• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.3
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• pp.285-292
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• 2008

Purpose: The present study was performed to evaluate the effect of surface treatment of the cervical area of implant on bone regeneration in fresh extraction socket following implant installation. Materials and methods: The four minipigs, 18 months old and 30 kg weighted, were used. Four premolars of the left side of both the mandible and maxilla were extracted. ${\phi}$3.3 mm and 11.5 mm long US II plus implants (Osstem Implant co., Korea) with resorbable blasting media (RBM) treated surface and US II implants (Osstem Implant co., Korea) with machined surface at the top and RBM surface at lower portion were installed in the socket. Stability of the implant was measured with $Osstell^{TM}$ (Model 6 Resonance Frequency Analyser: Integration Diagnostics Ltd., Sweden). After 2 months of healing, the procedures and measurement of implant stability were repeated in the right side by same method of left side. At four months after first experiment, the animals were sacrificed after measurement of stability of all implants, and biopsies were obtained. Results: Well healed soft tissue and no mobility of the implants were observed in both groups. Histologically satisfactory osseointegration of implants was observed with RBM surface, and no foreign body reaction as well as inflammatory infiltration around implant were found. Furthermore, substantial bone formation and high degree of osseointegration were exhibited at the marginal defects around the cervical area of US II plus implants. However, healing of US II implants was characterized by the incomplete bone substitution and the presence of the connective tissue zone between the implant and newly formed bone. The distance between the implant platform (P) and the most coronal level of bone-to-implant contact (B) after 2 months of healing was $2.66{\pm}0.11$ mm at US II implants group and $1.80{\pm}0.13$mm at US II plus implant group. The P-B distance after 4 months of healing was $2.29{\pm}0.13$mm at US II implants group and $1.25{\pm}0.10$mm at US II plus implants group. The difference between both groups regarding the length of P-B distance was statistically significant(p<0.05). Concerning the resonance frequency analysis (RFA) value, the stability of US II plus implants group showed relatively higher RFA value than US II implants group. Conclusion: The current results suggest that implants with rough surface at the cervical area have an advantage in process of bone regeneration on defect around implant placed in a fresh extraction socket.

• Korean Journal of Radiology
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• v.24 no.12
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• pp.1284-1292
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• 2023

Objective: We investigated the impacts of computed tomography (CT) added to ultrasound (US) for preoperative evaluation of patients with papillary thyroid carcinoma (PTC) on staging, surgical extent, and postsurgical survival. Materials and Methods: Consecutive patients who underwent surgery for PTC between January 2015 and December 2015 were retrospectively identified. Of them, 584 had undergone preoperative additional thyroid CT imaging (CT + US group), and 859 had not (US group). Inverse probability of treatment weighting (IPTW) and propensity score matching (PSM) were used to adjust for 14 variables and balance the two groups. Changes in nodal staging and surgical extent caused by CT were recorded. The recurrence-free survival and distant metastasis-free survival after surgery were compared between the two groups. Results: In the CT + US group, discordant nodal staging results between CT and US were observed in 94 of 584 patients (16.1%). Of them, CT accurately diagnosed nodal staging in 54 patients (57.4%), while the US provided incorrect nodal staging. Ten patients (1.7%) had a change in the extent of surgery based on CT findings. Postsurgical recurrence developed in 3.6% (31 of 859) of the CT + US group and 2.9% (17 of 584) of the US group during the median follow-up of 59 months. After adjustment using IPTW (580 vs. 861 patients), the CT + US group showed significantly higher recurrence-free survival rates than the US group (hazard ratio [HR], 0.52 [95% confidence interval {CI}, 0.29-0.96]; P = 0.037). PSM analysis (535 patients in each group) showed similar HR without statistical significance (HR, 0.60 [95% CI, 0.31-1.17]; P = 0.134). For distant metastasis-free survival, HRs after IPTW and PSM were 0.75 (95% CI, 0.17-3.36; P = 0.71) and 0.87 (95% CI, 0.20-3.80; P = 0.851), respectively. Conclusion: The addition of CT imaging for preoperative evaluation changed nodal staging and surgical extent and might improve recurrence-free survival in patients with PTC.

• East Asian Economic Review
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• v.21 no.3
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• pp.231-257
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• 2017

The particular market situation provision of the WTO Antidumping Agreement is increasingly invoked against what may be described as "input-dumping," but this potentially violates the current Antidumping Agreement rules. This paper examines the practice and recent changes regarding the PMS provision in the US by critically examining relevant antidumping investigations in the US in light of GATT/WTO jurisprudence. Such US practice has not yet been extensively subjected to scholarly examination. The paper finds that the recent legal change in the US widens the scope and applicability of the PMS provision to cover input subsidies, allowing the use of not only surrogate prices but also surrogate costs. Further, the required standard of evidence to find PMS seems to have been diminished in the recent application. A widespread use of the PMS provision in such a deviant way calls for a fundamental review of the current trade remedy rules of the WTO.

• East Asian Economic Review
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• v.20 no.3
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• pp.311-338
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• 2016

In the race for establishing trading architecture consistent with new landscape of the global economy, the US is ahead of the game by concluding the Trans Pacific Partnership Agreement with 11 countries. To make it reality, the ratification is essential. In the battle for ratification in the US, declining globalism confronts rising protectionism. This paper models the ratification process as contest between globalism and protectionism, and analyzes the optimal timing for ratification. Based on this framework, various ratification scenarios are analyzed. The paper argues less likelihood for the lame-duck session passage and more likelihood for prolonged and protracted delay, due to changing political dynamics and declining intellectual support for globalism. Hence, the future of Trans Pacific Partnership Agreement may prove different, compared to the North American Free Trade Agreement and the Korea-US Free Trade Agreement, both of which were renegotiated and ratified eventually. Then, the US would lose the first move advantage. The paper also discusses strategic implications of delayed ratification on the evolution of trading architecture in East Asia.

• Korean Journal of Radiology
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• v.21 no.4
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• pp.442-449
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• 2020

Objective: To compare the diagnostic performance of contrast-enhanced spectral mammography (CESM) versus ultrasonography (US) in symptomatic patients with dense breasts, while using histology as the gold standard. Materials and Methods: After obtaining approval from the local ethics board, this prospective study collected data from patients with symptomatic breasts who underwent CESM and US examinations from May 1, 2017 to September 30, 2017. We then selected those with dense breasts and pathological results as our sample population. Both CESM and US results were classified by a radiologist through the Breast Imaging Reporting and Data System, and the results were compared with their corresponding histological results. The chi-square test was conducted to compare the diagnostic performance of CESM and US, and the receiver operating characteristic curves for the two imaging modalities were obtained. Results: A total of 131 lesions from 115 patients with dense breasts were included in this study. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were 93.8%, 88.1%, 88.2%, 93.7%, and 90.8% for CESM, and 90.6%, 82.1%, 82.9%, 90.2%, and 86.3% for US, respectively. The p values for sensitivity, specificity, PPV, NPV, and accuracy were 0.687, 0.388, 0.370, 0.702, and 0.238, respectively. The area under the curve of CESM (0.917) was comparable with that of US (0.884); however, the differences between CESM and US were not statistically significant (p = 0.225). Eight false-positive cases and 4 false-negative cases for breast cancer were found in CESM, while 12 false-positive cases and 6 false-negative cases were found in US. Conclusion: The diagnostic performances of CESM and US are comparable in symptomatic women with dense breasts; however, the routine use of additional US imaging is questionable for lesions that can be detected by CESM.

• Journal of radiological science and technology
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• v.37 no.4
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• pp.295-305
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• 2014

This study is to provide accurate information as medical imaging equipment to check for the presence of body disease US equipment. We investigated the status of medical US equipment performance in Daegu and criteria US phantom (ATS-539) for US equipment performance measurements. The results in this study, 1. US phantom measurement results: The test passed rate were 88.6% and the failed rate were 11.4%. 2. The difference between the group of mean and the pass/failed groups were statistically significant. Focal zone and 4 mm functional resolution in the two items that are not present the passing standard. 3. The difference was statistically significant number of years and used equipment and pass the failed equipment (4.13 vs 7.25 years). We investigated the performance status of US equipment used in the clinical area in Daegu. The basis for the two items are not present this proposed passing standard. Equipment performance was associated with the number of years of using US equipment. It is necessary to maintain the best performance of the equipment phantom measurements for performance testing of US equipment.

• The Journal of Information Systems
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• v.10 no.2
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• pp.89-101
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• 2001

The purpose of this research is empirically investigating organizational/managerial factors affecting BPR implementation between Korean and US companies. And we compared the critical success factors and business innovation performance of Korean companies to those of US companies based on the prior research. Seven variables that represent success of BPR implementation are identified. They are : (1) reduction of process time (2) reduction of process cost (3) upgraded skill or knowledge (4) improved quality of process output (5) improved quality of work life (6) responsiveness to customer need (7) overall perception of BPR success. The result showed that the performance of US companies is better than that of Korean companies. Especially level of overall perception of BPR success of US companies is more high than that of Korean companies. The reason is that business innovation of Korean companies is focused on functional unit and incremental improvement.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.20
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• pp.8613-8616
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• 2014

Background: The diagnostic approach to thyroid nodules involves ultrasound-guided fine needle aspiration biopsy (US-FNAB). We especially aimed to evaluate the contribution and the place of US-FNAB in preoperative evaluation of the malignant cases and draw attention to discordant cases diagnosed with papillary thyroid microcarcinoma (PTMC). Materials and Methods: A total of 276 cases were retrospectively reviewed who were subsequently diagnosed with a malignancy and who underwent US-FNAB. Results: Some 45 were found to have previously undergone the US-FNAB procedure. Of the patients in whom the surgical specimen was diagnosed with a malignancy, 21 (46.7%) were diagnosed as malignant or suspicious for malignancy, and 24 (53.3%) were concluded as benign or insufficient for diagnosis. Patients with the diagnosis of PTMC outnumbering the others was a striking finding (11 cases, 24%). Conclusions: We suggest performing repeat aspiration biopsy considering sampling errors in cases where inconsistency exists between clinical findings and cytological results in thyroid nodules smaller than 10 mm in diameter and with suspicious findings on ultrasonography.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.4 no.1 s.6
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• pp.89-95
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• 2005

In this paper, a quad-band antenna for GSM/GPS/DCS/US-PCS handsets is proposed. The proposed antenna is low-profile for mounting in limited inner space of a handset. It consists of three open points with quarter wave length for multi-band operation. The ground plane below the patch is removed for wide-bandwidth without the variation of antenna size and the slot is added at the center of the patch for convenient matching in high frequency band. It provides a enough bandwidth within VSWR 3:1 at all bands. In addition, the measured peak gains are between -2.19 and 2.09 in anechoic chamber (10m$\times$6m$\times$4m).

• Research in Community and Public Health Nursing
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• v.28 no.2
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• pp.173-181
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• 2017

Purpose: Early sexual intercourse is associated with poor health outcomes in adolescents. It is known that sexual intercourse coincides with other health risk behaviors such as smoking, drinking, and using drugs. The purpose of this study is to identify the relationships between sexual intercourse and health risk behaviors among Korean and US adolescents using nationally representative data. Methods: Data were collected from the 2011 Korea Youth Risk Behavior Web-based Survey (29,676 students) and 2011 Youth Risk Behavior Surveillance System (10,135 high school students). Logistic regression analysis was performed. Results: In Korea, students who had sexual intercourse accounted for 7.0% in total. Among these, 9.7% were male and 4.2% were female students. In the US, a total of 51.3% students had sexual intercourse, and the proportion of the US male (49.3%) and female (53.4%) students who had sexual intercourse was similar. Korean and US students who experienced sexual intercourse were more likely to smoke, drink alcohol, and use drugs. Conclusion: Since the results of this study show the relationships between sexual intercourse and health risk behaviors, it is necessary to develop comprehensive sex education programs with effective strategies to reduce health risk behaviors in adolescents.