bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study on effect of duration of the ultrasonication process on solvent‐free polyurethane/organoclay nanocomposite coatings: Structural characteristics and barrier performance analysis
Authors: Heidarian M. , Shishesaz M. R. 
Published: July 2012

AbstractIn this study, effect of duration of ultrasonication process on structural characteristics and barrier properties of solvent‐free castor oil‐based polyurethane (PU)/organically modified montmorillonite (OMMT) nanocomposites was investigated. A series of PU/OMMT composites were synthesized by in situ polymerization technique through an ultrasonication‐assisted process at various processing durations. Effect of ultrasonication duration on de‐agglomeration of clay stacks in castor oil dispersions was evaluated by optical microscopy, sedimentation test, and viscosity measurement. Wide angle X‐ray diffraction and Fourier‐transform infrared spectroscopy were employed to investigate the effect of processing time on degree of delamination of clay platelets and interfacial strength between clay layers and PU matrix. Also, surface morphology of the nanocomposites was analyzed by atomic force microscopy. The results showed that by increasing the ultrasonication time up to 60 min, the size of clay agglomerates decreased and the interlayer spacing of clay platelets increased. To evaluate the effect of ultrasonication duration on transport properties of the PU/OMMT composites, diffusion coefficient and permeability were determined through water uptake test. Electrochemical impedance spectroscopy was carried out to analyze the barrier properties and to evaluate the corrosion performance of these composite coatings on carbon steel panels. It was found that by increasing sonication time, the barrier property of nanocomposites against diffusion of water molecules improved, which is due to further separation of clay platelets, enhancement of the traveling pathways for water molecules and improvement of interactions between the two components. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Thermodynamic interactions of EVA copolymer‐solvent systems by inverse gas chromatography measurements
Authors: Camacho Javier , Díez Eduardo , Ovejero Gabriel , Díaz Ismael 
Published: July 2012

AbstractThe solubility parameter and the Flory–Huggins interaction parameter of two EVA (ethylene–vinyl acetate) copolymers, each one with different vinyl acetate content, are calculated by using inverse gas chromatography technique. The influence of the vinyl acetate percentage is analyzed and indicates that the polymer–solvent interactions are stronger in the case of the copolymer with the highest vinyl acetate percentage. The results also point to the fact that the most favorable solvents for the studied materials are the aromatic‐type ones. Finally, from the calculated values of the polymer solubility parameter (16.3 MPa0.5 for EVA 460 and 15.1 MPa0.5 for EVA410, at 50°C), it can be noticed that the solubility parameter of the EVA copolymer with the largest vinyl acetate content is the closest to the solubility parameter of pure vinyl acetate. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Electrical and mechanical properties of the potassium permanganate treated short sisal fiber reinforced epoxy composite in correlation to the macromolecular structure of the reinforced fiber
Authors: Patra Annapurna , Bisoyi Dillip K. , Manda Prem K. , Singh A. K. 
Published: July 2012

AbstractSisal fibers are treated with potassium permanganent (KMnO4)—acetone solution for various concentrations for different soaking time period prior to the composite fabrication. Small angle X‐ray scattering (SAXS) and wide angle X‐ray diffraction (WAXD) analysis shows significant change in the macromolecular and the crystallographic parameters of the fiber, respectively, after the treatment. Fiber treated with 0.05% KMnO4‐acetone solution for 2 min (05K2) is found to have highest degree of crystalinity, crystallite size, and bulk density. Enhanced tensile and flexural strength of the 05K2 reinforced epoxy composite (05KC2) is attributed to the increase surface roughness of the fiber. Lower values of dielectric constant (εr), dielectric loss (tan δ) and improved volume resistivity (ρ) for the 05KC2 composite may be due to the hindered molecular motion of the polymeric chains at the composite interface resulting from the better interlocking between the fiber and matrix. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Preparation and properties of molded blends of wheat gluten and cationic water‐borne polyurethanes
Authors: Zhong Ni , Yuan Qiaolong 
Published: July 2012

AbstractCationic water‐borne polyurethanes (CWPU) were prepared and blended with wheat gluten (WG) in aqueous dispersion. The freeze‐dried blend powders of WG/CWPU were thermally compression‐molded into sheets. The tensile strength of the WG/CWPU blends decreased with increasing CWPU content, showing a relationship between the composition of the sheets and their mechanical properties. FTIR spectra reveal that the free carbonyl in the blend results in a decrease in the hydrogen‐bonding interaction of the WG. SEM images show that the morphology of the cross‐sections of the blends is homogenous. The dynamic thermal behavior of the blends illustrates that the WG is plasticized by CWPU, with the result that the relaxation transition of the WG becomes broader and the temperature transition of WG changes slightly. The water resistance of the WG was also improved by blending it with the CWPU. Biodegradation of the blends in soil resulted in a loss in mass of the samples of more than 60% w/w after burial for 15 days. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Surface coated iron particles via atom transfer radical polymerization for thermal–oxidatively stable high viscosity magnetorheological fluid
Authors: Sutrisno Joko , Fuchs Alan , Sahin Huseyin , Gordaninejad Faramarz 
Published: July 2012

AbstractA surface grafting technique for poly(2‐fluorostyrene) onto iron particles via atom transfer radical polymerization (ATRP) is described. Grafted poly(2‐fluorostyrene)–iron particles were synthesized by immobilizing 2‐4(‐chlorosulfonylphenyl)‐ethyltrichlorosilane to the iron particles through the covalent bond of a silanol group, followed by the polymerization of 2‐fluorostyrene monomer. The grafted polymer–iron particles display a higher thermal transition temperature compared to bulk polymer because the covalent bond between the polymer backbone and the surface of the iron particles restricts the molecular mobility. The molecular weight of the synthesized poly(2‐fluorostyrene) has been measured and it has a narrow molecular weight distribution (Mw/Mn < 1.1). From thermogravimetric analysis, the thermal stability of poly(2‐fluorostyrene) is superior to polystyrene. Also, the high viscosity magnetorheological fluid (HVMRF) prepared from surface coated iron particles has excellent thermo–oxidative stability, having nearly constant viscosity. These materials exhibit a large increase in shear yield stress for the off‐ and on‐state as compared to a benchmark high viscosity magnetorheological fluid (HVMRF) and ‐coated iron particle HVMRF. In addition, this type of fluid eliminates iron particle settling which is a common problem found in traditional magnetorheological fluids (MRFs). © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis of a phenol copolymer with horseradish peroxidase and the study of its structure–property relations
Authors: Lv Shenghua , Li Di , Ju Haobo , Ma Yujuan , Qiu Chaochao , Zhang Guoyun 
Published: July 2012

AbstractA phenol copolymer was synthesized by the free‐radical copolymerization of p‐hydroxybenzaldehyde (HBA) and p‐phenolsulfonate with horseradish peroxidase (HRP)/H2O2 as an initiator. The synthesis process included aldehyde protection via acetalization, enzymatic polymerization, and aldehyde deprotection via hydrolysis of acetals. The effects of the monomer ratio and the HRP and H2O2 composites on the properties of poly(p‐hydroxybenzaldehyde‐co‐p‐phenolsulfonate) [poly(HBA‐co‐PS)] were investigated by the determination of the shrink temperature (Ts) of tanned leather. The poly(HBA‐co‐PS) structure was characterized by Fourier transform infrared spectroscopy, NMR, UV spectroscopy, and gel permeation chromatography. The mechanism of enzymatic copolymerization, including initiation, H transfer, radical transfer, coupling, termination, differed from that of traditional free‐radical polymerization. A remarkable characteristic was that poly(HBA‐co‐PS) had a large conjugated structure in its molecules that markedly improved the activity of the aldehyde and hydroxyl groups and showed easy crosslinking in the leather fibers. The applied results showed that the Ts of tanned leather with poly(HBA‐co‐PS) reached 83.6°C. Poly(HBA‐co‐PS) could be used as agent for tanning leather. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013
Comparison of static vehicle flow assignment methods and microsimulations for a personal rapid transit network
Authors: Schweizer Joerg , Danesi Antonio , Rupi Federico , Traversi Emiliano 
Published: July 2012

SUMMARYThis article describes a static assignment method for a class of emerging public transport systems called personal rapid transit (PRT). PRT is a fully automated public transportation system where small‐size vehicles run on exclusive guideways.Because of its automated, on‐demand service, PRT must be able to automatically reroute empty vehicles after use to supply stations with waiting passengers. Consequently, any PRT traffic assignment must take into account the flow of empty vehicles as well as the flow of vehicles with passengers.The PRT assignment methods described in this work are based on linear programming models. One of the assignment methods has been applied to a realistic PRT network, and the statically assigned flows have been compared with averaged link flows produced by a PRT microsimulation. It is shown that the proposed static assignment method is not only useful to identify capacity bottlenecks of the planned PRT network but also serves to benchmark the microsimulator's vehicle management algorithms. Copyright © 2012 John Wiley & Sons, Ltd.
Serum peptidome patterns for early screening of esophageal squamous cell carcinoma
Authors: Fan Nai‐Jun , Gao Chun‐Fang , Zhao Guang , Wang Xiu‐Li , Qiao Liang 
Published: July 2012

AbstractEsophageal squamous cell carcinoma (ESCC) is one of the most common cancers in the world. Early diagnosis is critical for guiding the therapeutic management of ESCC. The present study aims to determine serum peptidome patterns for diagnosing ESCC. To identify novel peptidome patterns for diagnosing ESCC, sera from 31 healthy volunteers and 32 ESCC patients were subjected to a comparative proteomic analysis using a ClinProt™ Kit combined with mass spectrometry (MS). This approach enables the determination of peptidome patterns that can differentiate between ESCC sera and sera from healthy volunteers. For further validation, the diagnostic and differential diagnostic capabilities of the peptidome patterns were verified blindly by using an independent group of sera, consisting of sera from 31 ESCC patients, 33 healthy volunteers, 38 colorectal patients, and 36 gastric cancer patients. A Quick Classifier Algorithm was used to construct the peptidome patterns for the identification of ESCC from the control samples. Five of the identified peaks at mass to charge ratios 759, 786, 1,866, 3,316, and 6,634 were used to construct the peptidome patterns with almost 100% accuracy. Furthermore, the peptidome patterns could also differentiate the validation group with high accuracy. These results suggest that the ClinProt™ Kit combined with MS achieves significantly high accuracy for ESCC diagnosis and differential diagnosis.
Photophysical processes of an intramolecular charge transfer fluorescent dye with carbazole units
Authors: Gao Shouqin , Hao Liling , Li Junfen , Lin Peihua , Li Duxin , Shuang Shaomin , Dong Chuan 
Published: July 2012

ABSTRACTA carbazole‐based compound with intramolecular charge transfer (ICT) characteristics, 3,6‐bis‐((N‐ethylcarbazole‐3‐)‐propene‐1‐keto)‐N‐ethylcarbazole (BCzPCz) was synthesized by N‐alkylation, acetylation and aldol condensation. BCzPCz was further confirmed by IR and 1 H NMR. The central N‐ethylcarbazole was connected with two N‐ethylcarbazole units through the propenone group in BCzPCz. N‐ethylcarbazole and carbonyl groups were electron donors (D) and acceptors (A), respectively. The UV–vis absorption and fluorescence characteristics of BCzPCz were also investigated in different solvents. Solvatochromism was attributed to ICT complex formation in singlet excited state. Magnitude of the change in the dipole moment was 24.78 D according to Lippert‐Mataga equation. Fluorescence of BCzPCz was significantly affected by pH and was quenched in acidic medium. Fluorescence quantum yield of BCzPCz was 0.516 in ethanol. Experimental results showed its potential use as a fluorescence probe and as two‐photon absorption material. Copyright © 2012 John Wiley & Sons, Ltd.
Synthesis of homogenous disulfide cross‐linked polypeptides by iterative reducible ligation
Authors: Ericson Mark D. , Rice Kevin G. 
Published: July 2012

AbstractA new method of directed solution phase synthesis of polypeptides linked through iterative formation of disulfide bonds is reported. Four dodecapeptides were successfully ligated into a single 48 amino acid polypeptide using an N‐terminal Fmoc‐thiazolidine and a novel acidic silver trifluoromethanesulfonate thiazolidine hydrolysis to achieve efficient ligation in the presence of internal disulfide bonds. The approach allows the synthesis of homogeneous disulfide cross‐linked polypeptides that have application in gene delivery by undergoing a reductively triggered release of DNA. © 2012 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 98: 510–517, 2012.
Enhancement of the enzymatic digestibility of sugarcane bagasse by steam pretreatment impregnated with hydrogen peroxide
Authors: Rabelo Sarita Cândida , Vaz Rossell Carlos Eduardo , de Moraes Rocha George Jackson , Zacchi Guido 
Published: July 2012

AbstractSugarcane bagasse was subjected to steam pretreatment impregnated with hydrogen peroxide. Analyses were performed using 23 factorial designs and enzymatic hydrolysis was performed at two different solid concentrations and with washed and unwashed material to evaluate the importance of this step for obtaining high cellulose conversion. Similar cellulose conversion were obtained at different conditions of pretreatment and hydrolysis. When the cellulose was hydrolyzed using the pretreated material in the most severe conditions of the experimental design (210°C, 15 min and 1.0% hydrogen peroxide), and using 2% (w/w) water‐insoluble solids (WIS), and 15 FPU/g WIS, the cellulose conversion was 86.9%. In contrast, at a milder pretreatment condition (190°C, 15 min and 0.2% hydrogen peroxide) and industrially more realistic conditions of hydrolysis (10% WIS and 10 FPU/g WIS), the cellulose conversion reached 82.2%. The step of washing the pretreated material was very important to obtain high concentrations of fermentable sugars. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012
Rational optimization of culture conditions for the most efficient ethanol production in Scheffersomyces stipitis using design of experiments
Authors: Unrean Pornkamol , Nguyen Nhung H. A. 
Published: July 2012

AbstractOptimization of culture parameters for achieving the most efficient ethanol fermentation is challenging due to multiple variables involved. Here we presented a rationalized methodology for multi‐variables optimization through the design of experiments DoE approach. Three critical parameters, pH, temperature, and agitation speed, affecting ethanol fermentation in S. stipitis was investigated. A predictive model showed that agitation speed significantly affected ethanol synthesis. Reducing pH and temperature also improved ethanol production. The model identified the optimum culture conditions for the most efficient ethanol production with the yield and productivity of 0.46 g/g and 0.28 g/l h, respectively, which is consistent with experimental observation. The results also indicated the scalability of the model from shake flask to bioreactor. Thus, DoE is a promising tool permitting the rapid establishment of culture conditions for the most efficient ethanol fermentation in S. stipitis. The approach could be useful to reduce process development time in lignocellulosic ethanol industry. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012
Investigating the use of column inserts to achieve better chromatographic bed support
Authors: Lan Tian , Gerontas Spyridon , Smith Graeme R. , Langdon John , Ward John M. , Titchener‐Hooker Nigel J. 
Published: July 2012

AbstractChromatography plays an important role in the downstream processing of proteins. Over the past years, there has been a steady move toward the adoption of more rigid, porous particles to combine ease of manufacture with increased levels of productivity. The latter is still constrained by the onset of compression where the level of wall support becomes incapable of withstanding flow‐induced particle drag. In this study, we investigate how, by the installation of cylindrical column inserts, it is possible to enhance the level of wall support. Experiments were conducted to examine the effect of the position of the insert in the column, and also of the insert dimensions on the critical velocity at which the onset of compression occurs. It was found that when installed at the bottom of the column, inserts can provide up to a 20% increase in critical velocity without significantly affecting column hydrodynamics, as measured by the level of axial dispersion. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012
Growing Up with Child Sexual Abuse in an Experimental Commune: Making Sense of Narrative Variation
Authors: Gibson Kerry , Morgan Mandy 
Published: July 2012

ABSTRACTThe legitimacy of adult's accounts of child sexual abuse depends on the consistency of the story they tell about this experience. But there are a variety of influences that conspire to create dynamic variation in retrospective accounts of child sexual abuse. In a study of an experimental New Zealand commune called Centrepoint, participants showed considerable variation in accounting for the child sexual abuse that was known to have occurred there. We used a narrative methodology to show the variation between stories that highlighted abuse and suffering and others that represented an idyllic childhood within which sex between children and adults was normalised. There was also considerable variation within individual participant's accounts. The variation within and between accounts was shaped by features such exposure to contradictory experiences, different social positioning in relation to child sexual abuse, shifts in memory and interpretation over time, differences between insider and outsider perspectives on child sexual activity at the commune and alternative perspectives on victimhood. This research challenges the mythology that accounts of child sexual abuse should be expected to be clear and consistent. Instead, variation should be treated the rule rather than the exception in these accounts. Copyright © 2012 John Wiley & Sons, Ltd.
Substrate‐Induced Conformational Change and Isomerase Activity of Dienelactone Hydrolase and its Site‐Specific Mutants
Authors: Walker Ian , Hennessy James E. , Ollis David L. , Easton Christopher J. 
Published: July 2012

AbstractStudies of the interactions of dienelactone hydrolase (DLH) and its mutants with both E and Z dienelactone substrates show that the enzyme exhibits two different conformational responses specific for hydrolysis of each of its substrate isomers. DLH facilitates hydrolysis of the Z dienelactone through an unusual charge‐relay system that is initiated by interaction between the substrate carboxylate and an enzyme arginine residue that activates an otherwise non‐nucleophilic cysteine. The E dienelactone does not display this substrate–arginine binding interaction, but instead induces an alternate conformational response that promotes hydrolysis. Furthermore, the substitution of cysteine 123 for serine (C123S) in DLH, instead of inactivating the enzyme as is typical for this active‐site mutation, changes the catalysis from substrate hydrolysis to isomerisation. This is due to the deacylation of the acyl–enzyme intermediates being much slower, thereby increasing their lifetimes and allowing for their interconversion through isomerisation, followed by relactonisation.
High‐Potential Reversible Li Deintercalation in a Substituted Tetrahydroxy‐p‐benzoquinone Dilithium Salt: An Experimental and Theoretical Study
Authors: Barrès Anne‐Lise , Geng Joaquin , Bonnard Gaëtan , Renault Stéven , Gottis Sébastien , Mentré Olivier , Frayret Christine , Dolhem Franck , Poizot Philippe 
Published: July 2012

AbstractEfficient organic Li‐ion batteries require air‐stable lithiated organic structures that can reversibly deintercalate Li at sufficiently high potentials. To date, most of the cathode materials reported in the literature are typically synthesized in their fully oxidized form, which restricts the operating potential of such materials and requires use of an anode material in its lithiated state. Reduced forms of quinonic structures could represent examples of lithiated organic‐based cathodes that can deintercalate Li+ at potentials higher than 3 V thanks to substituent effects. Having previously recognized the unique electrochemical properties of the C6O6‐type ring, we have now designed and then elaborated, through a simple three‐step method, lithiated 3,6‐dihydroxy‐2,5‐dimethoxy‐p‐benzoquinone, a new redox amphoteric system derived from the tetralithium salt of tetrahydroxy‐p‐benzoquinone. Electrochemical investigations revealed that such an air‐stable salt can reversibly deintercalate one Li+ ion on charging with a practical capacity of about 100 mAh g−1 at about 3 V, albeit with a polarization effect. Better capacity retention was obtained by simply adding an adsorbing additive. A tetrahydrated form of the studied salt was also characterized by XRD and first‐principles calculations. Various levels of theory were probed, including DFT with classical functionals (LDA, GGA, PBEsol, revPBE) and models for dispersion corrections to DFT. One of the modified dispersion‐corrected DFT schemes, related to a rescaling of both van der Waals radii and s6 parameter, provides significant improvements to the description of this kind of crystal over other treatments. We then applied this optimized approach to the screening of hypothetical frameworks for the delithiated phases and to search for the anhydrous structure.
Synthesis and Catalytic Properties of Hybrid Mesoporous Materials Assembled from Polyhedral and Bridged Silsesquioxane Monomers
Authors: Díaz Urbano , García Teresa , Velty Alexandra , Corma Avelino 
Published: July 2012

AbstractA family of hybrid mesoporous materials with high temperature stability was obtained by the suitable covalent combination of two types of siloxane precursors. Specifically, cubic T8 polyhedral oligomeric (POSS) and aryl bridged silsesquioxane monomers (1,4‐bis(triethoxysilyl)benzene, BTEB) play the role of nanobuilders. An optimal molar ratio of the two precursors (5–25 mol % of total silicon content from the BTEB disilane) generated a homogenous, highly accessible, and well‐defined mesoporous material with hexagonal symmetry and narrow pore‐size distribution. Physicochemical, textural, and spectroscopic analysis corroborated the effective integration and preservation of the two different nanoprecursors, thereby confirming the framework of the mesoporous hybrid materials. A post‐synthesis amination treatment allowed the effective incorporation of amino groups onto the aryl linkers, thereby obtaining a stable and recyclable basic catalyst for use in CC bond‐formation processes.