• The Korean Journal of Physiology
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• 제30권1호
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• pp.117-124
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• 1996

This study evaluated the hypothesis that motoneuron collaterals modulate the excitability of ventral spinocerebellar tract neurons. In acute cats, 128 ventral cerebellar tract cells were studied extracellularly to determine the effects of ventral root stimuli. The majority of the cells responded to ventral root stimulation with either short or long latency increases in spike discharge. In many cells with sufficient spontaneous activity ventral root stimulation also evoked a long lasting reduction in activity. In preparations with the dorsal root ganglion removed VSCT neurons had similar response properties. In some cells contralateral ventral root stimulation also evoked excitatory responses. These findings indicate the VSCT can provide the cerebellum with information regarding activity in the final output neurons of the motor system, the alpha motoneurons.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2019년도 춘계종합학술대회
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• pp.465-466
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• 2019

특별한 차별성 없이 평준화되고 있는 제품들로 넘쳐나는 과대경쟁 마케팅 환경 속에 브랜드 및 제품의 스토리텔링 마케팅은 고객 지향적 브랜드 커뮤니케이션 활동으로 주목받고 있다. 효과적이고 지속적인 경쟁유지를 위한 USP전략을 성공적으로 활용한 사례를 중심으로 스토리텔링 구성요소인 실행성, 이야기성 및 상호작용성의 관점에서 분석하여 고객과의 상호작용을 긍정적으로 이끌어 내고 지속적인 경쟁우위를 유지하기 위한 방법을 알아보았다.

• 반도체디스플레이기술학회지
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• 제20권2호
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• pp.1-5
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• 2021

Ultraviolet (UVA)-emissive BaSiO₃:Ce³⁺ phosphor was astonishingly reproducible by vacuum-sintering at a high temperature through a simple solid-state reaction method. It was conveniently formed in BaSiO₃ phases. The compound showed the UVA emission and the UV-VUV excitation due to 5d-4f transitions from Ce³⁺ ions: emission peak at 380 nm with a 56 nm width. Its temperature dependence and vacuum UV excitability were examined for practical application as an excimer discharge lamp, which showed the high thermal stability (80% at 100℃) and the strong VUV excitations at 145 nm and 172 nm.

• The Korean Journal of Physiology and Pharmacology
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• 제1권6호
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• pp.625-637
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• 1997

Calcium ions are implicated in a variety of physiological functions, including enzyme activity, membrane excitability, neurotransmitter release, and synaptic transmission, etc. Calcium antagonists have been known to be effective for the treatment of exertional angina and essential hypertension. Selective and nonselective voltage-dependent calcium channel blockers also have inhibitory action on the acute and tonic pain behaviors resulting from thermal stimulation, subcutaneous formalin injection and nerve injury. This study was undertaken to investigate the effects of iontophoretically applied $Ca^{++}$ and its antagonists on the responses of WDR (wide dynamic range) cells to sensory inputs. The responses of WDR cells to graded electrical stimulation of the afferent nerve and also to thermal stimulation of the receptive field were recorded before and after iontophoretical application of $Ca^{++}$, EGTA, $Mn^{++}$, verapamil, ${\omega}-conotoxin$ GVIA, ${\omega}-conotoxin$ MVIIC and ${\omega}-agatoxin$ IVA. Also studied were the effects of a few calcium antagonists on the C-fiber responses of WDR cells sensitized by subcutaneous injection of mustard oil (10%). Calcium ions and calcium channel antagonists ($Mn^{++}$, verapamil, ${\omega}-conotoxin$ GVIA & ${\omega}-agatoxin$ IVA) current-dependently suppressed the C-fiber responses of WDR cells without any significant effects on the A-fiber responses. But ${\omega}-conotoxin$ MVIIC did not have any inhibitory actions on the responses of WDR cell to A-fiber, C-fiber and thermal stimulation. Iontophoretically applied EGTA augmented the WDR cell responses to C-fiber and thermal stimulations while spinal application of EGTA for about $20{\sim}30\;min$ strongly inhibited the C-fiber responses. The augmenting and the inhibitory actions of EGTA were blocked by calcium ions. The WDR cell responses to thermal stimulation of the receptive field were reduced by iontophoretical application of $Ca^{++}$, verapamil, ${\omega}-agatoxin$ IVA, and ${\omega}-conotoxin$ GVIA but not by ${\omega}-conotoxin$ MVIIC. The responses of WDR cells to C-fiber stimulation were augmented after subcutaneous injection of mustard oil (10%, 0.15 ml) into the receptive field and these sensitized C-fiber responses were strongly suppressed by iontophoretically applied $Ca^{++}$, verapamil, ${\omega}-conotoxin$ GVIA and ${\omega}-agatoxin$ IVA. These experimental findings suggest that in the rat spinal cord, L-, N-, and P-type, but not Q-type, voltage-sensitive calcium channels are implicated in the calcium antagonist-induced inhibition of the normal and the sensitized responses of WDR cells to C-fiber and thermal stimulation, and that the suppressive effect of calcium and augmenting action of EGTA on WDR cell responses are due to changes in excitability of the cell.

• 대한소아치과학회지
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• 제27권1호
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• pp.7-14
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• 2000

가바성 억제 신경세포는 해마의 정상적인 기능을 조절하는데 중요한 역할을 하며 해마 병변을 유발하는 중요한 요소이다. 본 연구는 in vivo 실험법을 사용하여 해마 CA1 영역에서의 전기 생리학적 반응을 측정함으로써 가바성 신경세포의 기능을 분석하고 이를 슬라이스 실험법과 비교하고자 하였다. Fimbria-fonix 전기자극시 전형적인 population spike가 나타났고 $10{\sim}M$ bicuculline 존재하에서는 전기자극에 의해 burst 형태의 population spike가 나타났다. Population spike의 크기는 자극 강도에 비례하였으며 그 숫자도 bicuculline 전극사용시와 같이 동일한 양상을 보였다. CA1 영역의 흥분성 수준을 측정하기 위해 paired-pulse 자극을 하였는데 짧은 자극 간격에서 억제성 반응을 보였고 burst형태의 afterdischarge를 나타내었다. CA1 영역에서 in vivo실험법을 사용한 가바성 신경세포반응의 결과는 추체세포의 흥분성 조절을 효과적으로 분석할 수 있으며 in vitro 실험법에 비해 기능적 평가가 더욱 이상적임을 알 수 있다.

• Molecules and Cells
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• 제20권3호
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• pp.315-324
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• 2005

Pain is an unpleasant sensation experienced when tissues are damaged. Thus, pain sensation in some way protects body from imminent threat or injury. Peripheral sensory nerves innervated to peripheral tissues initially respond to multiple forms of noxious or strong stimuli, such as heat, mechanical and chemical stimuli. In response to these stimuli, electrical signals for conducting the nociceptive neural signals through axons are generated. These action potentials are then conveyed to specific areas in the spinal cord and in the brain. Sensory afferent fibers are heterogeneous in many aspects. For example, sensory nerves are classified as $A{\alpha}$, $-{\beta}$, $-{\delta}$ and C-fibers according to their diameter and degree of myelination. It is widely accepted that small sensory fibers tend to respond to vigorous or noxious stimuli and related to nociception. Thus these fibers are specifically called nociceptors. Most of nociceptors respond to noxious mechanical stimuli and heat. In addition, these sensory fibers also respond to chemical stimuli [Davis et al. (1993)] such as capsaicin. Thus, nociceptors are considered polymodal. Recent advance in research on ion channels in sensory neurons reveals molecular mechanisms underlying how various types of stimuli can be transduced to neural signals transmitted to the brain for pain perception. In particular, electrophysiological studies on ion channels characterize biophysical properties of ion channels in sensory neurons. Furthermore, molecular biology leads to identification of genetic structures as well as molecular properties of ion channels in sensory neurons. These ion channels are expressed in axon terminals as well as in cell soma. When these channels are activated, inward currents or outward currents are generated, which will lead to depolarization or hyperpolarization of the membrane causing increased or decreased excitability of sensory neurons. In order to depolarize the membrane of nerve terminals, either inward currents should be generated or outward currents should be inhibited. So far, many cationic channels that are responsible for the excitation of sensory neurons are introduced recently. Activation of these channels in sensory neurons is evidently critical to the generation of nociceptive signals. The main channels responsible for inward membrane currents in nociceptors are voltage-activated sodium and calcium channels, while outward current is carried mainly by potassium ions. In addition, activation of non-selective cation channels is also responsible for the excitation of sensory neurons. Thus, excitability of neurons can be controlled by regulating expression or by modulating activity of these channels.

• Annals of Clinical Neurophysiology
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• 제13권1호
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• pp.1-12
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• 2011

Transcranial magnetic stimulation (TMS) is a non-invasive tool used to study aspects of human brain physiology, including motor function and the pathophysiology of various brain disorders. A brief electric current passed through a magnetic coil produces a high-intensity magnetic field, which can excite or inhibit the cerebral cortex. Although various brain regions can be evaluated by TMS, most studies have focused on the motor cortex where motor evoked potentials (MEPs) are produced. Single-pulse and paired-pulse TMS can be used to measure the excitability of the motor cortex via various parameters, while repetitive TMS induces cortical plasticity via long-term potentiation or long-term depression-like mechanisms. Therefore, TMS is useful in the evaluation of physiological mechanisms of various neurological diseases, including movement disorders and epilepsy. In addition, it has diagnostic utility in spinal cord diseases, amyotrophic lateral sclerosis and demyelinating diseases. The therapeutic effects of repetitive TMS on stroke, Parkinson disease and focal hand dystonia are limited since the duration and clinical benefits seem to be temporary. New TMS techniques, which may improve clinical utility, are being developed to enhance clinical utilities in various neurological diseases.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제15권1호
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• pp.7-10
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• 1993

The final purpose of oral & maxillofacial trauma is functional & esthetic repair. Nowadays, severe trauma involving with the head & neck trauma is increasing. After these trauma occurs, the patients develop similar signs & symptoms with the postoperative healing period, as like thurst, hypertention, excitability, disorientation, convulsion, et al. Because SIADH which is one of important complications after head trauma, shows similar clinical features after operation, we should pay attention to detect it. SIADH shows characteristic laboratory findings, as like hyponatremia, urine hyperosmolality, increased plasma ADH level, continued renal excretion of sodium, so we can easily distinguish it from postoperative conditions. This paper reports two cases, one was the case of the mandibular fracture and cerebral contusion, which included permanent SIADH. The other was the case of the multiple teeth injury and cerebral contusion, which was transient SIADH. We treated them with water restriction, hypertonic saline, and diuretics.

• 대한임상전기생리학회지
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• 제7권1호
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• pp.23-27
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• 2009

Purpose : The purpose of this study was to examine the effects of different medium frequency currents on afferent fibers. Methods : Thirty healthy volunteers who had no known history of neurological disorders were equally assigned to one of three groups; 2500Hz, 4000Hz, and control and each group was applied to the left wrist in palmer cutaneous branch of radial nerve by different medium frequency currents for 15 min. We measured the changes of thresholds for tactile, two-point discrimination, and thresholds for pain. Results : The results showed that the medium frequency currents stimulation increased thresholds for tactile, two-point discrimination, and thresholds for pain. However, there is no statistically significant difference between group 2500Hz and group 4000Hz. Conclusion : This may explain thresholds for tactile, two-point discrimination, and thresholds for pain plain medium frequency currents stimulation inhibits the excitability of afferent fibers, but the effect of the frequency difference within medium frequency currents is not demonstrated.

• 대한임상검사과학회지
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• 제40권2호
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• pp.142-146
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• 2008

Facial palsy is a general nerve disease which is occurred in a lateral incomplete or complete facial palsy. But it makes man restrict a social activity and so it is very important that we know the prognosis factors of a patient for medical care. We want to investigate the position and the patterns of the facial palsy according to sex and age. In this study, we performed the excitability test of the facial nerve on 103 patients (male 45 and female 58) which diagnosed as the Bell's palsy having an acute facial palsy, and the rate of the facial palsy was 42% (43 case) in right oculi and 58% (60 case) in left oculi. The facial palsy was appeared widely from young to elderly patients and especially, the rate of the facial palsy was high in age groups from 40 to 50.