bluuebunny/crossref_metadata_2025_split huggingface dataset:
Raman scattering on nanomaterials and nanostructures
Authors: Popović Z.V. , Dohčević‐Mitrović Z. , Šćepanović M. , Grujić‐Brojčin M. , Aškrabić S. 
Published: October 2010

AbstractThe conventional Raman scattering spectroscopy is one of the most used and powerful techniques for characterization of nano‐sized materials and structures. By proper analysis of optical mode shift and broadening in nanomaterials based on phonon confinement model, it is possible to deduce about the influence of various effects like particle size and size distribution, strain, change of phonon dispersion, substitutional effects, defect states and nonstoichiometry, electron‐phonon coupling. We have demonstrated potentials of this technique in CeO2 and TiO2 nanocrystalline systems analyzing their optical phonon properties.
The quantum Boltzmann equation in semiconductor physics
Authors: Snoke D.W. 
Published: October 2010

AbstractThe quantum Boltzmann equation, or Fokker‐Planck equation, has been used to successfully explain a number of experiments in semiconductor optics in the past two decades. This paper reviews some of the developments of this work, including models of excitons in bulk materials, electron–hole plasmas, and polariton gases.
MgCl2‐supported catalyst containing mixed internal donors for propylene polymerization
Authors: Gao Futang , Xia Xianzhi , Mao Bingquan 
Published: October 2010

AbstractA MgCl2‐supported catalyst containing diisobutyl phthalate (DIBP) and 2,4‐pentadiol dibenzoate (PDDB) as internal donors was prepared. Propylene polymerizations were carried out using the catalyst in the absence or presence of an external donor. The resulting polymers were characterized by 13C‐NMR, crystallization analysis fraction (CRYSTAF) and gel permeation chromatography (GPC). The performance of the catalyst was compared with that of other catalysts containing donor‐free, DIBP and PDDB as internal donors respectively. The results demonstrated that the catalyst containing mixed internal donors not only had high activity and stereospecificity but also produced the polymer with relatively broad molecular weight distribution and the highest [mmmm] value. 13C‐NMR analysis results indicated that strongly coordinating donors gave more stereoregular polymers, which was further confirmed by CRYSTAF data. The effects of mixed internal donors on the catalyst properties were discussed systematically. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Architecture of colloidal crystals constructed by silica hybrid nanoparticles
Authors: Ishizu Koji , Tokuno Yoko , Lee Dong Hoon , Uchida Satoshi , Ozawa Masaaki 
Published: October 2010

AbstractSilica (SiO2)‐crosslinked polystyrene (PS) particles possessing photofunctional N,N‐diethyldithiocarbamate (DC) groups on their surface were prepared by the free‐radical emulsion copolymerization of a mixture of SiO2 (diameter Dn = 192 nm), styrene, divinyl benzene, 4‐vinylbenzyl N,N‐diethyldithiocarbamate (VBDC), and 2‐hydroxyethyl methacrylate with a radical initiator under UV irradiation. In this copolymerization, the inimer VBDC had the formation of a hyperbranched structure by a living radical mechanism. These particles had DC groups on their surface. Subsequently, poly(methyl methacrylate) brushes encapsulated SiO2 particles were synthesized by the grafting from a photoinduced atom transfer radical polymerization (ATRP) approach of methyl methacrylate initiated by SiO2‐crosslinked PS particles as a macroinitiator. We constructed the colloidal crystals using these photofunctional particles. Moreover, the SiO2 particle array of colloidal crystals was locked by radical photopolymerization with vinyl monomer as a matrix. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Influence of the reactive processing of recycled poly(ethylene terephthalate)/poly(ethylene‐co‐glycidyl methacrylate) blends
Authors: Kunimune Noriaki , Yamada Kazushi , Leong Yew Wei , Thumsorn Supaphorn , Hamada Hiroyuki 
Published: October 2010

AbstractThe effect of the amount of reactive additive and screw speed during extrusion on the morphological characteristics and mechanical performance of recycled poly(ethylene terephthalate)(RPET) was investigated. With an increase in the ethylene–glycidyl methacrylate copolymer (E–GMA) additive content, a gradual increase in the Izod impact strength of the RPET/E–GMA blends was initially recorded. Subsequent increases in the E–GMA content to above 13.5 wt % led to a drastic enhancement in the toughness of the blends. Meanwhile, the density of the blends decreased with increasing amount of the additive E–GMA. The toughness and density of the blends were found to be dependent on the screw rotation speed during the extrusion. In addition, ductile and microporous structures were observed on the Izod impact fracture surfaces. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis and curing properties of a novel curing agent based on N‐(4‐hydroxyphenyl) maleimide and dicyclopentadiene moieties
Authors: Liu Jia , Zeng Xiao‐Liang , Zhang Xu‐Yong , Xia Xin‐Nian 
Published: October 2010

AbstractA new type of epoxy resin curing agent, containing pendant phenol functions, was synthesized by the free‐radical copolymerization of N‐(4‐hydroxyphenyl) maleimide with dicyclopentadiene (DCPD) monomer in the presence of a radical initiator. The chemical structure was characterized with Fourier transform infrared spectroscopy and nuclear magnetic resonance. The molecular weight of the new curing agent was determined by gel permeation chromatography. The activity and activation energy of this new curing agent with o‐cresol formaldehyde novolac epoxy (CNE) was investigated with a nonisothermal differential scanning calorimetry technique at different heating rates. The thermal properties of the cured polymers were evaluated with thermogravimetric analysis, and the results exhibit good thermal stability. In addition, this new curing agent with CNE showed low moisture absorption because of the hydrophobic nature of the DCPD structure. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Cure kinetics of a glass/epoxy prepreg by dynamic differential scanning calorimetry
Authors: Hayaty Mehran , Beheshty Mohammad Hosain , Esfandeh Masoud 
Published: October 2010

AbstractDicyandiamide (DICY)‐cured epoxy resins are important materials for structural adhesives and matrix resins for fiber‐reinforced prepregs. Dynamic differential scanning calorimetry (DSC) with heating rates of 2.5, 5, 10, and 15°C/min was used to study the curing behavior of the epoxy prepreg Hexply 1454 system, which consisted of diglycidyl ether of bisphenol A, DICY, and Urone reinforced by glass fibers. The curing kinetic parameters were determined with three different methods and compared. These were the Kissinger, Ozawa, and Borchardt–Daniels kinetic approaches. The lowest activation energy (76.8 kJ/mol) was obtained with the Kissinger method, whereas the highest value (87.9 kJ/mol) was obtained with the Borchardt–Daniels approach. The average pre‐exponential factor varied from 0.0947 × 109 to 2.60 × 109 s−1. The orders of the cure reaction changed little with the heating rate, so the effect of the heating rate on the reaction order was not significant. It was interesting that the overall reaction order obtained from all three methods was nearly constant (≅2.4). There was good agreement between all of the methods with the experimental data. However, the best agreement with the experimental data was seen with the Ozawa kinetic parameters, and the most deviation was seen with the Borchardt kinetic parameters. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Ionic salt permeability through phase‐separated membranes composed of amphoteric polymers
Authors: Ito Eri , Higuchi Masahiro , Yamamoto Katsuhiro , Nagata Kenji , Kinoshita Takatoshi 
Published: October 2010

AbstractAmphoteric copolymers composed of hydrophilic poly(dimethyl acrylamide) and hydrophobic poly(dimethyl siloxane) formed phase‐separated membranes. The hydrophilic and hydrophobic components formed continuous phase‐separated domains in the membranes. The hydrated poly(dimethyl acrylamide) domains formed membrane‐spanning pathways, which permitted an ionic salt to permeate the membranes. The permeability of the ionic salt through the amphoteric copolymer membranes was studied. On the basis of the results, the mechanism of salt transport could be explained by the free‐volume theory, which was used for the analysis of diffusive transport in the hydrated, homogeneous membranes. The diffusion coefficient of the ionic salt increased exponentially as the volume ratio of the hydrophilic polymer to water [(1 − H)/H, where H is the degree of hydration] decreased in the membrane. It was possible to postulate that the diffusion of the ionic salt through the membranes was dependent on the free‐volume fractions of water and hydrophilic poly(dimethyl acrylamide) domains in the membranes. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effect of repetitive processing on the mechanical properties and fracture toughness of dynamically vulcanized iPP/EPDM blends
Authors: Wang Wei‐Kang , Yang Wei , Bao Rui‐Ying , Xie Bang‐Hu , Yang Ming‐Bo 
Published: October 2010

AbstractThe effect of repetitive processing on the mechanical properties and fracture toughness of dynamically vulcanized isotactic polypropylene/ethylene‐propylene‐diene rubber blends (TPVs) with and without addition of β‐nucleating agent (β‐NA) was studied. The results showed that the repetitive processing did not cause much loss in the mechanical properties of TPVs, especially for TPVs with β‐NA, and TPVs with β‐NA showed better performance stability than TPVs without β‐NA. Essential work of fracture (EWF) approach was used to study the fracture behavior, and the results showed that the value of we (the specific essential work of fracture) of TPVs without β‐NA showed a significant decrease while that of TPVs with β‐NA almost kept constant after repetitive processing. Differential scanning calorimetry and wide‐angle X‐ray diffraction were used to study the variation of crystalline structures, and the results indicated that the repetitive processing showed no significant influence on the crystalline structures of TPVs, and the β‐NA maintained high‐nucleating efficiency after repetitive processing. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of the viscosity and processing parameters on the surface resistivity of polypropylene/multiwalled carbon nanotube and ethylene–propylene–diene/multiwalled carbon nanotube nanocomposites
Authors: Min Kyoung‐Tae , Kim Gue‐Hyun 
Published: October 2010

AbstractIn this study, relatively large amounts of polypropylene (PP) and ethylene–propylene–diene (EPDM) were melt‐mixed with multiwalled carbon nanotubes (MWCNTs). Although the melt‐compounding method has many advantages, the uniform dispersion of carbon nanotubes in the polymer matrix is still the most challenging task. Because the electrical conductivity of composites is strongly influenced by the filler's state of dispersion and the extent of filler breakage during processing, the effects of the viscosity and processing conditions, such as the mixing time, rotor speed, and cooling rate, on the surface resistivity were studied. The PP/MWCNT nanocomposites displayed a high dependence of surface resistivity on the cooling rate, and the EPDM/MWCNT nanocomposites displayed a higher surface resistivity at the same content of MWCNTs and less dependence of surface resistivity on the cooling rate compared with PP/MWCNT nanocomposites. The increased surface resistivity of the EPDM/MWCNT nanocomposites was observed when EPDM with higher viscosity was used to prepare the EPDM/MWCNT nanocomposites. By increasing the rotor speed, lower surface resistivity was obtained in the PP/MWCNT nanocomposites. However, by increasing the rotor speed, a higher surface resistivity was obtained in the EPDM/MWCNT nanocomposites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Control of molecular weight distribution for polypropylene obtained by a commercial Ziegler–Natta catalyst: Effect of a cocatalyst and hydrogen
Authors: Zhang He‐Xin , Lee Young‐Joo , Park Joon‐Ryeo , Lee Dong‐Ho , Yoon Keun‐Byoung 
Published: October 2010

AbstractThe polymerization of propylene was carried out with an MgCl2‐supported TiCl4 catalyst (with diisobutyl phthalate as an internal donor) in the absence and presence of hydrogen (H2) as a chain‐transfer agent. Different structures of alkylaluminum were used as cocatalysts. The effects of the alkyl group size of the cocatalyst, H2 feed, and feed time on the propylene polymerization behaviors were investigated. The catalyst activity significantly decreased with increasing alkyl group size in the cocatalyst. The molecular weight and polydispersity index (PDI) increased with increasing alkyl group size. With the introduction of H2, the catalyst activity increased significantly, whereas the molecular weight and PDI of polypropylene (PP) decreased. Additionally, the effect of the polymerization time in the presence of H2 on the propylene polymerization was studied. The molecular weight distribution curve was bimodal at short polymerization times in the presence of H2, and we could control the molecular weight distribution of PP by changing the polymerization time in the presence of H2. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Aerobic oxidative polymerization of 2,6‐dimethylphenol in water with a highly efficient copper(II)– poly(N‐vinylimidazole) complex catalyst
Authors: Zhang Wenli , Wang Huan , Shentu Baoqing , Gu Cheng , Weng Zhixue 
Published: October 2010

AbstractA Cu(II)–poly(N‐vinylimidazole) (PVI) complex was prepared and used to catalyze the oxidative polymerization of 2,6‐dimethylphenol (DMP) to form poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) in water. The stoichiometric ratio between imidazole groups in PVI and copper ions was found to be 4 when continuous variation analysis was applied. Compared with a conventional Cu(II)–low‐molecular‐weight ligand complex, a high catalytic efficiency was observed in the polymerization of DMP catalyzed by the Cu(II)–PVI complex. The influence of the Cu(II)–PVI complex concentration and imidazole/Cu(II) molar ratio on the oxidative polymerization of DMP was studied. Both the yield and molecular weight of PPO increased significantly with the catalyst concentration and decreased with the imidazole/Cu(II) molar ratio. The molecular weight of PVI also played an important role in the improvement of the catalytic efficiency. The high catalytic efficiency of the Cu(II)–PVI complex may have been due to the concentration effect of the catalyst and substrate. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Polymerization of epoxidized soybean oil with maleinized polybutadiene
Authors: Öztürk Cem , Küsefoğlu Selim H. 
Published: October 2010

AbstractEpoxidized soybean oil (ESO) triglycerides were reacted with maleinized polybutadiene (MMPBD) to give plant‐oil‐based thermoset polymers. MMPBD samples were of two different molecular weights [high‐molecular‐weight maleinized polybutadiene (MMPBD‐H), maleate content = 10%, number‐average molecular weight (Mn) = 9000, and low‐molecular‐weight maleinized polybutadiene (MMPBD‐L), maleate content = 15%, Mn = 5000]. To increase the crosslink density of the product, a free‐radical initiator, benzoyl peroxide, was added to this mixture to further crosslink MMPBD through its double bonds. The characterizations of the products were done by dynamic mechanical analysis, differential scanning calorimetry, thermogravimetric analysis, and IR spectroscopy. The ESO–MMPBD polymers were crosslinked rigid infusible polymers. ESO–MMPBD‐H–1 : 1 and ESO–MMPBD‐L–1 : 1 showed glass‐transition temperature values at −23, 78 and −17, 64°C, respectively, whereas the storage moduli of the two polymers at 25°C were 13 and 16 MPa, respectively. The storage moduli of the polymers remained the same or decreased with the addition of a free‐radical initiator. The storage moduli also decreased with increasing ESO concentration above a 1 : 1 epoxy‐to‐anhydride molar ratio. The surface hardness increased dramatically, and the equilibrium swelling ratio decreased with the addition of free‐radical initiator. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
New hybrid system: Poly(ethylene glycol) hydrogel with covalently bonded pegylated nanotubes
Authors: Saez‐Martinez Virginia , Garcia‐Gallastegui Ainara , Vera Carolina , Olalde Beatriz , Madarieta Iratxe , Obieta Isabel , Garagorri Nerea 
Published: October 2010

AbstractHydrogels containing carbon nanotubes (CNTs) are expected to be promising conjugates because they might show a synergic combination of properties from both materials. Most of the hybrid materials containing CNTs only entrap them physically, and the covalent attachment has not been properly addressed yet. In this study, single‐walled carbon nanotubes (SWNTs) were successfully incorporated into a poly(ethylene glycol) (PEG) hydrogel by covalent bonds to form a hybrid material. For this purpose, SWNTs were functionalized with poly(ethylene glycol) methacrylate (PEGMA) to obtain water‐soluble pegylated SWNTs (SWNT–PEGMA). These functionalized SWNTs were covalently bonded through their PEG moieties to a PEG hydrogel. The hybrid network was obtained from the crosslinking reaction of poly(ethylene glycol) diacrylate prepolymer and the SWNT–PEGMA by dual photo‐UV and thermal initiations. The mechanical and swelling properties of the new hybrid material were studied. In addition, the material and lixiviates were analyzed to elucidate any kind of SWNT release and to evaluate a possible in vitro cytotoxic effect. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Suitability of different salmonid strains as hosts for the endangered freshwater pearl mussel (Margaritifera margaritifera L.)
Authors: Taeubert Jens‐Eike , Denic Marco , Gum Bernhard , Lange Michael , Geist Juergen 
Published: October 2010

Abstract
The complex life cycle of endangered European freshwater pearl mussel Margaritifera margaritifera L. involves an obligatory parasitic phase on a host fish. Knowledge on the host–parasite interaction and on the suitability of different host fish species and strains is required both for the management of wild fish and mussel populations as well as for improving the efficiency of captive breeding methods.
In this study, the suitability of different salmonid strains for hosting glochidia was tested, including Danube salmon (Hucho hucho L.) and three brown trout (Salmo trutta L.) strains from inside and outside the freshwater pearl mussel distribution range. All brown trout strains as well as Danube salmon were successfully infected with freshwater pearl mussel glochidia and encystment of mussel larvae was detected.
One brown trout strain originating from the natural pearl mussel distribution range was identified as the most suitable host, revealing the highest fish‐weight‐normalized infection rates and highest glochidial growth rates, whereas endemic Danube salmon was least suitable. Under natural conditions, the role of Danube salmon may be attributed to the long‐distance dispersal of glochidia in the Danube system, whereas sedentary brown trout appear to be the most important hosts at a local scale.
Successful infection of suitable hosts and the maintenance of these host–parasite systems in calcareous water were demonstrated in this study. These results indicate that neither the infection process nor the encystment phase of freshwater pearl mussels is dependent on low lime concentrations.
The results of this study suggest that careful selection and management of appropriate host fish strains is mandatory for sustainable conservation management of freshwater pearl mussel populations. Copyright © 2010 John Wiley & Sons, Ltd.
Synthesis and Pharmacological Evaluation of Some 4‐Oxo‐quinoline‐2‐carboxylic Acid Derivatives as Anti‐inflammatory and Analgesic Agents
Authors: Mazzoni Orazio , Esposito Giovanni , Diurno Maria Vittoria , Brancaccio Diego , Carotenuto Alfonso , Grieco Paolo , Novellino Ettore , Filippelli Walter 
Published: October 2010

AbstractThe synthesis and the pharmacological activity of a series of 1‐aroyl derivatives of kynurenic acid methyl ester (4‐oxo‐quinolin‐2‐carboxy methyl (KYNA) esters), structurally related to NSAID indomethacin are described. The derivatives were screenedin vivofor anti‐inflammatory and analgesic activities. Most of the compounds exhibited good anti‐inflammatory and analgesic activities. An automatic docking of the synthesized compounds was performed using X‐ray structures of COX‐1 and COX‐2. Docking results are in good accordance with the experimental biological data.
Chimeric avidin shows stability against harsh chemical conditions—biochemical analysis and 3D structure
Authors: Määttä Juha A.E. , Eisenberg‐Domovich Yael , Nordlund Henri R. , Hayouka Ruchama , Kulomaa Markku S. , Livnah Oded , Hytönen Vesa P. 
Published: October 2010

AbstractAvidin and its bacterial analog streptavidin have been widely used in applications in life sciences. Recently, we described a highly thermostable engineered avidin, called chimeric avidin, which is a hybrid of avidin and avidin‐related protein 4. Here, we report a protocol for pilot‐scale production in E. coli and the X‐ray structure of chimeric avidin. The ligand‐binding properties of chimeric avidin were explored with isothermal titration calorimetry. We found chimeric avidin to be more stable against various harsh organic solvents at elevated temperatures compared to avidin and streptavidin. The properties of chimeric avidin make it a potential tool for new applications in biotechnology. Biotechnol. Bioeng. 2011; 108:481–490. © 2010 Wiley Periodicals, Inc.
Effects of water miscible organic solvents on the activity and conformation of the baeyer–villiger monooxygenases from Thermobifida fusca and Acinetobacter calcoaceticus: A comparative study
Authors: Secundo Francesco , Fialà Stefano , Fraaije Marco W. , de Gonzalo Gonzalo , Meli Massimiliano , Zambianchi Francesca , Ottolina Gianluca 
Published: October 2010

AbstractA broader exploitation of enzymes in organic synthesis can be achieved by increasing their tolerance toward organic solvents. In this study, the stability and activity of Baeyer–Villiger monooxygenases from Thermobifida fusca (PAMO) and Acinetobacter sp. (CHMO) in the presence of water miscible organic solvents were compared. PAMO was more stable than CHMO. The concentration of solvent (v/v) at which it halved its activity (C50) was 4‐ to 16‐fold higher than that observed for CHMO. For PAMO, the C50 varied from 16% to 55% of solvent and followed the destabilizing order methanol < ethanol < 1,4‐dioxane < acetonitrile < trifluoroethanol. In the case of CHMO, the maximal C50 was 7% with methanol and even lower with the other solvents. Therefore, methanol was the most tolerated solvent. In the case of PAMO, methanol induced a significant increase of enzyme activity (up to fivefold), which was optimal at 20% (v/v) solvent. Only minor spectral variations were observed with PAMO in 20% methanol, suggesting that the increase of activity observed in this condition is not due to marked conformational changes. Fluorescence and circular dichroism analyses showed that the lower stability of CHMO toward organic solvent correlates with a more pronounced destructive effect on its secondary and tertiary structure. A possible rationale for the higher stability of PAMO could be inferred from inspection of the PAMO and CHMO (two enzymes of similar size) structure, which revealed a higher (up to twofold) number of ionic bridges in PAMO with respect to CHMO. Biotechnol. Bioeng. 2011; 108:491–499. © 2010 Wiley Periodicals, Inc.