1.Measuring Gastrointestinal Electrical Activity With Extracellular Electrodes: Author's Reply.
Kenton M SANDERS ; Grant HENNIG
Journal of Neurogastroenterology and Motility 2015;21(4):625-626
No abstract available.
Electrodes*
2.Measuring Gastrointestinal Electrical Activity With Extracellular Electrodes.
Gregory O'GRADY ; Timothy R ANGELI ; Peng DU ; Leo K CHENG
Journal of Neurogastroenterology and Motility 2015;21(4):623-624
No abstract available.
Electrodes*
3.Photopic ON- and OFF- Responses in Korean Normal Subjects.
Su Eun PARK ; Jee Ho CHANG ; Kyung Seek CHOI ; Jung Hee LEE ; Young Hoon OHN
Journal of the Korean Ophthalmological Society 2008;49(3):471-478
PURPOSE: To explore the effects of stimulus duration, stimulus intensity, and background luminance on the amplitude and waveform of the ON- and OFF- responses of photopic ERG and to provide standard parameters of ON- and OFF- responses for normal Korean populations. METHODS: Twenty normal subjects (20 eyes) were enrolled to record photopic ON-and OFF-responses using a contact lens electrode with built-in LEDs and an LED-driver. The influence of stimulus duration on wave amplitudes was studied at flash durations that varied from 5 to 200 ms. The influence of stimulus intensity was studied with 0.4, 0.7, 1.1, 1.4, 1.7, 1.9, 2.0, and 2.1 log cd/m2. In addition, the influence of background luminance was studied with 20, 30, 40, and 50 cd/m2. RESULTS: Among 20 normal subjects, the d-waves in 16 subjects were isolated from b-waves with more than 50 ms of stimulus duration. The d-wave was observed for a 30-ms stimulus duration in 3 subjects and for a 100-ms duration in 1 subject. The amplitudes of the b-and d-waves increased as stimulus intensity was increased. The amplitudes of b-and d-waves decreased as background luminance was increased. CONCLUSIONS: Our results suggest that the clinical use of ON-and OFF-response recording can be obtained with stimulus parameters from 100 to 150 ms in duration and a 1.7-2.1 log cd/m2 intensity under 30-40 cd/m2 background luminance.
Electrodes
;
Electroretinography
4.Study on the Evaluation of TRS-398 Quality Factors with Central Electrode Corrections for Small Cylindrical Chambers.
Yeong Rok KANG ; Chang Yeol LEE ; Jin Ho KIM ; Young Min MOON ; Dong Won KWAK ; Sang Koo KANG ; Jeung Kee KIM ; Kwangmo YANG ; Dong Hyeok JEONG
Korean Journal of Medical Physics 2011;22(3):148-154
The quality factors (kQ,Q0) were evaluated by appling the results recently studied for the effect of central electrode in TRS-398 protocol. The PTW-31010 and IBA-CC13 chambers were used in this study. The quality factors were calculated as a function of beam quality for high energy electron and photon beams and compared with data currently used in TRS-398 protocol. In the PTW-31010 chamber using aluminium electrode, appling the new central electrode collections, the quality factors were 0.4% and 0.9% higher than current TRS-398 data for high energy photon and electron beams respectively. In the IBA-CC13 chamber using C-552 electrode, there are no variations in quality factors compared to TRS-398 data currently used.
Electrodes
;
Electrons
5.Study for Multi Channel Radiation Detector Using of Microfilm and Carbon Electrode.
Kyo Chul SHIN ; Hyong Geun YUN ; Dong Hyeok JEONG ; Yong Kee OH ; Jhin Kee KIM ; Ki Hwan KIM ; Jeung Kee KIM
Korean Journal of Medical Physics 2005;16(3):111-115
We have designed the multi channel detector for the quality assurance of clinical photon beams. The detector was composed of solid phantom inserted by six plane-parallel ionization chambers at different depth. The chamber as a mini plane parallel chamber was made of carbon coated microfilms. In this study the electrical characteristics of the six chambers in the solid phantom were evaluated using 6 MV photon beam. The leakage currents were less than 0.5 pA, reproducibility was less than 0.5%, linearity was less than 0.5%, and dose rate effect was less than 0.7%. In addition the effect of dose variation from other chambers was estimated to maximum 0.8% approximately. The developed detector can be used for quality determination in output dosimetry or measurement of percentage depth dose approximately for clinical photon beam.
Carbon*
;
Electrodes*
6.Comparison of Electroretinogram Waveforms Acquired Using Monopolar ERG-Jet Electrode and Bipolar Burian-Allen Electrode.
Jihyun PARK ; Hokyung LEE ; Sung Joon PARK ; Yoon Hwa KIM
Journal of the Korean Ophthalmological Society 2010;51(9):1217-1223
PURPOSE: To compare electroretinogram (ERG) waveforms acquired using an ERG-jet electrode and a Burian-Allen electrode. METHODS: ERGs were recorded with an ERG-jet electrode and a Burian-Allen electrode from both eyes of 29 volunteers. Three consecutive recordings were obtained with both electrodes from the left eye of another 6 volunteers. Peak-to-trough amplitudes and peak implicit times were compared between both eyes, and between the 2 types of electrodes. Interpersonal and intrapersonal variation were also compared. RESULTS: The differences in amplitude and implicit time between the right and left eyes were not influenced by the type of electrode. The amplitude of the ERG acquired using the Burian-Allen electrode, however, showed significant differences between both eyes, contrary to the amplitude acquired using the ERG-jet electrode. ERG recordings obtained using the ERG-jet electrode generally showed higher amplitude, shorter implicit time, and less interpersonal and intrapersonal variation than ERG recordings obtained using the Burian-Allen electrode. CONCLUSIONS: In this application, the ERG-jet ERG electrode appeared to be superior to the Burian-Allen electrode in terms of both usefulness and consistency.
Electrodes
;
Eye
7.Hematoma-Related Nonhabitual Seizures during Subdural Electrode Monitoring.
Kyoung Jin HWANG ; Eun Yeon JOO ; Seung Bong HONG ; Dae Won SEO
Journal of Clinical Neurology 2018;14(3):415-416
No abstract available.
Electrodes*
;
Seizures*
8.Serum ionized Ca measured with new ion-selected electrode and Q-oTc interval in newborn infants.
Beom Joo KIM ; Chang Hee HAN ; Heng Mi KIM ; Doo Hong AHN
Journal of the Korean Pediatric Society 1991;34(3):303-310
No abstract available.
Electrodes*
;
Humans
;
Infant, Newborn*
9.Full-Field and Focal Macular Electroretinography in Normal Subjects using MacADIOS 411 and Maculoscope.
Seung Jun BAE ; Hokyung LEE ; Jin Hyung YOO
Journal of the Korean Ophthalmological Society 1996;37(5):765-775
Specific values for amplitude and implicit time may differ among laboratory due to normal variations in recording electrodes, equipment, and protocol. We presented the results of fulHield and focal macular electroretinography in normal subjects using MacADIOS 411 and Maculoscope. Full-field electroretinograms were obtained in 87 normal subjects (65 males, 22 females) and focal macular electroretinograms were recorded in 33 valunteers(18 males, 15 females) under controlled condition. Age-matched norms were given in table, and for the purpose of clinical application, range of values was given for each group.
Electrodes
;
Electroretinography*
;
Humans
;
Male
10.An Experimental Study on Hepatic Ablation Using an Expandable Radio-Frequency Needle Electrode.
Dongil CHOI ; Hyo Keun LIM ; Jong Min PARK ; Bo Kyung KANG ; Ji Young WOO ; Hyun Jung JANG ; Seung Hoon KIM ; Won Jae LEE ; Cheol Keun PARK ; Jin Seok HEO
Journal of the Korean Radiological Society 1999;41(6):1127-1132
PURPOSE: The purpose of this study was to determine the factors influencing on the size of thermal lesions after ablation using an expandable radio-frequency needle electrode in porcine liver. MATERIALS AND METHODS: Ablation procedures involved the use of a monopolar radio-frequency generator and 15-G needle electrodes with four and seven retractable hooks (RITA Medical System, Mountain View, Cal.,U.S.A.). The ablation protocol in fresh porcine liver comprised of combinations of varying hook deployment, highest set temperature, and ablation time. Following ablation, the maximum diameter of all thermal lesions was measured on a longitudinal section of the specimen. Ten representive lesions were examined by an experienced pathologist. RESULTS: At 3-cm hook deployment of the needle electrode with four lateral hooks, the size of spherical thermal lesions increased substantially with increases in the highest set temperature and ablation time until 11 minutes. After 11 minutes lesion size remained similar, with a maximum diameter of 3.3 cm. At 2-cm hook deployment, sizes decreased to about 2/3 of those at 3 cm, and at 1-cm hook deployment lesions were oblong. At 3-cm hook deployment of a needle electrode with seven hooks, the size of thermal lesions increased with increasing ablation time until 14 minutes, and the maximum diameter was 4.1 cm. Microscopic examination showed a wide zone of degeneration and focal coagulation necrosis. CONCLUSION: The size of thermal lesions produced by the use of an expandable radio-frequency needle electrode were predictable, varying according to degree of hook deployment, highest set temperature, and ablation time.
Electrodes*
;
Liver
;
Necrosis
;
Needles*