bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphology control in polysulfone‐modified epoxy resins by demixing behavior
Authors: Giannotti M. I. , Solsona M. S. , Galante M. J. , Oyanguren P. A. 
Published: April 2003

AbstractPolysulfone (PSu) was used as a modifier of epoxy/aromatic diamine formulations. Two epoxy monomers, based on diglycidyl ether of bisphenol A (DGEBA), were used. The cure agent was 4,4′‐diaminodiphenylsulfone. PSu was miscible with DGEBA, as shown by the existence of a single glass‐transition temperature within the whole composition range. The effect of PSu addition on the cure kinetics was investigated. The reaction rate of the epoxy–amine species was slightly lower in the presence of PSu. The morphology was analyzed by optical and scanning electron microscopy. A range of microstructures were obtained by control over the cure temperature, the amount of PSu incorporated, and the molecular weights of the epoxy resins. The variations in the morphology resulted from the different stages of demixing, which were arrested because of the different developments of the viscosity of the system. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 405–412, 2003
Amphiphilic styrene–acrylic acid copolymers from the free‐radical retrograde‐precipitation polymerization (FRRPP) process
Authors: Caneba Gerard T. , Zhao Yi , Dar Yadunandan 
Published: April 2003

AbstractThe free‐radical retrograde‐precipitation polymerization (or FRRPP) process, a free‐radical polymerization that occurs above the lower critical solution temperature (LCST), was extended to copolymer formation. Control over the rate of polymerization and entrapment of polymer radicals in the FRRPP process was used to generate tapered styrene–acrylic acid block copolymers. To show the effectiveness of the FRRPP process, the same procedure was used with solvents that are not LCST‐based precipitants for the polymer. Kinetic data show substantial chain termination in non‐FRRPP copolymerization systems. Molecular weight information also shows propagation control in the FRRPP system. Solubilization and emulsification studies also indicate the capability of the FRRPP system in generating a much higher proportion of amphiphilic tapered block copolymers in the solid product. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 426–431, 2003
Applications of polymeric photorefractive material to reversible data storage and information processing
Authors: Chun Hyunaee , Joo Won‐Jae , Kim Nam‐Jun , Moon In Kyu , Kim Nakjoong 
Published: April 2003

AbstractA polymeric photorefractive composite was prepared from a mixture of carbazole‐substituted polysiloxane as a photoconducting medium, 2,4,7‐trinitro‐9‐fluorenone as a photosensitizer, and 2‐{3‐[(E)‐2‐(dibutylamino)‐1‐ethenyl]‐5,5‐dimethyl‐2‐cyclohexenyliden} malononitrile as an optically nonlinear chromophore. This polymeric composite, with a thickness of 100 μm, exhibited a high diffraction efficiency of 92% at a low applied electric field of 30 V/μm, which corresponded a refractive index modulation of 3 × 10−3. Applications of this polymeric composite to reversible holographic data storage and pattern recognition were demonstrated. The three‐dimensional image was recorded on our photorefractive film at an applied field of 30 V/μm, and subsequently, a high quality image was reconstructed in a real‐time operation. Pattern recognition was successfully demonstrated based on a joint‐transform optical correlation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 368–372, 2003
Temperature and liquid crystal concentration effect on thermal conductivity of poly(styrene) dispersed 5CB liquid crystal
Authors: Boudenne Abderrahim , Khaldi Smaïn 
Published: April 2003

AbstractIn the present work, we study the thermal behavior of Polymer (Polystyrene) dispersed (4‐cyano‐4′‐pentylbiphenyl) 5CB liquid crystal film composite. A photopyroelectric device was used to study thermal conductivity at homeotropic and planar aligned of 4‐cyano‐4′‐pentylbiphenyl (5CB) liquid crystal. Thermal conductivity of polystyrene (PS) has been determined and calculated from experimental applied data reported in the literature. Thermal conductivity characteristics of the PDLC films were investigated with three prediction models as a function of both temperature and liquid crystal concentration in the polymer matrix. We particularly show the behavior of this thermal conductivity in the ON and OFF state. It was found that the difference in the film thermal conductivity ranges between 3 and 21%, depending on the ON and OFF state and the liquid crystal volume concentration. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 481–486, 2003
Biaxial orientation behavior of polystyrene: Orientation and properties
Authors: Zhang Xiaomin , Ajji Abdellah 
Published: April 2003

AbstractSquare sheets of extrusion grade polystyrene (PS) were biaxially stretched using a laboratory biaxial stretcher. The effects of process parameters such as stretch ratio, drawing sequence, drawing speed, and temperature were studied. Birefringence, mechanical properties, and thermal shrinkage of the stretched sheets were the focus of this study. A high orientation was achieved at high stretch ratio, and orientations from uniaxial to equi‐biaxial were obtained by controlling the relative magnitude of stretch ratio in machine (MD) and transverse (TD) directions. Stretching increased tensile strength and elongation at break significantly, which indicated an improvement in the toughness of the oriented PS sheets. Those properties were correlated with biaxial orientation factors: a rapid increase was observed for both tensile strength and elongation at break for birefringence levels above −0.005, and below, a plateau was observed. The shrinkage strain and stress were found to correlate well with the biaxial orientation factors. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 487–496, 2003
Ink‐eliminated waste paper sludge flour‐filled polypropylene composites with different coupling agent treatments
Authors: Qiao Xiuying , Zhang Yong , Zhang Yinxi , Zhu Yutang 
Published: April 2003

AbstractInk‐eliminated sludge flour (IESF), waste residue from the recycling treatments of waste paper, was utilized as a new kind of filler to reinforce polypropylene (PP) in this research work. Different coupling agents, including maleated anhydride grafted PP (MAPP), stearic acid (SA), and titanate (NDZ‐101), were used to increase the compatibility between IESF and PP. By using different measurements, the microstructure, morphology, thermal behaviors, and mechanical properties of the IESF/PP composites were investigated in detail. It was found that IESF, as a nucleation agent, not only induced the crystallization orientation of PP but also accelerate the crystallization rate of PP. Just as indicated in the experiments, the presence of IESF has shown the advantages of increasing the dimensional stability, the hardness and the flexural property, and the presence of coupling agents has a favorable effect on the improvement of dimensional stability. Moreover, the coupling agent has minor influence on the mechanical property, even causes some decrease in the impact strength. Among these three coupling agents, MAPP is found to be the best coupling agent for increasing the interfacial adhesion between IESF and PP, and the MAPP addition makes the PP composite possess the quickest crystallization rate and greatest tensile strength. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 513–520, 2003
Lack of Reelin causes malpositioning of nigral dopaminergic neurons: Evidence from comparison of normal and Relnrl mutant mice
Authors: Nishikawa Shigeyuki , Goto Satoshi , Yamada Kazumichi , Hamasaki Tadashi , Ushio Yukitaka 
Published: April 2003

AbstractThe reeler gene (Relnrl, formerly rl) product Reelin controls neuronal migration and positioning and thereby plays a key role in brain development. Mutation of Reln leads to widespread disruption of laminar cortical regions and ectopia in some brainstem nuclei. In the embryonic striatum of normal mice, a substantial expression of reelin mRNA has been documented; however, the anomalous positioning of neurons in the basal ganglia of reeler mice remains to be studied. We provide first evidence for a potential role of Reelin in the developmental formation of the substantia nigra. In reeler mutant mice lacking Reelin, dopaminergic neurons destined for the substantia nigra fail to migrate laterally and become anomalously clustered just lateral to the ventral tegmental area. Their axons appear to project to striatal patches forming “dopamine islands.” Results from the normal mice show that, at the midembryonic stage, Reelin identified with CR‐50 is highly concentrated in the ventral mesencephalon, where nigral dopaminergic neurons are in progress to migrate laterally to their eventual position of the adult brain. A combination of CR‐50 labeling and anterograde axonal tracing provided evidence that embryonic striatal neurons may supply the ventral portion of the mesencephalon with Reelin through their axonal projections. We hypothesize that Reelin plays a role in the positioning of nigral dopaminergic neurons and that it can act as an environmental cue at a remote site far from its birthplace via a transaxonal delivery system. J. Comp. Neurol. 461:166–173, 2003. © 2003 Wiley‐Liss, Inc.
Central projection of unmyelinated (C) primary afferent fibers from gastrocnemius muscle in the guinea pig
Authors: Ling Li‐Jun , Honda Takashi , Shimada Yasuhiro , Ozaki Noriyuki , Shiraishi Yousuke , Sugiura Yasuo 
Published: April 2003

AbstractWe have demonstrated the central projections of muscle C or group IV afferent fibers in the guinea pig by tracing arborizations in the spinal cord. C afferent fibers from the gastrocnemius muscle (GCM) were electrophysiologically identified by conduction velocity (less than 1 m/second). A single neuron in the lumbar 5 dorsal root ganglion (L5 DRG) was intracellularly labeled with Phaseolus vulgaris leucoagglutinin (PHA‐L). After iontophoretic injection of PHA‐L, we processed the lumbar cord and L5 DRG for PHA‐L immunohistochemistry. Six muscle C afferent fibers from 40 animals were labeled, and whole trajectories were recovered. Labeled fibers were reconstructed by tracing of the arbor in serial parasagittal sections. The GCM C afferents projected rostrocaudally for two or three segments and ran at the surface of the dorsal funiculus, giving off collaterals into laminae I and II and sometimes into parts of lamina III. We determined, based on the branching pattern and form of the terminal plexus, that the branching of muscle C afferent fibers showed an intermediate pattern that fell morphologically between the terminal patterns of somatic and visceral afferents. The numbers and sizes of fiber swellings and terminal swellings were measured on all collateral branches. We found that the area of distribution of the terminal swellings of muscle C afferent fibers is larger than that of somatic terminals but that the density of terminal swellings in the terminal area was lower than that of the somatic terminals. J. Comp. Neurol. 461:140–150, 2003. © 2003 Wiley‐Liss, Inc.
Novel, secondary sensory cell organ in ascidians: In search of the ancestor of the vertebrate lateral line
Authors: Burighel Paolo , Lane Nancy J. , Fabio Gasparini , Stefano Tiozzo , Zaniolo Giovanna , Carnevali Maria Daniela Candia , Manni Lucia 
Published: April 2003

AbstractA new mechanoreceptor organ, the “coronal organ,” located in the oral siphon, is described by light and electron microscopy in the colonial ascidiansBotryllus schlosseriandBotrylloides violaceus. It is composed of a line of sensory cells (hair cells), accompanied by supporting cells, that runs continuously along the margin of the velum and tentacles of the siphon. These hair cells resemble those of the vertebrate lateral line or, in general, the acoustico‐lateralis system, because they bear a single cilium, located centrally or eccentrically to a hair bundle of numerous stereovilli. In contrast to other sensory cells of ascidians, the coronal hair cells are secondary sensory cells, since they lack axonal processes directed towards the cerebral ganglion. Moreover, at their base they form synapses with nerve fibers, most of which exhibit acetylcholinesterase activity. The absence of axonal extensions was confirmed by experiments with lipophilic dyes. Different kinds of synapses were recognized: usually, each hair cell forms a few afferent synapses with dendrites of neurons located in the ganglion; efferent synapses, both axo‐somatic (between an axon coming from the ganglion and the hair cell) and axo‐dendritic (between an axon coming from the ganglion and an afferent fiber) were occasionally found. The presence of secondary sensory cells in ascidians is discussed in relation to the evolution of sensory cells and placodes in vertebrates. It is proposed that the coronal organ in urochordates is homologous to the vertebrate acoustico‐lateralis system. J. Comp. Neurol. 461:236–249, 2003. © 2003 Wiley‐Liss, Inc.
Patterning of the lateral ganglionic eminence by the Gsh1 and Gsh2 homeobox genes regulates striatal and olfactory bulb histogenesis and the growth of axons through the basal ganglia
Authors: Yun Kyuson , Garel Sonia , Fischman Seth , Rubenstein John L.R. 
Published: April 2003

AbstractThe function of the Gsh1 and Gsh2 homeobox transcription factors during development of the mouse telencephalon was studied using loss of function mutations. No telencephalic phenotype was observed in Gsh1 mutants, whereas Gsh2 and Gsh1/2 mutants showed progressively more severe defects in development of neurons derived from the lateral ganglionic eminence (LGE). These defects arise from abnormal dorsoventral specification of LGE progenitor cells. Mice lacking both Gsh1 and Gsh2 have severe hypoplasia of the striatum, olfactory tubercle, and interneurons that migrate from the dorsal LGE to the olfactory bulb. In addition, Gsh function is linked to the development of telencephalic dopaminergic neurons. These observations show that Gsh1 and Gsh2 have early roles in defining the identity of LGE progenitor cells. As a result of the basal ganglia defects in the Gsh1/2 mutants, there are pallial heterotopia near the cortical/subcortical limit and defects in the pathfinding of corticofugal and thalamocortical fibers. These findings highlight the developmental interdependence of adjacent telencephalic structures. J. Comp. Neurol. 461:151–165, 2003. © 2003 Wiley‐Liss, Inc.
Intraputamenal infusion of GDNF in aged rhesus monkeys: Distribution and dopaminergic effects
Authors: Ai Yi , Markesbery William , Zhang Zhiming , Grondin Richard , Elseberry Dennis , Gerhardt Greg A. , Gash Don M. 
Published: April 2003

AbstractSite‐specific delivery of trophic factors in the brain may be important for achieving therapeutic efficacy without unwanted side effects. This study evaluated the site‐specific infusion of glial cell line–derived neurotrophic factor (GDNF) into the right putamen of aged rhesus monkeys. After 4 weeks of continuous infusion at a rate of 22.5 μg/day, GDNF had diffused up to 11 mm from the catheter openings in the putamen into the rostral putamen, internal capsule, external capsule, caudate nucleus, and globus pallidus. Anisotropic flow along the external capsule tracts carried GDNF into the anterior amygdaloid area. Backflow of GDNF along the catheter track from the frontal cortex infiltrated juxtaposed corpus callosal and cortical tissue. GDNF was carried by retrograde transport to dopamine neurons in the ipsilateral substantia nigra, stimulating an 18% increase in the number of tyrosine hydroxylase (TH)–positive dopamine neurons and a 28% increase in dopamine neuron perikaryal size. Also, TH‐positive fiber density was increased in the ipsilateral globus pallidus, caudate nucleus, and putamen. Anatomic effects from GDNF stimulation of the dopaminergic system were restricted to the ipsilateral hemisphere. Retrograde GDNF labeling was also present in a few TH‐positive neurons in the locus coeruleus and a large cluster of TH‐negative neurons in the ventral anterior thalamus. Anterograde transport of GDNF was evident in axons in the pyramidal tract from the cerebral peduncle to the caudal spinal cord. Tissue injury from the intraparenchymal catheter and continuous infusion was confined primarily to a narrow zone surrounding the track and was mild to moderate in severity. J. Comp. Neurol. 461:250–261, 2003. © 2003 Wiley‐Liss, Inc.
Chronic nerve compression induces concurrent apoptosis and proliferation of Schwann cells
Authors: Gupta Ranjan , Steward Oswald 
Published: April 2003

AbstractChronic nerve compression (CNC), as in carpal tunnel syndrome, is a common cause of peripheral nerve dysfunction in humans. Previous studies using animal models have demonstrated progressive demyelination and a slowing of nerve conduction velocity. To characterize the Schwann cell response to CNC, we evaluated total Schwann cell number, apoptosis, and proliferation in an animal model of CNC. Design‐based stereologic techniques revealed a striking transient increase in Schwann cell number following CNC. Schwann cell number increased sixfold relative to the normal nerve at the site of compression at 1 month and then slowly declined toward control levels. Nevertheless, assays of apoptosis (TUNEL and an antipoly‐ADP‐ribose polymerase labeling assays) revealed extensive Schwann cell apoptosis at 2 weeks postcompression, which is during the time when Schwann cell number was increasing. Electron microscopic analysis confirmed that these dramatic changes in Schwann cells occurred in the absence of axon degeneration and axonal swelling and before there were any detectable alterations in nerve conduction velocity. Counts of bromodeoxyuridine‐labeled Schwann cells revealed that proliferation occurred concurrently with ongoing apoptosis. To define further the possible mitogenic properties of mechanical stimuli on Schwann cells, we used an in‐vitro model to deliver shear stress in the form of laminar fluid flow to pure populations of Schwann cells and confirmed that mechanical stimuli induce Schwann cell proliferation. Our findings indicate that chronic nerve compression induces Schwann cell turnover with minimal axonal injury and support the idea that mechanical stimuli have a direct mitogenic effect on Schwann cells. J. Comp. Neurol. 461:174–186, 2003. © 2003 Wiley‐Liss, Inc.
Increased expression of multiple neurofilament mRNAs during regeneration of vertebrate central nervous system axons
Authors: Gervasi Christine , Thyagarajan Amar , Szaro Ben G. 
Published: April 2003

AbstractCharacteristic changes in the expression of neuronal intermediate filaments (nIFs), an abundant cytoskeletal component of vertebrate axons, accompany successful axon regeneration. In mammalian regenerating PNS, expression of nIFs that are characteristic of mature neurons becomes suppressed throughout regeneration, whereas that of peripherin, which is abundant in developing axons, increases. Comparable changes are absent from mammalian injured CNS; but in goldfish and lamprey CNS, expression of several nIFs increases during axon regrowth. To obtain a broader view of the nIF response of successfully regenerating vertebrate CNS, in situ hybridization and video densitometry were used to track multiple nIF mRNAs during optic axon regeneration in Xenopus laevis. As in other successfully regenerating systems, peripherin expression increased rapidly after injury and expression of those nIFs characteristic of mature retinal ganglion cells decreased. Unlike the decrease in nIF mRNAs of regenerating PNS, that of Xenopus retinal ganglion cells was transient, with most nIF mRNAs increasing above normal during axon regrowth. At the peak of regeneration, increases in each nIF mRNA resulted in a doubling of the total amount of nIF mRNA, as well as a shift in the relative proportions contributed by each nIF. The relative proportions of peripherin and NF‐M increased above normal, whereas proportions of xefiltin and NF‐L decreased and that of XNIF remained the same. The increases in peripherin and NF‐M mRNAs were accompanied by increases in protein. These results are consistent with the hypothesis that successful axon regeneration involves changes in nIF subunit composition conducive to growth and argue that a successful injury response differs between CNS and PNS. J. Comp. Neurol. 461:262–275, 2003. © 2003 Wiley‐Liss, Inc.
Error analysis and Hertz vector approach for an electromagnetic interaction between a line current and a conducting plate
Authors: Attaf M.T. 
Published: April 2003

AbstractIn the present paper we first introduce the Hertz vector potential and examine how the specific case of electromagnetic field diffusion problems can be formulated in terms of this potential. Its connection to other commonly used potentials is presented and a basic approach in the form of a suitable set of equations is introduced. The suggested method is then successfully applied to solve the case of an electromagnetic interaction between a straight conductor carrying sinusoidal current and a finite thickness fixed plate. Due to the oscillatory aspect of the integral solution obtained, an appropriate numerical treatment is investigated and various curves are shown to illustrate the convergence behaviour. Copyright © 2003 John Wiley & Sons, Ltd.
Generalized non‐uniform transmission‐line models for local radiation from microstrip bends in MMICs
Authors: Liu Y. W. , Zhao D. S. , Mei K. K. 
Published: April 2003

AbstractAlthough microstrip bends in high‐speed digital MMICs have been widely investigated for the past two decades, their local radiation characteristics rather than their reflection characteristics have not been completely explored yet. In this paper, the generalized non‐uniform transmission‐line equations are used in analysing the microstrip bends including their local radiations. In our new models, the whole structure of a bend is regarded as a non‐uniform transmission line that is totally governed by the generalized non‐uniform transmission‐line equations. Except for analytical simplification and broad bandwidth performance, the new analysis could indicate where the strongly local radiations along a bend structure come from. Copyright © 2003 John Wiley & Sons, Ltd.
TLM simulation of microwave hybrid sintering of multiple samples in a multimode cavity
Authors: Amri A. , Saidane A. 
Published: April 2003

AbstractMicrowave heating technology is a powerful mean to ensure successful sintering of ceramic materials. In sintering experiments, low loss insulators, conductors and high‐loss ceramics are microwaved so as to get optimal mechanical and structural properties. It is known that low‐loss ceramic materials such alumina and zirconia exhibit long waiting time before reaching a critical coupling temperature at which microwaves can be readily absorbed. On the other hand, some ceramics such as silicon carbid have a high loss factor and therefore can be used as a process stimulus for microwave sintering of microwave transparent ceramics. Furthermore, successful sintering experiments often require the use of carefully designed insulating structure in order to minimize thermal gradients caused by heat loss from surfaces. All these problems have led to the introduction of microwave hybrid heating (MHH) schemes using higher dielectric loss susceptors, insulation or coating. Since MHH depend mainly on human expertise, the optimization of sintering experiments will certainly benefit from numerical simulations. The transmission line matrix (TLM) is used to study two MHH schemes where both a susceptor and an insulating matrix were, respectively, used as process stimulus for microwave heating of multiple alumina samples within a three‐dimensional multimode cavity. The effects of such MHH schemes and target settings on electric field distribution and power absorption rates are reported in this paper. Copyright © 2003 John Wiley & Sons, Ltd.