scholarly journals Evaluation of jaw and neck muscle activities while chewing using EMG-EMG transfer function and EMG-EMG coherence function analyses in healthy subjects

2016 ◽  
Vol 160 ◽  
pp. 35-42 ◽  
Author(s):  
Tomohiro Ishii ◽  
Noriyuki Narita ◽  
Hiroshi Endo
Keyword(s):  
Transfer Function ◽  
Healthy Subjects ◽  
Coherence Function ◽  
Neck Muscle

scholarly journals Coordinated features in jaw and neck muscle activities induced by chewing of soft and hard gum in healthy subjects

2021 ◽  
Author(s):  
Tomohiro Ishii ◽  
Noriyuki Narita ◽  
Hiroshi Endo ◽  
Masanobu Wakami ◽  
Masakazu Okubo ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Neck Muscle

scholarly journals Ultrasonography Method of Deep Cervical Muscles and Thickness Measurement Reliability in Cervicogenic Headache and Healthy Subjects:APilot Study

2021 ◽  
Author(s):  
Omolbanin Abaspour ◽  
Mohammad Akbari ◽  
Asghar Rezasoltani
Keyword(s):  
Healthy Subjects ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Muscle Thickness ◽  
Cervicogenic Headache ◽  
Thickness Measurement ◽  
Neck Muscle ◽  
Ultrasound Images ◽  
Intraclass Correlation Coefficients ◽  
Linear Probe

Introduction: In Cervicogenic Headache (CGH), motor control of muscles is impaired and deep upper neck muscles (extensor and flexor muscles) become atrophied. In this research, thickness measurement of Longus Capitis (LCap), Rectus Capitis Posterior Major (RCPM), and Obliquus Capitis Superior (OCS) muscles were conducted and intra-rater reliability of the thickness measurement of these muscles was assessed in CGH and healthy subjects. Materials and Methods: Twenty subjects, including 10 healthy subjects (19-32 years old) and 10 CGH patients (20-35 years old) participated in this study. LCap thickness was measured at the level of C3-C4 in the supine position and posterior muscles (RCPM and OCS) thickness at the C1-C2 level in the sitting position. All ultrasound images were captured by a linear probe with a 50-mm footprint in B mode option and frequency range of 9-12 Hz. Intraclass Correlation Coefficients (ICC), Standard Error Of Measurement (SEM), and the Smallest Detectable Difference (SDD) were calculated for data analysis. Results: The ICC for thickness measurement of LCap was from 0.70 to 0.91 (good to excellent), for RCPM thickness was from 0.69 to 0.94 and for OCS muscle thickness was from 0.87 to 0.98. SEM values for LCap were between 0.08 and 0.25 and the SDD values between 0.22 and 0.71. SEM values for RCPM were between 0.22 and 0.43 and these values were reported for OCS muscle between 0.19 and 0.45. Conclusion: The results indicated that the presented position and the level of ultrasonography in this study are appropriate and ultrasound is a reliable tool to measure the deep upper neck muscle thickness in CGH and healthy subjects.

scholarly journals Autonomic control of cardiorespiratory coupling in healthy subjects under moderate physical exercises

2019 ◽  
Vol 8 (4) ◽  
Author(s):  
Anton R. Kiselev ◽  
Ekaterina I. Borovkova ◽  
Margarita A. Simonyan ◽  
Yuri M. Ishbulatov ◽  
Artak Yu. Ispiryan ◽  
...  
Keyword(s):  
Physical Activity ◽  
Heart Rate ◽  
Healthy Subjects ◽  
Coherence Function ◽  
Peripheral Circulation ◽  
Moderate Physical Activity ◽  
Rr Intervals ◽  
Phase Dynamics ◽  
Physical Exercises ◽  
Directional Coupling

Aim of the study is to apply the analysis of phase dynamics to investigation of the coupling patterns between heart rate variability, respiration and peripheral circulation in healthy subjects at rest and after moderate physical exercises. Material and Methods ― 30-minutes electrocardiogram (ECG), photoplethysmogram (PPG) and respiration records were obtained from healthy subjects aged 22±2 (mean ± standard deviation) before and after active Martine Kushelevsky test (20 squats in 30 seconds). The coherence function was estimated between all the signals from each subject, and the phase dynamics modeling was used to detect the directional coupling in high-frequency (HF; 0.14-0.40 Hz) and low-frequency ranges (LF; 0.04-0.14 Hz). Results ― At rest (before the physical activity) no statistically significant couplings were detected between the HF rhythms of respiration and heart rate (RR intervals). For the HF rhythms in respiration and PPG, the influence respirationPPG was detected. No couplings were detected between the LF rhythms. After the moderate physical exercise, predominant direction of the influence was RR intervals  PPG in the LF range and both RR intervals  respiration and PPG  respiration in the HF range. The influence PPG  respiration was delayed by several seconds. Conclusion ― adaptation to the moderate physical activity has led to the decrease in the overall coherence and changes in patterns of directional coupling between the LF and HF rhythms in respiration, heart rate and peripheral circulation. The obtained results confirm nonlinearity and complexity of the coupling patterns in cardiovascular system.

Three-dimensional effects on the transfer function of a rectangular-section body in turbulent flow

2019 ◽  
Vol 872 ◽  
pp. 348-366 ◽  
Author(s):  
Yang Yang ◽  
Mingshui Li ◽  
Haili Liao
Keyword(s):  
Transfer Function ◽  
Turbulent Flow ◽  
Transfer Functions ◽  
Coherence Function ◽  
Three Dimensional ◽  
Accurate Estimation ◽  
Rectangular Section ◽  
Dimensional Effects ◽  
Aspect Ratios ◽  
Strip Theory

This paper investigates the influence of three-dimensional effects on the transfer function of a rectangular-section body in turbulent flow. The dimensionless factor $\unicode[STIX]{x1D713}$, as derived by Li et al. (J. Fluid Mech., vol. 847, 2018, pp. 768–785), is adapted to evaluate this influence. The calculation of $\unicode[STIX]{x1D713}$ requires the spanwise influence term. For this purpose, an adapted form of the lift coherence function is derived, enabling the use of the measured lift coherence for the estimation of the spanwise influence term. Three rectangular models with different cross-sections (chord-to-depth ratios of 3, 5 and 10) are chosen for testing, and a NACA 0015 airfoil model is tested for comparison. Using the measured spanwise influence terms, the dimensionless factors of these models are then numerically calculated under different ratios of the turbulent integral scale to the chord $\unicode[STIX]{x1D6FE}$ and aspect ratios $\unicode[STIX]{x1D703}$. It is shown that the dimensionless factors of the rectangular models increase as $\unicode[STIX]{x1D6FE}$ and $\unicode[STIX]{x1D703}$ increase, which are similar to the dimensionless factor of the airfoil model. If $\unicode[STIX]{x1D6FE}$ and $\unicode[STIX]{x1D703}$ have suitable values, the strip theory could be applicable to the rectangular-section body. It is also found that the dimensionless factors of all the rectangular models are larger than the dimensionless factor of the airfoil model under the same parameters. The smaller the chord-to-depth ratio is, the larger the dimensionless factor is. Using the strip theory to calculate the lift response of the rectangular-section body may provide more accurate estimation. Additionally, the one-wavenumber transfer functions of these models are determined under the consideration of the three-dimensional effects. The results show that the experimental transfer functions of the rectangular models cannot be captured by the Sears function. They are larger than the Sears function at lower frequencies, while falling at a faster rate as the frequency increases. For bluff bodies with separated flow, the modified transfer function presented here appears to be an appropriate approach.

scholarly journals Transfer function analysis of dynamic cerebral autoregulation in humans

1998 ◽  
Vol 274 (1) ◽  
pp. H233-H241 ◽  
Author(s):  
Rong Zhang ◽  
Julie H. Zuckerman ◽  
Cole A. Giller ◽  
Benjamin D. Levine
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Transfer Function ◽  
Arterial Pressure ◽  
Cerebral Autoregulation ◽  
Coherence Function ◽  
Frequency Range ◽  
Cuff Deflation ◽  
Transfer Function Analysis ◽  
Acute Hypotension

To test the hypothesis that spontaneous changes in cerebral blood flow are primarily induced by changes in arterial pressure and that cerebral autoregulation is a frequency-dependent phenomenon, we measured mean arterial pressure in the finger and mean blood flow velocity in the middle cerebral artery (V˙MCA) during supine rest and acute hypotension induced by thigh cuff deflation in 10 healthy subjects. Transfer function gain, phase, and coherence function between changes in arterial pressure andV˙MCA were estimated using the Welch method. The impulse response function, calculated as the inverse Fourier transform of this transfer function, enabled the calculation of transient changes inV˙MCA during acute hypotension, which was compared with the directly measured change in V˙MCA during thigh cuff deflation. Beat-to-beat changes inV˙MCA occurred simultaneously with changes in arterial pressure, and the autospectrum of V˙MCA showed characteristics similar to arterial pressure. Transfer gain increased substantially with increasing frequency from 0.07 to 0.20 Hz in association with a gradual decrease in phase. The coherence function was >0.5 in the frequency range of 0.07–0.30 Hz and <0.5 at <0.07 Hz. Furthermore, the predicted change inV˙MCA was similar to the measuredV˙MCA during thigh cuff deflation. These data suggest that spontaneous changes inV˙MCA that occur at the frequency range of 0.07–0.30 Hz are related strongly to changes in arterial pressure and, furthermore, that short-term regulation of cerebral blood flow in response to changes in arterial pressure can be modeled by a transfer function with the quality of a high-pass filter in the frequency range of 0.07–0.30 Hz.

Difference between neck muscle vibration and gluteus muscle vibration on standing balance in healthy subjects

2019 ◽  
Vol 49 (6) ◽  
pp. 433
Author(s):  
Karim Jamal ◽  
Armel Cretual ◽  
Sébastien Cordillet ◽  
Chloé Rousseau ◽  
Stéphanie Leplaideur ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Standing Balance ◽  
Neck Muscle ◽  
Muscle Vibration ◽  
Neck Muscle Vibration ◽  
Gluteus Muscle

Reflex Responses in Upper Limb Muscles to Cutaneous Stimuli

1993 ◽  
Vol 20 (04) ◽  
pp. 271-278 ◽  
Author(s):  
R. Chen
Keyword(s):  
Stimulus Intensity ◽  
Upper Limb ◽  
Healthy Subjects ◽  
Voluntary Contraction ◽  
Cutaneous Reflexes ◽  
Focal Lesions ◽  
Normal Ranges ◽  
Conduction Velocities ◽  
Limb Muscles ◽  
Biphasic Responses

ABSTRACT:Cutaneous reflexes in the upper limb were elicited by stimulating digital nerves and recorded by averaging rectified EMG from proximal and distal upper limb muscles during voluntary contraction. Distal muscles often showed a triphasic response: an inhibition with onset about 50 ms (Il) followed by a facilitation with onset about 60 ms (E2) followed by another inhibition with onset about 80 ms (12). Proximal muscles generally showed biphasic responses beginning with facilitation or inhibition with onset at about 40 ms. Normal ranges for the amplitude of these components were established from recordings on 22 arms of 11 healthy subjects. An attempt was made to determine the alterent fibers responsible for the various components by varying the stimulus intensity, by causing ischemic block of larger fibers and by estimating the afferent conduction velocities. The central pathways mediating these reflexes were examined by estimating central delays and by studying patients with focal lesions

Radiation Damage of Support Films

1981 ◽  
Vol 39 ◽  
pp. 28-29
Author(s):  
H.A. Cohen ◽  
W. Chiu
Keyword(s):  
Transfer Function ◽  
Low Temperatures ◽  
Carbon Support ◽  
Contrast Transfer Function ◽  
Electron Dose ◽  
Imaging Parameters ◽  
Negative Stain ◽  
Phase Corrections ◽  
Two Parameters ◽  
Medium Dose

The goal of imaging the finest detail possible in biological specimens leads to contradictory requirements for the choice of an electron dose. The dose should be as low as possible to minimize object damage, yet as high as possible to optimize image statistics. For specimens that are protected by low temperatures or for which the low resolution associated with negative stain is acceptable, the first condition may be partially relaxed, allowing the use of (for example) 6 to 10 e/Å2. However, this medium dose is marginal for obtaining the contrast transfer function (CTF) of the microscope, which is necessary to allow phase corrections to the image. We have explored two parameters that affect the CTF under medium dose conditions.Figure 1 displays the CTF for carbon (C, row 1) and triafol plus carbon (T+C, row 2). For any column, the images to which the CTF correspond were from a carbon covered hole (C) and the adjacent triafol plus carbon support film (T+C), both recorded on the same micrograph; therefore the imaging parameters of defocus, illumination angle, and electron statistics were identical.

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