The problem of stimulation deafness. III. The functional and histological effects of a high-frequency stimulus.

1949 ◽  
Vol 39 (2) ◽  
pp. 238-241 ◽  
Author(s):  
Kendon R. Smith ◽  
Ernest Glen. Wever
Keyword(s):  
High Frequency ◽  
High Frequency Stimulus

The Effect of Neural Entropy during Deep Brain Stimulation of Cortex-Basal Ganglia Network Model.

2021 ◽  
pp. 16089-16097
Author(s):  
Aditya Robin Singh, Vikash Yadav
Keyword(s):  
Deep Brain Stimulation ◽  
Basal Ganglia ◽  
Brain Stimulation ◽  
High Frequency ◽  
Low Frequency ◽  
Field Potentials ◽  
Single Unit Recordings ◽  
High Frequency Stimulus ◽  
Deep Brain ◽  
Stimulation Of

Researchers reported decreased nerve entropy Patients with Parkinson's disease (PD) have abnormalities in their basal ganglia (BG). Studies of local field potentials (LFPs) recorded from the hypothalamus and single unit recordings of GP neurons showed this reduction to be significant. According to this hypothesis, these changes are consistent with changes in the ability of the basal ganglion network to encode PD information. Our deep brain stimulation of cortical basal ganglia (DBS) model includes single LFP recordings and shows how entropy changes during DBS. In addition to the extracellular stimulation of supplied STN fibers and LFP mimetics, which are detected differently on a registered electrode, this model includes osteoclast activation and anti-apoptosis. In the DBS network, the firing pattern fluctuated between high-frequency and low-frequency stimuli, since gp neurons in the network showed a decrease in entropy when a high-frequency stimulus was applied and an increase in entropy when a low-frequency stimulus was applied. Second hand. Changes in neural entropy after DBS have been reported experimentally. The simulation results were consistent

scholarly journals The Mechanisms of Post-Tetanic Potentiation in Cat Soleus and Gastrocnemius Muscles

1964 ◽  
Vol 47 (5) ◽  
pp. 987-1001 ◽  
Author(s):  
Frank G. Standaert
Keyword(s):  
Nerve Terminal ◽  
High Frequency ◽  
Motor Nerve ◽  
Single Stimulus ◽  
Motor Nerve Terminal ◽  
Subsequent Response ◽  
Neural Event ◽  
Post Tetanic Potentiation ◽  
Gastrocnemius Muscles ◽  
High Frequency Stimulus

Post-tetanic potentiation of muscle contraction strength (PTP) occurs in cat soleus and gastrocnemius muscles. However, the mechanisms of potentiation are different in these two muscles. Soleus PTP is predominantly a neural event. The application of a high frequency stimulus to the soleus nerve regularly causes each subsequent response to a single stimulus to become repetitive. This post-tetanic repetitive activity (PTR) originates in the motor nerve terminal and is transmitted to the muscle. Consequently each potentiated soleus contraction is a brief tetanus. In gastrocnemius PTR occurs too infrequently to account for PTP. Furthermore, PTP occurs in curarized directly stimulated gastrocnemius muscles to the same extent as in the indirectly stimulated muscle. In this instance PTP is a muscle phenomenon.

The Microstructure of Steatite (Protoenstatite)

1985 ◽  
Vol 43 ◽  
pp. 236-237
Author(s):  
W. E. Lee ◽  
A. H. Heuer
Keyword(s):  
High Frequency ◽  
Glass Ceramics ◽  
Magnesium Silicate ◽  
Beam Current ◽  
Glassy Matrix ◽  
Angle Of Incidence ◽  
X Ray ◽  
Mechanical And Electrical Properties ◽  
Argon Ions ◽  
High Temperature Polymorph

IntroductionTraditional steatite ceramics, made by firing (vitrifying) hydrous magnesium silicate, have long been used as insulators for high frequency applications due to their excellent mechanical and electrical properties. Early x-ray and optical analysis of steatites showed that they were composed largely of protoenstatite (MgSiO3) in a glassy matrix. Recent studies of enstatite-containing glass ceramics have revived interest in the polymorphism of enstatite. Three polymorphs exist, two with orthorhombic and one with monoclinic symmetry (ortho, proto and clino enstatite, respectively). Steatite ceramics are of particular interest a they contain the normally unstable high-temperature polymorph, protoenstatite.Experimental3mm diameter discs cut from steatite rods (∼10” long and 0.5” dia.) were ground, polished, dimpled, and ion-thinned to electron transparency using 6KV Argon ions at a beam current of 1 x 10-3 A and a 12° angle of incidence. The discs were coated with carbon prior to TEM examination to minimize charging effects.

Simulations of high-resolution images of amorphous silicon films

1986 ◽  
Vol 44 ◽  
pp. 544-545
Author(s):  
G. Y. Fan ◽  
J. M. Cowley
Keyword(s):  
Electron Microscope ◽  
High Frequency ◽  
Fourier Transformation ◽  
Amorphous Materials ◽  
Low Frequency ◽  
Chromatic Aberration ◽  
Structure Information ◽  
Frequency Components ◽  
High Resolution Images ◽  
Spatial Frequency Spectrum

It is well known that the structure information on the specimen is not always faithfully transferred through the electron microscope. Firstly, the spatial frequency spectrum is modulated by the transfer function (TF) at the focal plane. Secondly, the spectrum suffers high frequency cut-off by the aperture (or effectively damping terms such as chromatic aberration). While these do not have essential effect on imaging crystal periodicity as long as the low order Bragg spots are inside the aperture, although the contrast may be reversed, they may change the appearance of images of amorphous materials completely. Because the spectrum of amorphous materials is continuous, modulation of it emphasizes some components while weakening others. Especially the cut-off of high frequency components, which contribute to amorphous image just as strongly as low frequency components can have a fundamental effect. This can be illustrated through computer simulation. Imaging of a whitenoise object with an electron microscope without TF limitation gives Fig. 1a, which is obtained by Fourier transformation of a constant amplitude combined with random phases generated by computer.

SEM image sharpness analysis

1996 ◽  
Vol 54 ◽  
pp. 142-143
Author(s):  
M. T. Postek ◽  
A. E. Vladar
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Quantitative Information ◽  
Primary Electron ◽  
Image Sharpness ◽  
Critical Dimensions ◽  
Sem Image ◽  
Frequency Changes ◽  
Electron Microscopes ◽  
Scanning Electron

Fully automated or semi-automated scanning electron microscopes (SEM) are now commonly used in semiconductor production and other forms of manufacturing. The industry requires that an automated instrument must be routinely capable of 5 nm resolution (or better) at 1.0 kV accelerating voltage for the measurement of nominal 0.25-0.35 micrometer semiconductor critical dimensions. Testing and proving that the instrument is performing at this level on a day-by-day basis is an industry need and concern which has been the object of a study at NIST and the fundamentals and results are discussed in this paper.In scanning electron microscopy, two of the most important instrument parameters are the size and shape of the primary electron beam and any image taken in a scanning electron microscope is the result of the sample and electron probe interaction. The low frequency changes in the video signal, collected from the sample, contains information about the larger features and the high frequency changes carry information of finer details. The sharper the image, the larger the number of high frequency components making up that image. Fast Fourier Transform (FFT) analysis of an SEM image can be employed to provide qualitiative and ultimately quantitative information regarding the SEM image quality.

Real Ear Sound Pressure Levels Developed by Three Portable Stereo System Earphones

1992 ◽  
Vol 1 (4) ◽  
pp. 52-55 ◽  
Author(s):  
Gail L. MacLean ◽  
Andrew Stuart ◽  
Robert Stenstrom
Keyword(s):  
High Frequency ◽  
Sound Pressure ◽  
Low Frequency ◽  
Test System ◽  
Output Frequency ◽  
Frequency Effects ◽  
Adult Men ◽  
Frequency Responses ◽  
Significant Difference ◽  
Sound Pressure Levels

Differences in real ear sound pressure levels (SPLs) with three portable stereo system (PSS) earphones (supraaural [Sony Model MDR-44], semiaural [Sony Model MDR-A15L], and insert [Sony Model MDR-E225]) were investigated. Twelve adult men served as subjects. Frequency response, high frequency average (HFA) output, peak output, peak output frequency, and overall RMS output for each PSS earphone were obtained with a probe tube microphone system (Fonix 6500 Hearing Aid Test System). Results indicated a significant difference in mean RMS outputs with nonsignificant differences in mean HFA outputs, peak outputs, and peak output frequencies among PSS earphones. Differences in mean overall RMS outputs were attributed to differences in low-frequency effects that were observed among the frequency responses of the three PSS earphones. It is suggested that one cannot assume equivalent real ear SPLs, with equivalent inputs, among different styles of PSS earphones.

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