• The Korean Journal of Physiology
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• v.6 no.2
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• pp.31-37
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• 1972

The right cervical vagus nerve was electrically stimulated for 30 sec, and 30 minutes recording cardiac rate responses and electrocardiogram. The main purposes of the present experiment are to determine effect of stimulation frequency on the maintenance of cardiac rate responses and to determine recovery time of sinus rhythm after asystole period followed by idioventricular rhythm during prolonged electrical stimulation of the vagus, and the optimal stimulation parameters for vagal stimulation were studied as well. The results obtained are summarized as follows: 1. The maximum negative chrontropic responses were obtained with the following ranges of electrical parameters. Intensity: 3V-7V, Frequency: 20/sec-60/sec, and pulse duration: 5 msec-20 msec. 2. Compared with the responses from sympathetic effectors, cardiac rate responses to electrical stimulation of vagus nerve were well maintained with all stimulation frequencies. 3. At all stimulation frequencies except 20/sec, sinus node started to take over primary pacemaker activity when cardiac rates were restored to about 38-40/min. 4. It was indicated that upper limit of idioventricular rhythm does not exceed 38-40/min. 5. With the stimulation parameter set of 20/sec-5 msec-3 V, sinus rhythm did not appear during 30 minutes of stimulation period. Therefore, this electrical parameter set appears to be optimal for elicitation of prolonged and maximum cardiac rate responses by vagal stimulation.

• Physical Therapy Rehabilitation Science
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• v.11 no.4
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• pp.409-413
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• 2022

Objective: This study aims to compare the range of motion of the joints by applying the contraction and relaxation techniques used in manual therapy as electrical stimulation treatment. Based on this, we would like to propose the possibility of using motor nerve electrical stimulation therapy for musculoskeletal physical therapy. Design: Single-arm interventional study Methods: Active and passive straight leg raising tests were performed on 20 healthy men and women in their 20s to measure the angle of hip joint flexion. Then, the electrical stimulation time was set to 10 seconds and 5 seconds of rest, and motor nerve electrical stimulation of 1 Hz was applied with the maximum strength that could withstand the hamstring muscles for 10 minutes. After electrical stimulation, straight leg raising tests again to confirm the range of motion of the hip joint flexion. Results: As a result of this study, it was confirmed that the joint range of motion was significantly improved for both active and passive straight leg raising tests after application of motor nerve electrical stimulation(p<.05). Conclusions: With a strong electrical stimulation treatment of 1 Hz, the effect similar to the contraction and relaxation technique used in manual therapy was confirmed through the joint range of motion. In the future, motor nerve electrical stimulation therapy can be used for musculoskeletal physical therapy to provide a new approach for patients with reduced pain and joint range of motion due to muscle tension.

• Journal of IKEEE
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• v.14 no.2
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• pp.9-15
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• 2010

In this study, we have been proposed the new type of a transcranial magnetic stimulation adopted a variable voltage capacitor with Cockcroft-Walton circuit and constant-frequency current resonant half-bridge inverter. This a transcranial magnetic stimulation has some merits compared with the conventional one. First, it doesn't require the high voltage transformer. And second, it has less switching losses, compact size and capability in adjusting the transcranial magnetic stimulation output energy precisely. In this paper, we have performed the output characteristics of a transcranial magnetic stimulation system which is well known as magnetic stimulation. The tested results are described as a function of pulse repetition rate and switching numbers of the half-bridge inverter.

• Journal of the Korean Applied Science and Technology
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• v.21 no.2
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• pp.182-189
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• 2004

On contraction of the muscles, marked changes in X-ray reflections are observed, suggesting that conformational changes of contractile molecules and the movement of myosin heads during muscle contraction. Time slice requires tension peak after the onset of stimulation and the height of tension peak depends on the number of twitch cycle. The muscles were stimulated by five successive stimuli at an interval of 80 ms started while the tension was still being exerted by the muscles. The intensity of $I_{11}$, $I_{10}$, $143{\AA}$ and $215{\AA}$ reflection measured with 5ms time resolution and is recorded in isometric tension. The peak height of $I_{11}$ and $143{\AA}$ intensity is changed after the onset of a stimulation $I_i$, and the length of twitch is shortened by successive twitches in the case of stimulation $T_i$. On the other hand, the peak height of In and $215{\AA}$ intensity starts to decrease at the 1st twitch and remains constant at low peak height without appreciable recovery during the contraction term. In the case of successive twitch stimulation, the myosin heads of muscle are once moved from their resting position and never returned to their initial position.

• The Korean Journal of Pain
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• v.18 no.1
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• pp.10-14
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• 2005

Background: Previous studies have suggested synergistic analgesic drug interactions between NSAIDs and opioids in neuropathic and inflammatory pain models. The aim of this study was to investigate the analgesic drug interaction between intraperitoneal (IP) ketorolac and morphine in radiant thermal stimulation rat. Methods: Initially, we assessed the withdrawal latency time of the hindpaw to radiant thermal stimulation every 15 min for 1 hour and every 30 min for next 1 hour after IP normal saline 5 ml (control group). The latency time was changed into percent maximal possible effect (%MPE). Next, IP dose response curves were established for the %MPE of morphine (0.3, 1, 3, 10 mg/kg) and ketorolac (3, 10, 30 mg/kg) to obtain the $ED_{50}$ for each agent. And we confirmed that the IP morphine effect was induced by opioid receptor through IP morphine followed by IP naloxone. At last, we injected three doses of IP ketorolac (3, 10, 30 mg/kg) mixed with one dose of morphine (2 mg/kg) for fixed dose analysis. Results: IP morphine delayed the paw withdrawal latency time dose dependently, but not ketorolac. $ED_{50}$ of IP morphine was 2.1 mg/kg. And the IP morphine effect was reversed to control level by IP naloxone. IP ketorolac + morphine combination showed no further additional effects on paw withdrawal latency time over morphine only group. Conclusions: IP ketorolac did not produce antinociceptive effect during radiant thermal stimulation. There was neither additional nor synergistic analgesic interaction between IP morphine and ketorolac in thermal stimulation rat.

• Journal of Biomedical Engineering Research
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• v.23 no.4
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• pp.287-293
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• 2002

For non-contact nerve stimulations using time varying magnetic field, high amplitude current pulses have to be applied to a magnetic nerve stimulation coil. To increase the magnetic stimulation frequency we have to increase both power supply capacity and cooling capacity of the magnetic nerve stimulator. To alleviate these problems. we propose a new magnetic nerve stimulation coil design methods. Utilizing magnetic mirror effect of a ferro-magnetic plate attached to a magnetic stimulation coil. we have improved efficiency of the stimulation coil. We have analyzed magnetic mirror effect for various kinds of stimulation coils using the finite element method, and we present experimental results obtained with several kinds of stimulation coils.

• Journal of Magnetics
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• v.16 no.1
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• pp.51-57
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• 2011

A power supply for magnetic-stimulation devices was designed via a control algorithm that involved a start current application based on a resonant converter. In this study, a new power supply for magnetic-stimulation devices was designed by controlling the pulse repetition frequency and pulse width. The power density could be controlled using the start-current-compensation and ZCS (zero-current switching) resonant converter. The results revealed a high-repetition-frequency, high-power magnetic-stimulation device. It was found that the stimulation coil current pulse width and that pulse repetition frequency could be controlled within the range of 200-450 ${\mu}S$ and 200-900 pps, respectively. The magnetic-stimulation device in this study consisted of a stimulation coil device and a power supply system. The maximum power of the stimulation coil from one discharge was 130 W, which was increased to 260 W using an additional reciprocating discharge. The output voltage was kept stable in a sinusoidal waveform regardless of the load fluctuations by forming voltage and current control using a deadbeat controller without increasing the current rating at the starting time. This paper describes this magnetic-stimulation device to which the start current was applied.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.827-831
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• 2005

Acupuncture and Low-frequency-wave stimulation at the Points (LI4, LI6, LI8 and LI11) on the large intestine meridian of hand resulted in same pattern about body temperature profiles with time. Upon 4Hz and 50Hz stimulation the temperature profiles on LI6 and LI11 were declined probably because of their relationship with Proprioceptive activity. Temperature different at the points was higher when the intensity of low-frequency-wave stimulation was stronger.

• Proceedings of the KIEE Conference
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• 1999.07b
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• pp.656-658
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• 1999

This paper presents musculotendon model to show the decline in muscle force during functional electrical stimulation (FES). It represent muscle activation and contraction concepts including muscle fatigue. A muscle fatigue term in activation dynamics as a function of the intracellular acidification and the pulsewidth of stimulation pulses change activation to decline muscle force. The computer simulation shows that muscle force decline in stimulation time.

• Science of Emotion and Sensibility
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• v.6 no.4
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• pp.15-23
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• 2003

Recently, there have been many attempts to develop BCI (brain computer interface) based on EEG (electroencephalogram). Measurement and analysis of EEG evoked by particular stimulation is important for the design of brain wave pattern and interface of BCI. The purpose of this study is to develop a general-purpose system that measures subject's reaction time after audio-visual stimulation which can work together with any other biosignal measurement systems. The entire system is divided into four modules, which are stimulation signal generation, reaction time measurement, evoked potential measurement and synchronization. Stimulation signal generation module was implemented by means of Flash. Measurement of the reaction time (the period between the answer request and the subject reaction) was achieved by self-made microcontroller system. EEG measurement was performed using the ready-made hardware and software without any modification. Synchronization of all modules was achieved by, first, the black-and-white signals on the stimulation screen synchronized with the problem presentation and the answer request, second, the photodetectors sensing the signals. The proposed method offers easy design of purpose-specific system only by adding simple modules (reaction time measurement, synchronization) to the ready-made stimulation and EEG system, and therefore, it is expected to accelerate the researches requiring the measurement of evoked response and reaction time.