• 터널과지하공간
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• 제30권4호
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• pp.359-381
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• 2020

벤토나이트 완충재에서의 열-수리-역학적 복합거동을 예측하기 위해 TOUGH2-MP/FLAC3D 시뮬레이터를 기반으로 개발된 Barcelona basic 모델(BBM) 해석모듈의 현장 적용성을 검토하고자 국제공동연구 DECOVALEX-2019 Task D에 참여하여 스위스 Grimsel Test Site의 현장시험(full-scale engineered barriers experiment, FEBEX) 모델링을 수행하고 현장시험에서 계측된 히터 파워, 온도, 상대습도, 응력, 포화도, 함수율 그리고 건조밀도를 계산 값과 비교하였다. 수치해석을 이용하여 시간에 따른 히터 파워와 온도 변화는 전반적으로 잘 재현되었지만, 히터 1과 히터 2에서의 파워 차이를 계산할 수는 없었으며 이를 개선하기 위해서는 FEBEX 터널 주변에 분포하는 황반암과 시험장치 및 벤토나이트 블록의 설치 공정을 반영할 필요가 있을 것으로 판단된다. 상대습도 변화와 분포 역시 전반적으로 잘 모사되었으나, 수치해석에서 히터 부근에서의 재포화과정이 상대적으로 빠르게 진행된 것으로 보아 수리모델에 대한 일부 수정이 필요할 것으로 보인다. 현장시험에서는 벤토나이트 완충재와 암반 사이에 틈이 존재하지만 수치해석에서는 완벽하게 접촉하고 있는 것으로 가정하였기 때문에 운영 초기의 응력 변화는 다소 차이를 보였지만, 전반적으로 유사한 경향을 보이는 것으로 나타났다. 해체 이후 측정한 포화도, 함수율, 그리고 건조밀도의 분포 역시 전반적으로 잘 재현되었지만, 건조밀도가 터널 중심과 히터부근에서 조금 크게 계산되어 벤토나이트 블록의 투수계수가 상대적으로 작은 값으로 반영되어 포화도와 함수율이 작게 계산된 것으로 보이며, 이를 개선하기 위해서는 건조밀도에 따른 투수계수 모델에 일부 수정이 필요할 것으로 판단된다. 본 연구의 결과를 토대로 수치모델을 수정하고 추가적인 연구를 수행한다면, 보다 나은 해석 결과와 벤토나이트 완충재에서의 THM 복합거동을 좀 더 현실적으로 예측할 수 있을 것으로 판단된다.

• Coupled systems mechanics
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• 제6권4호
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• pp.417-437
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• 2017

This paper shows a comparative study for design of reinforced concrete boundary combined footings of trapezoidal and rectangular forms supporting two columns and each column transmits an axial load and a moment around of the axis X (transverse axis of the footing) and other moment around of the axis Y (longitudinal axis of the footing) to foundation to obtain the most economical combined footing. The real soil pressure acting on the contact surface of the footings is assumed as a linear variation. Methodology used to obtain the dimensions of the footings for the two models consider that the axis X of the footing is located in the same position of the resultant, i.e., the dimensions is obtained from the position of the resultant. The main part of this research is to present the differences between the two models. Results show that the trapezoidal combined footing is more economical compared to the rectangular combined footing. Therefore, the new model for the design of trapezoidal combined footings should be used, and complies with real conditions.

• Asian Pacific Journal of Cancer Prevention
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• 제15권16호
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• pp.6673-6678
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• 2014

Background: To investigate the prognostic value of serum PIVKA-II (prothrombin induced by the absence of vitamin K or antagonist-II) in BCLC (Barcelona Clinic Liver Cancer) 0-A hepatocellular carcinoma (HCC) patients after curative resection. Materials and Methods: Preoperative sera were collected from 140 patients with BCLC 0-A HCCs undergoing curative resection during 2011-2012 in Zhongshan Hospital. Follow-up ended on November 2013. ELISA was used to detect the serum concentrations of preoperative PIVKA-II. The prognostic value of PIVKA-II and other clinicopathological factors was analyzed by the Kaplan-Meier method and the multivariate Cox proportional hazards model. Results: During follow-up, 39 of 140 patients suffered recurrence and the 1-year recurrence rate was 27.9%. The high-PIVKA-II expression group had lower 1-year time to progression (TTP) compared with the low-expression group (54.8% vs 20.2%, p<0.001). Patients with high preoperative PIVKA-II expression showed a relatively higher risk of developing postoperative recurrence than those with low expression in the low-recurrence-risk subgroups, including ${\alpha}$-fetoprotein ${\leq}400ng/mL$ (45.4% vs 16.7%; p=0.006), tumor size ${\leq}5cm$ (54.2% vs 18.1%; p<0.001), single tumor (56.0% vs 19.1%; p<0.001), absence of satellite lesions (53.3% vs 19.8%; p=0.001), absence of vascular invasion (52.6% vs 14.9%; p=0.002), and Edmondson stage I/II (60.9% vs 20.3%; p<0.001). PIVKA-II was the strongest independent prognostic factor for TTP (hazard ratio, 2.877; 95% CI 1.524-5.429; p=0.001). Conclusions: Elevated PIVKA-II is associated with early recurrence of BCLC 0-A HCC after curative resection and can be considered a novel prognostic predictor.

• Gut and Liver
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• 제12권6호
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• pp.714-721
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• 2018

Background/Aims: Recently reported prognostic models for primary biliary cholangitis (PBC) have been shown to be effective in Western populations but have not been well-validated in Asian patients. This study aimed to compare the performance of prognostic models in Korean patients and to investigate whether inflammation-based scores can further help in prognosis prediction. Methods: This study included 271 consecutive patients diagnosed with PBC in Korea. The following prognostic models were evaluated: the Barcelona model, the Paris-I/II model, the Rotterdam criteria, the GLOBE score and the UK-PBC score. The neutrophil-to-lymphocyte ratio (NLR) was analyzed with reference to its association with prognosis. Results: For predicting liver transplant or death at the 5-year and 10-year follow-up examinations, the UK-PBC score (areas under the receiver operating characteristic curve [AUCs], 0.88 and 0.82) and GLOBE score (AUCs, 0.85 and 0.83) were significantly more accurate in predicting prognosis than the other scoring systems (all p<0.05). There was no significant difference between the performance of the UK-PBC and GLOBE scores. In addition to the prognostic models, a high NLR (>2.46) at baseline was an independent predictor of reduced transplant-free survival in the multivariate analysis (adjusted hazard ratio, 3.74; p<0.01). When the NLR was applied to the prognostic models, it significantly differentiated the prognosis of patients. Conclusions: The UK-PBC and GLOBE scores showed good prognostic performance in Korean patients with PBC. In addition, a high NLR was associated with a poorer prognosis. Including the NLR in prognostic models may further help to stratify patients with PBC.

• Asian Pacific Journal of Cancer Prevention
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• 제16권10호
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• pp.4421-4427
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• 2015

Objectives: To investigate the prognosis significance of preoperative serum alpha-fetoprotein (AFP) and the correlation with clinicopathological factors of hepatocellular carcinoma (HCC) patients who underwent hepatectomy. Materials and Methods: Clinicopathological data of retrospective analysis were collected for 251 HCC patients undergoing hepatectomy in this study. According to preoperative AFP level, patients were categorized into AFP-negative (0-20ng/mL) and AFP-positive (>20 ng/mL) groups for Kaplan-Meier analysis and Cox proportional hazard regression modeling. Results: The results demonstrated that increased AFP was associated with longer prothrombin time (PTs), liver capsule invasion, low grade differentiation, and late Barcelona Clinic Liver Center (BCLC) stage. Moreover, the female patients had a greater prevalence of increased preoperative AFP than male patients [284.8 (3.975-3167.5) vs (3.653-140.65); Z-2.895, p=0.004]. The 1-, 3-, and 5-year recurrence-free survival (RFS) rates were 78.1, 57.5, and 40.6 % in the AFP-negative group and 61.8, 37.7, and 31.4 %, respectively, in the AFP-positive group (log-rank test 8.312, p=0.004). The 1-, 3-, and 5-year overall survival (OS) rates were 94.4, 83.8, and 62.3% in the AFP-negative group and 87.2, 60.0, and 36.7%, respectively, in the AFP-positive group. The difference was statistically significant (log-rank test, 16.884, p=0.000). Cox proportional-hazards model identified preoperative AFP to be an independent prognostic predictor of overall survival. Conclusions: Preoperative serum AFP is an independent predictor of prognosis among HCC patients following surgical resection. Female patients have a higher preoperative AFP than their male counterparts.

• 식물분류학회지
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• 제46권4호
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• pp.361-370
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• 2016

한반도 남동부에 위치한 주왕산 국립공원과 그 인접산지는 식물 개체군의 유전자 이동에 대한 물리적 장벽의 영향을 시험하기 위한 훌륭한 모델 시스템이다. 우리는 식물종의 경우, 격리된 집단이 연속적인 분포를 보이는 집단보다 유전적인 분화 정도가 더 클 것으로 예측했다. 바위채송화 대부분의 집단은 4곳의 고립된 계곡에서 생육하며, 10개 집단에서 12 종류의 알로자임 유전좌위를 사용하여 유전적 다양성과 구조를 평가했다. 저자들은 이 연구와 기존 연구된 둥근잎꿩의비름(4곳 계곡에서 격리되어 생육)과 기린초(상대적으로 연속적으로 분포) 결과와 비교했다. 우리는 기린초 집단내 유전적 변이가 중간 수준임을 발견했다($H_e=0.112$). 바위채송화 집단간 분기 수준도 중간 수준($F_{ST}=0.250$)이었고 예상대로 둥근잎꿩의비름(0.261)과 유사했지만 기린초(0.165)보다 상당히 높았다. 분자분산분석(AMOVA) 결과 바위채송화와 둥근잎꿩의비름은 기린초(4%)보다 계곡간 변이(각각 19%) 비율이 높았다. STRUCTURE 프로그램 분석에 의하면 대부분의 이런 변이는 중간에 있는 두 계곡간의 유전적 조성 차이 때문이다. 저자들은 종간에 관찰된 분화 수준의 차이(즉, 기린초 대 바위채송화와 둥근잎꿩의비름)는 연구 지역 내의 그들의 분포 차이에 기인한다고 결론지었다.