• Journal of Practical Agriculture & Fisheries Research
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• v.25 no.3
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• pp.14-18
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• 2023

White leg shrimps cultured in an inland private aquaculture farm with low salinity waters showed abnormal swimming behavior and appetite reduction in July 2022. Then, gradual mortality was observed in the aquaculture farm. During the diagnosis, bacterial strain KNUAF-SHP3 was isolated from the hepatopancreas of the dead shrimps. Based on the sequence of 16S rRNA gene, KNUAF-SHP3 was proved to be Shewanella sp., clustering into a group with S. algae MARS 14 and S. chilikensis JC5T. According to the result of experimental infection test, all shrimps challenged with high concentrations, 2.1×108 CFU/ml and 2.1×109 CFU/ml showed apparent disease symptoms and the cumulative mortality rates reached 100% in 7 days post challenge. These results emphasized that Shewanella isolate in this study can be a potential pathogen of white leg shrimp cultured in low salinity water.

• The Korean Journal of Mycology
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• v.39 no.1
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• pp.16-21
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• 2011

Ginseng root rot caused by Cylindrocarpon destructans is one of the most destructive diseases of ginseng(Panax ginseng). We analyzed the features of the species through pathogenicity test and genetic diversity analysis of C. destructans in Korea, for its application as basic data to attempt for effective control. C. destructans isolated from rotted ginseng roots exhibited a variety of colonial colors on media. It was assumed that there may exist genetic diversity in the population by the diversity of pathogenicity among isolates observed when artificially inoculated into ginseng roots. Pathogenicity tests using ex vivo wound inoculation with agar mixture inoculation on ginseng roots were performed similar results as were observed appear to be useful for rapid pathogen inspection. According to RAPD analysis results, Korean C. destructans isolates formed a single genetic group which can be distinguished readily from closely related other fungi. C. destructans group was divided into two small groups. Therefore, we were able to confirm pathogenicity and genetic difference between the isolates in each of the groups of the pathogen.

• Korean Journal of Plant Resources
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• v.29 no.5
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• pp.555-563
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• 2016

The morphological characteristics and genetic relationships among 32 germplasms of Zanthoxylum schinifolium and Zanthoxylum piperitum collected from two farms in Korea were investigated. The traits with the most variability were seed color, leaf size, and spine size. The intraspecific polymorphism of Z. schinifolium and Z. piperitum was 96.5% and 60.3%, respectively. The genetic diversity and Shannon’s information index values ranged from 0.11 to 0.33 and 0.19 to 0.50, with average values of 0.26 and 0.42, respectively. Two ISSR primers (UBC861 and UBC862) were able to distinguish the different species. The genetic similarity matrix (GSM) revealed variability among the accessions ranging from 0.116 to 0.816. The intraspecific GSM for Z. schinifolium and Z. piperitum was 0.177-0.780 and 0.250-0.816, respectively. The GSM findings indicate that Z. schinifolium and Z. piperitum accessions have high genetic diversity and possess germplasms qualifying as good genetic resources for cross breeding. The clustering analysis separated Z. schinifolium and Z. piperitum into independent groups, and all accessions could be classified into three categories. Z. Schinifolium var. nermis belonged to independent groups. Comparison of the clusters based on morphological analysis with those based on ISSR data resulted in an unclear pattern of division among the accessions. The study findings indicate that Z. schinifolium and Z. piperitum accessions have genetic diversity, and ISSR markers were useful for identifying Z. schinifolium and Z. piperitum.

• Journal of Life Science
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• v.18 no.6
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• pp.753-758
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• 2008

Genus Hemerocallis is a herbaceous species and some species among their taxa are very important herbal medicines. We evaluated representative samples of the eight taxa in Korea with inter simple sequence repeats (ISSR) markers to estimate phylogenetic relationships within taxa of this genus. The studied taxa were Hemerocallis fulva L., H. fulva for. kwanso, H. dumortieri Morren, H. coreana Nakai, H. hongdoensis M.G.Chung & S.S.Kang, H. middendorffi Trautv. et Mayer, H. thunbergii Baker, H. minor Miller. In addition, we investigated the genetic variation and structure of Korean populations of these taxa. The mean genetic diversity was 0.098 across species, varying from 0.068 to 0.123. A low level of genetic variation was found in populations of Hemerocallis species. Specially, gene diversity for H. minor was maintained the highest among genus Hemerocallis. An indirect estimate of the number of migrants per generation (Nm=0.218) indicated that gene flow was not extensive among Korean populations of Hemerocallis species. The phylogenic tree showed distinct three clades. One includes H. fulva, H. fulva for. kwanso and H. middendorffi. Another includes three Hemerocallis species, H. dumortieri, H. thunbergii and H. minor. The H. coreana and H. hongdoensis were shown as the sister group to the second clades. Although the size of sampling was not large enough for eight Korean Hemerocallis species, the analyses of ISSRs will certainly provide an enhanced view on the phylogeny of species.

• Journal of Marine Bioscience and Biotechnology
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• v.1 no.3
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• pp.186-192
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• 2006

Short interspersed repetitive elements (SINEs) are dispersed throughout eukaryotic genomes. These SINEs have been shown to be excellent phylogenetic markers for the closed related species. In this report, we isolated two novel families of SINEs from the mud loach. The two SINE families, mlSINE-L and mlSINE-S, have genomic lengths of about 410bp and 270bp, respectively. 5' and 3' ends of the SINE families are well conserved and highly homologous to each of corresponding ends of RSg-1 and SmaI SINEs. Phylogenetic analysis shows that mlSINEs are unique to the mud loach. A dot blot hybridization experiment shows that mlSINE-L has an estimated copy number of $1{\times}10^3$ per $2{\times}10^9bp$ (2.8 pg) and is more frequently distributed at nuclear matrix attachment regions (MARs) than loop DNAs. The result suggests that mlSINEs may preferentially integrate in or near MARs.

• Korean Journal of Microbiology
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• v.36 no.3
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• pp.173-180
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• 2000

The intern1 spacer regions (ISR) between the 16s and 23s $1_RNA$ genes of Aeronzonus iwonii blogroupsobria and A. caviae were investigated by PCR fragment length typing and DNA sequencing. A. iwonii bv.sobria has a speciIic 16s-23s pattern of 2-4 fiagments ranging Goin 479-539 bp, with the exception of thespecies Aeron7onns cmiae, which has 3 fragments ranglog from 470-602 bp. In all of the.4 vei*onii bv. sobr,iaand A, caviae strains examined in this study, the 470-481bp Tragnent, designated TSR-1, invariably contained $tDNA^{uc(GAT)$ and $tDNA^{Ala(TGC)$ in contrast to ISR-2 (513-525 bp). ISR-3 (537-539 bp) and ISR-4 (568-602 bp)containing TEX>$tDNA^{Olu(ITC)$ A stretch of 20 nucleotides (178-197 bp) in the ISR-4 was conserved only wit11mA.caiiue, from which the A. caiiae specific primer, named prAC-F, was designed and used for PCR with aAcaviae coimnon reverse primer A PCR product of 450 bp was apparent alnong I , caiizne strains, but not ii1.4.ijeronii bv. sob~ia strains. The PCR product was oot detected t"-om strains belonging to A. hjili-o~~hila, Ebrio,aud the family Ef\ulcornertei,obncteriaceae. This study provides the first molecular tool for mdentifying the species 8.caviae.ing the species 8. caviae.

• Korean Chemical Engineering Research
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• v.61 no.2
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• pp.217-225
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• 2023

2,3-Butanediol (2,3-BDO), which is used in various fields such as cosmetics and fertilizers, is a high value-added substance and the demand for it is gradually increasing. 2,3-BDO produced from the fermentation of microorganisms not only contains by-products of fermentation, but also varies greatly in feed composition depending on fermentation conditions, so it is difficult to efficiently operate the separation process to reach the target purity of the product. Therefore, in this study, through dynamic optimization of the bio-based 2,3-BDO distillation process, the optimal control route was explored to control the 2,3-BDO concentration of the bottom product to 99 wt% or more, when feed concentration changes. Steady and dynamic state process simulation, proportional integral (PI) controller design, and dynamic optimization were sequentially performed. As a result, the error between the 2,3-BDO concentration and the set point of the bottom product was reduced by 75.2%.

• The Journal of the Korea Contents Association
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• v.22 no.8
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• pp.416-434
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• 2022

This study, for learners using online and offline tools, understood the structural relationship of user experience of smart learning app on continuous use intention through the technology acceptance model, and classified the learning type characteristics. In addition, based on the experience of using the smart learning app, we explored ways to improve the design of the user experience design for learning tools and contents. For this purpose, the usage perception of 84 middle and high school students of the developed smart learning learning app was investigated after using it for 2 months, and the data were analyzed using the PLS structural equation technique. The main results of this study are as follows. First, system and content user experience had a significant effect on perceived usability and perceived ease of use, and the effect on continued use intention through attitude was significant. Second, there was a significant difference in the effect of system user experience on perceived usefulness in multi-group comparative analysis and gender group. In the preferred learning group, it was the path from perceived ease of use and perceived usefulness to attitude and intention to continue using that showed a significant path difference. Third, as a result of classifying the most commonly used learning types by the multidimensional scale method, the types separated into low dimensions were found to be four types: offline sync type, online sync type, ubiquitous learning type, and self-direct learning type.

• Research in Plant Disease
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• v.14 no.1
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• pp.15-20
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• 2008

Three isolates of Cucumber mosaic virus (CMV) were isolated from weed hosts showing typical mosaic symptoms, and some properties of the viruses were investigated. CMV isolates, designated as Is-CMV, Jd-CMV and Pla-CMV from Isodon inflexus, Jeffersonia dubia and Phryma leptostachya var. asiatica, respectively, were identified and characterized by biological reaction in several host plants, serological property, dsRNA analysis, reverse transcription-polymerase chain reaction (RT-PCR), restriction fragment-length polymorphism (RFLP). All isolates systemically infected in Nicotiana benthamiana, Cucurbita pepo cv. Black beauty and Cucumis sativus, and did not reveal any differences in these host plants between the isolates. However, remarkable difference in the symptoms was found between the CMVs in Capsicum annuum. Is-CMV induced an asymptomatic symptoms, while Jd-CMV and Pla-CMV produced severe mosaic symptoms in C. annuum plants. In dsRNA analysis, all isolates revealed four major bands with estimated molecular size of 3.4, 3.2, 2.1 and 1.0 kbp. The cDNAs of coat protein gene of the isolates were amplified by RT-PCR using a genus-specific single pair primers that designed to amplify a DNA fragment of approximately ranging from 938 to 966 bp. By restriction mapping analysis using RFLP of the RT-PCR products as well as by serological properties of gel diffusion test, the CMV isolates belong to a typical members of CMV subgroup IA. This is the first report on the occurrence of CMV in the three weed hosts.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.2C
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• pp.131-142
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• 2002

It is Proposed thatthe Algorithm for Self healing to restoration the backup VP Occurrence Error in ATM Network. This study focuses on self-healing algorithm to restore failed VP. and backup-VP algorithm, one of the popular self-healing algorithm, is applied in this study. The problem with the existing algorithm is that when backup-VP is failed, there is no solution. This study proposes backup-VP algorithm to guarantee QoS in accordance with class. This study evaluates the effect of failure and proposes two algorithms. One is a disjointed path group to node pair class, and the other is one that applied different backup-VP case by case. Through simulation network restoring ability is compared, analyzed and synthesized.