• 보건교육건강증진학회지
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• 제21권4호
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• pp.1-13
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• 2004

This study conducted descriptive literature review on adolescent smoking and the related factors to realize significance of adolescent smoking onset in Korea and to identify risk factors of smoking incidence. Korean adolescent smoking status was generated based on the cumulated data of the Korean Association of Smoking and Health. Risk factors of adolescent smoking were identified based on 18 studies written in English, with cross-sectional research design and published as a peer-reviewed journal article between 1994 and 2003. The results were as follows. 1. Korean adolescent smoking rate was the highest among OECD affiliated countries; in particular, male adolescent smoking incidence was very serious. 2. Risk factors related to smoking of adolescent population were personal factor, friend factor, family factor, and mass-media factor. Demographic characteristics, attitudes on smoking, and willingness of smoking, and health behaviors were selected as personal factor of smoking. 3. Best friends smoking was a strong factor of students' smoking set. Prevalent popularity of smoking in peer-group allowed students to feel free to smoking. 4. Concerning family factor related to smoking status, parents' smoking and sibling's smoking were significant indicators of adolescent smoking status. 5. Seeing smoking behaviors and scenes through films, TV shows, drama, and advertisement was a significant risk factor of adolescent smoking status.

• Radiation Oncology Journal
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• 제34권4호
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• pp.297-304
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• 2016

Purpose: To investigate the outcomes of postoperative radiotherapy (RT), in patients with extrahepatic bile duct (EHBD) cancer by comparing the survival rate between patients undergoing surgery alone or surgery plus postoperative RT, and to identify the prognostic factors affecting survival. Materials and Methods: Between 2000 and 2013, 52 patients with EHBD cancer underwent surgical resection. Of these, 33 patients did not receive postoperative RT (group I), and 19 patients did (group II). R1 resection was significantly more frequent in group II. The median radiation dose was 5,040 cGy. Results: The 3-year overall survival (OS) rate for group I and group II was 38% and 56%, respectively (p = 0.274). The 3-year disease free survival (DFS) rate for group I and group II was 20% and 31%, respectively (p = 0.049), and the 3-year loco-regional recurrence free survival (LRFS) rates were 19% and 58%, respectively (p = 0.002). Multivariate analyses showed that postoperative RT and lymphovascular invasion were independent prognostic factors for DFS and LRFS. Overall, 42 patients (80%) experienced treatment failure. Distant metastasis was the predominant pattern of failure in group II. Conclusion: Postoperative RT after surgical resection appeared to improve the loco-regional control and DFS rate. More effort is needed to reduce distant metastasis, the major pattern of failure, in patients who receive postoperative RT.

• 신재생에너지
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• 제7권4호
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• pp.10-17
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• 2011

Recently, electricity industry is facing high market uncertainty which has ever had and which increase risks in power market. In this study, we analyze risk factors such as discount rates, initial investment (overnight cost), plant factor, fuel cost, carbon price, etc, for the perspective of investor. For the analysis of risk factors, we used LCOE method. The results of this study show that renewable energy is more affected by plant factor and overnight cost than other risk factors. First, Renewable energy has higher proportion of overnight cost in the total investment than that of other technologies. Second, renewable energy is free of fuel cost and carbon price so plant factor is the most important factor, in other words, competitiveness of renewable energy depends on plant factor. Furthermore, we conducted economic feasibility of wind power and PV in domestic case study. The minimum requirement condition to get profitability is that plant factor 15% and overnight cost \6,000,000/kW and 26%, \2,200,000/kW for PV and Wind Power, respectively.

• 산업경영시스템학회지
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• 제44권1호
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• pp.1-8
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• 2021

As a nation experiencing rapid economic growth, South Korea and its government have made a continuous effort toward efficient research investments to achieve transformation of the Korean industry for the fourth industrial revolution. To achieve the maximum effectiveness of the research investments, it is necessary to evaluate its funding's worth and default risk. Thus, incorporating the concepts of the Black-Scholes-Merton model and the Greeks, this study develops a default-risk evaluation model in the foundation of a system dynamics methodology. By utilizing the proposed model, this study estimates the monetary worth and the default risks of research funding in the public and private sectors of Information and Communication technologies, along with the sensitivity of the R&D economic worth of research funding to changes in a given parameter. This study finds that the public sector has more potential than the private sector in terms of monetary worth and that the default risks of three types of research funding are relatively high. Through a sensitivity analysis, the results indicate that uncertainty in volatility, operation period, and a risk-free interest rate has trivial impacts on the monetary worth of research funding, while volatility has large impacts on the default risk among the uncertain factors.

• Asian Pacific Journal of Cancer Prevention
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• 제14권12호
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• pp.7101-7106
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• 2013

Background: The prognosis of patients with hepatocellular carcinoma (HCC) after curative resection varies greatly. Few studies had investigated the risk factors for early recurrence (recurrence-free time ${\leq}$ 1 year) of hepatitis B virus (HBV)-related HCCs meeting Milan criteria. Methods: A retrospective analysis was performed on the 224 patients with HCC meeting Milan criteria who underwent curative liver resection in our center between February 2007 and March 2012. The overall survival (OS) rate, recurrence-free survival (RFS) rate and risk factors for early recurrence were analyzed. Results: After a median follow-up of 33.3 months, HCC reoccurred in 105 of 224 patients and 32 died during the period. The 1-, 3- and 5-year OS rates were 97.3%, 81.6% and 75.6% respectively, and the 1-, 3- and 5-year RFS rates were 73.2%, 53.7% and 41.6%. Cox regression showed alpha-fetoprotein (AFP) > 800 ng/ml (HR 2.538, 95% CI 1.464-4.401, P=0.001), multiple tumors (HR 2.286, 95% CI 1.123-4.246, P=0.009) and microvascular invasion (HR 2.518, 95% CI 1.475-4.298, P=0.001) to be associated with early recurrence (recurrence-free time ${\leq}$ 1-year) of HCC meeting Milan criteria. Conclusions: AFP > 800 ng/ml, multiple tumors and microvascular invasion are independent risk factors affecting early postoperative recurrence of HCC. In addition resection appears capable of replacing liver transplantation in some situations with safety and a better outcome.

• Asian Pacific Journal of Cancer Prevention
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• 제15권2호
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• pp.925-928
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• 2014

Background: Gestational trophoblastic neoplasia (GTN) is a spectrum of disease with abnormal trophoblastic proliferation. Treatment is based on FIGO stage and WHO risk factor scores. Patients whose score is 12 or more are considered as at extremely high risk with a high likelihood of resistance to first line treatment. Optimal therapy is therefore controversial. Objective: This study was conducted in order to summarize the regimen used for extremely high risk or resistant GTN patients in our institution the in past 10 years. Materials and Methods: All the charts of GTN patients classified as extremely high risk, recurrent or resistant during 1 January 2002 to 31 December 2011 were reviewed. Criteria for diagnosis of GTN were also assessed to confirm the diagnosis. FIGO stage and WHO risk prognostic score were also re-calculated to ensure the accuracy of the information. Patient characteristics were reviewed in the aspects of age, weight, height, BMI, presenting symptoms, metastatic area, lesions, FIGO stage, WHO risk factor score, serum hCG level, treatment regimen, adjuvant treatments, side effects and response to treatment, including disease free survival. Results: Eight patients meeting the criteria of extremely high risk or resistant GTN were included in this review. Mean age was 33.6 years (SD=13.5, range 17-53). Of the total, 3 were stage III (37.5%) and 5 were stage IV (62.5%). Mean duration from previous pregnancies to GTN was 17.6 months (SD 9.9). Mean serum hCG level was 864,589 mIU/ml (SD 98,151). Presenting symptoms of the patients were various such as hemoptysis, abdominal pain, headache, heavy vaginal bleeding and stroke. The most commonly used first line chemotherapeutic regimen in our institution was the VAC regimen which was given to 4 of 8 patients in this study. The most common second line chemotherapy was EMACO. Adjuvant radiation was given to most of the patients who had brain metastasis. Most of the patients have to delay chemotherapy for 1-2 weeks due to grade 2-3 leukopenia and require G-CSF to rescue from neutropenia. Five form 8 patients were still survived. Mean of disease free survival was 20.4 months. Two patients died of the disease, while another one patient died from sepsis of pressure sore wound. None of surviving patients developed recurrence of disease after complete treatment. Conclusions: In extremely high risk GTN patients, main treatment is multi-agent chemotherapy. In our institution, we usually use VAC as a first line treatment of high risk GTN, but since resistance is quite common, this may not suitable for extremely high risk GTN patients. The most commonly used second line multi-agent chemotherapy in our institution is EMA-CO. Adjuvant brain radiation was administered to most of the patients with brain metastasis in our institution. The survival rate is comparable to previous reviews. Our treatment demonstrated differences from other institutions but the survival is comparable. The limitation of this review is the number of cases is small due to rarity of the disease. Further trials or multicenter analyses may be considered.

• Parasites, Hosts and Diseases
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• 제43권2호
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• pp.47-50
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• 2005

A survey was carried out from August to December 2004 in Pusan, Korea to document the presence of free-living amoeba (FLA), including the genus Acanthamoeba, in both contact lens storage cases and domestic tap water. Acanthamoeba was isolated from $5(4.2\%)$ in 120 contact lens storage cases. Four house tap water samples from residents, whose contact lens storage cases had been contaminated by Acanthamoeba, were also found to be contaminated with Acanthamoeba. Therefore, the contamination rate of FLA and Acanthamoeba in domestic tap water was investigated in order to examine the role of domestic tap water in Acanthamoeba contamination of contact lens storage cases. FLA and Acanthamoeba were identified in $97(46.8\%)\;and\;16(7.7\%)$ of the 207 domestic tap water samples, respectively. There were no significant differences between the contamination rates of FLA in tap water according to the filtration plant of origin. No FLA was detected in the tap water directly supplied by the water purification plants. Water storage tanks appear to promote FLA colonization, including Acanthamoeba, in domestic tap water. This increases the risk of Acanthamoeba contamination in contact lens storage cases as well as increasing the risk of Acanthamoeba keratitis.

• Journal of Korean Neurosurgical Society
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• 제65권3호
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• pp.469-478
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• 2022

Objective : Cranial base chordomas are rare, but their treatment is challenging. Tumor recurrence is still common despite improvements in microsurgical techniques and postoperative radiotherapy. We retrospectively analyzed the course of treatment, overall survival, and recurrence/progression of chordomas over the past 10 years. Methods : We retrospectively reviewed 50 patients who underwent surgery at Tianjin Huanhu Hospital between 2010 and 2020 and were pathologically diagnosed with chordomas. Tumor resection was performed within the maximum safe range in all patients; the extent of resection was evaluated by imaging; and the incidence of complications, recurrence or progression, and overall survival were assessed. Results : Fifty patients were divided into the low-risk group (LRG) and high-risk group (HRG) based on the cranial chordoma grading system (CCGS). The Karnofsky Performance Scale scores and gross total resection rate of the LRG were significantly higher than those of the HRG (p<0.05). The incidence of complications and mortality in the LRG were lower than those of HRG. The analysis of cumulative survival and cumulative recurrence free survival/progression free survival (RFS/PFS) showed no statistical differences in the extent of resection for survival, recurrence, or progression. Univariate and multivariate analyses showed that Ki-67 was significantly associated with tumor recurrence and was an independent hazard factor (p=0.02). Conclusion : The CCGS can help neurosurgeons anticipate surgical outcomes. Pathological results are important in evaluating the possibility of tumor recurrence, and postoperative radiotherapy improves overall survival and RFS/PFS.

• Radiation Oncology Journal
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• 제12권1호
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• pp.91-98
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• 1994

Purpose: Despite apparently complete resection of cancer of the rectum, local recurrence rate was high. Radiation therapy has been used either alone or in combination with chemotherapy as an adjunct to surgery to reduce the risk of recurrence. This study was designed to evaluate the prognostic factors, survival rate and local recurrence rate of the rectal cancer who had received postoperative radiation therapy by retrospective analysis. Method: From 1982 to 1990, 63 patients with cancer of the rectum surgically staged as B2 or C disease received postoperative adjuvant radiation therapy after curative resection of tumor for cure. Postoperative radiation therapy was given to the whole pelvis(mean dose: 5040 cGy in 5-6weets) and perineum was included in irradiated field in case of abdominoperineal resection. Results: Three-year actuarial survival rate was 73.2$ \% $ overall, 87.7$ \% $ in stage B2+3 and 62.9$ \% $ in stage C2+3. Three-year disease-free survival rate was 69.5$ \% $ overall, 87.7$ \% $ in stage B2+3 and 56.8$ \% $ in stage C2+3, Three-year disease-free survival rate in anterior resection was 77.8$ \% $ and 44.4$ \% $ in abdominoperineal resection. The local recurrence rate was 15.9$ \% $ and distant failure rate was 20.6$ \% $. Severe late complication was small bowel obstruction in 6 patients and surgery was required in 4 patients(6.3$ \% $). The prognostic factors were stage(p=0.0221) and method of surgery(p= 0.0414) (anterior resection vs abdominoperineal resection). Conclusion: This study provides evidence supporting the use of postoperative radiation therapy for reducing the local recurrence rate in patients who have had curative resection of rectal cancer with involvement of perirectal fat or regional nodes or both(stage B2 and C).

• 기술혁신학회지
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• 제5권2호
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• pp.141-151
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• 2002

Many technology investment projects can be considered as set of sequential options. A compound real option can be used for evaluating sequential technology investment decisions under significant uncertainty and measuring its value. In this paper, the formula developed by Geske and Johnson(1984) and Buraschi and Dumas(2001) was applied to evaluate the technology investment with related double real option. Also double real option was com-pared with net present value method and multiple linear regression model was used to assess the partial effects of risk free rate and log-term volatility on its value.