bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhancement of electro‐optical properties in holographic polymer‐dispersed liquid crystal films by incorporation of multiwalled carbon nanotubes into a polyurethane acrylate matrix
Authors: Kim Eun Hee , Lee Jae Hyun , Jung Yeon Gil , Paik Ungyu
Published: June 2010

Holographic polymer‐dispersed liquid crystal (HPDLC) films were fabricated with varying amounts of multiwalled carbon nanotubes (MWCNTs) to optimize the electro‐optical performance of the HPDLC films. The MWCNTs were well dispersed in the prepolymer mixture up to 0.5 wt%, implying that polyurethane acrylate (PUA) oligomer chains wrap the MWCNTs along their length, resulting in high diffraction efficiency and good phase separation. The hardness and elastic modulus of the polymer matrix were enhanced with increasing amounts of MWCNTs because of the reinforcement effect of the MWCNTs with intrinsically good mechanical properties. The increased elasticity of the PUA matrix and the immiscibility between the matrix and the liquid crystals (LCs) gradually increased the diffraction efficiency of the HPDLC films. However, the diffraction efficiency of HPDLC films with more than 0.05 wt% MWCNTs was reduced, caused by poor phase separation between the matrix and LCs because of the high viscosity of the reactive mixture. HPDLC films showing a low driving voltage (<3 V µm−1), a fast response time (<10 ms) and a high diffraction efficiency (>75%) could be obtained with 0.05 wt% MWCNTs at 40 wt% LCs. Copyright © 2010 Society of Chemical Industry
Improving the hydrophobic, water barrier and crystallization properties of poly(ethylene terephthalate) by incorporating monodisperse SiO2 particles
Authors: Yangchuan Ke , Yuguo Wang , Li Yang
Published: June 2010

This paper details an improvement in the properties of poly(ethylene terephthalate) (PET) with respect to its use in petroleum engineering by incorporating uniform (monodisperse; 35 to 380 nm) silica (SiO2) particles and polystyreneSiO2 core–shell particles by melt mixing. The resulting high‐performance nanocomposite (SNPET) films are presented. The results of contact angle and water absorption tests showed that the contact angle of the amorphous SNPET films increased from 72° to 118.5° as the core–shell particle load increased from 0 to 6.0 wt%. The contact angle reached 128.0° when the films were annealed. Decreasing the SiO2 particle size demonstrably improved the SNPET film hydrophobicity and lowered the water diffusion coefficient, i.e. SiO2 particles of 35 nm in size gave the greatest enhancement of water barrier properties. Results of transmission electron microscopy, scanning electron microscopy, atomic force microscopy and optical measurements showed the homogeneous particle dispersion and nanostructure in the SNPET films. Their transparency and haziness increased as the particle size decreased. Use of such core–shell structures meant that the uniform (monodisperse) SiO2 particles could be dispersed homogeneously in PET, and effectively improved the surface, thermal and crystallization behavior of SNPET films to produce materials with high barrier stability against water. Copyright © 2010 Society of Chemical Industry
Synthesis and self‐assembly of well‐defined cyclodextrin‐centered amphiphilic A14B7 multimiktoarm star copolymers based on poly(ε‐caprolactone) and poly(acrylic acid)
Authors: Gou Peng‐Fei , Zhu Wei‐Pu , Xu Ning , Shen Zhi‐Quan
Published: June 2010

Novel amphiphilic A14B7 multimiktoarm star copolymers composed of 14 poly(ε‐caprolactone) (PCL) arms and 7 poly(acrylic acid) (PAA) arms with β‐cyclodextrin (β‐CD) as core moiety were synthesized by the combination of controlled ring‐opening polymerization (CROP) and atom transfer radical polymerization (ATRP). 14‐Arm star PCL homopolymers (CDSi‐SPCL) were first synthesized by the CROP of CL using per‐6‐(tert‐butyldimethylsilyl)‐β‐CD as the multifunctional initiator in the presence of Sn(Oct)2 at 125 °C. Subsequently, the hydroxyl end groups of CDSi‐SPCL were blocked by acetyl chloride. After desilylation of the tert‐butyldimethylsilyl ether groups from the β‐CD core, 7 ATRP initiating sites were introduced by treating with 2‐bromoisobutyryl bromide, which further initiated ATRP of tert‐butyl acrylate (tBA) to prepare well‐defined A14B7 multimiktoarm star copolymers [CDS(PCL‐PtBA)]. Their molecular structures and physical properties were in detail characterized by 1H NMR, SEC‐MALLS, and DSC. The selective hydrolysis of tert‐butyl ester groups of the PtBA block gave the amphiphilic A14B7 multimiktoarm star copolymers [CDS(PCL‐PAA)]. These amphiphilic copolymers could self‐assemble into multimorphological aggregates in aqueous solution, which were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM) and atomic force microscopy (AFM). © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2961–2974, 2010
Polymerization and characterization of self‐assembled β‐cyclodextrin‐threaded chiral monomers
Authors: Chiu Yi‐Hong , Liu Jui‐Hsiang
Published: June 2010

A helical inclusion complex polymer was fabricated through the polymerization of β‐cyclodextrin‐threaded chiral monomers. The photo induced polymerization of inclusion complex clusters caused shrinkage of the polymer and decreased the pitches, leading to the disappearance of spring‐like construction under TEM. From the results of circular dichroism of the inclusion complex polymer, the helical construction was confirmed, and an entanglement of the polymer chains is proposed. After removal of the β‐cyclodextrins from the pendant groups of the inclusion complex polymer, the helical structure was found to be maintained. The highly ordered molecular arrangement of β‐cyclodextrins removed from the inclusion complex polymer was confirmed using POM. Here we demonstrate the fabrication of helical polymer fibers composed of entangled polymers through self‐assembled β‐cyclodextrin‐threaded chiral monomers. The helical polymer construction was maintained by the entwisted polymer chains even after the removal of β‐cyclodextrins from the pendant groups of the inclusion complex polymer. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2975–2981, 2010
Synthesis and characterization of sulfonated copolyethersulfones
Authors: Samperi Filippo , Battiato Salvatore , Puglisi Concetto , Asarisi Vincenzo , Recca Antonino , Cicala Gianluca , Mendichi Raniero
Published: June 2010

The present article deals with the synthesis and characterization of some sulfonated copolyethersulfones. The synthetic approach differs from the post sulfonation approach traditionally reported in the literature. The synthetic procedure is based on the use of sulfonated monomers which are then reacted with previously synthesized telechelic hydoxy‐ended poly (ether sulpnone)s. Combining the MALDI‐TOF MS and 1H NMR analyses, with SEC‐Viscometry and TGA measurements, we demonstrate a powerful tool for characterizing the chemical composition, end chains, degree of sulfonation (DS) and molecular mass distribution (MMD) of disulfonated poly(arylene ether‐sulfone) copolymers. The characterization techniques allowed to determine the exact nature of the copolymers synthesized and to reveal some interesting features about the reaction. DMA data show that the glass transition temperature of sulfonated copolymers with similar DS increase as raise their MMD. Copolymers with a DS of 10–11 mol % reach a Tg of 244–246 °C. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3010–3023, 2010
Preparation of α,ω‐telechelic hexyl acrylate polymers with OH, COOH, and NH2 functional groups by RAFT
Authors: Cortez‐Lemus Norma A. , Salgado‐Rodríguez Rodolfo , Licea‐Claveríe Angel
Published: June 2010

The design, synthesis, and use of two new, stable, functionalized chain transfer agents (CTA's) containing OH and amine end groups for the RAFT polymerization is reported: 2‐hydroxyethoxy‐carbonylphenylmethyl dithiobenzoate and 2‐(2‐(tert‐butoxycarbonyl)ethylamino)‐2‐oxo‐1‐phenylethyl benzodithioate, respectively. The RAFT polymerization of n‐hexyl acrylate (HA) using those CTA's, were compared to several other functionalized dithiobenzoate esters reported in the literature containing COOH and Ester groups. The performances of the dithiobenzoates were compared in terms of kinetics and molecular weight distribution control. Good control in polymerization of n‐hexyl acrylate with a linear increase of Mn with conversion mantaining polydispersity indices (PDI) below 1.1 was obtained by use of the new functionalized CTA's developed and also by use of some other CTA's tested, to produce well‐defined linear polymers with one specific chain‐end functionality: OH, COOH or Amine. Using a postpolymerization reaction with functionalized azocompounds in a 5 to 1 ratio, α,ω‐telechelic polymers, with OH or COOH as functional group at the second end were obtained. By using this synthetic strategy α,ω‐homotelechelic and heterotelechelic polymers were readily prepared. The chemical availability of functional end‐groups in the telechelics was demonstrated by reaction with methacrylic anhydride. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3033–3051, 2010
Bioconjugation of D‐glucuronic acid sodium salt to well‐defined primary amine‐containing homopolymers and block copolymers
Authors: Alidedeoglu Alp H. , York Adam W. , Rosado Dale A. , McCormick Charles L. , Morgan Sarah E.
Published: June 2010

The synthesis of well‐defined carboxylic acid‐functionalized glycopolymers prepared via one‐step postpolymerization modification of poly(N‐[3‐aminopropyl] methacrylamide) (PAPMA), a water‐soluble primary amine methacrylamide, in aqueous medium is demonstrated. PAPMA was first polymerized via aqueous reversible addition‐fragmentation chain transfer polymerization in aqueous buffer using 4‐cyanopentanoic acid dithiobenzoate as the chain transfer agent and 4,4′‐azobis(4‐cyanovaleric acid) (V‐501) as the initiator at 70 °C. The resulting well‐defined PAPMA was then conjugated with D‐glucuronic acid sodium salt through reductive amination in alkaline medium (pH 8.5) at 45 °C. The successful bioconjugation was proven through proton (1H) and carbon (13C) nuclear magnetic resonance spectroscopy and matrix‐assisted laser desorption/ionization time of flight mass spectrometry analysis, which indicated near quantitative conversion. A similar bioconjugation reaction was conducted with poly(2‐aminoethyl methacrylate) (PAEMA) and poly(2‐aminoethyl methacrylate‐b‐poly(N‐[2‐hydroxypropyl]methacrylamide) (PAEMA‐b‐PHPMA). For the PAEMA homopolymers and block copolymers, however, lower conversion was obtained, most likely because of degradation reactions of PAEMA in alkaline medium. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3052–3061, 2010
Influence of compatibilizing agent molecular structure on the mechanical properties of phosphate glass fiber‐reinforced PLA composites
Authors: Haque Papia , Barker Ian A. , Parsons Andrew , Thurecht Kristofer J. , Ahmed Ifty , Walker Gavin S. , Rudd Christopher D. , Irvine Derek J.
Published: June 2010

Eight compatibilizing agents were studied to investigate their effect on the quality of the interface between a phosphate glass fiber and a poly(lactic acid) (PLA) matrix. After application of the agents via dip‐coating, the fibers were Soxhlet extracted to remove any unreacted compatibilizer. To assess the interface quality, single fiber tensile tests of treated fibers and interfacial shear strengths (IFSS) of single fiber composites (SFC) were assessed. Of the agents tested, Glycerol‐2‐phosphate disodium pentahydrate (GP) and low molecular weight PLA with a sodium salt terminal group (PLA‐Na) showed the highest IFSS values, which were significantly higher than those of the control. Oligomeric PLA with a carboxylic acid end group and alendronate sodium trihydrate also showed an improvement over the control fibers. The hydrolytic degradation of these single fiber composites was studied over 7 days in water at 37 °C and a significant decrease in IFSS was observed in all cases, with the treated samples dropping to the level of the control. TGA and XPS analysis of the sized fibers showed that GP and PLA‐Na had been applied successfully to the fiber surface. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3082–3094, 2010
Grafting of polyaniline onto the surface of 4‐aminobenzoyl‐functionalized multiwalled carbon nanotube and its electrochemical properties
Authors: Jeon In‐Yup , Kang Sang‐Wook , Tan Loon‐Seng , Baek Jong‐Beom
Published: June 2010

Polyaniline (PANi)‐grafted multiwalled carbon nanotube (MWNT) composite is prepared by a two‐step reaction sequence. MWNT is first functionalized with 4‐aminobenzoic acid in polyphosphoric acid/phosphorous pentoxide as a “direct” Friedel‐Crafts acylation reaction medium. The resultant 4‐aminobenzoyl‐functionalized MWNT is then treated with aniline using ammonium persulfate/aqueous hydrochloric acid to promote a chemical oxidative polymerization, leading to PANi‐grafted MWNT composite. The resultant composite is characterized by elemental analysis, Fourier‐transform infrared spectroscopy, wide‐angle X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, UV–vis absorption spectroscopy, fluorescence spectroscopy, cyclic voltammetry, and electrical conductivity measurement. The thermooxidative stability and electrical conductivity of PANi‐grafted MWNT composite are improved compared to those of PANi. Specifically, the electrical conductivity of PANi‐grafted MWNT is improved 10–900 times depending upon the level of doping. The capacitance of the composite is also greatly enhanced. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3103–3112, 2010
Synthesis of networked polymers with lithium counter cations from a difunctional epoxide containing poly(ethylene glycol) and an epoxide monomer carrying a lithium sulfonate salt moiety
Authors: Matsumoto Kozo , Endo Takeshi
Published: June 2010

Poly(ethylene glycol)‐based networked polymers that had lithium sulfonate salt structures on the network were prepared by heating a mixture of poly(ethylene glycol) diglycidyl ether (PEGGE), poly(ethylene glycol) bis(3‐aminopropyl) terminated (PEGBA), and an ionic epoxy monomer, lithium 3‐glycidyloxypropanesulfonate (LiGPS). Flexible self‐standing networked polymer films showed high thermal stability, low crystallinity, low glass transition temperature, and good mechanical strength. The materials were ion conductive at room temperature even under a dry condition, although the ionic conductivity was rather low (10−6 to 10−5 S/m). The ionic conductivity increased with the increase in temperature to above 1 × 10−4 S/m at 90 °C. The film samples became swollen by immersing in propylene carbonate (PC) or PC solution of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). The samples swollen in PC showed higher ionic conductivity (ca.1 × 10−3 S/m at room temperature), and the samples swollen in LiTFSI/PC showed much higher ionic conductivity (nearly 1 S/m at room temperature). © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3113–3118, 2010
Preparation and characterization of polymer/silica nanocomposites via double in situ miniemulsion polymerization
Authors: Zhang Jianan , Liu Nannan , Wang Mozhen , Ge Xuewu , Wu Mingyuan , Yang Jianjun , Wu Qingyun , Jin Zhilai
Published: June 2010

Polymer/SiO2 nanocomposite microspheres were prepared by double in situ miniemulsion polymerization in the presence of methyl methacrylate, butyl acrylate, γ‐methacryloxy(propyl) trimethoxysilane, and tetraethoxysilane (TEOS). By taking full advantage of phase separation between the growing polymer particles and TEOS, inorganic/polymer microspheres were fabricated successfully in a one‐step process with the formation of SiO2 particles and the polymerization of organic monomers taking place simultaneously. The morphology of nanocomposite microspheres and the microstructure, mechanical properties, thermal properties, and optical properties of the nanocomposite films were characterized and discussed. The results showed that hybrid microspheres had a raspberry‐like structure with silica nanoparticles on the shells of polymer. The silica particles of about 20 nm were highly dispersed within the nanocomposite films without aggregations. The transmittance of nanocomposite film was comparable to that of the copolymer film at around 70–80% from 400 to 800 nm. The mechanical properties and the fire‐retardant behavior of the polymer matrix were improved by the incorporation of silica nanoparticles. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3128–3134, 2010
Superparamagnetic pH‐sensitive multilayer hybrid hollow microspheres for targeted controlled release
Authors: Mu Bin , Liu Peng , Dong Yun , Lu Chunyin , Wu Xueli
Published: June 2010

The superparamagnetic multilayer hybrid hollow microspheres have been fabricated using the layer‐by‐layer assembly technique by the electrostatic interaction between the polyelectrolyte cation chitosan (CS) and the hybrid anion citrate modified ferroferric oxide nanoparticles (Fe3O4‐CA) onto the sacrificial polystyrene sulfonate microspheres templates after etching the templates by dialysis. The saturation magnetization and magnetite contents of the superparamagnetic multilayer hybrid hollow microspheres were 32.46 emu/g and 51.3%, respectively. The hybrid hollow microspheres showed pH‐sensitive characteristics. The adsorption and release of the basic dye (methylene blue) were applied to investigate the interaction between the amino groups of CS and the carboxyl groups of the Fe3O4‐CA nanoparticles in different pH media. The superparamagnetic pH‐sensitive multilayer hybrid hollow microspheres are expected to be used for the targeted controlled release of drugs or in diagnostics. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3135–3144, 2010
Multiwalled carbon nanotubes covalently functionalized with poly(N‐vinylcarbazole) via RAFT polymerization: Synthesis and nonliner optical properties
Authors: Zhang Bin , Wang Jun , Chen Yu , Früchtl Daniel , Yu Bo , Zhuang Xiaodong , He Nan , Blau Werner J.
Published: June 2010

The poly(N‐vinylcarbazole)‐grafted MWNTs (MWNT‐PVK) hybrid materials were synthesized in the presence of S‐1‐Dodecyl‐S′‐(α, α′‐dimethyl‐α″‐acetic acid) trithiocarbonate (DDAT)‐covalently functionalized multiwalled carbon nanotubes (MWNT‐DDAT) as reversible addition–fragmentation chain transfer (RAFT) agent. Incorporation of the PVK moieties onto the MWNTs surface can considerably improve the solubility and processability of MWNTs. For all MWNT‐PVK hybrid materials, they are soluble in some common organic solvents such as toluene, THF, chloroform, DMF and others. In contrast to the UV/Vis spectrum of DDAT‐PVK, which was synthesized by use of DDAT as RAFT agent under the same synthetic condition, in the visible region, the absorption spectrum of MWNT‐PVK exhibited a typical electronic absorption characteristics of solubilized carbon nanotubes, in which the absorbance decreases gradually in the range of 350–600 nm. At the same level of linear transmission the MWNT‐PVK with 79.2% PVK moieties in the material structure possesses best optical limiting performance in comparison with the other MWNT‐PVK composites, MWNTs and C60. The significant NLO responses manifest the MWNT‐PVK materials suitable candidate for viable optical limiting devices. Light scattering, originating from the thermal‐induced microplasmas and/or microbubbles, is responsible for the optical limiting. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3161–3168, 2010
Synthesis, characterization, and molecular recognition of sugar‐functionalized nanoparticles prepared by a combination of ROP, ATRP, and click chemistry
Authors: Jubeli Emile , Moine Laurence , Barratt Gillian
Published: June 2010

The aim of this work was to prepare nanoparticles bearing sugar residues at their surface through the synthesis of amphiphilic block copolymer of poly d,l‐lactide (PLA) and poly(ethylene glycol)methacrylate, with the hydrophilic part terminating with glucopyranoside molecules as a model for any carbohydrate ligand. The construction was achieved by a combination of click chemistry, ring‐opening polymerization, and atom transfer radical polymerization. The modified monomer and resulting copolymer were characterized by NMR, SEC, and FTIR. Nanoparticles with a mean hydrodynamic diameter of <200 nm as determined by quasi‐elastic light scattering were prepared from the amphiphilic copolymer by nanoprecipitation using dimethylformamide (DMF) as water‐miscible solvent. In the range of 2.5–10 mg copolymer/mL DMF, the polymer concentration did not have much effect on the size of the nanoparticles. Accessibility of glucopyranoside molecules on the surface of the nanoparticles was confirmed by formation of aggregates from nanoparticles in the presence of concanavalin A observed by transmission electronic microscopy. Finally, no significant cytotoxicity toward human umbilical vein endothelial cells was detected for the final nanoparticles. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3178–3187, 2010
Direct synthesis of terminally “clickable” linear and hyperbranched polyesters
Authors: Ramkumar S. G. , Rose K. A. Amala , Ramakrishnan S.
Published: June 2010

1,3‐Dipolar cycloaddition of an organic azide and an acetylenic unit, often referred to as the “click reaction”, has become an important ligation tool both in the context of materials chemistry and biology. Thus, development of simple approaches to directly generate polymers that bear either an azide or an alkyne unit has gained considerable importance. We describe here a straightforward approach to directly prepare linear and hyperbranched polyesters that carry terminal propargyl groups. To achieve the former, we designed an AB‐type monomer that carries a hydroxyl group and a propargyl ester, which upon self‐condensation under standard transesterification conditions yielded a polyester that carries a single propargyl group at one of its chain‐ends. Similarly, an AB2 type monomer that carries one hydroxyl group and two propargyl ester groups, when polymerized under the same conditions yielded a hyperbranched polymer with numerous “clickable” propargyl groups at its molecular periphery. These propargyl groups can be readily clicked with different organic azides, such as benzyl azide, ω‐azido heptaethyleneglycol monomethylether or 9‐azidomethyl anthracene. When an anthracene chromophore is clicked, the molecular weight of the linear polyester could be readily estimated using both UV–visible and fluorescence spectroscopic measurements. Furthermore, the reactive propargyl end group could also provide an opportunity to prepare block copolymers in the case of linear polyesters and to generate nanodimensional scaffolds to anchor a variety of functional units, in the case of the hyperbranched polymer. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3200–3208, 2010
Complex pH‐ and temperature‐sensitive swelling behavior of mixed polymer brushes
Authors: Bittrich Eva , Kuntzsch Marco , Eichhorn Klaus‐Jochen , Uhlmann Petra
Published: June 2010

The ability of a mixed polymer brush consisting of poly(N‐isopropyl acrylamide) (PNIPAAM) and poly(acrylic acid) (PAA) to modify physicochemical interfacial properties is presented. The answer of the binary brush toward changes of environmental conditions like temperature, salt concentration, and pH value was investigated by in situ spectroscopic VIS‐ellipsometry as well as AFM and contact angle mesurements in the dry state and compared with the behavior of the corresponding homopolymer brushes. A coupled swelling of PNIPAAm and PAA could be found, leading to a complex pH‐, salt‐, and temperature‐sensitive swelling behavior of these mixed brushes, also depending on the composition of the brush. The complex interaction of the two polymers resulted in new properties of the mixed system. Although the temperature sensitivity of the mixed system was decreased compared with that of the corresponding PNIPAAM brushes, the sensitivity toward pH and salt concentration was amplified compared with that of pure PAA brushes. Additionally it is shown that in spite of the decreased temperature sensitivity of the mixed brush, a temperature‐dependent adsorption of human serum albumin was observed whereas an increased adsorption affinity was found that is not predictable from the adsorption affinity of the corresponding homopolymer brushes. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1606–1615, 2010
Synthesis and chemical modification of magnetic nanoparticles covalently bound to polystyrene‐SiCl2‐poly(2‐vinylpyridine)
Authors: Serrano‐Ruiz David , Rangou Sofia , Avgeropoulos Apostolos , Zafeiropoulos Nikolaos E. , López‐Cabarcos Enrique , Rubio‐Retama Jorge
Published: June 2010

The present article offers a new approach to create a multifunctional material based on magnetic nanoparticles, which can be dispersed in aqueous and organic media. The preparation of this material was performed by binding covalently polymer chains based on a reactive diblock‐copolymer of the polystyrene‐SiCl2‐poly(2‐vinylpyridine) type, with average molecular weight per number (Mn) equal to 14,700 g/mol and a polydispersity index (PDI) less than 1.1, onto the surface of γ‐Fe2O3 magnetic nanoparticles. The dichlorosilane moiety of the diblock‐copolymer reacted with the OH groups of the magnetic nanoparticles immobilizing the polymer chain onto its surface. This reaction was monitored by FTIR and the polymer grafting density was determined by TGA and BET. Dynamic light scattering revealed that the hydrodynamic diameter of the nanoparticles increased after immobilizing the polymer. Contact angle measurements demonstrated the ability of the hybrid material to interact with organic and aqueous media allowing its dispersion in solvents with different polarities. This property was used to prepare a magnetically active emulsion. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1668–1675, 2010
Inorganic/organic polymer coatings for textiles to realize water repellent and antimicrobial properties—A study with respect to textile comfort
Authors: Mahltig B. , Fischer A.
Published: June 2010

SiO2 coatings and inorganic/organic polymer hybrid coatings were applied onto textiles, and the textile properties were investigated with respect to parameters of textile comfort as stiffness, water uptake, and air permeability. Two different types of textiles (viscose and polyamide) were dip‐coated with coating solutions of a pure silica sol and a polymer‐modified silica sol. Only with low concentrated coating solutions a sufficient low stiffness and therefore an appropriate textile comfort could be realized. Analogously the water uptake of the treated textiles was decreased and sufficient high values were only reached with highly diluted coating solutions. Therefore, it was investigated whether such diluted coating solutions could be used for modification of textiles to add new beneficial properties. To reach hydrophobic textile properties one sol was modified with perfluorooctyltriethoxysilane. For antimicrobial functionalization a second sol was modified with silver. It was shown, for the application of new textile properties like water repellency or antimicrobial activity only concentrations ≤1% were necessary. In this case, the increase of textile stiffness was appropriate low, so the textile comfort was preserved while new functional properties were applied. Therefore, the presented diluted coating agents could be appropriate means for textile refinement and offer new textile applications. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1562–1568, 2010
Inhibition of 5α‐reductase enhances testosterone‐induced expression of U19/Eaf2 tumor suppressor during the regrowth of LNCaP xenograft tumor in nude mice
Authors: Gupta Shubham , Wang Yujuan , Ramos‐Garcia Raquel , Shevrin Daniel , Nelson Joel B , Wang Zhou
Published: June 2010

BACKGROUND

Intermittent androgen deprivation therapy (IADT) was developed to improve the quality of life and retard prostate cancer progression to castration resistance. IADT involves regrowth of the tumor during the off cycle upon testosterone recovery. Our previous studies showed that testosterone is more potent than dihydrotestosterone (DHT) in the induction of a subset of androgen‐responsive genes during rat prostate regrowth. However, it is not clear if the same phenomenon would occur during androgen‐induced regrowth of prostate tumors. Understanding the differences between testosterone and DHT in inducing androgen‐responsive genes during prostate tumor regrowth may provide new insight for improving IADT.

METHODS

Nude mice bearing androgen‐sensitive LNCaP xenograft were castrated and followed up for 7–10 days before being randomized into various androgen manipulations, consisting of continuous castration (C) or testosterone replacement (T) in the absence or presence of dutasteride (D), a 5α‐reductase inhibitor that blocks the conversion of testosterone to DHT. Testes‐intact animals in the absence or presence of D were used as controls. The expression of five androgen‐responsive genes, including the tumor suppressor U19/Eaf2, was determined using real‐time RT‐PCR, 3 days after randomization.

RESULTS

In LNCaP tumors, the expression of U19/Eaf2 was higher in the T+D group as compared with T alone (2.87‐fold, P < 0.05). In contrast, dutasteride treatment in testes‐intact animals inhibited the expression of U19/Eaf2.

CONCLUSIONS

Inhibition of 5α‐reductase during LNCaP tumor regrowth enhanced the expression of U19/Eaf2, an androgen‐regulated tumor suppressor. This finding suggests that off cycle 5α‐reductase inhibition may enhance the efficacy of IADT. Prostate 70: 1575–1585, 2010. © 2010 Wiley‐Liss, Inc.
Changes in caveolae, caveolin, and polymerase 1 and transcript release factor (PTRF) expression in prostate cancer progression
Authors: Gould M.L. , Williams G. , Nicholson H.D.
Published: June 2010

BACKGROUND

Caveolae are specialized invaginations in the cell membrane involved in the regulation of cell transport and signal transduction. The aims of this study were to investigate the number of caveolae and expression of caveolae‐associated proteins, caveolin‐1 and ‐2, and polymerase 1 and transcript release factor (PTRF) with development of prostate cancer.

METHODS

Transmission electron microscopy was used to investigate the number of caveolae in normal human prostate stromal, epithelial cells, and androgen‐dependent (LNCaP) and androgen‐independent (PC3) cancer cell lines. Surgical tissue was obtained from patients with benign prostatic hyperplasia (BPH), well‐differentiated and poorly differentiated prostate cancer. Caveolin‐1, caveolin‐2, and PTRF expression was identified by immunohistochemistry in tissue samples and quantified by Western blot analysis in cell lines.

RESULTS

Caveolae were identified in normal epithelial and stromal prostate cells. The number of caveolae was significantly reduced in LNCaP and PC3 cells (P < 0.0001). PTRF was localized to stromal and epithelial cells in tissue from patients with BPH and in normal stromal and epithelial cells in vitro. PTRF expression was significantly decreased in LNCaP and PC3 cells and also in cancer tissue. In prostate tissue, caveolin‐1 and ‐2 expression appeared to increase in prostate cancer. Caveolin‐1 and ‐2 expression was decreased in LNCaP cells but caveolin‐2 expression was significantly increased in PC3 cells compared to normal epithelial cells.

CONCLUSIONS

This study demonstrates that changes in the cell membrane involving loss of caveolae and PTRF expression occur with the development of prostate cancer. These changes are accompanied by an up‐regulation of caveolin‐2. Prostate 70: 1609–1621, 2010. © 2010 Wiley‐Liss, Inc.
Relationship between three polymorphisms of methylenetetrahydrofolate reductase (MTHFR C677T, A1298C, and G1793A) gene and risk of prostate cancer: A case–control study
Authors: Safarinejad Mohammad Reza , Shafiei Nayyer , Safarinejad Shiva
Published: June 2010

BACKGROUND

We hypothesized that genetic polymorphisms in methylenetetrahydrofolate reductase (MTHFR) gene are associated with prostate cancer risk.

METHODS

We genotyped three MTHFR polymorphisms (C677T, A1298C, and G1793A) and measured serum total homocysteine (tHcy), folate, and vitamin B12 levels in a case–control study of 174 cases and 348 normal healthy controls. The cancer‐free controls were frequency matched to the cases by age (±2 years), educational level, occupational status, ethnicity, and smoking status.

RESULTS

We found that the MTHFR 677TT and 1298CC genotypes were associated with an about 40% reduction in risk of prostate cancer (adjusted OR = 0.59, 95% CI = 0.41–0.94, and adjusted OR = 0.58, 95% CI = 0.32–0.91, respectively) compared to the 677CC, and 1298AA genotypes. The combined variant genotypes of 1298AC + 677CC were associated with a 30% reduction in risk of prostate cancer (OR = 0.70; 95% CI = 0.53–0.79). In contrast, the variant genotypes of 1793GA + 677CT were associated with slightly increased risk for prostate cancer (OR = 1.64; 95% CI = 0.86–2.15). Regarding prostate cancer aggressiveness, the 677TT genotype was associated with more than 50% decreased risk of high‐grade prostate cancer (Gleason score >7) compared with the 677CC and 677CT genotypes (OR = 0.35, 95% CI = 0.24–0.64; P = 0.001). There was no significant difference in plasma levels of tHcy, folate, and vitamin B12 between the two groups with any genotypes.

CONCLUSION

These data suggest that all three MTHFR polymorphisms may play a pivotal role in the developing prostate cancer. Larger studies in different ethnic populations and incorporating dietary folate intake are needed to replicate our findings. Prostate 70: 1645–1657, 2010. © 2010 Wiley‐Liss, Inc.
New prospective for non‐invasive detection, grading, size evaluation, and tumor location of prostate cancer
Authors: Cortesi M. , Fridman E. , Volkov A. , Shilstein S. Sh. , Chechik R. , Breskin A. , Vartsky D. , Raviv G. , Ramon J.
Published: June 2010

BACKGROUND

PSA blood test and other present screening tools fail to provide the required sensitivity and specificity and, at early stages, lack correlation with tumor grade, volume, and location. Thus alternative approaches are highly desired. We present and assess a novel method for PCa detection, grading, volume evaluation and tumor location, based on non‐invasive zinc concentration mapping in the gland by means of a dedicated rectal probe.

METHODS

Zinc‐concentration values measured in histologically examined tissue fragments from needle biopsy of 598 patients were analyzed. They were used to generate computer simulated zinc‐concentration maps, further analyzed with image‐processing tools. The tumor detection performances versus Gleason grade were assessed.

RESULTS

A significant increase of zinc depletion with increasing Gleason pattern (grade) classification was established. Tumor detection performance in zinc‐concentration maps progressively improves with the cancer's first component score. Reliable information on the location, size and Gleason‐grade combination of the lesion can be extracted for clinically relevant volumes.

CONCLUSIONS

Zinc depletion in the prostate peripheral zone is the basis for a novel, non‐invasive PCa detection, localization, volume evaluation and grading method. Its realization and application as a pre‐biopsy and pre‐treatment examination, or a follow‐up tool, relies on the development of a dedicated transrectal probe. It should have significant impact on biopsy effectiveness, point at a possible extraprostatic extension and provide critical data for focal treatment. The information on tumor grade and distribution may have an important impact on disease management. Prostate 70: 1701–1708, 2010. © 2010 Wiley‐Liss, Inc.
Gene expression correlation analysis predicts involvement of high‐ and low‐confidence risk genes in different stages of prostate carcinogenesis
Authors: Yano Kojiro
Published: June 2010

BACKGROUND

Whole genome association studies have identified many loci associated with the risk of prostate cancer (PC). However, very few of the genes associated with these loci have been related to specific processes of prostate carcinogenesis. Therefore I inferred biological functions associated with these risk genes using gene expression correlation analysis.

METHODS

PC risk genes reported in the literature were classified as having high (P < 10−6), medium (P < 10−4), or low (P < 10−2) statistical confidence. Correlation coefficients of the expression levels between the risk genes and other genes in cancerous prostates samples were compared against those in normal prostates using a microarray dataset from Gene Expression Omnibus.

RESULTS

Overall, significant decrease of correlations in PC was observed between the levels of expression of the high‐confidence genes and other genes in the microarray dataset, whereas correlation between low‐confidence genes and other genes in PC showed smaller decrease. Genes involved in developmental processes were significantly correlated with all risk gene categories. Ectoderm development genes, which may be related to squamous metaplasia, and genes enriched in fetal prostate stem cells (PSCs) showed strong association with the high‐confidence genes. The association between the PSC genes and the low‐confidence genes was weak, but genes related to neural system genes showed strong association with low‐confidence genes.

CONCLUSIONS

The high‐confidence risk genes may be associated with an early stage of prostate carcinogenesis, possibly involving PSCs and squamous metaplasia. The low‐confidence genes may be involved in a later stage of carcinogenesis. Prostate 70: 1746–1759, 2010. © 2010 Wiley‐Liss, Inc.
In silico analysis and DHPLC screening strategy identifies novel apoptotic gene targets of aberrant promoter hypermethylation in prostate cancer
Authors: Murphy Therese M. , Sullivan Linda , Lane Caroline , O'Connor Lisa , Barrett Ciara , Hollywood Donal , Lynch Thomas , Lawler Mark , Perry Antoinette S.
Published: June 2010

BACKGROUND

Aberrant DNA methylation has been implicated as a key survival mechanism in cancer, whereby promoter hypermethylation silences genes essential for many cellular processes including apoptosis. Limited data is available on the methylation profile of apoptotic genes in prostate cancer (CaP). The aim of this study was to profile methylation of apoptotic‐related genes in CaP using denaturing high performance liquid chromatography (DHPLC).

METHODS

Based on an in silico selection process, 13 genes were screened for methylation in CaP cell lines using DHPLC. Quantitative methylation specific PCR was employed to determine methylation levels in prostate tissue specimens (n = 135), representing tumor, histologically benign prostate, high‐grade prostatic intraepithelial neoplasia and benign prostatic hyperplasia. Gene expression was measured by QRT‐PCR in cell lines and tissue specimens.

RESULTS

The promoters ofBIK,BNIP3,cFLIP,TMS1,DCR1,DCR2, andCDKN2Aappeared fully or partially methylated in a number of malignant cell lines. This is the first report of aberrant methylation ofBIK,BNIP3, andcFLIPin CaP. Quantitative methylation analysis in prostate tissues identified 5 genes (BNIP3,CDKN2A,DCR1,DCR2andTMS1) which were frequently methylated in tumors but were unmethylated in 100% of benign tissues. Furthermore, 69% of tumors were methylated in at least one of the five‐gene panel. In the case of all genes, exceptBNIP3, promoter hypermethylation was associated with concurrent downregulation of gene expression.

CONCLUSION

Future examination of this “CaP apoptotic methylation signature” in a larger cohort of patients is justified to further evaluate its value as a diagnostic and prognostic marker. Prostate 71: 1–7, 2011. © 2010 Wiley‐Liss, Inc.
Safety and non‐safety data link technology characterization for NEWSKY aeronautical communication network
Authors: Leconte Katia , Díaz Núria Riera , Schrekenbach Frank , Platt Philip
Published: June 2010

A review and characterization of possible air/ground data link technologies for aeronautical cockpit and cabin communications is presented in this study. The study was performed in the framework of the EC project NEWSKY, which aims at defining an integrated network based on IPv6 protocol, supporting both cockpit and cabin communications over different data link sub‐networks. The objective of this study is to characterize the data link technologies that could be interfaced with such a network, either for safety (cockpit) or for non‐safety (cabin) communications and to define some high‐level categories gathering technologies with common characteristics. These categories were defined to enable the NEWSKY network to interface with a large range of data link technologies, both current and future. They describe typical characteristics for the sub‐networks data links for which the networking solutions are defined.

For this purpose, a thorough review of candidate technologies for cabin and cockpit applications was performed and is presented hereafter. It covers a large range of terrestrial (direct air–ground) or satellite solutions, with an emphasis on the satellite communication technologies that have more specific characteristics. Copyright © 2010 John Wiley & Sons, Ltd.
Cortisol variability and self‐reports in the measurement of work‐related stress
Authors: Karlson Björn , Eek Frida , Hansen Åse Marie , Garde Anne Helene , Ørbæk Palle
Published: June 2010

We examined whether a high cortisol awakening response (CAR) and low cortisol decline over the day (CDD) are related to self‐reported work stress and well‐being, and whether there are gender differences in these relationships. Three hundred eighty‐three working men and women responded to a survey measuring job stress factors, mastery at work, symptoms and well‐being. Salivary cortisol was sampled at awakening, after 45 min and at 21:00, from which the variables CAR and CDD were defined. A high CAR was associated with lower perceived job control and work mastery, and poorer well‐being. Low CDD was associated only with higher job demands, but the self‐report scores showed a number of interactions between cortisol group and gender. Among women, those showing a low CDD, compared with those with a higher CDD, had more favourable scores on a number of job stress factors and symptom load. In contrast, among men, a similar comparison showed those with low CDD to have poorer scores on job stress factors and symptom load. We conclude that individuals displaying high CAR or low CDD differ from those not displaying these cortisol profiles in self‐report of work stress and well‐being, and that gender differences appear in these relationships. Copyright © 2010 John Wiley & Sons, Ltd.
Modeling Study of the Vortex and Short Circuit Flow Effect on Inclusion Removal in a Slab Tundish
Authors: García‐Hernández S. , Barreto J. de J. , Ramos‐Banderas J. A. , Solorio‐Diaz G.
Published: June 2010

A mathematical model was developed to study effects of the vortex and the short circuit flow phenomena during tundish operation on the inclusion removal for a wide range of particle diameters. The model was solved using FLUENT® commercial software; for the particle tracking the Lagrangian discrete phase model was employed. Even when the vortexes drag about 50% of the inclusions, the most detrimental phenomenon for inclusion removal is the short circuit flow. It is important to stress that for the global inclusion behavior the removal rate decreases as the tundish level increases. It can be concluded that when increasing the tundish capacity without any flow control device adjustment, the steel cleanliness is deteriorated significantly.
Effect of Microstructure on Mechanical Properties of a Thin‐walled Cast Duplex Steel
Authors: Petzold L. , Minnich D. , Kreschel T. , Peisker D.
Published: June 2010

The paper investigates the microstructure and the resulting mechanical properties of a duplex steel cast in sand dead‐moulds. The chemical composition and the cooling rate are the main parameters affecting the properties. The chemical composition influences the thermodynamics of the phase transformation, the cooling rate determines the kinetics of formation of the microstructure. The latter varies with changes in wall thickness (investigated from 2 to 7 mm) and the position of the material within the casting. Through heat treatment, the composition of the microstructural components can be changed selectively afterwards, thereby the properties are improved. The correlation between microstructure and mechanical properties is explained quantitatively. Additionally to the austenite‐ferrite ratio, the dispersion of microstructure has a large influence on the mechanical properties. Ranges of chemical composition and heat treatment parameters are identified where third phases, such as carbides and σ‐phase tend to occur. These influence the properties very sensitively even in small amounts. Finally, structural parameters are recognized that will lead to optimal combinations of properties. With an appropriate heat treatment technique, in particular the ductility properties are further increased.
Transient Flow and Inclusion Removal in Gas Stirred Ladle during Teeming Process
Authors: Qu T. , Jiang M. , Liu C. , Komizo Y.
Published: June 2010

A water model of a typical 150t ladle was designed and constructed to determine the flow characteristics. A kind of organic emulsion was selected to model nonmetallic inclusion particles with the purpose of studying the inclusion removal effect under gas blowing in a teeming ladle. The presented modeling method for inclusion particles in the teeming process is different from those under steady condition. The numerical simulation was performed by using commercial software with the Eulerian‐Eulerian multiphase model applied to a model gas blown through a ladle. The numerical component of this study was conducted aiming at exploring the transient flow characteristics in teeming ladle corresponding to the physical experimental condition. Under the present conditions the authors came to the conclusion that soft gas blowing (2.7∼4.0 × 10−6 m3/s) was favourable to float inclusion particles into the slag layer. It is suggested to end the gas blowing when the drainage percentage reaches 50%.
Influence of Temperature Evolution on Precipitation Behaviour of Second Phase Particles in Grain‐oriented Electrical Steels
Authors: Mao W. , An Z. , Guo W. , Yang P.
Published: June 2010

A model concerning dynamic precipitation of second phase particles during hot deformation of conventional grain‐oriented electrical steels is proposed. The model involves the solid solubility of the elements forming MnS, the corresponding nucleation driving force, as well as the evolution of dislocation densities during hot deformation, which supplies sites for heterogeneous nucleation of MnS particles. The model describes the dynamic process in which temperature keeps decreasing and dislocation density keeps increasing. The influences of reheating temperature, initial rolling temperature, finishing temperature and deformation duration on the precipitation behaviour are involved. Calculations have been conducted based on the model, to simulate the precipitation behaviour of MnS particles during hot rolling of grain‐orientated electrical steels under different parameters. The results indicate that hot rolling is very important for dispersive precipitation of MnS particles. The increase of particle density is promoted by proper increase of reheating temperature or proper reduction of initial and finishing rolling temperature, in which the driving force and dislocation density are increased. The simulation results agree basically with the experimental observations in hot strip of a grain oriented electrical steel.