• 열처리공학회지
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• 제16권1호
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• pp.26-31
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• 2003

Decarburized zone of metal tongue which is used in seat belt for automobiles was carbon-restoration quenched and tempered using nitrogen-methanol gaseous atmosphere. The effects of microstructure and mechanical properties of metal tongue on the effectiveness of carbon-restoration during tempering was studied. Metal tongue showed $20{\sim}30{\mu}m$ decarburized zone. However, after carbon-restoration, it has uniform microstructure and thus hardness without decarburized zone. Carbon-restoration quenching and tempering process resulted in better wear and corrosion resistances than quenching and tempering process.

• 전기화학회지
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• 제7권4호
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• pp.206-210
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• 2004

금속산화물 $(TiO_2,\;RuO_2,\;PbO_2,\;Ni(OH)_2)$과 Prussian blue (PB)를 각각 탄소반죽에 혼합한 후 스크린 프린팅 기법으로 6종의 탄소반죽 전극들을 제작하였다. 제작된 탄소반죽 전극들로 전자혀 시스템을 제작하여 다양한 음료수와 식품에 대한 감응을 0.1M carbonate buffer, pH 9.6완충 용액에 묽힌 후 대시간전류법의 방법으로 측정하였다 얻어진 자료를 주성분 분석법 (principal component analysis; PCA)으로 처리한 후 식음료의 맛을 평가할 수 있도록 2차원 좌표계에 표시하였으며, 그 결과 본 실험에서 제작한 시스템 및 분석법은 다양한 식음료의 종류를 뚜렷이 구분해 낼 수 있음을 확인하였다.

• 대한치과보철학회지
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• 제56권4호
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• pp.317-322
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• 2018

혀는 구강 내에서 가장 흔하게 종양이 발생하는 부위이며, 특히 측면에서 호발한다. 설암으로 인해 혀의 절제를 시행한 환자의 경우 발음, 저작, 연하 그리고 구강 위생을 위해 적절한 움직임 등의 기능에 장애를 갖게 되므로 적절한 혀의 기능을 회복하기 위해 구개 증대 보철물을 이용할 수 있다. 본 증례는 설암으로 인해 혀의 절제를 시행한 환자에서 치조설열구 및 치조제 소실 등의 불리한 조건을 임플란트를 이용한 피개의치를 이용하여 개선하였다. 또한 금속 하부구조와 지지 및 유지부를 갖는 형태의 구개 증대 보철물을 제작하여 구개 높이를 낮추어 줌으로써 제한된 혀의 운동으로도 적절한 혀구개 접촉을 얻을 수 있었다. 최종보철물 장착 후 안정적인 저작기능을 회복하였고 연하 및 발음의 문제가 개선되어 이를 보고하고자 한다.

• 센서학회지
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• 제14권5호
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• pp.357-361
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• 2005

Low-stress silicon nitride (LSN) thin films with embedded metal line have been developed as free standing structures to keep microspheres in proper locations and localized heat source for application to a chip-based sensor array for the simultaneous and near-real-time detection of multiple analytes in solution. The LSN film has been utilized as a structural material as well as a hard mask layer for wet anisotropic etching of silicon. The LSN was deposited by LPCVD (Low Pressure Chemical Vapor Deposition) process by varing the ratio of source gas flows. The residual stress of the LSN film was measured by laser curvature method. The residual stress of the LSN film is 6 times lower than that of the stoichiometric silicon nitride film. The test results showed that not only the LSN film but also the stack of LSN layers with embedded metal line could stand without notable deflection.

• 대한치과보철학회지
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• 제57권4호
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• pp.350-355
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• 2019

성공적인 총의치를 위해서는 유지, 안정, 지지 세가지 요소가 필수적으로 요구된다. 또한 심한 치조제의 흡수나 수술에 의한 반흔으로 인해 하악 설측변연 형성이 어려운 총의치 제작시에는 무교두 치아배열, 연마면 인상, 무게 보강 내부금속 삽입, 의치 접착 크림의 사용 등의 다양한 고려사항이 필요하다. 본 환자의 경우 심한 치주염으로 심하게 골흡수가 된 무치악 치조제를 가졌고, 또한 설암으로 인한 설절제술로 인해 연조직의 문제를 가진 환자이다. 부가적인 유지와 안정을 얻기 위해 연마면 인상과 내부 보강 금속구조물의 삽입 그리고 최소 가압 인상 등의 방법을 적용하여 보다 나은 임상적 결과를 나타내었다. 또한 원하는 3차원적 형태를 정확하게 부여하고 제작시 복잡한 기공과정을 줄인 금속 구조물을 제작하기 위해 최소 가압 인상 채득과 Direct metal laser sintering이 사용되었다.

• Imaging Science in Dentistry
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• 제51권1호
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• pp.63-71
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• 2021

Purpose: The aim of this study was to assess the artefacts of 12 fixed orthodontic appliances in magnetic resonance images obtained using 1.5-T and 3-T scanners, and to evaluate different imaging sequences designed to suppress metal artefacts. Materials and Methods: In vitro, study casts of 1 adult with normal occlusion were used. Twelve orthodontic appliances were attached to the study casts and scanned. Turbo spin echo (TSE), TSE with high readout bandwidth, and TSE with view angle tilting and slice encoding for metal artefact correction were used to suppress metal artefacts. Artefacts were measured. In vivo, 6 appliances were scanned: 1) conventional stainless-steel brackets; 2) nickelfree brackets; 3) titanium brackets; 4) a Herbst appliance; 5) a fixed retainer; and 6) a rapid maxillary expander. The maxilla, mandible, nasopharynx, tongue, temporomandibular joints, and cranial base/eye globes were assessed. Scores of 0, 1, 2, and 3 indicated no artefacts and minor, moderate, and major artefacts, respectively. Results: In vitro, titanium brackets and the fixed retainer created minor artefacts. In vivo, titanium brackets caused minor artefacts. Conventional stainless-steel and nickel free brackets, the fixed retainer, and the rapid maxillary expander caused major artefacts in the maxilla and mandible. Conventional stainless-steel and nickel-free brackets caused major artefacts in the eye globe (3-T). TSE with high readout bandwidth reduced image artefacts in both scanners. Conclusion: Titanium brackets, the Herbst appliance, and the fixed retainer caused minor artefacts in images of neurocranial structures(1.5-T and 3-T) when using TSE with high readout bandwidth.

• 대한소아치과학회지
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• 제32권1호
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• pp.101-108
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• 2005

혼합 치열기에서 유치의 탈락 및 영구치의 맹출 과정이 순조롭게 이루어지는 것은 중요한 일이다. 맹출 중인 치아는 인접치 유무, 유치의 흡수속도, 유치의 조기상실, 만기잔존, 국소병소나 입술, 혀, 저작근 등의 다양한 요인들에 의해 영향 받을 수 있으며, 이러한 요소들 사이의 균형이 깨지게 되면 인접치 간의 관계가 변하고 심각한 부정교합이 초래될 수 있다. 본 증례는 유치열 및 혼합치열을 가진 어린이들에서 상하악 구치부 교합면에 접착된 교합 거상 금속 스플린트(bite raising metal splint)가 치열에 미친 영향에 대해 보여주고 있다. 이들은 스플린트로 인한 유치의 만기잔존으로 영구치 맹출에 방해를 받거나, 전치부 개방교합, 제 1대구치의 저위 맹출 등 혼합 치열기 발달에 큰 영향을 받고 있었다. 치료로써 고속 핸드피스를 이용하여 스플린트를 제거하고 주기적 점검을 통해 교합변화 및 영구치 맹출 양상을 관찰하였다.

• Imaging Science in Dentistry
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• 제50권4호
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• pp.291-298
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• 2020

Purpose: The detection and exact localization of penetrating foreign bodies are crucial for the appropriate management of patients with dentoalveolar trauma. This study compared the efficacy of cone-beam computed tomography (CBCT) and spiral computed tomography (CT) scans for the detection of different foreign bodies composed of 5 frequently encountered materials in 2 sizes. The effect of the location of the foreign bodies on their visibility was also analyzed. Materials and Methods: In this in vitro study, metal, tooth, stone, glass, and plastic particles measuring 1×1×1 mm and 2×2×2 mm were prepared. They were implanted in a sheep's head in the tongue muscle, nasal cavity, and at the interface of the mandibular cortex and soft tissue. CBCT and spiral CT scans were taken and the visibility of foreign bodies was scored by 4 skilled maxillofacial radiologists who were blinded to the location and number of foreign bodies. Results: CT and CBCT were equally accurate in visualizing metal, stone, and tooth particles of both sizes. However, CBCT was better for detecting glass particles in the periosteum. Although both imaging modalities visualized plastic particles poorly, CT was slightly better for detecting plastic particles, especially the smaller ones. Conclusion: Considering the lower patient radiation dose and cost, CBCT can be used with almost equal accuracy as CT for detecting foreign bodies of different compositions and sizes in multiple maxillofacial regions. However, CT performed better for detecting plastic particles.

• BMB Reports
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• 제38권5호
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• pp.584-590
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• 2005

Glucose 6-phosphate dehydrogenase (EC 1.1.1.49) was purified from Aspergillus aculeatus, a filamentous fungus previously isolated from infected tongue of a patient. The enzyme, apparently homogeneous, had a specific activity of $220\;units\;mg^{-1}$/, a molecular weight of $105,000{\pm}5,000$ Dal by gel filtration and subunit size of $52,000{\pm}1,100$ Dal by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The substrate specificity was extremely strict, with glucose 6-phosphate (G6P) being oxidized by nicotinamide adenine dinucleotide phosphate (NADP) only. At assay pH of 7.5, the enzyme had $K_m$ values of $6\;{\mu}m$ and $75\;{\mu}m$ for NADP and G6P respectively. The $k_{cat}$ was $83\;s^{-1}$. Steady-state kinetics at pH 7.5 produced converging linear Lineweaver-Burk plots as expected for ternary-complex mechanism. The patterns of product and dead-end inhibition suggested that the enzyme can bind NADP and G6P separately to form a binary complex, indicating a random-order mechanism. The enzyme was irreversibly inactivated by heat in a linear fashion, with G6P providing a degree of protection. Phosphoenolpyruvate (PEP), adenosinetriphosphate (ATP), and fructose 6-phosphate (F6P), in decreasing order, are effective inhibitors. Zinc and Cobalt ions were effective inhibitors although cobalt ion was more potent; the two divalent metals were competitive inhibitors with respect to G6P, with $K_i$ values of $6.6\;{\mu}m$ and $4.7\;{\mu}m$ respectively. It is proposed that inhibition by divalent metal ions, at low NADPH /NADP ratio, is another means of controlling pentosephosphate pathway.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제28권6호
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• pp.413-420
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• 2002

Mercury is one of the most frequently used heavy metal in dental clinic. Mercury poisoning rises up when someone is exposed to mercury chronically. In 1818, Amalgam was used for dental restorative procedure, and after then study about mercury toxicity has begun. Clinical signs of mercury toxicity in oral & maxillofacial area were increases of salivation, metallic taste, swelling and pain of tongue, redness and ulceration of oral mucosa, and increased mobility and loss of teeth. After we injected mercury($HgCl_{2}$) into intraperitoneum of rat, studied about histopathological changes of submandibular gland cell. Experimental group was divided into two groups by amount of mercury. (Group 1 was 0.5mg/Kg of mercury injection, group 2 was 1.0mg/Kg of mercury injection.) 1. After 3days of intraperitoneal injection, black granules were observed at macrophage cell in both group. In group 2, author found hyperchromatism of nucleus, and vacuolization of cellular matrix and nucleus of acinar cell. 2. After 1week of intraperitoneal injection, author found severe vacuolization of nucleus and cellular matrix, and irregular granules around nuclear membrane at mucous cell and serous cell in both group. Vacuolization of nucleus and cellular matrix was seen at duct cell in group 2. 3. After 2weeks of intraperitoneal injection, author could found severe vacuolization of cellular matrix, and sometimes nucleus was positioned in central area of cellular matrix at mucous and serous cell in both group. Vacuolization of nucleus and cellular matrix was found at vascular endothelial cell in group 2. 4. After 4weeks of intraperitoneal injection, destruction and distortion of gland cells were distinct. Vacuolization and destruction of nucleus and cellular matrix was found at duct cell in group 2. After intraperitoneal injection of mercury, we found equanimity of mercury and destruction of cellular matrix at serous cell, mucous cell, and duct cell of submandibular gland. So, we thought that metallic taste of mercury poisoning patient would be due to excretion of saliva containing mercury.