bluuebunny/crossref_metadata_2025 huggingface dataset:
Our Master's Voice: F. Max Müller after A Hundred Years of Solitude
Authors: Masuzawa Tomoko
Published: January 2004

Although recognized as a nineteenth-century champion of comparative methods and leading figure in the founding of the science of religion, F. Max Müller has been paid surprisingly little attention since his death a century ago. In 2002, a substantial scholarly biography by Lourens P. van den Bosch and an anthology of Müller's representative works edited by Jon Stone were published. Through a review of these two publications, this article first retraces the familiar contour of the "life and work" of Müller as a progenitor of Religionswissenschaft, an image that both these texts help resuscitate. In the second part of the article it is suggested that, when the voluminous extant material is viewed from another angle, a considerably different portrait of Müller comes to the foreground, especially if his life-long engagement in comparative philology is taken more seriously, rather than treated as a merely preliminary or technical aspect of his scholarly profile. In this alternative perspective, it appears that Müller was generally indifferent to theology, and that he saw religious concerns and worries more as a propensity of other people around him that continually came to disturb his scholarship from without, rather than as something that motivated his own work from within.
Sacred Capital: Pierre Bourdieu and the Study of Religion
Authors: Urban Hugh
Published: January 2004

This article offers a critical analysis of Pierre Bourdieu's work and its importance for the study of religion. Analysis and criticim of Bourdieu's theories with reference to the example of the Bāuls, a loose, eclectic tradition of wandering minstrels and self-proclaimed spiritual "madmen", which has flourished throughout Bengal (northeast India and Bangladesh) since at least the late nineteenth century, was chosen for two reasons: first, because much like Bourdieu, the Bāuls make frequent use of a "marketplace" metaphor to describe the larger realms of social interaction and religious discourse; second, because the Bāuls offer a powerful challenge to Bourdieu's work, demonstrating that there is perhaps far more room for subversion and critique of the dominant "social marketplace" than his model of society and culture seems to allow.
Changes in the Effect of Spinal Prostaglandin E2during Inflammation: Prostaglandin E (EP1-EP4) Receptors in Spinal Nociceptive Processing of Input from the Normal or Inflamed Knee Joint
Authors: Bär Karl-Jürgen , Natura Gabriel , Telleria-Diaz Alejandro , Teschner Philipp , Vogel Regine , Vasquez Enrique , Schaible Hans-Georg , Ebersberger Andrea
Published: January 2004

Inflammatory pain is caused by sensitization of peripheral and central nociceptive neurons. Prostaglandins substantially contribute to neuronal sensitization at both sites. Prostaglandin E2(PGE2) applied to the spinal cord causes neuronal hyperexcitability similar to peripheral inflammation. Because PGE2can act through EP1-EP4 receptors, we addressed the role of these receptors in the spinal cord on the development of spinal hyperexcitability. Recordings were made from nociceptive dorsal horn neurons with main input from the knee joint, and responses of the neurons to noxious and innocuous stimulation of the knee, ankle, and paw were studied after spinal application of recently developed specific EP1-EP4 receptor agonists. Under normal conditions, spinal application of agonists at EP1, EP2, and EP4 receptors induced spinal hyperexcitability similar to PGE2. Interestingly, the effect of spinal EP receptor activation changed during joint inflammation. When the knee joint had been inflamed 7-11 hr before the recordings, only activation of the EP1 receptor caused additional facilitation, whereas spinal application of EP2 and EP4 receptor agonists had no effect. Additionally, an EP3α receptor agonist reduced responses to mechanical stimulation. The latter also attenuated spinal hyperexcitability induced by spinal PGE2. In isolated DRG neurons, the EP3α agonist reduced the facilitatory effect of PGE2on TTX-resistant sodium currents. Thus pronociceptive effects of spinal PGE2can be limited, particularly under inflammatory conditions, through activation of an inhibitory splice variant of the EP3 receptor. The latter might be an interesting target for controlling spinal hyperexcitability in inflammatory pain states.
Intracellular Astrocyte Calcium WavesIn SituIncrease the Frequency of Spontaneous AMPA Receptor Currents in CA1 Pyramidal Neurons
Authors: Fiacco Todd A. , McCarthy Ken D.
Published: January 2004

Spontaneous neurotransmitter release and activation of group I metabotropic glutamate receptors (mGluRs) each play a role in the plasticity of neuronal synapses. Astrocytes may contribute to short- and long-term synaptic changes by signaling to neurons via these processes. Spontaneous whole-cell AMPA receptor (AMPAR) currents were recorded in CA1 pyramidal cellsin situwhile evoking Ca2+increases in the adjacent stratum radiatum astrocytes by uncaging IP3. Whole-cell patch clamp was used to deliver caged IP3and the Ca2+indicator dye Oregon green BAPTA-1 to astrocytes. Neurons were patch-clamped and filled with Alexa 568 hydrazide dye to visualize their morphological relationship to the astrocyte. On uncaging of IP3, astrocyte Ca2+responses reliably propagated as a wave into the very fine distal processes, synchronizing Ca2+activity within astrocyte microdomains. The intracellular astrocyte Ca2+wave coincided with a significant increase in the frequency of AMPA spontaneous EPSCs, but with no change in their kinetics. AMPAR current amplitudes were increased as well, but not significantly (p= 0.06). The increased frequency of AMPAR currents was sensitive to the group I mGluR antagonistsLY367385and 2-methyl-6-(phenylethynyl)-pyridine, suggesting that (1) astrocytes released glutamate in response to IP3uncaging, and (2) glutamate released by astrocytes activated group I mGluRs to facilitate the release of glutamate from excitatory neuronal presynaptic boutons. These results extend previous studies, which have shown astrocyte modulation of neuronal activityin vitroand suggest that astrocyte-to-neuron signaling in intact tissue may contribute to synaptic plasticity.
M Channels Containing KCNQ2 Subunits Modulate Norepinephrine, Aspartate, and GABA Release from Hippocampal Nerve Terminals
Authors: Martire Maria , Castaldo Pasqualina , D'Amico Monia , Preziosi Paolo , Annunziato Lucio , Taglialatela Maurizio
Published: January 2004

KCNQ subunits encode for the M current (IKM), a neuron-specific voltage-dependent K+current with a well established role in the control of neuronal excitability. In this study, by means of a combined biochemical, pharmacological, and electrophysiological approach, the role of presynapticIKMin the release of previously taken up tritiated norepineprine (NE), GABA, andd-aspartate (d-ASP) from hippocampal nerve terminals (synaptosomes) has been evaluated. Retigabine (RT) (0.01-30 μm), a specific activator ofIKM, inhibited [3H]NE, [3H]d-ASP, and [3H]GABA release evoked by 9 mmextracellular K+([K+]e). RT-induced inhibition of [3H]NE release was prevented by synaptosomal entrapment of polyclonal antibodies directed against KCNQ2 subunits, an effect that was abolished by antibody preabsorption with the KCNQ2 immunizing peptide; antibodies against KCNQ3 subunits were ineffective. Flupirtine (FP), a structural analog of RT, also inhibited 9 mm[K+]e-induced [3H]NE release, although its maximal inhibition was lower than that of RT. Electrophysiological studies in KCNQ2-transfected Chinese hamster ovary cells revealed that RT and FP (10 μm) caused a -19 and -9 mV hyperpolarizing shift, respectively, in the voltage dependence of activation of KCNQ2 K+channels. In the same cells, the cognition enhancer 10,10-bis(4-pyridinylmethyl)-9(10H)-anthracenone (XE-991) (10 μm) blocked KCNQ2 channels and prevented their activation by RT (1-10 μm). Finally, both XE-991 (10-100 μm) and tetraethylammonium ions (100 μm) abolished the inhibitory effect of RT (1 μm) on [3H]NE release. These findings provide novel evidence for a major regulatory role of KCNQ2 K+channel subunits in neurotransmitter release from rat hippocampal nerve endings.
Distance-Dependent Scaling of Calcium Transients Evoked by Backpropagating Spikes and Synaptic Activity in Dendrites of Hippocampal Interneurons
Authors: Rozsa Balazs , Zelles Tibor , Vizi E. Sylvester , Lendvai Balazs
Published: January 2004

Although interactions between backpropagating action potentials and synaptic stimulations have been extensively studied in pyramidal neurons, dendritic propagation and the summation of these signals in interneurons are not nearly as well known. In this study, two-photon imaging was used to explore the basic properties of dendritic calcium signaling in CA1 stratum radiatum interneurons. In contrast to hippocampal pyramidal neurons, the backpropagating action potential-evoked calcium transients in dendrites of interneurons underwent a distance-dependent increment. Although, in proximal dendrites, an increment could be attributed to a smaller dendrite diameter, distal dendrites did not show such dependence. Calcium responses in interneurons had a smaller amplitude, slower rise time, and decay than in pyramidal neurons. To explore the factors underlying the difference, we compared the calcium-binding capacity in interneurons and in pyramidal neurons. Our finding that endogenous calcium buffers had a higher level in interneurons may primarily explain the different kinetics and amplitudes of calcium transients. Synaptic stimulation-evoked calcium transients were also larger at distant dendritic locations. The spread of these signals was restricted to 12-13 μm long dendritic compartments. Supporting the reported lack of long-term potentiation in these interneurons, we found only sublinear or linear summations of calcium responses to coincident synaptic inputs and backpropagating spikes.
The Suprachiasmatic Nucleus Entrains, But Does Not Sustain, Circadian Rhythmicity in the Olfactory Bulb
Authors: Granados-Fuentes Daniel , Prolo Laura M. , Abraham Ute , Herzog Erik D.
Published: January 2004

The suprachiasmatic nucleus (SCN) of the hypothalamus has been termed the master circadian pacemaker of mammals. Recent discoveries of damped circadian oscillators in other tissues have led to the hypothesis that the SCN synchronizes and sustains daily rhythms in these tissues. We studied the effects of constant lighting (LL) and of SCN lesions on behavioral rhythmicity andPeriod 1(Per1) gene activity in the SCN and olfactory bulb (OB). We found that LL had similar effects on cyclic locomotor and feeding behaviors andPer1expression in the SCN but had no effect on rhythmicPeriod 1expression in the OB. LL lengthened the period of locomotor and SCN rhythms by ∼1.6 hr. After 2 weeks in LL, nearly 35% of rats lost behavioral rhythmicity. Of these, 90% showed no rhythm inPer1-driven expression in their SCN. Returning the animals to constant darkness rapidly restored their daily cycles of running wheel activity and gene expression in the SCN. In contrast, the OB remained rhythmic with no significant change in period, even when cultured from animals that had been behaviorally arrhythmic for 1 month. Similarly, we found that lesions of the SCN abolished circadian rhythms in behavior but not in the OB. Together, these results suggest that LL causes the SCN to lose circadian rhythmicity and its ability to coordinate daily locomotor and feeding rhythms. The SCN, however, is not required to sustain all rhythms because the OB continues to oscillatein vivowhen the SCN is arrhythmic or ablated.
The Transition from Development to Motor Control Function in the Corticospinal System
Authors: Meng Zhuo , Li Qun , Martin John H.
Published: January 2004

During early postnatal development, corticospinal (CS) system stimulation, electrical or transcranial magnetic, is minimally effective in producing muscle contraction, despite having axon terminals that excite spinal neurons. Later, after stimulation becomes more effective, the cortical motor representation develops, and movements the system controls in maturity are expressed. We determined whether development of temporal facilitation (response enhancement produced by the second of a pair of pyramidal tract stimuli, or a higher stimulus multiple of a train of stimuli) correlated with these changes. Facilitation of the monosynaptic CS response was larger in older kittens and adults than younger kittens. When facilitation was strong, strong motor responses were evoked by pyramidal stimulation with small currents and few pulses. With strong facilitation in older kittens, corticospinal axon varicosities colocalize synaptophysin like adults, suggesting a presynaptic mechanism. With effective facilitation, control signals from the cortex can be sufficiently effective to provoke muscle contraction for guiding movements.
Columnar Specificity of Microvascular Oxygenation and Volume Responses: Implications for Functional Brain Mapping
Authors: Sheth Sameer A. , Nemoto Masahito , Guiou Michael , Walker Melissa , Pouratian Nader , Hageman Nathan , Toga Arthur W.
Published: January 2004

Cortical neurons with similar properties are grouped in columnar structures and supplied by matching vascular networks. The hemodynamic response to neuronal activation, however, is not well described on a fine spatial scale. We investigated the spatiotemporal characteristics of microvascular responses to neuronal activation in rat barrel cortex using optical intrinsic signal imaging and spectroscopy. Imaging was performed at 570 nm to provide functional maps of cerebral blood volume (CBV) changes and at 610 nm to estimate oxygenation changes. To emphasize parenchymal rather than large vessel contributions to the functional hemodynamic responses, we developed an ANOVA-based statistical analysis technique. Perfusion-based maps were compared with underlying neuroanatomy with cytochrome oxidase staining. Statistically determined CBV responses localized accurately to individually stimulated barrel columns and could resolve neighboring columns with a resolution better than 400 μm. Both CBV and early oxygenation responses extended beyond anatomical boundaries of single columns, but this vascular point spread did not preclude spatial specificity. These results indicate that microvascular flow control structures providing targeted flow increases to metabolically active neuronal columns also produce finely localized changes in CBV. This spatial specificity, along with the high contrast/noise ratio, makes the CBV response an attractive mapping signal. We also found that functional oxygenation changes can achieve submillimeter specificity not only during the transient deoxygenation (“initial dip”) but also during the early part of the hyperoxygenation. We, therefore, suggest that to optimize hemodynamic spatial specificity, appropriate response timing (using ≤2-3 sec changes) is more important than etiology (oxygenation or volume).
Menthol-Induced Ca2+Release from Presynaptic Ca2+Stores Potentiates Sensory Synaptic Transmission
Authors: Tsuzuki Kenzo , Xing Hong , Ling Jennifer , Gu Jianguo G.
Published: January 2004

Menthol and many of its derivatives produce profound sensory and mental effects. The receptor for menthol has been cloned and named cold- and menthol-sensitive receptor-1 (CMR1) or transient receptor potential channel M8 (TRPM8) receptor. Using a dorsal root ganglion (DRG) and dorsal horn (DH) coculture system as a model for the first sensory synapse in the CNS, we studied menthol effects on sensory synaptic transmission and the underlying mechanisms. We found that menthol increased the frequency of miniature EPSCs (mEPSCs). The effects persisted under an extracellular Ca2+-free condition but were abolished by intracellular BAPTA and pretreatment with thapsigargin. Menthol-induced increases of mEPSC frequency were blocked by 2-aminoethoxydiphenylborane (2-APB) but not affected by the phospholipase C inhibitor U73122 or by the cADP receptor inhibitor 8-bromo-cADPR (8Br-cADPR). Double-patch recordings from DRG-DH pairs showed that menthol could potentiate evoked EPSCs (eEPSCs) and change the paired-pulse ratio of eEPSCs. A Ca2+imaging study on DRG neurons demonstrated that menthol could directly release Ca2+from intracellular Ca2+stores. Menthol-induced Ca2+release was abolished by 2-APB but not affected by U73122 or 8Br-cADPR. Taken together, our results indicate that menthol can act directly on presynaptic Ca2+stores of sensory neurons to release Ca2+, resulting in a facilitation of glutamate release and a modulation of neuronal transmission at sensory synapses. Expression of TRPM8 receptor on presynaptic Ca2+stores, a novel localization for this ligand-gated ion channel, is also strongly suggested.
Overexpression of Adenosine Kinase in Epileptic Hippocampus Contributes to Epileptogenesis
Authors: Gouder Nicolette , Scheurer Louis , Fritschy Jean-Marc , Boison Detlev
Published: January 2004

Endogenous adenosine in the brain is thought to prevent the development and spread of seizures via a tonic anticonvulsant effect. Brain levels of adenosine are primarily regulated by the activity of adenosine kinase. To establish a link between adenosine kinase expression and seizure activity, we analyzed the expression of adenosine kinase in the brain of control mice and in a kainic acid-induced mouse model of mesial temporal lobe epilepsy. Immunohistochemical analysis of brain sections of control mice revealed intense staining for adenosine kinase, mainly in astrocytes, which were more or less evenly distributed throughout the brain, as well as in some neurons, particularly in olfactory bulb, striatum, and brainstem. In contrast, hippocampi lesioned by a unilateral kainic acid injection displayed profound astrogliosis and therefore a significant increase in adenosine kinase immunoreactivity accompanied by a corresponding increase of enzyme activity, which paralleled chronic recurrent seizure activity in this brain region. Accordingly, seizures and interictal spikes were suppressed by the injection of a low dose of the adenosine kinase inhibitor 5-iodotubercidin. We conclude that overexpression of adenosine kinase in discrete parts of the epileptic hippocampus may contribute to the development and progression of seizure activity.
Neural Bases of Set-Shifting Deficits in Parkinson's Disease
Authors: Monchi Oury , Petrides Michael , Doyon Julien , Postuma Ronald B. , Worsley Keith , Dagher Alain
Published: January 2004

Patients with Parkinson's disease (PD) exhibit impairments in several cognitive functions similar to those observed in patients with prefrontal cortex (PFC) lesions. The physiological origins of these cognitive deficits are not well documented. Two mechanisms have been proposed: disruptions in corticostriatal circuits or a deficiency in frontal dopamine. We previously used functional magnetic resonance imaging (fMRI) in young healthy subjects to separate patterns of PFC and striatum activity during distinct phases of performance of the Wisconsin Card Sorting Task, a set-shifting task that reveals deficits in patients with PD. Here, the same fMRI protocol was used in PD patients and matched controls. Decreased activation was observed in the PD group compared with the matched control group in the ventrolateral PFC when receiving negative feedback and the posterior PFC when matching after negative feedback. In controls, these prefrontal regions specifically coactivated with the striatum during those stages of task performance. In contrast, greater activation was found in the PD group compared with the matched control group in prefrontal regions, such as the posterior and the dorsolateral PFC when receiving positive or negative feedback, that were not coactivated with the striatum in controls. These results suggest that both nigrostriatal dopamine depletion and intracortical dopamine deficiency may play a role in cognitive deficits in PD, depending on the involvement of the striatum in the task at hand.
A C-Terminal Determinant of GluR6 Kainate Receptor Trafficking
Authors: Yan Sheng , Sanders James M. , Xu Jian , Zhu Yongling , Contractor Anis , Swanson Geoffrey T.
Published: January 2004

Intracellular trafficking of ionotropic glutamate receptors is regulated predominantly by determinants in the cytoplasmic C-terminal domain of the subunit proteins. Although AMPA receptors are found at the vast majority of excitatory synapses, synaptic kainate receptors exhibit a much more restricted distribution, suggesting that specific mechanisms exist for selective trafficking of these receptor proteins. In this report, we define a critical forward trafficking motif that is necessary for surface expression of the glutamate receptor 6 (GluR6) kainate receptor as well as chimeric proteins containing only the GluR6 C-terminal domain. The trafficking determinant was identified by tracking surface expression of green fluorescent protein-tagged GluR6 receptors with confocal immunofluorescence in COS-7 cells and cultured neurons and patch-clamp electrophysiology in human embryonic kidney 293 cells. Serial truncation and alanine site mutagenesis of the GluR6 subunit C terminus localized the critical motif to a seven amino acid stretch of predominantly basic residues. Alanine mutation of the trafficking motif reduced kainate receptor current amplitudes by >90% and resulted in retention of the mutated receptors in the endoplasmic reticulum. This forward trafficking domain is the first such identified for kainate receptors.
Fatal and non‐fatal machine‐related injuries suffered by children in Alberta, Canada, 1990–1997
Authors: Lim Gerald W. , Belton Kathy L. , Pickett William , Schopflocher Donald P. , Voaklander Donald C.
Published: January 2004

Background

Children raised on farms are exposed to many hazardous types of machinery. The objective of this study was to describe the magnitude of non‐fatal and fatal farm machinery injuries in Alberta children and adolescents (0–17 years) for the years 1990–1997. To date, there have been no published studies of pediatric farm injuries in Western Canada.

Methods

Data were collected through the Canadian Agricultural Injury Surveillance Program (CAISP). Death certificates and hospital charts were audited to provide enhanced information about the circumstances of injuries related to farm machinery for farm persons aged 17 years and younger.

Results

A total of 302 farm machinery injuries were recorded for the years 1990–1997. Of these, 14 resulted in death. All‐terrain vehicles (ATVs) were the most common cause of injury (n = 76), followed by tractors (n = 72), and power take‐offs (n = 15). The predominant injury mechanism was entanglement (n = 69), followed by falls from machines (n = 57), and being pinned/struck by a machine (n = 49). The median length of hospital stay for injuries was 2.0 days. Males (median = 2.0 days) had significantly longer hospital stays than females (median = 1.0 days). There were significantly more injuries reported during the summer and autumn than during the winter and spring. Those injured in the autumn were significantly older (median = 13.0 years) than children injured in the spring (median = 9.0 years). Injury rates dropped significantly during the study period from 119.9/100,000 per year in 1990 to 50.7/100,000 in 1997.

Conclusions

While injury rates have dropped, the number of injuries occurring to children on Alberta farms is of concern. The large number of ATV related injuries suggests that preventative strategies need to be focused in this area. Am. J. Ind. Med. 45:177–185, 2004. © 2004 Wiley‐Liss, Inc.
Work‐related carpal tunnel syndrome (WR‐CTS) in Massachusetts, 1992–1997: Source of WR‐CTS, outcomes, and employer intervention practices
Authors: Wellman Helen , Davis Letitia , Punnett Laura , Dewey Robin
Published: January 2004

Background

The Massachusetts Sentinel Event Notification System for Occupational Risks (MASS SENSOR) receives reports of work‐related carpal tunnel syndrome (WR‐CTS) cases from (1) workers' compensation (WC) disability claims for 5 or more lost work days; and (2) physician reports (PR).

Methods

From 1992 through 1997, 1,330 WC cases and 571 PR cases completed follow‐back surveys to provide information on industry, occupation, attributed source of WR‐CTS, outcomes, and employer intervention practices.

Results

Sixty‐four percent of the respondents had bilateral CTS and 61% had surgery, both of which were proportionally more frequent among WC cases. Office and business machinery was the leading source of WR‐CTS (42% of classifiable sources) in every economic sector except construction, followed by hand tools (20%). Managers and professional specialty workers were the most likely to report employers' interventions and were up to four times more likely to report equipment or work environment changes than higher risk groups.

Conclusions

State‐based surveillance data on the source of WR‐CTS provided valuable information on how and where to implement interventions. New occurrences of WR‐CTS are likely, especially in the highest risk industries where very few cases reported primary prevention measures (e.g., changes to equipment or work environment) implemented by their employers. Am. J. Ind. Med. 45:139–152, 2004. © 2004 Wiley‐Liss, Inc.
Review of the Federal Child Labor Regulations: Updating hazardous and prohibited occupations
Authors: Miller Mary E. , Bush Diane
Published: January 2004

Background

Child labor regulations are intended to protect our young and most vulnerable workers. While regulations are not the only strategy for providing a safe and healthy work environment for young workers, they are the first step in setting the community standard to protect them. The world of work has changed since the first child labor laws were issued in 1939. The U.S. Department of Labor (DOL) enlisted assistance from the National Institute for Occupational Safety and Health (NIOSH) to evaluate the current list of hazardous and prohibited occupations and to make recommendations for changes to the regulations.

Methods

A group of national experts reviewed the recommendations made by NIOSH. The consensus review process identified areas of agreement, disagreement, and priorities for the DOL's Wage and Hour Division. Gaps in the hazardous orders not addressed in the recommendations were also identified.

Results

This commentary describes the background of the Hazardous Orders under the Fair Labor Standards Act, the evaluation by NIOSH, the process used to review it, and recommendations for further action.

Conclusions

The NIOSH report is a valuable resource for anyone working to prevent occupational injuries—among adult and young workers alike. It is crucial that the DOL use the guidance provided by NIOSH and the Young Workers Safety and Health Network to improve the protections for young workers. Am. J. Ind. Med. 45:218–221, 2004. © 2004 Wiley‐Liss, Inc.
Osteoarthritis of the hip joint and farm work
Authors: Thelin Anders , Vingård Eva , Holmberg Sara
Published: January 2004

Background

Different types of farming and farm work were studied in relation to the occurrence of osteoarthritis of the hip joint in a cohort of farmers.

Methods

A group of 427 farmers with hip joint osteoarthritis were identified together with a matched control group of farmers without hip or knee problems. All were invited to an interview and physical examination. After a dropout of 10%, and removing those who had had predisposing diseases or trauma, the observations for 369 pairs were available for analyses.

Results

Farmers with larger dairy and swine confinement operations (sows) had an increased risk of acquiring osteoarthritis of the hip. In a logistic regression multivariate model, those who milked more than 40 cows daily had an increase in risk (OR = 4.5, 95% CI 1.9–11.0) in relation to those who did not work in dairy production. Those who had worked more than 5 hr daily in animal barns over a long period of time also had an increase in risk (OR = 13.3, 95% CI 1.2–145.0) in relation to those who did not work with animals. In another model, those who had large farm areas (>100 ha) had a significantly decreased risk (OR = 0.14, 95% CI 0.05–0.43) in relation to those who had smaller farm areas.

Conclusions

Farmers operating farms with large plant production area and few animal contacts had a significantly lower risk of incurring osteoarthritis of the hip than did farmers in general. The presence of animal production showed a significant positive relationship to the risk of developing hip joint osteoarthritis. Am. J. Ind. Med. 45:202–209, 2004. © 2004 Wiley‐Liss, Inc.
High prevalence of silicosis among stone carvers in Brazil
Authors: Antão Vinícius Cavalcanti dos Santos , Pinheiro Germania Araujo , Kavakama Jorge , Terra‐Filho Mário
Published: January 2004

Background

In the city of Petrópolis, Brazil, artisans carve souvenirs from a variety of silica‐containing minerals. The finding of pulmonary massive fibrosis in one of the workers motivated an investigation of the prevalence of silicosis in this group.

Methods

Between January 2000 and June 2002, a cross‐sectional study was performed. We obtained clinical and occupational histories, spirometry, lung volumes, and carbon monoxide diffusion capacity measurements. Chest radiographs and high‐resolution computed tomographies (HRCT) were evaluated. Personal air samples were analyzed.

Results

Forty‐two stone carvers were examined. The prevalence of silicosis was 53.7%. HRCT better characterized silicotic lesions compared to chest radiographs. Early coalescence of small opacities was associated with lung function impairment. The concentration of dust exceeded permissible limits in 91% of the workplaces.

Conclusions

Exposure to high levels of silica dust was associated with an increased prevalence of silicosis among stone carvers. Am. J. Ind. Med. 45:194–201, 2004. © 2004 Wiley‐Liss, Inc.
Enhancement of phenolic polymer properties by use of ethylene glycol as diluent
Authors: Singh K. P. , Palmese G. R.
Published: January 2004

One application of phenolic resins is for the inner lining of multilayered composites in fire critical applications. Typically such resins contain water as a diluent to facilitate injection and mold filling. Although water is effective in controlling the viscosity, its evaporation from the resin during cure has been found to cause microvoids in the cured resin that are 8–10 μm in size. These voids are believed to affect the properties of the final product. In addition to the initial water content, evolution of water also takes place as a result of cure. In this study, we investigated the effects of processing parameters such as cure temperature, postcure temperature, catalyst concentration, and the use of ethylene glycol as a replacement diluent on water loss, microvoid distribution, and consequently, the mechanical properties. Weight loss during cure was followed by using a thermogravimetric analyzer (TGA). Scanning electron microscopy (SEM) was used to obtain images of cured resin showing the microvoids. The properties that have been obtained for comparison are density, flexural modulus and strength, and fracture toughness. It has been shown that modification of the resin by removing the initial water of a commercial resin system and adding ethylene glycol as a replacement has the most significant effect on the microvoids as well as the properties of the polymer. A decrease in void content and increase in density along with a significant improvement in flexural modulus and fracture toughness have been observed upon replacement of water with ethylene glycol. This is significant because of the importance of the phenolic layer to the overall mechanical performance of a hybrid composite. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3096–3106, 2004
Effect of surface treatment on the mechanical properties of glass fiber/vinylester composites
Authors: Park Rohchoon , Jang Jyongsik
Published: January 2004

To study the effect of surface treatment on the mechanical properties of glass fiber/vinylester composites, glass fiber was surface‐treated with polybutadiene (PB), γ−methacryloxypropyltrimethoxysilane (γ‐MPS), and γ‐MPS‐modified polybutadiene (PB/γ‐MPS). The relationship between the interfacial strength and the impact strength of glass fiber/vinylester composites was also examined. PB/γ‐MPS was synthesized as a new surface modifier. PB/γ‐MPS‐treated composites exhibited the optimum concentration at which the flexural strength and the interlaminar shear strength (ILSS) were maximized. This was related to the role of PB/γ‐MPS in three interphase regions between the fiber and the matrix. Considering the relationship between the interfacial strength and the impact strength of the composites, the propagation energy and total energy showed a different trend in three regions. In region A, the propagation energy and total energy increased with an increasing shear strength, indicating that the adequate interfacial strength was required for improving the impact strength of the composites. In region B, the propagation energy and total energy decreased with an increasing shear strength. Most of impact energy was absorbed through fiber pullout and delamination. In region C, the fiber breakage was the dominant failure mode of the composites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3730–3736, 2004
Modification of non‐Newtonian flow behavior of aqueous solution of poly(vinyl alcohol) by conducting polypyrrole prepared by in situ polymerization of pyrrole
Authors: Ghosh Premamoy , Kar Swarnendu B.
Published: January 2004

The rheological behavior of an aqueous solution of poly(vinyl alcohol) (PVA) and polypyrrole (PPY) dispersions prepared by ferric chloride (FeCl3)‐catalyzed polymerization of pyrrole was investigated at 12°C using a coaxial rotational viscometer. The results show that the addition of a low dose of FeCl3 to the PVA solution greatly influences its rheology. The prominent shear‐thickening (dilatant) nature of PVA turns significantly pseudoplastic (shear thinning) in the presence of FeCl3. Polypyrrole‐loaded PVA was obtained in a stable, optically clear dispersion by in situ polymerization of pyrrole in an aqueous PVA solution (5%) using FeCl3 as the oxidative catalyst at 12°C. The PPY dispersions in aqueous PVA systems having a low loading of PPY and low Fe+3 content retain the dilatant character of an aqueous PVA solution; however, for an aqueous PVA system having a relatively high PPY loading and also a high Fe+3 content, prominent pseudoplastic (shear thinning) behavior is exhibited. The odd novel rheological patterns exhibited by a PVA solution in the absence and presence of FeCl3 and the PVA–PPY dispersions containing FeCl3 under different sets of conditions are explained on the basis of the complexation of PVA by Fe+3 and related ions and also as a consequence of some degree of H‐bonding and chemical grafting between the support polymer PVA and the PPY formed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3737–3741, 2004
Friction welding of similar materials: Polypropylene, high‐density polyethylene, and nylon‐6
Authors: Lin Ching‐Bin , Wu Li Cheng , Chen Yu Yao
Published: January 2004

The effects of spin‐friction pressure and timing on the friction welding between parts of the same materials, PP, HDPE, and nylon‐6, are discussed. The heat‐affected zone is divided into three regions: the plasticized region (Zpl), the partly plasticized region (Zpd), and the undeformed region (Zud). The tensile fracture morphology has three main sections: the nonplasticized central section (Fud), the plasticized peripheral section (Fpl), and the partly plasticized section between Fud and Fpl (Fpd). Friction pressures (spinning timing) of 1.17 MPa (16 s) in PP–PP welding, 1.77 MPa (8 s) in HDPE–HDPE welding, and 0.98 MPa (8, 10, and 12 s) in nylon‐6–nylon‐6 welding attains better bonding strength because their components have larger Fpd and Fpl regions, which have no Fud in the central part. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2771–2780, 2004
Fractal kinetics of radical polymerization of dimethyl diallyl ammonium chloride
Authors: Koslov G. V. , Malkanduev Yu A. , Zaikov G. E.
Published: January 2004

The proposed technique allows determination of variation in a macromolecular coil structure of dimethyl diallyl ammonium chloride, characterized by its fractal dimension, during polymerization. It is shown that this one factor, unaccounted for in conventional theories, determines the most important characteristics of a polymerization process: rate, output of a finite product, and molecular weight. Further, the methods of fractal kinetics allow the quantitative description of synthesis of polymers and, in particular, give the correct shape of the conversion degree–time kinetic curve. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3140–3143, 2004
Reaction kinetics modeling and thermal properties of epoxy–amines as measured by modulated‐temperature DSC. I. Linear step‐growth polymerization of DGEBA + aniline
Authors: Swier Steven , Van Assche Guy , Van Mele Bruno
Published: January 2004

A mechanistic approach including both reactive and nonreactive complexes can successfully simulate both nonreversing (NR) heat flow and heat capacity (Cp) signals from modulated‐temperature DSC in isothermal and nonisothermal reaction conditions for different mixtures of diglycidyl ether of bisphenol A + aniline. The reaction of the primary amine with an epoxy–amine complex initiates cure (E1A1 = 80 kJ mol−1), whereas the reactions of the primary amine (E1OH = 48 kJ mol−1) and secondary amine (E2OH = 48 kJ mol−1) with an epoxy–hydroxyl complex are rate determining from about 2% epoxy conversion on. The reliability of the proposed mechanistic model was verified by experimental concentration profiles from Raman spectroscopy. When cure temperatures are chosen inside or below the full cure glass‐transition region, vitrification takes place partially or completely, respectively, as can be concluded from the magnitude of the stepwise decrease in Cp. The effect of the epoxy conversion (x) and mixture composition on thermal properties such as the glass‐transition temperature (Tg), the change in heat capacity at Tg [ΔCp(Tg)], and the width of the glass transition region (ΔTg) are considered. The Couchman relationship, in which only Tg and ΔCp(Tg) of both the unreacted and the fully reacted systems are needed, was evaluated to predict the Tg– x relation by using simulated concentration profiles. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91:2798–2813, 2004
Novel method of preparing microporous membrane by selective dissolution of chitosan/polyethylene glycol blend membrane
Authors: Zeng Minfeng , Fang Zhengping , Xu Chengwei
Published: January 2004

Chitosan membranes with high porosity and good mechanical properties were prepared by selective dissolution of the blend membranes of chitosan (CS) and polyethylene glycol (PEG). The morphology of the obtained porous membranes was characterized by scanning electron microscopy. The pore size changed from 500 nm to several micrometers, depending on the molecular weight of the PEG used. The water permeability of the porous membrane depends on both the pore size and the porosity, except in the case of PEG2000, in which a higher molecular weight of PEG was used, producing greater water permeability. The tensile strength of the porous membranes obtained by this method was higher in both the wet and the dry state than that of the porous chitosan membranes prepared by using silica particles as porogen. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2840–2847, 2004
Aluminum powder filled nitrile rubber composites
Authors: Vinod V. S. , Varghese Siby , Kuriakose Baby
Published: January 2004

Effect of aluminum powder on the properties of nitrile rubber (NBR) composites and the role of bonding agent viz. hexamethylene tetramine‐resorcinol has been investigated. Shore A hardness of the aluminum powder filled composites is lower than that of high abrasion furnace (HAF) and acetylene black (ACB) filled nitrile rubber composites and can be increased by the addition of bonding agent. Equilibrium swelling decreased considerably by the use of hexamethylene tetramine‐resorcinol, suggesting an improved nitrile rubber–aluminum powder adhesion. A marked increase in thermal conductivity is obtained with the incorporation of aluminum powder. Increased thermal conductivity reduced the additional time needed for the vulcanization of thick rubber articles and imparted uniform curing throughout the material. In nitrile rubber, the modulus and tensile strength followed the order HAF > ACB > aluminum powder. Combination of HAF and aluminum powder in NBR gave composites with good thermal conductivity and mechanical properties. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3156–3161, 2004
Synthesis and kinetic studies of UV‐curable urethane‐acrylates
Authors: Hsieh K. H. , Kuo C. H. , Dai C. A. , Chen W. C. , Peng T. C. , Ho G. H.
Published: January 2004

The UV‐curable urethane‐acrylates based on 2‐hydroxyethyl methacrylate (HEMA)‐terminated polyurethane (PU) for lithographic and coating applications are investigated in this study. Series of PU prepolymers were made from 4,4‐diphenyl methane diisocyanate (MDI), poly(propylene oxide) glycol (PPG 400), poly(butylene adipate)glycol (PBA 500), or poly(tetramethylene oxide) glycol (PTMO 1000) and are terminated with HEMA. The 2,2‐azobisisobutyronitrile (AIBN) was used as a UV‐initiator under air atmosphere. The curing kinetics of HEMA‐terminated PU film were studied. The curing analysis, using FTIR and reaction kinetics, indicate the reaction rate equation correlates well with the film thickness [T], initiator concentration [I], unreacted double bond concentration [CC], and exposed energy [E] of the reaction system. The kinetic rate equation for the UV‐curable reaction can be written as

equation image

© 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3162–3166, 2004
Effects of thermal aging on chemical–physical and electrical properties of poly(propylene terephthalate)
Authors: Saccani Andrea , Motori Antonio , Sisti Laura , Lotti Nadia
Published: January 2004

Poly(propylene terephthalate) (PPT) was subjected to aging at high temperatures (150–190°C) in air and some mechanical (impact strength), physical (weight loss), and electrical (dc conductivity and ac electrical strength) properties were determined as a function of aging time and temperature. Some chemical–physical characteristics (such as the average molecular weight, the carboxyl end‐group content, and crystallinity degree) were investigated during the degradation process, as well. From the collected data, the thermal endurance parameters (i.e., the temperature index and the halving interval), which are key parameters in the determination of materials reliability and design of electrical insulating system, were derived according to IEC 216 Standard, and compared with those relevant to other thermoplastic polyesters. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2848–2854, 2004
Numerical modeling of the dynamic tensile behavior of irregular fibers
Authors: He Wendy W. , Wang Xungai
Published: January 2004

Most fibers are irregular and are often subjected to rapid straining during mechanical processing and end‐use applications. In this article, the effect of fiber dimensional irregularities on the dynamic tensile behavior of irregular fibers was examined using the finite‐element method (FEM). Fiber dimensional irregularities are simulated with sine waves of different magnitude (10, 30, and 50% level of diameter variation). The tensile behavior of irregular fibers was examined at different strain rates (333, 3333, and 30,000%/s). The breaking load and breaking extension of irregular fibers at different strain rates were then calculated from the finite‐element model. The results indicate that strain rate has a significant effect on the dynamic tensile behavior of an irregular fiber, and that the position of the thinnest segment along the fiber significantly affects the simulation results. Under dynamic conditions, an irregular fiber does not necessarily break at the thinnest segment, which is different from the quasi‐static results. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2855–2861, 2004
Electric studies on polyvinyl alcohol with additions of magnesium sulfate
Authors: Mansour A. B.
Published: January 2004

Polyvinyl alcohol (PVA; molecular weight 17,000 g/mol) with additions of several different amounts of magnesium sulfate (molecular weight 246.945 g/mol) was prepared by the casting technique. The dc electric properties of these films were measured in different temperature ranges and the activation energy values as a function of different magnesium sulfate amounts were calculated. The dependency of dc electrical conductivity σdc at a certain temperature was found to fit the well‐known equation σdc = [(1/R) × (t/A)] (Ω−1 m−1). The temperature dependency of σdc, which suggested an electronic hopping conduction mechanism in a thermally assisted electric field, in addition to some theoretical mechanism were discussed. Also the values of activation energy as a function of different amounts of magnesium sulfate were investigated and it was found that the activation energy values for most samples increase with increased amounts of magnesium sulfate. On the other hand, the nonlinear coefficient parameter as a function of the different amounts of magnesium sulfate was investigated for all the prepared samples. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3167–3173, 2004
Predication of critical distance of wall‐slip phenomenon during extrusion of carbon black‐filled natural rubber/cis‐polybutadiene rubber compound
Authors: Liang Ji‐Zhao
Published: January 2004

The wall‐slip phenomenon during extrusion of polymer fluids is an important characteristic of viscoelasticity. The wall‐slip behavior and the factors affecting it for natural rubber (NR)/cis‐polybutadiene rubber (BR) filled with carbon black compound were investigated by using a Monsanto processability tester in a temperature range of 90–130°C and at shear rates that varied from 50 to 103 s−1. Under simplified supposition conditions, a mathematical model for description of the relationship between pressure variation, polymeric properties, and extrusion operation parameters when wall‐slip phenomenon occurs was established by using a tensor analysis method. On the basis of this model, an equation for estimation of critical slip distance (or position) was derived. The results showed that the measured critical pressure drop, when wall‐slip begins to occur, was consistent with the theoretical predictions. The wall‐slip phenomenon of the sample happened near the exit of the die. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3239–3243, 2004
Glass‐transition temperature in the curing process of bismaleimide modified with diallylbisphenol A
Authors: Boey F. , Xiong Y. , Rath S. K.
Published: January 2004

The Tg‐conversion relationship, during the thermal curing of different stoichiometric formulations of 1,1′‐(methylene‐di‐4,1‐phenylene) bismaleimide (BMI), modified with o,o′‐diallyl bisphenol A (DABA), was investigated. The DiBenedetto equation was used to model this relationship for the formulation of DABA‐1 (BMI : DABA, 1 : 1). Based on this model, the Tg‐conversion relationship of formulation DABA‐0.5 (BMI : DABA, 1 : 0.5) was modeled. The high consistency between the model curve and experimental data showed that the change of Tg, attributed to copolymerization between BMI and DABA in DABA‐0.5, in the low‐conversion regime, was the same as that in DABA‐1. This also verifies that, for the formulation DABA‐0.5, copolymerization and homopolymerization do not overlap with each other. The reactions progressed sequentially and homopolymerization occurred after completion of copolymerization. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3244–3247, 2004