• Journal of Elementary Mathematics Education in Korea
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• v.20 no.3
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• pp.431-456
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• 2016

The purpose of this study is to investigate the appropriate time of introduction and the usage of the number line, in order to suggest the right point of learning the number concept to the elementary school students. For the efficient achievement of this purpose, we investigated the mathematical models for constructing the number concept such as number line, empty number line and double number line, counting and development of number concept. Then, we conducted case study on the time of introduction and the usage of the number line. Finally, we analyzed the result. First, there is need for adjustment to conduct the introduction of the number line from the second year of elementary school, so to help the students understand the continuing number concept through the understanding on the metaphorical concept of the number line. Second, there is the need of positive introduction and the use on the mathematical models; empty number line which helps to draw various thinking strategy visually through the process of operations such as addition and subtraction; the division into equal part and division by equal part in which multiplicative comparative situation or division takes place; the double number line which helps to understand the rate or proportional distribution. Finally, when adopting the number line, the empty number line, or the double number line, we suggested the necessity of learning about elaborate guidance and the usage in order to fully understand the metaphorical concept of the number line.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.1
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• pp.33-40
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• 2014

Reliability analysis of jacket type offshore wind turbine (OWT) support structure under extreme ocean environmental loads was performed. Limit state function (LSF) of OWF support structure is defined by using structural dynamic response at mud-line. Then, the dynamic response is expressed as the static response multiplied by dynamic response factor (DRF). Probabilistic distribution of DRF is found from response time history under design significant wave load. Band limited beta distribution is used for internal friction angle of ground soil. Wind load is obtained in the form of thrust force from commercial code called GH_Bladed and then, applied to tower hub as random load. In a numerical example, the response surface method (RSM) is used to express LSF of jacket type support structure for 5MW OWF. Reliability index is found using first order reliability method (FORM).

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.3
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• pp.1357-1362
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• 2016

Metastatic gestational trophoblastic neoplasia (GTN) is an uncommon cancer. The principal treatment consists of chemotherapy with or without surgery or radiotherapy. We here retrospectively reviewed the outcomes of metastatic GTN treated at our institute between January, 1999 and December, 2013. Sixty-three patients met the criteria. The median age was 30.0 years and almost 90% were referral cases. Nearly 40% of the studied patients presented with vaginal bleeding while 22.2% were asymptomatic. The most common antecedent pregnancy was hydatidiform mole (57.1%) followed by term pregnancy (20.6%). The median interval time from antecedent pregnancy to the development of GTN was three months and the median pretreatment B-hCG was 58,274 mIU/ml. Stage III (74.6%) was the most common staging followed by stage IV (20.6%) and stage II (4.8%). The most frequent surgery was hysterectomy (31.7%). Thoracotomy and craniotomy were performed in three and two patients, respectively. The most common first line chemotherapy regimen was methotrexate and folinic acid (36.5%) followed by EMA (etoposide, methotrexate, actinomycin D) (34.9%), EMACO (etoposide, methotrexate, actinomycin D, cyclophosphamide, vincristine) (17.5%) with the remission rate of 66.7%. Nearly one-third of the patients were given a subsequent chemotherapy regimen after failure with the first line therapy and showed a final response rate of 73.0%. However, in stage IV, the response to first line treatment was only 38.5%. In conclusion, the outcomes of metastatic GTN were poor especially with the higher stages.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.17
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• pp.7453-7457
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• 2014

Objective: To observe the efficacy and toxicity of nanoparticle albumin bound paclitaxel (nab-paclitaxel) plus platinum agent (cisplatin or carboplatin) as first line treatment for stage III/IV squamous non-small-cell lung cancer (NSCLC). Methods: Forty chemotherapy naive patients with stage III/IV squamous NSCLC received nab-paclitaxel $125mg/m^2$ on day 1 and day 8, cisplatin $75mg/m^2$ on day 1, carboplatin area under the concentration-time curve of 5 (AUC=5) on day 1. One cycle of treatment was 3 weeks, and at least two were completed in each case. Results: Of the 40 patients who participated in the study, 25 achieved partial responses (PR), 12 reached a stage of stable disease (SD), and 3 suffered progressive disease (PD). The overall response rate (ORR) was 62.5% and the disease control rate (DCR) was 92.5%. Of the 20 patients without surgery or radiotherapy, 10 achieved PR, 7 reached a stage of SD, and 3 PD. The ORR was 50.0% and the DCR was 85.0%. The median progression-free survival time (PFS) of patients without surgery or radiotherapy was 5.0 months. Of the 20 patients receiving surgery or radiotherapy, 15 had PR and 5 p had SD, with an ORR of 75.0% and a DCR of 85.0%. Specifically, the DDP arm demonstrated a significantly higher ORR than the CBP arm (100%vs 54.5%, P<0.05). Common treatment related adverse events were myelosuppression, gastrointestinal response, baldness and neurotoxicity, most of which were grade 1 to 2. Conclusion: Nab-paclitaxel plus platinum agent (cisplatin or carboplatin) is effective as a first-line chemotheraphy for stage III/IV squamous NSCLC, and its adverse effects are tolerable.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.1
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• pp.321-326
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• 2015

Background: The aim of this study was to explore the prognostic role of metabolic response to chemotherapy, determined by FDG-PET, in patients with metastatic non-small-cell lung cancer (NSCLC). Materials and Methods: Thirty patients with metastatic NSCLC were analyzed for prognostic factors related to overall survival (OS) and progression free survival (PFS). Disease evaluation was conducted with FDG-PET/CT and contrast-enhanced CT prior to and at the end of first-line chemotherapy. Response evaluation of 19 of 30 patients was also performed after 2-3 cycles of chemotherapy. Morphological and metabolic responses were assessed according to RECIST and PERCIST, respectively. Results: The median OS and PFS were 11 months and 6.2 months, respectively. At the end of first-line chemotherapy, 10 patients achieved metabolic and anatomic responses. Of the 19 patients who had an interim response analysis after 2-3 cycles of chemotherapy, 3 achieved an anatomic response, while 9 achieved a metabolic response. In univariate analyses, favorable prognostic factors for OS were number of cycles of first-line chemotherapy, and achieving a response to chemotherapy at completion of therapy according to the PERCIST and RECIST. The OS of patients with a metabolic response after 2-3 cycles of chemotherapy was also significantly extended. Anatomic response at interim analysis did not predict OS, probably due to few patients with anatomic response. In multivariate analyses, metabolic response after completion of therapy was an independent prognostic factor for OS. Conclusions: Metabolic response is at least as effective as anatomic response in predicting survival. Metabolic response may be an earlier predictive factor for treatment response and OS in NSCLC patients.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.8
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• pp.3111-3116
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• 2015

Background: This study was designed to investigate the value of CEA and CA199 in predicting the treatment response to palliative chemotherapy for advanced gastric cancer. Materials and Methods: We studied 189 patients with advanced gastric cancer who received first-line chemotherapy, measured the serum CEA and CA199 levels, used RECIST1.1 as the gold standard and analyzed the value of CEA and CA199 levels changes in predicting the treatment efficacy of chemotherapy. Results: Among the 189 patients, 80 and 94 cases had increases of baseline CEA (${\geq}5ng/ml$) and CA199 levels (${\geq}27U/ml$), respectively. After two cycles of chemotherapy, 42.9% patients showed partial remission, 33.3% stable disease, and 23.8% progressive disease. The area under the ROC curve (AUC) for CEA and CA199 reduction in predicting effective chemotherapy were 0.828 (95%CI 0.740-0.916) and 0.897 (95%CI 0.832-0.961). The AUCs for CEA and CA199 increase in predicting progression after chemotherapy were 0.923 (95%CI 0.865-0.980) and 0.896 (95%CI 0.834-0.959), respectively. Patients who exhibited a CEA decline ${\geq}24%$ and a CA199 decline ${\geq}29%$ had significantly longer PFS (log rank p=0.001, p<0.001). With the exception of patients who presented with abnormal levels after chemotherapy, changes of CEA and CA199 levels had limited value for evaluating the chemotherapy efficacy in patients with normal baseline tumor markers. Conclusions: Changes in serum CEA and CA199 levels can accurately predict the efficacy of first-line chemotherapy in advanced gastric cancer. Patients with levels decreasing beyond the optimal critical values after chemotherapy have longer PFS.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.7
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• pp.3277-3280
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• 2016

Background: Gastric cancer is considered the fourth most common cancer and second most common cause of cancer-related mortalities worldwide. Gastric cancer develops more frequently among elderly. The oxaliplatin/5FU/leucovorin (FOLFOX) regimen has shown a notable activity against gastric cancer. Aim: To evaluate the responses and complications of FOLFOX-4 regimen as first line chemotherapy in elderly patients with advanced gastric cancer. Materials and Methods: From October 2014 to November 2015, a total of 21 patients with metastatic or local AGC (advanced gastric cancer) were analyzed. All patients were administered a FOLFOX-4 regimen consisting of a 2h infusion of oxaliplatin $85mg/m^2$ (day 1), continuous infusion of $1000mg/m^2$ 5-Fu in 24h., and leucovorin $200mg/m^2$ in 2h infusion as a first-line chemotherapy. Results: A total of 18 patients were assessable for efficacy and toxicity. One of 18 patients achieved a complete response, and 12 had partial responses, giving an overall response rate of 72.6%. Three (16%) patients demonstrated stable disease and 2 (12%) progression. The median progression free survival was 7.3 months, and the median overall survival was 11.9 months. One patient had grade 3 neuropathy. No other grade 3 or 4 NCI-CTC were seen. Conclusions: The FOLFOX-4 regimen used in our study was both active and acceptable for AGC in elderly patients as neoadjuvant and main therapy.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.9
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• pp.5263-5267
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• 2013

Background: The aim of this study was to evaluate the efficacy and tolerability of a gemcitabine, 5-fluorouracil and leucovorin (GEMFUFOL) chemotherapy regimen as first line treatment of metastatic biliary tract cancer. Materials and Methods: All patients received folinic acid $400mg/m^2$ on day 1, 5-fluorouracil bolus $400mg/m^2$ on day 1, IV infusion of 5-fluorouracil $2400mg/m^2$ over 46 hours, and gemcitabine $1250mg/m^2$ on day 1. Results: A total of 29 patients with metastatic biliary tract cancer received GEMFUFOL regimen as the firstline treatment. The mean follow-up was 22.1 months (95%CI, 12.5-31.8). One patient (3.4%) achieved complete response, 5 (17.2%) had partial response, and 4 (13.8%) had stable disease. The median progression-free survival was 3.3 months (95%CI, 2.9-3.7), and the median overall survival was 8.8 months (95%CI, 3.5-14). The 1-year and 2-year survival rates were 58.6% and 30%, respectively. Grade 3 and 4 toxicity included neutropenia in 4 patients (13.7%), thrombocytopenia in 2 (6.8%), anemia2 (6.8%), and alopecia in 1 (3.4%). Two patients (6.8%) developed febrile neutropenia. A dose reduction was achieved in 8 patients (27.6%) while 5 patients had extended-interval dosage (17.2%) for toxicity. Conclusions: The GEMFUFOL chemotherapy regimen was generally efficacious and tolerable as a first-line treatment of metastatic biliary tract cancer.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.24 no.6
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• pp.510-517
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• 2021

Purpose: Consensus is lacking regarding the optimal antibiotic treatment for pediatric complicated appendicitis. This study determined the optimal first-line antibiotic treatment for pediatric patients with complicated appendicitis based on peritoneal fluid cultures. Methods: This retrospective study examined the cases of pediatric patients who underwent appendectomy for complicated appendicitis at our institution between 2013 and 2019. Peritoneal fluid specimens obtained during appendectomy were cultured for the presence of bacteria. Results: Eighty-six pediatric patients were diagnosed with complicated appendicitis. Of them, bacteria were identified in 54 peritoneal fluid samples. The major identified bacteria were Escherichia coli (n=36 [66.7%]), Bacteroides fragilis (n=28 [51.9%]), α-Streptococcus (n=25 [46.3%]), Pseudomonas aeruginosa (n=10 [18.5%]), Enterococcus avium (n=9 [16.7%]), γ-Streptococcus (n=9 [16.7%]), and Klebsiella oxytoca (n=6 [11.1%]). An antibiotic susceptibility analysis showed E. coli was inhibited by sulbactam/ampicillin in 43.8% of cases versus cefmetazole in 100% of cases. Tazobactam/piperacillin and meropenem inhibited the growth of 96.9-100% of the major identified bacteria. E. coli (100% vs. 84.6%) and P. aeruginosa (100% vs. 80.0%) were more susceptible to amikacin than gentamicin. Conclusion: Tazobactam/piperacillin or meropenem is a reasonable first-line antibiotic treatment for pediatric complicated appendicitis. In the case of aminoglycoside use, amikacin is recommended.

• The Korean journal of helicobacter and upper gastrointestinal research
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• v.18 no.4
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• pp.242-246
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• 2018

Background/Aims: Helicobacter pylori eradication rates using first-line treatment have decreased due to clarithromycin resistance. The aim of this study was to investigate optimal eradication regimens for patients with clarithromycin resistance in Korea. Materials and Methods: A total of 72 patients with confirmed clarithromycin resistance were enrolled from August 2015 to July 2017. Patients were randomized to a 7-day bismuth quadruple therapy (BQT) regimen or a 7-day metronidazole triple therapy (MTT) regimen. Eradication was confirmed using the $^{13}C$-urea breath test. Results: There were no differences in baseline characteristics between the groups. Intention-to-treat eradication rates were 77.8% for the BQT group and 66.7% for the MTT group (P=0.293). Per protocol eradication rates were 87.5% for the BQT group and 77.4% for the MTT group (P=0.292). Adverse events were more frequent in the BQT group. Conclusions: Eradication rates using MTT were comparable to those using BQT, and adverse events were less frequent in the MTT group. Thus, MTT may be considered as a first-line regimen for patients with clarithromycin resistance. Since this was a pilot study, a study with a large group is required.