scholarly journals Determination of the frequency response of isometric soleus muscle in the cat using random nerve stimulation

1973 ◽  
Vol 229 (2) ◽  
pp. 275-296 ◽  
Author(s):  
Allan Mannard ◽  
Richard B. Stein
Keyword(s):  
Frequency Response ◽  
Soleus Muscle ◽  
Nerve Stimulation

scholarly journals The results of calculated and experimental determination of the frequency response of a mechanical system with gaps

2019 ◽  
Vol 25 ◽  
pp. 20-25
Author(s):  
Dmitry Nasonov ◽  
Mikhail Leontiev ◽  
Vladimir Raevsky ◽  
Anzhelika Volkhonskaya
Keyword(s):  
Frequency Response ◽  
Experimental Determination ◽  
Mechanical System

scholarly journals Quantitative determination of Ca2+-dependent Mg2+-ATPase from sarcoplasmic reticulum in muscle biopsies

1989 ◽  
Vol 260 (2) ◽  
pp. 443-448 ◽  
Author(s):  
M E Everts ◽  
J P Andersen ◽  
T Clausen ◽  
O Hansen
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Soleus Muscle ◽  
Human Subjects ◽  
Vastus Lateralis ◽  
Total Concentration ◽  
Vastus Lateralis Muscle ◽  
Lateralis Muscle ◽  
32P Incorporation ◽  
Muscle Biopsies

The possibility of quantifying the total concentration of Ca2+-dependent Mg2+-ATPase of sarcoplasmic reticulum was investigated by measurement of the Ca2+-dependent steady-state phosphorylation from [gamma-32P]ATP and the Ca2+-dependent 3-O-methylfluorescein phosphatase (3-O-MFPase) activity in crude muscle homogenates. The Ca2+-dependent phosphorylation at 0 degree C (mean +/- S.E.) was 40.0 +/- 2.5 (n = 6) and 6.2 +/- 0.7 (n = 4) nmol/g wet wt. in rat extensor digitorum longus (EDL) and soleus muscle, respectively (P less than 0.001). The Ca2+-dependent 3-O-MFPase activity at 37 degrees C was 1424 +/- 238 (n = 6) and 335 +/- 56 (n = 4) nmol/min per g wet wt. in rat EDL and soleus muscle, respectively (P less than 0.01). The molecular activity calculated from these measurements amounted to 35 +/- 5 min-1 (n = 6) and 55 +/- 10 min-1 (n = 4) for EDL and soleus muscle respectively. These values were not different from the molecular activity calculated for purified Ca2+-ATPase (36 min-1). The Ca2+-dependent 32P incorporation in soleus muscle decreased in the order mice greater than rats greater than guinea pigs. In EDL muscles from hypothyroid rats at a 30% reduction of the Ca2+-dependent phosphorylation was observed. The Ca2+-dependent phosphorylation in vastus lateralis muscle from three human subjects amounted to 4.5 +/- 0.8 nmol/g wet wt. It is concluded that measurement of the Ca2+-dependent phosphorylation allows rapid and reproducible quantification of the concentration of Ca2+-dependent Mg2+-ATPase of sarcoplasmic reticulum. Since only 20-60 mg of tissue is required for the measurements, the method can also be used for biopsies obtained in clinical studies.

Frequency response characteristic of sympathetic-mediated vasomotor waves in conscious rats

1996 ◽  
Vol 271 (4) ◽  
pp. H1416-H1422 ◽  
Author(s):  
H. M. Stauss ◽  
K. C. Kregel
Keyword(s):  
Blood Pressure ◽  
Nervous System ◽  
Sympathetic Nervous System ◽  
Frequency Response ◽  
Arterial Blood Pressure ◽  
Nerve Stimulation ◽  
Splanchnic Nerve ◽  
Conscious Rats ◽  
Arterial Blood ◽  
Sympathetic Nervous

Power spectrum analysis of arterial blood pressure (BP) and heart rate (HR) has been used to investigate autonomic nervous system activity. Sympathetic-mediated vasomotor tone has been attributed to the BP power at frequencies between 0.05 and 0.15 Hz in humans and dogs and between 0.2 and 0.8 Hz in rats. In contrast, it has been suggested that the sympathetic nervous system is too sluggish to transmit frequencies higher than 0.017 Hz in dogs. Thus we investigated the frequency-response characteristics of the transmission of peripheral sympathetic nerve discharge to peripheral vascular resistance and arterial blood pressure in conscious rats. Eleven rats were instrumented with arterial catheters, nerve electrodes on the sympathetic splanchnic nerve, and flow probes on the superior mesenteric artery. The splanchnic nerve was cut proximal to the electrode to avoid afferent nerve stimulation. The next day the nerve was stimulated at frequencies of 0.05, 0.1, 0.2, 0.5, 1.0, and 2.0 Hz while mesenteric blood flow, BP, and HR were recorded in conscious rats. Mesenteric resistance (MR) was calculated off-line. Nerve stimulation at 0.05, 0.1, 0.2, 0.5, and 1.0 Hz significantly increased the power in MR at these respective frequencies. The greatest response was found between 0.2 and 0.5 Hz. These oscillations in MR were translated to oscillations in BP, but not in HR. Nerve stimulation on the second day, when the nerve was degenerated, did not elicit oscillations in MR or BP. We conclude that the peripheral sympathetic nervous system in rats can transmit signals at frequencies higher than those traditionally assigned to sympathetic vasomotor activity in several species, including humans, and may even overlap with the respiration-related high-frequency range.

scholarly journals Frequency Response Quality Index for Assessing the Mechanical Condition of Transformer Windings

Energies ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 29 ◽  
Author(s):  
Eugeniusz Kornatowski ◽  
Szymon Banaszak
Keyword(s):  
Frequency Response ◽  
Quality Index ◽  
Response Analysis ◽  
Test Results ◽  
Response Curves ◽  
Response Measurement ◽  
Response Quality ◽  
Mechanical Condition ◽  
Measurement Results

Frequency response analysis (FRA) is a popular method for assessing a transformer’s mechanical condition. The paper proposes a new method for interpreting the frequency response measurement results. The currently used numerical indices only give one value, which may be misleading in the analysis, while the proposed frequency response quality index (FRQI) tool analyses three separate features in the whole frequency range. The applied numerical calculations technique allows for estimations of not only the values of the average quality indices, but also locally for given frequency ranges of the analysed spectrum. It allows for determination of the problems that can be found in the active part of a transformer. The presented results come from three transformers, representing cases of typical faults. Two of them are from industry, while one was used for deformational tests in laboratory conditions. The proposed FRQI method showed its usefulness in FRA test results analysis and may be introduced into the automated assessment of such data. Each of the component parameters is sensitive to other types of differences observed between the compared frequency response curves, and may be used as a good quality detection tool.

Determination of head conductivity frequency response in vivo with optimized EIT-EEG

NeuroImage ◽  
2016 ◽  
Vol 127 ◽  
pp. 484-495 ◽  
Author(s):  
Juhani Dabek ◽  
Konstantina Kalogianni ◽  
Edwin Rotgans ◽  
Frans C.T. van der Helm ◽  
Gert Kwakkel ◽  
...  
Keyword(s):  
Frequency Response

Validation of improved recording site to measure phrenic conduction from surface electrodes in humans

2002 ◽  
Vol 92 (3) ◽  
pp. 967-974 ◽  
Author(s):  
Eric Verin ◽  
Christian Straus ◽  
Alexandre Demoule ◽  
Philippe Mialon ◽  
Jean-Philippe Derenne ◽  
...  
Keyword(s):  
Nerve Stimulation ◽  
Phrenic Nerve ◽  
Magnetic Stimulation ◽  
Conduction Time ◽  
Phrenic Nerve Stimulation ◽  
Recording Site ◽  
Serratus Anterior ◽  
Surface Electrodes ◽  
Phrenic Nerves

Phrenic nerve stimulation, electrical (ES) or from cervical magnetic stimulation (CMS), allows one to assess the diaphragm contractile properties and the conduction time of the phrenic nerve (PNCT) through recording of an electromyographic response, traditionally by using surface electrodes. Because of the coactivation of extradiaphragmatic muscles, signal contamination can jeopardize the determination of surface PNCTs. To address this, we compared PNCTs with ES and CMS from surface and needle diaphragm electrodes in five subjects (10 phrenic nerves). At a modified recording site, lower and more anterior than usual (lowest accessible intercostal space, costochondral junction) with electrodes 2 cm apart, surface and needle PNCTs were similar (CMS: 6.0 ± 0.25 ms surface vs. 6.2 ± 0.13 ms needle, not significant). Electrodes recording the activity of the most likely sources of signal contamination, i.e., the serratus anterior and pectoralis major, showed distinct responses from that of the diaphragm, their earlier occurrence strongly arguing against contamination. With ES and CMS, apparently uncontaminated signals could be consistently recorded from surface electrodes.

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