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  • Digitale Medien  (11)
  • Tolerance  (5)
  • Allelopathy  (3)
  • Industrial Chemistry  (3)
  • 1
    Digitale Medien
    Digitale Medien
    Development and loss of tolerance to the effects of ethanol on DRL performance of rats (1989)
    Springer
    Psychopharmacology 97 (1989), S. 45-50 
    Details
    ISSN: 1432-2072
    Schlagwort(e): DRL ; Ethanol ; Operant behavior ; Rats ; Residual tolerance ; Tolerance ; Rate increases and decreases
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Six male Sprague-Dawley rats were trained on a DRL-20 operant schedule for food presentation. When stable performance was established, they were exposed to an escalating regimen of daily ethanol administration (1.125–3.75 g/kg. IP). This dosing regimen continued until the maximally tolerable dose for each subject was reached. Tolerance loss then was monitored for approximately 6 months by periodic ethanol challenge doses (1.5 g/kg). Dose-effect curves (DECs) were obtained prior to (DEC-1), immediately after (DEC-2), and 6 months following termination of (DEC-3) the ethanol exposure. Rate-increasing effects (DEC-1) were noted at low doses (0.75 and 1.125 g/kg), with a higher dose (2.25 g/kg) resulting in a decreased rate of responding. Tolerance, following chronic ethanol exposure, developed to both the rate-increasing and ratedecreasing effects of ethanol (DEC-2). While some tolerance was lost within the 6 months following the daily ethanol exposure (DEC-3), a significant degree of tolerance was still indicated by most of the response measures. This duration of tolerance was considerably longer than that generally reported, and is probably attributable to persistent learned compensatory behavior and/or intermittent ethanol challenge tests.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00443411
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  • 2
    Digitale Medien
    Digitale Medien
    Schedule-controlled behavior as an index of the development and loss of ethanol tolerance in the rat (1985)
    Springer
    Psychopharmacology 87 (1985), S. 414-420 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Behavioral tolerance ; Ethanol ; Operant behavior ; Rats ; Residual tolerance ; Tolerance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Twelve male Sprague-Dawley rats, following training on one of two food-motivated operant schedules (Fixed-Ratio 30 or Variable Interval 30 s), were exposed to an escalating regimen of daily ethanol (1.125–3.0 g/kg, IP) administration. This increasing dose regimen continued until the maximally tolerable dose for each subject was reached. Tolerance was then monitored for approximately 6 months by periodic ethanol challenge doses (1.5 g/kg). Dose-effect curves (DECs) were obtained prior to chronic ethanol (DEC1), immediately after ethanol tolerance development (DEC2), and 6 months (DEC3) following termination of ethanol exposure. At DEC1, ethanol produced dose-dependent decreases in rate on both schedules with no significant schedule differences in ED50 (the dose effective at reducing the maximal response rate by one-half) values. Maximal tolerance was achieved in means of 46 and 55 days on the VI and FR schedules, respectively. Differences in rate of tolerance acquisition on the initial dose of the chronic regimen (1.125 g/kg) account for most of the difference in the overall rate of acquisition. Comparison of the ED50 data from DECs 1 and 2 indicated that daily ethanol exposure resulted in a 2-fold decrease in ethanol sensitivity (i.e., tolerance) on both operant schedules. The ED50 data from DECs 1 and 3 demonstrated a 1.7-fold decrease in ethanol potency on DEC3. This duration of tolerance was considerably longer than that generally reported, and possibly related to the extended ethanol exposure and the sensitivity of operant schedules to drug effects.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00432505
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  • 3
    Digitale Medien
    Digitale Medien
    Tolerance to ethanol's effects on operant performance in rats: role of number and pattern of intoxicated practice opportunities (1992)
    Springer
    Psychopharmacology 109 (1992), S. 112-120 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Ethanol ; Operant performance ; Tolerance ; Intoxicated practice ; Compensatory behaviors ; Acute ethanol withdrawal
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Acquisition and retention of tolerance to ethanol's rate-decreasing effects on operant performance were examined in rats which received a 52-day regimen of ethanol or saline injections prior to and/or after each daily session. Eight groups of rats differed on: (a) number of days with intoxicated practice (pre-session ethanol); (b) intermittent (spaced) or daily (massed) intoxicated practice; and (c) post-session ethanol or saline on nonintoxicated practice days. Massed practice groups were given their presession saline days prior to their pre-session ethanol days. Ethanol dose-effect tests were given prior to, during, and after the chronic injection regimen. Under both spaced and massed practice conditions, the magnitude of tolerance developed increased directly with the number of pre-session ethanol days, even when absolute ethanol exposure was constant. No group showed complete tolerance loss. The post-session ethanol supplements (a) facilitated tolerance development in spaced practice groups and tolerance loss in massed practice groups, (b) blocked ethanol's low dose rate-increasing effects, and (c) produced an acute withdrawal-like performance disruption the next day. The results suggest that both intoxicated practice and practice during acute ethanol withdrawal influence the acquisition and retention of compensatory behaviors during ethanol tolerance development.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02245488
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  • 4
    Digitale Medien
    Digitale Medien
    Urinary cyclic AMP excretion by methadone subjects during gradual and acute withdrawal (1977)
    Springer
    Psychopharmacology 54 (1977), S. 17-20 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Methadone ; Cyclic AMP ; Tolerance ; Physical dependence ; Withdrawal
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Laboratory and animal investigations have supported the hypothesis that levels of cyclic AMP are stable during tolerance to narcotic drugs and increased during withdrawal. In order to test this hypothesis, serial 24-h urinary excretion of cyclic AMP by long-term methadone addicts was determined during a period of stable methadone intake, a period of gradual withdrawal, and a period of acute withdrawal. Cyclic AMP excretion during stable methadone intake is identical to that of normal control subjects. Neither gradual nor acute withdrawal appears to affect the urinary excretion of cyclic AMP. These data agree with previous reports in the literature which suggest that cyclic AMP levels are not altered during tolerance to narcotics, but do not support the hypothesis that levels of the nucleotide might be increased during withdrawal.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00426534
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  • 5
    Digitale Medien
    Digitale Medien
    Tolerance to ethanol's disruptive effects on operant behavior in rats (1989)
    Springer
    Psychopharmacology 99 (1989), S. 479-485 
    Details
    ISSN: 1432-2072
    Schlagwort(e): Ethanol ; Tolerance ; Operant performance ; Delayed ethanol effect ; Drug-induced compensatory learning
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The effects of pre-session and post-session daily ethanol injections on the development and loss of tolerance to ethanol's effects on fixed ratio operant performance in rats was assessed using a cumulative dosing procedure. Daily pre-session ethanol administration produced a greater decrease in ethanol sensitivity than did daily post-session ethanol. Both tolerance effects persisted for at least 1 month after the chronic injection phase. No changes in ethanol sensitivity were apparent in the saline control group and no changes in estimated blood ethanol levels were found after the chronic treatments. The post-session ethanol groups displayed a performance decrement during the initial segment of the chronic injection period, but improved significantly across the chronic phase. These data suggest that some delayed effect of ethanol initially impaired performance but that tolerance to this ethanol effect also occurred and probably contributed to the decline in ethanol sensitivity seen in these groups. Compensatory learning as the mechanism for tolerance development in the pre-session and post-session ethanol groups was supported by the finding of no change in ethanol sensitivity in rats exposed to comparable daily ethanol without any concurrent operant task on which the direct, immediate, or indirect, delayed ethanol effects could operate.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00589895
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  • 6
    Digitale Medien
    Digitale Medien
    Bioassay of naturally occurring allelochemicals for phytotoxicity (1988)
    Springer
    Journal of chemical ecology 14 (1988), S. 1821-1828 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Allelopathy ; bioassay ; mechanism of action ; seed germination ; radicle growth ; seedling growth ; Lemna bioassay
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The bioassay has been one of the most widely used tests to demonstrate allelopathic activity. Often, claims that a particular plant species inhibits the growth of another are based entirely on the seed germination response to solvent extracts of the suspected allelopathic plant; few of these tests are of value in demonstrating allelopathy under natural conditions. The veracity of the bioassay for evaluating naturally occurring compounds for phytotoxicity depends upon the physiological and biochemical response capacity of the bioassay organism and the mechanism(s) of action of the allelochemicals. The possibility that more than one allelochemical, acting in concert at very low concentrations, may be responsible for an observed allelopathic effect makes it imperative that bioassays be extremely sensitive to chemical growth perturbation agents. Among the many measures of phytotoxicity of allelochemicals, the inhibition (or stimulation) of seed germination, radicle elongation, and/or seedling growth have been the parameters of choice for most investigations. Few of these assays have been selected with the view towards the possible mechanism of the allelopathic effect.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01013479
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  • 7
    Digitale Medien
    Digitale Medien
    Prior cropping with grain sorghum inhibits weeds (1989)
    Springer
    Journal of chemical ecology 15 (1989), S. 951-960 
    Details
    ISSN: 1573-1561
    Schlagwort(e): Allelopathy ; grain sorghum ; Sorghum bicolor ; weed inhibition ; weed management
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Three years of field data in northeastern Nebraska demonstrate that a grain sorghum crop reduces weediness in the following crop year. Weed growth was consistently lower in sorghum areas the year after strip-cropping fields with sequences of four-row bands of grain sorghum, soybeans, and corn. Percentage weed cover was significantly lower early in the year, and midsummer weed biomass was well below that found after corn and soybeans. Weed biomass in June and July following corn was two to four times that of grain sorghum strips. Inhibitory effects of grain sorghum were primarily on broadleaf weeds, often showing no action on grass weeds. No obvious differences were noted in the weed species present after the three crops. Allelopathy provides a logical explanation for the sorghum-mediated weed inhibition found in this study. The data have implications for weed management strategies in agriculture.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01015190
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  • 8
    Digitale Medien
    Digitale Medien
    The effects of ferulic acid on the mineral nutrition of grain sorghum (1987)
    Springer
    Plant and soil 98 (1987), S. 99-109 
    Details
    ISSN: 1573-5036
    Schlagwort(e): Allelopathy ; Ferulic acid ; Magnesium ; Mineral content ; Phosphorus ; PotassiumSorghum bicolor
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Two week old sorghum seedlings (Sorghum bicolor L. Moench) were treated with ferulic acid added to the nutrient solution. Effects on tissue concentration of P, K, Mg, Ca, Fe, and Zn were evaluated after 3 and 6 days. Treatemnts of 0.25 mM ferulic acid approximated the growth inhibition threshold, and after 6 days 0.5 mM treated plants weighed less than controls. Both treatments reduced the P content of the roots and shoots at the 3- and 6-day harvests in three replicate experiments. Roots of treated plants at both harvests had a lower concentration of K and Mg. These reductions in P, K, and Mg were most extensive from the 0.5 mM ferulic acid regime. In some cases at both harvests, shoot K was lower and Mg was higher than control tissue. Ferulic acid effects at the 3-day harvest included an elevation of Ca and depression of Fe in shoots. Changes in nutrient content preceded measurable differences in plant weight. These data indicate that one mechanism of growth inhibition by this allelochemical may be an alteration of nutrient balance.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02381731
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  • 9
    Digitale Medien
    Digitale Medien
    Wärme- und Stoffaustausch zwischen Dampfblase und Flüssigkeit bei Stickstoff/Sauerstoff-GemischenAuszug aus der Dissertation, Eidg. Technische Hochschule Zürich, 1958, Prom.-Nr. 2827, Referent: Prof. Dr. P. Grassmann. (1960)
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 32 (1960), S. 330-335 
    Details
    ISSN: 0009-286X
    Schlagwort(e): Chemistry ; Industrial Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Beim System Stickstoff/Sauerstoff wurden bei Atmosphärendruck Wärme- und Stoffaustausch zwischen Dampf und Flüssigkeit verfolgt. Das Gas strömte dabei in Blasen, die an einer einzelnen Öffnung mit Kreisquerschnitt gebildet wurden, durch eine ruhende Flüssigkeit. Gaszusammensetzung, Flüssigkeits-zusammensetzung und Flüssigkeitsstand über der Düse konnten dabei beliebig, die Temperatur der Flüssigkeit, die Eintrittstemperatur des Gases, Düsendurchmesser und eingeblasener Gasstrom beschränkt variiert werden. Entstehung und Aufstieg der Blasen in der Flüssigkeit wurden in Zeitdehner-filmen festgehalten. Dabei wurde festgestellt, daß das Verstärkungsverhältnis in den untersuchten Intervallen der Variablen von folgenden Größen abhängt: Flüssigkeitszusammensetzung, Durchsatz durch die Düse, Austauschstrecke des Dampfes durch die Flüssigkeit und Richtungssinn des Stoffaustausches.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cite.330320503
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  • 10
    Digitale Medien
    Digitale Medien
    Steuerungen und Regelungen von Betriebsanlagen der pharmazeutischen Chemie (1965)
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 37 (1965), S. 232-234 
    Details
    ISSN: 0009-286X
    Schlagwort(e): Chemistry ; Industrial Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Die Synthesen der pharmazeutischen Produkte umfassen meist zahlreiche Stufen, wobei Chargenprozesse mit kontinuierlichen Prozessen abwechseln. Daher müssen auch die kontinuierlich arbeitenden Apparaturen oft angehalten werden. Diese Besonderheit muß bei der Auswahl der Schaltelemente berücksichtigt werden.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cite.330370310
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