• Title/Summary/Keyword: Threshold stimulus

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Modification in the Responsiveness of Dorsal Horn Cells during Allyl Isothiocyanate-Induced Inflammation in the Cat (Allyl Isothiocyanate 유발 피부염에 의한 척수후각세포의 활동성 변동)

  • Yun, Young-Bok;Kim, Jin-Hyuk;Shin, Hong-Kee;Kim, Kee-Soon
    • The Korean Journal of Physiology
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    • v.24 no.2
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    • pp.305-317
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    • 1990
  • The present study was performed to investigate modification in the electrophysiological characteristics of cat dorsal horn cells during neurogenic inflammation induced by mustard oil. The results obtained were summarized as follows: 1) Following subcutaneous injection of mustard oil the majority of wide dynamic range (WDR) cells (10/15 units) showed enhanced responses (80%) to brush, while the responses to all types of mechanical stiumli were enhanced in 3/15 units. One cell was further activated by pinch and the another was not affected at all after induction of inflammation. 2) The sensitization of WDR cell was resulted from subcutaneous injection of mustard oil either inside or outside of the receptive field (RF), whereas the spontaneous activity increased only after mustard oil was injected inside of the RF. 3) In the animal with inflammation the responses of high threshold (HT) cell to noxious stimulus were not altered, while HT cell responded to such mechanical stimulus as pressure which was usually ineffective in normal animals. 4) After induction of inflammation, low threshold (LT) cell appeared to be converted to WDR cell, showing responses not only to brush but also to pressure and pinch. 5) The mustard oil-induced inflammation enhanced responses of WDR and HT cells to the thermal stimuli and also resulted in a pronounced after-discharge in WDR cells. 6) After subcutaneous injection of lidocaine, the increased background activity of WDR cells due to inflammation was almost completely abolished. 7) A subcutaneous injection of mustard oil inside of the RF invariably desensitized the dorsal horn cells which receive sensory inputs from the inflamed RF. From the results of Present study it was revealed that a neurogenic inflammation induced by mustard oil resulted in an enhancement of responses of cat dorsal horn cells to mechanical and thermal stimuli.

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A Perceptual Rate Control Algorithm with S-JND Model for HEVC Encoder (S-JND 모델을 사용한 주관적인 율 제어 알고리즘 기반의 HEVC 부호화 방법)

  • Kim, JaeRyun;Ahn, Yong-Jo;Lim, Woong;Sim, Donggyu
    • Journal of Broadcast Engineering
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    • v.21 no.6
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    • pp.929-943
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    • 2016
  • This paper proposes the rate control algorithm based on the S-JND (Saliency-Just Noticeable Difference) model for considering perceptual visual quality. The proposed rate control algorithm employs the S-JND model to simultaneously reflect human visual sensitivity and human visual attention for considering characteristics of human visual system. During allocating bits for CTU (Coding Tree Unit) level in a rate control, the bit allocation model calculates the S-JND threshold of each CTU in a picture. The threshold of each CTU is used for adaptively allocating a proper number of bits; thus, the proposed bit allocation model can improve perceptual visual quality. For performance evaluation of the proposed algorithm, the proposed algorithm was implemented on HM 16.9 and tested for sequences in Class B and Class C under the CTC (Common Test Condition) RA (Random Access), Low-delay B and Low-delay P case. Experimental results show that the proposed method reduces the bit-rate of 2.3%, and improves BD-PSNR of 0.07dB and bit-rate accuracy of 0.06% on average. We achieved MOS improvement of 0.03 with the proposed method, compared with the conventional method based on DSCQS (Double Stimulus Continuous Quality Scale).

The Preliminary Study for Normative Current Perception Threshold values in the Korean Adults (성인의 Current Perception Threshold 예비조사)

  • Park, Dae-Gyu;Chun, Sung-Hong;Jeon, Jae-Soo;Kim, Yong-Ik;Hwang, Kyung-Ho;Park, Wook
    • The Korean Journal of Pain
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    • v.10 no.1
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    • pp.5-10
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    • 1997
  • Background : The Current Perception Threshold (CPT) provides an objective, quantitative gauge of sensory nerve integrity which is obtainable from any cutaneous site. CPT measurement can confirm and quantify or rule out dysfunction of nerve through comparison with established normative values ($Neuval^{TM}$ CPT database). The aim of this study is to compare collected data from Korean adults with $Neuval^{TM}$ CPT database. Method : Normative data from 5 standard test site in face, hand, toe were obtained from 50 healthy adults. Three frequencies(5, 250, 2000 Hz) were stimulated with $Neuromoter^{(R)}$ CPT device. Results : The results of our data were statistically significantly different than Neuval data except in face, but within normal range. Sensory Threshold increased as the frequency of the stimulus changed from 5 Hz to 250 Hz to 2000 Hz., and from face to hand to toe. Conclusion : CPT testing is a valuable neurologic testing modality that is noninvasive and highly reliable for diagnosis and evaluation of sensory nerves where neuropathy is suspected.

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Fabrication and Evaluation of Tactile Stimulator Array Using Stacked PZT

  • Yoon, Myoung-Jong;Kwon, Tae-Kyu;Yu, Kee-Ho;Kim, Nam-Gyun
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.171-175
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    • 2004
  • A tactile stimulator array using stacked PZT is fabricated and evaluated in this paper. The purpose of this research is the development of a tactile stimulator to represent the obstacle information for the visually disabled. As a first step of this research, we investigate the physiological characteristics of tactile stimuli and design a tactile stimulator based on the investigated results. Also we evaluated a fabricated tactile stimulator. The prototype of tactile stimulator which has 2x2 tactor elements with 3mm spacing is fabricated using stacked PZT actuator. In order to evaluate the characteristics of this tactile stimulator, physiological experiments are carried out. In the experiment, the threshold of tactile stimulus intensity within a frequency range of 5-500Hz and at various stimulus amplitudes are investigated. According to the obtained experimental result, the input signal of tactile stimulator for the transfer of obstacle information is determined. Also physiological experiments of multi-stimuli recognition such as shift and rotation are carried out.

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Study on Electric Stimulus Pattern in Cochlear Implant Using a Computer Model (신경모델링을 이용한 인공와우 전기자극 패턴 연구)

  • Yang, Hyejin;Woo, Jihwan
    • Journal of the Institute of Electronics and Information Engineers
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    • v.49 no.12
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    • pp.249-255
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    • 2012
  • A cochlear implant system uses charge-balanced biphasic pulses that are known to reduce tissue damage than monophasic pulses. In this study, we investigated effect of pulse pattern on neural responses using a computer model, based on the Hodgkin-Huxley equation. Electric pulse phase, pulse duration, and phase gap have been systematically varied to characterize auditory nerve responses. The results show that neural responses, dynamic range and threshold are represented as a function of stimulus patterns and duration. The results could greatly extend to develop more efficient cochlear implant stimulation.

The Effects of Interferential Current therapy on Spasticity, Range of Motion, and Balance Ability in stroke Patient (뇌졸중 환자의 경직 및 관절가동범위, 균형에 간섭전류 치료가 미치는 효과)

  • Kim, Bo-Yong;Choi, Won-Ho
    • The Journal of Korean Physical Therapy
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    • v.25 no.4
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    • pp.187-194
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    • 2013
  • Purpose: The aim of this study was to investigate the effects of interferential current therapy (ICT) on spasticity, ROM, and the balance function in patients with stroke. Methods: 30 inpatients with stroke were randomly divided into 2 groups: the ICT group (n=15) and the placebo-ICT group (n=15). Two groups have got the traditional rehabilitation for 30 minutes before applying either ICT or placebo-ICT stimulation. The stimulus of ICT has been applied to gastrocnemius at the level of 100 Hz, two times of sensation threshold, while the placebo-ICT group has put on the electrode without electrical stimulus. To assess spasticity in ankle, the modified Ashworth scale (MAS) was used, and goniometer was applied to measure the passive range of motion (PROM). Also, the Berg Balance Scale (BBS), the Timed-up and go (TUG), and the Functional Reach Test (FRT) were carried out to examine the balance ability. Results: The ICT group showed a significant reduction of spasticity and significantly increased PROM than the placebo-ICT group (p<0.05). The placebo-ICT group did not show significant changes in the BBS, the TUG, and the FRT, while the ICT group significantly improved the BBS, the TUG, and the FRT (p<0.05). Conclusion: Our results demonstrated that ICT applied to gastrocnemius effectively decreased spasticity and improved range of motion and balance function in patients with stroke.

MEASUREMENT OF THE EXCESSIVE STIMULUS TIME AFTER THE SENSORY THRESHOLD LEVEL DURING ELECTRIC PULP TESTING (전기 치수 검사 시 역치 자극 이후 과용(過用) 자극 시간의 측정)

  • Nam, Ki-Chang;Ahn, Seon-Hui;Kim, Soo-Chan;Kim, Deok-Won;Lee, Seung-Jong
    • Restorative Dentistry and Endodontics
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    • v.29 no.3
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    • pp.226-232
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    • 2004
  • Use of electric pulp testing elicits painful response in vital teeth. In this study, we examined the excessive time from pain feeling to stimulation disconnection in clinical situation. D626D (Parkell Inc., USA.) scan type electric pulp tester was used in total of 23 young healthy individuals. Each of the right central incisors and first premolars were used as testing teeth. Stimulation disconnection was achieved by EMG in anterior belly of digastric muscle, finger span, and voice and the excessive stimulation time over the sensory thresh-old was recorded. As a result, we found that the short responses before the stimulation disconnection appeared following order:EMG, finger span, and voice. The EMG disconnection is suggested to be used to reduce the excessive stimulus time in electric pulp testing.

Conceptualizing 5G's of Green Marketing for Retail Consumers and Validating the Measurement Model Through a Pilot Study

  • ANSARI, Hafiz Waqas Ahmed;FAUZI, Waida Irani Mohd;SALIMON, Maruf Gbadebo
    • Journal of Distribution Science
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    • v.20 no.4
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    • pp.33-50
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    • 2022
  • Purpose: This pilot study aims to conceptualize a new green marketing mix for retail consumers based on Stimulus-Organism-Response (SOR) model. Moreover, it also aims to conceptualize a testable research model of new green marketing mix with consumers' green purchasing behavior, and to validate the measurement model with traditional as well as modern suggested validating techniques. Research design, data and methodology: A pilot test data from 75 respondents of retail buyers of energy-efficient electric appliances in Pakistan were tested for the confirmatory factor analysis (CFA) by examining a measurement model of the construct through different validation techniques (like Composite Reliability, McDonald's Omega (ω), rho (ρA), HTMT, etc.) as heretofore these scales were not validated through these modern methods. Results: The results revealed that the instrument has a certain degree of reliability and validity through different validating techniques. All the measurement items reach the suggested threshold values. Conclusions: Therefore, this study conceptualized an integrated framework of all the three stakeholders of the environment (government, companies, and public or consumers) to achieve environmental sustainability. Hence, future studies can extend these findings and conduct a full-scale study to establish an empirical relationship between the 5G's of green marketing for retailing businesses and consumers' green purchase behavior.

Association of Sexual Disorders with Peripheral Neuropathy in Alcohol Dependence (주정의존에서 성기능장애와 말초신경염의 연관성)

  • Cheon, Jin-Sook;Han, Ho-Sung;Kim, Kee-Chan;Jung, Ho-Joong
    • Korean Journal of Biological Psychiatry
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    • v.4 no.1
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    • pp.108-115
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    • 1997
  • The alcoholic neuropathies developed in approximately 34% of chronic alcoholics and the sexual dysfunction had been experienced in 8-54% of male alcoholics(Schiavi 1990). The aims of this study were to identify the prevalence of subclinical polyneuropathies and sexual disorders in alcohol dependence, and to evaluate the association between them. The nerve conduction velocity(NCV), electromyography(EMG), and pudendal somatosensory evoked potentials(SEPs) were tested for the male alcoholics(N=34) and controls(N=17 for NCV & EMG, N=25 for pudendal SEPs). The pudendal SEPs were measured by the following procedures, in which we stimulated the dorsal nerve of penis attached by the ring electrode(stimulus intensity, three times of threshold : stimulus rate, 1-4.7Hz : stimulus duration, 0.1 or 0.2msec), and recorded at the scalp(active electrode, 2cm behind Cz : reference electrode, Fz). The NCV and EMG detected signs of peripheral neuropathies in 79.4% of alcoholics. Among the alcoholics, 64.7% were abnormal on the pudendal SEPs. Among the alcoholics who revealed abnormality on EMG and NCV, 81.4% were abnormal on the pudendal SEPs, in which 51.9% were not responded. The P1 latencies of pudendal SEPs on neuropathic alcoholics were significantly delayed(p<0.05) than non-neuropathic alcoholics. There was a relative correlation between peripheral neuropathies and sexual disorders in the alcoholics. The prevalence of subclinical neuropathies and sexual disorders seemed to be much higher in alcohol dependence than expectation, and these two problems were relatively correlated, and our results suggested that the peripheral polyneuropathies were one of the prerequisites of sexual disorders.

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Comparison of Stereoscopic Fusional Area between People with Good and Poor Stereo Acuity (입체 시력이 양호한 사람과 불량인 사람간의 입체시 융합 가능 영역 비교)

  • Kang, Hyungoo;Hong, Hyungki
    • Journal of Korean Ophthalmic Optics Society
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    • v.21 no.1
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    • pp.61-68
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    • 2016
  • Purpose: This study investigated differences in stereoscopic fusional area between those with good and poor stereo acuity in viewing stereoscopic displays. Methods: Stereo acuity of 39 participants (18 males and 21 females, $23.6{\pm}3.15years$) was measured with the random dot stereo butterfly method. Participants with stereo-blindness were not included. Stereoscopic fusional area was measured using stereoscopic stimulus by varying the amount of horizontal disparity in a stereoscopic 3D TV. Participants were divided into two groups of good and poor stereo acuity. Criterion for good stereo acuity was determined as less than 60 arc seconds. Measurements arising from the participants were statistically analyzed. Results: 26 participants were measured to have good stereo acuity and 13 participants poor stereo acuity. In case of the stereoscopic stimulus farther than the fixation point, threshold of horizontal disparity for those with poor stereo acuity were measured to be smaller than the threshold for those with good stereo acuity, with a statistically significant difference. On the other hand, there was no statistically significant difference between the two groups, in case of the stereoscopic stimulus nearer to the fixation point. Conclusions: In viewing stereoscopic displays, the boundary of stereoscopic fusional area for the poor stereo acuity group was smaller than the boundary of good stereo acuity group only for the range behind the display. Hence, in viewing stereoscopic displays, participants with poor stereo acuity would have more difficulty perceiving the fused image at farther distances compared to participants with good stereo acuity.