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Sample records for content oil-external micellar

  1. Protein, casein and micellar salts in milk: Current content and historical perspectives

    NARCIS (Netherlands)

    Bijl, E.; Valenberg, van H.J.F.; Huppertz, T.; Hooijdonk, van A.C.M.

    2013-01-01

    The protein and fat content of Dutch bulk milk has been monitored since the 1950s and has increased considerably, by 11 and 20%, respectively, whereas milk yield has more than doubled. The change in protein and fat content of milk is advantageous for the dairy industry, as these are the 2 most

  2. Highly Sensitive Micellar Enhanced Spectrofluorimetric Method for Determination of Mirtazapine in Tablets and Human Urine: Application to In Vitro Drug Release and Content Uniformity Test

    Directory of Open Access Journals (Sweden)

    Hany W. Darwish

    2016-01-01

    Full Text Available A highly sensitive and simple micelle enhanced spectrofluorimetric method was developed for assaying mirtazapine (MRZ in REMERON® tablets and spiked human urine directly without the need of derivatizing agent. The basis of the current procedure is the examination of the relative fluorescence intensity (RFI of MRZ in sodium lauryl sulphate (SLS micellar medium. The RFI of MRZ in water was enhanced markedly on addition of SLS. The RFI was measured at 403 nm after excitation at 320 nm. The fluorescence-concentration relationship was linear over the range 1–500 ng/mL, with lower detection limit of 0.399 ng/mL. The proposed method was successfully applied to the determination of MRZ in dosage form and spiked human urine. Recovery percentages of MRZ utilizing the current method were 99.05±1.83, 98.37±1.96, and 100.41±2.61% for pure powder, pharmaceutical dosage form, and spiked human urine, respectively. The application of the proposed method was extended to test content uniformity and the in vitro drug release of REMERON tablets, according to USP guidelines.

  3. Enhanced Micellar Catalysis LDRD.

    Energy Technology Data Exchange (ETDEWEB)

    Betty, Rita G.; Tucker, Mark D; Taggart, Gretchen; Kinnan, Mark K.; Glen, Crystal Chanea; Rivera, Danielle; Sanchez, Andres; Alam, Todd Michael

    2012-12-01

    The primary goals of the Enhanced Micellar Catalysis project were to gain an understanding of the micellar environment of DF-200, or similar liquid CBW surfactant-based decontaminants, as well as characterize the aerosolized DF-200 droplet distribution and droplet chemistry under baseline ITW rotary atomization conditions. Micellar characterization of limited surfactant solutions was performed externally through the collection and measurement of Small Angle X-Ray Scattering (SAXS) images and Cryo-Transmission Electron Microscopy (cryo-TEM) images. Micellar characterization was performed externally at the University of Minnesotas Characterization Facility Center, and at the Argonne National Laboratory Advanced Photon Source facility. A micellar diffusion study was conducted internally at Sandia to measure diffusion constants of surfactants over a concentration range, to estimate the effective micelle diameter, to determine the impact of individual components to the micellar environment in solution, and the impact of combined components to surfactant phase behavior. Aerosolized DF-200 sprays were characterized for particle size and distribution and limited chemical composition. Evaporation rates of aerosolized DF-200 sprays were estimated under a set of baseline ITW nozzle test system parameters.

  4. Micellar liquid chromatography

    International Nuclear Information System (INIS)

    Basova, Elena M; Ivanov, Vadim M; Shpigun, Oleg A

    1999-01-01

    Background and possibilities of practical applications of micellar liquid chromatography (MLC) are considered. Various retention models in MLC, the effects of the nature and concentration of surfactants and organic modifiers, pH, temperature and ionic strength on the MLC efficiency and selectivity are discussed. The advantages and limitations of MLC are demonstrated. The performance of MLC is critically evaluated in relationship to the reversed-phase HPLC and ion-pair chromatography. The potential of application of MLC for the analysis of pharmaceuticals including that in biological fluids and separation of inorganic anions, transition metal cations, metal chelates and heteropoly compounds is described. The bibliography includes 146 references.

  5. Impact of thermooxidation of phytosteryl and phytostanyl fatty acid esters on cholesterol micellarization in vitro.

    Science.gov (United States)

    Scholz, Birgit; Weiherer, Renate; Engel, Karl-Heinz

    2017-09-01

    The effects of thermooxidation of a phytosteryl/-stanyl and a phytostanyl fatty acid ester mixture on cholesterol micellarization were investigated using an in vitro digestion model simulating enzymatic hydrolysis by cholesterol esterase and subsequent competition of the liberated phytosterols/-stanols with cholesterol for incorporation into mixed micelles. As a first step, relationships between different doses of the ester mixtures and the resulting micellarized cholesterol were established. Subsequent subjection of the thermooxidized ester mixtures to the in vitro digestion model resulted in three principal observations: (i) thermal treatment of the ester mixtures led to substantial decreases of the intact esters, (ii) in vitro digestion of cholesterol in the presence of the thermooxidized ester mixtures resulted in significant increases of cholesterol micellarization, and (iii) the extents of the observed effects on cholesterol micellarization were strongly associated to the remaining contents of intact esters. The loss of efficacy to inhibit cholesterol micellarization due to thermally induced losses of intact esters corresponded to a loss of efficacy that would have been induced by an actual removal of these amounts of esters prior to the in vitro digestion. The obtained results suggest that in particular oxidative modifications of the fatty acid moieties might be responsible for the observed increases of cholesterol micellarization. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Pressure-induced melting of micellar crystal

    DEFF Research Database (Denmark)

    Mortensen, K.; Schwahn, D.; Janssen, S.

    1993-01-01

    that pressure improves the solvent quality of water, thus resulting in decomposition of the micelles and consequent melting of the micellar crystal. The combined pressure and temperature dependence reveals that in spite of the apparent increase of order on the 100 angstrom length scale upon increasing......Aqueous solutions of triblock copolymers of poly(ethylene oxide) and poly(propylene oxide) aggregate at elevated temperatures into micelles which for polymer concentrations greater-than-or-equal-to 20% make a hard sphere crystallization to a cubic micellar crystal. Structural studies show...... temperature (decreasing pressure) the overall entropy increases through the inverted micellar crystallization characteristic....

  7. Catalysis in micellar and macromoleular systems

    CERN Document Server

    Fendler, Janos

    1975-01-01

    Catalysis in Micellar and Macromolecular Systems provides a comprehensive monograph on the catalyses elicited by aqueous and nonaqueous micelles, synthetic and naturally occurring polymers, and phase-transfer catalysts. It delineates the principles involved in designing appropriate catalytic systems throughout. Additionally, an attempt has been made to tabulate the available data exhaustively. The book discusses the preparation and purification of surfactants; the physical and chemical properties of surfactants and micelles; solubilization in aqueous micellar systems; and the principles of

  8. Phase separation in living micellar networks

    Science.gov (United States)

    Cristobal, G.; Rouch, J.; Curély, J.; Panizza, P.

    We present a lattice model based on two n→0 spin vectors, capable of treating the thermodynamics of living networks in micellar solutions at any surfactant concentration. We establish an isomorphism between the coupling constants in the two spin vector Hamiltonian and the surfactant energies involved in the micellar situation. Solving this Hamiltonian in the mean-field approximation allows one to calculate osmotic pressure, aggregation number, free end and cross-link densities at any surfactant concentration. We derive a phase diagram, including changes in topology such as the transition between spheres and rods and between saturated and unsaturated networks. A phase separation can be found between a saturated network and a dilute solution composed of long flexible micelles or a saturated network and a solution of spherical micelles.

  9. Vertical structures in vibrated wormlike micellar solutions

    Science.gov (United States)

    Epstein, Tamir; Deegan, Robert

    2008-11-01

    Vertically vibrated shear thickening particulate suspensions can support a free-standing interfaces oriented parallel to gravity. We find that shear thickening worm-like micellar solutions also support such vertical interfaces. Above a threshold in acceleration, the solution spontaneously accumulates into a labyrinthine pattern characterized by a well-defined vertical edge. The formation of vertical structures is of interest because they are unique to shear-thickening fluids, and they indicate the existence of an unknown stress bearing mechanism.

  10. Surface dynamics of micellar diblock copolymer films

    Science.gov (United States)

    Song, Sanghoon; Cha, Wonsuk; Kim, Hyunjung; Jiang, Zhang; Narayanan, Suresh

    2011-03-01

    We studied the structure and surface dynamics of poly(styrene)-b-poly(dimethylsiloxane) (PS-b-PDMS) diblock copolymer films with micellar PDMS surrounded by PS shells. By `in-situ' high resolution synchrotron x-ray reflectivity and diffuse scattering, we obtained exact thickness, electron density and surface tension. A segregation layer near the top surface was appeared with increasing temperature Surface dynamics were measured as a function of film thickness and temperature by x-ray photon correlation spectroscopy. The best fit to relaxation time constants as a function of in-plane wavevectors were analyzed with a theory based on capillary waves with hydrodynamics with bilayer model Finally the viscosities for the top segregated layer as well as for the bottom layer are obtained at given temperatures This work was supported by National Research Foundation of Korea (R15-2008-006-01001-0), Seoul Research and Business Development Program (10816), and Sogang University Research Grant (2010).

  11. Photonics of dyes molecules in reverse micellar solution

    International Nuclear Information System (INIS)

    Ibragimova, M.R.; Laurinas, V.Ch.

    2001-01-01

    Spectral luminescent characteristics of the dye acridine orange and eosin has been studied in reverse micellar solutions of sodium bis(2-ethyl-hexyl)sulfosuccinate. It was shown that the increase of the nucleus volume of reverse micelles. (author)

  12. Glutathione transferase mimics : Micellar catalysis of an enzymic reaction

    NARCIS (Netherlands)

    Lindkvist, Björn; Weinander, Rolf; Engman, Lars; Koetse, Marc; Engberts, Jan B.F.N.; Morgenstern, Ralf

    1997-01-01

    Substances that mimic the enzyme action of glutathione transferases (which serve in detoxification) are described. These micellar catalysts enhance the reaction rate between thiols and activated halogenated nitroarenes as well as alpha,beta-unsaturated carbonyls. The nucleophilic aromatic

  13. Biological activity and photostability of biflorin micellar nanostructures.

    Science.gov (United States)

    Santana, Edson R B; Ferreira-Neto, João P; Yara, Ricardo; Sena, Kêsia X F R; Fontes, Adriana; Lima, Cláudia S A

    2015-05-13

    Capraria biflora L. is a shrub from the Scrophulariaceae family which produces in its roots a compound named biflorin, an o-naphthoquinone that shows activity against Gram-positive bacteria and fungi and also presents antitumor and antimetastatic activities. However, biflorin is hydrophobic and photosensitive. These properties make its application difficult. In this work we prepared biflorin micellar nanostructures looking for a more effective vehiculation and better preservation of the biological activity. Biflorin was obtained, purified and characterized by UV-Vis, infrared (IR) and 1H- and 13C-NMR. Micellar nanostructures of biflorin were then assembled with Tween 80®, Tween 20® and saline (0.9%) and characterized by UV-Vis spectroscopy and dynamic light scattering (DLS). The results showed that the micellar nanostructures were stable and presented an average size of 8.3 nm. Biflorin micellar nanostructures' photodegradation was evaluated in comparison with biflorin in ethanol. Results showed that the biflorin in micellar nanostructures was better protected from light than biflorin dissolved in ethanol, and also indicated that biflorin in micelles were efficient against Gram-positive bacteria and yeast species. In conclusion, the results showed that the micellar nanostructures could ensure the maintenance of the biological activity of biflorin, conferring photoprotection. Moreover, biflorin vehiculation in aqueous media was improved, favoring its applicability in biological systems.

  14. Biological Activity and Photostability of Biflorin Micellar Nanostructures

    Directory of Open Access Journals (Sweden)

    Edson R. B. Santana

    2015-05-01

    Full Text Available Capraria biflora L. is a shrub from the Scrophulariaceae family which produces in its roots a compound named biflorin, an o-naphthoquinone that shows activity against Gram-positive bacteria and fungi and also presents antitumor and antimetastatic activities. However, biflorin is hydrophobic and photosensitive. These properties make its application difficult. In this work we prepared biflorin micellar nanostructures looking for a more effective vehiculation and better preservation of the biological activity. Biflorin was obtained, purified and characterized by UV-Vis, infrared (IR and 1H- and 13C-NMR. Micellar nanostructures of biflorin were then assembled with Tween 80®, Tween 20® and saline (0.9% and characterized by UV-Vis spectroscopy and dynamic light scattering (DLS. The results showed that the micellar nanostructures were stable and presented an average size of 8.3 nm. Biflorin micellar nanostructures’ photodegradation was evaluated in comparison with biflorin in ethanol. Results showed that the biflorin in micellar nanostructures was better protected from light than biflorin dissolved in ethanol, and also indicated that biflorin in micelles were efficient against Gram-positive bacteria and yeast species. In conclusion, the results showed that the micellar nanostructures could ensure the maintenance of the biological activity of biflorin, conferring photoprotection. Moreover, biflorin vehiculation in aqueous media was improved, favoring its applicability in biological systems.

  15. Influence of micellar calcium and phosphorus on rennet coagulation properties of cows milk.

    Science.gov (United States)

    Malacarne, Massimo; Franceschi, Piero; Formaggioni, Paolo; Sandri, Sandro; Mariani, Primo; Summer, Andrea

    2014-05-01

    The main requirement for milk processed in most cheese typologies is its rennet coagulation ability. Despite the increasing number of studies, the causes for abnormal coagulation of milk are not fully understood. The aim of this study was to ascertain relationships between milk characteristics and its rennet coagulation ability, focusing on the influence of calcium (Ca) and phosphorus (P). Ca and P are essential constituents of the micelles. Micellar P can be present as part of colloidal calcium phosphate (inorganic-P) or covalently bound to caseins as phosphate groups (casein-P). Eighty one herd milk samples (SCCproperties. Optimal milk was characterised by the highest contents of major constituents, protein fractions and minerals, lowest content of chloride and highest values of titratable acidity. Non-coagulating milk was characterised by the highest values of pH and the lowest of titratable acidity. At micellar level, Optimal milk showed the highest values of colloidal Ca, casein-P and colloidal Mg (g/100 g casein), while Non-coagulating milk showed the lowest values. Interestingly, there was no statistical difference regarding the content of colloidal inorganic-P (g/100 g casein) between Optimal and Non-coagulating milks. Overall, high mineralisation of the micelle (expressed as g inorganic-P/100 g casein) positively affect its rennetability. However, excessive mineralisation could lead to a reduction of the phosphate groups (g casein-P/100 g casein) available for curd formation.

  16. Content

    DEFF Research Database (Denmark)

    Keiding, Tina Bering

    secondary levels. In subject matter didactics, the question of content is more developed, but it is still mostly confined to teaching on lower levels. As for higher education didactics, discussions on selection of content are almost non-existent on the programmatic level. Nevertheless, teachers are forced...... curriculum, in higher education, and to generate analytical categories and criteria for selection of content, which can be used for systematic didactical reflection. The larger project also concerns reflection on and clarification of the concept of content, including the relation between content at the level......Aim, content and methods are fundamental categories of both theoretical and practical general didactics. A quick glance in recent pedagogical literature on higher education, however, reveals a strong preoccupation with methods, i.e. how teaching should be organized socially (Biggs & Tang, 2007...

  17. Ascorbyl radical disproportionation in reverse micellar systems

    Science.gov (United States)

    Gębicki, J. L.; Szymańska-Owczarek, M.; Pacholczyk-Sienicka, B.; Jankowski, S.

    2018-04-01

    Ascorbyl radical was generated by the pulse radiolysis method and observed with the fast kinetic spectrophotometry within reverse micelles stabilized by AOT in n-heptane or by Igepal CO-520 in cyclohexane at different water to surfactant molar ratio, w0. Rate constants for the disproportionation of the ascorbyl radicals were smaller than those for intermicellar exchange for both type of reverse micelles and slower than those in homogeneous aqueous solutions. However, they increased with increasing w0 for AOT/n-heptane system, while they decreased for Igepal CO-520 system. The absorption spectra of ascorbic acid AOT/n-heptane reverse micellar system showed that the "pH" sensed by this molecule is lower than that in respective homogeneous aqueous solutions. The obtained results were rationalized taking into account three main factors (i) preferential location of ascorbic acid molecules in the interfacial region of the both types of reverse micelles; (ii) postulate that the pH of the interface is lower than that of the water pool of reverse micelles and (iii) different structure of the interface of the reverse micelles made by AOT in n-heptane and those formed by Igepal CO-520 I cyclohexane. Some possible consequences of these findings are discussed.

  18. Recirculation and reutilization of micellar bile lecithin.

    Science.gov (United States)

    Robins, S J

    1975-09-01

    Bile lecithins, solubilized in micellar bile salt and radiolabeled in the 1-acyl fatty acid, phosphorus, and choline positions, were infused in the small bowel of fasted rats. Absorption of each label was virtually complete after 24 h. However, these lecithins were extensively hydrolyzed in the bowel lumen as well as after absorption, and neither the fatty acid nor phosphorus was significantly retained in the enterohepatic circulation or reutilized for biliary lecithin synthesis. In contrast, while choline was also dissociated from absorbed lecithin, choline was instead retained in the liver, reincorporated into newly synthesized hepatic lecithin, and sercreted in biliary lecithin in 10-fold greater amounts than either the fatty acid or phosphorus. However, the extent of choline incorporation into bile lecithin was limited and was not further increased when free choline was directly injected into the portal vein. The data therefore suggest that although only choline of absorbed lecithin is retained in the enterohepatic circulation and preserved for new biliary lecithin synthesis, exogenous choline utilization is regulated by the size of the available hepatic pool.

  19. Structural study of concentrated micellar solutions

    International Nuclear Information System (INIS)

    Zemb, Thomas

    1985-01-01

    This research thesis reports the study of the structure of concentrated soap-water binary micelles with a comparison of measurements of light, neutrons and X-ray scattering, and the relaxation induced by paramagnetic ions adsorbed at the interface. In the first part, the author discusses the specific sensitivity ranges of different experimental techniques, outlines the resolution which can be obtained with scattering experiments, and proposes a critical analysis of results published in the relevant literature. In a second part, the author discusses the compared results of the application of various techniques (magnetic resonance, X-light and neutron scattering) on the two most used model systems: sodium octanoate and sodium dodecyl sulfate (SDS) in solution. Then, the author addresses the case of ternary systems: study of the influence of the presence of a co-surfactant on the structure, study of the effect of interfacial charge on the micellar structure, use of the same previous quantitative methods to study the disturbances brought to the structure due to the presence of reactants [fr

  20. Principles of Micellar Electrokinetic Capillary Chromatography Applied in Pharmaceutical Analysis

    Directory of Open Access Journals (Sweden)

    Árpád Gyéresi

    2013-02-01

    Full Text Available Since its introduction capillary electrophoresis has shown great potential in areas where electrophoretic techniques have rarely been used before, including here the analysis of pharmaceutical substances. The large majority of pharmaceutical substances are neutral from electrophoretic point of view, consequently separations by the classic capillary zone electrophoresis; where separation is based on the differences between the own electrophoretic mobilities of the analytes; are hard to achieve. Micellar electrokinetic capillary chromatography, a hybrid method that combines chromatographic and electrophoretic separation principles, extends the applicability of capillary electrophoretic methods to neutral analytes. In micellar electrokinetic capillary chromatography, surfactants are added to the buffer solution in concentration above their critical micellar concentrations, consequently micelles are formed; micelles that undergo electrophoretic migration like any other charged particle. The separation is based on the differential partitioning of an analyte between the two-phase system: the mobile aqueous phase and micellar pseudostationary phase. The present paper aims to summarize the basic aspects regarding separation principles and practical applications of micellar electrokinetic capillary chromatography, with particular attention to those relevant in pharmaceutical analysis.

  1. Ordering fluctuations in a shear-banding wormlike micellar system

    DEFF Research Database (Denmark)

    Angelico, R.; Rossi, C. Oliviero; Ambrosone, L.

    2010-01-01

    We present a first investigation about the non-linear flow properties and transient orientational-order fluctuations observed in the shear-thinning lecithin–water–cyclohexane wormlike micellar system at a concentration near to the zero-shear isotropic–nematic phase transition. From rheological...

  2. Strip waves in vibrated shear-thickening wormlike micellar solutions

    Science.gov (United States)

    Epstein, T.; Deegan, R. D.

    2010-06-01

    We present an instability in vertically vibrated dilute wormlike micellar solutions. Above a critical driving acceleration the fluid forms elongated solitary domains of high amplitude waves. We model this instability using a Mathieu equation modified to account for the non-Newtonian character of the fluid. We find that our model successfully reproduces the observed transitions.

  3. Rheological Properties of Hydrophobically Associative Copolymers Prepared in a Mixed Micellar Method Based on Methacryloxyethyl-dimethyl Cetyl Ammonium Chloride as Surfmer

    Directory of Open Access Journals (Sweden)

    Rui Liu

    2014-01-01

    Full Text Available A novel cationic surfmer, methacryloxyethyl-dimethyl cetyl ammonium chloride (DMDCC, is synthesized. The micellar properties, including critical micelle concentration and aggregation number, of DMDCC-SDS mixed micelle system are studied using conductivity measurement and a steady-state fluorescence technique. A series of water-soluble associative copolymers with acrylamide and DMDCC are prepared using the mixed micellar polymerization. Compared to conventional micellar polymerization, this new method could not only reasonably adjust the length of the hydrophobic microblock, that is, NH, but also sharply reduce the amount of surfactant. Their rheological properties related to hydrophobic microblock and stickers are studied by the combination of steady flow and linear viscoelasticity experiments. The results indicate that both the hydrophobic content and, especially the length of the hydrophobic microblock are the dominating factors effecting the intermolecular hydrophobic association. The presence of salt influences the dynamics of copolymers, resulting in the variation of solution characters. Viscosity measurement indicates that mixed micelles between the copolymer chain and SDS molecules serving as junction bridges for transitional network remarkably enhance the viscosity. Moreover, the microscopic structures of copolymers at different experimental conditions are conducted by ESEM. This method gives us an insight into the preparation of hydrophobically associative water-soluble copolymers by cationic surfmer-anionic surfactant mixed micellar polymerization with good performance.

  4. Contents

    Directory of Open Access Journals (Sweden)

    Editor IJRED

    2012-11-01

    Full Text Available International Journal of Renewable Energy Development www.ijred.com Volume 1             Number 3            October 2012                ISSN 2252- 4940   CONTENTS OF ARTICLES page Design and Economic Analysis of a Photovoltaic System: A Case Study 65-73 C.O.C. Oko , E.O. Diemuodeke, N.F. Omunakwe, and E. Nnamdi     Development of Formaldehyde Adsorption using Modified Activated Carbon – A Review 75-80 W.D.P Rengga , M. Sudibandriyo and M. Nasikin     Process Optimization for Ethyl Ester Production in Fixed Bed Reactor Using Calcium Oxide Impregnated Palm Shell Activated Carbon (CaO/PSAC 81-86 A. Buasri , B. Ksapabutr, M. Panapoy and N. Chaiyut     Wind Resource Assessment in Abadan Airport in Iran 87-97 Mojtaba Nedaei       The Energy Processing by Power Electronics and its Impact on Power Quality 99-105 J. E. Rocha and B. W. D. C. Sanchez       First Aspect of Conventional Power System Assessment for High Wind Power Plants Penetration 107-113 A. Merzic , M. Music, and M. Rascic   Experimental Study on the Production of Karanja Oil Methyl Ester and Its Effect on Diesel Engine 115-122 N. Shrivastava,  , S.N. Varma and M. Pandey  

  5. Micellar enhanced spectrofluorimetric methods: application to the determination of pyrene

    Energy Technology Data Exchange (ETDEWEB)

    Singh, H.; Hinze, W.L.

    1982-01-01

    The effects of cationic hexadecyltrimethylammonium chloride (CTAC), nonionic polyoxyethylene(9.5)p-1,1,3,3-tetramethylbutylphenol, Triton X-100 (TX-100), and anionic sodium dodecylsulfate (NaLS) surfactant micelles upon the spectrofluorimetric determination of pyrene is described. It was found that the intensity of the pyrene fluorescence is enhanced from 3 to 16 times in the presence of the micellar systems. Possible reasons for this micellar induced enhanced fluorescence are discussed. The spectral parameters, fluorescence lifetimes, quantum yields, lower detection limits, and analytical figures of merit for pyrene in CTAC, NaLS, TX-100, ethanol, and water are compared. The detection limit of pyrene in the presence of micelles (approx. 1.0 x 10/sup -10/ M) is about an order of magnitude lower than that possible in alcohol alone. A brief discussion on the predicted general applicability of this new technique in fluorimetric analysis is also given. 4 figures, 2 tables.

  6. Pyrene absorption can be a convenient method for probing critical micellar concentration (cmc) and indexing micellar polarity.

    Science.gov (United States)

    Basu Ray, Gargi; Chakraborty, Indranil; Moulik, Satya P

    2006-02-01

    The critical micellar concentration (cmc) of both ionic and non-ionic surfactants can be conveniently determined from the measurements of UV absorption of pyrene in surfactant solution. The results on a number of surfactants have agreed with that realized from pyrene fluorescence measurements as well as that obtained following conductometric, tensiometric and calorimetric methods. The absorbance vs [surfactant] profiles for all the major UV spectral peaks of pyrene have been found to be sigmoidal in nature which were analyzed according to Sigmoidal-Boltzmann equation (SBE) to evaluate the cmcs of the studied surfactants. The difference between the initial and the final asymptotes (a(i) and a(f), respectively) of the sigmoidal profile, Delta a = (a(f)-a(i)) and the slope of the sigmoid, S(sig) have been observed to depend on the type of the surfactant. The Delta a has shown a linear correlation with the ratio of the fluorescence intensities of the first and the third vibronic peaks, I1/I3 of pyrene which is considered as a measure of the environmental polarity (herein micellar interior) of the probe (pyrene). Thus, Delta a values have the prospect for use as another index for the estimation of polarity of micellar interior.

  7. Micellar Catalysis of Diels-Alder Reactions : Substrate Positioning in the Micelle

    NARCIS (Netherlands)

    Rispens, Theo; Engberts, Jan B.F.N.

    2002-01-01

    We have studied the kinetics of the Diels-Alder reactions of cyclopentadiene, sorbyl alcohol, and sorbyltrimethylammonium bromide with a series of N-substituted maleimides in micellar media. Micellar rate constants have been determined and were found to be 20-40 times lower than the respective

  8. One electron reduction of acridine orange studied in aqueous micellar medium using pulse radiolysis technique

    International Nuclear Information System (INIS)

    Goel, Anjali; Guha, S.N.

    1994-01-01

    Absorption spectrum, decay and formation kinetics of semi reduced species formed by the reaction of hydrated electron (e aq - ) with acridine orange (AO) were evaluated in sodium lauryl sulphate (SLS) micellar medium. Fluorescence and absorption properties of AO were also studied in this micellar system. The results were compared with those in homogenous aqueous medium. (author). 2 refs., 2 figs

  9. Technical note: Development and validation of a new method for the quantification of soluble and micellar calcium, magnesium, and potassium in milk.

    Science.gov (United States)

    Franzoi, M; Niero, G; Penasa, M; Cassandro, M; De Marchi, M

    2018-03-01

    Milk mineral content is a key trait for its role in dairy processes such as cheese-making, its use as source of minerals for newborns, and for all traits involving salt-protein interactions. This study investigated a new method for measuring mineral partition between soluble and micellar fractions in bovine milk after rennet coagulation. A new whey dilution step was added to correct the quantification bias due to whey trapped in curd and excluded volume. Moreover, the proposed method allowed the quantification of the diffusible volume after milk coagulation. Milk mineral content and concentration in whey, and diluted whey were quantified by acid digestion and inductively coupled plasma optical emission spectrometry. The repeatability of the method for micellar Ca, Mg, and K was between 2.07 and 8.96%, whereas reproducibility ranged from 4.01 to 9.44%. Recovery of total milk minerals over 3 spiking levels ranged from 92 to 97%. The proposed method provided an accurate estimation of micellar and soluble minerals in milk, and curd diffusible volume. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  10. Marginalism, quasi-marginalism and critical phenomena in micellar solutions

    International Nuclear Information System (INIS)

    Reatto, L.

    1986-01-01

    The observed nonuniversal critical behaviour of some micellar solutions is interpreted in terms of quasi-marginalism, i.e. the presence of a coupling which scales with an exponent very close to the spatial dimensionality. This can give rise to a preasymptotic region with varying effective critical exponents with a final crossover to the Ising ones. The reduced crossover temperature is estimated to be below 10 -6 . The exponents β and γ measured in C 12 e 5 are in good agreement with the scaling law expected to hold for the effective exponents. The model considered by Shnidman is found unable to explain the nonuniversal critical behaviour

  11. Differential thermodynamic signature of carbon nanomaterials using amphiphilic micellar probe

    Science.gov (United States)

    Bhattacharyya, Tamoghna; Dasgupta, Anjan Kr

    2018-04-01

    The thermodynamic signature of single-wall carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs) and reduced graphene oxide (rG-O) using amphiphilic micellar probe has been explored. The study reveals an intricate correlation between nano-surface topology and calorimetric profile of SWCNTs, MWCNTs and rG-O. The critical micelle concentration (CMC) is found to be sensitive to the topological diversity of nanomaterials. The study explores a thermodynamic approach to characterize the nano-surface topology of SWCNTs, MWCNTs and graphene surface.

  12. Organisation and shape of micellar solutions of block copolymers

    Science.gov (United States)

    Gaspard, J. P.; Creutz, S.; Bouchat, Ph.; Jérôme, R.; Cohen Stuart, M.

    1997-02-01

    Diblock copolymers of polymethacrylic acid sodium salt, forming the hair, and styrene derivatives have been studied in aqueous solutions by SANS and SAXS. The influence of both the chemical nature and the length of the hydrophobic bloxk on the size and shape of micelles have been investigated. The micellar core size is in agreement with the theoretical evaluation for copolymers with a short hydrophobic sequence. In contrast, in case of larger hydrophobic blocks, the measured size is incompatible with a star-like model. Various hypotheses are presented for the latter.

  13. Preparation of PEO/Clay Nanocomposites Using Organoclay Produced via Micellar Adsorption of CTAB

    Science.gov (United States)

    Gürses, Ahmet; Ejder-Korucu, Mehtap; Doğar, Çetin

    2012-01-01

    The aim of this study was the preparation of polyethylene oxide (PEO)/clay nanocomposites using organoclay produced via micellar adsorption of cethyltrimethyl ammonium bromide (CTAB) and their characterisation by X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectra, and the investigation of certain mechanical properties of the composites. The results show that the basal distance between the layers increased with the increasing CTAB/clay ratio as parallel with the zeta potential values of particles. By considering the aggregation number of CTAB micelles and interlayer distances of organo-clay, it could be suggested that the predominant micelle geometry at lower CTAB/clay ratios is an ellipsoidal oblate, whereas, at higher CTAB/clay ratios, sphere-ellipsoid transition occurs. The increasing tendency of the exfoliation degree with an increase in clay content may be attributed to easier diffusion of PEO chains to interlayer regions. FT-IR spectra show that the intensity of Si-O stretching vibrations of the organoclays (1050 cm−1) increased, especially in the ratios of 1.0 g/g clay and 1.5 g/g clay with the increasing CTAB content. It was observed that the mechanical properties of the composites are dependent on both the CTAB/clay ratios and clay content of the composites. PMID:23365515

  14. Modulated photophysics of 2-anthracene sulphonate in micellar assembly

    International Nuclear Information System (INIS)

    Rana, Dipak Kumar; Sarkar, Arindam; Dhar, Sayaree; Mandal, Tapas Kumar; Bhattacharya, Subhash Chandra

    2010-01-01

    The association of a non-ionic surfactant of polyoxyethylene-p-(1,1,3,3-tetramethylbutyl)phenyl ether (Triton X) series with 2-AS in aqueous solution has been studied by means of steady-state, time-resolved fluorescence and fluorescence anisotropy techniques. The effect of the hydrophobic chain length on the structural dynamism of the fluorophore has been reported. Experimental results demonstrate that the equilibrium of this dynamism is sensitive to the environment. The association constant of the probe molecule with the non-ionic micelles of Triton X (TX), location of the probe in the micellar environment, have been determined from the change in emission characteristics of the probe as a function of surfactant concentration. The rate constant of quenching and mode of quenching of probe in micellar media have been ascertained. Quantitative estimates of the micropolarity at the binding sites of the probe molecule have been determined. Some of the environment-dependent relevant fluorescence parameters, fluorescence anisotropy (r), have been monitored for exploring the imposed motional restriction of the microenvironment around the probe. An attempt has been made to correlate the steady-state results with time resolved study.

  15. Two-phase aqueous micellar systems: an alternative method for protein purification

    Directory of Open Access Journals (Sweden)

    Rangel-Yagui C. O.

    2004-01-01

    Full Text Available Two-phase aqueous micellar systems can be exploited in separation science for the extraction/purification of desired biomolecules. This article reviews recent experimental and theoretical work by Blankschtein and co-workers on the use of two-phase aqueous micellar systems for the separation of hydrophilic proteins. The experimental partitioning behavior of the enzyme glucose-6-phosphate dehydrogenase (G6PD in two-phase aqueous micellar systems is also reviewed and new results are presented. Specifically, we discuss very recent work on the purification of G6PD using: i a two-phase aqueous micellar system composed of the nonionic surfactant n-decyl tetra(ethylene oxide (C10E4, and (ii a two-phase aqueous mixed micellar system composed of C10E4 and the cationic surfactant decyltrimethylammonium bromide (C10TAB. Our results indicate that the two-phase aqueous mixed (C10E4/C10TAB micellar system can improve significantly the partitioning behavior of G6PD relative to that observed in the two-phase aqueous C10E4 micellar system.

  16. A theory of phase separation in asphaltene-micellar solutions

    Energy Technology Data Exchange (ETDEWEB)

    Pacheco Sanchez, Juan H. [Instituto Mexicano del Petroleo, Mexico D.F. (Mexico)

    2001-08-01

    A theory of phase separation in micellar solutions of asphaltene in aromatic hydrocarbons was reported in this paper, based on both the approach of the phase behavior of amphiphile/water micelles, and the self-association of asphaltene in aromatic core. Several experimental techniques have been used by different investigators showing the existence of some kind of critical micellar concentration (CMC) on asphaltenes in aromatic solutions. So, at least asphaltene-monomer and asphaltene-micellar phases are experimentally demonstrated facts. These two phases are the main purpose in this report on a theoretical model. Some results show the temperature versus asphaltene concentration phase diagram. The phase diagram is examined against the limited critical micelle concentration data for asphaltenes-in-toluene systems. Such phase diagram is also qualitatively examined against an experimental demonstration of phase separation. The asphaltene-micelle growth depends on the parameter K responsible for the shape and size of it. At the same time, parameter K depends on both the number of asphaltene-monomer associated in the asphaltene-micelle, and the chemical potentials in the interior and in the periphery of the micelle. An expression for getting the number of asphaltene-monomers self-associated in the asphaltene-micelle was obtained. [Spanish] Se reporta una teoria de separacion de fases en soluciones micelares de asfalteno en hidrocarburos aromaticos, basada tanto en la conducta de fase de micelas formadas por anififilos en agua como en la autoasociacion de asfaltenos en nucleos aromaticos. Se han usado diversas tecnicas experimentales por diferentes investigadores que demuestran la existancia de algun tipo de concentracion micelar critica (CMC) de soluciones de asfaltenos en aromaticos. Entonces, al menos las fases de asfalteno-monomerico y de asfalteno-micelar son hechos experimentalmente demostrados. Esta dos fases son el principal proposito de este reporte en un modelo

  17. Removal of Pyrethrin from Aqueous Effluents by Adsorptive Micellar Flocculation

    Directory of Open Access Journals (Sweden)

    Pardon K. Kuipa

    2015-01-01

    Full Text Available The equilibrium adsorption of pyrethrin onto aggregates formed by the flocculation of micelles of the surfactant sodium dodecyl sulphate (SDS with aluminium sulphate is reported. The experimental results were analysed using different adsorption isotherms (Langmuir, Freundlich, Redlich-Peterson, Sips, Radke-Prausnitz, Temkin, linear equilibrium, and the Dubin-Radushkevich isotherms. The Freundlich and linear equilibrium isotherms best describe the adsorption of pyrethrin onto SDS micellar flocs, with the Freundlich adsorption constant, KF, and the mass distribution coefficient, KD, of 64.266 ((mg/g(L/mg1/n and 119.65 L/g, respectively. Applicability of the Freundlich adsorption model suggests that heterogeneous surface adsorption affects the adsorption. The mean free energy value estimated using the Dubinin-Radushkevich isotherm was 0.136 kJ/mol indicating that physisorption may be predominant in the adsorption process.

  18. Micellar phase boundaries under the influence of ethyl alcohol

    International Nuclear Information System (INIS)

    Bergeron, Denis E.

    2016-01-01

    The Compton spectrum quenching technique is used to monitor the effect of ethyl alcohol (EtOH) additions on phase boundaries in two systems. In toluenic solutions of the nonionic surfactant, Triton X-100, EtOH shifts the boundary separating the first clear phase from the first turbid phase to higher water:surfactant ratios. In a commonly used scintillant, Ultima Gold AB, the critical micelle concentration is not shifted. The molecular interactions behind the observations and implications for liquid scintillation counting are discussed. - Highlights: • Compton spectrum quenching technique applied to find micellar phase boundaries. • Toluenic Triton X-100 and Ultima Gold AB investigated. • Ethyl alcohol affects phase boundaries in Triton X-100, not in Ultima Gold AB. • Phase boundary observations discussed in terms of relevant molecular interactions.

  19. Micellar polymerization: Computer simulations by dissipative particle dynamics.

    Science.gov (United States)

    Shupanov, Ruslan; Chertovich, Alexander; Kos, Pavel

    2018-07-15

    Nowadays, micellar polymerization is widely used in different fields of industry and research, including modern living polymerization technique. However, this process has many variables and there is no comprehensive model to describe all features. This research presents simulation methodology which describes key properties of such reactions to take a guide through a variety of their modifications. Dissipative particle dynamics is used in addition to Monte Carlo scheme to simulate initiation, propagation, and termination events. Influence of initiation probability and different termination processes on final conversion and molecular-weight distribution are presented. We demonstrate that prolonged initiation leads to increasing in polymer average molecular weight, and surface termination events play major role in conversion limitation, in comparison with recombination. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

  20. SANS study of three-layer micellar particles

    CERN Document Server

    Plestil, J; Kuklin, A I; Cubitt, R

    2002-01-01

    Three-layer nanoparticles were prepared by polymerization of methyl methacrylate (MMA) in aqueous micellar solutions of poly(methyl methacrylate)-block-poly(methacrylic acid) (PMMA-b-PMA) and polystyrene-block-poly(methacrylic acid) (PS-b-PMA). The resulting polymer forms a layer on the core surface of the original micelles. SANS curves were fitted using an ellipsoidal (PMMA/PMMA/PMA) or spherical (PS/PMMA/PMA) model for the particle core. The particle size (for the presented series of the PMMA/PMMA/PMA particles, the core semiaxes ranged from 87 to 187 A and the axis ratio was about 6) can be finely tuned by variation of monomer concentration. Time-resolved SANS experiments were carried out to describe the growth of the PS/PMMA/PMA particles during polymerization. (orig.)

  1. Radiation decomposition of alcohols and chloro phenols in micellar systems

    International Nuclear Information System (INIS)

    Moreno A, J.

    1998-01-01

    The effect of surfactants on the radiation decomposition yield of alcohols and chloro phenols has been studied with gamma doses of 2, 3, and 5 KGy. These compounds were used as typical pollutants in waste water, and the effect of the water solubility, chemical structure, and the nature of the surfactant, anionic or cationic, was studied. The results show that anionic surfactant like sodium dodecylsulfate (SDS), improve the radiation decomposition yield of ortho-chloro phenol, while cationic surfactant like cetyl trimethylammonium chloride (CTAC), improve the radiation decomposition yield of butyl alcohol. A similar behavior is expected for those alcohols with water solubility close to the studied ones. Surfactant concentrations below critical micellar concentration (CMC), inhibited radiation decomposition for both types of alcohols. However radiation decomposition yield increased when surfactant concentrations were bigger than the CMC. Aromatic alcohols decomposition was more marked than for linear alcohols decomposition. On a mixture of alcohols and chloro phenols in aqueous solution the radiation decomposition yield decreased with increasing surfactant concentration. Nevertheless, there were competitive reactions between the alcohols, surfactants dimers, hydroxyl radical and other reactive species formed on water radiolysis, producing a catalytic positive effect in the decomposition of alcohols. Chemical structure and the number of carbons were not important factors in the radiation decomposition. When an alcohol like ortho-chloro phenol contained an additional chlorine atom, the decomposition of this compound was almost constant. In conclusion the micellar effect depend on both, the nature of the surfactant (anionic or cationic) and the chemical structure of the alcohols. The results of this study are useful for wastewater treatment plants based on the oxidant effect of the hydroxyl radical, like in advanced oxidation processes, or in combined treatment such as

  2. Jet A fuel recovery using micellar flooding: Design and implementation.

    Science.gov (United States)

    Kostarelos, Konstantinos; Lenschow, Søren R; Stylianou, Marinos A; de Blanc, Phillip C; Mygind, Mette Marie; Christensen, Anders G

    2016-09-01

    Surfactants offer two mechanisms for recovering NAPLs: 1) to mobilize NAPL by reducing NAPL/water interfacial tension, and; 2) to increase the NAPL's aqueous solubility-called solubilization-as an enhancement to pump & treat. The second approach has been well-studied and applied successfully in several pilot-scale and a few full-scale tests within the last 15years, known as Surfactant Enhanced Aquifer Remediation (SEAR). A useful source of information for this second approach is the "Surfactant-enhanced aquifer remediation (SEAR) design manual" from the U.S. Navy Facilities Engineering Command. Few attempts, however, have been made at recovering NAPLs using the mobilization approach presented in this paper. Now, a full-scale field implementation of the mobilization approach is planned to recover an LNAPL (Jet A fuel) from a surficial sand aquifer located in Denmark using a smaller amount of surfactant solution and fewer PVs of throughput compared with the SEAR approach. The approach will rely on mobilizing the LNAPL so that it is recovered ahead of the surfactant microemulsion, also known as a micellar flood. This paper will review the laboratory work performed as part of the design for a full-scale implementation of a micellar flood. Completed lab work includes screening of surfactants, phase behavior and detailed salinity scans of the most promising formulations, and generating a ternary diagram to be used for the numerical simulations of the field application. The site owners and regulators were able to make crucial decisions such as the anticipated field results based on this work. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Phase behavior and micellar properties of carboxylic acid end group modified pluronic surfactants

    NARCIS (Netherlands)

    Custers, J.P.A.; Broeke, van den L.J.P.; Keurentjes, J.T.F.

    2007-01-01

    The micellar behavior of three different carboxylic acid end standing (CAE) surfactants has been characterized using conductometry, differential scanning calorimetry, isothermal titration calorimetry, and dynamic light scattering. The CAE surfactants are modified high molecular weight Pluronic

  4. Amplification of Chirality through Self-Replication of Micellar Aggregates in Water

    KAUST Repository

    Bukhriakov, Konstantin; Almahdali, Sarah; Rodionov, Valentin

    2015-01-01

    We describe a system in which the self-replication of micellar aggregates results in a spontaneous amplification of chirality in the reaction products. In this system, amphiphiles are synthesized from two "clickable" fragments: a water-soluble "head

  5. Effect of calcium chelators on physical changes in casein micelles in concentrated micellar casein solutions

    NARCIS (Netherlands)

    Kort, de E.J.P.; Minor, M.; Snoeren, T.H.M.; Hooijdonk, van A.C.M.; Linden, van der E.

    2011-01-01

    The effect of calcium chelators on physical changes of casein micelles in concentrated micellar casein solutions was investigated by measuring calcium-ion activity, viscosity and turbidity, and performing ultracentrifugation. The highest viscosities were measured on addition of sodium

  6. Effect of the interaction of heat-processing style and fat type on the micellarization of lipid-soluble pigments from green and red pungent peppers (Capsicum annuum).

    Science.gov (United States)

    Victoria-Campos, Claudia I; Ornelas-Paz, José de Jesús; Yahia, Elhadi M; Failla, Mark L

    2013-04-17

    The high diversity of carotenoids and chlorophylls in foods contrasts with the reduced number of pigments that typically are investigated in micellarization studies. In this study, pepper samples (raw and heat-treated) contained 68 individual pigments, but only 38 of them were micellarized after in vitro digestion. The micellarization of pigments was majorly determined by the interaction effect of processing style (food matrix effect) and fat type (saturated and unsaturated). The highest micellarization was observed with raw peppers. Unsaturated fat increased the micellarization of carotenoid esters, while the impact of fat on the micellarization of free carotenoids seemed to be dependent on pigment structure. The micellarization efficiency was diminished as the esterification level of carotenoids increased. The type of fatty acid moiety and the polarity of the carotenoids modulated their micellarization. Chlorophylls were transformed into pheophytins by heat-processing and digestion, with the pheophytins being stable under gastrointestinal conditions. Micellarization of pheophytins was improved by fat.

  7. Redox reactions in micellar systems. communication 4. Eosin-photosensitized reduction of methylviologen

    Energy Technology Data Exchange (ETDEWEB)

    Nadtochenko, V.; Dzhabiev, T.S.; Rubtsov, I.V.

    1985-12-10

    The authors present data on photosensitized reduction of methylviologen (MV/sup 2 +/) by disodium ethylenediaminetetraacetate (EDTA) in micellar systems modeling, in a first approximation, the structural organization of components of the chain of energy and electron transfer in natural photosynthesis. Photosensitized reduction of methylviologen by EDTA in micellar solutions can model photosystem I of plants with structure formation of reagents and transfer of excitation energy before the step of occurrence of a redox reaction in the active center.

  8. Simple micellar electrokinetic chromatography method for the determination of hydrogen sulfide in hen tissues.

    Science.gov (United States)

    Kubalczyk, Paweł; Borowczyk, Kamila; Chwatko, Grażyna; Głowacki, Rafał

    2015-04-01

    A new method for the determination of hydrogen sulfide in hen tissues has been developed and validated. For estimation of hydrogen sulfide content, a sample (0.1 g) of hen tissue was treated according to the procedure consisted of some essential steps: simultaneous homogenization of a tissue and derivatization of hydrogen sulfide to its S-quinolinium derivative with 2-chloro-1-methylquinolinium tetrafluoroborate, separation of so-formed derivative by micellar electrokinetic chromatography with sweeping, and detection and quantitation with the use of UV detector set to measure analytical signals at 375 nm. Effective electrophoretic separation was achieved using fused silica capillary (effective length 41.5 cm, 75 μm id) and 0.05 mol/L, pH 8 phosphate buffer with the addition of 0.04 mol/L SDS and 26% ACN. The lower limit of quantification was 0.12 μmol hydrogen sulfide in 1 g of tissue. The calibration curve prepared in tissue homogenate for hydrogen sulfide showed linearity in the range from 0.15 to 2.0 μmol/g, with the coefficient of correlation 0.9978. The relative standard deviation of the points of the calibration curve varied from 8.3 to 3.2% RSD. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Online naphazoline quality control by micellar-enhanced spectrofluorimetry.

    Science.gov (United States)

    Peralta, Cecilia Mariana; Silva, Raúl Alejandro; Fernández, Liliana Patricia; Masi, Adriana Noemí

    2011-01-01

    The aim of this study was to develop a method for online spectrofluorimetric quality control of naphazoline (NPZ) in pharmaceuticals and raw drugs. A combination of a flow-injection analysis (FIA) system with micellar-enhanced fluorescence detection is presented as a powerful alternative for the rapid and sensitive analysis of naphazoline. Since NPZ shows low native fluorescence, the use of an anionic surfactant, such as sodium dodecyl sulphate (SDS), provides a considerable enhancement of fluorescence intensity and the nature of the technique allows a possible and easy adaptation to a FIA system. Using λ(exc) = 280 nm and λ(em) = 326 nm, a good linear relationship (LOL) was obtained in the range 0.003-10 µg mL(-1) with a detection limit (LOD) of 3 × 10(-4) µg mL(-1) (s/n = 3). Parameters related to the nature of the analytical signal and to the FIA manifold were optimized. Satisfactory recoveries were obtained in the analysis of commercial pharmaceutical formulations. The proposed method is simple, accurate and allows for high-speed sampling and considerably shorter analysis times. In addition, it requires inexpensive equipment and reagents and has easy operational conditions and no side effects, thus avoiding environmental pollution through toxic waste. Copyright © 2011 John Wiley & Sons, Ltd.

  10. Micellar electrokinetic chromatographic determination of triazine herbicides in water samples.

    Science.gov (United States)

    Li, Zhi; Zhang, Shuaihua; Yin, Xiaofang; Wang, Chun; Wang, Zhi

    2014-09-01

    Dispersive liquid-liquid microextraction combined with online sweeping preconcentration in micellar electrokinetic chromatography was developed for the simultaneous determination of five triazine herbicides (atrazine, simazine, propazine, prometon and simetryn) in water samples. Several experimental parameters affecting the extraction efficiencies such as the type and volume of both the extraction and dispersive solvents, the addition of salt to sample solution, the extraction time and the pH of the sample solution were investigated. Under optimum conditions, the linearity of the method was good in the range from 0.33 to 20 ng mL(-1) for simazine, propazine, atrazine and simetryn, and from 0.17 to 20 ng mL(-1) for prometon, respectively. The sensitivity enrichment factors were in the range from 1750 to 2100, depending on the compound. The limit of detection (S/N = 3) ranged from 0.05 to 0.10 ng mL(-1). The developed method was successfully applied to the analysis of the five triazines in river, ground and well waters. © The Author [2013]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. PH-triggered micellar membrane for controlled release microchips

    KAUST Repository

    Yang, Xiaoqiang

    2011-01-01

    A pH-responsive membrane based on polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) block copolymer was developed on a model glass microchip as a promising controlled polymer delivery system. The PS-b-P4VP copolymer assembles into spherical and/or worm-like micelles with styrene block cores and pyridine coronas in selective solvents. The self-assembled worm-like morphology exhibited pH-responsive behaviour due to the protonation of the P4VP block at low pH and it\\'s deprotonation at high pH and thus constituting a switchable "off/on" system. Doxorubicin (Dox) was used as cargo to test the PS-b-P4VP membrane. Luminescence experiments indicated that the membrane was able to store Dox molecules within its micellar structure at neutral pH and then release them as soon as the pH was raised to 8.0. The performance of the cast membrane was predictable and most importantly reproducible. The physiochemical and biological properties were also investigated carefully in terms of morphology, cell viability and cell uptake. This journal is © The Royal Society of Chemistry.

  12. Separation Of N-Nitrosamines By Micellar Electrokinetic Chromatography

    International Nuclear Information System (INIS)

    Nur Amira Md Ali; Mohd Marsin Sanagi; Wan Aini Wan Ibrahim

    2014-01-01

    A simple and rapid micellar electrokinetic chromatography (MEKC) method was developed for separation of three selected N-Nitrosamines namely N-nitrosodipropylamine (NDPA), N-nitrosodibutylamine (NDBA) and N-nitrosodiphenylamine (NDPhA). The effects of composition of the buffer and its pH, concentration of surfactants on the separation and migration times of nitrosamines were investigated. The instrumental variables affecting sensitivity and resolution such as power supply and injection mode were carefully optimized. The best separation was achieved using 40 mM sodium dodecyl sulfate (SDS) as a surfactant in 10 mM phosphate buffer (pH 8.0) at a temperature of 25 degree Celsius, applied voltage of 29 kV, wavelength of 230 nm and electrokinetic injection of 9 s at 5 kV within 10 min analysis time. Excellent linearity was obtained in the concentration range of 2 to 100 μg/ mL with coefficients of determination, r 2 ≥0.979. This method showed good reproducibility with relative standard deviation (RSDs) value ranging from 2.46 % to 6.61 %. The limits of detection (LOD) and limits of quantification (LOQ) ranged from 0.16 to 0.43 μg/ mL and 0.54 to 1.44 μg/mL respectively. (author)

  13. Octane-Assisted Reverse Micellar Dyeing of Cotton with Reactive Dyes

    Directory of Open Access Journals (Sweden)

    Alan Yiu-lun Tang

    2017-12-01

    Full Text Available In this study, we investigated the computer colour matching (CCM of cotton fabrics dyed with reactive dye using the octane-assisted reverse micellar approach. The aim of this study is to evaluate the colour quality and compare the accuracy between CCM forecasting and simulated dyeing produced by conventional water-based dyeing and octane-assisted reverse micellar dyeing. First, the calibration of dyeing databases for both dyeing methods was established. Standard samples were dyed with known dye concentrations. Computer colour matching was conducted by using the colour difference formula of International Commission on Illumination (CIE L*a*b*. Experimental results revealed that the predicted concentrations were nearly the same as the expected known concentrations for both dyeing methods. This indicates that octane-assisted reverse micellar dyeing system can achieve colour matching as good as the conventional water-based dyeing system. In addition, when comparing the colour produced by the conventional water-based dyeing system and the octane-assisted reverse micellar dyeing system, the colour difference (ΔE is ≤1, which indicates that the reverse micellar dyeing system could be applied for industrial dyeing with CCM.

  14. Study of the Reaction 2-(p-Nitrophenylethyl Bromide + OH− in Dimeric Micellar Solutions

    Directory of Open Access Journals (Sweden)

    María Luisa Moyá

    2011-11-01

    Full Text Available The dehydrobromination reaction 2-(p-nitrophenylethyl bromide + OH− was investigated in several alkanediyl-a-w-bis(dodecyldimethylammonium bromide, 12-s-12,2Br− (with s = 2, 3, 4, 5, 6, 8, 10, 12 micellar solutions, in the presence of NaOH 5 × 10−3 M. The kinetic data were quantitatively rationalized within the whole surfactant concentration range by using an equation based on the pseudophase ion-exchange model and taking the variations in the micellar ionization degree caused by the morphological transitions into account. The agreement between the theoretical and the experimental data was good in all the dimeric micellar media studied, except for the 12-2-12,2Br− micellar solutions. In this case, the strong tendency to micellar growth shown by the 12-2-12,2Br− micelles could be responsible for the lack of accordance. Results showed that the dimeric micelles accelerate the reaction more than two orders of magnitude as compared to water.

  15. Selection of reservoirs amenable to micellar flooding. First annual report, October 1978-December 1979

    Energy Technology Data Exchange (ETDEWEB)

    Goldburg, A.; Price, H.

    1980-12-01

    The overall project objective is to build a solid engineering base upon which the Department of Energy (DOE) can improve and accelerate the application of micellar-polymer recovery technology to Mid-Continent and California sandstone reservoirs. The purpose of the work carried out under these two contracts is to significantly aid, both DOE and the private sector, in gaining the following Project Objectives: to select the better micellar-polymer prospects in the Mid-Continent and California regions; to assess all of the available field and laboratory data which has a bearing on recovering oil by micellar-polymer projects in order to help identify and resolve both the technical and economic constraints relating thereto; and to design and analyze improved field pilots and tests and to develop a micellar-polymer applications matrix for use by the potential technology users; i.e., owner/operators. The report includes the following: executive summary and project objectives; development of a predictive model for economic evaluation of reservoirs; reservoir data bank for micellar-polymer recovery evaluation; PECON program for preliminary economic evaluation; ordering of candidate reservoirs for additional data acquisition; validation of predictive model by numerical simulation; and work forecast. Tables, figures and references are included.

  16. A simplified radiometabolite analysis procedure for PET radioligands using a solid phase extraction with micellar medium

    International Nuclear Information System (INIS)

    Nakao, Ryuji; Halldin, Christer

    2013-01-01

    A solid phase extraction method has been developed for simple and high-speed direct determination of PET radioligands in plasma. Methods: This methodology makes use of a micellar medium and a solid-phase extraction cartridge for displacement of plasma protein bound radioligand and separation of PET radioligands from their radiometabolites without significant preparation. The plasma samples taken from monkey or human during PET measurements were mixed with a micellar eluent containing an anionic surfactant sodium dodecyl sulphate and loaded onto SPE cartridges. The amount of radioactivity corresponding to parent radioligand (retained on the cartridge) and its radioactive metabolites (eluted with micellar eluent) was measured. Results: Under the optimized conditions, excellent separation of target PET radioligands from their radiometabolites was achieved with a single elution and short run-time of 1 min. This method was successfully applied to study the metabolism for 11 C-labelled radioligands in human or monkey plasma. The amount of parent PET radioligands estimated by micellar solid phase extraction strongly corresponded with that determined by radio-LC. The improved throughput permitted the analysis of a large number of plasma samples (up to 13 samples per one PET study) for accurate estimation of metabolite-corrected input function during quantitative PET imaging studies. Conclusion: Solid phase extraction together with micellar medium is fast, sensitive and easy to use, and therefore it is an attractive alternative method to determine relative composition of PET radioligands in plasma

  17. Production efficiency of micellar casein concentrate using polymeric spiral-wound microfiltration membranes.

    Science.gov (United States)

    Beckman, S L; Zulewska, J; Newbold, M; Barbano, D M

    2010-10-01

    Most current research has focused on using ceramic microfiltration (MF) membranes for micellar casein concentrate production, but little research has focused on the use of polymeric spiral-wound (SW) MF membranes. A method for the production of a serum protein (SP)-reduced micellar casein concentrate using SW MF was compared with a ceramic MF membrane. Pasteurized (79°C, 18s) skim milk (1,100 kg) was microfiltered at 50°C [about 3 × concentration] using a 0.3-μm polyvinylidene fluoride spiral-wound membrane, bleed-and-feed, 3-stage process, using 2 diafiltration stages, where the retentate was diluted 1:2 with reverse osmosis water. Skim milk, permeate, and retentate were analyzed for SP content, and the reduction of SP from skim milk was determined. Theoretically, 68% of the SP content of skim milk can be removed using a single-stage 3× MF. If 2 subsequent water diafiltration stages are used, an additional 22% and 7% of the SP can be removed, respectively, giving a total SP removal of 97%. Removal of SP greater than 95% has been achieved using a 0.1-μm pore size ceramic uniform transmembrane pressure (UTP) MF membrane after a 3-stage MF with diafiltration process. One stage of MF plus 2 stages of diafiltration of 50°C skim milk using a polyvinylidene fluoride polymeric SW 0.3-μm membrane yielded a total SP reduction of only 70.3% (stages 1, 2, and 3: 38.6, 20.8, and 10.9%, respectively). The SP removal rate for the polymeric SW MF membrane was lower in all 3 stages of processing (stages 1, 2, and 3: 0.05, 0.04, and 0.03 kg/m(2) per hour, respectively) than that of the comparable ceramic UTP MF membrane (stages 1, 2, and 3: 0.30, 0.11, and 0.06 kg/m(2) per hour, respectively), indicating that SW MF is less efficient at removing SP from 50°C skim milk than the ceramic UTP system. To estimate the number of steps required for the SW system to reach 95% SP removal, the third-stage SP removal rate (27.4% of the starting material SP content) was used to

  18. The magnetoviscous effect of micellar solutions doped with water based ferrofluids

    Energy Technology Data Exchange (ETDEWEB)

    Arantes, Fabiana R., E-mail: farantes@if.usp.br [Institute of Physics, University of Sao Paulo (Brazil); Institute of Fluid Mechanics, Technische Universität Dresden (Germany); Odenbach, Stefan, E-mail: stefan.odenbach@tu-dresden.de [Institute of Fluid Mechanics, Technische Universität Dresden (Germany)

    2015-09-15

    This work presents a magnetorheological study of micellar solutions of potassium laurate and water doped with magnetite nanoparticles, accompanied by auxiliary dynamic light scattering measurements. An increase in the viscosity of the samples under applied field was observed and, furthermore, a considerable magnetoviscous effect was revealed even at magnetic particles' concentrations as low as 0.005–0.01 vol%. This indicates that the rheological behavior of the micelles is changed by the interaction of the magnetic particles with the applied field, leading to different microscopic arrangements in the micellar solutions. - Highlights: • We study the magnetorheological behavior of micellar solutions doped with ferrofluids. • We observe an increase in the viscosity of the samples under an applied field. • We find a large magnetoviscous effect even at low magnetic particles' concentration. • Interaction of particles with the field changes the micelles' rheological behavior.

  19. Energy transfer from triplet aromatic hydrocarbons to Tb3+ and Eu3+ in aqueous micellar solutions

    International Nuclear Information System (INIS)

    Almgren, M.; Grieser, F.; Thomas, J.K.

    1979-01-01

    The sensitization of Tb 3+ and Eu 3+ luminescence by energy transfer from aromatic triplet donors like naphthalene, bromonaphthalene, biphenyl, and phenanthrene in micellar sodium lauryl sulfate solution has been studied. Formal second-order rate constants for the energy transfer process in the micellar solutions were determined as 5 x 10 5 and 1.8 x 10 5 M -1 S -1 for transfer from biphenyl to Tb 3+ . The method of converting these rate constants to second-order constants pertaining to the micellar microenvironment is discussed; it is estimated that the transfer process at the micelles is charaterized by rate constants about one order of magnitude smaller than the formal ones. The transfer process is thus extremely slow. 7 figures

  20. Molecular organization and dynamics of micellar phase of polyelectrolyte-surfactant complexes: ESR spin probe study

    Science.gov (United States)

    Wasserman, A. M.; Kasaikin, V. A.; Zakharova, Yu. A.; Aliev, I. I.; Baranovsky, V. Yu.; Doseva, V.; Yasina, L. L.

    2002-04-01

    Molecular dynamics and organization of the micellar phase of complexes of linear polyelectrolytes with ionogenic and non-ionogenic surfactants was studied by the ESR spin probe method. Complexes of polyacrylic acid (PAA) and sodium polystyrenesulfonate (PSS) with alkyltrimethylammonium bromides (ATAB), as well as complexes of poly- N, N'-dimethyldiallylammonium chloride (PDACL) with sodium dodecylsulfate (SDS) were studied. The micellar phase of such complexes is highly organized molecular system, molecular ordering of which near the polymeric chain is much higher than in the 'center' of the micelle, it depends on the polymer-detergent interaction, flexibility of polymeric chain and length of carbonic part of the detergent molecule. Complexes of polymethacrylic acid (PMAA) with non-ionic detergent (dodecyl-substituted polyethyleneglycol), show that the local mobility of surfactant in such complexes is significantly lower than in 'free' micelles and depends on the number of micellar particles participating in formation of complexes.

  1. Au/CdS Hybrid Nanoparticles in Block Copolymer Micellar Shells.

    Science.gov (United States)

    Koh, Haeng-Deog; Changez, Mohammad; Lee, Jae-Suk

    2010-10-18

    A polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) micellar structure with a P2VP core containing 5 nm CdS nanoparticles (NPs) and a PS shell formed in toluene that is a good solvent for PS block undergoes the core-shell inversion by excess addition of methanol that is a good solvent for P2VP block. It leads to the formation of micellar shell-embedded CdS NPs in the methanol major phase. The spontaneous crystalline growth of Au NPs on the CdS surfaces positioned at micellar shells without a further reduction process is newly demonstrated. The nanostructure of Au/CdS/PS-b-P2VP hybrid NPs is confirmed by transmission electron microscopy, energy-dispersive X-ray, and UV-Vis absorption. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Molecular motion of micellar solutes: a 13C NMR relaxation study

    International Nuclear Information System (INIS)

    Stark, R.E.; Kasakevich, M.L.; Granger, J.W.

    1982-01-01

    A series of simple NMR relaxation experiments have been performed on nitrobenzene and aniline dissolved in the ionic detergents sodium dodecyl sulfate (SDS) and hexadecyltrimethylammonium bromide (CTAB). Using 13 C relaxation rates at various molecular sites, and comparing data obtained in organic media with those for micellar solutions, the viscosity at the solubilization site was estimated and a detailed picture of motional restrictions imposed by the micellar enviroment was derived. Viscosities of 8 to 17 cp indicate a rather fluid environment for solubilized nitrobenzene; both additives exhibit altered motional preferences in CTAB solutions only. As an aid in interpretation of the NMR data, quasi-elastic light scattering and other physical techniques have been used to evaluate the influence of organic solutes on micellar size and shape. The NMR methods are examined critically in terms of their general usefulness for studies of solubilization in detergent micelles. 48 references

  3. Effect of ripening, heat processing, and fat type on the micellarization of pigments from jalapeño peppers.

    Science.gov (United States)

    Victoria-Campos, Claudia I; Ornelas-Paz, José de Jesús; Yahia, Elhadi M; Jiménez-Castro, Jorge A; Cervantes-Paz, Braulio; Ibarra-Junquera, Vrani; Pérez-Martínez, Jaime David; Zamudio-Flores, Paul B; Escalante-Minakata, Pilar

    2013-10-16

    Raw and heat-processed (boiled and grilled) jalapeño peppers at three intermediate ripening stages (brown, 50% red, and 75% red) were digested in vitro without fat and in the presence of soybean oil (SO) or beef tallow (BT), and the micellarization of their lipid soluble pigments (LSP) was measured. The micelles from digestions with brown, 50% red, and 75% red peppers contained up to 27, 35, and 29 different LSP, respectively. Boiling and grilling decreased the micellarization of LSP from brown peppers, whereas the opposite was observed with 75% red peppers. Heat processing did not clearly affect the micellarization of LSP from 50% red fruits. The impact of fat on LSP micellarization was ripening-dependent, but the micellarization of the less polar carotenoids was always increased by SO or BT. This positive effect of fat was higher with SO than with BT.

  4. Modification of silica surface by gamma ray induced Ad micellar Polymerization

    International Nuclear Information System (INIS)

    Buathong, Salukjit; Pongprayoon, Thirawudh; Suwanmala, Phiriyatorn

    2005-10-01

    Precipitated silica is often added to natural rubber compounds in order to improve performance in commercial application. A problem with using silica as filler is the poor compatibility between silica and natural rubber. In this research, polyisoprene was coated on silica surface by gamma ray induced ad micellar polymerization in order to achieve the better compatibility between silica and natural rubber. The modified silica was characterized by FT-IR, and SEM. The results show that polyisoprene was successfully coated on silica surface via gamma ray induced ad micellar polymerization

  5. Micellar aggregates of saponins from Chenopodium quinoa: characterization by dynamic light scattering and transmission electron microscopy.

    Science.gov (United States)

    Verza, S G; de Resende, P E; Kaiser, S; Quirici, L; Teixeira, H F; Gosmann, G; Ferreira, F; Ortega, G G

    2012-04-01

    Entire seeds of Chenopodium quinoa Willd are a rich protein source and are also well-known for their high saponin content. Due to their amphiphily quinoa saponins are able to form intricate micellar aggregates in aqueous media. In this paper we study the aggregates formed by self-association of these compounds from two quinoa saponin fractions (FQ70 and FQ90) as well as several distinctive nanostructures obtained after their complexation with different ratios of cholesterol (CHOL) and phosphatidylcholine (PC). The FQ70 and FQ90 fractions were obtained by reversed-phase preparative chromatography. The structural features of their resulting aggregates were determined by Dynamic Light Scattering (DLS) and Transmission Electron Microscopy (TEM). Novel nanosized spherical vesicles formed by self-association with mean diameter about 100-200 nm were observed in FQ70 aqueous solutions whereas worm-like micelles an approximate width of 20 nm were detected in FQ90 aqueous solutions. Under experimental conditions similar to those reported for the preparation of Quillaja saponaria ISCOM matrices, tubular and ring-like micelles arose from FQ70:CHOL:PC and FQ90:CHOL:PC formulations, respectively. However, under these conditions no cage-like ISCOM matrices were observed. The saponin composition of FQ70 and FQ90 seems to determine the nanosized structures viewed by TEM. Phytolaccagenic acid, predominant in FQ70 and FQ90 fractions, is accountable for the formation of the nanosized vesicles and tubular structures observed by TEM in the aqueous solutions of both samples. Conversely, ring-like micelles observed in FQ90:CHOL:PC complexes can be attributed to the presence of less polar saponins present in FQ90, in particular those derived from oleanolic acid.

  6. phenylalanine and l-tyrosine as chiral micellar media for the cat

    African Journals Online (AJOL)

    potential chiral micellar catalysts for the Diels-Alder reaction between methyl acrylate and .... hydrophobic effects, electrostatic interactions and the accompanying medium effects. In the case .... liquids as effective organocatalysts for Diels-Alder reaction. Green Chem. 2014, 16 .... Colloids and Surfaces A: Physicochem.

  7. phenylalanine and l-tyrosine as chiral micellar media for the cat

    African Journals Online (AJOL)

    polar solvents [15-18]. Hence, surfactants offer the possibility for organic reactions to occur in aqueous media, and from the viewpoint of green chemistry, water is safer, harmless and environmentally benign [19]. However, there has been limited work on the use of chiral micellar media to catalyze Diels-. Alder reactions.

  8. A kinetic study of 1,3-dipolar cycloadditions in micellar media

    NARCIS (Netherlands)

    Rispens, T; Engberts, JBFN

    2003-01-01

    The kinetics of the 1,3-dipolar cycloadditions (DC) of benzonitrile oxide with a series of N-substituted maleimides in micellar media have been investigated. Surfactants studied include anionic sodium dodecyl sulfate, cationic cetyltrimethylammonium bromide, and a series of nonionic alkyl

  9. Interaction of antihypertensive drug amiloride with metal ions in micellar medium using fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Gujar, Varsha; Pundge, Vijaykumar; Ottoor, Divya

    2015-01-01

    Steady state and life time fluorescence spectroscopy have been employed to study the interaction of antihypertensive drug amiloride with biologically important metal ions i.e. Cu 2+ , Fe 2+ , Ni 2+ and Zn 2+ in various micellar media (anionic SDS (sodium dodecyl sulfate), nonionic TX-100 (triton X-100) and cationic CTAB (cetyl trimethyl ammonium bromide)). It was observed that fluorescence properties of drug remain unaltered in the absence of micellar media with increasing concentration of metal ions. However, addition of Cu 2+ , Fe 2+ and Ni 2+ caused fluorescence quenching of amiloride in the presence of anionic micelle, SDS. Binding of drug with metal ions at the charged micellar interface could be the possible reason for this pH-dependent metal-mediated fluorescence quenching. There were no remarkable changes observed due to metal ions addition when drug was present in cationic and nonionic micellar medium. The binding constant and bimolecular quenching constant were evaluated and compared for the drug–metal complexes using Stern–Volmer equation and fluorescence lifetime values. - Highlights: • Interaction of amiloride with biologically important metal ions, Fe 2+ , Cu 2+ , Ni 2+ and Zn 2+ . • Monitoring the interaction in various micelle at different pH by fluorescence spectroscopy. • Micelles acts as receptor, amiloride as transducer and metal ions as analyte in the present system. • Interaction study provides pH dependent quenching and binding mechanism of drug with metal ions

  10. Complexation of lysozyme with sodium caseinate and micellar casein in aqueous buffered solutions

    NARCIS (Netherlands)

    Antonov, Y.A.; Moldenaers, P.; Cardinaels, R.M.

    We present an extended structural and morphological study of the complexation of lysozyme (Lys) with sodium caseinate (SC) and micellar casein (MC) by means of turbidity measurements, phase analysis, dynamic, static and electrophoretic light scattering, bright-field and confocal laser scanning

  11. Atmospheric pressure photoionization for enhanced compatibility in on-line micellar electrokinetic chromatography-mass spectrometry

    NARCIS (Netherlands)

    Mol, Roelof; De Jong, Gerhardus J.; Somsen, Govert W.

    2005-01-01

    Atmospheric pressure photoionization (APPI) is presented as a novel means for the combination of micellar electrokinetic chromatography (MEKC) and mass spectrometry (MS). The on-line coupling is achieved using an adapted sheath flow interface installed on an orthogonal APPI source. Acetone or

  12. The Nature of the Micellar Stern Region As Studied by Reaction Kinetics. 2

    NARCIS (Netherlands)

    Buurma, Niklaas J.; Serena, Paola; Blandamer, Michael J.; Engberts, Jan B.F.N.

    2004-01-01

    The nature of rate-retarding effects of cationic micelles on the water-catalyzed hydrolyses of a series of para-substituted 1-benzoyl-1,2,4-triazoles (1a-f) and 1-benzoyl-3-phenyl-1,2,4-triazole (2) has been studied using kinetic methods. A comparison is drawn between medium effects in the micellar

  13. The Mobile Phase Motion in Ascending Micellar Thin-Layer Chromatography with Normal-Phase Plates

    NARCIS (Netherlands)

    Boichenko, Alexander P.; Makhno, Iryna V.; Renkevich, Anton Yu.; Loginova, Lidia P.

    2011-01-01

    The physical chemical characteristics (surface tension and viscosity) of micellar mobile phases based on the cationic surfactant cetylpiridinium chloride and additives of alcohols (ethanol, 1-propanol, 1-butanol, 1-pentanol) have been obtained in this work. The effect of mobile phase properties on

  14. Encapsulation and covalent binding of molecular payload in enzymatically activated micellar nanocarriers.

    Science.gov (United States)

    Rosenbaum, Ido; Harnoy, Assaf J; Tirosh, Einat; Buzhor, Marina; Segal, Merav; Frid, Liat; Shaharabani, Rona; Avinery, Ram; Beck, Roy; Amir, Roey J

    2015-02-18

    The high selectivity and often-observed overexpression of specific disease-associated enzymes make them extremely attractive for triggering the release of hydrophobic drug or probe molecules from stimuli-responsive micellar nanocarriers. Here we utilized highly modular amphiphilic polymeric hybrids, composed of a linear hydrophilic polyethylene glycol (PEG) and an esterase-responsive hydrophobic dendron, to prepare and study two diverse strategies for loading of enzyme-responsive micelles. In the first type of micelles, hydrophobic coumarin-derived dyes were encapsulated noncovalently inside the hydrophobic core of the micelle, which was composed of lipophilic enzyme-responsive dendrons. In the second type of micellar nanocarrier the hydrophobic molecular cargo was covalently linked to the end-groups of the dendron through enzyme-cleavable bonds. These amphiphilic hybrids self-assembled into micellar nanocarriers with their cargo covalently encapsulated within the hydrophobic core. Both types of micelles were highly responsive toward the activating enzyme and released their molecular cargo upon enzymatic stimulus. Importantly, while faster release was observed with noncovalent encapsulation, higher loading capacity and slower release rate were achieved with covalent encapsulation. Our results clearly indicate the great potential of enzyme-responsive micellar delivery platforms due to the ability to tune their payload capacities and release rates by adjusting the loading strategy.

  15. Stepwise dynamics of an anionic micellar film - Formation of crown lenses.

    Science.gov (United States)

    Lee, Jongju; Nikolov, Alex; Wasan, Darsh

    2017-06-15

    We studied the stepwise thinning of a microscopic circular foam film formed from an anionic micellar solution of sodium dodecyl sulfate (SDS). The foam film formed from the SDS micellar solution thins in a stepwise manner by the formation and expansion of a dark spot(s) of one layer less than the film thickness. During the last stages of film thinning (e.g., a film with one micellar layer), the dark spot expansion occurs via two steps. Initially, a small dark circular spot inside a film of several microns in size is formed, which expands at a constant rate. Then, a ridge along the expanding spot is formed. As the ridge grows, it becomes unstable and breaks into regular crown lenses, which are seen as white spots in the reflected light at the border of the dark spot with the surrounding thicker film. The Rayleigh type of instability contributes to the formation of the lenses, which results in the increase of the dark spot expansion rate with time. We applied the two-dimensional micellar-vacancy diffusion model and took into consideration the effects of the micellar layering and film volume on the rate of the dark spot expansion [Lee et al., 2016] to predict the rate of the dark spot expansion for a 0.06M SDS film in the presence of lenses. We briefly discuss the Rayleigh type of instability in the case of a 0.06M SDS foam film. The goals of this study are to reveal why the crown lenses are formed during the foam film stratification and to elucidate their effect on the rate of spot expansion. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Multicompartment micellar aggregates of linear ABC amphiphiles in solvents selective for the C block: A Monte Carlo simulation

    KAUST Repository

    Zhu, Yutian; Yu, Haizhou; Wang, Yongmei; Cui, Jie; Kong, Weixin; Jiang, Wei

    2012-01-01

    the simulations and the detailed phase diagrams for the ABC amphiphiles with different block lengths are obtained. The simulation results reveal that the micellar structure is largely controlled by block length, solvent quality, and incompatibility between

  17. Analysis of micellar and vesicular lecithin and cholesterol in model bile using 1H- and 31P-NMR

    NARCIS (Netherlands)

    de Graaf, M. P.; Groen, A. K.; Bovée, W. M.

    1995-01-01

    The distribution of phospholipid and cholesterol between the vesicular and micellar phases in bile plays an important role in the formation of cholesterol gallstones. Conventional analytical procedures to determine the distribution are potentially unreliable because they disturb the distribution of

  18. Covalent and non-covalent curcumin loading in acid-responsive polymeric micellar nanocarriers

    Science.gov (United States)

    Gao, Min; Chen, Chao; Fan, Aiping; Zhang, Ju; Kong, Deling; Wang, Zheng; Zhao, Yanjun

    2015-07-01

    Poor aqueous solubility, potential degradation, rapid metabolism and elimination lead to low bioavailability of pleiotropic impotent curcumin. Herein, we report two types of acid-responsive polymeric micelles where curcumin was encapsulated via both covalent and non-covalent modes for enhanced loading capacity and on-demand release. Biodegradable methoxy poly(ethylene glycol)-poly(lactic acid) copolymer (mPEG-PLA) was conjugated with curcumin via a hydrazone linker, generating two conjugates differing in architecture (single-tail versus double-tail) and free curcumin was encapsulated therein. The two micelles exhibited similar hydrodynamic size at 95 ± 3 nm (single-tail) and 96 ± 3 nm (double-tail), but their loading capacities differed significantly at 15.0 ± 0.5% (w/w) (single-tail) and 4.8 ± 0.5% (w/w) (double-tail). Under acidic sink conditions (pH 5.0 and 6.0), curcumin displayed a faster release from the single-tail nanocarrier, which was correlated to a low IC50 of 14.7 ± 1.6 (μg mL-1) compared to the value of double-tail micelle (24.9 ± 1.3 μg mL-1) in HeLa cells. The confocal imaging and flow cytometry analysis demonstrated a superior capability of single-tail micelle for intracellular curcumin delivery, which was a consequence of the higher loading capacity and lower degree of mPEG surface coverage. In conclusion, the dual loading mode is an effective means to increase the drug content in the micellar nanocarriers whose delivery efficiency is highly dependent on its polymer-drug conjugate architecture. This strategy offers an alternative nanoplatform for intracellularly delivering impotent hydrophobic agents (i.e. curcumin) in an efficient stimuli-triggered way, which is valuable for the enhancement of curcumin’s efficacy in managing a diverse range of disorders.

  19. Covalent and non-covalent curcumin loading in acid-responsive polymeric micellar nanocarriers

    International Nuclear Information System (INIS)

    Gao, Min; Chen, Chao; Fan, Aiping; Wang, Zheng; Zhao, Yanjun; Zhang, Ju; Kong, Deling

    2015-01-01

    Poor aqueous solubility, potential degradation, rapid metabolism and elimination lead to low bioavailability of pleiotropic impotent curcumin. Herein, we report two types of acid-responsive polymeric micelles where curcumin was encapsulated via both covalent and non-covalent modes for enhanced loading capacity and on-demand release. Biodegradable methoxy poly(ethylene glycol)-poly(lactic acid) copolymer (mPEG-PLA) was conjugated with curcumin via a hydrazone linker, generating two conjugates differing in architecture (single-tail versus double-tail) and free curcumin was encapsulated therein. The two micelles exhibited similar hydrodynamic size at 95 ± 3 nm (single-tail) and 96 ± 3 nm (double-tail), but their loading capacities differed significantly at 15.0 ± 0.5% (w/w) (single-tail) and 4.8 ± 0.5% (w/w) (double-tail). Under acidic sink conditions (pH 5.0 and 6.0), curcumin displayed a faster release from the single-tail nanocarrier, which was correlated to a low IC_5_0 of 14.7 ± 1.6 (μg mL"−"1) compared to the value of double-tail micelle (24.9 ± 1.3 μg mL"−"1) in HeLa cells. The confocal imaging and flow cytometry analysis demonstrated a superior capability of single-tail micelle for intracellular curcumin delivery, which was a consequence of the higher loading capacity and lower degree of mPEG surface coverage. In conclusion, the dual loading mode is an effective means to increase the drug content in the micellar nanocarriers whose delivery efficiency is highly dependent on its polymer–drug conjugate architecture. This strategy offers an alternative nanoplatform for intracellularly delivering impotent hydrophobic agents (i.e. curcumin) in an efficient stimuli-triggered way, which is valuable for the enhancement of curcumin’s efficacy in managing a diverse range of disorders. (paper)

  20. Recent Progress in Functional Micellar Carriers with Intrinsic Therapeutic Activities for Anticancer Drug Delivery.

    Science.gov (United States)

    Qu, Ying; Chu, BingYang; Shi, Kun; Peng, JinRong; Qian, ZhiYong

    2017-12-01

    Polymeric micelles have presented superior delivery properties for poorly water-soluble chemotherapeutic agents. However, it remains discouraging that there may be some additional short or long-term toxicities caused by the metabolites of high quantities of carriers. If carriers had simultaneous therapeutic effects with the drug, these issues would not be a concern. For this, carriers not only simply act as drug carriers, but also exert an intrinsic therapeutic effect as a therapeutic agent. The functional micellar carriers would be beneficial to maximize the anticancer effect, overcome the drug resistance and reduce the systemic toxicity. In this review, we aim to summarize the recent progress on the development of functional micellar carriers with intrinsic anticancer activities for the delivery of anticancer drugs. This review focuses on the design strategies, properties of carriers and the drug loading behavior. In addition, the combinational therapeutic effects between carriers and chemotherapeutic agents are also discussed.

  1. Responsive micellar films of amphiphilic block copolymer micelles: control on micelle opening and closing.

    Science.gov (United States)

    Chen, Zhiquan; He, Changcheng; Li, Fengbin; Tong, Ling; Liao, Xingzhi; Wang, Yong

    2010-06-01

    We reported the deliberate control on the micelle opening and closing of amphiphilic polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) micellar films by exposing them to selective solvents. We first treated the micellar films with polar solvents including ethanol and water (pH = 4, 8, and 12) that have different affinities to P2VP. We observed opening of the micelles in all the cases. Both the size of opened pores and the opening rate are dependent on the solvency of different solvents for P2VP. We then explored the closing behavior of the opened micelles using solvents having different affinities to PS. We found that the opened micelles were recovered to their initial closed micelle forms. The recovery was accompanied by a slow micelle disassociation process which gradually reduced the micelle size. The rates of the micelle closing and disassociation are also dependent on the solvency of different solvents for PS.

  2. Use of micellar casein concentrate for Greek-style yogurt manufacturing: effects on processing and product properties.

    Science.gov (United States)

    Bong, D D; Moraru, C I

    2014-03-01

    The objective of this work was to develop and optimize an alternative make process for Greek-style yogurt (GSY), in which the desired level of protein was reached by fortification with micellar casein concentrate (MCC) obtained from milk by microfiltration. Two MCC preparations with 58 and 88% total protein (MCC-58 and MCC-88) were used to fortify yogurt milk to 9.80% (wt/wt) protein. Strained GSY of similar protein content was used as the control. Yogurt milk bases were inoculated with 0.02% (wt/wt) or 0.04% (wt/wt) direct vat set starter culture and fermented until pH 4.5. The acidification rate was faster for the MCC-fortified GSY than for the control, regardless of the inoculation level, which was attributed to the higher nonprotein nitrogen content in the MCC-fortified milk. Steady shear rate rheological analysis indicated a shear-thinning behavior for all GSY samples, which fitted well with the power law model. Dynamic rheological analysis at 5°C showed a weak frequency dependency of the elastic modulus (G') and viscous modulus (G") for all GSY samples, with G' > G", indicating a weak gel structure. Differences in the magnitude of viscoelastic parameters between the 2 types of GSY were found, with G' of MCC-fortified GSY yogurt. Differences were also noticed in water-holding capacity, which was lower for the MCC-fortified GSY compared with the control, attributed to lower serum protein content in the former. Despite some differences in the physicochemical characteristics of the final product compared with GSY manufactured by straining, the alternative process developed here is a feasible alternative to the traditional GSY make process, with environmental and possibly financial benefits to the dairy industry. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  3. Transepithelial Transport of Curcumin in Caco-2 Cells Is significantly Enhanced by Micellar Solubilisation.

    Science.gov (United States)

    Frank, Jan; Schiborr, Christina; Kocher, Alexa; Meins, Jürgen; Behnam, Dariush; Schubert-Zsilavecz, Manfred; Abdel-Tawab, Mona

    2017-03-01

    Curcumin, the active constituent of Curcuma longa L. (family Zingiberaceae), has gained increasing interest because of its anti-cancer, anti-inflammatory, anti-diabetic, and anti-rheumatic properties associated with good tolerability and safety up to very high doses of 12 g. Nanoscaled micellar formulations on the base of Tween 80 represent a promising strategy to overcome its low oral bioavailability. We therefore aimed to investigate the uptake and transepithelial transport of native curcumin (CUR) vs. a nanoscaled micellar formulation (Sol-CUR) in a Caco-2 cell model. Sol-CUR afforded a higher flux than CUR (39.23 vs. 4.98 μg min -1  cm -2 , respectively). This resulted in a higher P app value of 2.11 × 10 -6  cm/s for Sol-CUR compared to a P app value of 0.56 × 10 -6  cm/s for CUR. Accordingly a nearly 9.5 fold higher amount of curcumin was detected on the basolateral side at the end of the transport experiments after 180 min with Sol-CUR compared to CUR. The determined 3.8-fold improvement in the permeability of curcumin is in agreement with an up to 185-fold increase in the AUC of curcumin observed in humans following the oral administration of the nanoscaled micellar formulation compared to native curcumin. The present study demonstrates that the enhanced oral bioavailability of micellar curcumin formulations is likely a result of enhanced absorption into and increased transport through small intestinal epithelial cells.

  4. One electron reduction and absorption characteristics of Cresyl violet in micellar medium

    International Nuclear Information System (INIS)

    Gawandi, Vijay B.; Guha, S.N.; Hari Mohan

    2000-01-01

    Effect of surfactant micelles on absorption characteristics of Cresyl violet (CV) and on its redox reactions have been studied. Among the various surfactants investigated anionic surfactants particularly sodium lauryl sulfate (SLS) and sodium dodecyl benzene sulfonate (SDDBS) showed marked effect on these properties. Reactions of hydrated electron in these micellar media were studied using the technique of nanosecond pulse radiolysis. Results of other surfactants, viz.BSS, CTAB and TritonX-100 have also been presented. (author)

  5. Fluorescence spectroscopic studies on substituted porphyrins in homogeneous solvents and cationic micellar medium

    International Nuclear Information System (INIS)

    Phukan, Smritakshi; Mishra, Bhupendra; Chandra Shekar, K.P.; Kumar, Anil; Kumar, Dalip; Mitra, Sivaprasad

    2013-01-01

    Steady state and time-resolved fluorescence properties of porphyrin appended 1,3,4-oxadiazoles and thiazoles were described in homogeneous medium as well as in presence of cationic surfactant cetyltrimethylammonium bromide (CTAB). The electron withdrawing substituent on the porphyrin moiety in both the cases make a donor–spacer–acceptor type of intramolecular photoinduced electron transfer (PET) system resulting substantial quenching in porphyrin fluorescence due to partial energy migration towards the acceptor in the excited state. The increase in fluorescence yield as well as appreciable difference in fluorescence decay behavior in aqueous buffer solution of pH 4.2 from that in chloroform solution is believed due to partial protonation of the porphyrin ring. All the investigated systems show preferential binding into the interfacial region of the micellar sub-domain with varying degree of penetration depending on the nature of the substituent. Almost 2–4 fold increase in fluorescence yield for the probes is explained on the basis of restricted flexibility and corresponding decrease in total nonradiative rate inside the micellar interface layer. - Highlights: ► Synthesis and detail fluorescence studies of a series of porphyrin appended 1,3,4-oxadiazoles and thiazoles. ► Comparison of homogeneous solvent study with that in CTAB. ► Substantial porphyrin fluorescence quenching in donor–spacer–acceptor type system. ► Preferential binding of the substituted porphyrins in micellar sub-domain. ► Appreciable increase in fluorescence yield in micellar interface layer is due to decrease in total nonradiative rate.

  6. Photochemical assessment of UO2+2 complexation in Triton X-100 micellar system

    International Nuclear Information System (INIS)

    Das, S.K.; Ganguly, B.N.

    1994-01-01

    This is a report on the spectral characteristics of UO 2 +2 in the excited state in the Triton X-100 micellar medium. The downward curving of the Stern-Volmer plot explains the two kinds of populations of UO 2 +2 upon micellization. A blue shift of the quenched emission is ascribed due to the collisional encounter of UO 2 +2 with the head groups of Triton X-100. (author). 5 refs., 2 figs

  7. Deracemization of bilirubin as the marker of the chirality of micellar aggregates.

    Science.gov (United States)

    Sorrenti, Alessandro; Altieri, Barbara; Ceccacci, Francesca; Di Profio, Pietro; Germani, Raimondo; Giansanti, Luisa; Savelli, Gianfranco; Mancini, Giovanna

    2012-01-01

    The deracemization of bilirubin in micellar aggregates of structurally correlated chiral surfactants was studied by circular dichroism experiments and exploited as the marker of the expression of chirality of the aggregates. The obtained results suggest that the hydrophobic interactions control the transfer of chirality from the monomers to the aggregates, and that different regions of the same aggregate might feature opposite enantiorecognition capabilities. Copyright © 2011 Wiley-Liss, Inc.

  8. Fundamental Characterization of the Micellar Self-Assembly of Sophorolipid Esters.

    Science.gov (United States)

    Koh, Amanda; Todd, Katherine; Sherbourne, Ezekiel; Gross, Richard A

    2017-06-13

    Surfactants are ubiquitous constituents of commercial and biological systems that function based on complex structure-dependent interactions. Sophorolipid (SL) n-alkyl esters (SL-esters) comprise a group of modified naturally derived glycolipids from Candida bombicola. Herein, micellar self-assembly behavior as a function of SL-ester chain length was studied. Surface tensions as low as 31.2 mN/m and critical micelle concentrations (CMCs) as low as 1.1 μM were attained for diacetylated SL-decyl ester (dASL-DE) and SL-octyl ester, respectively. For deacetylated SL-esters, CMC values reach a lower limit at SL-ester chains above n-butyl (SL-BE, 1-3 μM). This behavior of SL-esters with increasing hydrophobic tail length is unlike other known surfactants. Diffusion-ordered spectroscopy (DOSY) and T 1 relaxation NMR experiments indicate this behavior is due to a change in intramolecular interactions, which impedes the self-assembly of SL-esters with chain lengths above SL-BE. This hypothesis is supported by micellar thermodynamics where a disruption in trends occurs at n-alkyl ester chain lengths above those of SL-BE and SL-hexyl ester (SL-HE). Diacetylated (dA) SL-esters exhibit an even more unusual trend in that CMC increases from 1.75 to 815 μM for SL-ester chain lengths of dASL-BE and dASL-DE, respectively. Foaming studies, performed to reveal the macroscopic implications of SL-ester micellar behavior, show that the observed instability in foams formed using SL-esters are due to coalescence, which highlights the importance of understanding intermicellar interactions. This work reveals that SL-esters are an important new family of green high-performing surfactants with unique structure-property relationships that can be tuned to optimize micellar characteristics.

  9. Interaction of antihypertensive drug amiloride with metal ions in micellar medium using fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gujar, Varsha; Pundge, Vijaykumar; Ottoor, Divya, E-mail: divya@chem.unipune.ac.in

    2015-05-15

    Steady state and life time fluorescence spectroscopy have been employed to study the interaction of antihypertensive drug amiloride with biologically important metal ions i.e. Cu{sup 2+}, Fe{sup 2+}, Ni{sup 2+} and Zn{sup 2+} in various micellar media (anionic SDS (sodium dodecyl sulfate), nonionic TX-100 (triton X-100) and cationic CTAB (cetyl trimethyl ammonium bromide)). It was observed that fluorescence properties of drug remain unaltered in the absence of micellar media with increasing concentration of metal ions. However, addition of Cu{sup 2+}, Fe{sup 2+} and Ni{sup 2+} caused fluorescence quenching of amiloride in the presence of anionic micelle, SDS. Binding of drug with metal ions at the charged micellar interface could be the possible reason for this pH-dependent metal-mediated fluorescence quenching. There were no remarkable changes observed due to metal ions addition when drug was present in cationic and nonionic micellar medium. The binding constant and bimolecular quenching constant were evaluated and compared for the drug–metal complexes using Stern–Volmer equation and fluorescence lifetime values. - Highlights: • Interaction of amiloride with biologically important metal ions, Fe{sup 2+}, Cu{sup 2+}, Ni{sup 2+} and Zn{sup 2+}. • Monitoring the interaction in various micelle at different pH by fluorescence spectroscopy. • Micelles acts as receptor, amiloride as transducer and metal ions as analyte in the present system. • Interaction study provides pH dependent quenching and binding mechanism of drug with metal ions.

  10. Ultrafast relaxation dynamics of a biologically relevant probe dansyl at the micellar surface.

    Science.gov (United States)

    Sarkar, Rupa; Ghosh, Manoranjan; Pal, Samir Kumar

    2005-02-01

    We report picosecond-resolved measurement of the fluorescence of a well-known biologically relevant probe, dansyl chromophore at the surface of a cationic micelle (cetyltrimethylammonium bromide, CTAB). The dansyl chromophore has environmentally sensitive fluorescence quantum yields and emission maxima, along with large Stokes shift. In order to study the solvation dynamics of the micellar environment, we measured the fluorescence of dansyl chromophore attached to the micellar surface. The fluorescence transients were observed to decay (with time constant approximately 350 ps) in the blue end and rise with similar timescale in the red end, indicative of solvation dynamics of the environment. The solvation correlation function is measured to decay with time constant 338 ps, which is much slower than that of ordinary bulk water. Time-resolved anisotropy of the dansyl chromophore shows a bi-exponential decay with time constants 413 ps (23%) and 1.3 ns (77%), which is considerably slower than that in free solvents revealing the rigidity of the dansyl-micelle complex. Time-resolved area-normalized emission spectroscopic (TRANES) analysis of the time dependent emission spectra of the dansyl chromophore in the micellar environment shows an isoemissive point at 21066 cm-1. This indicates the fluorescence of the chromophore contains emission from two kinds of excited states namely locally excited state (prior to charge transfer) and charge transfer state. The nature of the solvation dynamics in the micellar environments is therefore explored from the time-resolved anisotropy measurement coupled with the TRANES analysis of the fluorescence transients. The time scale of the solvation is important for the mechanism of molecular recognition.

  11. Self-association of analgesics in aqueous solution: micellar properties of dextropropoxyphene hydrochloride and methadone hydrochloride.

    Science.gov (United States)

    Attwood, D; Tolley, J A

    1980-08-01

    The solution properties of several analgesics including dextropropoxyphene hydrochloride, methadone hydrochloride, dextromoramide acid tartrate and dipipanone hydrochloride have been examined using light scattering, conductivity, vapour pressure osmometry and surface tension techniques. A micellar pattern of association was established for dextropropoxyphene hydrochloride and methadone hydrochloride and critical micelle concentrations and aggregation numbers are reported. The hydrophobic contribution to the free energy of micellization of dextropropoxyphene was determined from measurement of the critical micelle concentration in the presence of added electrolyte.

  12. Probing the amphiphile micellar to hexagonal phase transition using Positron Annihilation Lifetime Spectroscopy.

    Science.gov (United States)

    Dong, Aurelia W; Fong, Celesta; Hill, Anita J; Boyd, Ben J; Drummond, Calum J

    2013-07-15

    Positron Annihilation Lifetime Spectroscopy (PALS) has been utilised only sparingly for structural characterisation in self assembled materials. Inconsistencies in approaches to experimental configuration and data analysis between studies has complicated comparisons between studies, meaning that the technique has not provided a cohesive data set across the study of different self assembled systems that advance the technique towards an important tool in soft matter research. In the current work a systematic study was conducted using ionic and non-ionic micellar systems with increasing surfactant concentration to probe positron behaviour on changes between micellar phase structures, and data analysed using contemporary approaches to fit four component spectra. A characteristic orthopositronium lifetime (in the organic regions) of 3.5±0.2 ns was obtained for the hexagonal phase for surfactants with C12 alkyl chains. Chemical quenching of the positron species was also observed for systems with ionic amphiphiles. The application of PALS has also highlighted an inconsistency in the published phase diagram for the octa(ethylene oxide) monododecyl ether (C12EO8) system. These results provide new insight into how the physical properties of micellar systems can be related to PALS parameters and means that the PALS technique can be applied to other more complex self-assembled amphiphile systems. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Mixtures of lecithin and bile salt can form highly viscous wormlike micellar solutions in water.

    Science.gov (United States)

    Cheng, Chih-Yang; Oh, Hyuntaek; Wang, Ting-Yu; Raghavan, Srinivasa R; Tung, Shih-Huang

    2014-09-02

    The self-assembly of biological surfactants in water is an important topic for study because of its relevance to physiological processes. Two common types of biosurfactants are lecithin (phosphatidylcholine) and bile salts, which are both present in bile and involved in digestion. Previous studies on lecithin-bile salt mixtures have reported the formation of short, rodlike micelles. Here, we show that lecithin-bile salt micelles can be further induced to grow into long, flexible wormlike structures. The formation of long worms and their resultant entanglement into transient networks is reflected in the rheology: the fluids become viscoelastic and exhibit Maxwellian behavior, and their zero-shear viscosity can be up to a 1000-fold higher than that of water. The presence of worms is further confirmed by data from small-angle neutron and X-ray scattering and from cryo-transmission electron microscopy (cryo-TEM). We find that micellar growth peaks at a specific molar ratio (near equimolar) of bile salt:lecithin, which suggests a strong binding interaction between the two species. In addition, micellar growth also requires a sufficient concentration of background electrolyte such as NaCl or sodium citrate that serves to screen the electrostatic repulsion of the amphiphiles and to "salt out" the amphiphiles. We postulate a mechanism based on changes in the molecular geometry caused by bile salts and electrolytes to explain the micellar growth.

  14. Hydrophobically modified inulin as an amphiphilic carbohydrate polymer for micellar delivery of paclitaxel for intravenous route.

    Science.gov (United States)

    Muley, Pratik; Kumar, Sunny; El Kourati, Fadoua; Kesharwani, Siddharth S; Tummala, Hemachand

    2016-03-16

    Micellization offers several advantages for the delivery of water insoluble drugs including a nanoparticulate 'core-shell' delivery system for drug targeting. Recently, hydrophobically modified polysaccharides (HMPs) are gaining recognition as micelle forming polymers to encapsulate hydrophobic drugs. In this manuscript, for the first time, we have evaluated the self-assembling properties of a lauryl carbamate derivative of the poly-fructose natural polymer inulin (Inutec SP1(®) (INT)) to form paclitaxel (PTX) loaded micelles. INT self-assembled into well-defined micellar structures in aqueous environment with a low critical micellar concentration of 27.8 μg/ml. INT micelles exhibited excellent hemocompatibility and low toxicity to cultured cells. PTX loaded INT micelles exhibited a mean size of 256.37 ± 10.45 nm with excellent drug encapsulation efficiency (95.66 ± 2.25%) and loading (8.69 ± 0.22%). PTX loaded micelles also displayed sustained release of PTX and enhanced anti-cancer efficacy in-vitro in mouse melanoma cells (B16F10) compared to Taxol formulation with Cremophor EL as solvent. In addition, PTX loaded INT micelles exhibited comparable in-vivo antitumor activity in B16F10 allograft mouse model at half the dose of Taxol. In conclusion, INT offers safe, inexpensive and natural alternative to widely used PEG-modified polymers for the formulation of micellar delivery systems for paclitaxel. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Can neutral analytes be concentrated by transient isotachophoresis in micellar electrokinetic chromatography and how much?

    Science.gov (United States)

    Matczuk, Magdalena; Foteeva, Lidia S; Jarosz, Maciej; Galanski, Markus; Keppler, Bernhard K; Hirokawa, Takeshi; Timerbaev, Andrei R

    2014-06-06

    Transient isotachophoresis (tITP) is a versatile sample preconcentration technique that uses ITP to focus electrically charged analytes at the initial stage of CE analysis. However, according to the ruling principle of tITP, uncharged analytes are beyond its capacity while being separated and detected by micellar electrokinetic chromatography (MEKC). On the other hand, when these are charged micelles that undergo the tITP focusing, one can anticipate the concentration effect, resulting from the formation of transient micellar stack at moving sample/background electrolyte (BGE) boundary, which increasingly accumulates the analytes. This work expands the enrichment potential of tITP for MEKC by demonstrating the quantitative analysis of uncharged metal-based drugs from highly saline samples and introducing to the BGE solution anionic surfactants and buffer (terminating) co-ions of different mobility and concentration to optimize performance. Metallodrugs of assorted lipophilicity were chosen so as to explore whether their varying affinity toward micelles plays the role. In addition to altering the sample and BGE composition, optimization of the detection capability was achieved due to fine-tuning operational variables such as sample volume, separation voltage and pressure, etc. The results of optimization trials shed light on the mechanism of micellar tITP and render effective determination of selected drugs in human urine, with practical limits of detection using conventional UV detector. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Microstructural evolution of a model, shear-banding micellar solution during shear startup and cessation.

    Science.gov (United States)

    López-Barrón, Carlos R; Gurnon, A Kate; Eberle, Aaron P R; Porcar, Lionel; Wagner, Norman J

    2014-04-01

    We present direct measurements of the evolution of the segmental-level microstructure of a stable shear-banding polymerlike micelle solution during flow startup and cessation in the plane of flow. These measurements provide a definitive, quantitative microstructural understanding of the stages observed during flow startup: an initial elastic response with limited alignment that yields with a large stress overshoot to a homogeneous flow with associated micellar alignment that persists for approximately three relaxation times. This transient is followed by a shear (kink) band formation with a flow-aligned low-viscosity band that exhibits shear-induced concentration fluctuations and coexists with a nearly isotropic band of homogenous, highly viscoelastic micellar solution. Stable, steady banding flow is achieved only after approximately two reptation times. Flow cessation from this shear-banded state is also found to be nontrivial, exhibiting an initial fast relaxation with only minor structural relaxation, followed by a slower relaxation of the aligned micellar fluid with the equilibrium fluid's characteristic relaxation time. These measurements resolve a controversy in the literature surrounding the mechanism of shear banding in entangled wormlike micelles and, by means of comparison to existing literature, provide further insights into the mechanisms driving shear-banding instabilities in related systems. The methods and instrumentation described should find broad use in exploring complex fluid rheology and testing microstructure-based constitutive equations.

  17. Lateral Order and Self-Organized Morphology of Diblock Copolymer Micellar Films

    Directory of Open Access Journals (Sweden)

    Jiun-You Liou

    2018-05-01

    Full Text Available We report the lateral order and self-organized morphology of diblock copolymer polystyrene-block-poly(2-vinylpyridine, P(S-b-2VP, and micelles on silicon substrates (SiOx/Si. These micellar films were prepared by spin coating from polymer solutions of varied concentration of polymer in toluene onto SiOx/Si, and were investigated with grazing-incidence small-angle X-ray scattering (GISAXS and an atomic force microscope (AFM. With progressively increased surface coverage with increasing concentration, loosely packed spherical micelles, ribbon-like nanostructures, and a second layer of spherical micelles were obtained sequentially. Quantitative analysis and simulations of the micellar packing demonstrates that the spatial ordering of the loosely packed spherical micelles altered from short-range order to hexagonal order when the micellar coverage increased from small to moderate densities of the covered surface. At large densities, anisotropic fusion between spherical micelles caused the ribbon-like nanostructures to have a short-range spatial order; the ordering quality of the second layer was governed by the rugged surface of the underlying layer because the valleys between the ribbon-like nanostructures allowed for further deposition of spherical micelles.

  18. Retention of bile salts in micellar electrokinetic chromatography: relation of capacity factor to octanol-water partition coefficient and critical micellar concentration.

    Science.gov (United States)

    Lucangioli, S E; Carducci, C N; Tripodi, V P; Kenndler, E

    2001-12-25

    The capacity factors of 16 anionic cholates (from six bile salts, including their glyco- and tauro-conjugates) were determined in a micellar electrokinetic chromatography (MEKC) system consisting of buffer, pH 7.5 (phosphate-boric acid; 20 mmol/l) with 50 mmol/l sodium dodecyl sulfate (SDS) as micelle former and 10% acetonitrile as organic modifier. The capacity factors of the fully dissociated, negatively charged analytes (ranging between 0.2 and 60) were calculated from their mobilities, with a reference background electrolyte (BGE) without SDS representing "free" solution. For comparison, the capacity factors were derived for a second reference BGE where the SDS concentration (5 mmol/l) is close to the critical micellar concentration (CMC). The capacity factors are compared with the logarithm of the octanol-water partition coefficient, log Pow, as measure for lipophilicity. Clear disagreement between these two parameters is found especially for epimeric cholates with the hydroxy group in position 7. In contrast, fair relation between the capacity factor of the analytes and their CMC is observed both depending strongly on the orientation of the OH groups, and tauro-conjugation as well. In this respect the retention behaviour of the bile salts in MEKC seems to reflect their role as detergents in living systems, and might serve as model parameter beyond lipophilicity.

  19. Multiscale Modeling of the Effects of Salt and Perfume Raw Materials on the Rheological Properties of Commercial Threadlike Micellar Solutions.

    Science.gov (United States)

    Tang, Xueming; Zou, Weizhong; Koenig, Peter H; McConaughy, Shawn D; Weaver, Mike R; Eike, David M; Schmidt, Michael J; Larson, Ronald G

    2017-03-23

    We link micellar structures to their rheological properties for two surfactant body-wash formulations at various concentrations of salts and perfume raw materials (PRMs) using molecular simulations and micellar-scale modeling, as well as traditional surfactant packing arguments. The two body washes, namely, BW-1EO and BW-3EO, are composed of sodium lauryl ethylene glycol ether sulfate (SLEnS, where n is the average number of ethylene glycol repeat units), cocamidopropyl betaine (CAPB), ACCORD (which is a mixture of six PRMs), and NaCl salt. BW-3EO is an SLE3S-based body wash, whereas BW-1EO is an SLE1S-based body wash. Additional PRMs are also added into the body washes. The effects of temperature, salt, and added PRMs on micellar lengths, breakage times, end-cap free energies, and other properties are obtained from fits of the rheological data to predictions of the "Pointer Algorithm" [ Zou , W. ; Larson , R.G. J. Rheol. 2014 , 58 , 1 - 41 ], which is a simulation method based on the Cates model of micellar dynamics. Changes in these micellar properties are interpreted using the Israelachvili surfactant packing argument. From coarse-grained molecular simulations, we infer how salt modifies the micellar properties by changing the packing between the surfactant head groups, with the micellar radius remaining nearly constant. PRMs do so by partitioning to different locations within the micelles according to their octanol/water partition coefficient P OW and chemical structures, adjusting the packing of the head and/or tail groups, and by changing the micelle radius, in the case of a large hydrophobic PRM. We find that relatively hydrophilic PRMs with log P OW 4, are isolated deep inside the micelle, separating from the tails and swelling the radius of the micelle, leading to shorter micelles and much lower viscosities, leading eventually to swollen-droplet micelles.

  20. First Example of a Lipophilic Porphyrin-Cardanol Hybrid Embedded in a Cardanol-Based Micellar Nanodispersion

    Directory of Open Access Journals (Sweden)

    Giuseppe Vasapollo

    2012-10-01

    Full Text Available Cardanol is a natural and renewable organic raw material obtained as the major chemical component by vacuum distillation of cashew nut shell liquid. In this work a new sustainable procedure for producing cardanol-based micellar nanodispersions having an embedded lipophilic porphyrin itself peripherally functionalized with cardanol substituents (porphyrin-cardanol hybrid has been described for the first time. In particular, cardanol acts as the solvent of the cardanol hybrid porphyrin and cholesterol as well as being the main component of the nanodispersions. In this way a “green” micellar nanodispersion, in which a high percentage of the micellar system is derived from renewable “functional” molecules, has been produced.

  1. Evolution of ZnS Nanoparticles via Facile CTAB Aqueous Micellar Solution Route: A Study on Controlling Parameters

    Directory of Open Access Journals (Sweden)

    Gradzielski Michael

    2008-01-01

    Full Text Available Abstract Synthesis of semiconductor nanoparticles with new photophysical properties is an area of special interest. Here, we report synthesis of ZnS nanoparticles in aqueous micellar solution of Cetyltrimethylammonium bromide (CTAB. The size of ZnS nanodispersions in aqueous micellar solution has been calculated using UV-vis spectroscopy, XRD, SAXS, and TEM measurements. The nanoparticles are found to be polydispersed in the size range 6–15 nm. Surface passivation by surfactant molecules has been studied using FTIR and fluorescence spectroscopy. The nanoparticles have been better stabilized using CTAB concentration above 1 mM. Furthermore, room temperature absorption and fluorescence emission of powdered ZnS nanoparticles after redispersion in water have also been investigated and compared with that in aqueous micellar solution. Time-dependent absorption behavior reveals that the formation of ZnS nanoparticles depends on CTAB concentration and was complete within 25 min.

  2. Complementary experimental-simulational study of surfactant micellar phase in the extraction process of metallic ions: Effects of temperature and salt concentration

    Science.gov (United States)

    Soto-Ángeles, Alan Gustavo; Rodríguez-Hidalgo, María del Rosario; Soto-Figueroa, César; Vicente, Luis

    2018-02-01

    The thermoresponsive micellar phase behaviour that exhibits the Triton-X-100 micelles by temperature effect and addition of salt in the extraction process of metallic ions was explored from mesoscopic and experimental points. In the theoretical study, we analyse the formation of Triton-X-100 micelles, load and stabilization of dithizone molecules and metallic ions extraction inside the micellar core at room temperature; finally, a thermal analysis is presented. In the experimental study, the spectrophotometric outcomes confirm the solubility of the copper-dithizone complex in the micellar core, as well as the extraction of metallic ions of aqueous environment via a cloud-point at 332.2 K. The micellar solutions with salt present a low absorbance value compared with the micellar solutions without salt. The decrease in the absorbance value is attributed to a change in the size of hydrophobic region of colloidal micelles. All transitory stages of extraction process are discussed and analysed in this document.

  3. Removal of phenol from synthetic waste water using Gemini micellar-enhanced ultrafiltration (GMEUF)

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wenxiang [MOE Key Laboratory of Regional Energy and Environmental Systems Optimization, Resources and Environmental Research Academy, North China Electric Power University, Beijing 102206 (China); Huang, Guohe, E-mail: huang@iseis.org [MOE Key Laboratory of Regional Energy and Environmental Systems Optimization, Resources and Environmental Research Academy, North China Electric Power University, Beijing 102206 (China); Wei, Jia [Faculty of Engineering and Applied Science, University of Regina, Regina, Saskatchewan, Canada S4S 0A2 (Canada); Li, Huiqin; Zheng, Rubing; Zhou, Ya [MOE Key Laboratory of Regional Energy and Environmental Systems Optimization, Resources and Environmental Research Academy, North China Electric Power University, Beijing 102206 (China)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer Gemini surfactant micellar enhanced ultrafiltration was used to remove phenol. Black-Right-Pointing-Pointer The effect of different hydrophilic head groups of surfactant was analyzed. Black-Right-Pointing-Pointer SEM, ATR-FTIR and mercury porosimeter were applied to elucidate membrane fouling. Black-Right-Pointing-Pointer Gemini surfactant had superior performance in comparing with conventional surfactant. - Abstract: Comprehensive studies were conducted on the phenol wastewater ultrafiltration (UF) with the help of various concentrations of cationic Gemini surfactant (N1-dodecyl-N1,N1,N2,N2-tetramethyl-N2-octylethane-1,2-diaminium bromide, CG), conventional cationic surfactant (dodecyl trimethyl ammonium bromide, DTAB), anionic surfactant (sodium dodecyl sulfate, SDS) and nonionic surfactant ((dodecyloxy)polyethoxyethanol, Brij35). A flat sheet module with polyethersulfone (PES) membrane was employed in this investigation. The effects of feed concentration (phenol and surfactant) on the retention of phenol and surfactant, permeate flux and membrane fouling by micelles were evaluated. The distribution coefficient (D), the loading of the micelles (L{sub m}) and the equilibrium distribution constant (K) were also utilized to estimate the micellar-enhanced ultrafiltration ability for phenol. Scanning electron microscope (SEM), Fourier transform infrared spectrometer with attenuated total reflectance accessory (ATR-FTIR) and mercury porosimeter were applied to analyze membrane surface morphology, membrane material characteristics and membrane fouling for the original and fouled membranes. Based on the above analysis, the performance of the selected Gemini surfactant was proved superior in the following aspects: retention of phenol/surfactant (peak value is 95.8% for phenol retention), permeate flux and membrane fouling with respect to other conventional surfactants possessing equal alkyl chain length. These results demonstrated

  4. Micellar copolymerization of poly(acrylamide-g-propylene oxide): rheological evaluation and solution characterization; Copolimerizacao micelar de poli(acrilamida-g-oxido de propileno): avaliacao reologica e caracterizacao de suas solucoes

    Energy Technology Data Exchange (ETDEWEB)

    Sadicoff, Bianca L.; Brandao, Edimir M.; Lucas, Elizabete F. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Macromoleculas]. E-mail: elucas@ima.ufrj.br; Amorim, Marcia C.V. [Universidade Estadual, Rio de Janeiro, RJ (Brazil). Inst. de Quimica

    2001-06-01

    Graft copolymers of polyacrylamide and poly(propylene oxide) were synthesized by a micellar copolymerization technique. The rheological properties of the copolymers solutions were evaluated and compared with literature data for solutions of the same copolymers, synthesized by solution polymerization. The effect of hydrophobe content, salt addition and surfactant addition on the rheological properties were also investigated. Increasing hydrophobe content resulted in higher solution viscosities in the semi-dilute regime. Upon addition of salts, the hydrophobic groups associated to minimize their exposure to water. In the semi-dilute region, higher contents of surfactant added resulted in lower reduced viscosities of the polymer solutions. The copolymers were qualitatively characterized by infra-red spectrometry. (author)

  5. Application of micellar electrokinetic capillary chromatography for routine analysis of different materials

    Directory of Open Access Journals (Sweden)

    Injac Rade

    2008-01-01

    Full Text Available Micellar electrokinetic capillary chromatography (MEKC has become a popular mode among the several capillary electro-migration techniques. Most drug analysis can be performed by using MEKC because of its wide applicability. Separation of very complex mixtures, determination of drugs in the biological materials, etc., can be successfully achieved by MEKC. This review surveys typical applications of MEKC analysis. Recent advances in MEKC, especially with solid-phase extraction and large-volume sample stacking, are described. Modes of electrokinetic chromatography including MEKC, a separation theory of MEKC, environmental friendly analysis, and selectivity manipulation in MEKC are also briefly mentioned.

  6. The different-ligand complexing of europium with complexones and β-diketones in micellar solution

    International Nuclear Information System (INIS)

    Svetlova, I.E.; Dobrynina, N.A.; Smirnova, N.S.; Martynenko, L.I.; Evseev, A.M.; Savitskij, A.P.

    1989-01-01

    Method of pH-metric titration with mathematical simulation was used to study the effect of nonionic surfactant (polyoxyethyleneoctylphenyl este) on stability of europium complexes with cyclohexanediaminetetraacetic and ethylenediaminetetraacetic acids. Optimal conditions for ternary complex formation in the system Eu 3+ -complexone-β-diketone at pH 7.0-9.0 were found. Complex-compositions were determined and their stability constants were calculated. It is shown that complex stability decreases by several orders in micellar solutions, tecause β-diketone introduction to the solution decreases thermodynamic stability of complexes

  7. An Asymptotic Theory for the Re-Equilibration of a Micellar Surfactant Solution

    KAUST Repository

    Griffiths, I. M.; Bain, C. D.; Breward, C. J. W.; Chapman, S. J.; Howell, P. D.; Waters, S. L.

    2012-01-01

    Micellar surfactant solutions are characterized by a distribution of aggregates made up predominantly of premicellar aggregates (monomers, dimers, trimers, etc.) and a region of proper micelles close to the peak aggregation number, connected by an intermediate region containing a very low concentration of aggregates. Such a distribution gives rise to a distinct two-timescale reequilibration following a system dilution, known as the t1 and t2 processes, whose dynamics may be described by the Becker-Döring equations. We use a continuum version of these equations to develop a reduced asymptotic description that elucidates the behavior during each of these processes.© 2012 Society for Industrial and Applied Mathematics.

  8. Optimisation of resolution in micellar electrokinetic chromatography by multivariate evaluation of electrolytes.

    Science.gov (United States)

    Mikaeli, S; Thorsén, G; Karlberg, B

    2001-01-12

    A novel approach to multivariate evaluation of separation electrolytes for micellar electrokinetic chromatography is presented. An initial screening of the experimental parameters is performed using a Plackett-Burman design. Significant parameters are further evaluated using full factorial designs. The total resolution of the separation is calculated and used as response. The proposed scheme has been applied to the optimisation of the separation of phenols and the chiral separation of (+)-1-(9-anthryl)-2-propyl chloroformate-derivatized amino acids. A total of eight experimental parameters were evaluated and optimal conditions found in less than 48 experiments.

  9. The content changes of selected phenolic compounds during processing of medicinal plants

    OpenAIRE

    GROŠAFTOVÁ, Blanka

    2007-01-01

    This work was aimed to the problem of change of the content of selected phenolic substances during treatment and storage of medical plants. Flavonoids represent small, but very important group of phenolic compounds. The biggest attention was paid to quercetin and rutine.Content of phenolic substances was determined by method of micellar electrokinetic capillary chromatography (MECC) in case of 6 medicinal plants usually used in traditional and modern medicine.

  10. Determination of patulin in commercial apple juice by micellar electrokinetic chromatography.

    Science.gov (United States)

    Murillo, M; González-Peñas, E; Amézqueta, S

    2008-01-01

    A novel and validated micellar electrokinetic capillary chromatography (MEKC) method using ultraviolet detection (UV) has been applied to the quantitative analysis of patulin (PAT) in commercial apple juice. Patulin was extracted from samples with an ethylacetate solution. The micellar electrokinetic capillary chromatography (MECK) parameters studied for method optimization were buffer composition, voltage, temperature, and a separation between PAT and 5-hydroxymethylfurfural (HMF) (main interference in apple juice PAT analysis) peaks until reaching baseline. The method passes a series of validation tests including selectivity, linearity, limit of detection and quantification (0.7 and 2.5 microgL(-1), respectively), precision (within and between-day variability) and recovery (80.2% RSD=4%), accuracy, and robustness. This method was successfully applied to the measurement of 20 apple juice samples obtained from different supermarkets. One hundred percent of the samples were contaminated with a level greater than the limit of detection, with mean and median values of 41.3 and 35.7 microgL(-1), respectively.

  11. Dynamic and structural characterisation of micellar solutions of surfactants by spin relaxation and translational diffusion

    International Nuclear Information System (INIS)

    Mahieu, Nathalie

    1992-01-01

    The work reported in this research thesis aimed at characterizing micellar phases formed by some surfactants (sodium carboxylates) in aqueous solution. After some recalls on nuclear magnetic resonance dealing with spin relaxation (longitudinal relaxation, transverse relaxation, relaxation in the rotating coordinate system, and crossed relaxation), and comments on the dipolar mechanism responsible of relaxation phenomena, the author presents the methods used for relaxation parameter measurement and the data processing software issued from experiments. He presents experiments which allowed the self-diffusion coefficient to be measured, reports data processing, and addresses problems of special diffusion and of coherence transfers during diffusion measurements. Results of proton relaxation measurements are then presented and discussed. They are used to determine the micellar state of the studied carboxylates. The case of the oleate is also addressed. Measurements of carbon-13 relaxation times are reported, and exploited in terms of structural parameters by using the Relaxator software. An original method of the hetero-nuclear Overhauser method is presented, and used to assess the average distance between water molecules and micelle surface [fr

  12. Pt/glassy carbon model catalysts prepared from PS-b-P2VP micellar templates.

    Science.gov (United States)

    Gu, Yunlong; St-Pierre, Jean; Ploehn, Harry J

    2008-11-04

    Poly(styrene)-block-poly(2-vinylpyridine) (PS-b-P2VP) diblock copolymer was used as a micellar template to fabricate arrays of Pt nanoparticles on mica and glassy carbon (GC) supports. Polymer micellar deposition yields Pt nanoparticles with tunable particle size and surface number density on both mica and GC. After deposition of precursor-loaded micelles onto GC, oxygen plasma etching removes the polymer shell, followed by thermal treatment with H2 gas to reduce the Pt. Etching conditions were optimized to maximize removal of the polymer while minimizing damage to the GC. Arrays of Pt nanoparticles with controlled size and surface number density can be prepared on mica (for particle size characterization) and GC to make Pt/GC model catalysts. These model catalysts were characterized by tapping mode atomic force microscopy, X-ray photoelectron spectroscopy, and cyclic voltammetry to measure activity for oxidation of carbon monoxide or methanol. Cyclic voltammetry results demonstrate the existence of a correlation between Pt particle size and electrocatalytic properties including onset potential, tolerance of carbonaceous adsorbates, and intrinsic activity (based on active Pt area from CO stripping voltammetry). Results obtained with Pt/GC model catalysts duplicate prior results obtained with Pt/porous carbon catalysts therefore validating the synthesis approach and offering a new, tunable platform to study catalyst structure and other effects such as aging on proton exchange membrane fuel cell (PEMFC) reactions.

  13. Mechanistic Analysis of Cocrystal Dissolution as a Function of pH and Micellar Solubilization.

    Science.gov (United States)

    Cao, Fengjuan; Amidon, Gordon L; Rodriguez-Hornedo, Nair; Amidon, Gregory E

    2016-03-07

    The purpose of this work is to provide a mechanistic understanding of the dissolution behavior of cocrystals under the influence of ionization and micellar solubilization. Mass transport models were developed by applying Fick's law of diffusion to dissolution with simultaneous chemical reactions in the hydrodynamic boundary layer adjacent to the dissolving cocrystal surface to predict the pH at the dissolving solid-liquid interface (i.e., interfacial pH) and the flux of cocrystals. To evaluate the predictive power of these models, dissolution studies of carbamazepine-saccharin (CBZ-SAC) and carbamazepine-salicylic acid (CBZ-SLC) cocrystals were performed at varied pH and surfactant concentrations above the critical stabilization concentration (CSC), where the cocrystals were thermodynamically stable. The findings in this work demonstrate that the pH dependent dissolution behavior of cocrystals with ionizable components is dependent on interfacial pH. This mass transport analysis demonstrates the importance of pH, cocrystal solubility, diffusivity, and micellar solubilization on the dissolution rates of cocrystals.

  14. In situ synthesis of Prussian blue nanoparticles within a biocompatible reverse micellar system for in vivo Cs"+ uptake

    International Nuclear Information System (INIS)

    Lavaud, Cyril; Kajdan, Marilyn; Long, Jerome; Larionova, Joulia; Guari, Yannick; Compte, Elsa; Maurel, Jean-Claude; Him, Josephine Lai Kee; Bron, Patrick; Oliviero, Erwan

    2017-01-01

    A new highly stable Prussian blue reverse micellar system comprising ultra-small Prussian blue nanoparticles in Aonyss (Peceolt, b-sitosterol, lecithin, ethanol and water) acts as an in vivo Cs"+ uptake agent presenting higher efficiency compared to commercially available Prussian blue treatment with a significant dose effect. (authors)

  15. Comparison of migration modeling in micellar electrokinetic chromatography by linear regression and by use of an artificial neural network

    NARCIS (Netherlands)

    Metting, HJ; van Zomeren, PV; van der Ley, CP; Coenegracht, PMJ; de Jong, GJ

    2000-01-01

    The concentrations of modifier (methanol or acetonitrile) and surfactant (sodium dodecyl sulfate SDS) in the running buffer are important factors influencing the mobility of analytes in micellar electrokinetic chromatography (MEKC). Response surfaces of the effective mobility can be used to predict

  16. Thermodynamic analysis of unimer-micelle and sphere-to-rod micellar transitions of aqueous solutions of sodium dodecylbenzenesulfonate

    International Nuclear Information System (INIS)

    Valente, Artur J.M.; López Cascales, J.J.; Fernández Romero, Antonio J.

    2014-01-01

    Highlights: • Unimer-micelle and sphere-to-rod micellar transitions were observed to sodium dodecylbenzenesulfonate in aqueous solutions. • Two micellar transitions were seen by electrical conductivity and surface tension. • An anomalous ΔS 0 and ΔH 0 increase with T was found for the second critical transition. • More stable aggregates are evidenced for spherical micelles than for the other shapes. - Abstract: Temperature dependence of specific conductivity of sodium dodecylbenzenesulfonate (NaDBS) aqueous solutions was analyzed. Two breaks on the plot appeared for all temperature, which suggest two micellar transitions. This has been corroborated by surface tension measurements. The first transition concentration occurs at the critical micelle concentration (CMC), whilst the second critical concentration (so-called transition micellar concentration, TMC) is due to a sphere-to-rod micelles transition. The dependence of CMC and TMC on the temperature allows the computation of the corresponding thermodynamic functions: Gibbs free energy, enthalpy and entropy changes. For the CMC, enthalpy and entropy increments were found that decrease with the temperature values. However, an anomalous behavior was obtained for the TMC, where both ΔS 0 and ΔH 0 values raised with the temperature increase. However, for both transitions, an (enthalpy + entropy) compensation is observed. These results will be compared with similar systems reported in the literature

  17. Correlation between the solubility of aromatic hydrocarbons in water and micellar solutions, with their normal boiling points

    International Nuclear Information System (INIS)

    Almgren, M.; Grieser, F.; Powell, J.R.; Thomas, J.K.

    1979-01-01

    A linear correlation between the logarithm of the solubility in water of aromatic hydrocarbons and their normal boiling points is shown. Similarly, the logarithm of the distribution ratio of aromatic hydrocarbons in aqueous micellar solution is shown to be linearly related to the boiling points of the hydrocarbons. 2 figures, 2 tables

  18. Multicompartment micellar aggregates of linear ABC amphiphiles in solvents selective for the C block: A Monte Carlo simulation

    KAUST Repository

    Zhu, Yutian

    2012-01-01

    In the current study, we applied the Monte Carlo method to study the self-assembly of linear ABC amphiphiles composed of two solvophobic A and B blocks and a solvophilic C block. A great number of multicompartment micelles are discovered from the simulations and the detailed phase diagrams for the ABC amphiphiles with different block lengths are obtained. The simulation results reveal that the micellar structure is largely controlled by block length, solvent quality, and incompatibility between the different block types. When the B block is longer than or as same as the terminal A block, a rich variety of micellar structures can be formed from ABC amphiphiles. By adjusting the solvent quality or incompatibility between the different block types, multiple morphological transitions are observed. These morphological sequences are well explained and consistent with all the previous experimental and theoretical studies. Despite the complexity of the micellar structures and morphological transitions observed for the self-assembly of ABC amphiphiles, two important common features of the phase behavior are obtained. In general, the micellar structures obtained in the current study can be divided into zero-dimensional (sphere-like structures, including bumpy-surfaced spheres and sphere-on-sphere structures), one-dimensional (cylinder-like structures, including rod and ring structures), two-dimensional (layer-like structures, including disk, lamella and worm-like and hamburger structures) and three-dimensional (vesicle) structures. It is found that the micellar structures transform from low- to high- dimensional structures when the solvent quality for the solvophobic blocks is decreased. In contrast, the micellar structures transform from high- to low-dimensional structures as the incompatibility between different block types increases. Furthermore, several novel micellar structures, such as the CBABC five-layer vesicle, hamburger, CBA three-layer ring, wormlike shape with

  19. Study of micellar solutions of the 'sodium lauryl sulphate-heavy water' system by using pulsed NMR

    International Nuclear Information System (INIS)

    Fouchet, C.

    1972-01-01

    This research thesis reports the study of the nuclear magnetic resonance of protons contained by micellar solutions of sodium lauryl sulphate and heavy water. Relaxation times have been measured with respect to various parameters: concentration, temperature, frequency. The author presents the main properties of micellar solutions and indicate the various possible movements. Then, he addresses the implemented technique, and shows that NMR is sensitive to short range interactions, and allows micellar movements to be studied over an extended rate range. Experimental results are then presented and interpreted [fr

  20. Flow-induced immobilization of glucose oxidase in nonionic micellar nanogels for glucose sensing.

    Science.gov (United States)

    Cardiel, Joshua J; Zhao, Ya; Tonggu, Lige; Wang, Liguo; Chung, Jae-Hyun; Shen, Amy Q

    2014-10-21

    A simple microfluidic platform was utilized to immobilize glucose oxidase (GOx) in a nonionic micellar scaffold. The immobilization of GOx was verified by using a combination of cryogenic electron microscopy (cryo-EM), scanning electron microscopy (SEM), and ultraviolet spectroscopy (UV) techniques. Chronoamperometric measurements were conducted on nanogel-GOx scaffolds under different glucose concentrations, exhibiting linear amperometric responses. Without impacting the lifetime and denaturation of GOx, the nonionic nanogel provides a favorable microenvironment for GOx in biological media. This flow-induced immobilization method in a nonionic nanogel host matrix opens up new pathways for designing a simple, fast, biocompatible, and cost-effective process to immobilize biomolecules that are averse to ionic environments.

  1. Amplification of Chirality through Self-Replication of Micellar Aggregates in Water

    KAUST Repository

    Bukhriakov, Konstantin

    2015-03-17

    We describe a system in which the self-replication of micellar aggregates results in a spontaneous amplification of chirality in the reaction products. In this system, amphiphiles are synthesized from two "clickable" fragments: a water-soluble "head" and a hydrophobic "tail". Under biphasic conditions, the reaction is autocatalytic, as aggregates facilitate the transfer of hydrophobic molecules to the aqueous phase. When chiral, partially enantioenriched surfactant heads are used, a strong nonlinear induction of chirality in the reaction products is observed. Preseeding the reaction mixture with an amphiphile of one chirality results in the amplification of this product and therefore information transfer between generations of self-replicating aggregates. Because our amphiphiles are capable of catalysis, information transfer, and self-assembly into bounded structures, they present a plausible model for prenucleic acid "lipid world" entities. © 2015 American Chemical Society.

  2. A photochemical study of uranyl ion interaction with the Triton X-100 micellar system

    International Nuclear Information System (INIS)

    Das, S.K.; Ganguly, B.N.

    1996-01-01

    This is a report on the spectroscopic characteristics of UO 2 2+ in the excited state in Triton X-100 micellar medium. It also indicates some important results of viscosity and surface tension measurements of the system which have direct relevance to the spectroscopic investigation in the excited state. The quenching of the UO 2 2+ fluorescence due to Triton X-100, upon micellization in the aqueous medium, reveals two kinds of microenvironments of the fluorophore from the Stern-Volmer plot. This has been verified by flash photolytic measurements. A blue shift of the quenched emission spectrum is ascribed to the collisional encounter of UO 2 1 + with the head groups of Triton X-100

  3. Profluorescent PPV-Based Micellar System as a Versatile Probe for Bioimaging and Drug Delivery.

    Science.gov (United States)

    Zaquen, Neomy; Lu, Hongxu; Chang, Teddy; Mamdooh, Russel; Lutsen, Laurence; Vanderzande, Dirk; Stenzel, Martina; Junkers, Thomas

    2016-12-12

    Although micelles are commonly used for drug delivery purposes, their long-term fate is often unknown due to photobleaching of the fluorescent labels or the use of toxic materials. Here, we present a metal-free, nontoxic, nonbleaching, fluorescent micelle that can address these shortcomings. A simple, yet versatile, profluorescent micellar system, built from amphiphilic poly(p-phenylenevinylene) (PPV) block copolymers, for use in drug delivery applications is introduced. Polymer micelles made from PPV show excellent stability for up to 1 year and are successfully loaded with anticancer drugs (curcumin or doxorubicin) without requiring introduction of physical or chemical cross-links. The micelles are taken up efficiently by the cells, which triggers disassembly, releasing the encapsulated material. Disassembly of the micelles and drug release is conveniently monitored as fluorescence of the single polymer chains appear, which enables not only to monitor the release of the payload, but in principle also the fate of the polymer over longer periods of time.

  4. Enantioseparation of palonosetron hydrochloride by micellar electrokinetic chromatography with sodium cholate as chiral selector.

    Science.gov (United States)

    Tian, Kan; Chen, Hongli; Tang, Jianghong; Chen, Xingguo; Hu, Zhide

    2006-11-03

    The enantioseparation of four stereoisomers of palonosetron hydrochloride by micellar electrokinetic chromatography using sodium cholate as chiral surfactant was described. Sodium cholate was shown to be effective in separating palonosetron hydrochloride stereoisomers. For method optimization, several parameters such as sodium cholate concentration, buffer pH and concentration, the types and concentration of organic modifiers and applied voltage, on the enantioseparation were evaluated and the optimum conditions were obtained as follows: 30 mM borate buffer (pH 9.40) containing 70 mM sodium cholate and 20% (v/v) methanol with an applied voltage of 20 kV. Under these conditions, baseline separation of palonosetron hydrochloride stereoisomers was achieved within 18 min.

  5. Importance of critical micellar concentration for the prediction of solubility enhancement in biorelevant media.

    Science.gov (United States)

    Ottaviani, G; Wendelspiess, S; Alvarez-Sánchez, R

    2015-04-06

    This study evaluated if the intrinsic surface properties of compounds are related to the solubility enhancement (SE) typically observed in biorelevant media like fasted state simulated intestinal fluids (FaSSIF). The solubility of 51 chemically diverse compounds was measured in FaSSIF and in phosphate buffer and the surface activity parameters were determined. This study showed that the compound critical micellar concentration parameter (CMC) correlates strongly with the solubility enhancement (SE) observed in FaSSIF compared to phosphate buffer. Thus, the intrinsic capacity of molecules to form micelles is also a determinant for each compound's affinity to the micelles of biorelevant surfactants. CMC correlated better with SE than lipophilicity (logD), especially over the logD range typically covered by drugs (2 < logD < 4). CMC can become useful to guide drug discovery scientists to better diagnose, improve, and predict solubility in biorelevant media, thereby enhancing oral bioavailability of drug candidates.

  6. Binding of chloroquine to ionic micelles: Effect of pH and micellar surface charge

    Energy Technology Data Exchange (ETDEWEB)

    Souza Santos, Marcela de, E-mail: marcelafarmausp77@gmail.com [Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Avenida do Café, s/n, Ribeirão Preto, São Paulo 14040-903 (Brazil); Perpétua Freire de Morais Del Lama, Maria, E-mail: mpemdel@fcfrp.usp.br [Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Avenida do Café, s/n, Ribeirão Preto, São Paulo 14040-903 (Brazil); Instituto Nacional de Ciência e Tecnologia de Bioanalítica, Departamento de Química Analítica, Universidade Estadual de Campinas, Cidade Universitária Zeferino Vaz, s/n, Campinas, São Paulo 13083-970 (Brazil); Siuiti Ito, Amando, E-mail: amandosi@ffclrp.usp.br [Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes, 3900, Ribeirão Preto, São Paulo 14040-901 (Brazil); and others

    2014-03-15

    The pharmacological action of chloroquine relies on its ability to cross biological membranes in order to accumulate inside lysosomes. The present work aimed at understanding the basis for the interaction between different chloroquine species and ionic micelles of opposite charges, the latter used as a simple membrane model. The sensitivity of absorbance and fluorescence of chloroquine to changes in its local environment was used to probe its interaction with cetyltrimethylammonium micelles presenting bromide (CTAB) and sulfate (CTAS) as counterions, in addition to dodecyl sulfate micelles bearing sodium (SDS) and tetramethylammonium (TMADS) counterions. Counterion exchange was shown to have little effect on drug–micelle interaction. Chloroquine first dissociation constant (pKa{sub 1}) shifted to opposite directions when anionic and cationic micelles were compared. Chloroquine binding constants (K{sub b}) revealed that electrostatic forces mediate charged drug–micelle association, whereas hydrophobic interactions allowed neutral chloroquine to associate with anionic and cationic micelles. Fluorescence quenching studies indicated that monoprotonated chloroquine is inserted deeper into the micelle surface of anionic micelles than its neutral form, the latter being less exposed to the aqueous phase when associated with cationic over anionic assemblies. The findings provide further evidence that chloroquine–micelle interaction is driven by a tight interplay between the drug form and the micellar surface charge, which can have a major effect on the drug biological activity. -- Highlights: • Chloroquine (CQ) pKa{sub 1} increased for SDS micelles and decreased for CTAB micelles. • CQ is solubilized to the surface of both CTAB and SDS micelles. • Monoprotonated CQ is buried deeper into SDS micelles than neutral CQ. • Neutral CQ is less exposed to aqueous phase in CTAB over SDS micelles. • Local pH and micellar surface charge mediate interaction of CQ with

  7. Structural changes induced by high-pressure processing in micellar casein and milk protein concentrates.

    Science.gov (United States)

    Cadesky, Lee; Walkling-Ribeiro, Markus; Kriner, Kyle T; Karwe, Mukund V; Moraru, Carmen I

    2017-09-01

    Reconstituted micellar casein concentrates and milk protein concentrates of 2.5 and 10% (wt/vol) protein concentration were subjected to high-pressure processing at pressures from 150 to 450 MPa, for 15 min, at ambient temperature. The structural changes induced in milk proteins by high-pressure processing were investigated using a range of physical, physicochemical, and chemical methods, including dynamic light scattering, rheology, mid-infrared spectroscopy, scanning electron microscopy, proteomics, and soluble mineral analyses. The experimental data clearly indicate pressure-induced changes of casein micelles, as well as denaturation of serum proteins. Calcium-binding α S1 - and α S2 -casein levels increased in the soluble phase after all pressure treatments. Pressurization up to 350 MPa also increased levels of soluble calcium and phosphorus, in all samples and concentrations, whereas treatment at 450 MPa reduced the levels of soluble Ca and P. Experimental data suggest dissociation of calcium phosphate and subsequent casein micelle destabilization as a result of pressure treatment. Treatment of 10% micellar casein concentrate and 10% milk protein concentrate samples at 450 MPa resulted in weak, physical gels, which featured aggregates of uniformly distributed, casein substructures of 15 to 20 nm in diameter. Serum proteins were significantly denatured by pressures above 250 MPa. These results provide information on pressure-induced changes in high-concentration protein systems, and may inform the development on new milk protein-based foods with novel textures and potentially high nutritional quality, of particular interest being the soft gel structures formed at high pressure levels. The Authors. Published by the Federation of Animal Science Societies and Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

  8. Effect of tartarate and citrate based food additives on the micellar properties of sodium dodecylsulfate for prospective use as food emulsifier.

    Science.gov (United States)

    Banipal, Tarlok S; Kaur, Harjinder; Kaur, Amanpreet; Banipal, Parampaul K

    2016-01-01

    Citrate and tartarate based food preservatives can be used to enhance the emulsifying properties of sodium dodecylsulfate (SDS) based micellar system and thus making it appropriate for food applications. Exploration of interactions between the two species is the key constraint for execution of such ideas. In this work various micellar and thermodynamic parameters of SDS like critical micellar concentration (CMC), standard Gibbs free energy of micellization (ΔG(0)mic.) etc. have been calculated in different concentrations of disodium tartarate (DST) and trisodium citrate (TSC) in the temperature range (288.15-318.15)K from the conductivity and surface tension measurements. The parameters obtained from these studies reveal the competitive nature of both the additives with SDS for available positions at the air/water interface. TSC is found to be more effective additive in order to make SDS micellar system better for its potential applications as food emulsifier. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Reverse micellar synthesis, structural characterization and dielectric properties of Sr-doped BaZrO_3 nanoparticles

    International Nuclear Information System (INIS)

    Ahmad, Tokeer; Ubaidullah, Mohd; Shahazad, Mohd; Kumar, Dinesh; Al-Hartomy, Omar A.

    2017-01-01

    Sr-doped BaZrO_3 nanoparticles with strontium content varying from 5 to 20 mol % were successfully synthesized by reverse micellar method at 900 °C for the first time. Systematic studies have been carried out to establish the structural and electrical properties of the as prepared nanoparticles. These nanoparticles were characterized using powder X-ray diffraction, transmission electron microscopy, BET surface area and dielectric measurements. X-ray diffraction analysis showed the formation of monophasic and highly crystalline nanoparticles which could be indexed in cubic BaZrO_3 with contraction of lattice on strontium substitution. A monotonic shift of diffraction pattern towards higher angel confirms the formation of solid solutions of Ba_1_−_xSr_xZrO_3 (0.05 ≤ x ≤ 0.20) which was corroborating well with lattice parameter studies. Transmission electron microscopic studies showed the formation of cubic, spherical and hexagonal nanoparticles with an average grain size of 40–65 nm. Energy dispersive X-ray spectroscopic studies confirmed the presence of dopant (Sr"2"+) in the BaZrO_3 matrix and estimated chemical species corroborate well with the loaded composition. Specific surface area of the solid solution comes out to be in the range of 104–244 m"2 g"-"1. Smallest particle of size 40 nm shows highest surface area 244 m"2 g"-"1 for 20 mol% Sr-doped BaZrO_3. Dielectric and impedance studies were also carried out as a function of frequency and temperature to explore the electrical properties of Sr-doped BaZrO_3. The dielectric constant of Ba_1_−_xSr_xZrO_3 (0.05 ≤ x ≤ 0.20) was found to be in the range of 13–25 for x = 0.05 to x = 0.20 with nearly similar dielectric loss of the order of 0.02. The conductance increases linearly with increase in frequency at room temperature, however the impedance has an inverse effect. - Highlights: • Monophasic nanocrystalline Ba_1_−_xSr_xZrO_3 at low dopant concentration using reverse micelles for the first

  10. Reverse micellar synthesis, structural characterization and dielectric properties of Sr-doped BaZrO{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Tokeer, E-mail: tahmad3@jmi.ac.in [Nanochemistry Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi, 110025 (India); Ubaidullah, Mohd [Nanochemistry Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi, 110025 (India); Department of Chemistry, Banasthali University, Tonk, Rajasthan, 304022 (India); School of Science and Technology, Glocal University, Mirzapur, Saharanpur, 247121, Uttar Pradesh (India); Shahazad, Mohd [Nanochemistry Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi, 110025 (India); Kumar, Dinesh [Department of Chemistry, Banasthali University, Tonk, Rajasthan, 304022 (India); Al-Hartomy, Omar A. [Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah, 21589 (Saudi Arabia)

    2017-01-01

    Sr-doped BaZrO{sub 3} nanoparticles with strontium content varying from 5 to 20 mol % were successfully synthesized by reverse micellar method at 900 °C for the first time. Systematic studies have been carried out to establish the structural and electrical properties of the as prepared nanoparticles. These nanoparticles were characterized using powder X-ray diffraction, transmission electron microscopy, BET surface area and dielectric measurements. X-ray diffraction analysis showed the formation of monophasic and highly crystalline nanoparticles which could be indexed in cubic BaZrO{sub 3} with contraction of lattice on strontium substitution. A monotonic shift of diffraction pattern towards higher angel confirms the formation of solid solutions of Ba{sub 1−x}Sr{sub x}ZrO{sub 3} (0.05 ≤ x ≤ 0.20) which was corroborating well with lattice parameter studies. Transmission electron microscopic studies showed the formation of cubic, spherical and hexagonal nanoparticles with an average grain size of 40–65 nm. Energy dispersive X-ray spectroscopic studies confirmed the presence of dopant (Sr{sup 2+}) in the BaZrO{sub 3} matrix and estimated chemical species corroborate well with the loaded composition. Specific surface area of the solid solution comes out to be in the range of 104–244 m{sup 2} g{sup -1}. Smallest particle of size 40 nm shows highest surface area 244 m{sup 2} g{sup -1} for 20 mol% Sr-doped BaZrO{sub 3}. Dielectric and impedance studies were also carried out as a function of frequency and temperature to explore the electrical properties of Sr-doped BaZrO{sub 3}. The dielectric constant of Ba{sub 1−x}Sr{sub x}ZrO{sub 3} (0.05 ≤ x ≤ 0.20) was found to be in the range of 13–25 for x = 0.05 to x = 0.20 with nearly similar dielectric loss of the order of 0.02. The conductance increases linearly with increase in frequency at room temperature, however the impedance has an inverse effect. - Highlights: • Monophasic nanocrystalline Ba{sub 1

  11. Determination of phthalic acid esters in Chinese white spirit using dispersive liquid-liquid microextraction coupled with sweeping β-cyclodextrin-modified micellar electrokinetic chromatography.

    Science.gov (United States)

    Sun, Jianzhi; He, Hui; Liu, Shuhui

    2014-07-01

    A simple method that consumes low organic solvent is proposed for the analysis of phthalic acid esters in Chinese white spirit using dispersive liquid-liquid microextraction coupled with sweeping-micellar electrokinetic chromatography. Tetrachloromethane and white-spirit-containing ethanol were used as the extraction and dispersing solvents, respectively. The electrophoresis separation buffer was composed of 5 mM β-cyclodextrin, 50 mM sodium dodecyl sulfate and 25 mM borate buffer (pH 9.2) with 9% acetonitrile, enabling the baseline resolution of the analytes within 13 min. Under the optimum conditions, satisfactory linearities (5-1000 ng/mL, r ≥ 0.9909), good reproducibility (RSD ≤ 6.7% for peak area, and RSD ≤ 2.8% for migration time), low detection limits (0.4-0.8 ng/mL) and acceptable recovery rates (89.6-105.7%) were obtained. The proposed method was successfully applied to 22 Chinese white spirits, and the content of dibutyl phthalate in 55% of the samples exceeded the Specific Migration Limit of 0.3 mg/kg established by the domestic and international regulations. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Spectroscopic Behavior of Some A3B Type Tetrapyrrolic Complexes in Several Organic Solvents and Micellar Media

    Directory of Open Access Journals (Sweden)

    Radu Socoteanu

    2011-08-01

    Full Text Available The paper presents spectral studies of some unsymmetrical A3B tetrapyrrolic, porphyrin-type complexes with Cu(II and Zn(II in different solvents and micellar media aimed at estimating their properties in connection with the living cell. The results indicate that the position of the absorption and emission peaks is mostly influenced by the central metal ion and less by the environmental polarity or the peripheric substituents of the porphyrinic core. The comparison between the overall absorption and emission spectra of the compounds in methanol or cyclohexane vs. direct and reverse Triton X micellar systems, respectively, suggests for all compounds the localization at the interface between the polyethylene oxide chains and the tert-octyl-phenyl etheric residue of the Triton X-100 molecules. These findings could be important when testing the compounds embedded in liposomes or other delivery systems to the targeted cell.

  13. Chiral separation of amino acids in biological fluids by micellar electrokinetic chromatography with laser-induced fluorescence detection.

    Science.gov (United States)

    Thorsén, G; Bergquist, J

    2000-08-18

    A method is presented for the chiral analysis of amino acids in biological fluids using micellar electrokinetic chromatography (MEKC) and laser-induced fluorescence (LIF). The amino acids are derivatized with the chiral reagent (+/-)-1-(9-anthryl)-2-propyl chloroformate (APOC) and separated using a mixed micellar separation system. No tedious pre-purification of samples is required. The excellent separation efficiency and good detection capabilities of the MEKC-LIF system are exemplified in the analysis of urine and cerebrospinal fluid. This is the first time MEKC has been reported for chiral analysis of amino acids in biological fluids. The amino acids D-alanine, D-glutamine, and D-aspartic acid have been observed in cerebrospinal fluid, and D-alanine and D-glutamic acid in urine. To the best of our knowledge no measurements of either D-alanine in cerebrospinal fluid or D-glutamic acid in urine have been presented in the literature before.

  14. Effect of micellar collisions and polyvinylpyrrolidone confinement on the electrical conductivity percolation parameters of water/AOT/isooctane reverse micelles

    Science.gov (United States)

    Guettari, Moez; Aferni, Ahmed E. L.; Tajouri, Tahar

    2017-12-01

    The main aim of this paper is the analysis of micellar collisions and polymer confinement effects on the electrical conductivity percolative behavior of water/sodium bis(2-ethylhexyl) sulfosuccinate (AOT)/isooctane reverse micelles. Firstly, we have performed conductance measurements of the system for three AOT to isooctane volume ratio, φm = 0.1 , 0.15 and 0.2 to examine the influence of micellar collisions on the percolation parameters. All the measurements were carried out over the 298.15 K-333.15 K temperature range at a fixed water to AOT molar ratio, W0 = 45 . We have assessed that the rise of micellar collisions frequency enhances the conductance percolation. Secondly, the confinement effect of a water-soluble polymer, polyvinylpyrrolidone (PVP), on the reverse micelles conductance behavior was investigated. Temperature-induced percolation, Tp , have shown a dependence on the polymer concentration, CPVP . It was also observed that for various PVP concentrations, the activation energy of percolation decreases. Finally, the values of the critical exponents determined in the presence and absence of PVP prove that the polymer affects the dynamic of percolation.

  15. Spectroscopic studies on the molecular interaction between salicylic acid and riboflavin (B{sub 2}) in micellar solution

    Energy Technology Data Exchange (ETDEWEB)

    Bhattar, S.L.; Kolekar, G.B. [Fluorescence Spectroscopy Research Laboratory, Department of Chemistry, Shivaji University, Kolhapur-416 004, Maharashtra (India); Patil, S.R., E-mail: srp_fsl@rediffmail.co [Fluorescence Spectroscopy Research Laboratory, Department of Chemistry, Shivaji University, Kolhapur-416 004, Maharashtra (India)

    2010-03-15

    The interaction between salicylic acid (SA) and riboflavin (RF) was studied by Fluorescence Resonance Energy Transfer (FRET) in micellar solution. The riboflavin strongly quenches the intrinsic fluorescence of SA by radiative energy transfer. The extent of energy transfer in sodium dodecyl sulphate (SDS) micellar solution of different concentration is quantified from the energy transfer efficiency data. It is seen that the energy transfer is more efficient in the micellar solution. The critical energy transfer distance (R{sub 0}) was determined from which the mean distance between SA and RF molecules was calculated. The quenching was found to fit into Stern-Volmer relation. The results on variation of Stern-Volmer constant (K{sub sv}) with quencher concentration obtained at different temperatures suggested the formation of complex between SA and RF. The association constant of complex formation was estimated and found to decrease with temperature. The values of thermodynamic parameters DELTAH, DELTAG and DELTAS at different temperatures were estimated and the results indicated that the molecular interaction between SA and RF is electrostatic in nature.

  16. Current trends in the use of vitamin E-based micellar nanocarriers for anticancer drug delivery.

    Science.gov (United States)

    Muddineti, Omkara Swami; Ghosh, Balaram; Biswas, Swati

    2017-06-01

    Owing to the complexity of cancer pathogenesis, conventional chemotherapy can be an inadequate method of killing cancer cells effectively. Nanoparticle-based drug delivery systems have been widely exploited pre-clinically in recent years. Areas covered: Incorporation of vitamin-E in nanocarriers have the advantage of (1) improving the hydrophobicity of the drug delivery system, thereby improving the solubility of the loaded poorly soluble anticancer drugs, (2) enhancing the biocompatibility of the polymeric drug carriers, and (3) improving the anticancer potential of the chemotherapeutic agents by reversing the cellular drug resistance via simultaneous administration. In addition to being a powerful antioxidant, vitamin E demonstrated its anticancer potential by inducing apoptosis in various cancer cell lines. Various vitamin E analogs have proven their ability to cause marked inhibition of drug efflux transporters. Expert opinion: The review discusses the potential of incorporating vitamin E in the polymeric micelles which are designed to carry poorly water-soluble anticancer drugs. Current applications of various vitamin E-based polymeric micelles with emphasis on the use of α-tocopherol, D-α-tocopheryl succinate (α-TOS) and its conjugates such as D-α-tocopheryl polyethylene glycol-succinate (TPGS) in micellar system is delineated. Advantages of utilizing polymeric micelles for drug delivery and the challenges to treat cancer, including multiple drug resistance have been discussed.

  17. Determination of Sodium deoxycolate residues in vaccinal formulation by micellar electrokinetic chromatography

    International Nuclear Information System (INIS)

    Merchan, Yaima; Lucangioli, Silvia; Carducci, Clyde

    2011-01-01

    The sodium deoxycholate (DCNa) source is the surfactant used in the biopharmaceutical industry for the solubilization of outer membrane vesicles. It is well known the importance of control of this metabolite in biological materials due to its high toxicity for humans. To demonstrate significant small variations of this metabolite in vaccine formulations it is necessary to use a methodology highly selective, sensitive, specific and reproducible. In this report we used the micellar electrokinetic chromatography (MEKC) in a Capillary Ion Analyzer (Water corp. Milford MA) detection at 185 nm mercury lamp. It employed a fused silica capillary uncoated (Waters Corp. Milford MA). We assessed the purity of 2 lots of sodium deoxycholate and analyzed 15 samples of purified vesicles active pharmaceutical ingredient vaccine formulations. Data were recorded and processed with software Millennium TM (Waters Corp. Milford MA). It was found that lots of sodium deoxycholate containing 1.19 and 0.44% cholic acid and contaminate that 93% of the purified vesicles samples were from 0 to 2.44 mg protein DCNa/100 μg. MECK's results were compared with a kinetic test used to determine bile acids in blood (Merckotest). MECK system showed better results regarding the Merkotest

  18. Determination of Critical Micellar Concentration of Homologous 2-Alkoxyphenylcarbamoyloxyethyl-Morpholinium Chlorides

    Directory of Open Access Journals (Sweden)

    Lenka Stopková

    2018-05-01

    Full Text Available The critical micellar concentrations of selected alkyloxy homologues of local anesthetic 4-(2-{[(2-alkoxyphenylcarbamoyl]oxy}ethylmorpholin-4-ium chloride with nc = 2, 4, 5, 6, 7, 8, and 9 carbons in alkyloxy tail were determined by absorption spectroscopy in the UV–vis spectral region with the use of a pyrene probe. Within the homologous series of the studied amphiphilic compounds, the ln(cmc was observed to be dependent linearly on the number of carbon atoms nc in the hydrophobic tail: ln(cmc = 0.705–0.966 nc. The Gibbs free energy, necessary for the transfer of the methylene group of the alkoxy chain from the water phase into the inner part of the micelle at the temperature of 25 °C and pH ≈ 4.5–5.0, was found to be −2.39 kJ/mol. The experimentally determined cmc values showed good correlations with the predicted values of the bulkiness of the alkoxy tail expressed as the molar volume of substituent R, as well as with the surface tension of the compounds.

  19. Micellar Liquid Chromatographic Determination of Carbaryl and 1-Naphthol in Water, Soil, and Vegetables

    Directory of Open Access Journals (Sweden)

    Mei-Liang Chin-Chen

    2012-01-01

    Full Text Available A liquid chromatographic procedure has been developed for the determination of carbaryl, a phenyl-N-methylcarbamate, and its main metabolite 1-naphthol, using a C18 column (250’mm’ × ’4.6’mm with a micellar mobile phase and fluorescence detection at maximum excitation/emission wavelengths of 225/333’nm, respectively. In the optimization step, surfactants sodium dodecyl sulphate (SDS, Brij-35 and N-cetylpyridinium chloride monohydrate, and organic solvents propanol, butanol, and pentanol were considered. The selected mobile phase was 0.15’M SDS-6% (v/v-pentanol-0.01’M NaH2PO4 buffered at pH 3. Validation studies, according to the ICH Tripartite Guideline, included linearity (r>0.999, limit of detection (5 and 18’ng mL-1, for carbaryl and 1-naphthol, resp., and limit of quantification (15 and 50’ng mL-1, for carbaryl and 1-naphthol, resp., with intra- and interday precisions below 1%, and robustness parameters below 3%. The results show that the procedure was adequate for the routine analysis of these two compounds in water, soil, and vegetables samples.

  20. Modulating Pluronics micellar rupture with cyclodextrins and drugs: effect of pH and temperature

    International Nuclear Information System (INIS)

    Valero, M; Dreiss, C A

    2014-01-01

    Micelles of the triblock copolymer Pluronic F127 can encapsulate drugs with various chemical structures and their architecture has been studied by small-angle neutron scattering (SANS). Interaction with a derivative of β-cyclodextrin, namely, heptakis(2,6-di-O- methyl)-β-cyclodextrin (DIMEB), induces a complete break-up of the micelles, providing a mechanism for drug release. In the presence of drugs partitioned within the micelles, competitive interactions between polymer, drug and cyclodextrin lead to a modulation of the micellar rupture, depending on the nature of the drug and the exact composition of the ternary system. These interactions can be further adjusted by temperature and pH. While the most widely accepted mechanism for the interaction between Pluronics and cyclodextrins is through polypseudorotaxane (PR) formation, involving the threading of β-CD on the polymer backbone, time-resolved SANS experiments show that de-micellisation takes place in less than 100 ms, thus unambiguously ruling out an inclusion complex between the cyclodextrin and the polymer chains

  1. Biocatalytic synthesis of polymeric nanowires by micellar templates of ionic surfactants

    International Nuclear Information System (INIS)

    Nazari, K.; Adhami, F.; Najjar-Safari, A.; Salmani, S.; Mahmoudi, A.

    2011-01-01

    Highlights: → Soft-template production of polyguaiacol nanowire was done by peroxidase enzyme. → Main advantage of this simple method is producing soluble encapsulated nanowires. → Nanowire can be easily precipitated and separated by dilution with distilled water. → Size tuned templates of sodium decyl sulfate (d = 2.7 nm) gave nanowires with d = 2-4 nm. → Dried surfactant-coated wires recover freshly on specified and desired applications. -- Abstract: Micelle-templated polyguaiacol nanowires were successfully prepared via polymerization oxidation of guaiacol (o-methoxy phenol) by peroxidase enzyme in the presence of hydrogen peroxide at mild reaction conditions. The dimensions of the prepared nanowires were controlled by tuning the size and shape of the micelle structure via changing and controlling the type, chain length and molar concentrations of the ionic surfactant. The progress of the reaction and estimation of the size of soft micellar templates were followed by UV-Vis spectroscopy and dynamic light scattering (DLS). The resulting micelle encapsulated or purified polyguaiacol nanowires were characterized using transmission electron microscopy (TEM).

  2. Thermosetting microemulsions and mixed micellar solutions as drug delivery systems for periodontal anesthesia.

    Science.gov (United States)

    Scherlund, M; Malmsten, M; Holmqvist, P; Brodin, A

    2000-01-20

    In the present study, thermosetting microemulsions and mixed micellar solutions were investigated as drug delivery systems for anesthetizing the periodontal pocket. The structure of the systems, consisting of the active ingredients lidocaine and prilocaine, as well as two block copolymers (Lutrol F127 and Lutrol F68), was investigated by NMR spectroscopy and photon correlation spectroscopy (PCS). The results obtained for dilute (1-3% w/w) solutions show discrete micelles with a diameter of 20-30 nm and a critical micellization temperature of 25-35 degrees C. Gel permeation chromatography (GPC) was used to study the distribution of the active ingredients, and indicates a preferential solubilization of the active components in micelles over unimers. Analogous to the Lutrol F127 single component system these formulations display an abrupt gelation on increasing temperature. The gelation temperature was found to depend on both the drug ionization and concentration. These systems have several advantages over emulsion-based formulations including good stability, ease of preparation, increased drug release rate, and improved handling due to the transparency of the formulations.

  3. Polymeric micellar pH-sensitive drug delivery system for doxorubicin.

    Science.gov (United States)

    Hrubý, Martin; Konák, Cestmír; Ulbrich, Karel

    2005-03-02

    A novel polymeric micellar pH-sensitive system for delivery of doxorubicin (DOX) is described. Polymeric micelles were prepared by self-assembly of amphiphilic diblock copolymers in aqueous solutions. The copolymers consist of a biocompatible hydrophilic poly(ethylene oxide) (PEO) block and a hydrophobic block containing covalently bound anthracycline antibiotic DOX. The starting block copolymers poly(ethylene oxide)-block-poly(allyl glycidyl ether) (PEO-PAGE) with a very narrow molecular weight distribution (Mw/Mn ca. 1.05) were prepared by anionic ring opening polymerization using sodium salt of poly(ethylene oxide) monomethyl ether as macroinitiator and allyl glycidyl ether as functional monomer. The copolymers were covalently modified via reactive double bonds by the addition of methyl sulfanylacetate. The resulting ester subsequently reacted with hydrazine hydrate yielding polymer hydrazide. The hydrazide was coupled with DOX yielding pH-sensitive hydrazone bonds between the drug and carrier. The resulting conjugate containing ca. 3 wt.% DOX forms micelles with Rh(a)=104 nm in phosphate-buffered saline. After incubation in buffers at 37 degrees C DOX was released faster at pH 5.0 (close to pH in endosomes; 43% DOX released within 24 h) than at pH 7.4 (pH of blood plasma; 16% DOX released within 24 h). Cleavage of hydrazone bonds between DOX and carrier continues even after plateau in the DOX release from micelles incubated in aqueous solutions is reached.

  4. Biocatalytic synthesis of polymeric nanowires by micellar templates of ionic surfactants

    Energy Technology Data Exchange (ETDEWEB)

    Nazari, K., E-mail: nazarikh@ripi.ir [Research Institute of Petroleum Industry, NIOC, P.O. Box 14665-137, Tehran (Iran, Islamic Republic of); Chemistry Dept., Shahr Rey Islamic Azad University, P.O. Box 18735-334, Tehran (Iran, Islamic Republic of); Adhami, F.; Najjar-Safari, A.; Salmani, S. [Chemistry Dept., Shahr Rey Islamic Azad University, P.O. Box 18735-334, Tehran (Iran, Islamic Republic of); Mahmoudi, A. [Chemistry Dept., Karaj Islamic Azad University, Karaj (Iran, Islamic Republic of)

    2011-07-15

    Highlights: {yields} Soft-template production of polyguaiacol nanowire was done by peroxidase enzyme. {yields} Main advantage of this simple method is producing soluble encapsulated nanowires. {yields} Nanowire can be easily precipitated and separated by dilution with distilled water. {yields} Size tuned templates of sodium decyl sulfate (d = 2.7 nm) gave nanowires with d = 2-4 nm. {yields} Dried surfactant-coated wires recover freshly on specified and desired applications. -- Abstract: Micelle-templated polyguaiacol nanowires were successfully prepared via polymerization oxidation of guaiacol (o-methoxy phenol) by peroxidase enzyme in the presence of hydrogen peroxide at mild reaction conditions. The dimensions of the prepared nanowires were controlled by tuning the size and shape of the micelle structure via changing and controlling the type, chain length and molar concentrations of the ionic surfactant. The progress of the reaction and estimation of the size of soft micellar templates were followed by UV-Vis spectroscopy and dynamic light scattering (DLS). The resulting micelle encapsulated or purified polyguaiacol nanowires were characterized using transmission electron microscopy (TEM).

  5. Micellar Self-Assembly of Recombinant Resilin-/Elastin-Like Block Copolypeptides.

    Science.gov (United States)

    Weitzhandler, Isaac; Dzuricky, Michael; Hoffmann, Ingo; Garcia Quiroz, Felipe; Gradzielski, Michael; Chilkoti, Ashutosh

    2017-08-14

    Reported here is the synthesis of perfectly sequence defined, monodisperse diblock copolypeptides of hydrophilic elastin-like and hydrophobic resilin-like polypeptide blocks and characterization of their self-assembly as a function of structural parameters by light scattering, cryo-TEM, and small-angle neutron scattering. A subset of these diblock copolypeptides exhibit lower critical solution temperature and upper critical solution temperature phase behavior and self-assemble into spherical or cylindrical micelles. Their morphologies are dictated by their chain length, degree of hydrophilicity, and hydrophilic weight fraction of the ELP block. We find that (1) independent of the length of the corona-forming ELP block there is a minimum threshold in the length of the RLP block below which self-assembly does not occur, but that once that threshold is crossed, (2) the RLP block length is a unique molecular parameter to independently tune self-assembly and (3) increasing the hydrophobicity of the corona-forming ELP drives a transition from spherical to cylindrical morphology. Unlike the self-assembly of purely ELP-based block copolymers, the self-assembly of RLP-ELPs can be understood by simple principles of polymer physics relating hydrophilic weight fraction and polymer-polymer and polymer-solvent interactions to micellar morphology, which is important as it provides a route for the de novo design of desired nanoscale morphologies from first principles.

  6. Environmental monitoring of phenolic pollutants in water by cloud point extraction prior to micellar electrokinetic chromatography.

    Science.gov (United States)

    Stege, Patricia W; Sombra, Lorena L; Messina, Germán A; Martinez, Luis D; Silva, María F

    2009-05-01

    Many aromatic compounds can be found in the environment as a result of anthropogenic activities and some of them are highly toxic. The need to determine low concentrations of pollutants requires analytical methods with high sensitivity, selectivity, and resolution for application to soil, sediment, water, and other environmental samples. Complex sample preparation involving analyte isolation and enrichment is generally necessary before the final analysis. The present paper outlines a novel, simple, low-cost, and environmentally friendly method for the simultaneous determination of p-nitrophenol (PNP), p-aminophenol (PAP), and hydroquinone (HQ) by micellar electrokinetic capillary chromatography after preconcentration by cloud point extraction. Enrichment factors of 180 to 200 were achieved. The limits of detection of the analytes for the preconcentration of 50-ml sample volume were 0.10 microg L(-1) for PNP, 0.20 microg L(-1) for PAP, and 0.16 microg L(-1) for HQ. The optimized procedure was applied to the determination of phenolic pollutants in natural waters from San Luis, Argentina.

  7. Development and validation of micellar liquid chromatographic methods for the determination of antibiotics in different matrixes.

    Science.gov (United States)

    Rambla-Alegre, Maria; Esteve-Romero, Josep; Carda-Broch, Samuel

    2011-01-01

    Antibiotics are the most important bioactive and chemotherapeutic compounds to be produced by microbiological synthesis, and they have proved their worth in a variety of fields, such as medicinal chemistry, agriculture, and the food industry. Interest in antibiotics has grown in parallel with an increasingly high degree of productivity in the field of analytical applications. Therefore, it is necessary to develop chromatographic procedures capable of determining various drugs simultaneously in the shortest possible time. Micellar liquid chromatography (MLC) is an RP-HPLC technique that offers advantages over conventional HPLC as far as sample preparation, selectivity, and versatility are concerned. Its main advantage is that samples can be injected directly into the chromatographic system with no previous preparation step. This paper mainly focuses on the results of the authors' own recent research and reports the chromatographic conditions for determination of various antibiotics (penicillins, quinolones, and sulfonamides) in different matrixes (pharmaceuticals, biological fluids, and food). The work of other authors on MLC-based antibiotic determination has been included.

  8. Analysis of Dyes Extracted from Millimeter-Size Nylon Fibers by Micellar Electrokinetic Chromatography

    International Nuclear Information System (INIS)

    Lewis, L.A.

    2001-01-01

    The Learning Objective is to present to the forensic community a potential qualitative/quantitative method for trace-fiber color comparisons using micellar electrokinetic chromatography (MEKC). Developing a means of analyzing extracted dye constituents from millimeter-size nylon fiber samples was the objective of this research initiative. Aside from ascertaining fiber type, color evaluation and source comparison of trace-fiber evidence plays a critical role in forensic-fiber examinations. Literally thousands of dyes exist to date, including both natural and synthetic compounds. Typically a three-color-dye combination is employed to affect a given color on fiber material. The result of this practice leads to a significant number of potential dye combinations capable of producing a similar color and shade. Since a typical forensic fiber sample is 2 mm or less in length, an ideal forensic dye analysis would qualitatively and quantitatively identify the extracted dye constituents from a sample size of 1 mm or smaller. The goal of this research was to develop an analytical method for comparing individual dye constituents from trace-fiber evidence with dyes extracted from a suspected source, while preserving as much of the original evidence as possible

  9. Capillary sieving electrophoresis and micellar electrokinetic capillary chromatography produce highly correlated separation of tryptic digests

    Science.gov (United States)

    Dickerson, Jane A.; Dovichi, Norman J.

    2011-01-01

    We perform two-dimensional capillary electrophoresis on fluorescently labeled proteins and peptides. Capillary sieving electrophoresis was performed in the first dimension and micellar electrokinetic capillary chromatography was performed in the second. A cellular homogenate was labeled with the fluorogenic reagent FQ and separated using the system. This homogenate generated a pair of ridges; the first had essentially constant migration time in the CSE dimension, while the second had essentially constant migration time in the MEKC dimension. In addition a few spots were scattered through the electropherogram. The same homogenate was digested using trypsin, and then labeled and subjected to the two dimensional separation. In this case, the two ridges observed from the original two-dimensional separation disappeared, and were replaced by a set of spots that fell along the diagonal. Those spots were identified using a local-maximum algorithm and each was fit using a two-dimensional Gaussian surface by an unsupervised nonlinear least squares regression algorithm. The migration times of the tryptic digest components were highly correlated (r = 0.862). When the slowest migrating components were eliminated from the analysis, the correlation coefficient improved to r = 0.956. PMID:20564272

  10. High-density arrays of titania nanoparticles using monolayer micellar films of diblock copolymers as templates.

    Science.gov (United States)

    Li, Xue; Lau, King Hang Aaron; Kim, Dong Ha; Knoll, Wolfgang

    2005-05-24

    Highly dense arrays of titania nanoparticles were fabricated using surface micellar films of poly(styrene-block-2-vinylpyridine) diblock copolymers (PS-b-P2VP) as reaction scaffolds. Titania could be introduced selectively within P2VP nanodomains in PS-b-P2VP films through the binary reaction between water molecules trapped in the P2VP domains and the TiCl(4) vapor precursors. Subsequent UV exposure or oxygen plasma treatment removed the organic matrix, leading to titania nanoparticle arrays on the substrate surface. The diameter of the titania domains and the interparticle distance were defined by the lateral scale present in the microphase-separated morphology of the initial PS-b-P2VP films. The typical diameter of titania nanoparticles obtained by oxygen plasma treatment was of the order of approximately 23 nm. Photoluminescence (PL) properties were investigated for films before and after plasma treatment. Both samples showed PL properties with major physical origin due to self-trapped excitons, indicating that the local environment of the titanium atoms is similar.

  11. Acid-base equilibria and solubility of loratadine and desloratadine in water and micellar media.

    Science.gov (United States)

    Popović, Gordana; Cakar, Mira; Agbaba, Danica

    2009-01-15

    Acid-base equilibria in homogeneous and heterogeneous systems of two antihistaminics, loratadine and desloratadine were studied spectrophotometrically in Britton-Robinson's buffer at 25 degrees C. Acidity constant of loratadine was found to be pK(a) 5.25 and those of desloratadine pK(a1) 4.41 and pK(a2) 9.97. The values of intrinsic solubilities of loratadine and desloratadine were 8.65x10(-6) M and 3.82x10(-4) M, respectively. Based on the pK(a) values and intrinsic solubilities, solubility curves of these two drugs as a function of pH were calculated. The effects of anionic, cationic and non-ionic surfactants applied in the concentration exceeding critical micelle concentration (cmc) on acid-base properties of loratadine and desloratadine, as well as on intrinsic solubility of loratadine were also examined. The results revealed a shift of pK(a) values in micellar media comparing to the values obtained in water. These shifts (DeltapK(a)) ranged from -2.24 to +1.24.

  12. Influence of buffer zone concentrations on efficiency in partial filling micellar electrokinetic chromatography.

    Science.gov (United States)

    Michalke, D; Kolb, S; Welsch, T

    2001-05-04

    The potential of counter pressure-moderated partial filling micellar electrokinetic chromatography (PF-MEKC) was investigated in this work. Plate numbers of homologous omega-phenylalcohols were measured in a two-plug PF-MEKC system varying the concentrations and hence the ionic strengths of the background buffer compared to the sodium dodecyl sulfate-containing separation buffer and the counter pressure on the cathodic buffer reservoir. It was observed that plate numbers are strongly influenced by both the buffer concentrations and the counter pressure. Highest plate numbers were obtained with a buffer system where the concentrations are adjusted such that the electroosmotic flow velocities in both zones are equal. Differences in the local electroosmotic flow velocities of the zones caused by different buffer concentrations are responsible for tremendously reduced plate numbers. The efficiency drop is explained in several models by the formation of an intersegmental pressure which produces a parabolically shaped laminar flow component in both zones. Thus, the electroosmotic plug-like flow profile is distorted and the efficiency is reduced. The effect of counter pressure on efficiency turned out to be very complex in dependence on the buffer system applied.

  13. Kinetics and mechanism of the cutinase-catalyzed transesterification of oils in AOT reversed micellar system.

    Science.gov (United States)

    Badenes, Sara M; Lemos, Francisco; Cabral, Joaquim M S

    2011-11-01

    The kinetics of the enzymatic transesterification between a mixture of triglycerides (oils) and methanol for biodiesel production in a bis(2-ethylhexyl) sodium sulfosuccinate (AOT)/isooctane reversed micellar system, using recombinant cutinase from Fusarium solani pisi as a catalyst, was investigated. In order to describe the results that were obtained, a mechanistic scheme was proposed, based on the literature and on the experimental data. This scheme includes the following reaction steps: the formation of the active enzyme-substrate complex, the addition of an alcohol molecule to the complex followed by the separation of a molecule of the fatty acid alkyl ester and a glycerol moiety, and release of the active enzyme. Enzyme inhibition and deactivation effects due to methanol and glycerol were incorporated in the model. This kinetic model was fitted to the concentration profiles of the fatty acid methyl esters (the components of biodiesel), tri-, di- and monoglycerides, obtained for a 24 h transesterification reaction performed in a stirred batch reactor under different reaction conditions of enzyme and initial substrates concentration.

  14. Origin of shear thickening in semidilute wormlike micellar solutions and evidence of elastic turbulence

    International Nuclear Information System (INIS)

    Marín-Santibáñez, Benjamín M.; Pérez-González, José; Rodríguez-González, Francisco

    2014-01-01

    The origin of shear thickening in an equimolar semidilute wormlike micellar solution of cetylpyridinium chloride and sodium salicylate was investigated in this work by using Couette rheometry, flow visualization, and capillary Rheo-particle image velocimetry. The use of the combined methods allowed the discovery of gradient shear banding flow occurring from a critical shear stress and consisting of two main bands, one isotropic (transparent) of high viscosity and one structured (turbid) of low viscosity. Mechanical rheometry indicated macroscopic shear thinning behavior in the shear banding regime. However, local velocimetry showed that the turbid band increased its viscosity along with the shear stress, even though barely reached the value of the viscosity of the isotropic phase. This shear band is the precursor of shear induced structures that subsequently give rise to the average increase in viscosity or apparent shear thickening of the solution. Further increase in the shear stress promoted the growing of the turbid band across the flow region and led to destabilization of the shear banding flow independently of the type of rheometer used, as well as to vorticity banding in Couette flow. At last, vorticity banding disappeared and the flow developed elastic turbulence with chaotic dynamics

  15. Determination of strobilurin fungicide residues in fruits and vegetables by micellar electrokinetic capillary chromatography with sweeping.

    Science.gov (United States)

    Wang, Kun; Chen, Guan-hua; Wu, Xian; Shi, Jie; Guo, Dong-shan

    2014-02-01

    A new assay of micellar electrokinetic capillary chromatography with sweeping was developed to determine azoxystrobin, kresoxim-methyl and pyraclostrobin in fruits and vegetables. The key factors affecting resolution and peak height were studied and the optimum conditions were obtained for separation and enrichment. The running buffer consisted of 40 mM borate, 25 mM sodium dodecyl sulfate and 15% acetonitrile, and its pH was adjusted to 8.4. The sample was injected for 677 nL and the separation voltage was 25 kV. Under the optimum conditions, the enrichment factors of azoxystrobin, kresoxim-methyl and pyraclostrobin were 861, 550 and 403; the linear dynamic ranges were all 0.01-5.0 mg/L; the limits of detection were 0.002, 0.001 and 0.002 mg/kg; the recoveries of spiked samples were 85.1-98.5%, 87.5-97.0% and 89.1-99.1%, respectively. The assay can meet the requirement of maximum residue limits for these three strobilurin fungicides, and has been applied for determining their residues in fruits and vegetables.

  16. O-(β-hydroxyethylrutosides determination by micellar flow injection (FI-spectrofluorimetry

    Directory of Open Access Journals (Sweden)

    Cecilia Mariana Peralta

    2014-12-01

    Full Text Available A simple, eco-friendly, sensitive and economic flow injection spectrofluorimetric method was developed for the determination of O-(β-hydroxyethylrutosides. The procedure was based on the use of an anionic surfactant such as sodium dodecyl sulfate to provide an appreciable O-(β-hydroxyethylrutosides fluorescence enhancement, increasing considerably the sensitivity of detection. All the variables affecting the fluorescence intensity were studied and optimized. The flow rate was 5 mL/min with detection at 450 nm (after excitation at 346 nm. A linear correlation between drug amount and peak area was established for O-(β-hydroxyethylrutosides in the range of 0.01–200 µg/mL with a detection limit of 0.001 µg/mL (s/n=3. Validation processes were performed by recovering studies with satisfactory results. The new methodology can be employed for the routine analysis of O-(β-hydroxyethylrutosides in bulks as well as in commercial formulations. Keywords: O-(β-hydroxyethylrutosides, Micellar enhancement, Flow injection, Spectrofluorimetry, Pharmaceuticals

  17. Structural and phase transition changes of sodium dodecyl sulfate micellar solution in alcohols probed by small-angle neutron scattering (SANS)

    Energy Technology Data Exchange (ETDEWEB)

    Putra, Edy Giri Rachman [Neutron Scattering Laboratory, National Nuclear Energy Agency of Indonesia (BATAN), Gedung 40 BATAN, Kawasan Puspiptek Serpong, Tangerang 15314 (Indonesia); Patriati, Arum [Neutron Scattering Laboratory, National Nuclear Energy Agency of Indonesia (BATAN), Gedung 40 BATAN, Kawasan Puspiptek Serpong, Tangerang 15314 (Indonesia); Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Gadjah Mada, Bulaksumur, Yogyakarta 55281, Indonesia giri@batan.go.id (Indonesia)

    2015-04-16

    Small-angle neutron scattering (SANS) measurements on 0.3M sodium dodecyl sulfate (SDS) micellar solutions have been performed in the presence of n-alcohols, from ethanol to decanol at different alcohol concentrations, 2–10 wt%. The ellipsoid micellar structure which occurred in the 0.3M SDS in aqueous solution with the size range of 30–50 Å has different behavior at various hydrocarbon chain length and concentration of alcohols. At low concentration and short chain-length of alcohols, such as ethanol, propanol, and butanol, the size of micelles reduced and had a spherical-like structure. The opposite effect occurred as medium to long chain alcohols, such as hexanol, octanol and decanol was added into the 0.3M SDS micellar solutions. The micelles structure changed to be more elongated in major axis and then crossed the critical phase transition from micellar solution into liquid crystal phase as lamellar structure emerged by further addition of alcohols. The inter-lamellar distances were also depending on the hydrocarbon chain length and concentration of alcohols. In the meantime, the persistent micellar structures occurred in addition of medium chain of n-alcohol, pentanol at all concentrations.

  18. Structural and phase transition changes of sodium dodecyl sulfate micellar solution in alcohols probed by small-angle neutron scattering (SANS)

    International Nuclear Information System (INIS)

    Putra, Edy Giri Rachman; Patriati, Arum

    2015-01-01

    Small-angle neutron scattering (SANS) measurements on 0.3M sodium dodecyl sulfate (SDS) micellar solutions have been performed in the presence of n-alcohols, from ethanol to decanol at different alcohol concentrations, 2–10 wt%. The ellipsoid micellar structure which occurred in the 0.3M SDS in aqueous solution with the size range of 30–50 Å has different behavior at various hydrocarbon chain length and concentration of alcohols. At low concentration and short chain-length of alcohols, such as ethanol, propanol, and butanol, the size of micelles reduced and had a spherical-like structure. The opposite effect occurred as medium to long chain alcohols, such as hexanol, octanol and decanol was added into the 0.3M SDS micellar solutions. The micelles structure changed to be more elongated in major axis and then crossed the critical phase transition from micellar solution into liquid crystal phase as lamellar structure emerged by further addition of alcohols. The inter-lamellar distances were also depending on the hydrocarbon chain length and concentration of alcohols. In the meantime, the persistent micellar structures occurred in addition of medium chain of n-alcohol, pentanol at all concentrations

  19. Micellar solubilization in strongly interacting binary surfactant systems. [Binary surfactant systems of: dodecyltrimethylammonium chloride + sodium dodecyl sulfate; benzyldimethyltetradecylammonium chloride + tetradecyltrimethylammonium chloride

    Energy Technology Data Exchange (ETDEWEB)

    Treiner, C. (Universite Pierre et Marie Curie, Paris (France)); Nortz, M.; Vaution, C. (Faculte de Pharmacie de Paris-sud, Chatenay-Malabry (France))

    1990-07-01

    The apparent partition coefficient P of barbituric acids between micelles and water has been determined in mixed binary surfactant solutions from solubility measurements in the whole micellar composition range. The binary systems chosen ranged from the strongly interacting system dodecyltrimethylammonium chloride + sodium dodecyl sulfate to weakly interacting systems such as benzyldimethyltetradecylammonium chloride + tetradecyltrimethyammonium chloride. In all cases studied, mixed micelle formation is unfavorable to micellar solubilization. A correlation is found between the unlike surfactants interaction energy, as measured by the regular solution parameter {beta} and the solute partition coefficient change upon surfactant mixing. By use of literature data on micellar solubilization in binary surfactant solutions, it is shown that the change of P for solutes which are solubilized by surface adsorption is generally governed by the sign and amplitude of the interaction parameter {beta}.

  20. Application of Surfactant Micellar Solutions as Extractants and Mobile Phases for TLC-Determination of Purine Bases and Doping Agents in Biological Liquids

    Directory of Open Access Journals (Sweden)

    Daria Victorovna Yedamenko

    2015-04-01

    Full Text Available Separation of caffeine and its metabolites (theophylline and theobromine and doping agents (spironolactone, propranolol, and ephedrine and determination of caffeine in serum sample and propranolol and ephedrine in urine were studied on normal-phase thin layers (“Sorbfil-UV-254”. Aqueous organic solvents and aqueous micellar surfactant solutions were compared as the mobile phases for separation. The acceptable separation of purine bases and doping agents was achieved by micellar Thin Layer Chromatography and normal-phase Thin Layer Chromatography. Anionic surfactant solution with added 1-propanol was the best eluent as for caffeine, theophylline, and theobromine separation, as for doping agents. The best characteristics of caffeine extraction from serum, and propranolol and ephedrine from urine were achieved when micellar eluent based on non-ionic Tween-80 surfactant was used. DOI: http://dx.doi.org/10.17807/orbital.v7i1.632

  1. Interactions between 9,10-anthraquinone and aromatic amines in homogeneous and micellar media: A laser flash photolysis and magnetic field effect study

    International Nuclear Information System (INIS)

    Chowdhury, Adity; Basu, Samita

    2006-01-01

    The interactions between 9,10-anthraquinone (AQ) and different aromatic amines, N,N-dimethylaniline and 4,4'-bis (dimethylamino) diphenylmethane (DMDPM), have been studied using absorption, steady-state fluorescence, and laser flash photolysis techniques in organic homogeneous and heterogeneous micellar media. In polar organic homogeneous medium, electron transfer (ET) occurs from amines to excited AQ. In micellar medium, similar intermolecular ET is observed. However, in latter medium, ET predominates over hydrogen abstraction from micelles by excited AQ itself. The occurrence of ET has been further supported by the application of an external magnetic field during laser flash photolysis experiments, which modulates the yield of radical ion pairs formed through ET. Another novel feature, which has also been discussed here, is the abnormal behavior of DMDPM in micellar medium pertaining to energy transfer

  2. Effect of ionic strength on the kinetics of ionic and micellar reactions in aqueous solution

    International Nuclear Information System (INIS)

    Dung, M.H.; Kozak, J.J.

    1982-01-01

    The effect of electrostatic forces on the rate of reaction between ions in aqueous solutions of intermediate ionic strength is studied in this paper. We consider the kinetics of reactions involving simple ionic species (1--1 and 2--2 electrolyte systems) as well as kinetic processes mediated by the presence of micellar ions (or other charged organizates). In the regime of ionic strength considered, dielectric saturation of the solvent in the vicinity of the reacting ions must be taken into account and this is done by introducing several models to describe the recovery of the solvent from saturation to its continuum dielectric behavior. To explore the effects of ion size, charge number, and ionic strength on the overall rate constant for the process considered, we couple the traditional theory of ionic reactions in aqueous solution with calculations of the electrostatic potential obtained via solution of the nonlinear Poisson--Boltzmann equation. The great flexibility of the nonlinear Poisson--Boltzmann theory allows us to explore quantitatively the influence of each of these effects, and our simulations show that the short-range properties of the electrostatic potential affect primarily kinetically controlled processes (to varying degrees, depending on the ionic system considered) whereas the down-range properties of the potential play a (somewhat) greater role in influencing diffusion-controlled processes. A detailed examination is made of ionic strength effects over a broad range of ionic concentrations. In the regime of low ionic strength, the limiting slope and intercept of the curve describing the dependence of log k/sub D/ on I/sup 1/2//(1+I/sup 1/2/) may differ considerably from the usual Debye--Hueckel limiting relations, depending on the particular model chosen to describe local saturation effects

  3. Development of Micellar HPLC-UV Method for Determination of Pharmaceuticals in Water Samples

    Directory of Open Access Journals (Sweden)

    Danielle Cristina da Silva

    2018-01-01

    Full Text Available Method for extraction and determination of amoxicillin, caffeine, ciprofloxacin, norfloxacin, tetracycline, diclofenac, ibuprofen, nimesulide, levonorgestrel, and 17α-ethynylestradiol exploiting micellar liquid chromatography with PDA detector and solid-phase extraction was proposed. The usage of toxic solvents was low; the chromatographic separation of the medicaments was performed using a C18 column and mobile phases A and B containing 15.0% (v/v ethanol, 3.0% (m/v sodium dodecyl sulfate (SDS, and 0.02 mol·L−1 phosphate at pHs 7.0 and 8.0, respectively. The method is simple, selective, and fast, and the analytes were separated in 23.0 min. For extraction, 1000 mL of sample containing 2.0% (v/v ethanol and 0.002 mol·L−1 citric acid at pH 2.50 was loaded through a 1000 mg of C18 cartridge. The analytes were eluted using 3.0 mL of ethanol, which were evaporated and redissolved in 0.5 mL of mobile phase. Concentration factors better than 1200, except amoxicillin (224, were obtained. The analytical curves were linear (R2 better than 0.992; LOD and LOQ n=10 presented values in the range of 0.019–0.247 and 0.058–0.752 mg·L−1, respectively. Recoveries of 99% were obtained, and the results are in agreement with those obtained by the comparative methods.

  4. Thermodynamic models to elucidate the enantioseparation of drugs with two stereogenic centers by micellar electrokinetic chromatography.

    Science.gov (United States)

    Guo, Xuming; Liu, Qiuxia; Hu, Shaoqiang; Guo, Wenbo; Yang, Zhuo; Zhang, Yonghua

    2017-08-25

    An equilibrium model depicting the simultaneous protonation of chiral drugs and partitioning of protonated ions and neutral molecules into chiral micelles in micellar electrokinetic chromatography (MEKC) has been introduced. It was used for the prediction and elucidation of complex changes in migration order patterns with experimental conditions in the enantioseparation of drugs with two stereogenic centers. Palonosetron hydrochloride (PALO), a weakly basic drug with two stereogenic centers, was selected as a model drug. Its four stereoisomers were separated by MEKC using sodium cholate (SC) as chiral selector and surfactant. Based on the equilibrium model, equations were derived for a calculation of the effective mobility and migration time of each stereoisomer at a certain pH. The migration times of four stereoisomers at different pHs were calculated and then the migration order patterns were constructed with derived equations. The results were in accord with the experiment. And the contribution of each mechanism to the separation and its influence on the migration order pattern was analyzed separately by introducing virtual isomers, i.e., hypothetical stereoisomers with only one parameter changed relative to a real PALO stereoisomer. A thermodynamic model for a judgment of the correlation of interactions between two stereogenic centers of stereoisomers and chiral selector was also proposed. According to this model, the interactions of two stereogenic centers of PALO stereoisomers in both neutral molecules and protonated ions with chiral selector are not independent, so the chiral recognition in each pair of enantiomers as well as the recognition for diastereomers is not simply the algebraic sum of the contributions of two stereogenic centers due to their correlation. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Micellar dipolar rearrangement is sensitive to hydrophobic chain length: Implication for structural switchover of piroxicam.

    Science.gov (United States)

    Sethy, Dasaratha; Chakraborty, Hirak

    2016-10-01

    The interfacial properties of the membrane are exceptionally vital in drug-membrane interaction. They not only select out a particular prototropic form of the drug molecule for incorporation, but are also potent enough to induce structural switchover of these drugs in several cases. In this work, we quantitatively monitored the change in dipolar rearrangement of the micellar interface (as a simplified membrane mimic) by measuring the dielectric constant and dipole potential with the micellization of SDS at pH 3.6. The dielectric constant and dipole potential were measured utilizing the fluorescence of polarity sensitive probe, pyrene and potential-sensitive probe, di-8-ANEPPS, respectively. Our study demonstrates that the change in dipolar rearrangement directly influences the switchover equilibrium between the anionic and neutral from of piroxicam. We have further extended our work to evaluate the effect of hydrophobic chain length of the surfactants on the dipolar rearrangement and its effect on the structural switchover of piroxicam. It is interesting that the extent of switchover of piroxicam is directly correlated with the dipolar rearrangement induced bythe varying hydrophobic chain length of the surfactants. To the best of our knowledge, our results constitute the first report to show the dependence of dipole potential on the hydrophobic chain length of the surfactant and demonstrate that the dipolar rearrangement directly tunes the extent of structural switchover of piroxicam, which was so far only intuitive. We consider that this new finding would have promising implication in drug distribution and drug efficacy. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  6. Synthesis and antibacterial activity of water-dispersible silver nanoparticles via micellar nanoreactors

    Science.gov (United States)

    Pofali, Prasad; Shirolikar, Seema; Borde, Lalit; Pattani, Aditya; Dandekar, Prajakta; Jain, Ratnesh

    2018-04-01

    We have synthesized silver nanoparticles (AgNPs) using micelles of sugar fatty acid ester by dissolving the surfactant in a mixture of iso-octane and n-butanol, with solid-liquid extraction. Highly concentrated, water-dispersible AgNPs were obtained after thorough washing with alcohol, to remove excess of sucrose fatty acid ester DK SS and salt, followed by drying. The particles were characterized for their size, morphology and crystallinity using UV-Visible spectrophotometry, Transmission Electron Microscopy and x-ray diffractometry. Antibacterial study, confirmed the activity of nanoparticles against E. coli, P. aeruginosa and S. aureus, which causes diseases including diarrhoea and several life-threatening infections. Antibacterial activity of E. coli and P. aeruginosa was found to be 2.5 fold and for S. aureus 1.6 fold compared to 50 ppm conc. of Silver Nitrate. Our method of producing nanoparticles is employed as a platform technology for synthesizing other inorganic nanoparticles. This is the first report discussing the use of micellar carriers for obtaining silver nanopowder, to the best of our knowledge, which has the potential to overcome limitations during fabrication of AgNPs using reverse/inverse micelles. Our method yielded nano-sized, water-dispersible AgNPs via an easy and economic approach. The one-pot approach possesses advantages in terms of cost and simplicity, as compared with traditional methods of producing powdered AgNPs using energy intensive and expensive techniques like lyophilisation. The developed method, thus, possesses immense potential for commercial synthesis of AgNPs.

  7. Flow-injection fluorimetric determination of menadione using on-line photo-reduction in micellar media

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Ruiz, Tomas; Martinez-Lozano, Carmen; Tomas, Virginia; Martin, Jesus

    2004-07-01

    A very sensitive fluorimetric method for the determination of menadione using a flow injection system is proposed. The method is based on the on-line reduction of menadione in dodecylsulphate micelles upon irradiation with UV light. The strong fluorescence of the reduced menadione in micellar medium is measured at 410 nm with excitation at 340 nm. The method shows a linear range between 2.42 and 245 ng ml{sup -1} and a limit of detection of 0.18 ng ml{sup -1}. The sample throughput was 90 injections per hour. The applicability of the assay was demonstrated by analysing this vitamin in commercial pharmaceutical preparations.

  8. Flow-injection fluorimetric determination of menadione using on-line photo-reduction in micellar media

    International Nuclear Information System (INIS)

    Perez-Ruiz, Tomas; Martinez-Lozano, Carmen; Tomas, Virginia; Martin, Jesus

    2004-01-01

    A very sensitive fluorimetric method for the determination of menadione using a flow injection system is proposed. The method is based on the on-line reduction of menadione in dodecylsulphate micelles upon irradiation with UV light. The strong fluorescence of the reduced menadione in micellar medium is measured at 410 nm with excitation at 340 nm. The method shows a linear range between 2.42 and 245 ng ml -1 and a limit of detection of 0.18 ng ml -1 . The sample throughput was 90 injections per hour. The applicability of the assay was demonstrated by analysing this vitamin in commercial pharmaceutical preparations

  9. Fluorescence resonance energy transfer between perylene and riboflavin in micellar solution and analytical application on determination of vitamin B2

    International Nuclear Information System (INIS)

    Bhattar, S.L.; Kolekar, G.B.; Patil, S.R.

    2008-01-01

    Fluorescence resonance energy transfer (FRET) between perylene and riboflavin is studied in micellar solution of sodium dodecyl sulfate. The fluorescence of perylene is quenched by riboflavin and quenching is in accordance with Stern-Volmer relation. The efficiency of energy transfer is found to depend on the concentration of riboflavin. The value of critical energy transfer distance (R 0 ) calculated by using Foster relation is 32.13 A, and as it is less than 50 A, it indicates efficient energy transfer in the present system. The analytical relation was established between extent of sensitization and concentration of riboflavin, which helped to estimate vitamin B 2 directly from pharmaceutical tablets

  10. Diffusion and localization of o-Ps in Dsub(2)O determined from positron annihilation in SDS micellar solutions

    International Nuclear Information System (INIS)

    Vass, Sz.; Kajcsos, Zs.; Molnar, B.

    1985-04-01

    A microscopic diffusion model is presented for the determination of orthopositronium (o-Ps) lifetime in micellar solutions. Among other parameters, the lifetime density function depends on the o-Ps diffusion coefficient in the water phase. Orthopositronium diffusion coefficients are determined by fitting this lifetime density function to positron annihilation spectra obtained from 1 mol/dmsup(3) solution of sodium dodecylsulphate (SDS) in Dsub(2)O at different temperatures. The activation energy of the o-Ps diffusion in Dsub(2)O obtained from the Arrhenius-plot as Esub(a)=(0.9sub(22)+-0.1sub(03)) eV indicates strong localization. (author)

  11. A novel, rapid and automated conductometric method to evaluate surfactant-cells interactions by means of critical micellar concentration analysis.

    Science.gov (United States)

    Tiecco, Matteo; Corte, Laura; Roscini, Luca; Colabella, Claudia; Germani, Raimondo; Cardinali, Gianluigi

    2014-07-25

    Conductometry is widely used to determine critical micellar concentration and micellar aggregates surface properties of amphiphiles. Current conductivity experiments of surfactant solutions are typically carried out by manual pipetting, yielding some tens reading points within a couple of hours. In order to study the properties of surfactant-cells interactions, each amphiphile must be tested in different conditions against several types of cells. This calls for complex experimental designs making the application of current methods seriously time consuming, especially because long experiments risk to determine alterations of cells, independently of the surfactant action. In this paper we present a novel, accurate and rapid automated procedure to obtain conductometric curves with several hundreds reading points within tens of minutes. The method was validated with surfactant solutions alone and in combination with Saccharomyces cerevisiae cells. An easy-to use R script, calculates conductometric parameters and their statistical significance with a graphic interface to visualize data and results. The validations showed that indeed the procedure works in the same manner with surfactant alone or in combination with cells, yielding around 1000 reading points within 20 min and with high accuracy, as determined by the regression analysis. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  12. Prediction of retention in micellar electrokinetic chromatography based on molecular structural descriptors by using the heuristic method

    International Nuclear Information System (INIS)

    Liu Huanxiang; Yao Xiaojun; Liu Mancang; Hu Zhide; Fan Botao

    2006-01-01

    Based on calculated molecular descriptors from the solutes' structure alone, the micelle-water partition coefficients of 103 solutes in micellar electrokinetic chromatography (MEKC) were predicted using the heuristic method (HM). At the same time, in order to show the influence of different molecular descriptors on the micelle-water partition of solute and to well understand the retention mechanism in MEKC, HM was used to build several multivariable linear models using different numbers of molecular descriptors. The best 6-parameter model gave the following results: the square of correlation coefficient R 2 was 0.958 and the mean relative error was 3.98%, which proved that the predictive values were in good agreement with the experimental results. From the built model, it can be concluded that the hydrophobic, H-bond, polar interactions of solutes with the micellar and aqueous phases are the main factors that determine their partitioning behavior. In addition, this paper provided a simple, fast and effective method for predicting the retention of the solutes in MEKC from their structures and gave some insight into structural features related to the retention of the solutes

  13. Separation of mercury(II), methylmercury and phenylmercury by micellar high-performance liquid chromatography on short columns

    International Nuclear Information System (INIS)

    Hutta, M.; Megova, S.; Halko, R.

    1998-01-01

    Three environmentally and agrochemically important mercury species: methylmercury, phenylmercury and mercury(II) are separated within 4 minutes as bromocomplexes by micellar liquid chromatography using very short reversed-phase (RP) C18 columns (up to 30 mm). The micellar mobile phase containing 0.05M cetyltrimethylammonium bromide (CTMA + Br - ), 1% (v/v) 2-propanol, 0.001M cyclohexylenediaminetetraacetic acid (DCTA) and sulfuric acid (pH 2) showed good selectivity in mixed reversed-phase and anion-exchange mode. The above mentioned separation order in which organomercurials are eluted far behind the void volume of the column, but before the mercury(II) peak is advantageous in all instances where mercury(II) is present in real samples in great excess. Environmental and agrochemical samples contain humic material which does not interfere in this particular system. The low cost photometric detection at 500 nm after post-column derivatization by CTMA + Br - micellized dithizone is almost free from interferences and enables detection limits at the 1-3 ng level (e.g., 0.1 ppm Hg) for 20 μl samples. (author)

  14. Simultaneous Extraction, Enrichment and Removal of Dyes from Aqueous Solutions Using a Magnetic Aqueous Micellar Two-Phase System

    Directory of Open Access Journals (Sweden)

    Shuanggen Wu

    2017-12-01

    Full Text Available The magnetic aqueous micellar two-phase system (MAMTPS has the advantages combined of magnetic solid phase extraction (MSPE and aqueous micellar two-phase system (AMTPS. Thus, MAMTPS based on Fe3O4 magnetic nanoparticles (MNPs and a nonionic surfactant Triton X-114 (TX-114 was developed for the extraction, enrichment and removal of three dyes (Congo red, methyl blue, and methyl violet from aqueous solutions in this study. The MNPs Fe3O4@NH2 was screened as the optimal MNPs benefiting the extraction. Then, the influencing factors of MNPs amount, TX-114 concentration, vibration time, and extraction temperature were investigated in detail. The results showed that the extraction efficiencies of three dyes almost reached 100% using MAMTPS under the optimal conditions; MAMTPS had higher extraction ability than the individual MSPE or AMTPS. Thus, MAMTPS had the advantages of simple operation, high extraction ability, easy recycling of MNPs, and short phase-separation time, which showspotential for use in the extraction and analysis of contaminants from water samples.

  15. Determination of adulteration of malachite green in green pea and some prepared foodstuffs by micellar liquid chromatography.

    Science.gov (United States)

    Ashok, Vipin; Agrawal, Nitasha; Durgbanshi, Abhilasha; Esteve-Romero, Josep; Bose, Devasish

    2014-01-01

    A simple, fast, and robust micellar LC method was developed for the separation and identification of the nonpermitted color malachite green in green pea and some ready-to-eat foodstuffs. Malachite green (4-[(4-dimethylaminophenyl) phenyl-methyl]-N,N-dimethylaniline) is a hazardous dye that is used to treat fungal and protozoan infections in fish and is a common adulterant (coloring agent) in green pea and other green vegetables because of its green color. In the present work, malachite green was determined in various foodstuffs using a direct injection technique on an RP C18 column with isocratic elution. The optimum mobile phase consisted of 0.15 M sodium dodecyl sulfate (SDS), 6% pentanol buffered at pH 5. Detection was carried out at 620 nm. Malachite green was eluted in 9.2 min without any interference caused by endogenous compounds. Linearities (r > 0.9999), intraday and interday precision (RSD less than 1.00%) in micellar media, and robustness were studied for method validation. LOD and LOQ were 0.10 and 0.25 ppm, respectively. The simplicity of the developed method makes it useful for routine analysis in the area of food QC.

  16. Micellar effect on the kinetics of oxidation of methyl blue by Ce(IV in sulfuric acid medium

    Directory of Open Access Journals (Sweden)

    Mohammed Hassan

    2015-01-01

    Full Text Available The kinetics of oxidation of methyl blue (MB by Ce(IV in aqueous and surfactant media has been carried out to explore the micellar effect on the rate and kinetic parameters of the reaction. The reaction was found to be first order with respect to both oxidant and substrate and fractional order with respect to H+. The active kinetic species of the oxidant was found to be Ce(SO4+2 based on the effect of ionic strength and sulfate ion on the rate of the reaction. The presence of micelles was found to inhibit the reaction and this effect has been explained by the association of one of the reactants with the micelles leaving the other reactant in the bulk solution. The binding constant and first order rate constant in micellar medium has been obtained by the application of pseudo-phase model to the experimental data. Interestingly, the temperature dependence of the reaction reveals that the reaction has negative activation energy in the absence of micelles, which turns to a positive value in the presence of micelles.

  17. The fabrication of highly ordered block copolymer micellar arrays: control of the separation distances of silicon oxide dots

    Science.gov (United States)

    Yoo, Hana; Park, Soojin

    2010-06-01

    We demonstrate the fabrication of highly ordered silicon oxide dotted arrays prepared from polydimethylsiloxane (PDMS) filled nanoporous block copolymer (BCP) films and the preparation of nanoporous, flexible Teflon or polyimide films. Polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) films were annealed in toluene vapor to enhance the lateral order of micellar arrays and were subsequently immersed in alcohol to produce nano-sized pores, which can be used as templates for filling a thin layer of PDMS. When a thin layer of PDMS was spin-coated onto nanoporous BCP films and thermally annealed at a certain temperature, the PDMS was drawn into the pores by capillary action. PDMS filled BCP templates were exposed to oxygen plasma environments in order to fabricate silicon oxide dotted arrays. By addition of PS homopolymer to PS-b-P2VP copolymer, the separation distances of micellar arrays were tuned. As-prepared silicon oxide dotted arrays were used as a hard master for fabricating nanoporous Teflon or polyimide films by spin-coating polymer precursor solutions onto silicon patterns and peeling off. This simple process enables us to fabricate highly ordered nanoporous BCP templates, silicon oxide dots, and flexible nanoporous polymer patterns with feature size of sub-20 nm over 5 cm × 5 cm.

  18. The fabrication of highly ordered block copolymer micellar arrays: control of the separation distances of silicon oxide dots

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Hana; Park, Soojin, E-mail: spark@unist.ac.kr [Interdisciplinary School of Green Energy, Ulsan National Institute of Science and Technology, Banyeon-ri 100, Ulsan 689-798 (Korea, Republic of)

    2010-06-18

    We demonstrate the fabrication of highly ordered silicon oxide dotted arrays prepared from polydimethylsiloxane (PDMS) filled nanoporous block copolymer (BCP) films and the preparation of nanoporous, flexible Teflon or polyimide films. Polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) films were annealed in toluene vapor to enhance the lateral order of micellar arrays and were subsequently immersed in alcohol to produce nano-sized pores, which can be used as templates for filling a thin layer of PDMS. When a thin layer of PDMS was spin-coated onto nanoporous BCP films and thermally annealed at a certain temperature, the PDMS was drawn into the pores by capillary action. PDMS filled BCP templates were exposed to oxygen plasma environments in order to fabricate silicon oxide dotted arrays. By addition of PS homopolymer to PS-b-P2VP copolymer, the separation distances of micellar arrays were tuned. As-prepared silicon oxide dotted arrays were used as a hard master for fabricating nanoporous Teflon or polyimide films by spin-coating polymer precursor solutions onto silicon patterns and peeling off. This simple process enables us to fabricate highly ordered nanoporous BCP templates, silicon oxide dots, and flexible nanoporous polymer patterns with feature size of sub-20 nm over 5 cm x 5 cm.

  19. Simultaneous Determination of Tizanidine, Nimesulide, Aceclofenac and Paracetamol in Tablets and Biological Fluids Using Micellar Liquid Chromatography.

    Science.gov (United States)

    Belal, Fathalla; Omar, Mahmoud A; Derayea, Sayed; Hammad, Mohamed A; Zayed, Sahar; Saleh, Safaa F

    2018-03-01

    A simple, sensitive and rapid micellar liquid chromatographic method was developed and validated for simultaneous determination of four drugs, namely, paracetamol (PAR), tizanidine (TZD), aceclofenac (ACF) and nimesulide (NMD). Good chromatographic separation was achieved using Cyano column and micellar mobile phase consisting of 120 mM sodium dodecyl sulfate, 25 mM phosphate buffer and 10% (V/V) butanol. The pH was adjusted to three using phosphoric acid. The total retention time was below 10 min. The analysis was performed at a flow rate of 1 mL/min and a column temperature of 40°C with direct UV detection at 230 nm. Diclofenac sodium was used as the internal standard. The proposed method was validated according to the ICH guidelines and was successfully applied to the analysis of these drugs in their tablet dosage forms with high accuracy. Limits of detection were found to be 0.03, 0.07, 0.033 and 0.11 μg/mL for PAR, ACF, TZD and NMD, respectively. The high sensitivity of developed method permitted its application to the in-vitro determination of the cited drugs in spiked human plasma and urine samples, and the obtained results were satisfactory. However, PAR could not be determined in spiked human urine because its peak overlapped with that of the urine peak.

  20. Effect of micellar environment on Marcus correlation curves for photoinduced bimolecular electron transfer reactions

    Science.gov (United States)

    Kumbhakar, Manoj; Nath, Sukhendu; Mukherjee, Tulsi; Pal, Haridas

    2005-07-01

    Photoinduced electron transfer (ET) between coumarin dyes and aromatic amine has been investigated in two cationic micelles, namely, cetyltrimethyl ammonium bromide (CTAB) and dodecyltrimethyl ammonium bromide (DTAB), and the results have been compared with those observed earlier in sodium dodecyl sulphate (SDS) and triton-X-100 (TX-100) micelles for similar donor-acceptor pairs. Due to a reasonably high effective concentration of the amines in the micellar Stern layer, the steady-state fluorescence results show significant static quenching. In the time-resolved (TR) measurements with subnanosecond time resolution, contribution from static quenching is avoided. Correlations of the dynamic quenching constants (kqTR), as estimated from the TR measurements, show the typical bell-shaped curves with the free-energy changes (ΔG0) of the ET reactions, as predicted by the Marcus outersphere ET theory. Comparing present results with those obtained earlier for similar coumarin-amine systems in SDS and TX-100 micelles, it is seen that the inversion in the present micelles occurs at an exergonicity (-ΔG0>˜1.2-1.3eV) much higher than that observed in SDS and TX-100 micelles (-ΔG0>˜0.7eV), which has been rationalized based on the relative propensities of the ET and solvation rates in different micelles. In CTAB and DTAB micelles, the kqTR values are lower than the solvation rates, which result in the full contribution of the solvent reorganization energy (λs) towards the activation barrier for the ET reaction. Contrary to this, in SDS and TX-100 micelles, kqTR values are either higher or comparable with the solvation rates, causing only a partial contribution of λs in these cases. Thus, Marcus inversion in present cationic micelles is inferred to be the true inversion, whereas that in the anionic SDS and neutral TX-100 micelles are understood to be the apparent inversion, as envisaged from two-dimensional ET theory.

  1. Structural study of the AOT reverse micellar system. Influence of attractive interactions induced by the solubilisation of native and modified proteins

    International Nuclear Information System (INIS)

    Cassin, Guillaume

    1994-01-01

    This research thesis reports the study of the influence of intra-micellar attractions on the thermodynamic behaviour of reverse micellar systems, as well as of the effects induced by the solubilisation of natives or modified proteins. The author proposes a model to explain the decrease of attractions between droplets when the volume fraction occupied by reverse micelles increases. This model which highlights the importance of depletion forces between reverse micelles, allows the building up of a theoretical relationship between the bonding parameter and the volume fraction of reverse micelles. In order to understand the appearance of an attractive term related to the solubilisation of native cytochrome-c in these systems, this protein has been chemically modified. The author highlights the role of the charge born by a micellar probe on the thermodynamic behaviour of micro-emulsions. Then, the author applies the model of dimerizing adhesive spheres to reverse micellar systems containing native cytochrome-c. He shows that theoretical predictions of this model are in agreement with obtained experimental results [fr

  2. SALT-INDUCED TRANSITION FROM A MICELLAR TO A LAMELLAR LIQUID-CRYSTALLINE PHASE IN DILUTE MIXTURES OF ANIONIC AND NONIONIC SURFACTANTS IN AQUEOUS-SOLUTION

    NARCIS (Netherlands)

    SEIN, A; ENGBERTS, JBFN; VANDERLINDEN, E; VANDEPAS, JC

    In dilute mixtures of anionic surfactant, sodium dodecylbenzenesulfonate (NaDoBS), and nonionic poly(ethylene oxide) alkyl monoether (C13-15E(7)) a transition from a micellar to a lamellar phase is found at high salting-out electrolyte (NaCit) concentrations. With an increase of the salt

  3. Computer Color Matching and Levelness of PEG-Based Reverse Micellar Decamethyl cyclopentasiloxane (D5 Solvent-Assisted Reactive Dyeing on Cotton Fiber

    Directory of Open Access Journals (Sweden)

    Alan Y. L. Tang

    2017-07-01

    Full Text Available The color matching and levelness of cotton fabrics dyed with reactive dye, in a non-aqueous environmentally-friendly medium of decamethylcyclopentasiloxane (D5, was investigated using the non-ionic surfactant reverse-micellar approach comprised of poly(ethylene glycol-based surfactant. The calibration dyeing databases for both conventional water-based dyeing and D5-assisted reverse micellar dyeing were established, along with the dyeing of standard samples with predetermined concentrations. Computer color matching (CCM was conducted by using different color difference formulae for both dyeing methods. Experimental results reveal that the measured concentrations were nearly the same as the expected concentrations for both methods. This indicates that the D5-assisted non-ionic reverse micellar dyeing approach can achieve color matching as good as the conventional dyeing system. The levelness of the dyed samples was measured according to the relative unlevelness indices (RUI, and the results reveal that the samples dyed by the D5 reverse micellar dyeing system can achieve good to excellent levelness comparable to that of the conventional dyeing system.

  4. Protolytic properties and complexation of DL-alpha-alanine and DL-alpha-valine and their dipeptides in aqueous and micellar solutions of surfactants

    NARCIS (Netherlands)

    Chernyshova, O. S.; Boychenko, Oleksandr; Abdulrahman, H.; Loginova, L. P.

    In this work we investigated the effect of the micellar media of anionic (sodium dodecylsulfate, SDS), cationic (cetylpiridinium chloride, CPC) and non-ionic (Brij-35) surfactants on the protolytic properties of amino acids DL-alpha-alanine, DL-alpha-valine and dipeptides

  5. Thermodynamics of Micellar Systems : Comparison of Mass Action and Phase Equilibrium Models for the Calculation of Standard Gibbs Energies of Micelle Formation

    NARCIS (Netherlands)

    Blandamer, Michael J.; Cullis, Paul M.; Soldi, L. Giorgio; Engberts, Jan B.F.N.; Kacperska, Anna; Os, Nico M. van

    1995-01-01

    Micellar colloids are distinguished from other colloids by their association-dissociation equilibrium in solution between monomers, counter-ions and micelles. According to classical thermodynamics, the standard Gibbs energy of formation of micelles at fixed temperature and pressure can be related to

  6. Effect of the hydrophilic block length on the surface-active and micellar thermodynamic properties of oxyethylene-oxybutylene diblock copolymers in aqueous solution

    International Nuclear Information System (INIS)

    Khan, A.; Usman, M.; Siddiq, M.; Fatima, G.; Harrison, W.

    2009-01-01

    The effect of hydrophilic block length on the surface and micellar thermodynamic properties of aqueous solution of E/sub 40/B/sub 8/, E/sub 80/B/sub 8/ and E/sub 120/B/sub 8/ diblock copolymers, were studied by surface tension measurements over a wide concentration and temperature range; where E stands for an oxyethylene unit and B for an oxybutylene unit. Like conventional surfactants, two breaks (change in the slope) were observed in the surface tension vs logarithm of concentration curve for all the three copolymers. Surface tension measurements were used to estimate surface excess concentrations (r m), area per molecule at air/water interface a and thermodynamic parameters for all adsorption of the pre-micellar region in the temperature range 20 to 50 degree C. Likewise the critical micelle concentration, CMC and thermodynamic parameters for micellization were also calculated for the post-micellar solutions at all temperatures. For comparison the thermodynamic parameters of adsorption and micellization are discussed in detail. The impact of varying E-block length and temperature on all calculated parameters are also discussed. This study shows the importance of hydrophobic-hydrophilic-balance (HHB) of copolymers on various surface and micellar properties. (author)

  7. Chemiluminescence from an oxidation reaction of rhodamine B with cerium(IV) in a reversed micellar medium of cetyltrimethylammonium chloride in 1-hexanol-cyclohexane/water.

    Science.gov (United States)

    Hasanin, Tamer H A; Tsunemine, Yusuke; Tsukahara, Satoshi; Okamoto, Yasuaki; Fujiwara, Terufumi

    2011-01-01

    The chemiluminescence (CL) emission, observed when rhodamine B (RB) in 1-hexanol-cyclohexane was mixed with cerium(IV) sulfate in sulfuric acid dispersed in a reversed micellar medium of cetyltrimethylammonium chloride (CTAC) in 1-hexanol-cyclohexane/water, was investigated using a flow-injection system. The CL emission from the oxidation reaction of RB with Ce(IV) was found to be stronger in the CTAC reversed micellar solution compared with an aqueous solution. Bearing on the enhancement effect of the CTAC reverse micelles on the RB-Ce(IV) CL, several studies including stopped-flow, fluorescence and electron spin resonance (ESR) spectrometries were performed. Rapid spectral changes of an intermediate in the RB-Ce(IV) reaction in the aqueous and reversed micellar solutions were successfully observed using a stopped-flow method. The effect of the experimental variables, i.e., oxidant concentration, sulfuric acid concentration, the mole fraction of 1-hexanol, water-to-surfactant molar concentration ratio, flow rate, upon the CL intensity was evaluated. Under the experimental conditions optimized for a flow-injection determination of RB based on the new reversed micellar-mediated CL reaction with Ce(IV), a detection limit of 0.08 µmol dm(-3) RB was achieved, and a linear calibration graph was obtained with a dynamic range from 0.5 to 20 µmol dm(-3). The relative standard deviation (n = 6) obtained at an RB concentration of 3 µmol dm(-3) was 3%.

  8. Solvation dynamics in triton-X-100 and triton-X-165 micelles: Effect of micellar size and hydration

    Science.gov (United States)

    Kumbhakar, Manoj; Nath, Sukhendu; Mukherjee, Tulsi; Pal, Haridas

    2004-09-01

    Dynamic Stokes' shift measurements using coumarin 153 as the fluorescence probe have been carried out to study solvation dynamics in two nonionic micelles, viz., triton-X-100 (TX-100) and triton-X-165 (TX-165). In both the micelles, the solvent relaxation dynamics is biexponential in nature. While the fast solvation time τs1 is seen to be almost similar for both the micelles, the slow solvation time τs2 is found to be appreciably smaller in TX-165 than in TX-100 micelle. Dynamic light scattering measurements indicate that the TX-165 micelles are substantially smaller in size than that of TX-100. Assuming similar core size for both the micelles, as expected from the similar chemical structures of the nonpolar ends for both the surfactants, the Palisade layer is also indicated to be substantially thinner for TX-165 micelles than that of TX-100. The aggregation number of TX-165 micelles is also found to be substantially smaller than that of TX-100 micelles. Fluorescence spectral studies of C153 dye in the two micelles indicate that the Palisade layer of TX-165 micelles is more polar than that of TX-100 micelles. Fluorescence anisotropy measurements indicate that the microviscosity in the Palisade layer of TX-165 micelles is also lower than that of TX-100 micelles. Based on these results it is inferred that the structure of the Palisade layer of TX-165 micelles is quite loose and have higher degree hydration in comparison to that of TX-100 micelles. Due to these structural differences in the Palisade layers of TX-165 and TX-100 micelles the solvation dynamics is faster in the former micelles than in the latter. It has been further inferred that in the present systems the collective response of the water molecules at somewhat away from the probes is responsible for the faster component of the solvation time, which does not reflect much of the structural changes of the micellar Palisade layer. On the contrary, the slower solvation time component, which is mainly due to

  9. One-electron redox potentials and rate of electron transfer in aqueous micellar solution. Partially solubilized quinones

    International Nuclear Information System (INIS)

    Almgren, M.; Grieser, F.; Thomas, J.K.

    1979-01-01

    The electron transfer equilibrium between AQS/AQS - and DQ/DQ - (where AQS is sodium 9,10-arthraquinone-2-sulfonate and DQ, duroquinone) has been studied by pulse radiolysis in aqueous micellar solutions of sodium lauryl sulfate. The equilibrium constant is changed as would be expected if AQS, AQS - , and DQ- were all mainly in the aqueous solution, and DQ distributed between the micelles and the aqueous phase with a distribution constant of K/sub D//N = 150 M -1 , in agreement with the independently determined value of this constant. The kinetics of the equilibration show, however, that electron transfer at the micelle surface is important, indicating that also AQS and DQ - are associated with the micelle to some extent. With reasonable assumptions regarding the distribution constants of these species (that have some independent support), the observed catalytic effect of the micelles on the electron transfer from DQ - to AQS can be understood

  10. The effect of caffeine on the reactions of the excited singlet state of pyrene in micellar sodium lauryl sulfate

    Science.gov (United States)

    Hashimoto, Shuichi; Thomas, J. Kerry

    1984-08-01

    The effect of caffeine on a few photo-induced reactions of pyrene in micellar sodium lauryl sulfate (NaLS) has been studied. In these systems caffeine complexes with the pyrene (K asso = 85 ± 10 M -1 and also with the other reactants, e.g. Cu 2+ or TI +. The efficiencies of reactions which involve contact, i.e. pyrene excimer formation, and quenching by TI + ions to give the triplet state of pyrene, are significantly reduced in the presence of caffeine, due to geometric inhibitions formed by the complexation processes. The kinetics of photo-induced electron transfer, e.g. between excited pyrene and Cu 2+, are not affected. However, the subsequent reactions of the products are modified and the yield of ionic products is markedly increased.

  11. Quantitative correlation between counterion (X binding affinity to cationic micelles and X – Induced micellar growth for substituted iodobenzoates (X

    Directory of Open Access Journals (Sweden)

    Nor Saadah M. Yusof

    2017-05-01

    Full Text Available A new semi-empirical kinetic (SEK method has been used to calculate the values of KXBr or RXBr (X represents substituted iodobenzoates, with KX and KBr representing CTABr micellar binding constants of counterions X− (in the presence of either spherical or non-spherical micelles and Br− (in the presence of only spherical micelles, respectively. Steady-shear rheological properties of mixed 0.015 M CTABr/[MX] aqueous solutions reveal the presence of flexible wormlike micelles where MX represents sodium 3- and 4-iodobenzoates. The maxima of the plots of viscosity vs. [MX] at 0.015 M CTABr for MX representing sodium 3- and 4-iodobenzoates support the presence of long linear and entangled wormlike micelles.

  12. On the predictions and limitations of the Becker–Döring model for reaction kinetics in micellar surfactant solutions

    KAUST Repository

    Griffiths, I.M.

    2011-08-01

    We investigate the breakdown of a system of micellar aggregates in a surfactant solution following an order-one dilution. We derive a mathematical model based on the Becker-Döring system of equations, using realistic expressions for the reaction constants fit to results from Molecular Dynamics simulations. We exploit the largeness of typical aggregation numbers to derive a continuum model, substituting a large system of ordinary differential equations for a partial differential equation in two independent variables: time and aggregate size. Numerical solutions demonstrate that re-equilibration occurs in two distinct stages over well-separated timescales, in agreement with experiment and with previous theories. We conclude by exposing a limitation in the Becker-Döring theory for re-equilibration of surfactant solutions. © 2011 Elsevier Inc.

  13. Simultaneous Determination of Eosin-Yellow and Ponceau-S Using H-Point Standard Addition Method in Micellar Media

    Directory of Open Access Journals (Sweden)

    Amandeep Kaur

    2012-01-01

    Full Text Available H-point standard addition method (HPSAM is developed for simultaneous determination of eosin-Y and ponceau-s in micellar media. Nickel chloride (NiCl2 is used as chromogenic reagent for complexes formation of eosin-Y and ponceau-S food colorants. The measurements were carried out using sodium lauryl sulphate as a surfactant, in buffered solution at pH 6.0. The concentration range of 0.115-2.53 μg/mL of eosin-Y and 0.159-3.80 μg/mL of ponceau-S. The proposed procedures have been applied successfully for the simultaneous determination of eosin-Y and ponceau-S in synthetic binary mixtures and real samples.

  14. Determination of water-soluble vitamins in multivitamin dietary supplements and in artichokes by micellar electrokinetic chromatography.

    Science.gov (United States)

    Serni, Enrico; Audino, Valeria; Del Carlo, Sara; Manera, Clementina; Saccomanni, Giuseppe; Macchia, Marco

    2013-01-01

    Several procedures of extraction with solvents for the simultaneous determination of vitamin C and some vitamins belonging to the B group (thiamine, riboflavine, nicotinic acid and nicotinamide) in multivitamin preparations and in artichokes (Cynara cardunculus subsp. scolymus [L.] Hegi) were developed. Different experimental conditions were used, in terms of heat treatment, composition and pH of the extraction mixture, with particular attention to high-temperature steps; purification of the extracts with solid phase extraction and stabilisation through lyophilisation were discussed. Analyses of the extracts were conducted by capillary electrophoresis in micellar electrokinetic chromatography modality. Borate buffer at pH 8.2 was used, and sodium dodecyl sulphate was added to the background electrolyte as surfactant. A range of linearity was determined and calibration curves were plotted for all the analytes.

  15. Shape-selective synthesis of non-micellar cobalt oxide (CoO) nanomaterials by microwave irradiations

    International Nuclear Information System (INIS)

    Kundu, Subrata; Jayachandran, M.

    2013-01-01

    Shape-selective formation of CoO nanoparticles has been developed using a simple one-step in situ non-micellar microwave (MW) heating method. CoO NPs were synthesized by mixing aqueous CoCl 2 ·6H 2 O solution with poly (vinyl) alcohol (PVA) in the presence of sodium hydroxide (NaOH). The reaction mixture was irradiated using MW for a total time of 2 min. This process exclusively generated different shapes like nanosphere, nanosheet, and nanodendrite structures just by tuning the Co(II) ion to PVA molar ratios and controlling other reaction parameters. The proposed synthesis method is efficient, straightforward, reproducible, and robust. Other than in catalysis, these cobalt oxide nanomaterials can be used for making pigments, battery materials, for developing solid state sensors, and also as an anisotropy source for magnetic recording.Graphical Abstract

  16. Radiation decomposition of alcohols and chloro phenols in micellar systems; Descomposicion por irradiacion de alcoholes y clorofenoles en sistemas micelares

    Energy Technology Data Exchange (ETDEWEB)

    Moreno A, J

    1999-12-31

    The effect of surfactants on the radiation decomposition yield of alcohols and chloro phenols has been studied with gamma doses of 2, 3, and 5 KGy. These compounds were used as typical pollutants in waste water, and the effect of the water solubility, chemical structure, and the nature of the surfactant, anionic or cationic, was studied. The results show that anionic surfactant like sodium dodecylsulfate (SDS), improve the radiation decomposition yield of ortho-chloro phenol, while cationic surfactant like cetyl trimethylammonium chloride (CTAC), improve the radiation decomposition yield of butyl alcohol. A similar behavior is expected for those alcohols with water solubility close to the studied ones. Surfactant concentrations below critical micellar concentration (CMC), inhibited radiation decomposition for both types of alcohols. However radiation decomposition yield increased when surfactant concentrations were bigger than the CMC. Aromatic alcohols decomposition was more marked than for linear alcohols decomposition. On a mixture of alcohols and chloro phenols in aqueous solution the radiation decomposition yield decreased with increasing surfactant concentration. Nevertheless, there were competitive reactions between the alcohols, surfactants dimers, hydroxyl radical and other reactive species formed on water radiolysis, producing a catalytic positive effect in the decomposition of alcohols. Chemical structure and the number of carbons were not important factors in the radiation decomposition. When an alcohol like ortho-chloro phenol contained an additional chlorine atom, the decomposition of this compound was almost constant. In conclusion the micellar effect depend on both, the nature of the surfactant (anionic or cationic) and the chemical structure of the alcohols. The results of this study are useful for wastewater treatment plants based on the oxidant effect of the hydroxyl radical, like in advanced oxidation processes, or in combined treatment such as

  17. Formation of highly structured cubic micellar lipid nanoparticles of soy phosphatidylcholine and glycerol dioleate and their degradation by triacylglycerol lipase.

    Science.gov (United States)

    Wadsäter, Maria; Barauskas, Justas; Nylander, Tommy; Tiberg, Fredrik

    2014-05-28

    Lipid nanoparticles of reversed internal phase structures, such as cubic micellar (I2) structure show good drug loading ability of peptides and proteins as well as some small molecules. Due to their controllable small size and inner morphology, such nanoparticles are suitable for drug delivery using several different administration routes, including intravenous, intramuscular, and subcutaneous injection. A very interesting system in this regard, is the two component soy phosphatidylcholine (SPC)/glycerol dioleate (GDO) system, which depending on the ratio of the lipid components form a range of reversed liquid crystalline phases. For a 50/50 (w/w) ratio in excess water, these lipids have been shown to form a reversed cubic micellar (I2) phase of the Fd3m structure. Here, we demonstrate that this SPC/GDO phase, in the presence of small quantities (5-10 wt %) of Polysorbate 80 (P80), can be dispersed into nanoparticles, still with well-defined Fd3m structure. The resulting nanoparticle dispersion has a narrow size distribution and exhibit good long-term stability. In pharmaceutical applications, biodegradation pathways of the drug delivery vehicles and their components are important considerations. In the second part of the study we show how the structure of the particles evolves during exposure to a triacylglycerol lipase (TGL) under physiological-like temperature and pH. TGL catalyzes the lipolytic degradation of acylglycerides, such as GDO, to monoglycerides, glycerol, and free fatty acids. During the degradation, the interior phase of the particles is shown to undergo continuous phase transitions from the reversed I2 structure to structures of less negative curvature (2D hexagonal, bicontinuous cubic, and sponge), ultimately resulting in the formation of multilamellar vesicles.

  18. Commercial scale demonstration: enhanced oil recovery by micellar-polymer flood. Annual report, October 1980-September 1981

    Energy Technology Data Exchange (ETDEWEB)

    Howell, J.C.

    1982-05-01

    This commercial scale test, known as the M-1 Project, is located in Crawford County, Illinois. It encompasses 407 acres of Robinson sand reservoir and covers portions of several waterflood projects that were approaching economic limit. The project includes 248 acres developed on a 2.5-acre five-spot pattern and 159 acres developed on a 5.0-acre five-spot pattern. Development work commenced in late 1974 and has previously been reported. Micellar solution (slug) injection was initiated on February 10, 1977, and is now completed. After 10% of a pore volume of micellar slug was injected, injection of 11% pore volume of Dow 700 Pusher polymer was conducted at a concentration of 1156 ppM. At the end of this reporting period, 625 ppM polymer was being injected into the 2.5-acre pattern and 800 ppM polymer was being injected into the 5.0-acre pattern. The oil cut of the 2.5-acre pattern has decreased from 11.0% in September 1980, to 7.9% in September 1981. The 2.5-acre pattern had been on a plateau since May 1980, and as of May 1981 appears to be on a decline. The oil cut of the 5.0-acre pattern has increased from 5.9% in September 1980, to 10.9% in September 1981. The 5.0-acre pattern experienced a sharp increase in oil cut after 34% of a pore volume of total fluid had been injected and appears to be continuing its incline. This fifth annual report is organized under the following three work breakdown structures: fluid injection; production; and performance monitoring.

  19. Enhancing the lateral-flow immunoassay for detection of proteins using an aqueous two-phase micellar system.

    Science.gov (United States)

    Mashayekhi, Foad; Le, Alexander M; Nafisi, Parsa M; Wu, Benjamin M; Kamei, Daniel T

    2012-10-01

    The lateral-flow (immuno)assay (LFA) has been widely investigated for the detection of molecular, macromolecular, and particle targets at the point-of-need due to its ease of use, rapid processing, and minimal power and laboratory equipment requirements. However, for some analytes, such as certain proteins, the detection limit of LFA is inferior to lab-based assays, such as the enzyme-linked immunosorbent assay, and needs to be improved. One solution for improving the detection limit of LFA is to concentrate the target protein in a solution prior to the detection step. In this study, a novel approach was used in the context of an aqueous two-phase micellar system comprised of the nonionic surfactant Triton X-114 to concentrate a model protein, namely transferrin, prior to LFA. Proteins have been shown to partition, or distribute, fairly evenly between the two phases of an aqueous two-phase system, which in turn results in their limited concentration in one of the two phases. Therefore, larger colloidal gold particles decorated with antibodies for transferrin were used in the concentration step to bind to transferrin and aid its partitioning into the top, micelle-poor phase. By manipulating the volume ratio of the two coexisting micellar phases and combining the concentration step with LFA, the transferrin detection limit of LFA was improved by tenfold from 0.5 to 0.05 μg/mL in a predictive manner. In addition to enhancing the sensitivity of LFA, this universal concentration method could also be used to improve other detection assays.

  20. A pH-responsive wormlike micellar system of a noncovalent interaction-based surfactant with a tunable molecular structure.

    Science.gov (United States)

    Kang, Wanli; Wang, Pengxiang; Fan, Haiming; Yang, Hongbin; Dai, Caili; Yin, Xia; Zhao, Yilu; Guo, Shujun

    2017-02-08

    Responsive wormlike micelles are very useful in a number of applications, whereas it is still challenging to create dramatic viscosity changes in wormlike micellar systems. Here we developed a pH-responsive wormlike micellar system based on a noncovalent constructed surfactant, which is formed by the complexation of N-erucamidopropyl-N,N-dimethylamine (UC 22 AMPM) and citric acid at the molar ratio of 3 : 1 (EACA). The phase behavior, aggregate microstructure and viscoelasticity of EACA solutions were investigated by macroscopic appearance observation, rheological and cryo-TEM measurements. It was found that the phase behavior of EACA solutions undergoes transition from transparent viscoelastic fluids to opalescent solutions and then phase separation with white floaters upon increasing the pH. Upon increasing the pH from 2.03 to 6.17, the viscosity of wormlike micelles in the transparent solutions continuously increased and reached ∼683 000 mPa s at pH 6.17. As the pH was adjusted to 7.31, the opalescent solution shows a water-like flowing behaviour and the η 0 rapidly declines to ∼1 mPa s. Thus, dramatic viscosity changes of about 6 magnitudes can be triggered by varying the pH values without any deterioration of the EACA system. This drastic variation in rheological behavior is attributed to the pH dependent interaction between UC 22 AMPM and citric acid. Furthermore, the dependence on concentration and temperature of the rheological behavior of EACA solutions was also studied to assist in obtaining the desired pH-responsive viscosity changes.

  1. Sequential optimization of methotrexate encapsulation in micellar nano-networks of polyethyleneimine ionomer containing redox-sensitive cross-links.

    Science.gov (United States)

    Abolmaali, Samira Sadat; Tamaddon, Ali; Yousefi, Gholamhossein; Javidnia, Katayoun; Dinarvand, Rasoul

    2014-01-01

    A functional polycation nanonetwork was developed for delivery of water soluble chemotherapeutic agents. The complexes of polyethyleneimine grafted methoxy polyethylene glycol (PEI-g-mPEG) and Zn(2+) were utilized as the micellar template for cross-linking with dithiodipropionic acid, followed by an acidic pH dialysis to remove the metal ion from the micellar template. The synthesis method was optimized according to pH, the molar ratio of Zn(2+), and the cross-link ratio. The atomic force microscopy showed soft, discrete, and uniform nano-networks. They were sensitive to the simulated reductive environment as determined by Ellman's assay. They showed few positive ζ potential and an average hydrodynamic diameter of 162±10 nm, which decreased to 49±11 nm upon dehydration. The ionic character of the nano-networks allowed the achievement of a higher-loading capacity of methotrexate (MTX), approximately 57% weight per weight, depending on the cross-link and the drug feed ratios. The nano-networks actively loaded with MTX presented some suitable properties, such as the hydrodynamic size of 117±16 nm, polydispersity index of 0.22, and a prolonged swelling-controlled release profile over 24 hours that boosted following reductive activation of the nanonetwork biodegradation. Unlike the PEI ionomer, the nano-networks provided an acceptable cytotoxicity profile. The drug-loaded nano-networks exhibited more specific cytotoxicity against human hepatocellular carcinoma cells if compared to free MTX at concentrations above 1 μM. The enhanced antitumor activity in vitro might be attributed to endocytic entry of MTX-loaded nano-networks that was found in the epifluorescence microscopy experiment for the fluorophore-labeled nano-networks.

  2. Radiation decomposition of alcohols and chloro phenols in micellar systems; Descomposicion por irradiacion de alcoholes y clorofenoles en sistemas micelares

    Energy Technology Data Exchange (ETDEWEB)

    Moreno A, J

    1998-12-31

    The effect of surfactants on the radiation decomposition yield of alcohols and chloro phenols has been studied with gamma doses of 2, 3, and 5 KGy. These compounds were used as typical pollutants in waste water, and the effect of the water solubility, chemical structure, and the nature of the surfactant, anionic or cationic, was studied. The results show that anionic surfactant like sodium dodecylsulfate (SDS), improve the radiation decomposition yield of ortho-chloro phenol, while cationic surfactant like cetyl trimethylammonium chloride (CTAC), improve the radiation decomposition yield of butyl alcohol. A similar behavior is expected for those alcohols with water solubility close to the studied ones. Surfactant concentrations below critical micellar concentration (CMC), inhibited radiation decomposition for both types of alcohols. However radiation decomposition yield increased when surfactant concentrations were bigger than the CMC. Aromatic alcohols decomposition was more marked than for linear alcohols decomposition. On a mixture of alcohols and chloro phenols in aqueous solution the radiation decomposition yield decreased with increasing surfactant concentration. Nevertheless, there were competitive reactions between the alcohols, surfactants dimers, hydroxyl radical and other reactive species formed on water radiolysis, producing a catalytic positive effect in the decomposition of alcohols. Chemical structure and the number of carbons were not important factors in the radiation decomposition. When an alcohol like ortho-chloro phenol contained an additional chlorine atom, the decomposition of this compound was almost constant. In conclusion the micellar effect depend on both, the nature of the surfactant (anionic or cationic) and the chemical structure of the alcohols. The results of this study are useful for wastewater treatment plants based on the oxidant effect of the hydroxyl radical, like in advanced oxidation processes, or in combined treatment such as

  3. Intermolecular electron transfer between coumarin dyes and aromatic amines in Triton-X-100 micellar solutions: Evidence for Marcus inverted region

    Science.gov (United States)

    Kumbhakar, Manoj; Nath, Sukhendu; Mukherjee, Tulsi; Pal, Haridas

    2004-02-01

    Photoinduced electron transfer (ET) between coumarin dyes and aromatic amines has been investigated in Triton-X-100 micellar solutions and the results have been compared with those observed earlier in homogeneous medium. Significant static quenching of the coumarin fluorescence due to the presence of high concentration of amines around the coumarin fluorophore in the micelles has been observed in steady-state fluorescence studies. Time-resolved studies with nanosecond resolutions mostly show the dynamic part of the quenching for the excited coumarin dyes by the amine quenchers. A correlation of the quenching rate constants, estimated from the time-resolved measurements, with the free energy changes (ΔG0) of the ET reactions shows the typical bell shaped curve as predicted by Marcus outer-sphere ET theory. The inversion in the ET rates for the present systems occurs at an exergonicity (-ΔG0) of ~0.7-0.8 eV, which is unusually low considering the polarity of the Palisade layer of the micelles where the reactants reside. Present results have been rationalized on the basis of the two dimensional ET model assuming that the solvent relaxation in micellar media is much slower than the rate of the ET process. Detailed analysis of the experimental data shows that the diffusional model of the bimolecular quenching kinetics is not applicable for the ET reactions in the micellar solutions. In the present systems, the reactions can be better visualized as equivalent to intramolecular electron transfer processes, with statistical distribution of the donors and acceptors in the micelles. A low electron coupling (Vel) parameter is estimated from the correlation of the experimentally observed and the theoretically calculated ET rates, which indicates that the average donor-acceptor separation in the micellar ET reactions is substantially larger than for the donor-acceptor contact distance. Comparison of the Vel values in the micellar solution and in the donor-acceptor close

  4. Determination of lysergic acid diethylamide (LSD) in mouse blood by capillary electrophoresis/ fluorescence spectroscopy with sweeping techniques in micellar electrokinetic chromatography.

    Science.gov (United States)

    Fang, Ching; Liu, Ju-Tsung; Chou, Shiu-Huey; Lin, Cheng-Huang

    2003-03-01

    The separation and on-line concentration of lysergic acid diethylamide (LSD) in mouse blood was achieved by means of capillary electrophoresis/fluorescence spectroscopy using sodium dodecyl sulfate (SDS) as the surfactant. Techniques involving on-line sample concentration, including sweeping micellar electrokinetic chromatography (sweeping-MEKC) and cation-selective exhaustive injection-sweep-micellar electrokinetic chromatography (CSEI-sweep-MEKC) were applied; the optimum on-line concentration and separation conditions were determined. In the analysis of an actual sample, LSD was found in a blood sample from a test mouse (0.1 mg LSD fed to a 20 g mouse; approximately 1/10 to the value of LD(50)). As a result, 120 and 30 ng/mL of LSD was detected at 20 and 60 min, respectively, after ingestion of the doses.

  5. Micellar modified spectrophotometric determination of nitrobenzenes based upon reduction with tin(II), diazotisation and coupling with the Bratton-Marshall reagent.

    Science.gov (United States)

    Escrig-Tena, I; Alvarez Rodríguez, L; Esteve-Romero, J; García-Alvarez-Coque, M C

    1998-09-01

    Nitrobenzenes, such as the antibiotic chloramphenicol, the vasodilator nicardipine, and the herbicides dinitramin, dinobuton, fenitrothion, methylparathion, oxyfluorfen, parathion, pendimethalin, quintozene, and trifluralin, were determined by using a spectrophotometric method in the visible region (540 nm). The method was based on the reduction of the nitrobenzenes to arylamines with tin(II) chloride, diazotisation of the arylamines and coupling of the diazonium ions with the Bratton-Marshall reagent. The two latter reactions were performed in a micellar medium of sodium dodecyl sulphate. The linear calibration range was 2x10(-6) to 7x10(-5) M (r>0.999), with limits of detection in the 10(-7) M level, which is 2-6 fold lower with respect to the corresponding spectrophotometric procedure in non-micellar medium. The procedure was applied to the analysis of the compounds in commercial preparations (pharmaceuticals and herbicide formulations) and in water samples, with good recoveries.

  6. Local Content

    CSIR Research Space (South Africa)

    Gibberd, Jeremy

    2016-10-01

    Full Text Available Local content refers to materials and products made in a country as opposed those that are imported. There is an increasing interest in the concept of local content as a means of supporting local economies and providing jobs (Belderbos & Sleuwaegen...

  7. Micellar and analytical implications of a new potentiometric PVC sensor based on neutral ion-pair complexes of dodecylmethylimidazolium bromide-sodium dodecylsulfate.

    Science.gov (United States)

    Sanan, Reshu; Mahajan, Rakesh Kumar

    2013-03-15

    With an aim to characterize the micellar aggregates of imidazolium based ionic liquids, a new potentiometric PVC sensor based on neutral ion-pair complexes of dodecylmethylimidazolium bromide-sodium dodecylsulfate (C12MeIm(+)DS(-)) has been developed. The electrode exhibited a linear response for the concentration range of 7.9×10(-5)-9.8×10(-3) M with a super-Nernstian slope of 92.94 mV/decade, a response time of 5 s and critical micellar concentration (cmc) of 10.09 mM for C12MeImBr. The performance of the electrode in investigating the cmc of C12MeImBr in the presence of two drugs [promazine hydrochloride (PMZ) and promethazine hydrochloride (PMT)] and three triblock copolymers (P123, L64 and F68) has been found to be satisfactory on comparison with conductivity measurements. Various micellar parameters have been evaluated for the binary mixtures of C12MeImBr with drugs and triblock copolymers using Clint's, Rubingh's, and Motomura's approach. Thus the electrode offers a simple, straightforward and relatively fast technique for the characterization of micellar aggregates of C12MeImBr, complementing existing conventional techniques. Further, the analytical importance of proposed C12MeIm(+)-ISE as end point indicator in potentiometric titrations and for direct determination of cationic surfactants [cetylpyridinium chloride (CPC), tetradecyltrimethylammonium bromide (TTAB), benzalkonium chloride (BC)] in some commercial products was judged by comparing statistically with classical two-phase titration methods. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. The Oral Bioavailability of Trans-Resveratrol from a Grapevine-Shoot Extract in Healthy Humans is Significantly Increased by Micellar Solubilization.

    Science.gov (United States)

    Calvo-Castro, Laura A; Schiborr, Christina; David, Franziska; Ehrt, Heidi; Voggel, Jenny; Sus, Nadine; Behnam, Dariush; Bosy-Westphal, Anja; Frank, Jan

    2018-05-01

    Grapevine-shoot extract Vineatrol30 contains abundant resveratrol monomers and oligomers with health-promoting potential. However, the oral bioavailability of these compounds in humans is low (˂1-2%). The aim of this study was to improve the oral bioavailability of resveratrol from vineatrol by micellar solubilization. Twelve healthy volunteers (six women, six men) randomly ingested a single dose of 500 mg vineatrol (30 mg trans-resveratrol, 75 mg trans-ε-viniferin) as native powder or liquid micelles. Plasma and urine were collected at baseline and over 24 h after intake. Resveratrol and viniferin were analyzed by HPLC. The area under the plasma concentration-time curve (AUC) and mean maximum plasma trans-resveratrol concentrations were 5.0-fold and 10.6-fold higher, respectively, after micellar supplementation relative to the native powder. However, no detectable amounts of trans-ε-viniferin were found in either plasma or urine. The transepithelial permeability of trans-resveratrol and trans-ε-viniferin across differentiated Caco-2 monolayers was consistent to the absorbed fractions in vivo. The oral bioavailability of trans-resveratrol from the grapevine-shoot extract Vineatrol30 was significantly increased using a liquid micellar formulation, without any treatment-related adverse effects, making it a suitable system for improved supplementation of trans-resveratrol. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Micellar HPLC Method for Simultaneous Determination of Ethamsylate and Mefenamic Acid in Presence of Their Main Impurities and Degradation Products.

    Science.gov (United States)

    Ibrahim, Fawzia; Sharaf El-Din, Mohie K; El-Deen, Asmaa Kamal; Shimizu, Kuniyoshi

    2017-01-01

    An eco-friendly sensitive, rapid and less hazardous micellar liquid chromatographic method was developed and validated for the simultaneous analysis of ethamsylate (ETM) and mefenamic acid (MFA) in the presence of hydroquinone (HQ) and 2,3-dimethylaniline (DMA) the main impurities of ETM and MFA, respectively. Good chromatographic separation was attained using Eclipse XDB-C8 column (150 mm × 4.6 mm, 5 μm particle size) adopting UV detection at 300 nm with micellar mobile phase consisting of 0.12 M sodium dodecyl sulfate, 0.3% triethylamine and 15% 2-propanol in 0.02 M orthophosphoric acid (pH 7.0) at 1.0 mL/min. The analytes were well resolved in <6.0 min, ETM (t R = 1.55 min), HQ (t R = 1.95 min), MFA (t R = 4.55 min) and DMA (t R = 5.80 min). Different validation parameters were examined as recommended by international conference on harmonization (ICH) guidelines. The method was linear over the concentration ranges of 0.5-18.0, 0.5-20.0, 0.01-0.5 and 0.02-0.2 µg/mL with limits of detection of 0.118, 0.159, 0.005 and 0.005 µg/mL and limits of quantification of 0.358, 0.482, 0.014 and 0.015 µg/mL for ETM, MFA, HQ and DMA, respectively. The suggested method was successfully applied for the determination of the two drugs in their bulk powder, laboratory-prepared mixtures, single-ingredient and co-formulated tablets. The obtained results were in accordance with those of the comparison method. The method can also detect trace amounts of HQ and DMA as the main impurities of ETM and MFA, respectively, within the BP limit (0.1%) for both impurities. Furthermore, it is a stability-indicating one for the determination of ETM in its pure form, single-component tablet and co-formulated tablets with other drugs. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  10. αvβ3 integrin-targeted micellar mertansine prodrug effectively inhibits triple-negative breast cancer in vivo

    Directory of Open Access Journals (Sweden)

    Zhong P

    2017-10-01

    Full Text Available Ping Zhong,1,2 Xiaolei Gu,1,2 Ru Cheng,1,2 Chao Deng,1,2 Fenghua Meng,1,2 Zhiyuan Zhong1,2 1Biomedical Polymers Laboratory, 2Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, China Abstract: Antibody-mertansine (DM1 conjugates (AMCs are among the very few active targeting therapeutics that are approved or clinically investigated for treating various cancers including metastatic breast cancer. However, none of the AMCs are effective for the treatment of triple-negative breast cancers (TNBCs. Here, we show that cRGD-decorated, redox-activatable micellar mertansine prodrug (cRGD-MMP can effectively target and deliver DM1 to αvβ3 integrin overexpressing MDA-MB-231 TNBC xenografts in nude mice, resulting in potent tumor growth inhibition. 3-(4,5-Dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT assays showed that cRGD-MMP had obvious targetability to MDA-MB-231 cells with a low half-maximal inhibitory concentration (IC50 of 0.18 µM, which was close to that of free DM1 and 2.2-fold lower than that of micellar mertansine prodrug (MMP; nontargeting control. The confocal microscopy studies demonstrated that cRGD-MMP mediated a clearly more efficient cellular uptake and intracellular release of doxorubicin (used as a fluorescent anticancer drug model in MDA-MB-231 cells. Notably, cRGD-MMP loaded with 1,1'-dioctadecyltetramethyl indotricarbocyanine iodide (DiR; a hydrophobic near-infrared dye was shown to quickly accumulate in the MDA-MB-231 tumor with strong DiR fluorescence from 2 to 24 h post injection. MMP loaded with DiR could also accumulate in the tumor, although significantly less than cRGD-MMP. The biodistribution studies revealed a high DM1 accumulation of 8.1%ID/g in the tumor for cRGD-MMP at 12 h post injection. The therapeutic results demonstrated that cRGD-MMP effectively suppressed MDA-MB-231 tumor growth at

  11. Sequential optimization of methotrexate encapsulation in micellar nano-networks of polyethyleneimine ionomer containing redox-sensitive cross-links

    Directory of Open Access Journals (Sweden)

    Abolmaali SS

    2014-06-01

    Full Text Available Samira Sadat Abolmaali,1 Ali Tamaddon,1,2 Gholamhossein Yousefi,1,2 Katayoun Javidnia,3 Rasoul Dinarvand41Department of Pharmaceutics, Shiraz School of Pharmacy, 2Center for Nanotechnology in Drug Delivery, 3Medicinal and Natural Products Chemistry Research Center, Shiraz University of Medical Sciences, Shiraz, Iran; 4Nanotechnology Research Centre, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, IranAbstract: A functional polycation nanonetwork was developed for delivery of water soluble chemotherapeutic agents. The complexes of polyethyleneimine grafted methoxy polyethylene glycol (PEI-g-mPEG and Zn2+ were utilized as the micellar template for cross-linking with dithiodipropionic acid, followed by an acidic pH dialysis to remove the metal ion from the micellar template. The synthesis method was optimized according to pH, the molar ratio of Zn2+, and the cross-link ratio. The atomic force microscopy showed soft, discrete, and uniform nano-networks. They were sensitive to the simulated reductive environment as determined by Ellman's assay. They showed few positive ζ potential and an average hydrodynamic diameter of 162±10 nm, which decreased to 49±11 nm upon dehydration. The ionic character of the nano-networks allowed the achievement of a higher-loading capacity of methotrexate (MTX, approximately 57% weight per weight, depending on the cross-link and the drug feed ratios. The nano-networks actively loaded with MTX presented some suitable properties, such as the hydrodynamic size of 117±16 nm, polydispersity index of 0.22, and a prolonged swelling-controlled release profile over 24 hours that boosted following reductive activation of the nanonetwork biodegradation. Unlike the PEI ionomer, the nano-networks provided an acceptable cytotoxicity profile. The drug-loaded nano-networks exhibited more specific cytotoxicity against human hepatocellular carcinoma cells if compared to free MTX at concentrations above 1 µM. The

  12. Field-Amplified Sample Injection-Micellar Electrokinetic Chromatography for the Determination of Benzophenones in Food Simulants

    Directory of Open Access Journals (Sweden)

    Cristina Félez

    2015-07-01

    Full Text Available A field-amplified sample injection-micellar electrokinetic chromatography (FASI-MEKC method for the determination of 14 benzophenones (BPs in a food simulant used in migration studies of food packaging materials was developed, allowing almost baseline separation in less than 21 min. The use of a 10 mM sodium dodecyl sulfate (SDS solution as sample matrix was mandatory to achieve FASI enhancement of the analyzed BPs. A 21- to 784-fold sensitivity enhancement was achieved with FASI-MEKC, obtaining limits of detection down to 5.1–68.4 µg/L, with acceptable run-to-run precisions (RSD values lower than 22.3% and accuracy (relative errors lower than 21.0%. Method performance was evaluated by quantifying BPs in the food simulant spiked at 500 µg/L (bellow the established specific migration limit for BP (600 µg/L by EU legislation. For a 95% confidence level, no statistical differences were observed between found and spiked concentrations (probability at the confidence level, p value, of 0.55, showing that the proposed FASI-MEKC method is suitable for the analysis of BPs in food packaging migration studies at the levels established by EU legislation.

  13. On the appearance of vorticity and gradient shear bands in wormlike micellar solutions of different CPCl/salt systems

    Energy Technology Data Exchange (ETDEWEB)

    Mütze, Annekathrin, E-mail: muetzea@ethz.ch; Heunemann, Peggy; Fischer, Peter [ETH Zürich, Institute of Food, Nutrition and Health, Schmelzbergstrasse 9, 8092 Zürich (Switzerland)

    2014-11-01

    Wormlike micellar salt/surfactant solutions (X-salicylate, cetylpyridinium chloride) are studied with respect to the applied shear stress, concentration, temperature, and composition of the counterions (X = lithium, sodium, potassium, magnesium, and calcium) of the salicylate salt solute to determine vorticity and gradient shear bands. A combination of rheological measurements, laser technique, video analysis, and rheo-small-angle neutron scattering allow for a detailed exploration of number and types of shear bands. Typical flow curves of the solutions show Newtonian, shear-thinning, and shear-thickening flow behavior. In the shear-thickening regime, the solutions show vorticity and gradient shear bands simultaneously, in which vorticity shear bands dominate the visual effect, while gradient shear bands always coexist and predominate the rheological response. It is shown that gradient shear bands change their phases (turbid, clear) with the same frequency as the shear rate oscillates, whereas vorticity shear bands change their phases with half the frequency of the shear rate. Furthermore, we show that with increasing molecular mass of the counterions the number of gradient shear bands increases, while the number of vorticity shear bands remains constant. The variation of temperature, shear stress, concentration, and counterions results in a predictable change in the rheological behavior and therefore allows adjustment of the number of vorticity shear bands in the shear band regime.

  14. Pressurized liquid extracts from Spirulina platensis microalga. Determination of their antioxidant activity and preliminary analysis by micellar electrokinetic chromatography.

    Science.gov (United States)

    Herrero, Miguel; Ibáñez, Elena; Cifuentes, Alejandro; Señoráns, Javier

    2004-08-27

    In this work, different extracts from the microalga Spirulina platensis are obtained using pressurized liquid extraction (PLE) and four different solvents (hexane, light petroleum, ethanol and water). Different extraction temperatures (115 and 170 degrees C) were tested using extraction times ranging from 9 to 15 min. The antioxidant activity of the different extracts is determined by means of an in vitro assay using a free radical method. Moreover, a new and fast method is developed using micellar electrokinetic chromatography with diode array detection (MEKC-DAD) to provide a preliminary analysis on the composition of the extracts. This combined application (i.e., in vitro assays plus MEKC-DAD) allowed the fast characterization of the extracts based on their antioxidant activity and the UV-vis spectra of the different compounds found in the extracts. To our knowledge, this work shows for the first time the great possibilities of the combined use of PLE-in vitro assay-MEKC-DAD to investigate natural sources of antioxidants.

  15. Highly Viscoelastic Reverse Wormlike Micellar Systems from a Mixture of Lecithin, Polyglycerol Fatty Acid Monoesters, and an Oil.

    Science.gov (United States)

    Hashizaki, Kaname; Imai, Miko; Yako, Shuhei; Tsusaka, Hitomi; Sakanishi, Yuichi; Saito, Yoshihiro; Fujii, Makiko

    2017-09-01

    We report new lecithin reverse wormlike micelles with high viscoelasticity formed using lecithin/polyglycerol fatty acid monoester (PGLFA)/oil systems. In this study, the influence of the amphiphilicity (i.e., hydrophile-lipophile balance, HLB) of PGLFA on the phase behavior and rheological properties of reverse wormlike micelles was investigated in detail. PGLFAs with degrees of polymerization of polyglycerol varying between 6-40 and constituent fatty acids with chains between 6-18 carbon atoms long were used. Partial phase diagrams of the lecithin/PGLFA/n-decane systems indicated that the appropriate PGLFA could change the lecithin/oil solution into a highly viscoelastic solution comprising reverse wormlike micelles. Rheological measurements showed that all systems that formed reverse wormlike micelles exhibited an unusual phenomenon called "shear-thickening". Furthermore, reverse wormlike micelles grew as the PGLFA concentration increased and the zero-shear viscosity (η 0 ) of the solution rapidly increased. Our results indicate that the magnitude of the maximum η 0 depends on the degree of polymerization of the constituent polyglycerol in the PGLFA, while the size of the reverse micellar region and the highly viscous region in the phase diagram depends on the HLB value of the PGLFA.

  16. Lecithin organogel: A unique micellar system for the delivery of bioactive agents in the treatment of skin aging

    Directory of Open Access Journals (Sweden)

    Sushil Raut

    2012-02-01

    Full Text Available Skin aging is an unavoidable aspect of human life. Premature skin aging can result from poor care, environmental pollutants, and ultraviolet radiation exposure. Wrinkles, lines, spots, uneven skin tone, and pigmentation are often indicators of skin aging. One cannot avoid aging but cosmetics and pharmaceutical approaches can minimize and delay the damage. Topical applications of biocompatible and biodegradable vehicles have been explored for delivering anti-aging compounds. Lecithin organogel (LO is an effective vehicle for topical delivery of many bioactive agents used in aging treatment. Lecithin is cell component isolated from soya beans or eggs and purified to show excellent gelation in non-polar solvents when combined with water. LO can form a heat-stable, resistant to microbial growth, visco-elastic, optically transparent, and non-birefringent micellar system. It serves as an organic medium to enhance dermal permeation of poorly permeable drugs by effectively partitioning into the skin. Its ability to dissolve in hydrophilic as well as in lipophilic drugs makes it a dynamic vehicle, which can be explored as a carrier for anti-aging agents.

  17. Micellar Enhanced Ultrafiltration for the Removal of Polycyclic Aromatic Hydrocarbons (PAHs Mixtures in Underground Contaminated Water in Oman

    Directory of Open Access Journals (Sweden)

    Mohamed Aoudia

    2011-12-01

    Full Text Available In an attempt to analyze polycyclic aromatic hydrocarbons (PAHs in diesel contaminated underground water in Oman (Rustaq, Gas chromatography-Mass spectrometry was first used to determine the different concentrations in a standard mixture containing 16 PAHs. Retention time and calibration curves were obtained for all aromatic compounds and were used to identify a given analyte as well as its concentration in the contaminated underground water. Micellar enhanced ultrafiltration (MEUF was then used to treat standard aqueous solution of PAHs at low concentration (~ 1 ppb using an edible nonionic surfactant (Tween 80. The totality of the mixture components was completely rejected. Within the experimental detection limit (± 0.01 ppb, the residual PAH concentrations were less than 0.01 ppb in accord with the allowed concentrations in drinking water. Likewise, excellent rejections of PAHs in MEUF treatment of diesel contaminated underground water at an Omani site (Rustaq were observed. The concentration of PAHs was reduced to less than 0.01 ppb, the accepted limit for the most toxic member of the PAH group (benzo(apyrene.

  18. Deciphering the fluorescence resonance energy transfer from denatured transport protein to anthracene 1,5 disulphonate in reverse micellar environment

    Science.gov (United States)

    Singharoy, Dipti; Bhattacharya, Subhash Chandra

    2017-12-01

    Constrained environmental effect inside AOT reverse micellar media has been employed in this work to collect the information about energy transfer efficacy between sodium salt of anthracene 1,5 disulphonate (1,5-AS) with model transport proteins, bovine serum albumin (BSA), and human serum albumin (HSA). Steady state, time-resolved fluorescence and circular dichroism techniques have been used for this purpose and corresponding Fӧrster-type resonance energy transfer (FRET) from tryptophan residues to 1,5-AS indicates that 1,5-AS binds in the vicinity of the tryptophan residue (BSA and HSA) with equal strength. Indication of protein damage from fluorescence data and its confirmation has been measured from CD measurement. Molecular modeling study hereby plays a crucial role to predict the minimum energy docked conformation of the probe inside the protein environment. From the docked conformation the distance between 1,5-AS and tryptophan moiety of BSA/HSA has successfully explained the FRET possibility between them. A comparative modeling study between BSA and HSA with 1,5-AS assigning their binding site within specific amino acids plays a crucial role in support of the FRET study.

  19. Capillaries modified by noncovalent anionic polymer adsorption for capillary zone electrophoresis, micellar electrokinetic capillary chromatography and capillary electrophoresis mass spectrometry

    DEFF Research Database (Denmark)

    Bendahl, L; Hansen, S H; Gammelgaard, Bente

    2001-01-01

    A simple coating procedure for generation of a high and pH-independent electroosmotic flow in capillary zone electrophoresis (CZE) and micellar electrokinetic capillary chromatography (MEKC) is described. The bilayer coating was formed by noncovalent adsorption of the ionic polymers Polybrene...... capillaries was (4.9+/-0.1) x 10(-4) cm2V(-1)s(-1) in a pH-range of 2-10 (ionic strength = 30 mM). When alkaline compounds were used as test substances intracapillary and intercapillary migration time variations (n = 6) were less than 1% relative standard deviation (RSD) and 2% RSD, respectively in the entire...... pH range. The coating was fairly stable in the presence of sodium dodecyl sulfate, and this made it possible to perform fast MEKC separations at low pH. When neutral compounds were used as test substances, the intracapillary migration time variations (n = 6) were less than 2% RSD in a pH range of 2...

  20. Rapid determination of piracetam in human plasma and cerebrospinal fluid by micellar electrokinetic chromatography with sample direct injection.

    Science.gov (United States)

    Yeh, Hsin-Hua; Yang, Yuan-Han; Ko, Ju-Yun; Chen, Su-Hwei

    2006-07-07

    A simple micellar electrokinetic chromatography (MEKC) method with UV detection at 200 nm for analysis of piracetam in plasma and in cerebrospinal fluid (CSF) by direct injection without any sample pretreatment is described. The separation of piracetam from biological matrix was performed at 25 degrees C using a background electrolyte consisting of Tris buffer with sodium dodecyl sulfate (SDS) as the electrolyte solution. Several parameters affecting the separation of the drug from biological matrix were studied, including the pH and concentrations of the Tris buffer and SDS. Under optimal MEKC condition, good separation with high efficiency and short analyses time is achieved. Using imidazole as an internal standard (IS), the linear ranges of the method for the determination of piracetam in plasma and in CSF were all between 5 and 500 microg/mL; the detection limit of the drug in plasma and in CSF (signal-to-noise ratio=3; injection 0.5 psi, 5s) was 1.0 microg/mL. The applicability of the proposed method for determination of piracetam in plasma and CSF collected after intravenous administration of 3g piracetam every 6h and oral administration 1.2g every 6h in encephalopathy patients with aphasia was demonstrated.

  1. Effect of low concentration sodium dodecyl sulfate on the electromigration of palonosetron hydrochloride stereoisomers in micellar electrokinetic chromatography.

    Science.gov (United States)

    Hu, Shao-Qiang; Wang, Gui-Xia; Guo, Wen-Bo; Guo, Xu-Ming; Zhao, Min

    2014-05-16

    The effect of low concentrations of sodium dodecyl sulfate (SDS) on the separation of palonosetron hydrochloride (PALO) stereoisomers by micellar electrokinetic chromatography (MEKC) has been investigated. It was found that the addition of SDS prolongs the migration time and the migration order of four stereoisomers changes regularly with the SDS concentration. Good separations for all the four stereoisomers were achieved at appropriate SDS concentration. The effect of SDS on the electromigration (mobilities) of PALO stereoisomers has been studied, in order to explain its effect on the separation by MEKC. It was found that low concentrations of SDS added into the separation media forms negatively charged complexes with PALO stereoisomers and hence reverses their electromigration direction. Furthermore, the migration order between two enantiomeric pairs is also reversed because the enantiomeric pair with a bigger positive mobility than that of another pair turns to have a bigger negative mobility when bound with SDS. Based on these results, the effect of SDS on the MEKC separation of PALO stereoisomers was elucidated reasonably. The performance of the developed chiral MEKC method was validated by the analysis of a real sample. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Macroscopic and microscopic structural integrity in magnetic colloids-cationic micellar solution: Rheology, SANS and magneto-optical study

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Rajesh, E-mail: rjp@bhavuni.ed [Department of Physics, Bhavnagar University, Bhavnagar 364 022 (India); Upadhyay, R.V., E-mail: rvu.as@ecchanga.ac.i [Charotar Institute of Applied Sciences, Education Campus, Changa 388421, Anand, Gujarat (India); Aswal, V.K. [Solid State Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Joshi, J.V.; Goyal, P.S. [UGC- DAE Consortium for Scientific Research, Mumbai Centre, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

    2011-03-15

    A stable mixture of two colloid system composed of double surfactant coated aqueous nanomagnetic fluid and aqueous micellar solution of cationic micelles of cetyletrymethyl ammonium bromide (CTABr) is prepared as a function of nanomagnetic fluid concentration. This mixed system is analyzed using three techniques such as zero field and field induced viscosity measurements, Small Angle Neutron Scattering technique and magneto-optical birefringence measurements. In field induced viscosity measurement it is observed that even 20% magnetic fluid concentration in CTABr aqueous solution shows 75% increase in viscosity compared to pure magnetic fluid. This suggests that in presence of CTABr micelles, a novel magneto rheological effect for low concentration of magnetic fluid is observed. From SANS measurements it is observed that aggregation number and a/b ratio increases with magnetic fluid concentration and magnetic birefringence reveals non-superimpose behavior of normalized field induced retardation. Results of these experiments are compared and indicate zero fields and field induced structural integrity between magnetic particles and soft micelles. - Research Highlights: {yields} This study exhibits zero field and field induced structural integrity between soft micelles and magnetic nanoparticles. {yields} The techniques used are viscosity measurements, Small Angle Neutron Scattering technique and magneto-optical birefringence. {yields} Study is useful for magnetic hyperthermia via micelles, as soft actuators, as an artificial micro-muscles, micro-manipulators, etc.

  3. Sensitive determination of pyrrolizidine alkaloids in Tussilago farfara L. by field-amplified, sample-stacking, sweeping micellar electrokinetic chromatography.

    Science.gov (United States)

    Cao, Kun; Xu, Yi; Mu, Xiuni; Zhang, Qing; Wang, Renjie; Lv, Junjiang

    2016-11-01

    Pyrrolizidine alkaloids are the toxic components in Tussilago farfara L. Due to the lack of standard substances for quantitative analysis and traces of pyrrolizidine alkaloids in total alkaloids, the full quality control of Tussilago farfara L has been limited. In this study, we aimed to solve the difficulty of determination of pyrrolizidine alkaloids and identify more components in the total alkaloids. An on-line preconcentration method has been applied to improve determining sensitivity of pyrrolizidine alkaloids in Tussilago farfara L. in which included field-amplified sample stacking and sweeping in micellar electrokinetic capillary chromatography. The main parameters that affected separation and stacking efficiency were investigated in details. Under the optimal conditions, the sensitivity enhancement factors obtained by the developed method for the analytes were from 15- to 12-fold, the limits of detection of senkirkine and senecionine were 2∼5 μg/L. Senkirkine and senecionine have been detected in alkaloids (c) of Tussilago farfara L, along ferulic acid methyl ester and methyl caffeate. The developed method was also applied to the analysis of acid extraction (a) of Tussilago farfara L, and senkirkine could be detected directly. The results indicated that the developed method is feasible for the analysis of pyrrolizidine alkaloids in Tussilago farfara L with good recoveries. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Synthesis and evaluation of poly(styrene-co-maleic acid) micellar nanocarriers for the delivery of tanespimycin

    Science.gov (United States)

    Larson, Nate; Greish, Khaled; Bauer, Hillevi; Maeda, Hiroshi; Ghandehari, Hamidreza

    2011-01-01

    Polymeric micelles carrying the heat shock protein 90 inhibitor tanespimycin (17-N-Allylamino-17-demethoxygeldanamycin) were synthesized using poly(styrene-co-maleic acid) (SMA) copolymers and evaluated in vitro and in vivo. SMA-tanespimycin micelles were prepared with a loading efficiency of 93%. The micelles incorporated 25.6% tanespimycin by weight, exhibited a mean diameter of 74 ± 7 nm by dynamic light scattering and a zeta potential of -35 ± 3 mV. Tanespimycin was released from the micelles in a controlled manner in vitro, with 62% released in 24 hours from a pH 7.4 buffer containing bovine serum albumin. The micellar drug delivery systems for tanespimycin showed potent activity against DU145 human prostate cancer cells, with an IC50 of 230 nM. They further exhibited potent anti-cancer activity in vivo in nu/nu mice bearing subcutaneous DU145 human prostate cancer tumor xenografts, with significantly higher anticancer efficacy as measured by tumor regression when compared to free tanespimycin at an equivalent single dose of 10 mg/kg. These data suggest further investigation of SMA-tanespimycin as a promising agent in the treatment of prostate cancer. PMID:21856392

  5. Magnetic and micellar effects on photoreactions. 1. 13C isotopic enrichment of dibenzyl ketone via photolysis in aqueous detergent solution

    International Nuclear Information System (INIS)

    Turro, N.J.; Chow, M.F.; Chung, C.J.; Kraeutler, B.

    1981-01-01

    The photolysis of dibenzyl ketone (DBK) in homogeneous organic solutions and in micelle-containing detergent solutions has been investigated from the standpoint of determining the extent and location of 13 C enrichment that occurs. In a series of experiments it is established that for incomplete conversions the residual, recovered DBK is enriched in 13 C relative to the initial unphotolyzed DBK. The efficiency of the 13 C/ 12 C separation is shown to be characterized by an isotope enrichment parameter, α, which is independent of the extent of conversion. A combination of mass spectrometry and nuclear magnetic resonance spectroscopy provides support for the primary location of the 13 C enrichment at C-1 (the carbonyl carbon) with a lesser but significant enrichment at C-2 (the methylene carbon). A very small but experimentally distinct enrichment of the aromatic rings is indicated by 13 C NMR analysis. An isomer of DBK, 1-phenyl-4'-methylacetophenone (PMAP) is formed as a minor product of photolysis in micellar solutions. PMAP, like the recovered, residual DBK, is found to be substantially enriched in 13 C relative to the starting DBK. The magnitude of α is found to be significantly influenced by the application of laboratory magnetic fields to the photolysis sample. The latter result, along with the unusually large magnitude of α, suggests that the mechanism involved in isotopic enrichment is not dominated by kinetic mass isotope effects but rather by nuclear magnetic moment and/or magnetic spin isotope effects

  6. Advertising Content

    OpenAIRE

    Simon P. Anderson; Régis Renault

    2002-01-01

    Empirical evidence suggests that most advertisements contain little direct informa- tion. Many do not mention prices. We analyze a firm'ss choice of advertising content and the information disclosed to consumers. A firm advertises only product informa- tion, price information, or both; and prefers to convey only limited product information if possible. Extending the "persuasion" game, we show that quality information takes precedence over price information and horizontal product information.T...

  7. Poly(ester amide-Poly(ethylene oxide Graft Copolymers: Towards Micellar Drug Delivery Vehicles

    Directory of Open Access Journals (Sweden)

    Gregory J. Zilinskas

    2012-01-01

    Full Text Available Micelles formed from amphiphilic copolymers are promising materials for the delivery of drug molecules, potentially leading to enhanced biological properties and efficacy. In this work, new poly(ester amide-poly(ethylene oxide (PEA-PEO graft copolymers were synthesized and their assembly into micelles in aqueous solution was investigated. It was possible to tune the sizes of the micelles by varying the PEO content of the polymers and the method of micelle preparation. Under optimized conditions, it was possible to obtain micelles with diameters less than 100 nm as measured by dynamic light scattering and transmission electron microscopy. These micelles were demonstrated to encapsulate and release a model drug, Nile Red, and were nontoxic to HeLa cells as measured by an MTT assay. Overall, the properties of these micelles suggest that they are promising new materials for drug delivery systems.

  8. Ring opening metathesis polymerization-derived block copolymers bearing chelating ligands: synthesis, metal immobilization and use in hydroformylation under micellar conditions

    Directory of Open Access Journals (Sweden)

    Gajanan M. Pawar

    2010-03-01

    Full Text Available Norborn-5-ene-(N,N-dipyrid-2-ylcarbamide (M1 was copolymerized with exo,exo-[2-(3-ethoxycarbonyl-7-oxabicyclo[2.2.1]hept-5-en-2-carbonyloxyethyl]trimethylammonium iodide (M2 using the Schrock catalyst Mo(N-2,6-Me2-C6H3(CHCMe2Ph(OCMe(CF322 [Mo] to yield poly(M1-b-M2. In water, poly(M1-b-M2 forms micelles with a critical micelle-forming concentration (cmc of 2.8 × 10−6 mol L−1; Reaction of poly(M1-b-M2 with [Rh(CODCl]2 (COD = cycloocta-1,5-diene yields the Rh(I-loaded block copolymer poly(M1-b-M2-Rh containing 18 mg of Rh(I/g of block copolymer with a cmc of 2.2 × 10−6 mol L−1. The Rh-loaded polymer was used for the hydroformylation of 1-octene under micellar conditions. The data obtained were compared to those obtained with a monomeric analogue, i.e. CH3CON(Py2RhCl(COD (C1, Py = 2-pyridyl. Using the polymer-supported catalyst under micellar conditions, a significant increase in selectivity, i.e. an increase in the n:iso ratio was accomplished, which could be further enhanced by the addition of excess ligand, e.g., triphenylphosphite. Special features of the micellar catalytic set up are discussed.

  9. Tuning the probe location on zwitterionic micellar system with variation of pH and addition of surfactants with different alkyl chains: solvent and rotational relaxation studies.

    Science.gov (United States)

    Banerjee, Chiranjib; Mandal, Sarthak; Ghosh, Surajit; Rao, Vishal Govind; Sarkar, Nilmoni

    2012-09-13

    In this manuscript, we have modulated the location of an anionic probe, Coumarin-343 (C-343) in a zwitterionic (N-hexadecyl-N,N-dimethylammonio-1-propanesulfonate (SB-16)) micellar system by three different approaches. The effect of addition of the surfactant sodium dodecyl sulfate (SDS) and the room temperature ionic liquid (RTIL), 1-ethyl-3-methylimidazolium octylsulfate (EmimOs) and N,N-dimethylethanol hexanoate (DAH), to the micellar solution has been studied. The effect of pH variation has been studied as well using solvent and rotational measurements. Migration of the anionic probe, C-343, from the palisade layer of SB-16 micelle to the bulk water has been observed to varying extents with the addition of SDS and EmimOs. The effect is much more pronounced in the presence of SDS and can be ascribed to the presence of the long alkyl (dodecyl) chain on SDS which can easily orient itself and fuse inside the SB-16 micelle and facilitate the observed migration of the probe molecule. This phenomenon is confirmed by faster solvation and rotational relaxation of the investigated probe molecule. The analogous fusion process is difficult in case of EmimOs and DAH because of their comparatively smaller alkyl (octyl and hexanoate) chain. However, the direction of C-343 migration is reversed with the decrease of pH of the SB-16 micellar medium. An increase in the average solvation and rotational relaxation time of the probe in acidic medium has been observed. Since experimental conditions are maintained such that the probe molecules and the zwitterionic SB-16 micelles remain oppositely charged, the observed results can be attributed to the increased electrostatic interaction (attractive) between them. Temperature dependent study also supports this finding.

  10. Application of Fluorescence Emission for Characterization of Albendazole and Ricobendazole Micellar Systems: Elucidation of the Molecular Mechanism of Drug Solubilization Process.

    Science.gov (United States)

    Priotti, Josefina; Leonardi, Darío; Pico, Guillermo; Lamas, María C

    2018-04-01

    Albendazole (ABZ) and ricobendazole (RBZ) are referred to as class II compounds in the Biopharmaceutical Classification System. These drugs exhibit poor solubility, which profoundly affects their oral bioavailability. Micellar systems are excellent pharmaceutical tools to enhance solubilization and absorption of poorly soluble compounds. Polysorbate 80 (P80), poloxamer 407 (P407), sodium cholate (Na-C), and sodium deoxycholate (Na-DC) have been selected as surfactants to study the solubilization process of these drugs. Fluorescence emission was applied in order to obtain surfactant/fluorophore (S/F) ratio, critical micellar concentration, protection efficiency of micelles, and thermodynamic parameters. Systems were characterized by their size and zeta potential. A blue shift from 350 to 345 nm was observed when ABZ was included in P80, Na-DC, and Na-C micelles, while RBZ showed a slight change in the fluorescence band. P80 showed a significant solubilization capacity: S/F values were 688 for ABZ at pH 4 and 656 for RBZ at pH 6. Additionally, P80 micellar systems presented the smallest size (10 nm) and their size was not affected by pH change. S/F ratio for bile salts was tenfold higher than for the other surfactants. Quenching plots were linear and their constant values (2.17/M for ABZ and 2.29/M for RBZ) decreased with the addition of the surfactants, indicating a protective effect of the micelles. Na-DC showed better protective efficacy for ABZ and RBZ than the other surfactants (constant values 0.54 and 1.57/M, respectively), showing the drug inclusion into the micelles. Entropic parameters were negative in agreement with micelle formation.

  11. A micellar model system for the role of zeaxanthin in the non-photochemical quenching process of photosynthesis--chlorophyll fluorescence quenching by the xanthophylls.

    Science.gov (United States)

    Avital, Shlomo; Brumfeld, Vlad; Malkin, Shmuel

    2006-07-01

    To get an insight to the mechanism of the zeaxanthin-dependent non-photochemical quenching in photosystem II of photosynthesis, we probed the interaction of some xanthophylls with excited chlorophyll-a by trapping both pigments in micelles of triton X-100. Optimal distribution of pigments among micelles was obtained by proper control of the micelle concentration, using formamide in the reaction mixture, which varies the micellar aggregation number over three orders of magnitude. The optimal reaction mixture was obtained around 40% (v/v) formamide in 0.2-0.4% (v/v) triton X-100 in water. Zeaxanthin in the micellar solution exhibited initially absorption and circular dichroism spectral features corresponding to a J-type aggregate. The spectrum was transformed over time (half-time values vary-an average characteristic figure is roughly 20 min) to give features representing an H-type aggregate. The isosbestic point in the series of spectral curves favors the supposition of a rather simple reaction between two pure J and H-types dimeric species. Violaxanthin exhibited immediately stable spectral features corresponding to a mixture of J-type and more predominately H-type dimers. Lutein, neoxanthin and beta-carotene did not show any aggregated spectral forms in micelles. The spectral features in micelles were compared to spectra in aqueous acetone, where the assignment to various aggregated types was established previously. The specific tendency of zeaxanthin to form the J-type dimer (or aggregate) could be important for its function in photosynthesis. The abilities of five carotenoids (zeaxanthin, violaxanthin, lutein, neoxanthin and beta-carotene) to quench chlorophyll-a fluorescence were compared. Zeaxanthin, in its two micellar dimeric forms, and beta-carotene were comparable good quenchers of chlorophyll-a fluorescence. Violaxanthin was a much weaker quencher, if at all. Lutein and neoxanthin rather enhanced the fluorescence. The implications to non

  12. Colloidal chirality in wormlike micellar systems exclusively originated from achiral species: Role of secondary assembly and stimulus responsivity.

    Science.gov (United States)

    Zhao, Wenrong; Hao, Jingcheng

    2016-09-15

    Colloidal chirality in wormlike micellar systems exclusively originated from achiral species and discussion of the role of secondary assembly of fiber-like aggregates in chirality generation were presented in this paper. Herein, formation of colloidal wormlike micelles for the first time incorporated chirality and redox-responsiveness into one design via noncovalent interaction. A dual-stimuli-responsive gel of wormlike micelles which were designed by employing a dual-responsive cationic surfactant (FTMA) and a strong gelator (AzoNa4) and regulated by redox reaction and host-guest inclusion is presented. Both the redox and host-guest interaction play an important role in regulating the viscosity and supramolecular chirality of gels of the wormlike micelles. The supramolecular chirality and viscosity of the wormlike micelle gels were switched reversibly by exerting chemical redox onto the ferrocenyl groups. For the amphiphile FTMA containing redox-active ferrocenyl group, reversible control of the oxidation state of ferrocenyl groups leads to the charge and hydrophobicity changes of FTMA, therefore change its self-assembly behavior. Of equal interest, β-CD successfully detached the wormlike micelles via the recognition-inclusion behavior with FTMA and invalidate the H-bond and hydrophobic interaction between FTMA and AzoH4. This designed system provides a new strategy to tune the supramolecular chirality of colloidal aggregates and explore the specific packing mode detail within the micelles or the secondary assembly of the inter-micelles. We anticipate this dual-responsive H-bond-directed chiral gel switch could propose a new strategy when researchers designing new, multi-responsive functional gel materials. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Versatility of non-native forms of human cytochrome c: pH and micellar concentration dependence.

    Science.gov (United States)

    Simon, Matthieu; Metzinger-Le Meuth, Valérie; Chevance, Soizic; Delalande, Olivier; Bondon, Arnaud

    2013-01-01

    In addition to its electron transfer activity, cytochrome c is now known to trigger apoptosis via peroxidase activity. This new function is related to a structural modification of the cytochrome upon association with anionic lipids, particularly cardiolipin present in the mitochondrial membrane. However, the exact nature of the non-native state induced by this interaction remains an active subject of debate. In this work, using human cytochromes c (native and two single-histidine mutants and the corresponding double mutant) and micelles as a hydrophobic medium, we succeeded, through UV-visible spectroscopy, circular dichroism spectroscopy and NMR spectroscopy, in fully characterizing the nature of the sixth ligand replacing the native methionine. Furthermore, careful pH titrations permitted the identification of the amino acids involved in the iron binding over a range of pH values. Replacement of the methionine by lysine was only observed at pH above 8.5, whereas histidine binding is dependent on both pH and micelle concentration. The pH variation range for histidine protonation is relatively narrow and is consistent with the mitochondrial intermembrane pH changes occurring during apoptosis. These results allow us to rule out lysine as the sixth ligand at pH values close to neutrality and reinforce the role of histidines (preferentially His33 vs. His26) as the main candidate to replace methionine in the non-native cytochrome c. Finally, on the basis of these results and molecular dynamics simulations, we propose a 3D model for non-native cytochrome c in a micellar environment.

  14. Influence of salts on the coexistence curve and protein partitioning in nonionic aqueous two-phase micellar systems

    Directory of Open Access Journals (Sweden)

    A. M. Lopes

    2014-12-01

    Full Text Available Aqueous two-phase micellar systems (ATPMS can be exploited in separation science for the extraction/purification of desired biomolecules. Prior to phase separation the surfactant solution reaches a cloud point temperature, which is influenced by the presence of electrolytes. In this work, we provide an investigation on the cloud point behavior of the nonionic surfactant C10E4 in the presence of NaCl, Li2SO4 and KI. We also investigated the salts' influence on a model protein partitioning. NaCl and Li2SO4 promoted a depression of the cloud point. The order of salts and the concentration that decreased the cloud point was: Li2SO4 0.5 M > NaCl 0.5 M ≈ Li2SO4 0.2 M. On the other hand, 0.5 M KI dislocated the curve to higher cloud point values. For our model protein, glucose-6-phosphate dehydrogenase (G6PD, partitioning experiments with 0.5 M NaCl or 0.2 M Li2SO4 at 13.85 ºC showed similar results, with K G6PD ~ 0.46. The lowest partition coefficient was obtained in the presence of 0.5 M KI (K G6PD = 0.12, with major recovery of the enzyme in the micelle-dilute phase (%Recovery = 90%. Our results show that choosing the correct salt to add to ATPMS may be useful to attain the desired partitioning conditions at more extreme temperatures. Furthermore, this system can be effective to separate a target biomolecule from fermented broth contaminants.

  15. Micellar HPLC and derivative spectrophotometric methods for the simultaneous determination of fluconazole and tinidazole in pharmaceuticals and biological fluids.

    Science.gov (United States)

    Belal, F; Sharaf El-Din, M K; Eid, M I; El-Gamal, R M

    2014-04-01

    Micellar high-performance liquid chromatography (HPLC) and first-derivative ultraviolet spectrophotometry were used to simultaneously determine fluconazole (FLZ) and tinidazole (TNZ) in combined pharmaceutical dosage forms. The derivative procedure is based on the linear relationship between the drug concentration and the first derivative amplitudes at 220 and 288 nm for FLZ and TNZ, respectively. The calibration graphs were linear in the range of 1.5-9.0 µg/mL for FLZ and 10.0-60.0 µg/mL for TNZ. Furthermore, an HPLC procedure with ultraviolet detection at 210 nm was developed. For the HPLC procedure, good chromatographic separation was achieved using an ODS C18 column (250 × 4.6 mm i.d.). The mobile phase containing 0.15M sodium dodecyl sulphate, 0.3% triethylamine and 12% n-propanol in 0.02M orthophosphoric acid at pH 5.5 was pumped at a flow rate of 1 mL/min. Indapamide was used as an internal standard. The method showed good linearity over the concentration ranges of 1.5-30.0 and 10.0-200.0 µg/mL, with limits of detection of 0.36 and 2.70 µg/mL and limits of quantification of 1.1 and 8.2 µg/mL for FLZ and TNZ, respectively. The suggested methods were successfully applied for the simultaneous analysis of the drugs in their laboratory prepared mixture, co-formulated tablet and single dosage forms. Moreover the second method was also extended to the determination of the drugs in biological fluids.

  16. Study to determine the technical and economic feasibility of reclaiming chemicals used in micellar polymer and low tension surfactant flooding. Final report. [Ultrafiltration membranes and reverse osmosis membranes

    Energy Technology Data Exchange (ETDEWEB)

    Stephens, R.H.; Himmelblau, A.; Donnelly, R.G.

    1978-02-01

    Energy Resources Company has developed a technology for use with enhanced oil recovery to achieve emulsion breaking and surfactant recovery. By using ultrafiltration membranes, the Energy Resources Company process can dewater an oil-in-water type emulsion expected from enhanced oil recovery projects to the point where the emulsion can be inverted and treated using conventional emulsion-treating equipment. By using a tight ultrafiltration membrane or a reverse osmosis membrane, the Energy Resources Company process is capable of recovering chemicals such as surfactants used in micellar polymer flooding.

  17. Liquid-liquid extraction and separation of VIII group elements, especially ruthenium, by synergic combinations or aromatic polyimines and micellar cationic exchangers

    International Nuclear Information System (INIS)

    Vitart, X.

    1991-01-01

    This thesis aims to characterize and to quantify the chemical equilibria involved in d-elements liquid-liquid extraction systems, especially elements belonging to the VIII group (Fe, Ni, Co, Ru, Rh, Pd, Pt). These systems are composed of synergic combination of aromatic polyimines and micellar cationic exchangers. Substitutions are first performed in aqueous acidic media by aromatic polyimines; then extractions are operated using micellic canionic exchangers. Chemical equilibria, selectivity effects, especially those due to ion-pair formations, kinetics, extractant behaviour are analysed and quantified [fr

  18. Novel Schiff base (DBDDP) selective detection of Fe (III): Dispersed in aqueous solution and encapsulated in silica cross-linked micellar nanoparticles in living cell.

    Science.gov (United States)

    Gai, Fangyuan; Yin, Li; Fan, Mengmeng; Li, Ling; Grahn, Johnny; Ao, Yuhui; Yang, Xudong; Wu, Xuming; Liu, Yunling; Huo, Qisheng

    2018-03-15

    This work demonstrated the synthesis of (4E)-4-(4-(diphenylamino)benzylideneamino)-1,2-dihydro-1,5- dimethyl-2-phenylpyrazol-3-one (DBDDP) for Fe (III) detection in aqueous media and in the core of silica cross-linked micellar nanoparticles in living cells. The free DBDDP performed fluorescence enhancement due to Fe (III)-promoted hydrolysis in a mixed aqueous solution, while the DBDDP-doped silica cross-linked micellar nanoparticles (DBDDP-SCMNPs) performed an electron-transfer based fluorescence quenching of Fe (III) in living cells. The quenching fluorescence of DBDDP-SCMNPs and the concentration of Fe (III) exhibited a linear correlation, which was in accordance with the Stern-Volmer equation. Moreover, DBDDP-SCMNPs showed a low limit of detection (LOD) of 0.1 ppm and an excellent selectivity against other metal ions. Due to the good solubility and biocompatibility, DBDDP-SCMNPs could be applied as fluorescence quenching nanosensors in living cells. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Micellar effect on the sensitivity of spectrophotometric Mo(VI) determination based on the formation of gallic acid complex providing evidence for the polyoxoanion structure of molybdate ions

    International Nuclear Information System (INIS)

    Tascioglu, Senay; Sendil, Olcay; Beyreli, Sivekar

    2007-01-01

    In this study effects of anionic (sodium dodecyl sulfate, SDS), cationic (cetyltrimethylammonium bromide, CTAB) and nonionic (Triton X-100, TX100) micelles on the sensitivity of spectrophotometric molybdenum(VI) (Mo) determination based on the formation of a binary complex with gallic acid (GA) were investigated. Micellar CTAB was found to enhance the formation of Mo-GA complex. SDS micelles exerted an inhibitory effect while TX100 micelles had no effect on the complex formation. By the optimization of experimental conditions, the determination limit of the method suggested in the literature was lowered from 5.2 x 10 -5 to 4.6 x 10 -6 and to 5.7 x 10 -7 M, in the absence and presence of CTAB, respectively. The mechanism of the effect of CTAB was investigated by spectrophotometric titrations and it was concluded that CTAB did not form a ternary complex with Mo and GA. The stoichiometry of the complex, deduced from the results of spectrophotometric titrations, provided evidence for the formation of para-Mo 7 O 4 6- polyanions at pH 4.5, indicating to the formation of a charge transfer complex between these ions and GA in micellar medium

  20. Semi-empirical spectrophotometric (SESp) method for the indirect determination of the ratio of cationic micellar binding constants of counterions X⁻ and Br⁻(K(X)/K(Br)).

    Science.gov (United States)

    Khan, Mohammad Niyaz; Yusof, Nor Saadah Mohd; Razak, Norazizah Abdul

    2013-01-01

    The semi-empirical spectrophotometric (SESp) method, for the indirect determination of ion exchange constants (K(X)(Br)) of ion exchange processes occurring between counterions (X⁻ and Br⁻) at the cationic micellar surface, is described in this article. The method uses an anionic spectrophotometric probe molecule, N-(2-methoxyphenyl)phthalamate ion (1⁻), which measures the effects of varying concentrations of inert inorganic or organic salt (Na(v)X, v = 1, 2) on absorbance, (A(ob)) at 310 nm, of samples containing constant concentrations of 1⁻, NaOH and cationic micelles. The observed data fit satisfactorily to an empirical equation which gives the values of two empirical constants. These empirical constants lead to the determination of K(X)(Br) (= K(X)/K(Br) with K(X) and K(Br) representing cationic micellar binding constants of counterions X and Br⁻). This method gives values of K(X)(Br) for both moderately hydrophobic and hydrophilic X⁻. The values of K(X)(Br), obtained by using this method, are comparable with the corresponding values of K(X)(Br), obtained by the use of semi-empirical kinetic (SEK) method, for different moderately hydrophobic X. The values of K(X)(Br) for X = Cl⁻ and 2,6-Cl₂C6H₃CO₂⁻, obtained by the use of SESp and SEK methods, are similar to those obtained by the use of other different conventional methods.

  1. Micellar effect on metal-ligand complexes of Co(II, Ni(II, Cu(II and Zn(II with citric acid

    Directory of Open Access Journals (Sweden)

    Nageswara Rao Gollapalli

    2009-12-01

    Full Text Available Chemical speciation of citric acid complexes of Co(II, Ni(II, Cu(II and Zn(II was investigated pH-metrically in 0.0-2.5% anionic, cationic and neutral micellar media. The primary alkalimetric data were pruned with SCPHD program. The existence of different binary species was established from modeling studies using the computer program MINIQUAD75. Alkalimetric titrations were carried out in different relative concentrations (M:L:X = 1:2:5, 1:3:5, 1:5:3 of metal (M to citric acid. The selection of best chemical models was based on statistical parameters and residual analysis. The species detected were MLH, ML2, ML2H and ML2H2. The trend in variation of stability constants with change in mole fraction of the medium is explained on the basis of electrostatic and non-electrostatic forces. Distributions of the species with pH at different compositions of micellar media are also presented.

  2. Thermo-acoustical analysis of sodium dodecyl sulfate: Fluconazole (antifungal drug) based micellar system in hydro-ethanol solutions for potential drug topical application

    International Nuclear Information System (INIS)

    Bhardwaj, Tarun; Bhardwaj, Varun; Sharma, Kundan; Gupta, Abhishek; Cameotra, Swaranjit Singh; Sharma, Poonam

    2014-01-01

    Highlights: • The mixed micellar system was analyzed for sodium dodecyl sulfate and fluconazole. • Early micellization was found with CMC shift towards lower surfactant concentration. • Negative ΔG m o values suggested that the micelle formation is spontaneous and feasible. • Thermo-acoustical parameters revealed the existence of intermolecular interactions within the molecules. - Abstract: Micellar systems hold excellent drug delivery applications due to their capability to solubilize a large number of hydrophobic and hydrophilic molecules. In this present work, the mixed micelle formation between the anionic surfactant sodium dodecyl sulfate (SDS) and the ‘Azole’ derivative antifungal drug fluconazole (FLZ) have been studied at four temperatures in different hydro-ethanolic solutions. The critical micelle concentration (CMC) was determined by specific conductance techniques and the experimental data was used to calculate several useful thermodynamic parameters, like standard free energy, enthalpy and entropy of micelle formation. Early micellization was found with critical micelle concentration shifting towards lower concentration (CMC) than the standard concentration of SDS in water at 25 °C suggesting that drug and the solvent system facilitates the micellization process. In addition, the transport properties were examined by employing controlled approaches likely, apparent molar volume (ϕ v ), apparent molar adiabatic compression (ϕ k ), and isentropic compression (κ s ) of SDS in presence of FLZ. These parameters revealed the existence of intermolecular interactions within the molecules. Therefore, this study would cast light on utilizing surfactant immobilized FLZ system for better topical biological action

  3. Redox behavior and optical response of nanostructured poly(3,4-ethylenedioxythiophene) films grown in a camphorsulfonic acid based micellar solution

    International Nuclear Information System (INIS)

    Bhandari, Shweta; Deepa, M.; Singh, S.; Gupta, Govind; Kant, Rama

    2008-01-01

    Poly(3,4-ethylenedioxythiophene) (PEDOT) films have been electropolymerized from an aqueous micellar solution comprising camphorsulfonic acid (CSA), lithium trifluoromethanesulfonate (LiCF 3 SO 3 ) and EDOT. The inclusion of the dopants CS - and CF 3 SO 3 - in the polymer structure and an unusually high doping level of 0.54 have been ascertained by the X-ray photoelectron spectroscopy. Transmission electron microscopy and atomic force microscopy studies show that the micellar effect of CSA leads to a morphology wherein polymer particles link together to form elongated shapes and also endows the film with a surface roughness of 25-30 nm. These nanostructures permit a facile intercalation-deintercalation of anions in the film during redox cycling. Electrochemical impedance spectroscopy show that the charge transfer phenomenon at the PEDOT-electrolyte interface is dominant in the high frequency region and diffusion controlled ionic movement prevails in the low frequency regime. The use of these films as potential cathodes in electrochromic windows is rationalized not only on the basis of their high scalability and ease of processing but also due to their large coloration efficiency (123 cm 2 C -1 ) and transmission modulation (50%) at a photopic wavelength of 550 nm. But further improvement in color-bleach kinetics and reproducibility of redox behavior is desirable to broaden their spectrum of utility

  4. Impact of Surface Active Ionic Liquids on the Cloud Points of Nonionic Surfactants and the Formation of Aqueous Micellar Two-Phase Systems.

    Science.gov (United States)

    Vicente, Filipa A; Cardoso, Inês S; Sintra, Tânia E; Lemus, Jesus; Marques, Eduardo F; Ventura, Sónia P M; Coutinho, João A P

    2017-09-21

    Aqueous micellar two-phase systems (AMTPS) hold a large potential for cloud point extraction of biomolecules but are yet poorly studied and characterized, with few phase diagrams reported for these systems, hence limiting their use in extraction processes. This work reports a systematic investigation of the effect of different surface-active ionic liquids (SAILs)-covering a wide range of molecular properties-upon the clouding behavior of three nonionic Tergitol surfactants. Two different effects of the SAILs on the cloud points and mixed micelle size have been observed: ILs with a more hydrophilic character and lower critical packing parameter (CPP formation of smaller micelles and concomitantly increase the cloud points; in contrast, ILs with a more hydrophobic character and higher CPP (CPP ≥ 1) induce significant micellar growth and a decrease in the cloud points. The latter effect is particularly interesting and unusual for it was accepted that cloud point reduction is only induced by inorganic salts. The effects of nonionic surfactant concentration, SAIL concentration, pH, and micelle ζ potential are also studied and rationalized.

  5. Selective micellar electrokinetic chromatographic method for simultaneous determination of some pharmaceutical binary mixtures containing non-steroidal anti-inflammatory drugs

    Directory of Open Access Journals (Sweden)

    Michael E. El-Kommos

    2013-02-01

    Full Text Available A simple and selective micellar electrokinetic chromatographic (MEKC method has been developed for the analysis of five pharmaceutical binary mixtures containing three non-steroidal anti-inflammatory drugs (NSAIDs. The investigated mixtures were Ibuprofen (IP–Paracetamol (PC, Ibuprofen (IP–Chlorzoxazone (CZ, Ibuprofen (IP–Methocarbamol (MC, Ketoprofen (KP–Chlorzoxazone (CZ and Diclofenac sodium (DS–Lidocaine hydrochloride (LC. The separation was run for all mixtures using borate buffer (20 mM, pH 9 containing 15% (v/v methanol and 100 mM sodium dodecyl sulphate (SDS at 15 kV and the components were detected at 214 nm. Different factors affecting the electrophoretic mobility of the seven investigated drugs were studied and optimized. The method was validated according to international conference of harmonization (ICH guidelines and United States pharmacopoeia (USP. The method was applied to the analysis of five pharmaceutical binary mixtures in their dosage forms. The results were compared with other reported high performance liquid chromatographic methods and no significant differences were observed. Keywords: Capillary electrophoresis, Micellar electrokinetic chromatographic method, Non-steroidal anti-inflammatory drugs, Pharmaceutical binary mixtures, Pharmaceutical analysis

  6. A review on development of analytical methods to determine monitorable drugs in serum and urine by micellar liquid chromatography using direct injection.

    Science.gov (United States)

    Esteve-Romero, Josep; Albiol-Chiva, Jaume; Peris-Vicente, Juan

    2016-07-05

    Therapeutic drug monitoring is a common practice in clinical studies. It requires the quantification of drugs in biological fluids. Micellar liquid chromatography (MLC), a well-established branch of Reverse Phase-High Performance Liquid Chromatography (RP-HPLC), has been proven by many researchers as a useful tool for the analysis of these matrices. This review presents several analytical methods, taken from the literature, devoted to the determination of several monitorable drugs in serum and urine by micellar liquid chromatography. The studied groups are: anticonvulsants, antiarrhythmics, tricyclic antidepressants, selective serotonin reuptake inhibitors, analgesics and bronchodilators. We detail the optimization strategy of the sample preparation and the main chromatographic conditions, such as the type of column, mobile phase composition (surfactant, organic solvent and pH), and detection. The finally selected experimental parameters, the validation, and some applications have also been described. In addition, their performances and advantages have been discussed. The main ones were the possibility of direct injection, and the efficient chromatographic elution, in spite of the complexity of the biological fluids. For each substance, the measured concentrations were accurate and precise at their respective therapeutic range. It was found that the MLC-procedures are fast, simple, inexpensive, ecofriendly, safe, selective, enough sensitive and reliable. Therefore, they represent an excellent alternative for the determination of drugs in serum and urine for monitoring purposes. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Nanodrug-enhanced radiofrequency tumor ablation: effect of micellar or liposomal carrier on drug delivery and treatment efficacy.

    Directory of Open Access Journals (Sweden)

    Marwan Moussa

    Full Text Available To determine the effect of different drug-loaded nanocarriers (micelles and liposomes on delivery and treatment efficacy for radiofrequency ablation (RFA combined with nanodrugs.Fischer 344 rats were used (n = 196. First, single subcutaneous R3230 tumors or normal liver underwent RFA followed by immediate administration of i.v. fluorescent beads (20, 100, and 500 nm, with fluorescent intensity measured at 4-24 hr. Next, to study carrier type on drug efficiency, RFA was combined with micellar (20 nm or liposomal (100 nm preparations of doxorubicin (Dox; targeting HIF-1α or quercetin (Qu; targeting HSP70. Animals received RFA alone, RFA with Lipo-Dox or Mic-Dox (1 mg i.v., 15 min post-RFA, and RFA with Lipo-Qu or Mic-Qu given 24 hr pre- or 15 min post-RFA (0.3 mg i.v.. Tumor coagulation and HIF-1α or HSP70 expression were assessed 24 hr post-RFA. Third, the effect of RFA combined with i.v. Lipo-Dox, Mic-Dox, Lipo-Qu, or Mic-Qu (15 min post-RFA compared to RFA alone on tumor growth and animal endpoint survival was evaluated. Finally, drug uptake was compared between RFA/Lipo-Dox and RFA/Mic-Dox at 4-72 hr.Smaller 20 nm beads had greater deposition and deeper tissue penetration in both tumor (100 nm/500 nm and liver (100 nm (p<0.05. Mic-Dox and Mic-Qu suppressed periablational HIF-1α or HSP70 rim thickness more than liposomal preparations (p<0.05. RFA/Mic-Dox had greater early (4 hr intratumoral doxorubicin, but RFA/Lipo-Dox had progressively higher intratumoral doxorubicin at 24-72 hr post-RFA (p<0.04. No difference in tumor growth and survival was seen between RFA/Lipo-Qu and RFA/Mic-Qu. Yet, RFA/Lipo-Dox led to greater animal endpoint survival compared to RFA/Mic-Dox (p<0.03.With RF ablation, smaller particle micelles have superior penetration and more effective local molecular modulation. However, larger long-circulating liposomal carriers can result in greater intratumoral drug accumulation over time and reduced tumor growth. Accordingly

  8. An in vivo mechanism for the reduced peripheral neurotoxicity of NK105: a paclitaxel-incorporating polymeric micellar nanoparticle formulation

    Directory of Open Access Journals (Sweden)

    Nakamura I

    2017-02-01

    Full Text Available Iwao Nakamura, Eiji Ichimura, Rika Goda, Hitomi Hayashi, Hiroko Mashiba, Daichi Nagai, Hirofumi Yokoyama, Takeshi Onda, Akira Masuda Nanomedicine Group, Pharmaceutical Research Laboratories, Nippon Kayaku Co., Ltd., Tokyo, Japan Abstract: In our previous rodent studies, the paclitaxel (PTX-incorporating polymeric micellar nanoparticle formulation NK105 had showed significantly stronger antitumor effects and reduced peripheral neurotoxicity than PTX dissolved in Cremophor® EL and ethanol (PTX/CRE. Thus, to elucidate the mechanisms underlying reduced peripheral neurotoxicity due to NK105, we performed pharmacokinetic analyses of NK105 and PTX/CRE in rats. Among neural tissues, the highest PTX concentrations were found in the dorsal root ganglion (DRG. Moreover, exposure of DRG to PTX (Cmax_PTX and AUC0-inf._PTX in the NK105 group was almost half that in the PTX/CRE group, whereas exposure of sciatic and sural nerves was greater in the NK105 group than in the PTX/CRE group. In histopathological analyses, damage to DRG and both peripheral nerves was less in the NK105 group than in the PTX/CRE group. The consistency of these pharmacokinetic and histopathological data suggests that high levels of PTX in the DRG play an important role in the induction of peripheral neurotoxicity, and reduced distribution of PTX to the DRG of NK105-treated rats limits the ensuing peripheral neurotoxicity. In further analyses of PTX distribution to the DRG, Evans blue (Eb was injected with BODIPY®-labeled NK105 into rats, and Eb fluorescence was observed only in the DRG. Following injection, most Eb dye bound to albumin particles of ~8 nm and had penetrated the DRG. In contrast, BODIPY®–NK105 particles of ~90 nm were not found in the DRG, suggesting differential penetration based on particle size. Because PTX also circulates as PTX–albumin particles of ~8 nm following injection of PTX/CRE, reduced peripheral neurotoxicity of NK105 may reflect exclusion from the

  9. Treatment of aqueous outflows by complexation in micellar media and precipitation with a sol-gel process

    International Nuclear Information System (INIS)

    Lavaud, Cyril

    2013-01-01

    Being able to deal with aqueous outflows from treatment sites in the Hague is a major environmental issue. These outflows are contaminated with organic substances and elements with residual radioactivity. This work deals with the development and optimization of the process of de-polluting, and we aim at removing all pollution from the outflow, and produce a final waste compatible with traditional conditioning matrices in the nuclear area. The separation process consists of two steps: dissolving the pollution in the surfactants micelles, and precipitating a mineral phase via sol-gel transition. Within this thesis, only pollution originating from radionuclides is studied. During the first step, our strategy is to use complexing molecules able to interact with ions and to form mainly solvable complexes at the core of surfactant micelles. Thereafter, the second step consisted to add silica precursor which, after hydrolyse and polycondensation, makes it possible to aggregate those micelles that contain complexes together, and to form a silica phase which precipitates in an in-situ fashion. The goal to de-pollute the outflow was achieved, and the final waste thus produced is a silica powder that contains the micelles and the pollution which, after calcination, is compatible with conditioning matrices such as glass or concrete. A reference system for which the separation process is optimal was defined throughout various studies. This system contains a non-ionic surfactant (P123), an ion that surrogates radionuclides (neodymium), a complexing agent (HDEHP) and a silica precursor (TEOS). Hence, this system was further studied in order to broaden the application scope of the separation process, as well as to understand the mechanisms involved, during the complexation of the ions and the micellar solubilization and during the formation of the silica powder. This study was performed using diffusion, imaging and spectrometry techniques.To conclude, the alternative de

  10. Supramolecular micellar nanoaggregates based on a novel chitosan/vitamin E succinate copolymer for paclitaxel selective delivery

    Directory of Open Access Journals (Sweden)

    Lian H

    2011-12-01

    experiments, conducted by confocal laser scanning microscopy, showed an enhanced cellular uptake efficiency of the CS-VES micelles in MCF-7 cells compared with Taxol. The PTX-micelles exhibited a comparable but delayed cytotoxic effect compared with Taxol against MCF-7 cells, due to the sustained-release characteristics of the nanomicelles. More interestingly, blank nanomicelles based on CS-VES copolymer demonstrated significant cytotoxicity against MCF-7 cells.Conclusion: The supramolecular micellar aggregates based on CS-VES copolymer is a promising nanocarrier and efficacy enhancer when used as an anticancer drug-delivery system.Keywords: nanomicelles, cellular uptake, cytotoxicity

  11. On-line identification of lysergic acid diethylamide (LSD) in tablets using a combination of a sweeping technique and micellar electrokinetic chromatography/77 K fluorescence spectroscopy.

    Science.gov (United States)

    Fang, Ching; Liu, Ju-Tsung; Lin, Cheng-Huang

    2003-03-01

    This work describes a novel method for the accurate determination of lysergic acid diethylamide (LSD) in tablets. A technique involving sweeping-micellar electrokinetic chromatography (MEKC) was used for the initial on-line concentration and separation, after which a cryogenic molecular fluorescence experiment was performed at 77 K. Using this approach, not only the separation of LSD from the tablet extract was achieved, but on-line spectra were readily distinguishable and could be unambiguously assigned. The results are in agreement with analyses by gas chromatography-mass spectrometry (GC-MS). Thus, this method, which was found to be accurate, sensitive and rapid, has the potential for use as a reliable complementary method to GC-MS in such analyses.

  12. Fluorescence resonance energy transfer between perylene and riboflavin in micellar solution and analytical application on determination of vitamin B{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Bhattar, S.L.; Kolekar, G.B. [Fluorescence Spectroscopy Research Laboratory, Department of Chemistry, Shivaji University, Kolhapur 416 004, Maharashtra (India); Patil, S.R. [Fluorescence Spectroscopy Research Laboratory, Department of Chemistry, Shivaji University, Kolhapur 416 004, Maharashtra (India)], E-mail: srp_fsl@rediffmail.com

    2008-03-15

    Fluorescence resonance energy transfer (FRET) between perylene and riboflavin is studied in micellar solution of sodium dodecyl sulfate. The fluorescence of perylene is quenched by riboflavin and quenching is in accordance with Stern-Volmer relation. The efficiency of energy transfer is found to depend on the concentration of riboflavin. The value of critical energy transfer distance (R{sub 0}) calculated by using Foster relation is 32.13 A, and as it is less than 50 A, it indicates efficient energy transfer in the present system. The analytical relation was established between extent of sensitization and concentration of riboflavin, which helped to estimate vitamin B{sub 2} directly from pharmaceutical tablets.

  13. Separation of very hydrophobic analytes by micellar electrokinetic chromatography IV. Modeling of the effective electrophoretic mobility from carbon number equivalents and octanol-water partition coefficients.

    Science.gov (United States)

    Huhn, Carolin; Pyell, Ute

    2008-07-11

    It is investigated whether those relationships derived within an optimization scheme developed previously to optimize separations in micellar electrokinetic chromatography can be used to model effective electrophoretic mobilities of analytes strongly differing in their properties (polarity and type of interaction with the pseudostationary phase). The modeling is based on two parameter sets: (i) carbon number equivalents or octanol-water partition coefficients as analyte descriptors and (ii) four coefficients describing properties of the separation electrolyte (based on retention data for a homologous series of alkyl phenyl ketones used as reference analytes). The applicability of the proposed model is validated comparing experimental and calculated effective electrophoretic mobilities. The results demonstrate that the model can effectively be used to predict effective electrophoretic mobilities of neutral analytes from the determined carbon number equivalents or from octanol-water partition coefficients provided that the solvation parameters of the analytes of interest are similar to those of the reference analytes.

  14. [Methods quantitative for determination of water-soluble vitamins in premixes and fortified food products by micellar electrokinetic chromatography on short end of the capillary].

    Science.gov (United States)

    Bogachuk, M N; Bessonov, V V; Perederiaev, O I

    2011-01-01

    It was purposed new technique by micellar electrokinetic chromatography on short end of the capillary (capillary electrophoresis system Agilent 3D CE, DAD, quartz capillary HPCE stndrd cap 56 cm, 50 microm, 50 mM borate buffer pH=9,3, 100 mM sodium dodecil sulfate) for simultaneous determination of water-soluble vitamins (B1, B2, B6, B12, PP, B5, B9, C, B8) in fortified food products and premixes. It was observed on 6 samples of vitamin premixes and 28 samples of fortified food products using this technique. Our findings are consistent with the results of research on certain vitamins, conducted by other methods. The developed technique can be used in analysis of water-soluble vitamins in premixes and fortified food products.

  15. Neutron- and light-scattering studies of the liquid-to-glass and glass-to-glass transitions in dense copolymer micellar solutions

    International Nuclear Information System (INIS)

    Chen Weiren; Chen Sowhsin; Mallamace, Francesco; Glinka, Charles J.; Fratini, Emiliano

    2003-01-01

    Recent mode coupling theory (MCT) calculations show that if a short-range attractive interaction is added to the pure hard sphere system, one may observe a new type of glass originating from the clustering effect (the attractive glass) as a result of the attractive interaction. This is in addition to the known glass-forming mechanism due to the cage effect in the hard sphere system (the repulsive glass). The calculations also indicate that if the range of attraction is sufficiently short compared to the diameter of the particle, within a certain interval of volume fractions where the two glass-forming mechanisms nearly balance each other, varying the external control parameter, the effective temperature, makes the glass-to-liquid-to-glass reentrance and the glass-to-glass transitions possible. Here we present experimental evidence of both transitions, obtained from small-angle neutron-scattering and photon correlation measurements taken from dense L64 copolymer micellar solutions in heavy water. Varying the temperature in certain predicted volume fraction range triggers a sharp transition between these two different types of glass. In particular, according to MCT, there is an end point (called A 3 singularity) of this glass-to-glass transition line, beyond which the long-time dynamics of the two glasses become identical. Our findings confirm this theoretical prediction. Surprisingly, although the Debye-Waller factors, the long-time limit of the coherent intermediate scattering functions, of these two glasses obtained from photon correlation measurements indeed become identical at the predicted volume fraction, they exhibit distinctly different intermediate time relaxation. Furthermore, our experimental results obtained from volume fractions beyond the end point are characterized by the same features as the repulsive glass obtained before the end point. A complete phase diagram giving the boundaries of the structural arrest transitions for L64 micellar system is

  16. Determination of the quaternary structural states of bovine casein by small-angle X-ray scattering: submicellar and micellar forms

    International Nuclear Information System (INIS)

    Kumosinski, T.F.; Pessen, H.; Farrell, H.M. Jr.; Brumberger, H.

    1988-01-01

    Whole casein occurs in milk as a spherical colloidal complex of protein and salts called the casein micelle, with approximate average radii of 650 A as determined by electron microscopy. Removal of Ca2+ is thought to result in dissociation into smaller noncolloidal protein complexes called submicelles. Hydrodynamic and light scattering studies on whole casein submicelles suggest that they are predominantly spherical particles with a hydrophobic core. To investigate whether the integrity of a hydrophobically stabilized submicellar structure is preserved in the electrostatically stabilized colloidal micellar structure, small-angle X-ray scattering (SAXS) experiments were undertaken on whole casein from bovine milk under submicellar and micellar conditions. All SAXS results showed multiple Gaussian character and could be analyzed best by nonlinear regression in place of the customary Guinier plot. Analysis of the SAXS data for submicellar casein showed two Gaussian components which could be interpreted in terms of a particle with two concentric regions of different electron density, designated as a compact core and a loose shell, respectively. The submicelle was found to have an average molecular weight of 285,000 +/- 14,600 and a mass fraction of higher electron density core, k, of 0.212 +/- 0.028. The radius of gyration of the core, RC, was 37.98 +/- 0.01 A with an electron density difference, delta rho C, of 0.0148 +/- 0.0014 e-/A3, while the loose region had values of RL = 88.2 +/- 0.8 A with delta rho L = 0.0091 +/- 0.0003 e-/A3. Calculated distance distribution functions and normalized scattering curves also were consistent with an overall spherical particle with a concentric spherical inner core of higher electron density. (Abstract Truncated)

  17. Stable curcumin-loaded polymeric micellar formulation for enhancing cellular uptake and cytotoxicity to FLT3 overexpressing EoL-1 leukemic cells.

    Science.gov (United States)

    Tima, Singkome; Anuchapreeda, Songyot; Ampasavate, Chadarat; Berkland, Cory; Okonogi, Siriporn

    2017-05-01

    The present study aims to develop a stable polymeric micellar formulation of curcumin (CM) with improved solubility and stability, and that is suitable for clinical applications in leukemia patients. CM-loaded polymeric micelles (CM-micelles) were prepared using poloxamers. The chemical structure of the polymers influenced micellar properties. The best formulation of CM-micelles, namely CM-P407, was obtained from poloxamer 407 at drug to polymer ratio of 1:30 and rehydrated with phosphate buffer solution pH 7.4. CM-P407 exhibited the smallest size of 30.3±1.3nm and highest entrapment efficiency of 88.4±4.1%. When stored at -80°C for 60days, CM-P407 retained high protection of CM and had no significant size change. In comparison with CM solution in dimethyl sulfoxide (CM-DMSO), CM kinetic degradation in both formulations followed a pseudo-first-order reaction, but the half-life of CM in CM-P407 was approx. 200 times longer than in CM-DMSO. Regarding the activity against FLT3 overexpressing EoL-1 leukemic cells, CM-P407 showed higher cytotoxicity than CM-DMSO. Moreover, intracellular uptake to leukemic cells of CM-P407 was 2-3 times greater than that of CM-DMSO. These promising results for CM-P407 will be further investigated in rodents and in clinical studies for leukemia treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Multimedia content classification metrics for content adaptation

    OpenAIRE

    Fernandes, Rui; Andrade, M.T.

    2015-01-01

    Multimedia content consumption is very popular nowadays. However, not every content can be consumed in its original format: the combination of content, transport and access networks, consumption device and usage environment characteristics may all pose restrictions to that purpose. One way to provide the best possible quality to the user is to adapt the content according to these restrictions as well as user preferences. This adaptation stage can be best executed if knowledge about the conten...

  19. Multimedia content classification metrics for content adaptation

    OpenAIRE

    Fernandes, Rui; Andrade, M.T.

    2016-01-01

    Multimedia content consumption is very popular nowadays. However, not every content can be consumed in its original format: the combination of content, transport and access networks, consumption device and usage environment characteristics may all pose restrictions to that purpose. One way to provide the best possible quality to the user is to adapt the content according to these restrictions as well as user preferences. This adaptation stage can be best executed if knowledge about the conten...

  20. Copolimerização micelar de poli(acrilamida-g-óxido de propileno: avaliação reológica e caracterização de suas soluções Micellar copolymerization of poly(acrylamide-g-propylene oxide: rheologic evaluation and solution characterization

    Directory of Open Access Journals (Sweden)

    Bianca L. Sadicoff

    2001-06-01

    Full Text Available Copolímeros graftizados de poliacrilamida e poli(óxido de propileno (PPO foram sintetizados via técnica de polimerização micelar. Foram investigadas as mudanças de viscosidade das suas soluções frente à variação do teor de monômero hidrófobo incorporado ao copolímero, adição de sal e de tensoativo. O maior teor de grupos hidrófobos resultou em aumento da viscosidade aparente das soluções poliméricas. A adição de sal provocou maior interação entre os grupos hidrófobos verificada pela desestabilização do sistema polimérico. A adição de tensoativos gerou decréscimo das viscosidades reduzidas das soluções poliméricas. Os copolímeros obtidos foram caracterizados, qualitativamente, por espectrometria de absorção na região do infravermelho (FTIR.Graft copolymers of polyacrylamide and poly(propylene oxide (PPO were synthesized by a micellar copolymerization technique. The rheological properties of the copolymers solutions were evaluated and compared with literature data for solutions of the same copolymers, synthesized by solution polymerization. The effect of hydrophobe content, salt addition and surfactant addition on the rheological properties were also investigated. Increasing hydrophobe content resulted in higher solution viscosities in the semi-dilute regime. Upon addition of salts, the hydrophobic groups associated to minimize their exposure to water. In the semi-dilute region, higher contents of surfactant added resulted in lower reduced viscosities of the polymer solutions. The copolymers were qualitatively characterized by infra-red spectrometry (IR.

  1. Micellar induced regioselectivity in the two-step consecutive reaction of SO3(2-) with Br-(CH2CH2)n-Br (n=2-5).

    Science.gov (United States)

    Currie, Fredrik; Jarvoll, Patrik; Holmberg, Krister; Romsted, Laurence S; Gunaseelan, Krishnan

    2007-08-15

    High field (800 MHz) (1)H NMR was used to monitor the two-step consecutive reaction of excess SO(3)(2-) with symmetrical bifunctional alpha,omega-dibromoalkanes with butane (DBB), hexane (DBH), octane (DBO), and decane (DBD) chains in CTAB micelles at 25 degrees C. The first-order rate constant for the first substitution step for DBB and DBH is about 5 times faster than for the second, but the kinetics for DBO and DBD were not cleanly first-order. After 40 min, the solution contained about 80% of the intermediate bromoalkanesulfonate from DBB and DBH and the remainder is alkanedisulfonate and unreacted starting material. The same reactions were carried out in homogeneous MeOH/D(2)O solutions at 50 degrees C. The rate constants for all four alpha,omega-dibromoalkanes were first-order throughout the time course of the reaction and the same within +/-10%. However, because micellar solutions are organized on the nanoscale and bring together lipophilic and hydrophilic reactants into a small reaction volume at the micellar interface, they speed this substitution reaction considerably compared to reaction in MeOH/D(2)O. The CTAB micelles also induce a significant regioselectivity in product formation by speeding the first step of the consecutive reaction more than the second. The results are consistent with the bromoalkanesulfonate intermediates having a radial orientation within the micelles with the -CH(2)SO(3)(-) group in the interfacial region and the -CH(2)Br group directed into the micellar core such that the concentration of -CH(2)Br groups in the reactive zone, i.e., the micellar interface, is significantly reduced. These results provide the first example of self-assembled surfactant system altering the relative rates of the reaction steps of a consecutive reaction and, in doing so, enhancing monosubstitution of a symmetrically disubstituted species.

  2. pH multistage responsive micellar system with charge-switch and PEG layer detachment for co-delivery of paclitaxel and curcumin to synergistically eliminate breast cancer stem cells.

    Science.gov (United States)

    Yang, Zhe; Sun, Na; Cheng, Rui; Zhao, Chenyang; Liu, Zerong; Li, Xian; Liu, Jie; Tian, Zhongmin

    2017-12-01

    Several studies have demonstrated that cancer stem cells (CSCs) are responsible for replenishing bulk tumor cells, generating new tumors and causing metastasis and relapse. Although combination therapy with multiple chemotherapeutics is considered to be a promising approach for simultaneously eliminating non-CSCs and CSCs, it is difficult to deliver drugs into the inner region of a solid tumor where the CSCs are located due to a lack of capillaries. Here, we synthesized a pH-sensitive polymer, poly(ethylene glycol)-benzoic imine-poly(γ-benzyl-l-aspartate)-b-poly(1-vinylimidazole) block copolymer (PPBV), to develop a pH multistage responsive micellar system for co-delivering paclitaxel and curcumin and synergistically eliminating breast cancer stem cells (bCSCs) and non-bCSCs. This pH multistage responsive micellar system could intelligently switch its surface charge from neutral to positive, de-shield its PEG layer and reduce its size after long-circulation and extravasation from leaky blood vessels at tumor sites, thus facilitating their cellular uptake and deep tumor penetration. These advantages were also beneficial for the combinational therapy efficacy of PTX and CUR to reach the maximum level and achieve superior tumor inhibition activity and effective bCSCs-killing capacity in vivo. Consequently, this pH multistage responsive micellar system is a powerful platform for collaborative therapy with PTX and CUR to simultaneously eliminate bCSCs and non-CSCs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Micellar casein concentrate production with a 3X, 3-stage, uniform transmembrane pressure ceramic membrane process at 50°C.

    Science.gov (United States)

    Hurt, E; Zulewska, J; Newbold, M; Barbano, D M

    2010-12-01

    The production of serum protein (SP) and micellar casein from skim milk can be accomplished using microfiltration (MF). Potential commercial applications exist for both SP and micellar casein. Our research objective was to determine the total SP removal and SP removal for each stage, and the composition of retentates and permeates, for a 3×, continuous bleed-and-feed, 3-stage, uniform transmembrane pressure (UTP) system with 0.1-μm ceramic membranes, when processing pasteurized skim milk at 50°C with 2 stages of water diafiltration. For each of 4 replicates, about 1,100 kg of skim milk was pasteurized (72°C, 16s) and processed at 3× through the UTP MF system. Retentate from stage 1 was cooled to <4°C and stored until the next processing day, when it was diluted with reverse osmosis water back to a 1× concentration and again processed through the MF system (stage 2) to a 3× concentration. The retentate from stage 2 was stored at <4°C, and, on the next processing day, was diluted with reverse osmosis water back to a 1× concentration, before running through the MF system at 3× for a total of 3 stages. The retentate and permeate from each stage were analyzed for total nitrogen, noncasein nitrogen, and nonprotein nitrogen using Kjeldahl methods; sodium dodecyl sulfate-PAGE analysis was also performed on the retentates from each stage. Theoretically, a 3-stage, 3× MF process could remove 97% of the SP from skim milk, with a cumulative SP removal of 68 and 90% after the first and second stages, respectively. The cumulative SP removal using a 3-stage, 3× MF process with a UTP system with 0.01-μm ceramic membranes in this experiment was 64.8 ± 0.8, 87.8 ± 1.6, and 98.3 ± 2.3% for the first, second, and third stages, respectively, when calculated using the mass of SP removed in the permeate of each stage. Various methods of calculation of SP removal were evaluated. Given the analytical limitations in the various methods for measuring SP removal, calculation

  4. On the mechanism of dechlorination of polychlorinated biphenyls (PCBs) induced by electron beam irradiation in aqueous and aqueous micellar solutions, transformer oil, and sediment

    International Nuclear Information System (INIS)

    Chaychian, M.; Silverman, J.; Al-Sheirkhly, M.

    2011-01-01

    Complete text of publication follows. The widespread release of PCBs into the environment presents a serious problem due to their persistence and toxicity. Ionizing radiation, such as gamma rays and high-energy electron beam, is remarkably effective in dechlorinating PCBs into biphenyls. The kinetics of the reductive dechlorination of PCBs in aqueous and aqueous micellar solutions and in transformer oil is being studied by pulse radiolysis and steady-state radiolysis. In aqueous micellar solutions, dichlori-, tetrachloro-, and decachlorobiphenyl congeners were solubilized in water using a commercially available non-ionic surfactant, Triton X-100, and subsequently pulse irradiated by electron accelerator using optical detection method. The reaction rate constant between decachlorobiphenyl and aqueous electrons e aq ·- , and Triton with e aq ·- in the 2% Triton solution, were measured as 2.6 x 10 9 Lmol -1 s -1 and 1.2 x 10 7 Lmol -1 s -1 , respectively. We have also measured in aqueous solutions, the reaction rate constant of e aq ·- with dichlorobiphenyl as 3.8 x 10 9 Lmol -1 s -1 . In aqueous-propanol, the reaction rate constants of e aq ·- with dichlorobiphenyl, tetrachlorobiphenyl, and dechachlorobiphenyl are 2 x 10 9 Lmol -1 s -1 , 3 x 10 9 Lmol -1 s -1 , and 7 x 10 9 Lmol -1 s -1 , respectively. In addition to the presence of PCBs as high-dielectric component, transformer oil contains many aromatic hydrocarbons; the most abundant being biphenyl, fluorine, and phenanthrene. Solvated electrons formed by irradiation of the oil react either with PCB to lead to dechlorination or with the aromatic hydrocarbons present in the oil to form radical anions. These species are shown to transfer an electron to chlorinated biphenyls relative rapidly, leading to dechlorination. The rate constants for several such reactions, determined in 2-propanol solutions, are in the range of 10 7 - 10 8 Lmol -1 s -1 . These rapid reactions explain why PCB can be dechlorinated in oil

  5. Transferrin receptor-targeted pH-sensitive micellar system for diminution of drug resistance and targetable delivery in multidrug-resistant breast cancer

    Directory of Open Access Journals (Sweden)

    Gao W

    2017-02-01

    Full Text Available Wei Gao,1 Guihua Ye,1 Xiaochuan Duan,1 Xiaoying Yang,1 Victor C Yang1,2 1Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics (Theranostics, School of Pharmacy, Tianjin Medical University, Tianjin, People’s Republic of China; 2Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, MI, USA Abstract: The emergence of drug resistance is partially associated with overproduction of transferrin receptor (TfR. To overcome multidrug resistance (MDR and achieve tumor target delivery, we designed a novel biodegradable pH-sensitive micellar system modified with HAIYPRH, a TfR ligand (7pep. First, the polymers poly(l-histidine-coupled polyethylene glycol-2000 (PHIS-PEG2000 and 7pep-modified 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-polyethylene glycol-2000 (7pep-DSPE-PEG2000 were synthesized, and the mixed micelles were prepared by blending of PHIS-PEG2000 and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-polyethylene glycol-2000 (DSPE-PEG2000 or 7pep-DSPE-PEG2000 (7-pep HD micelles. The micelles exhibited good size uniformity, high encapsulation efficiency, and a low critical micelle concentration. By changing the polymer ratio in the micellar formulation, the pH response range was specially tailored to pH ~6.0. When loaded with antitumor drug doxorubicin (DOX, the micelle showed an acid pH-triggering drug release profile. The cellular uptake and cytotoxicity study demonstrated that 7-pep HD micelles could significantly enhance the intracellular level and antitumor efficacy of DOX in multidrug-resistant cells (MCF-7/Adr, which attributed to the synergistic effect of poly(l-histidine-triggered endolysosom escape and TfR-mediated endocytosis. Most importantly, the in vivo imaging study confirmed the targetability of 7-pep HD micelles to MDR tumor. These findings indicated that 7-pep HD micelles would be a promising drug delivery system in the treatment of drug

  6. Robust analysis of the hydrophobic basic analytes loratadine and desloratadine in pharmaceutical preparations and biological fluids by sweeping-cyclodextrin-modified micellar electrokinetic chromatography.

    Science.gov (United States)

    El-Awady, Mohamed; Belal, Fathalla; Pyell, Ute

    2013-09-27

    The analysis of hydrophobic basic analytes by micellar electrokinetic chromatography (MEKC) is usually challenging because of the tendency of these analytes to be adsorbed onto the inner capillary wall in addition to the difficulty to separate these compounds as they exhibit extremely high retention factors. A robust and reliable method for the simultaneous determination of loratadine (LOR) and its major metabolite desloratadine (DSL) is developed based on cyclodextrin-modified micellar electrokinetic chromatography (CD-MEKC) with acidic sample matrix and basic background electrolyte (BGE). The influence of the sample matrix on the reachable focusing efficiency is studied. It is shown that the application of a low pH sample solution mitigates problems associated with the low solubility of the hydrophobic basic analytes in aqueous solution while having advantages with regard to on-line focusing. Moreover, the use of a basic BGE reduces the adsorption of these analytes in the separation compartment. The separation of the studied analytes is achieved in less than 7min using a BGE consisting of 10mmolL(-1) disodium tetraborate buffer, pH 9.30 containing 40mmolL(-1) SDS and 20mmolL(-1) hydroxypropyl-β-CD while the sample solution is composed of 10mmolL(-1) phosphoric acid, pH 2.15. A full validation study of the developed method based on the pharmacopeial guidelines is performed. The method is successfully applied to the analysis of the studied drugs in tablets without interference of tablet additives as well as the analysis of spiked human urine without any sample pretreatment. Furthermore, DSL can be detected as an impurity in LOR bulk powder at the stated pharmacopeial limit (0.1%, w/w). The selectivity of the developed method allows the analysis of LOR and DSL in combination with the co-formulated drug pseudoephedrine. It is shown that in CD-MEKC with basic BGE, solute-wall interactions are effectively suppressed allowing the development of efficient and precise

  7. Digital Content Strategies

    OpenAIRE

    Halbheer, Daniel; Stahl, Florian; Koenigsberg, Oded; Lehmann, Donald R

    2013-01-01

    This paper studies content strategies for online publishers of digital information goods. It examines sampling strategies and compares their performance to paid content and free content strategies. A sampling strategy, where some of the content is offered for free and consumers are charged for access to the rest, is known as a "metered model" in the newspaper industry. We analyze optimal decisions concerning the size of the sample and the price of the paid content when sampling serves the dua...

  8. Micellar Enhanced Spectrofluorimetric Method for the Determination of Ponatinib in Human Plasma and Urine via Cremophor RH 40 as Sensing Agent

    Directory of Open Access Journals (Sweden)

    Hany W. Darwish

    2015-01-01

    Full Text Available An impressively simple and precise spectrofluorimetric procedure was established and validated for ponatinib (PTB quantitation in biological fluids such as human plasma and human urine. This method depends on examining the fluorescence characteristics of PTB in a micellar system of Cremophor RH 40 (Cr RH 40. Cr RH 40 enhanced the intrinsic fluorescence of PTB distinctly in aqueous water. The fluorescence spectra of PTB was recorded at 457 nm following its excitation at 305 nm. Maximum fluorescence intensity was attained by addition of 0.7 mL of Cr RH 40 and one mL of phosphate buffer to PTB aliquots and then dilution with distilled water. There is a linear relationship between the fluorescence intensity of PTB and its concentration over the range 5–120 ngmL−1, with limit of detection and limit of quantification equal to 0.905 ngmL−1 and 2.742 ngmL−1, respectively. The accuracy and the precisions of the proposed method were checked and gave adequate results. The adopted method was applied with a great success for PTB quantitation in different biological matrices (spiked human plasma and urine giving high recovery values.

  9. Rapid Determination of Amino Acids in Beer, Red Wine, and Donkey-Hide Gelatin by Gradient Elution of HPLC: From Micellar Liquid Chromatography to High Submicellar Liquid Chromatography.

    Science.gov (United States)

    Xie, Yunfei; Luo, Tian; Yang, Jing; Dong, Yuming

    2018-01-01

    Amino acids (AAs) in beer, red wine, and donkey-hide gelatin were rapidly determined by gradient LC elution from micellar LC to high submicellar LC. Mobile phase A was a 0.075 M sodium dodecyl sulfate solution containing 20 mM ammonium acetate with a pH value adjusted to 3.5 with acetic acid solution, and mobile phase B was acetonitrile. Optimized chromatographic conditions were as follows: mobile phase B increased from 25 to 60% (v/v) in 30 min and the use of a Venusil XBP C18 column (5 µm, 250 × 4.6 mm) as the stationary phase, with a column temperature of 35°C, flow rate of 1.2 mL/min, and detection wavelength of 266 nm. The results indicated good linearity (r2 ≥ 0.9924). The intraday precision of the retention time was RSD ≤ 1.1%, whereas interday was RSD ≤ 3.2%; intraday precision of the peak area was RSD ≤ 3.3%, whereas interday was RSD ≤ 4.9%. The range of recovery was 94.6-102.4%. The RSDs of the retention time for the AAs for the different samples were 0.04-0.31%.

  10. [Simultaneous determination of five alkaloids in Niuhuang Shangqing Tablets by micellar electrokinetic chromatography-mass spectrometry using laurel acyl malic acid ester].

    Science.gov (United States)

    Hu, Mengdi; Su, Di; Fan, Xiaosu; Yu, Jianhua; Xu, Yuanjin

    2012-12-01

    A micellar electrokinetic chromatography-mass spectrometric method based on laurel acyl malic acid ester (LMAE) for the separation and determination of coptisine, berberine, jatrorrhizine, phellodendrine and ligustrazine in Niuhuang Shangqing Tablets was established. The baseline separation of the five compounds was attained within 18 min by an uncoated capillary (88 cm x 50 microm) on the operating voltage of 25 kV using 7.5 mmol/L LMAE-15 mmol/L ammonia-50 mmol/L ammonium acetate mixture (pH = 7.0) containing 12.5% (v/v) acetonitrile as the electrophoretic medium and 50% 2-propanol aqueous solution (containing 3 mmol/L acetic acid) as the sheath liquid. The peak area of each component to its concentration showed a good linear relationship. The relative standard deviations of migration times and peak areas of the five components were less than 5% and the recoveries were between 96.0% and 105%. The developed method is simple, rapid, accurate and is suitable for the routine analysis of the five alkaloid components in Niuhuang Shangqing Tablets.

  11. Dual cloud point extraction coupled with hydrodynamic-electrokinetic two-step injection followed by micellar electrokinetic chromatography for simultaneous determination of trace phenolic estrogens in water samples.

    Science.gov (United States)

    Wen, Yingying; Li, Jinhua; Liu, Junshen; Lu, Wenhui; Ma, Jiping; Chen, Lingxin

    2013-07-01

    A dual cloud point extraction (dCPE) off-line enrichment procedure coupled with a hydrodynamic-electrokinetic two-step injection online enrichment technique was successfully developed for simultaneous preconcentration of trace phenolic estrogens (hexestrol, dienestrol, and diethylstilbestrol) in water samples followed by micellar electrokinetic chromatography (MEKC) analysis. Several parameters affecting the extraction and online injection conditions were optimized. Under optimal dCPE-two-step injection-MEKC conditions, detection limits of 7.9-8.9 ng/mL and good linearity in the range from 0.05 to 5 μg/mL with correlation coefficients R(2) ≥ 0.9990 were achieved. Satisfactory recoveries ranging from 83 to 108% were obtained with lake and tap water spiked at 0.1 and 0.5 μg/mL, respectively, with relative standard deviations (n = 6) of 1.3-3.1%. This method was demonstrated to be convenient, rapid, cost-effective, and environmentally benign, and could be used as an alternative to existing methods for analyzing trace residues of phenolic estrogens in water samples.

  12. Micellar Enhanced Three-Dimensional Excitation-Emission Matrix Fluorescence for Rapid Determination of Antihypertensives in Human Plasma with Aid of Second-Order Calibration Methods

    Directory of Open Access Journals (Sweden)

    Hai-Yan Fu

    2015-01-01

    Full Text Available A highly sensitive three-dimensional excitation-emission fluorescence method was proposed to determine antihypertensives including valsartan and amlodipine besylate in human plasma with the aid of second-order calibration methods based on parallel factor analysis (PARAFAC and alternating trilinear decomposition (ATLD algorithms. Antihypertensives with weak fluorescent can be transformed into a strong fluorescent property by changing microenvironment in samples using micellar enhanced surfactant. Both the adopted algorithms with second-order advantage can improve the resolution and directly attain antihypertensives concentration even in the presence of potential strong intrinsic fluorescence from human plasma. The satisfactory results can be achieved for valsartan and amlodipine besylate in complicated human plasma. Furthermore, some statistical parameters and figures of merit were evaluated to investigate the performance of the proposed method, and the accuracy and precision of the proposed method were also validated by the elliptical joint confidence region (EJCR test and repeatability analysis of intraday and interday assay. The proposed method could not only light a new avenue to directly determine valsartan or amlodipine besylate in human plasma, but also hold great potential to be extended as a promising alternative for more practical applications in the determination of weak fluorescent drugs.

  13. Characterization and optimization of carboxylesterase-catalyzed esterification between capric acid and glycerol for the production of 1-monocaprin in reversed micellar system.

    Science.gov (United States)

    Park, Kyung Min; Kwon, Oh Taek; Ahn, Seon Min; Lee, JaeHwan; Chang, Pahn-Shick

    2010-02-28

    Calotropis procera R. Br. carboxylesterase (EC 3.1.1.1) solubilized in reversed micellar glycerol droplets containing a very small amount of water (less than 5ppm) and stabilized by a surfactant effectively catalyzed the esterification between glycerol and capric acid to produce 1-monocaprin. Reaction variables including surfactant types, organic solvent media, reaction time, G-value ([glycerol]/[capric acid]), R-value ([water]/[surfactant]), pH, temperature, and types of metal ion inhibitors on the carboxylesterase-catalyzed esterification were characterized and optimized to efficiently produce 1-monocaprin. Bis(2-ethylhexyl) sodium sulfosuccinate (AOT) and isooctane were the most effective surfactant and organic solvent medium, respectively, for 1-monocaprin formation in reversed micelles. The optimum G- and R-values were 3.0 and 0.05, respectively, and the optimum pH and temperature were determined to be 10.0 and 60 degrees C, respectively. K(m,app.) and V(max,app.) were calculated from a Hanes-Woolf plot, and the values were 9.64 mM and 2.45 microM/min mg protein, respectively. Among various metal ions, Cu(2+) and Fe(2+) severely inhibited carboxylesterase-catalyzed esterification activity (less than 6.0% of relative activity). Copyright 2009 Elsevier B.V. All rights reserved.

  14. Monitoring the quality consistency of Fufang Danshen Pills using micellar electrokinetic chromatography fingerprint coupled with prediction of antioxidant activity and chemometrics.

    Science.gov (United States)

    Ji, Zhengchao; Sun, Wanyang; Sun, Guoxiang; Zhang, Jin

    2016-08-01

    A fast micellar electrokinetic chromatography fingerprint method combined with quantification was developed and validated to evaluate the quality of Fufang Danshen Pills, a traditional Chinese Medicine, which has been used in the treatment of cardiovascular system diseases, in which the tetrahedron optimization method was first used to optimize the background electrolyte solution. Subsequently, the index of the fingerprint information amount of I was performed as an excellent objective indictor to investigate the experimental conditions. In addition, a systematical quantified fingerprint method was constructed for evaluating the quality consistency of 20 batches of test samples obtained from the same drug manufacturer. The fingerprint analysis combined with quantitative determination of two components showed that the quality consistency of the test samples was quite good within the same commercial brand. Furthermore, the partial least squares model analysis was used to explore the fingerprint-efficacy relationship between active components and antioxidant activity in vitro, which can be applied for the assessment of anti-oxidant activity of Fufang Danshen pills and provide valuable medicinal information for quality control. The result illustrated that the present study provided a reliable and reasonable method for monitoring the quality consistency of Fufang Danshen pills. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Sensitive Detection of Organophosphorus Pesticides in Medicinal Plants Using Ultrasound-Assisted Dispersive Liquid-Liquid Microextraction Combined with Sweeping Micellar Electrokinetic Chromatography.

    Science.gov (United States)

    Wei, Jin-Chao; Hu, Ji; Cao, Ji-Liang; Wan, Jian-Bo; He, Cheng-Wei; Hu, Yuan-Jia; Hu, Hao; Li, Peng

    2016-02-03

    A simple, rapid, and sensitive method using ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME) combined with sweeping micellar electrokinetic chromatography (sweeping-MEKC) has been developed for the determination of nine organophosphorus pesticides (chlorfenvinphos, parathion, quinalphos, fenitrothion, azinphos-ethyl, parathion-methyl, fensulfothion, methidathion, and paraoxon). The important parameters that affect the UA-DLLME and sweeping efficiency were investigated. Under the optimized conditions, the proposed method provided 779.0-6203.5-fold enrichment of the nine pesticides compared to the normal MEKC method. The limits of detection ranged from 0.002 to 0.008 mg kg(-1). The relative standard deviations of the peak area ranged from 1.2 to 6.5%, indicating the good repeatability of the method. Finally, the developed UA-DLLME-sweeping-MEKC method has been successfully applied to the analysis of the investigated pesticides in several medicinal plants, including Lycium chinense, Dioscorea opposite, Codonopsis pilosula, and Panax ginseng, indicating that this method is suitable for the determination of trace pesticide residues in real samples with complex matrices.

  16. Sustained-release diclofenac potassium-loaded solid lipid microparticle based on solidified reverse micellar solution: in vitro and in vivo evaluation.

    Science.gov (United States)

    Chime, Salome Amarachi; Attama, Anthony Amaechi; Builders, Philip F; Onunkwo, Godswill C

    2013-01-01

    To formulate sustained-release diclofenac potassium-loaded solid lipid microparticles (SLMs) based on solidified reverse micellar solution (SRMS) and to evaluate the in vitro and in vivo properties. SRMS consisting of mixtures of Phospholipon® 90H and Softisan® 154 were used to formulate diclofenac potassium-loaded SLMs. Characterization based on the particle size and morphology, stability and encapsulation efficiency (EE%) were carried out on the SLMs. In vitro release was carried out in simulated intestinal fluid (pH 7.5). Anti-inflammatory and ulcerogenic properties were studied using rats. Maximum EE% of 95%, 94% and 93% were obtained for SLMs formulated with SRMS 1:1, 2:1 and 1:2, respectively. In vitro release showed about 85-90% drug release at 13 h. Diclofenac potassium-loaded SLMs showed good anti-inflammatory and gastro-protective properties. Diclofenac potassium-loaded SLMs based on SRMS could be used orally or parenterally under controlled conditions, for once daily administration.

  17. Fluorescence ratiometric sensing of polyols by phenylboronic acid complexes with ligands exhibiting excited-state intramolecular proton transfer in aqueous micellar media

    Energy Technology Data Exchange (ETDEWEB)

    Trejo-Huizar, Karla Elisa; Jiménez-Sánchez, Arturo; Martínez-Aguirre, Mayte A.; Yatsimirsky, Anatoly K., E-mail: anatoli@unam.mx

    2016-11-15

    2-Phenyl-3-hydroxy-4(1H)-quinolone possessing dual fluorescence due to excited-state intramolecular proton transfer (ESIPT) forms stable complex with phenylboronic acid with blue shifted emission maximum in micellar medium of a cationic surfactant even though the compound lacks required for complexation with boronic acids cis-diol structure. No complexation is observed in the presence of neutral or anionic surfactants. Titrations of this complex with polyols including sugars and nucleotides at pH 8 displace free quinolone showing ratiometric response, which allows determination of polyols with detection limits 0.05–1 mM and unusually wide linear dynamic ranges. Another ESIPT dye 2-(2′-hydroxyphenyl)−1H-benzimidazole also lacking cis-diol structure forms equally stable complex with phenylboronic acid and allows ratiometric determination of polyols with similar characteristics. The results of this study demonstrate that blocking ESIPT of signaling molecule by complexation of the receptor with the proton donor group eliminates the low energy emission from tautomeric form but strongly enhances the high energy emission typical for “normal” form of signaling molecule creating a possibility of ratiometric sensing.

  18. Development and Validation of a Micellar Capillary Electrophoresis Method for Determination of IFNβ-1b in Lyophilized Formulation of a Biosimilar Product.

    Science.gov (United States)

    Dadgarnejad, Manuchehr; Rastegar, Hosein; Ilka, Hooshmand; Shekarchi, Maryam; Adib, Nooshin; Alebouyeh, Mahmood; Keypour, Nadia; Shoeibi, Shahram; Kobarfard, Farzad; Fazeli, Mohammad Reza

    2015-01-01

    Human interferons (IFNs) are key cytokines secreted by immune system. They have several effects such as antiviral and anti tumors activity, activating immune cells and healing of multiple sclerosis. The type IFNs present in humans are α ,β and Υ. IFN β is a polypeptide, normally produced by fibroblasts and seems to be more species-specific than IFN. Structural properties of IFNs are important for their biologic effects. There are a few analytical techniques for separation, identification and determination of IFNs in its formulations such as mass spectroscopy, RP-HPLC and capillary electrophoresis (CE). In this study we used Micellar Electrokinetic Chromatography (MEKC) as a unique mode of CE because of its capability to separate neutral as well as charged solutes. We used sodium tetraborate (Borax) as buffer without any modifier and sodium dodecyl sulfate (SDS) as surfactant. The optimum MECK running buffer consisted of Borate 50 Mm; SDS 20 mM pH =9.6. The validated method was used for determination of the IFN β-1b formulation which is manufactured in Iran. From 9 collected different batches, all of them had acceptable potency as claimed on their label with average 102.25 ±10.030 %. This is the first time that a MEKC method is introduced for quantification of IFN β-1b in its pharmaceutical dosage forms. The method is reliable safe, rapid and accurate.

  19. Simultaneous determination of tyramine and tryptamine and their precursor amino acids by micellar liquid chromatography and pulsed amperometric detection in wines.

    Science.gov (United States)

    Gil-Agustí, M; Carda-Broch, S; Monferrer-Pons, Ll; Esteve-Romero, J

    2007-07-13

    Two biogenic amines, tryptamine and tyramine, and their precursors, tryptophan and tyrosine, were determined by a liquid chromatographic procedure. A hybrid micellar mobile phase of sodium dodecyl sulphate (SDS) and 1-propanol, a C18 column and electrochemical detection were used. A pH study in the range of 3-9 was performed and pH 3 was finally selected in accordance with resolution and analysis time. Oxidation potential was also checked in the range 0.6-0.9V: the maximum area obtained in all those potentials was at 0.8V, which was selected to carry out the analysis using a sequence of pulsed amperometric detection waveform. The four compounds were resolved using a mobile phase of 0.15M SDS-5% 1-propanol with an analysis time of 16 min. Repeatabilities and intermediate precision were evaluated at three different concentrations for each compound with RSD values lower than 2.6 and 4.8%, respectively. Limits of detection and quantification were also obtained within the 10-40 and 33-135 ng/ml ranges, respectively. Finally, the applicability of the procedure was tested in several types of wine and no matrix effect was observed. The possibility of direct sample introduction simplifies and greatly expedites the treatments with reduced cost, improving the accuracy of the procedures.

  20. Shuffling cross-validation-bee algorithm as a new descriptor selection method for retention studies of pesticides in biopartitioning micellar chromatography.

    Science.gov (United States)

    Zarei, Kobra; Atabati, Morteza; Ahmadi, Monire

    2017-05-04

    Bee algorithm (BA) is an optimization algorithm inspired by the natural foraging behaviour of honey bees to find the optimal solution which can be proposed to feature selection. In this paper, shuffling cross-validation-BA (CV-BA) was applied to select the best descriptors that could describe the retention factor (log k) in the biopartitioning micellar chromatography (BMC) of 79 heterogeneous pesticides. Six descriptors were obtained using BA and then the selected descriptors were applied for model development using multiple linear regression (MLR). The descriptor selection was also performed using stepwise, genetic algorithm and simulated annealing methods and MLR was applied to model development and then the results were compared with those obtained from shuffling CV-BA. The results showed that shuffling CV-BA can be applied as a powerful descriptor selection method. Support vector machine (SVM) was also applied for model development using six selected descriptors by BA. The obtained statistical results using SVM were better than those obtained using MLR, as the root mean square error (RMSE) and correlation coefficient (R) for whole data set (training and test), using shuffling CV-BA-MLR, were obtained as 0.1863 and 0.9426, respectively, while these amounts for the shuffling CV-BA-SVM method were obtained as 0.0704 and 0.9922, respectively.

  1. Benzyl alcohol and block copolymer micellar lithography: a versatile route to assembling gold and in situ generated titania nanoparticles into uniform binary nanoarrays.

    Science.gov (United States)

    Polleux, Julien; Rasp, Matthias; Louban, Ilia; Plath, Nicole; Feldhoff, Armin; Spatz, Joachim P

    2011-08-23

    Simultaneous synthesis and assembly of nanoparticles that exhibit unique physicochemical properties are critically important for designing new functional devices at the macroscopic scale. In the present study, we report a simple version of block copolymer micellar lithography (BCML) to synthesize gold and titanium dioxide (TiO(2)) nanoarrays by using benzyl alcohol (BnOH) as a solvent. In contrast to toluene, BnOH can lead to the formation of various gold nanopatterns via salt-induced micellization of polystyrene-block-poly(vinylpyridine) (PS-b-P2VP). In the case of titania, the use of BCML with a nonaqueous sol-gel method, the "benzyl alcohol route", enables the fabrication of nanopatterns made of quasi-hexagonally organized particles or parallel wires upon aging a (BnOH-TiCl(4)-PS(846)-b-P2VP(171))-containing solution for four weeks to grow TiO(2) building blocks in situ. This approach was found to depend mainly on the relative lengths of the polymer blocks, which allows nanoparticle-induced micellization and self-assembly during solvent evaporation. Moreover, this versatile route enables the design of uniform and quasi-ordered gold-TiO(2) binary nanoarrays with a precise particle density due to the absence of graphoepitaxy during the deposition of TiO(2) onto gold nanopatterns. © 2011 American Chemical Society

  2. Study of flow profile distortions and efficiency in counter pressure moderated partial filling micellar electrokinetic chromatography in relation to the relative buffer zone lengths.

    Science.gov (United States)

    Michalke, Daniela; Welsch, Thomas

    2002-06-25

    The influence of the relative buffer zone lengths on the efficiency was investigated in partial filling micellar electrokinetic chromatography using sodium dodecyl sulfate as separation additive. Varying relative zone lengths were obtained by applying identical initial separation zone lengths but different total lengths of the capillaries. Plate numbers of a homologous series of omega-phenylalcohols were measured to indicate the effect of both a changing relative zone length during the run and a counter pressure applied on the cathodic buffer reservoir. The magnitude and the course of these plate numbers are discussed on the basis of models for flow profile superposition and flow profile deformation which are caused by an intersegmental pressure arising at the boundary between the two buffer zones with different electroosmotic flow velocities. Calculation of the intersegmental pressure and of the resulting laminar flow components in the buffer zones on the basis of some equations for electroosmotic and hydrodynamic flow supported the interpretation that a long background buffer zone should be avoided

  3. Determination of strobilurin fungicide residues in fruits and vegetables by nonaqueous micellar electrokinetic capillary chromatography with indirect laser-induced fluorescence.

    Science.gov (United States)

    Guo, Xin; Wang, Kun; Chen, Guan-Hua; Shi, Jie; Wu, Xian; Di, Lu-Lu; Wang, Yi

    2017-08-01

    A nonaqueous micellar electrokinetic capillary chromatography method with indirect LIF was developed for the determination of strobilurin fungicide residues in fruits and vegetables. Hydrophobic CdTe quantum dots (QDs) synthesized in aqueous phase were used as background fluorescent substance. The BGE solution, QD concentration, and separation voltage were optimized to obtain the best separation efficiency and the highest signal intensity. The optimal BGE solution consists of 40 mM phosphate, 120 mM sodium dodecyl sulfate, 15% v/v water and 15% v/v hydrophobic CdTe QDs in formamide, of which apparent pH is 9.5. The optimized separation voltage is controlled as 25 kV. The resultant detection limits of azoxystrobin, kresoxim-methyl, and pyraclostrobin are all 0.001 mg/kg, their linear dynamic ranges are 0.005-2.5 mg/kg, and the recoveries of the spiked samples are 81.7-96.1%, 86.5-95.7%, and 87.3-97.4%, respectively. This method has been proved to be sensitive enough to detect the aforementioned fungicides in fruits and vegetables at the maximum residue limits. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Publishing and Revising Content

    Science.gov (United States)

    Editors and Webmasters can publish content without going through a workflow. Publishing times and dates can be set, and multiple pages can be published in bulk. Making an edit to published content created a revision.

  5. Plasmaspheric electron content

    International Nuclear Information System (INIS)

    Hartmann, G.K.

    1978-01-01

    Measurements of the plasmaspheric electron content are reviewed with particular reference to the ATS-6 radio beacon experiment. From the review, it appears likely that measurement of the plasmaspheric electron content is the only one capable of monitoring electron fluxes continuously between L 1 and L 2. Some recent important results deduced from plasmaspheric electron content measurements are discussed

  6. Comparison of micellar extraction combined with ionic liquid based vortex-assisted liquid-liquid microextraction and modified quick, easy, cheap, effective, rugged, and safe method for the determination of difenoconazole in cowpea.

    Science.gov (United States)

    Chen, Xiaochu; Bian, Yanli; Liu, Fengmao; Teng, Peipei; Sun, Pan

    2017-10-06

    Two simple sample pretreatment for the determination of difenoconazole in cowpea was developed including micellar extraction combined with ionic liquid based vortex-assisted liquid-liquid microextraction (ME-IL-VALLME) prior to high performance liquid chromatography (HPLC), and modified quick, easy, cheap, effective, rugged, and safe method (QuEChERS) coupled with HPLC-MS/MS. In ME-IL-VALLME method, the target analyte was extracted by surfactant Tween 20 micellar solution, then the supernatant was diluted with 3mL water to decrease the solubility of micellar solution. Subsequently, the vortex-assisted liquid-liquid microextraction (VALLME) procedure was performed in the diluted extraction solution by using the ionic liquid of 1-hexyl-3-methylimidazolium hexafluorophosphate ([HMIM]PF 6 ) as the extraction solvent and Tween 20 as an emulsifier to enhance the dispersion of the water-immiscible ionic liquid into the aqueous phase. Parameters that affect the extraction have been investigated in both methods Under the optimum conditions, the limits of quantitation were 0.10 and 0.05mgkg -1 , respectively. And good linearity was achieved with the correlation coefficient higher than 0.9941. The relative recoveries ranged from 78.6 to 94.8% and 92.0 to 118.0% with the relative standard deviations (RSD) of 7.9-9.6% and 1.2-3.2%, respectively. Both methods were quick, simple and inexpensive. However, the ME-IL-VALLME method provides higher enrichment factor compared with conventional QuEChERS method. The ME-IL-VALLME method has a strong potential for the determination of difenoconazole in complex vegetable matrices with HPLC. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. A new application of micellar liquid chromatography in the determination of free ampicillin concentration in the drug-human serum albumin standard solution in comparison with the adsorption method.

    Science.gov (United States)

    Stępnik, Katarzyna E; Malinowska, Irena; Maciejewska, Małgorzata

    2016-06-01

    The determination of free drug concentration is a very important issue in the field of pharmacology because only the unbound drug fraction can achieve a pharmacological effect. Due to the ability to solubilize many different compounds in micellar aggregates, micellar liquid chromatography (MLC) can be used for direct determination of free drug concentration. Proteins are not retained on the stationary phase probably due to the formation of protein - surfactant complexes which are excluded from the pores of stationary phase. The micellar method is simple and fast. It does not require any pre-preparation of the tested samples for analysis. The main aim of this paper is to demonstrate a completely new applicability of the analytical use of MLC concerning the determination of free drug concentration in the standard solution of human serum albumin. The well-known adsorption method using RP-HPLC and the spectrophotometric technique was applied as the reference method. The results show that the free drug concentration value obtained in the MLC system (based on the RP-8 stationary phase and CTAB) is similar to that obtained by the adsorption method: both RP-HPLC (95.83μgmL(-1), 79.86% of free form) and spectrophotometry (95.71μgmL(-1), 79.76%). In the MLC the free drug concentration was 93.98μgmL(-1) (78.3%). This indicates that the obtained results are within the analytical range of % of free ampicillin fraction and the MLC with direct sample injection can be treated like a promising method for the determination of free drug concentration. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Derivative Quotient Spectrophotometry and an Eco-Friendly Micellar Chromatographic Approach with Time-Programmed UV-Detection for the Separation of Two Fluoroquinolones and Phenazopyridine

    Science.gov (United States)

    Tolba, Manar M.; Salim, Mohamed M.

    2016-01-01

    In this study, two analytical approaches were exploited for the resolution of binary mixtures of ciprofloxacin HCl (CIP) or norfloxacin (NOR) and phenazopyridine HCl (PHZ). In the first approach, the amplitudes of the first derivative of the ratio spectra were measured at 267 or 287 nm for CIP and at 268 or 291 nm for NOR. PHZ could be directly determined in the presence of CIP or NOR at 405 nm. The calibration graphs were rectilinear over the ranges of 1.0–16.0 µg/mL for CIP or NOR and 1.0–10.0 µg/mL for PHZ. In the second approach, an accurate, reliable and environmentally nontoxic micellar liquid chromatographic (MLC) method was developed. A good chromatographic separation was achieved using a 150 mm × 4.6 mm i.d., 5 µm particle size Spherisorb ODS-2 column. Eco-friendly mobile phase containing 0.12 M sodium dodecyl sulphate, 0.3% triethylamine and 6% n-butanol in 0.02 M orthophosphoric acid of pH 3.0 was pumped at a flow rate of 1 mL/min. Time programmed UV-detection was applied to allow sensitive determination of the studied drugs. The analytes were eluted without interferences in <10 min. Methocarbamol was used as an internal standard. The MLC method was found to be rectilinear over the concentration range of 0.5–20.0 μg/mL for CIP, NOR or PHZ. These optimized and validated methods were successfully applied for the simultaneous analysis of the studied drugs in their synthetic mixtures and co-formulated tablets. Moreover, the second method was further extended to the determination of these drugs in human urine with direct injection and without any pretreatment. PMID:26867555

  9. Determination of imidazole derivatives by micellar electrokinetic chromatography combined with solid-phase microextraction using activated carbon-polymer monolith as adsorbent.

    Science.gov (United States)

    Shih, Yung-Han; Lirio, Stephen; Li, Chih-Keng; Liu, Wan-Ling; Huang, Hsi-Ya

    2016-01-08

    In this study, an effective method for the separation of imidazole derivatives 2-methylimidazole (2-MEI), 4- methylimidazole (4-MEI) and 2-acetyl-4-tetrahydroxybutylimidazole (THI) in caramel colors using cation-selective exhaustive injection and sweeping micellar electrokinetic chromatography (CSEI-sweeping-MEKC) was developed. The limits of detection (LOD) and quantitation (LOQ) for the CSEI-sweeping-MEKC method were in the range of 4.3-80μgL(-1) and 14-270μgL(-1), respectively. Meanwhile, a rapid fabrication activated carbon-polymer (AC-polymer) monolithic column as adsorbent for solid-phase microextraction (SPME) of imidazole colors was developed. Under the optimized SPME condition, the extraction recoveries for intra-day, inter-day and column-to-column were in the range of 84.5-95.1% (<6.3% RSDs), 85.6-96.1% (<4.9% RSDs), and 81.3-96.1% (<7.1% RSDs), respectively. The LODs and LOQs of AC-polymer monolithic column combined with CSEI-sweeping-MEKC method were in the range of 33.4-60.4μgL(-1) and 111.7-201.2μgL(-1), respectively. The use of AC-polymer as SPME adsorbent demonstrated the reduction of matrix effect in food samples such as soft drink and alcoholic beverage thereby benefiting successful determination of trace-level caramel colors residues using CSEI-sweeping-MEKC method. The developed AC-polymer monolithic column can be reused for more than 30 times without any significant loss in the extraction recovery for imidazole derivatives. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Validation of a rapid micellar electrokinetic capillary chromatographic method for the simultaneous determination of isoniazid and pyridoxine hydrochloride in pharmaceutical formulation.

    Science.gov (United States)

    Nemutlu, E; Celebier, M; Uyar, B; Altinöz, S

    2007-07-01

    An efficient and reliable micellar electrokinetic capillary chromatography (MEKC) method has been developed for the simultaneous determination of isoniazid (ISO) and pyridoxine hydrochloride (PYR) in pharmaceutical formulations. A chemometric two level full factorial design approach was used to search for the optimum conditions of separation. Three parameters were selected for this study: the buffer pH, the buffer concentration and sodium dodecyl sulphate (SDS) concentrations. Resolution, peak symmetry and analysis time were established as response. The two analytes were separated within 6 min with the optimized conditions: 50 mM borate buffer, 25 mM SDS pH 7.8, 35 degrees C, at 50 mbar 4s injection and 30 kV by using a fused silica capillary (72 cm effective length, 50 microm i.d.). The detection wavelength was set to 205 nm. Meloxicam was used as internal standard. The method was validated with respect to stability, linearity range, limit of quantitation and detection, precision, accuracy, specificity and robustness. The detection limits of the method were 1.0 microg mL(-1) for ISO and 0.40 microg mL(-1) for PYR and the method was linear at least in the range of 3.0-100 microg mL(-1) for ISO and 1.0-100 microg mL(-1) for PYR with excellent correlation coefficients (0.9995 for ISO and 0.9998 for PYR). Relative standard deviations (R.S.D.s) of the described method ranged between 0.54 and 2.27% for intra-day precision and between 0.65 and 2.69% for inter-day precision. The developed method was applied to the tablet form of ISO and PYR-containing the pharmaceutical preparations and the data were compared with obtained from the standard addition method. No statistically significant difference was found.

  11. Study of the mechanism of acetonitrile stacking and its application for directly combining liquid-phase microextraction with micellar electrokinetic chromatography.

    Science.gov (United States)

    Sun, Jingru; Feng, Jing; Shi, Ludi; Liu, Laping; He, Hui; Fan, Yingying; Hu, Shibin; Liu, Shuhui

    2016-08-26

    Acetonitrile stacking is an online concentration method that is distinctive due to its inclusion of a high proportion of organic solvent in sample matrices. We previously designed a universal methodology for the combination of liquid-phase microextraction (LPME) and capillary electrophoresis (CE) using acetonitrile stacking and micellar electrokinetic chromatography (MEKC) mode, thereby achieving large-volume injection of the diluted LPME extractant and the online concentration. In this report, the methodology was extended to the analysis of highly substituted hydrophobic chlorophenols in wines using diethyl carbonate as the extractant. Additionally, the mechanism of acetonitrile stacking was studied. The results indicated that the combination of LPME and MEKC exhibited good analytical performance: with ∼40-fold concentration by LPME, a 20-cm (33% of the total length) sample plug injection of an eight-fold dilution of diethyl carbonate with the organic solvent-saline solution produced enrichments higher by a factor of 260-791. Limits of qualification ranged from 5.5 to 16.0ng/mL. Acceptable reproducibilities of lower than 1.8% for migration time and 8.6% for peak areas were obtained. A dual stacking mechanism of acetonitrile stacking was revealed, involving transient isotachophoresis plus pH-junction stacking. The latter was associated with a pH shift induced by the presence of acetonitrile. The pseudo-stationary phase (Brij-35) played an important role in reducing the CE running time by weakening the isotachophoretic migration of the analyte ions following Cl(-) ions. The combination of acetonitrile stacking and nonionic micelle-based MEKC appears to be a perfect match for introducing water-immiscible LPME extractants into an aqueous CE system and can thus significantly expand the application of LPME-CE in green analytical chemistry. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Separation and Determination of Four Tanshinones in Danshen and Related Medicinal Plants by Micellar Electrokinetic Chromatography Using Ionic Liquids as Modifier.

    Science.gov (United States)

    Cao, Jiliang; Wei, Jinchao; Xiang, Cheng; Zhang, Mi; Li, Baocai; Wan, Jianbo; Su, Huanxing; Li, Peng

    2016-09-01

    A simple and fast micellar electrokinetic chromatography (MEKC) method using ionic liquids as modifier was established for simultaneous determination of four hydrophobic tanshinones, including dihydrotanshinone I ( 1: ), cryptotanshinone ( 2: ), tanshinone I ( 3: ) and tanshinone IIA ( 4: ), in Danshen and related medicinal plants. In normal MEKC using sodium dodecyl sulfate (SDS) as surfactant and organic solvents as additives, the four tanshinones, especially cryptotanshinone and tanshinone I, could not be well separated. Fortunately, further addition of ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF4) resulted in a baseline separation of these four analytes. After an optimization study, 10 mM borax-10 mM SDS-10 mM [bmim]BF4 containing 15% acetonitrile (v/v) at pH 9.6 was adopted as the running buffer to complete the separation within 16 min at the voltage of 25 kV, temperature of 25°C and detection wavelength of 254 nm. The relative standard deviations of migration time and peak area were in the range of 0.62-2.21 and 1.33-3.90%, respectively, indicating the good repeatability of the developed method. This method was extensively validated by evaluating the linearity (R(2) ≥ 0.9992), limits of detection (0.75-1.11 μg mL(-1)), limits of quantification (2.26-3.32 μg mL(-1)) and recovery (96.11-103.74%). Under the optimum conditions, samples of Danshen and related medicinal plants were well analyzed with high separation efficiency. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  13. Application of an aqueous two-phase micellar system to extract bromelain from pineapple (Ananas comosus) peel waste and analysis of bromelain stability in cosmetic formulations.

    Science.gov (United States)

    Spir, Lívia Genovez; Ataide, Janaína Artem; De Lencastre Novaes, Letícia Celia; Moriel, Patrícia; Mazzola, Priscila Gava; De Borba Gurpilhares, Daniela; Silveira, Edgar; Pessoa, Adalberto; Tambourgi, Elias Basile

    2015-01-01

    Bromelain is a set of proteolytic enzymes found in pineapple (Ananas comosus) tissues such as stem, fruit and leaves. Because of its proteolytic activity, bromelain has potential applications in the cosmetic, pharmaceutical, and food industries. The present study focused on the recovery of bromelain from pineapple peel by liquid-liquid extraction in aqueous two-phase micellar systems (ATPMS), using Triton X-114 (TX-114) and McIlvaine buffer, in the absence and presence of electrolytes CaCl2 and KI; the cloud points of the generated extraction systems were studied by plotting binodal curves. Based on the cloud points, three temperatures were selected for extraction: 30, 33, and 36°C for systems in the absence of salts; 40, 43, and 46°C in the presence of KI; 24, 27, and 30°C in the presence of CaCl2 . Total protein and enzymatic activities were analyzed to monitor bromelain. Employing the ATPMS chosen for extraction (0.5 M KI with 3% TX-114, at pH 6.0, at 40°C), the bromelain extract stability was assessed after incorporation into three cosmetic bases: an anhydrous gel, a cream, and a cream-gel formulation. The cream-gel formulation presented as the most appropriate base to convey bromelain, and its optimal storage conditions were found to be 4.0 ± 0.5°C. The selected ATPMS enabled the extraction of a biomolecule with high added value from waste lined-up in a cosmetic formulation, allowing for exploration of further cosmetic potential. © 2015 American Institute of Chemical Engineers.

  14. Enantioselective micellar electrokinetic chromatography of dl-amino acids using (+)-1-(9-fluorenyl)-ethyl chloroformate derivatization and UV-induced fluorescence detection.

    Science.gov (United States)

    Prior, Amir; van de Nieuwenhuijzen, Erik; de Jong, Gerhardus J; Somsen, Govert W

    2018-05-22

    Chiral analysis of dl-amino acids was achieved by micellar electrokinetic chromatography coupled with UV-excited fluorescence detection. The fluorescent reagent (+)-1-(9-fluorenyl)ethyl chloroformate was employed as chiral amino acid derivatizing agent and sodium dodecyl sulfate served as pseudo-stationary phase for separating the formed amino acid diastereomers. Sensitive analysis of (+)-1-(9-fluorenyl)ethyl chloroformate-amino acids was achieved applying a xenon-mercury lamp for ultraviolet excitation, and a spectrograph and charge-coupled device for wavelength-resolved emission detection. Applying signal integration over a 30-nm emission wavelength interval, signal-to-noise ratios for derivatized amino acids were up to 23 times higher as obtained using a standard photomultiplier for detection. The background electrolyte composition (electrolyte, pH, sodium dodecyl sulfate concentration, and organic solvent) was studied in order to attain optimal chemo- and enantioseparation. Enantioseparation of twelve proteinogenic dl-amino acids was achieved with chiral resolutions between 1.2 and 7.9, and detection limits for most derivatized amino acids in the 13-60 nM range (injected concentration). Linearity (coefficients of determination > 0.985) and peak-area and migration-time repeatabilities (relative standard deviations lower than 2.6 and 1.9%, respectively) were satisfactory. The employed fluorescence detection system provided up to 100-times better signal-to-noise ratios for (+)-1-(9-fluorenyl)ethyl chloroformate-amino acids than ultraviolet absorbance detection, showing good potential for d-amino acid analysis. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  15. Naturalising Representational Content

    Science.gov (United States)

    Shea, Nicholas

    2014-01-01

    This paper sets out a view about the explanatory role of representational content and advocates one approach to naturalising content – to giving a naturalistic account of what makes an entity a representation and in virtue of what it has the content it does. It argues for pluralism about the metaphysics of content and suggests that a good strategy is to ask the content question with respect to a variety of predictively successful information processing models in experimental psychology and cognitive neuroscience; and hence that data from psychology and cognitive neuroscience should play a greater role in theorising about the nature of content. Finally, the contours of the view are illustrated by drawing out and defending a surprising consequence: that individuation of vehicles of content is partly externalist. PMID:24563661

  16. Qualitative Content Analysis

    OpenAIRE

    Philipp Mayring

    2000-01-01

    The article describes an approach of systematic, rule guided qualitative text analysis, which tries to preserve some methodological strengths of quantitative content analysis and widen them to a concept of qualitative procedure. First the development of content analysis is delineated and the basic principles are explained (units of analysis, step models, working with categories, validity and reliability). Then the central procedures of qualitative content analysis, inductive development of ca...

  17. A Lipophilic IR-780 Dye-Encapsulated Zwitterionic Polymer-Lipid Micellar Nanoparticle for Enhanced Photothermal Therapy and NIR-Based Fluorescence Imaging in a Cervical Tumor Mouse Model

    Directory of Open Access Journals (Sweden)

    Santhosh Kalash Rajendrakumar

    2018-04-01

    Full Text Available To prolong blood circulation and avoid the triggering of immune responses, nanoparticles in the bloodstream require conjugation with polyethylene glycol (PEG. However, PEGylation hinders the interaction between the nanoparticles and the tumor cells and therefore limits the applications of PEGylated nanoparticles for therapeutic drug delivery. To overcome this limitation, zwitterionic materials can be used to enhance the systemic blood circulation and tumor-specific delivery of hydrophobic agents such as IR-780 iodide dye for photothermal therapy. Herein, we developed micellar nanoparticles using the amphiphilic homopolymer poly(12-(methacryloyloxydodecyl phosphorylcholine (PCB-lipid synthesized via reversible addition–fragmentation chain transfer (RAFT polymerization. The PCB-lipid can self-assemble into micelles and encapsulate IR-780 dye (PCB-lipid–IR-780. Our results demonstrated that PCB-lipid–IR-780 nanoparticle (NP exhibited low cytotoxicity and remarkable photothermal cytotoxicity to cervical cancer cells (TC-1 upon near-infrared (NIR laser irradiation. The biodistribution of PCB-lipid–IR-780 showed higher accumulation of PCB-lipid–IR-780 than that of free IR-780 in the TC-1 tumor. Furthermore, following NIR laser irradiation of the tumor region, the PCB-lipid–IR-780 accumulated in the tumor facilitated enhanced tumor ablation and subsequent tumor regression in the TC-1 xenograft model. Hence, these zwitterionic polymer-lipid hybrid micellar nanoparticles show great potential for cancer theranostics and might be beneficial for clinical applications.

  18. Hydroponics: Content and Rationale

    Science.gov (United States)

    Ernst, Jeremy V.; Busby, Joe R.

    2009-01-01

    Technology education has the means of becoming the catalyst for integrated content and curricula, especially in core academic areas, such as science and mathematics, where it has been found difficult to incorporate other subject matter. Technology is diverse enough in nature that it can be addressed by a variety of content areas, serving as a true…

  19. Branded content infantil

    OpenAIRE

    Raúl RODRÍGUEZ-FERRÁNDIZ

    2017-01-01

    Reseña del libro Bajo la influencia del branded content. Efectos de los contenidos de marca en niños y jóvenes. Review of the book Bajo la influencia del branded content. Efectos de los contenidos de marca en niños y jóvenes.

  20. Branded content infantil

    Directory of Open Access Journals (Sweden)

    Raúl RODRÍGUEZ-FERRÁNDIZ

    2017-01-01

    Full Text Available Reseña del libro Bajo la influencia del branded content. Efectos de los contenidos de marca en niños y jóvenes. Review of the book Bajo la influencia del branded content. Efectos de los contenidos de marca en niños y jóvenes.

  1. Print advertising: vivid content

    NARCIS (Netherlands)

    Fennis, B.M.; Das, E.; Fransen, M.L.

    2012-01-01

    The present research examines the effects of vivid ad content in two types of appeal in print ads as a function of individual differences in chronically experienced vividness of visual imagery. For informational ads for a functional product, vivid ad content strongly affected individuals high in

  2. Print advertising : Vivid content

    NARCIS (Netherlands)

    Fennis, B.M.; Das, E.H.H.J.; Fransen, M.L.

    The present research examines the effects of vivid ad content in two types of appeal in print ads as a function of individual differences in chronically experienced vividness of visual imagery. For informational ads for a functional product, vivid ad content strongly affected individuals high in

  3. Qualitative Content Analysis

    OpenAIRE

    Satu Elo; Maria Kääriäinen; Outi Kanste; Tarja Pölkki; Kati Utriainen; Helvi Kyngäs

    2014-01-01

    Qualitative content analysis is commonly used for analyzing qualitative data. However, few articles have examined the trustworthiness of its use in nursing science studies. The trustworthiness of qualitative content analysis is often presented by using terms such as credibility, dependability, conformability, transferability, and authenticity. This article focuses on trustworthiness based on a review of previous studie...

  4. Social video content delivery

    CERN Document Server

    Wang, Zhi; Zhu, Wenwu

    2016-01-01

    This brief presents new architecture and strategies for distribution of social video content. A primary framework for socially-aware video delivery and a thorough overview of the possible approaches is provided. The book identifies the unique characteristics of socially-aware video access and social content propagation, revealing the design and integration of individual modules that are aimed at enhancing user experience in the social network context. The change in video content generation, propagation, and consumption for online social networks, has significantly challenged the traditional video delivery paradigm. Given the massive amount of user-generated content shared in online social networks, users are now engaged as active participants in the social ecosystem rather than as passive receivers of media content. This revolution is being driven further by the deep penetration of 3G/4G wireless networks and smart mobile devices that are seamlessly integrated with online social networking and media-sharing s...

  5. Learning Content Management Systems

    Directory of Open Access Journals (Sweden)

    Tache JURUBESCU

    2008-01-01

    Full Text Available The paper explains the evolution of e-Learning and related concepts and tools and its connection with other concepts such as Knowledge Management, Human Resources Management, Enterprise Resource Planning, and Information Technology. The paper also distinguished Learning Content Management Systems from Learning Management Systems and Content Management Systems used for general web-based content. The newest Learning Content Management System, very expensive and yet very little implemented is one of the best tools that helps us to cope with the realities of the 21st Century in what learning concerns. The debates over how beneficial one or another system is for an organization, can be driven by costs involved, efficiency envisaged, and availability of the product on the market.

  6. Building and Contents Insurance.

    Science.gov (United States)

    Freese, William C.

    Insurance coverage of school buildings and contents is becoming increasingly difficult to obtain, and increases of 50 percent or more in the premium are not uncommon. Methods of reducing premium increases are outlined in this speech. (MLF)

  7. Selenium content of mushrooms.

    Science.gov (United States)

    Stijve, T

    1977-07-29

    The selenium contents of 83 species of wild mushrooms were determined by oxygen combustion of the sample, followed by conversion of selenite to bromopiazselenol and final estimation by electron capture gas-liquid chromatography. Selenium concentration were found to range from 0.012-20.0 mg/kg dry weight. Selenium content was species-dependent. High concentrations were found in Agaricaceae and in certain Boletaceae of the genus Tubiporus, whereas in Russulaceae, Amanitaceae and Cantharellaceae selenium-rich species were absent or rare. Ascomycetes and all mushrooms growing on wood had a very low selenium content. The highest selenium concentrations (up to 20 ppm) were found in Boletus (Tubiporus) edulis, a most popular edible mushroom. Analyses of various parts of carpophores of B. edulis, Suillus luteus and Amanita muscaria indicate that in all three species the stalk contains less selenium than the fleshy part of the cap. In Boletus and Suillus the highest selenium content was found in the tubes.

  8. METHODS OF CONTENTS CURATOR

    Directory of Open Access Journals (Sweden)

    V. Kukharenko

    2013-03-01

    Full Text Available Content curated - a new activity (started in 2008 qualified network users with process large amounts of information to represent her social network users. To prepare content curators developed 7 weeks distance course, which examines the functions, methods and tools curator. Courses showed a significant relationship success learning on the availability of advanced personal learning environment and the ability to process and analyze information.

  9. Qualitative Content Analysis

    Directory of Open Access Journals (Sweden)

    Satu Elo

    2014-02-01

    Full Text Available Qualitative content analysis is commonly used for analyzing qualitative data. However, few articles have examined the trustworthiness of its use in nursing science studies. The trustworthiness of qualitative content analysis is often presented by using terms such as credibility, dependability, conformability, transferability, and authenticity. This article focuses on trustworthiness based on a review of previous studies, our own experiences, and methodological textbooks. Trustworthiness was described for the main qualitative content analysis phases from data collection to reporting of the results. We concluded that it is important to scrutinize the trustworthiness of every phase of the analysis process, including the preparation, organization, and reporting of results. Together, these phases should give a reader a clear indication of the overall trustworthiness of the study. Based on our findings, we compiled a checklist for researchers attempting to improve the trustworthiness of a content analysis study. The discussion in this article helps to clarify how content analysis should be reported in a valid and understandable manner, which would be of particular benefit to reviewers of scientific articles. Furthermore, we discuss that it is often difficult to evaluate the trustworthiness of qualitative content analysis studies because of defective data collection method description and/or analysis description.

  10. Factors stimulating content marketing

    Directory of Open Access Journals (Sweden)

    Naser Azad

    2016-02-01

    Full Text Available This paper presents an empirical investigation to determine factors influencing on content marketing in banking industry. The study designs a questionnaire consists of 40 questions in Likert scale and distributes it among 550 randomly selected regular customers of Bank Mellat in city of Tehran, Iran and 400 properly filled questionnaires are collected. Cronbach alphas for all components of the survey are well above desirable level. Using principle component analysis with Varimax rotation, the study has determined six factors influencing the most on content marketing including organization, details, having new ideas, quality, sensitivity and power while the last component contains only two subcomponents and is removed from the study.

  11. An equilibrium model for ligand-modified micellar-enhanced ultrafiltration. Selective separation of metal ions using iminoacetic substituted polyamines and a theoretical model for the titration behavior of polyamines

    Energy Technology Data Exchange (ETDEWEB)

    Dharmawardana, Udeni Rajaratna [Univ. of Oklahoma, Norman, OK (United States)

    1992-01-01

    This thesis consists of three chapters. Chapter 1, An equilibrium model for ligand-modified micellar-enhanced ultrafiltration, describes a theoretical model and experimental investigations which used the semi-equilibrium-dialysis method with N-n-dodecyl iminodiacetic acid as the ligand. In Chapter 2, Selective separation of metal ions using iminoacetic substituted polyamines, polyamines with a substituted ligand group are synthesized and used in investigating selective separation of copper ions from aqueous solution. In Chapter 3, A theoretical model for the titration behavior of polyamines, a novel approach to explain the titration behavior of polymeric amines based on the binding behavior of counterions is described. The application of this study is to the investigation of inexpensive and efficient methods of industrial waste water treatment.

  12. The Development of a New Inhibition Kinetic Spectrophotometric Method for the Determination of Phenylhydrazine Based on its Inhibitory Effect on Oxidation of Methyl Red by Bromate in Micellar Medium

    Directory of Open Access Journals (Sweden)

    Mohsen Keyvanfard

    2010-01-01

    Full Text Available A new, simple, sensitive and selective kinetic spectrophotometric method was developed for the determination of trace amounts of phenylhydrazine over the range of 0.02-0.30 μg/mL. The method is based on the inhibitory effect of phenylhydrazine on the oxidation of methyl red by bromate in acidic and micellar medium. The reaction was monitored spectrophotometrically by measuring the decrease in absorbance of methyl red at 518 nm with a fixed-time 0.5–2.0 min from initiation of the reaction..The relative standard deviation of 0.08 and 0.2 μg/mL phenylhydrazine was 1.7 and 2.4%, respectively. The method was applied to the determination of phenylhydrazine in water samples.

  13. Matrix-assisted laser desorption/ionization mass spectrometric analysis of poly(3,4-ethylenedioxythiophene) in solid-state dye-sensitized solar cells: comparison of in situ photoelectrochemical polymerization in aqueous micellar and organic media.

    Science.gov (United States)

    Zhang, Jinbao; Ellis, Hanna; Yang, Lei; Johansson, Erik M J; Boschloo, Gerrit; Vlachopoulos, Nick; Hagfeldt, Anders; Bergquist, Jonas; Shevchenko, Denys

    2015-04-07

    Solid-state dye-sensitized solar cells (sDSCs) are devoid of such issues as electrolyte evaporation or leakage and electrode corrosion, which are typical for traditional liquid electrolyte-based DSCs. Poly(3,4-ethylenedioxythiophene) (PEDOT) is one of the most popular and efficient p-type conducting polymers that are used in sDSCs as a solid-state hole-transporting material. The most convenient way to deposit this insoluble polymer into the dye-sensitized mesoporous working electrode is in situ photoelectrochemical polymerization. Apparently, the structure and the physicochemical properties of the generated conducting polymer, which determine the photovoltaic performance of the corresponding solar cell, can be significantly affected by the preparation conditions. Therefore, a simple and fast analytical method that can reveal information on polymer chain length, possible chemical modifications, and impurities is strongly required for the rapid development of efficient solar energy-converting devices. In this contribution, we applied matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) for the analysis of PEDOT directly on sDSCs. It was found that the PEDOT generated in aqueous micellar medium possesses relatively shorter polymeric chains than the PEDOT deposited from an organic medium. Furthermore, the micellar electrolyte promotes a transformation of one of the thiophene terminal units to thiophenone. The introduction of a carbonyl group into the PEDOT molecule impedes the growth of the polymer chain and reduces the conductivity of the final polymer film. Both the simplicity of sample preparation (only application of the organic matrix onto the solar cell is needed) and the rapidity of analysis hold the promise of making MALDI MS an essential tool for the physicochemical characterization of conducting polymer-based sDSCs.

  14. Trustworthy content push

    OpenAIRE

    Kuntze, Nicolai; Schmidt, Andreas U.

    2006-01-01

    Delivery of content to mobile devices gains increasing importance in industrial environments to support employees in the field. An important application are e-mail push services like the fashionable Blackberry. These systems are facing security challenges regarding data transport to, and storage of the data on the end user equipment. The emerging Trusted Computing technology offers new answers to these open questions.

  15. LCS Content Document Application

    Science.gov (United States)

    Hochstadt, Jake

    2011-01-01

    My project at KSC during my spring 2011 internship was to develop a Ruby on Rails application to manage Content Documents..A Content Document is a collection of documents and information that describes what software is installed on a Launch Control System Computer. It's important for us to make sure the tools we use everyday are secure, up-to-date, and properly licensed. Previously, keeping track of the information was done by Excel and Word files between different personnel. The goal of the new application is to be able to manage and access the Content Documents through a single database backed web application. Our LCS team will benefit greatly with this app. Admin's will be able to login securely to keep track and update the software installed on each computer in a timely manner. We also included exportability such as attaching additional documents that can be downloaded from the web application. The finished application will ease the process of managing Content Documents while streamlining the procedure. Ruby on Rails is a very powerful programming language and I am grateful to have the opportunity to build this application.

  16. Tourist-created Content

    DEFF Research Database (Denmark)

    Munar, Ana Maria

    2011-01-01

    study of social media sites and destination brands, relying on qualitative research methods, content analysis and field research. Findings – Tourists are largely contributing to destination image formation, while avoiding the use of the formal elements of the brands. The most popular strategies used...

  17. Loser Generated Content

    DEFF Research Database (Denmark)

    Petersen, Søren Mørk

    2008-01-01

    In this article [ 1 ] some of the critical aspects of Web 2.0 are mapped in relation to labor and the production of user generated content. For many years the Internet was considered an apt technology for subversion of capitalism by the Italian post–Marxists. What we have witnessed, however...

  18. Content Maps: A Teaching and Assessment Tool for Content Knowledge

    Science.gov (United States)

    Ward, Phillip; Lehwald, Harry; Lee, Yun Soo

    2015-01-01

    Developing content knowledge in teachers presents a constant challenge for teacher educators. This article introduces a teaching and assessment tool called a "content map," which allows teacher educators, teachers, and coaches to conceptualize the scope, sequence, and relational characteristics of the content being taught. Content maps…

  19. Content Documents Management

    Science.gov (United States)

    Muniz, R.; Hochstadt, J.; Boelke J.; Dalton, A.

    2011-01-01

    The Content Documents are created and managed under the System Software group with. Launch Control System (LCS) project. The System Software product group is lead by NASA Engineering Control and Data Systems branch (NEC3) at Kennedy Space Center. The team is working on creating Operating System Images (OSI) for different platforms (i.e. AIX, Linux, Solaris and Windows). Before the OSI can be created, the team must create a Content Document which provides the information of a workstation or server, with the list of all the software that is to be installed on it and also the set where the hardware belongs. This can be for example in the LDS, the ADS or the FR-l. The objective of this project is to create a User Interface Web application that can manage the information of the Content Documents, with all the correct validations and filters for administrator purposes. For this project we used one of the most excellent tools in agile development applications called Ruby on Rails. This tool helps pragmatic programmers develop Web applications with Rails framework and Ruby programming language. It is very amazing to see how a student can learn about OOP features with the Ruby language, manage the user interface with HTML and CSS, create associations and queries with gems, manage databases and run a server with MYSQL, run shell commands with command prompt and create Web frameworks with Rails. All of this in a real world project and in just fifteen weeks!

  20. Content Marketing Practices in Finland

    OpenAIRE

    Suuronen, Toni

    2016-01-01

    The purpose of this study is to draw attention to increasingly important business phenomenon of content marketing. This paper defines content marketing, identifies its key elements and phases, and explores content marketing practices. The theorethical part is based on Pam Didner's 4P model that describes the stages of content marketing cycle: plan, produce, promote and perfect. The empirical part of the study is based on semi-structured interviews of seasoned content marketing professionals t...

  1. Determining gold content

    International Nuclear Information System (INIS)

    Clayton, C.G.; Wormald, M.R.

    1981-01-01

    A method for determining the gold content of a material, comprises irradiating a body of the material with neutrons and determining the intensity of γ-rays having an energy of 279 keV arising from the reaction 179 Au(nn') 179 Au → 279 keV. The apparatus has means for conveying the materials past an assembly, which has a neutron source, which does not produce neutrons having sufficient energy to excite fast neutron reactions in non-auriferous constituents. (author)

  2. Personalized professional content recommendation

    Science.gov (United States)

    Xu, Songhua

    2015-10-27

    A personalized content recommendation system includes a client interface configured to automatically monitor a user's information data stream transmitted on the Internet. A hybrid contextual behavioral and collaborative personal interest inference engine resident to a non-transient media generates automatic predictions about the interests of individual users of the system. A database server retains the user's personal interest profile based on a plurality of monitored information. The system also includes a server programmed to filter items in an incoming information stream with the personal interest profile and is further programmed to identify only those items of the incoming information stream that substantially match the personal interest profile.

  3. The role of content marketing in social media content communities

    OpenAIRE

    Charmaine du Plessis

    2017-01-01

    Background: Content marketing has become a leading marketing technique in digital marketing communication and uses the point of view of consumers to build relationships by creating and sharing engaging content in social media that enhance their daily lives. Existing research on social media communities has focused mainly on social media marketing and virtual brand community perspectives while content marketing’s valuable and unobtrusive role in social media content communities has largely bee...

  4. Micellar solubilization of ibuprofen: influence of surfactant head groups on the extent of solubilization Solubilização micelar do ibuprofeno: influência do grupo polar dos tensoativos no grau de solubilização

    Directory of Open Access Journals (Sweden)

    Carlota O. Rangel-Yagui

    2005-06-01

    Full Text Available An important property of micelles with particular significance in pharmacy is their ability to increase the solubility of poorly soluble drugs in water, thus increasing their bioavailability. In this work, the solubilization of ibuprofen (IBU was studied in micellar solutions of three surfactants possessing the same hydrocarbon tail but different hydrophilic head groups, namely sodium dodecyl sulphate (SDS, dodecyltrimethylammonium bromide (DTAB, and n-dodecyl octa(ethylene oxide (C12EO8. The results showed that, irrespective of the surfactant type, the solubility of IBU increased linearly with increasing surfactant concentration, as a consequence of the association between the drug and the micelles. The 80 mM DTAB and the 80 mM C12EO8 micellar solutions resulted in a 16-fold increase in solubility of IBU when compared to the buffer solution, whereas the 80 mM SDS micellar solution resulted in a 5.5-fold increase in IBU solubility. The highest value of molar solubilization capacity (chi was obtained with DTAB, chi = 0.97, followed by C12EO8 ,chi = 0.72, and finally SDS, chi = 0.23. However, due to the stronger tendency of the nonionic surfactant in forming micelles in solution, at the same surfactant concentration, we obtained the same solubility of IBU in both DTAB and C12EO8.Uma propriedade importante das micelas, do ponto de vista farmacêutico, refere-se ao potencial destas em solubilizar fármacos pouco solúveis em água, aumentando sua biodisponibilidade. No presente trabalho, estudou-se a solubilização de ibuprofeno (IBU em soluções micelares constituídas de três tensoativos apresentando a mesma cauda apolar, porém diferentes grupos hidrofílicos. Os tensoativos estudados foram dodecil sulfato de sódio (SDS, brometo de dodeciltrimetilamônio (DTAB e óxido de n-dodecil octaetileno (C12EO8. De acordo com os resultados obtidos, a solubilidade do IBU aumentou linearmente com o aumento da concentração de todos os tensoativos

  5. Free Flowing Content

    DEFF Research Database (Denmark)

    Cass, Andrew Knox; Kravchenko, Mariia

    2017-01-01

    Higher education institutions are moving to exploit information andcommunication technologies by increasing the use of videos both online and inclass. This is led, by definition, by ‘early adopters’ and most of the research intothis process reflects this. Increasingly, institutions are making...... strategic decisionsto move courses online however, some teachers involved are not well equippedto transition. The barriers are reported to be time constraints and a lack offamiliarity with the technology to make video. Also, there is a fear of the‘presented self’ where teachers may initially resent the idea...... do not secure theintegrity of the learning. This paper sets out the methods used to assist teacherstake the maximum benefit of their existing content as presentation style lecturesand utilize them for video recording suitable for both flipped and online classes.A central theme is removing the fear...

  6. Nostalgia: content, triggers, functions.

    Science.gov (United States)

    Wildschut, Tim; Sedikides, Constantine; Arndt, Jamie; Routledge, Clay

    2006-11-01

    Seven methodologically diverse studies addressed 3 fundamental questions about nostalgia. Studies 1 and 2 examined the content of nostalgic experiences. Descriptions of nostalgic experiences typically featured the self as a protagonist in interactions with close others (e.g., friends) or in momentous events (e.g., weddings). Also, the descriptions contained more expressions of positive than negative affect and often depicted the redemption of negative life scenes by subsequent triumphs. Studies 3 and 4 examined triggers of nostalgia and revealed that nostalgia occurs in response to negative mood and the discrete affective state of loneliness. Studies 5, 6, and 7 investigated the functional utility of nostalgia and established that nostalgia bolsters social bonds, increases positive self-regard, and generates positive affect. These findings demarcate key landmarks in the hitherto uncharted research domain of nostalgia.

  7. Radioactivity content of books

    International Nuclear Information System (INIS)

    Lalit, B.Y.; Shukla, V.K.; Ramachandran, T.V.

    1981-01-01

    The natural and fallout radioactivity was measured in a large number of books produced in various countries after 1955. Results of these measurements showed that the books contained radioactivity due to fallout 137 Cs and 226 Ra, 228 Th and 40 K radioisotopes of primordial origin. Books printed in the U.S.A. had low radioactivity of 40K and 226 Ra origin compared to books printed in the European subcontinent. Books printed during high fallout rate (1962-64) or thereafter did not exhibit any significantly higher 137 Cs levels. The maximum radiation dose to the eyes calculated for the radioactivity content of the books was 0.8 μR/hr and the minimum was 0.07 μR/hr; most of the books were in the range 0.3-0.5 μR/hr. (U.K.)

  8. Multimedia content analysis

    CERN Document Server

    Ohm, Jens

    2016-01-01

    This textbook covers the theoretical backgrounds and practical aspects of image, video and audio feature expression, e.g., color, texture, edge, shape, salient point and area, motion, 3D structure, audio/sound in time, frequency and cepstral domains, structure and melody. Up-to-date algorithms for estimation, search, classification and compact expression of feature data are described in detail. Concepts of signal decomposition (such as segmentation, source tracking and separation), as well as composition, mixing, effects, and rendering, are discussed. Numerous figures and examples help to illustrate the aspects covered. The book was developed on the basis of a graduate-level university course, and most chapters are supplemented by problem-solving exercises. The book is also a self-contained introduction both for researchers and developers of multimedia content analysis systems in industry. .

  9. The role of content marketing in social media content communities

    Directory of Open Access Journals (Sweden)

    Charmaine du Plessis

    2017-10-01

    Full Text Available Background: Content marketing has become a leading marketing technique in digital marketing communication and uses the point of view of consumers to build relationships by creating and sharing engaging content in social media that enhance their daily lives. Existing research on social media communities has focused mainly on social media marketing and virtual brand community perspectives while content marketing’s valuable and unobtrusive role in social media content communities has largely been overlooked. Objective: The purpose of this article was to investigate content marketing’s role in social media content communities to engage with the target audience in an innate manner. Method: This study made use of a directed, inductive content analysis of 51 practitioner documents relating to business-to-consumer content marketing practices to add another perspective to existing research on communities in social media. The content analysis was facilitated by using QDA Miner, a widely adopted and reliable qualitative data analysis software programme. Results: Three categories emerged from the data namely building content communities, platform-specific content and understanding channels. These categories provide sufficient evidence of how brands make use of social media content communities to connect with the target audience in an unobtrusive manner, in addition to being present in virtual brand communities. Conclusion: The findings make several contributions to the existing literature. Firstly, it provides a clearer distinction between brand and social media content communities. Secondly, it extends conceptions about social media communities to include content communities and, thirdly, it provides sufficient evidence of how content marketing could benefit a brand by naturally becoming part of social media conversations.

  10. Solubilisation des hydrocarbures dans les solutions micellaires Influence de la structure et de la masse moléculaire Solubilization of Hydrocarbons in Micellar Solutions Influence of Structure and Molecular Weight

    Directory of Open Access Journals (Sweden)

    Baviere M.

    2006-11-01

    (paraffines, résines, asphaltènes sur les propriétés interfaciales, d'une part avec le brut de Daqing, pour effectuer des essais complémentaires, d'autre part avec des constituants modèles en solution dans un solvant approprié. Optimizing the formulation of micellar surfactant solutions used for enhanced oil recovery consists in obtaining interfacial tensions that are as low as possible in multiphase systems resulting from the mixing of the injected solution with formation fluids. The solubilization of hydrocarbons by the micellar phases of such systems is linked directly to the interfacial efficiency of surfactants. Indeed, as has been shown by numerous research projects such as the one by Reed and Healy [1], the amount of hydrocarbons solubilized by the surfactant is all the greater as the interfacial tension between the micellar phase and the hydrocarbons is low. This solubilization depends in particular, although to a great extent, on the nature of the hydrocarbons or, for the processes we are concerned with here, of the hydrocarbon mixtures encountered [181. Likewise, the criteria generally used in applying the process to a reservoir may also be fulfilled (temperature, salinity of the water, viscosity of the oil, nature and permeability of the rock, whereas the chemical nature of the oil turns out to be responsible for very mediocre efficiency. Hence this insufficiency of criteria is revealed for relatively heavy oils such as the oil in the Daqing field in China, for which production may still depend on this recovery method, a priori. The solubilization of this oil by the surfactants normally used is extremely reduced and may perhaps even by almost nil. This particularly unfavorable behavior has brought out the need of specifying selection criteria for fields from the standpoint of the nature of the oil, so as to be able to assess the quality of a crude oil and to detect possible difficulties in applying the process-diff iculties linked to the composition of the

  11. List of Content

    Directory of Open Access Journals (Sweden)

    IJRED Editorial

    2013-02-01

    Full Text Available CONTENTS OF ARTICLES PAGEPassive Design of Buildings for Extreme Weather EnvironmentS.N. Al-Zubaidy, S. Tokbolat, R. Tokpatayeva 1-11 Economic Impact of CDM Implementation through Alternate Energy Resource SubstitutionK.J. Sreekanth, S. Jayaraj, N. Sudarsan 13-18 Implications of Charcoal Briquette Produced by Local Communities on Livelihoods and Environment in Nairobi KenyaMary Njenga, A Yonemitsu, N Karanjaa, M Iiyama, J Kithinji, M Dubbeling C Sundberge, R R Jamnadass 19-29 A Novel Design of Multi-Chambered Biomass BatteryK. Sudhakar, R. Ananthakrishnan, A. Goyal, H.K. Darji 31-34 Power Quality Improvement Wind Energy System Using Cascaded Multilevel InverterJ.S. Sathiyanarayanan, A. S. Kumar 35-43 Solar PV Lighting and Studying after Sunset: Analysis of Micro-benefits in Off-grid Rural GhanaGeorge Y. Obeng 45-51 Innovative Green Technology for Sustainable Industrial Estate DevelopmentR. Hadiwijoyo, P Purwanto, Sudharto P Hadi 53-58 Empowering Distributed Solar PV Energy For Malaysian Rural Housing: Towards Energy Security And Equitability Of Rural CommunitiesN.A. Ahmad, H. Byrd 59-68

  12. Content validity and its estimation

    Directory of Open Access Journals (Sweden)

    Yaghmale F

    2003-04-01

    Full Text Available Background: Measuring content validity of instruments are important. This type of validity can help to ensure construct validity and give confidence to the readers and researchers about instruments. content validity refers to the degree that the instrument covers the content that it is supposed to measure. For content validity two judgments are necessary: the measurable extent of each item for defining the traits and the set of items that represents all aspects of the traits. Purpose: To develop a content valid scale for assessing experience with computer usage. Methods: First a review of 2 volumes of International Journal of Nursing Studies, was conducted with onlyI article out of 13 which documented content validity did so by a 4-point content validity index (CV! and the judgment of 3 experts. Then a scale with 38 items was developed. The experts were asked to rate each item based on relevance, clarity, simplicity and ambiguity on the four-point scale. Content Validity Index (CVI for each item was determined. Result: Of 38 items, those with CVIover 0.75 remained and the rest were discarded reSulting to 25-item scale. Conclusion: Although documenting content validity of an instrument may seem expensive in terms of time and human resources, its importance warrants greater attention when a valid assessment instrument is to be developed. Keywords: Content Validity, Measuring Content Validity

  13. Integration of vanadium-mixed addenda Dawson heteropolytungstate within poly(3,4-ethylenedioxythiophene) and poly(2,2'-bithiophene) films by electrodeposition from the nonionic micellar aqueous medium

    Energy Technology Data Exchange (ETDEWEB)

    Goral, Monika [Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw (Poland); Jouini, Mohamed, E-mail: jouini@univ-paris-diderot.f [Laboratory Interfaces, Traitements, Organisation et DYnamique des Systemes (ITODYS) UMR 7086, Universite Paris Diderot Paris 7 Batiment Lavoisier, 15 Rue Jean Antoine de Baif, 75205 Paris Cedex 13 (France); Perruchot, Christian [Laboratory Interfaces, Traitements, Organisation et DYnamique des Systemes (ITODYS) UMR 7086, Universite Paris Diderot Paris 7 Batiment Lavoisier, 15 Rue Jean Antoine de Baif, 75205 Paris Cedex 13 (France); Miecznikowski, Krzysztof; Rutkowska, Iwona A. [Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw (Poland); Kulesza, Pawel J., E-mail: pkulesza@chem.uw.edu.p [Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw (Poland)

    2011-04-01

    A comparative study describing immobilization of the Dawson type mixed addenda heteropolyanion, [P{sub 2}W{sub 17}VO{sub 62}]{sup 8-} into conducting polymer films of poly(3,4-ethylenedioxythiophene), PEDOT, and poly(2,2'-bithiophene), PBT, is reported. Electrosynthesis of these hybrid films was performed using a micellar aqueous solution of the nonionic surfactant, polyethylene glycol tert-octylphenyl ether (Triton X-100). Deposited composite films were characterised electrochemically and, on the whole, they exhibited fast electron transfer (ET) properties and relatively high stability towards continuous potential cycling in acidic media. In particular, PEDOT composite showed relatively faster ET properties in comparison to PBT composite. Their permeability was investigated in the presence of cationic and anionic redox probes. Our results implied good mediating capabilities of the [P{sub 2}W{sub 17}V{sup 4+}O{sub 62}]{sup 8-} anion (within the [P{sub 2}W{sub 17}V{sup 4+}O{sub 62}]{sup 8-}-PEDOT hybrid film) towards the iron (III) reduction. The specific electrocatalytic (reductive) capabilities of hybrid films were also studied by probing the reduction of bromate. The films were further characterised by X-ray photoelectron spectroscopy to establish their interfacial elemental composition. Moreover, their surface morphology was imaged by atomic force microscopy and scanning electron microscopy. Results have shown that physicochemical properties of the investigated hybrid films were affected by polymer hydrophobicity.

  14. A Comparative Study on Micellar and Solubilizing Behavior of Three EO-PO Based Star Block Copolymers Varying in Hydrophobicity and Their Application for the In Vitro Release of Anticancer Drugs

    Directory of Open Access Journals (Sweden)

    Bijal Vyas

    2018-01-01

    Full Text Available The temperature and pH dependent self-assembly of three star shaped ethylene oxide-propylene oxide (EO-PO block copolymers (Tetronics® 304, 904 and 908 with widely different hydrophobicity was examined in aqueous solutions. Physico-chemical methods viz. viscosity, cloud point, solubilization along with thermal, scattering and spectral techniques shows strongly temperature and salt dependent solution behavior. T304 possessing low molecular weight did not form micelles; moderately hydrophilic T904 remained as micelles at ambient temperature and showed micellar growth while very hydrophilic T908 formed micelles at elevated temperatures. The surface activity/micellization/solubilization power was favored in the presence of salt. The copolymers turn more hydrophilic in acidic pH due to protonation of central ethylene diamine moiety that hinders micelle formation. The solubilization of a model insoluble azo dye 1-(o-Tolylazo-2-naphthol (Orange OT and hydrophobic drugs (quercetin and curcumin for copolymer solutions in aqueous and salt solutions are also reported. Among the three copolymers, T904 showed maximum solubility of dye and drugs, hence the in vitro release of drugs from T904 micelles was estimated and the effect on cytotoxicity of loading the drugs in T904 micelles was compared with the cytotoxicity of free drugs on the CHO-K1 cells. The results from the present work provide a better insight in selection of Tetronics® for their application in different therapeutic applications.

  15. Validation of methodologies for the analysis of lead and methyl-ether in gasoline, using the techniques of atomic emission with plasma source coupled inductively and micellar liquid chromatography

    International Nuclear Information System (INIS)

    Redondo Escalante, M.

    1995-01-01

    This study established and optimized the experimental variables for the lead quantization through the Icp-Aes technique, in aqueous media. A comparative study of several proposal methods, that appears in the literature for the extraction in aqueous media of the lead in gasoline was made. It determined that it is not possible, to make this procedure using the reaction of hydrolysis of tetraethyl lead. The op tim conditions were established, for the lead quantization in gasoline, using methyl-isobutyl-ketone and also ethanol as dis solvents. The conditions of the proposed methodologies were optimized, and the variables of analytical performance were defined. It was demonstrated, that it is possible to prepare lead dissolution patterns, in organic media, starting from inorganic salts of this metal. The techniques of chromatography of gases and of liquid chromatography of high pressure, in the analysis of methyl-ter butyl-ether (Mtbe), were compared. It demonstrated that it is possible, to quantize the Mtbe through the HPLC technique, and it found that the 'micellar' liquid chromatography. (author) [es

  16. Technical note - the incorporation of ash content into gas content

    Energy Technology Data Exchange (ETDEWEB)

    Creech, M.; Mahoney, M. [Powercoal Pty. Ltd., Budgewoi, NSW (Australia)

    1995-12-31

    For gas content analysis in recent years, it has been standard procedure to report results on a `dry ash free` (daf) basis, under the assumption that gas only adsorbs onto coaly material. In order to test the relationship between ash and gas content, samples of various rock types were taken from two drillholes in the Newcastle Coalfield. The results of this study confirmed the correlation between gas content and ash, providing an accurate means of relating gas contents for all carbonaceous rock types. 4 refs., 5 figs., 1 tab.

  17. List of Article Contents

    Directory of Open Access Journals (Sweden)

    Editorial Section

    2014-12-01

    Full Text Available CONTENTS OF ARTICLES Premixed combustion of coconut oil in a hele-shaw cell DOI: 10.14710/ijred.3.3.155-160 155-160 Hadi Saroso, I.N.G. Wardana, Rudy Soenoko, Nurkholis Hamidi   Analysing the potential of retrofitting ultra-low heat loss triple vacuum glazed windows to an existing UK solid wall dwelling DOI: 10.14710/ijred.3.3.161-174 161-174 Saim Memon   Study of Gasohol as Alternative Fuel for Gasoline Substitution: Characteristics and Performances DOI: 10.14710/ijred.3.3.175-183 175-183 Bardi Murachman, Dicky Pranantyo, Eddie Sandjaya Putra   Thermal effects investigation on electrical properties of silicon solar cells treated by laser irradiation DOI: 10.14710/ijred.3.3.184-187 184-187 Ali Pourakbar Saffar, Bahman Deldadeh Barani   Synthesis of Trimethylolpropane Esters of Calophyllum Methyl Esters : Effect of Temperatur and Molar Ratio DOI: 10.14710/ijred.3.3.188-192 188-192 Yeti Widyawati, Ani Suryani, Muhammad Romli, Sukardi Sukardi   Incorporating Root Crops under Agro-Forestry as the Newly Potential Source of Food, Feed and Renewable Energy DOI: 10.14710/ijred.3.3.193-206 193-206 Yudi Widodo, St. A. Rahayuningsih, Nasir Saleh, Sri Wahyuningsih   Solmap: Project In India's Solar Resource Assessment DOI: 10.14710/ijred.3.3.207-216 207-216 Indradip Mitra, Kaushal Chhatbar, Ashvini Kumar, Godugunur Giridhar, Ramdhan Vashistha, Richard Meyer, Marko Schwandt   Thermo-economic Optimization of Solar Assisted Heating and Cooling (SAHC System DOI: 10.14710/ijred.3.3.217-227 217-227 A. Ghafoor, A. Munir   Combustion characteristics of diesel engine using producer gas and blends of Jatropha methyl ester with diesel in mixed fuel mode DOI: 10.14710/ijred.3.3.228-235 228-235 Hifjur Raheman, Debasish Padhee    

  18. List of Content

    Directory of Open Access Journals (Sweden)

    Editor IJRED

    2014-05-01

    Full Text Available CONTENTS OF ARTICLES page Tin (II Chloride Catalyzed Esterification of High FFA Jatropha Oil: Experimental and Kinetics Study DOI: 10.14710/ijred.3.2.75-81 75-81 Ratna Dewi Kusumaningtyas, Prima Astuti Handayani, Rochmadi Rochmadi, Suryo Purwono, Arief Budiman   Utilization of Iles-Iles and Sorghum Starch for Bioethanol Production DOI: 10.14710/ijred.3.2.83-89 83-89 Kusmiyati Kusmiyati, Agus Sulistiyono   Premixed Combustion of Kapok (ceiba pentandra seed oil on Perforated Burner DOI: 10.14710/ijred.3.2.91-97 91-97 I.K.G. Wirawan, I.N.G. Wardana,        Rudy Soenoko, Slamet Wahyudi   Castor Seed from Melkasa Agricultural Research Centre, East Showa, Ethiopia and it’s biodiesel performance in Four Stroke Diesel Engine DOI: 10.14710/ijred.3. 3.2.99-105 99-105 Tesfahun Tegegne Akanawa, Haimanot Gebrehiwot Moges, Ramesh Babu, Daniel Bisrat   Economic feasibility of large scale PV water pumping applications utilizing real field data for a case study in Jordan DOI: 10.14710/ijred.3.2.107-117 107-117 Ibrahim Odeh   Development of Briquette from Coir Dust and Rice Husk Blend: An Alternative Energy Source DOI: 10.14710/ijred.3.2.119-123 119-123 Md. Hamidul Islam, Md. Mosharraf Hossain,Md. Abdul Momin   Performance, Emissions and Combustion Characteristics of a Single Cylinder Diesel Engine Fuelled with Blends of Jatropha Methyl Ester and Diesel DOI: 10.14710/ijred.3.2.125-131 125-131 Debasish Padhee, Hifjur Raheman   The characteristic changes of betung bamboo (Dendrocalamus asper pretreated by fungal pretreatment DOI: 10.14710/ijred.3.2.133-143 133-143 Widya Fatriasari, Wasrin Syafii, Nyoman J Wistara, Khaswar Syamsu, Bambang Prasetya   Influence of the Determination Methods of K and C Parameters on the Ability of Weibull Distribution to Suitably Estimate Wind Potential and Electric Energy DOI: 10.14710/ijred.3.2.145-154 145-154 Ruben M. Mouangue, Myrin Y. Kazet, Alexis Kuitche, Jean-Marie Ndjaka    

  19. Standards-based Content Resources: A Prerequisite for Content Integration and Content Interoperability

    Directory of Open Access Journals (Sweden)

    Christian Galinski

    2010-05-01

    Full Text Available Objective: to show how standards-based approaches for content standardization, content management, content related services and tools as well as the respective certification systems not only guarantee reliable content integration and content interoperability, but also are of particular benefit to people with special needs in eAccessibility/eInclusion. Method: document MoU/MG/05 N0221 ''Semantic Interoperability and the need for a coherent policy for a framework of distributed, possibly federated repositories for all kinds of content items on a world-wide scale''2, which was adopted in 2005, was a first step towards the formulation of global interoperability requirements for structured content. These requirements -based on advanced terminological principles- were taken up in EU-projects such as IN-SAFETY (INfrastructure and SAFETY and OASIS (Open architecture for Accessible Services Integration and Standardization. Results: Content integration and content interoperability are key concepts in connection with the emergence of state-of-the-art distributed and federated databases/repositories of structured content. Given the fact that linguistic content items are increasingly combined with or embedded in non-linguistic content items (and vice versa, a systemic and generic approach to data modelling and content management has become the order of the day. Fulfilling the requirements of capability for multilinguality and multimodality, based on open standards makes software and database design fit for eAccessibility/eInclusion from the outset. It also makes structured content capable for global content integration and content interoperability, because it enhances its potential for being re-used and re-purposed in totally different eApplications. Such content as well as the methods, tools and services applied can be subject to new kinds of certification schemes which also should be based on standards. Conclusions: Content must be totally reliable in some

  20. An intelligent content discovery technique for health portal content management.

    Science.gov (United States)

    De Silva, Daswin; Burstein, Frada

    2014-04-23

    Continuous content management of health information portals is a feature vital for its sustainability and widespread acceptance. Knowledge and experience of a domain expert is essential for content management in the health domain. The rate of generation of online health resources is exponential and thereby manual examination for relevance to a specific topic and audience is a formidable challenge for domain experts. Intelligent content discovery for effective content management is a less researched topic. An existing expert-endorsed content repository can provide the necessary leverage to automatically identify relevant resources and evaluate qualitative metrics. This paper reports on the design research towards an intelligent technique for automated content discovery and ranking for health information portals. The proposed technique aims to improve efficiency of the current mostly manual process of portal content management by utilising an existing expert-endorsed content repository as a supporting base and a benchmark to evaluate the suitability of new content A model for content management was established based on a field study of potential users. The proposed technique is integral to this content management model and executes in several phases (ie, query construction, content search, text analytics and fuzzy multi-criteria ranking). The construction of multi-dimensional search queries with input from Wordnet, the use of multi-word and single-word terms as representative semantics for text analytics and the use of fuzzy multi-criteria ranking for subjective evaluation of quality metrics are original contributions reported in this paper. The feasibility of the proposed technique was examined with experiments conducted on an actual health information portal, the BCKOnline portal. Both intermediary and final results generated by the technique are presented in the paper and these help to establish benefits of the technique and its contribution towards effective

  1. Content analysis in information flows

    Energy Technology Data Exchange (ETDEWEB)

    Grusho, Alexander A. [Institute of Informatics Problems of Federal Research Center “Computer Science and Control” of the Russian Academy of Sciences, Vavilova str., 44/2, Moscow (Russian Federation); Faculty of Computational Mathematics and Cybernetics, Moscow State University, Moscow (Russian Federation); Grusho, Nick A.; Timonina, Elena E. [Institute of Informatics Problems of Federal Research Center “Computer Science and Control” of the Russian Academy of Sciences, Vavilova str., 44/2, Moscow (Russian Federation)

    2016-06-08

    The paper deals with architecture of content recognition system. To analyze the problem the stochastic model of content recognition in information flows was built. We proved that under certain conditions it is possible to solve correctly a part of the problem with probability 1, viewing a finite section of the information flow. That means that good architecture consists of two steps. The first step determines correctly certain subsets of contents, while the second step may demand much more time for true decision.

  2. Webizing mobile augmented reality content

    Science.gov (United States)

    Ahn, Sangchul; Ko, Heedong; Yoo, Byounghyun

    2014-01-01

    This paper presents a content structure for building mobile augmented reality (AR) applications in HTML5 to achieve a clean separation of the mobile AR content and the application logic for scaling as on the Web. We propose that the content structure contains the physical world as well as virtual assets for mobile AR applications as document object model (DOM) elements and that their behaviour and user interactions are controlled through DOM events by representing objects and places with a uniform resource identifier. Our content structure enables mobile AR applications to be seamlessly developed as normal HTML documents under the current Web eco-system.

  3. From water-in-oil to oil-in-water emulsions to optimize the production of fatty acids using ionic liquids in micellar systems.

    Science.gov (United States)

    Santos, Luísa D F; Coutinho, João A P; Ventura, Sónia P M

    2015-01-01

    Biocatalysis is nowadays considered as one of the most important tools in green chemistry. The elimination of multiple steps involved in some of the most complex chemical synthesis, reducing the amounts of wastes and hazards, thus increasing the reaction yields and decreasing the intrinsic costs, are the major advantages of biocatalysis. This work aims at improving the enzymatic hydrolysis of olive oil to produce valuable fatty acids through emulsion systems formed by long alkyl chain ionic liquids (ILs). The optimization of the emulsion and the best conditions to maximize the production of fatty acids were investigated. The stability of the emulsion was characterized considering the effect of several parameters, namely, the IL and its concentration and different water/olive oil volumetric ratios. ILs from the imidazolium and phosphonium families were evaluated. The results suggest that the ILs effect on the hydrolysis performance varies with the water concentration and the emulsion system formed, that is, water-in-oil or oil-in-water emulsion. Although at low water concentrations, the presence of ILs does not present any advantages for the hydrolysis reaction, at high water contents (in oil-in-water emulsions), the imidazolium-based IL acts as an enhancer of the lipase catalytic capacity, super-activating 1.8 times the enzyme, and consequently promoting the complete hydrolysis of the olive oil for the highest water contents [85% (v/v)]. © 2015 American Institute of Chemical Engineers.

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

    Science.gov (United States)

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

    2017-11-30

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

  5. Understanding Content-and-Structure

    NARCIS (Netherlands)

    Kamps, J.; Marx, M.J.; de Rijke, M.; Sigurbjörnsson, B.; Trotman, A.; Lalmas, M.; Fuhr, N.

    2005-01-01

    Document-centric XML is a mixture of text and structure. +With the increased availability of document-centric XML content comes a need for query facilities in which both structural constraints and constraints on the content of the documents can be expressed. This has generated considerable interest

  6. Uranium content of Philippine coals

    International Nuclear Information System (INIS)

    De la Rosa, A.M.; Sombrito, E.Z.; Nuguid, Z.S.; Bulos, A.M.; Bucoy, B.M.; De la Cruz, M.

    1984-01-01

    Uranium content of coal samples from seven areas in the Philippines, i.e. Cebu, Semirara, Bislig, Albay, Samar, Malangas and Polilio Is. was found to contain trace quantities of uranium. The mean value of 0.401 ppm U is lower than reported mean uranium contents for coal from other countries. (ELC)

  7. Evolution of broadcast content distribution

    CERN Document Server

    Beutler, Roland

    2017-01-01

    This book discusses opportunities for broadcasters that arise with the advent of broadband networks, both fixed and mobile. It discusses how the traditional way of distributing audio-visual content over broadcasting networks has been complemented by the usage of broadband networks. The author shows how this also gives the possibility to offer new types of interactive or so-called nonlinear services. The book illustrates how change in distribution technology is accelerating the need for broadcasters around the world to adapt their content distribution strategy and how it will impact the portfolios of content they offer. Outlines the shift in broadcast content distribution paradigms and related strategic issues Provides an overview of the new broadcasting ecosystem encompassing new types of content, user habits, expectations, and devices Discusses complementary usage of different distribution technologies and platforms.

  8. Moisture content measurement in paddy

    Science.gov (United States)

    Klomklao, P.; Kuntinugunetanon, S.; Wongkokua, W.

    2017-09-01

    Moisture content is an important quantity for agriculture product, especially in paddy. In principle, the moisture content can be measured by a gravimetric method which is a direct method. However, the gravimetric method is time-consuming. There are indirect methods such as resistance and capacitance methods. In this work, we developed an indirect method based on a 555 integrated circuit timer. The moisture content sensor was capacitive parallel plates using the dielectric constant property of the moisture. The instrument generated the output frequency that depended on the capacitance of the sensor. We fitted a linear relation between periods and moisture contents. The measurement results have a standard uncertainty of 1.23 % of the moisture content in the range of 14 % to 20 %.

  9. Content-based intermedia synchronization

    Science.gov (United States)

    Oh, Dong-Young; Sampath-Kumar, Srihari; Rangan, P. Venkat

    1995-03-01

    Inter-media synchronization methods developed until now have been based on syntactic timestamping of video frames and audio samples. These methods are not fully appropriate for the synchronization of multimedia objects which may have to be accessed individually by their contents, e.g. content-base data retrieval. We propose a content-based multimedia synchronization scheme in which a media stream is viewed as hierarchial composition of smaller objects which are logically structured based on the contents, and the synchronization is achieved by deriving temporal relations among logical units of media object. content-based synchronization offers several advantages such as, elimination of the need for time stamping, freedom from limitations of jitter, synchronization of independently captured media objects in video editing, and compensation for inherent asynchronies in capture times of video and audio.

  10. Determinação do 5-hidroximetilfurfural em méis utilizando cromatografia eletrocinética capilar micelar Determination of 5-hydroxymethyl-2-furaldehyde in honey by micellar eletrokinetic capillary electrophoresis

    Directory of Open Access Journals (Sweden)

    Sandra Jussara Nunes da Silva

    2008-12-01

    Full Text Available Neste trabalho foi investigado o índice de HMF (5-hidroximetilfurfural em méis comercializados em Porto Alegre - RS, utilizando Cromatografia Capilar Eletrocinética Micelar. O HMF, produto da condensação da frutose, é um indicador da qualidade e conservação do mel. Foram analisadas 11 marcas de méis comercializados na cidade de Porto Alegre. O composto estudado esteve presente em todas as amostras, em um intervalo de concentração de 0,191 a 6,206 mg.kg-1. Para quantificar o HMF presente nos méis, utilizou-se a técnica de adição de padrão. A taxa de recuperação foi de 98% e o limite de detecção foi de 0,025 mg.kg-1. O limite permitido de HMF em méis, segundo a legislação brasileira, é de 60 mg.kg-1.In this work, the occurrence of HMF (5-hydroxymethylfurfural in honey marketed in Porto Alegre - RS was investigated using Micellar Electrokinetic Capillary Chromatography. The HMF, which is the product of the fructose condensation, is an indicator of honey quality and conservation. Eleven types of honey commercialized in Porto Alegre were analyzed, and all of them contained HMF in a range from 0.191 to 6.206 mg.kg-1. In order to quantify the HMF present in the samples, the technique of standard addition was employed. The recovery was 98% and the detection limit was 0.025 mg.kg-1. The allowed limit of HMF in honey, according to the Brazilian Legislation, is 60 mg.kg-1.

  11. Trace analysis of three antihistamines in human urine by on-line single drop liquid-liquid-liquid microextraction coupled to sweeping micellar electrokinetic chromatography and its application to pharmacokinetic study.

    Science.gov (United States)

    Gao, Wenhua; Chen, Yunsheng; Chen, Gaopan; Xi, Jing; Chen, Yaowen; Yang, Jianying; Xu, Ning

    2012-09-01

    A rapid and efficient dual preconcentration method of on-line single drop liquid-liquid-liquid microextraction (SD-LLLME) coupled to sweeping micellar electrokinetic chromatography (MEKC) was developed for trace analysis of three antihistamines (mizolastine, chlorpheniramine and pheniramine) in human urine. Three analytes were firstly extracted from donor phase (4 mL urine sample) adjusted to alkaline condition (0.5 M NaOH). The unionized analytes were subsequently extracted into a drop of n-octanol layered over the urine sample, and then into a microdrop of acceptor phase (100 mM H(3)PO(4)) suspended from a capillary inlet. The enriched acceptor phase was on-line injected into capillary with a height difference and then analyzed directly by sweeping MEKC. Good linear relationships were obtained for all analytes in a range of 6.25 × 10(-6) to 2.5 × 10(-4)g/L with correlation coefficients (r) higher than 0.987. The proposed method achieved limits of detections (LOD) varied from 1.2 × 10(-7) to 9.5 × 10(-7)g/L based on a signal-to-noise of 3 (S/N=3) with 751- to 1372-fold increases in detection sensitivity for analytes, and it was successfully applied to the pharmacokinetic study of three antihistamines in human urine after an oral administration. The results demonstrated that this method was a promising combination for the rapid trace analysis of antihistamines in human urine with the advantages of operation simplicity, high enrichment factor and little solvent consumption. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Catalysis in the Service of Green Chemistry: Nobel Prize-Winning Palladium-Catalysed Cross-Couplings, Run in Water at Room Temperature: Heck, Suzuki-Miyaura and Negishi reactions carried out in the absence of organic solvents, enabled by micellar catalysis.

    Science.gov (United States)

    Lipshutz, Bruce H; Taft, Benjamin R; Abela, Alexander R; Ghorai, Subir; Krasovskiy, Arkady; Duplais, Christophe

    2012-04-01

    Palladium-catalysed cross-couplings, in particular Heck, Suzuki-Miyaura and Negishi reactions developed over three decades ago, are routinely carried out in organic solvents. However, alternative media are currently of considerable interest given an increasing emphasis on making organic processes 'greener'; for example, by minimising organic waste in the form of organic solvents. Water is the obvious leading candidate in this regard. Hence, this review focuses on the application of micellar catalysis, in which a 'designer' surfactant enables these award-winning coupling reactions to be run in water at room temperature.

  13. Visual Analysis of Weblog Content

    Energy Technology Data Exchange (ETDEWEB)

    Gregory, Michelle L.; Payne, Deborah A.; McColgin, Dave; Cramer, Nick O.; Love, Douglas V.

    2007-03-26

    In recent years, one of the advances of the World Wide Web is social media and one of the fastest growing aspects of social media is the blogosphere. Blogs make content creation easy and are highly accessible through web pages and syndication. With their growing influence, a need has arisen to be able to monitor the opinions and insight revealed within their content. In this paper we describe a technical approach for analyzing the content of blog data using a visual analytic tool, IN-SPIRE, developed by Pacific Northwest National Laboratory. We highlight the capabilities of this tool that are particularly useful for information gathering from blog data.

  14. Web content a writer's guide

    CERN Document Server

    Mizrahi, Janet

    2013-01-01

    The explosion of electronic sources, whether in the form of news, commentary, sales and marketing, or information, has created boundless opportunities for producing content. Whether you're an entrepreneur with a start-up business who needs a website, an executive who uses social media to connect with various stakeholders, or a content provider blogging about topical issues, you'll need to know how to write for the web and address the unique environment of the digital world. This book will help you produce web content that generates results. Writing for the screen differs from writing for a pri

  15. [Exploring dream contents by neuroimaging].

    Science.gov (United States)

    Horikawa, Tomoyasu; Kamitani, Yukiyasu

    2014-04-01

    Dreaming is a subjective experience during sleep that is often accompanied by vivid perceptual and emotional contents. Because of its fundamentally subjective nature, the objective study of dream contents has been challenging. However, since the discovery of rapid eye movements during sleep, scientific knowledge on the relationship between dreaming and physiological measures including brain activity has accumulated. Recent advances in neuroimaging analysis methods have made it possible to uncover direct links between specific dream contents and brain activity patterns. In this review, we first give a historical overview on dream researches with a focus on the neurophysiological and behavioral signatures of dreaming. We then discuss our recent study in which visual dream contents were predicted, or decoded, from brain activity during sleep onset periods using machine learning-based pattern recognition of functional MRI data. We suggest that advanced analytical tools combined with neural and behavioral databases will reveal the relevance of spontaneous brain activity during sleep to waking experiences.

  16. Satellite Ocean Heat Content Suite

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This collection contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and Information...

  17. Data content standards in Africa

    CSIR Research Space (South Africa)

    Cooper, Antony K

    2005-04-01

    Full Text Available Data content standards tend to be more accessible. Easier to understand. Used directly by many end users. Immediately applicable to Africa. More susceptible to culture and language – Hence, more important to have local standards...

  18. Concrete workability and fibre content

    OpenAIRE

    Vikan, Hedda

    2007-01-01

    Research report Parameters influencing the workability of fibre concrete and maximum fibre content are given in this state of the art report along with the range of fibre types available on today’s market. The study reveales that new placing techniques and production methods are crucial in order to increase fibre content and concrete strength. Achieving the same mechanical properties as traditionally reinforced concrete will probably also demand changes of the matrix. Finally, reco...

  19. Marketing engagement through visual content

    Directory of Open Access Journals (Sweden)

    Marius MANIC

    2015-12-01

    Full Text Available Engaging visual is a must in the modern marketing world. Wide access to mass communication devices, with extended visuals enhancements, made visual content an important point of interest for any publisher, on all media channels. The decreasing costs and huge variety of types are premises for an easy and effective marketing investment, with strong benefits for any company and its brands. Loyal customers are achieved and kept through visual content; the lack of it in the general marketing

  20. Fluorine content of Fukien teas

    Energy Technology Data Exchange (ETDEWEB)

    Wang, T H; Lin, C S; Wu, C; Liao, C E; Lin, H Y

    1949-01-01

    A study was made on the fluorine contents of Fukien teas and analytical results indicated the amount ranged from 5.7 to 35.5 mg. per 100 grams of dry tea. The high content of fluorine was found not to be due to contamination nor to the high fluorine content of the soil in which the tea plant was cultivated. Differences in the methods of manufacture had no effect on the fluorine content of the final products. Different varieties of tea plants have different powers to absorb fluorine from the soil. Of the two varieties of tea plants studied, Shui-Sen leaves possessed the lower fluorine content. Age of the tea leaves exerted an important influence on the fluorine content, the older leaves containing considerably more fluorine than the younger. The amount of fluorine that may be extracted in a two per cent infusion varies from 29.1 per cent for fresh leaves to 50.5 per cent for black tea. The process of roasting and rolling rendered the fluorine more soluble, hence the amount extracted increased in green tea. Fermentation further increased the extractability of the fluorine; thus the amount extracted was the highest in black tea, which was fermented, less in the semi-fermented oolong tea, and least in the unfermented green tea. The extractability of fluorine was also increased with age of the leaves.

  1. 23Na and 35/37Cl as NMR probes of growth and shape of sodium taurodeoxycholate micellar aggregates in the presence of NaCl.

    Science.gov (United States)

    Asaro, Fioretta; Feruglio, Luigi; Galantini, Luciano; Nardelli, Alessia

    2013-02-15

    The growth of the aggregates of the dihydroxylated bile salt sodium taurodeoxycholate (NaTDC) upon NaCl addition and the involvement of the counterion were investigated by NMR spectroscopy of monoatomic ionic species. (23)Na T(1) values from 0.015, 0.100, and 0.200 mol kg(-1) NaTDC solutions in D(2)O, at variable NaCl content, proved to be sensitive to the transition from primary to secondary aggregates, which occurs in the former sample, and to intermicellar interaction. Some (79)Br NMR measurements were performed on a 0.100 mol kg(-1) NaTDC sample added by NaBr in place of NaCl for comparison purposes. The (23)Na, (35)Cl, and (37)Cl double quantum filtered (DQF) patterns, from the 0.100 mol kg(-1) NaTDC sample, and (23)Na ones also from the 0.200 mol kg(-1) NaTDC one, in the presence of 0.750 mol kg(-1) NaCl, are a clear manifestation of motional anisotropy. Moreover, the DQF spectra of (23)Na and (37)Cl, which possess close quadrupole moments, display a striking similarity. The DQF lineshapes were simulated exploiting the Scilab environment to obtain an estimate of the residual quadrupole splitting magnitude. These results support the description of NaTDC micelles as cylindrical aggregates, strongly interacting at high ionic strengths, and capable of association with added electrolytes. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. Contents

    OpenAIRE

    BAHAR, Mehmet; KİLMEN, Sevilay; Editörleri, Dil; Türkçe, Salih Kürşad DOLUNAY; İngilizce, Selmin SÖYLEMEZ; YAVUZALP, Nuh; ALPAGUT, Uğur; ALTUN, Murat; AYDOĞAN, Yasemin; AVCI, Cemal; DURMUŞ, Soner; KALYONCU, Nesrin; ORBAY, Metin; ÖZBAY, Murat; TAŞPINAR, Mehmet

    2015-01-01

    Yayın Kurulu: Prof.Dr. Uğur ALPAGUT Prof.Dr. Murat ALTUN Prof.Dr. Yasemin AYDOĞAN Prof.Dr. Cemal AVCI Prof.Dr. Soner DURMUŞ Prof.Dr. Nesrin KALYONCU Prof.Dr. Metin ORBAY Prof.Dr. Murat ÖZBAY Prof.Dr. Mehmet TAŞPINAR Doç.Dr. Türkan ARGON Doç.Dr. Zeki ARSAL Doç.Dr. Bayram BIÇAK Doç.Dr. Bahri AYDIN Doç.Dr. Mehmet CANBULAT Doç.Dr. Eyüp COŞKUN Doç.Dr. Nihal DOĞAN Doç.Dr. Tolga ERDOĞAN Doç.Dr. Halit KARATAY Doç.Dr. Kemalettin KUZUCU Doç.Dr. Salih Paşa MEMİŞOĞLU Doç.Dr. Şenay Se...

  3. Pre-service teachers' content knowledge and pedagogical content ...

    African Journals Online (AJOL)

    This study investigated pre-service teachers' content and pedagogical knowledge in teaching geometric transformation. Eighty-two pre-service teachers from two Colleges of Education in the Ashanti region of Ghana consisted the sample size. The study was a quantitative study which employed survey as a strategy of ...

  4. Hybrid Model of Content Extraction

    DEFF Research Database (Denmark)

    Qureshi, Pir Abdul Rasool; Memon, Nasrullah

    2012-01-01

    We present a hybrid model for content extraction from HTML documents. The model operates on Document Object Model (DOM) tree of the corresponding HTML document. It evaluates each tree node and associated statistical features like link density and text distribution across the node to predict...... significance of the node towards overall content provided by the document. Once significance of the nodes is determined, the formatting characteristics like fonts, styles and the position of the nodes are evaluated to identify the nodes with similar formatting as compared to the significant nodes. The proposed...

  5. The Natural Origins of Content

    DEFF Research Database (Denmark)

    Hutto, Daniel; Satne, Glenda Lucila

    2015-01-01

    to be reconceived in terms of explaining the natural origins of content. Second, the pivotal assumption that intentionality is always and everywhere contentful must be abandoned. Reviving and updating Haugeland’s baseball analogy in the light of these changes, we propose ways of redirecting the efforts of players...... on each base of his intentionality All-Star team, enabling them to start functioning effectively as a team. Only then is it likely that they will finally get their innings and maybe, just maybe, even win the game....

  6. Investigation of anti-Hepatitis C virus, sofosbuvir and daclatasvir, in pure form, human plasma and human urine using micellar monolithic HPLC-UV method and application to pharmacokinetic study.

    Science.gov (United States)

    Zidan, Dalia W; Hassan, Wafaa S; Elmasry, Manal S; Shalaby, Abdalla A

    2018-06-01

    Simultaneous determination of sofosbuvir (SOF), and daclatasvir (DAC) in their dosage forms, human urine and human plasma using simple and rapid micellar high performance liquid chromatographic method coupled with UV detection (HPLC-UV) had been developed and validated. These drugs are described as co-administered for treatment of Hepatitis C virus (HCV). HCV is the cause of Hepatitis C and some cancers such as liver cancer (hepatocellular carcinoma) and lymphomas in humans. Separation and quantitation were carried out on anonyx™ C 8 monolithic (100 × 4.6 mm (i.d.) analytical column maintained at 25 °C. The mobile phase consisted of 0.1 M sodium dodecyl sulfate (SDS) solution containing 20% (V/V) n-propanolol and 0.3% (V/V) triethylamine and pH was adjusted to 6.5 using 0.02 M phosphoric acid, respectively. The retention times of SOF and DAC were 4.8 min, and 6.5 min, respectively. Measurements were made at flow rate of 0.5 mL/min with injection volume of 20 μL and ultraviolet (UV) detection at 226 nm. Linearity of SOF and DAC was obtained over concentration ranges of 50-400, and 40-400 ng/mL, respectively in pure form, 60-300 and 50-300 ng/mL, respectively for human plasma and over 50-400, and 40-400 ng/mL, respectively for human urine with correlation coefficient >0.999. The proposed method demonstrated excellent intra- and inter-day precision and accuracy. The suggested method was applied for determination of the drugs in pure, dosage form, and in real human plasma, real human urine and drug-dissolution test of their tablets. The obtained results have been statistically compared to reported method to give a conclusion that there is no significant differences. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Journalism and Explaining News Content

    NARCIS (Netherlands)

    Albæk, E.; Skovsgaard, M.; de Vreese, C.H.; Nussbaum, J.F.

    Three models are presented to explain variation in news content. In the first model the explanation is based on the individual journalist, in the second model on the professional journalist, and in the third model on the organized journalist. The individual journalist model focuses on how the

  8. Quality Content in Distance Education

    Science.gov (United States)

    Yildiz, Ezgi Pelin; Isman, Aytekin

    2016-01-01

    In parallel with technological advances in today's world of education activities can be conducted without the constraints of time and space. One of the most important of these activities is distance education. The success of the distance education is possible with content quality. The proliferation of e-learning environment has brought a need for…

  9. Content dependent information flow control

    DEFF Research Database (Denmark)

    Nielson, Hanne Riis; Nielson, Flemming

    2017-01-01

    Information flow control extends access control by not only regulating who is allowed to access what data but also the subsequent use of the data. Applications within communications systems require such information flow control to be dependent on the actual contents of the data. We develop...

  10. Open Content in Open Context

    Science.gov (United States)

    Kansa, Sarah Whitcher; Kansa, Eric C.

    2007-01-01

    This article presents the challenges and rewards of sharing research content through a discussion of Open Context, a new open access data publication system for field sciences and museum collections. Open Context is the first data repository of its kind, allowing self-publication of research data, community commentary through tagging, and clear…

  11. Home media server content management

    Science.gov (United States)

    Tokmakoff, Andrew A.; van Vliet, Harry

    2001-07-01

    With the advent of set-top boxes, the convergence of TV (broadcasting) and PC (Internet) is set to enter the home environment. Currently, a great deal of activity is occurring in developing standards (TV-Anytime Forum) and devices (TiVo) for local storage on Home Media Servers (HMS). These devices lie at the heart of convergence of the triad: communications/networks - content/media - computing/software. Besides massive storage capacity and being a communications 'gateway', the home media server is characterised by the ability to handle metadata and software that provides an easy to use on-screen interface and intelligent search/content handling facilities. In this paper, we describe a research prototype HMS that is being developed within the GigaCE project at the Telematica Instituut . Our prototype demonstrates advanced search and retrieval (video browsing), adaptive user profiling and an innovative 3D component of the Electronic Program Guide (EPG) which represents online presence. We discuss the use of MPEG-7 for representing metadata, the use of MPEG-21 working draft standards for content identification, description and rights expression, and the use of HMS peer-to-peer content distribution approaches. Finally, we outline explorative user behaviour experiments that aim to investigate the effectiveness of the prototype HMS during development.

  12. Digital Content: Making Learning Relevant

    Science.gov (United States)

    Levin, Douglas A.

    2011-01-01

    Approximately 15 states are changing their policies to give school districts more flexibility in acquiring content. They have changed laws or policies or have bills pending in state legislatures to redefine "textbooks". Most of those changes are similar to the approach Indiana took in its new law: a "textbook" is not only a…

  13. Place prioritization for biodiversity content

    Indian Academy of Sciences (India)

    The prioritization of places on the basis of biodiversity content is part of any systematic biodiversity conservation planning process. The place prioritization procedure implemented in the ResNet software package is described. This procedure is primarily based on the principles of rarity and complementarity. Application of the ...

  14. Variation in seasonal moisture content

    Science.gov (United States)

    John E. Phelps

    1992-01-01

    Several properties of wood are affected by moisture content-weight, fuel value, electrical conductivity, strength, and shrinkage. Differences in these properties are commonly observed in wood in service. For example, a green 2 X 4 weighs more than a kiln-dried 2 X 4, dried wood burns more easily and hotter than green wood, etc.

  15. Content, Context & Connectivity Persuasive Interplay

    DEFF Research Database (Denmark)

    Sørensen, Christian Grund

    2013-01-01

    -supported research project under EACEA). In the development of this project several categories of content have been implemented in technology enhanced learning tools. These have been designed to support learning in different contexts and eventually the role of the connectivity of these learning objects and tools......The aim of this paper is to discuss the relationship between content, context and connectivity and suggesting a model of Dynamic Interplay. This is done in relation to a specific learning environment concerning cultural mediation, in casu the Kaj Munk Case of the EuroPLOT-project (an EU...... is discussed. Focus is here on The Kaj Munk Study Edition, The Conceptual Pond, Immersive Layers Design, and Generative Learning Objects (GLOs) which are applications affiliated with the Munk case. This paper explores the persuasive potential of the interplay between the different applications for the benefit...

  16. The information content of options

    OpenAIRE

    Navon, Yonatan

    2017-01-01

    The objective of this thesis is to examine the information content of stock options in financial markets. A key question in financial economics is how information diffuses across markets and how quickly it is reflected in security prices. This thesis aims at exploring this question by investigating the informational role that options play in financial markets. This is achieved by exploring the joint cross section of option and bond prices, the informational role of options in seasoned equity ...

  17. Water content of aged aerosol

    OpenAIRE

    G. J. Engelhart; L. Hildebrandt; E. Kostenidou; N. Mihalopoulos; N. M. Donahue; S. N. Pandis

    2010-01-01

    The composition and physical properties of aged atmospheric aerosol were characterized at a remote sampling site on the northern coast of Crete, Greece during the Finokalia Aerosol Measurement Experiment in May 2008 (FAME-2008). A reduced Dry-Ambient Aerosol Size Spectrometer (DAASS) was deployed to measure the aerosol water content and volumetric growth factor of fine particulate matter. The particles remained wet even at relative humidity (RH) as low as 20%. The aerosol was acidic during mo...

  18. Content, Cost, Chance, and Collection

    OpenAIRE

    Lorenzen, Mark

    2007-01-01

    This Working Paper argues that the film industry is a paradigmatic example of how the organization of the cultural economy is shaped by balancing creativity with contextual issues. In the film industry, organization is far from determined only by creative concerns for content production: Issues of cost, chance and collection also play important roles. Through analyzing creativity and its context in the film industry, the paper explains the industry’s organization, and opens up for understandi...

  19. Detecting Malicious Content on Facebook

    OpenAIRE

    Dewan, Prateek; Kumaraguru, Ponnurangam

    2015-01-01

    Online Social Networks (OSNs) witness a rise in user activity whenever an event takes place. Malicious entities exploit this spur in user-engagement levels to spread malicious content that compromises system reputation and degrades user experience. It also generates revenue from advertisements, clicks, etc. for the malicious entities. Facebook, the world's biggest social network, is no exception and has recently been reported to face much abuse through scams and other type of malicious conten...

  20. Plutonium content in uranium minerals

    International Nuclear Information System (INIS)

    Garzon Ruiperez, L.

    1975-01-01

    Starting from a ore model constituted by a uniformily dispersed UO 2 into a granite matrix, the Pu/U ratio as a function of UO 2 concentration in the ore have been deduced. The calculated values are roughly one or two orders of magnitude less than the experimental ones carried out in several types of ores. However, taking into account the H content in the matrix (as a water component) the obtained values agree satisfactorili with the experimental ones. (author) [es

  1. Material obligations: Forms and content

    International Nuclear Information System (INIS)

    Johnson, L.

    1998-01-01

    This paper includes a detailed legal framework of the IAEA safeguards agreements, namely basic articles of the IAEA Statute, Treaty and Supply Agreement obligations and basic documents concerning decisions and practices of the Board of Governors. It describes as well the initiation process of the negotiation of safeguards agreements, contents comparison and implementation of the safeguards agreements, protocols to safeguards agreements, subsidiary arrangements, amendments and renegotiation documents

  2. Content metamorphosis in synthetic holography

    International Nuclear Information System (INIS)

    Desbiens, Jacques

    2013-01-01

    A synthetic hologram is an optical system made of hundreds of images amalgamated in a structure of holographic cells. Each of these images represents a point of view on a three-dimensional space which makes us consider synthetic holography as a multiple points of view perspective system. In the composition of a computer graphics scene for a synthetic hologram, the field of view of the holographic image can be divided into several viewing zones. We can attribute these divisions to any object or image feature independently and operate different transformations on image content. In computer generated holography, we tend to consider content variations as a continuous animation much like a short movie. However, by composing sequential variations of image features in relation with spatial divisions, we can build new narrative forms distinct from linear cinematographic narration. When observers move freely and change their viewing positions, they travel from one field of view division to another. In synthetic holography, metamorphoses of image content are within the observer's path. In all imaging Medias, the transformation of image features in synchronisation with the observer's position is a rare occurrence. However, this is a predominant characteristic of synthetic holography. This paper describes some of my experimental works in the development of metamorphic holographic images.

  3. Water content of aged aerosol

    Directory of Open Access Journals (Sweden)

    G. J. Engelhart

    2011-02-01

    Full Text Available The composition and physical properties of aged atmospheric aerosol were characterized at a remote sampling site on the northern coast of Crete, Greece during the Finokalia Aerosol Measurement Experiment in May 2008 (FAME-2008. A reduced Dry-Ambient Aerosol Size Spectrometer (DAASS was deployed to measure the aerosol water content and volumetric growth factor of fine particulate matter. The particles remained wet even at relative humidity (RH as low as 20%. The aerosol was acidic during most of the measurement campaign, which likely contributed to the water uptake at low RH. The water content observations were compared to the thermodynamic model E-AIM, neglecting any contribution of the organics to aerosol water content. There was good agreement between the water measurements and the model predictions. Adding the small amount of water associated with the organic aerosol based on monoterpene water absorption did not change the quality of the agreement. These results strongly suggest that the water uptake by aged organic aerosol is relatively small (a few percent of the total water for the conditions during FAME-08 and generally consistent with what has been observed in laboratory experiments. The water concentration measured by a Q-AMS was well correlated with the DAASS measurements and in good agreement with the predicted values for the RH of the Q-AMS inlet. This suggests that, at least for the conditions of the study, the Q-AMS can provide valuable information about the aerosol water concentrations if the sample is not dried.

  4. Content Based Searching for INIS

    International Nuclear Information System (INIS)

    Jain, V.; Jain, R.K.

    2016-01-01

    Full text: Whatever a user wants is available on the internet, but to retrieve the information efficiently, a multilingual and most-relevant document search engine is a must. Most current search engines are word based or pattern based. They do not consider the meaning of the query posed to them; purely based on the keywords of the query; no support of multilingual query and and dismissal of nonrelevant results. Current information-retrieval techniques either rely on an encoding process, using a certain perspective or classification scheme, to describe a given item, or perform a full-text analysis, searching for user-specified words. Neither case guarantees content matching because an encoded description might reflect only part of the content and the mere occurrence of a word does not necessarily reflect the document’s content. For general documents, there doesn’t yet seem to be a much better option than lazy full-text analysis, by manually going through those endless results pages. In contrast to this, new search engine should extract the meaning of the query and then perform the search based on this extracted meaning. New search engine should also employ Interlingua based machine translation technology to present information in the language of choice of the user. (author

  5. Facilitating personal content management in smart phones

    NARCIS (Netherlands)

    Aaltonen, Antti

    2007-01-01

    Smart phones, which combine, e.g., communication and mobile multimedia features, store increasing amount of media content and so they face content management challenges similar to what desktop computers are experiencing. Content management refers to actions performed on content (e.g., capture image,

  6. Heavy Sexual Content Versus Safer Sex Content: A Content Analysis of the Entertainment Education Drama Shuga.

    Science.gov (United States)

    Booker, Nancy Achieng'; Miller, Ann Neville; Ngure, Peter

    2016-12-01

    Extremely popular with Kenyan youth, the entertainment-education drama Shuga was designed with specific goals of promoting condom use, single versus multiple sexual partners, and destigmatization of HIV. Almost as soon as it aired, however, it generated controversy due to its extensive sexual themes and relatively explicit portrayal of sexual issues. To determine how safer sex, antistigma messages, and overall sexual content were integrated into Shuga, we conducted a content analysis. Results indicated that condom use and HIV destigmatization messages were frequently and clearly communicated. Negative consequences for risky sexual behavior were communicated over the course of the entire series. Messages about multiple concurrent partnerships were not evident. In addition, in terms of scenes per hour of programming, Shuga had 10.3 times the amount of sexual content overall, 8.2 times the amount of sexual talk, 17.8 times the amount of sexual behavior, and 9.4 times the amount of sexual intercourse as found in previous analysis of U.S. entertainment programming. Research is needed to determine how these factors may interact to influence adolescent viewers of entertainment education dramas.

  7. Caffeine content of decaffeinated coffee.

    Science.gov (United States)

    McCusker, Rachel R; Fuehrlein, Brian; Goldberger, Bruce A; Gold, Mark S; Cone, Edward J

    2006-10-01

    Caffeine is the most widely consumed drug in the world with coffee representing a major source of intake. Despite widespread availability, various medical conditions necessitate caffeine-restricted diets. Patients on certain prescription medications are advised to discontinue caffeine intake. Such admonition has implications for certain psychiatric patients because of pharmacokinetic interactions between caffeine and certain anti-anxiety drugs. In an effort to abstain from caffeine, patients may substitute decaffeinated for caffeinated coffee. However, decaffeinated beverages are known to contain caffeine in varying amounts. The present study determined the caffeine content in a variety of decaffeinated coffee drinks. In phase 1 of the study, 10 decaffeinated samples were collected from different coffee establishments. In phase 2 of the study, Starbucks espresso decaffeinated (N=6) and Starbucks brewed decaffeinated coffee (N=6) samples were collected from the same outlet to evaluate variability of caffeine content of the same drink. The 10 decaffeinated coffee samples from different outlets contained caffeine in the range of 0-13.9 mg/16-oz serving. The caffeine content for the Starbucks espresso and the Starbucks brewed samples collected from the same outlet were 3.0-15.8 mg/shot and 12.0-13.4 mg/16-oz serving, respectively. Patients vulnerable to caffeine effects should be advised that caffeine may be present in coffees purported to be decaffeinated. Further research is warranted on the potential deleterious effects of consumption of "decaffeinated" coffee that contains caffeine on caffeine-restricted patients. Additionally, further exploration is merited for the possible physical dependence potential of low doses of caffeine such as those concentrations found in decaffeinated coffee.

  8. Micellar and antibody-targeted polymer therapeutics

    Czech Academy of Sciences Publication Activity Database

    Etrych, Tomáš; Chytil, Petr; Kovář, Lubomír; Říhová, Blanka; Ulbrich, Karel

    2010-01-01

    Roč. 295, - (2010), s. 1-12 ISSN 1022-1360. [Prague Meetings on Macromolecules /73./ New Frontiers in Macromolecular Science: From Macromolecular Concepts of Living Matter to Polymers for Better Quality of Life. Prague, 05.07.2009-09.07.2009] R&D Projects: GA AV ČR IAA400500806; GA AV ČR IAAX00500803; GA MŠk 1M0505 Institutional research plan: CEZ:AV0Z40500505; CEZ:AV0Z50200510 Keywords : doxorubicin * drug delivery systems * HPMA copolymers Subject RIV: CD - Macromolecular Chemistry

  9. Micellar nanomedicine of human neuropeptide Y.

    Science.gov (United States)

    Kuzmis, Antonina; Lim, Sok Bee; Desai, Esha; Jeon, Eunjung; Lee, Bao-Shiang; Rubinstein, Israel; Onyüksel, Hayat

    2011-08-01

    Human neuropeptide Y (NPY) is an important biologics that regulates a multitude of physiological functions and could be amenable to therapeutic manipulations in certain disease states. However, rapid (within minutes) enzymatic degradation and inactivation of NPY precludes its development as a drug. Accordingly, we determined whether self-association of NPY with biocompatible and biodegradable sterically stabilized phospholipid micelles (SSM) improves its stability and bioactivity. We found that in saline NPY spontaneously aggregates; however, in the presence of SSM it self-associates with the micelles as monomers. Three NPY molecules self-associate with 1 SSM at saturation. This process stabilizes the peptide in α-helix conformation, abrogates its degradation by dipeptidyl peptidase-4 and potentiates NPY-induced inhibition of cAMP elaboration in SK-N-MC cells. Collectively, these data indicate that self-association of NPY with SSM stabilizes and protects the peptide in active monomeric conformation, thereby amplifying its bioactivity in vitro. We propose further development of NPY in SSM as a novel, long-acting nanomedicine. Human neuropeptide Y (NPY) regulates a multitude of physiological functions and could be amenable to therapeutic manipulations, which is currently limited by its short half life. Self-association of NPY with spherically stabilized micelles (SSM) protects and stabilizes the peptide in active monomeric conformation, thereby amplifying its bioactivity in vitro, enabling future therapeutic considerations. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. oxidation of acetaldehyde in aqueous micellar

    Indian Academy of Sciences (India)

    Susanta Malik

    Different spectroscopic methods have been applied to investigate the chromic acid oxidation of acetaldehyde in ... industrial engineering and chemistry. Acetaldehyde is ... chemical world as a solvent, as a precursor for organic synthesis, in the ...

  11. Measuring ash content of coal

    International Nuclear Information System (INIS)

    Clayton, C.G.; Wormald, M.R.

    1980-01-01

    An apparatus for measuring the ash content of coal is claimed. It comprises a means for irradiating a known quantity of coal in a transport container with a known dose of neutrons, a means for detecting γ-rays having a predetermined energy emitted by the irradiated coal, the γ-rays being indicative of the presence of an ash-forming element in the coal, a means for producing a signal related to the intensity of the γ-ray emission and a means responsive to the signal to provide an indication of the concentration of the ash-forming element in the coal

  12. System of HPC content archiving

    Science.gov (United States)

    Bogdanov, A.; Ivashchenko, A.

    2017-12-01

    This work is aimed to develop a system, that will effectively solve the problem of storing and analyzing files containing text data, by using modern software development tools, techniques and approaches. The main challenge of storing a large number of text documents defined at the problem formulation stage, have to be resolved with such functionality as full text search and document clustering depends on their contents. Main system features could be described with notions of distributed multilevel architecture, flexibility and interchangeability of components, achieved through the standard functionality incapsulation in independent executable modules.

  13. Milk Iodine Content in Slovakia

    Directory of Open Access Journals (Sweden)

    I. Paulíková

    2008-01-01

    Full Text Available The aim of this work was to map actual iodine status and its seasonal differences in raw milk of dairy cows, sheep, and goats in various regions of Slovakia. Iodine concentrations were determined in 457 samples of raw milk from dairy cows, 78 samples of sheep, and 16 samples of goat milk collected in various regions of Slovakia from 2002 to 2007. Among all the 457 samples of bovine milk, iodine content below 50 μg l-1 was recorded in 114 samples (24.94%; 294 samples (64.33% ranged between 50 and 200 μg l-1; 19 samples (4.16% from 200 to 500 μg l-1; 17 samples (3.72% between 500 and 1 000 μg l-1, and 13 samples (2.85% showed iodine concentrations over 1 000 μg l-1. regional concentrations showed the highest values in the Western, then Middle and Eastern Slovakia, and the lowest values in Northern Slovakia (p p -1 in 49 sheep (62.8% and in 6 goats below 60 μg l-1 (37.5%, which are indicative of iodine deficiency. When comparing seasonal differences, sheep and goat milk had higher iodine content during the winter feeding period, however, in dairy cows we recorded the opposite ratio. Except for goat milk (p < 0.01 the seasonal differences were not significant.

  14. Content of system design descriptions

    International Nuclear Information System (INIS)

    1998-10-01

    A System Design Description (SDD) describes the requirements and features of a system. This standard provides guidance on the expected technical content of SDDs. The need for such a standard was recognized during efforts to develop SDDs for safety systems at DOE Hazard Category 2 nonreactor nuclear facilities. Existing guidance related to the corresponding documents in other industries is generally not suitable to meet the needs of DOE nuclear facilities. Across the DOE complex, different contractors have guidance documents, but they vary widely from site to site. While such guidance documents are valuable, no single guidance document has all the attributes that DOE considers important, including a reasonable degree of consistency or standardization. This standard is a consolidation of the best of the existing guidance. This standard has been developed with a technical content and level of detail intended to be most applicable to safety systems at DOE Hazard Category 2 nonreactor nuclear facilities. Notwithstanding that primary intent, this standard is recommended for other systems at such facilities, especially those that are important to achieving the programmatic mission of the facility. In addition, application of this standard should be considered for systems at other facilities, including non-nuclear facilities, on the basis that SDDs may be beneficial and cost-effective

  15. Content provision and multi-homing

    OpenAIRE

    Pires, Armando J. Garcia

    2015-01-01

    We analyze the effects of multi-homing consumers on content provision by media firms. We develop a model where media firms compete on content provision and advertising revenues, and consumers enjoy network effects from consuming content that other consumers also consume. Media firms have to choose if they are single-content or multi-content, and in the latter case how much content to offer. Competition for advertising revenues gives a two-sided market nature to our model, since advertisers pr...

  16. 21 CFR 101.60 - Nutrient content claims for the calorie content of foods.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Nutrient content claims for the calorie content of... Claims § 101.60 Nutrient content claims for the calorie content of foods. (a) General requirements. A claim about the calorie or sugar content of a food may only be made on the label or in the labeling of a...

  17. Tie Content in Professional Networks

    DEFF Research Database (Denmark)

    Zarzecka, Olga

    in resource exchanges and the effect of these differences on the number of, and extent to which, resources are provided by a network tie. Chapter 3 explores how firm underperfomance and social identity with corporate elite alter types of resources a network tie provides. Chapter 4 focuses on a tie’s internal......Professional networks of senior managers have indisputable value for them as well as for their organizations. In recent years, much attention has been given to the structure of these networks as it reflects senior managers’ opportunity to access valuable resources. Surprisingly, the actual...... resources that senior managers acquire through their network ties, i.e. the tie content, remain heavily understudied. Hence, the purpose of this dissertation is to answer the following question: What resources flow through informal ties in senior managers’ professional networks, and why? The first chapter...

  18. Information content of poisson images

    International Nuclear Information System (INIS)

    Cederlund, J.

    1979-04-01

    One major problem when producing images with the aid of Poisson distributed quanta is how best to compromise between spatial and contrast resolution. Increasing the number of image elements improves spatial resolution, but at the cost of fewer quanta per image element, which reduces contrast resolution. Information theory arguments are used to analyse this problem. It is argued that information capacity is a useful concept to describe an important property of the imaging device, but that in order to compute the information content of an image produced by this device some statistical properties (such as the a priori probability of the densities) of the object to be depicted must be taken into account. If these statistical properties are not known one cannot make a correct choice between spatial and contrast resolution. (author)

  19. Characteristics and contents of dreams.

    Science.gov (United States)

    Schredl, Michael

    2010-01-01

    Dreams have been studied from different perspectives: psychoanalysis, academic psychology, and neurosciences. After presenting the definition of dreaming and the methodological tools of dream research, the major findings regarding the phenomenology of dreaming and the factors influencing dream content are briefly reviewed. The so-called continuity hypothesis stating that dreams reflect waking-life experiences is supported by studies investigating the dreams of psychiatric patients and patients with sleep disorders, i.e., their daytime symptoms and problems are reflected in their dreams. Dreams also have an effect on subsequent waking life, e.g., on daytime mood and creativity. The question about the functions of dreaming is still unanswered and open to future research. Copyright © 2010 Elsevier Inc. All rights reserved.

  20. Mercury content in Hot Springs

    Energy Technology Data Exchange (ETDEWEB)

    Nakagawa, R

    1974-01-01

    A method of determination of mercury in hot spring waters by flameless atomic absorption spectrophotometry is described. Further, the mercury content and the chemical behavior of the elementary mercury in hot springs are described. Sulfide and iodide ions interfered with the determination of mercury by the reduction-vapor phase technique. These interferences could, however, be minimized by the addition of potassium permanganate. Waters collected from 55 hot springs were found to contain up to 26.0 ppb mercury. High concentrations of mercury have been found in waters from Shimoburo Springs, Aomori (10.0 ppb), Osorezan Springs, Aomori (1.3 approximately 18.8 ppb), Gosyogake Springs, Akita (26.0 ppb), Manza Springs, Gunma (0.30 approximately 19.5 ppb) and Kusatu Springs, Gunma (1.70 approximately 4.50 ppb). These hot springs were acid waters containing a relatively high quantity of chloride or sulfate.

  1. Psychoactive drug advertising: content analysis.

    Science.gov (United States)

    Mastroianni, Patrícia C; Vaz, Amanda Cristina R; Noto, Ana Regina; Galduróz, José Carlos F

    2008-10-01

    The goal of this study was to describe the human figures portrayed in psychoactive drug advertising in terms of gender, age, ethnic group, and social context. Content analysis for 86 new pieces of printed advertisements released in 2005 was carried out. Fisher exact test was used to analyze the association between categories. There was a preponderance of women (62.8%) who were four times more present in advertisements for antidepressants and anxyolitics than men. Most of the people shown were Caucasian (98.8%) young adults (72%). These people were pictured in leisure activities (46.5%), at home (29%), or in contact with nature (16.2%). The message conveyed was that the drugs treat routinely felt subjective symptoms of discomfort, inducing in an irrational appeal that may affect drug prescription.

  2. MATHEMATICAL PROBLEMS OF INTEGRATIVE CONTENTS

    Directory of Open Access Journals (Sweden)

    V. Kushnir

    2014-09-01

    Full Text Available The tasks of integrative content requires the use of knowledge and skills on various themes both one discipline and different disciplines. Mostly in the classroom (or in homework the tasks on the properties absorption of different concepts using different theories are considered. Thus knowledge within only one discipline is formed, knowledge of the narrow sense (one subject. Such knowledge is "prescriptional", we call it idealized. After all, it is far from models of the real professional problems and problems of life in general, in order to solve them it is necessary to apply knowledge and skills acquired in different themes of the same objects,life experience. Practical formation of integrative knowledge requires statement of the educational problems before the subjects of studying, the problems within the "narrow objectivity" can not be resolved at all, or such kind of solving is too difficult to solve, for example, the nature and the context of solving problems (scientific approaches to solving problems, creating mathematical models, methods for solving such models, means of solving, application of methods, analysis of the models solution and the right choice, the inspection of solutions, etc. will sink in the conglomeration of technical operations. The problems with integrative content are usually more complicated than the problems of "narrow objectivity." In our problems the index of such difficulty is the essence of educational content, which is disclosed in the previous paragraph. The problems solution proposed in this article requires knowledge of the structural geometry (circle construction, touching two or three laps: with analytic geometry (method of coordinates on the plane; the distance between two points on the coordinate plane; algebra (system drawing irrational equations, method for solving such system, the solution of the system, analysis of the results and the right choose of the desired solution for found criterion, testing

  3. Angular momentum content of galaxies

    International Nuclear Information System (INIS)

    Shaya, E.J.; Tully, R.B.

    1984-01-01

    A schema of galaxy formation is developed in which the environmental influence of large-scale structure plays a dominant role. This schema was motivated by the observation that the fraction of E and S0 galaxies is much higher in clusters than in low-density regions and by an inference that those spirals that are found in clusters probably have fallen in relatively recently from the low-density regions. It is proposed that the tidal field of the Local Supercluster acts to determine the morphology of galaxies through two complementary mechanisms. In the first place, the supercluster can apply torques to protogalaxies. Galaxies which collapsed while expanding away from the central cluster decoupled from the external tidal field and conserved the angular momentum that they acquired before collapse. Galaxies which formed in the cluster while the cluster collapsed continued to feel the tidal field. In the latter case, the spin of outer collapsing layers can be halted and reversed, and tends to cancel the spin of inner layers. The result is a reduction of the total angular momentum content of the galaxy. In addition, the supercluster tidal field can regulate accretion of fresh material onto the galaxies since the field creates a Roche limit about galaxies and material beyond this limit is lost. Any material that has not collapsed onto a galaxy by the time the galaxy falls into a cluster will be tidally stripped. The angular momentum content of that part of the protogalactic cloud which has not yet collapsed . continues to grow linearly with time due to the continued torquing by the supercluster and neighbors. Galaxies at large distances from the cluster core can continue to accrete this high angular momentum material until the present, but galaxies that enter the cluster are cut off from replenishing material

  4. Ash content of lignites - radiometric analysis

    International Nuclear Information System (INIS)

    Leonhardt, J.; Thuemmel, H.W.

    1986-01-01

    The quality of lignites is governed by the ash content varying in dependence upon the geologic conditions. Setup and function of the radiometric devices being used for ash content analysis in the GDR are briefly described

  5. Digital piracy management in creative content industry

    OpenAIRE

    Akulavičius, Marius

    2015-01-01

    The present habits of digital content consumption and a rather easy access to illegal creative content reduce the opportunities to limit digital piracy by banning or invoking legislation. such a context of the creative content industry results in the need to search for new business models that would encourage users to voluntarily switch from illegal to legal products of the creative content industry, rather than simply banning them from using the illegal ones. iIn order to determine which bus...

  6. Image Retargeting by Content-Aware Synthesis

    OpenAIRE

    Dong, Weiming; Wu, Fuzhang; Kong, Yan; Mei, Xing; Lee, Tong-Yee; Zhang, Xiaopeng

    2014-01-01

    Real-world images usually contain vivid contents and rich textural details, which will complicate the manipulation on them. In this paper, we design a new framework based on content-aware synthesis to enhance content-aware image retargeting. By detecting the textural regions in an image, the textural image content can be synthesized rather than simply distorted or cropped. This method enables the manipulation of textural & non-textural regions with different strategy since they have different...

  7. [Contents of total flavonoids in Rhizoma Arisaematis].

    Science.gov (United States)

    Du, S S; Lin, H Y; Zhou, Y X; Wei, L X

    2001-06-01

    Comparing the contents of total flavonoides of Rhizoma Arisaematis, which collected in different time, regions, different varieties and processed. Determining the contents by ultraviolet spectro-photometry. The contents were found in the following sequence: 1. the end of July, the begin of July, August, September; 2. Beijing, Shanxi, Sichuan, Anhui; 3. Arisaema erubenscens, A. heterophyllum, A. amurense; 4. unprocessed product, processed product.

  8. Enterprise Content Buying--The New Landscape

    Science.gov (United States)

    Noorlander, Bill

    2009-01-01

    Content is both a key ingredient for business and a major expense. Market research shows that the investment in content and data is generally one of the top expense items within a firm. For some firms, within the financial industry, for example, content costs are the second or third level of expense behind the cost of employees. While there has…

  9. Content Area Literacy in the Mathematics Classroom

    Science.gov (United States)

    Armstrong, Abbigail; Ming, Kavin; Helf, Shawnna

    2018-01-01

    Content area literacy has an important role in helping students understand content in specific disciplines, such as mathematics. Although the strategies are not unique to each individual content area, they are often adapted for use in a specific discipline. For example, mathematicians use mathematical language to make sense of new ideas and…

  10. Enabling DRM-preserving Digital content Redistribution

    NARCIS (Netherlands)

    Krishnan Nair, S.; Popescu, B.C.; Gamage, C.D.; Crispo, B.; Tanenbaum, A.S.

    2005-01-01

    Traditionally, the process of online digital content distribution has involved a limited number of centralised distributors selling protected contents and licenses authorising the use of the se contents, to consumers. In this paper, we extend this model by introducing a security scheme that enables

  11. Breast milk nutrient content and infancy growth

    NARCIS (Netherlands)

    Prentice, Philippa; Ong, Ken K.; Schoemaker, Marieke H.; Tol, van Eric A.F.; Vervoort, Jacques; Hughes, Ieuan A.; Acerini, Carlo L.; Dunger, David B.

    2016-01-01

    Aim: Benefits of human breast milk (HM) in avoiding rapid infancy weight gain and later obesity could relate to its nutrient content. We tested the hypothesis that differential HM total calorie content (TCC) or macronutrient contents may be associated with infancy growth. Methods: HM hindmilk

  12. [Relativity among starch quantity, polysaccharides content and total alkaloid content of Dendrobium loddigesii].

    Science.gov (United States)

    Zhu, Hua; Teng, Jianbei; Cai, Yi; Liang, Jie; Zhu, Yilin; Wei, Tao

    2011-12-01

    To find out the relativity among starch quantity, polysaccharides content and total alkaloid content of Dendrobium loddigesii. Microscopy-counting process was applied to starch quantity statistics, sulfuric acid-anthrone colorimetry was used to assay polysaccharides content and bromocresol green colorimetry was used to assay alkaloid content. Pearson product moment correlation analysis, Kendall's rank correlation analysis and Spearman's concordance coefficient analysis were applied to study their relativity. Extremely significant positive correlation was found between starch quantity and polysaccharides content, and significant negative correlation between alkaloid content and starch quantity was discovered, as well was between alkaloid content and polysaccharides content.

  13. Retail Executives’ Professional Learning Contents

    Directory of Open Access Journals (Sweden)

    Eduardo de Aquino Lucena

    2014-05-01

    Full Text Available The research question that is addressed in this article is the following: what do the executives from small retailing firms learn in their work environment? The theoretical framework of the study is based on texts from the field of learning. This is a qualitative investigation. Ten interviews with clothing retail executives were carried out. Later, these interviews were transcribed and analyzed. In the data analysis stage, two categories were established in response to the research question. Regarding the first, respondents perceived difficulties (problems in their work environments and obtained specific information and knowledge in order to deal with these situations. So as to overcome different professional difficulties, respondents learned about colors and types of fabric and about certain manufacturing process aspects referring to the clothing sold by their companies. They also declared to have learned about their companies’ suppliers and about certain issues referring to sales, and to the accounting and the financial management of their companies. The second category refers to a change in some of the respondents’ habits. This learning content refers to predispositions to respond and/ or act in situations at their work environments. Respondents reported having changed the way they related to other people. They emphasized that they had learned how to interact with the employees at their stores and how to carry out supervision. Differently from other studies, we found that the retailers’ learning (individual learning affected their companies’ learning (organizational learning through changes in certain aspects of the analyzed companies’ organizational structures.

  14. The content of compound conditioning.

    Science.gov (United States)

    Harris, Justin A; Andrew, Benjamin J; Livesey, Evan J

    2012-04-01

    In three experiments using Pavlovian conditioning of magazine approach, rats were trained with a compound stimulus, AB, and were concurrently trained with stimulus B on its own. The reinforcement rate of B, rB, was either 1/2, 2/3, or 2/5 of rAB. After extended training, the conditioning strength of A was assessed using probe trials in which A was presented alone. Responding during A was compared with that during AB, B, and a third stimulus, C, for which rC = rAB - rB. In each experiment, the rats' response rate during A was almost identical to that during C (and during B, when rB = 1/2rAB). This suggests that, during AB conditioning, the rats had learned about rA as being equal to [rAB - rB], and implies that the content of their learning was a linear function of r. The findings provide strong support for rate-based models of conditioning (e.g., Gallistel & Gibbon, 2000). They are also consistent with the associative account of learning defined in the Rescorla and Wagner (1972) model, but only if the learning rate during reinforcement equals that during nonreinforcement. (c) 2012 APA, all rights reserved.

  15. An emerging role: the nurse content curator.

    Science.gov (United States)

    Brooks, Beth A

    2015-01-01

    A new phenomenon, the inverted or "flipped" classroom, assumes that students are no longer acquiring knowledge exclusively through textbooks or lectures. Instead, they are seeking out the vast amount of free information available to them online (the very essence of open source) to supplement learning gleaned in textbooks and lectures. With so much open-source content available to nursing faculty, it benefits the faculty to use readily available, technologically advanced content. The nurse content curator supports nursing faculty in its use of such content. Even more importantly, the highly paid, time-strapped faculty is not spending an inordinate amount of effort surfing for and evaluating content. The nurse content curator does that work, while the faculty uses its time more effectively to help students vet the truth, make meaning of the content, and learn to problem-solve. Brooks. © 2014 Wiley Periodicals, Inc.

  16. Plasma catecholamine content using radioenzymatic assay

    International Nuclear Information System (INIS)

    Minami, Masaru; Togashi, Hiroko; Koike, Yuichi; Shimamura, Keiichi; Yamazaki, Noriko

    1980-01-01

    Catecholamine (CA) contents in blood plasma of spontaneously hypertensive rats (SHR) and human blood plasma were measured by radioenzymatic assay (REA) and trihydroxyindol (THI) fluorescent method using high performance liquid chromatography (HPLC), and both measurement methods were compared. The standard curve of REA showed a good linear relationship between total CA contents and separated CA contents. Though there was a danger of exposure to β-ray when REA was performed, this method was useful for measurement of CA contents in blood of small animals and small quantity of blood because CA content of only 50 μg of blood plasma could be measured by this method. Norepinephrine (NE) and epinephrine (E) contents in men with normal blood pressure measured by REA was 250 +- 61 pg/ml and 37 +- 22 pg/ml, respectively. NE and E contents in patients with mild hypertension were 460 +- 128 pg/ml and 50 +- 20 pg/ml, respectively. There was not a significant difference between NE and E contents in men with normal blood pressure and those in patients with mild hypertension. Total CA content in blood plasma of SHR killed by decapitation was 5,000 +- 1,131 pg/ml, which was 5 times NE and E contents in blood plasma obtained from femoral vein of anesthetized SHR (816 +- 215 pg/ml and 209 +- 44 pg/ml). Total CA content in the same sample was measured by REA and HPLC. As a result, total CA content measured by REA was higher than that measured by HPLC, but there was a good relationship between total CA content measured by REA and that measured by HPLC. NE content in men with normal blood pressure measured by HPLC was elevated significantly according to an increase in their age, but this tendency was not observed in patients with hypertension. (Tsunoda, M.)

  17. A Comparison of Selected Supervisory Skills of Content Specialist and Non-Content Specialist University Supervisors

    Science.gov (United States)

    Hunt, Kevin; Mitchell, Murray; Maina, Michael; Griffin, Lisa

    2015-01-01

    The purpose of this study was to describe and contrast selected approaches to the supervision of student teachers between Content Specialist and Non-Content Specialist university supervisors. Content Specialist supervisors were identified as trained university supervisors with a background in physical education. Non-Content Specialist supervisors…

  18. Adolescent judgment of sexual content on television: implications for future content analysis research.

    Science.gov (United States)

    Manganello, Jennifer A; Henderson, Vani R; Jordan, Amy; Trentacoste, Nicole; Martin, Suzanne; Hennessy, Michael; Fishbein, Martin

    2010-07-01

    Many studies of sexual messages in media utilize content analysis methods. At times, this research assumes that researchers and trained coders using content analysis methods and the intended audience view and interpret media content similarly. This article compares adolescents' perceptions of the presence or absence of sexual content on television to those of researchers using three different coding schemes. Results from this formative research study suggest that participants and researchers are most likely to agree with content categories assessing manifest content, and that differences exist among adolescents who view sexual messages on television. Researchers using content analysis methods to examine sexual content in media and media effects on sexual behavior should consider identifying how audience characteristics may affect interpretation of content and account for audience perspectives in content analysis study protocols when appropriate for study goals.

  19. TV content analysis techniques and applications

    CERN Document Server

    Kompatsiaris, Yiannis

    2012-01-01

    The rapid advancement of digital multimedia technologies has not only revolutionized the production and distribution of audiovisual content, but also created the need to efficiently analyze TV programs to enable applications for content managers and consumers. Leaving no stone unturned, TV Content Analysis: Techniques and Applications provides a detailed exploration of TV program analysis techniques. Leading researchers and academics from around the world supply scientifically sound treatment of recent developments across the related subject areas--including systems, architectures, algorithms,

  20. Launching platforms for user-generated content

    OpenAIRE

    Batista, Guilherme Luís Caroço

    2015-01-01

    Field lab: Entrepreneurial and innovative ventures This paper intends to discuss and absorb the Best Practices employed by successful User- Generated Content (UGC)1 platforms and constitute a guide on how to launch a platform without having a cyclical lack of content and users. Research shows that companies have resorted to integration with mature UGC platforms, and providing content by themselves, in an initial state. I conclude that integration possibilities should be explore...

  1. Quantification of Fluorine Content in AFFF Concentrates

    Science.gov (United States)

    2017-09-29

    for MilSpec compliance. Fluorocarbon surfactants are the most active components in these concentrates, and analysis of the fluorine content in the... physical requirements for AFFF concentrates includes a total fluorine content determination and a requirement for subsequent evaluations of this AFFF...the standard for fluorine content as well as the reference for chemical shift. For preparation of an NMR solution, it is important that the TFE

  2. Bioactive content, hepatoprotective and antioxidant activities of ...

    African Journals Online (AJOL)

    Bioactive content, hepatoprotective and antioxidant activities of whole plant extract of Micromeria fruticosa (L) Druce ssp Serpyllifolia F Lamiaceae against Carbon tetrachloride-induced hepatotoxicity in mice.

  3. Effect of irradiation on carbohydrates content

    International Nuclear Information System (INIS)

    Chantharasakul, S.

    1971-01-01

    Effect of gamma radiation on vitamin C and total acidity contents of Hom Tong banana was described. There was a slight decrease in vitamin C contents in both irradiated and non-irradiated banana during storage. No difference was detected in term of vitamin C contents between irradiated and non-irradiated banana at any storage time. The total acidity of the banana increased with increasing time of storage owing to the ripening effect of the fruit. Higher total acidity content of non-irradiated banana during storage indicated the faster rate of ripening of the fruit

  4. Content-Based Personalization Services Integrating Folksonomies

    Science.gov (United States)

    Musto, Cataldo; Narducci, Fedelucio; Lops, Pasquale; de Gemmis, Marco; Semeraro, Giovanni

    Basic content-based personalization consists in matching up the attributes of a user profile, in which preferences and interests are stored, with the attributes of a content object. The Web 2.0 (r)evolution has changed the game for personalization, from ‘elitary’ Web 1.0, written by few and read by many, to web content generated by everyone (user-generated content - UGC), since the role of people has evolved from passive consumers of information to that of active contributors.

  5. Proximate composition and antinutrient content of pumpkin ...

    African Journals Online (AJOL)

    Proximate composition and antinutrient content of pumpkin ( Cucurbita pepo ) and sorghum ( Sorghum bicolor ) flour blends fermented with Lactobacillus plantarum , Aspergillus niger and Bacillus subtilis.

  6. Content Propagation in Online Social Networks

    NARCIS (Netherlands)

    Blenn, N.

    2014-01-01

    This thesis presents methods and techniques to analyze content propagation within online social networks (OSNs) using a graph theoretical approach. Important factors and different techniques to analyze and describe content propagation, starting from the smallest entity in a network, representing a

  7. 27 CFR 5.37 - Alcohol content.

    Science.gov (United States)

    2010-04-01

    ... label may also state the alcohol content in degrees of proof if this information appears in direct... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Alcohol content. 5.37... OF THE TREASURY LIQUORS LABELING AND ADVERTISING OF DISTILLED SPIRITS Labeling Requirements for...

  8. Polyphenols content, antioxidant and antimicrobial activities of ...

    African Journals Online (AJOL)

    25 wild plants were collected from the south of Tunisia. The dried aerial parts were extracted under a continuous reflux set-up in a Soxhlet extractor with hexane, ethyl acetate, methanol and water. The extracts were screened for total phenolic content, antioxidant and antimicrobial activities. Total phenolic contents were ...

  9. Determining fissile content of nuclear fuel elements

    International Nuclear Information System (INIS)

    Arya, S.P.; Grossman, L.N.; Schoenig, F.C.

    1980-01-01

    This invention relates to the determination of the fissile fuel content of fuel for nuclear reactors. A nondestructive method is described for determining rapidly, accurately and simultaneously the fissile content, enrichment and location of fuel material which may also contain amounts of burnable poison, by detecting the γ-rays emitted from the fuel material due to natural radioactive decay. (U.K.)

  10. 10 Budget-Savvy Content Management Strategies

    Science.gov (United States)

    Hillis, David J.

    2004-01-01

    Facing an overall budget reduction of 10 percent, most colleges or universities would postpone investing in a Web content management system. However, for California State University Monterey Bay (CSUMB), a large budget cut made Web content management even more important. CSUMB found an innovative way to purchase and implement a new Content…

  11. Chemical composition, true metabolisable energy content and ...

    African Journals Online (AJOL)

    The physical characteristics (thousand seed and hectolitre mass), chemical composition (dry matter, ash, crude protein (CP), ether extract, acid detergent fibre, neutral detergent fibre and mineral content), energy values (nitrogen corrected true metabolisable energy content (TMEn for roosters)) as well as the lysine and ...

  12. Teaching Content Analysis through "Harry Potter"

    Science.gov (United States)

    Messinger, Adam M.

    2012-01-01

    Content analysis is a valuable research tool for social scientists that unfortunately can prove challenging to teach to undergraduate students. Published classroom exercises designed to teach content analysis have thus far been predominantly envisioned as lengthy projects for upper-level courses. A brief and engaging exercise may be more…

  13. 36 CFR 294.14 - Petition contents.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Petition contents. 294.14... State Petitions for Inventoried Roadless Area Management § 294.14 Petition contents. (a) Any petition... particular lands for which the petition is being made, including maps and other appropriate resources in...

  14. Stopping Web Plagiarists from Stealing Your Content

    Science.gov (United States)

    Goldsborough, Reid

    2004-01-01

    This article gives tips on how to avoid having content stolen by plagiarists. Suggestions include: using a Web search service such as Google to search for unique strings of text at the individuals site to uncover other sites with the same content; buying a infringement-detection program; or hiring a public relations firm to do the work. There are…

  15. Taurine content of tissues of irradiated rats

    International Nuclear Information System (INIS)

    Akhalaya, M.Ya.; Bogatyrev, G.P.; Kudryashov, Yu.B.; Yartsev, E.I.

    1976-01-01

    The taurine content of tissues (liver, stomach, small intestine and spleen) of rats irradiated with doses of 700 and 450 rads has been studied. Phase changes have been found in the taurine content of radiosensitive tissues in the course of radiation injury development

  16. Familiarity with Content and Syllogistic Reasoning.

    Science.gov (United States)

    Mast, Terrill A.; And Others

    Forty-four education and 44 dental students were administered a 30-item syllogism test containing five syllogic forms six times repeated in three different content forms--technical dental terms, common dental terms, and content-free (letters). Data were analyzed using a two-factor with repeated measures on one factor design. It was found that…

  17. 49 CFR 37.139 - Plan contents.

    Science.gov (United States)

    2010-10-01

    ..., absence of restrictions or priorities based on trip purpose, response time, fares, hours and days of... 49 Transportation 1 2010-10-01 2010-10-01 false Plan contents. 37.139 Section 37.139... DISABILITIES (ADA) Paratransit as a Complement to Fixed Route Service § 37.139 Plan contents. Each plan shall...

  18. Type B Package Radioactive Material Contents Compliance

    International Nuclear Information System (INIS)

    HENSEL, STEVE

    2006-01-01

    Implementation of packaging and transportation requirements can be subdivided into three categories; contents compliance, packaging closure, and transportation or logistical compliance. This paper addresses the area of contents compliance within the context of regulations, DOE Orders, and appropriate standards. Common practices and current pitfalls are also discussed

  19. Content in Context Improves Deception Detection Accuracy

    Science.gov (United States)

    Blair, J. Pete; Levine, Timothy R.; Shaw, Allison S.

    2010-01-01

    Past research has shown that people are only slightly better than chance at distinguishing truths from lies. Higher accuracy rates, however, are possible when contextual knowledge is used to judge the veracity of situated message content. The utility of content in context was shown in a series of experiments with students (N = 26, 45, 51, 25, 127)…

  20. Flavonoid, hesperidine, total phenolic contents and antioxidant ...

    African Journals Online (AJOL)

    Additionally, the antioxidant activities were also determined by ferric reducing antioxidant power (FRAP) and 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity. C. hystrix had the highest flavonoid and total phenolic contents while C. aurantifolia had the highest hesperidine content. The antioxidant activity of ...

  1. Wave liquefaction in soils with clay content

    DEFF Research Database (Denmark)

    Kirca, Özgür; Sumer, B. Mutlu; Fredsøe, Jørgen

    2012-01-01

    The paper presents the results of an experimental study of the influence of clay content (in silt-clay and sand-clay mixtures) on liquefaction beneath progressive waves. The experiments showed that the influence of clay content is very significant. Susceptibility of silt to liquefaction is increa...

  2. Construct Validation of Content Standards for Teaching

    Science.gov (United States)

    van der Schaaf, Marieke F.; Stokking, Karel M.

    2011-01-01

    Current international demands to strengthen the teaching profession have led to an increased development and use of professional content standards. The study aims to provide insight in the construct validity of content standards by researching experts' underlying assumptions and preferences when participating in a delphi method. In three rounds 21…

  3. 238U content in soils of Byelorussia

    International Nuclear Information System (INIS)

    Shagalova, Eh.D.

    1986-01-01

    Results of detection in Byelorussian soils of a heavy natural radionuclide 238 U and its content in humus horizons of the soils on map-schemes are presented. 238 U content is determined by complete decomposition of soils by acids, isolation from thorium using EhDEh-10 P anionite and subsequent solution colorimetry. It is shown that the content of uranium-238 in soils decreases from the North to the South. Its maximum amount (>2x10 -4 %) is detected in turfy-podsolic soils in lake-glacier loams; the minimum one ( -4 %)- in peatymarshy soils. The map-scheme of 238 U content is a background base. Using the background base it is possible to trace the change in uranium content in soils under conditions of technogenic effect and to substantiate the efficiency of environment protection measures

  4. Changes in Hydrogen Content During Steelmaking

    Directory of Open Access Journals (Sweden)

    Vrbek K.

    2015-04-01

    Full Text Available Štore Steel produces steel grades for spring, forging and engineering industry applications. Steelmaking technology consists of scrap melting in Electric Arc Furnace (EAF, secondary metallurgy in Ladle Furnace (LF and continuous casting of billets (CC. Hydrogen content during steelmaking of various steel grades and steelmaking technologies was measured. Samples of steel melt from EAF, LF and CC were collected and investigated. Sampling from Electric Arc Furnace and Ladle Furnace was carried out using vacuum pin tubes. Regular measurements of hydrogen content in steel melt were made using Hydris device. Hydrogen content results measured in tundish by Hydris device were compared with results from pin tube samples. Based on the measurement results it was established that hydrogen content during steelmaking increases. The highest values were determined in tundish during casting. Factors that influence the hydrogen content in liquid steel the most were steelmaking technology and alloying elements.

  5. Germanium content in Polish hard coals

    Directory of Open Access Journals (Sweden)

    Makowska Dorota

    2016-01-01

    Full Text Available Due to the policy of the European Union, it is necessary to search for new sources of scarce raw materials. One of these materials is germanium, listed as a critical element. This semi-metal is widely used in the electronics industry, for example in the production of semiconductors, fibre optics and solar cells. Coal and fly ash from its combustion and gasification for a long time have been considered as a potential source of many critical elements, particularly germanium. The paper presents the results of germanium content determination in the Polish hard coal. 23 coal samples of various coal ranks were analysed. The samples were collected from 15 mines of the Upper Silesian Coal Basin and from one mine of the Lublin Coal Basin. The determination of germanium content was performed with the use of Atomic Absorption Spectrometry with Electrothermal Atomization (GFAAS. The investigation showed that germanium content in the analysed samples was at least twice lower than the average content of this element in the hard coals analysed so far and was in the range of 0.08 ÷ 1.28 mg/kg. Moreover, the content of Ge in the ashes from the studied coals does not exceed 15 mg/kg, which is lower than the average value of Ge content in the coal ashes. The highest content of this element characterizes coals of the Lublin Coal Basin and young coals type 31 from the Vistula region. The results indicate a low utility of the analysed coal ashes as a source of the recovery of germanium. On the basis of the analyses, the lack of the relationship between the content of the element and the ash content in the tested coals was noted. For coals of the Upper Silesian Coal Basin, the relationship between the content of germanium in the ashes and the depth of the seam was observed.

  6. Influence of Content Knowledge on Pedagogical Content Knowledge: The Case of Teaching Photosynthesis and Plant Growth

    Science.gov (United States)

    Kapyla, Markku; Heikkinen, Jussi-Pekka; Asunta, Tuula

    2009-01-01

    The aim of the research was to investigate the effect of the amount and quality of content knowledge on pedagogical content knowledge (PCK). The biological content photosynthesis and plant growth was used as an example. The research sample consisted of 10 primary and 10 secondary (biology) teacher students. Questionnaires, lesson preparation task…

  7. What's More Important--Literacy or Content? Confronting the Literacy-Content Dualism

    Science.gov (United States)

    Draper, Roni Jo; Smith, Leigh K.; Hall, Kendra M.; Siebert, Daniel

    2005-01-01

    The literacy-content dualism, which suggests that teachers must decide whether to provide literacy or content instruction, is a false dualism and adherence to it is detrimental to student participation in content-area reasoning, learning, and communicating. This article describes the experiences that prompted the teacher educators who authored…

  8. Observation of radon content in soil gas

    International Nuclear Information System (INIS)

    Mino, Kazuo; Nishimura, Susumu

    1979-01-01

    For earthquake prediction, precursory phenomena before the large earthquakes have been investigated in many countries. In China and some other places, they made a success of predictions of the large earthquakes by catching precursory phenomena. Variation of Radon content of underground gas and water is also one of those phenomena. In our country, the decrease of Radon content was observed several days before the large earthquake which occured near Izu Peninsula on January, 14, 1978. We also begin to observe variation of Radon content of underground gas. The purpose of our observation is a study on the Radon gas content before and after earthquakes. According to the results of the test investigation, the change of atmospheric pressure is mutually related with variation of Radon content in soil gas. Effect of atmospheric pressure is about one Eman, which is significant value comparison with the change, before the large earthquake, a few or several Emans. But, when correction of atmospheric pressure's effect was done, the change of Radon content maybe decrease 5/100 Emans. Above result tells the possibility of detecting the precursor of large earthquake, if Radon content change was over a few Emans. (author)

  9. Quantification of Cannabinoid Content in Cannabis

    Science.gov (United States)

    Tian, Y.; Zhang, F.; Jia, K.; Wen, M.; Yuan, Ch.

    2015-09-01

    Cannabis is an economically important plant that is used in many fields, in addition to being the most commonly consumed illicit drug worldwide. Monitoring the spatial distribution of cannabis cultivation and judging whether it is drug- or fiber-type cannabis is critical for governments and international communities to understand the scale of the illegal drug trade. The aim of this study was to investigate whether the cannabinoids content in cannabis could be spectrally quantified using a spectrometer and to identify the optimal wavebands for quantifying the cannabinoid content. Spectral reflectance data of dried cannabis leaf samples and the cannabis canopy were measured in the laboratory and in the field, respectively. Correlation analysis and the stepwise multivariate regression method were used to select the optimal wavebands for cannabinoid content quantification based on the laboratory-measured spectral data. The results indicated that the delta-9-tetrahydrocannabinol (THC) content in cannabis leaves could be quantified using laboratory-measured spectral reflectance data and that the 695 nm band is the optimal band for THC content quantification. This study provides prerequisite information for designing spectral equipment to enable immediate quantification of THC content in cannabis and to discriminate drug- from fiber-type cannabis based on THC content quantification in the field.

  10. Procedural Content Generation: Concepts and Related Works

    Directory of Open Access Journals (Sweden)

    MARIÑO, J. R. H.

    2016-12-01

    Full Text Available The digital games market is growing every year and game development is becoming increasingly complex. Thus, scalability in content generation may require the work of a team with hundreds of people. Procedural Content Generation (PCG comes as an alternative to decrease costs and accelerate the process of game production by creating content automatically or semi-automatically. This article presents some concepts and reviews works developed in PCG, aiming to provide a starting point for those interested in learning and going deeper in the subject of PCG for digital games.

  11. Towards Player-Driven Procedural Content Generation

    DEFF Research Database (Denmark)

    Shaker, Noor; Yannakakis, Georgios N.; Togelius, Julian

    2012-01-01

    Generating immersive game content is one of the ultimate goals for a game designer. This goal can be achieved by realizing the fact that players’ perception of the same game differ according to a number of factors including: players’ personality, playing styles, expertise and culture background....... While one player might find the game immersive, others may quit playing as a result of encountering a seemingly insoluble problem. One promising avenue towards optimizing the gameplay experience for individual game players is to tailor player experience in real-time via automatic game content generation......-driven content generation....

  12. Remote-Handled Transuranic Content Codes

    International Nuclear Information System (INIS)

    2001-01-01

    The Remote-Handled Transuranic (RH-TRU) Content Codes (RH-TRUCON) document represents the development of a uniform content code system for RH-TRU waste to be transported in the 72-Bcask. It will be used to convert existing waste form numbers, content codes, and site-specific identification codes into a system that is uniform across the U.S. Department of Energy (DOE) sites.The existing waste codes at the sites can be grouped under uniform content codes without any lossof waste characterization information. The RH-TRUCON document provides an all-encompassing description for each content code and compiles this information for all DOE sites. Compliance with waste generation, processing, and certification procedures at the sites (outlined in this document foreach content code) ensures that prohibited waste forms are not present in the waste. The content code gives an overall description of the RH-TRU waste material in terms of processes and packaging, as well as the generation location. This helps to provide cradle-to-grave traceability of the waste material so that the various actions required to assess its qualification as payload for the 72-B cask can be performed. The content codes also impose restrictions and requirements on the manner in which a payload can be assembled. The RH-TRU Waste Authorized Methods for Payload Control (RH-TRAMPAC), Appendix 1.3.7 of the 72-B Cask Safety Analysis Report (SAR), describes the current governing procedures applicable for the qualification of waste as payload for the 72-B cask. The logic for this classification is presented in the 72-B Cask SAR. Together, these documents (RH-TRUCON, RH-TRAMPAC, and relevant sections of the 72-B Cask SAR) present the foundation and justification for classifying RH-TRU waste into content codes. Only content codes described in thisdocument can be considered for transport in the 72-B cask. Revisions to this document will be madeas additional waste qualifies for transport. Each content code uniquely

  13. Lead and cadmium content of spices

    Energy Technology Data Exchange (ETDEWEB)

    Bielig, H J; Dreyer, H; Askar, A

    1977-02-02

    The lead and cadmium content of various spices was determined by flameless atomic absorption (AAS). With the exception of one sample, the lead content was lower than 5 ppm, averaging a value of 2,2 ppm Pb. Thus, the maximum permissible level of 5 ppm Pb as recommended by different DIN standards, is not exceeded. The cadmium content was - except for one sample - lower than 0,5 ppm averaging a value of 0,23 ppm Cd. It can be assumed, that by spicing our dishes, the ingestion of lead and cadmium stays at a low level.

  14. Framework for Enabling User-Generated Content

    OpenAIRE

    Nilsson, Karin H

    2012-01-01

    User-generated content, UGC, is a modern topic today and refers to media and creative works created by Internet users and posted on the Internet. More and more application developers wants to offer sharing functionalities in their applications and on their websites. The alternatives of doing so today are to use UGC platforms API, like Facebook and Twitter, to upload the content to that specific platform or to implement the framework ShareKit that enables the user to share their content on mul...

  15. Characterization of Cloud Water-Content Distribution

    Science.gov (United States)

    Lee, Seungwon

    2010-01-01

    The development of realistic cloud parameterizations for climate models requires accurate characterizations of subgrid distributions of thermodynamic variables. To this end, a software tool was developed to characterize cloud water-content distributions in climate-model sub-grid scales. This software characterizes distributions of cloud water content with respect to cloud phase, cloud type, precipitation occurrence, and geo-location using CloudSat radar measurements. It uses a statistical method called maximum likelihood estimation to estimate the probability density function of the cloud water content.

  16. Contents of /sup 210/Pb in food

    Energy Technology Data Exchange (ETDEWEB)

    Huang, X; Song, H

    1982-02-01

    The contents of /sup 210/Pb in 30 kinds of commonly used foods are given in the paper. After the radioactive equilibrium between /sup 210/Pb and /sup 210/Pb was nearly established in samples, the concentration of /sup 210/Pb was determined by the method of spontaneous deposition on silver disc. The contents of /sup 210/Pb then were calculated from that of /sup 210/Po. The average contents of /sup 210/Pb in corn, vegetable and meat were 0.14, 15.08 and 1.26 x 10/sup -14/ Ci/g respectively.

  17. Spatial data content standards for Africa

    CSIR Research Space (South Africa)

    Cooper, Antony K

    2005-11-01

    Full Text Available , they selected 14 standards containing data dictionaries or feature catalogues, and compared their feature types. They have also provided some advice and recommendations on data content standards (particularly for data dictionaries and feature catalogues...

  18. Essential oil content and composition of aniseed

    Directory of Open Access Journals (Sweden)

    Aćimović Milica G.

    2015-01-01

    Full Text Available The field experiments were carried out during 2011 and 2012 in three localities in Vojvodina (Serbia with the application of six different fertilizer regimes aimed at determining the content and composition of the aniseed essential oil. It was found that the average essential oil content of aniseed, obtained by hydrodistillation, was 3.72%. The weather conditions during the year and the locality had a statistically significant effect on the essential oil content, while different source of fertilizers was not statistically significant for the essential oil content and its composition. Essential oil composition was determined using GC-MS technique, and a total of 15 compounds were identified. It was found that the major component was trans-anethole, 94.78% on the average, and the coefficient of variation was 2%. The second most abundant component was γ-himachalene with 2.53% (CV 28%. All other components were present in less than 1%.

  19. Multimedia content management in MPEG-21 framework

    Science.gov (United States)

    Smith, John R.

    2002-07-01

    MPEG-21 is an emerging standard from MPEG that specifies a framework for transactions of multimedia content. MPEG-21 defines the fundamental concept known as a digital item, which is the unit of transaction in the multimedia framework. A digital item can be used to package content for such as a digital photograph, a video clip or movie, a musical recording with graphics and liner notes, a photo album, and so on. The packaging of the media resources, corresponding identifiers, and associated metadata is provided in the declaration of the digital item. The digital item declaration allows for more effective transaction, distribution, and management of multimedia content and corresponding metadata, rights expressions, variations of media resources. In this paper, we describe various challenges for multimedia content management in the MPEG-21 framework.

  20. Learning content and the creative cloud

    NARCIS (Netherlands)

    Specht, Marcus

    2012-01-01

    Specht, M. (2012, 18 April). Learning content and the creative cloud. Presentation given at the workshop for creative cloud CLICK workshop Faculteit Bouwkunde & Architectuur TU Delft, Delft, The Netherlands.

  1. Apple wine processing with different nitrogen contents

    Directory of Open Access Journals (Sweden)

    Aline Alberti

    2011-06-01

    Full Text Available The aim of this work was to evaluate the nitrogen content in different varieties of apple musts and to study the effect of different nitrogen concentrations in apple wine fermentation. The average total nitrogen content in 51 different apples juices was 155.81 mg/L, with 86.28 % of the values above 100 mg/L. The apple must with 59.0, 122.0 and 163.0 mg/L of total nitrogen content showed the maximum population of 2.05x 10(7; 4.42 x 10(7 and 8.66 x 10(7 cell/mL, respectively. Therefore, the maximum fermentation rates were dependent on the initial nitrogen level, corresponding to 1.4, 5.1 and 9.2 g/L.day, respectively. The nitrogen content in the apple musts was an important factor of growth and fermentation velocity.

  2. Towards Player-Driven Procedural Content Generation

    DEFF Research Database (Denmark)

    Shaker, Noor

    Generating immersive game content is one of the ultimate goals for a game designer. This goal can be achieved taken into account that players’ perceptions of the same game differ according to a number of factors including: players’ personality, playing styles, expertise and cultural background. One...... promising avenue towards optimizing the gameplay experience for individual game players - and thereby attempt to close the affective loop in games - is to automatically tailor the game content in real-time. To realize player-driven procedural content generation one needs to specify the aspects of the game...... that have a key influence on the gameplay experience, identify the relationship between these aspects and player experience and define a mechanism for tailoring the game content to each individual needs. In this dissertation we attempt to address the following research questions towards the aim...

  3. 39 CFR 3030.10 - Complaint contents.

    Science.gov (United States)

    2010-07-01

    ... Initial Pleadings § 3030.10 Complaint contents. (a) A complaint must: (1) Set forth the facts and... to be similarly affected by the issues involved in the complaint, if applicable; (5) State the nature...

  4. Swordfish Stomach Content Data, 1989-2000

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Stomach contents were tabulated for 734 swordfish (Xiphias gladius) from the central North Pacific from 1989 to 2000 (most from 1994-1998). The swordfish were...

  5. INFORMATION SYSTEMS AUDIT CURRICULA CONTENT MATCHING

    Directory of Open Access Journals (Sweden)

    Vasile-Daniel CARDOȘ

    2014-11-01

    Full Text Available Financial and internal auditors must cope with the challenge of performing their mission in technology enhanced environment. In this article we match the information technology description found in the International Federation of Accountants (IFAC and the Institute of Internal Auditors (IIA curricula against the Model Curriculum issued by the Information Systems Audit and Control Association (ISACA. By reviewing these three curricula, we matched the content in the ISACA Model Curriculum with the IFAC International Education Practice Statement 2 and the IIAs’ Global Model Internal Audit Curriculum. In the IFAC and IIA Curriculum there are 16 content elements, out of 19 possible, which match, in their description, the ISACA Model Curriculum’s content. We noticed that a candidate who graduates an IFAC or IIA compliant program acquire IS auditing competences similar to the specific content of the ISACA model curriculum but less than the requirements for a professional information systems auditor.

  6. The CODESRIA Bulletin: A Content Analysis

    African Journals Online (AJOL)

    Prof

    the major question that guides this essay is the following: What do articles in the. CODESRIA ... A qualitative and quantitative analysis of the contents of the articles can ..... and elections, child and youth, race, gender, and academic freedom.

  7. Soundtrack contents and depicted sexual violence.

    Science.gov (United States)

    Pfaus, J G; Myronuk, L D; Jacobs, W J

    1986-06-01

    Male undergraduates were exposed to a videotaped depiction of heterosexual rape accompanied by one of three soundtracks: the original soundtrack (featuring dialogue and background rock music), relaxing music, or no sound. Subjective reports of sexual arousal, general enjoyment, perceived erotic content, and perceived pornographic content of the sequence were then provided by each subject. Results indicated that males exposed to the videotape accompanied by the original soundtrack found the sequence significantly more pornographic than males exposed to the sequence accompanied by either relaxing background music or no sound. Ratings of sexual arousal, general enjoyment, and the perceived erotic content, however, did not differ significantly across soundtrack conditions. These results are compatible with the assertion that the content of a video soundtrack may influence the impact of depicted sexual violence.

  8. Validity evidence based on test content.

    Science.gov (United States)

    Sireci, Stephen; Faulkner-Bond, Molly

    2014-01-01

    Validity evidence based on test content is one of the five forms of validity evidence stipulated in the Standards for Educational and Psychological Testing developed by the American Educational Research Association, American Psychological Association, and National Council on Measurement in Education. In this paper, we describe the logic and theory underlying such evidence and describe traditional and modern methods for gathering and analyzing content validity data. A comprehensive review of the literature and of the aforementioned Standards is presented. For educational tests and other assessments targeting knowledge and skill possessed by examinees, validity evidence based on test content is necessary for building a validity argument to support the use of a test for a particular purpose. By following the methods described in this article, practitioners have a wide arsenal of tools available for determining how well the content of an assessment is congruent with and appropriate for the specific testing purposes.

  9. Deploying Content Management System to enhance State ...

    African Journals Online (AJOL)

    PROF. O. E. OSUAGWU

    2013-09-01

    Sep 1, 2013 ... Abstract. Governments across developing countries worldwide have the ... KEYWORDS: Content Management, E-governance, Model, Search engine, ICT. ..... Benchmarking E-government (2002): A Global Perspective, United.

  10. Analysis, Retrieval and Delivery of Multimedia Content

    CERN Document Server

    Cavallaro, Andrea; Leonardi, Riccardo; Migliorati, Pierangelo

    2013-01-01

    Covering some of the most cutting-edge research on the delivery and retrieval of interactive multimedia content, this volume of specially chosen contributions provides the most updated perspective on one of the hottest contemporary topics. The material represents extended versions of papers presented at the 11th International Workshop on Image Analysis for Multimedia Interactive Services, a vital international forum on this fast-moving field. Logically organized in discrete sections that approach the subject from its various angles, the content deals in turn with content analysis, motion and activity analysis, high-level descriptors and video retrieval, 3-D and multi-view, and multimedia delivery. The chapters cover the finest detail of emerging techniques such as the use of high-level audio information in improving scene segmentation and the use of subjective logic for forensic visual surveillance. On content delivery, the book examines both images and video, focusing on key subjects including an efficient p...

  11. Application of the technological, pedagogical, and content ...

    African Journals Online (AJOL)

    Application of the technological, pedagogical, and content knowledge framework in a positivist study on the use of ICT in pedagogy by teachers of mathematical disciplines at Makerere University: a conceptual paper.

  12. US-Total Electron Content Product (USTEC)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The US Total Electron Content (US-TEC) product is designed to specify TEC over the Continental US (CONUS) in near real-time. The product uses a Kalman Filter data...

  13. Advertising effectiveness: the role of content

    OpenAIRE

    Becker , Maren

    2017-01-01

    Despite its long-standing history and many strong findings, research on advertising effectiveness still ranks high on the academic and practitioner agenda. With respect to the influence of advertising on sales, existing econometric response models mostly focus on the impact of advertising spending and scheduling. Comparatively less attention has been devoted to the specific advertising content. Even though, choosing appropriate content cues that grab consumers’ attention and persuade them bec...

  14. Copper content in blood of Uzbek population

    International Nuclear Information System (INIS)

    Mikhol'skaya, I.N.; Agzamova, S.S.; Kutyakova, T.Yu.; Osinskaya, N.S.

    1990-01-01

    The content of copper in blood of Uzbekistan population, depending on place of residence, sex and age was studied to solve certain medicobiological problems. The method of neutron activation with radiochemcial isolation was employed for the analysis. According to the data obtained average content of copper for the points in the republic selected for men and women of different age groups were calculated. 5 refs

  15. USER GENERATED CONTENT IN TOURISM MARKETING

    OpenAIRE

    ALİKILIÇ, Dr. Özlem

    2008-01-01

    This article is based on the idea that user generated content is of fundamental importance in tourism and travel industry to understand the role of consumer generated messages. This paper also describes interpersonal influences mean for user generated content and also word of mouth (WOM) which reflect cost effective for tourism and travel industry but as well as the real crisis lead by the customer and discusses the new technological and ethical considerations facing tourism and travel industry

  16. An Equilibrium Model of User Generated Content

    OpenAIRE

    Dae-Yong Ahn; Jason A. Duan; Carl F. Mela

    2011-01-01

    This paper considers the joint creation and consumption of content on user generated content platforms (e.g., reviews or articles, chat, videos, etc.). On these platforms, users' utilities depend upon the participation of others; hence, users' expectations regarding the participation of others on the site becomes germane to their own involvement levels. Yet these beliefs are often assumed to be fixed. Accordingly, we develop a dynamic rational expectations equilibrium model of joint consumpti...

  17. Are delusional contents replayed during dreams?

    Science.gov (United States)

    D'Agostino, Armando; Aletti, Giacomo; Carboni, Martina; Cavallotti, Simone; Limosani, Ivan; Manzone, Marialaura; Scarone, Silvio

    2013-09-01

    The relationship between dream content and waking life experiences remains difficult to decipher. However, some neurobiological findings suggest that dreaming can, at least in part, be considered epiphenomenal to ongoing memory consolidation processes in sleep. Both abnormalities in sleep architecture and impairment in memory consolidation mechanisms are thought to be involved in the development of psychosis. The objective of this study was to assess the continuity between delusional contents and dreams in acutely psychotic patients. Ten patients with a single fixed and recurring delusional content were asked to report their dreams during an acute psychotic break. Sixteen judges with four different levels of acquaintance to the specific content of the patients' delusions were asked to group the dreams, expecting that fragments of the delusional thought would guide the task. A mathematical index (f,t) was developed in order to compare correct groupings between the four groups of judges. Most judges grouped the dreams slightly above chance level and no relevant differences could be found between the four groups [F(3,12)=1.297; p=n.s.]. Scoring of dreams for specific delusional themes suggested a continuity in terms of dream and waking mentation for two contents (Grandiosity and Religion). These findings seem to suggest that at least some delusional contents recur within patients' dreams. Future studies will need to determine whether such continuity reflects ongoing consolidation processes that are relevant to current theories of delusion formation and stabilization. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Summarizing Audiovisual Contents of a Video Program

    Science.gov (United States)

    Gong, Yihong

    2003-12-01

    In this paper, we focus on video programs that are intended to disseminate information and knowledge such as news, documentaries, seminars, etc, and present an audiovisual summarization system that summarizes the audio and visual contents of the given video separately, and then integrating the two summaries with a partial alignment. The audio summary is created by selecting spoken sentences that best present the main content of the audio speech while the visual summary is created by eliminating duplicates/redundancies and preserving visually rich contents in the image stream. The alignment operation aims to synchronize each spoken sentence in the audio summary with its corresponding speaker's face and to preserve the rich content in the visual summary. A Bipartite Graph-based audiovisual alignment algorithm is developed to efficiently find the best alignment solution that satisfies these alignment requirements. With the proposed system, we strive to produce a video summary that: (1) provides a natural visual and audio content overview, and (2) maximizes the coverage for both audio and visual contents of the original video without having to sacrifice either of them.

  19. Using the DOM Tree for Content Extraction

    Directory of Open Access Journals (Sweden)

    David Insa

    2012-10-01

    Full Text Available The main information of a webpage is usually mixed between menus, advertisements, panels, and other not necessarily related information; and it is often difficult to automatically isolate this information. This is precisely the objective of content extraction, a research area of widely interest due to its many applications. Content extraction is useful not only for the final human user, but it is also frequently used as a preprocessing stage of different systems that need to extract the main content in a web document to avoid the treatment and processing of other useless information. Other interesting application where content extraction is particularly used is displaying webpages in small screens such as mobile phones or PDAs. In this work we present a new technique for content extraction that uses the DOM tree of the webpage to analyze the hierarchical relations of the elements in the webpage. Thanks to this information, the technique achieves a considerable recall and precision. Using the DOM structure for content extraction gives us the benefits of other approaches based on the syntax of the webpage (such as characters, words and tags, but it also gives us a very precise information regarding the related components in a block, thus, producing very cohesive blocks.

  20. A study of real-time content marketing : formulating real-time content marketing based on content, search and social media

    OpenAIRE

    Nguyen, Thi Kim Duyen

    2015-01-01

    The primary objective of this research is to understand profoundly the new concept of content marketing – real-time content marketing on the aspect of the digital marketing experts. Particularly, the research will focus on the real-time content marketing theories and how to build real-time content marketing strategy based on content, search and social media. It also finds out how marketers measure and keep track of conversion rates of their real-time content marketing plan. Practically, th...

  1. Increased cerebral water content in hemodialysis patients.

    Directory of Open Access Journals (Sweden)

    Kathrin Reetz

    Full Text Available Little information is available on the impact of hemodialysis on cerebral water homeostasis and its distribution in chronic kidney disease. We used a neuropsychological test battery, structural magnetic resonance imaging (MRI and a novel technique for quantitative measurement of localized water content using 3T MRI to investigate ten hemodialysis patients (HD on a dialysis-free day and after hemodialysis (2.4±2.2 hours, and a matched healthy control group with the same time interval. Neuropsychological testing revealed mainly attentional and executive cognitive dysfunction in HD. Voxel-based-morphometry showed only marginal alterations in the right inferior medial temporal lobe white matter in HD compared to controls. Marked increases in global brain water content were found in the white matter, specifically in parietal areas, in HD patients compared to controls. Although the global water content in the gray matter did not differ between the two groups, regional increases of brain water content in particular in parieto-temporal gray matter areas were observed in HD patients. No relevant brain hydration changes were revealed before and after hemodialysis. Whereas longer duration of dialysis vintage was associated with increased water content in parieto-temporal-occipital regions, lower intradialytic weight changes were negatively correlated with brain water content in these areas in HD patients. Worse cognitive performance on an attention task correlated with increased hydration in frontal white matter. In conclusion, long-term HD is associated with altered brain tissue water homeostasis mainly in parietal white matter regions, whereas the attentional domain in the cognitive dysfunction profile in HD could be linked to increased frontal white matter water content.

  2. Increased cerebral water content in hemodialysis patients.

    Science.gov (United States)

    Reetz, Kathrin; Abbas, Zaheer; Costa, Ana Sofia; Gras, Vincent; Tiffin-Richards, Frances; Mirzazade, Shahram; Holschbach, Bernhard; Frank, Rolf Dario; Vassiliadou, Athina; Krüger, Thilo; Eitner, Frank; Gross, Theresa; Schulz, Jörg Bernhard; Floege, Jürgen; Shah, Nadim Jon

    2015-01-01

    Little information is available on the impact of hemodialysis on cerebral water homeostasis and its distribution in chronic kidney disease. We used a neuropsychological test battery, structural magnetic resonance imaging (MRI) and a novel technique for quantitative measurement of localized water content using 3T MRI to investigate ten hemodialysis patients (HD) on a dialysis-free day and after hemodialysis (2.4±2.2 hours), and a matched healthy control group with the same time interval. Neuropsychological testing revealed mainly attentional and executive cognitive dysfunction in HD. Voxel-based-morphometry showed only marginal alterations in the right inferior medial temporal lobe white matter in HD compared to controls. Marked increases in global brain water content were found in the white matter, specifically in parietal areas, in HD patients compared to controls. Although the global water content in the gray matter did not differ between the two groups, regional increases of brain water content in particular in parieto-temporal gray matter areas were observed in HD patients. No relevant brain hydration changes were revealed before and after hemodialysis. Whereas longer duration of dialysis vintage was associated with increased water content in parieto-temporal-occipital regions, lower intradialytic weight changes were negatively correlated with brain water content in these areas in HD patients. Worse cognitive performance on an attention task correlated with increased hydration in frontal white matter. In conclusion, long-term HD is associated with altered brain tissue water homeostasis mainly in parietal white matter regions, whereas the attentional domain in the cognitive dysfunction profile in HD could be linked to increased frontal white matter water content.

  3. Information Theoretical Analysis of Identification based on Active Content Fingerprinting

    OpenAIRE

    Farhadzadeh, Farzad; Willems, Frans M. J.; Voloshinovskiy, Sviatoslav

    2014-01-01

    Content fingerprinting and digital watermarking are techniques that are used for content protection and distribution monitoring. Over the past few years, both techniques have been well studied and their shortcomings understood. Recently, a new content fingerprinting scheme called {\\em active content fingerprinting} was introduced to overcome these shortcomings. Active content fingerprinting aims to modify a content to extract robuster fingerprints than the conventional content fingerprinting....

  4. RH-TRU Waste Content Codes

    Energy Technology Data Exchange (ETDEWEB)

    Washington TRU Solutions

    2007-07-01

    The Remote-Handled Transuranic (RH-TRU) Content Codes (RH-TRUCON) document describes the inventory of RH-TRU waste within the transportation parameters specified by the Remote-Handled Transuranic Waste Authorized Methods for Payload Control (RH-TRAMPAC).1 The RH-TRAMPAC defines the allowable payload for the RH-TRU 72-B. This document is a catalog of RH-TRU 72-B authorized contents by site. A content code is defined by the following components: • A two-letter site abbreviation that designates the physical location of the generated/stored waste (e.g., ID for Idaho National Laboratory [INL]). The site-specific letter designations for each of the sites are provided in Table 1. • A three-digit code that designates the physical and chemical form of the waste (e.g., content code 317 denotes TRU Metal Waste). For RH-TRU waste to be transported in the RH-TRU 72-B, the first number of this three-digit code is “3.” The second and third numbers of the three-digit code describe the physical and chemical form of the waste. Table 2 provides a brief description of each generic code. Content codes are further defined as subcodes by an alpha trailer after the three-digit code to allow segregation of wastes that differ in one or more parameter(s). For example, the alpha trailers of the subcodes ID 322A and ID 322B may be used to differentiate between waste packaging configurations. As detailed in the RH-TRAMPAC, compliance with flammable gas limits may be demonstrated through the evaluation of compliance with either a decay heat limit or flammable gas generation rate (FGGR) limit per container specified in approved content codes. As applicable, if a container meets the watt*year criteria specified by the RH-TRAMPAC, the decay heat limits based on the dose-dependent G value may be used as specified in an approved content code. If a site implements the administrative controls outlined in the RH-TRAMPAC and Appendix 2.4 of the RH-TRU Payload Appendices, the decay heat or FGGR

  5. Description of pedagogical content knowledge (PCK) and content knowledge on Muhammadiyah Semarang University's preservice teacher

    Science.gov (United States)

    Astuti, Andari Puji; Wijayatiningsih, Testiana Deni; Azis, Abdul; Sumarti, Sri Susilogati; Barati, Dwi Anggani Linggar

    2017-12-01

    One of the competencies of teachers to be mastered under the constitution is pedagogic competence. This study aims to provide an overview of the pedagogic competence of Preservice teachers through the mastery of Pedagogical Content Knowledge (PCK) and Content knowledge (CK). The research method used is descriptive qualitative, with data retrieval technique through essay tests, questionnaire and interview. The results showed that of the five PCK indicators, only knowledge of learning strategies to teach chemistry already in high category. For Content Knowledge of preservice teachers are in the middle category for indicators of knowledge of disciplinary content, whereas knowledge that alternative frameworks for thinking about the content exist and the knowledge of the relationship between big ideas and the supporting ideas in a content area is in the fair category.

  6. Determination of soluble protein contents from RVNRL

    International Nuclear Information System (INIS)

    Wan Manshol Wan Zin; Nurulhuda Othman

    1996-01-01

    This project was carried out to determine the soluble protein contents on RVNRL film vulcanisates, with respect to the RVNRL storage time, gamma irradiation dose absorbed by the latex and the effect of different leaching time and leaching conditions. These three factors are important in the hope to determine the best possible mean of minimizing the soluble protein contents in products made from RVNRL. Within the nine months storage period employed in the study, the results show that, the longer the storage period the less the soluble protein extracted from the film samples. Gamma irradiation dose absorbed by the samples, between 5.3 kGy to 25.2 kGy seems to influence the soluble protein contents of the RVNRL films vulcanisates. The higher the dose the more was the soluble protein extracted from the film samples. At an absorbed dose of 5.3 kGy and 25.2 kGy, the soluble contents were 0. 198 mg/ml and 0.247 mg/ml respectively. At a fixed leaching temperature, the soluble proteins increases with leaching time and at a fixed leaching time, the soluble proteins increases with leaching temperature. ne highest extractable protein contents was determined at a leaching time of 10 minutes and leaching temperature of 90'C The protein analysis were done by using Modified Lowry Method

  7. Identifying the Gender Dimension in Research Content

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, D.; Lalonde, B.St.L.; Tippett, C.; Archambault, E.; Callaert, J.; Mantouvalou, K.; Arora, L.

    2016-07-01

    Globally, there is an increasing interest in integrating the gender dimension in research content (GDRC). As a first step towards monitoring progress in this area, a new indicator measuring the proportion of a country’s scientific publications integrating a gender dimension in their subject matter was developed for the European Commission’s She Figures 2015 publication. This indicator is based on a keyword-based query covering both sex-related terms (biological characteristics of both women and men) and gender-related terms (social/cultural factors of both women and men). The final GDRC dataset consisted of some 212,600 distinct publications including a gender dimension in their research content. Findings suggest that integrating a gender dimension into research content is relatively rare. Unsurprisingly, it was less common for scientific articles in the fields of agricultural sciences, engineering and technology, and natural sciences to do so, and more common in the social sciences. (Author)

  8. Quantitative measurements of autobiographical memory content.

    Directory of Open Access Journals (Sweden)

    Robert S Gardner

    Full Text Available Autobiographical memory (AM, subjective recollection of past experiences, is fundamental in everyday life. Nevertheless, characterization of the spontaneous occurrence of AM, as well as of the number and types of recollected details, remains limited. The CRAM (Cue-Recalled Autobiographical Memory test (http://cramtest.info adapts and combines the cue-word method with an assessment that collects counts of details recalled from different life periods. The SPAM (Spontaneous Probability of Autobiographical Memories protocol samples introspection during everyday activity, recording memory duration and frequency. These measures provide detailed, naturalistic accounts of AM content and frequency, quantifying essential dimensions of recollection. AM content (∼20 details/recollection decreased with the age of the episode, but less drastically than the probability of reporting remote compared to recent memories. AM retrieval was frequent (∼20/hour, each memory lasting ∼30 seconds. Testable hypotheses of the specific content retrieved in a fixed time from given life periods are presented.

  9. Development of life skills through physics content

    Science.gov (United States)

    Pivarči, Tomáš; Raganová, Janka

    2017-01-01

    The paper deals with students' life skills which the physics teacher should intentionally develop through physics content. An attention is given not only to the physics content and activities connected with it, but also to the development of responsibility, freedom, ability to make decisions, group cooperation, self-evaluation and experience of success. Three activities implemented in the seventh class of the elementary school are described in the paper. Authors describe reasons for class selection, the physics content and the used methods as well as the skills which they decided to purposely develop. They emphasize the importance of activities requiring students' inquiry-based learning and the need to change organization and philosophy of physics teaching at secondary schools. At the end of the paper authors analyze the achievement of objectives, positives as well as negatives of the implemented approaches and propose changes for a future realization.

  10. Harmonic Content of the BESSY FEL Radiation

    CERN Document Server

    Meseck, Atoosa

    2005-01-01

    BESSY proposes a linac-based cascaded High-Gain Harmonic-Generation (HGHG) free electron laser (FEL) multi-user facility. The BESSY soft X-ray FEL will consist of three undulator lines. The associated tunable lasers will cover the spectral range of 230nm to 460nm. Two to four HGHG stages reduce the seed wavelength to the desired radiation range of 1.24nm < λ < 51nm. The harmonic content of the high-intensity radiator output can be used to reduce the number of necessary HGHG stages. Moreover the higher harmonic content of the final output extends the offered spectral range and thus is of high interest for the user community. In this paper, the higher harmonic content of the final output as well as of the output of several radiators are investigated. The main parameters such as output power, pulse duration and bandwidth as well as their suitability for seeding are discussed.

  11. AVLIS documentation overview and tables of contents

    International Nuclear Information System (INIS)

    1984-01-01

    Three documents constitute the executive summary series in Data Package III: this document (Documentation Overview and Tables of Contents (E001)) plus the AVLIS Production Plant Executive Summary (E010) and the AVLIS Production Plant Overall Design Report (E020). They provide progressively greater detail on the key information and conclusions contained within the data package. The Executive Summary and Overall Design Report present summaries of each Data Package III document. They are intended to provide a global overview of AVLIS Production Plant deployment including program planning, project management, schedules, engineering design, production, operations, capital cost, and operating cost. The purpose of Overview and Tables of Contents is threefold: to briefly review AVLIS goals for Data Package III documentation, to present an overview of the contents of the data package, and to provide a useful guide to information contained in the numerous documents comprising the package

  12. TEACHING ADMINISTRATION: PROPOSAL OF THE PROGRAM CONTENT

    Directory of Open Access Journals (Sweden)

    Eduardo Ribeiro Rodrigues

    2016-08-01

    Full Text Available The National Curriculum Guidelines established by MEC (Brazilian Ministry of Education, define the specific areas of vocational training content that should be included in the curricular organization of undergraduate courses in Brazil, without suggesting or detailing which content should be offered in each area. In this sense, this study aims at proposing the course syllabus for the financial area for the undergraduate courses of Management. To achieve this goal, the curriculum matrices and the teaching plans of the financial discipline of the undergraduate courses on Management with the highest grades in ENADE were analyzed. Based on this survey, seven disciplines were elaborated with the professional qualification contents of the area, with 560 hours/class in total, distributed in the curriculum matrix, according to their goals: presentation of corporate finance and personal finance, short and long-term financial decisions, financial economic analysis, financial planning, and financial strategies.

  13. Verbal communication of semantic content in products

    DEFF Research Database (Denmark)

    Lenau, Torben Anker; Boelskifte, Per

    2005-01-01

    The purpose of the present research work is to explore how precise verbal communication can capture the semantic content of physical products. The paper presents an overview of the background and work done so far. Furthermore are ideas for future work discussed. The background includes the increa......The purpose of the present research work is to explore how precise verbal communication can capture the semantic content of physical products. The paper presents an overview of the background and work done so far. Furthermore are ideas for future work discussed. The background includes...... a number of the selected terms seem to have several interpretations causing ambiguous information. The work also suggests that more emphasis is needed in design education on training precise verbal communication concerning semantic contents in products....

  14. Data Content Protection for Virtual Libraries Heritage

    Directory of Open Access Journals (Sweden)

    Mihai DOINEA

    2016-01-01

    Full Text Available This paper presents aspects of digital content protection in virtual library systems. The legislation aspects are presented to better emphasize the need of new security mechanisms. Integrated library systems architecture is presented with focus on their main purpose, manipulating and rendering digital content to end-users. The cultural heritage stored in such systems is an important asset that needs to be protected against malicious manipulation. The characteristics of a smart virtual library, supported by an integrated library system, are analyzed and a security model is proposed for implementation, based on its particularities. The model aims to be an interface between the interactions of anonymous users with the Online Public Access Catalog of a virtual library that assures the protection of digital content. Conclusions are drawn to better support the idea of cultural persistence by the use of Information Systems.

  15. The Role of Content Aggregators In GEOValue

    Science.gov (United States)

    Wright, D. J.; Breyer, S.; Hogeweg, M.; Foust, J.; Jordan, L.; Plunkett, G.

    2016-12-01

    Data (aka content) in the form of numbers or layers, and transformed into information by way of maps, images, graphs, charts, tables, even stories, are foundational for a myriad of decision-makers. Recent advances in information technology, as well as civil remote sensing of the Earth, are rapidly allowing us to advance beyond mere static data collection and archiving, further enabling information awareness and understanding, and leading us towards knowledge and better decision making. However, such volumes, velocities, and varieties of data streams also bring with them serious dilemmas with regard to effective organization, cataloging, and easy access. This is where the role of aggregator comes in, with their provision of the necessary sustainability and reliability of information via proven, well-engineered platforms, all with the necessary interoperability and openness as guaranteed through the adoption of established standards. Information technology (IT) giants such as Google, Facebook, IBM and Apple are well known for aggregating just about every aspect of life in modern society, from our music to our mood swings. A use case of the Environmental Systems Research Institute (aka Esri) is presented as a geospatial aggregator. It has over the years, compiled, assembled and produced a carefully curated library of public content into a global "Living Atlas of the World," organized into different themes such as Earth observation, transportation, demographics, natural hazards, ecological land units, elevation, and more. Among a myriad of decision scenarios with this content to be presented is the tracking of sea ice in the Arctic, estimating potential impact to shipping lanes or coastal infrastructure, and forecasting future conditions. Esri as the main aggregator of Living Atlas content continues to welcome not only contributors who will publish new content to be included in this global Atlas, but fellow curators who will assist in reviewing, organizing, and even

  16. Determination of zinc contents in vegetables

    International Nuclear Information System (INIS)

    Salah-ud-Din; Salariya, A.M.; Yasin, M.

    1996-01-01

    Zinc content of three groups of vegetables (roots and tuber, leaves and fruits) collected from local markets was determined and are reported here. The determination was made by Atomic Absorption Spectrophotometer. The results obtained show that the zinc content of different vegetables ranged from 6.26-36.80 ppm, 8.80-70-70 ppm and 7.20-35.10 ppm for roots and tubers, fruits of vegetables respectively on dry weight basis. Generally, the values obtained in majority are not above, the maximum permissible limits. (author)

  17. Credibility Perceptions of User Generated Content

    OpenAIRE

    Murugan, S.; Nagarajan, Dr. P.S.

    2017-01-01

    Social media users generate a large volume of user generated content in various social media platforms to share their experiences in using a brand or a service. In the travel industry, the user generated content reviews are used by the prospective travellers to decide their travel plans. In the 1950’s credibility research of the media was started when television was introduced as a new media in the world dominated by newspapers. In the Social Media platforms, the credibility assessment is muc...

  18. Unsupervised Segmentation Methods of TV Contents

    Directory of Open Access Journals (Sweden)

    Elie El-Khoury

    2010-01-01

    Full Text Available We present a generic algorithm to address various temporal segmentation topics of audiovisual contents such as speaker diarization, shot, or program segmentation. Based on a GLR approach, involving the ΔBIC criterion, this algorithm requires the value of only a few parameters to produce segmentation results at a desired scale and on most typical low-level features used in the field of content-based indexing. Results obtained on various corpora are of the same quality level than the ones obtained by other dedicated and state-of-the-art methods.

  19. Determination of sulfur content in fuels

    International Nuclear Information System (INIS)

    Daucik, P.; Zidek, Z.; Kalab, P.

    1998-01-01

    The sulfur content in fuels, Diesel fuels, and in the solutions of dibutylsulfide in a white oil was determined by various methods. The results obtained by elemental analysis have shown that the method is not advisable for the determination of sulfur in fuels. A good agreement was found by comparing the results in the determination of the sulfur by Grote-Krekeler's and Hermann-Moritz's methods and by the energy-dispersive X-ray fluorescence analysis. The last method is the modern, comfortable, and timesaving method enabling the fast and precise determination of sulfur contents in the various types of samples. (authors)

  20. Design of Moisture Content Detection System

    Science.gov (United States)

    Wang, W. C.; Wang, L.

    In this paper, a method for measuring the moisture content of grain was presented based on single chip microcomputer and capacitive sensor. The working principle of measuring moisture content is introduced and a concentric cylinder type of capacitive sensor is designed, the signal processing circuits of system are described in details. System is tested in practice and discussions are made on the various factors affecting the capacitive measuring of grain moisture based on the practical experiments, experiment results showed that the system has high measuring accuracy and good controlling capacity.