구강상피세포의 냉동보관 방법에 따른 세포생존률 비교

백도영,이승종,정한성,김의성 대한치과보존학회 2009 Restorative Dentistry & Endodontics Vol.34 No.6

본 연구의 목적은 구강상피세포를 배양한후 각기 다른 조건의 냉동 보존법으로 6일간 보존시 각각의 세포의 활성도를 Cell counting, WST-1, Clonogenic capacity의 방법을 이용하여 비교 평가하기 위함이다. 각 실험군당 1×10^(6)개의 세포를 다음의 방법으로 6일간 냉동 보존한다. Freezing container에 담아 1℃/min의 냉동속도로 까지 냉동 후 -196℃에 냉동하여 보관한 일반 냉동 보존군, 세포를 바로 -196℃의 액화질소에 넣어 냉동한 급속 냉동 보존군, 4℃에서 -35℃까지 -0.5℃/min속도로 서서히 냉동시킨 뒤 -196℃에 냉동한 저속 냉동 보존군, 2 Mpa, 3 Mpa의 압력을 가하고 -0.5℃/min속도로 4℃에서 -35℃까지 서서히 냉동시킨 뒤 -196℃에 냉동한 2 Mpa, 3 Mpa압력 저속 냉동 보존군으로 나누었다. 6일 후 냉동되었던 세포를 급속 해빙하여 각각의 Cell counting, WST-1, Clonogenic capacity 값을 측정하여 비교하였다. 실험 결과 2 Mpa혹은 3 Mpa의 압력을 이용한 저속 냉동법이 저속 냉동법 및 급속 냉동법 보다 세포 활성도에 있어 우수한 경향을 나타내었다. This study examined the influence of the storage methods on the viability of oral epithelial cells using conventional cell freezing storage, slow freezing preservation, rapid freezing preservation, and slow freezing preservation with a pressure of 2 Mpa or 3 Mpa. The cell viability was evaluated by cell counting, WST-1 and the clonogenic capacity after 6 days of freezing storage. After 6 days, the frozen cells were thawed rapidly, and the cell counting. WST-1, and clonogenic capacity values were measured and compared. 1. The results from cell counting demonstrated that conventional cryopreservation, slow freezing under a 2 Mpa pressure and slow freezing under a 3 Mpa pressure showed significantly higher values than slow freezing preservation and rapid freezing preservation (p < 0.05). 2. The results from the optical density by WST-1 demonstrated that slow freezing under a 2 Mpa pressure showed significantly higher values than slow freezing preservation and rapid freezing preservation (p<0.05). 3. The clonogenic capacity demonstrated that slow freezing under a 2 Mpa pressure showed significantly higher values than slow freezing preservation and rapid freezing preservation (p < 0.05).

두개내 합병증을 유발한 저작극 농양

이상철,김여갑,류동목,이백수,최유성,한승완,오승환 大韓顎顔面成形再建外科學會 1996 Maxillofacial Plastic Reconstructive Surgery Vol.18 No.1

Although the use of the antibiotics has minimized the dangers of the spread of odontogenic infection to adjacent important organs, sometimes the fatal cases, such as Ludwig's angina, mediastinitis, intracranial complications from the odotogenic infection, may be occurred. The odontogenic infections or oral and maxillofacial region may involve the intracranial area through systemic circulation or by direct spread into the intracranial cavity. Headache, malaise, loss of appetite, chills, fever, vomiting, apathy, and irritability are usually followed by more specific involvement of the nervous system. We experienced one patient who died of intracranial complication from odontogenic infection. So we report the case and the literatures about intracranial involvements following odontogenic infections and dental procedures.

RUS법에 의한 Micro-Crack을 가진 Ferrule의 주파수 특성 평가

백경윤,이길성,양순호,김성훈,조영재,민한기,양인영 朝鮮大學校 機械技術硏究所 2003 機械技術硏究 Vol.6 No.2

광섬유 정렬부품으로 사용되는 페롤은 극히 높은 정밀도를 요하는 제품으로서, 높은 치수 정밀도와 결함이 포함되지 않는 등 높은 신뢰성이 요구되는 제품이다. 이러한 페롤의 형상결함평가에 종래의 광학현미경 평가법과는 달리. 본 논문에서는 공명초음파법(ResonantUltrasound Spectroscopy)을 이용하고자 한다. 공명초음파법이란 결함이 없는 시험편을 기계적으로 진동시켰을 때의 공진 주파수와 시험편 내에 결함을 가지고 있을 때의 공명 주파수 양상을 비교 분석하여 결함유무를 검출해내는 방법이다. 본 연구에서는 양품과 크랙을 가진 시험편을 현장에서 직접 사용되고 있는 광학현미경에 의해 분류를 한 다음, 더욱 정확한 측정을 위해 SEM에 의해 다시 분류하였다. 각각에 대해 공진 주파수를 측정하였고, 이 데이터의 검증을 위해 FEM해석을 수행하였다. 실험으로부터 얻는 양품의 공진 주파수와 FEM해석을 통해 얻었던 양품의 공진 주파수의 오차는 1∼2%정도의 범위를 벗어나지 않음을 알 수 있었다. 또한 크랙에 대한 공진 주파수를 측정하여서, 양품의 공진 주파수와 비교를 행하였고, 이 데이터를 가지고 모드별로 히스토그램을 그려서, 그것으로부터 현장에서 실제로 이용 가능한 모드를 존재함을 확인하였다. The Ferrule which is used as the product optical fiber very precisely, is required high to set the optical axes of an dimensional precision, lack of defect and high expectation. Up to now the optical instrument has been used for the defect and shape inspection of the Ferrule, but in this paper we examined the detectable defect and expectation by using the Resonant Ultrasound Spectroscopy (RUS). The RUS is the measurement' which is to excite specimen and to inspect the difference of natural frequency pattern between acceptable specimen and specimen has some defects. In this paper, we classified specimens into three groups by using She optical instrument; acceptable specimen A-type, 3-type and specimen A-type which has crack. And we reclassified by Scanning Microscope to carry out the more exact measurement. We surveyed the resonant frequency of every specimen, and carried out the simulation from the explicit finite elements code, NasEran t o verify the experiment data. The average error between the resonant frequency of acceptable specimens which is obtained from experiment and that from FEM analysis is in the range of 1-2 percentage. Also, we measured the resonant frequency of specimen which has crack, and compared that of acceptable specimen. We drew histogram by using these data, and confirmed the available mode in the plant.

하천 만곡률과 홍수량에 따른 수면경사도 산정

최한규,이문희,백효선 강원대학교 산업기술연구소 2006 産業技術硏究 Vol.26 No.A

In this research, we made a one and two-dimensional analysis of numerical data collected from the bend curvature of a bended river section. According to the result from the numerical analysis, the inflow & output angle caused a water level deviation which increased with an increase of the flood discharge. From the water level deviation of our two- dimensional numerical model, we obtained the maximum slope of 6,67% when the inflow and output angle was 105 degrees and the flood discharge was 500 CMS. As for the right side, the differences with the one-dimensional numerical model were reduced when the angle was more than 90˚. As for the left side the differences were reduced when the angle was more than 105˚. For a river with more than 90 degrees bend curvature, a hydraulic experiment would be more appropriate than a numerical analysis.

하천 만곡률과 홍수량에 따른 수면경사도 산정

최한규,이문희,백효선 강원대학교 산업기술연구소 2006 産業技術硏究 Vol.26 No.B

In this research, we made a one and two-dimensional analysis of numerical data collected from the bend curvature of a bended river section. According to the result from the numerical analysis, the inflow & output angle caused a water level deviation which increased with an increase of the flood discharge. From the water level deviation of our two-dimensional numerical model, we obtained the maximum slope of 6.67% when the inflow and output angle was 105 degrees and the flood discharge was 500 CMS. As for the right side, the differences with the one-dimensional numerical model were reduced when the angle was more than 90˚. As for the left side the differences were reduced when the angle was more than 105˚. For a river with more than 90 degrees bend curvature, a hydraulic experiment would be more appropriate than a numerical analysis.

분수로 분류부 형상에 따른 유량분배율 특성의 실험적 연구

최한규,백효선,이석환 江原大學校 産業技術硏究所 2002 産業技術硏究 Vol.22 No.A

The divided channel is not often used on the river and when the installation is for the controlling of the flow quantity. The determination of the channel size is not a easy task. Model tests are examined to confirm the variation of distribution rate by the method of the channel installation and the position of the structure and the adjustment of numerical simulation is executed by the comparing of the results. This study is to execute numerical model according to installation of divided channel by using AQUADYN program, the 2nd dimension numerical model, and HEC-RAS program, the 1st dimension numerical model, by the shape of divided channel. Also, it compares with difference by method about each case.

초음파법을 이용한 콘크리트 역타시공 이음부 공극의 화상검출특성

박석균,백운찬,이한범,김명모 한국비파괴검사학회 2000 한국비파괴검사학회지 Vol.20 No.4

최근 역타시공법 등에 의한 콘크리트 구조물의 시공이 증가 추세에 있다. 이 경우, 자주 발생되는 신ㆍ구타설 콘크리트 시공이음부의 공극은 향후 구조물의 구조적인 특성과 내구성 등에 큰 영향을 미치게 된다. 그러나 현재 제안되고 있는 비파괴 검사법으로는 효과적으로 이음부 공극을 평가하기에 많은 한계가 있다. 본 연구에서는 시공이음부의 콘크리트 충전상태를 평가하기 위해 철골철근 콘크리트와 무근 콘크리트 시험체내에 공극을 모의제작한 후, 초음파속도 측정을 실시하고, 화상처리기법을 이용하여 비교적 용이하게 해석 가능한 방법에 대해 검토하였다.

레진 계열 근관봉함재 Adseal의 세포독성에 관한 연구

김희정,백승호,이우철,박한수,배광식 大韓齒科保存學會 2004 Restorative Dentistry & Endodontics Vol.29 No.6

The properties of ideal root canal sealers include the ability of sealing the total root canal system and no toxic effects to periradicular tissues. Cytotoxicity test using cell culture is a common screening method for evaluation of the biocompatibility of root canal sealers. The purpose of this study was to investigate the cytotoxic effect of newly developed resin-based sealer (Adseal 1, 2, and 3) comparing with those commercial resin-based sealers (AH26 and AH Plus), ZOE-based sealers (Tubliseal EWT, Pulp Canal Sealer EWT) and calcium hydroxide based sealer (Sealapex). An indirect contact test of cytotoxicity by agar diffusion was performed according to the international standard ISO 10993-5. L929 fibroblast cells were incubated at 37℃ in humidified 5% CO₂-containing air atmosphere. The freshly mixed test materials were inserted into glass rings of internal diameter 5 ㎜ and height 5 ㎜ placed on the agar. After the 24 hrs incubation period, the decolorization zones around the test materials were assessed using an inverted microscope with a calibrated screen. A Decolorization Index was determined for each specimen. Adseal 1, 2, and 3 did not exert any cytotoxic effects, whereas AH26, AH Plus, Tubliseal EWT, Pulp Canal Sealer EWT, and Sealapex produced mild cytotoxicity.

초음파법을 이용한 콘크리트 시공이음부 공극 및 내부공동의 화상검출 해석에 관한 연구

박석균,백운찬,이한범 대전대학교 산업기술연구소 2000 산업기술연구소 論文集 Vol.11 No.2

The joint and void treatment of concrete is one of the technical problems in construction. Joints and voids created with the construction result in serious weakness from the aspects of both structural and water-barrier function. Ultrasonic image processing technique was used for the inspection of construction joints of SRC(Steel-frame Reinforced Concrete) column and voids of concrete block in this study. The advantages and limitations of this technique for non-destructive inspection in construction joints and voids are investigated. As a result, it has been verified that the semi-direct measurement type is more effective than the other types for detecting the construction joints and voids using ultrasonic method.

都心地 發破에서의 地盤振動 測定에 關한 硏究

金雄秀,林漢旭,李慶雲,徐栢洙 江原大學校 産業技術硏究所 1983 産業技術硏究 Vol.3 No.-

The blast vibrations were measured from 10 places through Seoul subway area to study their effects on the structures and to establish the safe blasting limits. For purpose of the present study, particle velocity only was recorded and analyzed, because it correlated most directly with damage. The results are as follows: (1) The proagation equation, V=K(D/W1/3)-n was obtained. Typical values could be found for n range from 1.7 to 1.5 and for k range from 48 to 138. (2) From the relationship between schmidt hammer rebound hardness and uniaxial compressive strength, Sc=0.514×(S.H)0.23, the compressive strength at any area can be assumed. (3) The use of AN-FO and other explosives with low detonation pressure may reduce vibration levels generated.