• Asian Pacific Journal of Cancer Prevention
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• v.14 no.1
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• pp.381-386
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• 2013

Aims: The aim of this study was to investigate the effects of adjuvant chemotherapy cycles on the prognosis of patients with post-operative stomach cancer through retrospective analysis. Methods: A total of 128 patients with gastric cancer who underwent gastrectomy, followed by adjuvant chemotherapy consisting of epirubicin, cisplatin or oxaliplatin, leucovorin, and 5-fluorouracil, according to a defined schedule, were divided into three groups according to the number of chemotherapy cycles: Group I (<6 cycles); Group II (6 cycles); and Group III (>6 cycles). Results: The 5-year overall survival (OS) was 20.8% in Group I, 45.0% in Group II, and 42.9% in Group III, with a median follow-up of 43 months. The 5-year relapse-free survival (RFS) was 15.1% in Group I, 40% in Group II, and 40% in Group III. The OS and RFS in Groups II and III were significantly better than in Group I (OS, p = 0.002 and p=0.003; RFS, P<0.001 and P=0.002). There was no difference in OS (p = 0.970) or in RFS (p = 0.722) between Groups II and III. Multivariate Cox hazard analysis determined that the number of adjuvant chemotherapy cycles was an independent factor that influenced OS and RFS. Conclusion: Six cycles of adjuvant chemotherapy gave encouraging outcomes in patients with resectable gastric cancer. Further prospective randomized controlled investigations are warranted in a multi-center setting.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.12 s.103
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• pp.1239-1245
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• 2005

In this paper, a new predistortion linearizer using second harmonic components feedforwarding is proposed. The harmonic generator of the proposed predistorter that consists of a small signal amplifier extracts second harmonic signals. A vector modulator that modulate fundamental signal with second harmonic signals, generates the inverse third order intermodulation distortion signals and controls amplitude/phase of them with modulation factors. As a result, this linearizer is suppressed IMD3 signals of power amplifier effectively. The test results show that the third order IMD of power amplifier is suppressed more than 20 dB for CW two-tone signals. Also, it's improved the adjacent channel power ratio(ACPR) more than 5 dB for CDMA(IS-95) 4FA signals.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.4
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• pp.1644-1651
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• 2013

The purpose of this study was to investigate the influence of distance education experience using users' avatars in virtual reality space on their teaching efficacy belief. There were 9 participants who were enrolled in a course in doctoral program of education department in J University for the study. The first class of six sessions was face to face class on how to use Second Life and the 14 classes of 3 sessions were done in a classroom of Second Life. According to the analysis of reflection notes, interviews, researcher's observations of 5 participants, their experiences of presentation and taking classes in distance education using their own avatars in Second Life had positive influence on participants' teaching efficacy belief in their future working for distance education using avatars of Second Life. The implication of this study is to show some conditions for successful distance education as well as to see the potential of distance education in 3D virtual reality space using avatars. This study will contribute to promote the future study in distance education field.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.3
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• pp.239-245
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• 1989

This experiment was conducted to study the physiological and ecological responses of agronomic characters related to source and sink relation in rice. Standard deviation and coefficient of variability of agronomic characters by individual tiller were greatly influenced by the lower internodes in the length of internode, flag leaf in the leaf blade, lower leaf blade in the leaf width, and the number and spikelets of secondary rachis branch in panicle. In relation to the parts of source and sink of rice plant and the number of spikelet in panicle, the number of spikelet was significantly correlated with the length and leaf area of second leaf blade, the length of second internode, and culm diameter of third internode. The correlation of the length of panicle with the length of internode and leaf blade was greatly influenced by the length of second leaf blade and second internode. The number of spikelet was increased with increasing the second rachis branch rather than first rachis branch. The content of total inorganic nutrients was greatest at leaf blade followed by leaf sheath and internode, and panicle.

• Restorative Dentistry and Endodontics
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• v.41 no.1
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• pp.55-62
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• 2016

Objectives: The purpose of this study was to investigate the incidence of root fusion and C-shaped root canals in maxillary molars, and to classify the types of C-shaped canal by analyzing cone-beam computed tomography (CBCT) in a Korean population. Materials and Methods: Digitized CBCT images from 911 subjects were obtained in Chosun University Dental Hospital between February 2010 and July 2012 for orthodontic treatment. Among them, a total of selected 3,553 data of maxillary molars were analyzed retrospectively. Tomography sections in the axial, coronal, and sagittal planes were displayed by PiViewstar and Rapidia MPR software (Infinitt Co.). The incidence and types of root fusion and C-shaped root canals were evaluated and the incidence between the first and the second molar was compared using Chi-square test. Results: Root fusion was present in 3.2% of the first molars and 19.5% of the second molars, and fusion of mesiobuccal and palatal root was dominant. C-shaped root canals were present in 0.8% of the first molars and 2.7% of the second molars. The frequency of root fusion and C-shaped canal was significantly higher in the second molar than the first molar (p < 0.001). Conclusions: In a Korean population, maxillary molars showed total 11.3% of root fusion and 1.8% of C-shaped root canals. Furthermore, root fusion and C-shaped root canals were seen more frequently in the maxillary second molars.

• The Journal of the Korean dental association
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• v.56 no.2
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• pp.84-93
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• 2018

Purpose: This study evaluated the apical root canal system of maxillary second molars, in which conventional endodontic treatment had failed. Materials and Methods: One hundred eighteen extracted endodontically failed maxillary second molars were examined to investigate the root canal morphology using clinical photographs. High-resolution cross-sectional images at the 3mm level from the root apices were taken to evaluate the anatomic variations and canal cleanliness. The incidence of anatomic variations and canals containing debris were evaluated statistically. Results: One (0.85%) maxillary second molar had four separate roots, while 52 (44.07%) had three separate roots. The remaining 65 (55.08%) showed 6 different types of fusion in their roots. As the number of fused roots increased from none to three, the incidence of isthmuses in the cross-sectional images increased significantly from 43.40% to 76.92% in 2-root fusion and 88.46% in 3-root fusion. In addition, the occurrence of less-cleansed canals increased from 22.64% to 38.46% and 53.85%, respectively (p<0.05). Sixty four teeth (54.24%) had 3 canals while 38(32.2%) had additional canals; most of them were located in the MB roots (81.58%). Seventy six (64.41%) had isthmuses in the apical region and 58 out of 76 were located in MB roots. Condlusions: Logistic analysis indicated that the less division of roots was associated significantly with the occurrence of insufficient cleaning during endodontic treatment (OR=1.765, p<0.05), while the presence of an additional canal showed no association.

• Perinatology
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• v.29 no.4
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• pp.159-164
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• 2018

Objective: To compare neonatal respiratory morbidity of twins according to birth order related to gestational age and mode of delivery. Methods: We performed the retrospective research of the medical records of 3,224 neonates (1,612 twin pairs) born in a single center from January 2011 to December 2015. Subjects were classified into four gestational age groups: very (<32 weeks), moderate (32-33 weeks), late (34-36 weeks) preterm, and term (${\geq}37weeks$) groups. We investigated clinical characteristics and respiratory morbidity according to birth order related to gestational age group and mode of delivery. Results: We found increased risk of respiratory morbidity in second-born twin than first-born twin (P=0.039). Second-born twin was associated with increased risk of respiratory distress syndrome (RDS) in late preterm group (odds ratio [OR] 2.8, 95% confidence interval [CI] 1.30-5.95), and transient tachypnea of newborn in term group (OR 1.4, 95% CI 1.03-1.81). In vaginal delivery mode, there was no difference of respiratory morbidity between first and second-born twin in each group, but in cases of Cesarean delivery, second-born twin was related with a greater risk of RDS in late preterm group (OR 2.3, 95% CI 1.07-5.09). Birth order and Cesarean section independently increased the risk of RDS (adjusted OR [aOR] 1.69, 95% CI 1.12-2.54; aOR 2.14, 95% CI 1.25-3.66, respectively). Conclusion: Second-born twin and Cesarean delivery are associated with increased risk of RDS, especially in late preterm twins.

• The Korean Journal of Emergency Medical Services
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• v.24 no.3
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• pp.7-27
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• 2020

Purpose: The purpose of this study is to identify the compliance with the first standardization of the paramedic curriculum and suggest a second standardization to cultivate competent paramedics. Methods: This study was conducted by collecting 38 curricula, and responses to questionnaires, including those on the current status of prehospital field practice, from departments of emergency medical technology of 36 institutions. Data were collected between September 1 and November 30, 2019 via e-mail. Data were analyzed using SPSS v24.0 and NVivo 12.0. Results: Compliance with the first standardization of the paramedic curriculum was over 70% in only 11 on the 26 major subjects. The second standardization of the paramedic curriculum consists of 27 subjects requiring 76~79 credits for the 3-year course and 78~82 credits for the 4-year course. Conclusion: We suggested a minimum number of essential subjects to cultivate competent paramedics following the second standardization of the paramedic curriculum, and we hope colleges comply with this curriculum. Twenty to twenty-five percent of major subjects can be determined by the discretion of the college to maximize competency of paramedic students.

• Journal of Digital Convergence
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• v.20 no.2
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• pp.317-323
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• 2022

This study aimed to qualitative analyze the cusp variation pattern of the mandibular second premolars using a three-dimensional virtual models, and to analyze the left-right bilateral symmetry with a quantitative analysis of the tooth surface area according to the cusp variation. 127 virtual mandibular second premolars were prepared and individual absolute/relative cusp area, total crown area and groove form were analyzed using RapidForm2004(INUS technology INC, Seoul, Korea). Independent t-test, Kruskal-Wallis test and chi-square were performed. As a result, the groove form showed high bilateral symmetry between the left and right sides. Based on the left side of groove form, the bilateral symmetry was 100.0% for the U pattern, and 73.7% for the H patterned, and 78.9% for the Y pattern(p<.001). The finding could be as a meaningful reference for manufacturing CAD/CAM dental prostheses, and it is expected that further studies will be conducted on more samples including the mandibular second premolar immediately after eruption.

• Bulletin of the Korean Mathematical Society
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• v.34 no.3
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• pp.411-419
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• 1997

Using the theory of strongly continuous cosine families, we prove controllable of nonlinear second order control system and give an application.