Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1985-1989  (223)
  • 1988  (223)
  • Rat  (167)
  • Industrial Chemistry
  • Nuclear reactions
  • 101
    Electronic Resource
    Electronic Resource
    Rapid effects of adult-onset hypothyroidism on dendritic spines of pyramidal cells of the rat cerebral cortex (1988)
    Springer
    Experimental brain research 73 (1988), S. 583-588 
    Details
    ISSN: 1432-1106
    Keywords: Adult hypothyroidism ; Dendritic spines ; Pyramidal cells ; Cerebral cortex ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have previously shown (Ruiz-Marcos et al. 1980, 1982) that thyroidectomy (T) performed in rats at 40 days of age, well past the neonatal period of development, results by 80–90 days of age in a decrease of the number of spines along the shaft of pyramidal neurons with the cell body in layer V in the visual area of the cerebral cortex. We have here studied how soon after the operation an effect on spine number and distribution may be observed. We have found that the response of these neurons to T is very rapid: a decrease in the number of spines/shaft between T and age-paired controls (C) rats is statistically significant by the earliest period of observation, namely 5 days after T. These results may be related to those of Dembri et al. (1983) showing that T performed in adult rats decreases the activity of Type I RNA polymerase by 5 days after the operation. It is possible that T impairs the synthesis of some compound(s) necessary for the formation and maintenance of spines. The present results suggest that spine number is not a fixed structure of the apical shaft once brain development is over, but is in a state of continuous formation and degradation. We have further observed that the effect of T performed at 40 days of age is more pronounced in the distal part of the shaft than on the rest, a result similar to that found after neonatal T (Ruiz-Marcos et al. 1982). However, contrary to findings after early hypothyroidism, T at 40 days of age does not distort the distribution of spines along the shaft.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00406617
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 102
    Electronic Resource
    Electronic Resource
    Characterization of the scopolamine stimulus in rats (1988)
    Springer
    Psychopharmacology 95 (1988), S. 195-199 
    Details
    ISSN: 1432-2072
    Keywords: Drug discrimination ; Scopolamine cue ; Muscarinic agonists ; Muscarinic antagonists ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The discriminative stimulus properties of scopolamine, a potent antagonist at muscarinic receptors, were used for testing the discriminative effects of drugs known to act on cholinergic transmission. Rats were trained in a standard two-bar operant conditioning procedure with food as the reinforcer, according to a FR10 schedule. The training dose of scopolamine was progressively reduced from 0.25 mg/kg SC to the low dose of 0.062 mg/kg SC. Scopolarmine yielded an accurate discrimination in all the six rats tested. The generalization gradient resulted in an ED50 of 0.027 mg/kg. The scopolamine cue lasted for 1 h and was of central origin, since it was not mimicked by scopolamine methylbromide. The scopolamine stimulus generalized to atropine and trihexyphenidyl (respective ED50 values 2.20 and 0.21 mg/kg SC). Atropine depressed rate of responding, while trihexyphenidyl did not. Antagonism experiments with both direct agonists at the muscarinic receptor (arecoline and oxotremorine) and indirect agonists, i.e., inhibitors of the acetylcholine esterase [physostigmine and tetrahydroaminoacridine (THA)], led to inconsistent results. Increasing the doses of the agonists in order to block the scopolamine cue may be limited by their rate suppressant effect on responding. Based upon previously published results, it is suggested that the muscarinic agonist cue is more useful than the antagonist cue for investigating muscarinic transmission.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00174509
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 103
    Electronic Resource
    Electronic Resource
    Long-term attentional deficit in nonhandled males: possible involvement of the dopaminergic system (1988)
    Springer
    Psychopharmacology 95 (1988), S. 231-236 
    Details
    ISSN: 1432-2072
    Keywords: Latent inhibition ; Early handling ; Haloperidol ; Amphetamine ; Male ; Female ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Latent inhibition (LI) is a behavioral paradigm in which nonreinforced pre-exposure to a stimulus retards subsequent conditioning to that stimulus. The development of LI is considered to reflect learning not to attend to, or ignore, irrelevant stimuli. In our previous studies investigating the effects of early handling on LI, we have shown that normal LI was obtained in handled males and females, as well as in nonhandled females. In contrast, nonhandled males failed to show LI. This finding pointed to a long-term attentional deficit in nonhandled males. Since there is evidence that the development of LI is mediated by the dopaminergic system, the present experiments tested the possibility that the attentional deficit of nonhandled males may be related to a dopaminergic dysfunction. Experiment 1 tested whether the administration of haloperidol, which was shown to enhance LI in normal animals, would reinstate the LI effect in nonhandled males. Infantile handled (Days 1–22) and nonhandled male and female rats were tested in maturity in the LI paradigm, using a conditioned emotional response procedure. Experiment 2 tested the locomotor response of handled and nonhandled males to 0.3, 1 and 2.5 mg/kg d-amphetamine. Experiment 1 showed that handled males, handled females and nonhandled females showed a normal LI effect, whereas nonhandled males failed to develop LI. Haloperidol enhanced LI in all the groups, but this effect was most dramatic in nonhandled males, in which the drug reinstated LI. Experiment 2 showed that nonhandled males exhibited a reduced locomotor response to d-amphetamine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00174515
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 104
    Electronic Resource
    Electronic Resource
    Behavioral evidence for the role of noradrenaline in putative anxiolytic and sedative effects of benzodiazepines (1988)
    Springer
    Psychopharmacology 95 (1988), S. 280-286 
    Details
    ISSN: 1432-2072
    Keywords: Benzodiazepines ; Triazolopyridazines ; Noradrenaline ; Clonidine ; Yohimbine ; Drug discrimination stimulus ; Fixed ratio performance ; Bicuculline ; Ro 15-1788 ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of clonidine on the antianxiety and sedation of benzodiazepines (BZD) were assessed respectively in rats trained in a two-lever diazepam cue discrimination procedure and in single-lever fixed-ratio (FR) water-reinforced performance. Clonidine (10–60 μg/kg) significantly shifted to the left the dose-effect curves of diazepam in the discrimination paradigm. This treatment also shifted generalization dose-effect curves of the diazepam cue to chlordiazepoxide and CL 218872 to the left in the drug discrimination procedure. The diazepam cue was antagonized in a dose-related manner by Ro 15-1788, but not by bicuculline. Clonidine also potentiated the rate-decreasing effects of diazepam on the FR schedule when the dose of diazepam was increased to 0.3 mg/kg, but not the milder rate-decreasing effect of CL 218872 until the dose of CL 218872 was increased to 10 mg/kg. The potentiating effects of clonidine on the stimulus control and depression of diazepam were antagonized by yohimbine. Yohimbine (1.0 mg/kg) also significantly shifted the dose-effect curve of diazepam cue to the right. Bicuculline (3 mg/kg) completely antagonized the rate-decreasing effect of diazepam (1 mg/kg), but significantly potentiated the rate-suppressant effect of clonidine (10 μg/kg). These results suggest that the central noradrenaline (NA) system may be involved not only in the antianxiety, but also the sadative action of BZD. The nature of NA involvement in relation to the different subtypes of BZD receptors requires further exploration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00174525
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 105
    Electronic Resource
    Electronic Resource
    Differential effects of the selective D2-antagonist raclopride in the nucleus accumbens of the rat on spontaneous and d-amphetamine-induced activity (1988)
    Springer
    Psychopharmacology 95 (1988), S. 447-451 
    Details
    ISSN: 1432-2072
    Keywords: Nucleus accumbens ; d-Amphetamine activity ; Exploration ; Raclopride ; D2-receptors ; Schizophrenia ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effect of the D2-antagonist raclopride was investigated in two test situations, which are presumed to involve dopamine (DA) transmission within the nucleus accumbens of the rat. Local injection of d-amphetamine sulphate (10 μg/0.5 μl) produced a marked increase in motor activity, measured as motility, locomotion, and rearing, which was dose- and time-dependently antagonised by local injection of raclopride (0.05–5.0 μg/0.5 μl). After an initial decrease, at low doses (0.05–0.25 μg/0.5 μl) an apparent enhancement of the d-amphetamine-induced motor activity appeared, which was most clearly seen with rearing. These lower doses, however, did not induce any clear changes in the exploratory activity in a novel environment (i.e., the second test situation). Only the higher doses used (1.0–5.0 μg/0.5 μl) decreased exploratory activity during the first 5–10 min, also measured as motility, locomotion, and rearing. These data are discussed with respect to the role of D2-receptors within the nucleus accumbens of rats in the motor activity induced by a novel environment and d-amphetamine. Overall, the data underline previous notions that raclopride is a potent antagonist of DA-mediated behaviour.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00172953
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 106
    Electronic Resource
    Electronic Resource
    Clonidine infusions into the locus coeruleus attenuate behavioral and neurochemical changes associated with naloxone-precipitated withdrawal (1988)
    Springer
    Psychopharmacology 96 (1988), S. 121-134 
    Details
    ISSN: 1432-2072
    Keywords: Clonidine ; Locus coeruleus ; Intracerebral infusion ; Withdrawal ; Naloxone ; Morphine ; 3-Methoxy-4-hydroxyphenylglycol (MHPG) ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Clonidine, an alpha-2-adrenergic agonist, suppresses signs of opiate withdrawal in animals and in man. Electrical or chemical stimulation of the nucleus locus coeruleus (LC) increases noradrenergic activity and brain concentration of the noradrenergic metabolite MHPG, and produces many signs of opiate withdrawal. Thus, clonidine's ability to attenuate withdrawal might be due to the reduction of noradrenergic neuronal activity originating in the LC, but additional alpha-2-adrenergic receptors throughout the body and other mechanisms may also play a role. The present study explored the neuroanatomical and pharmacological selectivity of alpha-2-adrenergic receptors of the LC in the anti-withdrawal action of clonidine. Experiment 1 tested the hypothesis that behavioral and biochemical measures of naloxone-precipitated withdrawal from morphine would be blocked by infusions of clonidine (0.6 or 2.4 μg/μl) into the LC. Significant reductions were observed in the occurrence of diarrhea, ptosis, weight loss and wet-dog shakes. Clonidine also reversed the naloxone-precipitated increase in hippocampus MHPG concentration. In experiment 2 subjects received an LC infusion or IP injection of a non-lipophilic alpha-2-agonist (ST-91), which does not penetrate the blood-brain barrier, or of clonidine into the dorsal parabrachial nucleus (DPB) to test the selectivity of the effects of clonidine infusions into the LC. ST-91 infusions into the LC reduced several of the observed withdrawal signs and increased others (e.g., jumping). Although peripheral injections of ST-91 attenuated some of the checked signs associated with naloxone-precipitated withdrawal, the frequency of wet-dog shakes was not reduced. ST-91 infusions into the LC, but not systemic ST-91 administration, prevented the withdrawal-induced increase in hippocampus MHPG concentration. Clonidine infused lateral to the LC into the DPB did not significantly attenuate withdrawal or reduce hippocampus MHPG levels. These results provide behavioral and biochemical evidence to support the suggestion that clonidine significantly attenuates naloxone-precipitated withdrawal through an interaction with noradrenergic neurons located in the vicinity of the LC.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02431544
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 107
    Electronic Resource
    Electronic Resource
    Delay-dependent short-term memory deficits in aged rats (1988)
    Springer
    Psychopharmacology 96 (1988), S. 174-180 
    Details
    ISSN: 1432-2072
    Keywords: Aging ; Short-term memory ; Delayed response ; Delayed matching ; Delayed non-matching ; Arecoline ; Physostigmine ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Separate groups of rats of three ages (6 month, 15 month or 24 month) were trained in a two-lever operant chamber on one of two versions of a paired-trial delayed response task involving either matching or non-matching of the choice response to a sample lever. The older rats were unimpaired in learning either version of the task during initial training with no (0 s) delay between the sample and choice responses. However, when variable 0–24 s delay intervals were introduced, the 24-month group was impaired on acquisition of the delayed non-matching task, and both the 15- and 24-month groups were impaired on acquisition of the delayed matching task compared to the 6-month group. Deficits in the older groups in asymptotic performance were attributable to an impairment at longer delay intervals whilst maintaining near perfect performance at the shorter delay intervals, suggesting a selective short-term memory impairment. The delay-dependent deficits of the older groups were not ameliorated by the muscarinic agonist arecoline or the cholinesterase inhibitor physostig-mine, and so failed to corroborate a cholinergic interpretation of the observed age-related impairment in short-term memory.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00177557
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 108
    Electronic Resource
    Electronic Resource
    Hangover hyperthermia in rats: relation to tolerance and external stimuli (1988)
    Springer
    Psychopharmacology 94 (1988), S. 161-166 
    Details
    ISSN: 1432-2072
    Keywords: Hangover ; Thermoregulation ; Tolerance ; Ethanol ; Stress ; Compensatory reactions ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The recent finding of rebound hyperthermia in rats on the day after a single IP injection or oral intubation of ethanol was confirmed. In our studies, body temperature measured by rectal probe was significantly decreased for 8 h after 2.5 g/kg ethanol IP and was then significantly elevated 16–24 h after injection; increased vocalization during handling at 24 h was also found. However, rats isolated in a sound-attenuation chamber with remote temperature measurement showed no hyperthermia even though they were hypothermic during intoxication. The results do not support the hypothesis that rebound hyperthermia was caused by either a disruption of circadian rhythms, or by a mild abstinence syndrome alone. Instead, it appears that external stimuli, perhaps related to stress or associated with ethanol administration, are necessary on the day after a moderate dose of ethanol to produce the hyperthermia. Like hangover in humans, hyperthermia was reduced in rats made tolerant to ethanol: both the hypothermia and the rebound hyperthermia were significantly lower on the day after the 12th alternate-day ethanol injection than after the first injection. The aftereffects in rats of acute intoxication are, by definition, hangover signs, and they resemble hangover in humans in several ways, but their relevance as an animal model of hangover remains to be determined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00176838
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 109
    Electronic Resource
    Electronic Resource
    Changes in auditory evoked responses and in the inhibitory action of 5-hydroxytryptophan following chronic treatment with imipramine in the rat (1988)
    Springer
    Psychopharmacology 96 (1988), S. 408-413 
    Details
    ISSN: 1432-2072
    Keywords: 5-Hydroxytryptophan ; Imipramine ; Brainstem auditory evoked response ; Middle latency auditory evoked response ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The neurophysiological effects of acute and chronic treatment with the tricyclic antidepressant drug imipramine were investigated. Brainstem (BAER) and middle latency (MLR) auditory evoked responses were monitored in the alert and immobile rat. Daily injection of imipramine (10 mg/kg, IP) for 2 weeks produced a 13% increase in the latency and a 35% reduction in the amplitude of the N17 component of the MLR. Acute imipramine treatment had no effect. There was no observable change in the BAER after either acute or chronic drug administration. Serotonergic function was assessed by studying the inhibitory effects of 5-hydroxytryptophan on the BAER and MLR. Chronic application of imipramine caused an apparent reduction of the effects of 5-hydroxytryptophan (75 mg/kg, IP) on the N17 component of the MLR. This may, however, be due to the shift in baseline latency and amplitude. Inhibition of the BAER by 5-hydroxytryptophan was unaltered by long term exposure to imipramine. Acute treatment with imipramine was without effect on the modulation of the BAER and the MLR by 5-hydroxytryptophan. These results provide evidence that chronic, as opposed to acute, administration of imipramine had an inhibitory effect on auditory processing at the level of the MLR and that this may be associated with a change in the net output of the serotonergic system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216071
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 110
    Electronic Resource
    Electronic Resource
    Morphine induces delayed anorexia in rats (1988)
    Springer
    Psychopharmacology 94 (1988), S. 254-258 
    Details
    ISSN: 1432-2072
    Keywords: Anorexia ; Feeding ; Hyperphagia ; Morphine ; Naltrexone ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The delayed suppression of feeding caused by morphine was investigated in the rat. A single injection of morphine evoked a triphasic influence on feeding: a brief (1 h) severe anorexia was followed by hyperphagia (3 h) and a mild (20%) yet persistent (4–24h) anorexia. This latter anorexic effect was at least partially naltrexone reversible, and the duration of this antagonism (8 h) was longer than that of naltrexone's anorexic effect (4 h). Delayed morphine anorexia cannot be ascribed to morphine's initial stuporific influence, and it was not dependent upon previous feeding or deprivation. It was not due to gastric distension. The specificity and significance of this anorexia is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00176855
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 111
    Electronic Resource
    Electronic Resource
    Repeated electroconvulsive shock does not change [3H]-paroxetine binding to the 5-HT uptake site in rat cortical membranes (1988)
    Springer
    Psychopharmacology 95 (1988), S. 68-70 
    Details
    ISSN: 1432-2072
    Keywords: Electroconvulsive shock ; 5-HT transporter complex ; β-Adrenoceptor ; [3H]-Paroxetine ; [3H]-Imipramine ; [3H]-Dihydroalprenolol ; Cerebral cortex ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of repeated electroconvulsive shock on the 5-HT uptake site were studied in rat cortex using [3H]-paroxetine binding. This ligand was used because it is thought to directly label the 5-HT uptake site, whereas [3H]-imipramine may bind to a presynaptic recognition site different from the uptake site. No changes were found in the maximum number of [3H]-paroxetine binding sites and equilibrium dissociation constant after repeated electroconvulsive shock, whereas a parallel investigation of β-adrenoceptor binding showed the expected decrease in receptor number.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00212769
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 112
    Electronic Resource
    Electronic Resource
    Apomorphine, d-amphetamine, strychnine and yohimbine do not alter prepulse inhibition of the acoustic startle reflex (1988)
    Springer
    Psychopharmacology 95 (1988), S. 151-156 
    Details
    ISSN: 1432-2072
    Keywords: Apomorphine ; Amphetamine ; Strychnine ; Yohimbine ; Acoustic startle reflex ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Rats were presented with noise bursts alone or noise bursts 60 ms after presentation of either a 60 dB or an 80 dB prepulse after injection of the dopamine agonists apomorphine (3 mg/kg) or d-amphetamine (4 mg/kg), the glycine antagonist strychnine (1.5 mg/kg) or the α2 antagonist yohimbine (5 mg/kg). Presentation of prepulses inhibited startle, with greater inhibition following an 80 dB versus 60 dB prepulse. Apomorphine, d-amphetamine and strychnine increased overall startle levels but did not attenuate prepulse inhibition, since the absolute change in startle following prepulse presentation was significantly greater after administration of these drugs. A lower dose of apomorphine also increased startle but had no effect on prepulse inhibition using test intervals of 10, 60, 100, 200 or 1000 ms. While these drugs did decrease per cent prepulse inhibition, this seemed wholly attributable to their increasing overall startle levels, rather than a real attenuation of prepulse inhibition. Yohimbine did not alter either startle baseline or prepulse inhibition. The results do not support the conclusion that overactivity of dopamine systems attenuates prepulse inhibition and, in addition, suggest that prepulse inhibition does not result from activation of either glycine or norepinephrine projecting to α2 adrenergic receptors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00174500
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 113
    Electronic Resource
    Electronic Resource
    Effects of nimodipine on the discriminative stimulus properties ofd-amphetamine in rats (1988)
    Springer
    Psychopharmacology 96 (1988), S. 40-44 
    Details
    ISSN: 1432-2072
    Keywords: Drug discrimination ; d-Amphetamine ; Nimodipine ; Diazepam ; Morphine ; Haloperidol ; Calcium channel ; Behavior ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The discriminative stimulus (DS) properties ofd-amphetamine (AMP) are thought to be mediated by enhanced release of catecholamines, which may involve neuronal calcium influx through voltage sensitive channels. The present study examined the influence of nimodipine, a calcium channel blocker, on the DS properties of AMP. Rats (N=8) were trained to discriminate AMP (0.5 mg/kg, IP) from saline in a two-lever, food-reinforced, drug discrimination paradigm. Nimodipine alone (2.0–5.6 mg/kg, IP) did not substitute for AMP. When given in combination with AMP, 2.0 mg/kg nimodipine increased by less than 2-fold the AMP dose necessary to induce AMP-appropriate responses. Higher doses of nimodipine combined with AMP did not increase the magnitude of this effect. Nimodipine enhanced the effects of AMP on response rate. Haloperidol (0.125 mg/kg) increased by approximately 4-fold, whereas diazepam (0.5 or 1.0 mg/kg) and morphine (5.0 mg/kg) increased by approximately 2-fold the AMP dose necessary to induce AMP-appropriate responses. The interaction with AMP was associated with enhanced reduction of response rate in the tests with diazepam and morphine but not haloperidol. These results suggest that nimodipine attenuates the DS properties of AMP, probably in a non-specific way, due to the ability of nimodipine itself to induce a discriminable internal state.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02431531
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 114
    Electronic Resource
    Electronic Resource
    Is the discriminative stimulus produced by phencyclidine due to an interaction with N-methyl-d-aspartate receptors? (1988)
    Springer
    Psychopharmacology 96 (1988), S. 87-92 
    Details
    ISSN: 1432-2072
    Keywords: Rat ; Drug discrimination ; NMDA ; Phencyelidine ; ±SKF 10047 ; MK 801 ; CPP ; Ifenprodil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Rats were trained to discriminate phencyclidine (PCP) from saline at doses of 2 and 4 mg/kg, using a two-lever food reinforced operant technique. ±N-allylnormetazocine (±SKF 10047), +5-methyl-10,11-dihydro-5H-dibenzo[A,D]cyclohepten-5,10-imine (MK 801), 3-(2-carboxypiperazin-4-yl) propyl-1-phosphonic acid (CPP) and ifenprodil, which have been shown to antagonise the effects of N-methyl-d-aspartate (NMDA), were tested for their ability to give rise to PCP-appropriate responding. In rats trained at both doses of PCP, ±SKF 10047 (2–12 mg/kg) and MK 801 (0.0125–0.2 mg/kg) produced dose-related responding on the lever associated with PCP injection. The relative potency of these two compounds was the same in the two groups of animals, but their absolute potencies to produce a PCP-like discriminative stimulus were dependent on the training dose of PCP. In contrast, neither the competitive NMDA antagonist CPP (4–20 mg/kg) nor the non-competitive antagonist ifenprodil (2–12 mg/kg) produced PCP-appropriate responding and ifenprodil (4-mg/kg) neither potentiated nor antagonised PCP. These findings are discussed in the light of the hypothesis that the behavioural effects of PCP are mediated via a reduction of neurotransmission at the NMDA-subtype of glutamate receptors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02431538
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 115
    Electronic Resource
    Electronic Resource
    Tolerance and selective cross-tolerance to the motivational effects of opioids (1988)
    Springer
    Psychopharmacology 96 (1988), S. 110-115 
    Details
    ISSN: 1432-2072
    Keywords: Tolerance ; Opioids ; Reinforcement ; Place conditioning ; Morphine ; U-69593 ; d-Amphetamine ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The issue of whether tolerance develops to the motivational effects of opioids was addressed by use of an unbiased place preference conditioning procedure. Administration of the μ-opioid agonists morphine or fentanyl produced dose-related preferences for the drug-associated place in control rats. In contrast, the κ-opioid agonist, U-69593 produced conditioned place aversions. Non-contingent administration of morphine (5.0 mg/kg/12 h) for 4 days prior to conditioning resulted in tolerance to its reinforcing effects, and cross-tolerance to the effects of fentanyl. No cross-tolerance to the motivational effects of the psychostimulantd-amphetamine or the κ-opioid agonist U-69593 was observed. Chronic administration of U-69593 prior to conditioning produced tolerance to its aversive effects. This treatment did not, however, modify the reinforcement produced by morphine. These data demonstrate that tolerance develops to both the reinforcing and aversive properties of opioids and suggest that differential cross-tolerance may provide a useful method for determining the pharmacological basis underlying drug-induced motivational effects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02431542
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 116
    Electronic Resource
    Electronic Resource
    Potential interactions between GABAb and cholinergic systems: baclofen augments scopolamine-induced performance deficits in the eight-arm radial maze (1988)
    Springer
    Psychopharmacology 96 (1988), S. 116-120 
    Details
    ISSN: 1432-2072
    Keywords: Radial maze performance ; Motor activity ; Pharmacological interactions ; Baclofen ; Scopolamine ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Sixteen male Fischer-344N rats were trained on a eight-arm radial maze task for food reinforcement. The effects of various doses of baclofen (1.25 or 2.50 mg/kg) and scopolamine (0.188, 0.375, and 0.750 mg/kg) were determined alone and in combination. Relative to vehicle controls, baclofen alone did not affect performance in the radial arm maze (number correct in the first eight responses, total errors) or the time required to complete the maze. Scopolamine alone decreased the number of correct responses in the first eight arm choices, while increasing both the number of errors and the time necessary to complete the maze. When the two drugs were co-administered, baclofen had no effect on the number of errors or time required to complete the maze in the presence of scopolamine; however, in combination with the high dose of scopolamine, it significantly inreased the number of errors made during the first eight choices. Baclofen thus can exacerbate some radial arm maze dificits produced by an anticholinergic drug. In a subsequent experiment to test the interaction between scopolamine and baclofen using a nonlearned behavior, baclofen (1.25 and 2.5 mg/kg) did not affect motor activity, whereas all doses of scopolamine (0.188–0.75 mg/kg) increased activity. The higher dose of baclofen attenuated scopolamine-induced hypermotility by 50%, but the lower dose of baclofen was not effective. These data demonstrate pharmacological interactions between baclofen, a drug used clinically for spaticity, and a drug having anticholinergic properties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02431543
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 117
    Electronic Resource
    Electronic Resource
    Facilitation of brain stimulation reward byΔ 9-tetrahydrocannabinol (1988)
    Springer
    Psychopharmacology 96 (1988), S. 142-144 
    Details
    ISSN: 1432-2072
    Keywords: Marijuana ; Cannabis ; Cannabinoids ; Δ 9-tetrahydrocannabinol ; THC ; Brain stimulation reward ; Intracranial self-stimulation ; ICSS ; Reinforcement ; Medial forebrain bundle ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The present experiment explored whetherΔ 9-tetrahydrocannabinol (Δ 9-THC), the psychoactive ingredient in marijuana, shares with other drugs of abuse the ability to facilitate brain stimulation reward acutely, as measured by clectrical intracranial self-stimulation (ICSS). Laboratory rats were implanted with stimulation electrodes in the medial forebrain bundle, and trained to stable performance on a self-titrating threshold ICSS paradigm.Δ 9-THC, at a dose believed pharmacologically relevant to moderate human use of marijuana, acutely lowered ICSS thresholds, suggesting that marijuana acts on similar CNS hedonic systems to most other drugs of abuse.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02431546
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 118
    Electronic Resource
    Electronic Resource
    Apomorphine anorexia: the role of dopamine receptors in the ventral forebrain (1988)
    Springer
    Psychopharmacology 96 (1988), S. 135-141 
    Details
    ISSN: 1432-2072
    Keywords: Apomorphine ; Sulpiride ; SCH-23390 ; Central drug administration ; Dopamine autoreceptors ; Feeding behaviour ; Microstructural analysis ; Eating rate ; Eating time ; Open field ; Nucleus accumbens ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The inhibition of feeding following the administration of apomorphine, systemically or directly into the nucleus accumbens/ventral striatum, was studied using a microstructural analysis paradigm. On systemic administration, apomorphine reduced food consumption, eating rate and eating time; the effects were blocked by sulpiride but not by SCH-23390. Two doses of apomorphine were administered centrally. Both doses reduced total food intake and eating rate; only the higher dose also reduced eating time; all of these effects were blocked by sulpiride pretreatment. Only the lower dose reduced locomotor activity and rearing in the open field. The results suggest that apomorphine reduces eating rate by an action on dopamine (DA) axon terminal autoreceptors. We have previously demonstrated that apomorphine reduces eating time by an action on DA cell body autoreceptors. Therefore, the two populations of DA autoreceptors appear to be differentially involved in behaviour.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02431545
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 119
    Electronic Resource
    Electronic Resource
    Interaction between ethanol and caffeine in operant behavior of rats (1988)
    Springer
    Psychopharmacology 96 (1988), S. 194-205 
    Details
    ISSN: 1432-2072
    Keywords: Caffeine ; Ethanol ; Interaction ; Rat ; Operant behavior ; Spatial alternation ; Microanalysis of behavior ; Blood levels
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The interaction between ethanol and caffeine on operant behavior was studied in 24 water-deprived male rats trained in a discrete trial spatial alternation schedule with water as reinforcer. One single drug dose-response experiment or one dose combination of ethanol and caffeine (including the associated control treatments) was run on 4 successive days in 1 week. The four treatments of 1 week were administered to each animal in a distinct order according to the 24 possible permutations. In the single drug weeks, ethanol (0.25, 0.5, 0.75 and 1.0 g/kg IP) or caffeine (5, 10, 20, and 40 mg/kg PO) were administered 15 min before the session. In four interaction experiments all combinations of two doses of ethanol (0.5 and 1.0 g/kg IP) and two doses of caffeine (25 and 50 mg/kg PO) were employed. Ethanol and caffeine alone showed both dose-dependently decreased choice accuracy and increased response latency and passiveness. In combination, caffeine normalized the ethanol-induced alterations in ITI response rate and pause length but potentiated the effects on choice accuracy, latency and number of pauses. The results are interpreted in terms of effects of these drugs on attentional and arousal processes, and the test procedure is proposed as a screening tool for the preclinical assessment of ethanol-drug interactions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00177560
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 120
    Electronic Resource
    Electronic Resource
    Electron microscopic results on the ventral prostate of the rat after CdCl2 administration. A contribution towards etiology of the cancer of the prostate (1988)
    Springer
    Journal of cancer research and clinical oncology 114 (1988), S. 273-278 
    Details
    ISSN: 1432-1335
    Keywords: Prostate ; Rat ; Electron microscope
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The prostate epithelium of rats which received repeated cadmium chloride (CdCl2) injections showed a gradual disruption of structural differentiation. Electron microscopy studies revealed severe changes in the ultrastructure affecting all epithelial cell organelles, particularly the nuclei, rough endoplasmatic reticulum, the golgi apparatus, and mitochondria. The cells infiltrating the stroma contained secretory vacuoles and their nuclear evaginations on the invasion front showed similarities to ultrastructural pathological changes in man. Examination of the ventral prostate following oral CdCl2 administration revealed changes ranging in severity up to dysplasia, but there was no evidence of carcinoma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00405833
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 121
    Electronic Resource
    Electronic Resource
    Changes in brain temperature and free amino acids in normal and protein deprived suckling rats exposed to room temperature (1988)
    Springer
    Neurochemical research 13 (1988), S. 657-661 
    Details
    ISSN: 1573-6903
    Keywords: Rat ; protein deprivation ; brain ; temperature ; amino acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Previous reports on early-induced protein-calorie malnutrition (PCM) in rats have indicated alterations in the concentration of free amino acids and of protein synthesis in the brain. Recently it was shown that early-induced protein deprivation (PD) retards the development of thermoregulation. This resulted in a failure to maintain a normal rectal temperature after short exposure to room temperature (+22°C) still at the age of 20–25 days corresponding to changes seen in normal rats at an age of 10–15 days. In the present study, 20-day old PD and normal rats where examined with regard to the effect of exposure to room temperature on brain temperature and on brain free amino acids. The results show a similar reduction in brain and rectal temperature of the PD rats occuring within 30 minutes after exposure to room temperature. The reduction was in the range of 5°C. PD rats kept in room temperature for 5 hours and then allowed to recover at 32.5°C showed a slow increase in brain and rectal temperature but normal temperatures were not reached even after 1 hour. The concentration of free amino acids in the brain was examined in rats kept for 1 hour at room temperature or at 32.5°C. In the PD rats kept at 32.5°C, free aspartate and glutamate were reduced whereas taurine, GABA and glycine were increased as compared to their corresponding control rats. As a result of the reduced brain temperature in PD rats exposed to room temperature there was a reduction in free asparagine. The lability of the pool of asparagine may be related to the low levels of aspartate and glutamate in PD rats. On the basis of the present findings it is recommended that temperature-sensitive parameters are examined in PCM rats at a normal body temperature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00973284
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 122
    Electronic Resource
    Electronic Resource
    Somatostatin-gastrin interactions in the rat stomach (1988)
    Springer
    Research in experimental medicine 188 (1988), S. 115-121 
    Details
    ISSN: 1433-8580
    Keywords: Gastrin ; Rat ; Somatostatin ; Stomach
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Low concentrations of somatostatin and gastrin within or slightly above the range of physiologically circulating levels were perfused in the isolated, vascularly perfused rat stomach preparation. Somatostatin at 10 and 50 pg/ml significantly inhibited acetylcholine-stimulated gastrin secretion by 26% and 45%, respectively, whereas perfusion of 50 and 500 pg/ml exogenous gastrin did not modify gastric somatostatin secretion. Perfusion of somatostatin-antiserum significantly increased gastrin release by 235%. It is concluded that (1) somatostatin is a powerful inhibitor of the gastrin cell under in vitro conditions; the data are in accordance with a concept that endogenous somatostatin could act as a true hormone; (2) the secretory activity of the somatostatin cell is not significantly affected by circulating gastrin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01852267
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 123
    Electronic Resource
    Electronic Resource
    Intestinal ammonium production in the rat: The role of the colon, small intestine, and circulating glutamine (1988)
    Springer
    Research in experimental medicine 188 (1988), S. 1-7 
    Details
    ISSN: 1433-8580
    Keywords: Rat ; Intestinal ammoniagenesis ; Glutamine metabolism ; Small intestine ; Colon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The intestinal ammonium production and the intestinal uptake of circulating glutamine were investigated in anesthetized intact rats and rats with resected small intestine or colon by simultaneous measurements performed on portal and arterial blood. It was shown that ammonium release into the portal blood by the small intestine is of equal magnitude to that released by the colon, and that circulating glutamine participates in ammonium production by the small intestine. Increased levels of circulating glutamine induced by its i.v. infusion to intact rats were not accompanied by an increase in intestinal ammonium production.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01852088
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 124
    Electronic Resource
    Electronic Resource
    When should treatment of acute experimental pancreatitis be started? (1988)
    Springer
    Research in experimental medicine 188 (1988), S. 123-129 
    Details
    ISSN: 1433-8580
    Keywords: Acute experimental pancreatitis ; Sodium taurocholate ; Pancreatic enzymes ; Pancreatic morphology ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Sodium taurocholate pancreatitis in the rat is a frequently used experimental model for evaluating therapeutical regimes in this disease. It is, however, uncertain when treatment should be started, as the early phase of this experimental model and thus the time when the pancreatitis really develops is unknown. Serum and pancreatic enzymes, as well as pancreatic morphology, were therefore studied 5, 30, and 60min after induction of sodium taurocholate pancreatitis. It was found that increase in serum enzymes and decrease in pancreatic enzymes and morphological changes characteristic for acute pancreatitis develop as early as 5 and 30 min after induction of pancreatitis. Thus, therapy in this model may be started shortly after induction of acute pancreatitis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01852268
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 125
    Electronic Resource
    Electronic Resource
    Malaria infection in rats with stimulated splenic red pulp: The blood flow and protective effect in normal and transplanted splenic tissue (1988)
    Springer
    Research in experimental medicine 188 (1988), S. 267-276 
    Details
    ISSN: 1433-8580
    Keywords: Splenic autotransplantation ; Phenylhydrazine ; Malaria infection ; Rat ; Blood flow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary After splenic autotransplantation both weight and blood flow of the regenerated splenic tissue are decreased. In addition, the protective function of the transplant is less compared to that of the normal spleen. In the present study, the red pulp of normal and transplanted splenic tissue was stimulated by injections of phenylhydrazine to increase the weight, the blood flow, and the protective function. After stimulation, the weight of the normal spleen increased to 900 ± 70 mg (control 530 ± 20 mg) and the transplanted tissue to 240 ± 70 mg (control 70 ± 20 mg). This enlargement was caused by an increase in the splenic red pulp. However, the relative blood flow decreased in both the normal spleen and the transplant to 50% of the normal value. To evaluate the protective function of the stimulated splenic tissue, normal, splenectomized and transplanted rats were infected withPlasmodium berghei. Despite the dramatic increase in the red pulp, neither the normal nor the transplanted animals showed a survival rate superior to that of the splenectomized animals. The mass of splenic tissue obviously does not correlate with the protective effect of the spleen in parasitic infections.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01852275
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 126
    Electronic Resource
    Electronic Resource
    Laser welded vascular anastomosis (1988)
    Springer
    Urological research 16 (1988), S. 127-131 
    Details
    ISSN: 1434-0879
    Keywords: Microsurgery ; CO2 laser ; Neodymium Yag laser ; Vascular anastomosis ; Rat ; Tensile strength ; Histology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A comparative study was undertaken to investigate the application of a specially adapted microsurgical Neodymium Yag Laser system with a wavelength of 1,319 μm and a CO2 laser system for laser assisted microvascular end-to-end anastomosis (LAMA) of the rat femoral artery. Conventionally sutured anastomoses served as controls. Postoperative investigations included patency tests, light microscopy and tensile strength measurements. Both laser systems seem to be equally suitable for LAMA: The patency rates do not differ from those of sutured anstomoses and formation of microscopically small aneurysms occurred predominantly in control animals and only once in laser groups. The clamp time needed for LAMA was half the time that was needed for sutured anastomoses. Wound healing in all groups was similar with less fibrotic reactions and less foreign body granulomas in laser groups. At all intervals tensile strength was significantly higher for sutured anastomoses while differences between the CO2- and the ND: Yag-laser groups were not statistically significant. Potential applications in urology include microvascular anastomoses in erectile dysfunction, pediatric and reconstructive urology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00261970
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 127
    Electronic Resource
    Electronic Resource
    Failure to prolong rat renal allograft survival time by photochemical donor kidney pretreatment during hypothermic pulsatile kidney preservation (1988)
    Springer
    Urological research 16 (1988), S. 53-55 
    Details
    ISSN: 1434-0879
    Keywords: Renal transplantation ; Rat ; Ultraviolet irradiation ; PUVA ; Pulsatile perfusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Systemic photochemical pretreatment of a rat kidney donor with the photosensitizer 8-methoxypsoralen (8-MOP; 0.06 mg/kg intravenously, 10 min before graft removal) plus ex vivo longwave ultraviolet (UVA) irradiation of the kidney graft during simple hypothermic storage significantly prolonged survival time in allogeneic recipients. In contrast to these results, the present use of UVA irradiation during hypothermic pulsatile kidney perfusion using Euro-Collins® solution containing 8-MOP (0.06 mg/ml) did not prolong graft survival compared with untreated controls. Systemic application of 8-MOP to the kidney donor may be necessary for effective action of the combined photochemical treatment as a method of immunoalteration. The extended UVA irradiation time and the local use of 8-MOP in the preservation fluid had no effect on graft survival possibly because of inadequate tissue distribution of 8-MOP during both hypothermia and perfusion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00264629
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 128
    Electronic Resource
    Electronic Resource
    Comparison of long-term and short-term stretch on rat urinary bladder in vitro (1988)
    Springer
    Urological research 16 (1988), S. 277-280 
    Details
    ISSN: 1434-0879
    Keywords: Electrical stimulation ; Stretching ; Time factor ; Bladder strip ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Distension of the human urinary bladder often causes prolonged impairment of its function. To investigate the effects of the duration of stretch on bladder smooth muscle the active length-tension relation, electrically evoked, was described in rat detrusor strips during a short-term and a long-term stretch. The amplitude of active tension increased at first and then decreased abruptly at greater stretch lengths, the maximum being at muscle lengths 230–250% (100%=resting length) in both types of stretches. When the strips had been at maximum length (300%) for three hours the amplitude was significantly decreased during release as compared to the amplitude found during stretch to the maximum length at comparable lengths. If the strips were released immediately from the maximum length the amplitude responded in an opposite manner. Therefore we conclude that the duration of stretching of bladder smooth muscle significantly affects its mechanical activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00263635
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 129
    Electronic Resource
    Electronic Resource
    The influence of muscle interstitial volume on K+-induced heart rate drive in rats (1988)
    Springer
    European journal of applied physiology 57 (1988), S. 33-38 
    Details
    ISSN: 1439-6327
    Keywords: Interstitial volume ; Potassium concentration ; Heart rate ; Rat ; Exercise
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary During exercise heart rate is influenced by reflexogenic drives which are elicited by receptors situated in the interstitial space. Since the structure of interstitial tissue is complex (e.g. fixed negative charges of glycosaminoglycans), the situation in the immediate surrounding of the receptors might differ from the free fluid phases of blood or lymph in which the concentrations of stimulating substances are usually determined. Physiological variations of the interstitial structure may be due to changes in interstitial volume induced by exercise or the hydrostatic effects on body fluids. The objective of the present study was to investigate the effect of the interstitial volume on the relationship between heart rate and K+ stimuli applied through the muscle blood vessels. The calves of 12 male Wistar rats were artificially perfused and separated from the rest of the body with the sciatic nerve remaining intact. In these preparations the heart rate (HR) responses to low (4 mM) and high (8 mM) potassium concentrations were determined at different interstitial volumes. Expansion of the interstitial volume was obtained by reducing the colloid-osmotic pressure of the perfusate. The combination of intracellular oedema and mechanical limitation of total volume expansion (tapeing) was utilized to decrease the interstitial volume. When switching between the low and high potassium concentrations, significant heart rate responses could be observed only with reduced interstitial volume. It is suggested that the interstitial structure surrounding the muscular receptors modifies the relationship between heart rate response and the K+ stimuli determined in blood or lymph.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00691234
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 130
    Electronic Resource
    Electronic Resource
    Comparison of MIBG and monoamines uptake mechanisms: Pharmacological animal and blood platelets studies (1988)
    Springer
    European journal of nuclear medicine 14 (1988), S. 341-344 
    Details
    ISSN: 1619-7089
    Keywords: MIBG ; Monoamine uptake ; Blood platelets ; Rat ; 6OH-DA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The uptake of MIBG, a scintigraphic agent widely used in the detection of APUD tumors, was studied with a pharmacological approach on an in vitro and an in vivo models. MIBG as well as norepinephrine (NE) was taken up by human blood platelets, a model for presynaptic nerve endings amine uptake, with a thermodependant mechanism. MIBG and NE uptake was inhibited by desimipramine and reserpine. However, MIBG but not NE uptake was inhibited by fluvoxamine, a serotonin (5HT) uptake inhibitor. This suggests that MIBG is a NE and also a 5HT uptake tracer which involves uptake one and vesicular storage mechanisms. In rats treated with 6-hydroxydopamine to induced a chemical sympathectomy, we observed an inhibition of uptake similar for MIBG and NE in the heart, the salivary glands and the spleen, but no effect was observed in the liver. Some clinical inferences to best investigate specific monoamine uptake are drawn from these results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00254380
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 131
    Electronic Resource
    Electronic Resource
    Binding of intravenously injected antibodies against laminin to developing and mature endocrine glands (1988)
    Springer
    Cell & tissue research 251 (1988), S. 171-181 
    Details
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Basal lamina ; Laminin ; Anterior pituitary gland ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary To determine whether circulating antibodies against laminin can bind in vivo to basement membranes within endocrine glands, affinity-purified sheep or rabbit anti-laminin IgG was intravenously injected into rats. One to five hours after injection, anti-laminin IgG was bound to all basement membranes of adrenal and anterior pituitary glands of mature as well as 2-day-old newborn rats as shown by immunofluorescence microscopy. After the injection of anti-laminin conjugated directly to horseradish peroxidase (HRP), HRP reaction product was also present throughout adrenal and pituitary basement membranes in mature and immature glands 1–5 h post-injection. Ultrathin Lowicryl sections from rats that received unconjugated rabbit anti-laminin IgG 1 h prior to fixation with paraformaldehyde were labeled directly with anti-rabbit IgG-colloidal gold. In these cases, gold also bound specifically over the lamina densa and lamina rara. When adrenal or pituitary glands from mature rats were examined by immunofluorescence 1 week after the injection of sheep anti-laminin IgG, the patterns and amounts of bound sheep IgG were indistinguishable from those observed 1 h after injection. In contrast, significantly less fluorescence was present in glands from 7-day-old rat pups that had received anti-laminin IgG 5 days earlier. In addition, when anti-laminin IgG-HRP was injected into newborns and glands were fixed 5 days later, lengths of labeled endothelial and epithelial basement membranes were often interspersed with unlabeled lengths in zones of cellular proliferation in the outer adrenal cortex and throughout the pituitary gland. These results indicated that unlabeled basement membranes in these regions were probably assembled after the injection of anti-laminin IgG, which would also explain diminished labeling of basement membranes in these animals. Despite the continued presence of heterologous anti-laminin IgG within endocrine basement membranes, however, rat IgG, rat C3, inflammatory cells, or histologic abnormalities were observed in neither newborn nor adult glands under the conditions examined here. Sections from rats injected with control IgG or control IgG-HRP were entirely negative by immunofluorescence, immunoperoxidase, and immunogold techniques. We therefore conclude that (1) apparently large amounts of circulating anti-laminin IgG can bind to adrenal and pituitary basement membranes, and (2) at least some of these basement membranes are assembled during development by progressive splicing of newly synthesized matrix into that already present.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215462
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 132
    Electronic Resource
    Electronic Resource
    Pathway of nerves with vasoactive intestinal polypeptide-like immunoreactivity to the major cerebral arteries of the rat (1988)
    Springer
    Cell & tissue research 251 (1988), S. 275-280 
    Details
    ISSN: 1432-0878
    Keywords: Cerebral arteries ; Vasoactive intestinal polypeptide ; Vascular innervation ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pathway of nerves with vasoactive intestinal polypeptide(VIP)-like immunoreactivity to the major cerebral arteries was studied in rats by means of the indirect immunofluorescent method. The fibers are densely distributed in the ethmoidal nerves and in the adventitia of both the external and internal ethmoidal arteries. Section of both ethmoidal nerves and external ethmoidal arteries before they enter the cranial cavity induced a marked reduction of VIP-like immunoreactive fibers in the walls of the vessels of the circle of Willis and its major branches. However, section of the external ethmoidal artery alone did not result in visible changes of the nerves around major cerebral arteries. The present study suggests that VIP-like immunoreactive fibers surrounding major cerebral arteries of the rat arise from fibers in the ethmoidal nerve showing immunoreactivity to VIP.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215834
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 133
    Electronic Resource
    Electronic Resource
    Morphology of smooth muscle cells in the rat thoracic duct (1988)
    Springer
    Cell & tissue research 251 (1988), S. 243-248 
    Details
    ISSN: 1432-0878
    Keywords: Thoracic duct ; Smooth muscle cell ; Ultrastructure ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The three-dimensional cytoarchitecture and ultrastructure of the smooth muscle cells in the wall of the rat thoracic duct were investigated by scanning and transmission electron microscopy. The muscle layer basically consists of a single layer of circularly arranged cells. The smooth muscle cell is fusiform or ribbon-like in shape, as in veins or venules with a similar or smaller diameter. Connections by spinous processes are observed between adjacent muscle cells along their length. Spot-like membrane contacts frequently occur in areas where facing membranes are closely apposed. These are thought to be gap junctions and may be responsible for electrical coupling and mechanical attachment. Large invaginations arranged regularly in rows on the surface of the smooth muscle cells can be observed. These invaginations are closely associated with a flattened sarcoplasmic reticulum, and caveolae tend to open into the invaginations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215831
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 134
    Electronic Resource
    Electronic Resource
    Lymphocyte number and distribution in the rat uterine epithelium during estrous cycle and early pregnancy (1988)
    Springer
    Cell & tissue research 253 (1988), S. 241-244 
    Details
    ISSN: 1432-0878
    Keywords: Uterus ; Intraepithelial lymphocytes ; Estrous cycle ; Early pregnancy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The number of intraepithelial lymphocytes (IEL) in the luminal and glandular epithelium of the uterus of virgin rats was analysed in diestrus, proestrus and estrus, and in nulliparous rats on days 5, 7 and 9 of pregnancy. IEL number was calculated either with respect to the number of epithelial cells or to the length of epithelium section. It was found that in diestrus, the number of IEL was, on average, 3.7 per 100 luminal epithelial cells or 6.7 per 1 mm of epithelium section, whereas in proestrus, it decreased to 0.9 and 1.2 IEL, respectively. On day 5 of pregnancy (before implantation) the number of IEL decreased further to 0.45 per 100 luminal epithelial cells or 0.9 per 1 mm of epithelium. On days 7 and 9 of pregnancy, IEL number further decreased in implantation sites, whereas in interimplantation sites it remained at the level calculated for day 5 of pregnancy. The population of uterine IEL consisted of small (82–99%) and large (1–18%) lymphocytes. In all stages of the estrous cycle, IEL occurred with a frequency of 68–87% in the basal region, 8–20% in the middle region and 4–12% in the apical region of the luminal epithelium width.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221759
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 135
    Electronic Resource
    Electronic Resource
    Evidence for neuroendocrine regulation of preadipocyte proliferation and differentiation (1988)
    Springer
    Cell & tissue research 251 (1988), S. 65-70 
    Details
    ISSN: 1432-0878
    Keywords: Adipose tissue ; Cell proliferation ; Cell differentiation ; Histochemistry ; Swine ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cells in fetal adipose tissue and cells in vitro are characterized by rapid proliferation. Serum factors have been shown to be important for the rapid proliferation of cells in vitro. The present experiment was performed to determine if neuroendocrine regulatory mechanisms of the fetus can influence the actions of serum factors on preadipocyte proliferation and differentiation in vitro. Sera were obtained from decapitated fetal pigs and intact littermates during gestation. Sera were tested for their effects on primary cultures of preadipocytes and stromalvascular cells derived from inguinal adipose tissue of young Sprague-Dawley rats. Coverslip cultures were used for histochemical analysis of enzymes after 12 days of incubation with test media. Analysis of growth curves produced from sequential [3H]-thymidine labeling indicated that fetal age influences rates of proliferation. Sera from decapitated fetal pigs specifically reduced the number of proliferating preadipocytes in culture. Sera from decapitated fetal pigs induced a minimum of 50% less differentiation of sn-glycerol-3-phosphate dehydrogenase activity than sera from intact pigs at all fetal ages. Histochemical staining for enzymes of differentiating preadipocytes was also reduced in cultures incubated with sera from decapitated fetal pigs in comparison to sera from intact pigs. The present study has demonstrated that the in vivo effect of decapitation on fetal adipose tissue development is a consequence of alterations in systemic factors present in serum in response to removal of central regulation by the hypothalamic-pituitary axis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215448
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 136
    Electronic Resource
    Electronic Resource
    The lattice arrangement of the collagen fibres in the submucosa of the rat small intestine: scanning electron microscopy (1988)
    Springer
    Cell & tissue research 251 (1988), S. 117-121 
    Details
    ISSN: 1432-0878
    Keywords: Collagen ; Submucosa ; Intestine ; Scanning electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The three-dimensional architecture of the submucosal collagen fibres of the rat (3 weeks old) small intestine was examined by scanning electron microscopy using a selective microdissection method. The main framework of the submucosa was composed of two arrays of collagen fibre bundles running diagonally around the intestinal wall, one set in a clockwise direction, the other counterclockwise. These fibre bundles were about 5 μm in diameter and were oriented at a range of angle ± 30°–50° to the longitudinal axis of the intestine. With the advantage of the SEM observation it was demonstrated that these fibres in different arrays did not constitute two separate layers but interwove to form a unified lattice sheet. An irregular network of fine collagen fibrils over the main framework was also seen. The significance of their arrangement is discussed with respect to the skeletal function of the submucosa in the intestine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215455
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 137
    Electronic Resource
    Electronic Resource
    Adhesion, proliferation, and adipogenesis in primary rat cell cultures: effects of collagenous substrata, fibronectin, and serum (1988)
    Springer
    Cell & tissue research 251 (1988), S. 123-128 
    Details
    ISSN: 1432-0878
    Keywords: Adipocyte ; Primary culture ; Collagen ; Fibronectin ; Serum ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of collagenous substrata, fibronectin, and fetal bovine serum on the adhesion, proliferation, and adipogenesis of rat stromal-vascular cells are reported. There was no effect on initial stromal-vascular cell-attachment by fetal bovine serum or fibronectin. The number of cells attached to a hydrated collagen-gel was almost twice (P〈0.04) the number attached to dried collagen-gel or dried denatured collagen-gel. Total number of cells after 5 days in culture was similar among the collagenous substrata and among the treatments with or without fibronectin in the growth media. Total number of cells increased significantly (P〈0.02) with 10% FBS. Adipocytic formation was inhibited by hydrated collagen-gel (P〈0.02) compared to dried collagen-gel or dried, denatured collagenous substrata. An interaction occurred between dried, denatured gel and fetal bovine serum so that total formation of adipocytes increased by increasing the level of fetal bovine serum (P〈0.07). Adipocytic formation was inhibited by hydrated collagen-gel at all levels of fetal bovine serum. The percentage of cells that converted to adipocytes was significantly lower (P〈0.01) on hydrated collagen-gel compared to dried, denatured or dried collagen-gel. Percentage of conversion was not significantly different among levels of fetal bovine serum, although this percentage increased as fetal bovine serum level increased. Adipocytic conversion was not different between fibronectin-treated or untreated cells. Morphology of stromal vascular cells was similar on dried collagen and dried, denatured collagen-gel, but tended to remain bipolar on hydrated collagen-gel. These studies indicate that fetal bovine serum in combination with the extracellular matrix (dried, denatured collagen) increased the differentiation of rat stromal-vascular cells into adipocytes, and that hydrated collagen inhibited differentiation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215456
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 138
    Electronic Resource
    Electronic Resource
    Fine-structural localization of neuropeptide tyrosine (NPY)-like immunoreactivity in the neuronal somata of colchicine-pretreated celiac ganglia of rats (1988)
    Springer
    Cell & tissue research 251 (1988), S. 221-224 
    Details
    ISSN: 1432-0878
    Keywords: Neuropeptide ; Intracellular localization ; Sympathetic ganglia ; Colchicine ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In colchicine-pretreated cells of sympathetic ganglia, intensely NPY-immunoreactive material was localized within vacuoles and vesicles of the disorganized, widely dispersed Golgi apparatus. Intensely positive large granular vesicles, which are known to be one of major storage sites of various peptides in the autonomic nerve endings, were essentially unobserved in the perikaryal cytoplasm. The present finding provides evidence that one pool of NPY-like immunoreactivity is localized in the Golgi apparatus of colchicine-pretreated as well as normal sympathetic ganglion cells. It is also clear that visualization of NPY-immunoreactive somata by colchicine-pretreatment in the sympathetic ganglia is due to the accumulation of the neuropeptide in the disorganized Golgi stacks instead of increased amount of the large granular vesicles containing NPY.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215468
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 139
    Electronic Resource
    Electronic Resource
    Masthead (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988) 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110101
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 140
    Electronic Resource
    Electronic Resource
    Axial pressure profile in circulating fluidized beds (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 11-17 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Design and operation of a circulating fluidized bed requires the knowledge of fluid mechanics. According to heat and mass transfer as well as chemical reactions, the effect of the set superficial gas velocity on the axial pressure profile is of particular interest. The axial pressure profile was measured for a variety of solids, as a function of the superficial gas velocity, in a cylindrical circulating fluidized bed with an inner diameter of 0.19 m and an overall height of 11.5 m. Depending on the solids content and superficial gas velocity, two or one sections can be observed in the plant where the pressure gradient is constant. A pressure profile with one pressure gradient exists only at high gas velocities, so long as the acceleration pressure drop immediately above the gas distributor is negligible. Comparison of measured pressure drops in circulating fluidized beds with those measured in vertical pneumatic conveying led to a state diagram for vertical gas-solid flows. The operation behaviour of different types of circulating fluidized bed plants can be explained with the aid of this diagram.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110103
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 141
    Electronic Resource
    Electronic Resource
    Engineering aspects and applications of crossflow microfiltration (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 17-25 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Crossflow microfiltration (CMF) is a pressure driven membrane process for the separation of suspended microparticles, bacteria and emulsion droplets. The fluid to be filtered flows in parallel to the membrane surface and restricts the formation of a filter cake. This contribution explains the basic process characteristics and the combination of the crossflow technique with other membrane cleaning methods (periodic backflushing, chemical cleaning). Special attention is paid to the influence of different process parameters on the flux through the membrane. The principle of plant design and different operation modes are described. Engineering aspects such as hydrodynamics, energy requirement and selection of construction materials are discussed in some detail.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110104
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 142
    Electronic Resource
    Electronic Resource
    Mass transfer contributions of solid particles to gas permeation in viscous laminar tube flow (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 25-31 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: While two- and multiphase flows find more and more application in chemical engineering practice, and the demand for theoretical information about mass and heat transfer processes in such systems is increasing, such data or at least experimental results which could be generalized are still lacking. The following pages are concerned with mass transfer in laminar suspension tube flows normal to the main direction of flow due to the individual motions of small, inert spherical particles. On the basis of a large number of experimental data, an interpretation is attempted of the role of nearly neutrally-buoyant particles in mass transfer enhancement, and a model for a semi-empirical description is suggested. The experimental arrangement uses the mass transfer of carbon dioxide in laminar flow of salt water during the process of gas permeation through a permeable membrane tube wall.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110105
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 143
    Electronic Resource
    Electronic Resource
    Heat transfer between particle beds and submerged surfacesPaper presented by O. Molerus at the “Jahrestreffen der Verfahrens-Ingenierue”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 126-138 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Theoretical modelling of heat transfer to particle beds comprises two sequential steps: transfer from the heating surface to contacting particles followed by transfer to the interior of the bed. Two different limiting case can be formulated for the second step: unmixed and homogeneously mixed bed. In the case, heat is transferred gradually via a repeated sequence of heat transfer in the gap between adjacent particles and conduction in the particulate material. In the second case, heat is transferred to the interior of the bed by mixing of particles which have previously attained the temperature of the heating surface. On the other hand, the mixing motion maintains a homogeneous lower temperature throughout the bed. Theory predicts a significant and easily measurable difference in the behaviour of heat transfer coefficients for the two regimes at long contact times t: unmixed beds ∝ \documentclass{article}\pagestyle{empty}\begin{document}$$ \sqrt t $$\end{document} and homogeneously mixed beds ∝ 1/t. For short times t, both regimes show the same behaviour, namely of t.From a theoretical standpoint, it makes sense to differentiate further between the behaviour patterns of unmixed beds: at long times t, instantaneous heat transfer coefficients are independent of heat transfer form the heating surface to adjacent particles. Comparison with experimental result from literature shows that the derived models, which are consistent, are suitable for describing the heat transfer from submerged surfaces to unmixed and mixed beds of particles.
    Additional Material: 24 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110118
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 144
    Electronic Resource
    Electronic Resource
    Scale-up of bioreactors for fermentation of mammalian cell cultures with special reference to oxygen supply and microcarrier mixingPaper presentet by J. Vorlop at the “Jahrestreffen der Verfahrensingenieure”, September 17 to 19, 1986 in Strasbourg (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 171-178 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The increasing demand for products from mammalian cells has prompted the authors to develop a new type of bioreactor. Its significant features include the supply of oxygen, homogeneous distribution of microcarrier suspensions and process control. Media with high protein contents, required for mammalian cell cultures tend to generate foam. This causes the flotation of solid particles. The reactor was equipped with a system of porous hydrophobic Accurel hollow fibre membranes in order to prevent the formation of bubbles. The membrane is coiled in the form of a basket, or fixed on several carriers. If the liquid pressure is higher than that of the gas phase inside the membrane, a bubble - free oxygen supply to the culture broth can be achieved. The problem of axial mixing of microcarier suspensions was solved by the use of a spiral agitator, attached underneath the aeration system at the bottom of the reactor. The combined aeration and mixing system, which is driven by an eccentric motor, undergoes a tumbling motion. Sufficiently homogeneous suspensions are produced in this system at low membrane velocities, i.e. in presence of low shear forces.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110123
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 145
    Electronic Resource
    Electronic Resource
    Organosolv delignification of southern pine - an alternative pulping process (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 195-199 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Aqueous ethylenediamine-ethanol-anthraquinone (EDA-EtOH-AQ) pulping of Southern Yellow Pine was studied for lignin removal and pulp yield. Temperature, time and ethylenediamine concentration in the solvent solution were studied and equations for lignin content and lignin-free yield were developed. Lignin content is decreased by an increase of temperature, time or EDA concentration. Lignin-free yield of pulp decreased with an increase in temperature or time, but increased with increasing EDA concentration. Overall, the solvent is selective, that is, large quantities of lignin are removed while the retention of cellulose remains high.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110126
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 146
    Electronic Resource
    Electronic Resource
    Consistent scale-up procedure for the power consumption in agitated non-newtonian fluids (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 199-205 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: It is shown how a consistent scale-up rule for the power consumption in agitated non-Newtonian liquids can be obtained. The new approach is based on the concept of including the real liquid in a set of liquids with similar rheological properties and of using, in a small scale laboratory system, a suitable member of that set instead of the original liquid. Considerations of similarity lead to simple unique selection rules for the actual test liquid and for the stirrer speed in the laboratory experiment as well as to a prediction of the power requirement in the real system. The theory is tested experimentally by means of different aqueous polyacrylamide solutions. The results are compared with predictions, according to Metzner and Otto as well as Rieger and Novák.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110127
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 147
    Electronic Resource
    Electronic Resource
    Bubble column research in Japan (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 205-212 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Many experimental studies on the bubble column have been reported by Japanese researchers since around 1960. They include studies of bubble behaviour, bubble size distribution, transition from the homogeneous bubbly flow regime to the heterogeneous liquid circulation regime, liquid velocity distribution, longitudinal liquid mixing, hydrodynamic modelling, the gas holdup, and the volumetric coefficient of gas-liquid mass tranfer kLa. Studies covered various modified bubble columns, such as the airlift reactor with an external or internal loop, the packed bubble column, and others. Performance of three-phase bubble columns, which deal with suspensions or emulsions, and their use as bioreactors or chemical reactors were also studied.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110128
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 148
    Electronic Resource
    Electronic Resource
    A model-based control system for a distillation columnPaper presented by F. F. Rhiel at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 188-194 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A control concept which includes an adaptive multivariable control algorithm and an observer model has been put into practice in the operation of a distillation column which separates water from a solvent. The model yields predictions of solvent concentration in the waste water which forms the top product. Early detection of disturbances permits an adjustment of the process in time. This has resulted in an exceptionally smooth operation of the column, with a drastic reduction in solvent concentration fluctuations, observed with conventional control technology. Since the only measurements required are pressure, temperature and the rate of flow, this control system is largely free from disturbances. In addition to considerably reducing the burden on operating personnel, use of this control system has lowered the costs of waste water treatment, solvent losses, analysis expenditure and energy consumption.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110125
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 149
    Electronic Resource
    Electronic Resource
    Development of design charts for fixed-bed adsorptionPaper presented by W. Otten at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, Spetember 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 289-297 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A mathematical model of the dynamic behaviour of non-isothermal fixed-bed adsorbers has been developed which takes into account the various mass and heat transfer resistances. Comparison of experimental and simulated results confirms that the model can predict the adsorption and desorption breakthrough curves of an adiabatically operated column, using only equilibrium data and tortuosity factors obtained from single pellet experiments. A simplified model with a reduced number of parameters was derived by investigation of the dimensionless transfer parameters under industrial conditions. It becomes evident that the main transfer mechanisms are convective heat and mass transfer in the bulk flow and diffusion within the pores of the particle. Dimensionless effluent concentration is expresses in terms of dimensionless time, a transport parameter, a non-isothermal parameter, the adsorption equilibrium and the inlet and initial concentrations and temperatures in the simplified model. For a chosen system of adsorbate and adsorbent, design charts can be developed by computer simulation, to determine graphically the breakthrough time as a function of significant process parameters, i.e. the dimensionless transfer parameter and the feed concentration.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110138
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 150
    Electronic Resource
    Electronic Resource
    The role of energy dissipation in contacting and mixing devicesPresented in memory of Professor Otto Nagel, at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 276-287 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The aim of the present paper is the discussion of the relevance of power dissipation as a criterion for the understanding and prediction of transfer and mixing efficiencies in contactors and chemical reactors. After reviewing the approach of Le Goff to the energetic efficiency of exchangers, based on the deviations from Chilton-Colburn analogy, the following processes are studied: mass transfer between a flowing fluid and a reactive solid surface, transfer to a fixed object in a stirred vessel, macro- and micromixing of miscible fluids, and mass transfer in fluid-fluid contractors (especially gas-liquid reactors). It is concluded from the various examples that a direct relationship between the dissipated power and intensity of transfer or mixing can be established only under the two following conditions: local values must be considered at the point where the actual transfer and mixing occur, and not average values over the whole device, and power dissipation must be coupled to transfer or mixing and appear physically as the driving force of the process.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110137
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 151
    Electronic Resource
    Electronic Resource
    Subcooled boiling heat transfer to R 12 in an annular vertical channel (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 320-327 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Detailed knowledge of the physical phenomena involved in subcooled boiling is of great importance for the design of liquid-cooled heat generating systems with high heat fluxes. Experimental heat transfer data were obtained for forced convective boiling of dichloro-difluoroethane (R 12). The flow is circulated upwards through a concentric annular vertical channel. The inner and outer diameters of the annulus are 0.016 m and 0.03 m respectively. The reduced pressures studied were 0.24 ≤ p/pcrit ≤ 0.8, inlet subcooling varied from 10 to 75 K and mass fluxes from 500 to 3000 kg/m2s, which corresponds to Re numbers from 30000 to 300000. The experiments, described in this study, demonstrate that liquid fluorocarbons show certain unusual boiling characteristics in the subcooled flow, such as hysteresis of the boiling curve. These characteristics are attributed to the properties of the fluid, mainly the Pr number and the very low surface tension. The pronounced boiling curve hysteresis can be explained by the fact that large nucleation sites may have been flooded prior to incipient boiling. A dimensionless regression formula is presented which predicts the onset of subcooled boiling as a function of reduced pressure (p/pcrit), Boiling-(Bo), Reynolds-(Re), and a modified Jacob number (Ja), over the whole range of parameters studied, with a good accuracy, including water data from literature.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110142
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 152
    Electronic Resource
    Electronic Resource
    Mass transfer behaviour of gas-liquid jet loop reactorsPaper presented by M. Geisendörfer at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, September 30 to October 2, 1987.Dedicated to Professor Dr. Horst Langemann on the occasion of his sixtieth birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 306-311 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A special type of jet loop reactor (JLR), designed for continuous operation and short residence times was investigated with regard to its mass transfer behaviour, described by the volumetric mass transfer coefficient kLa. The jet stream and superficial gas velocities are varied in two JLRs of different sizes, equipped with different nozzles. Fully desalinated water, 0.08 molar NaCI solution and solutions of different concentration of carboxymethyl cellulose (CMC) are used as the liquid phase. A steady-state physical method is employed to determine kLa: air oxygen is purged from the liquid phase by gaseous nitrogen. The measurements show that the reactor is characterized by high power density and high mass transfer performance. No limit of mass transfer capacity was observed in the chosen ranges of volumetric gas and liquid flow rates, i.e. at a given jet stream velocity, the relationship between kLa and the superficial gas velocity is nearly linear. The investigations show that the mass transfer contributed by the jet stream largely depends on liquid phase composition.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110140
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 153
    Electronic Resource
    Electronic Resource
    Characteristics of solid suspensions in a bubble column without and with draft tubePaper presented by J. Heck at the “Jahrestreffen der Verfahrensingenieure”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 335-340 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In order to investigate the suspension behaviour of solid particles in bubble columns without and with draft tube, minimum gas velocities for generating and maintaining complete solid suspension were determined. Experiments were carried out in a bubble column with a diameter of 200 mm and a height of 2 500 mm. The bubble column could be equipped with a draft tube with a diameter of 120 mm and a length of 1 500 mm. The state of suspension was determined by measuring the hydrostatic pressure as a result of suspended solid particles with an inductive pressure gauge. Solid content εs, solid density ϱs, particle size dp, particle shape, particle size distribution, and solid wettability were varied. Furthermore measurements of integral gas holdup were carried out.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110144
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 154
    Electronic Resource
    Electronic Resource
    Modelling of multiphase detonations with drop disintegration - description of thermal detonations (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 327-334 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A model is presented which consists of steady-state and transient codes for the description of reacting multiphase flow fields, including hydrodynamic fragmentation of liquid drops in relative flows. An application of this model for the description of large scale melt-coolant interactions (thermal detonations) is described. A simulation of two-phase chemical detonations, especially those with hydrodynamic disintegration of liquid fuel drops in the reaction zone, is possible, in principle, within the framework of the modeling.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110143
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 155
    Electronic Resource
    Electronic Resource
    Modelling of a pressure swing adsorption process for oxygen enrichment with carbon molecular sievePaper presented by E. Richter at the “Jahrestreffen der Verfahrens Ingenieure”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 341-351 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Adsorptive separation of oxygen from nitrogen and argon is carried out during the desorption steps of a pressure swing adsorption (PSA) process which uses carbon molecular sieves developed by Bergbau-Forschung GmbH. The adsorption isotherms of the three main components of air are very similar. On account of the pore size distribution of CMSN2, the diffusion coefficient of oxygen is more than eight times those of nitrogen and argon so that air separation occurs by adsorption kinetics. Experimental results for the individual steps and cyclic operation of the PSA process are presented and compared with the predictions of an isothermal plug-flow model. Adsorption rate is represented by a linear driving force equation. If the diffusion coefficients are adapted separately to every step, a good agreement is observed between the model calculations and experimental results.
    Additional Material: 22 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110145
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 156
    Electronic Resource
    Electronic Resource
    The importance of corrosion prevention for the safety of chemical plants (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 359-365 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: One of the most important tasks to eliminate dangers in chemical plants is the prevention of corrosion. This implies the provision of safe enclosures and reaction spaces for the substances to be processed. The present contribution deals with the procedure in the selection of materials for equipment exposed to corrosion and stresses the difficulties connected with the elimination of local corrosion. The relevance of prevention of crack forming corrosion processes is emphasized. Problems to be solved in order to obtain results from investigations, suitable for a safe application of a materials under practical conditions, are indicated.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110147
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 157
    Electronic Resource
    Electronic Resource
    Modelling of activated carbon desorption by a circulated inert gasPaper presented at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, September 30 to October 2, 1987 (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 352-358 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The adsorption solvent recovery process, known as Recursorb which involves desorption and cooling steps by a circulated inert gas, is analyzed in detail on the basis of equilibrium theory. Employing the method of characteristics, the model is solved for each step of the overall process. The estimations confirm that the process performance with respect to final gas purity, activated carbon useful capacity and operation times depends on condenser and heater temperatures. Simple expressions are derived for the calculation of adsorption, desorption and cooling times.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110146
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 158
    Electronic Resource
    Electronic Resource
    Decoking of fixed-bed catalytic reactorsDedicated to Prof. Dr. Hanns Hofmann at the ocassion of his 65th birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 367-375 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A mathematical model for the description of the non-steady state process of decoking of a fixed bed catalytic reactor is presented. The relevant dimensionless groups are identified and their influence on the process discussed. Appropriate relationships are given for the estimation of the maximum temperature in the bed. Methods of monitoring the process and of controlling it in the case of unknown or variable coke contents are explained.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110148
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 159
    Electronic Resource
    Electronic Resource
    Model discrimination and parameter estimation in the kinetic study of methanol synthesisDedicated to Professor Dr. Hanns Hofmann on the occasion of his 65th birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 375-383 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The new model discrimination method is based on the correlation coefficient test of experimental data sets for different reactions, without requiring a prior parameter estimation. The new parameter estimation method reduces by n the number of dimensions to be tested, compared to the classical method where n is the number of independent reactions in the system. This has reduced the computation time for most complex reactions to a level, comparable to that needed for single reactions. The example used is the kinetic study of methanol synthesis in which the formation rates of methanol, methane, ethanol and ethane are considered. Two adequately accurate models were obtained from an extensive range of plausible models by using the new model discrimination and parameter estimation method with a relatively small computation effort.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110149
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 160
    Electronic Resource
    Electronic Resource
    Evaporation and pervaporation of a binary mixture from an inert carrier liquidDedicated to Professor Hanns Hofmann on the occasion of his 65th birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 384-391 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Bench-Scale experiments were carried out with the ternary mixture 2-propanol/water/glycerol. In a cylindrical vessel, the stirred and thermostated liquid was exposed to a preheated and either dry or humidified air stream. The mixture was evaporated either from a free surface or from the surface of a porous plate. On evaporating the mixture from a porous plate into a dry air stream, the less volatile component water escapes preferentially; in the case of evaporation from a free surface, water is retained in the mixture. In the former case, selectivity is liquid diffusion controlled, in the latter, the gas-side mass transfer and the thermodynamic equilibrium are the controlling mechanisms. On reducing the gas flow rate, the more volatile alcohol evaporates preferentially in both cases; the selectivity is controlled only by thermodynamic equilibrium. Humidification of the air stream with water vapour causes preferential evaporation of the alcohol at an increased rate. Furthermore, instabilities in the liquid boundary layer due to density gradients and surface tension effects may affect the selectivity of evaporation. Experimental results show that the selectivity of evaporation can be manipulated by choosing appropriate evaporation conditions. The theory, which applies the generalized Stefan-Maxwell equations to diffusion in the liquid, can describe these effects.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110150
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 161
    Electronic Resource
    Electronic Resource
    Remarks upon the modelling of heterogeneous catalytic reactors - the single fluid-solid casesDedicated to Professor Hanns Hofmann on the occasion of his 65the birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 425-431 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: To our benefit, the modelling of fluid-solid catalyzed reaction-reactor systems has long been the keen concern of Hanns Paul Hofmann. In the light of his instruction we remark upon key aspects of modelling for the (a) fixed bed (b) fluid bed and (c) moving bed/transport line reactors. There emerges from such analyses a properly renewed awareness of the need for a more sophisticated respect for reliable physical-chemical data. As Hanns has taught us, our models are no btter than our data.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110154
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 162
    Electronic Resource
    Electronic Resource
    Two-phase flow in porous mediaThe Orginal, shorter form of this paper was presented by the author, as an invited speaker, at the Second Conferance of “Chemical Reaction Engineering” of the Engineering Foundation, March 8 to 13, 1987, Santa Barbara, California.Dedicated to Professor Dr. Hanns Hofmann on the ocassion of his 65th bithday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 407-424 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Two-phase flow in porous media depends on many factors, such as displacement vs steady two-phase flow, saturation, wettability conditions, wetting fluid vs non-wetting fluid is displacing, the capillary number, interfacial tension, viscosity ratio, pressure gradient, uniformly wetted vs mixed-wet pore surface, uniform vs distributed pore throats, small vs large pores, well-connected pores vs pores connected by small throats, etc. These parameters determine how the two fluids are distributed in the pores, e.g. whether they flow in seperate channels or side-by-side in the same channels, either with both fluids being continous or only one fluid being continous and the other discontinuous. In displacement, the capillary number and the viscosity ratio determine whether the displacement front is sharp, or if there is either capillary or viscous fingering.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110153
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 163
    Electronic Resource
    Electronic Resource
    Kinetic investigation of methacrylic acid synthesis on hetropoly-compoundsDedicated to Professor Dr. Hanns Hofmann on the ocassion of his 65th bithday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 392-402 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The kinetics of heterogeneously catalyzed methacrylic acid synthesis from isobutyric acid has been investigated. Initial catalyst screening pointed to 10-molybdo-2-vanado-phosphoric acid and its Cs-salts as the most promising catalysts. A model describing the reaction behaviour of all the different hetropoly-compounds used in this work was developed. A relationship was found between model parameters and composition of different catalysts. First insight was gained into the catalyst deactivation phenomena. Deactivation appears to be caused mainly by loss of molybdenum with simultaneous collapse of the Keggin structure.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110151
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 164
    Electronic Resource
    Electronic Resource
    A new regenerable process for the recovery of SO2Dedicated to Professor Hanns Hofmann on the occasion of his 65th birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 402-407 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Increasing demand for regenerable processes with SO2 recovery is to be expected. Advantages and limitations of the earlier developed citrate and adipate absorption/ steam stripping process are compared with those of the Wellman-Lord (sulphite) process. On the basis of comprehensive laboratory studies, a new process is proposed which supplements the citrate and adipate process. In this new process, the absorbent is a concentrated sodium phosphate buffer and the loaded buffer is regenerated by evaporation. The main buffer component is Na2HPO4, but NaH2PO4 is added in order to obtain a more complete stripping of SO2 during regeneration. The new process promises excellent absorption properties for SO2 with extremely low oxidation losses, regeneration with few incrustation problems and appreciable energy savings.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110152
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 165
    Electronic Resource
    Electronic Resource
    Derivation, selection, evaluation and use of asymptotes (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 63-72 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Asymptotes are known to be useful, but their potential in interpreting and correlating chemical and physical behaviour is seldom exploited fully. The derivation and selection of asymptotes for particular as well as limiting cases is described. The evaluation of the range of validity and applicability, if any, of asymptotes is also considered. Asymptotes are shown to be uniquely useful in the identification of groupings of variables which minimize parameteric variations, as upper and lower bounds, as trial functions in the method of weighted residuals, and most especially as components of correlating equations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110110
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 166
    Electronic Resource
    Electronic Resource
    A robust pole-placement self-tuning controller for chemical process control: Theoretical studies and simulation (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 57-62 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A single variable pole-placement self-tuning controller (PPSTC) is used to simulate examples typical of chemical processes; i.e., open-loop stable, unstable, and unstable non-minimum phase systems with unknown varying process dead time. The PPSTC is shown to be effective in each case. Set-point tracking and rejection of randomly occurring deterministic disturbances for all three types of processes are achieved. Simultaneous estimation of process parameters and process time delay is realized by using a recursive extended least squares method.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110109
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 167
    Electronic Resource
    Electronic Resource
    The influence of stress and attrition on crystal size distributionPaper presented at the Annual Meeting of German Chemical Engineers 1986, September 17 to 19, in Strasbourg.Dedicated to Prof. Dr.-Ing. Rolf Lacmann on the occasion of his 60th birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 40-49 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An important parameter influencing the crystal size distribution in mass crystallization from solution is the mechanical stress exerted on crystals in the crystallizer. This contribution presents the study of the influence of mechanical stress and attrition of the system potassium nitrate-water in an FC-crystallizer and in various draft-tube crystallizers, fitted with different types of impellers. The intensity of stress is a newly defined variable which is used to describe the level of stress in crystallizers. The reduction of crystal size by attrition is described by the linear attrition rate. The influence of impeller design and crystal hold-up on crystal size distribution and scale-up rules is discussed.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110107
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 168
    Electronic Resource
    Electronic Resource
    Experimental results from a plate-column wet scrubber with gas-atomized sprayPaper presented at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 73-79 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A pilot wet scrubber was examined experimentally. It is constructed like a plate column. Its plates are designed to set the gas into a whirling motion with tangential velocities of up to 25 m/s and to ensure a uniform distribution of the liquid throughout the gas flow. Particles suspended in the waste gas are collected by gas-atomized droplets to yield cut diameters between one and two microns. Energy consumption is lower than in the case of other scrubbers. The scrubbing mechanisms are analyzed by examining the measured pressure drops. Finally, methods of determining the collection efficiency are discussed and an empirical approach to its calculation is presented.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110111
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 169
    Electronic Resource
    Electronic Resource
    Attrition and secondary nucleation in crystallizers (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 80-88 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The mean crystal size of coarse crystalline products is determined by secondary nucleation and crystal growth. Secondary unclei are mainly produced by contacts of crystals with parts of the crystallizer or with other crystals. As a consequence, attrition effects are very important. In this paper, a model is proposed in order to calculate the attrition rate of crystals, depending on the physical properties of the crystalline product, the geometry of the crystallizer and on the operating conditions such as the stirrer speed or the suspension density. The effective rate of secondary nucleation can be expressed in terms of the attrition rate by introducing effective values for number and size of attrition particles. Finally, a scale-up criterion based on this model is derived. This criterion allows to predict effective rates of secondary nucleation and mean crystal sizes if data obtained in a laboratory crystallizer are available.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110112
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 170
    Electronic Resource
    Electronic Resource
    Effect of combustion air preheating on NOx emissions from gas burners in high-temperature industrial applicationsPresented by M. Flamme at the “Jahrestreffen der verfahrens-ingenieure”, strasbourg, september 17 to 19, 1986. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 104-112 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: NOx emissions from different commercial gas burners for metal heat treatment applications were measured for a research project of the Gaswärme-Institut. The burners, rated at up to 50 kW, were installed for the tests in a laboratory combustion chamber operated at temperatures of up to 1400°C. The air for combustion was preheated to maximum temperature of 600°C. Following the tests, the potentials of different NOx control techniques were investigated. Methods explored included staged combustion air injection, staged fuel injection and fuel gas injection into the flue for NOx reduction. The results showed that it is feasible to reduce the NOx content of flue gases by as much as 90%.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110115
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 171
    Electronic Resource
    Electronic Resource
    Theoretical and experimental study of sedimentation in vertical flow tanks (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 95-104 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Settling characteristics of four different suspensions were measured by batch settling tests (glass spheres in glycerol-water mixtures and CaCO3) and by continuous settling test in a bench-scale vertical flow tank (activated sludge and kaolin in water), including the measurement of solids concentrations inside the tank. The characteristics could be described by different correlation functions which now include all the information about the settling behaviour of ideal suspensions. Continuous settling experiments in a bench-scale vertical flow tank were carried out with the same four material systems. These results correspond with sufficient accuracy to those from the theory of limiting flux if the settling characteristics determined earlier are considered.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110114
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 172
    Electronic Resource
    Electronic Resource
    Thermal deactivation of heterogeneous catalyst, part 1. The theta-rule - a critical review (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 113-119 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Thermal deactivation can be described either by deactivation kinetics or by the isokinetic effect. The latter expression is used synonymously with the “compensation effect” and the “Theta-Rule”. An examination of the original literature shows that only the compensation effect is applicable to thermal deactivation but not the Theta-Rule. The introduction of the preparation temperature as a parameter of the compensation effect results in a “modified Theta-Rule”, which describes the experimental data and is proposed for the non-separable kinetics. The consequence of the observed deviations from the validity range of the Theta-Rule is that the activation energy cannot be used as a universal activity criterion.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110116
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 173
    Electronic Resource
    Electronic Resource
    The stability of crude oil residues and factors affecting their decomposition during mild thermal treatment (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 89-94 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A number of topped crude oil residues were subjected to mild thermal cracking in the temperature range between 613 and 673K at N2 pressure of one atmosphere. It was found that the thermal stability of the six topped crude oils decreased in the order Brent 〈 Piper 〈 Auk 〈 Saudi Arabian 〈 Romashkinskaya 〈 Tia Juana Pesado. This was measured in terms of light end production (C1-C5 hydrocarbons). The asphaltene, sulphur and metal (nickel and vanadium) contents were also determined. The production of light ends, exemplified by methane, was found to be related to the metal asphaltene content of the crude oils, but the sulphur content exerted a moderating influence upon the extent of cracking. Hence, metal asphaltenes, probably as metal porphyrins, catalyse cracking but the presence of sulphur reduces that catalytic activity and can inhibit cracking. If cracking of long chain hydrocarbons is to be minimized, metal asphaltenes should be removed (preferably) or reduced in concentration or poisoned, in order to decrease their catalytic activity.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110113
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 174
    Electronic Resource
    Electronic Resource
    Kinetic analysis of the oxidation of isobutyraldehyde in liquid phase (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 120-126 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The kinetics of non-catalytic as well as catalytic oxidation of Isobutyraldehyde has been investigated. Reaction rate equations for the formation of the main product isobutyric acid and of the side products acetone, CO and CO2 were derived. Kinetic parameters, namely the order of reaction, preexponential factor and activation energy were estimated by non-linear regression. The influence of selectivity and activity of the different type of catalysts employed was investigated quantitatively.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110117
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 175
    Electronic Resource
    Electronic Resource
    Relationship between residence time, fluid dynamics and efficiency in countercurrent flow equipmentPaper presented at AIChE Annual Meeting 1986, Miami Beach, Florida, USA (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 139-148 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The suitability of any item of equipment for a given thermal separation process cannot always be judged solely in the light of efficient and loading range data. In vacuum rectification, involving a large number of theoretical stages, the vapour pressure drop per transfer unit exerts a considerable effect on the energy consumption and thus largely governs the choice of column fittings. Furthermore, the pressure drop per transfer unit determines the temperature at the bottom of a rectification column and, hence, the suitability of the equipment for the separation of heat-sensitive products. It is also an important criterion for compressor requirements in absorption processes. Another factor of considerable importance in separating heat-sensitive mixtures by distillation is the time during which the product, particularly the liquid phase, is exposed to a given temperature in the column. Therefore, a standardized liquid residence time has been adopted to evaluate the systems in their entirely. This residence time depends on the hydrodynamic conditions in the column and is thus closely related to pressure drop and efficiency. Further important factors, which may decide the selection of column internals, are the specific volume and mass of the column. Based on theoretical considerations, a flow model is derived for describing the main loading range of countercurrent packed columns; the relationships between the above mentioned parameters are presented.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110119
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 176
    Electronic Resource
    Electronic Resource
    The significance of fly ash in wet-dry scrubbing of SO2 (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 298-305 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A bench scale flue gas desulphurization spray dry scrubbing unit was employed to study the effect of fly ash on the removal of SO2. The equipment consisted of a spray dryer with and ultrasonic nozzle for atomization and a pulse jet baghouse. The flue gas rate was 1500 lN/h (dry gas). Four fly ashes, originating from different countries were investigated. The alkalinity and reactivity of the fly ashes were determined in a pH-stat equipment. Pure fly ash removed SO2 in both the spray dryer and in the baghouse. An increase of humidity divided the fly ashes into two groups. The high calcium fly ash gave a considerably higher SO2 removal than the medium and low calcium fly ashes which showed similar SO2 removals. Fly ash did not enhance the removal of SO2 when added to a lime slurry because lime suppresses the dissolution of the alkali in the fly ashes. The pressure drop build-up in the fabric filter showed a strong dependence on material properties.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110139
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 177
    Electronic Resource
    Electronic Resource
    Less known behaviour of gas-solid reactions: The expanding core model in catalytic and non-catalytic systemsDedicated to Profeesor Dr. Hanns Hofmann on the Occasion of his 65th birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 438-447 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Gas-solid reactions cover a wide spectrum of industrial products. Over the years, many conceptual models have been developed to describe the progress of a gas-solid reaction starting outside the solid particle as well as that occurring throughout the particle. But the behaviour of a reaction, initiated inside the pellet, is less known. In this paper, a brief outline is given of this relatively rare but important mode of gas-solid reaction. The causes of this relatively less known behaviour and characteristic features of five typical systems displaying it are discussed.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110156
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 178
    Electronic Resource
    Electronic Resource
    A new appraisal of mass transfer processes in zeolites by transient methodsDedicated to Professor Dr. Hanns Hofmann on the occasion of his 65th birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 432-438 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Transient diffusion of inert gases into Zeolon 900 H, a zeolite of the mordenite type, was studied by the chromatographic method. Experiments were performed with argon and helium either as tracer or as carrier gas. The diffusion of argon was also studied in a carrier gas containing methanol at a low temperature (75°C, no reaction) and at higher temperatures (up to 130°C) when some dehydration of methanol to dimethyl ether takes place. The adsorption isotherm of argon is linear. In the absence of methanol, its penetration into microcrystals of zeolite is equally well represented either by an effective diffusion coefficient D′μ = 7.4 × 10-8exp(-2873/T)m2s-1 or by a mass transfer coefficient at the crystallite surface keμ = 1.9 × 10-4 exp(-1324/T) ms-1. A small amount of methanol in the carrier gas considerably slows down the transfer of argon (by a factor of 40 for D′μ and 550 for keμ) showing the “blocking” effect of adsorbed methanol. In addition, transient adsorption can no longer be accounted for by a single transfer time. The size distribution of microcrystals, determined from Scanning Electron Microscope photographs leads to a Transfer Time Distribution which account well for experimental breakthrough curves without any parameter fitting. This interpretation is supported by experiments under reaction conditions where transport of argon within crystallites increases faster with temperature than in the absence of reaction due to the transformation of methanol into dimethyl ether, which is less adsorbed and thus provides lesser hindrance to argon diffusion.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110155
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 179
    Electronic Resource
    Electronic Resource
    Hydrodynamic model of the urinary bladder derived from stepwise cystometry in the rat (1988)
    Springer
    Medical & biological engineering & computing 26 (1988), S. 267-270 
    Details
    ISSN: 1741-0444
    Keywords: Compliance ; Curve fitting ; Rat ; Stepwise cystometry ; Urinary bladder ; Viscoelasticity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The urinary bladder of the rat was examined by nearly ideal, unit step volume infusions. Spontaneous detrusor contractions occurred in vivo but ceased soon after death. A hydrodynamic model of the post mortem bladder wall was evaluated. Elastic properties were described by introducing two types of compliances; a dynamic compliance for fast response characteristics and a static compliance for the relaxed bladder wall. These compliances were easy to measure and found to vary with the degree of bladder expansion. The influence of viscosity was well described by a model with two relaxation time constants and was the optimal model in almost 50 per cent of the measurements. The long time constant was found to increase with bladder expansion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02447079
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 180
    Electronic Resource
    Electronic Resource
    Interfacial areas and gas hold-ups at elevated pressures in a mechanically agitated gas-liquid reactor (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 1-10 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Interfacial areas and gas hold-ups were determined at pressures of up to 1.7 MPa in a glass vessel, 88 mm in diameter and of standard geometry. Superficial gas velocities between 0.25 and 2.0 cm/s were used and the stirring speed varied between 4 and 30 rps. The interfacial areas were determined by the chemical method, using the model reaction between CO2 and aqueous diethanolamine (DEA). Hold-ups were determined by observation of differences in height. In contrast to literature indications, the gas hold-up was found to be independent of reactor pressure. This is also true for the interfacial area.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110102
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 181
    Electronic Resource
    Electronic Resource
    Effect of chlorine on the selectivity of a fischer-tropsch catalyst composed of iron/vanadium oxidesDedicated to Professor Dr. Karl Schügerl on the occasion of his sixtieth birthday (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 32-39 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Fischer-Tropsch catalysts (Fe/V oxides with ZnO and K2CO3 as promoters) were exposed to CHCl3, thereby producing surface and bulk chlorides. The effect of this exposure on activity and selectivity was studied in a continuous recycle reactor at a total pressure of 10 bar (CO/H2 in most experiments: ca 1:1) in a temperature range between 200 and 343°C. CHCl3 was introduced in amounts of up to 1 × 10-2 mol chlorine per g catalyst. The catalyst samples were characterized by internal surface area, pore-size distribution and adsorption capacities for CO, H2 and C2H4. Prior to synthesis, the catalysts were reduced by H2. Catalyst exposure to CHCl3 resulted in a decrease of activity and considerable changes in product distribution. Hydrogenation and isomerization of 1-olefins were partly suppressed; the chain length of the products was slightly increased. Deactivation of the catalysts due to chlorine addition was partly reversible during operation, while olefin formation was not significantly altered with time-on-stream. The effect of chlorine on activity and selectivity is explained by dissociation of CO as the chain initiating step and CO insertion into a carbon/metal bond as a possible chain propagation step. Since adsorption capacity for H2 decreases on the addition of chlorine, this may also contribute to lower activity and change in selectivity, compared to the unexposed catalyst.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110106
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 182
    Electronic Resource
    Electronic Resource
    A new fluid dynamic model for mixing of newtonian and power-law liquids in the transient regimeModified version of a paper presented at the “GVC Working Party on Mixing”, Trier, 4./5. May 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 162-170 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In the description of mixing processes influenced by viscosity in pseudoplastic (power-law) fluids, a definition of representative viscosity is normally used which takes into account the variable flow behaviour of the stirred material as a result of different shear stresses. In this context, the Metzner and Otto concept, which postulates that a representative shear rate is proportional to stirring speed, has become widely know, although the power calculation is inaccurate, particularly in the transient regime between the laminar and turbulent flow. A new model of fluid dynamics in the mixing vessel is presented, based on the increase of the mean flow velocity standardized with the stirrer's tip velocity in the transition regime. It provides a physical explanation for the above deviations. A suitable definition of representative viscosity substantially improves the accuracy of calculations of the stirring power in power-law fluids.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110122
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 183
    Electronic Resource
    Electronic Resource
    Influence of mechanical stress on the growth of Rhizopus nigricans in stirred bioreactorsPaper presented at the “Jahrestreffen der Verfahrensigenieure”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 178-187 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This investigation was undertaken in order to examine the factors affecting mechanical damage to micro-organisms in stirred bioreactors. Growth of the mould Rhizopus nigricans was studied in stirred bioreactors at different geometrical and operating parameters. Since experimental results cannot be described by conventional key parameters, a new concept has been suggested. It is based on the analogy to processes of mechanical disintegration. It is shown that the same key parameter, i.e. the ratio of power input to flow rate, can be used for a satisfactory correlation of experimental data on mechanical damage to micro-organisms, which is an important step in the recovery of intracellular products in biotechnology.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110124
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 184
    Electronic Resource
    Electronic Resource
    Thermal deactivation of heterogeneous catalysts. Part 2: The compensation effect and the Catalytic Paradox (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 228-236 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The interpretation of the term “compensation” obscures a logical contradiction, the catalytic paradox, which is caused by inconsistent validity ranges of the Arrhenius parameters, the pre-exponential factor and the activation energy. For this reason, a theory which contains the Arrhenius parameters cannot be established for the entire system (whole temperature range) on the basis of classical logic. Only the subsystems can be consistent and complete. One subsystem is the range of the topocatalytic concept which is relevant for thermal deactivation, thermal bistability and for all reactions with surface dependence of activity. The other is the range of the energetic concept which is preferred in fundamental research. In order to complete the subsystems, new consistent symbols are introduced. The change of particle size caused by thermal deactivation can result in four possible particle size effects, two of which have been discussed in the literature.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110130
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 185
    Electronic Resource
    Electronic Resource
    Thermal radiation of gas/solid mixturesPaper presented by Th. Elsner at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 237-243 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Thermal radiation of gas/solid mixtures in high-temperature heat exchangers is of considerable importance for the design of heat exchange surfaces. Therefore, an experimental plant was constructed to measure solid particle emissivities, since there is a lack of relevant data in the existing literature. A theoretical equation was derived to describe the solid particle emissivity as a function of layer thickness, specific solid surface area, solid loading and absorption and scatter coefficients. Measurements were carried out for fluidized bed ash and quartz sand. The emissivities of these particle fractions increase with increasing layer thickness, slid loading, specific solid surface area and temperature. The description of these data by the derived model equation is very satisfactory. No dependence on wavelength was observed. The ash components do exert some influence which, for the present, cannot be described exactly.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110131
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 186
    Electronic Resource
    Electronic Resource
    Application of modern packings in thermal separation processesPaper presented by R. Villet at ACHEMA ′85. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 213-227 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A report is presented on the performance of modern dumped and structured packings for application in the field of thermal separation processes. The evaluation of the results is based on extensive experimental investigations of rectification, absorption, and desorption systems. The following are indicated: the efficiency in terms of the number of theoretical stages per unit height or in terms of the height of transfer unit or volumetric mass transfer coefficient, the pressure drop per unit height as well as per theoretical stage or per gas phase transfer unit, and the liquid hold-up, whereby either the gas capacity factor or the liquid load was adopted as influencing parameter, and finally the maximum gas capacity factor as a function of the flow parameter. The results are presented in diagrams and tables.
    Additional Material: 25 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110129
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 187
    Electronic Resource
    Electronic Resource
    Volumetric mass transfer coefficient in stirred reactors (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 249-251 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: It is shown that the volumetric mass transfer coefficients, presented recently by Schmitz et al. [1] for viscous solutions of carboxymethyl cellulose (CMC) in aqueous sodium sulphite, are considerably underestimated as a result of unjustified neglect of the oxygen back pressure during oxygen absorption. Schmitz et. al. [1] found a decrease in the exponent n in the relationship between the oxygen mass transfer coefficient, kla, and the power dissipated per unit volume of the liquid phase, e (kla ∝ en), and ascribed it to viscosity effects. However, no such decrease is observed, provided that the actual oxygen back pressure is taken into account.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110133
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 188
    Electronic Resource
    Electronic Resource
    Mass transfer in centrifugal extractorsPaper presented by F. Otillinger at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 312-320 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This contribution presents the methods of measuring the mass transfer in centrifugal extractors and of determining it during the individual life stages of a fluid element of the dispersed liquid, i.e. drop formation, motion, coalescence and stay in the stationary layer of the dispersed phase. The experimental mass transfer coefficients of the dispersed and continuous phases are compared with well-known theoretical models developed for extraction columns in gravitational field. Due to the fast motion and coalescence of the fluid particles at high centrifugal field intensities, mass transfer in centrifugal extractors takes place during short contact times. Nevertheless, this contribution shows that mass transfer in a centrifugal field can be calculated with selected theoretical models of the gravitational field. The investigations on mass transfer are completed by a classification of the strongly deformed fluid particles in centrifugal field into regimes of circulating and oscillating drops. In addition, data on the performance of centrifugal extractors, undergoing several exchange steps, are given.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110141
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 189
    Electronic Resource
    Electronic Resource
    Effect of enzyme inhibition on the performance of packed-bed biological reactor - a theoretical study (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 50-56 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The performance characteristic of a packed bed reactor has been analyzed by considering diffusional resistance of the biofilm. Model equations were solved by the method of orthogonal collocation for various classical enzyme inhibition kinetics, including partially non-competitive, partially competitive, partially uncompetitive, partially mixed and fully mixed. For all considered modes of inhibition, an increase in the inlet substrate concentration decreases the steady state conversion in the reactor. However, an increase in the Peclet number has been found to improve the conversion. The effects of various other process variables of physical importance were also investigated parametrically.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110108
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 190
    Electronic Resource
    Electronic Resource
    Absorption of SO2 by aqueous NaOH solutions in the presence of a surfactant (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 156-162 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A report is presented on the influence of liquid flow rate, NaOH concentration, column length and presence of 5 × 10-3 wt-% of the surfactant SLS on the rate of absorption of pure SO2 by aqueous NaOH solution in a sphere-and-cylinder column. The presence of sodium lauryl sulphate (SLS) prevented axial turbulence which increased mass transfer in longer columns and was almost independent of the flow rate. The enhancement factor due to the reaction between SO2 and NaOH with respect to the process of physical absorption was analyzed for the systems with excess OH- in the outflow. The results obtained in the presence of a surfactant are satisfactorily explained by film theory with a single reaction plane model. Those obtained in the absence of surfactant are best described by a two-plane model using renewal theory.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110121
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 191
    Electronic Resource
    Electronic Resource
    Measurement of temperature fields in mixing vessels using optical topographyPaper presented by W. Ostendorf at the “Jahrsterffen der Verfahrens- Ingenieure”, Freiburg, September 30 to October 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 148-155 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Experimental investigation of stirring processes require the measurement of temperature changes and concentration profiles in all the zones of the mixing volume. The conversion of simultaneous chemical reactions during the mixing process depends on the local temperature and concentration. The time-dependent temperature and concentration fields can be recorded for the entire mixing volume with the use of optical tomography and correlated with time. This technique offers the possibility of continuous measurement of temperature and concentration changes during the mixing process throughout the measurement volume. In the described investigations, optical tomography is used to examine the transport and equalization processes during mixing in stirred vessels.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110120
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 192
    Electronic Resource
    Electronic Resource
    Effect of ethane addition on propane pyrolysis (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 243-248 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Pyrolysis of propane/argon mixture in the presence of trace quantities (0.1% and 0.9%) of ethane was investigated at reflected shock wave temperatures between 1200 and 2000K. Traces of ethane accelerated propane decomposition at high temperature. However, increase in the quantity of ethane added to propane/argon mixture did not result in the same increase of its accelerating influence. Ethylene, methane and acetylene were the main hydrocarbon reaction products, with small quantities of propylene and ethane detected only at lower temperatures. Below 1500K, addition of ethane slightly enhanced the yields of ethylene and methane at the expense of propylene and ethane respectively. The selectivity for acetylene increased with increasing temperature and with the decline of those for the other products. For none of the products, did the presence of ethane alter the relationship between product formation rates and temperature. The influence of ethane addition on propane pyrolysis at high temperatures was explained in terms of increased radical concentrations, especially hydrogen atoms and vinyl radicals, formed at high conversions. These accounted for the rapid acceleration of propane decomposition and the high yield of acetylene at high temperatures.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110132
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 193
    Electronic Resource
    Electronic Resource
    Parametric sensitivity of the ignition process to mass transfer in adiabatic tubular reactors with exothermic heterogeneous reactions (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 251-258 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The alternative effects of reaction kinetics, mass, heat and momentum transport on mass conversion by chemical reactions are examined theoretically for a reacot tube with laminar flow. The reaction enthalpy is considered. A heterogeneous reaction between several gaseous components takes place at the inner surface of this reactor tube. Strongly exothermic reactions lead to self-acceleration of the reaction, unless reaction enthalpy is removed through the tube wall. Under certain conditions, there will be a sudden change from mass transfer controlled by the reaction to that controlled by diffusion. This phenomenon is known as ignition of the reaction. The effect of ignition and its sensitivity to reaction enthalpy, thermal conductivity and diffusivity of the fluid as well as activation energy of the first order heterogeneous wall reaction are investigated by a numerical solution of the transport equations. Axial conduction of heat and mass is neglected both in the fluid and in the tube wall. Non-stoichiometric wall reactions of first order, with temperature dependent reaction rates and equilibrium constants, are considered. The results are presented in graphical form, as plots of the local mass flux at the reacting wall as functions of the dimensionless tube length.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110134
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 194
    Electronic Resource
    Electronic Resource
    Chemical engineering aspects of precipitation from solutionPaper presented by A. Mersmann at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, Spetember 30 to october 2, 1987. (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 264-276 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Precipitation is a rapid solidification. As a rule, it applies to substances which are sparingly soluble and is coupled with a chemical reaction or with a salting out process. The chemical engineer has to ensure that the product obtained has a constant and preferably coarse size distribution. This contribution compares the literature data on crystallization of soluble and sparingly soluble substances; it can be shown that, during precipitation processes, nuclei are formed, most probably by a primary mechanism. Analysis of the processes occurring during precipitation, such as chemical reaction, mixing and crystallization, leads to recommendations for the operation of precipitation processes.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110136
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 195
    Electronic Resource
    Electronic Resource
    Scale-up of mechanically agitated extraction columnsPaper presented at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, September 30 to October 2, 1987 (1988)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 11 (1988), S. 259-263 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The deterioration of mass transfer efficiency of an extraction column with increasing column diameter is the result of developing residence time distributions. These effects can be described by one-dimensional dispersion model. However, it must be verified whether the requirements for its application are fulfilled in the different types of agitated extraction columns. For the columns for which the dispersion model can be applied, a relationship will be derived between the necessary increase of column height with column diameter. This is based on the equations for calculation of the dispersion coefficient of the continuous phase. If the dispersion model cannot be applied to given a type of column, an investigation will be made on the possible modifications of operation or changes in construction, in order to permit a scale-up procedures as proposed here.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270110135
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 196
    Electronic Resource
    Electronic Resource
    Effects of β-adrenergic blockade on training-induced structural adaptations in rat left ventricle (1988)
    Springer
    European journal of applied physiology 57 (1988), S. 671-676 
    Details
    ISSN: 1439-6327
    Keywords: Rat ; Left ventricle ; Training ; Metoprolol ; Propranolol ; Capillary density ; Myocyte ; Atrophy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The study was designed to evaluate the effects of eight weeks of exercise training or training-β-adrenergic blockade combination on gross and microscopic alterations of rat cardiac muscle and microvascular bed. Rats were randomly assigned to either sedentary control (C), trained (T), metoprolol-trained (MT), or propranolol-trained (pT) groups. The training protocol involved treadmill running for 8 weeks at 0.5 m s−1, 20% grade. Earlier experiments by us showed this training protocol to be effective in producing significant changes in selected skeletal muscle enzyme activities in all trained groups. In the current study an absolute reduction in left ventricular (LV) weight was observed in the PT compared to the C group (0.91±0.02 vs. 1.04±0.04 g,P〈0.05). LV weight in the T and MT groups was no different from C so that LV to BW ratio (mg·g−1) was significantly increased (P〈0.05) due to a similar reduction in body weight (BW) in all three training groups. Morphometric analysis of LV myocardium revealed no significant differences in myocyte mean cross-sectional area (μm2) in any of the groups (289±16-C, 332±20-T, 281±44-MT, and 273±12-PT). Capillary density independently calculated by light and electron microscopy was unchanged by training or trainings-blockade combination. It was concluded that training of sufficient intensity and duration to produce skeletal muscle enzyme adaptations does not necessarily produce myocyte hypertrophy or alter LV capillarity. Additionally functioningβ-adrenergic receptors appear to play a role in both the central and peripheral adaptations to endurance exercise training.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01075987
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 197
    Electronic Resource
    Electronic Resource
    Regulation of glycogen metabolism in rat respiratory muscles during exercise (1988)
    Springer
    European journal of applied physiology 58 (1988), S. 120-124 
    Details
    ISSN: 1439-6327
    Keywords: Respiratory muscle ; Glycogen ; Exercise ; Fasting ; Nicotinic acid ; Beta-adrenergic receptors ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of prolonged exercise on the glycogen level in the respiratory muscles (diaphragm — D, external intercostal — IE and internal — II) has been studied in four groups of rats: 1-control, 2-fasted for 24 h, 3-treated with nicotinic acid and 4-treated with propranolol. There was a sharp reduction in glycogen level in each muscle after 30 min exercise in the control and fasted groups. Exercise till exhaustion further lowered the glycogen level in D in the control group and in IE and II in the fasted group. In the fasted group, the level of glycogen in each muscle, at rest, and after 30 min exercise, and in IE and II muscles after exercise till exhaustion was lower than in the control group. Nicotinic acid did not affect the glycogen level either at rest or during exercise as compared with the control group. Propranolol increased the glycogen level in the muscles at rest and during 30 min exercise. It partially prevented glycogen mobilization in D and IE and fully in II during exercise till exhaustion. In the control group, 24 and 48 h after exercise till exhaustion, the level of glycogen in each muscle exceeded the resting control value. It is concluded that exercise-induced glycogen metabolism in the respiratory muscles differs in some respects from that in the limb or heart muscles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00636614
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 198
    Electronic Resource
    Electronic Resource
    The ontogeny and phylogenetic conservation of MAP 2 forms (1988)
    Springer
    Protoplasma 145 (1988), S. 195-199 
    Details
    ISSN: 1615-6102
    Keywords: Microtubule-associated proteins ; Development ; Rat ; Quail ; Xenopus laevis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In the adult rat brain, MAP 2 is a high-molecular weight protein that is highly concentrated in dendrites. Immunoblots of homogenates of developing rat brain have indicated that a low-molecular weight form of MAP 2, MAP 2 c, is transiently expressed as the brain is undergoing morphogenesis. Using MAP 2-specific monoclonal antibodies, we have demonstrated that the compartmentalization of high-molecular weight MAP 2 and the developmental regulation of MAP 2 are conserved in mammalian, avian, and amphibian brain. We have also determined the distribution of MAP 2 c in developing neuronal tissue. MAP 2 c appears before high-molecular weight MAP 2 in developing neurons, and in contrast to the dendrite-specific high-molecular weight forms of MAP 2, MAP 2 c is present in axons and glia. We have also shown that MAP 2 c is present in the adult rat retina, where it is concentrated in regenerative photosensitive cells. The transient expression of MAP 2 c in the developing brain of three species as well as in adult photosensitive cells suggests a role for this protein in neurite growth and plasticity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01349359
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 199
    Electronic Resource
    Electronic Resource
    Immunohistochemical identification of supportive cell types in the enteric nervous system of the rat colon and rectum (1988)
    Springer
    Cell & tissue research 251 (1988), S. 523-529 
    Details
    ISSN: 1432-0878
    Keywords: Glial fibrillary acidic (GFA) protein ; S-100 protein ; Supportive cells ; Intestine ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The non-neuronal, supportive cells of the enteric nerve plexus were investigated in the colon and rectum of adult and developing rats by means of immunohistochemistry, utilizing antisera against GFA protein and S-100 protein. Immunoreactivity to GFA protein was almost exclusively found in cells associated with the myenteric plexus and a small number of cells within the submucous ganglia. On the other hand, the use of S-100 protein antiserum resulted in the visualization of all supportive elements in the enteric nervous system. However, two types of supportive cells could be tentatively differentiated in the enteric nerve plexus during the second week of postnatal development, using GFA protein and S-100 protein antisera; GFA protein-positive cells were clearly discernible from S-100 protein-positive cells in terms of both the morphological profiles and immunohistochemical properties. It was assumed that at least two different types of supportive cells are contained in the enteric nerve plexus. We suggest that in the enteric nervous system the terms “glial cells” and “Schwann cells” should be employed to designate the supportive cells containing GFA and S-100 proteins, and cells containing S-100 protein, respectively. We discuss the possibility that glial cells are associated with the parasympathetic preganglionic fibres directly derived from the central nervous system, while Schwann cells originate from the neural crest.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213999
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 200
    Electronic Resource
    Electronic Resource
    Ultrastructure of the meninges at the site of penetration of veins through the dura mater, with particular reference to Pacchionian granulations (1988)
    Springer
    Cell & tissue research 251 (1988), S. 621-631 
    Details
    ISSN: 1432-0878
    Keywords: Perivascular space ; Cerebrospinal fluid compartments ; Dura mater ; Pacchionian granulations ; Rat ; Cebus apella, Callitrix jacchus (Primates)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary At the sites where a vein penetrates through the dura mater, two aspects deserve particular attention: (i) The delineation of the perivascular cleft, a space belonging to the interstitial cerebrospinal fluid (CSF) compartment, toward the interior hemal milieu of the dura mater. (ii) The relationship between the perivascular arachnoid layer and the subdural neurothelium at the point of vascular penetration. These problems were investigated in the rat and in two species of New-World monkeys (Cebus apella, Callitrix jacchus). Concerning the first aspect, tight appositions of meningeal cells to the vessel wall, the basal lamina of which is widened and enriched with microfibrils, prevent communication between the interstitial CSF in the perivascular cleft and the hemal milieu in the dura mater. With reference to the second aspect, the perivascular arachnoid cells are transformed into neurothelial cells at the point where they become exposed to the hemal milieu of the dura mater and subsequently continuous with the subdural neurothelium. Leptomeningeal protrusions encompassing outer CSF space can penetrate into the dura mater. These protrusions may expand and branch repeatedly, forming along the wall of the durai sinus Pacchionian granulations. At these sites, however, the structural integrity of the sinus wall and the Pacchionian granulation is not lost. Numerous vesiculations not only in the sinus and vascular walls, but also in the cellular arrays of the Pacchionian granulations or paravascular leptomeningeal protrusions indicate mechanisms of transcellular fluid transport. Moreover, the texture of the leptomeningeal protrusions favors an additional function of these structures as a “volume” buffer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00214011
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...