Hydrostatic pressures and movements of the lamprey, Petromyzon, during suction, olfaction, and gill ventilation

1972 ◽  
Vol 50 (9) ◽  
pp. 1215-1223 ◽  
Author(s):  
Norman Gradwell
Keyword(s):  
Ambient Pressure ◽  
Pressure Waveform ◽  
Quiet Breathing ◽  
Water Tube ◽  
Gill Ventilation ◽  
Tongue Movements

Sucker pressures are negative relative to ambient pressure, except for the sucker's anterior periphery, where positive pressures prevail. Pressures associated with small rhythmic as well as large sporadic branchial movements are transmitted to the sucker and naris. However, sucker pressures (as great as −90 to 110 cm H2O) associated with tongue movements are not transmitted to the naris or gill pouches. Manual abduction of the sucker caused suction to exceed −120 cm H2O before disengagement. The complex sucker pressure waveform suggests that it is generated by branchial movements combined with some other factors, as yet unknown. During quiet breathing there is no apparent intermixing of water between different gill pouches via their internal confluence with the water tube.

A noninvasive intraoral electromyographic electrode for genioglossus muscle

1985 ◽  
Vol 58 (4) ◽  
pp. 1378-1382 ◽  
Author(s):  
E. A. Doble ◽  
J. C. Leiter ◽  
S. L. Knuth ◽  
J. A. Daubenspeck ◽  
D. Bartlett
Keyword(s):  
Bioelectrical Activity ◽  
Electromyographic Activity ◽  
Surface Electrode ◽  
Quiet Breathing ◽  
Frequency Spectra ◽  
Genioglossus Muscle ◽  
Intramuscular Electrodes ◽  
Superior Surface ◽  
Tongue Movements ◽  
Relationship Of

We have developed an intraoral bipolar surface electrode for the genioglossus muscle. The electrode, made from an athletic mouthguard and dental impression material, was fitted to the lower teeth. Electrode wires, bared at the tip, were positioned on the bottom of the mouthpiece to lie in contact with the superior surface of the genioglossus just behind the teeth. The electromyographic activity of the genioglossus, simultaneously obtained from the surface electrode and conventional intramuscular electrodes, was compared during quiet breathing, CO2 rebreathing, and a variety of tongue movements. The two types of electrodes recorded similar patterns of muscle activity, and spectral analyses of the signals revealed similar and highly coherent frequency spectra. We conclude that the surface electrode satisfactorily reflects the bioelectrical activity of the genioglossus. The mouthpiece electrode has the further advantage that quantitative comparisons can be made among recordings made in different experimental sessions, since the fit of the mouthpiece to the teeth assures a constant relationship of the electrode to the genioglossus muscle.

The neurophysiology of respiration in decapod crustacea. I. The motor system

1968 ◽  
Vol 46 (3) ◽  
pp. 585-596 ◽  
Author(s):  
Valerie M. Pasztor
Keyword(s):  
Action Potentials ◽  
Motor Command ◽  
Blue Staining ◽  
Fiber Types ◽  
Quiet Breathing ◽  
Inhibitory System ◽  
Decapod Crustacea ◽  
Phasic Type ◽  
Gill Ventilation ◽  
Frequency Burst

The pump responsible for gill ventilation in the crayfish is operated by 11 muscles of the second maxillae. These muscles arc described and named and their action analyzed by the recording of nerve and muscle potentials. During quiet breathing, the normal motor command to each muscle is a short, high-frequency burst of evenly spaced action potentials (7–25 spikes at average frequencies of 60–140/sec). Histological and physiological evidence shows that the muscles represent mixed populations of fiber types. Most fibers are of the "gradedly responding" phasic type. Although methylene blue staining reveals two axons to each muscle, the normal motor command arrives via one axon only. The second may be a "fast" axon operating only in exceptional circumstances. No evidence has been found of a peripheral inhibitory system.

Environmental microscopy of capillary stress-induced strain behavior in ambient-pressure aerogels

1996 ◽  
Vol 54 ◽  
pp. 850-851
Author(s):  
Sudeep M. Rao ◽  
Joshua Samuel ◽  
Sai S. Prakash ◽  
C. Jeffrey Brinker
Keyword(s):  
Silica Aerogel ◽  
Ambient Pressure ◽  
Drying Shrinkage ◽  
Pore Filling ◽  
Silica Network ◽  
Strain Behavior ◽  
Partially Saturated ◽  
Capillary Stress ◽  
Wetting Liquid ◽  
Aerogel Films

Ambient pressure silica aerogel thin films have recently been prepared by exploiting reversible drying shrinkage caused by derivatization of the internal gel surface. Aerogels have porosities of upto 99.9% and due to the small size of the pores (few nanometers), large capillary stresses are produced in gels that are partially saturated with a wetting liquid. As a result of these capillary stresses, the flexible silica network undergoes strain which has been observed using environmental microscopy. This technique allows variation of the equilibrium vapor pressure and temperature, and a simultaneous monitoring of the deformation of the unconstrained film thickness. We have observed >600% deformation during the pore-filling and pore-emptying cycles. In this presentation, we discuss the unique stress-strain behavior of these films.Ref.: Sai S. Prakash, C. Jeffrey Brinker, Alan J. Hurd & Sudeep M. Rao, "Silica aerogel films prepared at ambient pressure by using surface derivatization to induce reversible drying shrinkage", Nature. Vol. 374, 30 March, 1995, 439-443.

Signal Interpretation Considerations When Estimating Subglottal Pressure From Oral Air Pressure

2019 ◽  
Vol 62 (5) ◽  
pp. 1326-1337 ◽  
Author(s):  
Brittany L. Perrine ◽  
Ronald C. Scherer ◽  
Jason A. Whitfield
Keyword(s):  
Standard Condition ◽  
Word Production ◽  
Air Pressure ◽  
Pressure Waveform ◽  
Pressure Measurements ◽  
Air Leak ◽  
Pressure Signal ◽  
Adult Participants ◽  
Syllable Repetition ◽  
Subglottal Pressure

Purpose Oral air pressure measurements during lip occlusion for /pVpV/ syllable strings are used to estimate subglottal pressure during the vowel. Accuracy of this method relies on smoothly produced syllable repetitions. The purpose of this study was to investigate the oral air pressure waveform during the /p/ lip occlusions and propose physiological explanations for nonflat shapes. Method Ten adult participants were trained to produce the “standard condition” and were instructed to produce nonstandard tasks. Results from 8 participants are included. The standard condition required participants to produce /pːiːpːiː.../ syllables smoothly at approximately 1.5 syllables/s. The nonstandard tasks included an air leak between the lips, faster syllable repetition rates, an initial voiced consonant, and 2-syllable word productions. Results Eleven oral air pressure waveform shapes were identified during the lip occlusions, and plausible physiological explanations for each shape are provided based on the tasks in which they occurred. Training the use of the standard condition, the initial voice consonant condition, and the 2-syllable word production increased the likelihood of rectangular oral air pressure waveform shapes. Increasing the rate beyond 1.5 syllables/s improved the probability of producing rectangular oral air pressure signal shapes in some participants. Conclusions Visual and verbal feedback improved the likelihood of producing rectangular oral air pressure signal shapes. The physiological explanations of variations in the oral air pressure waveform shape may provide direction to the clinician or researcher when providing feedback to increase the accuracy of estimating subglottal pressure from oral air pressure.

ON MAGNETIC PROPERTIES 0F (TMTSF)2PF6AT AMBIENT PRESSURE

1983 ◽  
Vol 44 (C3) ◽  
pp. C3-1001-C3-1005
Author(s):  
S. Iwabuchi ◽  
H. Fukuyama
Keyword(s):  
Magnetic Properties ◽  
Ambient Pressure

NEAR-WALL CHARACTERISTICS OF AN IMPINGING GASOLINE SPRAY AT INCREASED AMBIENT PRESSURE AND WALL TEMPERATURE

2009 ◽  
Vol 19 (11) ◽  
pp. 997-1012 ◽  
Author(s):  
Jochen Stratmann ◽  
D. Martin ◽  
P. Unterlechner ◽  
R. Kneer
Keyword(s):  
Wall Temperature ◽  
Ambient Pressure ◽  
Near Wall

Effect of ambient pressure on low-density nozzle plumes

1995 ◽  
Author(s):  
Chan-Hong Chung ◽  
Kenneth D ◽  
Robert Stubbs
Keyword(s):  
Ambient Pressure ◽  
Low Density

Influence of intramolecular interactions on carbon dioxide gas adsorption capacity in Mesoporous Imine polymers

2018 ◽  
Author(s):  
Jaya Prakash Madda ◽  
Pilli Govindaiah ◽  
Sushant Kumar Jena ◽  
Sabbhavat Krishna ◽  
Rupak Kishor
Keyword(s):  
Carbon Dioxide ◽  
Adsorption Capacity ◽  
Density Functional ◽  
Gas Adsorption ◽  
Ambient Pressure ◽  
Condensation Reaction ◽  
Intramolecular Interactions ◽  
Carbon Dioxide Adsorption ◽  
Nitrogen Gas ◽  
Adsorption Characteristic

<p>Covalent organic Imine polymers with intrinsic meso-porosity were synthesized by condensation reaction between 4,4-diamino diphenyl methane and (para/meta/ortho)-phthaladehyde. Even though these polymers were synthesized from precursors of bis-bis covalent link mode, the bulk materials were micrometer size particles with intrinsic mesoporous enables nitrogen as well as carbon dioxide adsorption in the void spaces. These polymers were showed stability up to 260<sup>o</sup> centigrade. Nitrogen gas adsorption capacity up to 250 cc/g in the ambient pressure was observed with type III adsorption characteristic nature. Carbon dioxide adsorption experiments reveal the possible terminal amine functional group to carbamate with CO<sub>2</sub> gas molecule to the polymers. One of the imine polymers, COP-3 showed more carbon dioxide sorption capacity and isosteric heat of adsorption (Q<sub>st</sub>) than COP-1 and COP-2 at 273 K even though COP-3 had lower porosity for nitrogen gas than COP-1 and COP-2. We explained the trends in gas adsorption capacities and Qst values as a consequence of the intra molecular interactions confirmed by Density Functional Theory computational experiments on small molecular fragments.</p>

Sign in / Sign up

Export Citation Format

Share Document