bluuebunny/crossref_metadata_2025 huggingface dataset:
In situ thermoset molecular composites
Authors: Wiff D. R. , Lenke G. M. , Fleming P. D.
Published: April 2003

The polymerization of rigid rod polymer precursors in a reactive matrix precursor, which is later cured in the mold, constitutes the in situ process. A poly‐azomethine (PAM) was used as the rigid rod molecule. The resin used was an epoxy. We discuss the prediction of mechanical properties using micromechanics equations for chopped fiber composites. The chemistry used to synthesize the rigid rod polymer PAM in the epoxy precursor is reviewed. Approaches to better control the cure of these epoxy systems through cure kinetics and cure rheology studies completes the thermoset in situ molecular composite process. There was a 71% increase in tensile modulus in comparison to that of the neat epoxy resin. Molecular modeling simulations and continuum mechanics are used to help understand these findings. PAM/epoxy systems were used as a matrix material in the fabrication of unidirectional glass fiber/(PAM/epoxy) structural composites. © 1994 John Wiley & Sons, Inc.
Ion irradiation of poly(methyl methacrylate) for precise control of electrical and optical properties
Authors: Congedo T. V. , Schoch, Jr. K. F.
Published: April 2003

Ion irradiation with Xe+ has been utilized to produce electrical conductivity in PMMA, as measured using a four‐point in‐line probe. Incident ion beam energy and current density have been varied to investigate their effect on electrical conductivity and optical absorbance of the samples after irradiation. Results support the premise that selection of beam parameters that maximize the ratio of energy transfer‐producing displacements to energy transfer‐producing ionization maximizes the ratio of induced conductivity to induced absorbance in the irradiated samples. Conductivity versus ion dose has also been shown to be well estimated using a damage trial model. © 1994 John Wiley & Sons, Inc.
Rapid mechanical deformation of poly(ethylene terephthalate) fibers at temperatures above the glass transition
Authors: Hristov H. A. , Hearle J. W. S. , Schultz J. M. , Kennedy A. D.
Published: April 2003

The mechanical properties of poly(ethylene terephthalate) (PET) fibers at temperatures above the glass transition are investigated by means of a specially constructed device. Measurements of the deformation rate and of the “dynamic” stress‐strain curves of the fibers are performed in nearly isothermal regime (after initial rapid heating) in a temperature interval 100–200°C. The results reported in the present work demonstrate that the high‐temperature mechanical characteristics of rapidly crystallizing polymers can be deduced to a satisfactory precision, while keeping the crystallinity development at low level. Our investigations indicate that if the high‐temperature deformation is sufficiently fast, the polymer behavior is similar to the deformation at sub‐Tg temperatures. Based on this similarity, a qualitative model of the deformation in the high‐temperature region is proposed. The proposed model is fundamentally equivalent to the models describing mechanical deformation of glassy polymers at temperatures below the glass transition. ©1995 John Wiley & Sons, Inc.
Molecular interpretation of miscibility in polyamide‐6 blends with alkali ionomers of sulfonated polystyrene
Authors: Rajagopalan Padmavathy , Kim Joon‐Seop , Brack Hans Peter , Lu Xinya , Eisenberg Adi , Weiss R. A. , Risen William M.
Published: April 2003

Blends of polyamide‐6 with lithium ionomers of 9.8 and 5.4 mole percent sulfonated polystyrene, formed by combining solutions of these polymers, are miscible over a wide compositional range, but those with the equivalent sodium ionomers are not. The molecular origin of this difference is addressed by studying the far infared and infrared spectra of the blends and pure materials to follow changes in the interactions between the cations and their surroundings, and changes in the interactions between functional groups. Based on analysis of these spectra, a molecular level interpretation of the blending is proposed. The initial step involves both the interaction of one amide carbonyl with an Li+ ion and simultaneous hydrogen bonding between an amide NH and a sulfonate group. This eventually leads to formation of an Li(>CO)+n(n ∼ 4) entity while the sulfonates are converted to the acid form through hydrogen bonding to the amide NH groups. The Na+ ion does not interact strongly enough with the amide groups to leave its sulfonate environment to a significant extent. © 1995 John Wiley & Sons, Inc.
Solvent‐induced crystallization of nylon‐6I
Authors: Liu Wu , Breault Brigitte , Brisson Josee
Published: April 2003

The ability of various hydrogen bond‐forming solvents to induce crystallinity in nylon‐6I was studied using DSC, FTIR spectroscopy, and x‐ray diffraction. Comparison was made with predictions using the solubility parameter, which is related to possibilities of interaction formation. General predicted tendencies agreed with experimental results, in agreement with proposed influence of solvent‐polymer interactions in the solvent‐induced crystallization process. FTIR investigation of polymers treated with methanol and methanol‐d shows that polymer segments forming hydrogen bonds with solvent molecules crystallize preferentially. It is therefore concluded that hydrogen bond exchanges with the solvent favor chain rearrangements leading to crystallization. © 1995 John Wiley & Sons, Inc.
A detailed study of the viscoelastic nature of vapor sorption and transport in a cellulosic polymer. I. Origin and physical implications of deviations from Fickian sorption kinetics
Authors: Sanopoulou M. , Roussis P. P. , Petropoulos J. H.
Published: April 2003

Various aspects of the kinetics of sorption of acetone vapor by cellulose acetate films at 30°C have been studied in detail, the principal aim being to understand more thoroughly the physical nature and causes of non‐Fickian behavior in this and other similar polymer‐micromolecular penetrant systems. Particular attention was given to the changes in sorption (including absorption, desorption, and resorption) kinetics caused by (a) systematic variation of the vapor pressure of acetone in different ways and (b) changes in membrane thickness. It has been shown that both viscous volume swelling relaxation and longitudinal differential swelling stress effects must be invoked, in order to explain fully the observed behavior. Detailed analysis of two‐stage sorption kinetics indicated (1) reasonable agreement between estimates of the diffusion coefficient reported by different authors, as long as a consistent analysis of the first stage is used, although the significance of the values given is open to some doubt, because the said first stage is found not to be free of non‐Fickian features; and (2) reasonable conformity of the second stage to a first‐order volume relaxation process (except a long times), with a relaxation frequency strongly dependent on the width of the concentration interval covered by the sorption experiment (and hence on the applied “osmotic stress”). The close similarity of second‐stage sorption to nonlinear viscoelastic creep behavior, previously found in the cellulose‐water system was confirmed and is taken further here, by demonstrating semiquantitative agreement between the corresponding “elastic swelling” and mechanical bulk moduli. ©1995 John Wiley & Sons, Inc.
Molecular structure refinement of a segmented thermotropic polyester containing an aromatic triad mesogen
Authors: Carotenuto Maurizio , Guadagno Liberata , Iannelli Pio , Chiellini Emo , Farah Abdiaziz Ali , Galli Giancarlo
Published: April 2003

The polymorphic behavior of a polyester consisting of an aromatic triad mesogen and a flexible spacer has been investigated. The effect of thermal and mechanical treatment on the appearance of two crystalline phases stable at room temperature is discussed. The molecular packing (triclinic cell, space group P1) and the morphological parameters of the crystalline phase stabilized by drawing process are evaluated and refined. The whole‐pattern method, based on the analysis of the whole x‐ray diffraction pattern from fiber samples of polymer, has been employed. The molecular packing resembles very much that of polyethylene terephthalate. ©1995 John Wiley & Sons, Inc.
Dilute solution properties of poly(dimethyldiallylammonium chloride) in aqueous sodium chloride solutions
Authors: Xia Jiulin , Dubin Paul L. , Edwards Shun , Havel Henry
Published: April 2003

MW fractions of poly(dimethyldiallylammonium chloride) (PDMDAAC) were prepared by preparative size‐exclusion chromatography and characterized by static and dynamic light scattering, viscometry, size‐exclusion chromatography, and electrophoretic light scattering, in 0.50M NaCl solution. The behavior of fractions with MW < 2 × 105 was as expected for a strong polyelectrolyte in a good solvent, with a Mark‐Houwink exponent of ca. 0.8, and MW‐dependencies of the hydrodynamic radius and the radius of gyration of corresponding magnitude. At higher MW, curvature appears in the MW‐dependencies, which can be best explained by the presence of branching. While this notably lowers the intrinsic viscosity at high MW, the electrophoretic mobility is unchanged regardless of molar mass. Thus, the branched polymers display the electrophoretic free‐draining behavior characteristic of linear polyelectrolytes. ©1995 John Wiley & Sons, Inc.
The application of a Gauss‐Eyring model to predict the behavior of thermoplastics in tensile experiments
Authors: Haward R. N.
Published: April 2003

The Gaussian expression for the isothermal tensile deformation of thermoplastics including the proposed strain hardening constant Gp, has been combined with the Eyring flow equation to provide a new relation describing the rate of strain of a thermoplastic in terms of the true stress and the extension ratio under isothermal conditions. In conventional mechanical tests this model can be used to quantify the tendency to strain localization, to predict the natural draw ratio and the inversion point where the true engineering stress passes through a minimum. The latter is expected to correlate with the value of the extension ratio where crazes do not propagate under tension. The equation is most easily demonstrated in constant load experiments where they agree well with published work. However, for a more precise evaluation of the theory the constant Gp should be measured separately and the calculated results compared with other tests on the same material. Where necking occurs it is possible to use a simplified plug flow model to calculate neck profiles. These show that no special assumptions are required to account for necking which results directly from the interaction of geometric thinning and strain hardening, even where true strain softening is absent. The procedure makes it possible to illustrate the way in which the form of the neck can be affected by the rate of extension or in a constant load experiment by the applied load. ©1995 John Wiley & Sons, Inc.
NMR relaxation study of thermal degradation in cured PMR polyimides
Authors: Bradley D. S. , Von Meerwall E. D. , Roberts G. D. , Kamvouris J.
Published: April 2003

We have studied cross‐linking and thermal degradation of high‐performance first‐and second‐generation PMR‐15 polyimides, both thermoset and thermoplastic versions, by performing nonspectroscopic NMR solid echo T*2 relaxation measurements at temperatures up to 430°C using probes built for this purpose. We employ signal averaging and automated decomposition of the relaxation decays into two Gaussian components, the slower of which gradually appears above 300°C. Tracking the molecular mobility spectrum in terms of the relative intensity of the components and their relaxation times as temperature is cycled, we detect essentially no irreversible effects below the glass transition, measure permanent mobility reductions attributable to completion of cure, and find that exposure to temperatures above 380°C on the order of 1 h is required for substantial thermal degradation to occur. These results are closely supported by thermal and mechanical measurements on parallel specimens. Second‐generation PMR resins appear to have higher microscopic rigidity and reduced viscous fraction at high temperatures. ©1995 John Wiley & Sons, Inc.
Determination of optimized blending fractions for particle size distributions or molecular weight distributions involving various physical properties
Authors: Sudduth Richard D.
Published: April 2003

It has been shown in this study that the effects of particle size distribution or molecular weight distribution on selected physical properties can be related by a generalized blending approach that involves similar equations. The blending equations developed involve different z‐fractions where z = 3 for volume blending of spherical particles, or z = 2 for surface blending of spherical particles, or z = 1 for the weight blending of molecular weights. This new analysis approach addresses the magnitude of the ratios of particle size averages, Dx/Dy, or ratios of molecular weight averages, Mx/My, as well as the location of this maximum, the level of distribution information available for the starting materials, and the type of z‐fraction blending. To illustrate this approach suspension viscosity/concentration data was used to show how the Dx/Dy ratio could be introduced successfully to analyze latex volume blending where z = 3. In addition, the maximum steady‐state elastic compliance, Je, as a function of weighted blends (z = 1) of two different molecular weights of polyisobutylene was shown to fit the simple equation Je = 1.187 (M3/M2) (M4/M1) reasonably well. © 1995 John Wiley & Sons, Inc.
Effect of solution concentration on the gelation of aqueous polyvinyl alcohol solution
Authors: Liu Mingzhu , Cheng Rongshi , Qian Renyuan
Published: April 2003

The concentration dependence of cryogenic gelation for aqueous solution of poly(vinyl alcohol) was studied by measuring the apparent gel fraction G and the swelling ratio Q of the gel formed by freezing and thawing. It was found that for the gelation process there were three distinct regions of solution concentration bounded by two concentrations Cgel and C. The gel started to form at C = Cgel, while no visible gel could be detected even upon repeated freezing and thawing of the extremely dilute solutions of C < Cgel. The entire solution was gelatinized as a whole in the high concentration region of C > C. In the intermediate concentration region, Cgel < C < C, which covers three orders of magnitude in concentration, gel and sol phases coexist. Both concentration dependencies of G and Q show two branches jointed at a concentration very close to the overlap concentration C*. The curve of GċQ versus C shows a sharp cusp. In case the sharp cusp concentration is really the value of C*, gelation offers a precise method to determine the overlap concentration. ©1995 John Wiley & Sons, Inc.
Morphology of nylon 6/polypropylene blends compatibilized with maleated polypropylene
Authors: González‐Montiel A. , Keskkula H. , Paul D. R.
Published: April 2003

Transmission electron microscopy (TEM) was used to examine the morphology of blends of nylon 6 and polypropylene (PP) containing various maleated polypropylenes (PP‐g‐MA). The size of the dispersed polypropylene particles decreases as the content of maleic anhydride in the PP‐g‐MA increases for binary blends of nylon 6 and the maleated polypropylenes. Ternary blends of nylon 6, PP, and PP‐g‐MA show morphologies that depend on the content of maleic anhydride of the PP‐g‐MA and on the miscibility of PP and PP‐g‐MA. Blends where PP and PP‐g‐MA are immiscible show a bimodal distribution of particle sizes. Miscibility of the PP and PP‐g‐MA was determined by TEM using a special staining technique. Experimental observations of miscibility were further corroborated by thermodynamic calculations. The morphology of the ternary blends was also found to be dependent on the ratio of PP/PP‐g‐MA. By changing this ratio it was possible to induce drastic changes of morphology, going from a continuous nylon 6 phase to a continuous PP phase at a fixed composition. The mechanical properties of these blends were found to be dependent on their morphology. ©1995 John Wiley & Sons, Inc.
Hydrodynamic properties of model 3‐miktoarm star copolymers
Authors: Iatrou Hermis , Siakali‐Kioulafa E. , Hadjichristidis Nikos , Roovers Jacques , Mays Jimmy
Published: April 2003

The synthesis of well‐defined, nearly monodispersed, 3‐miktoarm (from the greek word μlkτós meaning mixed) star copolymer of the A2B type is described. A and B is either polystyrene (PS), polybutadiene (PBd), or polyisoprene (PI). The sequential controlled addition of living anionic B and A chains to methyltrichlorosilane leads to narrow molecular weight distribution miktoarm star copolymers with homogeneous composition. Characterization was carried out by size exclusion chromatography, low‐angle laser light scattering, laser differential refractometry, membrane and vapor pressure osmometry, nuclear magnetic resonance and ultraviolet spectroscopy. Analysis of [η], RH and Rv of the A2B and one A2B2 miktoarm copolymers, suggests that a small expansion of the copolymer occurs either in a good solvent for both species or in a Θ solvent for one of them, as compared with the corresponding star homopolymers. This is in contrast to results obtained on linear block copolymers, and is due to the increased occurrence of heterocontacts in the miktoarm starshaped architecture. © 1995 John Wiley & Sons, Inc.
Scanning force microscopy and effective medium theory study of free‐standing polyaniline thin films
Authors: Porter T. L. , Minore D. , Stein R. , Myrann M.
Published: April 2003

The technique of scanning force microscopy was used to study the nanometer‐scale structure of NMP cast films of polyaniline. Noncontact mode images provide direct evidence that polyaniline prepared in this form is a granular conductor. The films were found to consist of micrograins whose size and density were determined by the pH of the acid solution used to protonate the films. At pH 7, the polyaniline films exhibited a mostly disordered structure, with small 2–10 nm particles visible. Protonation at pH 5 to pH 3 resulted in partial agglomeration of the primary particles into larger bundles, with sizes up to 75 nm. Treatment in solution pHs of 2 or less resulted in films consisting of close‐packed bundles of dimension 20–30 nm. The conductivity of the films exhibited a sharp rise beginning with protonation at pH 2 or less. Effective medium theory (EMT), was used to model the macroscopic conductivity of these films based on the SPM measured microscopic film structure. Using the size and size distribution of polymer micrograins or bundles in a modified EMT, we are able to obtain predicted conductivities that are close to the measured values for these films. © 1995 John Wiley & Sons, Inc.
Correlations between gas permeation and free‐volume hole properties probed by positron annihilation spectroscopy
Authors: Jean Y. C. , Yuan J.‐P. , Liu J. , Deng Q. , Yang Hsinjin
Published: April 2003

Free‐volume hole sizes, fractions, and distributions in a series of polycarbonate‐based polymers are measured by using positron annihilation lifetime (PAL) spectroscopy. Correlations between the obtained free‐volume hole properties and gas diffusion coefficients are observed. © 1995 John Wiley & Sons, Inc.
Physical aging of a polyetherimide: Creep and DSC measurements
Authors: Echeverria Isabel , Su Ping‐Chung , Simon Sindee L. , Plazek Donald J.
Published: April 2003

Creep and differential scanning calorimetry (DSC) measurements have been used to study the physical aging behavior of a polyetherimide. Isothermal aging temperatures ranged from 160°C to Tg with aging times ranging from 10 min to 8 days. The only measurable effect of physical aging on the short‐time creep curves is a shift of the creep compliance to longer times. Andrade plots of the compliance versus the cube root of time are linear at short times with the slope β decreasing with increasing aging time to a constant value once equilibrium is reached. Log β3 is related directly to the degree to which the creep curves shift to longer times with physical aging, and is used in this work as a measure of physical aging. A reduced curve of log β3 versus log aging time is obtained for the aging temperatures investigated by appropriate vertical and horizontal shifts. The enthalpy change during aging increases linearly with the logarithm of the aging time, ta, leveling off at equilibrium at values which increase with decreasing aging temperature. Hence, both nonequilibrium and equilibrium temperature shift factors can be calculated from the DSC data. Good agreement is observed between the equilibrium temperature shift factors obtained from the creep and DSC data. The temperature dependence of the nonequilibrium temperature shift factors is found to be an order of magnitude smaller than that of the equilibrium shift factors. The time scales to reach equilibrium for enthalpy and for mechanical measurements are found to be the same within experimental error. © 1995 John Wiley & Sons, Inc.
A meta‐analysis of the relationship between job satisfaction and employee health in Hong Kong
Authors: Cass Monica H. , Siu Oi Ling , Faragher E. Brian , Cooper Cary L.
Published: April 2003

A meta‐analysis was conducted of correlations between job satisfaction and measures of health for samples originating from Hong Kong. Using established procedures and a priori selection criteria, 22 samples were combined from published and unpublished sources, in a combined sample of 4492 workers from various industries and occupations. Results indicated relationships between job satisfaction and health for Hong Kong employees were high, and notably different from the larger sample in the HERMES study (Cass, Faragher & Cooper2003). The moderator analysis revealed that samples comprising an approximately equal gender mix had larger correlations than samples of mostly women, or mostly men. Our comparison of studies with differential methodological rigour indicated that this had a minimal impact on combined effect size. Copyright © 2003 John Wiley & Sons, Ltd.
Incorporating interpersonal events within hassle measurement
Authors: Maybery Darryl
Published: April 2003

The current studies sought to extrapolate previous findings regarding the importance of interpersonal events within hassle measurement. It did so by exploring the subscale structure of a comprehensive group of interpersonal and non‐interpersonal hassles. It then examined correlations between those components and with measures of distress and well‐being. The two studies were based on an item pool developed from prior research that had shown that interpersonal events were missing from a prominent hassle measure (Maybery & Graham, 2001). Principal component analyses and one‐factor congeneric models were used to examine the factor structures. The first study (n = 289) identified 13 hassle subscales. The second study (n = 457) incorporated additional course‐ and study‐related items from focus groups and interviews. In that study, the 13 subscales were replicated and two additional hassle factors were identified. The final 15 factors included eight interpersonal and seven non‐interpersonal subscales. Moderate correlations were found between some interpersonal and non‐interpersonal factors and correlations with commonly used distress and well‐being instruments showed a considerable number of weaker moderate relationships. In conjunction with previous research, the findings indicate that interpersonal events constitute additional hassle categories to non‐interpersonal events and the former may have independent associations within distress and well‐being models. Future research is necessary to determine if interpersonal events contribute to distress and well‐being independently of other hassles. Copyright © 2003 John Wiley & Sons, Ltd.
Stress and burnout in forensic psychiatric nursing
Authors: Happell Brenda , Pinikahana Jaya , Martin Trish
Published: April 2003

The relevant literature suggests that all branches of the nursing profession are subject to high levels of stress and burnout. Forensic psychiatric nursing has been considered as an area of high risk, despite a paucity of literature in this area, particularly in Australia. This paper presents the findings of a research study undertaken with forensic nurses (n = 51) and designed to measure their level of stress and burnout. The Maslach Burnout Inventory (MBI) and the Nursing Stress Scale (NSS) were the instruments used. The findings indicated that relatively few forensic nurses suffered from ‘high’ levels of burnout with considerably more forensic nurses recording ‘low’ levels of burnout. On the personal accomplishment subscale, only 17 per cent recorded a ‘high’ score. Interestingly the least reported stressor was lack of staff support for nursing activities which suggests that the amount of support received may account for lower than expected levels of stress. Copyright © 2003 John Wiley & Sons, Ltd.
Stress among national politicians elected to Parliament for the first time
Authors: Weinberg A. , Cooper C. L.
Published: April 2003

Previous research has shown that levels of stress among national politicians are higher than among workers in comparable management jobs. The election of 236 new Members of Parliament (MPs) in the 1997 UK General Election permitted longitudinal study. The General Health Questionnaire‐12 and Occupational Stress Indicator measured psychological and physical stress in comparable groups at pre‐election (T1; n = 29) or 3‐month post‐election (T2; n = 66) time‐points and at 1‐year follow‐up (T3; n = 66). Stress increased from T1 to T2 and was predicted by factors at the home–work interface (p < 0.001). Politicians in poor psychological health reported long working hours and no emotional support (p < 0.05). At T3 psychological symptoms returned to T1 levels, while physical stress remained elevated for male MPs, those with children and those in the party in Government (p < 0.05). Copyright © 2003 John Wiley & Sons, Ltd.
Suppressive effects of trihexyphenidyl on methamphetamine‐induced dopamine release as measured by in vivo microdialysis
Authors: Shimosato Kazuaki , Nagao Noriki , Watanabe Satoru , Kitayama Shigeo
Published: April 2003

Abuse of methamphetamine (MAP) and cocaine causes severe medical and social problems throughout the world. Our previous study found that trihexyphenidyl (THP), a muscarinic cholinergic receptor antagonist, specifically suppressed the rewarding properties of MAP but not of cocaine, as measured by conditioned place preference in mice. The present study examined using in vivo microdialysis whether THP differentially affects the extracellular dopamine (DA) levels in the nucleus accumbens and striatum of mice injected with MAP and cocaine in comparison with another antimuscarinic agent, scopolamine (SCP). In addition, locomotor activity was simultaneously measured during microdialysis. In vivo microdialysis experiments revealed that during the initial hour after injection of MAP (1 mg/kg) DA levels increased up to 698% in the nucleus accumbens and 367% in the striatum as compared to the basal level. These increases were reduced to 293% in the nucleus accumbens and 207% in the striatum by treatment with 5 mg/kg THP. However, SCP (3 mg/kg) had no effect on the increases in extracellular DA levels in both regions after MAP injection. Cocaine (10 mg/kg) increased DA levels during the initial hour to 254% in the nucleus accumbens and 220% in the striatum as compared to the basal level. These increases were unaffected by treatment with either THP or SCP. On the contrary, both THP and SCP enhanced the locomotor‐stimulant action of MAP and cocaine. These results, together with our previous finding, suggest that THP may specifically antagonize the rewarding properties of MAP through suppression of DA release in the mesolimbic area without retarding locomotor activity. Synapse 49:47–54, 2003. © 2003 Wiley‐Liss, Inc.
Synaptic nests lack glutamate transporters in the cochlear nucleus of the mouse
Authors: Josephson E.M. , Morest D.K.
Published: April 2003

Synaptic nests are closely packed collections of synaptic endings. Nests may be deficient in the glial processes which usually separate terminals in the CNS and which transport much of the glutamate associated with high levels of excitatory activity. We hypothesized that nests might lack glial glutamate transporters, but possibly would conserve neuronal glutamate transporter. Although present throughout the brain, nests are especially numerous in the cochlear nucleus. We performed immunoelectron microscopy by preembedding peroxidase and immunogold methods and by postembedding immunogold to detect expression of the glutamate transporters GLAST, GLT‐1, and EAAC1 in the mouse cochlear nucleus. Our results show that the glial transporters, GLAST and GLT‐1, are absent in synaptic nests. This deficiency is not compensated by the neuronal transporter EAAC1, which is poorly represented in nests. Outside synaptic nests, all three glutamate transporters are strongly expressed in the cochlear nucleus. Thus, glutamate released outside nests should be quickly bound by transporters and removed from the extracellular glutamate pool. Glutamate released within synaptic nests may persist long enough to permit diffusion to extrajunctional targets in the nest, including presynaptic receptors. Consequently, synaptic nests may play a role in modulation of synaptic activity but also in excitotoxic mechanisms. Synapse 49:29–46, 2003. © 2003 Wiley‐Liss, Inc.
Persistent and anatomically selective reduction in prefrontal cortical dopamine metabolism after repeated, intermittent cannabinoid administration to rats
Authors: Verrico Christopher D. , Jentsch J. David , Roth Robert H.
Published: April 2003

Long‐term abuse of delta‐9‐tetrahydrocannabinol (THC), the major psychoactive constituent of marijuana, produces behavioral and metabolic signs of frontal cortical dysfunction in humans; these effects persist even after short‐term abstinence. Based on a preliminary finding that repeated administration of THC to rats reduces basal frontal cortical dopamine turnover (Jentsch et al. [1998] Neurosci Lett 246:169–172), we further investigated the effects of repeated administrations of THC or WIN 55,212‐2 (WIN), a synthetic cannabinoid receptor agonist, on dopamine turnover in the prefrontal cortex, striatum, and nucleus accumbens. THC or WIN (twice daily for 7 or 14 days) caused a persistent and selective reduction in medial prefrontal cortical dopamine turnover; no significant alterations of dopamine metabolism were observed in the nucleus accumbens or striatum. Importantly, these dopaminergic deficits in the prefrontal cortex were observed after a drug‐free period of up to 14 days. Thus, the cognitive dysfunction produced by heavy, long‐term cannabis use may be subserved, in part, by drug‐induced alterations in frontal cortical dopamine turnover. Synapse 49:61–66, 2003. © 2003 Wiley‐Liss, Inc.
Sexuelle Belästigung am Telefon
Authors: Sczesny Sabine , Stahlberg Dagmar
Published: April 2003

Zusammenfassung: Sexuelle Belästigung am Telefon ist ein in der bisherigen sozialwissenschaftlichen Forschung vernachlässigtes Alltagsphänomen. Die vorliegende Studie zur Analyse dieses Phänomens wurde repräsentativ für Deutschland durchgeführt. In der ersten Phase der Studie wurde eine Ausgangsstich-probe von mehr als 3000 Personen mündlich mittels eines Fragebogens zu unerwünschten Ereignissen am Telefon im vorangegangenen Jahr befragt. Die Ergebnisse zeigen, welche verschiedenen Formen von Belästigung in welchem Umfang vorkommen (Stöhnanrufe, sexuelle Beleidigungen etc.). Dabei wurden die Häufigkeit sowie das Ausmaß der durch die sexuelle Belästigung hervorgerufenen Belastung analysiert. In der zweiten Phase wurde den Personen, die im vorangegangenen Jahr oder jemals in ihrem Leben ein Ereignis am Telefon als sexuell belästigend erlebt hatten, ein ausführlicher Fragebogen zu der von ihnen erlebten Belästigung zur schriftlichen Beantwortung vorgegeben. Schwerpunkt war dabei die Analyse des Verarbeitungsprozesses. Die Ergebnisse zeigen, welches (verbreitete) unmittelbare emotionale und kognitive Reaktionen auf sexuelle Belästigung am Telefon sind (Angst, Ärger etc.) und welche Copingstrategien angewandt werden (Vermeidung, positive Selbstinstruktion, Informationssuche, Suche nach sozialer Unterstützung etc.). Dabei wurde untersucht, inwieweit attributions-, kontroll- und streßtheoretische Ansätze Vorhersagen für die Bewältigung dieser Erfahrung ermöglichen.
Wir haben die Tour de France gewonnen!
Authors: Reinhard Marc-André , Jinschek Ralf , Diehl Michael
Published: April 2003

Zusammenfassung: In zwei Experimenten wurde überprüft, ob eine erhöhte relative Verfügbarkeit des Erfolges von Jan Ullrich bei der Tour de France 1997 bei Deutschen zu einer stärkeren Identifikation mit ihrer Nation führt. In Experiment 1 wurde die relative Verfügbarkeit des Erfolges von Jan Ullrich direkt mit Hilfe eines Fragebogens manipuliert, in Experiment 2 indirekt, und zwar durch die erhöhte Verfügbarkeit des gelben Trikots, dem Symbol seines Erfolgs. In beiden Experimenten zeigte sich, daß Personen, bei denen der Erfolg im Vergleich zu einer Kontrollgruppe verfügbarer gemacht wurde, eine höhere Identifikation mit der Nation berichteten.
«Stechen statt Sprechen»: Valenz und Aktivierbarkeit von Stereotypen über Türken
Authors: Kahraman B. , Knoblich G.
Published: April 2003

Zusammenfassung: In zwei Untersuchungen gingen wir der Frage nach, was die Inhalte stereotypen Wissens über in Deutschland lebende Türken und Deutsche sind, und ob diese Stereotype automatisch aktiviert werden. In der ersten Untersuchung befragten wir deutsche ProbandInnen (n = 20) über ihr Wissen zu kulturellen Stereotypen über Türken und Deutsche. Die ProbandInnen generierten zwar gleich viele negative Aussagen über das deutsche und türkische Stereotyp, aber deutlich weniger positive Aussagen über das türkische Stereotyp. In der zweiten Untersuchung überprüften wir die automatische Aktivierbarkeit der Kategorien «türkisch» und «deutsch» in einer Priming-Anordnung. ProbandInnen (n = 18) beurteilten türkische und deutsche Vornamen, nachdem zuvor ein mit dem jeweiligen Stereotyp konsistenter oder inkonsistenter Prime vorgegeben worden war. Die Vorgabe konsistenter Primes führte zu einer Beschleunigung der Reaktionszeiten. Die Ergebnisse unterstützen die Hypothese, daß die sozialen Kategorien «Türkisch» und «Deutsch» durch assoziierte Attribute automatisch aktiviert werden.
Beurteilung einzelner Stimuli des Ausdrucksverhaltens ohne ihre entsprechenden Kontext- und Begleitmerkmale
Authors: Kempter Guido , Möller Carsten
Published: April 2003

Zusammenfassung: Die Untersuchung galt der Frage, welche Bedeutung ausschließlich den Körper- und Gliederbewegungen des Menschen in face-to-face Situationen bei der Eigenschaftsattribution zukommt. Hierzu wurde das Verfahren der Skriptanimation eingesetzt, womit sich die entsprechenden Bewegungen von anderen normalerweise zur Verfügung stehenden Informationen isolieren und auf eine Computerpuppe übertragen lässt. Insgesamt 153 Versuchspersonen nahmen an drei Versuchsreihen teil und beurteilten nacheinander 12 verschiedene Fernsehakteure: 55 Vpn beurteilten die Originalaufzeichnung der Akteure; 33 Vpn beurteilten die originalgetreu reanimierten Körper- und Gliederbewegungen der Darsteller; 65 Vpn beurteilten die im Bewegungsablauf modifizierten Animationen. Als Beurteilungsinstrument wurden Ratingskalen eingesetzt. Die Ergebnisse veranschaulichen, dass die Eliminierung bzw. Konstanthaltung aller Begleit- und Kontextinformationen keinen systematischen Einfluss auf die Eigenschaftsattributionen ausübte. Andererseits genügten bereits kleine Modifikationen im Bewegungsablauf der Kopf- und Rumpfbewegungen, damit sich das Bild, das sich die Vpn von den dargestellten Personen machten, auf nahezu allen Urteilsskalen entweder verbesserte oder verschlechterte. Die Ergebnisse werden mit Erkenntnissen aus Multikanalanalysen nonverbalen Verhaltens in Zusammenhang gebracht.
Honesty, Trust and Economic Growth
Authors: Fetchenhauer Detlef , van der Vegt Gerben
Published: April 2003

Summary: This article investigates cross-country differences in economic growth rates from a psychological perspective. Based on social capital theory it is argued that 1) financial honesty and trust are positively correlated with each other when they are aggregated on a country level and that 2) a high level of financial honesty and trust in a given country reduces transaction costs and thus stimulates economic growth. Using data from the World-Value-Surveys in 1981 and 1990 these hypotheses are empirically confirmed. The influence of social capital (i.e., financial honesty and trust) on economic growth was robust and substantial even if a number of relevant variables like gross national product (GNP), urbanization, economic inequality or the proportion of agriculture in gross domestic product were controlled. Thus, it seems worthwhile for economic psychology to further explore the influence of psychological determinants (like trust and honesty) on macroeconomic variables like economic growth or wealth.
Zur kognitiven Konstruktion von (Un-)Gerechtigkeit militärischer Gewalt
Authors: Cohrs J. Christopher , Moschner Barbara
Published: April 2003

Zusammenfassung: Am Beispiel der moralischen Beurteilung des Kosovo-Kriegs wurde untersucht, über welche Mechanismen die (Un-)Gerechtigkeit militärischer Gewalt kognitiv konstruiert wird. Es wurde argumentiert, dass vier Formen der Re-Interpretation des Ereignisses - Negierung negativer Folgen der Militäraktion, Ablehnung der Verantwortung des Westens für den Krieg, Beschuldigung Jugoslawiens und Rechtfertigung der Intervention durch positive Motive - mit einer positiven Bewertung des Militäreinsatzes der NATO einhergehen. Als Determinanten der Beurteilung des Kriegs wurden der Glaube an eine gerechte Welt, Militarismus-Pazifismus, Autoritarismus und Systemunterstützung berücksichtigt. Die Hypothesen wurden mit Hilfe von Strukturgleichungsmodellen an 165 Studierenden überprüft. Die vier Formen der Re-Interpretation hingen stark mit der Bewertung des Militäreinsatzes zusammen, sodass ihre Relevanz in Bezug auf militärische Gewalt gezeigt wurde. Weiterhin zeigte sich hypothesenkonform ein starker Einfluss der erhobenen politischen Einstellungen auf die Beurteilung des Kriegs, jedoch hypothesenkonträr kein Einfluss des Gerechte-Welt-Glaubens. Die kausale Bedeutung der Re-Interpretationen und das Zusammenspiel zwischen Gerechte-Welt-Glaube und politischen Einstellungen werden diskutiert.
Helfen Implementationsintentionen, die Lücke zwischen Absicht und Verhalten zu überwinden?
Authors: Bamberg Sebastian
Published: April 2003

Zusammenfassung: Im Kontext von zwei Feldexperimenten werden die Implikationen des von Gollwitzer entwickelten Konzepts der Implementationsintention für Ajzens Theorie des geplanten Verhaltens untersucht. Es wird die Zielintention gemessen, innerhalb einer Woche eine neue Verhaltensweise (Test einer Buslinie bzw. Kauf in einem Bioladen) auszuführen. Die Experimentalgruppen werden dann mittels eines Fragebogenzusatzes dazu angeregt, eine zusätzliche Implementationsintention zu bilden, d.h. genau zu planen, wann, wo und wie sie die neuen Verhaltensweisen ausführen wollen. In beiden Studien führt die Bildung einer Implementationsintention dazu, dass die beabsichtigte neue Verhaltensweise häufiger ausgeführt wird. Ferner scheint die Bildung einer Implementationsintention den Einfluss konkurrierender Verhaltensgewohnheiten zu unterdrücken. In der zweiten Studie wird die Wirkung der Implementationsintention mit der Wirkung eines finanziellen Anreizes verglichen. Die Befunde deuten darauf hin, dass finanzielle Anreize ebenfalls die Bildung einer Implementationsintention stimulieren.
Skalen zur Erfassung von Bindungsrepräsentationen in Paarbeziehungen
Authors: Grau Ina
Published: April 2003

Zusammenfassung: Die Bindungstheorie stellt zur Zeit einen der einflußreichsten Ansätze in der Partnerschaftsforschung dar. Um individuelle Unterschiede in den Bindungsrepräsentationen zu erfassen, liegen einige Meßinstrumente aus dem amerikanischen Sprachraum vor. Aus diesen Quellen wurde ein Fragebogen erstellt, der einige Probleme vermeidet, insbesondere was niedrige Reliabilität und das gleichzeitige Ansprechen verschiedener Bindungspersonen innerhalb einer Skala angeht. Es wurden zwei intern konsistente, voneinander unabhängige Skalen aus je 10 Items erstellt, die Angst und Vermeidung als zwei Dimensionen der Bindungsunsicherheit erfassen. Eine sichere Bindung ergibt sich aus einer niedrigen Ausprägung in beiden Skalen. Die Skalen hängen mit der Beziehungsqualität zusammen.
Überprüfung des Youth Self-Report an einer nichtklinischen Stichprobe
Authors: Roth Marcus
Published: April 2003

Zusammenfassung: Die deutschsprachige Version des Youth Self-Report (YSR) wurde einer nichtklinischen Stichprobe vom 352 Jugendlichen im Alter zwischen 12 und 16 Jahren vorgegeben und im Hinblick auf Reliabilität (interne Konsistenz), Skaleninterkorrelationen und Anwendbarkeit der amerikanischen Normierung überprüft. Die Ergebnisse zeigen, daß die Skalen «Sozialer Rückzug», «Körperliche Beschwerden», «Soziale Probleme», «Schizoid/zwanghaft» und «Aufmerksamkeitsstörungen» nur ungenügende und für die Individualdiagnostik unbefriedigende interne Konsistenzen (α < .70) aufweisen. Weiterhin zeigen die Ergebnisse, daß im Vergleich zur amerikanischen Normierungsstichprobe ca. zwei- bis dreimal so viele Jugendliche dieser Studie in den oberen Wertebereich des YSR fallen. Die Interpretation individueller Werte anhand amerikanischer Normen führt daher zu einer deutlichen Überschätzung der psychischen Symptombelastung und sollte somit in der Individualdiagnostik keine Anwendung finden.
Interaktionseffekte Monoamin-relevanter genetischer Polymorphismen mit Traits des TPQ
Authors: Strobel Alexander , Brocke Burkhard , Ebstein Richard P.
Published: April 2003

Zusammenfassung: Fortschritte in der Molekulargenetik ermöglichen es, den Erklärungsbeitrag genetischer Polymorphismen mit funktioneller Relevanz zum genetischen Hintergrund der Erblichkeitskomponente einiger Persönlichkeitstraits zu untersuchen. Bisherige Befunde sprechen für potentielle Assoziationen eines Polymorphismus im Dopamin-D4-Rezeptor-Gen (DRD4 Exon 3) mit der Dimension Novelty Seeking (NS) des Tridimensional Personality Questionnaire (TPQ) sowie eines Polymorphismus des Serotonin-Transporter-Gens (5-HTTLPR) mit TPQ Harm Avoidance (HA). Die Betrachtung von Interaktionen dieser Polymorphismen kann einen Beitrag zur Klärung von Inkonsistenzen in bisherigen Assoziationsstudien leisten. In der vorliegenden Arbeit wurden für 134 Personen Interaktionen von DRD4 Exon 3 und 5-HTTLPR sowie einem Polymorphismus des Gens für COMT auf die Faktorwerte der TPQ-Subskalen überprüft. Es zeigten sich Tendenzen zu Interaktionen zwischen DRD4 Exon 3 und 5-HTTLPR bei dem HA-Faktor sowie zwischen DRD4 Exon 3 und dem COMT-Polymorphismus bei dem NS-Faktor.
Dopaminerge Mechanismen und Extraversion
Authors: Rammsayer Thomas
Published: April 2003

Zusammenfassung: Der vorliegende Beitrag greift die Frage auf, inwieweit Eysencks «Arousal-Theorie der Extraversion» angesichts zahlreicher neuerer Forschungsergebnisse aus dem Bereich der Neurowissenschaften und der biologischen Persönlichkeitsforschung modifiziert werden müßte. Insbesondere Ergebnisse der tierexperimentellen und humanwissenschaftlichen Grundlagenforschung der letzten zehn Jahre haben vermehrt Anhaltspunkte geliefert, daß dem Neurotransmitter Dopamin eine zentrale Rolle als biologisches Substrat der Extraversion zuzukommen scheint. In einer Reihe von eigenen Untersuchungen konnte belegt werden, daß sich Introvertierte und Extravertierte nicht in ihrem absoluten Niveau zentralnervöser Aktivität unterscheiden. Vielmehr bestehen Unterschiede in der behavioralen Sensitivität, mit der Intro- und Extravertierte auf Abweichungen vom physiologischen Niveau der dopaminergen Aktivierung reagieren. Introvertierte scheinen sich dabei durch eine deutlich höhere Responsivität im Vergleich zu Extravertierten auszuzeichnen, da sie pharmakologisch oder durch natürliche Lebensereignisse verursachte Abweichungen vom habituellen Niveau dopaminerger Aktivierung vermutlich in sehr viel größerem Maße zu tolerieren scheinen. Abschließend werden grundlegende konzeptuelle Fragen für zukünftige Untersuchungen aufgeworfen.
Aktuelle Aktiviertheit und selektive Aufmerksamkeit: Ein Beitrag zur Hypothese von der umgekehrt u-förmigen Beziehung zwischen Aspekten der Aktiviertheit und Leistungsmerkmalen
Authors: Imhof Margarete
Published: April 2003

Zusammenfassung: Die Studie dient der Überprüfung einer Facette der Hypothese von der umgekehrt u-förmigen Beziehung zwischen Aktiviertheit und Leistung. Dabei wird von den folgenden Prämissen ausgegangen: 1) Veränderungen im Niveau der aktuellen Aktiviertheit wirken sich besonders deutlich auf selektive Aufmerksamkeitsleistungen aus; und 2) zur angemessenen Interpretation der Ergebnisse ist es erforderlich, das Niveau der aktuellen Aktiviertheit zu quantifizieren. In einer Untersuchung an N = 380 Studierenden wurde zuerst das Niveau der aktuellen Aktiviertheit erhoben und danach eine Selektionsaufgabe gestellt (Test d2: Aufmerksamkeits- Belastungs-Test nach Brickenkamp). Die Ergebnisse zeigen den erwarteten Zusammenhang: Sehr niedrig und sehr hoch aktivierte Probanden schneiden in den Leistungskriterien des Tests d2 schlechter ab als gemäßigt aktivierte Probanden. Dieser Effekt tritt in der Anfangsphase (entspricht den ersten drei Zeilen) der Testdurchführung besonders deutlich auf. Die Frage bleibt, ob die (Selbst-)Regulation von Aktiviertheit strategisch zur Optimierung von Aufgabenorientierung eingesetzt werden kann.
Selbstaufmerksamkeit und “Selbst-Kenntnis” im SAM-Fragebogen
Authors: Hoyer Jürgen , Kunst Heike
Published: April 2003

Zusammenfassung: Trotz verschiedentlicher Hinweise auf die fragliche Homogenität von Skalen zur Erfassung “privater Selbstaufmerksamkeit” fehlen diesbezügliche faktorenanalytische Untersuchungen im deutschen Sprachraum. Wir haben deshalb die Skala “private Selbstaufmerksamkeit” aus dem “Fragebogen zur Erfassung der dispositionellen Selbstaufmerksamkeit” (SAM-Fragebogen) von Filipp & Freudenberg (1989) an drei Stichproben von N = 222 Gesunden, N = 91 Reha-Patienten und N = 165 Alkoholpatienten mittels Hauptkomponentenanalyse und konfirmatorischer Faktorenanalyse (LISREL) auf ihre Homogenität geprüft. Übereinstimmend zeigt sich neben einem Faktor “Selbstaufmerksamkeit” ein weiterer Faktor “Selbst-Kenntnis”, der inhaltlich gut im Sinne selbstzugeschriebener Selbsterkenntnis zu interpretieren ist. Auf der Basis der beiden Faktoren gebildete Subskalen korrelieren in unseren Studien teilweise gegenläufig mit verschiedenen psychologischen Maßen (z.B. der Symptombelastung). Dies erklärt unbefriedigende Ergebnisse in aktuellen Studien und spricht für eine Revision des Fragebogens.