Respiratory transfer impedances with pressure input at the mouth and chest

1986 ◽  
Vol 61 (1) ◽  
pp. 81-86 ◽  
Author(s):  
R. Peslin ◽  
C. Gallina ◽  
C. Duvivier
Keyword(s):  
Chest Wall ◽  
Network Model ◽  
Airway Resistance ◽  
Normal Subjects ◽  
Respiratory Resistance ◽  
Pressure Flow ◽  
Transfer Impedance ◽  
Tissue Compliance ◽  
Practical Conclusion ◽  
The Relationship

Two methods of measuring respiratory transfer impedance (Ztr) were compared in 14 normal subjects, from 4 to 30 Hz, 1) studying the relationship between transrespiratory pressure (Prs) and flow at the chest when varying pressure at the mouth (Ztrm) and 2) studying the relationship between Prs and flow at the mouth when varying pressure around the chest wall (Ztrw). The similarity of the two relationships was expected on the basis of a T-network model. Almost identical phase responses were obtained from the two methods. Pressure-flow ratios were slightly larger for Ztrw than for Ztrm, but differences did not exceed 2% on average in 11 of 14 subjects. When the data were analyzed with the six-coefficient model proposed by DuBois et al. (J. Appl. Physiol. 8: 587–594, 1956), similar values were found for tissue compliance and tissue inertance but slightly different values for gaseous inertance in the airways (1.97 +/- 0.35 X 10(-2) cmH2O X l-1 X s2 for Ztrw vs. 1.73 +/- 0.26 for Ztrm; P less than 0.01). Similar results were also found for total respiratory resistance but with a slightly larger contribution of airway resistance for Ztrw (64 +/- 14 vs. 57 +/- 10%; P less than 0.05). As a practical conclusion it is recommended to measure Ztrw, which is technically much easier.

Frequency response of the chest: modeling and parameter estimation

1975 ◽  
Vol 39 (4) ◽  
pp. 523-534 ◽  
Author(s):  
R. Peslin ◽  
J. Papon ◽  
C. Duviver ◽  
J. Richalet
Keyword(s):  
Frequency Response ◽  
Gas Flow ◽  
Airway Resistance ◽  
Mechanistic Model ◽  
Normal Subjects ◽  
Order Equation ◽  
Mean Values ◽  
Tissue Compliance ◽  
Linear Differential ◽  
Gas Compressibility

The frequency response of the respiratory system was studied in the range from 3 to 70 Hz in 15 normal subjects by applying sinusoidal pressure variations around the chest and measuring gas flow at the mouth. The observed input-output relationships were systematically compared to those predicted on the basis of linear differential equations of increasing order. From 3 to 20 Hz the behavior of the system was best described by a 3rd-order equation, and from 3 to 50 Hz by a 4th-order one. A mechanistic model of the 4th order, featuring tissue compliance (Ct), resistance (Rt) and inertance (It), alveolar gas compressibility (Cg) and airway resistance (Raw), and inertance (Iaw) was developed. Using that model, the following mean values were found: Ct = 2.08–10(-2)1-hPa-1 (1 hPa congruent to 1 cm of water); Rt = 1.10-hPa-1(-1)-s; It = 0.21–10(-2)hPa-1(-1)-s2; Raw = 1.35-hPa-1(-1)-s; Iaw = 2.55–10(-2)hPa-1(-1)-s2. Additional experiments devised to validate the model were reasonably successful, suggesting that the physical meaning attributed to the coefficients was correct. The validity of the assumptions and the physiological meaning of the coefficients are discussed.

Respiratory transfer impedance between 8 and 384 Hz in guinea pigs before and after bronchial challenge

1997 ◽  
Vol 82 (1) ◽  
pp. 172-181 ◽  
Author(s):  
Jamil F. Sobh ◽  
Craig M. Lilly ◽  
Jeffrey M. Drazen ◽  
Andrew C. Jackson
Keyword(s):  
Guinea Pigs ◽  
Airway Resistance ◽  
Element Model ◽  
The Body ◽  
Airway Wall ◽  
Bronchial Challenge ◽  
Transfer Impedance ◽  
Before And After ◽  
Tissue Compliance ◽  
Peripheral Airway

Sobh, Jamil F., Craig M. Lilly, Jeffrey M. Drazen, and Andrew C. Jackson. Respiratory transfer impedance between 8 and 384 Hz in guinea pigs before and after bronchial challenge. J. Appl. Physiol. 82(1): 172–181, 1997.—We report a forced oscillatory technique for noninvasively measuring respiratory transfer impedance (Ztr) between 8 and 384 Hz in guinea pigs. This technique uses a device consisting of two chambers: one surrounding the animal’s head that is used as a plethysmograph to measured flow through the airway opening and the other that surrounds the animal’s body and is used to apply pressure oscillations to the body surface. Ztr was measured in spontaneously breathing awake guinea pigs and while the animals were anesthetized in normal and methacholine-challenged conditions. An eight-element model consisting of an airway compartment separated from a tissue compartment by a shunt gas compression compartment was fit to the data. Anesthesia increased central and peripheral airway resistance and bronchial airway wall compliance by 13, 31, and 44%, respectively, whereas it decreased tissue compliance by 37%. Compared with the unanesthetized condition, the methacholine challenge (20 μg/kg) resulted in an increase in central and peripheral airway resistance (69 and 319%, respectively) and a decrease in bronchial airway wall and tissue compliance (37 and 79%, respectively). This technique is capable of measuring Ztr in anesthetized and awake guinea pigs. Analysis of these data with this eight-element model provides reasonable estimates of airway and tissue parameters.

Nonlinear Analysis of Visual Evoked Potentials Elicited by Color Stimulation

1997 ◽  
Vol 36 (04/05) ◽  
pp. 315-318 ◽  
Author(s):  
K. Momose ◽  
K. Komiya ◽  
A. Uchiyama
Keyword(s):  
Visual System ◽  
Evoked Potentials ◽  
Visual Evoked Potentials ◽  
Normal Subjects ◽  
Second Order ◽  
First Order ◽  
The Relationship ◽  
Perceived Color ◽  
Second Order Nonlinearity ◽  
Visual Evoked

Abstract:The relationship between chromatically modulated stimuli and visual evoked potentials (VEPs) was considered. VEPs of normal subjects elicited by chromatically modulated stimuli were measured under several color adaptations, and their binary kernels were estimated. Up to the second-order, binary kernels obtained from VEPs were so characteristic that the VEP-chromatic modulation system showed second-order nonlinearity. First-order binary kernels depended on the color of the stimulus and adaptation, whereas second-order kernels showed almost no difference. This result indicates that the waveforms of first-order binary kernels reflect perceived color (hue). This supports the suggestion that kernels of VEPs include color responses, and could be used as a probe with which to examine the color visual system.

The Relationship of Root Mean Square Value of Electromyography and Isometric Torque of Quadriceps in Normal Subjects

2016 ◽  
Vol 26 (1) ◽  
pp. 58
Author(s):  
Qiurong XIE ◽  
Zheng JIANG ◽  
Qinglu LUO ◽  
Jie LIANG ◽  
Xiaoling WANG ◽  
...  
Keyword(s):  
Root Mean Square ◽  
Normal Subjects ◽  
Mean Square ◽  
Isometric Torque ◽  
Relationship Of ◽  
The Relationship

Digital twin of the chip formation process

2020 ◽  
pp. 81-86
Author(s):  
Yu.G. Kabaldin ◽  
D.A. Shatagin ◽  
M.S. Anosov ◽  
A.M. Kuz'mishina
Keyword(s):  
Neural Network ◽  
Control System ◽  
Crystal Lattice ◽  
Network Model ◽  
Intelligent Control ◽  
Neural Network Model ◽  
Formation Process ◽  
Chip Formation ◽  
Intelligent Control System ◽  
The Relationship

The formation of chips during the processing of various materials was studied. The relationship between the type of chips, the type of crystal lattice of the material and the number of sliding systems is shown. A neural network model of chip formation is developed, which allows predicting the type of chips. An intelligent control system for the process of chip formation during cutting is proposed. Keywords: chip formation, crystal lattice, neural network model, type of chips. [email protected]

Prediction model for the mechanical properties of compacted poplar powder generated via hot-pressing

BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 4947-4962
Author(s):  
Jin Yan ◽  
Jianan Liu ◽  
Liqiang Zhang ◽  
Zhili Tan ◽  
Haoran Zhang ◽  
...  
Keyword(s):  
Neural Network ◽  
Mechanical Properties ◽  
Network Model ◽  
Process Parameters ◽  
Neural Network Model ◽  
Hot Pressing ◽  
Process Conditions ◽  
Wood Powder ◽  
Single Factor ◽  
The Relationship

The influence of the process parameters on the mechanical properties of compact wood powder generated via hot-pressing was analyzed through a single-factor experiment. The mechanical properties exhibited a nonlinear trend relative to the process conditions of hot-pressed compact wood powder. The relationship models between the process parameters and the mechanical properties for the compact wood powder were established by applying a multiple regression analysis and neural network methods combined with data from an orthogonal array design. A comparison between experimental and predicted results was made to investigate the accuracy of the established models by applying several data groups among the single-factor experiments. The results showed that the accuracy of the neural network model in terms of predicting the mechanical properties was greater compared with the multiple regression model. This demonstrates that the established neural network model had a better prediction performance, and it can accurately map the relationship between the process conditions and the mechanical properties of the compact wood powder.

The Relationship between Lung Volume and Standard Scalar ECG Parameters in Normal Subjects

CHEST Journal ◽  
1989 ◽  
Vol 95 (3) ◽  
pp. 530-534
Author(s):  
John D. Parker ◽  
John E. Fay ◽  
F. James Brennan ◽  
Lutz Forkert
Keyword(s):  
Lung Volume ◽  
Normal Subjects ◽  
The Relationship

The Correlates of Cortical Sulci Atrophy and Central Atrophy in a Cohort of Schizophrenia and Manic Subjects in Nigeria

1995 ◽  
Vol 40 (4) ◽  
pp. 200-204 ◽  
Author(s):  
Abiodun O. Adeyinka ◽  
Jude U. Ohaeri ◽  
Benjamin O. Osuntokun
Keyword(s):  
Brain Atrophy ◽  
Negative Symptoms ◽  
Psychiatric Patients ◽  
Normal Subjects ◽  
Developed Countries ◽  
Clinical Parameters ◽  
Parallel Study ◽  
Healthy Control ◽  
Patient Groups ◽  
The Relationship

The prevalence of brain cortical sulci atrophy and central (subcortical) atrophy among Nigerian psychiatric patients is highlighted and compared with findings from developed countries. The relationship between these indices of brain atrophy and clinical parameters is also examined. Visual ratings of cortical sulci atrophy and central (subcortical) atrophy, assessed on the computed tomography (CT) image console, were compared among 50 patients with schizophrenia, 14 patients with mania and 41 healthy control subjects. The patients with schizophrenia and the patients with mania had a significantly higher prevalence of brain atrophy than normal subjects. Among the patients with schizophrenia, indices of brain atrophy were not significantly associated with disease outcome, and the presence of negative symptoms. In view of the findings from a parallel study of the same patients that psychiatric patient groups showed other evidence of CT abnormalities, the findings of this study indicate that the so-called functional psychiatric states in developing countries — as in developed countries — are probably associated with some diffuse neuropathological process.

Sign in / Sign up

Export Citation Format

Share Document