bluuebunny/crossref_metadata_2025_split huggingface dataset:
The glass transition, crystallization, and melting characteristics of a class of polyester ionomers
Authors: Guo Xian‐Ying , Gu Li‐Xia , Feng Xiao‐Xia 
Published: October 2002

AbstractThe glass transition temperature (Tg), crystallization, and melting character of a class of random polyester ionomers (polymer containing < 10 mol % ionic groups) were investigated. The nonlinear change of theTgand crystallization and melting behavior were characterized using differential scanning colorimetry (DSC). The ionomers are derived from polyethylene terephathalate (PET) modified through copolycondensation with a fully neutralized sulfonate moiety (sodiosulfo) isophthalate (Na‐SIP). Significant and systematic changes in the glass transition temperature and thermal characteristics upon addition of Na‐SIP on the PET backbone were observed, indicating strong association and interaction on the ionic species. At Na‐SIP levels ≥ 4 mol %, the turn of the the glass transition temperature was found, and the same results were obtained for the samples treated either by quenching or dissolution, suggesting the presence of reversible crosslink and aggregation of the ionic species within the organic matrix. When crystallized from the healing or cooling the samples during the DSC nonisothermal crystallization run at a 10°C/min, the enthalpy of the cold crystallization and melting showed an obvious decrease with the increase of Na‐SIP content, and changes of the crystal temperature had an analogy to those of theTg. A tune of the crystal temperature was found at Na‐SIP levels ≥ 3 mol % (see Figs.4,5, and7). The experimental data were discussed in the context of the restricted mobility model of the aggregation in the ionomers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3660–3666, 2002
Immiscible polymer blend electrorheological fluids: Composition dependence
Authors: Orihara Hiroshi , Kawasaki Tomohiko , Doi Masao , Inoue Akio 
Published: October 2002

AbstractWe investigated the composition dependence of the electrorheological properties of immiscible polymer blends which consist of liquid crystalline polymers (LCPs) and polydimethylsiloxane (DMS). We used two different kinds of LCPs, designated as A and B polymers. We observed that for a fixed ratio of an LCP and DMS (LCP:DMS = 2:1) the electrorheological properties change from type I to type II as the fraction of the A polymer is reduced. Microscopic observations indicate that the change in the electrorheological properties is associated with the structural change; in type I, LCP droplets are dispersed in DMS, while in type II, DMS droplets are dispersed and, furthermore, that the structural change is associated with the miscibility between DMS and the LCPs; the A polymer is partially miscible with DMS, while the B polymer is hardly miscible with DMS. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3673–3680, 2002
Copolymerization in UF/pMDI adhesives networks
Authors: Simon C. , George B. , Pizzi A. 
Published: October 2002

AbstractKinetic evidence in thermomechanical analysis experiments and carbon‐13 nuclear magnetic resonance spectroscopy (13C NMR) evidence indicates that the strength of a joint bonded with UF (urea–formaldehyde)/polymeric 4,4'‐diphenylmethane diisocyanate (pMDI) glue mixes is improved by coreaction of the methylol groups of UF resins with pMDI to form a certain number of methylene cross‐links. The formation of these methylene cross‐links is predominant, rather than formation of urethane bridges which still appear to form but which are in great minority. This reaction occurs in presence of water and under the predominantly acid hardening conditions, which is characteristic of aminoplastic resins (thus, in presence of a hardener). Coreaction occurs to a much lesser extent under alkaline conditions (hence, without UF resins hardeners). The predominant reaction is then different in UF/pMDI adhesive systems than that observed in phenol‐formaldehyde (PF)/pMDI adhesive systems. The same reaction observed for UF/pMDI system at higher temperatures has also been observed in PF/pMDI systems, but only at lower temperatures. The water introduced in the UF/pMDI mix by addition of the UF resin solution has been shown not to react with pMDI to an extent such as to contribute much, if at all, to the increase in strength of the hardened adhesive. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3681–3688, 2002
Maintenance of mechanical and viscoelastic properties in truck and off‐the‐road tire tread compounds by using 1,3 bis(citraconimidomethyl)benzene
Authors: Datta R. N. , Ingham F. A. A. 
Published: October 2002

AbstractThe effect of the antireversion agent 1,3 bis(citraconimidomethyl)benzene has been studied in a truck compound and a silica containing off‐the‐road compound. Laboratory results show that the antireversion agent significantly improves compound reversion resistance by means of a crosslink compensation mechanism. This improved reversion resistance provides a stabilization of viscoelastic properties on overcure and aging, which in turn should improve the performance of heavy duty tires with regard to rolling resistance and heat buildup throughout their service life. The antireversion agent is particularly effective in stabilizing viscoelastic properties in combination with a reduced level of the saline coupling agent, TESPT. This offers improved tire performance at no cost penalty. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3689–3694, 2002
Study of ionic polymer toughening epoxy resin
Authors: Chen Su‐Chen , Chiu Hsien‐Tang , Ye Chug‐Pin 
Published: October 2002

AbstractIn this study, PEL [copolymer of poly(propylene) oxide (PPO) and poly(ethylene oxide) (PEO)] toughening epoxy resin with ionic charge was used to produce an interpenetrating action between the cross‐linking network structure of the epoxy resin and the PEL additive. Fourier transform infrared (FTIR) analysis of the toughening epoxy resin revealed that NCO disappeared at 2400 cm−1, NH appeared at 3300 cm−1, and CO appeared at 1750 cm−1. These results indicate that a urethane bond was produced. Dynamic mechanical analysis (DMA) and mechanical testing results indicated that as the level of PEL increased, the compatibility between the epoxy resin and PEL also increased. In addition, the compatibility was improved because the addition of cornate hardener produced a graft phenomenon. The tensile property, impact strength, and fracture toughness of PEL toughening epoxy resin all had a tendency to improve. The tensile strength, impact strength, and fracture toughness (KIC value) were most improved when 30 phr cornate was added. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3740–3751, 2002
Identification of a “glycine‐loop”‐like coiled structure in the 34 AA Pro,Gly,Met repeat domain of the biomineral‐associated protein, PM27
Authors: Wustman Brandon A. , Santos Rudolpho , Zhang Bo , Evans John Spencer 
Published: October 2002

AbstractFracture resistance in biomineralized structures has been linked to the presence of proteins, some of which possess sequences that are associated with elastic behavior. One such protein superfamily, the Pro,Gly‐rich sea urchin intracrystalline spicule matrix proteins, form protein–protein supramolecular assemblies that modify the microstructure and fracture‐resistant properties of the calcium carbonate mineral phase within embryonic sea urchin spicules and adult sea urchin spines. In this report, we detail the identification of a repetitive keratin‐like “glycine‐loop”‐ or coil‐like structure within the 34‐AA (AA: amino acid) N‐terminal domain, (PGMG)8PG, of the spicule matrix protein, PM27. The identification of this repetitive structural motif was accomplished using two capped model peptides: a 9‐AA sequence, GPGMGPGMG, and a 34‐AA peptide representing the entire motif. Using CD, NMR spectrometry, and molecular dynamics simulated annealing/minimization simulations, we have determined that the 9‐AA model peptide adopts a loop‐like structure at pH 7.4. The structure of the 34‐AA polypeptide resembles a coil structure consisting of repeating loop motifs that do not exhibit long‐range ordering. Given that loop structures have been associated with protein elastic behavior and protein motion, it is plausible that the 34‐AA Pro,Gly,Met repeat sequence motif in PM27 represents a putative elastic or mobile domain. © 2002 Wiley Periodicals, Inc. Biopolymers 65: 362–372, 2002
Ultrastructure of retinal ganglion cell death after axotomy in chick embryos
Authors: Borsello Tiziana , Mottier Vincent , Castagné Vincent , Clarke Peter G.H. 
Published: October 2002

AbstractAxotomy often leads to neuronal death, which occurs after a particularly short delay in immature animals. Tectal lesions were made in embryonic day (E) 12 chick embryos, thereby axotomizing the retinal ganglion cells of the contralateral eye, which then died within 3 days. We here describe the ultrastructural changes in the axotomized ganglion cells. The main changes were nuclear invagination and type 3B (cytoplasmic type) cell death characterized by dilation of the perinuclear space, endoplasmic reticulum, and Golgi apparatus. However, nuclear invagination was never seen in type 3B dying cells. All the axotomy‐induced retinal ganglion cell death appears to have been of type 3B; apoptosis was not induced by axotomy, as was confirmed by additional light microscopic experiments showing that it did not increase the frequency of apoptotic markers revealed by terminal deoxynucleotidyl transferase‐mediated biotinylated UTP nick end labeling (the TUNEL method) labeling and immunoreactivity for activated caspase‐3. However, the latter methods did show small numbers of apoptotic cells dying naturally even in control retinas. After the death of the axotomized ganglion cells, they were phagocytosed mainly in Müller processes. The present findings open up the chick tectal lesion model as a system for analyzing type 3B neuronal death in vivo. J. Comp. Neurol. 453:361–371, 2002. © 2002 Wiley‐Liss, Inc.
Pituitary adenylate cyclase‐activating peptide in the rat central nervous system: An immunohistochemical and in situ hybridization study
Authors: Hannibal Jens 
Published: October 2002

AbstractIn the present study the localization of pituitary adenylate cyclase‐activating peptide (PACAP)‐expressing cell bodies and PACAP projections were mapped in the adult rat brain and spinal cord by using immunohistochemistry and in situ hybridization histochemistry. A widespread occurrence of PACAP‐containing cell bodies was found, with the greatest accumulation in several hypothalamic nuclei and in several brainstem nuclei, especially the habenular nuclei, the pontine nucleus, the lateral parabrachial nucleus (LPB), and the vagal complex. PACAP was also present in cell bodies in the olfactory areas, in neocortical areas, in the hippocampus, in the vestibulo‐ and cochlear nuclei, in cell bodies of the intermediolateral cell column of the spinal cord and in Purkinje cells of the cerebellum, in the subfornical organ, and in the organum vasculosum of the lamina terminalis. An intense accumulation of PACAP‐immunoreactive (‐IR) nerve fibers was observed throughout the hypothalamus, in the amydaloid and extended amygdaloid complex, in the anterior and paraventricular thalamic nuclei, in the intergeniculate leaflet, in the pretectum, and in several brainstem nuclei, such as the parabrachial nucleus, the sensory trigeminal nucleus, and the nucleus of the solitary tract. PACAP‐IR nerve fibers were also found in the area postrema, the posterior pituitary and the choroid plexus, and the dorsal and ventral horn of the spinal cord. The widespread distribution of PACAP in the brain and spinal cord suggests that PACAP is involved in the control of many autonomic and sensory functions as well as higher cortical processes. J. Comp. Neurol. 453:389–417, 2002. © 2002 Wiley‐Liss, Inc.
Developmental patterns of cadherin expression and localization in relation to compartmentalized thalamocortical terminations in rat barrel cortex
Authors: Gil Orlando D. , Needleman Leigh , Huntley George W. 
Published: October 2002

AbstractThe wiring of synaptic circuitry during development is remarkably precise, but the molecular interactions that enable such precision remain largely to be defined. Cadherins are cell adhesion molecules hypothesized to play roles in axon growth and synaptic targeting during development. We previously showed that N‐cadherin localizes to ventrobasal (VB) thalamocortical synapses in rat somatosensory (barrel) cortex during formation of the whisker‐map in layer IV (Huntley and Benson [1999] J. Comp. Neurol. 407:453–471). Such specific association of N‐cadherin with one identified afferent pathway raises the prediction that other cadherins are expressed in barrel cortex and that these are, in some combination, also differentially associated with distinct inputs. Here, we first show that N‐cadherin and three other classic cadherins (cadherin‐6, ‐8, and ‐10) are expressed contemporaneously in barrel cortex with relative levels of postnatal expression that are highest during the first 2 weeks, when afferent and intrinsic circuitries are forming and synaptogenesis is maximal. Each displayed distinct, but partly overlapping laminar patterns of expression that changed over time. Cadherin‐8 probe hybridization formed a particularly striking pattern of intermittent, columnar patches extending from layer V through layer III, which was first detectable at approximately postnatal day 3. The patches were centered precisely over regions of dysgranular layer IV and, in the whisker barrel field, over barrel septa. This pattern is similar to that formed by the terminal distribution of thalamocortical afferents arising from the posterior nucleus (POm), suggesting cadherin‐8 association with the POm thalamocortical synaptic circuit. Consistent with this, cadherin‐8 mRNAs were enriched in the POm nucleus, and cadherin‐8 immunolabeling in layer IV was enriched in barrel septa and codistributed with labeled POm thalamocortical synaptic‐like puncta. The striking molecular parcellation of at least two different cadherins to the two, converging thalamic pathways that terminated in non‐overlapping barrel center and septal compartments in layer IV strongly suggested that cadherins provide requisite molecular recognition and targeting that enable precise construction of thalamocortical and other synaptic circuitry. J. Comp. Neurol. 453:372–388, 2002. © 2002 Wiley‐Liss, Inc.
Factors influencing periglacial fluvial morphology in the northern European Russian tundra and taiga
Authors: Huisink M. , de Moor J. J. W. , Kasse C. , Virtanen T. 
Published: October 2002

AbstractThe influence of geology, discharge regime, slope, vegetation type, vegetation density and permafrost conditions on periglacial channel morphology has been investigated in the Usa catchment (northern European Russia). Rivers are dominated by meandering or anabranching plan forms and rarely show braiding characteristics, despite a nival discharge regime, the presence of discontinuous permafrost and locally steep slopes.The dense vegetation cover is an important factor in determining the meandering morphology as it inhibits the sediment supply and hence braided conditions. Differences in vegetation types (taiga in the south, tundra in the north) have no effect on channel plan form. Copyright © 2002 John Wiley & Sons, Ltd.
Road construction and gully erosion in West Pokot, Kenya
Authors: Jungerius P. D. , Matundura J. , van de Ancker J. A. M. 
Published: October 2002

AbstractThe study of soil erosion in Kenya is largely limited to agricultural and pastoral land. Little attention has been given to the effects of roads on soil erosion, although they cause more inconvenience than any other form of soil erosion. The object of this study is the B4, an unpaved road leading from the Marich Pass up the Kerio valley. This road runs across the footslopes of a steep scarp fault, in a climate with torrential rainfall. The footslopes consist of alluvial fans, pediments and terraces. Aerial photographs from 1963 show no erosion along the road: the 162 culverts and drifts were apparently adequate to cope with the drainage of the footslopes. Roadside gully formation is now a big problem for the road engineers.The 1 km sections of the road marked by the Ministry of Public Works have been used as the units of research, to facilitate exchange of information with the road engineers. In each section of the first 42 km of the road, the volumes of the roadside gullies were measured, along with erosion factors related to type of cross‐drainage construction, stability of the roadside material, geomorphological parameters and decrease in soil cover above the road since 1963. There is a strong correlation between roadside gullies, alluvial fans and decrease of soil cover.The road engineers were guided by geomorphological principles when designing the road. They preferred drifts, although these dips in the road surface are uncomfortable to pass by car. Drifts resemble natural drainage channels more closely than culverts and cause less damage in the fields below the road. The later settlers also showed geomorphological sense by preferring the smooth surfaces and well drained fine‐grained soils of the alluvial fans.The research demonstrates a common problem of road design in developing countries: however carefully the measures against erosion are designed, they become rapidly outdated because a new road attracts settlement. Deterioration of surface drainage and erosion start at unforeseeable points where people choose to settle. Copyright © 2002 John Wiley & Sons, Ltd.
Microglia as liaisons between the immune and central nervous systems: Functional implications for multiple sclerosis
Authors: Carson Monica J. 
Published: October 2002

AbstractMultiple sclerosis is a chronic demyelinating inflammatory disease of the central nervous system (CNS). As the tissue macrophage of the CNS, microglia have the potential to regulate and be regulated by cells of the CNS and by CNS‐infiltrating immune cells. The exquisite sensitivity of microglia to these signals, coupled with their ability to develop a broad range of effector functions, allows the CNS to tailor microglial function for specific physiological needs. However, the great plasticity of microglial responses can also predispose these cells to amplify disproportionately the irrelevant or dysfunctional signals provided by either the CNS or immune systems. The consequences of such an event could be the conversion of self‐limiting inflammatory responses into chronic neurodegeneration and may explain in part the heterogeneous nature of multiple sclerosis. GLIA 40:218–231, 2002. © 2002 Wiley‐Liss, Inc.
Microglia in human immunodeficiency virus‐associated neurodegeneration
Authors: Garden Gwenn A. 
Published: October 2002

AbstractInfection with the human immunodeficiency virus (HIV) is associated with a syndrome of cognitive and motor abnormalities that may develop in the absence of opportunistic infections. Neurons are not productively infected by HIV. Thus, one hypothesis to explain the pathophysiology of HIV‐associated dementia (HAD) suggests that signals released from other infected cell types in the CNS secondarily lead to neuronal injury. Microglia are the predominant resident CNS cell type productively infected by HIV‐1. Neurologic dysfunction in HAD appears to be a consequence of microglial infection and activation. Several neurotoxic immunomodulatory factors are released from infected and activated microglia, leading to altered neuronal function, synaptic and dendritic degeneration, and eventual neuronal apoptosis. This review summarizes findings from clinical/pathological studies, animal models, and in vitro models of HAD. Most of these studies support the hypothesis that altered microglial physiology is the nidus for a cascade of events leading to neuronal dysfunction and death. Several molecular mediators of neuronal injury in HAD that emanate from microglia have been identified, and strategies for altering the impact of these neurotoxins are discussed. GLIA 40:240–251, 2002. © 2002 Wiley‐Liss, Inc.
The forward rate unbiasedness hypothesis revisited
Authors: Razzak W.A. 
Published: October 2002

AbstractIt is widely accepted that long‐term interest rates are more suitable for testing the Uncovered Interest Rate Parity (UIP) than shorter‐term rates. This paper shows that while using longer‐term (1‐year) forward exchange rates are also more suitable than shorter‐term rates (1‐month) for testing the forward exchange rate unbiasedness hypothesis (FRUH) the test is sensitive to the choice of the numeraire currency, i.e. the US dollar, the Deutsche mark (DM) or the Japanese yen. The FRUH holds in currencies measured in terms of the US dollar when a one‐year forward contract is used instead of a one‐month contract, but it does not hold when the DM and the yen are used as numeraire currencies. Copyright © 2002 John Wiley & Sons, Ltd.
A general equilibrium analysis of foreign direct investment and the real exchange rate
Authors: Shrikhande Milind M. 
Published: October 2002

AbstractModern theories of foreign direct investment claim that foreign direct investment occurs because certain domestic assets are worth more under foreign control. This view developed by industrial organization theorists is indifferent to the financing mode of a foreign acquisition as well as to the interaction between foreign direct investment (FDI) and real exchange rates. However, empirical research has uncovered a significant relationship between FDI and exchange rates. Second, partial equilibrium models of FDI have focused on FDI as foreign acquisitions of existing assets but not on new capital formation initiated by foreigners. We complement these contributions by developing a welfare‐maximizing, general equilibrium model of the interaction between FDI as cross‐border acquisitions, and the real exchange rate. Copyright © 2002 John Wiley & Sons, Ltd.
Discrete policy interventions and rational forecast errors in foreign exchange markets: the uncovered interest parity hypothesis revisited
Authors: Kirikos Dimitris G. 
Published: October 2002

AbstractThis paper combines policy response explanations of the uncovered interest parity puzzle with a time series approach that accounts for discrete central bank interventions. When monetary authorities manage the interest rate differential through an anti‐inflationary policy rule, which allows for discrete shifts, then a stochastic segmented trends representation seems appropriate for the exchange rate and the interest rate differential series. In this setting, rational forecast errors are possible, and a test of the uncovered parity hypothesis, based on the cross‐equation restrictions on a Markov switching process, suggests that the parity relationship cannot be rejected for three European currencies vis‐à‐vis the US dollar. Copyright © 2002 John Wiley & Sons, Ltd.