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Sample records for atrp macroinitiator approach

  1. Uniform polymer-protein conjugate by aqueous AGET ATRP using protein as a macroinitiator.

    Science.gov (United States)

    Zhu, Binbin; Lu, Diannan; Ge, Jun; Liu, Zheng

    2011-05-01

    In situ aqueous activators generated by electron transfer for atom transfer radical polymerization (AGET ATRP) in air, using an enzyme as a macroinitiator, has been proposed to prepare uniform polymer-protein conjugates with improved stability under adverse conditions. In the first step, an initiator, 2-bromoisobutyryl bromide (BIB), was grafted onto the protein surface by reaction with the amino groups. The second step was in situ AGET ATRP polymerization in air using CuBr(2)/1,1,4,7,7-pentamethyldiethylenetriamine as a catalyst and ascorbic acid as a reducing agent. The effectiveness of this method has been demonstrated using horseradish peroxidase (HRP) as a model protein and acrylamide as the monomer, which yielded HRP-polyacrylamide conjugate with a mean particle size of about 20-30 nm. The grafting of BIB onto HRP and the subsequent polymerization yielding a polyacrylamide chain were confirmed by nuclear magnetic resonance and matrix-assisted laser desorption ionization time-of-flight spectrometry analysis. The size of the conjugate was shown to be a function of monomer loading and reaction time. The HRP conjugates yielded essentially retained the catalytic behavior of HRP in free form, as shown by K(m) and V(max) values, but exhibited significantly enhanced thermal stability against high temperature and trypsin digestion. The use of protein as the macroinitiator prevented the formation of copolymer and thus facilitated purification of the protein conjugate. The uniform size indicates a well-defined composition of protein and polymer, which is essential for applications that request a precise control of the dosage of enzyme activity. Copyright © 2011. Published by Elsevier Ltd.

  2. Fluorinated bio-acceptable polymers via an ATRP macroinitiator approach

    DEFF Research Database (Denmark)

    Hansen, Natanya Majbritt Louie; Haddletion, D.M.; Hvilsted, Søren

    2007-01-01

    -methanimine with the methacrylates MMA and PEGMA and 1,1,4,7,10,10-hexamethyltriethylene tetramine (HMTETA) with MEA. In all cases the use of the fluorinated initiator results in a lower apparent rate of propagation (k(p)(aPP)) as compared with the more conventional and nonfluorinated initiator, ethyl 2-bromoisobutyrate...

  3. AGET ATRP of acrylonitrile with ionic liquids as reaction medium without any additional ligand

    Energy Technology Data Exchange (ETDEWEB)

    Chen Hou, E-mail: lduchenhou@hotmail.com [School of Chemistry and Materials Science, Ludong University, Yantai 264025 (China); Liang Ying; Liu Delong; Tan Zhi; Zhang Shaohong; Zheng Meiling; Qu Rongjun [School of Chemistry and Materials Science, Ludong University, Yantai 264025 (China)

    2010-05-10

    Atom transfer radical polymerization using activators generated by electron transfer (AGET ATRP) of acrylonitrile (AN) was carried out for the first time in 1-methylimidazolium acetate ([mim][AT]), 1-methylimidazolium propionate([mim][PT]), and 1-methylimidazolium butyrate ([mim][BT]), respectively. The polymerization was approached by using ascorbic acid (VC) as a reducing agent, ethyl 2-bromoisobutyrate (EBiB) as initiator, only FeBr{sub 3} as catalyst without any additional ligand. Kinetic studies showed that both AGET ATRP of AN in the absence of oxygen and in the presence of air proceeded in a well-controlled manner. Under the same conditions, the polymerization in the presence of air provided rather slower reaction rate and showed better control of molecular weight and its distribution than in the absence of oxygen. The sequence of the apparent polymerization rate constants of AGET ATRP of AN in three ionic liquids was k{sub app}([mim][AT]) > k{sub app}([mim][PT]) > k{sub app}([mim][BT]). The living nature of the polymerization was confirmed by chain end analysis and block copolymerization of methyl methacrylate with polyacrylonitrile as macroinitiator. All the three ionic liquids and FeBr{sub 3} could be recycled and reused and had no effect on the living nature of polymerization.

  4. Synthesis of novel glycopolymer brushes via a combination of RAFT-mediated polymerisation and ATRP

    Directory of Open Access Journals (Sweden)

    Eric T.A. van den Dungen

    2011-03-01

    Full Text Available Glycopolymers (synthetic sugar-containing polymers have become increasingly attractive to polymer chemists because of their role as biomimetic analogues and their potential for commercial applications. Glycopolymers of different structures confer high hydrophilicity and water solubility and can therefore be used for specialised applications, such as artificial materials for a number of biological, pharmaceutical and biomedical uses. The synthesis and characterisation of a series of novel glycopolymer brushes, namely poly(2-(2-bromoisobutyryloxy ethyl methacrylate-g-poly(methyl 6-O-methacryloyl-α-D-glucoside (P(BIEM-g-P(6-O-MMAGIc, poly(2-(2-bromoisobutyryloxy ethyl methacrylate-co-methyl methacrylate-g-poly(methyl 6-O-methacryloyl-α-D-glucoside P(BIEM-co-MMA-g-P(6-O-MMAGIc, poly(2-(2-bromoisobutyryloxy ethyl methacrylate-b-methyl methacrylate-g-poly(methyl 6-O-methacryloyl-α-D-glucoside P(BIEM-b-MMA-g-P(6-O-MMAGIc and poly(4-vinylbenzyl chloride-alt-maleic anhydride-g-poly(methyl 6-O-methacryloyl-α-D-glucoside (P(Sd-alt-MAnh-g-P(6-O-MMAGIc are described in this paper. Reversible addition-fragmentation chain transfer (RAFT-mediated polymerisation was used to synthesise four well-defined atom transfer radical polymerisation (ATRP macroinitiators (the backbone of the glycopolymer brushes. These ATRP macroinitiators were subsequently used in the ‘grafting from’ approach (in which side chains are grown from the backbone to prepare high molar mass and low polydispersity index glycopolymer brushes with different grafting densities along the backbone. The number average molar mass of the glycopolymer brushes was determined using size exclusion chromatography with a multi-angle laser light

  5. Synthesis and ATRP of novel fluorinated aromatic monomer with pendant sulfonate group

    DEFF Research Database (Denmark)

    Dimitrov, Ivaylo; Jankova Atanasova, Katja; Hvilsted, Søren

    2013-01-01

    Novel, fluorinated monomer with pendant sulfonate group was synthesized utilizing a two-step derivatization of 2,3,4,5,6-pentafluorostyrene (FS). The first step was a nucleophilic substitution of the fluorine atom in para position by hydroxyl group followed by sulfopropylation. The monomer...... was polymerized under aqueous ATRP conditions to yield phenyl-fluorinated aromatic homopolymer bearing pendant sulfonates on each repeating unit. Furthermore, this polymer was used as macroinitiator for the ATRP of poly(ethylene glycol) methacrylate. The polymers were characterized by 1H NMR, SEC and FTIR...

  6. Star polymers by ATRP of styrene and acrylates employing multifunctional initiators

    DEFF Research Database (Denmark)

    Jankova, Katja Atanassova; Bednarek, Melania; Hvilsted, Søren

    2005-01-01

    Multifunctional initiators for atom transfer radical polymerization (ATRP) are prepared by converting ditrimethylolpropane with four hydroxyl groups, dipentaerythritol with six hydroxyl groups, and poly(3-ethyl-3-hydroxymethyl-oxetane) with similar to 11 hydroxyl groups to the corresponding 2......-bromoisobutyrates or 2-bromopropionates as obtained by reaction with acid bromides. Star polystyrene (PS) is produced by using these macroinitiators and neat styrene in a controlled manner by ATRP at 110 degrees C, employing the catalytic system CuBr and bipyridine. M. up to 51,000 associated with narrow molecular...

  7. SYNTHESIS OF CELLULOSE-GRAFT-POLY(METHYL METHACRYLATE) VIA HOMOGENEOUS ATRP

    OpenAIRE

    Ting-Ting Xin; Tongqi Yuan; Shu Xiao; Jing He

    2011-01-01

    Cellulose-graft-poly(methylmethacrylate) (cellulose-g-PMMA) copolymers were prepared by homogeneous atom transfer radical polymerization (ATRP) under mild conditions, in an attempt to develop an efficient way to modify the surface of cellulose. A cellulose macro-initiator was successfully synthesized by direct homogeneous acylation of cellulose with 2-bromopropionyl bromide in a room temperature ionic liquid (RTIL), 1-allyl-3-methylimidazolium chloride ([AMIM]Cl). Copolymers were obtained via...

  8. Synthesis and characterization of a novel water-soluble cationic diblock copolymer with star conformation by ATRP

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shuzhao [Department of Chemical Engineering, University of New Brunswick, Fredericton, NB E3B 5A3 (Canada); School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Xiao, Miaomiao [Department of Chemical Engineering, University of New Brunswick, Fredericton, NB E3B 5A3 (Canada); Zheng, Anna [School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Xiao, Huining, E-mail: hxiao@unb.ca [Department of Chemical Engineering, University of New Brunswick, Fredericton, NB E3B 5A3 (Canada)

    2014-10-01

    A water-soluble cationic diblock copolymer, CD-PAM-b-PMeDMA, was synthesized through atom transfer radical polymerization (ATRP) from a β-cyclodextrin (CD) macroinitiator with 10-active sites (10Br-β-CD). In order to reduce the cytotoxicity of the CD-PAM-b-PMeDMA, biocompatible polyacrylamide (PAM) was first introduced onto the surface of β-CD as a scaffold structure by ATRP using the 10Br-β-CD as a macroinitiator. The reaction conditions of AM were explored and optimized. The ATRP of [2-(methacryloyloxy)ethyl] trimethyl ammonium chloride (MeDMA) was also performed to synthesize the second cationic block using the resulting CD-PAM as a macroinitiator. The resulting diblock copolymer shows an increased hydrodynamic radius in aqueous solution with a pretty low concentration compared with β-CD. In addition, it appears a near-uniform coniform after being deposited on mica ascribed to the presence of an asymmetric 10-arm structure. - Highlights: • A 10-arm diblock polymer was prepared by ATRP for the potential use as a non-viral gene delivery. • PAM was first synthesized in a controlled manner considering its biocompatibility. • The hydrodynamic radius of the copolymer in aqueous solution increase to 130 nm from 7.5 nm of CD. • The copolymer appears coniform after deposited on mica surface due to the charge attraction.

  9. Synthesis and characterization of a novel water-soluble cationic diblock copolymer with star conformation by ATRP.

    Science.gov (United States)

    Li, Shuzhao; Xiao, Miaomiao; Zheng, Anna; Xiao, Huining

    2014-10-01

    A water-soluble cationic diblock copolymer, CD-PAM-b-PMeDMA, was synthesized through atom transfer radical polymerization (ATRP) from a β-cyclodextrin (CD) macroinitiator with 10-active sites (10Br-β-CD). In order to reduce the cytotoxicity of the CD-PAM-b-PMeDMA, biocompatible polyacrylamide (PAM) was first introduced onto the surface of β-CD as a scaffold structure by ATRP using the 10Br-β-CD as a macroinitiator. The reaction conditions of AM were explored and optimized. The ATRP of [2-(methacryloyloxy)ethyl] trimethyl ammonium chloride (MeDMA) was also performed to synthesize the second cationic block using the resulting CD-PAM as a macroinitiator. The resulting diblock copolymer shows an increased hydrodynamic radius in aqueous solution with a pretty low concentration compared with β-CD. In addition, it appears a near-uniform coniform after being deposited on mica ascribed to the presence of an asymmetric 10-arm structure. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. New highly fluorinated styrene-based materials with low surface energy prepared by ATRP

    DEFF Research Database (Denmark)

    Borkar, Sachin; Jankova Atanasova, Katja; Siesler, Heinz W

    2004-01-01

    2,3,5,6-Tetrafluoro-4-(2,2,3,3,3-pentafluoropropoxy)styrene (TF(F-5)S) and 2,3,5,6-tetrafluoro-4-(2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctaoxy)styrene (TF(F,5)S) are prepared by nucleophilic substitution of 2,3,4,5,6-pentafluorostyrene. The neat monomers are subjected to atom transfer...... radical polymerization (ATRP) at 110 degreesC to high conversions in relatively short times, 10-120 min; TF(F-5)S is additionally polymerized at 70 and 90 degreesC. Block copolymers with styrene are prepared by the macroinitiator approach. All polymers, in the number-average molecular weight range from...... than 10 mol %. The fluorinated side chains of P(TF(F-5)S) and P(TF(F-15)S) enrich the surface of thin films, which results in an advancing water contact angle of 117degrees and 122degrees, respectively. Both XPS analyses and contact angle measurements strongly imply that the fluorinated parts...

  11. Expanded corn starch as a versatile material in atom transfer radical polymerization (ATRP) of styrene and methyl methacrylate.

    Science.gov (United States)

    Bansal, Ankushi; Kumar, Arvind; Latha, Patnam Padma; Ray, Siddharth Sankar; Chatterjee, Alok Kumar

    2015-10-05

    Polymerization of styrene (St) and methyl methacrylate (MMA) was performed by surface initiated (SI) and activator generated by electron transfer (AGET) systems of atom transfer radical polymerization (ATRP) using renewable expanded corn starch (ECS) as a support. This prepared ECS is found to have V type crystallinity with 50 m(2)g(-1) surface area (<1m(2)g(-1) for corn starch (CS)) and average pore volume of 0.43 cm(3)g(-1) (<0.1cm(3)g(-1) for CS). In SI-ATRP, hydroxyl groups on ECS were converted into macro-initiator by replacing with 2-bromoisobutyryl bromide (BIBB) with a 0.06 degree of substitution determined from NMR. In AGET-ATRP, CuBr2/ligand complex get adsorbed on ECS (Cu(II)/ECS=10 wt.%) to catalyze the polymerization. Synthesized PS/PMMA was characterized by SEM, FT-IR, (1)H NMR. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Synthesis by ATRP of poly(ethylene-co-butylene)-block-polystyrene, poly(ethylene-co-butylene)-block-poly(4-acetoxystyrene) and its hydrolysis product poly(ethylene-co-butylene)-block-poly(hydroxystyrene)

    DEFF Research Database (Denmark)

    Jankova, Katja; Kops, Jørgen; Chen, Xianyi

    1999-01-01

    Diblock copolymers of poly(ethylene-co-butylene) and polystyrene or poly(4-acetoxystyrene) are synthesized by atom transfer radical polymerization (ATRP) using a 2-bromopropionic ester macroinitiator prepared from commercial monohydroxyl functional narrow dispersity hydrogenated polybutadiene...... (Kraton Liquid Polymer, L-1203). ATRP carried out in bulk and in xylene solution with cuprous bromide and two different complexing agents 2,2'-bipyridine (bipy) and 1,1,4,7,10,10-hexamethyltriethylenetetraamine (HMTETA) yielded well-defined diblock copolymers with polydispersities around 1,3. The diblock...... copolymer with poly(4-acetoxystyrene) was hydrolyzed to the corresponding poly(4-hydroxystyrene) sequence....

  13. Surface Initiated Polymerizations via e-ATRP in Pure Water

    Directory of Open Access Journals (Sweden)

    Seyed Schwan Hosseiny

    2013-10-01

    Full Text Available Here we describe the combined process of surface modification with electrochemical atom transfer radical polymerization (e-ATRP initiated from the surface of a modified gold-electrode in a pure aqueous solution without any additional supporting electrolyte. This approach allows for a very controlled growth of the polymer chains leading towards a steady increase in film thickness. Electrochemical quartz crystal microbalance displayed a highly regular increase in surface confined mass only after the addition of the pre-copper catalyst which is reduced in situ and transformed into the catalyst. Even after isolation and washing of the modified electrode surface, reinitiation was achieved with retention of the controlled electrochemical ATRP reaction. This reinitiation after isolation proves the livingness of the polymerization. This approach has interesting potential for smart thin film materials and offers also the possibility of post-modification via additional electrochemical induced reactions.

  14. Synthesis of PMMA-b-PU-b-PMMA tri-block copolymers through ARGET ATRP in the presence of air

    Directory of Open Access Journals (Sweden)

    P. Krol

    2013-03-01

    Full Text Available ARGET (activators regenerated by electron transfer ATRP (atom transfer radical polymerization has been successfully performed (in flasks fitted with rubber septa without the need for use of Schlenk line in the presence of limited amount of air and with a very small (370 ppm amount of copper catalyst together with an appropriate reducing agent Cu(0. Novelty of this work is that the poly(methyl methacrylate-block-polyurethane-block-poly(methyl methacrylate triblock copolymers were synthesized for the first time through ARGET ATRP, by using tertiary bromine-terminated polyurethane as a macroinitiator (MBP-PU-MBP, CuBr2 or CuCl2 as a catalyst and N,N,N',N",N"-pentamethyldiethylenetriamine (PMDETA or 2,2'-bipyridine (Bpy as a complexing agent. As the polymerization time increases, both the monomer conversion and ln([M]0/[M] increased and the molecular weight of copolymer increases linearly with increasing conversion. Theoretical number-average molecular weight (Mn, th of the tri-block copolymers was found to be comparable with number-average molecular weight determined by GPC analyses (Mn, GPC. These results indicate that the formation of the tri-block copolymers was through atom transfer radical polymerization mechanism. 1H and 13C NMR spectral methods were employed to confirm chemical structures of synthesized macroinitiator and tri-block copolymers. Mole percentage of PMMA in the tri-block copolymers was calculated using 1H NMR spectroscopy and was found to be comparable with the GPC results. Additionally, the studies of surface properties (confocal microscopy and SFE of tri-block copolymer coatings confirmed the presence of MMA segments.

  15. Organophilic Boehmite nanoparticles by ATRP methacrylates polymerization: synthesis, characterization and dispersion in polypropylene.

    Science.gov (United States)

    Coiai, Serena; Passaglia, Elisa; Augier, Sylvain; Narducci, Piero; Ciardelli, Francesco

    2008-04-01

    Boehmite nanoparticles covered with a polymer shell enhancing the organophilicity of the surface were prepared by physical adsorption of a polyelectrolyte atom transfer radical polymerization (ATRP) macroinitiator followed by graft-polymerization of methyl methacrylate or 2-hydroxyethyl methacrylate. The presence of polymer chains adsorbed/grafted on the Boehmite was confirmed by attenuated total reflection infrared (ATR-IR) spectroscopy and by thermo-gravimetric analysis (TGA), which showed a significant amount of polymer covering the particles. The methodology of polymerization and the kinetics suggested the possibility to modulate the amount, type and thickness of grafted polymer shell. These organic-inorganic hybrid materials were melt compounded in a Brabender mixer with isotactic polypropylene in the presence of functionalized polypropylene. The dispersion degree of Boehmite nanoparticles in the polypropylene matrix as well as their reinforcing effect were studied by morphology characterization [scanning electron microscopy (SEM) and X-ray diffraction (XRD)], whereas thermal and thermo-mechanical properties were assessed by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA).

  16. ATRP in the design of functional materials for biomedical applications.

    Science.gov (United States)

    Siegwart, Daniel J; Oh, Jung Kwon; Matyjaszewski, Krzysztof

    2012-01-01

    Atom Transfer Radical Polymerization (ATRP) is an effective technique for the design and preparation of multifunctional, nanostructured materials for a variety of applications in biology and medicine. ATRP enables precise control over macromolecular structure, order, and functionality, which are important considerations for emerging biomedical designs. This article reviews recent advances in the preparation of polymer-based nanomaterials using ATRP, including polymer bioconjugates, block copolymer-based drug delivery systems, cross-linked microgels/nanogels, diagnostic and imaging platforms, tissue engineering hydrogels, and degradable polymers. It is envisioned that precise engineering at the molecular level will translate to tailored macroscopic physical properties, thus enabling control of the key elements for realized biomedical applications.

  17. Polymers and block copolymers of fluorostyrenes by ATRP

    DEFF Research Database (Denmark)

    Hvilsted, Søren; Borkar, Sachin; Abildgaard, Lillian

    2002-01-01

    Fully or partly fluorinated polymers have many desirable and intriguing properties. In the framework of a larger program on design and control of new functional block copolymers we recently employed the Atom Transfer Radical Polymerization (ATRP) protocol on 2,3,4,5,6-pentafluorostyrene (FS). We...... materials based on 2,3,5,6-tetrafiuoro-4-methoxy-styrene (TFMS). TFMS homopolymers as well as diblock copolymers with FS are produced by ATRP. Both types of novel polymers were subsequently demethylated and different side chains introduced on the resulting hydroxy sites....

  18. POLYMERIZATION IN SOLUTION AS A WAY TO OPTIMIZE THE SYNTHESIS OF BETA-DIKETONATE MACROINITIATORS BASED ON POLYMETHYLMETHACRYLATE

    Directory of Open Access Journals (Sweden)

    O. V. Shevchenko

    2016-10-01

    Full Text Available The polymerization of methyl methacrylate initiated by Co (II 5-methyl-5-hexene-2,4-dionate (MHD-Co solution in dimethylformamide, methyl ethyl ketone and toluene has been studied.  It is shown that polymerization does not take place in the solution of dimethylformamide due to the formation of inactive complexes «β-diketonate-solvent». Maximal polymerization rate has been observed in methyl ethyl ketone. The polymerization rate increases with decreasing of initiator concentration due to the MHD-Co inhibitory effect at high concentrations of chelate. The optimal concentration range of MHD-Co for polymerization initiation of methyl methacrylate in methyl ethyl ketone is 1,0-2,5×10-3 mol/l. The differences are noted in the behavior of the MHD-Co which chelate ring is conjugated with the double bond of the ligand, in comparison to cobalt 3-allylpentane-2,4-dionate where such conjugation is absent. The synthesized products are soluble in the monomers, they have a large number of metal chelate groups and can be used as macroinitiators in the preparation of branched and graft polymers. The total molecular weight of the grafted chains is much longer than the main chain.

  19. From Novel Block-Like Copolymers to Reactive Nanoparticles: ATRP and ``Click'' Chemistry as Synthetic Tools

    Science.gov (United States)

    van Camp, Wim; Dervaux, Bart; Lammens, Mieke; van Renterghem, Lieven; Prez, Filip Du

    In this chapter, we report on the synthesis and characterization of well-defined amphiphilic block copolymers, ‘block-like’ copolymers and star copolymers composed of poly(isobornyl acrylate) (PiBA) and poly(acrylic acid) (PAA) by ATRP. As PiBA polymers exhibit interesting physical characteristics, we report first a detailed study of the homopolymerization of iBA. The precursor monomers 1-ethoxyethyl acrylate as well as tert-butyl acrylate have been used to synthesize the precursor polymers for the PiBA-co-PAA block copolymers. Furthermore, a combination of ATRP and ‘click’ chemistry was used to prepare block and graft copolymers using a modular approach. The PiBA-PAA block and ‘block-like’ copolymers were investigated as pigment stabilizers for aqueous pigment dispersions. In the second part of the research, well-defined PiBA star copolymers were prepared, and reactive nanoparticles were obtained by end group modification of the PiBA star polymers with reactive moieties. Finally, the control of the visco-elastic properties by the incorporation of these nanoparticles in an acrylate polymer matrix was investigated.

  20. Hemocompatible surface of electrospun nanofibrous scaffolds by ATRP modification

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Wenjie [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Feng, Yakai, E-mail: yakaifeng@hotmail.com [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Key Laboratory of Systems Bioengineering of Ministry of Education, Tianjin University, Tianjin 300072 (China); Tianjin University-Helmholtz-Zentrum Geesthacht, Joint Laboratory for Biomaterials and Regenerative Medicine, Weijin Road 92, 300072 Tianjin (China); Wang, Heyun [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832002 (China); Yang, Dazhi [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); An, Bo [Department of Orthopedics, Affiliated Hospital of Logistics University of Chinese People' s Armed Police Force, Tianjin 300162 (China); Zhang, Wencheng [Department of Physiology and Pathophysiology, Logistics University of Chinese People' s Armed Police Force, Tianjin 300162 (China); Khan, Musammir [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Guo, Jintang [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Tianjin University-Helmholtz-Zentrum Geesthacht, Joint Laboratory for Biomaterials and Regenerative Medicine, Weijin Road 92, 300072 Tianjin (China)

    2013-10-15

    The electrospun scaffolds are potential application in vascular tissue engineering since they can mimic the nano-sized dimension of natural extracellular matrix (ECM). We prepared a fibrous scaffold from polycarbonateurethane (PCU) by electrospinning technology. In order to improve the hydrophilicity and hemocompatibility of the fibrous scaffold, poly(ethylene glycol) methacrylate (PEGMA) was grafted onto the fiber surface by surface-initiated atom transfer radical polymerization (SI-ATRP) method. Although SI-ATRP has been developed and used for surface modification for many years, there are only few studies about the modification of electrospun fiber by this method. The modified fibrous scaffolds were characterized by SEM, Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS). The scaffold morphology showed no significant difference when PEGMA was grafted onto the scaffold surface. Based on the water contact angle measurement, the surface hydrophilicity of the scaffold surface was improved significantly after grafting hydrophilic PEGMA (P = 0.0012). The modified surface showed effective resistance for platelet adhesion compared with the unmodified surface. Activated partial thromboplastin time (APTT) of the PCU-g-PEGMA scaffold was much longer than that of the unmodified PCU scaffold. The cyto-compatibility of electrospun nanofibrous scaffolds was tested by human umbilical vein endothelial cells (HUVECs). The images of 7-day cultured cells on the scaffold surface were observed by SEM. The modified scaffolds showed high tendency to induce cell adhesion. Moreover, the cells reached out pseudopodia along the fibrous direction and formed a continuous monolayer. Hemolysis test showed that the grafted chains of PEGMA reduced blood coagulation. These results indicated that the modified electrospun nanofibrous scaffolds were potential application as artificial blood vessels. Highlights: • Electrospun nanofibrous scaffolds were successfully

  1. Functionalization of PEDOT by Click Chemistry and ATRP

    DEFF Research Database (Denmark)

    Hoffmann, Christian; Daugaard, Anders Egede

    Poly(3,4‐ethylenedioxythiophene) (PEDOT) is a conductive polymer which has received increasing attention and many developments have been investigated. PEDOT has been applied in many different areas such as biosensors or polymer solar cells. This work presents a modification of PEDOT films through...... Click Chemistry with alkynes followed by activator regenerated by electron transfer (ARGET) atom transfer radical polymerization (ATRP) to develop PEDOT films with anti‐fouling properties through application of a model system based on a crosslinked surface of polystyrene PS‐N3....

  2. Fentanyl Initiated Polymers Prepared by ATRP for Targeted Delivery.

    Science.gov (United States)

    Cohen-Karni, Devora; Kovaliov, Marina; Li, Shaohua; Jaffee, Stephen; Tomycz, Nestor D; Averick, Saadyah

    2017-04-19

    The targeted delivery of polymers to neurons is a challenging yet important goal for polymer based drug delivery. We prepared a fentanyl based atom transfer radical polymerization (ATRP) initiator to target the Mu opioid receptor (MOR) for neuronal targeting. We incorporated our recently discovered rigid acrylate linking group into the initiator to retain a high degree of binding to the MOR and grafted random or block copolymers of poly(oligo(ethylene oxide) methacrylate)-block-(glycidyl methacrylate). Trifluoroethanol promoted amine ring opening of the glycidyl methacrylate was used for post-polymerization modification of the fentanyl initiated polymers to attach a near-infrared fluorescent dye (ADS790WS) or to build a targeted siRNA delivery system via modification with secondary amines. We examined the biocompatibility, cellular internalization, and siRNA binding properties of our polymer library in a green fluorescent protein expressing SY SH5Y neuroblastoma cell-line.

  3. Iron-Mediated ICAR ATRP of Styrene and Methyl Methacrylate in the Absence of Thermal Radical Initiator.

    Science.gov (United States)

    Zhang, Lifen; Miao, Jie; Cheng, Zhenping; Zhu, Xiulin

    2010-02-02

    Initiators for continuous activator regeneration in atom transfer radical polymerization (ICAR ATRP) is a new technique for conducting ATRP. ICAR ATRP has many strong advantages over normal ATRP, such as forming the reductive transition metal species in situ using oxidatively stable transition metal species and a lower amount of metal catalyst in comparison with the normal ATRP system. In this work, the iron-mediated ICAR ATRP of styrene and methyl methacrylate are reported for the first time using oxidatively stable FeCl(3)  · 6H(2) O as the catalyst in the absence of any thermal radical initiator. The kinetics of the polymerizations and effect of different polymerization conditions are studied. It is found that the polymerization of styrene can be conducted well even if the amount of iron(III) is as low as 50 ppm. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. The Effect of Covalently-Attached ATRP-Synthesized Polymers on Membrane Stability and Cytoprotection in Human Erythrocytes

    National Research Council Canada - National Science Library

    Clafshenkel, William P; Murata, Hironobu; Andersen, Jill; Creeger, Yehuda; Koepsel, Richard R; Russell, Alan J

    2016-01-01

    ... that otherwise facilitate their premature clearance from circulation. Surface modification of erythrocytes using rationally designed polymers, synthesized via atom-transfer radical polymerization (ATRP...

  5. New Star-Branched Poly(acrylonitrile) Architectures : ATRP Synthesis and Solution Properties

    NARCIS (Netherlands)

    Pitto, Valentina; Voit, Brigitte I.; Loontjens, Ton J.A.; Benthem, Rolf A.T.M. van

    2004-01-01

    Atom transfer radical polymerization (ATRP) has been chosen as ‘‘living’’/controlled free radical polymerization system to synthesize a number of novel poly(acrylonitrile) (PAN) architectures. The reaction conditions for the synthesis of linear samples with control over molar mass and molar mass

  6. Cellulose-based graft copolymers prepared by simplified electrochemically mediated ATRP

    Directory of Open Access Journals (Sweden)

    P. Chmielarz

    2017-02-01

    Full Text Available Brush-shaped block copolymer with a dual hydrophilic poly(acrylic acid-block-poly(oligo(ethylene glycol acrylate (PAA-b-POEGA arms was synthesized for the first time via a simplified electrochemically mediated ATRP (seATRP under both constant potential electrolysis and constant current electrolysis conditions, utilizing only 30 ppm of catalyst complex. The polymerization conditions were optimized to provide fast reactions while employing low catalyst concentrations and preparation of cellulose-based brush-like copolymers with narrow molecular weight distributions. The results from proton nuclear magnetic resonance (1H NMR spectral studies support the formation of cellulose-based graft (copolymers. It is expected that these new polymer brushes may find application as pH- and thermo-sensitive drug delivery systems.

  7. Recent Progress on Transition Metal Catalyst Separation and Recycling in ATRP.

    Science.gov (United States)

    Ding, Mingqiang; Jiang, Xiaowu; Zhang, Lifen; Cheng, Zhenping; Zhu, Xiulin

    2015-10-01

    Atom transfer radical polymerization (ATRP) is a versatile and robust tool to synthesize a wide spectrum of monomers with various designable structures. However, it usually needs large amounts of transition metal as the catalyst to mediate the equilibrium between the dormant and propagating species. Unfortunately, the catalyst residue may contaminate or color the resultant polymers, which limits its application, especially in biomedical and electronic materials. How to efficiently and economically remove or reduce the catalyst residue from its products is a challenging and encouraging task. Herein, recent advances in catalyst separation and recycling are highlighted with a focus on (1) highly active ppm level transition metal or metal free catalyzed ATRP; (2) post-purification method; (3) various soluble, insoluble, immobilized/soluble, and reversible supported catalyst systems; and (4) liquid-liquid biphasic catalyzed systems, especially thermo-regulated catalysis systems. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Synthesis of ABCBA penta stereoblock polylactide copolymers by two-step ring-opening polymerization of L- and D-lactides with poly(3-methyl-1,5-pentylene succinate) as macroinitiator (C): development of flexible stereocomplexed polylactide materials.

    Science.gov (United States)

    Hirata, Masayuki; Masutani, Kazunari; Kimura, Yoshiharu

    2013-07-08

    BCB triblock copolymers consisting of poly-L-lactide (PLLA: B) and poly(3-methy-1,5-pentylene succinate) (SA/MPD: C) were first synthesized by ring-opening polymerization (ROP) of L-lactide by using a dihydroxyl-terminated SA/MPD (Mn≈20k) and tin octoate as the macroinitiator and catalyst, respectively. The telechelic dihydroxyl-terminated SA/MPD was readily synthesized by the controlled melt-polycondensation of succinic acid and 3-methyl-1,5-pentandiol (MPD). The resultant triblock copolymers, dihydroxyl-terminated, were subsequently utilized as the macroinitiators in the second-step ROP of D-lactide to obtain ABCBA penta-block copolymers (penta-sb-PLA) consisting of poly-D-lactide (PDLA), PLLA, and SA/MPD as the A, B, and C blocks, respectively. The weight-average molecular weights of the resultant penta-sb-PLAs became higher than 150 kDa. The cast films of these penta-sb-PLAs exhibited flexible nature due to the presence of the SA/MPD soft block as well as excellent heat-stability owing to the easy stereocomplex formation of the neighboring enantiomeric PLLA and PDLA blocks.

  9. Use of Yb-based catalyst for AGET ATRP of acrylonitrile to simultaneously control molecular mass distribution and tacticity

    Energy Technology Data Exchange (ETDEWEB)

    Ma Jing; Chen Hou, E-mail: lduchenhou@hotmail.com; Zhang Min; Wang Chunhua; Zhang Ying; Qu Rongjun

    2012-08-01

    Yb-based catalyst was used for the first time for atom transfer radical polymerization using activators generated by electron transfer (AGET ATRP) of acrylonitrile (AN) with 2-bromopropionitrile (BPN) as initiator, 2, 2 Prime -bipyridine (bipy) as ligand, and tisn(II) bis(2-ethylhexanoate) (Sn(EH){sub 2}) as reducing agent in the presence of air. With respect to AGET ATRP of AN catalyzed by CuBr{sub 2}, an evident increase of polymer tacticity was observed for AGET ATRP of AN. The increase of syndiotacticity became more and more pronounced than the increase of isotacticity of polyacrylonitrile (PAN) along with YbBr{sub 3} content. The block copolymer PAN-b-PMMA with molecular weight at 60,000 and polydispersity at 1.36 was successfully prepared. - Graphical abstract: Yb-based catalyst was used for the first time for AGET ATRP of AN with BPN as the initiator, bipy as the ligand, and Sn(EH){sub 2} as the reducing agent in the presence of air. With respect to AGET ATRP with CuBr{sub 2} as catalyst, an obvious increase of polymer tacticity was observed for AGET ATRP of AN. The increase of syndiotacticity became more and more pronounced than the increase of isotacticity of polyacrylonitrile (PAN) along with YbBr{sub 3} content. The block copolymer PAN-b-PMMA with molecular weight at 60000 and polydispersity at 1.36 was successfully prepared. Highlights: Black-Right-Pointing-Pointer Yb-based catalyst was used for the first time for AGET ATRP of AN. Black-Right-Pointing-Pointer The reaction simultaneously controls polydispersity and tacticity of PAN. Black-Right-Pointing-Pointer Well-defined block copolymer PAN-b-PMMA was successfully prepared.

  10. Controlled release of cortisone drugs from block copolymers synthetized by ATRP

    Energy Technology Data Exchange (ETDEWEB)

    Valenti, G.; La Carta, S.; Rapisarda, M.; Carbone, D.; Recca, G.; Rizzarelli, P., E-mail: paola.rizzarelli@cnr.it [Istituto per i Polimeri, Compositi e Biomateriali, Consiglio Nazionale delle Ricerche Via P. Gaifami 18, 95129 Catania (Italy); Mazzotti, G.; Giorgini, L. [Dipartimento di Chimica Industriale «Toso Montanari», Università di Bologna Via Risorgimento 4, 40136 Bologna (Italy); Perna, S. [ST Microelectronics Srl, Stradale Primosole, 50–95121 Catania (Italy); Di Gesù, R. [Merck Serono S.p.A., Via L. Einaudi, 11–00012 Guidonia Montecelio, Rome (Italy)

    2016-05-18

    Diseases affecting posterior eye segment, like macular edema, infection and neovascularization, may cause visual impairment. Traditional treatments, such as steroidal-drugs intravitreal injections, involve chronic course of therapy usually over a period of years. Moreover, they can require frequent administrations of drug in order to have an adequately disease control. This dramatically reduce patient’s compliance. Efforts have been made to develop implantable devices that offer an alternative therapeutic approach to bypass many challenges of conventional type of therapy. Implantable drug delivery systems (DDS) have been developed to optimize therapeutic properties of drugs and ensure their slow release in the specific site. Polymeric materials can play an essential role in modulating drug delivery and their use in such field has become indispensable. During last decades, acrylic polymers have obtained growing interest. Biocompatibility and chemical properties make them extremely versatile, allowing their use in many field such as biomedical. In particular, block methacrylate copolymer with a balance of hydrophilic and hydrophobic properties can be suitable for prolonged DDS in biomedical devices. In this work, we focused on the realization of a system for controlled and long term release of betamethasone 17,21-dipropionate (BDP), a cortisone drug, from methacrylic block copolymers, to be tested in the treatment of the posterior eye’s diseases. Different series of methyl methacrylate/hydroxyethyl methacrylate (MMA/HEMA) block and random copolymers, with different monomer compositions (10–60% HEMA), were synthetized by Atom Transfer Radical Polymerization (ATRP) to find the best hydrophilic/hydrophobic ratio, able to ensure optimal kinetic release. Copolymer samples were characterized by NMR spectroscopy ({sup 1}H-NMR, {sup 13}C-NMR, CosY), SEC, TGA and DSC. Monitoring of drug release from films loaded with BDP was carried out by HPLC analysis. Evaluation of

  11. Controlled release of cortisone drugs from block copolymers synthetized by ATRP

    Science.gov (United States)

    Valenti, G.; La Carta, S.; Mazzotti, G.; Rapisarda, M.; Perna, S.; Di Gesù, R.; Giorgini, L.; Carbone, D.; Recca, G.; Rizzarelli, P.

    2016-05-01

    Diseases affecting posterior eye segment, like macular edema, infection and neovascularization, may cause visual impairment. Traditional treatments, such as steroidal-drugs intravitreal injections, involve chronic course of therapy usually over a period of years. Moreover, they can require frequent administrations of drug in order to have an adequately disease control. This dramatically reduce patient's compliance. Efforts have been made to develop implantable devices that offer an alternative therapeutic approach to bypass many challenges of conventional type of therapy. Implantable drug delivery systems (DDS) have been developed to optimize therapeutic properties of drugs and ensure their slow release in the specific site. Polymeric materials can play an essential role in modulating drug delivery and their use in such field has become indispensable. During last decades, acrylic polymers have obtained growing interest. Biocompatibility and chemical properties make them extremely versatile, allowing their use in many field such as biomedical. In particular, block methacrylate copolymer with a balance of hydrophilic and hydrophobic properties can be suitable for prolonged DDS in biomedical devices. In this work, we focused on the realization of a system for controlled and long term release of betamethasone 17,21-dipropionate (BDP), a cortisone drug, from methacrylic block copolymers, to be tested in the treatment of the posterior eye's diseases. Different series of methyl methacrylate/hydroxyethyl methacrylate (MMA/HEMA) block and random copolymers, with different monomer compositions (10-60% HEMA), were synthetized by Atom Transfer Radical Polymerization (ATRP) to find the best hydrophilic/hydrophobic ratio, able to ensure optimal kinetic release. Copolymer samples were characterized by NMR spectroscopy (1H-NMR, 13C-NMR, CosY), SEC, TGA and DSC. Monitoring of drug release from films loaded with BDP was carried out by HPLC analysis. Evaluation of different kinetic

  12. Light-induced and sensing capabilities of SI-ATRP modified graphene oxide particles in elastomeric matrix

    Science.gov (United States)

    Osicka, Josef; Cvek, Martin; Mrlik, Miroslav; Ilcikova, Marketa; Pavlinek, Vladimir; Mosnacek, Jaroslav

    2017-04-01

    Photoactuators can concern light stimuli in appropriate wavelength into mechanical response. Such reversible changes in the material shape are highly promising in their applications as remote controllers, or safety sensors. In this work we were focused on light-induced actuation and sensing performance of the prepared materials. In this case poly(dimethyl siloxane) PDMS with various amounts of silicone oil and curing agent was used as matrix. Graphene oxide (GO) as filler in its neat form as well as its modified analogue were used in concentration of 0.1 vol. %. Modified GO particles were controllably coated with poly(methyl methacrylate) polymer chains using surface-initiated atom transfer radical polymerization (SI-ATRP) approach in order improve interactions between the filler and matrix which consequently lead to the enhanced light-induced actuation performance. Generally, the both, GO particles as well as modified ones were characterized using FTIR, Raman spectroscopy and finally conductivity measurement to confirm the controllable coating and simultaneously proceeded reduction. By studying of dielectric properties (activation energies), viscoelastic properties, which were investigated using dynamic mechanical analysis, the interactions between the filler and matrix were evaluated with connection to their light-responsive and sensing capabilities.

  13. Use of Yb-based catalyst for AGET ATRP of acrylonitrile to simultaneously control molecular mass distribution and tacticity.

    Science.gov (United States)

    Ma, Jing; Chen, Hou; Zhang, Min; Wang, Chunhua; Zhang, Ying; Qu, Rongjun

    2012-08-01

    Yb-based catalyst was used for the first time for atom transfer radical polymerization using activators generated by electron transfer (AGET ATRP) of acrylonitrile (AN) with 2-bromopropionitrile (BPN) as initiator, 2, 2'-bipyridine (bipy) as ligand, and tisn(II) bis(2-ethylhexanoate) (Sn(EH)2) as reducing agent in the presence of air. With respect to AGET ATRP of AN catalyzed by CuBr2, an evident increase of polymer tacticity was observed for AGET ATRP of AN. The increase of syndiotacticity became more and more pronounced than the increase of isotacticity of polyacrylonitrile (PAN) along with YbBr3 content. The block copolymer PAN-b-PMMA with molecular weight at 60,000 and polydispersity at 1.36 was successfully prepared. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Rice husk grafted PMAA by ATRP in aqueous phase and its adsorption for Ce3+

    Science.gov (United States)

    Lin, Chao; Luo, Wenjun; Chen, Jindong; Zhou, Qi

    2017-12-01

    A monolithic biomass adsorbent, rice husk grafted poly (methyl acrylic acid) (RH-g-PMAA), was successfully synthesized via surface-initiated atom transfer radical polymerization (ATRP) through heterogeneous reactions in aqueous phase. Its adsorption capacity for Ce3+ reaches 122.51 mg g-1, which is about 12 times higher than that of raw rice husk. The experimental result on desorption and reusability shows that the adsorption capacity is still higher than 100 mg g-1 after six cycles and the desorption rate is almost 100% in every cycle. RH-g-PMAA can be separated from water easily because of its integrity.

  15. A Facile Strategy for Catalyst Separation and Recycling Suitable for ATRP of Hydrophilic Monomers Using a Macroligand.

    Science.gov (United States)

    Jiang, Xiaowu; Wu, Jian; Zhang, Lifen; Cheng, Zhenping; Zhu, Xiulin

    2016-01-01

    How to simply and efficiently separate and recycle catalyst has still been a constraint for the wide application of atom transfer radical polymerization (ATRP), especially for the polymerization systems with hydrophilic monomers because the polar functional groups may coordinate with transition metal salts, resulting in abundant catalyst residual in the resultant water-soluble polymers. In order to overcome this problem, a latent-biphasic system is developed, which can be successfully used for ATRP catalyst separation and recycling in situ for various kinds of hydrophilic monomers for the first time, such as poly(ethylene glycol) monomethyl ether methacrylate (PEGMA), 2-hydroxyethyl methacrylate (HEMA), 2-(dimethylamino)ethyl methacrylate (DMAEMA), N,N-dimethyl acrylamide (DMA), and N-isopropylacrylamide (NIPAM). Herein, random copolymer of octadecyl acrylate (OA), MA-Ln (2-(bis(pyridin-2-ylmethyl)amino)ethyl acrylate), and POA-ran-P(MA-Ln) is designed as the macroligand, and heptane/ethanol is selected as the biphasic solvent. Copper(II) bromide (CuBr2 ) is employed as the catalyst, PEG-bound 2-bromo-2-methylpropanoate (PEG350 -Br) as the water-soluble ATRP initiator and 2,2'-azobis(isobutyronitrile) (AIBN) as the azo-initiator to establish an ICAR (initiators for continuous activator regeneration) ATRP system. Importantly, well-defined water-soluble polymers are obtained even though the recyclable catalyst is used for sixth times. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Iron-Mediated Homogeneous ICAR ATRP of Methyl Methacrylate under ppm Level Organometallic Catalyst Iron(III Acetylacetonate

    Directory of Open Access Journals (Sweden)

    Jian Wu

    2016-01-01

    Full Text Available Atom Transfer Radical Polymerization (ATRP is an important polymerization process in polymer synthesis. However, a typical ATRP system has some drawbacks. For example, it needs a large amount of transition metal catalyst, and it is difficult or expensive to remove the metal catalyst residue in products. In order to reduce the amount of catalyst and considering good biocompatibility and low toxicity of the iron catalyst, in this work, we developed a homogeneous polymerization system of initiators for continuous activator regeneration ATRP (ICAR ATRP with just a ppm level of iron catalyst. Herein, we used oil-soluble iron (III acetylacetonate (Fe(acac3 as the organometallic catalyst, 1,1′-azobis (cyclohexanecarbonitrile (ACHN with longer half-life period as the thermal initiator, ethyl 2-bromophenylacetate (EBPA as the initiator, triphenylphosphine (PPh3 as the ligand, toluene as the solvent and methyl methacrylate (MMA as the model monomer. The factors related with the polymerization system, such as concentration of Fe(acac3 and ACHN and polymerization kinetics, were investigated in detail at 90 °C. It was found that a polymer with an acceptable molecular weight distribution (Mw/Mn = 1.43 at 45.9% of monomer conversion could be obtained even with 1 ppm of Fe(acac3, making it needless to remove the residual metal in the resultant polymers, which makes such an ICAR ATRP process much more industrially attractive. The “living” features of this polymerization system were further confirmed by chain-extension experiment.

  17. Preliminary investigation on hemocompatibility of poly(vinylidene fluoride) membrane grafted with acryloylmorpholine via ATRP.

    Science.gov (United States)

    Shen, Xiang; Liu, Jie; Feng, Xia; Zhao, Yiping; Chen, Li

    2015-02-01

    This work provides a promising way to improve the hemocompatibility of PVDF membrane. An amphiphilic copolymer (PVDF-g-PACMO) having PVDF backbones and poly(N-acryloylmorpholine) (PACMO) side chains was synthesized via atom transfer radical polymerization (ATRP). It is found that the grafting degree of the PACMO increases linearly with the increase of ACMO concentration in the reaction solution. The PVDF-g-PACMO membrane was prepared via immersed phase inversion method. The structure and performances were evaluated by X-ray photoelectron spectroscopy, field emission scanning electron microscopy, water contact angle, and filtration experiment. The hemocompatibility of the membranes were preliminarily investigated by protein adsorption, platelet adhesion, anticoagulant evaluation and hemolysis test. The results indicate that the PVDF membrane functionalized by PACMO can suppress the protein adsorption and platelet adhesion, and shows an improved hemocompatibility. © 2014 Wiley Periodicals, Inc.

  18. Improved Permeate Flux of PVDF Ultrafiltration Membrane Containing PVDF-g-PHEA Synthesized via ATRP

    Directory of Open Access Journals (Sweden)

    Kwang-Mo Kim

    2015-12-01

    Full Text Available Polyvinylidene fluoride (PVDF ultrafiltration (UF membrane combined with polyvinylidene fluoride-graft-2-hydroxyethyl acrylate (PVDF-g-PHEA was fabricated via non-solvent induced phase separation (NIPS. In this study, PVDF-g-PHEA was synthesized via atom transfer radical polymerization (ATRP method, and then synthesized graft copolymer was characterized using Fourier transform infrared spectroscopy (FTIR, nuclear magnetic resonance (NMR and thermogravimetry analysis (TGA. Moreover, PVDF membranes containing graft copolymer (PVDF-g-PHEA showed lower water contact angle value than pristine PVDF membranes. Macrovoid holes were also observed in cross sectional scanning electron microscope (SEM image of PVDF membrane containing PVDF-g-PHEA. Accordingly, it was confirmed that these characteristics led PVDF membrane blended with graft copolymer has high final permeate flux and normalized flux compared to pristine PVDF membrane.

  19. Pentafluorostyrene: A valuable and flexible material design tool when mastered by ATRP

    DEFF Research Database (Denmark)

    Hvilsted, Søren

    Pentafluorostyrene is an intriguing monomer and has turned out to be an indispensable tool in the architecture of various functional materials. The ATRP merits with pentafluorostyrene was revealed a decade ago and since then especially the lability of the para-fluorine of pentafluorostyrene has...... been exploited by the nucleophilic substitution methodology to create numerous other monomers. Two very recent applications have exploited short alkyne initiated poly(pentafluorostyrene)s. The first example is development of polyelectrolyte materials comparable to the industrial fuel cells standard...... by sodium azide treatment. After clicking the two components together the poly(pentafluorostyrene) grafts were phosphonated. Graft copolymer (PSU-g-PhPFS) membranes could be cast that showed high thermal stability and proton conductivity. Soft silicone elastomers are materials in demand for actuators...

  20. Preparation and controlled drug delivery applications of mesoporous silica polymer nanocomposites through the visible light induced surface-initiated ATRP

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Long; Liu, Meiying; Mao, Liucheng; Xu, Dazhuang; Wan, Qing; Zeng, Guangjian; Shi, Yingge [Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China); Wen, Yuanqing, E-mail: m18600788382@163.com [Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China); Zhang, Xiaoyong, E-mail: xiaoyongzhang1980@gmail.com [Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China); Wei, Yen, E-mail: weiyen@tsinghua.edu.cn [Department of Chemistry and The Tsinghua Center for Frontier Polymer Research, Tsinghua University, Beijing, 100084 (China)

    2017-08-01

    Graphical abstract: A novel strategy for surface PEGylation of mesoporous silica nanoparticles was developed based on the light induced surface-initiated atom transfer radical polymerization. - Highlights: • Surface modification of silica nanoparticles through light induced surface-initiated ATRP. • MSNs-NH{sub 2}-poly(IA-co-PEGMA) nanocomposites show high water dispersity. • MSNs-NH{sub 2}-poly(IA-co-PEGMA) nanocomposites are promising for biomedical applications. • The light induced ATRP possesses many advantages as compared with traditional ATRP. - Abstract: The mesoporous materials with large pore size, high specific surface area and high thermal stability have been widely utilized in a variety of fields ranging from environmental remediation to separation and biomedicine. However, surface modification of these silica nanomaterials is required to endow novel properties and achieve better performance for most of these applications. In this work, a new method has been established for surface modification of mesoporous silica nanoparticles (MSNs) that relied on the visible light induced atom transfer radical polymerization (ATRP). In the procedure, the copolymers composited with itaconic acid (IA) and poly(ethylene glycol)methyl acrylate (PEGMA) were grafted from MSNs using IA and PEGMA as the monomers and 10-Phenylphenothiazine(PTH) as the organic catalyst. The successful preparation of final polymer nanocomposites (named as MSNs-NH{sub 2}-poly(IA-co-PEGMA)) were evidenced by a series of characterization techniques. More importantly, the anticancer agent cisplatin can be effectively loaded on MSNs-NH{sub 2}-poly(IA-co-PEGMA) and controlled release it from the drug-loading composites with pH responsive behavior. As compared with conventional ATRP, the light induced surface-initiated ATRP could also be utilized for preparation of various silica polymer nanocomposites under rather benign conditions (e.g. absent of transition metal ions, low polymerization

  1. Optimizing conditions of preparation of thermoresponsive SiO{sub 2}-POEGMA particles via AGET-ATRP

    Energy Technology Data Exchange (ETDEWEB)

    Du, Zhiping, E-mail: duzhiping@sxu.edu.cn [Institute of Resources and Environment Engineering, Shanxi University, No. 92 Wucheng Road, Taiyuan 030006 (China); China Research Institute of Daily Chemical Industry, No.34 Wenyuan Road, Taiyuan 030001 (China); Sun, Xiaofeng; Tai, Xiumei; Wang, Guoyong; Liu, Xiaoying [China Research Institute of Daily Chemical Industry, No.34 Wenyuan Road, Taiyuan 030001 (China)

    2015-02-28

    Graphical abstract: - Highlights: • Thermosensitive SiO{sub 2} nanoparticles were prepared with POEGMA via AGET-ATRP. • Reaction conditions were optimized. • Thermosensitive properties of SiO{sub 2}-POEGMA particles were pronounced. - Abstract: Thermosensitive poly(ethylene glycol) methyl ether methacrylate (POEGMA) was grafted on SiO{sub 2} nanoparticles using activators generated by electron transfer atom transfer radical polymerization (AGET-ATRP) technique. The effects of the amount of ligand, catalyst, ascorbic acid and monomer, as well as the reaction temperature and time were systematically investigated and optimized to get a high grafting density. The structure of the hybrid materials was characterized by Fourier transform infrared (FTIR) spectroscopy, and the morphology was characterized by transmission electron microscopy (TEM) observations. Thermosensitive properties of SiO{sub 2}-POEGMA particles were investigated at different grafting densities by turbidity measurements.

  2. Photoresponsive Azopolyester–PMMA Block Copolymers Obtained by Combination of ATRP, Polycondensation, and “Click” Chemistry

    DEFF Research Database (Denmark)

    Berges, Cristina; Javakhishvili, Irakli; Hvilsted, Søren

    2012-01-01

    azide‐terminated polyesters with different molecular weight (obtained by polycondensation) were coupled to an alkyne‐functionalized PMMA (obtained by ATRP). Blends of the BC with the highest azo content (wt%) and an azopolyester homopolymer were also prepared. All these compounds were investigated...... by polarized light optical microscopy (POM), differential scanning calorimetry (DSC), and transmission electron microscopy (TEM). Polarized light‐induced anisotropy was studied by birefringence and dichroism measurements....

  3. Controlled in situ formation of polyacrylamide hydrogel on PET surface via SI-ARGET-ATRP for wound dressings

    Energy Technology Data Exchange (ETDEWEB)

    Nazari Pour, Sedigheh [Department of Chemistry, Faculty of Science, University of Manitoba, Winnipeg, Canada R3T 2N2 (Canada); Ghugare, Shivkumar V. [Department of Textile Science, Faculty of Human Ecology, University of Manitoba, Winnipeg, Canada R3T 2N2 (Canada); Wiens, Richard; Gough, Kathleen [Department of Chemistry, Faculty of Science, University of Manitoba, Winnipeg, Canada R3T 2N2 (Canada); Liu, Song, E-mail: Song.Liu@umanitoba.ca [Department of Chemistry, Faculty of Science, University of Manitoba, Winnipeg, Canada R3T 2N2 (Canada); Department of Textile Science, Faculty of Human Ecology, University of Manitoba, Winnipeg, Canada R3T 2N2 (Canada); Department of Biosystems Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, Canada R3T 2N2 (Canada)

    2015-09-15

    Graphical abstract: - Highlights: • We grow poly(acrylamide) (PAM) hydrgol from a polymer surface in a controlled way. • Divinyl crosslinker doesn't compromise the control chain growth feature of ARGET-ATRP. • ATR-FTIR-FPA images (spatial resolution 220 nm) reveal a uniform grafting of PAM. • PAM grafted wound dressing can be dual functional: low-adherent and antibacterial. - Abstract: Well-defined polyacrylamide (PAM) hydrogel was synthesized on the surface of poly(ethylene terephthalate) (PET) film via surface-initiated activators regenerated by electron transfer atom transfer radical polymerization (SI-ARGET-ATRP). Following the deposition of an ATRP initiator (2-bromoisobutyrylbromide) on PET film, PAM hydrogel was grafted from the functionalized PET surface via ARGET-ATRP. XPS and FTIR-ATR confirmed that PAM hydrogel was successfully grafted on the PET surface. Results from AFM, SEM, and FTIR-FPA microscopic investigations showed that PAM hydrogel uniformly covers the surface of PET film. The grafting yield increases linearly with increasing reaction time, indicating that the growth of PAM hydrogel on the surface of PET is well controlled. In a cell adhesion assay, PAM hydrogel grafted PET films (PAM hydrogel-g-PET) showed low adhesion to keratinocyte cells. To impart PAM hydrogel-g-PET with antibacterial function, AgNPs were self-assembled along the amide side chains of PAM hydrogel. AgNPs loaded-PAM hydrogel-g-PET shows 99% reduction in the number of multidrug-resistant Pseudomonas aeruginosa within 3 h contact.

  4. The Effect of Covalently-Attached ATRP-Synthesized Polymers on Membrane Stability and Cytoprotection in Human Erythrocytes

    OpenAIRE

    William P Clafshenkel; Hironobu Murata; Jill Andersen; Yehuda Creeger; Koepsel, Richard R; Russell, Alan J

    2016-01-01

    Erythrocytes have been described as advantageous drug delivery vehicles. In order to ensure an adequate circulation half-life, erythrocytes may benefit from protective enhancements that maintain membrane integrity and neutralize oxidative damage of membrane proteins that otherwise facilitate their premature clearance from circulation. Surface modification of erythrocytes using rationally designed polymers, synthesized via atom-transfer radical polymerization (ATRP), may further expand the fie...

  5. Functionalization of graphene and grafting of temperature-responsive surfaces from graphene by ATRP 'on water'

    Energy Technology Data Exchange (ETDEWEB)

    Ren Lulu; Huang Shu; Zhang Chao; Wang Ruiyu [Fudan University, State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science (China); Tjiu, Weng Weei [Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A-STAR) (Singapore); Liu Tianxi, E-mail: txliu@fudan.edu.cn [Fudan University, State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science (China)

    2012-06-15

    Water-dispersible graphene with temperature-responsive surfaces has successfully been synthesized by grafting poly(N-isopropylacrylamide) (PNIPAM) from graphene via surface-initiated atom transfer radical polymerization (ATRP). First, graphene surfaces are functionalized with aminophenol groups by diazonium reaction on water. Subsequently, bromoisobutyrate groups are covalently attached to the phenol-functionalized graphene (G-OH) surface by esterification of 2-bromoisobutyrate with the hydroxyl groups, forming bromoisobutyrate-functionalized graphene (G-Br). Finally, PNIPAM is then grafted from G-Br via ATRP. Data from Raman spectroscopy, {sup 1}H NMR, and transmission electron microscopy (TEM) confirm that PNIPAM chains grow from graphene by ATRP. Thermogravimetric analysis shows that the amount of PNIPAM grown from the graphene increases with the increase of monomer ratios. TEM images also show that functionalized polymer structures (PNIPAM cluster or agglutination) on graphene sheets can be well tuned by controlled polymerization. The obtained graphene-PNIPAM (G-PNIPAM) composite has PNIPAM surface which is highly sensitive to the temperature change. This temperature-responsive and water-dispersible G-PNIPAM composite may find potential applications in environmental devices as well as controlled release drug delivery.

  6. A novel self-catalyzed photoATRP strategy for preparation of fluorescent hydroxyapatite nanoparticles and their biological imaging

    Science.gov (United States)

    Jiang, Ruming; Liu, Meiying; Huang, Hongye; Huang, Long; Huang, Qiang; Wen, Yuanqing; Cao, Qian-yong; Tian, Jianwen; Zhang, Xiaoyong; Wei, Yen

    2018-03-01

    Hydroxyapatite (HAp), as an important biomaterial for the regeneration and reconstruction of bone tissue, has attracted more and more attention of researchers and scientists due to its unique structure and compositions. However, the preparation of fluorescent HAp with controllable morphology has achieved only limited success. In this work, we reported a novel strategy to construct the water dispersible fluorescent HAp nanorods via the combination of ligand exchange and metal-free atom transfer radical polymerization (ATRP). The Br-containing fluorescent HAp nanorods with controllable size and morphology were first prepared through hydrothermal treatment. A multifunctional organic molecule (named as PTH-Br) with aggregation-induced emission feature was immobilized on the surface of hydrophobic HAp nanorods through ligand exchange reaction. The PTH-Br could be used as the initiator and catalyst for surface-initiated metal-free ATRP using poly(ethylene glycol) methacrylate as monomer to obtain hydrophilic fluorescent HAp polymer nanoparticles. This strategy successfully endowed HAp nanorods excellent fluorescence properties and favorable water dispersibility but well preserved their regular morphology. Biological assays demonstrated that the HAp-PTH-poly(PEGMA) nanoparticles exhibited good biocompatibility and efficient cell uptake performance. Taken together, we have developed a rather facile strategy based on the surface ligand exchange reaction and metal-free photoATRP to fabricate fluorescent HAp with controllable size and morphology, high water dispersibility and biological properties. These HAp-PTH-poly(PEGMA) nanoparticles should be novel and promising candidates for biomedical applications.

  7. Preparation and controlled drug delivery applications of mesoporous silica polymer nanocomposites through the visible light induced surface-initiated ATRP

    Science.gov (United States)

    Huang, Long; Liu, Meiying; Mao, Liucheng; Xu, Dazhuang; Wan, Qing; Zeng, Guangjian; Shi, Yingge; Wen, Yuanqing; Zhang, Xiaoyong; Wei, Yen

    2017-08-01

    The mesoporous materials with large pore size, high specific surface area and high thermal stability have been widely utilized in a variety of fields ranging from environmental remediation to separation and biomedicine. However, surface modification of these silica nanomaterials is required to endow novel properties and achieve better performance for most of these applications. In this work, a new method has been established for surface modification of mesoporous silica nanoparticles (MSNs) that relied on the visible light induced atom transfer radical polymerization (ATRP). In the procedure, the copolymers composited with itaconic acid (IA) and poly(ethylene glycol)methyl acrylate (PEGMA) were grafted from MSNs using IA and PEGMA as the monomers and 10-Phenylphenothiazine(PTH) as the organic catalyst. The successful preparation of final polymer nanocomposites (named as MSNs-NH2-poly(IA-co-PEGMA)) were evidenced by a series of characterization techniques. More importantly, the anticancer agent cisplatin can be effectively loaded on MSNs-NH2-poly(IA-co-PEGMA) and controlled release it from the drug-loading composites with pH responsive behavior. As compared with conventional ATRP, the light induced surface-initiated ATRP could also be utilized for preparation of various silica polymer nanocomposites under rather benign conditions (e.g. absent of transition metal ions, low polymerization temperature and short polymerization time). Taken together, we have developed a rather promising strategy method for fabrication of multifunctional MSNs-NH2-poly(IA-co-PEGMA) with great potential for biomedical applications.

  8. Self-assembly of poly(lauryl methacrylate)-b-poly(benzyl methacrylate) nano-objects synthesised by ATRP and their temperature-responsive dispersion properties.

    Science.gov (United States)

    Obeng, Melody; Milani, Amir H; Musa, Muhamad S; Cui, Zhengxing; Fielding, Lee A; Farrand, Louise; Goulding, Mark; Saunders, Brian R

    2017-03-15

    Self-assembling poly(lauryl methacrylate)-b-poly(benzyl methacrylate) (PLMAx-PBzMAy) diblock copolymers were synthesised for the first time using solution atom transfer radical polymerisation (ATRP). The PLMA degree of polymerisation (x) was fixed at 14 and the PBzMA degree of polymerisation (y) was varied from 34 to 74. Post-polymerisation transfer of this new series of diblock copolymers from chloroform into n-dodecane (a poor solvent for PBzMA) resulted in self-assembly of polymeric nano-objects. The morphologies for the latter (spheres, worms and vesicles) were controlled by y. The observed morphologies generally agreed with those reported for related PLMAx-PBzMAy diblock copolymers (x ≥ 16) prepared by polymerisation induced self-assembly (PISA) via reversible addition-fragmentation chain transfer (RAFT) polymerisation (Fielding et al., J. Am. Chem. Soc., 2014, 136, 5790). However, a number of differences were observed such as de-gelation behaviour and the phase boundary positions compared to those expected from Fielding et al. Variable-temperature dynamic light scattering studies for the PLMA14-PBzMA34 spheres revealed that the aggregation number was unaffected by a temperature increase over the range of 20-90 °C, which differed markedly from the behaviour observed for PLMA14-PBzMA64 worms. This difference is a new observation with mechanistic importance for the worm-to-sphere breakdown mechanism. We show that concentrated PLMA14-PBzMAy dispersions (20% w/w) in n-dodecane can be prepared using post-polymerisation transfer. The dispersion with a mixed spherical and worm-like copolymer phase exhibited reversible de-gelation when heated. Surprisingly, the dispersions containing only the worm phase remained as gels (which were white) at temperatures up to 90 °C. Our new ATRP approach for preparing temperature-responsive non-aqueous nano-object dispersions presented here decoupled chain growth and self-assembly and will apply to other copolymer dispersions.

  9. Well-defined functional mesoporous silica/polymer hybrids prepared by an ICAR ATRP technique integrated with bio-inspired polydopamine chemistry for lithium isotope separation.

    Science.gov (United States)

    Liu, Yuekun; Liu, Xuegang; Ye, Gang; Song, Yang; Liu, Fei; Huo, Xiaomei; Chen, Jing

    2017-05-09

    Mesoporous silica/polymer hybrids with well-preserved mesoporosity were prepared by integrating the initiators for continuous activator regeneration (ICAR) atom transfer radical polymerization (ATRP) technique with the bio-inspired polydopamine (PDA) chemistry. By manipulating the auto-oxidative polymerization of dopamine, uniform PDA layers were deposited on the surfaces and pore walls of ordered mesoporous silicas (OMSs), thereby promoting the immobilization of ATRP initiators. Poly(glycidyl methacrylate) (PGMA) brushes were then grown from the OMSs by using the ICAR ATRP technique. The evolution of the mesoporous silica/polymer hybrids during synthesis, in terms of morphology, structure, surface and porous properties, was detailed. And, parameters influencing the controlled growth of polymer chains in the ICAR ATRP system were studied. Taking advantage of the abundant epoxy groups in the PGMA platform, post-functionalization of the mesoporous silica/polymer hybrids by the covalent attachment of macrocyclic ligands for the adsorptive separation of lithium isotopes was realized. Adsorption behavior of the functionalized hybrids toward lithium ions was fully investigated, highlighting the good selectivity, and effects of temperature, solvent and counter ions. The ability for lithium isotope separation was evaluated. A higher separation factor could be obtained in systems with softer counter anions and lower polarity solvents. More importantly, due to the versatility of the ICAR ATRP technique, combined with the non-surface specific PDA chemistry, the methodology established in this work would provide new opportunities for the preparation of advanced organic-inorganic porous hybrids for broadened applications.

  10. Poly(ionic liquid)s-based nanocomposite polyelectrolytes with tunable ionic conductivity prepared via SI-ATRP

    OpenAIRE

    Wang, Ping; Zhou, Yin-Ning; Luo, Jiangshui; Luo, Zheng-Hong

    2014-01-01

    In this study, a novel kind of organic–inorganic core–shell SiO2-poly(p-vinylbenzyl) trimethylammonium tetrafluoroborate (SiO2–P[VBTMA][BF4]) nanoparticle was well designed and successfully synthesized via surface-initiated atom transfer radical polymerization (SI-ATRP). Fourier transform infrared spectroscopy (FT-IR), 1H nuclear magnetic resonance (1H NMR), X-ray photoelectron spectroscopy (XPS), dynamic light scattering (DLS) and scanning electron microscopy (SEM) were used to confirm the f...

  11. The Effect of Covalently-Attached ATRP-Synthesized Polymers on Membrane Stability and Cytoprotection in Human Erythrocytes.

    Science.gov (United States)

    Clafshenkel, William P; Murata, Hironobu; Andersen, Jill; Creeger, Yehuda; Koepsel, Richard R; Russell, Alan J

    2016-01-01

    Erythrocytes have been described as advantageous drug delivery vehicles. In order to ensure an adequate circulation half-life, erythrocytes may benefit from protective enhancements that maintain membrane integrity and neutralize oxidative damage of membrane proteins that otherwise facilitate their premature clearance from circulation. Surface modification of erythrocytes using rationally designed polymers, synthesized via atom-transfer radical polymerization (ATRP), may further expand the field of membrane-engineered red blood cells. This study describes the fate of ATRP-synthesized polymers that were covalently attached to human erythrocytes as well as the effect of membrane engineering on cell stability under physiological and oxidative conditions in vitro. The biocompatible, membrane-reactive polymers were homogenously retained on the periphery of modified erythrocytes for at least 24 hours. Membrane engineering stabilized the erythrocyte membrane and effectively neutralized oxidative species, even in the absence of free-radical scavenger-containing polymers. The targeted functionalization of Band 3 protein by NHS-pDMAA-Cy3 polymers stabilized its monomeric form preventing aggregation in the presence of the crosslinking reagent, bis(sulfosuccinimidyl)suberate (BS3). A free radical scavenging polymer, NHS-pDMAA-TEMPO˙, provided additional protection of surface modified erythrocytes in an in vitro model of oxidative stress. Preserving or augmenting cytoprotective mechanisms that extend circulation half-life is an important consideration for the use of red blood cells for drug delivery in various pathologies, as they are likely to encounter areas of imbalanced oxidative stress as they circuit the vascular system.

  12. Facile iron-mediated dispersant-free suspension polymerization of methyl methacrylate via reverse ATRP in water.

    Science.gov (United States)

    Cao, Jun; Zhang, Lifen; Jiang, Xiaowu; Tian, Chun; Zhao, Xiaoning; Ke, Qi; Pan, Xiangqiang; Cheng, Zhenping; Zhu, Xiulin

    2013-11-01

    An iron-mediated reverse ATRP of methyl methacrylate (MMA) is successfully carried out in water in the absence of any dispersants, using a water-soluble 2,2'-azobis(2-methylpropionamidine) dihydrochloride (V-50) as the initiator and the stabilizer, and using an oil-soluble N,N-butyldithiocarbamate ferrum (Fe(S2 CN(C4 H9 )2 )3 ) as the catalyst without adding any additional ligands. Micron-sized PMMA particles with UV light-sensitive -S2 CN(C4 H9 )2 end group are obtained, and monomer droplet nucleation and suspension polymerization mechanism are proposed. Polymerization results demonstrated typical "living"/controlled characteristics of ATRP: first-order polymerization kinetics, linear increase of molecular weights with monomer conversion and narrow molecular weight distributions for the resultant PMMA particles. NMR spectroscopy and chain-extension experiments under UV light irradiation confirm the attachment and livingness of UV light-sensitive -S2 CN(C4 H9 )2 group in the chain end. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Preparation of hemoglobin (Hb) imprinted polymer by Hb catalyzed eATRP and its application in biosensor.

    Science.gov (United States)

    Sun, Yue; Du, Hongying; Lan, Yuting; Wang, Wenjing; Liang, Yuejian; Feng, Chunliang; Yang, Mei

    2016-03-15

    Molecularly imprinted polymer (MIP) was prepared on the surface of Au electrode by electrochemically mediated atom transfer radical polymerization (eATRP) with hemoglobin (Hb) both as catalyst and template molecule. Firstly, the condition for eATRP such as the potential, time and Hb concentration were selected and determined to be -0.51 V, 120 min and 20mg/mL, respectively. Further, the electrode modified with MIP (MIP/Au) was carefully examined by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM). Finally, the MIP/Au electrode was used as a biosensor and successfully applied for the determination of Hb by differential pulse voltammetry (DPV) measurement. The results of experiments showed that the proposed biosensor displayed a broader linear range and a lower detection limit for Hb determination when it was compared to those Hb sensors based on MIP. The linear range was from 1.0 × 10(-10) to 1.0 × 10(1)mg/L with a detection limit of 7.8 × 10(-11)mg/L (S/N=3.3). In a word, the work of this paper established a useful way for the preparation and application of biosensor based on protein imprinted polymers. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. The Effect of Covalently-Attached ATRP-Synthesized Polymers on Membrane Stability and Cytoprotection in Human Erythrocytes

    Science.gov (United States)

    Clafshenkel, William P.; Murata, Hironobu; Andersen, Jill; Creeger, Yehuda; Russell, Alan J.

    2016-01-01

    Erythrocytes have been described as advantageous drug delivery vehicles. In order to ensure an adequate circulation half-life, erythrocytes may benefit from protective enhancements that maintain membrane integrity and neutralize oxidative damage of membrane proteins that otherwise facilitate their premature clearance from circulation. Surface modification of erythrocytes using rationally designed polymers, synthesized via atom-transfer radical polymerization (ATRP), may further expand the field of membrane-engineered red blood cells. This study describes the fate of ATRP-synthesized polymers that were covalently attached to human erythrocytes as well as the effect of membrane engineering on cell stability under physiological and oxidative conditions in vitro. The biocompatible, membrane-reactive polymers were homogenously retained on the periphery of modified erythrocytes for at least 24 hours. Membrane engineering stabilized the erythrocyte membrane and effectively neutralized oxidative species, even in the absence of free-radical scavenger-containing polymers. The targeted functionalization of Band 3 protein by NHS-pDMAA-Cy3 polymers stabilized its monomeric form preventing aggregation in the presence of the crosslinking reagent, bis(sulfosuccinimidyl)suberate (BS3). A free radical scavenging polymer, NHS-pDMAA-TEMPO˙, provided additional protection of surface modified erythrocytes in an in vitro model of oxidative stress. Preserving or augmenting cytoprotective mechanisms that extend circulation half-life is an important consideration for the use of red blood cells for drug delivery in various pathologies, as they are likely to encounter areas of imbalanced oxidative stress as they circuit the vascular system. PMID:27331401

  15. An Undergraduate Chemistry Laboratory: Synthesis of Well-Defined Polymers by Low-Catalyst-Concentration ATRP and Postpolymerization Modification to Fluorescent Materials

    Science.gov (United States)

    Tsarevsky, Nicolay V.; Woodruf, Shannon R.; Wisian-Neilson, Patty J.

    2016-01-01

    A two-session experiment is designed to introduce undergraduate students to concepts in catalysis, transition metal complexes, polymer synthesis, and postpolymerization modifications. In the first session, students synthesize poly(glycidyl methacrylate) via low-catalyst-concentration atom transfer radical polymerization (ATRP). The…

  16. Surface grafting of zwitterionic polymers onto dye doped AIE-active luminescent silica nanoparticles through surface-initiated ATRP for biological imaging applications

    Science.gov (United States)

    Mao, Liucheng; Liu, Xinhua; Liu, Meiying; Huang, Long; Xu, Dazhuang; Jiang, Ruming; Huang, Qiang; Wen, Yuanqing; Zhang, Xiaoyong; Wei, Yen

    2017-10-01

    Aggregation-induced emission (AIE) dyes have recently been intensively explored for biological imaging applications owing to their outstanding optical feature as compared with conventional organic dyes. The AIE-active luminescent silica nanoparticles (LSNPs) are expected to combine the advantages both of silica nanoparticles and AIE-active dyes. Although the AIE-active LSNPs have been prepared previously, surface modification of these AIE-active LSNPs with functional polymers has not been reported thus far. In this work, we reported a rather facile and general strategy for preparation of polymers functionalized AIE-active LSNPs through the surface-initiated atom transfer radical polymerization (ATRP). The AIE-active LSNPs were fabricated via direct encapsulation of AIE-active dye into silica nanoparticles through a non-covalent modified Stöber method. The ATRP initiator was subsequently immobilized onto these AIE-active LSNPs through amidation reaction between 3-aminopropyl-triethoxy-silane and 2-bromoisobutyryl bromide. Finally, the zwitterionic 2-(methacryloyloxy)ethyl phosphorylcholine (MPC) was selected as model monomer and grafted onto MSNs through ATRP. The characterization results suggested that LSNPs can be successfully modified with poly(MPC) through surface-initiated ATRP. The biological evaluation results demonstrated that the final SNPs-AIE-pMPC composites possess low cytotoxicity, desirable optical properties and great potential for biological imaging. Taken together, we demonstrated that AIE-active LSNPs can be fabricated and surface modified with functional polymers to endow novel functions and better performance for biomedical applications. More importantly, this strategy developed in this work could also be extended for fabrication of many other LSNPs polymer composites owing to the good monomer adoptability of ATRP.

  17. Polymer Molecular Architecture As a Tool for Controlling the Rheological Properties of Aqueous Polyacrylamide Solutions for Enhanced Oil Recovery

    NARCIS (Netherlands)

    Wever, Diego A. Z.; Polgar, Lorenzo M.; Stuart, Marc C. A.; Picchioni, Francesco; Broekhuis, Antonius A.

    2013-01-01

    The controlled synthesis of high molecular weight branched polyacrylamide (PAM) has been accomplished by using atomic transfer radical polymerization (ATRP) of acrylamide (AM) in water at room temperature. Halogen-functionalized aliphatic polyketones acted as macroinitiators in the polymerization.

  18. Star Poly(N-isopropylacrylamide Tethered to Polyhedral Oligomeric Silsesquioxane (POSS Nanoparticles by a Combination of ATRP and Click Chemistry

    Directory of Open Access Journals (Sweden)

    Shiao-Wei Kuo

    2012-01-01

    Full Text Available New star poly(N-isopropylacrylamide-b-polyhedral oligomeric silsesquioxane (PNIPAm-b-POSS copolymers were synthesized from octa-azido functionalized POSS (N3-POSS and alkyne-PNIPAm, which was prepared using an alkyne-functionalized atom transfer radical polymerization (ATRP initiator (propargyl 2-bromo-2-methylpropionamide, via click chemistry. These star PNIPAm-b-POSS copolymers undergo a sharp coil-globule transition in water at above 32°C changing from a hydrophilic state below this temperature to a hydrophobic state above it, which is similar to linear PNIPAm homopolymers. More interestingly, we found that these star polymers exhibited strong blue photoluminescence in water above a lower critical solution temperature (LCST. This photoluminescence was likely due to the constrained geometric freedom and relatively rigid structure caused by intramolecular hydrogen bonding within the star PNIPAm polymers, which exhibit an intrinsic fluorescent behavior.

  19. Facile iron-mediated AGET ATRP for water-soluble poly(ethylene glycol) monomethyl ether methacrylate in water.

    Science.gov (United States)

    He, Weiwei; Zhang, Lifen; Miao, Jie; Cheng, Zhenping; Zhu, Xiulin

    2012-06-27

    An environmentally friendly iron catalyst system was successfully developed in water for the AGET ATRP (activator generated by electron transfer for atom transfer radical polymerization) of water-soluble monomer poly(ethylene glycol) monomethyl ether methacrylate (PEGMA) for the first time. A kinetic study indicated that the polymerization was a living/controlled process in which molecular weight increased linearly with monomer conversion. A lower molecular weight distribution (M(w)/M(n) < 1.5) was maintained. The nontoxic and biocompatible characteristics of the iron catalyst facilitate its mediated polymerization to be used in the preparation of functional polymer materials for biomedical use. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Zwitterionic polymer brushes via dopamine-initiated ATRP from PET sheets for improving hemocompatible and antifouling properties.

    Science.gov (United States)

    Jin, Xingxing; Yuan, Jiang; Shen, Jian

    2016-09-01

    A low-fouling zwitterionic surface strategy has been proven to be promising and effective for repelling nonspecific adsorption of proteins, cells and bacteria, which may eventually induce adverse pathogenic problems such as thrombosis and infection. Herein, a multi-step process was developed by a combination of mussel-inspired chemistry and surface-initiated atom transfer radical polymerization (SI-ATRP) technique for improving hemocompatible and anti-biofouling properties. Polyethylene terephthalate (PET) sheets were first treated with dopamine, and then the bromoalkyl initiators were immobilized on the poly(dopamine) functionalized surfaces, followed by surface-initiated activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) of 2-(dimethylamino) ethyl methacrylate (DMAEMA) monomer. Subsequently, the resulting PET sheets were ring-opening reacted with 1,3-propiolactone (PL) and 1,3-propanesultone (PS) to afford polycarboxybetaine and polysulfobetaine brushes, respectively. Characterizations of the PET sheets were undertaken by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), atomic force microscope (AFM), water contact angle (WCA) measurements, and X-ray photoelectron spectroscopy (XPS) analysis, respectively. The conversion rates of PDMAEMA to polyzwitterions were evaluated by XPS analysis. The remained PDMAEMA(weak cationic) and formed zwitterions(neutral) would form a synergetic antifouling and antibacterial surface. Hemocompatible and anti-biofouling properties were evaluated by total adsorption of protein as well as the adhesion of platelet, cell and bacterium. Zwitterionic polymer brushes grafted PET sheets showed outstanding hemocompatibility featured on reduced platelet adhesion and repelled protein adsorption. Meanwhile, the grafted PET sheets exerted excellent anti-biofouling property characterized by the resisted adhesion of Escherichia coli and 3T3 cells. In summary, zwitterionic

  1. A facile FeBr3 based photoATRP for surface modification of mesoporous silica nanoparticles for controlled delivery cisplatin

    Science.gov (United States)

    Huang, Long; Liu, Meiying; Mao, Liucheng; Huang, Qiang; Huang, Hongye; Zeng, Guangjian; Tian, Jianwen; Wen, Yuanqing; Zhang, Xiaoyong; Wei, Yen

    2018-03-01

    Mesoporous silica nanoparticles (MSNs) should be one of the most important materials for biomedical application owing to their high specific surface area, regular porous structure, adjustable pore size and chemical inert. However, the biomedical applications of unmodified MSNs are largely impeded for their poor hydrophilicity and lack of functional groups. In this work, a novel photo-initiated atom transfer radical polymerization (ATRP) strategy has been reported for modified mesoporous silica nanoparticles (MSNs) with hydrophilicility copolymers using FeBr3 as the novel photocatalyst and itaconic acid (IA) and 2-methacryloyloxyethyl phosphorylcholine (MPC) as monomers. Because of the hydrophilicity and anticancer agent cis-dichlorodiamineplatinum(II) (CDDP) loading capacity of poly(MPC-co-IA), the controlled drug delivery applications MSNs-NH2-poly(MPC-co-IA) composites toward CDDP were further investigated. A series of characterization results demonstrated that MSNs-NH2-poly(MPC-co-IA) composites can be successfully fabricated through the novel photo-initiated ATRP. MSNs-NH2-poly(MPC-co-IA) composites showed obvious enhancement of water dispersibility, desirable biocompatibility, high drug loading capability, making them great potential for controlled drug delivery of CDDP. Moreover, as compared with the traditional ATRP, that using the transition metal ions and organic ligands as the catalysis systems in elevated temperature, our method provides a more facile, benign and cost-effective route for fabrication of multifunctional MSNs with great potential for biomedical applications. Finally, this FeBr3 based photoATRP strategy should be further extended for the fabrication of many other polymeric composites owing to its good monomer adoptability.

  2. PHEA-g-PMMA Well-Defined Graft Copolymer: ATRP Synthesis, Self-Assembly, and Synchronous Encapsulation of Both Hydrophobic and Hydrophilic Guest Molecules.

    Science.gov (United States)

    Ding, Aishun; Xu, Jie; Gu, Guangxin; Lu, Guolin; Huang, Xiaoyu

    2017-10-03

    A series of well-defined amphiphilic graft copolymer bearing a hydrophilic poly(2-hydroxyethyl acrylate) (PHEA) backbone and hydrophobic poly(methyl methacrylate) (PMMA) side chains was synthesized by successive reversible addition-fragmentation chain transfer (RAFT) polymerization and atom transfer radical polymerization (ATRP) through the grafting-from strategy. A well-defined PHEA-based backbone with Cl-containing ATRP initiating group in every repeated unit (M w /M n  = 1.08), poly(2-hydroxyethyl 2-((2-chloropropanoyloxy)methyl)acrylate) (PHECPMA), was first prepared by RAFT homopolymerization of 2-hydroxyethyl 2-((2-chloropropanoyloxy)methyl)acrylate (HECPMA), a Cl-containing trifunctional acrylate. ATRP of methyl methacrylate was subsequently initiated by PHECPMA homopolymer to afford the target well-defined poly(2-hydroxyethyl acrylate)-graft-poly(methyl methacrylate) (PHEA-g-PMMA) graft copolymers (M w /M n  ≤ 1.36) with 34 PMMA side chains and 34 pendant hydroxyls in PHEA backbone using CuCl/dHbpy as catalytic system. The critical micelle concentration (cmc) of the obtained graft copolymer was determined by fluorescence spectroscopy using N-phenyl-1-naphthylamine as probe while micellar morphologies in aqueous media were visualized by transmission electron microscopy. Interestingly, PHEA-g-PMMA graft copolymer could self-assemble into large compound micelles rather than common spherical micelles, which can encapsulate hydrophilic rhodamine 6 G and hydrophobic pyrene separately or simultaneously.

  3. Surface Immobilization of pH-Responsive Polymer Brushes on Mesoporous Silica Nanoparticles by Enzyme Mimetic Catalytic ATRP for Controlled Cargo Release

    Directory of Open Access Journals (Sweden)

    Hang Zhou

    2016-08-01

    Full Text Available Peroxidase mimetic catalytic atom transfer radical polymerization (ATRP was first used to install tertiary amine-functionalized polymer brushes on the surface of mesoporous silica nanoparticles (MSNs in a facile and highly efficient manner. Poly(N,N-dimethylaminoethyl methacrylate (PDMAEMA brushes-grafted MSNs were fabricated by biocompatible deuterohemin-β-Ala-His-Thr-Val-Glu-Lys (DhHP-6-catalyzed surface-initiated ATRP (SI-ATRP. The resulting organic–inorganic hybrid nanocarriers were fully characterized by Fourier transform-infrared spectroscopy (FT-IR, thermogravimetric analysis (TGA, X-ray photoelectron spectroscopy (XPS, powder X-ray diffraction (XRD, SEM, TEM, Elemental analysis, Zeta-potential, and N2 adsorption–desorption isotherms, which demonstrated the successful coating of pH-responsive polymers on the MSN surface. Rhodamine 6G (Rh6G dyes were further loaded within the mesopores of this nanocarrier, and the release of Rh6G out of MSNs in a controlled fashion was achieved upon lowing the solution pH. The electrostatic repulsion of positively-charged tertiary ammonium of PDMAEMAs in acidic environments induced the stretching out of polymer brushes on MSN surfaces, thus opening the gates to allow cargo diffusion out of the mesopores of MSNs.

  4. Preparation of polymeric silica composites through polydopamine-mediated surface initiated ATRP for highly efficient removal of environmental pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Qiang; Liu, Meiying; Wan, Qing; Jiang, Ruming; Mao, Liucheng; Zeng, Guangjian; Huang, Hongye; Deng, Fengjie [Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China); Zhang, Xiaoyong, E-mail: xiaoyongzhang1980@gmail.com [Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China); Wei, Yen [Department of Chemistry and the Tsinghua Center for Frontier Polymer Research, Tsinghua University, Beijing 100084 (China)

    2017-06-01

    In this study, we developed a new procedure to prepare monodispersed functionalized SiO{sub 2} (SiO{sub 2}-PDA-PDMC) composites via mussel inspired chemistry and surface initiated atom transfer radical polymerization (SI-ATRP). Samples were characterized by transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and thermal gravimetric analysis (TGA) measurements. TEM results showed that spherical morphology was unchanged after the functionalization. FT-IR results confirmed the successful modification with polydopamine (PDA) and the presence of poly-([2-(Methacryloyloxy) ethyl] trimethylammonium chloride) (PDMC) layer on the surface of SiO{sub 2} spheres. TGA data showed that the PDMC account for about 12.12 wt% in the sample of SiO{sub 2}-PDA-PDMC composites. The XPS analysis further confirmed the existence of PDMC on the surface of SiO{sub 2}-PDA-PDMC composites. The obtained SiO{sub 2}-PDA-PDMC composites were used as adsorbent for the removal of Congo red (CR) from aqueous solution to evaluate the performance in environment application. The effect of contact time, solution pH, initial CR concentration and temperature on the adsorption of CR onto SiO{sub 2}-PDA-PDMC composites was investigated. Adsorption results demonstrated that adsorption of CR onto SiO{sub 2}-PDA-PDMC composites was a fast and efficient process. The adsorption equilibrium reached within 60 min, and the adsorption process followed the pseudo-second-order model. The experimental data of isotherms were better described by the Freundlich model. Thermodynamic study depicted the endothermic nature of adsorption and the process was spontaneous. Results from the effect of solution pH on the CR adsorption showed that the acidic condition favors the adsorption and provided evidence for the contribution of PDMC on the SiO{sub 2}-PDA-PDMC composites in the removal of CR. This study suggests SiO{sub 2}-PDA-PDMC composites can be

  5. Robust preparation of core-shell type silica/polymer nanocomposites by using surface-initiated ARGET ATRP

    Science.gov (United States)

    Mai, Thanh Binh; Tran, Thi Nga; Kim, Dong Woo; Lim, Kwon Taek; Hong, Seong-Soo; Park, Chan

    2015-01-01

    A facile route for covalent functionalization of silica (SiO2) nanoparticles with poly(methyl methacrylate) (PMMA) has been investigated. The surfaces of the SiO2 nanoparticles were treated with 2-bromo-2-methyl-N-[3-(trimethoxysilyl)propyl] propanamide to introduce the initiator moieties on the surface. Subsequently, activators regenerated by using electron transfer atom transfer radical polymerization (ARGET ATRP) of methyl methacrylate were employed for the preparation of SiO2/PMMA nanocomposites with a CuBr2/ N,N,N', N″,N″-pentamethyldiethylenetriamine catalyst system and a tin(II) 2-ethylhexanoate reducing agent. The modification of SiO2 was confirmed by surface analyses including Fourier transfer infrared spectroscopy and X-ray photoelectron spectroscopy. The morphology of the nanocomposites was investigated by using field-emission scanning electron microscopy and transmission electron microscopy. A thermogravimetric analysis was used to evaluate the thermal properties and the grafting density. The colloidal stability of silica nanoparticles in a common organic solvent was explicitly shown to have been remarkably improved by the grafting process.

  6. Sulfonated amphiphilic block copolymers : synthesis, self-assembly in water, and application as stabilizer in emulsion polymerization

    Science.gov (United States)

    Jiguang Zhang; Matthew R. Dubay; Carl J. Houtman; Steven J. Severtson

    2009-01-01

    Described is the synthesis of diblock copolymers generated via sequential atom transfer radical polymerization (ATRP) of poly(n-butyl acrylate) (PnBA) followed by chain augmentation with either sulfonated poly(2-hydroxyethyl methacrylate) (PHEMA) or poly(2-hydroxyethyl acrylate) (PHEA) blocks. ATRP of PHEMA or PHEA from PnBA macroinitiator was conducted in acetone/...

  7. A versatile method for the preparation of end-functional polymers onto SiO{sub 2} nanoparticles by a combination of surface-initiated ATRP and Huisgen [3 + 2] cycloaddition

    Energy Technology Data Exchange (ETDEWEB)

    Chen, J.C., E-mail: chenjiucun@163.com [Department of Chemistry and Chemical Engineering, Ankang University, 92 Yucai Road, Ankang 725000 (China); Luo, W.Q.; Wang, H.D.; Xiang, J.M.; Jin, H.F. [Department of Chemistry and Chemical Engineering, Ankang University, 92 Yucai Road, Ankang 725000 (China); Chen, F.; Cai, Z.W. [Department of Agriculture and Life Sciences, Ankang University, Ankang 725000 (China)

    2010-02-01

    A versatile method was developed for the chain-end functionalization of the grafted polymer chains for surface modification of nanoparticles with functionalized groups through a combination of surface-initiated atom-transfer radical polymerization (ATRP) and Huisgen [3 + 2] cycloaddition. First, the surface of SiO{sub 2} nanoparticles was modified with poly(methyl methacrylate) (PMMA) brushes via the 'grafting from' approach. The terminal bromides of PMMA-grafted SiO{sub 2} nanoparticles were then transformed into an azide function by nucleophilic substitution. These azido-terminated PMMA brushes on the nanoparticle surface were reacted with alkyne-terminated functional end group via Huisgen [3 + 2] cycloaddition. FTIR and {sup 1}H NMR spectra indicated quantitative transformation of the chain ends of PMMA brushes onto SiO{sub 2} nanoparticles into the desired functional group. And, the dispersibility of the end-functional polymer-grafted SiO{sub 2} nanoparticles was investigated with a transmission electron microscope (TEM).

  8. Synthetic approaches towards new polymer systems by the combination of living carbocationic and anionic polymerizations

    DEFF Research Database (Denmark)

    Feldthusen, Jesper; Ivan, Bela; Muller, Axel. H.E.

    1996-01-01

    Recent efforts to obtain block copolymers by combination of living carbocationic and anionic polymerizations are presented.When tolyl-ended polyisobutylene was used as macroinitiator of anionic polymerization of methacrylate derivatives mixtures of homopolymers and block copolymers were formed due...... to incomplete lithiation of this chain end.In another approach a new functionalization method was developed by end-quenching living polyisobutylene with 1,1-diphenylethylene. After transformation of the groups into 2,2-diphenylvinyl end groups and lithiation polymers were synthesized from protected acrylate...

  9. Photochemically Induced ATRP of (Meth)Acrylates in the Presence of Air: The Effect of Light Intensity, Ligand, and Oxygen Concentration.

    Science.gov (United States)

    Borská, Katarína; Moravčíková, Daniela; Mosnáček, Jaroslav

    2017-07-01

    Well-defined poly(methyl methacrylate) (PMMA) and poly(methyl acrylate) (PMA) are prepared via photochemically induced atom transfer radical polymerization (photoATRP) using ppm amounts of CuBr2 /tris(2-pyridylmethyl)amine and CuBr2 /tris[2-(dimethylamino)ethyl]amine catalyst complexes, respectively, without degassing of polymerization mixture and with no need to introduce an external reducing agent to the system. The effect of ligand to CuBr2 ratio on kinetic and induction period during the polymerization of MMA and MA is investigated. The induction period is influenced also by the amount of oxygen in the polymerization system. Both the kinetics of MA polymerization and the induction period are affected by light intensity. Finally, the high livingness and initiation efficiency of the photoATRP system in the presence of air are proved by chain extension polymerizations. The presented system is valuable from an industrial point of view, since after optimization, well-defined and high-molar-mass poly(meth)acrylates can be prepared without the necessity of degassing the system, while the polymerization can be proceeded quickly and without an induction period. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Immobilization of poly(acrylamide) brushes onto poly(caprolactone) surface by combining ATRP and “click” chemistry: Synthesis, characterization and evaluation of protein adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Yuhao; Bian, Xinxiu; He, Liu; Cai, Mengtan; Xie, Xiaoxiong [College of Polymer Science and Engineering, Sichuan University, Chengdu 610065 (China); Luo, Xianglin, E-mail: luoxl@scu.edu.cn [College of Polymer Science and Engineering, Sichuan University, Chengdu 610065 (China); State Key Laboratory of Polymer Material and Engineering, Sichuan University, Chengdu 610065 (China)

    2015-02-28

    Highlights: • Poly(caprolacone) (PCL) film surface was chemically modified by a novel method through combining ATRP and “click” chemistry. • Poly(acrylamide) (PAAm) of tailored chain length were synthesized and “clicked” onto PCL surface. • The modified PCL surface showed reduced BSA and Fg adsorption, and the protein resist ability in terms of chain length through its impact on grafting reaction and modified surface was investigated. - Abstract: Developments of poly(caprolactone) in blood-contacting applications are often restricted due to its intrinsic hydrophobicity. One common way to improve its hemocompatibility is to attach hydrophilic polymers. Here we developed a non-destructive method to graft hydrophilic poly(acrylamide) (PAAm) onto poly(caprolactone) (PCL) surface. In this strategy, azido-ended PCL with low molecular weights was synthesized and blended with PCL to create a surface with “clickable” property. Alkyne-ended poly(acrylamide)s with controlled chain lengths were then synthesized by atom transfer radical polymerization (ATRP), and finally were immobilized onto PCL surface by “click” reaction. The occurrence of immobilization was verified qualitatively by water contact angle measurement and quantitatively by X-ray photoelectron spectroscopy (XPS). The PAAm grafted surface exhibited fouling resistant properties, as demonstrated by reduced bovine serum albumin (BSA) and fibrinogen (Fg) adhesion.

  11. Synthesis of polyacrylonitrile-grafted cross-linked N-chlorosulfonamidated polystyrene via surface-initiated ARGET ATRP, and use of the resin in mercury removal after modification

    Energy Technology Data Exchange (ETDEWEB)

    Zong Guangxi [School of Chemistry and Materials Science, Ludong University, Hongqi Road 186, Yantai 264025 (China); Chen Hou, E-mail: sdchenhou@hotmail.com [School of Chemistry and Materials Science, Ludong University, Hongqi Road 186, Yantai 264025 (China); Qu Rongjun; Wang Chunhua; Ji Naiyi [School of Chemistry and Materials Science, Ludong University, Hongqi Road 186, Yantai 264025 (China)

    2011-02-15

    A novel method of surface modification was developed via iron (III)-mediated atom transfer radical polymerization, with activators regenerated by electron transfer (ARGET ATRP) on the surfaces of polystyrene resin-supported N-chlorosulfonamide groups. The well-defined polyacrylonitrile (PAN) was grafted onto the surfaces of the polystyrene (PS). The graft reaction exhibited first-order kinetics with respect to the polymerization time in the low-monomer-conversion stage. The cyano group of PAN-g-PS was modified by NH{sub 2}OH.HCl to yield amidoxime (AO) groups. The AO groups had been demonstrated to be an efficient Hg-specific sorbent, which can remove Hg{sup 2+} from solutions. No interference arose from common metal ions, such as Pd{sup 2+}, Ag{sup +}, and Cu{sup 2+}. Three adsorption-desorption cycles demonstrated that this resin is suitable for reuse without any considerable change in adsorption capacity.

  12. Immobilization of poly(MPC) brushes onto titanium surface by combining dopamine self-polymerization and ATRP: Preparation, characterization and evaluation of hemocompatibility in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Wenyong; Yang, Ping; Li, Jingan; Li, Shiqi; Li, Peichuang; Zhao, Yuancong, E-mail: Zhaoyc7320@163.com; Huang, Nan

    2015-09-15

    Graphical abstract: The functional surface containing rich amino and hydroxyl groups was obtained by simple and easily dopamine self-polymerization. Poly (MPC) brushes were successfully immobilized on titanium surface by combining acylation reaction and ATRP. This chemical and biomimetic modified titanium surface effectively inhibits platelet adhesion and activation. - Highlights: • Polydopamine coating provides amino and hydroxyl groups for second reactivity. • Poly(MPC) brushes covalently immobilized on coating by surface initiated ATRP. • In vitro hemocompatibility of biomimetic modified Ti was better than unmodified. - Abstract: Poly(2-methacryloyloxyethyl phosphorylcholine(MPC)) has been studied in many biomedical fields because of good biocompatibility, such as hemocompatibility, inhibiting protein adhesion, antifouling, and so on. To achieve good hemocompatibility of titanium (Ti) surface, bio-inspired poly(MPC) brushes were grafted from Ti substrate covalently. In this work, the surface of Ti was first coated with polydopamine, and got a surface bearing −NH{sub 2} and −OH groups which could be bridged with poly(MPC) via atom transfer radical polymerization. Water contact angle decreased to 51.3° when titanium grafted with poly(MPC) brushes. The data of Infrared Spectroscopy and X-ray photoelectron spectroscopy (XPS) indicated that poly(MPC) was successfully grafted onto the surface of titanium. Platelet-rich plasma (PRP) adhesion test and lactate dehydrogenase (LDH) assay showed that the number of platelets adhered on the surface of modified-titanium was much less than that of unmodified titanium and platelets did not aggregate and distort. Thus, the simple and chemical method of immobilization of poly(MPC) brushes has potential application for improving hemocompatibility for cardiovascular stent and some other biomaterials.

  13. P(HPMA/EGDMA) beads grafted with fibrous chains by SI-ATRP method: agmatine functionalized affinity beads for selective separation of serum albumin.

    Science.gov (United States)

    Bayramoglu, Gulay; Yakup Arica, M

    2014-02-01

    In this paper, novel core-shell polymeric affinity beads based on fibrous grafting and functionalization with a salt resistance affinity ligand were developed to separate and deplete serum albumin (SA) from human serum. Poly(hydroxypropyl methacrylate/ethyleneglycole dimethacrylate), p(HPMA/EGDMA), beads were prepared via suspension polymerization, and were grafted with poly(glycidyl methacrylate) (p(GMA)) via surface-initiated atom transfer radical polymerization (SI-ATRP) method. The grafted p(GMA) fibrous chains on the beads were modified with an affinity ligand (i.e., agmatine). The binding capacity of the affinity beads to SA was determined using aqueous solution of SA in a batch system. Batch adsorption studies showed that the amount of adsorbed SA was found to be 156.7 mg/g at 25 °C. The maximum adsorption capacity for affinity beads was observed at around pH 5.5. Adsorption of SA onto affinity beads significantly increased with increasing temperature, and reached a value 177.8 mg/g beads at 35 °C. The equilibrium data were found to be well described by Langmuir model, while the kinetic data were well fitted to the pseudo-second-order kinetic. The degree of the purity of SA was determined by using HPLC. Before and after adsorption, the peak areas of SA were used in the calculation of separated SA.

  14. Double-bond-containing polyallene-based triblock copolymers via phenoxyallene and (meth)acrylate

    Science.gov (United States)

    Ding, Aishun; Lu, Guolin; Guo, Hao; Huang, Xiaoyu

    2017-03-01

    A series of ABA triblock copolymers, consisting of double-bond-containing poly(phenoxyallene) (PPOA), poly(methyl methacrylate) (PMMA), or poly(butyl acrylate) (PBA) segments, were synthesized by sequential free radical polymerization and atom transfer radical polymerization (ATRP). A new bifunctional initiator bearing azo and halogen-containing ATRP initiating groups was first prepared followed by initiating conventional free radical homopolymerization of phenoxyallene with cumulated double bond to give a PPOA-based macroinitiator with ATRP initiating groups at both ends. Next, PMMA-b-PPOA-b-PMMA and PBA-b-PPOA-b-PBA triblock copolymers were synthesized by ATRP of methyl methacrylate and n-butyl acrylate initiated by the PPOA-based macroinitiator through the site transformation strategy. These double-bond-containing triblock copolymers are stable under UV irradiation and free radical circumstances.

  15. Synthesis of block copolymers derived from N-trityl-(S)-serine and pyrene end-labeled poly(methyl methacrylate) or poly(N-isopropylacrylamide) via ATRP

    Energy Technology Data Exchange (ETDEWEB)

    Buruiana, Emil C., E-mail: emilbur@icmpp.ro [Petru Poni Institute of Macromolecular Chemistry, 41A Gr. Ghica Voda Alley 700487, Iasi (Romania); Podasca, Viorica; Buruiana, Tinca [Petru Poni Institute of Macromolecular Chemistry, 41A Gr. Ghica Voda Alley 700487, Iasi (Romania)

    2012-10-15

    A new monomer bearing N-trityl-L-serine methyl ester in structure, methacryloyloxyethyl carbamoyloxy-N-trityl methyl serine (MTS), was prepared to be further polymerized by atom transfer radical polymerization (ATRP) with pyrene-endcapped poly(methyl methacrylate) (Py-PMMA-Br) or poly(N-isopropylacrylamide) (Py-PNIPA-Br). The resulting block copolymers, poly(methyl methacrylate-block-methacryloyloxyethyl carbamoyloxy-N-trityl methyl serine) (Py-PMMA-b-PMTS) and poly(N-isopropylacrylamide-block-methacryloyloxyethyl carbamoyloxy-N-trityl methyl serine (Py-PNIPA-b-PMTS) were characterized by {sup 1}H ({sup 13}C) NMR, ultraviolet, FTIR and fluorescence spectroscopy, thermal analysis, differential scanning calorimetry (DSC), atomic force microscopy (AFM), scanning electron microscopy (SEM), and gel permeation chromatography (GPC) measurements. The chemical composition in Py-PMMA-b-PMTS was estimated from the {sup 1}H NMR analysis that indicated a ratio of the repeating units of 46:19 (MMA:MTS). For the Py-PNIPA-b-PMTS the composition rate in the copolymer was 61:25 (NIPA:MTS). Quenching of the pyrene species with N,N-diethylaniline, nitrobenzene, nitrophenol, potassium iodide, p-nitrotoluene and tetracyanoquinodimethane (TCNQ) in DMF solution excited at 348 nm was evidenced, more efficiently being nitrophenol and TCNQ. In this case, the monomer emission at 388-409 nm underwent a significant decrease caused of an electron transfer from the electron-reach photoexcited pyrene molecule to the electron-deficient quenchers. - Highlights: Black-Right-Pointing-Pointer Diblock copolymers combine the fluorescence of pyrene-PMMA (PNIPA) with the characteristics of PMTS. Black-Right-Pointing-Pointer Such copolymers could be used for nitroderivatives detecting. Black-Right-Pointing-Pointer UV/vis and fluorescence measurements give a good correlation for LCST of Py-PNIPA-Br.

  16. Preparation and antifouling properties of 2-(meth-acryloyloxy)ethyl cholinephosphate based polymers modified surface with different molecular architectures by ATRP.

    Science.gov (United States)

    Jiang, Yuchen; Su, Yuling; Zhao, Lili; Meng, Fancui; Wang, Quanxin; Ding, Chunmei; Luo, Jianbin; Li, Jianshu

    2017-08-01

    Choline phosphate (CP) containing polymers modified surfaces have been shown good resist to the adhesion of proteins while prompt the attaching of mammalian cells due to the dipole pairing between the CP groups of the polymer and the phosphorylcholine (PC) groups on the cell membrane. However, the antifouling activities of CP modified surface against microbes have not been investigated at present. In addition, CP containing polymers modified surface with different molecular architectures has not been prepared and studied. To this end, glass slides surface modified with two different 2-(meth-acryloyloxy)ethyl cholinephosphate (MCP) containing polymer (PMCP) structures, i.e. brush-like (Glass-PMCP) and bottle brush-like (Glass-PHEMA-g-PMCP) architectures, were prepared in this work by surface-initiated atom transfer radical polymerization (SI-ATRP). The surface physichemical and antifouling properties of the prepared surfaces were characterized and studied. The Glass-PMCP shows improved antifouling properties against proteins and bacteria as compared to pristine glass slides (Glass-OH) and glass slides grafted with poly(2-hydroxyethyl methacrylate) (Glass-PHEMA). Notably, a synergetic fouling resistant properties of PHEMA and PMCP is presented for Glass-PHEMA-g-PMCP, which shows superior antifouling activities over Glass-PHEMA and Glass-PMCP. Furthermore, glass slides containing PMCP, i.e. Glass-PMCP and Glas-PHEMA-g-PMCP, decrease platelet adhesion and prevent their activation significantly. Therefore, the combination of antifouling PHEMA and PMCP into one system holds potential for prevention of bacterial fouling and biomaterial-centered infections. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. AS1411 aptamer and folic acid functionalized pH-responsive ATRP fabricated pPEGMA-PCL-pPEGMA polymeric nanoparticles for targeted drug delivery in cancer therapy.

    Science.gov (United States)

    Lale, Shantanu V; R G, Aswathy; Aravind, Athulya; Kumar, D Sakthi; Koul, Veena

    2014-05-12

    Nonspecificity and cardiotoxicity are the primary limitations of current doxorubicin chemotherapy. To minimize side effects and to enhance bioavailability of doxorubicin to cancer cells, a dual-targeted pH-sensitive biocompatible polymeric nanosystem was designed and developed. An ATRP-based biodegradable triblock copolymer, poly(poly(ethylene glycol) methacrylate)-poly(caprolactone)-poly(poly(ethylene glycol) methacrylate) (pPEGMA-PCL-pPEGMA), conjugated with doxorubicin via an acid-labile hydrazone bond was synthesized and characterized. Dual targeting was achieved by attaching folic acid and the AS1411 aptamer through EDC-NHS coupling. Nanoparticles of the functionalized triblock copolymer were prepared using the nanoprecipitation method, resulting in an average particle size of ∼140 nm. The biocompatibility of the nanoparticles was evaluated using MTT cytotoxicity assays, blood compatibility studies, and protein adsorption studies. In vitro drug release studies showed a higher cumulative doxorubicin release at pH 5.0 (∼70%) compared to pH 7.4 (∼25%) owing to the presence of the acid-sensitive hydrazone linkage. Dual targeting with folate and the AS1411 aptamer increased the cancer-targeting efficiency of the nanoparticles, resulting in enhanced cellular uptake (10- and 100-fold increase in uptake compared to single-targeted NPs and non-targeted NPs, respectively) and a higher payload of doxorubicin in epithelial cancer cell lines (MCF-7 and PANC-1), with subsequent higher apoptosis, whereas a normal (noncancerous) cell line (L929) was spared from the adverse effects of doxorubicin. The results indicate that the dual-targeted pH-sensitive biocompatible polymeric nanosystem can act as a potential drug delivery vehicle against various epithelial cancers such as those of the breast, ovary, pancreas, lung, and others.

  18. Uranium Adsorbent Fibers Prepared by Atom-Transfer Radical Polymerization (ATRP) from Poly(vinyl chloride)- co -chlorinated Poly(vinyl chloride) (PVC- co -CPVC) Fiber

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Suree; Yue, Yanfeng; Kuo, Li-Jung; Mehio, Nada; Li, Meijun; Gill, Gary; Tsouris, Costas; Mayes, Richard T.; Saito, Tomonori; Dai, Sheng

    2016-04-20

    The need to secure future supplies of energy attracts researchers in several countries to a vast resource of nuclear energy fuel: uranium in seawater (estimated at 4.5 billion tons in seawater). In this study, we developed effective adsorbent fibers for the recovery of uranium from seawater via atom-transfer radical polymerization (ATRP) from a poly- (vinyl chloride)-co-chlorinated poly(vinyl chloride) (PVC-co-CPVC) fiber. ATRP was employed in the surface graft polymerization of acrylonitrile (AN) and tert-butyl acrylate (tBA), precursors for uranium-interacting functional groups, from PVC-co-CPVC fiber. The [tBA]/[AN] was systematically varied to identify the optimal ratio between hydrophilic groups (from tBA) and uranyl-binding ligands (from AN). The best performing adsorbent fiber, the one with the optimal [tBA]/[AN] ratio and a high degree of grafting (1390%), demonstrated uranium adsorption capacities that are significantly greater than those of the Japan Atomic Energy Agency (JAEA) reference fiber in natural seawater tests (2.42-3.24 g/kg in 42 days of seawater exposure and 5.22 g/kg in 49 days of seawater exposure, versus 1.66 g/kg in 42 days of seawater exposure and 1.71 g/kg in 49 days of seawater exposure for JAEA). Adsorption of other metal ions from seawater and their corresponding kinetics were also studied. The grafting of alternative monomers for the recovery of uranium from seawater is now under development by this versatile technique of ATRP.

  19. Comparative study of the catalytic activity of the complexes Cp*RuCl(PAr3)2 [Ar = -C6H5 and 4-CF3-C6H4] in the ATRP of styrene

    OpenAIRE

    Villa-Hernández,Alejandro M.; Rosales-Velázquez,Claudia P.; Saldívar-Guerra,Enrique; Torres-Lubián,José R.

    2011-01-01

    Styrene polymerization by ATRP was conducted independently using the complexes Cp*RuCl(PPh3)2, and Cp*RuCl[P(4-CF3-C6H4)3]2 as catalysts, in order to evaluate the influence of the electronic properties of the phosphine ligands on the rate and control of the polymerization. The kinetic data for polymerizations carried out with Cp*RuCl(PPh3)2, show that molecular weights increase linearly with conversion with an average initiation efficiency of 0.77. The molecular weights obtained in the kineti...

  20. Synthesis and characterization of a novel acryl amide-based yttrium imprinted sorbent via the ATRP approach for the preparation of medical-grade {sup 90}Y

    Energy Technology Data Exchange (ETDEWEB)

    Abedi, Mahvash [Nuclear Schience and Technology Research Institute (NSTRI), Tehran (Iran, Islamic Republic of); Shahid Beheshti Univ., Tehran (Iran, Islamic Republic of). Dept. of Chemistry; Shirvani-Arani, Simindokht; Bahrami-Samani, Ali [Nuclear Schience and Technology Research Institute (NSTRI), Tehran (Iran, Islamic Republic of); Nabid, Mohammad Reza [Shahid Beheshti Univ., Tehran (Iran, Islamic Republic of). Dept. of Chemistry

    2016-05-01

    Because of its favorable radionuclidic properties (pure beta emitter, E{sub βmax} = 2.28 MeV, T{sub 1/2} = 64.1 h), the preparation of carrier free {sup 90}Y is of a great importance in radiopharmacy. Herein, we report the synthesis, characterization, and application of a novel yttrium sorbent prepared on the basis of the ion-imprinting concept. The ion-imprinted polymer (IIP) was prepared by atom transfer radical copolymerization of acryl amide (AAm, functional monomer) and N,N'-methylenebisacrylamide (MBAAm) crosslinking agent in the presence of a complex of yttrium ions (template ions) with a homemade chelator, i.e., 2,2-bis(2-bromo-2-methylpropanoate)propane-1,3-disuccinate (also as initiator). For elimination of yttrium ions, which act as the template, the prepared particles were treated with 50% v:v HCl: H{sub 2}O to produce yttrium-imprinted polymeric sorbent. To control the imprinting effect, corresponding non-imprinted particles (NIP) were prepared in a similar manner except that yttrium ions were not used. The synthesized chemicals for the preparation of the chelator-initiator compound and the product itself were assessed in every step using {sup 1}H-NMR analysis. NIP and YIP were subjected to X-ray diffraction (XRD), infra-red spectroscopy (IR) and BET surface area analysis for characterization studies. Sorption/desorption studies were conducted, and the effects of potentially interfering ions, such as Sr{sup 2+} (α = 119.69) and Zr{sup 4+} (α = 73.01) in presence of radio-yttrium, were investigated (particle size: 50-100 μm, resultant recovery of > 99% within 60 min and a capacity of 33.33 mg Y(III) per gram of sorbent). The results showed that amounts of radio-yttrium as low as 250 μg could be extracted effectively with high radionuclidic and radiochemical purity from macro-gram amounts of strontium.

  1. Three-dimensional arrangement of short DNA oligonucleotides at surfaces via the synthesis of DNA-branched polyacrylamide brushes by SI-ATRP.

    Science.gov (United States)

    Henry, Olivier Y F; Mehdi, Ahmed D; Kirwan, Sinead; Sanchez, Josep Luis Acero; O'Sullivan, Ciara K

    2011-09-15

    Short DNA oligonucleotide branches are incorporated into acrylamide brushes via surface initiated atom transfer radical polymerization in an attempt to increase DNA surface density by building three-dimensional molecular architectures. ATR-FTIR as well as hybridization studies followed by SPR confirm the incorporation of the DNA sequences into the polymer backbone. MALDI-TOF analysis further suggests that six acrylamide monomer units are typically separating DNA branches present on a single brushes approximately 26 units long. This new approach offers a promising alternative to SAM-based nucleic acid and aptamer sensors and could enable the realization of more complex soft materials of controlled architecture capable of both recognition and signaling by including additional optically or electrochemically active moieties. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Perfluorocyclobutyl Aryl Ether-Based ABC Amphiphilic Triblock Copolymer

    Science.gov (United States)

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

    2016-12-01

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

  3. Preparation and characterization of poly(glycidyl methacrylate)-grafted magnetic nanoparticles: Effects of the precursor concentration on polyol synthesis of Fe{sub 3}O{sub 4} and [PMDETA]{sub 0}/[CuBr{sub 2}]{sub 0} ratios on SI-AGET ATRP

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Liping; Zhou, Xuyang; Wei, Guyun; Lu, Xiaoduo; Wei, Weiping; Qiu, Jianhua

    2015-12-01

    Highlights: • The nanoparticle size of Fe{sub 3}O{sub 4} increased from 7.3 to 9.6 nm and the saturation magnetization of nanoparticles increased from 59 to 61 emu g{sup −1} with increasing the metal precursor concentration from 0.1 to 0.8 mol L{sup −1}, respectively. • The grafted content of PGMA increased from 4.1 to 23.1 wt% as the [PMDETA]{sub 0}/[CuBr{sub 2}]{sub 0} ratio decreased from 6:1 to 2:1. The PGMA-grafted Fe{sub 3}O{sub 4}@SiO{sub 2} magnetic microparticles were prepared by SI-AGET ATRP. - Abstract: Polymer brushes based on poly(glycidyl methacrylate) (PGMA) have been successfully grafted from the surface of silica coated iron oxide (Fe{sub 3}O{sub 4}@SiO{sub 2}) nanoparticles via surface-initiated activators generated by electron transfer atom transfer radical polymerization (SI-AGET ATRP). The size of the nanoparticles could be adjusted from 7.3 to 9.6 nm by varying the precursor concentration of iron(III) acetylacetonate. The Fe{sub 3}O{sub 4} nanoparticles possessed a highly crystalline structure, and the saturation magnetization of the as-prepared magnetite was strongly related to the particle size. Furthermore, the grafted PGMA content on the magnetic nanoparticles could be controlled by varying the ligand to transition metal ratio in a N,N,N′,N″,N″-pentamethyldiethylenetriamine (PMDETA)/CuBr{sub 2} catalyst system. The maximum grafted content was 23.1% at a ratio of [PMDETA]{sub 0}/[CuBr{sub 2}]{sub 0} = 2:1.

  4. Synthesis of Well-Defined Polyethylene-Based 3-Miktoarm Star Copolymers and Terpolymers

    KAUST Repository

    Zhang, Zhen

    2016-03-25

    Novel polyethylene (PE)-based 3-miktoarm star copolymers A2B, (AB)2B and terpolymers (AC)2(BC) [A: PE; B, C: polystyrene (PS) or poly(methyl methacrylate) (PMMA)] were synthesized by combining boron chemistry, polyhomologation, and atom transfer radical polymerization (ATRP). 1,4-Pentadiene-3-yl 2-bromo-2-methylpropanoate was first synthesized followed by hydroboration with thexylborane to afford B-thexylboracyclanes, a multi-heterofunctional initiator with two initiating sites for polyhomologation and one for ATRP. After polyhomologation of dimethylsulfoxonium methylide the α,ω-dihydroxyl polyethylene (PE-OH)2-Br produced served as macroinitiator for the ATRP of styrene to afford (PE-OH)2-(PS-Br). Both (PE-OH)2-Br and (PE-OH)2-(PS-Br) were transformed to two new trifunctional macroinitiators (PE-Br)2-Br and (PE-Br)2-(PS-Br) through esterification reactions and used for the synthesis of (AB)2B and (AC)2(BC) 3-miktoarm star co/terpolymers. All intermediates and final products were characterized by 1H NMR, high temperature gel permeation chromatography (HT-GPC), and differential scanning calorimetry (DSC). The synthetic method is a general one and can be used for the synthesis of complex PE-based architectures by combination with other living/living-controlled polymerization techniques. © 2016 American Chemical Society.

  5. Synthesis of 1-chloro-1-phenylethyl-telechelic polyisobutylene, a new potential macroinitiator by living cationic polymerization

    DEFF Research Database (Denmark)

    Ivan, Bela; Chen, Xianyi; Kops, Jørgen

    1998-01-01

    mixture at -78 degrees C. After complete isobutylene conversion a small amount of styrene was added leading to a rapid crossover reaction and thus to the attachment of short outer polystyrene (PSt) blocks to the PIB segment. Quenching the living polymerization of styrene yielded 1-chloro-1-phenylethyl...

  6. Fast and Convenient Synthesis of Amine-Terminated Polylactide as a Macroinitiator for ω-Benzyloxycarbonyl-L-Lysine-N-Carboxyanhydrides

    Directory of Open Access Journals (Sweden)

    Mingjie Ju

    2011-01-01

    Full Text Available Amine-terminated poly (L-lactide (NH2-PLLA with various chain lengths were successfully synthesized by sequential tert-butyl-N-(3-hydroxypropyl carbamate initiated bulk ring-opening polymerization (ROP of L-lactide (L-LA in the presence of Stannous(II 2-ethylhexanoate (Sn(Oct2 and deprotection of the N-tert-butoxycarbonyl (Boc group at the end of the polymer chain. The polymers obtained were characterized by FT-IR, 1H NMR, and GPC method. NH2-PLLA thus prepared was used to initiate the polymerization of ω-benzyloxycarbonyl-L-lysine-N-carboxyanhydride (Lys (Z-NCA, and the result confirmed the high nucleophilicity of the terminal amine group. This method was not only suitable for the preparation of low molecular weight NH2-PLLA, but also quite efficient in the synthesis of high molecular weight samples.

  7. Synthesis and Phase Behavior of Poly(N-isopropylacrylamide-b- Poly(L-Lysine Hydrochloride and Poly(N-Isopropylacrylamide- co-Acrylamide-b-Poly(L-Lysine Hydrochloride

    Directory of Open Access Journals (Sweden)

    Milica Spasojević

    2014-07-01

    Full Text Available The synthesis of poly(N-isopropylacrylamide-b-poly(L-lysine and poly(N- isopropylacrylamide-co-acrylamide-b-poly(L-lysine copolymers was accomplished by combining atom transfer radical polymerization (ATRP and ring opening polymerization (ROP. For this purpose, a di-functional initiator with protected amino group was successfully synthetized. The ATRP of N-isopropylacrylamide yielded narrowly dispersed polymers with consistent high yields (~80%. Lower yields (~50% were observed when narrowly dispersed random copolymers of N-isopropylacrylamide and acrylamide where synthesized. Amino-terminated poly(N-isopropylacrylamide and poly(N-isopropylacrylamide- co-acrylamide were successfully used as macroinitiators for ROP of N6-carbobenzoxy-L- lysine N-carboxyanhydride. The thermal behavior of the homopolymers and copolymers in aqueous solutions was studied by turbidimetry, dynamic light scattering (DLS and proton nuclear magnetic resonance spectroscopy (1H-NMR.

  8. Core Cross-Linked Multiarm Star Polymers with Aggregation-Induced Emission and Temperature Responsive Fluorescence Characteristics

    KAUST Repository

    Zhang, Zhen

    2017-05-19

    Aggregation-induced emission (AIE) active core cross-linked multiarm star polymers, carrying polystyrene (PS), polyethylene (PE), or polyethylene-b-polycaprolactone (PE-b-PCL) arms, have been synthesized through an “arm-first” strategy, by atom transfer radical copolymerization (ATRP) of a double styrene-functionalized tetraphenylethene (TPE-2St) used as a cross-linker with linear arm precursors possessing terminal ATRP initiating moieties. Polyethylene macroinitiator (PE–Br) was prepared via the polyhomologation of dimethylsulfoxonium methylide with triethylborane followed by oxidation/hydrolysis and esterification of the produced PE–OH with 2-bromoisobutyryl bromide; polyethylene-block-poly(ε-caprolactone) diblock macroinitiator was derived by combining polyhomologation with ring-opening polymerization (ROP). All synthesized star polymers showed AIE-behavior either in solution or in bulk. At high concentration in good solvents (e.g., THF, or toluene) they exhibited low photoluminescence (PL) intensity due to the inner filter effect. In sharp contrast to the small molecule TPE-2St, the star polymers were highly emissive in dilute THF solutions. This can be attributed to the cross-linked structure of poly(TPE-2St) core which restricts the intramolecular rotation and thus induces emission. In addition, the PL intensity of PE star polymers in THF(solvent)/n-hexane(nonsolvent) mixtures, due to their nearly spherical shape, increased when the temperature decreased from 55 to 5 °C with a linear response in the range 40–5 °C.

  9. Simulating Controlled Radical Polymerizations with mcPolymer—A Monte Carlo Approach

    Directory of Open Access Journals (Sweden)

    Georg Drache

    2012-07-01

    Full Text Available Utilizing model calculations may lead to a better understanding of the complex kinetics of the controlled radical polymerization. We developed a universal simulation tool (mcPolymer, which is based on the widely used Monte Carlo simulation technique. This article focuses on the software architecture of the program, including its data management and optimization approaches. We were able to simulate polymer chains as individual objects, allowing us to gain more detailed microstructural information of the polymeric products. For all given examples of controlled radical polymerization (nitroxide mediated radical polymerization (NMRP homo- and copolymerization, atom transfer radical polymerization (ATRP, reversible addition fragmentation chain transfer polymerization (RAFT, we present detailed performance analyses demonstrating the influence of the system size, concentrations of reactants, and the peculiarities of data. Different possibilities were exemplarily illustrated for finding an adequate balance between precision, memory consumption, and computation time of the simulation. Due to its flexible software architecture, the application of mcPolymer is not limited to the controlled radical polymerization, but can be adjusted in a straightforward manner to further polymerization models.

  10. Novel fluorescent amphiphilic block copolymers: photophysics behavior and interactions with DNA

    Directory of Open Access Journals (Sweden)

    2007-06-01

    Full Text Available In this study, novel amphiphilic fluorescent copolymers poly(N-vinylpyrrolidone-b-poly(N-methacryloyl-N'-(α-naphthylthiourea (PVP-b-PNT were synthesized via ATRP with poly(N-vinylpyrrolidone-Cl as macroinitiator and N-methacryloyl-N'-α-naphthylthiourea (NT as hydrophobic segment. PVP-b-PNT copolymers were characterized by 1H NMR, GPC-MALLS and fluorescence measurements. The aggregation behavior of PVP-b-PNT in water was investigated by transmission electron microscope (TEM and dynamic light scattering (DLS measurement. The photophysics behavior of PVP-b-PNT showed that block copolymer formed strong excimer. The interaction of DNA with the block copolymer made the excimer of block copolymer quench. The cytotoxicity result of PVP-b-PNT in cell culture in vitro indicated that this copolymer PVP-b-PNT had good biocompatibility.

  11. Capability approach

    DEFF Research Database (Denmark)

    Jensen, Niels Rosendal; Kjeldsen, Christian Christrup

    Lærebogen er den første samlede danske præsentation af den af Amartya Sen og Martha Nussbaum udviklede Capability Approach. Bogen indeholder en præsentation og diskussion af Sen og Nussbaums teoretiske platform. I bogen indgår eksempler fra såvel uddannelse/uddannelsespolitik, pædagogik og omsorg....

  12. Pedagogical approaches

    DEFF Research Database (Denmark)

    Lund Larsen, Lea

    in formal settings, but in most teaching settings, the teachers act alone and develop their pedagogical approaches/- teaching strategies with no synchronous sparring from a colleague. Adult learners have particular needs and characteristics that their teachers must be able to address (cf. Knowles......This paper is a part of an on-going qualitative empirical research project: “Teachers of adults as learners. A study on teachers’ experiences in practice”. Data is collected at a Danish Adult Education Centre. The aim of the study is to understand teachers’ learning experiences. The research...... questions are: How (much) and what do teachers learn from experience? And how do teachers of adults develop their pedagogical approach? I examine the field of adult learners from the teachers’ perspective. Firstly, I identify some of the commonly described characteristics of adults as learners...

  13. synthetic approaches

    African Journals Online (AJOL)

    Dr Mdachi

    Avances en Quimica 8: 145-151. Chen J, Zhou L, Tan CK and Yeung Y-Y. 2012 An Enantioselective Approach toward 3,4-Dihydroisocoumarin through the Bromocyclization of Styrene-type. Carboxylic Acids. J. Org. Chem.77: 999-. 1009. Chen P-Y, Wang Y-F, Chen L-Y, Wang G-. L and Wang E-C 2013 Reaction of o-.

  14. Nitroxide mediated and atom transfer radical graft polymerization of atactic polymers onto syndiotactic polystyrene

    Directory of Open Access Journals (Sweden)

    M. Abbasian

    2012-06-01

    Full Text Available 'Living' radical graft polymerization was employed to prepare graft copolymers with nitroxide-mediated arylated syndiotactic polystyrene as the backbone and polystyrene (PS, poly(p-methylstyrene (PMS and poly(methylmethacrylate (PMMA as branches. A two-stage process has been developed to synthesize the macroinitiator. First, syndiotactic polystyrene (sPS was modified by the Friedel-Crafts reaction to introduce chlorine; second, the chlorine groups were converted to nitroxide mediated groups by coupling with 1-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO-OH. The resulting macroinitiator (sPS-TEMPO for 'living' free radical polymerization was then heated in the presence of styrene and p-methylstyrene to form graft and block copolymers. We used the obtained copolymer and N-bromosuccinimide as brominating agent to achieve polymers with bromine groups. This brominated copolymer was used as a macroinitiator for polymerizing methyl methacrylate in the presence of the CuBr/bpy catalyst system. The formation of the graft and block copolymers was confirmed by DSC, ¹H NMR and FTIR spectroscopy. This approach using macroinitiators is an effective method for the preparation of new materials.

  15. Gold Nanoparticles Protected with Thiol-Derivatized Amphiphilic Poly( -caprolactone)-b-poly(acrylic acid)

    DEFF Research Database (Denmark)

    Javakhishvili, Irakli; Hvilsted, Søren

    2008-01-01

    Amphiphilic poly(c-caprolactone)-b-poly(acrylic acid) (HS-PCL-b-PAA) bearing thiol functionality at the PCL terminal has been synthesized by a combination of ring-opening polymerization (ROP) of c-caprolactone (c-CL), esterification of hydroxy chain end with protected mercaptoacetic acid, subsequ......Amphiphilic poly(c-caprolactone)-b-poly(acrylic acid) (HS-PCL-b-PAA) bearing thiol functionality at the PCL terminal has been synthesized by a combination of ring-opening polymerization (ROP) of c-caprolactone (c-CL), esterification of hydroxy chain end with protected mercaptoacetic acid...... distribution (1.09). The hydroxy chain end of Br-PCL-OR was modified by reacting with a-(2,4-dinitrophenylthio)acetic acid or a-(4methoxytritylthio) acetic acid resulting in heterotelechelic PCL incorporating protected thiol and bromoester functionalities. It was then employed as macroinitiator in NiBr2(PPh3......)2 catalysed ATRP of tBA. ATRP of tBA provided diblock copolymers with low polydispersity index (1.17-1.39) while preserving the protected thiol function. Sequential or simultaneous removal of 2,4-dinitrophenyl or 4-methoxytrityl and tert-butyl ester groups resulted in HS-PCL-b-PAA. The PCL backbone remained...

  16. Modification of Jute Fibers with Polystyrene via Atom Transfer Radical Polymerization

    DEFF Research Database (Denmark)

    Plackett, David; Jankova, Katja Atanassova; Egsgaard, Helge

    2005-01-01

    Atom transfer radical polymerization (ATRP) was investigated as a method of covalently bonding polystyrene to jute (Corchorus capsularis) and as a possible approach to fiber composites with enhanced properties. Jute fibers were modified with a brominated initiator and subsequently ATRP modified...... to attach polystyrene and then examined using SEM, DSC, TGA, FTIR, XPS, elemental analysis, and Py-GC-MS. These techniques confirmed that polystyrene had been covalently bound to the fibers and consequently ATRP-modified jute fiber mats were used to prepare hot-pressed polystyrene composites. Composite...... applications, we conclude that further optimization of the ATRP method is required, possibly targeting higher and more uniform loading of polystyrene on the fibers....

  17. Grafting of graphene oxide with stimuli-responsive polymers by using ATRP for drug release

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Shenmin, E-mail: smzhu@sjtu.edu.cn; Li Jingbo; Chen Yuhang [Shanghai Jiao Tong University, State Key Laboratory of Metal Matrix Composites, School of Electronic, Information and Electrical Engineering (China); Chen Zhixin [University of Wollongong, Faculty of Engineering (Australia); Chen Chenxin; Li Yao; Cui Zhaowen; Zhang Di, E-mail: zhangdi@sjtu.edu.cn [Shanghai Jiao Tong University, State Key Laboratory of Metal Matrix Composites, School of Electronic, Information and Electrical Engineering (China)

    2012-09-15

    A thermo-responsive drug delivery system was reported based on grafting of stimuli-responsive poly(N-isopropylacrylamide) (PNIPA) on the surface of graphene oxide (GO) via atom transfer radical polymerization. The successful synthesis of PNIPA attached on GO (GO-PNIPA) was confirmed by X-ray photoelectron spectrum, X-ray diffraction, atomic force microscope, field-emission scanning electron microscopy, and transmission electron microscopy measurements. Control of drug release through the composite GO-PNIPA was performed by measuring the uptake and release of ibuprofen (IBU). It was found the delivery system demonstrated a much high IBU storage of 280 wt%, attributing to the formation of the hydrogen bonding between the polymers on the GO surface and IBU as well as the large number of internal cavities of the PNIPA chains. In vitro test of IBU release exhibited a narrow pronounced transition at around 22 Degree-Sign C, indicating an attractive thermo-sensitive release property of this delivery system. The strategy may pave the way for the use of GO in numerous applications, from drug delivery to thermally responsive micro- and nano-devices.

  18. Self-assembled Block Copolymers with Various Architectures Designed by ATRP

    DEFF Research Database (Denmark)

    Jankova Atanasova, Katja

    networks and demonstrate good Li+ complexation and conductivity. These make the materials a potential for solid electrolyte applications in Li+ ion batteries (4, 6). iii. Amphiphilic water soluble star block copolymers with a polyacrylic acid core form hydrogels at room temperature above concentration 22g.......; Loos, J. J. Polym. Sci., Part A: Polym. Chem. 45, pp 1899-1910 (2007); European Polymer Journal 43, pp 3292-3300 (2007); ibid, 44, pp 72-78 (2008); Journal of Applied Physics 103, 123111 (2008). (4). Jankova, K.; Hvilsted, S. J. Fluorine Chemistry 126(2), pp 241-250 (2005). (5). Hietala, S.; Mononen, P...

  19. Thermoresponsive and Photocrosslinkable PEGMEMA-PPGMA-EGDMA Copolymers from a One-Step ATRP Synthesis

    NARCIS (Netherlands)

    Tai, H.Y.; Wang, W.X.; Vermonden, T.|info:eu-repo/dai/nl/275124517; Heath, F.; Hennink, W.E.|info:eu-repo/dai/nl/070880409; Alexander, C.; Shakesheff, K.M.; Howdle, S.M.

    2009-01-01

    Thermoresponsive and photocrosslinkable polymers can be used as injectable scaffolds in tissue engineering to yield gels in situ with enhanced mechanical properties and stability. They allow easy handling and hold their shapes prior to photopolymerization for clinical practice. Here we report a

  20. ATRP synthesis of poly(2-(methacryloyloxy)ethyl choline phosphate): a multivalent universal biomembrane adhesive.

    Science.gov (United States)

    Yu, Xifei; Yang, Xiaoqiang; Horte, Sonja; Kizhakkedathu, Jayachandran N; Brooks, Donald E

    2013-08-07

    A new monomer, 2-(methacryloyloxy)ethyl choline phosphate, and its direct polymerization into a polyvalent choline phosphate are described, providing a universal biomembrane adhesive exhibiting rapid, strong attachment to any mammalian cell membrane and fast internalization, properties of great value in applications such as tissue engineering and drug delivery.

  1. Antisense RNA Approach

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Antisense RNA Approach. Antisense RNA approach is already well documented and well established in therapeutic research. Our system can also be subjected to such an approach. Which gene to target? Our objective would be to target the leader RNA as is thought ...

  2. Evaluating six soft approaches

    Directory of Open Access Journals (Sweden)

    Lene Sørensen

    2008-09-01

    Full Text Available The paper introduces and evaluates six soft approaches used in strategy development and planning. We take a planner’s perspective on discussing the concepts of strategy development and planning. This means that we see strategy development and planning as learning processes based on Ackoff’s interactive planning principles to be supported by soft approaches in carrying out the principles in action. These six soft approaches are suitable for supporting various steps of the strategy development and planning process. These are the SWOT analysis, the Future Workshop, the Scenario methodology, Strategic Option Development and Analysis, Strategic Choice Approach and Soft Systems Methodology. Evaluations of each methodology are carried out using a conceptual framework in which the organisation, the result, the process and the technology of the specific approach are taken into consideration. Using such a conceptual framework for evaluations of soft approaches increases the understanding of them, their transparency, and their usability in practice.

  3. Alternative Auditing Approaches

    Energy Technology Data Exchange (ETDEWEB)

    Kandt, Alicen J [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-15

    This presentation for the 2017 Energy Exchange in Tampa, Florida, offers information about advanced auditing technologies and techniques including alternative auditing approaches and considerations and caveats.

  4. Revitalizing the setting approach

    DEFF Research Database (Denmark)

    Bloch, Paul; Toft, Ulla; Reinbach, Helene Christine

    2014-01-01

    impact of supersetting initiatives. The supersetting approach is an ecological approach, which places the individual in a social, environmental and cultural context, and calls for a holistic perspective to change potentials and developmental processes with a starting point in the circumstances of people...... approach is based on ecological and whole-systems thinking, and stipulates important principles and values of integration, participation, empowerment, context and knowledge-based development....... in local community settings and on the strengths of social interaction and local ownership as drivers of change processes. Interventions based on a supersetting approach are first and foremost characterised by being integrated, but also participatory, empowering, context-sensitive and knowledge...

  5. The TLC Approach.

    Science.gov (United States)

    Welker, William A.

    2002-01-01

    Notes how the author has developed the Teaching and Learning Cues (TLC) approach, an offspring of textbook organizational patterns instruction that stresses the significance of certain words and phrases in reading. Concludes that with the TLC approach, students learn to appreciate the important role cue words and phrases play in understanding…

  6. Flipped Classroom Approach

    Science.gov (United States)

    Ozdamli, Fezile; Asiksoy, Gulsum

    2016-01-01

    Flipped classroom is an active, student-centered approach that was formed to increase the quality of period within class. Generally this approach whose applications are done mostly in Physical Sciences, also attracts the attention of educators and researchers in different disciplines recently. Flipped classroom learning which wide-spreads rapidly…

  7. Approach behavior as information.

    Science.gov (United States)

    van Uijen, Sophie L; van den Hout, Marcel A; Engelhard, Iris M

    2017-12-01

    Anxious individuals infer danger from information about physiological responses, anxiety responses, and safety behaviors. This study investigated whether anxious individuals also infer safety from approach behavior. 325 students rated the danger they perceived in general and spider-relevant scenarios in which information about objective safety versus objective danger, and approach behavior versus no approach behavior, was varied. A high and low spider fearful group was created with a median split on spider fear. Participants with a high fear of spiders, compared to participants with low spider fear, rated spider scenarios with approach behavior as safer than spider scenarios without approach behavior. This effect was similar for objectively dangerous and safe spider scenarios. No behavior as information effects were found for general scenarios. The data were collected in a non-clinical student sample. Spider fearful individuals infer safety from approach behavior in spider-relevant scenarios. For spider fearful individuals, approach behavior may add to the beneficial effects of exposure therapy. Future research is needed to investigate whether patients with anxiety disorders also show a tendency to infer safety from approach behavior. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Approaches to understand culture

    DEFF Research Database (Denmark)

    Rasmussen, Lauge Baungaard; Rauner, Felix

    1996-01-01

    Different approaches to understand the concept ofculture are presented and evaluated. The author'sconcept of culture is defined. Different aspectsof the concept are discussed.......Different approaches to understand the concept ofculture are presented and evaluated. The author'sconcept of culture is defined. Different aspectsof the concept are discussed....

  9. Stuttering-Psycholinguistic Approach

    Science.gov (United States)

    Hategan, Carolina Bodea; Anca, Maria; Prihoi, Lacramioara

    2012-01-01

    This research promotes psycholinguistic paradigm, it focusing in delimitating several specific particularities in stuttering pathology. Structural approach, on language sides proves both the recurrent aspects found within specialized national and international literature and the psycholinguistic approaches dependence on the features of the…

  10. Evaluating six soft approaches

    DEFF Research Database (Denmark)

    Sørensen, Lene Tolstrup; Vidal, Rene Victor Valqui

    2008-01-01

    's interactive planning principles to be supported by soft approaches in carrying out the principles in action. These six soft approaches are suitable forsupporting various steps of the strategy development and planning process. These are the SWOT analysis, the Future Workshop, the Scenario methodology...

  11. Evaluating six soft approaches

    DEFF Research Database (Denmark)

    Sørensen, Lene; Vidal, Rene Victor Valqui

    2006-01-01

    ’s interactive planning principles to be supported by soft approaches in carrying out the principles in action. These six soft approaches are suitable for supporting various steps of the strategy development and planning process. These are the SWOT analysis, the Future Workshop, the Scenario methodology...

  12. Evaluating Six Soft Approaches

    DEFF Research Database (Denmark)

    Sørensen, Lene Tolstrup; Valqui Vidal, René Victor

    2008-01-01

    's interactive planning principles to be supported by soft approaches in carrying out the principles in action. These six soft approaches are suitable forsupporting various steps of the strategy development and planning process. These are the SWOT analysis, the Future Workshop, the Scenario methodology...

  13. Articulating Design Approaches?

    DEFF Research Database (Denmark)

    Kensing, Finn; Bødker, Keld; Simonsen, Jesper

    We are working on an approach for designing CSCW systems since we advocate the importance of generalizing from own work practice as designers and from studies of designers working under industrial conditions. We use the term approach as something in between commodified methods and isolated techni...

  14. Facile Synthesis of Well-Defined MDMO-PPV Containing (TriBlock—Copolymers via Controlled Radical Polymerization and CuAAC Conjugation

    Directory of Open Access Journals (Sweden)

    Neomy Zaquen

    2015-02-01

    Full Text Available A systematic investigation into the chain transfer polymerization of the so-called radical precursor polymerization of poly(p-phenylene vinylene (PPV materials is presented. Polymerizations are characterized by systematic variation of chain transfer agent (CTA concentration and reaction temperature. For the chain transfer constant, a negative activation energy of −12.8 kJ·mol−1 was deduced. Good control over molecular weight is achieved for both the sulfinyl and the dithiocarbamate route (DTC. PPVs with molecular weights ranging from thousands to ten thousands g·mol−1 were obtained. To allow for a meaningful analysis of the CTA influence, Mark–Houwink–Kuhn–Sakurada (MHKS parameters were determined for conjugated MDMO-PPV ([2-methoxy-5-(3',7'-dimethyloctyloxy]-1,4-phenylenevinylene to α = 0.809 and k = 0.00002 mL·g−1. Further, high-endgroup fidelity of the CBr4-derived PPVs was proven via chain extension experiments. MDMO-PPV-Br was successfully used as macroinitiator in atom transfer radical polymerization (ATRP with acrylates and styrene. A more polar PPV counterpart was chain extended by an acrylate in single-electron transfer living radical polymerization (SET-LRP. In a last step, copper-catalyzed azide alkyne cycloaddition (CuAAC was used to synthesize block copolymer structures. Direct azidation followed by macromolecular conjugation showed only partial success, while the successive chain extension via ATRP followed by CuAAC afforded triblock copolymers of the poly(p-phenylene vinylene-block-poly(tert-butyl acrylate-block-poly(ethylene glycol (PPV-b-PtBuA-b-PEG.

  15. Life Span Developmental Approach

    Directory of Open Access Journals (Sweden)

    Ali Eryilmaz

    2011-03-01

    Full Text Available The Life Span Developmental Approach examines development of individuals which occurs from birth to death. Life span developmental approach is a multi-disciplinary approach related with disciplines like psychology, psychiatry, sociology, anthropology and geriatrics that indicates the fact that development is not completed in adulthood, it continues during the life course. Development is a complex process that consists of dying and death. This approach carefully investigates the development of individuals with respect to developmental stages. This developmental approach suggests that scientific disciplines should not explain developmental facts only with age changes. Along with aging, cognitive, biological, and socioemotional development throughout life should also be considered to provide a reasonable and acceptable context, guideposts, and reasonable expectations for the person. There are three important subjects whom life span developmental approach deals with. These are nature vs nurture, continuity vs discontinuity, and change vs stability. Researchers using life span developmental approach gather and produce knowledge on these three most important domains of individual development with their unique scientific methodology.

  16. Flipped Classroom Approach

    Directory of Open Access Journals (Sweden)

    Fezile Ozdamli

    2016-07-01

    Full Text Available Flipped classroom is an active, student-centered approach that was formed to increase the quality of period within class. Generally this approach whose applications are done mostly in Physical Sciences, also attracts the attention of educators and researchers in different disciplines recently. Flipped classroom learning which wide-spreads rapidly in the world, is not well recognized in our country. That is why the aim of study is to attract attention to its potential in education field and provide to make it recognize more by educators and researchers. With this aim, in the study what flipped classroom approach is, flipped classroom technology models, its advantages and limitations were explained.

  17. The sustainable livelihoods approach

    DEFF Research Database (Denmark)

    Oelofse, Myles; Jensen, Henning Høgh

    2008-01-01

    The rapid development of organic agriculture on a global scale has led to an increased inclusion of producers in developing and transitional countries in the organic food chain. In order to enhance the theoretical frame for the analysis and understanding of the impact that inclusion in the organic...... food chain has on producers and their families, an analysis was conducted of the use of the Sustainable Livelihoods Approach (SLA). The SLA provides a holistic and integrative approach which researchers can use as the overriding frame for their research. The application of the approach is recommended...

  18. Otoplasty: A graduated approach.

    Science.gov (United States)

    Foda, H M

    1999-01-01

    Numerous otoplastic techniques have been described for the correction of protruding ears. Technique selection in otoplasty should be done only after careful analysis of the abnormal anatomy responsible for the protruding ear deformity. A graduated surgical approach is presented which is designed to address all contributing factors to the presenting auricular deformity. The approach starts with the more conservative cartilage-sparing suturing techniques, then proceeds to incorporate other more aggressive cartilage weakening maneuvers. Applying this approach resulted in better long-term results with less postoperative lateralization than that encountered on using the cartilage-sparing techniques alone.

  19. Approach behavior as information

    NARCIS (Netherlands)

    van Uijen, Sophie L.; van den Hout, Marcel A.; Engelhard, Iris M.

    2017-01-01

    Background and objectives Anxious individuals infer danger from information about physiological responses, anxiety responses, and safety behaviors. This study investigated whether anxious individuals also infer safety from approach behavior. Methods 325 students rated the danger they perceived in

  20. The transformativity approach

    DEFF Research Database (Denmark)

    Holm, Isak Winkel; Lauta, Kristian Cedervall

    2017-01-01

    an identifiable and promising approach for future disaster research. We suggest naming it the transformativity approach. Whereas the vulnerability approach explores the social causation of disasters, the transformativity approach reverses the direction of the gaze and investigates the social transformation...... brought about by disasters. Put simply, the concept of vulnerability is about the upstream causes of disaster and the concept of transformativity about the downstream effects. By discussing three recent contributions (by the historian Greg Bankoff, the legal sociologist Michelle Dauber......During the last five to ten years, a considerable body of research has begun to explore how disasters, real and imagined, trigger social transformations. Even if the contributions to this this research stems from a multitude of academic disciplines, we argue in the article, they constitute...

  1. The case study approach

    Science.gov (United States)

    2011-01-01

    The case study approach allows in-depth, multi-faceted explorations of complex issues in their real-life settings. The value of the case study approach is well recognised in the fields of business, law and policy, but somewhat less so in health services research. Based on our experiences of conducting several health-related case studies, we reflect on the different types of case study design, the specific research questions this approach can help answer, the data sources that tend to be used, and the particular advantages and disadvantages of employing this methodological approach. The paper concludes with key pointers to aid those designing and appraising proposals for conducting case study research, and a checklist to help readers assess the quality of case study reports. PMID:21707982

  2. Alternate approach slab reinforcement.

    Science.gov (United States)

    2010-06-01

    The upper mat of reinforcing steel, in exposed concrete bridge approach slabs, is prone to corrosion damage. Chlorides applied to the highways : for winter maintenance can penetrate this concrete layer. Eventually chlorides reach the steel and begin ...

  3. Climate Change Adaptation Approaches

    Science.gov (United States)

    2011-05-11

    US Army Corps of Engineers BUILDING STRONG® Climate Change Adaptation Approaches Presented at the E2S2 Symposium May 11th, 2011 New Orleans, LA...COVERED 00-00-2011 to 00-00-2011 4. TITLE AND SUBTITLE Climate Change Adaptation Approaches 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM...10/09).  One of the four priorities is to maintain readiness in the face of climate change .  Addressing Climate Change Risk and Vulnerability: a

  4. Sustainable fashion: New approaches

    OpenAIRE

    Niinimäki, Kirsi

    2013-01-01

    This publication is intended to be used as a source of inspiration for designers and companies, and all stakeholders whose interest lies in the area of sustainable fashion. While the strategies for sustainability are complex and approaches are many, this publication presents only a few ways to approach sustainable fashion. I hope the publication offers inspiration on how to make positive change in current practices and how to effect new mindsets, creating transformative fashion. Theoretica...

  5. Multidisciplinary Approach to Obesity

    OpenAIRE

    Berna Bulut Çakmak; Aslýhan DÖNMEZ

    2014-01-01

    Obesity is a world wide public health problem which increases morbidity and mortality. A multidiciplinary approach is increasingly becoming important for treatment of obesity. Pharmacological agents, sergery, and cognitive behavioral terapy (CBT) are the recommended treatment approaches. In this review, these treatment modalities are reviewed. In CBT of obesity, the dysfunctional thoughts and behaviors which prevent the person for losing weight or doing exercise opr which cause gaining back t...

  6. A supervised approach

    OpenAIRE

    Khoramshahi, Ehsan; Hietaoja, Juha; Valros, Anna; Yun, Jinhyeon; Pastell, Matti

    2014-01-01

    This paper proposes a supervised classification approach for the real-time pattern recognition of sows in an animal supervision system (asup). Our approach offers the possibility of the foreground subtraction in an asup’s image processing module where there is lack of statistical information regarding the background. A set of 7 farrowing sessions of sows, during day and night, have been captured (approximately 7 days/sow), which is used for this study. The frames of these recordings have been...

  7. Flipped Classroom Approach

    OpenAIRE

    Fezile Ozdamli; Gulsum Asiksoy

    2016-01-01

    Flipped classroom is an active, student-centered approach that was formed to increase the quality of period within class. Generally this approach whose applications are done mostly in Physical Sciences, also attracts the attention of educators and researchers in different disciplines recently. Flipped classroom learning which wide-spreads rapidly in the world, is not well recognized in our country. That is why the aim of study is to attract attention to its potential in education field and pr...

  8. Theoretical Approaches to Coping

    Directory of Open Access Journals (Sweden)

    Sofia Zyga

    2013-01-01

    Full Text Available Introduction: Dealing with stress requires conscious effort, it cannot be perceived as equal to individual's spontaneous reactions. The intentional management of stress must not be confused withdefense mechanisms. Coping differs from adjustment in that the latter is more general, has a broader meaning and includes diverse ways of facing a difficulty.Aim: An exploration of the definition of the term "coping", the function of the coping process as well as its differentiation from other similar meanings through a literature review.Methodology: Three theoretical approaches of coping are introduced; the psychoanalytic approach; approaching by characteristics; and the Lazarus and Folkman interactive model.Results: The strategic methods of the coping approaches are described and the article ends with a review of the approaches including the functioning of the stress-coping process , the classificationtypes of coping strategies in stress-inducing situations and with a criticism of coping approaches.Conclusions: The comparison of coping in different situations is difficult, if not impossible. The coping process is a slow process, so an individual may select one method of coping under one set ofcircumstances and a different strategy at some other time. Such selection of strategies takes place as the situation changes.

  9. Functionalized polymer film surfaces via surface-initiated atom transfer radical polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Y. [State Key Laboratory of Chemical Resource Engineering, Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Li, J.S. [College of Polymer Science and Engineering, Sichuan University, Chengdu 610065 (China); Yang, W.T. [State Key Laboratory of Chemical Resource Engineering, Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Xu, F.J., E-mail: xufj@mail.buct.edu.cn [State Key Laboratory of Chemical Resource Engineering, Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China)

    2013-05-01

    The ability to manipulate and control the surface properties of polymer films, without altering the substrate properties, is crucial to their wide-spread applications. In this work, a simple one-step method for the direct immobilization of benzyl chloride groups (as the effective atom transfer radical polymerization (ATRP) initiators) on the polymer films was developed via benzophenone-induced coupling of 4-vinylbenzyl chloride (VBC). Polyethylene (PE) and nylon films were selected as examples of polymer films to illustrate the functionalization of film surfaces via surface-initiated ATRP. Functional polymer brushes of (2-dimethylamino)ethyl methacrylate, sodium 4-styrenesulfonate, 2-hydroxyethyl methacrylate and glycidyl methacrylate, as well as their block copolymer brushes, have been prepared via surface-initiated ATRP from the VBC-coupled PE or nylon film surfaces. With the development of a simple approach to the covalent immobilization of ATRP initiators on polymer film surfaces and the inherent versatility of surface-initiated ATRP, the surface functionality of polymer films can be precisely tailored. - Highlights: ► Atom transfer radical polymerization initiators were simply immobilized. ► Different functional polymer brushes were readily prepared. ► Their block copolymer brushes were also readily prepared.

  10. Approaching a Postcolonial Arctic

    DEFF Research Database (Denmark)

    Jensen, Lars

    2016-01-01

    This article explores different postcolonially configured approaches to the Arctic. It begins by considering the Arctic as a region, an entity, and how the customary political science informed approaches are delimited by their focus on understanding the Arctic as a region at the service of the co......-colonial presences in the Arctic before moving on to consider artworks about the Arctic that arguably through their transgressive forms pushes at the boundaries of geopolitical, geohistorical and geoaesthetic approaches.......This article explores different postcolonially configured approaches to the Arctic. It begins by considering the Arctic as a region, an entity, and how the customary political science informed approaches are delimited by their focus on understanding the Arctic as a region at the service...... of the contemporary neoliberal order. It moves on to explore how different parts of the Arctic are inscribed in a number of sub-Arctic nation-state binds, focusing mainly on Canada and Denmark. The article argues that the postcolonial can be understood as a prism or a methodology that asks pivotal questions to all...

  11. New Approaches to Robotics

    Science.gov (United States)

    Brooks, Rodney A.

    1991-09-01

    In order to build autonomous robots that can carry out useful work in unstructured environments new approaches have been developed to building intelligent systems. The relationship to traditional academic robotics and traditional artificial intelligence is examined. In the new approaches a tight coupling of sensing to action produces architectures for intelligence that are networks of simple computational elements which are quite broad, but not very deep. Recent work within this approach has demonstrated the use of representations, expectations, plans, goals, and learning, but without resorting to the traditional uses of central, abstractly manipulable or symbolic representations. Perception within these systems is often an active process, and the dynamics of the interactions with the world are extremely important. The question of how to evaluate and compare the new to traditional work still provokes vigorous discussion.

  12. Approaches to Methadone Treatment

    DEFF Research Database (Denmark)

    Järvinen, Margaretha

    2008-01-01

    The paper analyses methadone treatment in Copenhagen – as it is described by methadone users and staff at different outpatient centres. The starting point is a theoretical model distinguishing between two different approaches to methadone treatment: ‘palliative’ and ‘curative’. Included...... in the model are three dimensions (1) treatment goals at the methadone centres (abstinence vs. stabilisation) (2) treatment focus (focus on addiction vs. focus on the consequences of addiction) and (3) conceptualisation of methadone (methadone as similar to or different from heroin). The paper shows...... that there is a discrepancy between the attitudes of the staff and those of the users. While the staff favour an almost clear-cut palliative approach to methadone treatment, defining curative goals as both unrealistic and as belonging to the past, the users prefer an approach that does not exclude the goal of abstinence...

  13. DMFC Performance of Polymer Electrolyte Membranes Prepared from a Graft-Copolymer Consisting of a Polysulfone Main Chain and Styrene Sulfonic Acid Side Chains

    Directory of Open Access Journals (Sweden)

    Nobutaka Endo

    2016-08-01

    Full Text Available Polymer electrolyte membranes (PEMs for direct methanol fuel cell (DMFC applications were prepared from a graft-copolymer (PSF-g-PSSA consisting of a polysulfone (PSF main chain and poly(styrene sulfonic acid (PSSA side chains with various average distances between side chains (Lav and side chain lengths (Lsc. The polymers were synthesized by grafting ethyl p-styrenesulfonate (EtSS on macro-initiators of chloromethylated polysulfone with different contents of chloromethyl (CM groups, and by changing EtSS content in the copolymers by using atom transfer radical polymerization (ATRP. The DMFC performance tests using membrane electrode assemblis (MEAs with the three types of the PEMs revealed that: a PSF-g-PSSA PEM (SF-6 prepared from a graft copolymer with short average distances between side chains (Lav and medium Lsc had higher DMFC performance than PEMs with long Lav and long Lsc or with short Lav and short Lsc. SF-6 had about two times higher PDmax (68.4 mW/cm2 than Nafion® 112 at 30 wt % of methanol concentration. Furthermore, it had 58.2 mW/cm2 of PDmax at 50 wt % of methanol concentration because of it has the highest proton selectivity during DMFC operation of all the PSF-g-PSSA PEMs and Nafion® 112.

  14. Comparison of Hydrolytic Resistance of Polyurethanes and Poly(Urethanemethacrylate Copolymers in Terms of their Use as Polymer Coatings in Contact with the Physiological Liquid

    Directory of Open Access Journals (Sweden)

    Król Piotr

    2014-06-01

    Full Text Available PU elastomers were synthesized using MDI, PTMO, butane-1,4-diol or 2,2,3,3-tetrafiuorobutane-1,4-diol. Using the same diisocyanate and polyether reagents urethane segments were prepared, to be inserted in the poly(urethane-methacrylate copolymers. Bromourethane or tetraphenylethane-urethane macroinitiators were used as transitional products reacting with MMA according to the ARGET ATRP. 1H and 13C NMR spectral methods, as well as DSC and TGA thermal methods, were employed to confirm chemical structures of synthesised elastomers and copolymers. To investigate the possibility of using synthesized polymers as biomaterials a research on keeping them in physiological liquid at 37°C was performed. A loss in weight and ability to sorption of water was determined and by using GPC the molecular weight changes were compared. Additionally, changes in the thermal properties of the samples after exposure in physiological liquid were documented using both the TGA and DSC methods. The studies of surface properties (confocal microscopy and SFE of the obtained polymers were performed. The structure of the polymer chains was defined by NMR. Possible reasons of hydrolysis were discussed, stating that new copolymers are more resistant and polar biomaterials can be less interesting than elastomers.

  15. New poly(dimethylsiloxane)/poly(perfluorooctylethyl acrylate) block copolymers: structure and order across multiple length scales in thin films

    KAUST Repository

    Martinelli, Elisa

    2011-01-01

    Three sets of a new class of low surface tension block copolymers were synthesized consisting of a poly(dimethylsiloxane) (PDMS) block and a poly(perfluorooctylethyl acrylate) (AF8) block. The polymers were prepared using a bromo-terminated PDMS macroinitiator, to which was attached an AF8 block grown using atom transfer radical polymerization (ATRP) in such a designed way that the molecular weight and composition of the two polymer blocks were regularly varied. The interplay of both the phase separated microstructure and the mesomorphic character of the fluorinated domains with their effect on surface structure was evaluated using a suite of analytical tools. Surfaces of spin-coated and thermally annealed films were assessed using a combination of X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) studies. Both atomic force microscopy (AFM) measurements and grazing incidence small angle X-ray scattering (GISAXS) studies were carried out to evaluate the microstructure of the thin films. Even in block copolymers in which the PDMS block was the majority component, a significant presence of the lower surface energy AF8 block was detected at the film surface. Moreover, the perfluorooctyl helices of the AF8 repeat units were highly oriented at the surface in an ordered, tilted smectic structure, which was compared with those of the bulk powder samples using wide-angle X-ray powder diffraction (WAXD) studies. © 2011 The Royal Society of Chemistry.

  16. Personal Approaches to Career Planning.

    Science.gov (United States)

    DeMont, Billie; DeMont, Roger

    1983-01-01

    Identifies four approaches to career planning based on situational leadership theory: the network approach, self-help approach, engineering approach, and mentor approach. Guidelines for the selection of a planning method based on the nature of the work environment and personal preference are discussed. (JAC)

  17. Technical approach document

    Energy Technology Data Exchange (ETDEWEB)

    1989-12-01

    The Uranium Mill Tailings Radiation Control Act (UMTRCA) of 1978, Public Law 95-604 (PL95-604), grants the Secretary of Energy the authority and responsibility to perform such actions as are necessary to minimize radiation health hazards and other environmental hazards caused by inactive uranium mill sites. This Technical Approach Document (TAD) describes the general technical approaches and design criteria adopted by the US Department of Energy (DOE) in order to implement remedial action plans (RAPS) and final designs that comply with EPA standards. It does not address the technical approaches necessary for aquifer restoration at processing sites; a guidance document, currently in preparation, will describe aquifer restoration concerns and technical protocols. This document is a second revision to the original document issued in May 1986; the revision has been made in response to changes to the groundwater standards of 40 CFR 192, Subparts A--C, proposed by EPA as draft standards. New sections were added to define the design approaches and designs necessary to comply with the groundwater standards. These new sections are in addition to changes made throughout the document to reflect current procedures, especially in cover design, water resources protection, and alternate site selection; only minor revisions were made to some of the sections. Sections 3.0 is a new section defining the approach taken in the design of disposal cells; Section 4.0 has been revised to include design of vegetated covers; Section 8.0 discusses design approaches necessary for compliance with the groundwater standards; and Section 9.0 is a new section dealing with nonradiological hazardous constituents. 203 refs., 18 figs., 26 tabs.

  18. Logotherapeutic approach to depression

    OpenAIRE

    Vidović, Boris

    2016-01-01

    In this paper we will deal with depression, i.e. depression dis- order, and the possibility that the logo-therapy of Viktor E. Frankl offers in understudying and processing the treatment of this dis- order. According to some indicators, depression is one of the most widespread diseases of our time and deserves to be discussed about considering the logo-therapeutic approach. The specificity of this approach is to understand the human being as a psycho-somatic- spiritual being. Starting from th...

  19. Financial Management: An Organic Approach

    Science.gov (United States)

    Laux, Judy

    2013-01-01

    Although textbooks present corporate finance using a topical approach, good financial management requires an organic approach that integrates the various assignments financial managers confront every day. Breaking the tasks into meaningful subcategories, the current article offers one approach.

  20. Thematic curriculum approach

    Directory of Open Access Journals (Sweden)

    Šefer Jasmina P.

    2003-01-01

    Full Text Available Thematic curriculum combines disciplines and media. The process is problem-oriented and the scenario most often follows the logic of exploring or storytelling. Those two approaches to teaching are appropriate because they fit into interdisciplinary and creative open-ended problem solving through play, as insisted upon by thematic curriculum. The matrix, where seven types of abilities intersect with five types of problems according to their degree of openness, defines well the outcomes of teaching. However, it did not prove to be suitable for planning the majority of activities in thematic curriculum, for it follows with difficulty the process of exploring or storytelling i.e. it disrupts the subject matter coherence of thematic curriculum. Therefore, it is suggested that matrix should be used for disciplinary curriculum planning but for that of thematic curriculum only in exclusive cases. The matrix should be used primarily as a framework for evaluating the distribution of various types of abilities and problem situations in teaching. The logic of diverse approaches to teaching reflects itself in the manner of planning and organizing the teaching process. Conceptual, visual-graphic, structural and other aids employed during educational process planning should suit the nature of the approach chosen. On the basis of qualitative investigations of educational process, in the present paper considerations are given to various approaches to teaching development of various drafts for the planning of teaching, and recognition of the logic of storytelling and exploring in thematic curriculum.

  1. Ethical Approaches to Compliance

    Science.gov (United States)

    Buzo, Carina

    2017-01-01

    This article explores the role that higher education has in ethical compliance to Title IX and the Clery Act. The discussion includes a curious look at common practices as potential future approaches to consent and sexual assault education. Articles and research are included to ground understanding in the current context, while examples from a…

  2. The Capability Approach

    NARCIS (Netherlands)

    I.A.M. Robeyns (Ingrid)

    2011-01-01

    textabstract In its most general description, the capability approach is a flexible and multi-purpose normative framework, rather than a precise theory of well-being, freedom or justice. At its core are two normative claims: first, the claim that the freedom to achieve well-being is of primary

  3. Orion Emergency Mask Approach

    Science.gov (United States)

    Tuan, George C.; Graf, John C.

    2009-01-01

    Emergency mask approach on Orion poses a challenge to the traditional Shuttle or Station approaches. Currently, in the case of a fire or toxic spill event, the crew utilizes open loop oxygen masks that provide the crew with oxygen to breath, but also dumps the exhaled oxygen into the cabin. For Orion, with a small cabin volume, the extra oxygen will exceed the flammability limit within a short period of time, unless a nitrogen purge is also provided. Another approach to a fire or toxic spill event is the use of a filtering emergency masks. These masks utilize some form of chemical beds to scrub the air clean of toxic providing the crew safe breathing air for a period without elevating the oxygen level in the cabin. Using the masks and a form of smoke-eater filter, it may be possible to clean the cabin completely or to a level for safe transition to a space suit to perform a cabin purge. Issues with filters in the past have been the reaction time, breakthroughs, and high breathing resistance. Development in a new form of chemical filters has shown promise to make the filtering approach feasible.

  4. Approach to Absolute Zero

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 10. Approach to Absolute Zero Below 10 milli-Kelvin. R Srinivasan. Series Article Volume 2 Issue 10 October 1997 pp 8-16. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/002/10/0008-0016 ...

  5. Approach To Absolute Zero

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 12. Approach to Absolute Zero Liquefaction of Gases. R Srinivasan. Series Article Volume 1 Issue 12 December 1996 pp 6-16. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/001/12/0006-0016 ...

  6. CURRENT APPROACH TO SINUSITIS

    African Journals Online (AJOL)

    Enrique

    scopic or external spheno-eth- moidectomy. Complications of ABRS. Orbital complications are the most common complication of sinusitis. The Chandler classification gives a clinical approach to orbital inflamma- tion: • inflammatory oedema (lid oedema). • orbital cellulitis (diffuse oedema). • subperiosteal abscess (displace-.

  7. Approaches to Machine Learning.

    Science.gov (United States)

    Langley, Pat; Carbonell, Jaime G.

    1984-01-01

    Reviews approaches to machine learning (development of techniques to automate acquisition of new information, skills, and ways of organizing existing information) in symbolic domains. Four categorical tasks addressed in machine learning literature are examined: learning from examples, learning search heuristics, learning by observation, and…

  8. Approaches to Contrastive Linguistics.

    Science.gov (United States)

    Akhmanova, Olga; And Others

    Linguistics as a science has been concerned with comparison ever since its inception, the number and variety of approaches increasing steadily in the course of its development. Interest in linguistic comparison extends into the field of foreign language teaching. Linguists have attempted to solve the problem of methodology in contrastive…

  9. Approaches to acceptable risk

    Energy Technology Data Exchange (ETDEWEB)

    Whipple, C.

    1997-04-30

    Several alternative approaches to address the question {open_quotes}How safe is safe enough?{close_quotes} are reviewed and an attempt is made to apply the reasoning behind these approaches to the issue of acceptability of radiation exposures received in space. The approaches to the issue of the acceptability of technological risk described here are primarily analytical, and are drawn from examples in the management of environmental health risks. These include risk-based approaches, in which specific quantitative risk targets determine the acceptability of an activity, and cost-benefit and decision analysis, which generally focus on the estimation and evaluation of risks, benefits and costs, in a framework that balances these factors against each other. These analytical methods tend by their quantitative nature to emphasize the magnitude of risks, costs and alternatives, and to downplay other factors, especially those that are not easily expressed in quantitative terms, that affect acceptance or rejection of risk. Such other factors include the issues of risk perceptions and how and by whom risk decisions are made.

  10. External approach to rhinoplasty.

    Science.gov (United States)

    Goodman, Wilfred S; Charbonneau, Paul A

    2015-07-01

    The technique of external rhinoplasty is outlined. Having reviewed 74 cases, its advantages and disadvantages are discussed. Reluctance to use this external approach seems to be based on emotional rather than radical grounds, for its seems to be the procedure of choice for many problems.

  11. Comparing Information Access Approaches.

    Science.gov (United States)

    Chalmers, Matthew

    1999-01-01

    Presents a broad view of information access, drawing from philosophy and semiology in constructing a framework for comparative discussion that is used to examine the information representations that underlie four approaches to information access--information retrieval, workflow, collaborative filtering, and the path model. Contains 32 references.…

  12. Synopsis of emergent approaches

    Science.gov (United States)

    Malcolm North; Brandon Collins; John Keane; Jonathan W. Long; Carl Skinner; Bill. Zielinski

    2014-01-01

    This synopsis presents three integrated themes that emerged from synthesizing information about biological resources. These themes become particularly important when managing forests to promote resilience at large landscape scales and long timeframes. This synopsis summarizes ideas in the longer chapter 1.2, “Integrative Approaches: Promoting Socioecological Resilience...

  13. Implementation of Communicative Approach

    Science.gov (United States)

    Jabeen, Shazi Shah

    2014-01-01

    In the contemporary age of high professional requirements such as excellent communicative skills, the need for successful learning of communicative skills of English language suggests communicative ability to be the goal of language teaching. In other words, to teach English language using communicative approach becomes essential. Studies to…

  14. Islamic approach in counseling.

    Science.gov (United States)

    Hanin Hamjah, Salasiah; Mat Akhir, Noor Shakirah

    2014-02-01

    A religious approach is one of the matters emphasized in counseling today. Many researchers find that there is a need to apply the religious element in counseling because religion is important in a client's life. The purpose of this research is to identify aspects of the Islamic approach applied in counseling clients by counselors at Pusat Kaunseling Majlis Agama Islam Negeri Sembilan (PKMAINS). In addition, this research also analyses the Islamic approach applied in counseling at PKMAINS with reference to al-Quran and al-Sunnah. This is a qualitative research in the form of case study at PKMAINS. The main method used in this research is interview. The research instrument used is interview protocol. The respondents in this study include 9 counselors who serve in one of the counseling centers in Malaysia. This study also uses questionnaire as an additional instrument, distributed to 36 clients who receive counseling service at the center. The findings of the study show that the Islamic approach applied in counseling at PKMAINS may be categorized into three main aspects: aqidah (faith), ibadah (worship/ultimate devotion and love for God) and akhlaq (moral conduct). Findings also show that the counseling in these aspects is in line with Islamic teachings as contained in al-Quran and al-Sunnah.

  15. Ecosystem approach in education

    Science.gov (United States)

    Nabiullin, Iskander

    2017-04-01

    Environmental education is a base for sustainable development. Therefore, in our school we pay great attention to environmental education. Environmental education in our school is based on ecosystem approach. What is an ecosystem approach? Ecosystem is a fundamental concept of ecology. Living organisms and their non-living environments interact with each other as a system, and the biosphere planet functions as a global ecosystem. Therefore, it is necessary for children to understand relationships in ecosystems, and we have to develop systems thinking in our students. Ecosystem approach and systems thinking should help us to solve global environmental problems. How do we implement the ecosystem approach? Students must understand that our biosphere functions as a single ecosystem and even small changes can lead to environmental disasters. Even the disappearance of one plant or animal species can lead to irreversible consequences. So in the classroom we learn the importance of each living organism for the nature. We pay special attention to endangered species, which are listed in the Red Data List. Kids are doing projects about these organisms, make videos, print brochures and newspapers. Fieldwork also plays an important role for ecosystem approach. Every summer, we go out for expeditions to study species of plants and animals listed in the Red Data List of Tatarstan. In class, students often write essays on behalf of any endangered species of plants or animals, this also helps them to understand the importance of each living organism in nature. Each spring we organise a festival of environmental projects among students. Groups of 4-5 students work on a solution of environmental problems, such as water, air or soil pollution, waste recycling, the loss of biodiversity, etc. Participants shoot a clip about their project, print brochures. Furthermore, some of the students participate in national and international scientific Olympiads with their projects. In addition to

  16. Design, Synthesis and Characterization of Polyethylene-Based Macromolecular Architectures by Combining Polyhomologation with Powerful Linking Chemistry

    KAUST Repository

    Alkayal, Nazeeha

    2016-09-05

    -based graft terpolymers were synthesized via the “grafting onto” strategy by combining nitroxide-mediated radical polymerization (NMP), polyhomologation and copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC). Three steps were involved in this approach: (a) synthesis of alkyne-terminated polyethylene-b-poly(ε-caprolactone) (PE-b-PCL-alkyne) block copolymers (branches) by esterification of PE-b-PCL-OH with 4-pentynoic acid; the PE-b-PCL-OH was obtained by polyhomologation of dimethylsulfoxonium methylide to afford PE-OH, followed by ring opening polymerization of ε-caprolactone using PE-OH as a macroinitiator (b) synthesis of random copolymers of styrene (St) and 4-chloromethylstyrene (4-CMS) with various CMS contents, by nitroxide-mediated radical copolymerization (NMP), and conversion of chloride to azide groups by reaction with sodium azide (NaN3) (backbone) and (c) “click” linking reaction to afford the PE-based graft terpolymers. This method opens up new routes for the creation of polyethylene-based graft terpolymers by a combination of polyhomologation, NMP and CuAAC. The third project deals with the synthesis of polyethylene-based tadpole copolymer (c-PE)-b-PSt. Cyclic polymers represent a class of understudied polymer architecture mainly due to the synthetic challenges. Within this dissertation, a new method was reported for the synthesis of cyclic polymers in exceptionally high purity and yield. The main approaches to synthesize macrocycles are based on the end-to-end ring-closure (coupling) of homo difunctional linear precursors under high dilution. Our process relies on the preparation of well-defined linear α, ω-dihydroxy polyethylene and a bromide group at the middle of the chain through polyhomologation of ylide using functionalized initiator, followed by ATRP of styrene monomer. The two hydroxyl groups were transformed into alkyne groups, via esterification reaction, followed by Glaser reaction between terminal alkynes to afford the tadpole

  17. Synthesis of block copolymers by combination of atom transfer radical polymerization and visible light-induced free radical promoted cationic polymerization.

    Science.gov (United States)

    Kahveci, Muhammet U; Acik, Gokhan; Yagci, Yusuf

    2012-02-27

    A new synthetic approach for the preparation of block copolymers by mechanistic transformation from atom transfer radical polymerization (ATRP) to visible light-induced free radical promoted cationic polymerization is described. A series of halide end-functionalized polystyrenes with different molecular weights synthesized by ATRP were utilized as macro-coinitiators in dimanganese decacarbonyl [Mn(2) (CO)(10) ] mediated free radical promoted cationic photopolymerization of cyclohexene oxide or isobutyl vinyl ether. Precursor polymers and corresponding block copolymers were characterized by spectral, chromatographic, and thermal analyses. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Complex Macromolecular Architectures by Living Cationic Polymerization

    KAUST Repository

    Alghamdi, Reem D.

    2015-05-01

    Poly (vinyl ether)-based graft polymers have been synthesized by the combination of living cationic polymerization of vinyl ethers with other living or controlled/ living polymerization techniques (anionic and ATRP). The process involves the synthesis of well-defined homopolymers (PnBVE) and co/terpolymers [PnBVE-b-PCEVE-b-PSiDEGVE (ABC type) and PSiDEGVE-b-PnBVE-b-PSiDEGVE (CAC type)] by sequential living cationic polymerization of n-butyl vinyl ether (nBVE), 2-chloroethyl vinyl ether (CEVE) and tert-butyldimethylsilyl ethylene glycol vinyl ether (SiDEGVE), using mono-functional {[n-butoxyethyl acetate (nBEA)], [1-(2-chloroethoxy) ethyl acetate (CEEA)], [1-(2-(2-(t-butyldimethylsilyloxy)ethoxy) ethoxy) ethyl acetate (SiDEGEA)]} or di-functional [1,4-cyclohexanedimethanol di(1-ethyl acetate) (cHMDEA), (VEMOA)] initiators. The living cationic polymerizations of those monomers were conducted in hexane at -20 0C using Et3Al2Cl3 (catalyst) in the presence of 1 M AcOEt base.[1] The PCEVE segments of the synthesized block terpolymers were then used to react with living macroanions (PS-DPE-Li; poly styrene diphenyl ethylene lithium) to afford graft polymers. The quantitative desilylation of PSiDEGVE segments by n-Bu4N+F- in THF at 0 °C led to graft co- and terpolymers in which the polyalcohol is the outer block. These co-/terpolymers were subsequently subjected to “grafting-from” reactions by atom transfer radical polymerization (ATRP) of styrene to afford more complex macromolecular architectures. The base assisted living cationic polymerization of vinyl ethers were also used to synthesize well-defined α-hydroxyl polyvinylether (PnBVE-OH). The resulting polymers were then modified into an ATRP macro-initiator for the synthesis of well-defined block copolymers (PnBVE-b-PS). Bifunctional PnBVE with terminal malonate groups was also synthesized and used as a precursor for more complex architectures such as H-shaped block copolymer by “grafting-from” or

  19. Domain Approach: An Alternative Approach in Moral Education

    Science.gov (United States)

    Vengadasalam, Chander; Mamat, Wan Hasmah Wan; Mail, Fauziah; Sudramanian, Munimah

    2014-01-01

    This paper discusses the use of the domain approach in moral education in an upper secondary school in Malaysia. Moral Education needs a creative and an innovative approach. Therefore, a few forms of approaches are used in the teaching-learning of Moral Education. This research describes the use of domain approach which comprises the moral domain…

  20. Transaction based approach

    Science.gov (United States)

    Hunka, Frantisek; Matula, Jiri

    2017-07-01

    Transaction based approach is utilized in some methodologies in business process modeling. Essential parts of these transactions are human beings. The notion of agent or actor role is usually used for them. The paper on a particular example describes possibilities of Design Engineering Methodology for Organizations (DEMO) and Resource-Event-Agent (REA) methodology. Whereas the DEMO methodology can be regarded as a generic methodology having its foundation in the theory of Enterprise Ontology the REA methodology is regarded as the domain specific methodology and has its origin in accountancy systems. The results of these approaches is that the DEMO methodology captures everything that happens in the reality with a good empirical evidence whereas the REA methodology captures only changes connected with economic events. Economic events represent either change of the property rights to economic resource or consumption or production of economic resources. This results from the essence of economic events and their connection to economic resources.

  1. The Knowledge Governance Approach

    DEFF Research Database (Denmark)

    Foss, Nicolai J.

    An attempt is made to characterize a `knowledge governance approach' as a distinctive, emerging field that cuts across the fields of knowledge management, organisation studies, strategy and human resource management. Knowledge governance is taken up with how the deployment of administrative...... apparatus influences knowledge processes, such as sharing, retaining and creating knowledge. It insists on clear behavioural foundations, adopts an economizing perspective and examines efficient alignment between knowledge transactions with diverse characteristics and governance structures and mechanisms...... with diverse capabilities of handling these transactions. Various open research issues that a knowledge governance approach may illuminate are sketched. Although knowledge governance draws clear inspiration from organizational economics and `rational' organization theory, it recognizes that knowledge...

  2. Multidisciplinary Approach to Obesity

    Directory of Open Access Journals (Sweden)

    Berna Bulut Çakmak

    2014-12-01

    Full Text Available Obesity is a world wide public health problem which increases morbidity and mortality. A multidiciplinary approach is increasingly becoming important for treatment of obesity. Pharmacological agents, sergery, and cognitive behavioral terapy (CBT are the recommended treatment approaches. In this review, these treatment modalities are reviewed. In CBT of obesity, the dysfunctional thoughts and behaviors which prevent the person for losing weight or doing exercise opr which cause gaining back the lost weight are identified, and specific techniques to change these thoughts and behaviors are thought. It may be used as an individiual therapy, but it may also be more effective when used as a group psychotherapy. In this article, the CBT techniques used in obesity treatment are summarized. [JCBPR 2014; 3(3.000: 142-149

  3. Rail transport systems approach

    CERN Document Server

    2017-01-01

    This book shows how the systems approach is employed by scientists in various countries to solve specific problems concerning railway transport. In particular, the book describes the experiences of scientists from Romania, Germany, the Czech Republic, the UK, Russia, Ukraine, Lithuania and Poland. For many of these countries there is a problem with the historical differences between the railways. In particular, there are railways with different rail gauges, with different signaling and communication systems, with different energy supplies and, finally, with different political systems, which are reflected in the different approaches to the management of railway economies. The book’s content is divided into two main parts, the first of which provides a systematic analysis of individual means of providing and maintaining rail transport. In turn, the second part addresses infrastructure and management development, with particular attention to security issues. Though primarily written for professionals involved...

  4. A Personal Approach

    Directory of Open Access Journals (Sweden)

    Kellyn Weir

    2015-12-01

    Full Text Available This study explored the process of taking a personal approach to my son’s problems with computer games. As a psychology student, I should have been in a good position to explore the paradoxical emotions and this situation of conflict. Yet I was also aware that relating closely to the people we are studying has long been a taboo even in qualitative research. I nevertheless adopted a collaborative methodology in which I balanced a dual role of parent and researcher. Taking a personal approach, allowing intimate, reciprocal negotiation, I was not only able to put this taboo to the rare empirical test but also achieved an insight that would otherwise have not been available to me. By engaging in dialogue and encouraging the ability to object, a first-person plural (We, position was achieved in which an understanding of this situation developed and has transferred to our everyday lives.

  5. Dimensional Approach in Psychiatry

    Directory of Open Access Journals (Sweden)

    Osman Ozdemir

    2012-09-01

    Full Text Available In psychiatry there is a traditional categorical conception stating that several disorders like schizophrenia and bipolar disorder have distinct etiologies. On the other hand, dimensional approach claims that these entities are actually the same disorder reflecting different clinical aspects of same mental disorder in the course of time. ICD and DSM classifications are based on separate categories of different mental disorders. Howewer, it is quite difficult to consider a mental disorder as a discrete entity that has absolute boundaries from other disorders. There are patients manifesting symptoms of two or more categories but do not fulfill all diagnostic criteria for any mental disorder. Dimensional approach handles the psychopathology as a continuing process and establish the patients to the different ongoing points. According to this view, in fact, multiple diagnosis reflect dimensions of the same disease.

  6. Phase Field Approach

    Science.gov (United States)

    Koyama, Toshiyuki

    The term phase field has recently become known across many fields of materials science. The meaning of phase field is the spatial and temporal order parameter field defined in a continuum-diffused interface model. By using the phase field order parameters, many types of complex microstructure changes observed in materials science are described effectively. This methodology has been referred to as the phase field method, phase field simulation, phase field modeling, phase field approach, etc. In this chapter, the basic concept and theoretical background for the phase field approach is explained in Sects. 21.1 and 21.2. The overview of recent applications of the phase field method is demonstrated in Sects. 21.3 to 21.6.

  7. Microscopic approach to polaritons

    DEFF Research Database (Denmark)

    Skettrup, Torben

    1981-01-01

    The interaction between excitons and light has been investigated in detail. The perturbational approach turns out to be invalid. However, an exact solution can be obtained directly from the Schrödinger equation for a fixed light field. This solution corresponds to a nonlinear optical response...... contrary to experimental experience. In order to remove this absurdity the semiclassical approach must be abandoned and the electromagnetic field quantized. A simple microscopic polariton model is then derived. From this the wave function for the interacting exciton-photon complex is obtained...... of light of the crystal. The introduction of damping smears out the excitonic spectra. The wave function of the polariton, however, turns out to be very independent of damping up to large damping values. Finally, this simplified microscopic polariton model is compared with the exact solutions obtained...

  8. Thermodynamics an engineering approach

    CERN Document Server

    Cengel, Yunus A

    2014-01-01

    Thermodynamics, An Engineering Approach, eighth edition, covers the basic principles of thermodynamics while presenting a wealth of real-world engineering examples so students get a feel for how thermodynamics is applied in engineering practice. This text helps students develop an intuitive understanding by emphasizing the physics and physical arguments. Cengel and Boles explore the various facets of thermodynamics through careful explanations of concepts and use of numerous practical examples and figures, having students develop necessary skills to bridge the gap between knowledge and the confidence to properly apply their knowledge. McGraw-Hill is proud to offer Connect with the eighth edition of Cengel/Boles, Thermodynamics, An Engineering Approach. This innovative and powerful new system helps your students learn more efficiently and gives you the ability to assign homework problems simply and easily. Problems are graded automatically, and the results are recorded immediately. Track individual stude...

  9. An Approach to Cosmeceuticals.

    Science.gov (United States)

    Milam, Emily C; Rieder, Evan A

    2016-04-01

    The cosmeceutical industry is a multi-billion dollar, consumer-driven market. Products promise highly desirable anti-aging benefits, but are not subject to regulation. We present an introduction to cosmeceuticals for the general and cosmetic dermatologist, including definitions and explanations of key terms, an approach to the evidence base, a dissection of chamomile and green tea, two paradigmatic cosmeceutical products, and a window into the underlying psychology of this vast marketplace.

  10. Laparoscopic approach to hysterectomy

    OpenAIRE

    Nazik, Hakan

    2013-01-01

    Modern laparoscopic surgery is widely used throughout the world as it offers greater advantages than open procedures. The laparoscopic approach to hysterectomy has evolved over the last 20 years. Hysterectomies are performed abdominally, vaginally, laparoscopically or, more recently, with robotic assistance. Indications for a total laparoscopic hysterectomy are similar to those for total abdominal hysterectomy, and most commonly include uterine leiomyomata, pelvic organ prolapse, and a...

  11. Breakfast: a multidisciplinary approach

    OpenAIRE

    Affinita, Antonio; Catalani, Loredana; Cecchetto, Giovanna; De Lorenzo, Gianfranco; Dilillo, Dario; Donegani, Giorgio; Fransos, Lucia; Lucidi, Fabio; Mameli, Chiara; Manna, Elisa; Marconi, Paolo; Mele, Giuseppe; Minestroni, Laura; Montanari, Massimo; Morcellini, Mario

    2013-01-01

    Background The role of breakfast as an essential part of an healthy diet has been only recently promoted even if breakfast practices were known since the Middle Age. The growing scientific evidences on this topic are extremely sector-based nevertheless breakfast could be regarded from different point of views and from different expertises. This approach, that take into account history, sociology, anthropology, medicine, psychology and pedagogy, is useful to better understand the value of this...

  12. [Approaches to radial shaft].

    Science.gov (United States)

    Bartoníček, J; Naňka, O; Tuček, M

    2015-10-01

    In the clinical practice, radial shaft may be exposed via two approaches, namely the posterolateral Thompson and volar (anterior) Henry approaches. A feared complication of both of them is the injury to the deep branch of the radial nerve. No consensus has been reached, yet, as to which of the two approaches is more beneficial for the proximal half of radius. According to our anatomical studies and clinical experience, Thompson approach is safe only in fractures of the middle and distal thirds of the radial shaft, but highly risky in fractures of its proximal third. Henry approach may be used in any fracture of the radial shaft and provides a safe exposure of the entire lateral and anterior surfaces of the radius.The Henry approach has three phases. In the first phase, incision is made along the line connecting the biceps brachii tendon and the styloid process of radius. Care must be taken not to damage the lateral cutaneous nerve of forearm.In the second phase, fascia is incised and the brachioradialis identified by the typical transition from the muscle belly to tendon and the shape of the tendon. On the lateral side, the brachioradialis lines the space with the radial artery and veins and the superficial branch of the radial nerve running at its bottom. On the medial side, the space is defined by the pronator teres in the proximal part and the flexor carpi radialis in the distal part. The superficial branch of the radial nerve is retracted together with the brachioradialis laterally, and the radial artery medially.In the third phase, the attachment of the pronator teres is identified by its typical tendon in the middle of convexity of the lateral surface of the radial shaft. The proximal half of the radius must be exposed very carefully in order not to damage the deep branch of the radial nerve. Dissection starts at the insertion of the pronator teres and proceeds proximally along its lateral border in interval between this muscle and insertion of the supinator

  13. Peritonitis: laparoscopic approach

    Directory of Open Access Journals (Sweden)

    Agresta Ferdinando

    2006-03-01

    Full Text Available Abstract Background Laparoscopy has became as the preferred surgical approach to a number of different diseases because it allows a correct diagnosis and treatment at the same time. In abdominal emergencies, both components of treatment – exploration to identify the causative pathology and performance of an appropriate operation – can often be accomplished via laparoscopy. There is still a debate of peritonitis as a contraindication to this kind of approach. Aim of the present work is to illustrate retrospectively the results of a case-control experience of laparoscopic vs. open surgery for abdominal peritonitis emergencies carried out at our institution. Methods From January 1992 and January 2002 a total of 935 patients (mean age 42.3 ± 17.2 years underwent emergent and/or urgent surgery. Among them, 602 (64.3% were operated on laparoscopically (of whom 112 -18.7% – with peritonitis, according to the presence of a surgical team trained in laparoscopy. Patients with a history of malignancy, more than two previous major abdominal surgeries or massive bowel distension were not treated Laparoscopically. Peritonitis was not considered contraindication to Laparoscopy. Results The conversion rate was 23.2% in patients with peritonitis and was mainly due to the presence of dense intra-abdominal adhesions. Major complications ranged as high as 5.3% with a postoperative mortality of 1.7%. A definitive diagnosis was accomplished in 85.7% (96 pat. of cases, and 90.6% (87 of these patients were treated successfully by Laparoscopy. Conclusion Even if limited by its retrospective feature, the present experience let us to consider the Laparoscopic approach to abdominal peritonitis emergencies a safe and effective as conventional surgery, with a higher diagnostic yield and allows for lesser trauma and a more rapid postoperative recovery. Such features make Laparoscopy a challenging alternative to open surgery in the management algorithm for abdominal

  14. New Encrypted Steganography Approach

    Directory of Open Access Journals (Sweden)

    Saba Mohammed Husain‎

    2017-12-01

    Full Text Available The proposed research Provides an approach for hiding an encrypted text in side a digital image. Where the text is encrypted in a complex manner used method of PlayFair to encrypt clear text and to increase security put lettering ciphertext on the geometric shape clockwise and then we write the ciphertext output in the form of lines, taken new ciphertext and converted to Ascii code and then to binary and hidden text in bits least importance in the picture. The results were good by PNSR scale

  15. Experimental approaches and applications

    CERN Document Server

    Crasemann, Bernd

    1975-01-01

    Atomic Inner-Shell Processes, Volume II: Experimental Approaches and Applications focuses on the physics of atomic inner shells, with emphasis on experimental aspects including the use of radioactive atoms for studies of atomic transition probabilities. Surveys of modern techniques of electron and photon spectrometry are also presented, and selected practical applications of inner-shell processes are outlined. Comprised of six chapters, this volume begins with an overview of the general principles underlying the experimental techniques that make use of radioactive isotopes for inner-sh

  16. URBAN POLITICS: KEY APPROACHES

    Directory of Open Access Journals (Sweden)

    Ledyaeva Ol'ga Mikhaylovna

    2012-10-01

    Full Text Available Several approaches that underlie urban politics are discussed in the paper. They include neo-liberalism, political economy discourse, elitist/pluralist debates, and postmodernism. The neoliberal approach focuses on the limited role of the state and individual responsibility. The legal framework protects both the rights and responsibilities of individuals and regulates the operation of the market. It is the market that fosters individual choices and provides goods and services by virtue of the processes which are flexible, efficient and transparent. The political economy approaches (regulation theory, public choice theory, neo-Marxism explain urban politics via the analysis of national and international economic processes and changes in contemporary capitalism. Changes in national and international economies determine what solutions are possible. The discourse has been influenced by the debate on globalization of capital and labour markets. Modern elitism and neopluralism are represented by theories of "growth machines" and "urban regimes". The former focuses on bargaining alliances between political and business leaders in order to manage the urban system and to promote its growth. The latter develops neopluralist explanations of power within local communities with an emphasis on the fragmented nature of the government where local authorities lack comprehensive governing powers. Postmodernism views the city as the site of the crisis of late capitalism which leads to segregation of neighbourhoods onto prosperous areas and ghettoes. In contrast to the modern city, the postmodern city is not defined by its industrial base; rather, it is determined by its consumerist environment of malls and museums, characterized by revivalist architecture. At the same time, the suburban shopping mall and a motorway network make nonsense of the idea of the city as a unique and well-defined space. These and other approaches encompass a wide spectrum of possibilities

  17. Topology optimization approaches

    DEFF Research Database (Denmark)

    Sigmund, Ole; Maute, Kurt

    2013-01-01

    Topology optimization has undergone a tremendous development since its introduction in the seminal paper by Bendsøe and Kikuchi in 1988. By now, the concept is developing in many different directions, including “density”, “level set”, “topological derivative”, “phase field”, “evolutionary” and se......” and several others. The paper gives an overview, comparison and critical review of the different approaches, their strengths, weaknesses, similarities and dissimilarities and suggests guidelines for future research....

  18. The collaboratory approach

    Energy Technology Data Exchange (ETDEWEB)

    Peskin, A.M.

    1997-04-01

    A {open_quotes}collaboratory{close_quotes} has been defined as a center without walls, in which researchers can perform their work without regard to geographical location. To an increasing degree, engineering design and development is also taking the form of far-flung collaborations among divisions of a plant, subcontractors, university consultants and customers. It has long been recognized that quality engineering education presents the student with an environment that duplicates as much as possible that which the graduate will encounter in industry. To that end, it is important that engineering schools begin to introduce the collaboratory approach in its preparation, and even use it in delivery of subject matter to students.

  19. Towards a Tectonic Approach

    DEFF Research Database (Denmark)

    Hvejsel, Marie Frier; Kirkegaard, Poul Henning; Mortensen, Sophie Bondgaard

    2015-01-01

    through this transformation is inevitably a tectonic question. By analyzing three historical examples, Adolf Loos’ Villa Moller, Le Corbusier’s Unité d’Habitation, and Frank Lloyd Wright’s Johnson Wax Administration Building, chosen for their tectonic ability to exploit the technical ‘principle’ defining...... the building envelope as an aesthetic ‘gesture’, this paper discusses the architectural challenges related to energy renovation in a Danish context and tectonic design method as an approach to these challenges in everyday practice....

  20. Approaches for Stereo Matching

    Directory of Open Access Journals (Sweden)

    Takouhi Ozanian

    1995-04-01

    Full Text Available This review focuses on the last decade's development of the computational stereopsis for recovering three-dimensional information. The main components of the stereo analysis are exposed: image acquisition and camera modeling, feature selection, feature matching and disparity interpretation. A brief survey is given of the well known feature selection approaches and the estimation parameters for this selection are mentioned. The difficulties in identifying correspondent locations in the two images are explained. Methods as to how effectively to constrain the search for correct solution of the correspondence problem are discussed, as are strategies for the whole matching process. Reasons for the occurrence of matching errors are considered. Some recently proposed approaches, employing new ideas in the modeling of stereo matching in terms of energy minimization, are described. Acknowledging the importance of computation time for real-time applications, special attention is paid to parallelism as a way to achieve the required level of performance. The development of trinocular stereo analysis as an alternative to the conventional binocular one, is described. Finally a classification based on the test images for verification of the stereo matching algorithms, is supplied.

  1. Predictive ecology: systems approaches.

    Science.gov (United States)

    Evans, Matthew R; Norris, Ken J; Benton, Tim G

    2012-01-19

    The world is experiencing significant, largely anthropogenically induced, environmental change. This will impact on the biological world and we need to be able to forecast its effects. In order to produce such forecasts, ecology needs to become more predictive--to develop the ability to understand how ecological systems will behave in future, changed, conditions. Further development of process-based models is required to allow such predictions to be made. Critical to the development of such models will be achieving a balance between the brute-force approach that naively attempts to include everything, and over simplification that throws out important heterogeneities at various levels. Central to this will be the recognition that individuals are the elementary particles of all ecological systems. As such it will be necessary to understand the effect of evolution on ecological systems, particularly when exposed to environmental change. However, insights from evolutionary biology will help the development of models even when data may be sparse. Process-based models are more common, and are used for forecasting, in other disciplines, e.g. climatology and molecular systems biology. Tools and techniques developed in these endeavours can be appropriated into ecological modelling, but it will also be necessary to develop the science of ecoinformatics along with approaches specific to ecological problems. The impetus for this effort should come from the demand coming from society to understand the effects of environmental change on the world and what might be performed to mitigate or adapt to them.

  2. Breakfast: a multidisciplinary approach

    Science.gov (United States)

    2013-01-01

    Background The role of breakfast as an essential part of an healthy diet has been only recently promoted even if breakfast practices were known since the Middle Age. The growing scientific evidences on this topic are extremely sector-based nevertheless breakfast could be regarded from different point of views and from different expertises. This approach, that take into account history, sociology, anthropology, medicine, psychology and pedagogy, is useful to better understand the value of this meal in our culture. The aim of this paper was to analyse breakfast-related issues based on a multidisciplinary approach with input by specialists from different fields of learning. Discussion Breakfast is now recommended as part of a diet because it is associated with healthier macro- and micronutrient intakes, body mass index and lifestyle. Moreover recent studies showed that breakfast improves cognitive function, intuitive perception and academic performance. Research demonstrates the importance of providing breakfast not only to children but in adults and elderly too. Although the important role breakfast plays in maintaining the health, epidemiological data from industrialised countries reveal that many individuals either eat a nutritionally unhealthy breakfast or skip it completely. Summary The historical, bio-psychological and educational value of breakfast in our culture is extremely important and should be recognized and stressed by the scientific community. Efforts should be done to promote this practice for the individual health and well-being. PMID:23842429

  3. Modular Approach to Spintronics.

    Science.gov (United States)

    Camsari, Kerem Yunus; Ganguly, Samiran; Datta, Supriyo

    2015-06-11

    There has been enormous progress in the last two decades, effectively combining spintronics and magnetics into a powerful force that is shaping the field of memory devices. New materials and phenomena continue to be discovered at an impressive rate, providing an ever-increasing set of building blocks that could be exploited in designing transistor-like functional devices of the future. The objective of this paper is to provide a quantitative foundation for this building block approach, so that new discoveries can be integrated into functional device concepts, quickly analyzed and critically evaluated. Through careful benchmarking against available theory and experiment we establish a set of elemental modules representing diverse materials and phenomena. These elemental modules can be integrated seamlessly to model composite devices involving both spintronic and nanomagnetic phenomena. We envision the library of modules to evolve both by incorporating new modules and by improving existing modules as the field progresses. The primary contribution of this paper is to establish the ground rules or protocols for a modular approach that can build a lasting bridge between materials scientists and circuit designers in the field of spintronics and nanomagnetics.

  4. Comorbidity: a multidimensional approach.

    Science.gov (United States)

    Capobianco, Enrico; Lio', Pietro

    2013-09-01

    Comorbidity represents an extremely complex domain of research. An individual entity, the patient, is the center of gravity of a system characterized by multiple, complex, and interrelated conditions, disorders, or diseases. Such complexity is influenced by uncertainty that is difficult to decipher and is proportional to the number of associated morbidities. Computational scientists usually provide meta-analysis studies aimed at integrating various types of evidence, but in our opinion they may help reformulate comorbidity by emphasizing, in particular, two aspects: (i) a systems approach, which allows for an ensemble view of comorbidity, and offers a model representation generalizable to multimorbidity; and (ii) a dynamic network inference approach, which is indicated for the analysis of links among morbidities and evaluation of risk. Notably, the main question remains whether such instruments suggest a shift of paradigm providing prospective impact on medical practice. We have identified in the simultaneous consideration of multiple dimensions linked to comorbidity complexity the rationale for such translation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Engineering approaches to immunotherapy.

    Science.gov (United States)

    Swartz, Melody A; Hirosue, Sachiko; Hubbell, Jeffrey A

    2012-08-22

    As the science of immunology grows increasingly mechanistic, motivation for developing quantitative, design-based engineering approaches has also evolved, both for therapeutic interventions and for elucidating immunological pathways in human disease. This has seeded the nascent field of "immunoengineering," which seeks to apply engineering analyses and design approaches to problems in translational immunology. For example, cell engineers are creating ways to tailor and use immune cells as living therapeutics; protein engineers are devising new methods of rapid antibody discovery; biomaterials scientists are guiding vaccine delivery and immune-cell activation with novel constructs; and systems immunologists are deciphering the evolution and maintenance of T and B cell receptor repertoires, which could help guide vaccine design. The field is multidisciplinary and collaborative, with engineers and immunologists working together to better understand and treat disease. We discuss the scientific progress in this young, yet rapidly evolving research area, which has yielded numerous start-up companies that are betting on impact in clinical and commercial translation in the near future.

  6. Breakfast: a multidisciplinary approach.

    Science.gov (United States)

    Affinita, Antonio; Catalani, Loredana; Cecchetto, Giovanna; De Lorenzo, Gianfranco; Dilillo, Dario; Donegani, Giorgio; Fransos, Lucia; Lucidi, Fabio; Mameli, Chiara; Manna, Elisa; Marconi, Paolo; Mele, Giuseppe; Minestroni, Laura; Montanari, Massimo; Morcellini, Mario; Rovera, Giuseppe; Rotilio, Giuseppe; Sachet, Marco; Zuccotti, Gian Vincenzo

    2013-07-10

    The role of breakfast as an essential part of an healthy diet has been only recently promoted even if breakfast practices were known since the Middle Age. The growing scientific evidences on this topic are extremely sector-based nevertheless breakfast could be regarded from different point of views and from different expertises. This approach, that take into account history, sociology, anthropology, medicine, psychology and pedagogy, is useful to better understand the value of this meal in our culture. The aim of this paper was to analyse breakfast-related issues based on a multidisciplinary approach with input by specialists from different fields of learning. Breakfast is now recommended as part of a diet because it is associated with healthier macro- and micronutrient intakes, body mass index and lifestyle. Moreover recent studies showed that breakfast improves cognitive function, intuitive perception and academic performance. Research demonstrates the importance of providing breakfast not only to children but in adults and elderly too. Although the important role breakfast plays in maintaining the health, epidemiological data from industrialised countries reveal that many individuals either eat a nutritionally unhealthy breakfast or skip it completely. The historical, bio-psychological and educational value of breakfast in our culture is extremely important and should be recognized and stressed by the scientific community. Efforts should be done to promote this practice for the individual health and well-being.

  7. Generic Top-Functionalization of Patterned Antifouling Zwitterionic Polymers on Indium Tin Oxide

    NARCIS (Netherlands)

    Li, Y.; Giesbers, M.; Zuilhof, H.

    2012-01-01

    This paper presents a novel surface engineering approach that combines photochemical grafting and surface-initiated atom transfer radical polymerization (SI-ATRP) to attach zwitterionic polymer brushes onto indium tin oxide (ITO) substrates. The photochemically grafted hydroxyl-terminated organic

  8. Management practice: phenomenological approach

    Directory of Open Access Journals (Sweden)

    Myriam Siqueira da Cunha

    2005-01-01

    Full Text Available This work has the aim of understanding the lived experiences by managers in relation to organizational changes in an enterprise in the food area, located in the State of Rio Grande do Sul, Brazil. The role of managers has been constantly evaluated and their capacity of continuous learning and also the ability of transforming the learning in good organizational results is reacquired every instant. In this work, my intention is to show, using an interpretative analysis, real and practical situations, from lived experiences. The methodological way followed was the hermeneutic phenomenological approach, trying to give a global and a contextual treatment to the theme. The results achieved offer subsides for a new look over the management practice and point out the importance of the study of what is lived, as an inspiration source for the strategic decisions in the enterprises.

  9. Slurry pipeline design approach

    Energy Technology Data Exchange (ETDEWEB)

    Betinol, Roy; Navarro R, Luis [Brass Chile S.A., Santiago (Chile)

    2009-12-19

    Compared to other engineering technologies, the design of a commercial long distance Slurry Pipeline design is a relatively new engineering concept which gained more recognition in the mid 1960 's. Slurry pipeline was first introduced to reduce cost in transporting coal to power generating units. Since then this technology has caught-up worldwide to transport other minerals such as limestone, copper, zinc and iron. In South America, the use of pipeline is commonly practiced in the transport of Copper (Chile, Peru and Argentina), Iron (Chile and Brazil), Zinc (Peru) and Bauxite (Brazil). As more mining operations expand and new mine facilities are opened, the design of the long distance slurry pipeline will continuously present a commercially viable option. The intent of this paper is to present the design process and discuss any new techniques and approach used today to ensure a better, safer and economical slurry pipeline. (author)

  10. Towards a Dual Approach

    DEFF Research Database (Denmark)

    Holli, Anne Maria; Harder, Mette Marie Stæhr

    2016-01-01

    countries acknowledged as forerunners in gender equality, which also have ‘fairly strong’ parliamentary standing committees. The results show that both committees on gender equality can be regarded as ‘feminist’ in character and both interact with relevant civil society organisations. Their impact......Drawing on insights from state feminism and legislative studies on parliamentary committees, this article develops a dual approach for the comparative analysis of committees on gender equality. Empirically, it compares the standing committees on gender equality in Denmark and Finland, two Nordic...... as measured by legislative outputs and oversight differs, however, in line with differing committee system characteristics: the Finnish committee has more impact on legislative outputs while the Danish committee has more impact on overseeing government....

  11. Globalization - Different approaches

    Directory of Open Access Journals (Sweden)

    Viorica Puscaciu

    2014-11-01

    Full Text Available In this paper we investigate the different approaches of the globalization phenomenon. Despite the geographical distancesm, the link between people are ever more strong on different ways and plans: from technology between political, economical, cultural world events, and many other aspects. So, the link between globalization and democracy, and its impact on the most important social and economic matters. We also surprise the impact of the internet revolution and its corolar e-commerce, and its consequences, sometimes unpredictible ones. Another annalysed problem is that of the governments trying, and sometimes succeeding to controll the money, products, peole and their ideas that freely move inside the national frontiers, thus going to slower or to stop the progress. Nevertheless, this global interraction between people also create phenomena of insecurity on different ways: terrorism, traffic of arms, drugs, economical aggresions causing the environment, and other inconvenient facts and situations.

  12. Bioengineering a conceptual approach

    CERN Document Server

    Pavlovic, Mirjana

    2015-01-01

    This book explores critical principles and new concepts in bioengineering, integrating the biological, physical and chemical laws and principles that provide a foundation for the field. Both biological and engineering perspectives are included, with key topics such as the physical-chemical properties of cells, tissues and organs; principles of molecules; composition and interplay in physiological scenarios; and the complex physiological functions of heart, neuronal cells, muscle cells and tissues. Chapters evaluate the emerging fields of nanotechnology, drug delivery concepts, biomaterials, and regenerative therapy. The leading individuals and events are introduced along with their critical research. Bioengineering: A Conceptual Approach is a valuable resource for professionals or researchers interested in understanding the central elements of bioengineering. Advanced-level students in biomedical engineering and computer science will also find this book valuable as a secondary textbook or reference.

  13. Integration a functional approach

    CERN Document Server

    Bichteler, Klaus

    1998-01-01

    This book covers Lebesgue integration and its generalizations from Daniell's point of view, modified by the use of seminorms. Integrating functions rather than measuring sets is posited as the main purpose of measure theory. From this point of view Lebesgue's integral can be had as a rather straightforward, even simplistic, extension of Riemann's integral; and its aims, definitions, and procedures can be motivated at an elementary level. The notion of measurability, for example, is suggested by Littlewood's observations rather than being conveyed authoritatively through definitions of (sigma)-algebras and good-cut-conditions, the latter of which are hard to justify and thus appear mysterious, even nettlesome, to the beginner. The approach taken provides the additional benefit of cutting the labor in half. The use of seminorms, ubiquitous in modern analysis, speeds things up even further. The book is intended for the reader who has some experience with proofs, a beginning graduate student for example. It might...

  14. Life History Approach

    DEFF Research Database (Denmark)

    Olesen, Henning Salling

    2015-01-01

    of the social and the psychic, both in the interpretation procedure and in some main theoretical understandings of language, body and mind. My article will present the reflections on the use of life history based methodology in learning and education research as a kind of learning story of research work.......The article presents a development of biographical research in education and learning research, in which psycho-societal interpretations play a key role. The horizon of the approach is the lifelong subjective engagement in intended as well as unintended learning, in formal education as well...... as in everyday life. Life histories represent lived lives past, present and anticipated future. As such they are interpretations of individuals’ experiences of the way in which societal dynamics take place in the individual body and mind, either by the individual him/herself or by another biographer. The Life...

  15. Cognitive approaches to emotions.

    Science.gov (United States)

    Oatley, Keith; Johnson-Laird, P N

    2014-03-01

    Cognitive approaches offer clear links between how emotions are thought about in everyday life and how they are investigated psychologically. Cognitive researchers have focused on how emotions are caused when events or other people affect concerns and on how emotions influence processes such as reasoning, memory, and attention. Three representative cognitive theories of emotion continue to develop productively: the action-readiness theory, the core-affect theory, and the communicative theory. Some principles are common to them and divergences can be resolved by future research. Recent explanations have included how emotions structure social relationships, how they function in psychological illnesses, and how they are central to music and fiction. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Laparoscopic approach to hysterectomy

    Directory of Open Access Journals (Sweden)

    Hakan Nazik

    2013-04-01

    Full Text Available Modern laparoscopic surgery is widely used throughout the world as it offers greater advantages than open procedures. The laparoscopic approach to hysterectomy has evolved over the last 20 years. Hysterectomies are performed abdominally, vaginally, laparoscopically or, more recently, with robotic assistance. Indications for a total laparoscopic hysterectomy are similar to those for total abdominal hysterectomy, and most commonly include uterine leiomyomata, pelvic organ prolapse, and abnormal uterine bleeding. When hysterectomy is going to be performed, the surgeon should decide which method is safer and more cost-effective. This paper aims to make a review of the indications, techniques and advantages of laparoscopic hysterectomy as well as the criteria to be used for appropriate patient selection.

  17. The Tripod Approach

    DEFF Research Database (Denmark)

    Bang, Anne Louise

    2012-01-01

    -and-break decision for a company. However textile design research has shown that experience of emotional value is closely connected to fabric perception, and much literature suggests that textiles are experienced by a combination of sensory evaluation and memory associations. This paper introduces the Tripod......The term ‘next to my skin’ is frequently used as a way to describe the close bonds between human beings and textiles. It is also widely accepted within the broad field of textile professionals that textile attributes related to emotional value – for example hand, look and drape – can be a make...... Approach as a framework that can support designing the stimuli, which can lead to personal experiences of emotional value in relation to applied textiles. It can be used to access the relevant level of entry in the textile design process focusing on appropriate design parameters, and support designing...

  18. Investigational approaches for mesothelioma

    Directory of Open Access Journals (Sweden)

    Veerle F Surmont

    2011-08-01

    Full Text Available MPM is a rare, aggressive tumour with a poor prognosis. In view of the poor survival benefit from first-line chemotherapy and the lack of subsequent effective treatment options, there is a strong need for the development of more effective treatment approaches for patients with MPM. This review will provide a comprehensive state of the art of new investigational approaches for mesothelioma. In an introductory section, the aetiology, epidemiology, natural history and standard of care treatment for MPM will be discussed. This review provide an update of the major clinical trials that impact mesothelioma treatment, discuss the impact of novel therapeutics and provide perspective on where the clinical research in mesothelioma is moving.The evidence was collected by a systematic analysis of the literature (2000–2011 using the databases Medline (National Library of Medicine, USA, Embase (Elsevier, Netherlands, Cochrane Library (Great Britain, National Guideline Clearinghouse (USA, HTA Database (International Network of Agencies for Health Technology Assessment – INAHTA, NIH database (USA, International Pleural Mesothelioma Program – WHOLIS (WHO Database , with the following keywords and filters: mesothelioma, guidelines, treatment, surgery, chemotherapy, radiotherapy, review, investigational, drugsCurrently different targeted therapies and biologicals are under investigation for MPM. It is important that the molecular biologic research should first focus on mesothelioma-specific pathways and biomarkers in order to have more effective treatment options for this disease. The use of array technology will be certainly an implicit gain in the identification of new potential prognostic or biomarkers or important pathways in the MPM pathogenesis. Probably a central mesothelioma virtual tissue bank may contribute to the ultimate goal to identify druggable targets and to develop personalized treatment for the MPM patients.

  19. Standard Approaches to the Acetabulum Part 2: Ilioinguinal Approach.

    Science.gov (United States)

    Gänsslen, A; Grechenig, S T; Nerlich, M; Müller, M; Grechenig, W

    2016-01-01

    The ilioinguinal approach is one of the standard approaches in the treatment of displaced acetabular fractures used during the last decades (9). The meta-analysis of Giannoudis et al. showed that 21.9% of acetabular fractures were historically treated using this approach (3). One of the disadvantages of this study was, that studies focussing especially on posterior wall stabilization and studies dealing with more complex fracture types treated by extended approaches were integrated. Thus, these fracture types were overrepresented. Re-analysis excluding these data lead to an increase of the rate of anterior approaches to 25.9%. More recent data (years 2005-2007) from the German multicenter study showed that presently in almost 45% of the cases the single ilioinguinal approach was used and only 38% of patients were stabilized via the KocherLangenbeck approach (11). Historically, the Smith-Peterson approach (15, 17) and the iliofemoral approach were used to treat acetabular fractures. In the 60ies, based on the work by Letournel and Judet, the ilioinguinal approach was developed for acetabular fracture fixation (9). It is an extrapelvic approach resulting in an indirect reconstruction concept of the acetabulum without direct visualization of the articular acetabulum. The ilioinguinal approach was the standard anterior approach during the last 30-40 years. An important advantage is the reduced soft tissue detachment of periarticular muscles with only a small risk of developing heterotopic bone formation. The aim of the second part of "Standard approaches to the acetabulum" is to report on the special topics indication, positioning, exposure, incision, dissection, the anatomical basis of osteosynthesis and present results using ilioinguinal approach.

  20. Structural Sustainability - Heuristic Approach

    Science.gov (United States)

    Rostański, Krzysztof

    2017-10-01

    Nowadays, we are faced with a challenge of having to join building structures with elements of nature, which seems to be the paradigm of modern planning and design. The questions arise, however, with reference to the following categories: the leading idea, the relation between elements of nature and buildings, the features of a structure combining such elements and, finally, our perception of this structure. If we consider both the overwhelming globalization and our attempts to preserve local values, the only reasonable solution is to develop naturalistic greenery. It can add its uniqueness to any building and to any developed area. Our holistic model, presented in this paper, contains the above mentioned categories within the scope of naturalism. The model is divided into principles, actions related, and possible effects to be obtained. It provides a useful tool for determining the ways and priorities of our design. Although it is not possible to consider all possible actions and solutions in order to support sustainability in any particular design, we can choose, however, a proper mode for our design according to the local conditions by turning to the heuristic method, which helps to choose priorities and targets. Our approach is an attempt to follow the ways of nature as in the natural environment it is optimal solutions that appear and survive, idealism being the domain of mankind only. We try to describe various natural processes in a manner comprehensible to us, which is always a generalization. Such definitions, however, called artificial by naturalists, are presented as art or the current state of knowledge by artists and engineers. Reality, in fact, is always more complicated than its definitions. The heuristic method demonstrates the way how to optimize our design. It requires that all possible information about the local environment should be gathered, as the more is known, the fewer mistakes are made. Following the unquestionable principles, we can

  1. Halitosis: the multidisciplinary approach.

    Science.gov (United States)

    Bollen, Curd M L; Beikler, Thomas

    2012-06-01

    Halitosis, bad breath or oral malodour are all synonyms for the same pathology. Halitosis has a large social and economic impact. For the majority of patients suffering from bad breath, it causes embarrassment and affects their social communication and life. Moreover,halitosis can be indicative of underlying diseases. Only a limited number of scientific publications were presented in this field until 1995. Ever since, a large amount of research is published, often with lack of evidence. In general, intraoral conditions, like insufficient dental hygiene, periodontitis or tongue coating are considered to be the most important cause (85%) for halitosis. Therefore, dentists and periodontologists are the first-line professionals to be confronted with this problem. They should be well aware of the origin, the detection and especially of the treatment of this pathology. In addition, ear-nose-throat-associated (10%) or gastrointestinal/endocrinological (5%) disorders may contribute to the problem. In the case of halitophobia, psychiatrical or psychological problems may be present. Bad breath needs a multidisciplinary team approach: dentists, periodontologists, specialists in family medicine, ear-nose-throat surgeons, internal medicine and psychiatry need to be updated in this field, which still is surrounded by a large taboo.Multidisciplinary bad breath clinics offer the best environment to examine and treat this pathology that affects around 25% of the whole population. This article describes the origin, detection and treatment of halitosis, regarded from the different etiological origins.

  2. Combinatorial approach to modularity.

    Science.gov (United States)

    Radicchi, Filippo; Lancichinetti, Andrea; Ramasco, José J

    2010-08-01

    Communities are clusters of nodes with a higher than average density of internal connections. Their detection is of great relevance to better understand the structure and hierarchies present in a network. Modularity has become a standard tool in the area of community detection, providing at the same time a way to evaluate partitions and, by maximizing it, a method to find communities. In this work, we study the modularity from a combinatorial point of view. Our analysis (as the modularity definition) relies on the use of the configurational model, a technique that given a graph produces a series of randomized copies keeping the degree sequence invariant. We develop an approach that enumerates the null model partitions and can be used to calculate the probability distribution function of the modularity. Our theory allows for a deep inquiry of several interesting features characterizing modularity such as its resolution limit and the statistics of the partitions that maximize it. Additionally, the study of the probability of extremes of the modularity in the random graph partitions opens the way for a definition of the statistical significance of network partitions.

  3. Approaching Moisture Recycling Governance

    Science.gov (United States)

    Keys, Patrick; Wang-Erlandsson, Lan; Gordon, Line; Galaz, Victor; Ebbesson, Jonas

    2017-04-01

    The spatial and temporal dynamics of water resources are a continuous challenge for effective and sustainable national and international governance. Despite the surface watershed being the typical unit of water management, recent advances in hydrology have revealed 'atmospheric watersheds' - otherwise known as precipitationsheds. Also, recent research has demonstrated that water flowing within a precipitationshed may be modified by land-use change in one location, while the effect of this modification could be felt in a different province, nation, or continent. Notwithstanding these insights, the major legal and institutional implications of modifying moisture recycling have remained unexplored. In this presentation, we examine potential approaches to moisture recycling governance. We first identify a set of international study regions, and then develop a typology of moisture recycling relationships within these regions ranging from bilateral moisture exchange to more complex networks. This enables us to classify different types of legal and institutional governance principles. Likewise, we relate the moisture recycling types to existing land and water governance frameworks and management practices. The complexity of moisture recycling means institutional fit will be difficult to generalize for all moisture recycling relationships, but our typology allows the identification of characteristics that make effective governance of these normally ignored water flows more tenable.

  4. Exploring the integrated approach.

    Science.gov (United States)

    1979-01-01

    The integration of family planning with maternal and child health and nutrition has been implemented in India, but integration with developmental activities like community development involves the linking up of several different disciplines. Current trends of the integrated approach to family planning in the ESCAP countries are discussed by administrators from Bangkok, Manilla, Bangalore, Islamabad, and Trivandrum, India. IPPF experience in the nongovernmental sector found that to succeed, projects must be clearly described, realistic, and capable of evaluation. Development programs can be integrated with family planning programs as well as family planning/population education programs can be integrated with development projects. Possible areas of integration are income-generating skills/services; training programs; nutrition and health (home extension services); environmental sanitation and personal hygiene; water supply, tube wells; water management, conservation; and, utilization of agricultural by-products. The message of family planning can be effectively communciated through community organizations. In the Philippines, services which could be transferred to the field were transferred to volunteers in the barangays (neighborhoods) who worked on other projects, e.g. cooperatives, nutrition. All forum participants agreed that integration is a very good concept, but practising it is a complex reality.

  5. APPROACHES TO PUBLIC INTEGRITY

    Directory of Open Access Journals (Sweden)

    Simona-Roxana ULMAN

    2015-08-01

    Full Text Available Both concepts, integrity and public integrity, are always asked qualities in the social and economic environment, but they are never well defined. In this context, finding precise definitions and offering an ample explanation of the concepts are desired and useful for both economic theoretical and practical levels and become the aim of the present paper. Without a good understanding of a concept, no one is capable to attain it. In this context, it is impossible to ask for a public sector of integrity if both public actors and the citizens do not know what it really means. Therefore, the public actors first have to understand what integrity really supposes, and, then, to be capable to respect its principles. Taking into consideration the effects of public integrity or, on its opposite, of the divergence from it, especially represented by the phenomenon of corruption, on the economy at the macro, but also, on the micro level, public integrity in itself becomes a real economic problem that is aimed to be extensively analyzed through our interdisciplinary approach.

  6. Approaches to refractory epilepsy

    Directory of Open Access Journals (Sweden)

    Jerome Engel

    2014-01-01

    Full Text Available Epilepsy is one of the most common serious neurological conditions, and 30 to 40% of people with epilepsy have seizures that are not controlled by medication. Patients are considered to have refractory epilepsy if disabling seizures continue despite appropriate trials of two antiseizure drugs, either alone or in combination. At this point, patients should be referred to multidisciplinary epilepsy centers that perform specialized diagnostic testing to first determine whether they are, in fact, pharmacoresistant, and then, if so, offer alternative treatments. Apparent pharmacoresistance can result from a variety of situations, including noncompliance, seizures that are not epileptic, misdiagnosis of the seizure type or epilepsy syndrome, inappropriate use of medication, and lifestyle issues. For patients who are pharmacoresistant, surgical treatment offers the best opportunity for complete freedom from seizures. Surgically remediable epilepsy syndromes have been identified, but patients with more complicated epilepsy can also benefit from surgical treatment and require more specialized evaluation, including intracranial EEG monitoring. For patients who are not surgical candidates, or who are unwilling to consider surgery, a variety of other alternative treatments can be considered, including peripheral or central neurostimulation, ketogenic diet, and complementary and alternative approaches. When such alternative treatments are not appropriate or effective, quality of life can still be greatly improved by the psychological and social support services offered by multidisciplinary epilepsy centers. A major obstacle remains the fact that only a small proportion of patients with refractory epilepsy are referred for expert evaluation and treatment.

  7. Approaches to adenomyomectomy

    Directory of Open Access Journals (Sweden)

    Serene Thain

    2015-08-01

    Full Text Available Adenomyosis is a common gynecological condition that affects women, causing menstrual disturbances, pain, and subfertility. Adenomyomectomy as an alternative to hysterectomy has been widely performed in those who have not completed childbearing or those refusing a hysterectomy for a variety of reasons. Whichever the surgical route, the challenges of adenomyomectomy include possible misdiagnosis, defining the extent of resection, technical difficulties, dealing with the associated complications, and managing the risks of uterine rupture during a subsequent pregnancy. The principles of surgery mimic those of myomectomy, but the evolution of adenomyomectomy has been relatively unexciting with a general paucity of published data to date. Laparoscopic techniques have proven feasible generally, avoiding the risks of open surgery while conferring the benefits of microsurgery. Limitations in tactile feedback and access constraints have been the main drawbacks via this route. Meticulous stitching and repair is still of paramount importance in these operations. Preoperative gonadotropin-releasing hormone agonists have proven effective in shrinking the disease and reducing blood loss during surgery, whereas the postoperative use has resulted in a dramatic reduction in symptoms. Uterine artery ligation techniques have also been shown to be useful adjuncts, although we still need to be mindful of the potential effects in those desiring fertility. Furthermore, there is still no foolproof way in predicting those at risk of uterine rupture after adenomyomectomy. Hence, a nonprescriptive approach in managing adenomyomas is advised, where proper patient selection and counseling are important.

  8. Combinatorial approach to modularity

    Science.gov (United States)

    Radicchi, Filippo; Lancichinetti, Andrea; Ramasco, José J.

    2010-08-01

    Communities are clusters of nodes with a higher than average density of internal connections. Their detection is of great relevance to better understand the structure and hierarchies present in a network. Modularity has become a standard tool in the area of community detection, providing at the same time a way to evaluate partitions and, by maximizing it, a method to find communities. In this work, we study the modularity from a combinatorial point of view. Our analysis (as the modularity definition) relies on the use of the configurational model, a technique that given a graph produces a series of randomized copies keeping the degree sequence invariant. We develop an approach that enumerates the null model partitions and can be used to calculate the probability distribution function of the modularity. Our theory allows for a deep inquiry of several interesting features characterizing modularity such as its resolution limit and the statistics of the partitions that maximize it. Additionally, the study of the probability of extremes of the modularity in the random graph partitions opens the way for a definition of the statistical significance of network partitions.

  9. Exploring Mouse Protein Function via Multiple Approaches

    National Research Council Canada - National Science Library

    Huang, Guohua; Chu, Chen; Huang, Tao; Kong, Xiangyin; Zhang, Yunhua; Zhang, Ning; Cai, Yu-Dong

    2016-01-01

    .... In this study, we presented a novel approach to predict mouse protein functions. The approach was a sequential combination of a similarity-based approach, an interaction-based approach and a pseudo amino acid composition-based approach...

  10. Intermodal service - system approach

    Directory of Open Access Journals (Sweden)

    Mirosław Antonowicz

    2015-09-01

    Full Text Available   Introduction: Transportation services may be described in systemic categories. Intermodal freight transport is a practical expression of the system approach to transport. Development of the intermodal transport system has brought about the need for the comprehensive grasp of transportation processes. Intermodal transport operators manage the whole transportation service organization process. Hence, a question arises whether the service offered by an intermodal transport operator may be interpreted as a complex system service. Systemness of contemporary products and services consists in that their value for clients is predefined by their place in the whole system of products and/or services as well as by the network of their users. The network language, occurring in this paper, is connected with the development of the notion of network, one of the inspiring ideas in organization and management science of the recent years. Methods: Literature on the intermodal freight transport issue has been analysed by the present author for the purposes of this paper, with a view to the developing idea of marketing of system products. Within the adopted interpretative paradigm, qualitative / quantitative research was used. Case study is used, among others, to interpret a particular situation, in a way that the subsequent description appears as the research result and may be recognized as valuable contribution to the existent knowledge. The aim of the paper is to highlight, following the research results, the necessity to treat the service offered by intermodal transport operators in system categories. Such systemic interpretation points both to the multitude of components of the service and to the arising opportunity for comprehensive solution of the clients' needs and expectations. Results: The outcomes reveal that the service offered by an intermodal transport operator may be recognized as the complex systemic intermodal service. They contribute to the

  11. Diagnostic approach to diplopia.

    Science.gov (United States)

    Dinkin, Marc

    2014-08-01

    This article offers a pragmatic roadmap to the practicing neurologist on how to approach the patient with double vision. Strategies of history taking and examination techniques are reviewed, followed by a broad overview of the causes of diplopia organized by neuroanatomic localization. Diplopia may be the first symptom of serious vision or life-threatening neurologic disease, and its correct localization and diagnosis are therefore essential. The systems responsible for ocular movement and alignment in the vertical and horizontal plane include complex supranuclear circuitry, brainstem nuclei, cranial nerves III, IV, and VI, and their respective neuromuscular junctions and target muscles. Disruption at any point within this system or within the vestibular afferents that govern eye movement in response to head movements may therefore produce diplopia, leading to a broad differential diagnosis for the patient with diplopia. With a careful history and examination, the neurologist should be able to observe the patterns of diplopia that reveal the site of dysfunction, thus generating a shorter localization-specific list of possible etiologies. Examination of ocular motility including smooth pursuit and saccadic function, followed, if necessary, by testing designed to uncover misalignments of the eyes, including cover and Maddox rod testing, are primary components of the efferent neurologic examination. Further testing designed to detect myasthenia (eg, lid testing and fatigable upgaze) and orbital disease (eg, measuring proptosis, testing for resistance to retropulsion) may be necessary. Recent advances in the diagnosis of diplopia include the observation that vertical diplopia from skew deviation is more likely to improve with supine positioning than that caused by trochlear nerve palsies. Advances in the field of ocular myasthenia include the observation of decreased conversion to the generalized form with treatment with either steroids or thymectomy, although these

  12. The narrative approach to personalisation

    Science.gov (United States)

    Conlan, Owen; Staikopoulos, Athanasios; Hampson, Cormac; Lawless, Séamus; O'keeffe, Ian

    2013-06-01

    This article describes the narrative approach to personalisation. This novel approach to the generation of personalised adaptive hypermedia experiences employs runtime reconciliation between a personalisation strategy and a number of contextual models (e.g. user and domain). The approach also advocates the late binding of suitable content and services to the generated personalised pathway resulting in an interactive composition that comprises services as well as content. This article provides a detailed definition of the narrative approach to personalisation and showcases the approach through the examination of two use-cases: the personalised digital educational games developed by the ELEKTRA and 80Days projects; and the personalised learning activities realised as part of the AMAS project. These use-cases highlight the general applicability of the narrative approach and how it has been applied to create a diverse range of real-world systems.

  13. New Approaches to Final Cooling

    Energy Technology Data Exchange (ETDEWEB)

    Neuffer, David [Fermilab

    2014-11-10

    A high-energy muon collider scenario require a “final cooling” system that reduces transverse emittances by a factor of ~10 while allowing longitudinal emittance increase. The baseline approach has low-energy transverse cooling within high-field solenoids, with strong longitudinal heating. This approach and its recent simulation are discussed. Alternative approaches which more explicitly include emittance exchange are also presented. Round-to-flat beam transform, transverse slicing, and longitudinal bunch coalescence are possible components of the alternative approach. A more explicit understanding of solenoidal cooling beam dynamics is introduced.

  14. Simplified Approach to Inspection Planning

    DEFF Research Database (Denmark)

    Bloch, Allan; Sørensen, John Dalsgaard; Faber, Michael Havbro

    2000-01-01

    structural details and thereby develop pre-made inspection plans in tables which depend on relative cost of inspections, repairs and failures. Due to the simplicity of the format of the developed inspection plans the proposed approach has a high potential in code making for the design and maintenance......A simplified and practically applicable approach for risk based inspection planning of fatigue sensitive structural details is presented. The basic idea behind the approach is that the fatigue sensitive details are categorized according to their stress intensity factors and their design fatigue...... of steel structures. The validity of the proposed approach is illustrated through a study regarding inspection planning of offshore structures....

  15. Microbial Burden Approach : New Monitoring Approach for Measuring Microbial Burden

    Science.gov (United States)

    Venkateswaran, Kasthuri; Vaishampayan, Parag; Barmatz, Martin

    2013-01-01

    Advantages of new approach for differentiating live cells/ spores from dead cells/spores. Four examples of Salmonella outbreaks leading to costly destruction of dairy products. List of possible collaboration activities between JPL and other industries (for future discussion). Limitations of traditional microbial monitoring approaches. Introduction to new approach for rapid measurement of viable (live) bacterial cells/spores and its areas of application. Detailed example for determining live spores using new approach (similar procedure for determining live cells). JPL has developed a patented approach for measuring amount of live and dead cells/spores. This novel "molecular" method takes less than 5 to 7 hrs. compared to the seven days required using conventional techniques. Conventional "molecular" techniques can not discriminate live cells/spores among dead cells/spores. The JPL-developed novel method eliminates false positive results obtained from conventional "molecular" techniques that lead to unnecessary delay in the processing and to unnecessary destruction of food products.

  16. DEMOCRATIC APPROACHES TO ENVIRONMENTAL EDUCATION ...

    African Journals Online (AJOL)

    DREAM OR POSSIBILITY? Jo-Anne Ferreira. Research indicates that few teachers are currently using a democratic approach to teaching in environmental education even though much of the environmental education literature supports and encourages such an approach. Various explanations are offered for this situation ...

  17. Extending cosmology: the metric approach

    OpenAIRE

    Mendoza, S.

    2012-01-01

    Comment: 2012, Extending Cosmology: The Metric Approach, Open Questions in Cosmology; Review article for an Intech "Open questions in cosmology" book chapter (19 pages, 3 figures). Available from: http://www.intechopen.com/books/open-questions-in-cosmology/extending-cosmology-the-metric-approach

  18. Current approaches to norms research

    Science.gov (United States)

    John L. Heywood

    2000-01-01

    The dialogue session was a continuation of a debate about norms and the application of normative standards to wilderness management that has taken place throughout the 1990s at national meetings and in the research literature. Researchers who have made significant contributions to the normative approach to wilderness recreation management presented three approaches to...

  19. Workplace English: Approach and Analysis.

    Science.gov (United States)

    Prince, David

    1984-01-01

    Describes two approaches to teaching vocational English as a second language: (1) describing work activities in terms of processes and procedures and (2) describing work activities in terms of specific human behaviors. Suggests a goal analysis as an initial step before deciding which approach to take in any training project. (SED)

  20. An approach to the future

    Science.gov (United States)

    Peter C. Bishop

    2012-01-01

    This paper describes the rudiments of an approach to the future that we should teach and practice in our personal and professional lives. It begins with a consideration of change. The future is about change. If there were no change, we would have no reason to pay attention to the future. The paper concludes with an approach to long-term forecasting that takes...

  1. Adolescent Suicide: An Ecological Approach.

    Science.gov (United States)

    Ayyash-Abdo, Huda

    2002-01-01

    Proposes an ecological approach to enhance our understanding of how personal, interpersonal, and sociocultural factors contribute to the increased risk for suicide among adolescents. The ecological approach allows exploration of how adolescent suicide is determined by multiple factors related to the adolescent's personal history or ontogenic…

  2. Alcoholism: A Family System Approach

    Science.gov (United States)

    Foley, Vincent D.

    1976-01-01

    One approach to the problem of alcohol is to see it less as that of an individual's and more as the result of the interaction of a given family system. A structural approach is suggested in which the family system is examined and rearranged into a new and functioning system. (Author/NG)

  3. Library Administration: A Humanistic Approach.

    Science.gov (United States)

    Hood, Lillian

    1980-01-01

    Discusses the tasks of library administration in relation to autocratic, participatory, and contingency approaches to management problems. The psychological and organizational side-effects of the three management styles are considered and a humanistic combination of approaches is suggested. A bibliography is included. (JL)

  4. Systems Approach to Environmental Pollution.

    Science.gov (United States)

    Chacko, George K., Ed.

    The objective of a two-day Symposium on Systems Approach to Environmental Pollution of the Operations Research Society of America at the 137th Annual Meeting of the American Association for the Advancement of Science, December 27-28, 1970 in Chicago, Illinois, was not to raise the litany of a systems approach as the answer to all environmental…

  5. THE APPROACHING TRAIN DETECTION ALGORITHM

    Directory of Open Access Journals (Sweden)

    S. V. Bibikov

    2015-09-01

    Full Text Available The paper deals with detection algorithm for rail vibroacoustic waves caused by approaching train on the background of increased noise. The urgency of algorithm development for train detection in view of increased rail noise, when railway lines are close to roads or road intersections is justified. The algorithm is based on the method of weak signals detection in a noisy environment. The information statistics ultimate expression is adjusted. We present the results of algorithm research and testing of the train approach alarm device that implements the proposed algorithm. The algorithm is prepared for upgrading the train approach alarm device “Signalizator-P".

  6. Probabilistic approach to pattern selection

    Science.gov (United States)

    Yukalov, V. I.

    2001-03-01

    The problem of pattern selection arises when the evolution equations have many solutions, whereas observed patterns constitute a much more restricted set. An approach is advanced for treating the problem of pattern selection by defining the probability distribution of patterns. Then the most probable pattern naturally corresponds to the largest probability weight. This approach provides the ordering principle for the multiplicity of solutions explaining why some of them are more preferable than others. The approach is applied to solving the problem of turbulent photon filamentation in resonant media.

  7. A Biosemiotic Approach to Health

    DEFF Research Database (Denmark)

    Hoffmeyer, Jesper

    2010-01-01

    By replacing the traditional chemical approach to the understanding of body function by a sign-theoretic or semiotic approach, biosemiotics enters a no-man’s-land between biological and social domains of human life. The aim is not to subsume the social under the biological or vice versa; both...... approaches are invaluable. The aim is to find a common platform that serves in treating human persons as undivided wholes. Since semiosis (viz. the meaningful interpretation of cues, signals, events or states) is vital to communication at both levels, the resulting sign-process is a viable choice...... as the basis for an integrated theory of health....

  8. Vanpooling: the three major approaches

    Energy Technology Data Exchange (ETDEWEB)

    Sears, P.M.

    1979-08-01

    The manual provides technical assistance to existing or prospective vanpool sponsors. It is designed to help them promote vanpooling in its three major approaches: employer sponsored, third party sponsored, and driver owned and operated. The first chapter is an overview of vanpooling and a second chapter, on vanpool marketing, is addressed to ridesharing coordinators and others whose responsibilities include the promotion of vanpooling. Some fact sheets on the three approaches provide convenient summaries of the needs and opportunities of each approach and suggest solutions to practical problems likely to be encountered in starting new vanpool programs.

  9. Approaches to Scandinavian Crime Fiction

    DEFF Research Database (Denmark)

    Agger, Gunhild

    2010-01-01

    The working paper discusses some of the major approaches to Scandinavian crime fiction in the light of the dominant features of crime culture, e.g. the broad exposure of crime fiction via different platforms and media. In this connection, the concept of mediatization is considered as well...... as the approach of genre typology and the concept of evil – seemingly disparate concepts and approaches, but all related to the complex processes in the borderlands between crime fiction and society. Using examples from Scandinavian crime fiction, I discuss whether the growing proximity to international genres......, ways of production and standards increasingly removes Scandinavian crime fiction from its original attractions or not....

  10. Approaches for assessing sustainable remediation

    DEFF Research Database (Denmark)

    Søndergaard, Gitte Lemming; Binning, Philip John; Bjerg, Poul Løgstrup

    remediation strategies for a contaminated site. Most approaches use multi-criteria assessment methods (MCA) to structure a decision support process. Different combinations of environmental, social and economic criteria are employed, and are assessed either in qualitative or quantitative forms with various...... tools such as life cycle assessment and cost benefit analysis. Stakeholder involvement, which is a key component of sustainable remediation, is conducted in various ways. Some approaches involve stakeholders directly in the evaluation or weighting of criteria, whereas other approaches only indirectly...

  11. Approaches to Teaching Organizational Communication.

    Science.gov (United States)

    Applebaum, Ronald L.

    1998-01-01

    Discusses fundamental problems in selecting an approach to organizational communications; the purpose of an organizational communication course; the structure and content of organizational communication coursework; and teaching strategies used in the basic course in organizational communication. (RS)

  12. Nonlinear Approaches in Engineering Applications

    CERN Document Server

    Jazar, Reza

    2012-01-01

    Nonlinear Approaches in Engineering Applications focuses on nonlinear phenomena that are common in the engineering field. The nonlinear approaches described in this book provide a sound theoretical base and practical tools to design and analyze engineering systems with high efficiency and accuracy and with less energy and downtime. Presented here are nonlinear approaches in areas such as dynamic systems, optimal control and approaches in nonlinear dynamics and acoustics. Coverage encompasses a wide range of applications and fields including mathematical modeling and nonlinear behavior as applied to microresonators, nanotechnologies, nonlinear behavior in soil erosion,nonlinear population dynamics, and optimization in reducing vibration and noise as well as vibration in triple-walled carbon nanotubes. This book also: Provides a complete introduction to nonlinear behavior of systems and the advantages of nonlinearity as a tool for solving engineering problems Includes applications and examples drawn from the el...

  13. Approach to lower back pain

    African Journals Online (AJOL)

    the number of work days lost. LBP, by ... and psychologically taxing work are also risk factors. ... that in a primary care setting the majority of patents have nonspecific .... multidisciplinary team approach, employing pharmacological and non.

  14. Radiological Approach to Forefoot Pain

    Directory of Open Access Journals (Sweden)

    Sai Chung Ho

    2015-06-01

    Full Text Available Forefoot pain is a common clinical complaint in orthopaedic practice. In this article, we discuss the anatomy of the forefoot, clinical and radiological approaches to forefoot pain, and common painful forefoot disorders and their associated radiological features.

  15. Treatment Approaches for Drug Addiction

    Science.gov (United States)

    ... Trends Nationwide Trends Prevention and Treatment Lessons from Prevention Research Substance Abuse in the Military Treatment Approaches for Drug Addiction Get this Publication Español PDF (773KB) Cite this ...

  16. Fibromyalgia and Complementary Health Approaches

    Science.gov (United States)

    ... R S T U V W X Y Z Fibromyalgia: In Depth Share: On This Page What’s the ... about the effectiveness of complementary health approaches for fibromyalgia? Although some studies of tai chi , yoga , mindfulness ...

  17. Humane Education: A Curriculum Approach.

    Science.gov (United States)

    Pearce, Robert W.

    1980-01-01

    Describes a curriculum-based approach to humane education and addresses the role of humane education in the school curriculum as well as the relationship's of education to other facets of animal welfare work. (Author/DS)

  18. Paraspinal approach for thoracolumbar fracture

    Directory of Open Access Journals (Sweden)

    JIANG Rui

    2011-02-01

    Full Text Available 【Abstract】Objective: To explore the advantages and indications of the paraspinal approach by anatomical study and clinical application. Methods: The anatomical data and clinical practice of 27 cases were analyzed to explore the accurate approach between the paraspinal muscles and the structure of ambient tissues, as well as the results of clinical application of paraspinal approach. The operation time, blood loss, incision length, radiographic result (Cobb angle, height of anterior edge of the vertebrae were compared with those in 24 cases treated by traditional approach. Results: Complete exposure of the facets could be easily performed by identifying natural cleavage plane between the multifidus and longissimus muscles. The natural muscular cleavage was (1.47±0.23 cm lateral to the midline for females, and (1.64±0.35 cm for males at T12 level. The distance was (3.3±0.6 cm lateral to the midline for females, and (3.7±1.0 cm for males at L4 level. In paraspinal approach group, the operation time was (76.2±15.7 min, blood loss was (91.6±16.9 ml and incision length was (7.6±0.8 cm. In traditional approach group, the operation time was (121.4±19.6 min, blood loss was (218.7±32.3 ml and incision length was (17.4±2.1 cm. To compare paraspinal approach with traditional approach, the operation time, blood loss and incision length had statistical difference (P<0.05 and the radiographic result (Cobb angle, height of anterior edge of the vertebrae had no statistical difference (P>0.05. Conclusions: When the paraspinal approach is performed through natural cleavage plane between the multifidus and longissimus muscles, there are no wide muscular disinsertions, leaving the supraspinous and interspinous ligaments intact. The distance of natural cleavage to the midline is different at T12 and L4 planes. By this approach, the facet joints can be explored easily and completely, and a clear surgical field will be available for the placement of

  19. An approach to chaotic synchronization

    OpenAIRE

    Hramov, Alexander E.; Koronovskii, Alexey A.

    2005-01-01

    This paper deals with the chaotic oscillator synchronization. A new approach to the synchronization of chaotic oscillators has been proposed. This approach is based on the analysis of different time scales in the time series generated by the coupled chaotic oscillators. It has been shown that complete synchronization, phase synchronization, lag synchronization and generalized synchronization are the particular cases of the synchronized behavior called as "time-scale synchronization". The quan...

  20. Bounding approaches to system identification

    CERN Document Server

    Norton, John; Piet-Lahanier, Hélène; Walter, Éric

    1996-01-01

    In response to the growing interest in bounding error approaches, the editors of this volume offer the first collection of papers to describe advances in techniques and applications of bounding of the parameters, or state variables, of uncertain dynamical systems. Contributors explore the application of the bounding approach as an alternative to the probabilistic analysis of such systems, relating its importance to robust control-system design.

  1. Approaches toward learning in physiotherapy

    Directory of Open Access Journals (Sweden)

    L. Keiller

    2013-01-01

    Full Text Available The aim of this study was to investigate the approaches toward learning of undergraduate Physiotherapy students in a PBl module to enhance facilitation of learning at the Stellenbosch University, Division of Physiotherapy in South Africa. This quantitative, descriptive study utilized the revised Two-factor Study Process Questionnaire (r-SPQ-2f to evaluate the study cohorts’ approaches toward learning in the module. results of the data instruments were analysed statistically and discussed in a descriptive manner. There were a statistically significant greater number of students who adopted a deep approach toward learning at the commencement of the academic year. Students showed a trend toward an increase in their intrinsic interest in the learning material as the module progressed. Students in the Applied Physiotherapy module (ATP started to shift their focus from a surface learning approach to a deep learning approach. further research is needed to determine the long-term changes in approach toward learning and the possible determinants of these changes. This can be done in conjunction with the implementation of quality assurance mechanisms for learning material and earlier preparation of students for the change in the learning environment.

  2. Approach

    Directory of Open Access Journals (Sweden)

    Guido Pinto Aguirre

    2008-01-01

    Full Text Available El propósito de este documento es investigar y re-estimar los efectos de los patrones de lactancia, salud y estado nutricional de la mujer y consumo de energía sobre la duración del retorno de la fertilidad de postparto (es decir, retorno de la menstruación de postparto utilizando toda la información relevante en el estudio longitudinal del Instituto de Nutrición de Centroamérica y Panamá y un procedimiento de estimación más adecuado (modelos de riesgo. Los datos utilizados provienen del Estudio Longitudinal llevado a cabo en Guatemala entre 1967 y 1979. En este artículo se utiliza un modelo de riesgo con varios estados que reconoce diferentes caminos y estados en el proceso del retorno de la fertilidad de postparto. El modelo descansa en la existencia de cinco estados (lactancia total, lactancia parcial, destete, mortalidad infantil y menstruación. También incluye de manera explícita nutrición maternal y consumo de energía de la mujer como elementos estratégicos del modelo. El estudio encontró que los efectos de los patrones de lactancia, nutrición de la madre y patrones de trabajo de la mujer (consumo de energía sobre la fertilidad en las áreas rurales de Guatemala son fuertes y significativos. La contribución de este artículo es mostrar que la aplicación de los modelos de riesgo con múltiples estados proporciona estimados que son consistentes con hipótesis que relacionan patrones de lactancia, estado nutricional maternal y estresores maternales externos a procesos que aceleran (desaceleran el retorno de ciclos menstruales normales.

  3. A systems approach to obesity.

    Science.gov (United States)

    Lee, Bruce Y; Bartsch, Sarah M; Mui, Yeeli; Haidari, Leila A; Spiker, Marie L; Gittelsohn, Joel

    2017-01-01

    Obesity has become a truly global epidemic, affecting all age groups, all populations, and countries of all income levels. To date, existing policies and interventions have not reversed these trends, suggesting that innovative approaches are needed to transform obesity prevention and control. There are a number of indications that the obesity epidemic is a systems problem, as opposed to a simple problem with a linear cause-and-effect relationship. What may be needed to successfully address obesity is an approach that considers the entire system when making any important decision, observation, or change. A systems approach to obesity prevention and control has many benefits, including the potential to further understand indirect effects or to test policies virtually before implementing them in the real world. Discussed here are 5 key efforts to implement a systems approach for obesity prevention: 1) utilize more global approaches; 2) bring new experts from disciplines that do not traditionally work with obesity to share experiences and ideas with obesity experts; 3) utilize systems methods, such as systems mapping and modeling; 4) modify and combine traditional approaches to achieve a stronger systems orientation; and 5) bridge existing gaps between research, education, policy, and action. This article also provides an example of how a systems approach has been used to convene a multidisciplinary team and conduct systems mapping and modeling as part of an obesity prevention program in Baltimore, Maryland. © The Author(s) 2016. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  4. Laparoscopic approach in gastrointestinal emergencies.

    Science.gov (United States)

    Jimenez Rodriguez, Rosa M; Segura-Sampedro, Juan José; Flores-Cortés, Mercedes; López-Bernal, Francisco; Martín, Cristobalina; Diaz, Verónica Pino; Ciuro, Felipe Pareja; Ruiz, Javier Padillo

    2016-03-07

    This review focuses on the laparoscopic approach to gastrointestinal emergencies and its more recent indications. Laparoscopic surgery has a specific place in elective procedures, but that does not apply in emergency situations. In specific emergencies, there is a huge range of indications and different techniques to apply, and not all of them are equally settle. We consider that the most controversial points in minimally invasive procedures are indications in emergency situations due to technical difficulties. Some pathologies, such as oesophageal emergencies, obstruction due to colon cancer, abdominal hernias or incarcerated postsurgical hernias, are nearly always resolved by conventional surgery, that is, an open approach due to limited intraabdominal cavity space or due to the vulnerability of the bowel. These technical problems have been solved in many diseases, such as for perforated peptic ulcer or acute appendectomy for which a laparoscopic approach has become a well-known and globally supported procedure. On the other hand, endoscopic procedures have acquired further indications, relegating surgical solutions to a second place; this happens in cholangitis or pancreatic abscess drainage. This endoluminal approach avoids the need for laparoscopic development in these diseases. Nevertheless, new instruments and new technologies could extend the laparoscopic approach to a broader array of potentials procedures. There remains, however, a long way to go.

  5. an alternative approach to t reservations for hand ative approach

    African Journals Online (AJOL)

    eobe

    ETF CENTRE OF EXCELLENCE IN COMM. N. E-m. ABSTRACT. This work presents an alternative approach to the c network for handover call requests. Prioritizing so as to guarantee seamless connection. Successful h the later is directly dependent on call continuit reservations to be made was determined using the G.

  6. Approaches to Teaching Early Reading: Whole Language or Phonic Approach?

    Directory of Open Access Journals (Sweden)

    Didi Sukyadi

    1998-01-01

    Full Text Available Abstract: The impacts of the great debate on early reading instruc­tion, which was started in the late 1960 and early 1970s, remain until today. In our education system, curriculum change also brings about the change of teaching ideology. For teachers, the result sometimes is more threatening than encouraging because they cannot anticipate the quick and inevitable change. They become disempowered and deprived, and that innovation is often difficult to implement. This study aimed to explore the orientation of student teachers and expe­rienced teachers towards reading instruction, namely phonic, skills, and whole language approach. This involved 30 primary student teachers of an Institute of Education in London and 30 experienced teachers teaching at Year 1 and 2 London inner city primary schools. Each of the respondents was sent a questionnaire, and asked to answer an open ended question concerning the best approach of teaching reading. The results revealed that in general there was no difference in teaching reading orientation between student teachers and experienced teachers. Both of them tend to believe that there was no single best method. The competing approaches are seen as comple­mentary. Any approach chosen should take into account child devel­opment, the nature of reading and environmental support. The impli­cations of these findings for teacher empowerment are discussed.

  7. New approaches to antibiotic discovery.

    Science.gov (United States)

    Kealey, C; Creaven, C A; Murphy, C D; Brady, C B

    2017-06-01

    New antibiotics are urgently required by human medicine as pathogens emerge with developed resistance to almost all antibiotic classes. Pioneering approaches, methodologies and technologies have facilitated a new era in antimicrobial discovery. Innovative culturing techniques such as iChip and co-culturing methods which use 'helper' strains to produce bioactive molecules have had notable success. Exploiting antibiotic resistance to identify antibacterial producers performed in tandem with diagnostic PCR based identification approaches has identified novel candidates. Employing powerful metagenomic mining and metabolomic tools has identified the antibiotic'ome, highlighting new antibiotics from underexplored environments and silent gene clusters enabling researchers to mine for scaffolds with both a novel mechanism of action and also few clinically established resistance determinants. Modern biotechnological approaches are delivering but will require support from government initiatives together with changes in regulation to pave the way for valuable, efficacious, highly targeted, pathogen specific antimicrobial therapies.

  8. Solid mechanics a variational approach

    CERN Document Server

    Dym, Clive L

    2013-01-01

    Solid Mechanics: A Variational Approach, Augmented Edition presents a lucid and thoroughly developed approach to solid mechanics for students engaged in the study of elastic structures not seen in other texts currently on the market. This work offers a clear and carefully prepared exposition of variational techniques as they are applied to solid mechanics. Unlike other books in this field, Dym and Shames treat all the necessary theory needed for the study of solid mechanics and include extensive applications. Of particular note is the variational approach used in developing consistent structural theories and in obtaining exact and approximate solutions for many problems.  Based on both semester and year-long courses taught to undergraduate seniors and graduate students, this text is geared for programs in aeronautical, civil, and mechanical engineering, and in engineering science. The authors’ objective is two-fold: first, to introduce the student to the theory of structures (one- and two-dimensional) as ...

  9. Toward predicate approaches to modality

    CERN Document Server

    Stern, Johannes

    2016-01-01

    In this volume, the author investigates and argues for, a particular answer to the question: What is the right way to logically analyze modalities from natural language within formal languages? The answer is: by formalizing modal expressions in terms of predicates. But, as in the case of truth, the most intuitive modal principles lead to paradox once the modal notions are conceived as predicates. The book discusses the philosophical interpretation of these modal paradoxes and argues that any satisfactory approach to modality will have to face the paradoxes independently of the grammatical category of the modal notion. By systematizing modal principles with respect to their joint consistency and inconsistency, Stern provides an overview of the options and limitations of the predicate approach to modality that may serve as a useful starting point for future work on predicate approaches to modality. Stern also develops a general strategy for constructing philosophically attractive theories of modal notions conce...

  10. City evacuations an interdisciplinary approach

    CERN Document Server

    Binner, Jane; Branicki, Layla; Galla, Tobias; Jones, Nick; King, James; Kolokitha, Magdalini; Smyrnakis, Michalis

    2015-01-01

    Evacuating a city is a complex problem that involves issues of governance, preparedness education, warning, information sharing, population dynamics, resilience and recovery. As natural and anthropogenic threats to cities grow, it is an increasingly pressing problem for policy makers and practitioners.   The book is the result of a unique interdisciplinary collaboration between researchers in the physical and social sciences to consider how an interdisciplinary approach can help plan for large scale evacuations.  It draws on perspectives from physics, mathematics, organisation theory, economics, sociology and education.  Importantly it goes beyond disciplinary boundaries and considers how interdisciplinary methods are necessary to approach a complex problem involving human actors and increasingly complex communications and transportation infrastructures.   Using real world case studies and modelling the book considers new approaches to evacuation dynamics.  It addresses questions of complexity, not only ...

  11. Market-based approaches to tree valuation

    Science.gov (United States)

    Geoffrey H. Donovan; David T. Butry

    2008-01-01

    A recent four-part series in Arborist News outlined different appraisal processes used to value urban trees. The final article in the series described the three generally accepted approaches to tree valuation: the sales comparison approach, the cost approach, and the income capitalization approach. The author, D. Logan Nelson, noted that the sales comparison approach...

  12. Elementary calculus an infinitesimal approach

    CERN Document Server

    Keisler, H Jerome

    2012-01-01

    This first-year calculus book is centered around the use of infinitesimals, an approach largely neglected until recently for reasons of mathematical rigor. It exposes students to the intuition that originally led to the calculus, simplifying their grasp of the central concepts of derivatives and integrals. The author also teaches the traditional approach, giving students the benefits of both methods.Chapters 1 through 4 employ infinitesimals to quickly develop the basic concepts of derivatives, continuity, and integrals. Chapter 5 introduces the traditional limit concept, using approximation p

  13. Real analysis a constructive approach

    CERN Document Server

    Bridger, Mark

    2012-01-01

    A unique approach to analysis that lets you apply mathematics across a range of subjects This innovative text sets forth a thoroughly rigorous modern account of the theoretical underpinnings of calculus: continuity, differentiability, and convergence. Using a constructive approach, every proof of every result is direct and ultimately computationally verifiable. In particular, existence is never established by showing that the assumption of non-existence leads to a contradiction. The ultimate consequence of this method is that it makes sense-not just to math majors but also to students from a

  14. A Psycho-Societal Approach

    DEFF Research Database (Denmark)

    Mellon, Karsten

    This is a project about Danish vocational bachelor students admitted on the basis of an Individual Competency Assessment (VPL/IKV) in light of a Psycho-Societal Approach. The core idea of this paper is to present a PhD project which aims to contribute findings regarding students enrolled in a Dan......This is a project about Danish vocational bachelor students admitted on the basis of an Individual Competency Assessment (VPL/IKV) in light of a Psycho-Societal Approach. The core idea of this paper is to present a PhD project which aims to contribute findings regarding students enrolled...

  15. A practical approach to TQI.

    Science.gov (United States)

    Perras, S T; Mattern, M

    1994-04-01

    Total quality improvement (TQI) is a refreshing new approach to leadership that can be applied to a dialysis setting. The team approach to prospective data analysis is used for problem solution and reevaluation. Adapting theory to daily practical application can be successfully done using time, energy, and full senior management commitment. Staff education and involvement are essential to successful program implementation. Evaluation tools are easily adapted to analyze common dialysis problems. The initial time invested in education and data collection can be great but results in a streamlined process.

  16. New Approaches to Reliability Assessment

    DEFF Research Database (Denmark)

    Ma, Ke; Wang, Huai; Blaabjerg, Frede

    2016-01-01

    of energy. New approaches for reliability assessment are being taken in the design phase of power electronics systems based on the physics-of-failure in components. In this approach, many new methods, such as multidisciplinary simulation tools, strength testing of components, translation of mission profiles......, and statistical analysis, are involved to enable better prediction and design of reliability for products. This article gives an overview of the new design flow in the reliability engineering of power electronics from the system-level point of view and discusses some of the emerging needs for the technology...

  17. Systems biology approach to bioremediation

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, Romy; Wu, Cindy H.; Hazen, Terry C.

    2012-06-01

    Bioremediation has historically been approached as a ‘black box’ in terms of our fundamental understanding. Thus it succeeds and fails, seldom without a complete understanding of why. Systems biology is an integrated research approach to study complex biological systems, by investigating interactions and networks at the molecular, cellular, community, and ecosystem level. The knowledge of these interactions within individual components is fundamental to understanding the dynamics of the ecosystem under investigation. Finally, understanding and modeling functional microbial community structure and stress responses in environments at all levels have tremendous implications for our fundamental understanding of hydrobiogeochemical processes and the potential for making bioremediation breakthroughs and illuminating the ‘black box’.

  18. Approaching Bose-Einstein Condensation

    Science.gov (United States)

    Ferrari, Loris

    2011-01-01

    Bose-Einstein condensation (BEC) is discussed at the level of an advanced course of statistical thermodynamics, clarifying some formal and physical aspects that are usually not covered by the standard pedagogical literature. The non-conventional approach adopted starts by showing that the continuum limit, in certain cases, cancels out the crucial…

  19. DEMOCRATIC APPROACHES TO ENVIRONMENTAL EDUCATION ...

    African Journals Online (AJOL)

    approach. Various explanations are offered for this situation although all agree that the principles, goals and processes of democratic pedagogy are often antithetical to the processes of contemporary schooling. Based on a case study of an attempt at democratic pedagogy in an Australian primary school, this paper explores.

  20. Indecisiveness: A Dynamic, Integrative Approach.

    Science.gov (United States)

    Johnson, Douglas Paul

    1990-01-01

    Responds to case of Sondra presented in Career Development Quarterly (September 1990). Suggests that her inability to decide on a career may be rooted in long-term personality style, poor ego strength, noisome family dynamics, and/or developmental delay. Recommends an integrative approach incorporating both personal and career counseling. (PVV)

  1. INTEGRATED EXPERIENCE APPROACH TO LEARNING.

    Science.gov (United States)

    POSTLETHWAIT, S.N.; AND OTHERS

    THE USE OF AUDIOTUTORIAL TECHNIQUES FOR TEACHING INTRODUCTORY COLLEGE BOTANY IS DESCRIBED. SPECIFIC PRACTICES USED AT PURDUE UNIVERSITY TO ILLUSTRATE DIFFERENT FACETS OF THE APPROACH ARE ANALYZED. INCLUDED ARE INDEPENDENT STUDY SESSIONS, SMALL ASSEMBLY SESSIONS, GENERAL ASSEMBLY SESSIONS, AND HOME STUDY SESSIONS. ILLUSTRATIONS AND SPECIFICATIONS…

  2. On psychoanalytic approaches to autism.

    Science.gov (United States)

    Hobson, R P

    1990-07-01

    An analysis of the strengths and limitations of psychoanalytic approaches to autism serves to highlight the need for a theoretical scheme adequate to encompass social as well as cognitive development in autistic individuals. It is proposed that such a scheme will entail an account of normal development in which children's "object relations" feature prominently.

  3. Ethnic Studies: Issues and Approaches.

    Science.gov (United States)

    Yang, Philip Q.

    This book offers a comprehensive definition of the field of ethnic studies, covering both major issues in the field and its theoretical and methodological approaches. It traces the origins and evolution of the discipline in the United States and maps its domain. Some of the current issues addressed include affirmative action, illegal/legal…

  4. Using Natural Approach Teaching Techniques.

    Science.gov (United States)

    Whitman, Charles

    1986-01-01

    Describes a beginning foreign language class applying the principles of Stephen Krashen's "Natural Approach" and James Asher's "Total Physical Response" method. Initially students carry out the instructor's commands in the form of actions rather than being required to speak. In later stages role play and simple discussions are…

  5. Eschenmoser Approach to Vitamin B

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 19; Issue 7. Eschenmoser Approach to Vitamin B12 by A/D Strategy: An Unexpected Journey. G Wayne Craig. General Article Volume 19 Issue 7 July 2014 pp 624-640. Fulltext. Click here to view fulltext PDF. Permanent link:

  6. An analogical approach to grammaticalization

    NARCIS (Netherlands)

    Fischer, O.; Stathi, K.; Gehweiler, E.; König, E.

    2010-01-01

    Two well-known approaches to language change illustrate a fundamental difference between functional and formal linguistics as to what are considered important mechanisms in change. In Grammaticalization, emphasis is on the semantic-pragmatic factors guiding change, while Generative Theory

  7. Petrov classification: An elementary approach

    Energy Technology Data Exchange (ETDEWEB)

    Kalotas, T.M.; Eliezer, C.J.

    1983-01-01

    We reduce the length of the usual algebraic classification scheme of the Weyl tensor by avoiding the step centered around its reduction to canonical form. Instead the different algebraic types are established more economically via the elementary approach of constructing explicit examples.

  8. Therapeutic approaches to genetic disorders

    African Journals Online (AJOL)

    salah

    hemophilia and many storage disor- ders), cell-tissue-organ transplantation. (e.g for many disorders like tyrosinemia and polycystic kidney disease), surgical intervention for genetically-determined congenital malformations and late de- veloping surgically correctable com- plications and gene therapy approaches.

  9. Appreciating Music: An Active Approach

    Science.gov (United States)

    Levin, Andrew R.; Pargas, Roy P.

    2005-01-01

    A particularly innovative use of laptops is to enhance the music appreciation experience. Group listening and discussion, in combination with a new Web-based application, lead to deeper understanding of classical music. ["Appreciating Music: An Active Approach" was written with Joshua Austin.

  10. Japanese approaches to development communication

    OpenAIRE

    Wilkins, Karin Gwinn

    2003-01-01

    Development communication literature neglects attention to Japanese approaches to development practice as a prominent donor institution. Based on a series of interviews and document reviews, this analysis characterizes how Japanese development projects use communication technologies to address a variety of development goals. Moreover, this research explores how this development discourse constructs social problems, beneficiaries, and appropriate solutions. Japan's development communication ap...

  11. Interdisciplinary approaches in career studies

    NARCIS (Netherlands)

    Khapova, S.N.; Arthur, M.B.

    2011-01-01

    This is the opening article in a Human Relations special issue on 'Interdisciplinary approaches to contemporary career studies'. After introducing a story of an 'exceptional - but real' career, we argue for an urgent shift toward greater interdisciplinary inquiry. We reflect on the story to describe

  12. Novel approaches to epilepsy treatment

    DEFF Research Database (Denmark)

    Sørensen, Andreas T; Kokaia, Merab

    2013-01-01

    The aim of epilepsy treatment is to achieve complete seizure freedom. Nonetheless, numerous side effects and seizure resistance to antiepileptic drugs (AEDs) affecting about 30-40% of all patients are main unmet needs in today's epileptology. For this reason, novel approaches to treat epilepsy ar...

  13. International Approaches to Clinical Costing

    DEFF Research Database (Denmark)

    Chapman, Christopher; Kern, Anja; Laguecir, Aziza

    This report has been commissioned by both HFMA and Monitor and the work has been led by Imperial College Business School’s Health Management Group. The report compares current approaches to costing, primarily across Europe. The findings reveal wide-ranging practices and uses for costing data...

  14. Theoretical Approaches to Political Communication.

    Science.gov (United States)

    Chesebro, James W.

    Political communication appears to be emerging as a theoretical and methodological academic area of research within both speech-communication and political science. Five complimentary approaches to political science (Machiavellian, iconic, ritualistic, confirmational, and dramatistic) may be viewed as a series of variations which emphasize the…

  15. Integrative approaches: promoting socioecological resilience

    Science.gov (United States)

    J.W. Long; Carl Skinner; M. North; C.T. Hunsaker; L. Quinn-Davidson

    2014-01-01

    This chapter begins by discussing current challenges for ecosystem management that emerged from multiple chapters of the full synthesis. It then considers integrative approaches to promote resilience, including general strategies that recognize the integrated nature of socioecological systems, the importance of promoting disturbance regimes upon which these systems...

  16. Corpus Approaches to Language Ideology

    Science.gov (United States)

    Vessey, Rachelle

    2017-01-01

    This paper outlines how corpus linguistics--and more specifically the corpus-assisted discourse studies approach--can add useful dimensions to studies of language ideology. First, it is argued that the identification of words of high, low, and statistically significant frequency can help in the identification and exploration of language ideologies…

  17. Integrated reclamation: Approaching ecological function?

    Science.gov (United States)

    Ann L. Hild; Nancy L. Shaw; Ginger B. Paige; Mary I. Williams

    2009-01-01

    Attempts to reclaim arid and semiarid lands have traditionally targeted plant species composition. Much research attention has been directed to seeding rates, species mixes and timing of seeding. However, in order to attain functioning systems, attention to structure and process must compliment existing efforts. We ask how to use a systems approach to enhance...

  18. a systemic functional linguistic approach

    African Journals Online (AJOL)

    Analysing social identity in casual Zambian/English conversation: a systemic functional linguistic approach. ... Through an analysis of sentence-level grammatical patterns, and of speakers' mood choices in particular, the study shows how interactants construct identities ('self' and 'other') and social roles, as well as role ...

  19. Eight Approaches to Language Teaching.

    Science.gov (United States)

    Doggett, Gina

    Important features of eight second language teaching methods--grammar-translation, direct, audiolingual, the Silent Way, Suggestopedia, community language learning, Total Physical Response, and the communicative approach--are summarized . A chart outlines characteristics of these aspects of the methods: goals, teacher and student roles, the…

  20. Mathematical Analysis, A Straightforward Approach

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 4; Issue 4. Mathematical Analysis, A Straightforward Approach. K Rama Murthy. Book Review Volume 4 Issue 4 April 1999 pp 96-96. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/004/04/0096-0096 ...

  1. THEORETICAL APPROACHES IN INTERNATIONAL RELATIONS ...

    African Journals Online (AJOL)

    plt

    constitutes a distinctive 'lens' on world affairs.9 The question can be raised as to how, and if, theoretical approaches in IR can contribute to an improved understanding of the role and functions of militaries. There are concrete or specific theories, such as Realism, but not even realist theories guarantee a clear and accurate.

  2. Geometrical approach to fluid models

    NARCIS (Netherlands)

    Kuvshinov, B. N.; Schep, T. J.

    1997-01-01

    Differential geometry based upon the Cartan calculus of differential forms is applied to investigate invariant properties of equations that describe the motion of continuous media. The main feature of this approach is that physical quantities are treated as geometrical objects. The geometrical

  3. Institutional Planning: A Systems Approach.

    Science.gov (United States)

    Adamson, Willie D.

    This four-chapter report explores the possible contributions of a systems approach to institutional planning. After introductory comments, Chapter I reviews the management theory of Henry Fayol, which emphasizes management tasks, such as planning, organizing, commanding, coordinating, and controlling, which are "universal" regardless of the level…

  4. Therapeutic approaches to genetic disorders

    African Journals Online (AJOL)

    salah

    Although prevention is the ideal goal for genetic disorders, various types of therapeutic management are available. Such management approaches depend on the nature of the defect, how well it is understood at the genetic and bio- chemical levels and the practical feasibility of correction. In some conditions.

  5. Novel Approaches to Surfactant Administration

    OpenAIRE

    Gupta, Samir; Donn, Steven M.

    2012-01-01

    Surfactant replacement therapy has been the mainstay of treatment for preterm infants with respiratory distress syndrome for more than twenty years. For the most part, surfactant is administered intratracheally, followed by mechanical ventilation. In recent years, the growing interest in noninvasive ventilation has led to novel approaches of administration. This paper will review these techniques and the associated clinical evidence.

  6. Planning approaches for rurban areas

    DEFF Research Database (Denmark)

    Busck, Anne Gravsholt; Hidding, Marjan; Kristensen, Søren Bech Pilgaard

    2009-01-01

    encroachment, and how resilient green landscapes are ensured. The results reveal significant differences in approaches, reflecting variations in the public involvement in rurban areas development, the role of different administrative levels and the use of zonation. Variation in the use of zonation encapsulates...

  7. Oncoplastic Approaches to Breast Conservation

    Directory of Open Access Journals (Sweden)

    Dennis R. Holmes

    2011-01-01

    Full Text Available When a woman is diagnosed with breast cancer many aspects of her physical, emotional, and sexual wholeness are threatened. The quickly expanding field of oncoplastic breast surgery aims to enhance the physician commitment to restore the patient's image and self-assurance. By combining a multidisciplinary approach to diagnosis and treatment with oncoplastic surgery, successful results in the eyes of the patient and physician are significantly more likely to occur. As a way to aid oncoplastic teams in determining which approach is most suitable for their patient's tumor size, tumor location, body habitus, and desired cosmetic outcome we present a review of several oncoplastic surgical approaches. For resections located anywhere in the breast, the radial ellipse segmentectomy incision and circumareolar approach for segmental resection are discussed. For resections in the upper or central breast, crescent mastopexy, the batwing incision, the hemibatwing incision, donut mastopexy, B-flap resection, and the central quadrantectomy are reviewed. For lesions of the lower breast, the triangle incision, inframammary incision, and reduction mastopexy are discussed. Surgeons who are interested in adding oncoplastic breast conserving therapies to their skill sets are encouraged to implement these surgical techniques where applicable and to seek out breast fellowships or enhanced training when appropriate.

  8. Multidisciplinary Approaches in Evolutionary Linguistics

    Science.gov (United States)

    Gong, Tao; Shuai, Lan; Wu, Yicheng

    2013-01-01

    Studying language evolution has become resurgent in modern scientific research. In this revival field, approaches from a number of disciplines other than linguistics, including (paleo)anthropology and archaeology, animal behaviors, genetics, neuroscience, computer simulation, and psychological experimentation, have been adopted, and a wide scope…

  9. A Psychoanalytic Approach to Fieldwork

    Science.gov (United States)

    Ramvi, Ellen

    2012-01-01

    This article focuses on what both psychoanalysis and anthropology have in common: the emphasis on the researcher's own experience. An ethnographic fieldwork will be used to illustrate how a psychoanalytical approach unfolds the material when studying conditions for learning from experience among teachers in two Norwegian junior high schools, and…

  10. Minimalist approach to perceptual interactions.

    Science.gov (United States)

    Lenay, Charles; Stewart, John

    2012-01-01

    WORK AIMED AT STUDYING SOCIAL COGNITION IN AN INTERACTIONIST PERSPECTIVE OFTEN ENCOUNTERS SUBSTANTIAL THEORETICAL AND METHODOLOGICAL DIFFICULTIES: identifying the significant behavioral variables; recording them without disturbing the interaction; and distinguishing between: (a) the necessary and sufficient contributions of each individual partner for a collective dynamics to emerge; (b) features which derive from this collective dynamics and escape from the control of the individual partners; and (c) the phenomena arising from this collective dynamics which are subsequently appropriated and used by the partners. We propose a minimalist experimental paradigm as a basis for this conceptual discussion: by reducing the sensory inputs to a strict minimum, we force a spatial and temporal deployment of the perceptual activities, which makes it possible to obtain a complete recording and control of the dynamics of interaction. After presenting the principles of this minimalist approach to perception, we describe a series of experiments on two major questions in social cognition: recognizing the presence of another intentional subject; and phenomena of imitation. In both cases, we propose explanatory schema which render an interactionist approach to social cognition clear and explicit. Starting from our earlier work on perceptual crossing we present a new experiment on the mechanisms of reciprocal recognition of the perceptual intentionality of the other subject: the emergent collective dynamics of the perceptual crossing can be appropriated by each subject. We then present an experimental study of opaque imitation (when the subjects cannot see what they themselves are doing). This study makes it possible to characterize what a properly interactionist approach to imitation might be. In conclusion, we draw on these results, to show how an interactionist approach can contribute to a fully social approach to social cognition.

  11. Technology approaches to currency security

    Science.gov (United States)

    Murphy, John C.; Dubbel, Daniel C.; Benson, Richard C.

    1998-04-01

    The continued development of reprographic technology and computer graphics (notably color laser copiers, scanners and color laser printers) has increased the tools available to both professional and casual counterfeiters. The result is an increase in the counterfeit risk to the U.S. dollar and other currencies. To counter these threats improved methods of currency authentication are needed both for use by the general public and by national currency authorities. The growing number of cash transfer machines has increased the importance of machine readable security features. This paper describes some technology based approaches to currency security based on special materials. It also proposes a metaphor for currency authentication which attempts to provide a framework for unifying approaches based on secure features and those based on codes.

  12. Novel approaches in herbal cosmetics.

    Science.gov (United States)

    Chanchal, Deep; Swarnlata, Saraf

    2008-06-01

    Nutracosmetics are an emerging class of health and beauty aid products that combine the benefits of nutracosmetical ingredients with the elegance, skin feel, and delivery systems of cosmetics. Herbs and spices have been used in maintaining and enhancing human beauty because herbs have many beneficial properties, such as sunscreen, antiaging, moisturizing, antioxidant, anticellulite, and antimicrobial effects. As compared with synthetic cosmetic products, herbal products are mild, biodegradable, and have low toxicity profile. To enhance these properties, research is being done in the development of newer approaches, which could improve both the aesthetic appeal and performance of a cosmetic product. In this respect, the approaches studied and discussed include liposomes, phytosomes, transferosomes, nanoemulsions, nanoparticles, microemulsions, nanocrystals, and cubosomes.

  13. Nanorobotics current approaches and techniques

    CERN Document Server

    Ferreira, Antoine

    2013-01-01

    Nanorobot devices now perform a wide variety of tasks at the nanoscale in a wide variety of fields including but not limited to fields such as manufacturing, medicine, supply chain, biology, and outer space. Nanorobotics: Current Approaches and Techniques is a comprehensive overview of this interdisciplinary field with a wide ranging discussion that includes nano-manipulation and industrial nanorobotics, nanorobotics in biology and medicine, nanorobotic sensing, navigation and swarm behavior, and protein and DNA-based nanorobotics. Also included is the latest on topics such as bio-nano-actuators and propulsion and navigation of nanorobotic systems using magnetic fields. Nanorobotics: Current Approaches and Techniques is an ideal book for scientists, researchers, and engineers actively involved in applied and robotic research and development.

  14. Variational approach in transport theory

    Energy Technology Data Exchange (ETDEWEB)

    Panta Pazos, R. [Nucler Engineering Department, UFRGS, Porto-Alegre (Brazil); Tullio de Vilhena, M. [Institute of Mathematics, UFRGS, Porto-Alegre (Brazil)

    2004-07-01

    In this work we present a variational approach to some methods to solve transport problems of neutral particles. We consider a convex domain X (for example the geometry of a slab, or a convex set in the plane, or a convex bounded set in the space) and we use discrete ordinates quadrature to get a system of differential equations derived from the neutron transport equation. The boundary conditions are vacuum for a subset of the boundary, and of specular reflection for the complementary subset of the boundary. Recently some different approximation methods have been presented to solve these transport problems. We introduce in this work the adjoint equations and the conjugate functions obtained by means of the variational approach. First we consider the general formulation, and then some numerical methods such as spherical harmonics and spectral collocation method. (authors)

  15. 'Academic literacies approaches to genre'?

    Directory of Open Access Journals (Sweden)

    Brian Street

    Full Text Available I provide an overview of approaches to writing referred to as 'academic literacies' building on broader traditions, such as New Literacy Studies, and I draw out the relevance of such traditions for the ways in which lecturers provide support to their students with regard to the writing requirements of the University. I offer three case studies of the application of academic literacies approaches to programmes concerned with supporting student writing, in the UK and the USA. I briefly conclude by asking how far these accounts and this work can be seen to bring together many of the themes raised at SIGET conferences - including academic literacies and its relation to genre theories - and express the hope that it opens up trajectories for future research and collaboration of the kind they were founded to develop.

  16. NEW APPROACHES TO EXPORT COMPETITIVENESS

    Directory of Open Access Journals (Sweden)

    Alina Petronela NEGREA

    2015-04-01

    Full Text Available The economic literature and the political discourse typically look at international competitiveness mainly by the means of export market shares. However, globalisation, production fragmentation and the growing importance of global value chains (GVCs increasingly challenge traditional approaches of export competitiveness and call for a more accurate and disaggregated level of analysis. Due to the growing fragmentation of production, a country exports now include a significant amount of imports of intermediate goods which are part of the export value. In this case, a simple analysis of the evolution of exports can distort the international competitive position of a country. The article suggests a new approach based on the value-added content of international trade measured by means of global value chain analysis.

  17. Malaysia implements the integrated approach.

    Science.gov (United States)

    1977-01-01

    Malaysia has implemented an integrated approach in providing family planning services to eligible couples. In 1964 the government of Malaysia adopted a national family planning program, and implementation began in the urban areas and extended into the rural areas. Other agencies are involved in providing family planning services and information including the Federation of Family Planning Associations, the Ministry of Health, the National Family Planning Board, and the Federal Land Development Authority. The number of women practicing contraception has increased from 20,726 in 1967 to 533,646 by 1976. and other methods, 3.9%, respectively. There has been an increase in the percentage of acceptors between ages 15-29 from 56% in 1968 to 71.3% in 1975. The 2nd Malaysian national plan will use a multidisciplinary approach to the problem.

  18. Approaching work and learning indirectly

    OpenAIRE

    Macintyre, Ronald; Thomson, Joan

    2013-01-01

    This paper approaches work and learning indirectly. It is part of a mixed method longitudinal study that looks at the articulation from Higher National (HN) to part time Higher Education (HE). Since 2003 the Open University in Scotland (OU) has been collecting quantitative and qualitative data on students who have HN qualifications. This paper looks at the experiences of those students and the central place of work in those journeys. \\ud \\ud The paper beings with a statistical overview. HN St...

  19. Intensional Approaches for Symbolic Methods

    OpenAIRE

    Kushnarenko, Olga; Pinchinat, Sophie

    1998-01-01

    We present a behavioral model for discrete event systems based on an intentional formalism, as a possible approach within the broader trend towards rich symbolic representations in verification. We define Intensional Labeled Transition Systems with associated combinators of parallel composition and event hiding, and we propose symbolic bisimulation to handle strong bisimulation intentionally. Further on, we explain how the methodology has been developed for the synchronous language Signal, vi...

  20. MODERN APPROACH TOWARDS IMMUNOMODULATION THERAPY

    Directory of Open Access Journals (Sweden)

    L. S. Namazova-Baranova

    2012-01-01

    Full Text Available This article covers one of the most discussed issues of clinical immunology — the role of dendritic cells in acquired immunity. Modern conception of dendritic cells participating in antigen handling procedure and its presentation, interaction with other immune cells made it possible to change approach towards immunomodulating therapy dramatically and to develop a new class of immunostimulants, that influence simultaneously cell and humoral immunity both in loci of antigen intervention on the mucosal level and systemically.

  1. Architecture Approach in System Development

    Directory of Open Access Journals (Sweden)

    Ladislav Burita

    2017-01-01

    Full Text Available The purpose of this paper is to describe a practical solution of architecture approach in system development. The software application is the system which optimizes the transport service. The first part of the paper defines the enterprise architecture, its parts and frameworks. Next is explained the NATO Architecture Framework (NAF, a tool for command and control systems development in military environment. The NAF is used for architecture design of the system for optimization of the transport service.

  2. Teaching urbanism: the Delft approach

    OpenAIRE

    Nijhuis, S.; Stolk, E.H.; Hoekstra, M.J.

    2016-01-01

    The Department of Urbanism at the Faculty of Architecture and Built Environment at the Delft University of Technology has a long tradition in educating generations of internationally oriented designers, planners and researchers in urbanism. Here the domain of urbanism is defined as an interdisciplinary approach that engages in real-world sociocultural, ecological and technological issues affecting urban landscapes, from the perspective of spatial planning and design. Specifically, it combines...

  3. An automatic image recognition approach

    Directory of Open Access Journals (Sweden)

    Tudor Barbu

    2007-07-01

    Full Text Available Our paper focuses on the graphical analysis domain. We propose an automatic image recognition technique. This approach consists of two main pattern recognition steps. First, it performs an image feature extraction operation on an input image set, using statistical dispersion features. Then, an unsupervised classification process is performed on the previously obtained graphical feature vectors. An automatic region-growing based clustering procedure is proposed and utilized in the classification stage.

  4. Algebraic Approach to Algorithmic Logic

    OpenAIRE

    Bancerek Grzegorz

    2014-01-01

    We introduce algorithmic logic - an algebraic approach according to [25]. It is done in three stages: propositional calculus, quantifier calculus with equality, and finally proper algorithmic logic. For each stage appropriate signature and theory are defined. Propositional calculus and quantifier calculus with equality are explored according to [24]. A language is introduced with language signature including free variables, substitution, and equality. Algorithmic logic requires a bialgebra st...

  5. An approach to risk assessment

    DEFF Research Database (Denmark)

    Simonsen, L.; Lund, S. P.; Hass, Ulla

    1998-01-01

    A strategy for delineating risk factors from use of neurotoxic chemicals was applied to the Danish working environment. An analysis using this strategy disclosed the need for internationally adopted criteria for neurotoxicity, and consequently a working group was established by the Nordic Council...... in the nineties. Different approaches to risk assessment are discussed, the quality of the databases available for hazard assessment are evaluated, and the needs for further research are identified. (C) 1996 Intox Press, Inc....

  6. Postprandial hyperglycemia. II. Pharmacological approaches

    OpenAIRE

    Scheen, André; Letiexhe, Michel; Geronooz, I.; Paquot, Nicolas; Jandrain, Bernard

    2002-01-01

    Besides dietary approaches, various pharmacological means have been recently developed in order to better control postprandial hyperglycaemia. This objective may be obtained: 1) by slowing down the intestinal absorption of carbohydrates; 2) by insuring a better insulin priming soon after the meal; and 3) by inhibiting post-prandial glucagon secretion or action. Some hormones (amylin, glucagon-like peptide-1) can slow gastric emptying while alpha-glucosidase inhibitors (acarbose, miglitol) ret...

  7. The Entrepreneurial Approach in Marketing

    OpenAIRE

    Florin Foltean

    2007-01-01

    The marketing - entrepreneurship interface at corporate level has generated many debates and studies in the last two decades, both in marketing and entrepreneurship fields. Certain elements of marketing orientation and approach may be used in the development of entrepreneurial processes, while entrepreneurial orientation and behavior enhance the marketing performance of a company which operates in a dynamic environment. This paper presents the concept of entrepreneurial marketing, a proposed ...

  8. Complications of the laparoscopic approach.

    Science.gov (United States)

    Hill, D J

    1994-12-01

    Most laparoscopic complications occur as a result of creating and maintaining a pneumoperitoneum and the blind insertion of the first trocar. Thus, it is the complications of the laparoscopic approach rather than the complications of the laparoscopic technique for a specific condition which should be considered. The hazards and the incidences, causes, prevention and management of these complications are discussed using the experience of the author and reported data.

  9. Review og pattern matching approaches

    DEFF Research Database (Denmark)

    Manfaat, D.; Duffy, Alex; Lee, B. S.

    1996-01-01

    This paper presents a review of pattern matching techniques. The application areas for pattern matching are extensive, ranging from CAD systems to chemical analysis and from manufacturing to image processing. Published techniques and methods are classified and assessed within the context of three...... key issues: pattern classes, similiarity types and mathing methods. It has been shown that the techniques and approaches are as diverse and varied as the applications....

  10. Recommended approach to sofware development

    Science.gov (United States)

    Mcgarry, F. E.; Page, J.; Eslinger, S.; Church, V.; Merwarth, P.

    1983-01-01

    A set of guideline for an organized, disciplined approach to software development, based on data collected and studied for 46 flight dynamics software development projects. Methods and practices for each phase of a software development life cycle that starts with requirements analysis and ends with acceptance testing are described; maintenance and operation is not addressed. For each defined life cycle phase, guidelines for the development process and its management, and the products produced and their reviews are presented.

  11. URBAN MANAGEMENT– CURRENT STRATEGIC APPROACHES

    OpenAIRE

    Ruxandra-Irina POPESCU; Razvan-Andrei CORBOs

    2010-01-01

    In recent years urban management conceptual evolutions are more and more connected to the chances in public administration practice, in particular to ways of raising efficiency and effectiveness. The interest shared by a great number of stakeholders regarding urban development, the increasing role of environment issues and the need for a broad vision for managing cities, are all premises required for a strategic approach to urban management performance. The paper presents some relevant issues...

  12. Biotechnological approaches to rose breeding

    OpenAIRE

    Marchant, Robert

    1994-01-01

    The production of new rose cultivars by sexual crossing is problematic and time consuming due to sexual incompatibility. the failure of seeds to genninate. and to a limited gene pool. Biotechnology provides an obvious alternative for the creation of genetic novelty in rose. This thesis focuses on the development of novel approaches, based on embryo rescue, pollen cryopreservation, protoplast and transformation technologies. A reproducible embryo rescue technique was developed in which embr...

  13. Sociocultural epidemiology: an essential approach.

    Directory of Open Access Journals (Sweden)

    Paul Hersch-Martínez

    2013-09-01

    Full Text Available The necessity of an inclusive epidemiological approach, capable to attend the diverse dimensions involved in health damage as a reflective phenomenon of society is analyzed. The range of perspectives involved requires an inclusive methodological scope and applicative channels, in order to deal with sanitary realities systematically related to culture and social organization. Some constitutive elements of sociocultural epidemiology are underlined, shaping an operative proposal that can enhance the relationship between disciplines and sectors regarding specific outstanding public health problems.

  14. System Approach in RIPRAN Method

    Directory of Open Access Journals (Sweden)

    Branislav Lacko

    2017-06-01

    Full Text Available The article describes reasons, principles for design, structure and using of RIPRAN method (Risk Project Analysis for risk project analysis. The RIPRAN method is used to identify, quantify risks, and design proposals that reduce risk in the project to increase the likelihood of successful completion of the project. The method uses a system and process approach to risk analysis and respects international ISO standards that recommend how to perform a high‑quality risk analysis of the project. The method has been incorporated into the national standard of the Czech Republic among the recommended knowledge for certified project managers. The third version of the method is available. The method is included in teaching at many universities in the Czech Republic, trained by a number of training firms and used by firms to analyse the risks of corporate projects or by various risk analysis institutions for projects funded by the EU structural funds. The aim of the article is to inform about the RIPRAN method. At the same time, the paper points out that the method describes the procedure for risk analysis of the project and presents the benefits of RIPRAN application. The description of a system approach application when designing the RIPRAN method serves as an example of a system approach to risk engineering.

  15. Opening: Toward an Integrated Approach

    Directory of Open Access Journals (Sweden)

    Cheryl Geisler

    2016-02-01

    Full Text Available The rise of digital humanities has led many writing researchers to consider using digital tools to analyze rhetorical patterns in text. Yet taking a digital approach to the analysis of texts is a complex task. We are faced with a variety of techniques and tools, all of which require significant investment to learn and use. How can we best understand the costs and benefits of adopting a particular approach? Are they simply alternatives or can they be integrated? The three sets of authors in this special section attempt to address these questions by using alternative methodologies to analyze a common set of documents. The following opening piece serves as an introduction to the project. In it, we place their research in the context of taxonomy of approaches to text analysis, and review prior attempts at integration. Following the articles, a closing piece examines the prospects for integration. In it, we provide a brief review of the results of the analyses followed by an examination of their commonalities and variations. Finally, we conclude with the considerations that should be taken into account in choosing a method for textual analysis, as well as a discussion of the potential for an integration of methods.

  16. An abstract approach to music.

    Energy Technology Data Exchange (ETDEWEB)

    Kaper, H. G.; Tipei, S.

    1999-04-19

    In this article we have outlined a formal framework for an abstract approach to music and music composition. The model is formulated in terms of objects that have attributes, obey relationships, and are subject to certain well-defined operations. The motivation for this approach uses traditional terms and concepts of music theory, but the approach itself is formal and uses the language of mathematics. The universal object is an audio wave; partials, sounds, and compositions are special objects, which are placed in a hierarchical order based on time scales. The objects have both static and dynamic attributes. When we realize a composition, we assign values to each of its attributes: a (scalar) value to a static attribute, an envelope and a size to a dynamic attribute. A composition is then a trajectory in the space of aural events, and the complex audio wave is its formal representation. Sounds are fibers in the space of aural events, from which the composer weaves the trajectory of a composition. Each sound object in turn is made up of partials, which are the elementary building blocks of any music composition. The partials evolve on the fastest time scale in the hierarchy of partials, sounds, and compositions. The ideas outlined in this article are being implemented in a digital instrument for additive sound synthesis and in software for music composition. A demonstration of some preliminary results has been submitted by the authors for presentation at the conference.

  17. A possibilistic approach to clustering

    Science.gov (United States)

    Krishnapuram, Raghu; Keller, James M.

    1993-01-01

    Fuzzy clustering has been shown to be advantageous over crisp (or traditional) clustering methods in that total commitment of a vector to a given class is not required at each image pattern recognition iteration. Recently fuzzy clustering methods have shown spectacular ability to detect not only hypervolume clusters, but also clusters which are actually 'thin shells', i.e., curves and surfaces. Most analytic fuzzy clustering approaches are derived from the 'Fuzzy C-Means' (FCM) algorithm. The FCM uses the probabilistic constraint that the memberships of a data point across classes sum to one. This constraint was used to generate the membership update equations for an iterative algorithm. Recently, we cast the clustering problem into the framework of possibility theory using an approach in which the resulting partition of the data can be interpreted as a possibilistic partition, and the membership values may be interpreted as degrees of possibility of the points belonging to the classes. We show the ability of this approach to detect linear and quartic curves in the presence of considerable noise.

  18. Security Management – Systems Approach

    Directory of Open Access Journals (Sweden)

    Milan Kný

    2015-12-01

    Full Text Available The aim of the contribution is the use of the systems approach to treat security management as a practical field and new scientific discipline. The philosophy of systems approach to the solution of problems generally is an adequate methodological basis even for the theory of management. The path to the real optimization of security situation leads only through the holistic and solid solution. Applications of systems analysis and synthesis back up the fact, that systems approach and systems thinking should not absent in security objects. The truthfulness of the claim, that security management is a well-established discipline, depends on ongoing discussion that represents useful process of development of new scientific discipline. At the same time the rationality of science and systematism works as a counterbalance to irrational fear of the whole society, too. Which questions of security remain open in relation to „our interests“? Current problems of Europe should be solved systematically. It is necessary to define the space of interest (territorially the border of the EU or the Schengen area, to implement the system to the object with respect to the borders of the space, to specify the structure and subjects of decision making and implementation.

  19. Combined Approach for Solving the Electromagnetic Induction ...

    African Journals Online (AJOL)

    Nafiisah

    approaches to the reconstruction problem: the pixel-based approach and the parameter-based approach. This paper describes how both approaches may be combined for a more systematic reconstruction. Keywords: Electromagnetic induction, inverse problem, image reconstruction. *For correspondences and reprints ...

  20. Fuzzy multiple linear regression: A computational approach

    Science.gov (United States)

    Juang, C. H.; Huang, X. H.; Fleming, J. W.

    1992-01-01

    This paper presents a new computational approach for performing fuzzy regression. In contrast to Bardossy's approach, the new approach, while dealing with fuzzy variables, closely follows the conventional regression technique. In this approach, treatment of fuzzy input is more 'computational' than 'symbolic.' The following sections first outline the formulation of the new approach, then deal with the implementation and computational scheme, and this is followed by examples to illustrate the new procedure.

  1. Commercial dissemination approaches for solar home systems

    Energy Technology Data Exchange (ETDEWEB)

    Terrado, E.

    1997-12-01

    The author discusses the issue of providing solar home systems to primarily rural areas from the perspective of how to commercialize the process. He considers two different approaches, one an open market approach and the other an exclusive market approach. He describes examples of the exclusive market approach which are in process in Argentina and Brazil. Coming from a banking background, the business aspects are discussed in detail. He points out the strengths and weaknesses of both approaches toward developing such systems.

  2. Computational approaches for drug discovery.

    Science.gov (United States)

    Hung, Che-Lun; Chen, Chi-Chun

    2014-09-01

    Cellular proteins are the mediators of multiple organism functions being involved in physiological mechanisms and disease. By discovering lead compounds that affect the function of target proteins, the target diseases or physiological mechanisms can be modulated. Based on knowledge of the ligand-receptor interaction, the chemical structures of leads can be modified to improve efficacy, selectivity and reduce side effects. One rational drug design technology, which enables drug discovery based on knowledge of target structures, functional properties and mechanisms, is computer-aided drug design (CADD). The application of CADD can be cost-effective using experiments to compare predicted and actual drug activity, the results from which can used iteratively to improve compound properties. The two major CADD-based approaches are structure-based drug design, where protein structures are required, and ligand-based drug design, where ligand and ligand activities can be used to design compounds interacting with the protein structure. Approaches in structure-based drug design include docking, de novo design, fragment-based drug discovery and structure-based pharmacophore modeling. Approaches in ligand-based drug design include quantitative structure-affinity relationship and pharmacophore modeling based on ligand properties. Based on whether the structure of the receptor and its interaction with the ligand are known, different design strategies can be seed. After lead compounds are generated, the rule of five can be used to assess whether these have drug-like properties. Several quality validation methods, such as cost function analysis, Fisher's cross-validation analysis and goodness of hit test, can be used to estimate the metrics of different drug design strategies. To further improve CADD performance, multi-computers and graphics processing units may be applied to reduce costs. © 2014 Wiley Periodicals, Inc.

  3. [Causal analysis approaches in epidemiology].

    Science.gov (United States)

    Dumas, O; Siroux, V; Le Moual, N; Varraso, R

    2014-02-01

    Epidemiological research is mostly based on observational studies. Whether such studies can provide evidence of causation remains discussed. Several causal analysis methods have been developed in epidemiology. This paper aims at presenting an overview of these methods: graphical models, path analysis and its extensions, and models based on the counterfactual approach, with a special emphasis on marginal structural models. Graphical approaches have been developed to allow synthetic representations of supposed causal relationships in a given problem. They serve as qualitative support in the study of causal relationships. The sufficient-component cause model has been developed to deal with the issue of multicausality raised by the emergence of chronic multifactorial diseases. Directed acyclic graphs are mostly used as a visual tool to identify possible confounding sources in a study. Structural equations models, the main extension of path analysis, combine a system of equations and a path diagram, representing a set of possible causal relationships. They allow quantifying direct and indirect effects in a general model in which several relationships can be tested simultaneously. Dynamic path analysis further takes into account the role of time. The counterfactual approach defines causality by comparing the observed event and the counterfactual event (the event that would have been observed if, contrary to the fact, the subject had received a different exposure than the one he actually received). This theoretical approach has shown limits of traditional methods to address some causality questions. In particular, in longitudinal studies, when there is time-varying confounding, classical methods (regressions) may be biased. Marginal structural models have been developed to address this issue. In conclusion, "causal models", though they were developed partly independently, are based on equivalent logical foundations. A crucial step in the application of these models is the

  4. Approach to Mars Field Geology

    Science.gov (United States)

    Muehlberger, William; Rice, James W.; Parker, Timothy; Lipps, Jere H.; Hoffman, Paul; Burchfiel, Clark; Brasier, Martin

    1998-01-01

    The goals of field study on Mars are nothing less than to understand the processes and history of the planet at whatever level of detail is necessary. A manned mission gives us an unprecedented opportunity to use the immense power of the human mind to comprehend Mars in extraordinary detail. To take advantage of this opportunity, it is important to examine how we should approach the field study of Mars. In this effort, we are guided by over 200 years of field exploration experience on Earth as well as six manned missions exploring the Moon.

  5. Location theory a unified approach

    CERN Document Server

    Nickel, Stefan

    2006-01-01

    Although modern location theory is now more than 90 years old, the focus of researchers in this area has been mainly problem oriented. However, a common theory, which keeps the essential characteristics of classical location models, is still missing.This monograph addresses this issue. A flexible location problem called the Ordered Median Problem (OMP) is introduced. For all three main subareas of location theory (continuous, network and discrete location) structural properties of the OMP are presented and solution approaches provided. Numerous illustrations and examples help the reader to bec

  6. Nanothermodynamics: a subdivision potential approach

    Directory of Open Access Journals (Sweden)

    R. Moussavi

    2005-12-01

    Full Text Available  Classical thermodynamic laws and relations have been developed for macroscopic systems that satisfy the thermodynamic limit. These relations are challenged as the system size decreases to the scale of nano-systems, in which thermodynamic properties are overshadowed by system size, and the usual classical concepts of extensivity and intensivity are no longer valid. The challenges to the classical thermodynamics in relation to small systems are demonstrated, and via the approach introduced by Hill, the concept of sub-division potential is clarified in details. The fundamental thermodynamic relations are obtained using a rational-based method.

  7. The calculus a genetic approach

    CERN Document Server

    Toeplitz, Otto

    2007-01-01

    When first published posthumously in 1963, this book presented a radically different approach to the teaching of calculus.  In sharp contrast to the methods of his time, Otto Toeplitz did not teach calculus as a static system of techniques and facts to be memorized. Instead, he drew on his knowledge of the history of mathematics and presented calculus as an organic evolution of ideas beginning with the discoveries of Greek scholars, such as Archimedes, Pythagoras, and Euclid, and developing through the centuries in the work of Kepler, Galileo, Fermat, Newton, and Leibniz. Through this unique a

  8. Microfluidic Approach to Cell Microencapsulation.

    Science.gov (United States)

    Sharma, Varna; Hunckler, Michael; Ramasubramanian, Melur K; Opara, Emmanuel C; Katuri, Kalyan C

    2017-01-01

    Bioartificial pancreas made of insulin-secreting islets cells holds great promise in the treatment of individuals with Type-1 diabetes. Successful islet cell microencapsulation in biopolymers is a key step for providing immunoisolation of transplanted islet cells. Because of the variability in the size and shape of pancreatic islets, one of the main obstacles in their microencapsulation is the inability to consistently control shape, size, and microstructure of the encapsulating biopolymer capsule. In this chapter, we provide a detailed description of a microfluidic approach to islet cell encapsulation in alginate that might address the microencapsulation challenges.

  9. Gene Therapy Approaches to Hemoglobinopathies.

    Science.gov (United States)

    Ferrari, Giuliana; Cavazzana, Marina; Mavilio, Fulvio

    2017-10-01

    Gene therapy for hemoglobinopathies is currently based on transplantation of autologous hematopoietic stem cells genetically modified with a lentiviral vector expressing a globin gene under the control of globin transcriptional regulatory elements. Preclinical and early clinical studies showed the safety and potential efficacy of this therapeutic approach as well as the hurdles still limiting its general application. In addition, for both beta-thalassemia and sickle cell disease, an altered bone marrow microenvironment reduces the efficiency of stem cell harvesting as well as engraftment. These hurdles need be addressed for gene therapy for hemoglobinopathies to become a clinical reality. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Hemorrhagic shock: The "physiology approach"

    Directory of Open Access Journals (Sweden)

    Fabrizio Giuseppe Bonanno

    2012-01-01

    Full Text Available A shift of approach from ′clinics trying to fit physiology′ to the one of ′physiology to clinics′, with interpretation of the clinical phenomena from their physiological bases to the tip of the clinical iceberg, and a management exclusively based on modulation of physiology, is finally surging as the safest and most efficacious philosophy in hemorrhagic shock. ATLS® classification and recommendations on hemorrhagic shock are not helpful because antiphysiological and potentially misleading. Hemorrhagic shock needs to be reclassified in the direction of usefulness and timing of intervention: in particular its assessment and management need to be tailored to physiology.

  11. Cognitive reasoning a formal approach

    CERN Document Server

    Anshakov, Oleg M

    2010-01-01

    Dealing with uncertainty, moving from ignorance to knowledge, is the focus of cognitive processes. Understanding these processes and modelling, designing, and building artificial cognitive systems have long been challenging research problems. This book describes the theory and methodology of a new, scientifically well-founded general approach, and its realization in the form of intelligent systems applicable in disciplines ranging from social sciences, such as cognitive science and sociology, through natural sciences, such as life sciences and chemistry, to applied sciences, such as medicine,

  12. Two Approaches to Entrepreneurship Education

    DEFF Research Database (Denmark)

    Moberg, Kåre

    2014-01-01

    and focuses on fostering non-cognitive entrepreneurial skills. Furthermore, the role of supportive teaching styles and action-based teaching methods in entrepreneurship education at this level of education is investigated. The analysis is based on data from two surveys including 801 randomly selected Danish...... an alternative way to assess educational dimensions (content and teaching methods) separately.......The objective of this paper is to analyse the influence of two different approaches to entrepreneurship education at the lower secondary level of education. The influence of education for entrepreneurship and education through entrepreneurship on pupils' level of school engagement...

  13. Educational approaches for discouraging plagiarism.

    Science.gov (United States)

    Fischer, Beth A; Zigmond, Michael J

    2011-01-01

    Suggested approaches to reduce the occurrence of plagiarism in academia, particularly among trainees. These include (1) educating individuals as to the definition of plagiarism and its consequences through written guidelines, active discussions, and practice in identifying proper and improper citation practices; (2) distributing checklists that break the writing task into more manageable steps, (3) requiring the submission of an outline and then a first draft prior to the deadline for a paper; (4) making assignments relevant to individual interests; and (5) providing trainees with access to software programs that detect plagiarism. Copyright © 2011 Elsevier Inc. All rights reserved.

  14. Algebraic Approach to Algorithmic Logic

    Directory of Open Access Journals (Sweden)

    Bancerek Grzegorz

    2014-09-01

    Full Text Available We introduce algorithmic logic - an algebraic approach according to [25]. It is done in three stages: propositional calculus, quantifier calculus with equality, and finally proper algorithmic logic. For each stage appropriate signature and theory are defined. Propositional calculus and quantifier calculus with equality are explored according to [24]. A language is introduced with language signature including free variables, substitution, and equality. Algorithmic logic requires a bialgebra structure which is an extension of language signature and program algebra. While-if algebra of generator set and algebraic signature is bialgebra with appropriate properties and is used as basic type of algebraic logic.

  15. Unified approach to dense matter

    Energy Technology Data Exchange (ETDEWEB)

    Park, Byung-Yoon [CSSM, University of Adelaide, Adelaide 5005 (Australia); Lee, Hee-Jung [Departament de Fisica Teorica and Institut de Fisica Corpuscular Universitat de Valencia and Consejo Superior de Investigaciones Cientificas, E-46100 Burjassot (Valencia) (Spain); Vento, Vicente [Departament de Fisica Teorica and Institut de Fisica Corpuscular Universitat de Valencia and Consejo Superior de Investigaciones Cientificas, E-46100 Burjassot (Valencia) (Spain); Kim, Joon-Il [Department of Physics, Seoul National University, Seoul 151-742 (Korea, Republic of); Min, Dong-Pil [Department of Physics, Seoul National University, Seoul 151-742 (Korea, Republic of); Rho, Mannque [Department of Physics, Hanyang University, Seoul 133-791, Korea, and Service de Physique Theorique, CE Saclay, 91191 Gif-sur-Yvette (France)

    2005-04-15

    We apply the Skyrme model to dense hadronic matter, which provides a unified approach to high density, valid in the large N {sub c} limit. In our picture, dense hadronic matter is described by the classical soliton configuration with minimum energy for the given baryon number density. By incorporating the meson fluctuations on such ground state we obtain an effective Lagrangian for meson dynamics in a dense medium. Our starting point has been the Skyrme model defined in terms of pions, thereafter we have extended and improved the model by incorporating other degrees of freedom such as dilaton, kaons and vector mesons.

  16. Real Analysis A Historical Approach

    CERN Document Server

    Stahl, Saul

    2011-01-01

    A provocative look at the tools and history of real analysis This new edition of Real Analysis: A Historical Approach continues to serve as an interesting read for students of analysis. Combining historical coverage with a superb introductory treatment, this book helps readers easily make the transition from concrete to abstract ideas. The book begins with an exciting sampling of classic and famous problems first posed by some of the greatest mathematicians of all time. Archimedes, Fermat, Newton, and Euler are each summoned in turn, illuminating the utility of infinite, power, and trigonome

  17. A geometric approach to complexity.

    Science.gov (United States)

    Ay, Nihat; Olbrich, Eckehard; Bertschinger, Nils; Jost, Jürgen

    2011-09-01

    We develop a geometric approach to complexity based on the principle that complexity requires interactions at different scales of description. Complex systems are more than the sum of their parts of any size and not just more than the sum of their elements. Using information geometry, we therefore analyze the decomposition of a system in terms of an interaction hierarchy. In mathematical terms, we present a theory of complexity measures for finite random fields using the geometric framework of hierarchies of exponential families. Within our framework, previously proposed complexity measures find their natural place and gain a new interpretation.

  18. 'Lean' approach gives greater efficiency.

    Science.gov (United States)

    Call, Roger

    2014-02-01

    Adapting the 'Lean' methodologies used for many years by many manufacturers on the production line - such as in the automotive industry - and deploying them in healthcare 'spaces' can, Roger Call, an architect at Herman Miller Healthcare in the US, argues, 'easily remedy many of the inefficiencies' found within a healthcare facility. In an article that first appeared in the September 2013 issue of The Australian Hospital Engineer, he explains how 'Lean' approaches such as the 'Toyota production system', and 'Six Sigma', can be harnessed to good effect in the healthcare sphere.

  19. HEDR modeling approach: Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Shipler, D.B.; Napier, B.A.

    1994-05-01

    This report is a revision of the previous Hanford Environmental Dose Reconstruction (HEDR) Project modeling approach report. This revised report describes the methods used in performing scoping studies and estimating final radiation doses to real and representative individuals who lived in the vicinity of the Hanford Site. The scoping studies and dose estimates pertain to various environmental pathways during various periods of time. The original report discussed the concepts under consideration in 1991. The methods for estimating dose have been refined as understanding of existing data, the scope of pathways, and the magnitudes of dose estimates were evaluated through scoping studies.

  20. Computer Networks A Systems Approach

    CERN Document Server

    Peterson, Larry L

    2011-01-01

    This best-selling and classic book teaches you the key principles of computer networks with examples drawn from the real world of network and protocol design. Using the Internet as the primary example, the authors explain various protocols and networking technologies. Their systems-oriented approach encourages you to think about how individual network components fit into a larger, complex system of interactions. Whatever your perspective, whether it be that of an application developer, network administrator, or a designer of network equipment or protocols, you will come away with a "big pictur

  1. Computational approaches to energy materials

    CERN Document Server

    Catlow, Richard; Walsh, Aron

    2013-01-01

    The development of materials for clean and efficient energy generation and storage is one of the most rapidly developing, multi-disciplinary areas of contemporary science, driven primarily by concerns over global warming, diminishing fossil-fuel reserves, the need for energy security, and increasing consumer demand for portable electronics. Computational methods are now an integral and indispensable part of the materials characterisation and development process.   Computational Approaches to Energy Materials presents a detailed survey of current computational techniques for the

  2. Chemoselective approaches to glycoprotein assembly

    Energy Technology Data Exchange (ETDEWEB)

    Hang, Howard C.; Bertozzi, Carolyn R.

    2001-02-23

    Oligosaccharides on proteins and lipids play central roles in human health and disease. The molecular analysis of glycoconjugate function has benefited tremendously from new methods for their chemical synthesis, which provides homogeneous material not attainable from biosynthetic systems. Still, glycoconjugate synthesis requires the manipulation of multiple stereocenters and protecting groups and remains the domain of a few expert laboratories around the world. This account summarizes chemoselective approaches for assembling homogeneous glycoconjugates that attempt to reduce the barriers to their synthesis. The objective of these methods is to make glycoconjugate synthesis accessible to a broader community, thereby accelerating progress in glycobiology.

  3. Operational gaming an international approach

    CERN Document Server

    Ståhl, Ingolf

    1983-01-01

    Operational Gaming: An International Approach focuses on various research on this method of systems analysis. The text points out the value of this method in decision making, planning, and in the implementation of policies. The book presents a survey that highlights the connection of experimental gaming, game theory, and operational gaming. The value of gaming as a balancing method in assessing multifaceted computer models, most notably about their assumptions on human behavior, is noted. The book also offers an overview of gaming in other countries, such as Bulgaria, Soviet Union, and Japan,

  4. Enamel microabrasion: a new approach.

    Science.gov (United States)

    Croll, T P; Helpin, M L

    2000-01-01

    Enamel microabrasion is a proven method of removing superficial intrinsic enamel discoloration defects. The method is safe, easily performed, and causes no discomfort for the patient. A new commercially available microabrasion system has been introduced by Ultradent Products Inc. In addition, a new tooth isolation material is available, along with a visible light-activated in-office hydrogen peroxide solution. This article describes these new products and documents tooth-color correction for two young patients using this new tooth-color correction approach.

  5. Experimental design a chemometric approach

    CERN Document Server

    Deming, SN

    1987-01-01

    Now available in a paperback edition is a book which has been described as ``...an exceptionally lucid, easy-to-read presentation... would be an excellent addition to the collection of every analytical chemist. I recommend it with great enthusiasm.'' (Analytical Chemistry). Unlike most current textbooks, it approaches experimental design from the point of view of the experimenter, rather than that of the statistician. As the reviewer in `Analytical Chemistry' went on to say: ``Deming and Morgan should be given high praise for bringing the principles of experimental design to the level of the p

  6. BEHIND THE CHANGING OF LANGUAGE TEACHING APPROACHES

    Directory of Open Access Journals (Sweden)

    Anak Agung Sagung Shanti Sari Dewi

    2015-05-01

    Full Text Available The history has noted that the emergence of various approcahes towards foreign language learning is to search for the most effective and efficient way in teaching foreign languages that should match the development and change in the world. Before the Communicative Language Approach was widely known and considered by many as the best approach in foreign language teaching, there have also been other approaches around, which emerged in accordance with the development of particular period. Those approaches are Grammar Translation Approach, Dirext Method, Reading Approach, Audio Lingual Aproach dan Cognitive Approach. At the present times, with the advance of technology, language teaching seems to adapt itslef to that development. CALL approach as one of the computer-based approaches to foreign language teaching is considered to be effective to achieve success in foreign language learning.

  7. Approach/avoidance in dreams.

    Science.gov (United States)

    Malcolm-Smith, Susan; Koopowitz, Sheri; Pantelis, Eleni; Solms, Mark

    2012-03-01

    The influential threat simulation theory (TST) asserts that dreaming yields adaptive advantage by providing a virtual environment in which threat-avoidance may be safely rehearsed. We have previously found the incidence of biologically threatening dreams to be around 20%, with successful threat avoidance occurring in approximately one-fifth of such dreams. TST asserts that threat avoidance is over-represented relative to other possible dream contents. To begin assessing this issue, we contrasted the incidence of 'avoidance' dreams with that of their opposite: 'approach' dreams. Because TST states that the threat-avoidance function is only fully activated in ecologically valid (biologically threatening) contexts, we also performed this contrast for populations living in both high- and low-threat environments. We find that 'approach' dreams are significantly more prevalent across both contexts. We suggest these results are more consistent with the view that dreaming is generated by reward-seeking systems than by fear-conditioning systems, although reward-seeking is clearly not the only factor determining the content of dreams. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. Interdisciplinary Approach in Engineering Education

    Directory of Open Access Journals (Sweden)

    Anda Zeidmane

    2011-04-01

    Full Text Available The analysis of the scientific literature available on the types of general competences and their classification caused the authors to conclude that it is necessary to implement interdisciplinary approach in engineering education to develop competences necessary for engineers to make them competitive in the labour market. The attention should be paid to a professional foreign language, computer literacy and educational psychology recommendations. To improve professional foreign language skills, CLIL (Content and Language Integrated Learning method should be integrated in the study process of engineering education. In order to develop information literacy competence, it is important to create a single e-study environment. The academic staff, developing study subjects for engineering programmes, should focus on the study content and study methods. As regards the content, the compromise should be sought between fundamental acquisition of the knowledge of the subject matter, the know-how of the application of this knowledge as well as the use of brand new software in the calculations. The paper presents the examples of the application of the interdisciplinary approach in the universities, where the authors of the paper are affiliated: the LUA (Latvia University of Agriculture and the RTU (Riga Technical University, respectively.

  9. Modeling Approaches in Planetary Seismology

    Science.gov (United States)

    Weber, Renee; Knapmeyer, Martin; Panning, Mark; Schmerr, Nick

    2014-01-01

    Of the many geophysical means that can be used to probe a planet's interior, seismology remains the most direct. Given that the seismic data gathered on the Moon over 40 years ago revolutionized our understanding of the Moon and are still being used today to produce new insight into the state of the lunar interior, it is no wonder that many future missions, both real and conceptual, plan to take seismometers to other planets. To best facilitate the return of high-quality data from these instruments, as well as to further our understanding of the dynamic processes that modify a planet's interior, various modeling approaches are used to quantify parameters such as the amount and distribution of seismicity, tidal deformation, and seismic structure on and of the terrestrial planets. In addition, recent advances in wavefield modeling have permitted a renewed look at seismic energy transmission and the effects of attenuation and scattering, as well as the presence and effect of a core, on recorded seismograms. In this chapter, we will review these approaches.

  10. Snow metamorphism: A fractal approach

    Science.gov (United States)

    Carbone, Anna; Chiaia, Bernardino M.; Frigo, Barbara; Türk, Christian

    2010-09-01

    Snow is a porous disordered medium consisting of air and three water phases: ice, vapor, and liquid. The ice phase consists of an assemblage of grains, ice matrix, initially arranged over a random load bearing skeleton. The quantitative relationship between density and morphological characteristics of different snow microstructures is still an open issue. In this work, a three-dimensional fractal description of density corresponding to different snow microstructure is put forward. First, snow density is simulated in terms of a generalized Menger sponge model. Then, a fully three-dimensional compact stochastic fractal model is adopted. The latter approach yields a quantitative map of the randomness of the snow texture, which is described as a three-dimensional fractional Brownian field with the Hurst exponent H varying as continuous parameters. The Hurst exponent is found to be strongly dependent on snow morphology and density. The approach might be applied to all those cases where the morphological evolution of snow cover or ice sheets should be conveniently described at a quantitative level.

  11. Neural Approaches to Machine Consciousness

    Science.gov (United States)

    Aleksander, Igor; Eng., F. R.

    2008-10-01

    `Machine Consciousness', which some years ago might have been suppressed as an inappropriate pursuit, has come out of the closet and is now a legitimate area of research concern. This paper briefly surveys the last few years of worldwide research in this area which divides into rule-based and neural approaches and then reviews the work of the author's laboratory during the last ten years. The paper develops a fresh perspective on this work: it is argued that neural approaches, in this case, digital neural systems, can address phenomenological consciousness. Important clarifications of phenomenology and virtuality which enter this modelling are explained in the early parts of the paper. In neural models, phenomenology is a form of depictive inner representation that has five specific axiomatic features: a sense of self-presence in an external world; a sense of imagination of past experience and fiction; a sense of attention; a capacity for planning; a sense of emotion-based volition that influences planning. It is shown that these five features have separate but integrated support in dynamic neural systems.

  12. Improving immunization approaches to cholera.

    Science.gov (United States)

    Saha, Amit; Rosewell, Alexander; Hayen, Andrew; MacIntyre, C Raina; Qadri, Firdausi

    2017-03-01

    Cholera's impact is greatest in resource-limited countries. In the last decade several large epidemics have led to a global push to improve and implement the tools for cholera prevention and control. Areas covered: PubMed, Google Scholar and the WHO website were searched to review the literature and summarize the current status of cholera vaccines to make recommendations on improving immunization approaches to cholera. Oral cholera vaccines (OCVs) have demonstrated their effectiveness in endemic, outbreak response and emergency settings, highlighting their potential for wider adoption. While two doses of the currently available OCVs are recommended by manufacturers, a single dose would be easier to implement. Encouragingly, recent studies have shown that cold chain requirements may no longer be essential. The establishment of the global OCV stockpile in 2013 has been a major advance in cholera preparedness. New killed and live-attenuated vaccines are being actively explored as candidate vaccines for endemic settings and/or as a traveller's vaccine. The recent advances in cholera vaccination approaches should be considered in the global cholera control strategy. Expert commentary: The development of affordable cholera vaccines is a major success to improve cholera control. New vaccines and country specific interventions will further reduce the burden of this disease globally.

  13. Robotic approaches to prolapse surgery.

    Science.gov (United States)

    Rosenblum, Nirit

    2012-07-01

    Pelvic reconstructive surgeons in the fields of urology, gynecology and urogynecology have continually adapted new techniques in pelvic organ prolapse (POP) repair in order to improve both anatomic and subjective outcomes. In the last 5 years, robotic surgery has gained a strong foothold in urologic oncology, gynecologic oncology, cardiothoracic surgery and now in female pelvic medicine. Robotic surgery has made its way into the armamentarium of POP treatment and has allowed pelvic surgeons to adapt the 'gold standard' technique of abdominal sacrocolpopexy to a minimally invasive approach with improved intraoperative morbidity and decreased convalescence. This review article aims to discuss the techniques of robotic prolapse repair as well as morbidity, cost and clinical outcomes. The adaptation of minimally invasive approaches to the treatment of POP initially began with laparoscopy, something only those surgeons with extensive and advanced laparoscopic skills are able to accomplish. Access to robotic technology makes conversion from open or laparoscopic to robotic surgery much more feasible for most pelvic floor surgeons. There are currently no published randomized, controlled trials comparing robotic with open or laparoscopic sacrocolpopexy, however, there are several publications reporting both retrospective and prospective series of women undergoing robotic-assisted sacrocolpopexy. Robotic-assisted pelvic floor surgery has become an important component of the pelvic surgeon's armamentarium in the treatment of symptomatic POP. Those pelvic surgeons without significant expertise in laparoscopy required for sacral dissection and intracorporeal suturing can readily learn the necessary techniques required for robotic surgery.

  14. Approaching Bose-Einstein condensation

    Energy Technology Data Exchange (ETDEWEB)

    Ferrari, Loris, E-mail: loris.ferrari@unibo.it [Department of Physics of the University, Viale B. Pichat, 6/2, 40127, Bologna (Italy)

    2011-11-15

    Bose-Einstein condensation (BEC) is discussed at the level of an advanced course of statistical thermodynamics, clarifying some formal and physical aspects that are usually not covered by the standard pedagogical literature. The non-conventional approach adopted starts by showing that the continuum limit, in certain cases, cancels out the crucial role of the bosonic ground level. If so, a correct treatment of the problem, including the ground level population N{sub 0} by construction, leads to BEC in a straightforward way. For a density of states of the form G({epsilon}){approx}{epsilon}{sup {gamma}}, the chemical potential {mu} is explicitly calculated as a function of the temperature T and of the number N of bosons, for various significant values of the positive exponent {gamma}. In the thermodynamic limit, in which the boson number N diverges and BEC is a sharp process, the chemical potential {mu} is a singular function of T at the critical temperature T{sub B}, determined by an appropriate critical exponent. The condensate population N{sub 0} is studied analytically and numerically as a function of the temperature, for various values of N and for different {gamma}. This provides an accurate description of the way BEC approaches the character of a sharp phase transition. Some aspects of the real experiments on BEC, involving a finite number of bosons, are also illustrated.

  15. Shore approach of Camarupim pipeline

    Energy Technology Data Exchange (ETDEWEB)

    Bernardi, Tiaraju P.; Oliveira Neto, Vasco A. de; Siqueira, Jakson [Petroleo Brasileiro S.A. (PETROBRAS), Rio de Janeiro, RJ (Brazil)

    2009-07-01

    Camarupim Field is located in the northern portion of Espirito Santo Basin and was discovered from the drilling of the well 1-ESS-164 in 2006. It is a gas field which start of the production is in mid of 2009. The production unit will be a FPSO (Floating Production, Storage and Offloading) and the gas will flow through a pipeline with diameter ranging from 12 inches and 24 inches with approximately 60 km long, from the FPSO Cidade de Sao Mateus to UTGC (Unit for Treatment of Gas Cacimbas-Linhares-ES). The FPSO will have processing capacity of 10MMm3/day of gas. Due to the approach of the pipeline in the continental portion, located in an environmental protection area and place of spawning of sea turtles, the connection between the stretch of sea and land pipeline running through a shore approach, known and proven technique of horizontal directional drilling about 950m in length. This paper will be shown the assumptions adopted, the technique employed, the challenges faced by the team and the lessons learned to build the directional hole. (author)

  16. Approach to Rectal Cancer Surgery

    Directory of Open Access Journals (Sweden)

    Terence C. Chua

    2012-01-01

    Full Text Available Rectal cancer is a distinct subset of colorectal cancer where specialized disease-specific management of the primary tumor is required. There have been significant developments in rectal cancer surgery at all stages of disease in particular the introduction of local excision strategies for preinvasive and early cancers, standardized total mesorectal excision for resectable cancers incorporating preoperative short- or long-course chemoradiation to the multimodality sequencing of treatment. Laparoscopic surgery is also increasingly being adopted as the standard rectal cancer surgery approach following expertise of colorectal surgeons in minimally invasive surgery gained from laparoscopic colon resections. In locally advanced and metastatic disease, combining chemoradiation with radical surgery may achieve total eradication of disease and disease control in the pelvis. Evidence for resection of metastases to the liver and lung have been extensively reported in the literature. The role of cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for peritoneal metastases is showing promise in achieving locoregional control of peritoneal dissemination. This paper summarizes the recent developments in approaches to rectal cancer surgery at all these time points of the disease natural history.

  17. A new approach to magic

    Directory of Open Access Journals (Sweden)

    Čvorović Jelena

    2006-01-01

    Full Text Available This paper uses the example of traditional practices of magic to suggest ways to incorporate cultural behaviors within the evolutionary paradigm. The first suggestion is to restrict hypotheses to only identifiable variables. This means avoiding the temptation of following the nonevolutionary social sciences in the practice of basing explanations on unverifiable guesses about what beliefs (or memes in evolutionary jargon may or may not inhabit people's brains. In contrast with previous explanations that magical practices result from beliefs and memes whose primarily purpose is to reduce anxiety, we propose that magic is a form of communication that promotes cooperation and often avoids anti-social behavior. This effect of increased cooperation could explain why traditional forms of magic have probably existed and had significant positive consequences for the participants. To be effective as a means of communication, magical rituals must specify both the content of the message and the receiver of the message. Although the content of the communicative message differs with different types of magic, all magical acts serve a purpose to influence the behavior of the party involved and that is the most significant identifiable effect of such behavior. An advantage of this approach over many previous explanations of magic is that because it focuses on identifiable phenomena, the definitions and explanations used in this approach can be falsified.

  18. The ethnoprimatological approach in primatology.

    Science.gov (United States)

    Fuentes, Agustin; Hockings, Kimberley J

    2010-09-01

    Recent and long-term sympatries between humans and nonhuman primates (hereafter primates) are central to the behavioral ecology, conservation, and evolutionary trajectories of numerous primate species. Ethnoprimatology emphasizes that interconnections between humans and primates should be viewed as more than just disruptions of a "natural" state, and instead anthropogenic contexts must be considered as potential drivers for specific primate behavioral patterns. Rather than focusing solely on the behavior and ecology of the primate species at hand, as in traditional primatology, or on the symbolic meanings and uses of primates, as in socio-cultural anthropology, ethnoprimatology attempts to merge these perspectives into a more integrative approach. As human pressures on environments continue to increase and primate habitats become smaller and more fragmented, the need for a primatology that considers the impact of human attitudes and behavior on all aspects of primate lives and survival is imperative. In this special issue, we present both data-driven examples and more general discussions that describe how ethnoprimatological approaches can be both a contribution to the core theory and practice of primatology and a powerful tool in our goal of conservation action. 2010 Wiley-Liss, Inc.

  19. Systematic approach to thermal leptogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Frossard, T.; Kartavtsev, A. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Garny, M. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Hohenegger, A. [Ecole Polytechnique Federale de Lausanne, LPPC, BSP (Switzerland); Mitrouskas, D. [Muenchen Univ. (Germany)

    2012-11-15

    In this work we study thermal leptogenesis using non-equilibrium quantum field theory. Starting from fundamental equations for correlators of the quantum fields we describe the steps necessary to obtain quantum kinetic equations for quasiparticles. These can easily be compared to conventional results and overcome conceptional problems inherent in the canonical approach. Beyond CP-violating decays we include also those scattering processes which are tightly related to the decays in a consistent approximation of fourth order in the Yukawa couplings. It is demonstrated explicitly how the S-matrix elements for the scattering processes in the conventional approach are related to two- and three-loop contributions to the effective action. We derive effective decay and scattering amplitudes taking medium corrections and thermal masses into account. In this context we also investigate CP-violating Higgs decay within the same formalism. From the kinetic equations we derive rate equations for the lepton asymmetry improved in that they include quantum-statistical effects and medium corrections to the quasiparticle properties.

  20. Current approach to liver traumas.

    Science.gov (United States)

    Kaptanoglu, Levent; Kurt, Necmi; Sikar, Hasan Ediz

    2017-03-01

    Liver injuries remain major obstacle for successful treatment, due to size and location of the liver. Requirement for surgery should be determined by clinical factors, most notably hemodynamical state. In this present study we tried to declare our approach to liver traumas. We also tried to emphasize the importance of conservative treatment, since surgeries for liver traumas carry high mortality rates. Patients admitted to the Department of Emergency Surgery at Kartal Research and Education Hospital, due to liver trauma were retrospectively analyzed between 2003 and 2013. Patient demographics, hepatic panel, APTT (activated partial thromboplastin time), PT (prothrombin time), INR (international normalized ratio), fibrinogen, biochemistry panel were recorded. Hemodynamic instability was the most prominent factor for surgery decision, in the lead of current Advanced Trauma Life Support (ATLS) protocols. Operation records and imaging modalities revealed liver injuries according to the Organ Injury Scale of the American Association for the Surgery of Trauma. 300 patients admitted to emergency department were included in our study (187 males and 113 females). Mean age was 47 years (range, 12-87). The overall mortality rate was 13% (40 out of 300). Major factor responsible for mortality rates and outcome was stability of cases on admission. 188 (% 63) patients were counted as stable, whereas 112 (% 37) cases were found unstable (blood pressure ≤ 90, after massive resuscitation). 192 patients were observed conservatively, whereas 108 cases received abdominal surgery. High levels of AST, ALT, LDH, INR, creatinine and low levels of fibrinogen and low platelet counts on admission were found to be associated with mortality and these cases also had Grade 4 and 5 injuries. Hemodynamic instability on admission and the type and grade of injury played major role in mortality rates). Packing was performed in 35 patients, with Grade 4 and 5 injuries. Mortality rate was %13 (40

  1. Hydrogeological challenges through gender approaches

    Science.gov (United States)

    Di Lorenzo, Maria Rosaria; Saltari, Davide; Di Giacomo, Tullia Valeria

    2017-04-01

    Women and Men play a different role in the society, tied from the differences (physical, biological, somatic, etc…) typical of each one. In the last decades, more gender approach has been introduced in a number of fields including the hydrogeological risk. Experiences, needs and potential of each one, women and men, covers both the risk reduction before the occurrence of extreme events (vulnerability assessment and prediction of the expected risk), then in the next emergency and intervention in follow-up actions to the overcoming of the event for the return to everyday life. The response of the extreme hydrological events are also subordinated from gender participation and it is closely related from other aspects, as natural disasters (flood events), gender inequalities and urban floodings. These aspects are also scheduled by the different approaches: a woman focuses different primary and social aspects than a man. How women can help organizations offering new 'policies' and government is the main aspect to be considered and how a gender approach can mitigate disasters to hydrological risk. It depends on some factors: gender inequalities (gender perception and sensibility), importance of natural disasters and urban floodings. Gender inequalities can match both in the natural disasters and urban floodings in a relevant way. ICT solutions can also give a helpful framework to accelerate and focus the quicker condition to get the better approach and solution. Gender has a particular significant, explanatory variable in disaster research. Many studies, show how women have higher mortality and morbidity rates than men during natural disasters, especially in lower income countries. In the aftermath disasters, at the same time, specific responsibilities on women are imposed from the gendered division of labour. Furthermore gender differences are sometimes attributed to traditional women's roles, discrimination, lower physical strength, nutritional deficiencies, etc. as

  2. Computer architecture a quantitative approach

    CERN Document Server

    Hennessy, John L

    2019-01-01

    Computer Architecture: A Quantitative Approach, Sixth Edition has been considered essential reading by instructors, students and practitioners of computer design for over 20 years. The sixth edition of this classic textbook is fully revised with the latest developments in processor and system architecture. It now features examples from the RISC-V (RISC Five) instruction set architecture, a modern RISC instruction set developed and designed to be a free and openly adoptable standard. It also includes a new chapter on domain-specific architectures and an updated chapter on warehouse-scale computing that features the first public information on Google's newest WSC. True to its original mission of demystifying computer architecture, this edition continues the longstanding tradition of focusing on areas where the most exciting computing innovation is happening, while always keeping an emphasis on good engineering design.

  3. Therapeutic approaches for celiac disease

    Science.gov (United States)

    Plugis, Nicholas M.; Khosla, Chaitan

    2015-01-01

    Celiac disease is a common, lifelong autoimmune disorder for which dietary control is the only accepted form of therapy. A strict gluten-free diet is burdensome to patients and can be limited in efficacy, indicating there is an unmet need for novel therapeutic approaches to supplement or supplant dietary therapy. Many molecular events required for disease pathogenesis have been recently characterized and inspire most current and emerging drug-discovery efforts. Genome-wide association studies (GWAS) confirm the importance of human leukocyte antigen genes in our pathogenic model and identify a number of new risk loci in this complex disease. Here, we review the status of both emerging and potential therapeutic strategies in the context of disease pathophysiology. We conclude with a discussion of how genes identified during GWAS and follow-up studies that enhance susceptibility may offer insight into developing novel therapies. PMID:26060114

  4. Waste Characterization: Approaches and Methods

    DEFF Research Database (Denmark)

    Lagerkvist, A.; Ecke, H.; Christensen, Thomas Højlund

    2011-01-01

    Characterization of solid waste is usually a difficult task because of the heterogeneity of the waste and its spatial as well as temporal variations. This makes waste characterization costly if good and reliable data with reasonable uncertainty is to be obtained. Therefore, a waste characterization...... is often narrowly defined to meet specific needs for information. This may however limit the general usefulness of the information gained, for example, if the specific purpose limited the characterization to a subset of variables. In general, data available in the solid waste area are limited and often...... with limited representation. This chapter describes common approaches and methods in waste characterization including common terms, sampling, characterization methods and data evaluation. The focus is on the characterization of waste as it is generated or collected, while specific issues on characterization...

  5. A Dialogic Approach to Pragmatics

    Directory of Open Access Journals (Sweden)

    Иштван Кечкеш

    2016-12-01

    Full Text Available This paper focuses on how the limits of pragmatics - as long as it is restricted to the analysis of one utterance at a time - are overcome by including the hearer not only as interpreter who tries to understand the speaker’s utterance but as an interlocutor who tries to come to an understanding with the speaker. The goal of the paper is not to describe and analyze the dialogue approach rather explain what inner developments in the pragmatics paradigm have made it necessary to move in a dialogic direction, specifically emphasizing the importance of evaluating speaker meaning from the perspective of the speaker rather than from the perspective of the hearer and the double role of the interlocutor (speaker-hearer.

  6. A programming approach to computability

    CERN Document Server

    Kfoury, A J; Arbib, Michael A

    1982-01-01

    Computability theory is at the heart of theoretical computer science. Yet, ironically, many of its basic results were discovered by mathematical logicians prior to the development of the first stored-program computer. As a result, many texts on computability theory strike today's computer science students as far removed from their concerns. To remedy this, we base our approach to computability on the language of while-programs, a lean subset of PASCAL, and postpone consideration of such classic models as Turing machines, string-rewriting systems, and p. -recursive functions till the final chapter. Moreover, we balance the presentation of un solvability results such as the unsolvability of the Halting Problem with a presentation of the positive results of modern programming methodology, including the use of proof rules, and the denotational semantics of programs. Computer science seeks to provide a scientific basis for the study of information processing, the solution of problems by algorithms, and the design ...

  7. Special relativity a heuristic approach

    CERN Document Server

    Hassani, Sadri

    2017-01-01

    Special Relativity: A Heuristic Approach provides a qualitative exposition of relativity theory on the basis of the constancy of the speed of light. Using Einstein's signal velocity as the defining idea for the notion of simultaneity and the fact that the speed of light is independent of the motion of its source, chapters delve into a qualitative exposition of the relativity of time and length, discuss the time dilation formula using the standard light clock, explore the Minkowski four-dimensional space-time distance based on how the time dilation formula is derived, and define the components of the two-dimensional space-time velocity, amongst other topics. Provides a heuristic derivation of the Minkowski distance formula Uses relativistic photography to see Lorentz transformation and vector algebra manipulation in action Includes worked examples to elucidate and complement the topic being discussed Written in a very accessible style

  8. Tuberous breast: a new approach.

    Science.gov (United States)

    Ribeiro, L; Canzi, W; Buss, A; Accorsi, A

    1998-01-01

    The authors make a historical summary of the pathologic condition of tuberous breast and describe a new procedure for its correction. The method involves a periareolar approach, dividing the breast in two portions to disrupt the constricting ring, and making an inferiorly based flap or pedicle, as described and used by the senior author since 1969, with publication in 1973. The main goal is to correct the deformity at a one-stage operation, resulting in a periareolar scar only, without the use of alloplastic elements such as prostheses, mesh, or tissue expanders. The authors emphasize that Brazilian patients prefer having small breasts rather than large ones, even though the procedure allows the implantation of pre- or retromuscular implants through the periareolar incision.

  9. Endoscopic approach to subepithelial lesions.

    Science.gov (United States)

    Menon, Laila; Buscaglia, Jonathan M

    2014-05-01

    Endoscopy and endoscopic ultrasound (EUS) play a critical role in the detection and management of subepithelial lesions of the gastrointestinal tract. The most common subepithelial lesions detected by endoscopists are gastrointestinal stromal tumors (GISTs), leiomyomas, lipomas, granular cell tumors (GCTs), pancreatic rests and carcinoid tumors. These lesions can be classified based on unique histochemical staining and the gastrointestinal layer of origin. While the majority of the lesions are considered benign, some tumors such as GISTs and carcinoids have a strong propensity for malignant transformation. Therefore, appropriate endoscopic versus surgical management based on size and location is crucial in the prevention of malignant transformation and metastasis. In this review, we provide a systematic approach to the diagnosis, management and treatment of commonly encountered subepithelial lesions.

  10. Branding approach and valuation models

    Directory of Open Access Journals (Sweden)

    Mamula Tatjana

    2006-01-01

    Full Text Available Much of the skill of marketing and branding nowadays is concerned with building equity for products whose characteristics, pricing, distribution and availability are really quite close to each other. Brands allow the consumer to shop with confidence. The real power of successful brands is that they meet the expectations of those that buy them or, to put it another way, they represent a promise kept. As such they are a contract between a seller and a buyer: if the seller keeps to its side of the bargain, the buyer will be satisfied; if not, the buyer will in future look elsewhere. Understanding consumer perceptions and associations is an important first step to understanding brand preferences and choices. In this paper, we discuss different models to measure value of brand according to couple of well known approaches according to request by companies. We rely upon several empirical examples.

  11. Dietary approaches to prevent hypertension.

    Science.gov (United States)

    Bazzano, Lydia A; Green, Torrance; Harrison, Teresa N; Reynolds, Kristi

    2013-12-01

    Elevated blood pressure arises from a combination of environmental and genetic factors and the interactions of these factors. A substantial body of evidence from animal studies, epidemiologic studies, meta-analyses, and randomized controlled trials has demonstrated that certain dietary patterns and individual dietary elements play a prominent role in the development of hypertension. Changes in diet can lower blood pressure, prevent the development of hypertension, and reduce the risk of hypertension-related complications. Dietary strategies for the prevention of hypertension include reducing sodium intake, limiting alcohol consumption, increasing potassium intake, and adopting an overall dietary pattern such as the DASH (Dietary Approaches to Stop Hypertension) diet or a Mediterranean diet. In order to reduce the burden of blood pressure-related complications, efforts that focus on environmental and individual behavioral changes that encourage and promote healthier food choices are warranted.

  12. Pharmacotherapy of Schizophrenia: Ploypharmacy Approaches

    Directory of Open Access Journals (Sweden)

    Fatemeh Rahiminejad

    2010-07-01

    Full Text Available "nSchizophrenia is a debilitating illness, rating as one of the leading causes of lost years of quality of life. The illness imposes a disproportionate burden on patients and their families, healthcare systems and society. Pharmacological management is the cornerstone of treatment of schizophrenia, and antipsychotics, both first generation of antipsychotics and second generation of antipsychotics, are efficacious in reducing levels of psychopathology in acute episodes of schizophrenia. Clearly a need for innovative treatment strategies in schizophrenia that will ensure increased effectiveness against negative symptoms and cognitive dysfunction dysfunction. Therefore, in majority of cases polypharmacy is one of the effective approaches. This review focused on polypharmacy in the treatment of schizophrenia and in particular negative symptoms.

  13. [Identity and aging: psychosocial approaches].

    Science.gov (United States)

    Danko, Marianna; Arnaud, Christiane; Gély-Nargeot, Marie-Christine

    2009-12-01

    This review is devoted to the notion of identity with regard to the process of aging from various approaches in social sciences. Continuity or transformation of identity is challenged in advanced age according to the place reserved in the society for the elderly subjects and their social age groups. Study methods are discussed in relation with the theoretical models, and their relevance to address aging people singularity and influence of environment. Changes of identity among elderly subjects appear to proceed in two ways. In the first one, called "rebirth", they establish a new self. In the second way, termed "turning point", better strategy for coping the aging effects is obtained by revealing untapped dimensions of the Self.

  14. Laboratory approaches to infectious diarrhea.

    Science.gov (United States)

    Turgeon, D K; Fritsche, T R

    2001-09-01

    Future applications of advanced molecular diagnostics in clinical laboratories will enhance significantly capabilities to diagnose bacterial, parasitic, and viral agents in the early course of disease through enhanced assay sensitivities and specificities and improved turnaround times, theoretically leading to more timely and directed therapeutic intervention. Until such time, clinicians must continue to rely on clinical judgment and the diverse battery of traditional culture techniques, direct examination (including light microscopy and electron microscopy), and immunoassays that are available. Cost considerations and the ever-increasing array of infectious agents responsible for infectious gastroenteritis will continue to drive the development of practice guidelines to assist practitioners with reasoned and reasonable approaches to management of diarrheal illnesses.

  15. Kinetic approach to relativistic dissipation

    Science.gov (United States)

    Gabbana, A.; Mendoza, M.; Succi, S.; Tripiccione, R.

    2017-08-01

    Despite a long record of intense effort, the basic mechanisms by which dissipation emerges from the microscopic dynamics of a relativistic fluid still elude complete understanding. In particular, several details must still be finalized in the pathway from kinetic theory to hydrodynamics mainly in the derivation of the values of the transport coefficients. In this paper, we approach the problem by matching data from lattice-kinetic simulations with analytical predictions. Our numerical results provide neat evidence in favor of the Chapman-Enskog [The Mathematical Theory of Non-Uniform Gases, 3rd ed. (Cambridge University Press, Cambridge, U.K., 1970)] procedure as suggested by recent theoretical analyses along with qualitative hints at the basic reasons why the Chapman-Enskog expansion might be better suited than Grad's method [Commun. Pure Appl. Math. 2, 331 (1949), 10.1002/cpa.3160020403] to capture the emergence of dissipative effects in relativistic fluids.

  16. Approaches to translational plant science

    DEFF Research Database (Denmark)

    Dresbøll, Dorte Bodin; Christensen, Brian; Thorup-Kristensen, Kristian

    2015-01-01

    Translational science deals with the dilemma between basic research and the practical application of scientific results. In translational plant science, focus is on the relationship between agricultural crop production and basic science in various research fields, but primarily in the basic plant...... science. Scientific and technological developments have allowed great progress in our understanding of plant genetics and molecular physiology, with potentials for improving agricultural production. However, this development has led to a separation of the laboratory-based research from the crop production...... is lessened. In our opinion, implementation of translational plant science is a necessity in order to solve the agricultural challenges of producing food and materials in the future. We suggest an approach to translational plant science forcing scientists to think beyond their own area and to consider higher...

  17. Novel therapeutic approaches in chondrosarcoma.

    Science.gov (United States)

    Polychronidou, Genovefa; Karavasilis, Vasilios; Pollack, Seth M; Huang, Paul H; Lee, Alex; Jones, Robin L

    2017-03-01

    Chondrosarcoma is a malignant tumor of bones, characterized by the production of cartilage matrix. Due to lack of effective treatment for advanced disease, the clinical management of chondrosarcomas is exceptionally challenging. Current research focuses on elucidating the molecular events underlying the pathogenesis of this rare bone malignancy, with the goal of developing new molecularly targeted therapies. Signaling pathways suggested to have a role in chondrosarcoma include Hedgehog, Src, PI3k-Akt-mTOR and angiogenesis. Mutations in IDH1/2, present in more than 50% of primary conventional chondrosarcomas, make the development of IDH inhibitors a promising treatment option. The present review discusses the preclinical and early clinical data on novel targeted therapeutic approaches in chondrosarcoma.

  18. Raman spectroscopy an intensity approach

    CERN Document Server

    Guozhen, Wu

    2017-01-01

    This book summarizes the highlights of our work on the bond polarizability approach to the intensity analysis. The topics covered include surface enhanced Raman scattering, Raman excited virtual states and Raman optical activity (ROA). The first chapter briefly introduces the Raman effect in a succinct but clear way. Chapter 2 deals with the normal mode analysis. This is a basic tool for our work. Chapter 3 introduces our proposed algorithm for the Raman intensity analysis. Chapter 4 heavily introduces the physical picture of Raman virtual states. Chapter 5 offers details so that the readers can have a comprehensive idea of Raman virtual states. Chapter 6 demonstrates how this bond polarizability algorithm is extended to ROA intensity analysis. Chapters 7 and 8 offer details on ROA, showing many findings on ROA mechanism that were not known or neglected before. Chapter 9 introduces our proposed classical treatment on ROA which, as combined with the results from the bond polarizability analysis, leads to a com...

  19. How to approach chronic anemia.

    Science.gov (United States)

    Koury, Mark J; Rhodes, Melissa

    2012-01-01

    We present herein an approach to diagnosing the cause of chronic anemia based on a patient's history and complete blood cell count (CBC). Four patterns that are encountered frequently in CBCs associated with chronic anemias are considered: (1) anemia with abnormal platelet and/or leukocyte counts, (2) anemia with increased reticulocyte counts, (3) life-long history of chronic anemia, and (4) anemia with inappropriately low reticulocytes. The pathophysiologic bases for some chronic anemias with low reticulocyte production are reviewed in terms of the bone marrow (BM) events that reduce normal rates of erythropoiesis. These events include: apoptosis of erythroid progenitor and precursor cells by intrinsic and extrinsic factors, development of macrocytosis when erythroblast DNA replication is impaired, and development of microcytosis due to heme-regulated eIF2α kinase inhibition of protein synthesis in iron-deficient or thalassemic erythroblasts.

  20. Mindful approach to University education.

    Science.gov (United States)

    Broggi, Fiorenza; Bomba, Monica; Rimondini, Michela; Mutti, Maura; Pasta, Sara; Ricci, Chiara; Tagliabue, Luca; Valsecchi, Silvia; Monaco, Elide; Neri, Francesca; Oggiano, Silvia; Nacinovich, Renata

    2016-01-01

    A mindful approach to education and training could improve students' reflective capacities and have positive effects on clinical practice because it facilitates a helping relationship. The main aims of this study were to investigate whether participation in a mindful-based University training was associated with increases in mindfulness skills as measured by the 5-Facet M Questionnaire, and to present the Italian validation of the questionnaire. Sixty-seven students from the course Neuro and Psychomotor Therapy were enrolled. They filled in the self-administered 5-Facet M Questionnaire before and 1 month after a mindfulness-based training, focused on role-playing and followed by a feedback group discussion. The Italian version of the 5-Facet M Questionnaire had good psychometric properties. The pre- and post-training analysis showed a significant increase in the subscale 'Observing'. Findings suggest that role-playing and feedback group sessions are valid tools to improve students' mindfulness skills.

  1. Elliptic curves a computational approach

    CERN Document Server

    Schmitt, Susanne; Pethö, Attila

    2003-01-01

    The basics of the theory of elliptic curves should be known to everybody, be he (or she) a mathematician or a computer scientist. Especially everybody concerned with cryptography should know the elements of this theory. The purpose of the present textbook is to give an elementary introduction to elliptic curves. Since this branch of number theory is particularly accessible to computer-assisted calculations, the authors make use of it by approaching the theory under a computational point of view. Specifically, the computer-algebra package SIMATH can be applied on several occasions. However, the book can be read also by those not interested in any computations. Of course, the theory of elliptic curves is very comprehensive and becomes correspondingly sophisticated. That is why the authors made a choice of the topics treated. Topics covered include the determination of torsion groups, computations regarding the Mordell-Weil group, height calculations, S-integral points. The contents is kept as elementary as poss...

  2. Possible State Approaches to Cryptocurrencies

    Directory of Open Access Journals (Sweden)

    Jan Lansky

    2018-01-01

    Full Text Available Cryptocurrencies are a type of digital currencies that are relying on cryptographic proofs for confirmation of transactions. Cryptocurrencies usually achieve a unique combination of three features: ensuring limited anonymity, independence from central authority and double spending attack protection. No other group of currencies, including fiat currencies, has this combination of features. We will define cryptocurrency ownership and account anonymity. We will define cryptocurrency ownership and account anonymity. We will introduce a classification of the types of approaches to regulation of cryptocurrencies by various individual countries. We will present the risks that the use of cryptocurrencies involves and the possibilities of prevention of those risks. We will present the possible use of cryptocurrencies for the benefit of the state. The conclusion addresses the implications of adoption of a cryptocurrency as a national currency.

  3. Queueing networks a fundamental approach

    CERN Document Server

    Dijk, Nico

    2011-01-01

    This handbook aims to highlight fundamental, methodological and computational aspects of networks of queues to provide insights and to unify results that can be applied in a more general manner.  The handbook is organized into five parts: Part 1 considers exact analytical results such as of product form type. Topics include characterization of product forms by physical balance concepts and simple traffic flow equations, classes of service and queue disciplines that allow a product form, a unified description of product forms for discrete time queueing networks, insights for insensitivity, and aggregation and decomposition results that allow subnetworks to be aggregated into single nodes to reduce computational burden. Part 2 looks at monotonicity and comparison results such as for computational simplification by either of two approaches: stochastic monotonicity and ordering results based on the ordering of the proces generators, and comparison results and explicit error bounds based on an underlying Markov r...

  4. Bruxism and Current Treatment Approaches

    Directory of Open Access Journals (Sweden)

    Selin Eren

    2016-06-01

    Full Text Available Among the mastication system disorders bruxism is a parafunctional behavior that comes from psychophysiological origin. Epidemiologic studies have reported great variability of bruxism prevalence. The factors that could cause bruxism is highly controversial. There are different opinions on this issue. The etiologic factors of bruxism include stress, malnutrition, allergic and endocrinologic diseases, central nervous system disorders, genetic factors, medicines, malocclusion, and wrong dental treatment. The aim of treatment of bruxism is to prevent damage that may occur on teeth and in the temporomandibular joint and to eliminate pain. Dental treatment, physical therapy, pharmacological treatment and behavioral and cognitive therapy can be considered for this purpose of treatment. This review summarizes the etiologic factors, epidemiology, diagnosis, and current treatment approaches of patient with bruxism. [Archives Medical Review Journal 2016; 25(2.000: 241-258

  5. Managerial Leadership - A Theoretical Approach

    Directory of Open Access Journals (Sweden)

    Felicia Cornelia MACARIE

    2007-06-01

    Full Text Available The paper endeavors to offer an overview of the major theories on leadership and the way in which it influences the management of contemporary organizations. Numerous scholars highlight that there are numerous overlaps between the concepts of management and leadership. This is the reason why the first section of the paper focuses on providing an extensive overview of the literature regarding the meaning of the two aforementioned concepts. The second section addresses more in depth the concept of leadership and managerial leadership and focuses on the ideal profile of the leader. The last section of the paper critically discusses various types of leadership and more specifically modern approaches to the concept and practices of leadership.

  6. Molecular approaches for bacterial azoreductases

    Directory of Open Access Journals (Sweden)

    Montira Leelakriangsak

    2013-12-01

    Full Text Available Azo dyes are the dominant types of synthetic dyes, widely used in textiles, foods, leather, printing, tattooing, cosmetics, and pharmaceutical industries. Many microorganisms are able to decolorize azo dyes, and there is increasing interest in biological waste treatment methods. Bacterial azoreductases can cleave azo linkages (-N=N- in azo dyes, forming aromatic amines. This review mainly focuses on employing molecular approaches, including gene manipulation and recombinant strains, to study bacterial azoreductases. The construction of the recombinant protein by cloning and the overexpression of azoreductase is described. The mechanisms and function of bacterial azoreductases can be studied by other molecular techniques discussed in this review, such as RT-PCR, southern blot analysis, western blot analysis, zymography, and muta-genesis in order to understand bacterial azoreductase properties, function and application. In addition, understanding the regulation of azoreductase gene expression will lead to the systematic use of gene manipulation in bacterial strains for new strategies in future waste remediation technologies.

  7. Four Approaches to Project Evaluation

    DEFF Research Database (Denmark)

    Laursen, Markus; Svejvig, Per; Rode, Anna Le Gerstrøm

    There are many theoretical and practical reasons for evaluating projects – including explorative arguments focusing on expanding descriptive knowledge on project work as well as normative arguments focusing on improving prescriptive models of project performance. Despite the need for project...... management methodologies that work and combat project failure, and research methods that can assess effective project management and methodologies, as well as empirical research on the actuality of projects as practice, evaluation research on projects including project management and methodologies is scarce....... Each of the framework’s four approaches provides a distinct evaluation that sheds light on some issues while leaving others unattended. Following these lines, the paper calls for more multi-faceted project evaluations. Introducing a framework that can help analyze existing evaluations and structure...

  8. Spinal trauma. An imaging approach

    Energy Technology Data Exchange (ETDEWEB)

    Cassar-Pullicino, V.N. [The Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry, Shropshire (United Kingdom). Dept. of Radiology; Imhof, H. [University and General Hospital Vienna (Austria). Dept. of Radiodiagnostics

    2006-07-01

    The diagnosis of trauma to the spine - where the slightest oversight may have catastrophic results - requires a thorough grasp of the spectrum of resultant pathology as well as the imaging modalities used in making an accurate diagnosis. In Spinal Trauma, the internationally renowned team of experts provides a comprehensive, cutting-edge exposition of the current vital role of imaging in the diagnosis and treatment of injuries to the axial skeleton. Beginning with a valuable clinical perspective of spinal trauma, the book offers the reader a unique overview of the biomechanics underlying the pathology of cervical trauma. Acute trauma topics include: - Optimization of imaging modalities - Malalignment - signs and significance - Vertebral fractures - detection and implications - Classification of thoraco-lumbar fractures - rationale and relevance - Neurovascular injury. Distilling decades of clinical and teaching expertise, the contributors further discuss the current role of imaging in special focus topics, which include: - The pediatric spine - Sports injuries - The rigid spine - Trauma in the elderly - Vertebral collapse, benign and malignant - Spinal trauma therapy - Vertebral fractures and osteoporosis - Neuropathic spine. All throughout the book, the focus is on understanding the injury, and its implications and complications, through 'an imaging approach'. Lavishly illustrated with hundreds of superb MR images and CT scans, and clear full-color drawings, the authors conclude with a look into the future, defining clinical trends and research directions. Spinal Trauma - with its broad scope, practical imaging approach, and current focus - is designed to enhance confidence and accuracy, making it essential reading for clinicians and radiologists at all levels. (orig.)

  9. Design approaches to experimental mediation.

    Science.gov (United States)

    Pirlott, Angela G; MacKinnon, David P

    2016-09-01

    Identifying causal mechanisms has become a cornerstone of experimental social psychology, and editors in top social psychology journals champion the use of mediation methods, particularly innovative ones when possible (e.g. Halberstadt, 2010, Smith, 2012). Commonly, studies in experimental social psychology randomly assign participants to levels of the independent variable and measure the mediating and dependent variables, and the mediator is assumed to causally affect the dependent variable. However, participants are not randomly assigned to levels of the mediating variable(s), i.e., the relationship between the mediating and dependent variables is correlational. Although researchers likely know that correlational studies pose a risk of confounding, this problem seems forgotten when thinking about experimental designs randomly assigning participants to levels of the independent variable and measuring the mediator (i.e., "measurement-of-mediation" designs). Experimentally manipulating the mediator provides an approach to solving these problems, yet these methods contain their own set of challenges (e.g., Bullock, Green, & Ha, 2010). We describe types of experimental manipulations targeting the mediator (manipulations demonstrating a causal effect of the mediator on the dependent variable and manipulations targeting the strength of the causal effect of the mediator) and types of experimental designs (double randomization, concurrent double randomization, and parallel), provide published examples of the designs, and discuss the strengths and challenges of each design. Therefore, the goals of this paper include providing a practical guide to manipulation-of-mediator designs in light of their challenges and encouraging researchers to use more rigorous approaches to mediation because manipulation-of-mediator designs strengthen the ability to infer causality of the mediating variable on the dependent variable.

  10. EFQM approach and the Dutch Quality Award

    NARCIS (Netherlands)

    Nabitz, U. W.; Klazinga, N. S.

    1999-01-01

    Different approaches to improve quality are used in organizations delivering health care. Donabedian introduced structure, process and outcome, from which other approaches like self-assessment, accreditation, visitation, International Standards Organisation (ISO) and European Foundation for Quality

  11. Writing approaches of student teachers of English

    National Research Council Canada - National Science Library

    Karabınar, Selma

    2014-01-01

    .... "The approaches to writing framework" (Biggs, 1988; Lavelle, 1993) presents a different perspective based on the notion that strategies used by the writers are determined by deep or surface level approaches...

  12. Scientific Overview /Regional Analyses and Approaches

    Science.gov (United States)

    A workshop, Tools for Assessing Stream Dissolved Minerals, will introduce approaches and EPA tools for regional and site specific development of water quality criteria based on observations from Arkansas streams. In this presentation regional approaches and tools are described. ...

  13. Multidisciplinary approach for evaluation of neurocutaneous ...

    African Journals Online (AJOL)

    Multidisciplinary approach for evaluation of neurocutaneous disorders in children in Sohag University Hospital, Upper Egypt. ... rhabdomyoma. Conclusion: Neurocutaneous disorders had multiple clinical presentations and required a team work approach including various specialties in their evaluation and management.

  14. A Stochastic Approach to Stereo Vision

    National Research Council Canada - National Science Library

    Barnard, Stephen T

    1986-01-01

    A stochastic optimization approach to stereo matching is presented. Unlike conventional correlation matching and feature matching, the approach provides a dense array of disparities, eliminating the need for interpolation...

  15. A systems approach to traditional oriental medicine

    DEFF Research Database (Denmark)

    Kim, Hyun Uk; Ryu, Jae Yong; Lee, Jong Ok

    2015-01-01

    Analyzing structural similarities between compounds derived from traditional oriental medicine and human metabolites is a systems-based approach that can help identify mechanisms of action and suggest approaches to reduce toxicity.......Analyzing structural similarities between compounds derived from traditional oriental medicine and human metabolites is a systems-based approach that can help identify mechanisms of action and suggest approaches to reduce toxicity....

  16. Systems approach to reduce errors in surgery

    NARCIS (Netherlands)

    Dankelman, J.; Grimbergen, C. A.

    2005-01-01

    Reducing the number of medical errors significantly is the challenge for the coming decade. In medicine and in surgery, in particular, errors are traditionally treated as being committed by individuals. To reduce human errors, two approaches can be used: the person approach and the systems approach.

  17. Nonlinear approaches in engineering applications 2

    CERN Document Server

    Jazar, Reza N

    2013-01-01

    Provides updated principles and applications of the nonlinear approaches in solving engineering and physics problems Demonstrates how nonlinear approaches may open avenues to better, safer, cheaper systems with less energy consumption Has a strong emphasis on the application, physical meaning, and methodologies of nonlinear approaches in different engineering and science problems

  18. Risk communication: a mental models approach

    National Research Council Canada - National Science Library

    Morgan, M. Granger (Millett Granger)

    2002-01-01

    ... information about risks. The procedure uses approaches from risk and decision analysis to identify the most relevant information; it also uses approaches from psychology and communication theory to ensure that its message is understood. This book is written in nontechnical terms, designed to make the approach feasible for anyone willing to try it. It is illustrat...

  19. Anterior approach v. posterior approach - ultrasound-guided shoulder arthrogram injection

    Directory of Open Access Journals (Sweden)

    Merle Neethling-du Toit

    2008-11-01

    Full Text Available Anterior approach ultrasound guided arthrogram injections are a quick reliable way of injecting contrast prior to MRI scan. We did a retrospective study on patients, previously injected and scanned at our clinic, to compare the more manifested posterior approach with the anterior approach. The success rate for successful intra-articular injections for the anterior approach far outweighs the posterior approach. Also the anterior approach is more tolerable for patients as the injections are much quicker and seemingly less painful. In our knowledge it is thus far better to perform anterior approach shoulder arthrogram injections than posterior approach injections

  20. ATR-p53 restricts homologous recombination in response to replicative stress but does not limit DNA interstrand crosslink repair in lung cancer cells.

    Directory of Open Access Journals (Sweden)

    Bianca M Sirbu

    Full Text Available Homologous recombination (HR is required for the restart of collapsed DNA replication forks and error-free repair of DNA double-strand breaks (DSB. However, unscheduled or hyperactive HR may lead to genomic instability and promote cancer development. The cellular factors that restrict HR processes in mammalian cells are only beginning to be elucidated. The tumor suppressor p53 has been implicated in the suppression of HR though it has remained unclear why p53, as the guardian of the genome, would impair an error-free repair process. Here, we show for the first time that p53 downregulates foci formation of the RAD51 recombinase in response to replicative stress in H1299 lung cancer cells in a manner that is independent of its role as a transcription factor. We find that this downregulation of HR is not only completely dependent on the binding site of p53 with replication protein A but also the ATR/ATM serine 15 phosphorylation site. Genetic analysis suggests that ATR but not ATM kinase modulates p53's function in HR. The suppression of HR by p53 can be bypassed under experimental conditions that cause DSB either directly or indirectly, in line with p53's role as a guardian of the genome. As a result, transactivation-inactive p53 does not compromise the resistance of H1299 cells to the interstrand crosslinking agent mitomycin C. Altogether, our data support a model in which p53 plays an anti-recombinogenic role in the ATR-dependent mammalian replication checkpoint but does not impair a cell's ability to use HR for the removal of DSB induced by cytotoxic agents.

  1. Synthesis and Characterization of Poly (styrene-co-butyl acrylate)/Silica Aerogel Nanocomposites by in situ AGET ATRP: Investigating Thermal Properties

    Science.gov (United States)

    Khezri, Khezrollah; Fazli, Yousef

    2017-10-01

    Hydrophilic silica aerogel nanoparticles surface was modified with hexamethyldisilazane. Then, the resultant modified nanoparticles were used in random copolymerization of styrene and butyl acrylate via activators generated by electron transfer for atom transfer radical polymerization. Conversion and molecular weight determinations were performed using gas and size exclusion chromatography respectively. Addition of modified nanoparticles by 3 wt% results in a decrease of conversion from 68 to 46 %. Molecular weight of copolymer chains decreases from 12,500 to 7,500 g.mol-1 by addition of 3 wt% modified nanoparticles; however, PDI values increase from 1.1 to 1.4. Proton nuclear magnetic resonance spectroscopy results indicate that the molar ratio of each monomer in the copolymer chains is approximately similar to the initial selected mole ratio of them. Increasing thermal stability of the nanocomposites is demonstrated by thermal gravimetric analysis. Differential scanning calorimetry also shows a decrease in glass transition temperature by increasing modified silica aerogel nanoparticles.

  2. Enhancing the hydrophilic and antifouling properties of polypropylene nonwoven fabric membranes by the grafting of poly(N-vinyl-2-pyrrolidone) via the ATRP method.

    Science.gov (United States)

    Wang, Chanchan; Feng, Ranran; Yang, Fenglin

    2011-05-15

    In this work, the surface characteristics of poly(N-vinyl-2-pyrrolidone) (PNVP)-modified nonwoven fabric (NWF) membranes and the effects of the surface characteristics on the membranes antifouling properties were investigated. Effects of grafting time, grafting temperature, and monomer concentration on the grafting degree of PNVP were systematically investigated. The effect of grafting degree on the surface characteristics was also investigated. Scanning electron microscopy (SEM) was used to characterize the structural and morphological changes on the membrane surface. The water contact angles decreased from 113±1.2° to 52±3°, which means that the hydrophilicity of the modified NWF was enhanced with increasing PNVP grafting degree. The surface free energy was calculated, which showed an increase after modification. Static bovine serum albumin (BSA) adsorption experiments were carried out, which showed a decrease of 82.5%. Permeation experiments of water and supernatant solution of active sludge were carried out to determine the antifouling characteristics against the extracellular polymeric substance. Results demonstrated that the modified NWF had higher permeation fluxes and lower flux loss in comparison with the original NWF. Bacterial adhesion on the membrane surface was largely suppressed after the introduction of PNVP. Copyright © 2011 Elsevier Inc. All rights reserved.

  3. USE OF AN IMMOBILIZED/SOLUBLE HYBRID ATRP CATALYST SYSTEM FOR THE PREPARATION OF BLOCK COPOLYMERS, RANDOM COPOLYMERS AND POLYMERS WITH HIGH CHAIN END FUNCTIONALITY. (R829580)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  4. Two approaches to physics tutoring

    Science.gov (United States)

    Solomaniuck, Tania

    One in two first-year students at science or biomedical faculties fail in basic subjects such as mathematics, chemistry or physics. Course-specific tutoring is one of the available means for improving their performance. In the present research, two tutoring models are developed. Both incorporate independent learning, but from different perspectives and priorities. A pragmatic tutoring approach. The first part of the thesis describes the search process for an optimal course-specific tutoring strategy for a standard first-year physics course in life sciences curricula. After a number of empirical research rounds, a pragmatic compromise emerged as the most suitable form of tutoring. The approach is characterised by: (1) priority to questions from students; (2) a high degree of interactivity with the tutor and among students; (3) due consideration to the number of questions to be dealt with and the depth in which they should be discussed. Most students participating in the tutoring sessions expressed their satisfaction and performed sufficiently well in their exams. However, there was still a problem: the students' insight into the course material was restricted to first-order processing of the syllabus. While this would be satisfactory in non-scientific study programmes, it is deemed insufficient in programmes where deeper insight is required in order that students be able to deal adequately with new conceptual questions or problems. In-depth tutoring. In science programmes, the core objective is for students to acquire in-depth knowledge. Therefore, science educators are designing and studying teaching methods that are geared not only to the acquisition of in-depth knowledge as such, but also to the motivation of students to take a more in-depth approach to learning. Some of the crucial notions in their research are: the extent to which the course content ties in with students' prior knowledge, problem-setting strategies and concept-context linking. 'In

  5. Molecular approaches in experimental neuroimaging

    Energy Technology Data Exchange (ETDEWEB)

    Tavitian, B. [CEA Saclay, 91 - Gif sur Yvette (France)

    2009-07-01

    We quantified and compared six parameters (resolution, depth, sensitivity, portability, quantification and cost) of four molecular imaging techniques (MRI, optics, ultrasound and TEP), with the three types of electromagnetic radiation used in vivo (Frequencies (10{sup 6} to 10{sup 22} Hz), Photonic Energy (10{sup -4} to 10{sup 9} eV) and Wavelengths (10{sup -2} to 10{sup -15} m)). This form of molecular imaging demands the most sensitive technique available (Pl. 26-2 to 26-4). Four examples of experimental in vivo approaches on small animals are shown: molecular passage through the blood-brain barrier (endothelial cells, astrocytes and occludin, pharmacokinetics, studied with PET) (Pl. 2-5 to 2-11); imaging of receptors and ligands, especially peripheral benzodiazepine receptors (PBR) by PET and MRI in the rat (Pl. 2-12 to Pl. 2-15); neuro-pathology of neuro-degenerative and inflammatory diseases and stroke by PET and MRI in the rat (Pl. 2-16 to 2-17); and the study of responses to stimulation explored with in vivo imaging of calcium signals and their variations by photonic analysis, as on the scale of mitochondrial calcium (Pl.2-18 to Pl.2-22). (author)

  6. Emerging approaches in predictive toxicology.

    Science.gov (United States)

    Zhang, Luoping; McHale, Cliona M; Greene, Nigel; Snyder, Ronald D; Rich, Ivan N; Aardema, Marilyn J; Roy, Shambhu; Pfuhler, Stefan; Venkatactahalam, Sundaresan

    2014-12-01

    Predictive toxicology plays an important role in the assessment of toxicity of chemicals and the drug development process. While there are several well-established in vitro and in vivo assays that are suitable for predictive toxicology, recent advances in high-throughput analytical technologies and model systems are expected to have a major impact on the field of predictive toxicology. This commentary provides an overview of the state of the current science and a brief discussion on future perspectives for the field of predictive toxicology for human toxicity. Computational models for predictive toxicology, needs for further refinement and obstacles to expand computational models to include additional classes of chemical compounds are highlighted. Functional and comparative genomics approaches in predictive toxicology are discussed with an emphasis on successful utilization of recently developed model systems for high-throughput analysis. The advantages of three-dimensional model systems and stem cells and their use in predictive toxicology testing are also described. © 2014 Wiley Periodicals, Inc.

  7. Diagnostic approach to peripheral neuropathy

    Directory of Open Access Journals (Sweden)

    Misra Usha

    2008-01-01

    Full Text Available Peripheral neuropathy refers to disorders of the peripheral nervous system. They have numerous causes and diverse presentations; hence, a systematic and logical approach is needed for cost-effective diagnosis, especially of treatable neuropathies. A detailed history of symptoms, family and occupational history should be obtained. General and systemic examinations provide valuable clues. Neurological examinations investigating sensory, motor and autonomic signs help to define the topography and nature of neuropathy. Large fiber neuropathy manifests with the loss of joint position and vibration sense and sensory ataxia, whereas small fiber neuropathy manifests with the impairment of pain, temperature and autonomic functions. Electrodiagnostic (EDx tests include sensory, motor nerve conduction, F response, H reflex and needle electromyography (EMG. EDx helps in documenting the extent of sensory motor deficits, categorizing demyelinating (prolonged terminal latency, slowing of nerve conduction velocity, dispersion and conduction block and axonal (marginal slowing of nerve conduction and small compound muscle or sensory action potential and dennervation on EMG. Uniform demyelinating features are suggestive of hereditary demyelination, whereas difference between nerves and segments of the same nerve favor acquired demyelination. Finally, neuropathy is classified into mononeuropathy commonly due to entrapment or trauma; mononeuropathy multiplex commonly due to leprosy and vasculitis; and polyneuropathy due to systemic, metabolic or toxic etiology. Laboratory investigations are carried out as indicated and specialized tests such as biochemical, immunological, genetic studies, cerebrospinal fluid (CSF examination and nerve biopsy are carried out in selected patients. Approximately 20% patients with neuropathy remain undiagnosed but the prognosis is not bad in them.

  8. A practical approach to fibromyalgia.

    Science.gov (United States)

    Brecher, L S; Cymet, T C

    2001-04-01

    The term fibromyalgia refers to a collection of symptoms with no clear physiologic cause, but the symptoms together constitute a clearly recognizable and distinct pathologic entity. The diagnosis is made through the examiner's clinical observations. The differential diagnosis must include other somatic syndromes as well as disease entities, including hepatitis, hypothyroidism, diabetes mellitus, electrolyte imbalance, multiple sclerosis, and cancer. Diagnostic criteria serve as guidelines for diagnosis, not as absolute requirements. Treatment of fibromyalgia, which is an ongoing process, remains individualized, relying on a good physician-patient relationship. It is goal-oriented, directed at helping patients get restorative sleep, alleviating the somatic pains, keeping patients productive, and regulating schedules. It can be achieved through a goal-oriented agreement between patient and provider. Because fibromyalgia is chronic and may affect all areas of an individual's functioning, the physician needs to also evaluate the social support systems of patients with fibromyalgia. The approach to treatment should integrate patient education as well as non-pharmacologic and pharmacologic modalities. To keep patients well educated and involved in their healthcare, physicians should provide patients with adequate sources for reliable information.

  9. Comprehensive approach to diabetic nephropathy

    Directory of Open Access Journals (Sweden)

    Bancha Satirapoj

    2014-09-01

    Full Text Available Diabetic nephropathy (DN is a leading cause of mortality and morbidity in patients with diabetes. This complication reflects a complex pathophysiology, whereby various genetic and environmental factors determine susceptibility and progression to end-stage renal disease. DN should be considered in patients with type 1 diabetes for at least 10 years who have microalbuminuria and diabetic retinopathy, as well as in patients with type 1 or type 2 diabetes with macroalbuminuria in whom other causes for proteinuria are absent. DN may also present as a falling estimated glomerular filtration rate with albuminuria as a minor presenting feature, especially in patients taking renin–angiotensin–aldosterone system inhibitors (RAASi. The pathological characteristic features of disease are three major lesions: diffuse mesangial expansion, diffuse thickened glomerular basement membrane, and hyalinosis of arterioles. Functionally, however, the pathophysiology is reflected in dysfunction of the mesangium, the glomerular capillary wall, the tubulointerstitium, and the vasculature. For all diabetic patients, a comprehensive approach to management including glycemic and hypertensive control with RAASi combined with lipid control, dietary salt restriction, lowering of protein intake, increased physical activity, weight reduction, and smoking cessation can reduce the rate of progression of nephropathy and minimize the risk for cardiovascular events. This review focuses on the latest published data dealing with the mechanisms, diagnosis, and current treatment of DN.

  10. Ancient Climatic Architectural Design Approach

    Directory of Open Access Journals (Sweden)

    Nasibeh Faghih

    2013-01-01

    Full Text Available Ancient climatic architecture had found out a series of appropriate responses for the best compatibility with the critical climate condition for instance, designing ‘earth sheltered houses’ and ‘courtyard houses’. They could provide human climatic comfort without excessive usage of fossil fuel resources. Owing to the normal thermal conditions in the ground depth, earth sheltered houses can be slightly affected by thermal fluctuations due to being within the earth. In depth further than 6.1 meters, temperature alternation is minute during the year, equaling to average annual temperature of outside. More to the point, courtyard buildings as another traditional design approach, have prepared controlled climatic space based on creating the maximum shade in the summer and maximum solar heat absorption in the winter. The courtyard houses served the multiple functions of lighting to the rooms, acting as a heat absorber in the summer and a radiator in the winter, as well as providing an open space inside for community activities. It must be noted that they divided into summer and winter zones located in south and north of the central courtyard where residents were replaced into them according to changing the seasons. Therefore, Ancient climatic buildings provided better human thermal comfort in comparison with the use contemporary buildings of recent years, except with the air conditioning

  11. Newer approaches to malaria control.

    Science.gov (United States)

    Damodaran, Se; Pradhan, Prita; Pradhan, Suresh Chandra

    2011-07-01

    Malaria is the third leading cause of death due to infectious diseases affecting around 243 million people, causing 863,000 deaths each year, and is a major public health problem. Most of the malarial deaths occur in children below 5 years and is a major contributor of under-five mortality. As a result of environmental and climatic changes, there is a change in vector population and distribution, leading to resurgence of malaria at numerous foci. Resistance to antimalarials is a major challenge to malaria control and there are new drug developments, new approaches to treatment strategies, combination therapy to overcome resistance and progress in vaccine development. Now, artemisinin-based combination therapy is the first-line therapy as the malarial parasite has developed resistance to other antimalarials. Reports of artemisinin resistance are appearing and identification of new drug targets gains utmost importance. As there is a shift from malaria control to malaria eradication, more research is focused on malaria vaccine development. A malaria vaccine, RTS,S, is in phase III of development and may become the first successful one. Due to resistance to insecticides and lack of environmental sanitation, the conventional methods of vector control are turning out to be futile. To overcome this, novel strategies like sterile insect technique and transgenic mosquitoes are pursued for effective vector control. As a result of the global organizations stepping up their efforts with continued research, eradication of malaria can turn out to be a reality.

  12. Buried penis: classification surgical approach.

    Science.gov (United States)

    Hadidi, Ahmed T

    2014-02-01

    The purpose of this study was to describe morphological classification of congenital buried penis (BP) and present a versatile surgical approach for correction. Sixty-one patients referred with BP were classified into 3 grades according to morphological findings: Grade 1-29 patients with Longer Inner Prepuce (LIP) only, Grade II-20 patients who presented with LIP associated with indrawn penis that required division of the fundiform and suspensory ligaments, and Grade III-12 patients who had in addition to the above, excess supra-pubic fat. A ventral midline penile incision extending from the tip of prepuce down to the penoscrotal junction was used in all patients. The operation was tailored according to the BP Grade. All patients underwent circumcision. Mean follow up was 3 years (range 1 to 10). All 61 patients had an abnormally long inner prepuce (LIP). Forty-seven patients had a short penile shaft. Early improvement was noted in all cases. Satisfactory results were achieved in all 29 patients in grade I and in 27 patients in grades II and III. Five children (Grades II and III) required further surgery (9%). Congenital buried penis is a spectrum characterized by LIP and may include in addition; short penile shaft, abnormal attachment of fundiform, and suspensory ligaments and excess supra-pubic fat. Congenital Mega Prepuce (CMP) is a variant of Grade I BP, with LIP characterized by intermittent ballooning of the genital area. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. INFORMATIONAL APPROACH ON TRAINING PROCESS

    Directory of Open Access Journals (Sweden)

    Šemsudin Plojović

    2006-06-01

    Full Text Available Information technology is very important part in training process. Training process is always in innovation and assembling faze, especially at those that want to compete on international level. In that surrounding training process, as the trainers also, must be transformed. Great deal of information must be reliable for headquarter for optimal training process. Informational approach on training process, subject of this research, represent informational technologies and information systems with all aspects an possibilities of applications in sport. Information technology, information system and its application in sport in last decade is developed very fast in last decade. Computer is used, not only for data process, but also for making decisions. That is the key moment changing the basics of information system, especially the role of information system in training process. To define key words connected for information systems in sport we will start from characteristics of information, exchanging in this relations: man to man, machine to machine, man to machine, and opposite, machine to man. According to this we need to make the difference between data and information. In this research we talk about concrete application of information technology and information system as the backup of training process. Behind practical application of IT in sport, that is the main issue of this work, stands the marvelous results of athletes from AK Novi Pazar. Azra Eminovic, Edin Zukovic, Muamer Hasanovic, Emir Koca and Senadin Plojovic, they’ve achieved great results with information back up of training process.

  14. Common approach to common interests

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-06-01

    In referring to issues confronting the energy field in this region and options to be exercised in the future, I would like to mention the fundamental condition of the utmost importance. That can be summed up as follows: any subject in energy area can never be solved by one country alone, given the geographical and geopolitical characteristics intrinsically possessed by energy. So, a regional approach is needed and it is especially necessary for the main players in the region to jointly address problems common to them. Though it may be a matter to be pursued in the distant future, I am personally dreaming a 'Common Energy Market for Northeast Asia,' in which member countries' interests are adjusted so that the market can be integrated and the region can become a most economically efficient market, thus formulating an effective power to encounter the outside. It should be noted that Europe needed forty years to integrate its market as the unified common market. It is necessary for us to follow a number of steps over the period to eventually materialize our common market concept, too. Now is the time for us to take a first step to lay the foundation for our descendants to enjoy prosperity from such a common market.

  15. [Clinical approach to imported eosinophilia].

    Science.gov (United States)

    Cañas García-Otero, Elías; Praena-Segovia, Julia; Ruiz-Pérez de Pipaón, Maite; Bosh-Guerra, Xerach; Sánchez-Agüera, Magdalena; Álvarez-Martínez, Daniel; Cisneros-Herreros, José Miguel

    2016-12-01

    Eosinophilia is a common finding in international travelers and immigrants, being an helmintic infection its main etiology. The positive predictive value of eosinophilia for an helmintosis is low in travellers. Eosinophilia may be an incidental finding, or symptomatic, and it represents a clinical challenge due to the low sensitivity and specificity of direct and indirect parasitological diagnostic tests, respectively. It requires a structured approach based on geographical areas, environmental exposures and behavioral risks, and associated symptoms. The initial assessment should include a comprehensive and tailored anamnesis and physical examination, basic laboratory tests, a complete parasitological examination of stool samples and a Strongyloides stercoralis serology, supplemented with other explorations guided by epidemiological and clinical suspicion. Empiric treatment with albendazole and/or ivermectin (plus praziquantel if risk of schistosomiasis) is an option for unidentified persistent eosinophilia after study, and in persons in whom a proper assessment or follow-up can not be assured. In patients at risk for estrongiloidosis who are candidates for immunosuppressive therapies, it is indicated a prior screening and treatment to prevent a future hyperinfestation syndrome. Copyright © 2016 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

  16. Current Approach to Child Rights

    Directory of Open Access Journals (Sweden)

    Huseyin Dag

    2015-03-01

    Full Text Available Rights of children, legally or morally all over the world that children are born with; education, health, life, shelter; physical, psychological or sexual exploitation protection of such rights is universal concept used to describethemall. Rights of children is an issue that should be addressed in the concept of human rights. Today, there are many parts of the world that human rights violations, child-size and grew broader, more difficult to intervene in a way that is situated. The idea that children than in adults of different physical, physiological, behavioral and psychological characteristics that continuous growth and improve dawareness that the establishment of thecare of children a society where the problem is and scientific approach everyone with this responsibility should be installed is shaped in Geneva Declaration of Childrens Rights. Today, the international document related to childrens rights is the United Nations Convention on the Rights of the Child adoptedand approved by 193 countries. Child policy in Turkey where 25 million children live is an issue that should be seriously considered. Thus, childrens rights, children working in coordination with the contract on the basis of a policy should be implemented fully. [Cukurova Med J 2015; 40(1.000: 1-5

  17. Biomimetic approach to dental implants.

    Science.gov (United States)

    Kim, Tae-Il; Jang, Jun-Hyeog; Kim, Hae-Won; Knowles, Jonathan C; Ku, Young

    2008-01-01

    Titanium, as an implant material, is regarded to be durable and biocompatible, which allows functional replacement of missing teeth. Successful dental implantation depends on an osseointegration phenomenon, a direct structural and functional binding reaction between bone and implant. It is well known that physicochemical characteristics of the dental implant surface, such as roughness, topography, chemistry, and electrical charge affect the biological reactions occurring at the interface of tissue and implant. Therefore, considerable efforts have been made to modify the surface of titanium implants which are based on mechanical, physical and chemical treatments. Recently, biological molecules were introduced onto the surface of implants to stimulate osteogenic cells in the early stage of implantation and consequently accelerate bone formation around implant and subsequent rapid implant stabilization. A range of extracellular matrix components, designed peptides, and growth factors have been proposed as the biological moiety. In this review, we address several issues related to the biology of dental implants and discuss biomimetic modification of the implant surface as a novel approach to obtain successful osseointegration.

  18. Nonstationary Approaches to Hydrologic Design

    Science.gov (United States)

    Vogel, Richard; Hecht, Jory; Read, Laura

    2014-05-01

    We introduce a generalized framework for evaluating the risk, reliability and return period of hydrologic events in a nonstationary world. A heteroscedastic regression model is introduced as an elegant and general framework for modeling trends in the mean and/or variance of hydrologic records using ordinary least squares regression methods. A regression approach to modeling trends has numerous advantages over other methods including: (1) ease of application, (2) considers linear or nonlinear trends, (3) graphical display of trends, (4) analytical estimate of the power of the trend test and prediction intervals associated with trend extrapolation. Traditional statements of risk, reliability and return periods which assume that the annual probability of a flood event remains constant throughout the project horizon are revised to include the impacts of trends in the mean and/or variance of hydrologic records. Our analyses reveal that in a nonstationary world, meaningful expressions of the likelihood of future hydrologic events are unlikely to result from knowledge of return periods whereas knowledge of system reliability over future planning horizons can effectively communicate the likelihood of future hydrologic events of interest.

  19. The wonder approach to learning

    Directory of Open Access Journals (Sweden)

    Catherine eL'Ecuyer

    2014-10-01

    Full Text Available Wonder, innate in the child, is an inner desire to learn that awaits reality in order to be awakened. Wonder is at the origin of reality-based consciousness, thus of learning. The scope of wonder, which occurs at a metaphysical level, is greater than that of curiosity. Unfortunate misinterpretations of neuroscience have led to false brain-based ideas in the field of education, all of these based on the scientifically wrong assumption that children’s learning depends on an enriched environment. These beliefs have re-enforced the Behaviorist Approach to education and to parenting and have contributed to deadening our children’s sense of wonder. We suggest wonder as the center of all motivation and action in the child. Wonder is what makes life genuinely personal. Beauty is what triggers wonder. Wonder attunes to beauty through sensitivity and is unfolded by attachment. When wonder, beauty, sensitivity and secure attachment are present, learning is meaningful.On the contrary, when there is no volitional dimension involved (no wonder, no end or meaning (no beauty and no trusting predisposition (secure attachment, the rigid and limiting mechanical process of so-called learning through mere repetition become a deadening and alienating routine. This could be described as training, not as learning, because it does not contemplate the human being as a whole.

  20. New approaches to nuclear power

    KAUST Repository

    Dewan, Leslie

    2018-01-21

    The world needs a cheap, carbon-free alternative to fossil fuels to feed its growing electricity demand. Nuclear power can be a good solution to the problem, but is hindered by issues of safety, waste, proliferation, and cost. But what if we could try a new approach to nuclear power, one that solves these problems? In this lecture, the CEO of Transatomic Power will talk about how their company is advancing the design of a compact molten salt reactor to support the future of carbon-free energy production. Can the designs of new reactor push the boundaries of nuclear technology to allow for a safe, clean, and affordable answer to humanityメs energy needs? Nuclear power involves capturing the energy produced in nuclear fission reactions, which emerges as heat. This heat is most frequently used to boil water into steam, which then drives a turbine to produce electricity in a nuclear power plant. Worldwide, there is a renaissance of new nuclear technology development -- a new generation of young engineers are racing to develop more advanced nuclear reactors for a better form of power generation. Transatomic Power, specifically, is advancing the design of an easily contained and controlled, atmospheric pressure, high power density molten salt reactor that can be built at low cost. The road to commercialization is long, and poses many challenges, but the benefits are enormous. These new reactors push the boundaries of technology to allow for better, safer ways to power the world.

  1. Understanding Progress: A Heterodox Approach

    Directory of Open Access Journals (Sweden)

    Blanca Lemus

    2013-01-01

    Full Text Available This paper examines the possibility of understanding and measuring well-being as a result of “progress” on the basis of today’s dominant epistemological framework. Market criteria distort social values by allowing purchasing power to define priorities, likening luxury goods to basic needs; in the process they reinforce patterns of discrimination against disadvantaged social groups and women, introducing fatal distortions into the analysis. Similarly, because there are no appropriate mechanisms to price natural resources adequately, the market overlooks the consequences of the abuse of natural resources, degrading the quality of life, individually and collectively, or—in the framework of Latin American indigenous groups—foreclosing the possibility of “living well”. We critique the common vision of the official development discourse that places its faith on technological innovations to resolve these problems. The analysis points to the need for new models of social and environmental governance to promote progress, approaches like those suggested in the paper that are inconsistent with public policies currently in place. At present, the social groups forging institutions to assure their own well-being and ecological balance are involved in local processes, often in opposition to the proposals of the political leaders in their countries.

  2. Approaches towards endogenous pancreatic regeneration.

    Science.gov (United States)

    Banerjee, Meenal; Kanitkar, Meghana; Bhonde, Ramesh R

    2005-01-01

    The phenomenon of pancreatic regeneration in mammals has been well documented. It has been shown that pancreatic tissue is able to regenerate in several species of mammal after surgical insult. This tissue is also known to have the potential to maintain or increase its beta-cell mass in response to metabolic demands during pregnancy and obesity. Since deficiency in beta-cell mass is the hallmark of most forms of diabetes, it is worthwhile understanding pancreatic regeneration in the context of this disease. With this view in mind, this article aims to discuss the potential use in clinical strategies of knowledge that we obtained from studies carried out in animal models of diabetes. Approaches to achieve this goal involve the use of biomolecules, adult stem cells and gene therapy. Various molecules, such as glucagon-like peptide-1, beta-cellulin, nicotinamide, gastrin, epidermal growth factor-1 and thyroid hormone, play major roles in the initiation of endogenous islet regeneration in diabetes. The most accepted hypothesis is that these molecules stimulate islet precursor cells to undergo neogenesis or to induce replication of existing beta-cells, emphasizing the importance of pancreas-resident stem/progenitor cells in islet regeneration. Moreover, the potential of adult stem cell population from bone marrow, umbilical cord blood, liver, spleen, or amniotic membrane, is also discussed with regard to their potential to induce pancreatic regeneration.

  3. Immunological approaches to fertility regulation.

    Science.gov (United States)

    Stevens, V C

    1978-01-01

    Strong evidence that specific immunogenic components of the reproductive system exist that are not represented in other body systems has led to efforts to develop an acceptable vaccine for fertility regulation. The aim is to create a vaccine administered infrequently by trained technicians outside the clinical environment. For safety and practical reasons, an approach using active immunization with a vaccine is preferred to passive immunization with antibodies. In current research with sperm antigens, a lactate dehydrogenase isoenzyme (LDH-X), an enzyme normally present on the sperm surface, reduced fertility in mice and rabbits. However, significant embryo mortality occurred. Other sperm antigens have been tested and rejected. Most of the research on ovum antigens is directed toward the zona pellucida, and work is in progress to isolate experimental quantities of specific zona pellucida antigens. Antibodies to human zona are reported to react with pig zona and vice versa, providing a model system. Antibodies to whole-placenta homogenates reportedly disrupt pregnancy in several laboratory animal species, and 2 placenta-specific proteins are potential antigens since antibodies to them do not react with any other tissue so far tested. Of 3 protein hormones isolated from placental tissue, 2 are potential antigens. The possible hazards of antifertility vaccines can be divided into 2 categories: problems related to immunization and problems caused by antibodies produced.

  4. Approaches to teaching primary level mathematics

    Directory of Open Access Journals (Sweden)

    Caroline Long

    2014-12-01

    Full Text Available In this article we explore approaches to curriculum in the primary school in order to map and manage the omissions implicit in the current unfolding of the Curriculum and Assessment Policy Statement for mathematics. The focus of school-based research has been on curriculum coverage and cognitive depth. To address the challenges of teaching mathematics from the perspective of the learner, we ask whether the learners engage with the subject in such a way that they build foundations for more advanced mathematics. We firstly discuss three approaches that inform the teaching of mathematics in the primary school and which may be taken singly or in conjunction into organising the curriculum: the topics approach, the process approach, and the conceptual fields approach. Each of the approaches is described and evaluated by presenting both their advantages and disadvantages. We then expand on the conceptual fields approach by means of an illustrative example. The planning of an instructional design integrates both a topics and a process approach into a conceptual fields approach. To address conceptual depth within this approach, we draw on five dimensions required for understanding a mathematical concept. In conclusion, we reflect on an approach to curriculum development that draws on the integrated theory of conceptual fields to support teachers and learners in the quest for improved teaching and learning.

  5. Operationalizing the integrated landscape approach in practice

    Directory of Open Access Journals (Sweden)

    Olivia E. Freeman

    2015-03-01

    the process of taking a landscape approach. Drawing on a review of the literature, we identify and discuss three different kinds of landscape approaches: using the landscape scale, a sectoral landscape approach, and an integrated landscape approach. Focusing on an integrated landscape approach, we examine five concepts to help characterize landscape approaches: multifunctionality, transdisciplinarity, participation, complexity, and sustainability. For each term, a continuum of application exists. To help improve and move the integrated landscape approach more toward operationalization, more focus needs to be placed on the process of taking the approach. Although the process can be implemented in a range of ways, in a more integrated approach it will require explicitly defined objectives as well as a clear understanding of what is meant by multifunctionality and sustainability. It will also require collaborative participation, transdisciplinarity/cross-sectoral approaches, managing for adaptive capacity, and applying an iterative process to address the inherent complexity within the system. Although these concepts are not new, we present continuums on which they can exist, allowing for clarification and distinctions to be made regarding what it means to take a landscape approach.

  6. Logical and epistemological approach to critical thinking

    Directory of Open Access Journals (Sweden)

    Pešić Jelena

    2007-01-01

    Full Text Available Two main approaches in the conceptualization of critical thinking, logical and epistemological, are presented and analyzed in this paper. The review of logical approach begins with defining its general framework (relationship between critical thinking and informal logic and afterwards we analyze abilities and skills which are seen as basic constituents of critical thinking. In the review of epistemological approach we analyze four conceptions that present the main directions in criticizing logical approach, and also in developing the broader perspective on critical thinking that includes specific view of knowledge and its development, noncognitive dispositions and the role of subject based knowledge. At the end, we discuss the relationship between logical and epistemological approach. We claim and justify that they should be understood as complementary approaches, and we consider specific contribution of each approach to comprehensive definition of critical thinking. .

  7. Standard Approaches to the Acetabulum Part 1: Kocher-Langenbeck Approach.

    Science.gov (United States)

    Gänsslen, A; Grechenig, S; Nerlich, M; Müller, M

    2016-01-01

    Historically, standard approaches for surgical treatment of displaced acetabular fractures were the KocherLangenbeck approach, the ilioinguinal approach and the extended iliofemoral approach (12). Presently, several modifications of these approaches are accepted alternatives, especially anterior modifications based on the intrapelvic approach described by Hirvensalo (8). Single access approaches allowing visualization of one acetabular column are the posterior Kocher-Langenbeck approach and the anterior ilioinguinal approach (12) and the use of a single approach is favoured (9, 24). For more complex situations, in the 80s and 90s extended approaches (extended iliofemoral approach according to Letournel (12), its modification to Reinert (19) (Baltimore approach), and the Triradiate approach according to Mears (14)) were introduced. These approaches are presently rarely choosen due to the extensive soft tissue dissection and higher complication rates (28). Alternatively, the combination of an anterior and posterior standard approach was recommended (7, 21, 22) having the disadvantage of longer operating time and blood loss and showed no superior results compared to a single approach. The meta-analysis by Giannoudis et al. stated that 48,7% of patients were treated using the Kocher-Langenbeck approach, followed by 21,9% ilioinguinal approaches and 12,4% extended approaches (6). More recent data from the years 2005-2007, showed that anterior approaches are now predominantly used according to a higher number of acetabular fractures with anterior column involvement. Overall, more than 40% of all patients with acetabular fractures are still approached via the Kocher-Langenbeck approach (18). Therefore, the Kocher-Langenbeck approach is still a "working horse" in approaching displaced acetabular fractures. The Kocher-Langenbeck approach consists of two parts. In 1874 von Langenbeck described a longitudinal incision starting from above the greater sciatic notch to the

  8. Approaches to adolescent pregnancy prevention.

    Science.gov (United States)

    Haffner, D; Casey, S

    1986-09-01

    The US has one of the highest teenage pregnancy rates in the industrialized world, over 1,000,000 a year. This can add to social problems including poverty, unemployment, family breakup, juvenile crime, school dropouts, and child abuse. In several studies various approaches have been developed and it is concluded that teens must not only be given the knowledge to avoid teen pregnancies, but the motivation to do so. Sex education is an important part of pregnancy prevention, but few programs go beyond the facts of reproduction and less than 14% of them are 40 hours long. Studies have shown mixed results as to the effect of education on teen pregnancy. There are many programs that have been developed by different communities, including computer programs and youth service agencies. Religious groups also play an important part in sex education and they have some distinct advantages in affecting teens' sexual values and activities. Education programs for teen's parents appear to be very important since studies show when sexuality is discussed at home, the teens begin activity later and use birth control more. Clinics have had difficulty recruiting and retaining teen patients and devote special attention to establishing a rapport with them. The school-based clinic is becoming increasingly popular and can provide birth control counseling, contraceptives, family planning clinic referral, examinations, pregnancy testing, and prenatal care. There success is due to confidentiality, convenience, and comprehensive service. However, since nearly all efforts on teen pregnancy prevention are directed at girls, 1/2 of those involved in teen pregnancies--males--are not participating in programs. This must change for longterm success of these programs and also the involvement of the community and media.

  9. Systemic Approach to Architectural Performance

    Directory of Open Access Journals (Sweden)

    Marie Davidova

    2017-04-01

    Full Text Available First-hand experiences in several design projects that were based on media richness and collaboration are described in this article. Although complex design processes are merely considered as socio-technical systems, they are deeply involved with natural systems. My collaborative research in the field of performance-oriented design combines digital and physical conceptual sketches, simulations and prototyping. GIGA-mapping - is applied to organise the data. The design process uses the most suitable tools, for the subtasks at hand, and the use of media is mixed according to particular requirements. These tools include digital and physical GIGA-mapping, parametric computer aided design (CAD, digital simulation of analyses, as well as sampling and 1:1 prototyping. Also discussed in this article are the methodologies used in several design projects to strategize these tools and the developments and trends in the tools employed.  The paper argues that the digital tools tend to produce similar results through given pre-sets that often do not correspond to real needs. Thus, there is a significant need for mixed methods including prototyping in the creative design process. Media mixing and cooperation across disciplines is unavoidable in the holistic approach to contemporary design. This includes the consideration of diverse biotic and abiotic agents. I argue that physical and digital GIGA-mapping is a crucial tool to use in coping with this complexity. Furthermore, I propose the integration of physical and digital outputs in one GIGA-map and the participation and co-design of biotic and abiotic agents into one rich design research space, which is resulting in an ever-evolving research-design process-result time-based design.

  10. Schwinger's Approach to Einstein's Gravity

    Science.gov (United States)

    Milton, Kim

    2012-05-01

    Albert Einstein was one of Julian Schwinger's heroes, and Schwinger was greatly honored when he received the first Einstein Prize (together with Kurt Godel) for his work on quantum electrodynamics. Schwinger contributed greatly to the development of a quantum version of gravitational theory, and his work led directly to the important work of (his students) Arnowitt, Deser, and DeWitt on the subject. Later in the 1960's and 1970's Schwinger developed a new formulation of quantum field theory, which he dubbed Source Theory, in an attempt to get closer contact to phenomena. In this formulation, he revisited gravity, and in books and papers showed how Einstein's theory of General Relativity emerged naturally from one physical assumption: that the carrier of the gravitational force is a massless, helicity-2 particle, the graviton. (There has been a minor dispute whether gravitational theory can be considered as the massless limit of a massive spin-2 theory; Schwinger believed that was the case, while Van Dam and Veltman concluded the opposite.) In the process, he showed how all of the tests of General Relativity could be explained simply, without using the full machinery of the theory and without the extraneous concept of curved space, including such effects as geodetic precession and the Lense-Thirring effect. (These effects have now been verified by the Gravity Probe B experiment.) This did not mean that he did not accept Einstein's equations, and in his book and full article on the subject, he showed how those emerge essentially uniquely from the assumption of the graviton. So to speak of Schwinger versus Einstein is misleading, although it is true that Schwinger saw no necessity to talk of curved spacetime. In this talk I will lay out Schwinger's approach, and the connection to Einstein's theory.

  11. Fouling-resistant polymer brush coatings

    KAUST Repository

    Thérien-Aubin, Héloïse

    2011-11-01

    A major problem to be addressed with thin composite films used in processes such as coatings or water purification is the biofouling of the surface. To address this problem in a model system, functionalized polyaramide membranes containing an atom transfer radical polymerization (ATRP) initiator were synthesized as a versatile approach to easily modify the surface properties of the polyaramide. Poly(methacrylic acid) brushes were grown using surface initiated ATRP followed by the functionalization of the poly(methacrylic acid) brushes with different side-chains chosen to reduce adhesion between the membrane and foulant. The relation between membrane fouling and the physicochemical properties of the surface was investigated in detail. © 2011 Elsevier Ltd. All rights reserved.

  12. An intelligent approach to nanotechnology

    Science.gov (United States)

    Demming, Anna

    2013-11-01

    Control counts for little without a guiding principle. Whether manipulating atoms with a scanning probe or controlling carrier concentration in thin film deposition, intelligent intervention is required to steer the process from aimless precision towards a finely optimized design. In this issue G M Sacha and P Varona describe how artificial intelligence approaches can help towards modelling and simulating nanosystems, increasing our grasp of the nuances of these systems and how to optimize them for specific applications [1]. More than a labour-saving technique their review also suggests how genetic algorithms and artificial neural networks can supersede existing capabilities to tackle some of the challenges in moving a range of nanotechnologies forward. Research has made giant strides in determining not just what system parameters enhance performance but how. Nanoparticle synthesis is a typical example, where the field has shifted from simple synthesis and observation to unearthing insights as to dominating factors that can be identified and enlisted to control the morphological and chemical properties of synthesized products. One example is the neat study on reaction media viscosity for silver nanocrystal synthesis, where Park, Im and Park in Korea demonstrated a level of size control that had previously proved hard to achieve [2]. Silver nanoparticles have many potential applications including catalysis [3], sensing [4] and surface enhanced Raman scattering [5]. In their study, Park and colleagues obtain size-controlled 30 nm silver nanocrystals in a viscosity controlled medium of 1,5-pentanediol and demonstrate their use as sacrificial cores for the fabrication of a low-refractive filler. Another nanomaterial that has barely seen an ebb in research activity over the past two decades is ZnO, with a legion of reports detailing how to produce ZnO in different nanoscale forms from rods [6], belts [7] and flowers [8] to highly ordered arrays of vertically aligned

  13. [Official approach to sexual abuse].

    Science.gov (United States)

    Oberloskamp, H

    1996-10-01

    , psychotherapeutic treatment instead of, or combined with penal sentence sanctions) and correct inadequate acts (competence of Family Court and Guardianship Court, counterproductive data protection). In conclusion, it must be said that many details concerning the official approach to sexual abuse could be improved. However, the main problem lies in the fact that the State does not really attempt to create a systematic solution to sexual abuse. The ad hoc reaction in Germany has led to an uncoordinated set of rules and practices without a common sense of purpose.

  14. A Tandem Learning Approach to Task Evaluation

    OpenAIRE

    Stewart, Timothy; スチュワート, ティモシー

    2008-01-01

    This paper describes an approach to task evaluation that emerged out of the process of course development. The multi-layered approach to task evaluation described synthesizes student and teacher evaluations of tasks written in journals with more traditional course evaluation data in a reflective process of course development. Ultimately, the approach opens up dynamic insights into the appropriateness of tasks by incorporating the views of both students and teachers.The paper concludes by illu...

  15. A NEW APPROACH TO VIRTUAL EDUCATION

    Directory of Open Access Journals (Sweden)

    Vladimir V. Kureychik

    2014-01-01

    Full Text Available The article discusses several approaches to training, namely the virtual. Concrete examples of virtual learning systems were described, we disclosed their features, advantages and disadvantages. A new suggested approach integrates the features of existing systems, and opens new horizons and opportunities to obtain certain skills and abilities. Introduction of a new approach to the educational process will improve the quality and effectiveness of learning. 

  16. Solution Focused Approach and Usage of Nursing

    OpenAIRE

    Nurcan AKGÜL GÜNDOÐDU; Handan ZÝNCÝR; Nuran GÜLER

    2016-01-01

    "Problem talk creates problems; solution talk creates solutions " Steve de Shazer In recent years, concern for solution-oriented approach has increased in nursing practice. In this review it is aimed to give information about nursing application of solution-oriented approach whose efficacy has been proved with many studies. In addition, solution-oriented approach is what how it turned out, the answer to the question of principle, and that is what the management strategy and what the n...

  17. An approximate analytical approach to resampling averages

    DEFF Research Database (Denmark)

    Malzahn, Dorthe; Opper, M.

    2004-01-01

    Using a novel reformulation, we develop a framework to compute approximate resampling data averages analytically. The method avoids multiple retraining of statistical models on the samples. Our approach uses a combination of the replica "trick" of statistical physics and the TAP approach...... for approximate Bayesian inference. We demonstrate our approach on regression with Gaussian processes. A comparison with averages obtained by Monte-Carlo sampling shows that our method achieves good accuracy....

  18. [Therapeutic approaches in court-ordered therapy].

    Science.gov (United States)

    Floris, Emmanuelle; De Jésus, Arnaud; Cano, Jean-Philippe; Raymondaud, Séverine; Rouveyrol, Éric; Bouchard, Jean-Pierre

    As is the case with other contexts of mental health treatments, the therapeutic approaches to court-ordered therapy are varied. They are based on the principle of their clinical indication and must be delivered by therapists trained in the specific area. The classic therapeutic approaches are used: medication, psychoanalysis and psychoanalytically inspired therapies, cognitive behavioural therapies, group therapies and body-oriented approach. Copyright © 2017. Published by Elsevier Masson SAS.

  19. CULTURAL APPROACHES IN CYBERPORN CRIME PREVENTION

    OpenAIRE

    Prima Angkupi

    2017-01-01

    Limitations of law in cyberporn law enforcement demands the need for non-penal approach as pre-ventive effort to eliminate causes of Cyberporn crimes. This approach includes crime prevention which aims to prevent a crime from being recurred. This approach can be implemented through situ-ational control by active involvement of cultural roles in community. However, it cannot be separat-ed from observing human life variations including childhood, youth, family, school, gender, peer group which ...

  20. Art approaches and techniques in surrealism

    OpenAIRE

    Novak, Anita

    2013-01-01

    In my thesis I have chosen theme of surrealism. The emphasis is on representation of surrealistic visual techniques and developement. At researching of those visual techniques, I represented main artists who were their inventors. In my thesis, I also explained historical overview of surrealistic movement, it's art techniques and approaches. One of the first most important art approaches was automatism and with that approach flourished set of new visual methods, techniques and mind games,...

  1. Mental Effort and Safety in Curved Approaches

    OpenAIRE

    Entzinger, Jorg Onno; Uemura, Tsuneharu; Suzuki, Shinji

    2014-01-01

    Curved approach procedures are implemented around the world. Although typically flown by the autopilot, human pilots need the situational awareness and skills to take over control in rare-event cases to ensure flight safety. We try to understand the pilot’s cognitive models and differences in required (mental) effort between conventional straight-in approaches and curved approaches. We developed various methods to visualize pilots’ control efforts during manual flight, show their capabilities...

  2. Information Security Awareness: An Innovation Approach

    OpenAIRE

    Corona, Carlos Orozco

    2010-01-01

    Scholars and security practitioners seem to converge in the understanding that Information Security is in great part a problem about people; hence the need for a more holistic approach in order to understand human behaviour in the Information Security field which requires a multidisciplinary approach. Recent events such as the “Interdisciplinary Workshop on Security and Human Behaviour” hosted in Boston, Massachusetts in June 2008, are considering this approach and they have conveyed a multi...

  3. A Hybrid Approach to Clinical Question Answering

    Science.gov (United States)

    2014-11-01

    participation in TREC, we submitted a single run using a hybrid Natural Language Processing ( NLP )-driven approach to accomplish the given task. Evaluation re...for the CDS track uses a variety of NLP - based techniques to address the clinical questions provided. We present a description of our approach, and...discuss our experimental setup, results and eval- uation in the subsequent sections. 2 Description of Our Approach Our hybrid NLP -driven method presents a

  4. Investment Portfolio Evaluation by the Fuzzy Approach

    Directory of Open Access Journals (Sweden)

    Lambovska Maya

    2011-09-01

    Full Text Available This paper presents a new fuzzy approach for the evaluation of investment portfolio, where the approach is viewed by the authors as a sub-phase of the management process of these portfolios. The approach defines the mutual and delayed effects among the significant variables of the investment portfolio. The evaluation of the effects is described as fuzzy trapezoidal numbers and they are aggregated by mathematical operations with incidence matrices and fuzzy functions “experton”.

  5. Comparison of Bayesian and frequentist approaches

    OpenAIRE

    Ageyeva, Anna

    2010-01-01

    The thesis deals with Bayesian approach to statistics and its comparison to frequentist approach. The main aim of the thesis is to compare frequentist and Bayesian approaches to statistics by analyzing statistical inferences, examining the question of subjectivity and objectivity in statistics. Another goal of the thesis is to draw attention to the importance and necessity to teach Bayesian statistics at our University more profound. The thesis includes three chapters. The first chapter prese...

  6. Fuzzy Approach to Statistical Control Charts

    Directory of Open Access Journals (Sweden)

    Shahryar Sorooshian

    2013-01-01

    Full Text Available After investigating the advantages and disadvantages of current methods of statistical process control, it becomes important to overcome the disadvantages and then use the advantages to improve a method for monitoring a process with categorical observations. An approach which considers uncertainty and vagueness is tried for this study; and for this purpose, fuzzy set theory is inevitable to use. So, a new approach based on fuzzy set theory is introduced in this research for monitoring attribute quality characteristics. This approach is then compared with the current related approach to see the difference in performance.

  7. Multiperipheral and polyperipheral approaches to pionization

    CERN Document Server

    Bishari, M; Nussinov, S

    1972-01-01

    Introduction of Regge trajectories in addition to the pomeron, which appears in Mueller's approach to pionization, is shown to predict a small dip. The analysis is motivated by a multiperipheral approach. The question whether this approach may lead to an understanding of the peak in the pionic distribution or the asymmetry effect is discussed. A new (polyperipheral) approach based on the exchange of several chains is introduced in order to account for the observed effects. It leads naturally to Mandelstam cuts and is compared with a partonic picture. (16 refs).

  8. Transseptal dorsal approaches to the wrist.

    Science.gov (United States)

    Zemirline, Ahmed; Hoël, Gérard; Naïto, Kiyohito; Uguen, Arnaud; Liverneaux, Philippe; Le Nen, Dominique

    2013-04-01

    The dorsal approach to the wrist is the exposure of choice for most of the surgical procedures on the radiocarpal and intercarpal joints. Contrary to the volar approach, it encounters neither the main arteries nor the motor nerve branch. However, the dorsal approach goes necessarily through the extensor retinaculum. We describe two transseptal dorsal approaches that pass through the extensor retinaculum in the thickness of a septum between two compartments. A virtual space was developed beneath the infratendinous retinaculum (which is a deep layer covering the floor of the extensor compartments) to expose the periosteum, the ligaments and the joint capsule without opening the extensor compartments. Twenty cadaveric wrists have been dissected to study the feasibility of the two transseptal approaches. Ten wrists were exposed through a 3-4 transseptal approach, passing through the extensor retinaculum in the thickness of the septum between the third and fourth compartments. Ten wrists were exposed through a 4-5 transseptal approach, passing through the extensor retinaculum in the thickness of the septum between the fourth and fifth compartments. The extent of violations of extensor compartments and joint capsule, and the exposed anatomical structures were noted. At the end of each dissection, the whole extensor system was outrightly removed for histological study. The feasibility of the transseptal approaches was demonstrated for all the dissected wrists. The dissection plane beneath the infratendinous retinaculum was macroscopically and microscopically highlighted. The transseptal approaches provide a good exposure to the dorsal side of the wrist joint, without opening the extensor tendon compartments.

  9. Bioequivalence approach for whole effluent toxicity testing

    Energy Technology Data Exchange (ETDEWEB)

    Shukla, R.; Wang, Q.; Fulk, F.; Deng, C.; Denton, D.

    2000-01-01

    Increased use of whole effluent toxicity (WET) tests in the regulatory arena has brought increased concern over the statistical analysis of WET test data and the determination of toxicity. One concern is the issue of statistical power. A number of WET tests may pass the current hypothesis test approach because they lack statistical power to detect relevant toxic effects because of large within-test variability. Additionally, a number of WET tests may fail the current approach because they possess excessive statistical power, as a result of small within-test variability, and detect small differences that may not be biologically relevant. The strengths and limitations of both the traditional hypothesis test approach and the bioequivalence approach for use in the National Pollutant Discharge Elimination System program were evaluated. Data from 5,213 single-concentration, short-term chronic WET tests with Ceriodaphnia dubia provided the database for analysis. Comparison of results between the current approach and the bioequivalence approach indicates that the current approach to WET testing is generally sound but that adopting the proposed bioequivalence approach resolves concerns of statistical power. Specifically, within this data set, applying the bioequivalence approach resulted in failure for tests with relatively large test variability and a pass for tests with relatively small within-test variability.

  10. Percutaneous approaches to mitral valve disease

    National Research Council Canada - National Science Library

    Fassa, A-A; Himbert, D; Brochet, E; Bouleti, C; Vahanian, A

    2015-01-01

    Percutaneous approaches to mitral valve disease consist in modifications of existing surgical techniques, aiming to replicate the favourable outcomes of surgery, with less procedure-related risk, due...

  11. Global energy modeling - A biophysical approach

    Energy Technology Data Exchange (ETDEWEB)

    Dale, Michael

    2010-09-15

    This paper contrasts the standard economic approach to energy modelling with energy models using a biophysical approach. Neither of these approaches includes changing energy-returns-on-investment (EROI) due to declining resource quality or the capital intensive nature of renewable energy sources. Both of these factors will become increasingly important in the future. An extension to the biophysical approach is outlined which encompasses a dynamic EROI function that explicitly incorporates technological learning. The model is used to explore several scenarios of long-term future energy supply especially concerning the global transition to renewable energy sources in the quest for a sustainable energy system.

  12. Probabilistic approach to earthquake prediction.

    Directory of Open Access Journals (Sweden)

    G. D'Addezio

    2002-06-01

    Full Text Available The evaluation of any earthquake forecast hypothesis requires the application of rigorous statistical methods. It implies a univocal definition of the model characterising the concerned anomaly or precursor, so as it can be objectively recognised in any circumstance and by any observer.A valid forecast hypothesis is expected to maximise successes and minimise false alarms. The probability gain associated to a precursor is also a popular way to estimate the quality of the predictions based on such precursor. Some scientists make use of a statistical approach based on the computation of the likelihood of an observed realisation of seismic events, and on the comparison of the likelihood obtained under different hypotheses. This method can be extended to algorithms that allow the computation of the density distribution of the conditional probability of earthquake occurrence in space, time and magnitude. Whatever method is chosen for building up a new hypothesis, the final assessment of its validity should be carried out by a test on a new and independent set of observations. The implementation of this test could, however, be problematic for seismicity characterised by long-term recurrence intervals. Even using the historical record, that may span time windows extremely variable between a few centuries to a few millennia, we have a low probability to catch more than one or two events on the same fault. Extending the record of earthquakes of the past back in time up to several millennia, paleoseismology represents a great opportunity to study how earthquakes recur through time and thus provide innovative contributions to time-dependent seismic hazard assessment. Sets of paleoseimologically dated earthquakes have been established for some faults in the Mediterranean area: the Irpinia fault in Southern Italy, the Fucino fault in Central Italy, the El Asnam fault in Algeria and the Skinos fault in Central Greece. By using the age of the

  13. Democratic approaches to environmental education: Dream or ...

    African Journals Online (AJOL)

    Research indicates that few teachers are currently using a democratic approach to teaching in environmental education even though much of the environmental education literature supports and encourages such an approach. Various explanations are offered for this situation although all agree that the principles, goals and ...

  14. Book Review: Organizations: A Systems Approach

    DEFF Research Database (Denmark)

    Schoeneborn, Dennis

    2016-01-01

    Review of: Stefan Kühl: Organizations. A Systems Approach (trans. P. Schmitz). Farnham: Gower Publishing, 2013. 195 pp. £14.99. ISBN 9781472413413.......Review of: Stefan Kühl: Organizations. A Systems Approach (trans. P. Schmitz). Farnham: Gower Publishing, 2013. 195 pp. £14.99. ISBN 9781472413413....

  15. Student center approach in maths and sc

    African Journals Online (AJOL)

    User

    implementation of student- centered approach across subjects, schools and grade levels? Objective of the study. Generally, this study attempted to assess ... literatures on student centered approach and related articles with similar topics were assessed in order to set framework for the study. These are Yore (2001); Saleh.

  16. Promotion of Agricultural Innovation Systems Approach: Policy ...

    African Journals Online (AJOL)

    delivery for maize production in Morogoro and Dodoma Regions of Tanzania using Agricultural. Innovation Systems (AIS) Approach. Maize productivity in Tanzania is low in spite of its importance to the country's food security and economic well-being of farmers. New approaches to extension and advisory service delivery ...

  17. Organizational design approaches in management consulting

    NARCIS (Netherlands)

    Visscher, Klaasjan; Visscher-Voerman, Irene

    2010-01-01

    Purpose: The purpose of this paper is to map the variety in organizational design approaches, to clarify their differences, and to find out what constitutes good designing in practice. - Design/methodology/approach: A series of in-depth interviews with experienced, high-reputation consultants is

  18. A POMDP approach to Affective Dialogue Modeling

    NARCIS (Netherlands)

    Bui Huu Trung, B.H.T.; Poel, Mannes; Nijholt, Antinus; Zwiers, Jakob; Keller, E.; Marinaro, M.; Bratanic, M.

    2007-01-01

    We propose a novel approach to developing a dialogue model that is able to take into account some aspects of the user's affective state and to act appropriately. Our dialogue model uses a Partially Observable Markov Decision Process approach with observations composed of the observed user's

  19. An instrumental approach to deception in bargaining

    NARCIS (Netherlands)

    Koning, Lukas Frederik

    2011-01-01

    Deception is often described as a form of unethical behavior, yet it is frequently used in bargaining. This raises the question why people use deception in bargaining. In this dissertation an instrumental approach to deception is presented to help answer this question. In an instrumental approach,

  20. Reconsidering Graduate Employability: The "Graduate Identity" Approach.

    Science.gov (United States)

    Holmes, Len

    2001-01-01

    Elaborates a cogent alternative to the skills agenda as an approach to graduate employability--the graduate identity approach. Using a conceptual and theoretical examination of the key notion of performance, presents the twin concepts of practices and identity as significant for understanding human behavior. Offers suggestions for curriculum…

  1. Trialing a contextual approach to academic honesty.

    Science.gov (United States)

    Coffey, Sue; Anyinam, Charles

    2012-01-01

    Concerns about academic honesty in higher education are widespread. To address this issue, faculty took part in a 3-year trial of a highly successful approach to academic honesty. Guiding this approach were an appreciation of student context, faculty orientation to student engagement, and available antiplagiarism technology.

  2. A Ricoeurian Approach to Rhetorical Criticism.

    Science.gov (United States)

    Warnick, Barbara

    1987-01-01

    Proposes an approach to rhetorical criticism that features the relationship between a message and a culturally distanced interpreter or critic. Applies Paul Ricoeur's critical approach to an interpretation of the Gettysburg Address to illustrate how hermeneutics reveals the underlying meaning and cultural significance of enduring texts. (NKA)

  3. Comparison between Fisherian and Bayesian approach to ...

    African Journals Online (AJOL)

    ... the Bayesian approach assigns an observed unit to a group with the greatest posterior probability. Fisher's linear discriminant analysis though is the most widely used method of classification because of its simplicity and optimality properties is normally used for two group cases. However, Bayesian approach is found to ...

  4. Machine Learning Approaches for Music Information Retrieval

    OpenAIRE

    Li, Tao; Ogihara, Mitsunori; Shao, Bo; DingdingWang,

    2009-01-01

    We discussed the following machine learning approaches used in music information retrieval: (1) multi-class classification methods for music genre categorization; (2) multi-label classification methods for emotion detection; (3) clustering methods for music style identification; and (4) semi-supervised learning methods for music recommendation. Experimental results are also presented to evaluate the approaches.

  5. Toward an Integrated Psychological Approach - Phase II

    International Development Research Centre (IDRC) Digital Library (Canada)

    Trauma, Development and Peacebuilding : Toward an Integrated Psychological Approach - Phase II. Over the past decade, the peace, conflict and development community has begun to question the value of medicalized approaches such as post-traumatic stress disorder (PTSD) in dealing with aftermath of political violence ...

  6. Combined Approach for Solving the Electromagnetic Induction ...

    African Journals Online (AJOL)

    Inverse electromagnetic induction is an imaging technique for reconstructing the conductivity and permeability distributions in a region of interest from measurements of impedance made at its boundary. In general, there are two approaches to the reconstruction problem: the pixel-based approach and the parameter-based ...

  7. A Balanced Approach to Early Childhood Education.

    Science.gov (United States)

    Lodish, Richard

    1996-01-01

    Based on 30 years' experience, the author advocates a balanced approach that accommodates extremes in four important areas: curriculum, teaching, structure, and classroom management. Using a whole-language approach to reading should not mean that phonics, spelling, or punctuation skills can't be taught. Authoritarian and open classroom structures…

  8. Theoretical Approaches to the College Environment

    Science.gov (United States)

    Baird, Leonard L.

    1978-01-01

    There is a need for theories of how college environments operate. Criteria for theories are proposed, with emphasis on the production of testable theoretical predictions. Three approaches appear unusually promising: role theory, organizational psychology, and social ecological analysis. The advantages of using such theoretical approaches are…

  9. An Ethnographic Descriptive Approach to Video Microanalysis

    DEFF Research Database (Denmark)

    Holck, Ulla

    2007-01-01

    In the ethnographically informed approach to observational research one studies everyday settings, and seeks to understand actions and meanings in their social context (Silverman 1993; Wolcott 1990). This approach is a strong tool for investigating interactions of a more or less implicit character...

  10. Evaluation and Opportunities in Overtraining Approaches

    Science.gov (United States)

    Roose, Jolanda; de Vries, Wouter R.; Schmikli, Sandor L.; Backx, Frank J. G.; van Doornen, Lorenz J. P.

    2009-01-01

    Overtraining (OT) as a sports phenomenon can be caused by stressors on various levels (physical, emotional, psychological, and social) and evokes responses on these levels. This study evaluated research and new opportunities in the field of OT by introducing an integrated multidisciplinary approach, based on the single and multistressors approach.…

  11. Neuroevolutional Approach to Cerebral Palsy and Speech.

    Science.gov (United States)

    Mysak, Edward D.

    Intended for cerebral palsy specialists, the book emphasizes the contribution that a neuroevolutional approach to therapy can make to habilitation goals of the child with cerebral palsy and applies the basic principles of the Bobath approach to therapy. The first section discusses cerebral palsy as a reflection of disturbed neuro-ontogenisis and…

  12. Competence: Conceptual Approach and Practice in France

    Science.gov (United States)

    Le Deist, Francoise

    2009-01-01

    Purpose: The purpose of this article is to analyse the conceptual approaches to competence and practice in competence management in France. Design/methodology/approach: Extensive literature review, discussion with academic experts in the French competence network of AGRH and interviews concerning developments following the 2003 national agreement…

  13. ECOSYSTEM APPROACH TO FISHERIES MANAGEMENT IN THE ...

    African Journals Online (AJOL)

    A workshop was held in Cape Town in December 2002 to introduce the concept of an ecosystem approach to fisheries (EAF) management in the southern Benguela, and to examine the options for implementing an EAF in. South Africa. The workshop considered alternative modelling approaches that may have potential for ...

  14. Discursive Study of Religion : Approaches, Definitions, Implications

    NARCIS (Netherlands)

    von Stuckrad, Kocku

    2013-01-01

    The article explores recent approaches to historical analysis of discourse that have been developed in disciplines such as the sociology of knowledge and historical epistemology. These approaches have only sporadically been taken seriously in the academic study of religion, although they have a

  15. Managing three approaches to organizational behaviour for ...

    African Journals Online (AJOL)

    approaches is Preventive Manager Behaviour (PMB). This addresses a situation where, because a manager lacks foresight to prevent a problem or nip it in the bud, the organization performs poorly. Another approach is Maintenance Manager Behaviour (MMB) which addresses a situation where, because a manager ...

  16. A network approach toward literature review

    NARCIS (Netherlands)

    van de Wijngaert, Lidwien; Bouwman, Harry; Contractor, Noshir

    2012-01-01

    This study introduces a method that uses a network approach towards literature review. To employ this approach, we use hypotheses proposed in scientific publications as building blocks. In network terms, a hypothesis is a directed tie between two concepts or nodes. The network emerges by aggregating

  17. A Market Failure Approach to Linguistic Justice

    Science.gov (United States)

    Robichaud, David

    2017-01-01

    This paper will consider language management from the perspective of efficiency, and will set the grounds for a new approach to linguistic justice: a market failure approach. The principle of efficiency emphasises the need to satisfy individuals' preferences in an optimal way. Applying this principle with regard to language would justify language…

  18. The Functional Approach to Curriculum Design.

    Science.gov (United States)

    Yalden, Janice

    1979-01-01

    Reviews Wilkins' approach to curriculum design as presented in his "Notional Syllabuses." Discusses three components of the language teaching-language learning process: the semantic, the functional, and the formal component, showing how Wilkins' analytic approach implies a semantic rather than a grammatical syllabus, based on learners'…

  19. An Agile Course-Delivery Approach

    Science.gov (United States)

    Capellan, Mirkeya

    2009-01-01

    In the world of software development, agile methodologies have gained popularity thanks to their lightweight methodologies and flexible approach. Many advocates believe that agile methodologies can provide significant benefits if applied in the educational environment as a teaching method. The need for an approach that engages and motivates…

  20. Pluralistic Approaches to Languages in the Curriculum

    DEFF Research Database (Denmark)

    Daryai-Hansen, Petra; Gerber, Brigitte; Lörincz, Ildikó

    2015-01-01

    European Framework of Reference for Languages (CEFR) scales. The paper introduces to the Framework of Reference for Pluralistic Approaches to Languages and Cultures (FREPA). Pluralistic approaches use teaching and learning activities involving several (i.e. more than one) varieties of language, e...

  1. The "Rear-View Mirror" Approach.

    Science.gov (United States)

    Nord, James

    1987-01-01

    The "rear-view mirror" approach referred to by McLuhan refers to new media being used with the methods of older, different media. A Sens-it (SENtence- SENtence- SITuation) cell model is suggested as an effective use of interactive videodisk systems in contrast to the communicative competence approach. (Author/LMO)

  2. Teaching Science through a Systems Approach

    Science.gov (United States)

    Llewellyn, Douglas; Johnson, Scott

    2008-01-01

    Based on the recommendation of the AAAS and the NRC, middle level science is the rightful introduction for a systems approach, including the study of its parts, subsystems, interconnections, and interrelationships. Dr. Seuss's "The Lorax" provides an excellent opportunity to combine ecological consequences within a systems approach (Sweeney 2001).…

  3. [Extended endoscopic endonasal approach to skull base].

    Science.gov (United States)

    López-Arbolay, Omar; González-González, Justo; Rojas-Manresa, Jorge Luis

    2012-11-01

    Different approaches to the skull base have been developed through the sphenoidal sinus. Traditional boundaries of the trans-sphenoidal approach can be extended in antero-posterior and lateral plane. We review our experience with extended endoscopic endonasal approach in 127 cases. We used the extended endoscopic endonasal approach in 127 patients with different lesions of the skull base. This study specifically focuses on: type of lesions, surgical approach, outcome and surgical complications. Extended endoscopic endonasal approach was used in 127 patients with following lesions: 61 invasive adenomas to cavernous sinus, 10 clival chordomas, 21 craniopharyngiomas, 26 meningiomas, 4 cerebrospinal fluid leakages, one meningoencephalocele, 2 malignan lesions and 2 thyroid ophthalmopathy. In tumoral lesions gross total resection was achieved in 82.5%, with better results in craniopharyngiomas 90.5%, followed by invasive adenomas with 85.2%, and meningiomas with 84.6%. The most frequent complications were the insipid (8.6%) diabetes, meningoencefalitis (3.9%) and the hydrocephalic (3.9%). Mortality was 3.9%. The extended endoscopic endonasal approach is a promising minimally invasive alternative for selective cases with skull base lesions. As techniques and technology advance this approach may become the procedure of choice for most lesions and should be considered an option in the management of the patients with these complex pathologies by skull base surgeon. Copyright © 2012 Sociedad Española de Neurocirugía. Published by Elsevier España. All rights reserved.

  4. A Progressive Approach to Content Generation

    DEFF Research Database (Denmark)

    Shaker, Mohammad; Shaker, Noor; Togelius, Julian

    2015-01-01

    PCGapproachesarecommonlycategorisedasconstructive,generate- and-test or search-based. Each of these approaches has its distinctive advantages and drawbacks. In this paper, we propose an approach to Content Generation (CG)– in particular level generation – that combines the advantages of construc...

  5. Amartya Sen's Capability Approach and Education

    Science.gov (United States)

    Walker, Melanie

    2005-01-01

    The human capabilities approach developed by the economist Amartya Sen links development, quality of life and freedom. This article explores the key ideas in the capability approach of: capability, functioning, agency, human diversity and public participation in generating valued capabilities. It then considers how these ideas relate specifically…

  6. A Heuristic Approach to Scheduling University Timetables.

    Science.gov (United States)

    Loo, E. H.; And Others

    1986-01-01

    Categories of facilities utilization and scheduling requirements to be considered when using a heuristic approach to timetabling are described together with a nine-step algorithm and the computerized timetabling system, Timetable Schedules System (TTS); TTS utilizes heuristic approach. An example demonstrating use of TTS and a program flowchart…

  7. Dialogic approaches to the study of subjectivity

    DEFF Research Database (Denmark)

    Otrel-Cass, Kathrin

    2013-01-01

    Book review: Sullivan, P. (2012). Qualitative Data Analysis: Using a dialogic approach. Los Angeles: SAGE Publications Ltd. ISBN 978-1-84920-609-9......Book review: Sullivan, P. (2012). Qualitative Data Analysis: Using a dialogic approach. Los Angeles: SAGE Publications Ltd. ISBN 978-1-84920-609-9...

  8. Matrix approach to modelling of SAR signals

    NARCIS (Netherlands)

    Lidicky, L.; Hoogeboom, P.

    2005-01-01

    The paper presents a matrix approach to implementation of SAR signal generating and processing schemes. This approach is advantageous when matrix oriented software such as Matlab is used. Algorithms written in this type of software packages run faster compared to the same algorithms written for the

  9. A systems approach framework for coastal zones

    DEFF Research Database (Denmark)

    Hopkins, Tom Sawyer; Bailly, Denis; Støttrup, Josianne

    2011-01-01

    This Special Feature Volume examines the potential value of the Systems Approach Framework (SAF) as a methodological framework for the transition to sustainable development in coastal zones. This article provides insight on the Systems Approach, the theory behind it, and how its practical applica...

  10. Instructional Approaches in Teaching the Holocaust

    Science.gov (United States)

    Lindquist, David H.

    2011-01-01

    Holocaust education requires teachers to carefully determine which instructional approaches ensure effective teaching of the subject while avoiding potential difficulties. The article identifies several complicating factors that must be considered when making pedagogical decisions. It then examines five methodological approaches that can be used…

  11. The livelihood approach: A critical exploration

    NARCIS (Netherlands)

    L.J. de Haan (Leo)

    2012-01-01

    textabstractThe livelihood approach is an important actor-oriented perspective in development studies, including geography of development, which strongly influenced development oriented research and development practice. This paper deals with the original outlines of that approach and its subsequent

  12. "1984": A Confessional Reading and Teaching Approach.

    Science.gov (United States)

    Tanenbaum, Miles

    1989-01-01

    Describes an approach to teaching George Orwell's "1984," emphasizing the main characters' struggles through the themes of innocence and experience, conformity and rebellion, love and hate, discovery and creation, and death. Notes that this reader-response approach forces students into the process of self-examination. (MM)

  13. Promoting School Connectedness through Whole School Approaches

    Science.gov (United States)

    Rowe, Fiona; Stewart, Donald; Patterson, Carla

    2007-01-01

    Purpose: The purpose of this paper is to develop a framework to demonstrate the contribution of whole school approaches embodied by the health-promoting school approach, to the promotion of school connectedness, defined as the cohesiveness between diverse groups in the school community, including students, families, school staff and the wider…

  14. Climate adaptation approaches and key policy characteristics

    NARCIS (Netherlands)

    Vij, Sumit; Moors, Eddy; Ahmad, Bashir; Uzzaman, Arfan; Bhadwal, Suruchi; Biesbroek, Robbert; Gioli, Giovanna; Groot, Annemarie; Mallick, Dwijen; Regmi, Bimal; Saeed, Basharat Ahmed; Ishaq, Sultan; Thapa, Bhuwan; Werners, Saskia E.; Wester, Philippus

    2017-01-01

    This paper analyses and assesses how existing policies and approaches in South Asia consider long-term climate change adaptation. Presently, it is unclear what approaches are used in the existing policies to cope with the future climatic changes. Our research framework consists of two components.

  15. ECOSYSTEM APPROACH TO FISHERIES MANAGEMENT IN THE ...

    African Journals Online (AJOL)

    Some of the possible reasons are the effect of environmental variability on some stocks, ecosystem effects of fishing and unforeseen trophic interaction effects. To date, fisheries management has been based largely on a single-stock approach, but Namibia is committed to implement, in addition, an ecosystem approach to ...

  16. The Social Shaping Approach to Technology Foresight

    DEFF Research Database (Denmark)

    Jørgensen, Michael Søgaard; Jørgensen, Ulrik; Clausen, Christian

    2009-01-01

    The social shaping of technology (SST) approach has been developed as a response and extension to the ideas of techno-economic rationality and linear conceptions of technology development and its consequences. The SST approach seems especially promising in areas of technology where visions are ma...

  17. [Suture tip plasty using an endonasal approach].

    Science.gov (United States)

    Tasman, A-J; Palma, P

    2010-09-01

    Over the last two decades, the use of the external approach for primary and secondary rhinoplasties has become increasingly popular. This article illustrates the versatility of endonasal techniques for the correction of nasal tip deformities on the basis of four cases. The approach to the nasal tip and the chosen technique as used in 100 consecutive rhinoplasties were reviewed. For primary and revision tip plasty, endonasal approaches were used in 81% of cases. Preferred incisions were the infracartilaginous approach and the transfixion incision. Using these approaches, correction of the tip was achieved by using sutures to reposition and reshape the alar cartilages and the columella without grafts to the nasal tip in most cases. Nasal tip plasty via endonasal approaches using sutures is technically more challenging compared to the external approach with its superior exposure. This drawback is outweighed by less operating time and faster patient recovery. Contrary to the general trend, the authors believe that endonasal tip plasty techniques using sutures can obviate the external approach and grafts in many cases and should form an integral part of the rhino-surgeon's repertoire.

  18. Transition Studies: Basic Ideas and Analytical Approaches

    NARCIS (Netherlands)

    Grin, J.; Brauch, H.G.; Oswald Spring, Ú.; Grin, J.; Scheffran, J.

    2016-01-01

    As a background to later contributions, this chapter provides a concise introduction to different approaches to (i) understanding and (ii) shaping transition dynamics: (1) A sociotechnical approach, with the multilevel perspective as its main concept, and strategic niche management as its governance

  19. Accident prevention in a contextual approach

    DEFF Research Database (Denmark)

    Dyhrberg, Mette Bang

    2003-01-01

    of such a contextual approach is shortly described and demonstrated in relation to a Danish case on accident prevention. It is concluded that the approach presently offers a post-ante, descriptive analytical understanding, and it is argued that it can be developed to a frame of reference for planning actions...

  20. Analysis of landing gear noise during approach

    NARCIS (Netherlands)

    Merino Martinez, R.; Snellen, M.; Simons, D.G.

    2016-01-01

    Airframe noise is becoming increasingly important during approach, even reaching higher noise levels than the engines in some cases. More people are a_ected due to low ight altitudes and _xed tra_c routing associated with typical approaches. For most air- craft types, the landing gear system is a