• 제목/요약/키워드: Risk-free Rate

검색결과 203건 처리시간 0.027초

Accuracy of c-KIT in lung cancer prognosis; a systematic review protocol" instead of c-KIT Expression in Lung Cancer Prognostic Evaluation - a Systematic Review Protocol

  • Roudi, Raheleh;Kalantari, Elham;Keshtkar, Abbas;Madjd, Zahra
    • Asian Pacific Journal of Cancer Prevention
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    • 제17권2호
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    • pp.863-866
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    • 2016
  • Background: Extensive efforts have been made to investigate c-KIT expression in lung cancer specimens and its correlation with clinical outcomes, but the issue remains unresolved. Thus, this study will be conducted to clarify the prognostic value of c-KIT expression in lung cancer patients. Materials and Methods: We will search Pubmed, SCOPUS, and ISI web of sciences with no restriction of language. Studies with any design (except case reports or case series) evaluating correlations of c-KIT expression with survival or outcome in patients with lung cancer will be included. The outcome measures will include all types of survival indexes, including overall survival rate and disease free survival using Kaplan-Meier analysis and hazard ratios. Study selection and data extraction will be performed by two independent researchers. Quality assessment (assessment of risk of bias) and data synthesis will be implemented using Stata software version 11.1. Results: No ethical issues are predicted. These findings will be published in a peer-reviewed journal and presented at national and international conferences. Conclusions: This systematic review protocol is registered in the PROSPERO International Prospective Register of Systematic Reviews, registration number = CRD42015023391.

육체운동에 의해 유발되는 화학물질에 대한 반응성의 변화 (Alteration in Response to Chemicals Induced by Physical Exercise)

  • 김영철
    • Toxicological Research
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    • 제18권3호
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    • pp.215-226
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    • 2002
  • Acute or repeated physical exercise affects a large number of physiological parameters including hemodynamics, respiration, pH, temperature, gastrointestinal function and biotransformation, which determine the pharmacokinetics of drugs and chemicals. The rate and the amount of a chemical reaching the active site are altered by physical exercise, which results in significant changes in pharmacolosical/toxicological activity of the chemical. This aspect of physical exercise has vast implication in therapeutics and in safety evaluation, particularly for chemicals that have a low margin of safety. However there appears to be a wide inter- and intraindividual variation in the effects of physical exercise depend-ing on the duration, intensity and type of exercise, and also on the properties of each chemical. It is suggested that more studies need to be done to determine which factor(s) plays a major role in the disposition of chemicals in human/animals performing physical exercise. Certain chemicals induce severe toxicity due to metabolic conversion to reactive intermediate metabolites. it is suggested that repeated exercise may enhance the free radical scavenging system by increasing the activity of antioxidant enzymes. This area of research remain to be explored to elucidate the interaction of exercise and chemical on the antioxidant system.

소비자 보호를 위한 선별형 샘플링 검사와 신뢰성 샘플링 검사의 최적설계에 관한 연구 (A Study on the Rectifying Inspection Plan & Life Test Sampling Plan Considering Cost)

  • 강보철;조재립
    • 품질경영학회지
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    • 제30권1호
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    • pp.74-96
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    • 2002
  • The objectives of this study is to suggest the rectifying sampling inspection plan considering quality cost. Limiting quality level(LQL) plans(also called LTPD plans) and outgoing quality(OQ) plans are considered. The Hald's linear cost model is discussed with and without a beta prior for the distribution of the fraction of nonconforming items in a lot. It is assumed that the sampling inspection is error free. We consider the design of reliability acceptance sampling plan (RASP) for failure rate level qualification at selected confidence level. The lifetime distribution of products is assumed to be exponential. MIL-STD-690C and K C 6032 standards provide this procedures. But these procedures have some questions to apply in the field. The cost of test and confidence level(1-$\beta$ risk) are the problem between supplier and user. So, we suggest that the optimal life test sampling inspection plans using simple linear cost model considering product cost, capability of environment chamber, environmental test cost, and etc. Especially, we consider a reliability of lots that contain some nonconforming items. In this case we assumed that a nonconforming item fail after environmental life test. Finally, we develope the algorithm of the optimal sampling inspection plan based on minimum costs for rectifying inspection and RASP. And computer application programs are developed So, it is shown how the desired sampling plan can be easily found.

실물옵션 가치평가모형을 이용한 국도건설사업의 경제적 가치 평가 (Economic Evaluation of National Highway Construction Projects using Real Option Pricing Models)

  • 정성윤;김지표
    • 한국도로학회논문집
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    • 제16권1호
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    • pp.75-89
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    • 2014
  • PURPOSES : This study evaluates the economic value of national highway construction projects using Real Option Pricing Models. METHODS : We identified the option premium for uncertainties associated with flexibilities according to the future's change in national highway construction projects. In order to evaluate value of future's underlying asset, we calculated the volatility of the unit price per year for benefit estimation such as VOTS, VOCS, VICS, VOPCS and VONCS that the "Transportation Facility Investment Evaluation Guidelines" presented. RESULTS : We evaluated the option premium of underlying asset through a case study of the actual national highway construction projects using ROPM. And in order to predict the changes in the option value of the future's underlying asset, we evaluated the changes of option premium for future's uncertainties by the defer of the start of construction work, the contract of project scale, and the abandon of project during pre-land compensation stages that were occurred frequently in the highway construction projects. Finally we analyzed the sensitivity of the underlying asset using volatility, risk free rate and expiration date of option. CONCLUSIONS : We concluded that a highway construction project has economic value even though static NPV had a negative(-) value because of the sum of the existing static NPV and the option premium for the future's uncertainties associated with flexibilities.

A study on the liquefaction risk in seismic design of foundations

  • Ardeshiri-Lajimi, Saeid;Yazdani, Mahmoud;Assadi-Langroudi, Arya
    • Geomechanics and Engineering
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    • 제11권6호
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    • pp.805-820
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    • 2016
  • A fully coupled non-linear effective stress response finite difference (FD) model is built to survey the counter-intuitive recent findings on the reliance of pore water pressure ratio on foundation contact pressure. Two alternative design scenarios for a benchmark problem are explored and contrasted in the light of construction emission rates using the EFFC-DFI methodology. A strain-hardening effective stress plasticity model is adopted to simulate the dynamic loading. A combination of input motions, contact pressure, initial vertical total pressure and distance to foundation centreline are employed, as model variables, to further investigate the control of permanent and variable actions on the residual pore pressure ratio. The model is verified against the Ghosh and Madabhushi high acceleration field test database. The outputs of this work are aimed to improve the current computer-aided seismic foundation design that relies on ground's packing state and consistency. The results confirm that on seismic excitation of shallow foundations, the likelihood of effective stress loss is greater in deeper depths and across free field. For the benchmark problem, adopting a shallow foundation system instead of piled foundation benefitted in a 75% less emission rate, a marked proportion of which is owed to reduced materials and haulage carbon cost.

Probabilistic service life of box culvert due to carbonation of concrete cover

  • Woo, Sang-Kyun;Chu, In-Yeop;Lee, Yun;Lee, Byung-Jae
    • Advances in concrete construction
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    • 제12권6호
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    • pp.517-525
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    • 2021
  • More underground structures are increasingly being constructed such as box culverts for electric power transmission, and the life extension of these structures is very important. It is well known that the steel embedded in concrete is usually invulnerable to corrosion because the high alkalinity of the pore solution in concrete generates a thin protective oxide layer on the surface of the steel. Recent observations in the field and experimental evidence have shown that even steel in concrete can be corroded through the carbonation reaction of cover concrete. Carbonation-induced corrosion in concrete may often occur in a high carbon dioxide environment. In this study, the risk of carbonation of underground box culverts in Korea was evaluated by measuring the car¬bonation rate and concrete cover depth in the field. Then, the carbonation-free service life for the cover depth of the steel was calcu¬lated with in situ information and Monte Carlo simulation. Additionally, an accelerated carbonation test for a cracked beam specimen was performed, and the effect of a crack on the service life of a box culvert was numerically investigated with Monte Carlo simulation based on experimental results.

A preliminary study on real-time Rn/Tn discriminative detection using air-flow delay in two ion chambers in series

  • Sopan Das ;Junhyeok Kim ;Jaehyun Park ;Hojong Chang;Gyuseong Cho
    • Nuclear Engineering and Technology
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    • 제54권12호
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    • pp.4644-4651
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    • 2022
  • Due to its short half-life, thoron gas has been assumed to have negligible health hazards on humans compared to radon. But, one of the decay products with a long half-life can make it to be transported to a long distance and to cause a severe internal dose through respiration. Since most commercial radon detectors can not discriminate thoron signals from radon signals, it is very common to overestimate radon doses which in turn result in biased estimation of lung cancer risk in epidemiological studies. Though some methods had been suggested to measure thoron and radon separately, they could not be used for real-time measurement because of CR-39 or LR-115. In this study, an effective method was suggested to measure radon and thoron separately from the free air. It was observed that the activity of thoron decreases exponentially due to delay time caused by a long pipe between two chambers. Therefore from two ion chambers apart in time, it was demonstrated that thoron and radon could be measured separately and simultaneously. We also developed a collimated alpha source and with this source and an SBD, we could convert the ion chamber reading to count rate in cps.

The location of locoregional recurrence in pathologic T3N0, non-irradiated lower rectal cancer

  • Kim, Mi Sun;Keum, Ki Chang;Rhee, Woo Joong;Kim, Hyunju;Kim, Minji;Choi, Seohee;Nam, Ki Chang;Koom, Woong Sub
    • Radiation Oncology Journal
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    • 제31권2호
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    • pp.97-103
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    • 2013
  • Purpose: To investigate the patterns of locoregional recurrence of pathologic T3N0 (pT3N0) lower rectal cancer omitting postoperative radiotherapy (RT) and explore the potential of modification of a RT field. Materials and Methods: From Jan 2003 to Nov 2011, 35 patients omitting preoperative or postoperative RT for pT3N0 lower rectal cancer were included. We defined the lower rectal cancer as the tumor with the inferior margin located below the virtual line-a convergent level between rectal wall and levator ani muscle. All patients had radiologic examinations for recurrence evaluation during the follow-up duration. Results: The median follow-up duration was 66.4 months (range, 1.4 to 126.1 months). Eight (22.9%) of the 35 patients had recurrence. Three (8.6%) was local recurrence (LR) only, 3 (8.6%) was distant metastasis (DM) only, and 2 (5.7%) was LR with DM. All LR were located at primary tumor sites. The overall survival rate, LR-free survival rate, and DM-free survival rate at 5 years was 79.8%, 83%, and 87%, respectively. All LR developed from tumors over 5 cm. However, there was no statistical significance (p = 0.065). There was no other risk factor for LR. Conclusion: Even though the patients included in this study had pathologically favorable pT3N0 rectal cancer, LR developed in 14.3% of patients. Most of the LR was located at primary tumor sites prior to surgery. Based on these findings, it might seem reasonable to consider postoperative RT with a smaller radiation field to the primary tumor site rather than the conventional whole pelvic irradiation.

골육종에서 수술 전 항암 약물치료가 생존에 미치는 영향 (Effect of Preoperative Chemotherapy on Survival in High-grade Localized Osteosarcoma of the Extremity)

  • 최은석;한일규;조환성;김한수
    • 대한골관절종양학회지
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    • 제18권2호
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    • pp.59-65
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    • 2012
  • 목적: 본 연구는 수술 전 항암 약물 치료가 전이가 없는 골육종 환자의 생존율과 전이에 미치는 영향에 대해 알아보고자 하였다. 대상 및 방법: 1984년부터 2010년까지 사지에 발생한, 전이가 없는 원발성 골육종으로 수술적 절제술과 수술 후 항암 약물 치료를 시행한 30세 미만의 환자 225명을 후향적으로 분석하였다. 평균 연령은 14.4세, 평균 추시기간은 9.1년이었다. 수술 후에만 항암 약물 치료를 시행한 군과 수술 전, 후 약물 치료를 시행했던 두군의 임상적 특성과 생존율을 비교하였다. 결과: 전체 225예 중 수술 후 약물 치료 군은 32예, 수술 전후 약물 치료 군은 193예였다. 수술 후 약물 치료 군은 절단 수술과(p<0.001), 전이의 빈도가 유의하게(p=0.004) 높았으며, 전이 발생시기도 빨랐다. 수술 후 약물 치료 군에서는 5년 생존율 51%로 수술 전후 약물 치료 군의 84%보다 낮았다(p=0.001). 국소재발은 유의한 차이가 없었다. 결론: 사지에 발생한 골육종 환자에서 수술 전 항암 약물 치료는 전이의 억제와 생존율 향상에 도움이 된다.

자궁경부암의 수술 후 방사선치료 (Adjuvant Postoperative Radiation Therapy for Carcinoma of the Uterine Cervix)

  • 이경자;문혜성;김승철;김종일;안정자
    • Radiation Oncology Journal
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    • 제21권3호
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    • pp.199-206
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    • 2003
  • 목적: 자궁경부암에서 수술 후 위험인자가 있는 환자에 방사선치료 후 생존율, 국소 제어율과 예후인자를 후향적으로 분석하여 수술 후 방사선치료의 효과를 알고자 한다. 대상 및 방법: 1986년 3월부터 1998년 12월까지 자궁경부암 FIGO 병기 IB-IIB로 자궁적출술 후 방사선치료를 받은 58명을 대상으로 국소 제어율, 5년 무병생존율과 생존율에 미치는 예후인자를 후향적으로 분석하였다. 수술 후 방사선치료의 적응증은 병리학적으로 림프절에 전이된 경우, 암이 수술절제연이나, 자궁주위조직 혹은 자궁체부에 침범하였거나, 림프혈관강에 침범된 경우, 자궁기질의 1/2 이상 깊이 침윤된 경우와 단순 자궁적출술 후 암으로 진단받은 환자로 하였다. 수술 후 방사선치료는 모든 환자에서 골반강에 외부조사를 시행하였으며 5명은 외부조사와 강내조사를 병용하였다. 외부조사는 6 MV x-선을 이용하여 매일 180 cGy를 4문으로 조사하였으며 총 방사선량은 $4400\~5040$ cGy (중앙값: 5040 cGy)이었다. 강내조사는 외부조사 후 2주에 Cs-137를 이용하여 저선량률로 질 표면에서 5 mm 깊이에 $4488\~4932$ cGy (중앙값: 4500 cGy)를 시행하였다. 추적기간은 15개월에서 108개월로 중앙값은 44개월 이었다. 결과: 전체환자의 5년 무병생존율은 $94\%$, 국소 제어율은 $98\%$,이었으며 원격 전이율은 $5\%$이었다. 병기에 따른 5년 무병생존율은 $IB\;97.1\%,\;IIA\;100\%,\;IIB\;68.9\%$(p=0.0145)이었다. 질 절제연에 암의 침범이 없는 경우 5년 무병생존율이 $97.8\%$, 있는 경우 $60\%$, (P=0.0002)이었으며, 자궁주위조직에 암이 침범이 없는 경우의 5년 무병 생존율은 $97.8\%$이었고, 있는 경우는 $33.3\%$이었다(p=0.0001). 다변량 분석에 의하면 자궁주위조직의 침범만이 통계학적으로 의의있는 예후인자이었다. 치료 후 만성합병증은 3명($5\%$,)에서 RTOG grade 2의 방광염, 1명에서 grade 2의 직장염과 1명에서 하지에 림프부종이 나타났다. 결론: 조기 자궁경부암 환자에 단순 자궁적출술을 시행하였거나, 근치적 자궁적출술 후 병리학적으로 재발 위험 인자가 있는 환자에 수술 후 방사선치료를 시행하여 심각한 부작용 없이 비교적 높은 국소 제어율과 생존율을 얻을 수 있었다. 생존율에 영향을 미치는 예후인자는 병리학적으로 암이 자궁주위조직에 침범된 것으로 예후가 불량하였다. 수술 후 방사선치료의 실패원인과 예후인자를 분석한 본 후향적 연구결과를 토대로 앞으로 방사선치료와 항암화학요법을 병용하여 보다 적극적이고 전향적인 연구를 시도하는데 이정표로 이용할 수 있다고 생각한다.