bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of fiber orientation on Mode I fracture toughness of CFRP
Authors: Miyagawa Hiroaki , Sato Chiaki , Ikegami Kozo 
Published: November 2009

AbstractThe effect of fiber orientations on fracture toughness of carbon fiber reinforced plastics (CFRP) in Mode I loading was investigated using double cantilever beam (DCB) specimens, based on mesoscopic mechanics. Mesoscopic interlaminar fracture toughness of 0//0 interphase of CFRP was evaluated with mesoscopic finite element models using experimental data. The fracture surface roughness was observed by confocal laser scanning microscopy. Then the mesoscopic interlaminar fracture toughness of CFRP was correlated with the fracture surface roughness. Additionally, the change of the Mode I macroscopic fracture toughness of CFRP was experimentally measured with changing the numbers of 0 and ±θ layers of DCB specimens. The correlation between the fracture toughness of 0//0 and θ//−θ interphases was discussed and a novel procedure was proposed to predict the macroscopic fracture toughness of θ//−θ interphase using finite element method (FEM). The fracture toughness of θ//−θ interphase analyzed by FEM was finally compared with the experimental results to verify the proposed prediction procedure. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Studies on synthesis and characterization of N‐alkyl terephthalamides using different amines from polyethylene terephthalate waste
Authors: Soni R. K. , Singh Swati , Dutt Krishna 
Published: November 2009

AbstractThis study deals with the degradation of polyethylene terephthalate (PET) waste through aminolysis with various amines. All of these degradation experiments were carried out at ambient temperature and at normal pressure. Although PET is known to be recycled in many ways, but still there is a need of development of other environment friendly recycling techniques. The amines used to study the degradation of PET waste were namely methylamine, ethylamine, and n‐butyl amine, respectively where the degradation of PET waste completes in 45 days. The aminolyzed products so obtained were characterized by using various conventional techniques such as spectroscopic techniques namely IR, NMR, and simultaneous differential scanning calorimeter (DSC). In the present research work, a useful method of PET recycling by using various amines was successfully established. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
A reactive polymer for toughening epoxy resin
Authors: Kuan Hsu‐Chiang , Dai Jia‐Bin , Ma Jun 
Published: November 2009

AbstractEpoxy resins are hardly toughened by low weight content of tougheners. In this study, 5 wt % polyurea was adopted to significantly toughen piperidine‐cured epoxy, as fracture toughness improved from 0.78 to 1.98 MPa m1/2. We focused on the reactions and morphology evolution of epoxy/polyurea mixture. The polyurea molecular weight was reduced by the exchange reactions of polyurea with epoxy during mixing, as evidenced by gel permeation chromatograph and Fourier transform infrared spectroscopy. As a result, epoxy molecules were chemically bonded with polyurea, improving particle content and interface thickness. Transmission electron microscope observation shows that (a) polyurea in situ formed nanoparticles in matrix which subsequently aggregate into micron‐sized particles of thick interface with matrix; and (b) the particles became less stainable with increasing the mixing time, because the reactions promoted high levels of crosslink density of the particles which were thus more resistant to the diffusion of staining chemicals. Longer mixing time improved, obviously, the fracture toughness of epoxy/polyurea composite. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis of a novel series of propargyloxyphenyl maleimides and their characterization as thermal‐resistance resins
Authors: Liu Feng , Liu Jinge , Zhao Tong 
Published: November 2009

AbstractNovel thermosetting monomers possessing both maleimide and propargyl groups were first designed and synthesized. The monomers included N‐(2‐propargyloxyphenyl) maleimide (2‐PPM), N‐(3‐propargyloxyphenyl) maleimide (3‐PPM), and N‐(4‐propargyloxyphenyl) maleimide (4‐PPM), and their structures were confirmed with Fourier transform infrared (FTIR) spectroscopy, 1H‐NMR, and elemental analysis. The cure behaviors of these monomers were characterized with differential scanning calorimetry and FTIR spectroscopy, and the results indicated that the monomers had a broader processing window than normal bismaleimide (BMI) resins. The thermal properties of the cured monomers were characterized with thermogravimetric analysis and dynamic mechanical analysis. The 5% mass loss temperatures of the cured monomers were high (ca. 400°C), and the glass‐transition temperatures of cured 2‐PPM, 3‐PPM, and 4‐PPM were 386, 373, and 387°C, respectively, which were much higher than those of typical commercial blended BMI resins. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation and thermal characterization of films containing liquid crystals in a cellulose acetate substrate for externally regulated applications
Authors: Martínez‐Felipe Alfonso , Ballester‐Sarrias Enrique , Imrie Corrie T. , Ribes‐Greus Amparo 
Published: November 2009

AbstractTwo different series of polymer dispersed liquid crystal (PDLC) films were prepared for their future use as externally controlled electrolytes in direct methanol fuel cells (DMFC). The liquid crystals used in this work were commercial cholesteryl oleyl carbonate (COC) and n‐(4‐methoxybencylidine)‐4‐butylanilyne (MBBA); cellulose acetate (CA) was used as the polymer substrate. All the films were characterized by differential scanning calorimetry (DSC) and Thermogravimetric analysis (TGA) to analyze the existence of interactions between the components, the modification of the liquid crystal behavior and the thermal stability of the films. The two series of films exhibited very different behaviors. While the films containing CA and COC maintained most of the properties characteristic of the pure components, including the COC mesomorphism, the analysis of films containing CA and MBBA revealed the existence of strong interactions between the components that promoted the inhibition of the MBBA mesomorphic behavior. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Nanocomposites of poly(vinylidene fluoride) with multiwalled carbon nanotubes
Authors: Huang Wenwen , Edenzon Kyle , Fernandez Luis , Razmpour Shabnam , Woodburn Jenna , Cebe Peggy 
Published: November 2009

AbstractThe preparation and characterization of nanocomposites of poly(vinylidene fluoride), PVDF, with acid treated multiwalled carbon nanotubes (MWCNT) with a wide composition range, from 0.1 to 5.0% MWCNT by weight, is reported. Effect of uniaxial orientation by zone drawing on these nanocomposites is discussed and compared with unoriented compression molded films. Static room temperature two‐dimensional wide angle X‐ray scattering and Fourier transform infrared spectroscopy were used for phase identification. Differential scanning calorimetry, polarizing optical microscopy, dynamic mechanical analysis (DMA), and thermogravimetic analysis (TGA) were used to study the thermal and mechanical properties. Incorporation of MWCNT into PVDF has no obvious effect in forming beta phase crystal in the PVDF/MWCNT bulk films, while zone drawing cause a significant alpha to beta transition in PVDF/MWCNT. Results indicate that MWCNTs act as nucleation agent during crystallization and slightly increase the degree of crystallinity of PVDF/MWCNT bulk films. TGA indicates the thermal stability is improved when MWCNT concentration increases for unoriented PVDF/MWCNT film. The modulus also increases significantly when MWCNT concentration increases. The glass transition temperature measured by the peak position of tanδ from DMA does not change with MWCNT concentration, but a slightly higher glass transition can be obtained by zone drawing. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Chain extension reaction in solid‐state polymerization of recycled PET: The influence of 2,2′‐bis‐2‐oxazoline and pyromellitic anhydride
Authors: Nascimento Christine R. , Azuma Chiaki , Bretas Rosário , Farah Marcelo , Dias Marcos L. 
Published: November 2009

AbstractConventional and chain extended‐modified solid‐state polymerization (SSP) of postconsumer poly(ethylene terephthalate) (PET) from beverage bottles was investigated. SSP was carried out at several temperatures, reaction times, and 2,2′‐bis‐2‐oxazoline (OXZ) or pyromellitic anhydride (ANP) concentrations. The OXZ was added by impregnation with chloroform or acetone solution. Higher molecular weights were reached when the reaction was carried out with OXZ, resulting in bimodal distribution. The molecular weights of the flakes reacted at 230°C for 4 h were 85,000, 95,000, and 100,000 for samples impregnated with 0, 0.5, and 1.25 wt % OXZ solution, respectively. In the case of reactions with ANP, branched chains were obtained. The thermal and thermal‐mechanical‐dynamic properties of these high‐molecular‐weight recycled PET were determined. For OXZ‐reacted samples, the reduction of crystallinity was observed as the reaction time was increased, becoming evident the destruction of the crystalline phase. The chain extended samples did not show changes in thermal relaxations or thermal degradation behavior. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Processing and mechanical behavior of carbon black graded rubber compounds
Authors: Ahankari Sandeep S. , Kar Kamal K. 
Published: November 2009

AbstractFunctionally graded rubber compounds (FGRCs) were prepared by construction based method. The matrix used was natural rubber (NR). Amorphous carbon black (N‐330) was used as grading material. The gradation of nanoparticles in a rectangular geometry comprised the variation of particle volume fraction along thickness direction. Its performance was evaluated for structural application through various mechanical and surface properties like tensile strength, modulus, tear strength, elongation at break, hardness, fracture surface by scanning electron microscopy, etc. At the same percentage of nanofiller loading, FGRCs show enhanced properties, i.e., modulus and tear strength (in some grades) compared to uniformly dispersed rubber compounds (UDRCs). Modulus of FGRCs, for a given particular stacking sequence of the layers, increases as much as by 275% compared to UDRCs. The ultimate properties like tensile strength and elongation at break made up for the modulus enhancement that decreases to as minimum as 50 and 80%, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis of reactive soybean oils for use as a biobased thermoset resins in structural natural fiber composites
Authors: Adekunle Kayode , Åkesson Dan , Skrifvars Mikael 
Published: November 2009

AbstractBiobased thermosets resins were synthesized by functionalizing the triglycerides of epoxidized soybean oil with methacrylic acid, acetyl anhydride, and methacrylic anhydride. The obtained resins were characterized with FTIR, 1H‐NMR, and 13C‐NMR spectroscopy to confirm the functionalization reactions and the extent of epoxy conversion. The viscosities of the methacrylated soybean oil resins were also measured for the purpose of being used as a matrix in composite applications. The cross‐linking capability was estimated by UV and thermally initiated curing experiments, and by DSC analysis regarding the degree of crosslinking. The modifications were successful because up to 97% conversion of epoxy group were achieved leaving only 2.2% of unreacted epoxy groups, which was confirmed by 1H‐NMR. The 13C‐NMR confirms the ratio of acetate to methacrylate methyl group to be 1 : 1. The viscosities of the methacrylated soybean oil (MSO) and methacrylic anhydride modified soybean oil (MMSO) were 0.2 and 0.48 Pas, respectively, which indicates that they can be used in resin transfer molding process. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Evidence for a Rapid Degenerate Hetero‐Cope‐Type Rearrangement in [Cp*W(S)2S‐CH2‐CHCH2]
Authors: Eweiner Florian , Senda Shunsuke , Bergander Klaus , Mück‐Lichtenfeld Christian , Grimme Stefan , Fröhlich Roland , Aoyama Michiko , Kawaguchi Hiroyuki , Ohki Yasuhiro , Matsumoto Tsuyoshi , Kehr Gerald , Tatsumi Kazuyuki , Erker Gerhard 
Published: November 2009

AbstractTreatment of the salt [PPh4]+[Cp*W(S)3]− (6) with allyl bromide gave the neutral complex [Cp*W(S)2S‐CH2‐CHCH2] (7). The product 7 was characterized by an X‐ray crystal structure analysis. Complex 7 features dynamic NMR spectra that indicate a rapid allyl automerization process. From the analysis of the temperature‐dependent NMR spectra a Gibbs activation energy of ΔG≠ (278 K)≈13.7±0.1 kcal mol−1 was obtained [ΔH≠≈10.4±0.1 kcal mol−1; ΔS≠≈−11.4 cal mol−1 K−1]. The DFT calculation identified an energetically unfavorable four‐membered transition state of the “forbidden” reaction and a favorable six‐membered transition state of the “Cope‐type” allyl rearrangement process at this transition‐metal complex core.
Poly‐quadratic stability of discrete‐time nonlinear systems in Takagi‐Sugeno's form
Authors: Ding Baocang 
Published: November 2009

AbstractThis paper studies poly‐quadratic stability of nonlinear systems represented by a Takagi‐Sugeno (T‐S) discrete fuzzy model. A system is poly‐quadratically stable when its stability can be verified by a parameter dependent Lyapunov function. There are already some results in this area. This paper, however, presents less conservative results by adopting more slack‐matrix‐variables in the linear matrix inequalities (LMIs). The parallel distributed compensation (PDC) law is utilized in both the analysis and the synthesis problems. The effectiveness of the new results in this paper is validated by a simulation example. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Observers for a class of nonlinear systems with time‐delay
Authors: Zhou Lei , Xiao Xiaoqing , Lu Guoping 
Published: November 2009

AbstractIn this paper, the issue of observer designs for a class of nonlinear continuous‐time systems with time‐delay is addressed, where the nonlinear function is not necessarily Lipschitz. It is shown that both full‐order and reduced‐order observers can be obtained by means of the same linear matrix inequality. A numerical example is presented to show the effectiveness of the proposed approach. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
The effect of behavioral skills training with general‐case training on staff chaining of child vocalizations within natural language paradigm
Authors: Seiverling Laura , Pantelides Maria , Ruiz Henry H. , Sturmey Peter 
Published: November 2009

AbstractThis study used behavioral skills training (BST) and general‐case training (GCT) in which the experimenter simulated child performance to teach three staff to conduct NLP and response chaining to increase three‐link vocal chains in three children with autism. Staff increased their correct NLP performance during post‐training in comparison to baseline. Two of three children emitted more vocal chains following training. This study demonstrated that BST and GCT were effective in training NLP and response chaining. When assessing social validity, both Board Certified Behavior Analysts (BCBAs) and teachers did not indicate an increase in staff members' teaching skills. Future research should develop effective technologies to chain vocal behavior and to teach staff and parents to implement response chaining. Copyright © 2009 John Wiley & Sons, Ltd.
New techniques to detect oxidative stress markers: Mass spectrometry‐based methods to detect isoprostanes as the gold standard for oxidative stress in vivo
Authors: Yin Huiyong 
Published: November 2009

AbstractFree radical‐induced lipid oxidation under oxidative stress has been implicated in a number of human diseases. Isoprostanes (IsoPs), isomers of prostaglandins, are one of the major classes of oxidation products derived from this oxidation process. Measurement of the levels of IsoPs by Mass Spectrometry‐based methods has become the “gold standard” biomarker of oxidative stress in vivo. Significant advances have been made in understanding this important pathway of lipid peroxidation since the discovery of IsoP formation in vivo 18 years ago. Studies from our laboratory and others are discussed that have provided insights into the mechanism of formation. Furthermore, new independent studies have demonstrated that IsoPs are the most reliable available marker of lipid peroxidation in vivo, and recent work examining IsoP formation has provided valuable information about the pathogenesis of numerous human diseases. Thus, the complexity of the IsoP pathway has expanded, providing novel insights into mechanisms of lipid peroxidation in vivo and allowing investigators to explore the role of oxidative stress in human disease.
Clinical relevance of plasma homocysteine levels in Taiwanese patients with coronary artery disease
Authors: Cheng Mei‐Ling , Ho Hung‐Yao , Lin Jui‐Fen , Chan Err‐Cheng , Chiu Daniel Tsun‐Yee , Chen Yo‐Cheng 
Published: November 2009

AbstractHomocysteine (Hcy) has recently been considered as a risk factor for cardiovascular disease. Coronary artery disease (CAD) is the third most common cause of mortality in Taiwan. The objective of our present study is to delineate the relationship between the plasma Hcy level and CAD in Taiwanese using an improved enzymatic method. Blood samples were collected from 86 CAD patients, which include 38 patients with acute coronary syndrome (ACS) and 48 patients with stable CAD, and 89 controls. Plasma Hcy levels were measured by HPLC and enzymatic methods. Plasma Hcy levels were 8.27 ± 1.74, 8.50 ± 1.88 and 11.76 ± 4.58 μM in normal controls, patients with stable CAD and those with ACS, respectively. Plasma Hcy levels were elevated in the cohort of ACS patients, as compared with those of normal controls or patients with stable CAD. Within the CAD group, patients with the highest quartile Hcy level (10.18‐23.73 μM) had a significantly higher odd ratio for ACS, as compared with those with the lowest quartile Hcy level after multivariate adjustment. Plasma Hcy concentration can be used as an independent risk factor of ACS, particularly for those with a history of CAD. Moreover, our improved enzymatic assay can be automated for large‐scale screening of high‐risk cohorts.
Functional expression and characterization of human 101F6 protein, a homologue of cytochrome b561 and a candidate tumor suppressor gene product
Authors: Recuenco Mariam C. , Fujito Masamitsu , Sakamoto Yoichi , Tsubaki Motonari , Rahman M. D. Motiur , Takeuchi Fusako 
Published: November 2009

AbstractA highly hydrophobic protein with six transmembrane structure that is coded by the candidate tumor suppressor gene 101F6 located in the human chromosome 3p.21.3 and a possible member of the cytochrome b 561 protein family was expressed, purified, and characterized in its functional form for the first time. The protein was heterologously expressed in methylotrophic yeast Pichia pastoris as a fusion protein containing a C‐terminal thrombin‐specific sequence and an 8‐His residue tag. Purification was achieved by ion exchange chromatography on DEAE‐Sepharose and affinity chromatography on Ni‐NTA‐Sepharose. SDS‐PAGE analysis revealed a single protein band with an estimated molecular weight of 26 kDa, while Western blot and MALDI‐TOF‐MS analysis confirmed the presence of the cytochrome b561 specific sequence in the protein. The 101F6 protein was found to be reducible by ascorbate efficiently and to have two midpoint potentials at +89.5 and +13.1 mV, slightly lower than the corresponding values of +155 and +62 mV, respectively, of bovine adrenal cytochrome b 561, despite a lower conservation of the putative ascorbate binding site sequence in the 101F6 protein. The “modified motif 1” sequence unique in 101F6 protein may be responsible for other molecular functions, such as protein‐protein interactions, in the endoplasmic membranes.
ECTO‐NOX (ENOX) proteins of the cell surface lack thioredoxin reductase activity
Authors: Bosneaga Elena , Kim Chinpal , Shen Bernard , Watanabe Takahiro , Morré D. James , Morre Dorothy M. 
Published: November 2009

AbstractThis study was to determine if ENOX proteins of the cell surface act as cell surface thioredoxin reductases. To measure formation of thiols a turbimetric insulin assay was used. No turbidity was observed with insulin alone or with insulin plus DTT. However, the combination of insulin + DTT + recombinant his‐tagged ENOX2 (tNOX) did result in increased turbidity. An ENOX1 (CNOX) preparation also resulted in turbidity changes. In contrast, we were unable to demonstrate ENOX2‐dependent insulin reduction by high density SDS‐PAGE. Inclusion of reduced serum albumin as a source of free thiols for the protein disulfide interchange activity catalyzed by ENOX2 failed to result in insulin reduction in the presence of ENOX2. A direct effect of ENOX2 on thioredoxin reduction in the presence of NADPH also was not observed. The DTNB assay for thioredoxin reductase activity also failed to reveal activity. Thus, ENOX proteins appear not to function as thioredoxin reductases at the cell surface nor do they appear to recognize reduced insulin as a substrate for protein disulfide‐thiol interchange. The enhanced turbidity of insulin solutions resulting from ENOX presence was traced to ENOX‐catalyzed insulin fibrillation either through nucleation enhancement or some other mechanism. Fibrillation was determined using Thioflavin T fluorescence which paralleled the turbimetric results and the formation of multimers (polymerization) observed on SDS‐PAGE.
Effects of hydrophobicity and anions on self‐assembly of the peptide EMK16‐II
Authors: Zou Dawei , Tie Zuoxiu , Lu Chunmei , Qin Meng , Lu Xiaomei , Wang Mu , Wang Wei , Chen P. 
Published: November 2009

AbstractEffects of hydrophobic and electrostatic interactions on the self‐assembling process of the ionic‐complementary peptide EMK16‐II are investigated by atomic force microscopy imaging, circular dichroism spectra, light scattering, and chromatography. It is found that the hydrophobicity of the peptide promotes the aggregation in pure water even at a very low concentration, resulting in a much lower critical aggregation concentration than that of another peptide, EAK16‐II. The effect of anions in solution with different valences on electrostatic interactions is also important. Monovalent anions (Cl− and Ac−) with a proper concentration can facilitate the formation of peptide fibrils, with Cl− of smaller size being more effective than Ac− of larger size. However, only small amounts of fibrils, but plenty of large amorphous aggregates, are found when the peptide solution is incubated with multivalent anions, such as SO, C6H5O, and HPO. More importantly, by gel filtration chromatography, the citrate anion, which induces a similar effect on the self‐assembling process of EMK16‐II as that of SO and HPO, can interact with two or more positively charged residues of the peptide and reside in the amorphous aggregates. This implies a “salt bridge” effect of multivalent anions on the peptide self‐assembling process, which can interpret a previous puzzle why divalent cations inhibit the formation of ordered nanofibrils of the ionic‐complementary peptides. Thus, our results clarify the important effects of hydrophobic and electrostatic interactions on the self‐assembling process of the ionic‐complementary peptides. These are greatly helpful for us to understand the mechanism of peptides' self‐assembling process and protein folding and aggregation. © 2009 Wiley Periodicals, Inc. Biopolymers 93: 318–329, 2010.This article was originally published online as an acceptedpreprint. The “Published Online” date corresponds to the preprintversion. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com