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Sample records for ternary amphiphilic fluid

  1. LB3D: A parallel implementation of the Lattice-Boltzmann method for simulation of interacting amphiphilic fluids

    Science.gov (United States)

    Schmieschek, S.; Shamardin, L.; Frijters, S.; Krüger, T.; Schiller, U. D.; Harting, J.; Coveney, P. V.

    2017-08-01

    We introduce the lattice-Boltzmann code LB3D, version 7.1. Building on a parallel program and supporting tools which have enabled research utilising high performance computing resources for nearly two decades, LB3D version 7 provides a subset of the research code functionality as an open source project. Here, we describe the theoretical basis of the algorithm as well as computational aspects of the implementation. The software package is validated against simulations of meso-phases resulting from self-assembly in ternary fluid mixtures comprising immiscible and amphiphilic components such as water-oil-surfactant systems. The impact of the surfactant species on the dynamics of spinodal decomposition are tested and quantitative measurement of the permeability of a body centred cubic (BCC) model porous medium for a simple binary mixture is described. Single-core performance and scaling behaviour of the code are reported for simulations on current supercomputer architectures.

  2. Dynamical fluctuation of the mesoscopic structure in ternary C12E5-water-n-octane amphiphilic system.

    Science.gov (United States)

    Komura, S; Takeda, T; Kawabata, Y; Ghosh, S K; Seto, H; Nagao, M

    2001-04-01

    Dynamical fluctuations of the bicontinuous microemulsion and lamellar structures in ternary C12E5-water-n-octane amphiphilic system are studied by means of neutron spin echo (NSE) spectrometry. The decay rates of the time correlation of the concentration were analyzed in terms of three theories: (1) A. G. Zilman and R. Granek, Phys. Rev. Lett. 77, 4788 (1996), (2) M. Nonomura and T. Ohta, J. Chem. Phys. 110, 7516 (1999), and (3) R. Granek and M. E. Cates, Phys. Rev. A 46, 3319 (1992), in the first of which a Langevin equation for membrane plaquettes and in the latter two of which time-dependent Ginzburg-Landau equations for the order parameters are considered. The result shows that the intermediate correlation functions I(q,t) for the ranges of 0

  3. Neutron spin echo studies of the effects of temperature and pressure in a ternary microemulsion

    CERN Document Server

    Kawabata, Y; Seto, H; Takeda, T; Komura, S; Schwahn, D

    2002-01-01

    In order to clarify the self-assembling mechanisms in complex fluids involving amphiphiles, we have investigated dynamic features of amphiphilic membranes and droplets at high temperature and at high pressure in a ternary microemulsion, consisting of AOT, water, and n-decane. A high-pressure cell for neutron spin echo (NSE) experiments has been improved, and the static and dynamic features of droplets are observed in detail by means of small angle neutron scattering and NSE. It is found that the size fluctuation and the diffusion of droplets are enhanced by increasing temperature, while they are suppressed by increasing pressure. (orig.)

  4. Dependence of the Internal Structure on Water/Particle Volume Ratio in an Amphiphilic Janus Particle-Water-Oil Ternary System: From Micelle-like Clusters to Emulsions of Spherical Droplets.

    Science.gov (United States)

    Noguchi, Tomohiro G; Iwashita, Yasutaka; Kimura, Yasuyuki

    2017-01-31

    Amphiphilic Janus particles (AJP), composed of hydrophilic and hydrophobic hemispheres, are one of the simplest anisotropic colloids, and they exhibit higher surface activities than particles with homogeneous surface properties. Consequently, a ternary system of AJP, water, and oil can form extremely stable Pickering emulsions, with internal structures that depend on the Janus structure of the particles and the system composition. However, the detail of these structures has not been fully explored, especially for the composition range where the amount of the minority liquid phase and AJP are comparable, where one would expect the Janus characteristics to be directly reflected. In this study, we varied the volume ratio of the particles and the minority liquid phase, water, by 2 orders of magnitude around the comparable composition range, and observed the resultant structures at the resolution of the individual particle dimensions by optical microscopy. When the volume ratio of water is smaller than that of the Janus particles, capillary interactions between the hydrophilic hemispheres of the particles induce micelle-like clusters in which the hydrophilic sides of the particles face inward. With increasing water content, these clusters grow into a rodlike morphology. When the water volume exceeds that of the particles, the structure transforms into an emulsion state composed of spherical droplets, colloidosomes, because of the surface activity of particles at the liquid-liquid interface. Thus, we found that a change in volume fraction alters the mechanism of structure formation in the ternary system, and large resulting morphological changes in the self-assembled structures reflect the anisotropy of the particles. The self-assembly shows essential commonalities with that in microemulsions of surfactant molecules, however the AJP system is stabilized only kinetically. Analysis of the dependence of the emulsion droplet size on composition shows that almost all the

  5. Extensive characterization of human tear fluid collected using different techniques unravels the presence of novel lipid amphiphiles1[S

    Science.gov (United States)

    Lam, Sin Man; Tong, Louis; Duan, Xinrui; Petznick, Andrea; Wenk, Markus R.; Shui, Guanghou

    2014-01-01

    The tear film covers the anterior eye and the precise balance of its various constituting components is critical for maintaining ocular health. The composition of the tear film amphiphilic lipid sublayer, in particular, has largely remained a matter of contention due to the limiting concentrations of these lipid amphiphiles in tears that render their detection and accurate quantitation tedious. Using systematic and sensitive lipidomic approaches, we validated different tear collection techniques and report the most comprehensive human tear lipidome to date; comprising more than 600 lipid species from 17 major lipid classes. Our study confers novel insights to the compositional details of the existent tear film model, in particular the disputable amphiphilic lipid sublayer constituents, by demonstrating the presence of cholesteryl sulfate, O-acyl-ω-hydroxyfatty acids, and various sphingolipids and phospholipids in tears. The discovery and quantitation of the relative abundance of various tear lipid amphiphiles reported herein are expected to have a profound impact on the current understanding of the existent human tear film model. PMID:24287120

  6. Ternary fission

    Indian Academy of Sciences (India)

    2015-08-05

    Aug 5, 2015 ... We present the ternary fission of 252Cf and 236U within a three-cluster model as well as in a level density approach. The competition between collinear and equatorial geometry is studied by calculating the ternary fragmentation potential as a function of the angle between the lines joining the stationary ...

  7. Ternary fission

    Indian Academy of Sciences (India)

    Recently, we have studied the various aspects associated with the ternary fission process. A model, called the three-cluster model (TCM) [1–6] has been put forth. This accounts for the energy minimization of all possible ternary breakups of a heavy radioactive nucleus. Further, within the TCM we have analysed the ...

  8. Amphiphilicity is essential for mitochondrial presequence function.

    OpenAIRE

    Roise, D; Theiler, F; Horvath, S J; Tomich, J M; Richards, J H; Allison, D S; Schatz, G

    1988-01-01

    We have shown earlier that a mitochondrial presequence peptide can form an amphiphilic helix. However, the importance of amphiphilicity for mitochondrial presequence function became doubtful when an artificial presequence, designed to be non-amphiphilic, proved to be active as a mitochondrial import signal. We now show experimentally that this 'non-amphiphilic' presequence peptide is, in fact, highly amphiphilic as measured by its ability to insert into phospholipid monolayers and to disrupt ...

  9. Phase equilibria of a lattice model for an oil{endash}water{endash}amphiphile mixture

    Energy Technology Data Exchange (ETDEWEB)

    Mackie, A.D.; Onur, K.; Panagiotopoulos, A.Z. [School of Chemical Engineering, Cornell University, Ithaca, New York 14853-5201 (United States)

    1996-03-01

    Monte Carlo simulation and quasichemical theory are used to study the phase behavior of a lattice model for oil{endash}water{endash}amphiphile ternary systems. Several short amphiphiles with varying tail and head lengths are studied. Two- and three-phase coexistence regions are observed as well as the formation of microemulsions. In contrast to previous work on this model, quantitative phase diagrams are determined for both symmetric and asymmetric amphiphiles. The removal and regrowth of whole chains by configurational bias methods is used to help equilibration and sampling. Near quantitative agreement is found between quasichemical theory and our simulations except when one of the phases self-assembles or in the vicinity of a critical point. In these areas the quasichemical theory is still qualitatively correct. {copyright} {ital 1996 American Institute of Physics.}

  10. Amphiphilicity is essential for mitochondrial presequence function.

    Science.gov (United States)

    Roise, D; Theiler, F; Horvath, S J; Tomich, J M; Richards, J H; Allison, D S; Schatz, G

    1988-03-01

    We have shown earlier that a mitochondrial presequence peptide can form an amphiphilic helix. However, the importance of amphiphilicity for mitochondrial presequence function became doubtful when an artificial presequence, designed to be non-amphiphilic, proved to be active as a mitochondrial import signal. We now show experimentally that this 'non-amphiphilic' presequence peptide is, in fact, highly amphiphilic as measured by its ability to insert into phospholipid monolayers and to disrupt phospholipid vesicles. This result, and similar tests on three additional artificial presequences (two functionally active and one inactive), revealed that all active presequences were amphiphilic whereas the inactive presequence was non-amphiphilic. One of the active presequence peptides was non-helical in solution and in the presence of detergent micelles. We conclude that amphiphilicity is necessary for mitochondrial presequence function whereas a helical structure may not be essential.

  11. Ternary chalcopyrite semiconductors

    CERN Document Server

    Shay, J L; Pamplin, B R

    2013-01-01

    Ternary Chalcopyrite Semiconductors: Growth, Electronic Properties, and Applications covers the developments of work in the I-III-VI2 and II-IV-V2 ternary chalcopyrite compounds. This book is composed of eight chapters that focus on the crystal growth, characterization, and applications of these compounds to optical communications systems. After briefly dealing with the status of ternary chalcopyrite compounds, this book goes on describing the crystal growth of II-IV-V2 and I-III-VI2 single crystals. Chapters 3 and 4 examine the energy band structure of these semiconductor compounds, illustrat

  12. Amphiphilic block copolymers as efficiency boosters in microemulsions a SANS investigation of the role of polymers

    CERN Document Server

    Endo, H; Mihailescu, M; Monkenbusch, M; Gompper, G; Richter, D; Jakobs, B; Sottmann, T; Strey, R

    2002-01-01

    The effect of amphiphilic block copolymers on ternary microemulsions (water, oil and non-ionic surfactant) is investigated. Small amounts of PEP-PEO block copolymer lead to a dramatic expansion of the one-phase region where water and oil can be solubilized by the mediation of surfactant molecules. Small-angle neutron-scattering experiments employing a high-precision two-dimensional contrast-variation technique demonstrate that the polymer is distributed uniformly on the surfactant membrane, where it modifies the membrane curvature elasticity. Furthermore, a new approach to determine the bending rigidity of an amphiphilic membrane is proposed, which is precise enough to measure the logarithmic scale dependence of the bending rigidity and its universal prefactor in bicontinuous microemulsions. (orig.)

  13. Amphiphilic block copolymers as efficiency boosters in microemulsions: a SANS investigation of the role of polymers

    Energy Technology Data Exchange (ETDEWEB)

    Endo, H.; Allgaier, J.; Mihailescu, M.; Monkenbusch, M.; Gompper, G.; Richter, D. [Institut fuer Festkoeperforschung, Forschungszentrum Juelich, 52425 Juelich (Germany); Jakobs, B.; Sottmann, T.; Strey, R. [Institut fuer Physikalische Chemie, Universitaet zu Koeln, Luxemburger Str. 116, 50939 Koeln (Germany)

    2002-07-01

    The effect of amphiphilic block copolymers on ternary microemulsions (water, oil and non-ionic surfactant) is investigated. Small amounts of PEP-PEO block copolymer lead to a dramatic expansion of the one-phase region where water and oil can be solubilized by the mediation of surfactant molecules. Small-angle neutron-scattering experiments employing a high-precision two-dimensional contrast-variation technique demonstrate that the polymer is distributed uniformly on the surfactant membrane, where it modifies the membrane curvature elasticity. Furthermore, a new approach to determine the bending rigidity of an amphiphilic membrane is proposed, which is precise enough to measure the logarithmic scale dependence of the bending rigidity and its universal prefactor in bicontinuous microemulsions. (orig.)

  14. Solvent-free, molecular-level modeling of self-assembling amphiphiles in water

    Science.gov (United States)

    Dey, Somajit; Saha, Jayashree

    2017-02-01

    Aggregation mesophases of self-assembling amphiphiles in water are highly important in the context of biology (biomembranes), therapy (liposomes), industry (polymer surfactants), and condensed-matter physics (lyotropic liquid crystals). Besides helping to increase fundamental understanding of collective molecular behavior, simulations of these lyotropic phases are pivotal to technological and medical developments such as smart drug carriers for gene therapy. Implicit-solvent, coarse-grained, low resolution modeling with a simple pair potential is the key to realizing the larger length and time scales associated with such mesoscopic phenomena during a computer simulation. Modeling amphiphiles by directed, soft, ellipsoidal cores interacting via a computationally simple yet tunable anisotropic pair potential, we have come to such a single-site model amphiphile that can rapidly self-assemble to give diverse lyotropic phases (such as fluid bilayers, micelles, etc.) without requiring the explicit incorporation of solvent particles. The model directly represents a tunable packing parameter that manifests in the spontaneous curvature of the amphiphile aggregates. Besides the all-important hydrophobic interaction, the hydration force is also treated implicitly. Thanks to the efficient solvent-free molecular-level coarse graining, this model is suitable for generic mesoscale studies of phenomena such as self-assembly, amphiphile mixing, domain formation, fusion, elasticity, etc., in amphiphile aggregates.

  15. Polymer films removed from solid surfaces by nanostructured fluids: microscopic mechanism and implications for the conservation of cultural heritage.

    Science.gov (United States)

    Raudino, Martina; Selvolini, Giulia; Montis, Costanza; Baglioni, Michele; Bonini, Massimo; Berti, Debora; Baglioni, Piero

    2015-03-25

    Complex fluids based on amphiphilic formulations are emerging, particularly in the field of conservation of works of art, as effective and safe liquid media for the removal of hydrophobic polymeric coatings. The comprehension of the cleaning mechanism is key to designing tailored fluids for this purpose. However, the interaction between nanostructured fluids and hydrophobic polymer films is still poorly understood. In this study, we show how the combination of confocal laser scanning microscopy (CLSM) and atomic force microscopy (AFM) provides interesting and complementary insight into this process. We focused on the interaction between an ethyl methacrylate/methyl acrylate 70:30 copolymer film deposited onto a glass surface and a water/nonionic surfactant/2-butanone (MEK) ternary system, with MEK being a good solvent and water being a nonsolvent for the polymer. Our results indicate a synergy between the organic solvent and the surfactant assemblies: MEK rapidly swells the outer layers of the polymer film allowing for the subsequent diffusion of solvent molecules, while the amphiphile decreases the interfacial energy between the polymeric coating and the liquid phase, favoring dewetting and dispersion of swollen polymer droplets in the aqueous phase. The chemical nature of the surfactant and the microstructure of the assemblies determine both the kinetics and the overall efficiency of polymer removal, as assessed by comparing the behavior of similar formulations containing an anionic surfactant (sodium dodecyl sulfate, SDS).

  16. Tandem Facial Amphiphiles for Membrane Protein Stabilization

    DEFF Research Database (Denmark)

    Chae, Pil Seok; Gotfryd, Kamil; Pacyna, Jennifer

    2010-01-01

    We describe a new type of synthetic amphiphile that is intended to support biochemical characterization of intrinsic membrane proteins. Members of this new family displayed favorable behavior with four of five membrane proteins tested, and these amphiphiles formed relatively small micelles....

  17. Mesoscale inhomogeneities in an aqueous ternary system

    Science.gov (United States)

    Subramanian, Deepa; Hayward, Stephen; Altabet, Elia; Collings, Peter; Anisimov, Mikhail

    2012-02-01

    Aqueous solutions of certain low-molecular-weight organic compounds, such as alcohols, amines, or ethers, which are considered macroscopically homogeneous, show the presence of mysterious mesoscale inhomogeneities, order of a hundred nm in size. We have performed static and dynamic light scattering experiments in an aqueous ternary system consisting of tertiary butyl alcohol and propylene oxide. Tertiary butyl alcohol is completely soluble in water and in propylene oxide, and forms strong hydrogen bonds with water molecules. Based on results of the study, we hypothesize that the mesoscale inhomogeneities are akin to a micro phase separation, resulting from a competition between water molecules and propylene oxide molecules, wanting to be adjacent to amphiphilic tertiary butyl alcohol molecules. Coupling between two competing order parameters, super-lattice binary-alloy-like (``antiferromagnetic'' type) and demixing (``ferromagnetic'' type) may explain the formation of these inhomogeneities. Long-term stability investigation of this supramolecular structure has revealed that these inhomogeneities are exceptionally long-lived non-equilibrium structures that persist for weeks or even months.

  18. Utilização do planejamento experimental no estudo do efeito da composição de misturas de bentonitas na reologia de fluidos de perfuração. Parte II: composições ternárias Experimental design applied to the study of composition effect of bentonite on the rheology of drilling fluids. Part II: ternary compositions

    Directory of Open Access Journals (Sweden)

    L. F. A. Campos

    2007-03-01

    Full Text Available O objetivo deste trabalho foi utilizar o planejamento experimental para avaliar o efeito da composição de misturas ternárias de bentonitas na reologia de fluidos de perfuração de poços de petróleo. Por meio do planejamento foram determinadas as proporções dos componentes nas misturas ternárias das argilas e então ajustados modelos de regressão relacionando viscosidade aparente, viscosidade plástica e volume de filtrado com a proporção de cada argila. A aplicação da modelagem de misturas, incluindo composições ternárias, aliada a metodologia de superfícies de resposta e otimização matemática e gráfica permitiu delimitar uma gama de composições de argilas que favorece a melhoria das propriedades reológicas e de filtração dos fluidos estudados.The purpose of this work was to study of composition effect of ternary bentonite mixtures on the rheology of drilling fluids. Through the experimental design were defined the components proportions in the ternary clays mixtures and then adjusted regression models relating apparent and plastic viscosities and water loss, with the proportion of each clay. The application of mixture experimental design, include ternary composition, response surface methodology, graphic and mathematical optimization allowed to delimit a strip of compositions that favors the improvement of the rheological properties of the drilling fluids.

  19. Approximately Ternary Homomorphisms on C*-Ternary Algebras

    Directory of Open Access Journals (Sweden)

    Eon Wha Shim

    2013-01-01

    functional equation: fx2-x1/3+fx1-3x3/3+f3x1+3x3-x2/3=fx1, by the direct method. Under the conditions in the main theorems, we can show that the related mappings must be zero. In this paper, we correct the conditions and prove the corrected theorems. Furthermore, we prove the Hyers-Ulam stability and the superstability of C*-ternary homomorphisms and C*-ternary derivations on C*-ternary algebras by using a fixed point approach.

  20. Peptide amphiphile self-assembly

    Science.gov (United States)

    Iscen, Aysenur; Schatz, George C.

    2017-08-01

    Self-assembly is a process whereby molecules organize into structures with hierarchical order and complexity, often leading to functional materials. Biomolecules such as peptides, lipids and DNA are frequently involved in self-assembly, and this leads to materials of interest for a wide variety of applications in biomedicine, photonics, electronics, mechanics, etc. The diversity of structures and functions that can be produced provides motivation for developing theoretical models that can be used for a molecular-level description of these materials. Here we overview recently developed computational methods for modeling the self-assembly of peptide amphiphiles (PA) into supramolecular structures that form cylindrical nanoscale fibers using molecular-dynamics simulations. Both all-atom and coarse-grained force field methods are described, and we emphasize how these calculations contribute insight into fiber structure, including the importance of β-sheet formation. We show that the temperature at which self-assembly takes place affects the conformations of PA chains, resulting in cylindrical nanofibers with higher β-sheet content as temperature increases. We also present a new high-density PA model that shows long network formation of β-sheets along the long axis of the fiber, a result that correlates with some experiments. The β-sheet network is mostly helical in nature which helps to maintain strong interactions between the PAs both radially and longitudinally. Contribution to Focus Issue Self-assemblies of Inorganic and Organic Nanomaterials edited by Marie-Paule Pileni.

  1. Marine amphiphilic siderophores: marinobactin structure, uptake, and microbial partitioning1

    OpenAIRE

    Martinez, Jennifer S.; Butler, Alison

    2007-01-01

    Marinobactins A-E are a suite of amphiphilic siderophores which have a common peptidic head group that coordinates Fe(III), and a fatty acid which varies in length and saturation. As a result of the amphiphilic properties of these siderophores it is difficult to study siderophore-mediated uptake of iron, because the amphiphilic siderophores partition indiscriminately in microbial and other membranes. An alternative method to distinguish amphiphilic siderophore partitioning versus siderophore-...

  2. Crystallization of Amphiphilic DNA C-Stars.

    Science.gov (United States)

    Brady, Ryan A; Brooks, Nicholas J; Cicuta, Pietro; Di Michele, Lorenzo

    2017-05-10

    Many emerging technologies require materials with well-defined three-dimensional nanoscale architectures. Production of these structures is currently underpinned by self-assembling amphiphilic macromolecules or engineered all-DNA building blocks. Both of these approaches produce restricted ranges of crystal geometries due to synthetic amphiphiles' simple shape and limited specificity, or the technical difficulties in designing space-filling DNA motifs with targeted shapes. We have overcome these limitations with amphiphilic DNA nanostructures, or "C-Stars", that combine the design freedom and facile functionalization of DNA-based materials with robust hydrophobic interactions. C-Stars self-assemble into single crystals exceeding 40 μm in size with lattice parameters exceeding 20 nm.

  3. Amphiphilic Alginates for Marine Antifouling Applications.

    Science.gov (United States)

    Jakobi, Victoria; Schwarze, Jana; Finlay, John A; Nolte, Kim A; Spöllmann, Stephan; Becker, Hans-Werner; Clare, Anthony S; Rosenhahn, Axel

    2018-02-12

    Amphiphilic polymers are promising candidates for novel fouling-release coatings for marine applications. We grafted amphiphilic alginates with fluorinated side chains to glass and silicon substrates and characterized the obtained films by contact angle goniometry, spectroscopic ellipsometry, XPS, and ATR-FTIR. The potential to inhibit protein attachment was tested against four different proteins, and intermediate fluorine loadings showed the strongest reduction with respect to hydrophobic, aliphatic controls. A similar trend was observed in dynamic attachment experiments using Navicula perminuta diatoms and settlement experiments with zoospores of the green algae Ulva linza. The results indicate that amphiphilic alginates are promising natural and renewable biomacromolecules that could be included in future protective coating technologies.

  4. Novel Tripod Amphiphiles for Membrane Protein Analysis

    DEFF Research Database (Denmark)

    Chae, Pil Seok; Kruse, Andrew C; Gotfryd, Kamil

    2013-01-01

    Integral membrane proteins play central roles in controlling the flow of information and molecules across membranes. Our understanding of membrane protein structures and functions, however, is seriously limited, mainly due to difficulties in handling and analysing these proteins in aqueous solution....... The use of a detergent or other amphipathic agents is required to overcome the intrinsic incompatibility between the large lipophilic surfaces displayed by the membrane proteins in their native forms and the polar solvent molecules. Here, we introduce new tripod amphiphiles displaying favourable...... behaviours toward several membrane protein systems, leading to an enhanced protein solubilisation and stabilisation compared to both conventional detergents and previously described tripod amphiphiles....

  5. Self-Assembly and Hydrogelation of Peptide Amphiphiles

    Directory of Open Access Journals (Sweden)

    Wahyudi Priyono Suwarso

    2012-04-01

    Full Text Available Seven peptide amphiphiles were successfully synthesized using solid phase peptide synthesis method. Peptide amphiphiles were characterized using matrix assisted laser desorption/ionization (MALDI. Atomic force microscopy (AFM study showed that peptide amphiphiles having glycine, valine, or proline as linker, self-assembled into 100-200 nm nanofibers structure. According to our research, both peptide amphiphile with positive and negative charges bear similar self-assembly properties. Peptide amphiphile also showed its capability as low molecular weight gelator (LMWG. Peptide amphiphiles bearing C-16 and C-12 as alkyl showed better hydrogelation properties than C-8 alkyl. Five out of seven peptide amphiphiles have minimum gelation concentration (MGC lower than 1% (w/v.

  6. Data transmission is faster with ternary coding

    CERN Document Server

    Bruins, T

    1974-01-01

    Discusses a ternary data transmission system for an effective rate of up to 6 megabits per second over a 1-mile line of ordinary twisted- pair cable. The methods are discussed of implementing a ternary data transmission system. (0 refs).

  7. Spontaneous formation of nanometer scale tubular vesicles in aqueous mixtures of lipid and block copolymer amphiphiles.

    Science.gov (United States)

    Lim, Seng Koon; Wong, Andrew S W; de Hoog, Hans-Peter M; Rangamani, Padmini; Parikh, Atul N; Nallani, Madhavan; Sandin, Sara; Liedberg, Bo

    2017-02-08

    Many common amphiphiles self-assemble in water to produce heterogeneous populations of discrete and symmetric but polydisperse and multilamellar vesicles isolating the encapsulated aqueous core from the surrounding bulk. But when mixtures of amphiphiles of vastly different elastic properties co-assemble, their non-uniform molecular organization can stabilize lower symmetries and produce novel shapes. Here, using high resolution electron cryomicroscopy and tomography, we identify the spontaneous formation of a membrane morphology consisting of unilamellar tubular vesicles in dilute aqueous solutions of binary mixtures of two different amphiphiles of vastly different origins. Our results show that aqueous phase mixtures of a fluid-phase phospholipid and an amphiphilic block copolymer spontaneously assume a bimodal polymorphic character in a composition dependent manner: over a broad range of compositions (15-85 mol% polymer component), a tubular morphology co-exists with spherical vesicles. Strikingly, in the vicinity of equimolar compositions, an exclusively tubular morphology (Lt; diameter, ∼15 nm; length, >1 μm; core, ∼2.0 nm; wall, ∼5-6 nm) emerges in an apparent steady state. Theory suggests that the spontaneous stabilization of cylindrical vesicles, unaided by extraneous forces, requires a significant spontaneous bilayer curvature, which in turn necessitates a strongly asymmetric membrane composition. We confirm that such dramatic compositional asymmetry is indeed produced spontaneously in aqueous mixtures of a lipid and polymer through two independent biochemical assays - (1) reduction in the quenching of fluorophore-labeled lipids and (2) inhibition in the activity of externally added lipid-hydrolyzing phospholipase A2, resulting in a significant enrichment of the polymer component in the outer leaflet. Taken together, these results illustrate the coupling of the membrane shape with local composition through spontaneous curvature generation under

  8. Amphiphilic lipids in solution: a simulational study of lipid bilayer formation

    Science.gov (United States)

    Vogel, Thomas; Landau, David P.; Gai, Lili; Maerzke, Katie A.; Iacovella, Christopher R.; McCabe, Clare M.; Cummings, Peter T.

    2013-03-01

    Amphiphilic molecules consisting of hydrophilic head and hydrophobic tail groups self-assemble into a wide variety of structures, such as bilayers (membranes), micelles, or vesicles (liposomes) when mixed with a suitable solvent. The understanding of this lipid self-assembly is essential for industrial, biological, or medical applications, but computer simulations are generally challenging due to the complex structure of the energy landscape. We show results for the lipid bilayer formation process obtained by newly developed parallel Wang-Landau Monte Carlo and statistical temperature molecular dynamics simulations. By applying those methods to a generic coarse-grained model for amphiphilic molecules in solution, we were able to obtain the thermodynamical data over the whole relevant temperature and energy range and to unravel the membrane formation process including all structural sub-transitions between different fluid and gel-phase bilayers. Research supported by NSF

  9. Thermodynamic and structural characterization of amphiphilic melamine-type monolayers.

    Science.gov (United States)

    Vollhardt, D; Fainerman, V B; Liu, F

    2005-06-16

    Monolayers of amphiphilic melamine derivatives are good candidates for the formation of supramolecular structures by hydrogen-bonding of nonsurface active species dissolved in the aqueous subphase by molecular recognition. In the present work, the thermodynamic and structural properties of the Langmuir monolayers of a homologous series of a selected amphiphilic melamine-type are characterized. Good candidates for such studies are the decyl, undecyl, and dodecyl homologues of the 2,4-di(n-alkylamino)-6-amino-1,3,5-triazine (2CnH(2n+1)-melamine) monolayers because of their two-phase coexistence region in the accessible temperature range. The characterization of the structural and phase behavior is performed by a combination of surface pressure studies with Brewster angle microscopy (BAM) imaging and Grazing incidence X-ray diffraction (GIXD) measurements. A comprehensive thermodynamic analysis provides good agreement between the experimental surface pressure - area (Pi-A) isotherms and the theoretical curves that were calculated on the basis of equations of state for a large region of monolayer stages developed by us in J. Phys. Chem. 1999, 103, 145. Theoretical curves calculated by application of equations of state only for the fluid monolayer state proposed recently by Rusanov (J. Chem Phys. 2004, 120, 10736) are in good agreement with the experiments in a limited temperature range. A rigorous equation is derived and applied to the experimental results for the calculation of the enthalpy of two-dimensional phase transition. The combination of BAM and GIXD illustrates that the microscopic long range ordering of the condensed monolayer phases is related to the lattice structure of the condensed monolayer.

  10. Solubility of amphiphiles in membranes: influence of phase properties and amphiphile head group.

    Science.gov (United States)

    Estronca, Luís M B B; Moreno, Maria João; Abreu, Magda S C; Melo, Eurico; Vaz, Winchil L C

    2002-08-23

    The solubilities of two fluorescent lipid amphiphiles with comparable apolar structures and different polar head groups, NBD-hexadecylamine and RG-tetradecylamine (or -octadecylamine), were compared in lipid bilayers at a molar ratio of 1/50 at 23 degrees C. Bilayers examined were in the solid, liquid-disordered, or liquid-ordered phases. While NBD-hexadecylamine was soluble in all the examined bilayer membrane phases, RG-tetradecylamine was stably soluble only in the liquid-disordered phase. RG-tetradecylamine insolubility in solid and liquid-ordered phases manifests itself as an aggregation of the amphiphile over a period of several days and the kinetics of aggregation were studied. Solubility of these amphiphiles in the different phases examined seems to be related to the dipole moment of the amphiphile (in particular, of the polar fluorophore) and its orientation relative to the dipolar potential of the membrane. We propose that amphiphilic molecules inserted into membranes (including lipid-attached proteins) partition into different coexisting membrane phases based upon: (1) nature of the apolar structure (chain length, degree of saturation, and chain branching as has been proposed in the literature); (2) magnitude and orientation of the dipole moment of the polar portion of the molecules relative to the membrane dipolar potential; and (3) hydration forces that are a consequence of ordering of water dipoles at the membrane surface.

  11. A Peptide Amphiphile Organogelator of Polar Organic Solvents

    Science.gov (United States)

    Rouse, Charlotte K.; Martin, Adam D.; Easton, Christopher J.; Thordarson, Pall

    2017-03-01

    A peptide amphiphile is reported, that gelates a range of polar organic solvents including acetonitrile/water, N,N-dimethylformamide and acetone, in a process dictated by β-sheet interactions and facilitated by the presence of an alkyl chain. Similarities with previously reported peptide amphiphile hydrogelators indicate analogous underlying mechanisms of gelation and structure-property relationships, suggesting that peptide amphiphile organogel design may be predictably based on hydrogel precedents.

  12. Liposomal Formulation of Amphiphilic Fullerene Antioxidants

    Science.gov (United States)

    Zhou, Zhiguo; Lenk, Robert P.; Dellinger, Anthony; Wilson, Stephen R.; Sadler, Robert; Kepley, Christopher L.

    2010-01-01

    Novel amphiphilic fullerene[70] derivatives that are rationally designed to intercalate in lipid bilayers are reported, as well as its vesicular formulation with surprisingly high loading capacity up to 65% by weight. The amphiphilic C70 bisadduct forms uniform and dimensionally stable liposomes with auxiliary natural phospholipids as demonstrated by buoyant density test, particle size distribution and 31P NMR. The antioxidant property of fullerenes is retained in the bipolarly functionalized C70 derivative, Amphiphilic Liposomal Malonylfullerene[70] (ALM) as well as in its liposomal formulations, as shown by both electron paramagnetic resonance (EPR) studies and in vitro reactive oxygen species (ROS) inhibition experiments. The liposomally formulated ALM efficiently quenched hydroxyl radicals and superoxide radicals. In addition, the fullerene liposome inhibited radical-induced lipid peroxidation and maintained the integrity of the lipid bilayer structure. This new class of liposomally formulated, amphipathic fullerene compounds represents a novel drug delivery system for fullerenes and provides a promising pathway to treat oxidative stress-related diseases. PMID:20839887

  13. Antibacterial activities of dendritic amphiphiles against nontuberculous mycobacteria.

    Science.gov (United States)

    Falkinham, Joseph O; Macri, Richard V; Maisuria, Bhadreshkumar B; Actis, Marcelo L; Sugandhi, Eko W; Williams, André A; Snyder, Alyson V; Jackson, Faunice R; Poppe, Michael A; Chen, Liang; Ganesh, Krithika; Gandour, Richard D

    2012-03-01

    The anti-mycobacterial activities of nine series of dicarboxyl and tricarboxyl dendritic amphiphiles with one alkyl, two alkyl, and cholestanyl tails against Mycobacterium abscessus, Mycobacterium avium, Mycobacterium chelonae, Mycobacterium marinum and Mycobacterium smegmatis have been measured. The dendritic amphiphiles overcame the limited aqueous solubility of natural long-chain fatty acids, alcohols, and amines to enable profiling the susceptibilities of the different mycobacterial species to the physicochemical properties of these amphiphiles. Several dendritic amphiphiles showed strong anti-mycobacterial activity with high critical micelle concentrations and low hemolytic activities thereby offering platforms for the development of antibiotics of higher activity against nontuberculous mycobacteria. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. Some new ternary linear codes

    Directory of Open Access Journals (Sweden)

    Rumen Daskalov

    2017-07-01

    Full Text Available Let an $[n,k,d]_q$ code be a linear code of length $n$, dimension $k$ and minimum Hamming distance $d$ over $GF(q$. One of the most important problems in coding theory is to construct codes with optimal minimum distances. In this paper 22 new ternary linear codes are presented. Two of them are optimal. All new codes improve the respective lower bounds in [11].

  15. Nearly Ternary Quadratic Higher Derivations on Non-Archimedean Ternary Banach Algebras: A Fixed Point Approach

    Directory of Open Access Journals (Sweden)

    M. Eshaghi Gordji

    2011-01-01

    Full Text Available We investigate the stability and superstability of ternary quadratic higher derivations in non-Archimedean ternary algebras by using a version of fixed point theorem via quadratic functional equation.

  16. Fluctuations and structure of amphiphilic films; Fluctuations et structure de films d`amphiphiles

    Energy Technology Data Exchange (ETDEWEB)

    Gourier, CH

    1996-07-01

    This thesis is divided in three parts.The first part exposes in a theoretical point of view, how the fluctuations spectrum of an amphiphilic film is governed by its properties and its bidimensional characteristics.The measurements of fluctuations spectra of an interface are accessible with the measurement of intensity that interface diffuses out of the specular angle, we present in the second chapter the principles of the X rays diffusion by a real interface and see how the diffuse diffusion experiments allow to determine the fluctuations spectrum of an amphiphilic film. The second part is devoted to the different experimental techniques that have allowed to realize the study of fluctuation as well as the structural study.The third part is devoted to experimental results concerning the measurements of fluctuations spectra and to the study of the structure of amphiphilic films. We show that it is possible by using an intense source of X rays (ESRF: European Synchrotron Radiation Facility) to measure the water and amphiphilic films fluctuations spectra until molecular scales. The last chapter is devoted to the structural study and film fluctuations made of di-acetylenic molecules. (N.C.)

  17. Biorelevant dissolution media: aggregation of amphiphiles and solubility of estradiol.

    Science.gov (United States)

    Ilardia-Arana, David; Kristensen, Henning G; Müllertz, Anette

    2006-02-01

    Biorelevant dissolution media containing bile salt and lecithin at concentrations appropriate for fed and fasted state are useful when testing oral solid formulations of poorly water-soluble drugs. Dilution of amphiphile solutions affects the aggregation state of the amphiphiles because bile salt is partitioned between the aqueous phase and the aggregates. The aim of the investigation was to study the effect of dilution on the size distribution of aggregates and its effect on the solubilization capacity. Clear buffered solutions of four intestinal amphiphiles (sodium glycocholate, lecithin, monoolein, and oleic acid) and a combination of these were prepared at high bile salt concentration. Micelles in the glycocholate solutions decreased in size when diluted. The addition of insoluble amphiphiles led to bigger micelles with no clear correlation between size of the micelles and amphiphile concentration. Dilution of the two- and four component media caused enlargement of the mixed micelles and formation of vesicles. The solubility of estradiol in the buffer solution was increased with addition of the amphiphiles. A good correlation (R(2) = 0.987) was found between estradiol solubility and mass concentration of the amphiphiles. The results demonstrate that, in the case of estradiol, the concentration of amphiphiles rather than the aggregation state determines the solubilization capacity of the medium. Copright 2005 Wiley-Liss, Inc.

  18. Multilayers of Fluorinated Amphiphilic Polyions for Marine Fouling Prevention

    NARCIS (Netherlands)

    Zhu, X.; Guo, S.; Janczewski, D.; Parra-Velandia, F.J.; Teo, S.L-M.; Vancso, Gyula J.

    2014-01-01

    Sequential layer-by-layer (LbL) deposition of polyelectrolytes followed by chemical cross-linking was investigated as a method to fabricate functional amphiphilic surfaces for marine biofouling prevention applications. A novel polyanion, grafted with amphiphilic perfluoroalkyl polyethylene glycol

  19. Glucose-neopentyl glycol (GNG) amphiphiles for membrane protein study

    DEFF Research Database (Denmark)

    Chae, Pil Seok; Rana, Rohini R; Gotfryd, Kamil

    2013-01-01

    The development of a new class of surfactants for membrane protein manipulation, "GNG amphiphiles", is reported. These amphiphiles display promising behavior for membrane proteins, as demonstrated recently by the high resolution structure of a sodium-pumping pyrophosphatase reported by Kellosalo et...

  20. On Some Ternary LCD Codes

    OpenAIRE

    Darkunde, Nitin S.; Patil, Arunkumar R.

    2018-01-01

    The main aim of this paper is to study $LCD$ codes. Linear code with complementary dual($LCD$) are those codes which have their intersection with their dual code as $\\{0\\}$. In this paper we will give rather alternative proof of Massey's theorem\\cite{8}, which is one of the most important characterization of $LCD$ codes. Let $LCD[n,k]_3$ denote the maximum of possible values of $d$ among $[n,k,d]$ ternary $LCD$ codes. In \\cite{4}, authors have given upper bound on $LCD[n,k]_2$ and extended th...

  1. Superconducting state parameters of ternary metallic glasses

    Indian Academy of Sciences (India)

    Administrator

    pseudopotential to ternary metallic glasses involves the assumption of pseudoions with average properties, which are assumed to replace three types of ions in the ternary systems, and a gas of free electrons is assumed to perme- ate through them. The electron–pseudoion is accounted by the pseudopotential, and the ...

  2. Ternary rhythm and the lapse constraint

    NARCIS (Netherlands)

    Elenbaas, N.; Kager, R.W.J.

    2004-01-01

    Ternary rhythmic systems differ from binary systems in stressing every third syllable in a word, rather than every second. Ternary rhythm is well-established for only a small group of languages, including Chugach Alutiiq, Cayuvava, and Estonian, and possibly Winnebago. Nevertheless the stress

  3. The prediction of amphiphilic alpha-helices.

    Science.gov (United States)

    Phoenix, D A; Harris, F; Daman, O A; Wallace, J

    2002-04-01

    A number of sequence-based analyses have been developed to identify protein segments, which are able to form membrane interactive amphiphilic alpha-helices. Earlier techniques attempted to detect the characteristic periodicity in hydrophobic amino acid residues shown by these structure and included the Molecular Hydrophobic Potential (MHP), which represents the hydrophobicity of amino acid residues as lines of isopotential around the alpha-helix and analyses based on Fourier transforms. These latter analyses compare the periodicity of hydrophobic residues in a putative alpha-helical sequence with that of a test mathematical function to provide a measure of amphiphilicity using either the Amphipathic Index or the Hydrophobic Moment. More recently, the introduction of computational procedures based on techniques such as hydropathy analysis, homology modelling, multiple sequence alignments and neural networks has led to the prediction of transmembrane alpha-helices with accuracies of the order of 95% and transmembrane protein topology with accuracies greater than 75%. Statistical approaches to transmembrane protein modeling such as hidden Markov models have increased these prediction levels to an even higher level. Here, we review a number of these predictive techniques and consider problems associated with their use in the prediction of structure / function relationships, using alpha-helices from G-coupled protein receptors, penicillin binding proteins, apolipoproteins, peptide hormones, lytic peptides and tilted peptides as examples.

  4. High-Efficient Circuits for Ternary Addition

    Directory of Open Access Journals (Sweden)

    Reza Faghih Mirzaee

    2014-01-01

    Full Text Available New ternary adders, which are fundamental components of ternary addition, are presented in this paper. They are on the basis of a logic style which mostly generates binary signals. Therefore, static power dissipation reaches its minimum extent. Extensive different analyses are carried out to examine how efficient the new designs are. For instance, the ternary ripple adder constructed by the proposed ternary half and full adders consumes 2.33 μW less power than the one implemented by the previous adder cells. It is almost twice faster as well. Due to their unique superior characteristics for ternary circuitry, carbon nanotube field-effect transistors are used to form the novel circuits, which are entirely suitable for practical applications.

  5. Crystal Growth of Ternary Compound Semiconductors in Low Gravity Environment

    Science.gov (United States)

    Su, Ching-Hua

    2014-01-01

    A low gravity material experiment will be performed in the Material Science Research Rack (MSRR) on International Space Station (ISS). There are two sections of the flight experiment: (I) crystal growth of ZnSe and related ternary compounds, such as ZnSeS and ZnSeTe, by physical vapor transport (PVT) and (II) melt growth of CdZnTe by directional solidification. The main objective of the project is to determine the relative contributions of gravity-driven fluid flows to the compositional distribution, incorporation of impurities and defects, and deviation from stoichiometry observed in the grown crystals as results of buoyancy-driven convection and growth interface fluctuations caused by irregular fluid-flows on Earth. The investigation consists of extensive ground-based experimental and theoretical research efforts and concurrent flight experimentation. This talk will focus on the ground-based studies on the PVT crystal growth of ZnSe and related ternary compounds. The objectives of the ground-based studies are (1) obtain the experimental data and conduct the analyses required to define the optimum growth parameters for the flight experiments, (2) perfect various characterization techniques to establish the standard procedure for material characterization, (3) quantitatively establish the characteristics of the crystals grown on Earth as a basis for subsequent comparative evaluations of the crystals grown in a low-gravity environment and (4) develop theoretical and analytical methods required for such evaluations. ZnSe and related ternary compounds have been grown by vapor transport technique with real time in-situ non-invasive monitoring techniques. The grown crystals have been characterized extensively by various techniques to correlate the grown crystal properties with the growth conditions.

  6. Repurposing Cationic Amphiphilic Antihistamines for Cancer Treatment

    DEFF Research Database (Denmark)

    Ellegaard, Anne-Marie; Dehlendorff, Christian; Vind, Anna C.

    2016-01-01

    Non-small cell lung cancer (NSCLC) is one of the deadliest cancers worldwide. In search for new NSCLC treatment options, we screened a cationic amphiphilic drug (CAD) library for cytotoxicity against NSCLC cells and identified several CAD antihistamines as inducers of lysosomal cell death. We...... then performed a cohort study on the effect of CAD antihistamine use on mortality of patients diagnosed with non-localized cancer in Denmark between 1995 and 2011. The use of the most commonly prescribed CAD antihistamine, loratadine, was associated with significantly reduced all-cause mortality among patients...... with non-localized NSCLC or any non-localized cancer when compared with use of non-CAD antihistamines and adjusted for potential confounders. Of the less frequently described CAD antihistamines, astemizole showed a similar significant association with reduced mortality as loratadine among patients with any...

  7. Performance Estimation for Lowpass Ternary Filters

    Directory of Open Access Journals (Sweden)

    Brenton Steele

    2003-11-01

    Full Text Available Ternary filters have tap values limited to −1, 0, or +1. This restriction in tap values greatly simplifies the multipliers required by the filter, making ternary filters very well suited to hardware implementations. Because they incorporate coarse quantisation, their performance is typically limited by tap quantisation error. This paper derives formulae for estimating the achievable performance of lowpass ternary filters, thereby allowing the number of computationally intensive design iterations to be reduced. Motivated by practical communications systems requirements, the performance measure which is used is the worst-case stopband attenuation.

  8. Facially amphiphilic thiol capped gold and silver nanoparticles

    Indian Academy of Sciences (India)

    Abstract. A series of bile acid-derived facially amphiphilic thiols have been used to cap sliver and gold nanoparticles. The self-assembling properties of these steroid-capped nanoparticles have been investigated and reported in this article.

  9. Marine amphiphilic siderophores: marinobactin structure, uptake, and microbial partitioning.

    Science.gov (United States)

    Martinez, Jennifer S; Butler, Alison

    2007-11-01

    Marinobactins A-E are a suite of amphiphilic siderophores which have a common peptidic head group that coordinates Fe(III), and a fatty acid which varies in length and saturation. As a result of the amphiphilic properties of these siderophores it is difficult to study siderophore-mediated uptake of iron, because the amphiphilic siderophores partition indiscriminately in microbial and other membranes. An alternative method to distinguish amphiphilic siderophore partitioning versus siderophore-mediated active uptake for Fe(III)-marinobactin E has been developed. In addition, a new member of the marinobactin family of siderophores is also reported, marinobactin F, which has a C(18) fatty acid with one double bond and which is substantially more hydrophobic that marinobactins A-E.

  10. Ternary networks reliability and Monte Carlo

    CERN Document Server

    Gertsbakh, Ilya; Vaisman, Radislav

    2014-01-01

    Ternary means “based on three”. This book deals with reliability investigations of  networks whose components subject to failures can be in three states –up, down and middle (mid), contrary to traditionally considered networks  having only binary (up/down) components. Extending binary case to ternary allows to consider more realistic and flexible models for communication, flow and supply networks.

  11. Synthesis of ternary nitrides by mechanochemical alloying

    DEFF Research Database (Denmark)

    Jacobsen, C.J.H.; Zhu, J.J.; Lindelov, H.

    2002-01-01

    Ternary metal nitrides ( of general formula MxM'N-y(z)) attract considerable interest because of their special mechanical, electrical, magnetic, and catalytic properties. Usually they are prepared by ammonolysis of ternary oxides (MxM'O-y(m)) at elevated temperatures. We show that ternary...... nitrides by mechanochemical alloying of a binary transition metal nitride (MxN) with an elemental transition metal. In this way, we have been able to prepare Fe3Mo3N and Co3Mo3N by ball-milling of Mo2N with Fe and Co, respectively. The transformation sequence from the starting materials ( the binary...... nitride and the transition metal) to the ternary nitride was followed by Mossbauer spectroscopy (for Fe3Mo3N) and by X-ray powder diffraction ( for both Fe3Mo3N and Co3Mo3N). Usually, the preparation of a given ternary nitride by ammonolysis of a ternary oxide is dependent on the availability of an oxide...

  12. Antibacterial Activity of Geminized Amphiphilic Cationic Homopolymers.

    Science.gov (United States)

    Wang, Hui; Shi, Xuefeng; Yu, Danfeng; Zhang, Jian; Yang, Guang; Cui, Yingxian; Sun, Keji; Wang, Jinben; Yan, Haike

    2015-12-22

    The current study is aimed at investigating the effect of cationic charge density and hydrophobicity on the antibacterial and hemolytic activities. Two kinds of cationic surfmers, containing single or double hydrophobic tails (octyl chains or benzyl groups), and the corresponding homopolymers were synthesized. The antimicrobial activity of these candidate antibacterials was studied by microbial growth inhibition assays against Escherichia coli, and hemolysis activity was carried out using human red blood cells. It was interestingly found that the homopolymers were much more effective in antibacterial property than their corresponding monomers. Furthermore, the geminized homopolymers had significantly higher antibacterial activity than that of their counterparts but with single amphiphilic side chains in each repeated unit. Geminized homopolymers, with high positive charge density and moderate hydrophobicity (such as benzyl groups), combine both advantages of efficient antibacterial property and prominently high selectivity. To further explain the antibacterial performance of the novel polymer series, the molecular interaction mechanism is proposed according to experimental data which shows that these specimens are likely to kill microbes by disrupting bacterial membranes, leading them unlikely to induce resistance.

  13. Repurposing Cationic Amphiphilic Antihistamines for Cancer Treatment.

    Science.gov (United States)

    Ellegaard, Anne-Marie; Dehlendorff, Christian; Vind, Anna C; Anand, Atul; Cederkvist, Luise; Petersen, Nikolaj H T; Nylandsted, Jesper; Stenvang, Jan; Mellemgaard, Anders; Østerlind, Kell; Friis, Søren; Jäättelä, Marja

    2016-07-01

    Non-small cell lung cancer (NSCLC) is one of the deadliest cancers worldwide. In search for new NSCLC treatment options, we screened a cationic amphiphilic drug (CAD) library for cytotoxicity against NSCLC cells and identified several CAD antihistamines as inducers of lysosomal cell death. We then performed a cohort study on the effect of CAD antihistamine use on mortality of patients diagnosed with non-localized cancer in Denmark between 1995 and 2011. The use of the most commonly prescribed CAD antihistamine, loratadine, was associated with significantly reduced all-cause mortality among patients with non-localized NSCLC or any non-localized cancer when compared with use of non-CAD antihistamines and adjusted for potential confounders. Of the less frequently described CAD antihistamines, astemizole showed a similar significant association with reduced mortality as loratadine among patients with any non-localized cancer, and ebastine use showed a similar tendency. The association between CAD antihistamine use and reduced mortality was stronger among patients with records of concurrent chemotherapy than among those without such records. In line with this, sub-micromolar concentrations of loratadine, astemizole and ebastine sensitized NSCLC cells to chemotherapy and reverted multidrug resistance in NSCLC, breast and prostate cancer cells. Thus, CAD antihistamines may improve the efficacy of cancer chemotherapy. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  14. Interfacial adsorption and aggregation of amphiphilic proteins

    Science.gov (United States)

    Cheung, David

    2012-02-01

    The adsorption and aggregation on liquid interfaces of proteins is important in many biological contexts, such as the formation of aerial structures, immune response, and catalysis. Likewise the adsorption of proteins onto interfaces has applications in food technology, drug delivery, and in personal care products. As such there has been much interest in the study of a wide range of biomolecules at liquid interfaces. One class of proteins that has attracted particular attention are hydrophobins, small, fungal proteins with a distinct, amphiphilic surface structure. This makes these proteins highly surface active and they recently attracted much interest. In order to understand their potential applications a microscopic description of their interfacial and self-assembly is necessary and molecular simulation provides a powerful tool for providing this. In this presentation I will describe some recent work using coarse-grained molecular dynamics simulations to study the interfacial and aggregation behaviour of hydrophobins. Specifically this will present the calculation of their adsorption strength at oil-water and air-water interfaces, investigate the stability of hydrophobin aggregates in solution and their interaction with surfactants.

  15. Growth Dynamics of Domains in Ternary Fluid Vesicles

    OpenAIRE

    Miho, Yanagisawa; Masayuki, Imai; Dept. of Physics, Ochanomizu Univ.; Dept. of Physics, Ochanomizu Univ.

    2006-01-01

    飽和リン脂質、不飽和リン脂質、コレステロールからなる3成分ベシクルにおける液体ドメインの成長ダイナミクスを蛍光顕微鏡観察した結果、Normal coarseningとTrapped coarseningに分けられた。Normal coarseningを示すベシクルは余剰面積をほぼ持たず、ドメインは2次元のスケーリング則t~D^2lnD(Dはドメインサイズ)に従ってBuddingせずに成長する。しかし成長の初期過程では流体力学的相互作用によるずれが生じる。一方、Trapped coarseningを示すベシクルは大きな余剰面積を持ち、ドメインはあるサイズまで成長するとBuddingしTrapされる。Buddingしたドメインが近づくと、ドメイン間に挟まれたマトリックスの曲げエネルギーが増大し、ドメインの合体を妨げる斥力を生む。Buddingしたドメインを持つベシクルの自由エネルギーの解析から、ベシクルの持つ余剰面積がある値よりも大きい時、余剰面積が大きい程コースニングのより初期課程でBuddingしTrapされることが分かり、実験結果を説明することが出来た。...

  16. Formation and antifouling properties of amphiphilic coatings on polypropylene fibers.

    Science.gov (United States)

    Goli, Kiran K; Rojas, Orlando J; Genzer, Jan

    2012-11-12

    We describe the formation of amphiphilic polymeric assemblies via a three-step functionalization process applied to polypropylene (PP) nonwovens and to reference hydrophobic self-assembled n-octadecyltrichlorosilane (ODTS) monolayer surfaces. In the first step, denatured proteins (lysozyme or fibrinogen) are adsorbed onto the hydrophobic PP or the ODTS surfaces, followed by cross-linking with glutaraldehyde in the presence of sodium borohydride (NaBH(4)). The hydroxyl and amine functional groups of the proteins permit the attachment of initiator molecules, from which poly (2-hydroxyethyl methacrylate) (PHEMA) polymer grafts are grown directly through "grafting from" atom transfer radical polymerization. The terminal hydroxyls of HEMA's pendent groups are modified with fluorinating moieties of different chain lengths, resulting in amphiphilic brushes. A palette of analytical tools, including ellipsometry, contact angle goniometry, Fourier transform infrared spectroscopy in the attenuated total reflection mode, and X-ray photoelectron spectroscopy is employed to determine the changes in physicochemical properties of the functionalized surfaces after each modification step. Antifouling properties of the resultant amphiphilic coatings on PP are analyzed by following the adsorption of fluorescein isothiocyanate-labeled bovine serum albumin as a model fouling protein. Our results suggest that amphiphilic coatings suppress significantly adsorption of proteins as compared with PP fibers or PP surfaces coated with PHEMA brushes. The type of fluorinated chain grafted to PHEMA allows modulation of the surface composition of the topmost layer of the amphiphilic coating and its antifouling capability.

  17. Amphiphilic chitosan derivatives as carrier agents for rotenone

    Science.gov (United States)

    Kamari, Azlan; Aljafree, Nurul Farhana Ahmad

    2017-08-01

    In the present study, the feasibility of amphiphilic chitosan derivatives, namely oleoyl carboxymethyl chitosan (OCMCs), N,N-dimethylhexadecyl carboxymethyl chitosan (DCMCs) and deoxycholic acid carboxymethyl chitosan (DACMCs) as carrier agents for rotenone in water-insoluble pesticide formulations was investigated. Fourier Transform Infrared (FTIR) Spectrometer, CHN-O Elemental Analyser (CHN-O) and Transmission Electron Microscope (TEM) were used to characterise amphiphilic chitosan derivatives. The critical micelle concentration (CMC) of amphiphilic chitosan derivatives was determined using a Fluorescence Spectrometer. A High Performance Liquid Chromatography (HPLC) was used to determine the ability of OCMCs, DCMCs and DACMCs to load and release rotenone in an in vitro system. Based on TEM analysis, results have shown that amphiphilic chitosan derivatives formed self-assembly and exhibited spherical shape. The CMC values determined for OCMCs, DCMCs and DACMCs were 0.093, 0.098 and 0.468 mg/mL, respectively. The encapsulation efficiency (EE) values for the materials were more than 97.0%, meanwhile the loading capacity (LC) values were greater than 0.90%. OCMCs, DCMCs and DACMCs micelles exhibited an excellent ability to control the release of rotenone, of which 90.0% of rotenone was released within 40 to 52 h. In conclusion, OCMCs, DCMCs and DACMCs possess several key features to act as effective carrier agents for rotenone. Overall, amphiphilic chitosan derivatives produced in this study were successfully increased the solubility of rotenone by 49.0 times higher than free rotenone.

  18. Rheological and phase behaviour of amphiphilic lipids

    Directory of Open Access Journals (Sweden)

    Alfaro, M. C.

    2000-04-01

    Full Text Available This chapter reviews the different association structures which are likely to be formed by amphiphilic lipids in the liquid-crystalline state and their corresponding shear flow properties. The structure and rheological behaviour of thermotropic liquid crystals, emphasizing the properties of smectic mesophases, and those of lyotropic liquid crystals such as: nematic, lamellar, diluted lamellar, lamellar dispersions, hexagonal and cubic mesophases are described. The importance of a comprehensive rheological characterisation, including rheo-optical techniques, is pointed out for their practical applications, development of formulations and as a useful technique to assist in the determination of phase diagrams. A historical approach has been used to discuss the evolving field of the rheology and structure identification of liquid crystals formed by amphiphilic lipids and surfactants. Non-Newtonian viscous shear flow, thixotropic and antithixotropic phenomena, linear viscoelastic properties -described by dynamic and creep compliance experiments- and non-linear viscoelastic properties - described by the difference of normal stresses and stress relaxation tests are interpreted on the basis of a microstructure-rheology relationship. The polycrystalline nature of liquid crystals turns out to be rather sensitive to shear due to the change of both size and orientation of the liquid-crystalline monodomains under flow.En este capítulo se realiza una revisión de las distintas estructuras coloidales de asociación que pueden formar los lípidos anfifílicos en estado líquido-cristalino y de sus correspondientes propiedades de flujo en cizalla. Se describe la estructura y comportamiento reológico de cristales líquidos termotrópicos, con énfasis en los de tipo esméctico, fases gel, y cristales líquidos liotrópicos: nemáticos, laminares, laminares diluidos, dispersiones de laminares, hexagonales y cúbicos. Se hace hincapié en la importancia de una

  19. Absorption fluids data survey: 1989 update

    Energy Technology Data Exchange (ETDEWEB)

    Macriss, R.A.; Zawacki, T.S. (Institute of Gas Technology, Chicago, IL (USA))

    1989-01-01

    This is an update of a series of prior reports on absorption fluids and data, ORNL/Sub/84-47989/1, 2, 3. It covers additional data developed and published mainly during 1985--88, and cites 44 additional references. Seventy-four different worldwide publications containing data relating to properties of binary, ternary, and multicomponent absorption fluids were identified. Of these, 30 manuscripts include applications of absorption fluid properties data toward evaluation, assessment, or design of chillers or heat pumps but do not include actual fluid properties data. The remaining 44 publications date as far back as 1929, but over 50% of these documents were published between 1985 and 1988. The texts of the 44 manuscripts are in English, German, Japanese, Russian, or French. The absorption fluids discussed in the 44 documents are combinations of 9 different refrigerant'' compounds and 30 single, 7 binary, and 1 ternary absorbent'' compounds. 44 refs., 21 tabs.

  20. HPMA based amphiphilic copolymers mediate central nervous effects of domperidone.

    Science.gov (United States)

    Hemmelmann, Mirjam; Knoth, Christiane; Schmitt, Ulrich; Allmeroth, Mareli; Moderegger, Dorothea; Barz, Matthias; Koynov, Kaloian; Hiemke, Christoph; Rösch, Frank; Zentel, Rudolf

    2011-05-18

    In this study we give evidence that domperidone encapsulated into amphiphilic p(HPMA)-co-p(laurylmethacrylate) (LMA) copolymer aggregates is able to cross the blood-brain barrier, since it affected motor behaviour in animals, which is a sensitive measure for CNS actions. Carefully designed copolymers based on the clinically approved p(HPMA) were selected and synthesized by a combination of controlled radical polymerization and post-polymerization modification. The hydrodynamic radii (R(h) ) of amphiphilic p(HPMA)-co-p(LMA) alone and loaded with domperidone were determined by fluorescence correlation spectroscopy. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Amphiphilic Polymer Platforms: Surface Engineering of Films for Marine Antibiofouling.

    Science.gov (United States)

    Galli, Giancarlo; Martinelli, Elisa

    2017-04-01

    A range of amphiphilic polymers with diverse macromolecular architectures has been developed and incorporated into films and coatings with potential for marine antibiofouling applications, without resorting to addition of currently used biocidal, toxic agents. Novel "green" chemical technologies employ different building blocks to endow the polymer film with surface activity, functionality, structure, and reconstruction according to the outer environment as a result of a tailored amphiphilic character of the polymer platform. We emphasise how these features can interplay and add synergistically to affect antifouling and fouling-release against common, widespread marine micro- and macro-fouling organisms. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Ternary interaction parameters in calphad solution models

    Energy Technology Data Exchange (ETDEWEB)

    Eleno, Luiz T.F., E-mail: luizeleno@usp.br [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Fisica; Schön, Claudio G., E-mail: schoen@usp.br [Universidade de Sao Paulo (USP), SP (Brazil). Computational Materials Science Laboratory. Department of Metallurgical and Materials Engineering

    2014-07-01

    For random, diluted, multicomponent solutions, the excess chemical potentials can be expanded in power series of the composition, with coefficients that are pressure- and temperature-dependent. For a binary system, this approach is equivalent to using polynomial truncated expansions, such as the Redlich-Kister series for describing integral thermodynamic quantities. For ternary systems, an equivalent expansion of the excess chemical potentials clearly justifies the inclusion of ternary interaction parameters, which arise naturally in the form of correction terms in higher-order power expansions. To demonstrate this, we carry out truncated polynomial expansions of the excess chemical potential up to the sixth power of the composition variables. (author)

  3. Ternary carbon composite films for supercapacitor applications

    Science.gov (United States)

    Tran, Minh-Hai; Jeong, Hae Kyung

    2017-09-01

    A simple, binder-free, method of making supercapacitor electrodes is introduced, based on modification of activated carbon with graphite oxide and carbon nanotubes. The three carbon precursors of different morphologies support each other to provide outstanding electrochemical performance, such as high capacitance and high energy density. The ternary carbon composite shows six times higher specific capacitance compared to that of activated carbon itself with high retention. The excellent electrochemical properties of the ternary composite attribute to the high surface area of 1933 m2 g-1 and low equivalent series resistance of 2 Ω, demonstrating that it improve the electrochemical performance for supercapacitor applications.

  4. A study of phase separation in ternary alloys

    Indian Academy of Sciences (India)

    Keywords. Ternary systems; Cahn–Hilliard equations; spinodal decomposition. Abstract. We have studied the evolution of microstructure when a disordered ternary alloy is quenched into a ternary miscibility gap. We have used computer simulations based on multicomponent Cahn–Hilliard (CH) equations for A and B, ...

  5. Ternary-fragmentation-driving potential energies of 252Cf

    Science.gov (United States)

    Karthikraj, C.; Ren, Zhongzhou

    2017-12-01

    Within the framework of a simple macroscopic model, the ternary-fragmentation-driving potential energies of 252Cf are studied. In this work, all possible ternary-fragment combinations of 252Cf are generated by the use of atomic mass evaluation-2016 (AME2016) data and these combinations are minimized by using a two-dimensional minimization approach. This minimization process can be done in two ways: (i) with respect to proton numbers (Z1, Z2, Z3) and (ii) with respect to neutron numbers (N1, N2, N3) of the ternary fragments. In this paper, the driving potential energies for the ternary breakup of 252Cf are presented for both the spherical and deformed as well as the proton-minimized and neutron-minimized ternary fragments. From the proton-minimized spherical ternary fragments, we have obtained different possible ternary configurations with a minimum driving potential, in particular, the experimental expectation of Sn + Ni + Ca ternary fragmentation. However, the neutron-minimized ternary fragments exhibit a driving potential minimum in the true-ternary-fission (TTF) region as well. Further, the Q -value energy systematics of the neutron-minimized ternary fragments show larger values for the TTF fragments. From this, we have concluded that the TTF region fragments with the least driving potential and high Q values have a strong possibility in the ternary fragmentation of 252Cf. Further, the role of ground-state deformations (β2, β3, β4, and β6) in the ternary breakup of 252Cf is also studied. The deformed ternary fragmentation, which involves Z3=12 -19 fragments, possesses the driving potential minimum due to the larger oblate deformations. We also found that the ground-state deformations, particularly β2, strongly influence the driving potential energies and play a major role in determining the most probable fragment combinations in the ternary breakup of 252Cf.

  6. Diffusion of surface-active amphiphiles in silicone-based fouling-release coatings

    DEFF Research Database (Denmark)

    Noguer, Albert Camós; Olsen, S. M.; Hvilsted, Søren

    2017-01-01

    Amphiphiles (i.e. amphiphilic molecules such as surfactants, block copolymers and similar compounds) are used in small amounts to modify the surface properties of polymeric materials. In silicone fouling-release coatings, PEG-based amphiphiles are added to provide biofouling-resistance. The success...... of this approach relies on the ability of the amphiphiles to diffuse through the coating film and cover the surface of the coating. A novel method for the measurement of diffusion coefficients of PEG-based amphiphiles of different chemistries in PDMS-based coatings is presented here. The diffusion coefficient...... of the amphiphiles shows a weak dependency on their molecular weight, although this dependency is much less pronounced than for other rubbery polymeric materials. The biofouling-resistance properties in fouling-release coatings were also studied for these amphiphiles. It was found that the diffusion coefficient does...

  7. Self-triggered coordination with ternary controllers

    NARCIS (Netherlands)

    De Persis, Claudio; Frasca, Paolo

    2012-01-01

    This paper regards coordination of networked systems with ternary controllers. We develop a hybrid coordination system which implements a self-triggered communication policy, based on polling the neighbors upon need. We prove that the proposed scheme ensures finite-time convergence to a neighborhood

  8. Ternary Dynamic Images In Robotic Smooth Pursuit

    Science.gov (United States)

    Morasso, Pietro; Tagliasco, Vincenzo

    1984-02-01

    Early stages of visuo-motor interaction are considered with regard to dynamic scene analysis. Target fixation and tracking is distinguished from target visual analysis. The notion of target specification is elaborated upon. The use of ternary dynamic images is shown as an example of target tracking.

  9. Ternary alloy nanocatalysts for hydrogen evolution reaction

    Indian Academy of Sciences (India)

    Ternary alloy nanocatalysts for hydrogen evolution reaction. SOUMEN SAHA1, SONALIKA VAIDYA2, KANDALAM V RAMANUJACHARY3,. SAMUEL E LOFLAND4 and ASHOK K GANGULI1,2,∗. 1Department of Chemistry, Indian Institute of Technology, Hauz Khas, New Delhi 110016, India. 2Institute of Nano Science and ...

  10. Blends of Amphiphilic, Hyperbranched Polyesters and Different Polyolefins

    NARCIS (Netherlands)

    Schmaljohann, D.; Pötschke, P.; Hässler, R.; Voit, B.I.; Froehling, P.E.; Mostert, B.; Loontjens, J.A.

    1999-01-01

    A hyperbranched polyester based on 3,5-dihydroxybenzoic acid was completely modified with dodecanoyl chloride to result in an amphiphilic, globular polymer, which has a polar core and a nonpolar outer sphere with the ability both to incorporate an organic dye and to interact with a nonpolar matrix.

  11. Water-Soluble Gold Nanoparticles Protected by Fluorinated Amphiphilic Thiolates

    NARCIS (Netherlands)

    Gentilini, Cristina; Evangelista, Fabrizio; Rudolf, Petra; Franchi, Paola; Lucarini, Marco; Pasquato, Lucia

    2008-01-01

    The preparation and the properties of gold nanoparticles (Au NPs) protected by perfluorinated amphiphiles are described. The thiols were devised to form a perfluorinated region close to the gold surface and to have a hydrophilic portion in contact with the bulk solvent to impart solubility in water.

  12. Detection of Lipid and Amphiphilic Biomarkers for Disease Diagnostics.

    Science.gov (United States)

    Kubicek-Sutherland, Jessica Z; Vu, Dung M; Mendez, Heather M; Jakhar, Shailja; Mukundan, Harshini

    2017-07-04

    Rapid diagnosis is crucial to effectively treating any disease. Biological markers, or biomarkers, have been widely used to diagnose a variety of infectious and non-infectious diseases. The detection of biomarkers in patient samples can also provide valuable information regarding progression and prognosis. Interestingly, many such biomarkers are composed of lipids, and are amphiphilic in biochemistry, which leads them to be often sequestered by host carriers. Such sequestration enhances the difficulty of developing sensitive and accurate sensors for these targets. Many of the physiologically relevant molecules involved in pathogenesis and disease are indeed amphiphilic. This chemical property is likely essential for their biological function, but also makes them challenging to detect and quantify in vitro. In order to understand pathogenesis and disease progression while developing effective diagnostics, it is important to account for the biochemistry of lipid and amphiphilic biomarkers when creating novel techniques for the quantitative measurement of these targets. Here, we review techniques and methods used to detect lipid and amphiphilic biomarkers associated with disease, as well as their feasibility for use as diagnostic targets, highlighting the significance of their biochemical properties in the design and execution of laboratory and diagnostic strategies. The biochemistry of biological molecules is clearly relevant to their physiological function, and calling out the need for consideration of this feature in their study, and use as vaccine, diagnostic and therapeutic targets is the overarching motivation for this review.

  13. Micellar structure of amphiphilic poly(2-oxazoline) diblock copolymers

    DEFF Research Database (Denmark)

    Papadakis, C.M.; Ivanova, R.; Lüdtke, K.

    2007-01-01

    Amphiphilic diblock copolymers from poly(2-oxazoline)s in aqueous solution can form micelles. By means of small-angle neutron scattering, we have found that poly[(n-nonyl-2-oxazoline)-b-(methyl-2-oxazoline)] {P[(NOx)-b-(MOx)]} diblock copolymers in aqueous solution form micelles of core-shell typ...

  14. Fluorescence sensing of spermine with a frustrated amphiphile.

    Science.gov (United States)

    Köstereli, Ziya; Severin, Kay

    2012-06-14

    A charge-frustrated amphiphile composed of a pyrene-1,3,6-trisulfonate head group and an eicosane side chain can be used as a fluorescence chemosensor for spermine. The sensor allows the detection of spermine down to the nanomolar concentration range with good selectivity over closely related biogenic amines such as spermidine.

  15. Biosynthesis of an amphiphilic silk-like polymer

    NARCIS (Netherlands)

    Werten, M.W.T.; Moers, A.P.H.A.; Vong, T.H.; Zuilhof, H.; Hest, van J.C.M.; Wolf, de F.A.

    2008-01-01

    An amphiphilic silk-like protein polymer was efficiently produced in the yeast Pichia pastoris. The secreted product was fully intact and was purified by solubilization in formic acid and subsequent precipitation of denatured host proteins upon dilution with water. In aqueous alkaline solution, the

  16. On the slowdown mechanism of water dynamics around small amphiphiles

    NARCIS (Netherlands)

    Homsi Brandeburgo, W.; Thijmen van der Post, S.; Meijer, E.J.; Ensing, B.

    2015-01-01

    Aqueous solvation of small amphiphilic molecules exhibits a unique and complex dynamics, that is only partially understood. A recent series of studies on the hydration of small organic compounds, such as tetramethylurea (TMU), trimethylamine N-oxide (TMAO) and urea, has provided strong evidence of a

  17. Nucleic acid amphiphiles : synthesis and self-assembled nanostructures

    NARCIS (Netherlands)

    Kwak, Minseok; Herrmann, Andreas; Clever, Guido; Mao, Chengde; Shionoya, Mitsuhiko; Stulz, Eugen

    2011-01-01

    This review provides an overview of a relatively new class of bio-conjugates, DNA amphiphiles, which consist of oligonucleotides covalently bonded to synthetic hydrophobic units. The reader will find the basic principles for the structural design and preparation methods of the materials. Moreover,

  18. Ammonium amphiphiles carrying mesogenic units : synthesis, properties, applications

    NARCIS (Netherlands)

    Everaars, M.D.

    1997-01-01

    When the structural characteristics of amphiphiles and thermotropic liquid crystals are combined in one molecule i.e. a polar headgroup with apolar tails and mesogenic units, compounds are obtained which can exhibit both thermotropic and lyotropic mesomorphism. This class of compounds is

  19. Versatility of cyclodextrins in self-assembly systems of amphiphiles.

    Science.gov (United States)

    Jiang, Lingxiang; Yan, Yun; Huang, Jianbin

    2011-11-14

    Recently, cyclodextrins (CDs) were found to play important yet complicated (or even apparently opposite sometimes) roles in self-assembly systems of amphiphiles or surfactants. Herein, we try to review and clarify the versatility of CDs in surfactant assembly systems by 1) classifying the roles played by CDs into two groups (modulator and building unit) and four subgroups (destructive and constructive modulators, amphiphilic and unamphiphilic building units), 2) comparing these subgroups, and 3) analyzing mechanisms. As a modulator, although CDs by themselves do not participate into the final surfactant aggregates, they can greatly affect the aggregates in two ways. In most cases CDs will destroy the aggregates by depleting surfactant molecules from the aggregates (destructive), or in certain cases CDs can promote the aggregates to grow by selectively removing the less-aggregatable surfactant molecules from the aggregates (constructive). As an amphiphilic building unit, CDs can be chemically (by chemical bonds) or physically (by host-guest interaction) attached to a hydrophobic moiety, and the resultant compounds act as classic amphiphiles. As an unamphiphilic building unit, CD/surfactant complexes or even CDs on their own can assemble into aggregates in an unconventional, unamphiphilic manner driven by CD-CD H-bonds. Moreover, special emphasis is put on two recently appeared aspects: the constructive modulator and unamphiphilic building unit. Copyright © 2011 Elsevier B.V. All rights reserved.

  20. Effects of perfluorinated amphiphiles on backward swimming in Paramecium caudatum.

    Science.gov (United States)

    Matsubara, Eriko; Harada, Kouji; Inoue, Kayoko; Koizumi, Akio

    2006-01-13

    PFOS and PFOA are ubiquitous contaminants in the environment. We investigated the effects of fluorochemicals on calcium currents in Paramecium caudatum using its behavioral changes. Negatively charged amphiphiles prolonged backward swimming (BWS) of Paramecium. PFOS significantly prolonged BWS, while PFOA was less potent (EC(50): 29.8+/-4.1 and 424.1+/-124.0microM, respectively). The BWS prolongation was blocked by cadmium, indicating that the cellular calcium conductance had been modified. The positively charged amphiphile FOSAPrTMA shortened BWS (EC(50): 19.1+/-17.3). Nonionic amphiphiles did not affect BWS. The longer-chain perfluorinated carboxylates PFNA and PFDA were more potent than PFOA (EC(50): 98.7+/-20.1 and 60.4+/-10.1microM, respectively). However, 1,8-perfluorooctanedioic acid and 1,10-perfluorodecanedioic acid did not prolong BWS. The critical micelle concentration (CMC) and BWS prolongation for negatively charged amphiphiles showed a clear correlation (r(2)=0.8008, pParamecium, while chain length, CMC, and electric charge were major determinants of BWS duration.

  1. Reinforcement of latex rubber by the incorporation of amphiphilic particles

    Science.gov (United States)

    Latex rubbers are fabricated from latex suspensions. During the fabrication process, latex particles are bound together while water is removed from the suspension. This report shows that the mechanical properties of latex rubbers can be improved by incorporating a small amount of amphiphilic submicr...

  2. Self-assembly of fibronectin mimetic peptide-amphiphile nanofibers

    Science.gov (United States)

    Rexeisen, Emilie Lynn

    Many therapeutic strategies incorporate peptides into their designs to mimic the natural protein ligands found in vivo. A few examples are the short peptide sequences RGD and PHSRN that mimic the primary and synergy-binding domains of the extracellular matrix protein, fibronectin, which is recognized by the cell surface receptor, alpha5beta 1 integrin. Even though scaffold modification with biomimetic peptides remains one of the most promising approaches for tissue engineering, the use of these peptides in therapeutic tissue-engineered products and drug delivery systems available on the commercial market is limited because the peptides are not easily able to mimic the natural protein. The design of a peptide that can effectively target the alpha5beta1 integrin would greatly increase biomimetic scaffold therapeutic potential. A novel peptide containing both the RGD primary binding domain and PHSRN synergy-binding domain for fibronectin joined with the appropriate linker should bind alpha 5beta1 integrin more efficiently and lead to greater cell adhesion over RGD alone. Several fibronectin mimetic peptides were designed and coupled to dialkyl hydrocarbon tails to make peptide-amphiphiles. The peptides contained different linkers connecting the two binding domains and different spacers separating the hydrophobic tails from the hydrophilic headgroups. The peptide-amphiphiles were deposited on mica substrates using the Langmuir-Blodgett technique. Langmuir isotherms indicated that the peptide-amphiphiles that contained higher numbers of serine residues formed a more tightly packed monolayer, but the increased number of serines also made transferring the amphiphiles to the mica substrate more difficult. Atomic force microscopy (AFM) images of the bilayers showed that the headgroups might be bent, forming small divots in the surface. These divots may help expose the PHSRN synergy-binding domain. Parallel studies undertaken by fellow group members showed that human

  3. Preparation and Characterization of Amphiphilic Triblock Terpolymer-Based Nanofibers as Antifouling Biomaterials

    KAUST Repository

    Cho, Youngjin

    2012-05-14

    Antifouling surfaces are critical for the good performance of functional materials in various applications including water filtration, medical implants, and biosensors. In this study, we synthesized amphiphilic triblock terpolymers (tri-BCPs, coded as KB) and fabricated amphiphilic nanofibers by electrospinning of solutions prepared by mixing the KB with poly(lactic acid) (PLA) polymer. The resulting fibers with amphiphilic polymer groups exhibited superior antifouling performance to the fibers without such groups. The adsorption of bovine serum albumin (BSA) on the amphiphilic fibers was about 10-fold less than that on the control surfaces from PLA and PET fibers. With the increase of the KB content in the amphiphilic fibers, the resistance to adsorption of BSA was increased. BSA was released more easily from the surface of the amphiphilic fibers than from the surface of hydrophobic PLA or PET fibers. We have also investigated the structural conformation of KB in fibers before and after annealing by contact angle measurements, transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), and coarse-grained molecular dynamics (CGMD) simulation to probe the effect of amphiphilic chain conformation on antifouling. The results reveal that the amphiphilic KB was evenly distributed within as-spun hybrid fibers, while migrated toward the core from the fiber surface during thermal treatment, leading to the reduction in antifouling. This suggests that the antifouling effect of the amphiphilic fibers is greatly influenced by the arrangement of amphiphilic groups in the fibers. © 2012 American Chemical Society.

  4. Development of polycationic amphiphilic cyclodextrin nanoparticles for anticancer drug delivery

    Directory of Open Access Journals (Sweden)

    Gamze Varan

    2017-07-01

    Full Text Available Background: Paclitaxel is a potent anticancer drug that is effective against a wide spectrum of cancers. To overcome its bioavailability problems arising from very poor aqueous solubility and tendency to recrystallize upon dilution, paclitaxel is commercially formulated with co-solvents such as Cremophor EL® that are known to cause serious side effects during chemotherapy. Amphiphilic cyclodextrins are favored oligosaccharides as drug delivery systems for anticancer drugs, having the ability to spontaneously form nanoparticles without surfactant or co-solvents. In the past few years, polycationic, amphiphilic cyclodextrins were introduced as effective agents for gene delivery in the form of nanoplexes. In this study, the potential of polycationic, amphiphilic cyclodextrin nanoparticles were evaluated in comparison to non-ionic amphiphilic cyclodextrins and core–shell type cyclodextrin nanoparticles for paclitaxel delivery to breast tumors. Pre-formulation studies were used as a basis for selecting the suitable organic solvent and surfactant concentration for the novel polycationic cyclodextrin nanoparticles. The nanoparticles were then extensively characterized with particle size distribution, polydispersity index, zeta potential, drug loading capacity, in vitro release profiles and cytotoxicity studies.Results: Paclitaxel-loaded cyclodextrin nanoparticles were obtained in the diameter range of 80−125 nm (depending on the nature of the cyclodextrin derivative where the smallest diameter nanoparticles were obtained with polycationic (PC βCDC6. A strong positive charge also helped to increase the loading capacity of the nanoparticles with paclitaxel up to 60%. Interestingly, cyclodextrin nanoparticles were able to stabilize paclitaxel in aqueous solution for 30 days. All blank cyclodextrin nanoparticles were demonstrated to be non-cytotoxic against L929 mouse fibroblast cell line. In addition, paclitaxel-loaded nanoparticles have a

  5. Ternary rare earth-lanthanide sulfides

    Science.gov (United States)

    Takeshita, Takuo; Gschneidner, Jr., Karl A.; Beaudry, Bernard J.

    1987-01-06

    A new ternary rare earth sulfur compound having the formula: La.sub.3-x M.sub.x S.sub.4 where M is a rare earth element selected from the group europium, samarium and ytterbium and x=0.15 to 0.8. The compound has good high-temperature thermoelectric properties and exhibits long-term structural stability up to 1000.degree. C.

  6. Panchromatic Sequentially Cast Ternary Polymer Solar Cells.

    Science.gov (United States)

    Ghasemi, Masoud; Ye, Long; Zhang, Qianqian; Yan, Liang; Kim, Joo-Hyun; Awartani, Omar; You, Wei; Gadisa, Abay; Ade, Harald

    2017-01-01

    A sequential-casting ternary method is developed to create stratified bulk heterojunction (BHJ) solar cells, in which the two BHJ layers are spin cast sequentially without the need of adopting a middle electrode and orthogonal solvents. This method is found to be particularly useful for polymers that form a mechanically alloyed morphology due to the high degree of miscibility in the blend. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Ternary alloy nanocatalysts for hydrogen evolution reaction

    Indian Academy of Sciences (India)

    Cu–Fe–Ni ternary alloys (size ∼55–80 nm) with varying compositions viz. CuFeNi (A1), CuFe2Ni (A2) and CuFeNi2 (A3) were successfully synthesized using microemulsion. It is to be noted that synthesis of nanocrystallineternary alloys with precise composition is a big challenge which can be overcome by choosing an ...

  8. Equilibrium study for ternary mixtures of biodiesel

    Science.gov (United States)

    Doungsri, S.; Sookkumnerd, T.; Wongkoblap, A.; Nuchitprasittichai, A.

    2017-11-01

    The liquid-liquid equilibrium (LLE) data for the ternary mixtures of methanol + fatty acid methyl ester (FAME) + palm oil and FAME + palm oil + glycerol at various temperatures from 35 to 55°C, the tie lines and binodial curves were also investigated and plotted in the equilibrium curve. The experimental results showed that the binodial curves of methanol + FAME + palm oil depended significantly with temperature while the binodial curves of FAME + palm oil + glycerol illustrated insignificant change with temperatures. The interaction parameters between liquid pair obtained for NRTL (Nonrandom Two-Liquid) and UNIQUAC (Universal Quasi-Chemical Theory) models from the experimental data were also investigated. It was found that the correlated parameters of UNIQUAC model for system of FAME + palm oil + glycerol, denoted as a13 and a31, were 580.42K and -123.69K, respectively, while those for system of methanol + FAME + palm oil, denoted as a42 and a24, were 71.48 K and 965.57K, respectively. The ternary LLE data reported here would be beneficial for engineers and scientists to use for prediction of yield and purity of biodiesel for the production. The UNIQUAC model agreed well with the experimental data of ternary mixtures of biodiesel.

  9. The Ternary Alpha Energy Distribution Revisited

    Science.gov (United States)

    Wagemans, Cyriel; Janssens, Peter; Heyse, Jan; Serot, Olivier; Geltenbort, Peter; Soldner, Torsten

    2004-02-01

    The shape of the energy distribution of the particles emitted in ternary fission has been studied since the discovery of the phenomenon for a large variety of fissioning systems. The general tendency of the observations is that most particles have a Gaussian-shaped energy distribution, except the α-particles, for which mostly an important non-Gaussian tailing on the low-energy side is reported. The origin of this tailing is generally ascribed to the decay of ternary 5He particles in an α-particle and a neutron. Since the experiments reported in the literature are rarely optimised for measuring the low-energy part of the α-spectrum, we realised good experimental conditions for studying the 235U(nth,f) ternary α energy distribution at the High Flux Reactor of the ILL in Grenoble. Thanks to a very intense and clean neutron beam, a small, very thin sample of highly enriched U could be used, with an activity of only 1.6 Bq. So the measurements could be done without absorber in between the sample and the ΔE-E detector. With the resulting low detection limit of 6 MeV, a clearly asymmetric energy distribution was obtained, in agreement with most data in the literature.

  10. More statistics on intermetallic compounds - ternary phases.

    Science.gov (United States)

    Dshemuchadse, Julia; Steurer, Walter

    2015-05-01

    How many different intermetallic compounds are known so far, and in how many different structure types do they crystallize? What are their chemical compositions, the most abundant ones and the rarest ones? These are some of the questions we are trying to find answers for in our statistical analysis of the structures of the 20,829 intermetallic phases included in the database Pearson's Crystal Data, with the goal of gaining insight into some of their ordering principles. In the present paper, we focus on the subset of 13,026 ternary intermetallics, which crystallize in 1391 different structure types; remarkably, 667 of them have just one representative. What makes these 667 structures so unique that they are not adopted by any other of the known intermetallic compounds? Notably, ternary compounds are known in only 5109 of the 85,320 theoretically possible ternary intermetallic systems so far. In order to get an overview of their chemical compositions we use structure maps with Mendeleev numbers as ordering parameters.

  11. Lyotropic liquid crystal engineering-ordered nanostructured small molecule amphiphile self-assembly materials by design.

    Science.gov (United States)

    Fong, Celesta; Le, Tu; Drummond, Calum J

    2012-02-07

    Future nanoscale soft matter design will be guided to a large extent by the teachings of amphiphile (lipid or surfactant) self-assembly. Ordered nanostructured lyotropic liquid crystalline mesophases may form in select mixtures of amphiphile and solvent. To reproducibly engineer the low energy amphiphile self-assembly of materials for the future, we must first learn the design principles. In this critical review we discuss the evolution of these design rules and in particular discuss recent key findings regarding (i) what drives amphiphile self-assembly, (ii) what governs the self-assembly structures that are formed, and (iii) how can amphiphile self-assembly materials be used to enhance product formulations, including drug delivery vehicles, medical imaging contrast agents, and integral membrane protein crystallisation media. We focus upon the generation of 'dilutable' lyotropic liquid crystal phases with two- and three-dimensional geometries from amphiphilic small molecules (225 references). This journal is © The Royal Society of Chemistry 2012

  12. Highly tunable photoluminescent properties of amphiphilic conjugated block copolymers.

    Science.gov (United States)

    Park, Sang-Jae; Kang, Seung-Gu; Fryd, Michael; Saven, Jeffery G; Park, So-Jung

    2010-07-28

    We report a novel class of amphiphilic conjugated block copolymers composed of poly(3-octylthiophene) and poly(ethylene oxide) (POT-b-PEO) that exhibit highly tunable photoluminescence colors spanning from blue to red. POT-b-PEO self-assembles into various well-defined core/shell-type nanostructures as a result of its amphiphilicity. The self-assembly structure can be readily controlled by altering the solvent composition or by other external stimuli. The color change was completely reversible, demonstrating that the strategy can be used to manipulate the light-emission properties of conjugated polymers in a highly controllable manner without having to synthesize entirely new sets of molecules.

  13. Amphiphiles in aqueous solution: well beyond a soap bubble.

    Science.gov (United States)

    Sorrenti, A; Illa, O; Ortuño, R M

    2013-11-07

    Owing to their "dual" affinity, amphiphiles self-assemble in water to form different kinds of nanoscale multimolecular assemblies ranging from simple micelles and vesicles to highly organized fibers, helices and tubes. In this tutorial review the aggregates formed in water by head/tail amphiphiles are revisited and discussed from the point of view of supramolecular chemistry with a focus on their structure and recognition abilities. Their applications in materials chemistry, as soft templates for inorganic nanostructures, as well as in biological and medicinal chemistry are also illustrated. Special attention is paid to highlight intriguing aspects, for example the control of morphology and chirality, their modulation by experimental parameters and chiral symmetry breaking.

  14. "Micro-pottery"--marangoni effect driven assembly of amphiphilic fibers.

    Science.gov (United States)

    Raut, Janhavi S; Bhattad, Pradeep; Kulkarni, Aditi C; Naik, Vijay M

    2005-01-18

    We report spontaneous supra-assembly of fibrous surfactant crystallites at the air-solution interface resulting in spectacular arrays of two-dimensional spiral and three-dimensional "micro-pottery"-like superstructures. Surface pressure differential driven bending of the embryonic fiber nuclei and Marangoni convection driven fiber migration/alignment appear to be the causal factors behind this phenomenon. The assemblies form at specific crystal-growth velocities dictated by the relative time scales for fiber bending/alignment and their rigidification/immobilization as they grow. Although our studies are restricted to a specific class of amphiphiles, namely, alkaline metal salts of linear fatty acids, the phenomenon should be generic to amphiphilic molecules that crystallize into flexible fibers.

  15. Preparation and self-folding of amphiphilic DNA origami.

    Science.gov (United States)

    Zhou, Chao; Wang, Dianming; Dong, Yuanchen; Xin, Ling; Sun, Yawei; Yang, Zhongqiang; Liu, Dongsheng

    2015-03-01

    Amphiphilic DNA origami is prepared by dressing multiple hydrophobic molecules on a rectangular single layer DNA origami, which is then folded or coupled in sandwich-like structures with two outer DNA origami layer and one inner hydrophobic molecules layer. The preference to form different kinds of structures could be tailored by rational design of DNA origami. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. A defect mediated lamellar to isotropic transition of amphiphile bilayers

    OpenAIRE

    Pal, Antara; Pabst, Georg; Raghunathan, V. A.

    2011-01-01

    We report the observation of a novel isotropic phase of amphiphile bilayers in a mixed system consisting of the ionic surfactant, sodium docecylsulphate (SDS), and the organic salt p-toludine hydrochloride (PTHC). This system forms a collapsed lamellar ($L_\\alpha$) phase over a wide range of water content, which transforms into an isotropic phase on heating. This transition is not observed in samples without excess water, where the $L_\\alpha$ phase is stable at higher temperatures. Our observ...

  17. Amphiphilic Phospholipid-Based Riboflavin Derivatives for Tumor Targeting Nanomedicines.

    Science.gov (United States)

    Beztsinna, Nataliia; Tsvetkova, Yoanna; Bartneck, Matthias; Lammers, Twan; Kiessling, Fabian; Bestel, Isabelle

    2016-09-21

    Riboflavin (RF) is an essential vitamin for cellular metabolism. Recent studies have shown that RF is internalized through RF transporters, which are highly overexpressed by prostate and breast cancer cells, as well as by angiogenic endothelium. Here, we present an optimized synthesis protocol for preparing tailor-made amphiphilic phospholipid-based RF derivatives using phosphoramidite chemistry. The prepared RF amphiphile-RfdiC14-can be inserted into liposome formulations for targeted drug delivery. The obtained liposomes had a hydrodynamic size of 115 ± 5 nm with narrow size distribution (PDI 0.06) and a zeta potential of -52 ± 3 mV. In vitro uptake studies showed that RfdiC14-containing liposomes were strongly internalized in HUVEC, PC3, and A431 cells, in a specific and transporter-mediated manner. To assess the RF targeting potential in vivo, an amphiphile containing PEG spacer between RF and a lipid was prepared-DSPE-PEG-RF. The latter was successfully incorporated into long-circulating near-infrared-labeled liposomes (141 ± 1 nm in diameter, PDI 0.07, zeta potential of -33 ± 1 mV). The longitudinal μCT/FMT biodistribution studies in PC3 xenograft bearing mice demonstrated similar pharmacokinetics profile of DSPE-PEG-RF-functionalized liposomes compared to control. The subsequent histological evaluation of resected tumors revealed higher degree of tumor retention as well as colocalization of targeted liposomes with endothelial cells emphasizing the targeting potential of RF amphiphiles and their utility for the lipid-containing drug delivery systems.

  18. Amphiphilic cationic peptides mediate cell adhesion to plastic surfaces.

    Science.gov (United States)

    Rideout, D C; Lambert, M; Kendall, D A; Moe, G R; Osterman, D G; Tao, H P; Weinstein, I B; Kaiser, E T

    1985-09-01

    Four amphiphilic peptides, each with net charges of +2 or more at neutrality and molecular weights under 4 kilodaltons, were found to mediate the adhesion of normal rat kidney fibroblasts to polystyrene surfaces. Two of these peptides, a model for calcitonin (peptide 1, MCT) and melittin (peptide 2, MEL), form amphiphilic alpha-helical structures at aqueous/nonpolar interfaces. The other two, a luteinizing hormone-releasing hormone model (peptide 3, LHM) and a platelet factor model (peptide 4, MPF) form beta-strand structures in amphiphilic environments. Although it contains only 10 residues, LHM mediated adhesion to surfaces coated with solutions containing as little as 10 pmoles/ml of peptide. All four of these peptides were capable of forming monolayers at air-buffer interfaces with collapse pressures greater than 20 dynes/cm. None of these four peptides contains the tetrapeptide sequence Arg-Gly-Asp-Ser, which has been associated with fibronectin-mediated cell adhesion. Ten polypeptides that also lacked the sequence Arg-Gly-Asp-Ser but were nonamphiphilic and/or had net charges less than +2 at neutrality were all incapable of mediating cell adhesion (Pierschbacher and Ruoslahti, 1984). The morphologies of NRK cells spread on polystyrene coated with peptide LHM resemble the morphologies on fibronectin-coated surfaces, whereas cells spread on surfaces coated with MCT or MEL exhibit strikingly different morphologies. The adhesiveness of MCT, MEL, LHM, and MPF implies that many amphiphilic cationic peptides could prove useful as well defined adhesive substrata for cell culture and for studies of the mechanism of cell adhesion.

  19. Recent Advances in the Chemistry of Glycoconjugate Amphiphiles.

    Science.gov (United States)

    Latxague, Laurent; Gaubert, Alexandra; Barthélémy, Philippe

    2018-01-02

    Glyconanoparticles essentially result from the (covalent or noncovalent) association of nanometer-scale objects with carbohydrates. Such glyconanoparticles can take many different forms and this mini review will focus only on soft materials (colloids, liposomes, gels etc.) with a special emphasis on glycolipid-derived nanomaterials and the chemistry involved for their synthesis. Also this contribution presents Low Molecular Weight Gels (LMWGs) stabilized by glycoconjugate amphiphiles. Such soft materials are likely to be of interest for different biomedical applications.

  20. Spinodal phase separation in complex fluids

    Science.gov (United States)

    Schmid, F.; Blossey, R.

    1994-07-01

    We study the early stages of the phase separation of an amphiphilic system into two fluids, one structured and the other not, in the context of a one-component order-parameter model. A generalization of the Langer — Bar-on — Miller approximation permits the calculation of the time evolution of the structure function in the mixture. Near the structured-fluid side of the coexistence, we find that the spinodal is much more clearly observable and is closer to the binodal than on the unstructured side.

  1. Page 1 Structure and superconductivity in ternary systems of ...

    Indian Academy of Sciences (India)

    Structure and superconductivity in ternary systems of compounds 299. Erra B2 structure do not have T. above 1:2 K (Ku and Meisner 1981); (iii) for. Ao.67Pt3B the T. are 1-6, 28 and 56K for A = Ca,Sr and Ba (Shelton 1978) and. (iv) AOs B, A = Th, T = 3 K; A = Y, T = 6K (Ku 1980). 3. Ternary carbides. Of the known ternary ...

  2. Tuning Amphiphilicity of Particles for Controllable Pickering Emulsion

    Science.gov (United States)

    Wang, Zhen; Wang, Yapei

    2016-01-01

    Pickering emulsions with the use of particles as emulsifiers have been extensively used in scientific research and industrial production due to their edge in biocompatibility and stability compared with traditional emulsions. The control over Pickering emulsion stability and type plays a significant role in these applications. Among the present methods to build controllable Pickering emulsions, tuning the amphiphilicity of particles is comparatively effective and has attracted enormous attention. In this review, we highlight some recent advances in tuning the amphiphilicity of particles for controlling the stability and type of Pickering emulsions. The amphiphilicity of three types of particles including rigid particles, soft particles, and Janus particles are tailored by means of different mechanisms and discussed here in detail. The stabilization-destabilization interconversion and phase inversion of Pickering emulsions have been successfully achieved by changing the surface properties of these particles. This article provides a comprehensive review of controllable Pickering emulsions, which is expected to stimulate inspiration for designing and preparing novel Pickering emulsions, and ultimately directing the preparation of functional materials. PMID:28774029

  3. Carbohydrate-based amphiphilic nano delivery systems for cancer therapy.

    Science.gov (United States)

    Liu, Kegang; Jiang, Xiaohua; Hunziker, Patrick

    2016-09-15

    Nanoparticles (NPs) are novel drug delivery systems that have been attracting more and more attention in recent years, and have been used for the treatment of cancer, infection, inflammation and other diseases. Among the numerous classes of materials employed for constructing NPs, organic polymers are outstanding due to the flexibility of design and synthesis and the ease of modification and functionalization. In particular, NP based amphiphilic polymers make a great contribution to the delivery of poorly-water soluble drugs. For example, natural, biocompatible and biodegradable products like polysaccharides are widely used as building blocks for the preparation of such drug delivery vehicles. This review will detail carbohydrate based amphiphilic polymeric systems for cancer therapy. Specifically, it focuses on the nature of the polymer employed for the preparation of targeted nanocarriers, the synthetic methods, as well as strategies for the application and evaluation of biological activity. Applications of the amphiphilic polymer systems include drug delivery, gene delivery, photosensitizer delivery, diagnostic imaging and specific ligand-assisted cellular uptake. As a result, a thorough understanding of the relationship between chemical structure and biological properties facilitate the optimal design and rational clinical application of the resulting carbohydrate based nano delivery systems for cancer therapy.

  4. Amphiphilic dendritic peptides: Synthesis and behavior as an organogelator and liquid crystal.

    Science.gov (United States)

    Gao, Baoxiang; Li, Hongxia; Xia, Defang; Sun, Sufang; Ba, Xinwu

    2011-02-11

    New amphiphilic dendritic peptides on dendritic polyaspartic acid were designed and synthesized. The organogel and liquid crystal properties of these amphiphilic dendritic peptides were fully studied by field-emission SEM, temperature dependent FT-IR, differential scanning calorimetry, polarization optical microscopy and X-ray diffraction experiments. Amphiphilic dendritic peptides G3 show good organogel properties with a minimum gelation concentration as low as 1 wt %. Furthermore, amphiphilic dendritic peptides G3 can form a hexagonal columnar liquid crystal assembly over a wide temperature range.

  5. Amphiphilic dendritic peptides: Synthesis and behavior as an organogelator and liquid crystal

    Directory of Open Access Journals (Sweden)

    Xinwu Ba

    2011-02-01

    Full Text Available New amphiphilic dendritic peptides on dendritic polyaspartic acid were designed and synthesized. The organogel and liquid crystal properties of these amphiphilic dendritic peptides were fully studied by field-emission SEM, temperature dependent FT-IR, differential scanning calorimetry, polarization optical microscopy and X-ray diffraction experiments. Amphiphilic dendritic peptides G3 show good organogel properties with a minimum gelation concentration as low as 1 wt %. Furthermore, amphiphilic dendritic peptides G3 can form a hexagonal columnar liquid crystal assembly over a wide temperature range.

  6. Amphiphiles Self-Assembly: Basic Concepts and Future Perspectives of Supramolecular Approaches

    Directory of Open Access Journals (Sweden)

    Domenico Lombardo

    2015-01-01

    Full Text Available Amphiphiles are synthetic or natural molecules with the ability to self-assemble into a wide variety of structures including micelles, vesicles, nanotubes, nanofibers, and lamellae. Self-assembly processes of amphiphiles have been widely used to mimic biological systems, such as assembly of lipids and proteins, while their integrated actions allow the performance of highly specific cellular functions which has paved a way for bottom-up bionanotechnology. While amphiphiles self-assembly has attracted considerable attention for decades due to their extensive applications in material science, drug and gene delivery, recent developments in nanoscience stimulated the combination of the simple approaches of amphiphile assembly with the advanced concept of supramolecular self-assembly for the development of more complex, hierarchical nanostructures. Introduction of stimulus responsive supramolecular amphiphile assembly-disassembly processes provides particularly novel approaches for impacting bionanotechnology applications. Leading examples of these novel self-assembly processes can be found, in fact, in biosystems where assemblies of different amphiphilic macrocomponents and their integrated actions allow the performance of highly specific biological functions. In this perspective, we summarize in this tutorial review the basic concept and recent research on self-assembly of traditional amphiphilic molecules (such as surfactants, amphiphile-like polymers, or lipids and more recent concepts of supramolecular amphiphiles assembly which have become increasingly important in emerging nanotechnology.

  7. Ultrabright and multicolorful fluorescence of amphiphilic polyethyleneimine polymer dots for efficiently combined imaging and therapy

    National Research Council Canada - National Science Library

    Sun, Yun; Cao, Weipeng; Li, Shengliang; Jin, Shubin; Hu, Kelei; Hu, Liming; Huang, Yuanyu; Gao, Xueyun; Wu, Yan; Liang, Xing-Jie

    2013-01-01

    .... The weak fluorescent polyethyleneimine (PEI) has been conjugated with hydrophobic polylactide as the amphiphilic PEI for construction of nanoparticles which showed bright and multicolor fluorescence...

  8. Ternary q-Virasoro-Witt Hom-Nambu-Lie algebras

    Energy Technology Data Exchange (ETDEWEB)

    Ammar, F [Faculte des Sciences, Universite de Sfax, BP 1171, 3000 Sfax (Tunisia); Makhlouf, A [Laboratoire de Mathematiques, Informatique et Applications, Universite de Haute Alsace, 4, rue des Freres Lumiere F-68093 Mulhouse (France); Silvestrov, S, E-mail: Faouzi.Ammar@rnn.fss.t, E-mail: Abdenacer.Makhlouf@uha.f, E-mail: sergei.silvestrov@math.lth.s [Centre for Mathematical Sciences, Lund University, Box 118, SE-221 00 Lund (Sweden)

    2010-07-02

    In this paper we construct ternary q-Virasoro-Witt algebras which q-deform the ternary Virasoro-Witt algebras constructed by Curtright, Fairlie and Zachos using su(1, 1) enveloping algebra techniques. The ternary Virasoro-Witt algebras constructed by Curtright, Fairlie and Zachos depend on a parameter and are not Nambu-Lie algebras for all but finitely many values of this parameter. For the parameter values for which the ternary Virasoro-Witt algebras are Nambu-Lie, the corresponding ternary q-Virasoro-Witt algebras constructed in this paper are also Hom-Nambu-Lie because they are obtained from the ternary Nambu-Lie algebras using the composition method. For other parameter values this composition method does not yield a Hom-Nambu-Lie algebra structure for q-Virasoro-Witt algebras. We show however, using a different construction, that the ternary Virasoro-Witt algebras of Curtright, Fairlie and Zachos, as well as the general ternary q-Virasoro-Witt algebras we construct, carry a structure of the ternary Hom-Nambu-Lie algebra for all values of the involved parameters.

  9. Dehydration-induced redistribution of amphiphilic molecules between cytoplasm and lipids is associated with desiccation tolerance in seeds

    NARCIS (Netherlands)

    Buitink, J.; Leprince, O.; Hoekstra, F.A.

    2000-01-01

    This study establishes a relationship between desiccation tolerance and the transfer of amphiphilic molecules from the cytoplasm into lipids during drying, using electron paramagnetic resonance spectroscopy of amphiphilic spin probes introduced into imbibed radicles of pea (Pisum sativum) and

  10. Neutron Damage and MAX Phase Ternary Compounds

    Energy Technology Data Exchange (ETDEWEB)

    Barsoum, Michael [Drexel Univ., Philadelphia, PA (United States); Hoffman, Elizabeth [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Sindelar, Robert [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Garcua-Duaz, Brenda [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Kohse, Gordon [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2014-06-17

    The Demands of Gen IV nuclear power plants for long service life under neutron radiation at high temperature are severe. Advanced materials that would withstand high temperatures (up to 1000+ C) to high doses in a neutron field would be ideal for reactor internal structures and would add to the long service life and reliability of the reactors. The objective of this work is to investigate the response of a new class of machinable, conductive, layered, ternary transition metal carbides and nitrides - the so-called MAX phases - to low and moderate neutron dose levels.

  11. Balanced ternary addition using a gated silicon nanowire

    NARCIS (Netherlands)

    Mol, J.A.; Van der Heijden, J.; Verduijn, J.; Klein, M.; Remacle, F.; Rogge, S.

    2011-01-01

    Ternary logic has the lowest cost of complexity, here, we demonstrate a CMOS hardware implementation of a ternary adder using a silicon metal-on-insulator single electron transistor. Gate dependent rectifying behavior of a single electron transistor (SET) results in a robust three-valued output as a

  12. Density-Driven segregation in Binary and Ternary Granular Systems

    NARCIS (Netherlands)

    Windows-Yule, Kit; Parker, David

    2015-01-01

    We present a first experimental study of density-induced segregation within a three-dimensional, vibrofluidised, ternary granular system. Using Positron Emission Particle Tracking (PEPT), we study the steady-state particle distributions achieved by binary and ternary granular beds under a variety of

  13. A high-speed interconnect network using ternary logic

    DEFF Research Database (Denmark)

    Madsen, Jens Kargaard; Long, S. I.

    1995-01-01

    This paper describes the design and implementation of a high-speed interconnect network (ICN) for a multiprocessor system using ternary logic. By using ternary logic and a fast point-to-point communication technique called STARI (Self-Timed At Receiver's Input), the communication between...

  14. Densities and Excess Molar Volume for the Ternary Systems (1 ...

    African Journals Online (AJOL)

    methylimidazolium methyl sulphate ([BMIM]+[MeSO4]-) were determined. The ternary systems studied were ([BMIM]+[MeSO4]-+ nitromethane + methanol or ethanol or 1-propanol) at the temperatures (303.15 and 313.15) K. The ternary excess molar ...

  15. Single polymer-based ternary electronic memory material and device.

    Science.gov (United States)

    Liu, Shu-Juan; Wang, Peng; Zhao, Qiang; Yang, Hui-Ying; Wong, Jenlt; Sun, Hui-Bin; Dong, Xiao-Chen; Lin, Wen-Peng; Huang, Wei

    2012-06-05

    A ternary polymer memory device based on a single polymer with on-chain Ir(III) complexes is fabricated by combining multiple memory mechanisms into one system. Excellent ternary memory performances-low reading, writing, and erasing voltages and good stability for all three states-are achieved. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Formation of ternary Mg–Cu–Dy bulk metallic glasses

    Indian Academy of Sciences (India)

    Administrator

    Abstract. The glass-forming ability (GFA) of ternary Mg–Cu–Dy alloys was systematically investigated by using differential scanning calorimetry (DSC) and X-ray diffractometry (XRD) techniques. The results showed that a series of ternary Mg–Cu–Dy bulk metallic glasses (BGMs) with a diameter of 4–8 mm were suc-.

  17. Linker-determined drug release mechanism of free camptothecin from self-assembling drug amphiphiles.

    Science.gov (United States)

    Cheetham, Andrew G; Ou, Yu-Chuan; Zhang, Pengcheng; Cui, Honggang

    2014-06-07

    We report here that the release mechanism of free camptothecin from self-assembling drug amphiphiles can be regulated by use of different linker groups. Our results highlight the significance of the linker group of drug amphiphiles on the drug release efficiency and their consequent in vitro efficacy.

  18. Exploring single chain amphiphile self-assembly and their possible roles in light transduction

    DEFF Research Database (Denmark)

    Monnard, Pierre-Alain

    2011-01-01

    source studied to date can supply one single type of amphiphile at concentrations conducive to self-assembly. Mixtures of single-chain amphiphiles were therefore proposed to better model primitive membranes and potentially enhance their structural integrity1-3. Recently, we have established that complex...

  19. Synthesis of a new generation of amphiphiles with multi-cryptand ...

    Indian Academy of Sciences (India)

    A laterally non-symmetric aza cryptand has been derivatized with two hydrophobic chains to afford amphiphiles with one cryptand headgroup and two hydrophobic tails. Three such units readily attach to 1,3,5-benzenetricarbonyl trichloride, to form a new generation of amphiphilic molecules with three cryptand headgroups ...

  20. Self-assembly of peptide-amphiphile nanofibers under physiological conditions

    Science.gov (United States)

    Stupp, Samuel I [Chicago, IL; Hartgerink, Jeffrey D [Pearland, TX; Beniash, Elia [Auburndale, MA

    2011-11-22

    The present invention provides a method of promoting neuron growth and development by contacting cells with a peptide amphiphile molecule in an aqueous solution in the presence of a metal ion. According to the method, the peptide amphiphile forms a cylindrical micellar nanofiber composed of beta-sheets, which promote neuron growth and development.

  1. Composition and method for self-assembly and mineralization of peptide amphiphiles

    Science.gov (United States)

    Stupp, Samuel I [Chicago, IL; Beniash, Elia [Newton, MA; Hartgerink, Jeffrey D [Houston, TX

    2009-06-30

    The present invention is directed to a composition useful for making homogeneously mineralized self assembled peptide-amphiphile nanofibers and nanofiber gels. The composition is generally a solution comprised of a positively or negatively charged peptide-amphiphile and a like signed ion from the mineral. Mixing this solution with a second solution containing a dissolved counter-ion of the mineral and/or a second oppositely charged peptide amphiphile, results in the rapid self assembly of the peptide-amphiphiles into a nanofiber gel and templated mineralization of the ions. Templated mineralization of the initially dissolved mineral cations and anions in the mixture occurs with preferential orientation of the mineral crystals along the fiber surfaces within the nanofiber gel. One advantage of the present invention is that it results in homogenous growth of the mineral throughout the nanofiber gel. Another advantage of the present invention is that the nanofiber gel formation and mineralization reactions occur in a single mixing step and under substantially neutral or physiological pH conditions. These homogeneous nanostructured composite materials are useful for medical applications especially the regeneration of damaged bone in mammals. This invention is directed to the synthesis of peptide-amphiphiles with more than one amphiphilic moment and to supramolecular compositions comprised of such multi-dimensional peptide-amphiphiles. Supramolecular compositions can be formed by self assembly of multi-dimensional peptide-amphiphiles by mixing them with a solution comprising a monovalent cation.

  2. Composition and method for self-assembly and mineralization of peptide-amphiphiles

    Science.gov (United States)

    Stupp, Samuel I [Chicago, IL; Beniash, Elia [Newton, MA; Hartgerink, Jeffrey D [Pearland, TX

    2012-02-28

    The present invention is directed to a composition useful for making homogeneously mineralized self assembled peptide-amphiphile nanofibers and nanofiber gels. The composition is generally a solution comprised of a positively or negatively charged peptide-amphiphile and a like signed ion from the mineral. Mixing this solution with a second solution containing a dissolved counter-ion of the mineral and/or a second oppositely charged peptide amphiphile, results in the rapid self assembly of the peptide-amphiphiles into a nanofiber gel and templated mineralization of the ions. Templated mineralization of the initially dissolved mineral cations and anions in the mixture occurs with preferential orientation of the mineral crystals along the fiber surfaces within the nanofiber gel. One advantage of the present invention is that it results in homogenous growth of the mineral throughout the nanofiber gel. Another advantage of the present invention is that the nanofiber gel formation and mineralization reactions occur in a single mixing step and under substantially neutral or physiological pH conditions. These homogeneous nanostructured composite materials are useful for medical applications especially the regeneration of damaged bone in mammals. This invention is directed to the synthesis of peptide-amphiphiles with more than one amphiphilic moment and to supramolecular compositions comprised of such multi-dimensional peptide-amphiphiles. Supramolecular compositions can be formed by self assembly of multi-dimensional peptide-amphiphiles by mixing them with a solution comprising a monovalent cation.

  3. The bending rigidity of an amphiphilic bilayer from equilibrium and nonequilibrium molecular dynamics

    NARCIS (Netherlands)

    den Otter, Wouter K.; Briels, Willem J.

    2003-01-01

    Helfrich's theory predicts that the bending free energy of a tensionless amphiphilic bilayer is proportional to the square of the Fourier coefficients of the undulation modes. Equilibrium molecular dynamics simulations with coarse-grained amphiphiles confirm the correctness of this prediction for

  4. Polycation-Based Ternary Gene Delivery System.

    Science.gov (United States)

    Liu, Shuai; Guo, Tianying

    2015-01-01

    Recent progress in gene therapy has opened the door for various human diseases. The greatest challenge that gene vectors still face is the ability to sufficiently deliver nucleic acid into target cells. To overcome various barriers, plenty of researches have been undertaken utilizing diverse strategies, among which a wide variety of polycation/pDNA vectors have been developed and explored frequently. For enhanced transfection efficiency, polycations are constantly utilized with covalent modifications, which however lead to reduced positive charge density and changed properties of polycation/pDNA complexes. Accordingly, non-covalent or ternary strategy is proposed. The cationic properties of polycations can be retained and the transfection efficiency can be enhanced by introducing additional polymers with functional groups via non-covalent assembly. This review will discuss the construction and advantages of ternary complexes gene delivery system, including low toxicity and enhanced gene expression both in vitro and in vivo. Recent progress and expectations with promising results that may have some reference for clinical application are also discussed.

  5. Plasmonic spectral tunability of conductive ternary nitrides

    Energy Technology Data Exchange (ETDEWEB)

    Kassavetis, S.; Patsalas, P., E-mail: ppats@physics.auth.gr [Department of Physics, Aristotle University of Thessaloniki, GR-54124 Thessaloniki (Greece); Bellas, D. V.; Lidorikis, E. [Department of Materials Science and Engineering, University of Ioannina, GR-45110 Ioannina (Greece); Abadias, G. [Institut Pprime, Département Physique et Mécanique des Matériaux, Université de Poitiers-CNRS-ENSMA, 86962 Chasseneuil-Futuroscope (France)

    2016-06-27

    Conductive binary transition metal nitrides, such as TiN and ZrN, have emerged as a category of promising alternative plasmonic materials. In this work, we show that ternary transition metal nitrides such as Ti{sub x}Ta{sub 1−x}N, Ti{sub x}Zr{sub 1−x}N, Ti{sub x}Al{sub 1−x}N, and Zr{sub x}Ta{sub 1−x}N share the important plasmonic features with their binary counterparts, while having the additional asset of the exceptional spectral tunability in the entire visible (400–700 nm) and UVA (315–400 nm) spectral ranges depending on their net valence electrons. In particular, we demonstrate that such ternary nitrides can exhibit maximum field enhancement factors comparable with gold in the aforementioned broadband range. We also critically evaluate the structural features that affect the quality factor of the plasmon resonance and we provide rules of thumb for the selection and growth of materials for nitride plasmonics.

  6. Irregular Homogeneity Domains in Ternary Intermetallic Systems

    Directory of Open Access Journals (Sweden)

    Jean-Marc Joubert

    2015-12-01

    Full Text Available Ternary intermetallic A–B–C systems sometimes have unexpected behaviors. The present paper examines situations in which there is a tendency to simultaneously form the compounds ABx, ACx and BCx with the same crystal structure. This causes irregular shapes of the phase homogeneity domains and, from a structural point of view, a complete reversal of site occupancies for the B atom when crossing the homogeneity domain. This work reviews previous studies done in the systems Fe–Nb–Zr, Hf–Mo–Re, Hf–Re–W, Mo–Re–Zr, Re–W–Zr, Cr–Mn–Si, Cr–Mo–Re, and Mo–Ni–Re, and involving the topologically close-packed Laves, χ and σ phases. These systems have been studied using ternary isothermal section determination, DFT calculations, site occupancy measurement using joint X-ray, and neutron diffraction Rietveld refinement. Conclusions are drawn concerning this phenomenon. The paper also reports new experimental or calculated data on Co–Cr–Re and Fe–Nb–Zr systems.

  7. Interaction of amphiphiles with integral membrane proteins. II. A simple, minimal model for the nonspecific interaction of amphiphiles with the anion exchanger of the erythrocyte membrane.

    Science.gov (United States)

    Gruber, H J

    1988-10-20

    In a previous paper we have reported on the structural perturbation of the erythrocyte membrane anion exchanger by a regular series of model amphiphiles, as shown by differential scanning calorimetry (Gruber, H.J. and Low, P.S., Biochim. Biophys. Acta, preceding article). Now the data are interpreted by a model in which the effects of amphiphile structure upon buffer-membrane partitioning are well separated from the dependence of the intrinsic potencies of membrane-bound amphiphiles upon amphiphile structure. The buffer-membrane partitioning situation was demonstrated to regularly change between extremes within a series of homologous amphiphiles, i.e. from a negligible to a predominant fraction of total amphiphile in the sample residing in the membrane. Based upon this demonstration a large number of reports on the chain length dependence of apparent potency could be reinterpreted in terms of chain length profiles of intrinsic potency, allowing for a comparison of the responses of various membrane proteins to homologous series of amphiphiles. The response patterns for chain length variation could be divided into three distinct classes: the intrinsic potency (i) can be independent of chain length over a very wide range of length, (ii) it can be rather independent up to a critical length where a sudden cut-off in potency occurs, or (iii) it can drop monotonically over a wide range of chain length. The intrinsic potency values of saturated fatty acids in destabilizing the anion exchanger were interpreted by very simple assumptions: only direct interactions between amphiphiles and target proteins and a simple amphiphile partition equilibrium between a pool of equivalent low affinity sites on the protein and the bulk lipid matrix. The observed monotonic decay of the intrinsic potency of saturated fatty acids with increasing chain length from C8 to C20 was translated into a constant increment of free energy by which each additional CH2 favors the transfer away from sites

  8. Vesicles from Amphiphilic Dumbbells and Janus Dendrimers: Bioinspired Self-Assembled Structures for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Soraya Taabache

    2017-07-01

    Full Text Available The current review focuses on vesicles obtained from the self-assembly of two types of dendritic macromolecules, namely amphiphilic Janus dendrimers (forming dendrimersomes and amphiphilic dumbbells. In the first part, we will present some synthetic strategies and the various building blocks that can be used to obtain dendritic-based macromolecules, thereby showing their structural versatility. We put our focus on amphiphilic Janus dendrimers and amphiphilic dumbbells that form vesicles in water but we also encompass vesicles formed thereof in organic solvents. The second part of this review deals with the production methods of these vesicles at the nanoscale but also at the microscale. Furthermore, the influence of various parameters (intrinsic to the amphiphilic JD and extrinsic—from the environment on the type of vesicle formed will be discussed. In the third part, we will review the numerous biomedical applications of these vesicles of nano- or micron-size.

  9. Loading of Vesicles into Soft Amphiphilic Nanotubes using Osmosis.

    Science.gov (United States)

    Erne, Petra M; van Bezouwen, Laura S; Štacko, Peter; van Dijken, Derk Jan; Chen, Jiawen; Stuart, Marc C A; Boekema, Egbert J; Feringa, Ben L

    2015-12-07

    The facile assembly of higher-order nanoarchitectures from simple building blocks is demonstrated by the loading of vesicles into soft amphiphilic nanotubes using osmosis. The nanotubes are constructed from rigid interdigitated bilayers which are capped with vesicles comprising phospholipid-based flexible bilayers. When a hyperosmotic gradient is applied to these vesicle-capped nanotubes, the closed system loses water and the more flexible vesicle bilayer is pulled inwards. This leads to inclusion of vesicles inside the nanotubes without affecting the tube structure, showing controlled reorganization of the self-assembled multicomponent system upon a simple osmotic stimulus. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Self-assembly of active amphiphilic Janus particles

    Science.gov (United States)

    Mallory, S. A.; Alarcon, F.; Cacciuto, A.; Valeriani, C.

    2017-12-01

    In this article, we study the phenomenology of a two dimensional dilute suspension of active amphiphilic Janus particles. We analyze how the morphology of the aggregates emerging from their self-assembly depends on the strength and the direction of the active forces. We systematically explore and contrast the phenomenologies resulting from particles with a range of attractive patch coverages. Finally, we illustrate how the geometry of the colloids and the directionality of their interactions can be used to control the physical properties of the assembled active aggregates and suggest possible strategies to exploit self-propulsion as a tunable driving force for self-assembly.

  11. Thermodynamic stability and structural properties of cluster crystals formed by amphiphilic dendrimers

    Science.gov (United States)

    Lenz, Dominic A.; Mladek, Bianca M.; Likos, Christos N.; Blaak, Ronald

    2016-05-01

    We pursue the goal of finding real-world examples of macromolecular aggregates that form cluster crystals, which have been predicted on the basis of coarse-grained, ultrasoft pair potentials belonging to a particular mathematical class [B. M. Mladek et al., Phys. Rev. Lett. 46, 045701 (2006)]. For this purpose, we examine in detail the phase behavior and structural properties of model amphiphilic dendrimers of the second generation by means of monomer-resolved computer simulations. On augmenting the density of these systems, a fluid comprised of clusters that contain several overlapping and penetrating macromolecules is spontaneously formed. Upon further compression of the system, a transition to multi-occupancy crystals takes place, the thermodynamic stability of which is demonstrated by means of free-energy calculations, and where the FCC is preferred over the BCC-phase. Contrary to predictions for coarse-grained theoretical models in which the particles interact exclusively by effective pair potentials, the internal degrees of freedom of these molecules cause the lattice constant to be density-dependent. Furthermore, the mechanical stability of monodisperse BCC and FCC cluster crystals is restricted to a bounded region in the plane of cluster occupation number versus density. The structural properties of the dendrimers in the dense crystals, including their overall sizes and the distribution of monomers are also thoroughly analyzed.

  12. Amphiphilic photosensitive dextran-g-poly(o-nitrobenzyl acrylate) glycopolymers.

    Science.gov (United States)

    Soliman, Soliman Mehawed Abdellatif; Colombeau, Ludovic; Nouvel, Cécile; Babin, Jérôme; Six, Jean-Luc

    2016-01-20

    Among all photosensitive monomers reported in the literature, o-nitrobenzyl acrylate (NBA) was selected in this present study. Two strategies were compared to produce azido-terminated poly(o-nitrobenzyl acrylate) (PNBA) using controlled Single Electron Transfer-Living Radical Polymerization (SET-LRP). In a parallel way, dextran (Dex) was modified by the introduction of several alkynyl-terminated hydrophobic chains. Finally, an Huisgen-type Copper (I)-catalyzed Azide-Alkyne Cycloaddition (CuAAC) click-chemistry was carried out to produce amphiphilic Dex-g-PNBA glycopolymers with different number and length of PNBA grafts. 2D DOSY (1)H NMR was used to prove the formation of such glycopolymers. Preliminary study on Dex-g-PNBA self-assembly was done by measuring the critical water content (CWC) above which Dex-g-PNBA started to auto-organize themselves to produce nano-objects. Finally, under UV irradiation, PNBA grafts turn into poly(acrylic acid) ones giving light-sensitive properties to such amphiphilic Dex-g-PNBA. Such properties were evaluated and compared with those of PNBA. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Perfluorocyclobutyl Aryl Ether-Based ABC Amphiphilic Triblock Copolymer

    Science.gov (United States)

    Xu, Binbin; Yao, Wenqiang; Li, Yongjun; Zhang, Sen; Huang, Xiaoyu

    2016-12-01

    A series of fluorine-containing amphiphilic ABC triblock copolymers comprising hydrophilic poly(ethylene glycol) (PEG) and poly(methacrylic acid) (PMAA), and hydrophobic poly(p-(2-(4-biphenyl)perfluorocyclobutoxy)phenyl methacrylate) (PBPFCBPMA) segments were synthesized by successive atom transfer radical polymerization (ATRP). First, PEG-Br macroinitiators bearing one terminal ATRP initiating group were prepared by chain-end modification of monohydroxy-terminated PEG via esterification reaction. PEG-b-PBPFCBPMA-Br diblock copolymers were then synthesized via ATRP of BPFCBPMA monomer initiated by PEG-Br macroinitiator. ATRP polymerization of tert-butyl methacrylate (tBMA) was directly initiated by PEG-b-PBPFCBPMA-Br to provide PEG-b-PBPFCBPMA-b-PtBMA triblock copolymers with relatively narrow molecular weight distributions (Mw/Mn ≤ 1.43). The pendant tert-butyoxycarbonyls were hydrolyzed to carboxyls in acidic environment without affecting other functional groups for affording PEG-b-PBPFCBPMA-b-PMAA amphiphilic triblock copolymers. The critical micelle concentrations (cmc) were determined by fluorescence spectroscopy using N-phenyl-1-naphthylamine as probe and the self-assembly behavior in aqueous media were investigated by transmission electron microscopy. Large compound micelles and bowl-shaped micelles were formed in neutral aqueous solution. Interestingly, large compound micelles formed by triblock copolymers can separately or simultaneously encapsulate hydrophilic Rhodamine 6G and hydrophobic pyrene agents.

  14. Biodegradable theranostic plasmonic vesicles of amphiphilic gold nanorods.

    Science.gov (United States)

    Song, Jibin; Pu, Lu; Zhou, Jiajing; Duan, Bo; Duan, Hongwei

    2013-11-26

    We have developed surface-initiated organocatalytic ring-opening polymerization on functional nanocrystals and synthesized amphiphilic gold nanorods carrying well-defined mixed polymer brushes of poly(ethylene glycol) and polylactide. Self-assembly of the amphiphilic gold nanorods affords biodegradable plasmonic vesicles that can be destructed by both enzymatic degradation and near-infrared photothermal heating. When tagged with Raman probes, strongly coupled gold nanorods in the self-assembled vesicles give rise to highly active SERS signals. The biodegradable plasmonic vesicles exhibit a unique combination of optical and structural properties that are of particular interest for theranostic applications. We have demonstrated that bioconjugated SERS-active plasmonic vesicles can specifically target EpCAM-positive cancer cells, leading to ultrasensitive spectroscopic detection of cancer cells. Furthermore, integration of photothermal effect of gold nanorods and large loading capacity of the vesicles provides opportunities for localized synergistic photothermal ablation and photoactivated chemotherapy, which have shown higher efficiency in killing targeted cancer cells than either single therapeutic modality. The versatile chemistry of organocatalytic ring-opening polymerization, in conjugation with recent development in synthesizing functional nanocrystals with tailored optical, electronic, and magnetic properties opens the possibilities for constructing multifunctional biodegradable platforms for clinical translation.

  15. Amphiphilic biopolymers (amphibiopols) as new surfactants for membrane protein solubilization

    Science.gov (United States)

    Duval-Terrié, Caroline; Cosette, Pascal; Molle, Gérard; Muller, Guy; Dé, Emmanuelle

    2003-01-01

    The aim of this study was to develop new surfactants for membrane protein solubilization, from a natural, biodegradable polymer: the polysaccharide pullulan. A set of amphiphilic pullulans (HMCMPs), differing in hydrophobic modification ratio, charge ratio, and the nature of the hydrophobic chains introduced, were synthesized and tested in solubilization experiments with outer membranes of Pseudomonas fluorescens. The membrane proteins were precipitated, and then resolubilized with various HMCMPs. The decyl alkyl chain (C10) was the hydrophobic graft that gave the highest level of solubilization. Decyl alkyl chain-bearing HMCMPs were also able to extract integral membrane proteins from their lipid environment. The best results were obtained with an amphiphilic pullulan bearing 18% decyl groups (18C10). Circular dichroism spectroscopy and membrane reconstitution experiments were used to test the structural and functional integrity of 18C10-solubilized proteins (OmpF from Escherichia coli and bacteriorhodopsin from Halobacterium halobium). Whatever their structure type (α or β), 18C10 did not alter either the structure or the function of the proteins analyzed. Thus, HMCMPs appear to constitute a promising new class of polymeric surfactants for membrane protein studies. PMID:12649425

  16. Facile Synthesis of Ternary Boron Carbonitride Nanotubes

    Directory of Open Access Journals (Sweden)

    Luo Lijie

    2009-01-01

    Full Text Available Abstract In this study, a novel and facile approach for the synthesis of ternary boron carbonitride (B–C–N nanotubes was reported. Growth occurred by heating simple starting materials of boron powder, zinc oxide powder, and ethanol absolute at 1150 °C under a mixture gas flow of nitrogen and hydrogen. As substrate, commercial stainless steel foil with a typical thickness of 0.05 mm played an additional role of catalyst during the growth of nanotubes. The nanotubes were characterized by SEM, TEM, EDX, and EELS. The results indicate that the synthesized B–C–N nanotubes exhibit a bamboo-like morphology and B, C, and N elements are homogeneously distributed in the nanotubes. A catalyzed vapor–liquid–solid (VLS mechanism was proposed for the growth of the nanotubes.

  17. The ternary system: Silicon-tantalum-uranium

    Energy Technology Data Exchange (ETDEWEB)

    Rogl, Peter, E-mail: peter.franz.rogl@univie.ac.a [Institute of Physical Chemistry, University of Vienna, A-1090 Wien, Waehringerstrasse 42 (Austria); Noel, Henri [Laboratoire de Chimie du Solide et Materiaux, UMR-CNRS 6226, Universite de Rennes I, Avenue du General Leclerc, F-35042 Rennes, Cedex (France)

    2010-09-01

    Phase equilibria in the ternary system Si-Ta-U have been established in an isothermal section at 1000 {sup o}C by optical microscopy, electron probe microanalysis and X-ray diffraction. Two novel ternary compounds were observed and were characterised by X-ray powder Rietveld refinement: stoichiometric {tau}{sub 1}-U{sub 2}Ta{sub 3}Si{sub 4} (U{sub 2}Mo{sub 3}Si{sub 4}-type, P2{sub 1}/c; a = 0.70011(1), b = 0.70046(1), c = 0.68584(1) nm, ss = 109.38(1); R{sub F} = 0.073, X-ray powder Rietveld refinement) and {tau}{sub 2}-U{sub 2-x}Ta{sub 3+x}Si{sub 4} at x {approx} 0.30 (Sc{sub 2}Re{sub 3}Si{sub 4}-type = partially ordered Zr{sub 5}Si{sub 4}-type, P4{sub 1}2{sub 1}2; a = b = 0.69717(3)(1), c = 1.28709(4) nm; R{sub F} = 0.056; X-ray single crystal data). Mutual solubility of U-silicides and Ta-silicides are found to be very small i.e. below about 1 at.%. Due to the equilibrium tie-line Ta{sub 2}Si-U(Ta), no compatibility exists between the U-rich silicides U{sub 3}Si or U{sub 3}Si{sub 2} and tantalum metal. Single crystals obtained from alloys slowly cooled from liquid (2000 {sup o}C), yielded a fully ordered compound U{sub 2}Ta{sub 2}Si{sub 3}C (unique structure type; Pmna, a = 0.68860(1); b = 2.17837(4); c = 0.69707(1) nm; R{sub F2} = 0.048).

  18. The Landau-Placzek ratio for multicomponent fluids

    NARCIS (Netherlands)

    Lekkerkerker, H.N.W.; Laidlaw, W.G.

    1972-01-01

    Under the assumption that the coupling between the sound modes and modes associated with heat and mass diffusion can be neglected, an expression for the Landau-Placzek ratio for multicomponent fluids is derived using thermodynamic fluctuation theory. Applications of the general formula to ternary

  19. Perfluorinated alcohols and acids induce coacervation in aqueous solutions of amphiphiles.

    Science.gov (United States)

    Khaledi, Morteza G; Jenkins, Samuel I; Liang, Shuang

    2013-02-26

    We have discovered that water-miscible perfluorinated alcohols and acids (FA) can induce simple and complex coacervation in aqueous solutions of a wide range of amphiphilic molecules such as synthetic surfactants, phospholipids, and bile salts as well as polyelectrolytes. This unique phenomenon seems to be nearly ubiquitous, especially for complex coacervate systems composed of mixed catanionic amphiphiles. In addition, coacervation and aqueous phase separation were observed over a wide range of surfactants concentrations and for different mole fractions of the oppositely charged amphiphile.

  20. (CryoTransmission Electron Microscopy of Phospholipid Model Membranes Interacting with Amphiphilic and Polyphilic Molecules

    Directory of Open Access Journals (Sweden)

    Annette Meister

    2017-10-01

    Full Text Available Lipid membranes can incorporate amphiphilic or polyphilic molecules leading to specific functionalities and to adaptable properties of the lipid bilayer host. The insertion of guest molecules into membranes frequently induces changes in the shape of the lipid matrix that can be visualized by transmission electron microscopy (TEM techniques. Here, we review the use of stained and vitrified specimens in (cryoTEM to characterize the morphology of amphiphilic and polyphilic molecules upon insertion into phospholipid model membranes. Special emphasis is placed on the impact of novel synthetic amphiphilic and polyphilic bolalipids and polymers on membrane integrity and shape stability.

  1. Positron annihilation lifetime study of interfaces in ternary polymer blends

    Science.gov (United States)

    Meghala, D.; Ramya, P.; Pasang, T.; Raj, J. M.; Ranganathaiah, C.; Williams, J. F.

    2013-06-01

    A new method based on positron lifetime spectroscopy is developed to characterize individual interfaces in ternary polymer blends and hence determine the composition dependent miscibility level. The method owes its origin to the Kirkwood-Risemann-Zimm (KRZ) model for the evaluation of the hydrodynamic interaction parameters (αij) which was used successfully for a binary blend with a single interface. The model was revised for the present work for ternary polymer blends to account for three interfaces. The efficacy of this method is shown for two ternary blends namely poly(styrene-co-acrylonitrile)/poly (ethylene-co-vinylacetate)/poly(vinyl chloride) (SAN/EVA/PVC) and polycaprolactone /poly(styrene-co-acrylonitrile)/poly(vinyl chloride) (PCL/SAN/PVC) at different compositions. An effective hydrodynamic interaction parameter, αeff, was introduced to predict the overall miscibility of ternary blends.

  2. RGD based peptide amphiphiles as drug carriers for cancer targeting

    Science.gov (United States)

    Saraf, Poonam S.

    Specific interactions of ligands with receptors is one of the approaches for active targeting of anticancer drugs to cancer cells. Over expression of integrin receptors is a physiological manifestation in several cancers and is associated with cancer progression and metastasis, which makes it an attractive target for cancer chemotherapy. The peptide sequence for this integrin recognition is the Arg-Gly-Asp (RGD). Self-assembly offers a unique way of presenting ligands to target receptors for recognition and binding. This study focuses on development of integrin specific peptide amphiphile self-assemblies as carriers for targeted delivery of paclitaxel to αvbeta 3 integrin overexpressing cancers. Amphiphiles composed of conjugates of different analogs of RGD (linear, cyclic or glycosylated) and aliphatic fatty acid with or without 8-amino-3,6-dioxaoctanoic acid (ADA) as linker were synthesized and characterized. The amphiphiles exhibited Critical Micellar Concentration in the range of 7-30 μM. Transmission electron microscopy images revealed the formation of spherical micelles in the size range of 10-40 nm. Forster Resonance Energy Transfer studies revealed entrapment of hydrophobic dyes within a tight micellar core and provided information regarding the cargo exchange within micelles. The RGD micelles exhibited competitive binding with 55% displacement of a bound fluorescent probe by the cyclic RGD micelles. The internalization of fluorescein isothiocynate (FITC) loaded RGD micelles was significantly higher in A2058 melanoma cells compared to free FITC within 20 minutes of incubation at 37°C. The same micelles showed significantly lower internalization at 4°C and on pretreatment with 0.45M sucrose confirming endocytotic uptake of the RGD micellar carriers. The IC50 of paclitaxel in A2058 melanoma cells was lower when treated within RGD micelles as compared to treatment of free drug. On the other hand, IC50 values increased by 2 to 9 fold for micellar treatment

  3. Enthalpy and phase behavior of coal derived liquid mixtures: Technical progress report for the period January-March 1987. [M-cresol/quinoline/tetralin ternary mixture

    Energy Technology Data Exchange (ETDEWEB)

    Yesavage, V.F.; Kidnay, A.J.

    1987-04-30

    On July 15, 1984, work was initiated on a program to study the enthalpy and phase behavior of coal derived liquid model compound mixtures. The objectives of this program are to study the enthalpy and phase behavior of a selected ternary model compound system, representative of interactions present in coal derived liquids. Measurements will be made in a Freon 11 reference fluid boil-off calorimeter, and an equilibrium flash vaporization apparatus. These experimental systems have already been developed. Previous studies have indicated that existing data and correlations developed for petroleum fluids are not applicable to coal derived liquids. This is due to the presence of significant concentrations of polar associating heteroatomics in the predominantly aromatic coal liquids. Thus, the ternary system will include an aromatic, a basic nitrogen compound, and a cresol. It is presently planned to study the m-cresol/quinoline/tetralin ternary mixture. Measurements will be made over a wide range of temperature (200 to 750/sup 0/F) and pressure (20 to 1500 psia), for the three pure compounds, the three binary mixtures and selected compositions of the ternary. Both enthalpy and phase behavior measurements will be made. This set of data will be useful as a standard for fitting and evaluating thermodynamic correlations and equations of state that are applicable to associating fluid mixtures, and thus to coal derived liquids. In particular we will attempt to fit both the enthalpy and phase behavior data with a single equation of state using local composition mixing rules and common interaction parameters. During the eleventh quarter, enthalpy measurements have been obtained for the ternary mixtures of m-cresol/quinoline/tetralin with molar ratios 2/3:1/6:1/6 and 1/6:2/3:1/6 m-cresol:quinoline:tetralin. The results are presented in Appendix A. The project has progressed very will during this quarter, and the enthalpy measurements have been completed. 2 refs., 2 figs., 2 tabs.

  4. Phase field crystal modeling of ternary solidification microstructures

    OpenAIRE

    Berghoff, Marco; Nestler, Britta

    2015-01-01

    In the present work, we present a free energy derivation of the multi-component phase-field crystal model [1] and illustrate the capability to simulate dendritic and eutectic solidification in ternary alloys. Fast free energy minimization by a simulated annealing algorithm of an approximated crystal is compared with the free energy of a fully simulated phase field crystal structure. The calculation of ternary phase diagrams from these free energies is described. Based on the free energies rel...

  5. Subarrayed Antenna Array Synthesis Using Ternary Adjusting Method

    Directory of Open Access Journals (Sweden)

    Guolong He

    2014-01-01

    Full Text Available Ternary adjusting method is proposed and combined with particle swarm optimization (PSO algorithm for subarrayed antenna array synthesis. Ternary variables are introduced to represent element adjustments between adjacent subarrays. Compared to previous methods, rounding-off operations are not required any longer, and the equation constraint of the fixed total element number is also removed, which effectively reduces the complexity of implementation while obtaining improved topology exploration capability simultaneously.

  6. Charge distribution in the ternary fragmentation of {sup 252}Cf

    Energy Technology Data Exchange (ETDEWEB)

    Senthil Kannan, M.T.; Balasubramaniam, M. [Bharathiar University, Department of Physics, Coimbatore (India)

    2017-08-15

    We present here, for the first time, a study on ternary fragmentation charge distribution of {sup 252}Cf using the convolution integral method and the statistical theory. The charge distribution for all possible charge combinations of a ternary breakup are grouped as a bin containing different mass partitions. Different bins corresponding to various third fragments with mass numbers from A{sub 3} = 16 to 84 are identified with the available experimental masses. The corresponding potential energy surfaces are calculated using the three cluster model for the two arrangements A{sub 1} + A{sub 2} + A{sub 3} and A{sub 1} + A{sub 3} + A{sub 2}. The ternary fragmentation yield values are calculated for the ternary combination from each bin possessing minimum potential energy. The yields of the resulting ternary combinations as a function of the charge numbers of the three fragments are analyzed for both the arrangements. The calculations are carried out at different excitation energies of the parent nucleus. For each excitation energy the temperature of the three fragments are iteratively computed conserving the total energy. The distribution of fragment temperatures corresponding to different excitation energies for some fixed third fragments are discussed. The presence of the closed shell nucleus Sn in the favourable ternary fragmentation is highlighted. (orig.)

  7. Impact of ternary blends of biodiesel on diesel engine performance

    Directory of Open Access Journals (Sweden)

    Prem Kumar

    2016-06-01

    Full Text Available The Pongamia and waste cooking oils are the main non edible oils for biodiesel production in India. The aim of the present work is to evaluate the fuel properties and investigate the impact on engine performance using Pongamia and waste cooking biodiesel and their ternary blend with diesel. The investigation of the fuel properties shows that Pongamia biodiesel and waste cooking biodiesel have poor cold flow property. This will lead to starting problem in the engine operation. To overcome this problem the ternary blends of diesel, waste cooking biodiesel and Pongamia biodiesel are prepared. The cloud and pour point for ternary blend, (WCB20:PB20:D60 were found to be 7 °C and 6.5 °C which are comparable to cloud and pour point of diesel 6 °C and 5 °C, respectively. The result of the test showed that brake specific fuel consumption for Pongamia biodiesel and waste cooking biodiesel is higher than ternary blend, (WCB20:PB20:D60 due to their lower energy content. The brake thermal efficiency of ternary blend and diesel is comparable while the Pongamia and waste cooking biodiesel have low efficiency. The result of investigation showed that ternary blend can be developed as alternate fuel.

  8. Amphiphilic Molecular Motors for Responsive Aggregation in Water.

    Science.gov (United States)

    van Dijken, Derk Jan; Chen, Jiawen; Stuart, Marc C A; Hou, Lili; Feringa, Ben L

    2016-01-20

    The novel concept of amphiphilic molecular motors that self-assemble into responsive supramolecular nanotubes in water is presented. The dynamic function of the molecular motor units inside the supramolecular assemblies was studied using UV-vis absorption spectroscopy and cryo-transmission electron microscopy (cryo-TEM) microscopy. Reorganization between distinct, well-defined nanotubes and vesicles can be reversibly induced by light, going through the rotation cycle of the motor, i.e. driven by alternate photochemical and thermal isomerization steps in the system. This is the first example in which a molecular rotary motor shows self-assembly in an aqueous medium with full retention of its functionality, paving the way to increasingly complex, highly dynamic artificial nanosystems in water.

  9. New amphiphilic aminosaccharide derivatives as chiral selectors in capillary electrophoresis.

    Science.gov (United States)

    Horimai, T; Arai, T; Sato, Y

    2000-04-14

    Two amphiphilic aminosaccharide derivatives were investigated as chiral selector additives in capillary electrophoresis. Each substance has a glucosamine backbone carrying three hydrocarbon chains as the hydrophobic region and three carboxylic groups as the hydrophilic region, which is an artificial biologically active compound. Using each compound as a chiral selector, the optical resolution of dansylated amino acids or new quinolone antibacterial agents (NQs) was observed. Increasing the concentration of the chiral selector or the ionic strength of running solution led to successful optical resolution. In consideration of the chemical structure of each selector and the migration behavior of the enantiomers, the resolution seemed to be based on micellar electrokinetic chromatography mode. Both selectors differed in their enantioselectivity for dansylated amino acids or NQs although the chemical structures were similar.

  10. Amphiphilic siderophore production by oil-associating microbes.

    Science.gov (United States)

    Kem, Michelle P; Zane, Hannah K; Springer, Stephen D; Gauglitz, Julia M; Butler, Alison

    2014-06-01

    The Deepwater Horizon oil spill in 2010 released an unprecedented amount of oil into the ocean waters of the Gulf of Mexico. As a consequence, bioremediation by oil-degrading microbes has been a topic of increased focus. One factor limiting the rate of hydrocarbon degradation by microbial communities is the availability of necessary nutrients, including iron. The siderophores produced from two Vibrio spp. isolated from the Gulf of Mexico following the Deepwater Horizon oil spill, along with the well-studied oil-degrading microbe, Alcanivorax borkumensis SK2, are studied under iron-limiting conditions. Here we report the amphiphilic amphibactin siderophores produced by the oil-associated bacteria, Vibrio sp. S1B, Vibrio sp. S2A and Alcanivorax borkumensis SK2. These findings provide insight into oil-associating microbial iron acquisition.

  11. Modification of carbon nanotubes by amphiphilic glycosylated proteins.

    Science.gov (United States)

    Fang, W; Linder, M B; Laaksonen, P

    2018-02-15

    Precise organization of nanomaterials with functional biomolecules play a key role in many natural materials. In this work, single-walled carbon nanotubes were functionalized by a self-assembling amphiphilic protein that enabled their dispersion into nanofibrillated cellulose matrix. The protein contained a hydrophobic patch and a glycosylated domain and due to its dual functionality, it was able to assemble at the interface of the carbon nanotubes and the nanofibrillated cellulose and thus enhance the interactions between them. The electrical conductivity of the nanocellulose/carbon nanotube composites was improved by approximately 5-fold when the protein modified nanotubes where applied. Also improvement of the mechanical properties due to the proteins was observed. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Poly(phenylene ether Based Amphiphilic Block Copolymers

    Directory of Open Access Journals (Sweden)

    Edward N. Peters

    2017-09-01

    Full Text Available Polyphenylene ether (PPE telechelic macromonomers are unique hydrophobic polyols which have been used to prepare amphiphilic block copolymers. Various polymer compositions have been synthesized with hydrophilic blocks. Their macromolecular nature affords a range of structures including random, alternating, and di- and triblock copolymers. New macromolecular architectures can offer tailored property profiles for optimum performance. Besides reducing moisture uptake and making the polymer surface more hydrophobic, the PPE hydrophobic segment has good compatibility with polystyrene (polystyrene-philic. In general, the PPE contributes to the toughness, strength, and thermal performance. Hydrophilic segments go beyond their affinity for water. Improvements in the interfacial adhesion between polymers and polar substrates via hydrogen bonding and good compatibility with polyesters (polyester-philic have been exhibited. The heterogeneity of domains in these PPE based block copolymer offers important contributions to diverse applications.

  13. Antitumor Activity of Peptide Amphiphile Nanofiber-Encapsulated Camptothecin

    Energy Technology Data Exchange (ETDEWEB)

    Soukasene, Stephen; Toft, Daniel J.; Moyer, Tyson J.; Lu, Hsuming; Lee, Hyung-Kun; Standley, Stephany M.; Cryns, Vincent L.; Stupp, Samuel I. (NWU)

    2012-04-02

    Self-assembling peptide amphiphile (PA) nanofibers were used to encapsulate camptothecin (CPT), a naturally occurring hydrophobic chemotherapy agent, using a solvent evaporation technique. Encapsulation by PA nanofibers was found to improve the aqueous solubility of the CPT molecule by more than 50-fold. PAs self-assembled into nanofibers in the presence of CPT as demonstrated by transmission electron microscopy. Small-angle X-ray scattering results suggest a slight increase in diameter of the nanofiber to accommodate the hydrophobic cargo. In vitro studies using human breast cancer cells show an enhancement in antitumor activity of the CPT when encapsulated by the PA nanofibers. In addition, using a mouse orthotopic model of human breast cancer, treatment with PA nanofiber-encapsulated CPT inhibited tumor growth. These results highlight the potential of this model PA system to be adapted for delivery of hydrophobic therapies to treat a variety of diseases including cancer.

  14. Silver baits for the "miraculous draught" of amphiphilic lanthanide helicates.

    Science.gov (United States)

    Terazzi, Emmanuel; Guénée, Laure; Varin, Johan; Bocquet, Bernard; Lemonnier, Jean-François; Emery, Daniel; Mareda, Jiri; Piguet, Claude

    2011-01-03

    The axial connection of flexible thioalkyls chains of variable length (n=1-12) within the segmental bis-tridentate 2-benzimidazole-8-hydroxyquinoline ligands [L12(Cn) -2 H](2-) provides amphiphilic receptors designed for the synthesis of neutral dinuclear lanthanides helicates. However, the stoichiometric mixing of metals and ligands in basic media only yields intricate mixtures of poorly soluble aggregates. The addition of Ag(I) in solution restores classical helicate architectures for n=3, with the quantitative formation of the discrete D(3) -symmetrical [Ln(2) Ag2(L12(C3) -2 H)(3) ](2+) complexes at millimolar concentration (Ln=La, Eu, Lu). The X-ray crystal structure supports the formation of [La(2) Ag(2) (L12(C3) -2 H)(3) ][OTf](2) , which exists in the solid state as infinite linear polymers bridged by S-Ag-S bonds. In contrast, molecular dynamics (MD) simulations in the gas phase and in solution confirm the experimental diffusion measurements, which imply the formation of discrete molecular entities in these media, in which the sulfur atoms of each lipophilic ligand are rapidly exchanged within the Ag(I) coordination sphere. Turned as a predictive tool, MD suggests that this Ag(I) templating effect is efficient only for n=1-3, while for n>3 very loose interactions occur between Ag(I) and the thioalkyl residues. The subsequent experimental demonstration that only 25 % of the total ligand speciation contributes to the formation of [Ln(2) Ag(2) (L12(C12) -2 H)(3) ](2+) in solution puts the bases for a rational approach for the design of amphiphilic helical complexes with predetermined molecular interfaces. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Antifungal amphiphilic aminoglycoside K20: bioactivities and mechanism of action

    Directory of Open Access Journals (Sweden)

    Sanjib K. Shrestha

    2014-12-01

    Full Text Available K20 is a novel amphiphilic antifungal aminoglycoside that is synthetically derived from the antibiotic kanamycin A. Reported here are investigations of K20’s antimicrobial activities, cytotoxicity, and fungicidal mechanism of action. In vitro growth inhibitory activities against a variety of human and plant pathogenic yeasts, filamentous fungi, and bacteria were determined using microbroth dilution assays and time-kill curve analyses, and hemolytic and animal cell cytotoxic activities were determined. Effects on Cryptococcus neoformans H-99 infectivity were determined with a preventive murine lung infection model. The antifungal mechanism of action was studied using intact fungal cells, yeast lipid mutants, and small unilamellar lipid vesicles. K20 exhibited broad-spectrum in vitro antifungal activities but not antibacterial activities. Pulmonary, single dose-administration of K20 reduced C. neoformans lung infection rates 4-fold compared to controls. Hemolysis and half-maximal cytotoxicities of mammalian cells occurred at concentrations that were 10 to 32-fold higher than fungicidal MICs. With fluorescein isothiocyanate, 20 to 25 mg/L K20 caused staining of >95% of C. neoformans and Fusarium graminearum cells and at 31.3 mg/L caused rapid leakage (30 to 80% in 15 min of calcein from preloaded small unilamellar lipid vesicles. K20 appears to be a broad-spectrum fungicide, capable of reducing the infectivity of C. neoformans, and exhibits low hemolytic activity and mammalian cell toxicity. It perturbs the plasma membrane by mechanisms that are lipid modulated. K20 is a novel amphiphilic aminoglycoside amenable to scalable production and a potential lead antifungal for therapeutic and crop protection applications.

  16. Water hydrogen bond dynamics in aqueous solutions of amphiphiles.

    Science.gov (United States)

    Stirnemann, Guillaume; Hynes, James T; Laage, Damien

    2010-03-04

    The hydrogen bond dynamics of water in a series of amphiphilic solute solutions are investigated through simulations and analytic modeling with an emphasis on the interpretation of experimentally accessible two-dimensional infrared (2D IR) photon echo spectra. We evidence that for most solutes the major effect in the hydration dynamics comes from the hydrophilic groups. These groups can retard the water dynamics much more significantly than can hydrophobic groups by forming strong hydrogen bonds with water. By contrast, hydrophobic groups are shown to have a very moderate effect on water hydrogen bond breaking kinetics. We also present the first calculation of the 2D IR spectra for these solutions. While 2D IR spectroscopy is a powerful technique to probe water hydrogen bond network fluctuations, interpretations of aqueous solution spectra remain ambiguous. We show that a complementary approach through simulations and calculation of the spectra lifts the ambiguity and provides a clear connection between the simulated molecular picture and the experimental spectroscopy data. For amphiphilic solute solutions, we show that, in contrast with techniques such as NMR or ultrafast anisotropy, 2D IR spectroscopy can discriminate between waters next to the solutes hydrophobic and hydrophilic groups. We also evidence that the water dynamics slowdown due to the hydrophilic groups is dramatically enhanced in the 2D IR spectral relaxation, because these groups can induce a slow chemical exchange with the bulk, even when recognized exchange signatures are absent. Implications for the understanding of water around chemically heterogeneous systems such as protein surfaces and for the interpretation of 2D IR spectra in these cases are discussed.

  17. A ternary age-mixing model to explain contaminant occurrence in a deep supply well.

    Science.gov (United States)

    Jurgens, Bryant C; Bexfield, Laura M; Eberts, Sandra M

    2014-09-01

    The age distribution of water from a public-supply well in a deep alluvial aquifer was estimated and used to help explain arsenic variability in the water. The age distribution was computed using a ternary mixing model that combines three lumped parameter models of advection-dispersion transport of environmental tracers, which represent relatively recent recharge (post-1950s) containing volatile organic compounds (VOCs), old intermediate depth groundwater (about 6500 years) that was free of drinking-water contaminants, and very old, deep groundwater (more than 21,000 years) containing arsenic above the USEPA maximum contaminant level of 10 µg/L. The ternary mixing model was calibrated to tritium, chloroflorocarbon-113, and carbon-14 (14C) concentrations that were measured in water samples collected on multiple occasions. Variability in atmospheric 14C over the past 50,000 years was accounted for in the interpretation of (14) C as a tracer. Calibrated ternary models indicate the fraction of deep, very old groundwater entering the well varies substantially throughout the year and was highest following long periods of nonoperation or infrequent operation, which occured during the winter season when water demand was low. The fraction of young water entering the well was about 11% during the summer when pumping peaked to meet water demand and about 3% to 6% during the winter months. This paper demonstrates how collection of multiple tracers can be used in combination with simplified models of fluid flow to estimate the age distribution and thus fraction of contaminated groundwater reaching a supply well under different pumping conditions. Published 2014. This article is a U.S. Government work and is in the public domain in the USA. Groundwater published by Wiley Periodicals, Inc. on behalf of National Ground Water Association.

  18. Maxwell-Stefan diffusion coefficient estimation for ternary systems: an ideal ternary alcohol system.

    Science.gov (United States)

    Allie-Ebrahim, Tariq; Zhu, Qingyu; Bräuer, Pierre; Moggridge, Geoff D; D'Agostino, Carmine

    2017-06-21

    The Maxwell-Stefan model is a popular diffusion model originally developed to model diffusion of gases, which can be considered thermodynamically ideal mixtures, although its application has been extended to model diffusion in non-ideal liquid mixtures as well. A drawback of the model is that it requires the Maxwell-Stefan diffusion coefficients, which are not based on measurable quantities but they have to be estimated. As a result, numerous estimation methods, such as the Darken model, have been proposed to estimate these diffusion coefficients. However, the Darken model was derived, and is only well defined, for binary systems. This model has been extended to ternary systems according to two proposed forms, one by R. Krishna and J. M. van Baten, Ind. Eng. Chem. Res., 2005, 44, 6939-6947 and the other by X. Liu, T. J. H. Vlugt and A. Bardow, Ind. Eng. Chem. Res., 2011, 50, 10350-10358. In this paper, the two forms have been analysed against the ideal ternary system of methanol/butan-1-ol/propan-1-ol and using experimental values of self-diffusion coefficients. In particular, using pulsed gradient stimulated echo nuclear magnetic resonance (PGSTE-NMR) we have measured the self-diffusion coefficients in various methanol/butan-1-ol/propan-1-ol mixtures. The experimental values of self-diffusion coefficients were then used as the input data required for the Darken model. The predictions of the two proposed multicomponent forms of this model were then compared to experimental values of mutual diffusion coefficients for the ideal alcohol ternary system. This experimental-based approach showed that the Liu's model gives better predictions compared to that of Krishna and van Baten, although it was only accurate to within 26%. Nonetheless, the multicomponent Darken model in conjunction with self-diffusion measurements from PGSTE-NMR represents an attractive method for a rapid estimation of mutual diffusion in multicomponent systems, especially when compared to exhaustive

  19. Oxidized potato starch based thermoplastic films : Effect of combination of hydrophilic and amphiphilic plasticizers

    NARCIS (Netherlands)

    Niazi, Muhammad Bilal Khan; Broekhuis, Antonius A.

    Different combinations of hydrophilic (glycerol and water) and amphiphilic (isoleucine) plasticizers were studied in the production of thermoplastic starch (TPS) powders and films from oxidized potato starch. All powder samples had an irregular and shrivelled morphology. In all mixtures containing

  20. Super-resolution imaging of self-assembly of amphiphilic photoswitchable macrocycles.

    Science.gov (United States)

    Hua, Qiong-Xin; Xin, Bo; Xiong, Zu-Jing; Gong, Wen-Liang; Li, Chong; Huang, Zhen-Li; Zhu, Ming-Qiang

    2017-02-28

    Self-assembly of an amphiphilic photoswitchable fluorescent macrocycle methoxy-tetraethylene glycol-substituted hexaarylbiimidazole-borondipyrromethene can be observed directly under a super-resolution fluorescence microscope, with the nanoscale resolution beyond the optical diffraction limitation.

  1. Self-assembling peptide amphiphiles and related methods for growth factor delivery

    Energy Technology Data Exchange (ETDEWEB)

    Stupp, Samuel I; Donners, Jack J.J.M.; Silva, Gabriel A; Behanna, Heather A; Anthony, Shawn G

    2013-11-12

    Amphiphilic peptide compounds comprising one or more epitope sequences for binding interaction with one or more corresponding growth factors, micellar assemblies of such compounds and related methods of use.

  2. Self-assembling peptide amphiphiles and related methods for growth factor delivery

    Science.gov (United States)

    Stupp, Samuel I [Chicago, IL; Donners, Jack J. J. M.; Silva, Gabriel A [Chicago, IL; Behanna, Heather A [Chicago, IL; Anthony, Shawn G [New Stanton, PA

    2012-03-20

    Amphiphilic peptide compounds comprising one or more epitope sequences for binding interaction with one or more corresponding growth factors, micellar assemblies of such compounds and related methods of use.

  3. Amniotic fluid

    Science.gov (United States)

    ... or movements Too much amniotic fluid is called polyhydramnios . This condition can occur with multiple pregnancies (twins ... development of the fetus. Images Amniocentesis Amniotic fluid Polyhydramnios Amniotic fluid References Burton GJ, Sibley CP, Jauniaux ...

  4. Amphiphilic polymer based on fluoroalkyl and PEG side chains for fouling release coating

    Science.gov (United States)

    Cong, W. W.; Wang, K.; Yu, X. Y.; Zhang, H. Q.; Lv, Z.; Gui, T. J.

    2017-12-01

    Under static conditions, fouling release coating could not express good release property to marine organisms. Amphiphilic polymer with mixture of fluorinated monomer and short side group of polyethylene glycol (PEG) was synthesized. And also we studied the ability of amphiphilic polymer to influence the surface properties and how it controlled the adhesion of marine organisms to coated surfaces. By incorporating fluorinated monomer and PEG side chain into the polymer, the effect of incorporating both polar and non-polar groups on fouling-release coating could be studied. The dry surface was characterized by three-dimensional digital microscopy and scanning electron microscopy (SEM), and the morphology of the amphiphilic fouling release coating showed just like flaky petal. The amphiphilic polymer in fouling release coating tended to reconstruct in water, and the ability was examined by static contact angle, which was smaller than the PDMS (polydimethylsiloxane) fouling release coating. Also surface energy was calculated by three solvents, and surface energy of amphiphilic fouling release coating was higher than that of the PDMS fouling release coating. To understand more about its fouling release property, seawater exposure method was adopted in gulf of Qingdao port. Fewer diatoms Navicula were found in biofilm after using amphiphilic fouling release coating. In general, coating containing both PEG and fluorinated side chain possessed certain fouling release property.

  5. Analysis of cutoff frequency in one dimensional ternary superconducting photonic crystal

    Science.gov (United States)

    K. P., Sreejith; Maria D'souza, Nirmala; Mathew, Vincent

    2017-09-01

    By means of two fluid model and transfer matrix method, we have theoretically investigated the transmittance property of a one dimensional ternary photonic crystal consist of a pair of superconducting materials and a dielectric in the infrared frequency region. We mainly focus on the analysis of cutoff frequency since the calculations can be useful in the fabrication of optical devices such as reflector, high pass filter etc. The study reveals that the cutoff frequency is sensitive to thickness of superconducting materials, dielectric layer thickness, operating temperature and refractive index of intermediate dielectric. Cutoff frequency shifted to higher frequency region on increasing number of periods and superconductor layer thickness where as it reduces on increasing dielectric thickness, operating temperature and refractive index of intermediate dielectric. Furthermore, we compared the cutoff frequency of three different 1D ternary photonic crystals comprising of a dielectric and a pair of high-high, high-low and low-low temperature superconducting materials. Our comparison results shows that the cutoff frequency can be effectively modified with different combination of superconducting materials.

  6. Two-layer synchronized ternary quantum-dot cellular automata wire crossings

    Science.gov (United States)

    2012-01-01

    Quantum-dot cellular automata are an interesting nanoscale computing paradigm. The introduction of the ternary quantum-dot cell enabled ternary computing, and with the recent development of a ternary functionally complete set of elementary logic primitives and the ternary memorizing cell design of complex processing structures is becoming feasible. The specific nature of the ternary quantum-dot cell makes wire crossings one of the most problematic areas of ternary quantum-dot cellular automata circuit design. We hereby present a two-layer wire crossing that uses a specific clocking scheme, which ensures the crossed wires have the same effective delay. PMID:22507371

  7. Visualization and microrheology of complex fluid/fluid interfaces

    Science.gov (United States)

    Choi, Siyoung Q.; Zasadzinski, Joseph; Squires, Todd

    2009-11-01

    We describe a novel microrheological technique to measure the rheological properties of fluid/fluid interfaces, which can dramatically affect the flow properties and dynamics of multiphase materials (emulsions, foams, cells and organs). Such measurements can be particularly challenging, as one needs to measure the influence of molecularly thin, two-dimensional layers but be insensitive to the three-dimensional bulk fluids on either side. However, dimensionality helps here: interfacial forces on a probe are exerted along a contact perimeter, whereas the bulk forces are exerted on the contact area. Smaller probes thus increase the perimeter/area ratio, and therefore the relative sensitivity to interfacial viscoelasticity. We fabricate micron-scale ferromagnetic amphiphilic disks (with versatile surface chemistry), place them on the interface, use external electromagnets to exert a known torque (stress), and measure the resulting rotational displacement (strain). In addition to its sensitivity, our technique can measure frequency dependent linear/nonlinear viscoelastic properties and yield stresses. Simultaneous visualization of the interface by fluorescence microscopy allows us to correlate local dynamics withe measured rheology. We validate our technique and highlight its capabilities with measurements on a variety of systems, including two-dimensional colloidal monolayers, fatty acid and phospholipid monolayers.

  8. Modelling of volumetric properties of binary and ternary mixtures by CEOS, CEOS/GE and empirical models

    Directory of Open Access Journals (Sweden)

    BOJAN D. DJORDJEVIC

    2007-12-01

    Full Text Available Although many cubic equations of state coupled with van der Waals-one fluid mixing rules including temperature dependent interaction parameters are sufficient for representing phase equilibria and excess properties (excess molar enthalpy HE, excess molar volume VE, etc., difficulties appear in the correlation and prediction of thermodynamic properties of complex mixtures at various temperature and pressure ranges. Great progress has been made by a new approach based on CEOS/GE models. This paper reviews the last six-year of progress achieved in modelling of the volumetric properties for complex binary and ternary systems of non-electrolytes by the CEOS and CEOS/GE approaches. In addition, the vdW1 and TCBT models were used to estimate the excess molar volume VE of ternary systems methanol + chloroform + benzene and 1-propanol + chloroform + benzene, as well as the corresponding binaries methanol + chloroform, chloroform + benzene, 1-propanol + chloroform and 1-propanol + benzene at 288.15–313.15 K and atmospheric pressure. Also, prediction of VE for both ternaries by empirical models (Radojković, Kohler, Jackob–Fitzner, Colinet, Tsao–Smith, Toop, Scatchard, Rastogi was performed.

  9. High pressure phase equilibrium of ternary and multicomponent alkane mixtures in the temperature range from (283–473) K

    DEFF Research Database (Denmark)

    Regueira Muñiz, Teresa; Liu, Yiqun; Wibowo, Ahmad A.

    2017-01-01

    Asymmetric multicomponent alkane mixtures can be used as model systems for reservoir fluids. We have prepared two ternary mixtures, methane/n-butane/n-decane and methane/n-butane/n-dodecane, and two multicomponent mixtures composed of methane/n-butane/n-octane/n-dodecane/n-hexadecane/n-eicosane a......Asymmetric multicomponent alkane mixtures can be used as model systems for reservoir fluids. We have prepared two ternary mixtures, methane/n-butane/n-decane and methane/n-butane/n-dodecane, and two multicomponent mixtures composed of methane......-Redlich-Kwong (SRK), Peng-Robinson (PR), Perturbed Chain Statistical Associating Fluid Theory (PC-SAFT), and Soave-Benedict-Webb-Rubin (Soave-BWR), have been used to predict phase equilibrium of the measured systems. PR and PC-SAFT give better results than others and Soave-BWR gives poor phase envelope predictions...... the fractions just below the saturation pressures are difficult to predict. Moreover GERG-2008 has also been tested with the measured methane/n-butane/n-decane system. It over predicts the saturation pressures but predicts low pressure liquid fractions quite accurately....

  10. Liquid-liquid equilibria for ternary polymer mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Suk Yung [Division of Chemical Engineering and Molecular Thermodynamics Laboratory, Hanyang University, Seoul 133-791 (Korea, Republic of); Bae, Young Chan, E-mail: ycbae@hanyang.ac.kr [Division of Chemical Engineering and Molecular Thermodynamics Laboratory, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2011-01-24

    Graphical abstract: We developed a molecular thermodynamic model for multicomponent systems and discribed the phase equilibrium for ternary polymer mixtures by using the model parameters obtained from the binary systems. Research highlights: {yields} Model parameters were obtained from the binary systems. {yields} The obtained parameters were directly used to predict the ternary data. {yields} The undetermined parameters were used to correlate the ternary data. {yields} The proposed model agreed well with the experimental data. - Abstract: A molecular thermodynamic model for multicomponent systems based on a closed-packed lattice model is presented based on two contributions; entropy and energy contribution. The calculated liquid-liquid equilibria of ternary chainlike mixtures agreed with Monte Carlo simulation results. The proposed model can satisfactorily predict Types 0, 1, 2 and 3 phase separations of the Treybal classification. The model parameters obtained from the binary systems were used to directly predict real ternary systems and the calculated results correlated well with experimental data using few adjustable parameters. Specific interactions in associated binary systems were considered using a secondary lattice.

  11. Synthesis of antibacterial amphiphilic elastomer based on polystyrene-block-polyisoprene-block-polystyrene via thiol-ene addition

    Energy Technology Data Exchange (ETDEWEB)

    Keleş, Elif, E-mail: elifkelesh@hotmail.com [Department of Chemistry, Bülent Ecevit University, Zonguldak 67100 (Turkey); Hazer, Baki, E-mail: bhazer2@yahoo.com [Department of Chemistry, Bülent Ecevit University, Zonguldak 67100 (Turkey); Cömert, Füsun B. [Department of Microbiology, Faculty of Medicine, Bülent Ecevit University, 67600 Zonguldak (Turkey)

    2013-04-01

    A new type of amphiphilic antibacterial elastomer has been described. Thermoplastic elastomer, polystyrene–block-polyisoprene–block-polystyrene (PS–b-PI–b-PS) triblock copolymer was functionalized in toluene solution by free radical mercaptan addition in order to obtain an amphiphilic antibacterial elastomer. Thiol terminated PEG was grafted through the double bonds of PS–b-PI–b-PS via free radical thiol-ene coupling reaction. The antibacterial properties of the amphiphilic graft copolymers were observed. The original and the modified polymers were used to create microfibers in an electro-spinning process. Topology of the electrospun micro/nanofibers were studied by using scanning electron microscopy (SEM). The chemical structures of the amphiphilic comb type graft copolymers were elucidated by the combination of elemental analysis, {sup 1}H NMR, {sup 13}C NMR, GPC and FTIR. - Graphical abstract: Double bonds of polyisoprene units in polystyrene–block-polyisoprene–block-polystyrene triblock copolymer were partially capped with PEG containing mercapto end group via thiol-ene addition in order to obtain antibacterial amphiphilic elastomer. Nano fibers from amphiphilic graft polymers solution were produced by electrospinning. The PEG grafted copolymer inhibits very effectively bacterial growth. Highlights: ► A commercial synthetic elastomer was grafted with PEG to obtain amphiphilic elastomer. ► Amphiphilic elastomer shows antibacterial properties. ► Electrospun micro fibers of the amphiphilic elastomer tend to globular formation.

  12. Wet granular matter a truly complex fluid

    CERN Document Server

    Herminghaus, Stephan

    2013-01-01

    This is a monograph written for the young and advanced researcher who is entering the field of wet granular matter and keen to understand the basic physical principles governing this state of soft matter. It treats wet granulates as an instance of a ternary system, consisting of the grains, a primary, and a secondary fluid. After addressing wetting phenomena in general and outlining the basic facts on dry granular systems, a chapter on basic mechanisms and their effects is dedicated to every region of the ternary phase diagram. Effects of grain shape and roughness are considered as well. Rather than addressing engineering aspects such as existing books on this topic do, the book aims to provide a generalized framework suitable for those who want to understand these systems on a more fundamental basis. Readership: For the young and advanced researcher entering the field of wet granular matter.

  13. High-Pressure Phase Behavior of Polycaprolactone, Carbon Dioxide, and Dichloromethane Ternary Mixture Systems

    Energy Technology Data Exchange (ETDEWEB)

    Gwon, JungMin; Kim, Hwayong [Seoul National University, Seoul (Korea, Republic of); Shin, Hun Yong [Seoul National University of Science and Technology, Seoul (Korea, Republic of); Kim, Soo Hyun [Korea Institute of Science and Technology, Seoul (Korea, Republic of)

    2015-04-15

    The high-pressure phase behavior of a polycaprolactone (Mw=56,145 g/mol, polydispersity 1.2), dichloromethane, and carbon dioxide ternary system was measured using a variable-volume view cell. The experimental temperatures and pressures ranged from 313.15 K to 353.15 K and up to 300 bar as functions of the CO{sub 2}/dichloromethane mass ratio and temperature, at poly(D-lactic acid) weight fractions of 1.0, 2.0, and 3.0%. The correlation results were obtained from the hybrid equation of state (Peng-Robinson equation of state + SAFT equation of state) for the CO{sub 2}-polymer system using the van der Waals one-fluid mixing rule. The three binary interaction parameters were optimized by the simplex method algorithm.

  14. Completed Local Ternary Pattern for Rotation Invariant Texture Classification

    Directory of Open Access Journals (Sweden)

    Taha H. Rassem

    2014-01-01

    Full Text Available Despite the fact that the two texture descriptors, the completed modeling of Local Binary Pattern (CLBP and the Completed Local Binary Count (CLBC, have achieved a remarkable accuracy for invariant rotation texture classification, they inherit some Local Binary Pattern (LBP drawbacks. The LBP is sensitive to noise, and different patterns of LBP may be classified into the same class that reduces its discriminating property. Although, the Local Ternary Pattern (LTP is proposed to be more robust to noise than LBP, however, the latter’s weakness may appear with the LTP as well as with LBP. In this paper, a novel completed modeling of the Local Ternary Pattern (LTP operator is proposed to overcome both LBP drawbacks, and an associated completed Local Ternary Pattern (CLTP scheme is developed for rotation invariant texture classification. The experimental results using four different texture databases show that the proposed CLTP achieved an impressive classification accuracy as compared to the CLBP and CLBC descriptors.

  15. On the interpretation, verification and calibration of ternary probabilistic forecasts

    CERN Document Server

    Jupp, Tim E; Coelho, Caio A S; Stephenson, David B

    2011-01-01

    We develop a geometrical interpretation of ternary probabilistic forecasts in which forecasts and observations are regarded as points inside a triangle. Within the triangle, we define a continuous colour palette in which hue and colour saturation are defined with reference to the observed climatology. In contrast to current methods, forecast maps created with this colour scheme convey all of the information present in each ternary forecast. The geometrical interpretation is then extended to verification under quadratic scoring rules (of which the Brier Score and the Ranked Probability Score are well--known examples). Each scoring rule defines an associated triangle in which the square roots of the \\emph{score}, the \\emph{reliability}, the \\emph{uncertainty} and the \\emph{resolution} all have natural interpretations as root--mean--square distances. This leads to our proposal for a \\emph{Ternary Reliability Diagram} in which data relating to verification and calibration can be summarised. We illustrate these id...

  16. [Synthesis and luminescence properties of reactive ternary europium complexes].

    Science.gov (United States)

    Guo, Dong-cai; Shu, Wan-gen; Zhang, Wei; Liu, You-nian; Zhou, Yue

    2004-09-01

    In this paper, five new reactive ternary europium complexes were synthesized with the first ligand of 1,10-phenanthroline and the reactive second ligands of maleic anhydride, acrylonitrile, undecenoic acid, oleic acid and linoleic acid, and also characterized by means of elemental analysis, EDTA titrimetric method, FTIR spectra and UV spectra. The fluorescence spectra show that the five new ternary complexes have much higher luminescence intensity than their corresponding binary complexes, and the synergy ability sequence of the five reactive ligands is as follows: linoleic acid > oleic acid > acrylonitrile > maleic anhydride > undecenoic acid. At the same time, the reactive ternary europium complexes coordinated with the reactive ligands, which can be copolymerized with other monomers, will provide a new way for the synthesis of bonding-type rare earth polymer functional materials with excellent luminescence properties.

  17. Membrane deformation controlled by monolayer composition of embedded amphiphilic nanoparticles

    Science.gov (United States)

    van Lehn, Reid; Alexander-Katz, Alfredo

    2014-03-01

    In recent work, we have shown that charged, amphiphilic nanoparticles (NPs) can spontaneously insert into lipid bilayers, embedding the NP in a conformation resembling a transmembrane protein. Many embedded membrane proteins exert an influence on surrounding lipids that lead to deformation and membrane-mediated interactions that may be essential for function. Similarly, embedded NPs will also induce membrane deformations related to the same physicochemical forces. Unlike many transmembrane proteins, however, the highly charged NPs may exert preferential interactions on surrounding lipid head groups. In this work, we use atomistic molecular dynamics simulations to show that the membrane around embedded particles may experience local thinning, head group reorientation, and an increase in lipid density depending on the size and surface composition of the NP. We quantify the extent of these deformations and illustrate the complex interplay between lipid tail group and head group interactions that go beyond pure thickness deformations that may be expected from coarse-grained or continuum models. This work thus suggests guidelines for the design of particles that spontaneously partition into lipid bilayers and influence local membrane mechanical properties in a targeted manner.

  18. Effect of Amphiphiles on the Rheology of Triglyceride Networks

    Science.gov (United States)

    Seth, Jyoti

    2014-11-01

    Networks of aggregated crystallites form the structural backbone of many products from the food, cosmetic and pharmaceutical industries. Such materials are generally formulated by cooling a saturated solution to yield the desired solid fraction. Crystal nucleation and growth followed by aggregation leads to formation of a space percolating fractal-network. It is understood that microstructural hierarchy and particle-particle interactions determine material behavior during processing, storage and use. In this talk, rheology of suspensions of triglycerides (TAG, like tristearin) will be explored. TAGs exhibit a rich assortment of polymorphs and form suspensions that are evidently sensitive to surface modifying additives like surfactants and polymers. Here, a theoretical framework will be presented for suspensions containing TAG crystals interacting via pairwise potentials. The work builds on existing models of fractal aggregates to understand microstructure and its correlation with material rheology. Effect of amphiphilic additives is derived through variation of particle-particle interactions. Theoretical predictions for storage modulus will be compared against experimental observations and data from the literature and micro structural predictions against microscopy. Such a theory may serve as a step towards predicting short and long-term behavior of aggregated suspensions formulated via crystallization.

  19. Anti-biofouling properties of amphiphilic phosphorylcholine polymer films.

    Science.gov (United States)

    Li, Yan; Liu, Cheng-Mei; Yang, Jin-Ying; Gao, Ya-Hui; Li, Xue-Song; Que, Guo-He; Lu, J R

    2011-07-01

    Surfaces of amphiphilic phosphorylcholine polymer (PC1036) prepared by spin-coating were characterized by spectroscopic ellipsometry, water contact angle and atomic force microscopy. The antifouling properties of the PC1036 films to marine benthic diatom Nitzschia closterium MMDL533 were also investigated. The results showed that the dry PC1036 film promoted the adhesion of N. closterium MMDL533 because the hydrophobic lauryl groups were present in the film surface. The 2 h-swelled PC1036 films had excellent anti-fouling properties with extremely low attachment densities and retention densities no matter what the annealing temperature was. The thickness of the coated films lower than 147 Å had a profound effect on the film anti-fouling properties. Otherwise, when the film thickness was higher than that value, there was no more improvement of diatom cell reduction observed. The annealing temperature had only a little effect on the film resistant to diatom adhesion, which might be attributed to two factors including the PC group packing densities in the outer PC layer and the equilibrated water volume fraction in the 2 h-swelled PC1036 films. Published by Elsevier B.V.

  20. Amphiphilic star PEG-Camptothecin conjugates for intracellular targeting.

    Science.gov (United States)

    Omar, Rawan; Bardoogo, Yael Leichtman; Corem-Salkmon, Enav; Mizrahi, Boaz

    2017-07-10

    Camptothecin (CPT) is a naturally occurring cytotoxic alkaloid having a broad spectrum of antitumor activity. Unfortunately, it has low bioavailability and encapsulation efficiency, limiting its clinical use. We report on our efforts to develop a novel drug delivery prototype composed of a short, star hydrophilic polyethylene glycol (PEG) backbone and hydrophobic CPT (PEG 4 -CPT). The amphiphilic bio-conjugate self-assembles in water into stable spherical nano-particles with a mean diameter of 200nm and CPT substitution percentage of 27%w/w. CPT is released in a sustained release profile without burst effect. In addition, PEG 4 -CPT nano-particles are able to load a co-drug, water soluble or non-water soluble doxorubicin and release them simultaneously with the free CPT. The biological evaluation of PEG 4 -CPT against HeLa cells showed improved cellular uptake and enhanced cytotoxicity compared to free CPT. Thus, in this approach CPT acts in two ways: As the hydrophobic segment that enables self-assembly in water and as a potent anticancer agent. This concept of combining hydrophobic drugs and short star polymers shows great potential for efficient delivery of hydrophobic chemotrophic drugs as well as for drugs with inherent stability and pharmacokinetic barriers. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Thermodynamic Study of Sn-Bi-Nd, Tb Ternary Systems

    Science.gov (United States)

    Xu, F.; Chen, Y. T.; Ye, R.; Chen, Y. Y.; Su, X. H.; Wang, S. L.; Fu, C. Y.

    2017-09-01

    The aim of this study was to investigate the effect of the addition of rare earth elements on Sn-Bi-based alloy, and to study the phase equilibrium of Sn-Bi-Nd, Tb ternary systems by means of establishing the thermodynamic database. Combined with the thermodynamic parameters of relevant binary systems, the thermodynamic database of the Sn-Bi-Nd, Tb ternary systems has been developed to present the significant information for the design of low-temperature lead-free solder alloys.

  2. Ternary jitter-based true random number generator

    Science.gov (United States)

    Latypov, Rustam; Stolov, Evgeni

    2017-01-01

    In this paper a novel family of generators producing true uniform random numbers in ternary logic is presented. The generator consists of a number of identical ternary logic combinational units connected into a ring. All the units are provided to have a random delay time, and this time is supposed to be distributed in accordance with an exponential distribution. All delays are supposed to be independent events. The theory of the generator is based on Erlang equations. The generator can be used for test production in various systems. Features of multidimensional random vectors, produced by the generator, are discussed.

  3. Liquid-liquid equilibria for ternary polymer mixtures

    Science.gov (United States)

    Oh, Suk Yung; Bae, Young Chan

    2011-01-01

    A molecular thermodynamic model for multicomponent systems based on a closed-packed lattice model is presented based on two contributions; entropy and energy contribution. The calculated liquid-liquid equilibria of ternary chainlike mixtures agreed with Monte Carlo simulation results. The proposed model can satisfactorily predict Types 0, 1, 2 and 3 phase separations of the Treybal classification. The model parameters obtained from the binary systems were used to directly predict real ternary systems and the calculated results correlated well with experimental data using few adjustable parameters. Specific interactions in associated binary systems were considered using a secondary lattice.

  4. PM1 steganographic algorithm using ternary Hamming Code

    Directory of Open Access Journals (Sweden)

    Kamil Kaczyński

    2015-12-01

    Full Text Available PM1 algorithm is a modification of well-known LSB steganographic algorithm. It has increased resistance to selected steganalytic attacks and increased embedding efficiency. Due to its uniqueness, PM1 algorithm allows us to use of larger alphabet of symbols, making it possible to further increase steganographic capacity. In this paper, we present the modified PM1 algorithm which utilizies so-called syndrome coding and ternary Hamming code. The modified algorithm has increased embedding efficiency, which means fewer changes introduced to carrier and increased capacity.[b]Keywords[/b]: steganography, linear codes, PM1, LSB, ternary Hamming code

  5. Phases and phase transition in insoluble and adsorbed monolayers of amide amphiphiles: Specific characteristics of the condensed phases.

    Science.gov (United States)

    Vollhardt, D

    2015-08-01

    For understanding the role of amide containing amphiphiles in inherently complex biological processes, monolayers at the air-water interface are used as simple biomimetic model systems. The specific characteristics of the condensed phases and phase transition in insoluble and adsorbed monolayers of amide amphiphiles are surveyed to highlight the effect of the chemical structure of the amide amphiphiles on the interfacial interactions in model monolayers. The mesoscopic topography and/or two-dimensional lattice structures of selected amino acid amphiphiles, amphiphilic N-alkylaldonamide, amide amphiphiles with specific tailored headgroups, such as amide amphiphiles based on derivatized ethanolamine, e.g. acylethanolamines (NAEs) and N-,O-diacylethanolamines (DAEs) are presented. Special attention is devoted the dominance of N,O-diacylated ethanolamine in mixed amphiphilic acid amide monolayers. The evidence that a first order phase transition can occur in adsorption layers and that condensed phase domains of mesoscopic scale can be formed in adsorption layers was first obtained on the basis of the experimental characteristics of a tailored amide amphiphile. New thermodynamic and kinetic concepts for the theoretical description of the characteristics of amide amphiphile's monolayers were developed. In particular, the equation of state for Langmuir monolayers generalized for the case that one, two or more phase transitions occur, and the new theory for phase transition in adsorbed monolayers are experimentally confirmed at first by amide amphiphile monolayers. Despite the significant progress made towards the understanding the model systems, these model studies are still limited to transfer the gained knowledge to biological systems where the fundamental physical principles are operative in the same way. The study of biomimetic systems, as described in this review, is only a first step in this direction. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. The ternary system: silicon-uranium-vanadium

    Energy Technology Data Exchange (ETDEWEB)

    Noel, Henri [Laboratoire de Chimie du Solide et Materiaux, UMR-CNRS 6226, Universite de Rennes I, Avenue du General Leclerc, F-35042 Rennes, Cedex (France); Rogl, Peter Franz, E-mail: peter.franz.rogl@univie.ac.a [Institute of Physical Chemistry, University of Vienna, A-1090 Wien, Waehringerstrasse 42 (Austria)

    2010-09-01

    Phase equilibria in the system Si-U-V were established at 1100 {sup o}C by optical microscopy, EMPA and X-ray diffraction. Two ternary compounds were observed, U{sub 2}V{sub 3}Si{sub 4} and (U{sub 1-x}V{sub x}){sub 5}Si{sub 3}, for which the crystal structures were elucidated by X-ray powder data refinement and found to be isotypic with the monoclinic U{sub 2}Mo{sub 3}Si{sub 4}-type (space group P2{sub 1}/c; a = 0.6821(3), b = 0.6820(4), c = 0.6735(3) nm, {beta} = 109.77(1){sup o}) and the tetragonal W{sub 5}Si{sub 3}-type (space group I4/mcm, a = 1.06825(2), c = 0.52764(2) nm), respectively. (U{sub 1-x}V{sub x}){sub 5}Si{sub 3} appears at 1100 {sup o}C without any significant homogeneity region at x {approx} 0.2 resulting in a formula U{sub 4}VSi{sub 3} which corresponds to a fully ordered atom arrangement. DTA experiments clearly show decomposition of this phase above 1206 {sup o}C revealing a two-phase region U{sub 3}Si{sub 2} + V{sub 3}Si. At 1100 {sup o}C U{sub 4}VSi{sub 3} is in equilibrium with V{sub 3}Si, V{sub 5}Si{sub 3}, U{sub 3}Si{sub 2} and U(V). At 800 {sup o}C U{sub 4}VSi{sub 3} forms one vertex of the tie-triangle to U{sub 3}Si and V{sub 3}Si. Due to the rather high thermodynamic stability of V{sub 3}Si and the corresponding tie-lines V{sub 3}Si + liquid at 1100 {sup o}C and V{sub 3}Si + U(V) below 925 {sup o}C, no compatibility exists between U{sub 3}Si or U{sub 3}Si{sub 2} and vanadium metal.

  7. Antibacterial activities and bonding of MMSA/TBB resin containing amphiphilic lipids.

    Science.gov (United States)

    Kazuno, Taichi; Fukushima, Tadao; Hayakawa, Tohru; Inoue, Yusuke; Ogura, Rieko; Kaminishi, Hidenori; Miyazaki, Koji

    2005-06-01

    The purpose of this study was to investigate the antibacterial activity of MMA/TBB resin containing newly developed amphiphilic lipids. The amphiphilic lipids, C10-L-Ala/pts and C12-L-Ala/pts, synthesized from the reaction of n-alkyl alcohol and L-alanine were dissolved in MMA at concentrations of 0.5, 1.0, 1.5, and 2.0 mol%. Resin mixtures of PMMA powder and each MMA liquid containing lipid and TBB were prepared for all tests. Both lipids gave antibacterial effect to MMA/ TBB resin. The addition of C12-L-Ala/pts to MMA resulted in a significantly higher antibacterial activity than the addition of C10-L-Ala/pts. In terms of bond strength, the bond strength of MMA/TBB resin to bovine dentin was significantly decreased by the addition of amphiphilic lipids. But for enamel, the bond strength of MMA/TBB resin with amphiphilic lipids was clinically acceptable for orthodontic brackets. In conclusion, amphiphilic lipids will be useful as a component of adhesive resin to give the latter an antibacterial effect.

  8. Cationic Amphiphiles Increase Activity of Aminoglycoside Antibiotic Tobramycin in the Presence of Airway Polyelectrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Purdy Drew, Kirstin R.; Sanders, Lori K.; Culumber, Zachary W.; Zribi, Olena; Wong, Gerard C.L.; (UIUC)

    2009-06-17

    It is empirically known that anionic polyelectrolytes present in cystic fibrosis (CF) airways due to bacterial infection significantly decrease the activity of cationic antimicrobials via electrostatic binding. In this work, we use synchrotron small-angle X-ray scattering to investigate the interaction between tobramycin, an aminoglycoside antibiotic commonly administered to CF patients via inhalation, with DNA, which is found in high concentrations in the CF airway. We find that interactions between DNA and tobramycin are significantly modified by the presence of mixtures of amphiphilic molecules. We measure a hierarchy of self-assembled structures formed between tobramycin, DNA, and the amphiphile mixtures and show how interactions between these components can be controlled. Results indicate that mixtures of cationic and negative curvature amphiphiles optimized for DNA binding via charge matching and curvature matching can competitively displace bound tobramycin from DNA and thereby drastically suppress tobramycin-DNA binding and resultant antimicrobial inactivation. Growth inhibition assays confirm the increased activity of tobramycin in the presence of DNA with the addition of the amphiphiles. These results suggest that optimized cationic amphiphile solutions have the potential to enhance antimicrobial function in highly infected environments that contain increased concentrations of anionic inflammatory polymers.

  9. Absorption fluids data survey: Final report on foreign data

    Energy Technology Data Exchange (ETDEWEB)

    Macriss, R.A.; Gutraj, J.M.; Zawacki, T.S.

    1987-04-01

    In a 12-month evaluation, 300 different foreign publications containing data that relate to properties of binary, ternary, and multicomponent absorption fluids were identified; from these publications, 127 were selected as sources of relevant foreign data. Fluids covered include combinations of each of 20 different refrigerant compounds, with one or more of 41 single, 13 binary, and 6 ternary absorbent compounds. Generally, the 20 refrigerants are divided among the following categories of chemical compounds - INORGANIC 2, ORGANIC 18 (amines 2, alcohols 5, halogenated 10 and hydrocarbons 1). Likewise, the single absorbent compounds generally are subdivided as follows - INORGANIC 11, ORGANIC 30 (alcohols 7, ethers 4, alcohol-ethers 1, amides 2, amines 1, esters 7, ketones 2, acids 1 and others 5). The binary and ternary absorbents are various mixtures of two or more single absorbent compounds. Coarse screening and evaluations were performed. Data gaps for key fluids are summarized and unresolved conflicts in data are noted. Results show that with very few exceptions, all candidate fluids for development activities dealing with advanced absorption heat pump concepts have data gaps that must be addressed in the near future.

  10. Absorption fluids data survey: Final report on worldwide data

    Energy Technology Data Exchange (ETDEWEB)

    Macriss, R.A.; Gutraj, J.M.; Zawacki, T.S.

    1988-02-01

    Over 500 different worldwide publications containing data that relate to properties of binary, ternary, and multicomponent absorption fluids have been identified; from these publications, 278 were selected as primary sources of relevant data. Fluids covered include combinations of 38 different refrigerant compounds, as well as of 131 single, 42 binary, and 14 ternary absorbent compounds. Generally, the 38 refrigerants are divided among the following categories of chemical compounds: inorganic, 3; organic, 35 (amines, 4; alcohols, 5; halogenated, 25; and hydrocarbons, 1). The single absorbent compounds generally are subdivided as follows: inorganic, 48; organic, 83 (alcohols, 10; ethers, 5; alcohol-ethers, 3; amides, 9; amines, 4; amine-alcohols, 1; esters, 21; ketones, 5; acids, 4; aldehydes, 1; and others, 20). The binary and ternary absorbents are various mixtures of two or more single absorbent compounds. Coarse screening and evaluations were performed. Data gaps for key fluids are summarized and unresolved conflicts in data are noted. Results show that, with very few exceptions, all candidate fluids for development activities dealing with advanced absorption heat pump concepts have data gaps that must be addressed in the near future. 44 figs., 6 tabs.

  11. Absorption fluids data survey: final report on USA data

    Energy Technology Data Exchange (ETDEWEB)

    Macriss, R.A.; Zawacki, T.S.

    1986-05-01

    In an 8-month evaluation, 150 different US publications containing data that relate to properties of binary, ternary, and multicomponent absorption fluids were identified; from these publications, 67 were selected as primary sources of relevant US data. Fluids covered include combinations of 25 different refrigerant compounds, as well as of 67 single, 30 binary, and 4 ternary absorbent compounds. Generally, the 25 refrigerants are divided among the following categories of chemical compounds - INORGANIC 3, ORGANIC 22 (amines 3, alcohols 3, halogenated 16). Likewise, the single absorbent compounds generally are subdivided as follows - INORGANIC 31, ORGANIC 48 (alcohols 6, ethers 5, alcohol-ethers 2, amines 8, amines 3, amine-alcohol 1, esters 9, ketones 5, acids 3, aldehyde 1, others 4). The binary and ternary absorbents are various mixtures of two or more single absorbent compounds. Coarse screening and evaluations were performed. Data gaps for key fluids are summarized and unresolved conflicts in data are noted. Results show that, with very few exceptions, all candidate fluids for development activities dealing with advanced absorption heat pump concepts have data gaps that must be addressed in the near future.

  12. Fluid Mechanics.

    Science.gov (United States)

    Drazin, Philip

    1987-01-01

    Outlines the contents of Volume II of "Principia" by Sir Isaac Newton. Reviews the contributions of subsequent scientists to the physics of fluid dynamics. Discusses the treatment of fluid mechanics in physics curricula. Highlights a few of the problems of modern research in fluid dynamics. Shows that problems still remain. (CW)

  13. Fluid Interfaces

    DEFF Research Database (Denmark)

    Hansen, Klaus Marius

    2001-01-01

    Fluid interaction, interaction by the user with the system that causes few breakdowns, is essential to many user interfaces. We present two concrete software systems that try to support fluid interaction for different work practices. Furthermore, we present specificity, generality, and minimality...... as design goals for fluid interfaces....

  14. Studies on Molecular Interaction in Ternary Liquid Mixtures

    Directory of Open Access Journals (Sweden)

    R. Uvarani

    2010-01-01

    Full Text Available Ultrasonic velocity, density and viscosity for the ternary liquid mixtures of cyclohexanone with 1-propanol and 1-butanol in carbon tetrachloride were measured at 303 K. The acoustical parameters and their excess values were calculated. The trends in the variation of these excess parameters were used to discuss the nature and strength of the interactions present between the component molecules.

  15. Hierarchic structure formation in binary and ternary polymer blends

    NARCIS (Netherlands)

    Sprenger, M; Walheim, S; Budkowski, A; Steiner, U

    The phase morphology of multi-component polymer blends is governed by the interfacial interactions of its components. We discuss here the domain morphology in thin films of model binary and ternary polymer blends containing polystyrene, poly(methyl metacrylate), and poly(2-vinylpyridine) (PS, PMMA,

  16. Mechanical, microstructure and electrical properties of ternary ZnO ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 38; Issue 3. Mechanical, microstructure and electrical properties of ternary ZnO–V2O5–Mn3O4 varistor with sintering temperature. S El-Rabai A H Khafagy M T Dawoud M T Attia. Volume 38 Issue 3 June 2015 pp 773-781 ...

  17. Intermolecular Interactions in Ternary Glycerol–Sample–H2O

    DEFF Research Database (Denmark)

    Westh, Peter; Rasmussen, Erik Lumby; Koga, Yoshikata

    2011-01-01

    We studied the intermolecular interactions in ternary glycerol (Gly)–sample (S)–H2O systems at 25 °C. By measuring the excess partial molar enthalpy of Gly, HGlyEHEGly, we evaluated the Gly–Gly enthalpic interaction, HGly-GlyEHEGly--Gly, in the presence of various samples (S). For S, tert...

  18. Excess isentropic compressibility and speed of sound of the ternary ...

    Indian Academy of Sciences (India)

    These excess properties of the binary mixtures were fitted to Redlich-Kister equation, while the Cibulka's equation was used to fit the values related to the values to the ternary system. These excess properties have been used to discuss the presence of significant interactions between the component molecules in the binary ...

  19. Robust self-triggered coordination with ternary controllers

    NARCIS (Netherlands)

    De Persis, Claudio; Frasca, Paolo

    2013-01-01

    This paper regards the coordination of networked systems, studied in the framework of hybrid dynamical systems. We design a coordination scheme which combines the use of ternary controllers with a self-triggered communication policy. The communication policy requires the agents to measure, at each

  20. Univolatility curves in ternary mixtures: geometry and numerical computation

    DEFF Research Database (Denmark)

    Shcherbakova, Nataliya; Rodriguez-Donis, Ivonne; Abildskov, Jens

    2017-01-01

    We propose a new non-iterative numerical algorithm allowing computation of all univolatility curves in homogeneous ternary mixtures independently of the presence of the azeotropes. The key point is the concept of generalized univolatility curves in the 3D state space, which allows the main...... computational part to be reduced to a simple integration of a system of ordinary differential equations....

  1. Evaluation of griseofulvin binary and ternary solid dispersions with HPMCAS.

    Science.gov (United States)

    Al-Obaidi, Hisham; Buckton, Graham

    2009-01-01

    The stability and dissolution properties of griseofulvin binary and ternary solid dispersions were evaluated. Solid dispersions of griseofulvin and hydroxypropyl methylcellulose acetate succinate (HPMCAS) were prepared using the spray drying method. A third polymer, poly[N-(2-hydroxypropyl)methacrylate] (PHPMA), was incorporated to investigate its effect on the interaction of griseofulvin with HPMCAS. In this case, HPMCAS can form H bonds with griseofulvin directly; the addition of PHPMA to the solid dispersion may enhance the stability of the amorphous griseofulvin due to greater interaction with griseofulvin. The X-ray powder diffraction results showed that griseofulvin (binary and ternary solid dispersions) remained amorphous for more than 19 months stored at 85% RH compared with the spray-dried griseofulvin which crystallized totally within 24 h at ambient conditions. The Fourier transform infrared scan showed that griseofulvin carbonyl group formed hydrogen bonds with the hydroxyl group in the HPMCAS, which could explain the extended stability of the drug. Further broadening in the peak could be seen when PHPMA was added to the solid dispersion, which indicates stronger interaction. The glass transition temperatures increased in the ternary solid dispersions regardless of HPMCAS grade. The dissolution rate of the drug in the solid dispersion (both binary and ternary) has significantly increased when compared with the dissolution profile of the spray-dried griseofulvin. These results reveal significant stability of the amorphous form due to the hydrogen bond formation with the polymer. The addition of the third polymer improved the stability but had a minor impact on dissolution.

  2. Excess isentropic compressibility and speed of sound of the ternary ...

    Indian Academy of Sciences (India)

    relation (NR), Van Deal's ideal mixing relation (IMR) and Junjie's relation (JR). The results are used to ... The compounds used were 2-propanol (>99 mass%), diethyl ether (>99.5 mass%) and n-hexane (>99 .... The excess speed of sound, uE, is estimated in binary and ternary mixtures using the following expression:.

  3. Viscometric and thermodynamic studies of interactions in ternary ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 117; Issue 3. Viscometric and thermodynamic studies of interactions in ternary solutions containing sucrose and aqueous alkali metal halides at 293.15, 303.15 and 313.15 K. Reena Gupta Mukhtar Singh. Volume 117 Issue 3 May 2005 pp 275-282 ...

  4. Modeling adsorption of binary and ternary mixtures on microporous media

    DEFF Research Database (Denmark)

    Monsalvo, Matias Alfonso; Shapiro, Alexander

    2007-01-01

    The goal of this work is to analyze the adsorption of binary and ternary mixtures on the basis of the multicomponent potential theory of adsorption (MPTA). In the MPTA, the adsorbate is considered as a segregated mixture in the external potential field emitted by the solid adsorbent. This makes i...

  5. A Simple Refraction Experiment for Probing Diffusion in Ternary Mixtures

    Science.gov (United States)

    Coutinho, Cecil A.; Mankidy, Bijith D.; Gupta, Vinay K.

    2010-01-01

    Diffusion is a fundamental phenomenon that is vital in many chemical processes such as mass transport in living cells, corrosion, and separations. We describe a simple undergraduate-level experiment based on Weiner's Method to probe diffusion in a ternary aqueous mixture of small molecular-weight molecules. As an illustration, the experiment…

  6. Electron paramagnetic resonance study of ternary Cu compounds ...

    Indian Academy of Sciences (India)

    Abstract. We report here electron paramagnetic resonance (EPR) measurements at 9 and 34 GHz, and room temperature (T ), in powder and single crystal samples of the ternary compounds of copper nitrate or copper chloride with glycine and 1,10-phenanthroline [Cu(Gly)(phen)(H2O)]·NO3·1.5H2O (1) and.

  7. IMPROVING THE PROPERTIES OF MILD STEEL BY TERNARY ...

    African Journals Online (AJOL)

    Protective coatings are perhaps the most extensively used system for chemical and mechanical degradation in application. ... mechanical and electrochemical resistance bond needful during application. .... binary phase of SiC and ZrO2 results to a reduction in the hardness value compare to the ternary phase which is in ...

  8. Experimental examination of ternary fission in nuclear track emulsion

    Science.gov (United States)

    Mamatkulov, K. Z.; Ambrožová, I.; Artemenkov, D. A.; Bradnova, V.; Firu, E.; Haiduc, M.; Kakona, M.; Kattabekov, R. R.; Marey, A.; Neagu, A.; Ploc, O.; Rusakova, V. V.; Stanoeva, R.; Turek, K.; Zaitsev, A. A.; Zarubin, P. I.; Zarubina, I. G.

    2017-11-01

    Activities performed in preparation for the search for ternary fission of heavy nuclei and the analysis of fragment angular correlations with nuclear track emulsion and an automated microscope are detailed. Surface irradiation of nuclear emulsion by a Cf source was initiated. Planar events containing nothing but fragment triples were found and studied.

  9. Tuning peptide amphiphile supramolecular structure for biomedical applications

    Science.gov (United States)

    Pashuck, Eugene Thomas, III

    The use of biomaterials in regenerative medicine has been an active area of research for more than a decade. Peptide amphiphiles, which are short peptide sequences coupled to alkyl tails, have been studied in the Stupp group since the beginning of the decade and been used for a variety of biomedical applications. Most of the work has focused on the bioactive epitopes places on the periphery of the PA molecules, but the interior amino acids, known as the beta-sheet region, give the PA nanofiber gel much of its mechanical strength. To study the important parameters in the beta-sheet region, six PA molecules were constructed to determine the influence of beta-sheet length and order of the amino acids in the beta-sheet. It was found that having beta-sheet forming amino acids near the center of the fiber improves PA gel stiffness, and that having extra amino acids that have preferences for other secondary structures, like alpha-helix decreased the gels stiffness. Using FTIR and circular dichroism it was found that the mechanical properties are influenced by the amount of twist in the beta-sheet, and PAs that have more twisted beta-sheets form weaker gels. The effect amino acid properties have on peptide amphiphile self-assembly where studied by synthesizining molecules with varying side group size and hydrophobicity. It was found that smaller amino acids lead to stiffer gels and when two amino acids had the same size the amino acid with the larger beta-sheet propensity lead to a stiffer gel. Furthermore, small changes in peptide structure were found to lead to big changes in nanostructure, as leucine and isoleucine, which have the same size but slightly different structures, form flat ribbons and cylindrical nanofibers, respectively. Phenylalanine and alanine were studied more indepth because they represent the effects of adding an aromatic group to amino acids in the beta-sheet regon. These phenylalanine PAs formed short, twisted ribbons when freshly dissolved in water

  10. Colloidosomes formed by nonpolar/polar/nonpolar nanoball amphiphiles

    Science.gov (United States)

    Chang, Hung-Yu; Tu, Sheng-Hung; Sheng, Yu-Jane; Tsao, Heng-Kwong

    2014-08-01

    Fullerene-based amphiphiles are able to form bilayer vesicles in aqueous solution. In this study, the self-assembly behavior of polymer-tethered nanoballs (NBs) with nonpolar/polar/nonpolar (n-p-n') motif in a selective solvent is investigated by dissipative particle dynamics. A model NB bears two hydrophobic polymeric arms (n'-part) tethered on an extremely hydrophobic NB (n-part) with hydrophilic patch (p-part) patterned on its surface. Dependent on the hydrophobicity and length of tethered arms, three types of aggregates are exhibited, including NB vesicle, core-shell micelle, and segmented-worm. NB vesicles are developed for a wide range of hydrophobic arm lengths. The presence of tethered arms perturbs the bilayer structure formed by NBs. The structural properties including the order parameter, membrane thickness, and area density of the inner leaflet decrease with increasing the arm length. These results indicate that for NBs with longer arms, the extent of interdigitation in the membrane rises so that the overcrowded arms in the inner corona are relaxed. The transport and mechanical properties are evaluated as well. As the arm length grows, the permeability increases significantly because the steric bulk of tethered arms loosens the packing of NBs. By contrast, the membrane tension decreases owing to the reduction of NB/solvent contacts by the polymer corona. Although fusion can reduce membrane tension, NB vesicles show strong resistance to fusion. Moreover, the size-dependent behavior observed in small liposomes is not significant for NB vesicles due to isotropic geometry of NB. Our simulation results are consistent with the experimental findings.

  11. Amphiphilic and phase-separable ionic liquids for biomass processing.

    Science.gov (United States)

    Holding, Ashley J; Heikkilä, Mikko; Kilpeläinen, Ilkka; King, Alistair W T

    2014-05-01

    One main limiting factor for the technoeconomics of future bioprocesses that use ionic liquids (ILs) is the recovery of the expensive and potentially toxic IL. We have demonstrated a new series of phase-separable ionic liquids, based on the hydrophobic tetraalkylphosphonium cation ([PRRRR](+)), that can dissolve lignin in the neat state but also hemicellulose and high-purity cellulose in the form of their electrolyte solutions with dipolar aprotic solvents. For example, the IL trioctylmethylphosphonium acetate ([P8881][OAc]) was demonstrated to dissolve up to 19 wt % of microcrystalline cellulose (MCC) at 60 °C with the addition of 40 wt % of DMSO. It was found that the MCC saturation point is dependent on the molar ratio of DMSO and IL in solution. At the optimum saturation, a ∼1:1 molar ratio of [P8881][OAc] to anhydroglucose units is observed, which demonstrates highly efficient solvation. This is attributed to the positive contribution that these more amphiphilic cation-anion pairs provide, in the context of the Lindman hypothesis. This effective dissolution is further illustrated by solution-state HSQC NMR spectroscopy on MCC. Finally, it is also demonstrated that these electrolytes are phase separable by the addition of aqueous solutions. The addition of 10 % NaOAc solution allows a near quantitative recovery of high-purity [P8881][OAc]. However, increased volumes of aqueous solution reduced the recovery. The regenerated material was found to partially convert into the cellulose II crystalline polymorph. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. A bioengineered peripheral nerve construct using aligned peptide amphiphile nanofibers.

    Science.gov (United States)

    Li, Andrew; Hokugo, Akishige; Yalom, Anisa; Berns, Eric J; Stephanopoulos, Nicholas; McClendon, Mark T; Segovia, Luis A; Spigelman, Igor; Stupp, Samuel I; Jarrahy, Reza

    2014-10-01

    Peripheral nerve injuries can result in lifelong disability. Primary coaptation is the treatment of choice when the gap between transected nerve ends is short. Long nerve gaps seen in more complex injuries often require autologous nerve grafts or nerve conduits implemented into the repair. Nerve grafts, however, cause morbidity and functional loss at donor sites, which are limited in number. Nerve conduits, in turn, lack an internal scaffold to support and guide axonal regeneration, resulting in decreased efficacy over longer nerve gap lengths. By comparison, peptide amphiphiles (PAs) are molecules that can self-assemble into nanofibers, which can be aligned to mimic the native architecture of peripheral nerve. As such, they represent a potential substrate for use in a bioengineered nerve graft substitute. To examine this, we cultured Schwann cells with bioactive PAs (RGDS-PA, IKVAV-PA) to determine their ability to attach to and proliferate within the biomaterial. Next, we devised a PA construct for use in a peripheral nerve critical sized defect model. Rat sciatic nerve defects were created and reconstructed with autologous nerve, PLGA conduits filled with various forms of aligned PAs, or left unrepaired. Motor and sensory recovery were determined and compared among groups. Our results demonstrate that Schwann cells are able to adhere to and proliferate in aligned PA gels, with greater efficacy in bioactive PAs compared to the backbone-PA alone. In vivo testing revealed recovery of motor and sensory function in animals treated with conduit/PA constructs comparable to animals treated with autologous nerve grafts. Functional recovery in conduit/PA and autologous graft groups was significantly faster than in animals treated with empty PLGA conduits. Histological examinations also demonstrated increased axonal and Schwann cell regeneration within the reconstructed nerve gap in animals treated with conduit/PA constructs. These results indicate that PA nanofibers may

  13. Soft/hard Coupled Amphiphilic Polymer Nanospheres for Water Lubrication.

    Science.gov (United States)

    Li, Zhaoxia; Ma, Shuanhong; Zhang, Ga; Wang, Daoai; Zhou, Feng

    2018-02-22

    Amphiphilic polymer nanospheres of poly (3-Sulfopropyl methacrylate potassium salt -co-styrene) [P(SPMA-co-St)] were prepared by a simple soap-free emulsion polymerization method and used as efficient water lubrication additive to enhance the anti-wear behaviors of Ti6Al4V alloy. The monodisperse and flexible P(SPMA-co-St) bi-component copolymer nanospheres were synthesized with a controllable manner by adjusting the mass fraction ratio of the monomers, with the hydrophobic polystyrene (PSt) as the hard and skeletal carrier component, and the hydrophilic PSPMA with hydration layer structure as the soft lubrication layer in the course of friction. The influences of the monomers concentration, the copolymer nanospheres additive content, the load and the frequency of the friction conditions on their tribological properties were studied in detail, and a probable anti-wear mechanism of the soft/hard coupled copolymer nanospheres under water lubrication was also proposed. The results show that compared with pure PSt the P(SPMA-co-St) polymer nanospheres exhibited better anti-wear property as additive for water lubrication, and the friction coefficient and the wear volume were first decrease and then increase with the increase of the SPMA content, indicating the hydrophilic SPMA has a significant effect on lubrication properties owing to its hydration performance. Furthermore, with the increase of polymer nanospheres concentration, the friction coefficient and wear amount also decreased to a stable and low value at the saturation concentration of 1 w%. The flexible polymer nanospheres with hydrophilic and soft SPMA shell and rigid PS core exhibited good friction-reduction and anti-wear performance as lubrication additive, indicating promising and potential applications in water lubrication and biological lubrication.

  14. Colloidosomes formed by nonpolar/polar/nonpolar nanoball amphiphiles

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Hung-Yu; Sheng, Yu-Jane, E-mail: yjsheng@ntu.edu.tw, E-mail: hktsao@cc.ncu.edu.tw [Department of Chemical Engineering, National Taiwan University, Taipei 106, Taiwan (China); Tu, Sheng-Hung [Department of Chemical and Materials Engineering, National Central University, Jhongli 320, Taiwan (China); Tsao, Heng-Kwong, E-mail: yjsheng@ntu.edu.tw, E-mail: hktsao@cc.ncu.edu.tw [Department of Chemical and Materials Engineering and Department of Physics, National Central University, Jhongli 320, Taiwan (China)

    2014-08-07

    Fullerene-based amphiphiles are able to form bilayer vesicles in aqueous solution. In this study, the self-assembly behavior of polymer-tethered nanoballs (NBs) with nonpolar/polar/nonpolar (n-p-n{sup ′}) motif in a selective solvent is investigated by dissipative particle dynamics. A model NB bears two hydrophobic polymeric arms (n{sup ′}-part) tethered on an extremely hydrophobic NB (n-part) with hydrophilic patch (p-part) patterned on its surface. Dependent on the hydrophobicity and length of tethered arms, three types of aggregates are exhibited, including NB vesicle, core-shell micelle, and segmented-worm. NB vesicles are developed for a wide range of hydrophobic arm lengths. The presence of tethered arms perturbs the bilayer structure formed by NBs. The structural properties including the order parameter, membrane thickness, and area density of the inner leaflet decrease with increasing the arm length. These results indicate that for NBs with longer arms, the extent of interdigitation in the membrane rises so that the overcrowded arms in the inner corona are relaxed. The transport and mechanical properties are evaluated as well. As the arm length grows, the permeability increases significantly because the steric bulk of tethered arms loosens the packing of NBs. By contrast, the membrane tension decreases owing to the reduction of NB/solvent contacts by the polymer corona. Although fusion can reduce membrane tension, NB vesicles show strong resistance to fusion. Moreover, the size-dependent behavior observed in small liposomes is not significant for NB vesicles due to isotropic geometry of NB. Our simulation results are consistent with the experimental findings.

  15. Preparation of ZnO nanoparticles in amphiphilic gel network

    Science.gov (United States)

    Sakohara, Shuji; Mori, Kazuya

    2008-02-01

    Nanosized zinc oxide (ZnO) particles were prepared in an amphiphilic N, N-dimethylacrylamide (DMAA) gel composed of a three-dimensional network with an effective pore size of the order of nanometers. The procedures consist of two major steps: (1) preparation of a precursor and (2) hydrolysis of the precursor to form nanoparticles. First, the plate-type dry gel was swollen in ethanol containing zinc acetate (ZnAc) in order to diffuse ZnAc molecules into the gel. Then, the ethanolic solution containing the gel was heated to ˜80°C to prepare the precursor. In the hydrolysis of the precursor, lithium hydroxide was added as the catalyst to the precursor solution containing the gel, and the solution was placed in an ultrasonic bath. Although the DMAA gel containing ZnO particles was completely transparent, it exhibited a yellow-green luminescence when irradiated with UV light. The ZnO nanoparticles stably dispersed in the gel network without growing, aggregating, or flowing out for over several months at a relatively high temperature of 50°C. The particle size depended on the effective pore size of the gel network, which could be controlled by the synthesis composition of the gel, that is, by the concentrations of DMAA as the primary monomer and N, N'-methylenebisacrylamide (MBAA) as the cross-linker used for synthesizing the gel. This implies that the particle size can be controlled at the nanosized level by the synthesis composition of the gel.

  16. Preparation of ZnO nanoparticles in amphiphilic gel network

    Energy Technology Data Exchange (ETDEWEB)

    Sakohara, Shuji, E-mail: sakohara@hiroshima-u.ac.jp; Mori, Kazuya [Hiroshima University, Department of Chemical Engineering, Graduate School of Engineering (Japan)

    2008-02-15

    Nanosized zinc oxide (ZnO) particles were prepared in an amphiphilic N,N-dimethylacrylamide (DMAA) gel composed of a three-dimensional network with an effective pore size of the order of nanometers. The procedures consist of two major steps: (1) preparation of a precursor and (2) hydrolysis of the precursor to form nanoparticles. First, the plate-type dry gel was swollen in ethanol containing zinc acetate (ZnAc) in order to diffuse ZnAc molecules into the gel. Then, the ethanolic solution containing the gel was heated to {approx}80 deg. C to prepare the precursor. In the hydrolysis of the precursor, lithium hydroxide was added as the catalyst to the precursor solution containing the gel, and the solution was placed in an ultrasonic bath. Although the DMAA gel containing ZnO particles was completely transparent, it exhibited a yellow-green luminescence when irradiated with UV light. The ZnO nanoparticles stably dispersed in the gel network without growing, aggregating, or flowing out for over several months at a relatively high temperature of 50 deg. C. The particle size depended on the effective pore size of the gel network, which could be controlled by the synthesis composition of the gel, that is, by the concentrations of DMAA as the primary monomer and N,N'-methylenebisacrylamide (MBAA) as the cross-linker used for synthesizing the gel. This implies that the particle size can be controlled at the nanosized level by the synthesis composition of the gel.

  17. Amphiphilic phase-transforming catalysts for transesterification of triglycerides

    Science.gov (United States)

    Nawaratna, Gayan Ivantha

    Heterogeneous catalytic reactions that involve immiscible liquid-phase reactants are challenging to conduct due to limitations associated with mass transport. Nevertheless, there are numerous reactions such as esterification, transesterification, etherification, and hydrolysis where two immiscible liquid reactants (such as polar and non-polar liquids) need to be brought into contact with a catalyst. With the intention of alleviating mass transport issues associated with such systems but affording the ability to separate the catalyst once the reaction is complete, the overall goal of this study is geared toward developing a catalyst that has emulsification properties as well as the ability to phase-transfer (from liquid-phase to solid-phase) while the reaction is ongoing and evaluating the effectiveness of such a catalytic process in a practical reaction. To elucidate this concept, the transesterification reaction was selected. Metal-alkoxides that possess acidic and basic properties (to catalyze the reaction), amphiphilic properties (to stabilize the alcohol/oil emulsion) and that can undergo condensation polymerization when heated (to separate as a solid subsequent to the completion of the reaction) were used to test the concept. Studies included elucidating the effect of metal sites and alkoxide sites and their concentration effects on transesterification reaction, effect of various metal alkoxide groups on the phase stability of the reactant system, and kinetic effects of the reaction system. The studies revealed that several transition-metal alkoxides, especially, titanium and yttrium based, responded positively to this reaction system. These alkoxides were able to be added to the reaction medium in liquid phase and were able to stabilize the alcohol/oil system. The alkoxides were selective to the transesterification reaction giving a range of ester yields (depending on the catalyst used). It was also observed that transition-metal alkoxides were able to be

  18. Electrostatically Driven Assembly of Charged Amphiphiles Forming Crystallized Membranes, Vesicles and Nanofiber Arrays

    Science.gov (United States)

    Leung, Cheuk Yui Curtis

    Charged amphiphilic molecules can self-assemble into a large variety of objects including membranes, vesicles and fibers. These micro to nano-scale structures have been drawing increasing attention due to their broad applications, especially in biotechnology and biomedicine. In this dissertation, three self-assembled systems were investigated: +3/-1 self-assembled catanionic membranes, +2/-1 self-assembled catanionic membranes and +1 self-assembled nanofibers. Transmission electron microscopy (TEM) combined with synchrotron small and wide angle x-ray scattering (SAXS and WAXS) were used to characterize the coassembled structures from the mesoscopic to nanometer scale. We designed a system of +3 and -1 ionic amphiphiles that coassemble into crystalline ionic bilayer vesicles with large variety of geometries that resemble polyhedral cellular crystalline shells and archaea wall envelopes. The degree of ionization of the amphiphiles and their intermolecular electrostatic interactions can be controlled by varying pH. The molecular packing of these membranes showed a hexagonal to rectangular-C to hexagonal phase transition with increasing pH, resulting in significant changes to the membrane morphology. A similar mixture of +2 and -1 ionic amphiphiles was also investigated. In addition to varying pH, which controls the headgroup attractions, we also adjust the tail length of the amphiphiles to control the van der Waals interactions between the tails. A 2D phase diagram was developed to show how pH and tail length can be used to control the intermolecular packing within the membranes. Another system of self-assembled nanofiber network formed by positively charged amphiphiles was also studied. These highly charged fibers repel each other and are packed in hexagonal lattice with lattice constant at least eight times of the fiber diameter. The d-spacing and the crystal structure can be controlled by varying the solution concentration and temperature.

  19. Magnetic amphiphilic hybrid carbon nanotubes containing N-doped and undoped sections: powerful tensioactive nanostructures

    Science.gov (United States)

    Purceno, Aluir D.; Machado, Bruno F.; Teixeira, Ana Paula C.; Medeiros, Tayline V.; Benyounes, Anas; Beausoleil, Julien; Menezes, Helvecio C.; Cardeal, Zenilda L.; Lago, Rochel M.; Serp, Philippe

    2014-11-01

    In this work, unique amphiphilic magnetic hybrid carbon nanotubes (CNTs) are synthesized and used as tensioactive nanostructures in different applications. These CNTs interact very well with aqueous media due to the hydrophilic N-doped section, whereas the undoped hydrophobic one has strong affinity for organic molecules. The amphiphilic character combined with the magnetic properties of these CNTs opens the door to completely new and exciting applications in adsorption science and catalysis. These amphiphilic N-doped CNTs can also be used as powerful tensioactive emulsification structures. They can emulsify water/organic mixtures and by a simple magnetic separation the emulsion can be easily broken. We demonstrate the application of these CNTs in the efficient adsorption of various molecules, in addition to promoting biphasic processes in three different reactions, i.e. transesterification of soybean oil, quinoline extractive oxidation with H2O2 and a metal-catalyzed aqueous oxidation of heptanol with molecular oxygen.In this work, unique amphiphilic magnetic hybrid carbon nanotubes (CNTs) are synthesized and used as tensioactive nanostructures in different applications. These CNTs interact very well with aqueous media due to the hydrophilic N-doped section, whereas the undoped hydrophobic one has strong affinity for organic molecules. The amphiphilic character combined with the magnetic properties of these CNTs opens the door to completely new and exciting applications in adsorption science and catalysis. These amphiphilic N-doped CNTs can also be used as powerful tensioactive emulsification structures. They can emulsify water/organic mixtures and by a simple magnetic separation the emulsion can be easily broken. We demonstrate the application of these CNTs in the efficient adsorption of various molecules, in addition to promoting biphasic processes in three different reactions, i.e. transesterification of soybean oil, quinoline extractive oxidation with H2O2 and

  20. Macroscopic alignment of graphene stacks by Langmuir-Blodgett deposition of amphiphilic hexabenzocoronenes

    DEFF Research Database (Denmark)

    Laursen, B.W.; Nørgaard, K.; Reitzel, N.

    2004-01-01

    e present structural studies of Langmuir V and Langmuir-Blodgett (LB) films of new amphiphilic hexa-peri-hexabenzocoronene (HBC) discotics, carrying five branched alkyl side chains and one polar group. The polar group is either a carboxylic acid moiety or an electron acceptor moiety (anthraquinone......). Grazing-incidence X-ray diffraction (GIXD) and X-ray reflectivity, both utilizing synchrotron radiation, show that these amphiphilic HBCs form well-defined Langmuir monolayers at the air-water interface, with pi-stacked columnar structure where the HBC cores are rotated around the surface normal...

  1. Interactions of the amphiphiles arbutin and tryptophan with phosphatidylcholine and phosphatidylethanolamine bilayers in the dry state

    Science.gov (United States)

    2013-01-01

    Background Water is essential for life, but some organisms can survive complete desiccation, while many more survive partial dehydration during drying or freezing. The function of some protective molecules, such as sugars, has been extensively studied, but much less is known about the effects of amphiphiles such as flavonoids and other aromatic compounds. Amphiphiles may be largely soluble under fully hydrated conditions, but will partition into membranes upon removal of water. Little is known about the effects of amphiphiles on membrane stability and how amphiphile structure and function are related. Here, we have used two of the most intensively studied amphiphiles, tryptophan (Trp) and arbutin (Arb), along with their isolated hydrophilic moieties glycine (Gly) and glucose (Glc) to better understand structure-function relationships in amphiphile-membrane interactions in the dry state. Results Fourier-transform infrared (FTIR) spectroscopy was used to measure gel-to-liquid crystalline phase transition temperatures (Tm) of liposomes formed from phosphatidylcholine and phosphatidylethanolamine in the presence of the different additives. In anhydrous samples, both Glc and Arb strongly depressed Tm, independent of lipid composition, while Gly had no measurable effect. Trp, on the other hand, either depressed or increased Tm, depending on lipid composition. We found no evidence for strong interactions of any of the compounds with the lipid carbonyl or choline groups, while all additives except Gly seemed to interact with the phosphate groups. In the case of Arb and Glc, this also had a strong effect on the sugar OH vibrations in the FTIR spectra. In addition, vibrations from the hydrophobic indole and phenol moieties of Trp and Arb, respectively, provided evidence for interactions with the lipid bilayers. Conclusions The two amphiphiles Arb and Trp interact differently with dry bilayers. The interactions of Arb are dominated by contributions of the Glc moiety, while

  2. Spacer structure and hydrophobicity influences transfection activity of novel polycationic gemini amphiphiles.

    Science.gov (United States)

    Puchkov, Pavel A; Kartashova, Irina A; Shmendel, Elena V; Luneva, Anastasya S; Morozova, Nina G; Zenkova, Marina A; Maslov, Mikhail A

    2017-08-01

    Three novel polycationic gemini amphiphiles with different spacers were developed and evaluated in terms of their physiochemical properties and transfection efficiencies. Cationic liposomes formed by these amphiphiles and the helper lipid DOPE were able to successfully condense DNA, as shown by gel mobility shift and ethidium bromide intercalation assays. Transfection activity of the liposomes was superior to Lipofectamine(®) 2000 and was dependent on spacer structure, hydrophobicity, and nucleic acid type (pDNA or siRNA). We demonstrated that the cationic liposomes 2X6/DOPE and 2X7/DOPE are potential non-toxic vehicles for gene delivery. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Copolymer SJ-1 as a Fluid Loss Additive for Drilling Fluid with High Content of Salt and Calcium

    Directory of Open Access Journals (Sweden)

    Hongping Quan

    2014-01-01

    Full Text Available A ternary copolymer of 2-acrylamide-2-methyl propane sulfonic acid (AMPS, acrylamide (AM, and allyl alcohol polyoxyethylene ether (APEG with a side chain polyoxyethylene ether (C2H4On SJ-1 were designed and synthesized in this work. Good temperature resistance and salt tolerance of “–SO3-” of AMPS, strong absorption ability of “amino-group” of AM, and good hydrability of side chain polyoxyethylene ether (C2H4On of APEG provide SJ-1 excellent properties as a fluid loss additive. The chemical structure of ternary copolymer was characterized by Fourier transform infrared (FTIR spectroscopy. The molecular weight and its distribution were determined by gel permeation chromatography (GPC. The API fluid loss of drilling fluid decreased gradually with the increasing concentration of NaCl and CaCl2 in the mud system. SJ-1 was applied well in the drilling fluid even at a high temperature of 220°C. Results of zeta potential of modified drilling fluid showed the dispersion stability of drilling fluid system. Scanning electron microscopy (SEM analysis showed the microstructure of the surface of the filter cake obtained from the drilling fluid modified by SJ-1.

  4. Pseudo-ternary phase diagrams of lecithin-based microemulsions: influence of monoalkylphosphates.

    Science.gov (United States)

    Trotta, M; Ugazio, E; Gasco, M R

    1995-06-01

    The formation of macroscopically homogeneous, stable, fluid, optically transparent, isotropic solutions (microemulsions) was delineated, at 25 degrees C, for systems containing water, soybean lecithin, sodium monoalkylphosphate (hexyl or ocytl), alcohol and isopropyl myristate. Six straight or branched alcohols (1-butanol, 2-butanol, isobutanol, 1-pentanol, 2-pentanol, 3-pentanol) were investigated as co-surfactants. A constant lecithin/alcohol mixing ratio was used, while the aqueous phase consisted of a solution of alkylphosphates at different concentrations. An increase of the microemulsion domain was seen by increasing the concentration of the alkylphosphate. With 0.2m hexylphosphate, as aqueous phase, the microemulsion domain consisted of a single, region, that, in the presence of butylic alcohols, spanded the greater portion of the phase diagram. In the presence of amyl alcohols the area of this region was much smaller. With 0.2 m octylphosphate the realm of existence of the microemulsions, except for 1-pentanol, consisted of two regions separated by a liquid-crystal region. With all the alcohols examined, the liquid-crystal phase solubilized a larger amount of oil in the presence of octylphosphate than in the presence of hexylphosphate. The stability ranges of microemulsions in systems containing soybean, lecithin, alcohol, water, and isopropyl myristate can be greatly increased by using a second hydrophobic amphiphile, such as hexylphosphate, to adjust the hydrophilic-lipophilic balance or the spontaneous peaking properties of lecithin-alcohol systems.

  5. The effect of amphiphilic polymers with a continuous amphiphilicity profile on the membrane properties in a bicontinuous microemulsions studied by neutron scattering

    Science.gov (United States)

    Klemmer, Helge F. M.; Frielinghaus, Henrich; Allgaier, Jürgen; Ohl, Michael; Holderer, Olaf

    2017-06-01

    Microemulsion systems consisting of oil, water and surfactant have been studied with neutron scattering techniques. The amount of surfactant needed to form a microemulsion can be dramatically reduced by the addition of small amounts of amphiphilic block copolymers (boosting effect). Here, we studied the influence of block copolymers with gradually changing amphiphilicity from hydrophilic to hydrophobic. Small angle neutron scattering (SANS), neutron spin echo spectroscopy (NSE) and phase diagram measurements in combination give access to the elastic properties of the membrane. The underlying NSE experiments for this interpretation rely on smallest changes of the relaxation curves (of ca. 1% steps) for still small changes of the bending rigidity (of ca. 10% steps). This high reliability of the experiments conducted at the SNS-NSE displays the accuracy of the instrument itself and the latest developments of the evaluation software, which were necessary to interpret such tiny changes of the bending rigidity reliably.

  6. Changes of refractive indices in ternary mixtures containing chlorobenzene + n-hexane + (n-heptane or n-octane at 298.15 K

    Directory of Open Access Journals (Sweden)

    M. IGLESIAS

    2004-06-01

    Full Text Available The refractive indices of ternary mixtures of chlorobenzene + n-hexane + (n-heptane or n-octane have been measured at 298.15 K and at atmospheric pressure over the whole composition diagram. Parameters of polynomial equations which represent the composition dependence of physical and derived properties are gathered. The experimental refractive indices and the ternary derived properties are compared with the data obtained using several predictive semi-empirical models. The use of the Soave–Redlich–Kwong (SRK and the Peng–Robinson (PR cubic equations of state with the Van der Waals one-fluid mixing rule, which incorporate different combining rules to predict refractive indices on mixing, are tested against the measured results, good agrement being obtained.

  7. Neurobioactive peptide amphiphile nanofiber scaffolds for spinal cord repair

    Science.gov (United States)

    Niece, Krista Lynne

    This thesis describes a set of peptide amphiphiles (PAs) designed for spinal cord repair (SCI). These PAs self: assemble under physiological conditions into nanofibers that cause macroscopic gelation. Hydrogen bonding, hydrophobicity, and electrostatics, which control the self-assembly, are compared throughout this thesis. PA performance is explored from a materials science and a bioengineering perspective. The salt-triggered gelation of three PAs with similar charge distributions, each bearing the neurite-outgrowth-promoting laminin-1 epitope IKVAV, is studied by rheology in Chapter 2. Stiffer, more hydrophilic PAs gel more slowly, as verified by testing analogous PAs bearing the fibronectin epitope RGD. Circular dichroism (CD) and turbidity suggest a nucleated self-assembly mechanism that depends on preexisting aggregates. Slowing gelation assists PA injection into the mouse spinal cord. Mouse neural progenitor cell (mNPC) studies with the IKVAV-PAs show cell survival, neurite outgrowth and selective neuronal differentiation, which may improve SCI repair by preventing glial scarring. Two PAs containing another laminin-1 epitope, YIGSR, are described in Chapter 3. In a negatively charged YIGSR-bearing PA (YIGSR-PA), mNPCs behave as in the IKVAV-bearing PAs, but grow longer neurites possibly due to epitope signaling. A positively charged YIGSR-bearing PA (Pos-YIGSR-PA) does not support mNPC survival. P19 cell line studies and zeta-potential measurements show that cell death is due to the PA substrate's surface charge and is specific to mNPCs. Mixed IKVAV-PA/YIGSR-PA scaffolds show averaging of cell behavior, while IKVAV-PA/Pos-YIGSR-PA mixtures fail to rescue cell viability. These dual-epitope scaffolds are studied in Chapter 4 by nuclear magnetic resonance (NMR) and CD. The like-charged mixture is composed of single-component fibers forming an interpenetrating network (IPN). The oppositely charged mixture is composed of mixed fibers, as predicted from simulation

  8. Polymerization and surface active properties of water-soluble amphiphilic polysiloxane copolymers modified with quaternary ammonium salts and long-carbon chain groups

    Energy Technology Data Exchange (ETDEWEB)

    Hou Aiqin [National Engineering Research Center for Dyeing and Finishing of Textiles, Donghua University, Shanghai 200051 (China)], E-mail: aiqinhou@dhu.edu.cn; Shi Yaqi [National Engineering Research Center for Dyeing and Finishing of Textiles, Donghua University, Shanghai 200051 (China)

    2009-07-15

    Two water-soluble amphiphilic polysiloxane copolymers modified with quaternary ammonium salts (QAS) and long-carbon chain groups are synthesized by copolymerization. FTIR, {sup 1}H NMR, and {sup 13}C NMR are used to characterize the structures of the amphiphilic polysiloxane copolymers. The results show that two water-soluble amphiphilic polysiloxanes have high surface activity in the aqueous solution and excellent wettability. They can form hydrophilic films on the surface of materials to improve the wettability of materials. The whiteness of the polyester fabrics treated with the amphiphilic polysiloxanes obviously reduces. The color yields (K/S) of the dyed fabrics treated with the amphiphilic polysiloxanes slightly increase. The amphiphilic polysiloxanes have shade darkening effect on dyed polyester microfiber fabric. However, the reflectance spectra curves of the fabrics treated without and with the amphiphilic polysiloxanes undergo no significant change.

  9. Stable Vesicles Composed of Mono- or Dicarboxylic Fatty Acids and Trimethylammonium Amphiphiles

    DEFF Research Database (Denmark)

    Caschera, Filippo; Bernardino de la Serna, Jorge; Löffler, Philipp M. G.

    2011-01-01

    of these amphiphiles mixtures at the air/water interface suggest that the stabilization of the structures can be attributed to two main interactions between headgroups, predominantly the formation of hydrogen bonds between protonated and deprotonated acids and then the additional electrostatic interactions between...

  10. Structure and Second Harmonic Generation of Langmuir-Blodgett Films of Two Chiral Amphiphilic Azo Dyes

    NARCIS (Netherlands)

    Schoondorp, Monique A.; Schouten, Arend Jan; Hulshof, Johannes; Feringa, Ben L.

    1993-01-01

    The properties and structure of Langmuir-Blodgett films of two new amphiphilic nonlinear optical dyes containing stereogenic (chiral) centers were studied. The dye molecule 4-[[4’-[(3R)-palmitoylpyrrolidin-1-yl]phenyl]azo]-3-nitrobenzoic acid (KZ16) forms homogeneous structures in the plane of the

  11. Recursive Alterations of the Relationship between Simple Membrane Geometry and Insertion of Amphiphilic Motifs

    DEFF Research Database (Denmark)

    Madsen, Kenneth Lindegaard; Herlo, Rasmus

    2017-01-01

    The shape and composition of a membrane directly regulate the localization, activity, and signaling properties of membrane associated proteins. Proteins that both sense and generate membrane curvature, e.g., through amphiphilic insertion motifs, potentially engage in recursive binding dynamics, w...

  12. Properties of amphiphilic oligonucleotide films at the air/water interface and after film transfer

    NARCIS (Netherlands)

    Keller, R.; Kwak, M.; de Vries, J. W.; Sawaryn, C.; Wang, J.; Anaya, M.; Muellen, K.; Butt, H. -J.; Herrmann, A.; Berger, R.; Müllen, K.

    2013-01-01

    The self-assembly of amphiphilic hybrid materials containing an oligonucleotide sequence at the air/water interface was investigated by means of pressure-molecular area (Pi-A) isotherms. In addition, films were transferred onto solid substrates and imaged using scanning force microscopy. We used

  13. The encapsulation of an amphiphile into polystyrene microspheres of narrow size distribution.

    Science.gov (United States)

    Pellach, Michal; Margel, Shlomo

    2011-12-06

    Encapsulation of compounds into nano- or microsized organic particles of narrow size distribution is of increasing importance in fields of advanced imaging and diagnostic techniques and drug delivery systems. The main technology currently used for encapsulation of molecules within uniform template particles while retaining their size distribution is based on particle swelling methodology, involving penetration of emulsion droplets into the particles. The swelling method, however, is efficient for encapsulation only of hydrophobic compounds within hydrophobic template particles. In order to be encapsulated, the molecules must favor the hydrophobic phase of an organic/aqueous biphasic system, which is not easily achieved for molecules of amphiphilic character.The following work overcomes this difficulty by presenting a new method for encapsulation of amphiphilic molecules within uniform hydrophobic particles. We use hydrogen bonding of acid and base, combined with a pseudo salting out effect, for the entrapment of the amphiphile in the organic phase of a biphasic system. Following the entrapment in the organic phase, we demonstrated, using fluorescein and (antibiotic) tetracycline as model molecules, that the swelling method usually used only for hydrophobes can be expanded and applied to amphiphilic molecules.

  14. The encapsulation of an amphiphile into polystyrene microspheres of narrow size distribution

    Directory of Open Access Journals (Sweden)

    Pellach Michal

    2011-12-01

    Full Text Available Abstract Encapsulation of compounds into nano- or microsized organic particles of narrow size distribution is of increasing importance in fields of advanced imaging and diagnostic techniques and drug delivery systems. The main technology currently used for encapsulation of molecules within uniform template particles while retaining their size distribution is based on particle swelling methodology, involving penetration of emulsion droplets into the particles. The swelling method, however, is efficient for encapsulation only of hydrophobic compounds within hydrophobic template particles. In order to be encapsulated, the molecules must favor the hydrophobic phase of an organic/aqueous biphasic system, which is not easily achieved for molecules of amphiphilic character. The following work overcomes this difficulty by presenting a new method for encapsulation of amphiphilic molecules within uniform hydrophobic particles. We use hydrogen bonding of acid and base, combined with a pseudo salting out effect, for the entrapment of the amphiphile in the organic phase of a biphasic system. Following the entrapment in the organic phase, we demonstrated, using fluorescein and (antibiotic tetracycline as model molecules, that the swelling method usually used only for hydrophobes can be expanded and applied to amphiphilic molecules.

  15. Investigating the Structure of Aggregates of an Amphiphilic Cyanine Dye with Molecular Dynamics Simulations

    NARCIS (Netherlands)

    Haverkort, Frank; Stradomska, Anna; de Vries, Alex H.; Knoester, Jasper

    2013-01-01

    We perform molecular dynamics (MD) simulations of the self-assembly process of pseudoisocyanine dye molecules with amphiphilic substituents (amphi-PIC). The spontaneous aggregation of cyanine molecules into large molecular J-aggregates with optical functionality has drawn attention for many decades

  16. Immunochemically identical hydrophilic and amphiphilic forms of the bovine adrenomedullary dopamine beta-hydroxylase

    DEFF Research Database (Denmark)

    Bjerrum, Ole Jannik; Helle, K B; Bock, Elisabeth Marianne

    1979-01-01

    By means of a monospecific antibody, dopamine beta-hydroxylase was monitored immunoelectrophoretically in various extracts of chromaffin granules. Approximately one-third of the dopamine beta-hydroxylase present was located in the membrane fraction and could only be liberated with detergent. The ...... with chymotrypsin and thermolysin the amphiphilic form could be convered into its hydrophilic counterpart....

  17. Transfection of small numbers of human endothelial cells by electroporation and synthetic amphiphiles

    NARCIS (Netherlands)

    van Leeuwen, E B; van der Veen, A Y; Hoekstra, D; Engberts, J B; Halie, M R; van der Meer, J; Ruiters, M H

    OBJECTIVES: This study compared the efficiency of electroporation and synthetic amphiphiles. (SAINT-2pp/DOPE) in transfecting small numbers of human endothelial cells. METHODS AND RESULTS: Optimal transfection conditions were tested and appeared to be 400 V and 960 microF for electroporation and a

  18. Conformational properties of rigid-chain amphiphilic macromolecules : The phase diagram

    NARCIS (Netherlands)

    Markov, V. A.; Vasilevskaya, V. V.; Khalatur, P. G.; ten Brinke, G.; Khokhlov, A. R.

    The coil-globule transition in rigid-chain amphiphilic macromolecules was studied by means of computer simulation, and the phase diagrams for such molecules in the solvent quality-persistence length coordinates were constructed. It was shown that the type of phase diagram depends to a substantial

  19. Aqueous Self-Assembly of Y-Shaped Amphiphilic Block Copolymers into Giant Vesicles.

    Science.gov (United States)

    Li, Hanping; Jin, Yong; Fan, Baozhu; Lai, Shuangquan; Sun, Xiaopeng; Qi, Rui

    2017-03-01

    The preparation and aqueous self-assembly of newly Y-shaped amphiphilic block polyurethane (PUG) copolymers are reported here. These amphiphilic copolymers, designed to have two hydrophilic poly(ethylene oxide) (PEO) tails and one hydrophobic alkyl tail via a two-step coupling reaction, can self-assemble into giant unilamellar vesicles (GUVs) (diameter ≥ 1000 nm) with a direct dissolution method in aqueous solution, depending on their Y-shaped structures and initial concentrations. More interesting, the copolymers can self-assemble into various distinct nano-/microstructures, such as spherical micelles, small vesicles, and GUVs, with the increase of their concentrations. The traditional preparation methods of GUVs generally need conventional amphiphilic molecules and additional complicated conditions, such as alternating electrical field, buffer solution, or organic solvent. Therefore, the self-assembly of Y-shaped PUGs with a direct dissolution method in aqueous solution demonstrated in this study supplies a new clue to fabricate GUVs based on the geometric design of amphiphilic polymers. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. A synthetic strategy for novel nonsymmetrical bola amphiphiles based on carbohydrates

    NARCIS (Netherlands)

    Schuur, B; Wagenaar, Anno; Heeres, Andre; Heeres, Erik H. J.

    2004-01-01

    A number of novel nonionic bolaform amphiphiles with nonidentical aldityl head groups, 1-(1-deoxy-D-galactitol-l-ylamino)-6-(1-deoxy-D- galactitol-1-ylamino)hexane (4a), 1-(1-deoxy-D-mannitol-1-ylamino)-6-(1-deoxy-D-glucitol-1-ylamino)hexane (4b). and

  1. Molecular design and synthesis of self-assembling camptothecin drug amphiphiles.

    Science.gov (United States)

    Cheetham, Andrew G; Lin, Yi-An; Lin, Ran; Cui, Honggang

    2017-06-01

    The conjugation of small molecular hydrophobic anticancer drugs onto a short peptide with overall hydrophilicity to create self-assembling drug amphiphiles offers a new prodrug strategy, producing well-defined, discrete nanostructures with a high and quantitative drug loading. Here we show the detailed synthesis procedure and how the molecular structure can influence the synthesis of the self-assembling prodrugs and the physicochemical properties of their assemblies. A series of camptothecin-based drug amphiphiles were synthesized via combined solid- and solution-phase synthetic techniques, and the physicochemical properties of their self-assembled nanostructures were probed using a number of imaging and spectroscopic techniques. We found that the number of incorporated drug molecules strongly influences the rate at which the drug amphiphiles are formed, exerting a steric hindrance toward any additional drugs to be conjugated and necessitating extended reaction time. The choice of peptide sequence was found to affect the solubility of the conjugates and, by extension, the critical aggregation concentration and contour length of the filamentous nanostructures formed. In the design of self-assembling drug amphiphiles, the number of conjugated drug molecules and the choice of peptide sequence have significant effects on the nanostructures formed. These observations may allow the fine-tuning of the physicochemical properties for specific drug delivery applications, ie systemic vs local delivery.

  2. Self-assembly of aromatic-derivatized amphiphiles: Phenyl, biphenyl, and terphenyl fatty acids and phospholipids

    Energy Technology Data Exchange (ETDEWEB)

    Geiger, H.C.; Perlstein, J.; Lachicotte, R.J.; Wyrozebski, K.; Whitten, D.G. [Univ. of Rochester, NY (United States)]|[Los Alamos National Lab., NM (United States). Chemical Science and Technology Div.

    1999-08-17

    This paper reports the synthesis of a series of amphiphiles (fatty acids and phosphatidylcholine derivatives) containing phenyl, biphenyl, and terphenyl chromophores inserted in the hydrocarbon chain and a study of their self-assembly in Langmuir-Blodgett films and aqueous dispersions. As observed and reported earlier for amphiphiles containing trans-stilbene, styrylthiophene, or azobenzene chromophores, several of the biphenyl and terphenyl derivatives show strong evidence of ground state association to form H aggregates characterized by a blue shift in absorption and a structured, red-shifted fluorescence. The phenyl amphiphiles show different behavior, suggesting that, even for pure films or bilayers, there is very little or no ground state association. For the biphenyl and terphenyl phospholipids, aqueous suspensions obtained by sonication are closed bilayer vesicles similar in size to those formed from the corresponding saturated phospholipids. The overall results of the present study indicate that biphenyl and terphenyl amphiphiles undergo aggregation processes to form compact arrays formally similar to those observed with stilbenen tolan, azobenzene, and squaraine derivatives but that the aromatic-aromatic interactions are considerably weaker than those for the more extended aromatics and lead to less distortion of the assembly structure.

  3. H-aggregation of azobenzene-substituted amphiphiles in vesicular membranes

    NARCIS (Netherlands)

    Kuiper, JM; Engberts, JBFN

    2004-01-01

    Photochemical switching has been studied of double-tailed phosphate amphiphiles containing azobenzene units in both tails in aqueous vesicular dispersions and in mixed vesicular systems with 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). Since the ease of switching depends on the strength of the

  4. Nucleation free energy of pore formation in an amphiphilic bilayer studied by molecular dynamics simulations.

    NARCIS (Netherlands)

    Tolpekina, T.V.; den Otter, Wouter K.; Briels, Willem J.

    2004-01-01

    The formation of a pore in a membrane requires a considerable rearrangement of the amphiphilic molecules about to form the bilayer edge surrounding the pore, and hence is accompanied by a steep increase of the free energy. Recent rupture and conductance experiments suggest that this reshuffling

  5. The influence of amphiphilic additional agents on the morphology and photoluminescence properties of calcium carbonate phosphor

    Science.gov (United States)

    Mou, Yongren; Kang, Ming; Liu, Min; Wang, Feng; Chen, Kexu; Sun, Rong

    2017-06-01

    In order to investigate the effect of amphiphilic additional agents on the morphology (particle shape, particle size and particle size distribution) and photoluminescence performance of calcium carbonate phosphor, the phosphors AA-CaCO3:Eu3+ (AA = glycerol or sodium dodecyl sulfate) were synthesized by the microwave-assisted co-precipitation method using glycerol (Gly) and sodium dodecyl sulfate (SDS) as amphiphilic additional agents (AA), respectively. The phase structure, morphology and luminescent properties of the as-synthesized samples were characterized by X-ray diffraction, scanning electron microscope, laser diffraction particle size analyzer and Fluorescence spectrophotometer, respectively. The results showed that the phase structure and morphology of AA-CaCO3:Eu3+ changed along with different types and amount of amphiphilic additional agents evidently. The particle size of Gly-CaCO3 decreased to 1.383 µm when the volume ratio reached 8:2 (Gly:H2O). Photoluminescence (PL) spectra show that all the AA-CaCO3:Eu3+ phosphors exhibit strong red emission peak originating from electric-dipole transition 5D0 → 7F2 (614 nm) of Eu3+ ions and the amphiphilic molecules (Gly and SDS) had a huge influence on photoluminescence intensity.

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

    DEFF Research Database (Denmark)

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

    1994-01-01

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

  7. Preparation of Vesicles and Nanoparticles of Amphiphilic Cyclodextrins Containing Labile Disulfide Bonds

    NARCIS (Netherlands)

    Nolan, Darren; Darcy, Raphael; Ravoo, B.J.

    2003-01-01

    Amphiphilic cyclodextrin derivatives were prepared in which a disulfide bond connects the hydrophobic substituents to the macrocycle. These compounds were obtained by 1,3-dicyclohexylcarbodiimide-mediated coupling reactions of heptakis(6-amino-6-deoxy)-B-cyclodextrins and disulfide-containing

  8. Amphiphile regulation of ion channel function by changes in the bilayer spring constant

    DEFF Research Database (Denmark)

    Lundbæk, Jens August; Koeppe, R.E.; Andersen, Oluf Sten

    2010-01-01

    be predicted from measurements of isolated changes in such properties. Thus, the bilayer contribution to the promiscuous regulation of membrane proteins by drugs and other amphiphiles remains unknown. To overcome this problem, we use gramicidin A (gA) channels as molecular force probes to measure the net...

  9. Programmed Self-Assembly of Branched Nanocrystals with an Amphiphilic Surface Pattern.

    Science.gov (United States)

    Taniguchi, Yuki; Sazali, Muhammad Adli Bin; Kobayashi, Yusei; Arai, Noriyoshi; Kawai, Tsuyoshi; Nakashima, Takuya

    2017-09-26

    Site-selective surface modification on the shape-controlled nanocrystals is a key approach in the programmed self-assembly of inorganic colloidal materials. This study demonstrates a simple methodology to gain self-assemblies of semiconductor nanocrystals with branched shapes through tip-to-tip attachment. Short-chained water-soluble cationic thiols are employed as a surface ligand for CdSe tetrapods and CdSe/CdS core/shell octapods. Because of the less affinity of arm-tip to the surface ligands compared to the arm-side wall, the tip-surface becomes uncapped to give a hydrophobic nature, affording an amphiphilic surface pattern. The amphiphilic tetrapods aggregated into porous agglomerates through tip-to-tip connection in water, while they afforded a hexagonally arranged Kagome-like two-dimensional (2D) assembly by the simple casting of aqueous dispersion with the aid of a convective self-assembly mechanism. A 2D net-like assembly was similarly obtained from amphiphilic octapods. A dissipative particle dynamics simulation using a planar tripod model with an amphiphilic surface pattern reproduced the formation of the Kagome-like assembly in a 2D confined space, demonstrating that the lateral diffusion of nanoparticles and the firm contacts between the hydrophobic tips play crucial roles in the self-assembly.

  10. Improved surface property of PVDF membrane with amphiphilic zwitterionic copolymer as membrane additive

    Science.gov (United States)

    Li, Jian-Hua; Li, Mi-Zi; Miao, Jing; Wang, Jia-Bin; Shao, Xi-Sheng; Zhang, Qi-Qing

    2012-06-01

    An attempt to improve hydrophilicity and anti-fouling properties of PVDF membranes, a novel amphiphilic zwitterionic copolymer poly(vinylidene fluoride)-graft-poly(sulfobetaine methacrylate) (PVDF-g-PSBMA) was firstly synthesized by atom transfer radical polymerization (ATRP) and used as amphiphilic copolymer additive in the preparation of PVDF membranes. The PVDF-g-PSBMA/PVDF blend membranes were prepared by immersion precipitation process. Fourier transform infrared attenuated reflection spectroscopy (FTIR-ATR) and X-ray photoelectronic spectroscopy (XPS) measurements confirmed that PSBMA brushes from amphiphilic additives were preferentially segregated to membrane-coagulant interface during membrane formation. The morphology of membranes was characterized by scanning electron microscopy (SEM). Water contact angle measurements showed that the surface hydrophilicity of PVDF membranes was improved significantly with the increasing of amphiphilic copolymer PVDF-g-PSBMA in cast solution. Protein static adsorption experiment and dynamic fouling resistance experiment revealed that the surface enrichment of PSBMA brush endowed PVDF blend membrane great improvement of surface anti-fouling ability.

  11. Thermodynamic calculations in ternary titanium–aluminium–manganese system

    Directory of Open Access Journals (Sweden)

    ANA I. KOSTOV

    2008-04-01

    Full Text Available Thermodynamic calculations in the ternary Ti–Al–Mn system are shown in this paper. The thermodynamic calculations were performed using the FactSage thermochemical software and database, with the aim of determining thermodynamic properties, such as activities, coefficient of activities, partial and integral values of the enthalpies and Gibbs energies of mixing and excess energies at two different temperatures: 2000 and 2100 K. Bearing in mind that no experimental data for the Ti–Al–Mn ternary system have been obtained or reported. The obtained results represent a good base for further thermodynamic analysis and may be useful as a comparison with some future critical experimental results and thermodynamic optimization of this system.

  12. Experimental Investigation of Ternary Alloys for Fusion Breeding Blankets

    Energy Technology Data Exchange (ETDEWEB)

    Choi, B. William [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chiu, Ing L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-10-26

    Future fusion power plants based on the deuterium-tritium (DT) fuel cycle will be required to breed the T fuel via neutron reactions with lithium, which will be incorporated in a breeding blanket that surrounds the fusion source. Recent work by LLNL proposed the used of liquid Li as the breeder in an inertial fusion energy (IFE) power plant. Subsequently, an LDRD was initiated to develop alternatives ternary alloy liquid metal breeders that have reduced chemical reactivity with water and air compared to pure Li. Part of the work plan was to experimentally investigate the phase diagrams of ternary alloys. Of particular interest was measurement of the melt temperature, which must be low enough to be compatible with the temperature limits of the steel used in the construction of the chamber and heat transfer system.

  13. A New Multifunctional Sensor for Measuring Concentrations of Ternary Solution

    Science.gov (United States)

    Wei, Guo; Shida, Katsunori

    This paper presents a multifunctional sensor with novel structure, which is capable of directly sensing temperature and two physical parameters of solutions, namely ultrasonic velocity and conductivity. By combined measurement of these three measurable parameters, the concentrations of various components in a ternary solution can be simultaneously determined. The structure and operation principle of the sensor are described, and a regression algorithm based on natural cubic spline interpolation and the least square method is adopted to estimate the concentrations. The performances of the proposed sensor are experimentally tested by the use of ternary aqueous solution of sodium chloride and sucrose, which is widely involved in food and beverage industries. This sensor could prove valuable as a process control sensor in industry fields.

  14. Cohesion energy calculations for ternary ionic novel crystals

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez P, G.; Cabrera, E. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, A.P. 20-364, 01000 Mexico D.F. (Mexico); Mijangos, R.R. [Centro de Investigacion en Fisica, Universidad de Sonora, A.P. 5-88, 83190 Hermosillo, Sonora (Mexico); Valdez, E. [Escuela Nacional de Estudios Profesionales Acatlan, Universidad Nacional Autonoma de Mexico, Santa Cruz Acatlan, Naucalpan (Mexico); Duarte, C. [Departamento de Geologia, Universidad de Sonora, 83000 Hermosillo, Sonora (Mexico)

    2001-07-01

    The present work calculates the value of the link energy of a crystalline ternary structure newly formed by alkali halides. The ternary structure prepared with different concentrations of KCl{sub x}KBrRbCl{sub 2} maintains a very good miscibility and stability. The calculation is based on the use of a generalization of the Vegard law (which generally is valid for binary compounds) for calculating the values of the lattice constant and the repulsive m exponent. The value of the lattice parameter given by X-ray diffractometry agrees with the close approximation of the calculated value of the method used. It also compares the value of energy cohesion obtained by the Born expression with more complex approximations. (Author)

  15. Fluid Dynamics

    DEFF Research Database (Denmark)

    Brorsen, Michael

    These lecture notes are intended mainly for the 7th semester course "Fluid Dynamics" offered by the Study Committee on Civil Engineering, Aalborg University.......These lecture notes are intended mainly for the 7th semester course "Fluid Dynamics" offered by the Study Committee on Civil Engineering, Aalborg University....

  16. Optical Properties of Silver Aluminium Sulphide Ternary Thin Films ...

    African Journals Online (AJOL)

    Ternary thin films of Silver Aluminium Sulphide (AgAlS2) have been prepared by chemical bath deposition techniques. Aqueous solution of 41.5 mls containing AgNO3, Al2(SO4)3, thiourea and EDTA was used, where AgNO3, Al2(SO4)3, thiourea were the source of Ag+, Al+ and S- respectively and EDTA was used as a ...

  17. Evaluation of Griseofulvin Binary and Ternary Solid Dispersions with HPMCAS

    OpenAIRE

    Al-Obaidi, Hisham; Buckton, Graham

    2009-01-01

    The stability and dissolution properties of griseofulvin binary and ternary solid dispersions were evaluated. Solid dispersions of griseofulvin and hydroxypropyl methylcellulose acetate succinate (HPMCAS) were prepared using the spray drying method. A third polymer, poly[N-(2-hydroxypropyl)methacrylate] (PHPMA), was incorporated to investigate its effect on the interaction of griseofulvin with HPMCAS. In this case, HPMCAS can form H bonds with griseofulvin directly; the addition of PHPMA to t...

  18. Some new quasi-twisted ternary linear codes

    Directory of Open Access Journals (Sweden)

    Rumen Daskalov

    2015-09-01

    Full Text Available Let [n, k, d]_q code be a linear code of length n, dimension k and minimum Hamming distance d over GF(q. One of the basic and most important problems in coding theory is to construct codes with best possible minimum distances. In this paper seven quasi-twisted ternary linear codes are constructed. These codes are new and improve the best known lower bounds on the minimum distance in [6].

  19. Theoretical prediction of topological insulator in ternary rare earth chalcogenides

    OpenAIRE

    Yan, Binghai; Zhang, Hai-Jun; Liu, Chao-Xing; Qi, Xiao-Liang; Frauenheim, Thomas; Zhang, Shou-Cheng

    2010-01-01

    A new class of three-dimensional topological insulator, ternary rare earth chalcogenides, is theoretically investigated with ab initio calculations. Based on both bulk band structure analysis and the direct calculation of topological surface states, we demonstrate that LaBiTe3 is a topological insulator. La can be substituted by other rare earth elements, which provide candidates for novel topological states such as quantum anomalous Hall insulator, axionic insulator and topological Kondo ins...

  20. Novel amphiphilic cationic porphyrin and its Ag(II) complex as potential anticancer agents.

    Science.gov (United States)

    Tovmasyan, Artak; Babayan, Nelli; Poghosyan, David; Margaryan, Kristine; Harutyunyan, Boris; Grigoryan, Rusanna; Sarkisyan, Natalia; Spasojevic, Ivan; Mamyan, Suren; Sahakyan, Lida; Aroutiounian, Rouben; Ghazaryan, Robert; Gasparyan, Gennadi

    2014-11-01

    In the present study we have synthesized a novel amphiphilic porphyrin and its Ag(II) complex through modification of water-soluble porphyrinic structure in order to increase its lipophilicity and in turn pharmacological potency. New cationic non-symmetrical meso-substituted porphyrins were characterized by UV-visible, electrospray ionization mass spectrometry (ESI-MS), (1)H NMR techniques, lipophilicity (thin-layer chromatographic retention factor, Rf), and elemental analysis. The key toxicological profile (i.e. cytotoxicity and cell line- (cancer type-) specificity; genotoxicity; cell cycle effects) of amphiphilic Ag porphyrin was studied in human normal and cancer cell lines of various tissue origins and compared with its water-soluble analog. Structural modification of the molecule from water-soluble to amphiphilic resulted in a certain increase in the cytotoxicity and a decrease in cell line-specificity. Importantly, Ag(II) porphyrin showed less toxicity to normal cells and greater toxicity to their cancerous counterparts as compared to cisplatin. The amphiphilic complex was also not genotoxic and demonstrated a slight cytostatic effect via the cell cycle delay due to the prolongation of S-phase. As expected, the performed structural modification affected also the photocytotoxic activity of metal-free amphiphilic porphyrin. The ligand tested on cancer cell line revealed a dramatic (more than 70-fold) amplification of its phototoxic activity as compared to its water-soluble tetracationic metal-free analog. The compound combines low dark cytotoxicity with 5 fold stronger phototoxicity relative to Chlorin e6 and could be considered as a potential photosensitizer for further development in photodynamic therapy. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Phase equilibria of the Mo-Al-Ho ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yitai; Chen, Xiaoxian; Liu, Hao [Guangxi Univ., Nanning (China). College of Materials Science and Engineering; Guangxi Univ., Nanning (China). Guangxi Key Laboratory of Processing for Non-ferrous Metal and Featured Materials; Zhan, Yongzhong [Guangxi Univ., Nanning (China). College of Materials Science and Engineering; Guangxi Univ., Nanning (China). Guangxi Key Laboratory of Processing for Non-ferrous Metal and Featured Materials; Guangxi Univ., Nanning (China). Center of Ecological Collaborative Innovation for Aluminum Industry

    2017-08-15

    Investigation into the reactions and phase equilibria of transition metal elements (i.e. Mo, Zr, Cr, V and Ti), Al and rare earths is academically and industrially important for the development of both refractory alloys and lightweight high-temperature materials. In this work, the equilibria of the Mo-Al-Ho ternary system at 773 K have been determined by using X-ray powder diffraction and scanning electron microscopy equipped with energy dispersive X-ray analysis. A new ternary phase Al{sub 4}Mo{sub 2}Ho has been found and the other ternary phase Al{sub 43}Mo{sub 4}Ho{sub 6} is observed. Ten binary phases in the Al-Mo and Al-Ho systems, including Al{sub 17}Mo{sub 4} rather than Al{sub 4}Mo, have been determined to exist at 773 K. The homogeneity ranges of AlMo{sub 3} and Al{sub 8}Mo{sub 3} phase are 7.5 at.% and 1 at.%, respectively. According to the phase-disappearing method, the maximum solubility of Al in Mo is about 16 at.%.

  2. Ternary Ag/epoxy adhesive with excellent overall performance.

    Science.gov (United States)

    Ji, Yan-Hong; Liu, Yu; Huang, Gui-Wen; Shen, Xiao-Jun; Xiao, Hong-Mei; Fu, Shao-Yun

    2015-04-22

    Excellent electrical conductivity (EC) generally conflicts with high lap shear strength (LSS) for electrically conductive adhesives (ECAs) since EC increases while LSS decreases with increasing conductive filler content. In this work, the ECAs with the excellent overall performance are developed based on the ternary hybrid of Ag microflakes (Ag-MFs), Ag nanospheres (Ag-NSs), and Ag nanowires (Ag-NWs). First, a low silver content adhesive system is determined. Then, the effects of the relative contents of Ag fillers on the EC and the LSS are studied. It is shown that a small amount of Ag-NSs or Ag-NWs can dramatically improve the EC for the Ag-MF/epoxy adhesives. The Ag-NSs and Ag-NWs with appropriate contents have a synergistic effect in improving the EC. Meanwhile, the LSS of the as-prepared adhesive with the appropriate Ag contents reaches an optimal value. Both the EC and the LSS of the as-prepared ternary hybrid ECA with a low content of 40 wt % Ag are higher than those of the commercial ECAs filled with the Ag-MF content over 60 wt %. Finally, the ternary hybrid ECA with the optimal formulation is shown to be promising for printing the radio frequency identification tag antennas as an immediate application example.

  3. Valence band electronic structure of Pd based ternary chalcogenide superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Lohani, H. [Institute of Physics, Sachivalaya Marg, Bhubaneswar 751005 (India); Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400085 (India); Mishra, P. [Institute of Physics, Sachivalaya Marg, Bhubaneswar 751005 (India); Goyal, R.; Awana, V.P.S. [National Physical Laboratory(CSIR), Dr. K. S. Krishnan Road, New Delhi 110012 (India); Sekhar, B.R., E-mail: sekhar@iopb.res.in [Institute of Physics, Sachivalaya Marg, Bhubaneswar 751005 (India); Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400085 (India)

    2016-12-15

    Highlights: • VB Photoemission study and DFT calculations on Pd based ternary superconductors are presented. • Nb{sub 2}Pd{sub 0.95}S{sub 5} shows a temperature dependent pseudogap. • VB spectral features of ternary superconductors are correlated to their structural geometry. - Abstract: We present a comparative study of the valence band electronic structure of Pd based ternary chalcogenide superconductors Nb{sub 2}Pd{sub 0.95}S{sub 5}, Ta{sub 2}Pd{sub 0.97}S{sub 6} and Ta{sub 2}Pd{sub 0.97}Te{sub 6} using experimental photoemission spectroscopy and density functional based theoretical calculations. We observe a qualitatively similarity between valence band (VB) spectra of Nb{sub 2}Pd{sub 0.95}S{sub 5} and Ta{sub 2}Pd{sub 0.97}S{sub 6}. Further, we find a pseudogap feature in Nb{sub 2}Pd{sub 0.95}S{sub 5} at low temperature, unlike other two compounds. We have correlated the structural geometry with the differences in VB spectra of these compounds. The different atomic packing in these compounds could vary the strength of inter-orbital hybridization among various atoms which leads to difference in their electronic structure as clearly observed in our DOS calculations.

  4. Realizing Ternary Logic in FPGAs for SWL DSP Systems

    Directory of Open Access Journals (Sweden)

    Tayeb Din

    2013-07-01

    Full Text Available Recently SWL (Short Word Length DSP (Digital Signal Processing applications has been proposed to overcome multiplier complexity that is evident in most of the digital applications. These SWL applications have been processed through sigma-delta modulation as a key element. For such applications, adder design plays vital role and can impact upon the chip area and its performance. In this paper, a ternary approach for adder tree has been proposed instead of binary that can accommodate more data with less chip-area at the cost of extra pin. The proposed ternary adder tree has been designed and developed in Quartus-II using three different design strategies namely T-gate (Ternary gate, LUT (Look Up Table and algebraic equations. Through rigorous simulation it was found that T-gate technique results in superior performance, an average of 23.5 and 33% improvement compared to the same adder structure based on Boolean Algebraic Equation and LUT, respectively. The proposed adder design would benefit the efficient implementation of SWL applications.

  5. Mutual Solubility of MEG, Water and Reservoir Fluid: Experimental Measurements and Modeling using the CPA Equation of State

    DEFF Research Database (Denmark)

    Riaz, Muhammad; Kontogeorgis, Georgios; Stenby, Erling Halfdan

    2011-01-01

    This work presents new experimental phase equilibrium data of binary MEG-reservoir fluid and ternary MEG-water-reservoir fluid systems at temperatures 275-326 K and at atmospheric pressure. The reservoir fluid consists of a natural gas condensate from a Statoil operated gas field in the North Sea...... fluid and polar compounds such as water and MEG. Satisfactory results are obtained for mutual solubility of MEG and gas condensate whereas some deviations are observed for the ternary system of MEG-water-gas condensate........ Prediction of mutual solubility of water, MEG and hydrocarbon fluids is important for the oil industry to ensure production and processing as well as to satisfy environmental regulations. The CPA equation of state has been successfully applied in the past to well defined systems containing associating...

  6. Information on individual interfaces in ternary polymer blends from positron annihilation lifetime studies

    Science.gov (United States)

    Meghala, D.; Ramya, P.; Pasang, T.; Ravikumar, H. B.; Ranganathaiah, C.

    2012-06-01

    Positron Annihilation Lifetime Spectroscopy has been used to determine the free volume content in the ternary blends of SAN/EVA/PVC. The method of deriving hydrodynamic interaction parameter (α) in binary polymer blends was modified for ternary polymer blend system characterized by three distinct interfaces. Each interface characterized, is associated with an α and its assertion for the ternary blend are compared with available literature data.

  7. Fluid dynamics of dilatant fluid

    DEFF Research Database (Denmark)

    Nakanishi, Hiizu; Nagahiro, Shin-ichiro; Mitarai, Namiko

    2012-01-01

    A dense mixture of granules and liquid often shows a severe shear thickening and is called a dilatant fluid. We construct a fluid dynamics model for the dilatant fluid by introducing a phenomenological state variable for a local state of dispersed particles. With simple assumptions for an equation...... of the state variable, we demonstrate that the model can describe basic features of the dilatant fluid such as the stress-shear rate curve that represents discontinuous severe shear thickening, hysteresis upon changing shear rate, and instantaneous hardening upon external impact. An analysis of the model...... reveals that the shear thickening fluid shows an instability in a shear flow for some regime and exhibits the shear thickening oscillation (i.e., the oscillatory shear flow alternating between the thickened and the relaxed states). The results of numerical simulations are presented for one- and two...

  8. Liquid-liquid equilibria for binary and ternary polymer solutions with PC-SAFT

    DEFF Research Database (Denmark)

    Lindvig, Thomas; Michelsen, Michael Locht; Kontogeorgis, Georgios

    2004-01-01

    are used for investigating the correlative and predictive capabilities of the thermodynamic model PC-SAFT. The investigation shows that the model correlates well experimental LLE data for binary as well as ternary systems but further predicts the behavior of the ternary systems with reasonably good......Two algorithms for evaluating liquid-liquid equilibria (LLE) for binary and ternary polymer solutions are presented. The binary algorithm provides the temperature versus concentration cloud-point curve at fixed pressure, whereas the ternary algorithm provides component 1 versus component 2...

  9. PREDICTION OF THERMODYNAMIC PROPERTIES OF COMPLEX FLUIDS

    Energy Technology Data Exchange (ETDEWEB)

    Marc Donohue

    2006-01-05

    ABSTRACT The goal of this research has been to generalize Density Functional Theory (DFT) for complex molecules, i.e. molecules whose size, shape, and interaction energies cause them to show significant deviations from mean-field behavior. We considered free energy functionals and minimized them for systems with different geometries and dimensionalities including confined fluids (such as molecular layers on surfaces and molecules in nano-scale pores), systems with directional interactions and order-disorder transitions, amphiphilic dimers, block copolymers, and self-assembled nano-structures. The results of this procedure include equations of equilibrium for these systems and the development of computational tools for predicting phase transitions and self-assembly in complex fluids. DFT was developed for confined fluids. A new phenomenon, surface compression of confined fluids, was predicted theoretically and confirmed by existing experimental data and by simulations. The strong attraction to a surface causes adsorbate molecules to attain much higher densities than that of a normal liquid. Under these conditions, adsorbate molecules are so compressed that they repel each other. This phenomenon is discussed in terms of experimental data, results of Monte Carlo simulations, and theoretical models. Lattice version of DFT was developed for modeling phase transitions in adsorbed phase including wetting, capillary condensation, and ordering. Phase behavior of amphiphilic dimers on surfaces and in solutions was modeled using lattice DFT and Monte Carlo simulations. This study resulted in predictive models for adsorption isotherms and for local density distributions in solutions. We have observed a wide variety of phase behavior for amphiphilic dimers, including formation of lamellae and micelles. Block copolymers were modeled in terms of configurational probabilities and in the approximation of random mixing entropy. Probabilities of different orientations for the

  10. pi-pi interaction of aromatic groups in amphiphilic molecules directing for single-crystalline mesostructured zeolite nanosheets

    National Research Council Canada - National Science Library

    Xu, Dongdong; Ma, Yanhang; Jing, Zhifeng; Han, Lu; Singh, Bhupendra; Feng, Ji; Shen, Xuefeng; Cao, Fenglei; Oleynikov, Peter; Sun, Huai; Terasaki, Osamu; Che, Shunai

    2014-01-01

    .... Here we report a concept for designing a single quaternary ammonium head amphiphilic template with strong ordered self-assembling ability through pi-pi stacking in hydrophobic side, which stabilizes...

  11. Adsorption of phthalic acid esters (PAEs) by amphiphilic polypropylene nonwoven from aqueous solution: the study of hydrophilic and hydrophobic microdomain.

    Science.gov (United States)

    Zhou, Xiangyu; Wei, Junfu; Zhang, Huan; Liu, Kai; Wang, Han

    2014-05-30

    A kind of amphiphilic polypropylene nonwoven with hydrophilic and hydrophobic microdomain was prepared through electron beam induced graft polymerization and subsequent ring opening reaction and then utilized in the adsorption of phthalic acid esters (PAEs). To elucidate the superiority of such amphiphilic microdomain, a unique structure without hydrophilic part was constructed as comparison. In addition, the adsorption behaviors including adsorption kinetics, isotherms and pH effect were systematically investigated. The result indicated that the amphiphilic structure and the synergy between hydrophilic and hydrophobic microdomain could considerably improve the adsorption capacities, rate and affinity. Particularly the existence of hydrophilic microdomain could reduce the diffusion resistance and energy barrier in the adsorption process. These adsorption results showed that the amphiphilic PP nonwoven have the potential to be used in environmental application. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Microspheres for protein delivery prepared from amphiphilic multiblock copolymers. 1. influence of preparation techniques on particle characteristics and protein delivery

    NARCIS (Netherlands)

    Bezemer, J.M.; Radersma, R.; Grijpma, Dirk W.; Dijkstra, Pieter J.; van Blitterswijk, Clemens; Feijen, Jan

    2000-01-01

    The entrapment of lysozyme in amphiphilic multiblock copolymer microspheres by emulsification and subsequent solvent removal processes was studied. The copolymers are composed of hydrophilic poly(ethylene glycol) (PEG) blocks and hydrophobic poly(butylene terephthalate) (PBT) blocks. Direct solvent

  13. Fluid dynamics

    CERN Document Server

    Bernard, Peter S

    2015-01-01

    This book presents a focused, readable account of the principal physical and mathematical ideas at the heart of fluid dynamics. Graduate students in engineering, applied math, and physics who are taking their first graduate course in fluids will find this book invaluable in providing the background in physics and mathematics necessary to pursue advanced study. The book includes a detailed derivation of the Navier-Stokes and energy equations, followed by many examples of their use in studying the dynamics of fluid flows. Modern tensor analysis is used to simplify the mathematical derivations, thus allowing a clearer view of the physics. Peter Bernard also covers the motivation behind many fundamental concepts such as Bernoulli's equation and the stream function. Many exercises are designed with a view toward using MATLAB or its equivalent to simplify and extend the analysis of fluid motion including developing flow simulations based on techniques described in the book.

  14. Isentropic expansion and related thermodynamic properties of non-ionic amphiphile-water mixtures.

    Science.gov (United States)

    Reis, João Carlos R; Douhéret, Gérard; Davis, Michael I; Fjellanger, Inger Johanne; Høiland, Harald

    2008-01-28

    A concise thermodynamic formalism is developed for the molar isentropic thermal expansion, ES,m = ( partial differential Vm/ partial differential T)(Sm,x), and the ideal and excess quantities for the molar, apparent molar and partial molar isentropic expansions of binary liquid mixtures. Ultrasound speeds were determined by means of the pulse-echo-overlap method in aqueous mixtures of 2-methylpropan-2-ol at 298.15 K over the entire composition range. These data complement selected extensive literature data on density, isobaric heat capacity and ultrasound speed for 9 amphiphile (methanol, ethanol, propan-1-ol, propan-2-ol, 2-methylpropan-2-ol, ethane-1,2-diol, 2-methoxyethanol, 2-ethoxyethanol or 2-butoxyethanol)-water binary systems, which form the basis of tables listing molar and excess molar isobaric expansions and heat capacities, and molar and excess molar isentropic compressions and expansions at 298.15 K and at 65 fixed mole fractions spanning the entire composition range and fine-grained in the water-rich region. The dependence on composition of these 9 systems is graphically depicted for the excess molar isobaric and isentropic expansions and for the excess partial molar isobaric and isentropic expansions of the amphiphile. The analysis shows that isentropic thermal expansion properties give a much stronger response to amphiphile-water molecular interactions than do their isobaric counterparts. Depending on the pair property-system, the maximum excess molar isentropic value is generally twenty- to a hundred-fold greater than the corresponding maximum isobaric value, and occurs at a lower mole fraction of the amphiphile. Values at infinite dilution of the 9 amphiphiles in water are given for the excess partial molar isobaric heat capacity, isentropic compression, isobaric expansion and isentropic expansion. These values are interpreted in terms of the changes occurring when amphiphile molecules cluster into an oligomeric form. Present results are discussed

  15. Administration of the optimized β-Lapachone-poloxamer-cyclodextrin ternary system induces apoptosis, DNA damage and reduces tumor growth in a human breast adenocarcinoma xenograft mouse model.

    Science.gov (United States)

    Seoane, Samuel; Díaz-Rodríguez, Patricia; Sendon-Lago, Juan; Gallego, Rosalia; Pérez-Fernández, Román; Landin, Mariana

    2013-08-01

    β-Lapachone (β-Lap) is a 1,2-orthonaphthoquinone that selectively induces cell death in human cancer cells through NAD(P)H:quinone oxidoreductase-1 (NQO1). NQO1 is overexpressed in a variety of tumors, as compared to normal adjacent tissue. However, the low solubility and non-specific distribution of β-Lap limit its suitability for clinical assays. We formulated β-Lap in an optimal random methylated-β-cyclodextrin/poloxamer 407 mixture (i.e., β-Lap ternary system) and, using human breast adenocarcinoma MCF-7 cells and immunodeficient mice, performed in vitro and in vivo evaluation of its anti-tumor effects on proliferation, cell cycle, apoptosis, DNA damage, and tumor growth. This ternary system is fluid at room temperature, gels over 29 °C, and provides a significant amount of drug, thus facilitating intratumoral delivery, in situ gelation, and the formation of a depot for time-release. Administration of β-Lap ternary system to MCF-7 cells induces an increase in apoptosis and DNA damage, while producing no changes in cell cycle. Moreover, in a mouse xenograft tumor model, intratumoral injection of the system significantly reduces tumor volume, while increasing apoptosis and DNA damage without visible toxicity to liver or kidney. These anti-tumoral effects and lack of visible toxicity make this system a promising new therapeutic agent for breast cancer treatment. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. The Lattice Compatibility Theory: Arguments for Recorded I-III-O2 Ternary Oxide Ceramics Instability at Low Temperatures beside Ternary Telluride and Sulphide Ceramics

    Directory of Open Access Journals (Sweden)

    K. Boubaker

    2013-01-01

    Full Text Available Some recorded behaviours differences between chalcopyrite ternary oxide ceramics and telluride and sulphides are investigated in the framework of the recently proposed Lattice Compatibility Theory (LCT. Alterations have been evaluated in terms of Urbach tailing and atomic valence shell electrons orbital eigenvalues, which were calculated through several approximations. The aim of the study was mainly an attempt to explain the intriguing problem of difficulties of elaborating chalcopyrite ternary oxide ceramics (I-III-O2 at relatively low temperatures under conditions which allowed crystallization of ternary telluride and sulphides.

  17. Novel amphiphilic poly(dimethylsiloxane) based polyurethane networks tethered with carboxybetaine and their combined antibacterial and anti-adhesive property

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Jingxian; Fu, Yuchen; Zhang, Qinghua, E-mail: qhzhang@zju.edu.cn; Zhan, Xiaoli; Chen, Fengqiu

    2017-08-01

    Highlights: • An amphiphilic poly(dimethylsiloxane) (PDMS) based polyurethane (PU) network tethered with carboxybetaine is prepared. • The surface distribution of PDMS and zwitterionic segments produces an obvious amphiphilic heterogeneous surface. • This designed PDMS-based amphiphilic PU network exhibits combined antibacterial and anti-adhesive properties. - Abstract: The traditional nonfouling materials are powerless against bacterial cells attachment, while the hydrophobic bactericidal surfaces always suffer from nonspecific protein adsorption and dead bacterial cells accumulation. Here, amphiphilic polyurethane (PU) networks modified with poly(dimethylsiloxane) (PDMS) and cationic carboxybetaine diol through simple crosslinking reaction were developed, which had an antibacterial efficiency of 97.7%. Thereafter, the hydrolysis of carboxybetaine ester into zwitterionic groups brought about anti-adhesive properties against bacteria and proteins. The surface chemical composition and wettability performance of the PU network surfaces were investigated by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and contact angle analysis. The surface distribution of PDMS and zwitterionic segments produced an obvious amphiphilic heterogeneous surface, which was demonstrated by atomic force microscopy (AFM). Enzyme-linked immunosorbent assays (ELISA) were used to test the nonspecific protein adsorption behaviors. With the advantages of the transition from excellent bactericidal performance to anti-adhesion and the combination of fouling resistance and fouling release property, the designed PDMS-based amphiphilic PU network shows great application potential in biomedical devices and marine facilities.

  18. Enhancing the protein resistance of silicone via surface-restructuring PEO-silane amphiphiles with variable PEO length.

    Science.gov (United States)

    Rufin, M A; Gruetzner, J A; Hurley, M J; Hawkins, M L; Raymond, E S; Raymond, J E; Grunlan, M A

    2015-04-14

    Silicones with superior protein resistance were produced by bulk-modification with poly(ethylene oxide) (PEO)-silane amphiphiles that demonstrated a higher capacity to restructure to the surface-water interface versus conventional non-amphiphilic PEO-silanes. The PEO-silane amphiphiles were prepared with a single siloxane tether length but variable PEO segment lengths: α-(EtO)3Si(CH2)2-oligodimethylsiloxane13-block-poly(ethylene oxide) n -OCH3 (n = 3, 8, and 16). Conventional PEO-silane analogues (n = 3, 8 and 16) as well as a siloxane tether-silane (i.e. no PEO segment) were prepared as controls. When surface-grafted onto silicon wafer, PEO-silane amphiphiles produced surfaces that were more hydrophobic and thus more adherent towards fibrinogen versus the corresponding PEO-silane. However, when blended into a silicone, PEO-silane amphiphiles exhibited rapid restructuring to the surface-water interface and excellent protein resistance whereas the PEO-silanes did not. Silicones modified with PEO-silane amphiphiles of PEO segment lengths n = 8 and 16 achieved the highest protein resistance.

  19. Adsorption of phthalic acid esters (PAEs) by amphiphilic polypropylene nonwoven from aqueous solution: The study of hydrophilic and hydrophobic microdomain

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Xiangyu [State Key Laboratory of Hollow Fiber Membrane Materials and Processes, Tianjin Polytechnic University, Tianjin 300387 (China); School of Environmental and Chemical Engineering, Tianjin Polytechnic University, Tianjin 300387 (China); Wei, Junfu, E-mail: weijunfu1963@163.com [State Key Laboratory of Hollow Fiber Membrane Materials and Processes, Tianjin Polytechnic University, Tianjin 300387 (China); School of Environmental and Chemical Engineering, Tianjin Polytechnic University, Tianjin 300387 (China); Zhang, Huan; Liu, Kai; Wang, Han [State Key Laboratory of Hollow Fiber Membrane Materials and Processes, Tianjin Polytechnic University, Tianjin 300387 (China); School of Environmental and Chemical Engineering, Tianjin Polytechnic University, Tianjin 300387 (China)

    2014-05-01

    Highlights: • Amphiphilic PP-g-GMA-OA nonwoven was prepared and characterized. • Synergy between hydrophilic and hydrophobic microdomain was elucidated. • The effects of hydrophilic microdomain on diffusion resistance and energy barrier were elucidated. • Adsorbent material with amphiphilic structures showed faster adsorption rate and lager adsorption capacity. - Abstract: A kind of amphiphilic polypropylene nonwoven with hydrophilic and hydrophobic microdomain was prepared through electron beam induced graft polymerization and subsequent ring opening reaction and then utilized in the adsorption of phthalic acid esters (PAEs). To elucidate the superiority of such amphiphilic microdomain, a unique structure without hydrophilic part was constructed as comparison. In addition, the adsorption behaviors including adsorption kinetics, isotherms and pH effect were systematically investigated. The result indicated that the amphiphilic structure and the synergy between hydrophilic and hydrophobic microdomain could considerably improve the adsorption capacities, rate and affinity. Particularly the existence of hydrophilic microdomain could reduce the diffusion resistance and energy barrier in the adsorption process. These adsorption results showed that the amphiphilic PP nonwoven have the potential to be used in environmental application.

  20. Prediction of thermophysical and transport properties of ternary organic non-electrolyte systems including water by polynomials

    Directory of Open Access Journals (Sweden)

    Đorđević Bojan D.

    2013-01-01

    Full Text Available The description and prediction of the thermophysical and transport properties of ternary organic non-electrolyte systems including water by the polynomial equations are reviewed. Empirical equations of Radojković et al. (also known as Redlich-Kister, Kohler, Jacob-Fitzner, Colinet, Tsao-Smith, Toop, Scatchard et al. and Rastogi et al. are compared with experimental data of available papers appeared in well know international journals (Fluid Phase Equilibria, Journal of Chemical and Engineering Data, Journal of Chemical Thermodynamics, Journal of Solution Chemistry, Journal of the Serbian Chemical Society, The Canadian Journal of Chemical Engineering, Journal of Molecular Liquids, Thermochimica Acta, etc.. The applicability of empirical models to estimate excess molar volumes, VE, excess viscosities, ηE, excess free energies of activation of a viscous flow,

  1. Removal of volatile organic compounds using amphiphilic cyclodextrin-coated polypropylene.

    Science.gov (United States)

    Lumholdt, Ludmilla; Fourmentin, Sophie; Nielsen, Thorbjørn T; Larsen, Kim L

    2014-01-01

    Polypropylene nonwovens were functionalised using a self-assembled, amphiphilic cyclodextrin coating and the potential for water purification by removal of pollutants was studied. As benzene is one of the problematic compounds in the Water Framework Directive, six volatile organic compounds (benzene and five benzene-based substances) were chosen as model compounds. The compounds were tested as a mixture in order to provide a more realistic situation since the wastewater will be a complex mixture containing multiple pollutants. The volatile organic compounds are known to form stable inclusion complexes with cyclodextrins. Six different amphiphilic cyclodextrin derivatives were synthesised in order to elucidate whether or not the uptake abilities of the coating depend on the structure of the derivative. Headspace gas chromatography was used for quantification of the uptake exploiting the volatile nature of benzene and its derivatives. The capacity was shown to increase beyond the expected stoichiometries of guest-host complexes with ratios of up to 16:1.

  2. Synthesis of an amphiphilic dendrimer-like block copolymer and its application on drug delivery

    KAUST Repository

    Wang, Shuaipeng

    2014-10-27

    Dendrimer-like amphiphilic copolymer is a kind of three-dimensional spherical structure polymer. An amphiphilic dendrimer-like diblock copolymer, PEEGE-G2-b-PEO(OH)12, constituted of a hydrophobic poly(ethoxyethyl glycidol ether) inner core and a hydrophilic poly(ethylene oxide) outer layer, has been successfully synthesized by the living anionic ring-opening polymerization method. The intermediates and targeted products were characterized with 1H NMR spectroscopy and gel permeation chromatography. The application on drug delivery of dendrimer-like diblock copolymer PEEGE-G2-b-PEO(OH)12 using DOX as a model drug was also studied. The drug loading content and encapsulation efficiency were found at 13.07% and 45.75%, respectively. In vitro release experiment results indicated that the drug-loaded micelles exhibited a sustained release behavior under acidic media.

  3. Synthesis and self-assembly of amphiphilic gradient copolymer via RAFT emulsifier-free emulsion polymerization.

    Science.gov (United States)

    Chen, Yanjun; Luo, Wen; Wang, Yifeng; Sun, Chong; Han, Mei; Zhang, Chaocan

    2012-03-01

    The amphiphilic gradient copolymers of 2,2,2-trifluoroethyl methacrylate (TFEMA) and acrylic acid (AA) have been synthesized by using amphiphilic RAFT agent via emulsifier-free emulsion polymerization with a starved feed method of adding TFEMA. Different cosolvents are added into polymerization system to inhibit AA's homopolymerization of in aqueous phase. RAFT polymerization kinetics under different reaction conditions are discussed in detail. (1)H NMR results indicate that the obtained copolymer has a chain structure with AA segments gradually changing to TFEMA segments. The copolymer latexes exhibit good pH stability (pH value from 5 to 14) and Ca(2+) stability. The self-assembly behavior of gradient copolymers in selective solvents are observed and studied by transmission electron microscopy. All the copolymers can form spherical micelles, but the homogeneity and size of micelles are different. Copyright © 2011 Elsevier Inc. All rights reserved.

  4. Synthesis of amphiphilic aminated inulin via 'click chemistry' and evaluation for its antibacterial activity.

    Science.gov (United States)

    Dong, Fang; Zhang, Jun; Yu, Chunwei; Li, Qing; Ren, Jianming; Wang, Gang; Gu, Guodong; Guo, Zhanyong

    2014-09-15

    Inulins are a group of abundant, water-soluble, renewable polysaccharides, which exhibit attractive bioactivities and natural properties. Improvement such as chemical modification of inulin is often performed prior to further utilization. We hereby presented a method to modify inulin at its primary hydroxyls to synthesize amphiphilic aminated inulin via 'click chemistry' to facilitate its chemical manipulation. Additionally, its antibacterial property against Staphylococcus aureus (S. aureus) was also evaluated and the best inhibitory index against S. aureus was 58% at 1mg/mL. As the amphiphilic aminated inulin is easy to prepare and exhibits improved bioactivity, this material may represent as an attractive new platform for chemical modifications of inulin. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Micelles by self-assembling peptide-conjugate amphiphile: synthesis and structural characterization.

    Science.gov (United States)

    Accardo, Antonella; Tesauro, Diego; Del Pozzo, Luigi; Mangiapia, Gaetano; Paduano, Luigi; Morelli, Giancarlo

    2008-08-01

    The chemical synthesis by solid-phase methods of a novel amphiphilic peptide, peptide-conjugate amphiphile (PCA), containing in the same molecule three different functions: (i) the N,N-bis[2-[bis(carboxy-ethyl)amino]ethyl]-L-glutamic acid (DTPAGlu) chelating agent, (ii) the CCK8 bioactive peptide, and (iii) a hydrophobic moiety containing four alkyl chains with 18 carbon atoms each, is reported. In water solution at pH 7.4, PCA self-assembles in very stable micelles at very low concentration [critical micellar concentration (cmc) values of 5 x 10(-7) mol kg(-1)] as confirmed by fluorescence spectroscopy. The structural characterization, obtained with small-angle neutron scattering (SANS) measurements, indicates that the aggregates are substantially represented by ellipsoidal micelles with an aggregation number of 39 +/- 2 and the two micellar axes of about 52 and 26 A. Copyright (c) 2008 European Peptide Society and John Wiley & Sons, Ltd.

  6. Terpene and dextran renewable resources for the synthesis of amphiphilic biopolymers.

    Science.gov (United States)

    Alvès, Marie-Hélène; Sfeir, Huda; Tranchant, Jean-François; Gombart, Emilie; Sagorin, Gilles; Caillol, Sylvain; Billon, Laurent; Save, Maud

    2014-01-13

    The present work shows the synthesis of amphiphilic polymers based on the hydrophilic dextran and the hydrophobic terpenes as renewable resources. The first step concerns the synthesis of functional terpene molecules by thiol-ene addition chemistry involving amino or carboxylic acid thiols and dihydromyrcenol terpene. The terpene-modified polysaccharides were subsequently synthesized by coupling the functional terpenes with dextran. A reductive amination step produced terpene end-modified dextran with 94% of functionalization, while the esterification step produced three terpene-grafted dextrans with a number of terpene units per dextran of 1, 5, and 10. The amphiphilic renewable grafted polymers were tested as emulsifiers for the stabilization of liquid miniemulsion of terpene droplets dispersed in an aqueous phase. The average hydrodynamic diameter of the stable droplets was observed at about 330 nm.

  7. Trapping of polycyclic aromatic hydrocarbons by amphiphilic cyclodextrin functionalized polypropylene nonwovens

    DEFF Research Database (Denmark)

    Lumholdt, Ludmilla; Nielsen, Ronnie Bo Højstrup; Larsen, Kim Lambertsen

    Recently, there has been an augmented focus on the increasing amount of pesticides, drug residues and endocrine disruptors present in waste and drinking water1. These pollutants represent a challenge in water purification since they may be hazardous to human health even in low doses2. Cyclodextrins...... of the textile fibers. In this study we present the ability of amphiphilic CD coated polypropylene nonwovens to trap 8 different polycyclic aromatic hydrocarbons/endocrine disruptors from aqueous solutions thus demonstrating the potential of using the amphiphilic cyclodextrins for water purification....... (CDs) are known to be able to form inclusion complexes with a large range of the unwanted pollutantse.g. 3 but in order to utilise this ability to purify water, the CDs must be immobilised on a surface, for instance, a membrane filter. We have developed a simple and fast method...

  8. A theoretical study of colloidal forces near an amphiphilic polymer brush

    Science.gov (United States)

    Wu, Jianzhong

    2011-03-01

    Polymer-based ``non-stick'' coatings are promising as the next generation of effective, environmentally-friendly marine antifouling systems that minimize nonspecific adsorption of extracellular polymeric substances (EPS). However, design and development of such systems are impeded by the poor knowledge of polymer-mediated interactions of biomacromolecules with the protected substrate. In this work, a polymer density functional theory (DFT) is used to predict the potential of mean force between spherical biomacromolecules and amphiphilic copolymer brushes within a coarse-grained model that captures essential nonspecific interactions such as the molecular excluded volume effects and the hydrophobic energies. The relevance of theoretical results for practical control of the EPS adsorption is discussed in terms of the efficiency of different brush configurations to prevent biofouling. It is shown that the most effective antifouling surface may be accomplished by using amphiphilic brushes with a long hydrophilic backbone and a hydrophobic end at moderate grafting density.

  9. Quantifying the energetics of cooperativity in a ternary protein complex

    DEFF Research Database (Denmark)

    Andersen, Peter S; Schuck, Peter; Sundberg, Eric J

    2002-01-01

    and mathematical modeling to describe the energetics of cooperativity in a trimolecular protein complex. As a model system for quantifying cooperativity, we studied the ternary complex formed by the simultaneous interaction of a superantigen with major histocompatibility complex and T cell receptor, for which...... a structural model is available. This system exhibits positive and negative cooperativity, as well as augmentation of the temperature dependence of binding kinetics upon the cooperative interaction of individual protein components in the complex. Our experimental and theoretical analysis may be applicable...... to other systems involving cooperativity....

  10. Implementation of DFT application on ternary optical computer

    Science.gov (United States)

    Junjie, Peng; Youyi, Fu; Xiaofeng, Zhang; Shuai, Kong; Xinyu, Wei

    2018-03-01

    As its characteristics of huge number of data bits and low energy consumption, optical computing may be used in the applications such as DFT etc. which needs a lot of computation and can be implemented in parallel. According to this, DFT implementation methods in full parallel as well as in partial parallel are presented. Based on resources ternary optical computer (TOC), extensive experiments were carried out. Experimental results show that the proposed schemes are correct and feasible. They provide a foundation for further exploration of the applications on TOC that needs a large amount calculation and can be processed in parallel.

  11. A review on ternary vanadate one-dimensional nanomaterials.

    Science.gov (United States)

    Pei, Li Z; Wang, Shuai; Liu, Han D; Pei, Yin Q

    2014-01-01

    Ternary vanadate one-dimensional nanomaterials exhibit great application potential in the fields of lithium ion batteries, photocatalysis and electrochemical sensors owing to their good electrochemical and photocatalytic properties. The article reviews the recent progress and patents on the vanadate one-dimensional nanomaterials. The synthesis of the vanadate nanorods, nanobelts and nanotubes by hydrothermal method, template method and room temperature wet chemical process is demonstrated. The application of the vanadate one-dimensional nanomaterials for lithium ion batteries, electrochemical sensors and photocatalysis is discussed. The possible development direction of the vanadate one-dimensional nanomaterials for the synthesis and application is also analyzed.

  12. Impact of ionizing radiation on physicochemical and biological properties of an amphiphilic macromolecule

    OpenAIRE

    Gu, Li; Zablocki, Kyle; Lavelle, Linda; Bodnar, Stanko; Halperin, Frederick; Harper, Ike; Moghe, Prabhas V.; Uhrich, Kathryn E.

    2012-01-01

    An amphiphilic macromolecule (AM) was exposed to ionizing radiation (both electron beam and gamma) at doses of 25 kGy and 50 kGy to study the impact of these sterilization methods on the physicochemical properties and bioactivity of the AM. Proton nuclear magnetic resonance and gel permeation chromatography were used to determine the chemical structure and molecular weight, respectively. Size and zeta potential of the micelles formed from AMs in aqueous media were evaluated by dynamic light s...

  13. Amphiphilic Perylene-Calix[4]arene hybrids:synthesis and tunable self-assembly

    OpenAIRE

    Rodler, Fabian; Schade, Boris; Jaeger, Christof M.; Backes, Susanne; Hampel, Frank; Boettcher, Christoph; Clark, Timothy; Hirsch, Andreas

    2015-01-01

    The first highly water-soluble perylene–calix[4]arene hybrid with the calixarene scaffold acting as a structure-determining central platform is presented. In this tetrahedrally shaped amphiphilic architecture the hydrophilic and hydrophobic subunits are oriented at the opposite side of the calixarene platform. The hydrophobic part contains the two perylene diimide moieties, which enable strong π–π interactions in self-assembly processes. Two hydrophilic Newkome-type dendrons provide sufficien...

  14. Structure of adsorption layers of amphiphilic copolymers on inorganic or organic particle surfaces

    OpenAIRE

    Bulychev, Nikolay; Dervaux, Bart; Dimberger, Klaus; Zubov, Vitali; Du Prez, Filip; Eisenbach, Claus D

    2010-01-01

    The structure of adsorption layers of amphiphilic block and block-like copolymers of poly(isobornyl acrylate) and poly(acrylic acid) on the surface of hydrophilic titanium dioxide and hydrophobic copper phthalocyanine (CuPc) pigments in an aqueous studied by the electrokinetic sonic amplitude (ESA) method. The electroacoustic behaviour of the polyelectrolyte block copolymer-coated particles could be described in the context of the polymer gel layer theory. The polymer layer around the particl...

  15. Novel Amphiphilic copolymers and design of smart nanoparticule for triggered drug delivery systems

    OpenAIRE

    Cajot, Sébastien; Jérôme, Christine

    2009-01-01

    Over the last decade, polymer micelles attracted an increasing interest in drug pharmaceutical research because they could be used as efficient drug delivery systems. Micelles of amphiphilic block copolymers are supramolecular core-shell type assemblies of tens of nanometers in diameter. In principle, the micelles core is usually constructed with biodegradable hydrophobic polymers such as aliphatic polyesters, e.g. poly(epsilon-caprolactone) (PCL), which serves as a reservoir for the inc...

  16. Amphiphilic Cellulose Ethers Designed for Amorphous Solid Dispersion via Olefin Cross-Metathesis.

    Science.gov (United States)

    Dong, Yifan; Mosquera-Giraldo, Laura I; Taylor, Lynne S; Edgar, Kevin J

    2016-02-08

    The design of cellulose ether-based amphiphiles has been difficult and limited because of the harsh conditions typically required for appending ether moieties to cellulose. Olefin cross-metathesis recently has been shown to be a valuable approach for appending a variety of functional groups to cellulose ethers and esters, provided that an olefin handle for metathesis can be attached. This synthetic pathway gives access to these functional derivatives under very mild conditions and at high efficiency. Modification of ethyl cellulose by metathesis to prepare useful derivatives, for example, for solubility and bioavailability enhancement of drugs by amorphous solid dispersion (ASD), has been limited by the low DS(OH) of commercial ethyl cellulose derivatives. This is problematic because ethyl cellulose is otherwise a very attractive substrate for synthesis of amphiphilic derivatives by olefin metathesis. Herein we explore two methods for opening up this design space for ether-based amphiphiles, for example, permitting synthesis of more hydrophilic derivatives. One approach is to start with the more hydrophilic commercial methyl cellulose, which contains much higher DS(OH) and therefore is better suited for introduction of high DS of olefin metathesis "handles". In another approach, we explored a homogeneous one-pot synthesis methodology from cellulose, where controlled DS of ethyl groups was introduced at the same time as the ω-unsaturated alkyl groups, thereby permitting complete control of DS(OH), DS(Et), and ultimately DS of the functional group added by metathesis. We describe the functionalized derivatives available by these successful approaches. In addition, we explore new methods for reduction of the unsaturation in initial metathesis products to provide robust methods for enhancing product stability against further radical-catalyzed reactions. We demonstrate initial evidence that the products show strong promise as amphiphilic matrix polymers for amorphous

  17. Protein resistance efficacy of PEO-silane amphiphiles: Dependence on PEO-segment length and concentration.

    Science.gov (United States)

    Rufin, Marc A; Barry, Mikayla E; Adair, Paige A; Hawkins, Melissa L; Raymond, Jeffery E; Grunlan, Melissa A

    2016-09-01

    In contrast to modification with conventional PEO-silanes (i.e. no siloxane tether), silicones with dramatically enhanced protein resistance have been previously achieved via bulk-modification with poly(ethylene oxide) (PEO)-silane amphiphiles α-(EtO)3Si(CH2)2-oligodimethylsiloxane13-block-PEOn-OCH3 when n=8 and 16 but not when n=3. In this work, their efficacy was evaluated in terms of optimal PEO-segment length and minimum concentration required in silicone. For each PEO-silane amphiphile (n=3, 8, and 16), five concentrations (5, 10, 25, 50, and 100μmol per 1g silicone) were evaluated. Efficacy was quantified in terms of the modified silicones' abilities to undergo rapid, water-driven surface restructuring to form hydrophilic surfaces as well as resistance to fibrinogen adsorption. Only n=8 and 16 were effective, with a lower minimum concentration in silicone required for n=8 (10μmol per 1g silicone) versus n=16 (25μmol per 1g silicone). Silicone is commonly used for implantable medical devices, but its hydrophobic surface promotes protein adsorption which leads to thrombosis and infection. Typical methods to incorporate poly(ethylene oxide) (PEO) into silicones have not been effective due to the poor migration of PEO to the surface-biological interface. In this work, PEO-silane amphiphiles - comprised of a siloxane tether (m=13) and variable PEO segment lengths (n=3, 8, 16) - were blended into silicone to improve its protein resistance. The efficacy of the amphiphiles was determined to be dependent on PEO length. With the intermediate PEO length (n=8), water-driven surface restructuring and resulting protein resistance was achieved with a concentration of only 1.7wt%. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  18. Self-organization of amphiphilic block copolymers in the presence of water: A mesoscale simulation

    Science.gov (United States)

    Komarov, Pavel V.; Veselov, Igor N.; Khalatur, Pavel G.

    2014-06-01

    Using dissipative particle dynamics, we analyze the suitability of amphiphilic diblock copolymers as a material for high-performance proton conducting membranes of fuel cells. It is shown that the topology of water channel network within hydrated block copolymer-based membranes can be controlled by varying the copolymer blocks length. In particular, our simulations predict the formation of bicontinuous cubic phases for hydrophilic, hydrophobic blocks, and water. The interfaces between microphase-separated subphases form triply periodic minimal surfaces.

  19. A comparative study of the physicochemical properties of perfluorinated and hydrogenated amphiphiles.

    Science.gov (United States)

    Blanco, Elena; González-Pérez, Alfredo; Ruso, Juan M; Pedrido, Rosa; Prieto, Gerardo; Sarmiento, Félix

    2005-08-01

    In this work we studied and compared the physicochemical properties of perfluorinated (sodium perfluoroheptanoate, C7FONa, and perfluorooctanoate, C8FONa) and hydrogenated (sodium octanoate, C8HONa, decanoate, C10HONa, and dodecanoate, C12HONa) amphiphiles. First, we determined their Krafft points to study the solubility and appropriate temperature range of micellization of these compounds. The critical micelle concentration (cmc) and ionization degree of micellization (beta) as a function of temperature (T) were estimated from conductivity data. Plots of cmc vs T appear to follow the typical U-shaped curve with a minimum T(min). The results show that the surfactants with CF2/CH2 ratio of 1.5 between alkyl chains (C12HONa-C8FONa and C10HONa-C7FONa) have nearly the same minimum value for cmc against temperature. The comparison between the cmc of hydrogenated amphiphiles and the corresponding perfluorinated amphiphiles must be done at this point. Thermodynamic functions of micellization were obtained by applying different theoretical models and choosing the one that best fit our experimental data. Although perfluorinated and hydrogenated amphiphiles present similar thermodynamic behavior, we have found a variation of 1.3 to 1.7 in the CF2/CH2 ratio, which did not remain constant with temperature. In the second part of this study the apparent molar volumes and adiabatic compressibilities were determined from density and ultrasound velocity measurements. Apparent molar volumes at infinite dilution presented the ratio 1.5 between alkyl chains again. However, apparent molar volumes upon micellization for sodium perfluoroheptanoate indicated a different aggregation pattern.

  20. An improved thermodiffusion model for ternary mixtures using Fujita's free volume theory

    Science.gov (United States)

    Abbasi, Alireza; Saghir, M. Ziad; Kawaji, Masahiro

    2011-09-01

    Thermodiffusion along molecular diffusion is one of the major mechanisms of transport phenomena. They have an important role in displacement of hydrocarbon fluid components in an oil reservoir. Free volume controls the diffusivity of the molecule in diffusion-limited systems. It states that the transfer kinetics of molecules depends greatly on molecular size and shape as well as the concentration. A new proposed model based on Fujita-type model is used to predict the thermodiffusion coefficients in ternary mixtures such as n-dodecane (nC12), n-butane (nC4), methane (C1), n-dodecane (nC12), isobutylbenzene (IBB), tetrahydronaphtalene (THN) and n-octane (C8), n-decane (nC10), 1-methylnaphtalene (MN). The ratio of evaporation energy to activation energy required for estimating the thermodiffusion coefficients is calculated by the available free volume theory. In particular, the combination of available free volume theory and Shukla and Firoozabadi's model is applied to predict the thermodiffusion coefficient. The results show a good performance of the new approach in estimating the thermodiffusion coefficients.

  1. Synthesis, micellization behavior and alcohol induced amphipathic cellulose film of cellulose-based amphiphilic surfactant

    Science.gov (United States)

    Yang, Fang; Liu, Ya-nan; Yu, Jian-ling; Li, Hai-peng; Li, Gang

    2015-08-01

    This paper presented a novel preparation method of the cellulose-based amphiphilic surfactant, and the surfactant was used to prepare amphipathic cellulose membrane. The native cotton cellulose was tailored to cellulose segments in ionic liquid 1-butyl-3-methylimidazolium chloride. Then, the hydrophobic and hydrophilic modification of cellulose segments were carried out by esterification and graft polymerization of the ɛ-caprolactone (ɛ-CL) monomer onto the hydroxyl group of cellulose as well as sulphonation with sulfamic acid. The amphipathic cellulose membrane was made by cellulose-based amphiphilic surfactant cross-linking with glutaraldehyde. The molecular structure of amphipathic cellulose surfactant was confirmed by FT-IR, and its surface active properties were investigated by Wilhelmy plate method and Steady-state fluorescence probe method, respectively. Experimental results showed that cellulose-based amphiphilic surfactant caused low interfacial tension of 48.62 mN/m and its critical micelle concentration (cmc) value was 0.65 wt% when the grafting ratio of cellulose-g-PCL (poly-caprolactone) was 25.40%. The contact angle between a droplet of water and the surface of membrane was 90.84o, and the surface free energy of the alcohol induced cellulose membrane was 15.7 mJ/m2. This study may help increase using natural and biodegradable surface-activity materials with improved properties as surfactants.

  2. Design and application of cationic amphiphilic β-cyclodextrin derivatives as gene delivery vectors

    Science.gov (United States)

    Wan, Ning; Huan, Meng-Lei; Ma, Xi-Xi; Jing, Zi-Wei; Zhang, Ya-Xuan; Li, Chen; Zhou, Si-Yuan; Zhang, Bang-Le

    2017-11-01

    The nano self-assembly profiles of amphiphilic gene delivery vectors could improve the density of local cationic head groups to promote their DNA condensation capability and enhance the interaction between cell membrane and hydrophobic tails, thus increasing cellular uptake and gene transfection. In this paper, two series of cationic amphiphilic β-cyclodextrin (β-CD) derivatives were designed and synthesized by using 6-mono-OTs-β-CD (1) as the precursor to construct amphiphilic gene vectors with different building blocks in a selective and controlled manner. The effect of different type and degree of cationic head groups on transfection and the endocytic mechanism of β-CD derivatives/DNA nanocomplexes were also investigated. The results demonstrated that the designed β-cyclodextrin derivatives were able to compact DNA to form stable nanocomplexes and exhibited low cytotoxicity. Among them, PEI-1 with PEI head group showed enhanced transfection activity, significantly higher than commercially available agent PEI25000 especially in the presence of serum, showing potential application prospects in clinical trials. Moreover, the endocytic uptake mechanism involved in the gene transfection of PEI-1 was mainly through caveolae-mediated endocytosis, which could avoid the lysosomal degradation of loaded gene, and had great importance for improving gene transfection activity.

  3. Precisely Size-Tunable Monodisperse Hairy Plasmonic Nanoparticles via Amphiphilic Star-Like Block Copolymers.

    Science.gov (United States)

    Chen, Yihuang; Yoon, Young Jun; Pang, Xinchang; He, Yanjie; Jung, Jaehan; Feng, Chaowei; Zhang, Guangzhao; Lin, Zhiqun

    2016-12-01

    In situ precision synthesis of monodisperse hairy plasmonic nanoparticles with tailored dimensions and compositions by capitalizing on amphiphilic star-like diblock copolymers as nanoreactors are reported. Such hairy plasmonic nanoparticles comprise uniform noble metal nanoparticles intimately and perpetually capped by hydrophobic polymer chains (i.e., "hairs") with even length. Interestingly, amphiphilic star-like diblock copolymer nanoreactors retain the spherical shape under reaction conditions, and the diameter of the resulting plasmonic nanoparticles and the thickness of polymer chains situated on the surface of the nanoparticle can be readily and precisely tailored. These hairy nanoparticles can be regarded as hard/soft core/shell nanoparticles. Notably, the polymer "hairs" are directly and permanently tethered to the noble metal nanoparticle surface, thereby preventing the aggregation of nanoparticles and rendering their dissolution in nonpolar solvents and the homogeneous distribution in polymer matrices with long-term stability. This amphiphilic star-like block copolymer nanoreactor-based strategy is viable and robust and conceptually enables the design and synthesis of a rich variety of hairy functional nanoparticles with new horizons for fundamental research on self-assembly and technological applications in plasmonics, catalysis, energy conversion and storage, bioimaging, and biosensors. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Morphological Evolution of Self-Assembled Structures Induced by the Molecular Architecture of Supra-Amphiphiles.

    Science.gov (United States)

    Wang, Juan; Li, Boxuan; Wang, Xing; Yang, Fei; Shen, Hong; Wu, Decheng

    2016-12-27

    A series of telechelic supramolecular amphiphiles [POSS-Azo 8 @(β-CD-PDMAEMA) 1→8 ] was accomplished by orthogonally coupling the multiarm host polymer β-cyclodextrin-poly(dimethylaminoethyl methacrylate) (β-CD-PDMAEMA) with an octatelechelic guest molecule azobenzene modified-polyhedral oligomeric silsesquioxanes (POSS-Azo 8 ) under different host-guest ratios. These telechelic supramolecular amphiphiles possess a rigid core and flexible corona. Increasing the multiarm host polymer coupled onto the rigid POSS core made the molecular architecture tend to be symmetrical and spherical. POSS-Azo 8 @[β-CD-PDMAEMA] 1→8 could self-assemble into diverse morphologies evolving from spherical micelles, wormlike micelles, and branched aggregates to bowl-shaped vesicles. Distinct from the traditional linear amphiphilic polymers, we discovered that the self-assembly of POSS-Azo 8 @[β-CD-PDMAEMA] 1→8 was dominantly regulated by their molecular architectures instead of hydrophilicity, which has also been verified using computer simulation results.

  5. The effect of amphiphilic siloxane oligomers on fibroblast and keratinocyte proliferation and apoptosis.

    Science.gov (United States)

    Lynam, Emily C; Xie, Yan; Loli, Bree; Dargaville, Tim R; Leavesley, David I; George, Graeme A; Upton, Zee

    2010-11-01

    The formation of hypertrophic scars (HSF) is a frequent medical outcome of wound repair and often requires further therapy with treatments such as silicone gel sheets (SGS) or apoptosis-inducing agents, including bleomycin. Although widely used, knowledge regarding SGS and their mode of action is limited. Preliminary research has shown that small amounts of amphiphilic silicone present in SGS have the ability to move into skin during treatment. We demonstrate herein that a commercially available analogue of these amphiphilic siloxane species, the rake copolymer GP226, decreases collagen synthesis on exposure to cultures of fibroblasts derived from HSF. By size exclusion chromatography, GP226 was found to be a mixture of siloxane species, containing five fractions of different molecular weight. By studies of collagen production, cell viability and proliferation, it was revealed that a low molecular weight fraction (fraction IV) was the most active, reducing the number of viable cells present after treatment and thereby reducing collagen production as a result. On exposure of fraction IV to human keratinocytes, viability and proliferation were also significantly affected. HSF undergoing apoptosis after application of fraction IV were also detected via real-time microscopy and by using the TUNEL assay. Taken together, these data suggests that these amphiphilic siloxanes could be potential non-invasive substitutes to apoptotic-inducing chemical agents that are currently used as scar treatments.

  6. Self-Assembly of Discrete Metal Complexes in Aqueous Solution via Block Copolypeptide Amphiphiles

    Directory of Open Access Journals (Sweden)

    Timothy J. Deming

    2013-01-01

    Full Text Available The integration of discrete metal complexes has been attracting significant interest due to the potential of these materials for soft metal-metal interactions and supramolecular assembly. Additionally, block copolypeptide amphiphiles have been investigated concerning their capacity for self-assembly into structures such as nanoparticles, nanosheets and nanofibers. In this study, we combined these two concepts by investigating the self-assembly of discrete metal complexes in aqueous solution using block copolypeptides. Normally, discrete metal complexes such as [Au(CN2]−, when molecularly dispersed in water, cannot interact with one another. Our results demonstrated, however, that the addition of block copolypeptide amphiphiles such as K183L19 to [Au(CN2]− solutions induced one-dimensional integration of the discrete metal complex, resulting in photoluminescence originating from multinuclear complexes with metal-metal interactions. Transmission electron microscopy (TEM showed a fibrous nanostructure with lengths and widths of approximately 100 and 20 nm, respectively, which grew to form advanced nanoarchitectures, including those resembling the weave patterns of Waraji (traditional Japanese straw sandals. This concept of combining block copolypeptide amphiphiles with discrete coordination compounds allows the design of flexible and functional supramolecular coordination systems in water.

  7. Shape Recovery with Concomitant Mechanical Strengthening of Amphiphilic Shape Memory Polymers in Warm Water.

    Science.gov (United States)

    Zhang, Ben; DeBartolo, Janae E; Song, Jie

    2017-02-08

    Maintaining adequate or enhancing mechanical properties of shape memory polymers (SMPs) after shape recovery in an aqueous environment are greatly desired for biomedical applications of SMPs as self-fitting tissue scaffolds or minimally invasive surgical implants. Here we report stable temporary shape fixing and facile shape recovery of biodegradable triblock amphiphilic SMPs containing a poly(ethylene glycol) (PEG) center block and flanking poly(lactic acid) or poly(lactic-co-glycolic acid) blocks in warm water, accompanied by concomitant enhanced mechanical strengths. Differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WXRD), and small-angle X-ray scattering (SAXS) analyses revealed that the unique stiffening of the amphiphilic SMPs upon hydration was due to hydration-driven microphase separation and PEG crystallization. We further demonstrated that the chemical composition of degradable blocks in these SMPs could be tailored to affect the persistence of hydration-induced stiffening upon subsequent dehydration. These properties combined open new horizons for these amphiphilic SMPs for smart weight-bearing in vivo applications (e.g., as self-fitting intervertebral discs). This study also provides a new material design strategy to strengthen polymers in aqueous environment in general.

  8. Physical deposition behavior of stiff amphiphilic polyelectrolytes in an external electric field

    Science.gov (United States)

    Hu, Dongmei; Zuo, Chuncheng; Cao, Qianqian; Chen, Hongli

    2017-08-01

    Coarse-grained molecular dynamics simulations are conducted to study the physical deposition behavior of stiff amphiphilic polyelectrolytes (APEs) in an external electric field. The effects of chain stiffness, the charge distribution of a hydrophilic block, and electric field strength are investigated. Amphiphilic multilayers, which consist of a monolayer of adsorbed hydrophilic monomers (HLMs), a hydrophobic layer, and another hydrophilic layer, are formed in a selective solvent. All cases exhibit locally ordered hydrophilic monolayers. Two kinds of hydrophobic micelles are distinguished based on local structures. Stripe and network hydrophobic patterns are formed in individual cases. Increasing the chain stiffness decreases the thickness of the deposited layer, the lateral size of the hydrophobic micelles, and the amount of deposition. Increasing the number of positively charged HLMs in a single chain has the same effect as increasing chain stiffness. Moreover, when applied normally to the substrate, the electric field compresses the deposited structures and increases the amount of deposition by pulling more PEs toward the substrate. A stronger electric field also facilitates the formation of a thinner and more ordered hydrophilic adsorption layer. These estimates help us explore how to tailor patterned nano-surfaces, nano-interfaces, or amphiphilic nanostructures by physically depositing semi-flexible APEs which is of crucial importance in physical sciences, life sciences and nanotechnology.

  9. Amphiphilic carbon dots for sensitive detection, intracellular imaging of Al{sup 3+}

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Depeng [State Key Laboratory of Separation Membranes and Membrane Processes, School of Environmental and Chemical Engineering, Tianjin Polytechnic University, Tianjin 300387 (China); Yan, Fanyong, E-mail: yanfanyong@tjpu.edu.cn [State Key Laboratory of Separation Membranes and Membrane Processes, School of Environmental and Chemical Engineering, Tianjin Polytechnic University, Tianjin 300387 (China); Luo, Yunmei [Department of Pharmacology/Key Laboratory for Basic Pharmacology of Ministry of Education, Zunyi Medical College, Guizhou 563000 (China); Ye, Qianghua; Zhou, Siyushan [State Key Laboratory of Separation Membranes and Membrane Processes, School of Environmental and Chemical Engineering, Tianjin Polytechnic University, Tianjin 300387 (China); Chen, Li, E-mail: Chenlis@tjpu.edu.cn [State Key Laboratory of Separation Membranes and Membrane Processes, School of Environmental and Chemical Engineering, Tianjin Polytechnic University, Tianjin 300387 (China)

    2017-02-08

    In this paper, a simple and effective method was designed to synthesize hydrophobic carbon dots. Subsequently, amphiphilic fluorescent carbon dots (A-CDs) were synthesized by further surface modification. The result A-CDs show excellent optical properties with a quantum yield of 16.9%. It was interestingly found that morin (MR) and its fluorescent metal-ion complex (MR-Al{sup 3+}) can successfully coordinate on the surface of A-CDs, the emission of A-CDs completely overlapped the absorption peak of MR-Al{sup 3+}. Thus, the prepared A-CDs can be used as an effective fluorescent probe for Al{sup 3+} based on a fluorescence resonance energy transfer process. The sensing platform can realize real-time detection of Al{sup 3+} within 0.5 min. The fluorescence signals of the system were linearly correlated with the concentration of Al{sup 3+} over a range of 8–20 μM, with a detection limit of 0.113 μM. The method was also successfully applied to image the distribution of Al{sup 3+} in Human Umbilical Vein Endothelial Cells. - Highlights: • Amphiphilic carbon dots were obtained by simply modifying hydrophobic carbon dots. • Amphiphilic carbon dots/morin-Al{sup 3+} was used as a selective turn-on probe for Al{sup 3+}. • The method was employed to intracellular imaging Al{sup 3+} in living cells.

  10. Beyond paraquats: dialkyl 3,3'- and 3,4'-bipyridinium amphiphiles as antibacterial agents.

    Science.gov (United States)

    Ator, Laura E; Jennings, Megan C; McGettigan, Amanda R; Paul, Jared J; Wuest, William M; Minbiole, Kevin P C

    2014-08-15

    Dialkyl 4,4'-bipyridinium compounds, known as 'paraquats' (PQs), have a long history of use as herbicides, as redox indicators, and more recently as potent antibacterial agents. However, due to their ability to form reactive oxygen species (ROS) in vivo, PQs are also known to be toxic. We proposed that altering the electrochemical properties of PQ, specifically by preparing isomeric bipyridinium structures with 3,3'- and 3,4'-substitution of the nitrogen heteroatoms on the biaryl core, would maintain antibacterial activity, yet decrease toxicity. We have thus prepared a series of 17 amphiphiles, dubbed 'metaquat' (MQ) and 'parametaquat' (PMQ), respectively, and investigated their antibacterial and electrochemical properties. Optimal inhibition of bacterial growth was observed in symmetric, biscationic structures; minimum inhibitory concentration (MIC) values measured as low as 0.5 μM against both Gram-positive and Gram-negative bacteria for the compound PMQ-11,11. Electrochemical analysis demonstrated the redox properties of the dialkyl 3,3'- and 3,4'-bipyridinium amphiphiles to be distinct from those of the 4,4'-bipyridinium isomer. Thus MQ and PMQ amphiphiles maintain the strong antibacterial activity of the PQ isomers, but show promise for reduced ROS toxicity. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Synthesis and characterization of amorphous mesoporous silica using TEMPO-functionalized amphiphilic templates

    Energy Technology Data Exchange (ETDEWEB)

    Vries, Wilke de [Institute of Organic Chemistry, Westfälische Wilhelms-Universität Münster, Corrensstrasse 40, 48149 Münster (Germany); Doerenkamp, Carsten; Zeng, Zhaoyang [Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 28/30, 48149 Münster (Germany); Oliveira, Marcos de [Instituto de Física em Sao Paulo, Universidade de Sao Paulo, Av. Trabalhador Saocarlense 400, Sao Carlos, S.P. 13560 590 (Brazil); Niehaus, Oliver; Pöttgen, Rainer [Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 28/30, 48149 Münster (Germany); Studer, Armido, E-mail: studer@uni-muenster.de [Institute of Organic Chemistry, Westfälische Wilhelms-Universität Münster, Corrensstrasse 40, 48149 Münster (Germany); Eckert, Hellmut, E-mail: eckerth@uni-muenster.de [Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 28/30, 48149 Münster (Germany); Instituto de Física em Sao Paulo, Universidade de Sao Paulo, Av. Trabalhador Saocarlense 400, Sao Carlos, S.P. 13560 590 (Brazil)

    2016-05-15

    Inorganic–organic hybrid materials based on amorphous mesoporous silica containing organized nitroxide radicals within its mesopores have been prepared using the micellar self-assembly of TEOS solutions containing the nitroxide functionalized amphiphile (4-(N,N-dimethyl-N-hexadecylammonium)-2,2,6, 6-tetramethyl-piperidin-N-oxyl-iodide) (CAT-16). This template has been used both in its pure form and in various mixtures with cetyl trimethylammonium bromide (CTAB). The samples have been characterized by chemical analysis, N{sub 2} sorption studies, magnetic susceptibility measurements, and various spectroscopic methods. While electron paramagnetic resonance (EPR) spectra indicate that the strength of the intermolecular spin–spin interactions can be controlled via the CAT-16/CTAB ratio, nuclear magnetic resonance (NMR) data suggest that these interactions are too weak to facilitate cooperative magnetism. - Graphical abstract: The amphiphilic radical CAT-16 is used as a template for the synthesis of amorphous mesoporous silica. The resulting paramagnetic hybrid materials are characterized by BET, FTIR, NMR, EPR and magnetic susceptibility studies. - Highlights: • Amphiphilic CAT-16 as a template for mesoporous silica. • Comprehensive structural characterization by BET, FTIR; EPR and NMR. • Strength of radical-radical interactions tuable within CAT-16/CTAB mixtures.

  12. Ternary System with Controlled Structure: A New Strategy toward Efficient Organic Photovoltaics.

    Science.gov (United States)

    Cheng, Pei; Wang, Rui; Zhu, Jingshuai; Huang, Wenchao; Chang, Sheng-Yung; Meng, Lei; Sun, Pengyu; Cheng, Hao-Wen; Qin, Meng; Zhu, Chenhui; Zhan, Xiaowei; Yang, Yang

    2018-02-01

    Recently, a new type of active layer with a ternary system has been developed to further enhance the performance of binary system organic photovoltaics (OPV). In the ternary OPV, almost all active layers are formed by simple ternary blend in solution, which eventually leads to the disordered bulk heterojunction (BHJ) structure after a spin-coating process. There are two main restrictions in this disordered BHJ structure to obtain higher performance OPV. One is the isolated second donor or acceptor domains. The other is the invalid metal-semiconductor contact. Herein, the concept and design of donor/acceptor/acceptor ternary OPV with more controlled structure (C-ternary) is reported. The C-ternary OPV is fabricated by a sequential solution process, in which the second acceptor and donor/acceptor binary blend are sequentially spin-coated. After the device optimization, the power conversion efficiencies (PCEs) of all OPV with C-ternary are enhanced by 14-21% relative to those with the simple ternary blend; the best PCEs are 10.7 and 11.0% for fullerene-based and fullerene-free solar cells, respectively. Moreover, the averaged PCE value of 10.4% for fullerene-free solar cell measured in this study is in great agreement with the certified one of 10.32% obtained from Newport Corporation. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Fullerene alloy formation and the benefits for efficient printing of ternary blend organic solar cells

    DEFF Research Database (Denmark)

    Angmo, Dechan; Bjerring, Morten; Nielsen, Niels Chr.

    2015-01-01

    with a third polymer component, the system exhibits pseudo-binary phase behaviour instead of the expected ternary phase behaviour. Our results experimentally confirm the earlier hypothesis that the unexpected composition average dependent IV-behaviour for these supposed ternary mixtures are indeed due to them...

  14. Using a Ternary Diagram to Display a System's Evolving Energy Distribution

    Science.gov (United States)

    Brazzle, Bob; Tapp, Anne

    2016-01-01

    A ternary diagram is a graphical representation used for systems with three components. They are familiar to mineralogists (who typically use them to categorize varieties of solid solution minerals such as feldspar) but are not yet widely used in the physics community. Last year the lead author began using ternary diagrams in his introductory…

  15. Visible and near-infrared light emitting calix[4]arene-based ternary lanthanide complexes

    NARCIS (Netherlands)

    Hebbink, G.A.; Klink, S.I.; Oude Alink, Patrick G.B.; van Veggel, F.C.J.M.

    2001-01-01

    In this article ternary lanthanide complexes consisting of a calix[4]arene unit and dibenzoylmethane (dbm) as the antenna are described. In the europium complex [(Eu)2]NO3 two solvent molecules are still coordinated to the ion, making substitution of them by the dbm antenna possible. In the ternary

  16. Calculated site substitution in ternary gamma'-Ni3Al: Temperature and composition effects

    DEFF Research Database (Denmark)

    Ruban, Andrei; Skriver, Hans Lomholt

    1997-01-01

    The temperature and composition dependence of the site substitution behavior of ternary additions to Ni3Al is examined on the basis of first-principles calculations of the total energies of ternary, partially ordered (gamma') alloys. The calculations are performed by means of the linear muffin...

  17. INTERVAL-VALUED INTUITIONISTIC FUZZY BI-IDEALS IN TERNARY SEMIRINGS

    Directory of Open Access Journals (Sweden)

    D. KRISHNASWAMY

    2016-04-01

    Full Text Available In this paper we introduce the notions of interval-valued fuzzy bi-ideal, interval-valued anti fuzzy bi-ideal and interval-valued intuitionistic fuzzy bi-ideal in ternary semirings and some of the basic properties of these ideals are investigated. We also introduce normal interval-valued intuitionistic fuzzy ideals in ternary semirings.

  18. Ternary-fission dynamics and asymmetries in reactions with polarized neutrons

    CERN Document Server

    Bunakov, V E

    2002-01-01

    Experimental results of measuring various asymmetries of charged-particles emission in ternary fission induced by polarized neutrons, namely parity nonconserving asymmetries, left-right asymmetries and triple-odd correlations are presented. It is demonstrated what kind of new information about the mechanism of ternary fission can be obtained from their analysis

  19. Factoring with qutrits: Shor's algorithm on ternary and metaplectic quantum architectures

    Science.gov (United States)

    Bocharov, Alex; Roetteler, Martin; Svore, Krysta M.

    2017-07-01

    We determine the cost of performing Shor's algorithm for integer factorization on a ternary quantum computer, using two natural models of universal fault-tolerant computing: (i) a model based on magic state distillation that assumes the availability of the ternary Clifford gates, projective measurements, classical control as its natural instrumentation set; (ii) a model based on a metaplectic topological quantum computer (MTQC). A natural choice to implement Shor's algorithm on a ternary quantum computer is to translate the entire arithmetic into a ternary form. However, it is also possible to emulate the standard binary version of the algorithm by encoding each qubit in a three-level system. We compare the two approaches and analyze the complexity of implementing Shor's period-finding function in the two models. We also highlight the fact that the cost of achieving universality through magic states in MTQC architecture is asymptotically lower than in generic ternary case.

  20. High-performance ternary blend polymer solar cells involving both energy transfer and hole relay processes

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Luyao; Chen, Wei; Xu, Tao; Yu, Luping

    2015-06-04

    The integration of multiple materials with complementary absorptions into a singlejunction device is regarded as an efficient way to enhance the power conversion efficiency (PCE) of organic solar cells (OSCs). However, due to increased complexity with one more component, only limited high performance ternary systems have been demonstrated previously. Here, we report an efficient ternary blend OSC with a PCE of 9.2%. We show for the first time that the third component can reduce surface trap densities in the ternary blend. Detailed studies unravel that the improved performance results from synergistic effects of enlarged open circuit voltage, suppressed trap assisted recombination, enhanced light absorption, increased hole extraction, efficient energy transfer, and better morphology. The novel working mechanism and high device performance demonstrate new insights and design guidelines for high performance ternary blend solar cells and suggest that ternary structure is a promising platform to boost the efficiency of OSCs.

  1. Fluid Shifts

    Science.gov (United States)

    Stenger, M. B.; Hargens, A. R.; Dulchavsky, S. A.; Arbeille, P.; Danielson, R. W.; Ebert, D. J.; Garcia, K. M.; Johnston, S. L.; Laurie, S. S.; Lee, S. M. C.; hide

    2017-01-01

    Introduction. NASA's Human Research Program is focused on addressing health risks associated with long-duration missions on the International Space Station (ISS) and future exploration-class missions beyond low Earth orbit. Visual acuity changes observed after short-duration missions were largely transient, but now more than 50 percent of ISS astronauts have experienced more profound, chronic changes with objective structural findings such as optic disc edema, globe flattening and choroidal folds. These structural and functional changes are referred to as the visual impairment and intracranial pressure (VIIP) syndrome. Development of VIIP symptoms may be related to elevated intracranial pressure (ICP) secondary to spaceflight-induced cephalad fluid shifts, but this hypothesis has not been tested. The purpose of this study is to characterize fluid distribution and compartmentalization associated with long-duration spaceflight and to determine if a relation exists with vision changes and other elements of the VIIP syndrome. We also seek to determine whether the magnitude of fluid shifts during spaceflight, as well as any VIIP-related effects of those shifts, are predicted by the crewmember's pre-flight status and responses to acute hemodynamic manipulations, specifically posture changes and lower body negative pressure. Methods. We will examine a variety of physiologic variables in 10 long-duration ISS crewmembers using the test conditions and timeline presented in the figure below. Measures include: (1) fluid compartmentalization (total body water by D2O, extracellular fluid by NaBr, intracellular fluid by calculation, plasma volume by CO rebreathe, interstitial fluid by calculation); (2) forehead/eyelids, tibia, and calcaneus tissue thickness (by ultrasound); (3) vascular dimensions by ultrasound (jugular veins, cerebral and carotid arteries, vertebral arteries and veins, portal vein); (4) vascular dynamics by MRI (head/neck blood flow, cerebrospinal fluid

  2. Local Directional Ternary Pattern for Facial Expression Recognition.

    Science.gov (United States)

    Ryu, Byungyong; Rivera, Adin Ramirez; Kim, Jaemyun; Chae, Oksam

    2017-07-11

    This paper presents a new face descriptor, local directional ternary pattern (LDTP), for facial expression recognition. LDTP efficiently encodes information of emotion-related features (i.e., eyes, eyebrows, upper nose, and mouth) by using the directional information and ternary pattern in order to take advantage of the robustness of edge patterns in the edge region while overcoming weaknesses of edge-based methods in smooth regions. Our proposal, unlike existing histogram-based face description methods that divide the face into several regions and sample the codes uniformly, uses a two level grid to construct the face descriptor while sampling expression-related information at different scales. We use a coarse grid for stable codes (highly related to non-expression), and a finer one for active codes (highly related to expression). This multi-level approach enables us to do a finer grain description of facial motions, while still characterizing the coarse features of the expression. Moreover, we learn the active LDTP codes from the emotionrelated facial regions. We tested our method by using persondependent and independent cross-validation schemes to evaluate the performance. We show that our approaches improve the overall accuracy of facial expression recognition on six datasets.

  3. Genetic Synthesis of New Reversible/Quantum Ternary Comparator

    Directory of Open Access Journals (Sweden)

    DEIBUK, V.

    2015-08-01

    Full Text Available Methods of quantum/reversible logic synthesis are based on the use of the binary nature of quantum computing. However, multiple-valued logic is a promising choice for future quantum computer technology due to a number of advantages over binary circuits. In this paper we have developed a synthesis of ternary reversible circuits based on Muthukrishnan-Stroud gates using a genetic algorithm. The method of coding chromosome is presented, and well-grounded choice of algorithm parameters allowed obtaining better circuit schemes of one- and n-qutrit ternary comparators compared with other methods. These parameters are quantum cost of received reversible devices, delay time and number of constant input (ancilla lines. Proposed implementation of the genetic algorithm has led to reducing of the device delay time and the number of ancilla qutrits to 1 and 2n-1 for one- and n-qutrits full comparators, respectively. For designing of n-qutrit comparator we have introduced a complementary device which compares output functions of 1-qutrit comparators.

  4. Enhanced Light Absorption in Fluorinated Ternary Small-Molecule Photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Eastham, Nicholas D. [Department; Dudnik, Alexander S. [Department; Harutyunyan, Boris [Department; Aldrich, Thomas J. [Department; Leonardi, Matthew J. [Department; Manley, Eric F. [Department; Chemical; Butler, Melanie R. [Department; Harschneck, Tobias [Department; Ratner, Mark A. [Department; Chen, Lin X. [Department; Chemical; Bedzyk, Michael J. [Department; Department; Melkonyan, Ferdinand S. [Department; Facchetti, Antonio [Department; Chang, Robert P. H. [Department; Marks, Tobin J. [Department; Department

    2017-06-14

    Using small-molecule donor (SMD) semiconductors in organic photovoltaics (OPVs) has historically afforded lower power conversion efficiencies (PCEs) than their polymeric counterparts. The PCE difference is attributed to shorter conjugated backbones, resulting in reduced intermolecular interactions. Here, a new pair of SMDs is synthesized based on the diketopyrrolopyrrole-benzodithiophene-diketopyrrolopyrrole (BDT-DPP2) skeleton but having fluorinated and fluorinefree aromatic side-chain substituents. Ternary OPVs having varied ratios of the two SMDs with PC61BM as the acceptor exhibit tunable open-circuit voltages (Vocs) between 0.833 and 0.944 V due to a fluorination-induced shift in energy levels and the electronic “alloy” formed from the miscibility of the two SMDs. A 15% increase in PCE is observed at the optimal ternary SMD ratio, with the short-circuit current density (Jsc) significantly increased to 9.18 mA/cm2. The origin of Jsc enhancement is analyzed via charge generation, transport, and diffuse reflectance measurements, and is attributed to increased optical absorption arising from a maximum in film crystallinity at this SMD ratio, observed by grazing incidence wide-angle X-ray scattering.

  5. HPMA-based block copolymers promote differential drug delivery kinetics for hydrophobic and amphiphilic molecules.

    Science.gov (United States)

    Tomcin, Stephanie; Kelsch, Annette; Staff, Roland H; Landfester, Katharina; Zentel, Rudolf; Mailänder, Volker

    2016-04-15

    We describe a method how polymeric nanoparticles stabilized with (2-hydroxypropyl)methacrylamide (HPMA)-based block copolymers are used as drug delivery systems for a fast release of hydrophobic and a controlled release of an amphiphilic molecule. The versatile method of the miniemulsion solvent-evaporation technique was used to prepare polystyrene (PS) as well as poly-d/l-lactide (PDLLA) nanoparticles. Covalently bound or physically adsorbed fluorescent dyes labeled the particles' core and their block copolymer corona. Confocal laser scanning microscopy (CLSM) in combination with flow cytometry measurements were applied to demonstrate the burst release of a fluorescent hydrophobic drug model without the necessity of nanoparticle uptake. In addition, CLSM studies and quantitative calculations using the image processing program Volocity® show the intracellular detachment of the amphiphilic block copolymer from the particles' core after uptake. Our findings offer the possibility to combine the advantages of a fast release for hydrophobic and a controlled release for an amphiphilic molecule therefore pointing to the possibility to a 'multi-step and multi-site' targeting by one nanocarrier. We describe thoroughly how different components of a nanocarrier end up in cells. This enables different cargos of a nanocarrier having a consecutive release and delivery of distinct components. Most interestingly we demonstrate individual kinetics of distinct components of such a system: first the release of a fluorescent hydrophobic drug model at contact with the cell membrane without the necessity of nanoparticle uptake. Secondly, the intracellular detachment of the amphiphilic block copolymer from the particles' core after uptake occurs. This offers the possibility to combine the advantages of a fast release for a hydrophobic substance at the time of interaction of the nanoparticle with the cell surface and a controlled release for an amphiphilic molecule later on therefore

  6. Fluid Fascinations

    NARCIS (Netherlands)

    Bokhove, Onno; Zwart, Valerie; Haveman, Martha J.

    De Art & Science show “Fluid Fascinations��? omvat een presentatie over de wetenschappelijke context, inclusief een live experiment (ontworpen samen met kunstenaar/designer Wout Zweers); en, gemengde media en olieverfschilderijen, en digitale fotowerken van kunstenares Valerie Zwart. De show is

  7. Evaluation of ternary blended cements for use in transportation concrete structures

    Science.gov (United States)

    Gilliland, Amanda Louise

    This thesis investigates the use of ternary blended cement concrete mixtures for transportation structures. The study documents technical properties of three concrete mixtures used in federally funded transportation projects in Utah, Kansas, and Michigan that used ternary blended cement concrete mixtures. Data were also collected from laboratory trial batches of ternary blended cement concrete mixtures with mixture designs similar to those of the field projects. The study presents the technical, economic, and environmental advantages of ternary blended cement mixtures. Different barriers of implementation for using ternary blended cement concrete mixtures in transportation projects are addressed. It was concluded that there are no technical, economic, or environmental barriers that exist when using most ternary blended cement concrete mixtures. The technical performance of the ternary blended concrete mixtures that were studied was always better than ordinary portland cement concrete mixtures. The ternary blended cements showed increased durability against chloride ion penetration, alkali silica reaction, and reaction to sulfates. These blends also had less linear shrinkage than ordinary portland cement concrete and met all strength requirements. The increased durability would likely reduce life cycle costs associated with concrete pavement and concrete bridge decks. The initial cost of ternary mixtures can be higher or lower than ordinary portland cement, depending on the supplementary cementitious materials used. Ternary blended cement concrete mixtures produce less carbon dioxide emissions than ordinary portland cement mixtures. This reduces the carbon footprint of construction projects. The barriers associated with implementing ternary blended cement concrete for transportation projects are not significant. Supplying fly ash returns any investment costs for the ready mix plant, including silos and other associated equipment. State specifications can make

  8. The structure and properties of a simple model mixture of amphiphilic molecules and ions at a solid surface

    Energy Technology Data Exchange (ETDEWEB)

    Pizio, O., E-mail: pizio@unam.mx [Instituto de Química, Universidad Nacional Autonoma de México, Circuito Exterior, Ciudad Universitaria, 04510 México, D.F. (Mexico); Sokołowski, S., E-mail: stefan.sokolowski@gmail.com [Department for the Modeling of Physico-Chemical Processes, Maria Curie-Skłodowska University, 20-031 Lublin (Poland); Sokołowska, Z. [Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin (Poland)

    2014-05-07

    We investigate microscopic structure, adsorption, and electric properties of a mixture that consists of amphiphilic molecules and charged hard spheres in contact with uncharged or charged solid surfaces. The amphiphilic molecules are modeled as spheres composed of attractive and repulsive parts. The electrolyte component of the mixture is considered in the framework of the restricted primitive model (RPM). The system is studied using a density functional theory that combines fundamental measure theory for hard sphere mixtures, weighted density approach for inhomogeneous charged hard spheres, and a mean-field approximation to describe anisotropic interactions. Our principal focus is in exploring the effects brought by the presence of ions on the distribution of amphiphilic particles at the wall, as well as the effects of amphiphilic molecules on the electric double layer formed at solid surface. In particular, we have found that under certain thermodynamic conditions a long-range translational and orientational order can develop. The presence of amphiphiles produces changes of the shape of the differential capacitance from symmetric or non-symmetric bell-like to camel-like. Moreover, for some systems the value of the potential of the zero charge is non-zero, in contrast to the RPM at a charged surface.

  9. ABC triblock surface active block copolymer with grafted ethoxylated fluoroalkyl amphiphilic side chains for marine antifouling/fouling-release applications.

    Science.gov (United States)

    Weinman, Craig J; Finlay, John A; Park, Daewon; Paik, Marvin Y; Krishnan, Sitaraman; Sundaram, Harihara S; Dimitriou, Michael; Sohn, Karen E; Callow, Maureen E; Callow, James A; Handlin, Dale L; Willis, Carl L; Kramer, Edward J; Ober, Christopher K

    2009-10-20

    An amphiphilic triblock surface-active block copolymer (SABC) possessing ethoxylated fluoroalkyl side chains was synthesized through the chemical modification of a polystyrene-block-poly(ethylene-ran-butylene)-block-polyisoprene polymer precursor. Bilayer coatings on glass slides consisting of a thin layer of the amphiphilic SABC spray coated on a thick layer of a polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) thermoplastic elastomer were prepared for biofouling assays with the green alga Ulva and the diatom Navicula. Dynamic water contact angle analysis and X-ray photoelectron spectroscopy (XPS) were used to characterize the surfaces. Additionally, the effect of the Young's modulus of the coating on the release properties of sporelings (young plants) of the green alga Ulva was examined through the use of two different SEBS thermoplastic elastomers possessing modulus values of an order of magnitude in difference. The amphiphilic SABC was found to reduce the settlement density of zoospores of Ulva as well as the strength of attachment of sporelings. The attachment strength of the sporelings was further reduced for the amphiphilic SABC on the "low"-modulus SEBS base layer. The weaker adhesion of diatoms, relative to a PDMS standard, further highlights the antifouling potential of this amphiphilic triblock hybrid copolymer.

  10. Fluid Mechanics

    Science.gov (United States)

    Pnueli, David; Gutfinger, Chaim

    1997-01-01

    This text is intended for the study of fluid mechanics at an intermediate level. The presentation starts with basic concepts, in order to form a sound conceptual structure that can support engineering applications and encourage further learning. The presentation is exact, incorporating both the mathematics involved and the physics needed to understand the various phenomena in fluid mechanics. Where a didactical choice must be made between the two, the physics prevails. Throughout the book the authors have tried to reach a balance between exact presentation, intuitive grasp of new ideas, and creative applications of concepts. This approach is reflected in the examples presented in the text and in the exercises given at the end of each chapter. Subjects treated are hydrostatics, viscous flow, similitude and order of magnitude, creeping flow, potential flow, boundary layer flow, turbulent flow, compressible flow, and non-Newtonian flows. This book is ideal for advanced undergraduate students in mechanical, chemical, aerospace, and civil engineering. Solutions manual available.

  11. A theoretical study of ternary indole-cation-anion complexes.

    Science.gov (United States)

    Carrazana-García, Jorge A; Cabaleiro-Lago, Enrique M; Campo-Cacharrón, Alba; Rodríguez-Otero, Jesús

    2014-12-07

    The simultaneous interactions of an anion and a cation with a π system were investigated by MP2 and M06-2X theoretical calculations. Indole was chosen as a model π system for its relevance in biological environments. Two different orientations of the anion, interacting with the N-H and with the C-H groups of indole, were considered. The four cations (Na(+), NH4(+), C(NH2)3(+) and N(CH3)4(+)) and the four anions (Cl(-), NO3(-), HCOO(-) and BF4(-)) included in the study are of biological interest. The total interaction energy of the ternary complexes was calculated and separated into its two- and three-body components and all of them are further divided into their electrostatic, exchange, repulsion, polarization and dispersion contributions using the local molecular orbital-energy decomposition analysis (LMO-EDA) methodology. The binding energy of the indole-cation-anion complexes depends on both ions, with the cation having the strongest effect. The intense cation-anion attraction determines the geometric and energetic features in all ternary complexes. These structures, with both ions on the same side of the π system, show an anti-cooperative interaction. However, the interaction is not only determined by electrostatics, but also the polarization contribution is important. Specific interactions like the one established between the anion and the N-H group of indole or the proton transfer between an acidic cation and a basic anion play a significant role in the energetics and the structure of particular complexes. The presence of the polar solvent as modelled with the polarizable continuum model (PCM) does not seem to have a significant effect on the geometry of the ternary complexes, but drastically weakens the interaction energy. Also, the strength of the interaction is reduced at a faster rate when the anion is pushed away, compared to the results obtained in the gas phase. The combination of PCM with the addition of one water molecule indicates that the PCM

  12. Fluid dynamics

    CERN Document Server

    Ruban, Anatoly I

    This is the first book in a four-part series designed to give a comprehensive and coherent description of Fluid Dynamics, starting with chapters on classical theory suitable for an introductory undergraduate lecture course, and then progressing through more advanced material up to the level of modern research in the field. The present Part 1 consists of four chapters. Chapter 1 begins with a discussion of Continuum Hypothesis, which is followed by an introduction to macroscopic functions, the velocity vector, pressure, density, and enthalpy. We then analyse the forces acting inside a fluid, and deduce the Navier-Stokes equations for incompressible and compressible fluids in Cartesian and curvilinear coordinates. In Chapter 2 we study the properties of a number of flows that are presented by the so-called exact solutions of the Navier-Stokes equations, including the Couette flow between two parallel plates, Hagen-Poiseuille flow through a pipe, and Karman flow above an infinite rotating disk. Chapter 3 is d...

  13. Multi-modal fission in collinear ternary cluster decay of 252Cf(sf, fff

    Directory of Open Access Journals (Sweden)

    W. von Oertzen

    2015-06-01

    Full Text Available We discuss the multiple decay modes of collinear fission in 252Cf(sf, fff, with three fragments as suggested by the potential energy surface (PES. Fission as a statistical decay is governed by the phase space of the different decay channels, which are suggested in the PES-landscape. The population of the fission modes is determined by the minima in the PES at the scission points and on the internal potential barriers. The ternary collinear decay proceeds as a sequential process, in two steps. The originally observed ternary decay of 252Cf(sf into three different masses (e.g. 132–140Sn, 52–48Ca, 68–72Ni, observed by the FOBOS group in the FLNR (Flerov Laboratory for Nuclear Reactions of the JINR (Dubna the collinear cluster tripartition (CCT, is one of the ternary fission modes. This kind of “true ternary fission” of heavy nuclei has often been predicted in theoretical works during the last decades. In the present note we discuss different ternary fission modes in the same system. The PES shows pronounced minima, which correspond to several modes of ternary fragmentations. These decays have very similar dynamical features as the previously observed CCT-decays. The data obtained in the experiments on CCT allow us to extract the yields for different decay modes using specific gates on the measured parameters, and to establish multiple modes of the ternary fission decay.

  14. He and Be ternary spontaneous fission of sup 2 sup 5 sup 2 Cf

    CERN Document Server

    Hwang, J K; Ramayya, A V; Hamilton, J H

    2002-01-01

    Ternary and binary fission studies of sup 2 sup 5 sup 2 Cf have been carried out by using the Gammasphere detector array with light charged particle (LCD) detectors. The relative sup 4 He and sup 5 He ternary fission yields were determined. The kinetic energies of the sup 5 He and sup 4 He ternary particles were found to be approximately 11 and 16 MeV, respectively. The sup 5 He particles contribute 10-20 % to the total observed alpha ternary yield. The data indicate that in nuclei with octupole deformations the population for the negative parity bands might be enhanced in the alpha ternary fission. >From LCP-gamma double gated spectra, neutron multiplicity distributions for alpha ternary fission pairs were measured. The average neutron multiplicity decreases about 0.7 AMU in going from the binary to alpha ternary fission in the approximately same mass splittings (104-146). From the analysis of the gamma-gamma matrix gated on the sup 1 sup 0 Be particles, the two fragment pairs of sup 1 sup 3 sup 8 Xe - sup 1...

  15. Core–Shell Structure and Aggregation Number of Micelles Composed of Amphiphilic Block Copolymers and Amphiphilic Heterografted Polymer Brushes Determined by Small-Angle X-ray Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Szymusiak, Magdalena [Department; Kalkowski, Joseph [Department; Luo, Hanying [Department; Donovan, Alexander J. [Department; Zhang, Pin [Department; Liu, Chang [Department; Shang, Weifeng [Department; Irving, Thomas [Department; Herrera-Alonso, Margarita [Department; Liu, Ying [Department; Department

    2017-08-16

    A large group of functional nanomaterials employed in biomedical applications, including targeted drug delivery, relies on amphiphilic polymers to encapsulate therapeutic payloads via self-assembly processes. Knowledge of the micelle structures will provide critical insights into design of polymeric drug delivery systems. Core–shell micelles composed of linear diblock copolymers poly(ethylene glycol)-b-poly(caprolactone) (PEG-b-PCL), poly(ethylene oxide)-b-poly(lactic acid) (PEG-b-PLA), as well as a heterografted brush consisting of a poly(glycidyl methacrylate) backbone with PEG and PLA branches (PGMA-g-PEG/PLA) were characterized by dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS) measurements to gain structural information regarding the particle morphology, core–shell size, and aggregation number. The structural information at this quasi-equilibrium state can also be used as a reference when studying the kinetics of polymer micellization.

  16. Core–Shell Structure and Aggregation Number of Micelles Composed of Amphiphilic Block Copolymers and Amphiphilic Heterografted Polymer Brushes Determined by Small-Angle X-ray Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Szymusiak, Magdalena; Kalkowski, Joseph; Luo, Hanying; Donovan, Alexander J.; Zhang, Pin; Liu, Chang; Shang, Weifeng; Irving, Thomas; Herrera-Alonso, Margarita; Liu, Ying (JHU); (IIT); (UIC)

    2017-08-31

    A large group of functional nanomaterials employed in biomedical applications, including targeted drug delivery, relies on amphiphilic polymers to encapsulate therapeutic payloads via self-assembly processes. Knowledge of the micelle structures will provide critical insights into design of polymeric drug delivery systems. Core–shell micelles composed of linear diblock copolymers poly(ethylene glycol)-b-poly(caprolactone) (PEG-b-PCL), poly(ethylene oxide)-b-poly(lactic acid) (PEG-b-PLA), as well as a heterografted brush consisting of a poly(glycidyl methacrylate) backbone with PEG and PLA branches (PGMA-g-PEG/PLA) were characterized by dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS) measurements to gain structural information regarding the particle morphology, core–shell size, and aggregation number. The structural information at this quasi-equilibrium state can also be used as a reference when studying the kinetics of polymer micellization.

  17. Construction of amphiphilic segments on polypropylene nonwoven surface and its application in removal of endocrine disrupting compounds (EDCs) from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Kai [State Key Laboratory of Hollow Fiber Membrane Materials and Processes, Tianjin Polytechnic University, Tianjin 300160 (China); School of Environmental and Chemical Engineering, Tianjin Polytechnic University, Tianjin 300160 (China); Wei, Junfu, E-mail: junfuwei1963@163.com [State Key Laboratory of Hollow Fiber Membrane Materials and Processes, Tianjin Polytechnic University, Tianjin 300160 (China); School of Environmental and Chemical Engineering, Tianjin Polytechnic University, Tianjin 300160 (China); Zhou, Xiangyu [State Key Laboratory of Hollow Fiber Membrane Materials and Processes, Tianjin Polytechnic University, Tianjin 300160 (China); School of Environmental and Chemical Engineering, Tianjin Polytechnic University, Tianjin 300160 (China); School of Materials Science and Engineering, Tianjin Polytechnic University, Tianjin 300160 (China); Liu, Nana [State Key Laboratory of Hollow Fiber Membrane Materials and Processes, Tianjin Polytechnic University, Tianjin 300160 (China); School of Environmental and Chemical Engineering, Tianjin Polytechnic University, Tianjin 300160 (China)

    2015-05-15

    Highlights: • The amphiphilic segments on polypropylene nonwoven surface were constructed successfully. • The adsorption behavior for EDCs of the amphiphilic adsorption materials was systematically studied. • The novel amphiphilic adsorption materials have broad application prospects in EDCs removal from aqueous solution. - Abstract: The amphiphilic segments on polypropylene nonwoven (PP nonwoven) surface were constructed using the ultraviolet (UV) irradiation graft polymerization for the removal of endocrine disrupting compounds (EDCs) with different polarity from aqueous solution. The stearyl acrylate (SA) as hydrophobic functional monomer was introduced onto the surface of PP nonwoven fabric at first stage and then the hydroxyethyl acrylate (HEA) as hydrophilic functional monomer was introduced subsequently. The effect of functional monomer concentration and UV irradiation time on grafting ratio was studied and discussed. The novel amphiphilic structure was designed and constructed based on adsorption capacity for the target micropollutants. The structure and composition of the amphiphilic adsorption materials were characterized by Fourier transform infrared spectrometer (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and contact angle (CA). The adsorption behaviors for EDCs of the amphiphilic adsorption materials were studied and the results indicated that the adsorption capacity and adsorption rate were superior to single SA grafted PP nonwoven (PP-g-SA) and single HEA grafted PP nonwoven (PP-g-HEA). The novel amphiphilic adsorption material was efficient for the removal of EDCs with different polarity and could be utilized as a potential adsorption material for removing EDCs from aqueous solution.

  18. Hardware emulation of Memristor based Ternary Content Addressable Memory

    KAUST Repository

    Bahloul, Mohamed A.

    2017-12-13

    MTCAM (Memristor Ternary Content Addressable Memory) is a special purpose storage medium in which data could be retrieved based on the stored content. Using Memristors as the main storage element provides the potential of achieving higher density and more efficient solutions than conventional methods. A key missing item in the validation of such approaches is the wide spread availability of hardware emulation platforms that can provide reliable and repeatable performance statistics. In this paper, we present a hardware MTCAM emulation based on 2-Transistors-2Memristors (2T2M) bit-cell. It builds on a bipolar memristor model with storing and fetching capabilities based on the actual current-voltage behaviour. The proposed design offers a flexible verification environment with quick design revisions, high execution speeds and powerful debugging techniques. The proposed design is modeled using VHDL and prototyped on Xilinx Virtex® FPGA.

  19. Normal freezing of ideal ternary systems of the pseudobinary type

    Science.gov (United States)

    Li, C. H.

    1972-01-01

    Perfect liquid mixing but no solid diffusion is assumed in normal freezing. In addition, the molar compositions of the freezing solid and remaining liquid, respectively, follow the solidus and liquidus curves of the constitutional diagram. For the linear case, in which both the liquidus and solidus are perfectly straight lines, the normal freezing equation giving the fraction solidified at each melt temperature and the solute concentration profile in the frozen solid was determined as early as 1902, and has since been repeatedly published. Corresponding equations for quadratic, cubic or higher-degree liquidus and solidus lines have also been obtained. The equation of normal freezing for ideal ternary liquid solutions solidified into ideal solid solutions of the pseudobinary type is given. Sample computations with the use of this new equation were made and are given for the Ga-Al-As system.

  20. Nonequilibrium patterns in phase-separating ternary membranes

    Science.gov (United States)

    Gómez, Jordi; Sagués, Francesc; Reigada, Ramon

    2009-07-01

    We present a nonequilibrium approach for the study of a two-dimensional phase-separating ternary mixture. When the component that promotes phase separation is dynamically exchanged with the medium, the separation process is halted and actively maintained finite-size segregation domains appear in the system. In addition to this effect, already reported in our earlier work [J. Gómez, F. Sagués, and R. Reigada, Phys. Rev. E 77, 021907 (2008)], the use of a generic Ginzburg-Landau formalism and the inclusion of thermal fluctuations provide a more dynamic description of the resulting domain organization. Its size, shape, and stability properties are studied. Larger and more circular and stable domains are formed when decreasing the recycling rate, increasing the mobility of the exchanged component, and the mixture is quenched deeper. We expect this outcome to be of applicability in raft phenomenology in plasmatic cell membranes.

  1. A high-throughput search for new ternary superalloys

    Science.gov (United States)

    Nyshadham, Chandramouli; Hansen, Jacob; Oses, Corey; Curtarolo, Stefano; Hart, Gus

    In 2006 an unexpected new superalloy, Co3[Al,W], was discovered. This new alloy is cobalt-based, in contrast to conventional superalloys, which are nickel-based. Inspired by this new discovery, we performed first-principles calculations, searching through 2224 ternary metallic systems of the form A3[B0.5C0.5], where A = Ni/Co/Fe and [B, C] = all binary combinations of 40 different elements chosen from the periodic table. We found 175 new systems that are better than the Co3[Al, W] superalloy. 75 of these systems are brand new--they have never been reported in experimental literature. These 75 new potential superalloys are good candidates for further experiments. Our calculations are consistent with current experimental literature where data exists. Work supported under: ONR (MURI N00014-13-1-0635).

  2. Hardness and Microstructure of Binary and Ternary Nitinol Compounds

    Science.gov (United States)

    Stanford, Malcolm K.

    2016-01-01

    The hardness and microstructure of twenty-six binary and ternary Nitinol (nickel titanium, nickel titanium hafnium, nickel titanium zirconium and nickel titanium tantalum) compounds were studied. A small (50g) ingot of each compound was produced by vacuum arc remelting. Each ingot was homogenized in vacuum for 48 hr followed by furnace cooling. Specimens from the ingots were then heat treated at 800, 900, 1000 or 1100 degree C for 2 hr followed by water quenching. The hardness and microstructure of each specimen was compared to the baseline material (55-Nitinol, 55 at.% nickel - 45 at.% titanium, after heat treatment at 900 degC). The results show that eleven of the studied compounds had higher hardness values than the baseline material. Moreover, twelve of the studied compounds had measured hardness values greater 600HV at heat treatments from 800 to 900 degree C.

  3. Comprehensive characterization of chitosan/PEO/levan ternary blend films.

    Science.gov (United States)

    Bostan, Muge Sennaroglu; Mutlu, Esra Cansever; Kazak, Hande; Sinan Keskin, S; Oner, Ebru Toksoy; Eroglu, Mehmet S

    2014-02-15

    Ternary blend films of chitosan, PEO (300,000) and levan were prepared by solution casting method and their phase behavior, miscibility, thermal and mechanical properties as well as their surface energy and morphology were characterized by different techniques. FT-IR analyses of blend films indicated intermolecular hydrogen bonding between blend components. Thermal and XRD analysis showed that chitosan and levan suppressed the crystallinity of PEO up to nearly 25% of PEO content in the blend, which resulted in more amorphous film structures at higher PEO/(chitosan+levan) ratios. At more than 30% of PEO concentration, contact angle (CA) measurements showed a surface enrichment of PEO whereas at lower PEO concentrations, chitosan and levan were enriched on the surfaces leading to more amorphous and homogenous surfaces. This result was further confirmed by atomic force microscopy (AFM) images. Cell proliferation and viability assay established the high biocompatibility of the blend films. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Designing and analysing parallel control for multifeed ternary systems

    Directory of Open Access Journals (Sweden)

    Rocío Solar-González

    2010-06-01

    Full Text Available This paper explores a parallel control structure for improving the behaviour of a chemical plant having recycling and multi- ple feed streams; a ternary system is taken as an example,having an A + B → C second-order irreversible reaction. Material recycling dynamics can induce the so-called snowball effect in the presence of disturbance in the feed stream. The snowball effect can be prevented by distributing load through the parallel control scheme. A control structure was thus pro- posed where product composition was regulated by means of simultaneous feedback manipulation of final column vapour boilup rate and reactor temperature. An extension was made for one reactor, one distillation column and recycle stream configuration. Nonlinear simulations showed that effective composition control could be obtained with moderate vapour boilup control efforts.

  5. Morphological Control Agent in Ternary Blend Bulk Heterojunction Solar Cells

    Directory of Open Access Journals (Sweden)

    Hsueh-Chung Liao

    2014-11-01

    Full Text Available Bulk heterojunction (BHJ organic photovoltaic (OPV promise low cost solar energy and have caused an explosive increase in investigations during the last decade. Control over the 3D morphology of BHJ blend films in various length scales is one of the pillars accounting for the significant advance of OPV performance recently. In this contribution, we focus on the strategy of incorporating an additive into BHJ blend films as a morphological control agent, i.e., ternary blend system. This strategy has shown to be effective in tailoring the morphology of BHJ through different inter- and intra-molecular interactions. We systematically review the morphological observations and associated mechanisms with respect to various kinds of additives, i.e., polymers, small molecules and inorganic nanoparticles. We organize the effects of morphological control (compatibilization, stabilization, etc. and provide general guidelines for rational molecular design for additives toward high efficiency and high stability organic solar cells.

  6. Ternary gypsum-based materials: Composition, properties and utilization

    Science.gov (United States)

    Doleželová, M.; Svora, P.; Vimmrová, A.

    2017-10-01

    In spite of the fact that gypsum is one of the most environmentally friendly binders, utilization of gypsum products is relatively narrow. The main problem of gypsum materials is their low resistance to the wet environment and radical decrease of mechanical properties with increasing moisture. The solution of the problem could be in use of composed gypsum-based binders, usually ternary, comprising gypsum, pozzolan and alkali activator of pozzolan reaction. These materials have a better moisture resistance and often also better mechanical properties. Paper provides literature survey of the possible compositions, properties and ways of utilization of the composed gypsum-based binders with latent hydraulic and pozzolan materials together with some results of present research performed by authors.

  7. Issues Affecting the Synthetic Scalability of Ternary Metal Ferrite Nanoparticles

    Directory of Open Access Journals (Sweden)

    Lauren Morrow

    2015-01-01

    Full Text Available Ternary Mn-Zn ferrite (MnxZn1-xFe2O4 nanoparticles (NPs have been prepared by the thermal decomposition of an oleate complex, sodium dodecylbenzenesulfonate (SDBS mediated hydrazine decomposition of the chloride salts, and triethylene glycol (TREG mediated thermal decomposition of the metal acetylacetonates. Only the first method was found to facilitate the synthesis of uniform, isolable NPs with the correct Mn : Zn ratio (0.7 : 0.3 as characterized by small angle X-ray scattering (SAXS, transmission electron microscopy (TEM, and inductively coupled plasma-optical emission spectroscopy (ICP-OES. Scaling allowed for retention of the composition and size; however, attempts to prepare Zn-rich ferrites did not result in NP formation. Thermogravimetric analysis (TGA indicated that the incomplete decomposition of the metal-oleate complexes prior to NP nucleation for Zn-rich compositions is the cause.

  8. Ternary cobalt-molybdenum-zirconium coatings for alternative energies

    Science.gov (United States)

    Yar-Mukhamedova, Gulmira; Ved', Maryna; Sakhnenko, Nikolay; Koziar, Maryna

    2017-11-01

    Consistent patterns for electrodeposition of Co-Mo-Zr coatings from polyligand citrate-pyrophosphate bath were investigated. The effect of both current density amplitude and pulse on/off time on the quality, composition and surface morphology of the galvanic alloys were determined. It was established the coating Co-Mo-Zr enrichment by molybdenum with current density increasing up to 8 A dm-2 as well as the rising of pulse time and pause duration promotes the content of molybdenum because of subsequent chemical reduction of its intermediate oxides by hydrogen ad-atoms. It was found that the content of the alloying metals in the coating Co-Mo-Zr depends on the current density and on/off times extremely and maximum Mo and Zr content corresponds to the current density interval 4-6 A dm-2, on-/off-time 2-10 ms. Chemical resistance of binary and ternary coatings based on cobalt is caused by the increased tendency to passivity and high resistance to pitting corrosion in the presence of molybdenum and zirconium, as well as the acid nature of their oxides. Binary coating with molybdenum content not less than 20 at.% and ternary ones with zirconium content in terms of corrosion deep index are in a group ;very proof;. It was shown that Co-Mo-Zr alloys exhibits the greatest level of catalytic properties as cathode material for hydrogen electrolytic production from acidic media which is not inferior a platinum electrode. The deposits Co-Mo-Zr with zirconium content 2-4 at.% demonstrate high catalytic properties in the carbon(II) oxide conversion. This confirms the efficiency of materials as catalysts for the gaseous wastes purification and gives the reason to recommend them as catalysts for red-ox processes activating by oxygen as well as electrode materials for red-ox batteries.

  9. Cohesion energy calculations for ternary ionic novel crystals

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez Polo, G; Valdes, E. [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico); Mijngos, R. R; Duarte, D. [Universidad de Sonora, Hermosillo, Sonora (Mexico)

    2001-12-01

    The present work calculates the value of the link energy of a crystalline ternary structure newly formed by alkali halides. The ternary structure prepared with different concentrations of KCI{sub x}KBr{sub y}RbCl{sub z} maintains a very good miscibility and stability. The calculation is based on the use of a generalization of the Vegard's law (which generally is valid for binary compounds) for calculating the values of the lattice constant and the repulsive m exponent. The values of the lattice parameter given X-ray diffractometry agrees with the close approximation of the calculated value of the method used. It also compares the value of energy cohesion obtained by the Born expression with more complex approximations. [Spanish] En el presente trabajo se calcula el valor de la energia de amarre de una estructura ternaria cristalina nueva formada por halogenuros alcalinos. La estructura ternaria preparada con diferentes concentraciones KCI{sub x}KBr{sub y}RbCl{sub z} mantiene una muy buena estabilidad y miscibilidad. El calculo se basa en el uso de una generalizacion de la ley de Vegard (que en general es valida para compuestos binarios) para calcular los valores de la constante de red y de exponente repulsivo m. El valor del parametro de red medido por difractometria de rayos X, concuerda en buena aproximacion con el valor calculado por el metodo usado. Tambien se compara el valor de la energia de cohesion obtenido por la expresion de Born con aproximaciones mas complejas.

  10. Boron-Based Hydrogen Storage: Ternary Borides and Beyond

    Energy Technology Data Exchange (ETDEWEB)

    Vajo, John J. [HRL Laboratories, LLC, Malibu, CA (United States)

    2016-04-28

    DOE continues to seek reversible solid-state hydrogen materials with hydrogen densities of ≥11 wt% and ≥80 g/L that can deliver hydrogen and be recharged at moderate temperatures (≤100 °C) and pressures (≤100 bar) enabling incorporation into hydrogen storage systems suitable for transportation applications. Boron-based hydrogen storage materials have the potential to meet the density requirements given boron’s low atomic weight, high chemical valance, and versatile chemistry. However, the rates of hydrogen exchange in boron-based compounds are thus far much too slow for practical applications. Although contributing to the high hydrogen densities, the high valance of boron also leads to slow rates of hydrogen exchange due to extensive boron-boron atom rearrangements during hydrogen cycling. This rearrangement often leads to multiple solid phases occurring over hydrogen release and recharge cycles. These phases must nucleate and react with each other across solid-solid phase boundaries leading to energy barriers that slow the rates of hydrogen exchange. This project sought to overcome the slow rates of hydrogen exchange in boron-based hydrogen storage materials by minimizing the number of solid phases and the boron atom rearrangement over a hydrogen release and recharge cycle. Two novel approaches were explored: 1) developing matched pairs of ternary borides and mixed-metal borohydrides that could exchange hydrogen with only one hydrogenated phase (the mixed-metal borohydride) and only one dehydrogenated phase (the ternary boride); and 2) developing boranes that could release hydrogen by being lithiated using lithium hydride with no boron-boron atom rearrangement.

  11. Luminescent supramolecular soft nanostructures from amphiphilic dinuclear Re(i) complexes

    Science.gov (United States)

    Cebrián, Cristina; Natali, Mirco; Villa, Davide; Panigati, Monica; Mauro, Matteo; D'Alfonso, Giuseppe; de Cola, Luisa

    2015-07-01

    Luminescent metallo-surfactants based on highly emissive dinuclear Re(i) complexes have been synthesized combining the peculiar photophysical behaviour of this class of neutral hydrophobic complexes with new properties imparted by hydrophilic chains anchored on the coordinated chromophoric ligand. In solution, the resulting neutral amphiphiles tend to self-assembly in soft structures. The aggregation properties have been thoroughly investigated in dioxane-water mixtures, where all the complexes assembly in globular-like supramolecular architectures with well-defined size (hydrodynamic diameter = 200-400 nm). The morphology of these nano-objects has been completely characterized with Dynamic Light Scattering (DLS) analysis, Scanning Transmission Electron Microscopy (STEM) and cryo-TEM to determine the size, polydispersity, and stability of the nanoparticles in relationship with the structure of the metallo-surfactants. The photophysical properties of both the isolated metal complexes and their aggregates have been investigated by means of UV-Vis absorption, steady-state and time-resolved emission spectroscopy. Noteworthy, the self-assembly properties of the reported luminescent rhenium metallo-amphiphiles can be modulated by solvent polarity. Even more importantly, such aggregation process yielded a small hypsochromic shift of the emission energy accompanied by a sizeable elongation of the excited-state lifetime and an enhancement of the photoluminescence quantum yield, reaching a remarkably high value of 0.20 despite the air-equilibrated aqueous condition. The presented findings endorse novel possibilities for the efficient use of soft-nanostructures based on metallo-amphiphiles in dual (electron and optical microscopy) bio-imaging applications and theranostics where the non-covalent nature of the intermolecular interactions would offer the powerful and unique possibility to reversibly assemble and disassemble imaging agents.Luminescent metallo-surfactants based on

  12. Self-assembly behavior of a linear-star supramolecular amphiphile based on host-guest complexation.

    Science.gov (United States)

    Wang, Juan; Wang, Xing; Yang, Fei; Shen, Hong; You, Yezi; Wu, Decheng

    2014-11-04

    A star polymer, β-cyclodextrin-poly(l-lactide) (β-CD-PLLA), and a linear polymer, azobenzene-poly(ethylene glycol) (Azo-PEG), could self-assemble into a supramolecular amphiphilic copolymer (β-CD-PLLA@Azo-PEG) based on the host-guest interaction between β-CD and azobenzene moieties. This linear-star supramolecular amphiphilic copolymer further self-assembled into a variety of morphologies, including sphere-like micelle, carambola-like micelle, naan-like micelle, shuttle-like lamellae, tube-like fiber, and random curled-up lamellae, by tuning the length of hydrophilic or hydrophobic chains. The variation of morphology was closely related to the topological structure and block ratio of the supramolecular amphiphiles. These self-assembly structures could disassemble upon an ultraviolet (UV) light irradiation.

  13. Membrane Insertion for the Detection of Lipopolysaccharides: Exploring the Dynamics of Amphiphile-in-Lipid Assays.

    Directory of Open Access Journals (Sweden)

    Loreen R Stromberg

    Full Text Available Shiga toxin-producing Escherichia coli is an important cause of foodborne illness, with cases attributable to beef, fresh produce and other sources. Many serotypes of the pathogen cause disease, and differentiating one serotype from another requires specific identification of the O antigen located on the lipopolysaccharide (LPS molecule. The amphiphilic structure of LPS poses a challenge when using classical detection methods, which do not take into account its lipoglycan biochemistry. Typically, detection of LPS requires heat or chemical treatment of samples and relies on bioactivity assays for the conserved lipid A portion of the molecule. Our goal was to develop assays to facilitate the direct and discriminative detection of the entire LPS molecule and its O antigen in complex matrices using minimal sample processing. To perform serogroup identification of LPS, we used a method called membrane insertion on a waveguide biosensor, and tested three serogroups of LPS. The membrane insertion technique allows for the hydrophobic association of LPS with a lipid bilayer, where the exposed O antigen can be targeted for specific detection. Samples of beef lysate were spiked with LPS to perform O antigen specific detection of LPS from E. coli O157. To validate assay performance, we evaluated the biophysical interactions of LPS with lipid bilayers both in- and outside of a flow cell using fluorescence microscopy and fluorescently doped lipids. Our results indicate that membrane insertion allows for the qualitative and reliable identification of amphiphilic LPS in complex samples like beef homogenates. We also demonstrated that LPS-induced hole formation does not occur under the conditions of the membrane insertion assays. Together, these findings describe for the first time the serogroup-specific detection of amphiphilic LPS in complex samples using a membrane insertion assay, and highlight the importance of LPS molecular conformations in detection

  14. A Review of the Role of Amphiphiles in Biomass to Ethanol Conversion

    Directory of Open Access Journals (Sweden)

    William Gibbons

    2013-04-01

    Full Text Available One of the concerns for economical production of ethanol from biomass is the large volume and high cost of the cellulolytic enzymes used to convert biomass into fermentable sugars. The presence of acetyl groups in hemicellulose and lignin in plant cell walls reduces accessibility of biomass to the enzymes and makes conversion a slow process. In addition to low enzyme accessibility, a rapid deactivation of cellulases during biomass hydrolysis can be another factor contributing to the low sugar recovery. As of now, the economical reduction in lignin content of the biomass is considered a bottleneck, and raises issues for several reasons. The presence of lignin in biomass reduces the swelling of cellulose fibrils and accessibility of enzyme to carbohydrate polymers. It also causes an irreversible adsorption of the cellulolytic enzymes that prevents effective enzyme activity and recycling. Amphiphiles, such as surfactants and proteins have been found to improve enzyme activity by several mechanisms of action that are not yet fully understood. Reduction in irreversible adsorption of enzyme to non-specific sites, reduction in viscosity of liquid and surface tension and consequently reduced contact of enzyme with air-liquid interface, and modifications in biomass chemical structure are some of the benefits derived from surface active molecules. Application of some of these amphiphiles could potentially reduce the capital and operating costs of bioethanol production by reducing fermentation time and the amount of enzyme used for saccharification of biomass. In this review article, the benefit of applying amphiphiles at various stages of ethanol production (i.e., pretreatment, hydrolysis and hydrolysis-fermentation is reviewed and the proposed mechanisms of actions are described.

  15. Two-dimensional crystallography of amphiphilic molecules at the air-water interface

    DEFF Research Database (Denmark)

    Jacquemain, D.; Grayer Wolf, S.; Leveiller, F.

    1992-01-01

    time the determination of the in-plane and vertical structure of such monolayers with a resolution approaching the atomic level. We briefly describe these methods, including grazing incidence X-ray diffraction, specular reflectivity, Bragg rods, standing waves, and surface fluorescence techniques......, and review recent results obtained from them for Langmuir films. The methods have been successfully applied in the elucidation of the structure of crystalline aggregates of amphiphilic molecules such as alcohols, carboxylic acids and their salts, alpha-amino acids, and phospholipids at the water surface...

  16. Novel self-associative and multiphase nanostructured soft carriers based on amphiphilic hyaluronic acid derivatives

    DEFF Research Database (Denmark)

    Eenschooten, Corinne; Vaccaro, Andrea; Delie, Florence

    2012-01-01

    The purpose of the present study was to investigate the physicochemical properties in aqueous media of amphiphilic hyaluronic acid (HA) derivatives obtained by reaction of HA’s hydroxyl groups with octenyl succinic anhydride (OSA). The self-associative properties of the resulting octenyl succinic...... anhydridemodified hyaluronic acid (OSA-HA) derivatives were studied by fluorescence spectroscopy using Nile Red as fluorophore. The morphology, size and surface charge of the OSA-HA assemblies were determined by transmission electron microscopy, dynamic light scattering and by measuring their electrophoretic...

  17. Supramolecular helical nanofibers assembled from a pyridinium-functionalized methyl glycyrrhetate amphiphile

    Science.gov (United States)

    Gao, Yuxia; Hao, Jie; Wu, Jindan; Zhang, Xun; Hu, Jun; Ju, Yong

    2015-08-01

    A glycyrrhetate-containing amphiphile, MGP (1-[2-(methyl glycyrrhetate)-2-oxoethyl]pyridinium bromide), has been synthesized, and found to assemble into supramolecular helical nanofibers in chloroform/aromatic solvents, which are primarily driven by π-π stacking, van der Waals forces, and hydrophobic interactions. During the assembly process, MGP stacked into J-aggregates resulting in the sequestration of the hydrophilic pyridinium cation within the interior with the concomitant projection of its hydrophobic skeleton on the outside surface. Ultimately, this protrusion generated a staggered angle due to the steric hindrance between stacked molecules. This staggered angle further led to molecular misalignments and the formation of helical fibrils, which could twist with each other to fabricate larger helical fibers. Consequently, a gel was formed by intertwining these nanofibers into three-dimensional networks. Using this strategy, we found that other triterpenoid-tailored pyridinium amphiphiles are also potential scaffolds for supramolecular helical structures. This work provides a facile approach for the fabrication of supramolecular macroscopic chiral nanostructures that originate from natural products.A glycyrrhetate-containing amphiphile, MGP (1-[2-(methyl glycyrrhetate)-2-oxoethyl]pyridinium bromide), has been synthesized, and found to assemble into supramolecular helical nanofibers in chloroform/aromatic solvents, which are primarily driven by π-π stacking, van der Waals forces, and hydrophobic interactions. During the assembly process, MGP stacked into J-aggregates resulting in the sequestration of the hydrophilic pyridinium cation within the interior with the concomitant projection of its hydrophobic skeleton on the outside surface. Ultimately, this protrusion generated a staggered angle due to the steric hindrance between stacked molecules. This staggered angle further led to molecular misalignments and the formation of helical fibrils, which could

  18. Synthesis of Novel Amphiphilic Azobenzenes and X-ray Scattering Studies of Their Langmuir Monolayers

    DEFF Research Database (Denmark)

    Sørensen, Thomas Just; Kjær, Kristian; Breiby, Dag Werner

    2008-01-01

    . At the air-water interface, the amphiphilic azobenzenes form noncrystalline but stable Langmuir films that display an unusual reversible monolayer collapse close to 35 mN/m. The structures and phase transitions were studied by X-ray reflectivity (XR) and grazing-incidence X-ray diffraction, both utilizing...... synchrotron radiation. Compression beyond the collapse point does not change the XR data, showing that the film is unchanged at the molecular level, even at areas less than half of that of the collapse. This leads to the conclusion that few macroscopic collapse sites are responsible for reversibly removing...

  19. Characterization of micellar systems produced by new amphiphilic conjugates of poly(ethylene glycol).

    Science.gov (United States)

    Pignatello, R; Pantò, V; Basile, L; Leonardi, A; Guarino, C; La Rosa, C

    2014-11-01

    This study proposes polymeric micelles produced using new amphiphilic conjugates between amino- or carboxy-mPEG2000 and three different α-lipoamino acids (PEG-LAA). The characterization of these colloidal systems showed CMC values, in the order of 10(-5 )M, that are interesting in the view of an in vivo administration. The PEG-LAA micelles also showed a good stability at 37 °C and upon dilution in aqueous media. Using a colored probe as a model lipophilic compound, the loading efficiency and in vitro release profile were also outlined.

  20. Gold Nanoparticles Protected with Thiol-Derivatized Amphiphilic Poly(epsilon-caprolactone)-b-poly(acrylic acid)

    DEFF Research Database (Denmark)

    Javakhishvili, Irakli; Hvilsted, Søren

    2009-01-01

    Amphiphilic poly(epsilon-caprolactone)-b-poly(acrylic acid) (HS-PCL-b-PAA) with a thiol functionality in the PCL terminal has been prepared in a novel synthetic cascade. Initially, living anionic ring-opening polymerization (ROP) of epsilon-caprolactone (epsilon-CL) employing the difunctional......) of tent-butyl acrylate (tBA) in a controlled fashion by use of NiBr2(PPh3)(2) catalyst to produce Prot-PCL-b-PtBA with narrow polydispersities (1.17-1.39). Subsequent mild deprotection protocols provided HS-PCL-b-PAA. Reduction of a gold salt in the presence of this macroligand under thiol...

  1. Plasmonic Vesicles of Amphiphilic Nanocrystals: Optically Active Multifunctional Platform for Cancer Diagnosis and Therapy.

    Science.gov (United States)

    Song, Jibin; Huang, Peng; Duan, Hongwei; Chen, Xiaoyuan

    2015-09-15

    Vesicular structures with compartmentalized, water-filled cavities, such as liposomes of natural and synthetic amphiphiles, have tremendous potential applications in nanomedicine. When block copolymers self-assemble, the result is polymersomes with tailored structural properties and built-in releasing mechanisms, controlled by stimuli-responsive polymer building blocks. More recently, chemists are becoming interested in multifunctional hybrid vesicles containing inorganic nanocrystals with unique optical, electronic, and magnetic properties. In this Account, we review our recent progress in assembling amphiphilic plasmonic nanostructures to create a new class of multifunctional hybrid vesicles and applying them towards cancer diagnosis and therapy. Localized surface plasmon resonance (LSPR) gives plasmonic nanomaterials a unique set of optical properties that are potentially useful for both biosensing and nanomedicine. For instance, the strong light scattering at their LSPR wavelength opens up the applications of plasmonic nanostructures in single particle plasmonic imaging. Their superior photothermal conversion properties, on the other hand, make them excellent transducers for photothermal ablation and contrast agents for photoacoustic imaging. Of particular note for ultrasensitive detection is that the confined electromagnetic field resulting from excitation of LSPR can give rise to highly efficient surface enhanced Raman scattering (SERS) for molecules in close proximity. We have explored several ways to combine well-defined plasmonic nanocrystals with amphiphilic polymer brushes of diverse chemical functionalities. In multiple systems, we have shown that the polymer grafts impart amphiphilicity-driven self-assembly to the hybrid nanoparticles. This has allowed us to synthesize well-defined vesicles in which we have embedded plasmonic nanocrystals in the shell of collapsed hydrophobic polymers. The hydrophilic brushes extend into external and interior aqueous

  2. Synthesis, Characterization, and Aqueous Lubricating Properties of Amphiphilic Graft Copolymers Comprising 2-Methoxyethyl Acrylate

    DEFF Research Database (Denmark)

    Javakhishvili, Irakli; Røn, Troels; Jankova Atanasova, Katja

    2014-01-01

    of the corresponding monomers followed by deblocking reaction leads to well-defined amphiphiles with narrow molecular weight distributions (PDI ≤ 1.29) and varying content of methacrylic acid. The graft copolymers showed effective surface adsorption and lubrication for self-mated poly(dimethylsiloxane) (PDMS) contacts...... in physiological salt concentration. This is indebted from “dilution” of the charges along the grafted chains by balancing neutral/charged repeating units to minimize the accumulated charge repulsion on neutral surface. Improved lubricating properties of the graft copolymers compared to the block copolymer...

  3. Structural Studies of Amphiphilic 4-Helix Bundle Peptides Incorporating Designed Extended Chromophores for Nonlinear Optical Biomolecular Materials

    Energy Technology Data Exchange (ETDEWEB)

    Strzalka,J.; Xu, T.; Tronin, A.; Wu, S.; Miloradovic, I.; Kuzmenko, I.; Gog, T.; Therien, M.; Blasie, K.

    2006-01-01

    Extended conjugated chromophores containing (porphinato)zinc components that exhibit large optical polarizabilities and hyperpolarizabiliites are incorporated into amphiphilic 4-helix bundle peptides via specific axial histidyl ligation of the metal. The bundle's designed amphiphilicity enables vectorial orientation of the chromophore/peptide complex in macroscopic monolayer ensembles. The 4-helix bundle structure is maintained upon incorporation of two different chromophores at stoichiometries of 1-2 per bundle. The axial ligation site appears to effectively control the position of the chromophore along the length of the bundle.

  4. A novel, efficient CNTFET Galois design as a basic ternary-valued logic field.

    Science.gov (United States)

    Keshavarzian, Peiman; Mirzaee, Mahla Mohammad

    2012-01-01

    This paper presents arithmetic operations, including addition and multiplication, in the ternary Galois field through carbon nanotube field-effect transistors (CNTFETs). Ternary logics have received considerable attention among all the multiple-valued logics. Multiple-valued logics are an alternative to common-practice binary logic, which mostly has been expanded from ternary (three-valued) logic. CNTFETs are used to improve Galois field circuit performance. In this study, a novel design technique for ternary logic gates based on CNTFETs was used to design novel, efficient Galois field circuits that will be compared with the existing resistive-load CNTFET circuit designs. In this paper, by using carbon nanotube technology and avoiding the use of resistors, we will reduce power consumption and delay, and will also achieve a better product. Simulation results using HSPICE illustrate substantial improvement in speed and power consumption.

  5. Serpentine diffusion trajectories and the Ouzo effect in partially miscible ternary liquid mixtures

    NARCIS (Netherlands)

    Krishna, R.

    2015-01-01

    This work investigates the transient equilibration process when partially miscible ternary liquid mixtures of two different compositions are brought into contact with each other. Diffusional coupling effects are shown to become increasingly significant as the mixture compositions approach the

  6. Thermodynamic optimization and phase equilibria in the ternary system Ni–Sn–Zn

    Energy Technology Data Exchange (ETDEWEB)

    Gandova, V., E-mail: gandova_71@abv.bg [University of Food Technologies, Inorganic and Physical Chemistry Department, 26 Mariza avenue, 4000 Plovdiv (Bulgaria); Vassilev, G.P. [University of Plovdiv, Faculty of Chemistry, 24 Tsar Asen str., 4000 Plovdiv (Bulgaria)

    2014-10-01

    Highlights: • Thermodynamic description of the Ni–Sn–Zn system was obtained. • Six isothermal sections were calculated. • Third constituents solubility in binary phases’ extensions were taken into account. • Good correlation between calculated and experimental data was obtained. - Abstract: Recent experimental results obtained by differential scanning calorimetry, Scanning Electron Microscopy and other methods were used to develop a thermodynamic description of the ternary system Ni–Sn–Zn. Four ternary non-stoichiometric compounds (T1–T4), mentioned in the literature, were described using three-sublattice models. Previously known optimizations of the binary subsystems were remodeled to comply with the new experimental data. The solubility of the respective ternary components, i.e., Zn in Ni–Sn phases and Sn in Ni–Zn phases, were taken into account and optimized ternary parameters were derived. Six isothermal sections were calculated using Thermo-Calc software.

  7. A novel ternary quantum-dot cell for solving majority voter gate problem

    Science.gov (United States)

    Tehrani, Mohammad A.; Bahrami, Safura; Navi, Keivan

    2014-03-01

    Since the complementary metal-oxide semiconductor (CMOS) technology has experienced many serious problems in fulfilling the need for more robust and efficient circuits, some emerging nanotechnologies have been introduced as the candidates for replacing CMOS. Quantum-dot cellular automata (QCA) is one of the promising nanotechnology candidates with majority function as its fundamental logic element. It has one implementation in binary QCA and several implantations in ternary QCA, but none of the ternary QCA implementations are as efficient as the binary one. In this paper, a new cell configuration for ternary QCA is proposed which works as well as previous cell configuration. Also, a new design for ternary QCA majority function is proposed which performs faster and occupies less area.

  8. Ternary and Multi-Bit FIR Filter Area-Performance Tradeoffs in FPGA

    Directory of Open Access Journals (Sweden)

    Khalil-Ur-Rahman Dayo

    2013-01-01

    Full Text Available In this paper, performance and area of conventional FIR (Finite Impulse Responce filters versus ternary sigma delta modulated FIR filter is compared in FPGA (Field Programmable Gate Arrays using VHDL (Verilog Description Language. Two different approaches were designed and synthesized at same spectral performance by obtaining a TIR (Target Impulse Response. Both filters were synthesized on adaptive LUT (Look Up Table FPGA device in pipelined and non-pipelined modes. It is shown that the Ternary FIR filter occupies approximately the same area as the corresponding multi-bit filter, but for a given specification, the ternary FIR filter has 32% better performance in non-pipelined and 72% in pipelined mode, compared to its equivalent Multi-Bit filter at its optimum 12-bit coefficient quantization. These promising results shows that ternary logic based (i.e. +1,0,-1 filters can be used for huge chip area savings and higher performance.

  9. Multiple vertebral fluid-fluid levels

    Energy Technology Data Exchange (ETDEWEB)

    Bladt, O.; Demaerel, P.; Catry, F.; Breuseghem, I. Van [University Hospitals Gasthuisberg, Department of Radiology, Leuven (Belgium); Ballaux, F. [University Hospitals Gasthuisberg, Department of Pathology, Leuven (Belgium); Samson, I. [University Hospitals Gasthuisberg, Department of Orthopedic Surgery, Leuven (Belgium)

    2004-11-01

    We present a case of multiple vertebral metastases, with multiple fluid-fluid levels, from a moderately to poorly differentiated carcinoma of unknown origin. We suggest that fluid-fluid levels in multiple vertebral lesions are highly suggestive of bone metastases. (orig.)

  10. Binary Ternary Based Nanolaminates Fabricated By Multi Stationary Target PLD (Preprint)

    Science.gov (United States)

    2017-04-04

    AFRL-RX-WP-JA-2017-0306 BINARY- TERNARY BASED NANOLAMINATES FABRICATED BY MULTI-STATIONARY TARGET PLD (PREPRINT) Steven R. Smith...December 2013 – 15 July 2016 4. TITLE AND SUBTITLE BINARY- TERNARY BASED NANOLAMINATES FABRICATED BY MULTI-STATIONARY TARGET PLD (PREPRINT) 5a...energy of 450 mJ per pulse, a galvanometer mirror system and a background pressure of oxygen. Trends in material properties were identified by

  11. Partially fluorinated aarylene polyethers and their ternary blends with PBI and H3PO4

    DEFF Research Database (Denmark)

    Li, Qingfeng; Jensen, Jens Oluf; Pan, Chao

    2008-01-01

    Ternary blend membranes based on sulphonated partially fluorinated arylene polyether, polybenzimidazole (PBI) and phosphoric acid were prepared and characterised as electrolyte for high temperature proton exchange membrane fuel cells. Partially fluorinated arylene polyether was first prepared from......% and modulus of 50 MPa at 150 degrees C. Based on these ternary membranes large MEAs with an active area of 256 cm(2) have been prepared for a 2 kW(el) stack showing good performance and reproducibility....

  12. Toward Multi Principal Component Alloy Discovery: Assessment of the CALPHAD Approach for Ternary (Preprint)

    Science.gov (United States)

    2016-09-15

    phase names such as “ sigma ” or “r- phase ” were disregarded. Of the ternaries evaluated, 14% of the systems have a phase that is only present with a...principal element systems. However, the uncertainty of phase equilibria predictions within these regions is unknown. This study assesses the current...capabilities of a commercially available CALPHAD databases to accurately predict phase equilibria within ternary phase space as a function of the number

  13. Ternary Organic Solar Cells Based on Two Compatible Nonfullerene Acceptors with Power Conversion Efficiency >10.

    Science.gov (United States)

    Liu, Tao; Guo, Yuan; Yi, Yuanping; Huo, Lijun; Xue, Xiaonan; Sun, Xiaobo; Fu, Huiting; Xiong, Wentao; Meng, Dong; Wang, Zhaohui; Liu, Feng; Russell, Thomas P; Sun, Yanming

    2016-12-01

    Two different nonfullerene acceptors and one copolymer are used to fabricate ternary organic solar cells (OSCs). The two acceptors show unique interactions that reduce crystallinity and form a homogeneous mixed phase in the blend film, leading to a high efficiency of ≈10.3%, the highest performance reported for nonfullerene ternary blends. This work provides a new approach to fabricate high-performance OSCs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Silk flame retardant finish by ternary silica sol containing boron and nitrogen

    Science.gov (United States)

    Zhang, Qiang-hua; Chen, Guo-qiang; Xing, Tie-ling

    2017-11-01

    A ternary flame retardant sol system containing Si, B and N was prepared via sol gel method using tetraethoxysilane (TEOS) as a precursor, boric acid (H3BO3) and urea (CO(NH2)2) as flame retardant additives and then applied to silk fabric flame retardant finish. The FT-IR and SEM results showed that the nitrogen-boron-silica ternary sol was successfully prepared and entrapped onto the surface of silk fibers. The limiting oxygen index (LOI) test indicated that the silk fabric treated with 24% boric acid and 6% urea (relative to the TEOS) doped ternary silica sol system performed excellent flame retardancy with the LOI value of 34.6%. Furthermore, in order to endow silk fabric with durable flame retardancy, the silk fabric was pretreated with 1,2,3,4-butanetetracarboxylic acid (BTCA) before the ternary sol system treatment. The BTCA pretreat ment applied to silk could effectively promote the washing durability of the ternary sol, and the LOI value of the treated sample after 10 times washing could still maintain at 30.8% compared with that of 31.0% before washing. Thermo gravimetric (TG), micro calorimeter combustion (MCC) and smoke density test results demonstrated that the thermal stability, heat release and smoke suppression of the nitrogen-boron-silica ternary system decreased somewhat compared with the boron-silica binary flame retardant system.

  15. Hydrophobic cotton textile surfaces using an amphiphilic graphene oxide (GO) coating

    Science.gov (United States)

    Tissera, Nadeeka D.; Wijesena, Ruchira N.; Perera, J. Rangana; de Silva, K. M. Nalin; Amaratunge, Gehan A. J.

    2015-01-01

    We report for the first time hydrophobic properties on cotton fabric successfully achieved by grafting graphene oxide on the fabric surface, using a dyeing method. Graphite oxide synthesized by oxidizing natural flake graphite employing improved Hummer's method showed an inter layer spacing of ∼1 nm from XRD. Synthesized graphite oxide was exfoliated in water using ultrasound energy to obtain graphene oxide (GO). AFM data obtained for the graphene oxide dispersed in an aqueous medium revealed a non-uniform size distribution. FTIR characterization of the synthesized GO sheets showed both hydrophilic and hydrophobic functional groups present on the nano sheets giving them an amphiphilic property. GO flakes of different sizes were successfully grafted on to a cotton fabric surface using a dip dry method. Loading different amounts of graphene oxide on the cotton fiber surface allowed the fabric to demonstrate different degrees of hydrophobicity. The highest observed water contact angle was at 143° with the highest loading of graphene oxide. The fabric surfaces grafted with GO also exhibits adhesive type hydrophobicity. Microscopic characterization of the fiber surface using SEM and AFM reveals the deposition of GO sheets on the fiber surface as a conformal coating. Analysis of the fabric surface using UV-vis absorption allowed identification of the ratio of hydrophobic to hydrophilic domains present on the GO coated cotton fabric surface. Hydrophobic properties on cotton fabric are ascribed to two dimensional amphiphilic properties of deposited GO nano sheets, which successfully lower the interfacial energy of the fabric surface.

  16. Preparation and Investigation of Amphiphilic Block Copolymers/Fullerene Nanocomposites as Nanocarriers for Hydrophobic Drug

    Directory of Open Access Journals (Sweden)

    Qinggang Tan

    2017-02-01

    Full Text Available Biopolymer/inorganic material nanocomposites have attracted increasing interest as nanocarriers for delivering drugs owing to the combined advantages of both biopolymer and inorganic materials. Here, amphiphilic block copolymer/fullerene nanocomposites were prepared as nanocarriers for hydrophobic drug by incorporation of C60 in the core of methoxy polyethylene glycol-poly(d,l-lactic acid (MPEG-PDLLA micelles. The structure and morphology of MPEG-PDLLA/C60 nanocomposites were characterized using transmission electron microscopy, dynamic light scattering, high-resolution transmission electron microscopy, and thermal gravimetric analysis. It was found that the moderate amount of spherical C60 incorporated in the MPEG-PDLLA micelles may cause an increase in the molecular chain space of PDLLA segments in the vicinity of C60 and, thus, produce a larger cargo space to increase drug entrapment and accelerate the drug release from nanocomposites. Furthermore, sufficient additions of C60 perhaps resulted in an aggregation of C60 within the micelles that decreased the drug entrapment and produced a steric hindrance for DOX released from the nanocomposites. The results obtained provide fundamental insights into the understanding of the role of C60 in adjusting the drug loading and release of amphiphilic copolymer micelles and further demonstrate the future potential of the MPEG-PDLLA/C60 nanocomposites used as nanocarriers for controlled drug-delivery applications.

  17. Peptides at the Interface: Self-Assembly of Amphiphilic Designer Peptides and Their Membrane Interaction Propensity.

    Science.gov (United States)

    Kornmueller, Karin; Lehofer, Bernhard; Meindl, Claudia; Fröhlich, Eleonore; Leitinger, Gerd; Amenitsch, Heinz; Prassl, Ruth

    2016-11-14

    Self-assembling amphiphilic designer peptides have been successfully applied as nanomaterials in biomedical applications. Understanding molecular interactions at the peptide-membrane interface is crucial, since interactions at this site often determine (in)compatibility. The present study aims to elucidate how model membrane systems of different complexity (in particular single-component phospholipid bilayers and lipoproteins) respond to the presence of amphiphilic designer peptides. We focused on two short anionic peptides, V4WD2 and A6YD, which are structurally similar but showed a different self-assembly behavior. A6YD self-assembled into high aspect ratio nanofibers at low peptide concentrations, as evidenced by synchrotron small-angle X-ray scattering and electron microscopy. These supramolecular assemblies coexisted with membranes without remarkable interference. In contrast, V4WD2 formed only loosely associated assemblies over a large concentration regime, and the peptide promoted concentration-dependent disorder on the membrane arrangement. Perturbation effects were observed on both membrane systems although most likely induced by different modes of action. These results suggest that membrane activity critically depends on the peptide's inherent ability to form highly cohesive supramolecular structures.

  18. Effect of Al2O3 nanoparticles on bacterial membrane amphiphilic biomolecules.

    Science.gov (United States)

    Jiang, Wei; Ghosh, Saikat; Song, Lei; Vachet, Richard W; Xing, Baoshan

    2013-02-01

    Lipopolysaccharide (LPS) and l-α-phosphatidyl-ethanolamine (PE) are amphiphilic biomolecules that are key constituents in the outer cell membranes of Gram-negative bacteria. In this study, micelles and vesicles of LPS/PE were used as cell membrane models to evaluate nanoparticle (NP) effects on membrane structure. Using atomic force microscopy and sorption experiments, we observed that LPS vesicles were dispersed by Al(2)O(3) NPs because of the strong attachment between LPS polysaccharide chain and oxide surface. LPS coated on the Al(2)O(3) NPs, and formed a layer of tens of nanometer as shown from atom force microscopy (AFM) images. High pH, ionic strength and sulfate concentration inhibited the adsorption of LPS molecules on NPs. The features of PE vesicles were changed after exposing to Al(2)O(3) NPs, inducing large round vesicles with detectable thickness as revealed by AFM, resulting in the increase of vesicle diameter. The aqueous stability of PE was disturbed when adding Al(2)O(3) NPs, but was enhanced by increasing pH. The interaction between NPs and membrane amphiphilic biomolecules may affect membrane fluidity, integrity and lateral organization, which is important for NP safety evaluation and for new NP designs in biological and biomedical applications. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Amphiphilic perylene-calix[4]arene hybrids: synthesis and tunable self-assembly.

    Science.gov (United States)

    Rodler, Fabian; Schade, Boris; Jäger, Christof M; Backes, Susanne; Hampel, Frank; Böttcher, Christoph; Clark, Timothy; Hirsch, Andreas

    2015-03-11

    The first highly water-soluble perylene-calix[4]arene hybrid with the calixarene scaffold acting as a structure-determining central platform is presented. In this tetrahedrally shaped amphiphilic architecture the hydrophilic and hydrophobic subunits are oriented at the opposite side of the calixarene platform. The hydrophobic part contains the two perylene diimide moieties, which enable strong π-π interactions in self-assembly processes. Two hydrophilic Newkome-type dendrons provide sufficient water solubility at slightly basic conditions. The tetrahedrally shaped amphiphile displays an unprecedented aggregation behavior down to concentrations as low as 10(-7) mol L(-1). The intriguing self-assembly process of the compound in water as well as under changed polarity conditions, achieved by addition of THF, could be monitored by the complemented use of cryogenic transmission electron microscopy (cryo-TEM), UV-vis spectroscopy, and fluorescence spectroscopy. Molecular-dynamics and molecular modeling simulations helped in understanding the interplay of supramolecular and optical behavior.

  20. Polydispersity-Driven Block Copolymer Amphiphile Self-Assembly into Prolate-Spheroid Micelles

    Energy Technology Data Exchange (ETDEWEB)

    Schmitt, Andrew L.; Repollet-Pedrosa, Milton H.; Mahanthappa, Mahesh K. (UW)

    2013-09-26

    The aqueous self-assembly behavior of polydisperse poly(ethylene oxide-b-1,4-butadiene-b-ethylene oxide) (OBO) macromolecular triblock amphiphiles is examined to discern the implications of continuous polydispersity in the hydrophobic block on the resulting aqueous micellar morphologies of otherwise monodisperse polymer surfactants. The chain length polydispersity and implicit composition polydispersity of these samples furnishes a distribution of preferred interfacial curvatures, resulting in dilute aqueous block copolymer dispersions exhibiting coexisting spherical and rod-like micelles with vesicles in a single sample with a O weight fraction, w{sub O}, of 0.18. At higher w{sub O} = 0.51-0.68, the peak in the interfacial curvature distribution shifts and we observe the formation of only American football-shaped micelles. We rationalize the formation of these anisotropically shaped aggregates based on the intrinsic distribution of preferred curvatures adopted by the polydisperse copolymer amphiphiles and on the relief of core block chain stretching by chain-length-dependent intramicellar segregation.

  1. Hydrophobic amino acids grafted onto chitosan: a novel amphiphilic chitosan nanocarrier for hydrophobic drugs.

    Science.gov (United States)

    Motiei, Marjan; Kashanian, Soheila; Taherpour, Avat Arman

    2017-01-01

    The objective of this study is to develop a novel biocompatible amphiphilic drug delivery for hydrophobic drugs, chitosan (CS) was grafted to a series of hydrophobic amino acids including l-alanine (A), l-proline (P), and l-tryptophan (W) by carbodiimide mediated coupling reaction. Chemical characteristics of the modified polymers were determined and confirmed by FT-IR, (1)H NMR, and UV-vis spectroscopy and the degree of substitution was quantified by elemental analysis. The modified polymers were used to form amphiphilic chitosan nanocarriers (ACNs) by the conventional self-assembly method using ultrasound technique. The morphology and the size of ACNs were analyzed by scanning electron microscope (SEM) and Dynamic light scattering (DLS). The sizes of spherical ACNs analyzed by SEM were obviously smaller than those of determined by DLS. The ACNs effectively surrounded the hydrophobic model drug, letrozole (LTZ), and demonstrated different encapsulation efficiencies (EE), loading capacities (LC), and controlled drug release profiles. The characteristics of ACNs and the mechanism of drug encapsulation were confirmed by molecular modeling method. The modeling of the structures of LTZ, profiles of A, P, and W grafted onto CS and the wrapping process around LTZ was performed by quantum mechanics (QM) methods. There was a good agreement between the experimental and theoretical results. The cell viability was also evaluated in two cell lines compared with free drug by MTT assay. The hydrophobic portion effects on ACNs' characteristics and the proper selection of amino acid demonstrate a promising potential for drug delivery vector.

  2. Hydration-Induced Phase Separation in Amphiphilic Polymer Matrices and its Influence on Voclosporin Release

    Energy Technology Data Exchange (ETDEWEB)

    Khan, I. John [The State Univ. of New Jersey, Piscataway, NJ (United States); Murthy, N. Sanjeeva [The State Univ. of New Jersey, Piscataway, NJ (United States); Kohn, Joachim [The State Univ. of New Jersey, Piscataway, NJ (United States)

    2015-10-30

    Voclosporin is a highly potent, new cyclosporine -- a derivative that is currently in Phase 3 clinical trials in the USA as a potential treatment for inflammatory diseases of the eye. Voclosporin represents a number of very sparingly soluble drugs that are difficult to administer. It was selected as a model drug that is dispersed within amphiphilic polymer matrices, and investigated the changing morphology of the matrices using neutron and x-ray scattering during voclosporin release and polymer resorption. The hydrophobic segments of the amphiphilic polymer chain are comprised of desaminotyrosyl-tyrosine ethyl ester (DTE) and desaminotyrosyl-tyrosine (DT), and the hydrophilic component is poly(ethylene glycol) (PEG). Water uptake in these matrices resulted in the phase separation of hydrophobic and hydrophilic domains that are a few hundred Angstroms apart. These water-driven morphological changes influenced the release profile of voclosporin and facilitated a burst-free release from the polymer. No such morphological reorganization was observed in poly(lactide-co-glycolide) (PLGA), which exhibits an extended lag period, followed by a burst-like release of voclosporin when the polymer was degraded. An understanding of the effect of polymer composition on the hydration behavior is central to understanding and controlling the phase behavior and resorption characteristics of the matrix for achieving long-term controlled release of hydrophobic drugs such as voclosporin.

  3. Solubilization of poorly water-soluble compounds using amphiphilic phospholipid polymers with different molecular architectures.

    Science.gov (United States)

    Mu, Mingwei; Konno, Tomohiro; Inoue, Yuuki; Ishihara, Kazuhiko

    2017-10-01

    To achieve stable and effective solubilization of poorly water-soluble bioactive compounds, water-soluble and amphiphilic polymers composed of hydrophilic 2-methacryloyloxyethyl phosphorylcholine (MPC) units and hydrophobic n-butyl methacrylate (BMA) units were prepared. MPC polymers having different molecular architectures, such as random-type monomer unit sequences and block-type sequences, formed polymer aggregates when they were dissolved in aqueous media. The structure of the random-type polymer aggregate was loose and flexible. On the other hand, the block-type polymer formed polymeric micelles, which were composed of very stable hydrophobic poly(BMA) cores and hydrophilic poly(MPC) shells. The solubilization of a poorly water-soluble bioactive compound, paclitaxel (PTX), in the polymer aggregates was observed, however, solubilizing efficiency and stability were strongly depended on the polymer architecture; in other words, PTX stayed in the poly(BMA) core of the polymer micelle formed by the block-type polymer even when plasma protein was present in the aqueous medium. On the other hand, when the random-type polymer was used, PTX was transferred from the polymer aggregate to the protein. We conclude that water-soluble and amphiphilic MPC polymers are good candidates as solubilizers for poorly water-soluble bioactive compounds. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. One-Dimensional Supramolecular Nanoplatforms for Theranostics Based on Co-Assembly of Peptide Amphiphiles.

    Science.gov (United States)

    Kim, Inhye; Han, Eun Hee; Ryu, Jooyeon; Min, Jin-Young; Ahn, Hyungju; Chung, Young-Ho; Lee, Eunji

    2016-10-10

    We report a simple and facile strategy for the preparation of multifunctional nanoparticles with programmable properties using self-assembly of precisely designed block amphiphiles in an aqueous solution-state. Versatile, supramolecular nanoplatform for personalized needs, particularly-theranostics, was fabricated by coassembly of peptide amphiphiles (PAs) in aqueous solution, replacing time-consuming and inaccessible chemical synthesis. Fibrils, driven by the assembly of hydrophobic β-sheet-forming peptide block, were utilized as a nanotemplate for drug loading within their robust core. PAs were tagged with octreotide [somatostatin (SST) analogue] for tumor-targeting or were conjugated with paramagnetic metal ion (Gd3+)-chelating 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) for magnetic resonance (MR) imaging. The two PA types were coassembled to integrate each PA function into original fibrillar nanotemplates. The adoption of a bulky target-specific cyclic octreotide and β-sheet-forming peptide with enhanced hydrophobicity led to a morphological transition from conventional fibrils to helical fibrils. The resulting one-dimensional nanoaggregates allowed the successful intracellular delivery of doxorubicin (DOX) to MCF-7 cancer cells overexpressing SST receptor (SSTR) and MR imaging by enabling high longitudinal (T1) relaxivity of water protons. Correlation between the structural nature of fibrils formed by PA coassembly and contrast efficacy was elucidated. The coassembly of PAs with desirable functions may thus be a useful strategy for the generation of tailor-made biocompatible nanomaterials.

  5. Removal of volatile organic compounds using amphiphilic cyclodextrin-coated polypropylene

    Directory of Open Access Journals (Sweden)

    Ludmilla Lumholdt

    2014-11-01

    Full Text Available Polypropylene nonwovens were functionalised using a self-assembled, amphiphilic cyclodextrin coating and the potential for water purification by removal of pollutants was studied. As benzene is one of the problematic compounds in the Water Framework Directive, six volatile organic compounds (benzene and five benzene-based substances were chosen as model compounds. The compounds were tested as a mixture in order to provide a more realistic situation since the wastewater will be a complex mixture containing multiple pollutants. The volatile organic compounds are known to form stable inclusion complexes with cyclodextrins. Six different amphiphilic cyclodextrin derivatives were synthesised in order to elucidate whether or not the uptake abilities of the coating depend on the structure of the derivative. Headspace gas chromatography was used for quantification of the uptake exploiting the volatile nature of benzene and its derivatives. The capacity was shown to increase beyond the expected stoichiometries of guest–host complexes with ratios of up to 16:1.

  6. Amphiphilic nanoparticles suppress droplet break-up in a concentrated emulsion flowing through a narrow constriction.

    Science.gov (United States)

    Gai, Ya; Kim, Minkyu; Pan, Ming; Tang, Sindy K Y

    2017-05-01

    This paper describes the break-up behavior of a concentrated emulsion comprising drops stabilized by amphiphilic silica nanoparticles flowing in a tapered microchannel. Such geometry is often used in serial droplet interrogation and sorting processes in droplet microfluidics applications. When exposed to high viscous stresses, drops can undergo break-up and compromise their physical integrity. As these drops are used as micro-reactors, such compromise leads to a loss in the accuracy of droplet-based assays. Here, we show droplet break-up is suppressed by replacing the fluoro-surfactant similar to the one commonly used in current droplet microfluidics applications with amphiphilic nanoparticles as droplet stabilizer. We identify parameters that influence the break-up of these drops and demonstrate that break-up probability increases with increasing capillary number and confinement, decreasing nanoparticle size, and is insensitive to viscosity ratio within the range tested. Practically, our results reveal two key advantages of nanoparticles with direct applications to droplet microfluidics. First, replacing surfactants with nanoparticles suppresses break-up and increases the throughput of the serial interrogation process to 3 times higher than that in surfactant system under similar flow conditions. Second, the insensitivity of break-up to droplet viscosity makes it possible to process samples having different composition and viscosities without having to change the channel and droplet geometry in order to maintain the same degree of break-up and corresponding assay accuracy.

  7. Rapidly recovering hydrogel scaffolds from self-assembling diblock copolypeptide amphiphiles

    Science.gov (United States)

    Nowak, Andrew P.; Breedveld, Victor; Pakstis, Lisa; Ozbas, Bulent; Pine, David J.; Pochan, Darrin; Deming, Timothy J.

    2002-05-01

    Protein-based hydrogels are used for many applications, ranging from food and cosmetic thickeners to support matrices for drug delivery and tissue replacement. These materials are usually prepared using proteins extracted from natural sources, which can give rise to inconsistent properties unsuitable for medical applications. Recent developments have utilized recombinant DNA methods to prepare artificial protein hydrogels with specific association mechanisms and responsiveness to various stimuli. Here we synthesize diblock copolypeptide amphiphiles containing charged and hydrophobic segments. Dilute solutions of these copolypeptides would be expected to form micelles; instead, they form hydrogels that retain their mechanical strength up to temperatures of about 90°C and recover rapidly after stress. The use of synthetic materials permits adjustment of copolymer chain length and composition, which we varied to study their effect on hydrogel formation and properties. We find that gelation depends not only on the amphiphilic nature of the polypeptides, but also on chain conformations-α-helix, β-strand or random coil. Indeed, shape-specific supramolecular assembly is integral to the gelation process, and provides a new class of peptide-based hydrogels with potential for applications in biotechnology.

  8. First-order phase transition during displacement of amphiphilic biomacromolecules from interfaces by surfactant molecules

    Science.gov (United States)

    Ettelaie, Rammile; Dickinson, Eric; Pugnaloni, Luis

    2014-11-01

    The adsorption of surfactants onto a hydrophobic interface, already laden with a fixed number of amphiphilic macromolecules, is studied using the self consistent field calculation method of Scheutjens and Fleer. For biopolymers having unfavourable interactions with the surfactant molecules, the adsorption isotherms show an abrupt jump at a certain value of surfactant bulk concentration. Alternatively, the same behaviour is exhibited when the number of amphiphilic chains on the interface is decreased. We show that this sudden jump is associated with a first-order phase transition, by calculating the free energy values for the stable and the metastable states at both sides of the transition point. We also observe that the transition can occur for two approaching surfaces, from a high surfactant coverage phase to a low surfactant coverage one, at sufficiently close separation distances. The consequence of this finding for the steric colloidal interactions, induced by the overlap of two biopolymer + surfactant films, is explored. In particular, a significantly different interaction, in terms of its magnitude and range, is predicted for these two phases. We also consider the relevance of the current study to problems involving the competitive displacement of proteins by surfactants in food colloid systems.

  9. Effects of immobilizing sites of RGD peptides in amphiphilic block copolymers on efficacy of cell adhesion.

    Science.gov (United States)

    Zhang, Zheng; Lai, Yuxiao; Yu, Lin; Ding, Jiandong

    2010-11-01

    This paper examines the effects of immobilizing sites of a bioactive ligand on its biological efficacy in a self assembly biomaterial. We synthesized an amphiphilic block copolymer PCLA-PEG-PCLA (PCLA: poly(epsilon-caprolactone-co-lactide), PEG: poly(ethylene glycol)), and then achieved immobilization of arginine-glycine-aspartate (RGD) peptides into either hydrophobic PCLA blocks or hydrophilic PEG blocks. The block copolymers could self assemble into hydrogels composed of percolated micelle network in water, and the sol-gel transition temperature was adjusted between room and body temperatures. In vitro examinations of chondrocyte viability were performed. We found that immobilization of RGD in hydrophilic blocks enhanced cell adhesion on the corresponding hydrogel surface much more significantly than that in hydrophobic blocks. The difference might come from that RGD ligands in hydrophilic blocks are exposed on the micellar surface in water more than those in hydrophobic blocks. The present research highlights the importance of the immobilizing sites of RGD peptides in amphiphilic polymers on the eventual cell-binding efficacy, and is thus meaningful for guiding the molecular design of bioactive materials. Copyright 2010 Elsevier Ltd. All rights reserved.

  10. Amphiphilic Antifogging/Anti-Icing Coatings Containing POSS-PDMAEMA-b-PSBMA.

    Science.gov (United States)

    Li, Chuan; Li, Xiaohui; Tao, Chao; Ren, Lixia; Zhao, Yunhui; Bai, Shan; Yuan, Xiaoyan

    2017-07-12

    Highly transparent antifogging/anti-icing coatings were developed from amphiphilic block copolymers of polyhedral oligomeric silsesquioxane-poly[2-(dimethylamino)ethyl methacrylate]-block-poly(sulfobetaine methacrylate) (POSS-PDMAEMA-b-PSBMA) with a small amount of ethylene glycol dimethacrylate (EGDMA) via UV-curing. The excellent antifogging properties of the prepared coatings were originated from the hygroscopicity of both PDMAEMA and PSBMA blocks in the semi-interpenetrating polymer network (SIPN) with polymerization of EGDMA and hydrophobic POSS clusters aggregated on the surface. PDMAEMA with a lower critical solution temperature and PSBMA with an upper critical solution temperature in the block copolymers facilitated dispersion and absorption of water molecules into the SIPN coatings, fulfilling the enhanced antifogging function. Analysis of differential scanning calorimetry further confirmed that there was bond water and nonfreezable bond water in the SIPN coatings. The amphiphilic SIPN coatings exhibited the anti-icing ability with a freezing delay time of more than 2 min at -15 °C, owing to the aggregation of hydrophobic POSS groups and the self-lubricating aqueous layer generated by nonfreezable bond water on the surface. The prepared transparent antifogging/anti-icing coatings could have novel potential applications in practice.

  11. Synthesis of an amphiphilic rhodamine derivative and characterization of its solution and thin film properties

    Energy Technology Data Exchange (ETDEWEB)

    Aviv, Hagit [Department of Chemistry, Bar-Ilan University, Ramat-Gan (Israel); Bar-Ilan University Institute for Nanotechnology and Advanced Materials, Ramat-Gan (Israel); Harazi, Sivan [Department of Chemistry, Bar-Ilan University, Ramat-Gan (Israel); Department of Physics, Bar-Ilan University, Ramat-Gan (Israel); Bar-Ilan University Institute for Nanotechnology and Advanced Materials, Ramat-Gan (Israel); Schiff, Dillon [Department of Chemistry, Bar-Ilan University, Ramat-Gan (Israel); Bar-Ilan University Institute for Nanotechnology and Advanced Materials, Ramat-Gan (Israel); Ramon, Yoni [Department of Chemistry, Bar-Ilan University, Ramat-Gan (Israel); Department of Physics, Bar-Ilan University, Ramat-Gan (Israel); Bar-Ilan University Institute for Nanotechnology and Advanced Materials, Ramat-Gan (Israel); Tischler, Yaakov R., E-mail: yrt@biu.ac.il [Department of Chemistry, Bar-Ilan University, Ramat-Gan (Israel); Bar-Ilan University Institute for Nanotechnology and Advanced Materials, Ramat-Gan (Israel)

    2014-08-01

    Here we present characterization of solution and thin film properties of Lissamine rhodamine B sulfonyl didodecyl amine (LRSD), an amphiphilic derivative of rhodamine. LRSD was synthesized by functionalizing Lissamine rhodamine B sulfonyl chloride (LRSC) with didodecylamine via a straightforward sulfonylation reaction. LRSD's long alkane chains make it highly soluble in chloroform, with a marked increase in brightness compared to the starting material. LRSD is shown to form well-defined robust micelles in water, without the addition of a co-surfactant and stable monolayers at the air–water interface. The greater lipophilicity of LRSD also enables doping into non-polar polymeric host matrices such as polystyrene with less aggregation and hence higher fluorescence quantum yield than LRSC or even rhodamine B. The monolayers of LRSD were prepared via Langmuir–Blodgett deposition and showed shifts in the photoluminescence peak from 575 nm to 595 nm, as the surface pressure is varied from 3 mN/m to 11 mN/m. - Highlights: • Lissamine rhodamine B sulfonyl didodecyl amine (LRSD) is soluble in chloroform. • LRSD shows robust quantum yield in solution and as a dopant in thin film. • LRSD is an amphiphilic rhodamine dye that forms compact fluorescent micelles. • LRSD forms a stable isotherm when spread at the air–water interface.

  12. Coating of reverse osmosis membranes with amphiphilic copolymers for biofouling control

    KAUST Repository

    Bucs, Szilard

    2017-05-30

    Surface coating of membranes may be a promising option to control biofilm development and biofouling impact on membrane performance of spiral-wound reverse osmosis (RO) systems. The objective of this study was to investigate the impact of an amphiphilic copolymer coating on biofilm formation and biofouling control. The coating was composed of both hydrophilic and hydrophobic monomers hydroxyethyl methacrylate (HEMA) and perfluorodecyl acrylate (PFA), respectively. Commercial RO membranes were coated with HEMA-PFA copolymer film. Long and short term biofouling studies with coated and uncoated membranes and feed spacer were performed using membrane fouling simulators (MFSs) operated in parallel, fed with water containing nutrients. For the long-term studies pressure drop development in time was monitored and after eight days the MFSs were opened and the accumulated biofilm on the membrane and spacer sheets was quantified and characterized. The presence of the membrane coating was determined using X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). Results showed that the amphiphilic coating (i) delayed biofouling (a lower pressure drop increase by a factor of 3 and a lower accumulated active biomass amount by a factor of 6), (ii) influenced the biofilm composition (23% lower polysaccharides and 132% higher protein content) and (iii) was still completely present on the membrane at the end of the biofouling study, showing that the coating was strongly attached to the membrane surface. Using coated membranes and feed spacers in combination with advanced cleaning strategies may be a suitable way to control biofouling.

  13. Photoisomerization of amphiphilic azobenzene derivatives in Langmuir Blodgett films prepared as polyion complexes, using ionic polymers

    Energy Technology Data Exchange (ETDEWEB)

    Shembekar, Vishakha R. [Department of Chemistry, Indian Institute of Technology, Bombay, Mumbai-400 076 (India); Contractor, A.Q. [Department of Chemistry, Indian Institute of Technology, Bombay, Mumbai-400 076 (India); Major, S.S. [Department of Physics, Indian Institute of Technology, Bombay, Mumbai-400 076 (India); Talwar, S.S. [Department of Physics, Indian Institute of Technology, Bombay, Mumbai-400 076 (India)]. E-mail: chsstia@phy.iitb.ac.in.z

    2006-07-03

    Polyion complexation in mixed Langmuir and Langmuir Blodgett (LB) films of photochromic amphiphilic azobenzene carboxylic acids, 11-[4-(4-hexylphenyl)azo] phenoxyundecanoic acid, 11-(4-phenylazo)phenoxyundecanoic acid, and diamine grafted poly(methylmethaacrylate) polymers has been studied. Monolayer behaviour of the pure components and mixed films was studied through pressure-area isotherms and LB films were characterized by spectroscopic, X-ray diffraction and Atomic force microscopy techniques. Aggregation (H-type), often observed in LB films of pure amphiphilic azo acids, was partly avoided in the mixed LB films as indicated by absorption spectral studies. Photoisomerization of the polyion complexed LB films was also studied. The results altogether demonstrate that amine grafted polymer enter into a polyion complexation with azo acid carboxylate group. LB films could be obtained by transfer of the composite monolayers and these LB films exhibited different levels of aggregation of the azo acids. Reversible photoisomerization was observed in LB films with unaggregated azo acid.

  14. Gold Nanoparticles Protected with Thiol-Derivatized Amphiphilic Poly( -caprolactone)-b-poly(acrylic acid)

    DEFF Research Database (Denmark)

    Javakhishvili, Irakli; Hvilsted, Søren

    2008-01-01

    Amphiphilic poly(c-caprolactone)-b-poly(acrylic acid) (HS-PCL-b-PAA) bearing thiol functionality at the PCL terminal has been synthesized by a combination of ring-opening polymerization (ROP) of c-caprolactone (c-CL), esterification of hydroxy chain end with protected mercaptoacetic acid, subsequ......Amphiphilic poly(c-caprolactone)-b-poly(acrylic acid) (HS-PCL-b-PAA) bearing thiol functionality at the PCL terminal has been synthesized by a combination of ring-opening polymerization (ROP) of c-caprolactone (c-CL), esterification of hydroxy chain end with protected mercaptoacetic acid...... distribution (1.09). The hydroxy chain end of Br-PCL-OR was modified by reacting with a-(2,4-dinitrophenylthio)acetic acid or a-(4methoxytritylthio) acetic acid resulting in heterotelechelic PCL incorporating protected thiol and bromoester functionalities. It was then employed as macroinitiator in NiBr2(PPh3......)2 catalysed ATRP of tBA. ATRP of tBA provided diblock copolymers with low polydispersity index (1.17-1.39) while preserving the protected thiol function. Sequential or simultaneous removal of 2,4-dinitrophenyl or 4-methoxytrityl and tert-butyl ester groups resulted in HS-PCL-b-PAA. The PCL backbone remained...

  15. Preparation and Investigation of Amphiphilic Block Copolymers/Fullerene Nanocomposites as Nanocarriers for Hydrophobic Drug

    Science.gov (United States)

    Tan, Qinggang; Chu, Yanyan; Bie, Min; Wang, Zihao; Xu, Xiaoyan

    2017-01-01

    Biopolymer/inorganic material nanocomposites have attracted increasing interest as nanocarriers for delivering drugs owing to the combined advantages of both biopolymer and inorganic materials. Here, amphiphilic block copolymer/fullerene nanocomposites were prepared as nanocarriers for hydrophobic drug by incorporation of C60 in the core of methoxy polyethylene glycol-poly(d,l-lactic acid) (MPEG-PDLLA) micelles. The structure and morphology of MPEG-PDLLA/C60 nanocomposites were characterized using transmission electron microscopy, dynamic light scattering, high-resolution transmission electron microscopy, and thermal gravimetric analysis. It was found that the moderate amount of spherical C60 incorporated in the MPEG-PDLLA micelles may cause an increase in the molecular chain space of PDLLA segments in the vicinity of C60 and, thus, produce a larger cargo space to increase drug entrapment and accelerate the drug release from nanocomposites. Furthermore, sufficient additions of C60 perhaps resulted in an aggregation of C60 within the micelles that decreased the drug entrapment and produced a steric hindrance for DOX released from the nanocomposites. The results obtained provide fundamental insights into the understanding of the role of C60 in adjusting the drug loading and release of amphiphilic copolymer micelles and further demonstrate the future potential of the MPEG-PDLLA/C60 nanocomposites used as nanocarriers for controlled drug-delivery applications. PMID:28772552

  16. The non-peptidic part determines the internalization mechanism and intracellular trafficking of peptide amphiphiles.

    Directory of Open Access Journals (Sweden)

    Dimitris Missirlis

    Full Text Available BACKGROUND: Peptide amphiphiles (PAs are a class of amphiphilic molecules able to self-assemble into nanomaterials that have shown efficient in vivo targeted delivery. Understanding the interactions of PAs with cells and the mechanisms of their internalization and intracellular trafficking is critical in their further development for therapeutic delivery applications. METHODOLOGY/PRINCIPAL FINDINGS: PAs of a novel, cell- and tissue-penetrating peptide were synthesized possessing two different lipophilic tail architectures and their interactions with prostate cancer cells were studied in vitro. Cell uptake of peptides was greatly enhanced post-modification. Internalization occurred via lipid-raft mediated endocytosis and was common for the two analogs studied. On the contrary, we identified the non-peptidic part as the determining factor of differences between intracellular trafficking and retention of PAs. PAs composed of di-stearyl lipid tails linked through poly(ethylene glycol to the peptide exhibited higher exocytosis rates and employed different recycling pathways compared to ones consisting of di-palmitic-coupled peptides. As a result, cell association of the former PAs decreased with time. CONCLUSIONS/SIGNIFICANCE: Control over peptide intracellular localization and retention is possible by appropriate modification with synthetic hydrophobic tails. We propose this as a strategy to design improved peptide-based delivery systems.

  17. Discriminating binding and positioning of amphiphiles to lipid bilayers by {sup 1}H NMR

    Energy Technology Data Exchange (ETDEWEB)

    Evanics, F. [Department of Chemistry, University of Toronto, UTM, 3359 Mississauga Rd. North Mississauga, Ont., L5L 1C6 (Canada); Prosser, R.S. [Department of Chemistry, University of Toronto, UTM, 3359 Mississauga Rd. North Mississauga, Ont., L5L 1C6 (Canada)]. E-mail: sprosser@utm.utoronto.ca

    2005-04-04

    The binding and positioning in lipid bilayers of three well-known drugs--imipramine, nicotine, and caffeine--have been studied using {sup 1}H NMR. The membrane model system consisted of 'fast-tumbling' lipid bicelles, in which a bilayered lipid domain, composed of the unsaturated lipid, 1,2-dimyristelaidoyl-sn-glycero-3-phosphocholine (DMLPC) was surrounded by a rim of deuterated detergent-like lipids, consisting of 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC-d22). Binding and immersion depth information was obtained by three experiments. (1) {sup 1}H chemical shift perturbations, upon transfer of the amphiphiles from water to a bicelle mixture, were used to estimate regions of the amphiphiles that interact with the membrane. (2) Water contact to resolvable protons was measured through a Nuclear Overhauser Effect (NOE) between water and resolvable drug and lipid resonances. In the case of both lipids and membrane bound drugs, positive NOEs with large cross-relaxation rates were measured for most resonances originating from the membrane hydrophilic region, while negative NOEs were observed predominantly to resonances in the hydrophobic region of the membrane. (3) {sup 1}H NMR measurements of oxygen-induced (paramagnetic) spin-lattice relaxation rates, which are known to increase with membrane immersion depth, were used to corroborate conclusions based on chemical shift perturbations and water-ligand NOEs.

  18. Dilational rheology of oil/water interfaces covered by amphiphilic polysaccharides derived from dextran.

    Science.gov (United States)

    Desbrières, Jacques; López-Gonzalez, Edeluc; Aguilera-Miguel, Antonio; Sadtler, Véronique; Marchal, Philippe; Castel, Christophe; Choplin, Lionel; Durand, Alain

    2017-12-01

    This work studied the adsorption at dodecane/water interface of amphiphilic polysaccharides derived from dextran (a nonionic bacterial polysaccharide) by random attachment of phenoxy groups along the chains (between 10 and 20 attached phenoxy groups per 100 glucose repeat units). The long-time kinetics of interfacial tension decrease was satisfactorily described assuming diffusion-limited adsorption of hydrophobic units (over 4h). Dilational rheology of dodecane/water interface was studied for the first time with that kind of amphiphilic polysaccharides and evidenced a significant elastic component. For all dextran derivatives, experimental results were conveniently described using Lucassen-van den Tempel model which assumed diffusion-limited of surface active species. The characteristic frequency increased with the number of attached phenoxy groups and its order of magnitude (10 -3 -10 -2 rad.s -1 ) was consistent with estimations based on the previous model. Experimental results were compared to those obtained with commercial stabilizers like Pluronics (L64, P105, F68 and F127) and Tween 80. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Synthesis and cell imaging applications of amphiphilic AIE-active poly(amino acid)s.

    Science.gov (United States)

    Tian, Jianwen; Jiang, Ruming; Gao, Peng; Xu, Dazhuang; Mao, Liucheng; Zeng, Guangjian; Liu, Meiying; Deng, Fengjie; Zhang, Xiaoyong; Wei, Yen

    2017-10-01

    The poly(amino acid)s based biomaterials have attracted great research attention over the past few decades because of their biocompatibility, biodegradability and well designability. Although much progress has achieved in the synthesis and biomedical applications of poly(amino acid)s, the synthesis of luminescent poly(amino acid)s has been rarely reported. In this work, novel amphiphilic luminescent poly(amino acid)s with aggregation-induced emission (AIE) feature have been synthesized by a new approach of controlling N-carboxy anhydride (NCA) ring-opening polymerization, in which hydrophobic 2-(4-aminophenyl)-3-(10-hexadecyl-4H-phenothiazin-3-yl)acrylonitrile (Phe-NH2) with AIE feature was used as initiator and hydrophilic oligomeric glycol functionalized glutamate (OEG-glu) NCA was acted as monomer. The successful synthesis of final Phe-OEG-Pglu polymers was confirmed by different characterization techniques. Phe-OEG-Pglu polymers possess amphiphilic properties and can self-assemble into luminescent polymeric nanoparticles (LPNs). Based on cellular imaging experiments, we demonstrated that Phe-OEG-Pglu LPNs have great potential for bio-imaging applications due to their attractive properties including strong fluorescence intensity, great water dispersibility, excellent biocompatibility and high cellular uptake efficiency. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Surface Structure and Hydration of Sequence-Specific Amphiphilic Polypeptoids for Antifouling/Fouling Release Applications.

    Science.gov (United States)

    Leng, Chuan; Buss, Hilda G; Segalman, Rachel A; Chen, Zhan

    2015-09-01

    Amphiphilic polypeptoids can be designed with specific sequences of hydrophilic and hydrophobic units, which determine their surface properties for antifouling/fouling release purposes. Although the sequence-dependent surface structures of polypeptoids have been extensively investigated, e.g., with X-ray spectroscopy, their molecular structures under the aqueous conditions relevant to marine fouling have not been studied. In this work, we applied sum frequency generation (SFG) vibrational spectroscopy to study the surface structures and hydration of a series of amphiphilic polypeptoid coatings with different sequences in air and water. SFG spectra, in agreement with X-ray spectroscopy studies, revealed that the surface coverage of the hydrophilic N-(2-methoxyethyl)glycine (Nme) units in air is affected by both the number and position of the hydrophobic N-(heptafluorobutyl)glycine (NF) units in the peptoid chain and is negatively correlated with the surface concentration of the fluorine element. Our ability to probe the SFG signals of water molecules at the peptoid surface provides new information on the hydrated film properties. From these SFG signals and the time evolution of water contact angles on the polymers, we see that the hydrated film properties are also dependent upon the peptoid sequence. This work indicates that the surface presence of the Nme groups and the ability of the polymers to order and strongly hydrogen bond with interfacial water molecules determine their antifouling properties, whereas the surface restructuring rate upon contact with water affects their fouling release behaviors.

  1. Amphiphilic self-assembled polymeric copper catalyst to parts per million levels: click chemistry.

    Science.gov (United States)

    Yamada, Yoichi M A; Sarkar, Shaheen M; Uozumi, Yasuhiro

    2012-06-06

    Self-assembly of copper sulfate and a poly(imidazole-acrylamide) amphiphile provided a highly active, reusable, globular, solid-phase catalyst for click chemistry. The self-assembled polymeric Cu catalyst was readily prepared from poly(N-isopropylacrylamide-co-N-vinylimidazole) and CuSO(4) via coordinative convolution. The surface of the catalyst was covered with globular particles tens of nanometers in diameter, and those sheetlike composites were layered to build an aggregated structure. Moreover, the imidazole units in the polymeric ligand coordinate to CuSO(4) to give a self-assembled, layered, polymeric copper complex. The insoluble amphiphilic polymeric imidazole Cu catalyst with even 4.5-45 mol ppm drove the Huisgen 1,3-dipolar cycloaddition of a variety of alkynes and organic azides, including the three-component cyclization of a variety of alkynes, organic halides, and sodium azide. The catalytic turnover number and frequency were up to 209000 and 6740 h(-1), respectively. The catalyst was readily reused without loss of catalytic activity to give the corresponding triazoles quantitatively.

  2. Amphiphilic nanocapsules entangled with organometallic coordination polymers for controlled cargo release.

    Science.gov (United States)

    Liang, Guodong; Ni, Huan; Bao, Suping; Zhu, Fangming; Gao, Haiyang; Wu, Qing; Tang, Ben Zhong

    2014-06-03

    A class of new amphiphilic nanocapsules entangled with organometallic coordination polymers has been developed for the first time. Poly(2-(N,N-dimethyl amino)ethyl methacrylate)-b-polystyrene capped with β-cyclodextrin (β-CD) (CD-PDMAEMA-b-PS) is first synthesized using sequent RAFT polymerization of styrene and 2-(N,N-dimethyl amino)ethyl methacrylate with xanthate modified β-CD as chain transfer agent. The end group of β-CD is allowed to include 4,4'-bipyridine through host-guest inclusion to yield PDMAEMA-b-PS terminated with an inclusion complex of β-CD and bipyridine (bpy-PDMAEMA-b-PS), which is then used as surfactant to prepare emulsion droplets in toluene/water mixture. Upon addition of Ni(II), bipyridine coordinates with Ni(II) to form coordination polymers in the periphery of emulsion droplets, affording amphiphilic capsules entangled with organometallic coordination polymers, as confirmed by GPC, (1)H NMR, SEM, TEM, DLS, and so on. The organometallic coordination polymer capsules are capable of encapsulating organic cargoes. Interestingly, encapsulated cargoes can be extracted from the capsules without damaging the capsules. Such capsules are potential candidates for encapsulating and controlled release of organic cargoes.

  3. Gyroelastic fluids

    Energy Technology Data Exchange (ETDEWEB)

    Kerbel, G.D.

    1981-01-20

    A study is made of a scale model in three dimensions of a guiding center plasma within the purview of gyroelastic (also known as finite gyroradius-near theta pinch) magnetohydrodynamics. The (nonlinear) system sustains a particular symmetry called isorrhopy which permits the decoupling of fluid modes from drift modes. Isorrhopic equilibria are analyzed within the framework of geometrical optics resulting in (local) dispersion relations and ray constants. A general scheme is developed to evolve an arbitrary linear perturbation of a screwpinch equilibrium as an invertible integral transform (over the complete set of generalized eigenfunctions defined naturally by the equilibrium). Details of the structure of the function space and the associated spectra are elucidated. Features of the (global) dispersion relation owing to the presence of gyroelastic stabilization are revealed. An energy principle is developed to study the stability of the tubular screwpinch.

  4. Reduced ternary molybdenum and tungsten sulfides and hydroprocessing catalysis therewith

    Science.gov (United States)

    Hilsenbeck, S.J.; McCarley, R.E.; Schrader, G.L.; Xie, X.B.

    1999-02-16

    New amorphous molybdenum/tungsten sulfides with the general formula M{sup n+}{sub 2x/n}(L{sub 6}S{sub 8})S{sub x}, where L is molybdenum or tungsten and M is a ternary metal, has been developed. Characterization of these amorphous materials by chemical and spectroscopic methods (IR, Raman, PES) shows that the (M{sub 6}S{sub 8}){sup 0} cluster units are present. Vacuum thermolysis of the amorphous Na{sub 2x}(Mo{sub 6}S{sub 8})S{sub x}{hor_ellipsis}yMeOH first produces poorly crystalline NaMo{sub 6}S{sub 8} by disproportionation at 800 C and well-crystallized NaMo{sub 6}S{sub 8} at {>=} 900 C. Ion-exchange of the sodium material in methanol with soluble M{sup 2+} and M{sup 3+} salts (M=Sn, Co, Ni, Pb, La, Ho) produces the M{sup n+}{sub 2x/n}(Mo{sub 6}S{sub 8})S{sub x}{hor_ellipsis}yMeOH compounds. Additionally, the new reduced ternary molybdenum sulfides with the general formula M{sup n+}{sub 2x/n}Mo{sub 6}S{sub 8+x}(MeOH){sub y}[MMOS] (M=Sn, Co, Ni) is an effective hydrodesulfurization (HDS) catalyst both as-prepared and after a variety of pretreatment conditions. Under specified pretreatment conditions with flowing hydrogen gas, the SnMoS type catalyst can be stabilized, and while still amorphous, can be considered as ``Chevrel phase-like`` in that both contain Mo{sub 6}S{sub 8} cluster units. Furthermore, the small cation NiMoS and CoMoS type pretreated catalyst is shown to be very active HDS catalysts with rates that exceeded the model unpromoted and cobalt-promoted MoS{sub 2} catalysts. 9 figs.

  5. Staphylococcal α -toxin: Oligomerization of Hydrophilic Monomers to Form Amphiphilic Hexamers Induced through Contact with Deoxycholate Detergent Micelles

    Science.gov (United States)

    Bhakdi, Sucharit; Fussle, Roswitha; Tranum-Jensen, Jorgen

    1981-09-01

    Native staphylococcus aureus α -toxin is secreted as a hydrophilic polypeptide chain of Mr 34,000. The presence of deoxycholate above the critical micellar concentration induced the toxin monomers to self-associate, forming ring or cylindrical oligomers. The oligomers were amphiphilic and bound detergent. In deoxycholate solution, the protein-detergent complexes exhibited a sedimentation coefficient of 10.4 S. A Mr of 238,700 was determined by ultracentrifugation analyses at sedimentation equilibrium. Because quantitative detergent-binding studies indicated a protein/detergent ratio of approximately 5:1 (wt/wt), the protein moiety in each protein-detergent complex was determined to be approximately Mr 200 000, corresponding to a hexamer of the native molecule. The amphiphilic toxin hexamers were ultrastructurally indistinguishable from the cytolytic, annular toxin complexes that form on and in biological target membranes. They bound lipid and could be incorporated into artificial lecithin lipid vesicles. The transition of toxin protein molecules from a hydrophilic monomer to an amphiphilic oligomer through self-association has thus been shown to be inducible solely through contact of the native protein molecules with an appropriate amphiphilic substrate.

  6. STRUCTURE AND 2ND-HARMONIC GENERATION OF LANGMUIR-BLODGETT-FILMS OF 2 CHIRAL AMPHIPHILIC AZO DYES

    NARCIS (Netherlands)

    SCHOONDORP, MA; SCHOUTEN, AJ; HULSHOF, JBE; FERINGA, BL

    The properties and structure of Langmuir-Blodgett films of two new amphiphilic nonlinear optical dyes containing stereogenic (chiral) centers were studied. The dye molecule 4-[[4'-[(3R)-palmitoylpyrrolidin-1-yl]phenyl]azo]-3-nitrobenzoic acid (KZ16) forms homogeneous structures in the plane of the

  7. Amphiphilic hollow porous shell encapsulated Au@Pd bimetal nanoparticles for aerobic oxidation of alcohols in water

    KAUST Repository

    Zou, Houbing

    2015-01-01

    © The Royal Society of Chemistry 2015. This work describes the design, synthesis and analysis of an amphiphilic hollow mesoporous shell encapsulating catalytically active Au@Pd bimetal nanoparticles. The particles exhibited excellent catalytic activity and stability in the aerobic oxidation of primary and secondary alcohols to their corresponding aldehydes or ketones in water when using air as an oxidizing agent under atmospheric pressure.

  8. Polymorphism of pyridinium amphiphiles for gene delivery : Influence of ionic strength, helper lipid content, and plasmid DNA complexation

    NARCIS (Netherlands)

    Scarzello, Marco; Chupin, Vladimir; Wagenaar, Anno; Stuart, Marc C. A.; Engberts, Jan B. F. N.; Hulst, Ron

    Two double-tailed pyridinium cationic amphiphiles, differing only in the degree of unsaturation of the alkyl chains, have been selected for a detailed study of their aggregation behavior, under conditions employed for transfection experiments. The transfection efficiencies of the two molecules are

  9. Amphiphilic polymeric micelles as microreactors: improving the photocatalytic hydrogen production of the [FeFe]-hydrogenase mimic in water.

    Science.gov (United States)

    Wang, Feng; Wen, Min; Feng, Ke; Liang, Wen-Jing; Li, Xu-Bing; Chen, Bin; Tung, Chen-Ho; Wu, Li-Zhu

    2016-01-11

    An amphiphilic polymeric micelle is utilized as a microreactor to load a hydrophobic [FeFe]-hydrogenase mimic in water. The local concentration enhancement and strong interaction between the mimic and the photosensitizer as well as the water-mediated fast proton migration caused by the microreactor improve photocatalytic hydrogen production remarkably in water.

  10. Recovery and redispersion of gold nanoparticles using the self-assembly of a pH sensitive zwitterionic amphiphile.

    Science.gov (United States)

    Morita-Imura, Clara; Imura, Yoshiro; Kawai, Takeshi; Shindo, Hitoshi

    2014-11-04

    The pH-responsive self-assembly of zwitterionic amphiphile C16CA was expanded to the recovery of gold (Au) nanoparticles for environmentally friendly chemistry applications. Multilayered lamellae at pH ∼ 4 were successfully incorporated into nanoparticles by dispersion. Redispersion of nanoparticles was achieved under basic conditions by the transition of self-assembly.

  11. Triblock Copolymers with Grafted Fluorine-Free Amphiphilic Non-Ionic Side Chains for Antifouling and Fouling-Release Applications

    Energy Technology Data Exchange (ETDEWEB)

    Y Cho; H Sundaram; C Weinman; M Paik; M Dimitriou; J Finlay; M Callow; J Callow; E Kramer; C Ober

    2011-12-31

    Fluorine-free, amphiphilic, nonionic surface active block copolymers (SABCs) were synthesized through chemical modification of a polystyrene-block-poly(ethylene-ran-butylene)-block-polyisoprene triblock copolymer precursor with selected amphiphilic nonionic Brij and other surfactants. Amphiphilicity was imparted by a hydrophobic aliphatic group combined with a hydrophilic poly(ethylene glycol) (PEG) group-containing moiety. The surfaces were characterized by dynamic water contact angle, atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and near edge X-ray absorption fine structure (NEXAFS) analysis. In biofouling assays, settlement (attachment) of both spores of the green alga Ulva and cells of the diatom Navicula on SABCs modified with Brij nonionic side chains was significantly reduced relative to a PDMS standard, with a nonionic surfactant combining a PEG group and an aliphatic moiety demonstrating the best performance. Additionally, a fouling-release assay using sporelings (young plants) of Ulva and Navicula suggested that the SABC derived from nonionic Brij side chains also out-performed PDMS as a fouling-release material. Good antifouling and fouling-release properties were not demonstrated for the other two amphiphilic surfaces derived from silicone and aromatic group containing nonionic surfactants included in this study. The results suggest that small differences in chemical surface functionality impart more significant changes with respect to the antifouling settlement and fouling-release performance of materials than overall wettability behavior.

  12. Enhanced MIN-6 beta cell survival and function on a nitric oxide-releasing peptide amphiphile nanomatrix.

    Science.gov (United States)

    Lim, Dong-Jin; Andukuri, Adinarayana; Vines, Jeremy B; Rahman, Shibli M; Hwang, Patrick Tj; Kim, Jeonga; Shalev, Anath; Corbett, John A; Jun, Ho-Wook

    2014-01-01

    Innovative biomaterial strategies are required to improve islet cell retention, viability, and functionality, and thereby obtain clinically successful outcomes from pancreatic islet cell transplantation. To address this need, we have developed a peptide amphiphile-based nanomatrix that incorporates multifunctional bioactive cues and sustained release of nitric oxide. The goal of this study was to evaluate the effect of this peptide amphiphile nanomatrix on the viability and functionality of MIN-6 islet cells. Additionally, this study provides insight into the role of nitric oxide in islet cell biology, given that conventional nitric oxide donors are unable to release nitric oxide in a controlled, sustained manner, leading to ambiguous results. It was hypothesized that controlled nitric oxide release in synergy with multifunctional bioactive cues would promote islet cell viability and functionality. Nitric oxide-releasing peptide amphiphile nanomatrices within the range of 16.25 μmol to 130 μmol were used to analyze MIN-6 cell behavior. Both 32.5 μmol and 65 μmol peptide amphiphiles showed improved MIN-6 functionality in response to glucose over a 7-day time period, and the elevated functionality was correlated with both PDX-1 and insulin gene expression. Our results demonstrate that nitric oxide has a beneficial effect on MIN-6 cells in a concentration-dependent manner.

  13. In Vitro and In Vivo Efficacy of Self-Assembling RGD Peptide Amphiphiles for Targeted Delivery of Paclitaxel.

    Science.gov (United States)

    Saraf, Poonam; Li, Xiaoling; Wrischnik, Lisa; Jasti, Bhaskara

    2015-09-01

    The objective of this work was to compare the efficacy of self-assembling cyclic and linear RGD peptide amphiphiles as carriers for delivering paclitaxel to αvβ3 integrin overexpressing tumors. Linear (C18-ADA5-RGD) and cyclic (C18-ADA5-cRGDfK) peptide amphiphiles were synthesized and characterized for CMC, aggregation number and micelle stability using fluorescence spectroscopy methods. Size and morphology of micelles was studied using TEM. Fluorescence polarization and confocal microscopy assays were established to compare binding and internalization of micelles. The targeting efficacy was studied in A2058 cells using cytotoxicity assay as well as in vivo in melanoma xenograft mouse model. The linear and cyclic RGD amphiphiles exhibited CMC of 25 and 8 μM, respectively, formed nano-sized spherical micelles and showed competitive binding to αvβ3 integrin protein. FITC-loaded RGD micelles rapidly internalized into A2058 melanoma cells. Paclitaxel-loaded RGD micelles exhibited higher cytotoxicity compared with free drug in A2058 cells in vitro as well as in vivo. Cyclic RGD micelles exhibited better targeting efficacy but were less effective compared to linear RGD micelles as drug delivery vehicle due to lower drug solubilization capacity and lesser kinetic stability. Results from the study proved the effectiveness of self-assembling low molecular weight RGD amphiphiles as carriers for targeted delivery of paclitaxel.

  14. Amphiphilic copolymers based on PEG-acrylate as surface active water viscosifiers : Towards new potential systems for enhanced oil recovery

    NARCIS (Netherlands)

    Raffa, Patrizio; Broekhuis, Antonius A.; Picchioni, Francesco

    2016-01-01

    With the purpose of investigating new potential candidates for enhanced oil recovery (EOR), amphiphilic copolymers based on Poly(ethylene glycol) methyl ether acrylate (PEGA) have been prepared by Atom Transfer Radical Polymerization (ATRP). A P(PEGA) homopolymer, a block copolymer with styrene

  15. Biocatalysis of immobilized chlorophyllase in a ternary micellar system.

    Science.gov (United States)

    Gaffar, R; Kermasha, S; Bisakowski, B

    1999-09-24

    The immobilization of chlorophyllase was optimized by physical adsorption on various inorganic supports, including alumina, celite, Dowex-1-chloride, glass beads and silica gel. The enzyme was also immobilized in different media, including water, Tris-HCl buffer solution and a ternary micellar system containing Tris-HCl buffer solution, hexane and surfactant. The highest immobilization efficiency (84.56%) and specific activity (0.34 mumol hydrolyzed chlorophyll mg protein-1 per min) were obtained when chlorophyllase was suspended in Tris-HCl buffer solution and adsorbed onto silica gel. The effect of different ratios of chlorophyllase to the support and the optimum incubation time for the immobilization of chlorophyllase were determined to be 1-4 and 60 min, respectively. The experimental results showed that the optimum pH and temperature for the immobilized chlorophyllase were 8.0 and 35 degrees C, respectively. The use of optimized amounts of selected membrane lipids increased the specific activity of the immobilized chlorophyllase by approximately 50%. The enzyme kinetic studies indicated that the immobilized chlorophyllase showed a higher affinity towards chlorophyll than pheophytin as substrate.

  16. Contribution to the aluminum–tin–zinc ternary system

    Science.gov (United States)

    Drápala, J.; Kostiuková, G.; Losertová, M.

    2017-11-01

    The Sn–Zn–Al alloys are one of significant candidates in the proposal of alternative lead-free solders for higher temperature soldering. This paper deals with the study of the aluminum–tin–zinc system. Twenty Sn–Zn–Al alloys together with six binary Sn–Zn alloys were prepared and studied experimentally. Alloys were prepared from pure Sn, Zn and Al (melting and cooling in a vacuum resistance furnace). The specimens were studied metallographically including the micro-hardness measurements, complete chemical analysis (ICP-AES, OES), X-ray micro-analysis of alloys by SEM and EDX in order to determine the composition and identification of individual phases. Significant temperatures and enthalpies of phase transformations were determined by DTA. After long-term annealing of selected alloys in vacuum followed by quenching the structural and chemical microanalyses of the present phases and their limit concentrations were carried out. The achieved results were compared with the thermodynamic modelling of the ternary Sn–Zn–Al system (computer programs THERMOCALC, MTDATA, PANDAT and databases CALPHAD, COST). Electrical resistivity, density, magnetic susceptibility and wettability of Sn–Zn–Al solders were measured as well.

  17. Dynamical simulation of sputtering and reflection from a ternary alloy

    Science.gov (United States)

    Ishida, M.; Yamaguchi, Y.; Yoshinaga, H.; Yamamura, Y.

    The sputtering and the reflection from a Tb0.2Fe0.7Co0.1 alloy due to Ar+ ion bombardment have been investigated by the Monte Carlo simulation code ACAT-DIFFUSE which include the compositional change induced by ion influence. In the Tb-Fe-Co system, Fe atoms are preferentially sputtered. The atomic size of a Tb atom is the largest of these three atoms, and so Tb atoms trap preferentially in vacancies. The steady-state concentration of Tb atoms at the topmost layer is larger than the bulk concentration for the low energy ions due to radiation-induced segregation and preferential sputtering of Fe atoms. As the ion fluence increases, the atomic fractions of sputtered atoms calculated by the ACAT-DIFFUSE code become those of the bulk concentration. The depth profiles of each element at the steady state depend on the incident energy. The total sputtering yield and the reflection coefficient from a Tb-Fe-Co alloy calculated by the ACAT-DIFFUSE code are larger than those by the ACAT code at near-threshold energies, where the ACAT code does not include the ion-influence effect. The energy spectra of back-scattered Ar atoms from the present ternary alloy have very similar profiles to those from a monoatomic Tb target, especially for low-energy Ar+ ions.

  18. Iron binary and ternary coatings with molybdenum and tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Yar-Mukhamedova, Gulmira, E-mail: gulmira-alma-ata@mail.ru [Institute Experimental and Theoretical Physics Al-Farabi Kazakh National University, 050038, Al-Farabi av., 71, Almaty (Kazakhstan); Ved, Maryna; Sakhnenko, Nikolay; Karakurkchi, Anna; Yermolenko, Iryna [National Technical University “Kharkov Polytechnic Institute”, Kharkov (Ukraine)

    2016-10-15

    Highlights: • High quality coatings of double Fe-Mo and ternary Fe-Mo-W electrolytic alloys can be produced both in a dc and a pulsed mode. • Application of unipolar pulsed current allows receiving an increased content of the alloying components and their more uniform distribution over the surface. • It is established that Fe-Mo and Fe-Mo-W coatings have an amorphous structure and exhibit improved corrosion resistance and microhardness as compared with the steel substrate due to the inclusion molybdenum and tungsten. - Abstract: Electrodeposition of Fe-Mo-W and Fe-Mo layers from a citrate solution containing iron(III) on steel and iron substrates is compared. The utilization of iron(III) compounds significantly improved the electrolyte stability eliminating side anodic redox reactions. The influence of concentration ratios and electrodeposition mode on quality, chemical composition, and functional properties of the alloys is determined. It has been found that alloys deposited in pulse mode have more uniform surface morphology and chemical composition and contain less impurities. Improvement in physical and mechanical properties as well as corrosion resistance of Fe-Mo and Fe-Mo-W deposits when compared with main alloy forming metals is driven by alloying components chemical passivity as well as by alloys amorphous structure. Indicated deposits can be considered promising materials in surface hardening technologies and repair of worn out items.

  19. Delay Insensitive Ternary CMOS Logic for Secure Hardware

    Directory of Open Access Journals (Sweden)

    Ravi S. P. Nair

    2015-09-01

    Full Text Available As digital circuit design continues to evolve due to progress of semiconductor processes well into the sub 100 nm range, clocked architectures face limitations in a number of cases where clockless asynchronous architectures generate less noise and produce less electro-magnetic interference (EMI. This paper develops the Delay-Insensitive Ternary Logic (DITL asynchronous design paradigm that combines design aspects of similar dual-rail asynchronous paradigms and Boolean logic to create a single wire per bit, three voltage signaling and logic scheme. DITL is compared with other delay insensitive paradigms, such as Pre-Charge Half-Buffers (PCHB and NULL Convention Logic (NCL on which it is based. An application of DITL is discussed in designing secure digital circuits resistant to side channel attacks based on measurement of timing, power, and EMI signatures. A Secure DITL Adder circuit is designed at the transistor level, and several variance parameters are measured to validate the efficiency of DITL in resisting side channel attacks. The DITL design methodology is then applied to design a secure 8051 ALU.

  20. Multistate Memristive Tantalum Oxide Devices for Ternary Arithmetic

    Science.gov (United States)

    Kim, Wonjoo; Chattopadhyay, Anupam; Siemon, Anne; Linn, Eike; Waser, Rainer; Rana, Vikas

    2016-11-01

    Redox-based resistive switching random access memory (ReRAM) offers excellent properties to implement future non-volatile memory arrays. Recently, the capability of two-state ReRAMs to implement Boolean logic functionality gained wide interest. Here, we report on seven-states Tantalum Oxide Devices, which enable the realization of an intrinsic modular arithmetic using a ternary number system. Modular arithmetic, a fundamental system for operating on numbers within the limit of a modulus, is known to mathematicians since the days of Euclid and finds applications in diverse areas ranging from e-commerce to musical notations. We demonstrate that multistate devices not only reduce the storage area consumption drastically, but also enable novel in-memory operations, such as computing using high-radix number systems, which could not be implemented using two-state devices. The use of high radix number system reduces the computational complexity by reducing the number of needed digits. Thus the number of calculation operations in an addition and the number of logic devices can be reduced.

  1. Alloy multilayers and ternary nanostructures by direct-write approach

    Science.gov (United States)

    Porrati, F.; Sachser, R.; Gazzadi, G. C.; Frabboni, S.; Terfort, A.; Huth, M.

    2017-10-01

    The fabrication of nanopatterned multilayers, as used in optical and magnetic applications, is usually achieved by two independent steps, which consist in the preparation of multilayer films and in the successive patterning by means of lithography and etching processes. Here we show that multilayer nanostructures can be fabricated by using focused electron beam induced deposition (FEBID), which allows the direct writing of nanostructures of any desired shape with nanoscale resolution. In particular, {[{{{Co}}}2{{Fe}}/{{Si}}]}n multilayers are prepared by the alternating deposition from the metal carbonyl precursors, {{{HFeCo}}}3{({{CO}})}12 and {{Fe}}{({{CO}})}5, and neopentasilane, {{{Si}}}5{{{H}}}12. The ability to fabricate nanopatterned multilayers by FEBID is of interest for the realization of hyperbolic metamaterials and related nanodevices. In a second experiment, we treated the multilayers by low-energy electron irradiation in order to induce atomic species intermixing with the purpose to obtain ternary nanostructured compounds. Transmission electron microscopy and electrical transport measurements indicate that in thick multilayers, (n = 12), the intermixing is only partial, taking place mainly in the upper part of the structures. However, for thin multilayers, (n = 2), the intermixing is such that a transformation into the L21 phase of the Co2FeSi Heusler compound takes place over the whole sample volume.

  2. The role of In in III-nitride ternary semiconductors

    CERN Multimedia

    Redondo cubero, A

    This proposal aims to study the role of In in the outstanding efficiency of luminescent devices based on group III-nitride ternary semiconductors. To study the microscopic environments of In in GaInN and AlInN, Perturbed Angular Correlation (PAC) experiments will be performed using the PAC-probes $^{111m}$Cd($^{111}$Cd), $^{115}$Cd($^{115}$In) and $^{117}$Cd($^{117}$In). Temperature dependent PAC measurements using the $^{111}$In($^{111}$Cd) probe indicated that In in GaN and AlN forms a complex with a defect, possibly a nitrogen vacancy (V$_{N}$), which is stable up to high temperatures and might be involved in the luminescence mechanisms. Analysing these results two questions arose: \\\\ \\\\1. Does the fact that the actual measurement is performed with the daughter nucleus $^{111}$Cd (being an acceptor) influence the probe-defect interaction? This question can be answered by performing measurements with the complementary probe $^{117}$Cd($^{117}$In). \\\\ \\\\ 2. What is the significance of $\\textit{a...

  3. Control mechanism of double-rotator-structure ternary optical computer

    Science.gov (United States)

    Kai, SONG; Liping, YAN

    2017-03-01

    Double-rotator-structure ternary optical processor (DRSTOP) has two characteristics, namely, giant data-bits parallel computing and reconfigurable processor, which can handle thousands of data bits in parallel, and can run much faster than computers and other optical computer systems so far. In order to put DRSTOP into practical application, this paper established a series of methods, namely, task classification method, data-bits allocation method, control information generation method, control information formatting and sending method, and decoded results obtaining method and so on. These methods form the control mechanism of DRSTOP. This control mechanism makes DRSTOP become an automated computing platform. Compared with the traditional calculation tools, DRSTOP computing platform can ease the contradiction between high energy consumption and big data computing due to greatly reducing the cost of communications and I/O. Finally, the paper designed a set of experiments for DRSTOP control mechanism to verify its feasibility and correctness. Experimental results showed that the control mechanism is correct, feasible and efficient.

  4. Internal oxidation of laminated ternary Ru-Ta-Zr coatings

    Science.gov (United States)

    Chen, Yung-I.; Lu, Tso-Shen

    2015-10-01

    Researchers have observed the internal oxidation phenomenon in binary alloy coatings when developing refractory alloy coatings for protective purposes by conducting annealing at high temperatures and in oxygen-containing atmospheres. The coatings were assembled using cyclical gradient concentration deposition during cosputtering by employing a substrate holder rotating at a slow speed. The internally oxidized zone demonstrated a laminated structure, comprising alternating oxygen-rich and oxygen-deficient layers stacked in a general orientation. In the current study, Ru-Ta-Zr coatings were prepared with various stacking sequences during cosputtering. The Ru-Ta-Zr coatings were annealed at 600 °C in an atmosphere continuously purged with 1% O2-99% Ar mixed gas for 30 min. A transmission electron microscope was used to examine the periods of the laminated layers and crystallinity of the annealed coatings. Depth profiles produced using an Auger electron spectroscope and X-ray photoelectron spectroscope were used to certify the periodic variation of the related constituents and chemical states of the elements, respectively. The results indicate that the internally oxidized ternary coatings are stacked of Ru-, Ta2O5-, and ZrO2-dominant sublayers and that the stacking sequences of the sublayers affect the crystalline structure of the coatings. Zr is oxidized preferentially in the Ru-Ta-Zr coatings, increasing the surface hardness of the oxidized coatings.

  5. Growth Mechanism of Nanowires: Binary and Ternary Chalcogenides

    Science.gov (United States)

    Singh, N. B.; Coriell, S. R.; Su, Ching-Hua; Hopkins, R. H.; Arnold, B.; Choa, Fow-Sen; Cullum, Brian

    2016-01-01

    Semiconductor nanowires exhibit very exciting optical and electrical properties including high transparency and a several order of magnitude better photocurrent than thin film and bulk materials. We present here the mechanism of nanowire growth from the melt-liquid-vapor medium. We describe preliminary results of binary and ternary selenide materials in light of recent theories. Experiments were performed with lead selenide and thallium arsenic selenide systems which are multifunctional material and have been used for detectors, acousto-optical, nonlinear and radiation detection applications. We observed that small units of nanocubes and elongated nanoparticles arrange and rearrange at moderate melt undercooling to form the building block of a nanowire. Since we avoided the catalyst, we observed self-nucleation and uncontrolled growth of wires from different places. Growth of lead selenide nanowires was performed by physical vapor transport method and thallium arsenic selenide nanowire by vapor-liquid-solid (VLS) method. In some cases very long wires (>mm) are formed. To achieve this goal experiments were performed to create situation where nanowires grew on the surface of solid thallium arsenic selenide itself.

  6. Thermophysical Properties of Fluids and Fluid Mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Sengers, Jan V.; Anisimov, Mikhail A.

    2004-05-03

    The major goal of the project was to study the effect of critical fluctuations on the thermophysical properties and phase behavior of fluids and fluid mixtures. Long-range fluctuations appear because of the presence of critical phase transitions. A global theory of critical fluctuations was developed and applied to represent thermodynamic properties and transport properties of molecular fluids and fluid mixtures. In the second phase of the project, the theory was extended to deal with critical fluctuations in complex fluids such as polymer solutions and electrolyte solutions. The theoretical predictions have been confirmed by computer simulations and by light-scattering experiments. Fluctuations in fluids in nonequilibrium states have also been investigated.

  7. Automatic fluid dispenser

    Science.gov (United States)

    Sakellaris, P. C. (Inventor)

    1977-01-01

    Fluid automatically flows to individual dispensing units at predetermined times from a fluid supply and is available only for a predetermined interval of time after which an automatic control causes the fluid to drain from the individual dispensing units. Fluid deprivation continues until the beginning of a new cycle when the fluid is once again automatically made available at the individual dispensing units.

  8. Amphiphilic triblock copolymers with PEGylated hydrocarbon structures as environmentally friendly marine antifouling and fouling-release coatings.

    Science.gov (United States)

    Zhou, Zhaoli; Calabrese, David R; Taylor, Warren; Finlay, John A; Callow, Maureen E; Callow, James A; Fischer, Daniel; Kramer, Edward J; Ober, Christopher K

    2014-01-01

    The ideal marine antifouling (AF)/fouling-release (FR) coating should be non-toxic, while effectively either resisting the attachment of marine organisms (AF) or significantly reducing their strength of attachment (FR). Many recent studies have shown that amphiphilic polymeric materials provide a promising solution to producing such coatings due to their surface dual functionality. In this work, poly(ethylene glycol) (PEG) of different molecular weights (Mw = 350, 550) was coupled to a saturated difunctional alkyl alcohol to generate amphiphilic surfactants (PEG-hydrocarbon-OH). The resulting macromolecules were then used as side chains to covalently modify a pre-synthesized PS8 K-b-P(E/B)25 K-b-PI10 K (SEBI or K3) triblock copolymer, and the final polymers were applied to glass substrata through an established multilayer surface coating technique to prepare fouling resistant coatings. The coated surfaces were characterized with AFM, XPS and NEXAFS, and evaluated in laboratory assays with two important fouling algae, Ulva linza (a green macroalga) and Navicula incerta, a biofilm-forming diatom. The results suggest that these polymer-coated surfaces undergo surface reconstruction upon changing the contact medium (polymer/air vs polymer/water), due to the preferential interfacial aggregation of the PEG segment on the surface in water. The amphiphilic polymer-coated surfaces showed promising results as both AF and FR coatings. The sample with longer PEG chain lengths (Mw = 550 g mol(-1)) exhibited excellent properties against both algae, highlighting the importance of the chemical structures on ultimate biological performance. Besides reporting synthesis and characterization of this new type of amphiphilic surface material, this work also provides insight into the nature of PEG/hydrocarbon amphiphilic coatings, and this understanding may help in the design of future generations of fluorine-free, environmentally friendly AF/FR polymeric coatings.

  9. Gadolinium-Functionalized Peptide Amphiphile Micelles for Multimodal Imaging of Atherosclerotic Lesions.

    Science.gov (United States)

    Yoo, Sang Pil; Pineda, Federico; Barrett, John C; Poon, Christopher; Tirrell, Matthew; Chung, Eun Ji

    2016-11-30

    The leading causes of morbidity and mortality globally are cardiovascular diseases, and nanomedicine can provide many improvements including disease-specific targeting, early detection, and local delivery of diagnostic agents. To this end, we designed fibrin-binding, peptide amphiphile micelles (PAMs), achieved by incorporating the targeting peptide cysteine-arginine-glutamic acid-lysine-alanine (CREKA), with two types of amphiphilic molecules containing the gadoliniuim (Gd) chelator diethylenetriaminepentaacetic acid (DTPA), DTPA-bis(stearylamide)(Gd), and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[(poly(ethylene glycol) (PEG))-2000]-DTPA(Gd) (DSPE-PEG2000-DTPA(Gd)). The material characteristics of the resulting nanoparticle diagnostic probes, clot-binding properties in vitro, and contrast enhancement and safety for dual, optical imaging-magnetic resonance imaging (MRI) were evaluated in the atherosclerotic mouse model. Transmission electron micrographs showed a homogenous population of spherical micelles for formulations containing DSPE-PEG2000-DTPA(Gd), whereas both spherical and cylindrical micelles were formed upon mixing DTPA-BSA(Gd) and CREKA amphiphiles. Clot-binding assays confirmed DSPE-PEG2000-DTPA(Gd)-based CREKA micelles targeted clots over 8-fold higher than nontargeting (NT) counterpart micelles, whereas no difference was found between CREKA and NT, DTPA-BSA(Gd) micelles. However, in vivo MRI and optical imaging studies of the aortas and hearts showed fibrin specificity was conferred by the peptide ligand without much difference between the nanoparticle formulations or shapes. Biodistribution studies confirmed that all micelles were cleared through both the reticuloendothelial system and renal clearance, and histology showed no signs of necrosis. In summary, these studies demonstrate the successful synthesis, and the molecular imaging capabilities of two types of CREKA-Gd PAMs for atherosclerosis. Moreover, we demonstrate the differences in

  10. Hydrophobic cotton textile surfaces using an amphiphilic graphene oxide (GO) coating

    Energy Technology Data Exchange (ETDEWEB)

    Tissera, Nadeeka D., E-mail: nadeekat@slintec.lk; Wijesena, Ruchira N.; Perera, J. Rangana; Nalin de Silva, K.M.; Amaratunge, Gehan A.J.

    2015-01-01

    Graphical abstract: - Highlights: • Different GO dispersions were prepared by sonicating different amounts of GO in water. Degree of exfoliation of these GO sheets in water was analyzed using Atomic Force Microscopy (AFM). • AFM results obtained showed higher the GO concentration on water more the size of GO sheets and lesser the degree of exfoliation. • GO with different amounts was deposited on cotton fabric using simple dyeing method. • High GO loading on cotton increase the surface area coverage of the textile fibers with GO sheets. This led to less edge to mid area ratio of grafted GO sheets. • As contribution of mid area of GO increase on fiber surface cotton fabric becomes more hydrophobic. • Amphiphilic property of GO sheets was used to lower the surface energy of the cotton fibers leading to hydrophobic property. - Abstract: We report for the first time hydrophobic properties on cotton fabric successfully achieved by grafting graphene oxide on the fabric surface, using a dyeing method. Graphite oxide synthesized by oxidizing natural flake graphite employing improved Hummer's method showed an inter layer spacing of ∼1 nm from XRD. Synthesized graphite oxide was exfoliated in water using ultrasound energy to obtain graphene oxide (GO). AFM data obtained for the graphene oxide dispersed in an aqueous medium revealed a non-uniform size distribution. FTIR characterization of the synthesized GO sheets showed both hydrophilic and hydrophobic functional groups present on the nano sheets giving them an amphiphilic property. GO flakes of different sizes were successfully grafted on to a cotton fabric surface using a dip dry method. Loading different amounts of graphene oxide on the cotton fiber surface allowed the fabric to demonstrate different degrees of hydrophobicity. The highest observed water contact angle was at 143° with the highest loading of graphene oxide. The fabric surfaces grafted with GO also exhibits adhesive type hydrophobicity

  11. Synovial fluid analysis

    Science.gov (United States)

    Joint fluid analysis; Joint fluid aspiration ... El-Gabalawy HS. Synovial fluid analysis, synovial biopsy, and synovial pathology. In: Firestein GS, Budd RC, Gabriel SE, McInnes IB, O'Dell JR, eds. Kelly's Textbook of ...

  12. Ternary particles for effective vaccine delivery to the pulmonary system

    Science.gov (United States)

    Terry, Treniece La'shay

    Progress in the fields of molecular biology and genomics has provided great insight into the pathogenesis of disease and the defense mechanisms of the immune system. This knowledge has lead to the classification of an array of abnormal genes, for which, treatment relies on cellular expression of proteins. The utility of DNA-based vaccines hold great promise for the treatment of genetically based and infectious diseases, which ranges from hemophilia, cystic fibrosis, and HIV. Synthetic delivery systems consisting of cationic polymers, such as polyethylenimine (PEI), are capable of condensing DNA into compact structures, maximizing cellular uptake of DNA and yielding high levels of protein expression. To date, short term expression is a major obstacle in the development of gene therapies and has halted their expansion in clinical applications. This study intends to develop a sustained release vaccine delivery system using PLA-PEG block copolymers encapsulating PEI:DNA polyplexes. To enhance the effectiveness of such DNA-based vaccines, resident antigen presenting cells, macrophages and dendritic cells, will be targeted within the alveoli regions of the lungs. Porous microspheres will be engineered with aerodynamic properties capable of achieving deep lung deposition. A fabrication technique using concentric nozzles will be developed to produce porous microspheres. It was observed that modifications in the dispersed to continuous phase ratios have the largest influence on particle size distributions, release rates and encapsulation efficiency which ranged form 80--95% with fourteen days of release. Amphiphilic block copolymers were also used to fabricate porous microspheres. The confirmation of PEG within the biodegradable polymer backbone was found to have a tremendous impact on the microsphere morphology and encapsulation efficiency which varied from 50--90%. Porous microspheres were capable of providing sustained gene expression when tested in vitro using the

  13. Impact of ionizing radiation on physicochemical and biological properties of an amphiphilic macromolecule.

    Science.gov (United States)

    Gu, Li; Zablocki, Kyle; Lavelle, Linda; Bodnar, Stanko; Halperin, Frederick; Harper, Ike; Moghe, Prabhas V; Uhrich, Kathryn E

    2012-09-01

    An amphiphilic macromolecule (AM) was exposed to ionizing radiation (both electron beam and gamma) at doses of 25 kGy and 50 kGy to study the impact of these sterilization methods on the physicochemical properties and bioactivity of the AM. Proton nuclear magnetic resonance and gel permeation chromatography were used to determine the chemical structure and molecular weight, respectively. Size and zeta potential of the micelles formed from AMs in aqueous media were evaluated by dynamic light scattering. Bioactivity of irradiated AMs was evaluated by measuring inhibition of oxidized low-density lipoprotein uptake in macrophages. From these studies, no significant changes in the physicochemical properties or bioactivity were observed after the irradiation, demonstrating that the AMs can withstand typical radiation doses used to sterilize materials.

  14. Amphiphilic Ditopic Bis-Aqua Gd-AAZTA-like Complexes Enhance Relaxivity of Lipidic MRI Nanoprobes.

    Science.gov (United States)

    Gambino, Giuseppe; Tei, Lorenzo; Carniato, Fabio; Botta, Mauro

    2016-08-05

    Two amphiphilic mono- and dimeric GdAAZTA-like chelates composed of stable bis-aquo Gd(III) complexes (q=2) linked to one (for the monomer) or two dodecyl aliphatic chains (for the dimer) were synthesized. Both chelates showed high relaxivity when incorporated into the lipid bilayer of liposomes or after interaction with human serum albumin (HSA). The ditopic complex shows a significantly decreased internal motion relative to the monomeric complex, associated with an enhanced relaxivity (r1 ≈60 mm(-1)  s(-1) , at 30 MHz and 310 K). The presence of two metal-bound water molecules in fast exchange and the restricted rotational freedom make the relaxivity of this system the highest measured for paramagnetic liposomes. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Salt Effect on the Cloud Point Phenomenon of Amphiphilic Drug-Hydroxypropylmethyl Cellulose System

    Directory of Open Access Journals (Sweden)

    Mohd. Sajid Ali

    2014-01-01

    Full Text Available Effect of two amphiphilic drugs (tricyclic antidepressant, nortriptyline hydrochloride (NORT, and nonsteroidal anti-inflammatory drug, sodium salt of ibuprofen (IBF on the cloud point of biopolymer hydroxypropylmethyl cellulose (HPMC was studied. Effect of NaCl was also seen on the CP of HPMC-drug system. CP of HPMC increases uniformly on increasing the (drug. Both drugs, though one being anionic (IBF and other cationic (NORT, affect the CP in almost the same manner but with different extent implying the role of hydrophobicity in the interaction between drug and polymer. Salt affects the CP of the drug in a dramatic way as low concentration of salt was only able to increase the value of the CP, though not affecting the pattern. However, in presence of high concentration of salts, minimum was observed on CP versus (drug plots. Various thermodynamic parameters were evaluated and discussed on the basis of the observed results.

  16. Single-component solid lipid nanocarriers prepared with ultra-long chain amphiphilic lipids

    DEFF Research Database (Denmark)

    Wei, Wei; Lu, Xiaonan; Wang, Zegao

    2017-01-01

    HYPOTHESIS: Synthetic sugar alcohol mono-behenates with high melting points, surface activity and resistance to enzymatic lipolysis, are expected to form stable single-component solid lipid nanocarriers (SC-SLNs). The preparation methods and the polar head group of the molecules should affect...... the smallest mean size (∼100nm with PdI of 0.26). In addition, they displayed high entrapment efficiency of fenofibrate (95%) and long term drug release. Nanocarriers prepared by emulsification-diffusion method entrapped fenofibrate into lipid bilayers. In contrast, Nanocarriers prepared by melting......-probe sonication method had a micelle structure with fenofibrate incorporated into a lipid monolayer. This study provides an insight into the systematic development of novel amphiphilic lipids for solid lipid-based drug delivery system....

  17. Accessible Mannitol-Based Amphiphiles (MNAs) for Membrane Protein Solubilisation and Stabilisation

    DEFF Research Database (Denmark)

    Hussain, Hazrat; Du, Yang; Scull, Nicola J.

    2016-01-01

    -solubilised membrane proteins often denature and aggregate, resulting in loss of both structure and function. In this study, a novel class of agents, designated mannitol-based amphiphiles (MNAs), were prepared and characterised for their ability to solubilise and stabilise membrane proteins. Some of MNAs conferred......Integral membrane proteins are amphipathic molecules crucial for all cellular life. The structural study of these macromolecules starts with protein extraction from the native membranes, followed by purification and crystallisation. Detergents are essential tools for these processes, but detergent...... enhanced stability to four membrane proteins including a G protein-coupled receptor (GPCR), the β2 adrenergic receptor (β2AR), compared to both n-dodecyl-d-maltoside (DDM) and the other MNAs. These agents were also better than DDM for electron microscopy analysis of the β2AR. The ease of preparation...

  18. New penta-saccharide-bearing tripod amphiphiles for membrane protein structure studies

    DEFF Research Database (Denmark)

    Ehsan, Muhammad; Ghani, Lubna; Du, Yang

    2017-01-01

    of detergents, are available, purification and structural characterization of many membrane proteins remain challenging. In the current study, a new class of tripod amphiphiles bearing two different penta-saccharide head groups, designated TPSs, were developed and evaluated for their ability to extract...... and stabilize a range of diverse membrane proteins. Variations in the structures of the detergent head and tail groups allowed us to prepare three sets of the novel agents with distinctive structures. Some TPSs (TPS-A8 and TPS-E7) were efficient at extracting two proteins in a functional state while others (TPS......Integral membrane proteins either alone or as complexes carry out a range of key cellular functions. Detergents are indispensable tools in the isolation of membrane proteins from biological membranes for downstream studies. Although a large number of techniques and tools, including a wide variety...

  19. The Osteogenic Differentiation Effect of the FN Type 10-Peptide Amphiphile on PCL Fiber

    Directory of Open Access Journals (Sweden)

    Ye-Rang Yun

    2018-01-01

    Full Text Available The fibronectin type 10-peptide amphiphile (FNIII10-PA was previously genetically engineered and showed osteogenic differentiation activity on rat bone marrow stem cells (rBMSCs. In this study, we investigated whether FNIII10-PA demonstrated cellular activity on polycaprolactone (PCL fibers. FNIII10-PA significantly increased protein production and cell adhesion activity on PCL fibers in a dose-dependent manner. In cell proliferation results, there was no effect on cell proliferation activity by FNIII10-PA; however, FNIII10-PA induced the osteogenic differentiation of MC3T3-E1 cells via upregulation of bone sialoprotein (BSP, collagen type I (Col I, osteocalcin (OC, osteopontin (OPN, and runt-related transcription factor 2 (Runx2 mitochondrial RNA (mRNA levels; it did not increase the alkaline phosphatase (ALP mRNA level. These results indicate that FNIII10-PA has potential as a new biomaterial for bone tissue engineering applications.

  20. Synthesis, Amphiphilic Property and Thermal Stability of Novel Main-chain Poly(o-carborane-benzoxazines)

    Science.gov (United States)

    Yang, Xiaoxue; Han, Guo; Yang, Zhen; Zhang, Xiaoa; Jiang, Shengling; Lyu, Yafei

    2017-10-01

    Five poly(o-carborane-benzoxazines) were synthesized via Mannich reaction of o-carborane bisphenol, paraformaldehyde, and diamine, and their structures were well characterized. Light transmission and 1H NMR in D2O confirmed that poly(o-carborane-benzoxazines) with PEG segments showed excellent water solubility and amphiphilic property. TGA analyses were conducted under nitrogen and air, and the results showed that the polymers own high initial decomposition temperatures owing to the shielding effect of carborane moiety on its adjacent aromatic structures. Besides, poly(o-carborane-benzoxazines) own high char yield at elevated temperatures, for the boron atom could combine with oxygen from the polymer structure or/and the air and be oxidized to form boron oxide, and thus the polymer weight is retained to a large extent. PEG segments had an adverse effect on the initial decomposition and char yield, and thus their concentration should be adjusted to control the polymer’s thermal stability.

  1. Amphiphilic conetworks and gels physically cross-linked via stereocomplexation of polylactide.

    Science.gov (United States)

    Fan, Xiaoshan; Wang, Mian; Yuan, Du; He, Chaobin

    2013-11-19

    Amphiphilic conetworks (APCNs), consisting of hydrophilic poly[poly(ethylene glycol) methyl ester acrylate] (PPEGMEA) and hydrophobic stereocomplex of poly(L-lactide) (PLLA) and poly(D-lactide) (PDLA), were prepared by free radical copolymerization of PEGMEA with acrylate macromonomer of the PLA stereocomplex. The effects of stereocomplexation and the amount of PLA stereocomplex on the rheology properties of APCNs were investigated. The results indicated that the APCNs was stronger in the presence of stereocomplexation compared with the that of nonstereocomplex system, and the strength of the APCNs increased with the increasing of the amount of PLA stereocomplex. The storage modulus of the APCNs could be easily tuned from 1200 to 4300 Pa by incorporating 2-10% of stereocomplex PLA. On the other hand, the swelling behavior of APCNs decreased with the increasing content of hydrophobic PLA cross-linker.

  2. Vesicle-to-micelle transition in aqueous solutions of amphiphilic calixarene derivatives

    Science.gov (United States)

    Micali, Norberto; Villari, Valentina; Consoli, Grazia M. L.; Cunsolo, Francesca; Geraci, Corrada

    2006-05-01

    Structure and conformation of spontaneous self-assembled calix[8]arenes derivatives are studied by means of static and dynamic light scattering and electrophoretic mobility. These amphiphilic molecules are in the aggregated form in aqueous solution, in a wide range of pH ; they take a vesicle structure in neutral and basic pH environment, but, in relatively strong acidic conditions (below pH=4.5 ), a transition from vesicle to micelle occurs. The structural change is driven by the surface charge density. At neutral pH calix[8]arenes take a negative surface charge, which prevents coagulation and ensures stability; at acidic pH the surface charge tend to become positive because of the protonation of the hydrophilic head. These pH -responsive aggregates, able to release an encapsulated hydrophilic guest, are promising systems for application as nanocarriers.

  3. Synthesis of amphiphilic diblock copolymer for surface modification of Ethylene-Norbornene copolymers

    DEFF Research Database (Denmark)

    Levinsen, Simon; Svendsen, Winnie Edith; Horsewell, Andy

    2014-01-01

    consisting of a bulk material compatible block and a hydrophilic block. To utilize the possibility of incorporating diblock copolymers into ethylenenorbornene copolymers, we have in this work developed a model poly(ethylene-1-butene) polymer compatible with the commercial available ethylene......-norbornene copolymer TOPAS. Through matching of the radius of gyration for the model polymer and TOPAS the miscibility was achieved. The poly(ethylene-1-butene) polymer was synthesized from a hydrogenated anionic polymerized polybutadiene polymer. As hydrophilic block poly(ethylene oxide) was subsequently added also......The aim of this work is to produce polymer modifiers in order to develop hydrophilic polymeric surfaces for use in microfluidics. The use of hydrophilic polymers in microfluidics will have many advantages e.g. preventing protein absorbance. Here we present an amphiphilic diblock copolymer...

  4. Novel fluorescent amphiphilic block copolymers: photophysics behavior and interactions with DNA

    Directory of Open Access Journals (Sweden)

    2007-06-01

    Full Text Available In this study, novel amphiphilic fluorescent copolymers poly(N-vinylpyrrolidone-b-poly(N-methacryloyl-N'-(α-naphthylthiourea (PVP-b-PNT were synthesized via ATRP with poly(N-vinylpyrrolidone-Cl as macroinitiator and N-methacryloyl-N'-α-naphthylthiourea (NT as hydrophobic segment. PVP-b-PNT copolymers were characterized by 1H NMR, GPC-MALLS and fluorescence measurements. The aggregation behavior of PVP-b-PNT in water was investigated by transmission electron microscope (TEM and dynamic light scattering (DLS measurement. The photophysics behavior of PVP-b-PNT showed that block copolymer formed strong excimer. The interaction of DNA with the block copolymer made the excimer of block copolymer quench. The cytotoxicity result of PVP-b-PNT in cell culture in vitro indicated that this copolymer PVP-b-PNT had good biocompatibility.

  5. Tunable amphiphilicity and multifunctional applications of ionic-liquid-modified carbon quantum dots.

    Science.gov (United States)

    Wang, Baogang; Song, Aixin; Feng, Lei; Ruan, Hong; Li, Hongguang; Dong, Shuli; Hao, Jingcheng

    2015-04-01

    During the past decade, increasing attention has been paid to photoluminescent nanocarbon materials, namely, carbon quantum dots (CQDs). It is gradually accepted that surface engineering plays a key role in regulating the properties and hence the applications of the CQDs. In this paper, we prepared highly charged CQDs through a one-pot pyrolysis with citric acid as carbon source and a room-temperature imidazolium-based ionic liquid as capping agent. The as-prepared CQDs exhibit high quantum yields up to 25.1% and are stable under various environments. In addition, the amphiphilicity of the CQDs can be facilely tuned by anion exchange, which leads to a spontaneous phase transfer between water and oil phase. The promising applications of the CQDs as ion sensors and fluorescent inks have been demonstrated. In both cases, these ionic-liquid-modified CQDs were found to possess novel characteristics and/or superior functions compared to existing ones.

  6. Amphiphilic poly(p-phenylene)-driven multiscale assembly of fullerenes to nanowhiskers.

    Science.gov (United States)

    Nurmawati, Muhammad Hanafiah; Ajikumar, Parayil Kumaran; Renu, Ravindranath; Sow, Chorng Haur; Valiyaveettil, Suresh

    2008-07-01

    Molecular level alignment of components and optimum morphology of hybrid materials are of great interest in many applications. Morphology control has been extensively used as a direct tool in the evaluation of interactions and assemblies of components in thin films. It is believed that preparation method and composition are powerful tools to direct the morphology, particularly in self-assembled systems such as fullerene-based hybrid materials. The present report outlines a synergistic self-assembly of fullerenes (C(60)) and functionalized poly (p-phenylene) (PPP) to develop nanofibers with high aspect ratios. Nanostructured PPP-C(60) hybrids were prepared by direct casting of the dilute solution on solid substrates and on water under ambient conditions. The formation of whiskers with high aspect ratio and investigation of interesting photophysical properties are discussed. An amphiphilic PPP was used as a template for preparing nanohybrids of C(60) at ambient temperature and conditions.

  7. Binding of calixarene-based Langmuir monolayers to mercury chloride is dependent on the amphiphile structure

    Energy Technology Data Exchange (ETDEWEB)

    Tulli, Ludovico G.; Wang, Wenjie; Rullaud, Vanessa; Lindemann, William R.; Kuzmenko, Ivan; Vaknin, David; Shahgaldian, Patrick

    2016-01-01

    Two amphiphilic calix[4]arenes bearing four dodecyl chains at the lower rim and two amino functions (vicinal and distal) at the para-phenolic positions have been synthesized. Surface-pressure versus molecular-area isotherms reveal that Langmuir monolayers of the two regioisomers show considerably distinct self-assembly behaviors at the air–water interface. Compression isotherms, Brewster angle microscopy and synchrotron-based X-ray near-total-reflection fluorescence, X-ray reflectivity and grazing incidence X-ray diffraction reveal that the monolayers of the two diamino calix[4]arene derivatives and those of their structural analogues bearing four amino moieties in para positions exhibit significant differences in their binding properties towards HgCl2 despite the structural and functional similarity among the macrocycles.

  8. Solution Behavior of Amphiphilic Glycodendrimers with a Rod-Like Core.

    Science.gov (United States)

    Ordanini, Stefania; Zanchetta, Giuliano; Porkolab, Vanessa; Ebel, Christine; Fieschi, Franck; Guzzetti, Ileana; Potenza, Donatella; Palmioli, Alessandro; Podlipnik, Črtomir; Meroni, Daniela; Bernardi, Anna

    2016-06-01

    Glycodendrimers based on aromatic cores have an amphiphilic character and have been reported to generate supramolecuar assemblies in water. A new group of glycodendrimers with an aromatic rod-like core were recently described as potent antagonists of DC-SIGN-mediated viral infections. A full characterization of the aggregation properties of these materials is presented here. The results show that these compounds exist mostly as monomers in water solution, in dynamic equilibrium with small aggregates (dimers or trimers). Larger aggregates observed by dynamic light scattering and transmission Electron Microscopy for some of the dendrimers are found to be portions of materials not fully solubilized and can be removed either by optimizing the dissolution protocol or by centrifugation of the samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Porphyrin-based cationic amphiphilic photosensitisers as potential anticancer, antimicrobial and immunosuppressive agents.

    Science.gov (United States)

    Malatesti, Nela; Munitic, Ivana; Jurak, Igor

    2017-04-01

    Photodynamic therapy (PDT) combines a photosensitiser, light and molecular oxygen to induce oxidative stress that can be used to kill pathogens, cancer cells and other highly proliferative cells. There is a growing number of clinically approved photosensitisers and applications of PDT, whose main advantages include the possibility of selective targeting, localised action and stimulation of the immune responses. Further improvements and broader use of PDT could be accomplished by designing new photosensitisers with increased selectivity and bioavailability. Porphyrin-based photosensitisers with amphiphilic properties, bearing one or more positive charges, are an effective tool in PDT against cancers, microbial infections and, most recently, autoimmune skin disorders. The aim of the review is to present some of the recent examples of the applications and research that employ this specific group of photosensitisers. Furthermore, we will highlight the link between their structural characteristics and PDT efficiency, which will be helpful as guidelines for rational design and evaluation of new PSs.

  10. Fusion-fission transport of probes and quenchers in microdomains of an amphiphilic ionene polyelectrolyte.

    Science.gov (United States)

    Tcacenco, Celize M; Quina, Frank H

    2007-01-01

    In aqueous solution, amphiphilic ionenes such as the [3,22]-ionene spontaneously adopt globular conformations and form microdomains that are highly micelle-like, i.e. are capable of solubilizing organic molecules, binding and exchanging counterions and accelerating or inhibiting the rates of bimolecular reactions. Time-resolved fluorescence decay of pyrene and pyrene derivatives solubilized in these microdomains at concentrations where excimer formation occurs show that even water-insoluble probes can migrate between the hydrophobic microdomains formed in aqueous solution by a [3,22]-ionene chloride (with the N-terminal groups quaternized with benzyl chloride). Time-resolved studies of the quenching of pyrene fluorescence by alkylpyridine derivatives revealed similar behavior. The observed quenching behavior requires that the migration be between microdomains on the same ionene chain or same group of associated ionene chains and is consistent with migration dominated by fusion/fission transport of the probe and quencher.

  11. Structure-property relationship in cytotoxicity and cell uptake of poly(2-oxazoline) amphiphiles

    KAUST Repository

    Luxenhofer, Robert

    2011-07-01

    The family of poly(2-oxazoline)s (POx) is being increasingly investigated in the context of biomedical applications. We tested the relative cytotoxicity of POx and were able to confirm that these polymers are typically not cytotoxic even at high concentrations. Furthermore, we report structure-uptake relationships of a series of amphiphilic POx block copolymers that have different architectures, molar mass and chain termini. The rate of endocytosis can be fine-tuned over a broad range by changing the polymer structure. The cellular uptake increases with the hydrophobic character of the polymers and is observed even at nanomolar concentrations. Considering the structural versatility of this class of polymers, the relative ease of preparation and their stability underlines the potential of POx as a promising platform candidate for the preparation of next-generation polymer therapeutics.

  12. Application of amphiphilic catalysts, ultrasonication, and nanoemulsions for biodiesel production process

    Energy Technology Data Exchange (ETDEWEB)

    Ye, X.; Singh, A. [Department of Agricultural and Biological Engineering, Mississippi State University (United States); Wilson, W. [Department of Chemistry, Mississippi State University (United States); Fernando, S.

    2007-11-15

    This paper studies tuning heterogeneous transesterification catalysis and process for easy catalyst separation and enhanced reaction rate. Multibond metal alkoxides and ultrasonic pretreatment are employed to produce nanoemulsions with large interfacial area, which have the potential to be easily separated. With aluminum isopropoxide or titanium isopropoxide as the catalyst and surfactant, transparent alcohol/oil emulsions can be formed in less than four minutes and can significantly enhance the transesterification reaction rate. The micelle size was observed to be as low as 5.1 nm. Partially polymerized titanium isopropoxide also showed good catalytic activity and considerable amphiphilic properties in forming nanoemulsions. Viscosity and apparent vapor pressure reduction were also observed. The alcohol/soybean oil molar ratio was a main factor for apparent vapor pressure reduction. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  13. pH-Sensitive Amphiphilic Block-Copolymers for Transport and Controlled Release of Oxygen

    KAUST Repository

    Patil, Yogesh Raghunath

    2017-05-31

    Saturated fluorocarbons, their derivatives and emulsions are capable of dissolving anomalously high amounts of oxygen and other gases. The mechanistic aspects of this remarkable effect remain to be explored experimentally. Here, the synthesis of a library of amphiphilic fluorous block-copolymers incorporating different fluorinated monomers is described, and the capacity of these copolymers for oxygen transport in water is systematically investigated. The structure of the fluorous monomer employed was found to have a profound effect on both the oxygen-carrying capacity and the gas release kinetics of the polymer emulsions. Furthermore, the release of O2 from the polymer dispersions could be triggered by changing the pH of the solution. This is the first example of a polymer-based system for controlled release of a non-polar, non-covalently entrapped respiratory gas.

  14. Amphiphilic block copolymer-based photonic platform towards efficient protein detection

    Science.gov (United States)

    Petropoulou, Afroditi; Gibson, Thomas J.; Themistou, Efrosyni; Pispas, Stergios; Riziotis, Christos

    2016-11-01

    The development of a low complexity fiber optic based protein sensor by functionalizing the surface of silica optical fibers using block copolymers having both hydrophobic poly(methyl methacrylate) (PMMA) and hydrophilic poly[2- (dimethylamino)ethyl methacrylate] (PDMAEMA) blocks is presented here. The amphiphilic thiol-functionalized PMMA117-b-P(DMAEMA17-st-TEMA2) and vinyl-sulfone PMMA117-b-P(DMAEMA17-st-VSTEMA2) block copolymers designed and synthesized in this work contain a cationic hydrophilic PDMAEMA block that can electrostatically bind selected oppositely charged proteins and also appropriate functional groups for reversible or non-reversible protein binding, respectively, leading to a refractive index change of the overlayer and hence, enabling the sensing. The developed PMMA117-b-PDMAEMA16-based platform has been evaluated for bovine serum albumin (BSA) sensing, exhibiting linear response to detected BSA concentrations.

  15. Synthesis and characterization of some binary and ternary zirconium iodides

    Energy Technology Data Exchange (ETDEWEB)

    Guthrie, D.H.

    1981-10-01

    Studies of binary ZrI/sub 4/-Zr and ternary CsI-Zr-ZrI/sub 4/ systems have produced several new compounds. The new binary compounds include two polymorphs of ZrI/sub 2/ (..cap alpha.. and ..beta..) as well as a phase described earlier as ZrI/sub 1/ /sub 8/. ..cap alpha..-ZrI/sub 2/ forms as black lath-like crystals by vapor phase transport reactions between Zr and ZrI/sub 4/ from 700 to 825/sup 0/C. Its structure is monoclinic space group P2/sub 1//m with a = 6.821(2), b = 3.741(1), c = 14.937(3) A and ..beta.. = 95.66(3)/sup 0/, Z = 4 (R = 0.064). ..beta..-ZrI/sub 2/ is formed as black gem-like crystals between 800 to 975/sup 0/C, crystallizing in the trigonal space group R anti 3 with hexagonal axes a = 14.502(2) and c = 9.996(2) A, Z = 18 (R = 0.109). This phase contains a Zr/sub 6/I/sub 12/ cluster. Guinier x-ray powder diffraction data previously reported for ZrI/sub 1/ /sub 8/ has now been found to arise from ..cap alpha..-ZrI/sub 2/ intergrown with an orthorhombic ZrI/sub 2/ phase (perhaps isostructural with WTe/sub 2/ plus an unknown phase. The ternary compounds include Cs/sub 2/ZrI/sub 6/, Cs/sub 3/Zr/sub 2/T/sub 9/ and CsZr/sub 6/I/sub 14/. The first is isostructural with K/sub 2/PtCl/sub 6/. Cs/sub 3/Zr/sub 2/I/sub 9/ is formed from the reaction of CsI, ZrI/sub 4/ and Zr between 700 to 900/sup 0/C as black gem-like crystals which crystallize in the space group P6/sub 3//mmc with a = 8.269(1) and c = 19.908(3) A, z = 2. This phase was found to have a Cs/sub 3/Cr/sub 2/Cl/sub 9/-type structure, d/sub Zr-Zr/ = 3.134(4) A (R = 0.087). CsZr/sub 6/I/sub 14/ forms both rod and gem crystals by the same reaction with more metal between 900 to 950/sup 0/C. It crystallizes in the orthorhombic space group Ccmb with a = 14.275(4), b = 15.880(4) and c = 12.953 (4) A (R = 0.062). This phase also contains a Zr/sub 6/I/sub 12/ cluster.

  16. Investigation of itraconazole ternary amorphous solid dispersions based on povidone and Carbopol.

    Science.gov (United States)

    Meng, Fan; Meckel, Jordan; Zhang, Feng

    2017-08-30

    We investigate a ternary system that consists of itraconazole (ITZ) and two polymers: povidone K12 and Carbopol 907. The interactions between these two polymers and their effects on the properties of ternary ITZ amorphous solid dispersions (ASDs) are studied. These two polymers can form a water-insoluble complex in acidic aqueous media. The critical pH is determined to be 4.17. The weight percentage of Carbopol 907 in the interpolymer complex range from 59 to 70%, depending on the initial ratios between these two polymers in the starting solutions. This complexation is driven by a negative enthalpy change from the H-bonding between the two polymers and a positive entropy change from the freed water molecules. Due to the slow precipitation of the interpolymer complex in aqueous media, the attempt to prepare ternary ASD using solvent-controlled coprecipitation is not successful. Melt extrusion is identified to be the only viable method to prepare this ternary ASD. We find that interpolymer complex-based ASDs are physically less stable and demonstrate the poorest drug-release properties when compared to individual polymer-based binary ASDs. This study illustrates that the too strong interaction between polymers in ternary ASDs is detrimental to their performance. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Heteronanostructured Co@carbon nanotubes-graphene ternary hybrids: synthesis, electromagnetic and excellent microwave absorption properties

    Science.gov (United States)

    Qi, Xiaosi; Hu, Qi; Cai, Hongbo; Xie, Ren; Bai, Zhongchen; Jiang, Yang; Qin, Shuijie; Zhong, Wei; Du, Youwei

    2016-11-01

    In order to explore high efficiency microwave absorption materials, heteronanostructured Co@carbon nanotubes-graphene (Co@CNTs-G) ternary hybrids were designed and produced through catalytic decomposition of acetylene at the designed temperature (400, 450, 500 and 550 °C) over Co3O4/reduced graphene oxide (Co3O4/RGO). By regulating the reaction temperatures, different CNT contents of Co@CNTs-G ternary hybrids could be synthesized. The investigations indicated that the as-prepared heteronanostructured Co@CNTs-G ternary hybrids exhibited excellent microwave absorption properties, and their electromagnetic and microwave absorption properties could be tuned by the CNT content. The minimum reflection loss (RL) value reached approximately -65.6, -58.1, -41.1 and -47.5 dB for the ternary hybrids synthesized at 400, 450, 500 and 550 °C, respectively. And RL values below -20 dB (99% of electromagnetic wave attenuation) could be obtained over the as-prepared Co@CNTs-G ternary hybrids in the large frequency range. Moreover, based on the obtained results, the possible enhanced microwave absorption mechanisms were discussed in details. Therefore, a simple approach was proposed to explore the high performance microwave absorbing materials as well as to expand the application field of graphene-based materials.

  18. Theoretical investigation on electronic and mechanical properties of ternary actinide (U, Np, Pu) nitrides

    Science.gov (United States)

    Zhang, Yu-Juan; Zhou, Zhang-Jian; Lan, Jian-Hui; Bo, Tao; Ge, Chang-Chun; Chai, Zhi-Fang; Shi, Wei-Qun

    2017-09-01

    Actinide mononitrides as a promising advanced nuclear fuel have recently earned much attention. We herein studied the electronic and mechanical properties of the ternary actinide mixed mononitrides A0.5B0.5 N (A, B = U, Np, and Pu) using the density functional theory +U method. It is found that in the studied ternary mixed mononitrides, the 5f electronic states of all actinide atoms maintain the local electronic character and do not overlap with each other. Compared with their corresponding binary mononitrides, the U-N bond becomes more ionic, where the Np-N and Pu-N bonds become more covalent in ternary actinide mixed mononitrides. The mechanical properties (such as bulk and shear moduli, Young's modulus, and Poisson's ratio) of three ternary actinide (U-Pu) mononitrides are found to be similar to that of their corresponding binary actinide mononitrides and thus are expected not to misbehave with actinide mononitrides in respect of mechanics. In addition, all the three ternary actinide mononitrides have no imaginary frequencies in their vibration curves and correspondingly satisfy the stability criteria for elastic constants of tetragonal structures.

  19. Dynamic solidification mechanism of ternary Ag-Cu-Ge eutectic alloy under ultrasonic condition

    Science.gov (United States)

    Zhai, Wei; Hong, ZhenYu; Mei, CeXiang; Wang, WeiLi; Wei, BingBo

    2013-02-01

    The dynamic solidification of ternary Ag38.5Cu33.4Ge28.1 eutectic alloy within a 35 kHz ultrasonic field is investigated and compared with both its equilibrium solidification by DSC method and its rapid solidification in drop tube. The volume fractions of the primary (Ge) phase and pseudobinary (Ag+ ɛ 2) eutectic solidified within ultrasonic field are larger than those formed under equilibrium state, whereas that of ternary (Ag+ ɛ 2+Ge) eutectic exhibits the reverse trend. During rapid solidification, the liquid alloy droplet directly solidifies into ternary (Ag+ ɛ 2+Ge) eutectic if its diameter is smaller than 350 μm. The ultrasound stimulates the nucleation of alloy melt and prevents the bulk undercooling. With the increase of sound intensity, the primary (Ge) phase transfers from faceted dendrites to nonfaceted blocks with blunt edges, and its grain size is remarkably reduced. Both pseudobinary (Ag+ ɛ 2) and ternary (Ag+ ɛ 2+Ge) eutectics experience a morphological transition from regular to anomalous structures. This indicates that their cooperative growth mode is replaced by independent growth of eutectic phases under the combined effects of cavitation and acoustic streaming. The ultrasound also shows a prominent coarsening effect to the pseudobinary (Ag+ ɛ 2) and ternary (Ag+ ɛ 2 +Ge) eutectics.

  20. Experimental and predicted refractive index properties in ternary mixtures of associated liquids

    Energy Technology Data Exchange (ETDEWEB)

    Sechenyh, Vitaliy V.; Legros, Jean-Claude [MRC - Microgravity Research Centre, Universite Libre de Bruxelles (ULB), CP165/62, Avenue F.D. Roosevelt 50, B-1050 Brussels (Belgium); Shevtsova, Valentina, E-mail: vshev@ulb.ac.be [MRC - Microgravity Research Centre, Universite Libre de Bruxelles (ULB), CP165/62, Avenue F.D. Roosevelt 50, B-1050 Brussels (Belgium)

    2011-11-15

    Highlights: > Measurements of refractive indices of 200 different aqueous ternary mixtures have been performed for two wave lengths. > Refractive indices of the associated ternary mixtures can be modeled with a relative error of about 0.9. > Difference between experimental and calculated derivatives of refractive index with concentration is unsatisfactory large. - Abstract: Refractive indices of ternary mixtures formed by (water + ethanol + k-ethylene glycol) (when k is mono, di or tri) and (water + t-butanol + dimethyl sulfoxide) are presented over a wide range of mixture compositions. All measurements have been conducted at 298.15 K and atmospheric pressure using two light sources: one in the visible ({lambda} = 670 nm) and the other in the infrared ({lambda} = 925 nm) spectrum. The performance of several mixing rules that are commonly used in modeling optical constants are examined. We demonstrate that the refractive indices of the associated ternary mixtures can be modeled with a relative error of about 0.9% by using the thermodynamical properties of the pure components. The concentration derivatives of the refractive index are an important parameter, as they are required for different experimental techniques. These derivatives have been determined from the experimental data on refractive indices. However, applying mixing rules for calculation of the derivatives of the refractive indices with respect to concentrations does not provide satisfactory results in the case of ternary mixtures of associated liquids.

  1. Crystallization, data collection and processing of the chymotrypsin–BTCI–trypsin ternary complex

    Energy Technology Data Exchange (ETDEWEB)

    Esteves, Gisele Ferreira; Teles, Rozeni Chagas Lima; Cavalcante, Nayara Silva; Neves, David; Ventura, Manuel Mateus [Laboratório de Biofísica, Instituto de Ciências Biológicas, Universidade de Brasília, 70910-900 Brasília-DF (Brazil); Barbosa, João Alexandre Ribeiro Gonçalves, E-mail: joao@lnls.br [Center for Structural Molecular Biology (CeBiME), Brazilian Synchrotron Light Laboratory (LNLS), CP 6192, 13083-970 Campinas-SP (Brazil); Freitas, Sonia Maria de, E-mail: joao@lnls.br [Laboratório de Biofísica, Instituto de Ciências Biológicas, Universidade de Brasília, 70910-900 Brasília-DF (Brazil)

    2007-12-01

    A ternary complex of the proteinase inhibitor (BTCI) with trypsin and chymotrypsin was crystallized and its crystal structure was solved by molecular replacement. A ternary complex of the black-eyed pea trypsin and chymotrypsin inhibitor (BTCI) with trypsin and chymotrypsin was crystallized by the sitting-drop vapour-diffusion method with 0.1 M HEPES pH 7.5, 10%(w/v) polyethylene glycol 6000 and 5%(v/v) 2-methyl-2,4-pentanediol as precipitant. BTCI is a small protein with 83 amino-acid residues isolated from Vigna unguiculata seeds and is able to inhibit trypsin and chymotrypsin simultaneously by forming a stable ternary complex. X-ray data were collected from a single crystal of the trypsin–BTCI–chymotrypsin ternary complex to 2.7 Å resolution under cryogenic conditions. The structure of the ternary complex was solved by molecular replacement using the crystal structures of the BTCI–trypsin binary complex (PDB code) and chymotrypsin (PDB code) as search models.

  2. Gene expression of ternary complexes through the compaction of nanofiber-polyplexes by mixing with lipofectamine.

    Science.gov (United States)

    Aono, Ryuta; Nomura, Kenta; Yuba, Eiji; Harada, Atsushi; Kono, Kenji

    2015-05-01

    For the development of an effective nonviral gene vector, ternary complexes were prepared through the compaction of nanofiber-polyplexes. These were formed using pDNA and a head-tail type polycation bearing a multi-arm poly(ethylene glycol) head and a poly(l-lysine) tail, and this strategy was based on the crowding effect of poly(ethylene glycol) in the polyplex. Mixing was carried out using a cationic lipid (lipofectamine), which is a commercially available transfection reagent. Through ternary complex formation, the elongated morphology of nanofiber-polyplexes was found to compact into a spherical shape with an average diameter of ca. 100 nm. Accompanying ternary complex formation, the compaction of the nanofiber-polyplexes can improve cellular uptake and helps the ternary complex to retain its smooth transcription/translation process, which is characteristic of nanofiber-polyplexes. As a result, ternary complexes prepared at an optimal mixing ratio exhibit a high transfection efficiency compared with lipofectamine lipoplexes.

  3. Positively charged amphiphilic chitosan derivative for the transscleral delivery of rapamycin.

    Science.gov (United States)

    Elsaid, Naba; Jackson, Timothy L; Gunic, Mirza; Somavarapu, Satyanarayana

    2012-12-13

    We explored the potential of an amphiphilic chitosan derivative to facilitate the transscleral delivery of rapamycin, a potential multitherapeutic agent with poor water solubility. The amphiphilic chitosan derivative, O-octanoyl-chitosan-polyethylene glycol (OChiPEG) graft copolymer, was analyzed using Fourier-transform infrared spectroscopy (FT-IR). OChiPEG micelles were prepared via the thin film method and characterized for their size using dynamic light scattering (DLS), zeta potential using laser Doppler velocimetry (LDV), morphology using transmission electron microscopy (TEM), drug entrapment efficiency (EE), and drug loading (DL) efficiency using reversed-phase high performance liquid chromatography (RP-HPLC), critical micelle concentration (CMC) using spectrofluorometry, and thermal properties using differential scanning calorimetry (DSC) and x-ray powder diffraction (XRPD). Scleral permeation and retention of rapamycin from the drug-loaded micelles were determined in porcine sclera clamped in Ussing chambers, using RP-HPLC. Conjugation of hydrophilic and hydrophobic groups to chitosan was confirmed using FT-IR. Rapamycin-loaded micelles of particle size 40.6 nm and zeta potential + 6.84 mV were prepared successfully. These carriers exhibited a high EE and DL of 85.6 and 16.3%, respectively, and a CMC of 16.6 μM. OChiPEG micelles showed a high rapamycin scleral retention (14.8 ± 0.81 μg/g) with successful transscleral permeation (5.57 ± 1.04 × 10(-8) cm(2) · s(-1)). Positively charged OChiPEG micelles loaded with rapamycin were prepared successfully. These showed a high scleral retention and successful permeation of rapamycin, and therefore may be useful for the topical delivery of other hydrophobic agents.

  4. Self assembly of amphiphilic C60 fullerene derivatives into nanoscale supramolecular structures

    Science.gov (United States)

    Partha, Ranga; Lackey, Melinda; Hirsch, Andreas; Casscells, S Ward; Conyers, Jodie L

    2007-01-01

    Background The amphiphilic fullerene monomer (AF-1) consists of a "buckyball" cage to which a Newkome-like dendrimer unit and five lipophilic C12 chains positioned octahedrally to the dendrimer unit are attached. In this study, we report a novel fullerene-based liposome termed 'buckysome' that is water soluble and forms stable spherical nanometer sized vesicles. Cryogenic electron microscopy (Cryo-EM), transmission electron microscopy (TEM), and dynamic light scattering (DLS) studies were used to characterize the different supra-molecular structures readily formed from the fullerene monomers under varying pH, aqueous solvents, and preparative conditions. Results Electron microscopy results indicate the formation of bilayer membranes with a width of ~6.5 nm, consistent with previously reported molecular dynamics simulations. Cryo-EM indicates the formation of large (400 nm diameter) multilamellar, liposome-like vesicles and unilamellar vesicles in the size range of 50–150 nm diameter. In addition, complex networks of cylindrical, tube-like aggregates with varying lengths and packing densities were observed. Under controlled experimental conditions, high concentrations of spherical vesicles could be formed. In vitro results suggest that these supra-molecular structures impose little to no toxicity. Cytotoxicity of 10–200 μM buckysomes were assessed in various cell lines. Ongoing studies are aimed at understanding cellular internalization of these nanoparticle aggregates. Conclusion In this current study, we have designed a core platform based on a novel amphiphilic fullerene nanostructure, which readily assembles into supra-molecular structures. This delivery vector might provide promising features such as ease of preparation, long-term stability and controlled release. PMID:17683530

  5. Amphiphilic polymeric micelle as pseudostationary phase in electrokinetic chromatography for analysis of eight corticosteroids in cosmetics.

    Science.gov (United States)

    Xu, Xiaojin; Ni, Xinjiong; Cao, Yuhua; Zhuo, Xiaolu; Yang, Xiaoxiao; Cao, Guangqun

    2014-03-01

    Amphiphilic polymeric micelle, as a novel pseudostationary phase in EKC was used to determine eight kinds of corticosteroids namely hydrocortisone, prednisolone, hydrocortisone acetate, prednisone, cortisone acetate, prednisolone acetate, dexamethasone, and triamcinolone acetonide in cosmetics. Amphiphilic random copolymer poly(methyl methacrylate-co-methacrylic acid) (P(MMA-co-MAA)) was micellizated via neutralization in alkaline aqueous solution. The influences of the molar ratio of monomer MMA to MAA, the concentration of polymer and pH on the polymeric micelle microstructure and EKC performances were investigated. As molar ratio of MMA to MAA in P(MMA-co-MAA) increased, both CMC and environmental polarity of the inner core in polymeric micelle decreased dramatically. With increasing monomer ratio, the size of polymeric micelles increased firstly, and then decreased, finally increased again. ζ potential of the micelle had a slight decline trend. As increment of polymer concentration, the size of the polymeric micelle increased steadily. By optimizing the monomer ratio, the polymer concentration, and pH of the running buffer, as well as operation conditions such as separation voltage and temperature, the eight analytes could be separated within 16.5 min using 7.5 mg/mL polymer with the monomer ratio of 7:3 dissolved in pH 9.2 borax buffer as the running buffer. The method has been used for analysis of corticosteroids in cosmetic samples with simple extraction; the recoveries for eight analytes were between 85.9 and 106%. This method was of accuracy, repeatability, pretreatment simplicity, and could be applied to the quality control of cosmetics. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Self assembly of amphiphilic C60 fullerene derivatives into nanoscale supramolecular structures

    Directory of Open Access Journals (Sweden)

    Casscells S Ward

    2007-08-01

    Full Text Available Abstract Background The amphiphilic fullerene monomer (AF-1 consists of a "buckyball" cage to which a Newkome-like dendrimer unit and five lipophilic C12 chains positioned octahedrally to the dendrimer unit are attached. In this study, we report a novel fullerene-based liposome termed 'buckysome' that is water soluble and forms stable spherical nanometer sized vesicles. Cryogenic electron microscopy (Cryo-EM, transmission electron microscopy (TEM, and dynamic light scattering (DLS studies were used to characterize the different supra-molecular structures readily formed from the fullerene monomers under varying pH, aqueous solvents, and preparative conditions. Results Electron microscopy results indicate the formation of bilayer membranes with a width of ~6.5 nm, consistent with previously reported molecular dynamics simulations. Cryo-EM indicates the formation of large (400 nm diameter multilamellar, liposome-like vesicles and unilamellar vesicles in the size range of 50–150 nm diameter. In addition, complex networks of cylindrical, tube-like aggregates with varying lengths and packing densities were observed. Under controlled experimental conditions, high concentrations of spherical vesicles could be formed. In vitro results suggest that these supra-molecular structures impose little to no toxicity. Cytotoxicity of 10–200 μM buckysomes were assessed in various cell lines. Ongoing studies are aimed at understanding cellular internalization of these nanoparticle aggregates. Conclusion In this current study, we have designed a core platform based on a novel amphiphilic fullerene nanostructure, which readily assembles into supra-molecular structures. This delivery vector might provide promising features such as ease of preparation, long-term stability and controlled release.

  7. Screening Nylon-3 Polymers, a New Class of Cationic Amphiphiles, for siRNA Delivery

    Science.gov (United States)

    2015-01-01

    Amphiphilic nucleic acid carriers have attracted strong interest. Three groups of nylon-3 copolymers (poly-β-peptides) possessing different cationic/hydrophobic content were evaluated as siRNA delivery agents in this study. Their ability to condense siRNA was determined in SYBR Gold assays. Their cytotoxicity was tested by MTT assays, their efficiency of delivering Alexa Fluor-488-labeled siRNA intracellularly in the presence and absence of uptake inhibitors was assessed by flow cytometry, and their transfection efficacies were studied by luciferase knockdown in a cell line stably expressing luciferase (H1299/Luc). Endosomal release was determined by confocal laser scanning microscopy and colocalization with lysotracker. All polymers efficiently condensed siRNA at nitrogen-to-phosphate (N/P) ratios of 5 or lower, as reflected in hydrodynamic diameters smaller than that at N/P 1. Although several formulations had negative zeta potentials at N/P 1, G2C and G2D polyplexes yielded >80% uptake in H1299/Luc cells, as determined by flow cytometry. Luciferase knockdown (20–65%) was observed after transfection with polyplexes made of the high molecular weight polymers that were the most hydrophobic. The ability of nylon-3 polymers to deliver siRNA intracellularly even at negative zeta potential implies that they mediate transport across cell membranes based on their amphiphilicity. The cellular uptake route was determined to strongly depend on the presence of cholesterol in the cell membrane. These polymers are, therefore, very promising for siRNA delivery at reduced surface charge and toxicity. Our study identified nylon-3 formulations at low N/P ratios for effective gene knockdown, indicating that nylon-3 polymers are a new, promising type of gene delivery agent. PMID:25437915

  8. Microspheres made of poly(epsilon-caprolactone)-based amphiphilic copolymers: potential in sustained delivery of proteins.

    Science.gov (United States)

    Quaglia, Fabiana; Ostacolo, Luisanna; Nese, Giuseppe; De Rosa, Giuseppe; La Rotonda, Maria Immacolata; Palumbo, Rosario; Maglio, Giovanni

    2005-10-20

    Microspheres of amphiphilic multi-block poly(ester-ether)s (PEE)s and poly(ester-ether-amide)s (PEEA)s based on poly(epsilon-caprolactone) (PCL) were investigated as delivery systems for proteins. The interest was mainly focused on the effect of their molecular structure and composition on the overall properties of the microspheres, encapsulating bovine serum albumin (BSA) as a model protein. PEEs and PEEAs were prepared using a alpha,omega-dihydroxy-terminated PCL macromer (Mn= 2.0 kDa) as a hydrophobic component. Hydrophilic oxyethylene sequences were generated using poly(ethylene oxide)s (PEO)s of different molecular mass (Mn= 300-600 Da) in the case of PEEs, or 4,7,10-trioxa-1,13-tridecanediamine (Trioxy) and PEO150 (Mn= 150 Da) in the case of PEEAs. The copolymers showed a decrease of Tm and crystallinity values as compared with PCL. Within each class of copolymers, the bulk hydrophilicity increased with increasing the number of oxyethylene groups in the chain repeat unit. PEEAs were more hydrophilic than PEEs with a similar number of oxyethylene groups. Discrete spherical particles were prepared by both PEEs and PEEAs and their BSA encapsulation efficiency related to copolymer properties. Interestingly, the insertion of short hydrophilic segments is enough to significantly affect protein distribution inside microspheres and its release profiles, as compared to PCL microspheres. Different degradation rates and mechanisms were observed for copolymer microspheres, mainly depending on the distribution of oxyethylene units along the chain. The results highlight that a fine control over the structural parameters of amphiphilic PCL-based multi-block copolymers is a key factor for their application in the field of protein delivery.

  9. An effective dispersant for oil spills based on food-grade amphiphiles.

    Science.gov (United States)

    Athas, Jasmin C; Jun, Kelly; McCafferty, Caitlyn; Owoseni, Olasehinde; John, Vijay T; Raghavan, Srinivasa R

    2014-08-12

    Synthetic dispersants such as Corexit 9500A were used in large quantities (∼2 million gallons) to disperse the oil spilled in the ocean during the recent Deepwater Horizon event. These dispersant formulations contain a blend of surfactants in a base of organic solvent. Some concerns have been raised regarding the aquatic toxicity and environmental impact of these formulations. In an effort to create a safer dispersant, we have examined the ability of food-grade amphiphiles to disperse (emulsify) crude oil in seawater. Our studies show that an effective emulsifier is obtained by combining two such amphiphiles: lecithin (L), a phospholipid extracted from soybeans, and Tween 80 (T), a surfactant used in many food products including ice cream. Interestingly, we find that L/T blends show a synergistic effect, i.e., their combination is an effective emulsifier, but neither L or T is effective on its own. This synergy is maximized at a 60/40 weight ratio of L/T and is attributed to the following reasons: (i) L and T pack closely at the oil-water interface; (ii) L has a low tendency to desorb, which fortifies the interfacial film; and (iii) the large headgroup of T provides steric repulsions between the oil droplets and prevents their coalescence. A comparison of L/T with Corexit 9500A shows that the former leads to smaller oil droplets that remain stable to coalescence for a much longer time. The smaller size and stability of crude oil droplets are believed to be important to their dispersion and eventual microbial degradation in the ocean. Our findings suggest that L/T blends could potentially be a viable alternative for the dispersion of oil spills.

  10. Screening nylon-3 polymers, a new class of cationic amphiphiles, for siRNA delivery.

    Science.gov (United States)

    Nadithe, Venkatareddy; Liu, Runhui; Killinger, Bryan A; Movassaghian, Sara; Kim, Na Hyung; Moszczynska, Anna B; Masters, Kristyn S; Gellman, Samuel H; Merkel, Olivia M

    2015-02-02

    Amphiphilic nucleic acid carriers have attracted strong interest. Three groups of nylon-3 copolymers (poly-β-peptides) possessing different cationic/hydrophobic content were evaluated as siRNA delivery agents in this study. Their ability to condense siRNA was determined in SYBR Gold assays. Their cytotoxicity was tested by MTT assays, their efficiency of delivering Alexa Fluor-488-labeled siRNA intracellularly in the presence and absence of uptake inhibitors was assessed by flow cytometry, and their transfection efficacies were studied by luciferase knockdown in a cell line stably expressing luciferase (H1299/Luc). Endosomal release was determined by confocal laser scanning microscopy and colocalization with lysotracker. All polymers efficiently condensed siRNA at nitrogen-to-phosphate (N/P) ratios of 5 or lower, as reflected in hydrodynamic diameters smaller than that at N/P 1. Although several formulations had negative zeta potentials at N/P 1, G2C and G2D polyplexes yielded >80% uptake in H1299/Luc cells, as determined by flow cytometry. Luciferase knockdown (20-65%) was observed after transfection with polyplexes made of the high molecular weight polymers that were the most hydrophobic. The ability of nylon-3 polymers to deliver siRNA intracellularly even at negative zeta potential implies that they mediate transport across cell membranes based on their amphiphilicity. The cellular uptake route was determined to strongly depend on the presence of cholesterol in the cell membrane. These polymers are, therefore, very promising for siRNA delivery at reduced surface charge and toxicity. Our study identified nylon-3 formulations at low N/P ratios for effective gene knockdown, indicating that nylon-3 polymers are a new, promising type of gene delivery agent.

  11. Totally Organic Redox-Active pH-Sensitive Nanoparticles Stabilized by Amphiphilic Aromatic Polyketones.

    Science.gov (United States)

    Araya-Hermosilla, Esteban; Catalán-Toledo, José; Muñoz-Suescun, Fabián; Oyarzun-Ampuero, Felipe; Raffa, Patrizio; Polgar, Lorenzo Massimo; Picchioni, Francesco; Moreno-Villoslada, Ignacio

    2018-02-08

    Amphiphilic aromatic polymers have been synthesized by grafting aliphatic polyketones with 4-(aminomethyl)benzoic acid at different molar ratios via the Paal-Knorr reaction. The resulting polymers, showing diketone conversion degree of 16%, 37%, 53%, and 69%, have been complexed with the redox-active 2,3,5-triphenyl-2H-tetrazolium chloride, a precursor molecule with which aromatic-aromatic interactions are held. Upon addition of ascorbic acid to the complexes, in situ reduction of the tetrazolium salt produced 1,3,5-triphenylformazan nanoparticles stabilized by the amphiphilic polymers. The stabilized nanoparticles display highly negative zeta potential [-(35-70) mV] and hydrodynamic diameters in the submicron range (100-400 nm). Nonaromatic polyelectrolytes or hydrophilic aromatic copolymers showing low linear aromatic density and high linear charge density such as acrylate/maleate and sulfonate/maleate-containing polymers were unable to stabilize formazan nanoparticles synthesized by the same method. The copolymers studied here bear uncharged nonaromatic comonomers (unreacted diketone units) as well as charged aromatic comonomers, which furnish amphiphilia. Thus, the linear aromatic density and the maximum linear charge density have the same value for each copolymer, and the hydrophilic/hydrophobic balance varies with the diketone conversion degree. The amphiphilia of the copolymers allows the stabilization of the nanoparticles, even with the copolymers showing a low linear aromatic density. The method of nanoparticle synthesis constitutes a simple, cheap, and green method for the production of switchable totally organic, redox-active, pH-sensitive nanoparticles that can be reversibly turned into macroprecipitates upon pH changing.

  12. Physico-chemical characterization of an amphiphilic cyclodextrin/genistein complex.

    Science.gov (United States)

    Cannavà, C; Crupi, V; Ficarra, P; Guardo, M; Majolino, D; Mazzaglia, A; Stancanelli, R; Venuti, V

    2010-04-06

    Specific recognition of cell-targeting systems as host-carriers modified with receptor targeting groups, is a major ambition in the application of supramolecular science to medicine and life science. Genistein (Gen), an isoflavone belonging to the class of phytoestrogens, is of great interest because it has been considered as potential remedy for many kinds of disease. In this work, genistein in aqueous medium and in the presence of an host nanocarrier as amphiphilic cyclodextrin (CyD) modified in the upper rim with oligoethylene hydroxyl groups [(2-oligo(ethyleneoxide)-6-hexylthio)-beta-CyD, SC6OH] at 1:1 molar ratio, has been firstly investigated by UV-vis measurements coupled with circular dichroism data, in order to characterize the drug/macrocycle binding affinity through the formation of the complex. Furthermore, FTIR-ATR technique has been used to detect the complex formation in solid phase and to characterize the functional groups responsible of the solid Gen/SC6OH complex stability. The infrared absorbance spectra of the complex, collected in a wide range of wavenumber and around the physiological temperature, have been analysed and compared with the spectra of the pure compounds and their physical mixture. By monitoring the most significant changes in the shape and position of the absorbance bands of the Gen functional groups, we showed that the formation and/or modification of polar bonds play the main role in the interaction of the drug with the amphiphilic CyD. From the results, Gen is shown to be entangled in SC6OH nanoaggregates, establishing hydrogen bonding with the hydrophilic PEG chains. Copyright 2009 Elsevier B.V. All rights reserved.

  13. Electrochemical combustion of indigo at ternary oxide coated titanium anodes

    Directory of Open Access Journals (Sweden)

    María I. León

    2014-12-01

    Full Text Available The film of iridium and tin dioxides doped with antimony (IrO2-SnO2–Sb2O5 deposited on a Ti substrate (mesh obtained by Pechini method was used for the formation of ·OH radicals by water discharge. Detection of ·OH radicals was followed by the use of the N,N-dimethyl-p-nitrosoaniline (RNO as a spin trap. The electrode surface morphology and composition was characterized by SEM-EDS. The ternary oxide coating was used for the electrochemical combustion of indigo textile dye as a model organic compound in chloride medium. Bulk electrolyses were then carried out at different volumetric flow rates under galvanostatic conditions using a filter-press flow cell. The galvanostatic tests using RNO confirmed that Ti/IrO2-SnO2-Sb2O5 favor the hydroxyl radical formation at current densities between 5 and 7 mA cm-2, while at current density of 10 mA cm-2 the oxygen evolution reaction occurs. The indigo was totally decolorized and mineralized via reactive oxygen species, such as (·OH, H2O2, O3 and active chlorine formed in-situ at the Ti/IrO2-SnO2-Sb2O5 surface at volumetric flow rates between 0.1-0.4 L min-1 and at fixed current density of 7 mA cm-2. The mineralization of indigo carried out at 0.2 L min-1 achieved values of 100 %, with current efficiencies of 80 % and energy consumption of 1.78 KWh m-3.

  14. Mathematical representation of electrophoretic mobility in ternary solvent electrolyte systems

    Directory of Open Access Journals (Sweden)

    "Jouyban A

    2002-09-01

    Full Text Available Electrophoretic mobilities of salmeterol and phenylpropanolamine in capillary zone electrophoresis were determined using acetate buffer in mixed solvents containing different concentrations of water, methanol and acetonitrile. Maximum electrophoretic mobilities for salmeterol and phenylpropanolamine were observed with water-methanol-acetonitrile ratios of 5:50:45 v/v and 3:60:37 v/v, respectively, and minimum mobilities of both compounds occurred in methanol-acetonitrile ratio of 30:70 v/v. The generated experimental data have been used to evaluate a mathematical model to compute the electrophoretic mobility of the analytes in a ternary solvent electrolyte system. The proposed model is: ln μm =ƒ1 ln μ1+ƒ2 ln μ2+k ƒ3+M1ƒ1 ƒ2+M2 ƒ1ƒ3+M3 ƒ2ƒ3+M4 ƒ1ƒ²1+M5 ƒ²2ƒ3+M6ƒ²2ƒ3+M7ƒ1ƒ2ƒ3. Where μ is the electrophoretic mobility, subscripts m,1, 2 and 3 refer to mixed solvent and solvents 1-3, respectively, f is the volume fraction of the solvent in the mixed solvent system and M1-M7 and K are the model constants calculated by a least squares analysis. The generated experimental data fitted to the model and the back-calculated mobilities were employed to compute the average percentage deviation (APD as an accuracy criterion. The obtained APD for salmeterol and phenylpropanolamine are 3.10 and 2.21%, respectively and the low APD values indicate that the model is able to calculate the mobilities within an acceptable error range.

  15. Luminescent properties of ytterbium-doped ternary lanthanum chloride

    Energy Technology Data Exchange (ETDEWEB)

    Kaminska, A., E-mail: kaminska@ifpan.edu.pl [Institute of Physics, Polish Academy of Sciences, 02-668 Warsaw (Poland); Cybinska, J. [Faculty of Chemistry, University of Wroclaw, Joliot-Curie 14, 50-383 Wroclaw (Poland); Zhydachevskii, Ya. [Institute of Physics, Polish Academy of Sciences, 02-668 Warsaw (Poland); Lviv Polytechnic National University, 12 Bandera, Lviv 79646 (Ukraine); Sybilski, P. [Institute of Physics, Polish Academy of Sciences, 02-668 Warsaw (Poland); Meyer, G. [Department of Chemistry, University of Cologne, Greinstrasse 6, D-50939 Koeln (Germany); Suchocki, A. [Institute of Physics, Polish Academy of Sciences, 02-668 Warsaw (Poland); Institute of Physics, University of Bydgoszcz, Weyssenhoffa 11, 85-072, Bydgoszcz (Poland)

    2011-07-28

    Highlights: > Ytterbium-doped ternary lanthanum chloride as a promising light-emitting material. > The luminescence properties of K{sub 2}LaCl{sub 5}:Yb{sup 3+} powders with different Yb concentration. > Very good temperature stability of the powders for higher Yb concentration. - Abstract: Studies of the absorption and temperature dependence of photoluminescence spectra and luminescence decay times of the intra-shell f-f transitions ({sup 2}F{sub 5/2} {r_reversible} {sup 2}F{sub 7/2}) of Yb{sup 3+} ions in K{sub 2}LaCl{sub 5}:Yb{sup 3+} powders with 5, 10, 15 and 25% of ytterbium are presented. The spectroscopic properties of the powders with different ytterbium content are compared. Experiments were performed at the temperatures from 25 to 300 K. The strong emission around 982 nm has been observed under direct excitation of the luminescence center with 960 nm line of continuous wave Ti:sapphire laser pumped by Ar-ion laser. The temperature quenching effect of the luminescence was rather week, especially in the samples with higher concentration of ytterbium (15 and 25%). Additionally the probability of the f-f radiative transitions of the Yb{sup 3+} ions in these powders was almost temperature independent for more heavily doped samples (with 15 and 25% of Yb) and only weakly temperature dependent for less doped samples (with 5 and 10% of Yb). These results reveal high thermal stability of the optical properties of the examined powders.

  16. Review of Reactivity Experiments for Lithium Ternary Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Jolodosky, A. [Univ. of California, Berkeley, CA (United States); Bolind, A. [Univ. of California, Berkeley, CA (United States); Fratoni, M. [Univ. of California, Berkeley, CA (United States)

    2015-09-28

    Lithium is often the preferred choice as breeder and coolant in fusion blankets as it offers high tritium breeding, excellent heat transfer and corrosion properties, and most importantly, it has very high tritium solubility and results in very low levels of tritium permeation throughout the facility infrastructure. However, lithium metal vigorously reacts with air and water and exacerbates plant safety concerns. Consequently, Lawrence Livermore National Laboratory (LLNL) is attempting to develop a lithium-based alloy—most likely a ternary alloy—which maintains the beneficial properties of lithium (e.g. high tritium breeding and solubility) while reducing overall flammability concerns for use in the blanket of an inertial fusion energy (IFE) power plant. The LLNL concept employs inertial confinement fusion (ICF) through the use of lasers aimed at an indirect-driven target composed of deuterium-tritium fuel. The fusion driver/target design implements the same physics currently experimented at the National Ignition Facility (NIF). The plant uses lithium in both the primary coolant and blanket; therefore, lithium related hazards are of primary concern. Reducing chemical reactivity is the primary motivation for the development of new lithium alloys, and it is therefore important to come up with proper ways to conduct experiments that can physically study this phenomenon. This paper will start to explore this area by outlining relevant past experiments conducted with lithium/air reactions and lithium/water reactions. Looking at what was done in the past will then give us a general idea of how we can setup our own experiments to test a variety of lithium alloys.

  17. Ternary eutectic dendrites: Pattern formation and scaling properties

    Science.gov (United States)

    Rátkai, László; Szállás, Attila; Pusztai, Tamás; Mohri, Tetsuo; Gránásy, László

    2015-04-01

    Extending previous work [Pusztai et al., Phys. Rev. E 87, 032401 (2013)], we have studied the formation of eutectic dendrites in a model ternary system within the framework of the phase-field theory. We have mapped out the domain in which two-phase dendritic structures grow. With increasing pulling velocity, the following sequence of growth morphologies is observed: flat front lamellae → eutectic colonies → eutectic dendrites → dendrites with target pattern → partitionless dendrites → partitionless flat front. We confirm that the two-phase and one-phase dendrites have similar forms and display a similar scaling of the dendrite tip radius with the interface free energy. It is also found that the possible eutectic patterns include the target pattern, and single- and multiarm spirals, of which the thermal fluctuations choose. The most probable number of spiral arms increases with increasing tip radius and with decreasing kinetic anisotropy. Our numerical simulations confirm that in agreement with the assumptions of a recent analysis of two-phase dendrites [Akamatsu et al., Phys. Rev. Lett. 112, 105502 (2014)], the Jackson-Hunt scaling of the eutectic wavelength with pulling velocity is obeyed in the parameter domain explored, and that the natural eutectic wavelength is proportional to the tip radius of the two-phase dendrites. Finally, we find that it is very difficult/virtually impossible to form spiraling two-phase dendrites without anisotropy, an observation that seems to contradict the expectations of Akamatsu et al. Yet, it cannot be excluded that in isotropic systems, two-phase dendrites are rare events difficult to observe in simulations.

  18. High-throughput development of amphiphile self-assembly materials: fast-tracking synthesis, characterization, formulation, application, and understanding.

    Science.gov (United States)

    Mulet, Xavier; Conn, Charlotte E; Fong, Celesta; Kennedy, Danielle F; Moghaddam, Minoo J; Drummond, Calum J

    2013-07-16

    Amphiphile self-assembly materials, which contain both a hydrophilic and a hydrophobic domain, have great potential in high-throughput and combinatorial approaches to discovery and development. However, the materials chemistry community has not embraced these ideas to anywhere near the extent that the medicinal chemistry community has. While this situation is beginning to change, extracting the full potential of high-throughput approaches in the development of self-assembling materials will require further development in the synthesis, characterization, formulation, and application domains. One of the key factors that make small molecule amphiphiles prospective building blocks for next generation multifunctional materials is their ability to self-assemble into complex nanostructures through low-energy transformations. Scientists can potentially tune, control, and functionalize these structures, but only after establishing their inherent properties. Because both robotic materials handling and customized rapid characterization equipment are increasingly available, high-throughput solutions are now attainable. These address traditional development bottlenecks associated with self-assembling amphiphile materials, such as their structural characterization and the assessment of end-use functional performance. A high-throughput methodology can help streamline materials development workflows, in accord with existing high-throughput discovery pipelines such as those used by the pharmaceutical industry in drug discovery. Chemists have identified several areas that are amenable to a high-throughput approach for amphiphile self-assembly materials development. These allow an exploration of not only a large potential chemical, compositional, and structural space, but also material properties, formulation, and application variables. These areas of development include materials synthesis and preparation, formulation, characterization, and screening performance for the desired end

  19. Synthesis and evaluation of amphiphilic peptides as nanostructures and drug delivery tools

    Science.gov (United States)

    Sayeh, Naser Ali

    conjugates although one limitation lies in the effort of controlling the rate of drug release. The encapsulated or complexed drugs tend to be released rapidly (before reaching the target site) and in the dendrimer--drug conjugates, it is the chemical linkage that controls the drug release. Thus, future studies in this field are urgently required to create more efficient and stable biomaterials. Peptides are considered as efficient vectors for achieving optimal cellular uptake. The potential use of peptides as drug delivery vectors received much attention by the discovery of several cell-penetrating peptides (CPPs). The first CPPs discovered in 1988, that were sequences from HIV-1 encoded TAT protein, TAT (48--60), and penetrated very efficiently through cell membranes of cultured mammalian cells. CPPs are a class of diverse peptides, typically with 8--25 amino acids, and unlike most peptides, they can cross the cellular membrane with more efficiency. CPPs have also shown to undergo self-assembly and generate nanostructures. The generation of self-assembled peptides and nanostructures occur through various types of interactions between functional groups of amino acid residues, such as electrostatic, hydrophobic, and hydrogen bonding. Appropriate design and functionalization of peptides are critical for generating nanostructures. Chemically CPPs are classified into two major groups: linear and cyclic peptides. It has been previously reported that linear peptides containing hydrophilic and hydrophobic amino acids could act as membrane protein stabilizers. These compounds are short hydrophilic or amphiphilic peptides that have positively charged amino acids, such as arginine, lysine or histidine, which can interact with the negative charge phospholipids layer on the cell membrane and translocate the cargo into the cells. Conjugation to cationic linear CPPs, such as TAT, penetratin, or oligoarginine efficiently improves the cellular uptake of large hydrophilic molecules, but the

  20. A microstructure-composition map of a ternary liquid/liquid/particle system with partially-wetting particles.

    Science.gov (United States)

    Yang, Junyi; Roell, David; Echavarria, Martin; Velankar, Sachin S

    2017-11-22

    We examine the effect of composition on the morphology of a ternary mixture comprising two molten polymeric liquid phases (polyisobutylene and polyethylene oxide) and micron-scale spherical silica particles. The silica particles were treated with silanes to make them partially wetted by both polymers. Particle loadings up to 30 vol% are examined while varying the fluid phase ratios across a wide range. Numerous effects of particle addition are catalogued, stabilization of Pickering emulsions and of interfacially-jammed co-continuous microstructures, meniscus-bridging of particles, particle-induced coalescence of the dispersed phase, and significant shifts in the phase inversion composition. Many of the effects are asymmetric, for example particle-induced coalescence is more severe and drop sizes are larger when polyisobutylene is the continuous phase, and particles promote phase continuity of the polyethylene oxide. These asymmetries are likely attributable to a slight preferential wettability of the particles towards the polyethylene oxide. A state map is constructed which classifies the various microstructures within a triangular composition diagram. Comparisons are made between this diagram vs. a previous one constructed for the case when particles are fully-wetted by polyethylene oxide.

  1. Viscosities of the ternary solution dimethyl sulfoxide/water/sodium chloride at subzero temperatures and their application in cryopreservation.

    Science.gov (United States)

    Zhang, Shaozhi; Yu, Xiaoyi; Chen, Zhaojie; Chen, Guangming

    2013-04-01

    Vitrification is considered as the most promising method for long-term storage of tissues and organs. An effective way to reduce the accompanied cryoprotectant (CPA) toxicity, during CPA addition/removal, is to operate at low temperatures. The permeation process of CPA into/out of biomaterials is affected by the viscosity of CPA solution, especially at low temperatures. The objective of the present study is to measure the viscosity of the ternary solution, dimethyl sulfoxide (Me2SO)/water/sodium chloride (NaCl), at low temperatures and in a wide range of concentrations. A rotary viscometer coupled with a low temperature thermostat bath was used. The measurement was carried out at temperatures from -10 to -50°C. The highest mass fraction of Me2SO was 75% (w/w) and the lowest mass fraction of Me2SO was the value that kept the solution unfrozen at the measurement temperature. The concentration of NaCl was kept as a constant [0.85% (w/w), the normal salt content of extracellular fluids]. The Williams-Landel-Ferry (WLF) model was employed to fit the obtained viscosity data. As an example, the effect of solution viscosity on modeling the permeation of Me2SO into articular cartilage was qualitatively analyzed. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Ternary ceramic thermal spraying powder and method of manufacturing thermal sprayed coating using said powder

    Energy Technology Data Exchange (ETDEWEB)

    Vogli, Evelina; Sherman, Andrew J.; Glasgow, Curtis P.

    2018-02-06

    The invention describes a method for producing ternary and binary ceramic powders and their thermal spraying capable of manufacturing thermal sprayed coatings with superior properties. Powder contain at least 30% by weight ternary ceramic, at least 20% by weight binary molybdenum borides, at least one of the binary borides of Cr, Fe, Ni, W and Co and a maximum of 10% by weight of nano and submicro-sized boron nitride. The primary crystal phase of the manufactured thermal sprayed coatings from these powders is a ternary ceramic, while the secondary phases are binary ceramics. The coatings have extremely high resistance against corrosion of molten metal, extremely thermal shock resistance and superior tribological properties at low and at high temperatures.

  3. Efficient Implementation of Ternary SDM Filters using State-of-the-Art FPGA

    Directory of Open Access Journals (Sweden)

    Tayabuddin Memon

    2011-04-01

    Full Text Available We present the analysis of a ternary FIR filter at varying OSR (Over Sampling Ratios. The sigma delta modulated ternary filter impulse responses obtained using Matlab at varying OSRs show that each doubling of OSR results in an increase of 10dB in the stopband attenuation. BT-FIR (Balanced Ternary FIR Filters at varying OSRs have been implemented in VHDL using an efficient adder tree organization to gather the partial products. Filters in both pipelined and non-pipelined modes were synthesized on a small number of representative commercial FPGA (Field Programmable Gate Arrays devices. Both the filter taps and binary inputs use 2\\'s complement format. The synthesis results show the tradeoffs between hardware area and performance at varying OSRs. In pipelined mode, a 6MHz video stream can easily be handled at an OSR of 64, while occupying less than 8% of a Stratix-III device.

  4. H2SO4-HNO3-H2O ternary system in the stratosphere

    Science.gov (United States)

    Kiang, C. S.; Hamill, P.

    1974-01-01

    Estimation of the equilibrium vapor pressure over the ternary system H2SO4-HNO3-H2O to study the possibility of stratospheric aerosol formation involving HNO3. It is shown that the vapor pressures for the ternary system H2SO4-HNO3-H2O with weight composition around 70-80% H2SO4, 10-20% HNO3, 10-20% H2O at -50 C are below the order of 10 to the minus 8th mm Hg. It is concluded that there exists more than sufficient nitric acid and water vapor in the stratosphere to participate in ternary system aerosol formation at -50 C. Therefore, HNO3 should be present in stratospheric aerosols, provided that H2SO4 is also present.

  5. Thermodynamic description of the Al-Cu-Yb ternary system supported by first-principles calculations

    Directory of Open Access Journals (Sweden)

    Huang G.

    2016-01-01

    Full Text Available Phase relationships of the ternary Al-Cu-Yb system have been assessed using a combination of CALPHAD method and first principles calculations. A self-consistent thermodynamic parameter was established based on the experimental and theoretical information. Most of the binary intermetallic phases, except Al3Yb, Al2Yb, Cu2Yb and Cu5Yb, were assumed to be zero solubility in the ternary system. Based on the experimental data, eight ternary intermetallic compounds were taken into consideration in this system. Among them, three were treated as line compounds with large homogeneity ranges for Al and Cu. The others were treated as stoichiometric compounds. The calculated phase diagrams were in agreement with available experimental and theoretical data.

  6. A Novel Method for Detecting and Computing Univolatility Curves in Ternary Mixtures

    DEFF Research Database (Denmark)

    Shcherbakov, Nataliya; Rodriguez-Donis, Ivonne; Abildskov, Jens

    2017-01-01

    of the generalized univolatility and unidistribution curves in the three dimensional composition – temperature state space lead to a simple and efficient algorithm of computation of the univolatility curves. Two peculiar ternary systems, namely diethylamine – chloroform – methanol and hexane – benzene......Residue curve maps (RCMs) and univolatility curves are crucial tools for analysis and design of distillation processes. Even in the case of ternary mixtures, the topology of these maps is highly non-trivial. We propose a novel method allowing detection and computation of univolatility curves...... in homogeneous ternary mixtures independently of the presence of azeotropes, which is particularly important in the case of zeotropic mixtures. The method is based on the analysis of the geometry of the boiling temperature surface constrained by the univolatility condition. The introduced concepts...

  7. Experimental investigation of phase equilibria in the Ni-Nb-V ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xingjun; Yang, Shuiyuan; Wang, Cuiping [Xiamen Univ. (China). Dept. of Materials Science and Engineering; Xiamen Univ. (China). Fujian Provincial Key Lab. of Materials Genome; Zhang, Xianjie; Jiang, Hengxing; Shi, Zhan [Xiamen Univ. (China). Dept. of Materials Science and Engineering

    2017-09-15

    The phase equilibria of the Ni-Nb-V ternary system at 1000 C and 1200 C were established using electron probe microanalysis, X-ray diffraction and differential scanning calorimetry. The results of the investigation revealed that: (1) The Nb solubility in (Ni) and σ{sup '} phases was less than 10 at.%; (2) A ternary compound τ (NiNbV) was confirmed, in which V had a large solubility; (3) A new liquid region was evident at 1200 C, but was absent at 1000 C; (4) The lattice constants of Ni{sub 3}Nb and Ni{sub 6}Nb{sub 7} phase decreased with increase in V content in the Ni{sub 3}Nb and Ni{sub 6}Nb{sub 7}. The phase equilibria of the Ni-Nb-V ternary system will contribute to its thermodynamic assessment.

  8. Binary and ternary cocrystals of sulfa drug acetazolamide with pyridine carboxamides and cyclic amides

    Directory of Open Access Journals (Sweden)

    Geetha Bolla

    2016-03-01

    Full Text Available A novel design strategy for cocrystals of a sulfonamide drug with pyridine carboxamides and cyclic amides is developed based on synthon identification as well as size and shape match of coformers. Binary adducts of acetazolamide (ACZ with lactams (valerolactam and caprolactam, VLM, CPR, cyclic amides (2-pyridone, labeled as 2HP and its derivatives MeHP, OMeHP and pyridine amides (nicotinamide and picolinamide, NAM, PAM were obtained by manual grinding, and their single crystals by solution crystallization. The heterosynthons in the binary cocrystals of ACZ with these coformers suggested a ternary combination for ACZ with pyridone and nicotinamide. Novel supramolecular synthons of ACZ with lactams and pyridine carboxamides are reported together with binary and ternary cocrystals for a sulfonamide drug. This crystal engineering study resulted in the first ternary cocrystal of acetazolamide with amide coformers, ACZ–NAM–2HP (1:1:1.

  9. Ternary mixture of fatty acids as phase change materials for thermal energy storage applications

    Directory of Open Access Journals (Sweden)

    Karunesh Kant

    2016-11-01

    Full Text Available The present study deals with the development of ternary mixtures of fatty acids for low temperature thermal energy storage applications. The commercial grade fatty acids such as Capric Acid (CA, Lauric Acid (LA, Palmitic Acid (PA and Stearic Acid (SA, have been used to prepare stable, solid–liquid phase change material (PCM for the same. In this regard, a series of ternary mixture i.e. CA–LA–SA (CLS and CA–PA–SA (CPS have been developed with different weight percentages. Thermal characteristics of these developed ternary mixture i.e. melting temperature and latent heat of fusion have been measured by using Differential Scanning Calorimeter (DSC technique. The synthesized materials are found to have melting temperature in the range of 14–21 °C (along with adequate amount of latent heat of fusion, which may be quite useful for several low temperature thermal energy storage applications.

  10. Ternary critical point determination of experimental demixion curve: calculation method, relevance and limits

    Directory of Open Access Journals (Sweden)

    Goutaudier C.

    2013-07-01

    Full Text Available In many cases of miscibility gap in ternary systems, one critical point at least, stable or metastable, can be observed under isobaric and isothermal conditions. The experimental determination of this invariant point is difficult but its knowledge is essential. The authors propose a method for calculating the composition of the invariant solution starting from the composition of the liquid phases in equilibrium. The computing method is based on the barycentric properties of the conjugate solutions (binodal points and an extension of the straight diameter method. A systematic study was carried out on a large number of ternary systems involving diverse constituents (230 sets ternary systems at various temperatures. Thus the results are presented and analyzed by means of consistency tests.

  11. [Synthesis and luminescence properties of ternary complexes of europium with aromatic carboxylic acid and acrylonitrile].

    Science.gov (United States)

    Guo, Dong-cai; Yi, Li-ming; Shu, Wan-gen; Zhang, Zhen-zhen; Zeng, Zhao-rong; Zhang, Xi-qian

    2006-11-01

    Five ternary complexes were synthesized from europium with aromatic carboxylic acid (p-methylbenzoic acid, methoxybenzoic acid, m-chlorobenzoic acid and benzoic acid, p-hydroxylbenzoic acid) and acrylonitrile, and characterized by means of elemental analysis, thermal analysis, FTIR spectra and UV spectra. The fluorescence spectra show that five ternary complexes have good luminescence properties, and the sequence of the ability of the aromatic carboxylic acids to transfer light energy to europium ion is as follows: p-methylbenzoic acid>benzoic acid>m-chlorobenzoic acid>p-hydroxylbenzoic acid>methoxybenzoic acid. Meanwhile, the ternary europium complexes containing a reactive ligand acrylonitrile will possibly have a potential application to the fabrication of bonding-type europium polymer luminescent materials.

  12. Colloidal and antibacterial properties of novel triple-headed, double-tailed amphiphiles: exploring structure-activity relationships and synergistic mixtures.

    Science.gov (United States)

    Marafino, John N; Gallagher, Tara M; Barragan, Jhosdyn; Volkers, Brandi L; LaDow, Jade E; Bonifer, Kyle; Fitzgerald, Gabriel; Floyd, Jason L; McKenna, Kristin; Minahan, Nicholas T; Walsh, Brenna; Seifert, Kyle; Caran, Kevin L

    2015-07-01

    Two novel series of tris-cationic, tripled-headed, double-tailed amphiphiles were synthesized and the effects of tail length and head group composition on the critical aggregation concentration (CAC), thermodynamic parameters, and minimum inhibitory concentration (MIC) against six bacterial strains were investigated. Synergistic antibacterial combinations of these amphiphiles were also identified. Amphiphiles in this study are composed of a benzene core with three benzylic ammonium bromide groups, two of which have alkyl chains, each 8-16 carbons in length. The third head group is a trimethylammonium or pyridinium. Log of critical aggregation concentration (log[CAC]) and heat of aggregation (ΔHagg) were both inversely proportional to the length of the linear hydrocarbon chains. Antibacterial activity increases with tail length until an optimal tail length of 12 carbons per chain, above which, activity decreased. The derivatives with two 12 carbon chains had the best antibacterial activity, killing all tested strains at concentrations of 1-2μM for Gram-positive and 4-16μM for Gram-negative bacteria. The identity of the third head group (trimethylammonium or pyridinium) had minimal effect on colloidal and antibacterial activity. The antibacterial activity of several binary combinations of amphiphiles from this study was higher than activity of individual amphiphiles, indicating that these combinations are synergistic. These amphiphiles show promise as novel antibacterial agents that could be used in a variety of applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Phase Relations in Ternary Systems in the Subsolidus Region: Methods to Formulate Solid Solution Equations and to Find Particular Compositions

    Science.gov (United States)

    Alvarez-Montan~o, Victor E.; Farías, Mario H.; Brown, Francisco; Mun~oz-Palma, Iliana C.; Cubillas, Fernando; Castillon-Barraza, Felipe F.

    2017-01-01

    A good understanding of ternary phase diagrams is required to advance and/or to reproduce experimental research in solid-state and materials chemistry. The aim of this paper is to describe the solutions to problems that appear when studying or determining ternary phase diagrams. A brief description of the principal features shown in phase diagrams…

  14. A ternary memory module using low-voltage control over optical properties of metal-polypyridyl monolayers.

    Science.gov (United States)

    Kumar, Anup; Chhatwal, Megha; Mondal, Prakash Chandra; Singh, Vikram; Singh, Alok Kumar; Cristaldi, Domenico A; Gupta, Rinkoo D; Gulino, Antonino

    2014-04-14

    A ternary memory module has been designed as a function of precise voltage command. The monolayer based module displays perpetual stability and non-hysteretic reversibility for multiple scans (10(2)). Ternary-state readout provides a vision to integrate the next generation of "smart electro-optical devices" viable for multi-state memory.

  15. Fluid mechanics in fluids at rest.

    Science.gov (United States)

    Brenner, Howard

    2012-07-01

    Using readily available experimental thermophoretic particle-velocity data it is shown, contrary to current teachings, that for the case of compressible flows independent dye- and particle-tracer velocity measurements of the local fluid velocity at a point in a flowing fluid do not generally result in the same fluid velocity measure. Rather, tracer-velocity equality holds only for incompressible flows. For compressible fluids, each type of tracer is shown to monitor a fundamentally different fluid velocity, with (i) a dye (or any other such molecular-tagging scheme) measuring the fluid's mass velocity v appearing in the continuity equation and (ii) a small, physicochemically and thermally inert, macroscopic (i.e., non-Brownian), solid particle measuring the fluid's volume velocity v(v). The term "compressibility" as used here includes not only pressure effects on density, but also temperature effects thereon. (For example, owing to a liquid's generally nonzero isobaric coefficient of thermal expansion, nonisothermal liquid flows are to be regarded as compressible despite the general perception of liquids as being incompressible.) Recognition of the fact that two independent fluid velocities, mass- and volume-based, are formally required to model continuum fluid behavior impacts on the foundations of contemporary (monovelocity) fluid mechanics. Included therein are the Navier-Stokes-Fourier equations, which are now seen to apply only to incompressible fluids (a fact well-known, empirically, to experimental gas kineticists). The findings of a difference in tracer velocities heralds the introduction into fluid mechanics of a general bipartite theory of fluid mechanics, bivelocity hydrodynamics [Brenner, Int. J. Eng. Sci. 54, 67 (2012)], differing from conventional hydrodynamics in situations entailing compressible flows and reducing to conventional hydrodynamics when the flow is incompressible, while being applicable to both liquids and gases.

  16. Data and analyses of phase relations in the Ce-Fe-Sb ternary system.

    Science.gov (United States)

    Zhu, Daiman; Xu, Chengliang; Li, Changrong; Guo, Cuiping; Zheng, Raowen; Du, Zhenmin; Li, Junqin

    2018-02-01

    These data and analyses support the research article "Experimental study on phase relations in the Ce-Fe-Sb ternary system" Zhu et al. (2017) [1]. The data and analyses presented here include the experimental results of XRD, SEM and EPMA for the determination of the whole liquidus projection and the isothermal section at 823 K in the Ce-Fe-Sb system. All the results enable the understanding of the constituent phases and the solidification processes of the as-cast alloys as well as the phase relations and the equilibrium regions at 823 K in the Ce-Fe-Sb ternary system over the entire composition.

  17. All ternary permutation constraint satisfaction problems parameterized above average have kernels with quadratic numbers of variables

    DEFF Research Database (Denmark)

    Gutin, Gregory; Van Iersel, Leo; Mnich, Matthias

    2010-01-01

    A ternary Permutation-CSP is specified by a subset Π of the symmetric group S3. An instance of such a problem consists of a set of variables V and a multiset of constraints, which are ordered triples of distinct variables of V. The objective is to find a linear ordering α of V that maximizes...... the number of triples whose rearrangement (under α) follows a permutation in Π. We prove that all ternary Permutation-CSPs parameterized above average have kernels with quadratic numbers of variables....

  18. OBJECT TRACKING WITH ROTATION-INVARIANT LARGEST DIFFERENCE INDEXED LOCAL TERNARY PATTERN

    Directory of Open Access Journals (Sweden)

    J Shajeena

    2017-02-01

    Full Text Available This paper presents an ideal method for object tracking directly in the compressed domain in video sequences. An enhanced rotation-invariant image operator called Largest Difference Indexed Local Ternary Pattern (LDILTP has been proposed. The Local Ternary Pattern which worked very well in texture classification and face recognition is now extended for rotation invariant object tracking. Histogramming the LTP code makes the descriptor resistant to translation. The histogram intersection is used to find the similarity measure. This method is robust to noise and retain contrast details. The proposed scheme has been verified on various datasets and shows a commendable performance.

  19. Ternary chalcogenide micro-pseudocapacitors for on-chip energy storage

    KAUST Repository

    Kurra, Narendra

    2015-05-11

    We report the successful fabrication of a micro-pseudocapacitor based on ternary nickel cobalt sulfide for the first time, with performance substantially exceeding that of previously reported micro-pseudocapacitors based on binary sulfides. CoNi2S4 micro-pseudocapacitor exhibits a maximum energy density of 18.7 mWh/cm3 at a power density of 1163 mW/cm3, opens up an avenue for exploring new family of ternary oxides/sulfides based micro-pseudocapacitors.

  20. Glass transition behavior of ternary disaccharide-ethylene glycol-water solutions

    Science.gov (United States)

    Yu, Tongxu; Zhao, Lishan; Wang, Qiang; Cao, Zexian

    2017-06-01

    Glass transition behavior of ternary disaccharide-ethylene glycol-water solutions, in reference to that of the binary combinations, has been investigated towards a better understanding of their cryoprotective ability. In water-deficient solutions, the disaccharides, including trehalose, sucrose and maltose, can associate with more than 100 ethylene glycol molecules to form amorphous complex, one order of magnitude larger than the corresponding hydration numbers. In water-rich solutions, a second glass transition emerges with increasing molar fraction of ethylene glycol, indicating the possible synergy of disaccharides and ethylene glycol in vitrification of the ternary aqueous solution.