적외선열화상장치를 이용한 Buchanan plugger 표면의 온도상승 분석

최성아,김선호,황윤찬,윤창,오병주,최보영,정우남,정선와,황인남,오원만 大韓齒科保存學會 2002 Restorative Dentistry & Endodontics Vol.27 No.4

This study was performed to evaluate the temperature rise on various position of the Buchanan plugger, the peak temperature of plugger's type and the temperature change by its touching time of heat control spring. The heat carrier system 'System B' (Model 1005. Analytic Technologies, USA) and the Buchanan's pluggers of F, FM, M and ML sizes are used for this study. The temperature was set to 200℃ which Dr. Buchanan's "continuous wave of condensation" technique recommended on digital display and the power level on it was set to 10. In order to apply heat on the Buchanan's pluggers, the heat control spring was touched for 1, 2, 3, 4 and 5 seconds respectively. The temperature rise on the surface of the pluggers were measured at 0.5 mm intervals from tip to 20 mm length of shank using the infraed thermography (Radiation Thermometer-IR temper, NEC San-ei Instruments, Ltd, Japan) and TH31-702 Data capture software program (NEC San-ei Instruments, Ltd, Japan). Data were analyzed using a one way ANOVA followed by Duncan's multiple range test and linear regression test. The results as follows. 1. The position at which temperature peaked was approximately at 0.5 mm to 1.5 mm far from the tip of Buchanan's pluggers (p<0.001). The temperature was constantly decreased toward the shank from the tip of it(p<0.001). 2. When the pluggers were heated over 5 seconds, the peak temperature by time of measurement revealed from 253.3±10.5℃ to 192.1±3.3℃ in a touch for 1 sec, from 218.6±5.0℃ to 179.5±4.2℃ in a touch for 2 sec, from 197.5±3.0℃ to 167.6±3.7℃ in a touch for 3 sec, from 183.7±2.5℃ to 159.8±3.6℃ in a touch for 4 sec and from 164.9±2.0℃ to 158.4±1.8℃ in a touch for 5 sec. A touch for 1 sec showed the highest peak temperature, followed by, in descending order, 2 sec, 3 sec, 4 sec. A touch for 5 sec showed the lowest peak temperature (p<0.001). 3. A each type of pluggers showed different peak temperatures. The peak temperature was the highest in F type and followed by, in descending order, M type, ML type. FM type revealed the lowest peak temerature (p<0.001). The results of this study indicated that pluggers are designed to concentrate heat at around its tip, its actual temperature dose not correlate well with the temperature which Buchanan's "continuous wave of condensation" technique recommended, and finally a quick touch of heat control spring for 1 sec reveals the highest temperature rise.

고혈압성 위기의 치료

최영진,오병희 대한고혈압학회 1997 대한고혈압학회지 Vol.3 No.2

Paraquat 유도 간독성에 대한 Hydroxycinnamic acid계 화합물의 독성 경감 효과 (Ⅱ)

최병기,오은정 한국환경독성학회 1999 환경독성보건학회지 Vol.14 No.3

Antioxidative and scavenging effects were investigated by using two hyaroxycinnamic acids (caffeetannins), such as caffeic acid and chlorogenic acid, on oxidative stress and hepatotoxicity that induced by paraquat. The results are summerized as follows: 1. To assess radical scavenging ability, reduction concentration (IC_(50)) of 1.1 diphenyl-2-dipicrylhydrazine (DPPH) were measured. IC_(50) values of caffeic acid and chlorogenic acid were 29.7±0.6μM and 26.0± 0.5μM respectively. Their radical scavenging activities showed concentration-dependent manner. 2. In H₂0₂-induced hemolysis assay to rat blood, caffeic acid and chlorogenic acid led to different effects, whose hemolysis inhibition ratios at 100 μM were 45.2±7.1 % and 11.6±3.1 % respectively. 3. In hypoxanthine-xanthine oxidase system producing superoxide anion, caffeic acid and chlorogenic acid showed different inhibitory activities of xanthine oxidase showing 36.8±4.3% and 5.4±2.3% respectively. 4. To microsomal NADPH dependent cytochrome p-450 reductase in rat liver, paraquat consumed NADPH at a dose-dependent manner from 0 to 1 μM paraquat concentration. Caffeic acid and chlorogenic acid blocked NADPH consumption rates at concentration-dependent manner and inhibition ratios at 100 μM were 67.6%% and 59.2% respectively. 5. Administration (30mg/kg, iv) of paraquat to rats caused the marked elevation of glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and lipid peroxides (LPO) in the serum and lipid peroxides in the microsome as compared to the control group. Serum GOT, GPT, LDH, ALP and LPO and liver microsomal LPO were reduced significantly by caffeic acid (50mg/kg), chlorogenic acid (25mg/kg) and silymarin (150mg/kg) as compared to the paraquat group. From these results, caffeic acid and chlorogenic acid exerted their antioxidative agents by removing reactive oxygen substance (ROS) and scavenging effects by inhibiting ROS generating enzyme. As a general, two hydroxyeinnamic acids showed the useful compounds for scavenger and reducer on the paraquat induced hepatotoxicity.

유절기 조기 상실 후 공간 상실

최병재,한연선,김성오,이종갑 大韓小兒齒科學會 2002 大韓小兒齒科學會誌 Vol.29 No.3

유치에서의 조기 상실은 부위에 따라 주된 원인이 다르다. 구치부의 조기 상실은 주로 치아우식증에 의해 일어나지만, 전치부에서 나타나는 조기 상실의 대부분은 유아가 서고 걷는 것을 배울 시기에 외상을 받아 유발되며, 다발성 우식증 등에 의해서도 일어날 수 있다. 유치의 조기 상실시 치열궁 길이 감소가 나타날 경우에는 계승 영구치의 맹출을 방해하여 영구치의 총생, 매복 및 치열궁 비대칭 등을 유발할 수 있으므로, 공간 유지에 대한 고려가 필요하다. 유구치가 조기 상실된 경우에는 인접치아의 근심 또는 원심 이동으로 공간 상실이 유발되므로, 공간유지장치의 장착이 필수적이다. 그러나, 유절치의 경우에 있어서는 치아간의 접촉이 긴밀하거나 총생이 있는 유치열이 경우와 유견치의 맹출 전에 유절치가 상실된 경우에는 공간 상실이 일어날 수 있으나, 그 이외에 치간 공간이 있는 유치열이 경우, 유견치의 맹출 후에 유절치가 상실된 경우에서는 공간의 상실이 거의 없는 것으로 알려져 있다. 따라서 유절치 조기 상실 시에는 주로 공간유지 목적보다는 심미, 발음장애, 치아결손부분으로의 혀내밀기 등의 구강습관 방지 등의 목적으로 장치의 장착이 권장되어져 왔으며, 유절치 조기 상실시 공간 상실 문제에 대한 증례보고 또한 많지 않다. 본 증례들은 연세대학교 치과대학병원 소아치과에 내원한 환자에게서 유절치의 조기 발거로 인해 장기적 관찰 결과 공간 상실이 유발되었기에 이를 통하여 유절치 조기 상실시 공간 상실 가능성에 대해 보고하고자 한다. The primary cause of missing teeth vary depending on the region. The loss of posterior teeth is mainly due to dental caries, whereas that of the anterior teeth occur primarily due to trauma at the age of standing and walk-ing and secondarily from the rampant dental caries. Particularly, reduction of the arch length in the cases of premature loss of primary teeth may compromise the eruption of succedaneous permanent teeth. This may result in crowding and impaction of the permanent teeth, and asymmetry of arch, thus a careful consideration for space maintenance should be made in such cases. Space maintainer is required in the case of premature loss of primary posterior teeth, because space loss result from the approximate and centrifugal movement of the neighboring teeth. Generally, in the case of primary in-cisor, space loss occurs when 1) tooth contact is relevant, 2) crowding in primary dentition is present, and 3) a primary incisor is lost before the eruption of primary canine. Contrarily, in the case of primary dentition with in-terdental space, space loss will not be observed, mostly when a primary incisor is lost after the eruption of pri-mary canine. Thus, using a space maintainer in cases of premature loss of primary incisor has been introduced primarily not for the purpose of space maintaining but for an aesthetic purpose, prevention of parafunctional oral habits such as tongue thrust, and of pronunciation. Additionally, few case studies have been reported of space loss in cases of premature loss of primary incisor. This study is to report cases of the space loss following the premature loss of primary incisors observed in chil-dren.

코크스 폐수를 이용한 활성슬러지 모델 파라미터의 민감도 분석

오재일,이병준,심효영,최상교 대한상하수도학회 2002 상하수도학회지 Vol.16 No.3

Activated sludge model (ASM, IAWQ Task Group) was developed as a general mathematical model to express major biological processes in municipal wastewater treatment. Therefore this model could be applied for the design of a wastewater treatment plant and used for finding optimal conditions in plant operation. Since biological processes adopting biodegradation have been also used to treat lots of industrial wastewater such as coke's wastewater, it is worthy to examine the applicability of ASM on the industrial wastewater treatment. In order to evaluate this possibility, the sensitivity analysis of seven parameters (Y_H,μ_H, b_H, k_h, K_S, K_(O,H), K_x) in ASM was conducted with regard to the SCOD (soluble chemical oxygen demand) removal in coke's wastewater treatment. It has shown that μ_H (maximum specific growth rate) of ASM was the most sensitive one in the SCOD removal process, and relative sensitivity was decided in order of μ_H >> b_H, K_S > Y_H, K_(O,H), K_h, K_x, consequently. Based on the sensitivity analysis and calibration procedure of ASM with the data from coke's plant, the decided parameter values were valid for the proper simulation of this industrial wastewater plant, showing adequate fitting between real and simulated data. In summary, the mathematical model of ASM was suitable for the simulation of coke's wastewater treatment plant.

고속 가공기의 스핀들 진동에 영향을 주는 요소 분석

최영호,윤두표,김광영,최병오 한국공작기계학회 2001 한국공작기계학회 춘계학술대회논문집 Vol.2001 No.-

In this paper, We have studied on the critical vibration limits of spindle unit for the high speed ball pen tip processing machine. The vibration of bearing can be measured by FFT, and the influence of vibration amplitude due to the Unbalance, bearing deflect, bite and timing belts tension are analyzed. So, the critical vibration limits of spindle is determined by the X, Z directional vibration of spindle Unit.

우리나라 感潮河川 水位資料의 初基分析

崔秉昊,徐景錫,吳允根 成均館大學校 科學技術硏究所 1987 論文集 Vol.38 No.2

우리나라 主要河川의 感潮區間에서의 水位觀測은 1910年代부터 시작되었으나 感潮區間의 潮汐變化를 判別키 위한 이 長期資料의 徹底한 分析은 遂行된 바 없다. 本 硏究에서는 利用可能한 漢江, 錦江感潮區間에서의 5個所(顚類, 金浦大橋, 玉浦, 笠浦, 江景)의 感潮水位資料를 分析하기 위한 初期努力이 試圖되었다. 原記錄曲線으로부터 每時間別로 編輯된 水位資料로부터 統計的 變數들과 潮汐의 調和常敎를 구했는데 檢討結果에 의하면 旣存水位資料들은 不適合한 觀測體系 및 記錄體系 때문에 資料의 質은 극히 不良하였다. Observations of the water levels in the tidal reaches of major rivers in South Korea have been made since 1910s. But these extended records have never been subjected to intensive analysis to identify the tidal variation in the shallow rivers. In the present study, an initial attempt was made to analyze the available tidal data at five gauging stations(Jeonryu, Kimpo Bridge, Okpo, lbpo and Ganggyeong) in the Han River and the Keum River. Statistical parameters and harmonic constants were obtained from edited hourly water levels taken from original water level curves. It was found that existing data were seriously corrupted by improper measurement and recording system.

Silicone die를 이용한 교합면우식증의 composite resin inlay 치료증례

최병재,손흥규,김성오 大韓小兒齒科學會 1992 大韓小兒齒科學會誌 Vol.19 No.2

In the past, the goals of dental treatment were to relieve pain and to intercept disease processing. Nowadays, however, food, clothing and housing have been promoted and dental considerations for restoring esthetic and masticatory function have become increased. Therefore several esthetic restoration techniques for posterior teeth were developed : direct resin filling, porcelain inlay/onlay and composite resin inlay/onlay. The purposes of this article are to review the problems and the improvements of direct resin filling techniques on posterior teeth and to report a case of composite resin inlay technique with silicone materials on posterior tooth. The problems of conventional direct resin filling techniques are severe occlusal wear, microleakage from polymerization shrinkage, recurrent caries, poor proximal contact, isthmus fracture, postoperative sensitivity, poor radiopacity, ect. In order to solve these problems, complete polymerization on comnposite resin is needed. Therefore resin inlay technique is developed with additional light, heat and pressure curing. Although physical properties(wear resistence, tensile strength, etc.) have been improved with composite resin inlay technique, the procedures are complicated and time consuming. On this report, we improved the fabrication of composite resin inlay with silicone rubber base materials.

치아 순면 형태가 측색 기기를 이용한 치아 색상 측정 결과에 미치는 영향

최용진,박수정,조현구,황윤찬,오원만,박병주,황인남 대한치과보존학회 2007 Restorative Dentistry & Endodontics Vol.32 No.5

Paraquat 유도 폐독성에 대한 Hydroxycinnamic Acid계 화합물의 독성 경감 효과 (Ⅲ)

최병기,오은정,정세영 한국환경독성학회 1999 환경독성보건학회지 Vol.14 No.3

The scavenging effects of two hyaroxycinnamic acids such as caffeic acid and chlorogenic acid on paraquat induced pulmonary toxicity were investigated. The results are summerized as follows: 1. In the 5-lipoxygenase assay, caffeic acid and chlorogenic acid inhibited the enzyme activities whose inhibition concentration (IC_(50)) were 4.1 and 9.6 μM respectively. 2. To evaluate the antiinflammatory effects on mediator related to the mechanism of inflammation, ADP-induced platelet aggregation assay and histamine degranulation assay were used. Caffeic acid and chlorogenic acid inhibited on ADP-induced platelet aggregation and histamine release at a concentration dependent manners. 3. Arachidonic acid--induced ear edema were inhibited by administration of caffeic acid and chlorogenic acid. 4. Cytologicad analysis of branchoalveolar lavage fluid (BALF) which was the useful tool for detection of an inflammatory response in the lungs of animals intoxicated with chemicals were used. Alveolar macrophages and neutrophils in BALF, as well as the protein content and the LDH activity in BALF supernatant increased by intoxication of paraquat, but decreased by administration of caffeic acid and chlorogenic acid. Therefore, two hydroxyeinnamic acids tested were the useful candidates for scavenger and antiinflammatory agents on paraquat induced pulmonary toxicity.