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  • Electronic Resource  (4,887)
  • 1995-1999  (4,887)
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  • Electronic Resource  (4,887)
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  • 1995-1999  (4,887)
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  • 101
    Electronic Resource
    Electronic Resource
    Dissociation between cognitive and motor/motivational deficits in the delayed matching to position test: effects of scopolamine, 8-OH-DPAT and EAA antagonists (1995)
    Springer
    Psychopharmacology 122 (1995), S. 268-280 
    Details
    ISSN: 1432-2072
    Keywords: Operant delayed matching task ; MK-801 ; CGS 19755 ; Scopolamine ; 8-OH-DPAT ; Cognition ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of the muscarinic antagonists scopolamine HBr and MeBr, the 5-HT1A agonst 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), and theN-methyl-d-aspartate (NMDA) antagonists MK-801 and CGS-19755 on performance of rats in a delayed matching-to-position task were examined. Pretreatment with scopolamine HBr (0.05 and 0.1 mg/kg), resulted in a delay-dependent decrease in the percentage of correct responses and discriminability (logd), but had no effect on either the latency to complete trials, or the rate of trial completion during the fixed duration session. Scopolamine MeBr (0.1 mg/kg) did not impair percent correct or increase the response latency but did decrease the rate of trial completion. 8-OH-DPAT (up to 0.3 mg/kg), had no effect on percent correct, but did induce a small decrease in discriminability. The impairment in discriminability occurred only at a dose that substantially reduced the rate of trial completion. Both MK-801 (0.05 mg/kg) and CGS 19755 (10 mg/kg) induced a delay-independent impairment in percent correct, discriminability and a reduction in the rate of trial completion without affecting latency. A lower dose of CGS 19755 (5.0 mg/kg) induced a slight impairment in discriminability without significantly affecting the other measures. Taken together, these results demonstrate some dissocation between drug-induced cognitive and motor/motivational deficits in the DMTP test. However, the data question the specificity of putative cognitive impairments reported in many previous studies with the 5-HT1A agonist 8-OH-DPAT.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02246548
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  • 102
    Electronic Resource
    Electronic Resource
    Effects of morphine on different aspects of social play in juvenile rats (1995)
    Springer
    Psychopharmacology 117 (1995), S. 225-231 
    Details
    ISSN: 1432-2072
    Keywords: Social play ; Opioid ; Morphine Environment ; Social isolation ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To clarify the influence of opioids on social play, the effects of morphine on playful and non-playful social behavior in juvenile rats was investigated under different conditions. Environmental variables employed were different (dim and intense) levels of illumination during testing, familiarity to the test cage, and different periods of social isolation prior to testing. Under dim light conditions, morphine markedly increased playful social behavior, such as pinning, boxing/wrestling and following/chasing, whereas non-playful social behavior such as social exploration and contact behavior was hardly affected. This effect of morphine was independent of duration of previous isolation and dose-dependent, with a maximal effect at 1.0 mg/kg. The mechanism of this effect is interpreted as an action on the rewarding aspects of play. A dose of 0.1 mg/kg of morphine abolished the initial suppression of play induced by unfamiliarity to the test cage, without influencing total levels of play. This may be an effect of morphine on the integration of sensory stimuli. Under intense light conditions, where playful behavior was completely suppressed, morphine itself hardly affected such behavior, but decreased some aspects of non-playful social behavior. These results suggest that in juvenile rats playful and non-playful forms of social behavior are differentially regulated. In addition, opioid systems may be involved at different levels in the regulation of social play.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02245191
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  • 103
    Electronic Resource
    Electronic Resource
    The role of the ascending 5-hydroxytryptaminergic pathways in timing behaviour: further observations with the interval bisection task (1995)
    Springer
    Psychopharmacology 120 (1995), S. 213-219 
    Details
    ISSN: 1432-2072
    Keywords: 5-hydroxytryptamine ; 5,7-Dihydroxytryptamine ; Operant behaviour ; Timing ; Interval bisection procedure ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This experiment examined the effect of destroying the 5-hydroxytryptaminergic (5HTergic) pathways on rats' ability to discriminate between two durations. Rats received injections of 5,7-dihydroxytryptamine into the median and dorsal raphe nuclei or sham lesions. They were trained to press lever A following a 2-s presentation of a light and lever B following an 8-s presentation of the light. For some rats, the levers were inserted into the chamber immediately after stimulus presentation (“no-poke-requirement”); for others, the levers were not inserted until a flap covering the food tray positioned midway between the levers had been depressed (“poke-requirement”). When stable performance was attained, “probe” trials were introduced in which the light was presented for intermediate durations. Logistic functions were derived relating percent choice of lever B to log stimulus duration. Under the “no-poke-requirement” condition, the bisection point (duration yielding 50% choice of lever B) was shorter in the lesioned rats than in the control rats. Under the “poke-requirement” condition, this effect of the lesion was attenuated. There was no effect of the lesion on the Weber fraction under either condition. The levels of 5HT and 5-hydroxyindoleacetic acid were reduced in the brains of the lesioned rats, but the levels of noradrenaline and dopamine were not altered. It is proposed that rats may attain accurate timing under the interval bisection task by moving from one lever to the other during stimulus presentation; this movement may be facilitated by destruction of the 5HTergic pathways. Accurate timing is still possible when this movement is suppressed by the introduction of a “poke requirement”; however, in this case timing is not affected by 5HT depletion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02246196
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  • 104
    Electronic Resource
    Electronic Resource
    Acute and subchronic effects of clozapine on licking in rats: tolerance to disruptive effects on number of licks, but no tolerance to rhythm slowing (1995)
    Springer
    Psychopharmacology 120 (1995), S. 249-255 
    Details
    ISSN: 1432-2072
    Keywords: Clozapine ; Ritanserin ; Atypical neuroleptic ; Lick rhythm ; Oscillator slowing ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In order to assess the effects of the atypical neuroleptic clozapine on orolingual competence in rats, tongue function was measured by quantitating the rhythm of tongue movements after acute (1.0, 3.0, 6.0 mg/kg) or subchronic intraperitoneal treatment (1.5, 3.0, 4.5 mg/kg, each dose for at least 7 days) with the drug. Thirsty rats were trained to lick water from a force-sensing disk by thrusting the tongue through a 12-mm-diameter hole to strike the horizontal disk located 5 mm below the hole. Number of licks in 2 min and rhythm of tongue movements (as determined by Fourier analysis of the force-time signal) were each dose dependently reduced in the acute dose-effect phase of the study. In the subchronic study number of licks exhibited tolerance, but the slowing of lick rhythm did not show tolerance. An acute dose range of the serotonin antagonist ritanserin (0.5, 1.0, 2.0, 4.0 mg/kg) was also studied in the same rats. Ritanserin had no effect on any of the measures of orolingual function. The clozapine result was replicated in a second study using younger, drug naive rats. The results for clozapine were contrasted with previous reports indicating that haloperidol has little effect on lick rhythm. Additional discussion evaluated the possible contribution of neurotransmitter receptors on motor neurons of the hypoglossal nucleus to the observed rhythm slowing induced by clozapine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02311171
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  • 105
    Electronic Resource
    Electronic Resource
    Amphetamine analogs have differential effects on DRL 36-s schedule performance (1995)
    Springer
    Psychopharmacology 121 (1995), S. 57-65 
    Details
    ISSN: 1432-2072
    Keywords: Operant behavior ; Amphetamine ; Methamphetamine ; Methylenedioxymethamphetamine ; Fenfluramine ; Parachloroamphetamine ; Dopamine ; Serotonin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Amphetamine and related compounds have previously been shown to differentially release dopamine (DA) and serotonin (5HT) in vivo and in vitro. The purpose of this report is directly to compare five amphetamine analogs on differential reinforcement of low rate 36-s (DRL 36-s) schedule performance, and to determine whether the reported increases in dopamine and/or serotonin release induced by these drugs can be related to observed behavioral differences. Amphetamine (AMPH) and methamphetamine (METH) induced large increases in response rate, methylene-dioxymethamphetamine (MDMA) and para-chloroamphetamine (PCA) caused small increases in response rate, while fenfluramine (FEN) had no effect on response rate. AMPH, METH, PCA and MDMA caused a dose-dependent decrease in reinforcement rate, and FEN had no effect on reinforcement rate. AMPH, METH, and PCA but not FEN, shifted the peak of the inter-response time (IRT) distribution toward shorter intervals, MDMA decreased peak location only at the highest dose. All five drugs caused a dose-dependent decrease in peak area, indicating a loss of schedule control on the DRL 36-s schedule. Consistent with in vitro and in vivo release studies, the differential results of these five drugs on DRL 36-s schedule performance suggest a predominant dopamine role for AMPH and METH, a predominant serotonin role for FEN, and different degrees of combined dopaminergic and serotonergic roles for MDMA and PCA in the mediation of the task.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02245591
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  • 106
    Electronic Resource
    Electronic Resource
    Effects of benzodiazepine receptor partial inverse agonists in the elevated plus maze test of anxiety in the rat (1995)
    Springer
    Psychopharmacology 121 (1995), S. 118-126 
    Details
    ISSN: 1432-2072
    Keywords: Anxiety ; Plus maze ; Rat ; Benzodiazepine receptor ; DMCM ; FG 7142 ; Yohimbine ; Pentylenetetrazol ; β-Carboline ; Inverse agonist
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The present series of experiments examined the effects of five benzodiazepine receptor (BZR) partial inverse agonists on the behaviour of rats on an elevated plus maze. The drugs were tested in a standard plus maze with 3-cm walls added to the open arms, as this has been shown to increase the sensitivity of the plus maze to anxiogenic-like drug effects (Jones and Cole 1995). The drugs tested were FG 7142 (0–100 mg/kg),β-CCE (0–30 mg/kg), ZK 132 556 (0–100 mg/kg), ZK 90 886 (0–30 mg/kg) and Ro 15–4513 (0–30 mg/kg). In addition, to allow a comparison with previous studies, the effects of three reference substances, DMCM (0–2.5 mg/kg), pentylenetetrazol (PTZ; 0–30 mg/kg) and yohimbine (0–5 mg/kg), were also examined. These three reference compounds produced a dose-dependent reduction in the duration of open arm exploration and the total number of open arm entries, indicative of anxiogenic-like effects. DMCM produced significant effects at the doses of 1.25 and 2.5 mg/kg, PTZ at 30 mg/kg, and yohimbine at 5 mg/kg. The BZR partial inverse agonist FG 7142 (10, 30 and 100 mg/kg) also reduced the duration of open arm exploration and the total number of arm entries. The minimally effective dose resulted in a receptor occupancy of approximately 80%. Ro 15–4513 also produced anxiogenic-like effects, but only at a dose (30 mg/kg) that resulted in a receptor occupancy of approximately 95%. In contrast, the other BZR partial inverse agonists, ZK 132 553 and ZK 90 886, did not significantly reduce the duration of open arm exploration, even at doses that produced greater than 95% receptor occupancies.β-CCE also did not reduce open arm exploration at any dose tested (0–30 mg/kg). The GABA shift, a biochemical index of intrinsic activity, indicates that these latter three compounds are more inverse agonistic than Ro 15–4513. In summary, these results demonstrate that not all BZR receptor partial inverse agonists have anxiogenic-like activity in the rat plus maze, and that the GABA shift, a biochemical index of intrinsic efficacy, does not predict which BZR partial inverse agonists are anxiogenic.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02245598
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  • 107
    Electronic Resource
    Electronic Resource
    Failure of CCK receptor ligands to modify anxiety-related behavioural suppression in an operant conflict paradigm in rats (1995)
    Springer
    Psychopharmacology 121 (1995), S. 127-134 
    Details
    ISSN: 1432-2072
    Keywords: Anxiety ; Cholecystokinin ; CCK-A and CCK-B receptor antagonists ; CCK-B receptor agonists ; Behavioural suppression ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of cholecystokinin (CCK) receptor ligands were studied in the rat safety signal withdrawal conflict procedure, an operant paradigm sensitive to both anxiolytic and anxiogenic compounds. In this procedure, behavioural suppression of lever pressing for food was induced by the withdrawal of a conditioned signal for safety without the usual presentation of a conditioned signal for danger. The compounds tested were selective CCK-B antagonists [CI-988 (0.01–1 mg/kg SC), L-365,260 (0.004–2 mg/kg IP) and LY 262,691 (0.001–1 mg/kg SC)], CCK-B agonists [CCK-4 (0.01–1 mg/kg SC) and BC 264 (0.004–1 mg/kg IP)] and CCK-A antagonists [devazepide (0.001–1 mg/kg SC) and lorglumide (0.01–1 mg/kg SC)]. None of these drugs induced the expected behavioural effects, i.e. an anxiolytic-like release of the behavioural suppression with CCK-B and, possibly, CCK-A antagonists and/or a further reduction of lever pressing with CCK-B agonists, indicative of an anxiogenic-like potential. In contrast, the established anxiolytic lorazepam (0.06–0.25 mg/kg IP), as well as diazepam (2 mg/kg IP) and buspirone (0.25 mg/kg SC) used as positive control drugs, released the suppression of pressing for food during the period associated with the safety signal withdrawal, whereas picrotoxin (1 mg/kg IP), used as an anxiogenic control, further reduced responding during this conflict period. The present results contrast with a series of published data suggesting the involvement of CCK processes in anxiety-related behaviour in rodent models such as the elevated plus-maze or the light:dark two compartment test, and in panic disorders in humans. They indicate that the behavioural effects of one category of drugs might vary considerably, depending on the experimental situation. Furthermore, they allow the conclusion that anticipatory anxiety generated by withdrawal of conditioned signals for safety does not involve CCK-related processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02245599
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  • 108
    Electronic Resource
    Electronic Resource
    Diazepam prevents progression of kindled alcohol withdrawal behaviour (1995)
    Springer
    Psychopharmacology 121 (1995), S. 451-460 
    Details
    ISSN: 1432-2072
    Keywords: Alcohol withdrawal ; Diazepam ; Kindling ; Seizures ; Rat ; Paradigm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The purpose of the present experiment was to study the “kindling” hypothesis of alcohol withdrawal stating that exposure to repeated episodes of alcohol withdrawal results in an increased severity of subsequent withdrawal reactions. Two groups of male Wistar rats were subjected to 13 episodes of 2 days severe alcohol intoxication and 5 days alcohol withdrawal. Animals in the control group (n=80) developed clinical withdrawal signs following each intoxication episode. In the diazepam group (n=80) the withdrawal reactions during episodes 1–9 were blocked by intraperitoneal diazepam administration (0–30 mg/kg) 8, 11 and 15 h into withdrawal. During episode 10–13 diazepam treatment was terminated and convulsive withdrawal behaviour was observed 9–15 h after last alcohol dose. The probability of seizure activity during these four withdrawal episodes was calculated as 0.239 and 0.066 in the control and the diazepam groups, respectively. Based on Monte Carlo simulation techniques, this difference was found to be statistically significant (P〈0.05). No differences in the non-convulsive alcohol withdrawal symptoms tremor, hyperactivity and rigidity were detected between controls and diazepam animals after diazepam treatment. It was concluded that the increased convulsive behaviour in the control group was caused by cumulated kindling-like cerebral alterations during the previous repeated alcohol withdrawal phases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02246493
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  • 109
    Electronic Resource
    Electronic Resource
    Social deprivation enhances the vulnerability of male Wistar rats to stressor- and amphetamine-induced behavioral sensitization (1995)
    Springer
    Psychopharmacology 117 (1995), S. 116-124 
    Details
    ISSN: 1432-2072
    Keywords: Psychostimulant ; Amphetamine ; Stress ; Long-term sensitization ; Social isolation ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The aim of the present study was to assess the influence of experimential factors on the vulnerability of rats to develop amphetamine (AMPH)- and stressor-induced behavioral sensitization. Young male Wistar rats with previous social experience were isolated from their peers for 2 weeks. 1) The effect of this short-lasting social deprivation were: a) a reduced tendency to explore a fearful environment; b) a prolonged exploratory activity in response to a novel but little fearful environment; and c) a dose-dependent increase in the psychomotor stimulation induced by systemic AMPH injection. 2) After repeated AMPH injections (injection every other day for 10 days), isolated rats exhibited behavioral sensitization at lower doses (0.5 and 0.75 mg/kg) than those required for group-housed rats (1 mg/kg). 3) After being submitted to a repeated stressor (3, 7 or 14 footshock sessions, with 2 days between sessions), the isolated rats exhibited a greater increase in the behavioral responsivity to a subsequent AMPH challenge (1 mg/kg) than did the group-housed rats regardless of the number of stress sessions. In conclusion, these results suggest that experiential factors such as privation of contact with peers (social isolation) may make rats more vulnerable to the long-term repercussions of chronic environmental and pharmacological challenges.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02245106
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  • 110
    Electronic Resource
    Electronic Resource
    Intravenous morphine self-administration by rats with low versus high saccharin preferences (1995)
    Springer
    Psychopharmacology 117 (1995), S. 248-252 
    Details
    ISSN: 1432-2072
    Keywords: Morphine ; Self-administration Saccharin ; Taste ; Opioid ; Reward ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract An experiment was performed to determine the relationship between saccharin preference and the self-administration of morphine via the oral and intravenous routes. On the basis of voluntary intake of a saccharin solution by male rats, low and high preference groups were formed. Rats selected for high saccharin preference self-administered more morphine intravenously than rats selected for low preference. The two groups did not differ in oral morphine intake. The positive relationship between the intake of saccharin and intravenous morphine self-administration may be due to their mediation by a common mechanism. Measures of taste sensitivity or preference may be useful in identifying individuals at risk for drug abuse.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02245194
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  • 111
    Electronic Resource
    Electronic Resource
    The differential behavioural effects of benzazepine D1 dopamine agonists with varying efficacies, co-administered with quinpirole in primate and rodent models of Parkinson's disease (1995)
    Springer
    Psychopharmacology 117 (1995), S. 287-297 
    Details
    ISSN: 1432-2072
    Keywords: D1 dopamine agonists ; Quinpirole ; MPTP Marmoset ; Rat ; 6-Hydroxydopamine ; Behaviour
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of co-administration of quinpirole with benzazepine D1 dopamine (DA) agonists possessing full/supramaximal (SKF 80723 and SKF 82958), partial (SKF 38393 and SKF 75670) and no efficacies (SKF 83959) in stimulating adenylate cyclase (AC) were investigated in rodent and primate models of Parkinson's disease (PD). In rats with a unilateral 6-hydroxydopamine (6-OHDA) lesion of the medial forebrain bundle, co-administration of SKF 38393 (7,8-dihydroxy-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine), SKF 75670 (3-CH3 analogue), SKF 80723 (6-Br analogue), SKF 83959 (6-Cl, 3-CH3, 3′-CH3 analogue) and SKF 82958 (6-Cl, 3-C3H5 analogue) strongly potentiated the contralateral circling induced by quinpirole. In MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) treated common marmosets, administration of quinpirole alone increased locomotor activity and reversed motor deficits. Grooming and oral activity were unaltered. Co-administration of SKF 38393 and SKF 75670 inhibited the quinpirole-induced changes in locomotor activity and motor disability. The combined treatment of SKF 80723 or SKF 82958 with quinpirole had no overall effect on locomotor activity or motor disability. In contrast, SKF 83959 extended the duration of the quinpirole-induced increase in locomotor activity with corresponding decreases in motor disability. Co-administration of high doses of SKF 82958 and more especially SKF 83959 and SKF 80723, with quinpirole induced hyperexcitability and seizures. Oral activity and grooming were unaltered following the co-administration of benzazepine derivatives with quinpirole. The ability of some benzazepine D1 DA agonists to prolong the antiparkinsonian effects of quinpirole in the MPTP-treated marmoset may indicate a role for certain D1 DA agonists in the clinical treatment of PD. In general, the behavioural responses to the combined administration of benzazepines with quinpirole in the 6-OHDA lesioned rat and more especially the MPTP-treated marmoset failed to correlate with their ability to stimulate AC. These observations further implicate a behavioural role for D1 DA receptors not linked to AC.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02246103
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  • 112
    Electronic Resource
    Electronic Resource
    Effect ofd-fenfluramine on the indole contents of the rat brain after treatment with different inducers of cytochrome P450 isoenzymes (1995)
    Springer
    Psychopharmacology 118 (1995), S. 188-194 
    Details
    ISSN: 1432-2072
    Keywords: d-Fenfluramine ; Brain kinetics ; Indole-depleting effect ; Inducers of drug metabolism ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of pretreatment with inducers of hepatic cytochrome P450 isoenzymes (phenobarbital, dexamethasone andβ-naphthoflavone) on the metabolism ofd-fenfluramine (d-F) and its acute and long-lasting indole-depleting effects were studied in rats, in an effort to obtain further information on the importance of hepatic drug metabolism in relation to its neurochemical actions. Twenty-four hours after the last dose of each inducer, rats were injected withd-F hydrochloride (5 mg/kg, IP) and killed at various times thereafter for parallel determination of indoles and drug concentrations in plasma and brain. Additional rats were treated as above and killed 1 week afterd-F hydrochloride (5 and 10 mg/kg) to study the recovery of indole in the cortex, a particularly sensitive brain area. Phenobarbital andβ-naphthoflavone and, to a lesser degree, dexamethasone, stimulated the metabolism ofd-F, as evidenced by a decrease in plasma and brain areas under the curve (AUC) compared to vehicle-treated rats. This indicated that multiple isoenzymes are capable of mediating the drug's metabolism, primarily byN-dealkylation tod-norfenfluramine (d-NF). None of the inducers raised plasma and brain AUC of the nor-derivative, and in fact phenobarbital and particularlyβ-naphthoflavone reduced it. These different effects were even apparent in rats givend-NF (2.5 mg/kg), indicating that both phenobarbital andβ-naphthoflavone also stimulate the sequential metabolism of the nor-metabolite (byN-deamintaion) which, however, is apparently enhanced most actively byβ-naphthoflavone-inducible forms of P-450. Total “active” brain concentrations (d-F+d-NF) after the different pretreatments were in the order ofβ-naphthoflavone 〈 phenobarbital 〈 dexamethasone ≤ vehicle. Interestingly,β-naphthoflavone rapidly reversed the depletion of brain indoles caused byd-F (andd-NF); phenobarbital provided partial protection and dexamethasone did not appreciably modify either the acute or long-term neurochemical effects of the drug. The fact that phenobarbital affectedd-NF kinetics less thanβ-naphthoflavone, and provided only partial protection against the acute and long-lasting neurochemical effects of high doses ofd-F, further stresses the critical role ofd-NF in the neurochemical outcome of its parent drug. These findings support the view that the degree and duration of the indole-depleting effects are related to critical brain concentrations of the parent compound and its nor-derivative, and provide indirect evidence that hepatic metabolites other thand-NF are unlikely to play any role in the neurochemical effects of high doses ofd-F in rats.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02245839
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  • 113
    Electronic Resource
    Electronic Resource
    D4 dopamine receptor binding affinity does not distinguish between typical and atypical antipsychotic drugs (1995)
    Springer
    Psychopharmacology 120 (1995), S. 365-368 
    Details
    ISSN: 1432-2072
    Keywords: Antipsychotic drugs ; D4 dopamine receptor ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The affinities of 13 atypical and 12 typical antipsychotic drugs for the cloned rat D4 dopamine receptor and the D4/D2 ratios were examined. Of the atypical antipsychotic drugs tested, only clozapine, risperidone, olanzapine, zotepine and tiospirone had affinities less than 20 nM. In fact, many atypical antipsychotic drugs had relatively low affinities for the cloned rat D4 receptor, with Ki values greater than 100 nM (Seroquel, fluperlapine, tenilapine, FG5803 and melperone). Additionally, several typical antipsychotic drugs had high affinities for the cloned rat D4 receptor, with Kis less than 20 nM (loxapine, chlorpromazine, fluphenazine, mesoridazine, thioridazine and trifluoroperazine). The ratios of D2/D4 affinities did not differentiate between these two types of antipsychotic drugs. Thus, D4 dopamine receptor affinity, used as a single measure, does not distinguish between the group of typical and atypical antipsychotic drugs analyzed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02311185
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  • 114
    Electronic Resource
    Electronic Resource
    Post-synaptic 5-HT1A receptor involvement in yawning and penile erections induced by apomorphine, physostigmine and mCPP in rats (1995)
    Springer
    Psychopharmacology 120 (1995), S. 376-383 
    Details
    ISSN: 1432-2072
    Keywords: Yawning ; Penile erections ; 5-HT1A agonists ; Tertatolol ; pCPA ; Apomorphine ; Physostigmine ; mCPP ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Apomorphine and mCPP induced yawning associated with penile erections in rats, whereas physostigmine induced only yawns. Apomorphineinduced yawning and penile erections were antagonized by low doses of raclopride, whereas physostigmineinduced yawning and mCPP-induced effects were only partly inhibited at high doses of raclopride. Scopolamine as well as clozapine antagonized yawning and penile erections induced by apomorphine, mCPP and physostigmine. Similarly, the 5-HT1A agonists 8-OH-DPAT and S 14506 inhibited yawning and penile erections induced by apomorphine, mCPP and physostigmine, and at similar doses induced lower lip retraction and hyperreactivity to handling. The β/5-HT1A antagonist tertatolol reversed the inhibitory effects of 8-OH-DPAT and S 14506 on drug-induced yawning and penile erections and increased apomorphine-and physostigmine-induced yawn frequency but not penile erection frequency. Like tertatolol, propranolol increased apomorphine- and physostigmine-induced yawn frequency, whereas ICI 118551 increased only physostigmine-induced yawning. 8-OH-DPAT-and S 14506-induced lower lip retraction and hyperre-activity to handling were also significantly antagonized by tertatolol. Finally,p-chlorophenylalanine pretreatment produced about 95% depletion in 5-HT in hypothalamus, hippocampus, striatum and frontal cortex and modified neither the responses of the inducing drugs nor the inhibitory effects of 8-OH-DPAT and S 14506 on drug-induced yawning and penile erections. These data suggest (i) that a final cholinergic mechanism blocked by scopolamine and clozapine is involved in drug-induced yawning and penile erections, (ii) that the effects of S 14506 depend upon stimulation of 5-HT1A receptors, (iii) that the inhibitory effects of 5-HT1A agonists on yawning and penile erections probably occurred at final steps on the pathways involved in the expression of yawning and penile erections and that these effects could be related to other effects of the 5-HT1A agonists, (iv) that a tonic inhibitory β influence could interfere with the expression of yawning but not with that of penile erections and (v) that presynaptic 5-HT1A receptors do not seem to play an important role in the inhibitory effects of 5-HT1A agonists on drug-induced yawning and penile erections in rats.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02245808
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    The ambivalent behaviour “stretched approach posture” in the rat as a paradigm to characterize anxiolytic drugs (1995)
    Springer
    Psychopharmacology 121 (1995), S. 81-90 
    Details
    ISSN: 1432-2072
    Keywords: Stretched approach posture ; Ambivalent behaviour ; Intention movements ; Ethological observation ; Rat ; Anxiety disorders ; Benzodiazepines ; 5-HT1A receptor agonists ; 5-HT uptake inhibitors ; Clonidine ; Clorgyline ; Anxiogenic drugs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effect of various psychotropic drugs on the ambivalent behaviour “stretched approach posture” (SAP) in the rat was assessed. SAP was elicited after a mild startle reaction due to physical contact with an electrified prod at one end of a straight runway. Using ethological observation methods, SAP as well as intention movements, prod contact, crossings, rearing, exploration, grooming and immobility were recorded. The benzodiazepine receptor agonists chlordiazepoxide, diazepam and alprazolam, the 5-HT1A receptor agonists flesinoxan and ipsapirone and the 5-HT uptake inhibitor clomipramine selectively (no effect on crossings) reduced SAP. Except for alprazolam, these drugs also reduced intention movements. In addition, chlordiazepoxide and diazepam enhanced prod contact. Reductions of SAP and intentions with concomitant reductions of crossings (nonspecific anti-ambivalent effects) were established for the α2-adrenoceptor agonist clonidine and the MAO inhibitor clorgyline. The 5-HT uptake inhibitor fluvoxamine suppressed intention movements, but not SAP. The mixed 5-HT/NA uptake inhibitor imipramine did not significantly affect SAP or intentions, but reduced crossings. The 5-HT2C/1B receptor agonist m-CPP, the inverse BZD receptor agonists FG 7142 and DMCM, and the α2-adrenoceptor antagonist yohimbine, to all of which putative anxiogenic effects have been ascribed, had no effect on SAP directed towards the prod. m-CPP, however, produced an increase in the stretched posture directed away from the prod (SAwayP). FG 7142 reduced intentions while strongly enhancing immobility (freezing). SAwayP and/or freezing may possibly reflect anxiogenic properties of drugs. The putative anxiogenic drug pentylenetetrazol false positively reduced SAP while increasing exploration. The dopamine-D2 receptor antagonist haloperidol and the catecholamine releaserdl-amphetamine had no effect on ambivalent behaviour. The muscarine receptor antagonist scopolamine reduced SAP and intentions while stimulating crossings. Finally, the 5-HT2C receptor antagonist ritanserine, the CCKA receptor antagonist devazepide, the CCKB receptor antagonist L-365.260 and the strychnine-insensitive glycine site antagonist 7-Cl-kynurenic acid were without effect on the behaviours in this paradigm using single doses. In conclusion, SAP and intention movements were reduced selectively by anxiolytic agents from different classes, including benzodiazepine receptor agonists, 5-HT1A receptor agonists and a 5-HT uptake inhibitor, whereas an α2-adrenoceptor agonist and a MAO inhibitor reduced SAP non-selectively. SAP in relation to other behaviours may therefore serve as a valuable paradigm to characterize anxiolytic drugs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02245594
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    Scopolamine prevents augmentation of stereotypy induced by chronic methamphetamine treatment (1995)
    Springer
    Psychopharmacology 121 (1995), S. 158-163 
    Details
    ISSN: 1432-2072
    Keywords: Methamphetamine ; Behavioral sensitization ; Scopolamine ; Acetylcholine ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Cholinergic neurotransmission has been implicated in various forms of neural plasticity such as kindling and learning. We have previously shown that blockade of muscarinic cholinergic receptors prevents the development of locomotor sensitization to methamphetamine. The present study was conducted to examine whether scopolamine, a muscarinic cholinergic antagonist, would also block augmentation of stereotypy induced by chronic methamphetamine (MA) treatment. Rats treated with MA (2.5 mg/kg, SC) for 10 days indicated significantly enhanced stereotyped behavior when tested with MA (2.5 mg/kg) after a 7-to 8- day withdrawal. Pretreatment with scopolamine (3 mg/kg) prior to MA administration prevented the augmentation of stereotypy. Rats treated with scopolamine alone showed no difference in MA-induced stereotypy compared to those treated with saline. Scopolamine methylbromide, a derivative of scopolamine that does not easily cross the blood-brain barrier, had no effect on the augmentation of stereotypy. These results suggest that stimulation of central muscarinic cholinergic receptors plays a role in the development of sensitization to the stereotypy stimulating effect of methamphetamine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02245625
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  • 117
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    Changes in the acoustic startle response and prepulse inhibition of acoustic startle in rats after local injection of pertussis toxin into the ventral tegmental area (1995)
    Springer
    Psychopharmacology 119 (1995), S. 71-78 
    Details
    ISSN: 1432-2072
    Keywords: Acoustic startle response ; Prepulse inhibition ; Schizophrenia ; Mesocorticolimbic DA system ; Dopamine ; Serotonin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effect of local injection of pertussis toxin (PTX) into the ventral tegmental area (VTA) on acoustic startle in rats was investigated. The PTX treatment caused only minor effects of its own on the acoustic startle response (ASR) or prepulse inhibition (PPI) of acoustic startle. However, systemic treatment with the indirect DA receptor agonist, amphetamine (2 mg/kg, SC) caused a significant increase in ASR magnitude and a significant disruption of PPI in PTX-treated rats while no such effects were observed in sham-treated rats. Treatment with the direct DA receptor agonist, apomorphine (2 mg/kg, SC), caused a significant disruption of PPI, an effect that was observed in both PTX-and sham-treated rats. Treatment with the 5-HT1A receptor agonist, 8-OH-DPAT (0.5 mg/kg, SC), did not affect PPI in either group but caused a marked increase in ASR magnitude in sham-treated rats. Interestingly, this effect was blocked in PTX-treated rats. The present results suggest that local injection of PTX into the VTA causes an increased sensitivity to the behavioural effects of psychostimulants on acoustic startle and may also suggest that intact midbrain 5-HT1A receptors are essential for the effect of 5-HT1A agonists on acoustic startle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02246056
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    Sulpiride antagonizes the biphasic locomotor effects of quinpirole in weanling rats (1995)
    Springer
    Psychopharmacology 119 (1995), S. 299-304 
    Details
    ISSN: 1432-2072
    Keywords: Dopamine ; Autoreceptor ; Sulpiride ; Quinpirole ; Locomotion ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Low doses of dopamine (DA) agonists such as the D2 receptor subfamily agonist quinpirole are thought to stimulate DA autoreceptors selectively, thereby inhibiting locomotor activity. High doses of quinpirole initially suppress and later activate locomotion during a single test session; the activation is presumably due to stimulation of postsynaptic receptors. The aim of this study was to investigate whether pretreatment with a selective DA D2 receptor antagonist, sulpiride, could block the putative autoreceptor-mediated inhibition at a lower dose than was required to block the postsynaptically mediated activation. Male and female 30-day-old rats were injected SC with one of eight doses of sulpiride (0.313–40 mg/kg) or the vehicle. Sixty minutes later, rats were injected SC with 0.2 mg/kg quinpirole or the vehicle. Five minutes after the second injection, rats were placed in automated activity monitors which recorded locomotor behavior for 60 min at 5-min intervals. Quinpirole at this dose first suppressed and later increased locomotor activity. Sulpiride pretreatment dose-dependently reversed both the early inhibition and later activation of quinpirole-induced locomotion. However, sulpiride did not block the quinpirole-induced early suppression at a lower dose than was required to block the later activation. Thus, there was no evidence that the locomotor suppression elicited by quinpirole is mediated by a more sensitive subset of DA receptors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02246295
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    State-dependent effects of atypical benzodiazepine-receptor agonists (1995)
    Springer
    Psychopharmacology 119 (1995), S. 399-404 
    Details
    ISSN: 1432-2072
    Keywords: Rat ; State-dependency ; Diazepam ; FG 8205 ; Zolpidem ; Agonist ; Partial agonist ; Benzodiazepine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The state-dependent effect of the BZ-receptor agonist diazepam (1.25–10 mg/kg), the partial agonist FG 8205 (0.5–4.0 mg/kg) and the BZ1-receptor agonist zolpidem (0.25–2 mg/kg) were investigated in rats. During daily sessions, animals were trained to acquire FR10 lever pressing for food reinforcement whilst under the influence of the agonists, using an operant technique. Forty-eight hours after the final training session under drug, their performance of the FR10 was evaluated during a test session, carried out following vehicle administration only. Neither diazepam, nor FG 8205 impaired acquisition of the task. In the group treated with 2 mg/kg zolpidem, six out of eight rats failed to learn within 20 sessions, but the smaller doses were without effect on acquisition. When drug treatment was withdrawn, there was evidence that all three of the agonists tested produced state-dependency. This was apparent in the form of longer latencies to obtain reinforcement and decreased lever pressing rates. The significance of these findings are discussed in the context of the relationship between the state-dependent effects of BZ-receptor agonists and their other properties, and the receptor subtypes which might underly these effects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02245855
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    The effects of repeated treatment with 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) on the lever press responding of the rat under FI and DRL schedules of food reinforcement (1995)
    Springer
    Psychopharmacology 120 (1995), S. 81-92 
    Details
    ISSN: 1432-2072
    Keywords: Serotonin1A agonist ; 8-OH-DPAT ; Lever pressing ; Stimulant ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In general, the effects of 8-OH-DPAT on the body temperature of rats or in inducing the 5-HT syndrome show rapid tolerance. However, in contrast, the 8-OH-DPAT-induced increase in the activity of rats in a two-way active avoidance task only occurs after repeated administration, i.e. there is sensitisation. The present study was conducted to examine whether this developing hyperactivity may also be expressed as increased rates of lever press responding, and if so, under which conditions it occurs. Rats were trained to press levers under fixed interval 60-s (FI 60) or differential reinforcement of low rates 20-s or 72-s (DRL20, DRL72) schedules of food reinforcement. Groups of trained rats were then treated daily 5 min before testing with doses of 0.01, 0.1 and 1.0 mg/kg 8-OH-DPAT SC for 10–21 days. In all three procedures, in the first couple of days of drug treatment, 8-OH-DPAT generally suppressed lever pressing in a dose-dependent manner. Thereafter, tolerance to this effect was seen to a greater (DRL20, DRL72) or lesser (FI60) extent. Some evidence for stimulation of low rates of lever press responding was seen after 10 days treatment under FI60, but not in DRL20 or DRL72 during short 30 to 60 min long daytime tests although in the latter case, the rats responded to the stimulating effects of 0.8 mg/kg SC amphetamine administered once at the end of the experiment. However, when rats were allowed to respond under DRL72 testing for 12 h during the night, after 10 days treatment a clear stimulation of lever pressing was observed. This stimulation was not specific to lever pressing, however, since a stimulation of entries into the food tray and licking were also seen. From these results, it may be concluded that the stimulating effect of 8-OH-DPAT after repeated administration may be expressed as increased rates of lever pressing, but not under all conditions in which psychomotor stimulation by amphetamine is seen. The potential for 8-OH-DPAT and related compounds to stimulate motor responding in this way should be taken into account when interpreting the effects of these drugs in animal models of psychiatric disorders.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02246148
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    The competitive NMDA antagonists CGP 43487 and APV potentiate dopaminergic function (1995)
    Springer
    Psychopharmacology 118 (1995), S. 310-315 
    Details
    ISSN: 1432-2072
    Keywords: MK-801 ; APV and CGP 43487 ; Apomorphine-induced behavior ; Motor activity ; Rota-rod test ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The administration to rats of different doses of the non competitive NMDA receptor blocker MK-801 (0.03–1 mg/kg IP) induced stimulation or reduction of locomotor activity, depending on the dose, whereas the competitive NMDA antagonists CGP 43487 (0.188–6 mg/kg IP) and APV (2.5–20 μg/rat ICV) inhibited locomotion at the highest doses. Unlike MK-801 and APV treatment, the administration of CGP 43487 did not induce impairment of rota-rod test performance. Both competitive and non-competitive NMDA antagonists, at doses devoid of any behavioral effect per se, potentiated the responses elicited by apomorphine (0.25 mg/kg SC). In particular, the occurrence of episodes of licking was weakly affected by MK-801 administration, but significantly increased by CGP 43487 and APV treatment; the presence of gnawing was augmented by all the pretreatments; sniffing, locomotion, grooming and rearing occurrence were not affected by the administration of NMDA antagonists. The results suggest that the competitive antagonists which facilitated dopaminergic function without causing motor impairment could be useful supplements in the treatment of Parkinson's disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02245960
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    Retarded acquisition of a temporal discrimination following destruction of noradrenergic neurones by systemic treatment with DSP4 (1995)
    Springer
    Psychopharmacology 118 (1995), S. 332-337 
    Details
    ISSN: 1432-2072
    Keywords: Noradrenaline ; DSP4 ; Operant behaviour Timing ; Interval bisection procedure ; Acquisition ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This experiment examined the effect of destroying central noradrenergic neurones, using the selective neurotoxin DSP4 (N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine) on the acquisition and performance of discrimination between two time intervals. Rats that had received systemic treatment with DSP4 and vehicle-treated control rats were trained in a series of discrete trials to press lever A following a 2-s presentation of a light stimulus and lever B following an 8-s presentation of the same stimulus. Both groups acquired the discrimination (〉90% correct choices) within 15 sessions; however, the DSP4-treated group showed significantly slower acquisition than the control group. When stable performance had been attained, ‘probe’ trials were introduced in which the light was presented for intermediate durations. Both groups showed sigmoid functions relating percent choice of lever B to log stimulus duration. Neither the bisection point (duration corresponding to 50% choice of lever B) nor the Weber fraction differed significantly between the DSP4-treated and control groups. The levels of noradrenaline were markedly reduced in the neocortex and hippocampus of the DSP4-treated group, but the levels of dopamine and 5-hydroxytryptamine were not altered. The results indicate that noradrenaline depletion induced by DSP4 retarded the acquisition of temporal discrimination, but did not impair steady-state discriminative precision.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02245963
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  • 123
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    Involvement of intracellular calcium ions in the release of the fluorescent dye calcein by cholinergic and α-adrenergic agonists from rat parotid acinar cells (1995)
    Springer
    Pflügers Archiv 429 (1995), S. 555-560 
    Details
    ISSN: 1432-2013
    Keywords: Rat ; Parotid glands ; Salivary glands ; Calcein ; Amylase ; Secretion ; Carbachol ; Noradrenalin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Effects of cholinergic and adrenergic agonists on the secretion of the fluorescent dye calcein were examined to clarify the involvement of calcium ions in the secretion of calcein from acinar cells dispersed from the rat parotid gland. Addition of carbachol (CCh) and noradrenalin (NA), but not isoproterenol (IPR), enhanced the net release of calcein from acinar cells during the subsequent 10 min in a dose range from 10−8 M to 10−6 M. The net release of calcein reached a maximum 7 min after the addition of CCh. The release of calcein was suppressed by the simultaneous additions of atropine with CCh, or phenoxybenzamine with NA. Addition of CCh induced a sustained dosedependent increase in the intracellular levels of calcium ions, ([Ca2+]i). Addition of NA at 10−6 M increased [Ca2+]i. Phenoxybenzamine completely inhibited the NA-induced increase, but propranolol did not. The removal of extracellular calcium ions did not influence the release of calcein induced by 10−6 M CCh, but it abolished the sustained increase in [Ca2+]i. The transient increase in [Ca2+]i induced by CCh was observed in the absence of extracellular calcium ions. A calcium ion chelator, 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid (BAPTA) inhibited the CCh-induced release of calcein. The calcium ionophore, A23187 (2.5×10−6 M), but not 10−3 M dibutyryl cAMP, evoked the release of calcein. It also increased [Ca2+]i. Removal of extracellular calcium ions suppressed the A23187-induced release of calcein. These results suggest that the release of calcein from parotid acinar cells is transiently induced through an increase in [Ca2+]i by muscarinic and α-adrenergic agonists and may represent the initial process of salivary secretion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00704161
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    Diffusion of myoglobin in skeletal muscle cells — dependence on fibre type, contraction and temperature (1995)
    Springer
    Pflügers Archiv 430 (1995), S. 519-525 
    Details
    ISSN: 1432-2013
    Keywords: Diffusion coefficient ; Muscle cells ; Myoglobin ; Microinjection ; Oxygen ; Facilitated diffusion ; Intracellular oxygen transport ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We measured the diffusion coefficient of myoglobin (D Mb) inside mammalian skeletal muscle cells with a microinjection technique. A small bolus of horse Mb was injected into a single muscle fibre and the subsequent time-dependent changes of the Mb profiles along the fibre axis were measured with a microscope-photometer. For fibres of the rat soleus muscle at 22° C, a D Mb of 1.3·10−7 cm2/s was found, confirming a result obtained previously by us for rat diaphragm muscle with a photo-oxidation technique. In the extensor digitorum longus muscle of the rat, a higher value of 1.9 · 10−7 cm2/s was measured. Auxotonic muscle contractions did not change the apparent D Mb. For the temperature range between 22 ° C and 37 ° C, a temperature coefficient, Q 10, of 1.5 was calculated. The implication of this result for the role of Mb in the facilitation of oxygen transport was examined. Model calculations show that with this relatively low D Mb value, the intracellular oxygen supply can be improved only slightly.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00373888
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    Promotion of sleep by heat in young rats (1995)
    Springer
    Pflügers Archiv 430 (1995), S. 729-738 
    Details
    ISSN: 1432-2013
    Keywords: Sleep ; Thermoregulation ; Slow wave activity ; Sleep drive ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The aim of the experiments was to study the effects of a moderate heat load on sleep in young (26-day-old) rats and to determine whether the sleep-promoting effect of heat results from stimulation of the homeostatic sleep process. The changes in sleep-wake activity, electroencephalogram slow wave activity (SWA) during non-rapid eye movement sleep (NREMS) and cortical temperature (T crt) were determined during and after long (24-h) and short (2.5-h) heat loads (elevation of ambient temperature from 26° C to 32° C), and after total sleep deprivation (SD) combined with a short-term heat load. The heat exposures elicited increases in T crt and rectal temperature (2 and 1.7° C respectively). The long-term heat load induced persistent, albeit slight enhancements in NREMS. Rapid eye movement sleep (REMS) increased with a 12-h delay during the 24-h heat load. Heat elicited an immediate large increase in SWA. After this initial increase, SWA declined and tended to fall below the baseline level during the last 12 h of the 24-h heat load. SWA and REMS were significantly suppressed after termination of 24-h heat loading. The increased SWA during the short-term heat load was not followed by subsequent alterations in sleep when the ambient temperature had returned to normal. However, after the combination of SD with the shortterm heat load the durations of NREMS and SWA were significantly enhanced compared with those found after SD at 26° C. The results are interpreted as suggesting that heat increases NREMS in the young rat by the same mechanism as is involved in the enhancement of NREMS after SD: a stimulation of sleep drive.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00386168
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    Effects of hypobaric hypoxia on histochemical fibre-type composition and myosin heavy chain isoform component in the rat soleus muscle (1995)
    Springer
    Pflügers Archiv 429 (1995), S. 601-606 
    Details
    ISSN: 1432-2013
    Keywords: Hypobaric hypoxia ; Histochemistry ; Muscle fibre-type ; Electrophoresis ; Myosin heavy chain isoform ; Soleus muscle ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Histochemical fibre-type composition and myosin heavy chain isoform component in the soleus muscle were studied in normoxic rats at postnatal ages of 5, 10, 15, and 20 weeks and in rats exposed to hypobaric hypoxia (460 torr) for 5 weeks from postnatal ages of 5, 10, and 15 weeks. The increase in the percentage of type I fibres and the concomitant decrease in that of type IIa fibres in the soleus muscle of normoxic rats were observed until 15 weeks of age. On the other hand, no change in the fibre-type composition of the muscle during postnatal development was observed in hypoxic rats, irrespective of the age at which they were exposed to hypoxia. The changes in the myosin heavy chain isoform component (MHC I and MHC IIa) of the muscle during postnatal development and by hypoxia corresponded well with those in the muscle fibre-type composition. It is concluded that hypobaric hypoxia inhibits the growth-related shift of muscle fibre-types from type IIa to type I and of myosin heavy chain isoforms from MHC IIa to MHC I in the rat soleus muscle, and that there are no changes in the muscle fibre-type composition or the myosin heavy chain isoform component caused by hypoxia after the shifts in these parameters which occur during postnatal development are completed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00373980
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    Cervical sympathectomy affects gonadotropin-releasing hormone, luteinizing hormone and testosterone in male rats (1995)
    Springer
    Journal of anesthesia 9 (1995), S. 166-169 
    Details
    ISSN: 1438-8359
    Keywords: Cervical sympathectomy ; Stellate ganglion block ; Gonadotropin ; Testosterone ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To examine the effects of bilateral cervical sympathectomy on the secretion of gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH) and testosterone (TS), 24 male rats were divided into four groups: control (C), light (L), sympathectomy (S), and light-sympathectomy (LS) groups. The C and S groups were kept under a 12-h light-dark cycle and the L and LS groups were kept under continuous light for 2 weeks. After 2 weeks, blood was collected and the rats were perfused with a fixative. GnRH neurons in the hypothalamus were stained immunohistochemically, and serum LH and TS levels were measured by radioimmunoassay. Although the difference in the number of GnRH neurons between the C and S groups was not significant, the L group was significantly lower than the C or LS groups. The serum LH and TS levels in the L group were higher than in the other groups. The present results suggest that continuous light increases GnRH secretion in the hypothalamus, followed by increased secretions of LH in the pituitary and TS in the testes, and bilateral cervical sympathectomy under continuous light inhibits these hormonal changes. However, a normal circadian rhythm does not affect gonadotropin secretion. Therefore, long-term and repeated stellate ganglion block may inhibit the increases of GnRH, LH, and TS secretions induced by continuous light.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02479850
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    Visualization of the NMDA recognition site in rat and mouse spinal cord by [3H]CGS 19755in vitro autoradiography (1995)
    Springer
    Amino acids 9 (1995), S. 247-263 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; NMDA receptors ; CGS 19755 ; TCP ; Spinal cord ; Rat ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The possibility to visualize the NMDA recognition site with [3H]CGS 19755in vitro autoradiography was evaluated in rat brain and spinal cord sections and thereafter used to study the distribution of the NMDA recognition site in rat and mouse spinal cord. The [3H]CGS 19755 binding was concentrated to the dorsal horn, in particular to the substantia gelatinosa. Notable binding was also seen in the intermediate area and ventral horn, while some binding was observed in the funiculi. No major differences were seen in [3H]CGS 19755 binding at various levels of the rat or mouse spinal cord, although a more dense binding was seen in the mouse. A similar distribution of the [3H]CGS 19755 specific binding and the NMDA receptor associated ion-channel site, labeled with [3H]TCP, was found in the mouse spinal cord. Taken together, our data indicate that the NMDA recognition site can be visualized in rat and mouse spinal cord byin vitro [3H]CGS 19755 autoradiography.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00805956
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    Effect of infra-red low-power laser irradiation on regeneration of myelinated axons (1995)
    Springer
    Lasers in medical science 10 (1995), S. 273-277 
    Details
    ISSN: 1435-604X
    Keywords: Ga-As laser ; Myelinated fibre regression ; Rat ; Sciatic nerve
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Physics , Technology
    Notes: Abstract The purpose of the present study was to examine the regeneration of myelinated axons under the effect of laser irradiation at various wavelengths and energy densities. Laser irradiation at 890 nm with an energy dose of 0.33 J cm−2 as well as He-Ne laser irradiation failed to change the number of regenerating myelinated axons in distal nerve stumps on the 30th day after cutting the nerve. An increase of dose delivered to the skin to 9.33 J cm−2 resulted in a 49% decrease in the number of myelinated axons. A 24% suppression of nerve regeneration was also registered using 1220 nm wavelength laser (dose 0.98 J cm−2). This phenomenon is likely to be attributed to the stimulating effect of laser irradiation of the near-infra-red range on proliferation of fibroblasts and scar formation. 1220 nm of 7.2 J cm−2 dose effected neither the growth nor the myelinization of axons in distal nerve stumps on the 20th day following nerve damage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02133620
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    Somatostatin receptors mediating inhibition of basal and stimulated electrogenic ion transport in rat isolated distal colonic mucosa (1995)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 352 (1995), S. 402-411 
    Details
    ISSN: 1432-1912
    Keywords: Electrogenic ion transport ; Rat ; colonic mucosa ; Somatostatin (SRIF) ; BIM-23027 ; BIM-23056 ; L-362855 ; Seglitide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The aim of this study was to examine the potencies of several recently identified selective somatostatin (SRIF)-receptor ligands as inhibitors of electrogenic ion transport in the rat distal colonic mucosa with the view to identifying the SRIF receptor type involved. Under basal conditions, cumulative administration of SRIF and SRIF2g decreased short circuit current (SCC), a measure of electrogenic ion transport, with EC50 values of 4 nM and 9 nM respectively. The peptidase inhibitors, phosphoramidon (1 μM) and amastatin (10 μM), had no effect on the potencies of either SRIF or SRIF28. The inhibitory action of SRIF on basal SCC was suppressed by piretanide and diphenylamine-2-carboxylate, compatible with the assumption that the Na+K+2Cl− co-transporter and Cl− channels, respectively, may be involved in this antisecretory action of SRIF. Tetrodotoxin (1 μM) had no effect on the antisecretory action of SRIF, suggesting that the process was not neuronally mediated. All of the SRIF analogues examined, with the exception of BIM-23056, maximally inhibited basal SCC to a similar extent as SRIF. Seglitide and octreotide were both more potent antisecretory agents than SRIF (respective EC50 values, 0.4 nM and 1.5 nM) suggesting that this effect was mediated by a receptor belonging to the SRIF1 receptor group. The most distinguishing feature of the rank order of agonist potencies was the high potency of the selective sst2 receptor ligand, BIM-23027 (EC50, value 0.32 nM), the weaker potency exhibited by the selective sst5 receptor ligand, L-362855 (EC50 value 21 nM), and the lack of agonist activity displayed by the selective sst3 receptor ligand, BIM-23056 (EC50 value 〉 1000 nM). This profile is comparable with that observed in binding studies on the recombinant sst2 receptor. Forskolin-stimulated secretion was suppressed by SRIF analogues with the rank order of agonist potencies BIM-23027 〉 SRIF 〉 L-362855 〉 BIM-23056 which resembled that exibited under basal conditions. However, the absolute potencies of these agonists were lower (respective EC50 values 2 nM, 14 nM, 38 nM and 〉 1000 nM) whilst the magnitude of inhibition was about three fold greater. BIM-23027 and SRIF (both 30 nM) also inhibited carbachol-stimulated increases in basal SCC by 60–70%, while a similar concentration of L-362855 inhibited these responses by 11 %. BIM-23056 (1 μM) had no effect on carbachol-simulated secretion. Radioligand binding studies on rat colonic mucosal membranes using [125I]-Tyr11-SRIF suggested heterogeneity of SRIF binding sites. Thus, SRIF and SRIF28 competed for binding (IC50 values, 0.32 and 0.63 nM, respectively) with Hill slopes less than unity; while seglitide and BIM-23027 both maximally displaced only 30–40% of specific binding with apparent high affinity (respective pIC50 values, 10.1 nM and 10.0). In conclusion, SRIF decreases basal as well as both cAMP and Ca2+-dependent Cl− secretion in rat colonic mucosa. The rank order of agonist potencies suggests that receptors resembling the recombinant sst2 receptor mediate inhibition of basal and forskolin-stimulated secretion. Radioligand binding studies suggest that BIM-23027 interacts with a sub-population of [125I]Tyr11-SRIF binding sites in rat colonic mucosal membranes which probably correspond to the receptors mediating the antisecretory effects described here.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00172777
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    Etofibrate suppresses neointima formation of the ballooned common carotid artery of rats (1995)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 352 (1995), S. 424-428 
    Details
    ISSN: 1432-1912
    Keywords: Balloon injury ; Carotid artery ; Fibrates ; Neointima ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The inhibition of neointima formation by drugs is a major goal to prevent restenosis following angioplasty. In the present study, the effect of etofibrate on blood lipids and vessel wall was investigated using a balloon injury rat model. Two weeks after ballooning the common carotid artery neointima formation was quantified by morphometric measurement of the neointimal area and cellularity in vessel cross sections, and by fluorometric evaluation of the DNA content. Etofibrate (160 mg/kg/day) had no effect on plasma triglyceride levels, but reduced serum cholesterol by about 25%. The injury-induced increase of both the neointimal area and the DNA-content was significantly inhibited by 47% (P 〈0.005) and 34% (P 〈0.05), respectively, in the drug-treated animals in comparison to the untreated control rats. The ratio of neointima and media was significantly (P 〈 0.001) reduced from 152.9 ± 11.6% (controls) to 82.84 ± 12.59% in the etofibrate-treated group. The cellularity (numerical profile and volume density of nuclei) in the neointima was similar in both groups. In conclusion, injury-induced neointima formation is reduced in etofibrate-treated animals, which could be due to an inhibition of smooth muscle cell proliferation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00172780
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  • 132
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    Developmental variation of the permeability to Ca2+ of AMPA receptors in presumed hilar glial precursor cells (1995)
    Springer
    Pflügers Archiv 431 (1995), S. 244-252 
    Details
    ISSN: 1432-2013
    Keywords: Rat ; Hippocampus ; Hilus ; Glutamate ; Kainate ; Patch-clamp in situ
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Glial cells in the hilus of the dentate gyrus of the rat were investigated using the patch-clamp technique in acute slices of the hippocampal formation. According to their voltage-gated current patterns, two classes of glial cells — putative astrocytes and presumed glial precursor cells — were apparent. The glutamate receptor agonists kainate, glutamate, and α-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) evoked inward currents at a holding potential of −70 mV in astrocytes and presumed glial precursor cells. Inward currents could also be induced in nucleated patches, indicating a direct action on glial receptors. In presumed hilar glial precursor cells, 6,7-dinitroquinoxaline-2,3-dione (DNQX; 10 μM) blocked the kainate-induced current, while it was partially inhibited by Zn2+ (2 mM) and Evans Blue (10 μM). Cyclothiazide (100 μM), in contrast, potentiated this current, indicating the presence of AMPA receptors. In 90% of the presumed glial precursor cells the excitatory amino-acid-evoked current voltage (I/V) relations were linear or outwardly rectifying and reversed close to 0 mV, which is characteristic for non-specific cation channels. To determine the permeability to Ca2+, I/V relations were determined in a Na+-free solution containing 40 mM Ca2+ and showed reversal potentials of a wide variation ranging from −63 mV to + 1 mV with corresponding P Ca/ P Cs permeability ratios of between 0.09 and 2.10. Statistical analysis revealed that the permeability to Ca2+ significantly decreased with an advance in age (r=−0.596; n=21; P〈0.01). These data suggest that the Ca2+ influx mediated by the activation of AMPA receptors expressed in presumed hilar glial precursor cells is dependent on the developmental stage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00410197
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    Measures of “fastness”: force profiles of twitches and partly fused contractions in rat medial gastrocnemius and tibialis anterior muscle units (1995)
    Springer
    Pflügers Archiv 431 (1995), S. 230-236 
    Details
    ISSN: 1432-2013
    Keywords: Rat ; Motor unit ; Isometric contraction ; Speed
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Recordings of isometric force were obtained for twitches and (sub)maximal tetani of gastrocnemius medialis (MG) and tibialis anterior (TA) muscle units in female Wistar rats. We assessed the relationships between unit properties that have all been associated with “speed”: (1) the relative degree of peak force attained during repetitive activation at 40 Hz (P 40/P max), (2) the relative degree of final twitch fusion during the same test burst (Fus-end), and (3) various measures of the time-course of single twitches, including twitch time-to-peak and a parameter referred to as “initial fusion ratio” (Fus-in; relative decline from peak force at 25 ms from twitch onset). The various measures of twitch time-course were significantly correlated to each other with correlation coefficients varying over a fairly wide range (0.35–0.64 for MG; 0.50–0.80 for TA). Twitch time-course was also significantly correlated with Fus-end during the 40-Hz repetitive activation; the highest correlation coefficient (0.69 for MG, 0.80 for TA) was obtained for Fus-in, which was also numerically similar to Fus-end. Thus, the degree of fusion indeed seemed to be largely dependent upon aspects of twitch time-course. However, the relative degree of force mobilization obtained in the same contractions elicited by stimulation at 40 Hz was not consistently better correlated with Fus-end than with measures of single twitch time-course. Furthermore, in fast-twitch units having the same twitch time-to-peak, the force mobilization elicited by stimulation at 40 Hz (P 40 P max) was the same for MG and TA, while the degree of fusion was significantly smaller for TA than for MG units. The results demonstrate the complexity of the concept of isometric “speed” and underline the need for using several speed indicators in parallel in studies concerning the differentiation of muscle (unit) properties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00410195
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    Inhibitory mechanisms in epileptiform activity induced by low magnesium (1995)
    Springer
    Pflügers Archiv 430 (1995), S. 238-245 
    Details
    ISSN: 1432-2013
    Keywords: Epilepsy ; Epileptiform activity ; Mg2+-free media ; Low magnesium ACSF ; PDS afterpotentials ; Inhibition ; Hippocampus ; Rat ; GABA ; Ca2+-dependent K+ current
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In rat hippocampal slices epileptiform activity was induced by superfusion with Mg2+-free artificial cerebrospinal fluid (ACSF). Paroxysmal depolarization shifts (PDS) were evoked by electrical stimulation of Schaffer collaterals. To investigate the afterpotentials that follow PDS, intracellular recordings were made from CA1 pyramidal cells. The experiments revealed that several components are engaged in the generation of PDS afterpotentials in Mg2+-free ACSF. A long lasting component which determined the overall duration of the PDS afterhyperpolarization was blocked by intracellular application of ethylenebis(oxonitrilo)-tetraacetate (EGTA); concomitantly, the afterhyperpolarizations following depolarizing current injections were blocked. This indicated that the long lasting component was due to a slow Ca2+-activated K+ current. The block of Ca2+-activated K+ current uncovered a depolarizing PDS afterpotential with an N-shaped voltage dependence, suggesting that this depolarizing afterpotential component may be due to an N-methyl d-aspartate (NMDA) conductance. Intracellular injection of Cl− revealed that the PDS were followed by Cl− currents lasting about 500 ms. This component could be blocked by application of bicuculline suggesting that it is due to a synaptically GABA-mediated (i.e. γ-aminobutyric acid) Cl− current. A comparison of PDS afterpotentials in Mg2+-free ACSF and those in other models of epileptiform activity suggests that similar sequences of inhibitory components are activated in spite of different pharmacological alterations of membrane conductances which induce the epileptiform discharges.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00374655
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    Growth, hormonal status and protein turnover in rats fed on a diet containing peas (Pisum sativum L.) as the source of protein (1995)
    Springer
    Plant foods for human nutrition 47 (1995), S. 211-220 
    Details
    ISSN: 1573-9104
    Keywords: Hormonal status ; Legume diet ; Pisum sativum L. ; Protein turnover ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The inclusion of peas (Pisum sativum L.) as the source of protein in the diet of growing rats brings about a reduction in growth rate as well as the impairment in the liver, muscle and spleen weights as compared with casein fed controls. Also, a fall in plasma glucose, triglycerides and protein was observed in the legume fed animals, while no changes in cholesterol levels were found. Furthermore, the rats fed on the diet containing peas showed lower levels of plasma insulin, corticosterone, IGF-I and T4 as compared with casein controls. Liver and muscle total protein (mg) and total DNA (mg) were markedly decreased in the legume fed animals, but DNA/g, protein/DNA and RNA/protein ratios were similar in both dietary groups. Likewise, liver and muscle fractional synthesis rates were similar in the casein and legume groups, while the whole body protein synthesis is assumed to be lower in the legume fed animals due to differences in body weights. It is concluded that animals fed on a diet containing peas (Pisum sativum L.) as the only source of protein showed less adverse effects than those found with other legumes such asVicia faba L. orPhaseolus vulgaris L., in which protein quality, antinutritional factors and nutrient availability could be involved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01088329
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    Comparative Tissue Distribution and Elimination of Amphotericin B Colloidal Dispersion (Amphocil®) and Fungizone® After Repeated Dosing in Rats (1995)
    Springer
    Pharmaceutical research 12 (1995), S. 275-283 
    Details
    ISSN: 1573-904X
    Keywords: Amphotericin B ; Amphocil® ; Fungizone® ; Colloidal Dispersion ; Tissue Distribution ; Pharmacokinetics ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The pharmacokinetic profiles of amphotericin B (AmB) after administration of Amphocil®, an AmB/cholesteryl sulfate colloidal dispersion (ABCD) and the micellar AmB/deoxycholate (Fungizone®) were compared after repeated dosing in rats. After administration of ABCD and Fungizone at an equal AmB dose (1 mg/kg), AmB concentrations in plasma and most tissues were lower for the ABCD dose, especially in the kidneys where reduced drug concentration correlated with reduced nephrotoxicity. In contrast, AmB concentrations in the liver were substantially higher when ABCD was administered; however, without an accompanying increase in hepato-toxicity. Daily administration of ABCD for 14 days did not lead to AmB accumulation in plasma; while a slight accumulation was observed after multiple administration of Fungizone. AmB was eliminated more slowly from the plasma and various tissues and urinary and fecal recoveries of AmB were reduced after ABCD administration. These results suggest that ABCD may be stored in tissues in a form that is less toxic and is eliminated from the systemic circulation by a different mechanism than the free and protein-bound AmB in plasma. AmB accumulation in the spleen was observed when higher doses of ABCD (5 mg/kg) were administered, which could be due to saturation of hepatic uptake of AmB. Comparison of spleen concentrations of AmB between ABCD and Fungizone® at 5 mg/kg AmB doses was not possible because of Fungizone's toxicity in rats. In all other organs, AmB concentrations reached or approached a steady state within two weeks of dosing with ABCD. Urinary and fecal clearances of AmB were not different between ABCD and Fungizone administration. In summary, the distribution and elimination characteristics of AmB in rats were substantially altered when it was administered as ABCD in comparison to Fungizone. Nephrotoxicity of AmB in rats was reduced after administration of ABCD apparently because of the altered tissue distribution pattern. Thus, ABCD (Amphocil®) may be a clinically beneficial formulation of AmB in patients with systemic fungal infections.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1016243313027
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    Isolation and culture of endothelial cells from the mesenteric vascular bed (1995)
    Springer
    Methods in cell science 17 (1995), S. 257-262 
    Details
    ISSN: 1573-0603
    Keywords: Endothelial cells ; Isolation ; Culture ; Mesentery ; Rat ; Rabbit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Methods are described for the enzymatic isolation of endothelial cells from rat and rabbit mesenteric arteries and veins. The mesenteric vascular bed is incubated with an enzyme solution containing collagenase, deoxyribonuclease, papain, dithiothreitol and bovine serum albumin for 45 min at 37 °C in a shaking waterbath. After the 45 min digestion, cells are centrifuged and plated. This method yields an endothelial cell population with a high plating efficiency which is relatively free of smooth muscle contamination.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00986231
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    Lactate dehydrogenase activity and isoform distribution in the rat pelvic ganglion: effects of diabetes and bladder outlet obstruction (1995)
    Springer
    Urological research 23 (1995), S. 395-399 
    Details
    ISSN: 1434-0879
    Keywords: Rat ; Pelvic ganglion ; Lactate dehydrogenase ; Isoforms ; Infravescial obstruction ; Diabetes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We have previously shown that the intramural motor nerves in the rat bladder can function in anoxic conditions. The present study aims to explore the distribution and activity of lactate dehydrogenase (LDH), the key enzyme for ATP generation in anoxia. The activity and isoform distribution pattern of LDH was studied in pelvic ganglia from male and female rats. A histochemical investigation showed that the LDH activity was intense in the ganglion cells, and weak in the other tissue components (nerve bundles, connective tissue). The male pelvic ganglion weighed 55% more than the female pelvic ganglion, the enzyme activity per unit ganglion weight was 60% higher and the total LDH activity was 155% higher. The isoform distribution was similar, with M4 being dominant isoform, followed by M3H. Infravesical outlet obstruction in the female rat induced a threefold increase in ganglion weight, and the total LDH activity increased twofold. In this hypertrophic female ganglion a decreased relative amount of M4, and an increased amount of MH3, was found. Diabetes in the male rat had no effect on ganglion weight or its contents and isoform distribution of LDH.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00698742
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  • 139
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    Effect of exposure to oxygen at 101 and 150 kPa on the cerebral circulation and oxygen supply in conscious rats (1995)
    Springer
    European journal of applied physiology 71 (1995), S. 475-484 
    Details
    ISSN: 1439-6327
    Keywords: Cardiovascular changes ; Hyperbaric O2 ; Microspheres ; Rat ; Regional cerebral blood flow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Hyperbaric oxygen at pressures of 300 to 500 kPa has been shown to induce changed distribution of cerebral blood flow ( $$\dot Q$$ CBF) in rats, in places reducing the supply of the supplementary O2. Thus, in the present study, the effect of hyperoxia at 101 (group 1, n = 9) and 150 (group 2, n = 9) kPa OZ on cerebral blood flow distribution and central haemodynamics was tested in conscious, habituated rats. During the control period the systolic arterial pressure (BPs), heart rate (f c), breathing frequency (f b), cardiac output ( $$\dot Q$$ c), arterial acid-base chemistry and glucose, as well as $$\dot Q$$ CBF distribution (r $$\dot Q$$ CBF) were similar in the two groups of animals. During O2 exposure, the acid-base chemistry remained unchanged. The haemoglobin decreased in group 2, but remained unchanged in group 1. The f c decreased rapidly in both groups during the change in gas composition, after which f c remained constant both in group 1 and in group 2, for whom pressure was increased. The $$\dot Q$$ c and f b decreased and BPs increased similarly in the two groups. Total $$\dot Q$$ CBF and r $$\dot Q$$ CBF decreased to the same extent in both groups, and the r $$\dot Q$$ CBF changes were equally scattered. In group 1, breathing of pure O2 did not increase the O2 supply to any cerebral region except to the thalamus and colliculi after 60 min, whereas the O2 supply to the hypothalamus decreased and remained low. In group 2, the O2 supply was unchanged compared to the control period in all regions. These findings agree with previous observations during exposures to higher O2 pressures. In air after O2 exposure the acid-base chemistry remained normal. The f c and f b increased to higher levels than during the control period. The BPs remained high. The brain blood flows were increased, inducing elevated O2 supply to several brain regions compared to the control period. In conclusion, O2 supply to the central nervous system was found to be in the main unchanged during breathing of O2 at 101 kPa and 150 kPa.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238548
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    Complex-radical terpolymerization of phenanthrene, maleic anhydride, and trans-stilbene (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 7-13 
    Details
    ISSN: 0887-624X
    Keywords: radical terpolymerization ; charge transfer complexes ; phenanthrene ; maleic anhydride ; trans-stilbene ; thermal stability ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The radical terpolymerization of the donor-acceptor-donor monomer system, phenanthrene (P) - maleic anhydride (M) - trans-stilbene (S), was studied. These monomers are known to be nonhomopolymerizable. The terpolymerization was carried out in p-dioxane and/or toluene at 70°C in the presence of benzoyl peroxide used as the initiator. P and S were found to form charge transfer complexes (CTC) with M in p-dioxane at 35°C. The results obtained are discussed in terms of the free monomer and complex propagation models. It is shown that terpolymerization is carried out at a stage close to binary copolymerization of two complexomers. The reactivity ratio of P … M and S … M complexes was estimated by the Kelen-Tüdös method. Absorbance ratios at 1770 cm-1 (vC=0 of anhydride group), 764 cm-1 (δCH in monosubstituted benzene of S), and 820 cm-1 (δCH in disubstituted benzene of P) as a function of terpolymer composition were established. P - M - S terpolymers are shown to have high thermal stabilities. © 1995 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1995.080330102
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    Electrical conductivity of poly(vinyl chloride) obtained by photodehydrochlorination from laminated poly(vinyl chloride)/polypyrrole films (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1375-1380 
    Details
    ISSN: 0887-624X
    Keywords: poly(vinyl chloride) ; electrical conductivity ; photodehydrochlorination ; laminated films ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(vinyl chloride) (PVC) has been converted to an electrically conductive structure by combined electrochemical and photochemical methods. PVC was cast on a polypyrrole (PPy) film electrode which had been electrochemically prepared. The PVC layer in the laminated PVC/PPy films was first dehydrochlorinated under the illumination of UV light, and the generated polyenes were subsequently doped with I2 and FeCl3. The maximum electrical conductivity achieved for such PVC film was 2.51 X 10-2 and 8.63 10-2 S cm-1 after I2 and FeCl3 doping, respectively. The temperature dependence of the electrical conductivity showed different behavior in higher and lower temperature ranges. In the former (T 〉 243 K), the T-1 law held, and the activation energy and bandgap were estimated as 0.25 and 0.49 eV, respectively. In the latter (T 〈 243 K), the conductivity mechanism followed the variable range hopping model (T-1/4 law) in which the radius of the localized state wave function and the density of the localized states at the Fermi level were 1.25 × 103 Å and 1.03 X 1015 eV-1 cm-3, respectively. © 1995 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1995.080330820
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    A novel way to study the initial stages of soap-free emulsion polymerizations: The intercalation of polystyrene oligomers into hydrotalcite (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1409-1417 
    Details
    ISSN: 0887-624X
    Keywords: emulsion polymerization ; oligomers ; polystyrene ; hydrotalcite ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The dominant species in the early stages of an emulsifier-free emulsion polymerization of styrene has been found to be an oligomer of two to three monomer units using a novel trapping technique. This involved the intercalation of charged primary oligomers between the layers of a hydrotalcite, [Mg4Al2(OH)12]2+[A]2- (where A = dianion). Hydrotalcites are an important class of lamellar, inorganic compounds whose interlayer spacing can be mod-ified by anion exchange. Our approach first involved preparing a hydrotalcite precursor in which the layers were propped apart by an organic dianion (terephthalate = TA). This material was then used to capture the negatively charged polystyrene oligomers from the emulsion polymerization reaction mixture. We found that TA was rapidly ion-exchanged for the charged oligomers.The resulting pillared hydrotalcite material was characterized using XRD and SEC. We found that the interlayer spacing between the hydroxide layers increased to 23.2 Å on exposure to the emulsion reaction mixture. This represents an interlayer expansion of 18.3 Å (after subtraction of the hydroxide layer contribution), which is cnsistent with intercalation of oligomers with two to three monomer units arranged in a bilayer. This size estimate was confirmed by the results of size exclusion chromatography. © 1995 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1995.080330901
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    Gamma-oxidation of linear low-density polyethylene: The dose-rate effect of irradiation on chemical and physical modifications (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1455-1460 
    Details
    ISSN: 0887-624X
    Keywords: γ-oxidation ; polyethylene ; FTIR ; molecular weight ; elongation at break ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: γ-Oxidation of linear low-density polyethylene based on hexene and butene was investigated. Irradiation was performed at different dose rates in air (from 2 rad/s to 100 rad/s). Degraded samples were analyzed with IR combined with NO and SF4 derivatizations. Our results showed that the lower the dose rate, the higher the degree of oxidation in terms of γ-product formation. Ketone species appeared to be the dominant γ-products. The G values of γ-product formation were very dependent on the dose rate of initiation. Comparison of the G value ratio of different γ-products revealed stoechiometry differences. The complex appearance and disappearance of unsaturations was tentatively explained. The modifications of elongation at break induced by γ-irradiation were monitored by molecular changes in weight. This was not conclusive because changes in elongation at break are inconsistent with changes in Mw/Mn. © 1995 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1995.080330906
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  • 144
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    Preparation and properties of alkylated poly(styrene-graft-ethylene oxide) (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1465-1474 
    Details
    ISSN: 0887-624X
    Keywords: grafting ; poly(styrene-graft-ethylene oxide) ; styrene-oxirane graft copolymers ; ethoxylation ; alkylation ; anionic polymerization of ethylene oxide ; poly(styrene-co-acryl-amide) ; crystallinity ; water absorption ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(styrene-graft-ethylene oxide), having alkyl chains (C12 or C18) on the polystyrene main chain or on the poly(ethylene oxide) (PEO) side chains, were synthesized. The main chain was alkylated by first ionizing amide groups in a styrene/acrylamide copolymer with tert-butoxide, and then using the amide anions as sites for reactions with 1-bromoalkanes. An excess of amide anions was used in the reaction, and the remaining anions were subsequently utilized as initiator sites for the anionic polymerization of ethylene oxide (EO). Synthesis of poly(styrene-graft-ethylene oxide) with alkylated side chains was accomplished by polymerization of EO onto the ionized styrene/acrylamide copolymer, followed by an alkylation of the terminal alkoxide anions with 1-bromoalkanes. The alkylated graft copolymers were structurally characterized by using elemental analysis, 1H NMR, GPC, and IR spectroscopy. DSC analysis showed that only graft copolymers with PEO contents exceeding about 50 wt % and side chain crystallinities comparable to those of homo-PEO. Main chain alkylated graft copolymers generally had higher crystalinities, as compared to nonalkylated and side chain alkylated samples. The graft copolymers absorbed water corresponding to one water molecule per EO unit at low PEO contents. The water absorption increased progressively at PEO contents above 30 wt % for main chain alkylated samples and above 50 wt % for non-alkylated samples. © 1995 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/pola.1995.080330908
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    Surface nonhomogeneity in radiation grafted FEP-g-polystyrenesulfonic acid proton exchange membranes (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1419-1429 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No Abstract
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1995.080330916
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  • 146
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    Complex-radical terpolymerization of allylglycidyl ether, maleic anhydride, and methyl methacrylate: Design of self-crosslinking macromolecules (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1447-1454 
    Details
    ISSN: 0887-624X
    Keywords: terpolymerization ; charge transfer complex ; allylglycidyl ether ; maleic anhydride ; methyl methacrylate ; thermo-crosslinking ; photo-crosslinking ; thermal degradation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Radical copolymerization of donor-acceptor monomers, i.e., allylglycidyl ether (AGE), maleic anhydride (MA) and methyl methacrylate (MMA) are studied, where binary copolymerization of AGE...MA complex with MMA is obtained. Constants of charge transfer complex formation (Kc) and copolymerization (r1 and r2) are determined by 1H-NMR and Kelen-Tüdöş methods, respectively. It is found that synthesized film-forming terpolymers with free epoxy and anhydride groups on side chain of macro-molecules are being crosslinked easily under the effect of temperature and/or UV-ir-radiation. Observed crosslinking effect is proved by the DTA, TGA, and IR spectroscopic analyses. It is shown that complex-radical terpolymerization is very convenient method for the designing of reactive functional macromolecules of linear structure with self-crosslinking properties which can serve as a basis for the use in photolithographic applications. © 1995 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/pola.1995.080330905
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    Macromolecular synthesis from saccharic lactones. Polyaddition of D-glucaro- and D-mannaro- 1,4:6, 3-dilactones with diisocyanates and hydrolyzability of the resulting polyurethanes having dilactone rings in the main chains (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1495-1503 
    Details
    ISSN: 0887-624X
    Keywords: saccharic acid ; dilactone ; polyaddition ; polyurethane ; diisocyanate ; deg-radation ; hydrolysis ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polyaddition of saccharic acid dilactones prepared from D-glucose and D-mannitol, D-glu-caro-, and D-mannaro-1,4:6,3-dilactones (1 and 2, respectively), with hexamethylene di-isocyanate (3a) and methyl (S)-2,6-diisocyanatocaproate (3b) was carried out by using dibutyltin dilaurate as a catalyst at 50, 25, and 0°C to give polyurethanes (4 and 5) having dilactone moieties in the main chains. The resulting polymers were found to decompose easily in phosphate buffers under neutral or slightly basic conditions (pH 7 or 8). Therefore, the polyurethanes may be used as novel degradable polymeric materials. © 1995 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1995.080330911
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    Synthesis and polymerization of 1-(2,4,6-tricyanophenylthio)-3-[3,5-bis(n,n-dimethylamino)phenoxy]-2-propyl methacrylate; polymer effect on intramolecular charge-transfer interaction (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1475-1485 
    Details
    ISSN: 0887-624X
    Keywords: methacrylate bearing donor and acceptor moieties ; polymer effect ; intra-molecular charge-transfer interaction ; spacer length ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1-[3,5-Bis(N,N-dimethylamino)phenoxy]-ω-(2,4,6-tricyanophenylthio)alkanes (1a-c), where an electron-accepting 2,4,6-tricyanophenylthio group and an electron-donating 3,5-bis(N,N-dimethylamino)phenoxy one are linked with a spacer such as ethylene, trimethylene, and tetramethylene, were prepared in order to examine an effect of the spacer chain length on intramolecular charge-transfer interaction between the 2,4,6-tricyanophenylthio and 3,5-bis(N,N-dimethylamino)phenoxy groups. From the UV-vis spectra measurements of 1a-c, 1-[3,5-bis(N,N-dimethylamino)phenoxy]-3-(2,4,6-tricyanophenylthio)Propane (1b) carrying the trimethylene chain as a spacer was found to have the strongest intramolecular charge-transfer interaction. A new methacrylate-type monomer carrying the 1b unit as a side chain, 1-(2,4,6-tricyanophenylthio)-3-[3,5-bis(N,N-dimethylamino)phenoxy]-2-propyl methacrylate (2), was prepared successfully in 9.2% total yield in seven steps. The monomer 2 homopolymerized in benzene, tetrahydrofuran, acetone, and dimethyl sulfoxide in the presence of 2,2′-azobis(isobutyronitrile) at 60°C to give polymers [poly(2)] with molecular weights of 6,000 to 98,000. An intramolecular charge-transfer interaction in the poly(2) was found to be larger than that in the monomer 2 and to increase with an increase in the degree of polymerization of the poly(2), suggesting that there is an existence of polymer effect other than the polymer effect due to the high local concentration of the donor-acceptor pair. © 1995 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/pola.1995.080330909
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    Dispersion polymerization in polar solvents (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1511-1521 
    Details
    ISSN: 0887-624X
    Keywords: dispersion polymerization ; micron-size monodisperse polymer particles ; sty-rene ; butyl acrylate ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of the nitrogen purge, monomer purification, type of agitation, and presence of costabilizer on the particle size distribution (PSD) was investigated in the dispersion po-lymerization of styrene in ethanol and in the dispersion copolymerization of styrene and butyl acrylate in a water-ethanol mixture. Purging with nitrogen and, to a lesser extent, monomer purification, were of paramount importance to achieve monodispersity. The type of agitation had a week effect on the PSD, whereas the presence of costabilizer had no effect on the PSD. © 1995 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/pola.1995.080330913
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  • 150
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    Oxidative polymerization of pyrrole in polymer matrix (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1581-1587 
    Details
    ISSN: 0887-624X
    Keywords: matrix polymerization ; polypyrrole ; chemical synthesis ; interpolymer complex ; water soluble polypyrrole ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The oxidative matrix polymerization of pyrrole (Py) by Ce(IV) in the presence of Polyacrylic acid (PAA) has been studied to obtain water-soluble and insoluble products. The role of the PAA, Pyrrole, and Ce(IV) concentration, order of component addition, the structure of polymer matrix (PAA, Hydroxy Ethyl Cellulose (HES), Poly-N-vinylpyrrolidone (PVP)], and model unit of PAA (propionic acid), on the polymerization system were investigated.Interaction of PAA with insoluble polypyrrole (PPy) and the interpolymer complex formation were investigated along with the aggregation of PPy onto the matrix polymer followed by spectral shifts. FTIR results of insoluble products obtained from the PAA-Py-Ce(IV) system and solubility of the system is explained in light of the mechanism of the polymerization of pyrrole on the polymer matrix. © 1995 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/pola.1995.080331004
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  • 151
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    Fully aromatic thermotropic liquid crystalline polyesters of 3-phenyl-4,4′-biphenol with 4,4′-benzophenone dicarboxylic acid (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 415-426 
    Details
    ISSN: 0887-624X
    Keywords: thermotropic ; liquid crystalline polymer ; nematic ; synthesis ; characterization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of fully aromatic, thermotropic polyesters, derived from 3-phenyl-4,4′-biphenol (MPBP), nonlinear 4,4′-benzophenone dicarboxylic acid (4,4′-BDA), and various other comonomers was prepared by the melt polycondensation method and characterized for their thermotropic liquid crystalline behavior by a variety of experimental techniques. The homopolymer of MPBP with 4,4′-BDA had a fusion temperature (Tf) at 240°C, exhibited a nematic liquid crystalline phase, and had a narrow liquid crystalline range of 60°C. All of the copolyesters of MPBP with 4,4′-BDA and either 30 mol % 4-hydroxybenzoic acid (HBA), 6-hydroxy-2-naphthoic acid (HNA) or 50 mol % terephthalic acid (TA), 2,6-naphthale-nedicarboxylic acid (2,6-NDA) and low Tf values in the range of 210-230°C, exhibited a nematic phase, and had accessible isotropization transitions (Ti) in the range of 320-420°C, respectively. As expected, each of them had a broader range of liquid crystalline phase than the homopolymer. They had a “frozen” nematic, glassy order as determined with the wide-angle X-ray diffraction (WAXD) studies. The morphology of each of the “as-made” polyesters had a fibrous structure as determined with the scanning electron microscopy (SEM), which arises because of the liquid crystalline domains. Moreover, they had higher glass transition temperatures (Tg) in the range of 167-190°C than those of other liquid crystalline polyesters, and excellent thermal stabilities (Td) in the range of 500-533°C, respectively. © 1995 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/pola.1995.080330309
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    Radical polymerization of micelle-forming monomers in water (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1727-1733 
    Details
    ISSN: 0887-624X
    Keywords: polymerizing detergents ; monomer micelles ; radical polymerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photo- and thermoinitiated radical polymerization of surface-active monomers with various structures was investigated in solution and in micelles in water. The relationship between kinetics and the structure of monomer associates was represented in the form of a universal curve. A model and kinetic description of polymerization in spherical micelles of monomer was proposed. The problem of micelle fixation by polymerization was solved. © 1995 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1995.080331020
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    Lyotropic liquid crystalline main-chain viologen polymers (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1745-1749 
    Details
    ISSN: 0887-624X
    Keywords: viologen polymer ; lyotropic ; critical concentration ; synthesis ; characterization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: [no Abstrat]
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1995.080331022
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  • 154
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    Compartmentalized polymerization initiated by oil-soluble initiators. Calculation of average number of radicals per particle (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1759-1765 
    Details
    ISSN: 0887-624X
    Keywords: compartmentalized ; seed ; emulsion ; oil-soluble initiators ; average radical number ; radical polymerization ; Kummer functions ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Expressions for calculating the stationary state distribution of radicals in compartmentalized systems with a constant number of reaction loci containing an oil-soluble initiator are given. Besides pairwise formation of radicals in the particles, desorption and reabsorption, water phase termination, solubility of the initiator in the aqueous phase, and the possibility of formation of a single radical species are taken into consideration. The calculation is based on a probabilistic analysis leading to a third-order recurrence relation solved using confluent, hypergeometric Kummer functions. Some calculated curves illustrating the de-pendence of the average number of radicals per particle on various relevant parameters are included. © 1995 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/pola.1995.080331102
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    Photoinitiated cationic polymerization of oxetane formulated with oxirane (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1807-1816 
    Details
    ISSN: 0887-624X
    Keywords: Oxetane ; oxirane ; photoinitiated cationic polymerization ; semiempirical molecular orbital calculation ; real-time FT-IR ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photoinitiated cationic polymerization of oxetane, oxirane (epoxide), and a formulation of both was carried out and their reactivity compared. To investigate a formulated system of oxetane and oxirane in photoinitiated cationic polymerization, computational and experimental methods were used. In the computational study, we employed a semiempirical molecular orbital method (AM1). On the other hand, the reactivities of each system were evaluated and compared experimentally by a real-time FT-IR method. The computational study reveals that oxetane seems to polymerize in SN2 mechanism, but two possibilities, of SN1 mechanism through the α-cleavage and of SN2 mechanism through β-cleavage, are implied for oxirane. Using the real-time FT-IR method, the formulation of oxetane and oxirane was proved to possess rather high reactivities of oxetane toward photoinitiated cationic polymerization. The formulated system exhibited slightly lower number-average molecular weight than oxetane but higher than oxirane. These experimental observations are well explained in terms of the calculated reaction paths. © 1995 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/pola.1995.080331107
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    Emulsion polymerization of supermicron, monodisperse acrylic copolymer particles with core-shell structures (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1849-1857 
    Details
    ISSN: 0887-624X
    Keywords: emulsion polymerization ; acrylic polymers ; core shell ; supermicron ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The emulsion polymerization of large MMA/BA copolymer particles with narrow particle size distributions and core-shell structure is described. A series of sequential seeded growth emulsion polymerizations were used to obtain monodisperse particles with diameters of at least 3 μm, at 30% solids contents. Because the core and shell polymers used here were chemically similar, core-shell structures could not be verified by differential staining tech-niques. Core-shell structure was demonstrated by minimum film-forming temperature studies and by scanning electron microscopy in conjunction with energy dispersive x-ray analysis, using chlorine-labeled core polymers. © 1995 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/pola.1995.080331112
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    Role of polycation promoters in the cobalt(II) phthalocyaninetetracarboxylic and -octacarboxylic acid-catalyzed autoxidation of mercaptoethanol (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1841-1848 
    Details
    ISSN: 0887-624X
    Keywords: 2,4-ionene ; poly(quaternary ammonium)salt ; cobalt(II) phthalocyaninetetra-carboxylic acid ; cobalt(II) phthalocyanineoctacarboxylic acid ; mercaptoethanol ; autoxi-dation ; catalysis ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The promoting effects of 2,4-ionene on the cobalt(II) phthalocyaninetetracarboxylic acid-[CoPc(COOH)4] and cobalt(II) phthalocyanineoctacarboxylic acid-[CoPc(COOH)8] cata-lyzed autoxidation of 2-mercaptoethanol were studied. Dimerization of the CoPc(COOH)4 catalyst, combined with the disappearance of the catalytically inactive μ-peroxo complex and the appearance of substrate enrichment in the presence of 2,4-ionene, results in a 40-fold enhancement of the oxidation rate as compared with the polymer-free system. UV-VIS spectroscopy indicates that CoPc(COOH)8 is incapable of forming μ-peroxo complexes or 2,4-ionene-induced dimeric catalyst species under normal reaction conditions. Thus, it was possible to study exclusively the ionene-induced effect of substrate enrichment. Addition of 2,4-ionene to an aqueous CoPc(COOH)8 solution results in an activity enhancement by a factor of 2-3, which can be ascribed to substrate enrichment. Additionally, using mono-disperse ionene oligomers showed a molecular weight dependence of 2,4-ionene on the catalytic activity of CoPc(COOH)8, as was observed for the conventional 2,4-ionene/cobalt phthalocyaninetetrasodiumsulfonate system. The optimal polycation/catalyst ratios of both systems decrease with increasing chain length of 2,4-ionene, until a constant value is reached. This leads to the conclusion that the optimal polymer/catalyst ratios are predominantly determined by substrate enrichment. © 1995 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/pola.1995.080331111
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    Simultaneous polymerization and formation of polyphenylacetylene film by Nd(P204)3-Fe (AA)3-Al(i-Bu)3 combined catalyst system (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1873-1879 
    Details
    ISSN: 0887-624X
    Keywords: combined catalyst system ; polymerization ; polyphenylacetylene film ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The simultaneous polymerization and formation of polyphenylacetylene film by Nd(P204)3-Fe(AA)3-Al(i-Bu)3 catalyst system have been investigated. The combined catalytic effects between rare earth phosphonates with MT(naph)x or Fe(AA)3 systems are first proposed and compared. The polymerization features and kinetic behaviors with Nd(P204)3-Fe(AA)3-Al(i-Bu)3 system are described and discussed. The combined catalytic effects have the following order, respectively: Fe ≫ Co 〉 Cr 〉 Mn-Ni, Nd(P204)3-Nd(P507)3 〉 Nd(P350)3 and Tb 〉 Sm 〉 Yb 〉 Ho 〉 Lu 〉 Dy 〉 Nd-Er-Pr 〉 Y-Tm 〉 Ce 〉 Gd 〉 La. The overall polymerization activation energy was found to be 20.8 kJ/mol showing coordination-anionic polymerization characteristic. PPA films so obtained are very similar to the rare earth ones. © 1995 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/pola.1995.080331115
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    Polymerization of [o-n-(perfluorohexyl)phenyl]acetylene and polymer properties (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1907-1912 
    Details
    ISSN: 0887-624X
    Keywords: substituted polyacetylene ; fluorine-containing polymer ; transition-metal catalyst ; gas permeability ; pervaporation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis, properties, and membrane-separation functions of a novel fluorine-containing poly(phenylacetylene) were examined. The monomer used was [o-n-(perfluorohexyl)phe-nyl]acetylene, which has a rigid rod-like ortho-substituent. Polymers, whose intrinsic vis-cosities ([η]) were ca. 0.4-2.2 dL/g, were obtained in high yields with various W and Mo catalysts. The MoCl5-Ph3Sb catalyst achieved the highest [η] of 2.25 dL/g corresponding to an Mw over one million. The polymer was a brown solid soluble only in F -containing solvents such as m-(CF3)2C6H4. The oxygen permeability coefficient of the polymer mem-brane was 90 barrers, which is the second highest among those of ortho-substituted poly(phenylacetylenes). In the pervaporation of an ethanol-water mixture, the poly-mer membrane showed ethanol permselectivity [α(EtOH/H2O) = 1.7]. © 1995 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/pola.1995.080331119
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    Synthesis of aldehyde-telechelic poly(vinyl ether)s by the reaction of bifunctional living cationic polymers with water (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1921-1925 
    Details
    ISSN: 0887-624X
    Keywords: telechelic polymers ; living polymerization ; cationic polymerization ; vinyl ether ; aldehyde ; water ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1995.080331122
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  • 161
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    Hybrid inorganic/organic interpenetrating polymer networks based on zeolite 13x and polystyrene (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1979-1985 
    Details
    ISSN: 0887-624X
    Keywords: IPN ; zeolite ; polystyrene ; solid-state ; 13C-NMR ; SEM ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A hybrid inorganic/organic interpenetrating polymer network (IPN) of a three-dimensional network structure zeolite crystal (13X, powder) and crosslinked or linear polystyrene (PS) was prepared and characterized by differential scanning calorimetry (DSC), solid-state13C-NMR, and scanning electron microscopy (SEM). The size and shape of the crystalline zeolite particles were revealed on SEM micrographs in both the pure zeolite and the IPNs. Solubility tests and the results of DSC with solid-state 13C-NMR confirm that some organic PS chains are incorporated within the internal three-dimensional channels of the zeolite particles. We speculate that the internal PS chains may adopt an extended “one-dimensional” conformation and exhibit no bulk polymer glass transition. These novel hybrid inorganic/organic IPNs are a new kind of IPN structure. © 1995 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/pola.1995.080331204
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    Main chain scission reaction of poly(methyl methacrylate) caused by two-photon ionization of dopant (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1969-1978 
    Details
    ISSN: 0887-624X
    Keywords: poly(methyl methacrylate) ; TMPD ; two-photon ionization ; main chain scission ; ESR ; GPC ; radical anion ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The main chain scission reaction of poly(methyl methacrylate) (PMMA) doped with N,N,N,′,N′-tetramethyl-p-phenylenediamine (TMPD) was examined by ESR spectroscopy and GPC measurement, and the scission mechanism was analyzed. The two-photon ionization of TMPD with excimer laser excitation at 77 K produced an ester radical anion of PMMA (PMMA·m̌), which becomes the main chain tertiary radical —CH2—C·(CH3)—CH2—after the detachment of the ester side group by annealing of the sample at room temperature. The main chain scission radical ·C(CH3)(COOCH3)—(PMMA·) which was produced by the β-scission from—CH2—·C(CH3)—CH2—showed the 13-line ESR spectrum instead of the ordinary 9-line, due to the fast quenching of the sample to 77 K. The change of the molecular weight distribution was measured by GPC after several irradiation-and-annealing operations. The simulation of the GPC curve confirmed that the scission re-action occurs at random in the PMMA chain in the solid and the main chain scission yield from the ester radical anion, [PMMA·]/[PMMA·m̌], is 0.30. © 1995 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/pola.1995.080331203
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    Surface modification of aromatic polyamide film by oxygen plasma (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2001-2011 
    Details
    ISSN: 0887-624X
    Keywords: surface modification ; aromatic polyamides ; oxygen plasma ; bond scission ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The surface of poly(p-phenylene terephthalamide) (PPTA) films was modified by oxygen plasma, and the modified film surface was analyzed by an advancing contact meter and X-ray photoelectron spectroscopy (XPS). The advancing contact measurement showed that the oxygen plasma treatment made the surface of the PPTA film hydrophilic. The XPS analyses also showed the increase in the O/C and N/C atom ratio, especially the O/C atom ratio, at the PPTA film surface by the oxygen plasma treatment. A main oxygen functionality formed by the oxygen plasma treatment is a carboxylic acid group, and a main nitrogen functionality formed is a protonated amino group. The formation of the oxygen and nitrogen functionalities formed by the oxygen plasma treatment is not restricted to the surface of the PPTA film, but penetrates at least 35 Å deep from the film surface. The formation of these carboxylic acid and protonated amino groups is a result of the bond scission of the amide linkages in the PPTA film. Interactions of photons in the oxygen plasma rather than interactions of electrons and activated oxygen atoms contribute greatly to the bond scission. © 1995 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/pola.1995.080331207
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    Vacuum-ultraviolet induced oxidation of the polymers polyethylene and polypropylene (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2013-2025 
    Details
    ISSN: 0887-624X
    Keywords: vacuum ultraviolet oxidation ; polyethylene ; polypropylene ; plasma-polymer interaction ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The emission from low-pressure microwave plasmas in the vacuum-ultraviolet (VUV) region (λ 〈 200 nm) was investigated in order to use these plasmas as light sources for the study of the VUV photochemistry of polyethylene (PE) and polypropylene (PP) as part of the study of plasma-polymer interaction. These polymers, immersed in low-presure oxygen, were exposed to radiation with wavelengths down to 112 nm, the cut off of magnesium fluoride used as a window to separate the polymer specimen from the plasma light source. Total oxygen incorporation in the surface [O], and the formation of hydroxyl, carbonyl, and carboxyl groups were measured using XPS in combination with chemical derivatizations, particularly their dependence upon the radiation spectrum and the oxygen pressure around the sample. In most experiments the surface oxygen concentration [O] attained a constant value that appears to be related to the initial oxidation rate; this suggests a competition between oxygen incorporation and chain scission reactions, followed by the removal of volatile oxidation products. PE is usually oxidized to a higher level than PP, the latter appearing to be more susceptible to reaction with atomic oxygen than PE. A general initiation mechanism for the VUV experiments is proposed that allows us to explain the observed differences in behavior between PE and PP, and the results obtained under different irradiation conditions. The nature of oxidation products is in both cases very similar to what is observed after direct plasma treatment of the polymers. We conclude that short wavelength radiation contributes very appreciably to the observed surface modification effects during plasma treatment of PE and PP. © 1995 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
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    Synthesis and kinetics of polymerization of unsaturated monomers with OH groups in their structure. II. 3-hydroxyneopentyl methacrylate (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2057-2067 
    Details
    ISSN: 0887-624X
    Keywords: methacrylate monomers ; polymerization kinetics ; stereostructure ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of unsaturated monomers containing one or more hydroxyl groups by reaction between polyalcohols (number of OH, n≥2) and monoacid chlorides has been theoretically analyzed. The difficulties were shown involved in the preparation of these monomers with a high degree of purity even in the most favorable case of the completely substituted compound. The calculated mole fractions of the two monomers that can be obtained by reaction between neopentylglycol and methacryloyl chloride were compared with the experimental ones. Kinetic experiments of the polymerization of 3-hydroxyneopentyl methacrylate and 2-hydroxyethyl methacrylate were carried out at different temperatures in 1,4-dioxane for the former monomer and dioxane and absolute ethanol for the latter. Dilatometric techniques and nonlinear least-squares methods were used to obtain kinetic data and to determine the kinetic constants, respectively. In homogeneous solution the values of kp/k1/2t for the 3-hydroxyneopentyl methacrylate and 2-hydroxyethyl methacrylate was determined by 13C-NMR spectroscopy and the molar fractions of tactic triads and dyads were calculated from different resonance signals. The polymers are predominantly syndiotactic and follow a Bernoullian distribution of tactic sequences. Finally, the glass transition temperatures of both polymers, determined calorimetrically, were 145 and 89°C, respectively. © 1995 John Wiley & Sons, Inc.
    Additional Material: 12 Ill.
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    Rapid communications: Synthesis and characterization of random poly(amide-imide-sulfonamide)s. I. Polymers derived from unsymmetrical diamine monomers (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1917-1920 
    Details
    ISSN: 0887-624X
    Keywords: poly(amide-imide-sulfonamide)s ; unsymmetrical diamino monomers ; Yamazaki reaction ; triphenylphosphite ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/pola.1995.080331121
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    Monocarbamate diols: Synthesis and polymerization (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1935-1940 
    Details
    ISSN: 0887-624X
    Keywords: solketal ; monocarbamate diol ; polyurethane ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/pola.1995.080331124
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    Book review (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1941-1942 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1995.080331125
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    Tandem GC/MS: A useful tool for studying end-capping reactions of oligo(styryl)lithium anions (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1957-1967 
    Details
    ISSN: 0887-624X
    Keywords: end-capping reactions ; oligo(styryl)lithium anions ; gas chromatography ; mass spectrometry ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Anionic living polymerization methods, using organometallic initiators such as butyllithium reagents, have proven useful for, inter alia, styrene polymerization and are amenable to subsequent functionalization of poly(styryl)lithium in the termination step. In this study, general methods for the selective preparation of small styrene oligomers and termination of the intermediate oligo(styryl)lithium anions were investigated. The crude reaction mixtures were analyzed directly by tandem gas chromatography/mass spectrometry (GC/MS). Of the carbon- and silicon-based electrophiles tested, chloro(chloroalkyl)silanes, Cl-SiR2(CH2)nCl in particular, were shown by GC/MS to be regioselective end-capping reagents, thus allowing subsequent transformation to the primary amine. The combined GC/MS data allow not only an estimate of the degree of functionalization, but also the identification of by-products, thus providing insight into the end-capping process that otherwise might be difficult to access. © 1995 John Wiley & Sons, Inc.
    Additional Material: 5 Tab.
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    Synthesis and properties of aromatic polyamides with oligobenzamide pendent groups. I. Poly-5-(4-benzoylamino-1-benzoylamino)isophthalamides (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1987-1994 
    Details
    ISSN: 0887-624X
    Keywords: aromatic polyamides ; polyisophthalalamides ; pendent oligomeric benzamide groups ; 5-(4-benzoylamino-1-benzoylamino)isophthalic acid ; water uptake ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of polyisophthalamides having pendent oligomeric benzamide groups were prepared by the Yamazaki reaction from common aromatic diamines and 5-(4-benzoylamino-1-benzoylamino)isophthalic acid. The latter was synthesized from 5-aminoisophthalic acid in a three-step synthesis by successive incorporation of benzamido groups. The new polymers were characterized by NMR, DSC, TGA, and WAXD and the properties were compared to those of corresponding unsubstituted polyisophthalamides. All of the polymers were essentially amorphous and their Tgs were about 20°C higher than the reference polymers. Initial thermal decomposition temperatures ranged from 375 to 420°C. All of the polymers were soluble in aprotic polar solvents without added salts. Properties of particular note were: the water uptake, which was particularly high, ranging from 7.5 to 18.2%, and the temporary insolubilization in concentrated sulfuric acid of films of the polymers heated for a short time to ≥ 200°C. © 1995 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/pola.1995.080331205
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    Graft polymerization of acrylamide onto LLDPE film by electron beam pre-irradiation in air and argon. II. Influence of mohr's salt (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2049-2055 
    Details
    ISSN: 0887-624X
    Keywords: graft polymerization ; grafting rate ; electron beam irradiation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: LLDPE film pre-irradiated by electron beam (EB) in air and argon was grafted in an aqueous acrylamide solution containing Mohr's salt in the concentration range 0.0025-2% The grafting rate and yield were strongly dependent on the Mohr's salt concentration, mainly as a result of chain termination. The exponential grafting rate dependence on the pre-irradiation dose was quite insensitive to a hundred-fold variation in Mohr's salt concentration. © 1995 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/pola.1995.080331212
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    Synthesis of aromatic polyesters having pendant carboxyl groups in the side chains and conversion of the carboxyl groups to other reactive groups (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2157-2163 
    Details
    ISSN: 0887-624X
    Keywords: reactive polyester ; pendant carboxyl group ; chemoselective polycondensation ; polymer catalyst ; polymer reaction ; bifunctional catalytic mechanism ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aromatic polyester, copolyester, and poly(ester-amide-thioester) having pendant carboxyl groups are directly synthesized by the organic phase/water phase interfacial polyconden-sation using low-molecular and polymeric phase transfer catalysts. Spectral analysis of the resulting polymers indicates that the nucleophilicity of salts of phenols to diacid chloride is far higher than that of salts of carboxylic acids and chemoselective esterification occurs in a 100% yield. Even if the polymeric catalyst having amino acid moiety as a nucleophilic group is used in the polycondensation, the polymers do not contain anhydride groups. The polyester can be almost quantitatively converted to polymers with different reactive groups by reacting the pendant carboxyl groups with alkyl halides in a DMAc-H2O mixture con-taining K2CO3. A bifunctional catalytic mechanism is proposed for the chemical modification of the polyesters. © 1995 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/pola.1995.080331309
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    Copolymerization of butadiene and styrene with a gadolinium tricarboxylate catalyst (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2175-2182 
    Details
    ISSN: 0887-624X
    Keywords: gadolinium tricarboxylate ; copolymerization of butadiene and styrene ; effect of pKa of ligand ; diad analysis ; cis polymerization mechanism ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Homo- and copolymerizations of butadiene (BD) and styrene (St) were carried out by gadolinium catalysts having various tricarboxylate ligands [Gd(OCOR)3: R = CH3, CH2Cl, CHCl2, CCl3, and CF3], to investigate the effects of ligands and discuss the cis polymerization mechanism. Polymerization of BD with Gd(OCOR)3 - (i - Bu)3Al - Et2AlCl catalysts was carried out in hexane at 50°C. By each catalyst, poly(BD) having a high cis content (cis = 97-99%) in 22-85% yields for 2-24 h were obtained. The ligands with low pKa values increased the polymerization activity as follows: R of Gd(OCOR)3: CF3 〉 CCl3 〉 CHCl2 〉 CH2Cl ∼ CH3. On the other hand, in the polymerization of St or copolymerization of BD and St under similar conditions, the highest activity was attained by a Gd(OCOCCI3)3- based catalyst. The difference in the optimum ligand among the homo- and copolymerization of BD and St was discussed on the basis of energy levels of the catalysts. In the copolymers of BD and St, the cis-1,4 content of the BD unit decreased with increasing St content. Furthermore, according to the diad analysis of copolymers (St content ∼ 14.5 mol %) by 13C NMR spectroscopy, the low cis value of the BD unit was observed in the St-BD diad (cis/trans/vinyl = 24/53/23), while the high cis value of the BD unit remained in the BD-BD diad (cis/trans/vinyl = 89/10/1). These results suggest that the terminal BD unit is controlled by the cis configuration by the coordination between the penultimate cis vinylene unit and the gadolinium metal catalyst, whereas the presence of the penultimate St unit interferes with cis polymerization of the terminal BD unit. The difference in the coordination mechanism in the course of polymerization between rare earth metal and transition metal catalysts such as the Ni(acac)2 and Co(acac)3-based catalyst was also discussed. © 1995 John Wiley & Sons, Inc.
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    Polymers of carbonic acid. XIV. High molecular weight poly(trimethylene carbonate) by ring-opening polymerization with butyltin chlorides as initiators (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2193-2201 
    Details
    ISSN: 0887-624X
    Keywords: ring-opening polymerization ; poly(trimethylene carbonate) ; butyltin tri-chloride ; cationic mechanism ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Numerous BuSnCl-3, Bu2SnCl-2, and Bu3SnCl-initiated polymerizations of cyclo(tri-methylene carbonate) (TMC) were conducted in bulk. In addition to the initiator, reaction time, temperature, and monomer/initiator (M/I) ratio were varied. Yields above 90% were obtained with all three initiators, but their reactivities decrease in the order BuSnCl3 〉 Bu2SnCl2 〉 Bu3SnCl. The maximum molecular weights decrease in the same order. With BuSnCl3 Mws up to 250,000 were obtained. These molecular weights were determined by GPC on the basis of the universal calibration method. In this connection Mark-Houwink equations for two solvents, tetrahydrofuran (THF) and CH2Cl2 were determined and compared with literature data. Furthermore, mechanistic aspects were studied. 1H- and 13C- NMR spectra revealed that BuSnCl3 forms complexes with the CO-group of TMC, whereas Bu2SnCl3 do not cause NMR spectroscopic effects. Kinetic studies in chloroform and nitrobenzene and a comparison with Bu3SnOMe suggest that at least BuSnCl3 initiates a cationic mechanism. However, in contrast to SnCl4 (or SnBr4), BuSnCl3 does not cause decarboxylation. Regardless of the initiator 1H-NMR spectroscopy revealed CH2OH and CH2CI endgroups in all cases. © 1995 John Wiley & Sons, Inc.
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  • 175
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    LC polyimides. XXI. Thermotropic poly(amide-imide)s based on trimellitimides (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2241-2250 
    Details
    ISSN: 0887-624X
    Keywords: poly(amide-imide)s ; trimellitic acid ; smectic-A phase ; phase transition ; synchrotron radiation ; bâttonet texture ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polycondensation of α, ω-bis(-4-aminophenoxy) alkanes with trimellitic anhydride chloride (TMA-Cl) in m-cresol yielded a new class of poly(amideimide)s. Starting from the same diamine spacers poly(amideimides) with a more regular sequence of amide and imide groups were prepared by another synthetic method. All these poly(amide-imide)s are semi-crystalline and melt in the range of 250-300°C. They form a smectic-A phase over a narrow temperature range and suffer thermal degradation at the isotropization temperature (330-350°C). The smectic-A phase was characterized by optical microscopy (“batonnet texture”) and by synchrotron radiation measurements conducted at a heating rate of 20°C. Furthermore, it is demonstrated that slight variation of the chemical structure, such as methyl substituents or meta positions in the spacer prevent the formation of a LC phase. © 1995 John Wiley & Sons, Inc.
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    Cyanate esters based on cardanol modified-phenol-formaldehyde resins: Syntheses and thermal characteristics (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 621-627 
    Details
    ISSN: 0887-624X
    Keywords: phenolic-triazine ; cyanate ester ; phenol formaldehyde resin ; cardanol ; cyclotrimerization ; matrix resin ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cardanol incorporated-phenol-formaldehyde novolac resins were synthesized by acid and base catalyzed reactions. The novolacs were transformed to their cyanate esters. The thermal cure characteristics of the cyanate esters depended upon the composition. The presence of cardanol proportionately facilitated the curing. The thermal characterization of the novolacs and the corresponding cured phenolic-triazine networks indicated a dedicated a detremental effect of cardanol on the thermal stability and char residue of the resins. © 1995 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/pola.1995.080330403
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    Kinetics and mechanism of the grafting of 2-(dimethylamino)ethyl methacrylate onto hydrocarbon substrates (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 633-642 
    Details
    ISSN: 0887-624X
    Keywords: free radicals ; grafting ; kinetics ; methacrylate ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of grafting a basic monomer, 2-(dimethylamino)-ethyl methacrylate (DMAEMA) to hydrocarbon substrates have been investigated. These systems were chosen as models for the grafting of a homopolymerizable monomer to polyolefins such as polyethylene. The reactions with squalane and n-eicosane were initiated by an organic peroxide, 2,5-dimethyl 2,5 dit-butylperoxy)-3-hexyne; grafting yields become significant at high reaction temperatures and low monomer concentrations. In squalane, the order of reaction with respect to monomer increased from about 1.1 for 0.22-0.44M DMAEMA to almost 2 at 0.69M DMAEMA; the order with respect to initiator was 0.56. The overall activation energy in the 130-160°C temperature range was, however, surprisingly low, 42±5 kJ mol-1. When analytical data were used to separate the overall rate into those for grafting and homopolymerization, different kinetic paths were observed for the competing reactions. These results are interpreted in terms of two different mechanisms; intramolecular chain transfer plays an important role in grafting, while depropagation becomes a major factor in homopolymerization at temperatures above 150°C. © 1995 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/pola.1995.080330405
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  • 178
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    Synthesis and photopolymerization of monomers bearing isopropenylphenoxy groups (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 653-663 
    Details
    ISSN: 0887-624X
    Keywords: photopolymerization ; poly(indanes) ; cationic polymerization ; photopolymerizable poly(imide)s ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of a series of monomers containing isopropenylphenoxy groups was carried out. On irradiation with UV light in the presence of onium salt photoacid generators, these monomers undergo a chain extension reaction consisting of a dimerization followed by a Friedel-Crafts ring closure which results in the formation of polymers with indane groups in the backbone. Aryl imide-containing monomers bearing isopropenylphenoxy groups were also shown to undergo facile photoinduced cationic polymerization. The resulting polymers displayed excellent thermal stability. © 1995 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/pola.1995.080330407
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    Effect of aggregation of p-phenylphenol on enzymatic polymer synthesis in dioxane/water mixture (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2339-2345 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The state of p-phenylphenol molecules in dioxane/water mixture, a commonly used reaction system for enzymatic polymerization of phenols and aromatic amines, was investigated by difference UV absorption spectroscopy and Fourier transform (FT) Raman spectroscopy. The aggregate of p-phenylphenols is found on the basis of the exciton peaks observed in difference UV absorption spectra. FT Raman spectroscopy demonstrates further that p-phenylphenol molecules aggregate together in “face to face” fashion. A simplified model is proposed for aggregation of p-phenylphenol molecules in dioxane/water mixture, which can elucidate the variation of the molecular weight of poly (p-phenylphenol) coupled in the reaction system. © 1995 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/pola.1995.080331406
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    Synthesis of new ethynylene-containing aromatic polyamides by palladium-catalyzed polycondensation of aromatic diiodides with aromatic diethynyl compounds having amide units (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2385-2391 
    Details
    ISSN: 0887-624X
    Keywords: soluble ethynylene-containing polyamides ; palladium-catalyzed polyconden-sation ; ethynylene-bearing amide monomers ; thermal behavior ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New ethynylene-containing aromatic polymides were synthesized by the carbon-carbon crosscoupling polycondensation of aromatic diiodides with aromatic amide-bearing diethynyl compounds in the presence of a palladium catalyst, cuprous iodide, and an organic base. The polymers having sulfone linkages were soluble in various organic solvents and their weight average molecular weights were in the range of 12,500 and 26,500. The polymers with the highest inherent viscosity were obtained, when the monomer ratio of a diethynyl compound to a diiodide was 1.01. The polymers showed no detectable glass transition temperature and no weight loss up to around 300° C in nitrogen. The thermal crosslinking of the polymers occurred at 280°C through the existing internal ethynylene group. © 1995 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
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    Propylene polymerization through supported metallocene/ MAO catalysts: Kinetic analysis and modellingDedicated to Professor Dr. J. Klein on the occasion of his 60th birthday (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2393-2402 
    Details
    ISSN: 0887-624X
    Keywords: metallocene, supported ; polypropylene, isotatic ; propylene polymerization, kinetics of, modelling of ; polyolefins, particle growth model for ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several propylene polymerizations are carried out with supported metallocene catalyst, prepared by reaction of silica gel with methylaluminoxane and then with rac-dimethylsi-lanediylbis(indenyl)zirconiumdichloride. The rate-time curves obtained are analyzed to understand the influence of support and triisobutylaluminium on the reaction. As a first attempt to model this system we developed a partially new praticle growth model, based on a shell by shell fragmentation hypothesis (gradual break-up from the outside to the inside of the particle), and a final multigrain structure of the particle. A kinetic scheme including the TIBA interaction with the supported catalyst is also presented. The model prediction and the experimental data are compared for the rate-time curves and polymer properties. © 1995 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
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    Molecular engineering of liquid crystalline polymers by “living” polymerization. XXXII.Part XXXI in this series: Ref. 14; the definition of “living” is presented in Ref. 19d Synthesis and “living” cationic polymerization of 3-fluoro-4′-(ω-vinyloxyalkoxy)-4-biphenylyl (2r,3s)-2-fluoro-3-methylpentanoate with undecanyl and octyl alkyl groups (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2359-2374 
    Details
    ISSN: 0887-624X
    Keywords: 3-fluoro-4′-(11-vinyloxyalkoxy)-4-biphenyl (2R,3S)-2-fluoro-3-methylpen-tanoate ; “living” cationic polymerization ; liquid crystallinity ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis and “living” cationic polymerization of 3-fluoro-4′-(11-vinyloxyundecany-loxy)-4-biphenylyl (2R,3S)-2-fluoro-3-methylpentanoate (12-11) and 3-fluoro-4′-(8-vi-nyloxyoctyloxy)-4-biphenylyl (2R,3S)-2-fluoro-3-methylpentanoate (12-8) are presented. Poly (12-11)s and poly (12-8)s with degrees of polymerization from 4.0 to 16.5 and poly-dispersities ≤ 1.13 have been synthesized and characterized by differential scanning cal-orimetry (DSC) and thermal optical polarized microscopy. Over the entire range of molecular weights poly (12-11)s and poly (12-8)s exhibit an enantiotropic SA and an unidentified SX phase. In addition, regardless of its molecular weight, poly (12-8) exhibits a S*c phase in between the SA and Sx phases. Poly (12-11) and poly (12-8) show lower transition tem-peratures and broader temperature ranges of all their mesophases as compared to the corresponding polymers without a fluorine atom on the biphenyl group. The role of the connecting group between the biphenyl and chiral group of the mesogenic unit on the phase behavior of these polymers is also discussed. Copolymers of 12-8 with (2R,3S)-2-fluoro-3-methylpentyl 4′-(11-vinyloxyundecanyloxy)biphenyl-4-carboxylate (13-11) {i.e., poly-[(12-8)-co-(13-11)] (X/Y), where X/Y represents the molar ratio of monomer 12-8 to monomer 13-11} with DP of ca. 11 and polydispersities lower than 1.23 were also syn-thesized and characterized. Their SA and S*c mesophases exhibit continuous dependences of composition and this support the assignment of the mesophases exhibited by poly (12-8). © 1995 John Wiley & Sons, Inc.
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    Chemoselective hydrosilations. I. Synthesis and photopolymerization of 1-propenyl ether functionalized siloxanes (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2415-2423 
    Details
    ISSN: 0887-624X
    Keywords: photoinitiated cationic polymerization ; 1-propenyl ethers ; siloxanes ; 1-pro-penyl ether-functionalized siloxanes ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of 1-propenyl ether-functionalized siloxanes (PFS) has been achieved by the controlled, rhodium-catalyzed, chemoselective hydrosilation of 1-allyloxy-4(1-propen-oxy) butane with various H-functional siloxanes. It was shown that the hydrosilation pro-ceeds exclusively at the allyl ether group of 1-allyloxy-4(1-propenoxy) butane without par-ticipation at the 1-propenyl ether group. The photoinduced cationic polymerization of these monomers was studied using various analytical techniques and found to take place very rapidly. © 1995 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
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    Spectral and thermal characterization of polyaniline-oxalic acid salt (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2443-2447 
    Details
    ISSN: 0887-624X
    Keywords: polyaniline ; oxalic acid dopant ; EPR ; IR ; UV/V ; TGA ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polyaniline-oxalic acid salts were prepared at 5 and 30°C by chemical polymerization of aniline using different concentration of oxalic acid. Polyaniline base was obtained from the corresponding polyaniline salt by dedoping using aqueous ammonium hydroxide solution. Conductivity measurements, elemental analysis, Infrared, electronic absorption, electron paramagnetic resonance spectral, and thermogravimetric analysis were performed on the polyaniline salts and bases. Composition and the extent of dopant in polyaniline salt systems where determined. The value of composition of polyaniline: oxalic acid is 4: 1.6 and the polymer yield is around 66%. The value of conductivity, polymer yield and composition of polyaniline-oxalic acid salt is independent of concentration of oxalic acid used and also the synthesis temperature. The results are compared with polyaniline-hydrochloride salt prepared by chemical polymerization. The conductivity of polyaniline-oxalic acid salt is three orders of magnitude lower than that of polyaniline-hydrocholoride salt. © 1995 John Wiley & Sons, Inc.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/pola.1995.080331417
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  • 185
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    Electrochemical and structural studies on soluble and conducting polymer from o-phenylenediamine (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2435-2441 
    Details
    ISSN: 0887-624X
    Keywords: poly(o-phenylenediamine) ; solubility ; conducting polymer ; molecular structure ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A conducting polymer, poly(o-phenylenediamine) (PoPD), has been obtained as stable film onto an electrode surface by the electropolymerization of o-phenylenediamine in 0.1 mol dm-3 H2SO4. The film thickness did not exceed 0.85 μm because of its low electrical con-ductivity. The virgin “doped” polymer film was soluble in dimethylsulfoxide N, N-dimeth-ylformamide, acetone, and tetrahydrofuran without any pretreatment. The highest solubility obtained was 17 g dm-3 in dimethylsufoxide. A cast film of PoPD on a substrate was prepared from its dimethylsulfoxide solution. The mean molecular weight of PoPD was found to be 11,000 with the gel permeation chromatography. The STM observation exhibited that the cast film was considerably uniform compared to the electrodeposited film. The cyclic voltammogram of such film showed a reversible redox property accompanied with excellent electrochromism between transparent yellow and brown. It was suggested from the 1H-FTNMR and FTIR spectra and the elemental analysis that the polymeric backbone has 1, 4-substituted benezenoid-quinoid structure. © 1995 John Wiley & Sons, Inc.
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    The synthesis and study of the photoinitiated cationic polymerization of novel cycloaliphatic epoxides (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2463-2471 
    Details
    ISSN: 0887-624X
    Keywords: cycloaliphatic epoxides ; mechanistic studies ; photoinitiated cationic poly-merization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of a series of difunctional epoxides bearing two epoxycyclohexyl groups linked together by an alkylene ether group has been carried out. Subsequently, the reactivities of these novel monomers was investigated and compared to the reactivity of the cycloali-phatic epoxide, 3,4-epoxycyclohexylmethyl 3′,4′-epoxycyclohexane carboxylate (I) in pho-toinitiated cationic polymerization. It was observed that alkylene oxide linking the two epoxycyclohexyl groups was short and the monomers are more reactive than I. The effects of the photoinitiator structure and the experimental conditions of the cationic photopo-lymerization on the rates was also studied using real-time infrared spectroscopy. © 1995 John Wiley & Sons, Inc.
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    Synthesis of 1-(vinylbenzyl)thymine, a novel, versatile multi-functional monomer (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2515-2519 
    Details
    ISSN: 0887-624X
    Keywords: thymine styrene monomer ; functional styrene monomer ; multifunctional monomer ; photoresist ; photocrosslinking ; photopolymer ; 2π + 2π photocyclization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/pola.1995.080331425
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    A Nd-carboxylate catalyst for the polymerization of 1,3-butadiene: The effect of alkylaluminums and alkylaluminum chlorides (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2505-2513 
    Details
    ISSN: 0887-624X
    Keywords: neodymium ; polybutadiene ; alkylaluminum ; alkylaluminum chloride ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The ternary neodymium-based catalyst for the polymerization of 1,3-butadiene, Nd(versatate)3/Ali-Bu2H/tert-butyl chloride, has been examined with respect to the effects of a range of alkylaluminums and alkylaluminum chlorides. Using either pre-formed or in situ catalysts, observations pertaining to catalyst activity and physical state and the characteristics of the final polymer are discussed. The catalyst activity series with the type of alkylaluminum was found to be: Aln-Pr3 ≫ Aln-Dodec3 = Aln-Oct3 = Aln-Hex3 〉 Ali-Bu2H 〉 Ali-Bu3 〉 AlEt3 ≫ AIMe3. Polybutadiene cis content was found to vary with the type of alkylaluminum used. Pre-formed catalysts using methylaluminum chlorides as chloride source were found to be the most active; AlMe2Cl chloride gave the highest activity. The activity of in situ catalysts prepared using alkylaluminum chlorides was found to be independent of alkylaluminum chloride structure. Polybutadiene prepared using catalysts based on different alkylaluminums and alkylaluminum chlorides was found to decrease in cis content with conversion. © 1995 John Wiley & Sons, Inc.
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    Radiation-Induced sol-gel transition of protein: Effects of radiation and metal ions on viscosity property (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2521-2522 
    Details
    ISSN: 0887-624X
    Keywords: gelatin ; sol-gel transition ; metal ions ; viscosity ; radiation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1995.080331426
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    Fundamental studies of grafting reactions in free radical copolymerization. I. A detailed kinetic model for solution polymerization (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2533-2549 
    Details
    ISSN: 0887-624X
    Keywords: free radical ; grafting ; kinetics ; model ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Graft site initiation occurs by primary radical and/ or polymeric radical attack on the back-bone polymer. The controlling mechanism is determined by the structure of the backbone and the activity of the free radicals. The efficiency of incorporating monomer into the graft chains depends upon the graft site initiation mechanism and the mode of polymer chain termination (recombination or disproportionation). A kinetic analysis results a series of uniquely different expressions describing the graft efficiency, φ corresponding to different combinations of graft site initiation and chain termination mechanisms. The dependency of φ upon monomer, initiator, and backbone concentrations is different from case to case. The complete kinetic model is capable of predicting reaction rate, graft efficiency, graft frequency, graft ratio, and molecular weight averages and distributions. Simulations are provided to compare predicted results with experimental data for two different systems which show contrasting mechanisms of graft site initiation and mode of termination. © 1995 John Wiley & Sons, Inc.
    Additional Material: 14 Ill.
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    The conformation and dynamics study of amphoteric copolymers, P(sodium 2-methacryloyloxyethanesulfonate-co-2-methacryloyloxyethyltrimethylammonium iodide), using viscometry, 14N-, and 23Na-NMR (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2613-2621 
    Details
    ISSN: 0887-624X
    Keywords: solution conformation ; amphoteric copolymer ; 14N-NMR ; 23 Na-NMR ; poly-electrolyte ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Solution conformations and dynamic mobilities of novel amphoteric copolymers were studied for aqueous solutions of p(sodium 2-methacryloxyethanesulfonate-co-2-methacryloy-loxyethyltrimethylammonium iodide) [P(NaMES-co-METMAI)] as a function of com-position, concentration, and addition of HCI or KCI. As HCI or KCI was added successively to 5 w/v% copolymer solutions, the reduced viscosities of the solutions were reduced except the 1:1 copolymer solution. The dynamic mobility of the cationic side chain was estimated with the quadrupolar 14N-NMR relaxation technique. The motion of the interacting coun-terion, Na+, was studied by Poisson-Boltzmann electrostatic theories and the quadrupolar 23Na-NMR. Since the intramolecular 1:1 ion pair between MES- and METMA+ acts as an effective charge-screening factor, the copolymers P(NaMES-co-METMAI) behave as ordinary polyelectrolytes with the exception of the 1 : 1 copolymer. © 1995 John Wiley & Sons, Inc.
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    URL: http://dx.doi.org/10.1002/pola.1995.080331507
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  • 192
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    The association of aqueous phenolic resin with polyethylene oxide and poly(acrylamide-co-ethylene glycol) (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2605-2612 
    Details
    ISSN: 0887-624X
    Keywords: complex formation ; PEO ; copolymer ; phenolic resin ; hydrogen bonding ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Comb copolymers formed from acrylamide and poly(ethylene-glycol) methacrylate macro-monomer (PAM-co-PEG) were compared to poly(ethylene oxide) (PEO) with respect to hydrogen bond complex formation with water-borne phenolic resins. The behaviors of the two types of high molecular weight polyethers were similar. Complex formation gave a transient increase in viscosity followed by precipitation. Copolymers with pendant PEG chain lengths ≥ 9 formed complexes with phenolic resin whereas PEG homopolymer with a molecular weight of 2000 did not form a complex. For both copolymer and high molecular weight PEO, the tendency of the complex to precipitate increased when the pH was decreased from 7 to 4. Acridine orange, a cationic dye, bound to the phenolic resin and, after the addition of PEO, yielded visible complex gels with diameters about 20 μm. © 1995 John Wiley & Sons, Inc.
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    Chemical modification of butyl rubber. III. Butyl rubber with D-maltose derivative as pendant groups (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2657-2665 
    Details
    ISSN: 0887-624X
    Keywords: amphiphilic rubber ; butyl rubber ; saccharide ; microphase-separated structure ; thermoplastic elastomer ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new type of amphiphilic elastomer was synthesized, which consisted of butyl rubber and a D-maltose derivative as a backbone and side groups, respectively. The synthesis was accomplished by the sequence of the three following reactions: (1) Hydroxyl groups of D-maltonolactone were protected by a trimethylsilyl group. (2) The resulting maltonolactone derivative was subjected to a reaction with chemically modified butyl rubber having pendant amino groups. (3) The protecting trimethylsilyl groups on the maltose residues were removed by treating with tetra-n-butylammonium fluoride. This new amphiphilic elastomer behaved as a thermoplastic elastomer and showed good mechanical properties. The saccharide seg-ments aggregated in the hydrophobic butyl rubber matrix to form a microphase-separated structure, as confirmed by differential scanning calorimetry, transmission electron mi-croscopy, small-angle x-ray scattering, and dynamic mechanical measurements. The ag-gregated saccharide domains are estimated to function both as crosslinking sites and rein-forcing fillers in the rubber matrix. © 1995 John Wiley & Sons, Inc.
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    Main chain liquid crystalline ionic polymers with thermotropic and lyotropic mesophases (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2673-2680 
    Details
    ISSN: 0887-624X
    Keywords: main chain LCPs ; ionic LCPs ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An ionogenic main chain liquid crystalline polymer was synthesized. In contrast to previous studies the charged sites were incorporated into the flexible spacer and not into the mesogenic group. This was done through quaternization of 1,2-bis(4-pyridylethane) with a biphenyl-4,4′-nonanoxytoluenesulphonate. The polymer displayed thermotropic and lyotropic me-sophases. The thermotropic mesophase was smectic. Organic counterions such as meth-ylsulfonates and p-toluenesulfonates were found to be favorable to the development of mesophases, due to the increased solubility and lower isotropisation temperatures, when compared to bromide counterion containing polymers. Easy supercooling, dependence on thermal history, and the development of batonnet textures on cooling from the melt were also observed. © 1995 John Wiley & Sons, Inc.
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    Reversible photodimerization of coumarin derivatives dispersed in poly(vinyl acetate) (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2705-2714 
    Details
    ISSN: 0887-624X
    Keywords: coumarin derivatives ; photodimerization ; photocleavage ; reversible ; pho-tosensitizer ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Four photoreactive coumarin derivatives were successfully synthesized from 7-hydroxy-coumarin and 7-hydroxy-4-methylcoumarin, i.e., 7-propionyloxy-4-methylcoumarin (M1), 7-palmitoyloxy-4-methylcoumarin (M2), 7-propionyloxycoumarin (M3), and 7-palmitoy-loxycoumarin (M4). Reversible photodimerization (350 or 300 nm) and photocleavage (254 nm) of these coumarin derivatives dispersed in poly(vinyl acetate) (PVAc) were investigated by tracing their UV absorbance variations at 310 nm. The M2 and M4 with long palmitoyl chain show much better photoreaction reversibility than M1 and M3 with short propionyl chain. Moreover, photodimerization rate (under 350 nm) of M2 is greater than 200 times of that of M1. This has been explained by the formation of suitable conformation for revers-ible photodimerization due to the hydrophobic interactions. Photodimerization of M2 is ca. 3 times quicker than that of M4, indicating 4-methyl substitution enhances pho-todimerization. The influence of photodimerization wavelength (350 and 300 nm) and photosensitizer (benzophenone) have also been investigated in detail. © 1995 John Wiley & Sons. Inc.
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  • 196
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    Characterization and comparison of poly(aryl ether ketone)s containing dibenzoylbiphenyl moieties: Effects of changes in biphenyl substitution pattern on thermal and mechanical properties (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2741-2752 
    Details
    ISSN: 0887-624X
    Keywords: 3,3′-bis (4-flurobenzoyl) biphenyl ; poly (aryl ether ketone)s ; spectroscopic prop-erties ; thermal properties ; thermomechancial properties ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A monomer, 3,3′-bis (4-fluorobenzoyl) biphenyl, was prepared in high yield in two steps from inexpensive 3-chlorobenzoyl chloride and fluorobenzene, and polymerized by nucleophilic displacement reaction with various bisphenol monomers in tetramethylene sulfone to produce a series of high molecular weight poly(aryl ether ketone)s containing 3,3′-dibenzoylbiphenyl (DBBP) moieties. The spectroscopic, thermal, and thermomechanical properties of these polymers and related isomeric polymers having 2,2′-and 4,4′-DBBP units were determined and compared to study the effects of changes in the substitution pattern of the biphenyl unit. Except for the 2,2′-DBBP series of polymers, Tgs were found to increase with increasing linearity of the DBBP unit. The 2,2′-DBBP series of polymers had exceptionally high Tgs due to the sterically restricted motions in the biphenyl unit caused by the 2,2′-substitution. In addition, they also showed evidence for torsion with the 2,2′-DBBP unit, whereas in other isomeric polymers the DBBP units are believed to be relatively coplanar. Thermal stabilities and tensile moduli for these polymers proved to be independent of substitution patterns. © 1995 John Wiley & Sons, Inc.
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    Olefin terpolymerizations. II. 4-vinylcyclohexene and cyclooctadiene (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2787-2793 
    Details
    ISSN: 0887-624X
    Keywords: Ziegler-Natta catalysis ; EPDM synthesis ; metallocene catalyst ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 4-Vinylcyclohexene (VCH) and cyclooctadiene (COD) were investigated as termonomers in EPDM (ethylene/propylene/diene) synthesis by using rac-ethylenebis (1-η5-indenyl) zir-conium dichloride (1) as a catalyst precursor. Homopolymerizations of VCH, vinylcycloh-exane and cyclohexene were compared. The parameter Kπκp, which is the apparent rate constant for Ziegler-Natta polymerization, is about the same for VCH and vinylcyclohexanebut is 10 times smaller for cyclohexene. Therefore, the linear olefinic double bond is more active than the cyclic internal double bond. VCH reduces ethylene polymerization rate but not propylene polymerization rate in copolymerizations. In terpolymerizations, VCH tends to suppress ethylene incorporation especially at elevated polymerization temperature and Lowers the polymer MW by about two-fold. COD has very low activity as a termonomer. © 1995 John Wiley & Sons, Inc.
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  • 198
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    Electronic Resource
    Radical polymerization behavior of ethyl ortho-formylphenyl fumarate involving intramolecular hydrogen abstraction (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2865-2873 
    Details
    ISSN: 0887-624X
    Keywords: fumarate ; radical polymerization ; addition-abstraction mechanism ; ESR spectrum ; propagation rate constant ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The radical polymerization behavior of ethyl ortho-formyl-phenyl fumarate (EFPF) using dimethyl 2,2′-azobisisobutyrate (MAIB) as initiator was studied in benzene kinetically and ESR spectroscopically. The polymerization rate (Rp) at 60°C was given by Rp = k[MAIB]0.76[EFPF]0.56. The number-average molecular weight of poly(EFPF) was in the range of 1600-2900. EFPF was also easily photopolymerized at room temperature without any photosensitizer probably because of the photosensitivity of the formyl group of monomer. Analysis of 1H- and 13C-NMR spectra of the resulting polymer revealed that the radical polymerization of EFPF proceeds in a complicated manner involving vinyl addition and intramolecular hydrogen-abstraction. The polymerization system was found to involve ESR-observable poly(EFPF) radicals under the actual polymerization conditions. ESR-determined rate constant (2.4-4.0 L/mol s) of propagation at 60°C increased with decreasing monomer concentration, which is mainly responsible for the observed low de-pendency of Rp on the EFPF concentration. Copolymerizations of EFPF with some vinyl monomers were also examined. © 1995 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1995.080331702
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  • 199
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    Novel copolyesters containing naphthalene structure. II. Copolyesters prepared from 2,6-dimethyl naphthalate, 1,4-dimethyl terephthalate, and ethylene glycol (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2841-2850 
    Details
    ISSN: 0887-624X
    Keywords: aromatic copolyesters ; poly(ethylene terephthalate) ; poly(ethylene naphtha-late) ; melt polycondensation ; physical properties ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Copolyesters containing rigid segments (naphthalene and terephthalene) and flexible seg-ments (aliphatic diol) structure were synthesized from DMN/DMT/EG (2,6-dimethyl naphthalate/1,4-dimethyl terephthalate/ethylene glycol) ternary monomers with various mole ratios. Copolyesters having intrinsic viscosities of 0.52-0.65 dL/g were obtained by melt polycondensation in the presence of metallic catalysts. The effect of reaction tem-perature and time on the formation of the copolyesters was investigated to obtain an op-timum condition for copolyester manufacturing. The optimum condition for PNT (poly-ethylene naphthalate terephthalate) copolyester manufacturing is the transesterification under nitrogen atmosphere for 4 h at a temperature of 185±2°C followed by polymerization under 2 mm Hg for 2 h at a temperature of 280°C. Most copolyesters have better solubilities than poly(ethylene naphthalate) (PEN) and poly(ethylene terephthalate) (PET) in various solvents. The effect of the starting mole ratio of DMN, DMT, and EG on the thermal properties of the resulted copolyesters was also investigated using differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Glass transition temperatures of copolyesters were in the range of 70.7-115.2°C, and 10% weight loss in nitrogen were all above 426°C. © 1995 John Wiley & Sons, Inc.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1995.080331618
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  • 200
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    Molecular composite fibers from rigid rod polymers and thermoset resin matrixes (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 2893-2899 
    Details
    ISSN: 0887-624X
    Keywords: poly(p-phenylenebenzobisthiazole) ; poly(p-phenylenebenzobisoxazole) ; fiber ; molecular composite fiber ; benzocyclobutene ; compressive strength ; tensile strength ; tensile modulus ; phase separation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Fibers consisting of a rigid rod polymer and thermoset resin matrices were prepared. Poly(benzo-[1,2-d : 5,4-d′]bisoxazole-2,6-diyl)-1,4-phenylene} (PBO) in polyphosphoric acid (PPA) was blended with isophthaloyl bis-4-benzocyclobutene (1) or 2,6-bis-4-benzocyclobutene benzo[1,2-d: 5,4-d′]bisoxazole (2), and fibers were spun from these dopes. As-spun fibers that did not show phase segregation between the two components as examined with an optical microscope, were soluble in methanesulfonic acid (MSA). After heat treat-ment, the fibers swelled but did not dissolve in MSA. A fiber cross section of heat-treated PBO-1 fiber showed well-dispersed benzocyclobutene polymer domains of 200-500 Å by transmission electron microscopy (TEM). Films cast from MSA solutions of PBO and 2 were homogeneous, and TEM of heat-treated fiber showed only one phase. A molecular composite fiber was made. Some of these fibers showed 20-30% improvement in compressive strength over unmodified PBO fiber. © 1995 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1995.080331706
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