• 융복합기술연구소 논문집
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• 제7권2호
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• pp.13-16
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• 2017

The design of sealing mechanisms of a manual pressure valve was analyzed with FE analysis for a hydrogen fuels charge and discharge system of FCEV. The damage prediction of the O-ring with respect to the material models of rubbers was calculated by the gap analysis of the backup ring and O-ring according to the internal pressure. Two kinds of the rubber material characteristic models were adopted to the O-ring. One was the linear elastic and the other was hyperelastic of Ogden $3^{rd}$ order model. The experimental data of urethane of Shore hardness 90 was utilized to the curve fitting of hyperelastic properties. It was found that the contact pattern of the backup ring was different in two models and the sealing mechanism was better in the case of the hyperelastic characteristic model.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(5)
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• pp.293-296
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• 2002

In this study, the object is a development on uroflowmetry system to detect a voiding symptom conveniently in home or hospital. The hardware was composed of mechanism and system circuit part, the software was divided into firmware and PC program part. The following experiment was performed to evaluate an ability of classification and fitness. First, the following parameters was calculated in each flow curve pattern. The parameters are MFR, AFR, VOL, VT, FT, and TMF. A significant difference among parameters was examined through a statistical analysis for extracted parameters between normal and abnormal group. In the next work, the following experimentation was performed to classify the voiding symptom. Analysis of congregate rate was examined to find out classification possibility about each symptom of BPH, voiding difficulty, detrusor failure and hyperreflexia, unstable bladder. The uroflow data with the above symptom was divided into normal and abnormal group using fuzzy classifier. and that was performed appending the other group again. Fuzzy classification result using MFR and AFR was superior by 89.6 % more than grouping evaluation including VOL.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제30권4호
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• pp.333-344
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• 2008

The objectives of this study was to explore the growth pattern of the oral squamous cell carcinoma when overexpressed COX was inhibited, explore the pathway that COX inhibitors suppressed the proliferation of cancer cells, and then hereafter investigate the potential of COX as chemopreventive target for oral squamous cell carcinoma. For confirming the COX-dependent effect and mechanisms on growth of the oral cancer cells, we treated the nonselective NSAID, Mefenamic acid and COX-2 selective inhibitor, Celecoxib in HN4 cell line. And then the cell line was evaluated with MTT assay and growth curve, the production of PGE2, total RNA extraction and RT-PCR analysis, and TEM The results were obtained as follows: 1. After administration of medication, in the result of MTT assay, Celecoxib inoculated group inhibit the cell growth rather than Mefenamic acid inoculated group. 2. The growth curve of cell line showed as time passes by there was a dramatic cell growth in the control group, and gradual growth inhibition was found in medication inoculated group and, in Celecoxib inoculated group there was more inhibition of cell growth. 3. After the administration of medication, Celecoxib tend to inhibit the synthesis of PGE2 more than Mefenamic acid. Mefenamic acid inhibit the synthesis of PGE2 more as the concentration gets high, but Celecoxib inhibited the synthesis of PGE2 even in low concentration. 4. After the administration of medication, the revelation of COX mRNA in cell line, there was a 50% decrease in COX-1, 60% decrease in COX-2 as in $50{\mu}M$ Mefenamic acid, and in Celecoxib $50{\mu}M$ there was not much difference in COX-1 and 90% decrease in COX-2 was found. 5. HN4 cell line showed broken nucleus and tangled cytoskeleton bundles in cytoplasm which meant apoptotic features after the treatment of Celecoxib in TEM view. Depending on the above results, we estimate that the inhibition of the expression of COX-2 cause the growth suppression of the oral squamous cell carcinoma, and it get achieved through pathway of reduced PGE2 production and increased apoptosis. In addition to, because COX-2 selective inhibitor specifically act to COX-2, it is considered that COX-2 selective inhibitor has the adequate potential as chemopreventive agent for oral squamous cell carcinoma.

• 대한임상검사과학회지
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• 제38권3호
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• pp.166-172
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• 2006

Metallo-${\beta}$-lactamase (MBL) can hydrolyze all ${\beta}$-lactams except monobactams and frequently coexists with various antibiotic resistance genes such as aminoglycoside resistance, sulfonamide resistance gene, etc. Therefore, the effective antibiotics against infections by these bacteria are markedly limited or can't even be found. We tried to search in-vitro antimicrobial combinations with synergistic effects for a VIM-2 type MBL producing Pseudomonas aeruginosa, isolated from clinical specimen. On the selection of antibiotic combinations with synergistic effects, we performed a one disk synergy test, modified Pestel's method, in agar without aztreonam (AZT). The bacteriostatic synergistic effects of this tests were scored as $S_1$ (by susceptibility pattern in agar without antibiotics), $S_2$ (by the change of susceptibility in agar with or without antibiotics) and $S_3$ ($S_1$ + $S_2$) and was classified into weak (1 point), moderate (2 points) and strong (3 points) by $S_3$ score. Subsequently, we carried out the time-killing curve for the antibiotic combinations with the strong synergistic bacteriostatic effect. One VIM-2 type MBL producing P. aeruginosa confirmed by the PCR showed all resistance against all ${\beta}$-lactams except AZT, aminoglycoside and ciprofloxacin. In the one disk synergy test, this isolate showed a strong bacteriostatic synergistic effect for the antibiotic combination of AZT and piperacillin-tazobactam (PIP-TZP) or AZT and amikacin (AN). On the time-killing curve after six hours of incubation, the colony forming units (CFUs/mL) of this bacteria in the medium broth with both combination antibiotics were decreased to 1/18.7, 1/17.1 of the least CFUs of each single antibiotics. The triple antibiotic combination therapy including AZT, PIP-TZP and AN was shown to be significantly synergistic after 8 hrs of exposure. In a VIM-2 MBL producing P. aeruginosa with susceptibility for AZT, the triple antibiotic combination therapy including AZT, PIP-TZP and AN may be considered as an alternative antibiotics modality against the infection by some MBL type. But the antimicrobial combination therapy for many more MBL producing isolates is essential to know as soon as possible for the selection of effective treatment against the infection by this bacteria.

• 한국지하수토양환경학회지:지하수토양환경
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• 제12권4호
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• pp.54-59
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• 2007

본 연구에서는 수학적 모델링을 통해 강우에 기인하는 지하수위 변동예측 준-해석학적 모델을 개발하였다. 개발된 모델은 홍천 지역의 지하수위 변동을 예측에 적용되었으며 이를 위하여 지하수 변동 관측자료 및 강우자료가 이용되었다. 개발된 모델은 비선형 파라미터 예측 코드를 활용하여 2003년 지하수위 변동을 예측하도록 적정되었으며 이렇게 최적화에 이용된 입력 파라미터는 그 다음해인 2004년 지하수위 변동을 예측하는데 활용되었다. 강우자료에 기초한 2004년 지하수위 변동 예측은 RMS 오차가 0.18 m로 관측지하수위의 표준편차가 0.44 m인 것으로 미루어 보았을 때 대체로 양호한 것으로 판단된다. 또한 본 연구에서는 개발된 모델을 이용하여 지표 피복의 변화에 기인하는 함양율 감소 시 발생되는 지하수위 변동 예측 및 양수에 의한 인공적인 지하수위 강하를 모사하는데 적용하였다. 본 연구의 결과는 보다 정확한 지하수위 변동 예측증 위해서는 지하수 함양율을 상수로 적용하는 것이 적절치 않으며 강우 패턴의 함수로 결정되어야 함을 보인다.

• Journal of Crop Science and Biotechnology
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• 제11권1호
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• pp.75-82
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• 2008

Functional stay-green is a beneficial trait that may increase grain yield through the sustained photosynthetic competence during monocarpic senescence in cereal crops. The temporal changes of photosynthesis and related characteristics throughout the grain filling period of a stay-green japonica rice "SNU-SG1" was compared in growth chamber conditions with three high-yielding cultivars(HYVs) and their $F_1$ hybrids with SNU-SG1. SNU-SG1 exhibited a typical characteristic of functional stay-green in terms of chlorophyll degradation and photosynthetic competence during grain filling. According to the photosynthesis-light response curve measured at 10 and 35 d after heading for the flag leaf, SNU-SG1 exhibited higher initial light conversion efficiency and thus higher gross photosynthetic rate at light saturation compared to HYVs. Light saturation point was not different among genotypes, ranging from 1000 to 1500 ${\mu}mol$ photon $m^{-2}s^{-1}$. Net photosynthetic rate at light saturation($P_{max}$) of the upper four leaves in SNU-SG1 was much higher and sustained longer throughout grain-filling than HYVs and $F_1$ hybrids. The sustained high photosynthetic competence of SNU-SG1 during grain filling was ascribed to the longer maintenance of high mesophyll conductance that resulted from not only high chlorophyll content and its delayed degradation but also the slow degeneration of photosystem II(PS II) as judged by chlorophyll fluorescence($F_v/F_m$) of flag leaves. $F_1$ hybrids showed slow degeneration of photosystem II similar to the male parent SNU-SG1 while chlorophyll degradation pattern close to female parents, thus exhibiting a little higher $P_{max}$ than female parents. These results suggest that SNU-SG1 has a typical functional stay-green trait that can be utilized for increasing rice yield potential through the improved dry matter production during grain filling.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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• pp.815-826
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• 2009

The paper presents a case study addressing the design and construction aspects for DCM(Deep Cement Mixing) method employed as the foundation of a caisson type breakwater with heavy weight(10,700 ton/EA) and a high design wave height($H_{1/3}$=8.7m). The DCM was designed for the project(Ulsan New Port North Breakwater Phase 1) by optimizing the pattern of DCM columns with a combination of short and long columns (i.e., block type(upper 3m)+wall type(lower)) and considering overlapped section between columns as a critical section against shear force where the coefficient of effective width of treated column($\alpha$) was estimated with caution. It was shown that the value can be 0.9 under the condition with the overlapped width of 30cm. In addition to that, a field trial test was performed after improving conventional DCM equipment (e.g., mixing blades, cement paste supplying pipes, multi auger motor, etc.) to establish a standardized DCM construction cycle (withdrawal rate of mixing blades) which can provide the prescribed strength. The result of the field strength test for cored DCM specimens shows that the averaged strength is larger than the target strength and the distribution of the strength(with a defect rate of 7%) also satisfies with the quality control normal distribution curve which allows defect rate of 15.9%.

• 대한치과보철학회지
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• 제27권1호
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• pp.55-81
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• 1989

Recently the instantaneous center concept has been to understand the biomechanics by which a tissue derangement causes a mechanical derangement in human joint. Therefore, to understand the biomechanics of temporomandibular joint (T.M.J.) as a part of human joint, it is necessary to clarify the instantaneous center of rotation (I.C.R.) in the mandibular movement. Twenty male subjects without T.M.J. disorder and mandibular deviation during the mandibular movement were selected for this study. The habitual opening and closing paths were recorded on the paper of the sagittal metal plate by two pencil markers connected to the resin open clutch attached on the lower teeth, which was designed for this study. The coordinates of the 33-target points and the 109-anatomical landmarks were obtained using a Summagraphic digitizer connected to a 18AT computer. The original raw data of the opening and closing paths were smoothed by B-spline curve fitting technique and then the I.C.R. pathways were determined mathematically by the computer using algorithm for finding the I.C.R. of a planer rigid body model. Also the opening and closing movements of the mandible were simulated according to the determined I.C.R. The results obtained from this study were as follows. 1. At the early opening and the last closing, I.C.R's were almost distributed around the mastoid process outside the mandibular body without the presence in the region of the mandibular condyle. 2. The I.C.R. pathway showed variable patterns to each subject at the opening and closing movements. 3. The K constant with uniform pattern was obtained by the rotation angle times the radius, which was assumed to the index of the mandibular movement. 4. The opening and closing movements of the mandible were simulated by the I.C.R. pathways at the habitual opening and closing movements. 5. The mandibular condyle was rotated or translated accordng to the relative rotation angle and radius of the determinant factors of K contant.

• Asian Pacific Journal of Cancer Prevention
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• 제13권9호
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• pp.4469-4475
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• 2012

Background: The potential use of hypomethylation of Long INterspersed Element 1 (LINE-1) and Alu elements (Alu) as a biomarker has been comprehensively assessed in several cancers, including head and neck squamous cell carcinoma (HNSCC). Failure to detect occult metastatic head and neck tumors on radical neck lymph node dissection can affect the therapeutic measures taken. Objective: The aim of this study was to investigate the LINE-1 and Alu methylation status and determine whether it can be applied for detection of occult metastatic tumors in HNSCC cases. Methods: We used the Combine Bisulfite Restriction Analysis (COBRA) technique to analyse LINE-1 and Alu methylation status. In addition to the methylation level, LINE-1 and Alu loci were classified based on the methylation statuses of two CpG dinucleotides in each allele as follows: hypermethylation ($^mC^mC$), hypomethylation ($^uC^uC$), and 2 forms of partial methylation ($^mC^uC$ and $^uC^mC$). Sixty-one lymph nodes were divided into 3 groups: 1) non-metastatic head and neck cancer (NM), 2) histologically negative for tumor cells of cases with metastatic head and neck cancer (LN), and 3) histologically positive for tumor cells (LP). Results: Alu methylation change was not significant. However, LINE-1 methylation of both LN and LP was altered, as demonstrated by the lower LINE-1 methylation levels (p<0.001), higher percentage of $^mC^uC$ (p<0.01), lower percentage of $^uC^mC$ (p<0.001) and higher percentage of $^uC^uC$ (p<0.001). Using receiver operating characteristic (ROC) curve analysis, $%^uC^mC$ and $%^mC^uC$ values revealed a high level of AUC at 0.806 and 0.716, respectively, in distinguishing LN from NM. Conclusion: The LINE-1 methylation changes in LN have the same pattern as that in LP. This epigenomic change may be due to the presence of occult metastatic tumor in LN cases.

• 암석학회지
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• 제18권4호
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• pp.315-336
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• 2009

경상분지 북동부 일대의 제3기 결정질 응회암에서 발달하는 미세균열의 빈도수, 길이 및 밀도에 대한 분포특성을 도출하였다. 포항시 흥해읍 지역에서 채취한 3개 암석시료의 수평면 상에서 발달하는 134조의 미세균열은 박편의 확대사진을 통하여 구별하였다. 채취지점의 고도를 달리하는 3개 암석시료에 대한 미세균열의 길이-빈도 히스토그램에 대한 형태의 변화성을 도출하였다. 히스토그램들의 분포형태는 암석시료의 고도와 비례하여 음의 지수함수의 분포형에서 대수-정규의 분포형으로 점변한다. 다른 암석시료보다 고도가 낮은 암석시료 1의 분포형태는 넓은 길이분포를 보여주며, 다른 암석시료에 비하여 평균길이와 중앙값, 그리고 표준 편차가 높은 것이 특징이다. 한편 이와 같은 분포특성은 하부 경상누층군의 퇴적암에서 발달하는 절리의 길이분포와 부합한다. $N0{\sim}10^{\circ}W$의 방향을 중심으로 하여 NW 및 NE의 양쪽 방향으로 갈수록 보다 길이가 짧은 미세균열의 출현빈도수는 증가하며, $N80{\sim}90^{\circ}W$ 및 $N80{\sim}90^{\circ}E$의 방향에서 각각 우세하다. 이러한 분포특성은 미세균열 조들 사이의 생성시기의 상대적인 차이 그리고 보다 짧은 미세균열의 신규 발생을 의미한다. 한편 $N60{\sim}70^{\circ}W$(최대길이:1.18 mm) 및 $N0{\sim}10^{\circ}W$(최대길이:0.80 mm)의 방향에서는 길이가 가장 긴 미세균열을 볼 수 있으며, 이러한 유형의 미세균열은 빈도수에 비하여 숫적으로 매우 제한적이다. 방향각($\theta$)-빈도수(N), 총길이($L_t$), 평균길이($L_m$) 및 밀도($\rho$)의 종합 분포도의 전 영역은 상관곡선의 형태에 의거, 5개의 구간으로 분류할 수가 있다. 분포도에서 밀도곡선은 서북서-동남동($N70{\sim}80^{\circ}W$), 남-북~북북동-남남서($N0{\sim}10^{\circ}W/N10{\sim}20^{\circ}E$), 동북동-서남서($N50{\sim}60^{\circ}E$) 그리고 거의 동-서($N80{\sim}90^{\circ}E$)의 방향에서 각각 5개의 뚜렷한 정점을 보여준다. 특히 단층의 주방향은 밀도가 높은 방향각과 부합한다. 결과적으로 밀도곡선의 이러한 분포형태는 기존의 연구에서 시사한 대표적인 최대 주응력 방향을 반영한다.