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  • 1
    Electronic Resource
    Electronic Resource
    Sensation and control of breathing: A dynamic model (1991)
    Springer
    Annals of biomedical engineering 19 (1991), S. 251-272 
    Details
    ISSN: 1573-9686
    Keywords: Sensation ; CO2 rebreathing ; Exercise ; Dynamic controller ; Optimal control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract A dynamic model of the CO2 respiratory control system is proposed, which can provide a qualitative basis for predicting breathing sensations. The discomfort index, which represents breathing sensations, is assumed to be composed of two sources: the arterial CO2 level and the respiratory motor command. The respiratory controller receives inhibitory neuromechanical and excitatory CO2 signals from the plant. The CO2 signal is enhanced by exercise stimuli. This dynamic multiplicative-type controller is used in simulations of key experiments: exercise and CO2 rebreathing with and without resistive loading. The dynamics of the discomfor index, the respiratory motor command, ventilation, and arterial CO2 concentration conform to the experimental data. The perceptual sensitivity to CO2 relative to respiratory effort is significantly correlated with the slope of hypercapnic ventilatory response. This result shows a clear linkage between ventilatory response and breathing sensations. Although it is shown that the automatic controller effectively minimizes the discomfort index for perturbations about an operating point under certain conditions, the discomfort index itself does not seem to be an underlying control principle of the proposed automatic controller model. Rather, breathing sensations may influence ventilatory responses by modifying the output of the automatic controller.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00000002
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  • 2
    Electronic Resource
    Electronic Resource
    Sex pheromone of cranberry fruitworm,Acrobasis vaccinii riley (Lepidoptera: Pyralidae) (1994)
    Springer
    Journal of chemical ecology 20 (1994), S. 3269-3279 
    Details
    ISSN: 1573-1561
    Keywords: Cranberry fruitworm ; Lepidoptera ; Pyralidae ; Acrobasis vaccinii ; sex pheromone ; (E,Z)-8,10-pentadecadien-l-ol acetate ; (E)-9-pentadecen-l-ol acetate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The following compounds and (approximate ratios) were identified in sex pheromone gland extracts of femaleAcrobasis vaccinii Riley by comparison of gas chromatography-mass spectrometric traces with those of synthetic standards: (E,Z)-, (Z,E)-, (Z,Z), and (E,E)-8, 10-pentadecadien-l-ol acetates (100:1:2:12), a dodecen-l-ol acetate (8), (Z)-8-, (Z)-9-, and (E)-9-pentadecen-l-ol acetates (3:23:4), two heptadecen-l-ol acetates (4:4), tetradecyl, pentadecyl, hexadecyl, and heptadecyl acetates (3:15:10:8), dodecan-l-ol (6), tetradecan-l-ol (5), and hexadecan-l-ol (23). The amount of (E,Z)-8, 10-pentadecadien-l-ol acetate (E8,Z10–15:Ac) in the extract was about 0.5 ng/female. Electroantennographic analysis of gas chromatographic fractions of female sex pheromone gland extract showed that the fraction containingE8,Z10–15:Ac elicited the greatest response. Alone,E8,Z10–15:Ac failed to elicit upwind flight of males in flight-tunnel tests, and traps baited with it did not catch males in field experiments. WhenE8,Z10–15:Ac was combined with (E)-9-pentadecen-l-ol acetate (100:4), male upwind flight response in flight-tunnel tests was equivalent to those obtained with extract of female sex pheromone glands (synthetic, 62%; natural, 51%), but the percent of males flying upwind that contacted the source was lower (synthetic, 47%; natural, 88%). The lower percent of source contact elicited by the synthetic pheromone could be a result of the difference in isomer ratios of 8,10–15:Ac in the natural and synthetic pheromone or could indicate that the synthetic pheromone is incomplete. Traps baited with the 100:4 combination caught large numbers of males in field experiments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02033725
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  • 3
    Electronic Resource
    Electronic Resource
    Perceptual contributions to optimization of breathing (1993)
    Springer
    Annals of biomedical engineering 21 (1993), S. 509-515 
    Details
    ISSN: 1573-9686
    Keywords: Ventilatory control ; Dyspnea ; Optimal control ; Reflex control ; Automatic control ; Behavioral control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract Besides regulating the energetic cost of breathing, optimization of breathing may involve the alleviation of an uncomfortable breathing sensation. In this article, we consider perceptual contributions to the optimization of breathing. Just as the cost function proposed by Poon depends on ventilation and arterial $$P_{CO_2 }$$ so does the sense of dyspnea. Consequently, we examined the relationship between breathing discomfort and Poon's cost function. Based on our model and psychophysical studies, it appears that braathing discomfort, which can integrate chemical and mechanical inputs to the respiratory controller, may not operate simply as an estimate of a cost function. We explain how our reflex control model can dynamically minimize a cost function such as Poon's. Also, we consider the influence of willful adjustments of ventilation on breathing discomfort. From this we infer that ventilatory optimization may emerge from automatic reflexes and behavioral responses that involve excitatory chemical and inhibitory neuromechanical feedbacks.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00000006
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