• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.1
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• pp.83-89
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• 2011

A design plan was proposed for determining combustor configuration of regenerative- cooled liquid rocket engine in the process of preliminary design. Rocket performance and regenerative cooling results were calculated using the properties of combustion gas estimated in CEA. For required thrust, chamber pressure, atmosphere pressure and propellant mixture ratio the mass flow rate of propellants and combustor performance were predicted by one-dimensional and experimental correlations. Finally, determinable plan for the contour of combustor were presented through Rao nozzle design method.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.3
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• pp.1-7
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• 2014

A set of preliminary design parameters for the bipropellant rocket engine using liquid methane-fuel as green propellant were derived through a theoretical performance analysis. Chemical equilibrium analysis utilizing CEA was conducted for the prediction of combustion performance: combustion characteristics according to the O/F ratio and chamber pressure variation were investigated. For a determination of chamber-characteristic length, the vaporization time of fuel-droplet with various performance parameters was calculated by applying Spalding's 1-D droplet vaporization model. Finally, the preliminary design specification of methane-bipropellant rocket engine, which is to be performance-tested under the ground firing condition, was proposed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.37-42
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• 2010

A design plan was proposed for determining combustor configuration of regenerative- cooled liquid rocket engine in the process of preliminary design. Rocket performance and regenerative cooling results were calculated using the properties of combustion gas estimated in CEA. For required thrust, chamber pressure, atmosphere pressure and propellant mixture ratio the mass flow rate of propellants and combustor performance were predicted using one-dimensional and experimental equations. Finally, determinable plan for contour of combustor were presented through Rao nozzle design method.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.7
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• pp.3015-3021
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• 2015

Background: Colorectal cancer (CRC) is a major cause of mortality in developed countries, and it is the third most frequent malignancy in Turkey. There are many biological, genetic, molecular, and tissue-derived prognostic factors for CRCs. In this study, we evaluated prognostic factors in patients who were metastatic at diagnosis or progressed to metastatic disease during follow-up. Patients and Methods: This study included 116 patients with malignancies either in the colon or rectum. Of these, 65 had metastatic disease at diagnosis, and 51 progressed to metastatic disease during the course of the disease. The parameters evaluated were age, gender, comorbidity, performance status and stage of the disease at the beginning, localization, history of surgery, chemotherapy regimen, response to first-line treatment, K-RAS status, site and number of metastases, expression of tumor predictors (CEA, CA19-9), and survival times. A multivariate analysis conducted with factors that considered statistically significant in the univariate analysis. Findings: Median age was 56 (32-82) years and the male/female ratio was 80/36. Eleven patients were at stage II, 40 at stage III, and 65 at stage IV at diagnosis. Twenty three patients had tumor in the right colon, 48 in the left colon, and 45 in the rectum. Ninety seven patients were operated, and 27 had surgical metastasectomy. Ninety three patients received targeted therapy. At the end of follow-up, 61 patients had died, and 55 survived. Metastatic period survival times were longer in the adjuvant group, but the difference did not reach the level of statistical significance (adjuvant group: median 29 months, metastatic group: median 22 months; p=0.285). In the adjuvant group before the metastatic first-line therapy, CEA and CA 19-9 levels were significiantly lower compared to the metastatic group (p<0.005). We also found that patients with elevated tumor predictor (CEA, CA 19-9) levels before the first-line therapy had significiantly poorer prognosis and shorter survival time. Survival was significiantly better with the patients who were younger than 65 years of age, had better initial performance status, a history of primary surgery and metastatectomy, and single site of metastasis. Those who benefitted from the first-line therapy were K-RAS wild type and whose tumor markers (CEA, CA 19-9) were not elevated before the first line therapy. Conclusions: Among the patients with metastatic CRC, those who benefited from first-line therapy, had history of metastasectomy, were K-RAS wild type and had low CA 19-9 levels before the first-line therapy, showed better prognosis independent of other factors.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.17
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• pp.7327-7331
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• 2014

Background: We had previously showed that the neutrophil lymphocyte ratio (NLR), ${\gamma}$-glutamyl transpeptidase (GGT) and carcinoembryonic antigen (CEA) are prognostic factors for metastatic colorectal cancer (mCRC) patients. In this study we developed a prognostic model based on these three indices. Materials and Methods: A total of 243 patients who were initially diagnosed as mCRC between 2005 and 2010 in the Sun Yat-sen University Cancer Center were studied. The endpoint was overall survival (OS). Results: NLR>3, elevated GGT and elevated CEA were confirmed as independent risk factors which could predict poor prognosis. Patients could be divided into three groups according to the number of risk factors they had. Those with two or three were defined as the high risk group, individuals with one risk factor as the modest risk group and patients without risk factor as the low risk group. The OS values for these three groups were 16.2 months (2.80~68.8), 24.2 months (4.07~79.0), and 37.2 months (12.6~87.8), respectively (p<0.001). Conclusions: We developed a simple but useful model based on NLR, GGT and CEA to provide prognostic information to clinical practice in highly selected mCRC patients. Further prospective and multi-center studies are warranted to test our model.

• Journal of Gastric Cancer
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• v.14 no.3
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• pp.164-172
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• 2014

Purpose: To evaluate the incidence, clinicopathological characteristics, treatment outcomes, prognostic factors, and survival of gastric cancer patients with bone metastases. Materials and Methods: Of 4,617 gastric cancer patients who were treated between 2001 and 2013, 176 patients with bone metastases were analyzed. Results: The incidence of bone metastasis was 3.8%. The most common histopathological subtype was adenocarcinoma (79%) with poor differentiation (60.8%). The median interval from the diagnosis to bone metastasis was 11 months. The median survival time after bone metastasis was 5.4 months. Factors that were associated with longer median survival times included the following: isolated bone metastasis (P=0.004), well-differentiated tumors (P=0.002), palliative chemotherapy (P=0.003), zoledronic acid treatment (P<0.001), no smoking history (P=0.007), and no metastatic gastric cancer at the time of diagnosis (P=0.01). On the other hand, high levels of lactate dehydrogenase (LDH) (hazard ratio [HR]: 1.86; P=0.015), carcinoembryonic antigen (CEA) (HR: 2.04; P=0.002), and carbohydrate antigen (CA) 19-9 (HR: 2.94; P<0.001) were associated with shorter survival times. In multivariate analysis, receiving zoledronic acid (P<0.001) and performance status (P=0.013) were independent prognostic factors. Conclusions: Smoking history, poor performance status, poorly differentiated adenocarcinoma, and high levels of LDH, CEA, and CA 19-9 were shown to be poor prognostic factors, while receiving chemotherapy and zoledronic acid were associated with prolonged survival in gastric cancer patients with bone metastases.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.6573-6578
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• 2013

Background: The goal of this retrospective study was to evaluate patient characteristics, treatment modalities and prognostic factors in Turkish patients with pancreatic cancer. Materials and Methods: Between January 1997 and December 2012, 64 patients who presented to the Department of Radiation Oncology, Karadeniz Technical University, Faculty of Medicine with a diagnosis of pancreatic cancer were evaluated. The E/K ratio of the cases was 2.4/1 and the median age was 59.6 (32-80) years, respectively. Some 11 cases (18%) were stage 1, 21 (34.4%) were stage 2, 10 (16.4%) were stage 3, and 19 (31.1%) were metastatic. Results: The mean follow-up time was 15.7 months (0.7-117.5) and loco-regional recurrence was noted in 11 (40.7%) who underwent surgery while metastases were observed in 41 patients (66.1%). The median overall survival (OS) was 11.2 months and the 1, 3 and 5-year OS rates were 41.7%, 9.9% and 7.9% respectively. The median disease-free survival (DFS) was 5.2 month and the1, 2 and 5 year DFS were 22.6%, 7.6% and 3.8% respectively. On univariate analysis, prognostic factors affecting OS included status of the operation (p<0.001), tumor stage (p=0.008), ECOG performance status (p=0.005) and CEA level (p=0.017).On multivariate analysis, prognostic factors affecting survival included status of the operation (p=0.033) and age (p= 0.023). Conclusions: In the current study, age and operation status were independent prognostic factors for overall survival with pancreatic patients. Thus, the patients early diagnosis and treatment ars essential. However, prospective studies with more patients are needed for confirmation.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.2
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• pp.9-15
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• 2013

An effect of a spiral turbulent ring, so-called Shchelkin spiral, on a detonation performance was studied experimentally for acetylene and oxygen mixture. A couple of dynamic pressure transducers were used to calculate a detonation wave velocity by a time difference between two pressure peaks. In addition, impulse was measured by a load cell and the impulse was used to analyze the spiral effect on the detonation performance. A CFD analysis was adopted to calculate mass flow rates of the propellants and the minimum filling time. The maximum velocity and pressure were measured at the equivalence ratio of 2.4, and the measured values showed similar trend to C-J conditions calculated from CEA. For the shorter chamber with the short spiral, the maximum detonation velocity was appeared. In contrast, the longer chamber without the spiral showed the maximum thrust performance.

• Journal of Yeungnam Medical Science
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• v.39 no.2
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• pp.124-132
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• 2022

Background: Despite recent advances in first-line chemotherapy for advanced pancreatic cancer, standard treatment after the failure of initial chemotherapy has not been established. Hence, we aimed to retrospectively analyze the clinical characteristics and outcomes of second-line chemotherapy in patients with advanced pancreatic cancer. Methods: We reviewed the clinical data of patients with advanced pancreatic cancer who underwent palliative chemotherapy at Kosin University Gospel Hospital between January 2013 and October 2020. Results: Among 366 patients with advanced pancreatic cancer who had received palliative chemotherapy, 104 (28.4%) underwent at least one cycle of second-line chemotherapy. The median age of the patients at the time of initiating second-line treatment was 62 years (interquartile range, 57-62 years), and 58.7% (61 patients) of them were male. The common second-line chemotherapy regimens were 5-fluorouracil (FU) plus leucovorin, irinotecan, and oxaliplatin (33 patients, 31.7%); gemcitabine/nab-paclitaxel (29, 27.9%), gemcitabine±erlotinib (13, 12.5%); and oxaliplatin and 5-FU/leucovorin (12, 11.5%). The median overall survival (OS) and progression-free survival were 6.4 months (95% confidence interval [CI], 4.5-8.6 months) and 4.5 months (95% CI, 2.7-6.3 months), respectively. In a multivariate analysis, poor performance status (PS) (hazard ratio [HR], 2.247; p=0.021), metastatic disease (HR, 2.745; p=0.011), and elevated carcinoembryonic antigen (CEA) levels (HR, 1.939; p=0.030) at the beginning of second-line chemotherapy were associated with poor OS. Conclusion: The survival outcome of second-line chemotherapy for advanced pancreatic cancer remains poor. However, PS, disease extent (locally advanced or metastatic), and CEA level may help determine patients who could benefit from second-line treatment.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.5
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• pp.429-435
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• 2009

Purpose: The purpose of this study was to assess the prognostic value of preoperative FDG-PET in colorectal cancer (CRC) patients with hepatic metastasis (HM). Materials and Methods: 24 CRC patients (M:F=14:10; age, $63{\pm}10$ yrs) with HM who had undergone preoperative FDG PET were included. Cure-intent surgery was performed in all the patients and HMs were controlled using resection (n=13), radio-frequency ablation (RFA) (n=7), and resection plus RFA (n=4). Potential prognostic markers tested were maxSUV of primary tumor, maxSUV of HM, maxSUV ratio of HM over primary tumor (M/P ratio), histologic grade, CEA level, venous/lymphatic/nerve invasion, T stage, N stage, no. of HM, no. of lymph node metastasis, and treatment modality of HM. Results: 14 CRC patients developed a recurrence with a median follow-up duration of 244 days, whereas 10 patients did not develop recurrence with a median follow-up duration of 504 days. M/P ratios but other potential prognostic markers were significantly higher in the recurrent patients ($0.72{\pm}0.14$) than recurrence-free patients ($0.54{\pm}0.23$) (p=0.038). M/P ratio only was found to predict recurrence by Cox multivariate analysis (hazard ratio 37.7, 95% confidence interval 2.01-706.1, p=0.016). The 11 patients with lower M/P ratio of <0.61 had significantly better disease-free survival rate than the 13 patients with higher M/P ratio (${\geq}0.61$) (p=0.026). Conclusion: maxSUV ratio of HM over primary tumor (M/P ratio) may be useful for prognosis prediction of CRC patients with HM. Higher FDG uptake of HM than that of primary tumor may indicate a more advanced status in stage IV CRC.