• The Korean Journal of Physiology and Pharmacology
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• 제22권6호
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• pp.721-729
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• 2018

GABAergic control over dopamine (DA) neurons in the substantia nigra is crucial for determining firing rates and patterns. Although GABA activates both $GABA_A$ and $GABA_B$ receptors distributed throughout the somatodendritic tree, it is currently unclear how regional GABA receptors in the soma and dendritic compartments regulate spontaneous firing. Therefore, the objective of this study was to determine actions of regional GABA receptors on spontaneous firing in acutely dissociated DA neurons from the rat using patch-clamp and local GABA-uncaging techniques. Agonists and antagonists experiments showed that activation of either $GABA_A$ receptors or $GABA_B$ receptors in DA neurons is enough to completely abolish spontaneous firing. Local GABA-uncaging along the somatodendritic tree revealed that activation of regional GABA receptors limited within the soma, proximal, or distal dendritic region, can completely suppress spontaneous firing. However, activation of either $GABA_A$ or $GABA_B$ receptor equally suppressed spontaneous firing in the soma, whereas $GABA_B$ receptor inhibited spontaneous firing more strongly than $GABA_A$ receptor in the proximal and distal dendrites. These regional differences of GABA signals between the soma and dendritic compartments could contribute to our understanding of many diverse and complex actions of GABA in midbrain DA neurons.

• 대한물리의학회지
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• 제10권1호
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• pp.1-7
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• 2015

PURPOSE: The aim of this study was to investigate the effects of distal movement on shoulder muscle activation during diagonal pattern of exercises. METHODS: Seventeen healthy male participants volunteered to participate. Five muscles of shoulder were investigated during standing performance of diagonal shoulder exercises with and without visual trace. Two patterns of the diagonal exercises were used as diagonal 1 flexion and extension (D1F-E), and diagonal 2 flexion and extension (D2F-E). Two way repeated measures analysis of variance was used, which the factor was the presence of distal movement and exercise variations. RESULTS: The average muscle activity values of the lower trapezius and anterior deltoid are higher with the D2F-E, compared to the D1F-E (p<.05). The distal movement effect was observed within included all muscles except the lower trapezius, which the values are significantly greater in exercise with distal movement (P<.05). All significant increase of the muscles during the exercise with distal movement condition showed over 0.9 for the observed power in present study. CONCLUSION: Present result suggested that the diagonal pattern of exercise with distal movement has additional advantages of activating the scapulothoracic muscle as well as glenohumeral muscles. In addition, the D2F-E exercise pattern is effective for activating lower trapezius and anterior deltoid muscles.

• Annals of Clinical Neurophysiology
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• 제4권1호
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• pp.12-15
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• 2002

Background : Changes in firing pattern and in the recruitment order of single motor unit(MU) have been claimed to be characteristic of central motor lesions, and a reduced firing rate was found in upper motor neuron lesions. But these findings have been rarely studied before in Korea, so we studied initial MU recruitment pattern in stroke patients with hemiparesis. Methods : We studied six patients(3 men and 3 women) whose mean age was $60.6{\pm}7.4$ years. A mean $20.6{\pm}16.2$ months had elapsed since the stroke. To compare the initial MU activation patterns in proximal and distal segments of paretic limb with their contalateral unaffected counterparts, we studied the onset and recruitment intervals in biceps brachii(BB) and first dorsal interossei(FDI) muscles in paretic and healthy arms. In a single muscle we examined from 5 to 10 individual MUs. And in a single motor unit, both the onset interval and the recruitment interval was examined. Results : The mean onset interval in paretic limb was significantly(p<0.05) longer than unaffected limb at proximal and distal location: BB $118.5{\pm}17.8$ msec vs $96.1{\pm}8.3$ msec(n=58); FDI $125.8{\pm}16.7$ msec vs $101.5{\pm}17.2$ msec(n=38). The mean recruitment interval in paretic limb was also significantly(p<0.05) longer than unaffected limb: BB $87.7{\pm}14.9$ msec vs $73.4{\pm}11.5$ msec(n=53); FDI $96.3{\pm}16.4$ msec vs $87.7{\pm}14.1$ msec(n=38). Conclusion : The first recruited MU had a lower baseline firing rate and the second recruited motor unit potential appeared earlier in paretic than in healthy muscles. And these findings may explain one of the reasons for paresis in patients with stroke.

• 한국광학회지
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• 제25권4호
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• pp.200-206
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• 2014

본 논문에서는 직경 $125{\mu}m$의 싱글모드 광섬유에 입사된 빔을 다방향으로 방사하기 위하여 이론적으로 계산된 값을 광학설계 프로그램인 LightTools를 이용하여 광섬유 끝단에 원뿔형 구조물을 모델링 하고 입사된 모든 빔이 전반사 되어 측면으로 방사되는 광섬유 팁과, 전방과 측면으로 동시에 방사가 가능한 광섬유 팁에 대해 시뮬레이션을 하였다. 이러한 결과를 가지고 광섬유 끝단에 펨토초 레이저와 $CO_2$ 레이저를 이용하여 원뿔형 구조물을 제작하고 시뮬레이션 결과와 비교 분석하는 연구를 수행하였다.

• 대한치과의사협회지
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• 제49권11호
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• pp.660-669
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• 2011

Er: YAG laser irradiation utilizing the newly developed RCLase side-firing spiral tip was used for the cleansing of root canals following their bio-mechanical preparation with ProTaper Ni-Ti files. The distal and palatal roots of 20 freshly extracted molar teeth were instrumented to size F3 with ProTaper files. In the experimental group (10 teeth) the pulp chamber and the root canals were filled with EDTA 17% and the root canals were lased for 30 s using the Er: YAG laser irradiation at 600 mJ per pulse and a frequency of 12 Hz. In the control group (10 teeth) the root canals were not lased. Scanning electron microscope analysis showed clean wall surfaces of the lased root canals with open dentinal tubules, free of smear layer and debris. In the scanning electron microscope photographs of the walls of the non-lased root canals a considerable amount of debris could be detected. It appears that an efficient cleansing of the root canal system can be achieved by using the Er: YAG laser irradiation with the RCLase Side-firing Spiral Tip following bio-mechanical preparation of the root canal with Ni-Ti Taper files.

• 대한치과보철학회지
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• 제57권4호
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• pp.321-327
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• 2019

목적: 본 연구는 단일구조 지르코니아 크라운의 소결 후 소성 과정이 변연 및 내면 적합도에 미치는 영향에 대하여 3차원으로 평가해 보고자 하였다. 재료 및 방법: 타이타늄 지대치 모형을 제작하여 10개의 단일구조 지르코니아 크라운을 제작하였다. 제작된 단일구조 지르코니아 크라운을 소결 한 상태를 대조군으로, 소결 후 광택을 위해 추가적인 소성단계를 거친 후를 실험군으로 설정하였다. 각 군에서 triple-scan protocol을 이용하여 협설과 근원심으로 단면을 형성하고 변연 및 내면 적합도를 계측하여 통계 분석하였으며, 삼차원 표면 비교를 시행하였다 (${\alpha}=.05$). 결과: 변연과 내면 적합도를 분석한 결과 근심 축벽에서 대조군($32.0{\pm}24.3{\mu}m$)과 실험군 간($17.0{\pm}10.8{\mu}m$)의 통계적 유의한 차이가 있었고 (P < .020), 원심 축벽에서 대조군($60.2{\pm}24.3{\mu}m$)과 실험군($71.8{\pm}21.5{\mu}m$)간의 통계적으로 유의한 차이가 있었다 (P < .01). 나머지 측점지점에서는 통계적으로 유의한 차이가 없었다. 결론: 단일구조 지르코니아 크라운에서의 소결 후 추가적인 소성은 내면의 변형에 큰 영향을 미치지 않았고 임상적으로 허용 가능한 범위에 있었다.

• 대한치과보철학회지
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• 제36권1호
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• pp.120-132
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• 1998

This stusy was to investigate the marginal fitness of porcelain-fused-to- metal crown after succesive firing cycle. Main variables were the degree of marginal curvature of labiocervical margin and the type of alloy. The exaggerated marginal curvature(EMC) was created by additional reduction at the faciocervical wall of the normallized marginal curvature (NMC)-typed ivorine tooth by using milling machine. The difference in the shape was the mid facial margin was placed 2mm apical to cemento- enamel junction in labial surface. Three types of alloy were high noble, noble, and base metal alloy. Test specimens were divided into 8 groups and each group had 8 specimens. Sixty four ceramometal crowns were made totally. Measurement stages were following degassing, opaquing. body porcelain firing, and glazing, and measuring sites were 4. (midmesial, midfacial, middistal, and midlingual). Digital, travelling measuring microscope (0.5 um precision, Olympus. Japan) was used under ${\times}250$ magnification. Within the limitation of this investigation, it was concluded as belows: 1. The pattern of marginal distortion was varied. Degassing stage was not a specific, causative stage that induce most of total marginal distortion during whole procedure fabricating a ceramometal crown. Body firing stage induced discrepancy relatively more than other firing stages. 2. The specimens that were Ni-based alloy and had EMC were distorted persistently following successive fabricating procedures. But marginal openings were decreased after glazing. 3. The release of metal grinding-induced stress was presumed as a cause that induce marginal distortion. 4. The amount of discrepancies of the labial and lingual margins were greater than that of the mesial and distal margin in the specimen that had EMC. 5. Silver-plated die was not enough to resist abrasion during repeated seating of metal copings on the die-holding device.

• 한국정밀공학회지
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• 제30권10호
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• pp.1017-1022
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• 2013

Currently, various optical fiber tips are used to deliver laser beam for endoscopic surgery. In this paper, we demonstrated multidirectional (forward and side) firing optical fiber tip using a femtosecond micromachining and $CO_2$ laser polishing technology. We controlled the edge width of optical fiber tip, by modulating the condition of $CO_2$ laser, to regulate the amount of side and forward emission. The distal end of the optical fiber with core/clad diameter of $400/440{\mu}m$ was microstructured with cone shape by using a femtosecond laser. And then the microstructured optical fiber tip was polished by $CO_2$ laser beam result in smoothing and specular reflection at the surface of the cone structure. Finally, we operated the LightTools simulation and good agreement was generally found between the proposed model and experimental simulation.