• 대한소아치과학회지
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• 제30권1호
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• pp.25-32
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• 2003

구강 질환으로 중요한 치아우식증은 구강 세균 중 Streptococcus mutans가 주 원인균이며, 치면에 부착, 증식 및 산생성 과정을 거쳐 치아우식을 유발한다. Streptococcus salivarius는 사람의 구강에 정상적으로 존재하는 세균이다. 본 연구에서는 소아의 구강으로 부터 분리된 9주의 S. salivarius의 특성과 S. mutans 및 Streptococcus oralis에 대한 영향을 연구하여 다음과 같은 결과를 얻었다. 1. 비커 와이어 검사에서 S. mutans 배양시 형성된 인공치태 무게는 204.9 mg이었으나, S. mutans와 분리된 S. salivarius의 혼합 배양시 형성된 인공치태 무게는 1.9 mg에서 20.6 mg으로 S. mutans 단독 배양시와 큰 차이가 있었다(p<0.05). 배양 후 생균수 검사에서는 큰 차이가 없었다. 2. M17 액체배지에서 배양된 분리균주의 배양 상청액을 가한 비커 와이어 검사에서 형성된 인공치태 무게는 평균 117.1 mg인데 반해, 5% 자당이 함유된 M17 액체배지에서 배양된 분리균주 배양 상청액을 가한 비커 와이어 검사에서는 평균 47.7 mg이었다. 3. 분리된 S. salivarius의 배양 상청액을 thin layer chromatography를 실시한 결과, 분리균주가 형성한 중합체는 프럭탄 (fructan)이었다. 4. 비커 와이어 검사에서 프럭탄의 일종인 inulin과 levan 모두 S. mutans의 인공치태 형성을 억제하지 못하였다. 이상의 결과를 종합하면 프럭탄을 생성하는 S. salivarius는 S. mutans의 인공치태 형성을 억제하였다.

• 한국지반신소재학회논문집
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• 제16권4호
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• pp.231-240
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• 2017

최근 도심지에서 인적, 물적 피해를 초래하여 경제적 손실을 수반하는 지반함몰이 빈번히 발생하고 있다. 이는 노후화된 상하수관거의 파손으로 인한 토사유실, 다짐불량, 수평굴착, 수직굴착시 토류벽 차수미흡 등 인위적 요인에 의하여 대다수 발생한다. 지반함몰은 탐사를 통하여 사전 복구 및 보강을 통해 예방이 가능하지만 현존하는 공법으로는 긴급복구에 적용하기에 어려움이 있다. 본 연구에서는 비개착식 지반공동 긴급복구 기술 개발을 위해 지하수흐름에 의한 지중 내 공동을 모사하는 모형실험을 진행하였으며, 조성된 공동 주변을 자체제작한 이완영역탐지기를 이용하여 탐지하므로써 이완영역 범위를 추정하였다. 또, 모사지반내 형성된 공동에 석고를 주입함으로써 교란영역과 이완영역을 구분하였다. 지하수 흐름에 의한 지중 공동의 형상은 선행연구 되었던 상수관거 파손시 내부 압력에 의해 조밀한 상대밀도의 지반에서 조성된 파괴모드III와 유사하였으며, 이완영역탐지기를 이용하여 탐지된 공동은 상부에서 아칭형태로 형성됨을 확인 할 수 있었다. 또한, 지반에서 공동 중심 상부에서 이완영역과 교란영역의 길이비는 2:1로 형성되며, 외력에 대한 전단저항력의 감소의 차이인해 구분될 수 있음을 확인하였다. 즉, 사전보수 및 보강시 주입재로 사용되는 재료의 팽창성을 고려하여 2차 피해가 발생되지 않도록 주의해야함을 확인 할 수 있었으며, 추후 추가적인 실험을 통하여 다양한 지반변형 상태를 추가로 실시할 예정이다.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.172-172
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• 2006

Molecular imprinting constitutes a valuable method of preparing polymeric materials with specific binding properties. The most conspicuous merit of molecular imprinting is that structurally three-dimensional recognition sites can be introduced into a polymer matrix with ease and low cost when compared with the complicated process of biological system for antigen and antibody. We used a thermally reversible bond for the preparation of the monomer-template complex, which allowed us to remove the template easily by means of a simple thermal reaction and to simultaneously introduce various functional groups into the cavity. This method is especially propitious for developing artificial receptors for molecules lacking strongly interactive groups.

• Journal of electromagnetic engineering and science
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• 제9권4호
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• pp.211-217
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• 2009

A three-dimensional locally one-dimensional multiresolution time-domain(LOD-MRTD) method is introduced and unconditional stability is proved analytically. The updating formulations have fewer terms on the right-hand side than those of an alternating direction implicit MRTD(ADI-MRTD). The validation of the method is presented using the resonance frequency problem of an empty cavity. The reduction of the numerical dispersion technique is also combined with the proposed method. The numerical examples show that the combined method can improve the accuracy significantly.

• 한국가시화정보학회지
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• 제2권2호
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• pp.3-7
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• 2004

In this paper, computational aeroacoustics (CAA) method is used for flow-noise analysis and flow-noise visualization. High order high resolution scheme of optimized high order compact is used to resolve the small acoustic quantities and large flow quantities at the same time. An adaptive nonlinear artificial dissipation model and generalized characteristic boundary condition are also used. Aeolion tone noise, cavity noise, and jet noise are investigated. The visualizations of flow-noise are successful and characteristics of noise are studied. It is observed that the propagation directivity of noise is different with that of flow. With the help of CAA method, the visualization of noise is possible.

• 한국임상수의학회지
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• 제9권2호
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• pp.451-456
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• 1992

The 2% Sodium carboxymethylcellulose(CMC) and 10% Dextran 70 solutions were evaluated for the prevention of postoperative adhesion formation in rats. The artificial injuries(2cm longitudinal incision and suture) were performed on the colon and uterine horns in the rats. 2% CMC and 10% dextran solutions were applied to the injured surfaces and peritoneal cavity in the rats. Ten days later, there were significant difference(p<0.01) in the prevention of adhesion formation between control and treated groups(2% CMC and 10% dextran 70), but the,$\boxUl$ was no significant difference between 2% CMC and 10% dextran 70 treated groups. The increment rate of body weight in the 10% dextran 70 treated group was lower than 2% CMC and control groups(p<0.05.). A positive correlation was found between the severity of adhesion formation and the plasma fibrinogen concentration in blood.

• Journal of Yeungnam Medical Science
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• 제37권3호
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• pp.169-178
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• 2020

Glass ionomer cement (GIC) is a tailor-made material that is used as a filling material in dentistry. GIC is cured by an acid-base reaction consisting of a glass filler and ionic polymers. When the glass filler and ionic polymers are mixed, ionic bonds of the material itself are formed. In addition, the extra polymer anion reacts with calcium in enamel or dentin to increase adhesion to the tooth tissue. GICs are widely used as adhesives for artificial crowns or orthodontic brackets, and are also used as tooth repair material, cavity liner, and filling materials. In this review, the current status of GIC research and development and its prospects for the future have been discussed in detail.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2002년도 생물공학의 동향 (X)
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• pp.139-144
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• 2002

Two types of alginate gel beads capable of floating in the gastric cavity were prepared. The first, alginate gell bead containing olive oil(Al-Oil), is a hydrogel bead and its buoyancy is attributable to olive oil held in the alginate gel matrix. The model drug, metronidazole(MZ), contained in Al-Oil was released gradually into artificial gastric fluid. The profiles of MZ release from Al-Oil shown initial burst and after 90 min they were about 100%. The second, alginate gel bead containing curdlan microsphere(Al-C), is a gel bead with curdlan-MZ microsphere in the matrix. To sustained release rate of drug, alginate bead were prepared curdlan microsphere containing MZ. Results demonstrated that sustained delivery of MZ over 2h can be easily achieved while the bead remained float. The release properties of prepared alginate beads are applicable not only for sustained release of drugs but also for targeting the gastric mucosa.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 춘계학술대회 논문집
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• pp.198-203
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• 1995

In the paper, we have proposed a new technique to detemine the initial billet for the forged products using a function approximation in neural network. A three-layer neural network is used and a back propagation algorithm is employed totrain the network. An optimal billet which satisfied the forming limitation, minimum of incomplete filling in the die cavity, load and energyas well as more uniform distribution of effective strain, is determined by applying the ability of function approximation of te neural network. The amount of incomplete filling in the die, load and forming energyas well as effective strain are measured by the rigid-plastic finite element method. The new technique is applied tofind the optimal billet size for the axisymmetric rib-web product in hot forging. This would reduce the number of finite element simulation for determing the optimal billet of forging products, further it is usefully adapted to physical modeling for the forging design.

• 한국수정란이식학회:학술대회논문집
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• 한국수정란이식학회 2006년도 The 6th Intermational Symposium on Developmental Biotechnology
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• pp.84-85
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• 2006