• 대한소아치과학회지
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• 제39권1호
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• pp.73-78
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• 2012

복잡 치아종은 치아와 해부학적인 유사성이 없는 법랑질, 상아질, 백악질의 덩어리로 구성되어 있다. 이 병소의 대부분은 증상이 없어 일상적인 방사선 검사나 치아의 맹출 실패의 원인을 감별하기 위한 검사를 통해 발견된다. 복합 치아종은 골 팽창을 보이는 경우가 드물지만, 복잡 치아종은 경미하거나 뚜렷한 골 팽창을 보인다. 복잡 치아종은 거의 영구치와 연관되어 있고 유치와 연관된 경우는 매우 드물다. 이는 보통 하악의 유구치 부위에 발생한다. 본 증례는 상악 유견치의 매복과 연관된 복잡 치아종을 외과적 방법으로 제거하고 자가맹출을 용이하게 하기 위해 치은 하방에 재위치 시켰다. 수술 6개월 후에 상악 유견치가 자가 맹출되었으므로 이를 보고한다.

• 한국재료학회지
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• 제15권8호
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• pp.528-535
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• 2005

It is inclined to increase that use of hazardous substances such as lead(Pb), mercury (Hg), cadmium(Cd) etc. are prohibited in the electronics according to environmental friendly policies of an advanced nation for protecting environment of earth. As this reasons, many researches for ensuring the reliability were proceeding in Pb free soldering process. n the flux remains on the PCB(printed circuit board) in the soldering process or the electronics exposed to corrosive environment, it becomes the reasons of breakdown or malfunction of the electronics caused by corrosion. Therefore in this studies we researched the polarization and Tafel properties of Sn40Pb and SnCu system solders based on the electrochemical theory. The experimental polarization curves were measured in distilled ionized water and 1 mole $3.5 wt\%$ NaCl electrolyte of $40^{\circ}C$, pH 7.5. Ag/AgCl and graphite were utilized by reference and counter electrodes, respectively. To observe the electrochemical reaction, polarization test was conducted from -250mV to +250mV. From the polarization curves composed of anodic and cathodic curves, we obtained Tafel slop, reversible electrode potential(Ecorr) and exchange current density((cow). In these results, we compared the corrosion rate of SnPb and SnCu solders.

• Bulletin of the Korean Chemical Society
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• 제33권4호
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• pp.1123-1127
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• 2012

P-gp (P-glycoprotein) is a member of the ATP binding cassette (ABC) family of transporters. It transports many kinds of anticancer drugs out of the cell. It plays a major role as a cause of multidrug resistance (MDR). MDR function may be a cause of the failure of chemotherapy in cancer and influence pharmacokinetic properties of many drugs. Hence classification of candidate drugs as substrates or nonsubstrate of the P-gp is important in drug development. Therefore to identify whether a compound is a P-gp substrate or not, in silico method is promising. Recursive Partitioning (RP) method was explored for prediction of P-gp substrate. A set of 261 compounds, including 146 substrates and 115 nonsubstrates of P-gp, was used to training and validation. Using molecular descriptors that we can interpret their own meaning, we have established two models for prediction of P-gp substrates. In the first model, we chose only 6 descriptors which have simple physical meaning. In the training set, the overall predictability of our model is 78.95%. In case of test set, overall predictability is 69.23%. Second model with 2D and 3D descriptors shows a little better predictability (overall predictability of training set is 79.29%, test set is 79.37%), the second model with 2D and 3D descriptors shows better discriminating power than first model with only 2D descriptors. This approach will be used to reduce the number of compounds required to be run in the P-gp efflux assay.

• 정보화연구
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• 제9권4호
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• pp.443-453
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• 2012

다양한 분야의 시스템들은 시스템 오류에 인한 피해의 최소화를 목적으로 안전필수 특성을 가지도록 요구된다. 본 논문에서, 안전필수 시스템으로 많이 연구되는 사이버물리시스템이 그 특성을 가지기위해 고려해야하는 이슈와 주요 요소인 시간을 기반으로 모델 지향 아키텍처에 대하여 논의한다. 메타모델링 접근 방식으로 마감시간, 전환상태와 기준치에 연결하여 시간 기반 아키텍처를 제시하고, 이를 모델지향 아키텍처를 이용하여 설계한다. 메타모델로부터 생성된 안전처리 모델과 함께 오류처리 컴포넌트를 사용하여 사이버 물리 시스템 및 시간기반 도메인에 적용 가능한 안전필수 아키텍처를 제시한다. 그리고 안전필수 시스템 설계 시 기본적 안전처리 상태, 다중적 상태, 복합적 상태를 통하여 세부적인 모델과 그 사례를 나타내었다.

• Journal of Korean Medical Science
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• 제33권51호
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• pp.324.1-324.6
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• 2018

Oxysterol $7{\alpha}$-hydroxylase deficiency is a very rare liver disease categorized as inborn errors of bile acid synthesis, caused by CYP7B1 mutations. As it may cause rapid progression to end-stage liver disease even in early infancy, a high index of suspicion is required to prevent fatal outcomes. We describe the case of a 3-month-old boy with progressive cholestatic hepatitis and severe hepatic fibrosis. After excluding other etiologies for his early liver failure, we found that he had profuse urinary excretion of $3{\beta}$-monohydroxy-${\Delta}^5$-bile acid derivatives by gas chromatography/mass spectrometry analysis with dried urine spots on filter paper. He was confirmed to have a compound heterozygous mutation (p.Arg388Ter and p.Tyr469IlefsX5) of the CYP7B1 gene. After undergoing liver transplantation (LT) from his mother at 4 months of age, his deteriorated liver function completely normalized, and he had normal growth and development until the current follow-up at 33 months of age. We report the first Korean case of oxysterol $7{\alpha}$-hydroxylase deficiency in the youngest infant reported to undergo successful living donor LT to date.

• 유기물자원화
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• 제19권4호
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• pp.60-65
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• 2011

실록산은 유기규소화합물로서 혐기성소화조에서 생산되는 바이오가스로 휘발되며, 이러한 실록산은 바이오가스로 이용되는 가스 연소 엔진 고장의 원인이 된다. 따라서, 바이오가스 내의 실록산을 저감시킬 수 있는 방안이 필요하며 우선적으로 실록산의 발생특성에 대한 조사가 필요하다. 이에 본 연구는 음식물류폐기물폐수의 혐기성소화조에서 발생되는 바이오가스에 함유되어 있는 실록산의 농도 특성을 조사하였다. 총 실록산의 농도는 평균적으로 $9.5mg\;siloxane/m^3$로 나타났으며, 고리 구조 D4의 실록산 농도는 $4.0mg\;siloxane/m^3$로 가장 높게 나타났다. 고리구조 및 선형구조 실록산의 농도는 각각 D4>D5>D6 및 L4>L3>L5>L2의 순서로 나타났다. 1월 2월 및 3월의 실록산 농도 측정 결과에서 1월의 총 실록산 농도가 가장 낮게 나타났으며, 3월의 총 실록산 농도가 가장 높게 나타났다.

• 대한치과보철학회지
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• 제45권2호
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• pp.169-181
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• 2007

Statement of problem: Titanium is well known as a proper metal for the dental restorations, because it has an excellent biocompatibility, resistance to corrosion, and mechanical property. However, adhesion between titanium and dental porcelains is related to the diffusion of oxygen to the reaction layers formed on cast-titanium surfaces during porcelain firing and those oxidized layers make the adhesion difficult to be formed. Many studies using mechanical, chemical and physical methods to enhance the titanium-ceramic adhesion have been actively performed. Purpose: This study meant to comparatively analyse the adhesion characteristics depending on different titanium surface coatings after coating the casts and wrought titanium surfaces with Au and TiN. Material and method: In this study, the titanium specimens (CP-Ti, Grade 2, Kobe still Co. Japan) were categorized into cast and wrought titanium. The wrought titanium was cast by using the MgO-based investment(Selevest CB, Selec). The cast and wrought titanium were treated with Au coating($ParaOne^{(R)}$., Gold Ion Sputter, Model PS-1200) and TiN coating(ATEC system, Korea) and the ultra low fusing dental porcelain was fused and fired onto the samples. Biaxial flection test was done on the fired samples and the porcelain was separated. The adhesion characteristics of porcelain and titanium after firing and the specimen surfaces before and after the porcelain fracture test were observed with SEM. The atomic percent of Si on all sample surfaces was comparatively analysed by EDS. In addition, the constituents of specimen surface layers after the porcelain fracture and the formed compound were evaluated by X-ray diffraction diagnosis. Result: The results of this study were obtained as follows : 1. The surface characteristics of cast and wrought titanium after surface treatment(Au, TiN, $Al_2O_3$ sandblasting) were similar and each cast and wrought titanium showed similar bonding characteristics. 2. Before and after the biaxial flection test, the highest atomic weight change of Si component was found in $Al_2O_3$ sandblasted wrought titanium(28.6at.% $\rightarrow$ 8.3at.%). On the other hand, the least change was seen in Au-Pd-In alloy(24.5at.% $\rightarrow$ 9.1at.%). 3. Much amount of Si components was uniformly distributed in Au and TiN coated titanium, but less amount of Si's was unevenly dispersed on Al2O3 sandblasting surfaces. 4. In X-ray diffraction diagnosis after porcelain debonding, we could see $Au_2Ti$ compound and TiN coating layers on Au and TiN coated surfaces and $TiO_2$, typical oxide of titanium, on all titanium surfaces. 5. Debonding of porcelain on cast and wrought titanium surface after the biaxial flection is considered as a result of adhesion deterioration between coating layers and titanium surfaces. We found that there are both adhesive failure and cohesive failure at the same time. Conclusion: These results showed that the titanium-ceramic adhesion could be improved by coating cast and wrought titanium surfaces with Au and TiN when making porcelain fused to metal crowns. In order to use porcelain fused to titanium clinically, it is considered that coating technique to enhance the bonding strength between coating kKlayers and titanium surfaces should be developed first.

• 한국식품영양과학회지
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• 제38권2호
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• pp.211-216
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• 2009

일반적으로 폐기 처분하거나 비료로 재활용하는 한약을 추출하고 남는 한약박을 발효하여 영양분으로 첨가하는 팰릿 대신 폐면과 섞어 균상배지로 사용하여 느타리버섯을 재배할 때 수확량과 저장성에 대한 연구를 하였다. 또한, 한약박은 불특정 한약재들이 섞여 있으므로 이로 인해 문제가 나타날 수도 있으므로 한약박의 성분이 느타리버섯으로 전이되는지 여부를 조사하였다. 한약박 70%나 100%에서 느타리버섯을 재배할 때 질병이 생겨 고사되는 버섯의 수도 적었고, 성장속도도 빨라서 수확량도 많았다. 폐면과 펠릿을 이용한 대조군과 한약박을 배지에서 재배한 처리군들의 HPLC chromatogram에 차이를 전혀 나타내지 않았고 지표물질로 사용한 glycyrrhizin이 전혀 검출되지 않았다. 즉, 한약박의 성분 자체가 그대로 전이되지는 않았고, 한약박에 함유된 성분을 영양소로 이용하여 버섯의 품질을 향상시켰다. 한약박을 70%나 100%를 사용한 배지에서 재배된 느타리버섯의 저장성이 향상되어 저장기간 동안 중량 감소가 가장 적었고, 갓과 자루의 경도의 저하도 가장 적었다. 그러나 외관의 품질을 나타내 주는 색도의 변화는 배지 종류에 영향이 적었다. 결론적으로 한약박을 70% 이상을 배지로 사용하였을 때 한약성분의 직접적인 전이는 없어서 버섯의 상품성을 저하시키지 않았으며 성장률이 빠르며 수확률도 많았고, 조직이 치밀하여 저장성도 향상시켰다. 그러므로 한약박을 느타리버섯뿐만 아니라 여러 종류의 버섯 재배에 활용하는 것이 필요하겠다.

• 한국해안·해양공학회논문집
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• 제27권4호
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• pp.246-257
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• 2015

피해 자료의 부족에 따른 불확실성 뿐만 아니라 시간의 진행에 따른 불확실성을 고려하기 위하여 추계학적 확률과정을 이용하여 시간에 따른 구조물의 피해 경로를 정량적으로 추적하였다. 누적피해도와 내구년수의 분포함수를 시간의 함수로 산정하여 추계학적 확률과정을 적용할 때 주의해야 하는 중요한 특성들을 제시하였다. 특히, 본 연구에서는 추계학적 확률과정을 경사제 피복재에 적용하여 시간에 따른 누적 피해도를 추적할 수 있는 방법을 제안하였다. 확률과정의 매개변수들을 추정하기 위하여 개발된 표본경로기법을 이용하여 경사제 피복재의 시간에 따른 누적 피해도가 포화거동을 따른다는 사실이 확인되었다. 또한 누적 피해도 산정시 중요한 역할을 하는 멱함수의 지수를 정량적으로 산정하여 경사제 피복재의 누적 피해도를 시간에 따라 추적하는 것이 가능했다. 마지막으로 한계수준을 다양하게 변화시키면서 파괴확률의 거동특성을 해석하였다.

• 대한방사선치료학회지
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• 제8권1호
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• pp.41-54
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• 1996

The secondary electrons developed by interaction between primary beam and a tray mounted for blocks in Megavoltage irradiation result in excess soft radiation dose to the surface layer. To reduce this electron contamination, electron filters have been used to be attached under a tray. Various filters with Cu and Al plates in six different thickness and Cu/Al combined plates in 3 different thickness were tested to measure the reduction rate of secondary electron contamination to the surface layer. The measurement to find optimal filter was performed on 6MV linear accelerator in $10 cm{\times}10 cm$ field size and fixed 78.5cm source to measurement points distance from surface to maximum build up point in 2mm intervals. The result was analyzed as the ratio of measured doses with using filters, to standard doses of measured open beam. The result of this study was fellowing : 1. The contaminated low energy radiation were mainly produced by blocking tray. 2. The surface absorbed dose was slowly increased by increasing irradiation field size but rapidly increased at field size above $15cm{\times}15cm$. 3. Al plate upto 2.5mm thickness used as a filter was found to be inadequate due to the failure of reduction of the surface absorbed dose below doses of the under surface upto the maximal build up. Cu 0.5mm plate and Cu 0.28mm/A1 1.5mm compound plate were found to be optimal filters. 4. By using these 2 filters, the absorbed dose to the surface were effectively reduced $5.5\%$ in field size $4cm{\times}4cm,\;11.3\%$ in field size $10cm{\times}10cm,\;22.3\%$ in field size $25cm{\times}25cm$. 5. In field size $10cm{\times}10cm$, the absorbed dose to the surface of irradiation was reduced by setting TSD 20cm at least,. but effective and enough dose reduction could be achieved by setting TSD 30cm as 2 optimal filters used. 6. More surface dose absorbed at TSD less than 7.4cm with a tray and filters together indicated that soft radiation was also developed by filters. 7. The variation of PDD by the different size of irradiation field was minimal as 2 optimal filters used. There was also not different in variation of PDD according to using any of two different filters. 8. PDD was not effected either by various TSD or by using the different filter among two.