• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.965-966
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• 2007

For practical electrical insulation design of high temperature superconducting (HTS) power apparatuses, knowledge of the dielectric behavior of insulators in cryogenic liquid such as liquid nitrogen ($LN_2$) is essential. So in this paper, we discussed experimental investigations of breakdown and V-t characteristics of several insulators such as Kapton and glass fiber reinforced plastic (GFRP) that are candidates of insulator for HTS apparatus in cryogenic liquid. And we investigated the degradation of these insulation samples after breakdown with the microscope and SEM photograph. Moreover, survival and hazard analysis was performed.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.9
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• pp.4077-4080
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• 2015

The chemokine receptor 4 (CXCR4) has been widely used in diagnosis and prognosis of colorectal cancer (CRC). However, there is no current consensus on the impact of CXCR4 on CRC patients. The purpose of this study was to evaluate the prognostic and clinicopathological importance of CXCR4 in CRC patients. Databases, such as PubMed, Cochrane library, CBM and EMBASE updated to 2014 were searched to include eligible articles. We analysed correlations between CXCR4 expression and clinicopathological features and overall survival (OS). A total of 1, 055 CRC patients from twelve studies were included in the study. The pooled odds ratios (ORs) which indicated CXCR4 expression was likely to be associated with TNM stage (OR=0.43, CI=0.34-0.55, P<0.00001), lymph node status (OR=2.23, CI=1.23-4.05, P=0.008) and vascular invasion (OR=2.21, CI=1.11-4.39, P=0.02). Poor overall survival of CRC cancer was found to be significantly related to CXCR4 overexpression (hazard ratio (HR) 1.36 CI=1.17-1.59, P<0.0001), whereas combined ORs revealed that CXCR4 expression had no correlation with gender or differentiation. Based on the published studies, CXCR4 overexpression in patients w ith CRC indicates poor survival outcome and clinicopathological factors.

• Journal of Korean Neurosurgical Society
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• v.52 no.4
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• pp.396-403
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• 2012

Objective : The predictors of cranioplasty infection after decompressive craniectomy have not yet been fully characterized. The objective of the current study was to compare the long-term incidences of surgical site infection according to the graft material and cranioplasty timing after craniectomy, and to determine the associated factors of cranioplasty infection. Methods : A retrospective cohort study was conducted to assess graft infection in patients who underwent cranioplasty after decompressive craniectomy between 2001 and 2011 at a single-center. From a total of 197 eligible patients, 131 patients undergoing 134 cranioplasties were assessed for event-free survival according to graft material and cranioplasty timing after craniectomy. Kaplan-Meier survival analysis and Cox regression methods were employed, with cranioplasty infection identified as the primary outcome. Secondary outcomes were also evaluated, including autogenous bone resorption, epidural hematoma, subdural hematoma and brain contusion. Results : The median follow-up duration was 454 days (range 10 to 3900 days), during which 14 (10.7%) patients suffered cranioplasty infection. There was no significant difference between the two groups for event-free survival rate for cranioplasty infection with either a cryopreserved or artificial bone graft (p=0.074). Intergroup differences according to cranioplasty time after craniectomy were also not observed (p=0.083). Poor neurologic outcome at cranioplasty significantly affected the development of cranioplasty infection (hazard ratio 5.203, 95% CI 1.075 to 25.193, p=0.04). Conclusion : Neurologic status may influence cranioplasty infection after decompressive craniectomy. A further prospective study about predictors of cranioplasty infection including graft material and cranioplasty timing is necessary.

• Radiation Oncology Journal
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• v.36 no.4
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• pp.325-331
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• 2018

Purpose: Soft tissue sarcoma (STS) is a rare and heterogeneous cancer with over 50 known subtypes. It is difficult to understand the role of adjuvant treatment in STS. We aimed to determine the benefits of adjuvant treatment for a rare STS subset: non-extremity STS with moderate chemosensitivity. Materials and Methods: We reviewed medical records from Pusan National University Hospital and Kosin University Gospel Hospital, which had detailed pathological reports on patients diagnosed between 2006 and 2016. The most important inclusion criterion was resection with curative intent. We grouped STS by chemosensitivity based on reported data and analyzed non-extremity STS with moderate chemosensitivity. Results: We investigated 142 patients with 20 pathological subtypes of STS. Eighty-six patients had extremity STS and 56 had non-extremity STS. Thirty-eight of 56 patients were categorized as having moderate chemosensitivity. Seventeen of 38 patients (44.7%) received adjuvant radiotherapy and 14 (36.8%) received adjuvant chemotherapy. A log-rank test showed longer disease-free survival (DFS) in the adjuvant radiotherapy group than in the group treated without adjuvant radiotherapy (not reached vs. 1.468 years, p = 0.037). Multivariate Cox proportional hazard analysis, with covariates including age, stage, resection margin, adjuvant chemotherapy, and adjuvant radiotherapy, revealed that adjuvant radiotherapy was associated with longer DFS (odds ratio = 0.369, p = 0.045). Overall survival was not correlated with adjuvant radiotherapy. Conclusion: Adjuvant radiotherapy may be associated with longer DFS in patients with non-extremity STS with moderate chemosensitivity.

• Annals of Hepato-Biliary-Pancreatic Surgery
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• v.28 no.2
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• pp.248-261
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• 2024

Backgrounds/Aims: This study aimed to investigate patterns and factors affecting recurrence after curative resection for pancreatic ductal adenocarcinoma (PDAC). Methods: Consecutive patients who underwent curative resection for PDAC (2011-21) and consented to data and tissue collection (Barts Pancreas Tissue Bank) were followed up until May 2023. Clinico-pathological variables were analysed using Cox proportional hazards model. Results: Of 91 people (42 males [46%]; median age, 71 years [range, 43-86 years]) with a median follow-up of 51 months (95% confidence intervals [CIs], 40-61 months), the recurrence rate was 72.5% (n = 66; 12 loco-regional alone, 11 liver alone, 5 lung alone, 3 peritoneal alone, 29 simultaneous loco-regional and distant metastases, and 6 multi-focal distant metastases at first recurrence diagnosis). The median time to recurrence was 8.5 months (95% CI, 6.6-10.5 months). Median survival after recurrence was 5.8 months (95% CI, 4.2-7.3 months). Stratification by recurrence location revealed significant differences in time to recurrence between loco-regional only recurrence (median, 13.6 months; 95% CI, 11.7-15.5 months) and simultaneous loco-regional with distant recurrence (median, 7.5 months; 95% CI, 4.6-10.4 months; p = 0.02, pairwise log-rank test). Significant predictors for recurrence were systemic inflammation index (SII) ≥ 500 (hazard ratio [HR], 4.5; 95% CI, 1.4-14.3), lymph node ratio ≥ 0.33 (HR, 2.8; 95% CI, 1.4-5.8), and adjuvant chemotherapy (HR, 0.4; 95% CI, 0.2-0.7). Conclusions: Timing to loco-regional only recurrence was significantly longer than simultaneous loco-regional with distant recurrence. Significant predictors for recurrence were SII, lymph node ration, and adjuvant chemotherapy.

• The Korean Journal of Applied Statistics
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• v.25 no.6
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• pp.959-975
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• 2012

Each year research institutions such as the Korea Employment Information Service(KEIS), a government institution established for the advancement of employment support services, and Job Korea, a popular Korean job website, announce first job waiting times after college graduation. This provides useful information understand and resolve youth unemployment problems. However, previous reports deal with the time as a completely observed one and are not appropriate. This paper proposes a new study on first job waiting times after college graduation set to 4 months prior to graduation. In Korea, most college students hunt for jobs before college graduation in addition, the full-fledged job markets also open before graduation. In this case the exact waiting time of college graduates can be right-censored. We apply a Cox proportional hazards model to evaluate the associations between first job waiting times and risk factors. A real example is based on the 2008 Graduates Occupational Mobility Survey(GOMS).

• Journal of Chest Surgery
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• v.55 no.2
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• pp.143-150
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• 2022

Background: The effectiveness of extracorporeal membrane oxygenation (ECMO) for patients with refractory cardiogenic shock or cardiac arrest is being established, and serum lactate is well known as a biomarker of end-organ perfusion. We evaluated the efficacy of pre-ECMO lactate for predicting 6-month survival in patients with acute coronary syndrome (ACS) undergoing ECMO. Methods: We reviewed the medical records of 148 patients who underwent veno-arterial (VA) ECMO for ACS between January 2015 and June 2020. These patients were divided into survivors and non-survivors based on 6-month survival. All clinical data before and during ECMO were compared between the 2 groups. Results: Patients' mean age was 66.0±10.5 years, and 116 (78.4%) were men. The total survival rate was 45.9% (n=68). Cox regression analysis showed that the pre-ECMO lactate level was an independent predictor of 6-month mortality (hazard ratio, 1.210; 95% confidence interval [CI], 1.064-1.376; p=0.004). The area under the receiver operating characteristic curve of pre-ECMO lactate was 0.64 (95% CI, 0.56-0.72; p=0.002; cut-off value=9.8 mmol/L). Kaplan-Meier survival analysis showed that the cumulative survival rate at 6 months was significantly higher among patients with a pre-ECMO lactate level of 9.8 mmol/L or less than among those with a level exceeding 9.8 mmol/L (57.3% vs. 31.8%, p=0.0008). Conclusion: A pre-ECMO lactate of 9.8 mmol/L or less may predict a favorable outcome at 6 months in ACS patients undergoing VA-ECMO. Further research aiming to improve the accuracy of predictions of reversibility in patients with high pre-ECMO lactate levels is essential.

• Korean Journal of Radiology
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• v.22 no.2
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• pp.159-167
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• 2021

Objective: The aim of this study was to compare the survival rates of Korean females aged 40 to 49 years with breast cancer detected by supplemental screening ultrasound (US) or screening mammography alone. Materials and Methods: This single-institution retrospective study included 240 patients with breast cancer (mean age, 45.1 ± 2.8 years) detected by US or mammography who had undergone breast surgery between 2003 and 2008. Medical records were reviewed for clinicopathologic characteristics and detection methods. Disease-free survival (DFS) and overall survival (OS) were compared between patients with breast cancer in the US and mammography groups using the log-rank test. Multivariable cox regression analysis was used to identify independent variables associated with DFS and OS. Results: Among the 240 cases of breast cancer, 43 were detected by supplemental screening US and 197 by screening mammography (mean follow-up: 7.4 years, 93.3% with dense breasts). There were 19 recurrences and 16 deaths, all occurring in the mammography group. While the US group did not differ from the mammography group in tumor stage, the patients in this group were more likely to undergo breast-conserving surgery and radiation therapy than the mammography group. The US group also showed better DFS (p = 0.016); however, OS did not differ between the two groups (p = 0.058). In the multivariable analysis, the US group showed a lower risk of recurrence (hazard ratio, 0.097; 95% confidence interval, 0.001-0.705) compared to the mammography group. Conclusion: Our study found that Korean females aged 40-49 years with US-detected breast cancer showed better DFS than those with mammography-detected breast cancer. However, there were no statistically significant differences in OS.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.425-432
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• 2019

This study examined the effects of livestock disease news, such as foot-and-mouth disease (FMD), collected by the Korea Press Foundation on BIGKinds on the consumption of beef and pork. The consumer purchase data were obtained from the Rural Development Administration's Agrifood consumer panel data. Survival analysis showed that the FMD news noted beef and pork, and the first purchase rate decreased due to FMD news. The time-dependent Cox proportional hazards model revealed all models to be significant. FMD news was significant in each model. In 2010, the Hazard Ratio of domestic and imported pork was 0.999, and the first purchase rate decreased 0.999 times for each additional FMD news item. On the other hand, the Hazard Ratio of pork in 2015 was 1.001, and the first purchase rate increased. In the case of beef, results similar to pork were shown. This study estimated the impact of consumer meat consumption disease news on the first purchases according to origin and meat. These results provide the necessary information for rational production and consumption activities. In addition, it can also be used for promotion by estimating the duration of livestock disease news.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.5
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• pp.2219-2224
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• 2012

Background: Circulating lymphocyte subsets reflect the immunological status and might therefore be a prognostic indicator in cancer patients. Our aim was to evaluate the clinical significance of circulating lymphocyte subset in gastric cancer (GC) cases. Methods: A retrospective study on a prevalent cohort of 846 GC patients hospitalized at Hospital from Aug 2006 to Jul 2010 was conducted. We calculated the patient's disease free survival (DFS) after first hospital admission, and hazard ratios (HR) from the Cox proportional hazards model. Results: Our findings indicated a significantly decreased percentage of CD3+, and CD8+ cells, a significantly increased proportion of $CD4^+$, $CD19^+$, $CD44^+$, $CD25^+$, NK cells, and an increased $CD4^+/CD8^+$ ratio in GC patients as compared with healthy controls (all P < 0.05). Alteration of lymphocyte subsets was positively correlated with sex, age, smoking, tumor stage and distant metastasis of GC patients (all P<0.05). Follow-up analysis indicated significantly higher DFS for patients with high circulating $CD19^+$ lymphocytes compared to those with low $CD19^+$ lymphocytes (P=0.037), with $CD19^+$ showing an important cutoff of $7.91{\pm}2.98%$ Conclusion: Circulating lymphocyte subsets in GC patients are significantly changed, and elevated CD19+ cells may predict a favorable survival.