• Korean Journal of Microbiology
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• v.55 no.3
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• pp.313-315
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• 2019

An anaerobic bacterial strain WCF-2 was isolated from cow dung in finding cellulose-degrading bacteria for use as silage additives. Strain WCF-2 showed a higher cellulolytic activity than Cellulosilyticum lentocellum DSM $5427^T$, the closest relative of strain WCF-2 (98.2% of 16S rRNA gene sequence similarity). We sequenced the complete genome of strain WCF-2 and compared it with that of C. lentocellum DSM $5427^T$. The OrthoANI value between the two strains was 97.9% thus strain WCF-2 was identified as C. lentocellum. The genome size of strain WCF-2 was 4,779,774 bp with a G + C content of 34.4%, 4,154 coding genes (CDS), 54 pseudo genes, and 142 RNA genes. Strain WCF-2 harbored seven cellulase genes, five of which showed low similarities with those of C. lentocellum DSM $5427^T$.

• Knowledge Management Research
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• v.22 no.4
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• pp.217-235
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• 2021

As 49% of the world's population uses social media platforms, communication and content sharing within social media are becoming more active than ever. In this environmental base, the one-person media market grew rapidly and formed public opinion, creating a new trend called sell-sumer. This study defined new types of influencers by product category by analyzing the subject concentration of the commercial/non-commercial keywords of influencers and the impact of the ratio of commercial postings on sales. It is hoped that influencers working within social media will be helpful to new sales strategies that are transformed into sell-sumers. The method of this study classifies influencers' commercial/non-commercial posts using Python, performs text mining using KoNLPy, and calculates similarity between FastText-based words. As a result, it has been confirmed that the higher the keyword theme concentration of the influencer's commercial posting, the higher the sales. In addition, it was confirmed through the cluster analysis that the influencer types for each product category were classified into four types and that there was a significant difference between groups according to sales. In other words, the implications of this study may suggest empirical solutions of social media sales strategies for influencers working on social media and marketers who want to use them as marketing tools.

• The Journal of the Korea Contents Association
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• v.22 no.6
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• pp.116-124
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• 2022

The purpose of this study is to examine the vertical and horizontal continuity between grades and publishers, respectively, by analyzing the readability of reading passages included in English textbooks for 5th and 6th grades of elementary school. In order to do so, a corpus was constructed with the reading passages contained in 10 textbooks, and the reading passages in each textbook were analyzed through Coh-Metrix. Also, it was examined whether there was a statistically significant difference between grades and publishers in readability through one-way ANOVA. The results are as follows. First, as a result of analyzing the difference in readability between publishers within the same grade, there was a statistically significant difference between fifth-grade textbooks in the L2 readability index. Second, as a result of analyzing the vertical continuity between grades within the publisher, the difficulty of textbook A was higher in grade 6 than grade 5 based on FRE and FKGL, which showed a statistically significant difference. On the other hand, when L2 readability was used as the standard, the difficulty of textbook B was lower in 6th grade than in 5th grade. This result seems to be because FRE and FKGL calculate readability based on sentence and word length, whereas L2 readability is based on content word overlap, word frequency, and syntactic similarity of sentences.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.5
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• pp.612-624
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• 2022

A novel Gram-positive, motile, non-spore forming aerobic marine bacterium, designated 107-1^T was isolated from tidal mud collected in Gyehwa-do, South Korea. Cells of strain 107-1^T were short rod or coccoid, oxidase negative, catalase positive and grew at 10-40℃ (with optimum growth at 25-30℃). It utilized menaquinones MK-7 and 8 as its respiratory quinones and its major fatty acids were anteiso-C_15:0 (37.9%), iso-C_16:0 (14.9%), and iso-C_14:0 (10.8%). Phylogenetic analysis based on 16S rRNA gene sequences revealed a distinct clade containing strain 107-1^T and close species Planococcus ruber CW1^T(98.52% sequence similarity), P. faecalis KCTC 33580^T(97.67%), P. kocurii ATCC 43650T(97.48%), P. donghaensis DSM 22276T(97.47%), and P. halocryophilus DSM 24743T(97.37%). Strain 107-1^T contains one circular chromosome (3,513,248bp in length) with G+C content of 44.6 mol%. Estimated ranges for genome to genome distance, average nucleotide identity, and average amino acid identity comparing strain 107-1^T with close taxa were 20.3-34.8%, 77.9-86.9%, and 73.6-92.8%, respectively. Based on polyphasic analysis, strain 107-1^T represents a novel species belonging to the genus Planococcus.

• Journal of Conservation Science
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• v.37 no.6
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• pp.807-820
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• 2021

A study on the Joseon Dynasty's furnace walls, excavated from south Korea, was conducted to identify the correlations and differences of the furnace walls found in Jeolla and Gyeongsang regions. Three ruins in the Jeolla region and two in the Gyeongsang region were selected for the analysis. The results showed a layer change depending on the degree of plasticity and difference in the number of layers and particle phase. Furthermore, although the temperature to be subjected to heat was divided into 1300℃ and 1100℃, it was not a phenomenon that appeared according to the region. Additionally, analysis result of major components revealed that the TiO₂ content of most samples does not exceed 1wt%, This means that the furnace did not smelt iron sand or smelted it into low-titanium sand. This study indicated a slight similarity between the furnace walls found in the two regions, and the correlation was determined based on the nature of the ruins, raw materials of the metals ores, and composition of the raw materials constituting the furnace walls.

• Journal of Conservation Science
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• v.38 no.3
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• pp.217-233
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• 2022

The remains found in Geumcheok-ri, Gyeongju are located in close proximity to the Ancient Tombs in Geumcheok-ri, Gyeongju (Historic Site) which were built between the late 5th and early 6th centuries, and these tombs are known to belong to the powerful rulers of that area. Using metallurgical techniques, this study was conducted on the iron objects obtained from the excavated remains in Geumcheok-ri, Gyeongju which are presumed to have a close relation to the nearby ruins that played an important role in the growth of Silla. To identify differences in manufacturing techniques based on the purpose of the iron objects, eight objects were selected after classifying them by use and the microstructure and non-metallic inclusions were investigated. The analyses results confirmed that the manufacturing process involved forging iron with a high or low carbon content to produce a particular shape, and that the carburization process was applied to iron post forging a shape to increase its strength when necessary. The mechanical properties were improved by selectively applying the steelmaking method and the heat treatment technique considering the functions of the parts, and the low temperature reduction was applied to the smelting process. Furthermore, in comparison with the iron objects excavated from the remains located in the center of Gyeongju and its outskirts, it is confirmed that there is similarity in the smelting and manufacturing techniques between these objects.

• Korean journal of applied entomology
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• v.61 no.3
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• pp.449-460
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• 2022

The morphology and whole genome sequence of Spodoptera exigua nucleopolyhedrovirus K1 (SeNPV-K1) isolated in Korea were analyzed for the use as an eco-friendly control source against S. exigua. The polyhedra of SeNPV-K1 was amorphous with a size of 0.6-1.8 ㎛, and there was no external difference with the previously reported SeNPV. As a result of analyzing the nucleotide sequence of the whole genome, it was composed of 135,756 bp, which is 145 bp more than that of the previously reported SeNPV. The G+CG+C content was 44% and there were 6 homologous repeated sequences, so there was no significant difference from the previous report. As a result of ORF analysis, SeNPV-K1 had 137, two fewer than those previously reported, and 4 ORFs present only in SeNPV-K1 were confirmed. These 4 ORFs are non-essential genes and were not considered to have a significant influence on the characteristics of the SeNPV. The genome vista analysis showed that the overall sequence similarity between SeNPV-K1 and the previously reported SeNPV was very high. The whole genome of SeNPV-K1 analyzed for the first time in Korea was found to be similar to the previously reported SeNPV, but it was confirmed that it was a novel resource in Korea with different isolate.

• Journal of Microbiology and Biotechnology
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• v.33 no.7
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• pp.909-914
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• 2023

While searching for the bacteria which are responsible for degradation of pesticide in soybean field soil, a novel bacterial strain, designated 5-5^T, was isolated. The cells of the strain were Gram-staining-positive, aerobic and non-motile rods. Growth occurred at 10-42℃ (optimum, 30℃), pH 5.5-9.0 (optimum, pH 7.0-7.5), and 0-2% (w/v) NaCl (optimum, 1%). The predominant fatty acids were C_15:0 anteiso, C_17:0 anteiso, and summed feature 8 (C_18:1 ω7c and/or C_18:1 ω6c). The predominant menaquinone was MK-9 (H₂). Diphosphatidylglycerol, glycolipids, phosphatidylinositol, and phosphatidylglycerol were the major polar lipids. Phylogenetic analysis of 16S rRNA gene sequences indicated that strain 5-5^T is a member of the genus Sinomonas and its closest relative is Sinomonas humi MUSC 117^T, sharing a genetic similarity of 98.4%. The draft genome of strain 5-5^T was 4,727,205 bp long with an N50 contig of 4,464,284 bp. Genomic DNA G+C content of strain 5-5^T was68.0 mol%. The average nucleotide identity (ANI) values between strain 5-5^T and its closest strains S. humi MUSC 117^T and S. susongensis A31^T were 87.0, and 84.3 % respectively. In silico DNA-DNA hybridization values between strain 5-5^T and its closest strains S. humi MUSC 117^T and S. susongensis A31^T were 32.5% and 27.9% respectively. Based on the ANI and in silico DNA-DNA hybridization analyses, the 5-5^T strain was considered as novel species belonging to the genus Sinomonas. On the basis of the results from phenotypic, genotypic and chemotaxonomic analyses, strain 5-5^T represents a novel speciesof the genus Sinomonas, for which the name Sinomonas terrae sp. nov. is proposed. The type strain is 5-5^T (=KCTC 49650^T =NBRC 115790^T).

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.1
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• pp.89-96
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• 2023

In this paper, a ferrosilicon by-product was evaluated to confirm the feasibility of recycling it as supplementary cementitious material of ordinary Portland cement in concrete. Three different levels of replacement ratio (10 %, 20 % and 30 % of total binder) were applied to find which is the most beneficial to be used as a binder. Ferrosilicon concrete was initially assessed at setting time and compressive strength. Durability was evaluated by the resistance to chloride penetration test(RCPT) and alkali-silica reaction(ASR) with a comparison to silica fume concrete due to their similarity in chemical composition. The porosimetry and X-ray diffraction analysis along with energy dispersive X-ray spectroscopy give information on the microstructural characteristics of the ferrosilicon concrete. It was found that 10 % ferrosilicon concrete has higher strength while 20 %, 30 % have lower strength than OPC concrete. However, chemical resistance to chloride attack is higher when replacement is increased. Compared to silica fume, the durability of ferrosilicon might be less efficient however, it is obviously beneficial than OPC. High SiO₂ content in ferrosilicon results in producing more C-S-H gel which could make denser pore structure. Most of the risk of alkali silica reaction to silicate binders through length change tests was less than 0.2 %, and both mortar using ferrosilicon and silica fume showed better resistance to alkali silica reaction as the substitution rate increased.Reuse of industrial waste rather than producing highly refined additives might reduce environmental load during manufacture and save costs.

• Journal of Microbiology and Biotechnology
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• v.33 no.10
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• pp.1292-1298
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• 2023

PAMB 00755^T, a bacterial strain, was isolated from Korean fir leaves. The strain exhibits yellow colonies and consists of Gram-negative, non-motile, short rods or ovoid-shaped cells. It displays optimal growth conditions at 20℃, 0% NaCl, and pH 6.0. Results of 16S rRNA gene-based phylogenetic analyses showed that strain PAMB 00755^T was most closely related to Sphingomonas chungangi MAH-6^T (97.7%) and Sphingomonas polyaromaticivorans B2-7^T (97.4%), and ≤96.5% sequence similarity to other members of the genus Sphingomonas. The values of average nucleotide identity (79.9-81.3%), average amino acid identity (73.3-75.9%), and digital DNA-DNA hybridization (73.3-75.9%) were significantly lower than the threshold values for species boundaries; these overall genome-related indexes (OGRI) analyses indicated that the strain represents a novel species. Genomic analysis revealed that the strain has a 4.4-Mbp genome encoding 4,083 functional genes, while the DNA G+C content of the whole genome is 66.1%. The genome of strain PAMB 00755^T showed a putative carotenoid biosynthetic cluster responsible for its antioxidant activity. The respiratory quinone was identified as ubiquinone 10 (Q-10), while the major fatty acids in the profile were identified as C_18:1ω7c and/or C_18:1ω6c (summed feature 8). The major polar lipids of strain PAMB 00755^T were diphosphatidylglycerol, phosphatidylethanolamine, sphingoglycolipid, and phosphatidylcholine. Based on a comprehensive analysis of genomic, phenotypic, and chemotaxonomic characteristics, we proposed the name Sphingomonas abietis sp. nov. for this novel species, with PAMB 00755^T as the type strain (= KCTC 92781^T = GDMCC 1.3779^T).