bluuebunny/crossref_metadata_2025 huggingface dataset:
Lignocellulosic Flour from Cladodes of Opuntia ficus‐indica Reinforced Poly(propylene) Composites
Authors: Malainine Mohamed E. , Mahrouz Mostafa , Dufresne Alain
Published: October 2004

Summary: A lignocellulosic flour was obtained by grinding dried cladodes of Opuntia ficus‐indica. It was used as low cost natural filler in PP and the effect of the treatment of the filler with MAPP was also investigated. The morphology and thermal properties of these composites were evaluated by SEM and DSC, respectively. MAPP coating resulted in a better adhesion between the filler and the matrix and higher homogeneity of the material. A decrease of the degree of crystallinity of the PP matrix in presence of the untreated filler was observed. Dynamic mechanical analysis and tensile properties were also studied. High‐strain tensile properties display enhanced mechanical properties for MAPP treated‐based composites only. When conditioned in highly moist atmosphere (98% RH), both the water uptake and water diffusion coefficient decrease when the filler was treated. These effects were ascribed to the promoting interfacial adhesion induced by the coating treatment. In liquid water, this increased adhesion between the filler and the matrix results in a higher weight loss of the material. It is due to the removal of the grafted polymer from the material during the dissolution of part of the filler.

SEMs of freshly fractured surface for a PP film filled with 10 wt.‐% of MAPP treated OFI cladode (top) and calcium oxalate crystallite within the PP matrix for a 3 wt.‐% filled composite (bottom).

magnified image

SEMs of freshly fractured surface for a PP film filled with 10 wt.‐% of MAPP treated OFI cladode (top) and calcium oxalate crystallite within the PP matrix for a 3 wt.‐% filled composite (bottom).
End‐Grained Wood‐Polyurethane Composites, 1
Authors: Persenaire Olivier , Alexandre Michaël , Degée Philippe , Pirard René , Dubois Philippe
Published: October 2004

Summary: In order to improve the dimensional stability of end‐grained wood upon environmental humidity variations, a two‐step procedure was thoroughly studied which involved the osmotic impregnation of native poplar wood by PEG, followed by the reactive impregnation with HMDI, leading to polymer chain extension and polyurethane formation. It came out that the efficiency of PEG and/or polyurethane grafting within ligno‐cellulosic cell walls was intimately related to parameters such as concentration of the PEG impregnation bath, PEG molar mass, time and temperature of impregnation steps. Based on the different sample characterizations, Soxhlet extraction and density measurements, it came out that adequate experimental conditions are to carry out osmotic impregnation at 20 °C for 24 h starting from an aqueous solution of PEG ([PEG] = 0.5 mol · L−1 and $\overline M _{{\rm n}\,{\rm PEG}}$ = 400 or 1 000) and reactive impregnation in bulk with a large excess of HMDI at 20 °C for 2 h. Combining scanning electron microscopy and mercury porosimetry demonstrated the selective impregnation of cell wall and wood rays which were collapsed in native wood and expanded in wood polyurethane composites.

SEM of an end‐grained wood transversal cross‐section after Soxhlet extractions successively with water and THF.

magnified image

SEM of an end‐grained wood transversal cross‐section after Soxhlet extractions successively with water and THF.
End‐Grained Wood‐Polyurethane Composites, 2
Authors: Persenaire Olivier , Alexandre Michaël , Degée Philippe , Dubois Philippe
Published: October 2004

Summary: This paper is the second of a two‐part series devoted to the preparation and the characterization of end‐grained WPCs. WPCs were obtained by polycondensation and reactive grafting of PEG or PPG with diisocyanate derivatives within the wood structure. In this part of the study, the improvement of both the dimensional stability and mechanical properties were investigated. It came out that dimensional stability was influenced by the polyol nature, functionality, and content in wood. Both PEG and PPG appeared to be efficient to improve dimensional stabilization, especially at higher weight fraction in wood. A tuning of the impregnation conditions allowed to reach a dimensional stabilization as high as 70%. Performing compression and bending tests evidenced that the mechanical properties of the WPCs were not negatively affected by the reactive impregnation process. Moreover, it could be shown that the WPCs prepared starting from PPG displayed higher stiffness than PEG‐based WPCs.

Schematic representation of the three‐layered wood cell wall.

magnified image

Schematic representation of the three‐layered wood cell wall.
The Effect of Particle Matrix Adhesion on the Mechanical Properties of Silica Filled Cyanate Ester Composites
Authors: Wooster Tim J. , Abrol Simmi , Hey Jeffrey M. , MacFarlane Douglas R.
Published: October 2004

Summary: The effect of silica and its surface treatment on the mechanical properties of composites was studied as part of the evaluation of cyanate ester matrices as potential electronic encapsulants. Three filler surface treatments were used, as a qualitative interfacial adhesion scale, in an attempt to gauge the magnitude of interfacial adhesion between untreated filler and the cyanate ester matrix. There was strong interfacial adhesion between matrix and untreated filler. The level of silica content most affected composite modulus and fracture toughness. Filler surface treatment most affected composite strength and fracture toughness/energy. Composite fracture was found to occur via crack pinning and/or crack blunting depending on the strength of adhesion. The composites evaluated were found to possess suitable mechanical properties for potential use as electronic encapsulants.

magnified image
An Improved Method for the Dispersion Assessment of Flame Retardant Filler/Polymer Systems Based on the Multifractal Analysis of SEM Images
Authors: Mills Stephen L. , Lees Graham C. , Liauw Christopher M. , Lynch Stephen
Published: October 2004

Summary: The dispersion quality of filler particles in highly loaded, flame retardant filled (FRF) polymer composites has been quantified using a complementary multifractal image analysis method. The use of an alternative imaging signal, backscattered electrons, greatly reduced the time required for image capture, relative to energy dispersive X‐ray signals discussed previously. Characteristic Dq multifractal spectra were calculated from BSE image data and multifractal curve width was once again observed to be a good indicator of dispersion quality. Numerically derived data was in strong agreement with a visual interpretation of images exhibiting variations in dispersion quality. This new method was used to study a series of FRF/EVA composite compounds based on aluminium hydroxide and magnesium hydroxide, both uncoated and coated with isostearic acid. Results from a screening experimental design were used to investigate the effect of material formulation on dispersion quality. Variations in dispersion quality observed in formulations based on isostearic acid treated filler could be related to the differing isostearic acid adsorption characteristics of the two metal hydroxides.

Observed versus predicted scatter plot for the linear model describing the dependence of mean Dq curve width on material formulation.

magnified image

Observed versus predicted scatter plot for the linear model describing the dependence of mean Dq curve width on material formulation.
Synthesis and Characterization of Hyperbranched Poly(β‐ketoester) by the Michael Addition
Authors: Kim Yang‐Bae , Kim Hyun Kyoung , Nishida Haruo , Endo Takeshi
Published: October 2004

Summary: A novel hyperbranched poly(β‐ketoester) was synthesized from 2‐(acetoacetoxy)ethyl acrylate by the Michael addition in the presence of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) as catalyst. 1H NMR integration experiments revealed that the degree of branching in the poly(β‐ketoester) was remarkably high at a level of 82.9%. The number‐average molecular weight of the polymer was between 2 100 and 12 000 and increased with reaction temperature and conversion.

Synthesis of hyperbranched polymer by Michael addition of AAEA.

magnified image

Synthesis of hyperbranched polymer by Michael addition of AAEA.
Cover Picture: Macromol. Mater. Eng. 10/2004
Authors: Mills Stephen L. , Lees Graham C. , Liauw Christopher M. , Lynch Stephen
Published: October 2004

Cover: Back scattered electron SEM images of cryo‐cut surfaces of a composites of magnesium hydroxide and ethylene vinyl acetate. The images show the effect of filler content on dispersion quality. The graph quantifies the dispersion quality via Dq multi‐fractal spectra, the poorer the dispersion the greater the deflection of the curve downwards. This deflection is quantified as a Dq spectral width. At low filler level (Images 2–4), the shear stress developed in the melt during processing is insufficient to break up agglomerates.

Further details can be found in the Full Paper by S. L. Mills, G. C. Lees, C. M. Liauw,* and S. Lynch on page 864.
Light‐Induced Demixing of Hole or Electron Transporting Moieties
Authors: Behl Marc , Zentel Rudolf , Broer Dick J.
Published: October 2004

Summary: This paper describes the synthesis of two triphenylamine monomers (hole conducting) and one triazine monomer (electron conducting) which differ in their copolymerization parameters because of their styrene and vinyl ester nature. A blend of triphenylamine monomer and poly(ethylene glycol) and mixtures of both types of monomers (triphenylamine and triazine) were illuminated through a line mask, creating laterally modulated radicals, thus leading to lateral demixing. The experiments with mixtures of triphenylamine and triazine monomers show that the concentration of p‐ or n‐type polymers can be modulated laterally in a controlled way.

AFM measurement of line pattern formed by illuminating a mixture of monomer 2 and 3 showing the height difference between illuminated and non‐illuminated areas.

image

AFM measurement of line pattern formed by illuminating a mixture of monomer 2 and 3 showing the height difference between illuminated and non‐illuminated areas.
Reversible pH‐Dependent Properties of Multilayer Microcapsules Made of Weak Polyelectrolytes
Authors: Mauser Tatjana , Déjugnat Christophe , Sukhorukov Gleb B.
Published: October 2004

Summary: We investigated microcapsules composed of the weak polyelectrolytes poly(allylamine hydrochloride) (PAH) and poly(methacrylic acid) (PMA) assembled on calcium carbonate cores. These capsules are stable in the pH range from 2.5 to 11.5, undergoing reversible swelling in the pH interval from 2.7 to 2.6. Capsule swelling occurs at a protonation degree above 90%. The pH‐dependent size variation of PAH/PMA capsules is blocked after crosslinking of the polyelectrolyte layers.

Schematic of the swelling and de‐swelling of the capsules with changing pH.

image

Schematic of the swelling and de‐swelling of the capsules with changing pH.
Five‐year follow‐up study of hyperechogenicity of the substantia nigra in Parkinson's disease
Authors: Berg Daniela , Merz Berthold , Reiners Karlheinz , Naumann Markus , Becker Georg
Published: October 2004

Using transcranial sonography, an area of hyperechogenicity at the substantia nigra (SN) may be detected as a typical marker in patients with Parkinson's disease (PD) as well as in approximately 9% of healthy subjects vulnerable to nigrostriatal impairment. In this longitudinal study, we provide evidence that the area of SN hyperechogenicity does not change in the course of PD. In conjunction with earlier findings in children and adolescents, this evidence indicates that, from late adolescence onward, this ultrasound finding is a trait marker for nigrostriatal vulnerability. © 2004 Movement Disorder Society
Limit analysis method in elastostatics and electrostatics
Authors: Brigadnov Igor A.
Published: October 2004

The limit analysis method for an estimation of mechanical and electrical strength safety conditions for non‐linear elastic and dielectric solids, respectively, is examined. By the variational method and the duality theory, the appropriate initial and dual limit analysis problems (LAPs) are formulated. It is demonstrated that the initial LAPs need a relaxation, but the appropriate fully relaxed problems have no clear physical interpretation. On the other hand, the dual LAPs have a clear physical interpretation. The general initial and dual LAPs for quasi‐static problems of Continuum Mechanics are formulated. The appropriate 2‐D finite‐element approximations and numerical solutions are presented. Copyright © 2004 John Wiley & Sons, Ltd.
1H NMR spectroscopic criteria for the configuration of N‐acyl‐α,β‐dehydro‐α‐amino acid esters
Authors: Mazurkiewicz Roman , Kuźnik Anna , Grymel Mirosława , Kuźnik Nikodem
Published: October 2004

The diagnostic values of the following three spectral criteria for the configuration of N‐acyl‐α,β‐dehydro‐α‐amino acid esters were examined: (i) the proton at the β‐position at the double bond of a Z‐isomer is shielded if compared with the respective E‐isomer $(\delta_{\beta}^{Z} \langle \delta_{\beta}^{E})$; (ii) the proton at the nitrogen atom is shielded in a Z‐isomer in comparison with the corresponding E‐isomer $(\delta_{\rm NH}^{Z} \langle \delta_{\rm NH}^{E})$; and (iii) changing of the solvent from CDCl3 to deuterated trifluoroacetic acid (TFA) causes shielding of the Hβ vinylic proton of an E‐isomer or deshielding of the respective proton of the Z‐isomer ($\delta_{{\rm CDCl}_{3}}^{E} \rangle \delta_{\rm TFA}^{E}$ or $\delta_{{\rm CDCl}_{3}}^{Z} \langle \delta_{\rm TFA}^{Z}$). The investigations were based on a set of 22 (Z)‐ and (E)‐N‐acyl‐α,β‐dehydro‐α‐amino acid esters of diverse structures, with aliphatic, aromatic and heteroaromatic substituents at the vinylic β‐carbon; most of the examined compounds were hitherto unknown. The application of the substituent effect additivity rule given by Pascual et al. for olefinic protons leads to evidently erroneous configuration assignments of N‐acyl‐α,β‐dehydro‐α‐amino acid esters. The considered criteria were fulfilled for all the examined cases with one exception [the second criterion for the α‐pivaloylamino‐β‐(2‐furyl)acrylates]. The comparison of changes in the chemical shifts of Hβ vinylic protons in CDCl3 and deuterated TFA seems to be the most reliable and useful configuration criterion, as it can be used in the case of a single isomer. Copyright © 2004 John Wiley & Sons, Ltd.
Amyloid myopathy: Characteristic features of a still underdiagnosed disease
Authors: Chapin John E. , Kornfeld Mario , Harris Alexis
Published: October 2004

A 62‐year‐old man with progressive proximal weakness underwent extensive evaluation including muscle biopsy without a clear diagnosis being established. A repeat muscle biopsy including Congo red–stained sections revealed infiltration of blood‐vessel walls and endomysium with amyloid protein, as well as an unusual pattern of pathologic changes to muscle fibers. From a review of 79 cases of amyloid myopathy reported in the English‐language literature, the characteristic features of this disorder are described. Congo red–stained sections of muscle biopsy viewed under fluorescent or polarized optics, and serum or urine protein immunoelectrophoresis, play an important role in the evaluation of myopathy. Amyloid myopathy should be a consideration in adults with progressive neuromuscular weakness of uncertain cause. Muscle Nerve, 2004
Synaptic vesicle cycling at type‐identified diaphragm neuromuscular junctions
Authors: Mantilla Carlos B. , Rowley Katharine L. , Fahim Mohamed A. , Zhan Wen‐Zhi , Sieck Gary C.
Published: October 2004

Differences in neuromuscular transmission and neuromuscular junction morphology exist across muscle fiber types. We hypothesized that these fiber‐type differences are reflected in the size of the cycling synaptic vesicle pool. Synaptic vesicle cycling at type‐identified rat diaphragm neuromuscular junctions was examined by fluorescently labeling presynaptic vesicles with FM4‐64. We found that FM4‐64 fluorescence uptake was higher at presynaptic terminals of type I/IIa fibers than type IIx/IIb fibers. However, no fiber‐type differences in the rate of FM4‐64 destaining were found with repetitive nerve stimulation. Synaptic vesicle density at active zones was examined by transmission electron microscopy. In accordance with FM4‐64 uptake, synaptic vesicle density was greater at type I/IIa than IIx/IIb fibers. These results demonstrate differences in synaptic vesicle cycling across diaphragm muscle fiber types, which may underlie previously observed differences in neuromuscular transmission across diaphragm muscle fiber types. In the diaphragm, motor units comprising type I and type IIa fibers are most frequently recruited with a duty cycle of ∼40%. Motor units comprising IIx/IIb fibers are infrequently recruited and only for short durations. The capacity for synaptic vesicle release and cycling at different muscle fiber types matches the functional requirements of these motor units. If the demand for recruitment of motor units comprising IIx/IIb fibers increases, for example, with mechanical loading, there is an increased risk for neuromuscular transmission failure that my relate to the capacity for synaptic vesicle release and cycling. Muscle fiber type–specific adaptations should be considered when examining neuromuscular disorders. Muscle Nerve, 2004
On d‐threshold graphs and d‐dimensional bin packing
Authors: Caprara Alberto , Lodi Andrea , Rizzi Romeo
Published: October 2004

We illustrate efficient algorithms to find a maximum stable set and a maximum matching in a graph with n nodes given by the edge union of d threshold graphs on the same node set, in case the d graphs in the union are known. Actually, because the edge set of a threshold graph can be implicitly represented by assigning values to the nodes, we assume that we know these values for each of the d graphs in the union. We present an O(n log n + nd−1) time algorithm to find a maximum stable set and an O(n2) time algorithm to find a maximum matching, in case d is constant. For the case d = 2, the running time of the latter is reduced to O(n log n) provided an additional technical condition is satisfied. The natural application of our results is the fast computation of lower bounds for the d‐dimensional bin packing problem, for which the compatibility relations between items are represented by the edge union of d threshold graphs with one node for each item, the value of the node for the i‐th graph being equal to the size of the item on the i‐th dimension. © 2004 Wiley Periodicals, Inc. NETWORKS, Vol. 44(4), 266–280 2004
The Push Tree problem
Authors: Havet Frédéric , Wennink Marc
Published: October 2004

In this article, we introduce the Push Tree problem, which exposes the tradeoffs between the use of push and pull mechanisms in information distribution systems. One of the interesting features of the Push Tree problem is that it provides a smooth transition between the minimum Steiner Tree and the Shortest Path problems. We present initial complexity results and analyze heuristics. Moreover, we discuss what lessons can be learned from the static and deterministic Push Tree problem for more realistic scenarios characterized by high uncertainty and changing information request and update patterns. © 2004 Wiley Periodicals, Inc. NETWORKS, Vol. 44(4), 281–291 2004
Solving quadratic matrix equations and factoring polynomials: new fixed point iterations based on Schur complements of Toeplitz matrices
Authors: Bini Dario A. , Gemignani Luca
Published: October 2004

A new class of functional iterations is introduced for the numerical solution of the matrix equation C+AX+BX2=0 where A,B,C are given m × m matrices and X is the unknown matrix. Each iteration in this class is globally convergent, self‐correcting, and the local convergence is linear with an arbitrarily large speed. The new iterations, which rely on the properties of Schur complements of block tridiagonal block Toeplitz matrices, overcome the problems encountered by quadratically convergent methods, like cyclic reduction, in the case of numerical singularity situations. Copyright © 2004 John Wiley & Sons, Ltd.
Two‐step waveform relaxation methods for implicit linear initial value problems
Authors: Pan Jian‐Yu , Bai Zhong‐Zhi , Ng Michael K.
Published: October 2004

A class of two‐step waveform relaxation methods is established and studied for solving implicit linear initial value problems, which, in particular, includes the alternating direction implicit waveform relaxation (ADIWR) methods. The convergence property of the ADIWR methods is studied in depth under suitable conditions, and their computing behaviour is illustrated by numerical examples. Moreover, we discuss about the choice of the optimal parameters involved in the ADIWR methods. Copyright © 2004 John Wiley & Sons, Ltd.
A posteriori finite element bounds to linear functional outputs of the three‐dimensional Navier–Stokes equations
Authors: Cheng Zhong , Paraschivoiu Marius
Published: October 2004

An implicit a posteriori finite element error estimation method is presented to inexpensively calculate lower and upper bounds for a linear functional output of the numerical solutions to the three‐dimensional Navier–Stokes (N–S) equations. The novelty of this research is to utilize an augmented Lagrangian based on a coarse mesh linearization of the N–S equations and the finite element tearing and interconnecting (FETI) procedure. The latter approach extends the a posteriori bound method to the three‐dimensional Crouzeix–Raviart space for N–S problems. The computational advantage of the bound procedure is that a single coupled non‐symmetric large problem can be decomposed into several uncoupled symmetric small problems. A simple model problem, which is selected here to illustrate the procedure, is to find the lower and upper bounds of the average velocity of a pressure driven, incompressible, steady Newtonian fluid flow moving at low Reynolds numbers through an endless square channel which has an array of rectangular obstacles. Numerical results show that the bounds for this output are rigorous, i.e. always in the asymptotic certainty regime, that they are sharp and that the required computational resources decrease significantly. Parallel implementation on a Beowulf cluster is also reported. Copyright © 2004 John Wiley & Sons, Ltd.
Fast and accurate 4‐node quadrilateral
Authors: Fredriksson Magnus , Ottosen Niels Saabye
Published: October 2004

An accurate and variationally consistent 4‐node quadrilateral element is introduced where high coarse mesh accuracy and low mesh distortion sensitivity are characteristic qualities, even when incompressibility is approached for plane strain. One‐point quadrature integration procedure is adopted and a new improved stabilization technique is developed. Orthogonality conditions are utilized so that the patch test is satisfied for arbitrary quadrilaterals. Several numerical examples including a convergence rate study are presented which confirm the excellent performance of this element. Copyright © 2004 John Wiley & Sons, Ltd.
A generalized dimension‐reduction method for multidimensional integration in stochastic mechanics
Authors: Xu H. , Rahman S.
Published: October 2004

A new, generalized, multivariate dimension‐reduction method is presented for calculating statistical moments of the response of mechanical systems subject to uncertainties in loads, material properties, and geometry. The method involves an additive decomposition of an N‐dimensional response function into at most S‐dimensional functions, where S≪N; an approximation of response moments by moments of input random variables; and a moment‐based quadrature rule for numerical integration. A new theorem is presented, which provides a convenient means to represent the Taylor series up to a specific dimension without involving any partial derivatives. A complete proof of the theorem is given using two lemmas, also proved in this paper. The proposed method requires neither the calculation of partial derivatives of response, as in commonly used Taylor expansion/perturbation methods, nor the inversion of random matrices, as in the Neumann expansion method. Eight numerical examples involving elementary mathematical functions and solid‐mechanics problems illustrate the proposed method. Results indicate that the multivariate dimension‐reduction method generates convergent solutions and provides more accurate estimates of statistical moments or multidimensional integration than existing methods, such as first‐ and second‐order Taylor expansion methods, statistically equivalent solutions, quasi‐Monte Carlo simulation, and the fully symmetric interpolatory rule. While the accuracy of the dimension‐reduction method is comparable to that of the fourth‐order Neumann expansion method, a comparison of CPU time suggests that the former is computationally far more efficient than the latter. Copyright © 2004 John Wiley & Sons, Ltd.
Preparation and properties of composites made from rice straw and poly(vinyl chloride) (PVC)
Authors: Kamel Samir
Published: October 2004

Rice straw was employed for the preparation of lignocellulosic‐poly(vinyl chloride) (PVC) composites. The effect of pretreatment of rice straw, concentration of PVC, pressure as well as pressing temperature on the mechanical properties and water absorption was studied. Also, the effect of lignin as coupling agent on the mechanical properties and water absorption of composite was studied. Composites of rice straw comprising both PVC and a coupling agent offer superior properties compared to those made from only rice straw and PVC. The extent of improvement in the mechanical properties and dimensional stability of composites depended not only on the pretreatment of rice straw, concentration of PVC and lignin but also on pressure and pressing temperature. Copyright © 2004 John Wiley & Sons, Ltd.
“Living” radical graft polymerization of styrene to styrene butadiene rubber (SBR) with 2,2,6,6‐tetramethyl‐1‐piperidinyloxy (TEMPO)
Authors: Abbasian Mojtaba , Namazi Hassan , Entezami Ali Akbar
Published: October 2004

Well‐defined graft copolymers with styrene butadiene rubber (SBR) backbones and polystyrene branches were synthesized by living free radical polymerization (LFRP) techniques. Thus 1‐ benzoyl‐2‐phenyl‐2‐(2′,2′,6′,6′‐tetramethyl‐piperidinyl‐1′‐oxy)ethane (BZ‐TEMPO) was synthesized and hydrolyzed to the corresponding 1‐hydroxyl derivative. This functional nitroxyl compound was coupled with brominated SBR (SBR‐Br). The resulting macroinitiator (SBR‐TEMPO) for “living” free radical polymerization was then heated in the presence of styrene for the formation of the controlled graft copolymer. 1H‐NMR and IR spectroscopy were used to investigate the structure of the polymers. Copyright © 2004 John Wiley & Sons, Ltd.
Low loss second‐order non‐linear optical crosslinked polymers based on a phosphorus‐containing maleimide
Authors: Chen Chih‐Ping , Huang Gwo‐Su , Jeng Ru‐Jong , Chou Che‐Chung , Su Wen‐Chiung , Chang Huey‐Ling
Published: October 2004

A series of crossslinked organic and organic/inorganic polymers based on maleimide chemistry have been investigated for second‐order non‐linear optical (NLO) materials with excellent thermal stability and low optical loss. Two reactive chromophores (maleimide‐containing azobenzene dye and alkoxysilane‐containing azobenzene dye) were incorporated into a phosphorus‐containing maleimide polymer, respectively. The selection of the phosphorus‐containing maleimide polymer as the polymeric matrices provides enhanced solubility and thermal stability, and excellent optical quality. Moreover, a full interpenetrating network (IPN) was formed through simultaneous addition reaction of the phosphorus‐containing maleimide, and sol‐gel process of alkoxysilane dye (ASD). Atomic force microscopy (AFM) results indicate that the inorganic networks are distributed uniformly throughout the polymer matrices on a nano‐scale. The silica particle sizes are well under 100 nm. Using in situ contact poling, the r33 coefficients of 2.2–17.0 pm/V have been obtained for the optically clear phosphorus‐containing NLO materials. Excellent temporal stability (100°C) and low optical loss (0.99–1.71 dB/cm; 830 nm) were also obtained for these phosphorus‐containing materials. Copyright © 2004 John Wiley & Sons, Ltd.
Poly(caprolactone triol) as plasticizer agent for cellulose acetate films: influence of the preparation procedure and plasticizer content on the physico‐chemical properties
Authors: Meier Marcia M. , Kanis Luiz A. , de Lima João C. , Pires Alfredo T. N. , Soldi Valdir
Published: October 2004

The influence of the plasticizer content and film preparation procedure on the morphology, density, thermal and mechanical properties of cellulose acetate (CA) films plasticized with poly‐(caprolactone triol) (PCL‐T), were studied. Differential scanning calorimetry (DSC), thermal mechanical analysis (TMA), scanning electron microscopy (SEM), wide‐angle X‐ray diffraction (WAXD) and infrared spectroscopy (FT‐IR) techniques were used. The films were prepared by dry‐casting CA and CA/PCL‐T in acetone or acetone/water solutions, which produced transparent and opaque films, respectively. In contrast to the transparent films, which were dense, the opaque films presented a porous morphology. However, the presence of PCL‐T reduced the opaque film porosity, increasing, in consequence, its bulk density. The TMA results revealed that PCL‐T reduced the glass transition temperature more significantly in the transparent than in opaque films. Only the transparent CA/PCL‐T films presented a melting temperature, that reduced with higher concentrations of PCL‐T, suggesting a higher ordering (crystallinity) when the films were prepared in the absence of water, as observed from WAXD curves. The mechanical properties also showed that the transparent films were more soft and tough than the opaque films. In summary, PCL‐T was a good plasticizer agent for CA films due to the presence of hydrogen bonds between the components (FT‐IR spectra). The presence of water in the dry casting process has a significant effect mainly on film morphology and mechanical properties. Copyright © 2004 John Wiley & Sons, Ltd.
Influence of gamma irradiation on high density polyethylene/ethylene‐vinyl acetate/clay nanocomposites
Authors: Lu Hongdian , Hu Yuan , Kong Qinghong , Cai Yibing , Chen Zuyao , Fan Weicheng
Published: October 2004

The study of high density polyethylene (HDPE)/ethylene‐vinyl acetate (EVA)/and organically‐modified montmorillonite (OMT) nanocomposites prepared by melt intercalation followed by exposure to gamma‐rays have been carried out. The morphology and properties of the nanocomposites were studied using X‐ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and cone calorimetry. The purpose of the study focuses on the influence of gamma irradiation on the morphology, thermal stability and flammability properties of the nanocomposites. XRD studies and TEM images verified that the ordered intercalated nanomorphology of the nanocomposites was not disturbed by gamma irradiation. TGA data showed that the nano‐dispersion of clay throughout the polymer inhibited the irradiation degradation of HDPE/EVA blend, which led to the nanocomposites exhibiting superior irradiation‐resistant properties than that of the pure blend. Cone calorimetry results indicated that the improvement in heat release rate (HRR) for irradiated HDPE/EVA blend was suppressed efficiently when clay was present. Increasing clay loading from 2 to 10% was beneficial by improving the flammability properties of the nanocomposites, but promoted a rapid increase in the sub‐peak HRR at high irradiation dose level. Copyright © 2004 John Wiley & Sons, Ltd.
Toughening of cyanate ester resin by carboxyl terminated nitrile rubber
Authors: Feng Yu , Fang Zhengping , Gu Aijuan
Published: October 2004

The carboxyl terminated butadiene‐acrylonitrile (CTBN) rubber was used to improve the toughness of the cyanate ester (CE) resin. The toughness of the modified blends depended on the CTBN content. The addition of 10 phr (g/100gCE) CTBN in CE resin led to a 200% increase in the impact strength with a loss of storage modulus. The transmission electron microscopy result showed the existence of rubber particles, inferring that phase separation had occured after curing. The thermogravimetric analysis curve of CTBN indicated the presence of cavities which also can be observed on the fractured surface in the scanning electron microscopy pictures using high magnification. Thus, phase‐separation and cavities toughening mechanisms function together to improve the toughness. Copyright © 2004 John Wiley & Sons, Ltd.
ProteomeGRID: towards a high‐throughput proteomics pipeline through opportunistic cluster image computing for two‐dimensional gel electrophoresis
Authors: Dowsey Andrew W. , Dunn Michael J. , Yang Guang‐Zhong
Published: October 2004

The quest for high‐throughput proteomics has revealed a number of critical issues. Whilst improved two‐dimensional gel electrophoresis (2‐DE) sample preparation, staining and imaging issues are being actively pursued by industry, reliable high‐throughput spot matching and quantification remains a significant bottleneck in the bioinformatics pipeline, thus restricting the flow of data to mass spectrometry through robotic spot excision and protein digestion. To this end, it is important to establish a full multi‐site Grid infrastructure for the processing, archival, standardisation and retrieval of proteomic data and metadata. Particular emphasis needs to be placed on large‐scale image mining and statistical cross‐validation for reliable, fully automated differential expression analysis, and the development of a statistical 2‐DE object model and ontology that underpins the emerging HUPO PSI GPS (Human Proteome Organization Proteomics Standards Initiative General Proteomics Standards. The first step towards this goal is to overcome the computational and communications burden entailed by the image analysis of 2‐DE gels with Grid enabled cluster computing. This paper presents the proTurbo framework as part of the ProteomeGRID, which utilises Condor cluster management combined with CORBA communications and JPEG‐LS lossless image compression for task farming. A novel probabilistic eager scheduler has been developed to minimise make‐span, where tasks are duplicated in response to the likelihood of the Condor machines' owners evicting them. A 60 gel experiment was pair‐wise image registered (3540 tasks) on a 40 machine Linux cluster. Real‐world performance and network overhead was gauged, and Poisson distributed worker evictions were simulated. Our results show a 4:1 lossless and 9:1 near lossless image compression ratio and so network overhead did not affect other users. With 40 workers a 32× speed‐up was seen (80% resource efficiency), and the eager scheduler reduced the impact of evictions by 58%.
Proteomic analysis of melanoma‐derived exosomes by two‐dimensional polyacrylamide gel electrophoresis and mass spectrometry
Authors: Mears Rainy , Craven Rachel A. , Hanrahan Sarah , Totty Nick , Upton Carol , Young Sarah L. , Patel Poulam , Selby Peter J. , Banks Rosamonde E.
Published: October 2004

Exosomes are 40–100 nm vesicles released by numerous cell types and are thought to have a variety of roles depending on their origin. Exosomes derived from antigen presenting cells have been shown to be capable of initiating immune responses in vivo and eradicating established tumours in murine models. Tumour‐derived exosomes can be utilised as a source of tumour antigen for cross‐priming to T‐cells and are thus of interest for use in anti‐tumour immunotherapy. Further exploration into the protein composition of exosomes may increase our understanding of their potential roles in vivo and this study has examined the proteome of exosomes purified from cell supernatants of the melanoma cell lines MeWo and SK‐MEL‐28. The vesicular nature and size (30–100 nm) of the purified exosomes was confirmed by electron microscopy and sucrose density gradient centrifugation. Western blotting demonstrated the absence of calnexin and cytochrome c, verifying the purity of the exosome preparations, as well as enrichment of MHC class I and the tumour‐associated antigens Mart‐1 and Mel‐CAM. The two‐dimensional polyarcylamide gel electrophoresis (2‐D PAGE) protein profiles of exosomes from the two cell lines were highly comparable and strikingly different from the profiles of the total cell lysates. Mass spectrometric sequencing identified proteins present in 49 protein spots in the exosome lysates. Several of these have been identified previously in exosomes but some are novel, including p120 catenin, radixin, and immunoglobulin superfamily member 8 (PGRL). Proteins present in whole‐cell lysates that were significantly reduced or excluded from exosomes were also identified and included several mitochondrial and lysosomal proteins, again confirming the proposed endosomal origin of exosomes. This study presents a starting point for future more in‐depth protein studies of tumour‐derived exosomes which will aid the understanding of their biogenesis and targeting for use in anti‐tumour immunotherapy protocols.
Proteomic analysis of the response of Arabidopsis chloroplast proteins to high light stress
Authors: Phee Bong‐Kwan , Cho Jin‐Hwan , Park Sebyul , Jung Jin Hee , Lee Youn‐Hyung , Jeon Jong‐Seong , Bhoo Seong Hee , Hahn Tae‐Ryong
Published: October 2004

Light is an essential environmental factor in the progression of plant growth and development but prolonged exposure to high levels of light stress can cause cellular damage and ultimately result in the death of the plant. Plants can respond defensively to this stress for a limited period and this involves changes to their gene expression profiles. Proteomic approaches were therefore applied to the study of the response to high light stress in the Arabidopsis thaliana plant species. Wild‐type Arabidopsis was grown under normal light (100 μmol photons·m−2·s−1) conditions and then subjected to high light (1000 μmol photons·m−2·s−1) stress. Chloroplasts were then isolated from these plants and both soluble and insoluble proteins were extracted and subjected to two‐dimensional (2‐D) gel electrophoresis. The resolved proteins were subsequently identified by matrix assisted laser desorption/ionization‐time of flight‐mass spectrometry (MALDI‐TOF‐MS) and comparative database analysis. 64 protein spots, which were identified as candidate factors that responded to high light stress, were then selected for analysis and 52 of these were successfully identified using MALDI‐TOF‐MS analysis. 35 of the 52 identified proteins were found to decrease their expression levels during high light stress and a further 14 of the candidate proteins had upregulated expression levels under these conditions. Most of the proteins that were downregulated during high light stress are involved in photosynthesis pathways. However, many of the 14 upregulated proteins were identified as previously well‐known high light stress‐related proteins, such as heat shock proteins (HSPs), dehydroascorbate reductase (DHAR), and superoxide dismutase (SOD). Three novel proteins that were more highly expressed during periods of high light stress but had no clear functional relationship to these conditions, were also identified in this study.
Proteomic analysis of pathogen‐responsive proteins from rice leaves induced by rice blast fungus,Magnaporthe grisea
Authors: Kim Sun Tae , Kim Sang Gon , Hwang Du Hyeon , Kang Sun Young , Kim Han Ju , Lee Byung Hyun , Lee Jeung Joo , Kang Kyu Young
Published: October 2004

Proteomic approaches using two‐dimensional gel electrophoresis (2‐DE) were adopted to identify proteins from rice leaf that are differentially expressed in response to the rice blast fungus,Magnaporthe grisea. Microscopic observation of inoculated leaf withM. grisearevealed that callose deposition and hypersensitive response was clearly visible in incompatible interactions but excessive invading hypha with branches were evident in compatible interactions. Proteins were extracted from leaves 24, 48, and 72 hours after rice blast fungus inoculation. Eight proteins resolved on the 2‐DE gels were induced or increased in the inoculated leaf. Matrix‐assisted laser desorption/ionization‐time of flight analysis of these differentially displayed proteins showed them to be two receptor‐like protein kinases (RLK), two β‐1.3‐glucanases (Glu1, Glu2), thaumatin‐like protein (TLP), peroxidase (POX 22.3), probenazole‐inducible protein (PBZ1), and rice pathogenesis‐related 10 (OsPR‐10). Of these proteins, RLK, TLP, PBZ, and OsPR‐10 proteins were induced more in the incompatible interactions than in compatible ones. A phytohormone, jasmonic acid also induced all eight proteins in leaves. To confirm whether the expression profile is equal to the 2‐DE data, seven cDNA clones were used as probes in Northern hybridization experiments using total RNA from leaf tissues inoculated with incompatible and compatible rice blast fungal races. The genes encodingPOX22.3,Glu1,Glu2,TLP,OsRLK,PBZ1, andOsPR‐10 were activated in inoculated leaves, withTLP,OsRLK,PBZ1, andOsPR‐10 being expressed earlier and more in incompatible than in compatible interactions. These results suggest that early and high induction of these genes may provide host plants with leading edges to defend themselves. The localization of two rice PR‐10 proteins, PBZ1 and OsPR‐10, was further examined by immunohistochemical analysis. PBZ1 accumulated highly in mesophyll cells under the attachment site of the appressorium. In contrast, OsPR‐10 expression was mainly localized to vascular tissue.
Polymerization in magnetic field. XVI. Kinetic aspects regarding methyl methacrylate polymerization in high magnetic field
Authors: Chiriac Aurica P.
Published: October 2004

The effect of a high magnetic field of 7 T in the reaction of methyl methacrylate polymerization is emphasized. The intervening magnetokinetic modifications are correlated with the system of radical initiation with benzoyl peroxide, 2,2′‐azobis(2‐methylpropionitrile), 4,4′‐azobis(4‐cyanopentanoic acid), and 1,1′‐azobis(cyclohexane‐1‐carbonitrile). The characterization of the synthesized polymers is correlated with the reaction conditions. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5678–5686, 2004
Preparation and characterization of acrylic‐based black particles of poly(methyl methacrylate‐co‐ethylene glycol dimethacrylate) by dispersion polymerization for electrophoretic displays
Authors: Yu Dong‐Guk , An Jeong Ho
Published: October 2004

Ultrafine black particles, ranging in diameter from 1 to 3 μm, were prepared by dispersion polymerization in a methanol/water mixture with vinyl monomers, nonpolymerizable Sudan black B dyes, and fluorescein isothiocyanate labeled charge control additives. Both the ratio of the methanol to the water dispersion medium and the polymeric stabilizer concentration had significant effects on the particle size. The important role of the stabilizer concentration lay in the particle formation step, during which it determined the particle stability and final particle size. These could affect the extent of the aggregation of nuclei by changing the adsorption rate of the stabilizer and the viscosity of the dispersion medium, resulting in smaller particles. The fluorescent‐labeled charge control additives strongly affected the electrophoretic mobility. A small concentration of fluorescent‐labeled charge control additives increased the electrophoretic mobility. However, a further addition reduced the electrophoretic mobility of the polymer particles. The concentration dependence of the fluorescent‐labeled charge control additives on the deposition behavior in the polymer particles was successfully imaged and thereafter quantified by image analysis. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5608–5616, 2004
Free‐radical polymerization of methyl methacrylate with a tetrafunctional peroxide initiator
Authors: Scorah M. J. , Dhib R. , Penlidis A.
Published: October 2004

This study examined the use of a new tetrafunctional peroxide initiator in the bulk free‐radical polymerization of methyl methacrylate. The objective was to investigate the effect of using a multifunctional initiator through an examination of the rates of polymerization and the polymer properties. The molecular weights and radii of gyration were obtained with a size exclusion chromatograph equipped with an online multi‐angle laser light scattering detector. The performance of the tetrafunctional initiator was compared to that of a monofunctional counterpart [tert‐butylperoxy 2‐ethylhexyl carbonate (TBEC)]. The results showed that the new tetrafunctional peroxide initiator produced a faster rate of polymerization than TBEC at an equivalent concentration but also generated a polymer of a lower molecular weight. This trend was the opposite of what was observed in a previous study with styrene. When TBEC was used at a concentration four times that of the new tetrafunctional peroxide initiator, both produced equal rates of polymerization and similar molecular weights. The degree of branching was also investigated with radius‐of‐gyration plots. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5647–5661, 2004
Synthesis and characterization of novel poly(cycloalkyl methacrylate) bearing fused‐ring structure and its copolymers
Authors: Asha S. K. , Deepthimol V. , Lekshmi M.
Published: October 2004

A new family of cycloaliphatic fused‐ring acrylic polymers based on 8‐hydroxymethyltricyclo[5.2.1.02,6]decane (TCD) has been synthesized by free‐radical polymerization. TCD‐methacrylate (TCD‐MA) was synthesized by reacting TCD with methacrylic acid in toluene via transesterification with p‐toluenesulfonic acid as a catalyst. TCDMA was polymerized in toluene with benzoyl peroxide as a free‐radical initiator at 80 °C. Copolymers were synthesized by polymerizing TCDMA with styrene and methyl methacrylate. The composition of the comonomers was varied from 0 to 100%. Homo‐ and copolymers were characterized by Fourier transform infrared (FTIR) and 13C NMR spectroscopy. Molecular weight determination by gel permeation chromatography showed that the polymers were obtained in very high molecular weights in the range of Mn > 50,000 and Mw > 80,000 with relatively low polydispersity. The composition analysis of both the copolymer series were determined by 1H NMR. The thermal properties of the homo‐ and copolymers were studied with differential scanning calorimetry and all the polymers were found to be amorphous. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5617–5626, 2004
Dithiocarbamate mediated controlled/living free radical polymerization of methyl acrylate under 60Co γ‐ray irradiation: Conjugation effect of N‐group
Authors: Hua Daoben , Bai Ruke , Lu Weiqi , Pan Caiyuan
Published: October 2004

The free radical polymerizations of methyl acrylate have been studied under γ‐ray irradiation in the presence of the dithiocarbamates with different N‐groups. The results indicate that the conjugation structure of the N‐group of dithiocarbamate plays an important role in living free radical polymerization. The polymerizations reveal good living characteristics in the presence of dithiocarbamates (benzyl 1H‐imidazole‐1‐carbodithioate, benzyl 1H‐pyrrole‐1‐carbodithioate, benzyl 1H‐indole‐1‐carbodithioate, and benzyl 9H‐carbazole‐9‐carbodithioate) with N‐aryl group. In contrast, the polymerization with benzyl N,N‐diethyldithiocarbamate cannot be controlled, and the obtained polymer has a broad molecular weight distribution or even crosslink occurs. Moreover, polymerization rate is influenced by the conjugation structure of the N‐group of dithiocarbamate, and the aromatic polycyclic structure of the N‐group leads to slow polymerization. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5670–5677, 2004