• 상하수도학회지
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• 제23권3호
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• pp.305-313
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• 2009

This paper provides a method for evaluating a residual life of water mains using a proportional hazard model(PHM). The survival time of individual pipe is defined as the elapsed time since installation until a break rate of individual pipe exceeds the Threshold Break Rate. A break rate of an individual pipe is estimated by using the General Pipe Break Model(GPBM). In order to use the GPBM effectively, improvement of the GPBM is presented in this paper by utilizing additional break data that is the cumulative number of pipe break of 0 for the time of installation and adjusting a value of weighting factor(WF). The residual lives and hazard ratios of the case study pipes of which the cumulative number of pipe breaks is more than one is estimated by using the estimated survival function. It is found that the average residual lives of the steel and cast iron pipes are about 25.1 and 21 years, respectively. The hazard rate of the cast iron pipes is found to be higher than the steel pipes until 20 years since installation. However, the hazard rate of the cast iron pipes become lower than the hazard rates of the steel pipes after 20 years since installation.

• Radiation Oncology Journal
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• 제19권4호
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• pp.312-318
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• 2001

목적 : 고위험 유방암 환자의 수술 후 방사선치료 후 국소 재발율, 생존율 및 예후인자를 후향적 분석하여 방사선치료의 역할을 규명하고자 하였다. 대상 및 방법 : 1984년부터 1995년까지 유방암으로 변형 근치적 유방절제술 후 종양의 크기가 4 cm 이상이거나, 4 cm 미만이나 액와 림프절의 전이가 있는 환자 중 방사선치료를 완료한 48명을 대상으로 하였다. 중앙 연령은 47세 ($31\~79$세)이었으며, 종양의 크기가 2 cm미만 1명, $2\~5\;cm$ 15명, 5 cm이상이 32명이었다. 액와림프절에 전이된 환자는 32명이었다. 흉벽과 국소림프절에 방사선치료받은 환자는 42명, 흉벽만 받은 환자는 6명이었으며 방사선량은 1일 1회(1.8 Gy)로 총 선량은 50.4 Gy이었다. 48명 중 18명$(38\%)$은 5-FU를 기본으로 하는 항암화학요법을 방사선치료 전 혹은 후에 투여하였다. 중앙 추적기간은 61개월이었다. 결과 : 국소 재발율은 $8\%$, 원격전이율은 $14\%$이었다. 전체환자의 5년 생존율은 $63\%$, 무병생존율은 $62\%$이었으며 중앙생존기간은 67개월이었다. 병기에 따른 5년 생존율은 IIB는 $70\%$, IIIA는 $58\%$이었으며, 생존율에 미치는 예후인자는 병기이었다(p=0.0076). 결론 : 고 위험군의 유방암 환자의 수술 후 방사선치료는 국소재발율은 감소시키고 생존율을 향상시킬 수 있으며, 생존율에 영향을 주는 인자는 병기이었다.

• 한국가축번식학회지
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• 제16권2호
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• pp.117-123
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• 1992

This Study was carried out ot investigate the effects of concentration and equilibration time of cryoprotective aagents on survival rate of slowly and ultrarapidly frozen porcine embryos. The porcine embryos following dehydration by cryoprotective agents and 0.25M sucrose were slowly freezed(from 2$0^{\circ}C$ to -7$^{\circ}C$/-1$^{\circ}C$/min., from -7$^{\circ}C$ to -35$^{\circ}C$/-0.2$^{\circ}C$/min., from -35$^{\circ}C$ to -38$^{\circ}C$/-0.3$^{\circ}C$/min.) by Cell Freezer and directly plunged into liquid nitrogen and thawed in 38$^{\circ}C$ water bath. Survival rate was defined as development rate to the morula and blastocyst stage after in vitro culture or by FDA test. The results are summarized as follows : 1. The survival rates of porcine embryos after slow frozen-thawing in the freezing medium of 0.25M sucrose added 2.0M glycerol, 3.0M DMSO, 2.0M propanediol or 2.0M glycerol＋2.0M propanediol was 80.6, 84.7, 75.0 or 78.8%, respectively. 2. The survival rates of porcine embryos after slow frozen-thawing in the freezing medium of 0.50M sucrose added 2.0M glycerol, 3.0M DMSO, 2.0M propanediol or 2.0M glycerol＋2.0M propanediol was 80.9, 82.4, 73.1 or 77.1%, respectively. 3. The survival rates of porcine embryos after ultrarapid frozen-thawing in the freezing medium of 0.25M sucroese added 2.0M glycerol, 3.0M DMSO, 2.0M propanediol or 2.0M glycerol＋2.0M propanediol was 65.3, 68.6, 63.2 or 59.9%, respectively. 4. The survival rates of porcine embryos after ultrapid frozen-thawing in the freezing medium of 0.50M sucrose added 2.0M glycerol, 3.0M DMSO, 2.0 propanediol or 2.0M glycerol＋2.0M propanediol was 67.5, 62.9, 56.9, or 62.8%, respectively. 5. The higher survival rate of porcine embryos was attained at the short period ofequilibration time(5min.) in the freezing medium added 0.25M sucrose and 3.0 DMSO compared to those of 10 or 20min. equilibration time in the same condition.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2017년도 공동학술발표회
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• pp.170-170
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• 2017

• Journal of the Korean Data and Information Science Society
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• 제11권2호
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• pp.225-233
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• 2000

수명시험에서 시험에 장기간 노출된 대상 부품이나 실험 대상자의 수명은 관측되는 경우보다 관측중단이 일어나기가 쉽다. 이와 같은 경우에 임의중단모형에서 생존함수 추정량으로 흔히 이용되는 Kaplan과 Meier의 추정량은 수명분포의 오른쪽 꼬리부분에서 심각한 편의가 발생된다. 이러한 문제점에 대한 대안으로 정상적으로 관측된 최장수명보다 큰 관측중단수명이 많은 극단적인 오른쪽 관측중단모형에서 새로운 비모수적 생존함수 추정량을 제안하고 그 특성을 몬테칼로 모의실험을 통하여 기존의 추정량과 비교 분석하였다.

• Asian Pacific Journal of Cancer Prevention
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• 제13권11호
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• pp.5735-5739
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• 2012

Background: Malignant mesothelioma (MM) is an insidious tumor with poor prognosis, arising from mesothelial surfaces such as pleura, peritoneum and pericardium. We here aimed to evaluate the demographic, clinical, and radiological features of patients with MM followed in our center as well as their survival. Methods: The study included 228 patients (131 male, 97 female) who were followed up in our institution between 1993 and 2010 with the diagnosis of MM. Results: The mean age was 59.1 years in men and 58.7 years in women and the sex ratio was 1.4:1 in favor of males. Environmental asbestos exposure was present in 86% of the patients for a mean duration of $40{\pm}20$ years (range: 3-70). Pleural effusion and thoracic/abdominal pain were the most common presenting signs and symptoms (70.2% and 57.8%, respectively). One hundred-thirteen (66%) patients were treated with platinum-based combination chemotherapy (PBCT) plus supportive care (SC) and 67 (34%) patients received SC alone. The median follow-up time was 10.0 months. The median overall survival was significantly improved with PBCT plus SC compared to SC alone (11.4 vs. 5.1 months; p=0.005). The 6, 12, 18, and 24-month survival rates were significantly improved with PBCT plus SC compared to SC alone (72%, 43%, 19%, and 2% vs. 49%, 31%, 11%, and 1%). Conclusion: The survival of patients with MM improved in patients treated with PBCT. The survival advantage continued 12- and 24-month after the initial time of combination chemotherapy.

• 한국가축번식학회지
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• 제16권4호
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• pp.317-323
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• 1993

This study was carried out to study effects of the addition level of acetamide and non-permeable cryoprotectants(Ficoll, sucrose) in VS(20% glycerol＋10% ethyleneglycol) and equilibration time on the survival of vitrified mouse morulae. The results are summarized as follows: 1. When 10, 15 and 20% of acetamide were added to the new vitrification solution(20G 10E), FDA-scores of embryos were 4.4(control), 4.4(10%), 3.6(15, 20%), respectively. The addition of acetamide did not affect the survival of forzen-thawed morulae(P<0.05). 2. The survival rate betwen 5 min(3.5) and 10 min(4.6), 10 min(4.6) and 20 min(3.2) of equilibration in 10% sucrose, and 20 min(3.2) and 5 min(4.0), or 10 min(4.3) in 20% sucrose were significantly different(P<0.05). The highest survival(4.6) rate was obtained in mouse morulae equilibrated in VS(20G 10E) containing 10% sucrose for 10 minutes. 3. FDA-score of morulae frozen in the new vitrification solution containing 0, 10, 20 and 30% Ficoll was 4.5, 4.2, 4.4 and 4.6, respectively and had no significant effect among concentrations of Ficoll(P>0.05). The development rate after culture(24h) was 89%(20% Ficoll) and 93%(30% Ficoll), respectively.

• Archives of Plastic Surgery
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• 제47권5호
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• pp.444-450
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• 2020

Background Fingertip injuries are the most common type of traumatic injury treated at emergency departments and require prompt and adequate interventions for favorable wound survival outcomes. Hyperbaric oxygen (HBO₂) therapy is well known for its many positive effects on wound healing. We hypothesized that treatment with HBO₂ would improve the graft survival outcomes of amputated fingertip injuries treated with composite grafts. Methods This retrospective observational study included fingertip amputations that were treated between January 2013 and December 2017. A conventional group and an HBO₂ therapy group were statistically compared to evaluate the effect of HBO₂ treatment. Graft survival was categorized as either success or failure. Results Among 55 cases (digits), 34 digits were conventionally treated, while 21 digits were treated with HBO₂. No statistically significant differences were observed between the groups with regard to general characteristics. Among patients with guillotine-type injuries, the composite graft success rate was statistically significantly higher in the group that received HBO₂ therapy than in the conventional group (P=0.0337). Overall, the HBO₂ group also demonstrated a statistically significantly shorter healing time than the conventional group (P=0.0075). As such, HBO₂ treatment facilitates composite graft survival in cases of fingertip injury. Conclusions HBO₂ treatment was associated with an increased composite graft survival rate in guillotine-type fingertip injuries and reduced the time required for grafts to heal.

• 한국패류학회지
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• 제32권1호
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• pp.37-43
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• 2016

This study was carried out to determine the optimal water temperature for the embryonic development and laboratory culture of larvae of an intertidal mud snail, Nassarius festivus. The embryos and hatched veliger larvae of N. festivus were incubated at six different temperatures (5, 10, 15, 20, 25 and $30^{\circ}C$). Developmental time for each stage decreased as water temperature increased. The elapsed time to develop to the veliger larva at 15, 20, 25 and $30^{\circ}C$ was 559, 155, 131 and 103 hrs, respectively. At 5 and $10^{\circ}C$, embryo developed to veliger larvae but failed to hatch out of the egg capsule. In contrast, all embryos successfully hatched in the temperature range from 15 to $30^{\circ}C$. The biological minimum temperature during the embryonic development of N. festivus was estimated to be $9.5{\pm}0.4^{\circ}C$. The cumulative water temperatures for blastula, gastrula and veliger stages were calculated as $111{\pm}84$, $486{\pm}185$, $1,164{\pm}72^{\circ}C$, respectively. Temperature also affected the larval survival. Five days after hatching, more than 84% of larvae survived at all experimental temperatures. However, survival began to decrease after 6 days. It was 0% at $30^{\circ}C$. Survival of larvae incubated for 8 days was higher at 15 and $20^{\circ}C$ than other experimental temperatures. We therefore suggest that the optimal range of temperature for embryonic development and larval survival of N. festivus is $15-20^{\circ}C$.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제35권1호
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• pp.1-12
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• 2013

Purpose: Vascular endothelial growth factor (VEGF)-C and its tyrosine kinase receptor, VEGF receptor (VEGFR)-3 are recently known to have lymphangiogenic activities in various tumor types. In this study, we determined whether the expression of lymphangiogenic factors correlate with nodal metastasis or survival in a nude mouse model of oral squamous cell carcinoma (OSCC). Methods: Three OSCC cells (KB, SCC4, SCC9) were xenografted into the right mandibular gland of athymic nude mice. The mice were followed for tumor development and growth, and the mice were sacrificed when they had lost more than 20% of their initial body weight, or the diameter of the induced tumor exceeds 20 mm. After necropsy, the murine tumors were examined histologically and radiologically (micro-positron emission tomography computed tomography) for regional or distant metastasis. We performed immunohistochemical assays with anti-VEGF-C, VEGFR-3, CD105, and D2-40 antibodies. Immunofluorescence double staining for LYVE-1/CD31 was also performed. To quantify the VEGF-C and VEGFR-3 level in the cancer tissue, Western blotting was performed. Finally, we determined the correlation between the degree of expression of VEGF-C/VEGFR-3 and the mean survival time. Results: OSCC tumor cells into the mandibular gland of the nude mice successfully resulted in the formation of recapitulating orthotopic tumor. Tumor cells of the induced tumor did not express VEGF-C. VEGF-C/VEGFR-3 expression was mainly distributed in the endothelial cells of the stromal area. There were no correlation between the degree of expression of VEGF-C/VEGFR-3 and the mean survival time of mice injected with different OSCC cell lines. Conclusion: An recapitulating orthotopic model of OSCC in nude mice was established, which copies the cervical nodal metastasis of human OSCC. Overexpression of lymphangiogenic factors seems to have no effect on survival of hosts in this in vivo experiment.