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  • 1401. Zhang, H
    et al.
    Smith, P
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Adler-Nissen, J
    Effects of degree of enzymatic interesterification on the physical properties of margarine fats – Solid fat content, crystallization behavior, crystal morphology and crystal network2004In: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, E-ISSN 1520-5118, Vol. 52, p. 4423-4431Article in journal (Refereed)
    Abstract [en]

    In this study enzymatic-interesterified margarine fats with different conversion degrees were produced in a packed bed reactor. The effects of conversion degree on the formation of free fatty acids and diglycerides, solid fat content, crystallization behavior, microstructure, and crystal network were investigated and the enzymatically interesterified products were compared with a chemically esterified product. Formation of free fatty acids, and diacyglycerols increased slightly with increasing conversion degree. The solid fat content was higher at 10 and 20∞C and lower at 30, 35, and 40∞C with the increasing conversion degree. Addition of 50% of rapeseed oil into the blend and products caused the content of b to decreas from 100 to 33, and 30% and eventually to pure b’ crystal. However, double chain packing was observed both for the blend and products. Isothermal crystallization kinetics was characterized by the Fisher-Turnbull model. Highest free energy was observed for the blend. Small deformation with oscillation tests shows significant difference between the blend and interesterified products. The differences of microstructure between the blend, different conversion degree and chemical randomized product were observed. Lipozyme TL IM, interesterification, packed-bed reactor, crystallization, nuclear magnetic resonance (NMR), DSC, X-ray, and light microscopy.

  • 1402.
    Zhmud, B
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Interaction between charge-regulated surfaces in the presence of polyelectrolytes2006In: Russian Journal of Physical Chemistry, ISSN 0036-0244, E-ISSN 1531-863X, Vol. 80, no 1 S.1, p. S177-S184Article in journal (Refereed)
    Abstract [en]

    This work gives a brief overview of the backgrounds of the self-consistent mean-field theory as applied to the problem of interaction betweencharge-regulated surfaces in the presence of polyelectrolytes. A general algorithm of obtaining a self-consistent solution is described, and the asymptotic properties of the solution at close separations are analysed. Known limitations of the self-consistent field approximation are discussed highlighting the role of local effects and system equilibration.

  • 1403.
    Zhmud, B
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Tiberg, F
    Interfacial dynamics and structure of surfactant layers2005In: Advances in Colloid and Interface Science, ISSN 0001-8686, E-ISSN 1873-3727, Vol. 113, p. 21-42Article in journal (Refereed)
    Abstract [en]

    The present article covers both the theoretical aspects of surfactant adsorption and the modern experimental methods for studying the properties of adsorbed surfactant layers. The principles of ellipsometry, photon correlation spectroscopy, small angle neutron scattering, and neutron reflectivity are explained in detail. A special attention is paid to the surface tension relaxation in micellar solutions, the properties of mixed surfactants, the wetting enhancement, and the damping effect of surfactant films on capillary waves

  • 1404.
    Zhmud, Boris V
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Tiberg, Fredrik
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Surfactants in ink-jet inks2003In: Surfactants in Polymers, Coatings, Inks and Adhesives / [ed] David R. Karsa, Blackwell Publishing, 2003, p. 211-244Chapter in book (Refereed)
  • 1405. Zhmud, B.V.
    et al.
    Bergström, L
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Charge regulation at the surface of a porous solid1999In: Surfaces of Nanoparticles and Porous Materials / [ed] Schwarz, J.A. & Contescu, C., Marcel Dekker, 1999, p. 567-592Chapter in book (Refereed)
  • 1406.
    Zhmud, BV
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Bergström, L
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Dissolution kinetics of silicon nitride in aqueous suspension1999In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 218, p. 582-584Article in journal (Refereed)
    Abstract [en]

    A general system of equations describing the dissolution of polydisperse solids having a porous particulate structure is set up and applied to study the hydrolysis and subsequent dissolution of silicon nitride powder in aqueous suspensions. The latter process has been found to follow a simple kinetic equation, c(t) = cs[1-exp(-kt)], with the dissolution rate constant k = 2.3E-06 1/s and the saturation concentration, cs = 3.2 mmol/l at room temperature and pH9. The role of diffusion is unimportant, so that the concentration of soluble species in pore water changes almost simultaneously with their concentration in the surrounding solution.

  • 1407.
    Zhmud, BV
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Golub, AA
    Pivovarenko, VG
    Synthesis and study of ion adsorption and fluorescent properties of silica-grafted bis(crownazo)methine12004In: Inorg Mater, ISSN  0020-1685, Vol. 40, p. 1006-1013Article in journal (Refereed)
    Abstract [en]

    A ketocyanine ligand containing two N-aza-15-crown-5 residues has been synthesized and covalently anchored to a silica substrate through an azomethine link. The ligand formation and molecular structure have been determined by combining spectral data and molecular simulations. Preferential adsorption of rare-earth metals from aqueous solutions to the modified surface has been noticed. In the case of lanthanum, the adsorption is accompanied by significant fluorescence enhancement, which allows this system to be used as a sensor for La3+ion.

  • 1408.
    Zhmud, BV
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Meurk, A
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Bergström, L
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Application of charge regulation model for evaluation of surface ionization parameters from atomic force microscopy (AFM) data2000In: Colloids and Surfaces A: Physicochemical and Engineering Aspects, ISSN 0927-7757, E-ISSN 1873-4359, Vol. 164, p. 3-7Article in journal (Refereed)
    Abstract [en]

    The present state of affairs with calculation of electrostatic interaction between two charge regulated surfaces is briefly reviewed, placing a special emphasis on assumptions and limitations of underlying physical models. An application of the charge regulation model for evaluation of surface ionization parameters from the interaction force profile measured with an atomic force microscope in a symmetric silica¯silica system is demonstrated. The site density and the dissociation equilibrium constant of surface silanols are determined. As can be judged from the results obtained, surface silanols are considerably more acidic than it was considered before.

  • 1409.
    Zhmud, BV
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Meurk, A
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Bergström, L
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Evaluation of surface ionization parameters from AFM data1998In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 207, p. 332-343Article in journal (Refereed)
    Abstract [en]

    A new application of atomic force microscopy (AFM) for evaluation of surface ionization parameters on the basis of a charge regulation model is demonstrated. Interactions between symmetrical silicon nitride and silica surfaces have been measured in aqueous electrolytic solutions at different pH and separations from a few Debye lengths down to zero. The obtained experimental data are reported and interpreted on a quantitative level in the framework of Derjaguin's approximation; the computational procedure used for this purpose is outlined. Surface charge density, surface potential, and species concentrations are calculated as functions of pH and separation, unveiling the limits of applicability of classical constant-charge and constant-potential approximations. The integrity of the results on the charge properties of interacting surfaces is discussed in reference to electrokinetic and titration data; potential problems caused by the existence of non-DLVO forces and surface irregularities being highlighted.

  • 1410.
    Zhmud, BV
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Poptoshev, E
    Pugh, RJ
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Role of hydration and conformational changes in adsorption dynamics of ethyl(hydroxyethyl)cellulose at the air/solution interface1998In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 14, p. 3620-3624Article in journal (Refereed)
    Abstract [en]

    Previous studies have discussed the kinetics of the reduction in surface tension of ethyl(hydroxyethyl)cellulose (EHEC) at the air/aqueous solution interface in terms of configuration changes involved in the transfer of individual polymer segments between soluted and adsorbed state. It was suggested that the process kinetics were governed by a substantially high activation barrier. In the present study, based on molecular mechanic simulations, it is shown that a nearly activation-free path between configurations exists for EHEC due to the extreme flexibility of the polymer chain. Hence, the relatively slow kinetics of the process should rather be attributed to the step-wise transformation between conformations which is expressed as a sequence of elementary processes involving a large number of intermediate steps. This occurs over an extended time period. Also, the configuration changes involved in the uncoiling of the polymer at the interface are related to the hydration effects.

  • 1411.
    Zhmud, BV
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Sonnefeld, J
    Bergström, L
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Influence of chemical pretreatment on the surface properties of silicon nitride powder1999In: Colloids and Surfaces A: Physicochemical and Engineering Aspects, ISSN 0927-7757, E-ISSN 1873-4359, Vol. 158, p. 327-341Article in journal (Refereed)
    Abstract [en]

    Adsorption energy distributions for nitrogen at the surface of silicon nitride samples with different pretreatment have been obtained and related to the heats of adsorption determined by BET analysis of adsorption isotherms. This has confirmed the conjecture that, in normal conditions, the surface of silicon nitride is covered by a layer of silica, as suggested by earlier studies. An attempt to correlate adsorption data with ab initio potentials of the adsorbate-adsorbent interaction has been made. The charge-regulated behaviour of the surface of silicon nitride in aqueous electrolytic solutions has been investigated in relation to charge titration and electrokinetic experiments. An important role of surface hydrolysis in the interpretation of experimental data has been pointed out. Based on the surface ionization parameters extracted from charge titration data, interparticle forces governing the stability of colloidal dispersions have been calculated in the framework of Derjaguin's approximation.

  • 1412.
    Zhmud, BV
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Tiberg, F
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Hallstensson, K
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Dynamics of capillary rise2000In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 228, p. 263-269Article in journal (Refereed)
    Abstract [en]

    An overview and detailed analysis of the classical theory of capillarity is presented. A number of known equations of capillary rise dynamics are shown to be different limiting cases of one rather general equation. Some internal inconsistencies of the classical equations are pointed out. The role of non-linear dissipation and flow pattern effects in the front zone of the liquid column and near the capillary entrance is discussed. Numerical simulations and experimental data demonstrating some characteristic types of dynamic behavior predicted by the theory are reported. A special attention is paid to the capillary rise of surfactant solutions. As applied to this special case, the existing theory is substantially elaborated by setting up a closed system of equations describing the surfactant transport and relaxation processes in the adsorption layer. A simplified relation for the capillary rise dynamics in the case of strong depletion of the interfacial region is obtained, which is in qualitative agreement with the experimental behavior.

  • 1413.
    Zhmud, BV
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Tiberg, F
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Kizling, J
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Dynamic surface tension in concentrated solutions of CnEm Surfactants: A comparison between the theory and experiment2000In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 16, p. 2557-2565Article in journal (Refereed)
    Abstract [en]

    Dynamic surface tension (DST) measurements have been carried out with a series of CnE6-type surfactants with varying alkyl chain length (n = 10 to 16). Major emphasis has been placed on the DST relaxation in complex solutions containing both the micellar and monomer forms of surfactant. This paper also provides a step-by-step guidance to the theoretical interpretation of DST data for micellar solutions. Distributions of monomers and micelles in the vicinity of the gas/liquid interface, adsorption kinetics, and DST relaxation curves have been simulated in the framework of the Fainerman theory (Fainerman, V.B. Kolloid. Zhur. 1981, 43, 94) explicitly allowing for monomer/micelle interconversation. A thorough numerical analysis has shown that although the Fainerman theory can follow the general experimental trends, it clearly lacks the flexibility needed to provide a self-consistent and quantitatively-correct description of the process. Possible reasons for this disagreement are discussed.

  • 1414.
    Zhmud, BV
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Tiberg, F
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Kizling, J
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Long-time interfacial relaxation in aqueous butanol solutions2000In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 16, p. 7685-7690Article in journal (Refereed)
    Abstract [en]

    The long-time relaxation of the dynamic surface tension (DST) in aqueous solutions of four structural isomers of butyl alcohol has been observed with the aid of the maximum bubble pressure technique. Diffusion-controlled kinetics was found to allow an apparently successful (in terms of the quality of fitting) description of the observed DST dynamics, but it leads to an unrealistically low value of the diffusion coefficient, 10-11-10-13 m2 s-1. Conversely, the activation-controlled kinetics fails to explain the slow damping of DST curves observed over long time periods. A comprehensive theoretical analysis supported by numerical simulations has conclusively shown that neither diffusion nor mixed diffusion-activation kinetics can adequately account for the observed slower DST relaxation. As an alternative explanation, the presence of packing defects in the adsorbed layer is proposed.

  • 1415. Zhou, Q
    et al.
    Rutland, MW
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Teeri, TT
    Brumer, H
    Xyloglucan in cellulose modification2007In: Cellulose, ISSN 0969-0239, E-ISSN 1572-882X, Vol. 14, no 6, p. 625-641Article in journal (Refereed)
    Abstract [en]

    Xyloglucans are the principal polysaccharides coating and crosslinking cellulose microfibrills in the majority of land plants. This review summarizes current knowledge of xyloglucan structures, solution properties, and the mechanism of interaction of xyloglucans with cellulose. This knowledge base forms the platform for new biomimetic methods of cellulose surface modification with applications within the fields of textile manufacture, papermaking, and materials science. Recent advances using the enzyme xyloglucan endo-transglycosylase (XET, EC 2.4.1.207) to introduce varied chemical functionality onto cellulose surfaces are highlighted.

  • 1416. Zhou, Ye
    et al.
    Gorochovceva, Natalja
    Makuska, Ricardas
    Dedinaite, Andra
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Claesson, Per M
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Chitosan-N-poly(ethylene oxide) brush polymers for reduced nonspecific protein adsorption2007In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 305, p. 62-71Article in journal (Refereed)
    Abstract [en]

    The possibility of using a novel comb polymer consisting of a chitosan backbone with grafted 44 units long poly(ethylene oxide) side chains for reducing nonspecific protein adsorption to gold surfaces functionalized by COOH-terminated thiols has been explored. The comb polymer was attached to the surface in three different ways: by solution adsorption, covalent coupling, and microcontact printing. The protein repellant properties were tested by monitoring the adsorption of bovine serum albumin and fibrinogen employing surface plasmon resonance and imaging null ellipsometry. It was found that a significant reduction in protein adsorption is achieved as the comb polymer layer is sufficiently dense. For solution adsorption this was achieved by adsorption from high pH solutions. On the other hand, the best performance of the microcontact printed surfaces was obtained when the stamp was inked either at low or at high pH. For a given comb polymer layer thickness/poly(ethylene oxide) density, significant differences in protein repellant properties were observed between the different preparation methods, and it is suggested that a reduction in the mobility of the comb polymer layer generated by covalent attachment favors a reduced protein adsorption.

  • 1417. Zhu, Y
    et al.
    Olofsson, U
    Persson, Karin
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Investigation of factors influencing wheel-rail adhesion using a mini-traction machine2012In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 292-293, p. 218-231Article in journal (Refereed)
    Abstract [en]

    Adhesion in the wheel-rail contact is a key factor determining stable running conditions and safety during train driving and braking. This paper presents an experiment performed in a mini-traction machine to simulate the problems of low adhesion in the wheel-rail contact. Tests were conducted under dry conditions and using water or oil as lubricants to study the influence of surface roughness on the adhesion coefficient. The results indicate that the adhesion coefficient can be reduced to as low as 0.02 for smooth surfaces lubricated with water. For rougher contact surfaces, the water-lubricated tests indicate a higher adhesion coefficient than do oil-lubricated ones, but also a clear dependence on water temperature. The oil-lubricated tests indicate a very slight dependence of the adhesion coefficient on variation in rolling speed, temperature, and surface roughness.

  • 1418. Zimmermann, A
    et al.
    Millqvist-Fureby, Anna
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Ringkjøbing, Elema M
    Hansen, T
    Müllertz, A
    Hovgaard L,
    Adsorption of pharmaceutical excipients onto microcrystals of siramesine hydrochloride: Effects on physicochemical properties2009In: European journal of pharmaceutics and biopharmaceutics, ISSN 0939-6411, E-ISSN 1873-3441, Vol. 71, no 1, p. 109-116Article in journal (Refereed)
    Abstract [en]

    A common challenge in the development of new drug substances is poor dissolution characteristics caused by low aqueous solubility. In this study, microcrystals with optimized physicochemical properties were prepared by precipitation in the presence of excipients, which adsorbed to the particle surface and altered particle size, morphology, and dissolution rate. The poorly water-soluble drug siramesine hydrochloride was precipitated by the antisolvent method in the presence of each of various polymeric and surface active excipients. Powder dissolution studies of six of the resulting particle systems showed a significant increase in percent dissolved after 15 min compared to the starting material. A quantitative determination of the amount of excipient adsorbed to the surface of the drug particles proved that only a very small amount of excipient was needed to exert a marked effect on particle properties. The adsorbed amount of excipient constituted less than 1.4% (w/w) of the total particle weight, and thus powders of very high drug loads were obtained. Sodium lauryl sulphate (SLS), hydroxypropyl methylcellulose (HPMC), and hydroxypropyl cellulose (HPC), which exhibited the greatest degree of adsorption, also had the greatest effect on the physicochemical properties of the particles. X-ray Photoelectron Spectroscopy (XPS) analysis of the surface composition and scanning electron microscopy studies on particle morphology suggested that the excipients adsorbed to specific faces of the crystals.

  • 1419. Åmand, HL
    et al.
    Nordén, B
    Fant, K
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Functionalization with C-terminal cysteine enhances transfection efficiency of cell-penetrating peptides trough dimer formation2012In: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, E-ISSN 1090-2104, Vol. 418, no 3, p. 469-474Article in journal (Refereed)
    Abstract [en]

    Cell-penetrating peptides have the ability to stimulate uptake of macromolecular cargo in mammalian cells in a non-toxic manner and therefore hold promise as efficient and well tolerated gene delivery vectors. Non-covalent peptide-DNA complexes (" peptiplexes") enter cells via endocytosis, but poor peptiplex stability and endosomal entrapment are considered as main barriers to peptide-mediated delivery. We explore a simple, yet highly efficient, strategy to improve the function of peptide-based vectors, by adding one terminal cysteine residue. This allows the peptide to dimerize by disulfide bond formation, increasing its affinity for nucleic acids by the "chelate effect" and, when the bond is reduced intracellularly, letting the complex dissociate to deliver the nucleic acid. By introducing a single C-terminal cysteine in the classical CPP penetratin and the penetratin analogs PenArg and EB1, we show that this minor modification greatly enhances the transfection capacity for plasmid DNA in HEK293T cells. We conclude that this effect is mainly due to enhanced thermodynamic stability of the peptiplexes as endosome-disruptive chloroquine is still required for transfection and the effect is more pronounced for peptides with lower inherent DNA condensation capacity. Interestingly, for EB1, addition of one cysteine makes the peptide able to mediate transfection in absence of chloroquine, indicating that dimerisation can also improve endosomal escape properties. Further, the cytotoxicity of EB1 peptiplexes is considerably reduced, possibly due to lower concentration of free peptide dimer resulting from its stronger binding to DNA.

  • 1420. Ödberg, L
    et al.
    Forsberg, S
    McBride, G
    Persson, M
    Stenius, P
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Ström, G
    Surfactant behaviour of wood resin components.Part 2. Solubilization in micelles of rosin and fatty acids1985In: Svensk Papperstidning, ISSN 0283-6831, Vol. 88, p. R118-R125Article in journal (Refereed)
  • 1421.
    Ödberg, L
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    McBride, G
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Magnusson, KE
    Characterization of the surface of cellulosic fibers using aqueous two-phase partitioning1985In: Progress in Colloid and Polymer Science, ISSN 0340-255X, E-ISSN 1437-8027, Vol. 70, p. 109-112Article in journal (Refereed)
  • 1422. Ödberg, L
    et al.
    Ström, G
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    ESCA studies of retention and dewatering aids. The adsorption of polymin SNand polymin SN-lignosulfonate complexes on cellulose1983In: Svensk Papperstidning, ISSN 0283-6831, Vol. 86, p. R141-R145Article in journal (Refereed)
  • 1423. Östberg, G
    et al.
    Bergenståhl, B
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Emulsification of alkyds for industrial coatings1996In: JCT: Journal of Coatings Technology, ISSN 0361-8773, Vol. 68, p. 39-45Article in journal (Refereed)
    Abstract [en]

    Alkyd emulsions have so far mostly been used in consumer paints. These are relatively easy to emulsify due to their low viscosity. Lately alkyd emulsions for industrial paint have gained increasing attention. Alkyd for industrial paints have a much higher viscosity than alkyds for consumer paints which requires other emulsification techniques. In this work an alkyd with 40 % oil length have been emulsified by the inversion technique. Inversion emulsification by adding water to an alkyd/surfactant mixture at constant temperature give emulsions with droplet sizes below 1pm at a concentration of 3 % on the alkyd phase. Small droplets are necessary for colloidal stability of the emulsion. The solubility of surfactant in the alkyd and the water phase determines at which water concentration the emulsion inverts. High molecular weight ethoxylated anionic surfactants are effective as emulsifiers. Using these surfactants the emulsification becomes less dependent on emulsification temperature than when nonionic surfactants are used.

  • 1424. Östberg, G
    et al.
    Bergenståhl, B
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Mechanical stability of alkyd emulsions. Part 2: Influence of alkyd properties1994In: JCT: Journal of Coatings Technology, ISSN 0361-8773, Vol. 66, no 838, p. 37-41Article in journal (Refereed)
    Abstract [en]

    The development of water borne alkyd paints based on alkyd emulsions has been stimulated by more stringent health and environment regulations. In addition, alkyd paints may have better performance in some applications compared to other types of water -borne paints such as latex dispersions. One problem that needs to be overcome is the limited colloidal stability of alkyd emulsions. It is important that the emulsions are not destabilized when exposed to shear forces such as those produced by pumps used by the paint industry. An alkyd emulsion consist of alkyd oil droplets dispersed in water and stabilized by a surface active agent (emulsifier). Part 1 of this serie describes the influence of emulsion droplet size and type or concentration of the emulsifier on the shear stability. The present study is an additional investigation of the influence of the alkyd properties on shear stability. Increasing the acid value of the alkyd increases the stability of emulsions stabilized with nonionic emulsifiers. Emulsions made using alkyds with shorter oil lengths and higher viscosities were less stable to shear compared to alkyds with higher oil lengths and lower viscosities.

  • 1425. Östberg, G
    et al.
    Bergenståhl, B
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Huldén, M
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Influence of emulsifier on the formation of alkyd emulsions1995In: Colloids and Surfaces A: Physicochemical and Engineering Aspects, ISSN 0927-7757, E-ISSN 1873-4359, Vol. 94, p. 161-171Article in journal (Refereed)
    Abstract [en]

    In traditional alkyd paints, the alkyd is dissolved in an organic solvent such as mineral spirit. For health and environmental reasons there is an increasing interest in water-borne alkyd paints. Alkyd emulsions are therefore an interesting alternative. The alkyd emulsion should have a good colloidal stability at a low concentration of surfactant. A high concentration of surfactant gives undesired properties of the paint film, as for example water sensitivity. In this paper, the influence of emulsification temperature and emulsifier concentration on the formation of alkyd emulsions has been investigated. The temperature dependence observed with both anionic and nonionic emulsifiers is related to the change in viscosity of the alkyd with temperature. In the case of nonionic emulsifiers, an additional effect is seen due to the change in HLB (Hydrophilic Lipophilic Balance) of the surfactant with temperature. A concentration corresponding to a close packing of the non-ionic surfactant on the surface of the droplets is needed to obtain a stable emulsion when nonionic surfactants are used. In the case of anionic emulsifiers, stable emulsions can be obtained at low concentrations giving a very low packing density at the surface.

  • 1426. Östberg, G
    et al.
    Bergenståhl, B
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Huldén, M
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Mechanical stability of alkyd emulsions. Part 1: Influence of emulsion droplet size and the emulsifier1994In: JCT: Journal of Coatings Technology, ISSN 0361-8773, Vol. 66, no 832, p. 37-46Article in journal (Refereed)
    Abstract [en]

    The limited colloidal stability of alkyd emulsions compared to that of organic solvent-borne alkyd paints is a well known problem. For environmental reasons, however, they have a great advantage since they are water-borne. In this study, we have investigated the influence of emulsifier and initial droplet size on the mechanical stability of alkyd emulsions. Anionic emulsifiers have previously been shown to be more effective than nonionic emulsifiers in the formation of alkyd emulsions. Here it has been found that an anionic emulsifier also gave more stable emulsions at lower concentrations than did the nonionics. Emulsions stabilized with a nonionic emulsifier showed the same stability as the one with the anionic emulsifiers if the concentration was increased. Too high a concentration of surfactants is undesirable in paints, however, since it increases the water sensitivity of the paint film. The mechanical stability of anionically stabilized emulsions was less sensitive to the initial droplet size compared to emulsions stabilized with a nonionic emulsifier.

  • 1427. Östberg, G
    et al.
    Bergenståhl, B
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Sörenssen, K
    Distribution of driers between the alkyd and aqueous phase in alkyd emulsions and its relation to drying properties1992In: JCT: Journal of Coatings Technology, ISSN 0361-8773, Vol. 64, no 814, p. 33-43Article in journal (Refereed)
    Abstract [en]

    The influence of pH, emulsifiers and alkyd properties on the distribution of driers between the alkyd- and water phase in alkyd emulsions has been studied. When the pH in the emulsion is decreased, cobalt and calcium driers are redistributed towards the water phase. However, zirconium was found to remain in the alkyd phase independent of pH. Hydrophilic anionic emulsifiers were found to decrease the amount of cobalt and calcium driers in the alkyd phase. The distribution is not influenced by alkyd properties such as oil length or acid values. The relation between the distribution of driers and drying properties has also been investigated. The results indicate a correlation between the early drying rate and cobalt concentration in the alkyd phase.

  • 1428. Östberg, G
    et al.
    Huldén, M
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Bergenståhl, B
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Holmberg, K
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Alkyd emulsions1994In: Progress in organic coatings, ISSN 0300-9440, E-ISSN 1873-331X, Vol. 24, p. 281-297Article in journal (Refereed)
    Abstract [en]

    Various aspects of alkyd emulsion technology have been investigated. Firstly, the influence of alkyd oil length, acid value and hydroxyl number, as well as the type of surfactant used as emulsifier, on shear stability of alkyds emulsions have been studied. It was found that the acid value was the most important alkyd parameter, the stability increasing with increasing oil length. It is also shown that anionic surfactants give emulsions with small droplet sizes down at lower concentrations than nonionics. Secondly, polymerizable nonionic surfactants have been tested as emulsifiers and compared with conventional surfactants of the same HLB. It was found that surfactants capable of participating in the autoxidative curing process give faster drying and improved film hardness compared with non-reactive surfactants. Thirdly, the distribution of driers between the alkyd phase and the water phase has been investigated. It was found that low pH and the use of hydrophilic anionic surfactants, such as SDS, favour partitioning of cobalt into the aqueous phase which is unfavourable with respect to drying properties.

  • 1429. Österberg, E
    et al.
    Bergström, K
    Holmberg, K
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Riggs, JA
    Van Alstine, JM
    Schuman, TP
    Comparison of polysaccharide and poly(ethylene glycol) coatings for reduction of protein adsorption on polystyrene surfaces1993In: Colloids and Surfaces A: Physicochemical and Engineering Aspects, ISSN 0927-7757, E-ISSN 1873-4359, Vol. 77, p. 159-169Article in journal (Refereed)
    Abstract [en]

    There has been much recent interest in the use of poly(ethylene glycol)s (PEGs) for a variety of biotechnical applications. In the present work we have immobilized several cellulose derivatives and dextran on polystyrene surfaces and have measured the extent of fibrinogen adsorption onto the coated surfaces. Immobilization was achieved by adsorption onto clean polystyrene and by covalent linkage of oxidized polysaccharides to polyethylenimine which was ionically bound to polystyrene. Covalently bound polysaccharides. and adsorbed polysaccharides that are strongly held, compare well with poly(ethylene glycol) in preventing fibrinogen adsorption. The same polymers were coupled to polystyrene latex particles to permit examination by analytical microparticle electrophoresis. This investigation suggests that adsorbed polysaccharides form thicker layers than do covalently bound polysaccharides. Despite the polysaccharides being bound at many points along the polymer chain while PEG is bound only at the polymer terminus, the functional equivalence of polysaccharide and PEG coatings is of significance in interpreting the protein-rejecting ability of polymer-modified surfaces.

  • 1430.
    Österberg, M
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Claesson, PM
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Interactions between cellulose surfaces: Effect of solution pH2000In: Journal of Adhesion Science and Technology, ISSN 0169-4243, E-ISSN 1568-5616, Vol. 14, p. 603-618Article in journal (Refereed)
    Abstract [en]

    The forces acting between cellulose surfaces have been studied using the interferometric surface force apparatus. The cellulose surfaces were prepared by Langmuir-Blodgett deposition of trimethylsilyl cellulose (TMSC) onto hydrophobised mica. Prior to measurements the surfaces were desilylated to obtain pure cellulose. The degree of silylation and the molecular weight of the TMSC both affect the structure of the deposited layer. This was observed from the surface pressure/area isotherm, force versus distance curves and atomic force microscopy images. The forces between the cellulose surfaces were found to depend on the pH of the solution. In dilute electrolyte solutions the cellulose film was uncharged and rather compact when the pH of the solution was 6.0. However, when the pH was increased to 7.3 the cellulose film swelled considerably and a long-range steric force was measured. The swelling of the film is interpreted as being due to dissociation of a few carboxylic acid groups present along the cellulose chain. The forces measured were, however, dominated by steric interactions. The repulsion does not increase substantially when the pH is increased from 7.3 to 9.5. Our results suggest that the pKa of the acid groups present within the cellulose film is larger than it would be in bulk aqueous solution.

  • 1431.
    Österberg, M
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Laine, J
    Stenius, P
    Kumpulainen, A
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Claesson, PM
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Forces between xylan-coated surfaces: Effect of polymer charge density and background electrolyte2001In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 242, p. 59-66Article in journal (Refereed)
  • 1432. Östmark, E
    et al.
    Macakova, L
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Auletta, T
    Malkoch, M
    Malmström, E
    Blomberg, E
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Dendritic structures based on bis(hydroxymethyl)propionic acid as platforms for surface reactions2005In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 21, p. 4512-4519Article in journal (Refereed)
    Abstract [en]

    In this paper we present results related to the self-assembly of different generations of disulphide-cored 2,2-bis-(methylol)propionic acid-based dendritic structures onto gold surfaces. These molecular architectures, ranging from generation 1 (G#1) to generation 3 (G#3), contain removable acetonide protecting groups at their periphery that are accessible for hydrolysis with subsequent formation of OH-terminated surface-attached dendrons. The deprotection has been investigated in detail as a versatile approach to accomplish reactive surface platforms. A special focus has been devoted to the comparison of the properties of the layers formed by hydrolysis of the acetonide moieties directly on the surface and in solution, prior to the layer formation.

26272829 1401 - 1432 of 1432
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