• The Journal of the Korean dental association
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• v.56 no.11
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• pp.605-614
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• 2018

PURPOSE. The purpose of this study is to determine the efficacy of the DENTIS submerged-type implant with an internal hex connection and to build corresponding abutment-selection criteria. MATERIAL AND METHODS. A total of 204 patients received submerged implant fixtures with an internal hex connection at the Dong-A University Hospital Dental clinic in Busan from January 2013 and May 2016. Three specific abutments, UCLA abutments, customized abutments, ready-made abutments, were randomly selected. Implant success was defined as the basis of the International Congress of Oral Implantologists(ICOI, 2007) criteria. The relationship between the implant success rate and the abutment factor was analyzed using the Kruskal-Wallis test(P<.05). RESULTS. A total of 508 implants were placed in 204 patients. After a mean observation period of 38.6 months, 493 out of 508 implants were in normal function, yielding an overall success rate of 97.05%. A total of 15 implants failed: 10 in the maxillary molar area, 4 in the mandibular molar area, and 1 in the mandibular incisal area. All of the implant failures occurred in a single-implant prosthesis, especially high in the maxillary molar area. The Kruskal-Wallis analysis showed that abutment selection has no significant correlation with implant failure(P>.05). CONCLUSION. DENTIS submerged implants with an internal hex connection showed predictable results with a success rate of 97.05%. It is no influence on the success rate in the selection of submerged implant abutment with an internal hex connection.

• The Journal of Economics, Marketing and Management
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• v.7 no.1
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• pp.1-14
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• 2019

Purpose - Currently, the economic globalization has become a common channel for China's enterprise to perform the international economic activities. Due to this background, this paper tries to analyze the influence of internationalization level on operation performance of enterprises. Research design, data, and Methodology - This paper aims at 296 companies going listed in Shanghai Stock Exchange and Shenzhen Stock Exchange. The data about the listed companies during the 12 years from 2005 to 2016 have been collected. Relevant theories, including the theory of comparative advantage, monopolistic advantage and product life cycle in developed countries as well as the small scale technology and state on localized technological capacities in developing countries, have been summarized to provide theoretical basis for the influence of international operation on operation performance of the enterprises. Moreover, the current status of international operation of China's enterprises, including the dynamic cause of the internationalization of China's enterprises, its competitive advantage and disadvantage as well as the interest and potential risk of the internationalization, have been also analyzed. Results - Via adopting the panel data to conduct an empirical analysis, It can be found that the relationship between international operation level and operation performance of China's enterprises can be expressed as the S-curve of declining, rising and declining again. Conclusions - This paper has taken the lead in using Ohlson corporate value model to fill the gap in the relevant researches in China. It can also provide guidance for the international operation of China's enterprises. Meanwhile, the two systems for international operation and performance evaluation index have been put forward. The performance of international operation can be classified as financial performance or corporate value so that the operation effect of those China's enterprises going abroad can be better evaluated.

• Biomolecules & Therapeutics
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• v.29 no.2
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• pp.184-194
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• 2021

Histone acetylation is a well-characterized epigenetic modification controlled by histone acetyltransferases (HATs) and histone deacetylases (HDACs). Imbalanced histone acetylation has been observed in many primary cancers. Therefore, efforts have been made to find drugs or small molecules such as HDAC inhibitors that can revert acetylation levels to normal in cancer cells. We observed dose-dependent reduction in the endogenous and exogenous protein expression levels of KAT8 (also known as human MOF), a member of the MYST family of HATs, and its corresponding histone acetylation at H4K5, H4K8, and H4K16 in chemotherapy drug gemcitabine (GEM)-exposed T24 bladder cancer (BLCA) cells. Interestingly, the reduction in MOF and histone H4 acetylation was inversely proportional to GEM-induced γH2AX, an indicator of chemotherapy drug effectiveness. Furthermore, pGL4-MOF-Luc reporter activities were significantly inhibited by GEM, thereby suggesting that GEM utilizes an MOF-mediated anti-BLCA mechanism of action. In the CCK-8, wound healing assays and Transwell® experiments, the additive effects on cell proliferation and migration were observed in the presence of exogenous MOF and GEM. In addition, the promoted cell sensitivity to GEM by exogenous MOF in BLCA cells was confirmed using an Annexin V-FITC/PI assay. Taken together, our results provide the theoretical basis for elucidating the anti-BLCA mechanism of GEM.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.47 no.3
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• pp.183-189
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• 2021

Objectives: To assess the prevalence and recovery of inferior alveolar nerve dysfunction (IAND) in mandibular fractures. Materials and Methods: This was a prospective cohort study. Clinical neurosensory testing was done preoperatively and the IAND was categorized as mild, moderate or severe. Postoperatively, neurosensory testing was repeated at 1 day, 1 week, 1 month, 3 months and every 3 months thereafter. Results: A total of 257 patients with 420 fractures were included in the study with a mean age of 31.7 years. Body fractures (95.9%) had the highest incidence of IAND, followed by the angle fractures (90.1%) and symphysis fractures (27.6%). The condyle and coronoid fractures did not have any IAND and hence were excluded from further study. After eliminating those cases, 232 patients remained in the study with 293 fractures. The overall prevalence of IAND in fractures occurring distal to the mandibular foramen was 56.3%. The changes until 1 week were minimal. From 1 month to 6 months, there was a significant reduction in the severity of IAND. A significant number of cases (60.0%) were lost to follow-up between 6 and 9 months. At 6 months, 23.9% of cases still had some form of IAND and 95.0% of the symphysis, 59.0% of the angle and 34.8% of the body fractures with IAND had become normal. Conclusion: This study documents the reduction in the degree of severity of IAND in the first six months and provides the basis for future studies with longer periods of follow-up.

• Korean Journal of Chemical Engineering
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• v.35 no.11
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• pp.2283-2289
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• 2018

$TiO_2$ microspheres were successfully synthesised by simple solution phase method by using various amount of titanium butoxide as precursor. The prepared $TiO_2$ were characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance absorption spectra (UV-DRS), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). XRD analysis revealed that the as-synthesized $TiO_2$ microsphere poses an anatase phase. The photocatalytic degradation experiments were carried out with three different dyes, such as methylene blue, brilliant black, reactive red-120 for four hours under UV light irradiation. The results show that $TiO_2$ morphology had great influence on photocatalytic degradation of organic dyes. The experimental results of dye mineralization indicated the concentration was reduced by a high portion of up to 99% within 4 hours. On the basis of various characterization of the photocatalysts, the reactions involved to explain the photocatalytic activity enhancement due to the concentration of titanium butoxide and morphology include a better separation of photogenerated charge carriers and improved oxygen reduction inducing a higher extent of degradation of aromatics.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.12
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• pp.1670-1675
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• 2020

In this study, to provide the basis for establishing effective network based countermeasures against DRDoS(Distributed Reflection Denial of Service) attacks, we propose a new 'DRDoS attack multi-level detection method' that identifies the network based characteristics of DRDoS and applies probability and statistical techniques. The proposed method removes the limit to which normal traffic can be indiscriminately blocked by unlimited competition in network bandwidth by amplification of reflectors, which is characteristic of DRDoS. This means that by comparing 'Server to Server' and 'Outbound Session Incremental' for it, accurate DRDoS identification and detection is possible and only statistical and probabilistic thresholds are applied to traffic. Thus, network-based information security systems can take advantage of this to completely eliminate DRDoS attack frames. Therefore, it is expected that this study will contribute greatly to identifying and responding to DRDoS attacks.

• Journal of The Korean Society of Integrative Medicine
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• v.8 no.4
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• pp.107-115
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• 2020

Purpose: This study aims to systematically review the dual-task evaluation applied to the screening of mild cognitive impairment. It also aims to present various evaluation items and results analysis methods for dual tasks applied to patients with mild cognitive impairment. Methods: We conducted a systematic search of published studies in PubMed databases and KISS from January 2000 to August 2020 using the main keywords such as "Dual task," "Mild Cognitive impairment," "Elderly," and "Screening." We selected a total of 10 studies for the analysis from 1314 searched articles. Results: We analyzed the qualitative level of 10 studies that were nonrandomized two-group studies with evidence level II (100.0%). These results suggest that the evidence level of the studies was high. We analyzed 10 studies and identified 12 motor tasks and 19 cognitive tasks. Walking was the most commonly used evaluation motor task and counting backward by ones and naming animals were the most commonly used evaluation cognitive tasks. Moreover, the velocity speed was the most used result analysis method. The results indicate that there were significant differences in dual-task performance between patients with normal and mild cognitive impairment. Conclusion: The results of this study can be used as a basis for the selection of dual-task evaluation items and methods of analyzing the results for screening mild cognitive impairment. Furthermore, they are expected to be used for research on the development of dual-task evaluation tools. It is necessary to compare and analyze the usage trends of dual-task evaluation by cultural differences in future studies.

• Geomechanics and Engineering
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• v.24 no.4
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• pp.307-321
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• 2021

In an earlier publication (Serrano et al. 2014), the theoretical basis for evaluating the shear strength in rock joints was presented and used to derive an equation that governs the relationship between tangential and normal stresses on the joint during slippage between the joint faces. In this paper, the theoretical equation is applied to two non-linear failure criteria by using non-associated flow laws, including the modified Hoek and Brown and modified Mohr-Coulomb equations. The theoretical model considers the geometric dilatancy, the instantaneous friction angle, and a parameter that considers joint surface roughness as dependent variables. This model uses a similar equation structure to the empirical law that was proposed by Barton in 1973. However, a good correlation with the empirical values and, therefore, Barton's equation is necessary to incorporate a non-associated flow law that governs breakage processes in rock masses and becomes more significant in highly fractured media, which can be induced in a rock joint. A linear law of dilatancy is used to assess the importance of the non-associated flow to obtain very close values for different roughness states, so the best results are obtained for null material dilatancy, which considers significant changes that correspond to soft rock masses or altered zones of weakness.

• Nuclear Engineering and Technology
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• v.54 no.5
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• pp.1674-1685
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• 2022

The ball valve is an important device in the pipeline transportation system of nuclear power plants. Its operational stability and safety directly affect the normal working of nuclear power plants. In this study, the transient numerical simulation of the opening and closing process of a ball valve was conducted on the basis of the flow interruption capability experiment of the ball valve by using the moving mesh method and inlet and outlet variable boundary conditions. The flow rate and pressure difference with time of the opening and closing process of the ball valve were studied. The internal flow characteristics of the ball valve under different relative openings were analyzed in conjunction with the typical back-step flow structure. Results show that the transient numerical results agree well with the experimental results. The internal flow characteristics of the ball valve are similar at the same opening during opening and closing process. At small opening, the spool and outlet channels easily form a back-step flow structure. The disappearance and generation of backflow vortices during opening and closing occur at 85% opening and 75% opening, respectively. With the decrease in opening degree, the difference in vortex core area in the flow channel of the ball valve spool in the opening and closing process gradually appears. The research results provide some reference value for the design and optimization of ball valves.

• Journal of Internet Computing and Services
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• v.23 no.5
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• pp.135-143
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• 2022

As the world has implemented social distancing and telecommuting due to the spread of COVID-19, real-time streaming sessions based on routing protocols have increased dependence on the Internet due to the activation of video and voice-related content services and cloud computing. BGP is the most widely used routing protocol, and although many studies continue to improve security, there is a lack of visual analysis to determine the real-time nature of analysis and the mis-detection of algorithms. In this paper, we analyze BGP data, which are powdered as normal and abnormal, on a real-world basis, using an anomaly detection algorithm that combines statistical and post-processing statistical techniques with Rule-based techniques. In addition, we present an interactive spatio-temporal analysis plan as an intuitive visualization plan and analysis result of the algorithm with a map and Sankey Chart-based visualization technique.