bluuebunny/crossref_metadata_2025 huggingface dataset:
Biodiesel from Oilseeds in the Canadian Prairies and Supply-Chain Models for Exploring Production Cost Scenarios: A Review
Authors: Newlands Nathaniel K. , Townley-Smith Lawrence
Published: May 2012

Canada recently implemented a federal mandate of 2% of renewable content in diesel fuel and heating oil. Federal-level biofuel strategy is currently more geared to bioethanol, as nonfood oils continue to be more cost-competitive and canola seeded area is forecast to increase 10% as a new record due to strong prices and high expected yields. Increasing focus is therefore being placed on alternative oilseeds as nonfood crops for biodiesel and their ability to adapt to the semiarid conditions of the Canadian Prairies and provide benefits in nutrient and water-use efficiency when introduced into the crop rotation. Systems engineering and supply-chain modeling and optimization will have an increasingly important role in decision making for designating supply units, the linkage of processes and chains, and biorefinery system design. However, current models require further enhancement to address current challenging questions: (1) changing spatial considerations (e.g., land use and suitability for feedstocks), (2) changing temporal dynamics of supply and risk of climate extreme impacts on transportation networks (road, rail, pipeline), price volatility, changes in policy targets and subsidy regimes, process technological change, and multigenerational biorefinery systems engineering advancements. Greater integration internationally in model development and testing would improve sensitivity and reliability in their system-level predictions and forecasts.
Separation of water–isopropyl alcohol mixtures with novel hybrid composite membranes
Authors: Saraswathi Mekala , Viswanath Buddolla
Published: May 2012

New‐fangled hybrid composite membranes were prepared by the incorporation of 5, 10, and 15 mass % NaY–zeolite particles into blend membranes of carboxymethyl cellulose (CMC)‐g‐acrylamide/sodium alginate (NaAlg) and crosslinked with glutaraldehyde. The pervaporation (PV) separation performance of the hybrid composite membranes was explored for the dehydration of isopropyl alcohol from their aqueous solutions at 30°C. The effect of NaY–zeolite in these blend membranes was investigated in PV dehydration. From the experimental results, we found that NaY particles could be intercalated in the aqueous polymer solution. The obtained results show that both the flux and selectivity increased simultaneously with increasing zeolite content in the membrane. This was explained on the basis of an enhancement of the hydrophilicity, selective adsorption, and molecular sieving action by the creation of pores in the membrane matrix. The membranes were characterized by differential scanning calorimetry, scanning electron microscopy, and Fourier transform infrared spectroscopy. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2012
An approach to assess the synergistic effect of natural antioxidants on the performance of the polypropylene stabilizing systems
Authors: Conde Enma , Castro López Mª del Mar , Moure Andrés , Manuel López Vilariño José , Domínguez Herminia , Abad López Mª José , González Rodríguez Victoria
Published: May 2012

A study on the efficiency of natural antioxidants from agri‐food industry wastes as long‐term antioxidants for polypropylene (PP) is reported. Special attention is paid to the usage of vegetal wastes as a source of natural antioxidants such as alternatives to synthetic long‐term antioxidants. The potential of the lignin‐derived fractions generated during autoydrolysis processing of lignocellulosic agricultural, forestal, and food wastes was assessed. The measurements of oxidation induction time were used for obtaining information on long‐term antioxidant effectiveness, showing the protective effect of natural extracts. The protective effect was improved in combinations of natural extracts with 0.1% and 0.2% of Irgafos 168 (short‐term antioxidant) besides a synergistic effect was exhibited when 0.4% of Irgafos 168 is added. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Fabrication and characterization of cypermethrin nanocapsules in miniemulsion polymerization system
Authors: Xia Chun‐Miao , Zhou Yi‐Feng , Nie Wang‐Yan , Song Lin‐Yong , Dai Ming‐Dong , Xu Xiao‐Ling , Wang Zhen
Published: May 2012

The nanoencapsulation of cypermethrin (CP) was carried out by miniemulsion polymerization, a convenient one‐pot encapsulation technique for nanocapsules. The encapsulation was achieved by polymerization inducing phase separation within minidroplets dispersed in an aqueous phase. For nanocapsules prepared in this way, the type of surfactant and initiator, the level of the crosslinking agent or chain‐transfer agent, and the monomer/CP ratio play a significant role in defining the end morphology of the latex particles. Specifically, for a styrene (St)/CP system, there were optimum levels of ionic surfactant (1.0 wt % sodium dodecyl sulfate), nonionic surfactant [0.5 wt % poly(ethylene glycol) monooctylphenyl ether], oil‐soluble initiator [1.0 wt % azobis(isobutyronitrile)], crosslinking agent (1.0 wt % divinylbenzene), and a St/CP ratio of 1 : 1 for obtaining well‐defined nanocapsules of CP. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Experimental and finite element modeling of vinyl ester nanocomposites under blast and quasi‐static flexural loading
Authors: Almagableh Ahmad , Raju Mantena P.
Published: May 2012

Materials used in blast, penetration, and impact loaded structural applications require high strength and toughness under high strain rate loading. 510A‐40 brominated bisphenol‐A‐based vinyl ester resin was developed and reinforced with different loadings of nanoclay and exfoliated graphite platelet to produce composites with optimal flexural rigidity, vibration damping, and enhanced energy absorption. As these reinforced polymeric materials are viscoelastic in principle, the mechanical behavior was characterized under two extremes of strain rate loading. In this article, the macroscopic response of brominated vinyl ester reinforced with 1.25 and 2.5 wt % nanoclay and exfoliated graphite platelet is considered. Air‐blast experiment was conducted by subjecting these specimens to a high‐transient pressure in a shock‐tube with flexural loading configuration. The axial response was investigated quasi‐statically in a uniaxial tension/compression test and dynamically in a compression Split‐Hopkinson bar test. The servo‐hydraulic MTS system was used to simulate the shock‐tube testing in a flexural quasi‐static loading configuration. High strain rate properties obtained from shock‐tube experiment are compared with that of characterized under the simulated quasi‐static flexural loading. Further, a computational finite element analysis model was developed in ANSYS LSDYNA to predict with reasonable accuracy the dynamic response of shock‐loaded nanoreinforced specimens. Drop in both failure strain and energy absorption was observed with the addition of nanoparticles to pristine vinyl ester. However, an improvement in energy absorption was observed in case of shock‐tube loading at high strain rates as compared to that loaded quasi‐statically. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci., 2012
Drawing and ultimate tenacity properties of polyamide 6/attapulgite composite fibers
Authors: Tsai Fang‐Chang , Li Peng , Liu Zhi‐Wei , Feng Gang , Zhu Ping , Wang Chuen‐Kai , Chen Kan‐Nan , Huang Chi‐Yuan , Yeh Jen‐taut
Published: May 2012

The drawing and ultimate tenacity properties of the Polyamide 6 (PA6)/Attapulgite (ATP) composite fiber specimens prepared at varying modified ATP (mATP) contents and drawing condition were systematically investigated. As evidenced by Fourier transform infrared (FTIR) and morphological analysis, demarcated translucent resins were found firmly attached on the surfaces of ATP nanofibers. The specific surface areas of the mATP specimens reached a maximum value at 381 m2/g as the weight ratios of silane coupling agents to ATP nanofibers reached an optimum value at 1.0. The percentage crystallinity and melt shear viscosity values measured at varying shear rates of PA6x(mATP)y specimens increased consistently as their mATP contents increased. In contrast, melting temperatures of PA6x(mATP)y specimens reduced slightly as their mATP contents increased. At a fixed drawing temperature and rate, the achievable draw ratio (Dra) values of PA6x(mATP)y as‐spun fiber specimens approach a maximum value, as their mATP contents are close to the 0.2 wt % optimum value. The maximum Dra values obtained for PA699.8(mATP)0.2 as‐spun fiber specimens reached another maximum, when their drawing temperatures and rates approached the optimum values at 120°C and 50 mm/min, respectively. At a fixed draw ratio, the tenacity values of PA6x(mATP)y drawn fiber specimens drawn at the optimum drawing temperature and rate reached a maximum value, as their mATP contents approached the 0.2 wt % optimum value. Possible reasons accounting for the interesting morphological, specific surface area, drawing, orientation, and ultimate tenacity properties found for the PA6x(mATP)y fiber specimens are proposed. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Polyoxymethylene/thermoplastic polyurethane blends compatibilized with multifunctional chain extender
Authors: Tang Weihua , Wang Huanhuan , Tang Jian , Yuan Huilin
Published: May 2012

Novel compatibilized polyoxymethylene/thermoplastic polyurethane (POM/TPU) blends are successfully developed using multifunctional chain extender, Joncryl ADR‐4368, as the compatibilizer. The outstanding compatibilization efficiency of Joncryl on POM/TPU blend was demonstrated by its even higher mechanical properties with only 0.5 wt % of Joncryl than those with 5 wt % of three commonly used compatibilizers. Addition of only 0.5 wt % Joncryl can double the impact strength and significantly improve its tensile strength and flexural strength for POM/TPU (75/25) blend. SEM images show that Joncryl can reduce TPU particle size and enhance the interfacial interactions between POM and TPU. The interparticle distance of TPU in POM/TPU/Joncryl blends was calculated as 0.2 μm, quite close to the critical matrix ligament thickness of POM/TPU blends (0.18 μm). The impact force profile vividly shows that the addition of Joncyl in POM/TPU blends can dramatically increase the total impact energy absorbed by this blend system and enhance the interfacial interactions between POM and TPU. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Electrochemical preparation and characterization of novel polyethylene/polyindene and polystyrene/polyindene composites
Authors: Talu Muzaffer , Uzluk Elif , Sarι Bekir , Selam Leyla
Published: May 2012

In this study, the conducting homopolymer of indene and polyethylene/polyindene (PE/PIn) and polystyrene/polyindene (PS/PIn) composites have been electrochemically synthesized on platinum electrode in nonaqueous acetonitrile. The physical, electrochemical, thermal, and spectral properties of the synthesized PIn and their composites were investigated. The conductivities of PIn and the composites were measured with a four‐probe technique. The conductivity of PIn was determined as 7.86 × 10−4 S/cm, whereas the conductivities of the PE/PIn and PS/PIn composites were determined to 6.42 × 10−5 S/cm and 5.64 × 10−5 S/cm, respectively. From Gouy scale magnetic susceptibility measurements, it was found that PIn and the composites had bipolaron natures. Fourier transform infrared spectra were taken to analyze the structural properties of PIn and the composites. The thermal properties of PIn and the PE/PIn and PS/PIn composites were investigated with thermogravimetric analysis, and it was found that they showed adequate thermal stability. According to the initial decomposition temperature among the composites, the composite including PE had the highest decomposition temperature with 450°C. The synthesized composites were different in aspect of morphology when compared to PIn. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Quantification of styrene–butadiene rubber swelling as a function of the toluene content in gasoline: A new method to detect adulterations of fuels
Authors: Takeshita Elaine V. , Piantola Felipe A. , de Souza Selene M. A. G. U. , Nunes Regina C. R. , de Souza Antônio A. U.
Published: May 2012

The swelling of styrene–butadiene rubber (SBR) when exposed to organic solvents was measured and mathematically correlated to the toluene concentration in a complex mixture such as gasoline. This relation enables inferences to be made regarding the composition and quality criteria of the fuel and represents a new method to detect adulterations. Changes in the mass and volume were measured by gravimetric and hydrostatic techniques. A simplex‐lattice experimental mixture design was carried out in mixtures with toluene, heptane, and type C gasoline (a blend of gasoline with ethanol) and the mass swelling was statically analyzed for 5 and 15 min of continuous immersion in the mixtures of the solvents. For the experimental design two cubic equations were obtained with a high value for R2‐ajusted (>0.98) at 25°C ± 1°C correlating mass swelling of SBR and the content of solvents. For both immersion times, the greatest and most important effect over the mass swelling was the content of toluene, with the mass variations increasing proportionally with toluene content in the gasoline. The analysis of variance applied to the mass swelling data verified that it is possible to obtain good mathematical equations to associate the rubber swelling with the solvent composition and concentration. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
The use of poly(amidoamine) dendrimer in modification of jute for improving dyeing properties of reactive dyes
Authors: Zolriasatein Ali Akbar , Yazdanshenas Mohammad Esmail , Khajavi Ramin , Rashidi Abosaeed , Najafi Farhood
Published: May 2012

In this study, the poly(amidoamine) (PAMAM) G‐2 dendrimer was applied to the jute yarn. Fourier transform infrared spectrophotometry (FTIR) of the dendrimer‐treated jute yarn indicated that all carbonyl groups of the jute fiber have reacted with amino groups of the PAMAM dendrimer. Jute yarns which had been pretreated with PAMAM dendrimer displayed markedly enhanced color strength with reactive dyes, even when dyeing had been carried out in the absence of electrolyte or alkali. Dendrimer‐treated jute yarn showed much better light‐fastness than that of untreated jute yarn. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Thermal decomposition kinetic and flame retardancy of CaCO3 filled recycled polyethylene terephthalate/recycled polypropylene blend
Authors: Thumsorn Supaphorn , Yamada Kazushi , Leong Yew Wei , Hamada Hiroyuki
Published: May 2012

The flammability and thermal decomposition kinetics of recycled polyethylene terephthalate (RPET)/recycled polypropylene (RPP) blends filled with CaCO3 were investigated. The thermal decomposition kinetics were determined by using various models such as the Flynn‐Wall‐Ozawa, Kissinger, and Kim‐Park, which would define the thermal stability of the blends through the determination of their decomposition activation energies. Meanwhile, the flammability of the materials was also determined through the limiting oxygen index (LOI) method. It was found that blends with higher RPP content or contain CaCO3 exhibited higher resistance to thermal degradation judging from their higher activation energies. Furthermore, it was found that the isoconversion kinetic of the Flynn‐Wall‐Ozawa model could provide a better estimation of the decomposition activation energy at each stage of degradation. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Preparation and properties of MWCNTs/poly(acrylonitrile‐ styrene‐butadiene)/epoxy hybrid composites
Authors: Jyotishkumar P , Abraham Eldho , George Sajeev Martin , Elias Eldho , Pionteck Jürgen , Moldenaers Paula , Thomas Sabu
Published: May 2012

Poly(acrylonitrile‐styrene‐butadiene) (ABS) was used to modify diglycidyl ether of bisphenol‐A (DGEBA) type epoxy resin, and the modified epoxy resin was used as the matrix for making multiwaled carbon tubes (MWCNTs) reinforced composites and were cured with diamino diphenyl sulfone (DDS) for better mechanical and thermal properties. The samples were characterized by using infrared spectroscopy, pressure volume temperature analyzer (PVT), thermogravimetric analyzer (TGA), dynamic mechanical analyzer (DMA), thermo mechanical analyzer (TMA), universal testing machine (UTM), and scanning electron microscopy (SEM). Infrared spectroscopy was employed to follow the curing progress in epoxy blend and hybrid composites by determining the decrease of the band intensity due to the epoxide groups. Thermal and dimensional stability was not much affected by the addition of MWCNTs. The hybrid composite induces a significant increase in both impact strength (45%) and fracture toughness (56%) of the epoxy matrix. Field emission scanning electron micrographs (FESEM) of fractured surfaces were examined to understand the toughening mechanism. FESEM micrographs reveal a synergetic effect of both ABS and MWCNTs on the toughness of brittle epoxy matrix. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Dynamic mechanical analysis of magnetic tapes at ultra‐low frequencies
Authors: Rummel Nicholas J. , Weick Brian L.
Published: May 2012

A custom, ultra‐low frequency, dynamic mechanical analyzer (ULDMA) has been developed to study the correlated effects of temperature and frequency on the viscoelastic behavior of magnetic tapes. It has been used to acquire data needed for the development of future magnetic tapes that require an archival life of up to 100 years. A range of elevated temperatures is used to simulate real‐world storage environments, which enables the investigation of how the viscoelastic characteristics of tape samples influence the extent to which the tape deforms. The experiments and subsequent analysis examine the influence of the molecular structure on the viscoelasticity of magnetic tapes. Experiments were performed on a variety of magnetic tapes, including poly(ethylene terephthalate) (PET), poly(ethylene naphthalate) (PEN), metalized PET (M‐PET), and metalized Spaltan (M‐SPA). Additional experiments examined PEN and PET substrates by removing the front and back magnetic layers from the tape sample. Because of the viscoelastic behavior of the tapes, a time delay was present between the strain and stress signals, which was determined using a Fourier transform program. The elastic modulus (E), storage modulus (E′), loss modulus (E″), and loss tangent (tan δ) were obtained from the time delay for each of the ULDMA experiments at 25, 50, and 70°C over the frequency range of 0.0100–0.0667 Hz. Plots of these mechanical characteristics demonstrate the ability of frequency and temperature to affect trends associated with mechanical and thermal properties. Finally, some samples displayed an initial relaxation during the ULDMA experiments, which, when modeled using Maxwell's viscoelastic model, provided an insight into the relaxation characteristics of the samples. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis and characterization of novel aromatic polyamides bearing CF3, quinoxaline‐anthraquinone pendants: Study of photophysical and electrochemical properties by using nanocomposite electrode paste
Authors: Ghaemy Mousa , Masoumi Arameh , Nasab Seyed Mojtaba Amini , Hassanzadeh Marjan
Published: May 2012

A new aromatic diamine, 2,3‐bis(4‐(4‐amino‐2‐(trifluoromethyl) phenoxy)phenyl)naphtho[2,3‐f]quinoxaline‐7,12‐dione, was synthesized and fully characterized by using FTIR, 1H and 13C NMR, DEPT technique, and elemental analysis. A series of novel fluorescent anthraquinone‐quinoxaline containing polyamides (PAs) with inherent viscosities of 0.39–0.62 dL/g was prepared by direct polycondensation of the diamine with various dicarboxylic acids. These PAs were readily soluble in many polar aprotic organic solvents and could be solution‐cast into tough and flexible films. The PAs exhibited glass transition temperatures (Tg)s between 230 and 323°C, and 10% weight loss temperatures in the range of 362–433°C in N2. All of the PAs have fluorescence emission in solution and in solid state with maxima around 452–510 nm and with the quantum yields in the range of 6–17%. Also, cyclic voltammetry (CV) method was used to study the electrochemical oxidation behavior of these polymers at the surface of a modified multiwalled carbon nanotube (MWCNT)s glassy electrode. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Preparation and properties of TiO2‐filled poly(acrylonitrile‐butadiene‐styrene)/epoxy hybrid composites
Authors: P Jyotishkumar , Pionteck Jürgen , Moldenaers Paula , Thomas Sabu
Published: May 2012

Poly (acrylonitrile‐butadiene‐styrene) (ABS) was used to modify diglycidyl ether of bisphenol‐A type of epoxy resin, and the modified epoxy resin was used as the matrix for making TiO2 reinforced nanocomposites and were cured with diaminodiphenyl sulfone for superior mechanical and thermal properties. The hybrid nanocomposites were characterized by using thermogravimetric analyzer (TGA), dynamic mechanical analyzer (DMA), universal testing machine (UTM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The bulk morphology was carefully analyzed by SEM and TEM and was supported by other techniques. DMA studies revealed that the DDS‐cured epoxy/ABS/TiO2 hybrid composites systems have two Tgs corresponding to epoxy and ABS rich phases and have better load bearing capacity with the addition of TiO2 particles. The addition of TiO2 induces a significant increase in tensile properties, impact strength, and fracture toughness with respect to neat blend matrix. Tensile toughness reveals a twofold increase with the addition of 0.7 wt % TiO2 filler in the blend matrix with respect to neat blend. SEM micrographs of fractured surfaces establish a synergetic effect of both ABS and TiO2 components in the epoxy matrix. The phenomenon such us cavitation, crack path deflection, crack pinning, ductile tearing of the thermoplastic, and local plastic deformation of the matrix with some minor agglomerates of TiO2 are observed. However, between these agglomerates, the particles are separated well and are distributed homogeneously within the polymer matrix. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Mechanism and kinetics of oxidation during the thermal stabilization of polyacrylonitrile fibers
Authors: Xiao Shijie , Cao Weiyu , Wang Bin , Xu Lianghua , Chen Biaohua
Published: May 2012

The thermal behavior and structural evolution during the thermal stabilization of polyacrylonitrile (PAN) fibers in N2 and air were investigated using differential scanning calorimetry and solid‐state 13C nuclear magnetic resonance. It was found that an oxidation reaction, that generated carbonyl (CO) groups could occur at 160°C which has not been reported in the literature. It is proposed that the cyclized structures in the PAN macromolecule chains are a prerequisite for the oxidation. Further investigations indicate that with more cyclized structures in the PAN macromolecule chains, the oxidation proceeds more readily, which is consistent with the proposed mechanism. The kinetic parameters for the oxidation and cyclization reactions were estimated using the Kissinger method. The activation energies for the reactions of oxidation and cyclization for PAN fibers are about 96.4 kJ/mol and 190.0 kJ/mol, respectively, which implies that the cyclization is the rate determining step during the thermal stabilization of PAN fibers. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis and characterization of poly(hydroxylic fluoroacrylate)/mSiO2 nanocomposite by in situ solution polymerization
Authors: Liu Hu , Fu Baosong , Shang Qianqian , Xiao Guomin
Published: May 2012

In this study, vinyl‐group modified nanosilicas (mSiO2) were prepared via sol–gel method using vinyltriethoxysilane (VTES) as modifier first, then the novel poly(hydroxylic fluoroacrylate)/mSiO2 nanocomposite was successfully synthesized by in situ solution polymerization of mSiO2 with dodecafluoroheptyl methacrylate (DFHMA), β‐hydroxyethyl methacrylate (HEMA), methyl methacrylate (MMA), and butyl acrylate (BA) initiated by 2,2‐azobisisobutyronitrile (AIBN) in the co‐solvents of ethyl acetate and butyl acetate. The chemical composition and structure of the nanocomposite were characterized by Fourier transform infrared spectrometry (FTIR) and transmission electron microscopy (TEM). TEM observation indicated that mSiO2 nanoparticles obtained a well dispersion in polymeric matrix. Thermogravimetric analysis (TGA) studies revealed that the temperature corresponding to 50% weight loss of the nanocomposite was improved by 21.5°C with the addition of 2.0 wt % mSiO2. The synthesized nanocomposites were applied to use with hexamethylene diisocyanate trimer (HDIT) to prepare polyurethane materials. Tensile test revealed that polyurethane material with mSiO2 content of 2.0 wt % showed an ultimate tensile strength of about 5.19 times higher than that without mSiO2. The polyurethane films displayed surface energy of lower than 25 mN m–1 and high light transmittance. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Dually stimuli‐responsive hyperbranched polyethylenimine with LCST transition based on hydrophilic–hydrophobic balance
Authors: Xia Yumin , Wang Jia , Xu Su , Liao Qian , Zhu Xinyuan , Wang Yanping , Wang Yimin
Published: May 2012

Dually stimuli‐responsive hyperbranched polyethylenimine derivatives (HPEI‐star‐PPOs) were successfully synthesized through Michael addition of commercial HPEI, poly(propylene oxide) dimethacrylate, and 2‐mercaptoethanol. In aqueous solution, these HPEI‐star‐PPOs exhibited response to temperature and pH. The corresponding lower critical solution temperature (LCST) could be readily adjusted by changing the feed ratio of HPEI to PPO, which also presents the ratio of hydrophilicity to hydrophobicity, indicating that this LCST transition is based on hydrophilic–hydrophobic balance. Because of the tertiary amine as well as unreacted primary or secondary amine that can be protonated during pH decreases, HPEI‐star‐PPOs exhibited a pH‐dependent thermoresponse. The 3‐(4,5‐dimethyl‐thiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide assay against COS‐7 cells demonstrated that HPEI‐star‐PPO had relatively low cytotoxicity compared to HPEI. All these characteristic suggest that this stimuli‐responsive polymer is a promising functional material for biomedical applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis and application of 2‐acrylamido‐2‐methyl propane sulfonic acid/acrylamide/N,N‐dimethyl acrylamide/maleic anhydride as a fluid loss control additive in oil well cementing
Authors: Guo Shenglai , Bu Yuhuan
Published: May 2012

Using 2‐acrylamido‐2‐methyl propane sulfonic acid (AMPS), acrylamide (AM), N,N‐dimethyl acrylamide (NNDMA), and maleic anhydride (MA), a new dispersive type fluid loss control additive (FLCA) AMPS/AM/NNDMA/MA (PANM) was synthesized by free radical aqueous solution copolymerization, and the new FLCA could be used without dispersant existing in the cement. The optimal PANM (OPANM) was obtained under the optimum reaction conditions: mole ratio of AMPS/AM/NNDMA/MA = 4/2.5/2.5/1, monomer concentration = 32.5%, amount of (by weight of monomer) ammonium persulfate/sodium bisulfate = 1.0%, pH value = 4, and temperature = 40°C. The synthesized copolymer OPANM was identified by FTIR analysis. The evaluation results show the OPANM has excellent dispersing power, fluid loss control ability, thermal resistant, and salt tolerant ability. The OPANM was even stable when the temperature was below 300°C proved by TG analysis. The thickening time of the slurry containing the synthesized additive reduces as the temperature increases. The copolymer OPANM is expected to be an excellent FLCA. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Transmission electron microscopic observations of the multilevel microstructure of crosslinked copolymers with methacrylates and siloxane macromers by a radically polymerizable tuning approach
Authors: Yokota Mitsuru , Ajiro Hiroharu , Akashi Mitsuru
Published: May 2012

We investigated by Transmission Electron Microscopy (TEM) the morphologies of crosslinked copolymers from methacrylate monomers from methylmethacrylate (MMA) and trifluoroethylmethacrylate (TFEMA), polydimethylsiloxane (PDMS) macromers with molecular weight (Mn) of 1,700 and 4,700 g/mol, and crosslinker. Depending on the PDMS content, we observed, spherical PMMA islands in which small PDMS domains were dispersed, PMMA continuous phase, closely packed PTFEMA islands, and homogeneously dispersed PDMS domains were observed with low or middle magnification. Fine observation at 100,000‐fold magnification revealed the “fundamental” common size domain, which was determined by the Mn value of the PDMS macromer. Thus we found two microstructure types: (1) a “fundamental domain” due to the Mn of the PDMS macromer, and (2) an aggregated domain. The former was constant under all conditions, but the latter was affected by the comonomer and its ratio. The present results are essential in understanding the chemical and physical characteristics of crosslinked copolymers from PDMS macromers. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Modification of polycarbonate by adding poly(L‐lactide)
Authors: Wang Yonghong , Shi Yunyun , Yang Jinghui , Huang Ting , Zhang Nan , Wang Yong
Published: May 2012

In this study, the blend of polycarbonate (PC)/poly(L‐lactide) (PLLA) (70/30) was prepared through the conventional extrusion‐injection‐molding process. The morphology of the blend was characterized using scanning electron microscope. Both differential scanning calorimetry and wide angle X‐ray diffraction were used to investigate the crystallization behavior of PLLA component in the blend. The mechanical and thermal properties of the blend were comparatively investigated, and the hydrolytic degradation ability of the material was also evaluated. The results show that the dispersed‐PLLA particles are in the amorphous state in the PC matrix. Although the blend is immiscible, the rigid PLLA particles exhibit the toughening and reinforcement effects on PC simultaneously. Specifically, the heat‐distortion temperature of the blend is comparable to that of pure PC. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Fluid catalytic cracking optimisation using factorial design and genetic algorithm techniques
Authors: Cuadros José F. , Melo Delba C. , Filho Rubens Maciel , Maciel Maria R. Wolf
Published: May 2012

Statistical techniques coupled with genetic algorithm (GA) were used to identify optimal values of key operational variables in fluid catalytic cracking (FCC) process. A Kellog Orthoflow F fluid catalytic cracking process model was considered. It is known as a highly nonlinear process with a large number of variables with strong interactions among them. A reduced process model was obtained through factorial design technique to be used as a process function in the optimisation work giving as result the operational conditions that maximise conversion without infringing operational restrictions with savings in computational burden and time. An increase of 8.71% in process conversion was achieved applying GA as optimisation technique. © 2012 Canadian Society for Chemical Engineering
Application of Chattim tree (devil tree, Alstonia scholaris) saw dust as a biosorbent for removal of hexavalent chromium from contaminated water
Authors: Saha Rumpa , Saha Indrajit , Nandi Rumki , Ghosh Aniruddha , Basu Ankita , Ghosh Sumanta K. , Saha Bidyut
Published: May 2012

“Devil tree saw dust”; a novel biosorbent has been utilised successfully for the removal of hexavalent chromium from contaminated water. Batch adsorption procedure is utilised to test the ability of saw dust as an adsorbent for hexavalent chromium (reduction coupled adsorption). The contribution of various parameters on sorption, such as contact time, sorbate concentration, pH of the medium and temperature were estimated and maximum uptake of hexavalent chromium from contaminated water was 333.33 mg g−1 at pH 2.0 and temperature of 35°C. Hexavalent chromium uptake from contaminated water followed the pseudo‐first‐order rate expression. The standard free energy change (ΔG0), standard enthalpy change (ΔH0) and standard entropy change (ΔS0) have also been evaluated and it has been concluded that the sorption was feasible, spontaneous and endothermic in nature. The process follows well Langmuir isotherm. Fourier Transform Infra‐Red (FTIR) spectroscopy and scanning electron microscopy (SEM) of hexavalent chromium loaded and unloaded saw dust were performed, SEM clearly indicates chromium adsorption. FTIR spectroscopy revealed the involvement of carbonyl, hydroxyl and amide groups on the cell surfaces in chromium binding. Very good adsorption capacity and low cost or cost free of devil tree saw dust makes this biosorbent as one of the best adsorbents for removal of hexavalent chromium from contaminated water. © 2012 Canadian Society for Chemical Engineering
Investigating the prevalence of complex fiber configurations in white matter tissue with diffusion magnetic resonance imaging
Authors: Jeurissen Ben , Leemans Alexander , Tournier Jacques‐Donald , Jones Derek K. , Sijbers Jan
Published: May 2012

It has long been recognized that the diffusion tensor model is inappropriate to characterize complex fiber architecture, causing tensor‐derived measures such as the primary eigenvector and fractional anisotropy to be unreliable or misleading in these regions. There is however still debate about the impact of this problem in practice. A recent study using a Bayesian automatic relevance detection (ARD) multicompartment model suggested that a third of white matter (WM) voxels contain crossing fibers, a value that, whilst already significant, is likely to be an underestimate. The aim of this study is to provide more robust estimates of the proportion of affected voxels, the number of fiber orientations within each WM voxel, and the impact on tensor‐derived analyses, using large, high‐quality diffusion‐weighted data sets, with reconstruction parameters optimized specifically for this task. Two reconstruction algorithms were used: constrained spherical deconvolution (CSD), and the ARD method used in the previous study. We estimate the proportion of WM voxels containing crossing fibers to be ∼90% (using CSD) and 63% (using ARD). Both these values are much higher than previously reported, strongly suggesting that the diffusion tensor model is inadequate in the vast majority of WM regions. This has serious implications for downstream processing applications that depend on this model, particularly tractography, and the interpretation of anisotropy and radial/axial diffusivity measures. Hum Brain Mapp 34:2747–2766, 2013. © 2012 Wiley Periodicals, Inc.
Mechanical flutter stimulation induces a lasting response in the sensorimotor cortex as revealed with BOLD fMRI
Authors: Christova Monica , Golaszewski Stefan , Ischebeck Anja , Kunz Alexander , Rafolt Dietmar , Nardone Raffaele , Gallasch Eugen
Published: May 2012

It has been recently shown that 20 min of mechanical flutter stimulation induces lasting motor cortical excitability changes, as assessed by transcranial magnetic stimulation in relaxed hand muscles. The present functional magnetic resonance imaging (fMRI) study aims to examine if such neuromodulatory changes are reflected in the BOLD signal during a motor test. Therefore, two groups were recruited: one group receiving whole‐hand flutter stimulation with a frequency of 25 Hz (FSTIM group, n = 22) and a second group receiving no stimulation (NOSTIM group, n = 22). As motor test finger‐to‐thumb tapping was performed to activate a wide sensorimotor network during the fMRI measurements. Three fMRI measurements were obtained with this test: before stimulation (PRE), after stimulation (POST1), and 1 h after stimulation (POST2). Three regions of interest (ROIs) were defined: primary motor area (M1), primary somatosensory area (S1), and supplementary motor area. In the absence of baseline differences between both groups, the FSTIM group showed increased movement‐related brain activations compared with the NOSTIM group, both at POST1 and POST2. ROI analysis revealed increased blood‐oxygenation‐level‐dependent (BOLD) responses within contralateral S1 (+20%) and M1 (+25%) at POST1, which lasted until POST2. These poststimulatory effects within S1 and M1 obviously reflect neuroplastic changes associated with augmented cortical excitability. These findings are of high clinical relevance, for example, to improve the treatment of stroke patients. Hum Brain Mapp 34:2767–2774, 2013. © 2012 Wiley Periodicals, Inc.
Dioxins: diagnostic and prognostic challenges arising from complex mechanisms
Authors: Rysavy Noel M. , Maaetoft‐Udsen Kristina , Turner Helen
Published: May 2012

Dioxins are ubiquitous environmental challenges to humans, with a pervasiveness that arises from 200 years of rapid industrialization and mechanization of Western societies and which is now extending into the developing world. In spite of their penetrance of the human biota, these compounds are poorly understood in terms of their true physiological potential for harm, and the mechanisms by which they impact cellular and organ level function are only recently becoming clear. Emerging awareness that chronic exposures to toxins may have generational and subtle effects on the outcomes of diseases such as cancer and diabetes, which are already multifactorial and highly complex, creates the context for the current review paper. Here, we summarize dioxin exposure paradigms and the resulting physiological effects that have been documented in animals and humans. Novel insights into potential endogenous end exogenous ligands, as well as the mechanisms by which these ligands impact acute and chronic cellular processes, are discussed. We develop the idea that the diagnosis of dioxin exposure, the subtleties of the cellular effects of the compounds and prognosis of the long‐term effects of exposure are problems requiring that researchers leverage the power of genomics and epigenetics. However, the continuation of longitudinal epidemiological studies and the development of a firmer basis from which to extrapolate animal studies will be critical in ensuring optimal insight from these resource‐intensive techniques. Copyright © 2012 John Wiley & Sons, Ltd.
A Pilot Study of Attention Bias Subtypes: Examining Their Relation to Cognitive Bias and Their Change following Cognitive Behavioral Therapy
Authors: Calamaras Martha R. , Tone Erin B. , Anderson Page L.
Published: May 2012

Objective

The present investigation examined (a) whether a clinical sample of individuals with social anxiety disorder (SAD) comprises two distinct groups based on attention bias for social threat (vigilant, avoidant), (b) the relation between attention bias and cognitive bias, specifically estimates of the probability that negative social events will occur (probability bias), and (c) specific changes in attention bias following cognitive behavioral therapy for social anxiety.

Method

Participants were 24 individuals (nfemale = 7, nmale = 17; mage = 41) who met diagnostic criteria for SAD and sought treatment for fear of public speaking. Hypotheses were tested using t tests, linear regression analyses, and a mixed design analysis of variance.

Results

Results yielded evidence of 2 pretreatment groups (vigilant and avoidant). There was a significant positive correlation between vigilance for (but not avoidance of) threat and probability bias (R = .561, p < .05). After 8 weeks of treatment, the direction of change in attention bias differed between groups, such that the vigilant group became less vigilant and the avoidant group became less avoidant, with the avoidant group showing a significant change in attention bias from pretreatment to posttreatment.

Conclusions

These findings provide very preliminary support for the idea that individuals with SAD may differ according to type attention bias, avoidant or vigilant, as these biases changed in different ways following cognitive‐behavioral therapy for SAD. Further research is needed to replicate and extend these findings in order to evaluate whether SAD comprises subgroups of attentional biases. © 2012 Wiley Periodicals, Inc. J. Clin. Psychol. 68:745‐754, 2012
Contrast‐enhanced sonography in the diagnosis of hepatic hemangiomas: Atypical appearance due to the washout of microbubbles
Authors: Giannetti Andrea , Franci Luca , Grechi Cristina , Giangregorio Francesco
Published: May 2012

Contrast‐enhanced sonography (CEUS) examination permits identification of hemangioma of the liver in most cases. This method is particularly useful when the ultrasound pattern is atypical on standard grayscale examination. CEUS appearances suggestive of hemangioma are peripheral globular enhancement, progression of enhancement toward the center of the nodule, and persistence of enhancement in the late phase. We present seven cases of hemangioma, which were atypical on CEUS examination due to washout during the portal and late phases, resulting in a hypoenhanced appearance compared with the adjacent liver parenchyma. © 2012 Wiley Periodicals, Inc. J Clin Ultrasound 41:361–365, 2013
Cancer therapy with genetically‐modified T cells for the treatment of melanoma
Authors: Lagisetty Kiran H. , Morgan Richard A.
Published: May 2012

The aim of this review is to acquaint the reader with the concept of T cell receptor (TCR) gene therapy for metastatic melanoma. We first review antigen choice, followed by gene delivery technology and, finally, we discuss selected clinical applications. To be successful, TCR gene therapy must combine multiple elements and research disciplines. First, there is a need for an understanding of tumor immunology because this is essential in proper antigen choice. Second, gene therapy is a technology‐driven field and cutting edge knowledge of protein engineering and gene delivery methods are indispensable. Finally, a dedicated team of physician/scientists and healthcare providers is fundamental to clinical success. TCR gene therapy is now a realistic treatment option for metastatic melanoma. Both tumor regression and on‐target/off‐tumor toxicities have been observed, which emphasizes the experimental nature of this approach. As with any new medical procedure, future large‐scale randomized trials will be necessary to validate this approach, and these are within reason in the next few years. This article is a US Government work and is in the public domain in the USA.
A functional trinucleotide repeat polymorphism in the 5′‐untranslated region of the glutathione biosynthetic gene GCLC is associated with increased risk for lung and aerodigestive tract cancers
Authors: Nichenametla Sailendra N. , Muscat Joshua E. , Liao Jason G. , Lazarus Philip , Richie John P.
Published: May 2012

Glutathione (GSH), the major intracellular antioxidant, protects against cancer development by detoxifying carcinogens and free radicals and strengthening the immune system. Recently, a GAG‐trinucleotide repeat polymorphism in the 5′‐untranslated region of the gene for the rate‐limiting enzyme for GSH biosynthesis, γ‐glutamine cysteine ligase (GCL), was shown to be associated with lowered GCL activity and GSH levels in vitro and in vivo. We tested the hypothesis that this functional polymorphism in GCL is associated with the risk for lung and aerodigestive tract cancers. To this end, we conducted a case–control study that included 375 lung cancer cases, 200 aerodigestive tract cancer cases, and 537 controls. GAG repeat genotype (4, 7, 8, 9, and 10 repeat alleles) was determined by capillary electrophoresis of PCR products from the repeat region of the GCL catalytic subunit (GCLC). Odds ratios (OR) were calculated by logistic regression and adjusted for risk factors, including age, sex, body mass index, and smoking history. The GAG‐7/7 genotype was associated with a 1.9‐fold increased risk of lung cancer and 2.6‐fold increased risk of aerodigestive tract cancer compared to the wild‐type GAG‐9/9 (P < 0.05). Similarly, the GAG‐7 allele was associated with an increased risk of lung cancer (OR = 1.5, P = 0.01) and aerodigestive tract cancer (OR = 2.3, P < 0.001) compared to subjects without GAG‐7 allele. These findings suggest that GSH synthesis affects the risk of lung and aerodigestive tract cancers, and further implicates a role for oxidative stress in the development of these cancers. © 2012 Wiley Periodicals, Inc.
A branch‐and‐bound algorithm for the double travelling salesman problem with two stacks
Authors: Carrabs Francesco , Cerulli Raffaele , Speranza Maria Grazia
Published: May 2012

This article studies the double traveling salesman problem with two stacks. A number of requests have to be served where each request consists in the pickup and delivery of an item. All the pickup operations have to be performed before any delivery can take place. A single vehicle is available that starts from a depot, performs all the pickup operations and returns to the depot. Then, it performs all the delivery operations and returns to the depot. The items are loaded in two stacks, each served independently from the other with a last‐in‐first‐out policy. The objective is the minimization of the total cost of the pickup and delivery tours. We propose a branch‐and‐bound approach to solve the problem. The algorithm uses properties of the problem both to tighten the lower bounds and to avoid the exploration of redundant subtrees. Computational results performed on benchmark instances reveal that the algorithm outperforms the other exact approaches for this problem. © 2012 Wiley Periodicals, Inc. NETWORKS, 2013
Balancing profits and costs on trees
Authors: Coene Sofie , Filippi Carlo , Spieksma Frits C. R. , Stevanato Elisa
Published: May 2012

We consider a rooted tree graph with costs associated with the edges and profits associated with the vertices. Every subtree containing the root incurs the sum of the costs of its edges, and collects the sum of the profits of its nodes; the goal is the simultaneous minimization of the total cost and maximization of the total profit. This problem is related to the TSP with profits on graphs with a tree metric. We analyze the problem from a biobjective point of view. We show that finding all extreme supported efficient points can be done in polynomial time. The problem of finding all efficient points, however, is harder; we propose a practical FPTAS for solving this problem. Some special cases are considered where the particular profit/cost structure or graph topology allows the efficient points to be found in polynomial time. Our results can be extended to more general graphs with distance matrices satisfying the Kalmanson conditions. © 2012 Wiley Periodicals, Inc. NETWORKS, 2013
Language Objectives: More Than Just Vocabulary
Authors: Regalla Michele
Published: May 2012

This article presents results of a study examining the effects of workshops presented to a small group of elementary student teaching interns with English learners mainstreamed in their classes. The focus of the workshops was to provide the interns with training in strategies to support their English learners including instruction on teaching language objectives according to the SIOP model. Results show that the interns' teaching of language objectives was limited to teaching vocabulary by creating context and using visual supports. Discussion suggests that although the teaching of key vocabulary is an important component of the SIOP model, language objectives cannot be limited to teaching word meaning. Teachers who are not trained to think linguistically may not be able to design language objectives beyond vocabulary. In order for teachers to take full advantage of the strategies presented in the SIOP model, they must be trained to think linguistically and to see themselves as experts of the language of their content.