• Development and Reproduction
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• v.17 no.4
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• pp.337-343
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• 2013

Post-thawed larval rearing in Pacific oyster Crassostrea gigas was performed to investigate the survival rate with time course in three kinds of larvae cryopreserved. The highest survival rate and larval activity index (LAI) of post-thawed larvae were obtained from the permeation in 0.2 M sucrose and 2.0 M ethylene glycol (EG) at $-1^{\circ}C/min$ in freezing speed showing the survival rates just after thawing of 63.8% in trochophore, 84.1% in D-shaped veliger and 56.3% in early umbo veliger. In post-thawed larval rearing with food supply, the larvae lasted their lives until 24 hours in trochophore, 75 hours in D-shaped veliger and 57 hours in early umbo veliger. The results suggested that each larval stage post-thawed revealed no more further development to subsequent respective stage.

• Communications for Statistical Applications and Methods
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• v.15 no.5
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• pp.727-735
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• 2008

Consider a clinical trial in which the main end-point is survival. Suppose after the start of the study an intermediate event occurs which may be influenced by a covariate(or treatment). In many clinical studies the occurrence of an intermediate event may change the survival distribution. This investigation develops two-stage model which, in the first stage, models the effect of covariate on the intermediate event and models the relationship between survival time and covariate as well as the intermediate event. In this paper, the two-stage model is presented in order to model intermediate event and a test based on this model is also provided. A numerical simulations are carried out to evaluate its overall significance level.

• Journal of the Korean Mathematical Society
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• v.50 no.1
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• pp.111-125
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• 2013

In this paper, we consider a continuous time risk model involving two types of dependent claims, namely main claims and by-claims. The by-claim is induced by the main claim and the occurrence of by-claim may be delayed depending on associated main claim amount. Using Rouch$\acute{e}$'s theorem, we first derive the closed-form solution for the Laplace transform of the survival probability in the dependent risk model from an integro-differential equations system. Then, using the Laplace transform, we derive a defective renewal equation satisfied by the survival probability. For the exponential claim sizes, we present the explicit formula for the survival probability. We also illustrate the influence of the model parameters in the dependent risk model on the survival probability by numerical examples.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.12
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• pp.7117-7120
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• 2013

Background: This study hypothesized living in a poor neighborhood decreased the cause specific survival in individuals suffering from carcinoid carcinomas. Surveillance, Epidemiology and End Results (SEER) carcinoid carcinoma data were used to identify potential socioeconomic disparities in outcome. Materials and Methods: This study analyzed socioeconomic, staging and treatment factors available in the SEER database for carcinoid carcinomas. The Kaplan-Meier method was used to analyze time to events and the Kolmogorov-Smirnov test to compare survival curves. The Cox proportional hazard method was employed for multivariate analysis. Areas under the receiver operating characteristic curves (ROCs) were computed to screen the predictors for further analysis. Results: There were 38,546 patients diagnosed from 1973 to 2009 included in this study. The mean follow up time (S.D.) was 68.1 (70.7) months. SEER stage was the most predictive factor of outcome (ROC area of 0.79). 16.4% of patients were un-staged. Race/ethnicity, rural urban residence and county level family income were significant predictors of cause specific survival on multivariate analysis, these accounting for about 5% of the difference in actuarial cause specific survival at 20 years of follow up. Conclusions: This study found poorer cause specific survival of carcinoid carcinomas of individuals living in poor and rural neighborhoods.

• The Pure and Applied Mathematics
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• v.2 no.2
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• pp.83-89
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• 1995

A Bayes estimator of the survival distribution function due to Susarla and Van Ryzin(1976) is used to estimate the mth moment of a survival time on the basis of censored observations in a random censorship model. Asymptotic normality of the estimator is proved using the functional version of the delta method.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.9
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• pp.4387-4391
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• 2012

Background: Lung carcinoma is the leading cause of cancer mortality worldwide. Although the 5-year survival rate nearly tripled from 5-15% over the last 25 years, the estimated number of deaths still exceeds 1.3 million annually. The overall 5-year survival of lung cancer is only 10% in Europe and 15% in the United States. The aim of the current study was to determine the long-term survival and the effect of certain prognostic factors on survival of patients with lung cancer in Yazd city, Iran. Methods: In this cross-sectional descriptive study, we retrospectively reviewed hospital records and follow-up data of 148 patients with histological proven lung cancer using the cancer data registered between 1998 and 2005 in the pathology department of Shahid Sadoughi educational hospital, Yazd, Iran. Data were extracted from patient documents that included sex, age, clinical manifestations, histopathological report of the tumor and type of treatment given. Results: Overall survival time in all patients was 8.5 months after diagnosis and there was no significant difference in survival according to sex (p=0.958). Histological analysis revealed that squamous cell carcinoma was the most common histologic type (35%). Kaplan-Meier statistical methods estimated the average survival time for SCC to be better (22.6 months) in comparison with the other types of histology (all of them below 10 months). There was a trend towards significance between type of histology and duration of survival (p=0.08). Conclusion: It is reasonable to expect that early lung cancer detection, and appropriated treatment, may improve surgical morbidity and mortality. Low survival of lung cancer in our center patients show our shortages in screening programs for early diagnosis. Designing studies with larger sample size that take some other variables like staging of patients is now necessary.

• Journal of the Korean Data and Information Science Society
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• v.21 no.4
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• pp.747-756
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• 2010

With the recent recession, studies on the economy are actively being conducted throughout the industry. Based on the Small Business data registered in the Credit Guarantee Fund, we estimated the survival probability in the context of the survival analysis. We also analyzed the survival time for the construction and the other industries which are distinguished depending on the types of business and assets in the Small Business. The survival probability was estimated by using the life-table and the difference between the survival probabilities for the different types of business was described via the method of the Log-rank test and the Wilcoxon test. We found that the small business with over one billion asset has the highest survival probability and that with less than 1000 million asset showed the similar survival probability. In terms of types of business Wholesale and Retail trade industry and Services were relatively high in the survival probability than Light, Heavy, and the construction industries. Especially the construction industry showed the lowest survival probability. Most of the Small Business tend to increase in the hazard rate over time.

• Progress in Superconductivity and Cryogenics
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• v.15 no.4
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• pp.10-14
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• 2013

We have clearly investigated with respect to the survival of the insulator at cryogenic temperature under the electrical stress. The breakdown and voltage-time characteristics of turn-to-turn models for point contact geometry and surface contact geometry using copper multi wrapped with polyimide film for an HTS transformer were investigated under AC and impulse voltage at 77 K. Polyimide film (Kapton) 0.025 mm thick is used for multi wrapping of the electrode. As expected, the breakdown voltages for the surface contact geometry are lower than that of the point contact geometry, because the contact area of the surface contact geometry is lager than that of the point contact geometry. The time to breakdown t50 decreases as the applied voltage is increased, and the lifetime indices increase slightly as the number of layers is increased. The electric field amplitude at the position where breakdown occurs is about 80 % of the maximum electric field value. The relationship between survival probability and the electrical stress at cryogenic temperature was evident.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.9
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• pp.4281-4284
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• 2012

Background: Osteosarcoma is the most common bone cancer in children, responsible for a high rate of amputation and death. This is the first long-term, population-based, epidemiologic and survival study in Thailand. Objective: To study the incidence and survival rates of pediatric osteosarcoma in Khon Kaen. Method: Childhood osteosarcoma cases (0-19 years) diagnosed between 1985-2010 were reviewed. The data were retrieved from the population-based data set of the Khon Kaen Cancer Registry and medical records from Srinagarind Hospital, Faculty of Medicine, Khon Kaen University. All cases were censored until the end of April 2012. The age-standardized incidence rate (ASR) was calculated using the standard method. Survival experience was analyzed using the standard survival function (STATA 9.0) and presented with a Kaplan-Meier curve. Results: 58 cases were enrolled. The overall ASR was 14.1 per million. Males and females were equally affected. The peak incidence was for 15-19 year-olds in both sexes (ASR=10.4 per million in males and 8.5 in females). The 5-year overall survival rate was 27.6% (95% CI: 15.8-40.8%). The median survival time was 1.6 years (95% CI: 1.2-2.1). In a subgroup analysis, the patients who received only chemotherapy survived longer (5-year survival 45.7%, median survival time 4.1 years, p=0.12). Conclusion: The incidence rate for childhood osteosarcoma was slightly less than those reported for Western countries. The survival rate was also lower than reports from developed countries. Further evaluation of the treatment protocol and risk factor stratification is needed.

• Journal of Gastric Cancer
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• v.11 no.1
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• pp.31-37
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• 2011

Purpose: We performed this study to evaluate the clinical presentation as well as the proper surgical intervention for ovarian metastasis from gastric cancers and these tumors were identified during postoperative follow-up. This will help establish the optimal strategy for improving the survival of patients with this entity. Materials and Methods: 22 patients (3.2%) with ovarian metastasis were noted when performing a retrospective chart review of (693) females patients who had undergone a resection for gastric cancer between 1981 and 2008. The covariates used for the survival analysis were the patient age at the time of ovarian relapse, the size of the tumor, the initial TNM stage of the gastric cancer, the interval to metastasis and the presence of gross residual disease after treatment for Krukenberg tumor. The cumulative survival curves for the patient groups were calculated with the Kaplan-Meier method and they were compared by means of the Log-Rank test. Results: The average age of the patients was 48.6 years (range: 24 to 78 years) and the average survival time of the 22 patients was 18.8 months (the estimated 3-year survival rate was 15.8%) with a range of 2 to 59 months after the diagnosis of Krukenberg tumor. The survival rate for patients without gross residual disease was longer than that of the patients with gross residual disease (P=0.0003). In contrast, patient age, the size of ovarian tumor, the initial stage of gastric adenocarcinoma, the interval to metastasis and adjuvant chemotherapy were not prognostic indicators for survival after the development of ovarian metastasis. Conclusions: Early diagnosis and complete resection are the only possible hope to improve survival. As the 3-year survival rate after resection of Krukenberg tumor is 15.8%, it seems worthwhile to consider performing tumorectomy as the second cytoreduction.