular for the problems associated with ageing, in terms of the different crystalline structures.

  7. Indomethacin nanocrystals prepared by different laboratory scale methods: effect on crystalline form and dissolution behavior (United States)

    Martena, Valentina; Censi, Roberta; Hoti, Ela; Malaj, Ledjan; Di Martino, Piera


    The objective of this study is to select very simple and well-known laboratory scale methods able to reduce particle size of indomethacin until the nanometric scale. The effect on the crystalline form and the dissolution behavior of the different samples was deliberately evaluated in absence of any surfactants as stabilizers. Nanocrystals of indomethacin (native crystals are in the γ form) (IDM) were obtained by three laboratory scale methods: A (Batch A: crystallization by solvent evaporation in a nano-spray dryer), B (Batch B-15 and B-30: wet milling and lyophilization), and C (Batch C-20-N and C-40-N: Cryo-milling in the presence of liquid nitrogen). Nanocrystals obtained by the method A (Batch A) crystallized into a mixture of α and γ polymorphic forms. IDM obtained by the two other methods remained in the γ form and a different attitude to the crystallinity decrease were observed, with a more considerable decrease in crystalline degree for IDM milled for 40 min in the presence of liquid nitrogen. The intrinsic dissolution rate (IDR) revealed a higher dissolution rate for Batches A and C-40-N, due to the higher IDR of α form than γ form for the Batch A, and the lower crystallinity degree for both the Batches A and C-40-N. These factors, as well as the decrease in particle size, influenced the IDM dissolution rate from the particle samples. Modifications in the solid physical state that may occur using different particle size reduction treatments have to be taken into consideration during the scale up and industrial development of new solid dosage forms.

  8. Indomethacin nanocrystals prepared by different laboratory scale methods: effect on crystalline form and dissolution behavior

    Energy Technology Data Exchange (ETDEWEB)

    Martena, Valentina; Censi, Roberta [University of Camerino, School of Pharmacy (Italy); Hoti, Ela; Malaj, Ledjan [University of Tirana, Department of Pharmacy (Albania); Di Martino, Piera, E-mail: [University of Camerino, School of Pharmacy (Italy)


    The objective of this study is to select very simple and well-known laboratory scale methods able to reduce particle size of indomethacin until the nanometric scale. The effect on the crystalline form and the dissolution behavior of the different samples was deliberately evaluated in absence of any surfactants as stabilizers. Nanocrystals of indomethacin (native crystals are in the {gamma} form) (IDM) were obtained by three laboratory scale methods: A (Batch A: crystallization by solvent evaporation in a nano-spray dryer), B (Batch B-15 and B-30: wet milling and lyophilization), and C (Batch C-20-N and C-40-N: Cryo-milling in the presence of liquid nitrogen). Nanocrystals obtained by the method A (Batch A) crystallized into a mixture of {alpha} and {gamma} polymorphic forms. IDM obtained by the two other methods remained in the {gamma} form and a different attitude to the crystallinity decrease were observed, with a more considerable decrease in crystalline degree for IDM milled for 40 min in the presence of liquid nitrogen. The intrinsic dissolution rate (IDR) revealed a higher dissolution rate for Batches A and C-40-N, due to the higher IDR of {alpha} form than {gamma} form for the Batch A, and the lower crystallinity degree for both the Batches A and C-40-N. These factors, as well as the decrease in particle size, influenced the IDM dissolution rate from the particle samples. Modifications in the solid physical state that may occur using different particle size reduction treatments have to be taken into consideration during the scale up and industrial development of new solid dosage forms.

  9. Solution properties of γ-crystallins: Hydration of fish and mammal γ-crystallins (United States)

    Zhao, Huaying; Chen, Yingwei; Rezabkova, Lenka; Wu, Zhengrong; Wistow, Graeme; Schuck, Peter


    Lens γ crystallins are found at the highest protein concentration of any tissue, ranging from 300 mg/mL in some mammals to over 1000 mg/mL in fish. Such high concentrations are necessary for the refraction of light, but impose extreme requirements for protein stability and solubility. γ-crystallins, small stable monomeric proteins, are particularly associated with the lowest hydration regions of the lens. Here, we examine the solvation of selected γ-crystallins from mammals (human γD and mouse γS) and fish (zebrafish γM2b and γM7). The thermodynamic water binding coefficient B1 could be probed by sucrose expulsion, and the hydrodynamic hydration shell of tightly bound water was probed by translational diffusion and structure-based hydrodynamic boundary element modeling. While the amount of tightly bound water of human γD was consistent with that of average proteins, the water binding of mouse γS was found to be relatively low. γM2b and γM7 crystallins were found to exhibit extremely low degrees hydration, consistent with their role in the fish lens. γM crystallins have a very high methionine content, in some species up to 15%. Structure-based modeling of hydration in γM7 crystallin suggests low hydration is associated with the large number of surface methionine residues, likely in adaptation to the extremely high concentration and low hydration environment in fish lenses. Overall, the degree of hydration appears to balance stability and tissue density requirements required to produce and maintain the optical properties of the lens in different vertebrate species. PMID:24282025

  10. Bioequivalence study between a fixed-dose single-pill formulation of nebivolol plus hydrochlorothiazide and separate formulations in healthy subjects using high-performance liquid chromatography coupled to tandem mass spectrometry. (United States)

    Vespasiano, Celso Francisco Pimentel; Laurito, Tiago Luders; Iwamoto, Renan Donomae; Moreno, Ronilson Agnaldo; Mendes, Gustavo D; De Nucci, Gilberto


    Systemic arterial hypertension is a major risk factor for cerebrovascular disease. Therefore, adequate control of blood pressure is of enormous importance. One of the many fixed-dose single-pill antihypertensive formulations available on the market is the combination of nebivolol and hydrochlorothiazide. The objective of this study was to develop two distinct high-performance liquid chromatography coupled to tandem mass spectrometry methods to simultaneously quantify nebivolol and hydrochlorothiazide in human plasma. The methods were employed in a bioequivalence study, the first assay involving a nebivolol fixed-dose single-pill formulation based on healthy Brazilian volunteers. Nebilet HCT™ (nebivolol 5 mg + hydrochlorothiazide 12.5 mg tablet, manufactured by Menarini) was the test formulation. The reference formulations were Nebilet™ (nebivolol 5 mg tablet, manufactured by Menarini) and Clorana™ (hydrochlorothiazide 25 mg tablet, manufactured by Sanofi). For both analytes, liquid-liquid extraction was employed for sample preparation and the chromatographic run time was 3.5 min. The limits of quantification validated were 0.02 ng/mL for nebivolol and 1 ng/mL for hydrochlorothiazide. Since the 90% CI for Cmax , AUC(0-last) and AUC(0-inf) individual test/reference ratios were within the 80-125% interval indicative of bioequivalence, it was concluded that Nebilet HCT™ is bioequivalent to Nebilet™ and Clorana™. Copyright © 2016 John Wiley & Sons, Ltd.

  11. On the origin of anisotropic lithiation in crystalline silicon over germanium: A first principles study

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Chia-Yun [Materials Science and Engineering Program, University of Texas at Austin, Austin, TX 78712 (United States); Hwang, Gyeong S., E-mail: [Materials Science and Engineering Program, University of Texas at Austin, Austin, TX 78712 (United States); Department of Chemical Engineering, University of Texas at Austin, Austin, TX 78712 (United States)


    Graphical abstract: - Highlights: • We examine the underlying reasons for the anisotropic lithiation of Si over Ge in the crystalline phase. • Crystalline Si is lithiated in a layer-by-layer fashion, yielding a sharp amorphous–crystalline interface. • Lithiated c-Ge exhibits a graded lithiation front, which proceeds much faster than that in c-Si. • Lithiation behavior tends to be subject to the stiffness and dynamics of the host matrix. • We reveal the origin and extended impacts of the anisotropic Si vs. isotropic Ge lithiation. - Abstract: Silicon (Si) and germanium (Ge) are both recognized as a promising anode material for high-energy lithium-ion batteries. Si is abundant and best known for its superior gravimetric energy storage capacity, while Ge exhibits faster charge/discharge rates and better capacity retention. Recently, it was discovered that Si lithiation exhibits strong orientation dependence while Ge lithiation proceeds isotropically, although they have the same crystalline structure. To better understand the underlying reasons behind these distinctive differences, we examine and compare the lithiation behaviors at the Li{sub 4}Si/c-Si(1 1 0) and Li{sub 4}Ge/c-Ge(1 1 0) model systems using ab initio molecular dynamics simulations. In comparison to lithiated c-Si, where a sharp amorphous–crystalline interface remains and advances rather slowly, lithiated c-Ge tends to loose its crystallinity rapidly, resulting in a graded lithiation front of fast propagation speed. Analysis of the elastic responses and dynamics of the host Si and Ge lattices clearly demonstrate that from the beginning of the lithiation process, Ge lattice responds with more significant weakening as compared to the rigid Si lattice. Moreover, the more flexible Ge lattice is found to undergo facile atomic rearrangements during lithiation, overshadowing the original crystallographic characteristic. These unique properties of Ge thereby contribute synergistically to the rapid

  12. Health effects of occupational exposure to crystalline silica in the light of current research results. (United States)

    Maciejewska, Aleksandra


    Crystalline silica is commonly found in the work environment. Possible health effects of occupational exposure continue to be the subject of extensive research. The aim of this paper was to analyze the recent findings concerning the health effects of exposure to crystalline silica, taking into account different levels of exposure. This work is based on the relevant information from the papers retrieved from the following databases: EBSCO, Scopus, ScienceDirect, and Web of Science, using the following keywords: crystalline silica, quartz, health effects. The review of the results confirms the multi-faceted harmful effects of crystalline silica. Prolonged occupational exposure, apart from silicosis and non-cancer respiratory diseases, may also result in the development of lung cancer, and autoimmune and chronic kidney diseases, the pathogenesis, which has not been completely explained yet. The exposure to the crystalline silica at concentrations close to the current occupational exposure limit value does not exclude the risk of the following pathologies: silicosis, lung cancer, other lung diseases and renal diseases. It is not feasible to completely eliminate the crystalline silica dust from the work environment. The best way to reduce the health effects of the exposure is to minimize the concentrations of silica dust. Further progress in clarifying the true mechanisms of interaction between silica dust and lung cells, the determination of the importance of surface properties of the silica particles in the pathogenic processes and explaining the effects of co-morbid dust in the work environment may help to prevent the harmful effects of silica dust.

  13. Biomimetic processing of oriented crystalline ceramic layers

    Energy Technology Data Exchange (ETDEWEB)

    Cesarano, J.; Shelnutt, J.A.


    The aim of this project was to develop the capabilities for Sandia to fabricate self assembled Langmuir-Blodgett (LB) films of various materials and to exploit their two-dimensional crystalline structure to promote the growth of oriented thin films of inorganic materials at room temperature. This includes the design and synthesis of Langmuir-active (amphiphilic) organic molecules with end groups offering high nucleation potential for various ceramics. A longer range goal is that of understanding the underlying principles, making it feasible to use the techniques presented in this report to fabricate unique oriented films of various materials for electronic, sensor, and membrane applications. Therefore, whenever possible, work completed in this report was completed with the intention of addressing the fundamental phenomena underlying the growth of crystalline, inorganic films on template layers of highly organized organic molecules. This problem was inspired by biological processes, which often produce exquisitely engineered structures via templated growth on polymeric layers. Seashells, for example, exhibit great toughness owing to their fine brick-and-mortar structure that results from templated growth of calcium carbonate on top of layers of ordered organic proteins. A key goal in this work, therefore, is to demonstrate a positive correlation between the order and orientation of the template layer and that of the crystalline ceramic material grown upon it. The work completed was comprised of several parallel efforts that encompassed the entire spectrum of biomimetic growth from solution. Studies were completed on seashells and the mechanisms of growth for calcium carbonate. Studies were completed on the characterization of LB films and the capability developed for the in-house fabrication of these films. Standard films of fatty acids were studied as well as novel polypeptides and porphyrins that were synthesized.

  14. Crystalline silicotitanates for cesium/strontium removal

    Energy Technology Data Exchange (ETDEWEB)

    Brown, N.; Miller, J.; Sherman, J.


    A new class of inorganic ion exchangers called crystalline silicotitanates (CST) has been developed that exhibits very high selectivity for cesium and strontium in the highly alkaline radioactive wastes at the Hanford Site and other DOE sites. Tests have also shown that CSTs have high selectivity for cesium in acidic and neutral solutions. The ESP is supporting an effort at Sandia National Laboratories and Texas A & M University to further develop and characterize the important chemical and physical properties that will determine the applicability of CST to radioactive waste treatment at Hanford and other DOE facilities.

  15. Vibrational dynamics of crystalline L-alanine

    Energy Technology Data Exchange (ETDEWEB)

    Bordallo, H.N.; Eckert, J. [Los Alamos National Lab., NM (United States); Barthes, M. [Univ. Montpellier II (France)


    The authors report a new, complete vibrational analysis of L-alanine and L-alanine-d{sub 4} which utilizes IINS intensities in addition to frequency information. The use of both isotopomers resulted in a self-consistent force field for and assignment of the molecular vibrations in L-alanine. Some details of the calculation as well as a comparison of calculated and observed IINS spectra are presented. The study clarifies a number of important issues on the vibrational dynamics of this molecule and presents a self-consistent force field for the molecular vibrations in crystalline L-alanine.

  16. Structural properties of Y2O3–Al2O3 liquids and glasses: An overview

    Energy Technology Data Exchange (ETDEWEB)

    Wilding, Martin C.; Wilson, Mark; McMillan, Paul F.; Benmore, Chris J.; Weber, J. K.R.; Deschamps, Thierry; Champagnon, Bernard


    Liquids in the system Y2O3- Al2O3 have been the subject of considerable study because of the reported occurrence of a first-order density and entropy-driven liquid-liquid phase transition (LLPT) in the supercooled liquid state. The observations have become controversial because of the presence of crystalline material that can be formed simultaneously and that can mask the nucleation and growth of the lower density liquid. The previous work is summarized here along with arguments for and against the different viewpoints. Also two studies have been undertaken to investigate the LLPT in this refractory system with emphasis on determining the structure of unequivocally amorphous materials. These include the in situ high energy X-ray diffraction (HEXRD) of supercooled Y2O3 - Al2O3 liquids and the low frequency vibrational dynamics of recovered glasses. Manybody molecular dynamics simulations are also used to interpret the results of both studies. The HEXRD measurements, combined with aerodynamic levitation and rapid data acquisition techniques, show that for the 20 mol% Y2O3 (i.e. AlY20) liquid there is a shift in the position of the first peak in the diffraction pattern over a narrow temperature range (2100-1800 K) prior to crystallization. Microbeam Raman spectroscopy measurements made on AlY20 glasses clearly show contrasting spectra in the low frequency part of the spectrum for low(LDA) and high-density (HDA) glassy regions. The molecular dynamics simulations identify contrasting coordination environments around oxygen anions for the high- (HDL) and low-density (LDL) liquids. (C) 2014 Elsevier B.V. All rights reserved.

  17. Managing liquidity

    DEFF Research Database (Denmark)

    Pokutta, Sebastian; Schmaltz, Christian


    Large banking groups face the question of how to optimally allocate and generate liquidity: in a central liquidity hub or in many decentralized branches. We translate this question into a facility location problem under uncertainty. We show that volatility is the key driver behind (de-)centraliza......Large banking groups face the question of how to optimally allocate and generate liquidity: in a central liquidity hub or in many decentralized branches. We translate this question into a facility location problem under uncertainty. We show that volatility is the key driver behind (de......-)centralization. We provide an analytical solution for the 2-branch model and show that a liquidity center can be interpreted as an option on immediate liquidity. Therefore, its value can be interpreted as the price of information, i.e., the price of knowing the exact demand. Furthermore, we derive the threshold...... above which it is advantageous to open a liquidity center and show that it is a function of the volatility and the characteristic of the bank network. Finally, we discuss the n-branch model for real-world banking groups (10-60 branches) and show that it can be solved with high granularity (100 scenarios...

  18. Nanoscale crystallinity modulates cell proliferation on plasma sprayed surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Alan M. [School of Applied Sciences, University of Huddersfield, Huddersfield HD1 3DH (United Kingdom); Paxton, Jennifer Z.; Hung, Yi-Pei; Hadley, Martin J.; Bowen, James; Williams, Richard L. [School of Chemical Engineering, University of Birmingham, Edgbaston, B15 2TT (United Kingdom); Grover, Liam M., E-mail: [School of Chemical Engineering, University of Birmingham, Edgbaston, B15 2TT (United Kingdom)


    Calcium phosphate coatings have been applied to the surface of metallic prostheses to mediate hard and soft tissue attachment for more than 40 years. Most coatings are formed of high purity hydroxyapatite, and coating methods are often designed to produce highly crystalline surfaces. It is likely however, that coatings of lower crystallinity can facilitate more rapid tissue attachment since the surface will exhibit a higher specific surface area and will be considerably more reactive than a comparable highly crystalline surface. Here we test this hypothesis by growing a population of MC3T3 osteoblast-like cells on the surface of two types of hip prosthesis with similar composition, but with differing crystallinity. The surfaces with lower crystallinity facilitated more rapid cell attachment and increased proliferation rate, despite having a less heterogeneous surface topography. This work highlights that the influence of the crystallinity of HA at the nano-scale is dominant over macro-scale topography for cell adhesion and growth. Furthermore, crystallinity could be easily adjusted by without compromising coating purity. These findings could facilitate designing novel coated calcium phosphate surfaces that more rapidly bond tissue following implantation. - Highlights: • Crystallinity of HA at the nano-scale was dominant over macro-scale topography. • Lower crystallinity caused rapid cell attachment and proliferation rate. • Crystallinity could be easily adjusted by without compromising coating purity.

  19. Particle tracking microrheology of lyotropic liquid crystals. (United States)

    Alam, Mohammad Mydul; Mezzenga, Raffaele


    We present comprehensive results on the microrheological study of lyotropic liquid crystalline phases of various space groups constituted by water-monoglyceride (Dimodan) mixtures. In order to explore the viscoelastic properties of these systems, we use particle tracking of probe colloidal particles suitably dispersed in the liquid crystals and monitored by diffusing wave spectroscopy. The identification of the various liquid crystalline phases was separately carried out by small-angle X-ray scattering. The restricted motion of the particles was monitored and identified by the decay time of intensity autocorrelation function and the corresponding time-dependent mean square displacement (MSD), which revealed space group-dependent behavior. The characteristic time extracted by the intersection of the slopes of the MSD at short and long time scales, provided a characteristic time which could be directly compared with the relaxation time obtained by microrheology. Further direct comparison of microrheology and bulk rheology measurements was gained via the Laplace transform of the generalized time-dependent MSD, yielding the microrheology storage and loss moduli, G'(ω) and G''(ω), in the frequency domain ω. The general picture emerging from the microrheology data is that all liquid crystals exhibit viscoelastic properties in line with results from bulk rheology and the transition regime (elastic to viscous) differs according to the specific liquid crystal considered. In the case of the lamellar phase, a plastic fluid is measured by bulk rheology, while microrheology indicates viscoelastic behavior. Although we generally find good qualitative agreement between the two techniques, all liquid crystalline systems are found to relax faster when studied with microrheology. The most plausible explanation for this difference is due to the different length scales probed by the two techniques: that is, microscopical relaxation on these structured fluids, is likely to occur at

  20. Experimental and theoretical evidence for bilayer-by-bilayer surface melting of crystalline ice

    DEFF Research Database (Denmark)

    Sánchez, M. Alejandra; Kling, Tanja; Ishiyama, Tatsuya


    On the surface of water ice, a quasi-liquid layer (QLL) has been extensively reported at temperatures below its bulk melting point at 273 K. Approaching the bulk melting temperature from below, the thickness of the QLL is known to increase. To elucidate the precise temperature variation of the QLL......, and its nature, we investigate the surface melting of hexagonal ice by combining noncontact, surfacespecific vibrational sum frequency generation (SFG) spectroscopy and spectra calculated from molecular dynamics simulations. Using SFG, we probe the outermost water layers of distinct single crystalline ice...

  1. Performance comparison between crystalline and co-amorphous salts of indomethacin-lysine

    DEFF Research Database (Denmark)

    Kasten, Georgia; Nouri, Khatera; Grohganz, Holger


    The introduction of a highly water soluble amino acid as co-amorphous co-former has previously been shown to significantly improve the dissolution rate of poorly water soluble drugs. In this work, dry ball milling (DBM) and liquid assisted grinding (LAG) were used to prepare different physical....... Intrinsic dissolution and powder dissolution studies demonstrated an increased dissolution rate of the drug in the co-amorphous salt compared to pure amorphous IND and also the crystalline drug-LYS salt. Furthermore, the co-amorphous IND-LYS salt presented long term physical stability in dry conditions...

  2. Self-assembled crystalline silicon carbide Y junctions by coalescence of nucleated iron catalysts (United States)

    Liu, Zhenyu; Srot, V.; Yang, Judith C.


    Self-assembled crystalline SiC Y junctions with either parallel or inclined branches have been created via the iron catalyzed vapor-liquid-solid mechanism. These formations are attributed to coalescence of two catalyst droplets that have already each formed a SiC nanowire branch, where the merged catalyst remains catalytically active and catalyzes the stem growth of the Y junction. The SiC Y junction formed by two parallel branches follows the original growth direction and creates a single crystal stem. While the SiC Y junction formed by two inclined branches, the merged catalyst creates a bicrystal stem with a planar grain boundary along the center.

  3. Single crystalline nanostructures of topological crystalline insulator SnTe with distinct facets and morphologies. (United States)

    Li, Z; Shao, S; Li, N; McCall, K; Wang, J; Zhang, S X


    Topological crystalline insulators (TCIs) are a new class of topological materials that possess unique metallic surface states protected by crystalline mirror symmetry. Their topological surface properties are expected to strongly depend on the surface orientation. By combining density functional theory (DFT) calculations and synthesis experiments, we demonstrate the controlled growth of single crystalline nanostructures of the prototypical TCI SnTe with distinct facets and morphologies. Our calculations suggest that the excess energy of the {111} surfaces can be either higher or lower than that of the {100} surfaces, depending on the stoichiometry, while the {110} is always higher than the {100}. In our synthesis experiment, we qualitatively controlled the stoichiometry by tailoring the growth temperature and obtained two types of single crystalline nanowires: smooth nanowires dominated by {100} facets at high temperatures and zigzag nanowires composed of both {100} and {111} surfaces at low temperatures. Notably, there is no {110} facet in our nanostructures, strongly supporting the DFT calculations. Our device fabrication and electrical characterizations suggest that both types of nanowires are suitable for transport studies of topological surface states.

  4. Hydrodynamic pressure in liquid filled container (United States)

    Maiti, Pabitra Ranjan


    Liquid storage tanks are used to store oil, drinking water and different liquids which are necessary in industry and energy production. Partially liquid filled container shows free surface movement under external excitation this phenomenon is known as sloshing of liquid. When external excitation frequency matches the natural frequency of sloshing, a violent oscillation may occur that causes excess dynamic pressure on the tank structure. The dynamic behavior of liquid storage tanks under seismic excitation has been the subject of numerous theoretical and experimental investigations. This paper presents a pressure based finite element analysis of the liquid-structure systems considering the coupled effect of elastic structure and liquid. The equation of motion of the liquid is considered as incompressible and inviscid. The hydrodynamic pressure variation along a wall of prismatic container is studied and presented for different fill depth of liquid under sinusoidal base excitation.

  5. The surface quasiliquid melt acceleration and the role of thermodynamic phase in the thermal decomposition of crystalline organic explosives

    Energy Technology Data Exchange (ETDEWEB)

    Henson, Bryan F [Los Alamos National Laboratory


    We show that melt acceleration in the thermal decomposition of crystalline organic solids is a manifestation of the surface quasiliquid phase. We derive a single universal rate law for melt acceleration that is a simple function of the metastable liquid activity below the melting point, and has a zero order term proportional to the quasiliquid thickness. We argue that the underlying mechanisms of this model will provide a molecular definition for the stability of the class of secondary explosives.

  6. The induction of lipid peroxidation during the acute oxidative stress response induced by intratracheal instillation of fine crystalline silica particles in rats. (United States)

    Fukui, Hiroko; Endoh, Shigehisa; Shichiri, Mototada; Ishida, Noriko; Hagihara, Yoshihisa; Yoshida, Yasukazu; Iwahashi, Hitoshi; Horie, Masanori


    Crystalline silica (SiO2) is an important material for industry but is considered potentially carcinogenic. Inhalation of a crystalline SiO2 aerosol may contribute to serious lung diseases. Crystalline SiO2 particles are commonly used as a positive control in toxicity assays of particulate materials (e.g. nanoparticles). Crystalline SiO2 induces oxidative stress resulting in lipid peroxidation, but the acute oxidative stress response in the lung is not well understood. Lipid peroxidation during the acute stage of oxidative stress after instillation of crystalline SiO2 into rats was examined by bronchoalveolar lavage fluid (BALF) analysis. The levels of 8-iso-prostaglandin F2α and hydroxyoctadecadienoic acid (HODE) in the BALF were measured using liquid chromatography coupled to quadrupole mass spectrometry. The concentration of the antioxidant protein heme oxygenase-1 (HO-1) in the BALF was determined using enzyme-linked immunosorbent assay. Intratracheal instillation of crystalline SiO2 increased the level of HODE and HO-1 in BALF at 24 h after administration. The levels of HODE and HO-1 returned to baseline at 72 h after instillation. Lactate dehydrogenase leakage was observed only after 1 h instillation. These results suggest that the contribution of oxidative stress to the pulmonary toxicity of crystalline SiO2 is minimal in the early acute stage after exposure. © The Author(s) 2014.

  7. Liquidlike nature of crystalline n-butane and n-pentane films studied by time-of-flight secondary ion mass spectrometry. (United States)

    Souda, Ryutaro


    Crystallization of vapor-deposited thin films of n-butane and n-pentane has been investigated using temperature-programmed time-of-flight secondary ion mass spectrometry. The morphology of thin n-butane (n-pentane) films changes at around the calorimetric crystallization temperature of 65 K (85 K) as a result of crystallization of the supercooled liquid. The morphology of the crystal grains of n-butane changes at 85 K; the butane molecules permeate through porous amorphous-solid-water films above this temperature. The crystal grains of n-pentane are smaller in size than those of n-butane, forming a smoother crystalline film. However, the crystalline n-pentane film dewets abruptly at higher temperatures, depending on the film thickness. The liquidlike nature of crystalline n-pentane (n-butane) is attributable to premelting (coexisting second liquid).

  8. Liquid Phase Epitaxial Growth of Al-doped f-SiC for White Light-Emitting Diodes

    DEFF Research Database (Denmark)

    Tang, Kai; Ma, Xiang; can der Eijk, Casper

    efficiency, better light quality and longer lifespan, compared to the current yellow phosphor based white LEDs.Liquid phase epitaxy technology can yield a high crystalline quality in terms of structural perfection owing to the fact that it is a near equilibrium crystalline growth process. In addition...

  9. Nanomechanical morphology of amorphous, transition, and crystalline domains in phase change memory thin films (United States)

    Bosse, J. L.; Grishin, I.; Huey, B. D.; Kolosov, O. V.


    In the search for phase change materials (PCM) that may rival traditional random access memory, a complete understanding of the amorphous to crystalline phase transition is required. For the well-known Ge2Sb2Te5 (GST) and GeTe (GT) chalcogenides, which display nucleation and growth dominated crystallization kinetics, respectively, this work explores the nanomechanical morphology of amorphous and crystalline phases in 50 nm thin films. Subjecting these PCM specimens to a lateral thermal gradient spanning the crystallization temperature allows for a detailed morphological investigation. Surface and depth-dependent analyses of the resulting amorphous, transition and crystalline regions are achieved with shallow angle cross-sections, uniquely implemented with beam exit Ar ion polishing. To resolve the distinct phases, ultrasonic force microscopy (UFM) with simultaneous topography is implemented revealing a relative stiffness contrast between the amorphous and crystalline phases of 14% for the free film surface and 20% for the cross-sectioned surface. Nucleation is observed to occur preferentially at the PCM-substrate and free film interface for both GST and GT, while fine subsurface structures are found to be sputtering direction dependent. Combining surface and cross-section nanomechanical mapping in this manner allows 3D analysis of microstructure and defects with nanoscale lateral and depth resolution, applicable to a wide range of materials characterization studies where the detection of subtle variations in elastic modulus or stiffness are required.

  10. Dispersion relations of the acoustic modes in divalent liquid metals

    Directory of Open Access Journals (Sweden)

    Inui Masanori


    Full Text Available Collective dynamics in liquid Ca and liquid Cd was studied by inelastic x-ray scattering (IXS. Using our experimental technique to prepare proper sample cells and high performance of an IXS beamline (BL35XU at SPring-8 in Japan, the dynamic structure factor with reasonable statistics was obtained for these divalent liquid metals. For both liquids, the dynamic structure factor at low Q exhibits a central peak with a shoulder or small hump clearly visible on each side, and the inelastic excitation energy determined using the model function composed of Lorentzian and the damped harmonic oscillator function disperses with increasing Q. The dispersion curves of these liquids were compared with that of the longitudinal acoustic phonon in each crystalline phase. From these results, clear difference in the interatomic interaction be- tween liquid Ca and liquid Cd was inferred.

  11. Polyethylene nano crystalsomes formed at a curved liquid/liquid interface. (United States)

    Wang, Wenda; Staub, Mark C; Zhou, Tian; Smith, Derrick M; Qi, Hao; Laird, Eric D; Cheng, Shan; Li, Christopher Y


    Crystallization is incommensurate with nanoscale curved space due to the lack of three dimensional translational symmetry of the latter. Herein, we report the formation of single-crystal-like, nanosized polyethylene (PE) capsules using a miniemulsion solution crystallization method. The miniemulsion was formed at elevated temperatures using PE organic solution as the oil phase and sodium dodecyl sulfate as the surfactant. Subsequently, cooling the system stepwisely for controlled crystallization led to the formation of hollow, nanosized PE crystalline capsules, which are named as crystalsomes since they mimic the classical self-assembled structures such as liposome, polymersome and colloidosome. We show that the formation of the nanosized PE crystalsomes is driven by controlled crystallization at the curved liquid/liquid interface of the miniemulson droplet. The morphology, structure and mechanical properties of the PE crystalsomes were characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and atomic force spectroscopy. Electron diffraction showed the single-crystal-like nature of the crystalsomes. The incommensurateness between the nanocurved interface and the crystalline packing led to reduced crystallinity and crystallite size of the PE crystalsome, as observed from the X-ray diffraction measurements. Moreover, directly quenching the emulsion below the spinodal line led to the formation of hierarchical porous PE crystalsomes due to the coupling of the PE crystallization and liquid/liquid phase separation. We anticipate that this unique crystalsome represents a new type of nanostructure that might be used as nanodrug carriers and ultrasound contrast agents.

  12. Gibbs free-energy difference between the glass and crystalline phases of a Ni-Zr alloy (United States)

    Ohsaka, K.; Trinh, E. H.; Holzer, J. C.; Johnson, W. L.


    The heats of eutectic melting and devitrification, and the specific heats of the crystalline, glass, and liquid phases have been measured for a Ni24Zr76 alloy. The data are used to calculate the Gibbs free-energy difference, Delta G(AC), between the real glass and the crystal on an assumption that the liquid-glass transition is second order. The result shows that Delta G(AC) continuously increases as the temperature decreases in contrast to the ideal glass case where Delta G(AC) is assumed to be independent of temperature.

  13. Liquid explosives

    CERN Document Server

    Liu, Jiping


    The book drawing on the author's nearly half a century of energetic materials research experience intends to systematically review the global researches on liquid explosives. The book focuses on the study of the conception, explosion mechanism, properties and preparation of liquid explosives. It provides a combination of theoretical knowledge and practical examples in a reader-friendly style. The book is likely to be interest of university researchers and graduate students in the fields of energetic materials, blasting engineering and mining.

  14. Growth undercooling in multi-crystalline pure silicon and in silicon containing light impurities (C and O) (United States)

    Riberi-Béridot, T.; Tsoutsouva, M. G.; Regula, G.; Reinhart, G.; Périchaud, I.; Baruchel, J.; Mangelinck-Noël, N.


    Undercooling during the solidification of silicon is an essential parameter that plays a major role in grain nucleation and growth. In this study, the undercooling of the solid-liquid interface during growth of multi-crystalline silicon samples is measured for two types of silicon: pure, and containing light elements (carbon and oxygen) to assess and compare their impact on crystal growth. The solid-liquid interface undercooling is measured using in situ and real time X-ray synchrotron imaging during solidification. As a subsequent step, ex situ Electron Backscattered Diffraction (EBSD) is performed to obtain information about the crystalline structure, the grain orientation and the grain boundary character. Two main conclusions arise: (i) the undercooling of the global solid-liquid front increases linearly with the growth rate which indicates uniform attachment, i.e. all atoms are equivalent, (ii) the same trend is observed for pure silicon and silicon containing carbon and oxygen. Indeed, the growth law obtained is comparable in both cases, which suggests that the solutal effect is negligible as concern the undercooling in the case of a contamination with carbon (C) and oxygen (O). However, there is a clear effect of the impurity presence on the crystalline structure and grain boundary type distribution. Many grains nucleate during growth in samples containing C and O, which suggests the presence of precipitates on which grain nucleation is favored.

  15. Characterization of crystalline structures in Opuntia ficus-indica


    Contreras-Padilla, Margarita; Eric M. Rivera-Muñoz; Gutiérrez-Cortez, Elsa; del López, Alicia Real; Rodríguez-García, Mario Enrique


    This research studies the crystalline compounds present in nopal (Opuntia ficus-indica) cladodes. The identification of the crystalline structures was performed using X-ray diffraction, scanning electron microscopy, mass spectrometry, and Fourier transform infrared spectroscopy. The crystalline structures identified were calcium carbonate (calcite) [CaCO3], calcium-magnesium bicarbonate [CaMg(CO3)2], magnesium oxide [MgO], calcium oxalate monohydrate [Ca(C2O4)•(H2O)], potassium peroxydiphosph...

  16. Crystalline-Silicon Solar Cells for the 21st Century

    Energy Technology Data Exchange (ETDEWEB)

    Tsuo, Y. S.; Wang, T. H.; Ciszek, T. F.


    The worldwide market share for crystalline-silicon solar cells has increased steadily in the last 10 years. In 1998, about 87% of the photovoltaic modules shipped worldwide are based on crystalline silicon. This dominance will likely continue into at least the first few years of the 21st century. The long-term growth of crystalline-silicon solar cells will depend on the development of low-cost polysilicon feedstock, silicon films, and advanced cell and module manufacturing processes.

  17. High-flux solar furnace processing of crystalline silicon solar cells (United States)

    Tsuo, Y. S.; Pitts, J. R.; Menna, P.; Landry, M. D.; Gee, J. M.; Ciszek, T. F.


    We studied the processing of crystalline-silicon solar cells using a 10-kW, high-flux solar furnace (HFSF). Major findings of this study include: (1) hydrogenated amorphous silicon films deposited on glass substrates can be converted to microcrystalline silicon by solid-phase crystallization in 5 seconds or less in the HFSF; (2) the presence of concentrated sunlight enhances the diffusion of phosphorus into silicon from a spin-on dopant source; (3) the combination of a porous-silicon surface layer and photo-enhanced impurity diffusion is very effective in gettering impurities from a metallurgical-grade silicon wafer or thin-layer silicon deposited using liquid-phase epitaxy; (4) a 14.1%-efficient crystalline-silicon solar cell with an area of 4.6 cm2 was fabricated using the HFSF for simultaneous diffusion of front n+-p and back p-p+ junctions; and (5) we have shown that the HFSF can be used to texture crystalline-silicon surfaces and to anneal metal contacts printed on a silicon solar cell.

  18. Quality by Design approach to spray drying processing of crystalline nanosuspensions. (United States)

    Kumar, Sumit; Gokhale, Rajeev; Burgess, Diane J


    Quality by Design (QbD) principles were explored to understand spray drying process for the conversion of liquid nanosuspensions into solid nano-crystalline dry powders using indomethacin as a model drug. The effects of critical process variables: inlet temperature, flow and aspiration rates on critical quality attributes (CQAs): particle size, moisture content, percent yield and crystallinity were investigated employing a full factorial design. A central cubic design was employed to generate the response surface for particle size and percent yield. Multiple linear regression analysis and ANOVA were employed to identify and estimate the effect of critical parameters, establish their relationship with CQAs, create design space and model the spray drying process. Inlet temperature was identified as the only significant factor (p value drug surface melting and hence aggregation of the dried nano-crystalline powders. Aspiration and flow rates were identified as significant factors affecting yield (p value dried at higher inlet temperatures had lower moisture compared to those dried at lower inlet temperatures. Published by Elsevier B.V.

  19. Lyotropic Liquid Crystal Phases from Anisotropic Nanomaterials

    Directory of Open Access Journals (Sweden)

    Ingo Dierking


    Full Text Available Liquid crystals are an integral part of a mature display technology, also establishing themselves in other applications, such as spatial light modulators, telecommunication technology, photonics, or sensors, just to name a few of the non-display applications. In recent years, there has been an increasing trend to add various nanomaterials to liquid crystals, which is motivated by several aspects of materials development. (i addition of nanomaterials can change and thus tune the properties of the liquid crystal; (ii novel functionalities can be added to the liquid crystal; and (iii the self-organization of the liquid crystalline state can be exploited to template ordered structures or to transfer order onto dispersed nanomaterials. Much of the research effort has been concentrated on thermotropic systems, which change order as a function of temperature. Here we review the other side of the medal, the formation and properties of ordered, anisotropic fluid phases, liquid crystals, by addition of shape-anisotropic nanomaterials to isotropic liquids. Several classes of materials will be discussed, inorganic and mineral liquid crystals, viruses, nanotubes and nanorods, as well as graphene oxide.

  20. Energy transport in crystalline DNA composites

    Directory of Open Access Journals (Sweden)

    Zaoli Xu


    Full Text Available This work reports on the synthesis of crystalline DNA-composited films and microfibers, and details the study of thermal energy transport in them. The transient electro-thermal technique is used to characterize the thermal transport in DNA composite microfibers, and the photothermal technique is used to explore the thermal transport in the thickness direction of DNA films. Compared with microfibers, the DNA films are found to have a higher thermal transport capacity, largely due to the carefully controlled crystallization process in film synthesis. In high NaCl concentration solutions, the bond of the Na+ ion and phosphate group aligns the DNA molecules with the NaCl crystal structure during crystallization. This results in significant enhancement of thermal transport in the DNA films with aligned structure.

  1. Quasi-crystalline geometry for architectural structures

    DEFF Research Database (Denmark)

    Weizierl, Barbara; Wester, Ture


    . The purpose of the paper is to investigate some possibilities for the application of Quasi-Crystal geometry for structures in architecture. The basis for the investigations is A: to use the Golden Cubes (the two different hexahedra consisting of rhombic facets where the length of the diagonals has the Golden......Artikel på CD-Rom 8 sider. The quasi-crystal (QC) type of material was discovered in 1983 by Dan Schechtman from Technion, Haifa. This new crystalline structure of material broke totally with the traditional conception of crystals and geometry introducing non-periodic close packing of cells...... ratio) as basic elements for aperiodic 3D geometries and B: to raise aperiodic Penrose tilings and its binary substitutions from their 2D basis into 3D QC geometries and describe the structural behaviour for these spatial configurations....

  2. Crystalline lens radioprotectors; Les radioprotecteurs du cristallin

    Energy Technology Data Exchange (ETDEWEB)

    Belkacemi, Y.; Pasquier, D.; Castelain, B.; Lartigau, E. [Centre de Lutte Contre le Cancer Oscar-Lambret, Dept. de Radiotherapie, 59 - Lille (France); Warnet, J.M. [Paris-5 Univ., Lab. de Toxicologie, UFR Pharmacie, Unite de Pharmacotoxicologie Cellulaire, service Pharmacie, Centre Hospitalier National d' Ophtalmologie des 15-20, 75 (France)


    During more than a half of century, numerous compounds have been tested in different models against radiation-induced cataract. In this report, we will review the radioprotectors that have been already tested for non-human crystalline lens protection. We will focus on the most important published studies in this topic and the mechanisms of cyto-protection reported in. vitro and in. vivo from animals. The most frequent mechanisms incriminated in the cyto-protective effect are: free radical scavenging, limitation of lipid peroxidation, modulation of cycle progression increase of intracellular reduced glutathione pool, reduction of DNA strand breaks and limitation of apoptotic cell death. Arnifostine (or Ethyol) and anethole dithiolethione (or Sulfarlem), already used clinically as chemo- and radio-protectants, could be further test?r for ocular radioprotection particularly for radiation-induced cataract. (author)

  3. Entropy based fingerprint for local crystalline order (United States)

    Piaggi, Pablo M.; Parrinello, Michele


    We introduce a new fingerprint that allows distinguishing between liquid-like and solid-like atomic environments. This fingerprint is based on an approximate expression for the entropy projected on individual atoms. When combined with local enthalpy, this fingerprint acquires an even finer resolution and it is capable of discriminating between different crystal structures.

  4. Nano-biphasic ionic liquid systems composed of hydrophobic phosphonium salts and a hydrophilic ammonium salt. (United States)

    Taguchi, Satomi; Ichikawa, Takahiro; Kato, Takashi; Ohno, Hiroyuki


    A combination of a phosphonium-type-zwitterions-lithium bis(trifluoromethanesulfonyl)imide complex and a hydrophilic ammonium salt provides a nanosegregated liquid-crystalline matrix consisting of hydrophilic ionic liquid (IL) domains and hydrophobic IL domains. This journal is © The Royal Society of Chemistry 2012

  5. Thermal Analysis, Mechanical and Rheological Behaviour of Melt Manufactured Polyethylene/Liquid Crystal Polymer Blends

    Directory of Open Access Journals (Sweden)



    Full Text Available Modification of properties of conventional thermoplastics with thermotropic liquid crystal polymers, from one hand, allows decrease their viscosities, substantially facilitating processing conditions, and, from another hand, allows increase their exploitation properties. Orientation of the labile structure of liquid crystal polymer in extrusion or injection moulding causes specific reinforcement (so-called self-reinforcement to occur in the blends containing liquid crystal polymer. Up to now the effect of self-reinforcement is mostly investigated in the blends, containing considerable amount of liquid crystal polymer. In this research the effect of minor amounts of liquid crystalline co-polyester modifier on the properties of polyethylene is investigated. Various compositions of laboratory synthesized hydroxybenzoic acid /polyethylene terephtalate copolymer containing polyethylene composites have been manufactured by thermoplastic blending. It has been observed that 1 modulus of elasticity, yield strength and ultimate strength increase with raising the content of liquid crystalline modifier; 2 void content in the investigated polyethylene/liquid crystal copolymer composites is not greater that 1 %; 3 addition of liquid crystalline co-polyester modifier improves arrangement of PE crystalline phase.

  6. Conformational fluctuations affect protein alignment in dilute liquid crystal media

    NARCIS (Netherlands)

    Louhivuori, M; Otten, R; Lindorff-Larsen, K; Annila, A


    The discovery of dilute liquid crystalline media to align biological macromolecules has opened many new possibilities to study protein and nucleic acid structures by NMR spectroscopy. We inspect the basic alignment phenomenon for an ensemble of protein conformations to deduce relative contributions

  7. Conformational fluctuations affect protein alignment in dilute liquid crystal media

    DEFF Research Database (Denmark)

    Louhivuori, M.; Otten, R.; Lindorff-Larsen, Kresten


    The discovery of dilute liquid crystalline media to align biological macromolecules has opened many new possibilities to study protein and nucleic acid structures by NMR spectroscopy. We inspect the basic alignment phenomenon for an ensemble of protein conformations to deduce relative contributions...

  8. Liquid Crystals (United States)


    Thermochromic liquid crystals, or TLCs, are a type of liquid crystals that react to changes in temperature by changing color. The Hallcrest/NASA collaboration involved development of a new way to visualize boundary layer transition in flight and in wind tunnel testing of aircraft wing and body surfaces. TLCs offered a new and potentially better method of visualizing the boundary layer transition in flight. Hallcrest provided a liquid crystal formulation technique that afforded great control over the sensitivity of the liquid crystals to varying conditions. Method is of great use to industry, government and universities for aerodynamic and hydrodynamic testing. Company's principal line is temperature indicating devices for industrial use, such as non-destructive testing and flaw detection in electric/electronic systems, medical application, such as diagnostic systems, for retail sale, such as room, refrigerator, baby bath and aquarium thermometers, and for advertising and promotion specials. Additionally, Hallcrest manufactures TLC mixtures for cosmetic applications, and liquid crystal battery tester for Duracell batteries.

  9. 3-Hydroxykynurenine oxidizes alpha-crystallin: potential role in cataractogenesis. (United States)

    Korlimbinis, Anastasia; Hains, Peter G; Truscott, Roger J W; Aquilina, J Andrew


    The alpha-, beta-, and gamma-crystallins are the major structural proteins of mammalian lenses. The human lens also contains tryptophan-derived UV filters, which are known to spontaneously deaminate at physiological pH and covalently attach to lens proteins. 3-Hydroxykynurenine (3OHKyn) is the third most abundant of the kynurenine UV filters in the lens, and previous studies have shown this compound to be unstable and to be oxidized under physiological conditions, producing H2O2. In this study, we show that methionine and tryptophan amino acid residues are oxidized when bovine alpha-crystallin is incubated with 3-hydroxykynurenine. We observed almost complete oxidation of methionines 1 and 138 in alphaA-crystallin and a similar extent of oxidation of methionines 1 and 68 in alphaB-crystallin after 48 h. Tryptophans 9 and 60 in alphaB-crystallin were oxidized to a lesser extent. AlphaA-crystallin was also found to have 3OHKyn bound to its single cysteine residue. Examination of normal aged human lenses revealed no evidence of oxidation of alpha-crystallin; however, oxidation was detected at methionine 1 in both alphaA- and alphaB-crystallin from human cataractous lenses. Age-related nuclear cataract is associated with coloration and insolubilization of lens proteins and extensive oxidation of cysteine and methionine residues. Our findings demonstrate that 3-hydroxykynurenine can readily catalyze the oxidation of methionine residues in both alphaB- and alphaA-crystallin, and it has been reported that alpha-crystallin modified in this way is a poorer chaperone. Thus, 3-hydroxykynurenine promotes the oxidation and modification of crystallins and may contribute to oxidative stress in the human lens.

  10. Transformations of Liquid Metals in Ionic Liquid


    Liu, Fujun; Yu, Yongze; Liu, Jing


    Experimental studies were carried out on the motions and transformations of liquid metal in ionic liquid under applied electric field. The induced vortex rings and flows of ionic liquid were determined via the photographs taken sequentially over the experiments. The polarization of electric double layer of liquid metals was employed to explain the flow of ionic liquid with the presence of liquid metal. Unlike former observation of liquid metal machine in conventional solution, no gas bubble w...

  11. Polymer Crystals Formed at Liquid-Liquid Interface Show Broken Symmetry (United States)

    Wang, Wenda; Qi, Hao; Huang, Ziyin; Li, Christopher Y.; Soft Matter Research Group Team


    Curved space is incommensurate with typical ordered structures with three-dimensional translational symmetry. However, upon assembly, soft matter, including colloids, amphiphiles, and block copolymers, often form structures depicting curved surface/interface. On the other hand, twisted and curved crystals are often observed in crystalline polymers. Various mechanisms have been proposed for these non-flat crystalline morphologies. In this presentation, we will discuss the recent development of crystallization at flat and curved liquid/liquid (L/L) interface. We show that structure, morphology and chain folding behaviors are strongly affected by L/L interfacial energy and polymer chain ends. Both polyethylene and poly-L-lactic acid single crystal shells have been obtained using curved L/L interface. Polymer crystallization behavior at L/L interface will be compared with solution and bulk crystallization.

  12. Quantitative aspects of crystalline lactose in milk products

    NARCIS (Netherlands)

    Roetman, K.


    The occurrence of crystalline lactose in milk products and its influence on their physical properties are briefly reviewed. The importance of the quantitive determination of crystalline lactose for scientific and industrial purposes is indicated, and a summary is given of our earlier work. This

  13. Single Molecule Study of Cellulase Hydrolysis of Crystalline Cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Y.-S.; Luo, Y.; Baker, J. O.; Zeng, Y.; Himmel, M. E.; Smith, S.; Ding, S.-Y.


    This report seeks to elucidate the role of cellobiohydrolase-I (CBH I) in the hydrolysis of crystalline cellulose. A single-molecule approach uses various imaging techniques to investigate the surface structure of crystalline cellulose and changes made in the structure by CBH I.

  14. Аnodic formation of nanoporous crystalline niobium oxide

    Directory of Open Access Journals (Sweden)



    Full Text Available The research results of anodic deposition of crystalline niobium oxide are presented in this work. The factors that have an impact on crystalline phase nucleation and its primary growth are revealed. Dependence of morphology and properties of nanoporous niobium oxide on modes of its formation is shown.

  15. Determination of cellulose I crystallinity by FT-Raman spectroscopy (United States)

    Umesh P. Agarwal; Richard S. Reiner; Sally A. Ralph


    Two new methods based on FT-Raman spectroscopy, one simple, based on band intensity ratio, and the other, using a partial least-squares (PLS) regression model, are proposed to determine cellulose I crystallinity. In the simple method, crystallinity in semicrystalline cellulose I samples was determined based on univariate regression that was first developed using the...

  16. α-Crystallins Are Small Heat Shock Proteins: Functional and Structural Properties. (United States)

    Tikhomirova, T S; Selivanova, O M; Galzitskaya, O V


    During its life cycle, a cell can be subjected to various external negative effects. Many proteins provide cell protection, including small heat shock proteins (sHsp) that have chaperone-like activity. These proteins have several important functions involving prevention of apoptosis and retention of cytoskeletal integrity; also, sHsp take part in the recovery of enzyme activity. The action mechanism of sHsp is based on the binding of hydrophobic regions exposed to the surface of a molten globule. α-Crystallins presented in chordate cells as two αA- and αB-isoforms are the most studied small heat shock proteins. In this review, we describe the main functions of α-crystallins, features of their secondary and tertiary structures, and examples of their partners in protein-protein interactions.

  17. Crystallinity of the epitaxial heterojunction of C60 on single crystal pentacene (United States)

    Tsuruta, Ryohei; Mizuno, Yuta; Hosokai, Takuya; Koganezawa, Tomoyuki; Ishii, Hisao; Nakayama, Yasuo


    The structure of pn heterojunctions is an important subject in the field of organic semiconductor devices. In this work, the crystallinity of an epitaxial pn heterojunction of C60 on single crystal pentacene is investigated by non-contact mode atomic force microscopy and high-resolution grazing incidence x-ray diffraction. Analysis shows that the C60 molecules assemble into grains consisting of single crystallites on the pentacene single crystal surface. The in-plane mean crystallite size exceeds 0.1 μm, which is at least five time larger than the size of crystallites deposited onto polycrystalline pentacene thin films grown on SiO2. The results indicate that improvement in the crystal quality of the underlying molecular substrate leads to drastic promotion of the crystallinity at the organic semiconductor heterojunction.

  18. Temporal changes in wood crystalline cellulose during degradation by brown rot fungi

    DEFF Research Database (Denmark)

    Howell, Caitlin; Hastrup, Anne Christine Steenkjær; Goodell, Barry


    The degradation of wood by brown rot fungi has been studied intensely for many years in order to facilitate the preservation of in-service wood. In this work we used X-ray diffraction to examine changes in wood cellulose crystallinity caused by the brown rot fungi Gloeophyllum trabeum, Coniophora...... planes in all degraded samples after roughly 20% weight loss, as well as a decrease in the average observed relative peak width at 2¿ = 22.2°. These results may indicate a disruption of the outer most semi-crystalline cellulose chains comprising the wood microfibril. X-ray diffraction analysis of wood...... subjected to biological attack by fungi may provide insight into degradative processes and wood cellulose structure....

  19. Radiocarbon dating of the human eye lens crystallines reveal proteins without carbon turnover throughout life.

    Directory of Open Access Journals (Sweden)

    Niels Lynnerup

    Full Text Available BACKGROUND: Lens crystallines are special proteins in the eye lens. Because the epithelial basement membrane (lens capsule completely encloses the lens, desquamation of aging cells is impossible, and due to the complete absence of blood vessels or transport of metabolites in this area, there is no subsequent remodelling of these fibers, nor removal of degraded lens fibers. Human tissue ultimately derives its (14C content from the atmospheric carbon dioxide. The (14C content of the lens proteins thus reflects the atmospheric content of (14C when the lens crystallines were formed. Precise radiocarbon dating is made possible by comparing the (14C content of the lens crystallines to the so-called bomb pulse, i.e. a plot of the atmospheric (14C content since the Second World War, when there was a significant increase due to nuclear-bomb testing. Since the change in concentration is significant even on a yearly basis this allows very accurate dating. METHODOLOGY/PRINCIPAL FINDINGS: Our results allow us to conclude that the crystalline formation in the lens nucleus almost entirely takes place around the time of birth, with a very small, and decreasing, continuous formation throughout life. The close relationship may be further expressed as a mathematical model, which takes into account the timing of the crystalline formation. CONCLUSIONS/SIGNIFICANCE: Such a life-long permanence of human tissue has hitherto only been described for dental enamel. In confront to dental enamel it must be held in mind that the eye lens is a soft structure, subjected to almost continuous deformation, due to lens accommodation, yet its most important constituent, the lens crystalline, is never subject to turnover or remodelling once formed. The determination of the (14C content of various tissues may be used to assess turnover rates and degree of substitution (for example for brain cell DNA. Potential targets may be nervous tissues in terms of senile or pre

  20. Instabilities in liquid crystals

    CERN Document Server

    Barclay, G J


    and we examine the differences which occur for differing dielectric anisotropies. Finally, in Chapter 7 we study how a sample of smectic C liquid crystal behaves when it is subjected to a uniform shear flow within the smectic plane. We find travelling wave solutions for the behaviour of the c-director and adapt these solutions to incorporate the effects of an applied field. This thesis contains theoretical work dealing with the effects of magnetic and electric fields on samples of nematic, smectic A and smectic C liquid crystals. Some background material along with the continuum theory is introduced in Chapter 2. In Chapter 3 we consider the effect on the director within an infinite sample of nematic liquid crystal which is subjected to crossed electric and magnetic fields. In particular we examine the stability of the travelling waves which describe the director motion by considering the behaviour of the stable perturbations as time increases. The work of Chapter 4 examines a bounded sample of smectic A liqu...

  1. Milling induces disorder in crystalline griseofulvin and order in its amorphous counterpart

    Energy Technology Data Exchange (ETDEWEB)

    Otte, Andrew; Zhang, Yan; Carvajal, M. Teresa; Pinal, Rodolfo (Purdue)


    This study investigates two apparently similar thermal signatures, shaped as bimodal exotherms, observed when either the crystalline or the amorphous from of the drug are subjected to milling. Crystalline griseofulvin was cryomilled and the (quenched-melt) amorphous form was subjected to either cryomilling or grinding. The thermal and surface properties of the resulting samples were analyzed using differential scanning calorimetry (DSC) and surface energy analysis. After milling, both the crystalline and the amorphous material revealed visually similar bimodal exothermic events when the heating rate was 20 C min{sup -1}. Under different heating rates, the pair of DSC peaks for the bimodal exotherm of each material behaved entirely different from each other. The two peaks of the bimodal event, as well as the glass transition, can be kinetically resolved for the ground amorphous form using standard mode DSC. In contrast, similar analysis was unable to resolve the bimodal exotherm or a glass transition in the case of the cryomilled crystals. Furthermore, cryomilled crystals do not exhibit a glass transition even when analyzed using modulated DSC. Synchrotron sourced X-ray analysis revealed that grinding the amorphous material results in the nucleation and growth of the crystalline form. Milling thus induces disorder in the crystals of griseofulvin but induces order in the amorphous form of the drug. The surface of the two milled systems consistently exhibited different energetics under a wide range of relative humidity conditions. These findings suggest that cryomilling induces both bulk and surface disorder, specifically, a certain level of dislocations on the crystal. In contrast, grinding the amorphous material lowers the activation energy for crystal formation, inducing nuclei formation and growth throughout the amorphous matrix.

  2. Modeling Textural Processes during Self-Assembly of Plant-Based Chiral-Nematic Liquid Crystals

    Directory of Open Access Journals (Sweden)

    Yogesh K. Murugesan


    Full Text Available Biological liquid crystalline polymers are found in cellulosic, chitin, and DNA based natural materials. Chiral nematic liquid crystalline orientational order is observed frozen-in in the solid state in plant cell walls and is known as a liquid crystal analogue characterized by a helicoidal plywood architecture. The emergence of the plywood architecture by directed chiral nematic liquid crystalline self assembly has been postulated as the mechanism that leads to optimal cellulose fibril organization. In natural systems, tissue growth and development takes place in the presence of inclusions and secondary phases leaving behind characteristic defects and textures, which provide a unique testing ground for the validity of the liquid crystal self-assembly postulate. In this work, a mathematical model, based on the Landau-de Gennes theory of liquid crystals, is used to simulate defect textures arising in the domain of self assembly, due to presence of secondary phases representing plant cells, lumens and pit canals. It is shown that the obtained defect patterns observed in some plant cell walls are those expected from a truly liquid crystalline phase. The analysis reveals the nature and magnitude of the viscoelastic material parameters that lead to observed patterns in plant-based helicoids through directed self-assembly. In addition, the results provide new guidance to develop biomimetic plywoods for structural and functional applications.

  3. Machine Learning of ABO3 Crystalline Compounds (United States)

    Gubernatis, J. E.; Balachandran, P. V.; Lookman, T.

    We apply two advanced machine learning methods to a database of experimentally known ABO3 materials to predict the existence of possible new perovskite materials and possible new cubic perovskites. Constructing a list of 625 possible new materials from charge conserving combinations of A and B atoms in known stable ABO3 materials, we predict about 440 new perovskites. These new perovskites are predicted most likely to occur when the A and B atoms are a lanthanide or actinide, when the A atom is a alkali, alkali earth, or late transition metal, and a when the B atom is a p-block atom. These results are in basic agreement with the recent materials discovery by substitution analysis of Hautier et al. who data-mined the entire ICSD data base to develop the probability that in any crystal structure atom X could be substituted for by atom Y. The results of our analysis has several points of disagreement with a recent high throughput DFT study of ABO3 crystalline compounds by Emery et al. who predict few, if any, new perovskites whose A and B atoms are both a lanthanide. They also predict far more new cubic perovskites than we do: We predict few, if any, with a high degree of probability. This work was supported by the LDRD DR program of the Los Alamos National Laboratory.

  4. Excitonically Coupled States in Crystalline Coordination Networks. (United States)

    Haldar, Ritesh; Mazel, Antoine; Joseph, Reetu; Adams, Michael; Howard, Ian A; Richards, Bryce S; Tsotsalas, Manuel; Redel, Engelbert; Diring, Stéphane; Odobel, Fabrice; Wöll, Christof


    When chromophores are brought into close proximity, noncovalent interactions (π-π/CH-π) can lead to the formation of excitonically coupled states, which bestow new photophysical properties upon the aggregates. Because the properties of the new states not only depend on the strength of intermolecular interactions, but also on the relative orientation, supramolecular assemblies, where these parameters can be varied in a deliberate fashion, provide novel possibilities for the control of photophysical properties. This work reports that core-substituted naphthalene diimides (cNDIs) can be incorporated into surface-mounted metal- organic structures/frameworks (SURMOFs) to yield optical properties strikingly different from conventional aggregates of such molecules, for example, formed in solution or by crystallization. Organic linkers are used, based on cNDIs, well-known organic chromophores with numerous applications in different optoelectronic devices, to fabricate MOF thin films on transparent substrates. A thorough characterization of the properties of these highly ordered chromophoric assemblies reveals the presence of non-emissive excited states in the crystalline material. Structural modulations provide further insights into the nature of the coupling that gives rise to an excited-state energy level in the periodic structure. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Nanomechanics of Single Crystalline Tungsten Nanowires

    Directory of Open Access Journals (Sweden)

    Volker Cimalla


    Full Text Available Single crystalline tungsten nanowires were prepared from directionally solidified NiAl-W alloys by a chemical release from the resulting binary phase material. Electron back scatter diffraction (EBSD proves that they are single crystals having identical crystallographic orientation. Mechanical investigations such as bending tests, lateral force measurements, and mechanical resonance measurements were performed on 100–300 nm diameter wires. The wires could be either directly employed using micro tweezers, as a singly clamped nanowire or in a doubly clamped nanobridge. The mechanical tests exhibit a surprisingly high flexibility for such a brittle material resulting from the small dimensions. Force displacement measurements on singly clamped W nanowires by an AFM measurement allowed the determination of a Young's modulus of 332 GPa very close to the bulk value of 355 GPa. Doubly clamped W nanowires were employed as resonant oscillating nanowires in a magnetomotively driven resonator running at 117 kHz. The Young's modulus determined from this setup was found to be higher 450 GPa which is likely to be an artefact resulting from the shift of the resonance frequency by an additional mass loading.

  6. Crystalline nanocellulose/lauric arginate complexes. (United States)

    Chi, Kai; Catchmark, Jeffrey M


    As a novel sustainable nanomaterial, crystalline nanocellulose (CNC) possesses many unique characteristics for emerging applications in coatings, emulsions, paints, pharmaceutical formulations, and other aqueous composite systems where interactions with oppositely charged surfactants are commonly employed. Herein, the binding interactions between sulfated CNC and a novel biologically-derived cationic surfactant lauric arginate (LAE) were comprehensively examined. Ionic strength and solution pH are two crucial factors in determining the adsorption of LAE to the CNC surface. Three different driving forces were identified for CNC-LAE binding interactions. Additionally, it was found that the adsorption of LAE to the CNC surface could notably impact the surface potential, aggregation state, hydrophobicity and thermal stability of the CNC. This work provides insights on the binding interactions between oppositely charged CNC and surfactants, and highlights the significance of optimizing the concentration of surfactant required to ionically decorate CNC for its enhanced dispersion and compatibilization in non-polar polymer matrices. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Crystalline Organic Cavitands As Microcavity Materials (United States)

    Kane, Christopher Michael

    There has been much interest in inefficiently packed molecular materials and their applications in gas storage, separations, catalysis, etc. Such known materials include metal-organic frameworks (MOFs), polymers of intrinsic microporosity (PIMs), container molecule materials, etc. One way to design inefficiently packed materials is to construct them from compounds that are incapable of close-packing, that is rigid scaffolds with enforced cavities that cannot be filled by self-packing. Cavitand molecules, tetrameric macrocycles derived from calix[4]resorcinarene derivatives, are well known for their propensity to form crystalline inclusion compounds with small molecules; for example, of the 169 examples of calix[4]resorcinarene scaffolds found in the Cambridge Structural Database (CSD), no guest-free forms exist. The guest-free forms of various cavitands, synthesized by literature methods, have been obtained as single crystals by sublimation. Gas inclusion compounds of these cavitands have also been isolated and studied by single crystal x-ray diffraction, thermogravimetric analysis, and 1 H NMR. Furthermore, some cavitand derivatives have shown promise as media for industrial separations (Kr vs. Xe, MeCl vs. DME, Propene vs. Propane).

  8. Rollover risk, liquidity, and macro-prudential regulation


    Ahnert, Toni


    I study rollover risk in the wholesale funding market when intermediaries can hold liquidity ex-ante and are subject to fire sales ex-post. I demonstrate that precautionary liquidity restores multiple equilibria in a global rollover game. An intermediate liquidity level supports both the usual run equilibrium and an efficient equilibrium. I provide a uniqueness refinement to characterize the privately optimal liquidity choice. Because of fire sales, liquidity holdings are strategic substitute...

  9. Short range order in elemental liquids of column IV. (United States)

    Mayo, M; Shor, S; Yahel, E; Makov, G


    The short range order (SRO) in liquid elements of column IV is analysed within the quasi-crystalline model across a wide range of temperatures. It is found that l-Si, Ge, and Sn are well described with a beta-tin like SRO. In contrast, Pb retains a bcc-like SRO similar to other simple elemental liquids. However, a distinction is found between the SRO in Si and Ge and that in Sn, where the latter has a more rigid structure. This difference persists across the entire temperature range examined but is overcome in Si at pressures above 8 GPa, where the liquid structure evolves towards that of Sn.

  10. Liquid/liquid heat exchanger (United States)

    Miller, C. G.


    Conceptual design for heat exchanger, utilizing two immiscible liquids with dissimilar specific gravities in direct contact, is more efficient mechanism of heat transfer than conventional heat exchangers with walls or membranes. Concept could be adapted for collection of heat from solar or geothermal sources.

  11. Images reveal that atmospheric particles can undergo liquid-liquid phase separations

    Energy Technology Data Exchange (ETDEWEB)

    You, Yuan; Renbaum-Wolff, Lindsay; Carreras-Sospedra, Marc; Hanna, Sarah; Hiranuma, Naruki; Kamal, Saeid; Smith, Mackenzie L.; Zhang, Xiaolu; Weber, Rodney; Shilling, John E.; Dabdub, Donald; Martin, Scot T.; Bertram, Allan K.


    A large fraction of submicron atmospheric particles contains both organic material and inorganic salts. As the relative humidity cycles in the atmosphere, these mixed particles can undergo a range of phase transitions, possibly including liquid-liquid phase separation. If liquid-liquid phase separation occurs, the gas-particle partitioning of atmospheric semi-volatile organic compounds, the scattering and absorption of solar radiation, and the uptake of reactive gas species on atmospheric particles will be affected, with important implications for climate predictions. The actual occurrence of these types of phase transitions within individual atmospheric particles has been considered uncertain, in large part because of the absence of observations for real-world samples. Here, using optical and fluorescence microscopy, we observe the coexistence of two non-crystalline phases in particles generated from real-world samples collected on multiple days in Atlanta, Georgia, and in particles generated in the laboratory using atmospheric conditions. These results reveal that atmospheric particles can undergo liquid-liquid phase separations. Using a box model, we show that liquid-liquid phase separation can result in increased concentrations of gas-phase NO3 and N2O5 in the Atlanta region, due to decreased particle uptake of N2O5.

  12. Liquid helium

    CERN Document Server

    Atkins, K R


    Originally published in 1959 as part of the Cambridge Monographs on Physics series, this book addresses liquid helium from the dual perspectives of statistical mechanics and hydrodynamics. Atkins looks at both Helium Three and Helium Four, as well as the properties of a combination of the two isotopes. This book will be of value to anyone with an interest in the history of science and the study of one of the universe's most fundamental elements.

  13. 77 FR 5487 - Countervailing Duty Investigation of Crystalline Silicon Photovoltaic Cells, Whether or Not... (United States)


    ... International Trade Administration Countervailing Duty Investigation of Crystalline Silicon Photovoltaic Cells... duty (CVD) petition concerning imports of crystalline silicon photovoltaic cells, whether or not... Imposition of Antidumping and Countervailing Duties Against Crystalline Silicon Photovoltaic Cells, Whether...

  14. Comparison of the incremental and hierarchical methods for crystalline neon. (United States)

    Nolan, S J; Bygrave, P J; Allan, N L; Manby, F R


    We present a critical comparison of the incremental and hierarchical methods for the evaluation of the static cohesive energy of crystalline neon. Both of these schemes make it possible to apply the methods of molecular electronic structure theory to crystalline solids, offering a systematically improvable alternative to density functional theory. Results from both methods are compared with previous theoretical and experimental studies of solid neon and potential sources of error are discussed. We explore the similarities of the two methods and demonstrate how they may be used in tandem to study crystalline solids.

  15. Role of crystallins in ocular neuroprotection and axonal regeneration. (United States)

    Thanos, Solon; Böhm, Michael R R; Meyer zu Hörste, Melissa; Prokosch-Willing, Verena; Hennig, Maren; Bauer, Dirk; Heiligenhaus, Arndt


    Neuroprotection is an emerging challenge in ophthalmology due to the particularly exposed location of retinal neurons and to the steadily increasing rate of intraocular surgical and pharmacological treatments applied to various eye diseases. Within few decades neuroprotection has developed from strongly contested approaches to being recognized and introduced as a potentially clinical application. One of the groups of putative substances for neuroprotection comprises αA- and αB-crystallins, which are types of heat-shock proteins and are considered to be molecular chaperones. The β/γ-crystallins form their own superfamily and are characterized as proteins with a distinct structure containing four Greek key motifs. Besides being abundant in the ocular lens, crystallins are also expressed in both the developing and mature retina. Crystallins are dramatically up-regulated in numerous retinal pathologies, including mechanical injury, ischemic insults, age-related macular degeneration, uveoretinitis, and diabetic retinopathy. Crystallins of the α family are thought to play a crucial role in retinal neuron survival and inflammation. Crystallins of the β/γ superfamily are also small proteins with a possible emerging role in retinal tissue remodeling and repair. One of the typical retinal diseases associated with crystallins is the experimental glaucomatous neuropathy that is characterized by their expression. Another typical retinal disease is the atrophy that occurs after mechanical injury to the optic nerve, which is associated with the need to regrow retinal axons. We have shown in regenerative models in vivo and in vitro that βB2-crystallin actively supports the regenerative growth of cut retinal axons, thereby offering targets for neuroprotective and regenerative treatments. In this review we discuss the discovery that βB2-crystallin is clearly up-regulated in the regenerating retina in vitro. βB2-Crystallin is produced and secreted during axon elongation

  16. Shock compression of liquid hydrazine

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, B.O. [Los Alamos National Lab., NM (United States); Chavez, D.J. [Rockwell White Sands Test Facility, Las Cruces, NM (United States)


    Liquid hydrazine (N{sub 2}H{sub 4}) is a propellant used by the Air Force and NASA for aerospace propulsion and power systems. Because the propellant modules that contain the hydrazine can be subject to debris impacts during their use, the shock states that can occur in the hydrazine need to be characterized to safely predict its response. Several shock compression experiments have been conducted in an attempt to investigate the detonability of liquid hydrazine; however, the experiments results disagree. Therefore, in this study, we reproduced each experiment numerically to evaluate in detail the shock wave profiles generated in the liquid hydrazine. This paper presents the results of each numerical simulation and compares the results to those obtained in experiment. We also present the methodology of our approach, which includes chemical kinetic experiments, chemical equilibrium calculations, and characterization of the equation of state of liquid hydrazine.

  17. Triaxial Swirler Liquid Injector Development Project (United States)

    National Aeronautics and Space Administration — Sierra Engineering Inc. (Sierra) believes that the subject triaxial liquid propellant swirl injector has the potential to meet many of NASA's Earth-to-Orbit (ETO)...

  18. Crystallins in water soluble-high molecular weight protein fractions and water insoluble protein fractions in aging and cataractous human lenses. (United States)

    Harrington, Veronica; McCall, Shantis; Huynh, Sy; Srivastava, Kiran; Srivastava, Om P


    The aim of the study was to comparatively analyze crystallin fragments in the water soluble high molecular weight (WS-HMW) and in the water insoluble (WI) protein fractions of human cataractous (with nuclear opacity) and age matched normal lenses to determine the identity of crystallin species that show cataract specific changes such as truncation and post-translational modifications. Because these changes were cataract specific and not aging specific, the results were expected to provide information regarding potential mechanisms of age related cataract development. The WS-alpha-crystallin, WS-HMW protein, and WI protein fractions were isolated from normal lenses of different ages and from cataractous lenses. The three fractions were subjected to two dimensional (2D) gel electrophoresis (IEF in the first dimension and SDS-PAGE in the second dimension). Individual spots from 2D gels were trypsin digested and the tryptic fragments were analyzed by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. The 2D protein profiles of WS-alpha-crystallin fractions of normal human lenses showed an age related increase in the number of crystallin fragments. In young normal lenses, the WS-alpha-crystallin fragments were mostly C-terminally truncated, but in older lenses these were both N- and C-terminally truncated. The WS-HMW protein fraction from normal lenses contained mainly fragments of alphaA- and alphaB-crystallin, whereas additional fragments of betaB1- and betaA3-crystallin were present in this fraction from cataractous lenses. Similarly, the WI proteins in normal lenses contained fragments of alphaA- and alphaB-crystallin, but cataractous lenses contained additional fragments of betaA3- and betaB1-crystallin. The modifications identified in the WS-HMW and WI crystallin species of cataractous lenses were truncation, oxidation of Trp residues, and deamidation of Asn to Asp residues. The results show that the components of WS-HMW and

  19. Process induced disorder in crystalline materials: differentiating defective crystals from the amorphous form of griseofulvin. (United States)

    Feng, Tao; Pinal, Rodolfo; Carvajal, M Teresa


    This research investigates milling induced disorder in crystalline griseofulvin. Griseofulvin was subjected to cryogenic milling for various lengths of time. For comparison, the amorphous form of griseofulvin was also prepared by the quench melt method. Different analytical techniques were used to study the differences between the cryomilled, amorphous and crystalline forms of the drug. Cryogenic milling of griseofulvin progressively reduces the crystallinity of the drug by inducing crystal defects, rather than amorphous materials. Raman analysis provides evidence of structural differences between the two. The differences between the defective crystals produced by milling and the amorphous form are significant enough as to be measurable in their bulk thermal properties. Defective crystals show significant decrease in the heat of fusion as a function of milling time but do not exhibit a glass transition nor recrystallization from the amorphous form. Crystal defects undergo recrystallization upon heating at temperatures well below the glass transition temperature (T(g)) in a process that is separate and completely independent from the crystallization of the amorphous griseofulvin, observed above T(g). Physical mixtures of defective crystals and amorphous drug demonstrate that the thermal events associated with each form persist in the mixtures, unaffected by the presence of the other form.

  20. Phonon Modes and the Maintenance Condition of a Crystalline Beam

    CERN Document Server

    Wei, Jie; Li, Xiao-Ping; Okamoto, Hiromi; Sessler, Andrew M; Yuri, Yosuke


    Previously it has been shown that the maintenance condition for a crystalline beam requires that there not be a resonance between the crystal phonon frequencies and the frequency associated with a beam moving through a lattice of N periods. This resonance can be avoided provided the phonon frequencies are all below half of the lattice frequency. Here we make a detailed study of the phonon modes of a crystalline beam. Analytic results obtained in a “smooth approximation” using the ground-state crystalline beam structure is compared with numerical evaluation employing Fourier transform of Molecular Dynamic (MD) modes. The MD also determines when a crystalline beam is stable. The maintenance condition, when combined with either the simple analytic theory or the numerical evaluation of phonon modes, is shown to be in excellent agreement with the MD calculations of crystal stability.

  1. A pseudo-single-crystalline germanium film for flexible electronics

    Energy Technology Data Exchange (ETDEWEB)

    Higashi, H.; Yamada, S.; Kanashima, T.; Hamaya, K., E-mail: [Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan); Kasahara, K.; Park, J.-H.; Miyao, M. [Department of Electronics, Kyushu University, 744 Motooka, Fukuoka 819-0395 (Japan); Kudo, K.; Okamoto, H.; Moto, K.; Tsunoda, I. [Kumamoto National College of Technology, 2659-2 Suya, Koshi, Kumamoto 861-1102 (Japan)


    We demonstrate large-area (∼600 μm), (111)-oriented, and high-crystallinity, i.e., pseudo-single-crystalline, germanium (Ge) films at 275 °C, where the temperature is lower than the softening temperature of a flexible substrate. A modulated gold-induced layer exchange crystallization method with an atomic-layer deposited Al{sub 2}O{sub 3} barrier and amorphous-Ge/Au multilayers is established. From the Raman measurements, we can judge that the crystallinity of the obtained Ge films is higher than those grown by aluminum-induced-crystallization methods. Even on a flexible substrate, the pseudo-single-crystalline Ge films for the circuit with thin-film transistor arrays can be achieved, leading to high-performance flexible electronics based on an inorganic-semiconductor channel.

  2. Nanomembrane structures having mixed crystalline orientations and compositions

    Energy Technology Data Exchange (ETDEWEB)

    Lagally, Max G.; Scott, Shelley A.; Savage, Donald E.


    The present nanomembrane structures include a multilayer film comprising a single-crystalline layer of semiconductor material disposed between two other single-crystalline layers of semiconductor material. A plurality of holes extending through the nanomembrane are at least partially, and preferably entirely, filled with a filler material which is also a semiconductor, but which differs from the nanomembrane semiconductor materials in composition, crystal orientation, or both.

  3. Crystallinity of chitin and carbonate mineral components independently record crustacean biomineralization (United States)

    Mergelsberg, S. T.; Michel, F. M.; Mukhopadhyay, B.; Dove, P. M.


    Some of the earliest evidence for crustacean organisms is attributed to the discovery of Peytoia nathorsti, a predatory arthropod from 500 Ma (Cong, P. et al., 2014). These animals presumably began with a soft exoskeleton and evolved to fill diverse ecological niches while adopting a mineralized skeleton that is rarely preserved in its entirety (Klompmaker, A.A. et al., 2015). That is, one or more of the primary skeleton components (calcium carbonate minerals, the polysaccharide chitin, and minor proteins) were subject to decomposition during fossilization and preservation. These missing pieces present a significant obstacle to reconstructing ecosystem variability over long time periods. Our recent study of the exoskeletons from ten Malacostraca species suggests the physical and chemical structure of chitin holds promise as a secondary proxy for reconstructing skeleton reinforcement. Using high-energy X-ray diffraction and a novel Raman spectroscopy technique to enhance resolution, we determined the detailed nanostructures of chitin and the associated calcium carbonate minerals that comprise the cuticles of multiple body parts. Crab cuticles from the order Brachyura (Dungeness and Rock crabs) exhibit elevated crystallinities of the chitin and calcite in the more reinforced structures (such as the claw). In contrast, the cuticle of lobster body parts show a much greater variability of calcium carbonate crystallinity and a very consistent crystallinity of chitin. Calcite and chitin crystallinity exhibit a dependency within a species (body part to body part), but these dependencies can be different between taxa. Insights from this study suggest high resolution structural analyses hold promise for developing new proxies for the paleo-environment and paleo-ecology of specific Malacostraca animals, regardless of how well the specimen is preserved.

  4. Long range electrostatic forces in ionic liquids. (United States)

    Gebbie, Matthew A; Smith, Alexander M; Dobbs, Howard A; Lee, Alpha A; Warr, Gregory G; Banquy, Xavier; Valtiner, Markus; Rutland, Mark W; Israelachvili, Jacob N; Perkin, Susan; Atkin, Rob


    Ionic liquids are pure salts that are liquid under ambient conditions. As liquids composed solely of ions, the scientific consensus has been that ionic liquids have exceedingly high ionic strengths and thus very short Debye screening lengths. However, several recent experiments from laboratories around the world have reported data for the approach of two surfaces separated by ionic liquids which revealed remarkable long range forces that appear to be electrostatic in origin. Evidence has accumulated demonstrating long range surface forces for several different combinations of ionic liquids and electrically charged surfaces, as well as for concentrated mixtures of inorganic salts in solvent. The original interpretation of these forces, that ionic liquids could be envisioned as "dilute electrolytes," was controversial, and the origin of long range forces in ionic liquids remains the subject of discussion. Here we seek to collate and examine the evidence for long range surface forces in ionic liquids, identify key outstanding questions, and explore possible mechanisms underlying the origin of these long range forces. Long range surface forces in ionic liquids and other highly concentrated electrolytes hold diverse implications from designing ionic liquids for energy storage applications to rationalizing electrostatic correlations in biological self-assembly.

  5. Single-crystalline Ni2Ge/Ge/Ni2Ge nanowire heterostructure transistors. (United States)

    Tang, Jianshi; Wang, Chiu-Yen; Xiu, Faxian; Hong, Augustin J; Chen, Shengyu; Wang, Minsheng; Zeng, Caifu; Yang, Hong-Jie; Tuan, Hsing-Yu; Tsai, Cho-Jen; Chen, Lih Juann; Wang, Kang L


    In this study, we report on the formation of a single-crystalline Ni(2)Ge/Ge/Ni(2)Ge nanowire heterostructure and its field effect characteristics by controlled reaction between a supercritical fluid-liquid-solid (SFLS) synthesized Ge nanowire and Ni metal contacts. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies reveal a wide temperature range to convert the Ge nanowire to single-crystalline Ni(2)Ge by a thermal diffusion process. The maximum current density of the fully germanide Ni(2)Ge nanowires exceeds 3.5 × 10(7) A cm(-2), and the resistivity is about 88 μΩ cm. The in situ reaction examined by TEM shows atomically sharp interfaces for the Ni(2)Ge/Ge/Ni(2)Ge heterostructure. The interface epitaxial relationships are determined to be [Formula: see text] and [Formula: see text]. Back-gate field effect transistors (FETs) were also fabricated using this low resistivity Ni(2)Ge as source/drain contacts. Electrical measurements show a good p-type FET behavior with an on/off ratio over 10(3) and a one order of magnitude improvement in hole mobility from that of SFLS-synthesized Ge nanowire.

  6. Highly crystalline inverse opal transition metal oxides via a combined assembly of soft and hard chemistries. (United States)

    Orilall, M Christopher; Abrams, Neal M; Lee, Jinwoo; DiSalvo, Francis J; Wiesner, Ulrich


    A combined assembly of soft and hard chemistries is employed to generate highly crystalline three-dimensionally ordered macroporous (3DOM) niobia (Nb2O5) and titania (TiO2) structures by colloidal crystal templating. Polystyrene spheres with sp2 hybridized carbon are used in a reverse-template infiltration technique based on the aqueous liquid phase deposition of the metal oxide in the interstitial spaces of a colloidal assembly. Heating under inert atmosphere as high as 900 degrees C converts the polymer into sturdy carbon that acts as a scaffold and keeps the macropores open while the oxides crystallize. Using X-ray diffraction it is demonstrated that for both oxides this approach leads to highly crystalline materials while heat treatments to lower temperatures commonly used for polymer colloidal templating, in particular for niobia, results in only weakly crystallized materials. Furthermore it is demonstrated that heat treatment directly to higher temperatures without generating the carbon scaffold leads to a collapse of the macrostructure. The approach should in principle be applicable to other 3DOM materials that require heat treatments to higher temperatures.

  7. Ce{sup 3+}-doped crystalline garnet films - scintillation characterization using {alpha}-particle excitation

    Energy Technology Data Exchange (ETDEWEB)

    Mares, Jiri A., E-mail: amares@fzu.c [Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 162 53 Prague 6 (Czech Republic); Prusa, Petr [Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 162 53 Prague 6 (Czech Republic); Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University, Brehova 7, 115 19 Prague 1 (Czech Republic); Nikl, Martin; Nitsch, Karel; Beitlerova, Alena [Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 162 53 Prague 6 (Czech Republic); Kucera, Miroslav; Hanus, Martin [Charles University, Faculty of Mathematics and Physics, Ke Karlovu 5, 121 16 Prague 2 (Czech Republic); Zorenko, Yurij [Laboratory of Optoelectronic Materials, Department of Electronics, Ivan Franko National University of Lviv, 107 Gen. Tarnavskogo Str. (Ukraine)


    Scintillating properties of Ce{sup 3+}-doped (Lu,Y) aluminum garnet single crystalline films (SCF) were investigated. Thin SCF films of thickness between 1 and 30 {mu}m were grown by a liquid phase epitaxy (LPE) method in various fluxes. The {alpha}-particle excitation (mainly 5.4857 MeV line of {sup 241}Am) of pulse height spectra is used to measure scintillation response of SCF, especially peak of those {alpha}-rays which are totally absorbed in the films. Detailed studies and evaluation of scintillation measurements of large sets of Ce{sup 3+}-doped SCF (Lu,Y) aluminum garnets showed that at present time (i) YAG:Ce SCF have comparable scintillation properties as YAG:Ce single crystals, especially their N{sub phels} photoelectron yields are the same while (ii) scintillation properties of LuAG:Ce SCF do not reach those of LuAG:Ce single crystal.

  8. Controlling the Properties of a Liquid Crystalline Epoxy Though Magnetic Field Processing

    National Research Council Canada - National Science Library

    Lincoln, Derek


    .... Magnetic field processing imparts a degree of macromolecular anisotropy on the material. This anisotropy has been shown to cause a favorable change in some of these mechanical and physical properties...

  9. A study of the physical properties of lamellar liquid-crystalline dispersions

    NARCIS (Netherlands)

    Pas, Johannes Cornelis van de


    Important questions addressed in this thesis are (i) which are the factors governing the physical stability of these dispersions and (ii) what is the relation between the chemical composition of the surfactant and the physical stability of these systems as a function of electrolyte type and

  10. Liquid crystalline phases of dendritic lipid-DNA self-assemblies: lamellar, hexagonal, and DNA bundles. (United States)

    Zidovska, Alexandra; Evans, Heather M; Ewert, Kai K; Quispe, Joel; Carragher, Bridget; Potter, Clinton S; Safinya, Cyrus R


    The prospects of gene therapy have generated unprecedented interest in the properties and structures of complexes of nucleic acids (NAs) with cationic liposomes (CLs), which are used as nonviral NA carriers in worldwide clinical trials. An improved understanding of the mechanisms of action of CL-NA complexes is required to enable their widespread therapeutic use. In prior studies of CL-mediated DNA delivery, membrane charge density (sigma(M)) was identified as a key parameter for transfection efficiency (TE) of lamellar (L(alpha)(C)) CL-DNA complexes. The TE of CL-DNA complexes containing cationic lipids with headgroup valencies from 1+ to 5+ follows a universal bell-shaped curve as a function of sigma(M). As we report here, the TE of CL-DNA complexes containing new multivalent lipids with dendritic headgroups (DLs) strongly deviates from this curve at high sigma(M). We have investigated four DLs, MVLG2 (4+), MVLG3 (8+), MVLBisG1 (8+), and MVLBisG2 (16+), in mixtures with neutral 1,2-dioleoyl-sn-glycerophosphatidyl-choline (DOPC). To understand the TE behavior, we have performed X-ray diffraction (XRD), optical microscopy, and cryo-TEM studies of the DL/DOPC mixtures and their DNA complexes. XRD reveals a complex phase behavior of DL-DNA complexes which strongly depends on the headgroup charge. MVLG2(4+)/DOPC-DNA complexes exhibit the lamellar phase at all molar fractions of DL, Phi(DL). In stark contrast, MVLBisG2(16+)/ DOPC-DNA complexes remain lamellar only for Phi(DL) phase H(I)(C), consisting of a hexagonal lattice of cylindrical lipid micelles and a DNA honeycomb lattice, is formed. At Phi(DL) > 0.3, XRD suggests formation of a distorted H(I)(C) phase. For Phi(DL) > or = 0.5 under high salt conditions, this phase coexists with a bundle phase of DNA condensed by the depletion-attraction effect of DL micelles. The transitions at high sigma(M) from the lamellar phase to the new hexagonal phases of DL-DNA complexes coincide with the deviation from the universal TE behavior of lamellar complexes. The observed high TE, which is independent of sigma(M), strongly suggests a novel mechanism of action for these DL-DNA complex phases.

  11. Selectively deuterated liquid crystalline cyanoazobenzene side-chain polyesters. 2. Preparation and characterization of polyesters

    DEFF Research Database (Denmark)

    Kulinna, Christian; Hvilsted, Søren; Hendann, Claudia


    calorimetry. Whereas the polytetradecanedioates show a complex thermal behaviour with a number of different phases, the polyadipates are less complex and both nematic and smectic A phases have been identified by polarizing optical microscopy. Solution 1H, 13C and 2H NMR spectroscopy have been utilized......Two sets of specifically deuterated cyanoazobenzene side-chain polyadipates and polytetrade-canedioates have been prepared by transesterification in the melt. Combinations of three different, selectively deuterium labeled 2-[6-[4-[(4-cyanophenyl)azo]phenoxy]hexyl]-1,3-propanediols or the non...... for both polyester structural assessment and determination of deuterium distribution and content. FTIR spectroscopy has revealed suitable and characteristic vibrations which unequivocally represents the absorption behaviour of individual polyester segments or molecular structures in the different...

  12. Synthesis and characterization of inorganic materials precipitated into polymeric and novel liquid crystalline systems (United States)

    Lubeck, Christopher Ryan

    The use of nanostructured, hybrid materials possesses great future potential. Many examples of nanostructured materials exist within nature, such as animal bone, animal teeth, and seashells. This research, inspired by nature, strove to mimic salient properties of natural materials, utilizing methods observed within nature to produce materials. Further, this research increased the functionality of the templates from "mere" template to functional participant. Different chemical methods to produce hybrid materials were employed within this research to achieve these goals. First, electro-osmosis was utilized to drive ions into a polymeric matrix to form hybrid inorganic polymer material, creating a material inspired by naturally occurring bone or seashell in which the inorganic component provides strength and the polymeric material decreases the brittleness of the combined hybrid material. Second, self-assembled amphiphiles, forming higher ordered structures, acted as a template for inorganic cadmium sulfide. Electronically active molecules based on ethylene oxide and aniline segments were synthesized to create interaction between the templating material and the resulting inorganic cadmium sulfide. The templating process utilized self-assembly to create the inorganic structure through the interaction of the amphiphiles with water. The use of self-assembly is itself inspired by nature. Self-assembled structures are observed within living cells as cell walls and cell membranes are created through hydrophilic and hydrophobic interactions. Finally, the mesostructured inorganic cadmium sulfide was itself utilized as a template to form mesostructured copper sulfide.

  13. Meso-epitaxial solution-growth of self-organizing discotic liquid-crystalline semiconductors

    DEFF Research Database (Denmark)

    Craats, A.M. van de; Stutzmann, N.; Bunk, Oliver


    Substituted hexabenzocoronenes (HBCs) form films with supramolecularly ordered columnar stacks that are uniaxially oriented onto poly(tetrafluoroethylene) alignment layers (see Figure). In field-effect transistor (FET) tests, mobilities of up to 10–3 cm2V–1s–1 and high on–off ratios of more than ...... 104 were derived for these aligned HBC films, characteristics superior to FETs prepared from isotropic HBC layers....

  14. Unidirectional rotary motion in a liquid crystalline environment : Color tuning by a molecular motor

    NARCIS (Netherlands)

    Delden, Richard A. van; Koumura, Nagatoshi; Harada, Noboyuki; Feringa, Bernard


    Life could not exist without motion induced by a variety of molecular motors. The construction of artificial motors by chemical synthesis, which can power motions that lead to macroscopic detectable effects in a system, is a major endeavor in contemporary science. To move toward this goal, a

  15. Electro-Optically Active Monomers: Synthesis and Characterization of Thin Films of Liquid Crystalline Substituted Polyacetylenes (United States)

    Duran, R. S.


    The overall objective of this study was the description of the behavior of mesogen substituted acetylene monomers and polymers in monolayer films at the air/water interface and as multilayer films including the formation of such films. Fundamental knowledge to be gained would include the effect of balancing hydrophilic and hydrophobic tendencies in a molecule more complex than the classical fatty acids or lipids. The effect of molecular shape on the packing and thus the ultimate stability of monolayers formed from these new molecules was explored. The work takes on the challenge of preorienting monomers in well-ordered arrays prior to attempting polymerization with the hope that order would be preserved in any resulting polymer. New knowledge gained with regard to the acetylenic monomers includes processing of the acetylene monomer into multi-layer films, followed by the design and synthesis of a second generation of improved monomer structure for superior LBK film transfer properties. A third generation of acetylenic monomer was synthesized which approaches more closely the goal of solid state polymerization of these materials. A parallel study took a different approach. The materials are pre-formed poly(phenylene-acetylene) polymers so questions about reactivity are mute. The materials are a variation on the well-known hairy-rod polymers with regard to their Langmuir film-forming properties. Overall, the goal was to demonstrate that these polymers could be processed into NLO materials with novel polar order.

  16. Antimicrobial Peptide-Driven Colloidal Transformations in Liquid-Crystalline Nanocarriers

    DEFF Research Database (Denmark)

    Gontsarik, Mark; Buhmann, Matthias T; Yaghmur, Anan


    Designing efficient colloidal systems for the delivery of membrane active antimicrobial peptides requires in-depth understanding of their structural and morphological characteristics. Using dispersions of inverted type bicontinuous cubic phase (cubosomes), we examine the effect of integrating...... guide the design of new nanocarriers for antimicrobial peptides and may provide essential knowledge on the mechanisms underlying the bacterial membrane disruption with peptide-loaded nanostructures....... the amphiphilic peptide LL-37 at different concentrations on the self-assembled structure and evaluate its bactericidal ability against Escherichia coli. Small-angle X-ray scattering, dynamic light scattering, and cryogenic transmission electron microscopy show that LL-37 integrates into the bicontinuous cubic...

  17. Effect of heat and film thickness on a photoinduced phase transition in azobenzene liquid crystalline polyesters

    DEFF Research Database (Denmark)

    Sanchez, C; Alcala, R; Hvilsted, Søren


    . Optical absorption measurements show that azobenzene aggregates present in one of the polymers are broken down in the photoinduced phase transition. The birefringence induced with low power 488 nm light in films before and after undergoing that photoinduced phase transition has also been studied...

  18. Endgroups of Functionalized Siloxane Oligomers Direct Block Copolymeric or Liquid Crystalline Self-Assembly Behavior

    NARCIS (Netherlands)

    Zha, R. Helen; De Waal, Bas; Lutz, Martin|info:eu-repo/dai/nl/304828971; Teunissen, Abraham J.p.; Meijer, E. W.


    Monodisperse oligodimethylsiloxanes end-functionalized with the hydrogen-bonding ureidopyrimidinone (UPy) motif undergo phase separation between their aromatic end groups and dimethylsiloxane midblocks to form ordered nanostructures with domain spacings of <5 nm. The self-assembly behavior of these

  19. Proton-exchange biomimetic membranes based on columnar side-chain liquid-crystalline polyethers


    Bhosale, Suryakant


    En este proyecto de tesis, se han sintetizado y caracterizado familias de poliéteres cristal líquidode cadena lateral obtenidos a partir de poliepiclorhidrina, poli (óxido de epiclorhidrina-co-etileno) o poliglicidol lineal,que se auto-ensamblan en estructuras supramoleculares. Se obtuvieron diferentes tipos de mesofases y diferentes rangos de estabilidad en función del grado de modificación alcanzado. Para la obtención de membranas orientadas transportadoras de protones a partir de estos p...

  20. High Performance Liquid Crystalline Polymers from 2,5- furandicarboxylic acid; : Synthesis, Characterization and Properties

    NARCIS (Netherlands)

    Wilsens, Karel


    Thermotropic polyesters are an important class of materials for high performance applications.Their low melt viscosities, low thermal expansion coefficients, high use temperatures, and ease in processing allow for the production of high strength and high modulus fibers, films, or compressionmolded