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  • 1
    ISSN: 1432-2072
    Keywords: Latent inhibition ; Dopamine ; Ondansetron ; 5HT3 antagonists ; Amphetamine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Latent inhibition (LI) is a behavioural phenomenon whereby preexposure to a stimulus without reinforcement interferes with the formation of subsequent associations to that stimulus. Using preexposure to a tone stimulus which subsequently serves as a conditioned stimulus for suppression of licking, we have confirmed that LI is disrupted by a low dose of amphetamine. Haloperidol was able to prevent this effect of amphetamine. Ondansetron, a selective and potent 5HT3 receptor antagonist, was also shown to be effective at blocking the amphetamine-induced disruption of LI at a dose of 0.01 mg/kg, but not at 0.1 mg/kg. In addition, it was demonstrated that ondansetron could enhance LI; using only ten preexposures, no LI was obtained in the saline group, but was apparent in animals given ondansetron, an effect which has been previously shown with haloperidol. Haloperidol, at the higher dose used, reduced suppression of licking, however, ondansetron at the effective dose had no such effect. It is concluded that ondansetron is able to attenuate increases in dopamine activity, produced pharmacologically with amphetamine without affecting baseline dopamine activity. The implications of these findings for a possible antipsychotic action of ondansetron are discussed.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-2072
    Keywords: Nicotine ; Latent inhibition ; Dopamine ; N. accumbens ; Haloperidol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Latent inhibition (LI) is a cognitive process whereby repeated exposure of a stimulus without consequence impedes the formation of subsequent associations with that stimulus. A number of studies in the rat have reported that LI is impaired by moderate systemic doses of amphetamine, an effect believed to be mediated via dopamine (DA) release in the nucleus accumbens. We and others have reported that nicotine has a selective effect in releasing DA in the accumbens rather than the caudate nucleus. We have therefore examined the ability of nicotine to disrupt LI, using a conditioned emotional response paradigm. Pre-exposure of a tone stimulus impaired subsequent conditioning between that stimulus and mild footshock, as indexed by suppression of licking by the tone subsequently presented alone. This LI effect was prevented, by an effect confined to the pre-exposed group, by doses of 0.4 or 0.6 mg/kg nicotine SC, which are accumbens selective, given before pre-exposure and before conditioning. The effect of nicotine in disrupting LI was prevented by prior administration of haloperidol at a dose (0.5 mg/kg) reported to reverse the disruptive effect of amphetamine on LI. Although the amphetamine effect requires two administrations, the effect of two administrations of nicotine was reproduced by a single dose of nicotine given before conditioning, but not by a single dose before pre-exposure. The results are discussed in relation to studies in human control and schizophrenic subjects, which suggest that increased DA activity in humans is also associated with impaired LI. The results indicate that nicotine does indeed increase functional DA activity in the rat accumbens; the consequent disruption of LI critically depends upon an action at the time of conditioning, and is independent of processes which occur during pre-exposure. In more general terms, this indicates the potential of drug experiments to complement behavioural studies on the mechanism of latent inhibition.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 38 (1992), S. 1593-1608 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A huge amount of data is collected by computer monitoring systems in the chemical process industry. Such tools as principal component analysis and partial least squares have been shown to be very effective in compressing this large volume of noisy correlated data into a subspace of much lower dimension than the original data set. Because most of what is eliminated is the collinearity of the original variables and the noise, the bulk of the information contained in the original data set is retained. The resulting low dimensional representation of the data set has been shown to be of great utility for process analysis and monitoring, as well as in selecting variables for control. These types of models can also be used directly in control system design. One way of approaching this is to use the loading matrices as compensators on the plant. Some advantages of using this approach as part of the overall control system design include automatic decoupling and efficient loop pairing, as well as natural handling of nonsquare systems and poorly conditioned systems.
    Additional Material: 20 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Brookfield, Conn. : Wiley-Blackwell
    Journal of Vinyl and Additive Technology 12 (1990), S. 136-141 
    ISSN: 0193-7197
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: During the past decade, advances in both hardware and software have made NMR spectroscopy an enormously powerful analytical technique. In this paper, the author presents examples of the use of NMR in support of vinyl stabilizer research; he also covers representative practical applications of proton, carbon, phosphorus, and tin NMR.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
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