• Korean Journal of Clinical Laboratory Science
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• v.52 no.2
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• pp.128-135
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• 2020

Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterium that causes infections in different parts of the body and causes skin and soft tissue infections (SSTI). The present study examined the antimicrobial resistance patterns and molecular epidemiological characteristics of MRSA isolated from nasal swabs in clinical patients. SCCmec type of MRSA isolates from clinical patients were analyzed: 24 cases were SCCmec type-II; two cases were type-II/IVa; one case was type-II/V; one case was type-IVa; 11 cases were not-typeable. The mec complex type of MRSA isolates from clinical patients were analyzed: 29 cases were mec complex type A, and 10 cases were not-typeable, but type B was not found in the present study. In conclusion, SCCmec type-II and mec complex type A were the most dominant MRSA subtypes among the MRSA isolates from a nasal swab of patients, and the results were similar to other studies on hospital-acquired MRSA (HA-MRSA). These results can not only provide basic data for hospital infection management but also be a good guideline for MRSA infections in the Republic of Korea.

• Journal of Life Science
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• v.26 no.11
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• pp.1259-1268
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• 2016

In this study, we investigated antimicrobial peptide from the acidified muscle extract of Mytilus coruscus, which mostly inhabits China, Japan, and Korea, to develop a natural product-derived antibiotics substitution in terms of its abuse and restriction. Antimicrobial peptide was purified by $C_{18}$ reversed-phase high-performance liquid chromatography and was detected as having a molecular mass of 6,701 Da by MALDI-TOF/MS. The N-terminal amino acid sequence of the purified peak was obtained from edman degradation, and 20 identified residues shown 100% identity with the N-terminus region of sperm-specific protein and protamine-like PL-II/PL-IV precursor of Mytilus californianus. We also identified 60 open-reading frame (ORF) encoding amino acids with 183 bp of purified peptide based on the obtained amino acid residues. The amino acid sequence of ORF showed 100% and the nucleotide sequence revealed 97.2% identity with the protamine-like PL-II/PL-IV precursor of Mytilus californianus. Synthesized antimicrobial peptide showed antimicrobial activity against gram-positive bacteria, including Bacillus cereus (minimal effective concentration [MEC], $20.8{\mu}g/ml$), Bacillus subtilis (MEC, $0.2{\mu}g/ml$), Streptococcus mutans (MEC, $0.2{\mu}g/ml$), gram-negative bacteria including Pseudomonas aeruginosa (MEC, $5.7{\mu}g/ml$), Escherichia coli (MEC, $2.6{\mu}g/ml$) and fungi, Candida albicans (MEC, $56.3{\mu}g/ml$). In addition, synthesized peptide showed stable activities under heat and salt conditions against gram-positive and gram-negative bacteria, but was inhibited by salt against only C. albicans. With these results, isolated peptide from M. coruscus could be an alternative agent to antibiotics for defending against pathogenic microorganisms, and helpful information to understand the innate immune system of marine invertebrates.

• Journal of Microbiology and Biotechnology
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• v.20 no.4
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• pp.798-802
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• 2010

Recently, a total of 74 Staphylococcus pseudintermedius isolates were collected from clinical cases of canine pyoderma and otitis externa in Korea. In this study, we examined in vitro fluoroquinolone resistance among those isolates using a standard disc diffusion technique. The results demonstrated that, except for one isolate, approximately 18.9% to 27.0% of the isolates possessed bacterial resistance to both veterinary- and human-licensed fluoroquinolones including moxifloxacin (18.9% resistance), levofloxacin (20.3% resistance), ofloxacin (24.3% resistance), ciprofloxacin (25.7% resistance), and enrofloxacin (27.0% resistance). Most surprisingly, 14 out of 74 (18.9%) isolates were resistant to all the five fluoroquinolones evaluated. Moreover, a PCR detection of the methicillin resistance gene (mecA) among the 74 isolates revealed that 13 out of 25 (52.0%) mecApositive isolates, but only 7 out of 49 (14.3%) mecA-negative isolates, were resistant to one or more fluoroquinones. Taken together, our results imply that bacterial resistance to both veterinary- and human-use fluoroquinolones becomes prevalent among the S. pseudintermedius isolates from canine pyoderma and otitis externa in Korea, as well as that the high prevalence of the mecA-positive S. pseudintermedius isolates carrying multiple fluoroquinolones resistance could be a potential public health problem.

• Korean Journal of Head & Neck Oncology
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• v.33 no.1
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• pp.39-41
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• 2017

Salivary gland tumors comprise almost 5% of head and neck malignancies, and minor salivary gland tumor which account for 10-15% of all salivary gland neoplasm are infrequently malignant. The mucoepidermoid carcinoma (MEC) is second most common tumor in minor salivary gland. It usually presents as a painless, rubbery-hard or soft mass, which may be fixed or mobile into the underlying structure. The predilection sites of intraoral MEC are palate, cheek, mandible, lip, and tongue, etc. There are very few published reports of MEC occurred in retromolar trigone. Only one case has been reported so far. Recently, we experienced a-70-year old man with a mass in retromolar trigone, which was finally diagnosed as MEC. We report the unique case with literature review.

• Korean Journal of Head & Neck Oncology
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• v.34 no.2
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• pp.89-92
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• 2018

Malignant salivary gland tumors only represent 0.08% of all childhood tumors. Especially, nasopharyngeal mucoepidermoid carcinoma(MEC) in pediatric age is an extremely rare malignancy. We hereby report a case of nasopharyngeal MEC in 5 year-old female patient. The patient underwent the complete removal of the tumor by endonasal endoscopic approach. Adjuvant postoperative radiotherapy was not considered. After 3.5 years of follow-up, there are no sign of recurrence and metastasis. Minor salivary gland tumor must be considered as a differential diagnosis of angiofibroma in nasopharynx in pediatric age. To our knowledge, the case we describe is the third case of nasopharyngeal MEC in pediatric age reported in literature.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.5
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• pp.1238-1259
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• 2024

Previous studies on joint optimization of computation offloading and service caching policies in Mobile Edge Computing (MEC) have often neglected the impact of dependency-aware subtasks, edge server resource constraints, and multiple users on policy formulation. To remedy this deficiency, this paper proposes a many-objective joint optimization dependency-aware task offloading and service caching model (MaJDTOSC). MaJDTOSC considers the impact of dependencies between subtasks on the joint optimization problem of task offloading and service caching in multi-user, resource-constrained MEC scenarios, and takes the task completion time, energy consumption, subtask hit rate, load variability, and storage resource utilization as optimization objectives. Meanwhile, in order to better solve MaJDTOSC, a many-objective evolutionary algorithm TSMSNSGAIII based on a three-stage mating selection strategy is proposed. Simulation results show that TSMSNSGAIII exhibits an excellent and stable performance in solving MaJDTOSC with different number of users setting and can converge faster. Therefore, it is believed that TSMSNSGAIII can provide appropriate sub-task offloading and service caching strategies in multi-user and resource-constrained MEC scenarios, which can greatly improve the system offloading efficiency and enhance the user experience.

• Korean Journal of Food Science and Technology
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• v.37 no.3
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• pp.456-464
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• 2005

Antimicrobial drug-resistance is natural response to antimicrobial stress based on selection, which weakens chemotherapy effect. Introduction of large numbers of chemotherapeutic agents to clinical practice has generated strains of microorganisms that survive and multiply in vivo with high-drug concentrations. Methicillin-resistant Staphylococcus aureus (MRSA), bacteria found in normal daily life, can be easily ingested through milk vegetables, and meats, etc. MRSA emerged in many port of the world, increasing complex clinical problems. Therefore, new agents are needed to treat MRSA. Glycyrrhiza uralensis was extracted using 80% MeOH to investigate its antimicrobial activity against MRSA stains KCCM 11812, 40510, and 40512 through bacterial measurement, disc diffusion, and O.D. methods, MIC values, MRSA gene expression investigation, and scanning electron microscope observation. Results revealed MecA, Mecl, MecRI, and FemA were the most highly manifested MRSA genes. Methanolic extract of G. uralensis significantly inhibited MRSA and thus could be used in development of antibacteria.

• KIPS Transactions on Computer and Communication Systems
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• v.10 no.12
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• pp.311-318
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• 2021

With the rapid development of the Internet of Things(IoT) technology recently, multi-access edge computing(MEC) is emerged as a next-generation technology for real-time and high-performance services. High mobility of users between MECs with limited service areas is considered one of the issues in the MEC environment. In this paper, we consider a vehicle edge computing(VEC) environment which has a high mobility, and propose a task migration algorithm to decide whether or not to migrate and where to migrate using DQN, as a reinforcement learning method. The objective of the proposed algorithm is to improve the system throughput while satisfying QoS(Quality of Service) requirements by minimizing the difference between queueing delays in vehicle edge computing servers(VECSs). The results show that compared to other algorithms, the proposed algorithm achieves approximately 14-49% better QoS satisfaction and approximately 14-38% lower service blocking rate.

• Radiation Oncology Journal
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• v.36 no.4
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• pp.317-324
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• 2018

Purpose: This study aimed to evaluate the long-term survival outcomes and prognostic factors that affect the clinical outcomes of patients who underwent surgery and postoperative radiotherapy for major salivary gland mucoepidermoid carcinoma (MEC). Materials and Methods: We retrospectively reviewed the clinical data of 44 patients who underwent surgery followed by radiotherapy for primary MEC of the major salivary glands between 1991 and 2014. The median follow-up period was 9.8 years (range, 0.8 to 23.8 years). Results: The overall outcomes at 5 and 10 years were 81.5% and 78.0% for overall survival (OS), 86.2% and 83.4% for disease-free survival, 90.6% and 87.6% for locoregional recurrence-free survival, and both 90.5% for distant metastasis-free survival (DMFS). Histologic grade was the only independent predictor of OS (low vs. intermediate vs. high; hazard ratio = 3.699; p = 0.041) in multivariate analysis. A poorer survival was observed among patients with high-grade tumors compared with those with non-high-grade tumors (5-year OS, 37.5% vs. 91.7%, p < 0.001; 5-year DMFS, 46.9% vs. 100%, p < 0.001). Conclusion: Surgery and postoperative radiotherapy resulted in excellent survival outcomes for patients with major salivary gland MEC. However, high-grade tumors contributed to poor DMFS and OS. Additional aggressive strategies for improving survival outcomes should be developed for high-grade MEC.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.05a
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• pp.51-54
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• 2021

본 논문은 차량과 보행자 간 충돌 사고를 예측하는 V2P(Vehicle to Pedestrian) 서비스에서 보행자 휴대기기의 데이터 전송 시점을 동적으로 계산함으로써 불필요한 통신을 감소시켜 에너지 효율을 향상시키는 것을 목적으로 하며, MEC(Mobile Edge Computing) 기반 V2P 서비스를 제안하였다. V2P 서비스에서는 보행자와 차량 간 충돌 가능성을 예측하기 위하여 두 객체의 실시간 GPS 데이터가 요구된다. 이때 보편적으로 보행자에 비해 차량의 이동속도가 더 빠르기 때문에 보행자가 빠르게 이동해 들어오는 주변 차량에 발견될 수 있기 위해서는 자신의 위치에는 의미 있는 변화가 발생하지 않았더라도 차량 이동속도에 맞춘 빠른 주기로 차량 혹은 중앙 클라우드 서버로 자신의 데이터를 송신해야만 한다. 이 과정에서 보행자 휴대폰의 에너지가 급속하게 소모된다. 따라서 본 연구는 이러한 문제를 해결하기 위하여 MEC 서버를 배치한 V2P 서비스를 제안하였고, 보행자가 본인의 상태 정보를 활용하여 효율적인 다음 데이터 전송 시점을 계산할 수 있는 동적시점계산 알고리즘을 제안하였다.