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Sample records for lyotropic chromonic liquid

  1. Chirality Amplification in Tactoids of Lyotropic Chromonic Liquid Crystals

    Science.gov (United States)

    Peng, Chenhui; Lavrentovich, Oleg

    2014-03-01

    We demonstrate an effective chirality amplification based on the long-range forces, extending over the scales of tens of micrometers, much larger than the single molecule (nanometer) scale. The mechanism is rooted in the long-range elastic nature of orientational order in lyotropic chromonic liquid crystals (LCLCs) that represent water solutions of achiral disc-like molecules. Minute quantities of chiral molecules such as amino acid L-alanine and limonene added to the droplets of LCLC lead to chiral amplification characterized by an increase of optical activity by a factor of 103 - 104. This effect allows one to discriminate and detect the absolute configuration of chiral molecules in an aqueous system, thus opening new possibilities in biosensing and other biological applications.

  2. Adding Mono- and Multivalent Ions to Lyotropic Chromonic Liquid Crystals

    Science.gov (United States)

    Tortora, Luana; Park, Heung-Shik; Antion, Kelly; Woolwerton, Chris; Finotello, Daniele; Lavrentovich, Oleg

    2006-03-01

    Lyotropic Chromonic Liquid Crystals (LCLCs) are a distinct class of liquid crystals formed in aqueous solutions by molecules with rigid polyaromatic cores and ionic groups at the periphery [1-4]. The phase diagrams of these materials should depend on entropic factors (as in the Onsager model) and electrostatic interactions. Using optical polarizing microscopy, we studied the effects of mono- and multivalent ions on the phase diagrams of Blue 27 [3] and Sunset Yellow [2]. The monovalent ions change the temperatures of phase transitions, as described in [4], while the effect of multivalent ions is more dramatic and, in addition to the changed temperatures of phase transitions by tens of degrees, it often involves condensation of LCLC aggregates into domains with birefringence much higher than that in a normal nematic phase. Work supported by OBR B-7844. [1]J. Lydon, Current Opin. Colloid & Interface Sci. 3, 458 (1998);8, 480-489 (2004); [2]V. R. Horowitz, L. A. Janowitz, A. L. Modic, P. J. Heiney, and P. J. Collings, 2005, Phys. Rew. E 72, 041710; [3]Yu. A. Nastishin, H. Liu, T. Schneider, T., V. Nazarenko, R. Vasyuta, S. V. Shiyanovskii, and O. D. Lavrentovich, 2005, Phys. Rev. E 72, 041711; [4]A.F. Kostko, B. H. Cipriano, O. A. Pinchuk, L. Ziserman, M. A. Anisimov, D. Danino, and S. R. Raghavan. J. Phys. Chem. B 109, 19126-19133 (2005)

  3. Effect of ionic additives on elasticity of lyotropic chromonic liquid crystal

    Science.gov (United States)

    Zhou, Shuang; Cervenka, Adam J.; Singh, Yogesh; Tortora, Luana T.; Almasan, Carmen C.; Lavrentovich, Oleg D.

    2013-03-01

    Using a magnetic Frederiks transition technique, we determine how the splay K1 and bend K3 elastic constants of lyotropic chromonic liquid crystal Sunset Yellow (SSY) depend on concentration of ionic additives, sodium chloride (NaCl) and magnesium sulfate (MgSO4). Both salts increase the ratio K1 /K3 , by mainly increasing K1 (MgSO4) or mainly decreasing K3 (NaCl). The effects are attributed to the screening of electrostatic repulsions of chromonic molecules, which is expected to increase the contour length (thus increasing K1) and to decrease the persistence length (thus decreasing K3) of the chromonic aggregates in which the molecules are stacked face-to-face. As in salt-free SSY, the ratio K1 /K3 increases when the temperature decreases. The work was supporeted by NSF grants DMR 1104850 and 11212878.

  4. Elasticity of lyotropic chromonic liquid crystal Sunset Yellow probed by magnetic Frederiks transition

    Science.gov (United States)

    Zhou, Shuang; Nastishin, Yu. A.; Omelchenko, M. M.; Tortora, L.; Nazarenko, V. G.; Boiko, O. P.; Ostapenko, T.; Sprunt, S. N.; Gleeson, J. T.; Lavrentovich, O. D.

    2012-02-01

    By using director reorientation in the magnetic field, we determine the concentration and temperature dependencies of the splay K1, twist K2, and bend K3 elastic constants (normalized by the anisotropy of the diamagnetic susceptibility) for a nematic lyotropic chromonic liquid crystal (LCLC) Sunset Yellow. In a sharp contrast to thermotropic liquid crystals, the Frederiks effects in LCLC show a hysteresis, which is more pronounced at high concentration and low temperatures. We attribute the hysteresis to the changes in self-assembled structure of LCLC aggregates under the influence of field-imposed deformations.

  5. Lyotropic chromonic liquid crystals: From viscoelastic properties to living liquid crystals

    Science.gov (United States)

    Zhou, Shuang

    Lyotropic chromonic liquid crystal (LCLC) represents a broad range of molecules, from organic dyes and drugs to DNA, that self-assemble into linear aggregates in water through face-to-face stacking. These linear aggregates of high aspect ratio are capable of orientational order, forming, for example nematic phase. Since the microscopic properties (such as length) of the chromonic aggregates are results of subtle balance between energy and entropy, the macroscopic viscoelastic properties of the nematic media are sensitive to change of external factors. In the first part of this thesis, by using dynamic light scattering and magnetic Frederiks transition techniques, we study the Frank elastic moduli and viscosity coefficients of LCLC disodium cromoglycate (DSCG) and sunset yellow (SSY) as functions of concentration c , temperature T and ionic contents. The elastic moduli of splay (K1) and bend (K3) are in the order of 10pN, about 10 times larger than the twist modulus (K2). The splay modulus K1 and the ratio K1/K3 both increase substantially as T decreases or c increases, which we attribute to the elongation of linear aggregates at lower T or higher c . The bend viscosity is comparable to that of thermotropic liquid crystals, while the splay and twist viscosities are several orders of magnitude larger, changing exponentially with T . Additional ionic additives into the system influence the viscoelastic properties of these systems in a dramatic and versatile way. For example, monovalent salt NaCl decreases bend modulus K3 and increases twist viscosity, while an elevated pH decreases all the parameters. We attribute these features to the ion-induced changes in length and flexibility of building units of LCLC, the chromonic aggregates, a property not found in conventional thermotropic and lyotropic liquid crystals form by covalently bound units of fixed length. The second part of the thesis studies a new active bio-mechanical hybrid system called living liquid crystal

  6. Elasticity, viscosity, and orientational fluctuations of a lyotropic chromonic nematic liquid crystal disodium cromoglycate.

    Science.gov (United States)

    Zhou, Shuang; Neupane, Krishna; Nastishin, Yuriy A; Baldwin, Alan R; Shiyanovskii, Sergij V; Lavrentovich, Oleg D; Sprunt, Samuel

    2014-09-14

    Using dynamic light scattering, we study orientational fluctuation modes in the nematic phase of a self-assembled lyotropic chromonic liquid crystal (LCLC) disodium cromoglycate and measure the Frank elastic moduli and viscosity coefficients. The elastic moduli of splay (K1) and bend (K3) are in the order of 10 pN while the twist modulus (K2) is an order of magnitude smaller. The splay constant K1 and the ratio K1/K3 both increase substantially as the temperature T decreases, which we attribute to the elongation of the chromonic aggregates at lower temperatures. The bend viscosity is comparable to that of thermotropic liquid crystals, while the splay and twist viscosities are several orders of magnitude larger. The temperature dependence of bend viscosity is weak. The splay and twist viscosities change exponentially with the temperature. In addition to the director modes, the fluctuation spectrum reveals an additional mode that is attributed to diffusion of structural defects in the column-like aggregates.

  7. Self-assembly, Condensation, and Order in Aqueous Lyotropic Chromonic Liquid Crystals Crowded with Additives

    Energy Technology Data Exchange (ETDEWEB)

    Tortora, L.; Park, H; Kang, S; Savaryn, V; Hong, S; Kaznatcheev, K; Finotello, D; Sprunt, S; Kumar, S; Lavrentovich, O

    2010-01-01

    Dense multicomponent systems with macromolecules and small solutes attract a broad research interest as they mimic the molecularly crowded cellular interiors. The additives can condense and align the macromolecules, but they do not change the degree of covalent polymerization. We chose a lyotropic chromonic liquid crystal with reversibly and non-covalently assembled aggregates as a much softer system, reminiscent of 'living polymers', to demonstrate that small neutral and charged additives cause condensation of aggregates with ensuing orientational and positional ordering and nontrivial morphologies of phase separation, such as tactoids and toroids of the nematic and hexagonal columnar phase coexisting with the isotropic melt. Scanning transmission X-ray microscopy (STXM) with near edge X-ray absorption fine structure (NEXAFS) analysis as well as fluorescent microscopy demonstrates segregation of the components. The observations suggest that self-assembly of chromonic aggregates in the presence of additives is controlled by both entropy effects and by specific molecular interactions and provide a new route to the regulated reversible assembly of soft materials formed by low-molecular weight components.

  8. Self-assembly, condensation, and order in aqueous lyotropic chromonic liquid crystals crowded with additives

    Energy Technology Data Exchange (ETDEWEB)

    Tortora, Luana; Park, Heung-Shik; Kang, Shin-Woong; Savaryn, Victoria; Hong, Seung-Ho; Kaznatcheev, Konstantine; Finotello, Daniele; Sprunt, Samuel; Kumar, Satyendra; Lavrentovich, Oleg D. (Chonbuk); (Kent); (BNL)

    2012-09-06

    Dense multicomponent systems with macromolecules and small solutes attract a broad research interest as they mimic the molecularly crowded cellular interiors. The additives can condense and align the macromolecules, but they do not change the degree of covalent polymerization. We chose a lyotropic chromonic liquid crystal with reversibly and non-covalently assembled aggregates as a much softer system, reminiscent of 'living polymers', to demonstrate that small neutral and charged additives cause condensation of aggregates with ensuing orientational and positional ordering and nontrivial morphologies of phase separation, such as tactoids and toroids of the nematic and hexagonal columnar phase coexisting with the isotropic melt. Scanning transmission X-ray microscopy (STXM) with near edge X-ray absorption fine structure (NEXAFS) analysis as well as fluorescent microscopy demonstrates segregation of the components. The observations suggest that self-assembly of chromonic aggregates in the presence of additives is controlled by both entropy effects and by specific molecular interactions and provide a new route to the regulated reversible assembly of soft materials formed by low-molecular weight components.

  9. Optical characterization of the nematic lyotropic chromonic liquid crystals: light absorption, birefringence, and scalar order parameter.

    Science.gov (United States)

    Nastishin, Yu A; Liu, H; Schneider, T; Nazarenko, V; Vasyuta, R; Shiyanovskii, S V; Lavrentovich, O D

    2005-10-01

    We report on the optical properties of the nematic (N) phase formed by lyotropic chromonic liquid crystals (LCLCs) in well aligned planar samples. LCLCs belong to a broad class of materials formed by one-dimensional molecular self-assembly and are similar to other systems such as "living polymers" and "wormlike micelles." We study three water soluble LCLC forming materials: disodium chromoglycate, a derivative of indanthrone called Blue 27, and a derivative of perylene called Violet 20. The individual molecules have a planklike shape and assemble into rodlike aggregates that form the phase once the concentration exceeds about 0.1 M. The uniform surface alignment of the N phase is achieved by buffed polyimide layers. According to the light absorption anisotropy data, the molecular planes are on average perpendicular to the aggregate axes and thus to the nematic director. We determined the birefringence of these materials in the N and biphasic N-isotropic (I) regions and found it to be negative and significantly lower in the absolute value as compared to the birefringence of typical thermotropic low-molecular-weight nematic materials. In the absorbing materials Blue 27 and Violet 20, the wavelength dependence of birefringence is nonmonotonic because of the effect of anomalous dispersion near the absorption bands. We describe positive and negative tactoids formed as the nuclei of the new phase in the biphasic N-I region (which is wide in all three materials studied). Finally, we determined the scalar order parameter of the phase of Blue 27 and found it to be relatively high, in the range 0.72-0.79, which puts the finding into the domain of general validity of the Onsager model. However, the observed temperature dependence of the scalar order parameter points to the importance of factors not accounted for in the athermal Onsager model, such as interaggregate interactions and the temperature dependence of the aggregate length.

  10. Self-Assembly of Lyotropic Chromonic Liquid Crystal Sunset Yellow and Effects of Ionic Additives

    Energy Technology Data Exchange (ETDEWEB)

    Park, Heung-Shik; Kang, Shin-Woong; Tortora, Luana; Nastishin, Yuriy; Finotello, Daniele; Kumar, Satyendra; Lavrentovich, Oleg D. (NSF); (Institute of Physical Optics, Ukraine); (Kent)

    2008-12-22

    Lyotropic chromonic liquid crystals (LCLCs) are formed by molecules with ionic groups at the periphery that associate into stacks through noncovalent self-assembly while in water. The very existence of the nematic (N) phase in the typical LCLC, the dye Sunset Yellow (SSY) is a puzzle, as the correlation length associated with the stacking, as measured in the X-ray experiments, is too short to explain the orientational order by the Onsager model. We propose that the aggregates can be more complex than simple rods and contain 'stacking faults' such as junctions with a shift of neighboring molecules, 3-fold junctions, etc. We study how ionic additives, such as salts of different valency and pH-altering agents, alter the N phase of SSY purified by recrystallization. The additives induce two general trends: (a) stabilization of the N phase, caused by the mono and divalent salts (such as NaCl), and evidenced by the increase of the N-to-I transition temperature and the correlation length; (b) suppression of the N phase manifested in the decrease of the N-to-I transition temperature and in separation of the N phase into a more densely packed N phase or the columnar (C) phase, coexisting with a less condensed I phase. The scenario (b) can be triggered by simply increasing pH (adding NaOH). The effects produced by tetravalent spermine fall mostly into the category (b), but the detail depends on whether this additive is in its salt form or a free base form. The base form causes changes through changes in pH and possible excluded volume effects whereas the salt form might disrupt the structure of SSY aggregates.

  11. Condensation of Self-Assembled Lyotropic Chromonic Liquid Crystal Sunset Yellow in Aqueous Solutions Crowded with Polyethylene Glycol and Doped with Salt

    Energy Technology Data Exchange (ETDEWEB)

    Park, Heung-Shik; Kang, Shin-Woong; Tortora, Luana; Kumar, Satyendra; Lavrentovich, Oleg D. (Chonbuk); (Kent)

    2012-10-10

    We use optical and fluorescence microscopy, densitometry, cryo-transmission electron microscopy (cryo-TEM), spectroscopy, and synchrotron X-ray scattering to study the phase behavior of the reversible self-assembled chromonic aggregates of an anionic dye Sunset Yellow (SSY) in aqueous solutions crowded with an electrically neutral polymer polyethylene glycol (PEG) and doped with the salt NaCl. PEG causes the isotropic SSY solutions to condense into a liquid-crystalline region with a high concentration of SSY aggregates, coexisting with a PEG-rich isotropic (I) region. PEG added to the homogeneous nematic (N) phase causes separation into the coexisting N and I domains; the SSY concentration in the N domains is higher than the original concentration of PEG-free N phase. Finally, addition of PEG to the highly concentrated homogeneous N phase causes separation into the coexisting columnar hexagonal (C) phase and I phase. This behavior can be qualitatively explained by the depletion (excluded volume) effects that act at two different levels: at the level of aggregate assembly from monomers and short aggregates and at the level of interaggregate packing. We also show a strong effect of a monovalent salt NaCl on phase diagrams that is different for high and low concentrations of SSY. Upon the addition of salt, dilute I solutions of SSY show appearance of the condensed N domains, but the highly concentrated C phase transforms into a coexisting I and N domains. We suggest that the salt-induced screening of electric charges at the surface of chromonic aggregates leads to two different effects: (a) increase of the scission energy and the contour length of aggregates and (b) decrease of the persistence length of SSY aggregates.

  12. Research on colored lyotropic liquid crystals

    Institute of Scientific and Technical Information of China (English)

    WEI Xilian; YIN Baolin; SUN Dezhi; LIU Jie; WANG Zhongni; LI Ganzuo

    2005-01-01

    Splendidly colored lyotropic liquid crystals formed in the ternary system of a novel cationic surfactant, 3-p-nonylphenoxy-2-hydroxypropyl trimethyl ammonium bromide (NPTAB)-n-butanol-water system, had been observed under polarized light microscope. Small-angle X-ray scattering (SAXS), 2H (deuterium) quadrupolar splitting (2H NMR) were employed to confirm the structures of these liquid crystals. The structural transformation of these special lyotropic liquid crystals had been confirmed by differential scanning calorimetry (DSC). The influences of liquid crystal film thickness, temperature and conserving time on the color of liquid crystals have been investigated. It is also theoretically discussed for forming and changing of liquid crystal color.

  13. Drying, phase separation, and deposition in droplets of sunset yellow chromonic liquid crystal

    Science.gov (United States)

    Gross, Adam; Davidson, Zoey S.; Huang, Yongyang; Still, Tim; Zhou, Chao; Yodh, A. G.

    We investigate the drying process and the final deposition patterns of multi-phase sessile droplets containing aqueous lyotropic chromonic liquid crystal (LC). The experiments employ a variety of optical techniques including profilometry, polarization optical microscopy and optical coherence microscopy. An unusual hierarchical LC assembly is observed during drying; in particular, LC mesogens are first formed at the start of drying and then compartments of isotropic, nematic and columnar phases arise. Nonuniform evaporation creates concentration gradients in droplets such that LC phases emerge from the outer edge of the drop and advance to the center over the course of drying. Distinct outward flows associated with the ``coffee-ring effect'' are seen initially, but the assembly of the mesogens creates viscosity, density, and surface tension gradients that effectively introduce new convective flows and complex LC phase boundaries within the drop. Finally, we show that the final deposit shape of chromonic materials changes with rate of evaporation. We gratefully acknowledge financial support through NSF DMR12-05463, MRSEC DMR11-20901, NASA NNX08AO0G, and NSF DBI-1455613.

  14. Chromones.

    Science.gov (United States)

    Edwards, Alan M

    2014-01-01

    The chromones are a class of chemical compounds characterised by the presence of the structure 5:6 benz-1:4-pyrone in their chemical make-up. The first chromone in clinical use, khellin, was extracted from the seeds of the plant Ammi visnaga, and had been used for centuries as a diuretic and as a smooth muscle relaxant. Its use in bronchial asthma was reported in 1947. In the 1950s, Benger's Laboratories embarked on a research programme to synthesise and develop modifications of khellin for the treatment of asthma. New compounds were screened using animal models to test the ability of the compound to prevent the anaphylactic release of histamine and SRS-A (leukotrienes) from sensitised guinea pig lung, and a human model to check the ability to reduce the bronchoconstriction induced by inhaled antigen bronchial challenge. For initial screening the human work was undertaken by Dr. R.E.C. Altounyan, who suffered from allergic bronchial asthma and was employed by Benger's Laboratories. After 8 years and more than 600 challenges using over 200 compounds, in 1965 Altounyan arrived at disodium cromoglycate (DSCG), the chromone that met the criteria of providing more than 6 h of protection. DSCG is still used today as a mast cell stabiliser. © 2014 S. Karger AG, Basel.

  15. LYOTROPIC LIQUID CRYSTALLINE BEHAVIOR OF FIVE CHITOSAN DERIVATIVES

    Institute of Scientific and Technical Information of China (English)

    Yan-ming Dong; Zhi-qiang Li

    1999-01-01

    Five chitosan derivatives, i.e. O-butyryl chitosan, O-benzoyl chitosan, N-phthaloyl chitosan, N-maleoyl chitosan and O-cyanoethyl chitosan, were prepared from chitosan. All of them had better solubilitythan chitosan, and demonstrated lyotropic liquid crystalline behavior in various solvents. The critical liquid crystalline behavior of three O-substituted chitosan derivatives was evidently different from two Nsubstituted analogues. Typical fingerprint textures of cholesteric phase were only observed in three Osubstituted derivatives. The critical concentration (v/v%) of three O-substituted derivatives does not depend on the acidity of acidic solvents.

  16. Lyotropic Liquid Crystal Phases from Anisotropic Nanomaterials

    Directory of Open Access Journals (Sweden)

    Ingo Dierking

    2017-10-01

    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.

  17. Self-Assembled Supramolecular Architectures Lyotropic Liquid Crystals

    CERN Document Server

    Garti, Nissim

    2012-01-01

    This book will describe fundamentals and recent developments in the area of Self-Assembled Supramolecular Architecture and their relevance to the  understanding of the functionality of  membranes  as delivery systems for active ingredients. As the heirarchial architectures determine their performance capabilities, attention will be paid to theoretical and design aspects related to the construction of lyotropic liquid crystals: mesophases such as lamellar, hexagonal, cubic, sponge phase micellosomes. The book will bring to the reader mechanistic aspects, compositional c

  18. Secondary and lyotropic liquid crystal membranes for improved aqueous separations

    Science.gov (United States)

    Nemade, Parag Ramesh

    An effective membrane separation process should have high flux (i.e., volume filtered per unit membrane surface area per unit time) and selectivity (i.e., passage of the desired species and rejection of undesired species). This dissertation examined two approaches, secondary membranes and lyotropic liquid crystal membranes, for improving flux and selectivity in aqueous liquid separations. The first part of my work emphasizes the use of pre-deposited secondary membranes and backflushing for controlling membrane fouling in microfiltration and ultrafiltration of biological mixtures. Use of secondary membranes increased the permeate flux in microfiltration by several fold. Protein transmission is also enhanced due to the presence of the secondary membrane, and the amount of protein recovered is more than twice that obtained during filtration of protein-only solutions under otherwise identical conditions. In ultrafiltration, the flux enhancement due to secondary membranes is 50%, or less. For the second part of my research, I developed and evaluated polymerized lyotropic liquid crystal (LLC) thin-film composite membranes. LLC assemblies provide an opportunity to make nanoporous polymer membranes with precise control over chemical and structural features on the nanometer scale, which is currently lacking in commercial reverse osmosis (RO) and nanofiltration (NF) membranes available today. These LLC composite membranes are prepared by photopolymerization of solution-cast films of LLC monomer on an ultrafiltration support membrane. These LLC membranes appeared to exhibit almost linearly increasing ionic rejection based on ionic diameter. LLC monomer was modified to achieve a 15% reduction in channel diameter, through the use of a larger multivalent Eu3+ cation as the carboxylate counterion. However, the monomers synthesized required use of solvents such as tetrahydrofuran, which resulted in the dissolution and damage of the support membranes used. Therefore, this direction

  19. Influence of Proton and Salt Concentration on the Chromonic Liquid Crystal Phase Diagram of Disodium Cromoglycate Solutions: Prospects and Limitations of a Host for DNA Nanostructures.

    Science.gov (United States)

    Zhang, Bingru; Kitzerow, Heinz-S

    2016-03-31

    Lyotropic chromonic liquid crystals have recently been suggested for use as a self-organized host for dispersing and aligning self-organized DNA origami nanostructures. However, an appropriate pH value and a suitable cation concentration are necessary to stabilize such nanostructures and to avoid unfolding of the DNA. The present study shows that the nematic and columnar liquid crystal phases appearing in aqueous solutions of disodium cromoglycate are robust against the replacement of deionized water by a neutral or alkaline buffer solution. However, disodium cromoglycate precipitates when an acidic buffer is used or when the concentration of magnesium cations exceeds a critical concentration of about 0.6-0.7 mmol/L.

  20. Oral and transdermal drug delivery systems: role of lipid-based lyotropic liquid crystals

    OpenAIRE

    Rajabalaya, Rajan; Musa,Muhammad Nuh; Kifli, Nurolaini; Sheba R. David

    2017-01-01

    Rajan Rajabalaya, Muhammad Nuh Musa, Nurolaini Kifli, Sheba R David PAPRSB Institute of Health Sciences, Universiti Brunei Darussalam, Brunei Darussalam Abstract: Liquid crystal (LC) dosage forms, particularly those using lipid-based lyotropic LCs (LLCs), have generated considerable interest as potential drug delivery systems. LCs have the physical properties of liquids but retain some of the structural characteristics of crystalline solids. They are compatible with hydrophobic and hydrophi...

  1. Electrochemical and SEM properties of Co2+ ion in hexagonal mesophase of pluronic lyotropic liquid crystal template

    Indian Academy of Sciences (India)

    I S El-Hallag

    2009-10-01

    The electrochemical and SEM properties of Co2+ ion in hexagonal mesophase of the pluronic lyotropic liquid crystal template are reported. The cyclic voltammetric studies evidenced the occurrence of two slow electron transfer reduction processes. Such a reaction presumably related to the reduction of Co2+ ion to Co metal. The hexagonal (H1) lyotropic liquid crystalline phases of P84 surfactant have been used to template the electrochemical deposition of nanostructured cobalt films as well as its uses as background electrolyte. Electrochemical studies show that these films have very high surface areas, which reveals that the deposited film exhibits promising properties. The electrode parameters of Co(II) ion in hexagonal meso phase of the lyotropic liquid crystal ternary system (pluronic P84/cobalt/-xylene) is determined using cyclic voltammetry, deduced convolutive voltammetry and chronoamperometry techniques. The morphology of nanostructured deposited films of Co2+ ion in pluronic lyotropic liquid crystal template was investigated via scanning electron microscopy (SEM) technique.

  2. Selective Sequence for the Peptide-Triggered Phase Transition of Lyotropic Liquid-Crystalline Structures.

    Science.gov (United States)

    Liu, Qingtao; Dong, Yao-Da; Boyd, Ben J

    2016-05-24

    A novel concept of using mixed lipids to construct selective peptide-sequence-sensing lyotropic liquid-crystalline (LLC) dispersion systems was investigated. The LLC systems were constructed using a mixture of phytantriol, a lipid that forms lyotropic liquid-crystalline phases, and a novel synthesized peptide-lipid (peplipid) for sensing a target peptide with the RARAR sequence. The internal structure of the dispersed LLC particles was converted from the lamellar structure (liposomes) to the inverse bicontinuous cubic phase (cubosomes) in the presence of the target peptide. The addition of common human proteins did not induce any structural change, indicating a high selectivity of interaction with the target peptide. The concept has potential for the design of targeted controlled release drug delivery agents.

  3. Synthesis of Distinct Iron Oxide Nanomaterial Shapes Using Lyotropic Liquid Crystal Solvents

    Directory of Open Access Journals (Sweden)

    Seyyed Muhammad Salili

    2017-08-01

    Full Text Available A room temperature reduction-hydrolysis of Fe(III precursors such as FeCl3 or Fe(acac3 in various lyotropic liquid crystal phases (lamellar, hexagonal columnar, or micellar formed by a range of ionic or neutral surfactants in H2O is shown to be an effective and mild approach for the preparation of iron oxide (IO nanomaterials with several morphologies (shapes and dimensions, such as extended thin nanosheets with lateral dimensions of several hundred nanometers as well as smaller nanoflakes and nanodiscs in the tens of nanometers size regime. We will discuss the role of the used surfactants and lyotropic liquid crystal phases as well as the shape and size differences depending upon when and how the resulting nanomaterials were isolated from the reaction mixture. The presented synthetic methodology using lyotropic liquid crystal solvents should be widely applicable to several other transition metal oxides for which the described reduction-hydrolysis reaction sequence is a suitable pathway to obtain nanoscale particles.

  4. pH-responsive lyotropic liquid crystals for the preparation of pure cubic zirconia nanoparticles

    Science.gov (United States)

    He, Wei Yan; Liu, Jin Rong; He, Zhang; Cao, Zhen Zhu; Li, Cai Hong; Gao, Yan Fang

    2016-07-01

    We present a lyotropic liquid crystal system consisting of SDS/Triton X-100/water at 25 °C. This system is respond to pH variations with a phase switch. When pH is altered from alkaline (pH 13) to acidic (pH 2) conditions, phase change occurs from a bicontinuous hexagonal phase to a partially hexagonal phase until it disappears. The hexagonal phase under alkaline conditions is stable. Thus, this system is an ideal candidate for the preparation of pure cubic ZrO2 nanoparticles. XRD results confirm that the as-synthesized powder is composed of pure cubic ZrO2. These nanoparticles also exhibit a thermal stability of up to 800 °C. The size and morphological characteristics of the nanoparticles are greatly affected by ZrOCl2 concentration. The mechanism of zirconia nanoparticle synthesis in a lyotropic hexagonal phase was proposed.

  5. pH-responsive lyotropic liquid crystals for the preparation of pure cubic zirconia nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    He, Wei Yan; Liu, Jin Rong; He, Zhang; Cao, Zhen Zhu; Li, Cai Hong; Gao, Yan Fang [Inner Mongolia University of Technology, School of Chemical Engineering, Hohhot (China)

    2016-07-15

    We present a lyotropic liquid crystal system consisting of SDS/Triton X-100/water at 25 C. This system is respond to pH variations with a phase switch. When pH is altered from alkaline (pH 13) to acidic (pH 2) conditions, phase change occurs from a bicontinuous hexagonal phase to a partially hexagonal phase until it disappears. The hexagonal phase under alkaline conditions is stable. Thus, this system is an ideal candidate for the preparation of pure cubic ZrO{sub 2} nanoparticles. XRD results confirm that the as-synthesized powder is composed of pure cubic ZrO{sub 2}. These nanoparticles also exhibit a thermal stability of up to 800 C. The size and morphological characteristics of the nanoparticles are greatly affected by ZrOCl{sub 2} concentration. The mechanism of zirconia nanoparticle synthesis in a lyotropic hexagonal phase was proposed. (orig.)

  6. Preparation of Zirconia Nanoparticles with Different Morphology Using Lyotropic Liquid Crystal Template

    Directory of Open Access Journals (Sweden)

    HE Wei-yan

    2016-06-01

    Full Text Available Zirconia nanoparticles were prepared using ZrOCl2·8H2O and NH3·H2O as raw materials in the lyotropic hexagonal phase consisting of SDS/TritonX-100/H2O. Effects of pH on the phase structure stability of the template were determined. Effect of ZrOCl2 concentration on the size and morphology of zirconia were discussed. Polarizing optical microscopy was applied to investigate the stability of the hexagonal phase. The size and morphology of the nanoparticles were characterized by SEM, TEM and particle size analyzer. The crystalline structure and purity of the sample were characterized by XRD. In addition, the synthetic mechanism of zirconia nanoparticles in the lyotropic hexagonal phase were proposed by FT-IR. The results show that the hexagonal phase is stable in the condition of alkalinity and the hexagonal phase texture disappear in the conditions of acid; the size and morphology of the nanoparticles obtained are greatly affected by concentration of ZrOCl2. Morphology of samples changes from spherical-like particle to cotton-like particle with the increase of the concentration of ZrOCl2; the mechanism analysisresults show that complexation reaction between the precursor of the sample and the template does not occur, and crystal growth and nucleation of the zirconia nanoparticles are limited by a direct template route in the hexagonal phase lyotropic liquid crystal.

  7. Chromonic nematic phase and scalar order parameter of indanthrone derivative with ionic additives

    OpenAIRE

    Boiko O.P.; Vasyuta R.M.; Semenyshyn O.M.; Nastishin Yu.A.; Nazarenko V.G.

    2008-01-01

    We investigate influence of different ionic additives on the phase behaviour and scalar order parameter of lyotropic chromonic nematic liquid crystals formed by the molecules representing derivatives of indanthrone. KI, (NH4)2SO4 and NaCl salts increase biphasic nematic region on the temperature-concentration phase diagram, whereas the scalar orientational order parameter is hardly sensitive to their presence. We suggest that these changes are attributed to increase in the ag-gregate length a...

  8. Novel colloidal system: Magnetite-polymer particles/lyotropic liquid crystal under magnetic field

    Science.gov (United States)

    Mănăilă-Maximean, D.; Cîrtoaje, C.; Dănilă, O.; Donescu, D.

    2017-09-01

    We obtained a new highly ordered colloidal composite using specially manufactured magnetite-polymer nanoparticles and lyotropic liquid crystal. A good compatibility between the components was ensured by the functionalization of the particles during their synthesis. We studied the laser light transmission for the mixtures filled in sandwich-glass cells with homeotropic and planar treatment of the surfaces under external magnetic field. The Fréedericksz transition critical field was estimated, and its' behavior was compared to our new theoretical model based on the Brochard-de Gennes one.

  9. MECHANISM OF OPTICAL NONLINEARITY IN “LYOTROPIC LIQUID CRYSTAL — VIOLOGEN” SYSTEM

    Directory of Open Access Journals (Sweden)

    Hanna Bordyuh

    2014-06-01

    Full Text Available In the present work we analyze the characteristics of holographic grating recording and consider a mechanism of optical nonlinearity in the lyotropic liquid crystal (LLC — viologen samples. Taking into account structural and electrooptical properties of the admixture molecules it is possible to suggest that the recording is realized due to the change of polarizability of π-electron system of coloured viologen derivatives under the action of laser radiation. The main nonlinear optical parameters such as nonlinear refraction coefficient n2, cubic nonlinear susceptibility χ(3, and hyperpolarizability γ were calculated.

  10. Lyotropic hexagonal columnar liquid crystals of large colloidal gibbsite platelets

    NARCIS (Netherlands)

    Mourad, M.C.D.; Petukhov, A.V.; Vroege, G.J.; Lekkerkerker, H.N.W.

    2010-01-01

    We report the formation of hexagonal columnar liquid crystal phases in suspensions of large (570 nm diameter), sterically stabilized, colloidal gibbsite platelets in organic solvent. In thin cells these systems display strong iridescence originating from hexagonally arranged columns that are

  11. Hybrid silica luminescent materials based on lanthanide-containing lyotropic liquid crystal with polarized emission

    Energy Technology Data Exchange (ETDEWEB)

    Selivanova, N.M., E-mail: natsel@mail.ru [Kazan National Research Technological University, 68 Karl Marx Str., Kazan 420015 (Russian Federation); Vandyukov, A.E.; Gubaidullin, A.T. [A.E. Arbuzov Institute of Organic and Physical Chemistry of the Kazan Scientific Center of the Russian Academy of Sciences, 8 Acad. Arbuzov Str., Kazan 420088 (Russian Federation); Galyametdinov, Y.G. [Kazan National Research Technological University, 68 Karl Marx Str., Kazan 420015 (Russian Federation)

    2014-11-14

    This paper represents the template method for synthesis of hybrid silica films based on Ln-containing lyotropic liquid crystal and characterized by efficient luminescence. Luminescence films were prepared in situ by the sol–gel processes. Lyotropic liquid crystal (LLC) mesophases C{sub 12}H{sub 25}O(CH{sub 2}CH{sub 2}O){sub 10}H/Ln(NO{sub 3}){sub 3}·6H{sub 2}O/H{sub 2}O containing Ln (III) ions (Dy, Tb, Eu) were used as template. Polarized optical microscopy, X-ray powder diffraction, and FT-IR-spectroscopy were used for characterization of liquid crystal mesophases and hybrid films. The morphology of composite films was studied by the atomic force microscopy method (AFM). The optical properties of the resulting materials were evaluated. It was found that hybrid silica films demonstrate significant increase of their lifetime in comparison with an LLC system. New effects of linearly polarized emission revealed for Ln-containing hybrid silica films. Polarization in lanthanide-containing hybrid composites indicates that silica precursor causes orientation of emitting ions. - Highlights: • We suggest a new simple approach for creating luminescence hybrid silica films. • Ln-containing hybrid silica films demonstrate yellow, green and red emissions. • Tb(III)-containing hybrid film have a high lifetime. • We report effects of linearly polarized emission in hybrid film.

  12. Nonionic diethanolamide amphiphiles with isoprenoid-type hydrocarbon chains: thermotropic and lyotropic liquid crystalline phase behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Sagnella, Sharon M.; Conn, Charlotte E.; Krodkiewska, Irena; Drummond, Calum J. (CSIRO/MSE)

    2014-09-24

    The thermotropic and lyotropic liquid crystalline phase behaviour of a series of diethanolamide amphiphiles with isoprenoid-type hydrocarbon chains (geranoyl, H-farnesoyl, and phytanoyl) has been investigated. When neat, both H-farnesoyl and phytanoyl diethanolamide form a smectic liquid crystalline structure at sub-zero temperatures. In addition, all three diethanolamides exhibit a glass transition temperature at around -73 C. Geranoyl diethanolamide forms a lamellar crystalline phase with a lattice parameter of 17.4 {angstrom} following long term storage accompanied by the loss of the glass transition. In the presence of water, H-farnesoyl and phytanoyl diethanolamide form lyotropic liquid crystalline phases, whilst geranoyl diethanolamide forms an L{sub 2} phase. H-farnesoyl diethanolamide forms a fluid lamellar phase (L{sub {alpha}}) at room temperature and up to {approx} 40 C. Phytanoyl diethanolamide displays a rich mesomorphism forming the inverse diamond (Q{sub II}{sup D}) and gyroid (Q{sub II}{sup G}) bicontinuous cubic phases in addition to an L{sub {alpha}} phase.

  13. Chiral symmetry breaking by spatial confinement in tactoidal droplets of lyotropic chromonic liquid crystals.

    Science.gov (United States)

    Tortora, Luana; Lavrentovich, Oleg D

    2011-03-29

    In many colloidal systems, an orientationally ordered nematic (N) phase emerges from the isotropic (I) melt in the form of spindle-like birefringent tactoids. In cases studied so far, the tactoids always reveal a mirror-symmetric nonchiral structure, sometimes even when the building units are chiral. We report on chiral symmetry breaking in the nematic tactoids formed in molecularly nonchiral polymer-crowded aqueous solutions of low-molecular weight disodium cromoglycate. The parity is broken by twisted packing of self-assembled molecular aggregates within the tactoids as manifested by the observed optical activity. Fluorescent confocal microscopy reveals that the chiral N tactoids are located at the boundaries of cells. We explain the chirality induction as a replacement of energetically costly splay packing of the aggregates within the curved bipolar tactoidal shape with twisted packing. The effect represents a simple pathway of macroscopic chirality induction in an organic system with no molecular chirality, as the only requirements are orientational order and curved shape of confinement.

  14. Chiral symmetry breaking by spatial confinement in tactoidal droplets of lyotropic chromonic liquid crystals

    Science.gov (United States)

    Tortora, Luana; Lavrentovich, Oleg D.

    2011-01-01

    In many colloidal systems, an orientationally ordered nematic (N) phase emerges from the isotropic (I) melt in the form of spindle-like birefringent tactoids. In cases studied so far, the tactoids always reveal a mirror-symmetric nonchiral structure, sometimes even when the building units are chiral. We report on chiral symmetry breaking in the nematic tactoids formed in molecularly nonchiral polymer-crowded aqueous solutions of low-molecular weight disodium cromoglycate. The parity is broken by twisted packing of self-assembled molecular aggregates within the tactoids as manifested by the observed optical activity. Fluorescent confocal microscopy reveals that the chiral N tactoids are located at the boundaries of cells. We explain the chirality induction as a replacement of energetically costly splay packing of the aggregates within the curved bipolar tactoidal shape with twisted packing. The effect represents a simple pathway of macroscopic chirality induction in an organic system with no molecular chirality, as the only requirements are orientational order and curved shape of confinement. PMID:21402929

  15. Electrochemical studies of redox probes in self-organized lyotropic liquid crystalline systems

    Indian Academy of Sciences (India)

    P Suresh Kumar; V Lakshminarayanan

    2009-09-01

    Lyotropic liquid crystalline phases formed by surfactants are of special importance due to their close resemblance to biological systems. The redox reactions in such ordered media are of fundamental interest in understanding several complex processes occurring in the biological media, where the former can act as model systems. In this work, we have carried out the redox reactions of benzoquinone| hydroquinone, methyl viologen and ferrocenemethanol probes in a lyotropic hexagonal columnar phase (H1 phase) using cyclic voltammetry and electrochemical impedance spectroscopic studies. The liquid crystalline phase we have studied is made up of the non-ionic surfactant, Triton X-100 and water. Polarizing optical microscopic examination confirmed that the columnar hexagonal phase is retained even after the addition of redox probe as well as the supporting electrolyte. Our studies show a significant shift in the half-peak potentials of the redox probes in the H1 phase as compared to the solvent phase. The diffusion coefficient values for different redox probes in the H1 phase were also found to be significantly reduced when compared to the corresponding solvent media.

  16. Monodisperse nonionic isoprenoid-type hexahydrofarnesyl ethylene oxide surfactants: high throughput lyotropic liquid crystalline phase determination.

    Science.gov (United States)

    Fong, Celesta; Weerawardena, Asoka; Sagnella, Sharon M; Mulet, Xavier; Krodkiewska, Irena; Chong, Josephine; Drummond, Calum J

    2011-03-15

    The neat and lyotropic phase behavior of eight new ethylene oxide amphiphiles (EO = 1-8) with a hexahydrofarnesyl chain (3,7,11-trimethyldodecyl) and narrow polydispersity (>98.5% purity) is reported. Below five EO units the behavior of the neat surfactants show only a glass transition, Tg ∼ -90 °C. Above four EO units, crystallization (Tcrys) and crystal-isotropic liquid (Tm) transitions are also observed that increase with degree of ethoxylation of the surfactant headgroup. The lyotropic liquid crystalline phase behavior spans a complex spectrum of surfactant-water interfacial curvatures. Specifically, inverse phases are present below ambient temperatures for EO ethoxylation, with the crossover to normal phases occurring at HFarn(EO)(7-8) which exhibits normal hexagonal (H(I)) and cubic (Q(I)) phases at ambient temperatures. The toxicity of colloidal dispersions of these EO amphiphiles was assayed against normal breast epithelial (HMEpiC) and breast cancer (MCF7) cell lines. The IC50 of the EO amphiphiles was similar in both cell lines with moderate toxicity ranging from ca. <5 to 140 μM in an in vitro cell viability assay. Observations are qualitatively rationalized in terms of the molecular geometry of the surfactant. The physicochemical behavior of the HFarnesyl ethylene oxide amphiphiles is compared to other ethylene oxide surfactants.

  17. Enhanced thermal lens effect in gold nanoparticle-doped Lyotropic liquid crystal by nanoparticle clustering probed by Z-scan technique

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, S.L.; Lenart, V.M., E-mail: sgomez@uepg.br [Universidade Estadual de Ponta Grossa (UEPG), PR (Brazil). Dept. de Fisica; Turchiello, R.T. [Universidade Federal Tecnologica do Parana (UFTPR), Ponta Grossa, PR (Brazil). Dept. de Fisica; Goya, G.F. [Department of Condensed Matter Physics, Aragon Institute of Nanoscience, Zaragoza (Spain)

    2015-10-01

    This work presents an experimental study of the thermal lens effect in Au nanoparticles-doped lyotropic liquid crystals under cw 532 nm optical excitation. Spherical Au nanoparticles of about 12 nm were prepared by Turkevich’s method, and the lyotropic liquid crystal was a ternary mixture of SDS, 1-DeOH, and water that exhibits an isotropic phase at room temperature. The lyotropic matrix induces aggregation of the nanoparticles, leading to a broad and a red-shifted surface plasmon resonance. The thermal nonlinear optical refraction coefficient n{sub 2} increases as a power of number density of nanoparticles, being possible to address this behavior to nanoparticle clustering. (author)

  18. A Comprehensive Study on Lyotropic Liquid-Crystalline Behavior of an Amphiphile in 20 Kinds of Amino Acid Ionic Liquids.

    Science.gov (United States)

    Fujimura, Kanae; Ichikawa, Takahiro; Yoshio, Masafumi; Kato, Takashi; Ohno, Hiroyuki

    2016-02-18

    We examined the self-organization behavior of a designed amphiphilic molecule in 20 kinds of amino acid ionic liquids composed of 1-butyl-3-methylimidazolium cation and natural amino acid anion ([C4mim][AA]). Addition of [C4mim][AA], regardless of their anion species, to the amphiphile provided homogeneous mixtures showing lyotropic liquid-crystalline (LC) behavior. Upon increasing the component ratio of [C4mim][AA] in the mixtures, a successive change of the mesophase patterns from inverted hexagonal columnar, in some case via bicontinuous cubic, to layered phases was observed. By examining the LC properties at various temperatures and component ratios, we constructed lyotropic LC phase diagrams. Interestingly, the appearance of these phase diagrams is greatly different according to the selection of [AA]. Through comparison, we found that the self-organization behavior of an amphiphile in ionic liquids can be tuned by controlling their ability to form hydrogen-bond, van der Waals, and π-π interactions.

  19. Planar anchoring strength and pitch measurements in achiral and chiral chromonic liquid crystals using 90-degree twist cells

    Science.gov (United States)

    McGinn, Christine K.; Laderman, Laura I.; Zimmermann, Natalie; Kitzerow, Heinz-S.; Collings, Peter J.

    2013-12-01

    Chromonic liquid crystals are formed by molecules that spontaneously assemble into anisotropic structures in water. The ordering unit is therefore a molecular assembly instead of a molecule as in thermotropic liquid crystals. Although it has been known for a long time that certain dyes, drugs, and nucleic acids form chromonic liquid crystals, only recently has enough knowledge been gained on how to control their alignment so that studies of their fundamental liquid crystal properties can be performed. In this article, a simple method for producing planar alignment of the nematic phase in chromonic liquid crystals is described, and this in turn is used to create twisted nematic structures of both achiral and chiral chromonic liquid crystals. The optics of 90-degree twist cells allows the anchoring strength to be measured in achiral systems, which for this alignment technique is quite weak, about 3×10-7 J/m2 for both disodium cromoglycate and Sunset Yellow FCF. The addition of a chiral amino acid to the system causes the chiral nematic phase to form, and similar optical measurements in 90-degree twist cells produce a measurement of the intrinsic pitch of the chiral nematic phase. From these measurements, the helical twisting power for L-alanine is found to be (1.1±0.4)×10-2 μm-1 wt%-1 for 15 wt% disodium cromoglycate.

  20. The influence of dipalmitoyl phosphatidylserine on phase behaviour of and cellular response to lyotropic liquid crystalline dispersions.

    Science.gov (United States)

    Shen, Hsin-Hui; Crowston, Jonathan G; Huber, Florian; Saubern, Simon; McLean, Keith M; Hartley, Patrick G

    2010-12-01

    Lyotropic liquid crystalline nanoparticles (cubosomes) have the potential to act as amphiphilic scaffolds for the presentation of lipids and subsequent application in, for example, bioseparations and therapeutic delivery. In this work we have formulated lyotropic liquid crystalline systems based on the synthetic amphiphile 1,2,3-trihydroxy-3,7,11,15-tetramethylhexadecane (phytantriol) and containing the lipid dipalmitoyl phosphatidylserine (DPPS). We have prepared a range of DPPS-containing phytantriol cubosome formulations and characterized them using Small Angle X-ray Scattering and Cryo-transmission electron microscopy. These techniques show that increased DPPS content induces marked changes in lyotropic liquid crystalline phase behaviour, characterized by changes in crystallographic dimensions and increases in vesicle content. Furthermore, in vitro cell culture studies indicate that these changes correlate with lipid/surfactant cellular uptake and cytotoxicity. A model cell membrane based on a surface supported phospholipid bilayer was used to gain insights into cubosome-bilayer interactions using Quartz Crystal Microgravimetry. The data show that mass uptake at the supported bilayer increased with DPPS content. We propose that the cytotoxicity of the DPPS-containing dispersions results from changes in lipid/surfactant phase behaviour and the preferential attachment and fusion of vesicles at the cell membrane.

  1. Annihilation dynamics of stringlike topological defects in a nematic lyotropic liquid crystal.

    Science.gov (United States)

    Guimarães, R R; Mendes, R S; Fernandes, P R G; Mukai, H

    2013-10-09

    Topological defects can appear whenever there is some type of ordering. Its ubiquity in nature has been the subject of several studies, from early Universe to condensed matter. In this work, we investigated the annihilation dynamics of defects and antidefects in a lyotropic nematic liquid crystal (ternary mixture of potassium laurate, decanol and deionized-destillated water) using the polarized optical light microscopy technique. We analyzed Schlieren textures with topological defects produced due to a symmetry breaking in the transition of the isotropic to nematic calamitic phase after a temperature quench. As result, we obtained for the distance D between two annihilating defects (defect-antidefect pair), as a function of time t remaining for the annihilation, the scaling law D ∝ t(α), with α = 0.390 and standard deviation σ = 0.085. Our findings go in the direction to extend experimental results related to dynamics of defects in liquid crystals since only thermotropic and polymerics ones had been investigated. In addition, our results are in good quantitative agreement with previous investigations on the subject.

  2. Line Tension of Twist-Free Carbon Nanotube Lyotropic Liquid Crystal Microdroplets on Solid Surfaces.

    Science.gov (United States)

    Jamali, Vida; Biggers, Evan G; van der Schoot, Paul; Pasquali, Matteo

    2017-09-12

    Line tension, i.e., the force on a three-phase contact line, has been a subject of extensive research due to its impact on technological applications including nanolithography and nanofluidics. However, there is no consensus on the sign and magnitude of the line tension, mainly because it only affects the shape of small droplets, below the length scale dictated by the ratio of line tension to surface tension σ/τ. This ratio is related to the size of constitutive molecules in the system, which translates to a nanometer for conventional fluids. Here, we show that this ratio is orders of magnitude larger in lyotropic liquid crystal systems comprising micrometer-long colloidal particles. Such systems are known to form spindle-shaped elongated liquid crystal droplets in coexistence with the isotropic phase, with the droplets flattening when in contact with flat solid surfaces. We propose a method to characterize the line tension by fitting measured droplet shape to a macroscopic theoretical model that incorporates interfacial forces and elastic deformation of the nematic phase. By applying this method to hundreds of droplets of carbon nanotubes dissolved in chlorosulfonic acid, we find that σ/τ ∼ -0.84 ± 0.06 μm. This ratio is 2 orders of magnitude larger than what has been reported for conventional fluids, in agreement with theoretical scaling arguments.

  3. Oral and transdermal drug delivery systems: role of lipid-based lyotropic liquid crystals.

    Science.gov (United States)

    Rajabalaya, Rajan; Musa, Muhammad Nuh; Kifli, Nurolaini; David, Sheba R

    2017-01-01

    Liquid crystal (LC) dosage forms, particularly those using lipid-based lyotropic LCs (LLCs), have generated considerable interest as potential drug delivery systems. LCs have the physical properties of liquids but retain some of the structural characteristics of crystalline solids. They are compatible with hydrophobic and hydrophilic compounds of many different classes and can protect even biologicals and nucleic acids from degradation. This review, focused on research conducted over the past 5 years, discusses the structural evaluation of LCs and their effects in drug formulations. The structural classification of LLCs into lamellar, hexagonal and micellar cubic phases is described. The structures of these phases are influenced by the addition of surfactants, which include a variety of nontoxic, biodegradable lipids; these also enhance drug solubility. LLC structure influences drug localization, particle size and viscosity, which, in turn, determine drug delivery properties. Through several specific examples, we describe the applications of LLCs in oral and topical drug formulations, the latter including transdermal and ocular delivery. In oral LLC formulations, micelle compositions and the resulting LLC structures can determine drug solubilization and stability as well as intestinal transport and absorption. Similarly, in topical LLC formulations, composition can influence whether the drug is retained in the skin or delivered transdermally. Owing to their enhancement of drug stability and promotion of controlled drug delivery, LLCs are becoming increasingly popular in pharmaceutical formulations.

  4. Oral and transdermal drug delivery systems: role of lipid-based lyotropic liquid crystals

    Science.gov (United States)

    Rajabalaya, Rajan; Musa, Muhammad Nuh; Kifli, Nurolaini; David, Sheba R

    2017-01-01

    Liquid crystal (LC) dosage forms, particularly those using lipid-based lyotropic LCs (LLCs), have generated considerable interest as potential drug delivery systems. LCs have the physical properties of liquids but retain some of the structural characteristics of crystalline solids. They are compatible with hydrophobic and hydrophilic compounds of many different classes and can protect even biologicals and nucleic acids from degradation. This review, focused on research conducted over the past 5 years, discusses the structural evaluation of LCs and their effects in drug formulations. The structural classification of LLCs into lamellar, hexagonal and micellar cubic phases is described. The structures of these phases are influenced by the addition of surfactants, which include a variety of nontoxic, biodegradable lipids; these also enhance drug solubility. LLC structure influences drug localization, particle size and viscosity, which, in turn, determine drug delivery properties. Through several specific examples, we describe the applications of LLCs in oral and topical drug formulations, the latter including transdermal and ocular delivery. In oral LLC formulations, micelle compositions and the resulting LLC structures can determine drug solubilization and stability as well as intestinal transport and absorption. Similarly, in topical LLC formulations, composition can influence whether the drug is retained in the skin or delivered transdermally. Owing to their enhancement of drug stability and promotion of controlled drug delivery, LLCs are becoming increasingly popular in pharmaceutical formulations. PMID:28243062

  5. Gels and lyotropic liquid crystals: using an imidazolium-based catanionic surfactant in binary solvents.

    Science.gov (United States)

    Cheng, Ni; Hu, Qiongzheng; Bi, Yanhui; Xu, Wenwen; Gong, Yanjun; Yu, Li

    2014-08-01

    The self-assembly behavior of an imidazolium-based catanionic surfactant, 1-butyl-3-methylimidazolium dodecylsulfate ([C4mim][C12H25SO4]), was investigated in water-ethylammonium nitrate (EAN) mixed solvents with different volume ratios. It is particular interesting that this simple surfactant could not only form lyotropic liquid crystals (LLC) with multimesophases, i.e., normal hexagonal (H1), lamellar liquid crystal (Lα), and reverse bicontinuous cubic phase (V2), in the water-rich environment but also act as an efficient low-molecular-weight gelator (LMWG) which gelated EAN-abundant binary media in a broad concentration range. The peculiar nanodisk cluster morphology of gels composed of similar bilayer units was first observed. FT-IR spectra and density functional theory (DFT) calculations reveal that strong H bonding and electrostatic interactions between EAN and the headgroups of [C4mim][C12H25SO4] are primarily responsible for gelation. The self-assembled gels displayed excellent mechanical strength and a thermoreversible sol-gel transition. It is for the first time that a rich variety of controllable ordered aggregates could be observed only by simply modulating the concentration of a single imidazolium-based catanionic surfactant or the ratio of mixed solvents. This environmentally friendly system is expected to have broad applications in various fields, such as materials science, drug delivery systems, and supramolecular chemistry.

  6. New nanotechnology for the guided tissue regeneration of skin--potential of lyotropic liquid crystals.

    Science.gov (United States)

    Yamaguchi, Y; Nagasawa, T; Kitagawa, A; Nakamura, N; Matsumoto, K; Uchiwa, H; Hirata, K; Igarashi, R

    2006-02-01

    Tissue in body must quickly recognize injury to response to the rapid pace of epidermal growth. In skin, the epidermal cells must also react to danger signals from the surrounding extracellular lipid of the stratum corneum spaces and immediately participate by initiating the wound repair process. The topical administration of the lyotropic liquid crystal nanocube to stratum corneum rapidly broke down the lipid lamella structure which would be recognized as a wound without organ-change. This can activate a variety of biological processes. This study set out to determine whether the phase transition of the lipid to a neighbouring different physicochemical structure can stimulate keratinocyte cells and what mechanism is responsible for this response. Using small angle x-ray scattering (SAXS) analysis, a response to the transient structural change of lipid was detected which might result from the diffusion of oil and/or water from nanocube liquid crystal towards the lipid lamella phase. Simultaneously, a significant increase in growth factors and inflammatory cytokines was detected after administration of nanocube. Not only the excess expression of cytokines but also the extent of TEWL as a barrier marker of skin increased. These observations suggest that a structural change in lipid can stimulate and trigger recognition of a slight injury in the wound defence and a repair response as homeostasis. This method actually succeeded in improving photo-induced hyperpigmentation on a human face.

  7. Thermotropic and lyotropic behaviour of new liquid-crystalline materials with different hydrophilic groups: synthesis and mesomorphic properties

    Directory of Open Access Journals (Sweden)

    Alexej Bubnov

    2013-02-01

    Full Text Available Several new calamitic liquid-crystalline (LC materials with flexible hydrophilic chains, namely either hydroxy groups or ethylene glycol units, or both types together, have been synthesized in order to look for new functional LC materials exhibiting both, thermotropic and lyotropic behaviour. Such materials are of high potential interest for challenging issues such as the self-organization of carbon nanotubes or various nanoparticles. Thermotropic mesomorphic properties have been studied by using polarizing optical microscopy, differential scanning calorimetry and X-ray scattering. Four of these nonchiral and chiral materials exhibit nematic and chiral nematic phases, respectively. For some molecular structures, smectic phases have also been detected. A contact sample of one of the prepared compounds with diethylene glycol clearly shows the lyotropic behaviour; namely a lamellar phase was observed. The relationship between the molecular structure and mesomorphic properties of these new LCs with hydrophilic chains is discussed.

  8. Thermotropic and lyotropic behaviour of new liquid-crystalline materials with different hydrophilic groups: synthesis and mesomorphic properties.

    Science.gov (United States)

    Bubnov, Alexej; Kašpar, Miroslav; Hamplová, Věra; Dawin, Ute; Giesselmann, Frank

    2013-01-01

    Several new calamitic liquid-crystalline (LC) materials with flexible hydrophilic chains, namely either hydroxy groups or ethylene glycol units, or both types together, have been synthesized in order to look for new functional LC materials exhibiting both, thermotropic and lyotropic behaviour. Such materials are of high potential interest for challenging issues such as the self-organization of carbon nanotubes or various nanoparticles. Thermotropic mesomorphic properties have been studied by using polarizing optical microscopy, differential scanning calorimetry and X-ray scattering. Four of these nonchiral and chiral materials exhibit nematic and chiral nematic phases, respectively. For some molecular structures, smectic phases have also been detected. A contact sample of one of the prepared compounds with diethylene glycol clearly shows the lyotropic behaviour; namely a lamellar phase was observed. The relationship between the molecular structure and mesomorphic properties of these new LCs with hydrophilic chains is discussed.

  9. Orientations of Chromonic Liquid Crystals by Imprinted or Rubbed Polymer Films

    Science.gov (United States)

    Yi, Youngwoo; McGuire, Aya; Clark, Noel

    2014-03-01

    A variety of novel alignment effects of chromonic liquid crystal phases of sunset yellow (SSY)/water, disodium cromoglycate (DSCG)/water, and their mixtures by thiol-ene polymer films topographically imprinted with linear channels are observed using polarizing optical microscopy. Nematic DSCG and SSY at low concentration and their nematic mixtures orient with the long axes of stacked chromonic aggregates on average parallel to the channels, that is, with the molecular planes normal to the channel axis. On the contrary, nematic SSY in contact with the rubbed polyimide films orients with the long axes on average in-plane perpendicular to the rubbing direction, arguably, due to a tongue-groove interaction between SSY and the stretched PI chains. Furthermore, multi-stable alignments are observed in SSY solutions of sufficiently high concentration, including preferential in-plane orientation of the long axes of the aggregates parallel to, perpendicular to, and 45° rotated from the channels. This work was supported by NSF grant DMR 1207606, NSF MRSEC grant DMR 0820579, and NSF Research Experience for Undergraduate programs.

  10. Triply Periodic Multiply Continuous Lyotropic Liquid Crystals Derived from Gemini Surfactants

    Science.gov (United States)

    Sorenson, Gregory P.

    A subtle balance of non-covalent interactions directs the self-assembly of small molecule amphiphiles in aqueous media into supramolecular assemblies known as aqueous lyotropic liquid crystals (LLCs). Aqueous LLCs form many intricate, ordered nanoscale morphologies comprising distinct and structurally periodic hydrophobic and hydrophilic domains. Triply periodic multiply continuous (TPMC) LLC morphologies, which exhibit continuous hydrophobic and aqueous domains that percolate in three-dimensions, are of particular interest by virtue of their potentially wide ranging technological applications including advanced membranes for electrical energy storage and utilization, therapeutic delivery, and templates for new organic and inorganic mesoporous materials. However, robust molecular design criteria for amphiphiles that readily form TMPC morphologies are notably lacking in the literature. Recent reports have described the increased propensity for quaternary ammonium and phosphonium gemini surfactants, derived from dimerization of traditional single-tail surfactants at or near the hydrophilic headgroups through a hydrophobic linker, to stabilize TMPC mesophases. The generality of this surfactant design strategy remains untested in other amphiphiles classes bearing different headgroup chemistries. In this thesis, we describe the unusual aqueous LLC phase behavior of series of gemini dicarboxylate amphiphiles as a function of the alkyl tail length, hydrophobic linker length, and the charge-compensating counterion. These dicarboxylate surfactants unexpectedly exhibit a strong propensity to form TPMC LLCs over amphiphile concentration windows as wide as 20 wt% over a temperature range T = 25--100 °C. Through systematic modifications of the length of the hydrophobic linker and alkyl tails, we use small-angle X-ray scattering to demonstrate that these surfactants adopt new LLC mesophases including the first report of a single-gyroid phase (I4132 symmetry) and a new

  11. Phase behavior of chromonic liquid crystal mixtures of Sunset Yellow and Disodium Cromoglycate

    Science.gov (United States)

    Yamaguchi, Akihiro; Smith, Gregory; Yi, Youngwoo; Xu, Charles; Biffi, Silvia; Serra, Francesca; Bellini, Tommaso; Clark, Noel

    2014-03-01

    Chromonic liquid crystals (CLCs) are formed when planar molecules dissolved in water stack into rod-like aggregates that can order as liquid crystals. Isotropic, nematic, and M-phases can be observed depending on the degree of molecular orientational and positional order by variation of the CLC concentration. We focused on mixtures of two well-known CLCs, Sunset Yellow, a food dye, and disodium cromoglycate (DSCG), an asthma medication. In order to study the phase behaviors of these mixtures, we observed their textures in glass cells and capillaries using polarized light microscopy. We report here a ternary phase diagram describing the complete phase behavior of the CLC mixtures. We observed a variety of phase behaviors depending on species ratio and concentration. In the isotropic phase, no clear phase separation of the two dyes was observed, while separation did occur in many nematic and M-phase combinations. We will also describe phase observations made using a light spectroscopy and bulk centrifugal partitioning. Grant support: NSF DMR 1207606 and NSF MRSEC DMR-0820579.

  12. Radiolytic syntheses of hollow UO{sub 2} nanospheres in Triton X-100-based lyotropic liquid crystals

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yongming; Chen, Qingde; Shen, Xinghai [Peking Univ., Beijing (China). Fundamental Science on Radiochemistry and Radiation Chemistry Lab.

    2017-08-01

    Hollow nanospheres (φ: 60-80 nm, wall thickness: 10-20 nm), consisted of UO{sub 2} nanoparticles (φ: 3-5 nm), were successfully prepared in a Triton X-100-water (50:50, w/w) hexagonal lyotropic liquid crystal (LLC) by γ-irradiation, where water soluble ammonium uranyl tricarbonate was added as precursor. The product was stable at least up to 300 C. Furthermore, whether the nanospheres were hollow or not, and the wall thickness of the hollow nanospheres could be easily controlled via adjusting dose rate. While in the Triton X-100 based micellar systems, only solid nanospheres were obtained. At last, a possible combination mechanism containing adsorption, aggregation and fracturing processes was proposed.

  13. Multi-scale characterization of lyotropic liquid crystals using 2H and diffusion MRI with spatial resolution in three dimensions.

    Directory of Open Access Journals (Sweden)

    Diana Bernin

    Full Text Available The ability of lyotropic liquid crystals to form intricate structures on a range of length scales can be utilized for the synthesis of structurally complex inorganic materials, as well as in devices for controlled drug delivery. Here we employ magnetic resonance imaging (MRI for non-invasive characterization of nano-, micro-, and millimeter scale structures in liquid crystals. The structure is mirrored in the translational and rotational motion of the water, which we assess by measuring spatially resolved self-diffusion tensors and 2H spectra. Our approach differs from previous works in that the MRI parameters are mapped with spatial resolution in all three dimensions, thus allowing for detailed studies of liquid crystals with complex millimeter-scale morphologies that are stable on the measurement time-scale of 10 hours. The 2H data conveys information on the nanometer-scale structure of the liquid crystalline phase, while the combination of diffusion and 2H data permits an estimate of the orientational distribution of micrometer-scale anisotropic domains. We study lamellar phases consisting of the nonionic surfactant C10E3 in 2H2O, and follow their structural equilibration after a temperature jump and the cessation of shear. Our experimental approach may be useful for detailed characterization of liquid crystalline materials with structures on multiple length scales, as well as for studying the mechanisms of phase transitions.

  14. Electrolyte effects on the chiral induction and on its temperature dependence in a chiral nematic lyotropic liquid crystal.

    Science.gov (United States)

    Dawin, Ute C; Osipov, Mikhail A; Giesselmann, Frank

    2010-08-19

    We present a study on the effect of added CsCl and of temperature variation on the chiral induction in a chiral nematic lyotropic liquid crystal (LC) composed of the surfactant cesium perfluorooctanoate (CsPFO), water, and the chiral dopant d-Leucine (d-Leu). The chiral induction was measured as the helical pitch P. The role of the additives CsCl and d-Leu on the phase behavior is investigated and discussed. The thermal stabilization effect of CsCl is shown to lead to an apparent salt effect on the pitch when the pitch is compared at a constant temperature. This apparent effect is removed by comparing the pitch measured for different salt concentrations at a temperature relative to the phase-transition temperatures; thus, the real salt effect on the pitch is described. High salt concentrations are shown to increase the pitch, that is, hinder the chiral induction. The effect is discussed in terms of a decreased solubilization of the amphiphilic chiral solute d-Leu in the micelles due to the salt-induced screening of the surfactant head groups and the consequential denser packing of the surfactants. The temperature variation of the pitch is investigated for all CsCl concentrations and is found to be essentially independent of the salt concentration. The temperature variation is analyzed and discussed in the context of a theoretical model taking into account specific properties of lyotropic liquid crystals. A hyperbolic decrease of the pitch is found with increasing temperature, which is known, from thermotropic liquid crystals, to stem from pretransitional critical fluctuations close to the lamellar phase. However, the experimental data confirmed the theoretical prediction that, at high temperature, that is, far away from the transition into the lamellar phase, the pitch is characterized by a linear temperature dependence which is determined by a combination of steric and dispersion chiral interactions. The parameters of the theoretical expression for the pitch have

  15. Domed Silica Microcylinders Coated with Oleophilic Polypeptides and Their Behavior in Lyotropic Cholesteric Liquid Crystals of the Same Polypeptide.

    Science.gov (United States)

    Rosu, Cornelia; Jacobeen, Shane; Park, Katherine; Reichmanis, Elsa; Yunker, Peter; Russo, Paul S

    2016-12-13

    Liquid crystals can organize dispersed particles into useful and exotic structures. In the case of lyotropic cholesteric polypeptide liquid crystals, polypeptide-coated particles are appealing because the surface chemistry matches that of the polymeric mesogen, which permits a tighter focus on factors such as extended particle shape. The colloidal particles developed here consist of a magnetic and fluorescent cylindrically symmetric silica core with one rounded, almost hemispherical end. Functionalized with helical poly(γ-stearyl-l-glutamate) (PSLG), the particles were dispersed at different concentrations in cholesteric liquid crystals (ChLC) of the same polymer in tetrahydrofuran (THF). Defects introduced by the particles to the director field of the bulk PSLG/THF host led to a variety of phases. In fresh mixtures, the cholesteric mesophase of the PSLG matrix was distorted, as reflected in the absence of the characteristic fingerprint pattern. Over time, the fingerprint pattern returned, more quickly when the concentration of the PSLG-coated particles was low. At low particle concentration the particles were "guided" by the PSLG liquid crystal to organize into patterns similar to that of the re-formed bulk chiral nematic phase. When their concentration increased, the well-dispersed PSLG-coated particles seemed to map onto the distortions in the bulk host's local director field. The particles located near the glass vial-ChLC interfaces were stacked lengthwise into architectures with apparent two-dimensional hexagonal symmetry. The size of these "crystalline" structures increased with particle concentration. They displayed remarkable stability toward an external magnetic field; hydrophobic interactions between the PSLG polymers in the shell and those in the bulk LC matrix may be responsible. The results show that bio-inspired LCs can assemble suitable colloidal particles into soft crystalline structures.

  16. Biomimetic Nucleation and Morphology Control of CaCO_3 in PAAm Hydrogels Synthesized from Lyotropic Liquid Crystalline Templates

    Institute of Scientific and Technical Information of China (English)

    DU, Zhuwei; LU, Cuixiang; LI, Haoran; LI, Dingjie

    2009-01-01

    Hydrogels have been thought to be the material which can provide appealing replacements of biological organisms. Pores of hydrogeis synthesized from lyotropic liquid crystalline (LLC) templates were smaller in size and more uniform than those of traditional hydrogels. LLC poly-acrylamide (PAAm) hydrogels were used as the growth media of CaCO_3. After copolymerized with acrylic acid and 2-acrylamido-2-methylpropanesulfonic acid (AMPS),LLC hydrogels were modified with COOH and SO_3H, respectively. The effect of functional groups on the biomitactic mineralization of CaCO_3 was studied. Most of crystals from traditional hydrogels are rhombohedral and could not form aggregates. Only a few could aggregate and have a particular morphology with irregular orientation of subcrystal. Compared with crystals separated from traditional hydrogels, crystals growing in the LLC hydrogels were much more regulated and could form aggregates with particular morphology and regular orientation, that is,face (104) of rhombohedral subcrystals parallel to the surface of the macrocrystals. Modification of COOH and SO_3H groups made CaCO_3 subcrystal align more tightly. COOH had minor influences on the crystal orientation and small modification to the aggregate morphology. SO_3H groups could change the crystal orientation and morphology effectively. The aggregates are pseudo-spherical and the face perpendicularity to the face (104) parallels to the surface of the aggregates.

  17. Disposition and association of the steric stabilizer Pluronic® F127 in lyotropic liquid crystalline nanostructured particle dispersions.

    Science.gov (United States)

    Tilley, Adam J; Drummond, Calum J; Boyd, Ben J

    2013-02-15

    Liquid crystalline nanostructured particles, such as cubosomes and hexosomes, are most often colloidally stabilised using the tri-block co-polymer Pluronic® F127. Although the effect of F127 on the internal particle nanostructure has been well studied, the associative aspects of F127 with cubosomes and hexosomes are poorly understood. In this study the quantitative association of F127 with phytantriol-based cubosomes and hexosomes was investigated. The amount of free F127 in the dispersions was determined using pressure ultra-filtration. The percentage of F127 associated with the particles plateaued with increasing F127 concentration above the critical aggregation concentration. Hence the free concentration of F127 in the dispersion medium was proposed as a key factor governing association below the CMC, and partitioning of F127 between micelles and particles occurred above the CMC. The association of F127 with the particles was irreversible on dilution. The F127 associated with both the external and internal surfaces of the phytantriol cubosomes. The effects of lipid and F127 concentration, lipid type, dilution of the dispersions and internal nanostructure were also elucidated. A greater amount of F127 was associated with cubosomes comprised of glyceryl monooleate (GMO) than those prepared using phytantriol. Hexosomes prepared using a mixture of phytantriol and vitamin E acetate (vitEA) had a greater amount of F127 associated with them than phytantriol cubosomes. Hexosomes prepared using selachyl alcohol had less F127 associated with them than phytantriol:vitEA-based hexosomes and GMO-based cubosomes. This indicated that both the lipid from which the particles are composed and the particle internal nanostructure have an influence on the association of F127 with lyotropic liquid crystalline nanostructured particles. Copyright © 2012 Elsevier Inc. All rights reserved.

  18. Topological Influence of Lyotropic Liquid Crystalline Systems on Excited-State Proton Transfer Dynamics.

    Science.gov (United States)

    Roy, Bibhisan; Satpathi, Sagar; Hazra, Partha

    2016-03-29

    In the present work, we have investigated the excited-state proton transfer (ESPT) dynamics inside lipid-based reverse hexagonal (HII), gyroid Ia3d, and diamond Pn3m LLC phases. Polarized light microscopy (PLM) and small-angle X-ray scattering (SAXS) techniques have been employed for the characterization of LLC systems. Time-resolved fluorescence results reveal the retarded ESPT dynamics inside liquid crystalline systems compared to bulk water, and it follows the order HII water and it follows the order H2O constant and different channel diameters of these LLC systems. However, the dissociation dynamics is found to be slower than bulk water and it follows the order HII dissociation dynamics in these liquid crystalline systems.

  19. Shear rheology and in-vitro release kinetic study of apigenin from lyotropic liquid crystal.

    Science.gov (United States)

    Fan, Jun; Liu, Feng; Wang, Zhongni

    2016-01-30

    Apigenin is a flavonoid compound with diverse pharmacological functions which could develop health benefit products, but its formulation is hampered by its poor water solubility and bioavailability. In this paper, in order to overcome these difficulties, apigenin was encapsulated in LLC formed by polyoxyethylene-10-oleyl ether (Brij 97) and sodium deoxycholate (NaDC) mixtures. The hexagonal liquid crystalline phase (H) and the cubic liquid crystalline phase (C) were found in this system. The shear rheology was used to study the structure change with temperature. It was shown that C3 (Brij 97-NaDC/IPM-PEG400/H2O=36:9:55) was C at low temperature. But above 35.6°C, the matrix of C3 completely transformed to polymer solution. The matrix of H3 was H (Brij 97-NaDC:IPM-PEG 400:H2O=50:9:41) below 50°C, but the structural strength change was obvious. Vitro release experiment was used to study drug release kinetics. It was indicated that apigenin encapsulated in LLC conformed to the concentration diffusion model, and cumulative percentage of apigenin released from C3 and H3 had corresponding relationship with the shear rheology at different temperatures. Copyright © 2015. Published by Elsevier B.V.

  20. Cellulose Acetate Sulfate as a Lyotropic Liquid Crystalline Polyelectrolyte: Synthesis, Properties, and Application

    Directory of Open Access Journals (Sweden)

    D. D. Grinshpan

    2010-01-01

    Full Text Available The optimal conditions of cellulose acetate sulfate (CAS homogeneous synthesis with the yield of 94–98 wt.% have been determined. CAS was confirmed to have an even distribution of functional groups along the polymer chain. The polymer was characterized by an exceptionally high water solubility (up to 70 wt.%. The isothermal diagrams of its solubility in water-alcohol media have been obtained. CAS aqueous solutions stability, electrolytic, thermal, and viscous properties have been defined. The main hydrodynamic characteristics such as intrinsic viscosity, Huggins constant, and crossover concentration have been evaluated. The parameters of polymer chain thermodynamic rigidity have been calculated. The formation of liquid crystalline structures in concentrated CAS solutions has been confirmed. CAS was recommended to be used as a binder for the medicinal forms of activated carbon and carbon sorbent for water treatment, hydrophilic ointment foundation.

  1. Nonionic amphiphile nanoarchitectonics: self-assembly into micelles and lyotropic liquid crystals

    Science.gov (United States)

    Shrestha, Lok Kumar; Strzelczyk, Karolina Maria; Goswami Shrestha, Rekha; Ichikawa, Kotoko; Aramaki, Kenji; Hill, Jonathan P.; Ariga, Katsuhiko

    2015-05-01

    Amphiphiles, molecules that possess both hydrophilic and hydrophobic moieties, are architecturally simple molecules that can spontaneously self-assemble into complex hierarchical structures from lower to higher dimensions either in the bulk phase or at an interface. Recent developments in multifunctional nanostructure design using the advanced concept of nanoarchitectonics utilize this simple process of assembly. Amphiphilic self-assemblies involving lipids or proteins mimic the structure of biological systems, thus highlighting the necessity of a fundamental physical understanding of amphiphilic self-assembly towards a realization of the complex mechanisms operating in nature. Herein, we describe self-assembled microstructures of biocompatible and biodegradable tetraglycerol lauryl ether (C12G4) nonionic surfactant in an aqueous solvent system. Temperature-composition analyses of equilibrium phases identified by using small-angle x-ray scattering (SAXS) provide strong evidence of various spontaneously self-assembled mesostructures, such as normal micelles (Wm), hexagonal liquid crystal (H1), and reverse micelles (Om). In contrast to conventional poly(oxyethylene) nonionic surfactants, C12G4 did not exhibit the clouding phenomenon at higher temperatures (phase separation was not observed up to 100 °C), demonstrating the greater thermal stability of the self-assembled mesophases. Generalized indirect Fourier transformation (GIFT) evaluation of the SAXS data confirmed the formation of core-shell-type spherical micelles with a maximum dimension ca. 8.7 nm. The shape and size of the C12G4 micelles remained apparently unchanged over a wide range of concentrations (up to 20%), but intermicellar interactions increased and could be described by the Percus-Yevick (PY) theory (after Carnahan and Starling), which provides a very accurate analytical expression for the osmotic pressure of a monodisperse hard sphere.

  2. Solvation Dynamics in Different Phases of the Lyotropic Liquid Crystalline System.

    Science.gov (United States)

    Roy, Bibhisan; Satpathi, Sagar; Gavvala, Krishna; Koninti, Raj Kumar; Hazra, Partha

    2015-09-03

    Reverse hexagonal (HII) liquid crystalline material based on glycerol monooleate (GMO) is considered as a potential carrier for drugs and other important biomolecules due to its thermotropic phase change and excellent morphology. In this work, the dynamics of encapsulated water, which plays important role in stabilization and formation of reverse hexagonal mesophase, has been investigated by time dependent Stokes shift method using Coumarin-343 as a solvation probe. The formation of the reverse hexagonal mesophase (HII) and transformation to the L2 phase have been monitored using small-angle X-ray scattering and polarized light microscopy experiments. REES studies suggest the existence of different polar regions in both HII and L2 systems. The solvation dynamics study inside the reverse hexagonal (HII) phase reveals the existence of two different types of water molecules exhibiting dynamics on a 120-900 ps time scale. The estimated diffusion coefficients of both types of water molecules obtained from the observed dynamics are in good agreement with the measured diffusion coefficient collected from the NMR study. The calculated activation energy is found to be 2.05 kcal/mol, which is associated with coupled rotational-translational water relaxation dynamics upon the transition from "bound" to "quasi-free" state. The observed ∼2 ns faster dynamics of the L2 phase compared to the HII phase may be associated with both the phase transformation as well as thermotropic effect on the relaxation process. Microviscosities calculated from time-resolved anisotropy studies infer that the interface is almost ∼22 times higher viscous than the central part of the cylinder. Overall, our results reveal the unique dynamical features of water inside the cylinder of reverse hexagonal and inverse micellar phases.

  3. Prediction of EPR Spectra of Lyotropic Liquid Crystals using a Combination of Molecular Dynamics Simulations and the Model-Free Approach.

    Science.gov (United States)

    Prior, Christopher; Oganesyan, Vasily S

    2017-09-21

    We report the first application of fully atomistic molecular dynamics (MD) simulations to the prediction of the motional electron paramagnetic resonance (EPR) spectra of lyotropic liquid crystals in different aggregation states doped with a paramagnetic spin probe. The purpose of this study is twofold. First, given that EPR spectra are highly sensitive to the motions and order of the spin probes doped within lyotropic aggregates, simulation of EPR line shapes from the results of MD modelling provides an ultimate test bed for the force fields currently employed to model such systems. Second, the EPR line shapes are simulated using the motional parameters extracted from MD trajectories using the Model-Free (MF) approach. Thus a combined MD-EPR methodology allowed us to test directly the validity of the application of the MF approach to systems with multi-component molecular motions. All-atom MD simulations using the General AMBER Force Field (GAFF) have been performed on sodium dodecyl sulfate (SDS) and dodecyltrimethylammonium chloride (DTAC) liquid crystals. The resulting MD trajectories were used to predict and interpret the EPR spectra of pre-micellar, micellar, rod and lamellar aggregates. The predicted EPR spectra demonstrate good agreement with most of experimental line shapes thus confirming the validity of both the force fields employed and the MF approach for the studied systems. At the same time simulation results confirm that GAFF tends to overestimate the packing and the order of the carbonyl chains of the surfactant molecules. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Emulsion of aqueous-based nonspherical droplets in aqueous solutions by single-chain surfactants: templated assembly by nonamphiphilic lyotropic liquid crystals in water.

    Science.gov (United States)

    Varghese, Nisha; Shetye, Gauri S; Bandyopadhyay, Debjyoti; Gobalasingham, Nemal; Seo, JinAm; Wang, Jo-Han; Theiler, Barbara; Luk, Yan-Yeung

    2012-07-24

    Single-chain surfactants usually emulsify and stabilize oily substances into droplets in an aqueous solution. Here, we report a coassembly system, in which single types of anionic or non-ionic surfactants emulsify a class of water-soluble nonamphiphilic organic salts with fused aromatic rings in aqueous solutions. The nonamphiphilic organic salts are in turn promoted to form droplets of water-based liquid crystals (chromonic liquid crystals) encapsulated by single-chain surfactants. The droplets, stabilized against coalescence by encapsulated in a layer (or layers) of single chain surfactants, are of both nonspherical tactoid (elongated ellipsoid with pointy ends) and spherical shapes. The tactoids have an average long axis of ∼9 μm and a short axis of ∼3.5 μm with the liquid crystal aligning parallel to the droplet surface. The spherical droplets are 5-10 μm in diameter and have the liquid crystal aligning perpendicular to the droplet surface and a point defect in the center. Cationic and zwitterionic surfactants studied in this work did not promote the organic salt to form droplets. These results illustrate the complex interplay of self-association and thermodynamic incompatibility of molecules in water, which can cause new assembly behavior, including potential formation of vesicles or other assemblies, from surfactants that usually form only micelles. These unprecedented tactoidal shaped droplets also provide potential for the fabrication of new soft organic microcapsules.

  5. Gemini型表面活性剂在离子液体中构筑的溶致液晶%Lyotropic liquid crystalline phases formed by Gemini surfactants in anionic liquid

    Institute of Scientific and Technical Information of China (English)

    宋冰蕾; 陈涛; 田金年; 裴晓梅; 孟丽

    2015-01-01

    通过差示扫描量热仪(DSC)、X 射线衍射仪(XRD)、热台偏光显微镜(POM)和红外光谱仪等手段研究了Gemini表面活性剂在硝酸乙基铵(EAN)中构筑的溶致液晶体系(lyotropic liquid crystal,LLc)的性质.结果表明,在液晶区内,所形成的溶致液晶均为层状介晶A相(SmA),且EAN主要存在于液晶相分子层的极性亚层中;液晶相稳定存在的温度区间随Gemini表面活性剂的浓度、尾链长度的增加而变大,随联接链的增加表现出先增大再减小的趋势;羟基削弱了离子头基与反离子间的相互作用,进而缩小了液晶相稳定存在的温度区间.%The lyotropic liquid crystals formed by Gemini surfactants in ethyl ammonium nitrate (EAN) were investigated by differential scanning calorimetry(DSC),X ray diffractometer(XRD),polarizing microscope(POM) equipped with a hot stage and FTIR. All the surfactants form smectic A phase(SmA) in liquid crystalline region. The EAN molecules mainly exist in the polar sublayers of liquid crystals. The temperature ranges of liquid crystal phase increase with increasing Gemini surfactant alkyl chain length while show maximum with the increase of spacer length. The hydroxyl groups decrease the interactions between the ionic head groups and counterions. The temperature range of liquid crystal state is thus narrowed.

  6. Cooperativity of the assembly process in a low concentration chromonic liquid crystal.

    Science.gov (United States)

    Mercado, Benjamin R; Nieser, Kenneth J; Collings, Peter J

    2014-11-20

    IR-806 is a near-infrared cyanine dye that undergoes a two-step assembly process in aqueous solutions. The final assemblies orientationally order into a liquid crystal at a very low concentration (∼0.6 wt % at room temperature). While the first step of the assembly process is continuous as the dye concentration or temperature is varied (isodesmic), the second step is more abrupt (cooperative). Because the absorption spectrum of IR-806 changes dramatically during the assembly process, careful equilibrium and kinetic absorption experiments are utilized to examine the details of the cooperative second step. These experiments involve changes in both concentration and temperature, allowing a close thermodynamic analysis of the assembly process. Both equilibrium and kinetic investigations reveal that the assembly process is highly cooperative and can be described by multiple models (for example, nucleation and growth) in the highly cooperative limit. The enthalpy associated with the growth process and the activation energy of the rate-limiting step during disassembly are determined. These findings have significant implications for the structure of the assemblies that form the liquid crystal phase in IR-806.

  7. Self-assembly and UV-curing Property of Polymerized Lyotropic Liquid Crystal Monomer of Sodium 3,4,5-tris(11-acryloxyundecyloxy)benzoate

    Institute of Scientific and Technical Information of China (English)

    Yu-qin Bai; Jin-bao Guo; Ying Wang; Jie Wei

    2013-01-01

    A polymerized lyotropic liquid crystal monomer of sodium 3,4,5-tris (11-acryloxyundecyloxy)benzoate was synthesized by a convenient route starting from 3,4,5-trihydroxybenzoic acid via esterification followed by etherification,acylation and finally neutralization.The chemical structure was confirmed by Fourier transform infrared (FT-IR) and 1H nuclear magnetic resonance spectral analysis.The self-organization behavior of the monomer with deionized water in methanol at room temperature was also demonstrated.The assemblies were characterized by polarized optical microscope and X-ray diffraction.The results show that a solution containing 80∶20 of the monomer to water was found to be able to self-organize into Lamellar (La) phase and 92∶8 with inverted hexagonal (HⅡ) phase,which was in accordance with the theoretical calculation of critical packing parameter.It suggests that the concentration of the monomer was the key factor to influence assembly structure.Additionally,the acrylate conversion with different photoinitiators and nanostructure retention after polymerization were investigated.The research shows that the acrylate conversion of the monomer with Darocur2959 could reach up to 78% when irradiated by 30 mW/cm2 UV light of 365 nm for 30 min characterized by Real-time FT-IR as well as the sol-gel method.Meanwhile,the La and HⅡI phase nanostructures were both retained after polymerization.

  8. A molecular design principle of lyotropic liquid-crystalline conjugated polymers with directed alignment capability for plastic electronics.

    Science.gov (United States)

    Kim, Bong-Gi; Jeong, Eun Jeong; Chung, Jong Won; Seo, Sungbaek; Koo, Bonwon; Kim, Jinsang

    2013-07-01

    Conjugated polymers with a one-dimensional p-orbital overlap exhibit optoelectronic anisotropy. Their unique anisotropic properties can be fully realized in device applications only when the conjugated chains are aligned. Here, we report a molecular design principle of conjugated polymers to achieve concentration-regulated chain planarization, self-assembly, liquid-crystal-like good mobility and non-interdigitated side chains. As a consequence of these intra- and intermolecular attributes, chain alignment along an applied flow field occurs. This liquid-crystalline conjugated polymer was realized by incorporating intramolecular sulphur-fluorine interactions and bulky side chains linked to a tetrahedral carbon having a large form factor. By optimizing the polymer concentration and the flow field, we could achieve a high dichroic ratio of 16.67 in emission from conducting conjugated polymer films. Two-dimensional grazing-incidence X-ray diffraction was performed to analyse a well-defined conjugated polymer alignment. Thin-film transistors built on highly aligned conjugated polymer films showed more than three orders of magnitude faster carrier mobility along the conjugated polymer alignment direction than the perpendicular direction.

  9. Doping silver nanoparticles in AOT lyotropic lamellarphases

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The organic lyotropic liquid crystal with long-range structural order is used as templateto assemble inorganic/organic hybrid by doping pre-fabricated Ag nanoparticles. The lamellar hy-brid with both hydrophilic and hydrophobic particles doped simultaneously is realized for the firsttime. The change of template structure after doping and the stability origin of dual-doped systemare characterized by small angle X-ray scattering and polarized optical microscopy. Results showthat the interaction and space matching between surfactant bilayers and doped particles are

  10. Formation of a 1,8-octanedithiol self-assembled monolayer on Au(111) prepared in a lyotropic liquid-crystalline medium.

    Science.gov (United States)

    García Raya, Daniel; Madueño, Rafael; Blázquez, Manuel; Pineda, Teresa

    2010-07-20

    A characterization of the 1,8-octanedithiol (ODT) self-assembled monolayer (SAM) formed from a Triton X-100 lyotropic medium has been conducted by electrochemical techniques. It is found that an ODT layer of standing-up molecules is obtained at short modification time without removing oxygen from the medium. The electrochemical study shows that the ODT layer formed after 15 min of modification time has similar electron-transfer blocking properties to the layers formed from organic solvents at much longer modification times. On the basis of XPS data, it is demonstrated that the inability to bind gold nanoparticles (AuNPs) is due to the presence of extra ODT molecules either interdigited or on top of the layer. Treatment consisting of an acid washing step following the formation of the ODT-Au(111) SAM produces a layer that is able to attach AuNPs as demonstrated by electrochemical techniques and atomic force microscopy (AFM) images.

  11. Analysis of 2-(2-Phenylethyl)chromones by UPLC-ESI-QTOF-MS and Multivariate Statistical Methods in Wild and Cultivated Agarwood.

    Science.gov (United States)

    Li, Yuanbin; Sheng, Nan; Wang, Lingli; Li, Shijie; Chen, Jiannan; Lai, Xiaoping

    2016-05-23

    Agarwood is the fragrant resinous material mainly formed from species of Aquilaria. 2-(2-phenylethyl)chromones, especially the highly oxidized 5,6,7,8-tetrahydro-2-(2-phenylethyl)chromones, are the main representative compounds from agarwood. It is important to determine whether agarwood in trade is from cultivated trees or natural trees in the Convention on the International Trade in Endangered Species (CITES). We characterized the 2-(2-phenylethyl)chromones in agarwood by ultra-performance liquid chromatography coupled with electrospray ionization mass spectrometry (UPLC-ESI-QTOF-MS) and differentiated wild from cultivated agarwood by metabolomic analysis. A total of 141 chromones including 50 potentially new compounds were evaluated as belonging to four structural classes (unoxidized 2-(2-phenylethyl)chromones, 5,6,7,8-tetrahydro-2-(2-phenylethyl)-chromones, bi-2-(2-phenylethyl)chromones, and tri-2-(2-phenylethyl)chromones). The metabolic difference between wild and cultivated agarwood was analyzed by component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA). Fourteen markers of metabolisms in wild and cultivated agarwood were constructed (e.g., 6,7-dimethoxy-2-(2-phenylethyl)chromone, 6,8-dihydroxy-2-(2-phenylethyl)chromone, 6-methoxy-2-(2-phenylethyl)chromone, etc.). These results indicated that UPLC-ESI-QTOF-MS-based metabonomics analysis in agarwood may be useful for distinguishing wild agarwood from cultivated agarwood.

  12. A novel lyotropic liquid crystal formed by triphilic star-polyphiles: hydrophilic/oleophilic/fluorophilic rods arranged in a 12.6.4. tiling

    DEFF Research Database (Denmark)

    de Campo, Liliana; Varslot, Trond; Moghaddam, Minoo J.

    2011-01-01

    Triphilic star-polyphiles are short-chain oligomeric molecules with a radial arrangement of hydrophilic, hydrocarbon and fluorocarbon chains linked to a common centre. They form a number of liquid crystalline structures when mixed with water. In this contribution we focus on a hexagonal liquid cr...

  13. pH controlled release of chromone from chromone-Fe3O4 nanoparticles.

    Science.gov (United States)

    Wang, Baodui; Xu, Chenjie; Xie, Jin; Yang, Zhengyin; Sun, Shouheng

    2008-11-05

    We report a new strategy for coupling chromone to Fe3O4 nanoparticles. The chromone-Fe3O4 NP conjugate shows a dramatic increase in chromone solubility in cell culture medium from less than 2.5 to 633 microg/ml, leading to the enhanced chromone uptake by HeLa cells. Chromone can be released at low pH and as a result, the chromone-Fe3O4 conjugate is much more efficient in inhibiting the HeLa cell proliferation. Such chromone-Fe3O4 NPs are promising as a powerful multifunctional delivery system for both chromone-based diagnostic and therapeutic applications.

  14. Domino reactions of 2-methyl chromones containing an electron withdrawing group with chromone-fused dienes.

    Science.gov (United States)

    Gong, Jian; Xie, Fuchun; Ren, Wenming; Chen, Hong; Hu, Youhong

    2012-01-21

    Domino reactions of 2-methyl substituted chromones containing an electron withdrawing group at the 3-position with chromone-fused dienes synthesized a diverse range of benzo[a]xanthones and complicated chromone derivatives. These multiple-step reactions result in either two or three new C-C bonds without a transition metal catalyst or an inert atmosphere.

  15. Doping silver nanoparticles in AOT lyotropic lamellarphases

    Institute of Scientific and Technical Information of China (English)

    CHEN; Xiao

    2001-01-01

    aerosol OT/water/oil system, J. Colloid Interface Sci., 1979, 70: 577-583.[15]Fontell, K., The structure of the lamellar liquid crystalline phase in serosol OT-water system, J. Colloid Interface Sci.,1973, 44: 318-329.[16]Kotlarchyk, M., Sheu, E. Y., Capel, M., Structural and dynamical transformations between neighboring dense microemulsion phases, Phys. Rev. A, 1992, 46: 928-939.[17]Antelmi, D. A., Kekicheff, P., Measurement of the compressibility modulus in a lyotropic lamellar phase stabilized by undulation forces, J. Phys. Chem. B, 1997, 101: 8169-8179.[18]Wang, W., Efrima, S., Regev, O., Directing silver nanoparticles into colloid-surfactant lyotropic lamellar systems, J. Phys.Chem. B, 1999, 103: 5613-5621.[19]Chidichimo, G., La Mesa, C., Ranieri, G. A. et al., NMR investigation of the lamellar mesophase occuring in the system aerosol OT-water, Mol. Cryst. Liq. Cryst., 1987, 150b: 221-236.[20]Callaghan, P. T., Soderman, O., Examination of the lamellar phase of aerosol OT/water using pulsed field gradient nuclear magnetic resonance, J. Phys. Chem., 1983, 87: 1737-744.

  16. PEGylation of Phytantriol-Based Lyotropic Liquid Crystalline Particles-The Effect of Lipid Composition, PEG Chain Length, and Temperature on the Internal Nanostructure

    DEFF Research Database (Denmark)

    Nilsson, Christa; Ostergaard, Jesper; Larsen, Susan Weng

    2014-01-01

    on phytantriol (PHYT) were investigated by means of synchrotron small-angle X-ray scattering and Transmission Electron Cryo-Microscopy. The results suggest that the used lipopolymers are incorporated into the water-PHYT interfacial area and induce a significant effect on the internal nanostructures...... injectable long-circulating drug nanocarriers based on cubosomes and hexosomes by shielding and coating the dispersed particles enveloping well-defined internal nonlamellar liquid crystalline nanostructures with hydrophilic PEG segments. The present study attempts to shed light on the possible PEGylation...... of these lipidic nonlamellar liquid crystalline particles by using DSPE-mPEGs with three different block lengths of the hydrophilic PEG segment. The effects of lipid composition, PEG chain length, and temperature on the morphology and internal nanostructure of these self-assembled lipidic aqueous dispersions based...

  17. PEGylation of phytantriol-based lyotropic liquid crystalline particles--the effect of lipid composition, PEG chain length, and temperature on the internal nanostructure.

    Science.gov (United States)

    Nilsson, Christa; Østergaard, Jesper; Larsen, Susan Weng; Larsen, Claus; Urtti, Arto; Yaghmur, Anan

    2014-06-10

    Poly(ethylene glycol)-grafted 1,2-distearoyl-sn-glycero-3-phosphoethanolamines (DSPE-mPEGs) are a family of amphiphilic lipopolymers attractive in formulating injectable long-circulating nanoparticulate drug formulations. In addition to long circulating liposomes, there is an interest in developing injectable long-circulating drug nanocarriers based on cubosomes and hexosomes by shielding and coating the dispersed particles enveloping well-defined internal nonlamellar liquid crystalline nanostructures with hydrophilic PEG segments. The present study attempts to shed light on the possible PEGylation of these lipidic nonlamellar liquid crystalline particles by using DSPE-mPEGs with three different block lengths of the hydrophilic PEG segment. The effects of lipid composition, PEG chain length, and temperature on the morphology and internal nanostructure of these self-assembled lipidic aqueous dispersions based on phytantriol (PHYT) were investigated by means of synchrotron small-angle X-ray scattering and Transmission Electron Cryo-Microscopy. The results suggest that the used lipopolymers are incorporated into the water-PHYT interfacial area and induce a significant effect on the internal nanostructures of the dispersed submicrometer-sized particles. The hydrophilic domains of the internal liquid crystalline nanostructures of these aqueous dispersions are functionalized, i.e., the hydrophilic nanochannels of the internal cubic Pn3m and Im3m phases are significantly enlarged in the presence of relatively small amounts of the used DSPE-mPEGs. It is evident that the partial replacement of PHYT by these PEGylated lipids could be an attractive approach for the surface modification of cubosomal and hexosomal particles. These PEGylated nanocarriers are particularly attractive in designing injectable cubosomal and hexosomal nanocarriers for loading drugs and/or imaging probes.

  18. Lyotropic, liquid crystalline nanostructures of aqueous dilutions of SMEDDS revealed by small-angle X-ray scattering: impact on solubility and drug release.

    Science.gov (United States)

    Goddeeris, Caroline; Goderis, Bart; Van den Mooter, Guy

    2010-05-12

    The present study was conducted to characterise the liquid crystalline phases that occur upon diluting a SMEDDS and to elucidate the role of these phases on drug solubilisation and release. Small-angle X-ray scattering (SAXS) was used to probe the structures in aqueous dilutions of 3 SMEDDS consisting of propylene glycol mono- and dicaprylate and mono- and dicaprate (PGDCDC) and d-alpha-tocopheryl polyethylene glycol succinate 1000 (TPGS 1000), polysorbate 80 (P80) or polyoxyl 40 hydrogenated castor oil (P40HC). The scattering patterns revealed the formation of either a random periodic or a lamellar phase when 10% (w/w) water was added. All formulations exhibited lamellar structures at 20% (w/w) aqueous dilution, of which the layer-to-layer distance increased upon further addition of water. At 40% (w/w) water, a hexagonal or lamellar phase was formed, depending on the geometry of the surfactant. Temperature did not alter the phases formed. Incorporation of the drug UC 781 only slightly enlarged the characteristic dimensions of the liquid crystalline phases. Drug solubility decreased upon aqueous dilution, although 10% (w/w) dilutions of PGDCDC-P80 SMEDDS and PGDCDC-TPGS 1000 SMEDDS revealed a highly increased solubility as compared to the pure formulations. Drug release data revealed that UC 781 release could not be linked to the solubilisation capacity of the SMEDDS, but could be associated with the solubility of UC 781 in the phases formed at water concentrations above 10% (w/w).

  19. Stealth, biocompatible monoolein-based lyotropic liquid crystalline nanoparticles for enhanced aloe-emodin delivery to breast cancer cells: in vitro and in vivo studies.

    Science.gov (United States)

    Freag, May S; Elnaggar, Yosra Sr; Abdelmonsif, Doaa A; Abdallah, Ossama Y

    Recently, research has progressively highlighted on clues from conventional use of herbal medicines to introduce new anticancer drugs. Aloe-emodin (AE) is a herbal drug with promising anticancer activity. Nevertheless, its clinical utility is handicapped by its low solubility. For the first time, this study aims to the fabrication of surface-functionalized polyethylene glycol liquid crystalline nanoparticles (PEG-LCNPs) of AE to enhance its water solubility and enable its anticancer use. Developed AE-PEG-LCNPs were optimized via particle size and zeta potential measurements. Phase behavior, solid state characteristics, hemocompatibility, and serum stability of LCNPs were assessed. Sterile formulations were developed using various sterilization technologies. Furthermore, the potential of the formulations was investigated using cell culture, pharmacokinetics, biodistribution, and toxicity studies. AE-PEG-LCNPs showed particle size of 190 nm and zeta potential of -49.9, and PEGylation approach reduced the monoolein hemolytic tendency to 3% and increased the serum stability of the nanoparticles. Sterilization of liquid and lyophilized AE-PEG-LCNPs via autoclaving and γ-radiations, respectively, insignificantly affected the physicochemical properties of the nanoparticles. Half maximal inhibitory concentration of AE-PEG-LCNPs was 3.6-fold lower than free AE after 48 hours and their cellular uptake was threefold higher than free AE after 24-hour incubation. AE-PEG-LCNPs presented 5.4-fold increase in t1/2 compared with free AE. Biodistribution and toxicity studies showed reduced AE-PEG-LCNP uptake by reticuloendothelial system organs and good safety profile. PEGylated LCNPs could serve as a promising nanocarrier for efficient delivery of AE to cancerous cells.

  20. Chromones from an ascomycete,Chaetomium aureus

    Institute of Scientific and Technical Information of China (English)

    Li Mei Li; Qiang Zou; Guo You Li

    2010-01-01

    A novel chromone,named chaetoaurin (1),along with six known chromone derivatives (2-7),was isolated from the ethyl acetate extract of a solid-state fermented culture of Chaetomium aureus.Their structures were elucidated by extensive spectral analysis.All of these compounds were reported from C.aureus for the first time.

  1. [Preparative isolation and purification of cinnamoyl-C-glycoside chromone from aloe vera by high-speed countercurrent chromatography].

    Science.gov (United States)

    Pan, Xia; Cao, Xueli; Dong, Yinmao; Zhao, Hua

    2005-01-01

    Aloe chromone is a group of anti-inflammatory and anti-tyrosinase constituents found in aloe vera leaves. High-speed countercurrent chromatography (HSCCC) is reported for the preparative isolation and purification of a chromone from aloe vera. The crude extract was obtained by a series of pretreatment of aloe vera leaves and extracted from decolorizing active carbon with methanol. Then the extract was distributed between dichloromethane and water, and the organic part was then subjected to HSCCC for the isolation of chromone constituents. The chromone compounds with a high performance liquid chromatographic grade (>95%) was isolated through two step HSCCC separations by employing two solvent systems composed of chloroform-methanol-water and dichloromethane-methanol-water at volume ratios of 4/3/2 and 5/4/2, respectively. The chromone was finally identified as cinnamoyl-C-glycoside chromone by ultraviolet (UV), fast atom bombardment mass spectrometry (FAB-MS), nuclear magnetic resonance (1H NMR and 13C NMR).

  2. A new chromone derivative from Berchemia lineata.

    Science.gov (United States)

    Shen, Yu-xia; Teng, Hong-li; Yang, Guang-zhong; Mei, Zhi-nan; Chen, Xiao-long

    2010-09-01

    To study the chemical constituents from the root of Berchemia lineata (L.) DC., nine compounds were isolated from the EtOAc extract by using silica gel, RP-C18 silica gel column chromatography and preparative HPLC. Based on the spectroscopic analysis, their structures were identified as 5-hydroxy-7-(2'-hydroxypropyl)-2-methyl-chromone (1), (-)-(1'R, 2'S)-erythro-5-hydroxy-7-(1', 2'-dihydroxypropyl)-2-methyl-chromone (2), naringenin (3), eriodictyol (4), (+)-aromadendrin (5), (+)-taxifolin (6), (+)-catechin (7), (+)-epigallocatechin (8) and quercetin (9). Among them, compound 2 is a new chromone derivative. Compound 1 is a known chromone derivative and isolated from this genus for the first time. Compounds 3-9 are known flavonoids and isolated from this plant for the first time.

  3. Syntheses of 2- or 6-Substituted Chromones and Chromone Ring-opening Reaction in Polyphosphoric Acid

    Institute of Scientific and Technical Information of China (English)

    HE Xun-gui; YOU Qi-dong; LI Zhi-yu

    2004-01-01

    In an attempt to find new antitumor agents, a novel class of chromone compounds with a benzimidazole or a benzoxazole ring in positions 2 or 6 were synthesized via condensation in polyphosphoric acid(PPA) by using chromone acids as the starting materials. During the preparation process, it was found that PPA could cleave the chromone ring to produce a ring-opening compound(6). The molar ratio of the chromone compound(5) to the ring-opening compound(6) varied with the change of reaction temperature and time. Based on MTT protocol, the antitumor activity of each of the compounds obtained was evaluated against three human cancer cell lines: KB(oral epidermal), A2780(ovary) and Bel7402(liver). The IC50 varied from 54.7 μmol/L to more than 180 μmol/L.

  4. Two New Chromone Glycosides from Selaginella uncinata

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Two new chromone glycosides, 5-hydroxy-2,6,8-trimethylchromon-7-O-β-D-gluco-pyranoside, named uncinoside A; 5-acetoxy-2,6,8-trimethylchromone-7-O-β-D-glucopyranoside, named uncinoside B, and a known chromone compound named 8-methyl eugenitol were isolated from Selaginella uncinata. Their structures were elucidated by spectra analysis of FAB-MS, 1D NMR and 2D NMR including 1H NMR, 13C NMR, HMQC, HMBC and single-crystal X-ray diffraction techniques.

  5. Diversifying the solid state and lyotropic phase behavior of nonionic urea-based surfactants.

    Science.gov (United States)

    Fong, Celesta; Wells, Darrell; Krodkiewska, Irena; Weerawardeena, Asoka; Booth, Jamie; Hartley, Patrick G; Drummond, Calum J

    2007-09-13

    The solid state and lyotropic phase behavior of 10 new nonionic urea-based surfactants has been characterized. The strong homo-urea interaction, which can prevent urea surfactants from forming lyotropic liquid crystalline phases, has been ameliorated through the use of isoprenoid hydrocarbon tails such as phytanyl (3,7,11,15-tetramethyl-hexadecyl) and hexahydrofarnesyl (3,7,11-trimethyl-dodecyl) or the oleyl chain (cis-octadec-9-enyl). Additionally, the urea head group was modified by attaching either a hydroxy alkyl (short chain alcohol) moiety to one of the nitrogens of the urea or by effectively "doubling" the urea head group by replacing it with a biuret head group. The solid state phase behavior, including the liquid crystal-isotropic liquid, polymorphic, and glass transitions, is interpreted in terms of molecular geometries and probable hydrogen-bonding interactions. Four of the modified urea surfactants displayed ordered lyotropic liquid crystalline phases that were stable in excess water at both room and physiological temperatures, namely, 1-(2-hydroxyethyl)-1-oleyl urea (oleyl 1,1-HEU) with a 1D lamellar phase (Lalpha), 1-(2-hydroxyethyl)-3-phytanyl urea (Phyt 1,3-HEU) with a 2D inverse hexagonal phase (HII), and 1-(2-hydroxyethyl)-1-phytanyl urea (Phyt 1,1-HEU) and 1-(2-hydroxyethyl)-3-hexahydrofarnesyl urea (Hfarn 1,3-HEU) with a 3D bicontinuous cubic phase (QII). Phyt 1,1-HEU exhibited rich mesomorphism (QII1, QII2, Lalpha, LU, and HII), as did one other surfactant, oleyl 1,3-HEU (QII1, QII2, Lalpha, LU, and HII), in the study group. LU is an unusual phase which is mobile and isotropic but possesses shear birefringence, and has been very tentatively assigned as an inverse sponge phase. Three other surfactants exhibited a single lyotropic liquid crystalline phase, either Lalpha or HII, at temperatures >50 degrees C. The 10 new surfactants are compared with other recently reported nonionic urea surfactants. Structure-property correlations are examined for

  6. Coumarins and Chromones from ’Lomatium macrocarpum’,

    Science.gov (United States)

    Roots of Lomatium macrocarpum (Hook. and Arn.)C. and R. yielded osthol(7-methoxy-8-(3-methyl-2-butenyl)-coumarin) and a chromone , 2-methyl-5-hydroxy...6(3-methyl-2-butenyl)-7-methoxychromone, identified spectroscopically and by synthesis. The serial parts of the plant also contained this chromone

  7. Selected chromone derivatives as inhibitors of monoamine oxidase.

    Science.gov (United States)

    Legoabe, Lesetja J; Petzer, Anél; Petzer, Jacobus P

    2012-09-01

    A previous study has shown that a series of C6-benzyloxy substituted chromones exhibit high binding affinities for human monoamine oxidase (MAO) B. In an attempt to discover additional chromones with potent and selective MAO-B inhibitory potencies and to further examine the structure-activity relationships of MAO-B inhibition by chromones, the series was expanded with homologues containing polar functional groups on C3 of the chromone ring. The results demonstrate that 6-[(3-bromobenzyl)oxy]chromones containing acidic and aldehydic functional groups on C3 act as potent reversible MAO-B inhibitors with IC(50) values of 2.8 and 3.7 nM, respectively. Interestingly, a 2-hydroxy-2,3-dihydro-1-benzopyran-4-one derivative as well as open-ring 2-acetylphenol analogues of the chromones also were potent MAO-B inhibitors with IC(50) values ranging from 4 to 11 nM. Chromone derivatives containing the benzyloxy substituent on C5 of the chromone ring, however, exhibit MAO-B inhibition potencies that are several orders of magnitude weaker. High potency inhibitors of MAO-B may find application in the therapy of neurodegenerative disorders such as Parkinson's disease. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. NEW 2-(2-PHENYLETHYL) CHROMONES FROM BOTHRIOCHLOA ISCHAEMUM

    Institute of Scientific and Technical Information of China (English)

    TAO WANG; LAN-FANG LI; KUI ZHANG; WEN-YAN ZHANG; YUE-HU PEI

    2001-01-01

    Two new 2-(2-Phenylethyl) chromones were isolated from Bothriochloa ischaemum (Grami neae). They were characterized as 5-hydroxy-6-methoxy-2-[2-(2-hydroxyphenyl)-ethyl]-chro mone(1) and 5-hydroxy-2-[2-(2-hydroxyphenyl)-ethyl]-chromone(2) by means of spectroscopic analysis, especially 2D-NMR experiments.

  9. A novel synthesis of chromone based unnatural α-amino acid derivatives

    Indian Academy of Sciences (India)

    VENU KANDULA; RAMAKRISHNA GUDIPATI; ANINDITA CHATTERJEE; MURALIDARAN KALIYAPERUMALA; SATYANARAYANA YENNAM; MANORANJAN BEHERA

    2017-08-01

    An efficient method for the preparation of chromone based α-amino acid derivatives by alkylation of glycinate schiff base with 3-bromomethyl chromone as well as 2-bromomethyl chromone has been described. Using this method, 2-amino-3-(4-oxo-2-chromenyl)propanoic acid and 2-amino-3-(4-oxo-3- chromenyl)propanoic acid, two novel chromone-amino acid conjugates have been prepared. Furthermore, the separation of chromone amino acid enantiomers by chiral column chromatography was accomplished.

  10. Studies on the phase properties of lyotropic liquid crystals of Brij35/sodium oleate/oleic acid/water system: By means of polarizing microscope, SAXS, 2H-NMR and rheological methods

    Institute of Scientific and Technical Information of China (English)

    AN Ya; XU Jun; ZHANG Jin; HU Changgang; LI Ganzuo; WANG Zhining; WANG Zhongni; ZHANG Xiaoyi; ZHENG Liqiang

    2006-01-01

    The pseudo-quaternary phase diagram of Brij35/sodium oleate/oleic acid/water systems has been investigated, and the liquid crystal area has been identified, which covers about two thirds of the whole phase diagram. The liquid crystal structure and behavior have been also studied by using polarizing texture, small angle X-ray scattering, 2H-NMR and rheometer etc. The result shows that when the composition of the system changes along the line of AA' in this large liquid crystal region, the structural change is cubic→cubic/lamellar→lamellar→lamellar/hexagonal→hexagonal. Meanwhile, we made the first attempt of systematic study of the rheological properties of the above system. The lattice constants of cubic and hexagonal liquid crystals are 10.53 and 5.68 nm, respectively.

  11. Design, synthesis and antiviral activity of 2-(3-amino-4-piperazinylphenyl)chromone derivatives.

    Science.gov (United States)

    Kim, Mi Kyoung; Yoon, Hyunjun; Barnard, Dale Lynn; Chong, Youhoon

    2013-01-01

    Previously, we have confirmed that the antiviral activities of the chromone derivatives were controlled by the type as well as the position of the substituents attached to the chromone core structure. In the course of our ongoing efforts to optimize the antiviral activity of the chromone derivatives, we have been attempting to derivatize the chromone scaffold via introduction of various substituents. In this proof-of-concept study, we introduced a 3-amino-4-piperazinylphenyl functionality to the chromone scaffold and evaluated the antiviral activities of the resulting chromone derivatives. The synthesized 2-(3-amino-4-piperazinylphenyl)-chromones showed severe acute respiratory syndrome-corona virus (SARS-CoV)-specific antiviral activity. In particular, the 2-pyridinylpiperazinylphenyl substituents provided the resulting chromone derivatives with selective antiviral activity. Taken together, this result indicates the possible pharmacophoric role of the 2-pyridinylpiperazine functionality attached to the chromone scaffold, which warrants further in-depth structure-activity relationship study.

  12. A new chromone from Angelica polymorpha with cytotoxic activity.

    Science.gov (United States)

    Yang, Shang-Jun; Yao, Qing-Qiang; Li, Ye-Na; Chen, Xiao-Xiao; Cui, Shu-Xiang; Bai, Shao-Yan; Wang, Feng-Ling

    2012-01-01

    A new chromone polymorchromone B was isolated and characterized from the roots of Angelica polymorpha Maxim, a commonly used traditional Chinese medicine. On the basis of spectroscopic analysis, including IR, HR-ESI-MS, 1D and 2D NMR spectral data, and hydrolysis followed by chromatographic analysis, the structure of the new chromone was elucidated as 5-hydroxy-2-[(angeloyloxy)methyl]-2'-(dimethyl)-3'-(2S,3S-epoxy-2-methylbutanoate)-dihydropyran [3',2':6,7]chromone. Moreover, it was found that polymorchromone B showed remarkable cytotoxic activity against A-549 cell lines.

  13. Synthesis and NMR studies of novel chromone-2-carboxamide derivatives.

    Science.gov (United States)

    Gaspar, Alexandra; Cagide, Fernando; Quezada, Elias; Reis, Joana; Uriarte, Eugenio; Borges, Fernanda

    2013-04-01

    Chromones are heterocyclic compounds of natural or synthetic origin that possess relevant pharmacological activities. Versatile functionalization of the chromone nucleus allows attaining of a chemical diversity suitable to perform structure-activity relationships in drug discovery and development programs. Accordingly, the synthesis and identification of novel chromone carboxamide derivatives with electron-donating and electron-withdrawing substituents in different positions of the exocyclic ring are reported in this work. Their complete structural characterization was performed using one-dimensional and two-dimensional resonance techniques. The data acquired are useful for a prompt analysis of related compounds that encompass our integrated medicinal chemistry sketch. Copyright © 2013 John Wiley & Sons, Ltd.

  14. Chromone and Flavonoid Alkaloids: Occurrence and Bioactivity

    Directory of Open Access Journals (Sweden)

    Robin J. Marles

    2011-12-01

    Full Text Available The chromone and flavonoid alkaloids represent an unusual group of structurally diverse secondary metabolites, derived from the convergence of multiple biosynthetic pathways that are widely distributed through the plant and animal kingdoms. Many of them have been discovered through bioassay-guided chemical investigations of traditional medicines, suggesting potential therapeutic significance. Their unique structures and varied pharmacological activities may provide important new leads for the discovery of drugs with novel mechanisms of action. Potential therapeutic indications are as diverse as cancer and viral infections, inflammation and immunomodulation, neurological and psychiatric conditions, and diabetes.

  15. Structural, ac conductivity and dielectric properties of 3-formyl chromone

    Science.gov (United States)

    Ali, H. A. M.

    2017-07-01

    The structure for the powder of 3-formyl chromone was examined by X-ray diffraction technique in the 2θ° range ( 4° - 60° . The configuration of Al/3-formyl chromone/Al samples was designed. The electrical and dielectric properties were studied as a function of frequency (42- 5 × 106 Hz) and temperature (298-408K). The ac conductivity data of bulk of 3-formyl chromone varies as a power law with the frequency at different temperatures. The predominant mechanism for ac conduction was deduced. The ac conductivity shows a thermally activated process at different frequencies. The dielectric constant and dielectric loss were determined using the capacitance and dissipation factor measurements at different temperatures. The dielectric loss shows a peak of relaxation time that shifted to higher frequency with an increase in the temperature. The activation energy of the relaxation process was estimated.

  16. In vitro antioxidant activity study of novel chromone derivatives.

    Science.gov (United States)

    Phosrithong, Narumol; Samee, Weerasak; Nunthanavanit, Patcharawee; Ungwitayatorn, Jiraporn

    2012-06-01

    Forty-eight chromone derivatives were evaluated for their antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl free radical scavenging assay, ferrous ions (Fe(2+) ) chelating activity test, total antioxidant activity test (Ferric thiocyanate and Thiobarbituric acid methods), and total reductive capability (potassium ferricyanide reduction). 7,8-Dihydroxy-2-(3'-trifluoromethylphenyl)-3-(3″-trifluoromethylbenzoyl) chromone 32 showed stronger radical scavenging and metal chelating activities than butylated hydroxytoluene, vitamin E, and trolox. Chromone derivatives that exhibited good radical scavenging and metal chelating also displayed strong total antioxidant and reductive power activities. The results obtained from this study indicated that the synthesized chromone derivatives have remarkable antioxidant activity. © 2012 John Wiley & Sons A/S.

  17. Selected C7-substituted chromone derivatives as monoamine oxidase inhibitors.

    Science.gov (United States)

    Legoabe, Lesetja J; Petzer, Anél; Petzer, Jacobus P

    2012-12-01

    A series of C7-substituted chromone (1-benzopyran-4-one) derivatives were synthesized and evaluated as inhibitors of recombinant human monoamine oxidase (MAO) A and B. The chromones are structurally related to a series of C7-functionalized coumarin (1-benzopyran-2-one) derivatives which has been reported to act as potent MAO inhibitors. The results of the current study document that the chromones are highly potent reversible inhibitors of MAO-B with IC(50) values ranging from 0.008 to 0.370 μM. While the chromone derivatives also exhibit affinities for MAO-A, with IC(50) values ranging from 0.495 to 8.03 μM, they are selective for the MAO-B isoform. Structure-activity relationships (SAR) show that 7-benzyloxy substitution of chromone is suitable for MAO-B inhibition with tolerance for a variety of substituents and substitution patterns on the benzyloxy ring. It may be concluded that 7-benzyloxychromones are appropriate lead compounds for the design of reversible and selective MAO-B inhibitors. With the aid of modeling studies, potential binding orientations and interactions of selected chromone derivatives in the MAO-A and -B active sites are examined. Copyright © 2012 Elsevier Inc. All rights reserved.

  18. Design, Synthesis and Antiviral Activity of 2-(3-Amino-4-piperazinylphenyl)chromone Derivatives

    National Research Council Canada - National Science Library

    Kim, Mi Kyoung; Yoon, Hyunjun; Barnard, Dale Lynn; Chong, Youhoon

    2013-01-01

    Previously, we have confirmed that the antiviral activities of the chromone derivatives were controlled by the type as well as the position of the substituents attached to the chromone core structure...

  19. Phase transfer reagent promoted tandem ring-opening and ring-closing reactions of unique 3-(1-alkynyl) chromones.

    Science.gov (United States)

    Liu, Yang; Jin, Shiyu; Huang, Liping; Hu, Youhong

    2015-05-01

    A phase transfer reagent promoted tandem ring-opening and ring-closing reaction of 3-(1-alkynyl) chromones has been developed. This process remarkably generates functionalized 3-acyl-2-substituted chromones. Interestingly, when 3-(hepta-1,6-diyn-1-yl)chromone derivatives are applied, a novel tetracyclic chromone scaffold can be obtained by a further intramolecular 4 + 2 cyclization.

  20. Inverse lyotropic phases of lipids and membrane curvature

    Energy Technology Data Exchange (ETDEWEB)

    Shearman, G C; Ces, O; Templer, R H; Seddon, J M [Department of Chemistry, Imperial College London, SW7 2AZ (United Kingdom)

    2006-07-19

    In recent years it has become evident that many biological functions and processes are associated with the adoption by cellular membranes of complex geometries, at least locally. In this paper, we initially discuss the range of self-assembled structures that lipids, the building blocks of biological membranes, may form, focusing specifically on the inverse lyotropic phases of negative interfacial mean curvature. We describe the roles of curvature elasticity and packing frustration in controlling the stability of these inverse phases, and the experimental determination of the spontaneous curvature and the curvature elastic parameters. We discuss how the lyotropic phase behaviour can be tuned by the addition of compounds such as long-chain alkanes, which can relieve packing frustration. The latter section of the paper elaborates further on the structure, geometric properties, and stability of the inverse bicontinuous cubic phases.

  1. KINETICS OF MESOPHASE FORMATION OF A LYOTROPIC AROMATIC POLYAMIDE

    Institute of Scientific and Technical Information of China (English)

    CHEN Shouxi

    1989-01-01

    The kinetics of mesophase formation of a lyotropic aromatic polyamide from isotropic state has been studied by means of depolarized light intensity. Avrami type analysis of the data gives an exponent close to 1, which suggests the nucleation followed by one-dimensional growth. No influence of blending flexible chain from nylon 6 to the aromatic polyamide on the kinetics of mesophase formation was observed.

  2. Antimalarial activity of HIV-1 protease inhibitor in chromone series.

    Science.gov (United States)

    Lerdsirisuk, Pradith; Maicheen, Chirattikan; Ungwitayatorn, Jiraporn

    2014-12-01

    Increasing parasite resistance to nearly all available antimalarial drugs becomes a serious problem to human health and necessitates the need to continue the search for new effective drugs. Recent studies have shown that clinically utilized HIV-1 protease (HIV-1 PR) inhibitors can inhibit the in vitro and in vivo growth of Plasmodium falciparum. In this study, a series of chromone derivatives possessing HIV-1 PR inhibitory activity has been tested for antimalarial activity against P. falciparum (K1 multi-drug resistant strain). Chromone 15, the potent HIV-1 PR inhibitor (IC50=0.65μM), was found to be the most potent antimalarial compound with IC50=0.95μM while primaquine and tafenoquine showed IC50=2.41 and 1.95μM, respectively. Molecular docking study of chromone compounds against plasmepsin II, an aspartic protease enzyme important in hemoglobin degradation, revealed that chromone 15 exhibited the higher binding affinity (binding energy=-13.24kcal/mol) than the known PM II inhibitors. Thus, HIV-1 PR inhibitor in chromone series has the potential to be a new class of antimalarial agent. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Solvation of chromone using combined Discrete/SCRF models

    Science.gov (United States)

    Alemán, Carlos; Galembeck, Sergio E.

    1998-06-01

    The solvation of chromone has been investigated using three different combined Discrete/SCRF models. Four chromone-H 2O complexes and one chromone-4H 2O complex were obtained from geometry optimizations at the HF/6-31G(d) level. Three SCRF methods (PCM/6-31G(d), PCM/AM1 and SM2/AM1) were applied to such complexes in order to: (1) evaluate the reliability of the combined Discrete/SCRF models; (2) investigate the effects of the explicit water molecules on the free energy of solvation; and (3) analyze the characteristics of the different solvation sites of chromone. The results show that explicit solvent molecules exert a large influence on the free energy of solvation of a given molecular system providing some information about the solvation sites. Thus, the interaction of the carbonyl oxygen of chromone with the explicit water molecules is stronger than interaction provided by the ether oxygen, providing the complexes with the former interaction a more hydrophobic free energy of solvation than those with the latter. On the other hand, the comparison of the free energies of solvation for solutes with explicit water molecules in the first hydration shell and the free energies of solvation of the molecular system computed in an all-continuum approach reveals that the combined Discrete/SCRF models constitute a very reasonable strategy.

  4. Lyotropic liquid crystalline nanoparticles of CoQ10

    DEFF Research Database (Denmark)

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

    2014-01-01

    ) and phytantriol (PLCQ). Exhaustive optimization of the process variables was carried out, and optimized lyophilized formulations were found to have particle sizes of 140.45 ± 5.47 nm and 238.42 ± 8.35 nm and a polydispersity index (PDI) of 0.15 ± 0.01 and 0.22 ± 0.03 for GLCQ and PLCQ, respectively...

  5. Glueball-Quarkonium Mixing in the Quark and Chromon Model

    CERN Document Server

    Zhang, Pengming; Xie, Ju-Jun; Yoon, J H; Cho, Y M

    2016-01-01

    The Abelian decomposition of QCD which decomposes the gluons to the color neutral binding gluons (the neurons) and the colored valence gluons (the chromons) gauge independently naturally generalizes the quark model to the quark and chromon model which can play the central role in hadron spectroscopy. We discuss how the quark and chromon model describes the glueballs and the glueball-quarkonium mixing in QCD. We present the numerical analysis of glueball-quarkonium mixing in $0^{++}$, $2^{++}$, and $0^{-+}$ sectors below 2 GeV, and show that in the $0^{++}$ sector $f_0(500)$ and $f_0(1500)$, in the $2^{++}$ sector $f_2(1950)$, and in the $0^{-+}$ sector $\\eta(1405)$ and $\\eta(1475)$ could be identified as predominantly the glueball states. We discuss the physical implications of our result.

  6. Synthesis, topoisomerase I inhibitory and cytotoxic activities of chromone derivatives.

    Science.gov (United States)

    Maicheen, Chirattikan; Jittikoon, Jiraphun; Vajragupta, Opa; Ungwitayatorn, Jiraporn

    2013-05-01

    A series of chromone derivatives were designed as potential topoisomerase I (Top I) inhibitors based on the docking simulation study. Sixteen synthesized compounds were evaluated for Top I inhibitory activity and some compounds were further tested for in vitro cytotoxic activity. The most potent inhibitor, chromone 11b showed greater inhibitory activity (IC50 = 1.46 μM) than the known Top I inhibitors, i.e., camptothecin, fisetin and morin, but inactive against breast cancer cell (MCF-7), oral cavity cancer cell (KB) and small cell lung cancer (NCI-H187). Chromone 11c, another potent inhibitor (IC50 = 6.16 μM), exhibited cytotoxic activity against KB (IC50 = 73.32 μM) and NCI-H187 (IC50 = 36.79 μM).

  7. Chromones as a privileged scaffold in drug discovery: a review.

    Science.gov (United States)

    Keri, Rangappa S; Budagumpi, Srinivasa; Pai, Ranjith Krishna; Balakrishna, R Geetha

    2014-05-06

    The chromone and its derivatives are the most important heterocyclic compounds, which is a common and integral feature of a variety of natural products and medicinal agents. These heterocycles show a variety of pharmacological properties, and change of their structure offers a high degree of diversity that has proven useful for the search of new therapeutic agents. A large volume of research has been carried out on chromone and their derivatives, which has proved the pharmacological importance of this heterocyclic nucleus. The present review focuses on the pharmacological profile of chromone derivatives in the current literature with an update of recent research findings on this nucleus and the perspectives that they hold for future research. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  8. Preparation of Mg2Al Layered Double Hydroxide Nanosheets from Triton X-100 Hexagonal Lyotropic Liquid Crystal and Their Application as Drug Carriers%Triton X-100六角液晶相中制备镁铝层状双金属氢氧化物纳米片及其药物载体应用

    Institute of Scientific and Technical Information of China (English)

    赵继宽; 谢艳芳; 徐洁; 侯万国

    2015-01-01

    A hexagonal lyotropic liquid crystal (LLC) was constructed with nonionic surfactant Triton X-100 and mixed magnesium chloride/aluminum chloride aqueous solutions. Layered double hydroxide (LDH) nanosheets (L-LDHs) were prepared using the LLC as a microreactor. A nanohybrid material of L-LDHs intercalated with a model anionic drug, diclofenac sodium (DS;DS/L-LDHs) was synthesized using an ion-exchange method. The drug-release profile of DS/L-LDH was investigated under moderate conditions, i.e., 37.0 °C and pH 7.2. The results were compared with those for common LDH flaky particles (S-LDHs) synthesized using a traditional solution coprecipitation method. The crystal ine structures, specific surface areas, and morphologies of these LDHs and DS/LDHs nanohybrids were characterized using powder X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and N2 adsorption-desorption. The results show that the L-LDH particles are less thick, and have larger specific surface areas and higher DS-loading capacities than the S-LDH particles. Drug release by the DS/L-LDH nanohybrid was clearly lower than that by the DS/S-LDH nanohybrid. This indicates that the L-LDH nanosheets are more suitable for use as drug carriers than the S-LDHs. Drug release by the DS/L-LDH nanohybrid can be described using a pesudo-second-order kinetic model, and drug diffusion through the LDH particles is the rate-limiting step. LLC can be used as a template for morphology-control ed synthesis of LDHs.%以Triton X-100六角相溶致液晶作微反应器,采用共沉淀法制备了镁铝层状双金属氢氧化物(LDHs)纳米薄片(L-LDHs).以双氯芬酸钠(DS)为药物模型分子,采用离子交换法制备了DS插层LDHs (DS/L-LDHs)纳米杂化物,在37.0°C、pH=7.2的缓冲溶液中,考察了纳米杂化物的药物释放性能,并与传统溶液共沉淀法制备的镁铝LDHs (S-LDHs)纳

  9. A new chromone from the twig of Mallotus apelta.

    Science.gov (United States)

    Lu, Tailiang; Deng, Shengping; Li, Chen; Wu, Liangdeng; Yang, Ruiyun; Li, Jun

    2014-01-01

    A new chromone, 7-hydroxy-2-hydroxymethyl-8-methoxy-4-oxo-4H-chromene-6-carboxylic acid, named melachromone, along with 13 known compounds (2-14), including chromones, flavonoids, coumarins and phenylpropane derivatives, were isolated from the twig of Mallotus apelta. Their chemical structures were elucidated by using various spectroscopic methods. Anti-tumour evaluation of the compounds suggested that compound 1 exhibited medium cytotoxic activity against KB and HeLa Cells, with IC50 values of 9.50 and 9.23 μg mL(-1), respectively.

  10. 2-(2-phenylethyl)chromones from Chinese eaglewood.

    Science.gov (United States)

    Yang, Lin; Qiao, Lirui; Xie, Dan; Yuan, Yuhe; Chen, Naihong; Dai, Jungui; Guo, Shunxing

    2012-04-01

    2-(2-Phenylethyl) chromones and a 2-(2-phenylethenyl) chromone, were isolated from the ethanolic extract of Chinese eaglewood. Their structures were determined on the basis of extensive analyses of spectroscopic data. Among those, one showed significant neuroprotective activities against both glutamate-induced and corticosterone-induced neurotoxicity in P12 pheochromocytoma and human U251 glioma cells at a concentration of 10 μM and increased cell viability by 82.2% and 86.9%, respectively. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Simulating polymer liquid crystals

    NARCIS (Netherlands)

    Bladon, P.; Frenkel, D.

    1996-01-01

    A model suitable for simulating lyotropic polymer liquid crystals (PLCs) is described. By varying the persistence length between infinity and 25, the effect of increasing flexibility on the nematic - smectic transition of a PLC with a length-to-width ratio L/D = 6 is investigated. It is found that

  12. An efficient procedure for the preparation of natural products bearing the 2-(2-phenylethyl)chromone skeleton

    Science.gov (United States)

    Williams, Dwight A.; Smith, Cameron; Zhang, Yan

    2013-01-01

    Several 2-(2-phenylethyl)chromones have been shown to possess neuroprotective activity. However, limited synthetic methods have been disclosed to construct the 2-(2-phenylethyl)chromone skeleton. Herein we report a straightforward 3-step preparation of five naturally occurring 2-(2-phenylethyl)chromones utilizing the Claisen condensation as the key step. PMID:23935224

  13. Synthesis of 3,3'-carbonyl-bis(chromones) and their activity as mammalian alkaline phosphatase inhibitors.

    Science.gov (United States)

    Miliutina, Mariia; Ejaz, Syeda Abida; Iaroshenko, Viktor O; Villinger, Alexander; Iqbal, Jamshed; Langer, Peter

    2016-01-14

    Hitherto unknown 3,3'-carbonyl-bis(chromones) 8, dimeric chromones bridged by a carbonyl group, were prepared by reaction of chromone-3-carboxylic acid chloride with 3-(dimethylamino)-1- (2-hydroxyphenyl)-2-propen-1-ones 9. The method is generally applicable for the synthesis of novel symmetrical or non-symmetrical products which were found to inhibit mammalian alkaline phosphatases.

  14. Antiviral chromones from the stem of Cassia siamea.

    Science.gov (United States)

    Hu, Qiu-Fen; Zhou, Bin; Gao, Xue-Mei; Yang, Li-Ying; Shu, Li-Dan; Shen, Yanqiong; Li, Gan-Peng; Che, Chun-Tao; Yang, Guang-Yu

    2012-11-26

    Seven new chromones, siamchromones A-G (1-7), and 12 known chromones (8-19) were isolated from the stems of Cassia siamea. Compounds 1-19 were evaluated for their antitobacco mosaic virus (anti-TMV) and anti-HIV-1 activities. Compound 6 showed antitobacco mosaic virus (anti-TMV) activity with an inhibition rate of 35.3% and IC50 value of 31.2 μM, which is higher than that of the positive control, ningnamycin. Compounds 1, 10, 13, and 16 showed anti-TMV activities with inhibition rates above 10%. Compounds 4, 6, 13, and 19 showed anti-HIV-1 activities with therapeutic index values above 50.

  15. A New Chromone Derivative from Stellera chamaejasme L.

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new chromone derivative, 3-[1- (2, 4, 6-trihydroxyphenyl) 3-di-(4-hydroxyphenyl) 1-propanone-2-yl] 5,7-dihydroxy-8-di(4-hydroxyphenyl)methyl-4H-1-benzopyran-4-one, named as isomohsenone was isolated from the roots of Stellera chamaejasme L. together with known chamaechromone. Its structure was determined by the analysis of MS and NMR data, especially 2D NMR spectra.

  16. Studies on the antioxidant activities of some new chromone compounds.

    Science.gov (United States)

    Kładna, Aleksandra; Berczyński, Paweł; Piechowska, Teresa; Kruk, Irena; Aboul-Enein, Hassan Y; Ceylan-Unlusoy, Meltem; Verspohl, Eugen J; Ertan, Rahmiye

    2014-11-01

    Recent reviews evidence that the naturally occurring compounds containing the chromone skeleton exhibit antiradical activities, providing protection against oxidative stress. The antioxidant activities of 13 new synthesized chromonyl-2,4-thiazolidinediones, chromonyl-2,4-imidazolidinediones and chromonyl-2-thioxoimidzolidine-4-ones were evaluated using in vitro antioxidant assays, including superoxide anion radical (O2(-•)), hydroxyl radical (HO(•)), 2,2-diphenyl-1-picryl-hydrazyl free radical (DPPH(•)) scavenging capacity and total antioxidant capacity ferric ion reducing activity. Superoxide anion radical was produced using potassium superoxide/18-crown-6-ether dissolved in dimethylsulfoxide, and the Fenton-like reaction (Fe(II) + H2O2) was a generator of hydroxyl radicals. Chemiluminescence, spectrophotometry, electron paramagnetic resonance (EPR) and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as the spin trap were the measurement techniques. The results showed that the majority of the chromone derivatives tested showed a strong scavenging effect towards free radicals, similar to the chemiluminescence reaction with superoxide anion radical with a high activity, inhibition of the DMPO-OOH radical EPR signal (24-58%), the DMPO-OH radical EPR signal (4-75%) and DPPH radical EPR signal (6-100%) at 1 mmol/L. Several of the examined compounds exhibited the high reduction potentials. The results obtained show that the new synthesized chromone derivatives may directly scavenger reactive oxygen species and thus may play a protective role against oxidative damage. Copyright © 2014 John Wiley & Sons, Ltd.

  17. Physiochemical, Optical and Biological Activity of Chitosan-Chromone Derivative for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Joonseok Koh

    2012-05-01

    Full Text Available This paper describes the physiochemical, optical and biological activity of chitosan-chromone derivative. The chitosan-chromone derivative gels were prepared by reacting chitosan with chromone-3-carbaldehyde, followed by solvent exchange, filtration and drying by evaporation. The identity of Schiff base was confirmed by UV-Vis absorption spectroscopy and Fourier-transform infrared (FTIR spectroscopy. The chitosan-chromone derivative was evaluated by X-ray diffraction (XRD, thermogravimetric analysis (TGA, differential scanning calorimetry (DSC, scanning electron microscopy (SEM, photoluminescence (PL and circular dichroism (CD. The CD spectrum showed the chitosan-chromone derivative had a secondary helical structure. Microbiological screening results demonstrated the chitosan-chromone derivative had antimicrobial activity against Escherichia coli bacteria. The chitosan-chromone derivative did not have any adverse effect on the cellular proliferation of mouse embryonic fibroblasts (MEF and did not lead to cellular toxicity in MEFs. These results suggest that the chitosan-chromone derivative gels may open a new perspective in biomedical applications.

  18. Physiochemical, optical and biological activity of chitosan-chromone derivative for biomedical applications.

    Science.gov (United States)

    Kumar, Santosh; Koh, Joonseok

    2012-01-01

    This paper describes the physiochemical, optical and biological activity of chitosan-chromone derivative. The chitosan-chromone derivative gels were prepared by reacting chitosan with chromone-3-carbaldehyde, followed by solvent exchange, filtration and drying by evaporation. The identity of Schiff base was confirmed by UV-Vis absorption spectroscopy and Fourier-transform infrared (FTIR) spectroscopy. The chitosan-chromone derivative was evaluated by X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), photoluminescence (PL) and circular dichroism (CD). The CD spectrum showed the chitosan-chromone derivative had a secondary helical structure. Microbiological screening results demonstrated the chitosan-chromone derivative had antimicrobial activity against Escherichia coli bacteria. The chitosan-chromone derivative did not have any adverse effect on the cellular proliferation of mouse embryonic fibroblasts (MEF) and did not lead to cellular toxicity in MEFs. These results suggest that the chitosan-chromone derivative gels may open a new perspective in biomedical applications.

  19. Dynamic states of swimming bacteria in a nematic liquid crystal cell with homeotropic alignment

    Science.gov (United States)

    Zhou, Shuang; Tovkach, Oleh; Golovaty, Dmitry; Sokolov, Andrey; Aranson, Igor S.; Lavrentovich, Oleg D.

    2017-05-01

    Flagellated bacteria such as Escherichia coli and Bacillus subtilis exhibit effective mechanisms for swimming in fluids and exploring the surrounding environment. In isotropic fluids such as water, the bacteria change swimming direction through the run-and-tumble process. Lyotropic chromonic liquid crystals (LCLCs) have been introduced recently as an anisotropic environment in which the direction of preferred orientation, the director, guides the bacterial trajectories. In this work, we describe the behavior of bacteria B. subtilis in a homeotropic LCLC geometry, in which the director is perpendicular to the bounding plates of a shallow cell. We demonstrate that the bacteria are capable of overcoming the stabilizing elastic forces of the LCLC and swim perpendicularly to the imposed director (and parallel to the bounding plates). The effect is explained by a finite surface anchoring of the director at the bacterial body; the role of surface anchoring is analyzed by numerical simulations of a rod realigning in an otherwise uniform director field. Shear flows produced by a swimming bacterium cause director distortions around its body, as evidenced both by experiments and numerical simulations. These distortions contribute to a repulsive force that keeps the swimming bacterium at a distance of a few micrometers away from the bounding plates. The homeotropic alignment of the director imposes two different scenarios of bacterial tumbling: one with an 180° reversal of the horizontal velocity and the other with the realignment of the bacterium by two consecutive 90° turns. In the second case, the angle between the bacterial body and the imposed director changes from 90° to 0° and then back to 90° the new direction of swimming does not correlate with the previous swimming direction.

  20. An efficient approach to functionalized benzo[a]xanthones through reactions of 2-methyl-3-(1-alkynyl)chromones with electron-deficient chromone-fused dienes.

    Science.gov (United States)

    Gong, Jian; Xie, Fuchun; Chen, Hong; Hu, Youhong

    2010-09-03

    An efficient tandem process was developed to synthesize diversified benzo[a]xanthones from 2-methyl-3-(1-alkynyl)chromones with electron-deficient chromone-fused dienes. This unusual reaction, involving multiple steps and not requiring the use of transition metal catalysts or an inert atmosphere, results in the formation of three new C-C bonds and one C-O bond.

  1. Inhibition of monoamine oxidase by selected C6-substituted chromone derivatives.

    Science.gov (United States)

    Legoabe, Lesetja J; Petzer, Anél; Petzer, Jacobus P

    2012-03-01

    Chromone has been reported to be a useful scaffold for the design of monoamine oxidase (MAO) inhibitors. In an attempt to discover highly potent MAO inhibitors and to contribute to the known structure-activity relationships (SAR) of MAO inhibition by chromones, in the present study, we have synthesized a series of chromone derivatives substituted at C6 with a variety of alkyloxy substituents, and evaluated the resulting compounds as inhibitors of recombinant human MAO-A and -B. The results document that the C6-substituted chromones are potent reversible MAO-B inhibitors with IC(50) values in the low nM range (2-76 nM). The chromones were also found to bind reversibly to MAO-A, but with lower affinities compared to MAO-B. It may therefore be concluded that C6-substituted chromones are highly potent MAO-B selective inhibitors and promising lead compounds for the development of therapy for neurodegenerative disorders such as Parkinson's disease. The results of this study are discussed with reference to possible binding orientations of a selected C6-substituted chromone in the active site cavities of MAO-A and -B. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  2. Chromone, a privileged scaffold for the development of monoamine oxidase inhibitors.

    Science.gov (United States)

    Gaspar, Alexandra; Silva, Tiago; Yáñez, Matilde; Vina, Dolores; Orallo, Franscisco; Ortuso, Francesco; Uriarte, Eugenio; Alcaro, Stefano; Borges, Fernanda

    2011-07-28

    Two series of novel chromone derivatives were synthesized and investigated for their ability to inhibit the activity of monoamine oxidase. The SAR data indicate that chromone derivatives with substituents in position 3 of γ-pyrone nucleus act preferably as MAO-B inhibitors, with IC(50) values in the nanomolar to micromolar range. Almost all chromone 3-carboxamides display selectivity toward MAO-B. Identical substitutions on position 2 of γ-pyrone nucleus result in complete loss of activity in both isoforms (chromones 2-12 except 3 and 5). Notably, chromone (19) exhibits an MAO-B IC(50) of 63 nM, greater than 1000-fold selectivity over MAO-A, and behaves as a quasi-reversible inhibitor. Docking experiments onto the MAO binding of the most active compound highlight different interaction patterns among the isoforms A and B. The differential analysis of the solvation effects among the chromone isomers gave additional insight about the superior outline of the 3-substituted chromone derivatives.

  3. Chromone derivatives from a sponge-derived strain of the fungus Corynespora cassiicola.

    Science.gov (United States)

    Zhao, Dong-Lin; Shao, Chang-Lun; Gan, Li-She; Wang, Mei; Wang, Chang-Yun

    2015-02-27

    Twelve new chromone derivatives, corynechromones A-L (1-12), were isolated from the sponge-derived fungus Corynespora cassiicola XS-200900I7. Among them, 1/2, 3/4, 5/6, and 7/8 were pairs of epimers. The planar structures were determined by extensive NMR spectroscopic data. The absolute configurations of 1-10 were assigned by the modified Mosher's method and TDDFT ECD calculations together with comparison of their CD spectra. These are the first chromone derivatives reported from the genus Corynespora. A possible rule to determine the absolute configurations at C-2 in chromone derivatives by CD was proposed.

  4. Triglyceride accumulation inhibitory effects of new chromone glycosides from Drynaria fortunei.

    Science.gov (United States)

    Han, Lifeng; Zheng, Fang; Zhang, Yi; Liu, Erwei; Li, Wei; Xia, Minghui; Wang, Tao; Gao, Xiumei

    2015-01-01

    Two new chromone glycosides, drynachromosides C (1) and D (2), along with five known chromones (3-7), were isolated from the rhizomes of Drynaria fortunei. The structures of the two new compounds were elucidated on the basis of physico-chemical property and spectroscopic data. Triglyceride (TG) accumulation inhibitory effects of the obtained chromones on 3T3-L1 cells were investigated. The results showed that 1, 2 and 5 exhibited inhibitory activity on TG accumulation. Effects of compounds 1 and 2 on mRNA expression of PPARγ, C/EBPα and aP2 in 3T3-L1 cells were also investigated.

  5. Chromone-2- and -3-carboxylic acids inhibit differently monoamine oxidases A and B.

    Science.gov (United States)

    Alcaro, Stefano; Gaspar, Alexandra; Ortuso, Francesco; Milhazes, Nuno; Orallo, Francisco; Uriarte, Eugenio; Yáñez, Matilde; Borges, Fernanda

    2010-05-01

    Chromone carboxylic acids were evaluated as human monoamine oxidase A and B (hMAO-A and hMAO-B) inhibitors. The biological data indicated that only chromone-3-carboxylic acid is a potent hMAO-B inhibitor, with a high degree of selectivity for hMAO-B compared to hMAO-A. Conversely the chromone-2-carboxylic acid resulted almost inactive against both MAO isoforms. Docking experiments were performed to elucidate the reasons of the different MAO IC(50) data and to explain the absence of activity versus selectivity, respectively. 2010 Elsevier Ltd. All rights reserved.

  6. Ring transformation of chromone-3-carboxamide under nucleophilic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Ibrahim, Magdy A., E-mail: magdy_ahmed1977@yahoo.com [Department of Chemistry, Faculty of Education, Ain Shams University, Cairo(Egypt)

    2013-11-15

    The chemical reactivity of chromone-3-carboxamide was studied towards a series of nitrogen and carbon nucleophiles. Treatment of carboxamide with some primary amines gave chromane-2,4-diones. Condensation of carboxamide with hydrazine hydrate, phenyl hydrazine and hydroxylamine hydrochloride afforded chromenopyrazoles and chromenoisoxazole, respectively. Reaction of carboxamide with guanidine hydrochloride, cyanoguanidine and thiourea resulted in ring transformation producing chromenopyridines. The chemical behavior of carboxamide was also studied towards ethylenediamine, o-phenylenediamine, 2-aminophenol and 2-aminothiophenol. A variety of products were isolated from the reaction of carboxamide with some carbon nucleophiles. (author)

  7. New chromone and triglyceride from Cucumis melo seeds.

    Science.gov (United States)

    Ibrahim, Sabrin R M

    2014-02-01

    Re-investigation of the MeOH extract of the seeds of Cucumis melo L. var. reticulatus (Cucurbitaceae) led to the isolation of a new chromone derivative (5,7- dihydroxy-2-[2-(3-methoxy-4-hydroxyphenyl)ethyl]chromone (5) and a triglyceride (1,3-di-(6Z,9Z)-docosa-6,9-dienoyl-2-(6Z) hexacos-6-enoylglycerol (1), together with three known compounds; alpha-spinasterol (2), stigmasta-7,22,25-trien-3-ol (3), and D:B-friedoolean-5-ene-3-beta-ol (4), are reported from this species for the first time. Their structures were determined by extensive 1D (1H, 13C, and DEPT) and 2D (1H-1H COSY, HMQC, and HMBC) NMR and mass spectral measurements. Compound 5 displayed significant cytotoxic activity against L5178Y cells, with an ED50 of 5 microM. The MeOH extract and 5 showed antioxidant activity using the DPPH assay.

  8. Antioxidant Properties and Oxidative Transformation of Different Chromone Derivatives

    Directory of Open Access Journals (Sweden)

    Evelin Csepanyi

    2017-04-01

    Full Text Available Nowadays, there is an increase in the application of natural products for the prevention of different disorders or adjuvant substances next to pharmacological treatment. Phytochemicals include different chromone derivatives, which possess a wide spectrum of biological activity. The aim of the present study was the investigation of the antioxidant activity, cytotoxicity and oxidative transformation of nine chromone derivatives. First, we investigated the radical scavenging activity (ABTS, the oxygen radical absorption capacity (ORAC and the ferric reducing antioxidant power (FRAP of the investigated molecules. The cytotoxic effects of the compounds were tested on H9c2 cell cultures by the MTT assay. Each compound showed a significant ORAC value compared to the reference. However, the compound 865 possess significantly higher FRAP and ABTS activity in comparison with the reference and other tested molecules, respectively. Based on these assays, the compound 865 was selected for further analysis. In these experiments, we investigated the oxidative metabolism of the compound in vitro. The molecule was oxidized by the Fenton reaction, artificial porphyrin and electrochemistry; then, the formed products were identified by mass spectrometry. Four possible metabolites were detected. The results revealed the compound 865 to possess good antioxidant properties and to be stable metabolically; hence, it is worth investigating its effects in vivo.

  9. Antioxidant Properties and Oxidative Transformation of Different Chromone Derivatives.

    Science.gov (United States)

    Csepanyi, Evelin; Szabados-Furjesi, Peter; Kiss-Szikszai, Attila; Frensemeier, Lisa M; Karst, Uwe; Lekli, Istvan; Haines, David D; Tosaki, Arpad; Bak, Istvan

    2017-04-06

    Nowadays, there is an increase in the application of natural products for the prevention of different disorders or adjuvant substances next to pharmacological treatment. Phytochemicals include different chromone derivatives, which possess a wide spectrum of biological activity. The aim of the present study was the investigation of the antioxidant activity, cytotoxicity and oxidative transformation of nine chromone derivatives. First, we investigated the radical scavenging activity (ABTS), the oxygen radical absorption capacity (ORAC) and the ferric reducing antioxidant power (FRAP) of the investigated molecules. The cytotoxic effects of the compounds were tested on H9c2 cell cultures by the MTT assay. Each compound showed a significant ORAC value compared to the reference. However, the compound 865 possess significantly higher FRAP and ABTS activity in comparison with the reference and other tested molecules, respectively. Based on these assays, the compound 865 was selected for further analysis. In these experiments, we investigated the oxidative metabolism of the compound in vitro. The molecule was oxidized by the Fenton reaction, artificial porphyrin and electrochemistry; then, the formed products were identified by mass spectrometry. Four possible metabolites were detected. The results revealed the compound 865 to possess good antioxidant properties and to be stable metabolically; hence, it is worth investigating its effects in vivo.

  10. Chromones: A Promising Ring System for New Anti-inflammatory Drugs.

    Science.gov (United States)

    Silva, Carlos F M; Pinto, Diana C G A; Silva, Artur M S

    2016-10-19

    The quest for safer anti-inflammatory drugs is still the focus of several medicinal chemistry programs. Chromones (4H-chromen-4-ones) are a group of naturally occurring compounds ubiquitous in plants, and the chromone core has proven to be a privileged scaffold in medicinal chemistry. Herein we provide an overview of the relevance of chromones as anti-inflammatory agents, specifically as inhibitors of cyclooxygenase (COX), 5-lipoxygenase (5-LOX), interleukin-5 (IL-5), and nitric oxide ((.) NO) production. Numerous structure-activity relationships and mechanisms of action are discussed. This review is therefore intended to provide a foundation for the design and synthesis of novel chromone-based compound libraries for further development into safer and more efficient anti-inflammatory agents. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Cucumin S, a new phenylethyl chromone from Cucumis melo var. reticulatus seeds

    Directory of Open Access Journals (Sweden)

    Sabrin R.M. Ibrahim

    2015-10-01

    Full Text Available ABSTRACTA new phenylethyl chromenone, cucumin S [(R-5,7-dihydroxy-2-[1-hydroxy-2-(4-hydroxy-3-methoxyphenylethyl]chromone] (1, along with five known compounds: 5,7-dihydroxy-2-[2-(4-hydroxyphenylethyl]chromone (2, 5,7-dihydroxy-2-[2-(3,4-dihydroxyphenylethyl]chromone (3, luteolin (4, quercetin (5, and 7-glucosyloxy-5-hydroxy-2-[2-(4-hydroxyphenylethyl]chromone (6 were isolated from the EtOAc fraction of Cucumis melo var. reticulatus Ser., Cucurbitaceae, seeds. Their structures were determined by spectroscopic means (1D and 2D NMR, as well as HRESIMS, optical rotation measurement, and comparison with literature data. The isolated compounds 1–6 were assessed for their antioxidant activity using DPPH assay. Compounds 3, 4, and 5 showed potent activities compared to propyl gallate at concentration 100 µM.

  12. Natural occurring 2-(2-phenylethyl) chromones, structure elucidation and biological activities.

    Science.gov (United States)

    Ibrahim, Sabrin R M; Mohamed, Gamal A

    2015-01-01

    2-(2-Phenylethyl) chromone (PEC), an uncommon class of chromones, possesses a phenylethyl substituent at the C2 position. They have been isolated from a few plant species. They have promising biological activities such as neuro-protective, cytotoxic, acetylcholinesterase inhibitory, antibacterial and anti-inflammatory. This review focuses on the naturally occurring PEC derivatives, their sources, physical and spectral data, as well as biological activities.

  13. Cystochromones, Unusual Chromone-Containing Polyketides from the Myxobacterium Cystobacter sp. MCy9104.

    Science.gov (United States)

    Nadmid, Suvd; Plaza, Alberto; Garcia, Ronald; Müller, Rolf

    2015-08-28

    Seven new chromone-containing polyketides, termed cystochromones A-G, were isolated from the myxobacterial strain Cystobacter sp. MCy9104. Their structures were elucidated using comprehensive NMR spectroscopy and HR-MS/MS. Cystochromones bear a pentadecyl moiety unusually attached at C-5 of the chromone ring. Moreover, isotope-labeled substrate feeding experiments and NMR analysis suggested a hybrid iso-fatty acid and polyketide synthase biosynthetic pathway for these secondary metabolites.

  14. Fluorescence properties of light-sensitive chromones used in archival polymer recording media

    Science.gov (United States)

    Martynov, I. Yu.; Barachevsky, V. A.; Ayt, A. O.; Kobeleva, O. I.; Valova, T. M.; Levchenko, K. S.; Yarovenko, V. N.; Krayushkin, M. M.

    2014-11-01

    The fluorescence properties of compounds formed upon irreversible photochemical transformation of some chromone derivatives in toluene were studied. At the first time, the quantum yields of the photoproducts were measured. The relationship between the fluorescence properties and the structure of these photoproducts was elucidated. It was shown that the properties of some chromones make them suitable for the design of light-sensitive recording media for optical discs with non-destructive fluorescence readout of optical information.

  15. A new 2-(2-phenylethyl)chromone derivative in Chinese agarwood 'Qi-Nan' from Aquilaria sinensis.

    Science.gov (United States)

    Yang, De-Lan; Wang, Hao; Guo, Zhi-Kai; Dong, Wen-Hua; Mei, Wen-Li; Dai, Hao-Fu

    2014-01-01

    Phytochemical analysis of the high quality Chinese agarwood 'Qi-Nan' originating from Aquilaria sinensis (Lour.) Glig led to the isolation of a new 2-(2-phenylethyl)chromone derivative, qinanones G (1), and four known 2-(2-phenylethyl)chromones (2-5). Their structures were elucidated by spectroscopic techniques (UV, IR, 1D and 2D NMR) and MS analyses. The NMR data of chromones 1-3 were first reported, and chromones 2 and 3 showed weak inhibitory activity against acetylcholinesterase.

  16. Insensitivity of volume-sensitive chloride currents to chromones in human airway epithelial cells

    Science.gov (United States)

    Zegarra-Moran, Olga; Lantero, Sabina; Sacco, Oliviero; Rossi, Giovanni A; Galietta, Luis J V

    1998-01-01

    Chromones (sodium cromoglycate and sodium nedocromil) block cell swelling-activated Cl− channels in NIH-3T3 fibroblasts and endothelial cells. This has led to hypothesize that cell volume regulation might be involved in asthma pathogenesis.Using whole-cell patch-clamp experiments, we studied the effect of chromones on volume-sensitive Cl− currents in transformed human tracheal epithelial cells (9HTEo-) and in primary cultures of human bronchial epithelial cells (BE).Cl− currents activated by hypotonic shock were poorly blocked by extracellular nedocromil or cromoglycate. The block was voltage-dependent since it was observed only at positive membrane potentials. At the concentration of 5 mM, the current inhibition by both chromones at +80 mV was about 40% for 9HTEo- and only 20% for BE.Intracellular application of chromones elicited a voltage-independent inhibition in 9HTEo- cells. Under this condition, volume-sensitive Cl− currents were reduced at all membrane potentials (60 and 45% inhibition by 2 mM nedocromil and cromoglycate respectively). In contrast intracellular chromones were ineffective in BE cells.The relative refractoriness to chromones, in contrast with the high sensitivity shown by other Cl− channels, suggests that the epithelial volume-sensitive Cl− channel is not involved in asthma. PMID:9863671

  17. Discovery of novel A3 adenosine receptor ligands based on chromone scaffold.

    Science.gov (United States)

    Gaspar, Alexandra; Reis, Joana; Kachler, Sonja; Paoletta, Silvia; Uriarte, Eugenio; Klotz, Karl-Norbert; Moro, Stefano; Borges, Fernanda

    2012-07-01

    A project focused on the discovery of new chemical entities (NCEs) as AR ligands that incorporate a benzo-γ-pyrone [(4H)-1-benzopyran-4-one] substructure has been developed. Accordingly, two series of novel chromone carboxamides placed at positions C2 (compounds 2-13) and C3 (compounds 15-26) of the γ-pyrone ring were synthesized using chromone carboxylic acids (compounds 1 or 14) as starting materials. From this study and on the basis of the obtained structure-activity relationships it was concluded that the chromone carboxamide scaffold represent a novel class of AR ligands. The most remarkable chromones were compounds 21 and 26 that present a better affinity for A3AR (Ki = 3680 nM and Ki = 3750 nM, respectively). Receptor-driven molecular modeling studies provide information on the binding/selectivity data of the chromone. The data so far acquired are instrumental for future optimization of chromone carboxamide as a selective A3AR antagonist. Copyright © 2012 Elsevier Inc. All rights reserved.

  18. 2-(2-phenylethyl)chromone derivatives from Chinese agarwood induced by artificial holing.

    Science.gov (United States)

    Li, Wei; Cai, Cai-Hong; Dong, Wen-Hua; Guo, Zhi-Kai; Wang, Hao; Mei, Wen-Li; Dai, Hao-Fu

    2014-10-01

    Three new 2-(2-phenylethyl)chromone derivatives (1-3), together with thirteen known ones (4-16), were isolated from the EtOAc extract of Chinese agarwood induced by artificial holing, originating from Aquilaria sinensis (Lour.) Gilg (Thymelaeaceae). The chemical structures of the new compounds were identified by spectroscopic techniques (UV, IR, MS, 1D and 2D NMR). Compounds 1, 6, 15 and 16 exhibited inhibitory effects on Staphylococcus aureus, and compounds 15 and 16 showed inhibitory effects on Ralstonia solanacearum. Compounds 1-3, 7, 9, 11, 12, 15 and 16 exhibited acetylcholinesterase inhibitory activity. A possible biogenetic pathway of compounds 1-16 was proposed to show the relationships between diepoxy-tetrahydro-2-(2-phenylethyl)chromones, epoxy-tetrahydro-2-(2-phenylethyl) chromones, tetrahydro-2-(2-phenylethyl)chromones, and 2-(2-phenylethyl)chromones of the flidersia type, the four main types of 2-(2-phenylethyl)chromones found in agarwood, on the basis of their appearances in different stage of agarwood formation. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. A new chromone from Hymenocallis littoralis Salisb. (Amaryllidaceae).

    Science.gov (United States)

    Anh, Dinh Thi Phuong; Duong, Tran Bach; Hoang, Vu Dinh

    2014-01-01

    A new chromone, 5,7-dihydroxy-6,8-dimethoxy-2-methyl-4H-chromen-4-one (1), together with seven known compounds, 5,7-dihydroxy-6-methoxy-2-methyl-4H-chromen-4-one (pisonin B) (2), 5,7-dihydroxy-2-methyl-4H-chromen-4-one (noreugenin) (3), 5-hydroxy-7-methoxy-2-methyl-4H-chromen-4-one (eugenin) (4), (2S)-7,4'-dihydroxyflavan (5), 3',7-dihydroxy-4'-methoxy-8-methylflavan (6), 3',7-dihydroxy-4'-methoxyflavan (7) and 6,8-dimethyl-5,7,4'-trihydroxyflavanone (( - )-farrerol) (8), were isolated from Hymenocallis littoralis Salisb. (Amaryllidaceae) growing in Vietnam. Their structures were determined based on spectroscopic and physicochemical analyses.

  20. Characterization and determination of 2-(2-phenylethyl)chromones in agarwood by GC-MS.

    Science.gov (United States)

    Mei, Wen-Li; Yang, De-Lan; Wang, Hao; Yang, Jin-Ling; Zeng, Yan-Bo; Guo, Zhi-Kai; Dong, Wen-Hua; Li, Wei; Dai, Hao-Fu

    2013-10-08

    Agarwood is the fragrant resinous heartwood obtained from certain trees in the genus Aquilaria belonging to the family Thymelaeaceae. 2-(2-Phenylethyl)chromones and characteristic sesquiterpenes are the main classes of aromatic compounds isolated from agarwood. Although there are many sesquiterpenes, relatively few 2-(2-phenylethyl)chromones have been determined in agarwood by GC-MS. After analysis of the MS spectra of eighteen 2-(2-phenylethyl)chromone derivatives isolated from agarwood and identified by NMR spectroscopy, together with the reported MS data and characteristic of structures of 2-(2-phenylethyl)chromones, the MS characterization, fragmentation patterns and characteristic fragment peaks for the compounds were deduced and a table summarizing MS characterization of 2-(2-phenylethyl)chromones in agarwood is presented. All the 2-(2-phenylethyl)chromones previously reported in agarwood are substituted by methoxy or/and hydroxy groups, except for one compound. Due to the fact they all possess the same basic skeleton (molecular weight: 250) and similar substituent groups (methoxy or hydroxy groups), a formula (30m + 16n = MW - 250) is provided to calculate the number of methoxy (m) or hydroxy (n) groups according to molecular ion peak or molecular weight (MW). We deduced that the characteristic fragmentation behaviors of the 2-(2-phenylethyl)chromones are the cleavages of the CH₂-CH₂ bond between chromone moiety and phenyl moiety. Thus, characteristic fragment ions, such as m/z 91 [C₇H₇], 107 [C₇H₆+OH], 121 [C₇H₆+OCH₃], 137 [C₇H5+OH+OCH₃] are formed by different substituted benzyl moieties, while characteristic fragment ions such as m/z 160 [C₁₀H₈O₂], 176 [C₁₀H₇O₂+OH], 190 [C₁₀H₇O₂+OCH₃], 220 [C₁₀H₆O₂+OCH₃×2] are formed by different substituted chromone moieties. Furthermore, rules regarding to the relationship between the positions of hydroxy or methoxy groups and the relative abundances of benzyl

  1. Anisotropic surface melting in lyotropic cubic crystals. Part 1: Pn3m/L1 interface, poor faceting.

    Science.gov (United States)

    Grenier, J; Plötzing, T; Rohe, D; Pieranski, P

    2006-02-01

    From experiments with ice or metal crystals, in the vicinity of their crystal/liquid/vapor triple points, it is known that melting of crystals starts on their surfaces and is anisotropic. It is shown here by direct observations under an optical microscope that this anisotropic surface melting phenomenon occurs also in lyotropic systems. In the case of C12EO2/water mixture, it takes place in the vicinity of the peritectic Pn3m/L3/L1 triple point. Above the peritectic triple point, where the Pn3m and L1 phases coexist in the bulk, the surface of a Pn3m-in-L1 crystal is composed of (111)-type facets surrounded by rough surfaces. The angular junction suggests that rough surfaces are wet by a L3-like layer while facets stay "dry". This is analogous to the pre-melting at rough surfaces in solid crystals. Upon cooling below the peritectic triple point, where L3 and L1 phases coexist in the bulk, a thick layer of the L3 phase grows from the pre-melted, rough Pn3m/L1 interface. Simultaneously, facets stay dry and their radius decreases. In this tri-phasic configuration, stable in a narrow temperature range, the L3/L1 and L3/Pn3m interfaces have shapes of constant mean curvature surfaces having common borders: edges of facets.

  2. Synthesis and pharmacological activities of non-flavonoid chromones: a patent review (from 2005 to 2015).

    Science.gov (United States)

    Matos, Maria João; Vazquez-Rodriguez, Saleta; Uriarte, Eugenio; Santana, Lourdes; Borges, Fernanda

    2015-01-01

    Chromones are one of the major classes of naturally occurring compounds. Their chemistry has been widely explored and extensively reviewed. The following review intends to give a broad overview of the patented chromones. Particular attention has been given to their synthesis, uses and applications in last 10 years. The authors provide an overview of the recent scientific reports describing the obtaining and study of new chromones. The review emphasizes the rationale behind natural sources, synthesis, biological activities and structure-activity relationships of the new chromone derivatives. The article is based on the literature published from 2005 to 2015 related to the development of this family of compounds. The patents presented in this review have been collected from multiple electronic databases including SciFinder, Espacenet and Mendeley. Although a great number of chromones have been published in bibliographic sources in the last years, there is little innovation in the synthetic methodologies. Some natural sources and isolation techniques were described. Different pharmacological applications have also been claimed. Two of the most studied applications have been the use of these compounds as therapeutic agents for cancer and skin diseases. Some safety requirements need to be developed in order to find new chemical entities as new drugs.

  3. Chromones and their derivatives as radical scavengers: a remedy for cell impairment.

    Science.gov (United States)

    Yadav, Preeti; Parshad, Badri; Manchanda, Priyanka; Sharma, Sunil K

    2014-01-01

    Chromones (1-benzopyran-4-ones) are natural occurring compounds present in representative amounts in a normal human diet and are associated with interesting physiological activities such as antiinflammatory, antidiabetic, antitumor, anticancer etc. These biological activities are thought to be related to the antioxidant properties of chromones i.e. to neutralize active oxygen and to cut off free radicals processes that can delay or inhibit cell impairment which leads to various diseases. In this review, we have summarized the literature reports published in about 70 research articles during the period January 2004 to March 2014 on more than 400 naturally as well as the synthetically derived chromone derivatives having antioxidant potential. The literature reports suggest that the double bond, a carbonyl group of chromone and 3´,4´-dihydroxy group (catechol) in ring B along with the C-3 and C-5 hydroxyl groups are important for radical scavenging activity. In turn, a decrease in the radical scavenging potential has been observed upon methylation / glycosylation of the hydroxyl groups on chromone nucleus.

  4. Dynamics of freely suspended lyotropic films. I. An inelastic light scattering study of thermal surface fluctuations

    Science.gov (United States)

    Young, Charles Y.; Clark, Noel A.

    1981-04-01

    We have studied the spectrum and intensity of light scattered by thermal surface displacement fluctuations on freely suspended lyotropic films. Films consisted of a liquid core and surface soap layers and were drawn from solution containing water, glycerol, NaCl, and the ionic surfactant hexadecyltrimethyl ammonium bromide (HTAB). Two modes were observed: a propagating undulation mode in which the film surfaces move together and a damped peristaltic mode having oppositely moving surface soap layers. Dispersion relations for these modes, obtained from the dependence of the scattered light intensity correlation function on film thickness h and wave vector k, confirm the macroscopic hydrodynamic description of film motion. In particular, the overdamped peristaltic mode is shown to involve Poiseuille flow of the fluid core with the flow velocity zero within 2 Å of the surfactant-solution interface, indicating no significant slip or rigid interfacial water layer. No evidence of dispersion in the effective viscosity of the fluid core h(k,w) over the range 0

  5. 2015 Liquid Crystals Gordon Research Conference and Gordon Research Seminar

    Science.gov (United States)

    2015-10-20

    physics, chemistry , and biology of systems that possess liquid crystallinity will be emphasized. The conference will bring together an outstanding group...supramolecular chemistry and multifunctional materials, (iii) liquid crystalline glasses and metastable phases, (iv) liquid crystallinity in biological...USA) "Templating Polymers with Lyotropic Liquid Crystals via Photopolymerization Using a Gemini Surfactant " 11:55 am - 12:00 pm Discussion 12:00 pm

  6. 2-(2-Phenylethyl)chromone Derivatives of Agarwood Originating from Gyrinops salicifolia.

    Science.gov (United States)

    Shao, Hang; Mei, Wen-Li; Dong, Wen-Hua; Gai, Cui-Juan; Li, Wei; Zhu, Guo-Peng; Dai, Hao-Fu

    2016-10-03

    Three new2-(2-phenylethyl)chromone derivatives (1-3) and a new2-(2-phenylethenyl)chromone derivative (4), together with two known 2-(2-phenylethyl)chromone derivatives (5-6), were isolated from agarwood originating from Gyrinops salicifolia Ridl. The structures of compounds 1-4 were elucidated by comprehensive spectroscopic techniques (UV, IR, 1D and 2D-NMR) and MS analysis, as well as by comparison with the literature. Compounds 1, 2, and 5 showed moderate cytotoxicity against human tumor K562, BEL-7402, and SGC-7901 cell lines with IC50 values of 5.76 to 20.1 µM.

  7. Synthesis, in vitro evaluation, and docking studies of novel chromone derivatives as HIV-1 protease inhibitor

    Science.gov (United States)

    Ungwitayatorn, Jiraporn; Wiwat, Chanpen; Samee, Weerasak; Nunthanavanit, Patcharawee; Phosrithong, Narumol

    2011-08-01

    Novel chromone derivatives with a benzopyran-4-one scaffold have been prepared by the one-pot cyclization reaction. The in vitro inhibitory activity of these new compounds towards HIV-1 protease have been evaluated using stop time HPLC method as the preliminary screening. The most potent compound, 7,8-dihydroxy-2-(3'-trifluoromethyl phenyl)-3-(3″-trifluoromethylbenzoyl)chromone ( 32), showed IC 50 = 0.34 μM. The molecular docking study supported results from experimental activity testing and also provided structure-activity relationship of this series.

  8. SYNTHESIS AND ANTIMICROBIAL EVALUATION OF CHROMONES BEARING 1, 5-BENZO THIAZEPINYL MOIETY

    Directory of Open Access Journals (Sweden)

    R.V. Dengle* and R. N. Deshmukh

    2013-04-01

    Full Text Available ABSTRACT: 1, 5-Benzothazepinyl chromones were synthesized starting from 2, 4-diacyl phenol. The 2, 4-diacyl phenol was condensed with aryl aldehydes to obtain bis-chalcones1a-d. The bis-chalcones on cyclocondensation with equimolar amount of 2-aminothiophenol gave 1, 5-benzothiazepinyl chalcones2a-d. The chalcones on oxidative cyclisation in DMSO - I2 yielded the titled compounds3a-d. The microbial evaluation of the representative 1, 5-benzothiazepinyl chromones has also been performed.

  9. SYNTHESIS AND ANTIMICROBIAL EVALUATION OF CHROMONES BEARING 1, 5-BENZO THIAZEPINYL MOIETY

    OpenAIRE

    2013-01-01

    ABSTRACT: 1, 5-Benzothazepinyl chromones were synthesized starting from 2, 4-diacyl phenol. The 2, 4-diacyl phenol was condensed with aryl aldehydes to obtain bis-chalcones1a-d. The bis-chalcones on cyclocondensation with equimolar amount of 2-aminothiophenol gave 1, 5-benzothiazepinyl chalcones2a-d. The chalcones on oxidative cyclisation in DMSO - I2 yielded the titled compounds3a-d. The microbial evaluation of the representative 1, 5-benzothiazepinyl chromones has also been performed.

  10. Antioxidant lignans and chromone glycosides from Eurya japonica.

    Science.gov (United States)

    Yang Kuo, Li-Ming; Zhang, Li-Jie; Huang, Hung-Tse; Lin, Zhi-Hu; Liaw, Chia-Ching; Cheng, Hui-Ling; Lee, Kuo-Hsiung; Morris-Natschke, Susan L; Kuo, Yao-Haur; Ho, Hsiu-O

    2013-04-26

    Four new 8,8',7,2'-lignans, (+)-ovafolinin B-9'-O-β-d-glucopyranoside (1), (-)-ovafolinin B-9'-O-β-d-glucopyranoside (2), (+)-ovafolinin E-9'-O-β-d-glucopyranoside (3), and (-)-ovafolinin E-9'-O-β-d-glucopyranoside (4), two neolignans, eusiderin N (5) and (7S,8R)-3,5,5'-trimethoxy-4',7-epoxy-8,3'-neolignan-9,9'-diol-4-O-β-d-xylopyranoside (6), and two new chromone glycosides, 5,7-dihydroxy-4H-chromen-4-one-3-O-β-d-glucopyranoside (7) and 5,7-dihydroxy-4H-chromen-4-one-3-O-β-d-xylopyranoside (8), together with 25 known compounds, were isolated from the stems of Eurya japonica. Structural elucidation of compounds 1-8 was established by spectroscopic methods, especially 2D NMR techniques, electronic circular dichroism data, and comparison with reported data. The isolates were evaluated for antioxidant and anti-NO production activities. Compounds 1, 2, 12-20, and 29 (ED50 23.40 μM for 1) demonstrated potent antioxidant activity compared to the positive control α-tocopherol (ED50 27.21 μM). On the other hand, compounds 1, 2, 7-9, 12-20, and 32 showed only weak anti-NO production activity when compared to the positive control quercetin.

  11. A new 2-(2-phenylethyl)chromone glycoside in Chinese agarwood "Qi-Nan" from Aquilaria sinensis.

    Science.gov (United States)

    Shao, Hang; Mei, Wen-Li; Kong, Fan-Dong; Dong, Wen-Hua; Li, Wei; Zhu, Guo-Peng; Dai, Hao-Fu

    2017-01-01

    A new 2-(2-phenylethyl)chromone glycoside, 2-[2-(4-glucosyloxy-3-methoxyphenyl)ethyl]chromone (1), was isolated from the high-quality Chinese agarwood "Qi-Nan" originating from Aquilaria sinensis (Lour.) Glig. The structure including the absolute configuration of the sugar moiety was elucidated by spectroscopic techniques (UV, IR, 1D and 2D NMR), MS analysis, PMP-labeling HPLC analysis methods, as well as comparison with literature data. To the best of our knowledge, it is the first time that chromone glycoside was discovered in agarwood, or even in the whole Aquilaria plants.

  12. Rational design, synthesis and evaluation of chromone-indole and chromone-pyrazole based conjugates: identification of a lead for anti-inflammatory drug.

    Science.gov (United States)

    Shaveta; Singh, Amrinder; Kaur, Matinder; Sharma, Surbhi; Bhatti, Rajbir; Singh, Palwinder

    2014-04-22

    Conjugates of chromone-indole and chromone-pyrazole were screened for cyclooxygenase-2 (COX-2), cyclooxygenase-1 (COX-1) and 5-lipoxygenase (5-LOX) inhibitory activities. Compounds 8 and 9 were identified as preferred inhibitors of COX-2 over the other two enzymes. Their IC50 for COX-2 was 29 nM and 20 nM, respectively and selectivity indices (SI) for COX-2 over COX-1 was 46 and 337. NMR, mass spectral studies and molecular modelling also indicated preferential interactions of compounds 8 and 9 with COX-2. Tested on albino mice against capsaicin induced algesia, compound 8 exhibited analgesic potential comparable to diclofenac. In addition to the biological profile, the desirable physico-chemical properties of these compounds make them promising leads for anti-inflammatory drugs.

  13. Preussianone, a New Flavanone-Chromone Biflavonoid from Garcinia preussii Engl.

    Directory of Open Access Journals (Sweden)

    Gerhard Bringmann

    2012-05-01

    Full Text Available A new flavanone-chromone biflavonoid, preussianone (1, has been isolated from the leaves of Garcinia preussii, along with four known biflavonoids. The absolute stereostructures were elucidated by chemical, spectroscopic, and chiroptical methods. The biological properties of the new biflavonoid against several bacterial strains were evaluated.

  14. In Vitro Studies of Chromone-Tetrazoles against Pathogenic Protozoa, Bacteria, and Fungi

    Directory of Open Access Journals (Sweden)

    Pedro A. Cano

    2015-07-01

    Full Text Available In vitro studies to fourteen previously synthesized chromone-tetrazoles and four novel fluorine-containing analogs were conducted against pathogenic protozoan (Entamoeba histolytica, pathogenic bacteria (Pseudomonas aeruginosa, and Staphylococcus aureus, and human fungal pathogens (Sporothrix schenckii, Candida albicans, and Candida tropicalis, which have become in a serious health problem, mainly in tropical countries.

  15. Chrotacumines G-J, chromone alkaloids from Dysoxylum acutangulum with osteoclast differentiation inhibitory activity.

    Science.gov (United States)

    Morita, Hiroshi; Nugroho, Alfarius Eko; Nagakura, Yuta; Hirasawa, Yusuke; Yoshida, Haruka; Kaneda, Toshio; Shirota, Osamu; Ismail, Intan Safinar

    2014-06-01

    Four new chromone alkaloids, chrotacumines G-J (1-4), have been isolated from the barks of Dysoxylum acutangulum. Their structures and absolute configurations were elucidated on the basis of NMR and CD data. Chrotacumines G and J (1 and 4) showed osteoclast differentiation inhibitory activity in a dose dependent manner. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. In Vitro Studies of Chromone-Tetrazoles against Pathogenic Protozoa, Bacteria, and Fungi.

    Science.gov (United States)

    Cano, Pedro A; Islas-Jácome, Alejandro; Rangel-Serrano, Ángeles; Anaya-Velázquez, Fernando; Padilla-Vaca, Felipe; Trujillo-Esquivel, Elías; Ponce-Noyola, Patricia; Martínez-Richa, Antonio; Gámez-Montaño, Rocío

    2015-07-08

    In vitro studies to fourteen previously synthesized chromone-tetrazoles and four novel fluorine-containing analogs were conducted against pathogenic protozoan (Entamoeba histolytica), pathogenic bacteria (Pseudomonas aeruginosa, and Staphylococcus aureus), and human fungal pathogens (Sporothrix schenckii, Candida albicans, and Candida tropicalis), which have become in a serious health problem, mainly in tropical countries.

  17. Antagonism of human formyl peptide receptor 1 (FPR1) by chromones and related isoflavones.

    Science.gov (United States)

    Schepetkin, Igor A; Kirpotina, Liliya N; Khlebnikov, Andrei I; Cheng, Ni; Ye, Richard D; Quinn, Mark T

    2014-12-15

    Formyl peptide receptors (FPRs) are G protein-coupled receptors (GPCRs) expressed on a variety of cell types. Because FPRs play an important role in the regulation of inflammatory reactions implicated in disease pathogenesis, FPR antagonists may represent novel therapeutics for modulating innate immunity. Previously, 4H-chromones were reported to be potent and competitive FPR1 antagonists. In the present studies, 96 additional chromone analogs, including related synthetic and natural isoflavones were evaluated for FPR1 antagonist activity. We identified a number of novel competitive FPR1 antagonists that inhibited fMLF-induced intracellular Ca2+ mobilization in FPR1-HL60 cells and effectively competed with WKYMVm-FITC for binding to FPR1 in FPR1-HL60 and FPR1-RBL cells. Compound 10 (6-hexyl-2-methyl-3-(1-methyl-1H-benzimidazol-2-yl)-4-oxo-4H-chromen-7-yl acetate) was found to be the most potent FPR1-specific antagonist, with binding affinity Ki∼100 nM. These chromones inhibited Ca2+ flux and chemotaxis in human neutrophils with nanomolar-micromolar IC50 values. In addition, the most potent novel FPR1 antagonists inhibited fMLF-induced phosphorylation of extracellular signal-regulated kinases (ERK1/2) in FPR1-RBL cells. These antagonists were specific for FPR1 and did not inhibit WKYMVM/WKYMVm-induced intracellular Ca2+ mobilization in FPR2-HL60 cells, FPR3-HL60 cells, RBL cells transfected with murine Fpr1, or interleukin 8-induced Ca2+ flux in human neutrophils and RBL cells transfected with CXC chemokine receptor 1 (CXCR1). Moreover, pharmacophore modeling showed that the active chromones had a significantly higher degree of similarity with the pharmacophore template as compared to inactive analogs. Thus, the chromone/isoflavone scaffold represents a relevant backbone for development of novel FPR1 antagonists. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. UP780, a chromone-enriched aloe composition improves insulin sensitivity.

    Science.gov (United States)

    Yimam, Mesfin; Zhao, Jifu; Corneliusen, Brandon; Pantier, Mandee; Brownell, Lidia Alfaro; Jia, Qi

    2013-08-01

    Diabetic individuals experience elevated fasting glucose, glycosylated hemoglobin (HbA1c), and plasma insulin and impaired glucose tolerance. Adiponectin is a hormone inversely correlated with insulin resistance. Here we describe the activity of aloesin, an aloe chromone that increases adiponectin production and, when formulated with an aloe polysaccharide composition, improves the insulin sensitivity in db/db and diet-induced obese-diabetic mice. Two aloe chromones, aloesin and aloesinol, were tested in vitro for adiponectin production. Following confirmation of glucose-lowering activity in a high-fat diet (HFD)-induced mouse model, aloesin was formulated with an Aloe vera inner leaf gel powder polysaccharide preparation to yield a composition designated UP780. Efficacy of UP780 was evaluated in HDF-induced and db/db mouse models. GW1929, a synthetic peroxisome proliferator-activated receptor-γ (PPARγ) agonist, was used as a positive control. After 3 weeks of treatment of HDF-induced mice, plasma insulin levels were decreased 37.9% and 46.7% by aloesin and aloesinol, respectively. In db/db mice, the chromone- (2% chromone:98% aloe polysaccharide) enriched UP780 aloe composition showed a 33.7% and 46.0% decrease in fasting triglyceride and plasma glucose levels after 10 weeks of oral treatment, respectively. Diabetic mice gavaged with 200 mg/kg of UP780 for 10 weeks showed a 30.3% decrease in fasting blood glucose levels and a 32.2% reduction in plasma insulin. In both animal models, UP780 showed a statistically significant improvement in blood glucose clearance. These findings indicate that UP780, a chromone-standardized, aloe-based composition, could potentially be used as a natural product option to facilitate the maintenance of healthy blood glucose levels.

  19. New 2-(2-phenylethyl)chromone derivatives from the seeds of Cucumis melo L var. reticulatus.

    Science.gov (United States)

    Ibrahim, Sabrin R M

    2010-03-01

    Chemical investigation of the methanolic extract of the seeds of Cucumis melo L. var. reticulatus (Cucurbitaceae) afforded three new chromone derivatives; 5,7-dihydroxy-2-[2-(4-hydroxyphenyl)ethyl]chromone 3, 5,7-dihydroxy-2-[2-(3,4-dihydroxyphenyl)ethyl]chromone 4, and 7-glucosyloxy-5-hydroxy-2-[2-(4-hydroxyphenyl)ethyl]chromone 6, together with three known compounds; beta-amyrin 1, beta-sitosterol 2, and beta-sitosterol-3-O-beta-glucopyranoside 5. Their structures were established by UV, IR, 1D and 2D NMR, in addition to mass spectroscopic data and comparison with literature data. The n-hexane and methanolic extracts were evaluated for their antimicrobial activity, as well as cytotoxic activity using the brine shrimp bioassay.

  20. Conjugate addition of isocyanides to chromone 3-carboxylic acid: an efficient one-pot synthesis of chroman-4-one 2-carboxamides.

    Science.gov (United States)

    Neo, Ana G; Díaz, Jesús; Marcaccini, Stefano; Marcos, Carlos F

    2012-05-07

    We report a novel Lewis acid catalysed tandem reaction of isocyanides, chromone 3-carboxylic acid and nucleophiles. An experimentally very simple procedure, involving the use of microwave irradiation in the presence of a Lewis acid catalyst, affords a representative collection of chromone-2-carboxamides and chromone-2-carboxamido-3-esters in high yields, in just a few minutes. Such an unprecedented strategy is formally equivalent to a conjugate addition of isocyanides to Michael acceptors.

  1. Periodic structures induced by director reorientation in the lyotropic nematic phase of disodium cromoglycate-water

    Science.gov (United States)

    Hui, Y. W.; Kuzma, M. R.; San Miguel, M.; Labes, M. M.

    1985-07-01

    A nonequilibrium periodic structure is induced by a magnetic field H applied to an aligned lyotropic uniaxial nematic phase of disodium cromoglycate-water. A series of parallel lines perpendicular to H represents boundaries between 180° out-of-phase regions of director reorientation. The distance between the lines decreases with increasing H. The line spacing is also directly proportional to thickness of the sample (in a limited range of thickness), and a secondary periodicity, consisting of nodes in these lines, is observed in thicker samples. An extension of a theoretical model by Guyon et al. is used to qualitatively interpret the abovementioned dependencies.

  2. 3D-QSAR Investigation of Synthetic Antioxidant Chromone Derivatives by Molecular Field Analysis

    Science.gov (United States)

    Samee, Weerasak; Nunthanavanit, Patcharawee; Ungwitayatorn, Jiraporn

    2008-01-01

    A series of 7-hydroxy, 8-hydroxy and 7,8-dihydroxy synthetic chromone derivatives was evaluated for their DPPH free radical scavenging activities. A training set of 30 synthetic chromone derivatives was subject to three-dimensional quantitative structure-activity relationship (3D-QSAR) studies using molecular field analysis (MFA). The substitutional requirements for favorable antioxidant activity were investigated and a predictive model that could be used for the design of novel antioxidants was derived. Regression analysis was carried out using genetic partial least squares (G/PLS) method. A highly predictive and statistically significant model was generated. The predictive ability of the developed model was assessed using a test set of 5 compounds (r2pred = 0.924). The analyzed MFA model demonstrated a good fit, having r2 value of 0.868 and cross-validated coefficient r2cv value of 0.771. PMID:19325746

  3. Phomopsichin A–D; Four New Chromone Derivatives from Mangrove Endophytic Fungus Phomopsis sp. 33#

    Directory of Open Access Journals (Sweden)

    Meixiang Huang

    2016-11-01

    Full Text Available Four new chromone derivatives, phomopsichins A–D (1–4, along with a known compound, phomoxanthone A (5, were isolated from the fermentation products of mangrove endophytic fungus Phomopsis sp. 33#. Their structures were elucidated based on comprehensive spectroscopic analysis coupled with single-crystal X-ray diffraction or theoretical calculations of electronic circular dichroism (ECD. They feature a tricyclic framework, in which a dihydropyran ring is fused with the chromone ring. Compounds 1–5 showed weak inhibitory activities on acetylcholinesterase as well as α-glucosidase, weak radical scavenging effects on 1,1-diphenyl-2-picrylhydrazyl (DPPH as well as OH, and weak antimicrobial activities. Compounds 1–4 showed no cytotoxic activity against MDA-MB-435 breast cancer cells. Their other bioactivities are worthy of further study, considering their unique molecular structures.

  4. Identification of novel chromone based sulfonamides as highly potent and selective inhibitors of alkaline phosphatases.

    Science.gov (United States)

    al-Rashida, Mariya; Raza, Rabia; Abbas, Ghulam; Shah, Muhammad Shakil; Kostakis, George E; Lecka, Joanna; Sévigny, Jean; Muddassar, Muhammad; Papatriantafyllopoulou, Constantina; Iqbal, Jamshed

    2013-08-01

    A new series of structurally diverse chromone containing sulfonamides has been developed. Crystal structures of three representative compounds (2a, 3a and 4a) in the series are reported. All compounds were screened for their inhibitory potential against alkaline phosphatases (ALPs). Two main classes of ALP isozymes were selected for this study, the tissue non-specific alkaline phosphatase (TNALP) from bovine and porcine source and the tissue-specific intestinal alkaline phosphatases (IALPs) from bovine source. All sulfonamide compounds had a marked preference for IALP (K(i), up to 0.01 ± 0.001 μM) over TNALPs. Kinetics studies of the compounds showed competitive mode of inhibition. Molecular docking studies were carried out in order to characterize the selective inhibition of the compounds. An additional interesting aspect of these chromone sulfonamides is their inhibitory activity against ecto-5'-nucleotidase enzyme. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  5. 3D-QSAR Investigation of Synthetic Antioxidant Chromone Derivatives by Molecular Field Analysis

    Directory of Open Access Journals (Sweden)

    Jiraporn Ungwitayatorn

    2008-02-01

    Full Text Available A series of 7-hydroxy, 8-hydroxy and 7,8-dihydroxy synthetic chromone derivatives was evaluated for their DPPH free radical scavenging activities. A training set of 30 synthetic chromone derivatives was subject to three-dimensional quantitative structure-activity relationship (3D-QSAR studies using molecular field analysis (MFA. The substitutional requirements for favorable antioxidant activity were investigated and a predictive model that could be used for the design of novel antioxidants was derived. Regression analysis was carried out using genetic partial least squares (G/PLS method. A highly predictive and statistically significant model was generated. The predictive ability of the developed model was assessed using a test set of 5 compounds (r2pred = 0.924. The analyzed MFA model demonstrated a good fit, having r2 value of 0.868 and crossvalidated coefficient r2cv value of 0.771.

  6. Phomopsichin A-D; Four New Chromone Derivatives from Mangrove Endophytic Fungus Phomopsis sp. 33.

    Science.gov (United States)

    Huang, Meixiang; Li, Jing; Liu, Lan; Yin, Sheng; Wang, Jun; Lin, Yongcheng

    2016-11-22

    Four new chromone derivatives, phomopsichins A-D (1-4), along with a known compound, phomoxanthone A (5), were isolated from the fermentation products of mangrove endophytic fungus Phomopsis sp. 33#. Their structures were elucidated based on comprehensive spectroscopic analysis coupled with single-crystal X-ray diffraction or theoretical calculations of electronic circular dichroism (ECD). They feature a tricyclic framework, in which a dihydropyran ring is fused with the chromone ring. Compounds 1-5 showed weak inhibitory activities on acetylcholinesterase as well as α-glucosidase, weak radical scavenging effects on 1,1-diphenyl-2-picrylhydrazyl (DPPH) as well as OH, and weak antimicrobial activities. Compounds 1-4 showed no cytotoxic activity against MDA-MB-435 breast cancer cells. Their other bioactivities are worthy of further study, considering their unique molecular structures.

  7. Flavanones and Chromones from Salicornia herbacea Mitigate Septic Lethality via Restoration of Vascular Barrier Integrity.

    Science.gov (United States)

    Tuan, Nguyen Quoc; Lee, Wonhwa; Oh, Joonseok; Kulkarni, Roshan Rajan; Gény, Charlotte; Jung, Byeongjin; Kang, Hyejin; Bae, Jong-Sup; Na, MinKyun

    2015-11-25

    Salicornia herbacea is an annual halophytic glasswort that has been employed as a culinary vegetable, salad, and traditional medicinal resource. Chemical investigation of the aerial parts of S. herbacea led to the isolation of two new (1, 2) and known (3) flavanones as well as a new nature-derived (4) and two known chromone derivatives (5, 6). These purified compounds were evaluated for their suppressive potentials against the release of high-mobility group box 1 protein (HMGB1), which has captured attention as a viable target for alleviating serious septic manifestations or septicemia. The phenolic compounds improved the survival rates of cecal ligation and puncture operation (CLP) in murine models, simulating severe septic shock and its related complications, to 40-60%. These results collectively validate that flavanone- and chromone-based secondary metabolites may serve as prospective prodrugs or food additives that may be commercialized for the control of septic complications and lethality.

  8. Novel Chromone Derivatives from Marine Fungus Aspergillus versicolor Isolated from the Sponge Xestospongia exigua

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    From the marine sponge Xestospongia exigua, fungal isolates of Aspergillus versicolor (Vuill)Triab were obtained. Isolation and purification of ethyl acetate extracts from culture filtrates of the fungus led to yield six new chromone derivatives namely aspergione A, aspergione B, aspergione C, aspergione D, aspergione E, aspergione F. The structures of all the new compounds were established on the basis of extensive spectroscopy (UV, MS, 1H and 13C NMR, COSY, HMQC and HMBC) analysis.

  9. Structural characterization of some N-phenyl-4-oxo-4H-2-chromone carboxamides.

    Science.gov (United States)

    Gomes, Ligia Rebelo; Low, John Nicolson; Cagide, Fernando; Gaspar, Alexandra; Reis, Joana; Borges, Fernanda

    2013-06-01

    N-phenyl-4-oxo-4H-2-chromone carboxamides were found to be inactive as MAO inhibitors in contrast with their N-phenyl-4-oxo-4H-3-chromone carboxamide isomers. In order to obtain a close insight into the docking mechanism for this family of compounds, the molecular and supramolecular structures of nine N-phenyl-4-oxo-4H-2-chromone carboxamides were determined. It was found that, in most of the secondary structures, the N(amido) and the O(carboxyl) of the carboxamide residue participate in strong intramolecular interactions, with the O atom of the chromene ring and with the H(ortho)-C (phenyl), respectively. When the phenyl ring had accessible acceptors as substituents a third intramolecular hydrogen bond was also observed. As a consequence, rotations of the chromone and phenyl rings around the N-C(alpha) and C(alpha')-C=O are constrained and the compounds were found to be more planar than would otherwise be expected. The deviation from planarity of the whole molecule can be quantified by the dihedral angles between mean planes of the aromatic rings and it was found that they were mainly affected by the degree of torsion of the phenyl ring with respect to the amide residue. The molecular conformations assumed by the secondary amides clearly contrast with that of a related tertiary amide that was also determined in this study. The unavailability of the N in this compound as a donor strongly influences the molecular isomerism and conformation. This analysis demonstrates that the molecules can be classified into four groups depending on the types of interactions formed as described above. If the secondary N(amido) of the carboximide is involved in two intramolecular interactions then this atom does not form any intermolecular contacts. In all other cases it does and the supramolecular structure formed is in most cases supplemented by weak C-H···O interactions.

  10. Determination of a new chromone from Aurantii Fructus Immaturus by DFT/GIAO method.

    Science.gov (United States)

    Jiang, Zhe; Liu, Fang; Zhong, Aijiao; Dugu, Jiaxiu; Li, Xuezheng

    2016-01-01

    Investigation of EtOAc fraction from the 95% ethanol extract of Aurantii Fructus Immaturus led to the isolation of one new chromone (1) and seven known flavonoids (2-8). Their structures were elucidated mainly by NMR and HR-ESI-MS, as well as on comparison with the reported NMR data. The final substituent pattern of 1 was defined by comparison of (13)C NMR data calculated by DFT/GIAO with those of experimental NMR data.

  11. Polysaccharide enhances Radix Saposhnikoviae efficacy through inhibiting chromones decomposition in intestinal tract

    Science.gov (United States)

    Yang, Jing-Ming; Jiang, Hua; Dai, Hong-Liang; Wang, Zi-Wei; Jia, Gui-Zhi; Meng, Xiang-Cai

    2016-01-01

    Vegetative but not reproductive stage of Saposhnikovia divaricate (Turxz.) schischk possesses pharmacological activities. However, our recent study showed that reproductive S. divaricate supplemented with polysaccharide showed evidently elevated pharmacological activities and increased cimifugin content in rat serum. The aims of present study were to assess the influence of polysaccharides on the chromones pharmacological activities in Radix Saposhnikoviae (RS), the dried root of vegetative stage of S. divaricate, and to explore the underlying mechanisms. Only cimifugin was detected in the plasma of chromone treated animals and RS polysaccharide significantly increased the plasma content of cimifugin. It was shown that neither cimifugin absorption nor glycoside components transformation in simulated digestive fluid was affected by RS polysaccharide. However, a significant promotion of transformation of cimifugin to more stable prime-O-glucosylcimifugin (PGCN) by RS polysaccharide, and a protective effect of polysaccharide on chromone components were observed in small intestine solutions. Meanwhile, RS polysaccharide produced a significant elevation of cimifugin and PGCN concentration in vivo. Based on these findings, we concluded that RS polysaccharide could greatly increase the content of cimifugin, which might be related to its degradation-proof effect on cimifugin, via transforming cimifugin to comparatively more stable PGCN and spatial structure protection. PMID:27595868

  12. Chromone derivatives from Halenia elliptica and their anti-HBV activities.

    Science.gov (United States)

    Sun, Yu-wei; Liu, Guang-ming; Huang, Hai; Yu, Pei-zhong

    2012-03-01

    Nine water-soluble chromone derivatives, including chromone-2-carboxylic acids, 2-methylchromones and their structural hybrids, were isolated from aerial tissues of Halenia elliptica (Gentianaceae), six of which were previously unknown. Their structures were elucidated by comprehensive mass, 1D and 2D NMR spectroscopic analyses and chemical derivatization. Two unstable structural hybrids of chromone-2-carboxylic acids and 2-methylchromones, viz. 3-acetyl-8-hydroxy-4H-1-benzopyran-4-one-2-carboxylic acid (halenic acid C) and 2-(8-hydroxy-2-methyl-4H-1-benzopyran-4-one-3-yl)-2-oxoacetic acid (halenichromone A), were isomers and were interconvertible. The proposed mechanism of their acid-catalyzed isomerization in aqueous solvent is described. In addition, 2-methylchromones, 8-hydroxy-2-methyl-4H-1-benzopyran-4-one, and 8-methoxy-2-methyl-4H-1-benzopyran-4-one, were found to exhibit a strong inhibitory effect towards hepatitis B virus (HBV) in vitro without showing significant cytotoxicity. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Novel chromone and xanthone derivatives: Synthesis and ROS/RNS scavenging activities.

    Science.gov (United States)

    Proença, Carina; Albuquerque, Hélio M T; Ribeiro, Daniela; Freitas, Marisa; Santos, Clementina M M; Silva, Artur M S; Fernandes, Eduarda

    2016-06-10

    Chromones and xanthones are oxygen-containing heterocyclic compounds acknowledged by their antioxidant properties. In an effort to develop novel agents with improved activity, a series of compounds belonging to these chemical classes were prepared. Their syntheses involve the condensation of appropriate 2-methyl-4H-chromen-4-ones, obtained via Baker-Venkataraman rearrangement, with (E)-3-(3,4-dimethoxyphenyl)acrylaldehyde to provide the corresponding 2-[(1E,3E)-4-(3,4-dimethoxyphenyl)buta-1,3-dien-1-yl]-4H-chromen-4-ones. Subsequent electrocyclization and oxidation of these compounds led to the synthesis of 1-aryl-9H-xanthen-9-ones. After cleavage of the protecting groups, hydroxylated chromones and xanthones were assessed as scavenging agents against both reactive oxygen species (ROS) [superoxide radical (O2(•-)), hydrogen peroxide (H2O2), hypochlorous acid (HOCl), singlet oxygen ((1)O2), and peroxyl radical (ROO(•))] and reactive nitrogen species (RNS) [nitric oxide ((•)NO) and peroxynitrite anion (ONOO(-))]. Generally, all the tested new hydroxylated chromones and xanthones exhibited scavenger effects dependent on the concentration, with IC50 values found in the micromolar range. Some of them were shown to have improved scavenging activity when compared with previously reported analogues, allowing the inference of preliminary conclusions on the structure-activity relationship. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  14. Deriving binary phase diagrams for chromonic materials in water mixtures via fluorescence spectroscopy: cromolyn and water.

    Science.gov (United States)

    Van Hecke, Gerald R; Karukstis, Kerry K; Rayermann, Scott

    2015-01-14

    We report here the first example of a new and novel method of determining the binary temperature-composition phase diagram of a chromonic material in water using its intrinsic fluorescence. Disodium cromoglycate, or cromolyn, is an anti-allergy medicine representative of a class of compounds known as the chromonics. We have discovered that cromolyn's fluorescence is very sensitive to the polarity, hence structure, of the phase it exhibits. The fluorescence signal shifts its wavelength maximum and its shape depending on whether the cromolyn is a single phase or in coexisting phases. Since the signal due to individual phases can be identified, the fluorescence signal can reveal the temperature-induced transitions between single phase and phase coexistence regions. By studying such fluorescence data for different compositions, an isobaric temperature-composition phase diagram may be constructed. We present here a phase diagram derived from fluorescence studies that is in agreement with previous determinations using other techniques. Our results suggest that the binary phase diagrams of other intrinsically fluorescent chromonic materials, such as perylene monoimide and bisimide derivatives used in organic optoelectronic devices, solar cells, and light-emitting diodes, can be studied in water using an analogous fluorescence approach.

  15. Radioprotective effects of 2-imino-3[(chromone-2-yl)carbonyl]thiazolidines against {gamma}-irradiation in mice

    Energy Technology Data Exchange (ETDEWEB)

    Hosseinimehr, S.J.; Shafiee, A. [Tehran Univ. of Medical Sciences (Iran, Islamic Republic of). Faculty of Pharmacy; Mozdarani, H. [Tarbiat Modarres Univ., Tehran (Iran, Islamic Republic of). Faculty of Medical Sciences; Akhlagpour, S. [Tehran Univ. of Medical Sciences (Iran, Islamic Republic of). Faculty of Medicine; Froughizadeh, M. [Novin Medical Radiation Inst., Tehran (Iran, Islamic Republic of)

    2002-09-01

    A series of 2-imino-3-[(chromone-2-yl)carbonyl]thiazolidines substituted at the C-5 and/ or C-7 positions of a chromone ring were synthesized. The in vivo toxicity and radioprotective efficacy of these agents were evaluated in male NMRI mice against cobalt-60 {gamma}-rays. The lethal dose 50% (LD{sub 50}) values as determined by a Probit analysis, were 659, 1216 and 790 mg/kg for compounds, 2, 3 and 4, respectively. For studying radioprotective effects, one half of the toxic LD{sub 50} values were used, namely 330, 605 and 395 mg/kg for compounds 2, 3 and 4, respectively. The dose reduced factor (DRF) was determined by dividing the LD{sub 50/30} values obtained from the radiation survival curve in the presence of a radioprotective agent by the LD{sub 50/30} value obtained from a control radiation survival curve. A compound with a hydroxyl group substituent at the C-5 position afforded better radioprotective activity than those without this substituent. The radioprotective effect of chromone having a hydroxyl group at only the C-7 position was similar to that of the unsubstituted chromone. The most active compound has hydroxyl groups at the C-5 and C-7 positions of the chromone ring; it had a DRF of 1.48. (author)

  16. Biaxial nematic liquid crystals theory, simulation and experiment

    CERN Document Server

    Luckhurst, Geoffrey R

    2015-01-01

    Liquid Crystals are a state of matter that have properties between those of conventional liquid and those of a solid crystal. Thermotropic liquid crystals react to changes in temperature or, in some cases, pressure. The reaction of lyotropic liquid crystals, which are used in the manufacture of soaps and detergents, depends on the type of solvent they are mixed with. Since the accidental discovery of the chiral nematic (ordered) phase in 1888 many liquid crystal phases have been found, sometimes by chance and sometimes by design. The existence of one such phase was predicted by Freiser in 197

  17. Synthesis of Succinimide-Containing Chromones, Naphthoquinones, and Xanthones under Rh(III) Catalysis: Evaluation of Anticancer Activity.

    Science.gov (United States)

    Han, Sang Hoon; Kim, Saegun; De, Umasankar; Mishra, Neeraj Kumar; Park, Jihye; Sharma, Satyasheel; Kwak, Jong Hwan; Han, Sangil; Kim, Hyung Sik; Kim, In Su

    2016-12-16

    The weakly coordinating ketone group directed C-H functionalizations of chromones, 1,4-naphthoquinones, and xanthones with various maleimides under rhodium(III) catalysis are described. These protocols efficiently provide a range of succinimide-containing chromones, naphthoquinones, and xanthones with excellent site selectivity and functional group compatibility. All synthetic compounds were screened for in vitro anticancer activity against human breast adenocarcinoma cell lines (MCF-7). In particular, compounds 7aa and 7ca with a naphthoquinone scaffold were found to be highly cytotoxic, with an activity competitive with anticancer agent doxorubicin.

  18. Chrotacumines E and F, two new chromone-alkaloid analogs from Dysoxylum acutangulum (Meliaceae) leaves.

    Science.gov (United States)

    Izwan Mohd Lazim, Mohd; Safinar Ismail, Intan; Shaari, Khozirah; Abd Latip, Jalifah; Ali Al-Mekhlafi, Nabil; Morita, Hiroshi

    2013-09-01

    A chemical investigation of the alkaloidal fraction of Dysoxylum acutangulum leaves led to the isolation and characterization of two new chromone alkaloid analogs named chrotacumines E and F (1 and 2, resp.). Structure elucidation of 1 and 2 was achieved by spectroscopic analyses, including 2D-NMR. Both of these alkaloids exhibited modest activities as tyrosinase inhibitors with 29.2 and 25.8% inhibition at 100 μg/ml, respectively. Copyright © 2013 Verlag Helvetica Chimica Acta AG, Zürich.

  19. Chroman-4-one and chromone based somatostatin β-turn mimetics.

    Science.gov (United States)

    Fridén-Saxin, Maria; Seifert, Tina; Malo, Marcus; da Silva Andersson, Krystle; Pemberton, Nils; Dyrager, Christine; Friberg, Annika; Dahlén, Kristian; Wallén, Erik A A; Grøtli, Morten; Luthman, Kristina

    2016-05-23

    A scaffold approach has been used to develop somatostatin β-turn mimetics based on chroman-4-one and chromone ring systems. Such derivatives could adopt conformations resembling type II or type II' β-turns. Side chain equivalents of the crucial Trp8 and Lys9 in somatostatin were introduced in the 2- and 8-positions of the scaffolds using efficient reactions. Interestingly, this proof-of-concept study shows that 4 and 9 have Ki-values in the low μM range when evaluated for their affinity for the sst2 and sst4 receptors. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  20. Liquid crystalline thermosetting polyimides. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hoyt, A.E.; Huang, S.J. [Connecticut Univ., Storrs, CT (United States). Inst. of Materials Science

    1993-07-01

    Phase separation of rodlike reinforcing polymers and flexible coil matrix polymers is a common problem in formulating molecular composites. One way to reduce phase separation might be to employ liquid crystalline thermosets as the matrix material. In this work, functionally terminated polyimide oligomers which exhibit lyotropic liquid crystalline behavior were successfully prepared. Materials based on 2,2{prime}-bis(trifluoromethyl)-4,4{prime}-diaminobiphenyl and 3,3{prime},4,4{prime}-biphenylenetetra-carboxylic dianhydride have been synthesized and characterized.

  1. The Effect of Liquid Crystalline Structures on Antiseizure Properties of Aqueous Solutions of Ethoxylated Alcohols

    OpenAIRE

    2010-01-01

    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 ex...

  2. Thermodynamic study of two molecules which occur in coal's pyrolysis products: chromone and xanthone

    Energy Technology Data Exchange (ETDEWEB)

    Sabbah, R.; El Watik, L.

    The enthalpy of combustion and sublimation of chromone and xanthone, their enthalpy of fusion and the temperature of their triple point have been determined. From the experimental results it was possible to calculate the resonance energy and the enthalpy of atomisation, also to find and discuss the correlation between energy values and the structure of these molecules. 19 refs., 1 fig., 6 tabs.

  3. Lewis base catalyzed [4+2] annulation of electron-deficient chromone-derived heterodienes and acetylenes.

    Science.gov (United States)

    Dückert, Heiko; Khedkar, Vivek; Waldmann, Herbert; Kumar, Kamal

    2011-04-26

    Lewis base catalyzed [4+2] annulation reactions between electron-deficient chromone oxa- and azadienes and acetylene carboxylates provide tricyclic benzopyrones inspired by natural products. An asymmetric synthesis of the tricyclic benzopyrones was developed by using modified cinchona alkaloids as enantiodifferentiating Lewis base catalysts.

  4. Self-Assembled Soft Optical Negative Index Materials

    Science.gov (United States)

    2008-08-05

    Nanorods by Lyotropic Chromonic Materials’, Langmuir, 24 (2008), 13833-37. [15]. A. B. Golovin , and O. D. Lavrentovich, ’Electrically...Reconfigurable Optical Metamaterial Based on Colloidal Dispersion of Metal Nanorods in Dielectric Fluid’, Applied Physics Letters, 95 (2009) [16]. A. B. Golovin ...of Metal Nano-Rods in Dielectric Fluids’, Liquid Crystals Xiv, 7775 (2010) [17]. A. B. Golovin , J. Xiang, H. S. Park, L. Tortora, Y. A. Nastishin

  5. Synthesis, biological evaluation and molecular docking studies of chromone hydrazone derivatives as α-glucosidase inhibitors.

    Science.gov (United States)

    Wang, Guangcheng; Chen, Ming; Wang, Jing; Peng, Yaping; Li, Luyao; Xie, ZhenZhen; Deng, Bing; Chen, Shan; Li, Wenbiao

    2017-07-01

    A series of chromone hydrazone derivatives 4a-4p have been synthesized, characterized by (1)H NMR and (13)C NMR and evaluated for theirinvitro α-glucosidase inhibitory activity. Out of these tested compounds, six (4a, 4b, 4d, 4j, 4o and 4p) displayed potent α-glucosidase inhibitory activity with IC50 values in the range of 20.1±0.19μM to 45.7±0.23μM, as compared to the standard drug acarbose (IC50=817.38±6.27μM). Among this series, compound 4d (IC50=20.1±0.19μM) with 4-sulfonamide substitution at phenyl part of hydrazide was found to be the most active compound. Lineweaver-Burk plot analysis indicated that compound 4d is a non-competitive inhibitor of α-glucosidase. The binding interactions of the most active analogs were confirmed through molecular docking studies. Docking studies showed 4d are interacting with the residues Glu-276, Asp-214, Asp-349 and Arg-439 through hydrogen bonds, arene-anion and arene-cation interactions. In summary, our studies shown that these chromone hydrazone derivatives are a new class of α-glucosidase inhibitors. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Carboxymethyl flavonoids and a chromone with antimicrobial activity from Selaginella moellendorffii Hieron.

    Science.gov (United States)

    Zou, ZhenXing; Xu, PingSheng; Wu, CanRong; Zhu, WeiXing; Zhu, GangZhi; He, XiaoAi; Zhang, GuoGang; Hu, JianZhong; Liu, Shao; Zeng, Wei; Xu, KangPing; Tan, GuiShan

    2016-06-01

    Five new carboxymethyl flavonoids named 5-carboxymethyl-3', 4', 7-trihydroxyflavone (1), (2S)- 5-carboxymethyl-3', 4', 7-trihydroxyflavonone (2a), (2R)-5-carboxymethyl-3', 4', 7-trihydroxyflavonone (2b), (2S)-5-carboxymethyl-4', 7-dihydroxyflavonone (3), 5- carbomethoxymethyl-4', 7-dihydroxyflavone (4), and a new chromone named 5-carboxymethyl-7-hydroxychromone (5), together with two known compounds 5-carboxymethyl-4'-hydroxyflavone-7-O-β-d-glucopyranoside (6), 5-carboxymethyl-4', 7-dihydroxyflavone (7) were isolated from Selaginella moellendorffii Hieron. Their structures including absolute configuration were elucidated by extensive spectroscopic methods and experimental electronic circular dichroism (ECD) spectra. What's worth mentioning is that a carboxymethyl substituent appeared at the C-5 position of all isolated compounds, only recently discovered in genus Selaginella. Compounds 2a and 2b were identified as a pair of chiral isomers; compound 5 was discovered as the first chromone comprising a carboxymethyl side chain. Furthermore, all compounds were evaluated for their antibacterial activities against various Gram-positives and Gram-negatives, and compared to the reference drugs amoxicillin and norfloxacin. As a result, compounds 3 and 4 exhibited as potent antimicrobial agents with a broad spectrum, and compound 5 appeared as the most promising one to combat Gram-positives. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Cytotoxic dihydrothiophene-condensed chromones from the marine-derived fungus Penicillium oxalicum.

    Science.gov (United States)

    Sun, Yu-Lin; Bao, Jie; Liu, Kai-Sheng; Zhang, Xiao-Yong; He, Fei; Wang, Yi-Fei; Nong, Xu-Hua; Qi, Shu-Hua

    2013-10-01

    Two new dihydrothiophene-condensed chromones and a new natural chromone, namely oxalicumones A-C (1-3), respectively, were isolated from a culture broth of a marine-derived fungus, Penicillium oxalicum. The structures of 1-3 and acetylated derivatives of 1 (4-7) were elucidated on the basis of spectroscopic methods and chemical reactions. The absolute configuration of 1 and 2 were established by using the modified Mosher ester method and circular dichroism data of an in situ formed [Rh2(OCOCF3)4] and [Mo2(OAc)4] complex. (R)-MTPA ester of 1 showed cytotoxicity against A375, SW-620, and HeLa carcinoma cell lines with IC50 values of 8.9, 7.8, and 18.4 µM, respectively. Compound 1 displayed cytotoxicity against A375 and SW-620 cell lines with IC50 values of 11.7 and 22.6 µM, respectively. The structure-biological activity relationship of 1 was discussed. Georg Thieme Verlag KG Stuttgart · New York.

  8. Two polymorphs of N-(2-methoxyphenyl)-4-oxo-4H-chromone-3-carboxamide.

    Science.gov (United States)

    Gomes, Ligia R; Low, John Nicolson; Borges, Fernanda; Cagide, Fernando

    2013-08-01

    The title compound, C₁₇H₁₃NO₄, crystallizes in two polymorphic forms, each with two molecules in the asymmetric unit and in the monoclinic space group P2₁/c. All of the molecules have intramolecular hydrogen bonds involving the amide group. The amide N atoms act as donors to the carbonyl group of the pyrone and also to the methoxy group of the benzene ring. The carbonyl O atom of the amide group acts as an acceptor of the β and β' C atoms belonging to the aromatic rings. These intramolecular hydrogen bonds have a profound effect on the molecular conformation. In one polymorph, the molecules in the asymmetric unit are linked to form dimers by weak C-H∙∙∙O interactions. In the other, the molecules in the asymmetric unit are linked by a single weak C-H∙∙∙O hydrogen bond. Two of these units are linked to form centrosymmetric tetramers by a second weak C-H∙∙∙O interaction. Further interactions of this type link the molecules into chains, so forming a three-dimensional network. These interactions in both polymorphs are supplemented by π-π interactions between the chromone rings and between the chromone and methoxyphenyl rings.

  9. 3D-QSAR studies on chromone derivatives as HIV-1 protease inhibitors

    Science.gov (United States)

    Ungwitayatorn, Jiraporn; Samee, Weerasak; Pimthon, Jutarat

    2004-02-01

    The three-dimensional quantitative structure-activity relationship (3D-QSAR) approach using comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) was applied to a series of 30 chromone derivatives, a new class of HIV-1 protease inhibitors. The best predictive CoMFA model gives cross-validated r2 ( q2)=0.763, non-cross-validated r2=0.967, standard error of estimate ( S)=5.092, F=90.701. The best CoMSIA model has q2=0.707, non-cross-validated r2=0.943, S=7.018, F=51.734, included steric, electrostatic, hydrophobic, and hydrogen bond donor fields. The predictive ability of these models was validated by a set of five compounds that were not included in the training set. The calculated (predicted) and experimental inhibitory activities were well correlated. The contour maps obtained from CoMFA and CoMSIA models were in agreement with the previous docking study for this chromone series.

  10. Towards the development of chromone-based MEK1/2 modulators.

    Science.gov (United States)

    Redwan, Itedale Namro; Dyrager, Christine; Solano, Carlos; Fernández de Trocóniz, Guillermo; Voisin, Laure; Bliman, David; Meloche, Sylvain; Grøtli, Morten

    2014-10-06

    Inhibition or allosteric modulation of mitogen-activated protein kinase kinases MEK1 and MEK2 (MEK1/2) represent a promising strategy for the discovery of new specific anticancer agents. In this paper, structure-based design, beginning from the lead compound PD98059, was used to study potential structural modifications on the chromone structure in order to obtain highly potent derivatives that target the allosteric pocket in MEK1. Subsequently, a small series of PD98059 analogs were synthesized to provide a first generation of chromone-based derivatives that inhibit the activation of MEK1 with IC50 values as low as 30 nM in vitro. Complementary cellular studies also showed that two of the compounds in the series inhibit the activity of MEK1/2 with IC50 values in the nanomolar range (73-97 nM). In addition, compounds in this series were found to inhibit the proliferation of a small panel of human cancer cell lines. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  11. Comparative study of stimulated proton-transfer luminescence of three chromones

    Energy Technology Data Exchange (ETDEWEB)

    Parthenopoulos, D.A.; Kasha, M. (Florida State Univ., Tallahassee (United States)); McMorrow, D. (Naval Research Lab., Washington, DC (United States))

    1991-04-04

    The contrasting behavior of three related chromones with respect to amplified spontaneous emission (ASE) and laser action as intramolecular proton-transfer laser systems at room temperature is investigated. The intramolecular proton-transfer laser is considered a chemical laser in which the excited tautomer species is produced by a chemical reaction after photon-pumping activating a four-level laser system. The three chromones studied are 2-methyl-3-hydroxychromone, 2-phenyl-3-hydroxychromone (3-hydroxyflavone), and the natural product fisetin (3,3{prime},4{prime},7-tetrahydroxyflavone), each of which exhibits good proton-transfer fluorescences in the 500-nm region, with respective quantum yields of 0.29 (MCH), 0.36 (MCH), and 0.16 (dioxane). Low-temperature spectroscopic study and picosecond transient absorption spectroscopy reveals that fluorescence quenching from molecular aggregation and transient parasitic S{sub n}{prime} {l arrow} S{sub 1}{prime} absorption of the tautomer both contribute to nonobservability of ASE and lasing action in the 2-methyl-3-hydroxychromone, in contrast to excellent ASE/lasing characteristics of the 3-hydroxyflavone and fisetin under comparable conditions.

  12. Relationship between Expression of Chalcone Synthase Genes and Chromones in Artificial Agarwood induced by Formic Acid Stimulation Combined with Fusarium sp. A2 Inoculation.

    Science.gov (United States)

    Chen, Xiaodong; Zhu, Xiaoling; Feng, Meirou; Zhong, Zhaojian; Zhou, Xin; Chen, Xiaoying; Ye, Wei; Zhang, Weimin; Gao, Xiaoxia

    2017-04-25

    Agarwood (gaharu) is a fragrant resin produced in the heartwood of resinous Gyrinops and Aquilaria species. Artificial agarwood samples were obtained from Aquilaria sinensis (Lour.) Gilg using formic acid (FA) stimulation combined with Fusarium sp. A2 inoculation. The relationship between the expression of chalcone synthase genes (CHS) and dynamic changes in chromone content was explored in resin-deposited parts of the trunks of A. sinensis. CHS gene expression levels were detected by qRT-PCR analysis. The chemical composition of agarwood obtained from the heartwood of A. sinensis before and within 1 year after induction was determined by GC-MS. After induction with FA stimulation combined with F. sp. A2 inoculation, the CHS1 gene showed relatively high expression, whereas the CHS2 gene showed low expression. The relative gene expression level of CHS1 peaked at 12 months, with a 153.1-fold increase, and the dominant period of the CHS2 gene expression was 10 months with a 14.13-fold increase. Moreover, chromones were not detected until after 2 months, and a large proportion of chromone compounds were detected after 4 months. Chromone content increased with time and peaked at 12 months. CHS1 gene expression was significantly correlated with 6-hydroxy-2-(2-phenylethyl)chromone accumulation, and CHS2 gene expression was significantly correlated with 5-hydroxy-6-methoxy-2-(2-phenylethyl)chromone accumulation. CHS gene expression was extremely sensitive to FA stimulation combined with F. sp. A2 inoculation and responded to late-onset injury. CHS genes expression also preceded the chromone accumulation. This work laid the foundation for studies on the mechanism by which genes regulate chromone biosynthesis pathways during the formation of agarwood resin in A. sinensis.

  13. Characterization and Analysis of 2-(2-Phenylethyl)-chromone Derivatives from Agarwood (Aquilaria crassna) by Artificial Holing for Different Times.

    Science.gov (United States)

    Yang, Jinling; Dong, Wenhua; Kong, Fandong; Liao, Ge; Wang, Jun; Li, Wei; Mei, Wenli; Dai, Haofu

    2016-07-13

    A total of fifty-six chromones, including seven 5,6,7,8-tetrahydro-2-(2-phenylethyl)-chromones (THPECs), five 5,6-epoxy-2-(2-phenylethyl)chromones (EPECs), seven 5,6:7,8-diepoxy-2-(2-phenylethyl)chromones (DEPECs) and thirty-seven 2-(2-phenylethyl)chromones of the flidersia type (FTPECs), were characterized by HPLC/DAD/ESI/MS/MS in three agarwood samples (from Aquilaria crassna) induced by artificial holing with different holing times. The characteristic fragmentation behavior of DEPECs and EPECs, and the methods to distinguish these four types of chromones by MS analysis were described for the first time. In addition, it was found that the relative contents of DEPECs and EPECs were down-regulated, while the relative contents of THPECs and FTPECs were up-regulated for the samples from two, four and five years of the agarwood formation time. However, the relative contents of six most widespread and abundant FTPECs presented roughly upward based on the formation time. These results could be referenced to distinguish different agarwood samples collected from different formation time.

  14. Unusual effects of SCN and lyotropic anions on contractility of vascular smooth muscle from female rats.

    Science.gov (United States)

    Zhang, A M; Altura, B T; Altura, B M

    1991-08-01

    Replacement of extracellular chloride ions by thiocyanate anions (SCN-) followed by washout in normal chloride-containing solution produced contractions in isolated rat aortas and portal veins of female rats followed by slow relaxation; these contractions consisted of fast and slow phases. These SCN(-)-induced biphasic contractions were also noted in rat aortas precontracted by 80 mM KCl and 100 microM noradrenaline. No differences were noted between isolated aortic precontracted by 80 mM KCl and 100 microM noradrenaline. No differences were noted between isolated aortic strips versus intact ring preparations. The SCN(-)-induced contractions in both the aorta and portal vein were inhibited markedly by denervation with 6-hydroxydopamine. Use of prazosin, rauwolscine, propranolol, atropine, methysergide, diphenydramine, indomethacin or procaine (10(-3) M) failed to alter the SCN(-)-induced responses. However, use of phentolamine at 10(-5) M, but not at lower concentrations of the drug, resulted in complete inhibition of SCN(-)-induced contractions. Treatment of the vascular tissues with EGTA (5 mM) or incubation in Ca(2+)-free media abolished the SCN(-)-induced contractile responses. Treatment with verapamil (10(-6) M) or washing in Ca(2+)-free Krebs Ringer solution after incubation with SCN(-)-Krebs Ringer selectively inhibited the slow phases of the aortic contractions. Replacement of SCN- anions with other foreign monovalent anions or with sucrose modified the amplitude of the SCN(-)-induced contractions. These foreign anions seemed to follow a relative order of potency similar to that for a lyotropic series of anions, where acetate greater than isethionate greater than chloride greater than bromide greater than nitrate greater than iodide ions.(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Highly oxygenated chromones from mangrove-derived endophytic fungus Rhytidhysteron rufulum.

    Science.gov (United States)

    Chokpaiboon, Supichar; Choodej, Siwattra; Boonyuen, Nattawut; Teerawatananond, Thapong; Pudhom, Khanitha

    2016-02-01

    Five highly oxygenated chromones, rhytidchromones A-E, were isolated from the culture broth of a mangrove-derived endophytic fungus, Rhytidhysteron rufulum, isolated from Thai Bruguiera gymnorrhiza. Their structures were determined by analysis of 1D and 2D NMR spectroscopic data. The structure of rhytidchromone A was further confirmed by single-crystal X-ray diffraction analysis. These compounds were evaluated for cytotoxicity against four cancer cell lines (MCF-7, Hep-G2, Kato-3 and CaSki). All compounds, except for rhytidchromone D, displayed cytotoxicity against Kato-3 cell lines with IC50 values ranging from 16.0 to 23.3μM, while rhytidchromones A and C were active against MCF-7 cells with IC50 values of 19.3 and 17.7μM, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Exploiting the Chromone Scaffold for the Development of Inhibitors of Corticosteroid Biosynthesis.

    Science.gov (United States)

    Gobbi, Silvia; Hu, Qingzhong; Zimmer, Christina; Engel, Matthias; Belluti, Federica; Rampa, Angela; Hartmann, Rolf W; Bisi, Alessandra

    2016-03-24

    The inhibition of corticosteroid biosynthesis could be considered as an emerging strategy to reduce their abnormally high levels, and in this framework CYP11B1 and CYP11B2 represent the most promising targets. In continuing our studies on flavonoid-like scaffolds as privileged structures in medicinal chemistry, in this paper we describe a small library of pyridyl- and imidazolylmethylchromones as potential inhibitors of these enzymes. Testing results proved that position 3 of the chromone scaffold is the most favorable for the introduction of the heme-coordinating heterocycles and, among them, the 4-imidazolyl moiety is the most convenient for the interaction with the heme iron of the selected cytochromes. A low nanomolar inhibitor of CYP11B1 (5c) was obtained, endowed with reasonable selectivity toward CYP11B2 and able to better discriminate with respect to CYP17 and CYP19.

  17. Synthesis, carbonic anhydrase inhibition and cytotoxic activity of novel chromone-based sulfonamide derivatives.

    Science.gov (United States)

    Awadallah, Fadi M; El-Waei, Tamer A; Hanna, Mona M; Abbas, Safinaz E; Ceruso, Mariangela; Oz, Beyza Ecem; Guler, Ozen Ozensoy; Supuran, Claudiu T

    2015-01-01

    Four series of sulfonamides incorporating chromone moieties were synthesized and assessed for their cytotoxic activity against MCF-7 and A-549 cell lines, considering the fact that some of these tumors overexpress isoforms of carbonic anhydrase (CA, EC 4.2.1.1) which is inhibited by sulfonamides. Most new sulfonamides showed weak inhibitory activity against the offtarget, cytosolic isoforms hCA I, II but effectively inhibited the tumor-associated hCA IX and XII. The most active compounds featured a primary SO2NH2 group and were active in the low micromolar range against MCF-7 and A-549 cell lines. Compound 4a showed IC50 of 0.72 and 0.50 μM against MCF-7 and A-549 cell lines, respectively, and was further evaluated for its proapoptotic activity which proved enhanced in both tumor types. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  18. Sesquiterpene coumarin and sesquiterpene chromone derivatives from Ferula ferulaeoides (Steud.) Korov.

    Science.gov (United States)

    Meng, He; Li, Guoyu; Huang, Jian; Zhang, Ke; Wang, Hangyu; Wang, Jinhui

    2013-04-01

    Five novel compounds - three sesquiterpene coumarin derivatives, ferulin A (1), B (2), and C (3), and two sesquiterpene chromone derivatives, ferulin D (4) and E (5), together with eleven known compounds (6-16) have been isolated from the roots of Ferula ferulaeoides (Steud.) Korov. Their structures were established by comprehensive spectroscopic analysis. The biosynthetic pathways leading to these compounds were proposed. The cytotoxicity of all these isolates against HepG2, MCF-7, and C6 cancer cell lines was evaluated and compound 7 displayed the highest potency against HepG2, MCF-7, and C6 with IC50 values 39.9 μM, 37.7 μM, and 16.0 μM, respectively. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Synthesis and Evaluation of Substituted Chroman-4-one and Chromone Derivatives as Sirtuin 2-Selective Inhibitors

    Science.gov (United States)

    2012-01-01

    A series of substituted chromone/chroman-4-one derivatives has been synthesized and evaluated as novel inhibitors of SIRT2, an enzyme involved in aging-related diseases, e.g., neurodegenerative disorders. The analogues were efficiently synthesized in a one-step procedure including a base-mediated aldol condensation using microwave irradiation. The most potent compounds, with inhibitory concentrations in the low micromolar range, were substituted in the 2-, 6-, and 8-positions. Larger, electron-withdrawing substituents in the 6- and 8-positions were favorable. The most potent inhibitor of SIRT2 was 6,8-dibromo-2-pentylchroman-4-one with an IC50 of 1.5 μM. The synthesized compounds show high selectivity toward SIRT2 over SIRT1 and SIRT3 and represent an important starting point for the development of novel SIRT2 inhibitors. PMID:22746324

  20. Actions of lyotropic anions on the mechanical properties of fast and slow twitch rat muscles at different temperatures.

    Science.gov (United States)

    Wondmikun, Y; Soukup, T; Asmussen, G

    2003-01-01

    The effects of lyotropic (swelling) anions (Cl(-), Br(-), NO(3)(-) and I(-)) on contractile properties of fast-twitch extensor digitorum longus (EDL) and slow-twitch soleus (SOL) muscles were investigated in vitro at 20 degrees C and 35 degrees C. Isolated muscles bathed in anionic Tyrode solution were stimulated directly and isometric single twitches and fused tetanic contractions were recorded. In a Cl(-)Tyrode solution a decrease of the bathing temperature led to a cold potentiation of the twitch tension (P(t)) in EDL muscles, however, to a cold depression in SOL muscles, in both muscles combined with a prolongation of contraction (CT) and half relaxation (HRT) times. The extent and order of the potentiating effect of lyotropic anions on the P(t), CT and HRT in EDL and SOL were quite similar and increased in the order: Cl(-)twitch-tetanus ratio (TTR) was increased in NO(3)(-) and I(-)solutions. All effects of the anions were rapidly and completely reversed in both muscles when the test solution was replaced by the normal one. The temperature decrease caused no significant alteration in the potentiation capacity of the anions or in the kinetics of their action and reversibility.

  1. Crystallization and preliminary crystallographic analysis of a novel plant type III polyketide synthase that produces pentaketide chromone

    Energy Technology Data Exchange (ETDEWEB)

    Morita, Hiroyuki [Mitsubishi Kagaku Institute of Life Sciences (MITILS), 11 Minamiooya, Machida, Tokyo 194-8511 (Japan); Kondo, Shin [ZOEGENE Corporation, 1000 Kamoshida, Aoba, Yokohama, Kanagawa 227-8502 (Japan); Abe, Tsuyoshi; Noguchi, Hiroshi [School of Pharmaceutical Sciences and the COE21 Program, University of Shizuoka, Shizuoka 422-8526 (Japan); Sugio, Shigetoshi, E-mail: ssugio@rc.m-kagaku.co.jp [ZOEGENE Corporation, 1000 Kamoshida, Aoba, Yokohama, Kanagawa 227-8502 (Japan); Abe, Ikuro, E-mail: ssugio@rc.m-kagaku.co.jp [School of Pharmaceutical Sciences and the COE21 Program, University of Shizuoka, Shizuoka 422-8526 (Japan); PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan); Kohno, Toshiyuki, E-mail: ssugio@rc.m-kagaku.co.jp [Mitsubishi Kagaku Institute of Life Sciences (MITILS), 11 Minamiooya, Machida, Tokyo 194-8511 (Japan)

    2006-09-01

    Pentaketide chromone synthase from A. arborescens has been overexpressed in E. coli, purified and crystallized. Diffraction data have been collected to 1.6 Å. Pentaketide chromone synthase (PCS) from Aloe arborescens is a novel plant-specific type III polyketide synthase that catalyzes the formation of 5,7-dihydroxy-2-methylchromone from five molecules of malonyl-CoA. Recombinant PCS expressed in Escherichia coli was crystallized by the hanging-drop vapour-diffusion method. The crystals belonged to space group P2{sub 1}, with unit-cell parameters a = 73.2, b = 88.4, c = 70.0 Å, α = γ = 90.0, β = 95.6°. Diffraction data were collected to 1.6 Å resolution using synchrotron radiation at BL24XU of SPring-8.

  2. Controllable Rh(III)-Catalyzed Annulation between Salicylaldehydes and Diazo Compounds: Divergent Synthesis of Chromones and Benzofurans.

    Science.gov (United States)

    Sun, Peng; Gao, Shang; Yang, Chi; Guo, Songjin; Lin, Aijun; Yao, Hequan

    2016-12-16

    A Rh(III)-catalyzed annulation between salicylaldehydes and diazo compounds with controllable chemoselectivity is described. AgNTf2 favored benzofurans via a tandem C-H activation/decarbonylation/annulation process, while AcOH led to chromones through a C-H activation/annulation pathway. The reaction exhibited good functional group tolerance and scalability. Moreover, only a single regioisomer of benzofuran was obtained due to the in situ decarbonylation orientation effect.

  3. Synthesis, Leishmanicidal and Cytotoxic Activity of Triclosan-Chalcone, Triclosan-Chromone and Triclosan-Coumarin Hybrids

    OpenAIRE

    Elver Otero; Sebastián Vergara; Robledo, Sara M.; Wilson Cardona; Miguel Carda; Vélez,Ivan D; Carlos Rojas; Felipe Otálvaro

    2014-01-01

    Twelve hybrids derived from triclosan were obtained via Williamson etherification of O-triclosan alkyl bromide plus chalcone and O-coumarin or O-chromone alkyl bromide plus triclosan, respectively. Structures of the products were elucidated by spectroscopic analysis. The synthesized compounds were evaluated for antileishmanial activity against L. (V) panamensis amastigotes. Cytotoxic activity was also evaluated against mammalian U-937 cells. Compounds 7–9 and 17, were active against Leishmani...

  4. Synthesis and Liquid Crystals Properties of α-Methylated Galactosides

    Science.gov (United States)

    Rodzi, N. Z. B. M.; Heidelberg, T.; Hashim, R.; Sugimura, A.; Minamikawa, H.

    Due to the amphiphilicity nature of glycolipids, some are known to exhibits liquid crystals phases both in thermotropic and lyotropic phases. Six different glycolipids have been synthesized using three steps process and their structures have been characterized by 1H-NMR and 13C-NMR in acetylated and deacytelated forms. Their liquid crystals properties were studied using optical polarising microscopy (OPM) and differential scanning calorimetry (DSC). The effect of α-methylated tails is comparedwith those of the straight chain glycolipids. The epimeric effect of the hydroxyl group at the C-4 of the sugar group was also commented.

  5. Chiral Liquid Crystals: Structures, Phases, Effects

    Directory of Open Access Journals (Sweden)

    Ingo Dierking

    2014-06-01

    Full Text Available The introduction of chirality, i.e., the lack of mirror symmetry, has a profound effect on liquid crystals, not only on the molecular scale but also on the supermolecular scale and phase. I review these effects, which are related to the formation of supermolecular helicity, the occurrence of novel thermodynamic phases, as well as electro-optic effects which can only be observed in chiral liquid crystalline materials. In particular, I will discuss the formation of helical superstructures in cholesteric, Twist Grain Boundary and ferroelectric phases. As examples for the occurrence of novel phases the Blue Phases and Twist Grain Boundary phases are introduced. Chirality related effects are demonstrated through the occurrence of ferroelectricity in both thermotropic as well as lyotropic liquid crystals. Lack of mirror symmetry is also discussed briefly for some biopolymers such as cellulose and DNA, together with its influence on liquid crystalline behavior.

  6. Solid State Structure and Lyotropic Mesomorphism of Rare-Earth Trisdodecylsulphates in the Water-Ethylene Glycol System

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The phase behaviour of lanthanide(Ⅲ) dodecylsulphates, Ln(C12H25SO4)3, by thermo-optical microscopy using Lawrence penetration technique was investigated. The lyotropic phase behaviour of lanthanide(Ⅲ) dodecylsulphates in ethylene glycol water in mixtures hereof, depends on the composition of the solvent. For pure ethylene glycol and mixtures of ethylene glycol and water three different mesophases are formed, i.e. a lamellar, a cubic and a hexagonal phase, whereas when water is used as solvent no cubic phase is formed. The size of the lanthanide ion has no influence on the mesomorphism of these metallomesogens, although the smaller the lanthanide ion the lower the solubility.

  7. 5-Hydroxy-2-(2-phenylethyl)chromone (5-HPEC): a novel non-nitrogenous ligand for 5-HT2B receptor.

    Science.gov (United States)

    Williams, Dwight A; Zaidi, Saheem A; Zhang, Yan

    2014-03-15

    Chromones are a class of natural products found in almost every known terrestrial plant with over 4000 naturally occurring derivatives having been isolated and structurally elucidated. Recently, 5-hydroxy-2-(2-phenylethyl)chromone (5-HPEC), isolated from Imperata cylindrical, showed neuroprotective activity against glutamate induced excitotoxicity in primary cultures of rat cortical cells. In comparison to other naturally occurring neuroprotective chromones, 5-HPEC contains fewer hydroxyl groups. Here we report our most recent characterization on this interesting natural product against a number of CNS receptors for the purpose to identify the potential molecular targets that may be related to its biological activity. Based on our studies, including radiobinding assays, calcium flux functional assays and molecular modeling studies, 5-HPEC may represent a type of novel nonnitrogenous ligands to the 5-HT2B receptor. Published by Elsevier Ltd.

  8. Ferrocenyl and dicobalt hexacarbonyl chromones--new organometallics inducing oxidative stress and arresting human cancer cells in G2/M phase.

    Science.gov (United States)

    Kowalski, Konrad; Hikisz, Paweł; Szczupak, Łukasz; Therrien, Bruno; Koceva-Chyła, Aneta

    2014-06-23

    The straightforward syntheses of four new ferrocenyl and dicobalt hexacarbonyl chromones are presented. The redox behavior of the novel metallo-chromones has been examined by cyclic voltammetry (CV), revealing a reversible behavior of the ferrocenyl groups, while the dicobalt hexacarbonyl derivatives show irreversible oxidation. The anticancer activity of the products has been evaluated against hepatocellular carcinoma (Hep G2), ER+ (MCF-7) and ER- (MDA-MB-231) breast adenocarcinoma, and leukemic (CCRF-CEM) human cancer cell lines. The mechanism of action for the most active complexes has been investigated and it seems to involve oxidative stress and apoptosis induction. Moreover, the results show that the investigated metallo-chromones generate damage to DNA and arrest the cell cycle in G2/M phase. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  9. Formation of α-keto alkyl radical in the photoreduction of chromone as studied by the laser photolysis—ESR technique

    Science.gov (United States)

    Igarashi, Masatoshi; Sakaguchi, Yoshio; Hayashi, Hisaharu; I'Haya, Yasumasa J.

    1991-06-01

    In the photochemical hydrogen abstraction reactions of chromone in 2-propanol at room temperature, beside its ketyl radical, the α-keto alkyl radical from chromone was observed, with the aid of the time-resolved electron spin resonance technique. When tri- n-butylin hydride was used as a hydrogen donor, the α-keto alkyl radical was produced predominantly from the lowest ππ* triplet state. The formation of such a non-ketyl radical in the hydrogen abstraction reaction with both of the hydrogen donors indicates the popularity of the hydrogen abstraction reactions from the ππ* triplet state of aromatic carbonyl compounds.

  10. Ru(II)-Catalyzed Site-Selective Hydroxylation of Flavone and Chromone Derivatives: The Importance of the 5-Hydroxyl Motif for the Inhibition of Aurora Kinases.

    Science.gov (United States)

    Kim, Kiho; Choe, Hyeonjeong; Jeong, Yujeong; Lee, Jun Hee; Hong, Sungwoo

    2015-05-15

    An efficient protocol for Ru(II)-catalyzed direct C-H oxygenation of a broad range of flavone and chromone substrates was developed. This convenient and powerful synthetic tool allows for the rapid installation of the hydroxyl group into the flavone, chromone, and other related scaffolds and opens the way for analog synthesis of highly potent Aurora kinase inhibitors. The molecular docking simulations indicate that the formation of bidentate H-bonding patterns in the hinge regions between the 5-hydroxyflavonoids and Ala213 was the significant binding force, which is consistent with experimental and computational findings.

  11. Rare Chromones from a Fungal Mutant of the Marine-Derived Penicillium purpurogenum G59.

    Science.gov (United States)

    Xia, Ming-Wen; Cui, Cheng-Bin; Li, Chang-Wei; Wu, Chang-Jing; Peng, Ji-Xing; Li, De-Hai

    2015-08-18

    Three new and rare chromones, named epiremisporine B (2), epiremisporine B1 (3) and isoconiochaetone C (4), along with three known remisporine B (1), coniochaetone A (5) and methyl 8-hydroxy-6-methyl-9-oxo-9H-xanthene-1-carboxylate (6) were isolated from a mutant from the diethyl sulfate (DES) mutagenesis of a marine-derived Penicillium purpurogenum G59. The structures of 2-4 including the absolute configurations were determined by spectroscopic methods, especially by NMR analysis and electronic circular dichroism (ECD) experiments in conjunction with calculations. The absolute configuration of the known remisporine B (1) was determined for the first time. Compounds 2 and 3 have a rare feature that has only been reported in one example so far. The compounds 1-6 were evaluated for their cytotoxicity against several human cancer cell lines. The present work explored the great potential of our previous DES mutagenesis strategy for activating silent fungal pathways, which has accelerated the discovery of new bioactive compounds.

  12. Anticancer and Antibacterial Activity Studies of Gold(I)-Alkynyl Chromones.

    Science.gov (United States)

    Hikisz, Paweł; Szczupak, Łukasz; Koceva-Chyła, Aneta; Gu Spiel, Adam; Oehninger, Luciano; Ott, Ingo; Therrien, Bruno; Solecka, Jolanta; Kowalski, Konrad

    2015-10-30

    Three gold(I) complexes of alkynyl chromones were synthesized and characterized. The single-crystal X-ray structure analysis of a dinuclear compound and of a flavone derivative exhibit a typical d10 gold(I)-alkynyl linear arrangement. All complexes were evaluated as anticancer and antibacterial agents against four human cancer cell lines and four pathogenic bacterial strains. All compounds show antiproliferative activity at lower micromolar range concentrations. Complex 4 showed a broad activity profile, being more active than the reference drug auranofin against HepG2, MCF-7 and CCRF-CEM cancer cells. The cellular uptake into MCF-7 cells of the investigated complexes was measured by atomic absorption spectroscopy (AAS). These measurements showed a positive correlation between an increased cellular gold content and the incubation time of the complexes. Unexpectedly an opposite effect was observed for the most active compound. Biological assays revealed various molecular mechanisms for these compounds, comprising: (i) thioredoxin reductase (TrxR) inhibition, (ii) caspases-9 and -3 activation; (iii) DNA damaging activity and (iv) cell cycle disturbance. The gold(I) complexes were also bactericidal against Gram-positive methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) bacterial strains, while showing no activity against the Gram-negative Escherichia coli bacterial strain.

  13. Chroman-4-one- and chromone-based sirtuin 2 inhibitors with antiproliferative properties in cancer cells.

    Science.gov (United States)

    Seifert, Tina; Malo, Marcus; Kokkola, Tarja; Engen, Karin; Fridén-Saxin, Maria; Wallén, Erik A A; Lahtela-Kakkonen, Maija; Jarho, Elina M; Luthman, Kristina

    2014-12-11

    Sirtuins (SIRTs) catalyze the NAD(+)-dependent deacetylation of N(ε)-acetyl lysines on various protein substrates. SIRTs are interesting drug targets as they are considered to be related to important pathologies such as inflammation and aging-associated diseases. We have previously shown that chroman-4-ones act as potent and selective inhibitors of SIRT2. Herein we report novel chroman-4-one and chromone-based SIRT2 inhibitors containing various heterofunctionalities to improve pharmacokinetic properties. The compounds retained both high SIRT2 selectivity and potent inhibitory activity. Two compounds were tested for their antiproliferative effects in breast cancer (MCF-7) and lung carcinoma (A549) cell lines. Both compounds showed antiproliferative effects correlating with their SIRT2 inhibition potency. They also increased the acetylation level of α-tubulin, indicating that SIRT2 is likely to be the target in cancer cells. A binding mode of the inhibitors that is consistent with the SAR data was proposed based on a homology model of SIRT2.

  14. Rare Chromones from a Fungal Mutant of the Marine-Derived Penicillium purpurogenum G59

    Directory of Open Access Journals (Sweden)

    Ming-Wen Xia

    2015-08-01

    Full Text Available Three new and rare chromones, named epiremisporine B (2, epiremisporine B1 (3 and isoconiochaetone C (4, along with three known remisporine B (1, coniochaetone A (5 and methyl 8-hydroxy-6-methyl-9-oxo-9H-xanthene-1-carboxylate (6 were isolated from a mutant from the diethyl sulfate (DES mutagenesis of a marine-derived Penicillium purpurogenum G59. The structures of 2–4 including the absolute configurations were determined by spectroscopic methods, especially by NMR analysis and electronic circular dichroism (ECD experiments in conjunction with calculations. The absolute configuration of the known remisporine B (1 was determined for the first time. Compounds 2 and 3 have a rare feature that has only been reported in one example so far. The compounds 1–6 were evaluated for their cytotoxicity against several human cancer cell lines. The present work explored the great potential of our previous DES mutagenesis strategy for activating silent fungal pathways, which has accelerated the discovery of new bioactive compounds.

  15. Synthesis, characterization, DNA-binding studies and acetylcholinesterase inhibition activity of new 3-formyl chromone derivatives.

    Science.gov (United States)

    Parveen, Mehtab; Malla, Ali Mohammed; Yaseen, Zahid; Ali, Akhtar; Alam, Mahboob

    2014-01-05

    A series of new substituted 3-formyl chromone derivatives (4-6) were synthesized by one step reaction methodology by knoevenagel condensation, structurally similar to known bisintercalators. The new compounds were characterized by IR, (1)H NMR, (13)C NMR, MS and analytical data. The in vitro DNA binding profile of compounds (4-6) was carried out by absorption, fluorescence and viscosity measurements. It was found that synthesized compounds, especially compound 6 (evident from binding constant value) bind strongly with calf thymus DNA, presumably via an intercalation mode. Additionally, molecular docking studies of compounds (4-6) were carried out with B-DNA (PDBID: 1BNA) which revealed that partial intercalative mode of mechanism is operational in synthesized compounds (4-6) with CT-DNA. The binding constants evaluated from fluorescence spectroscopy of compounds with CT-DNA follows the order compound 6>compound 5>compound 4. All the compounds (4-6) were screened for acetylcholinesterase inhibition assay. It can be inferred from data, that compound (6) showed potent AChE inhibition having IC50=0.27μM, almost in vicinity to reference drug Tacrine (IC50=0.19μM). Copyright © 2013 Elsevier B.V. All rights reserved.

  16. A chromone Schiff-base as Al(III) selective fluorescent and colorimetric chemosensor

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Long; Qin, Jing-can; Li, Tian-rong; Wang, Bao-dui; Yang, Zheng-yin, E-mail: yangzy@lzu.edu.cn

    2014-11-15

    A novel and simple chromone Schiff-base receptor 7-methoxychromone-3-carbaldehyde-(indole-2-formyl) hydrazone (MCIH) was prepared. Among the various metal ions, only Al{sup 3+} induces the fluorescence enhancement and results in “OFF–ON” type sensing with excellent selectivity and high sensitivity in ethanol system. Upon binding of Al{sup 3+}, a significant fluorescence enhancement with an “OFF–ON” ratio over 500-fold was triggered and it features visible light excitation (423 nm) and emission (507 nm) profiles. However, other metal ions had no such significant effect on the fluorescence. Also, MCIH can severe as a highly selective chemodosimeter for Al{sup 3+} with “naked-eye” detection, which is easily observed from colorless to yellow–green. The detection limit of MCIH for Al{sup 3+} detection was as low as 5×10{sup −8} M level. - Highlights: • An easy-to-make colorimetric and fluorescent sensor for Al{sup 3+} was developed. • The sensor exhibits higher selectivity and sensitivity for Al{sup 3+} than other metal ions. • Al{sup 3+} resulted in an instant color change of MCIH from colorless to yellow–green. • The Al{sup 3+} detection limit reaching at 5×10{sup −8} M level in ethanol. • This sensor features visible light excitation (423 nm) and emission (507 nm) profiles.

  17. Living liquid crystals

    Science.gov (United States)

    Zhou, Shuang; Sokolov, Andrey; Lavrentovich, Oleg D.; Aranson, Igor S.

    2014-01-01

    Collective motion of self-propelled organisms or synthetic particles, often termed “active fluid,” has attracted enormous attention in the broad scientific community because of its fundamentally nonequilibrium nature. Energy input and interactions among the moving units and the medium lead to complex dynamics. Here, we introduce a class of active matter––living liquid crystals (LLCs)––that combines living swimming bacteria with a lyotropic liquid crystal. The physical properties of LLCs can be controlled by the amount of oxygen available to bacteria, by concentration of ingredients, or by temperature. Our studies reveal a wealth of intriguing dynamic phenomena, caused by the coupling between the activity-triggered flow and long-range orientational order of the medium. Among these are (i) nonlinear trajectories of bacterial motion guided by nonuniform director, (ii) local melting of the liquid crystal caused by the bacteria-produced shear flows, (iii) activity-triggered transition from a nonflowing uniform state into a flowing one-dimensional periodic pattern and its evolution into a turbulent array of topological defects, and (iv) birefringence-enabled visualization of microflow generated by the nanometers-thick bacterial flagella. Unlike their isotropic counterpart, the LLCs show collective dynamic effects at very low volume fraction of bacteria, on the order of 0.2%. Our work suggests an unorthodox design concept to control and manipulate the dynamic behavior of soft active matter and opens the door for potential biosensing and biomedical applications. PMID:24474746

  18. Nanoparticles in ionic liquids: interactions and organization.

    Science.gov (United States)

    He, Zhiqi; Alexandridis, Paschalis

    2015-07-28

    Ionic liquids (ILs), defined as low-melting organic salts, are a novel class of compounds with unique properties and a combinatorially great chemical diversity. Ionic liquids are utilized as synthesis and dispersion media for nanoparticles as well as for surface functionalization. Ionic liquid and nanoparticle hybrid systems are governed by a combined effect of several intermolecular interactions between their constituents. For each interaction, including van der Waals, electrostatic, structural, solvophobic, steric, and hydrogen bonding, the characterization and quantitative calculation methods together with factors affecting these interactions are reviewed here. Various self-organized structures based on nanoparticles in ionic liquids are generated as a result of a balance of these intermolecular interactions. These structures, including colloidal glasses and gels, lyotropic liquid crystals, nanoparticle-stabilized ionic liquid-containing emulsions, ionic liquid surface-functionalized nanoparticles, and nanoscale ionic materials, possess properties of both ionic liquids and nanoparticles, which render them useful as novel materials especially in electrochemical and catalysis applications. This review of the interactions within nanoparticle dispersions in ionic liquids and of the structure of nanoparticle and ionic liquid hybrids provides guidance on the rational design of novel ionic liquid-based materials, enabling applications in broad areas.

  19. Design, synthesis and docking studies of novel thienopyrimidine derivatives bearing chromone moiety as mTOR/PI3Kα inhibitors.

    Science.gov (United States)

    Zhu, Wufu; Chen, Chen; Sun, Chengyu; Xu, Shan; Wu, Chunjiang; Lei, Fei; Xia, Hui; Tu, Qidong; Zheng, Pengwu

    2015-03-26

    Two series of thienopyrimidine derivatives (10a-k, 16a-j) bearing chromone moiety were designed and synthesized. All the compounds were evaluated for inhibitory activity against mTOR kinase at a concentration of 10uM. Four selected compounds were further evaluated for the IC50 values against mTOR kinase, PI3Kα kinase and two cancer cell lines. Some of the target compounds exhibited moderate to excellent mTOR/PI3Kα kinase inhibitory activity and cytotoxicity. The most promising compound 16i showed good inhibitory activity against mTOR/PI3Kα kinase and good antitumor potency for H460 and PC-3 cell lines with IC50 values of 0.16 ± 0.03 μM, 2.35 ± 0.19 μM, 1.20 ± 0.23 μM and 0.85 ± 0.04 μM, which were 8.6, >5, 7.9 and 19.1 times more active than compound I (1.37 ± 0.07 μM, >10 μM, 9.52 ± 0.29 μM, 16.27 ± 0.54 μM), respectively. Structure-activity relationships (SARs) and docking studies indicated that the chromone moiety is necessary for the potent antitumor activity and cytotoxicity of these compounds. Substitution of the chromone moiety at the 6-position has a significant impact to the inhibitory activity, in particular a carboxylic acid group, produced the best potency. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  20. Anomalous spin polarization in the photoreduction of chromone-2-carboxylic acid with alcohol induced by hydrochloric acid

    Science.gov (United States)

    Ohara, Keishi; Mukai, Kazuo

    2000-02-01

    The addition effect of hydrochloric acid (HCl) on the photoreduction of chromone-2-carboxylic acid (CRCA) is studied by time-resolved EPR. The EPR lines of CRCA ketyl radical show an enhanced absorption in the presence of HCl, while without HCl these show an emissive character. On the other hand, the lines of the CRCA alkyl type radical show an emissive character whether HCl is included or not. The simultaneous reactions of the closely-lying two excited triplet states (T 1 and T 2) of CRCA may induce the above anomalous CIDEP behavior.

  1. Liquid crystal of nanocellulose whiskers' grafted with acrylamide

    Institute of Scientific and Technical Information of China (English)

    Jie Yang; Dai Yong Ye

    2012-01-01

    12% acrylamide (AM) was grafted onto the surface of nanocellulose whiskers (NCW),which was self-assembled to be the chiral nematic suspension at 3% content.The acrylamide grafted NCW (AM-g-NCW) was characterized with Fourier Transform Infrared Spectroscopy (FTIR).The grafting ratio was measured by elemental analysis.The degrees of crystallinity of the AM-g-NCW were measured by X-ray diffraction (XRD).The liquid crystalline properties of the AM-g-NCW were investigated by the polarizing optical microscopy (POM).The AM-g-NCW was found to self-assembly to be a lyotropic state.

  2. Inhibition of volume-activated chloride currents in endothelial cells by chromones.

    Science.gov (United States)

    Heinke, S.; Szücs, G.; Norris, A.; Droogmans, G.; Nilius, B.

    1995-01-01

    1. We have studied the effects of the reported chloride channel blocker, sodium cromoglycate, on volume-activated Cl- currents in endothelial cells from bovine pulmonary artery by means of the whole-cell patch clamp technique. Cl- currents were activated by challenging the cells with a hypotonic extracellular solution of 60% of the normal osmolarity. 2. Half maximal activation of the current at +95 mV occurred after exposure of the cells for 148 +/- 10 s (n = 6) to hypotonic solution (HTS). At the same membrane potential but in the presence of 100 microM sodium cromoglycate (disodium-1,3-bis (2'-carboxylate-chromone-5'-yloxy)-2-hydroxy-propane) activation was delayed (253 +/- 25 s, n = 6) and the maximal current amplitude was reduced to 63 +/- 7% of the control (n = 13). 3. In comparison, an equimolar concentration of NPPB (5-nitro-2(3-phenyl) propylamino-benzoic acid), another Cl- channel blocker, completely blocked the volume-activated current in less than 20 s. 4. Sodium cromoglycate, applied at the time when the HTS-induced current was completely activated, dose-dependently inhibited this current with a concentration for half maximal inhibition of 310 +/- 70 microM. Data for nedocromil sodium were not significantly different from those for sodium cromoglycate. 5. Sodium cromoglycate, loaded into the endothelial cells via the patch pipette in ruptured patches, resulted in a decline of the HTS activated current with a time course that was compatible with diffusion of the compound from the pipette into the cell.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8564197

  3. Synthesis of chromone, quinolone, and benzoxazinone sulfonamide nucleosides as conformationally constrained inhibitors of adenylating enzymes required for siderophore biosynthesis.

    Science.gov (United States)

    Engelhart, Curtis A; Aldrich, Courtney C

    2013-08-02

    MbtA catalyzes the first committed step of mycobactin biosynthesis in Mycobacterium tuberculosis (Mtb) and is responsible for the incorporation of salicylic acid into the mycobactin siderophores. 5'-O-[N-(Salicyl)sulfamoyl]adenosine (Sal-AMS) is an extremely potent nucleoside inhibitor of MbtA that possesses excellent activity against whole-cell Mtb but suffers from poor bioavailability. In an effort to improve the bioavailability, we have designed four conformationally constrained analogues of Sal-AMS that remove two rotatable bonds and the ionized sulfamate group on the basis of computational and structural studies. Herein we describe the synthesis, biochemical, and microbiological evaluation of chromone-, quinolone-, and benzoxazinone-3-sulfonamide derivatives of Sal-AMS. We developed new chemistry to assemble these three heterocycles from common β-ketosulfonamide intermediates. The synthesis of the chromone- and quinolone-3-sulfonamide intermediates features formylation of a β-ketosulfonamide employing dimethylformamide dimethyl acetal to afford an enaminone that can react intramolecularly with a phenol or intermolecularly with a primary amine via addition-elimination reaction(s). The benzoxazinone-3-sulfonamide was prepared by nitrosation of a β-ketosulfonamide followed by intramolecular nucleophilic aromatic substitution. Mitsunobu coupling of these bicyclic sulfonamides with a protected adenosine derivative followed by global deprotection provides a concise synthesis of the respective inhibitors.

  4. A Chromone-Derived Schiff-Base Ligand as Al(3+) "Turn on" Fluorescent Sensor: Synthesis and Spectroscopic Properties.

    Science.gov (United States)

    Li, Chao-rui; Qin, Jing-can; Wang, Bao-dui; Fan, Long; Yan, Jun; Yang, Zheng-yin

    2016-01-01

    In this study, a novel chromone-derived Schiff-base ligand called 6-Hydroxy-3-formylchromone (2'-furan formyl) hydrazone (HCFH) has been designed and synthesized as a "turn on" fluorescent sensor for Al(3+). This sensor HCFH showed high selectivity and sensitivity towards Al(3+) over other metal ions investigated, and most metal ions had nearly no influences on the fluorescence response of HCFH to Al(3+). Additionally, the significant enhancement by about 171-fold in fluorescence emission intensity at 502 nm was observed in the presence of Al(3+) in ethanol, and it was due to the chelation-enhanced fluorescence (CHEF) effect upon complexation of HCFH with Al(3+) which inhibited the photoinduced electron transfer (PET) phenomenon from the Schiff-base nitrogen atom to chromone group. Moreover, this sensor formed a 1 : 1 complex with Al(3+) and the fluorescence response of HCFH to Al(3+) was nearly completed within 1 min. Thus, this sensor HCFH could be used to detect and recognize Al(3+) for real-time detection.

  5. Ligand-based CoMFA and CoMSIA studies on chromone derivatives as radical scavengers.

    Science.gov (United States)

    Phosrithong, Narumol; Ungwitayatorn, Jiraporn

    2013-08-01

    The antioxidant activity for a series of chromone compounds, evaluated by DPPH free radical scavenging assay, were subjected to 3D-QSAR studies using comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA). All 48 chromone derivatives were geometry optimized by AM1 and HF/6-31G(*) calculations. The CoMFA and CoMSIA results were compared between different alignment strategies. The best CoMFA model obtained from HF/6-31G(*) optimization with field fit alignment gave cross-validated r(2) (q(2))=0.821, noncross-validated r(2)=0.987, S=0.095, and F=388.255. The best CoMSIA model derived from AM1 optimized structures and superimposition alignment gave q(2)=0.876, noncross-validated r(2)=0.976, S=0.129, and F=208.073, including electrostatic, hydrophobic, hydrogen bond donor and acceptor fields. The contour maps provide the fruitful structure-radical scavenging activity relationships which are useful for designing new compounds with higher activity. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. Microwave-assisted Diels-Alder reaction of 1,3,3-trimethyl-2-vinyl-1-cyclohexene with chromones An expeditious approach to analogues of the puupehenone group of marine diterpenoids and kampanols

    National Research Council Canada - National Science Library

    Ramana, M. M.V; Kamble, Rajesh M

    2010-01-01

    A rapid assembly of the tetracyclic core of marine diterpenoids related to puupehenone and kampanols by a Diels-Alder reaction of 1,3,3-trimethyl-2-vinyl-1-cyclohexene with chromones under microwave...

  7. GYF-21, an Epoxide 2-(2-Phenethyl)-Chromone Derivative, Suppresses Innate and Adaptive Immunity via Inhibiting STAT1/3 and NF-κB Signaling Pathways

    National Research Council Canada - National Science Library

    Ran Guo; Yun-Fang Zhao; Jun Li; Yu-Fan Gu; Hui-Xia Huo; Shan-Shan Li; Yue-Lin Song; Zhi-Xiang Zhu; Peng-Fei Tu

    2017-01-01

    .... In the present study, we investigated the inhibitory effects of GYF-21, an epoxide 2-(2-phenethyl)-chromone derivative isolated from Chinese agarwood, on innate and adaptive immunity for revealing its potential to treat multiple sclerosis...

  8. Synthesis and properties of lyotropic poly(amide-block-aramid) copolymers

    NARCIS (Netherlands)

    De Ruijter, C.

    2006-01-01

    This thesis describes the synthesis and properties of liquid crystalline block copolymers comprised of alternating rigid and flexible blocks for the preparation of self-reinforcing materials. The incentive for this work was the expectation that the rigid segments would phase separate on a microscopi

  9. Dielectric spectroscopy of isotropic liquids and liquid crystal phases with dispersed graphene oxide

    Science.gov (United States)

    Al-Zangana, Shakhawan; Iliut, Maria; Boran, Gökçen; Turner, Michael; Vijayaraghavan, Aravind; Dierking, Ingo

    2016-08-01

    Graphene oxide (GO) flakes of different sizes were prepared and dispersed in isotropic and nematic (anisotropic) fluid media. The dielectric relaxation behaviour of GO-dispersions was examined for a wide temperature (25-60 oC) and frequency range (100 Hz-2 MHz). The mixtures containing GO flakes exhibited varying dielectric relaxation processes, depending on the size of the flakes and the elastic properties of the dispersant fluid. Relaxation frequencies of the GO doped isotropic media, such as isopropanol IPA, were observed to be much lower than the GO doped thermotropic nematic medium 5CB. It is anticipated that the slow relaxation frequencies (~10 kHz) could be resulting from the relaxation modes of the GO flakes while the fast relaxation frequencies (~100 kHz) could indicate strongly slowed down molecular modes of the nematogenic molecules, which are anchored to the GO flakes via dispersion interactions. The relaxation frequencies decreased as the size of the GO flakes in the isotropic solvent was increased. Polarizing microscopy showed that GO flakes with a mean diameter of 10 μm, dispersed in water, formed a lyotropic nematic liquid crystal phase. This lyotropic nematic exhibited the slowest dielectric relaxation process, with relaxation frequencies in the order of 2 kHz, as compared to the GO-isotropic suspension and the GO-doped 5CB.

  10. Design, synthesis and evaluation of chromone-2-carboxamido-alkylbenzylamines as multifunctional agents for the treatment of Alzheimer's disease.

    Science.gov (United States)

    Liu, Qiang; Qiang, Xiaoming; Li, Yan; Sang, Zhipei; Li, Yuxing; Tan, Zhenghuai; Deng, Yong

    2015-03-01

    A series of chromone-2-carboxamido-alkylbenzylamines were designed, synthesized and evaluated as multifunctional agents for the treatment of Alzheimer's disease (AD). The results showed that most of these compounds exhibited good multifunctional activities. Among them, compound 49 displayed excellent inhibitory potency toward acetylcholinesterase (AChE), moderate anti-oxidative activity, selective biometal chelating, and possessed good inhibitory effects on self-induced and Cu(2+)-induced Aβ aggregation. Both kinetic analysis of AChE inhibition and molecular modeling study indicated that 49 was a mixed-type inhibitor, binding simultaneously to the catalytic active site and peripheral anionic site of AChE. These results suggested that 49 might be a potential multifunctional agent for AD treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Crystallization and preliminary crystallographic analysis of a novel plant type III polyketide synthase that produces pentaketide chromone

    Science.gov (United States)

    Morita, Hiroyuki; Kondo, Shin; Abe, Tsuyoshi; Noguchi, Hiroshi; Sugio, Shigetoshi; Abe, Ikuro; Kohno, Toshiyuki

    2006-01-01

    Pentaketide chromone synthase (PCS) from Aloe arborescens is a novel plant-specific type III polyketide synthase that catalyzes the formation of 5,7-dihydroxy-2-methylchromone from five molecules of malonyl-CoA. Recombinant PCS expressed in Escherichia coli was crystallized by the hanging-drop vapour-diffusion method. The crystals belonged to space group P21, with unit-cell parameters a = 73.2, b = 88.4, c = 70.0 Å, α = γ = 90.0, β = 95.6°. Diffraction data were collected to 1.6 Å resolution using synchrotron radiation at BL24XU of SPring-8. PMID:16946474

  12. Swimming bacteria in liquid crystal

    Science.gov (United States)

    Sokolov, Andrey; Zhou, Shuang; Aranson, Igor; Lavrentovich, Oleg

    2014-03-01

    Dynamics of swimming bacteria can be very complex due to the interaction between the bacteria and the fluid, especially when the suspending fluid is non-Newtonian. Placement of swimming bacteria in lyotropic liquid crystal produces a new class of active materials by combining features of two seemingly incompatible constituents: self-propelled live bacteria and ordered liquid crystals. Here we present fundamentally new phenomena caused by the coupling between direction of bacterial swimming, bacteria-triggered flows and director orientations. Locomotion of bacteria may locally reduce the degree of order in liquid crystal or even trigger nematic-isotropic phase transition. Microscopic flows generated by bacterial flagella disturb director orientation. Emerged birefringence patterns allow direct optical observation and quantitative characterization of flagella dynamics. At high concentration of bacteria we observed the emergence of self-organized periodic texture caused by bacteria swimming. Our work sheds new light on self-organization in hybrid bio-mechanical systems and can lead to valuable biomedical applications. Was supported by the US DOE, Office of Basic Energy Sciences, Division of Materials Science and Engineering, under the Contract No. DE AC02-06CH11357.

  13. Characterization and Analysis of 2-(2-Phenylethyl-chromone Derivatives from Agarwood (Aquilaria crassna by Artificial Holing for Different Times

    Directory of Open Access Journals (Sweden)

    Jin Ling Yang

    2016-07-01

    Full Text Available A total of fifty-six chromones, including seven 5,6,7,8-tetrahydro-2-(2-phenylethyl-chromones (THPECs, five 5,6-epoxy-2-(2-phenylethylchromones (EPECs, seven 5,6:7,8-diepoxy-2-(2-phenylethylchromones (DEPECs and thirty-seven 2-(2-phenylethylchromones of the flidersia type (FTPECs, were characterized by HPLC/DAD/ESI/MS/MS in three agarwood samples (from Aquilaria crassna induced by artificial holing with different holing times. The characteristic fragmentation behavior of DEPECs and EPECs, and the methods to distinguish these four types of chromones by MS analysis were described for the first time. In addition, it was found that the relative contents of DEPECs and EPECs were down-regulated, while the relative contents of THPECs and FTPECs were up-regulated for the samples from two, four and five years of the agarwood formation time. However, the relative contents of six most widespread and abundant FTPECs presented roughly upward based on the formation time. These results could be referenced to distinguish different agarwood samples collected from different formation time.

  14. Structure-activity relationships of chromone derivatives toward the mechanism of interaction with and inhibition of breast cancer resistance protein ABCG2.

    Science.gov (United States)

    Winter, Evelyn; Lecerf-Schmidt, Florine; Gozzi, Gustavo; Peres, Basile; Lightbody, Mark; Gauthier, Charlotte; Ozvegy-Laczka, Csilla; Szakacs, Gergely; Sarkadi, Balazs; Creczynski-Pasa, Tânia B; Boumendjel, Ahcène; Di Pietro, Attilio

    2013-12-27

    We recently identified a chromone derivative, 5-(4-bromobenzyloxy)-2-(2-(5-methoxyindolyl)ethyl-1-carbonyl)-4H-chromen-4-one, named here as chromone 1, as a potent, selective, nontoxic, and nontransported inhibitor of ABCG2-mediated drug efflux (Valdameri et al. J. Med. Chem. 2012, 55, 966). We have now synthesized a series of 14 derivatives to study the structure-activity relationships controlling both drug efflux and ATPase activity of ABCG2 and to elucidate their molecular mechanism of interaction and inhibition. It was found that the 4-bromobenzyloxy substituent at position 5 and the methoxyindole are important for both inhibition of mitoxantrone efflux and inhibition of basal ATPase activity. Quite interestingly, methylation of the central amide nitrogen strongly altered the high affinity for ABCG2 and the complete inhibition of mitoxantrone efflux and coupled ATPase activity. These results allowed the identification of a critical central inhibitory moiety of chromones that has never been investigated previously in any series of inhibitors.

  15. Development of multiple QSAR models for consensus predictions and unified mechanistic interpretations of the free-radical scavenging activities of chromone derivatives.

    Science.gov (United States)

    Mitra, Indrani; Saha, Achintya; Roy, Kunal

    2012-05-01

    Antioxidants are important defenders of the human body against nocive free radicals, which are the causative agents of most life-threatening diseases. The immense biomedicinal utility of antioxidants necessitates the development and design of new synthetic antioxidant molecules. The present report deals with the modeling of a series of chromone derivatives, which was done to provide detailed insight into the main structural fragments that impart antioxidant activity to these molecules. Four different quantitative structure-property relationship (QSAR) techniques, namely 3D pharmacophore mapping, comparative molecular similarity indices analysis (CoMSIA 3D-QSAR), hologram QSAR (HQSAR), and group-based QSAR (G-QSAR) techniques, were employed to obtain statistically significant models with encouraging external predictive potentials. Moreover, the visual contribution maps obtained for the different models signify the importance of different structural features in specific regions of the chromone nucleus. Additionally, the G-QSAR models determine the composite influence of pairs of substituent fragments on the overall antioxidant activity profiles of the molecules. Multiple models with different strategies for assessing structure-activity relationships were applied to reach a unified conclusion regarding the antioxidant mechanism and to provide consensus predictions, which are more reliable than values derived from a single model. The structural information obtained from the various QSAR models developed in the present work can thus be effectively utilized to design and predict the activities of new molecules belonging to the class of chromone derivatives.

  16. A comparison of the structures of some 2- and 3-substituted chromone derivatives: a structural study on the importance of the secondary carboxamide backbone for the inhibitory activity of MAO-B

    Directory of Open Access Journals (Sweden)

    Ligia R. Gomes

    2015-11-01

    Full Text Available The crystal structures of the 3-substituted tertiary chromone carboxamide derivative, C17H13NO3, N-methyl-4-oxo-N-phenyl-4H-chromene-3-carboxamide (1, and the chromone carbonyl pyrrolidine derivatives, C14H13NO3, 3-(pyrrolidine-1-carbonyl-4H-chromen-4-one (3 and 2-(pyrrolidine-1-carbonyl-4H-chromen-4-one (4 have been determined. Their structural features are discussed and compared with similar compounds namely with respect to their MAO-B inhibitory activities. The chromone carboxamide presents a –syn conformation with the aromatic rings twisted with respect to each other [the dihedral angle between the mean planes of the chromone system and the exocyclic phenyl ring is 58.48 (8°]. The pyrrolidine derivatives also display a significant twist: the dihedral angles between the chromone system and the best plane formed by the pyrrolidine atoms are 48.9 (2 and 23.97 (12° in (3 and (4, respectively. Compound (3 shows a short C—H...O intramolecular contact forming an S(7 ring. The supramolecular structures for each compound are defined by weak C—H...O hydrogen bonds, which link the molecules into chains and sheets. The Cambridge Structural Database gave 45 hits for compounds with a pyrrolidinecarbonyl group. A simple statistical analysis of their geometric parameters is made in order to compare them with those of the molecules determined in the present work.

  17. Disodium cromoglycate: exploiting its properties as a NMR weak-aligning medium for small organic molecules.

    Science.gov (United States)

    Troche-Pesqueira, Eduardo; Cid, María-Magdalena; Navarro-Vázquez, Armando

    2014-03-28

    Chromonic phases are a family of lyotropic liquid crystals (LC) formed by ionic aromatic mesogens such as disodium cromoglycate (cromolyn), sunset yellow and others. It is well known that chromonic phases are oriented in the presence of external magnetic fields, leading to the observation of anisotropic NMR observables such as quadrupolar splittings or residual dipolar couplings. Despite the fact that the cromolyn nematic LC phase (N) presents important advantages like great homogeneity, small line broadening, and easy sample preparation, it has been scarcely used as a water-compatible NMR orienting medium, in part due to a too strong induced degree of alignment on the guest molecules. However, the use of cromolyn-brine mixtures led to the optimum degree of alignment allowing to record (1)H-(13)C dipolar couplings with good accuracy.

  18. Hierarchical structuring of liquid crystal polymer-Laponite hybrid materials.

    Science.gov (United States)

    Tritschler, Ulrich; Zlotnikov, Igor; Zaslansky, Paul; Aichmayer, Barbara; Fratzl, Peter; Schlaad, Helmut; Cölfen, Helmut

    2013-09-03

    Biomimetic organic-inorganic composite materials were fabricated via one-step self-organization on three hierarchical levels. The organic component was a polyoxazoline with pendent cholesteryl and carboxyl (N-Boc-protected amino acid) side chains that was able to form a chiral nematic lyotropic phase and bind to positively charged inorganic faces of Laponite. The Laponite particles formed a mesocrystalline arrangement within the liquid-crystal (LC) polymer phase upon shearing a viscous dispersion of Laponite nanoparticles and LC polymer in DMF. Complementary analytical and mechanical characterization techniques (AUC, POM, TEM, SEM, SAXS, μCT, and nanoindentation) covering the millimeter, micrometer, and nanometer length scales reveal the hierarchical structures and properties of the composite materials consisting of different ratios of Laponite nanoparticles and liquid-crystalline polymer.

  19. STUDIES ON CRITICAL CONCENTRATION OF LIQUID CRYSTALLINE ETHYLCELLULOSE

    Institute of Scientific and Technical Information of China (English)

    DONG Yanming; ZHANG Shiying

    1996-01-01

    Critical concentrations of lyotropic liquid crystalline ethylcellulose in more than ten cal concentration Ccrit of forming liquid crystal phase decreased with increasing solubility parameter δ of solvent until approaching the δ of polymer. Although the alcohols used as solvents had the same variation rule, the critical concentration values of their solutions were much higher, due to their excessive large hydrogen bond component of δ. The experiments of using mixed solvents which showed good linear relation between Ccrit and δ also proved this rule. A technique of Transmission Optical Analysis was first used to estimate the concentration dependence of critical phase transition temperature Tcrit of EC, and a T-C phase diagram could be drawn.

  20. Improved Cross Validation of a Static Ubiquitin Structure Derived from High Precision Residual Dipolar Couplings Measured in a Drug-Based Liquid Crystalline Phase

    OpenAIRE

    2014-01-01

    The antibiotic squalamine forms a lyotropic liquid crystal at very low concentrations in water (0.3-3.5% w/v), which remains stable over a wide range of temperature (1-40 °C) and pH (4-8). Squalamine is positively charged, and comparison of the alignment of ubiquitin relative to 36 previously reported alignment conditions shows that it differs substantially from most of these, but is closest to liquid crystalline cetyl pyridinium bromide. High precision residual dipolar couplings (RDCs) measu...

  1. Synthesis, Leishmanicidal and Cytotoxic Activity of Triclosan-Chalcone, Triclosan-Chromone and Triclosan-Coumarin Hybrids

    Directory of Open Access Journals (Sweden)

    Elver Otero

    2014-08-01

    Full Text Available Twelve hybrids derived from triclosan were obtained via Williamson etherification of O-triclosan alkyl bromide plus chalcone and O-coumarin or O-chromone alkyl bromide plus triclosan, respectively. Structures of the products were elucidated by spectroscopic analysis. The synthesized compounds were evaluated for antileishmanial activity against L. (V panamensis amastigotes. Cytotoxic activity was also evaluated against mammalian U-937 cells. Compounds 7–9 and 17, were active against Leishmania parasites (EC50 = 9.4; 10.2; 13.5 and 27.5 µg/mL, respectively and showed no toxicity toward mammalian cells (>200 µg/mL. They are potential candidates for antileishmanial drug development. Compounds 25–27, were active and cytotoxic. Further studies using other cell types are needed in order to discriminate whether the toxicity shown by these compounds is against tumor or non-tumor cells. The results indicate that compounds containing small alkyl chains show better selectivity indices. Moreover, Michael acceptor moieties may modify both the leishmanicidal activity and cytotoxicity. Further studies are required to evaluate if the in vitro activity against Leishmania panamensis demonstrated here is also observed in vivo.

  2. Synthesis, leishmanicidal and cytotoxic activity of triclosan-chalcone, triclosan-chromone and triclosan-coumarin hybrids.

    Science.gov (United States)

    Otero, Elver; Vergara, Sebastián; Robledo, Sara M; Cardona, Wilson; Carda, Miguel; Vélez, Ivan D; Rojas, Carlos; Otálvaro, Felipe

    2014-08-28

    Twelve hybrids derived from triclosan were obtained via Williamson etherification of O-triclosan alkyl bromide plus chalcone and O-coumarin or O-chromone alkyl bromide plus triclosan, respectively. Structures of the products were elucidated by spectroscopic analysis. The synthesized compounds were evaluated for antileishmanial activity against L. (V) panamensis amastigotes. Cytotoxic activity was also evaluated against mammalian U-937 cells. Compounds 7-9 and 17, were active against Leishmania parasites (EC50=9.4; 10.2; 13.5 and 27.5 µg/mL, respectively) and showed no toxicity toward mammalian cells (>200 µg/mL). They are potential candidates for antileishmanial drug development. Compounds 25-27, were active and cytotoxic. Further studies using other cell types are needed in order to discriminate whether the toxicity shown by these compounds is against tumor or non-tumor cells. The results indicate that compounds containing small alkyl chains show better selectivity indices. Moreover, Michael acceptor moieties may modify both the leishmanicidal activity and cytotoxicity. Further studies are required to evaluate if the in vitro activity against Leishmania panamensis demonstrated here is also observed in vivo.

  3. Synthesis, spectral characterisation, morphology, biological activity and DNA cleavage studies of metal complexes with chromone Schiff base

    Directory of Open Access Journals (Sweden)

    P. Kavitha

    2016-07-01

    Full Text Available Cu(II, Co(II, Ni(II and Zn(II complexes have been synthesized using 3-((pyridine-2-yliminomethyl-4H-chromen-4-one as a ligand derived from 3-formyl chromone and 2-amino pyridine. All the complexes were characterised by analytical, conductivity, IR, electronic, magnetic, ESR, thermal, powder XRD and SEM studies. The analytical data revealed that the metal to ligand molar ratio is 1:2 in all the complexes. Molar conductivity data indicates that all the complexes are neutral in nature. On the basis of magnetic and electronic spectral data, octahedral geometry is proposed for all the complexes. Thermal behaviour of the synthesized complexes indicates the coordinated and lattice water molecules are present in the complexes. The X-ray diffraction data suggest a triclinic system for all compounds. Different surface morphologies were identified from SEM micrographs. All metal complexes exhibit fluorescence. The antimicrobial and nematicidal activity data show that metal complexes are more potent than the parent ligand. The DNA cleavage activity of the ligand and its metal complexes were observed in the presence of H2O2.

  4. New, highly potent and non-toxic, chromone inhibitors of the human breast cancer resistance protein ABCG2.

    Science.gov (United States)

    Pires, Amanda do Rocio Andrade; Lecerf-Schmidt, Florine; Guragossian, Nathalie; Pazinato, Jaqueline; Gozzi, Gustavo Jabor; Winter, Evelyn; Valdameri, Glaucio; Veale, Alexander; Boumendjel, Ahcène; Di Pietro, Attilio; Pérès, Basile

    2016-10-21

    Breast cancer resistance protein (BCRP/ABCG2) is one of the major transporters involved in the efflux of anticancer compounds, contributing to multidrug resistance (MDR). Inhibition of ABCG2-mediated transport is then considered a promising strategy for overcoming MDR in tumors. We recently identified a chromone derivative, namely MBL-II-141 as a selective ABCG2 inhibitor, with relevant in vivo activity. Here, we report the pharmacomodulation of MBL-II-141, with the aim of identifying key pharmacophoric elements to design more potent selective and non-toxic inhibitors. Through rational structural modifications of MBL-II-141, using simple and affordable chemistry, we obtained highly active and easily-made inhibitors of ABCG2. Among the investigated compounds, derivative 4a, was found to be 3-fold more potent than MBL-II-141. It was similarly efficient as the reference inhibitor Ko143 but with the advantage of a lower intrinsic cytotoxicity, and therefore constitutes the best ABCG2 inhibitor ever reported displaying a very high therapeutic ratio. Copyright © 2016. Published by Elsevier Masson SAS.

  5. Antioxidant activities of some new chromonyl-2,4-thiazolidinediones and chromonyl-2,4-imidazolidinediones having chromone cores.

    Science.gov (United States)

    Berczyński, Paweł; Kładna, Aleksandra; Kruk, Irena; Piechowska, Teresa; Aboul-Enein, Hassan Y; Bozdağ-Dündar, Oya; Ceylan-Unlusoy, Meltem

    2013-11-01

    The antioxidant properties of 11 new synthesized chromonyl-2,4-thiazolidinediones and chromonyl-2,4-imidazolidinediones (CBs) were investigated. The antioxidant activities and mechanisms of the CBs interaction with reactive oxygen species (ROS) were clarified using various in vitro antioxidant assay methods including superoxide anion radical (O2(•-)), hydroxyl radical (HO(•)), 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH(•)) scavenging activity and the iron (II)-ferrozine complex formation. The potassium superoxide/18-crown-6 ether dissolved in dimethylsulfoxide (DMSO) was applied as a source of superoxide anion radical. Hydroxyl radicals were produced in the Fenton-like reaction Fe(II)+H2O2. Chemiluminescence, spectrophotometry, and electron paramagnetic resonance (EPR) spectroscopy using 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) as spin trap were applied as the measurement techniques. The CBs examined that exhibited good free radical scavenging activity also showed strong total antioxidant power capacity. Possible mechanisms of antioxidation are proposed to explain the differences in the experimental results between the chromone derivatives with imidazolidine-2,4-dione ring and those with thiazolidine-2,4-dione ring. In conclusion, some of the new CBs are promising to be applied as inhibitors of free radicals.

  6. Oxalicumone A, a new dihydrothiophene-condensed sulfur chromone induces apoptosis in leukemia cells through endoplasmic reticulum stress pathway.

    Science.gov (United States)

    Wang, Jie; Wang, Qiao-Li; Nong, Xu-Hua; Zhang, Xiao-Yong; Xu, Xin-Ya; Qi, Shu-Hua; Wang, Yi-Fei

    2016-07-15

    Oxalicumone A (POA1), a novel dihydrothiophene-condensed sulfur chromone isolated from the marine fungus Penicillium oxalicum SCSGAF 0023, showed cytotoxicity against several cancer cells previously. In this study, its anti-cancer activity and underlying mechanism of this action were investigated in leukemia cells like KG-1a, HL60, U937, and K562. The results showed that POA1 inhibited dose-/time-dependently cell growth and induced apoptosis in leukemia cells. Also, POA1 caused cleavages of caspase-3, 8, 9 and PARP1, loss of mitochondrial membrane potential, up-regulations of phosphorylated p38 and JNK, and activation of endoplasmic reticulum stress (ER stress). Furthermore, 4-PBA (an ER stress inhibitor) but not SP600125 and SB203580 (JNK and p38 inhibitor, respectively) could largely inhibit POA1-induced growth suppression. Additionally, 4-PBA obstructed mitochondrial depolarization and cleavage of PARP1. These data suggested that ER stress pathway might be an important mediator in POA1-induced apoptosis. In conclusion, POA1 may have antitumor effects in leukemia cells through the induction of ER stress pathway. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Synthesis, structure, infrared and fluorescence spectra of new rare earth complexes with 6-hydroxy chromone-3-carbaldehyde benzoyl hydrazone

    Science.gov (United States)

    Wang, Bao-Dui; Yang, Zheng-Yin; Zhang, Ding-Wa; Wang, Yan

    2006-01-01

    A novel 6-hydroxy chromone-3-carbaldehyde benzoyl hydrazone ligand and its four complexes, [LnL2(NO3)2]NO3 [Ln = Eu(1), Sm(2), Tb(3), Dy(4)], were synthesized. The complexes were characterized by the elemental analyses, molar conductivity and IR spectra. The crystal and molecular structure of Sm(III) complex was determined by single-crystal X-ray diffraction: crystallized in the triclinic system, space group P-1, Z = 1, a = 11.037(4) Å, b = 14.770(5) Å, c = 15.032(7) Å, α = 60.583(4), β = 75.528(7), γ = 88.999(4), R1 = 0.0349. The fluorescence properties of complexes in the solid state and in the organic solvent were studied in detail, respectively. Under the excitation of ultraviolet light, strong red fluorescence of solid europium complex was observed. But the green fluorescence of solid terbium complex was not observed. These observations show that the ligand favor energy transfers to the emitting energy level of Eu3+. Some factors that influence the fluorescent intensity were also discussed.

  8. Synthesis and Characterization of 5-Hydroxy-2-(2-phenylethyl)chromone (5-HPEC) and Its Analogues as Non-nitrogenous 5-HT2B Ligands.

    Science.gov (United States)

    Williams, Dwight A; Zaidi, Saheem A; Zhang, Yan

    2015-08-28

    The involvement of the neurotransmitter serotonin (5-HT) in numerous physiological functions is often attributed to the diversity of receptors with which it interacts. Ligands targeting serotonin receptor 2B (5-HT2B) have received renewed interest for their potential to help understand the role of 5-HT2B in migraines, drug abuse, neurodegenerative diseases, and irritable bowel syndrome. To date, most of the ligands targeting 5-HT2B have been nitrogen-containing compounds. The natural product 5-hydroxy-2-(2-phenylethyl)chromone (5-HPEC, 5) has been shown previously to act as a non-nitrogenous antagonist for the 5-HT2B receptor (pKi = 5.6). This report describes further progress on the study of the structure-activity relationship of both naturally occurring and synthetic compounds bearing the 2-(2-phenylethyl)chromone scaffold at the 5-HT2B receptor. The inhibitory activity of the newly synthesized compounds (at 10 μM) was tested against each of the 5-HT2 receptors. Following this assay, the binding affinity and antagonism of the most promising compounds were then evaluated at 5-HT2B. Among all the analogues, 5-hydroxy-2-(2-phenylpropyl)chromone (5-HPPC, 22h) emerged as a new lead compound, showing a 10-fold improvement in affinity (pKi = 6.6) over 5-HPEC with reasonable antagonist properties at 5-HT2B. Additionally, ligand docking studies have identified a putative binding pocket for 5-HPPC and have helped understand its improved affinity.

  9. Four New 2-(2-Phenylethyl)chromone Derivatives from Chinese Agarwood Produced via the Whole-Tree Agarwood-Inducing Technique.

    Science.gov (United States)

    Liu, Yang-Yang; Chen, De-Li; Wei, Jian-He; Feng, Jian; Zhang, Zheng; Yang, Yun; Zheng, Wei

    2016-10-27

    Four new 2-(2-phenylethyl)chromone derivatives (1-4) were isolated from the EtOH extract of Chinese agarwood produced via the whole-tree agarwood-inducing technique, coming from Aquilaria sinensis (Lour.) Spreng. (Thymelaeaceae). Their structures were elucidated by extensive spectroscopic methods, such as UV, IR, MS, 1D as well as 2D NMR. All of the isolates were then assessed for their anti-inflammatory activities on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW 264.7. Compound 1 exhibited significant inhibitory activity with an IC50 value of 4.6 μM.

  10. NATO Advanced Study Institute on Advances in the Computer Simulations of Liquid Crystals

    CERN Document Server

    Zannoni, Claudio

    2000-01-01

    Computer simulations provide an essential set of tools for understanding the macroscopic properties of liquid crystals and of their phase transitions in terms of molecular models. While simulations of liquid crystals are based on the same general Monte Carlo and molecular dynamics techniques as are used for other fluids, they present a number of specific problems and peculiarities connected to the intrinsic properties of these mesophases. The field of computer simulations of anisotropic fluids is interdisciplinary and is evolving very rapidly. The present volume covers a variety of techniques and model systems, from lattices to hard particle and Gay-Berne to atomistic, for thermotropics, lyotropics, and some biologically interesting liquid crystals. Contributions are written by an excellent panel of international lecturers and provides a timely account of the techniques and problems in the field.

  11. Self-assembled ordered structures in thin films of HAT5 discotic liquid crystal

    Directory of Open Access Journals (Sweden)

    Piero Morales

    2010-05-01

    Full Text Available Thin films of the discotic liquid crystal hexapentyloxytriphenylene (HAT5, prepared from solution via casting or spin-coating, were investigated by atomic force microscopy and polarizing optical microscopy, revealing large-scale ordered structures substantially different from those typically observed in standard samples of the same material. Thin and very long fibrils of planar-aligned liquid crystal were found, possibly formed as a result of an intermediate lyotropic nematic state arising during the solvent evaporation process. Moreover, in sufficiently thin films the crystallization seems to be suppressed, extending the uniform order of the liquid crystal phase down to room temperature. This should be compared to the bulk situation, where the same material crystallizes into a polymorphic structure at 68 °C.

  12. Structure-spectroscopic relationship of co-crystals between a rare chromone structure type of barakol and some organic acids

    Science.gov (United States)

    Chimsook, T.; Teerawatananond, T.; Ngamrojnavanich, N.; Chaichit, N.; Kongsaeree, P.; Muangsin, N.

    2013-12-01

    Barakol, extracted from Cassia siamea Lamk. having an anxiolytic property, consists of a rare chromone core structure, therefore, in this work we investigate relation between the X-ray crystallography and physical properties such as spectroscopic data and the intermolecular interactions of the keto-enol forms based on the CSD search, especially e.g. hydrogen bonding, π-π interactions, ionic interactions and acid-base interactions and clarifies their ambiguous spectroscopic properties. The 1:1 molecular complexes of barakol and carboxylic acid (phthalic acid and 3-hydroxybenzoic acid) were prepared and the X-ray crystallographic studies revealed that the barakol-phthalate complex exists in an ion-pair complex. The formation of barakol-phthalate ion-pair complex is stabilized by the complementary of ion-ion interactions, π-π interactions and hydrogen bonding. The barakol-3-hydroxybenzoic acid complex is a π-π molecular complex. The co-crystallization of barakol-3-hydroxybenzoic acid complex is solely stabilized by π-π interactions. The spectroscopic studies including IR, 1H NMR and 13C NMR are consistent with the results from the X-ray analysis. The 1H NMR spectrum of the barakol and phthalic acid complex in a mixture of CDCl3-CD3OD showed a dramatic spectral changes with downfield shifts of the ortho-protons of phthalic acid (ΔδH(ppm) = 0.37), and the proton resonances of barakol (ΔδH(ppm) = 0.31 for proton H3, 0.53 for proton H4, 0.57 for proton H6 and 0.33 for proton H9).

  13. Catalytic synthesis of α-amino chromone phosphonates and their antimicrobial, toxicity and potential HIV-1 RT inhibitors based on silico screening.

    Science.gov (United States)

    Jaiyeola, Abosede Oluwabukola; Anand, K; Kasumbwe, K; Ramesh, M; Gengan, R M

    2017-01-01

    The α-amino phosphonates exhibit a wide range of biological properties which create demand for simple and efficient synthetic routes of new molecules. In this study synthesis of a new series of derivatives of α-amino chromone phosphonates (ACPs) was reported using RhBT catalyst. The RhBT was first prepared by simply mixing boron nitride in a solution of rhodium acetate, under inert atmosphere for a week followed by filtration (yield: 92%). The catalyst can be re-used for up to four times and showed minimal loss of activity. The ACPs was prepared in a one pot reaction containing chromone based aldehydes, aniline derivatives and diethyl phosphite. The structures of these compounds were characterized by IR, (1)H NMR, (13)C NMR, (31)P NMR and high resolution mass spectral analysis. The synthesized ACPs were evaluated for their antimicrobial activities against three bacteria B. cereus, M. luteus, E. coli and one fungus C. albicans. The ACPs displayed selective toxicity toward the brine shrimp (Artemia salina). Compounds 8j and 8m was found to be less toxic to the brine shrimp and may have more valuable biological application. Furthermore, molecular docking studies were conducted to predict the possible therapeutic potential of ACPs. The compounds (8i, 8j, 8k and 8m) were predicted as highly active HIV-1 reverse transcriptase inhibitors. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Synthesis and anticancer activity of novel 4-morpholino-7,8-dihydro-5H-thiopyrano[4,3-d]pyrimidine derivatives bearing chromone moiety.

    Science.gov (United States)

    Sun, Chengyu; Chen, Chen; Xu, Shan; Wang, Jianqiang; Zhu, Yan; Kong, Dejia; Tao, Hong; Jin, Mengjia; Zheng, Pengwu; Zhu, Wufu

    2016-08-15

    Herein, we designed and synthesized of a novel series of 7,8-dihydro-5H-thiopyrano[4,3-d]pyrimidine derivatives bearing chromone moiety (10a-j, 13a-j). All the compounds were evaluated for the IC50 values against five cancer cell lines (A549, PC-3, MCF-7, Hela and HepG2). Seven of the target compounds exhibited moderate to excellent cytotoxicity. For these compounds, we tested their inhibitory activities against mTOR kinase, and four of them were tested their inhibitory activities against PI3Kα kinase in further. The results indicated that the optimized compound 10j showed excellent inhibitory activity and cytotoxicity against mTOR kinase, PI3Kα kinase and five cancer cell lines with IC50 values of 1.1μM, 0.92μM and 8.77-14.3μM. Structure-activity relationships (SARs) and docking studies indicated that the thiopyrano[4,3-d]pyrimidine scaffolds exerted little effect on antitumor activities of target compounds. Substitutions of chromone moiety at C-6 position with carboxyl were benefit to the antitumor activities. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. In vivo safety evaluation of UP780, a standardized composition of aloe chromone aloesin formulated with an Aloe vera inner leaf fillet.

    Science.gov (United States)

    Yimam, Mesfin; Brownell, Lidia; Jia, Qi

    2014-08-01

    Safety profiles of the aloe chromone aloesin or Aloe vera inner leaf fillet (Qmatrix) as a well tolerated entity have been reported separately. UP780, a standardized composition of aloe chromone formulated with an Aloe vera inner leaf fillet, has shown a significant beneficial effect in lowering blood glucose and improving insulin resistance in human. Here we evaluate the safety of UP780 after a repeated 14 and 90-day oral administration in CD-1 mice. UP780 was given at doses of 100mg/kg/day, 500mg/kg/day and 1000mg/kg/day to groups of 10 male and 10 female for 90days or administered by oral gavage at a dose of 2g/kg/day to groups of 5 male and 5 female for 14days. Body weight, feed consumption, hematology, clinical chemistry and histopathologic evaluation were performed. UP780 at a dose of 1000mg/kg/day or at 2000mg/kg/day produced no treatment-related toxicity or mortality. Body weight gain or feed consumption was similar between groups. There was no test article-related microscopic change. Spontaneously occurring minor changes in clinical chemistry and hematology were observed. However, these changes were limited to one sex or were not dose correlated. UP780 was well tolerated in this strain. A dose of 2000mg/kg/day was identified as the NOAEL (no-observed-adverse-effect-level).

  16. A comparison of the structures of some 2- and 3-substituted chromone derivatives: a structural study on the importance of the secondary carboxamide backbone for the inhibitory activity of MAO-B

    Science.gov (United States)

    Gomes, Ligia R.; Low, John Nicolson; Cagide, Fernando; Gaspar, Alexandra; Borges, Fernanda

    2015-01-01

    The crystal structures of the 3-substituted tertiary chromone carboxamide derivative, C17H13NO3, N-methyl-4-oxo-N-phenyl-4H-chromene-3-carboxamide (1), and the chromone carbonyl pyrrolidine derivatives, C14H13NO3, 3-(pyrrolidine-1-carbon­yl)-4H-chromen-4-one (3) and 2-(pyrrolidine-1-carbon­yl)-4H-chromen-4-one (4) have been determined. Their structural features are discussed and compared with similar compounds namely with respect to their MAO-B inhibitory activities. The chromone carboxamide presents a –syn conformation with the aromatic rings twisted with respect to each other [the dihedral angle between the mean planes of the chromone system and the exocyclic phenyl ring is 58.48 (8)°]. The pyrrolidine derivatives also display a significant twist: the dihedral angles between the chromone system and the best plane formed by the pyrrolidine atoms are 48.9 (2) and 23.97 (12)° in (3) and (4), respectively. Compound (3) shows a short C—H⋯O intra­molecular contact forming an S(7) ring. The supra­molecular structures for each compound are defined by weak C—H⋯O hydrogen bonds, which link the mol­ecules into chains and sheets. The Cambridge Structural Database gave 45 hits for compounds with a pyrrolidinecarbonyl group. A simple statistical analysis of their geometric parameters is made in order to compare them with those of the mol­ecules determined in the present work. PMID:26594490

  17. One- and two-dimensional fluids properties of smectic, lamellar and columnar liquid crystals

    CERN Document Server

    Jakli, Antal

    2006-01-01

    Smectic and lamellar liquid crystals are three-dimensional layered structures in which each layer behaves as a two-dimensional fluid. Because of their reduced dimensionality they have unique physical properties and challenging theoretical descriptions, and are the subject of much current research. One- and Two-Dimensional Fluids: Properties of Smectic, Lamellar and Columnar Liquid Crystals offers a comprehensive review of these phases and their applications. The book details the basic structures and properties of one- and two-dimensional fluids and the nature of phase transitions. The later chapters consider the optical, magnetic, and electrical properties of special structures, including uniformly and non-uniformly aligned anisotropic films, lyotropic lamellar systems, helical and chiral structures, and organic anisotropic materials. Topics also include typical and defective features, magnetic susceptibility, and electrical conductivity. The book concludes with a review of current and potential applications ...

  18. Liquids and liquid mixtures

    CERN Document Server

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

    2013-01-01

    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

  19. Effect of ionic liquids on the different hierarchical order of type I collagen.

    Science.gov (United States)

    Mehta, Ami; Rao, J Raghava; Fathima, Nishter Nishad

    2014-05-01

    The effect of ionic liquids (ILs) on proteins has been gaining huge interest due to easy tunability of cation and anion for generating the desired effect. This study explores the effect of alkyl imidazolium chloride ILs on collagen at molecular, inter-fibrillar and skin matrix level. Circular dichroic studies reveal that at the molecular level, the secondary structure of collagen was not affected by imidazolium ILs and there was no change in thermal stability as well. However, collagen at the inter-fibrillar level behaved differently. With increase in concentration of ILs, remarkable decrease in thermal stability of rat tail tendon (RTT) collagen fibers with marginal swelling effect was seen. SEM micrographs of skin matrix treated with IL show opening up of pores. This kind of exquisite behavior of ILs at different hierarchal order of collagen indicates that ILs are endowed with potential lyotropic action, which can be judiciously employed for biomedical applications.

  20. Discovery of New Chemical Entities for Old Targets: Insights on the Lead Optimization of Chromone-Based Monoamine Oxidase B (MAO-B) Inhibitors.

    Science.gov (United States)

    Reis, Joana; Cagide, Fernando; Chavarria, Daniel; Silva, Tiago; Fernandes, Carlos; Gaspar, Alexandra; Uriarte, Eugenio; Remião, Fernando; Alcaro, Stefano; Ortuso, Francesco; Borges, Fernanda

    2016-06-23

    The discovery of new chemical entities endowed with potent, selective, and reversible monoamine oxidase B inhibitory activity is a clinically relevant subject. Therefore, a small library of chromone derivatives was synthesized and screened toward human monoamine oxidase isoforms (hMAO-A and hMAO-B). The structure-activity relationships studies strengthen the importance of the amide spacer and the direct linkage of carbonyl group to the γ-pyrone ring, along with the presence of meta and para substituents in the exocyclic ring. The most potent MAO-B inhibitors were N-(3'-chlorophenyl)-4-oxo-4H-chromene-3-carboxamide (20) (IC50 = 403 pM) and N-(3',4'-dimethylphenyl)-4-oxo-4H-chromene-3-carboxamide (27) (IC50 = 669 pM), acting as competitive and noncompetitive reversible inhibitors, respectively. Computational docking studies provided insights into enzyme-inhibitor interactions and a rationale for the observed selectivity and potency. Compound 27 stands out due to its favorable toxicological profile and physicochemical properties, which pointed toward blood-brain barrier permeability, thus being a valid candidate for subsequent animal studies.

  1. Spectra and DNA-binding affinities of Copper(II), Nickel(II) complexes with a novel glycine Schiff base derived from chromone

    Science.gov (United States)

    Qin, Dong-dong; Yang, Zheng-yin; Wang, Bao-dui

    2007-11-01

    New [CuL·(H 2O) 3]NO 3·H 2O and [NiL·H 2O]NO 3·2H 2O complexes with Schiff base (LNa) derived from 6-hydroxy-3-carbaldehyde chromone (CDC) and glycine are reported. Two complexes have been characterized by elemental analysis, IR data, TG/DTA and molar conductivity. The binding of these two complexes to calf thymus DNA (CT-DNA) has been investigated, respectively, with UV-vis spectroscopy, fluorescence spectroscopy and viscosity measurements. The experiment results indicate that the two complexes may bind to CT-DNA through an intercalative mode and [CuL·(H 2O) 3]NO 3·H 2O intercalates into DNA more deeply than [NiL·H 2O]NO 3·2H 2O. Their intrinsic binding constants ( K) with DNA are 6.08 × 10 5 and 2.76 × 10 5 M -1.

  2. 5,6,7,8-Tetrahydro-2-(2-phenylethyl)chromones from artificial agarwood of Aquilaria sinensis and their inhibitory activity against acetylcholinesterase.

    Science.gov (United States)

    Liao, Ge; Mei, Wen-Li; Kong, Fan-Dong; Li, Wei; Yuan, Jing-Zhe; Dai, Hao-Fu

    2017-07-01

    Thirteen previously undescribed 5,6,7,8-tetrahydro-2-(2-phenylethyl)chromones named tetrahydrochromone A-M, together with nine known ones, were isolated from artificial agarwood (induced by holing) originating from Aquilaria sinensis (Lour.) Gilg. The structures of these compounds were unambiguously determined based on extensive NMR spectroscopic analyses, and the absolute configuration was resolved by CD analyses, X-ray crystallographic, chemical and Mosher's method. Tetrahydrochromone A, B, K-M, and Oxidoagarochromone An exhibited inhibitory activity against AChE with the percentage inhibition range from 17.5% to 47.9% (with Tacrine as the positive control; inhibition ratio: 66.7%) when tested at 50 μg/mL. Tetrahydrochromone A-E, F-J feature one methoxy and three hydroxys linked at the cyclohexene ring rather than usual four hydroxys, and tetrahydrochromone K-M represent the first examples of 7,8-epoxy tetrahydrochromones. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. A novel chromone derivative with anti-inflammatory property via inhibition of ROS-dependent activation of TRAF6-ASK1-p38 pathway.

    Directory of Open Access Journals (Sweden)

    Hailiang Liu

    Full Text Available The p38 MAPK signaling pathway plays a pivotal role in inflammation. Targeting p38 MAPK may be a potential strategy for the treatment of inflammatory diseases. In the present study, we show that a novel chromone derivative, DCO-6, significantly reduced lipopolysaccharide (LPS-induced production of nitric oxide, IL-1β and IL-6, decreased the levels of iNOS, IL-1β and IL-6 mRNA expression in both RAW264.7 cells and mouse primary peritoneal macrophages, and inhibited LPS-induced activation of p38 MAPK but not of JNK, ERK. Moreover, DCO-6 specifically inhibited TLR4-dependent p38 activation without directly inhibiting its kinase activity. LPS-induced production of intracellular reactive oxygen species (ROS was remarkably impaired by DCO-6, which disrupted the formation of the TRAF6-ASK1 complex. Administering DCO-6 significantly protected mice from LPS-induced septic shock in parallel with the inhibition of p38 activation and ROS production. Our results indicate that DCO-6 showed anti-inflammatory properties through inhibition of ROS-dependent activation of TRAF6-ASK1-p38 pathway. Blockade of the upstream events required for p38 MAPK action by DCO-6 may provide a new therapeutic option in the treatment of inflammatory diseases.

  4. A Novel Chromone Derivative with Anti-Inflammatory Property via Inhibition of ROS-Dependent Activation of TRAF6-ASK1-p38 Pathway

    Science.gov (United States)

    Liu, Hailiang; Xu, Rui; Feng, Lili; Guo, Wenjie; Cao, Ning; Qian, Cheng; Teng, Peng; Wang, Lu; Wu, Xuefeng; Sun, Yang; Li, Jianxin; Shen, Yan; Xu, Qiang

    2012-01-01

    The p38 MAPK signaling pathway plays a pivotal role in inflammation. Targeting p38 MAPK may be a potential strategy for the treatment of inflammatory diseases. In the present study, we show that a novel chromone derivative, DCO-6, significantly reduced lipopolysaccharide (LPS)-induced production of nitric oxide, IL-1β and IL-6, decreased the levels of iNOS, IL-1β and IL-6 mRNA expression in both RAW264.7 cells and mouse primary peritoneal macrophages, and inhibited LPS-induced activation of p38 MAPK but not of JNK, ERK. Moreover, DCO-6 specifically inhibited TLR4-dependent p38 activation without directly inhibiting its kinase activity. LPS-induced production of intracellular reactive oxygen species (ROS) was remarkably impaired by DCO-6, which disrupted the formation of the TRAF6-ASK1 complex. Administering DCO-6 significantly protected mice from LPS-induced septic shock in parallel with the inhibition of p38 activation and ROS production. Our results indicate that DCO-6 showed anti-inflammatory properties through inhibition of ROS-dependent activation of TRAF6-ASK1-p38 pathway. Blockade of the upstream events required for p38 MAPK action by DCO-6 may provide a new therapeutic option in the treatment of inflammatory diseases. PMID:22720096

  5. Ambient ionization mass spectrometry imaging of rohitukine, a chromone anti-cancer alkaloid, during seed development in Dysoxylum binectariferum Hook.f (Meliaceae).

    Science.gov (United States)

    Mohana Kumara, P; Srimany, Amitava; Ravikanth, G; Uma Shaanker, R; Pradeep, T

    2015-08-01

    Rohitukine, a chromone alkaloid, possesses anti-inflammatory, anti-cancer and immuno-modulatory properties. It has been reported from four species, belonging to the families, Meliaceae and Rubiaceae. Stem bark of Dysoxylum binectariferum (Meliaceae) accumulates the highest amount of rohitukine (3-7% by dry weight). In this study, we examine the spatial and temporal distribution of rohitukine and related compounds during various stages of seed development in D. binectariferum using desorption electrospray ionization mass spectrometry imaging (DESI MSI). Rohitukine (m/z 306.2) accumulation increased from early seed development to seed maturity stage. The spatial distribution of rohitukine was largely restricted to the cotyledonary tissue followed by the embryo and least in the seed coat. Besides rohitukine, rohitukine acetate (m/z 348.2) and glycosylated rohitukine (m/z 468.2) were also detected, both through mass fragmentation and exact mass analysis through Orbitrap mass spectrometry. These results indicate a dynamic pattern of chromane alkaloid accumulation through seed development in D. binectariferum. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Bicelle-based liquid crystals for NMR-measurement of dipolar couplings at acidic and basic pH values

    Energy Technology Data Exchange (ETDEWEB)

    Ottiger, Marcel; Bax, Ad [National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Laboratory of Chemical Physics (United States)

    1999-02-15

    It is demonstrated that mixtures of ditetradecyl- phosphatidylcholine or didodecyl-phoshatidylcholine and dihexyl- phosphatidylcholine in water form lyotropic liquid crystalline phases under similar conditions as previously reported for bicelles consisting of dimyristoyl-phosphatidylcholine (DMPC) and dihexanoyl- phosphatidylcholine (DHPC). The carboxy-ester bonds present in DMPC and DHPC are replaced by ether linkages in their alkyl analogs, which prevents acid- or base-catalyzed hydrolysis of these compounds. 15N-1H dipolar couplings measured for ubiquitin over the 2.3-10.4pH range indicate that this protein retains a backbone conformation which is very similar to its structure at pH 6.5 over this entire range.

  7. The Effect of Electroporation of a Lyotroic Liquid Crystal Genistein-Based Formulation in the Recovery of Murine Melanoma Lesions.

    Science.gov (United States)

    Danciu, Corina; Berkó, Szilvia; Varju, Gábor; Balázs, Boglárka; Kemény, Lajos; Németh, István Balázs; Cioca, Andreea; Petruș, Alexandra; Dehelean, Cristina; Cosmin, Citu Ioan; Amaricai, Elena; Toma, Claudia Crina

    2015-07-08

    A lamellar lyotropic liquid crystal genistein-based formulation (LLC-Gen) was prepared in order to increase the aqueous solubility of the lipophilic phytocompound genistein. The formulation was applied locally, in a murine model of melanoma, with or without electroporation. The results demonstrated that, when the formulation was applied by electroporation, the tumors appeared later. During the 21 days of the experiment, the LLC-Gen formulation decreased the tumor volume, the amount of melanin and the degree of erythema, but when electroporation was applied, all these parameters indicated a better prognosis even (lower tumor volume, amount of melanin and degree of erythema). Although hematoxylin-eosin (HE) staining confirmed the above events, application of the LLC-Gen formulation by electroporation did not lead to a significant effect in terms of the serum concentrations of the protein S100B and serum neuron specific enolase (NSE), or the tissue expression of the platelet-derived growth factor receptor β (PDGFRβ) antibody.

  8. Synthesis, Molecular Docking, Molecular Dynamics Studies, and Biological Evaluation of 4H-Chromone-1,2,3,4-tetrahydropyrimidine-5-carboxylate Derivatives as Potential Antileukemic Agents.

    Science.gov (United States)

    Dolatkhah, Zahra; Javanshir, Shahrzad; Sadr, Ahmad Shahir; Hosseini, Jaber; Sardari, Soroush

    2017-06-26

    A series of 4H-chromone-1,2,3,4-tetrahydropyrimidine-5-carboxylates derivatives were synthesized via a three component one-pot condensation of chromone-3-carbaldehyde, alkyl acetoacetate, and urea or thiourea, using MCM-41-SO3H as efficient nanocatalysts and evaluated for their anticancer activity using a combined in silico docking and molecular dynamics protocol to estimate the binding affinity of the title compounds with the Bcr-Abl oncogene. Two programs, AutoDock 4 and AutoDock Vina software were applied to dock the target protein with synthesized compounds and ATP. AutoDock runs resulted in binding energy scores from -7.8 to -10.16 kcal/mol for AutoDock 4 and -6.9 to -8.5 (kcal/mol) for AutoDock Vina. Furthermore, molecular dynamics (MD) simulations are performed using Gromacs for up to 20 ns simulation time investigating the stability of a ligand-protein complex. Finally, a theoretical experiment using MD simulation for 10 ns was performed without defining the initial coordinates, and the affinity binding of ligand to receptors was directly studied, which revealed that the ligand approaches the active sites. The relative free binding energy for the structure 06 (S06), which has the highest binding energy in Autodock 4 and Autodock Vina (-10.10 and -8.5 kcal/mol, respectively), was also evaluated by molecular mechanics (MM) with Poisson-Boltzmann (PB) and a surface area solvation (MM-PBSA) method using g_mmpbsa tools for the last 15 ns MD. On the basis of binding energy scores, a negative binding energy value of 73.6 kcal/mol, S06, was recognized as the dominant potential inhibitors. The cytotoxic properties of S06 was evaluated against three cell lines, acute T cell leukemia (Jurkat), human chronic myelogenous leukemia, (K562) and human foreskin fibroblast (Hu02) using the microculture tetrazolium test MTT assay. Cisplatin was used as the reference agent. The results indicated that S06 has a higher safety index (SI = 0.73, IC50 = 152.64 μg/mL for Jurkat and

  9. Chromone linked nitrone derivative induces the expression of iNOS2 and Th1 cytokines but reduces the Th2 response in experimental visceral leishmaniasis.

    Science.gov (United States)

    Mallick, Suvadip; Halder, Subhadra; Dutta, Aritri; Dey, Somaditya; Paul, Kausik; Maiti, Sourav; Bandyopadhyay, Chandrakanta; Saha, Bhaskar; Pal, Chiranjib

    2013-04-01

    In our previous work we have shown that the novel synthetic chromone derivative could effectively inhibit the Leishmania donovani replication in vitro and in vivo with less cytotoxicity on murine splenocytes. The aim of the present study is to explore the possible mechanism of anti-leishmanial effect of C-(6-methyl-4-oxo-4H-1-benzopyran-3-yl)-N-(p-tolyl) nitrone (designated as NP1) in vitro and in vivo in experimental visceral leishmaniasis caused by L. donovani. The cytotoxic effect of this derivative was studied in murine peritoneal macrophages by MTT method. NP1 at a dose of 17.06 μM showed 50% inhibition on L. donovani promastigotes but found less cytotoxic to the RAW 264.7 cells. Even the higher concentration of IC50 (up to four fold) did not exert much cytotoxic effect on RAW 264.7. Interestingly, NP1 at lower concentration (8.53 μM) could inhibit 50% of intracellular amastigotes in murine peritoneal macrophages. L. donovani is known to exert its pathogenic effects mainly by the suppression of NO generation and subversion of the cellular inflammatory responses in the macrophages. NP1 was found to induce a potent host-protective immune response by enhancing NO generation and iNOS2 expression at mRNA level and by up-regulating proinflammatory cytokines such as IL-12 and IFN-γ and limiting the expression of IL-10 in vivo. The NO dependent killing was further confirmed in iNOS(-/-) mice compared to wild type. In agreement with the fact, induced synthesis of IL-12 and IFN-γ and associated down-regulation of IL-10 by the treatment of NP1 clearly indicated the possibility of novel strategy of drug development against Leishmania infection. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. The Effect of Liquid Crystalline Structures on Antiseizure Properties of Aqueous Solutions of Ethoxylated Alcohols

    Directory of Open Access Journals (Sweden)

    Anna Bak

    2010-01-01

    Full Text Available 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.

  11. The effect of liquid crystalline structures on antiseizure properties of aqueous solutions of ethoxylated alcohols.

    Science.gov (United States)

    Sulek, Marian Wlodzimierz; Bak, Anna

    2010-01-12

    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.

  12. Straining soft colloids in aqueous nematic liquid crystals

    Science.gov (United States)

    Mushenheim, Peter C.; Pendery, Joel S.; Weibel, Douglas B.; Spagnolie, Saverio E.; Abbott, Nicholas L.

    2016-05-01

    Liquid crystals (LCs), because of their long-range molecular ordering, are anisotropic, elastic fluids. Herein, we report that elastic stresses imparted by nematic LCs can dynamically shape soft colloids and tune their physical properties. Specifically, we use giant unilamellar vesicles (GUVs) as soft colloids and explore the interplay of mechanical strain when the GUVs are confined within aqueous chromonic LC phases. Accompanying thermal quenching from isotropic to LC phases, we observe the elasticity of the LC phases to transform initially spherical GUVs (diameters of 2-50 µm) into two distinct populations of GUVs with spindle-like shapes and aspect ratios as large as 10. Large GUVs are strained to a small extent (R/r minor radii, respectively), consistent with an LC elasticity-induced expansion of lipid membrane surface area of up to 3% and conservation of the internal GUV volume. Small GUVs, in contrast, form highly elongated spindles (1.54 materials and suggest previously unidentified designs of LC-based responsive and reconfigurable materials.

  13. The Chromone Alkaloid, Rohitukine, Affords Anti-Cancer Activity via Modulating Apoptosis Pathways in A549 Cell Line and Yeast Mitogen Activated Protein Kinase (MAPK Pathway.

    Directory of Open Access Journals (Sweden)

    Safia

    Full Text Available The field of cancer research and treatment has made significant progress, yet we are far from having completely safe, efficient and specific therapies that target cancer cells and spare the healthy tissues. Natural compounds may reduce the problems related to cancer treatment. Currently, many plant products are being used to treat cancer. In this study, Rohitukine, a natural occurring chromone alkaloid extracted from Dysoxylum binectariferum, was investigated for cytotoxic properties against budding yeast as well as against lung cancer (A549 cells. We endeavored to specifically study Rohitukine in S. cerevisiae in the context of MAPK pathways as yeast probably represents the experimental model where the organization and regulation of MAPK pathways are best understood. MAPK are evolutionarily conserved protein kinases that transfer extracellular signals to the machinery controlling essential cellular processes like growth, migration, differentiation, cell division and apoptosis. We aimed at carrying out hypothesis driven studies towards targeting the important network of cellular communication, a critical process that gets awry in cancer. Employing mutant strains of genetic model system Saccharomyces cerevisiae. S. cerevisiae encodes five MAPKs involved in control of distinct cellular responses such as growth, differentiation, migration and apoptosis. Our study involves gene knockouts of Slt2 and Hog1 which are functional homologs of human ERK5 and mammalian p38 MAPK, respectively. We performed cytotoxicity assay to evaluate the effect of Rohitukine on cell viability and also determined the effects of drug on generation of reactive oxygen species, induction of apoptosis and expression of Slt2 and Hog1 gene at mRNA level in the presence of drug. The results of this study show a differential effect in the activity of drug between the WT, Slt2 and Hog1 gene deletion strain indicating involvement of MAPK pathway. Further, we investigated Rohitukine

  14. The Chromone Alkaloid, Rohitukine, Affords Anti-Cancer Activity via Modulating Apoptosis Pathways in A549 Cell Line and Yeast Mitogen Activated Protein Kinase (MAPK) Pathway.

    Science.gov (United States)

    Safia; Kamil, Mohd; Jadiya, Pooja; Sheikh, Saba; Haque, Ejazul; Nazir, Aamir; Lakshmi, Vijai; Mir, Snober S

    2015-01-01

    The field of cancer research and treatment has made significant progress, yet we are far from having completely safe, efficient and specific therapies that target cancer cells and spare the healthy tissues. Natural compounds may reduce the problems related to cancer treatment. Currently, many plant products are being used to treat cancer. In this study, Rohitukine, a natural occurring chromone alkaloid extracted from Dysoxylum binectariferum, was investigated for cytotoxic properties against budding yeast as well as against lung cancer (A549) cells. We endeavored to specifically study Rohitukine in S. cerevisiae in the context of MAPK pathways as yeast probably represents the experimental model where the organization and regulation of MAPK pathways are best understood. MAPK are evolutionarily conserved protein kinases that transfer extracellular signals to the machinery controlling essential cellular processes like growth, migration, differentiation, cell division and apoptosis. We aimed at carrying out hypothesis driven studies towards targeting the important network of cellular communication, a critical process that gets awry in cancer. Employing mutant strains of genetic model system Saccharomyces cerevisiae. S. cerevisiae encodes five MAPKs involved in control of distinct cellular responses such as growth, differentiation, migration and apoptosis. Our study involves gene knockouts of Slt2 and Hog1 which are functional homologs of human ERK5 and mammalian p38 MAPK, respectively. We performed cytotoxicity assay to evaluate the effect of Rohitukine on cell viability and also determined the effects of drug on generation of reactive oxygen species, induction of apoptosis and expression of Slt2 and Hog1 gene at mRNA level in the presence of drug. The results of this study show a differential effect in the activity of drug between the WT, Slt2 and Hog1 gene deletion strain indicating involvement of MAPK pathway. Further, we investigated Rohitukine induced cytotoxic

  15. Double-tandem [4π+2π]•[2π+2π]•[4π+2π]•[2π+2π] Synthetic Sequence with Photoprotolytic Oxametathesis and Photoepoxidation in the Chromone Series

    Science.gov (United States)

    Valiulin, Roman A.; Arisco, Teresa M.; Kutateladze, Andrei G.

    2011-01-01

    Chromones are introduced into a double-tandem [4π+2π]•[2π+2π]•[4π+2π]•[2π+2π] synthetic sequence, culminating in photoprotolytic oxametathesis, which leads to an expeditious growth of molecular complexity over a few experimentally simple steps. The overall reaction can potentially be utilized in diversity-oriented synthesis (DOS) as it allows for three or more diversity inputs furnishing novel unique polycyclic scaffolds decorated with a variety of functionalities and aromatic/heterocyclic pendants. The polycyclic alkenes, resulting from the oxametathesis step, were found to undergo efficient and clean photoinduced epoxidation when irradiated in the presence of molecular oxygen. PMID:21268619

  16. Synthesis and antimicrobial activity of chromone-linked 2-pyridone fused with 1,2,4-triazoles, 1,2,4-triazines and 1,2,4-triazepines ring systems

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Tarik El-Sayed; Ibrahim, Magdy Ahmed, E-mail: magdy_ahmed1977@yahoo.co [Ain Shams University, Cairo (Egypt). Faculty of Education. Dept. of Chemistry

    2010-07-01

    Three series of novel fused nitrogen heterocyclic systems such as 1,2,4-triazolo[1,5-a ] pyridines (5-7 and 9), pyrido[1,2-b][1,2,4]triazines (10, 11, 13 and 15), and pyrido[1,2-b][1,2,4]triazepines (17, 18, 20 and 22) linked with a chromone moiety were synthesized from the key intermediate 1,6-diamino-(6-chloro-4-oxo-4H-chromen-3-yl)-2-oxo-1,2-dihydropyridine-3,5- dicarbonitrile (4) with some electrophilic reagents. The structures of the novel compounds were established by elemental analyses and spectral data. All the products were also screened in vitro for their antimicrobial activity. Compounds 7, 9 and 15 showed the highest activities when compared with the reference drugs. (author)

  17. Market Liquidity and Funding Liquidity

    OpenAIRE

    Brunnermeier, Markus K; Lasse Heje Pedersen

    2007-01-01

    We provide a model that links an asset's market liquidity - i.e., the ease with which it is traded - and traders' funding liquidity - i.e., the ease with which they can obtain funding. Traders provide market liquidity, and their ability to do so depends on their availability of funding. Conversely, traders' funding, i.e., their capital and the margins they are charged, depend on the assets' market liquidity. We show that, under certain conditions, margins are destabilizing and market liquidit...

  18. Market Liquidity and Funding Liquidity

    OpenAIRE

    Markus K. Brunnermeier; Lasse Heje Pedersen

    2007-01-01

    We provide a model that links an asset's market liquidity - i.e., the ease with which it is traded - and traders' funding liquidity - i.e., the ease with which they can obtain funding. Traders provide market liquidity, and their ability to do so depends on their availability of funding. Conversely, traders' funding, i.e., their capital and the margins they are charged, depend on the assets' market liquidity. We show that, under certain conditions, margins are destabilizing and market liquidit...

  19. One-step separation and purification of two chromones and one pyrone from Aloe barbadensis Miller: a comparison between reversed-phase flash chromatography and high-speed counter current chromatography.

    Science.gov (United States)

    Zhong, Jia-Sheng; Wan, Jin-Zhi; Ding, Wen-Jing; Wu, Xiao-Fang; Xie, Zhi-Yong

    2014-01-01

    Chromones and pyrones are the major secondary metabolites of Aloe barbadensis Miller. As they are minor components of the plant, an efficient purification procedure for them is of great importance for promoting their pharmacological studies. To develop efficient methods for one-step separation and purification of two chromones (5-((S)-2'-oxo-4'-hydroxypentyl)-2-hydroxymethylchromone (1) and 5-((4E)-2'-oxo-pentenyl)-2-hydroxymethylchromone (3)) and one pyrone (aloenin aglycone (2)) from A. barbadensis via reversed-phase flash chromatography (RP-FC) and high-speed counter current chromatography (HSCCC). The RP-FC separation was performed using methanol:water (26:74, v/v) as the mobile phase at a flow rate of 20 mL/min. A solvent system composed of dichloromethane:methanol:water (3:1.5:1, v/v/v) was used for the HSCCC separation, at a flow rate of 2.0 mL/min. A one-step RP-FC operation within 110 min was successfully used for the purification of compounds 1 (27.9 mg, 96.5%), 2 (32.4 mg, 98.2%) and 3 (4.1 mg, 99.0%) from 129 mg of crude sample, and a one-step HSCCC separation within 95 min was successfully implemented for the purification of compounds 1 (31.1 mg, 97.6%), 2 (35.8 mg, 96.7%) and 3 (2.7 mg, 98.1%) from 134 mg of crude sample. The developed procedures were efficient, with low cost and high yield, which would afford sufficient amounts of high-purity compounds for chromatographic purposes and pharmacological activity screening. Copyright © 2014 John Wiley & Sons, Ltd.

  20. Anti-AIDS agents. 60. Substituted 3'R,4'R-di-O-(-)-camphanoyl-2',2'-dimethyldihydropyrano[2,3-f]chromone (DCP) analogues as potent anti-HIV agents.

    Science.gov (United States)

    Yu, Donglei; Chen, Chin-Ho; Brossi, Arnold; Lee, Kuo-Hsiung

    2004-07-29

    Synthesis of positional isomers is a commonly used technique in drug design. Accordingly, based on prior SAR studies of 3'R,4'R-di-O-(S)-camphanoyl-(+)-cis-khellactone (DCK, 1) analogues, a series of mono- and disubstituted chromone derivatives of 3'R,4'R-di-O-(-)-camphanoyl-2',2'-dimethyldihydropyrano[2,3-f]chromone (DCP, 4) were designed and synthesized. Together with 1 and 4-methyl DCK (2), all newly synthesized DCP analogues (4-21) were screened for anti-HIV-1 activity against a non-drug-resistant strain in H9 lymphocytes and a multiple reverse transcriptase (RT) inhibitor-resistant strain in the MT4 cell line. Several DCP analogues (4, 5, 7, 8, 13, and 17) exhibited extremely high anti-HIV activity in the non-drug-resistant strain assay, with EC(50) values ranging from 0.00032 to 0.0057 microM and remarkable therapeutic indexes (TI) ranging from 5.6 x 10(3) to 1.16 x 10(5), which were similar to those of 2 (EC(50) 0.0059 microM, TI > 6.6 x 10(3)) and better than those of 1 (EC(50) 0.049 microM, TI > 328). Even more promisingly, some DCP analogues also showed activity against a multi-RT inhibitor-resistant strain, HIV-1 RTMDR1, whereas most DCK analogues did not. The most significant compound was 8, with an EC(50) value of 0.06 microM and TI of 718 against the multi-RT inhibitor-resistant HIV-1 strain. Compounds 9 and 10 also showed good activity with an EC(50) value of 0.14 microM, and TIs of 272 and >111, respectively. 2-Ethyl DCP (8) exhibited the best anti-HIV activity in both assays. Further development of 8-related compounds as clinical trial candidates is warranted.

  1. Liquid Ventilation

    Directory of Open Access Journals (Sweden)

    Qutaiba A. Tawfic

    2011-01-01

    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.

  2. Time-Resolved Soft X-ray Diffraction Reveals Transient Structural Distortions of Ternary Liquid Crystals

    Directory of Open Access Journals (Sweden)

    Klaus Mann

    2009-11-01

    Full Text Available Home-based soft X-ray time-resolved scattering experiments with nanosecond time resolution (10 ns and nanometer spatial resolution were carried out at a table top soft X-ray plasma source (2.2–5.2 nm. The investigated system was the lyotropic liquid crystal C16E7/paraffin/glycerol/formamide/IR 5. Usually, major changes in physical, chemical, and/or optical properties of the sample occur as a result of structural changes and shrinking morphology. Here, these effects occur as a consequence of the energy absorption in the sample upon optical laser excitation in the IR regime. The liquid crystal shows changes in the structural response within few hundred nanoseconds showing a time decay of 182 ns. A decrease of the Bragg peak diffracted intensity of 30% and a coherent macroscopic movement of the Bragg reflection are found as a response to the optical pump. The Bragg reflection movement is established to be isotropic and diffusion controlled (1 μs. Structural processes are analyzed in the Patterson analysis framework of the time-varying diffraction peaks revealing that the inter-lamellar distance increases by 2.7 Å resulting in an elongation of the coherently expanding lamella crystallite. The present studies emphasize the possibility of applying TR-SXRD techniques for studying the mechanical dynamics of nanosystems.

  3. Time-resolved soft X-ray diffraction reveals transient structural distortions of ternary liquid crystals.

    Science.gov (United States)

    Quevedo, Wilson; Peth, Christian; Busse, Gerhard; Scholz, Mirko; Mann, Klaus; Techert, Simone

    2009-11-04

    Home-based soft X-ray time-resolved scattering experiments with nanosecond time resolution (10 ns) and nanometer spatial resolution were carried out at a table top soft X-ray plasma source (2.2-5.2 nm). The investigated system was the lyotropic liquid crystal C(16)E(7)/paraffin/glycerol/formamide/IR 5. Usually, major changes in physical, chemical, and/or optical properties of the sample occur as a result of structural changes and shrinking morphology. Here, these effects occur as a consequence of the energy absorption in the sample upon optical laser excitation in the IR regime. The liquid crystal shows changes in the structural response within few hundred nanoseconds showing a time decay of 182 ns. A decrease of the Bragg peak diffracted intensity of 30% and a coherent macroscopic movement of the Bragg reflection are found as a response to the optical pump. The Bragg reflection movement is established to be isotropic and diffusion controlled (1 micros). Structural processes are analyzed in the Patterson analysis framework of the time-varying diffraction peaks revealing that the inter-lamellar distance increases by 2.7 A resulting in an elongation of the coherently expanding lamella crystallite. The present studies emphasize the possibility of applying TR-SXRD techniques for studying the mechanical dynamics of nanosystems.

  4. Phase behavior and ionic conductivity of concentrated solutions of polystyrene-poly(ethylene oxide) diblock copolymers in an ionic liquid.

    Science.gov (United States)

    Simone, Peter M; Lodge, Timothy P

    2009-12-01

    Concentrated solutions of poly(styrene-b-ethylene oxide) (PS-PEO) diblock copolymers were prepared using the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [EMI][TFSI] as the solvent. The self-assembled microstructures adopted by the copolymer solutions have been characterized using small-angle X-ray scattering. Lyotropic mesophase transitions were observed, with a progression from hexagonally packed cylinders of PEO, to lamellae, to hexagonally packed cylinders of PS upon increasing [EMI][TFSI] content. The change in lamellar domain spacing with ionic liquid concentration was found to be comparable to that reported for other block copolymers in strongly selective solvents. The ionic conductivity of the concentrated PS-PEO/[EMI][TFSI] solutions was measured via impedance spectroscopy, and ranged from 1 x 10(-7) to 1 x 10(-3) S/cm at temperatures from 25 - 100 degrees C. Additionally, the ionic conductivity of the solutions was found to increase with both ionic liquid concentration and molecular weight of the PEO blocks. The ionic conductivity of PEO homopolymer/[EMI][TFSI] solutions was also measured in order to compare the conductivity of the PS-PEO solutions to the expected limit for a lamellar sample with randomly oriented microstructure grains.

  5. Chiral front propagation in liquid-crystalline materials: Formation of the planar monodomain twisted plywood architecture of biological fibrous composites.

    Science.gov (United States)

    De Luca, Gino; Rey, Alejandro D

    2004-01-01

    Biological fibrous composites commonly exhibit an architecture known as twisted plywood, which is similar to that of the cholesteric liquid-crystalline mesophases. The explanation for the structural similarity is that biological fibrous composites adopt a lyotropic cholesteric liquid-crystalline phase during their formation process. In this work, a mathematical model based on the Landau-de Gennes theory of liquid crystals has been developed to reproduce the process by which long chiral fibrous molecules form the twisted plywood structures observed in biological composites. The dynamics of the process was then further investigated by analytically solving a simplified version of the governing equations. Results obtained from the model are in good qualitative agreement with the theory of Neville [Biology of Fibrous Composites (Cambridge University Press, Cambridge, England, 1993)] who hypothesized the necessity of a constraining layer to lock the direction of the helical axis of the plywood in order to create a monodomain structure. Computational results indicate that the plywood architecture is obtained by a chiral front propagation process with a fully relaxed wake. The effects of chirality and concentration on the formation process kinetics are characterized.

  6. Subsidizing Liquidity

    DEFF Research Database (Denmark)

    Malinova, Katya; Park, Andreas

    2015-01-01

    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...

  7. Liquid pearls

    CERN Document Server

    Bremond, Nicolas; Bibette, Jérôme

    2010-01-01

    This fluid dynamics video reports how to form liquid core capsules having a thin hydrogel elastic membrane named liquid pearls. These fish-egg like structures are initially made of a millimetric liquid drop, aqueous or not, coated with an aqueous liquid film containing sodium alginate that gels once the double drop enters a calcium chloride bath. The creation of such pearls with micrometer thick membrane requires to suppress mixing until gelling takes place. Here, we show that superimposing a two dimensional surfactant precipitation at the interface confers a transient rigidity that can damp the shear induced instability at impact. Based on this, pearls containing almost any type of liquids can be created. The video focuses on the dynamics of the entry of the compound drop into the gelling bath.

  8. Ion Transport in Nanostructured Block Copolymer/Ionic Liquid Membranes

    Science.gov (United States)

    Hoarfrost, Megan Lane

    Incorporating an ionic liquid into one block copolymer microphase provides a platform for combining the outstanding electrochemical properties of ionic liquids with a number of favorable attributes provided by block copolymers. In particular, block copolymers thermodynamically self-assemble into well-ordered nanostructures, which can be engineered to provide a durable mechanical scaffold and template the ionic liquid into continuous ion-conducting nanochannels. Understanding how the addition of an ionic liquid affects the thermodynamic self-assembly of block copolymers, and how the confinement of ionic liquids to block copolymer nanodomains affects their ion-conducting properties is essential for predictable structure-property control. The lyotropic phase behavior of block copolymer/ionic liquid mixtures is shown to be reminiscent of mixtures of block copolymers with selective molecular solvents. A variety of ordered microstructures corresponding to lamellae, hexagonally close-packed cylinders, body-centered cubic, and face-centered cubic oriented micelles are observed in a model system composed of mixtures of imidazolium bis(trifluoromethylsulfonyl)imide ([Im][TFSI]) and poly(styrene- b-2-vinyl pyridine) (PS-b-P2VP). In contrast to block copolymer/molecular solvent mixtures, the interfacial area occupied by each PS-b-P2VP chain decreases upon the addition of [Im][TFSI], indicating a considerable increase in the effective segregation strength of the PS-b-P2VP copolymer with ionic liquid addition. The relationship between membrane structure and ionic conductivity is illuminated through the development of scaling relationships that describe the ionic conductivity of block copolymer/ionic liquid mixtures as a function of membrane composition and temperature. It is shown that the dominant variable influencing conductivity is the overall volume fraction of ionic liquid in the mixture, which means there is incredible freedom in designing the block copolymer architecture

  9. Les polymères auto-renforcés à cristaux liquides Self-Reinforcing Liquid-Crystal Polymers

    Directory of Open Access Journals (Sweden)

    Dorbon M.

    2006-11-01

    Full Text Available Les polymères auto-renforcés à cristaux liquides (PARCL sont des matériaux dont les molécules, des polymères organiques, sont susceptibles de s'auto-orienter les unes par rapport aux autres. Cette propriété leur confère des caractéristiques mécaniques proches de celles des acier: pour des poids plus faibles sans qu'il soit nécessaire d'avoir recours à des fibres renforçantes. Il existe deux types de PARCL: ceux pouvant s'orienter en solution, qualifiés de lyotropiques, et ceux pouvant s'orienter à l'état fondu, appelés thermotropiques. Des fibres en poly (p-phénylène térephtalamide PPT, PARCL de type lyotropique, sont disponibles commercialement et connaissent déjà de nombreuses applications. Les PARCL thermotropiques n'existent pas encore sur le marché mais sont porteurs de nombreux espoirs car ils sont susceptibles d'être moulés et donc de prendre les formes les plus diverses, ce qui n'est pas le cas de ceux de type lyotropique. Self-reinforcing liquid-crystal polymers are materials in which the molecules, i. e. organic polymers, are capable of orienting themselves in relation to one another. This property gives them mechanical characteristics close to those of steels yet of much less weight without having to use reinforcing fibers. There are two types of self-reinforcing liquid-crystal polymers: (i those capable of orienting themselves in solution, called Iyotropic, and (ii those capable of orienting themselves in a molten state, called thermotropic. Poly (p-phenylene terephthalamide fibers, self-reinforcing liquid-crystal polymers of the Iyotropic type, are commercially available and have already found numerous applications. Thermotropic self-reinforcing liquid-crystal polymers are not yet on the market but seem to be very promising because they are capable of being molded and hence of taking on a wide variety of shapes, which is not the case of those of the lyotropic type.

  10. Managing liquidity

    DEFF Research Database (Denmark)

    Pokutta, Sebastian; Schmaltz, Christian

    2011-01-01

    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...... 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...

  11. Lyotropic liquid crystal used as drug delivery systems of controlled release%GMO/F127溶致液晶作为控释药物载体的研究

    Institute of Scientific and Technical Information of China (English)

    刘治镇; 赵静; 廖光熙; 刘芳娥; 张虎勤; 杜建强; 刘晓刚; 吴晓明; 林松

    2016-01-01

    目的:研究甘油单油酸酯/泊洛沙姆F127 (GMO/F127)溶致液晶作为控释药物的载体.方法:采用热处理法和乳化法,制备GMO/F127溶致液晶,研究了GMO/F127溶致液晶流体力学等物理特性.设计并完成溶致液晶担载不同极性药物体内和体外实验.采用分子模拟生物信息学方法研究了分子间相互作用.结果:制备了甘油单油酸酯/泊洛沙姆F127 (GMO/F127)溶致液晶,无论对于水溶性药物还是脂溶性药物,GMO/F127溶致液晶都具有缓释作用,且对于2种药物的释放率都较高.脉冲电场控释对小鼠血糖影响的实验显示,胰岛素包裹的粒子具有良好的电场响应性.结论:GMO/F127溶致液晶粒径较小,同时具有较大的比表面积,能够作为一种优良的药物载体.GMO/F127溶致液晶担载药物的释放过程平稳而长效,并且能够在电场效应的刺激下将药物迅速释放出去.

  12. Study of Ordering for AOT/Water Lamellar Lyotropic Liquid Crystal: Small-angle X-ray Scattering Experiments%小角X射线散射表征AOT/水层状溶致液晶的有序性

    Institute of Scientific and Technical Information of China (English)

    庄文昌; 陈晓; 杨春杰; 王庐岩; 柴永存

    2005-01-01

    用小角X射线散射研究了AOT/水层状溶致液晶的有序性.通过对散射曲线的解析,讨论了表面活性剂浓度、温度和助表面活性剂等三个方面对溶致液晶层状相结构有序性的影响.在一定的范围内,提高温度,改变表面活性剂浓度和加入少量助表面活性剂可使碳氢链排列由稀疏转变为密实,层状相也相应地由"柔性双层"过渡到更加有序化的"平面双层".基于形状因子和体系内分子间作用力,提出了层状相形成与有序化的机理,同时采用分子模拟的方法展现了不同浓度下的液晶结构.%Small-angle X-ray scattering (SAXS) is utilized to study the ordering of AOT/water lamellar phase. As increasing surfactant concentration, temperature or adding cosurfactant in certain range, the arrangement of hydrocarbon chains will change from sparse to dense which results in the structural transformation of lamellar phase from "flexible"to "planar" bilayers. The possible mechanism is proposed based on shape factor and molecular interactions. Molecular simulations are also carried out to testify the obtained results.

  13. Liquid explosives

    CERN Document Server

    Liu, Jiping

    2015-01-01

    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. Instability of a Biaxial Nematic Liquid Crystal Formed by Homeotropic Anchoring on Surface Grooves

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhi-Dong; XUAN Li

    2011-01-01

    A method used to treat the elastic distortion of a uniaxial nematic liquid crystal induced by homogeneous anchoring on the surface grooves is generalized to biaxial nematic liquid crystals under the homeotropic anchoring condition.Employing some approximations for the elastic constants,we obtain an additional term in the elastic energy per unit area which depends on the angle between the minor director at infinity and the direction of the grooves,with a period of π/2.This leads to instability on the surface grooves so that two states with crossed minor directors are energetically indistinguishable.Our theoretical study explains why the homeotropic alignment method developed for uniaxial liquid crystals loses efficacy for biaxial nematics.In most liquid crystal devices,the liquid crystals are sandwiched between two substrates coated with alignment layers.In the absence of externally applied fields,the orientation of the liquid crystal in the cell is determined by the anchoring condition of the alignment layer.[1-3] One usually distinguishes three main types of liquid crystalline director alignment near solid walls:homeotropic,homogeneous (or planar) and tilted orientations.Here we study the first of these and consider the biaxial nematic phase,which was observed in lyotropic systems as early as 1980[4] and has been confirmed by deuterium NMR spectroscopy.%A method used to treat the elastic distortion of a uniaxial nematic liquid crystal induced by homogeneous anchoring on the surface grooves is generalized to biaxial nematic liquid crystals under the homeotropic anchoring condition. Employing some approximations for the elastic constants, we obtain an additional term in the elastic energy per unit area which depends on the angle between the minor director at infinity and the direction of the grooves, with a period of π/2. This leads to instability on the surface grooves so that two states with crossed minor directors are energetically indistinguishable. Our

  15. Interactions of biomacromolecules with reverse hexagonal liquid crystals: drug delivery and crystallization applications.

    Science.gov (United States)

    Libster, Dima; Aserin, Abraham; Garti, Nissim

    2011-04-15

    Recently, self-assembled lyotropic liquid crystals (LLCs) of lipids and water have attracted the attention of both scientific and applied research communities, due to their remarkable structural complexity and practical potential in diverse applications. The phase behavior of mixtures of glycerol monooleate (monoolein, GMO) was particularly well studied due to the potential utilization of these systems in drug delivery systems, food products, and encapsulation and crystallization of proteins. Among the studied lyotropic mesophases, reverse hexagonal LLC (H(II)) of monoolein/water were not widely subjected to practical applications since these were stable only at elevated temperatures. Lately, we obtained stable H(II) mesophases at room temperature by incorporating triacylglycerol (TAG) molecules into the GMO/water mixtures and explored the physical properties of these structures. The present feature article summarizes recent systematic efforts in our laboratory to utilize the H(II) mesophases for solubilization, and potential release and crystallization of biomacromolecules. Such a concept was demonstrated in the case of two therapeutic peptides-cyclosporin A (CSA) and desmopressin, as well as RALA peptide, which is a model skin penetration enhancer, and eventually a larger macromolecule-lysozyme (LSZ). In the course of the study we tried to elucidate relationships between the different levels of organization of LLCs (from the microstructural level, through mesoscale, to macroscopic level) and find feasible correlations between them. Since the structural properties of the mesophase systems are a key factor in drug release applications, we investigated the effects of these guest molecules on their conformations and the way these molecules partition within the domains of the mesophases. The examined H(II) mesophases exhibited great potential as transdermal delivery vehicles for bioactive peptides, enabling tuning the release properties according to their chemical

  16. Liquid Crystals

    Science.gov (United States)

    1990-01-01

    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.

  17. Formation and characteristics of aqueous two-phase systems formed by a cationic surfactant and a series of ionic liquids.

    Science.gov (United States)

    Wei, Xi-Lian; Wang, Xiu-Hong; Ping, A-Li; Du, Pan-Pan; Sun, De-Zhi; Zhang, Qing-Fu; Liu, Jie

    2013-11-15

    Aqueous two-phase systems (ATPS) were obtained in the aqueous mixtures of a cationic surfactant and a series of ionic liquids (ILs). The effects of IL structure, temperature and additives on the phase separation were systematically investigated. The microstructures of some ATPS were observed by freeze-fracture replication technique. Lyotropic liquid crystal was found in the bottom phase besides micelles under different conditions. Remarkably, both IL structure and additives profoundly affected the formation and properties of the ATPSs. The phase separation can be attributed to the existence of different aggregates and the cation-π interactions of the cationic surfactant with the ILs, which has a significant role in the formation of ATPS. The extraction capacity of the studied ATPS was also evaluated through their application in the extraction of two biosubstances. The results indicate that the ILs with BF4(-) as anion show much better extraction efficiencies than the corresponding ILs with Br(-) as anion do under the same conditions. l-Tryptophan was mainly distributed into the NPTAB-rich phase, while methylene blue and capsochrome were mainly in the IL-rich phase.

  18. Liquid acrobatics

    CERN Document Server

    Bird, James C

    2008-01-01

    We experiment with injecting a continuous stream of gas into a shallow liquid, similar to how one might blow into a straw placed at the bottom of a near-empty drink. By varying the angle of the straw (here a metal needle), we observe a variety of dynamics, which we film using a high-speed camera. Most noteworthy is an intermediate regime in which cyclical jets erupt from the air-liquid interface and breakup into air-born droplets. These droplets trace out a parabolic trajectory and bounce on the air-liquid interface before eventually coalescing. The shape of each jet, as well as the time between jets, is remarkably similar and leads to droplets with nearly identical trajectories. The following article accompanies the linked fluid dynamics video submitted to the Gallery of Fluid Motion in 2008.

  19. Antitumor agents 286. Design, synthesis, and structure-activity relationships of 3'R,4'R-disubstituted-2',2'-dimethyldihydropyrano[2,3-f]chromone (DSP) analogues as potent chemosensitizers to overcome multidrug resistance.

    Science.gov (United States)

    Zhou, Ting; Shi, Qian; Bastow, Kenneth F; Lee, Kuo-Hsiung

    2010-12-23

    In this study, various 3'R,4'R-disubstituted-2',2'-dimethydihydropyrano[2,3-f]chromone (DSP) derivatives were discovered as potent chemosensitizers in the treatment of multidrug resistant cancer cells. Twenty-four DSP analogues (5-28) were synthesized and evaluated against a multidrug resistant (MDR) cell line (KB-Vin) with and without vincristine (VCR). All DSP analogues exhibited low intrinsic cytotoxicity. However, in combination treatment, most DSPs reversed resistance to VCR and lowered the GI₅₀ value of VCR by 12-349-fold. At a concentration of 1 μg/mL, three compounds, 11, 14, and 21, fully reversed resistance to VCR in KB-Vin cancer cells, a 2-fold increase compared to verapamil, a first-generation chemosensitizer. Detailed structure-activity relationship (SAR) conclusions were established based on 3' and 4' substitutions. Moreover, a preliminary mechanism study indicated that the chemosensitizing activity of DSP analogues results from inhibition of P-glycoprotein (P-gp) overexpressed in MDR cancer cells.

  20. GYF-17, a chloride substituted 2-(2-phenethyl)-chromone, suppresses LPS-induced inflammatory mediator production in RAW264.7 cells by inhibiting STAT1/3 and ERK1/2 signaling pathways.

    Science.gov (United States)

    Zhu, Zhixiang; Gu, Yufan; Zhao, Yunfang; Song, Yuelin; Li, Jun; Tu, Pengfei

    2016-06-01

    GYF-17, a 2-(2-phenethyl)-chromone derivative, was isolated from agarwood and showed superior activity of inhibiting NO production of RAW264.7 cells induced by LPS in our preliminary pharmacodynamic screening. In order to develop novel therapeutic drug for acute and chronic inflammatory disorders, the anti-inflammatory activity and underlying mechanism of GYF-17 were investigated in LPS-induced RAW264.7 cells. The results showed that GYF-17 could reduce LPS-induced expression of iNOS and then result in the decrement of NO production. More meaningful, the expression and secretion of key pro-inflammatory factors, including TNF-α, IL-6 and IL-1β, were intensively inhibited by GYF-17. Furthermore, GYF-17 also down regulated the expression of COX2 and the production of PGE2 which plays important role in causing algesthesia during inflammatory response. In mechanism study, GYF-17 selectively suppressed phosphorylation of STAT1/3 and ERK1/2 during the activation of NF-κB, MAPK and STAT signaling pathways induced by LPS. Collectively, GYF-17 can intensively suppress the production of LPS-induced inflammatory mediators in RAW264.7 cells by inhibiting STAT1/3 and ERK1/2 signaling pathways and thereby shows great potential to be developed into therapeutic drug for inflammatory diseases. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Synthesis, characterization, and antioxidant/cytotoxic activity of new chromone Schiff base nano-complexes of Zn(II), Cu(II), Ni(II) and Co(II)

    Science.gov (United States)

    Saif, M.; El-Shafiy, Hoda F.; Mashaly, Mahmoud M.; Eid, Mohamed F.; Nabeel, A. I.; Fouad, R.

    2016-08-01

    A chromone Schiff base complexes of Zn(II) (1), Cu(II) (2), Ni(II) (3) and Co(II) (4) were successfully prepared in nano domain with crystalline or amorphous structures. The spectroscopic data revealed that the Schiff base ligand behaves as a monoanionic tridentate ligand. The metal complexes exhibited octahedral geometry. Transmission electron microscope (TEM) analysis showed that Cu(II) complex have aggregated nanospheres morphology. The obtained nano-complexes were tested as antioxidant and antitumor agents. The H2L and its Cu(II) complex (2) were found to be more potent antioxidant (IC50(H2L) = 0.93 μM; IC50(Cu(II) complex) = 1.1 μM than standard ascorbic acid (IC50 = 2.1 μM) as evaluated by DPPH• method. The H2L and its complexes (1-4) were tested for their in vitro cytotoxicity against Ehrlich Ascites Carcinoma cell line (EAC). The Cu(II) nano-complex (2) effectively inhibited EAC growth with IC50 value of 47 μM in comparison with its parent compound and other prepared complexes. The high antioxidant activity and antitumor activity of Cu(II) nano-complex (2) were attributed to their chemical structure, Cu(II) reducing capacity, and nanosize property. The toxicity test on mice showed that Zn(II) (1) and Cu(II) (2) nano-complex have lower toxicity than the standard cis-platin.

  2. GYF-21, an Epoxide 2-(2-Phenethyl-Chromone Derivative, Suppresses Innate and Adaptive Immunity via Inhibiting STAT1/3 and NF-κB Signaling Pathways

    Directory of Open Access Journals (Sweden)

    Ran Guo

    2017-05-01

    Full Text Available Multiple sclerosis is a chronic inflammatory autoimmune disease of the central nervous system characterized by demyelinating plaques and axonal loss. Inhibition on over activation of innate and adaptive immunity provides a rationale strategy for treatment of multiple sclerosis. In the present study, we investigated the inhibitory effects of GYF-21, an epoxide 2-(2-phenethyl-chromone derivative isolated from Chinese agarwood, on innate and adaptive immunity for revealing its potential to treat multiple sclerosis. The results showed that GYF-21 markedly inhibited the activation of microglia, and dendritic cells as well as neutrophils, all of which play important roles in innate immunity. Furthermore, GYF-21 significantly suppressed adaptive immunity via inhibiting the differentiation of naive CD4+ T cells into T helper 1 (Th1 and T helper 17 (Th17 cells, and suppressing the activation, proliferation, and IFN-γ secretion of CD8+ T cells. The mechanism study showed that GYF-21 evidently inhibited the activation of STAT1/3 and NF-κB signaling pathways in microglia. In conclusion, we demonstrated that GYF-21 can significantly inhibit innate and adaptive immunity via suppressing STAT1/3 and NF-κB signaling pathways, and has potential to be developed into therapeutic drug for multiple sclerosis.

  3. Synthesis, characterization and biological activity of some new VO(IV), Co(II), Ni(II), Cu(II) and Zn(II) complexes of chromone based NNO Schiff base derived from 2-aminothiazole

    Science.gov (United States)

    Kalanithi, M.; Kodimunthiri, D.; Rajarajan, M.; Tharmaraj, P.

    2011-11-01

    Coordination compounds of VO(IV), Co(II), Ni(II), Cu(II) and Zn(II) with the Schiff base obtained through the condensation of 2-aminothiazole with 3-formyl chromone were synthesized. The compounds were characterized by 1H, 13C NMR, UV-Vis, IR, Mass, EPR, molar conductance and magnetic susceptibility measurements. The Cu(II) complex possesses tetrahedrally distorted square planar geometry whereas Co(II), Ni(II), and Zn(II) show distorted tetrahedral geometry. The VO(IV) complex shows square pyramidal geometry. The cyclic voltammogram of Cu (II) complex showed a well defined redox couple Cu(II)/Cu(I) with quasireversible nature. The antimicrobial activity against the species Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Candida albigans and Aspergillus niger was screened and compared to the activity of the ligand. Emission spectrum was recorded for the ligand and the metal(II) complexes. The second harmonic generation (SHG) efficiency was measured and found to have one fourth of the activity of urea. The SEM image of the copper(II) complex implies that the size of the particles is 2 μm.

  4. Macromolecular liquids

    Energy Technology Data Exchange (ETDEWEB)

    Safinya, C.R.; Safran, S.A. (Exxon Research and Engineering Co., Annandale, NJ (US)); Pincus, P.A. (Univ. of California at Santa Barbara, Santa Barbara, CA (US))

    1990-01-01

    Liquids include a broad range of material systems which are of high scientific and technological interest. Generally speaking, these are partially ordered or disordered phases where the individual molecular species have organized themselves on length scales which are larger than simple fluids, typically between 10 Angstroms and several microns. The specific systems reported on in this book include membranes, microemulsions, micelles, liquid crystals, colloidal suspensions, and polymers. They have a major impact on a broad spectrum of technological industries such as displays, plastics, soap and detergents, chemicals and petroleum, and pharmaceuticals.

  5. Liquid Marbles

    KAUST Repository

    Khalil, Kareem

    2012-12-01

    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

  6. Liquid/liquid heat exchanger

    Science.gov (United States)

    Miller, C. G.

    1980-01-01

    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.

  7. Chiral liquids

    Directory of Open Access Journals (Sweden)

    Zakharov V.I.

    2015-01-01

    Full Text Available We review briefly properties of chiral liquids, or liquids with massless fermionic constituents. We concentrate on three effects, namely, the low ratio of viscosity η to entropy density s, chiral magnetic and vortical effects. We sketch standard derivations of these effects in the hydrodynamic approximation and then concentrate on possibile unifying approach which is based on consideration of the (anomalously conserved axial current. The point is that the conservation of chirality is specific for the microscopic, field-theoretic description of massless fermions and their interactions. On the macroscopic side, the standard hydrodynamic equations are not consistent, generally speaking, with conservation of a helical macroscopic motion. Imposing extra constraints on the hydrodynamics might resolve this “clash-of-symmetries” paradox.

  8. Liquid helium

    CERN Document Server

    Atkins, K R

    1959-01-01

    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.

  9. Pump for Saturated Liquids

    Science.gov (United States)

    Elliott, D. G.

    1986-01-01

    Boiling liquids pumped by device based on proven components. Expanding saturated liquid in nozzle and diverting its phases along separate paths in liquid/vapor separator raises pressure of liquid. Liquid cooled in process. Pump makes it unnecessary to pressurize cryogenic liquids in order to pump them. Problems of introducing noncondensable pressurizing gas avoided.

  10. Mechanistic insights into a novel chromone-appended Cu(II) anticancer drug entity: in vitro binding profile with DNA/RNA substrates and cytotoxic activity against MCF-7 and HepG2 cancer cells.

    Science.gov (United States)

    Yousuf, Imtiyaz; Arjmand, Farukh; Tabassum, Sartaj; Toupet, Loic; Khan, Rais Ahmad; Siddiqui, Maqsood Ahmad

    2015-06-14

    A new chromone-appended Cu(ii) drug entity () was designed and synthesized as a potential anticancer chemotherapeutic agent. The structural elucidation was carried out thoroughly by elemental analysis, FT-IR, EPR, ESI-MS and single crystal X-ray crystallography. Complex resulted from the in situ methoxylation reaction of the 3-formylchromone ligand and its subsequent complexation with the copper nitrate salt in a 2 : 1 ratio, respectively. crystallized in the monoclinic P21/c space group possessing the lattice parameters, a = 8.75 Å, b = 5.07 Å, c = 26.22 Å, α = γ = 90°, β = 96.3° per unit cell. Furthermore, in vitro interaction studies of with ct-DNA and tRNA were carried out which suggested more avid binding propensity towards the RNA target via intercalative mode, which was reflected from its Kb, K and Ksv values. The gel electrophoretic mobility assay was carried out on the pBR322 plasmid DNA substrate, to ascertain the cleaving ability and the mechanistic pathway in the presence of additives, and the results revealed the efficient cleaving ability of via the oxidative pathway. In vitro cell growth inhibition via the MTT assay was carried out to evaluate the cytotoxicity of complex and IC50 values were found to be in the range of 5-10 μg mL(-1) in HepG2 and MCF-7 cancer cell lines, which were found to be much lower than the IC50 values of previously reported similar Cu(ii) complexes. Additionally, in the presence of , reactive oxygen species (ROS) and thiobarbituric acid reactive substance (TBARS) levels in the tested cancer cell lines increased significantly, coupled with reduced glutathione (GSH) levels. Thus, our results suggested that ROS plays an important role in cell apoptosis induced by the Cu(ii) complex and validates its potential to act as a robust anticancer drug entity.

  11. Liquid Ventilation

    Directory of Open Access Journals (Sweden)

    Peter N Cox

    1996-01-01

    Full Text Available There has been a recent explosion of interest in the use of liquid ventilation. Over time humans have lost the physiological attributes necessary for respiration in water. However, perfluorocarbons have high solubilities for oxygen and carbon dioxide, as well as a low surface tension. These characteristics allow them to be used as a medium to assist gas exchange and recruit atelectatic-dependent lung zones in respiratory distress syndrome. Current trials may prove perfluorocarbon to be a useful adjunct in lung protective strategies in respiratory distress syndrome.

  12. Bismuth-ceramic nanocomposites through ball milling and liquid crystal synthetic methods

    Science.gov (United States)

    Dellinger, Timothy Michael

    Three methods were developed for the synthesis of bismuth-ceramic nanocomposites, which are of interest due to possible use as thermoelectric materials. In the first synthetic method, high energy ball milling of bismuth metal with either MgO or SiO2 was found to produce nanostructured bismuth dispersed on a ceramic material. The morphology of the resulting bismuth depended on its wetting behavior with respect to the ceramic: the metal wet the MgO, but did not wet on the SiO2. Differential Scanning Calorimetry measurements on these composites revealed unusual thermal stability, with nanostructure retained after multiple cycles of heating and cooling through the metal's melting point. The second synthesis methodology was based on the use of lyotropic liquid crystals. These mixtures of water and amphiphilic molecules self-assemble to form periodic structures with nanometer-scale hydrophilic and hydrophobic domains. A novel shear mixing methodology was developed for bringing together reactants which were added to the liquid crystals as dissolved salts. The liquid crystals served to mediate synthesis by acting as nanoreactors to confine chemical reactions within the nanoscale domains of the mesophase, and resulted in the production of nanoparticles. By synthesizing lead sulfide (PbS) and bismuth (Bi) particles as proof-of-concept, it was shown that nanoparticle size could be controlled by controlling the dimensionality of the nanoreactors through control of the liquid crystalline phase. Particle size was shown to decrease upon going from three-dimensionally percolating nanoreactors, to two dimensional sheet-like nanoreactors, to one dimensional rod-like nanoreactors. Additionally, particle size could be controlled by varying the precursor salt concentration. Since the nanoparticles did not agglomerate in the liquid crystal immediately after synthesis, bismuth-ceramic nanocomposites could be prepared by synthesizing Bi nanoparticles and mixing in SiO2 particles which

  13. Microstructure evaluation of dermally applicable liquid crystals as a function of water content and temperature: Can electron paramagnetic resonance provide complementary data?

    Science.gov (United States)

    Matjaž, Mirjam Gosenca; Mravljak, Janez; Rogač, Marija Bešter; Šentjurc, Marjeta; Gašperlin, Mirjana; Pobirk, Alenka Zvonar

    2017-05-18

    Insight into the microstructure of lyotropic liquid crystals (LCs) is of crucial importance for development of novel dermal delivery systems. Our aim was to evaluate the phase behaviour of dermally applicable LCs composed of isopropyl myristate/Tween 80/lecithin/water, along the dilution line, where phase transitions are predominantly driven by increased water content. Additionally, identification of LC temperature dependence is of great importance for skin application. Selected LCs were evaluated using electron paramagnetic resonance (EPR) plus conventionally used methods of polarization microscopy, small-angle X-ray scattering, differential scanning calorimetry, and rheological measurements. Depending on water content, LCs formed diverse microstructures, from (pseudo)hexagonal (LC1) and lamellar (LC2-LC7) liquid crystalline phases that possibly co-exist with rod-like micelles (LC4-LC7), to a transitional micellar phase (LC8). Furthermore, the LCs microstructure remained unaltered within the tested temperature range. EPR was shown to detect microstructural transitions of LCs and to provide complementary data to other techniques. These data thus confirm the applicability of EPR as a complementary technique for better understanding of LC microstructural transitions that are expected to contribute greatly to studies oriented towards the drug release characteristics from such systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. The Effect of Electroporation of a Lyotroic Liquid Crystal Genistein-Based Formulation in the Recovery of Murine Melanoma Lesions

    Directory of Open Access Journals (Sweden)

    Corina Danciu

    2015-07-01

    Full Text Available A lamellar lyotropic liquid crystal genistein-based formulation (LLC-Gen was prepared in order to increase the aqueous solubility of the lipophilic phytocompound genistein. The formulation was applied locally, in a murine model of melanoma, with or without electroporation. The results demonstrated that, when the formulation was applied by electroporation, the tumors appeared later. During the 21 days of the experiment, the LLC-Gen formulation decreased the tumor volume, the amount of melanin and the degree of erythema, but when electroporation was applied, all these parameters indicated a better prognosis even (lower tumor volume, amount of melanin and degree of erythema. Although hematoxylin–eosin (HE staining confirmed the above events, application of the LLC-Gen formulation by electroporation did not lead to a significant effect in terms of the serum concentrations of the protein S100B and serum neuron specific enolase (NSE, or the tissue expression of the platelet-derived growth factor receptor β (PDGFRβ antibody.

  15. From Funding Liquidity to Market Liquidity

    DEFF Research Database (Denmark)

    Dick-Nielsen, Jens; Lund, Jesper; Gyntelberg, Jacob

    This paper shows empirically that funding liquidity drives market liquidity. As it becomes harder to secure term funding in the money markets, liquidity deteriorates in the Danish bond market. We show that the first principal component of bond market liquidity is driven by the market makers' abil...... for other European government bonds using MTS data. The findings suggest that regulatory bond based liquidity buffers for banks will have limited effectiveness.......This paper shows empirically that funding liquidity drives market liquidity. As it becomes harder to secure term funding in the money markets, liquidity deteriorates in the Danish bond market. We show that the first principal component of bond market liquidity is driven by the market makers...

  16. Determination of Isoflavone Content in SRM 3238 Using Liquid Chromatography-Particle Beam/Electron Ionization Mass Spectrometry

    Science.gov (United States)

    Zhang, Lynn X.; Burdette, Carolyn Q.; Phillips, Melissa M.; Rimmer, Catherine A.; Marcus, R. Kenneth

    2016-01-01

    The characterization of marker components in botanical materials is a challenging task and the increased consumption of botanicals and dietary supplements demands a greater understanding of the associated health benefits and risks. In order to successfully acquire and compare clinical results and correlate health trends, accurate, precise, and validated methods of analysis must be developed. Presented here is the development of a quantitative method for the determination of soy isoflavones (daidzin, glycitin, genistin, daidzein, and genistein) using liquid chromatography-particle beam/electron ionization mass spectrometry (LC-PB/EIMS). An internal standard (IS) approach for quantitation using 7-hydroxy-4-chromone as the IS compound was employed, with response factors for each individual isoflavone obtained from calibrant solutions. The results from this method were compared with the certified and reference values for NIST SRM 3238 Soy-Containing Solid Oral Dosage Form to demonstrate that the method was in control. Results obtained using LC-PB/EIMS were consistent with the NIST certified or reference values and their uncertainties for all five isoflavones, demonstrating that the LC-PB/EIMS approach is both accurate and precise when used for the determination of the target isoflavones in soy-containing dietary supplement finished products, while simultaneously providing structural information. PMID:26651559

  17. Liquidation of the company

    OpenAIRE

    Procházka, Michal

    2011-01-01

    This work deals with the liquidation of the company focusing on commercial companies. It describes whole process of liquidation from decision to liquidate to delete the company from the Commercial Register. The work also focuses on legal, accounting and tax site of liquidation. Accounting practices in the liquidation process are illustrated on the example of a fictive company.

  18. The suppressive effects of Saposhnikovia divaricata (Fangfeng) chromone extract on rheumatoid arthritis via inhibition of nuclear factor-κB and mitogen activated proteinkinases activation on collagen-induced arthritis model.

    Science.gov (United States)

    Kong, Xiangying; Liu, Chunfang; Zhang, Cun; Zhao, Juan; Wang, Jianzhu; Wan, Hongye; Zhu, Hongwei; Zhang, Ping; Chen, Weiheng; Xiao, Yongqing; Lin, Na

    2013-07-30

    Saposhnikovia divaricata (SD), called "Fangfeng" in China, is commonly used in clinical compound prescription for treatment of rheumatoid arthritis (RA), but its actions on RA have not been clarified. The present study aims to determine the anti-inflammatory activity of SD chromone extract (SCE), the major bioactive component of SD, on collagen-induced arthritis (CIA) rats, and elucidate its underlying mechanisms with regards to its molecular basis of action on human fibroblast-like synoviocytes derived from RA patients (HFLS-RA). CIA model on rats was constructed by injection of bovine type II collagen. Rats were pre-treated with different dosages of SCE from 3 days before till 35 days after model building. The progression of CIA was evaluated by macroscopic scoring, X-ray observation and hematoxylin and eosin (HE) staining of paws. HFLS-RA were pre-treated with different concentrations of SCE prior to stimulation with 10 ng/ml of tumor necrosis factor (TNF) α. By radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA), levels of interleukin (IL)-1β, IL-6, TNFα and prostaglandin E2 (PGE2) were quantified respectively. Nuclear factor (NF-κB) p65 expression and DNA-binding activity were tested by immunohistochemisty and electrophoretic mobility shift assay (EMSA) respectively. Phosphorylation of extracellular signal-regulated kinase (ERK), Jun N-terminal kinase (JNK) and p38 MAPKs were examined by immunohistochemisty staining and western blot analysis. Histological examination and radiological observation demonstrated that SCE significantly reduced the inflammatory responses in the joints of CIA rats. SCE inhibited the production of TNFα, IL-1β, and IL-6 in the joint tissues and sera. The level of PGE2 in sera was also decreased by SCE. Moreover, SCE treatment in vivo was able to reduce protein level of NF-κB, the transcriptional factor closely related to the inflammatory process, in articular synovium and cartilage of CIA rats. In addition, SCE

  19. CASH AND LIQUIDITY/LIQUIDITY AND LIQUIDITY RATIO

    Directory of Open Access Journals (Sweden)

    BEATRIX LIGHEZAN BREUER

    2012-12-01

    Full Text Available The present paper aims to present the correlation as well as the differences between liquidity/cash and liquidity ratio in terms of economic entities. Researches on this topic are based on the opinions of some specialists in accounting and in the economic-financial analysis, as well as on the national legal stipulations and the ones set out in the International Accounting Standards, the Financial report, respectively. The object of this paper is represented by the correlation between liquidity/cash and liquidity ratios representing the liquidity as current assets, assets implied in the determination of liquidity ratios. The end of the paper consists of the conclusions drawn from the issues presented in the paper but also our views on this research topic.

  20. Liquidity risk management

    Directory of Open Access Journals (Sweden)

    Milošević Miloš

    2014-01-01

    Full Text Available Liquidity risk management is a major activity of every bank. To be able to honor its matured liabilities, a bank strives to provide and maintain the required level of liquidity on a daily basis. Although each commercial bank has its own methodology of calculating the required liquidity level, in line with its adopted policies, the central bank has enacted the Decision on Liquidity Risk Management, prescribing the obligatory liquidity risk management policy.

  1. Simultaneous qualitative and quantitative determination of phenolic compounds in Aloe barbadensis Mill by liquid chromatography-mass spectrometry-ion trap-time-of-flight and high performance liquid chromatography-diode array detector.

    Science.gov (United States)

    Wu, Xiaofang; Ding, Wenjing; Zhong, Jiasheng; Wan, Jinzhi; Xie, Zhiyong

    2013-06-01

    An effective and comprehensive method was developed for the simultaneous analysis of phenolic compounds in the dried exudate of Aloe barbadensis Mill by liquid chromatography-mass spectrometry-ion trap-time-of-flight (LCMS-IT-TOF) and high performance liquid chromatography-diode array detector (HPLC-DAD). Qualitative analysis of all the compounds presented in A. barbadensis Mill was performed on LCMS-IT-TOF, and the diagnostic fragmentation patterns of different types of phenolic compounds (chromones, phenyl pyrones, naphthalene derivative, anthrones and anthraquinones) were discussed on the basis of ESI-IT-TOF MS of components in A. barbadensis Mill and eleven authentic standards. Under the optimal HPLC-DAD chromatographic conditions, quantification of 11 typical phenolic compounds in 15 batches of A. barbadensis Mill was achieved on an Agilent TC-C18 column using gradient elution with a solvent system of methanol and water at a flow rate of 1.0mLmin(-1) and detected at 230nm. All calibration curves exhibited good linear relationship (r(2)>0.9991). The relative standard deviation values for intraday precision were less than 2% with accuracies between 98.21% and 104.57%. The recoveries of the eleven analytes ranged from 97.53 to 105.00% with RSDs less than 2%. This is the first simultaneous characterization and quantitative determination of multiple phenolic compounds in A. barbadensis Mill from locally grown cultivars in China by LCMS-IT-TOF and HPLC-DAD, which can be applied to standardize the quality of A. barbadensis Mill and the future design of nutraceutical and cosmetic preparations.

  2. Dynamics of liquid-liquid displacement.

    Science.gov (United States)

    Fetzer, Renate; Ramiasa, Melanie; Ralston, John

    2009-07-21

    Capillary driven liquid-liquid displacement in a system with two immiscible liquids of comparable viscosity was investigated by means of optical high speed video microscopy. For the first time, the impact of substrate wettability on contact line dynamics in liquid-liquid systems was studied. On all substrates, qualitatively different dynamics, in two distinct velocity regimes, were found. Hydrodynamic models apply to the fast stage of initial spreading, while nonhydrodynamic dissipation dominates contact line motion in a final stage at low speed, where the molecular kinetic theory (MKT) successfully captured the dynamics. The MKT model parameter values showed no systematic dependence on substrate wettability. This unexpected result is interpreted in terms of local contact line pinning.

  3. Liquid Effluent Retention Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Liquid Effluent Retention Facility (LERF) is located in the central part of the Hanford Site. LERF is permitted by the State of Washington and has three liquid...

  4. Liquid Drop Measuring Device for Analyzing Liquid Properties

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Based on the correlation between certain properties of liquid and the properties of the corresponding liquid drop formed under given conditions, a liquid drop measuring device is utilized to monitor the drop formation process of the liquid sample with photoelectric measuring methods. The mechanical and optical characteristic of the liquid is explored with the optical fibers from the internal of the liquid drop during its formation. The drop head capacitor is utilized to monitor the growth process of the liquid drop to gain the drop volume information related to the physical property of liquid. The unique liquid drop trace containing the integrated properties of liquid is generated, and it is proved by experiment that for different liquids their liquid drop traces are different. The analysis on liquid properties and discrimination between different liquids can be proceeded with the liquid drop trace obtained by the liquid drop measuring device.

  5. Global Liquidity Trap

    OpenAIRE

    Fujiwara, Ippei; NAKAJIMA Tomoyuki; Sudo, Nao; Teranishi, Yuki

    2011-01-01

    In this paper we consider a two-country New Open Economy Macroeconomics model, and analyze the optimal monetary policy when countries cooperate in the face of a "global liquidity trap" -- i.e., a situation where the two countries are simultaneously caught in liquidity traps. The notable features of the optimal policy in the face of a global liquidity trap are history dependence and international dependence. The optimality of history dependent policy is confirmed as in local liquidity trap. A ...

  6. Asset Class Liquidity Risk

    OpenAIRE

    Ronnie Sadka

    2014-01-01

    This paper studies liquidity risk, as measured by the covariation of returns with unexpected changes in aggregate liquidity, across 106 indices covering global equity, industry sectors, fixed income, and hedge funds. Roughly 20% of all sample indices, and over 50% of hedge-fund indices, display a significant exposure to liquidity risk. The annualized cross-sectional liquidity risk premium is estimated at about 2%. The results are robust to various controls and methodological choices. Practica...

  7. Fluid Mechanics of Liquid-Liquid Systems.

    Science.gov (United States)

    Richards, John Reed

    The detailed hydrodynamics of selected liquid -liquid flow systems are investigated to provide a firm foundation for the rational design of separation processes. The implementation of this objective centers on the development of a robust code to simulate liquid-liquid flows. We have applied this code to the realistic simulation of aspects of the complex fluid mechanical behavior, and developed quantitative insight into the underlying processes involved. The Volume of Fluid (VOF) method is combined with the Continuous Surface Force (CSF) algorithm to provide a numerically stable code capable of solving high Reynolds numbers free surface flows. One of the developments during the testing was an efficient method for solving the Young-Laplace equation describing the shape of the meniscus in a vertical cylinder for a constrained liquid volume. The steady-state region near the nozzle for the laminar flow of a Newtonian liquid jet injected vertically into another immiscible Newtonian liquid is investigated for various Reynolds numbers by solving the axisymmetric transient equations of motion and continuity. The analysis takes into account pressure, viscous, inertial, gravitational, and surface tension forces, and comparison with previous experimental measurements shows good agreement. Comparisons of the present numerical method with the numerical results of previous boundary-layer methods help establish their range of validity. A new approximate equation for the shape of the interface of the steady jet, based on an overall momentum balance, is also developed. The full transient from liquid-liquid jet startup to breakup into drops is also simulated numerically. In comparison with experiment, the results of the present numerical method show a greater sensitivity of the jet length to the Reynolds number than the best predictions of previous linear stability analyses. The formation of drops is investigated at low to high Reynolds numbers before and after jet formation. The

  8. Liquid/liquid/solid contact angles

    Science.gov (United States)

    Borocco, Marine; Pellet, Charlotte; Authelin, Jean-René; Clanet, Christophe; Quéré, David; Compagnie des Interfaces Team

    2016-11-01

    Many studies have investigated solid/liquid/air interfaces and their corresponding wetting properties. We discuss what happens in less-studied liquid/liquid/solid systems, and focus on questions of dynamical wetting in a tube, having in mind applications in detergency. We use a capillary tube filled with water and containing a slug of silicone oil (or vice-versa), and present a series of experiments to determine static and dynamic wetting properties corresponding to this situation. We also discuss interfacial aging of such systems.

  9. Liquid Wall Chambers

    Energy Technology Data Exchange (ETDEWEB)

    Meier, W R

    2011-02-24

    The key feature of liquid wall chambers is the use of a renewable liquid layer to protect chamber structures from target emissions. Two primary options have been proposed and studied: wetted wall chambers and thick liquid wall (TLW) chambers. With wetted wall designs, a thin layer of liquid shields the structural first wall from short ranged target emissions (x-rays, ions and debris) but not neutrons. Various schemes have been proposed to establish and renew the liquid layer between shots including flow-guiding porous fabrics (e.g., Osiris, HIBALL), porous rigid structures (Prometheus) and thin film flows (KOYO). The thin liquid layer can be the tritium breeding material (e.g., flibe, PbLi, or Li) or another liquid metal such as Pb. TLWs use liquid jets injected by stationary or oscillating nozzles to form a neutronically thick layer (typically with an effective thickness of {approx}50 cm) of liquid between the target and first structural wall. In addition to absorbing short ranged emissions, the thick liquid layer degrades the neutron flux and energy reaching the first wall, typically by {approx}10 x x, so that steel walls can survive for the life of the plant ({approx}30-60 yrs). The thick liquid serves as the primary coolant and tritium breeding material (most recent designs use flibe, but the earliest concepts used Li). In essence, the TLW places the fusion blanket inside the first wall instead of behind the first wall.

  10. Acidic Ionic Liquids.

    Science.gov (United States)

    Amarasekara, Ananda S

    2016-05-25

    Ionic liquid with acidic properties is an important branch in the wide ionic liquid field and the aim of this article is to cover all aspects of these acidic ionic liquids, especially focusing on the developments in the last four years. The structural diversity and synthesis of acidic ionic liquids are discussed in the introduction sections of this review. In addition, an unambiguous classification system for various types of acidic ionic liquids is presented in the introduction. The physical properties including acidity, thermo-physical properties, ionic conductivity, spectroscopy, and computational studies on acidic ionic liquids are covered in the next sections. The final section provides a comprehensive review on applications of acidic ionic liquids in a wide array of fields including catalysis, CO2 fixation, ionogel, electrolyte, fuel-cell, membrane, biomass processing, biodiesel synthesis, desulfurization of gasoline/diesel, metal processing, and metal electrodeposition.

  11. Critical Phenomena in Liquid-Liquid Mixtures

    Science.gov (United States)

    Jacobs, D. T.

    2000-04-01

    Critical phenomena provide intriguing and essential insight into many issues in condensed matter physics because of the many length scales involved. Large density or concentration fluctuations near a system's critical point effectively mask the identity of the system and produce universal phenomena that have been well studied in simple liquid-vapor and liquid-liquid systems. Such systems have provided useful model systems to test theoretical predictions which can then be extended to more complicated systems. Along various thermodynamic paths, several quantities exhibit a simple power-law dependence close to the critical point. The critical exponents describing these relationships are universal and should depend only on a universality class determined by the order-parameter and spatial dimensionality of the system. Liquid gas, binary fluid mixtures, uniaxial ferromagnetism, polymer-solvent, and protein solutions all belong to the same (Ising model) universality class. The diversity of critical systems that can be described by universal relations indicates that experimental measurements on one system should yield the same information as on another. Our experimental investigations have tested existing theory and also extended universal behavior into new areas. By measuring the coexistence curve, heat capacity, thermal expansion and static light scattering (turbidity) in various liquid-liquid and polymer-solvent systems, we have determined critical exponents and amplitudes that have sometimes confirmed and other times challenged current theory. Recent experiments investigating the heat capacity and light scattering in a liquid-liquid mixture very close to the critical point will be discussed. This research is currently supported by The Petroleum Research Fund and by NASA grant NAG8-1433 with some student support from NSF-DMR 9619406.

  12. DNA hosted and aligned in aqueous interstitia of a lamellar liquid crystal – a membrane–biomacromolecule interaction model system

    KAUST Repository

    Carlsson, Nils

    2013-01-01

    We report that DNA molecules can be intercalated and macroscopically oriented in the aqueous interstitia of a lyotropic lamellar liquid crystal. Using UV-vis linear dichroism and fluorescence spectroscopy we show that double-stranded oligonucleotides (25 base pairs) in the water-octanoate-decanol system remain base-paired in the B conformation and are confined in two dimensions, with the helix axis preferentially parallel to the lipid bilayer surfaces but free to rotate within this plane. The degree of helix confinement and the corresponding 2-D orientation can be improved by decreasing the thickness of the water interstitia via the fraction of water in the ternary mixture. Not surprisingly, the corresponding single-stranded oligonucleotides are not aligned, with their persistence length being short in comparison to the lamellar interstitium thickness. We propose this as a model system for studying interactions of DNA-ligand complexes near a lipid bilayer membrane which we demonstrate by using dye probes that are either covalently attached to one end of the oligonucleotide or reversibly bound by intercalation between the base pairs. Three cationic dyes, all strongly bound by intercalation to DNA when free in solution, are found to not bind to DNA but to prefer the membrane surface. The covalently attached Cy5 also binds to the bilayer while Cy3 tends to end-stack to the oligonucleotide duplex. The orientation of Cy5 parallel to the membrane indicates that electrostatic surface binding predominates over insertion into the hydrophobic interior of the membrane. Anionic and zwitterionic dyes (FAM and ROX) are found to remain randomly oriented in the water between the lipid bilayer surfaces. © The Royal Society of Chemistry.

  13. Effects of confinement, surface-induced orientations and strain on dynamical behaviors of bacteria in thin liquid crystalline films.

    Science.gov (United States)

    Mushenheim, Peter C; Trivedi, Rishi R; Roy, Susmit Singha; Arnold, Michael S; Weibel, Douglas B; Abbott, Nicholas L

    2015-09-14

    We report on the organization and dynamics of bacteria (Proteus mirabilis) dispersed within lyotropic liquid crystal (LC) films confined by pairs of surfaces that induce homeotropic (perpendicular) or hybrid (homeotropic and parallel orientations at each surface) anchoring of the LC. By using motile vegetative bacteria (3 µm in length) and homeotropically aligned LC films with thicknesses that exceed the length of the rod-shaped cells, a key finding reported in this paper is that elastic torques generated by the LC are sufficiently large to overcome wall-induced hydrodynamic torques acting on the cells, thus leading to LC-guided bacterial motion near surfaces that orient LCs. This result extends to bacteria within LC films with hybrid anchoring, and leads to the observation that asymmetric strain within a hybrid aligned LC rectifies motions of motile cells. In contrast, when the LC film thickness is sufficiently small that confinement prevents alignment of the bacteria cells along a homeotropically aligned LC director (achieved using swarm cells of length 10-60 µm), the bacterial cells propel in directions orthogonal to the director, generating transient distortions in the LC that have striking "comet-like" optical signatures. In this limit, for hybrid LC films, we find LC elastic stresses deform the bodies of swarm cells into bent configurations that follow the LC director, thus unmasking a coupling between bacterial shape and LC strain. Overall, these results provide new insight into the influence of surface-oriented LCs on dynamical bacterial behaviors and hint at novel ways to manipulate bacteria using confined LC phases that are not possible in isotropic solutions.

  14. Solid on liquid deposition

    Energy Technology Data Exchange (ETDEWEB)

    Charmet, J., E-mail: jerome.charmet@he-arc.c [Institut des Microtechnologies Appliquees ARC, HES-SO Arc, Eplatures-Grise 17, 2300 La Chaux-de-Fonds (Switzerland); Banakh, O.; Laux, E.; Graf, B.; Dias, F.; Dunand, A.; Keppner, H. [Institut des Microtechnologies Appliquees ARC, HES-SO Arc, Eplatures-Grise 17, 2300 La Chaux-de-Fonds (Switzerland); Gorodyska, G.; Textor, M. [BioInterface group, ETHZ, Wolfgang-Pauli-Strasse 10, ETH Hoenggerberg HCI H 525 8093 Zuerich (Switzerland); Noell, W.; Rooij, N.F. de [Ecole Polytechnique Federale de Lausanne, Institute of Microengineering, Sensors, Actuators and Microsystems laboratory, Rue Jaquet Droz 1, 2000 Neuchatel (Switzerland); Neels, A.; Dadras, M.; Dommann, A.; Knapp, H. [Centre Suisse d' Electronique et de Microtechnique SA, Rue Jacquet-Droz 1, 2002 Neuchatel (Switzerland); Borter, Ch.; Benkhaira, M. [COMELEC SA, Rue de la Paix 129, 2300 La Chaux-de-Fonds (Switzerland)

    2010-07-01

    A process for the deposition of a solid layer onto a liquid is presented. The polymer poly-di-chloro-para-xylylene, also known as Parylene C, was grown on low vapour pressure liquids using the conventional low pressure chemical vapour deposition process. A reactor was built and a process developed to enable the deposition of Parylene C at atmospheric pressure over high vapour pressure liquids. It was used to deposit Parylene C over water among others. In all cases Parylene C encapsulated the liquid without influencing its initial shape. The results presented here show also that the Parylene C properties are not affected by its growth on liquid templates and the roughness of the Parylene C surface in contact with the liquid during the deposition is extremely low.

  15. Self-assembled multicompartment liquid crystalline lipid carriers for protein, peptide, and nucleic acid drug delivery.

    Science.gov (United States)

    Angelova, Angelina; Angelov, Borislav; Mutafchieva, Rada; Lesieur, Sylviane; Couvreur, Patrick

    2011-02-15

    Lipids and lipopolymers self-assembled into biocompatible nano- and mesostructured functional materials offer many potential applications in medicine and diagnostics. In this Account, we demonstrate how high-resolution structural investigations of bicontinuous cubic templates made from lyotropic thermosensitive liquid-crystalline (LC) materials have initiated the development of innovative lipidopolymeric self-assembled nanocarriers. Such structures have tunable nanochannel sizes, morphologies, and hierarchical inner organizations and provide potential vehicles for the predictable loading and release of therapeutic proteins, peptides, or nucleic acids. This Account shows that structural studies of swelling of bicontinuous cubic lipid/water phases are essential for overcoming the nanoscale constraints for encapsulation of large therapeutic molecules in multicompartment lipid carriers. For the systems described here, we have employed time-resolved small-angle X-ray scattering (SAXS) and high-resolution freeze-fracture electronic microscopy (FF-EM) to study the morphology and the dynamic topological transitions of these nanostructured multicomponent amphiphilic assemblies. Quasi-elastic light scattering and circular dichroism spectroscopy can provide additional information at the nanoscale about the behavior of lipid/protein self-assemblies under conditions that approximate physiological hydration. We wanted to generalize these findings to control the stability and the hydration of the water nanochannels in liquid-crystalline lipid nanovehicles and confine therapeutic biomolecules within these structures. Therefore we analyzed the influence of amphiphilic and soluble additives (e.g. poly(ethylene glycol)monooleate (MO-PEG), octyl glucoside (OG), proteins) on the nanochannels' size in a diamond (D)-type bicontinuous cubic phase of the lipid glycerol monooleate (MO). At body temperature, we can stabilize long-living swollen states, corresponding to a diamond cubic phase

  16. LIQUID CYCLONE CONTACTOR

    Science.gov (United States)

    Whatley, M.E.; Woods, W.M.

    1962-09-01

    This invention relates to liquid-liquid extraction systems. The invention, an improved hydroclone system, comprises a series of serially connected, axially aligned hydroclones, each of which is provided with an axially aligned overflow chamber. The chambers are so arranged that rotational motion of a fluid being passed through the system is not lost in passing from chamber to chamber; consequently, this system is highly efficient in contacting and separating two immiscible liquids. (AEC)

  17. ROMANIAN BANKS LIQUIDITY MANAGEMENT

    Directory of Open Access Journals (Sweden)

    BATRANCEA MARIA

    2013-07-01

    Full Text Available Most transactions or financial commitments have implications for a bank liquidity. Transactions are particularly vulnerable to liquidity problems at a specific institution. Therefore, one can deduce the importance of the correct calculation and liquidity indicator, not only for the bank concerned, but especially for NBR uses that bank risk management tool. That is why the authors took into consideration a sample of banks in Romania to show to what extent the banking crisis has influenced the development banks.

  18. Harvesting contaminants from liquid

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, John T.; Hunter, Scott R.

    2016-05-31

    Disclosed are examples of apparatuses for evaporative purification of a contaminated liquid. In each example, there is a vessel for storing the contaminated fluid. The vessel includes a surface coated with a layer of superhydrophobic material and the surface is at least partially in contact with the contaminated liquid. The contaminants do not adhere to the surface as the purified liquid evaporates, thus allowing the contaminants to be harvested.

  19. Parallel artificial liquid membrane extraction

    DEFF Research Database (Denmark)

    Gjelstad, Astrid; Rasmussen, Knut Einar; Parmer, Marthe Petrine

    2013-01-01

    This paper reports development of a new approach towards analytical liquid-liquid-liquid membrane extraction termed parallel artificial liquid membrane extraction. A donor plate and acceptor plate create a sandwich, in which each sample (human plasma) and acceptor solution is separated by an arti...... by an artificial liquid membrane. Parallel artificial liquid membrane extraction is a modification of hollow-fiber liquid-phase microextraction, where the hollow fibers are replaced by flat membranes in a 96-well plate format....

  20. Improved cross validation of a static ubiquitin structure derived from high precision residual dipolar couplings measured in a drug-based liquid crystalline phase.

    Science.gov (United States)

    Maltsev, Alexander S; Grishaev, Alexander; Roche, Julien; Zasloff, Michael; Bax, Ad

    2014-03-12

    The antibiotic squalamine forms a lyotropic liquid crystal at very low concentrations in water (0.3-3.5% w/v), which remains stable over a wide range of temperature (1-40 °C) and pH (4-8). Squalamine is positively charged, and comparison of the alignment of ubiquitin relative to 36 previously reported alignment conditions shows that it differs substantially from most of these, but is closest to liquid crystalline cetyl pyridinium bromide. High precision residual dipolar couplings (RDCs) measured for the backbone (1)H-(15)N, (15)N-(13)C', (1)H(α)-(13)C(α), and (13)C'-(13)C(α) one-bond interactions in the squalamine medium fit well to the static structural model previously derived from NMR data. Inclusion into the structure refinement procedure of these RDCs, together with (1)H-(15)N and (1)H(α)-(13)C(α) RDCs newly measured in Pf1, results in improved agreement between alignment-induced changes in (13)C' chemical shift, (3)JHNHα values, and (13)C(α)-(13)C(β) RDCs and corresponding values predicted by the structure, thereby validating the high quality of the single-conformer structural model. This result indicates that fitting of a single model to experimental data provides a better description of the average conformation than does averaging over previously reported NMR-derived ensemble representations. The latter can capture dynamic aspects of a protein, thus making the two representations valuable complements to one another.

  1. Remotely controllable liquid marbles

    KAUST Repository

    Zhang, Lianbin

    2012-07-26

    Liquid droplets encapsulated by self-organized hydrophobic particles at the liquid/air interface - liquid marbles - are prepared by encapsulating water droplets with novel core/shell-structured responsive magnetic particles, consisting of a responsive block copolymer-grafted mesoporous silica shell and magnetite core (see figure; P2VP-b-PDMS: poly(2-vinylpyridine-b- dimethylsiloxane)). Desirable properties of the liquid marbles include that they rupture upon ultraviolet illumination and can be remotely manipulated by an external magnetic field. 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Liquid hydrogen in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Yasumi, S. [Iwatani Corp., Osaka (Japan). Dept. of Overseas Business Development

    2009-07-01

    Japan's Iwatani Corporation has focused its attention on hydrogen as the ultimate energy source in future. Unlike the United States, hydrogen use and delivery in liquid form is extremely limited in the European Union and in Japan. Iwatani Corporation broke through industry stereotypes by creating and building Hydro Edge Co. Ltd., Japan's largest liquid hydrogen plant. It was established in 2006 as a joint venture between Iwatani and Kansai Electric Power Group in Osaka. Hydro Edge is Japan's first combined liquid hydrogen and ASU plant, and is fully operational. Liquid oxygen, liquid nitrogen and liquid argon are separated from air using the cryogenic energy of liquefied natural gas fuel that is used for power generation. Liquid hydrogen is produced efficiently and simultaneously using liquid nitrogen. Approximately 12 times as much hydrogen in liquid form can be transported and supplied as pressurized hydrogen gas. This technology is a significant step forward in the dissemination and expansion of hydrogen in a hydrogen-based economy.

  3. The Liquid Vapour Interface

    DEFF Research Database (Denmark)

    Als-Nielsen, Jens Aage

    1985-01-01

    In this short review we are concerned with the density variation across the liquid-vapour interface, i.e. from the bulk density of the liquid to the essentially zero density of the vapour phase. This density variation can in principle be determined from the deviation of the reflectivity from...

  4. LIGHT NONAQUEOUS PHASE LIQUIDS

    Science.gov (United States)

    Nonaqueous phase liquids (NAPLS) are hydrocarbons that exist as a separate, immiscible phase when in contact with water and/or air. ifferences in the physical and chemical properties of water and NAPL result in the formation of a physical interface between the liquids which preve...

  5. Disposal of Liquid Propellants

    Science.gov (United States)

    1990-03-13

    SYNTHESIS OF LIQUID PROPELLANT Hydroxylammonium nitrate (HAN), prepared via the electrolysis of nitric acid, is commercially available as a high-purity...stack gases, and brine solution from the wet scrubber (82). 5 Applicability/Limitation Most types of solid, liquid, and gaseous organic wastes or

  6. Liquid crystal colloids

    Directory of Open Access Journals (Sweden)

    2010-01-01

    Full Text Available This special issue of "Condensed Matter Physics" focuses on the most recent developments in the study of a fascinating soft matter system, representing colloidal particles in a liquid crystalline environment. Furthermore, some articles address pioneering steps in the discovery of liquid crystals going back to 1861 paper by Julius Planer.

  7. INEEL Liquid Effluent Inventory

    Energy Technology Data Exchange (ETDEWEB)

    Major, C.A.

    1997-06-01

    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.

  8. The TIPS Liquidity Premium

    DEFF Research Database (Denmark)

    Andreasen, Martin Møller; Christensen, Jens H.E.; Simon Riddell, Simon

    We introduce an arbitrage-free term structure model of nominal and real yields that accounts for liquidity risk in Treasury inflation-protected securities (TIPS). The novel feature of our model is to identify liquidity risk from individual TIPS prices by accounting for the tendency that TIPS, lik...

  9. Air/liquid collectors

    DEFF Research Database (Denmark)

    Jensen, Søren Østergaard; Olesen, Ole; Kristiansen, Finn Harken

    1997-01-01

    This report determine efficiency equations for combined air/liquid solar collectors by measurements on to different air/liquid collectors. Equations which contain all relevant informations on the solar collectors. A simulation program (Kviksol) has been modified in order to be able to handle...

  10. Liquid heat capacity lasers

    Science.gov (United States)

    Comaskey, Brian J.; Scheibner, Karl F.; Ault, Earl R.

    2007-05-01

    The heat capacity laser concept is extended to systems in which the heat capacity lasing media is a liquid. The laser active liquid is circulated from a reservoir (where the bulk of the media and hence waste heat resides) through a channel so configured for both optical pumping of the media for gain and for light amplification from the resulting gain.

  11. Liquid Chromatography in 1982.

    Science.gov (United States)

    Freeman, David H.

    1982-01-01

    Reviews trends in liquid chromatography including apparatus, factors affecting efficient separation of a mixture (peak sharpness and speed), simplified problem-solving, adsorption, bonded phase chromatography, ion selectivity, and size exclusion. The current trend is to control chemical selectivity by the liquid phase. (Author/JN)

  12. Column Liquid Chromatography.

    Science.gov (United States)

    Majors, Ronald E.; And Others

    1984-01-01

    Reviews literature covering developments of column liquid chromatography during 1982-83. Areas considered include: books and reviews; general theory; columns; instrumentation; detectors; automation and data handling; multidimensional chromatographic and column switching techniques; liquid-solid chromatography; normal bonded-phase, reversed-phase,…

  13. Modeling of ionic liquids

    Science.gov (United States)

    Tatlipinar, Hasan

    2017-02-01

    Ionic liquids are very important entry to industry and technology. Because of their unique properties they may classified as a new class of materials. IL usually classified as a high temperature ionic liquids (HTIL) and room temperature ionic liquids (RTIL). HTIL are molten salts. There are many research studies on molten salts such as recycling, new energy sources, rare elements mining. RTIL recently become very important in daily life industry because of their "green chemistry" properties. As a simple view ionic liquids consist of one positively charged and one negatively charged components. Because of their Coulombic or dispersive interactions the local structure of ionic liquids emerges. In this presentation the local structural properties of the HTIL are discussed via correlation functions and integral equation theories. RTIL are much more difficult to do modeling, but still general consideration for the modeling of the HTIL is valid also for the RTIL.

  14. Liquid-liquid phase transition in Stillinger-Weber silicon

    Energy Technology Data Exchange (ETDEWEB)

    Beaucage, Philippe; Mousseau, Normand [Departement de Physique and Regroupement Quebecois sur les Materiaux de Pointe, Universite de Montreal, CP 6128, Succursale Centre-ville, Montreal, QC, H3C 3J7 (Canada)

    2005-04-20

    It was recently demonstrated that Stillinger-Weber silicon undergoes a liquid-liquid first-order phase transition deep into the supercooled region (Sastry and Angell 2003 Nat. Mater. 2 739). Here we study the effects of perturbations on this phase transition. We show that the order of the liquid-liquid transition changes with negative pressure. We also find that the liquid-liquid transition disappears when the three-body term of the potential is strengthened by as little as 5%. This implies that the details of the potential could affect strongly the nature and even the existence of the liquid-liquid phase.

  15. Antitumor Agents 286. Design, Synthesis and Structure-Activity Relationships of 3′R,4′R-Disubstituted-2′,2′-dimethyldihydropyrano[2,3-f]chromone (DSP) Analogs as Potent Chemosensitizers to Overcome Multidrug Resistance

    Science.gov (United States)

    Zhou, Ting; Shi, Qian; Bastow, Kenneth F.; Lee, Kuo-Hsiung

    2010-01-01

    In this study, various 3′R,4′R-disubstituted-2′,2′-dimethydihydropyrano[2,3-f]chromone (DSP) derivatives were discovered as potent chemosensitizers in the treatment of multidrug resistant cancer cells. Twenty-four DSP analogs (5–28) were synthesized and evaluated against a multi-drug resistant (MDR) cell line (KB-Vin) with and without vincristine (VCR). All DSP analogs exhibited low intrinsic cytotoxicity. However, in combination treatment, most DSPs reversed resistance to VCR and lowered the GI50 value of VCR by 12–349-fold. At a concentration of 1μg/mL, three compounds, 11, 14 and 21, fully reversed resistance to VCR in KB-Vin cancer cells, a twofold increase compared to verapamil, a first generation chemosensitizer. Detailed structure-activity relationship (SAR) conclusions were established based on 3′ and 4′ substitutions. Moreover, a preliminary mechanism study indicated that the chemosensitizing activity of DSP analogs results from inhibition of P-glycoprotein (P-gp) over-expressed in MDR cancer cells.1 PMID:21082774

  16. The Risk Components of Liquidity

    OpenAIRE

    Chollete, Lorán; Næs, Randi; Johannes A. Skjeltorp

    2008-01-01

    Does liquidity risk differ depending on our choice of liquidity proxy? Unlike literature that considers common liquidity variation, we focus on identifying different components of liquidity, statistically and economically, using more than a decade of US transaction data. We identify three main statistical liquidity factors which are utilized in a linear asset pricing framework. We motivate a correspondence of the statistical factors to traditional dimensions of liquidity as well as the notion...

  17. Liquid metal enabled microfluidics.

    Science.gov (United States)

    Khoshmanesh, Khashayar; Tang, Shi-Yang; Zhu, Jiu Yang; Schaefer, Samira; Mitchell, Arnan; Kalantar-Zadeh, Kourosh; Dickey, Michael D

    2017-03-14

    Several gallium-based liquid metal alloys are liquid at room temperature. As 'liquid', such alloys have a low viscosity and a high surface tension while as 'metal', they have high thermal and electrical conductivities, similar to mercury. However, unlike mercury, these liquid metal alloys have low toxicity and a negligible vapor pressure, rendering them much safer. In comparison to mercury, the distinguishing feature of these alloys is the rapid formation of a self-limiting atomically thin layer of gallium oxide over their surface when exposed to oxygen. This oxide layer changes many physical and chemical properties of gallium alloys, including their interfacial and rheological properties, which can be employed and modulated for various applications in microfluidics. Injecting liquid metal into microfluidic structures has been extensively used to pattern and encapsulate highly deformable and reconfigurable electronic devices including electrodes, sensors, antennas, and interconnects. Likewise, the unique features of liquid metals have been employed for fabricating miniaturized microfluidic components including pumps, valves, heaters, and electrodes. In this review, we discuss liquid metal enabled microfluidic components, and highlight their desirable attributes including simple fabrication, facile integration, stretchability, reconfigurability, and low power consumption, with promising applications for highly integrated microfluidic systems.

  18. Spreading of miscible liquids

    Science.gov (United States)

    Walls, Daniel J.; Haward, Simon J.; Shen, Amy Q.; Fuller, Gerald G.

    2016-05-01

    Miscible liquids commonly contact one another in natural and technological situations, often in the proximity of a solid substrate. In the scenario where a drop of one liquid finds itself on a solid surface and immersed within a second, miscible liquid, it will spread spontaneously across the surface. We show experimental findings of the spreading of sessile drops in miscible environments that have distinctly different shape evolution and power-law dynamics from sessile drops that spread in immiscible environments, which have been reported previously. We develop a characteristic time to scale radial data of the spreading sessile drops based on a drainage flow due to gravity. This time scale is effective for a homologous subset of the liquids studied. However, it has limitations when applied to significantly chemically different, yet miscible, liquid pairings; we postulate that the surface energies between each liquid and the solid surface becomes important for this other subset of the liquids studied. Initial experiments performed with pendant drops in miscible environments support the drainage flow observed in the sessile drop systems.

  19. Liquid crystals fundamentals

    CERN Document Server

    Singh, Shri

    2001-01-01

    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

  20. Ionic and Molecular Liquids

    DEFF Research Database (Denmark)

    Chaban, Vitaly V.; Prezhdo, Oleg

    2013-01-01

    Because of their outstanding versatility, room-temperature ionic liquids (RTILs) are utilized in an ever increasing number of novel and fascinating applications, making them the Holy Grail of modern materials science. In this Perspective, we address the fundamental research and prospective...... applications of RTILs in combination with molecular liquids, concentrating on three significant areas: (1) the use of molecular liquids to decrease the viscosity of RTILs; (2) the role of RTIL micelle formation in water and organic solvents; and (3) the ability of RTILs to adsorb pollutant gases. Current...

  1. Liquidity and Risk Management

    OpenAIRE

    Holmström, Bengt; Tirole, Jean

    2007-01-01

    This paper provides a model of the interaction between risk-management practices and market liquidity. On one hand, tighter risk management reduces the maximum position an institution can take, thus the amount of liquidity it can offer to the market. On the other hand, risk managers can take into account that lower liquidity amplifies the effective risk of a position by lengthening the time it takes to sell it. The main result of the paper is that a feedback effect can arise: tighter risk man...

  2. Transient Grating Investigations at Liquid-Liquid Interfaces

    OpenAIRE

    Punzi, Angela; Brodard, Pierre; Vauthey, Eric

    2005-01-01

    A new four-wave-mixing technique with evanescent optical fields generated by total internal reflection at a liquid-liquid interface is described. Several applications of this method to measure thermoacoustic and dynamic properties near liquid-liquid interfaces are presented.

  3. Chiral separation by enantioselective liquid-liquid extraction

    NARCIS (Netherlands)

    Schuur, B.; Verkuijl, B. J. V.; Minnaard, A. J.; De Vries, J. G.; Heeres, H. J.; Feringa, B. L.

    2011-01-01

    The literature on enantioselective liquid-liquid extraction (ELLE) spans more than half a century of research. Nonetheless, a comprehensive overview has not appeared during the past few decades. Enantioselective liquid-liquid extraction is a technology of interest for a wide range of chemists and ch

  4. Liquid-Liquid Hydrocyclone Adopted in Jilin Oil Fields

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    @@ As a new invention with high technique, liquid-liquid hydrocyclone (LLH) was developed in the world in the 1980s. It is designed to separate mutually insoluble liquid mixtures by its geometry and structure which cause an eddy motion in the internal of the liquid. It is characterized by the absence of moving parts in itself.

  5. Beyond dispersive liquid-liquid microextraction.

    Science.gov (United States)

    Leong, Mei-I; Fuh, Ming-Ren; Huang, Shang-Da

    2014-03-28

    Dispersive liquid-liquid microextraction (DLLME) and other dispersion liquid-phase microextraction (LPME) methods have been developed since the first DLLME method was reported in 2006. DLLME is simple, rapid, and affords high enrichment factor, this is due to the large contact surface area of the extraction solvent. DLLME is a method suitable for the extraction in many different water samples, but it requires using chlorinated solvents. In recent years, interest in DLLME or dispersion LPME has been focused on the use of low-toxicity solvents and more conveniently practical procedures. This review examines some of the most interesting developments in the past few years. In the first section, DLLME methods are separated in two categories: DLLME with low-density extraction solvent and DLLME with high-density extraction solvent. Besides these methods, many novel special devices for collecting low-density extraction solvent are also mentioned. In addition, various dispersion techniques with LPME, including manual shaking, air-assisted LPME (aspirating and injecting the extraction mixture by syringe), ultrasound-assisted emulsification, vortex-assisted emulsification, surfactant-assisted emulsification, and microwave-assisted emulsification are described. Besides the above methods, combinations of DLLME with other extraction techniques (solid-phase extraction, stir bar sorptive extraction, molecularly imprinted matrix solid-phase dispersion and supercritical fluid extraction) are introduced. The combination of nanotechnique with DLLME is also introduced. Furthermore, this review illustrates the application of DLLME or dispersion LPME methods to separate and preconcentrate various organic analytes, inorganic analytes, and samples.

  6. Fermi liquid theory

    CERN Document Server

    Apostol, M

    2001-01-01

    sup 3 He liquefies at 3.2 K under normal pressure, where its mean inter-particle separation of a few angstroms, is comparable with the range of the interaction potential (and with the mean inter-particle separation in the corresponding ideal gas); its thermal wavelength is about 8 A, so that, under this conditions, sup 3 He is a quantum liquid of fermions, or a Fermi liquid (sometimes called a normal Fermi liquid too). The motion of the sup 3 He atoms in the (repulsive) self-consistent, meanfield potential is affected by inertial effects, i.e. the particles possess an effective mass, and consequently they obey the Fermi distribution, like an ideal Fermi gas. In this paper the Landau's theory of the Fermi liquid is reviewed. (author)

  7. Corporate governance and liquidity

    DEFF Research Database (Denmark)

    Farooq, Omar; Derrabi, Mohamed; Naciri, Monir

    2012-01-01

    This paper examines the impact of corporate governance mechanisms on liquidity in the MENA region, i.e. Morocco, Egypt, Saudi Arabia, United Arab Emirates, Jordan, Kuwait, and Bahrain. Using turnover as a proxy for liquidity, we document significant difference in liquidity between the pre......- and the post-crisis periods in the MENA region. In addition, our results show that bulk of this reduction in turnover can be explained due to weaknesses of corporate governance mechanisms. For example, that dividend payout ratio and choice of auditors – proxies for agency problems – can explain the entire...... difference in liquidity between the two periods. Furthermore, our results indicate that more than 50% of this difference between the two periods can be explained by operational and informational complexity of a firm – proxy for transparency. We argue that poor corporate governance mechanisms increase...

  8. Liquid-Cooled Garment

    Science.gov (United States)

    1977-01-01

    A liquid-cooled bra, offshoot of Apollo moon suit technology, aids the cancer-detection technique known as infrared thermography. Water flowing through tubes in the bra cools the skin surface to improve resolution of thermograph image.

  9. Wettability by Ionic Liquids.

    Science.gov (United States)

    Liu, Hongliang; Jiang, Lei

    2016-01-06

    Ionic liquids (ILs) have become particularly attractive recently because they have demonstrated themselves to be important construction units in the broad fields of chemistry and materials science, from catalysis and synthesis to analysis and electrochemistry, from functional fluids to clean energy, from nanotechnology to functional materials. One of the greatest issues that determines the performance of ILs is the wettability of correlated surfaces. In this concept article, the key developments and issues in IL wettability are surveyed, including the electrowetting of ILs in gas-liquid-solid systems and liquid-liquid-solid systems, ILs as useful probe fluids, the superwettability of Ils, and future directions in IL wettability. This should generate extensive interest in the field and encourage more scientists to engage in this area to tackle its scientific challenges.

  10. Liquid rocket engine injectors

    Science.gov (United States)

    Gill, G. S.; Nurick, W. H.

    1976-01-01

    The injector in a liquid rocket engine atomizes and mixes the fuel with the oxidizer to produce efficient and stable combustion that will provide the required thrust without endangering hardware durability. Injectors usually take the form of a perforated disk at the head of the rocket engine combustion chamber, and have varied from a few inches to more than a yard in diameter. This monograph treats specifically bipropellant injectors, emphasis being placed on the liquid/liquid and liquid/gas injectors that have been developed for and used in flight-proven engines. The information provided has limited application to monopropellant injectors and gas/gas propellant systems. Critical problems that may arise during injector development and the approaches that lead to successful design are discussed.

  11. Lacerations - liquid bandage

    Science.gov (United States)

    ... be found at your local pharmacy. Applying and Caring for a Liquid Bandage With clean hands or ... Bethesda, MD 20894 U.S. Department of Health and Human Services National Institutes of Health Page last updated: ...

  12. Ionic liquids in tribology.

    Science.gov (United States)

    Minami, Ichiro

    2009-06-24

    Current research on room-temperature ionic liquids as lubricants is described. Ionic liquids possess excellent properties such as non-volatility, non-flammability, and thermo-oxidative stability. The potential use of ionic liquids as lubricants was first proposed in 2001 and approximately 70 articles pertaining to fundamental research on ionic liquids have been published through May 2009. A large majority of the cations examined in this area are derived from 1,3-dialkylimidazolium, with a higher alkyl group on the imidazolium cation being beneficial for good lubrication, while it reduces the thermo-oxidative stability. Hydrophobic anions provide both good lubricity and significant thermo-oxidative stability. The anions decompose through a tribochemical reaction to generate metal fluoride on the rubbed surface. Additive technology to improve lubricity is also explained. An introduction to tribology as an interdisciplinary field of lubrication is also provided.

  13. Ionic Liquids in Tribology

    Directory of Open Access Journals (Sweden)

    Ichiro Minami

    2009-06-01

    Full Text Available Current research on room-temperature ionic liquids as lubricants is described. Ionic liquids possess excellent properties such as non-volatility, non-flammability, and thermo-oxidative stability. The potential use of ionic liquids as lubricants was first proposed in 2001 and approximately 70 articles pertaining to fundamental research on ionic liquids have been published through May 2009. A large majority of the cations examined in this area are derived from 1,3-dialkylimidazolium, with a higher alkyl group on the imidazolium cation being beneficial for good lubrication, while it reduces the thermo-oxidative stability. Hydrophobic anions provide both good lubricity and significant thermo-oxidative stability. The anions decompose through a tribochemical reaction to generate metal fluoride on the rubbed surface. Additive technology to improve lubricity is also explained. An introduction to tribology as an interdisciplinary field of lubrication is also provided.

  14. Corporate governance and liquidity

    DEFF Research Database (Denmark)

    Farooq, Omar; Derrabi, Mohamed; Naciri, Monir

    2012-01-01

    This paper examines the impact of corporate governance mechanisms on liquidity in the MENA region, i.e. Morocco, Egypt, Saudi Arabia, United Arab Emirates, Jordan, Kuwait, and Bahrain. Using turnover as a proxy for liquidity, we document significant difference in liquidity between the pre......- and the post-crisis periods in the MENA region. In addition, our results show that bulk of this reduction in turnover can be explained due to weaknesses of corporate governance mechanisms. For example, that dividend payout ratio and choice of auditors – proxies for agency problems – can explain the entire...... difference in liquidity between the two periods. Furthermore, our results indicate that more than 50% of this difference between the two periods can be explained by operational and informational complexity of a firm – proxy for transparency. We argue that poor corporate governance mechanisms increase...

  15. Gases, liquids and solids

    CERN Document Server

    Tabor, David

    1969-01-01

    It has been tradional to treat gases, liquids and solids as if they were completely unrelated material. However, this book shows that many of their bulk properties can been explained in terms of intermolecular forces.

  16. Liquid Crystal Airborne Display

    Science.gov (United States)

    1977-08-01

    81/2X 11- 10 -9 .8 display using a large advertising alphanimeric ( TCI ) has been added to the front of the optical box used in the F-4 aircraft for HUD...properties over a wide range of tempera - tures, including normal room temperature. What are Liquid Crystals? Liquid crystals have been classified in three...natic fanctions and to present data needed for the semi- automatic and manual control of system functions. Existing aircraft using CRT display

  17. COMMERCIAL BANK LIQUIDITY MANAGEMENT

    OpenAIRE

    KOREKOV A.V.

    2015-01-01

    Bank liquidity management and optimal resource allocation of commercial bank Nostro accounts balances receive much less attention from the scientists compared to the questions on capital structure, funding, credit risk analysis and stress testing. Optimal liquidity management is a way to lower bank costs and risks, which are going to increase over time, especially when money markets are dry of free funds. There are two sides of the issue to be analyzed. The optimal resource allocation and cor...

  18. Gas to liquids

    Energy Technology Data Exchange (ETDEWEB)

    Roche, Pat

    2011-04-15

    Sasol, a South African company, along with the Canadian company Talisman, are looking at gas to liquid process opportunities in North America. Sasol decided to launch a study into the feasibility of gas to liquid (GTL) operation in western Canada, and according to previous studies GTL would need a crude barrel price of $85 or higher combined with a gas price of $4 or less to be economical. Sasol is already operating a GTL plant in Qatar.

  19. The reversibility and first-order nature of liquid-liquid transition in a molecular liquid

    Science.gov (United States)

    Kobayashi, Mika; Tanaka, Hajime

    2016-11-01

    Liquid-liquid transition is an intriguing phenomenon in which a liquid transforms into another liquid via the first-order transition. For molecular liquids, however, it always takes place in a supercooled liquid state metastable against crystallization, which has led to a number of serious debates concerning its origin: liquid-liquid transition versus unusual nano-crystal formation. Thus, there have so far been no single example free from such debates, to the best of our knowledge. Here we show experimental evidence that the transition is truly liquid-liquid transition and not nano-crystallization for a molecular liquid, triphenyl phosphite. We kinetically isolate the reverse liquid-liquid transition from glass transition and crystallization with a high heating rate of flash differential scanning calorimetry, and prove the reversibility and first-order nature of liquid-liquid transition. Our finding not only deepens our physical understanding of liquid-liquid transition but may also initiate a phase of its research from both fundamental and applications viewpoints.

  20. Supercooled liquids for pedestrians

    Science.gov (United States)

    Cavagna, Andrea

    2009-06-01

    When we lower the temperature of a liquid, at some point we meet a first order phase transition to the crystal. Yet, under certain conditions it is possible to keep the system in its metastable phase and to avoid crystallization. In this way the liquid enters in the supercooled phase. Supercooled liquids have a very rich phenomenology, which is still far from being completely understood. To begin with, there is the problem of how to prevent crystallization and how deeply the liquid can be supercooled before a metastability limit is hit. But by far the most interesting feature of supercooled liquids is the dynamic glass transition: when the temperature is decreased below a certain point, the relaxation time increases so much that a dramatic dynamical arrest intervenes and we are unable to equilibrate the system within reasonable experimental times. The glass transition is a phenomenon whose physical origin has stirred an enormous interest in the last hundred years. Why does it occur? Is it just a conventional reference point, or does it have a more profound physical meaning? Is it a purely dynamical event, or the manifestation of a true thermodynamic transition? What is the correlation length associated to the sharp increase of the relaxation time? Can we define a new kind of amorphous order? A shared theory of supercooled liquids and the glass transition does not yet exist and these questions are still largely open. Here, I will illustrate in the most elementary fashion the main phenomenological traits of supercooled liquids and discuss in a very partial way a few theoretical ideas on the subject.

  1. Liquidity Risk and Syndicate Structure

    OpenAIRE

    Evan Gatev; Philip Strahan

    2008-01-01

    We offer a new explanation of loan syndicate structure based on banks' comparative advantage in managing systematic liquidity risk. When a syndicated loan to a rated borrower has systematic liquidity risk, the fraction of passive participant lenders that are banks is about 8% higher than for loans without liquidity risk. In contrast, liquidity risk does not explain the share of banks as lead lenders. Using a new measure of ex-ante liquidity risk exposure, we find further evidence that syndica...

  2. On the identification of liquid surface properties using liquid bridges.

    Science.gov (United States)

    Kostoglou, M; Karapantsios, T D

    2015-08-01

    The term liquid bridge refers to the specific silhouette of a liquid volume when it is placed between two solid surfaces. Liquid bridges have been studied extensively both theoretically and experimentally during the last century due to their significance in many technological applications. It is worth noticing that even today new technological applications based on liquid bridges continue to appear. A liquid bridge has a well-defined surface configuration dictated by a rigid theoretical foundation so the potential of its utilization as a tool to study surface properties of liquids is apparent. However, it is very scarce in literature that the use of liquid bridges is suggested as an alternative to the well-established drop techniques (pendant/sessile drop). The present work (i) presents the theoretical background for setting up a liquid-bridge based surface property estimation problem, (ii) describes the required experimental equipment and procedures and (iii) performs a thorough literature review on the subject. A case with particular interest is that of liquid bridges made of electrically conducting liquids forming between two conducting solids; such a liquid bridge presents an integral electrical conductance value which is sensitive to the specific silhouette of the bridge. This enables the use of this integral conductance as shape descriptor instead of the conventional image processing techniques. Several attempts in literature for the estimation of liquid surface tension, liquid-solid contact angle and surfactant induced surface elasticity for conducting or non/conducting liquids are presented and the prospects of the technique are discussed.

  3. Redox chemistry at liquid/liquid interfaces

    Science.gov (United States)

    Volkov, A. G.; Deamer, D. W.

    1997-01-01

    The interface between two immiscible liquids with immobilized photosynthetic pigments can serve as the simplest model of a biological membrane convenient for the investigation of photoprocesses accompanied by spatial separation of charges. As it follows from thermodynamics, if the resolvation energies of substrates and products are very different, the interface between two immiscible liquids may act as a catalyst. Theoretical aspects of charge transfer reactions at oil/water interfaces are discussed. Conditions under which the free energy of activation of the interfacial reaction of electron transfer decreases are established. The activation energy of electron transfer depends on the charges of the reactants and dielectric permittivity of the non-aqueous phase. This can be useful when choosing a pair of immiscible solvents to decrease the activation energy of the reaction in question or to inhibit an undesired process. Experimental interfacial catalytic systems are discussed. Amphiphilic molecules such as chlorophyll or porphyrins were studied as catalysts of electron transfer reactions at the oil/water interface.

  4. Laser imaging in liquid-liquid flows

    Science.gov (United States)

    Abidin, M. I. I. Zainal; Park, Kyeong H.; Voulgaropoulos, Victor; Chinaud, Maxime; Angeli, Panagiota

    2016-11-01

    In this work, the flow patterns formed during the horizontal flow of two immiscible liquids are studied. The pipe is made from acrylic, has an ID of 26 mm and a length of 4 m. A silicone oil (5cSt) and a water/glycerol mixture are used as test fluids. This set of liquids is chosen to match the refractive indices of the phases and enable laser based flow pattern identification. A double pulsed Nd:Yag laser was employed (532mm) with the appropriate optics to generate a laser sheet at the middle of the pipe. The aqueous phase was dyed with Rhodamine 6G, to distinguish between the two phases. Experiments were carried out for mixture velocities ranging from 0.15 to 2 m/s. Different inlet designs were used to actuate flow patterns in a controlled way and observe their development downstream the test section. A static mixer produced dispersed flow at the inlet which separated downstream due to enhanced coalescence. On the other hand, the use of a cylindrical bluff body at the inlet created non-linear interfacial waves in initially stratified flows from which drops detached leading to the transition to dispersed patterns. From the detailed images important flow parameters were measured such as wave characteristics and drop size. Project funded under the UK Engineering and Physical Sciences Research Council (EPSRC) Programme Grant MEMPHIS.

  5. Macromolecular sensing at the liquid-liquid interface

    Energy Technology Data Exchange (ETDEWEB)

    Herzog, Gregoire; Flynn, Shane [Tyndall National Institute, Lee Maltings, University College, Cork (Ireland); Arrigan, Damien W M, E-mail: gregoire.herzog@tyndall.ie [Nanochemistry Research Institute, Department of Chemistry, Curtin University, Perth (Australia)

    2011-08-17

    We report here the electrochemical sensing of macromolecules, such as polyLysine dendrimers, at the polarised liquid | liquid interface. Electrochemistry at the liquid | liquid interface is a powerful analytical technique which allows the detection of non-redox active molecules via ion transfer reactions at a polarised water - oil interface. We demonstrate here that different parameters of the polyLysine dendrimers (charge number, molecular weight) have a strong influence on the sensitivity and limit of detection of these macromolecules. This work will help to the development of sensors based on charge transfer at the liquid | liquid interface.

  6. Liquid lubrication in space

    Science.gov (United States)

    Zaretsky, Erwin V.

    1990-01-01

    The requirement for long-term, reliable operation of aerospace mechanisms has, with a few exceptions, pushed the state of the art in tribology. Space mission life requirements in the early 1960s were generally 6 months to a year. The proposed U.S. space station schedule to be launched in the 1990s must be continuously usable for 10 to 20 years. Liquid lubrication systems are generally used for mission life requirements longer than a year. Although most spacecraft or satellites have reached their required lifetimes without a lubrication-related failure, the application of liquid lubricants in the space environment presents unique challenges. The state of the art of liquid lubrication in space as well as the problems and their solutions are reviewed.

  7. Liquid crystals in tribology.

    Science.gov (United States)

    Carrión, Francisco-José; Martínez-Nicolás, Ginés; Iglesias, Patricia; Sanes, José; Bermúdez, María-Dolores

    2009-09-18

    Two decades ago, the literature dealing with the possible applications of low molar mass liquid crystals, also called monomer liquid crystals (MLCs), only included about 50 references. Today, thousands of papers, conference reports, books or book chapters and patents refer to the study and applications of MLCs as lubricants and lubricant additives and efforts are made to develop new commercial applications. The development of more efficient lubricants is of paramount technological and economic relevance as it is estimated that half the energy consumption is dissipated as friction. MLCs have shown their ability to form ordered boundary layers with good load-carrying capacity and to lower the friction coefficients, wear rates and contact temperature of sliding surfaces, thus contributing to increase the components service life and to save energy. This review includes the use of MLCs in lubrication, and dispersions of MLCs in conventional polymers (PDMLCs). Finally, new lubricating system composed of MLC blends with surfactants, ionic liquids or nanophases are considered.

  8. Neutron scattering in liquids

    Energy Technology Data Exchange (ETDEWEB)

    Barocchi, F. [Florence Univ. (Italy). Ist. di Fisica

    1996-12-31

    Together with X-rays, thermal neutrons are the ideal probe to study the microscopic structure of condensed matter, however the precision attainable usually with neutrons for the measurement of atomic position correlation functions in liquids is, at least, one order of magnitude better than for X-rays. In order to measure properly the microscopic dynamics a wide range of momentum transfer with corresponding energy transfer must be available in the range of liquid state excitations. This again is only attainable, with good resolution, with neutrons. (author) 7 figs., 3 refs.

  9. Bicontinuous liquid crystals

    CERN Document Server

    Lynch, Mathew L

    2005-01-01

    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. Air/liquid collectors

    DEFF Research Database (Denmark)

    Jensen, Søren Østergaard; Olesen, Ole; Kristiansen, Finn Harken

    1997-01-01

    This report determine efficiency equations for combined air/liquid solar collectors by measurements on to different air/liquid collectors. Equations which contain all relevant informations on the solar collectors. A simulation program (Kviksol) has been modified in order to be able to handle...... this kind of collectors. The modified simulation program has been used for the determination of the surplus in performance which solar heating systems with this type of solar collectors for combined preheating of ventilation air and domestic hot water will have. The simulation program and the efficiency...

  11. Modeling of liquid phases

    CERN Document Server

    Soustelle, Michel

    2015-01-01

    This book is part of a set of books which offers advanced students successive characterization tool phases, the study of all types of phase (liquid, gas and solid, pure or multi-component), process engineering, chemical and electrochemical equilibria, and the properties of surfaces and phases of small sizes. Macroscopic and microscopic models are in turn covered with a constant correlation between the two scales. Particular attention has been given to the rigor of mathematical developments. This second volume in the set is devoted to the study of liquid phases.

  12. Theory of simple liquids

    CERN Document Server

    Hansen, Jean-Pierre

    1986-01-01

    This book gives a comprehensive and up-to-date treatment of the theory of ""simple"" liquids. The new second edition has been rearranged and considerably expanded to give a balanced account both of basic theory and of the advances of the past decade. It presents the main ideas of modern liquid state theory in a way that is both pedagogical and self-contained. The book should be accessible to graduate students and research workers, both experimentalists and theorists, who have a good background in elementary mechanics.Key Features* Compares theoretical deductions with experimental r

  13. High Birefringence Liquid Crystals

    Directory of Open Access Journals (Sweden)

    Jakub Herman

    2013-09-01

    Full Text Available Liquid crystals, compounds and mixtures with positive dielectric anisotropies are reviewed. The mesogenic properties and physical chemical properties (viscosity, birefringence, refractive indices, dielectric anisotropy and elastic constants of compounds being cyano, fluoro, isothiocyanato derivatives of biphenyl, terphenyl, quaterphenyl, tolane, phenyl tolane, phenyl ethynyl tolane, and biphenyl tolane are compared. The question of how to obtain liquid crystal with a broad range of nematic phases is discussed in detail. Influence of lateral substituent of different kinds of mesogenic and physicochemical properties is presented (demonstrated. Examples of mixtures with birefringence ∆n in the range of 0.2–0.5 are given.

  14. Molecular structure, spectral investigation (1H NMR, 13C NMR, UV-Visible, FT-IR, FT-Raman), NBO, intramolecular hydrogen bonding, chemical reactivity and first hyperpolarizability analysis of formononetin [7-hydroxy-3(4-methoxyphenyl)chromone]: A quantum chemical study

    Science.gov (United States)

    Srivastava, Anubha; Mishra, Rashmi; Kumar, Sudhir; Dev, Kapil; Tandon, Poonam; Maurya, Rakesh

    2015-03-01

    Formononetin [7-hydroxy-3(4-methoxyphenyl)chromone or 4‧-methoxy daidzein] is a soy isoflavonoid that is found abundantly in traditional Chinese medicine Astragalus mongholicus (Bunge) and Trifolium pretense L. (red clover), and in an Indian medicinal plant, Butea (B.) monosperma. Crude extract of B.monosperma is used for rapid healing of fracture in Indian traditional medicine. In this study, a combined theoretical and experimental approach is used to study the properties of formononetin. The optimized geometry was calculated by B3LYP method using 6-311++G(d,p) as a large basis set. The FT-Raman and FT-IR spectra were recorded in the solid phase, and interpreted in terms of potential energy distribution (PED) analysis. Density functional theory (DFT) is applied to explore the nonlinear optical properties of the molecule. Good consistency is found between the calculated results and observed data for the electronic absorption, IR and Raman spectra. The solvent effects have been calculated using time-dependent density functional theory in combination with the integral equation formalism polarized continuum model, and the results are in good agreement with observed measurements. The double well potential energy curve of the molecule about the respective bonds, have been plotted, as obtained from DFT/6-31G basis set. The computational results diagnose the most stable conformer of formononetin. The HOMO-LUMO energy gap of possible conformers has been calculated for comparing their chemical activity. Chemical reactivity has been measured by reactivity descriptors and molecular electrostatic potential surface (MEP). The 1H and 13C NMR chemical shifts of the molecule were calculated by the Gauge including atomic orbital (GIAO) method. Furthermore, the role of CHsbnd O intramolecular hydrogen bond in the stability of molecule is investigated on the basis of the results of topological properties of AIM theory and NBO analysis. The calculated first hyperpolarizability shows

  15. Liquid crystalline order in polymers

    CERN Document Server

    Blumstein, Alexandre

    1978-01-01

    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

  16. Study on mechanism and preparation technology of the lyotropic liquid crystal template for separating and purifying fat-soluble carotenoids from Tagetes patula L.%制备溶致液晶模板分离纯化孔雀草脂溶性类胡萝卜素技术及其机理初探

    Institute of Scientific and Technical Information of China (English)

    张瑞; 敬思群; 吉恒莹; 张永军; 邢军

    2009-01-01

    制备溶致液晶模板对天然色素分子进行分离纯化是一种高收率、低成本、操作安全、适于天然色素工业化生产的新型分离纯化技术.本文论述了通过制备孔雀草脂溶性类胡萝卜素溶致液晶模板,分离纯化该色素的技术方法,同时还分析并提出了制备溶致液晶模板对天然色素分子进行分离纯化的机理假设-化学反应模板理论.

  17. Mixed Stationary Liquid Phases for Gas-Liquid Chromatography.

    Science.gov (United States)

    Koury, Albert M.; Parcher, Jon F.

    1979-01-01

    Describes a laboratory technique for use in an undergraduate instrumental analysis course that, using the interpretation of window diagrams, prepares a mixed liquid phase column for gas-liquid chromatography. A detailed procedure is provided. (BT)

  18. Properties of Liquid Plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Freibert, Franz J. [Los Alamos National Laboratory; Mitchell, Jeremy N. [Los Alamos National Laboratory; Schwartz, Daniel S. [Los Alamos National Laboratory; Saleh, Tarik A. [Los Alamos National Laboratory; Migliori, Albert [Los Alamos National Laboratory

    2012-08-02

    Unalloyed polycrystalline Pu displays extreme thermal expansion behavior, i.e., {alpha} {yields} {beta} {yields} {gamma} {yields} {delta} increases by 25% in volume and {delta} {yields} {var_epsilon} {yields} liquid decreases by 4.5% in volume. Thus, making it difficult to measure density into the liquid state. Dilatometer outfitted with CaF molten metal cell offers a proven capability to measure thermal expansion in molten metals, but has yet to be proven for Pu. Historic data from the liquid nuclear fuels program will prove extremely useful as a guide to future measurements. 3.3at% Ga changes Pu molten metal properties: 50% increase in viscosity and {approx}3% decrease in density. Fe may decrease the density by a small amount assuming an averaging of densities for Pu-Ga and Pu-Fe liquids. More recent Boivineau (2009) work needs some interpretation, but technique is being employed in (U,Pu)O{sub 2} nuclear fuels program (Pu Futures, 2012).

  19. Liquid White Enamel.

    Science.gov (United States)

    Widmar, Marge

    1985-01-01

    A secondary teacher describes how she has her students use liquid white enamel. With the enameling process, students can create lasting, exciting artwork. They can exercise an understanding of design and color while learning the value of careful, sustained craft skills. (RM)

  20. Liquid crystalline dihydroazulene photoswitches

    DEFF Research Database (Denmark)

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

    2015-01-01

    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...

  1. Heavy liquid bubble chamber

    CERN Multimedia

    1965-01-01

    The CERN Heavy liquid bubble chamber being installed in the north experimental hall at the PS. On the left, the 1180 litre body; in the centre the magnet, which can produce a field of 26 800 gauss; on the right the expansion mechanism.

  2. Liquid Modernity & Late Capitalism

    DEFF Research Database (Denmark)

    Hansen, Claus D.

    In Liquid Modernity, Bauman portrays Adorno and the rest of the early Frankfurt School as sociologists and thinkers belonging to the ‘heavy’ phase of modernity. In other words, they are deemed irrelevant to the discussion of current sociological time diagnoses and the purpose of critique under co...

  3. Liquid metal embrittlement mechanism

    Institute of Scientific and Technical Information of China (English)

    周国辉; 刘晓敏; 万发荣; 乔利杰; 褚武扬; 张文清; 陈难先; 周富信

    1999-01-01

    Liquid metal embrittlement was studied in the following two aspects. First the first principle and ChenNanxian three-dimensional lattice reverse method were employed to obtain the effective potentials for Al-Ga and GaGa. Then with the molecular dynamics simulation, the influence of liquid metal adsorption on dislocation emission was studied. The simulated result shows that after Ga atoms are adsorbed on the crack plane in Al crystal, the critical stress intensity factor decreases, which changes from 0.5 MPam1/2 (without adsorption) to 0.4 MPam1/2 (with adsorption). The reason for the reduction in the critical intensity stress factor is that Ga adsorption reduces the surface energy of the crack plane. Moreover, 7075 Al alloy adsorbing liquid metal (Hg+3atm%Ga) was in-situ studied in TEM by using a special constant deflection device. The experimental result showed that liquid metal adsorption could facilitate emission, multiplication and motion of dislocations. When this process reached a critical

  4. ELECTRONS IN NONPOLAR LIQUIDS.

    Energy Technology Data Exchange (ETDEWEB)

    HOLROYD,R.A.

    2002-10-22

    Excess electrons can be introduced into liquids by absorption of high energy radiation, by photoionization, or by photoinjection from metal surfaces. The electron's chemical and physical properties can then be measured, but this requires that the electrons remain free. That is, the liquid must be sufficiently free of electron attaching impurities for these studies. The drift mobility as well as other transport properties of the electron are discussed here as well as electron reactions, free-ion yields and energy levels, Ionization processes typically produce electrons with excess kinetic energy. In liquids during thermalization, where this excess energy is lost to bath molecules, the electrons travel some distance from their geminate positive ions. In general the electrons at this point are still within the coulombic field of their geminate ions and a large fraction of the electrons recombine. However, some electrons escape recombination and the yield that escapes to become free electrons and ions is termed G{sub fi}. Reported values of G{sub fi} for molecular liquids range from 0.05 to 1.1 per 100 eV of energy absorbed. The reasons for this 20-fold range of yields are discussed here.

  5. Liquid White Enamel.

    Science.gov (United States)

    Widmar, Marge

    1985-01-01

    A secondary teacher describes how she has her students use liquid white enamel. With the enameling process, students can create lasting, exciting artwork. They can exercise an understanding of design and color while learning the value of careful, sustained craft skills. (RM)

  6. Thermodynamics of liquid metal

    Energy Technology Data Exchange (ETDEWEB)

    Kushnirenko, A.N.

    1988-01-01

    The thermodynamics of a liquid metal based on quantum-mechanical models of the crystal, electronic, and nuclear structures of the metal are derived in this paper. The models are based on such formulations as the Bohr radius, the Boltzmann constant, the Planck Law, the Fermi surface, and the Pauli principle.

  7. Supercooled Liquids and Glasses

    OpenAIRE

    1999-01-01

    In these lectures, which were presented at "Soft and Fragile Matter, Nonequilibrium Dynamics, Metastability and Flow" University of St. Andrews, 8 July - 22 July, 1999, I give an introduction to the physics of supercooled liquids and glasses and discuss some computer simulations done to investigate these systems.

  8. Liquidating a China Business

    Institute of Scientific and Technical Information of China (English)

    RICHARD; HOFFMANN

    2009-01-01

    With the global economic crisis hitting some businesses in China very hard as export sales dry up, now is a timely occasion to remind executives of affected businesses of their responsibilities when having to liquidate a business. China-based subsidiaries may

  9. Liquid Cooled Garments

    Science.gov (United States)

    1979-01-01

    Astronauts working on the surface of the moon had to wear liquid-cooled garments under their space suits as protection from lunar temperatures which sometimes reach 250 degrees Fahrenheit. In community service projects conducted by NASA's Ames Research Center, the technology developed for astronaut needs has been adapted to portable cooling systems which will permit two youngsters to lead more normal lives.

  10. Liquid rope coiling

    NARCIS (Netherlands)

    N.M. Ribe; M. Habibi; D. Bonn

    2012-01-01

    A thin stream or rope of viscous fluid falling from a sufficient height onto a surface forms a steadily rotating helical coil. Tabletop laboratory experiments in combination with a numerical model for slender liquid ropes reveal that finite-amplitude coiling can occur in four distinct regimes (visco

  11. The Heavenly Liquidity Twin : The Increasing Importance of Liquidity Risk

    OpenAIRE

    Montes-Negret, Fernando

    2009-01-01

    Liquidity and solvency have been called the "heavenly twins" of banking (Goodhart, Charles, 'Liquidity Risk Management', Financial Stability Review -- Special Issue on Liquidity, Banque de France, No. 11, February, 2008). Since these "twins" interact in complex ways, it is difficult -- particularly at times of crisis--to distinguish between them, especially in the presence of information a...

  12. Bubble wake dynamics in liquids and liquid-solid suspensions

    CERN Document Server

    Fan, Liang-Shih; Brenner, Howard

    1990-01-01

    This book is devoted to a fundamental understanding of the fluid dynamic nature of a bubble wake, more specifically the primary wake, in liquids and liquid-solid suspensions, an dto the role it plays in various important flow phenomena of multiphase systems. Examples of these phenomena are liquid/solids mixing, bubble coalescence and disintergration, particle entrainment to the freeboard, and bed contraction.

  13. The effect of liquid film on liquid droplet impingement erosion

    Energy Technology Data Exchange (ETDEWEB)

    Fujisawa, Nobuyuki, E-mail: fujisawa@eng.niigata-u.ac.jp [Visualization Research Center, Niigata University, 8050, Ikarashi 2-Nocho, Nishi-ku, Niigata 950-2181 (Japan); Yamagata, Takayuki, E-mail: yamagata@eng.niigata-u.ac.jp [Visualization Research Center, Niigata University, 8050, Ikarashi 2-Nocho, Nishi-ku, Niigata 950-2181 (Japan); Saito, Kengo; Hayashi, Kanto [Graduate School of Science and Technology, Niigata University, 8050, Ikarashi 2-Nocho, Nishi-ku, Niigata 950-2181 (Japan)

    2013-12-15

    Highlights: • Liquid droplet impingement erosion is studied experimentally using high-speed conical spray. • Erosion rate is increased with decreasing the liquid film thickness. • Erosion model is proposed considering the influence of liquid film thickness. -- Abstract: In the present paper, the pipe-wall thinning due to liquid droplet impingement erosion is studied experimentally by using a high-speed conical spray under the influences of liquid film on the target specimen. The size of the droplets considered is an order of tens of micrometers in diameter, which is the same order as those expected in the pipeline of nuclear/fossil power plants. In order to evaluate the erosion rate by the liquid droplet impingement under the influence of liquid film, the experiments are conducted by various combinations of the specimen diameters and the standoff distances of the spray from the nozzle. The experimental results show that the erosion depth increases linearly with the local flow volume, indicating the presence of terminal stage of erosion. The present results indicate that the erosion rate increases with decreasing the specimen diameter and increases slightly with increasing the standoff distance. This result combined with the theoretical consideration of the liquid film on the specimen leads to the conclusion that the erosion rate increases with decreasing the liquid film thickness, which supports the numerical result of liquid droplet impingement erosion in literature. Then, the erosion model for predicting the erosion rate by the liquid droplet impingement is proposed considering the influence of the liquid film.

  14. Gas absorption in an agitated gas-liquid-liquid system

    NARCIS (Netherlands)

    Cents, A.H.G.; Brilman, D.W.F.; Versteeg, G.F.

    2001-01-01

    Gas-liquid-liquid systems have gained interest in the past decade and are encountered in several important industrial applications. In these systems an immiscible liquid phase may affect the gas absorption rate significantly. This phenomenon, however, is not completely understood and underlying mech

  15. Black Liquid Solar Collector Demonstrator.

    Science.gov (United States)

    Weichman, F. L.; Austen, D. J.

    1979-01-01

    Describes the details of constructing, and use of, a solar collector. Uses a black liquid to absorb the energy, the thermosyphon effect to drive the liquid through the collector, and a floodlamp as a surrogate sun. (GA)

  16. Ionic liquids in chemical engineering.

    Science.gov (United States)

    Werner, Sebastian; Haumann, Marco; Wasserscheid, Peter

    2010-01-01

    The development of engineering applications with ionic liquids stretches back to the mid-1990s when the first examples of continuous catalytic processes using ionic liquids and the first studies of ionic liquid-based extractions were published. Ever since, the use of ionic liquids has seen tremendous progress in many fields of chemistry and engineering, and the first commercial applications have been reported. The main driver for ionic liquid engineering applications is to make practical use of their unique property profiles, which are the result of a complex interplay of coulombic, hydrogen bonding and van der Waals interactions. Remarkably, many ionic liquid properties can be tuned in a wide range by structural modifications at their cation and anion. This review highlights specific examples of ionic liquid applications in catalysis and in separation technologies. Additionally, the application of ionic liquids as working fluids in process machines is introduced.

  17. Citrem Modulates Internal Nanostructure of Glyceryl Monooleate Dispersions and Bypasses Complement Activation

    DEFF Research Database (Denmark)

    Wibroe, Peter P; Mat Azmi, Intan Diana Binti; Nilsson, Christa;

    2015-01-01

    Lyotropic non-lamellar liquid crystalline (LLC) aqueous nanodispersions hold a great promise in drug solubilization and delivery, but these nanosystems often induce severe hemolysis and complement activation, which limit their applications for safe intravenous administration. Here, we engineer an...

  18. Liquid bridge as a tunable-focus cylindrical liquid lens

    Science.gov (United States)

    Chen, H.; Tabatabaei, N.; Amirfazli, A.

    2017-01-01

    We proposed a method to create a tunable-focus cylindrical liquid lens using a liquid bridge between two narrow surfaces. Due to the surface edge effect, the interface of the liquid bridge (on the long side) was shown to be able to serve as a tunable-focus cylindrical liquid lens. The working distance of the lens can be adjusted by changing either or both of the height of the bridge (H) and the volume of the liquid (V). By varying H and V, the lens can serve as either diverging or converging lens, with a minimum working distance of 2.11 mm.

  19. Liquid lubrication for space applications

    Science.gov (United States)

    Fusaro, Robert L.; Khonsari, Michael M.

    1993-01-01

    Reviewed here is the state of the art of liquid lubrication for space applications. The areas discussed are types of liquid lubrication mechanisms, space environmental effects on lubrication, classification of lubricants, liquid lubricant additives, grease lubrication, mechanism materials, bearing anomalies and failures, lubricant supply techniques, and application types and lubricant needs for those applications.

  20. Risk allocation under liquidity constraints

    NARCIS (Netherlands)

    Csóka, P.; Herings, P.J.J.

    2013-01-01

    Risk allocation games are cooperative games that are used to attribute the risk of a financial entity to its divisions. In this paper, we extend the literature on risk allocation games by incorporating liquidity considerations. A liquidity policy specifies state-dependent liquidity requirements that

  1. The management of liquidity risk

    OpenAIRE

    Claudia MITITELU; Stefan MITITELU

    2009-01-01

    The importance of ensuring liquidity exceeds the level of a single banking institution, since recording of the deficit of liquidity only at the level of a single bank may have nevagtive repercurssions on the whole banking system, and entire national economy. Liquidity represents one the permanent concerns in banking management.

  2. Liquidity regulation and bank behavior

    NARCIS (Netherlands)

    Bonner, C.

    2014-01-01

    In response to the 2007-08 financial crisis, the Basel Committee on Banking Supervision proposed two liquidity standards to reinforce banks’ resilience to liquidity risks. The purpose of this thesis is to analyze the impact of liquidity regulation on bank behavior. The first of four main chapters

  3. Liquidity regulation and bank behavior

    NARCIS (Netherlands)

    Bonner, C.

    2014-01-01

    In response to the 2007-08 financial crisis, the Basel Committee on Banking Supervision proposed two liquidity standards to reinforce banks’ resilience to liquidity risks. The purpose of this thesis is to analyze the impact of liquidity regulation on bank behavior. The first of four main chapters an

  4. Liquid Crystal Motion Picture Projector①

    Institute of Scientific and Technical Information of China (English)

    SHIYongji

    1997-01-01

    A liquid crystal moving picture projector and method are described.Light incident on a liquid crystal display-type device is selectively scattered or transmitted by respective portions of liquid crystal display,and a projection mechanism projects an image formed by either such scattered light or such transmitted light.A liquid cystal moving picture projector includes a liquid crystal display for creating characteristics of an image,and projecttion optics for projecting images sequentially created by the display.The display includes a liquid crystal material capable of temporary storing information at respective areas.The temporary storage may be a function of charge storing directly on liquid crystal material.A method of projecting plural images in sequence includes:creating an image or characteristics of an image in a liquid crystal material,storing such image in such liquid crystal material,directing light at such liquid crystal material,projecting such image as a function of light transmitted through or scattered by such liquid crystal material,and creating a further image in such liquid crystal material for subsequent projection.

  5. Applications of functionalized ionic liquids

    Institute of Scientific and Technical Information of China (English)

    LI; Xuehui; ZHAO; Dongbin; FEI; Zhaofu; WANG; Lefu

    2006-01-01

    Recent developments of the synthesis and applications of functionalized ionic liquids(including dual-functionalized ionic liquids) have been highlighted in this review. Ionic liquids are attracting attention as alternative solvents in green chemistry, but as more functionalized ILs are prepared, a greater number of applications in increasingly diverse fields are found.

  6. The management of liquidity risk

    OpenAIRE

    Claudia MITITELU; Stefan MITITELU

    2009-01-01

    The importance of ensuring liquidity exceeds the level of a single banking institution, since recording of the deficit of liquidity only at the level of a single bank may have nevagtive repercurssions on the whole banking system, and entire national economy. Liquidity represents one the permanent concerns in banking management.

  7. Future liquid Argon detectors

    CERN Document Server

    Rubbia, A

    2013-01-01

    The Liquid Argon Time Projection Chamber offers an innovative technology for a new class of massive detectors for rare-event detection. It is a precise tracking device that allows three-dimensional spatial reconstruction with mm-scale precision of the morphology of ionizing tracks with the imaging quality of a "bubble chamber", provides $dE/dx$ information with high sampling rate, and acts as high-resolution calorimeter for contained events. First proposed in 1977 and after a long maturing process, its holds today the potentialities of opening new physics opportunities by providing excellent tracking and calorimetry performance at the relevant multi-kton mass scales, outperforming other techniques. In this paper, we review future liquid argon detectors presently being discussed by the neutrino physics community.

  8. Liquid Metal Dynamo Measurements

    Science.gov (United States)

    Luh, W. J.; Choi, Y. H.; Hardy, B. S.; Brown, M. R.

    1997-11-01

    Detection of convected magnetic fields in a small-scale liquid metal dynamo is attempted. Initial experiments will focus on the conversion of toroidal to poloidal flux (a version of the ω effect). A precision vector magnetometer will be used to measure the effect of a rotating magnetofluid on a static magnetic field. Water will be used as a control medium and effects will be compared with a conducting medium (liquid sodium or NaK). A small spherical flask (0.16 m diameter) houses 2 liters of fluid, a teflon stirrer creates an asymmetrical flow pattern, and Helmholtz coils generate a constant magnetic field on the order of 10 gauss. The Reynold's number will be of order unity.

  9. Model of Wigner liquid

    CERN Document Server

    Batyev, E G

    2001-01-01

    One studies a two-dimensional system of low-density charge carriers that is, with the strong Coulomb interaction that may lead to occurrence of a short-wave soft mode (sign of crystallization). Within this system there are elementary excitations of two types: Fermi-excitations and Bose-excitation with a slit within the spectrum (like rotons in a superfluid helium). The presented model represents a Fermi-liquid plus soft water. Interaction of different excitations with one another is described phenomenologically in terms of the theory of the Landau Fermi-liquid. One has derived equations the solution of which presents the dependence of the effective mass of Fermi-excitations and of slit in the Bose-excitation spectrum on temperature

  10. Liquid crystal dimers

    CERN Document Server

    Kumar Pal, Santanu

    2017-01-01

    This book covers in-depth discussion of design principles, synthesis and thermal behavior of all types of liquid crystal (LC) dimers. The text presents recent advances in the field of LC dimers consisting of different mesogenic units such as calamitic, discotic and bent-core molecules. It starts with a chapter on the introduction of liquid crystal dimers, including their odd-even behavior, basic classification of dimers and common mesophases in dimers. The text shows how the molecular architectures are being used to develop new materials to study a range of interesting phenomena such as the biaxial nematic phase containing rod-like and disc-like mesogenic units. Finally, the text presents perspectives related to technological relevance of these dimers such as dopants in LC display mixtures exhibiting faster relaxation time, strong flexoelectric coupling and others to effect control over the properties of these materials.

  11. Liquid crystal colloids

    CERN Document Server

    Muševič, Igor

    2017-01-01

    This book brings together the many concepts and discoveries in liquid crystal colloids contributed over the last twenty years and scattered across numerous articles and book chapters. It provides both a historical overview of the development of the field and a clear perspective on the future applications in photonics. The book covers all phenomena observed in liquid crystal colloids with an emphasis on experimental tools and applications of topology in condensed matter, as well as practical micro-photonics applications. It includes a number of spectacular manifestations of new topological phenomena not found or difficult to observe in other systems. Starting from the early works on nematic colloids, it explains the basics of topological defects in ordered media, charge and winding, and the elastic forces between colloidal particles in nematics. Following a detailed description of experimental methods, such as optical tweezing and particle tracking, the book eases the reader into the theoretical part, which de...

  12. Liquid Modernity & Late Capitalism

    DEFF Research Database (Denmark)

    Hansen, Claus D.

    conditions of such liquid modernity. In this paper, I want to argue that this picture of Adorno is mistaken and extend the view proposed by Frederic Jameson that Adorno was not only the philosopher of 1990’s but is also very useful in the 2010’s. In fact, the critique of critical theory and emancipation......In Liquid Modernity, Bauman portrays Adorno and the rest of the early Frankfurt School as sociologists and thinkers belonging to the ‘heavy’ phase of modernity. In other words, they are deemed irrelevant to the discussion of current sociological time diagnoses and the purpose of critique under....... The paper argues that there are great similarities but that Adorno (and the rest of the Early Frankfurt School) has a much more well founded philosophical layout of their critique of individualization....

  13. Safe and Liquid Mortgage Bonds

    DEFF Research Database (Denmark)

    Dick-Nielsen, Jens; Gyntelberg, Jacob; Lund, Jesper

    This paper shows that strict match pass-through funding of covered bonds provides safe and liquid mortgage bonds. Despite a 30% drop in house prices during the 2008 global crisis Danish mortgage bonds remained as liquid as most European government bonds. The Danish pass-through system effectively...... eliminates credit risk from the investor's perspective. Similar to other safe bonds, funding liquidity becomes the main driver of mortgage bond liquidity and this creates commonality in liquidity across markets and countries. These findings have implications for how to design a robust mortgage bond system...

  14. Safe and Liquid Mortgage Bonds

    DEFF Research Database (Denmark)

    Dick-Nielsen, Jens; Gyntelberg, Jacob; Lund, Jesper

    This paper shows that strict match pass-through funding of covered bonds provides safe and liquid mortgage bonds. Despite a 30% drop in house prices during the 2008 global crisis Danish mortgage bonds remained as liquid as most European government bonds. The Danish pass-through system effectively...... eliminates credit risk from the investor's perspective. Similar to other safe bonds, funding liquidity becomes the main driver of mortgage bond liquidity and this creates commonality in liquidity across markets and countries. These findings have implications for how to design a robust mortgage bond system...

  15. Liquidity Risk and Distressed Equity

    DEFF Research Database (Denmark)

    Medhat, Mamdouh

    , liquidity, and returns for US firms, I find evidence consistent with the model’s predictions: (1) In all solvency levels, the average firm holds enough liquid assets to cover its short-term liabilities; less solvent firms have (2) a higher fraction of their total assets in liquid assets and therefore (3......) lower conditional betas and (4) lower returns; (5) the profits of long-short solvency strategies are highest among firms with low liquidity; and (6) the profits of long-short liquidity strategies are highest among firms with low solvency....

  16. Liquid Scintillation Counting

    OpenAIRE

    Carlsson, Sten

    1993-01-01

    In liquid scintillation counting (LSC) we use the process of luminescense to detect ionising radiation emit$ed from a radionuclide. Luminescense is emission of visible light of nonthermal origin. 1t was early found that certain organic molecules have luminescent properties and such molecules are used in LSC. Today LSC is the mostwidespread method to detect pure beta-ernitters like tritium and carbon-14. 1t has unique properties in its efficient counting geometry, deteetability and the lack of...

  17. Liquids at negative pressure

    Science.gov (United States)

    Xiao, C.; Heyes, D. M.; Powles, J. G.

    2005-03-01

    We have further explored the final stages of the collapse of an unstable cavity or bubble using the Molecular Dynamics computer simulation technique. A nanometre sized spherical volume of molecules was removed from a bulk Lennard-Jones liquid, which being mechanically and thermodynamically unstable, proceeded to collapse. The molecules with the highest kinetic energy were the first to enter the initially empty cavity. The temperature of individual molecules inside the cavity, while the density was still typical of a gas, could reach at least an order of magnitude larger than that of the surrounding liquid, e.g., equivalent to 6,000 K for water, which is not unreasonable for the sonoluminescence effect to be seen. During the filling in of the cavity, the average temperature decreased, as the contents thermally equilibrated with the surrounding liquid. The bubble partially filled in, and then proceeded to partially empty again, and so on in an oscillatory manner, with ever decreasing amplitude towards the final uniform liquid state. This recoil effect is predicted by classical hydrodynamic treatments and has been observed in experiment for much larger bubbles. The temperature, density and normal pressure component were resolved as a function of radius from the centre of the bubble at selected times during the collapsing process. The simulations support the view that MD can provide a realistic representation of the final stages of cavity collapse. It does not make assumptions about equation of state and transport coefficients as would be required for a comparable solution of the Navier-Stokes hydrodynamics equations, and is therefore an especially appropriate description for the final stages of the collapse.

  18. Textures of liquid crystals

    CERN Document Server

    Dierking, Ingo

    2006-01-01

    A unique compendium of knowledge on all aspects of the texture of liquid crystals, providing not just detailed information on texture formation and determination, but also an in-depth discussion of different characterization methods. Experts as well as graduates entering the field will find all the information they need in this handbook, while the magnitude of the color images make it valuable hands-on-reference.

  19. The compression of liquids

    Science.gov (United States)

    Whalley, E.

    The compression of liquids can be measured either directly by applying a pressure and noting the volume change, or indirectly, by measuring the magnitude of the fluctuations of the local volume. The methods used in Ottawa for the direct measurement of the compression are reviewed. The mean-square deviation of the volume from the mean at constant temperature can be measured by X-ray and neutron scattering at low angles, and the meansquare deviation at constant entropy can be measured by measuring the speed of sound. The speed of sound can be measured either acoustically, using an acoustic transducer, or by Brillouin spectroscopy. Brillouin spectroscopy can also be used to study the shear waves in liquids if the shear relaxation time is > ∼ 10 ps. The relaxation time of water is too short for the shear waves to be studied in this way, but they do occur in the low-frequency Raman and infrared spectra. The response of the structure of liquids to pressure can be studied by neutron scattering, and recently experiments have been done at Atomic Energy of Canada Ltd, Chalk River, on liquid D 2O up to 15.6 kbar. They show that the near-neighbor intermolecular O-D and D-D distances are less spread out and at shorter distances at high pressure. Raman spectroscopy can also provide information on the structural response. It seems that the O-O distance in water decreases much less with pressure than it does in ice. Presumably, the bending of O-O-O angles tends to increase the O-O distance, and so to largely compensate the compression due to the direct effect of pressure.

  20. Liquid fuel cells.

    Science.gov (United States)

    Soloveichik, Grigorii L

    2014-01-01

    The advantages of liquid fuel cells (LFCs) over conventional hydrogen-oxygen fuel cells include a higher theoretical energy density and efficiency, a more convenient handling of the streams, and enhanced safety. This review focuses on the use of different types of organic fuels as an anode material for LFCs. An overview of the current state of the art and recent trends in the development of LFC and the challenges of their practical implementation are presented.

  1. Nanomechanical sensing in liquid

    OpenAIRE

    Dorrestijn, Marko

    2006-01-01

    This thesis describes advances in the field of nanomechanical sensors operating in liquid. Firstly, a novel method for measuring nanoscale displacements is presented. Secondly, microscale Chladnifigures are demonstrated on oscillating cantilevers by means of boundary streaming in the aqueous environment. Thirdly, the physics of boundary streaming is clarified for the first time. The three topics are summarized below. A novel displacement sensor based on a squeezable molecular m...

  2. Refractoriless liquid fuel burner

    Energy Technology Data Exchange (ETDEWEB)

    Musil, J.E.

    1986-07-15

    A liquid fuel burner head is described which consists of: A. a generally annular burner head housing spacedly enveloping a generally cylindrical primary air assembly, the head and assembly each having corresponding forward and rearward ends, (a) the primary air assembly having a plurality of internal primary air supply passage means extending in a generally forwardly direction in the assembly and emerging through annularly disposed primary air port means at the forward end of the primary air assembly, (b) means effective to produce a swirl of primary air in one direction about the axis of the primary air assembly as the air emerges from the primary air port means, (c) means associated with the primary air port means for adjusting the location of flame origin forward of and relative to the primary air port means, (d) the primary air assembly including a liquid fuel supply passage and a nozzle, the nozzle being centrally disposed at the forward end of the primary air assembly and encompassed by the primary air port means, the liquid fuel nozzle being effective to discharge a substantially fan-like spray of liquid fuel just forward of and across the primary air port means, (e) the primary air assembly and the nozzle together being axially movable relative to the housing between forwardmost and rearwardmost positions respectively responsive to change in burner firing rate between minimum and maximum; B. secondary air supply passage means disposed in the space between the housing and the primary air assembly; C. means rearwardly of the secondary air directional means and port means effective to meter the amount of secondary air supplied air port means from a lesser quantity when the primary air assembly and nozzle are in their forwardmost position to a greater quantity when the primary air assembly and nozzle are in their rearwardmost position.

  3. Cyclic phosphonium ionic liquids

    Directory of Open Access Journals (Sweden)

    Sharon I. Lall-Ramnarine

    2014-01-01

    Full Text Available Ionic liquids (ILs incorporating cyclic phosphonium cations are a novel category of materials. We report here on the synthesis and characterization of four new cyclic phosphonium bis(trifluoromethylsulfonylamide ILs with aliphatic and aromatic pendant groups. In addition to the syntheses of these novel materials, we report on a comparison of their properties with their ammonium congeners. These exemplars are slightly less conductive and have slightly smaller self-diffusion coefficients than their cyclic ammonium congeners.

  4. Liquid krypton electromagnetic calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    Aulchenko, V.M.; Bukin, A.D.; Klimenko, S.G.; Kolachev, G.M.; Leontiev, L.A.; Maslennikov, A.L.; Onuchin, A.P.; Panin, V.S.; Peleganchuk, S.V.; Pivovarov, S.G.; Rodyakin, V.A.; Tayursky, V.A.; Tikhonov, Yu.A.; Yurchenko, V.I. (Budker Inst. of Nuclear Physics, Novosibirsk (Russia)); Lanni, F.; Lo Bianco, G.; Maggi, B.; Palombo, F.; Sala, A. (Dipt. di Fisica, Univ. Milan (Italy) INFN, Milan (Italy)); Cantoni, P.; Frabetti, P.L.; Stagni, L. (Dipt. di Fisica, Univ. Bologna (Italy) INFN, Bologna (Italy)); Manfredi, P.F.; Re, V.; Speziali, V. (Dipt. di Elettronica, Univ. Pavia (Italy) INFN, Milan (Italy))

    1993-03-20

    A calorimeter using 30 tons of liquid krypton for the KEDR detector is being constructed. The main effects which determine the energy and space resolution have been studied. An energy resolution of 1.7% at 1.2 GeV was obtained with the prototype. A space resolution of 0.4 mm for relativistic particles has been reached with the prototype. (orig.).

  5. Advanced Liquid Feed Experiment

    Science.gov (United States)

    Distefano, E.; Noll, C.

    1993-06-01

    The Advanced Liquid Feed Experiment (ALFE) is a Hitchhiker experiment flown on board the Shuttle of STS-39 as part of the Space Test Payload-1 (STP-1). The purpose of ALFE is to evaluate new propellant management components and operations under the low gravity flight environment of the Space Shuttle for eventual use in an advanced spacecraft feed system. These components and operations include an electronic pressure regulator, an ultrasonic flowmeter, an ultrasonic point sensor gage, and on-orbit refill of an auxiliary propellant tank. The tests are performed with two transparent tanks with dyed Freon 113, observed by a camera and controlled by ground commands and an on-board computer. Results show that the electronic pressure regulator provides smooth pressure ramp-up, sustained pressure control, and the flexibility to change pressure settings in flight. The ultrasonic flowmeter accurately measures flow and detects gas ingestion. The ultrasonic point sensors function well in space, but not as a gage during sustained low-gravity conditions, as they, like other point gages, are subject to the uncertainties of propellant geometry in a given tank. Propellant transfer operations can be performed with liquid-free ullage equalization at a 20 percent fill level, gas-free liquid transfer from 20-65 percent fill level, minimal slosh, and can be automated.

  6. Instabilities in liquid crystals

    CERN Document Server

    Barclay, G J

    1998-01-01

    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...

  7. Some Cavitation Properties of Liquids

    Directory of Open Access Journals (Sweden)

    K. D. Efremova

    2016-01-01

    Full Text Available Cavitation properties of liquid must be taken into consideration in the engineering design of hydraulic machines and hydro devices when there is a possibility that in their operation an absolute pressure in the liquid drops below atmospheric one, and for a certain time the liquid is in depression state. Cold boiling, which occurs at a comparatively low temperature under a reduced absolute pressure within or on the surface of the liquid is regarded as hydrostatic cavitation if the liquid is stationary or as hydrodynamic cavitation, if the liquid falls into conditions when in the flow cross-section there is a sharply increasing dynamic pressure and a dropping absolute pressure.In accordance with the theory of cavitation, the first phase of cavitation occurs when the absolute pressure of the degassed liquid drops to the saturated vapour pressure, and the air dissolved in the liquid, leaving the intermolecular space, is converted into micro-bubbles of combined air and becomes a generator of cavitation “nuclei”. A quantitative estimate of the minimum allowable absolute pressure in a real, fully or partially degassed liquid at which a hydrostatic cavitation occurs is of practical interest.Since the pressure of saturated vapour of a liquid is, to a certain extent, related to the forces of intermolecular interaction, it is necessary to have information on the cavitation properties of technical solutions, including air solution in a liquid, as a solute may weaken intermolecular bonds and affect the pressure value of the saturated solvent vapour. In the experiment to carry out vacuum degassing of liquids was used a hydraulic air driven vacuum pump.The paper presents hydrostatic and hydrodynamic degassing liquid processes used in the experiment.The experimental studies of the cavitation properties of technical liquids (sea and distilled water, saturated NaCl solution, and pure glycerol and as a 49/51% solution in water, mineral oil and jet fuel enabled

  8. Probing liquid surface waves, liquid properties and liquid films with light diffraction

    CERN Document Server

    Barik, T K; Kar, S; Roy, A; Barik, Tarun Kr.; Chaudhuri, Partha Roy; Kar, Sayan; Roy, Anushree

    2005-01-01

    Surface waves on liquids act as a dynamical phase grating for incident light. In this article, we revisit the classical method of probing such waves (wavelengths of the order of mm) as well as inherent properties of liquids and liquid films on liquids, using optical diffraction. A combination of simulation and experiment is proposed to trace out the surface wave profiles in various situations (\\emph{eg.} for one or more vertical, slightly immersed, electrically driven exciters). Subsequently, the surface tension and the spatial damping coefficient (related to viscosity) of a variety of liquids are measured carefully in order to gauge the efficiency of measuring liquid properties using this optical probe. The final set of results deal with liquid films where dispersion relations, surface and interface modes, interfacial tension and related issues are investigated in some detail, both theoretically and experimentally. On the whole, our observations and analyses seem to support the claim that this simple, low--c...

  9. Simulation of Multistage Countercurrent Liquid-Liquid Extraction

    Directory of Open Access Journals (Sweden)

    Annasaheb WARADE

    2012-08-01

    Full Text Available Liquid-Liquid Extraction is one of the most significant unit operations used widely in the chemical industry for the separation of liquid-liquid mixture with the aid of an extracting solvent. There are different contacting patterns for the said purpose viz. co-current, counter current and crosscurrent and also a variety of equipments are encountered. This paper deals with the simulation of counter current liquid-liquid extraction operation for the special case of immiscible solvent using MATLAB. In this paper seven case studies have been studied and the results obtained are compared with the literature and it was found that results are in good agreement with the literature available.

  10. Application of ionic liquid in liquid phase microextraction technology.

    Science.gov (United States)

    Han, Dandan; Tang, Baokun; Lee, Yu Ri; Row, Kyung Ho

    2012-11-01

    Ionic liquids (ILs) are novel nonmolecular solvents. Their unique properties, such as high thermal stability, tunable viscosity, negligible vapor pressure, nonflammability, and good solubility for inorganic and organic compounds, make them excellent candidates as extraction media for a range of microextraction techniques. Many physical properties of ILs can be varied, and the structural design can be tuned to impart the desired functionality and enhance the analyte extraction selectivity, efficiency, and sensitivity. This paper provides an overview of the applications of ILs in liquid phase microextraction technology, such as single-drop microextraction, hollow fiber based liquid phase microextraction, and dispersive liquid-liquid microextraction. The sensitivity, linear calibration range, and detection limits for a range of target analytes in the methods were analyzed to determine the advantages of ILs in liquid phase microextraction. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Nanosecond liquid crystalline optical modulator

    Energy Technology Data Exchange (ETDEWEB)

    Borshch, Volodymyr; Shiyanovskii, Sergij V.; Lavrentovich, Oleg D.

    2016-07-26

    An optical modulator includes a liquid crystal cell containing liquid crystal material having liquid crystal molecules oriented along a quiescent director direction in the unbiased state, and a voltage source configured to apply an electric field to the liquid crystal material wherein the direction of the applied electric field does not cause the quiescent director direction to change. An optical source is arranged to transmit light through or reflect light off the liquid crystal cell with the light passing through the liquid crystal material at an angle effective to undergo phase retardation in response to the voltage source applying the electric field. The liquid crystal material may have negative dielectric anisotropy, and the voltage source configured to apply an electric field to the liquid crystal material whose electric field vector is transverse to the quiescent director direction. Alternatively, the liquid crystal material may have positive dielectric anisotropy and the voltage source configured to apply an electric field to the liquid crystal material whose electric field vector is parallel with the quiescent director direction.

  12. Entropy-driven liquid-liquid separation in supercooled water

    OpenAIRE

    Holten, V.; Anisimov, M.A.

    2012-01-01

    Twenty years ago Poole et al. (Nature 360, 324, 1992) suggested that the anomalous properties of supercooled water may be caused by a critical point that terminates a line of liquid-liquid separation of lower-density and higher-density water. Here we present an explicit thermodynamic model based on this hypothesis, which describes all available experimental data for supercooled water with better quality and with fewer adjustable parameters than any other model suggested so far. Liquid water a...

  13. Impulse breakdown of liquids

    CERN Document Server

    Ushakov, Vasily Y

    2007-01-01

    The book describes the main physical processes and phenomena in pulsed electric breakdown. The knowledge and the control of the electric breakdown of liquids is important not only for the insulation inside power systems but it is also used for the creation and information of high voltage and high current pulses. Such high-voltage micro- and nanosecond pulses find wide application in experimental physics, electro discharge technology, physics of dielectrics, radar detection and ranging, high-speed photography. The nature of charge carriers, mechanism of formation and evolution of the gas phase,

  14. High Performance Liquid Chromatography

    Science.gov (United States)

    Talcott, Stephen

    High performance liquid chromatography (HPLC) has many applications in food chemistry. Food components that have been analyzed with HPLC include organic acids, vitamins, amino acids, sugars, nitrosamines, certain pesticides, metabolites, fatty acids, aflatoxins, pigments, and certain food additives. Unlike gas chromatography, it is not necessary for the compound being analyzed to be volatile. It is necessary, however, for the compounds to have some solubility in the mobile phase. It is important that the solubilized samples for injection be free from all particulate matter, so centrifugation and filtration are common procedures. Also, solid-phase extraction is used commonly in sample preparation to remove interfering compounds from the sample matrix prior to HPLC analysis.

  15. Molecular Relaxation in Liquids

    CERN Document Server

    Bagchi, Biman

    2012-01-01

    This book brings together many different relaxation phenomena in liquids under a common umbrella and provides a unified view of apparently diverse phenomena. It aligns recent experimental results obtained with modern techniques with recent theoretical developments. Such close interaction between experiment and theory in this area goes back to the works of Einstein, Smoluchowski, Kramers' and de Gennes. Development of ultrafast laser spectroscopy recently allowed study of various relaxation processes directly in the time domain, with time scales going down to picosecond (ps) and femtosecond (fs

  16. Nanorheology of Liquid Alkanes

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, S.A., Cochran, H.D., Cummings, P.T. [Tennessee Univ., Knoxville, TN (United States). Dept. of Chemical Engineering], [Oak Ridge National Lab., TN (United States)

    1997-09-01

    We report molecular dynamics simulations of liquid alkanes, squalane and tetracosane, confined between moving walls to which butane chains are tethered, effectively screening the details of the wall. As in an experiment, heat is removed by thermostatting the tethered molecules. Results obtained at high strain rates, typical of practical applications, suggest little or no difference between the bulk rheology and confined flow, and the occurrence of a high degree of slip at the wall-fluid interface at the conditions studied. At relatively low velocities and high densities, tetracosane shows the formation of fully-extended chains at certain wall spacings.

  17. Berry Fermi liquid theory

    Science.gov (United States)

    Chen, Jing-Yuan; Son, Dam Thanh

    2017-02-01

    We develop an extension of the Landau Fermi liquid theory to systems of interacting fermions with non-trivial Berry curvature. We propose a kinetic equation and a constitutive relation for the electromagnetic current that together encode the linear response of such systems to external electromagnetic perturbations, to leading and next-to-leading orders in the expansion over the frequency and wave number of the perturbations. We analyze the Feynman diagrams in a large class of interacting quantum field theories and show that, after summing up all orders in perturbation theory, the current-current correlator exactly matches with the result obtained from the kinetic theory.

  18. Micellar liquid chromatography

    Science.gov (United States)

    Basova, Elena M.; Ivanov, Vadim M.; Shpigun, Oleg A.

    1999-12-01

    Background and possibilities of practical applications of micellar liquid chromatography (MLC) are considered. Various retention models in MLC, the effects of the nature and concentration of surfactants and organic modifiers, pH, temperature and ionic strength on the MLC efficiency and selectivity are discussed. The advantages and limitations of MLC are demonstrated. The performance of MLC is critically evaluated in relationship to the reversed-phase HPLC and ion-pair chromatography. The potential of application of MLC for the analysis of pharmaceuticals including that in biological fluids and separation of inorganic anions, transition metal cations, metal chelates and heteropoly compounds is described. The bibliography includes 146 references.

  19. Liquidity, welfare and distribution

    Directory of Open Access Journals (Sweden)

    Martín Gil Samuel

    2012-01-01

    Full Text Available This work presents a dynamic general equilibrium model where wealth distribution is endogenous. I provide channels of causality that suggest a complex relationship between financial markets and the real activity which breaks down the classical dichotomy. As a consequence, the Friedman rule does not hold. In terms of the current events taking place in the world economy, this paper provides a rationale to advert against the perils of an economy satiated with liquidity. Efficiency and distribution cannot thus be considered as separate attributes once we account for the interactions between financial markets and the economic performance.

  20. Principles of Liquid Chromatography

    Science.gov (United States)

    Bakalyar, Stephen R.

    This article reviews the basic principles of high performance liquid chromatography (HPLC). The introductory section provides an overview of the HPLC technique, placing it in historical context and discussing the elementary facts of the separation mechanism. The next section discusses the nature of resolution, describing the two principal aspects, zone center separation and zone spreading. The third section takes a detailed look at how HPLC is used in practice to achieve a separation. It discusses the three key variables that need to be adjusted: retention, efficiency, and selectivity. A fourth section is concerned with various relationships of practical importance: flow rate, temperature, and pressure. A final section discusses future trends in HPLC.

  1. Cavitation in liquid helium

    Energy Technology Data Exchange (ETDEWEB)

    Finch, R. D.; Kagiwada, R.; Barmatz, M.; Rudnick, I.

    1963-11-15

    Ultrasonic cavitation was induced in liquid helium over the temperature range 1.2 to 2.3 deg K, using a pair of identical transducers. The transducers were calibrated using a reciprocity technique and the cavitation threshold was determined at 90 kc/s. It was found that this threshold has a sharp peak at the lambda point, but is, at all temperatures quite low, with an approximate range of 0.001 to 0.01 atm. The significance of the results is discussed. (auth)

  2. Rheology of Lamellar Liquid Crystal Formed from Nonyl Phenol Ethoxylate(10) and Water%壬基酚聚氧乙烯醚(10)/水体系层状液晶的流变性

    Institute of Scientific and Technical Information of China (English)

    冯尚华; 张翠娟; 李衍飞

    2012-01-01

    采用应力控制流变仪,研究了非离子表面活性剂壬基酚聚氧乙烯醚(10)(NP-10)/水体系层状液晶在不同温度和表面活性剂质量分数的流变性.在线性黏弹区内,其储能模量和损耗模量与频率的关系不符合Maxwell模型,并用滑移模型、范德华力、水化作用解释了非离子表面活性剂层状液晶表现此类流变性的原因;用Burgers模型解释了蠕变-回复实验的结论,其结果与线性的振荡实验一致.%The rheological behavior of a lamellar lyotropic liquid crystal formed from nonyl phenol ethoxylate (10) (NP-10)/water was investigated using a rheometer. The influence of composition and temperature on the dynamic function was studied at varied surfactant concentration and temperature. The frequency-dependent storage and loss modulus were found not to be consistent with the Maxwell model in the linear viscoelastic region. The results were analyzed on the basis of slip-plane theory. The compliance was also measured, and the instantaneous elasticity measured in the creep tests was in according with the oscillatory tests. Burgers model was used to describe the time-dependent compliance.

  3. Liquid marbles: Physics and applications

    Indian Academy of Sciences (India)

    Nachiketa Janardan; Mahesh V Panchagnula; Edward Bormashenko

    2015-05-01

    Liquid marbles are formed by encapsulating microscale volume of liquid in a particulate sheath. The marble thus formed is robust and resists rupture if the particulate layer covers the entire volume of liquid and prevents contact between the liquid and the substrate. Liquid marbles have been objects of study over the past decade. Research has been focused on understanding their formation and properties – both static and dynamic. A range of particulate materials as well as liquids have been employed to make these objects. This paper summarizes the state of the art in this regard and discusses new developments that are being discussed. Finally, some directions are proposed based on lacunae observed in the community’s understanding – both in terms of the science as well as on the application front.

  4. Qualitative and quantitative analysis of chemical constituents in traditional Chinese medicinal formula Tong-Xie-Yao-Fang by high-performance liquid chromatography/diode array detection/electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Yan, Zhixiang; Yang, Xinghao; Wu, Jianbo; Su, Huai; Chen, Chen; Chen, Yin

    2011-04-08

    Tong-Xie-Yao-Fang (TXYF), a famous traditional Chinese medicine formula, has efficient effects on treatment of the diarrhea-predominant irritable bowel syndrome (D-IBS), a disease with high incidence worldwide. However, the active principles for this complex formula have not been fully explored so far. In this paper, high-performance liquid chromatography coupled with diode array detection and electrospray ionization tandem mass spectrometry (HPLC-DAD-ESI-MS/MS) was applied for the qualitative and quantitative analysis of major chemical constituents in TXYF. Two monoterpene glycosides, one chromone and five polymethoxylated flavones were tentatively characterized based on the retention times, UV spectra and MS data. Fifteen compounds were unambiguously identified by comparison with reference standards. Constituents such as lactone and steroidal, which could not be found by single HPLC method due to the low content in the formula, were identified in this paper. Seven compounds (gallic acid, prim-O-β-D-glucosylcimifugin, paeoniflorin, cimifugin, naringin, hesperidin and 4'-O-β-D-glucosyl-5-O-methylvisamminol) were quantified by HPLC-DAD using a C18 column and gradient elution with acetonitrile and water-0.1% formic acid. The method exhibited intra- and inter-day precision of less than 2.35% and 3.14%, respectively. The LODs and the LOQs for the analytes were less than 0.47 and 1.82 μg ml(-1), respectively. The overall recoveries ranged from 96.82% to 102.47%, with the R.S.D. ranging from 1.17% to 3.94%. These results demonstrated that our present method was effective and reliable for comprehensive quality evaluation of TXYF. Meanwhile, the study might provide the chemical evidence for revealing the material basis of its therapeutic effects. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Liquid-Liquid Extraction in Systems Containing Butanol and Ionic Liquids – A Review

    Directory of Open Access Journals (Sweden)

    Kubiczek Artur

    2017-03-01

    Full Text Available Room-temperature ionic liquids (RTILs are a moderately new class of liquid substances that are characterized by a great variety of possible anion-cation combinations giving each of them different properties. For this reason, they have been termed as designer solvents and, as such, they are particularly promising for liquid-liquid extraction, which has been quite intensely studied over the last decade. This paper concentrates on the recent liquid-liquid extraction studies involving ionic liquids, yet focusing strictly on the separation of n-butanol from model aqueous solutions. Such research is undertaken mainly with the intention of facilitating biological butanol production, which is usually carried out through the ABE fermentation process. So far, various sorts of RTILs have been tested for this purpose while mostly ternary liquid-liquid systems have been investigated. The industrial design of liquid-liquid extraction requires prior knowledge of the state of thermodynamic equilibrium and its relation to the process parameters. Such knowledge can be obtained by performing a series of extraction experiments and employing a certain mathematical model to approximate the equilibrium. There are at least a few models available but this paper concentrates primarily on the NRTL equation, which has proven to be one of the most accurate tools for correlating experimental equilibrium data. Thus, all the presented studies have been selected based on the accepted modeling method. The reader is also shown how the NRTL equation can be used to model liquid-liquid systems containing more than three components as it has been the authors’ recent area of expertise.

  6. Bank Mergers, Competition and Liquidity

    OpenAIRE

    Carletti, Elena; Hartmann, Philipp; Spagnolo, Giancarlo

    2004-01-01

    We model the impact of bank mergers on loan competition, reserve holdings and aggregate liquidity. A merger changes the distribution of liquidity shocks and creates an internal money market, leading to financial cost efficiencies and more precise estimates of liquidity needs. The merged banks may increase their reserve holdings through an internalization effect or decrease them because of a diversification effect. The merger also affects loan market competition, which in turn modifies the dis...

  7. Market liquidity and financial stability.

    OpenAIRE

    CROCKETT, A.

    2008-01-01

    Stability in financial institutions and in financial markets are closely intertwined. Banks and other financial institutions need liquid markets through which to conduct risk management. And markets need the back-up liquidity lines provided by financial institutions. Market liquidity depends not only on objective, exogenous factors, but also on endogenous market dynamics. Central banks responsible for systemic stability need to consider how far their traditional responsibility for the health ...

  8. Graphene-ionic liquid composites

    Science.gov (United States)

    Aksay, Ilhan A.; Korkut, Sibel; Pope, Michael; Punckt, Christian

    2016-11-01

    Method of making a graphene-ionic liquid composite. The composite can be used to make elec-trodes for energy storage devices, such as batteries and supercapacitors. Dis-closed and claimed herein is method of making a graphene-ionic liquid com-posite, comprising combining a graphene source with at least one ionic liquid and heating the combination at a temperature of at least about 130 .degree. C.

  9. Radon Removal from Liquid Xenon

    Energy Technology Data Exchange (ETDEWEB)

    Martens, Kai [IPMU, The University of Tokyo, 456 Higashi-Mozumi, Kamioka-cho, Hida-shi, Gifu 506-1205 (Japan)

    2012-08-15

    Efforts are underway in Kamioka to develop a new method to remove Rn directly from the liquid phase of Xe. The idea is based on the observation that in the electronic structure of liquid noble gases charges can get trapped on impurities, and the charged impurities then be drifted through the noble gas liquid. In the case of Rn drifting the impurity into a suitable storage volume is enough as it will decay.

  10. Liquidity Determinants of Moroccan Banking Industry

    OpenAIRE

    FERROUHI, El Mehdi; LEHADIRI, Abderrassoul

    2013-01-01

    This paper analyzes the behavior of Moroccan bank’s liquidity during the period 2001 – 2012. The research aims to identify the determinants of Moroccan bank’s liquidity. We first evaluate Moroccan banks’ liquidity positions through different liquidity ratios to determine the effects of financial crisis on bank’s liquidity. We then highlight the effect of banks’ size on banks’ liquidity. Finally, we identify determinants of Moroccan bank’s liquidity using panel data regression. From results ob...

  11. Liquidity (risk) concepts: definitions and interactions

    OpenAIRE

    Nikolaou, Kleopatra

    2009-01-01

    We discuss the notion of liquidity and liquidity risk within the financial system. We distinguish between three different liquidity types, central bank liquidity, funding and market liquidity and their relevant risks. In order to understand the workings of financial system liquidity, as well as the role of the central bank, we bring together relevant literature from different areas and review liquidity linkages among these three types in normal and turbulent times. We stress that the root of ...

  12. Nanoconfined Ionic Liquids.

    Science.gov (United States)

    Zhang, Shiguo; Zhang, Jiaheng; Zhang, Yan; Deng, Youquan

    2016-12-29

    Ionic liquids (ILs) have been widely investigated as novel solvents, electrolytes, and soft functional materials. Nevertheless, the widespread applications of ILs in most cases have been hampered by their liquid state. The confinement of ILs into nanoporous hosts is a simple but versatile strategy to overcome this problem. Nanoconfined ILs constitute a new class of composites with the intrinsic chemistries of ILs and the original functions of solid matrices. The interplay between these two components, particularly the confinement effect and the interactions between ILs and pore walls, further endows ILs with significantly distinct physicochemical properties in the restricted space compared to the corresponding bulk systems. The aim of this article is to provide a comprehensive review of nanoconfined ILs. After a brief introduction of bulk ILs, the synthetic strategies and investigation methods for nanoconfined ILs are documented. The local structure and physicochemical properties of ILs in diverse porous hosts are summarized in the next sections. The final section highlights the potential applications of nanoconfined ILs in diverse fields, including catalysis, gas capture and separation, ionogels, supercapacitors, carbonization, and lubrication. Further research directions and perspectives on this topic are also provided in the conclusion.

  13. Vitrification and levitation of a liquid droplet on liquid nitrogen

    Science.gov (United States)

    Song, Young S.; Adler, Douglas; Xu, Feng; Kayaalp, Emre; Nureddin, Aida; Anchan, Raymond M.; Maas, Richard L.; Demirci, Utkan

    2010-01-01

    The vitrification of a liquid occurs when ice crystal formation is prevented in the cryogenic environment through ultrarapid cooling. In general, vitrification entails a large temperature difference between the liquid and its surrounding medium. In our droplet vitrification experiments, we observed that such vitrification events are accompanied by a Leidenfrost phenomenon, which impedes the heat transfer to cool the liquid, when the liquid droplet comes into direct contact with liquid nitrogen. This is distinct from the more generally observed Leidenfrost phenomenon that occurs when a liquid droplet is self-vaporized on a hot plate. In the case of rapid cooling, the phase transition from liquid to vitrified solid (i.e., vitrification) and the levitation of droplets on liquid nitrogen (i.e., Leidenfrost phenomenon) take place simultaneously. Here, we investigate these two simultaneous physical events by using a theoretical model containing three dimensionless parameters (i.e., Stefan, Biot, and Fourier numbers). We explain theoretically and observe experimentally a threshold droplet radius during the vitrification of a cryoprotectant droplet in the presence of the Leidenfrost effect. PMID:20176969

  14. Aromatic nitrations by mixed acid. Fast liquid-liquid regime

    NARCIS (Netherlands)

    Zaldivar, J.M.; Zaldivar, J.M.; Molga, E.J.; Alos, M.A.; Hernandez, H.; Westerterp, K.R.

    1996-01-01

    Aromatic nitration by mixed acid was selected as a specific case of heterogeneous liquid-liquid reaction. An extensive experimental programme was followed using adiabatic and heat flow calorimetry and pilot reactor experiments, supported by chemical analysis. A series of nitration experiments was

  15. Performance of sonication and microfluidization for liquid-liquid emulsification.

    Science.gov (United States)

    Maa, Y F; Hsu, C C

    1999-05-01

    The purpose of this research was to evaluate and compare liquid-liquid emulsions (water-in-oil and oil-in-water) prepared using sonication and microfluidization. Liquid-liquid emulsions were characterized on the basis of emulsion droplet size determined using a laser-based particle size analyzer. An ultrasonic-driven benchtop sonicator and an air-driven microfluidizer were used for emulsification. Sonication generated emulsions through ultrasound-driven mechanical vibrations, which caused cavitation. The force associated with implosion of vapor bubbles caused emulsion size reduction and the flow of the bubbles resulted in mixing. An increase in viscosity of the dispersion phase improved the sonicator's emulsification capability, but an increase in the viscosity of the dispersed phase decreased the sonicator's emulsification capability. Although sonication might be comparable to homogenization in terms of emulsification efficiency, homogenization was relatively more effective in emulsifying more viscous solutions. Microfluidization, which used a high pressure to force the fluid into microchannels of a special configuration and initiated emulsification via a combined mechanism of cavitation, shear, and impact, exhibited excellent emulsification efficiency. Of the three methodologies, sonication generated more heat and might be less suitable for emulsion systems involving heat-sensitive materials. Homogenization is in general a more effective liquid-liquid emulsification method. The results derived from this study can serve as a basis for the evaluation of large-scale liquid-liquid emulsification in the microencapsulation process.

  16. Nanomaterials at Liquid/Liquid Interfaces-A Review.

    Science.gov (United States)

    Divya, V; Sangaranarayanan, M V

    2015-09-01

    The charge transfer processes occurring at the interface between two immiscible electrolyte solutions are of considerable importance in diverse fields of chemistry and biology. The introduction to nanoparticles and analysis of nanostructures in diverse branches of science and engineering are provided. The chemical and electrochemical techniques pertaining to the synthesis of metal nanoparticles, polymeric nanostructures and metal-polymer nanocomposites at liquid/liquid interfaces are surveyed. The unique features pertaining to the chemical synthesis of metal nanoparticles while employing diverse electrolytes and solvents are outlined. The advantages of various electrochemical synthetic protocols such as four-electrode assembly, thin film electrode, Scanning Electrochemical Microscopy and Solid/liquid/liquid interfaces for the study of nanoparticles at liquid/liquid interfaces are emphasized. The crucial role played by the liquid/liquid interfaces in altering the morphological patterns of metal nanoparticles, conducting polymers and metal-polymer nanocomposites is indicated. A few typical novel applications of these nanomaterials in fabrication of biosensors, electrochemical supercapacitors, and electrocatalysts have been outlined.

  17. Spectrophotometric determination of iron species using ionic liquid ultrasound assisted dispersive liquid--liquid microextraction

    OpenAIRE

    BAZMANDEGAN, ALIREZA; Shabani,Ali Mohammad Haji; DADFARNIA, SAYESSTEH; Saeidi, Mahboubeh; Moghadam,Masoud Rohani

    2015-01-01

    A simple and efficient method for speciation and determination of iron in different water samples was developed. The method is based on ionic liquid ultrasound assisted dispersive liquid--liquid microextraction (IL-USA-DLLME) followed by spectrophotometric determination. Fe(II) is complexed with 2,4,6-tri(2'-pyridyl)-l,3,5-triazine (TPTZ{)}, neutralized through ion pair formation with sodium dodecyl sulfate (SDS) and extracted into 1-hexyl-3-methylimidazolium hexafluorophosphate [C$_...

  18. Ionic liquids, electrolyte solutions including the ionic liquids, and energy storage devices including the ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Gering, Kevin L.; Harrup, Mason K.; Rollins, Harry W.

    2015-12-08

    An ionic liquid including a phosphazene compound that has a plurality of phosphorus-nitrogen units and at least one pendant group bonded to each phosphorus atom of the plurality of phosphorus-nitrogen units. One pendant group of the at least one pendant group comprises a positively charged pendant group. Additional embodiments of ionic liquids are disclosed, as are electrolyte solutions and energy storage devices including the embodiments of the ionic liquid.

  19. Polymer Crystallization at Curved Liquid/Liquid Interface

    Science.gov (United States)

    Wang, Wenda

    Liquid/liquid interface, either flat or curved, is a unique template for studying self-assembly of a variety of nanomaterials such as nanoparticles and nanorods. The resultant monolayer films can be ordered or disordered depending on the regularity of the nanomaterials. Integration of nanoparticles into two-dimensional structure leads to intriguing collective properties of the nanoparticles. Crystallization can also be guided by liquid/liquid interface. Due to the particular shape of the interface, crystallization can happen in a different manner comparing to the normal solution crystallization. In this dissertation, liquid/liquid interface is employed to guide the crystallization of polymers, mainly focusing on using curved liquid/liquid interface. Due to the unique shape of the interface and feasibility to control the curvature, polymer crystallization can take place in different manner and lead to the formation of curved or vesicular crystals. Curved liquid/liquid interface is typically created through o/w emulsions. With the presence of surfactant, the emulsions are controlled to be stable at least for the polymer crystallization periods. The difference to normal solution crystallization is: the nuclei will diffuse to the curved interface due to the Pickering effect and guide the crystallization along the curved liquid/liquid interface. If the supercooling can be controlled to be very small, crystal growth in the bulk droplets can be avoided. The advantages of this strategy are: 1) the formation process of vesicular type crystals can be monitored by controlling the polymer supply; 2) curved crystals, bowl-like structures and enclosed capsules can be easily obtained comparing to the self-assembly method for vesicle formation; 3) the obtained vesicles will be made of polymer crystals, which will possess the extraordinary mechanical properties. Based on the nucleation type, this dissertation is divided into two parts. The first part is focused on the self

  20. Liquid crystal polyester thermosets

    Science.gov (United States)

    Benicewicz, Brian C.; Hoyt, Andrea E.

    1992-01-01

    The present invention provides (1) curable liquid crystalline polyester monomers represented by the formula: R.sup.1 --A.sup.1 --B.sup.1 --A.sup.2 --B.sup.2 --A.sup.3 --R.sup.2 where R.sup.1 and R.sup.2 are radicals selected from the group consisting of maleimide, substituted maleimide, nadimide, substituted naimide, ethynyl, and (C(R.sup.3).sub.2).sub.2 where R.sup.3 is hydrogen with the proviso that the two carbon atoms of (C(R.sup.3).sub.2).sub.2 are bound on the aromatic ring of A.sup.1 or A.sup.3 to adjacent carbon atoms, A.sup.1 and A.sup.3 are 1,4-phenylene and the same where said group contains one or more substituents selected from the group consisting of halo, e.g., fluoro, chloro, bromo, or iodo, nitro lower alkyl, e.g., methyl, ethyl, or propyl, alkoxy, e.g., methoxy, ethoxy, or propoxy, and fluoroalkyl, e.g., trifluoromethyl, pentafluoroethyl and the like, A.sup.2 is selected from the group consisting of 1,4-phenylene, 4,4'-biphenyl, 2,6-naphthylene and the same where said groups contain one or more substituents selected from the group consisting of halo, e.g., fluoro, chloro, bromo, or iodo, nitro, lower alkyl, e.g., methyl, ethyl, and propyl, lower alkoxy, e.g., methoxy, ethoxy, or propoxy, and fluoroalkyl or fluoroalkoxy, e.g., trifluoromethyl, pentafluoroethyl and the like, and B.sup.1 and B.sup.2 are selected from the group consisting of --C(O)--O-- and --O--C(O)--, (2) thermoset liquid crystalline polyester compositions comprised of heat-cured segments derived from monomers represented by the formula: R.sup.1 --A.sup.1 --B.sup.1 --A.sup.2 --B.sup.2 --A.sup.3 --R.sup.2 as described above, (3) curable blends of at least two of the polyester monomers and (4) processes of preparing the curable liquid crystalline polyester monomers.

  1. Correlation of three-liquid-phase equilibria involving ionic liquids.

    Science.gov (United States)

    Rodríguez-Escontrela, I; Arce, A; Soto, A; Marcilla, A; Olaya, M M; Reyes-Labarta, J A

    2016-08-03

    The difficulty in achieving a good thermodynamic description of phase equilibria is finding a model that can be extended to a large variety of chemical families and conditions. This problem worsens in the case of systems containing more than two phases or involving complex compounds such as ionic liquids. However, there are interesting applications that involve multiphasic systems, and the promising features of ionic liquids suggest that they will play an important role in many future processes. In this work, for the first time, the simultaneous correlation of liquid-liquid and liquid-liquid-liquid equilibrium data for ternary systems involving ionic liquids has been carried out. To that end, the phase diagram of the water + [P6 6 6 14][DCA] + hexane system has been determined at 298.15 K and 323.15 K and atmospheric pressure. The importance of this system lies in the possibility of using the surface active ionic liquid to improve surfactant enhanced oil recovery methods. With those and previous measurements, thirteen sets of equilibrium data for water + ionic liquid + oil ternary systems have been correlated. The isoactivity equilibrium condition, using the NRTL model, and some pivotal strategies are proposed to correlate these complex systems. Good agreement has been found between experimental and calculated data in all the regions (one triphasic and two biphasic) of the diagrams. The geometric aspects related to the Gibbs energy of mixing function obtained using the model, together with the minor common tangent plane equilibrium condition, are valuable tools to check the consistency of the obtained correlation results.

  2. Method of foaming a liquid metal

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, A.K.; Johnson, C.E.

    1980-01-15

    The addition of a small quantity of barium to liquid metal NaK or sodium has been found to promote foam formation and improve bubble retention in the liquid metal. A stable liquid metal foam will provide a more homogeneous liquid metal flow through the channel of a two-phase liquid metal MHD power generator to improve operating efficiency.

  3. Method of foaming a liquid metal

    Science.gov (United States)

    Fischer, Albert K.; Johnson, Carl E.

    1980-01-01

    The addition of a small quantity of barium to liquid metal NaK or sodium has been found to promote foam formation and improve bubble retention in the liquid metal. A stable liquid metal foam will provide a more homogeneous liquid metal flow through the channel of a two-phase liquid metal MHD power generator to improve operating efficiency.

  4. Efficiency in Liquidity Matters

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    While stocks plunge on investors’ fears over tightening credit in China, the U.S. Federal Reserve has decided to maintain its current interest rates near zero until a sustainable economic recovery is underway. When the recovery is in sight, U.S. demand for imports will soon return, raising hopes for China’s export sector-but a possible U.S. dollar rally may also cause capital outflows from emerging markets where hot money has pushed up assets prices. Yuan Zhigang, Dean of the School of Economics in Fudan University, spoke with 21st Century Business Herald about the efficiency of liquidity, and provided solutions to asset price hikes. Edited excerpts follow

  5. Taylor Instability of Incompressible Liquids

    Science.gov (United States)

    Fermi, E.; von Neumann, J.

    1955-11-01

    A discussion is presented in simplified form of the problem of the growth of an initial ripple on the surface of an incompressible liquid in the presence of an acceleration, g, directed from the outside into the liquid. The model is that of a heavy liquid occupying at t = 0 the half space above the plane z = 0, and a rectangular wave profile is assumed. The theory is found to represent correctly one feature of experimental results, namely the fact that the half wave of the heavy liquid into the vacuum becomes rapidly narrower while the half wave pushing into the heavy liquid becomes more and more blunt. The theory fails to account for the experimental results according to which the front of the wave pushing into the heavy liquid moves with constant velocity. The case of instability at the boundary of 2 fluids of different densities is also explored. Similar results are obtained except that the acceleration of the heavy liquid into the light liquid is reduced.

  6. Liquid ethylene-propylene copolymers

    Science.gov (United States)

    Rhein, R. A.; Ingham, J. D.; Humphrey, M. F.

    1975-01-01

    Oligomers are prepared by heating solid ethylene-propylene rubber in container that retains solid and permits liquid product to flow out as it is formed. Molecular weight and viscosity of liquids can be predetermined by process temperature. Copolymers have low viscosity for given molecular weight.

  7. Lipid processing in ionic liquids

    DEFF Research Database (Denmark)

    Lue, Bena-Marie; Guo, Zheng; Xu, Xuebing

    2007-01-01

    Ionic liquids (ILs) have been touted as “green” alternatives to traditional molecular solvents and have many unique properties which make them extremely desirable substitutes. Among their most attractive properties are their lack of vapour pressure, broad liquid range, strong solvating power...

  8. Tethered float liquid level sensor

    Energy Technology Data Exchange (ETDEWEB)

    Daily, III, William Dean

    2016-09-06

    An apparatus for sensing the level of a liquid includes a float, a tether attached to the float, a pulley attached to the tether, a rotation sensor connected to the pulley that senses vertical movement of said float and senses the level of the liquid.

  9. Modeling liquid crystal polymeric devices

    Science.gov (United States)

    Gimenez Pinto, Vianney Karina

    The main focus of this work is the theoretical and numerical study of materials that combine liquid crystal and polymer. Liquid crystal elastomers are polymeric materials that exhibit both the ordered properties of the liquid crystals and the elastic properties of rubbers. Changing the order of the liquid crystal molecules within the polymer network can induce shape change. These materials are very valuable for applications such as actuators, sensors, artificial muscles, haptic displays, etc. In this work we apply finite element elastodynamics simulations to study the temperature induced shape deformation in nematic elastomers with complex director microstructure. In another topic, we propose a novel numerical method to model the director dynamics and microstructural evolution of three dimensional nematic and cholesteric liquid crystals. Numerical studies presented in this work are in agreement with experimental observations and provide insight into the design of application devices.

  10. The Liquid Argon Purity Demonstrator

    CERN Document Server

    Adamowski, M; Dvorak, E; Hahn, A; Jaskierny, W; Johnson, C; Jostlein, H; Kendziora, C; Lockwitz, S; Pahlka, B; Plunkett, R; Pordes, S; Rebel, B; Schmitt, R; Stancari, M; Tope, T; Voirin, E; Yang, T

    2014-01-01

    The Liquid Argon Purity Demonstrator was an R&D test stand designed to determine if electron drift lifetimes adequate for large neutrino detectors could be achieved without first evacuating the cryostat. We describe here the cryogenic system, its operations, and the apparatus used to determine the contaminant levels in the argon and to measure the electron drift lifetime. The liquid purity obtained by this system was facilitated by a gaseous argon purge. Additionally, gaseous impurities from the ullage were prevented from entering the liquid at the gas-liquid interface by condensing the gas and filtering the resulting liquid before returning to the cryostat. The measured electron drift lifetime in this test was greater than 6 ms, sustained over several periods of many weeks. Measurements of the temperature profile in the argon, to assess convective flow and boiling, were also made and are compared to simulation.

  11. The Liquid Argon Purity Demonstrator

    Energy Technology Data Exchange (ETDEWEB)

    Adamowski, M.; Carls, B.; Dvorak, E.; Hahn, A.; Jaskierny, W.; Johnson, C.; Jostlein, H.; Kendziora, C.; Lockwitz, S.; Pahlka, B.; Plunkett, R.; Pordes, S.; Rebel, B.; Schmitt, R.; Stancari, M.; Tope, T.; Voirin, E.; Yang, T.

    2014-07-01

    The Liquid Argon Purity Demonstrator was an R&D test stand designed to determine if electron drift lifetimes adequate for large neutrino detectors could be achieved without first evacuating the cryostat. We describe here the cryogenic system, its operations, and the apparatus used to determine the contaminant levels in the argon and to measure the electron drift lifetime. The liquid purity obtained by this system was facilitated by a gaseous argon purge. Additionally, gaseous impurities from the ullage were prevented from entering the liquid at the gas-liquid interface by condensing the gas and filtering the resulting liquid before returning to the cryostat. The measured electron drift lifetime in this test was greater than 6 ms, sustained over several periods of many weeks. Measurements of the temperature profile in the argon, to assess convective flow and boiling, were also made and are compared to simulation.

  12. An Efficient Liquidity Management For ATMs

    National Research Council Canada - National Science Library

    Julia García Cabello

    2013-01-01

      Bank liquidity management has become one of the main concerns of a bank during the financial crisis as liquidity shortages have put pressure on banks to diversity and improve their liquidity sources...

  13. Hydrotreating of coal-derived liquids

    Energy Technology Data Exchange (ETDEWEB)

    Lott, S.E.; Stohl, F.V.; Diegert, K.V. [Sandia National Lab., Albuquerque, NM (United States)] [and others

    1995-12-31

    To develop a database relating hydrotreating parameters to feed and product quality by experimentally evaluating options for hydrotreating whole coal liquids, distillate cuts of coal liquids, petroleum, and blends of coal liquids with petroleum.

  14. Progress of surface grafted nano cellulose whiskers and their liquid crystals%纳米纤维素晶须表面接枝及其液晶性能研究进展

    Institute of Scientific and Technical Information of China (English)

    杨洁; 叶代勇

    2012-01-01

    作为一种新兴的纳米生物材料,纳米纤维素日益受到各界的广泛关注,对其进行表面接枝改性并开发新的功能是十分必要的。本文综述了纳米纤维素晶须表面接枝的技术及研究进展,主要介绍了传统自由基聚合、离子和开环聚合及活性自由基聚合技术,包括氮氧自由基调控活性聚合、原子转移自由基聚合、可逆加成-断裂链转移聚合、单电子转移活性自由基聚合,讨论了各种接枝聚合方法的适用范围和优缺点。简述了点击化学在纳米纤维素晶须表面接枝的应用。通过各种聚合方法改性得到的纳米纤维素晶须接枝共聚物往往具有一些特殊的功能,某些接枝共聚物在适当的溶剂中可以形成液晶态,本文重点介绍了接枝改性的纳米纤维素晶须的液晶性能及其形成机理和影响因素等。%Nano cellulose has received much attention as a new nano biomaterial.Surface grafting modification of nano cellulose is used to develop new functional nanomaterials.The surface grafting methods of nano cellulose whiskers(NCW) are reviewed,such as conventional free radical graft copolymerization,ionic and ring opening graft polymerization and living radical polymerization,which includes nitroxide-mediated polymerization(NMP),atom transfer radical polymerization(ATRP),reversible addition–fragmentation chain transfer polymerization(RAFT) and single electron transfer living radical polymerization(SET-LRP).The application of click chemistry in the surface grafting modification of NCW is summarized.The formation of lyotropic liquid crystal and thermotropic liquid crystal is also discussed.The formation mechanism and the factors affecting cholesteric liquid crystals of NCW are discussed.

  15. Separating closely resembling steroids with ionic liquids in liquid-liquid extraction systems

    NARCIS (Netherlands)

    Vitasari, C.R.; Gramblicka, M.; Gibcus, K.; Visser, T.J.; Geertman, R.M.; Schuur, B.

    2015-01-01

    Separation of steroids by liquid–liquid extraction with ionic liquids (ILs) as solvent was studied both experimentally and by simulation using a model mixture of progesterone and pregnenolone. The studies involved a solvent screening using COSMO-RS software for estimation of progesterone solubility.

  16. Comment on "Liquid Limits: The Glass Transition and Liquid-Gas Spinodal Boundaries of Metastable Liquids"

    OpenAIRE

    2000-01-01

    In ref. cond-mat/0005372, Sastry studies by numerical simulations the phase diagram of a simple fragile glass-forming liquid, presenting very interesting and clear results. We apply to this system, at various density values, the analytic approach to structural glass thermodynamics recently introduced and we compare our theoretical predictions on the liquid-glass transition temperature with Sastry's data.

  17. Convenient liquidity measure for Financial markets

    OpenAIRE

    Oleh Danyliv; Bruce Bland; Daniel Nicholass

    2014-01-01

    A liquidity measure based on consideration and price range is proposed. Initially defined for daily data, Liquidity Index (LIX) can also be estimated via intraday data by using a time scaling mechanism. The link between LIX and the liquidity measure based on weighted average bid-ask spread is established. Using this liquidity measure, an elementary liquidity algebra is possible: from the estimation of the execution cost, the liquidity of a basket of instruments is obtained. A formula for the ...

  18. Liquid Cell Transmission Electron Microscopy

    Science.gov (United States)

    Liao, Hong-Gang; Zheng, Haimei

    2016-05-01

    Liquid cell transmission electron microscopy (TEM) has attracted significant interest in recent years. With nanofabricated liquid cells, it has been possible to image through liquids using TEM with subnanometer resolution, and many previously unseen materials dynamics have been revealed. Liquid cell TEM has been applied to many areas of research, ranging from chemistry to physics, materials science, and biology. So far, topics of study include nanoparticle growth and assembly, electrochemical deposition and lithiation for batteries, tracking and manipulation of nanoparticles, catalysis, and imaging of biological materials. In this article, we first review the development of liquid cell TEM and then highlight progress in various areas of research. In the study of nanoparticle growth, the electron beam can serve both as the illumination source for imaging and as the input energy for reactions. However, many other research topics require the control of electron beam effects to minimize electron beam damage. We discuss efforts to understand electron beam-liquid matter interactions. Finally, we provide a perspective on future challenges and opportunities in liquid cell TEM.

  19. Actively convected liquid metal divertor

    Science.gov (United States)

    Shimada, Michiya; Hirooka, Yoshi

    2014-12-01

    The use of actively convected liquid metals with j × B force is proposed to facilitate heat handling by the divertor, a challenging issue associated with magnetic fusion experiments such as ITER. This issue will be aggravated even more for DEMO and power reactors because the divertor heat load will be significantly higher and yet the use of copper would not be allowed as the heat sink material. Instead, reduced activation ferritic/martensitic steel alloys with heat conductivities substantially lower than that of copper, will be used as the structural materials. The present proposal is to fill the lower part of the vacuum vessel with liquid metals with relatively low melting points and low chemical activities including Ga and Sn. The divertor modules, equipped with electrodes and cooling tubes, are immersed in the liquid metal. The electrode, placed in the middle of the liquid metal, can be biased positively or negatively with respect to the module. The j × B force due to the current between the electrode and the module provides a rotating motion for the liquid metal around the electrodes. The rise in liquid temperature at the separatrix hit point can be maintained at acceptable levels from the operation point of view. As the rotation speed increases, the current in the liquid metal is expected to decrease due to the v × B electromotive force. This rotating motion in the poloidal plane will reduce the divertor heat load significantly. Another important benefit of the convected liquid metal divertor is the fast recovery from unmitigated disruptions. Also, the liquid metal divertor concept eliminates the erosion problem.

  20. Liquid Hole Multipliers: bubble-assisted electroluminescence in liquid xenon

    CERN Document Server

    Arazi, L; Coimbra, A E C; Rappaport, M L; Vartsky, D; Chepel, V; Breskin, A

    2015-01-01

    In this work we discuss the mechanism behind the large electroluminescence signals observed at relatively low electric fields in the holes of a Thick Gas Electron Multiplier (THGEM) electrode immersed in liquid xenon. We present strong evidence that the scintillation light is generated in xenon bubbles trapped below the THGEM holes. The process is shown to be remarkably stable over months of operation, providing - under specific thermodynamic conditions - energy resolution similar to that of present dual-phase liquid xenon experiments. The observed mechanism may serve as the basis for the development of Liquid Hole Multipliers (LHMs), capable of producing local charge-induced electroluminescence signals in large-volume single-phase noble-liquid detectors for dark matter and neutrino physics experiments.