Total respiratory input and transfer impedances in humans

1985 ◽  
Vol 59 (2) ◽  
pp. 492-501 ◽  
Author(s):  
R. Peslin ◽  
C. Duvivier ◽  
C. Gallina
Keyword(s):  
Resonant Frequency ◽  
Frequency Dependence ◽  
Imaginary Part ◽  
Airway Resistance ◽  
The Real ◽  
Tissue Resistance ◽  
Gas Compressibility ◽  
Healthy Males

Total respiratory input (Zrs,in) and transfer (Zrs,tr) impedances were obtained from 4 to 30 Hz in 10 healthy males by simultaneously measuring mouth and chest flow while applying pseudo-random pressure variations at the mouth. Compared with Zrs,in, the real part of Zrs,tr was larger up to 10 Hz but exhibited a much stronger negative frequency dependence. The imaginary part was larger at all frequencies, with a resonant frequency (fn) at 6.0 +/- 0.8 Hz compared with 8.2 +/- 2.9 Hz for Zrs,in. The two impedances were analyzed with a model featuring airway resistance and inertance, alveolar gas compressibility, and tissue resistance, inertance, and compliance. A good fit was generally obtained but, in most cases, with a different partitioning of resistance between airway and tissue for Zrs,in and Zrs,tr. The data were also used to compute separately airway and tissue (Zt) impedances. In most subjects Zt could not be properly fitted with a simple resistance-inertance-compliance unit and was consistent with a slow (fn = 7.4 +/- 2.3 Hz) overdamped compartment in parallel with a fast (fn = 37.1 +/- 5.6 Hz) underdamped one.

Partitioning airway and lung tissue resistances in humans: effects of bronchoconstriction

1997 ◽  
Vol 82 (5) ◽  
pp. 1531-1541 ◽  
Author(s):  
David W. Kaczka ◽  
Edward P. Ingenito ◽  
Bela Suki ◽  
Kenneth R. Lutchen
Keyword(s):  
Frequency Dependence ◽  
Lung Tissue ◽  
Airway Resistance ◽  
Broad Band ◽  
Airway Wall ◽  
Lung Elastance ◽  
Tissue Resistance ◽  
Lung Resistance ◽  
High Doses ◽  
Total Lung Resistance

Kaczka, David W., Edward P. Ingenito, Bela Suki, and Kenneth R. Lutchen. Partitioning airway and lung tissue resistances in humans: effects of bronchoconstriction. J. Appl. Physiol. 82(5): 1531–1541, 1997.—The contribution of airway resistance (Raw) and tissue resistance (Rti) to total lung resistance (R l ) during breathing in humans is poorly understood. We have recently developed a method for separating Raw and Rti from measurements of Rland lung elastance (El) alone. In nine healthy, awake subjects, we applied a broad-band optimal ventilator waveform (OVW) with energy between 0.156 and 8.1 Hz that simultaneously provides tidal ventilation. In four of the subjects, data were acquired before and during a methacholine (MCh)-bronchoconstricted challenge. The Rland Eldata were first analyzed by using a model with a homogeneous airway compartment leading to a viscoelastic tissue compartment consisting of tissue damping and elastance parameters. Our OVW-based estimates of Raw correlated well with estimates obtained by using standard plethysmography and were responsive to MCh-induced bronchoconstriction. Our data suggest that Rti comprises ∼40% of total Rlat typical breathing frequencies, which corresponds to ∼60% of intrathoracic Rl. During mild MCh-induced bronchoconstriction, Raw accounts for most of the increase in Rl. At high doses of MCh, there was a substantial increase in Rlat all frequencies and in El at higher frequencies. Our analysis showed that both Raw and Rti increase, but most of the increase is due to Raw. The data also suggest that widespread peripheral constriction causes airway wall shunting to produce additional frequency dependence in El.

Confidence intervals of respiratory mechanical properties derived from transfer impedance

1991 ◽  
Vol 70 (6) ◽  
pp. 2432-2438 ◽  
Author(s):  
M. Rotger ◽  
R. Peslin ◽  
E. Oostveen ◽  
C. Gallina
Keyword(s):  
Confidence Intervals ◽  
Healthy Subjects ◽  
Airway Resistance ◽  
Intraindividual Variability ◽  
Biological Variability ◽  
Short Term ◽  
Transfer Impedance ◽  
Tissue Resistance ◽  
Gas Compressibility ◽  
Single Set

Short-term intraindividual variability of the parameters derived from respiratory transfer impedance (Ztr) measured from 4 to 32 Hz was studied in 10 healthy subjects. The corresponding 95% confidence intervals (CIo) were compared with those computed from a single set of data (CIL) according to Lutchen and Jackson (J. Appl. Physiol. 62: 403-413, 1987). Ztr was analyzed with the six-coefficient model of DuBois et al. (J. Appl. Physiol. 8: 587-594, 1956), which includes airway resistance (Raw) and inertance (Iaw), tissue resistance (Rti), inertance (Iti), and compliance (Cti), and alveolar gas compressibility (Cg). The lowest variability was seen for Iaw (CIo = 11.1%), closely followed by Raw (14.3%) and Cti (14.8%), and the largest for Rti and Iti (24.6 and 93.6%, respectively). Using a simpler model, where Iti was excluded, significantly decreased the variability of Iaw (P less than 0.01) and Rti (P less than 0.05) but was responsible for a systematic decrease of Raw and Iaw and increase of Rti. Except for Raw with both models and Iaw with the simpler model, CIL was greater than CIo. Whatever the model, a high correlation between both sets of confidence intervals was found for Rti and Iaw, whereas no correlation was seen for Raw. This suggests that the variability of the former coefficients mainly reflects experimental noise, whereas that of the latter is largely due to biological variability.

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.

scholarly journals Complex q-Rung Orthopair Fuzzy Aggregation Operators and Their Applications in Multi-Attribute Group Decision Making

Information ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 5 ◽  
Author(s):  
Liu ◽  
Mahmood ◽  
Ali
Keyword(s):  
Decision Making ◽  
Fuzzy Sets ◽  
Imaginary Part ◽  
Group Decision Making ◽  
Group Decision ◽  
Aggregation Operators ◽  
Uncertain Information ◽  
Membership Degree ◽  
The Real ◽  
Complex Valued

In this manuscript, the notions of q-rung orthopair fuzzy sets (q-ROFSs) and complex fuzzy sets (CFSs) are combined is to propose the complex q-rung orthopair fuzzy sets (Cq-ROFSs) and their fundamental laws. The Cq-ROFSs are an important way to express uncertain information, and they are superior to the complex intuitionistic fuzzy sets and the complex Pythagorean fuzzy sets. Their eminent characteristic is that the sum of the qth power of the real part (similarly for imaginary part) of complex-valued membership degree and the qth power of the real part (similarly for imaginary part) of complex-valued non‐membership degree is equal to or less than 1, so the space of uncertain information they can describe is broader. Under these environments, we develop the score function, accuracy function and comparison method for two Cq-ROFNs. Based on Cq-ROFSs, some new aggregation operators are called complex q-rung orthopair fuzzy weighted averaging (Cq-ROFWA) and complex q-rung orthopair fuzzy weighted geometric (Cq-ROFWG) operators are investigated, and their properties are described. Further, based on proposed operators, we present a new method to deal with the multi‐attribute group decision making (MAGDM) problems under the environment of fuzzy set theory. Finally, we use some practical examples to illustrate the validity and superiority of the proposed method by comparing with other existing methods.

One Method to Construct the S-Box Based on Improved Chaos Map

2014 ◽  
Vol 651-653 ◽  
pp. 2164-2167
Author(s):  
Hang Zhang ◽  
Xiao Jun Tong
Keyword(s):  
Imaginary Part ◽  
Logistic Map ◽  
Block Ciphers ◽  
Mandelbrot Set ◽  
New Method ◽  
Hénon Map ◽  
Henon Map ◽  
The Real

Many methods of constructing S-box often adopt the classical chaotic equations. Yet study found that some of the chaotic equations exists drawbacks. Based on that, this paper proposed a new method to generate S-Box by improving the Logistic map and Henon map, and combining the real and imaginary part of complex produced by the Mandelbrot set. By comparing with several other S-boxes proposed previously, the results show the S-box here has better cryptographic properties. So it has a good application prospect in block ciphers.

Time course of respiratory mechanics during histamine challenge in the dog

1992 ◽  
Vol 73 (6) ◽  
pp. 2643-2647 ◽  
Author(s):  
A. M. Lauzon ◽  
G. Dechman ◽  
J. H. Bates
Keyword(s):  
Time Course ◽  
Airway Resistance ◽  
Respiratory Mechanics ◽  
Smooth Muscles ◽  
Atropine Sulfate ◽  
Mechanical Parameters ◽  
Peripheral Airways ◽  
Tissue Resistance ◽  
Histamine Challenge ◽  
Tissue Elastance

We studied the dynamics of respiratory mechanical parameters in anesthetized tracheostomized paralyzed dogs challenged with a bolus of histamine injected either venously (venous group) or arterially (arterial group). The venous group was further divided into two groups: the first was bilaterally vagotomized and received hexamethonium bromide (denervated group), and the second also received atropine sulfate (atropine group). In the venous group, tissue resistance (Rti) and tissue elastance (Eti) increased biphasically, whereas airway resistance was monophasic and synchronized with the second rise of the tissue parameters. In the arterial group, Rti, Eti, and airway resistance increased synchronously. The denervated and atropine groups showed dynamics similar to those of the venous group. We postulate that the first phase observed in Rti and Eti in the venous group is due to constriction of the smooth muscles of the peripheral airways and blood vessels distorting the parenchyma. The second and larger phase is then due to histamine reaching the bronchial circulation and constricting the central airways, again distorting the parenchyma. The results from the arterial group support this hypothesis, whereas those from the denervated group ascertain that none of the phases observed in the venous group was due to nervous reflexes.

scholarly journals GAP EQUATION IN SCALAR FIELD THEORY AT FINITE TEMPERATURE

1999 ◽  
Vol 14 (04) ◽  
pp. 257-266
Author(s):  
KRISHNENDU MUKHERJEE
Keyword(s):  
Field Theory ◽  
Perturbation Theory ◽  
Scalar Field ◽  
Imaginary Part ◽  
Finite Temperature ◽  
Thermal Mass ◽  
Scalar Field Theory ◽  
Gap Equation ◽  
The Real

We investigate the two-loop gap equation for the thermal mass of hot massless g2ϕ4 theory and find that the gap equation itself has a nonzero finite imaginary part. This implies that it is not possible to find the real thermal mass as a solution of the gap equation beyond g2 order in perturbation theory. We have solved the gap equation and obtained the real and imaginary parts of the thermal mass which are correct up to g4 order in perturbation theory.

FACE REPRESENTATION WITH GRADIENT ORIENTATIONS AND EULER MAPPING: APPLICATION TO FACE RECOGNITION

2014 ◽  
Vol 28 (08) ◽  
pp. 1456014 ◽  
Author(s):  
ZHAOKUI LI ◽  
LIXIN DING ◽  
YAN WANG ◽  
JINRONG HE
Keyword(s):  
Face Recognition ◽  
Imaginary Part ◽  
Feature Vector ◽  
Low Frequency ◽  
Subspace Learning ◽  
The Real ◽  
Face Representation ◽  
Central Pixel ◽  
Low Dimensional ◽  
Two Stages

This paper proposes a simple, yet very powerful local face representation, called the Gradient Orientations and Euler Mapping (GOEM). GOEM consists of two stages: gradient orientations and Euler mapping. In the first stage, we calculate gradient orientations of a central pixel and get the corresponding orientation representations by performing convolution operator. These representation results display spatial locality and orientation properties. To encompass different spatial localities and orientations, we concatenate all these representation results and derive a concatenated orientation feature vector. In the second stage, we define an explicit Euler mapping which maps the space of the concatenated orientation into a complex space. For a mapping image, we find that the imaginary part and the real part characterize the high frequency and the low frequency components, respectively. To encompass different frequencies, we concatenate the imaginary part and the real part and derive a concatenated mapping feature vector. For a given image, we use the two stages to construct a GOEM image and derive an augmented feature vector which resides in a space of very high dimensionality. In order to derive low-dimensional feature vector, we present a class of GOEM-based kernel subspace learning methods for face recognition. These methods, which are robust to changes in occlusion and illumination, apply the kernel subspace learning model with explicit Euler mapping to an augmented feature vector derived from the GOEM representation of face images. Experimental results show that our methods significantly outperform popular methods and achieve state-of-the-art performance for difficult problems such as illumination and occlusion-robust face recognition.

scholarly journals Stiffness of sphere–plate contacts at MHz frequencies: dependence on normal load, oscillation amplitude, and ambient medium

2015 ◽  
Vol 6 ◽  
pp. 845-856 ◽  
Author(s):  
Jana Vlachová ◽  
Rebekka König ◽  
Diethelm Johannsmann
Keyword(s):  
Imaginary Part ◽  
Coulomb Friction ◽  
Ambient Medium ◽  
Normal Load ◽  
Contact Stiffness ◽  
Oscillation Amplitude ◽  
Partial Slip ◽  
Squeeze Flow ◽  
Frictional Stress ◽  
The Real

The stiffness of micron-sized sphere–plate contacts was studied by employing high frequency, tangential excitation of variable amplitude (0–20 nm). The contacts were established between glass spheres and the surface of a quartz crystal microbalance (QCM), where the resonator surface had been coated with either sputtered SiO2 or a spin-cast layer of poly(methyl methacrylate) (PMMA). The results from experiments undertaken in the dry state and in water are compared. Building on the shifts in the resonance frequency and resonance bandwidth, the instrument determines the real and the imaginary part of the contact stiffness, where the imaginary part quantifies dissipative processes. The method is closely analogous to related procedures in AFM-based metrology. The real part of the contact stiffness as a function of normal load can be fitted with the Johnson–Kendall–Roberts (JKR) model. The contact stiffness was found to increase in the presence of liquid water. This finding is tentatively explained by the rocking motion of the spheres, which couples to a squeeze flow of the water close to the contact. The loss tangent of the contact stiffness is on the order of 0.1, where the energy losses are associated with interfacial processes. At high amplitudes partial slip was found to occur. The apparent contact stiffness at large amplitude depends linearly on the amplitude, as predicted by the Cattaneo–Mindlin model. This finding is remarkable insofar, as the Cattaneo–Mindlin model assumes Coulomb friction inside the sliding region. Coulomb friction is typically viewed as a macroscopic concept, related to surface roughness. An alternative model (formulated by Savkoor), which assumes a constant frictional stress in the sliding zone independent of the normal pressure, is inconsistent with the experimental data. The apparent friction coefficients slightly increase with normal force, which can be explained by nanoroughness. In other words, contact splitting (i.e., a transport of shear stress across many small contacts, rather than a few large ones) can be exploited to reduce partial slip.

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