• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제26권6호
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• pp.581-590
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• 2000

Alterations in the cellular genome affecting the expression or function of genes controlling cell growth and differentiation are considered to be the main cause of cancer. Over 30 oncogenes can be activated by insertional mutagenesis, single point mutations, chromosomal translocations and gene amplification. The ras oncogenes have been detected in $15{\sim}20%$ of human tumors that include some of the most common forms of human neoplasia and are known to acquire their transforming properties by single point mutations in two domains of their coding sequences, most commonly in codons 12 and 61. The ras gene family consists of three functional genes, N-ras, K-ras and H-ras which encode highly similar proteins of 188 or 189 amino acid residues generically known as P21. ras proteins have been shown to bind GTP and GTP, and possess intrinsic GTPase activity. Experimental study was performed to observe the mutational change of the ras gene family and apply the results to the clinical activity. 36 Golden Syrian Hamster each weighing $60{\sim}80g$ were used and painted with 0.5% DMBA by 3 times weekly on the right buccal cheek(experimental side) for 6, 8, 10, 12, 14 and 16 weeks. Left buccal cheek (control side) was treated with mineral oil as the same manner of the right side. The hamsters were sacrificed on the 6, 8, 10, 12, 14 & 16 weeks. Normal and tumor tissues from paraffin block were completely dissected by microdissection and DNA from both tissue were isolated by proteinase K/phenol/chloroform extraction. Segments of the K-ras and H-ras gene were amplified by PCR using the oligonucleotide primers corresponding to the homologous region (codon 12 and 61) of the hamster gene, and then confirmational change of ras genes was observed by SSCP and autosequencing analysis. The results were as follows : 1. Malignant lesion could be found in the experimental side from the experimental six weeks. 2. One hamster among six showed point mutation of the H-ras codon 12($G{\rightarrow}A$ transition) at the experimental 10 and 14 weeks. 3. One of six at 6 weeks, two of six at 8 weeks and one of six at 12 weeks revealed the confirmational change of the H-ras codon 61($A{\rightarrow}T$ transversion). 4. The incidence of point mutation of H-ras codon 12 and 61 were 5.5%(2 of 36) and 11%(4 of 36) respectively. 5. Point mutation of the K-ras could not be seen during the whole experimental period. Form the above results, these findings strongly support the concept that H-ras oncogenes may have the influence of the DMBA induced carcinoma of hamster buccal pouch.

• 융합보안논문지
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• 제15권2호
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• pp.69-80
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• 2015

본 연구는 북한의 보훈정책의 분석을 통하여 통일이후 남북한 보훈제도 통합의 기틀을 마련하는데 그 목적을 두고 연구하였다. 먼저 북한의 보훈법체계와 보훈제도 전개과정을 고찰한 후 통일기반 구축 및 통일대비 북한 보훈정책의 시사점을 분석해 보았다. 북한의 보훈정책을 체제수립 당시부터 현재까지 고찰하였다. 고찰 결과를 바탕으로 통일대비 보훈정책 이념 재정립 문제와 보훈정책 통합방안에 대하여 이념적인 사항과 제도적인 통합방안을 제시하였다. 이와 같은 연구결과는 통일 후 통합된 국가보훈정책을 어떠한 방향으로 추진하여야 될 것인지 조그마한 지표가 될 수 있을 것이다. 통일 이후에도 상당부분 남북한 구성원들 간에는 다양한 차이와 갈등의 요인을 내포하면서 국민통합으로 진행하는데 있어서 갈등 요인이 노출될 것이다. 철저한 준비와 사회적 공감대 형성이 무엇보다도 중요하다. 국가 보훈정책도 기본으로 돌아가서 재점검하고 통합의 준비를 하여 할 시기이다. 북한의 보훈제도는 시기를 달리하면서 북한체제의 근간이며 발전의 원동력으로 활용하고 있다는 사실을 알 수 있다. 보훈정책의 재이념은 통일국가와 국민정체성의 상징이며 나아가 사회통합정신의 상징성을 나타내어야 할 것이다. 아울러서 나라사랑의 정신과 국가안보의식이 반드시 내포되어야 할 것이다. 또한 통일을 대비하는 보훈정책의 통합은 남북 공히 공통의 역사 인식을 공유하는 것이 중요한 사항이며, 이러한 바탕위에서 보훈정책의 통합을 실시하여야 할 것이다.

• Journal of Periodontal and Implant Science
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• 제50권2호
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• pp.106-120
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• 2020

Purpose: A new form of porous polyethylene, characterized by higher porosity and pore interconnectivity, was developed for use as a tissue-integrated implant. This study evaluated the effectiveness of porous polyethylene blocks used as an onlay bone graft in rabbit mandible in terms of tissue reaction, bone ingrowth, fibrovascularization, and graft-bone interfacial integrity. Methods: Twelve New Zealand white rabbits were randomized into 3 treatment groups according to the study period (4, 12, or 24 weeks). Cylindrical specimens measuring 5 mm in diameter and 4.5 mm in thickness were placed directly on the body of the mandible without bone bed decortication, fixed in place with a titanium screw, and covered with a collagen membrane. Histologic and histomorphometric analyses were done using hematoxylin and eosin-stained bone slices. Interfacial shear strength was tested to quantify graft-bone interfacial integrity. Results: The porous polyethylene graft was observed to integrate with the mandibular bone and exhibited tissue-bridge connections. At all postoperative time points, it was noted that the host tissues had grown deep into the pores of the porous polyethylene in the direction from the interface to the center of the graft. Both fibrovascular tissue and bone were found within the pores, but most bone ingrowth was observed at the graft-mandibular bone interface. Bone ingrowth depth and interfacial shear strength were in the range of 2.76-3.89 mm and 1.11-1.43 MPa, respectively. No significant differences among post-implantation time points were found for tissue ingrowth percentage and interfacial shear strength (P>0.05). Conclusions: Within the limits of the study, the present study revealed that the new porous polyethylene did not provoke any adverse systemic reactions. The material promoted fibrovascularization and displayed osteoconductive and osteogenic properties within and outside the contact interface. Stable interfacial integration between the graft and bone also took place.

• 한국전자파학회논문지
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• 제23권6호
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• pp.691-699
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• 2012

본 논문에서는 유전체 공진기와 마이크로스트립 라인 간의 결합 구조를 개선시켜 저위상 잡음을 갖는 전압제어 유전체 공진기 발진기(Vt-DRO: Voltage-tuned Dielectric Resonator Oscillator)를 설계, 제작하였다. 설계된 발진기는 유전체 공진기, 위상천이기, 증폭기로 구성된다. 발진기의 위상 잡음은 공진기의 군지연과 밀접하게 관계되며, 이러한 관계를 수식적으로 도출하고, 이를 예측하는 방법을 제안하였다. 유전체 공진기와 마이크로스트립 라인간의 결합 구조를 조정하여 약 53 nsec의 높은 군지연을 갖도록 설계하였다. 각 부의 측정은 측정의 편의성을 위해 웨이퍼 프로브를 이용하였으며, 이를 위하여 각 부의 입출력 포트를 CPW(Coplanar Waveguide)로 설계하였다. 각 부를 연결하여 측정한 S-파라미터는 개루프 발진 조건을 만족하였다. 설계된 개루프의 입출력을 연결하고 폐루프로 구성하여 전압 제어 유전체 공진기 발진기를 구현하였다. 측정 결과, 5.3 GHz의 발진 주파수에서 위상 잡음은 수식으로부터 도출한 값과 근사한, 100 kHz offset 주파수에서 -132.7 dBc/Hz를 얻었다. 이때 출력 전력은 약 4.5 dBm, 전기적 주파수 조정 범위는 0~10 V의 조정 전압에서 약 5 MHz를 보였다. PFTN-FOM(Power Frequency Tuning Normalized Figure of Merit)은 약 -31 dB를 보였다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.36-36
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• 2017

Out of twenty common protein amino acids, there are many kinds of non protein amino acids (NPAAs) that exist as secondary metabolites and exert ecological functions in plants. Mimosine (Mim), one of those NPAAs derived from L. leucocephala acts as an iron chelator and reversely block mammalian cell cycle at G1/S phases. Cysteine (Cys) is decisive for protein and glutathione that acts as an indispensable sulfur grantor for methionine and many other sulfur-containing secondary products. Cys biosynthesis includes consecutive two steps using two enzymes-serine acetyl transferase (SAT) and O-acetylserine (thiol)lyase (OASTL) and appeared in plant cytosol, chloroplast, and mitochondria. In the first step, the acetylation of the ${\beta}$-hydroxyl of L-serine by acetyl-CoA in the existence of SAT and finally, OASTL triggers ${\alpha}$, ${\beta}$-elimination of acetate from OAS and bind $H_2S$ to catalyze the synthesis of Cys. Mimosine synthase, one of the isozymes of the OASTLs, is able to synthesize Mim with 3-hydroxy-4-pyridone (3H4P) instead of $H_2S$ for Cys in the last step. Thus, the aim of this study was to clone and characterize the cytosolic (Cy) OASTL gene from L. leucocephala, express the recombinant OASTL in Escherichia coli, purify it, do enzyme kinetic analysis, perform docking dynamics simulation analysis between the receptor and the ligands and compare its performance between Cys and Mim synthesis. Cy-OASTL was obtained through both directional degenerate primers corresponding to conserved amino acid region among plant Cys synthase family and the purified protein was 34.3KDa. After cleaving the GST-tag, Cy-OASTL was observed to form mimosine with 3H4P and OAS. The optimum Cys and Mim reaction pH and temperature were 7.5 and $40^{\circ}C$, and 8.0 and $35^{\circ}C$ respectively. Michaelis constant (Km) values of OAS from Cys were higher than the OAS from Mim. Inter fragment interaction energy (IFIE) of substrate OAS-Cy-OASTL complex model showed that Lys, Thr81, Thr77 and Gln150 demonstrated higher attraction force for Cys but 3H4P-mimosine synthase-OAS intermediate complex showed that Gly230, Tyr227, Ala231, Gly228 and Gly232 might provide higher attraction energy for the Mim. It may be concluded that Cy-OASTL demonstrates a dual role in biosynthesis both Cys and Mim and extending the knowledge on the biochemical regulatory mechanism of mimosine and cysteine.

• Asian-Australasian Journal of Animal Sciences
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• 제19권1호
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• pp.55-60
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• 2006

This experiment was conducted to investigate the effects of selenium (Se) sources and levels on growth performance, nutrient digestibility and Se retention in growing-finishing pigs. A total of 56 crossbred pigs ([$Landrace{\times}Yorkshire$]${\times}$Large White) with average $28.5{\pm}0.2kg$ BW were allotted to 7 treatments on the basis of sex and weight in two replicates and four pigs per pen. A $2{\times}3$ factorial arrangement of treatments was used in a randomized complete block (RCB) design. Two sources of Se (selenite Se or Se-enriched yeast) were added at 0.1, 0.3 and 0.5 mg/kg to each treatment diet. A basal diet without Se supplementation was the seventh treatment group. Three pigs per treatment were randomly selected and samples of loin, liver, pancreas and a kidney were collected, frozen and later analyzed for Se. The digestibility trial was conducted to evaluate the apparent absorption and retention of Se and availability of other nutrients. Growth performance was not affected by dietary sources and levels of Se. No growth retardation was observed in the 0.5 mg/kg dietary Se treatment group regardless of Se sources. The Se concentration of serum in Se supplemented groups was increased compared with the control group (p<0.01). During the growing and finishing phase, Se in serum was clearly increased when organic Se was provided (p<0.01). Interaction of Se source ${\times}$ Se level was observed in Se concentration of loin, liver and pancreas of the pigs at the end of experiment. Selenium retention in the liver, kidney, pancreas and loin of pigs was increased as dietary Se level increased and was higher when pigs were fed organic Se resulting in an interaction response (p<0.01). Nutrient digestibilities were not affected by dietary Se sources or levels. No dietary Se source ${\times}$ Se level interaction was observed in nutrient digestibility. The results from this experiment indicated that dietary Se sources and levels affected the distribution of Se in the body of growing-finishing pigs. Organic source of Se, such as Se-enriched yeast resulted in higher serum and tissue Se concentration compared to inorganic form, while no beneficial effects on nutrient digestibility were observed from dietary Se supplementation in growing-finishing pigs.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제37권5호
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• pp.415-420
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• 2011

Purpose: Calcium phosphate cement (CPC) is one of many useful materials for restoring tooth defects, periodontium and maxillofacial area. Chitosan is a biodegradable material that has been shown to promote the growth and differentiation of osteoblasts in culture. This study examined the interaction between odontoblasts and bio-calcium phosphate cement reinforced with chitosan. Materials and Methods: $5{\times}10^3$ odontoblastic cells were seeded into each well. Various concentrations of bio-calcium phosphate cement reinforced with chitosan (10, 20, 50, 100, 200, 500 ${\mu}g$/ml, 1, 2, 4 mg/ml) were diluted and added to the wells. The well was incubated for 24 h, 48 h and 72 h. After incubation, the number of cells was assessed to determine the cell viability. A cytokinesis-block micronucleus assay and chromosomal aberration test were carried out to estimate the extent of chromosomal abnormalities. Microscopic photographs and RT-PCR were performed to examine the adhesion potential of bio-calcium phosphate cement reinforced with chitosan. Results: Bio-CPC-reinforced chitosan did not show significant cytotoxicity. The number of damaged chromosomes in the cells treated with Bio-CPC-reinforced chitosan was similar to that in the control cells. There was no significant increase in the number of chromosomal aberrations in the Bio-CPC reinforced chitosan exposed cells. Microscopic photographs and RT-PCR confirmed the adhesive potential of bio-CPC reinforced chitosan to odontoblasts. Conclusion: Bio-CPC-reinforced chitosan did not affect the odontoblastic cell viability, and had no significant cytotoxic effect. Bio-CPC-reinforced chitosan showed adhesive potential to odontoblasts. These results are expected form the basis of future studies on the effectiveness of dental restorative materials in Bio-CPC reinforced with chitosan.

• Asian-Australasian Journal of Animal Sciences
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• 제18권4호
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• pp.502-511
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• 2005

The effects of different levels of crude protein (CP) and cottonseed meal replacing for soybean meal in cassava chips and rice straw-based diets for mid-lactating cows (100-150 day in milk [DIM]), were studied using 32 multiparous Holstein Fresian crossbred dairy cows. Diets containing 10.5, 12.5, 13.7, 14.4% CP of the rations and 0, 12.1, 14.9, 17.8% cottonseed meal were fed to cows for 60 days. Thirty two cows were randomly divided into four dietary treatments using a Randomized complete block design. Four dietary treatments were offered in the form of total mixed ration (TMR) with concentrate to roughage (chopped rice straw) at 60:40 and offered ad libitum. Dry matter (DM) and neutral detergent fiber (NDF) intakes tended to linearly increase with increasing dietary CP levels. Intakes and digestibility of crude protein increased linearly with increasing dietary CP level (p<0.01). Crude protein digestibility of the 10.5% CP diet was lower (p<0.05) than that in diets with higher levels of CP, while there were no significant differences among the other three levels of CP (12.5, 13.7 and 14.4%). Daily milk yield tended to increase with increased CP from 10.5 to 14.4%. Income over feed in terms of US$/kg of milk increased with increased CP from 10.5 to 13.7% and decreased when the CP level was higher than 13.7% (quadratic effect p<0.09). Milk composition was not significantly affected by increasing level of CP, however there were relatively high contents of protein and fat among treatments. The proportion of milk-urea N (MUN), ammonia-N ($NH_3$-N) and bloodurea N (BUN) were closely correlated and increased linearly with increasing CP levels (p<0.01). Balanced diet was found in diet containing 12.5 and 13.7% CP of the rations when BUN and MUN were used as indicators of the protein to energy ratio in the diet. Conclusions can be made that increasing dietary CP levels from 10.5 to 13.7% using cottonseed meal as the main source to completely replace soybean meal was beneficial to cows consuming rice straw and cassava chips based-diets. Increasing the CP level above 13.7% of total ration did not additionally improve milk yield and composition or net income.

• 터널과지하공간
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• 제14권3호
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• pp.167-174
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• 2004

본보는 2003년도에 국제 학술지에 수록된 논문을 국내의 전문가들에게 소개하는 기술보고서이다. 본 연구에서 취성파괴를 보이는 암석에 대하여 시간의존성의 중요성을 설명하는 파괴역학적 모텔이 개발되었다. 균열면을 따라 형성된 신선한 구간인 암석 브리지의 파괴규명으로 불연속면의 점착강도가 감소하는 모델이 설정 되었다. 특히 임계조건 이전에 발생하는 균열성장을 사용하여 파괴역학적 모델을 개발하였는데, 이로부터 시간과 점착강도의 관계를 독립된 수식으로 표현하였다. 예로서 평면파괴가 예상되는 암석 블록에 대한 분석이 이루어 졌다. 절리면의 점착강도는 연속적으로 감소하는 것으로 밝혀줬는데, 초기에는 아주 점진적이며 그 후에는 급격하다. 그러다가 어느 시점에서는 감소된 점착강도는 사면의 불안정과 붕괴를 야기한다. 두 번째 예에서는 몇몇 물질 상수들이 분산을 가진다고 가정하였다. 여기에서는 확률론적으로 사면의 안정성이 분석되었는데 사면의 파괴확률을 시간의 함수로 예견할 수 있다. 시간이 경과함에 따라 사면의 파괴확률은 점점 증가하여 초기에 5% 수준에서 100년 후에는 40% 이상으로 증가한다. 이러한 예제들은 지하구조물이 비록 비교적 단기목적이라 하더라도 불연속면을 갖는 암반의 시간의존성 거동을 예측할 수 있음을 보여 주었다.

• 한국정보과학회논문지:시스템및이론
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• 제33권8호
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• pp.536-546
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• 2006

회화적 애니메이션은 비디오 동영상을 이용하여 손으로 그린 듯 한 회화적 느낌을 표현하는 방법이며 프레임 간 브러시 스트로크의 시간적 일관성을 유지하는 것이 가장 중요한 요소이다. 본 논문에서는 프레임 간 브러시 스트로크의 일관성을 유지하기 위한 모션 맵 생성을 제안한다. 모션 맵이란 모션이 발생한 에지 위치를 기준으로 해서 모션 정보를 더함으로써 프레임 간 에지가 움직이는 영역을 말한다. 본 논문에서 사용한 모션 추정 방법은 광류 (optical flow) 방법과 블록 기반 방법을 이용하였으며 여러 가지 모션 추정 방법을 통해서 얻은 모션 정보 ( 방향과 크기 ) 중 신호 대 잡음비 (PSNR)가 가장 큰 방법을 최종 모션 정보로 선택하여 모션 맵을 생성하였다. 생성된 모션 맵은 다음 프레임의 덧칠 부분을 결정해 준다. 손으로 그린 듯 한 회화적 느낌을 표현하면서도 프레임 간 브러시 스트로크의 시간적 일관성을 유지하기 위해서 브러시 스트로크의 방향을 결정해주는 강한 에지에 대해서만 모션 정보를 적용하였다. 또한 다중노출기법과 소스 영상과 캔버스간의 차이 맵을 이용하여 프레임 간 플릭커링 현상을 줄이고자 하였다. 구조적 일관성을 유지하기 위해 국부 기울기 보간법 (local gradient interpolation)을 이용하여 브러시 스트로크 간 방향의 일관성을 유지하였다.